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Sample records for sand columns electronic

  1. Residual diesel measurement in sand columns after surfactant/alcohol washing

    International Nuclear Information System (INIS)

    Martel, R.; Gelinas, P.J.

    1996-01-01

    A new simple gravimetric technique has been designed to determine residual oil saturation of complex hydrocarbon mixtures (e.g., diesel) in sand column experiments because reliable methods are lacking. The He/N 2 technique is based on drying of sand columns by circulating helium gas to drag oil droplets in a cold trap (liquid nitrogen). With this technique, residual diesel measurement can be performed easily immediately after alcohol/surfactant washing and in the same lab. For high residual diesel content in Ottawa sand (25 to 30 g/kg), the technique is much more accurate (± 2% or 600 mg/kg) than the standard analytical methods for the determination of mineral oil and grease. The average relative error on partial diesel dissolution in sand column estimated after alcohol/surfactant flooding (residual saturation of 10 to 15 g/kg) is as low as 5%. The precision of the He/N 2 technique is adequate to compare relative efficiency of washing solutions when partial extraction of residual oil in Ottawa sand columns is performed. However, this technique is not adapted for determination of traces of oil in sediment or for environmental control of contaminated soils. Each diesel determination by the He/N 2 technique costs less than $8 in chemical products (helium and liquid nitrogen). A simple laboratory drying setup can be built for less than $400 which makes this technique valuable for diesel analyses when a large number of tests are required

  2. TCE degradation in groundwater by chelators-assisted Fenton-like reaction of magnetite: Sand columns demonstration.

    Science.gov (United States)

    Jia, Daqing; Sun, Sheng-Peng; Wu, Zhangxiong; Wang, Na; Jin, Yaoyao; Dong, Weiyang; Chen, Xiao Dong; Ke, Qiang

    2018-03-15

    Trichloroethylene (TCE) degradation in sand columns has been investigated to evaluate the potential of chelates-enhanced Fenton-like reaction with magnetite as iron source for in situ treatment of TCE-contaminated groundwater. The results showed that successful degradation of TCE in sand columns was obtained by nitrilotriacetic acid (NTA)-assisted Fenton-like reaction of magnetite. Addition of ethylenediaminedisuccinic acid (EDDS) resulted in an inhibitory effect on TCE degradation in sand columns. Similar to EDDS, addition of ethylenediaminetetraacetic acid (EDTA) also led to an inhibition of TCE degradation in sand column with small content of magnetite (0.5 w.t.%), but enhanced TCE degradation in sand column with high content of magnetite (7.0 w.t.%). Additionally, the presence of NTA, EDDS and EDTA greatly decreased H 2 O 2 uptake in sand columns due to the competition between chelates and H 2 O 2 for surface sites on magnetite (and sand). Furthermore, the presented results show that magnetite in sand columns remained stable in a long period operation of 230 days without significant loss of performance in terms of TCE degradation and H 2 O 2 uptake. Moreover, it was found that TCE was degraded mainly to formic acid and chloride ion, and the formation of chlorinated organic intermediates was minimal by this process. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Performance of soft clay stabilized with sand columns treated by silica fume

    Directory of Open Access Journals (Sweden)

    Samueel Zeena

    2018-01-01

    Full Text Available In many road construction projects, if weak soil exists, then uncontrollable settlement and critical load carrying capacity are major difficult problems to the safety and serviceability of roads in these areas. Thus ground improvement is essential to achieve the required level of performance. The paper presents results of the tests of four categories. First category was performed on saturated soft bed of clay without any treatment, the second category shed light on the improvement achieved in loading carrying capacity and settlement as a result of reinforcing with conventional sand columns at area replacement ratio = 0.196. The third set investigates the bed reinforced by sand columns stabilized with dry silica fume at different percentages (3, 5 and 7% and the fourth set investigates the behavior of sand columns treated with slurry silica fume at two percentages (10 and 12%. All sand columns models were constructed at (R.D= 60%. Model tests were performed on bed of saturated soil prepared at undrained shear strength between 16-20 kPa for all models. For all cases, the model test was loaded gradually by stress increments up to failure. Stress deformation measurements are recorded and analyzed in terms of bearing improvement ratio and settlement reduction ratio. Optimum results were indicated from soil treated with sand columns stabilized with 7% dry silica fume at medium state reflecting the highest bearing improvement ratio (3.04 and the settlement reduction ratio (0.09 after 7 days curing. While soil treated with sand columns stabilized with 10% slurry silica fume provided higher bearing improvement ratio 3.13 with lower settlement reduction ratio of 0.57 after 7-days curing.

  4. Experimental investigation on high performance RC column with manufactured sand and silica fume

    Science.gov (United States)

    Shanmuga Priya, T.

    2017-11-01

    In recent years, the use High Performance Concrete (HPC) has increased in construction industry. The ingredients of HPC depend on the availability and characteristics of suitable alternative materials. Those alternative materials are silica fume and manufactured sand, a by products from ferro silicon and quarry industries respectively. HPC made with silica fume as partial replacement of cement and manufactured sand as replacement of natural sand is considered as sustainable high performance concrete. In this present study the concrete was designed to get target strength of 60 MPa as per guide lines given by ACI 211- 4R (2008). The laboratory study was carried out experimentally to analyse the axial behavior of reinforced cement HPC column of size 100×100×1000mm and square in cross section. 10% of silica fume was preferred over ordinary portland cement. The natural sand was replaced by 0, 20, 40, 60, 80 and 100% with Manufactured Sand (M-Sand). In this investigation, totally 6 column specimens were cast for mixes M1 to M6 and were tested in 1000kN loading frame at 28 days. From this, Load-Mid height deflection curves were drawn and compared. Maximum ultimate load carrying capacity and the least deflection is obtained for the mix prepared by partial replacement of cement with 10% silica fume & natural sand by 100% M-Sand. The fine, amorphous and pozzalonic nature of silica fume and fine mineral particles in M- Sand increased the stiffness of HPC column. The test results revealed that HPC can be produced by using M-Sand with silica fume.

  5. Treatment of Copper Contaminated Municipal Wastewater by Using UASB Reactor and Sand-Chemically Carbonized Rubber Wood Sawdust Column

    Directory of Open Access Journals (Sweden)

    Swarup Biswas

    2016-01-01

    Full Text Available The performance of a laboratory scale upflow anaerobic sludge blanket (UASB reactor and its posttreatment unit of sand-chemically carbonized rubber wood sawdust (CCRWSD column system for the treatment of a metal contaminated municipal wastewater was investigated. Copper ion contaminated municipal wastewater was introduced to a laboratory scale UASB reactor and the effluent from UASB reactor was then followed by treatment with sand-CCRWSD column system. The laboratory scale UASB reactor and column system were observed for a period of 121 days. After the posttreatment column the average removal of monitoring parameters such as copper ion concentration (91.37%, biochemical oxygen demand (BODT (93.98%, chemical oxygen demand (COD (95.59%, total suspended solid (TSS (95.98%, ammonia (80.68%, nitrite (79.71%, nitrate (71.16%, phosphorous (44.77%, total coliform (TC (99.9%, and fecal coliform (FC (99.9% was measured. The characterization of the chemically carbonized rubber wood sawdust was done by scanning electron microscope (SEM, X-ray fluorescence spectrum (XRF, and Fourier transforms infrared spectroscopy (FTIR. Overall the system was found to be an efficient and economical process for the treatment of copper contaminated municipal wastewater.

  6. Treatment of Copper Contaminated Municipal Wastewater by Using UASB Reactor and Sand-Chemically Carbonized Rubber Wood Sawdust Column.

    Science.gov (United States)

    Biswas, Swarup; Mishra, Umesh

    2016-01-01

    The performance of a laboratory scale upflow anaerobic sludge blanket (UASB) reactor and its posttreatment unit of sand-chemically carbonized rubber wood sawdust (CCRWSD) column system for the treatment of a metal contaminated municipal wastewater was investigated. Copper ion contaminated municipal wastewater was introduced to a laboratory scale UASB reactor and the effluent from UASB reactor was then followed by treatment with sand-CCRWSD column system. The laboratory scale UASB reactor and column system were observed for a period of 121 days. After the posttreatment column the average removal of monitoring parameters such as copper ion concentration (91.37%), biochemical oxygen demand (BODT) (93.98%), chemical oxygen demand (COD) (95.59%), total suspended solid (TSS) (95.98%), ammonia (80.68%), nitrite (79.71%), nitrate (71.16%), phosphorous (44.77%), total coliform (TC) (99.9%), and fecal coliform (FC) (99.9%) was measured. The characterization of the chemically carbonized rubber wood sawdust was done by scanning electron microscope (SEM), X-ray fluorescence spectrum (XRF), and Fourier transforms infrared spectroscopy (FTIR). Overall the system was found to be an efficient and economical process for the treatment of copper contaminated municipal wastewater.

  7. Humic colloid-borne migration of uranium in sand columns

    International Nuclear Information System (INIS)

    Artinger, R.; Rabung, T.; Kim, J.I.; Sachs, S.; Schmeide, K.; Heise, K.H.; Bernhard, G.; Nitsche, H.

    2002-09-01

    Column experiments were carried out to investigate the influence of humic colloids on subsurface uranium migration. The columns were packed with well-characterized aeolian quartz sand and equilibrated with groundwater rich in humic colloids (dissolved organic carbon (DOC): 30 mg dm -3 ). U migration was studied under an Ar/1% CO 2 gas atmosphere as a function of the migration time, which was controlled by the flow velocity or the column length. In addition, the contact time of U with groundwater prior to introduction into a column was varied. U(VI) was found to be the dominant oxidation state in the spiked groundwater. The breakthrough curves indicate that U was transported as a humic colloid-borne species with a velocity up to 5% faster than the mean groundwater flow. The fraction of humic colloid-borne species increases with increasing prior contact time and also with decreasing migration time. The migration behavior was attributed to a kinetically controlled association/dissociation of U onto and from humic colloids and also a subsequent sorption of U onto the sediment surface. The column experiments provide an insight into humic colloid-mediated U migration in subsurface aquifers

  8. Compact electron beam focusing column

    Science.gov (United States)

    Persaud, Arun; Leung, Ka-Ngo; Reijonen, Jani

    2001-12-01

    A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.

  9. Influence of porewater advection on denitrification in carbonate sands: Evidence from repacked sediment column experiments

    DEFF Research Database (Denmark)

    Santos, Isaac R.; Eyre, Bradley D.; Glud, Ronnie N.

    2012-01-01

    Porewater flow enhances mineralization rates in organic-poor permeable sands. Here, a series of sediment column experiments were undertaken to assess the potential effect of advective porewater transport on denitrification in permeable carbonate sands collected from Heron Island (Great Barrier Re...

  10. Evaluation by PIXE external beam-of the leaching efficiency for a thermo stated column for the sand treatment

    International Nuclear Information System (INIS)

    Aspiazu, J.; Vite, J.; Vivero, R.; Mendez, B.

    1995-01-01

    The purpose of this paper was to measure the leaching efficiency for a thermo stated column designed to extract metals in muds originated by foundry process. The results obtained were useful to contemplate different alternatives helping to solve the problem of stocking enormous volumes of polluted sand produced by industries. Samples of residual sands and muds (treated sands) coming from an engine factory and from a thermo stated column respectively, were irradiated using an external beam of 3.55 MeV energy protons. From the quantitative analysis PIXE (Proton Induced X-ray Emission), it was possible to establish the level of pollution in sands due to the foundry processes and to evaluate the leaching efficiency of the output liquid phase from the thermo stated column. For polluted sands, certain cases were observed for which the efficiency was not enough to decrease the level of pollution in, e.g., Cu, Zn, Br and Pb. (Author)

  11. Evaluation by PIXE external beam of the leaching efficiency for a thermo stated column for the sand treatment

    International Nuclear Information System (INIS)

    Aspiazu, J.; Vite, J.; Vivero, R.; Mendez, B.

    1995-01-01

    The purpose of this paper was to measure the leaching efficiency for a thermo stated column designed to extract metals in muds originated by foundry processes. The results obtained were useful to contemplate different alternatives helping to solve the problem of stocking enormous volumes of polluted sand produced by industries. Samples of residual sands and muds (treated sands) coming from an engine factory and from a thermo stated column respectively, were irradiated using an external beam of 3.55 MeV energy protons. From the quantitative analysis PIXE (Proton Induced X-ray Emission), it was possible to establish the level of pollution in sands due to the foundry processes and to evaluate the leaching efficiency of the output liquid phase from the thermo stated column. For polluted sands, certain cases were observed for which the efficiency was not enough to decrease the level of pollution in e.g., Cu, Zn, Br y Pb. (Author)

  12. Adsorption and transport of cadmium and rhodamine WT in pumice sand columns

    International Nuclear Information System (INIS)

    Pang, L.; Close, M.; Greenfield, H.; Stanton, G.

    2004-01-01

    The transport and attenuation of cadmium (Cd) and rhodamine WT (RWT) in a pumice sand aquifer media was investigated using column experiments to study a scenario of point-source contamination. A pore-water velocity of 1.7-1.8 m/day, which is a typical field groundwater velocity in a pumice sand aquifer system, was applied to triplicate columns. A pulse of a solution containing Cd and RWT, together with the conservative tracer tritiated water ( 3 H 2 O) at pH = 7, was introduced into the columns. Experimental results showed that concentration breakthrough curves (BTCs) of 3 H 2 O were symmetrical and fitted well into an equilibrium model. In contrast, BTCs of Cd and RWT were asymmetrical with significant tailings and fitted well with a two-site adsorption/desorption model. The symmetric 3 H 2 O BTCs suggest that physical non-equilibrium was absent in the experimental system, therefore the asymmetrical BTCs of Cd and RWT were attributed to chemical non-equilibrium. Modelling results showed that, in comparison with 3 H 2 O, Cd was apparently retarded by 101-108 times in pumice sand aquifer media (apparent adsorption coefficient 7.33-9.24 ml/g) and underwent a mass loss of 20-30% that was probably because of precipitation of CdCO 3 . As CdCO 3 is extremely insoluble, Cd precipitation would be irreversible and therefore it would not contribute to the tailing of the Cd BTCs. The experimental results suggest that the adsorption and desorption of Cd in pumice sand aquifer media in hydrodynamic conditions was a kinetic process. Cd desorption rates were two orders-of-magnitude slower than its adsorption rates. This resulted in a prolonged mean residence time for Cd in pumice sand aquifer media, which was 10-12 days in the 18-cm-long columns under a flow velocity of 1.7-1.8 m/day. Since the mean residence time is only indicative for the arrival of the central of mass in a contaminant BTC, the time required for the total disappearance of Cd will be much longer than the mean

  13. Diffusive transport of radon in a homogeneous column of dry sand

    NARCIS (Netherlands)

    van der Spoel, W.H.; van der Graaf, E.R.; de Meijer, R.J.

    To validate a model for radon transport in soil, measurements of diffusive radon transport under well-defined and controlled conditions have been made in a homogeneous column of dry sand with an air-filled volume on top. This volume simulates a crawl space. The measurements concern time-dependent

  14. Study of penetration behavior of PCB-DNAPL in a sand layer by a column experiment.

    Science.gov (United States)

    Okuda, Nobuyasu; Shimizu, Takaaki; Muratani, Masaru; Terada, Akihiko; Hosomi, Masaaki

    2014-11-01

    To better understand the infiltration performances of high concentration PCB oils (KC-300 and KC-1000 polychlorinated biphenyl (PCB) mixtures), representative dense non-aqueous phase liquid (DNAPL), under both saturated and unsaturated conditions, we conducted experiments on a sand column filled with Toyoura Standard Sand. When PCB oil with the volume comparable to the total porosity in the column was supplied, the residual PCB concentrations under PCB-water conditions were 4.9×10(4)mgkg(-1) in KC-300 and 3.9×10(4)mgkg(-1) in KC-1000. Under PCB-air conditions, residual PCB concentrations were 6.0×10(4)mgkg(-1) and 2.4×10(5)mgkg(-1) in the upper and lower parts for KC-300 and 3.6×10(4)mgkg(-1) and 1.5×10(5)mgkg(-1) in those for KC-1000, respectively, while the rest of the PCBs were infiltrated. On the other hand, when a small amount of PCB oil with the volume far smaller than the total porosity in the column was supplied, the original PCBs were not transported via water permeation. However, lower-chlorinated PCB congeners-e.g., di- or tri-chlorinated biphenyls-preferentially dissolved and were infiltrated from the bottom of the column. These propensities on PCB oil infiltration can be explained in conjunction with the degree of PCB saturation in the sand column. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Continuous adsorption of Pb(II) and methylene blue by engineered graphite oxide coated sand in fixed-bed column

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Ji-Lai, E-mail: jilaigong@gmail.com [College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082 (China); Zhang, Yong-Liang; Jiang, Yan [College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082 (China); Zeng, Guang-Ming, E-mail: zgming@hnu.edu.cn [College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082 (China); Cui, Zhi-Hui; Liu, Ke; Deng, Can-Hui; Niu, Qiu-Ya; Deng, Jiu-Hua [College of Environmental Science and Engineering, Key Laboratory of Environmental Biology and Pollution Control, Ministry of Education, Hunan University, Changsha 410082 (China); Huan, Shuang-Yan [State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

    2015-03-01

    Highlights: • GO-sand was prepared by coating GO on the surface of sand. • Pb(II) and MB were efficiently removed by GO-sand filter in column. • The removal of MB was enhanced with the presence of Pb(II). • GO-sand is low-cost and convenient for its application as packed bed filter. - Abstract: The mixture of several effluents, caused by the improper handling and management of effluents, generated multi-component wastewater containing both metals and dyes, leading to the complicated treatment process. In this study, a continuous adsorption of Pb(II) and methylene blue (MB) has been studied in single and binary solutions by using graphite oxide coated sand (GO-sand) as an adsorbent in a fixed-bed column. GO-sand was analyzed by X-ray photoelectron spectroscopy before and after analyte adsorption. Compared with sand filter, adsorption quantity and capacity for Pb(II) and MB by GO-sand filter were greatly increased. In Pb(II) and MB single solutions, the experimental parameters were investigated in detail including initial concentration, flow rate, bed depth and pH. Exhaustion time decreased with increasing initial concentration and flow rate, and increased with increasing bed depth and pH. In the Pb(II)-MB binary solution, exhaustion time significantly decreased for Pb(II) adsorption, but increased for MB adsorption. The reason was explained that the more favorable adsorption for MB onto the surface of GO-sand than that for Pb(II), which was derived from π–π interaction between MB and GO on sand surface in packed filter. The Yoon–Nelson model was applied at different concentration of Pb(II) and MB to predict the breakthrough curves. The experimental data were well fit with the model indicating that it was suitable for this column design.

  16. Numerical Evaluation on the Different Shapes of Gravelly Sand Columns to Increase the Loading Capacity of Soft Clay

    Directory of Open Access Journals (Sweden)

    Meghzili Sif Allah

    2017-01-01

    Full Text Available Improvement on soft clay by the installation of stone column is one of the most popular methods followed worldwide. Different analytical and numerical solutions have already been developed for understanding the load transfer mechanism of soft soil reinforced with stone column. This study investigated a bearing capacity of the gravelly sand column, installed in soft clay bed at 15kpa of undrained shear strength. The column variable of length and diameter ratio at 7, 8 and 9 were evaluated. On top of that, the combination of two diameters in single column was tested and the uniform diameter was used as a control. In the numerical analysis, Mohrcoulomb model was adopted in the idealization of the behaviour of the gravelly sand column and soft clay materials. The results revealed that the optimum design that gave the highest loading capacity of the combination 11=12 of column diameter was the length and diameter ratio of 8.

  17. Study of Black Sand Particles from Sand Dunes in Badr, Saudi Arabia Using Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Haider Abbas Khwaja

    2015-08-01

    Full Text Available Particulate air pollution is a health concern. This study determines the microscopic make-up of different varieties of sand particles collected at a sand dune site in Badr, Saudi Arabia in 2012. Three categories of sand were studied: black sand, white sand, and volcanic sand. The study used multiple high resolution electron microscopies to study the morphologies, emission source types, size, and elemental composition of the particles, and to evaluate the presence of surface “coatings or contaminants” deposited or transported by the black sand particles. White sand was comprised of natural coarse particles linked to wind-blown releases from crustal surfaces, weathering of igneous/metamorphic rock sources, and volcanic activities. Black sand particles exhibited different morphologies and microstructures (surface roughness compared with the white sand and volcanic sand. Morphological Scanning Electron Microscopy (SEM and Laser Scanning Microscopy (LSM analyses revealed that the black sand contained fine and ultrafine particles (50 to 500 nm ranges and was strongly magnetic, indicating the mineral magnetite or elemental iron. Aqueous extracts of black sands were acidic (pH = 5.0. Fe, C, O, Ti, Si, V, and S dominated the composition of black sand. Results suggest that carbon and other contaminant fine particles were produced by fossil-fuel combustion and industrial emissions in heavily industrialized areas of Haifa and Yanbu, and transported as cloud condensation nuclei to Douf Mountain. The suite of techniques used in this study has yielded an in-depth characterization of sand particles. Such information will be needed in future environmental, toxicological, epidemiological, and source apportionment studies.

  18. A novel bench-scale column assay to investigate site-specific nitrification biokinetics in biological rapid sand filters

    DEFF Research Database (Denmark)

    Tatari, Karolina; Smets, Barth F.; Albrechtsen, Hans-Jørgen

    2013-01-01

    A bench-scale assay was developed to obtain site-specific nitrification biokinetic information from biological rapid sand filters employed in groundwater treatment. The experimental set-up uses granular material subsampled from a full-scale filter, packed in a column, and operated with controlled...

  19. Microbially induced carbonate precipitation (MICP) by denitrification as ground improvement method - Process control in sand column experiments

    Science.gov (United States)

    Pham, Vinh; van Paassen, Leon; Nakano, Akiko; Kanayama, Motohei; Heimovaara, Timo

    2013-04-01

    Calcite precipitation induced by microbes has been proven to be efficient in stabilizing granular soils, especially with urea hydrolysis, as it has been successfully demonstrated in a pilot application 2010. However, as a byproduct highly concentrated ammonium chloride (NH4Cl) solution is produced, which has to be removed and disposed and forms a significant disadvantage of the technique that makes an alternative process like denitrification preferred. The proof of principle of microbially induced calcite precipitation (MICP) by denitrification has been demonstrated by Van Paassen et al (2010) who suggested that instead of producing waste as a byproduct, different pre-treated waste streams could be used as substrates for in situ growth of denitrifying bacteria and simultaneous cementation without producing waste to be removed. In this study sand column experiments are performed in which calcium carbonate was successfully precipitated by indigenous denitrifying micro-organisms, which were supplied weekly with a pulse of a substrate solution containing calcium acetate and calcium nitrate. Besides the production of calcite and the growth of bacteria in biofilms, the reduction of nitrate resulted in the production of (nitrogen) gas. It was observed that this gas partly fills up the pore space and consequently contributed to a reduction of the permeability of the treated sand. The presence of gas in the pore space affected the flow of the injected substrates and influenced to the distribution of calcium carbonate. The effect of the mean particle size (D50) on the flow and transport of solutes and gas in the porous media has been evaluated by treating several columns with varying grain size distribution and comparing the change in permeability after each incubation period and analyzing the distribution of the gas throughout the columns using X-ray computed tomography (CT) scanning. The present results show that there is a considerable decrease of permeability - a

  20. Atomic column resolved electron energy-loss spectroscopy

    International Nuclear Information System (INIS)

    Duscher, G.; Pennycook, S.J.; Browning, N.D.

    1998-01-01

    Spatially resolved electron energy-loss spectroscopy (EELS) is rapidly developing into a unique and powerful tool to characterize internal interfaces. Because atomic column resolved Z-contrast imaging can be performed simultaneously with EELS in the scanning transmission electron microscope, this combination allows the atomic structure to be correlated with the electronic structure, and thus the local properties of interfaces or defects can be determined directly. However, the ability to characterize interfaces and defects at that level requires not only high spatial resolution but also the exact knowledge of the beam location, from where the spectrum is obtained. Here we discuss several examples progressing from cases where the limitation in spatial resolution is given by the microscopes or the nature of the sample, to one example of impurity atoms at a grain boundary, which show intensity and fine structure changes from atomic column to atomic column. Such data can be interpreted as changes in valence of the impurity, depending on its exact site in the boundary plane. Analysis ofthis nature is a valuable first step in understanding the microscopic structural, optical and electronic properties of materials. (orig.)

  1. Effects of water content on reactive transport of Sr in Chernobyl sand columns

    International Nuclear Information System (INIS)

    Szenknect, S.; Dewiere, L.; Ardois, C.; Gaudet, J.P.

    2005-01-01

    Full text of publication follows: While transport of non-reactive solutes has been studied extensively in unsaturated porous media, much less is known about the factors that control the transport of sorbing solutes in unsaturated conditions. Three laboratory techniques were used to analyze the transport of Sr in the aeolian sand from Chernobyl Pilot Site [1] in both saturated and unsaturated flow conditions. Batch experiments were performed to study the chemical equilibrium state of the soil/solution system. Stirred flow-through reactor (SFTR) experiments were performed to study the kinetics and reversibility of sorption reactions at the surface of solid particles. Column experiments were also performed in saturated and unsaturated steady flow conditions. Experimental data pointed out a non-linear, instantaneous and reversible sorption process of Sr. A suitable cation-exchange model was used to describe the solute/soil reaction. The former model was coupled with transport models to describe behavior of Sr in saturated [2] and unsaturated flow conditions. Transport properties of sand packed columns have been determined with an inert tracer (HTO). BTCs obtained under saturated conditions exhibit a small amount of dispersion compared to those obtained under unsaturated conditions. Classical advection-dispersion model described successfully saturated tritium breakthrough curves (BTCs), whereas a mobile-immobile model (MIM) was required to described asymmetrical unsaturated BTCs. The MIM assumes that the porous medium contains a mobile water phase in which convective-dispersive transport occurs, and a immobile water phase with which solutes can exchange with a first order kinetic. In our experiments, transport by advection in the mobile phase is the predominant process whatever the flow conditions and mass transfer rate between the mobile and immobile regions is the predominant process for broadening the BTCs. Since dispersion is blurred by mass transfer resistance, the

  2. Bioaugmentation of flow-through sand filters

    DEFF Research Database (Denmark)

    Samuelsen, Elin Djurhuus

    for degradation performances in flow-through sand columns, with the aim of identifying a suitable inoculant strain for future environmental applications. Another aim was to identify a suitable genetic marker to monitor phenoxy acid degradation in strain Sphingobium sp. PM2. We were not able to link motility...... and biofilm formation to the strains´ ability to adhere to sand. Nevertheless, a correlation was found between cell surface hydrophobicity and adhesion and overall degradation performances in flow-through sand columns. We identified S phingobium sp. PM2 as a promising inoculant strain, displaying efficient...... MCPA degradation for prolonged periods in flow-through sand columns. In an expression study of catabolic genes with putative roles in phenoxy acid degradation, we observed a marked upregulation of catabolic genes cadA and tfdC upon exposure to MCPA, 2,4-D, dichlorprop and mecoprop in strain PM2, which...

  3. Permanent magnet finger-size scanning electron microscope columns

    Energy Technology Data Exchange (ETDEWEB)

    Nelliyan, K., E-mail: elenk@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Khursheed, A. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)

    2011-07-21

    This paper presents permanent magnet scanning electron microscope (SEM) designs for both tungsten and field emission guns. Each column makes use of permanent magnet technology and operates at a fixed primary beam voltage. A prototype column operating at a beam voltage of 15 kV was made and tested inside the specimen chamber of a conventional SEM. A small electrostatic stigmator unit and dedicated scanning coils were integrated into the column. The scan coils were wound directly around the objective lens iron core in order to reduce its size. Preliminary experimental images of a test grid specimen were obtained through the prototype finger-size column, demonstrating that it is in principle feasible.

  4. Permanent magnet finger-size scanning electron microscope columns

    International Nuclear Information System (INIS)

    Nelliyan, K.; Khursheed, A.

    2011-01-01

    This paper presents permanent magnet scanning electron microscope (SEM) designs for both tungsten and field emission guns. Each column makes use of permanent magnet technology and operates at a fixed primary beam voltage. A prototype column operating at a beam voltage of 15 kV was made and tested inside the specimen chamber of a conventional SEM. A small electrostatic stigmator unit and dedicated scanning coils were integrated into the column. The scan coils were wound directly around the objective lens iron core in order to reduce its size. Preliminary experimental images of a test grid specimen were obtained through the prototype finger-size column, demonstrating that it is in principle feasible.

  5. Sand filter clogging by septic tank effluent.

    Science.gov (United States)

    Spychała, M; Błazejewski, R

    2003-01-01

    The aim of this study was to characterise conditions and factors affecting fine sand clogging by septic tank effluent on the basis of physical modelling. The physical model consisted of 12 sand columns dosed with sewage from one household (5 persons), preliminary treated in a septic tank. Hydraulic loadings of the sand filters were equal to 82 mm/d. The mean discharge from sand columns, measured as the effluent volume collected during 10 minutes, decreased significantly over the experiment period from 34 cm3/min in August 2000 to 20 cm3/min in August 2001 at the same temperature of about 20 degrees C. First the columns clogged almost completely after 480 days in December 2001, however six columns had remained unclogged till the end of the experiment (March 2002). The temperature had a significant impact on hydraulic conductivity. A vertical distribution of accumulated mass and biomass was investigated in partly clogged sand. Microscopic survey of the clogging layer showed a presence of live micro-organisms, residuals of dead micro-organisms, particularly pieces of small animal armour and many fibres. These particles accelerated the accumulation of solids in the upper clogging layer. The study indicated that temperature impact on the filter hydraulic conductivity was more significant for biological activity, than for sewage viscosity.

  6. Hydrogen peroxide stabilization in one-dimensional flow columns

    Science.gov (United States)

    Schmidt, Jeremy T.; Ahmad, Mushtaque; Teel, Amy L.; Watts, Richard J.

    2011-09-01

    Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H 2O 2 propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO.

  7. Zirconium oxide-coated sand based batch and column adsorptive removal of arsenic from water: Isotherm, kinetic and thermodynamic studies

    Directory of Open Access Journals (Sweden)

    Saif Ali Chaudhry

    2017-06-01

    Full Text Available This paper reports zirconium oxide-coated sand preparation, characterization by SEM, EDX, XRD, FT-IR and thermoanalytical techniques, and use as an adsorbent for the removal of most toxic form of arsenic, As(III, from aqueous solution in both batch and column methods. Batch experimental parameters such as contact time, concentration, dose of adsorbent, pH of As(III solution and temperature were optimized. The adsorption data was fitted to Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms at 303, 308 and 313 K. The maximum Langmuir monolayer adsorption capacity was found to be 136.98 μg/g at 313 K. Values of ΔH°, ΔG° and ΔS° were found to be −12.90, −8.74 to –8.28 and 0.014 kJ/mol, suggesting exothermic and spontaneous adsorption process with slight increase in entropy. The adsorption process followed pseudo-second order kinetics and was controlled by film diffusion step. The column studies showed that when flow rate was increased from 3.0 to 5.0 mL/min, the arsenic adsorption capacity of ZrOCS increased from 33.104 to 42.231 μg/g and breakthrough, and exhaustion times got reduced reduced. The results indicated that zirconium oxide-coated sand (ZrOCS is an excellent adsorbent for the removal of As(III from water.

  8. Finite length thermal equilibria of a pure electron plasma column

    International Nuclear Information System (INIS)

    Prasad, S.A.; O'Neil, T.M.

    1979-01-01

    The electrons of a pure electron plasma may be in thermal equilibrium with each other and still be confined by static magnetic and electric fields. Since the electrons make a significant contribution to the electric field, only certain density profiles are consistent with Poisson's equation. The class of such distributions for a finite length cylindrical column is investigated. In the limit where the Debye length is small compared with the dimensions of the column, the density is essentially constant out to some surface of revolution and then falls off abruptly. The falloff in density is a universal function when measured along the local normal to the surface of revolution and scaled in terms of the Debye length. The solution for the shape of the surface of revolution is simplified by passage to the limit of zero Debye length

  9. The migration of colloidal particles through glacial sand

    International Nuclear Information System (INIS)

    Harrison, I.; Higgo, J.J.W.; Leader, R.; Noy, D.; Smith, B.; Wealthall, G.; Williams, G.M.

    1991-02-01

    Significant concentrations of colloids exist in groundwater and radionuclides may be associated with this colloidal material. This must be taken into consideration in any safety case for a radionuclide waste repository. This report describes column experiments with monodisperse latex beads. A selection of beads with diameters ranging from 0.055 μm to 0.6 μm, some plain and some with carboxyl groups attached, were passed through columns of glacial sand. The breakthrough curves and profiles on the sand columns were studied and will be used to develop and validate colloid migration models. The mobility depended on both size and charge, and the beads appeared to move ahead of a 36Cl tracer until they were trapped. After trapping movement was slow with plain beads appearing to be slightly more mobile than carboxylated beads. The beads were shown to sorb strongly on the fine clay particles in the sand and there was evidence to suggest that they moved with the fines rather than independently. (author)

  10. Design and implementation of a micron-sized electron column fabricated by focused ion beam milling

    Energy Technology Data Exchange (ETDEWEB)

    Wicki, Flavio, E-mail: flavio.wicki@physik.uzh.ch; Longchamp, Jean-Nicolas; Escher, Conrad; Fink, Hans-Werner

    2016-01-15

    We have designed, fabricated and tested a micron-sized electron column with an overall length of about 700 microns comprising two electron lenses; a micro-lens with a minimal bore of 1 micron followed by a second lens with a bore of up to 50 microns in diameter to shape a coherent low-energy electron wave front. The design criteria follow the notion of scaling down source size, lens-dimensions and kinetic electron energy for minimizing spherical aberrations to ensure a parallel coherent electron wave front. All lens apertures have been milled employing a focused ion beam and could thus be precisely aligned within a tolerance of about 300 nm from the optical axis. Experimentally, the final column shapes a quasi-planar wave front with a minimal full divergence angle of 4 mrad and electron energies as low as 100 eV. - Highlights: • Electron optics • Scaling laws • Low-energy electrons • Coherent electron beams • Micron-sized electron column.

  11. Transport and Deposition of Suspended Soil-Colloids in Saturated Sand Columns

    DEFF Research Database (Denmark)

    Sharma, Anu; Kawamoto, Ken; Møldrup, Per

    2011-01-01

    Understanding colloid mobilization, transport and deposition in the subsurface is a prerequisite for predicting colloid‐facilitated transport of strongly adsorbing contaminants and further developing remedial activities. This study investigated the transport behavior of soil‐colloids extracted from...... caused tailing of colloid BTCs with higher reversible entrapment and release of colloids than high flow velocity. The finer Toyoura sand retained more colloids than the coarser Narita sand at low pH conditions. The deposition profile and particle size distribution of colloids in the Toyoura sand clearly...

  12. Complex conductivity response to silver nanoparticles in partially saturated sand columns

    Science.gov (United States)

    Abdel Aal, Gamal; Atekwana, Estella A.; Werkema, D. Dale

    2017-02-01

    The increase in the use of nanoscale materials in consumer products has resulted in a growing concern of their potential hazard to ecosystems and public health from their accidental or intentional introduction to the environment. Key environmental, health, and safety research needs include knowledge and methods for their detection, characterization, fate, and transport. Specifically, techniques available for the direct detection and quantification of their fate and transport in the environment are limited. Their small size, high surface area to volume ratio, interfacial, and electrical properties make metallic nanoparticles, such as silver nanoparticles, good targets for detection using electrical geophysical techniques. Here we measured the complex conductivity response to silver nanoparticles in sand columns under varying moisture conditions (0-30%), nanoparticle concentrations (0-10 mg/g), lithology (presence of clay), pore water salinity (0.0275 and 0.1000 S/m), and particle size (35, 90-210 and 1500-2500 nm). Based on the Cole-Cole relaxation models we obtained the chargeability and the time constant. We demonstrate that complex conductivity can detect silver nanoparticles in porous media with the response enhanced by higher concentrations of silver nanoparticles, moisture content, ionic strength, clay content and particle diameter. Quantification of the volumetric silver nanoparticles content in the porous media can also be obtained from complex conductivity parameters based on the strong power law relationships.

  13. Enhanced Column Filtration for Arsenic Removal from Water: Polymer-Templated Iron Oxide Nanoparticles Immobilized on Sand via Layer-by-Layer Deposition

    Science.gov (United States)

    Cheng, Calvin Chia-Hung

    Arsenic is ubiquitous in water sources around the world and is highly toxic. While precipitation and membrane filtration techniques are successfully implemented in developed cities, they are unsuitable for rural and low-resource settings lacking centralized facilities. This thesis presents the use of ultra-small iron oxide (Fe2O3) nanoparticles functionalized on sand granules for use as a house-hold scale adsorption filter. Water-stable alpha-Fe2O3 (hematite) nanoparticles (arsenic adsorption, with 147 +/- 2 mg As(III) per g Fe2O3 and 91 +/- 10 mg As(V) per g Fe2O3. The platform was also used to synthesize iron-based composites, including magnetite (Fe 3O4) and Fe-Cu oxide nanoparticles. For use as a column filter, Fe2O3-PAA nanoparticles were functionalized on sand granules using a layer-by-layer deposition method, with the nanoparticles embedded in the negative layer. The removal of As(III) by the Fe2O 3-PAA functionalized column was described by reversible 1st order kinetics where the forward and reverse rate constants were 0.31 hr -1 and 0.097 hr-1, respectively. Implemented as a passive water filter with 30 x 30 x 50 cm3 dimensions, the filter has an expected lifetime in the order of many years. By controlling the flow rate of the column depending on contamination levels, the filter effectively removes arsenic down to the safety limit of 0.01 mg/L. In a parallel project, the layer-by-layer deposition of Poly(diallydimethyl ammonium chloride) (PDDA) and poly(sodium 5-styrenesulfonate) (PSS) was exploited for a highly practical synthesis of discrete gradient surfaces. By independently controlling the concentration of NaCl in PDDA and PSS deposition solutions, a 2-dimensional matrix of surfaces was created in 96-well microtiter plates. Distinct non-monotonic dye adsorption patterns on the gradient surfaces was observed. Practical knowledge from this project was also used to enhance the nanoparticle surface functionalization described above. In all, a practical

  14. HF heating of a plasma column at frequencies below the electron cyclotron frequency

    International Nuclear Information System (INIS)

    Datlov, J.; Kopecky, V.; Musil, J.; Zacek, F.; Novik, K.

    1978-02-01

    The dispersion of waves, excited by the helical structure in a plasma column and the heating of a tail of the electron distribution function is studied at frequencies below the electron plasma frequency and the electron cyclotron frequency. (author)

  15. Pathogen removal using saturated sand colums supplemented with hydrochar

    NARCIS (Netherlands)

    Chung, J.W.

    2015-01-01

    This PhD study has evaluated hydrochars derived from biowastes as adsorbents for pathogen removal in water treatment. Pathogen removal experiments were conducted by carrying out breakthrough analysis using a simple sand filtration set-up. Glass columns packed by 10 cm sand bed supplemented with

  16. Removal of dissolved heavy metals from pre-settled stormwater runoff by iron-oxide coated sand (IOCS)

    DEFF Research Database (Denmark)

    Møller, J.; Ledin, Anna; Mikkelsen, Peter Steen

    2002-01-01

    (Pb=20, Cu=40, Zn=110, and Cr=15 ppb). Column experiments were conducted to test the influence of the infiltration rate (1 or 3 m/h) and the type of iron(hydr)oxide mineral (amorphous ferrihydrite and goethite coated sand). The results show that at least 90% of lead, copper and zinc can be removed......Sorption to iron-oxide coated sand (IOCS) is a promosing technology for removal of the dissolved heavy metal fraction in stormwater runoff. The development of a new technology is necessary since studies of stormwater runoff from traffic areas indicate that an oil separator and detention pond may...... by IOCS after 480 pore volumes. Control columns with uncoated filter sand show that lead, copper and zinc were removed with >95%, 35% and 5%, respectively. The removal of the negative metaloxy-ion, CrO4-3 was insignificant in both IOCS and sand columns at pH=7.7. Destruction of the columns after...

