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Sample records for boom clay block

  1. Suction effects in deep Boom clay block samples

    CERN Document Server

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

    2008-01-01

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

  2. Boom clay pore water chemistry

    International Nuclear Information System (INIS)

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

  3. The Boom Clay geochemistry: Natural evidence

    International Nuclear Information System (INIS)

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

  4. On The Thermal Consolidation Of Boom Clay

    CERN Document Server

    Delage, Pierre; Cui, Yu-Jun

    2012-01-01

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

  5. On the thermal behaviour of Boom clay

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

  6. On the thermal behaviour of Boom clay

    International Nuclear Information System (INIS)

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

  7. Deformation mechanisms in experimentally deformed Boom Clay

    Science.gov (United States)

    Desbois, Guillaume; Schuck, Bernhard; Urai, Janos

    2016-04-01

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

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

    OpenAIRE

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

    2009-01-01

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

  9. Facts and features of radionuclide migration in Boom Clay

    International Nuclear Information System (INIS)

    The evolution which took place during ten years of research on the behaviour of radionuclides in Boom Clay is described. Initially, the Boom Clay was regarded as a chemically inert exchanger and the radiochemical research aimed at determining the distribution of cations between the clay and some liquid phases. The observation that Boom Clay deteriorates in contact with air and loses important intrinsic properties formed a major breakthrough in the research and led to a careful examination of the real in-situ conditions. Efforts devoted to the understanding of the chemical factors pertaining to the pH, the redox potential, the extent of the buffering capacity of FeS2 and CaCO3 in equilibrium with the interstitial aqueous phase are reviewed. Also emerging from the overall picture was the role of the organic material present in the Boom Clay. In contrast to the water percolating fractured formations which may not be in equilibrium with the rock, the interstitial aqueous phase is completely in equilibrium with Boom Clay mainly because of its low permeability and the large excesses of buffering components. As the retention mechanisms are better understood, a more coherent picture is obtained from distribution and diffusion experiments and the effects of consolidation are being investigated in detail. 23 refs.; 4 figs.; 3 tabs

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

    OpenAIRE

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

    2012-01-01

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

  11. The geochemical behaviour of uranium in the Boom Clay

    OpenAIRE

    Delécaut, Grégory

    2004-01-01

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

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

    OpenAIRE

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

    2009-01-01

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

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

    OpenAIRE

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

    2010-01-01

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

  14. Uranium release from boom clay in bicarbonate media

    International Nuclear Information System (INIS)

    The release of natural uranium from Boom Clay was studied to better understand the mechanisms governing the solid-liquid partitioning of uranium. Batch leaching experiments suggested that the portion of natural uranium released from clay is associated with colloids at a low bicarbonate concentration prevailing in Boom Clay. At increased bicarbonate concentrations, uranium was present predominantly as dissolved species indicating a formation of uranium carbonate complexes. The in situ aqueous uranium concentration, i.e., the concentration in the pore waters collected by piezometers was found to be 2 to 3 orders of magnitudes lower than the one measured by the batch techniques. These results illustrated that the batch techniques may cause a remobilization of uranium containing colloids from clay surfaces into solution when clay is suspended, agitated, and mechanically perturbed. These colloids are attributed to artefacts and are not considered to exist in situ because of the high compaction of Boom Clay. Due to the presence of colloids, a laboratory derived solid-liquid partitioning coefficient is not equivalent to and cannot simply be converted to the distribution coefficient Kd currently used in performance assessment calculations. (orig.)

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

    International Nuclear Information System (INIS)

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

  16. Static dissolution of UO2 in interstitial Boom Clay water

    International Nuclear Information System (INIS)

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

  17. The geochemical behaviour of selenium in Boom Clay

    International Nuclear Information System (INIS)

    For the disposal of high-level radioactive waste (HLW) in a deep geological formation such as the Boom Clay, safety assessment studies have shown that the long-lived 79Se (halflife presently reassessed to approximately 295 ka) is one of the more critical fission products. Therefore, the understanding of its migration properties (diffusion, retention, sorption, solubility) through the geological barrier is of prime importance. The migration behaviour of selenium strongly depends on its chemical speciation. Under the reducing conditions prevailing in Boom Clay, selenide, [Se(-II)], is the thermodynamically stable species, and HSe- is expected to be the dominant selenium species in solution. The selenium migration should mainly be controlled by the low solubility of iron selenide such as FeSe or FeSe2, or solid solutions with seleniferous pyrite. However Se species are often found in redox disequilibrium and more soluble higher oxidation state [selenite: Se(+IV), and selenate: Se(+VI)] might also coexist if their reduction is kinetically hindered. Due to the unknown oxidation state of selenium in the waste form and the uncertainties related to the redox disequilibrium it is important to study the behaviour of selenium in all its oxidation states. The aim of the study on the behaviour of selenium in Boom Clay is to understand its chemical speciation under in situ conditions and especially the redox stability of selenite (SeO32-) and selenate (SeO42-) whose reduction kinetics can be extremely slow. Then, to determine for the various selenium species present in solution, their solubility, their sorption distribution coefficient (Kd approach), and their diffusion coefficient in Boom Clay to provide relevant conceptual models and associated transport parameters for safety assessment purposes. To achieve this objective, an interdisciplinary study was undertaken by SCK-CEN for ONDRAF/NIRAS in close collaboration with KULeuven and AEA Technology

  18. Solubility limited retention of strontium in boom clay

    International Nuclear Information System (INIS)

    For over 25 years, the study of Boom Clay as a geological barrier to radioactive waste has focused on laboratory batch type and diffusion experiments using artificial tracers. These experiments may suffer from artefacts and are not always representative for natural conditions and the geological time scale. Only in recent years, the research has significantly taken natural evidences into account. An important objective of the natural evidence study is to test the models representing the retention of radionuclides by confronting the observed distribution of naturally present radionuclides. The distribution and retention of naturally present strontium in Boom Clay was studied for clay cores from recent drillings in HADES (Underground Research Facilities) 2001/4 and Mol-1 boreholes. The concentration of strontium was measured both on solid clay and in pore water extracted by mechanical squeezing from the clay cores. Strontium concentration was also determined in the pore water samples collected from a multi-filter piezometer installed in the HADES 2001/4 borehole. (authors)

  19. Homogeneity vs. Heterogeneity of Porosity in Boom Clay

    International Nuclear Information System (INIS)

    Microstructural investigations on Boom Clay at nano- to micrometer scale, using BIB-SEM methods, result in porosity characterization for different mineral phases from direct observations on high resolution SE2-images of representative elementary areas (REAs). High quality, polished surfaces of cross-sections of ∼ 1 mm2 size were produced on three different samples from the Mol-Dessel research site (Belgium). More than 33,000 pores were detected, manually segmented and analyzed with regard to their size, shape and orientation. Two main pore classes were defined: Small pores (< 500 nm (ED)) within the clay matrices of samples and =big' pores (> 500 nm (ED)) at the interfaces between clay and non-clay mineral (NCM) grains. Samples investigated show similar porosities regarding the first pore-class, but differences occur at the interfaces between clay matrix and NCM grains. These differences were interpreted to be due to differences in quantitative mineralogy (amount of non-clay mineral grains) and grain-size distributions between samples investigated. Visible porosities were measured as 15 to 17 % for samples investigated. Pore-size distributions of pores in clay are similar for all samples, showing log-normal distributions with peaks around 60 nm (ED) and more than 95 % of the pores being smaller than 500 nm (ED). Fitting pore-size distributions using power-laws with exponents between 1.56 and 1.7, assuming self-similarity of the pore space, thus pores smaller than the pore detection resolution following the same power-laws and using these power-laws for extrapolation of pore-size distributions below the limit of pore detection resolution, results in total estimated porosities between 20 and 30 %. These results are in good agreement with data known from Mercury Porosimetry investigations (35-40 % porosity) and water content porosity measurements (∼ 36 %) performed on Boom Clay. (authors)

  20. CO2 production from the Boom clay under thermal load

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Organic matter is an important constituent of the clayey rocks studied as natural barriers in the context of radioactive waste disposal. The Boom Clay, currently considered by the Belgian agency for radioactive waste and enriched fissile materials Ondraf/Niras as a potential host formation for geological disposal, contains a substantial amount of organic matter (0.5-5 wt%) of low maturity. Low maturity of the organic matter together with the other diagenetic indicators point to the fact that Boom Clay was never deeply buried and thus never experienced temperatures significantly higher than present T of 15-20 C in the course of its geological history. In contrast to past geological evolution, the temperature in the near-field of a repository for heat-emitting radioactive wastes in the Boom Clay can reach 80-90 C depending on the waste type, cooling time prior to disposal and gallery spacing. It is well documented that Boom Clay kerogen will release significant amounts of CO2 even under mild thermal stress. The production of gaseous compounds like CO2 under moderate thermal stress may have a significant impact on the physico-chemical parameters of the pore water in the near field of the repository and thus may affect speciation and migration behaviour of the radionuclides. Until now, a number of experiments have been performed to determine the source and total CO2 yields under variable conditions, time and temperature regimes. In this contribution, we bring an overview of the available results on the Boom Clay capacity to produce CO2 as a response to thermal stress, its implications for the pore water chemistry and we put forward some perspectives with respect to future research. Deniau et al. (2005) and Lorant et al. (2008) performed closed pyrolyses on the isolated Boom Clay kerogen of the same origin at T between 80 and 200 C. It is estimated that the maximum amount of 'labile' CO2 that can be generated by the

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

    International Nuclear Information System (INIS)

    The redox-sensitive fission product technetium-99 is of great interest in nuclear waste disposal studies because of its potential of contaminating the geosphere due to its very long half-life and high mobility. Under oxidising conditions, technetium is present as pertechnetate, a highly soluble, anionic species, that does not sorb significantly on minerals or sediments. Under suitable reducing conditions, eg. in the presence of a reducing solid phase which can act as an electron donor, the solubility can be limited by the reduction of pertechnetate followed by the formation of a surface precipitate with a low solubility. However, in the presence of dissolved humic substances, the solubility may be enhanced due to the formation of Tc-HS complexes. The geochemical behaviour of the redox sensitive Technetium-99 (Tc) in reducing clay environments and in the presence of organic matter, was elucidated with a number of lab-scale Boom Clay batch experiments. In a new set of experiments, the influence of FeS2 on the interaction of Tc with dissolved Boom Clay organic matter was elucidated in batch systems prepared in a similar manner as in Maes et al (2003). In a second set of experiments, the long-term (up to 113 days) behaviour of the Tc interaction with dissolved Boom Clay O.M. was studied. Finally, (ir)reversibility effects concerning the interaction of Tc(IV) with dissolved Boom Clay HS were investigated by examining newly installed equilibrium conditions upon interchanging of supernatants of Tc spiked and not-spiked Boom Clay suspensions. EXAFS measurements (Maes et al., 2004) of different series of experiments were made to further elucidate the nature and kind of Tc(IV)-humic substances species (Gorleben and Boom Clay humic substances ) and to identify Tc(IV) species formed on solid phases (pyrite and magnetite): series 1 consisted of Tc species in presence of 2 different iron-containing surfaces (acting as the necessary reducing solid phase): pyrite and magnetite

  2. ATLAS IV in situ heating test in Boom Clay

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. The small scale in-situ ATLAS (Admissible Thermal Loading for Argillaceous Storage) tests are performed to assess the hydro-mechanical effects of a thermal transient on the host Boom clay at the HADES underground research facility in Mol, Belgium. The initial test set-up, consisting of a heater borehole and two observation boreholes, was installed in 1991-1992. The first test (later named 'ATLAS I') was then performed from July 1993 to June 1996; during this time, the heater dissipated a constant power of 900 W. During the second phase ('ATLAS II'), the heating power was doubled (1800 W) and maintained constant from June 1996 to May 1997. This was followed by shutdown and natural cooling starting from June 1997 on. To broaden the THM characterization of the Boom clay at a larger scale and at different temperature levels, the test set-up was extended in 2006 by drilling two additional instrumented boreholes (AT97E and AT98E). The heater was switched on again from April 2007 to April 2008 with a stepwise power increase, followed by an instantaneous shutdown. This phase is called 'ATLAS III'. The above tests have provided a large set of good quality and well documented data on temperature, pore water pressure and total stress; these data allowed to make several interesting observations regarding the thermal anisotropy and THM coupling in the Boom clay. The straightforward geometry and well defined boundary conditions of the tests facilitate the comparison between measurement and numerical modeling studies. Based on the three dimensional coupled THM modeling of the ATLAS III test, the good agreement between measurement and numerical modeling of temperature and pore water pressure yields a set of THM parameters and confirms the thermo-mechanical anisotropy of the Boom clay. To get a better insight in the anisotropic THM behavior of the Boom clay, a new upward instrumented borehole was drilled above the ATLAS heater at

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  6. The study of abiotic reduction of nitrate and nitrite in Boom Clay

    International Nuclear Information System (INIS)

    In Belgium, Boom Clay is studied as a reference host rock for the geological disposal of high-level and intermediate-level radioactive waste. Compatibility studies at the SCK.CEN aim at investigating a perturbation of the capacity of Boom Clay to retard the migration of radionuclides to the biosphere, after disposal of Eurobitum bituminized radioactive waste in the clay (Valcke et al., 2009; Aertsens et al., 2009; Bleyen et al., 2010).One of the geo-chemical perturbations is the possible oxidation of Boom Clay by the large amounts of nitrate that will be released by Eurobitum. A more oxidised Boom Clay could have a lower reducing capacity towards redox sensitive radionuclides, possibly enhancing their migration. As the conditions in the Boom Clay formation around a disposal gallery for Eurobitum are far from optimal for the growth of prokaryotes (limited space in the far-field, high pH in the near-field, gamma radiation by the waste during the first ∼300 years (effect limited to the primary and secondary waste package)), the impact of microbially mediated reduction of nitrate and nitrite is unclear. Therefore, batch tests are performed at the SCK.CEN to study whether nitrate and nitrite can directly oxidise the main redoxactive components of Boom Clay (dissolved organic matter, kerogen, pyrite) without the mediation of prokaryotes. In a first series of batch tests, which are reported in this paper, the activity of denitrifying and nitrate reducing prokaryotes was inhibited by the addition of NaN3. NaN3 revealed to be an efficient inhibitor for these prokaryotes without affecting considerably the geochemistry of Boom Clay and/or Boom Clay pore water. Neither in batch tests with the Boom Clay slurries (with NaNO3 (0.1 and 1 M) or NaNO2 (0.1 M)) and with Boom Clay water (with 0.05 and 0.2 M NaNO3) a pure chemical nitrate or nitrite reduction was observed after respectively 3, 7 and 17 weeks and 1 year (Boom Clay slurries) and about 2 years (Boom Clay water

  7. The study of abiotic reduction of nitrate and nitrite in Boom Clay

    Science.gov (United States)

    Mariën, A.; Bleyen, N.; Aerts, S.; Valcke, E.

    In Belgium, Boom Clay is studied as a reference host rock for the geological disposal of high-level and intermediate-level radioactive waste. Compatibility studies at the SCK•CEN aim at investigating a perturbation of the capacity of Boom Clay to retard the migration of radionuclides to the biosphere, after disposal of Eurobitum bituminized radioactive waste in the clay ( Valcke et al., 2009; Aertsens et al., 2009; Bleyen et al., 2010). One of the geo-chemical perturbations is the possible oxidation of Boom Clay by the large amounts of nitrate that will be released by Eurobitum. A more oxidised Boom Clay could have a lower reducing capacity towards redox sensitive radionuclides, possibly enhancing their migration. As the conditions in the Boom Clay formation around a disposal gallery for Eurobitum are far from optimal for the growth of prokaryotes (limited space in the far-field, high pH in the near-field, gamma radiation by the waste during the first ∼300 years (effect limited to the primary and secondary waste package)), the impact of microbially mediated reduction of nitrate and nitrite is unclear. Therefore, batch tests are performed at the SCK•CEN to study whether nitrate and nitrite can directly oxidise the main redoxactive components of Boom Clay (dissolved organic matter, kerogen, pyrite) without the mediation of prokaryotes. In a first series of batch tests, which are reported in this paper, the activity of denitrifying and nitrate reducing prokaryotes was inhibited by the addition of NaN 3. NaN 3 revealed to be an efficient inhibitor for these prokaryotes without affecting considerably the geochemistry of Boom Clay and/or Boom Clay pore water. Neither in batch tests with the Boom Clay slurries (with NaNO 3 (0.1 and 1 M) or NaNO 2 (0.1 M)) and with Boom Clay water (with 0.05 and 0.2 M NaNO 3) a pure chemical nitrate or nitrite reduction was observed after respectively 3, 7 and 17 weeks and 1 year (Boom Clay slurries) and about 2 years (Boom Clay

  8. Technetium behaviour in Boom Clay - a laboratory and field study

    International Nuclear Information System (INIS)

    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 TcO2.1.6H2O in the solubility studies. From fitting the curves of the Tc concentrations as function of time, distribution coefficient (Kd) values were estimated to lie between 0.8 cm3 g-1 and 1.8 cm3 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.)

  9. Thermo-hydro-mechanical behaviour of Boom clay

    International Nuclear Information System (INIS)

    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)

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

    Science.gov (United States)

    Huysmans, Marijke; Dassargues, Alain

    2006-05-01

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

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

    OpenAIRE

    Huysmans, Marijke; DASSARGUES Alain

    2006-01-01

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

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

    OpenAIRE

    Huysmans, Marijke; DASSARGUES Alain

    2006-01-01

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

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

    International Nuclear Information System (INIS)

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

  14. In-situ PCO2 measurement in boom clay: the pegasus experiment

    International Nuclear Information System (INIS)

    Boom Clay has been studied for over twenty-five years as a potential host rock for the final disposal of radioactive waste. To assess the safety of the Boom Clay as a geological barrier, a good understanding of its geochemistry is essential as it reveals the stability of the host rock and influences the migration of radionuclides. A recent study on the geochemistry of Boom Clay pore water highlights the need of a representative value of the partial pressure of carbon dioxide (PCO2 ). Until now the used value of pCO2 of Boom Clay varies between 1,61 and 4,03 mbar (10-2.8 to 10-2.4 atm). A good solution to measure representative in-situ pCO2 values, is to use a set up in which the experimental boundaries are imposed and controlled by the Boom Clay formation itself. Under normal Boom Clay physico-chemical conditions, there is no gas phase present. This is because all volatile and gaseous species, thus also carbon dioxide, are below their saturation limit. They are only present as dissolved components of the Boom Clay pore water. This paper describes a new technique, based on the proportional Henry law relationship, to determine the in-situ pCO2. The main idea of the new pCO2 measurement technique is to bring Boom Clay pore water in contact with a chemically non reactive, inert, gas phase. As a consequence of this contact the dissolved carbon dioxide starts to transform into the gaseous phase. At equilibrium the distribution of the carbon dioxide between the gas and the liquid phase is proportionally related and defined by the Henry law constant. To make this new technique work under in-situ conditions the following experimental set up has been designed and constructed. (authors)

  15. Radionuclide solubilities in boom clay. Final report, part 1 : a report produced for ONDRAF/NIRAS

    International Nuclear Information System (INIS)

    The release of radionuclides from a High Level 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 has identified neptunium and technetium as critical elements for which the solubility limit in Boom Clay water may be important. Selenium, uranium and plutonium have also been found to be of potential concern. AEA Technology plc was therefore 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. As well as being of use in performance assessments, such data may aid the interpretation of laboratory migration studies being carried out in Belgium. The modelling described in this report involves the use of the HARPHRQ program to guide an experimental programme for the measurement of radioelement solubility in Boom Clay water. Although, the main interest to ONDRAF is for measurements at the expected in-situ conditions in the Boom Clay, experiments may be performed at a range of pH and Eh conditions to provide a more detailed understanding of the aqueous chemistry of these key elements and to provide data for testing of geochemical models. Therefore the modelling was performed over a pH range 4-10

  16. Developments in modelling of thermohydro-geomechanical behaviour of Boom clay and clay-based buffer materials (volume 2)

    International Nuclear Information System (INIS)

    This study is composed of two parts: The first part (Volume 1) lays the foundations of a comprehensive theoretical treatment of the interaction between water and soil skeleton during thermal dilatation. The second part (volume 2) is devoted to the development and the application of advance constitutive modelling of mechanical behaviour of clays taking into account the extensive tests of Boom clay reported in the first volume. The development concentrated on the improvement of prediction of the volumetric response of clay skeleton: (a) improving the dilatancy prediction at low to high overconsolidation ratios (Section 2). An elasto-plastic constitutive model has been developed to account for this effect (Section 3.2.); (b) modelling of swelling effects (Section 2.5). A preliminary interpretative model for swelling prediction has been developed (Section 2.5). The application part consisted in interpreting the experimental results obtained for Boom clay to calibrate a set of constants (Section 3) for performing numerical analyses (Section 4) for the thermomechanical model already calibrated for Boom clay (Appendix). Interpretation of the tests required an assessment of influence of the strong anisotropy effects revealed by Boom clay on the basis of an interpretative model characterized by a kinematic hardening plasticity and coupled elasticity (section 3)

  17. In-situ chemical osmosis experiment in boom clay at the underground research laboratory of Mol

    International Nuclear Information System (INIS)

    Clay rich layers have traditionally been regarded as natural protective covers in regional aquifers because of their low permeability. In the absence of water conducting features, these deposits provide the low flow environment required for waste containment. Comprehensive understanding of the physical and chemical processes that control water and solute transport through low permeability argillaceous formations and to the environment is a key factor for assessing their suitability as host rocks. The Boom Clay, an over consolidated marine Oligocene deposit, is considered as a potential host rock for radioactive waste disposal. For more than two decades, extensive hydraulic and hydrochemical research has been carried out in the Boom Clay at the HADES Underground Research Laboratory (URL) in Mol (Belgium). The main objective of the experiments conducted at the HADES URL has been to characterize the in-situ hydrogeological conditions, to determine the hydraulic parameters, and to study the mechanisms controlling the chemistry and the composition of the Boom Clay pore water. (authors)

  18. Creep behaviour in thermal and mechanical consolidation tests on Boom clay

    OpenAIRE

    Le, Trung Tinh; Cui, Yu Jun; Delage, Pierre

    2007-01-01

    Boom clay, a stiff clay from the Underground Research Laboratory (URL) at Mol (Belgium) may be the host medium for a long-term radioactive waste storage facility. To study the thermal-hydromechanical properties of this clay, an experimental investigation was carried out on a testing system permitting high pressure triaxial tests at controlled temperature. Thermal and mechanical consolidation tests were carried out, following isobar heating and isothermal compression paths. The results showed ...

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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

  3. Selenite reduction in boom clay: effect of FeS2, clay minerals and dissolved organic matter

    International Nuclear Information System (INIS)

    In Belgium, the Boom clay layer is considered as the candidate host rock for the disposal of high-level radioactive waste (HLRW). For this disposal, Selenium 79 is considered to be a critical radionuclide and responsible for the highest dose to man over a period of tens of thousands of years. The behaviour and reactivity of Se thereby depend on its speciation and on its complex biogeochemical transformations. 79Se is thought to occur in, and be released from the solid waste matrix in a variety of redox states, including Se oxyanions such as SeO32- or SeO42-. The composition of the solid and liquid phases of Boom clay was published before. In this paper, the reduction of Se oxyanions was investigated by adding appropriate amounts of SeO32- in over-saturation with respect to the proclaimed thermodynamical solubility of reduced Se solid phases (SeO, FeSe, FeSe2), to a number of systems which represent Boom clay geochemical conditions. The range of systems is chosen in order to incorporate in an increasing way the different Se competing organic and inorganic phases present in the Boom clay matrix. (authors)

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Boom clay has been selected as a potential host hock formation for the geological disposal of radioactive waste in Belgium. At Mol site, an Underground Research Laboratory (URL) was built at a depth of about 223 m to study the feasibility to dispose the High Level Waste (HLW) in Boom clay formation. Since the construction of the URL about 30 years ago, many thermo-hydro-mechanical experimentations have been carried out around the excavations. The Essen site is located in the north-east of Belgium, about 60 km far from Mol and has been considering as an alternative site. Borehole was drilled at Essen site in order to make fundamental geological, hydraulic, geochemical investigation of Boom clay at that site. Soil cores at different depths were taken for geo-mechanical characterisation. In the present work, the hydro-mechanical behaviour of Boom clay taken from the Essen site was investigated in laboratory and the results were compared with that of the Boom clay taken from the URL at Mol. Four cores of Boom clay were taken at various depths. The identification physical-geotechnical properties such as specific gravity Gs, liquid limit wL, plastic limit wP, plasticity index IP, blue methylene value VBS, and carbonate content (CaCO3) are shown. In addition, some properties corresponding to its initial state (water content wi and void ratio e0) are equally shown. It can be noted that the soils from the two sites present similar physical-geotechnical properties. The only difference lies in the initial void ratio: the Boom clay at Essen presents a larger void ratio. Different mechanical tests have been run. First, oedometer tests were performed in order to study the compressibility and the permeability of the soil. Loading and unloading paths were followed in steps for a wide range of vertical stress (from 0.05 to 32 MPa). The compression index Cc and the swelling index Cs as well as the pre-consolidation stress σv0 were

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

    OpenAIRE

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

    2009-01-01

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

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

    OpenAIRE

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

    2012-01-01

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

  8. Diffusion and sorption of 32Si-labelled silica in the boom clay

    International Nuclear Information System (INIS)

    The long term corrosion rate of nuclear waste glass in a repository might be controlled by the steady-state diffusion of dissolved silica and would be enhanced by the sorption of silica onto clay minerals. Irreversible sorption and moderate retardation have been observed for dissolved silica in boom clay. Values of ηR between 10 and 20 have been determined by means of four flow-through migration experiments, while Kd in the range 20 to 100 cm3, g-1 have been measured by batch sorption tests with 32Si on fresh and slightly oxidized boom clay. As non specific interactions cannot explain the sorption of neutral Si(OH)4, or of negative silicate species (Donnan exclusion), onto negatively charged clay minerals other mechanisms must be invoked: i.a., the chemisorption of dissolved silica Si(OH)4 onto specific Lewis acid sites (Al3+, Fe3+) present at the clay surface. The suggested mechanism could be similar to this explaining the irreversible chemisorption of oxy-anions of weak acids (as phosphate, or borate) onto aluminum and iron hydroxides in soils. Ligand exchange of aqueous silica with a hydroxyl group of Al(OH)3 may form a hydroxy-aluminosilicate (HAS) surface complex. Gibbsite layers accessible on the basal plane of kaolinite and on the edges of illite and smectite are possible sorption sites for the dissolved silica in boom clay. Moreover, hydrous ferric oxide produced by pyrite oxidation significantly increases the extent of silica sorption. (orig.)

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

    International Nuclear Information System (INIS)

    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 (99Tc) under Boom Clay conditions has been drafted. In brief, the stable oxidation state of 99Tc in these conditions is +IV, and, therefore, Tc solution concentrations are limited by the solubility of TcO2.nH2O(s). However, during reduction of TcVII (in the TcO4- form) to TcIV, precursor TcO2.nH2O 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 independent study on

  10. Characterization of groundwater flow in the environment of the Boom Clay formation

    International Nuclear Information System (INIS)

    Since 1975, the possibility to dispose of high-level radioactive waste in the Boom Clay formation has been investigated in Belgium at the test site in Mol. This research involves detailed studies of the hydrogeological system at various scales, observations of groundwater levels in the regional and local piezometric networks, several site investigations including geophysics and core-drilled boreholes. The knowledge gained during the long-term hydrogeological research is integrated in groundwater models. Major differences in the groundwater regimes above and below the Boom Clay gave rise to two models simulating these two sub-systems separately. The Neogene aquifer model is used to simulate the groundwater flow above the Boom Clay and the Deep aquifer pumping model to simulate the groundwater flow below the Boom Clay. The regional groundwater research improved the understanding of the regional flow system, since it has enabled to explain the behaviour of the aquifer system using a combination of a steady-state model for the Neogene aquifers and a transient model for the deep aquifers. This combination of modelling tools can offer a representative set of boundary conditions for the consecutive models that will depend on the scenarios required for the performance assessment of the integrated repository system. (authors)

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

    International Nuclear Information System (INIS)

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

  12. 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.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  15. Hollow Cylinder Tests on Boom Clay: Modelling of Strain Localization in the Anisotropic Excavation Damaged Zone

    Science.gov (United States)

    François, Bertrand; Labiouse, Vincent; Dizier, Arnaud; Marinelli, Ferdinando; Charlier, Robert; Collin, Frédéric

    2014-01-01

    Boom Clay is extensively studied as a potential candidate to host underground nuclear waste disposal in Belgium. To guarantee the safety of such a disposal, the mechanical behaviour of the clay during gallery excavation must be properly predicted. In that purpose, a hollow cylinder experiment on Boom Clay has been designed to reproduce, in a small-scale test, the Excavation Damaged Zone (EDZ) as experienced during the excavation of a disposal gallery in the underground. In this article, the focus is made on the hydro-mechanical constitutive interpretation of the displacement (experimentally obtained by medium resolution X-ray tomography scanning). The coupled hydro-mechanical response of Boom Clay in this experiment is addressed through finite element computations with a constitutive model including strain hardening/softening, elastic and plastic cross-anisotropy and a regularization method for the modelling of strain localization processes. The obtained results evidence the directional dependency of the mechanical response of the clay. The softening behaviour induces transient strain localization processes, addressed through a hydro-mechanical second grade model. The shape of the obtained damaged zone is clearly affected by the anisotropy of the materials, evidencing an eye-shaped EDZ. The modelling results agree with experiments not only qualitatively (in terms of the shape of the induced damaged zone), but also quantitatively (for the obtained displacement in three particular radial directions).

  16. Effect of excavation induced fractures on radionuclide migration through the boom clay (Belgium)

    International Nuclear Information System (INIS)

    In Belgium, the Boom Clay at a depth of 200 m below surface is being evaluated as a potential host formation for the disposal of high-level nuclear waste. In order to investigate this option, an underground research facility composed of two access shafts and a 200 m long gallery was excavated in the Boom Clay for research purposes (HADES-URF). Around the gallery, excavation induced fractures are observed. The majority of these fractures are approximately parallel planes with an average spacing of around 70 cm, a strike approximately perpendicular to the tunnel axis and a dip between 30 and 70 degrees. fracturing and self-sealing processes in Boom (and Opalinus) Clay were studied in the EC SELFRAC project (EC contract FIKW-CT2001-00182). The research performed in the framework of this project shows that the excavation induced fractures around the connecting gallery are limited to a zone of 1 m. This gallery was excavated using an industrial technique and with minimal radial convergence. Moreover self-sealing processes, which will further limit the influence of these fractures, have clearly been demonstrated in laboratory and in-situ experiments. The potential effect of these excavation induced fractures on the radionuclide migration through the clay is investigated in this study under the conservative assumption that no self-sealing occurs. A hydrogeological model of the clay is built with a radionuclide source in the middle of the clay surrounded by different fracture configurations. The radionuclide flux through the upper and lower boundaries of the clay into the surrounding aquifers is calculated and compared for different fracture configurations. (authors)

  17. Stability of 125I and 14C labelled boom clay organic matter

    International Nuclear Information System (INIS)

    The candidate host formation for the disposal of radioactive waste in Belgium is boom clay which may contain up to 4% organic matter (OM). A limited fraction (less than 0.05%) of this OM is mobile. OM can complex radionuclides and so influence their migration. The migration behaviour of the OM itself has been extensively studied but to date such studies have used absorbancy measurements to quantify the OM. Unfortunately various problems accompany the use of absorbancy measurements. The particular problems may be overcome by using radiolabelled OM. Accordingly as a precursor to planned in situ migration experiments in boom clay (BC) using radiolabelled OM, stability studies on 125I and 14C labelled materials have been conducted. The 125I containing solutions were analysed using gel permeation chromatography (GPC) and the 14C solutions using high performance size exclusion chromatography (HPSEC). Dissappointingly at the relevant pH of 8.5, even in the absence of the clay, the 125I label was found to be unstable. However the 14C labelled OM (14C-BC-OM) was stable under the mild conditions employed in the test, so its stability was investigated in the presence of boom clay. The results were compared with that of 14C labelled humic acids (14C-HA), treated similarly. Unexpectedly the 14C labelled material was found to be partially unstable in the presence of boom clay. However the instability has not hampered the laboratory column experiments and should not hamper the proposed in situ experiments with this material. (orig.)

  18. The treatment of gas in the performance assessment for the disposal of HLW and MLW in boom clay

    International Nuclear Information System (INIS)

    In Belgium the Boom Clay is studied as potential host rock for the geological disposal of high level (HLW) and intermediate level radioactive waste (ILW). The Boom Clay has been chosen because of its very low hydraulic conductivity (2 10-12 m/s). Consequently, transport of contaminants in pore water of the Boom Clay is diffusion-controlled whereas advection has a negligible contribution to the overall migration. Also the transport of dissolved gas is very limited. Therefore, when gas is generated this can easily lead to a gas pressure build-up and thus to a safety concern. In the following sections the experimental evidence about gas generation and transport in Boom Clay are briefly summarised, then the approach used to treat the gas issue, followed by the assessment of the gas generation and the assessment of its potential consequences. (authors)

  19. Joint effects of osmotic and matric suctions on hydro-mechanical behaviour of Boom Clay

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. One long-term management option of the Belgian Agency for the Management of Radioactive Waste and Fissile Materials (ONDRAF/NIRAS) is the direct underground disposal of Eurobitum Bituminized radioactive Waste (BW) in Boom Clay. In Geological disposal conditions, contact of the BW which contains large amounts of highly soluble NaNO3 with groundwater will result in water uptake and swelling of the waste and in subsequent diffusion of the dissolved salt through the host clay formation. Within the framework of the compatibility of Boom Clay with large amounts of nitrate-bearing bituminized radioactive waste an experimental research program have been started to investigate the effect of the leaching of large amounts of sodium nitrate on hydro-mechanical behaviour of Boom Clay. Change of pore water chemistry can affect clays through a variety of adsorption/desorption phenomena driven by osmotic suction (concentration) effects and cationic exchange mechanisms. For Boom Clay the dominant cation present is sodium ion Na+ at a concentration of about 10-2 mol/l. Therefore, when Boom Clay is exposed to NaNO3, cation exchange effects are expected to be negligible compared to osmotic suction effects. Indeed, two processes are expected to take place, chemical consolidation and chemically induced consolidation. Chemical consolidation occurs due to the transfer of mass of water and salt from the pore space into the inter-lamellar space and/or external surface of clusters and vice versa. Chemically induced consolidation is due to the osmotic flow of water out of the sample that takes place in response to the chemical (concentration) gradient. The relevance of osmotic suction effects has been addressed by Mokni (2011) and a formulation has been proposed for the analysis of deformation induced by osmotic processes in double structure porous media. The formulation is based on the distinction within the material of a microstructural

  20. Solid/liquid distribution of radiocesium in boom clay. A quantitative interpretation

    International Nuclear Information System (INIS)

    An interpretative study is presented on the in situ KD-value of radiocesium in Boom clay, a potential high level waster repository in Belgium. The solid/liquid distribution coefficient (KD) of radiocesium in the system is quantitatively interpreted in terms of the number of micaceous specific sites, the ionic composition of the interstitial liquid phase (K, Na) and the ion selectivity pattern (Cs/K, K/Na) in the specific sites. (orig.)

  1. The effect of gamma radiation on the dissolution of high-level waste glass in boom clay

    International Nuclear Information System (INIS)

    The effect of γ-radiation on the dissolution of candidate high-level waste glasses was investigated in potential disposal environments at 90 deg C. The media consisted of mixtures of Boom Clay, bentonite clay and cement with clay water. During the experiments the pH of Boom Clay decreased, probably mainly by radiolytical oxidation of pyrite. The addition of bentonite, cement and glass buffered the pH decrease. Under radiation the glass mass losses decreased, whereas the leach rate of soluble elements was not influenced or appeared to increase. This is explained through the radiolytical acidification, and possibly by bubble formation in the glass. Copyright (2001) Material Research Society

  2. 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)

  3. Studying the migration behaviour of radionuclides in boom clay by electromigration

    International Nuclear Information System (INIS)

    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 137Cs+ and 226Ra2+ 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.)

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

    International Nuclear Information System (INIS)

    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 (80OC) 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 80OC. The effect is due, at least in part, to the expansion of the pore fluid

  5. Modelling transport of 14C-labelled Natural Organic Matter (NOM) in Boom Clay

    International Nuclear Information System (INIS)

    In Belgium, the Boom Clay formation is considered to be the reference formation for HLW disposal R and D. Assessments to date have shown that the host clay layer is a very efficient barrier for the containment of the disposed radionuclides. Due to absence of significant water movement), diffusion - the dominant transport mechanism, combined with generally high retardation of radionuclides, leads to extremely slow radionuclide migration. However, trivalent lanthanides and actinides form easily complexes with the fulvic and humic acids which occur in Boom Clay and in its interstitial water. Colloidal transport may possibly result in enhanced radionuclide mobility, therefore the mechanisms of colloidal transport must be better understood. Numerical modeling of colloidal facilitated radionuclide transport is regarded an important means for evaluating its importance for long-term safety. The paper presents results from modeling experimental data obtained in the framework of the EC TRANCOM-II project, and addresses the migration behavior of relevant radionuclides in a reducing clay environment, with special emphasis on the role of the Natural Organic Matter (NOM)[1]. Percolation type experiments, using stable 14C-labelled NOM, have been interpreted by means of the numerical code HYDRUS-1D[2]. Tracer solution collected at regular intervals was used for inverse modeling with the HYDRUS-1D numerical code to identify the most likely migration processes and the associated parameters. Typical colloid transport submodels tested included kinetically controlled attachment/detachment and kinetically controlled straining and liberation. (authors)

  6. Assessing the spatial continuity of low permeability media for deep waste disposal: the Boom Clay case

    International Nuclear Information System (INIS)

    The Boom Clay is currently investigated as potential host formation for the deep disposal of high-level and/or long-lived radioactive waste in Belgium. Deep disposal safety relies on multiple barriers: the 'super-container' containing the vitrified waste, the repository itself and the host formation in which the disposal could be constructed. The latter is the most important as it is the one that has to slow the migration of radionuclides towards the biosphere for a sufficiently long time when the man-made barriers are no longer effective. So it is the site's geology that must ensure that the long-term radiological impact of the waste in the repository stays below the nationally and internationally allowable limits and is therefore significantly lower than natural radioactivity. The Boom Clay is a marine Oligocene clay of approximately 100 m thick deposited in the North Sea basin. It is known in Germany, The Netherlands and Belgium as a continuous layer gently dipping (∼1 deg.) towards the north-north-east but also gaining thickness in this direction. One of the most remarkable characteristics of the Boom Clay is its structure of bands that are several tens of centimeters thick, reflecting mainly cyclical variations in grain size (silt and clay content). The Boom Clay aquitard requires to be precisely characterized in terms of hydrogeological parameters, to confirm its role of geological barrier between its surrounding aquifers. Therefore, hydraulic conductivity and diffusion parameters have been intensively measured at only a few boreholes in Belgium, mainly located in the Mol-Dessel area, assuming a good lateral continuity of the geology. Combining these measurements with more densely acquired geophysical information allows quantifying their spatial variability and consolidating the continuity assumption. From a methodological point of view, the 3D modeling of hydrogeological parameters requires to solve several issues. First, it is required to find a

  7. The design of a large scale heater test in boom clay - the Praclay experiments

    International Nuclear Information System (INIS)

    PRACLAY aims to demonstrate the suitability of the Boom Clay host rock, in terms of performance of the disposal, to undergo the thermal load induced by the vitrified HI. PRACLAY represents an important milestone for the Safety and Feasibility Cases 1 (2013) and II (2020). PRACLAY is developed to be design-independent to overcome possible future changes in the design. The temperature criterion is: The maximum temperature in clay-based backfill materials, used as engineered barriers, for heat producing radioactive waste, must be kept below 100 C. PRACLAY regroups a set of four experiments. The PRACLAY Crossing consists in the intersection of the connecting gallery and the PRACLAY gallery, and aims to demonstrate that it is possible to construct a crossing between an access gallery and a disposal gallery at an acceptable cost and limiting the perturbation in the host-rock. The PRACLAY Heater Test has to demonstrate that Boom Clay will behave as predicted under a thermal load. The PRACLAY Plug Test is aimed at demonstrating that it is possible to cut-off hydraulically the Excavation Damaged Zone (EDZ) and the engineered barriers of the disposal galleries with a horizontal plug. 4. The PRACLAY backfill test aims to test the installation and the performance of different types of backfill or buffer material (cement, slaked lime, bentonite, Boom Clay...) that could be considered in the design of disposal galleries. The paper will present the objectives, the preliminary model predictions, and, as a result of these, the design of the test, including the monitoring plan and the choices regarding the boundary and initial conditions. (authors)

  8. Modelling of cation concentrations in the outflow of NaNO3 percolation experiments through Boom Clay cores

    International Nuclear Information System (INIS)

    A laboratory percolation experiment was performed to study the effect of a NaNO3 plume on the Boom Clay. In this experiment, Boom Clay cores were consecutively percolated with Boom Clay pore water and Boom Clay pore water to which NaNO3 was added. The concentration of NaNO3 in the pore water was increased stepwise (0.1, 0.5, and 1 M NaNO3). The concentrations of Na, K, Ca, Mg and Sr in the eluted water were measured. After every switch of the NaNO3 concentration, the concentration profiles of K, Ca, Mg, and Sr showed a sharp rise, followed by a slow decrease. It was hypothesised that the cation elution curves are mainly determined by cation exchange processes. Reactive coupled transport modelling with the PHREEQC-2 code was used to describe the experimentally observed elution curves for the cations. Solute transport and water-clay interaction mechanisms, namely cation exchange, were accounted for in the model. Cation exchange parameters (cation exchange capacity and selectivity coefficients) previously determined on non-perturbed Boom Clay (De Craen et al., 2004) were used. A sensitivity analysis was performed to assess the influence of these parameter values on the goodness of the model to describe the experimental data. The model could fairly well describe the experimentally observed cation concentrations in the eluted water, confirming that cation exchange is indeed the dominant mechanism regulating the cation elution in the percolation experiments. (authors)

  9. Variability in the hydraulic conductivity of the Boom clay in the Campine Basin, NE-Belgium

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In the framework the Belgian research program on the long term management of high-level and/or long-lived radioactive waste coordinated by ONDRAF/NIRAS, the Boom Clay has been investigated for more than 30 years as a candidate host formation for the disposal of high-level and long-lived radioactive waste in Belgium. The very low hydraulic conductivity (on the order of 10-12 m/s) in combination with limited hydraulic gradients over the host formation (0.02 ∼ 0.04 m/m) results in water flow in the Boom Formation being negligible and diffusion the dominant transport mechanism. The assessment of the long-term barrier function of the host clay formation in the framework of radioactive waste disposal requires rigorous quantitative characterization of key formation properties such as the hydraulic conductivity (K). Hydraulic conductivities of Boom Clay measured through various testing techniques in the laboratory, i.e. tracer percolation experiments, constant head permeameter experiments and isostatic experiments, exhibit similar K values in the order of 10-12 m/s. Based on a large set of test samples, the impact of sample scale, hydraulic gradient range adopted in the tests, stress controlled methods and pre-existing fissures in the sample on the K value is shown to be quite limited. In situ measurements obtained from both several-centimetre long piezometer filters and percolation into a 7-metre long gallery and 21-meter long shaft at the HADES underground research facility yield K values that are very similar to values measured in the laboratory on samples of a few centimetres. This indicates that the K measurements for the Boom Clay obtained through various techniques are very consistent. K values measured on a centimetre-scale are also representative at the metre-scale, which is often the size of grid cells used in numerical simulations for long-term safety assessments. Spatial analysis of K values across the Boom

  10. Numerical investigation of the seismic detectability of carbonate thin beds in the Boom Clay formation

    Science.gov (United States)

    Carcione, José M.; Gei, Davide

    2016-04-01

    The present study evaluates the capacity of the Boom Clay as a host rock for disposal purposes, more precisely its seismic characterization, which may assess its long-term performance to store radioactive wastes. Although the formation is relatively uniform and homogeneous, there are embedded thin layers of septaria (carbonates) that may affect the integrity of the Boom Clay. Therefore, it is essential to locate these geobodies. The seismic data to characterise the Boom Clay has been acquired at the Kruibeke test site. The inversion, which allowed us to obtain the anisotropy parameters and seismic velocities of the clay, is complemented with further information such as log and laboratory data. The attenuation properties have been estimated from equivalent formations (having similar composition and seismic velocities). The inversion yields quite consistent results although the symmetry of the medium is unusual but physically possible, since the anisotropy parameter ɛ is negative. According to a time-domain calculation of the energy velocity at four frequency bands up to 900 Hz, velocity increases with frequency, a behaviour described by the Zener model. Then, we use this model to describe anisotropy and anelasticity that are implemented into the equation of motion to compute synthetic seismograms in the space-time domain. The technique is based on memory variables and the Fourier pseudospectral method. We have computed reflection coefficients of the septaria thin layer. At normal incidence, the P-wave coefficient vanishes at specific thicknesses of the layer and there is no conversion to the S wave. For example, calculations at 600 Hz show that for thicknesses of 1 m the septarium can be detected more easily since the amplitudes are higher (nearly 0.8). Converted PS waves have a high amplitude at large offsets (between 30 and 80 degrees) and can be useful to identify the target on this basis. Moreover, we have investigated the effect of septaria embedded in the

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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 NaNO3 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

  13. Migration behaviour of 14C labelled bicarbonate, HTO and 131I in boom clay

    International Nuclear Information System (INIS)

    Performance assessment studies for the deep geological disposal of radioactive waste in the Boom clay indicated the importance of the radionuclides 14C and 129I. The migration properties of these radionuclides in Boom clay are studied by Flow-Through type diffusion experiments. In the diffusion tests a mixture of 14C labelled bicarbonate, tritiated water (HTO) and carrier free 131C labelled bicarbonate, tritiated water (HTO) and carrier free 131I sodium iodide (NaI) is used. The isotope 131I is used as an equivalent for 129I. The mixture allows for a good comparison of the migration behviour of the three different species. The mean value of the diffussion constant for bicarbonate is 1.8x10-6, for iodide 4.2x10-6 and for tritiated water 6.2x10-6 cm2.s-1. For the interpretation of the experiments we consider sorption (isotopic exchange), diffusion and first order chemical reaction. The results of the diffusion tests are consistent with the concept of the diffusion accessible porosity and proves the importance of this concept. The diffusion accessible porosity for both bicarbonate and iodide is 0.11. The results are important for the safety assessment of a radioactive waste repository in the clay formation. (orig.)

  14. Colloids formation versus complexation in radionuclides natural organic matter interaction studies: the case of Boom clay

    International Nuclear Information System (INIS)

    Full text of publication follows: Complexation of radionuclides (RN) by Natural Organic Matter (NOM) present in the host rock may pose a negative impact on the safety of a radioactive waste repository. This is because the formed complexes may increase the solubility, decrease the sorption, and thus enhance the mobility of RN. For Boom Clay, the reference host formation in Belgium for methodological research, and the one with probably the most abundant NOM content among the studied sites in the world, such a negative impact has not been demonstrated. This paper illustrates that Boom Clay NOM plays only a negligible role in RN complexation, based on data produced by the EC project TRANCOM-II. Classic approaches use a conditional stability constant (CSC) to measure the extent of interaction between RN and NOM. Such approaches borrow the theories from aquatic chemistry and model NOM as a complexing ligand. At neutral to alkaline pH, the condition relevant for most of disposal sites, side reactions such as hydrolysis and carbonate complexation interfere with the formation of RN-NOM complexes so that a CSC is highly conditional. Most of the published CSC values are very large implying high stabilities of formed RN-NOM complexes. A large value of a CSC predicts an increase in solubility and, if the formed RN-NOM complex is not sorbed, a decrease in sorption. Such predictions should be tested, before applied in safety assessments, by solubility and sorption experiments under relevant disposal conditions. Solubilities of laboratory prepared, amorphous tetravalent uranium and thorium phases were determined under geochemical conditions of Boom Clay with varying concentrations of NOM, mainly humic acid. Experimental results showed that Boom Clay NOM did not have an observable impact on the solubility of U(IV) and Th. For both actinides, however, NOM facilitated the formation of U/Th bearing colloids resulting in an apparent increase of U(IV) and Th concentration 3 orders of

  15. In situ and laboratory migration experiments through boom clay at Mol

    International Nuclear Information System (INIS)

    Physico-chemical characterization and migration studies in the Boom clay, envisaged as a potential host sediment for high level waste disposal in Belgium, were started some 15 years ago. A synthesis study of this experimental work has recently been conducted to compile all available data. From a comparison of the available migration data and the data requirements as derived from the performance assessment studies PAGIS (1988) and PACOMA (1991) the new migration programme (1991-1995) was defined. The critical radionuclides, both with relation to dose rates to man and to missing or unreliable migration data, turned out to be 14 C, 99 Tc. 135 Cs and 237 Np. A second group of radionuclides was found to be possibly critical: 79 Se, 93 Zr, 107 Pd, U-, Am-, Cm-, and Pu-isotopes. This report concentrates on the experimental results as obtained from the migration experiments started in the previous migration programme. Some of the reported radionuclides e.g. 90 Sr) have lost their critical character and will not be further studied within the new programme. New experimental data from laboratory tests have become available for Np, Cs, Sr and C (as HC03-) and the first results on the migration of organic molecules dissolved in the interstitial Boom clay water are reported. The hydraulic parameters (the hydraulic conductivity K and the storage coefficient So) were calculated from both laboratory percolation experiments and in situ piezometric measurements. Conclusions concerning Boom clay anisotropy are drawn. Finally, a short description of the ongoing in situ HTO injection experiment is given and the experimental data are analyzed and discussed. 10 refs., 4 figs., 1 tab

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

    Directory of Open Access Journals (Sweden)

    Rosas-Camacho O.

    2011-04-01

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

  17. Advection of an alkaline fluid through boom clay cores: geochemical modelling of experimental data

    International Nuclear Information System (INIS)

    As part of the ECOCLAY II project, with the financial support of NIRAS-ONDRAF and the European Commission, SCK-CEN has carried out experiments on the percolation of alkaline cement waters through Boom Clay cores. The effluent from these percolation experiments has been analysed as a function of time to provide information about the fluid-rock interactions occurring in the samples. However, the changes in the effluent composition with time are quite complex and require interpretation if insight is to be gained into the mechanisms of the interactions occurring in the samples between the invading alkaline fluid and the Boom Clay. Two cementitious waters were used in the experiments: a high pH (∼ 13,5) young cement water (YCW ) representing the initial eluate from a cement, and a lower pH (∼ 12) evolved cement water (ECW) representing the fluids that would emerge from the cements after long times. These fluids were passed through Boom Clay cores over several years and the composition of the effluent fluid monitored. The primary purpose of the modelling work was to provide an explanation of the processes controlling the interactions between the alkaline fluids and the Boom Clay. Four mechanisms were considered: the maintenance of the dissolution-precipitation thermodynamic equilibrium between the minerals and the pore fluids, ion exchange, kinetically controlled dissolution of primary minerals, and the functional group capacity of organic matter as a function of pH. The modelling was carried out using three essentially independent geochemical modelling packages: PHREEQC [Parkhurst and Apello, 1999] (Serco Assurance), PRECIP [Noy, 1990] (British Geological Survey) and CRUNCH [Steefel, 2001] (SCK-CEN). However, the general approach was similar in the three cases. Overall, this work has shown that it is possible to model the experiments to reproduce the main features seen on the correct time scales using simple models of plausible mechanisms. Similar conclusions have

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

    Science.gov (United States)

    MacDonald, D. D.; Saleh, A.; Lee, S. K.; Azizi, O.; Rosas-Camacho, O.; Al-Marzooqi, A.; Taylor, M.

    2011-04-01

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

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

    International Nuclear Information System (INIS)

    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

  20. Investigating the time-dependent behaviour of Boom clay under thermo-mechanical loading

    CERN Document Server

    Cui, Yu-Jun; Tang, Anh-Minh; Delage, Pierre; Li, Xiang-Ling; 10.1680/geot.2009.59.4.319

    2009-01-01

    Among the various laboratory studies to investigate the Thermo-Hydro-Mechanical (THM) behaviour of Boom clay, relatively few were devoted to the time dependent behaviour, limiting any relevant analysis of the long-term behaviour of the disposal facility. The present work aims at investigating the time-dependent behaviour of Boom clay under both thermal and mechanical loading. High-pressure triaxial tests at controlled temperatures were carried out for this purpose. The tests started with constant-rate thermal and/or mechanical consolidation and ended with isobar heating and/or isothermal compression at a constant stress rate or by step loading. Significant effects of temperature as well as of compression and heating rates were observed on the volume change behaviour. After being loaded to a stress lower than the pre-consolidation pressure (5 MPa) at a low temperature of 25\\degree C and at a rate lower than 0.2 kPa/min, the sample volume changes seemed to be quite small, suggesting a full dissipation of pore w...

  1. Modelling of natural organic matter-linked radionuclide transport in Boom clay

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In the framework of the Belgian research program on long term management of high-level and/or long-lived radioactive wastes coordinated by ONDRAF/NIRAS, Boom Clay is investigated for its potential to host a deep geological disposal repository. In order to demonstrate the suitability of the Boom Clay as a host rock, the mobility of critical radionuclides in this clay layer has been the subject of research during many years. As actinides, lanthanides and transition metals are known to form strong complexes with organic substances, the influence of the Natural Organic Matter (NOM) present in Boom Clay on the mobility of these critical radionuclides is of crucial importance. Interaction of radionuclides with OM present in Boom Clay could on the one hand retard the migration due to complexation/colloid interaction with the immobile OM, and on the other hand the mobility and solubility of the radionuclide can be enhanced by the formation of complexes/colloids with the mobile OM. The conceptual understanding (and its numerical modelling) of the kinetic stability and transport of these complexes/colloids is therefore regarded as highly important for the the long-term safety assesment of the geological disposal. This can be broken down into two subproblems: 1. Describing the transport behaviour of mobile OM in Boom Clay; 2. Describing the interaction of RN with mobile OM and the transport behaviour of the resulting complexes in Boom Clay. The first part of this paper revolves around the first subproblem, where a robust model for the description of the migration behaviour of Natural Organic Matter (NOM) is derived based on data from column migration experiments using 14C-labelled NOM Tracer solution, obtained in the framework of the EC TRANCOM-II project. Clay plugs of different lengths and different Darcy velocities were used. Inverse modelling with the MATLAB and COMSOL numerical code was done in order to identify the most

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

    International Nuclear Information System (INIS)

    Document available in extended abstract form only, full text follows: 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 rock-salt formations. TNO Geological Survey of the Netherlands has been granted two projects that deal with the geo-scientific characterisation of the Tertiary Boom Clay in the Netherlands, one of which is in cooperation with Utrecht University. The set-up of these projects is presented. The Boom Clay is the clay member of the Oligocene, marine Rupel Formation. Its official Dutch geological name is Rupel Clay member. The Boom Clay lies close to the surface in the southwestern and eastern margin of the Netherlands and its top lies at about 800 m below sea level in the northwestern corner of the Dutch mainland. The thickness varies from less than 50 m to over 200 m. In the first project, TNO will determine the present geological and geohydrological characteristics and features of the Boom Clay and of the geological environment enclosing the proposed host-rock. Based on an inventory of relevant literature references, existing map data, additional well data and recent seismic interpretations, we will determine the present regional scale geometry (depth and thickness maps) and past geodynamics of the Boom Clay and its hydro-stratigraphical overburden. This modelling stage will be followed by both lithological and geohydrological characterisation of the Boom Clay and its overburden, resulting in an assessment of lithological variation, an assessment of geohydrological properties, pressure gradients and the potential of existing overpressures within the Boom Clay and within the hydro-stratigraphical units of the overburden. In the second project, TNO and UU will characterise the sediment-geochemical properties as well as the groundwater composition above and below the Boom Clay. Insight into the geochemical

  3. A critical review of laboratory and in-situ hydraulic conductivity measurements for the Boom Clay in Belgium

    OpenAIRE

    Yu, Li; Rogiers, Bart; Gedeon, Matej; Marivoet, Jan; De Craen, Mieke; Mallants, Dirk

    2013-01-01

    The Boom Clay has been investigated for more than 30 years as a candidate host formation for the disposal of high-level and long-lived radioactive waste in Belgium. The very low hydraulic conductivity (on the order of 10− 12 m/s) in combination with limited hydraulic gradients over the host formation (0.02–0.04) results in water flow in the Boom Formation being negligible and diffusion the dominant transport mechanism. The assessment of the long-term barrier function of the host clay formatio...

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

    International Nuclear Information System (INIS)

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

  5. Early CO2 and polar liquid production from the boom clay kerogen upon thermal stress in relation with waste disposal

    International Nuclear Information System (INIS)

    Substantial amounts of organic matter (OM) ranging from ca. I to 5 wt% (average content of ca. 3 wt%) occur in the Boom Clay. Global examination showed that the Boom Clay contains low maturity type II kerogen (as commonly observed in immature sedimentary rocks the kerogen accounts for the bulk of the total OM of the clay) and this kerogen (isolated from a clay core stored and processed under strict anaerobic conditions) exhibits an especially high oxygen content. Based on such features, the Boom Clay kerogen should be prone to generate large amounts of liquid and gaseous compounds, including hetero-atomic compounds, upon thermal stress. Indeed, preliminary experiments showed the production, under a relatively moderate thermal stress of a variety of polar oxygen-containing compounds. The aim of the present study was to derive detailed molecular and kinetic information on the production of liquid and gaseous compounds, upon the type of thermal stress that the near field clay would undergo during disposal of high activity waste. Emphasis was put on low molecular weight oxygen-containing components. Indeed, the latter may influence the confinement properties of the clay barrier and the radionuclide transport through various processes like changes in PCO2, in pH, in complexation ability and in microbial growth in relation with changes in OM availability. (authors)

  6. The investigation of the neptunium complexes formed upon interaction of high level waste glass and boom clay media

    International Nuclear Information System (INIS)

    Since complexes formed between actinides released from high level waste glass and humic acids present in high concentration in boom clay porewater may control the actinide solubility in the clay formation, a research programme has been started to study the complexes formed between neptunium, the most critical actinide in the Belgian performance assessment studies, and boom clay porewater. The leaching experiments give a maximum solution concentration of Np in boom clay porewater of 10-6 M after 24 days. In the leachates, Np is mainly associated with colloidal particles of small sizes and is present as a mixture of two oxidation states, V and IV. The retention of Np in the glass increases with increasing SA/V (geometrical surface area on solution volume ratio). A high solution concentration is accompanied by a high retention of Np. The characterisation of the mobile boom clay organic matter (OM) gives a proton exchange capacity (PEC) equal to 2.9 meq g-1 OM at pH 8.5. Related to this value, the interaction constants (β) of the literature were reviewed and calculated according to their proton exchange capacity for the pH of interest. (orig.)

  7. Development of a thermodynamic sorption model for Boom Clay - The case of trivalent radionuclides

    International Nuclear Information System (INIS)

    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 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. Therefore, the quantification of the retardation and the elucidation of its underlying processes are indispensable for the demonstration of confidence (both scientifically and socio-politically) in the host formation to act as a suitable barrier. However, this is not an easy task, given the multitude of mineral/colloidal phases, chemical equilibria and kinetically driven processes involved. In this presentation, we will focus on the aspects of trivalent lanthanide (Ln)/actinide (An) sorption in Boom Clay batch suspensions under geochemical conditions relevant for the Mol-Dessel region (Belgium) to demonstrate the above mentioned complexity. The aim of this investigation is to explain experimentally observed solid-liquid distribution coefficients (Kd values) in terms of the major mechanisms that dictate the aqueous and solid phase speciation of such radionuclides. More specifically, we will present the most recent improvements in understanding and modelling of sorption in such suspensions starting from a 'bottom-up' (or component additivity (Davis et al., 1998)) approach. In this approach, the geo-matrix of the Boom Clay is dismantled into its main components that are deemed responsible for dictating the solid-liquid distribution of trivalent Ln/An. Several components were identified: illite and smectite clay minerals, solid organic matter (kerogen), carbonates and dissolved organic matter. The sorption or uptake mechanisms of trivalent Ln/An on these components are quite different in nature and include ion

  8. Quantifying the transferability of hydraulic parameters using Geostatistics: the Boom clay case

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Full text of publication follows: The Boom Clay is currently investigated as potential host formation for the deep disposal of high-level and/ or long-lived radioactive waste in Belgium. Deep disposal safety relies on multiple barriers: the 'supercontainer' containing the vitrified waste, the repository itself and the host formation in which the disposal could be constructed. The latter is the most important as it is the one that has to slow the migration of radionuclides towards the biosphere for a sufficiently long time when the man-made barriers are no longer effective. So it is the site's geology that must ensure that the long-term radiological impact of the waste in the repository stays below the nationally and internationally allowable limits and is therefore significantly lower than natural radioactivity. The Boom Clay is a marine Oligocene clay of approximately 100 m thick deposited in the North Sea basin. It is known in Germany, The Netherlands and Belgium as a continuous layer gently dipping (∼ 1 deg.) towards the north-north-east but also gaining thickness in this direction. One of the most remarkable characteristics of the Boom Clay is its structure of bands that are several tens of centimeters thick, reflecting mainly cyclical variations in grain size (silt and clay content). The Boom Clay aquitard requires to be precisely characterized in terms of hydrogeological parameters, to confirm its role of geological barrier between its surrounding aquifers. Therefore, hydraulic conductivity and diffusion parameters have been intensively measured at only a few boreholes in Belgium, mainly located in the Mol-Dessel area, assuming a good lateral continuity of the geology. This assumption needs to be validated by quantifying the transferability of the hydraulic parameters from well sampled to scarcely covered areas. Combining core measurements with more densely acquired geophysical information

  9. Chemical durability of vitrified high-level waste and spent fuel under simulated repository conditions of a Boom Clay formation

    International Nuclear Information System (INIS)

    The Belgian programme is considering both the closed and open fuel cycle options. In the closed cycle, HLW glasses from the former Eurochemic reprocessing plant and from the French R7T7 plants are studied. R and D is focused on the interaction with the Boom Clay disposal host and potential near field environments. In surface laboratory testing we developed new set-ups to investigate various coupled processes: (1) combined glass leaching/Si diffusion in clay, (2) diffusion/sorption/precipitation of Si in clay, (3) effect of the presaturation of clay with Si, and (4) the mobile concentrations of e.g. Np, Tc, Se in clay slurries after leaching from glass. In the CORALUS in situ test, we installed four tubes in the underground laboratory (SCK-CEN site), and retrieved two of them after an interaction time of ∼1 year (90 deg. C) and ∼3 years (30 deg C). The R and D on the geological disposal of spent fuel in Boom Clay is focused on two major issues: (1) study the effect of α-activity on the dissolution of α-doped UO2 (simulating spent fuel ages between 150 and 90000 years), and (2) study the influence of Boom Clay and potential backfill materials (apatite, cement, sand) on the α-doped UO2 dissolution rate. Different experimental set-ups have been elaborated. Flowthrough tests in clay water and static tests in clay slurries were carried out in reducing conditions. We report the main results obtained on both HLW glass and doped UO2. Both HLW glass and UO2 show a similar evolution of the dissolution behaviour with time in the clay containing media. After an initial relatively fast dissolution characterized by sorption onto the clay, a much lower dissolution rate is observed. For both waste forms this results in expected lifetimes during geological disposal of 105 years or more. (author)

  10. 99technetium speciation and pathways under boom clay reducing conditions when starting form different initial conditions

    International Nuclear Information System (INIS)

    Full text of publication follows: 99Technetium (Tc) is a redox-sensitive fission product whose geochemical behaviour in Boom Clay was intensively studied during the last years [1, 2]. However, several questions remain concerning the in situ migration behaviour of Tc in reducing sediments that are rich in humic substances (HS). When adding technetium as TcVIIO4- in concentrations in the range of 10-7 - 10-4 mol/L to Boom Clay suspension batches, it was observed that the added TcVII was reduced to TcIV according to XANES data [2]. However, the thermodynamically predicted TcO2 precipitate was not formed: (1) the concentration of Tc remaining in solution after reaction with the solid phase increases with the total amount of Tc added and (2) dissolved Tc concentrations were orders of magnitude above the predicted Tc solubility. This observation could be explained and described by a hydrophobic sorption mechanism of neutral Tc species on dissolved Boom Clay HS with a constant K-value [1]. The neutral Tc species were identified as TcIV Eigen-colloids - polymeric chains of TcO(OH)2 - by EXAFS measurements [2]. Moreover, batch (ir)reversibility experiments and column migration experiments starting out from the Tc-humic substance mixed colloids showed that the interaction is to a large extent irreversible, or at least kinetically favoured, thus precluding the adsorption of TcIV on the solid phase or the precipitation of a TcO2 phase. When adding technetium as a precipitated TcO2 phase, i.e. starting from conditions of under-saturation, to systems containing Boom Clay HS, the observed geochemical behaviour is dramatically different than the pathway outlined above. If TcIV precipitates are made starting from TcVII and using H4N2 as a reductant, an amorphous solid phase which is loosely bound and consists mainly of colloidal aggregates, is observed to be formed. Its solubility in synthetic (inorganic) groundwater is generally higher than the expected theoretical solubility of

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

    International Nuclear Information System (INIS)

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

  12. Conceptual model analysis of interaction at a concrete-Boom Clay interface

    Science.gov (United States)

    Liu, Sanheng; Jacques, Diederik; Govaerts, Joan; Wang, Lian

    In many concepts for deep disposal of high-level radioactive waste, cementitious materials are used in the engineered barriers. For example, in Belgium the engineered barrier system is based on a considerable amount of cementitious materials as buffer and backfill in the so-called supercontainer embedded in the hosting geological formation. A potential hosting formation is Boom Clay. Insight in the interaction between the high-pH pore water of the cementitious materials and neutral-pH Boom Clay pore water is required. Two problems are quite common for modeling of such a system. The first one is the computational cost due to the long timescale model assessments envisaged for the deep disposal system. Also a very fine grid (in sub-millimeter), especially at interfaces has to be used in order to accurately predict the evolution of the system. The second one is whether to use equilibrium or kinetic reaction models. The objectives of this paper are twofold. First, we develop an efficient coupled reactive transport code for this diffusion-dominated system by making full use of multi-processors/cores computers. Second, we investigate how sensitive the system is to chemical reaction models especially when pore clogging due to mineral precipitation is considered within the cementitious system. To do this, we selected two portlandite dissolution models, i.e., equilibrium (fastest) and diffusion-controlled model with precipitation of a calcite layer around portlandite particles (diffusion-controlled dissolution). The results show that with shrinking core model portlandite dissolution and calcite precipitation are much slower than with the equilibrium model. Also diffusion-controlled dissolution smooths out dissolution fronts compared to the equilibrium model. However, only a slight difference with respect to the clogging time can be found even though we use a very small diffusion coefficient (10-20 m2/s) in the precipitated calcite layer.