  17. Fluoride retardation from quartz sand-packed column tests

    Directory of Open Access Journals (Sweden)

    Eduardo Usunoff

    2009-06-01

    Full Text Available Inasmuch as both low and high concentrations of F- in groundwater have different detrimental effects on human health (increased dental caries, and mottled enamel or even severe structural bone deformations, respectively, many efforts have focused on the movement of such anion in aqueous systems. It is so because water drinking is the main intake of F- by humans. This paper presents the results of seven dynamic experiments in which solutions of varying [F-], pH, and flow velocities circulated through columns packed with clean quartz sand. The breakthrough data were analyzed by means of a computer code adapted to the estimation of equilibrium and non-equilibrium solute transport parameters from miscible displacement experiments in a steady-state, uniform flow field using a pulse-type or continuous source. It was found that larger retardation factors (R are associated with low pH, low [F-] in the feed solutions, and larger flow velocities. Such results appear to be related to the form of the F species, the rather weak bond between the adsorbate and the quartz sand, and stronger anion repulsion at low pore velocities. The estimated values for R vary between 1,22 and 1,50, whereas the distribution coefficients were in the range of 0,1 to 0,05 L kg-1. It should be said that the breakthrough curves display hysteresis, leading to a desorption behavior that proceeds faster than the adsorption process.Puesto que tanto valores bajos como altos de F- en las aguas subterráneas tienen efectos adversos en la salud de los humanos (mayor cantidad de caries, y manchas del esmalte dental e incluso deformaciones óseas, respectivamente, han sido muchos los esfuerzos destinados a dilucidar el movimiento de especies fluoradas en ambientes acuosos. Ello es así porque el consumo de agua por parte de seres humanos representa la mayor fuente de ingreso de F-. Este trabajo presenta los resultados de siete experimentos dinámicos en los que soluciones de diferentes [F

  18. Sedimentological and Scanning Electron Miscroscopic Descriptions of Afowo Oil Sand Deposits, South Western Nigeria

    Directory of Open Access Journals (Sweden)

    Akinmosin A

    2017-12-01

    Full Text Available Sedimentological and scanning electron microscopic analyses of some shallow reservoir tar sand samples in parts of Southwestern Nigeria were carried out with the aim of characterizing the reservoir properties in relation to bitumen saturation and recovery efficiency. The production of impregnated tar from the sands requires the reservoir to be of good quality. A total of thirty samples were collected at different localities within the tar sand belt (ten out of these samples were selected for various reservoir quality analyses based on their textural homogeneity. The result of particle size distribution study showed that bulk of the sands is medium – coarse grained and moderately sorted. The grain morphologies are of low to high sphericity with shapes generally sub-angular to sub-rounded, implying that the sands have undergone a fairly long transportation history with depositional energy having a moderate to high velocity. The quartz content was made up of about 96% of the total mineralogical components; the sediments of the Afowo Formation can be described to be mineralogically and texturally stable. The result of the scanning electron microscopy (SEM analysis revealed that the oil sands contained minerals which had been precipitated and occurred as pore filling cement; these minerals include sheet kaolinite, block kaolinite, vermiform kaolinite, pyrite crystals and quartz. The SEM images also showed micro-pores ranging from 0.057µm to 0.446µm and fractures. The study showed that the clay minerals contained in the Afowo reservoir rocks were mainly kaolinite. Kaoline unlike some other clays (e.g Montimorillonite does not swell with water, hence it is not expected to have any negative effects on the reservoir quality, especially during enhanced oil recovery operations.

  19. On mixed electron-photon radiation therapy optimization using the column generation approach.

    Science.gov (United States)

    Renaud, Marc-André; Serban, Monica; Seuntjens, Jan

    2017-08-01

    Despite considerable increase in the number of degrees of freedom handled by recent radiotherapy optimisation algorithms, treatments are still typically delivered using a single modality. Column generation is an iterative method for solving large optimisation problems. It is well suited for mixed-modality (e.g., photon-electron) optimisation as the aperture shaping and modality selection problem can be solved rapidly, and the performance of the algorithm scales favourably with increasing degrees of freedom. We demonstrate that the column generation method applied to mixed photon-electron planning can efficiently generate treatment plans and investigate its behaviour under different aperture addition schemes. Column generation was applied to the problem of mixed-modality treatment planning for a chest wall case and a leg sarcoma case. 6 MV beamlets (100 cm SAD) were generated for the photon components along with 5 energies for electron beamlets (6, 9, 12, 16 and 20 MeV), simulated as shortened-SAD (80 cm) beams collimated with a photon MLC. For the chest wall case, IMRT-only, modulated electron radiation therapy (MERT)-only, and mixed electron-photon (MBRT) treatment plans were created using the same planning criteria. For the sarcoma case, MBRT and MERT plans were created to study the behaviour of the algorithm under two different sets of planning criteria designed to favour specific modalities. Finally, the efficiency and plan quality of four different aperture addition schemes was analysed by creating chest wall MBRT treatment plans which incorporate more than a single aperture per iteration of the column generation loop based on a heuristic aperture ranking scheme. MBRT plans produced superior target coverage and homogeneity relative to IMRT and MERT plans created using the same optimisation criteria, all the while preserving the normal tissue-sparing advantages of electron therapy. Adjusting the planning criteria to favour a specific modality in the sarcoma

  20. 振冲碎石桩加固高层建筑粉砂土地基实例分析%Case Study on Improving Silty Sand Foundation of Tall Building by Vibro-replacement Stone Column

    Institute of Scientific and Technical Information of China (English)

    谢新宇; 应宏伟; 夏建中

    2001-01-01

    In this paper, the case studies of two tall buildings built on silty sand improved by vibro-replacement stone column in Hangzhou are reported. The design and computation method for vibro-replacement stone column composite foundation are introduced. Based on field testing results,the construction techniques of vibro-replacement stone column and the appraisement of improvement effect are discussed. It is the first time that the vibro-replacement stone column method has been successfully applied to improve silty sand foundation of tall building in Hangzhou.%本文介绍杭州两座高层建筑物采用振冲碎石桩加固粉砂土地基的工程实例。结合有关现场测试成果,探讨了高层建筑振冲碎石桩地基设计计算、振冲碎石桩施工控制和加固效果评价等有关问题。为振冲碎石桩在同类地基中的推广应用提供一些成功经验。

  1. Study of Slow Sand Filtration in Removing Total Coliforms and E.Coli

    Directory of Open Access Journals (Sweden)

    Ekha Yogafanny

    2015-08-01

    Full Text Available This study was aimed to evaluate the performance of SSF in removing bacteria (Total Coliforms and E. Coli in regard to grain size distribution and grain shape intermittently. Two methodological approaches used in this reasearch were literature review and laboratory work. Bacteria removal was analyzed considering two different filter media (Rhine sand-spherical shape and Lava sand-angular shape with three different grain size distributions. The best performance was attained by filter column F4 which consisted of Lava sand and had the configuration C2 (d10 = 0.07 mm; Cu = 4.2. This filter column achieved 4.7log-units removal of Total Coliforms and 5.0log-units removal of E. coli. The results show that a smaller grain size and an angular shape of sand grain lead to an increase in bacteria removal.

  2. Influence of transient flow on the mobility of strontium in unsaturated sand column

    International Nuclear Information System (INIS)

    Mazet, P.

    2008-10-01

    The reactive transport of 85 Sr was studied on laboratory columns, focusing on the influence of transient unsaturated flow (cycles of infiltration and redistribution) associated with controlled geochemistry (constant concentrations of major elements and stable strontium in water). An original experimental tool (gamma attenuation system) allows us to follow at the same time the variations of humidity of the soil and the migration of radionuclide, in a non-destroying and definite way. First stage of this study concerned the implementation of the experimental tool to measure transient hydraulic events within the columns of sand. Several experiments of transport of 85 Sr were then performed with different water condition (saturated, unsaturated, permanent and transient flow). Experimental results were simulated using the computer codes HYDRUS-1D (phenomenological approach with partition coefficient K d ) and HYTEC (mechanistic geochemical/transport approach). Confrontation between experience and modelling shows that, for our operating conditions, transfer of 85 Sr can be predicted with an 'operational' approach using: 1) simplified geochemical model with partition coefficient K d concerning interactive reaction with the soil (K d value determined independently on saturated column, with the same water geochemistry), 2) permanent saturated (or unsaturated) flow, taking into account the cumulated infiltrated water during unsaturated transient hydraulic events concerning hydrodynamic. Generalization of these results (area of validity) suggests that the 'cumulated infiltrated water + K d ' approach can be use, for controlled water geochemistry, when the numerical value of K d is fairly strong (K d ≥≥1), and that it is insensitive to the value of the water content. Moreover, the presence of immobile water (∼10%) recorded with tritium transport, is undetectable with strontium. Explanation of this result is allocated to the different characteristic time residence

  3. Modeling a Miniaturized Scanning Electron Microscope Focusing Column - Lessons Learned in Electron Optics Simulation

    Science.gov (United States)

    Loyd, Jody; Gregory, Don; Gaskin, Jessica

    2016-01-01

    This presentation discusses work done to assess the design of a focusing column in a miniaturized Scanning Electron Microscope (SEM) developed at the NASA Marshall Space Flight Center (MSFC) for use in-situ on the Moon-in particular for mineralogical analysis. The MSFC beam column design uses purely electrostatic fields for focusing, because of the severe constraints on mass and electrical power consumption imposed by the goals of lunar exploration and of spaceflight in general. The resolution of an SEM ultimately depends on the size of the focused spot of the scanning beam probe, for which the stated goal here is a diameter of 10 nanometers. Optical aberrations are the main challenge to this performance goal, because they blur the ideal geometrical optical image of the electron source, effectively widening the ideal spot size of the beam probe. In the present work the optical aberrations of the mini SEM focusing column were assessed using direct tracing of non-paraxial rays, as opposed to mathematical estimates of aberrations based on paraxial ray-traces. The geometrical ray-tracing employed here is completely analogous to ray-tracing as conventionally understood in the realm of photon optics, with the major difference being that in electron optics the lens is simply a smoothly varying electric field in vacuum, formed by precisely machined electrodes. Ray-tracing in this context, therefore, relies upon a model of the electrostatic field inside the focusing column to provide the mathematical description of the "lens" being traced. This work relied fundamentally on the boundary element method (BEM) for this electric field model. In carrying out this research the authors discovered that higher accuracy in the field model was essential if aberrations were to be reliably assessed using direct ray-tracing. This led to some work in testing alternative techniques for modeling the electrostatic field. Ultimately, the necessary accuracy was attained using a BEM

  4. Transport of microbial tracers in clean and organically contaminated silica sand in laboratory columns compared with their transport in the field

    International Nuclear Information System (INIS)

    Weaver, Louise; Sinton, Lester W.; Pang, Liping; Dann, Rod; Close, Murray

    2013-01-01

    Waste disposal on land and the consequent transport of bacterial and viral pathogens in soils and aquifers are of major concern worldwide. Pathogen transport can be enhanced in the presence of organic matter due to occupation of attachment sites in the aquifer materials thus preventing pathogen attachment leading to their faster transport for longer distances. Laboratory column studies were carried out to investigate the effect of organic matter, in the form of dissolved organic carbon (DOC), on the transport of Escherichia coli and MS2 phage in saturated clean silica sand. Transport rates of these microbial tracers were also studied in a contaminated field site. Laboratory column studies showed that low concentrations (0.17 mg L −1 ) of DOC had little effect on E. coli J6-2 removal and slightly reduced the attachment of MS2 phage. After progressive conditioning of the column with DOC (1.7 mg L −1 and 17 mg L −1 ), neither E. coli J6-2 nor MS2 phage showed any attachment and recovery rates increased dramatically (up to 100%). The results suggest that DOC can affect the transport rates of microbial contaminants. For E. coli J6-2 the predominant effect appeared to be an increase in the secondary energy minimum leading to an increase in E. coli attachment initially. However, after 17 mg L −1 DOC conditioning of the silica sand no attachment of E. coli was observed as the DOC took up attachment sites in the porous media. MS2 phage appeared to be affected predominantly by out-competition of binding sites in the clean silica sand and a steady reduction in attachment was observed as the DOC conditioning increased. Field study showed a high removal of both E. coli and MS2 phage, although E. coli was removed at a lower rate than MS2 phage. In the field it is likely that a combination of effects are seen as the aquifer material will be heterogeneous in its surface nanoscale properties, demonstrated by the differing removal of E. coli and MS2 phage compared to the

  5. Transport of microbial tracers in clean and organically contaminated silica sand in laboratory columns compared with their transport in the field

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Louise, E-mail: louise.weaver@esr.cri.nz; Sinton, Lester W.; Pang, Liping; Dann, Rod; Close, Murray

    2013-01-15

    Waste disposal on land and the consequent transport of bacterial and viral pathogens in soils and aquifers are of major concern worldwide. Pathogen transport can be enhanced in the presence of organic matter due to occupation of attachment sites in the aquifer materials thus preventing pathogen attachment leading to their faster transport for longer distances. Laboratory column studies were carried out to investigate the effect of organic matter, in the form of dissolved organic carbon (DOC), on the transport of Escherichia coli and MS2 phage in saturated clean silica sand. Transport rates of these microbial tracers were also studied in a contaminated field site. Laboratory column studies showed that low concentrations (0.17 mg L{sup −1}) of DOC had little effect on E. coli J6-2 removal and slightly reduced the attachment of MS2 phage. After progressive conditioning of the column with DOC (1.7 mg L{sup −1} and 17 mg L{sup −1}), neither E. coli J6-2 nor MS2 phage showed any attachment and recovery rates increased dramatically (up to 100%). The results suggest that DOC can affect the transport rates of microbial contaminants. For E. coli J6-2 the predominant effect appeared to be an increase in the secondary energy minimum leading to an increase in E. coli attachment initially. However, after 17 mg L{sup −1} DOC conditioning of the silica sand no attachment of E. coli was observed as the DOC took up attachment sites in the porous media. MS2 phage appeared to be affected predominantly by out-competition of binding sites in the clean silica sand and a steady reduction in attachment was observed as the DOC conditioning increased. Field study showed a high removal of both E. coli and MS2 phage, although E. coli was removed at a lower rate than MS2 phage. In the field it is likely that a combination of effects are seen as the aquifer material will be heterogeneous in its surface nanoscale properties, demonstrated by the differing removal of E. coli and MS2 phage

  6. Aging effects on oil-contaminated Kuwaiti sand

    International Nuclear Information System (INIS)

    Al-Sanad, H.A.; Ismael, N.F.

    1997-01-01

    Large quantities of oil-contaminated sands resulted from the destruction of oil wells and the formation of oil lakes in Kuwait at the end of the Gulf Wa/r. A laboratory testing program was carried out to determine the geotechnical properties of this material and the effect of aging on their properties. Tests included direct shear, triaxial, and consolidation tests on clean and contaminated sand at the same relative density. The influence of aging was examined by testing uncontaminated sand after aging for one, three, and six months in natural environmental conditions. The results indicated increased strength and stiffness due to aging and a reduction of the oil content due to evaporation of volatile compounds. The factors that influence the depth of oil penetration in compacted sand columns were also examined including the type of oil, relative density, and the amount of fines

  7. Behavior of Hollow Thin Welded Tubes Filled with Sand Slag Concrete

    Directory of Open Access Journals (Sweden)

    Noureddine Ferhoune

    2016-01-01

    Full Text Available This paper presents the axial bearing capacity of thin welded rectangular steel stubs filled with concrete sand. A series of tests was conducted to study the behavior of short composite columns under axial compressive load; the cross section dimensions were 100 × 70 × 2 mm. A total of 20 stubs have been tested, as follows: 4 hollow thin welded tubes were tested to axial and eccentric load compression, 4 were filled with ordinary concrete appointed by BO columns, 6 were filled with concrete whose natural sand was completely substituted by a crystallized sand slag designated in this paper by BSI, and 6 were tucked in concrete whose natural sand was partially replaced by a crystallized sand slag called BSII. The main parameters studied are the height of the specimen (300 mm–500 mm, eccentricity of load and type of filling concrete. Based on test results obtained, it is confirmed that the length of the tubes has a considerable effect on the bearing capacity and the failure mode. In all test tubes, fracture occurred by the convex local buckling of steel section due to the outward thrust of the concrete; it was observed that the sand concrete improves the bearing capacity of tubes compounds compared to those filled with ordinary concrete.

  8. Characterization and testing of 30 kV, 60 kW electron optical column for melting applications

    Energy Technology Data Exchange (ETDEWEB)

    Baibhaw, Prakash; Gupta, Sachin; Malik, Pravanjan, E-mail: bprakash@barc.gov.in [Bhabha Atomic Research Centre, Mumbai (India)

    2014-07-01

    High energy electron beams (30-150 keV) are widely used as intense heat source in welding, melting and evaporation of refractory metals. These operations are mostly carried out in high vacuum (10{sup -4}-10{sup -5} mbar) to aid unimpeded flow of electrons from generation to the point of application. A 30 kV, 60 kW Electron beam optical column (EOC) is designed and developed under the high power beam technology programme. The optical column consists of an electron gun and twin electromagnetic focusing lenses. The heating power of emitter, gun perveance, grid voltage control, beam focusing with the twin electromagnetic lenses and beam spot size measurements are reported in this paper. The results are compared with the design values. Operational issues during the high power melting and the strategy for automation of the electron gun are discussed. (author)

  9. Time-Fractional Advection-Dispersion Equation (tFADE) to Quantify Aqueous Phase Contaminant Elution from a Trichloroethene (TCE) NAPL Source Zone in Sand Columns

    Science.gov (United States)

    Tick, G. R.; Wei, S.; Sun, H.; Zhang, Y.

    2016-12-01

    Pore-scale heterogeneity, NAPL distribution, and sorption/desorption processes can significantly affect aqueous phase elution and mass flux in porous media systems. The application of a scale-independent fractional derivative model (tFADE) was used to simulate elution curves for a series of columns (5 cm, 7 cm, 15 cm, 25 cm, and 80 cm) homogeneously packed with 20/30-mesh sand and distributed with uniform saturations (7-24%) of NAPL phase trichloroethene (TCE). An additional set of columns (7 cm and 25 cm) were packed with a heterogeneous distribution of quartz sand upon which TCE was emplaced by imbibing the immiscible liquid, under stable displacement conditions, to simulate a spill-type process. The tFADE model was able to better represent experimental elution behavior for systems that exhibited extensive long-term concentration tailing requiring much less parameters compared to typical multi-rate mass transfer models (MRMT). However, the tFADE model was not able to effectively simulate the entire elution curve for such systems with short concentration tailing periods since it assumes a power-law distribution for the dissolution rate for TCE. Such limitations may be solved using the tempered fractional derivative model, which can capture the single-rate mass transfer process and therefore the short elution concentration tailing behavior. Numerical solution for the tempered fractional-derivative model in bounded domains however remains a challenge and therefore requires further study. However, the tFADE model shows excellent promise for understanding impacts on concentration elution behavior for systems in which physical heterogeneity, non-uniform NAPL distribution, and pronounced sorption-desorption effects dominate or are present.

  10. Removal of COD and TSS From Dye Solution Using Sand Filtration and Adsorption

    Directory of Open Access Journals (Sweden)

    Heny Juniar

    2016-11-01

    Full Text Available This research was conducted in order to obtain proper compositions and the standard condition for the simple filtration equipments and optimum operational conditions in adsorption column. The research was carried out by analyzing parameters COD and TSS. The result showed that the process was able to reduced parameters observed from filtration step until the process in adsorptions column. The optimum conditions for sand filter equipment were 10 cm sand height, at least 7 cm fibers, 3-4 cm gravel. In the adsorption column, the optimum conditions for green waste water were flow rate at 40 ml/min 60 min adsorptions time, and 60 cm bed height. While purple for waste water; 20 mL/min of flowrate, 60 min of adsorption time, and the 60 cm of bed height

  11. Complex conductivity results to silver nanoparticles in partically saturated laboratory columns

    Data.gov (United States)

    U.S. Environmental Protection Agency — Laboratory complex conductivity data from partially saturated sand columns with silver nanoparticles. This dataset is not publicly accessible because: It involves...

  12. Formation of electrostatic double-layers and electron-holes in a low pressure mercury plasma column

    International Nuclear Information System (INIS)

    Petraconi, G; Maciel, Homero S

    2003-01-01

    Experimental studies of the formation of electrostatic double layers (DLs) and electron-holes (e-holes) are reported. The measurements were performed in the positive column of a mercury arc discharge operating in the low-pressure range of (2.0-14.0) x 10 -2 Pa with current density in the range of (3.0-8.0) x 10 3 A m -2 . Stable and unstable modes of the discharge were identified as the current was gradually increased, keeping constant the vapour pressure. The discharge remains stable until a critical current from which a slight increase of the current leads to an unstable regime characterized by high discharge impedance and strong oscillations. This mode ceased after a DL was formed in the plasma column. To induce the DL formation and to transport it smoothly along the discharge column, a low intensity B-field (7-10) x 10 -3 T produced by a movable single coil was used. The B-field locally increases the electron current density and makes the DL form at the centre of the magnetic constriction where it remained at rest. Electrostatic potential structures compatible with ordinary DLs and multiple-layers could be formed in the plasma column by dealing with the combined effects of the operational parameters of the discharge. It is noticeable that a pure e-hole, which is a symmetric triple-layer having a bell shape potential profile, could easily be formed by means of this experimental technique. A partial kinetic description, based on the space charge structure derived from an experimental e-hole, is presented in order to infer the charged particle populations that could contribute to the space charge of the e-hole. Evidence is shown that strong e-hole formation might be driven by an ion beam, therefore it could not be formed in isolation since its formation requires a nearby ion accelerating potential structure. Probe measurements of the plasma properties, at various radial positions of the stable positive column, are also presented. In the stable mode, prior to

  13. Dynamic shear stiffness and damping ratio of marine calcareous and siliceous sands

    Science.gov (United States)

    Javdanian, Hamed; Jafarian, Yaser

    2018-03-01

    Shear stiffness and damping ratio of two marine calcareous and siliceous sands were evaluated through an experimental program. Resonant column and cyclic triaxial experiments were conducted to measure the dynamic properties of the sands in small and large shear strain amplitudes. The tests were conducted under various initial stress-density conditions. The influence of effective confining pressure on the dynamic properties of the sands was assessed and compared in a preceding paper. It was shown that the calcareous sand has higher shear stiffness and lower damping ratio in comparison to the siliceous sand. In this note, the results are presented in more details and the dynamic behavior curves of the studied sands are compared with some available models, mostly developed based on the laboratory data of siliceous sands. This comparative study reveals that the previous models predict the dynamic properties of the calcareous sand in less precision than those of the siliceous sand.

  14. Numerical analysis of stone columns in mitigating liquefaction effects in embankment fills

    Energy Technology Data Exchange (ETDEWEB)

    Borghei, Z.; Soroush, A. [Amirkabir University of Technology, Tehran, (Iran, Islamic Republic of); Noorzad, A. [Power and Water University of Technology, Tehran, (Iran, Islamic Republic of)

    2010-07-01

    The traditional approach to liquefaction in embankment fills is to use in-situ densification. The use of stone columns offers the possibility of preventing liquefaction and associated settlements while reducing the cost and time required for treatment. This paper investigated the behaviour of stone columns using a numerical method. The study focused on a case study, a sand layer beneath two wall tanks, butane and propane NGL, located on Siri Island, Persian Gulf, Iran. Numerical analyses were carried out to evaluate the rate of excess pore pressure build-up in the improved ground. The numerical model results were compared to the simulation results from a centrifuge test for a uniform 19m-thick liquefiable sand layer. The numerical methodology was verified. The results showed that the stone columns can significantly increase the rate of pore pressure dissipation and reduce the settlement. It was found that the installation process densifies the surrounding soil, decreasing the liquefaction potential.

  15. Significance of Iron(II,III) Hydroxycarbonate Green Rust in Arsenic Remediation Using Zerovalent Iron in Laboratory Column Tests

    Science.gov (United States)

    We examined the corrosion products of zerovalent iron used in three column tests for removing arsenic from water under dynamic flow conditions. Each column test lasted three- to four-months using columns consisting of a 10.3-cm depth of 50 : 50 (w : w, Peerless iron : sand) in t...

  16. 2D fall of granular columns controlled by slow horizontal withdrawal of a retaining wall

    Science.gov (United States)

    Mériaux, C. A.

    2006-12-01

    This paper describes a series of experiments designed to investigate the fall of granular columns in quasi- static regime. Columns made of alternatively green and red sand layers were initially laid out in a box and then released when a retaining wall was set in slow motion with constant speed. The dependence of the dynamics of the fall on the initial aspect ratio of the columns, the velocity of the wall and the material properties was investigated within the quasi-static regime. A change in the behaviour of the columns was identified to be a function of the aspect ratio (height/length) of the initial sand column. Columns of high aspect ratio first subsided before sliding along failure planes, while columns of small aspect ratio were only observed to slide along failure planes. The transition between these two characteristic falls occurred regardless of the material and the velocity of the wall in the context of the quasi-static regime. When the final height and length of the piles were analyzed, we found power-law relations of the ratio of initial to final height and final run-out to initial length with the aspect ratio of the column. The dissipation of energy is also shown to increase with the run-out length of the pile until it reaches a plateau.

  17. Seabed gallery intakes: Investigation of the water pretreatment effectiveness of the active layer using a long-term column experiment

    KAUST Repository

    Dehwah, Abdullah

    2017-05-11

    Seabed gallery intake systems used for seawater reverse osmosis facilities employ the same principle of water treatment as slow sand filtration in freshwater systems. An investigation concerning the effectiveness of the active layer (top layer) in improving raw water quality was conducted by using a long-term bench-scale columns experiment. Two different media types, silica and carbonate sand, were tested in 1 m columns to evaluate the effectiveness of media type in terms of algae, bacteria, Natural Organic Matter (NOM) and Transparent Exopolymer Particles (TEP) removal over a period of 620 days. Nearly all algae in the silica sand column, 87% (σ = 0.04) of the bacteria, 59% (σ = 0.11) of the biopolymer fraction of NOM, 59% (σ = 0.16) of particulate and 32% (σ = 0.25) of colloidal TEP were removed during the last 330 days of the experiment. Total removal was observed in the carbonate sand column for algal concentration, while the bacterial removal was lower at 74% (σ = 0.08). Removal of biopolymers, particulate and colloidal TEP were higher in the carbonate column during the last 330 days with 72% (σ = 0.15), 66% (σ = 0.08) and 36% (σ = 0.12) removed for these organics respectively. Removal of these key organics through the 1 m thick column, representing the active layer, will likely reduce the rate of biofouling, reduce chemical usage and minimize operating cost in SWRO systems. The data show that the media will require several months at the beginning of operation to reach equilibrium so that high organic removal rates can be achieved. No development of a “schmutzdecke” layer occurred. The experimental results suggest that unlike freshwater slow sand filtration wherein most water treatment occurs in the upper 10 cm, in seawater systems treatment occurs throughout the full active layer depth of 1 m. The results of this study will help in designing and operating seabed gallery intake systems in varied geological conditions.

  18. Neutron flux measurement in the thermal column of the Malaysian TRIGA mark II reactor with MCNP verification

    International Nuclear Information System (INIS)

    Abdel Munem, E.; Shukri, A.; Tajuddin, A.A.

    2006-01-01

    A study of the thermal column of the Malaysian TRIGA Mark II reactor, forming part of a feasibility study for BNCT was proposed in 2001. In the current study, pure metals were used to measure the neutron flux at selected points in the thermal column and the neutron flux determined using SAND-II. Monte Carlo simulation of the thermal column was also carried out. The reactor core was homogenized and calculations of the neutron flux through the graphite stringers performed using MCNP5. The results show good agreement between the measured flux and the MCNP calculated flux. An obvious extension from this is that the MCNP neutron flux output can be utilized as an input spectrum for SAND-II for the flux iteration. (author)

  19. Period doubling of azimuthal oscillations on a non-neutral magnetized electron column

    International Nuclear Information System (INIS)

    Boswell, R.W.

    1985-01-01

    The low-frequency azimuthal oscillations on a non-neutral magnetized electron column of very low density are investigated. A perturbation analysis of the slow mode of the rigid rotator equilibrium is developed to illustrate the nature of large-amplitude fundamental-mode oscillations. The results of this theoretical analysis show two important characteristics: firstly, as the perturbation amplitude is increased the wave form ceases to be purely sinusoidal and shows period doubling. Secondly, above a certain threshold, all harmonics of the wave grow and the wave breaks. The results of the former are compared with a simple electron beam experiment and are found to be in good qualitative agreement. (author)

  20. End shape effects on the mθ=1 diocotron instability in hollow electron columns

    International Nuclear Information System (INIS)

    Kabantsev, A. A.; Driscoll, C. F.

    1999-01-01

    Magnetically confined hollow columns of electrons exhibit a robust exponential m θ =1 diocotron instability, whereas standard 2-D fluid theory predicts at most algebraic growth. This discrepancy suggests that experimental subtleties such as finite axial length of the plasma column must be considered. Here, we present a systematic analysis of our experiments to determine the detailed influence of the plasma end curvature on the observed diocotron instability. Observed dependencies of unstable mode frequency, growth rate and spatial eigenfunction as a function of the plasma end curvature are in quantitative (factor-of-two) agreement with recent quasi-2D extension of the fluid theory

  1. Batch and column studies of adsorption of Li, Ni and Br by a reference sand for contaminant transport experiments

    International Nuclear Information System (INIS)

    Seigel, M.D.; Ward, D.B.; Bryan, C.R.

    1995-09-01

    A processed quartz sand (Wedron 510), mined from the St. Peter sandstone, has been characterized by a variety of chemical and physical methods for use as a reference porous media in transport model validation experiments. Wedron 510 sand was used in an intermediate-scale experiment involving migration of Ni, Li and Br through a 6-m high x 3-m diameter caisson. Ni and Li adsorption/desorption, and Li/Ni site-competition experiments yielded information on the importance of the trace mineral phases to adsorption of Li and Ni by the sand. The presence of an iron hydroxide coating similar to goethite on the sand grains is suggested by visual observation and leaching experiments. Kaolinite was identified by SEM and XRD as a significant trace mineral phase in the sand and occurs as small particles coating the sand grains. Quartz, the predominant constituent of the sand by weight, does not appear to contribute significantly to the adsorption properties of the sand. Qualitatively, the adsorption properties of the sand can be adequately modeled as a two-mineral system (goethite and kaolinite). The studies described in this report should provide a basis for understanding transport of Ni, Li and Br through porous media similar to the reference sand. Techniques were developed for obtaining parameter values for surface complexation and kinetic adsorption models for the sand and its mineral components. These constants can be used directly in coupled hydrogeochemical transport codes. The techniques should be useful for characterization of other natural materials and elements in high-level nuclear waste in support of coupled hydrogeochemical transport calculations for Yucca Mountain

  2. Numerical analysis of biological clogging in two-dimensional sand box experiments

    DEFF Research Database (Denmark)

    Kildsgaard, J.; Engesgaard, Peter Knudegaard

    2001-01-01

    Two-dimensional models for biological clogging and sorptive tracer transport were used to study the progress of clogging in a sand box experiment. The sand box had been inoculated with a strip of bacteria and exposed to a continuous injection of nitrate and acetate. Brilliant Blue was regularly...... injected during the clogging experiment and digital images of the tracer movement had been converted to concentration maps using an image analysis. The calibration of the models to the Brilliant Blue observations shows that Brilliant Blue has a solid biomass dependent sorption that is not compliant...... with the assumed linear constant Kd behaviour. It is demonstrated that the dimensionality of sand box experiments in comparison to column experiments results in a much lower reduction in hydraulic conductivity Žfactor of 100. and that the bulk hydraulic conductivity of the sand box decreased only slightly. However...

  3. Adhesion to sand and ability to mineralise low pesticide concentrations are required for efficient bioaugmentation of flow-through sand filters

    DEFF Research Database (Denmark)

    Samuelsen, Elin Djurhuus; Badawi, Nora; Nybroe, Ole

    2017-01-01

    (Sphingomonas sp. PM2, Sphingomonas sp. ERG5, Burkholderia sp. TFD34, Cupriavidus sp. TFD38) were characterised with regard to their motility, cell surface hydrophobicity, biofilm formation, adhesion behaviour and ability to mineralise MCPA. Strains PM2 and ERG5 were non-motile and hydrophobic, whilst strains...... TFD34 and TFD38 were motile and less hydrophobic. All the strains except ERG5 showed low biofilm formation on polystyrene, although it was significantly higher on glass. PM2 was the most efficient MCPA degrader as it displayed no lag phase and reached >50 % mineralisation at all concentrations (0.......0016-25 mg L(-1)). PM2 adhered significantly better to sand than the other strains. No link was found between motility, biofilm formation and the ability to adhere to sand. PM2 completely removed MCPA for 14 days when inoculated in sand columns with a constant inlet of 1 mg L(-1) MCPA. These results...

  4. Modelling the removal of p-TSA (para-toluenesulfonamide) during rapid sand filtration used for drinking water treatment.

    Science.gov (United States)

    Meffe, Raffaella; Kohfahl, Claus; Holzbecher, Ekkehard; Massmann, Gudrun; Richter, Doreen; Dünnbier, Uwe; Pekdeger, Asaf

    2010-01-01

    A finite element model was set-up to determine degradation rate constants for p-TSA during rapid sand filtration (RSF). Data used for the model originated from a column experiment carried out in the filter hall of a drinking water treatment plant in Berlin (Germany). Aerated abstracted groundwater was passed through a 1.6m long column-shaped experimental sand filter applying infiltration rates from 2 to 6mh(-1). Model results were fitted to measured profiles and breakthrough curves of p-TSA for different infiltration rates using both first-order reaction kinetics and Michaelis-Menten kinetics. Both approaches showed that degradation rates varied both in space and time. Higher degradation rates were observed in the upper part of the column, probably related to higher microbial activity in this zone. Measured and simulated breakthrough curves revealed an adaption phase with lower degradation rates after infiltration rates were changed, followed by an adapted phase with more elevated degradation rates. Irrespective of the mathematical approach and the infiltration rate, degradation rates were very high, probably owing to the fact that filter sands have been in operation for decades, receiving high p-TSA concentrations with the raw water.

  5. The influence of moisture content of sand on leach rates from cement and bitumen radioactive waste forms in a shallow ground repository

    International Nuclear Information System (INIS)

    Lovasic, Z.; Torok, J.; Buckley, L.P.

    1992-11-01

    Leaching rates from cement and bitumen-conditioned waste in contact with sand were determined with different water content of the sand up to and including saturation. A cylindrical waste form occupied one end of a column, with sand packed in the remainder. Axial radionuclide concentration profiles in the columns were determined several times during the experiment using an automated system consisting of a gamma spectrometer and an optical bench. The migration of 85 Sr, 137 Cs and 60 Co was determined from concentration profiles with time. The diffusion coefficient for 137 Cs in cement varied more than expected with the change of moisture content of sand. The leaching of bitumen waste forms is complex, and has poor reproducibility. When the water content of the sand was below 0.067 mL/mL, no leaching was determined from bitumen waste forms in all of the specimens except one. No clear relationship could be established between leach rate and the water content of sand above 0.18 mL/mL water content

  6. Two dimensional fall of granular columns controlled by slow horizontal withdrawal of a retaining wall

    Science.gov (United States)

    Mériaux, Catherine

    2006-09-01

    This paper describes a series of experiments designed to investigate the fall of granular columns in a quasi-static regime. Columns made of alternatively green and red sand layers were initially laid out in a box and then released when a retaining wall was set in slow motion with constant speed. The dependence of the dynamics of the fall on the initial aspect ratio of the columns, the velocity of the wall, and the material properties was investigated within the quasi-static regime. A change in the behavior of the columns was identified to be a function of the aspect ratio (height/length) of the initial sand column. Columns of high aspect ratio first subsided before sliding along failure planes, while columns of small aspect ratio were only observed to slide along failure planes. The transition between these two characteristic falls occurred regardless of the material and the velocity of the wall in the context of the quasi-static regime. When the final height and length of the piles were analyzed, we found power-law relations of the ratio of initial to final height and final run-out to initial length with the aspect ratio of the column. The dissipation of energy is also shown to increase with the run-out length of the pile until it reaches a plateau. Finally, we find that the structure of the slip planes that develop in our experiments are not well described by the failure of Coulomb's wedges for twin retaining rough walls.

  7. Seabed gallery intakes: Investigation of the water pretreatment effectiveness of the active layer using a long-term column experiment

    KAUST Repository

    Dehwah, Abdullah; Missimer, Thomas M.

    2017-01-01

    ) in improving raw water quality was conducted by using a long-term bench-scale columns experiment. Two different media types, silica and carbonate sand, were tested in 1 m columns to evaluate the effectiveness of media type in terms of algae, bacteria, Natural

  8. Nonlocal electron kinetics and spectral line emission in the positive column of an argon glow discharge

    International Nuclear Information System (INIS)

    Golubovskii, Yu; Kalanov, D; Gorchakov, S; Uhrlandt, D

    2015-01-01

    Modern non-local electron kinetics theory predicts several interesting effects connected with spectral line emission from the positive column in the range of low and medium pressures and currents. Some theoretical works describe non-monotonic behavior of the radial profiles of line emission at intermediate pressures and currents between the validity ranges of the non-local and local approximation of the electron kinetics. Despite a great number of publications, there have been no systematic measurements attempting to confirm these theoretical predictions through experiments. In this work the radial profiles of the line emission from the positive column of an argon glow discharge have been measured with high spatial resolution and new effects caused by the narrowing and broadening of the spatial emission profiles with dependence on discharge conditions have been discovered. The effect of intensity maximum shift predicted by theory using a self-consistent model was not found in the experiment. The properties of the spectral line radiation are influenced by the peculiarities of the formation of the high-energy tail of the electron energy distribution function. An interpretation of the observed effects based on the non-local character of the electron kinetics in radially inhomogeneous fields is given. The obtained experimental data are compared with the results of calculations. (paper)

  9. Fate of parabens and 4-hydroxybenzoic acid in aquifer materials columns during step experiments with fresh and sea waters

    Science.gov (United States)

    López-Ortiz, C. M.; Boluda-Botella, N.; Prats-Rico, D.; Sentana-Gadea, I.