  13. Measuring the effective diffusion coefficient of dissolved hydrogen in saturated Boom Clay

    International Nuclear Information System (INIS)

    Highlights: • Experiments with H2 are often disturbed by micro organisms. • A complex sterilisation procedure was developed. • Heat sterilisation, gamma irradiation and the use of a microbial inhibitor were combined. • 3 reliable H2 diffusion coefficients were obtained. - Abstract: Boom Clay is studied as a potential host formation for the disposal of high-and intermediate level long-lived radioactive waste in Belgium. In such a geological repository, generation of gases (mainly H2 from anaerobic corrosion) will be unavoidable. In order to make a good evaluation of the balance between gas generation vs. gas dissipation for a particular waste form and/or disposal concept, good estimates for gas diffusion coefficients of dissolved gases are essential. In order to obtain an accurate diffusion coefficient for dissolved hydrogen in saturated Boom Clay, diffusion experiments were performed with a recently developed through-diffusion set-up for dissolved gases. Due to microbial activity in the test set-up, conversion of hydrogen into methane was observed within several experiments. A complex sterilisation procedure was therefore developed in order to eliminate microbiological disturbances. Only by a combination of heat sterilisation, gamma irradiation and the use of a microbial inhibitor, reliable, reproducible and accurate H2(g) diffusion coefficients (measured at 21 °C) for samples oriented parallel (Deff = 7.25 × 10−10 m2/s and Deff = 5.51 × 10−10 m2/s) and perpendicular (Deff = 2.64 × 10−10 m2/s) to the bedding plane were obtained

  14. The role of natural organic matter in the migration behaviour of americium in the Boom Clay - Part 1: migration experiments

    International Nuclear Information System (INIS)

    Full text of publication follows: In demonstrating the suitability of Boom Clay as reference site for studying the disposal of radioactive waste, the role of the relatively high amount of Natural Organic Matter (NOM) present in the Boom Clay on the mobility of critical radionuclides needs to be investigated thoroughly. It is generally accepted that trivalent actinides and lanthanides form strong complexes with humic substances. Complexation of these trivalent radionuclides with NOM present in the Boom Clay may therefore have two opposite effects. If complexed by the aqueous phase NOM (the mobile NOM), the radionuclide transport will be governed by the mobility of these dissolved radionuclide- NOM species. If complexed by the solid phase NOM (the immobile NOM) the 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 in order to develop a conceptual model for inclusion in a performance assessment (PA) model. The migration behaviour of Americium (used as an analogue for the critical radionuclide Pu) was investigated by complexing 241Am with radiolabelled (14C-labelled) NOM before passing through undisturbed Boom Clay cores contained in columns. The use of two different radionuclides, allows the migration behaviour of both the NOM and the Am to be followed. The results of the migration experiments showed that the Am-NOM complexes dissociated when they came into contact with Boom Clay and that the bulk of Am became immobilised (either as Am complexed to immobile NOM or sorbed to the mineral phase). Only a small percentage of the complex persisted as 'stabilised' Am-OM complex which exhibited slow dissociation kinetics upon moving through the Boom Clay. When the applied radionuclide source also contains Am in the form of an inorganic solid phase (when Am is applied above the solubility limit), a continuous source of Am exists to form 'temporarily stabilised' Am

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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)

  19. The effect of high pH alkaline solutions on the mineral stability of the Boom Clay - Batch experiments at 60 deg. C

    International Nuclear Information System (INIS)

    Boom Clay is currently viewed as a reference host formation for studies on deep geological disposal of radioactive waste in Belgium. The interactions between bulk rock Boom Clay and 0.1 M KOH, 0.1 M NaOH, 0.1 M Ca(OH)2, young cement water and evolved cement water solutions, ranging in pH from 12.5 to 13.2, were examined as static batch experiments at 60 deg. C to simulate alkaline plume perturbations, which are expected to occur in the repository due to the presence of concrete. Both liquids and solids were investigated at specific times between 90 and 510 days in order to control the elemental budget and to search for potential mineralogical alterations. Also, the clay fraction was separated from the whole-rock Boom Clay at the end of each run and characterized for its mineralogical composition. Thereby, the importance of the mineral matrix to buffer the alkaline attack and the role of organic matter to protect clay minerals were also addressed. The results indicate that the degree of geochemical perturbation in Boom Clay is dependent on the initial pH of the applied solution together with the nature of the major cation in the reactant fluids. The higher the initial pH of the media, the stronger its interaction with Boom Clay. No major non-clay mineralogical alteration of the Boom Clay was detected, but dissolution of kaolinite, smectite and illite occurred within the studied experimental conditions. The dissolution of clays is accompanied by the decrease in the layer charge, followed by a decrease in the cation-exchange capacity. The highest TOC values coincide with the highest total elemental concentrations in the leachates, and correspondingly, the highest dissolution degree. However, no quantitative link could be established between the degree of organic matter decomposition and clay dissolution.

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

    International Nuclear Information System (INIS)

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

  1. Assessment of the combined effects of temperature increase, water convection, migration of radionuclides, and radiolysis on the safety of nuclear waste repository in the Boom clay

    International Nuclear Information System (INIS)

    For a potential repository in the Boom clay formation at 220 m beneath the nuclear research center at Mol, Belgium, extensive temperature calculations have been done for several repository configurations. Taking into account, near field and far field temperature limitations, an acceptable heat load of 2.5 w/m2, and a cooling time of 50 years prior to disposal, have been derived. Hydrological phenomena in the water tables surrounding the Boom clay layer have been studied by installing a piezometric observation network over a surface of 2500 km2. A mathematical model has been developed to tern and the water transfer through the low impermeability clay layer. Verification of these results has been attempted by dating of the groundwaters and the interstitial clay water. A unidirectional analytical model has been developed that takes into account radioactive decay and water convection by a pressure gradient and assumes concentration equilibrium between the mobile and the stagnant fraction of the liquid phase

  2. Hydraulic characterization of the boom clay formation from the HADES underground laboratory in Mol: evolution and assessment of the piezometric techniques

    International Nuclear Information System (INIS)

    The network of piezometers installed in the Boom clay formation from the HADES Underground laboratory (-223 m) at Mol is an invaluable tool for the measurement and physical understanding of the groundwater flow towards a non closes deep repository system in an argillaceous formation. The hydraulic testing, test interpretation and groundwater sampling methodologies in a plastic clay (19 - 26 % H2O) at medium depth are presented. The results obtained from in situ tests (metric to local scale, 1 to 30 m) and from laboratory experiments on vertical and horizontal clay plugs (centimetric scale, 3 - 7 cm) have put into evidence the anisotropy of the Boom clay. The horizontal hydraulic conductivity is approximately 2.4 times higher than the vertical one. Laboratory and in situ results are discussed. Their comparison gives coherent hydraulic and transport parameters supporting the model used to describe quantitatively the migration of radionuclides through the clay. Meanwhile, concerning the hydraulic conductivity, a large discrepancy still subsists with the regional model (kilometric scale, 40 km x 80 km) which is presently being revisited (i.a. boundary conditions and refinement of the mesh, from 5 to 0.5 km) and with the regional observations often too scarce (water level measurements in the sandy aquifers surrounding the Boom clay formation). (authors). 8 refs., 2 figs., 1 tab

  3. Coupled thermo-hydro-bio-geochemical reactive transport model of CERBERUS heating and radiation experiment in Boom clay

    International Nuclear Information System (INIS)

    Final disposal of high-level radioactive waste in deep repositories in clay formations is being considered by several countries. Repository safety assessment requires the use of numerical models of groundwater flow, solute transport and chemical processes. These models are being developed from data and knowledge gained from in situ experiments such as the CERBERUS experiment carried out at the HADES facility excavated in the Boom clay formation at Mol (Belgium). This long-term experiment is aimed at evaluating the effect of heating and radiation in Boom clay. The test was performed in a cased well drilled at 223 m depth and lasted from 1989 to 1994. A 60Co source of 400 TBq and two heaters were emplaced inside the well. Dose rate, temperature, porewater pressure and pH/Eh were measured in situ during the experiment and gas and porewater samples were taken for chemical analyses. Here a coupled thermo-hydro-geochemical (THC) model of the CERBERUS experiment is presented which accounts simultaneously for heating, radiation, solute diffusion and a suite of geochemical reactions including: aqueous complexation, acid-base, redox, mineral dissolution/precipitation, cation exchange and gas dissolution/ex-solution. Computed results indicate that heating and radiation causes a slight oxidation, a decrease in pH, slight changes in porewater chemistry and pyrite dissolution near the well. THC model results follow the general evolution of chemical data, but cannot fit SO4 data. Model discrepancies are partly overcome when microbially-mediated Fe and SO4 reduction are taken into account in a coupled thermo-hydro-bio-geochemical (THBC) model. This THBC model captures the trends of geochemical data, improves the fit to dissolved SO4 and predicts pyrite precipitation, a process observed near the CERBERUS well. The ability of the THBC numerical model to reproduce the overall trends of geochemical data of the CERBERUS experiment provides confidence in such a model as a suitable tool

  4. 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)

    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 241Am-14C-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 14C-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 241Am-14C-NOM migration experiments. The stability properties of the 241Am-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 241Am-OM is the most stable, and that this sub

  5. CORALUS phase II. Gas release and migration in the boom clay of mol within the project 'Corrosion of Active Glass in the Underground conditions'

    International Nuclear Information System (INIS)

    Within the scope of national and international radioactive waste disposal concepts, the intention is to isolate them in deep geological formations in order to avoid the release of radionuclides into the biosphere above an acceptable limit. Besides salt and granite, clay formations are investigated. For investigating the suitability of clay formations in terms of their physical and chemical behaviour, the Belgian research centre SCK-CEN is performing an in situ test called CORALUS (CORrosion of Active gLass in Underground Storage conditions) in the Boom clay of the Underground Research Facility HADES in Mol /VAL 97/. The overall objective of the CORALUS project is to study the performance of both active and inactive HLW glass specimens in direct contact with different types of backfill materials under conditions as representative as possible for those expected to prevail in a disposal site in the Boom clay formation (α- and γ-irradiation, temperature, pressure, backfill material, formation water,..). The experimental set-up represents a scenario in which the vitrified waste comes into direct contact with the interacting backfill material and/or the Boom clay. (orig.)

  6. Gas release and migration in the boom clay of mol within the project 'Corrosion of Active Glass in the Underground conditions' (CORALUS)

    International Nuclear Information System (INIS)

    Within the scope of national and international radioactive waste disposal concepts, the intention is to dispose of radioactive waste in deep geological formations, in order to isolate them from the biosphere and avoid the release of radionuclides above an acceptable limit. Besides salt and granite, clay formations are investigated. For investigating the suitability of clay formations in terms of their physical and chemical behaviour, the Belgian research centre SCK-CEN is performing an in situ test called CORALUS (CORrosion of Active gLass in Underground Storage conditions) in the Boom clay of the Underground Research Facility HADES in Mol/VAL 97/. The overall objective of the CORALUS project is to study the performance of both active and inactive HLW glass specimens in direct contact with different types of backfill materials under conditions as representative as possible for those expected to prevail in a disposal site in the Boom clay formation (α- and γ-irradiation, temperature, pressure, backfill material, formation water,..). The experimental set-up represents a scenario in which the vitrified waste comes into direct contact with the interacting backfill material and/or the Boom clay, because of the occurrence of fissures in the waste canisters and the metallic overpack. (orig.)

  7. 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)

    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 129I. (author)

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

    International Nuclear Information System (INIS)

    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 13C 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

  9. Alteration of the molecular-size-distribution of Boom Clay dissolved organic matter induced by Na(+) and Ca(2.).

    Science.gov (United States)

    Durce, D; Maes, N; Bruggeman, C; Van Ravestyn, L

    2016-01-01

    In porous media, the extent of dissolved organic matter (DOM)-facilitated contaminant transport depends on the concentration, conformation and the size of the dissolved organic species. Yet, these parameters are highly sensitive to the ionic strength (IS) and the ionic composition of the solution. Boom Clay (BC) which is considered in Belgium as a potential host rock for nuclear waste disposal contains polydisperse DOM that might associate with radionuclide and increase their mobility. To get more insight into the effect of IS on DOM structure and into its impact on the solid/solution partitioning of OM in BC is essential for safety assessment. In a first set, we investigated the influence of NaCl and CaCl2 content on the concentration, the MW distribution and UV spectral parameters of DOM collected from BC. With an increase in IS two main mechanisms were identified: a compaction and/or dissociation of the DOM molecules and an aggregation. We showed that the sensitivity of the DOM species to these two mechanisms was size/MW dependent and that the presence of Ca(2+) promotes the aggregation. The largest species are more prone to aggregation which at the extreme leads to their transfer to particulate OM. On the contrary, small DOM species hardly aggregate but compact or dissociate with an increase of IS. These observations were confirmed in the second experimental set in which we followed the release of DOM from BC rock in various electrolytes. The increase of IS and multivalent cations content reduces the amount, the degree of aromaticity and the MW of DOM released from BC which limit the extent of DOM-facilitated contaminant transport in BC. PMID:26788872

  10. Alteration of the molecular-size-distribution of Boom Clay dissolved organic matter induced by Na+ and Ca2 +

    Science.gov (United States)

    Durce, D.; Maes, N.; Bruggeman, C.; Van Ravestyn, L.

    2016-02-01

    In porous media, the extent of dissolved organic matter (DOM)-facilitated contaminant transport depends on the concentration, conformation and the size of the dissolved organic species. Yet, these parameters are highly sensitive to the ionic strength (IS) and the ionic composition of the solution. Boom Clay (BC) which is considered in Belgium as a potential host rock for nuclear waste disposal contains polydisperse DOM that might associate with radionuclide and increase their mobility. To get more insight into the effect of IS on DOM structure and into its impact on the solid/solution partitioning of OM in BC is essential for safety assessment. In a first set, we investigated the influence of NaCl and CaCl2 content on the concentration, the MW distribution and UV spectral parameters of DOM collected from BC. With an increase in IS two main mechanisms were identified: a compaction and/or dissociation of the DOM molecules and an aggregation. We showed that the sensitivity of the DOM species to these two mechanisms was size/MW dependent and that the presence of Ca2 + promotes the aggregation. The largest species are more prone to aggregation which at the extreme leads to their transfer to particulate OM. On the contrary, small DOM species hardly aggregate but compact or dissociate with an increase of IS. These observations were confirmed in the second experimental set in which we followed the release of DOM from BC rock in various electrolytes. The increase of IS and multivalent cations content reduces the amount, the degree of aromaticity and the MW of DOM released from BC which limit the extent of DOM-facilitated contaminant transport in BC.

  11. 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)

    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 NaNO3, 20-30 wt%, and CaSO4, 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. NaNO3 or NaNO2, 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 NaNO3, or 0.05 and 0.005 M NaNO2. 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 solutions and of

  12. 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)

    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)

  13. In situ and laboratory investigation of the alteration of Boom Clay (Oligocene) at the air–geological barrier interface within the Mol underground facility (Belgium): Consequences on kerogen and bitumen compositions

    International Nuclear Information System (INIS)

    The Boom Clay formation (Oligocene) is studied as a reference host rock for methodological studies on deep geological disposal of radioactive waste. During excavation of galleries within the Clay formation (HADES underground research facility, Mol, Belgium), the physico-chemical conditions are significantly modified as an air–clay interface is created. In order to study the long-term impact of the air–clay contact on the organic matter contained in the Boom Clay, two types of samples were studied: (1) a reference series of clay samples having been in contact with the atmosphere of the HADES gallery for increasing times up to several years and (2) unaltered clay samples submitted to artificial oxidation in a ventilated oven at 80 °C. The evolution of geochemical data of the two series was compared using Rock-Eval pyrolysis, GC–MS and size exclusion chromatography. The organic matter of the unaltered clays sampled in the HADES galleries is dominated by type III kerogen (terrestrial) with some contribution of type II (marine) and is thermally immature. The evolution of geochemical parameters during air alteration for the two series are very similar. They show progressive oxidation of kerogen accompanied by the release of bitumen enriched in low molecular weight constituents. Molecular analysis evidences the presence of a complex mixture of aliphatic and aromatic O-bearing compounds, inherited from the degradation of kerogen as well as from the clay catalyzed oxidation of the bitumen. These results show that (1) air oxidation is a major process in the in situ alteration of the organic matter of Boom Clay within the HADES galleries, (2) laboratory oxidation experiments at 80 °C yield similar results as in situ air alteration of Boom Clay and (3) artificial air oxidation may be used to assess the long term exposure of the organic matter to air.

  14. The integration of geosphere data into a safety case - the example of the safety function ''diffusion and retention'' in the boom clay

    International Nuclear Information System (INIS)

    In Belgium, the Radioactive Waste Management Agency NIRAS/ONDRAF is considering the deep disposal of high level and long-lived radioactive waste in clay media as long-term management option. The SAFIR report dealt with the first phase of the methodological R and D programme in a view of establishing and increasing confidence in deep disposal. The methodological programme is focused on a reference formation and site, i.e. the Boom Clay beneath the nuclear zone in Mol-Dessel (NE Belgium), without making any presumptions on the site as site for the actual implementation. In 1990, the SAFIR Evaluation Commission stated that the focus of the programme on vitrified waste an don the Boom Clay in the vicinity of the Mol-Dessel nuclear zone was justified. However, the Commission suggested additional issues to consider in the next phase of the programme such as an alternative host formation, the Ypres Clays and the consideration of direct disposal of spent fuel. It also provided the basis for the 1990-2000 R and D programme. SAFIR 2 reports the results of this ten-year R and D programme in a view of obtaining a twofold governmental decision allowing (i) to continue the technical disposal programme and (ii) to open a societal dialogue with the various stakeholders on long-term waste management. SAFIR 2 is one step in the overall step-wise process for a repository in Belgium. Further development of the characterisation, assessment and implementation methodologies will be carried out focussing on the reference host formation and site and with the support of large-scale, integrated in situ experiments (PRACLAY). Instead of state-of-the-art reports (like SAFIR), ONDRAF/NIRAS envisages to collect all the arguments supporting the safety and the feasibility of the proposed disposal solution in a self-supporting document. A first Safety and Feasibility Case is planned by 2012. A 2. report would be available by 2020 and should provide all the necessary information to enter a site

  15. 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)

    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 85oC). Leach rates of seven radionuclides (60Co, 90Sr, 134Cs, 137Cs, 144Ce, 154Eu and 241Am) 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 SO4 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)

  16. Model validation based on in situ radionuclide migration tests in Boom clay: status of the CP1 experiment, 24 years after injection

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. The demonstration of the long-term safety of a nuclear waste repository relies heavily on earth science models, integrated in a total repository system safety assessment. It is important to demonstrate the validity of those models so that various stakeholders can have confidence in the safety assessment outcome. The models are therefore subject to quality assurance procedures of which model validation, qualification and verification are essential elements. However, it is acknowledged that in the context of repository safety assessment, model validation is often limited because of two reasons: i) the extreme timescale covered by the assessment and ii) the use of natural barriers, for which complete characterisation is impossible. Nowadays, validation is considered a confidence building process, aimed at demonstrating that the model is consistent with the scientific understanding and that it adequately represents the considered phenomena and interactions relevant to the assessment case. In this study, the validity of model and parameters is demonstrated for non-retarded radionuclide transport in Boom Clay, currently considered by Ondraf/Niras as a potential host formation for geological disposal of radioactive waste in Belgium. Performance assessment studies so far have shown that in the integrated system of engineered and natural barriers, the Boom Clay is the dominant barrier contributing to long-term radiological safety. Indeed, the very low hydraulic conductivity and absence of significant hydraulic gradients make diffusion the dominant radionuclide transport mechanism and most radionuclides are even further retarded in their transport due to various retardation processes on clay particles. Between 1980 and 1983, the HADES underground research facility was constructed at a depth of 223 m in the Boom Clay layer underneath the nuclear site in Mol (Belgium), in order to assess the feasibility of repository

  17. Interaction of selenite with iron sulphide minerals: implications for the geochemical fate of Se in Boom Clay

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. The geochemistry of selenium, exhibiting valence states from +VI to -II, is of key importance due to its role as a highly toxic essential micro-nutrient and as a significant component of high level radioactive waste (HLRW). XAS studies conducted at circum-neutral pH have shown that pyrite (FeS2), the most relevant redox-active mineral in Boom clay, reduces selenite to a solid-state Se(0) phase. This observation raises several questions. First, why does an Fe-free Se(0) phase in form presence of pyrite, while selenite is reduced to FeSex by troilite and mackinawite (FeS)? What is the exact identity of this elemental Se phase, which has been observed by several authors? Why is a dissolved, low oxidation-state selenium species encountered in association with the Se(0) phase; and what is its identity? Correlating selenium redox chemistry with sulphide mineral oxidation pathways allowed to link these observations to the different oxidation behaviour of acid-soluble and acid-insoluble metal sulphides. The end products of Se(IV) reduction by acid-soluble iron sulphur minerals are fairly well known, but the solid and liquid phase species present during interaction of SeO32- with pyrite are poorly characterized. The solid phase reaction product could not yet be assigned as a specific phase, but clearly identified as a Se0 compound. Trigonal (grey) selenium could be excluded as a candidate. Acid insoluble metal sulphides such as pyrite, molybdenite or tungstenite exhibit oxidative dissolution only. Upon six consequent one-electron oxidation steps, a thiosulphate anion is liberated (thiosulphate pathway). In contrast, acid soluble metal sulphides (troilite, mackinawite, sphalerite, etc.) exhibit also non-oxidative dissolution thereby liberating sulphide species (H2S, HS-,S2-). Under oxidative dissolution in presence of Fe-III, they release sulphide cations (e.g. H2S+). The latter can spontaneously dimerize into disulphide

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

    International Nuclear Information System (INIS)

    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.

  19. Updating of the performance assessments of the geological disposal of high-level and medium-level wastes in the Boom clay formation

    International Nuclear Information System (INIS)

    The objective of this report is to assess the performance of disposed medium-level and alpha-bearing waste in a geological repository in the Boom clay formation at the Mol site (Belgium). The results of this study are based on calculations that are in agreement with recent information on the Belgian nuclear programme and the corresponding waste arising. The applied methodology consists of two consecutive steps: (1) a scenario analysis in which relevant scenarios, leading to the exposure of man to radiation are selected, and (2) a consequence analysis in which potential radiological consequences of the exposure are evaluated. The scenario, selected in this study, is designated as the normal evolution scenario and comprises a normal evolution scenario in which the present conditions are assumed to last infinitely. The scenario is extended with a climatic change, a secondary glaciation effects, and a faulting scenario. The applied consequence analysis consists in deterministic and stochastic calculations, which are are complementary. Three pathways of radionuclides to man were considered: (1) the discharge of contaminated groundwater into rivers or (2) into agricultural soils, and (3) the sinking of a water well into the aquifer that overlies the host formation. Calculations indicate that most radionuclides decay within the first metres of the clay barrier. The fission and activation products 14C, 129I, 79Se, 99Tc, 107Pd, 93Zr, and 135Sr as well as some actinides of the 237Np and uranium decay series can however reach the biosphere. The maximum dose rates for high-level waste, fuel cladding, medium-level, and iodine waste were calculated. Deterministic calculations indicate that the maximum dose rates are attained via the water well pathway for the case of the climatic change scenario. (A.S.)

  20. 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)

    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 mm2, while the focused ion beam (FIB, 1 pA - 45 nA) is better used for fine and precise polished cross-sections area of about few μm2. 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

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

    Directory of Open Access Journals (Sweden)

    Wang Mingyi

    2016-01-01

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

  2. 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

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

    OpenAIRE

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

    2012-01-01

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

  4. Effects of mineralogy and grain-size distribution on pore space morphologies in Boom clay - Insights from 2D high resolution BIB-SEM investigations and mercury injection porosimetry

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Microstructures in Boom Clay samples from the ON-Mol-1 borehole ('Mol-Dessel research site', Belgium), with different grain-size distributions, were studied, using broad-ion beam (BIB) milling and secondary electron microscopy (SEM-imaging). Additionally Mercury injection Porosimetry (MIP) was used to correlate direct microstructural pore space insights with bulk sample porosity information. From BIB-SEM observations, overall Boom Clay fabrics can be described as a porous clay-matrix in which several low-porous, non-clay mineral (NCM) phases are embedded. Each different mineral phase shows its characteristic pore morphologies and visible 'intra-phase porosity', regardless of the depth of sample origin, mineralogical composition or grain-size distribution of the sample. From the detailed analysis of BIB-SEM segmented porosities, we found largest pores (> ∼1,000,000 nm2 pore area) to be concentrated around (big) non-clay mineral grains, with their median pore-sizes correlating with the sample grain-size; those so-called 'inter-phase pores' account for between 11-90 % of the total segmented porosities from BIB-SEM, with the amount increasing with the sample grain-size and non-clay mineral content. Total porosities detected at the scale of the SEM are between 10 to 15 % of the analyzed areas between 10,000 to 25,000 μm2 size. Pore-size distributions observed within the clay-matrices of samples are log-normal, showing a peak ∼1,000 nm2 pore area, but since the practical pore detection resolution is as well around that pore-size, we assume for pore-size distributions to be cut off at that point, due to the pore detection resolution, and to actually follow a power-law distribution. Fitting pore-size distributions within a range from ∼1,000 to 1,000,000 nm2 pore area, using power-laws, results in power-law exponents between 1.55-1.66. Assuming self-similarity of the pore space in Boom Clay, these power-laws were

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

    International Nuclear Information System (INIS)

    Long-term, sequential column migration experiments with Tc(IV), Cm(III), Np(IV), Pu(III/IV) and Pa(V) through Boom Clay cores were used to interpret the Organic Matter (OM) linked radionuclide (RN) transport. Based on observed processes, a consistent phenomenological model is proposed to describe the transport behaviour of the RN-OM linked species. The phenomenological model considers the radionuclide to be transported as an organic matter complex/colloid that slowly dissociates, and both the RN-OM and the RN sorb to the solid phase. Based on independently determined OM transport parameters and radionuclide-OM interaction constants, the model is well constrained and requires only 3 fitting parameters: the de-complexation constant, k decomp, and the retardation factors for both the RN and the RNOM species, RRN and RRNOM. The resulting fitted dissociation kinetics are found to be in a narrow range (0.3-1.7x10-6s-1), despite the difference in aqueous speciation. The fitted radionuclide retardation factors were found to be consistent with independent determined sorption data, which provides confidence in the conceptual model. The dissociation kinetics govern the transfer of RN mobilised by OM to RN sorbed on the solid phase and the kinetic de-complexation leads to an appreciable retardation of the colloid facilitated transport. This conceptual model is an important step forward in the description of OM linked RN transport in Boom Clay and it can be directly used for safety assessment analysis: (i) it is process based, (ii) the model is easy to implement without oversimplification and (iii) elements with a similar OM association behaviour can be described in the same way and the input parameters fall within a narrow range. (authors)

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

    OpenAIRE

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

    2006-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    2011-10-01

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

  9. Industrialisation of Easy Boom

    Directory of Open Access Journals (Sweden)

    M. Sokovic

    2011-02-01

    Full Text Available Purpose: Reason for writing the paper is to present the project of design and industrialization of floating containment boom made of PVC material, which was successfully finished in 2010. This project was supported by Savatech d.o.o. Kranj.Design/methodology/approach: Research methodology of floating containment boom made of PVC has focused on a comprehensive analysis of this type of booms, which are used around the world. Based on this knowledge and over 25 years of experiences with rubber booms, a new type of PVC boom was developed.Findings: The result of the project was the design and implementation of a new type of floating containment boom. The new boom is light weight, highly stable with no inflation system required. Boom has small volume when packed for transport and is simple and quick to deploy. It is made of UV and oil resistant material.Practical implications: The new type of oil boom was tested in clean water and is available for application in oil spill accidents. Also calculations for salt water were made. Boom is suitable for closed waters, rivers and streams, harbours, canals, etc.Originality/value: Product of research and development is an original Slovenian PVC floating containment boom marked as Easy Boom.