    2018-02-01

    Coastal areas submitted to seawater intrusion and with discharges from urban and industrial wastewaters, municipal landfill leachates, rivers, recreational waters and other sources are sensitive to be polluted with parabens. Understanding the fate of these compounds in environmental studies, it requires previously the knowledge of the reactive processes in controlled conditions. In this research, laboratory columns experiments were carried out with a group of parabens (methyl-, ethyl-, propyl- and butylparaben) and their main degradation compound (4-hydroxybenzoic acid) to study mainly the dynamic sorption processes in different aquifer materials (100% sand and heterogeneous: 81% sand, 9% silt and 10% clay) and with fresh and sea waters, the end members of seawater intrusions. To the column hydrodynamic characterization, tracer assays with increase and decrease of salinity were performed, to obtain the mean residence time of each column and other transport parameters which allow us to compare parabens' sorption in different conditions. The results of the adsorption and desorption of parabens in the sand column demonstrated be fast and simultaneous, with a short delay and without influence of the water salinity. Very different results were found in the column experiments with heterogeneous material, where the presence of clay and organic matter increase the time of adsorption/desorption as the length of the alkyl chain paraben increased, according with their hydrophobicity. It should be noted that despite the quick desorption of the major quantities of parabens, the elution of their trace concentrations was very slow (for the seawater, the buthylparaben required a dimensionless time of 800). Planning the restoration of a coastal aquifer with freshwater, and in the conditions of the studied sand column experiment, it will need a dimensionless time of 160. However, it is necessary to take into account that the studied parabens and 4-hydroxybenzoic acid are

  10. Column study for the evaluation of the transport properties of polyphenol-coated nanoiron.

    Science.gov (United States)

    Mystrioti, C; Papassiopi, N; Xenidis, A; Dermatas, D; Chrysochoou, M

    2015-01-08

    Injection of a nano zero valent iron (nZVI) suspension in the subsurface is a remedial option for obtaining the in situ reduction and immobilization of hexavalent chromium in contaminated aquifers. Prerequisite for the successful implementation of this technology is that the nanoparticles form a stable colloidal suspension with good transport properties when delivered in the subsurface. In this study we produced stable suspensions of polyphenol-coated nZVI (GT-nZVI) and we evaluated their transport behavior through representative porous media. Two types of porous materials were tested: (a) silica sand as a typical inert medium and (b) a mixture of calcareous soil and sand. The transport of GT-nZVI through the sand column was effectively described using a classic 1-D convection-dispersion flow equation (CDE) in combination with the colloid filtration theory (CFT). The calculations indicate that nZVI travel distance will be limited in the range 2.5-25cm for low Darcy velocities (0.1-1m/d) and in the order of 2.5m at higher velocities (10m/d). The mobility of GT-nZVI suspension in the soil-sand column is lower and is directly related to the progress of the neutralization reactions between the acidic GT-nZVI suspension and soil calcite. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. The mobility of indium and gallium in groundwater systems: constraining the role of sorption in sand column experiments

    Science.gov (United States)

    Dror, I.; Ringering, K.; Yecheskel, Y.; Berkowitz, B.

    2017-12-01

    The mobility of indium and gallium in groundwater environments was studied via laboratory experiments using quartz sand as a porous medium. Indium and gallium are metals of very low abundance in the Earth's crust and, correspondingly, the biosphere is only adapted to very small concentrations of these elements. However, in modern semiconductor industries, both elements play a central role and are incorporated in devices of mass production such as smartphones and digital cameras. The resulting considerable increase in production, use and discharge of indium and gallium throughout the last two decades, with a continuous and fast increase in the near future, raises questions regarding the fate of both elements in the environment. However, the transport behavior of these two metals in soils and groundwater systems remains poorly understood to date. Because of the low solubility of both elements in aqueous solutions, trisodium citrate was used as a complexation agent to stabilize the solutions, enabling investigation of the transport of these metals at neutral pH. Column experiments showed different binding capacities for indium and gallium, where gallium is much more mobile compared to indium and both metals are substantially retarded in the column. Different affinities were also confirmed by examining sorption isotherms of indium and gallium in equilibrium batch systems. The effect of natural organic matter on the mobility of indium and gallium was also studied, by addition of humic acid. For both metals, the presence of humic acid affects the sorption dynamics: for indium, sorption is strongly inhibited leading to much higher mobility, whereas gallium showed a slightly higher sorption affinity and very similar mobility compared to the same setup without humic acid addition. However, in all cases, the binding capacity of gallium to quartz is much weaker than that of indium. These results are consistent with the assumption that indium and gallium form different types

  12. A column experiment for the study of colloidal radionuclide migration in Gorleben aquifer systems

    International Nuclear Information System (INIS)

    Kim, J.I.; Delakowitz, B.; Zeh, P.; Klotz, D.; Lazik, D.

    1994-01-01

    A column experiment is performed for the assessment of the migration behaviour of trivalent 152 Eu, 241 Am and tetra- and pentavalent 237 Np, 233 Pa in the presence of humic colloids. Groundwater of an organic rich aquifer from the geological site at Gorleben is chosen for the experiment, as this has been well characterized during the earlier work and contains a substantial amount of humic colloids. The chemical and mineralogical composition of the pleistocene quartz-sand used in the column experiment is characterized by various analytical and mineralogical methods. Prior to the actinide migration experiment, the hydraulic properties (flow velocity, effective porosity, longitudinal dispersion coefficient) are determined in order to ascertain stable conditions for the experiment. In addition, the microstructure parameters (sediment surface, pore size distribution) of the groundwater-sand system in the column are determined. Radiotracers used for the determination of the hydraulic properties are 3 HHO and 82 Br - . Results obtained to date indicate a relatively high mobility of the lanthanide and actinide ions loaded on aquatic humic colloids. The recovery of injected radiotracer ions in eluates is found to depend on the flow velocity of groundwater through the column. The results help to elucidate the actinide migration behaviour in the presence of natural humic colloids. (orig.)

  13. Sustainable materials used as stone column filler: A short review

    Science.gov (United States)

    Zukri, Azhani; Nazir, Ramli

    2018-04-01

    Stone columns (also known as granular piles) are one of the methods for soft soil stabilization and typically used to increase bearing capacity and stability of slope.; Apart from decreasing the compressibility of loose and fine graded soils, it also accelerates the consolidation effect by improving the drainage path for pore water pressure dissipation and reduces the liquefaction potential of soils during earthquake event. Stone columns are probably the most “natural” ground treatment method or foundation system in existence to date. The benefit of stone columns is owing to the partial replacement of compressible soil by more competent materials such as stone aggregate, sand and other granular materials. These substitutes also act as reinforcement material, hence increasing overall strength and stiffness of the soft soil. Nowadays, a number of research has been conducted on the behaviour and performance of stone columns with various materials utilized as column filler replacing the normal aggregate. This paper will review extensively on previously conducted research on some of the materials used as stone column backfill materials, its suitability and the effectiveness as a substitute for regular aggregates in soft soil improvement works.

  14. Fate of triclocarban during soil aquifer treatment: Soil column studies

    KAUST Repository

    Essandoh, H. M K

    2010-04-01

    There are current concerns about the presence of persistent chemicals in recharge water used in soil aquifer treatment systems. Triclocarban (TCC) has been reported as a persistent, high production volume chemical with the potential to bioaccumulate in the environment. It is also known to have adverse effects such as toxicity and suspected endocrine disruption. This study was carried out to study the fate of TCC in soil aquifer treatment (SAT) through laboratory simulations in a soil column. The system performance was evaluated with regards to TCC influent concentration, sand (column) depth, and residence time. Results obtained confirmed the ability of SAT to reduce TCC concentrations in wastewater. Sorption and biodegradation were responsible for TCC removal, the latter mechanism however being unsustainable. The removal efficiency was found to be dependent on concentration and decreased over time and increased with column depth. Within the duration of the experimental run, TCC negatively impacted on treatment performance through a reduction in COD removals observed in the column. © IWA Publishing 2010.

  15. Influence green sand system by core sand additions

    Directory of Open Access Journals (Sweden)

    N. Špirutová

    2012-01-01

    Full Text Available Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this contribution is: “How the green sand systems are influenced by core sands?”This effect is considered by determination of selected technological properties and degree of green sand system re-bonding. From the studies, which have been published yet, there is not consistent opinion on influence of core sand dilution on green sand system properties. In order to simulation of the effect of core sands on the technological properties of green sands, there were applied the most common used technologies of cores production, which are based on bonding with phenolic resin. Core sand concentration added to green sand system, was up to 50 %. Influence of core sand dilution on basic properties of green sand systems was determined by evaluation of basic industrial properties: moisture, green compression strength and splitting strength, wet tensile strength, mixture stability against staling and physical-chemistry properties (pH, conductivity, and loss of ignition. Ratio of active betonite by Methylene blue test was also determined.

  16. Retention of radium from thermal waters on sand filters and adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Elejalde, C. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain)]. E-mail: inpelsac@bi.ehu.es; Herranz, M. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Idoeta, R. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Legarda, F. [Dpto. de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Romero, F. [Dpto. de Ingenieria Quimica y del Medio Ambiente, Escuela Tecnica Superior de Ingenieria, Alameda de Urquijo s/n, 48013 Bilbao (Spain); Baeza, A. [Dpto. de Fisica, Facultad de Veterinaria, Universidad de Extremadura, Avda. Universidad s/n, 10071 Caceres (Spain)

    2007-06-18

    This study was focussed on laboratory experiences of retention of radium from one thermal water on sand filters and adsorbents, trying to find an easy method for the elimination in drinkable waters polluted with this natural radio-nuclide. A thermal water from Cantabria (Spain) was selected for this work. Retention experiences were made with columns of 35 mm of diameter containing 15 cm layers of washed river sand or 4 cm layers of zeolite A3, passing known volumes of thermal water at flows between 4 and 40 ml/min with control of the retained radium by determining the amount in the water after the treatment. The statistical analysis of data suggests that retention depends on the flow and the volume passed through the columns. As additional adsorbents were used kaolin and a clay rich in illite. Jar-test experiences were made agitating known weights of adsorbents with the selected thermal water, with addition of flocculants and determination of radium in filtrated water after the treatment. Data suggest that retention is related to the weight of adsorbent used, but important quantities of radium seem remain in solution for higher amounts of adsorbents, according to the statistical treatment of data. The elution of retained radium from columns or adsorbents, previously used in experiences, should be the aim of a future research.

  17. Retention of radium from thermal waters on sand filters and adsorbents

    International Nuclear Information System (INIS)

    Elejalde, C.; Herranz, M.; Idoeta, R.; Legarda, F.; Romero, F.; Baeza, A.

    2007-01-01

    This study was focussed on laboratory experiences of retention of radium from one thermal water on sand filters and adsorbents, trying to find an easy method for the elimination in drinkable waters polluted with this natural radio-nuclide. A thermal water from Cantabria (Spain) was selected for this work. Retention experiences were made with columns of 35 mm of diameter containing 15 cm layers of washed river sand or 4 cm layers of zeolite A3, passing known volumes of thermal water at flows between 4 and 40 ml/min with control of the retained radium by determining the amount in the water after the treatment. The statistical analysis of data suggests that retention depends on the flow and the volume passed through the columns. As additional adsorbents were used kaolin and a clay rich in illite. Jar-test experiences were made agitating known weights of adsorbents with the selected thermal water, with addition of flocculants and determination of radium in filtrated water after the treatment. Data suggest that retention is related to the weight of adsorbent used, but important quantities of radium seem remain in solution for higher amounts of adsorbents, according to the statistical treatment of data. The elution of retained radium from columns or adsorbents, previously used in experiences, should be the aim of a future research

  18. Experimental Evidence that Abrasion of Carbonate Sand is a Significant Source of Carbonate Mud

    Science.gov (United States)

    Trower, L.; Kivrak, L.; Lamb, M. P.; Fischer, W. W.

    2017-12-01

    Carbonate mud is a major sedimentary component of modern and ancient tropical carbonate environments, yet its enigmatic origin remains debated. Early views on the origin of carbonate mud considered the abrasion of carbonate sand during sediment transport as a possible mechanism. In recent decades, however, prevailing thought has generally settled on a binary explanation: 1) precipitation of aragonite needles within the water column, and 2) post-mortem dispersal of biological aragonite, in particular from algae, and perhaps aided by fish. To test these different hypotheses, we designed a model and a set of laboratory experiments to quantify the rates of mud production associated with sediment transport. We adapted a recent model of ooid abrasion rate to predict the rate of mud production by abrasion of carbonate sand as a function of grain size and sediment transport mode. This model predicts large mud production rates, ranging from 103 to 104 g CaCO3/m2/yr for typical grain sizes and transport conditions. These rate estimates are at least one order of magnitude more rapid than the 102 g CaCO3/m2/yr estimates for other mechanisms like algal biomineralization, indicating that abrasion could produce much larger mud fluxes per area as other mechanisms. We tested these estimates using wet abrasion mill experiments; these experiments generated mud through mechanical abrasion of both ooid and skeletal carbonate sand for grain sizes ranging from 250 µm to >1000 µm over a range of sediment transport modes. Experiments were run in artificial seawater, including a series of controls demonstrating that no mud was produced via homogenous nucleation and precipitation in the absence of sand. Our experimental rates match the model predictions well, although we observed small systematic differences in rates between abrasion ooid sand and skeletal carbonate sand that likely stems from innate differences in grain angularity. Electron microscopy of the experimental products revealed

  19. Characterize Behaviour of Emerging Pollutants in Artificial Recharge: Column Experiments - Experiment Design and Results of Preliminary Tests

    Science.gov (United States)

    Wang, H.; Carrera, J.; Ayora, C.; Licha, T.

    2012-04-01

    Emerging pollutants (EPs) have been detected in water resources as a result of human activities in recent years. They include pharmaceuticals, personal care products, dioxins, flame retardants, etc. They are a source of concern because many of them are resistant to conventional water treatment, and they are harmful to human health, even in low concentrations. Generally, this study aims to characterize the behaviour of emerging pollutants in reclaimed water in column experiments which simulates artificial recharge. One column set includes three parts: influent, reactive layer column (RLC) and aquifer column (AC). The main influent is decided to be Secondary Effluent (SE) of El Prat Wastewater Treatment Plant, Barcelona. The flow rate of the column experiment is 0.9-1.5 mL/min. the residence time of RLC is designed to be about 1 day and 30-40 days for AC. Both columns are made of stainless steel. Reactive layer column (DI 10cm * L55cm) is named after the filling material which is a mixture of organic substrate, clay and goethite. One purpose of the application of the mixture is to increase dissolve organic carbon (DOC). Leaching test in batchs and columns has been done to select proper organic substrate. As a result, compost was selected due to its long lasting of releasing organic matter (OM). The other purpose of the application of the mixture is to enhance adsorption of EPs. Partition coefficients (Kow) of EPs indicate the ability of adsorption to OM. EPs with logKow>2 could be adsorbed to OM, like Ibuprofen, Bezafibrate and Diclofenac. Moreover, some of EPs are charged in the solution with pH=7, according to its acid dissociation constant (Ka). Positively charged EPs, for example Atenolol, could adsorb to clay. In the opposite, negatively charged EPs, for example Gemfibrozil, could adsorb to goethite. Aquifer column (DI 35cm * L1.5m) is to simulate the processes taking place in aquifer in artificial recharge. The filling of AC has two parts: silica sand and

  20. Effect of bioremediation agents on oil biodegradation in medium-fine sand

    International Nuclear Information System (INIS)

    Croft, B.C.; Swannell, R.P.J.; Grant, A.L.; Lee, K.

    1995-01-01

    A spill of weathered Arabian light crude oil on an intertidal sand zone was simulated in the laboratory. Respirometry, chemical, and microbiological methods were employed to assess the effectiveness of two bioremediation agents: a slow-release inorganic (Max Bac) and an oleophilic organic fertilizer (Inipol EAP22). Inipol EAP22 stimulated additional CO 2 evolution, and significantly increased both the total chemoheterotrophic population and the number of hydrocarbon-degrading microorganisms. At the end of the experiment, the residual oil extracted from the Inipol-treated sand was significantly more biodegraded, based on the application of the conserved biomarkers (phytane and 17α, 21β hopane), than that removed from the other sand columns, albeit by a relatively small amount. The results suggested that Inipol EAP22 stimulated the chemoheterotrophic and hydrocarbon-degrading microbial population and, after a lag phase, encouraged oil biodegradation in fine sandy sediments subjected to a vertical tidal cycle

  1. Sorption, desorption and extraction of uranium from some sands under dynamic conditions

    International Nuclear Information System (INIS)

    Palagyi, S.; Laciok, A.

    2006-01-01

    Sorption, desorption and extraction behavior of uranium in various fluvial sands of domestic origin were investigated in continuous dynamic column experiments. For the sorption of U(VI) an aqueous 10 -4 M UO 2 (NO 3 ) 2 solution was used at a flow rate of about 0.3 cm 3 /min. Desorption was carried out with demineralized water, and the extraction with 10 -2 M Na 2 CO 3 solution following desorption. The retardation coefficients (R) and hydrodynamic dispersion coefficients (D d ), were determined using an ADE equation. From the experimentally determined values of R, bulk density and porosity, the distribution coefficients (K d ) of the UO 2 2+ species have been calculated for the respective processes. The extent of U sorption in sands, as well as the proportion of desorbed and extracted U from these sands, was also calculated. (author)

  2. Laser characterisation of a 3D single-type column p-type prototype module read out with ATLAS SCT electronics

    International Nuclear Information System (INIS)

    Ehrich, T.; Kuehn, S.; Boscardin, M.; Dalla Betta, G.-F.; Eckert, S.; Jakobs, K.; Maassen, M.; Parzefall, U.; Piemonte, C.; Pozza, A.; Ronchin, S.; Zorzi, N.

    2007-01-01

    In this paper measurements of a 3D single-type column (3D-stc) microstrip silicon device are shown. The 3D-stc sensor has n-type columns in p-type substrate. It has been connected to an ATLAS SCT ABCD3T chip and is readout with ATLAS SCT electronics at 40 MHz. Spatial measurements were done with a laser setup to investigate the expected low field region in 3D devices. An influence of the p-stops on the collected charge has been observed

  3. Laser characterisation of a 3D single-type column p-type prototype module read out with ATLAS SCT electronics

    Energy Technology Data Exchange (ETDEWEB)

    Ehrich, T. [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder Str. 3, 79104 Freiburg (Germany); Kuehn, S. [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder Str. 3, 79104 Freiburg (Germany)], E-mail: susanne.kuehn@physik.uni-freiburg.de; Boscardin, M.; Dalla Betta, G.-F. [ITC-irst Trento, Microsystems Division, via Sommarive, 18 38050 Povo di Trento (Italy); Eckert, S.; Jakobs, K.; Maassen, M.; Parzefall, U. [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder Str. 3, 79104 Freiburg (Germany); Piemonte, C.; Pozza, A.; Ronchin, S.; Zorzi, N. [ITC-irst Trento, Microsystems Division, via Sommarive, 18 38050 Povo di Trento (Italy)

    2007-12-11

    In this paper measurements of a 3D single-type column (3D-stc) microstrip silicon device are shown. The 3D-stc sensor has n-type columns in p-type substrate. It has been connected to an ATLAS SCT ABCD3T chip and is readout with ATLAS SCT electronics at 40 MHz. Spatial measurements were done with a laser setup to investigate the expected low field region in 3D devices. An influence of the p-stops on the collected charge has been observed.

  4. BENTONITE-QUARTZ SAND AS THE BACKFILL MATERIALS ON THE RADIOACTIVE WASTE REPOSITORY

    Directory of Open Access Journals (Sweden)

    Raharjo Raharjo

    2010-06-01

    Full Text Available An investigation of the contribution of quartz sand in the bentonite mixture as the backfill materials on the shallow land burial of radioactive waste has been done. The experiment objective is to determine the effect of quartz sand in a bentonite mixture with bentonite particle sizes of -20+40, -40+60, and -60+80 mesh on the retardation factor and the uranium dispersion in the simulation of uranium migration in the backfill materials. The experiment was carried out by the fixed bed method in the column filled by the bentonite mixture with a bentonite-to-quartz sand weight percent ratio of 0/100, 25/75, 50/50, 75/25, and 100/0 on the water saturated condition flown by uranyl nitrate solution at concentration (Co of 500 ppm. The concentration of uranium in the effluents in interval 15 minutes represented as Ct was analyzed by spectrophotometer, then using Co and Ct, retardation factor (R and dispersivity ( were determined. The experiment data showed that the bentonite of -60+80 mesh and the quartz sand of -20+40 mesh on bentonite-to-quartz sand with weight percent ratio of 50/50 gave the highest retardation factor and dispersivity of 18.37 and 0.0363 cm, respectively.   Keywords: bentonite, quartz sand, backfill materials, radioactive waste

  5. Reuse of waste foundry sand through interaction with sodium silicate binder

    International Nuclear Information System (INIS)

    Souza, J.C.; Chinelatto, A.S.A.; Chinelatto, A.L.; Oliveira, I.L.

    2012-01-01

    Green sand molds are used in metal casting process. However, after heating, activated bentonite present in green sand lose the binding properties, and part of the foundry sand has to be discarded from the process. The ABNT NBR 15.984/2011 establishes the management of waste foundry sand (WFS) avoiding disposal in landfills. The objective of this work was to investigate the possibility of reusing the WFS from the study of their interaction with sodium silicate binder. Studies with silica sand and new green sand was performed to compare the results obtained with the WFS. The characterizations of the samples were performed by measures the compressive strength, X-ray diffraction, optical microscopy and scanning electron microscopy. The results showed that there is interaction of the sodium silicate with the WFS as well as with the silica sand and green sand. (author)

  6. Study physico-chemical of the sand of the western ERG (Western South Algeria)

    Energy Technology Data Exchange (ETDEWEB)

    Allam, M.; Tafraoui, A. [Faculty of sciences and technology, University of Bechar (Algeria)], email: allammessaouda@yahoo.fr

    2011-07-01

    Silica is gaining increasing importance as it is the base for the production of pure silicon, for which several applications are under development in the electronic and solar energy sectors. The aim of this study is to characterize the sand taken from the Western Erg of Algeria to determine the percentage of silicon it contains. Characterization was done through physical analysis to determine the granulometry of the sand. A chemical analysis was next performed, using diffraction of X-rays and a scanning electron microscope to determine the chemical composition of the sand. Results showed that the sand is mainly made of quartz in the form of rounded and subbarrondis grains and that silicon is prevalent, accounting for 98% of the composition. This study demonstrated that sand from the Western Erg of Algeria is rich in silicon and could be used for silicon production.

  7. Laboratory-scale column study for remediation of TCE-contaminated aquifers using three-section controlled-release potassium permanganate barriers.

    Science.gov (United States)

    Yuan, Baoling; Li, Fei; Chen, Yanmei; Fu, Ming-Lai

    2013-05-01

    A laboratory-scale study with a sand column was designed to simulate trichloroethylene (TCE) pollution in the aquifer environment with three-section controlled-release potassium permanganate (CRP) barriers. The main objective of this study was to evaluate the feasibility of CRP barriers in remediation of TCE in aquifers in a long-term and controlled manner. CRP particles with a 1:3 molar ratio of KMnO4 to stearic acid showed the best controlled-release properties in pure water, and the theoretical release time was 138.5 days. The results of TCE removal in the test column indicated that complete removal efficiency of TCE in a sand column by three-section CRP barriers could be reached within 15 days. The molar ratio of KMnO4 to TCE in the three-section CRP barriers was 16:1, which was much lower than 82:1 as required when KMnO4 solution is used directly to achieve complete destruction of TCE. This result revealed that the efficiency of CRP for remediation of TCE was highly improved after encapsulation.

  8. Three-dimensional fabrication and characterisation of core-shell nano-columns using electron beam patterning of Ge-doped SiO2

    DEFF Research Database (Denmark)

    Gontard, Lionel C.; Jinschek, Joerg R.; Ou, Haiyan

    2012-01-01

    electron tomography. The results show that transformations in insulators that have been subjected to intense irradiation using charged particles can be studied directly in three dimensions. The fabricated structures include core-shell nano-columns, sputtered regions, voids, and clusters. (C) 2012 American......A focused electron beam in a scanning transmission electron microscope (STEM) is used to create arrays of core-shell structures in a specimen of amorphous SiO2 doped with Ge. The same electron microscope is then used to measure the changes that occurred in the specimen in three dimensions using...

  9. Mineral sands

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    This paper presents an outlook of the Australian mineral sand industry and covers the major operators. It is shown that conscious of an environmentally minded public, the Australian miners have led the way in the rehabilitation of mined areas. Moreover the advanced ceramic industry is generating exciting new perspectives for zircon producers and there is a noticeable growth in the electronic market for rare earths, but in long term the success may depend as much on environmental management and communication skills as on mining and processing skills

  10. Experimental Study on Stress Monitoring of Sand-Filled Steel Tube during Impact Using Piezoceramic Smart Aggregates.

    Science.gov (United States)

    Du, Guofeng; Zhang, Juan; Zhang, Jicheng; Song, Gangbing

    2017-08-22

    The filling of thin-walled steel tubes with quartz sand can help to prevent the premature buckling of the steel tube at a low cost. During an impact, the internal stress of the quartz sand-filled steel tube column is subjected to not only axial force but also lateral confining force, resulting in complicated internal stress. A suitable sensor for monitoring the internal stress of such a structure under an impact is important for structural health monitoring. In this paper, piezoceramic Smart Aggregates (SAs) are embedded into a quartz Sand-Filled Steel Tube Column (SFSTC) to monitor the internal structural stress during impacts. The piezoceramic smart aggregates are first calibrated by an impact hammer. Tests are conducted to study the feasibility of monitoring the internal stress of a structure. The results reflect that the calibration value of the piezoceramic smart aggregate sensitivity test is in good agreement with the theoretical value, and the output voltage value of the piezoceramic smart aggregate has a good linear relationship with external forces. Impact tests are conducted on the sand-filled steel tube with embedded piezoceramic smart aggregates. By analyzing the output signal of the piezoceramic smart aggregates, the internal stress state of the structure can be obtained. Experimental results demonstrated that, under the action of impact loads, the piezoceramic smart aggregates monitor the compressive stress at different locations in the steel tube, which verifies the feasibility of using piezoceramic smart aggregate to monitor the internal stress of a structure.

  11. Mobility of nanosized cerium dioxide and polymeric capsules in quartz and loamy sands saturated with model and natural groundwaters.

    Science.gov (United States)

    Petosa, Adamo Riccardo; Ohl, Carolin; Rajput, Faraz; Tufenkji, Nathalie

    2013-10-01

    The environmental and health risks posed by emerging engineered nanoparticles (ENPs) released into aquatic environments are largely dependent on their aggregation, transport, and deposition behavior. Herein, laboratory-scale columns were used to examine the mobility of polyacrylic acid (PAA)-coated cerium dioxide nanoparticles (nCeO2) and an analogous nanosized polymeric capsule (nCAP) in water saturated quartz sand or loamy sand. The influence of solution ionic strength (IS) and cation type (Na(+), Ca(2+), or Mg(2+)) on the transport potential of these ENPs was examined in both granular matrices and results were also compared to measurements obtained using a natural groundwater. ENP suspensions were characterized using dynamic light scattering and nanoparticle tracking analysis to establish aggregate size, and laser Doppler electrophoresis to determine ENP electrophoretic mobility. Regardless of IS, virtually all nCeO2 particles suspended in NaNO3 eluted from the quartz sand-packed columns. In contrast, heightened nCeO2 and nCAP particle retention and dynamic (time-dependent) transport behavior was observed with increasing concentrations of the divalent salts and in the presence of natural groundwater. Enhanced particle retention was also observed in loamy sand in comparison to the quartz sand, emphasizing the need to consider the nature of the aqueous matrix and granular medium in evaluating contamination risks associated with the release of ENPs in natural and engineered aquatic environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Electronic Nose using Gas Chromatography Column and Quartz Crystal Microbalance

    Directory of Open Access Journals (Sweden)

    Hari Agus Sujono

    2011-08-01

    Full Text Available The conventional electronic nose usually consists of an array of dissimilar chemical sensors such as quartz crystal microbalance (QCM combined with pattern recognition algorithm such as Neural network. Because of parallel processing, the system needs a huge number of sensors and circuits which may emerge complexity and inter-channel crosstalk problems. In this research, a new type of odor identification which combines between gas chromatography (GC and electronic nose methods has been developed. The system consists of a GC column and a 10-MHz quartz crystal microbalance sensor producing a unique pattern for an odor in time domain. This method offers advantages of substantially reduced size, interferences and power consumption in comparison to existing odor identification system. Several odors of organic compounds were introduced to evaluate the selectivity of the system. Principle component analysis method was used to visualize the classification of each odor in two-dimensional space. This system could resolve common organic solvents, including molecules of different classes (aromatic from alcohols as well as those within a particular class (methanol from ethanol and also fuels (premium from pertamax. The neural network can be taught to recognize the odors tested in the experiment with identification rate of 85 %. It is therefore the system may take the place of human nose, especially for poisonous odor evaluations.

  13. Reduction of Mn-oxides by ferrous iron in a flow system: column experiment and reactive transport modeling

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Appelo, C. A. J.

    2000-01-01

    Cl2 solution into the column, an ion distribution pattern was observed in the effluent that suggests the formation of separate reaction fronts for Mn(III)-oxide and Mn(IV)-oxide travelling at different velocities through the column. At the proximal reaction front, Fe21 reacts with MnO2 producing Fe......The reduction of Mn-oxide by Fe21 was studied in column experiments, using a column filled with natural Mn-oxide coated sand. Analysis of the Mn-oxide indicated the presence of both Mn(III) and Mn(IV) in the Mn-oxide. The initial exchange capacity of the column was determined by displacement...... of adsorbed Ca21 with Mg21. Subsequently a FeCl2 solution was injected into the column causing the reduction of the Mn-oxide and the precipitation of Fe(OH)3. Finally the exchange capacity of the column containing newly formed Fe(OH)3 was determined by injection of a KBr solution. During injection of the Fe...

  14. Environmental Impacts of Sand Exploitation. Analysis of Sand Market

    Directory of Open Access Journals (Sweden)

    Marius Dan Gavriletea

    2017-06-01

    Full Text Available Sand is an indispensable natural resource for any society. Despite society’s increasing dependence on sand, there are major challenges that this industry needs to deal with: limited sand resources, illegal mining, and environmental impact of sand mining. The purpose of this paper is twofold: to present an overview of the sand market, highlighting the main trends and actors for production, export and import, and to review the main environmental impacts associated with sand exploitation process. Based on these findings, we recommend different measures to be followed to reduce negative impacts. Sand mining should be done in a way that limits environmental damage during exploitation and restores the land after mining operations are completed.

  15. Transport and retention of strontium in surface-modified quartz sand with different wettability

    International Nuclear Information System (INIS)

    Yifei Li; Shuaihui Tian; Tianwei Qian

    2011-01-01

    Instead of radioactive 90 Sr, common strontium chloride was used to simulate the migration of radioactive strontium chloride in surface hydroxylated, silanized, and common quartz sand. The sorption and retardation characteristics of strontium (Sr 2+ ) in these surface modified quartz sands were studied by batch tests and column experiments. The equilibrium sorption data for Sr 2+ on different wettability sands were described by the Langmuir and Freundlich isotherm models, and the Langmuir model has been found to provide better correlation for hydrophilic sand. The breakthrough curves (BTCs) of Sr 2+ in these media were analyzed with the equilibrium convection-dispersion equation (CDE) and a non-equilibrium two-region mobile-immobile model (TRM) using a nonlinear least square curve-fitting program CXTFIT. The TRM model showed better fit to the measured BTCs of Sr 2+ , and the parameters of the fraction of mobile water indicated that significant preferential flow effected the non-equilibrium transport of Sr 2+ . Although TRM model could not fit the Sr 2+ BTCs very well, the parameter estimated by TRM model may be more reliable than those obtained from batch experiments because the transport of Sr 2+ in these kind of sand is non-equilibrium processes. (author)

  16. Dynamics of deposited fly-ash and fine grained magnetite in sandy material of different porosity (column experiments)

    Science.gov (United States)

    Kapicka, Ales; Kodesova, Radka; Petrovsky, Eduard; Grison, Hana

    2010-05-01

    Several studies confirm that soil magnetometry can serve as proxy of industrial immisions as well as heavy-metal contamination. The important assumption for magnetic mapping of contaminated soils is that atmospherically deposited particulate matter, including the ferrimagnetic phase, accumulates in the top soil horizons and remains there over long period. Only if this is true, large areas can be reliably mapped using soil magnetometry, and, moreover, this method can be used also for long-term monitoring. However, in soil types such as sandy soils with different porosity or soils with substantial variability of water regime, translocation of the deposited anthropogenic particles may result in biased (underestimated) values of the measured topsoil magnetic susceptibility. From the physical point of view, this process may be considered as colloid transport through porous medium. In our column experiments in laboratory we used three technical sands with different particle sizes (0,63 - 1.25mm, 0,315-0,80mm, 0,10-0,63mm). Sands in cylinders were contaminated on the surface by fly-ashes from coal-burning power plant (mean grain size 10μm) and fine grained Fe3O4 (grain size < 20 μm). Soil moisture sensors were used to monitor water regime within the sand columns after controlled rain simulation and temperature distribution in sand column was measured as well. Vertical migration of ferrimagnetic particles-tracers presented in the fly-ash was measured by SM 400 Kappameter. By means of magnetic susceptibility distribution we studied two parameters: gradual shift of peak concentration of contaminants (relative to surface layer) and maximum penetration depth. Results indicated that after rain simulation (pulls infiltration of defined water volume) the positions of peak values moved downwards compared to the initial state and gradual decrease of susceptibility peak values were detected in all studied sand formations. Fly-ash migrated more or less freely in coarse sand

  17. Posterior spiracles of fourth instar larvae of four species of phlebotomine sand flies (Diptera: Psychodidae under scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Pessoa Felipe Arley Costa

    2000-01-01

    Full Text Available In the present study, posterior spiracles of laboratory-reared fourth instar larvae of Lutzomyia longipalpis, L. migonei, L. lenti, and L. whitmani (Diptera: Psychodidae of the State of Ceará, Brazil, were examined under scanning electron microscopy. The number of papillae of spiracles examined varied according to the species examined, but no intraspecific differences were found. The importance of this structure to sand fly larva identification and phylogeny is commented.

  18. Experimental Measurement of Diffusive Extinction Depth and Soil Moisture Gradients in Southwestern Saudi Arabian Dune Sand

    KAUST Repository

    Mughal, Iqra

    2013-05-01

    In arid lands, a major contribution to water loss is by soil water evaporation. Desert sand dunes in arid regions are devoid of runoff and have high rates of infiltration. Rainwater is commonly stored within them because of the low permeability soils in the underlying desert pavement. In such cases, moisture is confined in the sand dune below a depth, termed as the “extinction depth”, where it is protected from evaporation during long dry periods. Moreover, desert sand dunes have sparse vegetation, which results in low transpiration losses from the stored water. The water accumulated below the extinction depth of the sand dunes can be utilized for various purposes such as in irrigation to support desert agriculture. In this study, field experiments were conducted in Western Saudi Arabia to monitor the soil moisture gradients and determine the diffusive extinction depth of dune sand. The dune sand was saturated with water and was exposed to natural conditions (evaporation and precipitation). The decline of the water level in the sand column was continuously recorded using transducers and sensors installed at different depths monitored the temporal variation of temperature and moisture content within the sand. The hydrological simulator HYDRUS-1D was used to construct the vertical profiles of soil water content and temperature and the results obtained from HYDRUS-1D were compared to the gradients monitored by the sensors.

  19. Consolidation Theory for a Stone Column Composite Foundation under Multistage Loading

    Directory of Open Access Journals (Sweden)

    Shenggen Huang

    2016-01-01

    Full Text Available The consolidation theories considering instant load cannot fully reveal the consolidation mechanism of a stone column composite foundation used in the expressway embankments due to the time effect of loading; that is, the expressway embankments are often constructed in several stages for a long time. Meanwhile, owing to the special property that the pile-soil stress ratio is larger than 1, the consolidation theory for sand drain well foundation cannot be used directly in the consolidation analysis of stone column composite foundation. Based on the principle that the vertical load applied on the composite foundation is shared by the stone column and the surrounding soil, the governing solutions for the stone column composite foundation under a multistage load are established. By virtue of the separation of variables, the corresponding solutions of degree of consolidation for loading stage and maintaining load stage are derived separately. According to the Carrillo theorem, the solution for the average total degree of consolidation of entire composite foundation is also obtained. Finally, the reasonableness of the present solution has been verified by comparing the consolidation curve calculated by the present solution with that measured by site test.

  20. Design and simulation of a 30 kV, 60 kW electron optical column for melting applications

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Sachin; Kandaswamy, E.; Bapat, A.V., E-mail: saching@barc.gov.in [Bhabha Atomic Research Centre, Mumbai (India)

    2014-07-01

    Electron beam offers unique advantages as a heat source for melting of refractory metals. It provides contamination free homogeneous melting with precise heat control on the melt target. This paper reports the complete electron optics design procedure for a 30 kV, 60 kW melting gun. The design objective of the electron optical column is to obtain the required power density on the target (10{sup 3}-10{sup 4} W/cm{sup 2}) using electrostatic and electromagnetic lenses. The design constrains are to minimize the high voltage discharges in the gun and beam losses in the beam transport. The challenging task of reducing the electrical discharges in the gun during high power melting with the help of twin electromagnetic lenses is presented in the paper. (author)

  1. Consolidation Theory for a Stone Column Composite Foundation under Multistage Loading

    OpenAIRE

    Huang, Shenggen; Feng, Yingtao; Liu, Hao; Wu, Wenbing; Mei, Guoxiong

    2016-01-01

    The consolidation theories considering instant load cannot fully reveal the consolidation mechanism of a stone column composite foundation used in the expressway embankments due to the time effect of loading; that is, the expressway embankments are often constructed in several stages for a long time. Meanwhile, owing to the special property that the pile-soil stress ratio is larger than 1, the consolidation theory for sand drain well foundation cannot be used directly in the consolidation ana...

  2. Ground improvement using soil–cement columns: Experimental investigation

    Directory of Open Access Journals (Sweden)

    Ahmed Farouk

    2013-12-01

    Full Text Available The construction of heavy structures on soils of low relative density is a challenging task. The inclusion of soil–cement columns produced by the deep mixing method is one of the soil stabilizing techniques that could be applied successfully to overcome this challenge. Nevertheless, this technique did not receive a considerable attention in Egypt yet. In the first part of this study, two different natural silty sand soils extracted from the Delta of the River Nile were mixed with cement to prepare samples of different cement doses and different water cement ratios. After curing, the hardened samples were tested and their unconfined compressive strength was investigated. The second part of this study investigates the interaction between a strip footing model and Nile deltaic soil improved by a group of soil–cement columns. Results of the first part of this study showed that the compressive strength of the investigated Nile delta soils could be increased even at lower values of cement doses. Results extracted from the second part of this study showed that a considerable settlement reduction up to 80% could be achieved depending on both the number and the length of the soil–cement columns that is used to improve the soil.

  3. Light and electron microscopy of contacts between primary afferent fibres and neurones with axons ascending the dorsal columns of the feline spinal cord.

    Science.gov (United States)

    Maxwell, D J; Koerber, H R; Bannatyne, B A

    1985-10-01

    In addition to primary afferent fibres, the dorsal columns of the cat spinal cord contain ascending second-order axons which project to the dorsal column nuclei. The aim of the present study was to obtain morphological evidence that certain primary afferent axons form monosynaptic contacts with cells of origin of this postsynaptic dorsal column pathway. In ten adult cats, neurones with axons ascending the dorsal columns were retrogradely labelled with horseradish peroxidase using a pellet implantation method in the thoracic dorsal columns. In the lumbosacral regions of the same animals, primary afferent fibres were labelled intra-axonally with ionophoretic application of horseradish peroxidase. Tissue containing labelled axons was prepared for light and combined light and electron microscopy. Ultrastructural examination demonstrated that slowly adapting (Type I), hair follicle, Pacinian corpuscle and group Ia muscle spindle afferents formed monosynaptic contacts with labelled cells and light microscopical analysis suggested that they also received monosynaptic input from rapidly adapting (Krause) afferents. This evidence suggests that sensory information from large-diameter cutaneous and muscle spindle afferent fibres is conveyed disynaptically via the postsynaptic dorsal column pathway to the dorsal column nuclei. Some of the input to this pathway is probably modified in the spinal cord as the majority of primary afferent boutons forming monosynaptic contacts were postsynaptic to other axon terminals. The postsynaptic dorsal column system appears to constitute a major somatosensory pathway in the cat.