  10. Floating boom assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, J.D.

    1994-08-03

    A floating boom has associated means for injecting one or more flows of fluid (gas and/or liquid) adjacent an external surface of the boom. Such a flow may be arranged to rise up the side of the boom, staying close to it owing to the Coanda effect. This may serve to discourage a lighter liquid (e.g. oil) on the surface of the bulk liquid from passing under the boom and/or assist passage of the lighter liquid over a weir into a reservoir (which may be provided within the boom). (Author)

  11. Three dimensional analysis of the pore space in fine-grained Boom Clay, using BIB-SEM (broad-ion beam scanning electron microscopy), combined with FIB (focused ion-beam) serial cross-sectioning, pore network modeling and Wood's metal injection

    Science.gov (United States)

    Hemes, Susanne; Klaver, Jop; Desbois, Guillaume; Urai, Janos

    2014-05-01

    The Boom Clay is, besides the Ypresian clays, one of the potential host rock materials for radioactive waste disposal in Belgium (Gens et al., 2003; Van Marcke & Laenen, 2005; Verhoef et al., 2011). To access parameters, which are relevant for the diffusion controlled transport of radionuclides in the material, such as porosity, pore connectivity and permeability, it is crucial to characterize the pore space at high resolution (nm-scale) and in 3D. Focused-ion-beam (FIB) serial cross-sectioning in combination with high resolution scanning electron microscopy (SEM), pore network modeling, Wood's metal injection and broad-ion-beam (BIB) milling, constitute a superior set of methods to characterize the 3D pore space in fine-grained, clayey materials, down to the nm-scale resolution. In the present study, we identified characteristic 3D pore space morphologies, determined the 3D volume porosity of the material and applied pore network extraction modeling (Dong and Blunt, 2009), to access the connectivity of the pore space and to discriminate between pore bodies and pore throats. Moreover, we used Wood's metal injection (WMI) in combination with BIB-SEM imaging to assess the pore connectivity at a larger scale and even higher resolution. The FIB-SEM results show a highly (~ 90 %) interconnected pore space in Boom Clay, down to the resolution of ~ 3E+03 nm³ (voxel-size), with a total volume porosity of ~ 20 %. Pore morphologies of large (> 5E+08 nm³), highly interconnected pores are complex, with high surface area to volume ratios (shape factors G ~ 0.01), whereas small (areas (REAs) (Hemes et al., 2013).

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

    Science.gov (United States)

    Prebble, Warwick M.; Williams, Ann L.

    2016-06-01

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

  13. Echo Boom Impact

    Science.gov (United States)

    Dordai, Phillipe; Rizzo, Joseph

    2006-01-01

    Like their baby-boomer parents, the echo-boom generation is reshaping the college and university landscape. At 80 million strong, this group of children and young adults born between 1980 and 1995 now is flooding the college and university system, spurring a college building boom. According to Campus Space Crunch, a Hillier Architecture survey of…

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

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

    2016-11-01

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

  16. Beyond the Boom

    Institute of Scientific and Technical Information of China (English)

    ANDY XIE

    2006-01-01

    @@ Annual GDP growth has averaged 10 percent in China in the past three years and 8 percent in India. During the same period,the global economy has enjoyed the biggest boom in decades,averaging 4.5 percent growth a year.

  17. Boom Booom Net Radio

    DEFF Research Database (Denmark)

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

    1999-01-01

    Internet radio is one of the growth areas of the Internet but, as this article will show, is fraught with difficulties and frustration for both the modestly-funded broadcaster (bitcaster) and the listener. The article will illustrate some of these problems by means of a short case study...... 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....

  18. 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.

  19. Animation of boom failure processes

    International Nuclear Information System (INIS)

    Computer animations of oil boom failure mechanisms were discussed. The animations are useful in demonstrating the transient processes of boom failure. They consist of a series of images obtained from the graphical output of a computational fluid dynamics program, FLUENT, while the modeling is based on boom failure experiments carried out in flowing water channels. The animations can be viewed on a PC running under Windows '95. Three types of failures are presented, i. e. drainage failure, droplet entrainment and critical accumulation. 11 refs., 3 figs

  20. Loudness of shaped sonic booms

    Science.gov (United States)

    Shepherd, Kevin P.; Sullivan, Brenda M.

    1990-01-01

    A loudness model is adopted to study the feasibility of designing and operating a supersonic transport to produce minimized sonic booms. The loudness contours in this technique extend to a lower frequency (1 Hz) and thus are appropriate for sonic booms that contain significant low frequency energy. Input to the loudness calculation procedure is the power spectral density of the pressure-time signature. Calculations of loudness, for both indoor and outdoor conditions, demonstrate that shaped sonic booms are potentially more acceptable than N-waves possessing the same peak overpressure.

  1. NASA Ames Sonic Boom Testing

    Science.gov (United States)

    Durston, Donald A.; Kmak, Francis J.

    2009-01-01

    Multiple sonic boom wind tunnel models were tested in the NASA Ames Research Center 9-by 7-Foot Supersonic Wind Tunnel to reestablish related test techniques in this facility. The goal of the testing was to acquire higher fidelity sonic boom signatures with instrumentation that is significantly more sensitive than that used during previous wind tunnel entries and to compare old and new data from established models. Another objective was to perform tunnel-to-tunnel comparisons of data from a Gulfstream sonic boom model tested at the NASA Langley Research Center 4-foot by 4-foot Unitary Plan Wind Tunnel.

  2. Housing Booms and City Centers

    OpenAIRE

    Edward L. Glaeser; Joshua D. Gottlieb; Kristina Tobio

    2012-01-01

    Popular discussions often treat the great housing boom of the 1996-2006 period as if it were a national phenomenon with similar impacts across locales, but across metropolitan areas, price growth was dramatically higher in warmer, less educated cities with less initial density and higher initial housing values. Within metropolitan areas, price growth was faster in neighborhoods closer to the city center. The centralization of price growth during the boom was particularly dramatic in those met...

  3. Analysis of boom spreader mass

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, H.J.

    1983-03-01

    The paper investigates weight and size of large boom spreaders employed for overburden haulage in surface mining. Major steel parts of the upper spreader construction are set in relation to one another (main frame, spreading boom, counterbalance mass, boom of counter mass etc.); their mass is compared for 16 boom spreaders with haulage capacities ranging from 4,400 to 15,400 m/sup 3//h of overburden removal. A formula is derived for calculating the mass of the upper structure in relation to its capacity and boom length. The influence of total equipment ground pressure and the mass of the spreader undercarriage is further analyzed: a diagram is given for the undercarriage mass required to achieve the necessary load bearing capacity. In order to maintain ground pressure values, length and width of undercarriage crawler tracks can be varied. Series of two to twelve crawler track undercarriages are available. Optimum size and mass of undercarriages is shown by parameters of 6 TAKRAF undercarriages.

  4. 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...

  5. Repository tunnel construction in deep clay formations

    International Nuclear Information System (INIS)

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

  6. Alberta's new oil boom

    International Nuclear Information System (INIS)

    A massive expansion of Canada's oil sands and the oil-mining business is underway. The prediction is that within five years there will be at least three, possibly six, huge new open pit mines north of Fort McMurray, Alberta. It was suggested that within 20 years, possibly half of Canada's oil supply will come from the oil sands industry which has already attracted $10 billion worth of developments. Unlike conventional crude, the oil sands contain bitumen, water, clay, minerals and lots of sands. Shallow deposits are mined like coal. Deeper formations make use of in-situ thermal recovery techniques. Extraction costs are presently at $15 per barrel, aiming for $12 by 1999. Return on investment is in double digits. Estimates of reserves in the Athabasca, Cold Lake, Peace River and Wabasca deposits go as high as 1.7 trillion barrels, or about twice as much as Saudi Arabia's conventional crude reserves. Syncrude has built a $5 billion production facility and two pipelines have already been proposed to transport the oil sands crude to midwestern US refineries. US refineries prize synthetic crude as excellent mixing stock. The major problem with oil sands is that unlike conventional oil, these reserves require an enormous amount of energy to exploit, which in turn means lots of foul air and greenhouse gases. There are many environmental unknowns, and without a clear management framework in sight the addition of two or three Syncrude-size operations has the potential to create a real and significant acid rain problem in the Western Canada Basin

  7. 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).

  8. Waste disposal concept in a tertiary clay formation

    International Nuclear Information System (INIS)

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

  9. Debris booms for protection of spillways

    International Nuclear Information System (INIS)

    A description is included of concerns pertaining to the use of booms to protect spillways of dams from blockage by floating debris. A well designed and constructed debris boom, if properly maintained can help to protect spillways from blockage. For reservoirs with spillways which could be plugged by small amounts of debris, booms offer questionable protection because low floating wood can pass under even with low water velocity, and small debris can be washed over by wave action. The failure of a debris boom could cause spillway blockage. The strength of boom components can deteriorate rapidly and unpredictably because of various natural forces. For installations at high altitude, there must be time between ice breakup and and spilling to prevent damage if a boom is to be used. Boom design is very site specific. Debris consisting of whole trees with limbs exert very high forces. Debris inflow to a reservoir is difficult to predict on a long term basis. Booms will not stop the passage of all debris, and their effectiveness varies with the type of debris, and with weather and flood conditions. Aspects described include: boom types, boom loadings, location, durability, small dams, conclusions and recommendations. 2 refs., 11 figs

  10. Unstructured grids for sonic-boom analysis

    Science.gov (United States)

    Fouladi, Kamran

    1993-01-01

    A fast and efficient unstructured grid scheme is evaluated for sonic-boom applications. The scheme is used to predict the near-field pressure signatures of a body of revolution at several body lengths below the configuration, and those results are compared with experimental data. The introduction of the 'sonic-boom grid topology' to this scheme make it well suited for sonic-boom applications, thus providing an alternative to conventional multiblock structured grid schemes.

  11. 围油栏形状优化的数值模拟%Numerical simulation of oil booms shape optimization

    Institute of Scientific and Technical Information of China (English)

    魏芳; 许颖

    2011-01-01

    文中对传统围油栏进行形状优化,应用流体体积分数法(VOF),数值模拟优化后的围油栏对两种不同粘度油类拦油效果;通过分析、比较拦油失效速度、失效时间以及围油栏失效前的栏前受压,说明围油栏形状优化的可行性,以提高围油栏的拦油性能.%Floating booms is commonly used to hold back oil spill on water surface, while oil boom failure often occurs in cases of water currents with high velocity. In order to improve the performance of booms, firstly volume of fluid (VOF) method was applied to numerically simulate traditional booms, and then the optimization of oil boom was carried out by changing the structure and shape of booms. Through the analysis and comparison of the block oil failure speed, failure time and the pressure before boom failure, the numerical simulate results indicate that the optimization shape of oil booms are feasible to improve oil spill interceptions.

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

    International Nuclear Information System (INIS)

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

  13. 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.

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

    International Nuclear Information System (INIS)

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

  15. Community Response to an Oil Boom.

    Science.gov (United States)

    Copp, James H.

    A study of the process of a 1977-1983 oil and gas boom in Caldwell, Texas, disproved the assumption that local social effects of rapid energy development are severe and negative. Using interviews, surveys, observation, local newspapers, and other writings as data sources, researchers determined that during the boom, Caldwell's population grew…

  16. Water discharging over weir with installed boom

    Directory of Open Access Journals (Sweden)

    Kupriyanov Vladimir Pavlovich

    2014-03-01

    Full Text Available This paper considers a possibility of booms application at spillway dams in order to reduce gates size and capacity of weight lifting device without changing weir discharge capacity. The prospects of booms application at weir top were proved during hydraulic researches conducted at JSC “NIIES” (Joint Stock Company “Scientific Research Institute of Energy Structures”. Basing on the conducted researches the recommendations of booms application at spillway facilities of Yumaguzinskaya and Upper Krasnogorskaya hydropower schemes, as well as at spillway facilities of Sayano-Shushenskaya and Plyavinskaya hydropower plants have been worked out. The main factor limiting wide application of booms at weirs is lack of feasible data for designing. At first, this data has to conclude methods of defining spillway discharge capacity and elevation of boom installation, which allows to keep the same spillway discharge capacity at rated head. The equations to define optimal elevation of boom installation and weir discharge capacity without its submergence have been analytically obtained for nappe-crested weir with installed boom. At the present time it is needed to conduct methodical experimental studies to define the discharge ratio and vertical compression according to different types of booms.

  17. Experts: Chinese Economic Boom Against Global Slowdown

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    China economic boom to last until at least 2020"The cycle of economic boom in China, the world’s fastest-growing major economy, would last until at least 2020", said an expert with the National Development and Reform Commission (NDRC), the top economic planner.

  18. Gardening in Clay Soils

    OpenAIRE

    Wagner, Katie; Kuhns, Michael; Cardon, Grant

    2015-01-01

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

  19. Basin sidewall effects during comparable boom testing

    International Nuclear Information System (INIS)

    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.,

  20. Oil containment tests of fire booms

    International Nuclear Information System (INIS)

    Oil collection performance of five currently available fire booms were tested in an Ohmsett test tank. Test tank performance was compared with at-sea tow test results for planing/submergence failure to establish the potential for use in in-situ burning of marine oil spills. It was found that the buoyancy-to-weight ratio of the booms had a loose correlation to oil containment performance. However, it was the material and the construction of the booms that appeared to have the most significant effect on performance. Steel-skirted booms showed better performance than fabric-skirted booms, despite lower buoyancy-to-weight ratio. Performance in the tank test was better than that in at-sea tests. 7 refs., 5 tabs., 8 figs

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

    OpenAIRE

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

    2014-01-01

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

  2. Structural analysis of oil containment booms

    International Nuclear Information System (INIS)

    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

  3. Leaching of cesium and uranium from spent PWR fuel in the gel-state clays

    International Nuclear Information System (INIS)

    The amounts of cesium and uranium released from crushed spent PWR fuel in the gel-state clays with a few ml of supernatant at hot cell temperature under Ar-atmosphere have been measured. The fractions of cesium dissolved from the fuel for 873 days were 0.29 and 0.25% in Boom clay/Boom-clay water and Ca-bentonite/synthetic granitic groundwater, respectively. These cesium fractions were very close to the gap inventory of cesium, which was determined to be around 0.30% in the previous experiment. The fraction of uranium released up to 193 days in the Boom clay media was 0.011% and this fraction has been retained until 873 days. Such this phenomenon was also obtained in the Ca-bentonite media even though the released fraction was higher than that in Boom clay. The increase of less than 0.001% in the dissolved uranium fraction between 193 and 873 days suggests that the long-term leach rate of uranium from spent fuel would be much less than 24 μg·m-2·day-1. (author)

  4. Control and operation of JET articulated boom

    International Nuclear Information System (INIS)

    During the 1987 shutdown 32 toroidal limiters and 8 antennae have been installed using the JET articulated boom under visual control. Trials were done simulating remote conditions. This involved positioning of components up to 350 kg at a distance of 10 m, with 1mm accuracy. The boom has 8 main and 11 additional degrees of freedom for 3 TV camera articulated arms. The authors describe a dynamic simulation of the boom behaviour, including inertia cross coupling and elasticity of the joints, validated on the real system

  5. Anisotropy effects in a deep excavation in stiff clay

    OpenAIRE

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

    2013-01-01

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

  6. Witnessing the Booming Home Textile Market

    Institute of Scientific and Technical Information of China (English)

    Wanzy Wang

    2012-01-01

    This August, Intertextile Home Textiles concluded successfully in the city of Shanghai with record-breaking number of exhibitors and buyers, presenting the booming home textiles markets both in China and abroad.

  7. Was There Really a Popular Science "Boom"?

    Science.gov (United States)

    Lewenstein, Bruce V.

    1987-01-01

    Traces the major developments and trends in contemporary popular science. Identifies magazines, television shows, and newspaper sections devoted to popular science and discusses their status and impact. Comments on the rise, fall, and future of the "science boom." (ML)

  8. Diversion booms in the Piscataqua River, NH

    International Nuclear Information System (INIS)

    In this paper the problem of oil spills originating at the five petroleum product terminals operating on the Piscataqua River, NH is addressed through the use of diversion booms. The Piscataqua is subject to high velocity tidal currents which make normal boom deployment difficult. Diversion deployment configurations and methods of analysis were developed and tested. Procedures were applied to containment and recovery of spills occurring while tanker or barge is at a terminal for unloading

  9. Spray controller for horizontal boom movements compensation

    OpenAIRE

    El Bahir, Loussain; Lebeau, Frédéric; Destain, Marie-France; Kinnaert; Hanus, Raymond

    2002-01-01

    Longitudinal spray distribution is mainly affected by the horizontal speed variations of the nozzles. Manufacturers classically try to reduce unwanted nozzles movements using horizontal boom suspension but these methods show performance and price limitations. The purpose of this paper is to propose a spray controller aiming to compensate the effect of the horizontal boom movements on the spray distribution besides the effect of tractor speed variations. The controller is based on ...

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

    International Nuclear Information System (INIS)

    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)

  11. Sleipner mishap jolts booming Norway

    International Nuclear Information System (INIS)

    This paper reports on Norway's buoyant offshore industry that was stunned when the concrete substructure for Sleipner natural gas field's main production platform sank in the Grandsfjord off Stavanger late last month. The accident, a blow to Norway's gas sales program in Europe, came with offshore activity in the Norwegian North Sea moving into a new boom period. Currently, 10 oil and gas fields are under development, and several projects are on the drawing board. Aker Oil and Gas, a leading offshore firm, says the country's construction industry will be working at capacity for the next 4 years. Norwegian oil production has been hovering just below 2 million b/d since the beginning of this year, making Norway the North Sea's largest producer, a position formerly held by the U.K. Gas production averages about 3 bcfd. With European gas demand sharply increasing, Norway is under pressure to increase output from new fields in the mid to late 1990s. The Sleipner setback forces state owned Den norske stats oljeselskap AS (Statoil) to cast around for supplies. Sleipner was to have begun deliveries to a consortium of continental gas companies in October 1993. Statoil believes it can fill the gap from existing fields in Norwegian waters

  12. Corrosion behaviour of carbon steel in the Tournemire clay

    International Nuclear Information System (INIS)

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

  13. Disposal of radioactive waste into clay layers the most natural option

    International Nuclear Information System (INIS)

    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 (237Np, 129I,...) 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

  14. Analysis of a boom/bust cycle

    International Nuclear Information System (INIS)

    This paper sets out to measure and quantify the impact of the oil shale development cycle of the 1980's. Information used for this analysis is the recently released U.S. Census Bureau population statistics compared to the population projections made in 1980 by the Colorado West Area Council of Governments. Actually anyone who was here and experienced the oil shale development cycle in the 1980's believes it was a severe boom and bust. It is just a matter of quantifying it. Andy Gulliford, the author of open-quotes Boomtown Bluesclose quotes describes in detail how many residents experienced their own personal boom/bust cycle in our region. Anyone interested in the cause and effects of the boom/bust cycle should read a copy of his book

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

    International Nuclear Information System (INIS)

    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

  16. Effects of carbonate content on the mechanical behaviour of stiff clays

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Two deep stiff clays, the Boom and the Ypresian clays are currently investigated by the Belgian radioactive waste management agency Ondraf/Niras as potential host formations for geological disposal. Previous studies on Boom and Ypresian clays have shown significant difference in carbonate contents in Boom and Ypresian clays at different locations. Indeed; Table 1 shows that the carbonate content of the Boom clay at Essen varies with depth and is lower than that at the Mol site. Carbonate content heterogeneity was also recognized in Ypresian clay with a maximum value increasing abruptly up to 10 % in the upper part of the Roubaix member (core YP43). From a practical point of view, it is therefore essential for repository construction to understand the effect of the carbonates content on the mechanical behaviour when comparing the different materials. It is also important to determine to which extent the subsequent evolution of the repository and, possibly, the long term-performance may be affected. Odometer tests with step loading/unloading/reloading paths over low (0.05 - 3.2 MPa) and high (0.125 - 32 MPa) pressure ranges, isotropic consolidation, and consolidated drained (CD) triaxial tests with three different isotropic effective stresses (mean in-situ effective stress, 1 and 0.5 MPa) were carried out on saturated intact Boom and Ypresian clays. An example of the results obtained is shown in Figure 1a (odometer compression curves), Figure 1b (peak shear strength envelope) and Figure 1c (isotropic compression curves). Common loading/unloading/reloading loops were identified in odometer tests. Deeper examination of each path showed that the swelling slope Cs under low stress varies with the carbonate content. Nonetheless, when the sample has undergone higher stresses, the swelling slopes tend to be similar due to the progressive disruption of the fabric and inter-particles bonding as indicated in (Burland, 1990

  17. Clay Minerals and Health

    OpenAIRE

    Abdurrahman Dalgıç; Orhan Kavak

    2004-01-01

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

  18. 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...

  19. Development and explicit integration of a thermo-mechanical model for saturated clays

    International Nuclear Information System (INIS)

    This study is devoted to the thermo-mechanical constitutive modeling for saturated stiff clays and the development of a corresponding efficient stress integration algorithm. The mechanical behavior of natural Boom Clay in isothermal conditions was first characterized. The Modified Cam Clay model (MCC) was then applied to simulate the natural Boom Clay behavior. It has been found that the MCC gives poor-quality predictions of the natural Boom Clay behavior. Thereby, an adapted Cam Clay model (ACC-2) was developed by introducing a new yield surface and a new plastic potential as well as a Two-surface plastic mechanism. This model allows satisfactory prediction of the main features of the mechanical behavior of natural Boom Clay. Moreover, the constitutive equations of this model can be formulated mathematically as in a classic elasto-plastic model. Thus, the classic stress integration algorithm can be applied. The thermal effects were considered by assessing the performance of some advanced thermo-mechanical models (Cui et al., 2000; Abuel-Naga et al., 2007; Laloui and Francois, 2008; 2009). It appears that all the three models can capture the main features of the thermo-mechanical behavior of saturated clays. However, each constitutive model has its own limitations or unclear points from the theoretical point of view. The stress integration algorithm of the thermo-mechanical model proposed by Cui et al. (2000) at the stress point level was also developed using a specifically designed adaptive time-stepping scheme. The computation time required to achieve a given accuracy is largely reduced with the adaptive sub-stepping considered for both mechanical and thermal loadings. A two-surface thermo-mechanical model (TEAM model) was developed based on the two-surface plastic mechanism. The proposed model extends the model of Cui et al. (2000) to a two-surface formulation, considering the plastic strain coupling between the thermal and the mechanical loading paths. The

  20. Clays in prebiological chemistry

    Science.gov (United States)

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

    1980-01-01

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

  1. Travel time simulation of radionuclides in a 200 m deep heterogeneous clay formation locally disturbed by excavation

    OpenAIRE

    Huysmans, Marijke; Berckmans, Arne; Dassargues, Alain

    2005-01-01

    In the North of Belgium the Boom Clay Formation, at a depth of 200m below surface, is being evaluated as a potential host formation for the disposal of vitrified nuclear waste. The aim of this study is to model the transport of radionuclides through the clay, taking into account the geological heterogeneity and the excavation induced fractures around the galleries in which the waste will be stored. This is achieved by combining a transport model with geostatistical techniques used to simulate...

  2. Active suspension for a field sprayer boom

    DEFF Research Database (Denmark)

    Nielsen, Henrik Skovsgaard; Sørensen, Paul Haase

    1998-01-01

    The possibilities of implementing an active boom suspension is investigated. The performance improvement of an active suspension over a traditional passive one is studied in simulation, and shows a significant improvement. A closed-loop control system involving two ultrasonic distance transducers...

  3. Subjective loudness response to simulated sonic booms

    Science.gov (United States)

    Leatherwood, Jack D.; Sullivan, Brenda M.

    1992-01-01

    A series of laboratory studies were conducted at LaRC to: (1) quantify the effects of sonic boom signature shaping on subjective loudness; (2) evaluate candidate loudness metrics; (3) quantify the effects of signature asymmetry on loudness; and (4) document sonic boom acceptability within the laboratory. A total of 212 test subjects evaluated a wide range of signatures using the NASA Langley Research Center's sonic boom simulator. Results indicated that signature shaping via front-shock minimization was particularly effective in reducing subjective loudness without requiring reductions in peak overpressure. Metric evaluations showed that A-weighted sound exposure level, Perceived Level (Stevens Mark 7), and Zwicker's Loudness level were effective descriptors of the loudness of symmetrical shaped signatures. The asymmetrical signatures were generally rated as being quieter than symmetrical signatures of equal calculated metric level. The magnitude of the loudness reductions were observed to increase as the degree of asymmetry increased and to be greatest when the rear half of the signature was loudest. This effect was not accounted for by the loudness metrics. Sonic boom acceptability criteria were determined within the laboratory. These agreed well with results previously obtained in more realistic situations.

  4. GLOBAL Auto Shows Boom in 2007

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ China's independent brands have been booming in recent years when the country's auto industry has seen a rapid growth. They have attracted the global attention, but still need to upgrade constantly whether in technology or business performance in order to strengthen their presence in the global market and become internationalized.

  5. Flow distortion on boom mounted cup anemometers

    Energy Technology Data Exchange (ETDEWEB)

    Lindeloew-Marsden, P.; Pedersen, Troels F.; Gottschall, J.; Vesth, A.; Paulsen, R.W.U.; Courtney, M.S.

    2010-08-15

    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 with booms at the same height but pointing in 60 deg. different directions. In the examined case of a 1.9 m wide equilateral triangular lattice tower with booms protruding 4.1 m at 80 m height the measurement errors are observed to reach up to +- 2 %. Errors of this magnitude are severely problematic in the measurement of wind turbine power performance, wind resource assessment and for providing purposeful in-field comparisons between different sensors, e.g. lidar anemometers. With the proposed method, direction dependent errors can be extracted and the mast flow distortion effect on the wind measurements corrected to an uncertainty estimated to better than 0.5%. This level of uncertainty is probably acceptable for the above mentioned applications. (author)

  6. Global credit and domestic credit booms

    OpenAIRE

    Claudio Borio; Robert McCauley; Patrick McGuire

    2011-01-01

    US dollar credit is growing quickly outside the United States, especially in Asia, and in some economies it has outpaced overall credit growth. Cross-border sources of credit bear watching in view of their record of outgrowing overall credit in credit booms. Foreign currency and cross-border sources of credit raise policy issues.

  7. Local Labor Market Impacts of Energy Boom-Bust-Boom in Western Canada

    OpenAIRE

    Marchand, Joseph

    2010-01-01

    The impacts of energy price boom and bust are analyzed through the differential growth in employment and earnings between local labor markets with and without energy resources in Western Canada. The estimated differentials attributed to the boom-induced labor demand shocks show significant direct and indirect impacts on the earnings and employment within the energy extraction and other non-energy local sectors respectively. The local job multipliers indicate that job creation within the energ...

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

    International Nuclear Information System (INIS)

    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

  9. Empirically Bounding of Space Booms with Tape Spring Hinges

    OpenAIRE

    Jennings, A. L.; Black, J; C. Allen

    2013-01-01

    Self-deploying structures seek to provide a compact launch package for large, lightweight satellite booms. One self-deploying method is a foldable tape spring. This paper examines the large scale behavior of a boom attached by a tape spring hinge during mock deployments. A boom attached by tape spring to a rigid stand was released and the boom bounced up to 60° before coming to rest (as opposed to snap-through behavior). These large amplitude bounces can cause the boom to collide with sensors...

  10. 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)

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

    International Nuclear Information System (INIS)

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

  12. Experimental study of surface texture and resonance mechanism of booming sand

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The sound-producing mechanism of booming sand has long been a pending problem in the blown sand physics. Based on the earlier researches, the authors collected some silent sand samples from Tengger Desert, Australian Desert, Kuwait Desert, beaches of Hainan Island and Japanese coast as well as the soundless booming sand samples from the Mingsha Mountain in Dunhuang to make washing experiments. In the meantime the chemical corrosion experiment of glass micro-spheres, surface coating experiment and SEM examination were also conducted. The experimental results show that the sound production of booming sand seems to have nothing to do with the presence of SiO2 gel on the surface of sand grains and unrelated to the surface chemical composition of sand grains but is related to the resonance cavities formed by porous (pit-like) physical structure resulting from a number of factors such as wind erosion, water erosion, chemical corrosion and SiO2 gel deposition, etc. Its resonance mechanism is similar to that of Hemholz resonance cavity. Under the action of external forces, numerous spherical and sand grains with smooth surface and porous surface are set in motion and rub with each other to produce extremely weak vibration sound and then become audible sound by human ears through the magnification of surface cavity resonance. However the booming sands may lose their resonance mechanism and become silent sand due to the damping action caused by the invasion of finer particles such as dust and clay into surface holes of sand grains. Therefore, clearing away fine pollutants on the quartz grain surface is an effective way to make silent sand emit audible sound.

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

    Science.gov (United States)

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

    2013-12-01

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-08-31

    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

  16. The A/SUB/2Rs-B 7200. 95 boom spreader - newly developed equipment from Koethen

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, H.J.

    1984-04-01

    This paper explains design and performance of this TAKRAF boom spreader for overburden removal in brown coal surface mines. The spreader was developed for medium sized surface mines; its design is a further improvement of the A/SUB/2Rs-B 6300.95 boom spreader, employed in various surface mines in Hungary, Bulgaria and Romania. The new spreader has a spoil removal capacity of 90,000 m/SUP/3/d, a mass of 1,550 tons, spreading boom length of 95 m and a 1,800 m wide conveyor belt system. Two men operate the equipment. The first new spreader has been assembled and is ready for continuous operation in the Drmno brown coal surface mine in Yugoslavia for block working in a width of 80 m, spoil bank height of 25 m and a spreading volume of 2,000 m/SUP/3/m. Further design details and specifications are provided. (In German)

  17. Immigration and Housing Booms: Evidence from Spain

    OpenAIRE

    Gonz??lez Luna, Libertad; Ortega, Francesc

    2009-01-01

    We estimate empirically the effect of immigration on house prices and residential construction activity in Spain over the period 1998-2008. This decade is characterized by both a spectacular housing market boom and a stunning immigration wave. We exploit the variation in immigration across Spanish provinces and construct an instrument based on the historical location patterns of immigrants by country of origin. The evidence points to a sizeable causal effect of immigration on b...

  18. Stock Price Booms and Expected Capital Gains

    OpenAIRE

    Adam, Klaus; Beutel, Johannes; Marcet, Albert

    2014-01-01

    The booms and busts in U.S. stock prices over the post-war period can to a large extent be explained by fluctuations in investors' subjective capital gains expectations. Survey measures of these expectations display excessive optimism at market peaks and excessive pessimism at market troughs. Formally incorporating subjective price beliefs into an otherwise standard asset pricing model with utility maximizing investors, we show how subjective belief dynamics can temporarily delink stock price...

  19. Electronic Commerce Beyond the "dot com" Boom

    OpenAIRE

    James A. Senn

    2000-01-01

    The explosion of interest in electronic commerce stemming from commercial use of the Internet triggered high expectations, and accompanying high stock market value for public companies specializing in the delivery of products and services through this channel. However, the boom in the market value of these so-called "dot com" companies appears to be over. This paper examines the factors underlying the fall off in the value of "dot com" companies, focusing on the manner in which fundamental bu...

  20. Internet video monitoring of ice boom performance

    International Nuclear Information System (INIS)

    Ice released into the Niagara River from Lake Erie in the early freeze-up period of winter has been known to cause significant power generation losses at the hydroelectric power plants on the Niagara River. A monitoring program has been developed by the New York Power Authority and Ontario Hydro to help minimize the impacts of ice on power generation in the area. Water level gauges, water temperature probes and low-light-level television cameras are used to obtain real-time observations of certain ice and hydraulic characteristics. Visual observations of ice conditions in the vicinity of the intakes are also recorded. An ice boom, which is about 2,700 m long, is located nearly 50 km upstream from the generating stations which are about 11 km downstream of Niagara Falls. First-hand knowledge of the ice conditions at the ice boom is important for forecasting the availability of power from the Niagara River generating stations and planning possibilities for the power system. The monitoring program has proven to be useful in the evaluation of an ice boom design improvement. 25 figs

  1. Clay Mineral: Radiological Characterization

    Science.gov (United States)

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

    2008-08-01

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

  2. Clay Mineral: Radiological Characterization

    International Nuclear Information System (INIS)

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

  3. A loudness calculation procedure applied to shaped sonic booms

    Science.gov (United States)

    Shepherd, Kevin P.; Sullivan, Brenda M.

    1991-01-01

    Described here is a procedure that can be used to calculate the loudness of sonic booms. The procedure is applied to a wide range of sonic booms, both classical N-waves and a variety of other shapes of booms. The loudness of N-waves is controlled by overpressure and the associated rise time. The loudness of shaped booms is highly dependent on the characteristics of the initial shock. A comparison of the calculated loudness values indicates that shaped booms may have significantly reduced loudness relative to N-waves having the same peak overpressure. This result implies that a supersonic transport designed to yield minimized sonic booms may be substantially more acceptable than an unconstrained design.

  4. Application of Power Regenerative Boom system to excavator

    OpenAIRE

    Joo, Choonshik; Stangl, Martin

    2016-01-01

    This paper is presenting the application of Power Regenerative Boom(PRB) system to excavator. In order to increase the fuel efficiency of the excavator, potential energy of the front structure is recuperated by the hydraulic hybrid system with electric-hydraulic control, during boom down motion. Charged energy into accumulator is reused after boom down motion, the pressurized oil goes to hydraulic motor. The hydraulic motor is mounted on the engine PTO(Power Take-Off), therefore output torque...

  5. Housing Booms and Busts, Labor Market Opportunities, and College Attendance

    OpenAIRE

    Kerwin Kofi Charles; Erik Hurst; Notowidigdo, Matthew J.

    2015-01-01

    We study how the recent national housing boom and bust affected college enrollment and attainment during the 2000s. We exploit cross-city variation in local housing booms, and use a variety of data sources and empirical methods, including models that use plausibly exogenous variation in housing demand identified by sharp structural breaks in local housing prices. We show that the housing boom improved labor market opportunities for young men and women, thereby raising their opportunity cost o...

  6. Laboratory testing of a flexible boom for ice management

    International Nuclear Information System (INIS)

    Combating oil spills in the Arctic is a major challenge. Drilling or producing oil or gas in the marginal ice zone (MIZ) may allow booms to be deployed upstream of an offshore structure to clear the water of ice, thereby enabling conventional oil spill countermeasures to be used. Such a boom would be kept in place by two ice-going service vessels or by moored buoys. SINTEF NHL and NRC have performed a number of small-scale tests with a flexible boom in the NRC ice basin in Ottawa. The purpose of the tests was to measure the effectiveness of using a flexible boom for collecting ice, and to determine the loads associated with collecting the ice. In the tests, various boom configurations were towed against a broken ice field consisting of ice pieces typically 50--100 mm across and 30 mm thick. The ice concentration was usually 10/10, but it was reduced to 8/10 and 5/10 for two tests. The boom was towed at speeds of 20 and 50 mm-s-1. Both the width of the boom and the slackness of the boom were varied over reasonable ranges. Two six-component dynamometers were used to support the boom. Thus, the force components on each end of the boom were measured. Further, two video cameras were used to record the effectiveness of each boom configuration. In this paper, the full results of this test program are presented and the application of the test results to the full-scale situation are discussed. The tests show that, under certain conditions, the use of boom is feasible for ice management in oil-contaminated water

  7. Automata-Based Analysis of Stage Suspended Boom Systems

    OpenAIRE

    Anping He; Jinzhao Wu; Shihan Yang; Yongquan Zhou; Juan Wang

    2013-01-01

    A stage suspended boom system is an automatic steeve system orchestrated by the PLC (programmable logic controller). Security and fault-recovering are two important properties. In this paper, we analyze and verify the boom system formally. We adopt the hybrid automaton to model the boom system. The forward reachability is used to verify the properties with the reachable states. We also present a case study to illustrate the feasibility of the proposed verification.

  8. Deployment and Characterisation of a Telescopic Boom for Sounding Rockets

    OpenAIRE

    Wylie, Mark; Keegan, John; Curran, Stephen; Vather, Dinesh; Duffy, Paul

    2011-01-01

    In any sounding rocket, volume and mass are at a premium. Payload designers strive towards smaller, lighter and cheaper mechanisms which can achieve the same goals. This project aims to reduce the mass and volume for probe deployment booms and their deployment mechanisms. An experiment (Telescobe) to test a low cost novel method of boom deployment using telescopic carbon fibre poles was developed. A custom camera measurement system was also developed to measure boom length and harmonic deflec...

  9. Uniaxial backfill block compaction

    International Nuclear Information System (INIS)

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

  10. Performance of floating oil booms in unsheltered waters

    Science.gov (United States)

    Iglesias, Gregorio; Castro, Alberte

    2013-04-01

    Oil booms are a fundamental tool to diminish the impact of an oil spill. They tend to perform reasonably well in sheltered waters, e.g. within a harbour. However, their performance is often inadequate in open water conditions, under waves, winds and currents. And it is precisely in those conditions that they are needed if oil slicks are to be prevented from reaching certain particularly sensitive areas, such as estuaries, rias, etc. (Castro et al., 2010; Iglesias et al., 2010). In this work the performance of floating oil booms under waves and currents is assessed on the basis of laboratory experiments carried out in a state-of-the-art wave-current flume. Different oil boom models are used, representative of booms with long and short skirts and with different weights. The results show that different booms behave very differently under waves and currents, hence the importance of selecting the boom design that is appropriate for the actual conditions under which it will have to contain the oil slick. Thus, different oil booms should be used for different areas. References A. Castro, G. Iglesias, R. Carballo, J.A. Fraguela, 2010. Floating boom performance under waves and currents, Journal of Hazardous Materials 174, 226-235 G. Iglesias, A.Castro, J.A.Fraguela, 2010. Artificial intelligence applied to floating boom behavior under waves and currents, Ocean Engineering 37, 1513-1521.

  11. Clays as prebiotic photocatalysts

    Science.gov (United States)

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

    1981-01-01

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

  12. Characterization of clay minerals

    International Nuclear Information System (INIS)

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

  13. Analysis of the excavation of a deep drift in a tertiary clay

    OpenAIRE

    Vaunat, Jean; Gens Solé, Antonio; VASCONCELOS, R.; Li, X.-L.

    2011-01-01

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

  14. Multidisciplinary design optimization for sonic boom mitigation

    Science.gov (United States)

    Ozcer, Isik A.

    Automated, parallelized, time-efficient surface definition and grid generation and flow simulation methods are developed for sharp and accurate sonic boom signal computation in three dimensions in the near and mid-field of an aircraft using Euler/Full-Potential unstructured/structured computational fluid dynamics. The full-potential mid-field sonic boom prediction code is an accurate and efficient solver featuring automated grid generation, grid adaptation and shock fitting, and parallel processing. This program quickly marches the solution using a single nonlinear equation for large distances that cannot be covered with Euler solvers due to large memory and long computational time requirements. The solver takes into account variations in temperature and pressure with altitude. The far-field signal prediction is handled using the classical linear Thomas Waveform Parameter Method where the switching altitude from the nonlinear to linear prediction is determined by convergence of the ground signal pressure impulse value. This altitude is determined as r/L ≈ 10 from the source for a simple lifting wing, and r/L ≈ 40 for a real complex aircraft. Unstructured grid adaptation and shock fitting methodology developed for the near-field analysis employs an Hessian based anisotropic grid adaptation based on error equidistribution. A special field scalar is formulated to be used in the computation of the Hessian based error metric which enhances significantly the adaptation scheme for shocks. The entire cross-flow of a complex aircraft is resolved with high fidelity using only 500,000 grid nodes after only about 10 solution/adaptation cycles. Shock fitting is accomplished using Roe's Flux-Difference Splitting scheme which is an approximate Riemann type solver and by proper alignment of the cell faces with respect to shock surfaces. Simple to complex real aircraft geometries are handled with no user-interference required making the simulation methods suitable tools for

  15. 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.; Rosenberger, James L.; Philips, Daisy

    2014-01-01

    The Waveforms and Sonic boom Perception and Response (WSPR) Program was designed to test and demonstrate the applicability and effectiveness of techniques to gather data relating human subjective response to multiple low-amplitude sonic booms. It was in essence a practice session for future wider scale testing on naive communities, using a purpose built low-boom demonstrator aircraft. The low-boom community response pilot experiment was conducted in California in November 2011. The WSPR team acquired sufficient data to assess and evaluate the effectiveness of the various physical and psychological data gathering techniques and analysis methods.

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

    International Nuclear Information System (INIS)

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

  17. Trade booms, trade busts, and trade costs

    OpenAIRE

    David S. Jacks; Christopher M. Meissner; Novy, Dennis

    2009-01-01

    What has driven trade booms and trade busts in the past and present? We derive a micro-founded measure of trade frictions from leading trade theories and use it to gauge the importance of bilateral trade costs in determining international trade flows. We construct a new balanced sample of bilateral trade flows for 130 country pairs across the Americas, Asia, Europe, and Oceania for the period from 1870 to 2000 and demonstrate an overriding role for declining trade costs in the pre-World War I...

  18. Market, Government, and Israel's Muted Baby Boom

    OpenAIRE

    Yoram Ben-Porath

    1985-01-01

    Cohorts born in Israel since the late 1910s were approximately 70 percent larger than earlier cohorts. This brought about changes in the age structure that are even more dramatic than the American baby boom.This paper follows the impact of the large cohorts on the school system and on the labor market, emphasizing the role played by the public sector. In terms of the number of teaching posts the school system demonstrated on the whole a very prompt ability to adjust to the pressure of high nu...

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

    International Nuclear Information System (INIS)

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

  20. Organophilic clay suspension medium

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-10-24

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

  1. Clay Minerals: Adsorbophysical Properties

    International Nuclear Information System (INIS)

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

  2. Predicting the transverse volume distribution under an agricultural spray boom

    OpenAIRE

    Leunda, P.; Debouche, Charles; Caussin, R.

    1990-01-01

    The volume distribution of spray below individual agricultural flat-fan spray nozzles was fitted to a truncated normal distribution. This expresses the parameters as a function of the spray liquid pressure, the boom height and the nozzle orifice size. This model was used to predict the transverse distribution below an agricultural spray boom. Peer reviewed

  3. Doppler effect induced spin relaxation boom

    Science.gov (United States)

    Zhao, Xinyu; Huang, Peihao; Hu, Xuedong

    2016-03-01

    We study an electron spin qubit confined in a moving quantum dot (QD), with our attention on both spin relaxation, and the product of spin relaxation, the emitted phonons. We find that Doppler effect leads to several interesting phenomena. In particular, spin relaxation rate peaks when the QD motion is in the transonic regime, which we term a spin relaxation boom in analogy to the classical sonic boom. This peak indicates that a moving spin qubit may have even lower relaxation rate than a static qubit, pointing at the possibility of coherence-preserving transport for a spin qubit. We also find that the emitted phonons become strongly directional and narrow in their frequency range as the qubit reaches the supersonic regime, similar to Cherenkov radiation. In other words, fast moving excited spin qubits can act as a source of non-classical phonons. Compared to classical Cherenkov radiation, we show that quantum dot confinement produces a small but important correction on the Cherenkov angle. Taking together, these results have important implications to both spin-based quantum information processing and coherent phonon dynamics in semiconductor nanostructures.

  4. Design and operation of the JET articulated boom

    International Nuclear Information System (INIS)

    After tritium introduction, planned for JET about 1991, remote handling maintenance is vital to the continued operation of the machine. An articulated boom has been designed at JET as the sole support device for in-vessel transport of all equipment and servo-manipulators and is part of the JET Remote Handling plan. The boom was manufactured by NEI Thompson of Wolverhampton and AET of Coventry, England, delivered to JET in October 1984 and has been commissioned successfully to its full design performance. The boom has been used during the June 1985 maintenance period as a hands-on lifting device using a hand-held, push-button controller. Dynamic computer modelling of the boom has been carried out to analyse cross-coupling inertial effects arising in the horizontal plane. A/sup 1//5-scale, mechanical model has also been used to control the boom in a master-slave mode

  5. Re-engineering of a stainless steel fire boom for use in conjunction with conventional fire booms

    International Nuclear Information System (INIS)

    Re-engineering a large stainless steel oil retention boom to reduce its size, weight and cost is described. The large offshore stainless steel boom was redesigned to serve as a high-strength, durable burn pocket inserted between two lengths of conventional fabric fire boom. Deployment, sea-keeping, towing and retrieval characteristics of the pocket boom have been considered to be very good. Oil containment tests at Ohmsett showed that the boom can withstand catenary tow speeds of 1,5 m/sec without failure. Exposure to burning oil does not affect the oil containment characteristics of the boom; exposure to six hours of fire with full-scale heat fluxes of three hours of diesel fires and three hours of enhanced propane fires resulting in only minor damage, none of which would have detracted significantly from the boom's oil containment capabilities. The connector section incorporates various design modifications to ensure that the boom's service life will be at least one million wave cycles, or 45 days at sea at Sea State 3. 10 refs., 2 tabs., 13 figs

  6. Determination of the diffusion coefficient of ionic species in Boom Clay by electromigration. First evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Maes, N.; Moors, H.; De Canniere, P.; Aertsens, M.; Put, M.

    1997-03-01

    Classical diffusion experiments for strongly retarded radionuclides take a very long time. The migration can be accelerated considerably by applying an electrical field across a saturated porous medium (electromigration). Under the influence of the electric field, the ions will attain a constant velocity which is related to the diffusion coefficient by the law of Einstein (V=zeED/KT). The displacement of the concentration profile is a direct measure for the diffusion coefficient. A description of the problems of pH-disturbances, electro-osmosis and dispersion is given and an the feasibility of the electromigration method is evaluated.

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

    OpenAIRE

    Rosas-Camacho O.; Azizi O.; Lee S.K.; Saleh A; Macdonald D.D.; Al-Marzooqi A.; Taylor M

    2011-01-01

    The prediction of corrosion damage of canisters to experimentally inaccessible times is vitally important in assessing various concepts for the disposal of High Level Nuclear Waste. Such prediction can only be made using deterministic models, whose predictions are constrained by the time-invariant natural laws. In this paper, we describe the measurement of experimental electrochemical data that will allow the prediction of damage to the carbon steel overpack of the super container in Belgium’...

  8. 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

  9. Brazil's sugarcane boom could affect regional temperatures

    Science.gov (United States)

    Schultz, Colin

    2013-04-01

    With the world seeking to cut its dependence on fossil fuels, the use of bioethanol and other biofuels is on the rise. In Brazil, the second largest producer and consumer of bioethanol, this has led to a boom in sugarcane production. Based on new laws and trade agreements, researchers expect Brazil's production of sugarcane-derived ethanol to increase tenfold over the next decade, with considerable land being converted for growing sugarcane. Much of this expansion is expected to come at a loss of some of the country's cerrado savannas. So while a major aim of the turn to biofuels is to reduce the transfer of carbon to the atmosphere and mitigate global climate change, the shifting agricultural activity could have direct consequences on Brazil's climate by changing the region's physical and biogeochemical properties.

  10. Empirically Bounding of Space Booms with Tape Spring Hinges

    Directory of Open Access Journals (Sweden)

    A.L. Jennings

    2013-01-01

    Full Text Available Self-deploying structures seek to provide a compact launch package for large, lightweight satellite booms. One self-deploying method is a foldable tape spring. This paper examines the large scale behavior of a boom attached by a tape spring hinge during mock deployments. A boom attached by tape spring to a rigid stand was released and the boom bounced up to 60° before coming to rest (as opposed to snap-through behavior. These large amplitude bounces can cause the boom to collide with sensors, other booms or arrays causing damage or preventing full deployment. Results show the first bounce of deployment is nearly bounded by a four parameter ellipse. The ellipses of similar folds are similar also, suggesting that a model can be developed. Free-fall tests simulating the free-free condition found in microgravity also show similar elliptical motion. Envelopes that bound the extents of the boom motion allow for collisions to be prevented by adjustment of the design.

  11. Measurement of turbulent wind velocities using a rotating boom apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Sandborn, V.A.; Connell, J.R.

    1984-04-01

    The present report covers both the development of a rotating-boom facility and the evaluation of the spectral energy of the turbulence measured relative to the rotating boom. The rotating boom is composed of a helicopter blade driven through a pulley speed reducer by a variable speed motor. The boom is mounted on a semiportable tower that can be raised to provide various ratios of hub height to rotor diameter. The boom can be mounted to rotate in either the vertical or horizontal plane. Probes that measure the three components of turbulence can be mounted at any location along the radius of the boom. Special hot-film sensors measured two components of the turbulence at a point directly in front of the rotating blade. By using the probe rotated 90/sup 0/ about its axis, the third turbulent velocity component was measured. Evaluation of the spectral energy distributions for the three components of velocity indicates a large concentration of energy at the rotational frequency. At frequencies slightly below the rotational frequency, the spectral energy is greatly reduced over that measured for the nonrotating case measurements. Peaks in the energy at frequencies that are multiples of the rotation frequency were also observed. We conclude that the rotating boom apparatus is suitable and ready to be used in experiments for developing and testing sensors for rotational measurement of wind velocity from wind turbine rotors. It also can be used to accurately measure turbulent wind for testing theories of rotationally sampled wind velocity.

  12. Testing fire resistant boom in waves and flames

    International Nuclear Information System (INIS)

    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

  13. Comparative study of models for oil boom simulation

    International Nuclear Information System (INIS)

    The use of computational fluid dynamics (CFD) as a tool for simulating a variety of fluid flows, including oil spills on water was discussed. A common response to an oil spill on water is to use an oil retention boom to contain the oil, and to use a skimmer to recover it. In order to be as efficient as possible in oil recovery, the speed of oil herding should be as high as possible, but if it exceeds a critical value, boom failure can occur and the oil may escape underneath the boom because of hydrodynamic forces. In this computational study, the flows around a flat plate barrier and a real boom configuration with the same draft were compared. Results showed that the flow patterns for the two cases at low velocity were almost the same. The exception was for the boom tip and oil slick regions where small differences in velocity and pressure were noticed. It was concluded that in studying boom failure, a simple flat plate barrier can be used instead of a real boom configuration with the same draft. 9 refs., 8 figs

  14. Comparative study of models for oil boom simulation

    Energy Technology Data Exchange (ETDEWEB)

    An, C.F.; Barron, R.M. [Windsor Univ., Fluid Dynamics Research Institute, Windsor, ON (Canada)

    1998-09-01

    The use of computational fluid dynamics (CFD) as a tool for simulating a variety of fluid flows, including oil spills on water was discussed. A common response to an oil spill on water is to use an oil retention boom to contain the oil, and to use a skimmer to recover it. In order to be as efficient as possible in oil recovery, the speed of oil herding should be as high as possible, but if it exceeds a critical value, boom failure can occur and the oil may escape underneath the boom because of hydrodynamic forces. In this computational study, the flows around a flat plate barrier and a real boom configuration with the same draft were compared. Results showed that the flow patterns for the two cases at low velocity were almost the same. The exception was for the boom tip and oil slick regions where small differences in velocity and pressure were noticed. It was concluded that in studying boom failure, a simple flat plate barrier can be used instead of a real boom configuration with the same draft. 9 refs., 8 figs.

  15. 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...... procedure; and means for detecting the edges and estimating the angles of the edges of the leaves so as to discriminate between dicots and monocots; and means for activating one or more of the spray nozzles in response to detected dicots so as to selectively apply the herbicidal composition onto the sensed...

  16. Stacker/reclaimers line up for a boom time

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-11-15

    The current commodity boom and record freight rates are proving a boom for heavy materials handling plant manufacturers. New steel mills are to be built in Brazil and India. TKF has been awarded a contract for a further coal handling plant at Jimah in India. Techint, which recently acquired the German company Takraf, is to supply bucket-wheel stacker/reclaimers for the expansion of Ust-Luga coal terminal in Russia. Schade recently delivered six boom type stackers and six portal reclaimers to the Dawson coal consolidation project in Queensland. Five further stacker/reclaimers have been ordered for the Lake Linsay mine. 2 photos.

  17. Clay membrane made of natural high plasticity clay:

    DEFF Research Database (Denmark)

    Foged, Niels; Baumann, Jens

    1999-01-01

    into account advective ion transport as well as diffusion. Clay prospecting for clays rich in smectite has revealed large deposits of Tertiary clay of very high plasticity in the area around Rødbyhavn on the Danish island of Lolland. The natural clay contains 60-75% smectite, dominantly as a sodium...... have been tested successfully. At a natural water content of w=40-45% it is possible to establish a homogeneous membrane with hydraulic conductivity k...

  18. Sonic Boom Computations for a Mach 1.6 Cruise Low Boom Configuration and Comparisons with Wind Tunnel Data

    Science.gov (United States)

    Elmiligui, Alaa A.; Cliff, Susan E.; Wilcox, Floyd; Nemec, Marian; Bangert, Linda; Aftosmis, Michael J.; Parlette, Edward

    2011-01-01

    Accurate analysis of sonic boom pressure signatures using computational fluid dynamics techniques remains quite challenging. Although CFD shows accurate predictions of flow around complex configurations, generating grids that can resolve the sonic boom signature far away from the body is a challenge. The test case chosen for this study corresponds to an experimental wind-tunnel test that was conducted to measure the sonic boom pressure signature of a low boom configuration designed by Gulfstream Aerospace Corporation. Two widely used NASA codes, USM3D and AERO, are examined for their ability to accurately capture sonic boom signature. Numerical simulations are conducted for a free-stream Mach number of 1.6, angle of attack of 0.3 and Reynolds number of 3.85x10(exp 6) based on model reference length. Flow around the low boom configuration in free air and inside the Langley Unitary plan wind tunnel are computed. Results from the numerical simulations are compared with wind tunnel data. The effects of viscous and turbulence modeling along with tunnel walls on the computed sonic boom signature are presented and discussed.

  19. Rattles of Clay.

    Science.gov (United States)

    Banning, Donna

    1983-01-01

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

  20. Polyethylene/clay nanocomposites

    Czech Academy of Sciences Publication Activity Database

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

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

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

    International Nuclear Information System (INIS)

    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 (C1-C4 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

  2. Long term loading of the gallery lining in a clay host rock

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Repository construction and operation in a clay host rock - in particular in poorly indurated clays like the Boom Clay - require a structural support of the host rock excavations for several reasons. Apart from the operational safety, a well-designed structural support also minimizes the perturbation (or excavation damaged/disturbed zone) of the host formation. Furthermore, it is essential if reversibility would be a requirement in the phased development of a repository. The design of such a support depends, amongst others, on the stress state around the lining. In this paper we present the results that have been obtained through monitoring since the extension of the HADES underground research facility in 2002. The design of this extension has been based on a wedge-block lining with pre-cast concrete segments. To assess the stresses inside the lining segments, several segments were instrumented with embedded vibrating wire strain gauges during casting. The first phase of the extension was the construction of the Connecting Gallery in 2002. Strains have been monitored since then and allow assessing the stresses inside the lining, as well as deriving the stress state of the host formation around it. Based on this monitoring set-up, a similar approach was performed for the construction of the PRACLAY Gallery in 2007 where in addition to the strains, the contact pressure between the lining and host formation and the load between the segments are being monitored directly. The measurement set-ups of both the Connecting Gallery and the PRACLAY Gallery show a similar stress state, thereby increasing our confidence in the interpretation of the measurements. The strains measured in the Connecting Gallery show that the wedge-block lining presents an almost instantaneous strain increase followed by a gradual increase with time as shown in Figure 1, which represents the evolution of the measured strains with time at the

  3. Clay matrix voltammetry

    International Nuclear Information System (INIS)

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

  4. Booming shale gas production drives Texas petrochemical surge

    OpenAIRE

    Thompson, Jesse B.

    2012-01-01

    A highly profitable petrochemical industry has reemerged in Texas from the boom in U.S. shale oil-and-gas exploration, creating an internationally competitive sector that can produce a variety of products including plastics at a lower cost.

  5. Elastic Deployable Composite Tubular Roll-Out Boom Project

    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...

  6. World's Senior Population Forecast to Boom by 2050

    Science.gov (United States)

    ... gov/medlineplus/news/fullstory_157999.html World's Senior Population Forecast to Boom by 2050 Public health challenges ... 2016 (HealthDay News) -- The percentage of the world's population aged 65 and older is expected to double ...

  7. Numerical modeling of oil containment by a boom

    International Nuclear Information System (INIS)

    A hydrodynamic model of a boom for oil containment was developed. The physical phenomena which relate to oil containment were analysed. The important parameters from the analysis were used to develop a numerical model of interfacial instabilities for a two-phase system consisting of a layer of oil on top of a uniform flowing water stream. Vortex sheets were used to represent interfaces (air-water, air-oil, oil-water) and solid boundaries (boom, bottom). Flow velocities were calculated using Biot-Savart's law. The objective was to use the model to analyse oil containment failure mechanisms causing substantial loss of oil under the boom. Model calculations were found to be stable and accurate. Applications of the model to realistic cases of oil containment by a boom were presented. 33 refs., 12 figs

  8. Elastic Deployable Composite Tubular Roll-Out Boom Project

    Data.gov (United States)

    National Aeronautics and Space Administration — DSS's innovative Elastic Deployable Composite Tubular Roll-Out Boom will provide revolutionary performance when compared to conventional state-of-the-art...

  9. 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…

  10. Clay membrane made of natural high plasticity clay

    DEFF Research Database (Denmark)

    Foged, Niels; Baumann, Jens

    1998-01-01

    ion transport as well as diffusion.Clay prospection for clays rich in smectite has revealed large deposits of Tertiary clay of very high plasticity in the area around Rødbyhavn on the Danish island Lolland. The natural clay contains 60 to 75% smectite, dominantly as a sodium-type. The clay material...... successfully. At natural watercontent w = 40 to 45% it is possible to establish a homogeneous membrane with hydraulic conductivity k conductivity measured in oedometer tests used for establishing swell and deformation properties showed...

  11. 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

  12. Booms and Busts: New Keynesian and Behavioral Explanations

    OpenAIRE

    Grauwe, Paul

    2010-01-01

    Capitalism is characterized by booms and busts. Periods of strong growth in output alternate with periods of declines in economic growth. Every macro-economic theory should attempt to explain these endemic business cycle movements. In this paper I present two paradigms that attempt to explain these booms and busts. One is the DSGE-paradigm in which agents have unlimited cognitive abilities. The other paradigm is a behavioural one in which agents are assumed to have limited cognitive abilities...

  13. Dutch Disease and the Oil and Boom and Bust

    OpenAIRE

    Brock Smith

    2014-01-01

    This paper examines the impact of the oil price boom in the 1970s and the subsequent bust on non-oil economic activity in oil-dependent countries. During the boom, manufacturing exports and value added increased significantly relative to non-oil dependent countries,along with wages, employment, and capital formation. These measures decreased, though to a lesser and more gradual extent, during the bust and subsequent period of low prices, displaying a positive relationship with oil prices. How...

  14. Tracking the Boom in Queensland’s Gasfields

    Directory of Open Access Journals (Sweden)

    Will Rifkin

    2014-09-01

    The research reported in this paper, though only mid-way to completion, suggests that an action-research approach to developing indicators of cumulative impacts on housing, business, employment, liveability and trust in government shows promise for enabling stakeholders to track the multi-faceted effects of a resource boom.  We hope that such work helps stakeholders to mitigate the ups and downs of the cycle of boom, bust and recovery that can be driven by resource development.

  15. Clay membrane made of natural high plasticity clay

    DEFF Research Database (Denmark)

    Foged, Niels; Baumann, Jens

    1998-01-01

    Leachate containment in Denmark has through years been regulated by the DIF Recommendation for Sanitary Landfill Liners (DS/R 466). It states natural clay deposits may be used for membrane material provided the membrane and drainage system may contain at least 95% of all leachate created throughout...... advective ion transport as well as diffusion.Clay prospection for clays rich in smectite has revealed large deposits of Tertiary clay of very high plasticity in the area around Rødbyhavn on the Danish island Lolland. The natural clay contains 60 to 75% smectite, dominantly as a sodium-type. The clay...... coefficient being much lower than anticipated using the total porosity. These properties are of major importance to the future use of clay membranes for containment of hazardous waste. In order to explain these properties microstrutural investigations were initiated to establish boundary conditions for...

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

    International Nuclear Information System (INIS)

    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.

  17. 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.

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

    OpenAIRE

    Roberto Fioretti; Paolo Principi

    2014-01-01

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

  19. Disposal of conditioned HLW matrices and interaction with a deep clay layer as host formation

    International Nuclear Information System (INIS)

    About two decades ago the Belgian Nuclear Research Center, SCK CEN, started the construction of an underground laboratory at a depth of 250 m in the Boom Clay formation extending from 180 to 280 m depth. The shaft was dug under freezing conditions because large aquifers surmount the clay layer. The underground galleries were constructed with conventional semi-automatic tunneling machines. An extensive R and D program has been undertaken within the framework of the European Community's Research and Development Programme on the management and storage of radioactive waste. The main scientific fields of investigation are: local and regional hydrogeologic characterisation, migration of radionuclides in clay, interaction of waste forms with clay, gas migration in compact clay, corrosion of canister materials, thermal load and heat dissipation in clay, study and performance analysis of backfill materials, and safety analysis of an underground repository. The underground laboratory at Mol has been used by many partners within the European Union to carry out in situ experiments in fully representative conditions. 14 refs

  20. Thermostability of montmorillonitic clays

    Directory of Open Access Journals (Sweden)

    Petr Jelínek

    2014-05-01

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

  1. Heart Block

    Science.gov (United States)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-07-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  5. 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

  6. Population Blocks.

    Science.gov (United States)

    Smith, Martin H.

    1992-01-01

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

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

    OpenAIRE

    Marta Valaskova

    2015-01-01

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

  8. Optical MEMS: boom, bust and beyond

    Science.gov (United States)

    Ramani, Chandra Mouli

    2005-10-01

    Optical Telecommunications bandwidth, spurred by the growth of the internet, experienced unprecedented growth in the late 1990's. The creation of new enterprises was vast and the expansion of established component, system and services companies was also breathtaking. This period of speculative growth was followed in 2001-2004 by one of the most significant market crashes in history. While $20B of venture capital was invested in optical telecom in the last 10 years, the vast majority of that has been written off in the last four. Countless start-ups inaugurated with great fanfare at the end of the 20th century were unceremoniously shut down at the start of the 21st. (1) As in all speculative bubbles, innovative technologies were born and buried. Nonetheless, new capabilities emerge from the chaos and disruption; one such example is the advent of Optical MEMS (MOEMS). Its development was vigorously pursued in both academic and corporate laboratories during the boom and, in the author's view; MOEMS constitutes a powerful and versatile tool set that is an invaluable residual of the last few years. In Telecommunications, MOEMS has proven to be the technology of choice for many optical switching and wavelength management applications. (2) Variable Optical Attenuators (VOA), Wavelength Blockers (WB), Dynamic Gain Equalizers (DGE), and most recently Wavelength Selective Switches (WSS) are being used in the numerous recent network deployments. Moreover, agile networks of the future will have MOEMS at every node. This presentation will provide an overview of the history of MOEMS in Telecommunications, discuss its byproducts and project the future of the technology.