  4. Removal of nitrate, ammonia and phosphate from aqueous solutions in packed bed filter using biochar augmented sand media

    Directory of Open Access Journals (Sweden)

    El Hanandeh Ali

    2017-01-01

    Full Text Available Nutrients from wastewater are a major source of pollution because they can cause significant impact on the ecosystem. Accordingly, it is important that the nutrient concentrations are kept to admissible levels to the receiving environment. Often regulatory limits are set on the maximum allowable concentrations in the effluent. Therefore, wastewater must be treated to meet safe levels of discharge. In this study, laboratory investigation of the efficiency of packed bed filters to remove nitrate, ammonium and phosphate from aqueous solutions were conducted. Sand and sand augmented with hydrochloric acid treated biochar (SBC were used as packing media. Synthetic wastewater solution was prepared with PO43−, NO3−, NH4+ concentrations 20, 10, 50 mg/L, respectively. Each experiment ran for a period of five days; samples from the effluent were collected on alternate days. All experiments were duplicated. Over the experiment period, the average removal efficiency of PO43−, NO3−, NH4+ were 99.2%, 72.9%, 96.7% in the sand packed columns and 99.2%, 82.3%, 97.4% in the SBC packed columns, respectively. Although, the presence of biochar in the packing media had little effect on phosphate and ammonium removal, it significantly improved nitrate removal.

  5. Sand transportation and reverse patterns over leeward face of sand dune

    Science.gov (United States)

    Jiang, Hong; Dun, Hongchao; Tong, Ding; Huang, Ning

    2017-04-01

    Sand saltation has complex interactions with turbulent flow and dune form. Most models of wind-blown sand consider ideal circumstances such as steady wind velocity and a flat surface, and the bulk of data on wind flow and sand transport over an individual dune has focused mostly on the influence of dune shape or inter-dune space on the wind flow, neglecting the effect of morphology on sand saltation, particularly airflow and sand transportation over the leeward slope. Wind flow structures over the leeward slope of sand dunes have a fundamental influence on the organization of sand dunes. In order to understand sand dune dynamics, lee face airflow and sediment transportation should be paid more attention. Previous field observations could not measure turbulent flow structure well because of the limited observation points and the influence of experiment structure on wind field. In addition, the reverse sand particles over leeward face could not be collected by sand trap in field. Numerous field observations could not measure turbulent flow structure because of the limited observation points and the influence of experimental structures on the wind field. In addition, the reverse transport of sand particles over leeward face could not be collected by sand traps in field. Therefore, this paper aims to investigate the turbulent flow structure and sand transport pattern over the leeward slope. A numerical model of sand saltation over slope terrain is constructed, which also considers the coupling effects between air flow and sand particles. The large eddy simulation method is used to model turbulent flow. Sand transport is simulated by tracking the trajectory of each sand particle. The results show that terrain significantly alters the turbulent air flow structure and wind-blown sand movement, especially over the leeward slope. Here, mass flux increases initially and then decreases with height in the reversed flow region in the direction of wind flow, and the mass flux

  6. Column bioleaching of arsenic and Heavy metals from gold mine tailings by aspergillus fumigatus

    International Nuclear Information System (INIS)

    Seh-Bardan, Bahi Jalili; Othman, Radziah; Ab Wahid, Samsuri; Husin, Aminudin; Sadegh-Zadeh, Fardin

    2012-01-01

    A column bioleaching experiment was carried out to compare the effectiveness of the fungus Aspergillus fumigatus to bioleach arsenic (As) and heavy metals from the tailings using two different methods. In the first method, which is named as distribution method (DM), the fungus was distributed in the column by means of vertical and horizontal layers of coarse sand. In the other method, named as surface applied method (SAM), the fungus was cultivated on the surface of the tailings, which was covered with a few centimeters of coarse sand. Results showed that in the DM, oxalic acid production was stimulated and maximum removal of As, Fe, Mn, and Zn was 53, 51, 81, and 62%, respectively. However, Pb removal was low (8%), which might be due to the precipitation of Pb as its oxalates. On the other hand, the maximum removal of As, Fe, Mn, Pb, and Zn were 22, 28, 37, 64, and 34%, respectively, for the SAM. Results of the sequential extraction study showed that the DM was effective in removing the water soluble, exchangeable, carbonate, and Fe/Mn oxide fractions of As, Fe, Mn, and Zn. Our study suggested that A. fumigatus has a potential to be used in remediation of heavy metal contaminated sites. Distributing the fungus throughout the entire tailings columns improved the bioleaching of heavy metals by the fungus. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Column bioleaching of arsenic and Heavy metals from gold mine tailings by aspergillus fumigatus

    Energy Technology Data Exchange (ETDEWEB)

    Seh-Bardan, Bahi Jalili; Othman, Radziah; Ab Wahid, Samsuri; Husin, Aminudin; Sadegh-Zadeh, Fardin [Faculty of Agriculture, Department of Land Management, Universiti Putra Malaysia, Serdang, Selangor (Malaysia)

    2012-06-15

    A column bioleaching experiment was carried out to compare the effectiveness of the fungus Aspergillus fumigatus to bioleach arsenic (As) and heavy metals from the tailings using two different methods. In the first method, which is named as distribution method (DM), the fungus was distributed in the column by means of vertical and horizontal layers of coarse sand. In the other method, named as surface applied method (SAM), the fungus was cultivated on the surface of the tailings, which was covered with a few centimeters of coarse sand. Results showed that in the DM, oxalic acid production was stimulated and maximum removal of As, Fe, Mn, and Zn was 53, 51, 81, and 62%, respectively. However, Pb removal was low (8%), which might be due to the precipitation of Pb as its oxalates. On the other hand, the maximum removal of As, Fe, Mn, Pb, and Zn were 22, 28, 37, 64, and 34%, respectively, for the SAM. Results of the sequential extraction study showed that the DM was effective in removing the water soluble, exchangeable, carbonate, and Fe/Mn oxide fractions of As, Fe, Mn, and Zn. Our study suggested that A. fumigatus has a potential to be used in remediation of heavy metal contaminated sites. Distributing the fungus throughout the entire tailings columns improved the bioleaching of heavy metals by the fungus. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Study on the Permeability Characteristics of Polyurethane Soil Stabilizer Reinforced Sand

    Directory of Open Access Journals (Sweden)

    Jin Liu

    2017-01-01

    Full Text Available A polymer material of polyurethane soil stabilizer (PSS is used to reinforce the sand. To understand the permeability characteristics of PSS reinforced sand, a series of reinforcement layer form test, single-hole permeability test, and porous permeability test of sand reinforced with PSS have been performed. Reinforcement mechanism is discussed with scanning electron microscope images. The results indicated that the permeability resistance of sand reinforced with polyurethane soil stabilizer is improved through the formation of reinforcement layer on the sand surface. The thickness and complete degree of the reinforcement layer increase with the increasing of curing time and PSS concentration. The water flow rate decreases with the increasing of curing time or PSS concentration. The permeability coefficient decreases with the increasing of curing time and PSS concentration and increases with the increasing of depth in specimen. PSS fills up the voids of sand and adsorbs on the surface of sand particle to reduce or block the flowing channels of water to improve the permeability resistance of sand. The results can be applied as the reference for chemical reinforcement sandy soil engineering, especially for surface protection of embankment, slope, and landfill.

  9. Gravity flow and solute dispersion in variably saturated sand

    Science.gov (United States)

    Kumahor, Samuel K.; de Rooij, Gerrit H.; Vogel, Hans-Joerg

    2014-05-01

    Solute dispersion in porous media depends on the structure of the velocity field at the pore scale. Hence, dispersion is expected to change with water content and with mean flow velocity. We performed laboratory experiments using a column of repacked fine-grained quartz sand (0.1-0.3 mm grain size) with a porous plate at the bottom to controle the water potential at the lower boundary. We established gravity flow conditions - i.e. constant matric potential and water content throughout the column - for a number of different irrigation rates. We measured breakthrough curves during unit gradient flow for an inert tracer which could be described by the convection-dispersion equation. As the soil water content decreased we observed an initially gradual increase in dispersivity followed by an abrupt increase below a threshold water content (0.19) and pressure head (-38 hPa). This phenomena can be explained by the geometry of phase distribution which was simulated based on Xray-CT images of the porous structure.

  10. Facilitated transport of Cu with hydroxyapatite nanoparticles in saturated sand: Effects of solution ionic strength and composition

    Science.gov (United States)

    Column experiments were conducted to investigate the facilitated transport of Cu in association with hydroxyapatite nanoparticles (nHAP) in water-saturated quartz sand at different solution concentrations of NaCl (0 to 100 mM) or CaCl2 (0.1 to 1.0 mM). The experimental breakthrough curves and retent...

  11. Kinetics of plasma membrane electron transport in a pulmonary endothelial cell-column.

    Science.gov (United States)

    Olson, L E; Merker, M P; Bongard, R D; Brantmeier, B M; Audi, S H; Linehan, J H; Dawson, C A

    1998-01-01

    Thiazine dyes such as toluidine blue O (TBO) are reduced at the luminal endothelial surface. The purpose of this study was to determine the rate of this reaction in endothelial cells in culture. A multiple indicator dilution method was used to measure the reaction kinetics during transient passage of a TBO-containing bolus through a chromatographic column filled with bovine pulmonary arterial endothelial cells grown on microcarrier beads (cell-column). A bolus containing TBO and an inert extracellular reference indicator (FITC-Dextran) was injected upstream of the cell-column, and the indicator concentrations were measured downstream using on-line photodetection. The effects of column flow rate, PO2, and TBO concentration were studied. The fraction of TBO reduced upon passage through the cell-column decreased with increasing flow indicating that the reaction rate rather than TBO delivery controlled TBO reduction. The fraction of TBO reduced did not change with PO2 or dose in the ranges studied. TBO reduction was about 10 times that for steady state TBO sequestration by these cells which, along with the lack of a PO2 effect indicates that the rapid rate of reduction is not the rate-limiting step in steady state sequestration.

  12. Column-to-column packing variation of disposable pre-packed columns for protein chromatography.

    Science.gov (United States)

    Schweiger, Susanne; Hinterberger, Stephan; Jungbauer, Alois

    2017-12-08

    In the biopharmaceutical industry, pre-packed columns are the standard for process development, but they must be qualified before use in experimental studies to confirm the required performance of the packed bed. Column qualification is commonly done by pulse response experiments and depends highly on the experimental testing conditions. Additionally, the peak analysis method, the variation in the 3D packing structure of the bed, and the measurement precision of the workstation influence the outcome of qualification runs. While a full body of literature on these factors is available for HPLC columns, no comparable studies exist for preparative columns for protein chromatography. We quantified the influence of these parameters for commercially available pre-packed and self-packed columns of disposable and non-disposable design. Pulse response experiments were performed on 105 preparative chromatography columns with volumes of 0.2-20ml. The analyte acetone was studied at six different superficial velocities (30, 60, 100, 150, 250 and 500cm/h). The column-to-column packing variation between disposable pre-packed columns of different diameter-length combinations varied by 10-15%, which was acceptable for the intended use. The column-to-column variation cannot be explained by the packing density, but is interpreted as a difference in particle arrangement in the column. Since it was possible to determine differences in the column-to-column performance, we concluded that the columns were well-packed. The measurement precision of the chromatography workstation was independent of the column volume and was in a range of±0.01ml for the first peak moment and±0.007 ml 2 for the second moment. The measurement precision must be considered for small columns in the range of 2ml or less. The efficiency of disposable pre-packed columns was equal or better than that of self-packed columns. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  13. The use of laboratory sand, soil and crushed-glass filter columns for polishing domestic-strength synthetic wastewater that has undergone secondary treatment.

    Science.gov (United States)

    Healy, M G; Burke, P; Rodgers, M

    2010-10-01

    The aim of this study was to examine the performance of intermittently loaded, 150 mm-diameter stratified filter columns of 2 depths (0.65 and 0.375 m) comprising different media--sand, crushed glass and soil--in polishing the effluent from a laboratory horizontal flow biofilm reactor (HFBR) treating synthetic domestic-strength wastewater. The HFBR has been successfully used to remove organic carbon and ammonium-nitrogen (NH4-N) from domestic wastewater. In this treatment method, wastewater is allowed to flow over and back along a stack of polyvinyl chloride (PVC) sheets. Biofilms on the sheets reduce organic carbon, suspended matter, and nutrients in the wastewater, but to achieve the quality of a septic tank system, additional treatment is required. In all filters, at a hydraulic loading rate of 100 L m(-2) d(-1), 40-65% of chemical oxygen demand (COD) and practically 100% of total suspended solids (TSS) were removed, nitrification was complete, and bacterial numbers were reduced by over 80%, with best removals achieved in the soil filters (93%). Soil polishing filters with the depth of 0.65 m performed best in terms of organic carbon, total nitrogen (Tot-N) and bacterial removal. Data from this preliminary study are useful in the design of treatment systems to polish secondary wastewaters with similar water quality characteristics.

  14. Scales and structures in bubbly flows. Experimental analysis of the flow in bubble columns and in bubbling fluidized beds

    NARCIS (Netherlands)

    Groen, J.S.

    2004-01-01

    In this project a detailed experimental analysis was performed of the dynamic flow field in bubbly flows, with the purpose of determining local hydrodynamics and scale effects. Measurements were done in gas-liquid systems (air-water bubble columns) and in gas-solid systems (air-sand bubbing

  15. Copper deficiency can limit nitrification in biological rapid sand filters for drinking water production

    DEFF Research Database (Denmark)

    Wagner, Florian Benedikt; Nielsen, Peter Borch; Boe-Hansen, Rasmus

    2016-01-01

    Incomplete nitrification in biological filters during drinking water treatment is problematic, as it compromises drinking water quality. Nitrification problems can be caused by a lack of nutrients for the nitrifying microorganisms. Since copper is an important element in one of the essential...... enzymes in nitrification, we investigated the effect of copper dosing on nitrification in different biological rapid sand filters treating groundwater. A lab-scale column assay with filter material from a water works demonstrated that addition of a trace metal mixture, including copper, increased ammonium...... to the bulk phase. Overall, copper dosing to poorly performing biological rapid sand filters increased ammonium removal rates significantly, achieving effluent concentrations of below 0.01 mg NH4-N L-1, and had a long-term effect on nitrification performance....

  16. Reclaimability of the spent sand mixture – sand with bentonite – sand with furfuryl resin

    Directory of Open Access Journals (Sweden)

    J. Dańko

    2011-04-01

    Full Text Available Introduction of new binding materials and new technologies of their hardening in casting moulds and cores production requires theapplication of reclamation methods adequate to their properties as well as special devices realizing tasks. The spent sands circulationsystem containing the same kind of moulding and core sands is optimal from the point of view of the expected reclamation results.However, in the face of a significant variability of applied technologies and related to them various reclamation methods, the need - of theobtained reclamation products assessment on the grounds of systematic criteria and uniform bases – arises, with a tendency of indicatingwhich criteria are the most important for the given sand system. The reclaimability results of the mixture of the spent moulding sand withGeko S bentonite and the spent core sand with the Kaltharz 404U resin hardened by acidic hardener 100 T3, are presented in the paper.Investigations were performed with regard to the estimation of an influence of core sands additions (10 –25% on the reclaimed materialquality. Dusts and clay content in the reclaim, its chemical reaction (pH and ignition loss were estimated. The verification of the reclaiminstrumental assessment was performed on the basis of the technological properties estimation of moulding sand with bentonite, where the reclaimed material was used as a matrix.

  17. Analysis of packing microstructure and wall effects in a narrow-bore ultrahigh pressure liquid chromatography column using focused ion-beam scanning electron microscopy.

    Science.gov (United States)

    Reising, Arved E; Schlabach, Sabine; Baranau, Vasili; Stoeckel, Daniela; Tallarek, Ulrich

    2017-09-01

    Column wall effects are well recognized as major limiting factor in achieving high separation efficiency in HPLC. This is especially important for modern analytical columns packed with small particles, where wall effects dominate the band broadening. Detailed knowledge about the packing microstructure of packed analytical columns has so far not been acquired. Here, we present the first three-dimensional reconstruction protocol for these columns utilizing focused ion-beam scanning electron microscopy (FIB-SEM) on a commercial 2.1mm inner diameter×50mm length narrow-bore analytical column packed with 1.7μm bridged-ethyl hybrid silica particles. Two sections from the packed bed are chosen for reconstruction by FIB-SEM: one from the bulk packing region of the column and one from its critical wall region. This allows quantification of structural differences between the wall region and the center of the bed due to effects induced by the hard, confining column wall. Consequences of these effects on local flow velocity in the column are analyzed with flow simulations utilizing the lattice-Boltzmann method. The reconstructions of the bed structures reveal significant structural differences in the wall region (extending radially over approximately 62 particle diameters) compared to the center of the column. It includes the local reduction of the external porosity by up to 10% and an increase of the mean particle diameter by up to 3%, resulting in a decrease of the local flow velocity by up to 23%. In addition, four (more ordered) layers of particles in the direct vicinity of the column wall induce local velocity fluctuations by up to a factor of three regarding the involved velocity amplitudes. These observations highlight the impact of radial variations in packing microstructure on band migration and column performance. This knowledge on morphological peculiarities of column wall effects helps guiding us towards further optimization of the packing process for analytical

  18. Column-by-column compositional mapping by Z-contrast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Molina, S.I. [Departamento de Ciencia de los Materiales e I.M. y Q.I., Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, s/n, 11510 Puerto Real, Cadiz (Spain)], E-mail: sergio.molina@uca.es; Sales, D.L. [Departamento de Ciencia de los Materiales e I.M. y Q.I., Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, s/n, 11510 Puerto Real, Cadiz (Spain); Galindo, P.L. [Departamento de Lenguajes y Sistemas Informaticos, CASEM, Universidad de Cadiz, Campus Rio San Pedro, s/n, 11510 Puerto Real, Cadiz (Spain); Fuster, D.; Gonzalez, Y.; Alen, B.; Gonzalez, L. [Instituto de Microelectronica de Madrid (CNM, CSIC), Isaac Newton 8, 28760 Tres Cantos, Madrid (Spain); Varela, M.; Pennycook, S.J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2009-01-15

    A phenomenological method is developed to determine the composition of materials, with atomic column resolution, by analysis of integrated intensities of aberration-corrected Z-contrast scanning transmission electron microscopy images. The method is exemplified for InAs{sub x}P{sub 1-x} alloys using epitaxial thin films with calibrated compositions as standards. Using this approach we have determined the composition of the two-dimensional wetting layer formed between self-assembled InAs quantum wires on InP(0 0 1) substrates.

  19. Novel field emission SEM column with beam deceleration technology

    International Nuclear Information System (INIS)

    Jiruše, Jaroslav; Havelka, Miloslav; Lopour, Filip

    2014-01-01

    A novel field-emission SEM column has been developed that features Beam Deceleration Mode, high-probe current and ultra-fast scanning. New detection system in the column is introduced to detect true secondary electron signal. The resolution power at low energy was doubled for conventional SEM optics and moderately improved for immersion optics. Application examples at low landing energies include change of contrast, imaging of non-conductive samples and thin layers. - Highlights: • A novel field-emission SEM column has been developed. • Implemented beam deceleration improves the SEM resolution at 1 keV two times. • New column maintains high analytical potential and wide field of view. • Detectors integrated in the column allow gaining true SE and BE signal separately. • Performance of the column is demonstrated on low energy applications

  20. Novel field emission SEM column with beam deceleration technology

    Energy Technology Data Exchange (ETDEWEB)

    Jiruše, Jaroslav; Havelka, Miloslav; Lopour, Filip

    2014-11-15

    A novel field-emission SEM column has been developed that features Beam Deceleration Mode, high-probe current and ultra-fast scanning. New detection system in the column is introduced to detect true secondary electron signal. The resolution power at low energy was doubled for conventional SEM optics and moderately improved for immersion optics. Application examples at low landing energies include change of contrast, imaging of non-conductive samples and thin layers. - Highlights: • A novel field-emission SEM column has been developed. • Implemented beam deceleration improves the SEM resolution at 1 keV two times. • New column maintains high analytical potential and wide field of view. • Detectors integrated in the column allow gaining true SE and BE signal separately. • Performance of the column is demonstrated on low energy applications.

  1. Predictive hydrogeochemical modelling of bauxite residue sand in field conditions.

    Science.gov (United States)

    Wissmeier, Laurin; Barry, David A; Phillips, Ian R

    2011-07-15

    The suitability of residue sand (the coarse fraction remaining from Bayer's process of bauxite refining) for constructing the surface cover of closed bauxite residue storage areas was investigated. Specifically, its properties as a medium for plant growth are of interest to ensure residue sand can support a sustainable ecosystem following site closure. The geochemical evolution of the residue sand under field conditions, its plant nutrient status and soil moisture retention were studied by integrated modelling of geochemical and hydrological processes. For the parameterization of mineral reactions, amounts and reaction kinetics of the mineral phases natron, calcite, tricalcium aluminate, sodalite, muscovite and analcime were derived from measured acid neutralization curves. The effective exchange capacity for ion adsorption was measured using three independent exchange methods. The geochemical model, which accounts for mineral reactions, cation exchange and activity corrected solution speciation, was formulated in the geochemical modelling framework PHREEQC, and partially validated in a saturated-flow column experiment. For the integration of variably saturated flow with multi-component solute transport in heterogeneous 2D domains, a coupling of PHREEQC with the multi-purpose finite-element solver COMSOL was established. The integrated hydrogeochemical model was applied to predict water availability and quality in a vertical flow lysimeter and a cover design for a storage facility using measured time series of rainfall and evaporation from southwest Western Australia. In both scenarios the sand was fertigated and gypsum-amended. Results show poor long-term retention of fertilizer ions and buffering of the pH around 10 for more than 5 y of leaching. It was concluded that fertigation, gypsum amendment and rainfall leaching alone were insufficient to render the geochemical conditions of residue sand suitable for optimal plant growth within the given timeframe. The

  2. Eastern Scheldt Sand, Baskarp Sand No. 15

    DEFF Research Database (Denmark)

    Andersen, A. T; Madsen, E. B.; Schaarup-Jensen, A. L.

    The present data report contains data from 13 drained triaxial tests, performed on two different sand types in the Soil Mechanics Laboratory at Aalborg University in March, 1997. Two tests have been performed on Baskarp Sand No. 15, which has already ken extensively tested in the Soil Mechanics...... Laboratory. The remaining 11 triaxial tests have ben performed on Eastern Scheldt Sand, which is a material not yet investigated at the Soil Mechanics Laboratory. In the first pari of this data report, the characteristics of the two sand types in question will be presented. Next, a description...... will described. In this connection, the procedure for preparation of the soil specimens will be presented, and the actual performance of the tests will be briefly outlined. Finally, the procedure for processing of the measurements from the laboratory in order to obtain usable data will be described. The final...

  3. Micro-Columnated Loop Heat Pipe: The Future of Electronic Substrates

    Science.gov (United States)

    Dhillon, Navdeep Singh

    The modern world is run by semiconductor-based electronic systems. Due to continuous improvements in semiconductor device fabrication, there is a clear trend in the market towards the development of electronic devices and components that not only deliver enhanced computing power, but are also more compact. Thermal management has emerged as the primary challenge in this scenario where heat flux dissipation of electronic chips is increasing exponentially, but conventional cooling solutions such as conduction and convection are no longer feasible. To keep device junction temperatures within the safe operating limit, there is an urgent requirement for ultra-high-conductivity thermal substrates that not only absorb and transport large heat fluxes, but can also provide localized cooling to thermal hotspots. This dissertation describes the design, modeling, and fabrication of a phase change-based, planar, ultra-thin, passive thermal transport system that is inspired by the concept of loop heat pipes and capillary pumped loops. Fabricated on silicon and Pyrex wafers using microfabrication techniques, the micro-columnated loop heat pipe (muCLHP) can be integrated directly with densely packed or multiply-stacked electronic substrates, to provide localized high-heat-flux thermal management. The muCLHP employs a dual-scale coherent porous silicon(CPS)-based micro-columnated wicking structure, where the primary CPS wick provides large capillary forces for fluid transport, while a secondary surface-wick maximizes the rate of thin-film evaporation. To overcome the wick thickness limitation encountered in conventional loop heat pipes, strategies based on MEMS surface micromachining techniques were developed to reduce parasitic heat flow from the evaporator to the compensation chamber of the device. Finite element analysis was used to confirm this reduction in a planar evaporator design, thus enabling the generation of a large motive temperature head for continuous device operation

  4. Effect of concentration gradients on biodegradation in bench-scale sand columns with HYDRUS modeling of hydrocarbon transport and degradation.

    Science.gov (United States)

    Horel, Agota; Schiewer, Silke; Misra, Debasmita

    2015-09-01

    The present research investigated to what extent results obtained in small microcosm experiments can be extrapolated to larger settings with non-uniform concentrations. Microbial hydrocarbon degradation in sandy sediments was compared for column experiments versus homogenized microcosms with varying concentrations of diesel, Syntroleum, and fish biodiesel as contaminants. Syntroleum and fish biodiesel had higher degradation rates than diesel fuel. Microcosms showed significantly higher overall hydrocarbon mineralization percentages (p transport and degradation of the investigated fuels in vadose zone conditions similar to those in laboratory column experiments. The numerical model was used to evaluate the impact of different degradation rate constants from microcosm versus column experiments.

  5. How do peat type, sand addition and soil moisture influence the soil organic matter mineralization in anthropogenically disturbed organic soils?

    Science.gov (United States)

    Säurich, Annelie; Tiemeyer, Bärbel; Don, Axel; Burkart, Stefan

    2017-04-01

    Drained peatlands are hotspots of carbon dioxide (CO2) emissions from agriculture. As a consequence of both drainage induced mineralization and anthropogenic sand mixing, large areas of former peatlands under agricultural use contain soil organic carbon (SOC) at the boundary between mineral and organic soils. Studies on SOC dynamics of such "low carbon organic soils" are rare as the focus of previous studies was mainly either on mineral soils or "true" peat soil. However, the variability of CO2 emissions increases with disturbance and therefore, we have yet to understand the reasons behind the relatively high CO2 emissions of these soils. Peat properties, soil organic matter (SOM) quality and water content are obviously influencing the rate of CO2 emissions, but a systematic evaluation of the hydrological and biogeochemical drivers for mineralization of disturbed peatlands is missing. With this incubation experiment, we aim at assessing the drivers of the high variability of CO2 emissions from strongly anthropogenically disturbed organic soil by systematically comparing strongly degraded peat with and without addition of sand under different moisture conditions and for different peat types. The selection of samples was based on results of a previous incubation study, using disturbed samples from the German Agricultural Soil Inventory. We sampled undisturbed soil columns from topsoil and subsoil (three replicates of each) of ten peatland sites all used as grassland. Peat types comprise six fens (sedge, Phragmites and wood peat) and four bogs (Sphagnum peat). All sites have an intact peat horizon that is permanently below groundwater level and a strongly disturbed topsoil horizon. Three of the fen and two of the bog sites have a topsoil horizon altered by sand-mixing. In addition the soil profile was mapped and samples for the determination of soil hydraulic properties were collected. All 64 soil columns (including four additional reference samples) will be installed

  6. Study of transport in unsaturated sands using radioactive tracers

    International Nuclear Information System (INIS)

    Merritt, W.F.; Pickens, J.F.; Allison, G.B.

    1979-01-01

    A laboratory experiment was conducted to investigate the mixing that occurs as a series of labelled pulses of water are transported by gravity drainage down through a sand filled column having a water table imposed at the bottom. It also demonstrated the utility of gamma-ray emitting radioactive tracers in studying transport in unsaturated or saturated porous media. The motivation for pursuing this topic was developed from observing that the content of oxygen-18, deuterium and tritium in rainwater shows marked temporal variations whereas their concentrations below the water table in shallow ground water flow systems are generally found to show much less variation. (auth)

  7. Copper (II) Removal In Anaerobic Continuous Column Reactor System By Using Sulfate Reducing Bacteria

    Science.gov (United States)

    Bilgin, A.; Jaffe, P. R.

    2017-12-01

    Copper is an essential element for the synthesis of the number of electrons carrying proteins and the enzymes. However, it has a high level of toxicity. In this study; it is aimed to treat copper heavy metal in anaerobic environment by using anaerobic continuous column reactor. Sulfate reducing bacteria culture was obtained in anaerobic medium using enrichment culture method. The column reactor experiments were carried out with bacterial culture obtained from soil by culture enrichment method. The system is operated with continuous feeding and as parallel. In the first rector, only sand was used as packing material. The first column reactor was only fed with the bacteria nutrient media. The same solution was passed through the second reactor, and copper solution removal was investigated by continuously feeding 15-600 mg/L of copper solution at the feeding inlet in the second reactor. When the experiment was carried out by adding the 10 mg/L of initial copper concentration, copper removal in the rate of 45-75% was obtained. In order to determine the use of carbon source during copper removal of mixed bacterial cultures in anaerobic conditions, total organic carbon TOC analysis was used to calculate the change in carbon content, and it was calculated to be between 28% and 75%. When the amount of sulphate is examined, it was observed that it changed between 28-46%. During the copper removal, the amounts of sulphate and carbon moles were equalized and more sulfate was added by changing the nutrient media in order to determine the consumption of sulphate or carbon. Accordingly, when the concentration of added sulphate is increased, it is calculated that between 35-57% of sulphate is spent. In this system, copper concentration of up to 15-600 mg / L were studied.

  8. Acid rock drainage passive remediation using alkaline clay and impacts of vegetation and saturated sand barrier

    Science.gov (United States)

    Plaza, F.; Wen, Y.; Liang, X.

    2017-12-01

    Acid rock drainage (ARD) caused by abundance of coal refuse (CR) deposits in mining regions requires adequate treatment to prevent serious water pollution due to its acidity and high concentrations of sulfate and metals/metalloids. Over the past decades, various approaches have been explored and developed to remediate ARD. This study uses laboratory experiments to investigate the effectiveness and impacts of ARD passive remediation using alkaline clay (AC), a by-product of the aluminum refining process. Twelve column kinetic leaching experiments were set up with CR/AC mixing ratios ranging from 1%AC to 10%AC. Samples were collected from these columns to measure the pH, sulfate, metals/metalloids, acidity and alkalinity. Additional tests of XRD and acid base accounting were also conducted to better characterize the mineral phase in terms of the alkalinity and acidity potential. Based on the leachate measurement results, these columns were further classified into two groups of neutral/near neutral pH and acidic pH for further analysis. In addition, impacts of the vegetation and saturated sand layer on the remediation effectiveness were explored. The results of our long-term (more than three years in some cases) laboratory experiments show that AC is an effective ARD remediation material for the neutralization of leachate pH and immobilization of sulfate and metals such as Fe, Mn, Cu, Zn, Ni, Pb, Cd, Co. The CR/AC mixing ratios higher than 3%AC are found to be effective, with 10% close to optimal. Moreover, the results demonstrate the benefits of using vegetation and a saturated sand barrier. Vegetation acted as a phytoaccumulation/phytoextraction agent, causing an additional immobilization of metals. The saturated sand barrier blocked the oxygen and water diffusion downwards, leading to a reduction of the pyrite oxidation rate. Finally, the proposed remediation approach shows that the acidity consumption will likely occur before all the alkalinity is exhausted

  9. Submarine sand ridges and sand waves in the eastern part of the China Sea

    Science.gov (United States)

    Wu, Ziyin; Li, Shoujun; Shang, Jihong; Zhou, Jieqiong; Zhao, Dineng; Liang, Yuyang

    2016-04-01

    Integrated with multi-beam and single-beam echo sounding data, as well as historical bathymetric data, submarine bathymetric maps of the eastern part of the China Sea, including the Bohai Sea, Huanghai Sea, and East China Sea, are constructed to systematically study submarine sand ridges and sand waves in the eastern part of the China Sea, combined with high-resolution seismic, sub-bottom profile and borehole data. Submarine sand ridges are extraordinarily developed in the eastern part of the China Sea, and 7 sand ridge areas can be divided from north to south, that is, the Laotieshan Channel sand ridge area in the Bohai Sea, the Korea Bay sand ridge area in the southern Huanghai Sea, the sand ridge area in the eastern Huanghai islands and the Huanghai Troughs, the Jianggang sand ridge area in the western Huanghai Sea, the sand ridge area in the East China Sea shelf, and the sand ridge and sand wave area in the Taiwan Strait and Taiwan Banks. The distribution area of the sand ridges and sand waves covers more than 450,000 km2, wherein ~10,000 km2 in the Bohai Bay, ~200,000 km2 in the Huanghai Sea, ~200,000 km2 in the East China Sea shelf, and ~40,000 km2 in the Taiwan Strait and Taiwan Banks, respectively. The great mass of sand ridges are distributed within water depth of 5-160 m, with a total length of over 160 km and a main width of 5-10 km. The inner structure of the sand ridges presents features of high-angle inclined beddings, with main lithology of sands, sand-mud alternations partly visible, and a small number of mud cores. Dating results indicate that the sand ridges in the eastern part of the China Sea are mainly developed in the Holocene. Sea-level variation dominates the sand ridge evolution in the eastern part of the China Sea since the LGM, and the sand ridges developed in the area of < 60m water depth are appeared in bad activity, meanwhile sand ridges with good activity are still developed in large scale.

  10. Aluminum-based water treatment residual use in a constructed wetland for capturing urban runoff phosphorus: Column study

    Science.gov (United States)

    Aluminum-based water treatment residuals (Al-WTR) have a strong affinity to sorb phosphorus. In a proof-of-concept greenhouse column study, Al-WTR was surface-applied at 0, 62, 124, and 248 Mg/ha to 15 cm of soil on top of 46 cm of sand; Al-WTR rates were estimated to capture 0, 10, 20, and 40 year...

  11. Simultaneous attenuation of pharmaceuticals, organic matter, and nutrients in wastewater effluent through managed aquifer recharge: Batch and column studies.

    Science.gov (United States)

    Im, Huncheol; Yeo, Inseol; Maeng, Sung Kyu; Park, Chul Hwi; Choi, Heechul

    2016-01-01

    Batch and column experiments were conducted to evaluate the removal of organic matter, nutrients, and pharmaceuticals and to identify the removal mechanisms of the target contaminants. The sands used in the experiments were obtained from the Youngsan River located in South Korea. Neutral and cationic pharmaceuticals (iopromide, estrone, and trimethoprim) were removed with efficiencies greater than 80% from different sand media during experiments, due to the effect of sorption between sand and pharmaceuticals. However, the anionic pharmaceuticals (sulfamethoxazole, ketoprofen, ibuprofen, and diclofenac) were more effectively removed by natural sand, compared to baked sand. These observations were mainly attributed to biodegradation under natural conditions of surface organic matter and ATP concentrations. The removal of organic matter and nitrogen was also found to increase under biotic conditions. Therefore, it is indicated that biodegradation plays an important role and act as major mechanisms for the removal of organic matter, nutrients, and selected pharmaceuticals during sand passage and the managed aquifer recharge, which is an effective treatment method for removing target contaminants. However, the low removal efficiencies of pharmaceuticals (e.g., carbamazepine and sulfamethoxazole) require additional processes (e.g., AOPs, NF and RO membrane), a long residence time, and long travel distance for increasing the removal efficiencies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Electric field strength in a silicon surface barrier detector with the presence of a dielectric plasma column

    International Nuclear Information System (INIS)

    Kanno, Ikuo

    1994-01-01

    The dynamic change of the electric field strength in a silicon surface barrier detector (SSBD) is studied. With the presence of a dielectric plasma column in the depletion layer of the SSBD, the electric field strength inside/outside the plasma column is suppressed/enhanced. As the length and the dielectric constant of the plasma column become shorter and smaller, the suppression and enhancement of the electric field strength become less. The electric field strength recovers the initial state, when the plasma column disappears. When the electrons and holes are inside/outside the dielectric plasma column, they have less/more electric potential than the one they have when there is no plasma column. During the movement of the electron/hole outside the plasma column to the positive/negative electrode, the enhanced electric field strength becomes smaller. Electron and hole pairs, which are the parts of the dielectric plasma column, arrive at positive and negative electrodes, having insufficient electric potential to induce the unit charge. This paper shows that the presence of a dielectric plasma column explains the main part of the residual defect in a SSBD. ((orig.))

  13. Aspartic acid incorporated monolithic columns for affinity glycoprotein purification.

    Science.gov (United States)

    Armutcu, Canan; Bereli, Nilay; Bayram, Engin; Uzun, Lokman; Say, Rıdvan; Denizli, Adil

    2014-02-01

    Novel aspartic acid incorporated monolithic columns were prepared to efficiently affinity purify immunoglobulin G (IgG) from human plasma. The monolithic columns were synthesised in a stainless steel HPLC column (20 cm × 5 mm id) by in situ bulk polymerisation of N-methacryloyl-L-aspartic acid (MAAsp), a polymerisable derivative of L-aspartic acid, and 2-hydroxyethyl methacrylate (HEMA). Monolithic columns [poly(2-hydroxyethyl methacrylate-N-methacryloyl-L-aspartic acid) (PHEMAsp)] were characterised by swelling studies, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The monolithic columns were used for IgG adsorption/desorption from aqueous solutions and human plasma. The IgG adsorption depended on the buffer type, and the maximum IgG adsorption from aqueous solution in phosphate buffer was 0.085 mg/g at pH 6.0. The monolithic columns allowed for one-step IgG purification with a negligible capacity decrease after ten adsorption-desorption cycles. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Fontainebleau Sand

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    2006-01-01

    The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand.......The report is a summary of results from laboratory tests in the geotechncial research group on Fontainebleau sand....

  15. Dopamine-imprinted monolithic column for capillary electrochromatography.

    Science.gov (United States)

    Aşır, Süleyman; Sarı, Duygu; Derazshamshir, Ali; Yılmaz, Fatma; Şarkaya, Koray; Denizli, Adil

    2017-11-01

    A dopamine-imprinted monolithic column was prepared and used in capillary electrochromatography as stationary phase for the first time. Dopamine was selectively separated from aqueous solution containing the competitor molecule norepinephrine, which is similar in size and shape to the template molecule. Morphology of the dopamine-imprinted column was observed by scanning electron microscopy. The influence of the organic solvent content of mobile phase, applied pressure and pH of the mobile phase on the recognition of dopamine by the imprinted monolithic column has been evaluated, and the imprinting effect in the dopamine-imprinted monolithic polymer was verified. Developed dopamine-imprinted monolithic column resulted in excellent separation of dopamine from structurally related competitor molecule, norepinephrine. Separation was achieved in a short period of 10 min, with the electrophoretic mobility of 5.81 × 10 -5  m 2 V -1 s -1 at pH 5.0 and 500 mbar pressure. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Enhanced mobility of non aqueous phase liquid (NAPL) during drying of wet sand

    Science.gov (United States)

    Govindarajan, Dhivakar; Deshpande, Abhijit P.; Raghunathan, Ravikrishna

    2018-02-01

    Enhanced upward mobility of a non aqueous phase liquid (NAPL) present in wet sand during natural drying, and in the absence of any external pressure gradients, is reported for the first time. This mobility was significantly higher than that expected from capillary rise. Experiments were performed in a glass column with a small layer of NAPL-saturated sand trapped between two layers of water-saturated sand. Drying of the wet sand was induced by flow of air across the top surface of the wet sand. The upward movement of the NAPL, in the direction of water transport, commenced when the drying effect reached the location of the NAPL and continued as long as there was significant water evaporation in the vicinity of NAPL, indicating a clear correlation between the NAPL rise and water evaporation. The magnitude and the rate of NAPL rise was measured at different water evaporation rates, different initial locations of the NAPL, different grain size of the sand and the type of NAPL (on the basis of different NAPL-glass contact angle, viscosity and density). A positive correlation was observed between average rate of NAPL rise and the water evaporation while a negative correlation was obtained between the average NAPL rise rate and the NAPL properties of contact angle, viscosity and density. There was no significant correlation of average NAPL rise rate with variation of sand grain size between 0.1 to 0.5 mm. Based on these observations and on previous studies reported in the literature, two possible mechanisms are hypothesized -a) the effect of the spreading coefficient resulting in the wetting of NAPL on the water films created and b) a moving water film due to evaporation that "drags" the NAPL upwards. The NAPL rise reported in this paper has implications in fate and transport of chemicals in NAPL contaminated porous media such as soils and exposed dredged sediment material, which are subjected to varying water saturation levels due to drying and rewetting.