  9. Effects of clay on the dissolution behaviour of nuclear waste glass

    International Nuclear Information System (INIS)

    In the concept for the geological disposal of vitrified nuclear HLW (high-level waste), the biosphere is protected from the waste by multiple barriers, each with their specific safety functions. A first barrier is the waste matrix itself, which should be resistant against leaching, resulting in a slow radionuclide release into the surrounding host rock. As a second barrier, the previous reference disposal design for HLW glass in Belgium foresaw a bentonite buffer. The third barrier would be the Boom Clay host rock. Therefore, our laboratory has performed many experiments with glass in contact with bentonite or Boom Clay, making from the interaction of waste glass and clay an important field of expertise. The objectives of the studies on the stability of waste glass in conditions representative of the relevant disposal concept, are to create a database for the evaluation of the radiological long-term safety, and to validate certain simplified hypotheses in these evaluations, which allow the modelling of the glass dissolution behaviour

  10. Sonic boom loudness study and airplane configuration development

    Science.gov (United States)

    Brown, Jessica G.; Haglund, George T.

    1988-01-01

    Sonic boom wave form parameters as related to loudness were investigated analytically. The parameters studied include rise time, duration, maximum overpressure and initial overpressure. The design criteria of a 72 dBA for corridors and 65 dBA for unconstrained flight were chosen based on a review of human response testing. The 72 dBA criterion suggests that 1.0 psf shock waves may be acceptable. On that basis, acceptable low sonic boom wave forms were explored with respect to cruise conditions, aerodynamic lifting length requirements and configuration design at M 1.5 and M 2.4. An M 2.4 baseline arrow wing configuration was studied as a possible vehicle for M 1.5 cruise overland. Modifications made to approach the low boom wave form included a slightly longer forebody, staggered nacelles, a lifting arrow wing horizontal tail, and carefully tailored lift and volume elements. The same wave form criteria applied for M 2.4 cruise results in a low boom configuration that has significant weight, length and balance penalties. Further detailed design work is required to reach the target wave form and resultant loudness level for overland cruise at M 1.5. These results so far suggest that a properly designed M 2.4 overwater configuration may be capable of M 1.5 overland operation with sonic boom noise characteristcs that meet the criterion.

  11. First clinical experience with a novel forearm boom.

    Science.gov (United States)

    Gaulke, R; Abdulkareem, M; O'Loughlin, P F; Oszwald, M; Probst, C; Hildebrand, F; Krettek, C

    2010-01-01

    The optimal forearm boom should facilitate dynamic investigation of the wrist and approaches for wrist arthroscopy. It should be safely fixed at the operating table without any contact with the patient. It must be compatible with the arm of any patient and should be sterilisable. Repositioning of distal radius fractures, fluoroscopy and insertion of Kirschner-wires should not be restricted. According to these criteria the current investigators designed a new forearm boom which was subsequently used in 19 wrist arthroscopies and 9 distal radius fracture fixations. Twenty-eight patients with heights between 150 and 205 cm and forearm lengths between 17.5 to 37 cm were treated. Preoperatively, wrist motion was tested in those 19 wrists, that underwent wrist arthroscopy, before and after fixation by the forearm boom and any restriction due to usage of the novel device was found. The new forearm boom satisfied all of the criteria cited above. Therefore the current authors believe the new forearm boom may be valuable for the indications mentioned. PMID:21209480

  12. Research of low boom and low drag supersonic aircraft design

    Institute of Scientific and Technical Information of China (English)

    Feng Xiaoqiang; Li Zhanke; Song Bifeng

    2014-01-01

    Sonic boom reduction will be an issue of utmost importance in future supersonic trans-port, due to strong regulations on acoustic nuisance. The paper describes a new multi-objective optimization method for supersonic aircraft design. The method is developed by coupling Seebass-George-Darden (SGD) inverse design method and multi-objective genetic algorithm. Based on the method, different codes are developed. Using a computational architecture, a concep-tual supersonic aircraft design environment (CSADE) is constructed. The architecture of CSADE includes inner optimization level and out optimization level. The low boom configuration is gener-ated in inner optimization level by matching the target equivalent area distribution and actual equivalent area distribution. And low boom/low drag configuration is generated in outer optimiza-tion level by using NSGA-II multi-objective genetic algorithm to optimize the control parameters of SGD method and aircraft shape. Two objective functions, low sonic boom and low wave drag, are considered in CSADE. Physically reasonable Pareto solutions are obtained from the present optimization. Some supersonic aircraft configurations are selected from Pareto front and the optimization results indicate that the swept forward wing configuration has benefits in both sonic boom reduction and wave drag reduction. The results are validated by using computational fluid dynamics (CFD) analysis.

  13. 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.

  14. Tipping Loads of Mobile Cranes with Flexible Booms

    Science.gov (United States)

    Kiliçslan, S.; Balkan, T.; Ider, S. K.

    1999-06-01

    In this study the characteristics of a mobile crane are obtained by using a flexible multibody dynamics approach, for the determination of safe loads to prevent tipping of a mobile crane. Only the boom of the crane is assumed to be flexible since it is the only element that has considerable deflections in applications. The coupled rigid and elastic motions of the crane are formulated and software is developed in order to carry out the dynamic analysis. The variation of piston force with respect to boom angular position for different boom motion times are simulated, load curves are generated and the results are compared with experimental results obtained from a 10 t mobile crane.

  15. 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.

  16. Calculation and comparative measurement of a manipulator boom

    International Nuclear Information System (INIS)

    A manipulator system is fabricated for the use in a fusion reactor. The system allows to take in any arbitrary position in a plane. It consists of seven linked arms. During resting position, the manipulator boom is folded together in an antechamber. For the working position, the individual links are moved out through the opening to operate in a ring-shaped vacuum vessel. The stress analysis of the boom follows three steps: calculation of the global forces with a beam model dependent on the different working positions of the boom; calculation of the local stresses in the jointed arms with Finite-Element-Models for the worst load combination; and comparison of the calculations with strain gauge measurements

  17. Estimation of towing forces on oil spill containment booms

    International Nuclear Information System (INIS)

    A series of towing tests on oil retention booms are described which were carried out at the OHMSETT Test Facility to estimate the towing forces on a number of booms using a range of gap ratios, wave conditions and tow speeds. Data from the towing tests were used to develop a relationship to predict the tow force and the required tensile strength for the various boom and tow parameters. The value of the constant varied from as low as 1.2 to an average 1.9 for the calm condition, increasing sharply to an average 3.0 and 3.4 for the regular wave and harbour chop, respectively. 7 refs., 3 tabs., 1 fig

  18. Cation exchange and adsorption on clays and clay minerals

    OpenAIRE

    Ammann, Lars

    2003-01-01

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

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

    International Nuclear Information System (INIS)

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

  20. Special features of the CLUSTER antenna and radial booms design, development and verification

    Science.gov (United States)

    Gianfiglio, G.; Yorck, M.; Luhmann, H. J.

    1995-01-01

    CLUSTER is a scientific space mission to in-situ investigate the Earth's plasma environment by means of four identical spin-stabilized spacecraft. Each spacecraft is provided with a set of four rigid booms: two Antenna Booms and two Radial Booms. This paper presents a summary of the boom development and verification phases addressing the key aspects of the Radial Boom design. In particular, it concentrates on the difficulties encountered in fulfilling simultaneously the requirements of minimum torque ratio and maximum allowed shock loads at boom latching for this two degree of freedom boom. The paper also provides an overview of the analysis campaign and testing program performed to achieve sufficient confidence in the boom performance and operation.

  1. The Productivity Paradox and the Australian Mining Boom and Bust

    OpenAIRE

    Neil Dias Karunaratne

    2015-01-01

    Australia in the 1990s experienced a surge in multifactor productivity ushering in the ¡®golden age¡¯ of productivity. The subsequent 2000 decade witnessed a dramatic slump in productivity whilst the economy was riding the crest of the biggest terms- of- trade boom in its recorded history. This plummeting productivity occurring with a mining boom was a paradox. It created much concern and politicians and policymakers call for urgent action to reverse the productivity slump as it posed a threa...

  2. The Impact of the Fracking Boom on Arab Oil Producers

    OpenAIRE

    Kilian, Lutz

    2016-01-01

    This article contributes to the debate about the impact of the U.S. fracking boom on U.S. oil imports, on Arab oil exports, and on the global price of crude oil. First, I investigate the extent to which this oil boom has caused Arab oil exports to the United States to decline since late 2008. Second, I examine to what extent increased U.S. exports of refined products made from domestically produced crude oil have caused Arab oil exports to the rest of the world to decline. Third, the article ...

  3. Nuclear reactor coolant pump having a tooling boom

    International Nuclear Information System (INIS)

    A reactor coolant pump having a tooling boom mounted on the periphery of the motor stand of the pump for transferring pump components through openings in the motor stand during performance of maintenance on the pump are described. The tooling boom comprises an articulated arm mounted on the periphery of the motor stand with a gripping mechanism attached to the arm at the end opposite the arm's attachement to the motor stand. The gripping mechanism is capable of having pump components firmly attached thereto so that when the articulated arm is swung in the horizontal plane, the pump components may be transferred between the inside and outside of the motor stand

  4. Boom potential of a rotating satellite in sunlight

    Science.gov (United States)

    Lai, S. T.; Cohen, H. A.; Aggson, T. L.; Mcneil, W. J.

    1986-01-01

    An interpretation is provided for the behavior of long boom potential measurements taken on the spinning P78-2 (SCATHA) satellite at near geosynchronous altitudes. This study uses data taken during a quiet day, with the satellite in sunlight. The data show periodic variations with a maximum amplitude of 6 V. The theory explains why the variations correlate well with sun direction but not with the geomagnetic field. A current balance model, assuming a Maxwellian distribution of photoelectrons, is studied. The photoelectron temperature, the degrees of positive charging of the boom and of the satellite, and the ambient electron flux are calculated. Deviations from the model are discussed.

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

    International Nuclear Information System (INIS)

    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)

  6. Influence of vehicle configuration and flight profile on X-30 sonic booms

    Science.gov (United States)

    Maglieri, Domenic J.; Sothcott, Victor E.; Hicks, John

    1990-10-01

    The role of vehicle configuration and the flight profile on sonic booms produced by the experimental NASP X-30 is investigated. Sonic boom signatures, overpressure levels, and footprints for X-30 are presented and compared with sonic boom measurements for F-104, SR-71, Concorde, XB-70, and STS Orbiter. Results show that the sonic boom signatures for X-30 fall within those of previous high-speed planes.

  7. Modelling, simulation and optimization of agricultural sprayer boom horizontal motion behaviour

    Directory of Open Access Journals (Sweden)

    Anna-Gret Borchert

    2015-08-01

    Full Text Available The study reported here presents a method offering realistic depiction of horizontal motion behaviour of agricultural sprayer booms and for reducing the extent of the simulation model involved. Additionally, various solutions of reducing boom vibrations are presented and compared with the help of simulation. Thereby is demonstrated the extent to which boom motion behaviour on booms with large working widths can be improved through passive vibration absorbers and an active vibration isolation.

  8. The effect of clay on the dissolution of nuclear waste glass

    International Nuclear Information System (INIS)

    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

  9. Clay resources in the Netherlands

    NARCIS (Netherlands)

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

    2007-01-01

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

  10. Clay resources in the Netherlands

    NARCIS (Netherlands)

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

    2007-01-01

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

  11. Fluoride retention by kaolin clay

    DEFF Research Database (Denmark)

    Kau, P. M. H.; Smith, D. W.; Binning, Philip John

    1997-01-01

    To evaluate the potential effectiveness of kaolin clay liners in storage of fluoride contaminated waste, an experimental study of the sorption and desorption behaviour of fluoride in kaolin clay was conducted. The degree of fluoride sorption by kaolin was found to depend on solution pH and...

  12. Strength Properties of Aalborg Clay

    DEFF Research Database (Denmark)

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

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

  13. Influence of clay mineralogy on clay based ceramic products

    International Nuclear Information System (INIS)

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

  14. Evaluation of some ceramic clays from Zambia

    OpenAIRE

    Mitchell, C J

    1993-01-01

    This reports details the technical evaluation of ceramic clays collected during visits to Zambia in 1990 and 1991 by the author (Clive Mitchell). The clay samples included: Choma kaolin (Southern Province), Twapia kaolin (Copperbelt Province), Kapiri Mposhi kaolin (Central Province), Masenche clay (Northern Province), Leula clay, Misenga clay and Chikankata clay (Southern Province). The Choma kaolin was asessed to be an excellent source of ceramic-grade kaolin. The Twapia and Kapiri Mposhi ka...

  15. The Retirement Security of the Baby Boom Generation.

    Science.gov (United States)

    Shoven, John B.

    1995-01-01

    The baby boom generation faces added uncertainty on their investments and perhaps lower realized rates of return on all components of their retirement savings, primarily because of their large number. Effects will be felt in the Social Security system and by pension plans and private investors. Individuals, employers, pension fund managers, and…

  16. Dynamic modeling of oil boom failure using computational fluid dynamics

    International Nuclear Information System (INIS)

    Oil retention boom failure mechanisms have been identified and studied using computational fluid dynamics (CFD), a powerful modeling tool combining fluid dynamics and mathematics with high speed computer technology. This study utilized a commercially available CFD package, 'Fluent', to simulate the oil-water flow around a barrier. 'Drainage failure', 'droplet entrainment' and 'critical accumulation' were modeled using this software. Flow characteristics were found to be different for different failure mechanisms. In the drainage failure process, the oil slick was compressed against the barrier until the slick was deep enough for the oil to leak under the barrier. During boom failure due to droplet entrainment, the oil-water interface of the oil slick was wavy and unstable. During boom failure due to critical accumulation, the oil remained a single mass and moved under the barrier readily. The most significant observation, however, was that flow patterns around barriers are modified by the presence of oil. Therefore, towing and wave-conformity tests of booms will not be meaningful unless such tests are conducted with oil present. 15 refs., 11 figs

  17. Effect of sonic boom asymmetry on subjective loudness

    Science.gov (United States)

    Leatherwood, Jack D.; Sullivan, Brenda M.

    1992-01-01

    The NASA Langley Research Center's sonic boom apparatus was used in an experimental study to quantify subjective loudness response to a wide range of asymmetrical N-wave sonic boom signatures. Results were used to assess the relative performance of several metrics as loudness estimators for asymmetrical signatures and to quantify in detail the effects on subjective loudness of varying both the degree and direction of signature loudness asymmetry. Findings of the study indicated that Perceived Level (Steven's Mark 7) and A-weighted sound exposure level were the best metrics for quantifying asymmetrical boom loudness. Asymmetrical signatures were generally rated as being less loud than symmetrical signatures of equivalent Perceived Level. The magnitude of the loudness reductions increased as the degree of boom asymmetry increased, and depended upon the direction of asymmetry. These loudness reductions were not accounted for by any of the metrics. Corrections were determined for use in adjusting calculated Perceived Level values to account for these reductions. It was also demonstrated that the subjects generally incorporated the loudness components of the complete signatures when making their subjective judgments.

  18. 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)

  19. Clay energetics in chemical evolution

    Science.gov (United States)

    Coyne, L. M.

    1986-01-01

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

  20. Constitutive model for overconsolidated clays

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on the relationships between the Hvorslev envelope,the current yield sur-face and the reference yield surface,a new constitutive model for overconsolidated clays is proposed. It adopts the unified hardening parameter,to which the potential failure stress ratio and the characteristic state stress ratio are introduced. The model can describe many characteristics of overconsolidated clays,including stress-strain relationships,strain hardening and softening,stress dilatancy,and stress path dependency. Compared with the Cam-clay model,the model only re-quires one additional soil parameter which is the slope of the Hvorslev envelope. Comparisons with data from triaxial drained compression tests for Fujinomori clay show that the proposed model can rationally describe overconsolidated properties. In addition,the model is also used to predict the stress-strain relationship in the isotropic consolidation condition and the stress paths in the undrained triaxial compression tests.

  1. Clays in radioactive waste disposal

    OpenAIRE

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

    2010-01-01

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

  2. Boron Enrichment in Martian Clay

    OpenAIRE

    James D Stephenson; Lydia J Hallis; Kazuhide Nagashima; Freeland, Stephen J.

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest minera...

  3. 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...

  4. Barrier properties of natural clay minerals

    OpenAIRE

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

    2009-01-01

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

  5. Barrier properties of natural clay minerals

    Directory of Open Access Journals (Sweden)

    Т.В. Дудар

    2009-01-01

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

  6. Clay Minerals Deposit of Halakabad (Sabzevar- Iran)

    OpenAIRE

    Seyed Mohammad Hashemi

    2012-01-01

    Clay minerals are expanded in south of Sabzevar. They are identified with light color in the filed. The XRD and XRF chemical and mineralogical studies on the Clay minerals indicated that their main clay minerals are Kaolinite, Illite and Dickite. Pyrophyllite is minor clay mineral. Quartz and Sanidine non clay minerals are present with clay minerals .Ratio of Al2O3 is about 40 per cent, it is very good for industrial minerals .Volcanic rocks are origin clay minerals .Their composition are bas...

  7. SBR Brazilian organophilic/clay nanocomposites

    International Nuclear Information System (INIS)

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

  8. Clay minerals and sedimentary basin history

    OpenAIRE

    Merriman, Richard J.

    2005-01-01

    Clay minerals in the mud and soil that coat the Earth's surface are part of a clay cycle that breaks down and creates rock in the crust. Clays generated by surface weathering and shallow diagenetic processes are transformed into mature clay mineral assemblages in the mudrocks found in sedimentary basins. During metamorphism, the release of alkali elements and boron from clay minerals generates magmas that are subsequently weathered and recycled, representing the magma-to-mud pathway of the cl...

  9. Characterisation and engineering properties of Tiller clay

    OpenAIRE

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

    2013-01-01

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

  10. Nuclear reactor coolant pump having a tooling boom

    International Nuclear Information System (INIS)

    The tooling boom is mounted on the periphery of the motor stand of the pump for transferring pump components through openings in the motor stand during maintenance work on the pump. The tooling boom comprises a pivoted arm mounted on the periphery of the motor stand with a gripping mechanism attached to the arm at the free end. The gripping mechanism is capable of having pump components, eg. a shaft coupling firmly attached so that when the arm is swung in the horizontal plane, the pump components may be transferred between the inside and the outside of the motor stand. The arm may comprise two parts which are pivotally connected to one another. (U.K.)

  11. Active control of road booming noise in automotive interiors.

    Science.gov (United States)

    Oh, Shi-Hwan; Kim, Hyoun-suk; Park, Youngjin

    2002-01-01

    An active feedforward control system has been developed to reduce the road booming noise that has strong nonlinear characteristics. Four acceleration transducers were attached to the suspension system to detect reference vibration and two loudspeakers were used to attenuate the noise near the headrests of two front seats. A leaky constraint multiple filtered-X LMS algorithm with an IIR-based filter that has fast convergence speed and frequency selective controllability was proposed to increase the control efficiency in computing power and memory usage. During the test drive on the rough asphalt and turtle-back road at a constant speed of 60 km/h, we were able to achieve a reduction of around 6 dB of A-weighted sound pressure level in the road booming noise range with the proposed algorithm, which could not be obtained with the conventional multiple filtered-X LMS algorithm. PMID:11831793

  12. Aerodynamic Effects of a 24-foot Multisegmented Telescoping Nose Boom on an F-15B Airplane

    Science.gov (United States)

    Cumming, Stephen B.; Smith, Mark S.; Frederick, Michael A.

    2008-01-01

    An experimental multisegmented telescoping nose boom has been installed on an F-15B airplane to be tested in a flight environment. The experimental nose boom is representative of one that could be used to tailor the sonic boom signature of an airplane such as a supersonic business jet. The nose boom consists of multiple sections and could be extended during flight to a length of 24 ft. The preliminary analyses indicate that the addition of the experimental nose boom could adversely affect vehicle flight characteristics and air data systems. Before the boom was added, a series of flights was conducted to update the aerodynamic model and characterize the air data systems of the baseline airplane. The baseline results have been used in conjunction with estimates of the nose boom's influence to prepare for a series of research flights conducted with the nose boom installed. Data from these flights indicate that the presence of the experimental boom reduced the static pitch and yaw stability of the airplane. The boom also adversely affected the static-position error of the airplane but did not significantly affect angle-of-attack or angle-of-sideslip measurements. The research flight series has been successfully completed.

  13. Loudness and annoyance response to simulated outdoor and indoor sonic booms

    Science.gov (United States)

    Leatherwood, Jack D.; Sullivan, Brenda M.

    1993-01-01

    The sonic boom simulator of the Langley Research Center was used to quantify subjective loudness and annoyance response to simulated indoor and outdoor sonic boom signatures. The indoor signatures were derived from the outdoor signatures by application of house filters that approximated the noise reduction characteristics of a residential structure. Two indoor listening situations were simulated: one with the windows open and the other with the windows closed. Results were used to assess loudness and annoyance as sonic boom criterion measures and to evaluate several metrics as estimators of loudness and annoyance. The findings indicated that loudness and annoyance were equivalent criterion measures for outdoor booms but not for indoor booms. Annoyance scores for indoor booms were significantly higher than indoor loudness scores. Thus, annoyance was recommended as the criterion measure of choice for general use in assessing sonic boom subjective effects. Perceived level was determined to be the best estimator of annoyance for both indoor and outdoor booms, and of loudness for outdoor booms. It was recommended as the metric of choice for predicting sonic boom subjective effects.

  14. Ghost Block

    OpenAIRE

    Webb, Neil

    2011-01-01

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

  15. Did housing policies cause the postwar boom in homeownership?

    OpenAIRE

    Matthew Chambers; Carlos Garriga; Donald E. Schlagenhauf

    2012-01-01

    After the collapse of housing markets during the Great Depression, the U.S. government played a large role in shaping the future of housing finance and policy. Soon thereafter, housing markets witnessed the largest boom in recent history. The objective in this paper is to quantify the contribution of government interventions in housing markets in the expansion of U.S. homeownership using an equilibrium model of tenure choice. In the model, home buyers have access to a menu of mortgage choices...

  16. Managing the Oil Revenue Boom; The Role of Fiscal Institutions

    OpenAIRE

    Mauricio Villafuerte; Rolando Ossowski; Theo Thomas; Paulo A. Medas

    2008-01-01

    Oil-producing countries have benefited from rising oil prices in recent years. The increase in oil exports and oil revenues has had major implications for these countries. These developments have revealed how governments manage their fiscal policies in light of changing oil-market conditions and the role of special fiscal institutions (SFIs). In this Occasional Paper, IMF experts examine the fiscal response of oil-producing countries to the recent oil boom and the role of SFIs in fiscal manag...

  17. Thermal Behaviour of clay formations

    International Nuclear Information System (INIS)

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

  18. Epidural block

    Science.gov (United States)

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

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

    Directory of Open Access Journals (Sweden)

    E. N. Cabrera Álvarez

    2012-01-01

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

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

    OpenAIRE

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

    2011-01-01

    Soil organic carbon (OC) influences clay dispersibility, which affects soil tilth conditions and the risk of vertical migration of clay colloids. No universal lower threshold of OC has been identified for satisfactory stabilization of soil structure. We tested the concept of clay saturation with OC as a predictor of clay dispersibility and soil friability. Soil was sampled three years in a field varying in clay content (~100 to ~220 g kg-1 soil) and grown with different crop rotations. Clay ...

  1. Using CFD Surface Solutions to Shape Sonic Boom Signatures Propagated from Off-Body Pressure

    Science.gov (United States)

    Ordaz, Irian; Li, Wu

    2013-01-01

    The conceptual design of a low-boom and low-drag supersonic aircraft remains a challenge despite significant progress in recent years. Inverse design using reversed equivalent area and adjoint methods have been demonstrated to be effective in shaping the ground signature propagated from computational fluid dynamics (CFD) off-body pressure distributions. However, there is still a need to reduce the computational cost in the early stages of design to obtain a baseline that is feasible for low-boom shaping, and in the search for a robust low-boom design over the entire sonic boom footprint. The proposed design method addresses the need to reduce the computational cost for robust low-boom design by using surface pressure distributions from CFD solutions to shape sonic boom ground signatures propagated from CFD off-body pressure.

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

    International Nuclear Information System (INIS)

    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

  3. Effect of photoelectrons on boom-satellite potential differences during electron beam ejection

    International Nuclear Information System (INIS)

    Data taken on the SCATHA satellite at geosynchronous altitudes during periods of electron beam ejection in sunlight showed that the potential difference between an electrically isolated boom and the satellite main body was a function of beam current, energy, and boom-sun angle. The potential difference decreased as the boom area illuminated by the sun increased; the maximum and minimum potential differences were measured when minimum and maximum boom areas, respectively, were exposed to the sun. It is shown that photoelectrons, created on the boom, could be engulfed in the electrostatic field of the highly charged satellite main body. Theoretical calculations made using a simple current balance model showed that these electrons could provide a substantial discharging current to the main body and cause the observed variations in the potential difference between the main body and the booms. copyright American Geophysica Union 1987

  4. A study of loudness as a metric for sonic boom acceptability

    Science.gov (United States)

    Needleman, Kathy E.; Darden, Christine M.; Mack, Robert J.

    1991-01-01

    A parametric study of loudness levels with respect to weight, altitude, and Mach number for sonic boom signatures generated by two Mach 2.0 conceptual configurations is presented and compared with a similar study for nose shock overpressure. This paper discusses the relative importance of the two sonic boom metrics and the implications of the trends shown. Of the two configurations considered in this study, one was designed for optimum aerodynamic performance and the second was designed to produce a constrained overpressure sonic boom signature at cruise flight conditions. Results indicate that reductions in both loudness and overpressure level are possible when the configuration is shaped to produce a low boom signature. Results also prove that the loudness metric is a more reliable measure of the disturbance due to sonic booms than nose shock overpressure, because the overpressure does not include the sometimes significant effects of embedded shocks which are often present in mid-field low boom signatures.

  5. Analyzing price level in a booming economy: the case of Azerbaijan

    OpenAIRE

    Hasanov, Fakhri

    2011-01-01

    The study analyzes price level in Azerbaijani economy over the period of 2000-2007 by employing a specific approach. The paper concludes that price increases caused by a resource boom differs from the price increases generated by a non-booming economy. Thereby, inflation mainly caused by resource boom has its own specific features in terms of impact on economy and therefore requires specific policy response. Some policy recommendations related to monetary and fiscal policies are suggested for...

  6. A Numerical Method of Large-Scale Concrete Displacing Boom Dynamic and Experimental Validation

    OpenAIRE

    Wu Ren; Yun-xin Wu; Zhao-wei Zhang; Wen-ze Shi

    2014-01-01

    Concrete displacing boom is large-scale motion manipulator. During the long distance pouring the postures needs to frequently change. This makes the real-time dynamic analysis and health monitoring difficult. Virtual spring-damper method is adopted to establish the equivalent hydraulic actuator model. Besides boom cylinder joint clearance is taken into account. Then transfer matrix method is used to build the multibody concrete placing boom model by dividing the system into two substructures....

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

    International Nuclear Information System (INIS)

    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.)

  8. From boom to bust in the credit cycle: the role of mortgage credit

    OpenAIRE

    Bezemer, Dirk; Zhang, L.

    2014-01-01

    Based on newly collected data on 37 economies over 1970-2012, we provide a rich description of 187 credit booms, credit busts and other episodes. We explore the changing composition of bank credit over the credit cycle. In an event analysis we chart changes in capital flows, regulation, productivity and house prices over credit booms and busts. We also ask which credit boom eatures are connected to a subsequent credit growth contraction. We find that the interaction of mortgage credit growth ...

  9. Gas migration through bentonite clay

    International Nuclear Information System (INIS)

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

  10. Boron enrichment in martian clay.

    Directory of Open Access Journals (Sweden)

    James D Stephenson

    Full Text Available We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration.

  11. Boron enrichment in martian clay.

    Science.gov (United States)

    Stephenson, James D; Hallis, Lydia J; Nagashima, Kazuhide; Freeland, Stephen J

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration. PMID:23762242

  12. A dynamic model of mobile concrete pump boom based on discrete time transfer matrix method

    Science.gov (United States)

    Ren, Wu; Wu, Yunxin; Zhang, Zhaowei

    2013-12-01

    Mobile concrete pump boom is typical multibody large-scale motion manipulator. Due to posture constantly change in working process, kinematic rule and dynamic characteristic are difficult to solve. A dynamics model of a mobile concrete pump boom is established based on discrete time transfer matrix method (DTTMM). The boom system is divided into sub-structure A and substructure B. Sub-structure A is composed by the 1st boom and hydraulic actuator as well as the support. And substructure B is consists of the other three booms and corresponding hydraulic actuators. In the model, the booms and links are regarded as rigid elements and the hydraulic cylinders are equivalent to spring-damper. The booms are driven by the controllable hydraulic actuators. The overall dynamic equation and transfer matrix of the model can be assembled by sub-structures A and B. To get a precise result, step size and integration parameters are studied then. Next the tip displacement is calculated and compared with the result of ADAMS software. The displacement and rotation angle curves of the proposed method fit well with the ADAMS model. Besides it is convenient in modeling and saves time. So it is suitable for mobile concrete pump boom real-time monitoring and dynamic analysis. All of these provide reference to boom optimize and engineering application of such mechanisms.

  13. Numerical study on (porous) net-boom systems - Front net inclined angle effect

    International Nuclear Information System (INIS)

    A commercial computational fluid dynamics (CFD) software, - FLUENT - was used to simulate the flow of oil and water against a a family of net-boom structures in which the angle of inclination of the front is varied. The study also aimed at gaining a better understanding of the physical mechanisms which cause oil to escape under the rear boom. From the simulation and analysis it was concluded that critical velocity was significantly affected by the flow rate inside the net-boom region, that the highest critical velocity was achieved when the the front is nearly vertical or slightly inclined forward, and that there is an excellent potential to raise the critical velocity by deliberately designing net-boom structures. For a single solid boom, the critical velocity was found to be 0.3 to 0.4 metre/sec. A solid boom with front perforated plates may increase critical velocity to 0.5 metre/sec. A solid boom with a partially perforated front plate, which has a solid upper part, will raise the critical velocity to one metre/sec. Results of this investigation suggest that a properly-designed net-boom structure could raise the critical velocity to about two metres/sec, or even higher. Experimental data and the computed numerical velocity profiles are in reasonably good agreement, confirming the hypothesis that computational fluid dynamics can be used as reliable predictive tools for oil boom analysis and design. 16 refs., 13 figs

  14. Ohmsett's propane-fuelled test system for fire-resistant boom

    International Nuclear Information System (INIS)

    A propane-fuelled system for testing fire-resistant booms was installed at Ohmsett in the fall of 1998, the objective being to expose candidate booms to air-enhanced propane flames and waves, to reproduce a realistic in situ burning environment equal to that of a diesel or crude oil fire. Four fire boom systems have been successfully tested to date. The larger objective is to develop a complete boom performance evaluation system included this and other parameters such as towing performance and the ability to contain hot oil after exposure to flames. 5 refs., 8 figs

  15. Role of clay microstructure in expandable buffer clay

    Czech Academy of Sciences Publication Activity Database

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

    2012-01-01

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

  16. Biodegradable Pectin/clay Aerogels

    Science.gov (United States)

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

  17. Geotechnical properties of Karwar marine clay

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  18. Lateral Cutoff Analysis and Results from NASA's Farfield Investigation of No-Boom Thresholds

    Science.gov (United States)

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

    2016-01-01

    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 (AFRC) and the NASA Langley Research Center (LaRC), in partnership with other industry organizations and academia, 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 test helped to build a dataset that will go toward further understanding of the unique acoustic propagation characteristics near the sonic boom carpet extremity. The FaINT was an effort that collected finely-space sonic boom data across the entire lateral cutoff transition region. A major objective of the effort was to investigate the acoustic phenomena that occur at the audible edge of a sonic boom carpet, including the transition and shadow zones. A NASA F-18B aircraft made supersonic passes such that its sonic boom carpet transition zone would intersect a linear 60-microphone, 7500-ft long array. A TG-14 motor glider equipped with a microphone on its wing also attempted to capture the same sonic boom rays that were measured on the ground, at altitudes of 3000 - 6000 ft above ground level. This paper determined an appropriate metric for sonic boom waveforms in the transition and shadow zones called Perceived Sound Exposure Level, and established a value of 65 dB as a limit for the acoustic levels defining the lateral extent of a sonic boom's noise region; analyzed the change in sonic boom levels as a function of distance from flight path both on the ground and 4500 ft above the ground; and compared between sonic boom measurements and numerical predictions.

  19. Mass-Boom Versus Big-Bang: An Alternative Model

    Science.gov (United States)

    Alfonso-Faus, Antonio

    2006-03-01

    In an effort to advance a first step in the long journey to harmonize Einstein's General Relativity with Quantum Mechanics, we interpret the gravitational field as a sea of gravity quanta. We calculate the value of the mass of these quanta by imposing the condition that their energy cannot be localized in the Universe (a General Relativity property of the gravitational field energy). These quanta have negative energy that is emitted in each quantum, one by one, from every fundamental particle with gravitational properties. It follows that the emitting positive masses increase their value linearly with cosmological time (this effect is what we call the Mass-Boom and is present in the entire Universe). In particular, it turns out that the mass of the Universe M is equivalent to its age t, and to its gravitational entropy S, (i.e. M = t = S), in a certain system of units that convert many fundamental laws to very simple relations. This is the Mass- Boom cosmological model, which we have published elsewhere under various points of view (all giving the same result). The Mass-Boom cosmological model is identical to the one that Einstein initially proposed: a static, finite, curved and unlimited model, that today we know is stable. The Hubble observation of the red shifts, as a possible indication of an expanding Universe, is here interpreted in a very different way: we consider our LAB systems not to be rigid, fixed in size. If the Universe is the static (rigid) general reference, as Einstein first saw, then the Hubble observations must be interpreted as a proof of a local shrinkage of the quantum world. Instead of an expanding Universe we get the picture of a contracting quantum world. This new view is very well justified because it explains many of the problems that have plagued the standard model (the big-bang). It also eliminates the need for additions/corrections to the standard model, like the addition of ``inflation'', to solve the inconsistencies of the model

  20. Asia-Pacific focus of coming LNG trade boom

    International Nuclear Information System (INIS)

    This paper reports that the Asia-Pacific region remains the centerpiece of a booming world trade in liquefied natural gas. Biggest growth in LNG demand is expected from some of the region's strongest economies such as Japan, South Korea, and Taiwan, Key LNG exporters such as Brunei, Malaysia, and Indonesia are scrambling to implement projects to meet that expected demand growth. Uncertainties cloud the outlook for Far East LNG trade, Australia, for one, is more cautious in pressing expansion of its LNG export capacity as more competing LNG expansions spring up around the world, notably in the Middle East and Africa

  1. CFD Simulations Of Sonic Booms In Near And Mid Fields

    Science.gov (United States)

    Cheung, Samson H.; Edwards, Thomas A.; Lawrence, Scott L.

    1992-01-01

    Report discusses computational fluid dynamics (CFD) to simulate generation and propagation of sonic booms in near- and mid-field regions of supersonic flows about simplified bodies representative of advanced airplanes. Parabolized Navier-Stokes equations integrated by implicit, approximate-factorization, finite-volume algorithm in which crossflow inviscid fluxes evaluated by Roe's flux-difference-splitting scheme. Near-field solutions obtained by applying algorithm to flows immediately surrounding bodies. Solutions transferred to computer codes based on Whitham"s F-function theory for extrapolation to far-field.

  2. 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...... was not correlated with growth in the same year. However, year‐class strength was significantly correlated with adult growth the previous year, together with temperature during the months following spawning. The age structure shows that this species is very long lived (>30 years), but that a considerable proportion...... abundance...

  3. 21 CFR 186.1256 - Clay (kaolin).

    Science.gov (United States)

    2010-04-01

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

  4. Sorption of Cesium on Latvia clays

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  6. GEOSYNTHETIC CLAY LINERS (GCLS) IN LANDFILL COVERS

    Science.gov (United States)

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

  7. Geostatistical analysis of field hydraulic conductivity in compacted clay

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-05-01

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

  8. Blocked strainers

    International Nuclear Information System (INIS)

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

  9. In-situ testing of nuclear waste glasses in a clay laboratory - Results after two years corrosion

    International Nuclear Information System (INIS)

    The first retrieval of an in-situ experiment on the interaction waste form - clay host in the underground laboratory under the Mol site has been finished successfully. The test consisted in a two years exposure of various candidate simulated waste glasses at 90C to Boom clay. The retrieval was done by overcoring. The experimental data showed satisfactorily correspondence between in-situ and laboratory simulation tests both for mass loss and surface analytical data, supporting the validity of the in-situ test as it was performed. The thickness of waste form dissolved within two years varies between 40 and 325 μm (case of the high-level waste glasses), depending on the composition. Matrix dissolution is expected to be the major mechanism of interaction

  10. STRUCTURING & RHEOLOGY OF MOLTEN POLYMER/CLAY NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Yuan-ze Xu; Yi-bin Xu

    2005-01-01

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

  11. 30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... follows: Nominal power line voltage (in 1,000 volts) Minimum distance (feet) 69 to 114 12 115 to 229 15... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Booms and masts; minimum distance from high...; minimum distance from high-voltage lines. The booms and masts of equipment operated on the surface of...

  12. 76 FR 20530 - Safety Zone; Boom Days, Buffalo Outer Harbor, Buffalo, NY

    Science.gov (United States)

    2011-04-13

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Boom Days, Buffalo Outer Harbor, Buffalo... temporary safety zone in the Buffalo Outer Harbor, Buffalo, NY for the Boom Days Fireworks. This zone is intended to restrict vessels from Doug's Dive, the NFTA small boat harbor and a portion of the...

  13. Continued development of a test for fire booms in waves and flames

    International Nuclear Information System (INIS)

    The durability of a fire resistant boom and its ability to contain oil during an in situ burn without creating any environmental damage as a result of the burning crude was evaluated. The screening test included four stages: (1) the pre-burn wave stress stage, where the test boom was flexed under tension in waves to simulate deployment of the boom and transit to the spill site, (2) the burn in wave stage, where the test boom was exposed to waves and repeated on hourly cycles of a propane gas fire to simulate oil burning operations, (3) the post-burn wave stress stage, where the test boom was again flexed under tension in waves to simulate retrieval of the boom, and (4) the oil-containment stage, where the ability of the boom to contain thick pools of hot oil was assessed. Three recommendations were made after the test program: (1) increase the heat generated by fire, (2) increase the tension on the boom, and (4) improve the data acquisition system. 10 refs., 10 tabs., 13 figs

  14. On America’s Baby Boom Generation and It’s Social Problems

    Institute of Scientific and Technical Information of China (English)

    杨娜

    2014-01-01

    Baby boom generation is the larger than expected generation in U.S born shortly after World War II. This post- World War II phenomenon upsets the phenomenon which had been a century-long decline in the U.S fertility rate. This paper simply analyzed America’s baby boom generation from three aspects.

  15. The ARCHIMEDE-ARGILE project: acquisition and regulation of the water chemistry in a clay formation

    International Nuclear Information System (INIS)

    The first aim of the CEC/ANDRA project known as ARCHIMEDE-ARGILE is to gain an understanding on the mechanisms of acquisition and regulation of the water chemistry in a clay environment. This step is essential for predicting both the behaviour and the migration in solution of artificial elements which are initially absent in clay formation. The second aim is to assess sampling methodology and data collection techniques for key physico-chemical parameters (pH, Eh, pCO2, CEC, alkalinity...) which are the basis of the geochemical modelling of the behaviour of natural and artificial radioelements. Six drill holes have been performed in 1992 in the sliding ribs gallery in the Underground Research Facility (URF) at Mol. The study has demonstrated the importance of in situ measurements for key parameters that cannot be rigorously evaluated otherwise: redox, pH, pCO2. Fluid geochemistry can realistically be modelled using equilibrium models, in which cation exchange must be taken into account. Bacterial studies have revealed the importance of human activity on the microbial equilibrium of the formation. This paper presents the main results obtained during the first two years of the project with emphasis on determination of the hydrochemical characteristics of the Boom clay. (author). 12 refs., 4 figs., 1 tab

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-11-25

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

  17. Sound, infrasound, and sonic boom absorption by atmospheric clouds.

    Science.gov (United States)

    Baudoin, Michaël; Coulouvrat, François; Thomas, Jean-Louis

    2011-09-01

    This study quantifies the influence of atmospheric clouds on propagation of sound and infrasound, based on an existing model [Gubaidulin and Nigmatulin, Int. J. Multiphase Flow 26, 207-228 (2000)]. Clouds are considered as a dilute and polydisperse suspension of liquid water droplets within a mixture of dry air and water vapor, both considered as perfect gases. The model is limited to low and medium altitude clouds, with a small ice content. Four physical mechanisms are taken into account: viscoinertial effects, heat transfer, water phase changes (evaporation and condensation), and vapor diffusion. Physical properties of atmospheric clouds (altitude, thickness, water content and droplet size distribution) are collected, along with values of the thermodynamical coefficients. Different types of clouds have been selected. Quantitative evaluation shows that, for low audible and infrasound frequencies, absorption within clouds is several orders of magnitude larger than classical absorption. The importance of phase changes and vapor diffusion is outlined. Finally, numerical simulations for nonlinear propagation of sonic booms indicate that, for thick clouds, attenuation can lead to a very large decay of the boom at the ground level. PMID:21895057

  18. Technetium migration in natural clays

    International Nuclear Information System (INIS)

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

  19. 自动调平喷杆式喷药机设计与试验研究%Design and Experimental Research on Automatic Levelling Boom Sprayer

    Institute of Scientific and Technical Information of China (English)

    王佳文; 杨自栋

    2016-01-01

    For the characters of undulating gentle slope of arable land and the different height of different crops, we de-sign this boom sprayer.The spray bar could remain parallel to the ground.The boom sprayer could lift freely within the al-lowable range through the hydraulic system.The boom sprayer also could complete the leveling work in the field.The spray bar is lifted by the hydraulic system and movable block.The spring and balancing dampers are used to complete the mechanical leveling work of spray bar.The boom sprayer plays a positive role in Improving the utilization of pesticides and reducing crop production costs.%针对耕地存在缓坡起伏及不同农作物具有不同的植株高度的特点,设计一套能够自由调节喷杆高度的喷杆式喷药机. 该机喷杆始终保持与地面平行,使喷药机在田间工作时能够通过液压系统进行自由提升,且在田间工作时可利用机械部件完成喷杆的调平工作. 系统利用动滑轮和液压系统完成喷杆的提升,利用弹簧和阻尼器完成喷杆的机械调平工作. 该喷药机对提高农药的利用率、降低农作物生产成本都具有积极的推动作用.

  20. Mineral acquisition from clay by budongo forest chimpanzees

    NARCIS (Netherlands)

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

    2015-01-01

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

  1. Clay-based Nanocomposites Possibilities and Limitations

    Science.gov (United States)

    Papoulis, Dimitris

    2011-09-01

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

  2. Preparation and characterization of bentonite organo clay

    International Nuclear Information System (INIS)

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

  3. Sorption of cesium on Latvian clays

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Roberto Fioretti

    2014-10-01

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

  5. Contact micromechanics in granular media with clay

    Energy Technology Data Exchange (ETDEWEB)

    Ita, S.L.

    1994-08-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  7. Modernity and putty-clay

    Science.gov (United States)

    Ganesh, Trichur Kailas

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

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

    Science.gov (United States)

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

    2011-08-01

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

  9. Active control of shocks and sonic boom ground signal

    Science.gov (United States)

    Yagiz, Bedri

    The manipulation of a flow field to obtain a desired change is a much heightened subject. Active flow control has been the subject of the major research areas in fluid mechanics for the past two decades. It offers new solutions for mitigation of shock strength, sonic boom alleviation, drag minimization, reducing blade-vortex interaction noise in helicopters, stall control and the performance maximization of existing designs to meet the increasing requirements of the aircraft industries. Despite the wide variety of the potential applications of active flow control, the majority of studies have been performed at subsonic speeds. The active flow control cases were investigated in transonic speed in this study. Although the active flow control provides significant improvements, the sensibility of aerodynamic performance to design parameters makes it a nontrivial and expensive problem, so the designer has to optimize a number of different parameters. For the purpose of gaining understanding of the active flow control concepts, an automated optimization cycle process was generated. Also, the optimization cycle reduces cost and turnaround time. The mass flow coefficient, location, width and angle were chosen as design parameters to maximize the aerodynamic performance of an aircraft. As the main contribution of this study, a detailed parametric study and optimization process were presented. The second step is to appraise the practicability of weakening the shock wave and thereby reducing the wave drag in transonic flight regime using flow control devices such as two dimensional contour bump, individual jet actuator, and also the hybrid control which includes both control devices together, thereby gaining the desired improvements in aerodynamic performance of the air-vehicle. After this study, to improve the aerodynamic performance, the flow control and shape parameters are optimized separately, combined, and in a serial combination. The remarkable part of all these

  10. Nano dust impacts on spacecraft and boom antenna charging

    CERN Document Server

    Pantellini, Filippo; Meyer-Vernet, Nicole; Zaslavsky, Arnaud

    2012-01-01

    High rate sampling detectors measuring the potential difference between the main body and boom antennas of interplanetary spacecraft have been shown to be efficient means to measure the voltage pulses induced by nano dust impacts on the spacecraft body itself (see Meyer-Vernet et al, Solar Phys. 256, 463 (2009)). However, rough estimates of the free charge liberated in post impact expanding plasma cloud indicate that the cloud's own internal electrostatic field is too weak to account for measured pulses as the ones from the TDS instrument on the STEREO spacecraft frequently exceeding 0.1 V/m$. In this paper we argue that the detected pulses are not a direct measure of the potential structure of the plasma cloud, but are rather the consequence of a transitional interruption of the photoelectron return current towards the portion of the antenna located within the expanding cloud.

  11. Instrumentation for measurement of aircraft noise and sonic boom

    Science.gov (United States)

    Zuckerwar, A. J. (Inventor)

    1975-01-01

    A jet aircraft noise and sonic boom measuring device which converts sound pressure into electric current is described. An electric current proportional to the sound pressure level at a condenser microphone is produced and transmitted over a cable, amplified by a zero drive amplifier and recorded on magnetic tape. The converter is comprised of a local oscillator, a dual-gate field-effect transistor (FET) mixer and a voltage regulator/impedance translator. A carrier voltage that is applied to one of the gates of the FET mixer is generated by the local oscillator. The microphone signal is mixed with the carrier to produce an electrical current at the frequency of vibration of the microphone diaphragm by the FET mixer. The voltage of the local oscillator and mixer stages is regulated, the carrier at the output is eliminated, and a low output impedance at the cable terminals is provided by the voltage regulator/impedance translator.

  12. China expands refining sector to handle booming oil demand

    International Nuclear Information System (INIS)

    China's refining sector is in the midst of a major expansion and reorganization in response to booming domestic demand for petroleum products. Plans call for hiking crude processing capacity to 3.9 million b/d in 1995 from the current 3.085 million b/d. Much of that 26% increase will come where the products demand growth is the strongest: China's coastal provinces, notably those in the southeast. Despite the demand surge, China's refineries operated at only 74% of capacity in 1991, and projections for 1992 weren't much better. Domestic crude supply is limited because of Beijing's insistence on maintaining crude export levels, a major source of hard currency foreign exchange. The paper discusses the superheated demand; exports and imports; the refining infrastructure; the Shenzhen refinery; Hong Kong demand; southeast coast demand; 1993 plans; and foreign investment

  13. The design, construction, and observation of permanently installed safety booms in ice covered waters

    Energy Technology Data Exchange (ETDEWEB)

    Abdelnour, R.; Abdelnour, E.; Comfort, G. [BMT Fleet Technology Ltd., Kanata (Canada)

    2008-07-01

    In order to minimize potential accidents resulting from accidental intrusion, safety booms have been deployed near hydroelectric power plants to warn boaters of fast water currents. In cold regions, the booms are installed in early June and removed in October to avoid ice damage. However, in some years substantial delays caused by high river flow have meant that the booms were installed only after the summer boating season was underway. In addition, because the window of opportunity between the desired date of removal of these booms and the start of ice formation is sometimes quite short, it can be difficult to decide on a removal date. This paper described the design, construction, and observation of a typical safety boom that was installed in the summer of 2006 at the headpond of the Bark Lake flow control dam operated by Ontario Power Generation. The boom design considerations included prevailing ice conditions at the site; historical water discharge and associated currents; water level fluctuations; and the ice observed during the winter of 2007. Design challenges and improvements were also discussed. The boom has performed as expected and has remained in the water year-round for the past 2 years. It was concluded that the project has achieved success in providing river users with a warning system that remains in place until the beginning of the ice freeze up and is ready again in the spring as soon as the ice disappears. 5 refs., 4 tabs., 15 figs.

  14. Tracking the Boom in Queensland’s Gasfields

    Directory of Open Access Journals (Sweden)

    Will Rifkin

    2014-09-01

    Full Text Available During rapid resource development in a highly contested arena, effective processes for characterising cumulative, social and economic impacts are needed. In this article, we explain a strategy that uses an iterative process involving stakeholders to identify indicators of impacts of onshore natural gas development. The aim of the strategy is to arrive at a small set of indicators that those in the community, government and industry agree are salient and credible.Four major joint ventures are investing more than A$60 billion to tap Queensland, Australia’s onshore natural gas resources. Thousands of wells are reaching into natural gas in seams of coal that lie below aquifers that residents refer to as essential for their heavily agricultural region. The magnitude of these developments has been depicted as threatening the traditional base of political power that has rested with farmers. Nearby coal mining has given some communities the experience of the boomtown cycle, but it is placing unfamiliar strains on municipal resources in other towns. Gas companies provide funds in attempts to mitigate impacts, satisfying requirements of their elaborate social impact management plans (SIMPs.The research reported in this paper, though only mid-way to completion, suggests that an action-research approach to developing indicators of cumulative impacts on housing, business, employment, liveability and trust in government shows promise for enabling stakeholders to track the multi-faceted effects of a resource boom.  We hope that such work helps stakeholders to mitigate the ups and downs of the cycle of boom, bust and recovery that can be driven by resource development.

  15. Ice-load measurements on the Lake Erie-Niagara River ice boom: 1996-97

    International Nuclear Information System (INIS)

    The design and installation of a new ice boom at the entrance to the upper Niagara River at the north-east end of Lake Erie was described. Each year since 1964, the New York Power Authority and Ontario Hydro install a 2,700-meter long ice boom which spans the outlet of Lake Erie about three kilometres upstream of the Peace Bridge. The ice boom minimizes the impacts of ice on power generation in the Niagara River in the early freeze-up period of winter. A monitoring program has been developed in which water level gauges, water temperature probes and low-light-level television cameras are used to obtain real-time observations of certain ice and hydraulic characteristics. Visual observations of ice conditions in the vicinity of the New York Power Authority's intakes were also recorded. As a result of the monitoring program, a new boom design was developed which called for replacing the boom's Douglas Fir timbers with 0.76 m-diameter, 9.1 m-long steel pipe pontoons. In the 1996-97 season, the timbers in the boom were replaced with the steel pipe pontoons to evaluate the effectiveness of the new design through an ice load measurement program. The cable tensions and boom submergence at the three anchoring locations along the boom were measured. Several recommendations were made. In general, it was concluded that if the ice booms were composed entirely of steel pontoons, the release of ice into the river would be substantially reduced. 7 refs., 14 figs

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

    International Nuclear Information System (INIS)

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

  17. From clay bricks to deep underground storage

    International Nuclear Information System (INIS)

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

  18. Measuring and Modeling the Plasticity of Clays

    Directory of Open Access Journals (Sweden)

    Fernando Augusto de Andrade

    2010-09-01

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

  19. Thermal stability of PMMA–clay hybrids

    Indian Academy of Sciences (India)

    Tanushree Choudhury; Nirendra M Misra

    2010-04-01

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

  20. Structural studies of pillared clays and modified pillared clays

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-11-01

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

  1. Methodology for the Regulation of Boom Sprayers Operating in Circular Trajectories

    OpenAIRE

    Alfredo Serreta; Francisco Javier Garcia-Ramos; Mariano Vidal; Antonio Boné

    2011-01-01

    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 t...

  2. 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

  3. Methodology for the regulation of boom sprayers operating in circular trajectories.

    Science.gov (United States)

    Garcia-Ramos, Francisco Javier; Vidal, Mariano; Boné, Antonio; Serreta, Alfredo

    2011-01-01

    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/m(2)). 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 the sprayer

  4. Remediation of floating, open water oil spills: Comparative efficacy of commercially available polypropylene sorbent booms

    International Nuclear Information System (INIS)

    Several complex methods of remediation are applied to open water oil spills. Sorbing the liquid hydrocarbons with polypropylene booms is an effective and less complex means of treating such events. There are, however, a variety of commercially available booms which display different performances in sorbing different viscosity hydrocarbons. There is no acceptable A.S.T.M. protocol to evaluate these booms for performance efficiency in various weather and hydrocarbon viscosity scenarios. The current paper proposes such a protocol and evaluates the most commonly used sorbent products with the new test procedures. Nine specific performance criteria, based on actual field applications, are demonstrated

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

    Science.gov (United States)

    Starkey, Harry C.; Blackmon, Paul D.

    1979-01-01

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

  6. The plastic limit of clays

    OpenAIRE

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

    2013-01-01

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

  7. Radiological assessment of pharmaceutical clays

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

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

  9. Retention processes in clay-rocks

    OpenAIRE

    Tournassat, Christophe; Grangeon, Sylvain

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Kebede Woldetsadik

    2011-06-01

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

  11. Use of clays as buffers in radioactive repositories

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Radosavljević Slobodan

    2014-01-01

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

  13. The many ways of making anionic clays

    Indian Academy of Sciences (India)

    Michael Rajamathi; Grace S Thomas; P Vishnu Kamath

    2001-10-01

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

  14. Iodide uptake by negatively charged clay interlayers?

    Science.gov (United States)

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

    2015-09-01

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

  15. Organic waste treatment with organically modified clays

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Duška Rokavec

    2002-01-01

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

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

    OpenAIRE

    Karpiński B.; Szkodo M.

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-04-01

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

  19. On the dynamic response and collapse of slender guyed booms for space application

    Science.gov (United States)

    Housner, J. M.; Belvin, W. K.

    1983-01-01

    A procedure is developed for the analysis of the nonlinear transient response of an initially imperfect slender guyed boom having a concentrated mass at the tip. The analysis is compared with laboratory experiments, and the validated procedure is employed to study the transient response of a boom to suddenly applied step loads and prescribed initial velocities. Both cases approximate the transient conditions associated with commencing and terminating a slewing maneuver in space. Two nonlinear effects are examined, namely cable slackening and beam column behavior. It is shown that dynamic buckling of the boom may occur with excitations which result in slackening of a cable. It is also shown that transverse boom tip deflections are sensitive only to initial eccentricities when certain threshold values are exceeded. Design guidelines are established for combinations of pulse level and duration which meet performance requirements for allowable deflections.

  20. Control of large spaceborne antenna systems with flexible booms by mechanical decoupling

    Science.gov (United States)

    Wang, P. K. C.

    1983-01-01

    A simple practical method for designing antenna-feed attitude control systems for large deployable spaceborne antenna systems with long flexible booms is proposed. The basic idea is to mechanically decouple the antenna-feed from the boom so that the feed-attitude control system can be designed without taking the boom dynamics into consideration, thus avoiding a complex control problem involving an infinite-dimensional distributed parameter system. The validity of the proposed method is substantiated by analytical and numerical studies using a mathematical model for the flexible boom which could undergo both bending and torsional vibrations. This approach leads to simple antenna-feed attitude control systems which are amenable to physical implementation.

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

    International Nuclear Information System (INIS)

    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

  2. Second phase evaluation of a protocol for testing fire-resistant oil containment boom

    International Nuclear Information System (INIS)

    The second series of fire tests for fire-resistant containment booms were conducted in a wave tank at the U.S. Coast Guard Fire and Safety Test Detachment in Mobile, Alabama, utilizing ASTM F-20 draft standards. Six different fire-resistant containment booms were used. Three of the six were modified designs of booms used in the first series of tests. The tests in this series were designed to address issues raised in the first series, namely the location of heat fluxes and thermocouples, and the protocol for water-cooled booms. The results of the second series of tests are discussed and compared to the first. Strengths and weaknesses of the test protocol and other possible improvements are also discussed. 5 refs., 5 tabs., 7 figs

  3. Conceptual design of a flying boom for air-to-air refueling of passenger aircraft

    Science.gov (United States)

    Timmermans, Ir. H. S.; La Rocca, ir. G., Dr.

    2014-10-01

    This paper describes the conceptual development of a flying boom for air-to-air refuelingof passenger aircraft. This operational concept is currently evaluated within the EC project RECREATE as a possible means to achieve significant increase in overall fuel efficiency. While in military aviation aerial refueling is performed with the tankerflyingahead and above the receiver aircraft, in case of passenger aircraft, safety, cost and comfort criteria suggest to invert the set up. This unconventional configuration would require a different refueling boom, able to extend from the tanker towards the cruiser, against wind and gravity. Amultidisciplinary design optimization framework was set up to size and compare various boom design solutions free of structural divergence and sufficientlycontrollable and with minimum values of weight and drag. Oneconcept, based on an innovative kinematic mechanism, was selected for its ability to meet all design constraints, with weight and drag values comparable to conventional boom designs.

  4. Sonic Boom Vibro-Acoustic Simulations using Multiple Point Sources Project

    Data.gov (United States)

    National Aeronautics and Space Administration — AVEC proposes an innovative concept for the evaluation of human response studies to sonic booms inside realistic structures. The approach proposed is to simulate...

  5. The branch banking boom in Illinois: a byproduct of restrictive branching laws

    OpenAIRE

    Erin Davis; Tara Rice

    2007-01-01

    What’s behind the boom in bank branches across Illinois, particularly in Chicago? The authors explore the history of branch banking within the state and across the nation to help explain this recent trend and discuss its future implications.

  6. Integration of Engine, Plume, and CFD Analyses in Conceptual Design of Low-Boom Supersonic Aircraft

    Science.gov (United States)

    Li, Wu; Campbell, Richard; Geiselhart, Karl; Shields, Elwood; Nayani, Sudheer; Shenoy, Rajiv

    2009-01-01

    This paper documents an integration of engine, plume, and computational fluid dynamics (CFD) analyses in the conceptual design of low-boom supersonic aircraft, using a variable fidelity approach. In particular, the Numerical Propulsion Simulation System (NPSS) is used for propulsion system cycle analysis and nacelle outer mold line definition, and a low-fidelity plume model is developed for plume shape prediction based on NPSS engine data and nacelle geometry. This model provides a capability for the conceptual design of low-boom supersonic aircraft that accounts for plume effects. Then a newly developed process for automated CFD analysis is presented for CFD-based plume and boom analyses of the conceptual geometry. Five test cases are used to demonstrate the integrated engine, plume, and CFD analysis process based on a variable fidelity approach, as well as the feasibility of the automated CFD plume and boom analysis capability.

  7. An ElectroAdhesive "Stick Boom" for Mars Sample Return Orbiting Sample Capture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Electroadhesive "Sticky Boom", an innovative method for rendezvous and docking, is proposed for the Orbiting Sample Capture (OSC) portion of the Mars...

  8. A NASTRAN investigation of simulated projectile damage effects on a UH-1B tail boom model

    Science.gov (United States)

    Futterer, A. T.

    1980-01-01

    A NASTRAN model of a UH-1B tail boom that had been designed for another project was used to investigate the effect on structural integrity of simulated projectile damage. Elements representing skin, and sections of stringers, longerons and bulkheads were systematically deleted to represent projectile damage. The structure was loaded in a manner to represent the flight loads that would be imposed on the tail boom at a 130 knot cruise. The deflection of four points on the rear of the tail boom relative to the position of these points for the unloaded, undamaged condition of the tail boom was used as a measure of the loss of structural rigidity. The same procedure was then used with the material properties of the aluminum alloys replaced with the material properties of T300/5208 high strength graphite/epoxy fibrous composite material, (0, + or - 45, 90)s for the skin and (0, + or - 45)s for the longerons, stringers, and bulk heads.

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

    International Nuclear Information System (INIS)

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

  10. Iodide uptake by negatively charged clay interlayers?

    International Nuclear Information System (INIS)

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

  11. 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...

  12. Design optimization of an articulated boom for NET in-vessel handling unit

    International Nuclear Information System (INIS)

    In-vessel components of fusion reactors must be remotely replaceable. The necessary handling will be performed from inside the torus by means of work units. A major problem is to carry the work units inside the torus. One concept to solve this problem is to use an in-vessel handling unit based on an articulated boom. It is supported outside the torus and enters the torus through an entry port. Additional supports are not available. Then the work unit (manipulator unit, diverter handling unit or antenna handling unit), attached to the end-frame of the boom, is able to reach any point inside the torus. Therefore the boom consists of eleven links connected by yaw joints. Its stretched (unfolded) length is about 25 m. Due to the scissor type of design, the boom can be folded such that the required area to store it is only 10.25 x 3.2 m. The cross-sections of the links (except those staying outside the torus) are 350 x 1350 mm. In order to allow easy repair and exchange, the drive mechanisms for the joints and the necessary cable are located above the links. The resulting overall dimensions are such that the boom may pass the entry port having an opening of 650 x 1900 mm. The maximum load at the tip of the boom is about 3900 kg. It consists of the maximum payload of 1000 kg (which is the load of a diverter plate plus gripper) and the load of the diverter handling unit of 29000 kg. The design of the boom such that the stresses and strains are within allowed limits turned out to be a difficult task. It led to a boom dead load of about 25000 kg which is 25-times the payload. In this paper the structural mechanics assessment to find an appropriate design is described

  13. Credit Booms and Busts in Emerging Markets: The Role of Bank Governance and Risk Managment

    OpenAIRE

    Alin Marius ANDRIES; Brown, Martin

    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, handcollected 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 ban...

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

    OpenAIRE

    Brown, Martin; Andries, Alin

    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...

  15. A Novel Telescopic Boom Deployment System for Use in Upper Atmosphere Research

    OpenAIRE

    Wylie, Mark; Duffy, Paul; Vather, Dinesh; Keegan, John; Curran, Stephen

    2010-01-01

    Typical measurement probe deployment systems on sounding rockets employ hinged booms which extend the probes away from the rocket. This configuration often has a significant mass and may require a considerable amount of the rocket’s valuable payload volume. In an effort to reduce both mass and volume, the DIT Space Research Group have designed a light weight carbon fibre telescopic boom system, compatible with measurement probes commonly used in upper atmosphere research. Our design has been ...