  17. Column studies on BTEX biodegradation under microaerophilic and denitrifying conditions

    International Nuclear Information System (INIS)

    Hutchins, S.R.; Moolenaar, S.W.; Rhodes, D.E.

    1992-01-01

    Two column tests were conducted using aquifer material to simulate the nitrate field demonstration project carried out earlier at Traverse City, Michigan. The objectives were to better define the effect nitrate addition had on biodegradation of benzene, toluene, ethylbenzene, xylenes, and trimethylbenzenes (BTEX) in the field study, and to determine whether BTEX removal can be enhanced by supplying a limited amount of oxygen as a supplemental electron acceptor. Columns were operated using limited oxygen, limited oxygen plus nitrate, and nitrate alone. In the first column study, benzene was generally recalcitrant compared to the alkylbenzenes (TEX), although some removal did occur. In the second column study, nitrate was deleted from the feed to the column originally receiving nitrate alone and added to the feed of the column originally receiving limited oxygen alone. Although the requirement for nitrate for optimum TEX removal was clearly demonstrated in these columns, there were significant contributions by biotic and abiotic processes other than denitrification which could not be quantified

  18. Oil sands tailings leachability and toxicity evaluation

    International Nuclear Information System (INIS)

    Gulley, J.R.

    1995-01-01

    Fine tailings disposal and reclamation is a major issue facing the oil sands mining and extraction industry. Government regulations dictate that reclamation must return the site to a level of self-sustaining biological capability which approximates the natural condition. A two-phase laboratory program has been completed to investigate the suitability of alternative reclamation materials. For the first phase of the study, chemical and toxicological analyses were carried out on 13 different reclamation and reference materials (solid phase and extractions). Seedling emergence, nematode maturation, algal growth and bacterial luminescence for leachate samples showed a range of sensitivities in response to the tested materials, although phytotoxicity tests were generally the most sensitive. With the exception of one test material, high toxicity ratings were consistent with that expected from the chemical data. The second phase of the study focused on the evaluation of chemical and toxicological conditions in leachate water generated using bench-scale column percolation tests. Leachate water equivalent to 10 pore volume replacements was generated and temporal variations in toxicity and chemistry monitored. Similar to phase 1 findings, phytotoxicity tests were the most sensitive tests to leachate waters. For most materials tested, most toxicity was removed after 2--3 porewater replacements. More persistent toxicity was noted for samples containing bitumen (e.g., fine tails and oil sands). No clear correspondence was noted between chemical concentrations and toxicity in leachate waters

  19. Influence of second kind collisions on the electron distribution function in the positive column of low pressure nitrogen discharge

    International Nuclear Information System (INIS)

    Rohlena, K.; Ruzicka, T.

    1979-01-01

    A numerical solution of the Boltzmann equation for the electron gas in the positive column of a DC discharge in nitrogen is presented. The Boltzmann equation was solved with the inclusion of the second-kind (superelastic) collisions proceeding from the first six excited vibrational levels of molecular nitrogen. The vibrational level population is supposed to follow the Boltzmann distribution for the given vibrational temperature Tsub(v), with a possible deviation of the ground level, which can be overpopulated in the given ratio γ. Apart from the electron distribution functions, which were gained for various values of E/p 0 , Tsub(v) and γ, the values of some production frequencies and kinetic coefficients are presented in form of tables and plots. It is found that the electron distribution (and also the corresponding production rates) only above a certain energy limit depends on Tsub(v) and γ through the normalization constant. (author)

  20. Removal of heavy metals using a microbial active, continuously operated sand filter

    International Nuclear Information System (INIS)

    Ebner, C.

    2001-01-01

    influence the bacterial biomass production. A sand column system with partial circulation of the waste water was constructed for the treatment of toxic waste waters. Using this experimental set-up a resistant biofilm was built up by continuous increase of waste water concentration. With this biofilm-system it is possible to treat waste waters, which completely inhibit bacterial growth with freely suspended cells in batch culture. The selection of suitable nutrients for the bacteria turned out to be crucial for the efficiency of the metal removal process too. From all essential macro- and micro-elements only C, N and P had to be added to the waste waters, in some cases the addition of a carbon source was sufficient. All other nutrients were already present in the waste waters. In order to optimize the nutrient supplementation, various carbon and nitrogen sources were checked concerning biomass production and metal removal. Some nutrient sources strongly supported bacterial growth, but simultaneously reduced metal removal by unfavorable chemical interactions with heavy metals. From all nutrient sources tested, Na-acetate turned out to be the best choice for carbon supply of the bacteria. If the addition of nitrogen to the waste water is necessary, nitrate, ammonia or urea are suitable sources for bacterial growth and metal removal. In experiments with single fixed bed columns (100 cm 3 sand) and subsequent tests in the lab-scale (10 dm 3 sand) and pilot scale sand filter (1,7 m 3 sand), a suitable procedure for the inoculation of the sand filter and the formation of biofilm on the sand grains was developed. The maintenance of stock cultures was carried out on agar plates made of waste water, enriched with missing nutrients. Production of the biomass for inoculation was realized in liquid culture using waste water, enriched with nutrients too. The formation of a biofilm on the sand grains was achieved by addition of the liquid culture to the sand filter, supply of nutrients

  1. Effect of mobilities and electric field on the stability of magnetized positive column

    International Nuclear Information System (INIS)

    Dogra, V.K.; Uberoi, M.S.

    1983-01-01

    The effect of ratio of the mobilities of electrons and ions and non-dimensional electric field, on the stability of magnetized positive column for all unstable modes is studied in a self-consistent formulation for the perturbations of plasma density and electric potential. The minimum non-dimensional electric field at which magnetized positive column becomes unstable for different ratios of the mobilities of electrons and ions is also investigated. (author)

  2. New generation expandable sand screens

    OpenAIRE

    Syltøy, Christer

    2014-01-01

    Master's thesis in Petroleum engineering This thesis aims to give a general insight into sand control and various sorts of sand control measures and applications of sand control tools. Special focus will be given to expandable sand screens – a technology which came about in the late 1990’s through the use of flexible, expandable tubulars as base pipe in sand screens. More specifically Darcy’s Hydraulic Endurance Screens, a compliant sand screen system using hydraulic activation, and the fu...

  3. Saltation of non-spherical sand particles.

    Directory of Open Access Journals (Sweden)

    Zhengshi Wang

    Full Text Available Saltation is an important geological process and the primary source of atmospheric mineral dust aerosols. Unfortunately, no studies to date have been able to precisely reproduce the saltation process because of the simplified theoretical models used. For example, sand particles in most of the existing wind sand movement models are considered to be spherical, the effects of the sand shape on the structure of the wind sand flow are rarely studied, and the effect of mid-air collision is usually neglected. In fact, sand grains are rarely round in natural environments. In this paper, we first analyzed the drag coefficients, drag forces, and starting friction wind speeds of sand grains with different shapes in the saltation process, then established a sand saltation model that considers the coupling effect between wind and the sand grains, the effect of the mid-air collision of sand grains, and the effect of the sand grain shape. Based on this model, the saltation process and sand transport rate of non-spherical sand particles were simulated. The results show that the sand shape has a significant impact on the saltation process; for the same wind speed, the sand transport rates varied for different shapes of sand grains by as much as several-fold. Therefore, sand shape is one of the important factors affecting wind-sand movement.

  4. Khnifiss Beach's Black Sand: Provenance and Transport Pathways Investigation Using Heavy Minerals' Characterization

    Science.gov (United States)

    Adnani, M.; Elbelrhiti, H.; Ahmamou, M.; Masmoudi, L.

    2014-12-01

    Arid areas in south of Morocco suffer from silting problem causing destruction of villages infrastructure, roads, agriculture land and oasis heritage. Black sand on Khnifiss beach near Tarfaya city (S-W Morocco) is marked by enrichment of heavy minerals. This later is an important fraction that could help to assess the provenance and transport pathways of sediment. The sand's origin investigation could be useful to fight against erosion and silting problems from the source of supply, to this end, mineralogical analysis was carried out in Khnifiss beach's sand using Optic Microscope and Scanning Electronic Microscope with dispersive energy (SEM- EDS), in addition to physico-chemical analysis provided by Electronic Microprobe. The results revealed: (i) a high grade of oxides (Rutile, Ilmenite, Magnetite, Ulvöspinel) in samples, (ii) silicates (Quartz, Clinopyroxene, feldspar, Zircon), (iii) phosphate (apatite) and (iv) carbonate (calcite). The dominance of iron oxides justifies the black sand's colour. Then, the mineral composition supposes interference between different origins: proximal source (Calcareous cliff) for calcite, distal sources of oxides and silicates are supposed to be eroded and carried by Drâa valley from granite and igneous rocks in Anti-Atlasic field. Another source supposed might be a proximal volcanic island (Canaries island).

  5. Experimental Study on Unconfined Compressive Strength of Organic Polymer Reinforced Sand

    Directory of Open Access Journals (Sweden)

    Jin Liu

    2018-01-01

    Full Text Available The natural sand is loose in structure with a small cohesive force. Organic polymer can be used to reinforce this sand. To assess the effectiveness of organic polymer as soil stabilizer (PSS, a series of unconfined compressive strength tests have been performed on reinforced sand. The focus of this study was to determine a curing method and a mix design to stabilize sand. The curing time, PSS concentration, and sand density were considered as variables in this study. The reinforcement mechanism was analyzed with images of scanning electron microscope (SEM. The results indicated that the strength of stabilized sand increased with the increase in the curing time, concentration, and sand density. The strength plateaus are at about curing time of 48 h. The UCS of samples with density of 1.4 g/cm3 at 10%, 20%, 30%, 40%, and 50% PSS concentration are 62.34 kPa, 120.83 kPa, 169.22 kPa, 201.94 kPa, and 245.28 kPa, respectively. The UCS of samples with PSS concentration of 30% at 1.4 g/cm3, 1.5 g/cm3, and 1.6 g/cm3 density are 169.22 kPa, 238.6 kPa 5, and 281.69 kPa, respectively. The chemical reaction between PSS and sand particle is at its microlevel, which improves the sand strength by bonding its particles together and filling the pore spaces. In comparison with the traditional reinforcement methods, PSS has the advantages of time saving, lower cost, and better environment protection. The research results can be useful for practical engineering applications, especially for reinforcement of foundation, embankment, and landfill.

  6. A combined CFD-experimental method for developing an erosion equation for both gas-sand and liquid-sand flows

    Science.gov (United States)

    Mansouri, Amir

    gas-sand, water-sand and viscous liquid-sand flows with high accuracy. Furthermore, in order to gain a better understanding of the erosion mechanism, a comprehensive experimental study was conducted to investigate the important factors influencing the erosion rate in gas-sand and slurry flows. The wear pattern and total erosion ratio were measured in a direct impingement jet geometry (for both dry impact and submerged impingement jets). The effects of fluid viscosity, abrasive particle size, particle impact speed, jet inclination angle, standoff distance, sand concentration, and exposure time were investigated. Also, the eroded samples were studied with Scanning Electron Microscopy (SEM) to understand the erosion micro-structure. Also, the sand particle impact speed and angle were measured using a Particle Image Velocimetry (PIV) system. The measurements were conducted in two types of erosion testers (gas-solid and liquid-solid impinging jets). The Particle Tracking Velocimetry (PTV) technique was utilized which is capable of tracking individual small particles. Moreover, CFD modeling was performed to predict the particle impact data. Very good agreement between the CFD results and PTV measurements was observed.

  7. Effect of high-energy electron irradiation in an electron microscope column on fluorides of alkaline earth elements (CaF2, SrF2, and BaF2)

    International Nuclear Information System (INIS)

    Nikolaichik, V. I.; Sobolev, B. P.; Zaporozhets, M. A.; Avilov, A. S.

    2012-01-01

    The effect of high-energy (150 eV) electron irradiation in an electron microscope column on crystals of fluorides of alkaline earth elements CaF 2 , SrF 2 , and BaF 2 is studied. During structural investigations by electron diffraction and electron microscopy, the electron irradiation causes chemical changes in MF 2 crystals such as the desorption of fluorine and the accumulation of oxygen in the irradiated area with the formation of oxide MO. The fluorine desorption rate increases significantly when the electron-beam density exceeds the threshold value of ∼2 × 10 3 pA/cm 2 ). In BaF 2 samples, the transformation of BaO into Ba(OH) 2 was observed when irradiation stopped. The renewal of irradiation is accompanied by the inverse transformation of Ba(OH) 2 into BaO. In the initial stage of irradiation of all MF 2 compounds, the oxide phase is in the single-crystal state with a lattice highly matched with the MF 2 matrix. When the irradiation dose is increased, the oxide phase passes to the polycrystalline phase. Gaseous products of MF 2 destruction (in the form of bubbles several nanometers in diameter) form a rectangular array with a period of ∼20 nm in the sample.

  8. Morphological characterization of ceramic fillers made from Indonesian natural sand as restorative dental materials

    Science.gov (United States)

    Karlina, E.; Susra, S.; Fatmala, Y.; Hartoyo, H. M.; Takarini, V.; Usri, K.; Febrida, R.; Djustiana, N.; Panatarani, C.; Joni, I. M.

    2018-02-01

    Dental composite as restorative dental materials can be reinforced using ceramic fillers. Homogeneous distribution of filler particles shall improve its mechanical properties. This paper presents the results of the preliminary study on the ZrO2-Al2O3-SiO2 ceramic fillers made from Indonesian natural sand that can increase the mechanical properties of dental composite. The synthesis was done using zirconium silicate sand (ZrSiO4) and aluminium oxide (Al2O3) precursors, which dissolved together with 70:30 weight ratios. Two types of sand were used: (1) manufactured sand (mesh #80) and (2) natural sand (mesh #400). The samples then heated in the furnace at 1100 °C for 8 hours. The morphological characterization was then evaluated using JEOL Scanning Electron Microscope (SEM) for the surface structure that analyze particles size and distribution. Ceramic fillers made from natural sand is homogenous, well distributed with average particle size of 5-10 µm. Comparably, ceramic filler made from the manufactured sand is heterogeneous, poorly distributed and appear as agglomerates with average particle size are 30-50 µm. The results suggest that ceramic fillers made from natural sand demonstrate better character to represent as a functional restorative dental material.

  9. A stochastic view on column efficiency.

    Science.gov (United States)

    Gritti, Fabrice

    2018-03-09

    A stochastic model of transcolumn eddy dispersion along packed beds was derived. It was based on the calculation of the mean travel time of a single analyte molecule from one radial position to another. The exchange mechanism between two radial positions was governed by the transverse dispersion of the analyte across the column. The radial velocity distribution was obtained by flow simulations in a focused-ion-beam scanning electron microscopy (FIB-SEM) based 3D reconstruction from a 2.1 mm × 50 mm column packed with 2 μm BEH-C 18 particles. Accordingly, the packed bed was divided into three coaxial and uniform zones: (1) a 1.4 particle diameter wide, ordered, and loose packing at the column wall (velocity u w ), (2) an intermediate 130 μm wide, random, and dense packing (velocity u i ), and (3) the bulk packing in the center of the column (velocity u c ). First, the validity of this proposed stochastic model was tested by adjusting the predicted to the observed reduced van Deemter plots of a 2.1 mm × 50 mm column packed with 2 μm BEH-C 18 fully porous particles (FPPs). An excellent agreement was found for u i  = 0.93u c , a result fully consistent with the FIB-SEM observation (u i  = 0.95u c ). Next, the model was used to measure u i  = 0.94u c for 2.1 mm × 100 mm column packed with 1.6 μm Cortecs-C 18 superficially porous particles (SPPs). The relative velocity bias across columns packed with SPPs is then barely smaller than that observed in columns packed with FPPs (+6% versus + 7%). u w =1.8u i is measured for a 75 μm × 1 m capillary column packed with 2 μm BEH-C 18 particles. Despite this large wall-to-center velocity bias (+80%), the presence of the thin and ordered wall packing layer has no negative impact on the kinetic performance of capillary columns. Finally, the stochastic model of long-range eddy dispersion explains why analytical (2.1-4.6 mm i.d.) and capillary (columns can all be

  10. Liquefaction resistance of calcareous sands

    International Nuclear Information System (INIS)

    Sandoval Vallejo, Eimar

    2012-01-01

    Calcareous sands are unique in terms of their origin, mineralogy, shape, fragility and intra particle porosity. This article presents results from an experimental program carried out to study the liquefaction resistance of a calcareous sand retrieved from Cabo Rojo at Puerto Rico. The experimental program included mineralogical characterization, index properties, and undrained cyclic triaxial tests on isotropically consolidated reconstituted samples. Due to the large variation in the calcareous sand properties, results are compared with previous researches carried out on other calcareous sands around the world. Results showed a wide range in the liquefaction resistance of the studied calcareous sands. Cabo Rojo sand experienced greater liquefaction resistance than most of the calcareous sands used for comparison. Important differences in the excess pore pressure generation characteristics were also found.

  11. Final design and construction issues of the TAPIRO epithermal column

    International Nuclear Information System (INIS)

    Burn, K.W.; Casalini, L.; Nava, E.; Tinti, R.; Martini, S.; Mondini, D.; Rosi, G.

    2006-01-01

    The construction of the epithermal column for clinical trials at the 5 kW fast reactor TAPIRO (ENEA, Casaccia, Italy) has been completed, the experimental bunker in the reactor hall has been designed and the beam characterisation will shortly be underway. As has been reviewed at the last two ICNCT conferences, the low power of the neuron source and the relatively distant patient position outside the reactor shield led to a column design with certain characteristics. One consequence is the employment of a collimator containing lead of high purity with the resultant problems of mechanical construction. Another is the substantial neutron leakage from the column outside the aperture into the experimental bunker. Furthermore the absence of a gamma shield has led to an electron dose to the skin. This is resolved with an electron shield of aluminium. Here the construction and final design issues are discussed and the state of the project is presented. (author)

  12. Different depth intermittent sand filters for laboratory treatment of synthetic wastewater with concentrations close to measured septic tank effluent.

    Science.gov (United States)

    Rodgers, M; Walsh, G; Healy, M G

    2011-01-01

    The objective of this study was to apply hydraulic and chemical oxygen demand (COD) loading rates at the upper limits of the design criteria for buried sand filters to test the sand filter depth design criteria. Over a 274-day study duration, synthetic effluent with a strength of domestic wastewater was intermittently dosed onto two sand filters of 0.2 m diameter, with depths of 0.3 and 0.4 m. Hydraulic and organic carbon loading rates of 105 L m(-2) d(-1) and 40 g COD m(-2) d(-1), respectively, were applied to the filters. The filters did not clog and had good effluent removal capabilities for 274 and 190 days, respectively. However, the 0.3 m-deep filter did experience a reduced performance towards the end of the study period. In the 0.3 and 0.4 m-deep filters, the effluent COD and SS concentrations were less than 86 and 31 mg L(-1), respectively, and nitrification was nearly complete in both these columns. Ortho-phosphorus (PO(4)-P) removal in fine sand and laterite 'upflow' filters, receiving effluent from the 0.3 m-deep filter, was 10% and 44%, respectively.

  13. Synthesis and characterization of mangan oxide coated sand from Capkala kaolin

    Science.gov (United States)

    Destiarti, Lia; Wahyuni, Nelly; Prawatya, Yopa Eka; Sasri, Risya

    2017-03-01

    Synthesis and characterization of mangan oxide coated sand from quartz sand fraction of Capkala kaolin has been conducted. There were two methods on synthesis of Mangan Oxide Coated Sand (MOCS) from Capkala Kaolin compared in this research. Characterization of MOCS was done by using Scanning Electron Microscope/Energy Dispersive X-Ray Spectrometer (SEM/EDX) and X-Ray Diffraction (XRD). The MOCS was tested to reduce phosphate in laundry waste. The result showed that the natural sand had bigger agregates and a relatively uniform structural orientation while both MOCS had heterogen structural orientation and manganese oxide formed in cluster. Manganese in first and second methods were 1,93% and 2,63%, respectively. The XRD spectrum showed clear reflections at 22,80°, 36,04°, 37,60° and a broad band at 26,62° (SiO2). Based on XRD spectrum, it can be concluded that mineral constituents of MOCS was verified corresponding to pyrolusite (MnO2). The former MOCS could reduce almost 60% while the later could reduce 70% phosphate in laundry waste.

  14. MECHANICAL REGENERATION OF SAND WASTE

    Directory of Open Access Journals (Sweden)

    D. I. Gnir

    2005-01-01

    Full Text Available The experimental activation of the sand regenerator of the firm SINTO is carried out at ОАО “MZOO". It is shown that sand grains are cleared from films of binding agents, that allows to use the treated sand for preparation of agglutinant and core sands.

  15. Electron energy distribution function in the positive column of a neon glow discharge using the black wall approximation

    International Nuclear Information System (INIS)

    Al-Hawat, Sh; Naddaf, M

    2005-01-01

    The electron energy distribution function (EEDF) was determined from the second derivative of the I-V Langmuir probe characteristics and, thereafter, theoretically calculated by solving the plasma kinetic equation, using the black wall (BW) approximation, in the positive column of a neon glow discharge. The pressure has been varied from 0.5 to 4 Torr and the current from 10 to 30 mA. The measured electron temperature, density and electric field strength were used as input data for solving the kinetic equation. Comparisons were made between the EEDFs obtained from experiment, the BW approach, the Maxwellian distribution and the Rutcher solution of the kinetic equation in the elastic energy range. The best conditions for the BW approach are found to be under the discharge conditions: current density j d = 4.45 mA cm -2 and normalized electric field strength E/p = 1.88 V cm -1 Torr -1

  16. Electron energy distribution function in the positive column of a neon glow discharge using the black wall approximation

    Science.gov (United States)

    Al-Hawat, Sh; Naddaf, M.

    2005-04-01

    The electron energy distribution function (EEDF) was determined from the second derivative of the I-V Langmuir probe characteristics and, thereafter, theoretically calculated by solving the plasma kinetic equation, using the black wall (BW) approximation, in the positive column of a neon glow discharge. The pressure has been varied from 0.5 to 4 Torr and the current from 10 to 30 mA. The measured electron temperature, density and electric field strength were used as input data for solving the kinetic equation. Comparisons were made between the EEDFs obtained from experiment, the BW approach, the Maxwellian distribution and the Rutcher solution of the kinetic equation in the elastic energy range. The best conditions for the BW approach are found to be under the discharge conditions: current density jd = 4.45 mA cm-2 and normalized electric field strength E/p = 1.88 V cm-1 Torr-1.

  17. Phosphate limitation in biological rapid sand filters used to remove ammonium from drinking water

    DEFF Research Database (Denmark)

    Lee, Carson Odell; Albrechtsen, Hans-Jørgen; Smets, Barth F.

    2013-01-01

    Removing ammonium from drinking water is important for maintaining biological stability in distribution systems. This is especially important in regions that do not use disinfectants in the treatment process or keep a disinfectant residual in the distribution system. Problems with nitrification c...... a pilot scale sand column which initial analysis confirmed performed similarly to the full scale filters. Long term increased ammonium loads were applied to the pilot filter both with and without phosphate addition. Phosphate was added at a concentration of 0.5 mg PO4-P/L to ensure...

  18. Thomson scattering in a low-pressure argon mercury positive column

    NARCIS (Netherlands)

    Bakker, L.P.; Kroesen, G.M.W.

    2000-01-01

    The electron density and the electron temperature in a low-pressure argon mercury positive column are determined using Thomson scattering. Special attention has been given to the stray light reduction in the Thomson scattering setup. The results are obtained in a discharge tube with a 26 mm diam, 5

  19. Thomson scattering in a low-pressure neon mercury positive column

    NARCIS (Netherlands)

    Bakker, L.P.; Kroesen, G.M.W.

    2001-01-01

    The electron density and the electron temperature in a low-pressure neon mercury positive column are determined using Thomson scattering. Special attention has been given to the stray light reduction in the Thomson scattering setup. The results are obtained in a discharge tube with a 26 mm diam, 10

  20. Modeling Stone Columns.

    Science.gov (United States)

    Castro, Jorge

    2017-07-11

    This paper reviews the main modeling techniques for stone columns, both ordinary stone columns and geosynthetic-encased stone columns. The paper tries to encompass the more recent advances and recommendations in the topic. Regarding the geometrical model, the main options are the "unit cell", longitudinal gravel trenches in plane strain conditions, cylindrical rings of gravel in axial symmetry conditions, equivalent homogeneous soil with improved properties and three-dimensional models, either a full three-dimensional model or just a three-dimensional row or slice of columns. Some guidelines for obtaining these simplified geometrical models are provided and the particular case of groups of columns under footings is also analyzed. For the latter case, there is a column critical length that is around twice the footing width for non-encased columns in a homogeneous soft soil. In the literature, the column critical length is sometimes given as a function of the column length, which leads to some disparities in its value. Here it is shown that the column critical length mainly depends on the footing dimensions. Some other features related with column modeling are also briefly presented, such as the influence of column installation. Finally, some guidance and recommendations are provided on parameter selection for the study of stone columns.

  1. Preparation and characterization of poly(acrylic acid)—corn starch blend for use as chemical sand-fixing materials

    Science.gov (United States)

    Dang, Xugang; Chen, Hui; Shan, Zhihua

    2017-07-01

    One chemical sand-fixing materials based on poly(acrylic acid)-corn starch (PACS) blend was studied in this work. The PACS blend was prepared by solution mixing method between PA and CS. In order to prepare sand-fixing materials for environmental applications using the well-established method of spraying evenly PACS blend solution on the surfaces of fine sand. Fourier transform infrared spectroscopy (FT-IR) revealed the existence of the intermolecular interactions between the blend components. Scanning electron microscope (SEM) analysis showed a continuous phase of blend, and it also showed the good sand-fixing capacity. The test results of hygroscopicity and water retention experiments indicated that the blends had excellent water-absorbing and water-retention capacity. The results of contact angle measurements between the PACS solutions and fine sand showed that the PACS blend has a satisfactory effect on fine sand wetting. And the PACS, as a sand-fixation material, has excellent sand-fixation rate up to 99.5%.

  2. Post column derivatisation analyses review. Is post-column derivatisation incompatible with modern HPLC columns?

    Science.gov (United States)

    Jones, Andrew; Pravadali-Cekic, Sercan; Dennis, Gary R; Shalliker, R Andrew

    2015-08-19

    Post Column derivatisation (PCD) coupled with high performance liquid chromatography or ultra-high performance liquid chromatography is a powerful tool in the modern analytical laboratory, or at least it should be. One drawback with PCD techniques is the extra post-column dead volume due to reaction coils used to enable adequate reaction time and the mixing of reagents which causes peak broadening, hence a loss of separation power. This loss of efficiency is counter-productive to modern HPLC technologies, -such as UHPLC. We reviewed 87 PCD methods published from 2009 to 2014. We restricted our review to methods published between 2009 and 2014, because we were interested in the uptake of PCD methods in UHPLC environments. Our review focused on a range of system parameters including: column dimensions, stationary phase and particle size, as well as the geometry of the reaction loop. The most commonly used column in the methods investigated was not in fact a modern UHPLC version with sub-2-micron, (or even sub-3-micron) particles, but rather, work-house columns, such as, 250 × 4.6 mm i.d. columns packed with 5 μm C18 particles. Reaction loops were varied, even within the same type of analysis, but the majority of methods employed loop systems with volumes greater than 500 μL. A second part of this review illustrated briefly the effect of dead volume on column performance. The experiment evaluated the change in resolution and separation efficiency of some weak to moderately retained solutes on a 250 × 4.6 mm i.d. column packed with 5 μm particles. The data showed that reaction loops beyond 100 μL resulted in a very serious loss of performance. Our study concluded that practitioners of PCD methods largely avoid the use of UHPLC-type column formats, so yes, very much, PCD is incompatible with the modern HPLC column. Copyright © 2015. Published by Elsevier B.V.

  3. Evaluation of sorption affinity of cadmium(II) on Haro river sand from aqueous solutions

    International Nuclear Information System (INIS)

    Hasany, S.M.; Chaudhary, M.H.

    2001-01-01

    The sorption of Cd(II) on Haro river sand from deionized water is reported. The sorption system obeyed according to the Freundlich and Dubinin-Radushkevich (D-R) isotherms. The Freundlich parameters 1/n = 0.67±0.05 and of A = 1.38±1.14 mmole x g -1 have been ascertained. D-R isotherm yields the values of β = -0.003741±0.000321 kJ 2 x mole -2 , X m = 0.23±0.21 μmole x g -1 and of E = 11.6±0.5 kJ x mole -1 . The influence of common anions and cations on the sorption was examined. Trivalent Bi enhances the sorption whereas Fe, Cr, Al and chromate ions reduce the sorption significantly. Hf(IV) and Ag(I) indicate substantial sorption (61-98%) whereas Gd(III), Re(VII) and Sc(III) show low sorption (<5%). The elements having low sorption can be separated from elements indicating higher sorption using Haro river sand column. (author)

  4. Crushed rock sand – An economical and ecological alternative to natural sand to optimize concrete mix

    Directory of Open Access Journals (Sweden)

    Sanjay Mundra

    2016-09-01

    Full Text Available The study investigates the use of crushed rock sand as viable alternative to Natural River sand that is being conventionally used as fine aggregate in cement concrete. Various mix designs were developed for different grades of concrete based on IS, ACI and British codes using Natural River sand and crushed rock sand. In each case, the cube compressive strength test, and beam flexure tests were conducted. The results of the study show that, the strength properties of concrete using crushed rock sand are nearly similar to the conventional concrete. The study has shown that crushed stone sand can be used as economic and readily available alternative to river sand and can therefore help to arrest the detrimental effects on the environment caused due to excessive mining of river sand.

  5. Hydrothermal synthesis and magneto-optical properties of Ni-doped ZnO hexagonal columns

    International Nuclear Information System (INIS)

    Xu, Xingyan; Cao, Chuanbao

    2015-01-01

    Single crystal Zn 1−x Ni x O (x=0, 0.02, 0.04, 0.06) hexagonal columns have been synthesized by a simple hydrothermal route. The hexagonal columns of the products are about 3 μm in diameter and about 2 μm in thickness. X-ray diffraction (XRD), Ni K-edge XANES spectra and TEM indicate that the as-prepared samples are single-crystalline wurtzite structure and no metallic Ni or other secondary phases are found in the hexagonal columns. Optical absorption and Raman results further confirm the incorporation of Ni 2+ ions in the ZnO lattice. Magnetic measurements indicate that the Zn 1−x Ni x O hexagonal columns exhibited obvious ferromagnetic characteristic at room temperature. The coercive fields (H c ) were obtained to be 135.3, 327.79 and 127.29 Oe for x=0.02, 0.04 and 0.06, respectively. The ferromagnetism was assumed to originate from the exchange interaction between free carriers (holes or electrons) from the valence band and the localized d spins on the Ni ions. - Highlights: • Single crystal Zn 1−x Ni x O (x=0, 0.02, 0.04, 0.06) hexagonal columns were synthesized by a simple hydrothermal method. • The layer-by-layer growth manner of the Zn 1−x Ni x O hexagonal columns was proposed. • Obvious room-temperature ferromagnetic characteristic of Zn 1−x Ni x O are observed and the coercivity (H c ) are 135.3,327.79 and 127.29 Oe for x=0.02, 0.04 and 0.06, respectively. • The exchange interaction between local-spin polarized electrons and conduction electrons is responsible for the room-temperature ferromagnetism in the Zn 1−x Ni x O hexagonal columns

  6. Transport processes in intertidal sand flats

    Science.gov (United States)

    Wu, Christy

    2010-05-01

    Methane rich sulfate depleted seeps are observed along the low water line of the intertidal sand flat Janssand in the Wadden Sea. It is unclear where in the flat the methane is formed, and how it is transported to the edge of the sand flat where the sulfidic water seeps out. Methane and sulfate distributions in pore water were determined along transects from low water line toward the central area of the sand flat. The resulting profiles showed a zone of methane-rich and sulfate-depleted pore water below 2 m sediment depth. Methane production and sulfate reduction are monitored over time for surface sediments collected from the upper flat and seeping area. Both activities were at 22 C twice as high as at 15 C. The rates in sediments from the central area were higher than in sediments from the methane seeps. Methanogenesis occurred in the presence of sulfate, and was not significantly accelerated when sulfate was depleted. The observations show a rapid anaerobic degradation of organic matter in the Janssand. The methane rich pore water is obviously transported with a unidirectional flow from the central area of the intertidal sand flat toward the low water line. This pore water flow is driven by the pressure head caused by elevation of the pore water relative to the sea surface at low tide (Billerbeck et al. 2006a). The high methane concentration at the low water line accumulates due to a continuous outflow of pore water at the seepage site that prevents penetration of electron acceptors such as oxygen and sulfate to reoxidize the reduced products of anaerobic degradation (de Beer et al. 2006). It is, however, not clear why no methane accumulates or sulfate is depleted in the upper 2 m of the flats.

  7. Rheological Characterization of Green Sand Flow

    DEFF Research Database (Denmark)

    Jabbaribehnam, Mirmasoud; Spangenberg, Jon; Hovad, Emil

    2016-01-01

    The main aim of this paper is to characterize experimentally the flow behaviour of the green sand that is used for casting of sand moulds. After the sand casting process is performed, the sand moulds are used for metal castings. The rheological properties of the green sand is important to quantif...

  8. Preparation of β-cyclodextrin-gold nanoparticles modified open tubular column for capillary electrochromatographic separation of chiral drugs.

    Science.gov (United States)

    Zhou, Li; Jiang, Shenmeng; Zhang, Xue; Fang, Linlin; Guo, Xingjie

    2018-04-01

    In this paper, β-cyclodextrin (β-CD) modified gold nanoparticles (AuNPs) coated open tubular column (OT column) was prepared for capillary electrochromatography. The open tubular column was constructed through self-assembly of gold nanoparticles on 3-mercaptopropyl-trimethoxysilane (MPTMS) prederivatized capillary and subsequent modification of thiols β-cyclodextrin (SH-β-CD). Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet visible spectroscopy were carried out to characterize the prepared open tubular column and synthesized gold nanoparticles. By comparing different coating times of gold nanoparticles and thiols β-cyclodextrin, we got the optimal conditions for preparing the open tubular column. Also, the separation parameters were optimized including buffer pH, buffer concentration and applied voltage. Separation effectiveness of open tubular column was verified by the separation of four pairs of drug enantiomers including bifonazole, fexofenadine, omeprazole and lansoprazole, and satisfactory separation results were achieved for these analytes studied. In addition, the column showed good stability and repeatability. The relative standard deviation values less than 5% were obtained through intra-day, inter-day, and column-to-column investigations. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Effect of Gamma Irradiation on Polymer Modified White Sand Cement Mortar Composites

    International Nuclear Information System (INIS)

    Khattab, M.M.

    2012-01-01

    This study focuses on the substitution effect of standard sand of conventional cement mortar made from ordinary Portland cement (OPC) and standard sand (SS) OPC/SS 1:3; by different ratios of white sand (WS) powder to prepare three types of white sand cement mortar designated as 1OPC:2SS:1WS, 1OPC:1SS:2WS and 1OPC:0SS:3WS. The prepared samples were first cured under tap water for different time intervals namely 3, 7, 28 and 90 days. The effect of addition of 10% styrene-acrylic ester (SAE) as well as the effect of different doses of gamma rays (10, 20, 30 and 50 kGy) on the physicomechanical properties of polymer modified white sand cement mortar specimens also discussed. Compression strength test, total porosity and water absorption percentages were measured according to standard specifications. The obtained data indicated that, the cement mortar samples containing different ratios of white sand have lower values of compressive strength as compared to the conventional cement mortar while, the percentages of total porosity and water absorption increased. On the other hand, the polymer modified mortar specimens showed a noticeably enhancement in the physico-mechanical properties under the effect of gamma-radiation than those of untreated samples. These results were confirmed by scanning electron microscopy (SEM), and thermogravimetric analysis (TGA) studies

  10. Improved focusing-and-deflection columns

    International Nuclear Information System (INIS)

    Mui, P.H.; Szilagyi, M.

    1995-01-01

    Our earlier design procedures for constructing quadrupole columns are further expanded to include octupole corrector units and ''octupole'' deflectors with no third-order harmonics. The additional complications are finer partitioning of the plates and increased number of voltage controllers. Two sample designs, one having only the additional octupole deflectors and one having both the deflectors and the correctors, are presented and compared to our previous quadrupole system. The additional octupole components are shown to be capable of increasing the current density from 30% to more than 300% for a four-plate system, designed to focus and scan the electron beam over a circular area of 0.25 mm radius. The electron beam is assumed to have an initial divergence of ±2.3 mrad, an initial energy of 6 kV, a total energy spread of 1 eV, and a final acceleration of 30 keV. These systems are then slightly reoptimized for a superficial comparison with the commercially available column by Micrion Corporation. The numerical results indicate a potential for substantial improvements, demonstrating the power of this design procedure. Finally, a discussion is presented on how the individual components can interact with each other to reduce the various aberrations. copyright 1995 American Vacuum Society

  11. The Alberta oil sands story

    Energy Technology Data Exchange (ETDEWEB)

    1974-01-01

    This report serves as a detailed introduction to the Alberta oil sands and their development. It includes a description of the oil sands deposits, an outline of crude bitumen recovery and upgrading processes, the role of Alberta Energy Company in oil sands development, environmental aspects, manpower requirements for oil sands development, research needs, and further oil sands projects. Presently proven recoverable reserves in the oil sands amount to 26.5 billion bbl of synthetic crude. Production from the Syncrude plant (125,000 bbl/d capacity) is expected to begin in 1977, followed by a Shell Canada operation around 1980. The provincial government will participate in the oil sand industry through its joint venture participation in Syncrude and its 50% share in Alberta Energy Company; the latter company participates in related aspects of the Syncrude project, such as pipelines. The result of Alberta's participation in the industry will mean that, directly or indirectly, the province will realize 60% of the total profits. The job creation potential of oil sands projects is estimated to be extensive, with a direct and indirect work force supported by oil sands activities possibly reaching 180,000 persons by the year 2000. Research needs have been identified, particularly in the area of in-situ thermal recovery technology, and the creation of the Alberta Oil Sands Technology and Research Authority has been authorized in order to meet these needs. Although current reserves are sufficient to support 20-30 synthetic crude plants, a number of factors will limit expansion of the industry. 8 figs., 5 tabs.

  12. Hydrodynamic calculation of a filter sand bed type used in the containment venting systems

    International Nuclear Information System (INIS)

    Cuevas V, D.; Sainz M, E.; Ortiz V, J.

    2015-09-01

    The filtered venting of the containment has been adopted in European countries to mitigate the consequences of excess pressure containment during a severe accident. When venting has taken place, the fission products are released directly into the environment, unless a filter on the same path is placed, so that various types of filters are used to trap the fission products. The venting filters of the containment currently installed use different filtration technologies that involve more than one medium. Those using water as the first stage of filtration are called wet systems and are equipped with additional steps to remove water drops and fine aerosols emissions. And even they may also be equipped with an element containing certain absorption means for the filtration of gaseous iodine species. Other designs based on filtration of deep bed as the primary retention step; called dry filters, use filtration media of metal fiber, ceramic or sand to trap aerosols. This paper evaluates the hydraulic characteristics of the filter sand bed type designed by EDF as a candidate to be installed in the containment of BWR Mark II (type of primary containment of the nuclear power plant of Laguna Verde). The evaluation of filter sand bed type was performed using the software package of open source OpenFOAM. Models of each zone of the filtered device were generated and through a series of parametric calculations of computational fluid mechanics relevant hydrodynamic characteristics of the device were obtained, such as pressure drops against mass flow rate and pressure fields and speed at different operating conditions. On the other hand, the model validation of the sand bed filter when comparing the results of experimental tests on a sand column of PITEAS program (1985-1986) against OpenFOAM simulation was realized. The results are very close to those obtained experimentally. (Author)

  13. External morphology of sensory structures of fourth instar larvae of neotropical species of phlebotomine sand flies (Diptera: Psychodidae under scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Pessoa Felipe Arley Costa

    2001-01-01

    Full Text Available In the present study, some morphological structures of antennae, maxillary palps and caudal setae of fourth instar larvae of laboratory-reared phlebotomine sand flies (Lutzomyia longipalpis, L. migonei, L. evandroi, L. lenti, L. sericea, L. whitmani and L. intermedia of the State of Ceará, Brazil, were examined under scanning electron microscopy. The antennal structures exhibited considerable variation in the morphology and position. A prominent digitiform distal segment has been observed only on the antenna of species of the subgenus Nyssomyia. The taxonomic relevance of this and other antennal structure is discussed. The papiliform structures found in the maxillae and the porous structures of the caudal setae of all species examined may have chemosensory function. Further studies with transmission electron microscopy are needed to better understand the physiological function of these external structures.

  14. Electron energy distribution function in the positive column of a neon glow discharge using the black wall approximation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hawat, Sh; Naddaf, M [Physics Department, Atomic Energy Commission, PO Box 6091, Damascus (Syrian Arab Republic)

    2005-04-21

    The electron energy distribution function (EEDF) was determined from the second derivative of the I-V Langmuir probe characteristics and, thereafter, theoretically calculated by solving the plasma kinetic equation, using the black wall (BW) approximation, in the positive column of a neon glow discharge. The pressure has been varied from 0.5 to 4 Torr and the current from 10 to 30 mA. The measured electron temperature, density and electric field strength were used as input data for solving the kinetic equation. Comparisons were made between the EEDFs obtained from experiment, the BW approach, the Maxwellian distribution and the Rutcher solution of the kinetic equation in the elastic energy range. The best conditions for the BW approach are found to be under the discharge conditions: current density j{sub d} = 4.45 mA cm{sup -2} and normalized electric field strength E/p = 1.88 V cm{sup -1} Torr{sup -1}.

  15. Sequential Subterranean Transport of Excavated Sand and Foraged Seeds in Nests of the Harvester Ant, Pogonomyrmex badius.

    Directory of Open Access Journals (Sweden)

    Walter R Tschinkel

    Full Text Available During their approximately annual nest relocations, Florida harvester ants (Pogonomyrmex badius excavate large and architecturally-distinct subterranean nests. Aspects of this process were studied by planting a harvester ant colony in the field in a soil column composed of layers of 12 different colors of sand. Quantifying the colors of excavated sand dumped on the surface by the ants revealed the progress of nest deepening to 2 m and enlargement to 8 L in volume. Most of the excavation was completed within about 2 weeks, but the nest was doubled in volume after a winter lull. After 7 months, we excavated the nest and mapped its structure, revealing colored sand deposited in non-host colored layers, especially in the upper 30 to 40 cm of the nest. In all, about 2.5% of the excavated sediment was deposited below ground, a fact of importance to sediment dating by optically-stimulated luminescence (OSL. Upward transport of excavated sand is carried out in stages, probably by different groups of ants, through deposition, re-transport, incorporation into the nest walls and floors and remobilization from these. This results in considerable mixing of sand from different depths, as indicated in the multiple sand colors even within single sand pellets brought to the surface. Just as sand is transported upward by stages, incoming seeds are transported downward to seed chambers. Foragers collect seeds and deposit them only in the topmost nest chambers from which a separate group of workers rapidly transports them downward in increments detectable as a "wave" of seeds that eventually ends in the seed chambers, 20 to 80 cm below the surface. The upward and downward transport is an example of task-partitioning in a series-parallel organization of work carried out by a highly redundant work force in which each worker usually completes only part of a multi-step process.

  16. Assembly for connecting the column ends of two capillary columns

    International Nuclear Information System (INIS)

    Kolb, B.; Auer, M.; Pospisil, P.

    1984-01-01

    In gas chromatography, the column ends of two capillary columns are inserted into a straight capillary from both sides forming annular gaps. The capillary is located in a tee out of which the capillary columns are sealingly guided, and to which carrier gas is supplied by means of a flushing flow conduit. A ''straight-forward operation'' having capillary columns connected in series and a ''flush-back operation'' are possible. The dead volume between the capillary columns can be kept small

  17. Compressive behavior of fine sand.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Bradley E. (Air Force Research Laboratory, Eglin, FL); Kabir, Md. E. (Purdue University, West Lafayette, IN); Song, Bo; Chen, Wayne (Purdue University, West Lafayette, IN)

    2010-04-01

    The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.

  18. Transport of 152Eu colloids in a system of fine sand and water containing humic substances

    International Nuclear Information System (INIS)

    Klotz, D.

    1995-01-01

    The migration of 152 Eu in a system of fine sand and water containing humic substances was investigated in a flow column system under realistic conditions. In this system, the trivalent Eu forms colloids with the water. These Eu humates are transported without retardation at recovery rates significantly below 100 per cent. Recovery is more or less a measure of the physical process of filtration of Eu bonded to particulates. In the range of natural filtering rates, the recovery rates decrease with decreasing filtering rate. (orig.) [de

  19. On Pluvial Compaction of Sand

    DEFF Research Database (Denmark)

    Jacobsen, Moust

    At the Institute of Civil Engineering in Aalborg model tests on dry sand specimens have been carried out during the last five years. To reduce deviations in test results, the sand laying technique has been carefully studied, and the sand mass spreader constructed. Preliminary results have been...

  20. MORPHOMETRIC CHARACTERIZATION OF THE SAND FRACTION IN A SAND GRAIN IMAGE CAPTURE SYSTEM1

    Directory of Open Access Journals (Sweden)

    Lucimar Arruda Viana

    Full Text Available ABSTRACT Morphology studies assume significant importance in analysis of phenomena of granular systems packaging, in particular with a view to the use of the technique of soil stabilization named particle size correction in forest roads. In this context, this study aimed to develop and operationalize a Sand Grain Image Capture System and, hereby, determine the morphological indices of the sand fractions of two sandy soils called João Pinheiro (JP and Cachoeira da Prata (CP. Soil samples, air-dried, were sieved (2.0 mm nominal mesh size for removal of gravels. The materials that passed through the sieve were subjected to dispersion, washing in 0.053 mm nominal mesh size sieve, removal of organic matter and iron oxides to obtain the clean sand fractions. Subsequently, each soil sample was sieved for separation into twelve classes, between the diameters of 0.149 mm and 1.190 mm, using a Rotap shaker. Next, tests were carried out to characterize the morphometric attributes of the twelve classes of sand fractions of the soils studied. For validation of the performance of the Sand Grain Image Capture System, the results were compared to those obtained using a standard procedure for image analysis. The analysis of the results led to the following conclusions: (i the sand fraction of the JP soil presented higher values for the morphometric indices roundness, elongation and compactness compared to sand fraction of the CP soil; and (ii the Sand Grain Image Capture System worked properly, with practicality.

  1. Technology unlocks tar sands energy

    Energy Technology Data Exchange (ETDEWEB)

    Law, C

    1967-09-25

    Tar sand processing technology has been developed primarily in the categories of extraction techniques and in-situ processing. In October, a $235 million venture into tar sand processing will be inspected by visitors from many points on the globe. A synthetic crude of premium quality will be flowing through a 16-in. pipeline from the Tar Island plant site of Great Canadian Oil Sands to Edmonton. This processing plant uses an extractive mining technique. The tar sand pay zone in this area averages approximately 150 ft in thickness with a 50-ft overburden. It has been estimated that the tar sands cannot be exploited when the formation thickness is less than 100 ft and overburden exceeds the same amount. This indicates that extraction techniques can only be used to recover approximately 15% of the tar sand deposits. An in-situ recovery technique developed by Shell of Canada is discussed in detail. In essence it is selective hydraulic fracturing, followed by the injection of emulsifying chemicals and steam.

  2. Study of scattering cross section of a plasma column using Green's function volume integral equation method

    Science.gov (United States)

    Soltanmoradi, Elmira; Shokri, Babak

    2017-05-01

    In this article, the electromagnetic wave scattering from plasma columns with inhomogeneous electron density distribution is studied by the Green's function volume integral equation method. Due to the ready production of such plasmas in the laboratories and their practical application in various technological fields, this study tries to find the effects of plasma parameters such as the electron density, radius, and pressure on the scattering cross-section of a plasma column. Moreover, the incident wave frequency influence of the scattering pattern is demonstrated. Furthermore, the scattering cross-section of a plasma column with an inhomogeneous collision frequency profile is calculated and the effect of this inhomogeneity is discussed first in this article. These results are especially used to determine the appropriate conditions for radar cross-section reduction purposes. It is shown that the radar cross-section of a plasma column reduces more for a larger collision frequency, for a relatively lower plasma frequency, and also for a smaller radius. Furthermore, it is found that the effect of the electron density on the scattering cross-section is more obvious in comparison with the effect of other plasma parameters. Also, the plasma column with homogenous collision frequency can be used as a better shielding in contrast to its inhomogeneous counterpart.

  3. Bituminous sands : tax issues

    International Nuclear Information System (INIS)

    Patel, B.

    2004-01-01

    This paper examined some of the tax issues associated with the production of bitumen or synthetic crude oil from oil sands. The oil sands deposits in Alberta are gaining more attention as the supplies of conventional oil in Canada decline. The oil sands reserves located in the Athabasca, Cold Lake and Peace River areas contain about 2.5 trillion barrels of highly viscous hydrocarbons called bitumen, of which nearly 315 billion barrels are recoverable with current technology. The extraction method varies for each geographic area, and even within zones and reservoirs. The two most common extraction methods are surface mining and in-situ extraction such as cyclic steam stimulation (CSS); low pressure steam flood; pressure cycle steam drive; steam assisted gravity drainage (SAGD); hot water flooding; and, fire flood. This paper also discussed the following general tax issues: bituminous sands definition; bituminous sands leases and Canadian development expense versus Canadian oil and gas property expense (COGPE); Canadian exploration expense (CEE) for surface mining versus in-situ methods; additional capital cost allowance; and, scientific research and experimental development (SR and ED). 15 refs

  4. Oil sands tax expenditures

    International Nuclear Information System (INIS)

    Ketchum, K; Lavigne, R.; Plummer, R.

    2001-01-01

    The oil sands are a strategic Canadian resource for which federal and provincial governments provide financial incentives to develop and exploit. This report describes the Oil Sands Tax Expenditure Model (OSTEM) developed to estimate the size of the federal income tax expenditure attributed to the oil sands industry. Tax expenditures are tax concessions which are used as alternatives to direct government spending for achieving government policy objectives. The OSTEM was developed within the business Income Tax Division of Canada's Department of Finance. Data inputs for the model were obtained from oil sands developers and Natural Resources Canada. OSTEM calculates annual revenues, royalties and federal taxes at project levels using project-level projections of capital investment, operating expenses and production. OSTEM calculates tax expenditures by comparing taxes paid under different tax regimes. The model also estimates the foregone revenue as a percentage of capital investment. Total tax expenditures associated with investment in the oil sands are projected to total $820 million for the period from 1986 to 2030, representing 4.6 per cent of the total investment. 10 refs., 2 tabs., 7 figs

  5. Spatial variation in deposition rate coefficients of an adhesion-deficient bacterial strain in quartz sand.

    Science.gov (United States)

    Tong, Meiping; Camesano, Terri A; Johnson, William P

    2005-05-15

    The transport of bacterial strain DA001 was examined in packed quartz sand under a variety of environmentally relevant ionic strength and flow conditions. Under all conditions, the retained bacterial concentrations decreased with distance from the column inlet at a rate that was faster than loglinear, indicating that the deposition rate coefficient decreased with increasing transport distance. The hyperexponential retained profile contrasted againstthe nonmonotonic retained profiles that had been previously observed for this same bacterial strain in glass bead porous media, demonstrating that the form of deviation from log-linear behavior is highly sensitive to system conditions. The deposition rate constants in quartz sand were orders of magnitude below those expected from filtration theory, even in the absence of electrostatic energy barriers. The degree of hyperexponential deviation of the retained profiles from loglinear behavior did not decrease with increasing ionic strength in quartz sand. These observations demonstrate thatthe observed low adhesion and deviation from log-linear behavior was not driven by electrostatic repulsion. Measurements of the interaction forces between DA001 cells and the silicon nitride tip of an atomic force microscope (AFM) showed that the bacterium possesses surface polymers with an average equilibrium length of 59.8 nm. AFM adhesion force measurements revealed low adhesion affinities between silicon nitride and DA001 polymers with approximately 95% of adhesion forces having magnitudes responsible for the low adhesion to silicon nitride, indicating that steric interactions from extracellular polymers controlled DA001 adhesion deficiency and deviation from log-linear behavior on quartz sand.

  6. Contributions to reversed-phase column selectivity: III. Column hydrogen-bond basicity.

    Science.gov (United States)

    Carr, P W; Dolan, J W; Dorsey, J G; Snyder, L R; Kirkland, J J

    2015-05-22

    Column selectivity in reversed-phase chromatography (RPC) can be described in terms of the hydrophobic-subtraction model, which recognizes five solute-column interactions that together determine solute retention and column selectivity: hydrophobic, steric, hydrogen bonding of an acceptor solute (i.e., a hydrogen-bond base) by a stationary-phase donor group (i.e., a silanol), hydrogen bonding of a donor solute (e.g., a carboxylic acid) by a stationary-phase acceptor group, and ionic. Of these five interactions, hydrogen bonding between donor solutes (acids) and stationary-phase acceptor groups is the least well understood; the present study aims at resolving this uncertainty, so far as possible. Previous work suggests that there are three distinct stationary-phase sites for hydrogen-bond interaction with carboxylic acids, which we will refer to as column basicity I, II, and III. All RPC columns exhibit a selective retention of carboxylic acids (column basicity I) in varying degree. This now appears to involve an interaction of the solute with a pair of vicinal silanols in the stationary phase. For some type-A columns, an additional basic site (column basicity II) is similar to that for column basicity I in primarily affecting the retention of carboxylic acids. The latter site appears to be associated with metal contamination of the silica. Finally, for embedded-polar-group (EPG) columns, the polar group can serve as a proton acceptor (column basicity III) for acids, phenols, and other donor solutes. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Singing Sand Dunes

    Indian Academy of Sciences (India)

    ble low-frequency (s. 75–105 Hz), that can some- times be heard up to 10 km away. Scientific in- vestigations suggest that the sustained low fre- quency sound of sand dunes that resembles a pure note from a musical instrument, is due to the synchronized motion of well-sorted dry sand grains when they spontaneously ...

  8. JCE Feature Columns

    Science.gov (United States)

    Holmes, Jon L.

    1999-05-01

    The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using these links you can easily find abstracts of additional articles that are related by topic. Of course, JCE Online+ subscribers are then just one click away from the entire article. Finding related articles is easy because each feature column "site" contains links to the online abstracts of all the articles that have appeared in the column. In addition, you can find the mission statement for the column and the email link to the column editor that I mentioned above. At the discretion of its editor, a feature column site may contain additional resources. As an example, the Chemical Information Instructor column edited by Arleen Somerville will have a periodically updated bibliography of resources for teaching and using chemical information. Due to the increase in the number of these resources available on the WWW, it only makes sense to publish this information online so that you can get to these resources with a simple click of the mouse. We expect that there will soon be additional information and resources at several other feature column sites. Following in the footsteps of the Chemical Information Instructor, up-to-date bibliographies and links to related online resources can be made available. We hope to extend the online component of our feature columns with moderated online discussion forums. If you have a suggestion for an online resource you would like to see included, let the feature editor or JCE Online (jceonline@chem.wisc.edu) know about it. JCE Internet Features JCE Internet also has several feature columns: Chemical Education Resource Shelf, Conceptual Questions and Challenge Problems, Equipment Buyers Guide, Hal's Picks, Mathcad

  9. Characteristics of an elongated plasma column produced by magnetically coupled hollow cathode plasma source

    Science.gov (United States)

    Bhuva, M. P.; Karkari, S. K.; Kumar, Sunil

    2018-03-01

    An elongated plasma column in the presence of an axial magnetic field has been formed using a cylindrical hollow cathode (HC) and a constricted anode (CA). The plasma characteristics of the central line have been found to vary with the magnetic field strength and the axial distance from the source. It is believed that the primary electrons constituting the discharge current are steered by the axial magnetic field to undertake ionizing collisions along the plasma column. The current carrying electrons from the HC reach the anode by cross-field diffusion towards the central line. The above observation has been substantiated using a phenomenological model which links the observed characteristics of the source with the plasma column. The experimental results are found to be in qualitative agreement with the model.

  10. Radiogenic heavy minerals in Brazilian beach sand

    International Nuclear Information System (INIS)

    Malanca, A.

    1998-01-01

    Sand samples collected on the beaches of the 'radioactive' Brazilian town of Guarapari were first separated by flotation in bromoform and successively divided into various magnetic fractions with a Franz isodynamic separator. concentrations of background radionuclides in samples of monazite, ilmenite, and zircon were determined by a γ-ray spectrometer. Chemical composition of monazite, ilmenite and magnetite were assessed by means of an electron microprobe. Monazite resulted to be relatively rich in ThO 2 whose abundance ranged from 5.3 to 7.7 (wt%). (author)

  11. Dosimetric properties of commercial glasses and sand for high doses

    International Nuclear Information System (INIS)

    Teixeira, Maria Ines

    2004-01-01

    Commercial glasses (transparent and colored) produced by Cebrace, Brazil, Sao Paulo, and sand samples of different Brazilian beaches were studied, due to their low cost and easy handling, to verify the possibility of their use in high dose dosimetry. The main dosimetric characteristics were determined using a densitometer, a spectrophotometer, a thermoluminescent (TL) reader and an electronic paramagnetic resonance system. The gamma irradiations were carried out using a Gamma-Cell 220 and a panoramic source ( 60 Co) of IPEN. An optical absorption band was observed at 420 nm in the glass samples. The TL glow curves presented peaks at 205 deg C, 135 deg C, 150 deg C and 145 deg C for the transparent, bronze, brown and green glass samples, respectively. All EPR spectra of the glasses showed Fe 3+ characteristic signals at g = 4.27 and 2.01. The gamma irradiated sand samples presented two peaks at 110 deg C and 170 deg C and an EPR signal at g= 1.999. However, these materials present a pronounced thermal fading at room temperature after irradiation. With the objective to minimize this thermal fading, both glass and sand samples were submitted to different pre- and post-irradiation thermal treatments. The glass and sand samples showed the possibility of utilization for high dose dosimetry and as Yes/No irradiation detectors. (author)

  12. Column studies of strontium and cesium migration in a granular geologic material

    International Nuclear Information System (INIS)

    Reynolds, W.D.; Gilham, R.W.; Cherry, J.A.

    1981-06-01

    Infinite-pulse, miscible-displacement experiments were conducted to investigate the applicability of batch Ksub(d) values in the prediction of reactive solute transport during dynamic flow through porous media. Non-reactive tracers (chloride, tritium and oxygen-18), and the reactive tracers (strontium-85 and cesium-137) were passed through a column 5.0 cm long and 6.5 cm in diameter packed with a medium to fine sand. The effluent concentrations of the nonreactive solutes were accurately predicted using the advection-dispersion equation; however, there were large discrepancies between the measured and predicted effluent concentrations for both reactive species. Good agreement was obtained between the measured and computed results by incorporating an empirical isotherm into the advection-dispersion model

  13. Radon diffusion studies in air, gravel, sand, soil and water

    International Nuclear Information System (INIS)

    Singh, B.; Singh, S.; Virk, H.S.

    1993-01-01

    Radon isotopes are practically inert and have properties of gases under conditions of geological interest. During their brief lives their atoms are capable of moving from sites of their generation. Radon diffusion studies were carried out in air, gravel, sand, soil and water using silicon diffused junction electronic detector, Alphameter-400. Diffusion constant and diffusion length is calculated for all these materials. (author)

  14. Simultaneous Scanning Electron Microscope Imaging of Topographical and Chemical Contrast Using In-Lens, In-Column, and Everhart-Thornley Detector Systems.

    Science.gov (United States)

    Zhang, Xinming; Cen, Xi; Ravichandran, Rijuta; Hughes, Lauren A; van Benthem, Klaus

    2016-06-01

    The scanning electron microscope provides a platform for subnanometer resolution characterization of material morphology with excellent topographic and chemical contrast dependent on the used detectors. For imaging applications, the predominantly utilized signals are secondary electrons (SEs) and backscattered electrons (BSEs) that are emitted from the sample surface. Recent advances in detector technology beyond the traditional Everhart-Thornley geometry have enabled the simultaneous acquisition and discrimination of SE and BSE signals. This study demonstrates the imaging capabilities of a recently introduced new detector system that consists of the combination of two in-lens (I-L) detectors and one in-column (I-C) detector. Coupled with biasing the sample stage to reduce electron-specimen interaction volumes, this trinity of detector geometry allows simultaneous acquisition of signals to distinguish chemical contrast from topographical changes of the sample, including the identification of surface contamination. The I-C detector provides 4× improved topography, whereas the I-L detector closest to the sample offers excellent simultaneous chemical contrast imaging while not limiting the minimization of working distance to obtain optimal lateral resolution. Imaging capabilities and contrast mechanisms for all three detectors are discussed quantitatively in direct comparison to each other and the conventional Everhart-Thornley detector.

  15. Temperature-based on-column solute focusing in capillary liquid chromatography reduces peak broadening from pre-column dispersion and volume overload when used alone or with solvent-based focusing.

    Science.gov (United States)

    Groskreutz, Stephen R; Horner, Anthony R; Weber, Stephen G

    2015-07-31

    On-column focusing is essential for satisfactory performance using capillary scale columns. On-column focusing results from generating transient conditions at the head of the column that lead to high solute retention. Solvent-based on-column focusing is a well-known approach to achieve this. Temperature-assisted on-column focusing (TASF) can also be effective. TASF improves focusing by cooling a short segment of the column inlet to a temperature that is lower than the column temperature during the injection and then rapidly heating the focusing segment to the match the column temperature. A troublesome feature of an earlier implementation of TASF was the need to leave the capillary column unpacked in that portion of the column inside the fitting connecting it to the injection valve. We have overcome that problem in this work by packing the head of the column with solid silica spheres. In addition, technical improvements to the TASF instrumentation include: selection of a more powerful thermo-electric cooler to create faster temperature changes and electronic control for easy incorporation into conventional capillary instruments. Used in conjunction with solvent-based focusing and with isocratic elution, volumes of paraben samples (esters of p-hydroxybenzoic acid) up to 4.5-times the column liquid volume can be injected without significant bandspreading due to volume overload. Interestingly, the shapes of the peaks from the lowest volume injections that we can make, 30nL, are improved when using TASF. TASF is very effective at reducing the detrimental effects of pre-column dispersion using isocratic elution. Finally, we show that TASF can be used to focus the neuropeptide galanin in a sample solvent with elution strength stronger than the mobile phase. Here, the stronger solvent is necessitated by the need to prevent peptide adsorption prior to and during analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. The jammed-to-mobile transition in frozen sand under stress

    Science.gov (United States)

    Durham, W. B.; Pathare, A.; Stern, L. A.; Lenferink, H. J.

    2009-12-01

    We conducted laboratory deformation experiments on sand-rich mixtures of sand + ice under sufficient confinement to inhibit macroscopic dilation. Dry sand packs constrained not to dilate when they are under a shearing load reach an immobile or “jammed” state, as load-supporting “force chains” of sand particles form after a small amount of strain and cannot be broken without volume expansion. Our research objective here was to find the minimum volume fraction of ice required to overcome the jammed state. The result surprised us: the required volume fraction is not a fixed number, but depends on the packing characteristics of the sand in question. Experiments were carried out in a triaxial gas deformation rig at confining pressures (60 - 200 MPa) always at least twice the level of differential stresses (11 - 50 MPa) in order to suppress dilatancy. Run temperatures were 223 - 243 K. We used two kinds of quartz sand, one well-sorted, with a maximum dry packing density (MDPD) of about 0.68 sand by volume, and the other a mixture of two sizes, having a higher MDPD of 0.75. Ice volume fraction ranged from well below saturation (where unfilled porosity necessarily remained) to slightly greater than the value of porosity at MDPD. We tested these frozen sands in compression under constant applied differential stress (creep). Strain rates were very low at these conditions, and runs took days or weeks to complete. The amount of strain required to reach the jammed state in ice-undersaturated samples was approximately 0.04, and did not show an obvious dependence on ice content. For both sands, the onset of mobility occurred at approximately 5% above the value of pore volume at MDPD. Furthermore, viscosity of mobile frozen sand near the transition point was extremely sensitive to ice fraction, which implies that at geologic strain rates, far slower than we can reach in the lab, the ice fraction at transition may lie closer to that at MDPD. Cryogenic scanning electron

  17. Column Liquid Chromatography.

    Science.gov (United States)

    Majors, Ronald E.; And Others

    1984-01-01

    Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

  18. Field test on sand compaction pile method with copper slag sand; Dosuisai slag wo mochiita SCP koho no shiken seko

    Energy Technology Data Exchange (ETDEWEB)

    Minami, K.; Matsui, H.; Naruse, E.; Kitazume, M. [Port and Harbour Research Inst., Kanagawa (Japan)

    1997-09-20

    This paper describes the sand compaction pile (SCP) method using copper slag sand. The SCP method is a method by which sand compaction piles are constructed in the ground, and improvement can be obtained in a short period. This method has been widely used even in the port areas for enhancing the bearing power of soft clay ground and the lateral resistance of sheet pile. A great deal of sand is required as a material. The sand requires high permeability, proper size distribution with less fine particle fraction content, easy compaction property with enough strength, and easy discharging property from the casing of construction machines as required properties. Recently, it becomes hard to secure proper sand materials. The copper slag sand is obtained from refining process of copper as a by-product which is quenched in water flow and crushed in water. The copper slag sand has higher particle density than that of sand, excellent permeability, and similar size distribution to that of sand. From compaction drainage triaxial compression test and permeability test, it was found that the mechanical properties of copper slag sand did not change by the crushing of grains with keeping excellent permeability. Through the test construction, applicability of the copper slag sand to the SCP method could be confirmed as an alternate material of sand. 17 refs., 9 figs., 4 tabs.

  19. Flow and suspended-sand behavior in large rivers after dredging.

    Science.gov (United States)

    Yuill, B. T.; Wang, Y.; Allison, M. A.; Meselhe, E. A.

    2017-12-01

    Dredging is commonly used in large rivers to promote navigation and provide sediment for engineering projects. Channel bars typically have thicker, coarser sediment deposits than elsewhere on the channel bed and are often the focus of dredging projects. Bar dredging may create deep pits ("borrow pits") that significantly alter flow and sediment transport. Locally, the pit acts as a large bedform, contracting and expanding the flow field and enhancing turbulence. At the reach scale, the pit acts as a new sediment sink and disrupts the sediment budget which may have consequences for channel stability and aquatic ecosystem health. In this study, we focus on the local impact of the borrow pit and how it, similar to dunes, creates a turbulent wake within the downstream flow column. We hypothesize that this wake may have implications for the overlapping suspended-sediment transport fields. Efficient dredging operations requires the ability to predict channel infilling/recovery timescales and in large, sandy rivers, a substantial fraction of the sediment infilling results from the settling of suspended sediment. However, if the turbulent wake significantly alters pathways of sediment settling within the borrow pit, typical models of sediment deposition that do not account for the wake effects may not apply. To explore this problem, we use numerical modelling to predict sand behavior with and without resolving the effects of wake turbulence. Wake turbulence is resolved using detached-eddy simulation and sand settling is simulated using Lagrangian particle tracking. Our study area is a >1 km2 channel bar in the lower Mississippi River, which was dredged in October 2016. We used vessel-based measurements (MBES, ADCP) to characterize the post-dredge hydrodynamic environment. Study results indicate that the turbulent wake significantly impacted suspended-sand behavior as it entered the borrow pit and large eddies increased the vertical grain velocities, mean grain settling was

  20. A mechanistic study of the uniform corrosion of copper in compacted clay-sand soil

    International Nuclear Information System (INIS)

    Litke, C.D.; Ryan, S.R.; King, F.

    1992-08-01

    The results of a study of the mechanism of uniform corrosion of copper under simulated nuclear fuel waste disposal conditions are presented. Evidence is given that suggests that the rate-controlling process is the transport of copper corrosion products away from the corroding surface. In the experiments described here, the copper diffused through a column of compacted clay-sand buffer. The properties of the buffer material, especially its ability to sorb copper species, are significant in determining the rate of uniform corrosion of copper. The evidence that copper diffusion is rate-controlling stems from the effect of γ-radiation on the tests. In the presence of γ-radiation, copper diffused farther along the column of compacted buffer material than in the unirradiated tests, but the corrosion rate was lower. These two effects can be best explained in terms of a slow copper-diffusion process. Irradiation is thought to reduce the extent of sorption of copper by the clay component of the buffer. This results in a more mobile copper species and a smaller interfacial flux of copper (i.e., a lower corrosion rate)

  1. Galveston Island, Texas, Sand Management Strategies

    Science.gov (United States)

    2016-07-01

    billion m3 of beach quality sand . However, Texas projects to date have not utilized these sources because of transportation costs. The lack of nearby...estimate that the San Luis Pass flood shoal contains approximately 11.8 million yd3 of beach quality sand . However, it is expected that if permits...a source of beach- quality sand . 2. Sand could be intercepted before it reaches the present dry beach. ERDC/CHL TR-16-13 55 3. The volume of

  2. Inhalation exposure during spray application and subsequent sanding of a wood sealant containing zinc oxide nanoparticles.

    Science.gov (United States)

    Cooper, Michael R; West, Gavin H; Burrelli, Leonard G; Dresser, Daniel; Griffin, Kelsey N; Segrave, Alan M; Perrenoud, Jon; Lippy, Bruce E

    2017-07-01

    Nano-enabled construction products have entered into commerce. There are concerns about the safety of manufactured nanomaterials, and exposure assessments are needed for a more complete understanding of risk. This study assessed potential inhalation exposure to ZnO nanoparticles during spray application and power sanding of a commercially available wood sealant and evaluated the effectiveness of local exhaust ventilation in reducing exposure. A tradesperson performed the spraying and sanding inside an environmentally-controlled chamber. Dust control methods during sanding were compared. Filter-based sampling, electron microscopy, and real-time particle counters provided measures of exposure. Airborne nanoparticles above background levels were detected by particle counters for all exposure scenarios. Nanoparticle number concentrations and particle size distributions were similar for sanding of treated versus untreated wood. Very few unbound nanoparticles were detected in aerosol samples via electron microscopy, rather nano-sized ZnO was contained within, or on the surface of larger airborne particles. Whether the presence of nanoscale ZnO in these aerosols affects toxicity merits further investigation. Mass-based exposure measurements were below the NIOSH Recommended Exposure Limit for Zn, although there are no established exposure limits for nanoscale ZnO. Local exhaust ventilation was effective, reducing airborne nanoparticle number concentrations by up to 92% and reducing personal exposure to total dust by at least 80% in terms of mass. Given the discrepancies between the particle count data and electron microscopy observations, the chemical identity of the airborne nanoparticles detected by the particle counters remains uncertain. Prior studies attributed the main source of nanoparticle emissions during sanding to copper nanoparticles generated from electric sander motors. Potentially contrary results are presented suggesting the sander motor may not have been

  3. Numerical simulation of aeolian sand ripples

    International Nuclear Information System (INIS)

    Kang Liqiang; Guo Liejin

    2004-01-01

    With a new horizontal saltation displacement vector, a model is implemented to simulate the initiation and evolution of aeolian sand ripples. In the model, saltation distance considers the effects of surface height and slope. A linear stability analysis is also carried out for formation of sand ripples. The results show that, the model can be able to successfully reproduce sand ripples which can increase in scale by merging of small ripples. The linear stability analysis indicates that sand ripples appear when the relaxation rate parameter is below a threshold value and wind strength parameter is larger than a critical value. The results also verified that the formation of sand ripples is a self-organization process

  4. Japan's involvement in oil sands development

    International Nuclear Information System (INIS)

    Sugiura, T.

    1994-01-01

    According to Japanese national policy, exploration and development by Japanese companies in overseas countries are promoted in order to ensure stable oil supplies. Japan Canada Oil Sands Limited (JACOS), part of the JAPEX group, was established during the 1978 world oil crisis to explore and develop Canadian oil sand resources in accordance with Japan's national policy. The JAPEX group, including JACOS, has invested $123 million in oil sands projects in Alberta. JAPEX's first involvement in oil sands was in the Primrose Project operated by Norcen in the Cold Lake area. Five years of cyclic steam stimulation pilot tests did not produce sufficiently good results to justify further operation. The second involvement was the PCEJ Project, a joint effort by four companies that are participating in a bitumen recovery test project in the Athabasca Deposit. JACOS holds 2,452 km 2 of oil sands leases in Alberta. Tests conducted since 1978 in the PCEJ Project include multiwell steam injection pilot tests, some of which showed promise. JACOS is also participating in steam assisted gravity drainage projects and in federal/provincial research programs. Obstacles identified in developing Alberta oil sands are the lack of a bitumen pipeline to Edmonton and the insufficient length of oil sands leases (currently 10 years), given the difficulties of oil sand development. 10 figs

  5. Chromatographic studies of thorium(IV) and its extraction from monazite sand

    International Nuclear Information System (INIS)

    Bandyopadhyay, Arup; Roy, Uday Sankar

    1998-01-01

    A simple, rapid and selective method has been developed for reversed phase extraction chromatographic studies of Th IV with high molecular mass monocarboxylic acid (C 15 -C 16 ), SRS-100 as a stationary phase on a column of silica gel. Quantitative extraction of Th IV has been achieved in the pH range 4.8-5.5. The extracted Th IV has been stripped with 1:1 (v/v) mixture of 0.2 M HNO 3 and 0.2 M NaNO 3 and estimated spectrophotometrically. The effect of variables as pH, stripping agents, flow rate on extraction and elution have been studied. Th IV has been separated from various commonly associated elements in binary and synthetic multicomponent mixtures. The method has been applied successfully for the extraction of thorium from monazite sand. (author)

  6. MouldingSandDB – a modern database storing moulding sands properties research results

    Directory of Open Access Journals (Sweden)

    J. Jakubski

    2011-01-01

    Full Text Available The complexity of foundry processes requires the use of modern, advanced IT tools for optimization, storage and analysis of t echnicaldata. Properties of moulding and core sands that are collected in research laboratories, manufacturers, and finally in the foundries, are not in use later on. It seems important to create a database that will allow to use the results stored, along with the possibility of searching according to set criteria, adjusted to casting practice. This paper presents part of the database named „MouldingSandDB”, which allows to collect and search data for synthetic moulding sands.

  7. Investigating geochemical aspects of managed aquifer recharge by column experiments with alternating desalinated water and groundwater.

    Science.gov (United States)

    Ronen-Eliraz, Gefen; Russak, Amos; Nitzan, Ido; Guttman, Joseph; Kurtzman, Daniel

    2017-01-01

    Managed aquifer recharge (MAR) events are occasionally carried out with surplus desalinated seawater that has been post-treated with CaCO 3 in infiltration ponds overlying the northern part of the Israeli Coastal Aquifer. This water's chemical characteristics differ from those of any other water recharged to the aquifer and of the natural groundwater. As the MAR events are short (hours to weeks), the sediment under the infiltration ponds will intermittently host desalinated and natural groundwater. As part of comprehensive research on the influence of those events, column experiments were designed to simulate the alternation of the two water types: post-treated desalinated seawater (PTDES) and natural groundwater (GW). Each experiment included three stages: (i) saturation with GW; (ii) inflow of PTDES; (iii) inflow of GW. Three runs were conducted, each with different sediments extracted from the field and representing a different layer below the infiltration pond: (i) sand (<1% CaCO 3 ), (ii) sand containing 7% CaCO 3 , and (iii) crushed calcareous sandstone (35% CaCO 3 ). The results from all columns showed enrichment of K + and Mg 2+ (up to 0.4meq/L for 20 pore volumes) when PTDES replaced GW, whereas an opposite trend of Ca 2+ depletion (up to 0.5meq/L) was observed only in the columns that contained a high percentage of CaCO 3 . When GW replaced PTDES, depletion of Mg 2+ and K + was noted. The results indicated that adsorption/desorption of cations are the main processes causing the observed enrichment/depletion. It was concluded that the high concentration of Ca 2+ (relative to the total concentration of cations) and the low concentration of Mg 2+ in the PTDES relative to natural GW are the factors controlling the main sediment-water interaction. The enrichment of PTDES with Mg 2+ may be viewed as an additional post-treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Flow-through Column Experiments and Modeling of Microbially Mediated Cr(VI) Reduction at Hanford 100H

    Science.gov (United States)

    Yang, L.; Molins, S.; Beller, H. R.; Brodie, E. L.; Steefel, C.; Nico, P. S.; Han, R.

    2010-12-01

    Microbially mediated Cr(VI) reduction at the Hanford 100H area was investigated by flow-through column experiments. Three separate experiments were conducted to promote microbial activities associated with denitrification, iron and sulfate reduction, respectively. Replicate columns packed with natural sediments from the site under anaerobic environment were injected with 5mM Lactate as the electron donor and 5 μM Cr(VI) in all experiments. Sulfate and nitrate solutions were added to act as the main electron acceptors in the respective experiments, while iron columns relied on the indigenous sediment iron (and manganese) oxides as electron acceptors. Column effluent solutions were analyzed by IC and ICP-MS to monitor the microbial consumption/conversion of lactate and the associated Cr(VI) reduction. Biogeochemical reactive transport modeling was performed to gain further insights into the reaction mechanisms and Cr(VI) bioreduction rates. All experimental columns showed a reduction of the injected Cr(VI). Columns under denitrifying conditions showed the least Cr(VI) reduction at early stages (simulations indicated that biomass growth completely depleted influent ammonium, and called for an additional source of N to account for the measured reduction rates. Iron columns were the least active with undetectable consumption of the injected lactate, slowest cell growth, and the smallest change in Cr(VI) concentrations during the course of the experiment. In contrast, columns under sulfate-reducing/fermentative conditions exhibited the greatest Cr(VI) reduction capacity. Two sulfate columns evolved to complete lactate fermentation with acetate and propionate produced in the column effluent after 40 days of experiments. These fermenting columns showed a complete removal of injected Cr(VI), visible precipitation of sulfide minerals, and a significant increase in effluent Fe and Mn concentrations. Reactive transport simulations suggested that direct reduction of Cr(VI) by

  9. Computational fluid dynamics simulation of transport and retention of nanoparticle in saturated sand filters

    International Nuclear Information System (INIS)

    Hassan, Ashraf Aly; Li, Zhen; Sahle-Demessie, Endalkachew; Sorial, George A.