  16. From boom to bust: how different has microfinance been from traditional banking?

    OpenAIRE

    Wagner, Charlotte

    2010-01-01

    This paper presents an in-depth analysis of developments in the microfinance sector before and after the Lehman Brothers collapse in 2008 by comparing them with developments in traditional banking sectors of emerging market economies and developing countries. The findings indicate that microfinance has been part of the same credit boom observed in the traditional banking sector. Moreover, as in the traditional banking sector, the boom was fostered by substantial inflows of foreign capital. Th...

  17. NOFI oil Vee-Sweep and extension boom test at OHMSETT

    International Nuclear Information System (INIS)

    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

  18. Improvement Of Spray Deposit Homogeneity Using A Pwm Spray Controller To Compensate Horizontal Boom Speed Variations

    OpenAIRE

    Lebeau, Frédéric; El Bahir, L.; Destain, Marie-France; Kinnaert, M.; Hanus, R.

    2004-01-01

    Longitudinal spray distribution is mainly affected by the horizontal speed variations of the nozzles. Manufacturers classically try to reduce unwanted nozzles movements using horizontal boom suspension but these methods have performance and price limitations. This paper describes a spray controller aiming to compensate the effect of the horizontal boom movements on the spray deposits homogeneity. The controller is based on three main components: a control law describing the relati...

  19. Of bubbles and bankers: The impact of financial booms on labor markets

    OpenAIRE

    Tobias Wuergler

    2009-01-01

    This paper studies the effect of financial booms and extreme asset valuations on the relative demand for skills and the wage structure. The substantial rise in wage inequality in the U.S. since the late 1970s has been accompanied by a major expansion of financial services, a series of asset bubbles, and rising relative wages and relative education in the financial industry. I motivate and develop a theoretical framework where financial institutions benefit from financial booms and asset bubbl...

  20. On Resource Booms and Busts: Some Aspects of the Dutch Disease in Six Developing Economies

    OpenAIRE

    Cassing, James H.; Wells, Jerome C.; Zamalloa, Edgar L.

    1987-01-01

    This paper examines changes in national product and net welfare over resource boom and bust cycles in six developing economies: Chile, Zaire, Zambia, Indonesia, Mexico, and Nigeria. The authors find that changes in the terms of trade account for over 25 to 33 percent of the changes in net welfare, that capital movements usually act procyclically, and that a fall in the growth rate of real product accompanies the end of the resource boom. They also examine changes in the government's share in ...

  1. SUSTAINABILITY IN FISCAL POLICY IN BOOM AND RECESSION-THE CASE OF ROMANIA

    OpenAIRE

    Mihaela GÖNDÖR

    2013-01-01

    This paper examines the interrelated aspects of the recent economic and fiscal crisis – such as the GDP growth, budgetary deficit and public debt, fiscal policy and austerity measures in Romania by comparing the different effects caused by different fiscal policies within a boom period and a downturn period. The paper reveals that the boom period is characterized by tax rate cuts and rising of expenditures and the downturn period, by the increasing of fiscal burden and sharply reducing the go...

  2. Ultrasound guided supraclavicular block.

    LENUS (Irish Health Repository)

    Hanumanthaiah, Deepak

    2013-09-01

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

  3. An investigation into the effect of playback environment on perception of sonic booms when heard indoors

    Science.gov (United States)

    Carr, Daniel; Davies, Patricia

    2015-10-01

    Aircraft manufacturers are interested in designing and building a new generation of supersonic aircraft that produce shaped sonic booms of lower peak amplitude than booms created by current supersonic aircraft. To determine if the noise exposure from these "low"booms is more acceptable to communities, new laboratory testing to evaluate people's responses must occur. To guide supersonic aircraft design, objective measures that predict human response to modified sonic boom waveforms and other impulsive sounds are needed. The present research phase is focused on understanding people's reactions to booms when heard inside, and therefore includes consideration of the effects of house type and the indoor acoustic environment. A test was conducted in NASA Langley's Interior Effects Room (IER), with the collaboration of NASA Langley engineers. This test was focused on the effects of low-frequency content and of vibration, and subjects sat in a small living room environment. A second test was conducted in a sound booth at Purdue University, using similar sounds played back over earphones. The sounds in this test contained less very-low-frequency energy due to limitations in the playback, and the laboratory setting is a less natural environment. For the purpose of comparison, and to improve the robustness of the model, both sonic booms and other more familiar transient sounds were used in the tests. The design of the tests and the signals are briefly described, and the results of both tests will be presented.

  4. Long-term effects of simulated sonic booms on hearing in rhesus monkeys

    Science.gov (United States)

    Reinis, S.; Weiss, D. S.; Featherstone, J. W.; Tsaros, C.

    1987-03-01

    Two monkeys of the species Macaca mulatta were exposed at 1 min intervals to five simulated sonic booms lasting 200 ms at 200 Pa overpressure with a 10 ms rise time. Another group of five monkeys of the same species were exposed to 100 booms. Their hearing thresholds were tested 24 hours, two weeks, one month, two months, four months and six months later. In one animal exposed to five booms, changes of the hearing thresholds were observed 24 hours following the exposure, but not later. All five animals exposed to 100 sonic booms had threshold shifts in the high-frequency range 24 hours following the exposure. Of the three animals followed for the full period of six months, one recovered completely. In the two others, threshold shifts were still observed in the high frequency range. Histological examination revealed destruction of the organ of Corti in the basal turn of the cochlea. These data indicate that there is individual variability in the extent of the damage to the inner ear by the sonic boom (and, perhaps, by other types of impulsive noise). These data also indicate that there is a possibility of similar damage to human inner ears exposed either to sonic booms or to other types of impulsive noise, and that it may go undetected for a long time because the high-frequency hearing defect, over 8 kHz, may be overlooked when routine audiometric methods are used.

  5. Potential and viscous flows past an oil boom: The instability problem

    International Nuclear Information System (INIS)

    An important problem in oil spill containment by booms is the instability of the oil-water interface at the boom. This instability, which represents the conditions under which oil can escape under the boom, is investigated. Both the potential and viscous-flow models for thin slicks in two-dimensions are developed. Analytical instability formulas are derived using the velocity potentials for attached and detached flows due to uniform current past a flat plate in finite and infinite water depths. To understand the effect of viscosity on the instability criterion, the full Navier-Stokes equations are solved by the fractional-step method in time domain to determine the pressure gradients along the boom. The numerically obtained viscous instability criterion is then compared with the potential-flow and experimentally determined instability criteria. The results show that the viscous flow model predicts a larger region of stability. It is numerically discovered from the instability criterion that the oil droplets at the boom, between the free surface and down to about 40% of the boom height can never escape, regardless of the current strength. It is also shown that the instability criterion depends weakly on the high Reynolds number. Reanalysis of the previous experimental data confirm these numerical findings

  6. The calculation of the instability criterion for a uniform viscous flow past an oil boom

    International Nuclear Information System (INIS)

    An important problem in oil spill containment by booms is the instability of the oil-water interface at the boom. This instability, which represents the conditions under which oil can escape under the boom, is investigated. A viscous flow model for thin slicks in two dimensions is developed. To understand the effect of viscosity on the instability criterion, the full Navier-Stokes equations are solved by the fractional-step method in time-domain to determine the pressure gradients along the boom. The numerically obtained viscous instability criterion is then compared with the potential flow and experimentally determined instability criteria. Analytical instability formulas for potential flows are based on the velocity potentials for attached and detached flows due to uniform current past a flat plate in finite and infinite water depths. The results show that the viscous flow model predicts a larger region of stability. It is numerically determined from the instability criterion that the oil droplets at the boom between the free surface and down to about 40 percent of the boom height can never escape, regardless of the current strength. It is also shown that the instability criterion depends weakly on the high Reynolds number. Reanalysis of the available experimental data confirms these findings

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

  9. Electric Field Wire Boom System and instrument for CubeSats

    Science.gov (United States)

    Stromberg, E. M.; Burr, S.; Hui, D.; Swenson, C.

    2009-12-01

    The viability of CubeSats as meaningful platforms for observing the upper atmosphere depends upon the development of suitable scientific instrumentation. One of the most fundamental parameters to observe in the space environment is the electric fields which drive the motions of the plasma in the ionosphere and magnetosphere. A well known technique for observing electric fields is the double probe with sensors deployed several meters from the space vehicle. A compact wire boom system, deploying sensors from opposite sides of a spinning CubeSat has been developed at Utah State University. We present the development of a 10 meter tip-to-tip wire boom system to deploy four 1-cm spherical double probe sensors. The wire boom mechanism consists of a spool which is actuated with a small non-magnetic, piezoelectric motor, to control deployment. The wire boom and electric field instrument is 1.25cm high and fits a standard 10 x10 cm CubeSat cross section. The spherical sensors at the end of the wire booms are gold plated to minimize geometric work function dissimilarities and to provide surface electrical stability. We present an analysis of the expected performance and lifetime of this boom in low Earth orbit. The proposed design permits the measurement of the two-dimensional DC-electric field determined only by the spacecraft velocity and the instrument sampling rate.

  10. Dehydration-induced luminescence in clay minerals

    Science.gov (United States)

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

    1981-01-01

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

  11. Clay smear: Review of mechanisms and applications

    Science.gov (United States)

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

    2016-05-01

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

  12. Geomechanics of clays for radioactive waste disposal

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2012-04-01

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

  14. Active containment systems incorporating modified pillared clays

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-31

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

  15. Clays and other minerals in prebiotic processes

    Science.gov (United States)

    Paecht-Horowitz, M.

    1984-01-01

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

  16. Characterization of a few Mexican clays

    International Nuclear Information System (INIS)

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

  17. 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...

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

    International Nuclear Information System (INIS)

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

  19. Optimisation of a vertical spray boom for greenhouse spraying applications.

    Science.gov (United States)

    Nuyttens, D; Windey, S; Braekman, P; De Moor, A; Sonck, B

    2003-01-01

    The European Crop Protection Association (ECPA) and CLO-DVL joined forces in a project to stimulate a safe use of pesticides in Southern European countries. CLO-DVL optimised a method with mineral chelates to evaluate deposition tests. This quantitative method to evaluate spray deposits and to check spray distributions is used to assess two novel spraying techniques. Deposition tests with water-sensitive paper and mainly with the manganese and molybdenum chelates as tracer elements were performed with a manually pulled trolley and a motorised vehicle both equipped with vertical spray booms. Filter papers were attached to the tomato and pepper plants at several heights to obtain an indication of the spray distribution in the crop. Particular attention was paid to the effect on the spray distribution of the vertical nozzle distance (35 cm vs. 50 cm) and the spray distance to the crop. The tests proved that a nozzle spacing of 35 cm delivers a much better spray distribution than one of 50 cm. The optimal spray distance for flat fan nozzles with a spray angle of 80 degrees and a nozzle spacing of 35 cm is about 30 cm. PMID:15151329

  20. Boom, Bust and Beyond: Arts and Sustainability in Calumet, Michigan

    Directory of Open Access Journals (Sweden)

    Richelle Winkler

    2016-03-01

    Full Text Available Cycles of boom and bust plague mining communities around the globe, and decades after the bust the skeletons of shrunken cities remain. This article evaluates strategies for how former mining communities cope and strive for sustainability in the decades well beyond the bust, using a case study of Calumet, Michigan. In 1910, Calumet was at the center of the mining industry in the Upper Peninsula of Michigan, but in the century since its peak, mining employment steadily declined until the last mine closed in 1968, and the population declined by over 80%. This paper explores challenges, opportunities, and progress toward sustainability associated with arts-related development in this context. Methods are mixed, including observation, interviews, document review, a survey, and secondary data analysis. We follow Flora and Flora’s Community Capitals Framework to analyze progress toward sustainability. Despite key challenges associated with the shrunken city context (degraded tax base, overbuilt and aging infrastructure, diminished human capital, and a rather limited set of volunteers and political actors, we find the shrunken city also offers advantages for arts development, including low rents, less risk of gentrification, access to space, and political incentive. In Calumet, we see evidence of a spiraling up pattern toward social sustainability resulting from arts development; however impacts on environmental and economic sustainability are limited.

  1. Global booms and busts: how is Brazil's middle class faring?

    Directory of Open Access Journals (Sweden)

    Jan Peter Wogart

    2010-09-01

    Full Text Available Brazil's Post War economic history has been marked by inflationary booms and busts, which kept large parts of the population poor, as income distribution remained highly skewed, and most governments failed to put enough efforts and resources into education and health. That seems to have changed recently, as an increasing number of studies have shown considerable advances in the incomes of the lower and the middle classes. This essay examines those findings and puts them into a historical perspective, discussing earlier attempts and hopes of Brazilian policy makers to advance the welfare of the population. It concludes that while the last fifteen years have been remarkable for the country to achieve macroeconomic stability and while the increasing efforts of supporting the poor seemed to have been moving income distribution slowly towards a more equal level, there is still a long way to go. The 2008 world financial crisis also hit Brazil hard, but the recovery has been smoother and faster than in any OECD country. The impact of the current crisis may provide a good test as to the robustness of the previous trends to further the wellbeing of the poor and the middle class

  2. 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.

  3. 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

  4. Mineral Acquisition from Clay by Budongo Forest Chimpanzees

    OpenAIRE

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

    2015-01-01

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

  5. 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.

  6. Comparative thermal analysis of the space station Freedom photovoltaic deployable boom structure using TRASYS, NEVADA, and SINDA programs

    Energy Technology Data Exchange (ETDEWEB)

    Baumeister, J.F.; Beach, D.E.; Armand, S.C.

    1989-07-01

    The proposed Space Station Photovoltaic Deployable Boom was analyzed for operating temperatures. The boom glass/epoxy structure design needs protective shielding from environmental degradation. The protective shielding optical properties (solar absorptivity and emissivity) dictate the operating temperatures of the boom components. The Space Station Boom protective shielding must also withstand the effects of the extendible/retractable coiling action within the mast canister. A thermal analysis method was developed for the Space Station Deployable Boom to predict transient temperatures for a variety of surface properties. The modeling procedures used to evaluate temperatures within the boom structure incorporated the TRASYS, NEVADA, and SINDA thermal analysis programs. Use of these programs led to a comparison between TRASYS and NEVADA analysis methods. Comparing TRASYS and NEVADA results exposed differences in the environmental solar flux predictions.

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

    Science.gov (United States)

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

    2016-02-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  9. Design of Experiments for Both Experimental and Analytical Study of Exhaust Plume Effects on Sonic Boom

    Science.gov (United States)

    Castner, Raymond S.

    2009-01-01

    Computational fluid dynamics (CFD) analysis has been performed to study the plume effects on sonic boom signature for isolated nozzle configurations. The objectives of these analyses were to provide comparison to past work using modern CFD analysis tools, to investigate the differences of high aspect ratio nozzles to circular (axisymmetric) nozzles, and to report the effects of under expanded nozzle operation on boom signature. CFD analysis was used to address the plume effects on sonic boom signature from a baseline exhaust nozzle. Nearfield pressure signatures were collected for nozzle pressure ratios (NPRs) between 6 and 10. A computer code was used to extrapolate these signatures to a ground-observed sonic boom N-wave. Trends show that there is a reduction in sonic boom N-wave signature as NPR is increased from 6 to 10. As low boom designs are developed and improved, there will be a need for understanding the interaction between the aircraft boat tail shocks and the exhaust nozzle plume. These CFD analyses will provide a baseline study for future analysis efforts. For further study, a design of experiments has been conducted to develop a hybrid method where both CFD and small scale wind tunnel testing will validate the observed trends. The CFD and testing will be used to screen a number of factors which are important to low boom propulsion integration, including boat tail angle, nozzle geometry, and the effect of spacing and stagger on nozzle pairs. To design the wind tunnel experiment, CFD was instrumental in developing a model which would provide adequate space to observe the nozzle and boat tail shock structure without interference from the wind tunnel walls.

  10. Block clustering with collapsed latent block models

    OpenAIRE

    Wyse, Jason; Friel, Nial

    2010-01-01

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

  11. Discrete analysis of clay layer tensile strength

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  13. Radionuclides sorption in clay soils

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

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

    2012-01-01

    either air-dried or rewetted to −100 hPa matric potential. Tensile strength of 1- to 2-, 2- to 4-, 4- to 8-, and 8- to 16-mm air-dried aggregates was calculated from their compressive strength, and soil friability estimated from the strength–volume relation. Crop rotation characteristics gave only minor......Soil organic carbon (OC) influences clay dispersibility, which affects soil tilth conditions and the risk of vertical migration of clay colloids. No universal lower threshold of OC has been identified for satisfactory stabilization of soil structure. We tested the concept of clay saturation with OC...... as a predictor of clay dispersibility and soil friability. Soil was sampled 3 yr in a field varying in clay content (∼100 to ∼220 g kg−1 soil) and grown with different crop rotations. Clay dispersibility was measured after end-over-end shaking of field-moist soil and 1- to 2-mm sized aggregates...

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

    Directory of Open Access Journals (Sweden)

    Karpiński B.

    2015-03-01

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

  16. A preliminary study on titanium-clay interactions

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  18. A new evaluation of noise metrics for sonic booms using existing data

    Science.gov (United States)

    Loubeau, Alexandra; Naka, Yusuke; Cook, Brian G.; Sparrow, Victor W.; Morgenstern, John M.

    2015-10-01

    An evaluation of noise metrics for predicting human perception of sonic booms was performed. Twenty-five metrics were chosen from standards and from the literature in an effort to include all potentially relevant metrics. Three different datasets of sonic boom waveforms and associated human response were chosen to span a variety of signals, including traditional N-waves with various shock shapes and rise times, and predicted waveforms from designs of low-boom aircraft for a variety of aircraft sizes. These datasets were derived from laboratory studies conducted in sonic boom simulators at NASA Langley Research Center and JAXA. Simulations of booms experienced in both outdoor and indoor environments were included by using different facilities at NASA or modifications to facility configurations at JAXA. American and Japanese test subjects participated at NASA and JAXA, respectively. Ratings of loudness using a magnitude estimation technique and ratings of annoyance using a category line scaling method are included. The evaluation consists of linear correlations of human response data with the objective noise metrics. Results are presented for each study, and eight metrics are suggested for further analysis.

  19. Sonic booms produced by US Air Force and US Navy aircraft: Measured data

    Science.gov (United States)

    Lee, R. A.; Downing, J. M.

    1991-01-01

    A sonic measurement program was conducted at Edwards Air Force Base. Sonic boom signatures, produced by F-4, F-14, F-15, F-16, F-18, F-111, SR-71, and T-38 aircraft, were obtained under the flight track and at various lateral sites which were located up to 18 miles off-track. Thirteen monitors developed by Det 1 AL/BBE were used to collect full sonic boom waveforms, and nine modified dosimeters were used to collect supplemental peak overpressures and the C-weighted Sound Exposure Levels (CSEL) for 43 near steady supersonic flights of the above United States Air Force and United States Navy aircraft. This report describes the measured database (BOOMFILE) that contains sonic boom signatures and overpressures, aircraft tracking, and local weather data. These measured data highlight the major influences on sonic boom propagation and generation. The data from this study show that a constant offset of 26 from the peak overpressure expressed in dB gives a good estimate of the CSEL of a sonic boom.

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

    International Nuclear Information System (INIS)

    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.)

  1. Study of radionuclide migration in clay formations

    International Nuclear Information System (INIS)

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

  2. Moessbauer firing study of Lishan clay

    International Nuclear Information System (INIS)

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

  3. Interaction of Auramine O with montmorillonite clays

    International Nuclear Information System (INIS)

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

  4. Aspects of clay/concrete interactions

    International Nuclear Information System (INIS)

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

  5. Surface geochemistry of the clay minerals

    OpenAIRE

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

    1999-01-01

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

  6. Nanomechanical characterization of clay micro flocs

    OpenAIRE

    Zhang, Guoping; Yin, Hang; Reed, Allen

    2014-01-01

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

  7. Dynamic properties of composite cemented clay

    Institute of Scientific and Technical Information of China (English)

    蔡袁强; 梁旭

    2004-01-01

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

  8. Effects of subsurface cavity expansion in clays

    OpenAIRE

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

    2007-01-01

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

  9. The aeration of clay soils in cricket

    OpenAIRE

    Parsons, Simon A.

    2012-01-01

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

  10. Clay-Bacteria Systems and Biofilm Production

    Science.gov (United States)

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

    2007-12-01

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

  11. Water vapour permeability of clay bricks

    OpenAIRE

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

    2003-01-01

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

  12. Measuring and Modeling the Plasticity of Clays

    OpenAIRE

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

    2010-01-01

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

  13. Incomplete block designs

    CERN Document Server

    Dey, Aloke

    2010-01-01

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

  14. Seismo-acoustic effects of sonic booms on archeological sites, Valentine Military Operations Area

    Science.gov (United States)

    Battis, J. C.

    1983-11-01

    Seismo-acoustic recordings of sonic booms were made at two sites in the Valentine Military Operations Areas (MOA). Each location was selected as representative of a class of significant archeological sites found within the MOA. These studies indicate that sonic booms are unlikely to cause damage to the archeological finds. The expected motions are, at worst, 8 percent of the limits set by strict blasting codes and comparable to velocities that could be produced by local earthquakes which have occurred in the Valentine area. At these levels of motion, competent rock will be unaffected by the transmission of seismic waves. The predicted velocity levels are unlikely to initiate either fracture or spalling in rocks. However, it is possible that in rocks where natural meteorological action has initiated these erosive mechanisms the sonic boom induced motion accelerate the processes to some small, and probably insignificant, degree.

  15. 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.

  16. 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.

  17. Stress analysis of an articulated boom for in-vessel-handling of fusion reactors

    International Nuclear Information System (INIS)

    Due to the high radioactivity levels, in-vessel maintenance work in the plasma chamber of a tokamak fusion machine can be done only by remote handling equipment, which is introduced into the torus-type plasma chamber by means of an articulated boom. The remote handling units have to be operated without any support provided for at the walls of the plasma chamber. A new articulated boom design is currently developed in the KfK for the NET project. This device is to bear at its tip working loads of up to 3900 kg (max. weight of remote handling equipment 2900 kg, of interchangeable components 1000 kg). In order to allow as precise manipulation as possible, the degree of sogging of the boom tip under its own load or under the working load has to be kept as small as possible. (orig./DG)

  18. 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.

  19. 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.

    1991-05-01

    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.

  20. Study on thermally induced vibration of flexible boom in various thermal environments of vacuum chamber

    Science.gov (United States)

    Kong, Changduk; Oh, Kyung-Won; Park, Hyun-Bum; Sugiyama, Y.

    2005-02-01

    In order to simulate the thermally-induced vibration phenomenon of the flexible thin boom structure of the spacecraft such as the thin solar panel and the flexible cantilever with the attached tip mass in space, the thermally-induced vibration including thermal flutter of the flexible thin boom with the concentrated tip mass was experimentally investigated at various thermal environments using a heat lamp and both vacuum and air condition using the vacuum chamber. In this experimental study, divergence speed, natural frequency and thermal strains of the thermally-induced vibration were comparatively evaluated at various thermal environment conditions. Finally the thermally-induced vibration of the flexible boom structure of the earth orbit satellite in solar radiation environment from the earth eclipse region including umbra and penumbra was simulated using the vacuum chamber and power control of the heating lamp.

  1. Swelling clay pellets. Elaboration and characterization

    International Nuclear Information System (INIS)

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

  2. Operational comparison of two types of tractor sprayers (microner and boom-type against wheat crop weeds

    Directory of Open Access Journals (Sweden)

    M Hamid

    2015-09-01

    other one was flowage nozzle and they were compared with control treatment. Experiment design was Randomized Completed blocks Design (RCBD with seven replications. Parameters such as spraying quality, diameter, volume mean diameter and numerical mean of droplets, spray quality factor, the percentage of crash crop, weeds dry weight and number, percentage of weed control and the drift were measured. The results were compared with a control treatment. For comparative tests between the sprayers, the measured parameters were compared with each other using SAS software. Results and Discussion: Volume mean diameter and numerical mean diameter in tractor mounted microner sprayer with medium and low speed rotation disk treatment and also tractor mounted boom sprayer with Italian fan nozzle treatment were metered 162.5, 461 and 635.5 micron, and 138.5, 355 and 452.5 micron, respectively. Volume mean diameter related to numerical mean diameter was obtained to be 1.17 and 1.3 for tractor mounted microner sprayer with medium and low levels of speed rotation disk, and 1.4 for tractor mounted boom sprayer with Italian fan nozzle, respectively. Whenever the spray quality coefficient is closer to one, the spray quality is better. So microner sprayer treatment with 1.17 coefficient has the best spray quality. The results about weeds control numbers showed all treatments had significant difference with control treat in 1% levels (Table 3. Evaluating all treatment results showed the flowage nozzle with 22.57 weeds number and 27.26 g. weeds dry weight had significant difference with other treatments in 1% levels that was the best operation (Table 4. In comparison of sprayers’ technical evaluation, all treatments had significant difference in 1% levels, so the flowage nozzle with 191.66 l.ha solution consumption and microner treatment with medium speed rotation disk with 44.38 l.ha solution consumption were the most and the least treatments. And they have significant difference in 1

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

    OpenAIRE

    Al Mohandis, Ahmed A. [احمد عبد القادر المهندس

    1993-01-01

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

  4. Development and Characterisation of Nanoclays from Indian Clays

    OpenAIRE

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

    2008-01-01

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

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

    OpenAIRE

    Wilson Ian Richard

    1998-01-01

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

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

    Science.gov (United States)

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

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

  7. NMR imaging and cryoporometry of swelling clays

    Science.gov (United States)

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

    2010-05-01

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

  8. Postural heart block.

    OpenAIRE

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

    1980-01-01

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

  9. The American Environmental Movement's Lost Victory: The Fight against Sonic Booms.

    Science.gov (United States)

    Suisman, David

    2015-11-01

    Political contestation over sound can take many forms, with profound consequences for the aural environment. One example is found in the battles over the sonic booms associated with the US government's supersonic transport (SST) program in the 1960s and early 1970s--a program that had it been realized, would have filled the everyday soundscape with thunderous sonic blasts. This article analyzes the individuals and groups who mobilized against sonic booms and the SST and the activists' unlikely success over the SST in 1971. Today, this victory stands as an important, if largely forgotten, victory of the early environmental movement. PMID:26720994

  10. The Changing Nature of Irish Wage Inequality from Boom to Bust.

    OpenAIRE

    Holton, Niamh; O'Neill, Donal

    2015-01-01

    The dramatic change in economic conditions in Ireland over the last 10 years provides an opportunity to examine the impact of large macroeconomic shocks on inequality. We analyse wage inequality in Ireland from the height of an economic boom, through a very deep recession, to the start of a recovery. In keeping with previous work we find that dispersion in wages increased towards the height of the boom, driven largely by rising returns to skills. However, the economic crisis of 2008-2013 was ...

  11. Specialized CFD Grid Generation Methods for Near-Field Sonic Boom Prediction

    Science.gov (United States)

    Park, Michael A.; Campbell, Richard L.; Elmiligui, Alaa; Cliff, Susan E.; Nayani, Sudheer N.

    2014-01-01

    Ongoing interest in analysis and design of low sonic boom supersonic transports re- quires accurate and ecient Computational Fluid Dynamics (CFD) tools. Specialized grid generation techniques are employed to predict near- eld acoustic signatures of these con- gurations. A fundamental examination of grid properties is performed including grid alignment with ow characteristics and element type. The issues a ecting the robustness of cylindrical surface extrusion are illustrated. This study will compare three methods in the extrusion family of grid generation methods that produce grids aligned with the freestream Mach angle. These methods are applied to con gurations from the First AIAA Sonic Boom Prediction Workshop.

  12. Calculation program for the analysis of the performance of boom-type reclaimers

    Energy Technology Data Exchange (ETDEWEB)

    Bergonzoli, A.; Ferretti, C.

    1986-04-01

    The paper describes a calculation program which allows the performance of a slewing boom bucket wheel reclaimer to be thoroughly analysed. The features required for the correct sizing of the structural and operational components can be evaluated and the optimum operating criteria under the most frequent operating conditions can be defined. Topics covered are: general description of the calculation program including reclaiming rate analysis and power requirement analysis; and program control and description of results including representation of results with and without boom slewing, and representation of statistical parameters.

  13. Simplified sonic-boom prediction. [using aerodynamic configuration charts and calculators or slide rules

    Science.gov (United States)

    Carlson, H. W.

    1978-01-01

    Sonic boom overpressures and signature duration may be predicted for the entire affected ground area for a wide variety of supersonic airplane configurations and spacecraft operating at altitudes up to 76 km in level flight or in moderate climbing or descending flight paths. The outlined procedure relies to a great extent on the use of charts to provide generation and propagation factors for use in relatively simple expressions for signature calculation. Computational requirements can be met by hand-held scientific calculators, or even by slide rules. A variety of correlations of predicted and measured sonic-boom data for airplanes and spacecraft serve to demonstrate the applicability of the simplified method.

  14. News, Intermediation Efficiency and Expectations-driven Boom-bust Cycles

    OpenAIRE

    Christopher M. Gunn; Alok Johri

    2011-01-01

    The years leading up to the "great recession" were a time of rapid innovation in the financial industry. This period also saw a fall in interest rates, and a boom in liquidity that accompanied the boom in real activity, especially investment. In this paper we argue that these were not unrelated phenomena. The adoption of new financial products and practices led to a fall in the expected costs of intermediation which in turn engendered the flood of liquidity in the financial sector, lowered in...

  15. 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

  16. Gas, gas, gas... discoveries and developments booming worldwide

    International Nuclear Information System (INIS)

    Deep water exploration is yielding more than billion barrel oil fields. Unocal's 3 May discovery of 2-3 Tcf of gas in its Kutei block of Indonesia marks the first major discovery of natural gas in the deep water frontier: Wildcats Gula and Gada were drilled in over 1800 m of water as part of an aggressive search for gas instigated by Unocal last year. The author makes a survey of gas exploration and development throughout the world. (author)

  17. Analysis and Experiment of Residual Load Sway Suppression in Rotary Crane Systems Using Simple Trajectory for Horizontal Boom Motion

    Science.gov (United States)

    Ouyang, Huimin; Uchiyama, Naoki; Sano, Shigenori

    To suppress two-dimensional load sway caused by the horizontal boom motion of a rotary crane, both horizontal and vertical boom motions are generally used. However, it would be more energy efficient and safer if a control scheme is developed that only used horizontal boom motion, eliminating the need for any vertical boom motion. In addition, if we can suppress load sway without the need to measure it, reduction in the cost of sensors can be achieved. Furthermore, use of simple velocity trajectory patterns such as a trapezoidal velocity pattern and an S-curve acceleration/deceleration pattern, which are widely used in industrial automation systems, may provide cost-effective implementation of controllers. This study examines the analytical conditions for a simple S-curve trajectory of horizontal boom motion to suppress residual load sway without sensing it. Numerical simulation and experimental results demonstrate the effectiveness of the proposed conditions.

  18. Oil-slick instability near an oil boom: The influence of free-slip and exact free-surface conditions

    International Nuclear Information System (INIS)

    In the event of an oil spill, oil booms are often used to contain the oil before attempting to skim the oil by using oil-skimmers. Under certain conditions, the oil droplets can leave the oil slick and enter the water. A simple balance of hydrodynamic forces on such a droplet results in an instability criterion which determines whether the droplets will be swept past the boom or not. This criterion depends on the pressure gradient along the boom. In this study, the solution of viscous flow past an oil boom problem by the fractional-step method in a curvilinear coordinate system is used to calculate the pressure gradient and to study the effectiveness of oil-containment by booms. The influence of approximate free-surface conditions, such as rigid-lid no-slip, rigid-lid free-slip, and the exact free-surface condition on the instability criterion is investigated

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

    Science.gov (United States)

    Colman, Steven M.

    1982-01-01

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

  20. 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.