    2013-01-01

    Highlights: ► Breakthrough curves used to study fate of NPs in slow sand filters (SSF). ► CFD simulate transport, attachment/detachment of NPs in SSFs. ► CFD predicted spatial and temporal changes for transient concentrations of NPs. ► CFD predicts low concentrations and steady NP influx would not be retained by SSFs. ► Pulse input is retained with outlet concentration of 0.2% of the inlet. -- Abstract: Experimental and computational investigation of the transport parameters of nanoparticles (NPs) flowing through porous media has been made. This work intends to develop a simulation applicable to the transport and retention of NPs in saturated porous media for investigating the effect of process conditions and operating parameters such, as ion strength, and filtration efficiency. Experimental data obtained from tracer and nano-ceria, CeO 2 , breakthrough studies were used to characterize dispersion of nanoparticle with the flow and their interaction with sand packed columns with different heights. Nanoparticle transport and concentration dynamics were solved using the Eulerian computational fluid dynamics (CFD) solver ANSYS/FLUENT ® based on a scaled down flow model. A numerical study using the Navier–Stokes equation with second order interaction terms was used to simulate the process. Parameters were estimated by fitting tracer, experimental NP transport data, and interaction of NP with the sand media. The model considers different concentrations of steady state inflow of NPs and different amounts of spike concentrations. Results suggest that steady state flow of dispersant-coated NPs would not be retained by a sand filter, while spike concentrations could be dampened effectively. Unlike analytical solutions, the CFD allows estimating flow profiles for structures with complex irregular geometry and uneven packing

  10. Computational fluid dynamics simulation of transport and retention of nanoparticle in saturated sand filters

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Ashraf Aly [U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH 45268 (United States); Li, Zhen [School of Energy, Environmental, Biological, and Medical Engineering, Environmental Engineering Program, University of Cincinnati, Cincinnati, OH (United States); Sahle-Demessie, Endalkachew, E-mail: sahle-demessie.endalkachew@epa.gov [U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH 45268 (United States); Sorial, George A. [School of Energy, Environmental, Biological, and Medical Engineering, Environmental Engineering Program, University of Cincinnati, Cincinnati, OH (United States)

    2013-01-15

    Highlights: ► Breakthrough curves used to study fate of NPs in slow sand filters (SSF). ► CFD simulate transport, attachment/detachment of NPs in SSFs. ► CFD predicted spatial and temporal changes for transient concentrations of NPs. ► CFD predicts low concentrations and steady NP influx would not be retained by SSFs. ► Pulse input is retained with outlet concentration of 0.2% of the inlet. -- Abstract: Experimental and computational investigation of the transport parameters of nanoparticles (NPs) flowing through porous media has been made. This work intends to develop a simulation applicable to the transport and retention of NPs in saturated porous media for investigating the effect of process conditions and operating parameters such, as ion strength, and filtration efficiency. Experimental data obtained from tracer and nano-ceria, CeO{sub 2}, breakthrough studies were used to characterize dispersion of nanoparticle with the flow and their interaction with sand packed columns with different heights. Nanoparticle transport and concentration dynamics were solved using the Eulerian computational fluid dynamics (CFD) solver ANSYS/FLUENT{sup ®} based on a scaled down flow model. A numerical study using the Navier–Stokes equation with second order interaction terms was used to simulate the process. Parameters were estimated by fitting tracer, experimental NP transport data, and interaction of NP with the sand media. The model considers different concentrations of steady state inflow of NPs and different amounts of spike concentrations. Results suggest that steady state flow of dispersant-coated NPs would not be retained by a sand filter, while spike concentrations could be dampened effectively. Unlike analytical solutions, the CFD allows estimating flow profiles for structures with complex irregular geometry and uneven packing.

  11. Approximations to the electron energy distribution and positive column models for low-pressure discharge light sources

    International Nuclear Information System (INIS)

    Lister, G G; Sheverev, V A; Uhrlandt, D

    2002-01-01

    The applicability of 'fluid' models based on analytic approximations of the electron energy distribution function (EEDF) and of kinetic models for low-pressure discharge light sources is discussed. Traditionally, 'fluid' models of fluorescent lamps assume that the EEDF is Maxwellian up to the energy of the first excited state. It is shown that such an approach is sufficiently accurate in most cases of conventional as well as of 'highly loaded' fluorescent lamps. However, this assumption is strongly violated for many rare gas glow discharges for mercury free light sources. As an example, a neon dc discharge is studied. The densities of the four lowest excited states and the electric field have been measured. The experimental results can be fairly well reproduced by a kinetic positive column model. This article was scheduled to appear in issue 14 of J. Phys. D: Appl. Phys. To access this special issue please follow this link: http://stacks.iop.org/0022-3727/35/i=14/

  12. Policy Analysis of the Canadian Oil Sands Experience

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2013-09-01

    For those who support U.S. oil sands development, the Canadian oil sands industry is often identified as a model the U.S. might emulate, yielding financial and energy security benefits. For opponents of domestic oil sands development, the Canadian oil sands experience illustrates the risks that opponents of development believe should deter domestic policymakers from incenting U.S. oil sands development. This report does not seek to evaluate the particular underpinnings of either side of this policy argument, but rather attempts to delve into the question of whether the Canadian experience has relevance as a foundational model for U.S. oil sands development. More specifically, this report seeks to assess whether and how the Canadian oil sands experience might be predictive or instructive in the context of fashioning a framework for a U.S. oil sands industry. In evaluating the implications of these underpinnings for a prospective U.S. oil sands industry, this report concentrates on prospective development of the oil sands deposits found in Utah.

  13. A study of global sand seas

    Science.gov (United States)

    McKee, Edwin D.

    1979-01-01

    The birth of the idea that led to this publication on "Global Sand Seas" dates back to the late 1920's. At that time I was engaged in a study of the Coconino Sandstone of Arizona's Grand Canyon. Considerable controversy existed then as to whether this sandstone was a subaqueous deposit or was composed of wind-formed dunes. It became apparent that definitive literature was sparse or lacking on types of dunes, global distribution of these types, the mechanics of their development, the precise nature of their internal structure of cross-stratificiation, and the relation of wind systems to these sand forms. Especially lacking were data on criteria that could confidently be used in the recognition of ancient dunes. The common denominator in this publication is eolian sand bodies. Although the book is concerned primarily with desert sand seas, the subject matter is not restricted to deserts; it includes many references to deposits of coastal sand and to sand bodies in humid climates. Nor does the book deal exclusively with dunes, which, according to most definitions, involve mounds or hills. Many references are made to sand sheets, sand stringers, and other types of sand deposits that have no prominent topographic expression. All sand bodies accumulated by the action of wind are discussed. Chapters A-J of this publication are primarily topical. Chapters cover the grain texture, the color, and the structure of modern dunes and other eolian sands. Special treatment is given to the relation of wind data to dune interpretation, the evolution of form in current-deposited sand bodies as determined from experimental studies, and the discriminant analysis technique for differentiating between coastal and inland desert sands. This topical part of the publication also includes an analysis of criteria used in ancient deposits to interpret their eolian genesis and a consideration of economic application of the principles described, including a discussion of potentials and problems

  14. Wear and microstructural characteristics of spray atomized zircon sand reinforced LM13 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, K.; Pandey, O.P. [School of Physics and Materials Science, Thapar University Patiala, Punjab (India)

    2010-07-15

    The requirement of the high performance light weight materials demands the development of varieties of materials within the economical range to get it commercialized. Light weight aluminium alloys are used in several structural applications like automotive, aerospace, defense industry and other fields of engineering. The ceramic particle reinforced aluminium metal matrix composites (AMCs) have emerged as a suitable candidate for commercial applications. A variety of processing routes have been adopted to manufacture AMCs. In the present work LM13 alloy reinforced with zircon sand is formed via spray forming. During experimentation a self prepared convergent-divergent nozzle is used for inert gas atomization of the melt which is subsequently deposited on copper substrate placed vertically below the atomizer. The zircon sand particles are injected in the atomization zone by external injectors aligned perpendicular to the gas atomization axis. Zircon sand has been found to have new promising economical commercial candidate due to its easy availability and good mechanical properties like high hardness, high modulus of elasticity and good thermal stability. The microhardness of cast alloy and spray formed composite shows that the spray formed zircon sand reinforced composite has higher hardness. Also the lower wear rate has been observed in case of the zircon sand reinforced AMC as compared to LM13 alloy. This behaviour is further analyzed in light of microstructural features of the spray deposited composite using optical and scanning electron microscope (SEM). A comparative study of this material (LM13/Zircon sand) with the parent alloy (LM13) is presented in this work. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  15. Synthesis of focusing-and-deflection columns

    International Nuclear Information System (INIS)

    Szilagyi, M.; Mui, P.H.

    1995-01-01

    Szilagyi and Szep have demonstrated that focusing lenses of high performances can be constructed from a column of circular plate electrodes. Later, Szilagyi modified that system to include dipole, quadrupole, and octupole components by partitioning each plate into eight equal sectors. It has already been shown that the additional quadrupole components can indeed bring about substantial improvements in the focusing of charged particle beams. In this article, that design procedure is expanded to construct columns capable of both focusing and deflecting particle beams by just introducing additional dipole components. In this new design, the geometry of the system remains unchanged. The only extra complication is the demand for more individual controls of the sector voltages. Two sample designs, one for negative ions and one for electrons, are presented showing that in both cases a ±2.3 mrad diverging beam can be focused down to a spot of less than 50 nm in radius over a scanning circular area of radius 0.25 mm. The details of the two systems are given in Sec. IV along with the source conditions. The performance of the negative ion system is found to be comparable to the published data. For the relativistic electron system, the interaction of individual components to reduce various aberrations is investigated. copyright 1995 American Vacuum Society

  16. Transport of surface-modified iron nanoparticle in porous media and application to arsenic(III) remediation

    International Nuclear Information System (INIS)

    Kanel, Sushil Raj; Nepal, Dhriti; Manning, Bruce; Choi, Heechul

    2007-01-01

    The surface-modified iron nanoparticles (S-INP) were synthesized, characterized and tested for the remediation of arsenite (As(III)), a well known toxic groundwater contaminant of concern. The S-INP material was fully dispersed in the aqueous phase with a particle size distribution of 2-10 nm estimated from high-resolution transmission electron microscopy (HR-TEM). X-ray photoelectron spectroscopy (XPS) revealed that an Fe(III) oxide surface film was present on S-INP in addition to the bulk zero-valent Fe 0 oxidation state. Transport of S-INP through porous media packed in 10 cm length column showed particle breakthroughs of 22.1, 47.4 and 60 pore volumes in glass beads, unbaked sand, and baked sand, respectively. Un-modified INP was immobile and aggregated on porous media surfaces in the column inlet area. Results using S-INP pretreated 10 cm sand-packed columns containing ∼2 g of S-INP showed that 100 % of As(III) was removed from influent solutions (flow rate 1.8 mL min -1 ) containing 0.2, 0.5 and 1.0 mg L -1 As(III) for 9, 7 and 4 days providing 23.3, 20.7 and 10.4 L of arsenic free water, respectively. In addition, it was found that 100% of As(III) in 0.5 mg/L solution (flow rate 1.8 mL min -1 ) was removed by S-INP pretreated 50 cm sand packed column containing 12 g of S-INP for more than 2.5 months providing 194.4 L of arsenic free water. Field emission scanning electron microscopy (FE-SEM) showed S-INP had transformed to elongated, rod-like shaped corrosion product particles after reaction with As(III) in the presence of sand. These results suggest that S-INP has great potential to be used as a mobile, injectable reactive material for in-situ sandy groundwater aquifer treatment of As(III)

  17. Smart controller based scaler rate-meter for gamma column scanning application

    International Nuclear Information System (INIS)

    Narender Reddy, J.; Dhanajay Reddy, Y.; Dheeraj Reddy, J.

    2001-01-01

    A smart, controller based Scaler Rate-meter with scintillation probe for Gamma column scanning has been developed and made available. Designed to have advanced features with state-of-art electronic devices, hardware features include built-in adj. HV, amplifier- SCA, controller based data acquisition card, LCD display module for visualization of, HV set, preset and elapsed times, counts/count rate, column height and other programmable parameters. User interface is through a built-in programmable key pad, for instrument control, data acquisition, storage. Powerful embedded software provides all the above functions. Unit has capability to store up to 5000 readings. Data readings stored can be downloaded into a PC/lap top to generate a plot of count rate Vs column height, which is a signature for the column under study. Scintillation Probe design facilitates connection to the main unit through a single cable, permitting lengths up to 30 meters from the main unit. (author)

  18. Numerical simulation of wind-sand movement in the reversed flow region of a sand dune with a bridge built downstream.

    Science.gov (United States)

    He, Wei; Huang, Ning; Xu, Bin; Wang, Wenbo

    2018-04-23

    A bridge built inside the reversed flow region of a sand dune will change the characteristics of wind-sand movement in this region. The Reynolds-averaged Navier-Stokes simulation and discrete particle tracing are used to simulate the wind-sand movement around a sand dune with a bridge built inside the reversed region. Three cases with different bridge positions are studied. The results show that 1) compared with the isolated dune case, a tall bridge built at the leeward toe leads to an increase in the deposition rate on the leeward slope and a longer reversed flow region downstream of the sand dune; meanwhile, the high speed of crosswind on the bridge indicates that some measures should be taken to protect trains from strong crosswind; 2) a low bridge at the leeward toe has little effect on the sand deposition and reversed flow region of the dune; however, low sand transport rate and crosswind speed on the bridge show that anti-crosswind/sand measures should be taken according to the actual situation and 3) a low bridge on the leeward slope has little effect on the length of reversed flow region, however, high crosswind speed and sand flux on the bridge reveal the need of anti-crosswind/sand measures on the bridge. Moreover, the bridges in the reversed flow region increase the sand flux near the leeward crest; as a result, the moving patterns of the sand dune are changed.

  19. Sand dune tracking from satellite laser altimetry

    Science.gov (United States)

    Dabboor, Mohammed

    Substantial problems arise from sand movement in arid and semi-arid countries. Sand poses a threat to infrastructure, agricultural and urban areas. These issues are caused by the encroachment of sand on roads and railway tracks, farmland, towns and villages, and airports, to name a few. Sand movement highly depends on geomorphology including vegetation cover, shape and height of the terrain, and grain size of the sand. However, wind direction and speed are the most important factors that affect efficient sand movement. The direction of the movement depends on the main direction of the wind, but it has been shown that a minimum wind speed is required, e.g. wind gusts, to initiate sand transport. This fact prevents a simple calculation of sand transport from conventional wind data as wind records rarely contain sub-minute intervals masking out any wind gusts. An alternative of predicting sand transport is the direct observation of sand advance by in situ measurements or via satellite. Until recently, satellite imagery was the only means to compare dune shape and position for predicting dune migration over several years. In 2003, the NASA laser altimetry mission ICESat became operational and monitors elevations over all surface types including sand dunes with an accuracy of about 10-20 cm. In this study, ICESat observations from repeat tracks (tracks overlapping eachother within 50 m) are used to derive sand dune advance and direction. The method employs a correlation of the elevation profiles over several dunes and was sucessfully validated with synthetic data. The accuracy of this method is 5 meters of dune advance. One of the most active areas exhibiting sand and dune movement is the area of the Arabian Peninsula. Approximately one-third of the Arabian Peninsula is covered by sand dunes. Different wind regimes (Shamal, Kaus) cause sand dune movement in the selected study area in the eastern part of the Arabian Peninsula between 20-25 degrees North and 45-55 degrees

  20. Comparison of lactate, formate, and propionate as hydrogen donors for the reductive dehalogenation of trichloroethene in a continuous-flow column

    Science.gov (United States)

    Azizian, Mohammad F.; Marshall, Ian P. G.; Behrens, Sebastian; Spormann, Alfred M.; Semprini, Lewis

    2010-04-01

    A continuous-flow column study was conducted to analyze the reductive dehalogenation of trichloroethene (TCE) with aquifer material with high content of iron oxides. The column was bioaugmented with the Point Mugu (PM) culture, which is a mixed microbial enrichment culture capable of completely transforming TCE to ethene (ETH). We determined whether lactate, formate, or propionate fermentation resulted in more effective dehalogenation. Reductive dehalogenation, fermentation, and sulfate, Fe(III), and Mn(IV) reduction were all exhibited within the column. Different steady-states of dehalogenation were achieved based on the concentration of substrates added, with effective transformation to ETH obtained when ample electron donor equivalents were provided. Most of the metabolic reducing equivalents were channeled to sulfate, Fe(III), and Mn(IV) reduction. When similar electron reducing equivalents were added, the most effective dehalogenation was achieved with formate, with 14% of the electron equivalents going towards dehalogenation reactions, compared to 6.5% for lactate and 9.6% for propionate. Effective dehalogenation was maintained over 1000 days of column operation. Over 90% of electron equivalents added could be accounted for by the different electron accepting processes in the column, with 50% associated with soluble and precipitated Fe(II) and Mn(II). Bulk Fe(III) and Mn(IV) reduction was rather associated with lactate and propionate addition than formate addition. Sulfate reduction was a competing electron acceptor reaction with all three electron donors. DNA was extracted from solid coupon samples obtained during the course of the experiment and analyzed using 16S rRNA gene clone libraries and quantitative PCR. Lactate and propionate addition resulted in a significant increase in Geobacter, Spirochaetes, and Desulfitobacterium phylotypes relative to " Dehalococcoides" when compared to formate addition. Results from the molecular biological analyses support

  1. Recolonization of macrofauna in unpolluted sands placed in a polluted yachting harbour: A field approach using experimental trays

    Science.gov (United States)

    Guerra-García, J. M.; García-Gómez, J. C.

    2009-01-01

    A field experiment using trays was conducted at Ceuta's yachting harbour, North Africa, to study the effect in recolonization of placing trays with unpolluted defaunate sediments (fine and gross sands with low contents of organic matter) inside an enclosed yachting harbour characterized by high percentages of silt and clay and high concentrations of organic matter. Sediment recolonization in the trays was mainly undertaken by the species living naturally at the yachting harbour, which recolonized both uncontaminated gross and fine sand trays (such as the crustaceans Corophium runcicorne, Corophium sextonae and Nebalia bipes, the mollusc Parvicardium exiguum and the polychaete Pseudomalacoceros tridentata). However, other species like the polychaetes Cirriformia tentaculata and Platynereis dumerilii, although also abundant in the yachting harbour, were unable to colonize the trays through transport of larvae and/or adults in the water column. The recolonization was very quick, and after the first month, the values of abundance, species richness, diversity and evenness were similar in the experimental trays and in the reference area (yachting harbour). Although the multivariate analysis showed that the species composition differed between the trays and the reference area, there were no significant differences in recolonization of gross and fine sands, indicating that other factors different from the granulometry are modulating the recolonization patterns.

  2. Characteristic sediment and water column chlorophyll-a in the sea cucumber’s Paracaudina sp. habitat on the Kenjeran Water, Surabaya

    Science.gov (United States)

    Widianingsih, W.; Zaenuri, M.; Anggoro, S.; Kusumaningrum, H. P.; Hartati, R.

    2018-03-01

    The study of characteristic sediment and water column chlorophyll-a has an important role in the sea cucumber habitat. Sediment chlorophyll-a represents a productivity primer for the benthic community. This research has a purpose to investigate characteristic sediment and water column chlorophyll-a on the Kenjeran water, Surabaya. Sediment samples were collected by the ekman grab for analysis, grain size and nutrient. The sample for sediment chlorophyll-a was taken by core sampler. The water samples were taken with Nansen Bottles. According to the research result, the values of sediment chlorophyll-a at station 10, 11 and 12 were higher than the other stations. In contrast, the value of chlorophyll-a in the column water had almost the same value for each station. The sediment chlorophyll-a value on clay and silt sediment type was higher than the fine sand and coarse sediment type. The suitable habitat characteristic for Paracaudina sp. was clay and silt sediment with sediment chlorophyll concentration ranging from 347.82 mg·m-2 to 1135.52 mg·m-2.

  3. Photoluminescence emission at room temperature in zinc oxide nano-columns

    International Nuclear Information System (INIS)

    Rocha, L.S.R.; Deus, R.C.; Foschini, C.R.; Moura, F.; Garcia, F. Gonzalez; Simões, A.Z.

    2014-01-01

    Highlights: • ZnO nanoparticles were obtained by microwave-hydrothermal method. • X-ray diffraction reveals a hexagonal structure. • Photoluminescence emission evidenced two absorption peaks, at around 480 nm and 590 nm wavelengths. - Abstract: Hydrothermal microwave method (HTMW) was used to synthesize crystalline zinc oxide (ZnO) nano-columns at the temperature of 120 °C with a soaking time of 8 min. ZnO nano-columns were characterized by using X-ray analyses (XRD), infrared spectroscopy (FT-IR), thermogravimetric analyses (TG-DTA), field emission gun and transmission electron microscopy (FEG-SEM and TEM) and photoluminescence properties (PL). XRD results indicated that the ZnO nano-columns are free of any impurity phase and crystallize in the hexagonal structure. Typical FT-IR spectra for ZnO nano-columns presented well defined bands, indicating a substantial short-range order in the system. PL spectra consist of a broad band at 590 nm and narrow band at 480 nm corresponding to a near-band edge emission related to the recombination of excitons and level emission related to structural defects. These results show that the HTMW synthesis route is rapid, cost effective, and could be used as an alternative to obtain ZnO nano-columns in the temperature of 120 °C for 8 min

  4. Photoluminescence emission at room temperature in zinc oxide nano-columns

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, L.S.R.; Deus, R.C. [Universidade Estadual Paulista – Unesp, Faculdade de Engenharia de Guaratinguetá, Av. Dr. Ariberto Pereira da Cunha, 333, Bairro Portal das Colinas, CEP 12516-410 Guaratinguetá, SP (Brazil); Foschini, C.R. [Universidade Estadual Paulista – Unesp, Instituto de Química, Laboratório Interdisciplinar em Cerâmica (LIEC), Rua Professor Francisco Degni s/n, CEP 14800-90 Araraquara, SP (Brazil); Moura, F.; Garcia, F. Gonzalez [Universidade Federal de Itajubá – Unifei, Campus Itabira, Rua São Paulo, 377, Bairro Amazonas, CEP 35900-37 Itabira, MG (Brazil); Simões, A.Z., E-mail: alezipo@yahoo.com [Universidade Estadual Paulista – Unesp, Faculdade de Engenharia de Guaratinguetá, Av. Dr. Ariberto Pereira da Cunha, 333, Bairro Portal das Colinas, CEP 12516-410 Guaratinguetá, SP (Brazil)

    2014-02-01

    Highlights: • ZnO nanoparticles were obtained by microwave-hydrothermal method. • X-ray diffraction reveals a hexagonal structure. • Photoluminescence emission evidenced two absorption peaks, at around 480 nm and 590 nm wavelengths. - Abstract: Hydrothermal microwave method (HTMW) was used to synthesize crystalline zinc oxide (ZnO) nano-columns at the temperature of 120 °C with a soaking time of 8 min. ZnO nano-columns were characterized by using X-ray analyses (XRD), infrared spectroscopy (FT-IR), thermogravimetric analyses (TG-DTA), field emission gun and transmission electron microscopy (FEG-SEM and TEM) and photoluminescence properties (PL). XRD results indicated that the ZnO nano-columns are free of any impurity phase and crystallize in the hexagonal structure. Typical FT-IR spectra for ZnO nano-columns presented well defined bands, indicating a substantial short-range order in the system. PL spectra consist of a broad band at 590 nm and narrow band at 480 nm corresponding to a near-band edge emission related to the recombination of excitons and level emission related to structural defects. These results show that the HTMW synthesis route is rapid, cost effective, and could be used as an alternative to obtain ZnO nano-columns in the temperature of 120 °C for 8 min.

  5. Excitation of THz hybrid modes in an elliptical dielectric rod waveguide with a cold collisionless unmagnetized plasma column by an annular electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Rahmani, Z., E-mail: z.rahmani@kashanu.ac.ir; Safari, S. [Department of Laser and Photonics, Faculty of Physics, University of Kashan, Kashan, Islamic Republic of Iran (Iran, Islamic Republic of); Heidari-Semiromi, E. [Department of Condense Matter, Faculty of Physics, University of Kashan, Kashan, Islamic Republic of Iran (Iran, Islamic Republic of)

    2016-06-15

    The dispersion relation of electromagnetic waves propagating in an elliptical plasma waveguide with a cold collisionless unmagnetized plasma column and a dielectric rod is studied analytically. The frequency spectrum of the hybrid waves and the growth rate for excitation of the waves by a thin annular relativistic elliptical electron beam (TAREEB) is obtained. The effects of relative permittivity constant of dielectric rod, geometrical dimensions, plasma frequency, accelerating voltage, and current density of TAREEB on the growth rate and frequency spectra of the waveguide will be investigated.

  6. Aggregation and transport of rutile titanium dioxide nanoparticles with montmorillonite and diatomite in the presence of phosphate in porous sand.

    Science.gov (United States)

    Guo, Peng; Xu, Nan; Li, Duo; Huangfu, Xinxing; Li, Zuling

    2018-08-01

    Crop soil is inevitably contaminated by the excess of phosphate (P) fertilizers. A large amount of nanoparticle titanium dioxide (nTiO 2 ) entered soils as well due to the wide use of engineered nanomaterials. It is of great urgency and a high priority to investigate the mechanisms of nTiO 2 deposition with the presence of P in crop soils. This study investigated the transport behavior of (1.0 g L -1 ) rutile nTiO 2 with two representative clay particles (montmorillonite or diatomite) in the presence of P through the saturated quartz sand. In 10 mM NaCl electrolyte solution at pH 6.0, the recovery percentage of nTiO 2 was 36.3% from sand column. Nevertheless, it was reduced to 18.6% and 11.1% while montmorillonite and diatomite present in suspensions, respectively. Obviously, the improvement of nTiO 2 retention in sand was more pronounced by diatomite than montmorillonite. The likely mechanism for this result was that large aggregates were formed due to the attachment of nTiO 2 to montmorillonite and diatomite. Moreover, the surface of diatomite with the larger hydrodynamic radius was less negatively charged by comparison with montmorillonite. However, this phenomenon disappeared with the addition of P. P adsorption increases the repulsive force between particles and sand and the fast release of attached nTiO 2 -montmorillonite and diatomite from sand. The two-site kinetic retention model and the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory suggested that the combination of k 1/ k 1d , k 2 and secondary minimum energy can be used to accurately describe the attachment of nTiO 2 -montmorillonite and diatomite to sand in the presence of P. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Strength and microstructure characteristics of the recycled rubber tire-sand mixtures as lightweight backfill.

    Science.gov (United States)

    Zhang, Tao; Cai, Guojun; Duan, Weihong

    2018-02-01

    The disposal of scrap rubber tires has induced critical environmental issue worldwide due to the rapid increase in the number of vehicles. Recycled scrap tires as a construction material in civil engineering have significant environmental benefits from a waste management perspective. A systematic study that deals with strength and microstructure characteristics of the rubber-sand mixtures is initiated, and mechanical response of the mixtures is discussed in this investigation. Experiments were conducted to evaluate the effects of rubber fraction on the basic properties including mass density (ρ), stress-strain characteristics, shear strength, and unconfined compression strength (q u ) of the rubber-sand mixtures. Additionally, scanning electron microscopy (SEM) was carried out to reveal the microstructure characteristics of the mixtures with various rubber fractions. A discussion on the micromechanics of the mixtures also was conducted. This study demonstrates that the ρ, friction angle, and q u decrease linearly with an increase in rubber fraction, whereas shear strain at peak increases. The stress-strain characteristics of the rubber-sand mixtures shift from brittle to ductile as the rubber fraction increase. These changes are attributed to remarkably lower stiffness and higher compressibility of the rubber particle compared with those of the conventional mineral aggregates. With an increase in the rubber fraction, the mechanical response of rubber-sand mixtures exhibits two types: sand-like material and rubber-like material. Rubber particle possesses the capacity to prevent the contacted sand particles from sliding at lower rubber fraction, whereas it transmits the applied loadings as the rubber fraction increased. This outcome reinforces the practicability of using recycled rubber tire-sand mixtures as a lightweight backfill in subbase/base applications.

  8. Column-Oriented Database Systems (Tutorial)

    NARCIS (Netherlands)

    D. Abadi; P.A. Boncz (Peter); S. Harizopoulos

    2009-01-01

    textabstractColumn-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as

  9. bentonite-sand mixture as new backfill/buffer material

    International Nuclear Information System (INIS)

    Cui Suli; Liu Jisheng; Zhang Huyuan; Liang Jian

    2008-01-01

    The mixture of bentonite and quartz sand is suggested as a new backfill/buffer material for geological disposal of HLW. To improve the further design of underground laboratory and in-situ industrial construction test, the optimization of sand addition to bentonite is focused at present research stage. Based on summarizing the research results abroad, laboratory tests were conducted on the mixture of GMZ001 bentonite and quartz sand, such as compaction test and swelling tests etc. Test data shows that GMZ bentonite-sand mixture exhibits a favorite compaction with a 30% sand addition, a highest swelling pressure with a 20% sand addition, and a decreasing plasticity with increases in sand addition and pore liquid concentration. (authors)

  10. Comparison between predicted and observed sand waves and sand banks in the North Sea

    NARCIS (Netherlands)

    Hulscher, Suzanne J.M.H.; van den Brink, G.M.

    2001-01-01

    For the first time a prediction model of regular morphological patterns on the seabed was tested against observations of sand wave and sand bank occurrence in the entire North Sea. The model, which originates from first physical principles, predicts this occurrence via two dimensionless parameters

  11. Critical State of Sand Matrix Soils

    Science.gov (United States)

    Marto, Aminaton; Tan, Choy Soon; Makhtar, Ahmad Mahir; Kung Leong, Tiong

    2014-01-01

    The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, λ, and Γ. The range of the value of M, λ, and Γ is 0.803–0.998, 0.144–0.248, and 1.727–2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated. PMID:24757417

  12. Analysis of the implementation of a sand bed type filter for the venting of a nuclear power plant

    International Nuclear Information System (INIS)

    Cuevas V, D.; Sainz M, E.; Ortiz V, J.

    2017-09-01

    The filtered venting of the containment has been adopted in European countries to mitigate the consequences derived from the excess pressure of the containment during a severe accident. When venting has taken place, the fission products are released directly into the environment, unless a filter is placed in the path of the same, so various types of filters are used to trap the fission products. The containment venting filters currently installed use different filtering technologies that involve more than one medium. Those who use water as the first stage of filtration are called wet systems, are equipped with additional stages to eliminate water drops and emissions of fine aerosols, and may even be equipped with an element that contains certain means of absorption for the gaseous iodine species filtration. Other designs, based on deep bed filtration as the main retention stage, called dry filters; use metal fiber, ceramic or sand filtration media to trap aerosols. The present work evaluates the hydraulic characteristics of the sand bed type filter designed by EDF as a candidate to be installed in the containment of the BWR Mark II (primary containment type of the Laguna Verde nuclear power plant). The evaluation of the sand bed filter was performed using the OpenFOAM open source software package. Models of each zone of the filtering device were generated and by means of a series of parametric calculations of computational fluid mechanics, the relevant hydrodynamic characteristics of the device were obtained, such as pressure drops against mass flow and pressure fields and velocity under different operating conditions. On the other hand, the validation of the sand bed filter model was made when comparing the results of experimental tests carried out in a sand column of the PITEAS program (1985-1986) against the simulation in OpenFOAM. The results obtained are very close to those obtained experimentally. (Author)

  13. Family of columns isospectral to gravity-loaded columns with tip force: A discrete approach

    Science.gov (United States)

    Ramachandran, Nirmal; Ganguli, Ranjan

    2018-06-01

    A discrete model is introduced to analyze transverse vibration of straight, clamped-free (CF) columns of variable cross-sectional geometry under the influence of gravity and a constant axial force at the tip. The discrete model is used to determine critical combinations of loading parameters - a gravity parameter and a tip force parameter - that cause onset of dynamic instability in the CF column. A methodology, based on matrix-factorization, is described to transform the discrete model into a family of models corresponding to weightless and unloaded clamped-free (WUCF) columns, each with a transverse vibration spectrum isospectral to the original model. Characteristics of models in this isospectral family are dependent on three transformation parameters. A procedure is discussed to convert the isospectral discrete model description into geometric description of realistic columns i.e. from the discrete model, we construct isospectral WUCF columns with rectangular cross-sections varying in width and depth. As part of numerical studies to demonstrate efficacy of techniques presented, frequency parameters of a uniform column and three types of tapered CF columns under different combinations of loading parameters are obtained from the discrete model. Critical combinations of these parameters for a typical tapered column are derived. These results match with published results. Example CF columns, under arbitrarily-chosen combinations of loading parameters are considered and for each combination, isospectral WUCF columns are constructed. Role of transformation parameters in determining characteristics of isospectral columns is discussed and optimum values are deduced. Natural frequencies of these WUCF columns computed using Finite Element Method (FEM) match well with those of the given gravity-loaded CF column with tip force, hence confirming isospectrality.

  14. Production and global transport of Titan's sand particles

    Science.gov (United States)

    Barnes, Jason W.; Lorenz, Ralph D.; Radebaugh, Jani; Hayes, Alexander G.; Arnold, Karl; Chandler, Clayton

    2015-06-01

    Previous authors have suggested that Titan's individual sand particles form by either sintering or by lithification and erosion. We suggest two new mechanisms for the production of Titan's organic sand particles that would occur within bodies of liquid: flocculation and evaporitic precipitation. Such production mechanisms would suggest discrete sand sources in dry lakebeds. We search for such sources, but find no convincing candidates with the present Cassini Visual and Infrared Mapping Spectrometer coverage. As a result we propose that Titan's equatorial dunes may represent a single, global sand sea with west-to-east transport providing sources and sinks for sand in each interconnected basin. The sand might then be transported around Xanadu by fast-moving Barchan dune chains and/or fluvial transport in transient riverbeds. A river at the Xanadu/Shangri-La border could explain the sharp edge of the sand sea there, much like the Kuiseb River stops the Namib Sand Sea in southwest Africa on Earth. Future missions could use the composition of Titan's sands to constrain the global hydrocarbon cycle.

  15. High temperature thermal energy storage in moving sand

    Science.gov (United States)

    Turner, R. H.; Awaya, H. I.

    1978-01-01

    Several high-temperature (to 500 C) heat-storage systems using sand as the storage medium are described. The advantages of sand as a storage medium include low cost for sand, widespread availability, non-toxicity, non-degradation characteristics, easy containment, and safety. The systems considered include: stationary sand with closely spaced tubes throughout the volume, the use of a fluidized bed, use of conveyor belt transporter, and the use of a blower rapid transport system. For a stationary sand bed, very close spacing of heat transfer tubes throughout the volume is required, manifesting as high power related system cost. The suggestion of moving sand past or around pipes is intended to reduce the power related costs at the penalty of added system complexity. Preliminary system cost estimates are offered. These rough calculations indicate that mobile sand heat storage systems cost less than the stationary sand approach.

  16. Distillation Column Flooding Predictor

    Energy Technology Data Exchange (ETDEWEB)

    George E. Dzyacky

    2010-11-23

    The Flooding Predictor™ is a patented advanced control technology proven in research at the Separations Research Program, University of Texas at Austin, to increase distillation column throughput by over 6%, while also increasing energy efficiency by 10%. The research was conducted under a U. S. Department of Energy Cooperative Agreement awarded to George Dzyacky of 2ndpoint, LLC. The Flooding Predictor™ works by detecting the incipient flood point and controlling the column closer to its actual hydraulic limit than historical practices have allowed. Further, the technology uses existing column instrumentation, meaning no additional refining infrastructure is required. Refiners often push distillation columns to maximize throughput, improve separation, or simply to achieve day-to-day optimization. Attempting to achieve such operating objectives is a tricky undertaking that can result in flooding. Operators and advanced control strategies alike rely on the conventional use of delta-pressure instrumentation to approximate the column’s approach to flood. But column delta-pressure is more an inference of the column’s approach to flood than it is an actual measurement of it. As a consequence, delta pressure limits are established conservatively in order to operate in a regime where the column is never expected to flood. As a result, there is much “left on the table” when operating in such a regime, i.e. the capacity difference between controlling the column to an upper delta-pressure limit and controlling it to the actual hydraulic limit. The Flooding Predictor™, an innovative pattern recognition technology, controls columns at their actual hydraulic limit, which research shows leads to a throughput increase of over 6%. Controlling closer to the hydraulic limit also permits operation in a sweet spot of increased energy-efficiency. In this region of increased column loading, the Flooding Predictor is able to exploit the benefits of higher liquid

  17. Annular pulse column development studies

    International Nuclear Information System (INIS)

    Benedict, G.E.

    1980-01-01

    The capacity of critically safe cylindrical pulse columns limits the size of nuclear fuel solvent extraction plants because of the limited cross-sectional area of plutonium, U-235, or U-233 processing columns. Thus, there is a need to increase the cross-sectional area of these columns. This can be accomplished through the use of a column having an annular cross section. The preliminary testing of a pilot-plant-scale annular column has been completed and is reported herein. The column is made from 152.4-mm (6-in.) glass pipe sections with an 89-mm (3.5-in.) o.d. internal tube, giving an annular width of 32-mm (1.25-in.). Louver plates are used to swirl the column contents to prevent channeling of the phases. The data from this testing indicate that this approach can successfully provide larger-cross-section critically safe pulse columns. While the capacity is only 70% of that of a cylindrical column of similar cross section, the efficiency is almost identical to that of a cylindrical column. No evidence was seen of any non-uniform pulsing action from one side of the column to the other

  18. Sand to Root Transfer of PAHs and PCBs by Carrots Grown on Sand with Pure Substances and Biosolids Amended Sand

    OpenAIRE

    Sablayrolles, Caroline; Montréjaud-Vignoles, Mireille; Silvestre, Jérôme; Patria, Lucie

    2006-01-01

    A study on behaviour of trace organic compounds (Polycyclic Aromatic Hydrocarbons, PAH, and Polychlorinated Biphenyls, PCB) in a sand-plant system has been carried out, with the reclamation of wastewater treatment plant biosolids for agriculture in mind. Carrot plants (Daucus carota) were grown on soilless culture (sand), to provide optimal transfer conditions, in plant containers inside a temperature regulated greenhouse. There were two types of experiment. The trace organic compounds have i...

  19. Depth sectioning using electron energy loss spectroscopy

    International Nuclear Information System (INIS)

    D'Alfonso, A J; Findlay, S D; Allen, L J; Cosgriff, E C; Kirkland, A I; Nellist, P D; Oxley, M P

    2008-01-01

    The continued development of electron probe aberration correctors for scanning transmission electron microscopy has enabled finer electron probes, allowing atomic resolution column-by-column electron energy loss spectroscopy. Finer electron probes have also led to a decrease in the probe depth of focus, facilitating optical slicing or depth sectioning of samples. The inclusion of post specimen aberration corrected image forming lenses allows for scanning confocal electron microscopy with further improved depth resolution and selectivity. We show that in both scanning transmission electron microscopy and scanning confocal electron microscopy geometries, by performing a three dimensional raster scan through a specimen and detecting electrons scattered with a characteristic energy loss, it will be possible to determine the location of isolated impurities embedded within the bulk.

  20. FeS-coated sand for removal of arsenic(III) under anaerobic conditions in permeable reactive barriers

    Science.gov (United States)

    Han, Y.-S.; Gallegos, T.J.; Demond, A.H.; Hayes, K.F.

    2011-01-01

    Iron sulfide (as mackinawite, FeS) has shown considerable promise as a material for the removal of As(III) under anoxic conditions. However, as a nanoparticulate material, synthetic FeS is not suitable for use in conventional permeable reactive barriers (PRBs). This study developed a methodology for coating a natural silica sand to produce a material of an appropriate diameter for a PRB. Aging time, pH, rinse time, and volume ratios were varied, with a maximum coating of 4.0 mg FeS/g sand achieved using a pH 5.5 solution at a 1:4 volume ratio (sand: 2 g/L FeS suspension), three days of aging and no rinsing. Comparing the mass deposited on the sand, which had a natural iron-oxide coating, with and without chemical washing showed that the iron-oxide coating was essential to the formation of a stable FeS coating. Scanning electron microscopy images of the FeS-coated sand showed a patchwise FeS surface coating. X-ray photoelectron spectroscopy showed a partial oxidation of the Fe(II) to Fe(III) during the coating process, and some oxidation of S to polysulfides. Removal of As(III) by FeS-coated sand was 30% of that by nanoparticulate FeS at pH 5 and 7. At pH 9, the relative removal was 400%, perhaps due to the natural oxide coating of the sand or a secondary mineral phase from mackinawite oxidation. Although many studies have investigated the coating of sands with iron oxides, little prior work reports coating with iron sulfides. The results suggest that a suitable PRB material for the removal of As(III) under anoxic conditions can be produced through the deposition of a coating of FeS onto natural silica sand with an iron-oxide coating. ?? 2010 Elsevier Ltd.

  1. Performance of Elaeis Guineensis Leaves Compost in Filter Media for Stormwater Treament Through Column Study

    Science.gov (United States)

    Takaijudin, H.; Ghani, A. A.; Zakaria, N. A.; Tze, L. L.

    2016-07-01

    Compost based materials arv e widely used in filter media for improving soil capability and plant growth. The aim of this paper is to evaluate different types of compost materials used in engineered soil media through soil column investigation. Three (3) column, namely C1 (control), C2 and C3 had different types compost (10%) which were, commercial compost namely PEATGRO, Compost A and Compost B were prepared with 60% medium sand and 30% of topsoil. The diluted stormwater runoff was flushed to the columns and it was run for six (6) hour experiment. The influent and effluent samples were collected and tested for Water Quality Index (WQI) parameters. The results deduced that C3 with Elaeis Guineensis leaves compost (Compost B) achieved 90.45 (Class II) better than control condition which accomplished 84 (Class II) based on WQI Classification. C3 with Compost A (African Mahogany Leaves Compost) obtained only 59.39 (Class III). C3 with the composition of Compost B effectively removed most pollutants, including Chemical Oxygen Demand (COD, Ammoniacal Nitrogen (NH3-N), were reduced by 89±4% and 96.6±0.9%, respectively. The result concluded that Elaeis Guineensis leaves compost is recommended to be used as part of engineered soil media due to its capabilities in eliminating stormwater pollutants.

  2. Column-Oriented Database Systems (Tutorial)

    OpenAIRE

    Abadi, D.; Boncz, Peter; Harizopoulos, S.

    2009-01-01

    textabstractColumn-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as opposed to traditional database systems that store entire records (rows) one after the other. Reading a subset of a table’s columns becomes faster, at the potential expense of excessive disk-head s...

  3. Synthesis and characterization of silica gel from siliceous sands of southern Tunisia

    Directory of Open Access Journals (Sweden)

    Ali Sdiri

    2014-09-01

    Full Text Available The present work aimed to achieve valorization of Albian sands for the preparation of sodium silicates that are commonly used as a precursor to prepare silica gel. A siliceous sand sample was mixed with sodium carbonate and heated at a high temperature (1060 °C to prepare sodium silicates. The sodium silicates were dissolved in distilled water to obtain high quality sodium silicate solution. Hydrochloric acid was then slowly added to the hydrated sodium silicates to obtain silica gel. The collected raw siliceous sands, as well as the prepared silica gels, were characterized by different techniques, such as X-ray fluorescence (XRF, X-ray diffraction (XRD, scanning electron microscopy (SEM and thermal analysis (DSC. XRF confirmed that the detrital sand deposits of southern Tunisia contain high amounts of silica, with content ranging from 88.8% to 97.5%. The internal porosity varied between 17% and 22%, and the specific surface area was less than 5 m2/g. After the treatment described above, it was observed that the porosity of the obtained silica gel reached 57% and the specific surface area exceeded 340 m2/g. Nitrogen adsorption isotherms showed that the prepared silica gels are microporous and mesoporous materials with high adsorption capacities. These results suggest that the obtained silica gels are promising materials for numerous environmental applications.

  4. Optimising electron microscopy experiment through electron optics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Y. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France); Hitachi High-Technologies Corporation, 882, Ichige, Hitachinaka, Ibaraki 312-8504 (Japan); Gatel, C.; Snoeck, E. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France); Houdellier, F., E-mail: florent.houdellier@cemes.fr [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France)

    2017-04-15

    We developed a new type of electron trajectories simulation inside a complete model of a modern transmission electron microscope (TEM). Our model incorporates the precise and real design of each element constituting a TEM, i.e. the field emission (FE) cathode, the extraction optic and acceleration stages of a 300 kV cold field emission gun, the illumination lenses, the objective lens, the intermediate and projection lenses. Full trajectories can be computed using magnetically saturated or non-saturated round lenses, magnetic deflectors and even non-cylindrical symmetry elements like electrostatic biprism. This multi-scale model gathers nanometer size components (FE tip) with parts of meter length (illumination and projection systems). We demonstrate that non-trivial TEM experiments requiring specific and complex optical configurations can be simulated and optimized prior to any experiment using such model. We show that all the currents set in all optical elements of the simulated column can be implemented in the real column (I2TEM in CEMES) and used as starting alignment for the requested experiment. We argue that the combination of such complete electron trajectory simulations in the whole TEM column with automatic optimization of the microscope parameters for optimal experimental data (images, diffraction, spectra) allows drastically simplifying the implementation of complex experiments in TEM and will facilitate the development of advanced use of the electron microscope in the near future. - Highlights: • Using dedicated electron optics software, we calculate full electrons trajectories inside a modern transmission electron microscope. • We have determined how to deal with multi-scale electron optics elements like high voltage cold field emission source. • W • e have succeed to model both weak and strong magnetic lenses whether in saturated or unsaturated conditions as well as electrostatic biprism and magnetic deflectors. • We have applied this model

  5. Optimising electron microscopy experiment through electron optics simulation

    International Nuclear Information System (INIS)

    Kubo, Y.; Gatel, C.; Snoeck, E.; Houdellier, F.

    2017-01-01

    We developed a new type of electron trajectories simulation inside a complete model of a modern transmission electron microscope (TEM). Our model incorporates the precise and real design of each element constituting a TEM, i.e. the field emission (FE) cathode, the extraction optic and acceleration stages of a 300 kV cold field emission gun, the illumination lenses, the objective lens, the intermediate and projection lenses. Full trajectories can be computed using magnetically saturated or non-saturated round lenses, magnetic deflectors and even non-cylindrical symmetry elements like electrostatic biprism. This multi-scale model gathers nanometer size components (FE tip) with parts of meter length (illumination and projection systems). We demonstrate that non-trivial TEM experiments requiring specific and complex optical configurations can be simulated and optimized prior to any experiment using such model. We show that all the currents set in all optical elements of the simulated column can be implemented in the real column (I2TEM in CEMES) and used as starting alignment for the requested experiment. We argue that the combination of such complete electron trajectory simulations in the whole TEM column with automatic optimization of the microscope parameters for optimal experimental data (images, diffraction, spectra) allows drastically simplifying the implementation of complex experiments in TEM and will facilitate the development of advanced use of the electron microscope in the near future. - Highlights: • Using dedicated electron optics software, we calculate full electrons trajectories inside a modern transmission electron microscope. • We have determined how to deal with multi-scale electron optics elements like high voltage cold field emission source. • W • e have succeed to model both weak and strong magnetic lenses whether in saturated or unsaturated conditions as well as electrostatic biprism and magnetic deflectors. • We have applied this model

  6. Nuclear reactor control column

    International Nuclear Information System (INIS)

    Bachovchin, D.M.

    1982-01-01

    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest crosssectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor

  7. Analysis of wind-blown sand movement over transverse dunes.

    Science.gov (United States)

    Jiang, Hong; Huang, Ning; Zhu, Yuanjian

    2014-12-01

    Wind-blown sand movement often occurs in a very complicated desert environment where sand dunes and ripples are the basic forms. However, most current studies on the theoretic and numerical models of wind-blown sand movement only consider ideal conditions such as steady wind velocity, flat sand surface, etc. In fact, the windward slope gradient plays a great role in the lift-off and sand particle saltation. In this paper, we propose a numerical model for the coupling effect between wind flow and saltating sand particles to simulate wind-blown sand movement over the slope surface and use the SIMPLE algorithm to calculate wind flow and simulate sands transport by tracking sand particle trajectories. We furthermore compare the result of numerical simulation with wind tunnel experiments. These results prove that sand particles have obvious effect on wind flow, especially that over the leeward slope. This study is a preliminary study on windblown sand movement in a complex terrain, and is of significance in the control of dust storms and land desertification.

  8. Column Selection for Biomedical Analysis Supported by Column Classification Based on Four Test Parameters.

    Science.gov (United States)

    Plenis, Alina; Rekowska, Natalia; Bączek, Tomasz

    2016-01-21

    This article focuses on correlating the column classification obtained from the method created at the Katholieke Universiteit Leuven (KUL), with the chromatographic resolution attained in biomedical separation. In the KUL system, each column is described with four parameters, which enables estimation of the FKUL value characterising similarity of those parameters to the selected reference stationary phase. Thus, a ranking list based on the FKUL value can be calculated for the chosen reference column, then correlated with the results of the column performance test. In this study, the column performance test was based on analysis of moclobemide and its two metabolites in human plasma by liquid chromatography (LC), using 18 columns. The comparative study was performed using traditional correlation of the FKUL values with the retention parameters of the analytes describing the column performance test. In order to deepen the comparative assessment of both data sets, factor analysis (FA) was also used. The obtained results indicated that the stationary phase classes, closely related according to the KUL method, yielded comparable separation for the target substances. Therefore, the column ranking system based on the FKUL-values could be considered supportive in the choice of the appropriate column for biomedical analysis.

  9. Sand consolidation

    Energy Technology Data Exchange (ETDEWEB)

    Spain, H H

    1965-01-21

    In a sand consolidation method in which there is injected a mixture of resin-forming liquids comprising an aryl-hydroxy low molecular weight compound, a water- soluble aldehyde, and a catalyst, an improvement is claimed which comprises diluting the resin-forming liquids with a diluent and with water so that the yield of the resin is sufficient to consolidate the sand particles with the minimum desirable pressure. The diluent may be mutually soluble in water and in the resin-forming liquids, and does not affect the setting time of the polymer. The aldehyde and the aryl-hydroxy compound may be in ratio of 5:1, and the diluent, methyl alcohol, is present in a ratio of 2:1 with reference to the water.

  10. Improvements in solvent extraction columns

    International Nuclear Information System (INIS)

    Aughwane, K.R.

    1987-01-01

    Solvent extraction columns are used in the reprocessing of irradiated nuclear fuel. For an effective reprocessing operation a solvent extraction column is required which is capable of distributing the feed over most of the column. The patent describes improvements in solvent extractions columns which allows the feed to be distributed over an increased length of column than was previously possible. (U.K.)

  11. Treatment of groundwater containing Mn(II), Fe(II), As(III) and Sb(III) by bioaugmented quartz-sand filters.

    Science.gov (United States)

    Bai, Yaohui; Chang, Yangyang; Liang, Jinsong; Chen, Chen; Qu, Jiuhui

    2016-12-01

    High concentrations of iron (Fe(II)) and manganese (Mn(II)) often occur simultaneously in groundwater. Previously, we demonstrated that Fe(II) and Mn(II) could be oxidized to biogenic Fe-Mn oxides (BFMO) via aeration and microbial oxidation, and the formed BFMO could further oxidize and adsorb other pollutants (e.g., arsenic (As(III)) and antimony (Sb(III))). To apply this finding to groundwater remediation, we established four quartz-sand columns for treating groundwater containing Fe(II), Mn(II), As(III), and Sb(III). A Mn-oxidizing bacterium (Pseudomonas sp. QJX-1) was inoculated into two parallel bioaugmented columns. Long-term treatment (120 d) showed that bioaugmentation accelerated the formation of Fe-Mn oxides, resulting in an increase in As and Sb removal. The bioaugmented columns also exhibited higher overall treatment effect and anti-shock load capacity than that of the non-bioaugmented columns. To clarify the causal relationship between the microbial community and treatment effect, we compared the biomass of active bacteria (reverse-transcribed real-time PCR), bacterial community composition (Miseq 16S rRNA sequencing) and community function (metagenomic sequencing) between the bioaugmented and non-bioaugmented columns. Results indicated that the QJX1 strain grew steadily and attached onto the filter material surface in the bioaugmented columns. In general, the inoculated strain did not significantly alter the composition of the indigenous bacterial community, but did improve the relative abundances of xenobiotic metabolism genes and Mn oxidation gene. Thus, bioaugmentation intensified microbial degradation/utilization for the direct removal of pollutants and increased the formation of Fe-Mn oxides for the indirect removal of pollutants. Our study provides an alternative method for the treatment of groundwater containing high Fe(II), Mn(II) and As/Sb. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Sands at Gusev Crater, Mars

    Science.gov (United States)

    Cabrol, Nathalie A.; Herkenhoff, Kenneth E.; Knoll, Andrew H.; Farmer, Jack D.; Arvidson, Raymond E.; Grin, E.A.; Li, Ron; Fenton, Lori; Cohen, B.; Bell, J.F.; Yingst, R. Aileen

    2014-01-01

    Processes, environments, and the energy associated with the transport and deposition of sand at Gusev Crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions. Bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the Spirit rover as it crossed the plains and went into the Columbia Hills. Fine-to-medium sand is ubiquitous in ripples and wind drifts. Most distributions show excess fine material, consistent with a predominance of wind erosion over the last 3.8 billion years. Negative skewness at West Valley is explained by the removal of fine sand during active erosion, or alternatively, by excess accumulation of coarse sand from a local source. The coarse to very coarse sand particles of ripple armors in the basaltic plains have a unique combination of size and shape. Their distribution display significant changes in their statistical moments within the ~400 m that separate the Columbia Memorial Station from Bonneville Crater. Results are consistent with aeolian and/or impact deposition, while the elongated and rounded shape of the grains forming the ripples, as well as their direction of origin, could point to Ma'adim Vallis as a possible source. For smaller particles on the traverse, our findings confirm that aeolian processes have dominated over impact and other processes to produce sands with the observed size and shape patterns across a spectrum of geologic (e.g., ripples and plains soils) and aerographic settings (e.g., wind shadows).

  13. Direct Chlorination of Zircon Sand

    International Nuclear Information System (INIS)

    Dwiretnani Sudjoko; Budi Sulistyo; Pristi Hartati; Sunardjo

    2002-01-01

    It was investigated the direct chlorination of zircon sand in a unit chlorination equipment. The process was in semi batch. The product gas was scrubbed in aqueous NaOH. It was search the influence of time, ratio of reactant and size of particle sand to the concentration of Zr and Si in the product. From these research it was found that as the times, ratio of reactant increased, the concentration of Zr increased, but the concentration of Si decreased, while as grain size of zircon sand decreased the concentration of Zr decreased, but the concentration of Si increased. (author)

  14. ( Anogeissus leiocarpus ) timber columns

    African Journals Online (AJOL)

    A procedure for designing axially loaded Ayin (Anogeissus leiocarpus) wood column or strut has been investigated. Instead of the usual categorization of columns into short, intermediate and slender according to the value of slenderness ratio, a continuous column formula representing the three categories was derived.

  15. Thermal Conductivity of Polymer Composite poypropilene-Sand

    International Nuclear Information System (INIS)

    Betha; Mashuri; Sudirman; Karo Karo, Aloma

    2001-01-01

    Thermal conductivity composite materials polypropylene (PP)-sand have been investigated. PP composite with sand to increase thermal conductivity from the polymer. The composite in this observation is done by mixing matrix (PP melt flow 2/10)and filler sand)by means tool labo plastomil. The result of thermal conductivity is composite of PP-sand which is obtained increase and followed by the raising of filler particle volume fraction. The analysis of thermal conductivity based on the model Cheng and Vachon, model Lewis and Nielsen where this model has the function to support experiment finding. It is proved that Lewis' and Nielsen's model almost approach experiment result. And then thermal conductivity raising will be analyzed by the model of pararel-series conductive with the two (2)phases system. It is showed that sand in PP MF 2 composite have the big role to increase the thermal conductivity than sand in PP MF 10 composition, but it is not easy to shape conductive medium

  16. Final report on Thermally Modified Sand demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-23

    The use of salt and salt/sand mixtures on icy roadway surfaces has dramatically increased during the past 30 years. Despite extensive documentation on salt related damage to the roadway improvements, vehicles and the environment, road maintenance departments have continued to rely on this practice. Road maintenance departments in northern climate areas have long recognized the safety benefits for public mobility on icy roadways from the use of sand. As an abrasive material, the sand improves the surface traction that results in more drivable and less hazardous road conditions during the winter months. Stockpiles of pure sand stored during the winter months oftentimes freeze into large unworkable, monolithic piles. To maintain a free-flowing condition, it has been found to be necessary to add salt to the sand. The addition of salt in amounts ranging from 5 to 10 percent to that of sand, is usually sufficient to provide relatively free-flowing abrasive material that could be stored in stockpiles and applied to icy road surfaces with conventional sand spreading trucks. Another alternative for winter storage of pure sand to maintain a free-flowing condition is in humidity-controlled, heated buildings. As would be expected, this method has high capital and operating costs. and not cost effective for general highway maintenance use. The invention demonstrated herein is a method of thermally modifying pure sand that will remain in a free-flowing state throughout the winter season without the need for the salt additive. The thermally modified sand provides an abrasive material that when applied to icy roads does not cause environmental and corrosive damage as done by the application of sand with salt. By employing a very simple process of freezing screened sand particles by forced air convection under subfreezing conditions, the invention creates a product that has significant value in terms of economic and environmental benefits.

  17. Evaluate of head loss, sediment value and copper removal in sand media (rapid sand filter

    Directory of Open Access Journals (Sweden)

    Daneshi Navab

    2014-06-01

    Full Text Available Along with the technology development and increasing consumption of water resources, we are experiencing low qualities in the mentioned resources. Copper brings about serious environment al pollution, threatening human health and ecosystem. This metal found variously in water resources and industrial activities. Therefore, it needs to treat the water resources from these excessive amounts. Different methods have used for this reason but the most used method during recent years has been the absorption by economic absorbers such as sand. Rapid sand filters usually used in water and wastewater treatment plants for water clarification. In this research, a single layer gravity rapid sand filter has used to reduce different concentrations of copper. sediment value and head loss arising in filter media is simulated by using combination of Carman-Kozeny, Rose and Gregory models in different discharges of rapid sand filter. Results have shown that with increasing in discharge and decreasing in input copper concentration, arriving time to given head loss, is increasing. In addition, results demonstrated that with increasing in copper concentration in influent, removal efficiency is decreasing somewhat. Results of this research can applied in an appropriate design of rapid sand filter to copper removal, a prediction of rapid sand filter ability to copper removal and an estimation of arising head loss during filter work thus evaluating of time interval backwash. DOI: http://dx.doi.org/10.3126/ije.v3i2.10641 International Journal of the Environment Vol.3(2 2014: 276-286

  18. In situ recovery of oil from Utah tar sand: a summary of tar sand research at the Laramie Energy Technology Center

    Energy Technology Data Exchange (ETDEWEB)

    Marchant, L.C.; Westhoff, J.D.

    1985-10-01

    This report describes work done by the United States Department of Energy's Laramie Energy Technology Center from 1971 through 1982 to develop technology for future recovery of oil from US tar sands. Work was concentrated on major US tar sand deposits that are found in Utah. Major objectives of the program were as follows: determine the feasibility of in situ recovery methods applied to tar sand deposits; and establish a system for classifying tar sand deposits relative to those characteristics that would affect the design and operation of various in situ recovery processes. Contents of this report include: (1) characterization of Utah tar sand; (2) laboratory extraction studies relative to Utah tar sand in situ methods; (3) geological site evaluation; (4) environmental assessments and water availability; (5) reverse combustion field experiment, TS-1C; (6) a reverse combustion followed by forward combustion field experiment, TS-2C; (7) tar sand permeability enhancement studies; (8) two-well steam injection experiment; (9) in situ steam-flood experiment, TS-1S; (10) design of a tar sand field experiment for air-stream co-injection, TS-4; (11) wastewater treatment and oil analyses; (12) economic evaluation of an in situ tar sand recovery process; and (13) appendix I (extraction studies involving Utah tar sands, surface methods). 70 figs., 68 tabs.

  19. Study on sand particles creep model and open pit mine landslide mechanism caused by sand fatigue liquefaction

    Science.gov (United States)

    Du, Dong-Ning; Wang, Lai-Gui; Zhang, Xiang-Dong; Zhang, Shu-Kun

    2017-06-01

    The sand particles in the sand - rock composite slope of the open pit mine occurs creep deformation and fatigue liquefaction under the action of vehicle load vibration and hydraulic gradient, which causes landslide geological disasters and it destroys the surface environment. To reveal the mechanism, a mechanics model based on the model considering the soil structural change with a new “plastic hinge” element is developed, to improve its constitutive and creep curve equations. Data from sand creep experiments are used to identify the parameters in the model and to validate the model. The results show that the mechanical model can describe the rotation progress between the sand particles, disclose the negative acceleration creep deformation stage during the third phase, and require fewer parameters while maintaining accuracy. It provides a new creep model considering rotation to analyze sand creep mechanism, which provides a theoretical basis for revealing the open pit mine landslide mechanism induced by creep deformation and fatigue liquefaction of sandy soil.

  20. Retorting of bituminous sands

    Energy Technology Data Exchange (ETDEWEB)

    Chaney, P E; Ince, R W; Mason, C M

    1872-09-26

    This method of recovering oil from mined tar sands involves forming compacted tar sands pieces by special conditioning treatment that provides low internal permeability. The compacted pieces are then retorted in fixed bed form. The conditioning treatment can involve rolling of preformed pellets, compaction in a mold or pressure extrusion. Substantial collapsing of the bed during retorting is avoided. (9 claims) (Abstract only - original article not available from T.U.)

  1. LIQUID-LIQUID EXTRACTION COLUMNS

    Science.gov (United States)

    Thornton, J.D.

    1957-12-31

    This patent relates to liquid-liquid extraction columns having a means for pulsing the liquid in the column to give it an oscillatory up and down movement, and consists of a packed column, an inlet pipe for the dispersed liquid phase and an outlet pipe for the continuous liquid phase located in the direct communication with the liquid in the lower part of said column, an inlet pipe for the continuous liquid phase and an outlet pipe for the dispersed liquid phase located in direct communication with the liquid in the upper part of said column, a tube having one end communicating with liquid in the lower part of said column and having its upper end located above the level of said outlet pipe for the dispersed phase, and a piston and cylinder connected to the upper end of said tube for applying a pulsating pneumatic pressure to the surface of the liquid in said tube so that said surface rises and falls in said tube.

  2. Use of emulsified vegetable oil to support bioremediation of TCE DNAPL in soil columns.

    Science.gov (United States)

    Harkness, Mark; Fisher, Angela

    2013-08-01

    The interaction between emulsified vegetable oil (EVO) and trichloroethylene (TCE) dense non-aqueous phase liquid (DNAPL) was observed using two soil columns and subsequent reductive dechlorination of TCE was monitored over a three year period. Dyed TCE DNAPL (~75 g) was emplaced in one column (DNAPL column), while the second was DNAPL-free (plume column). EVO was added to both columns and partitioning of the EVO into the TCE DNAPL was measured and quantified. TCE (1.9 mM) was added to the influent of the plume column to simulate conditions down gradient of a DNAPL source area and the columns were operated independently for more than one year, after which they were connected in series. Initially limited dechlorination of TCE to cDCE was observed in the DNAPL column, while the plume column supported complete reductive dechlorination of TCE to ethene. Upon connection and reamendment of the plume column with EVO, near saturation levels of TCE from the effluent of the DNAPL column were rapidly dechlorinated to c-DCE and VC in the plume column; however, this high rate dechlorination produced hydrochloric acid which overwhelmed the buffering capacity of the system and caused the pH to drop below 6.0. Dechlorination efficiency in the columns subsequently deteriorated, as measured by the chloride production and Dehalococcoides counts, but was restored by adding sodium bicarbonate buffer to the influent groundwater. Robust dechlorination was eventually observed in the DNAPL column, such that the TCE DNAPL was largely removed by the end of the study. Partitioning of the EVO into the DNAPL provided significant operational benefits to the remediation system both in terms of electron donor placement and longevity. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Use of sand wave habitats by silver hake

    Science.gov (United States)

    Auster, P.J.; Lindholm, J.; Schaub, S.; Funnell, G.; Kaufman, L.S.; Valentine, P.C.

    2003-01-01

    Silver hake Merluccius bilinearis are common members of fish communities in sand wave habitats on Georges Bank and on Stellwagen Bank in the Gulf of Maine. Observations of fish size v. sand wave period showed that silver hake are not randomly distributed within sand wave landscapes. Regression analyses showed a significant positive relationship between sand wave period and fish length. Correlation coefficients, however, were low, suggesting other interactions with sand wave morphology, the range of current velocities, and available prey may also influence their distribution. Direct contact with sand wave habitats varied over diel periods, with more fish resting on the seafloor during daytime than at night. Social foraging, in the form of polarized groups of fish swimming in linear formations during crepuscular and daytime periods, was also observed. Sand wave habitats may provide shelter from current flows and mediate fish-prey interactions. ?? 2003 The Fisheries Society of the British Isles.

  4. Tidal dynamics in the sand motor lagoon

    NARCIS (Netherlands)

    De Vries, S.; Radermacher, M.; De Schipper, M.A.; Stive, M.J.F.

    2015-01-01

    The Sand Motor is a mega-nourishment characterized by a very large sand volume of around 20 million m3 placed along the Dutch coast. The Sand Motor is a pilot project to evaluate the performance of an alternative nourishment strategy with respect to different functions of the coastal system. Within

  5. Numerical simulation of flow and compression of green sand

    DEFF Research Database (Denmark)

    Hovad, Emil

    The focus of the industrial PhD project was concentrated on the production of the sand mold (green sand) which gives the cast component its final geometrical shape. In order to ensure a high quality of the cast component, it is important to control the manufacturing process of the mold itself so...... that it is homogeneous and stable. Therefore gaining a basic understanding of how the flow and deposition of green sand should be characterized and modelled was important, so that it could be used for simulation of the manufacturing process of the sand mold. The flowability of the green sand is important when the sand...... flows down through the hopper filling the chamber with sand during the sand shot. The flowability of green sand is mostly governed by the amount of water and bentonite which both decrease it. The flowability and the internal forces thus control how well you can fill a complex mold geom-etry in which...

  6. Sand wave fields beneath the Loop Current, Gulf of Mexico: Reworking of fan sands

    Science.gov (United States)

    Kenyon, Neil H.; Akhmetzhanov, A.M.; Twichell, D.C.

    2002-01-01

    Extensive fields of large barchan-like sand waves and longitudinal sand ribbons have been mapped by deep-towed SeaMARC IA sidescan sonar on part of the middle and lower Mississippi Fan that lies in about 3200 m of water. The area is beneath the strongly flowing Loop Current. The bedforms have not been adequately sampled but probably consist of winnowed siliciclastic-foraminiferal sands. The size (about 200 m from wingtip to wingtip) and shape of the large barchans is consistent with a previously observed peak current speed of 30 cm/s, measured 25 m above the seabed. The types of small-scale bedforms and the scoured surfaces of chemical crusts, seen on nearby bottom photographs, indicate that near-bed currents in excess of 30 cm/s may sometimes occur. At the time of the survey the sand transport direction was to the northwest, in the opposite direction to the Loop Current but consistent with there being a deep boundary current along the foot of the Florida Escarpment. Some reworking of the underlying sandy turbidites and debris flow deposits is apparent on the sidescan sonar records. Reworking by deep-sea currents, resulting in erosion and in deposits characterised by coarsening upwards structures and cross-bedding, is a process that has been proposed for sand found in cores in shallower parts of the Gulf of Mexico. This process is more widespread than hitherto supposed. 

  7. Oil sands and the environment

    Energy Technology Data Exchange (ETDEWEB)

    Seeley, R. [Shell Canada Ltd., Calgary, AB (Canada). Calgary Research Centre

    2004-07-01

    Oil sands are a significant resource for Alberta and Canada with continuing growth opportunity. There is a need to ensure sustainable development of the oil sands resources from a social, economic and environmental perspective. The industry has succeeded in terms of proven reserves, technology advancements, reduced operating costs, reliability and market accessibility. Some of the major challenges facing the industry include high capital cost, infrastructure, social services and keeping pace with growth. This presentation outlined the proactive measures that the oil sands industry has taken to manage environmental issues such as sulphur dioxide and nitrogen oxide emissions, greenhouse gases, water management and land reclamation. tabs., figs.

  8. Alberta oil sands royalty regime

    International Nuclear Information System (INIS)

    Asgarpour, S.

    2004-01-01

    The long term objective of the Oil Sands Business Unit of Alberta Energy is to pave the way for Alberta's bitumen production to reach 3 million barrels per day by 2020. This presentation described the national government's role in resource development. It was emphasized that since the Crown is the owner of the oil sands resource, it would benefit by providing strategic leadership and by generating a larger royalty base. The oil sands fiscal regime was described with reference to generic royalty, risk sharing, investment, and project economics. Business rule principles were also outlined along with criteria for project expansions. Both upstream and downstream challenges and opportunities were listed. 4 figs

  9. Experimental study of optimal self compacting concrete with spent foundry sand as partial replacement for M-sand using Taguchi approach

    Directory of Open Access Journals (Sweden)

    Nirmala D.B.

    2016-06-01

    Full Text Available This paper presents the application of Taguchi approach to obtain optimal mix proportion for Self Compacting Concrete (SCC containing spent foundry sand and M-sand. Spent foundry sand is used as a partial replacement for M-sand. The SCC mix has seven control factors namely, Coarse aggregate, M-sand with Spent Foundry sand, Cement, Fly ash, Water, Super plasticizer and Viscosity modifying agent. Modified Nan Su method is used to proportion the initial SCC mix. L18 (21×37 Orthogonal Arrays (OA with the seven control factors having 3 levels is used in Taguchi approach which resulted in 18 SCC mix proportions. All mixtures are extensively tested both in fresh and hardened states to verify whether they meet the practical and technical requirements of SCC. The quality characteristics considering “Nominal the better” situation is applied to the test results to arrive at the optimal SCC mix proportion. Test results indicate that the optimal mix satisfies the requirements of fresh and hardened properties of SCC. The study reveals the feasibility of using spent foundry sand as a partial replacement of M-sand in SCC and also that Taguchi method is a reliable tool to arrive at optimal mix proportion of SCC.

  10. Experimental study of optimal self compacting concrete with spent foundry sand as partial replacement for M-sand using Taguchi approach

    Science.gov (United States)

    Nirmala, D. B.; Raviraj, S.

    2016-06-01

    This paper presents the application of Taguchi approach to obtain optimal mix proportion for Self Compacting Concrete (SCC) containing spent foundry sand and M-sand. Spent foundry sand is used as a partial replacement for M-sand. The SCC mix has seven control factors namely, Coarse aggregate, M-sand with Spent Foundry sand, Cement, Fly ash, Water, Super plasticizer and Viscosity modifying agent. Modified Nan Su method is used to proportion the initial SCC mix. L18 (21×37) Orthogonal Arrays (OA) with the seven control factors having 3 levels is used in Taguchi approach which resulted in 18 SCC mix proportions. All mixtures are extensively tested both in fresh and hardened states to verify whether they meet the practical and technical requirements of SCC. The quality characteristics considering "Nominal the better" situation is applied to the test results to arrive at the optimal SCC mix proportion. Test results indicate that the optimal mix satisfies the requirements of fresh and hardened properties of SCC. The study reveals the feasibility of using spent foundry sand as a partial replacement of M-sand in SCC and also that Taguchi method is a reliable tool to arrive at optimal mix proportion of SCC.

  11. A novel ionic liquid monolithic column and its separation properties in capillary electrochromatography

    International Nuclear Information System (INIS)

    Wang Yu; Deng Qiliang; Fang Guozhen; Pan Mingfei; Yu Yang; Wang Shuo

    2012-01-01

    Highlights: ► ILs as functional monomer for capillary monolithic column. ► Separation of alkylbenzenes, thiourea analogues, and amino acids. ► The column generate a stable reversed EOF from pH 2.0 to 12.0. ► The column efficiency of 147,000 plates m −1 was obtained for thiourea. - Abstract: A novel ionic liquid (IL) monolithic capillary column was successfully prepared by thermal free radical copolymerization of IL (1-vinyl-3-octylimidazolium chloride, ViOcIm + Cl − ) together with lauryl methacrylate (LMA) as the binary functional monomers and ethylene dimethacrylate (EDMA) as the cross-linker in binary porogen. The proportion of monomers, porogens and cross-linker in the polymerization mixture was optimized in detail. The resulting IL-monolithic column could not only generate a stable reversed electroosmotic flow (EOF) in a wide pH range (2.0–12.0), but also effectively eliminate the wall adsorption of the basic analytes. The obtained IL-monolithic columns were examined by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR). These results indicated that the IL-monolithic capillary column possessed good pore properties, mechanical stability and permeability. The column performance was also evaluated by separating different kinds of compounds, such as alkylbenzenes, thiourea and its analogues, and amino acids. The lowest plate height of ∼6.8 μm was obtained, which corresponded to column efficiency (theoretical plates, N) of ∼147,000 plates m −1 for thiourea. ILs, as a new type of functional monomer, present a promising option in the fabrication of the organic polymer-based monolithic columns in CEC.

  12. Oil sands tailings management project

    Energy Technology Data Exchange (ETDEWEB)

    Godwalt, C. [Alberta WaterSMART, Calgary, AB (Canada); Kotecha, P. [Suncor Energy Inc, Calgary, AB (Canada); Aumann, C. [Alberta Innovates - Technology Futures, Alberta Governement, AB (Canada)

    2010-11-15

    The Oil sands leadership initiative (OSLI) works with the Government of Alberta on the development of the oil sands industry, considering environmental, economical and social aspects. Water management was identified as one of most important areas to focus on. Alberta WaterSMART was requested to support the development and the management of projects resulting from the work done or underway in this field. The development of a regional water management solution stood out as the most interesting solution to obtain significant results. In the Athabasca Region, oil sands producers work independently on their water sourcing and disposal with particular attention to fresh water conservation and economics. The Athabasca River represents a source for mines and distant saline aquifers are the target of steam assisted gravity drainage (SAGD) operators. As part of a four-phase project aiming to study the environmental and economic footprint (EEF) benefit of alternatives for Athabasca oil sands production water supply and disposal, the purpose of the tailings water management project was to identify tailings treatment technologies that are ready to be implemented, and to design and evaluate solutions in order to improve regional oil sands production water sourcing and disposal. Alternatives were evaluated based on their total EEF, applying a lifecycle assessment methodology with a particular attention on the quantification of important performance indicators. 25 refs., 8 tabs., 40 figs.

  13. Oil sands tailings management project

    International Nuclear Information System (INIS)

    Godwalt, C.; Kotecha, P.; Aumann, C.

    2010-11-01

    The Oil sands leadership initiative (OSLI) works with the Government of Alberta on the development of the oil sands industry, considering environmental, economical and social aspects. Water management was identified as one of most important areas to focus on. Alberta WaterSMART was requested to support the development and the management of projects resulting from the work done or underway in this field. The development of a regional water management solution stood out as the most interesting solution to obtain significant results. In the Athabasca Region, oil sands producers work independently on their water sourcing and disposal with particular attention to fresh water conservation and economics. The Athabasca River represents a source for mines and distant saline aquifers are the target of steam assisted gravity drainage (SAGD) operators. As part of a four-phase project aiming to study the environmental and economic footprint (EEF) benefit of alternatives for Athabasca oil sands production water supply and disposal, the purpose of the tailings water management project was to identify tailings treatment technologies that are ready to be implemented, and to design and evaluate solutions in order to improve regional oil sands production water sourcing and disposal. Alternatives were evaluated based on their total EEF, applying a lifecycle assessment methodology with a particular attention on the quantification of important performance indicators. 25 refs., 8 tabs., 40 figs.

  14. Scalability of pre-packed preparative chromatography columns with different diameters and lengths taking into account extra column effects.

    Science.gov (United States)

    Schweiger, Susanne; Jungbauer, Alois

    2018-02-16

    Small pre-packed columns are commonly used to estimate the optimum run parameters for pilot and production scale. The question arises if the experiments obtained with these columns are scalable, because there are substantial changes in extra column volume when going from a very small scale to a benchtop column. In this study we demonstrate the scalability of pre-packed disposable and non-disposable columns of volumes in the range of 0.2-20 ml packed with various media using superficial velocities in the range of 30-500 cm/h. We found that the relative contribution of extra column band broadening to total band broadening was not only high for columns with small diameters, but also for columns with a larger volume due to their wider diameter. The extra column band broadening can be more than 50% for columns with volumes larger than 10 ml. An increase in column diameter leads to high additional extra column band broadening in the filter, frits, and adapters of the columns. We found a linear relationship between intra column band broadening and column length, which increased stepwise with increases in column diameter. This effect was also corroborated by CFD simulation. The intra column band broadening was the same for columns packed with different media. An empirical engineering equation and the data gained from the extra column effects allowed us to predict the intra, extra, and total column band broadening just from column length, diameter, and flow rate. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  15. Polydopamine-coated open tubular column for the separation of proteins by capillary electrochromatography.

    Science.gov (United States)

    Xiao, Xing; Wang, Wentao; Chen, Jia; Jia, Li

    2015-08-01

    The separation and determination of proteins in food is an important aspect in food industry. Inspired by the self-polymerization of dopamine under alkaline conditions and the natural adhesive properties of polydopamine, in this paper, a simple and economical method was developed for the preparation of polydopamine-coated open tubular column, in which ammonium persulfate was used as the source of oxygen to induce and facilitate the polymerization of dopamine to form polydopamine. In comparison with a naked fused-silica capillary, the direction and magnitude of the electro-osmotic flow of the as-prepared polydopamine-coated open tubular column could be manipulated by varying the pH values of background solutions due to the existence of amine and phenolic hydroxyl groups on polydopamine coating. The surface morphology of the polydopamine-coated open tubular column was studied by scanning electron microscopy, and the thickness of polydopamine coating was 106 nm. The performance of the polydopamine-coated open tubular column was validated by analysis of proteins. The relative standard deviations of migration times of proteins representing run-to-run, day-to-day, and column-to-column were less than 3.5%. In addition, the feasibility of the polydopamine-coated open tubular column for real samples was verified by the separation of proteins in chicken egg white and pure milk. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. A novel ionic liquid monolithic column and its separation properties in capillary electrochromatography.

    Science.gov (United States)

    Wang, Yu; Deng, Qi-Liang; Fang, Guo-Zhen; Pan, Ming-Fei; Yu, Yang; Wang, Shuo

    2012-01-27

    A novel ionic liquid (IL) monolithic capillary column was successfully prepared by thermal free radical copolymerization of IL (1-vinyl-3-octylimidazolium chloride, ViOcIm(+)Cl(-)) together with lauryl methacrylate (LMA) as the binary functional monomers and ethylene dimethacrylate (EDMA) as the cross-linker in binary porogen. The proportion of monomers, porogens and cross-linker in the polymerization mixture was optimized in detail. The resulting IL-monolithic column could not only generate a stable reversed electroosmotic flow (EOF) in a wide pH range (2.0-12.0), but also effectively eliminate the wall adsorption of the basic analytes. The obtained IL-monolithic columns were examined by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR). These results indicated that the IL-monolithic capillary column possessed good pore properties, mechanical stability and permeability. The column performance was also evaluated by separating different kinds of compounds, such as alkylbenzenes, thiourea and its analogues, and amino acids. The lowest plate height of ~6.8 μm was obtained, which corresponded to column efficiency (theoretical plates, N) of ~147,000 plates m(-1) for thiourea. ILs, as a new type of functional monomer, present a promising option in the fabrication of the organic polymer-based monolithic columns in CEC. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Invasive plants on disturbed Korean sand dunes

    Science.gov (United States)

    Kim, Kee Dae

    2005-01-01

    The sand dunes in coastal regions of South Korea are important ecosystems because of their small size, the rare species found in this habitat, and the beautiful landscapes they create. This study investigated the current vegetative status of sand dunes on three representative coasts of the Korean peninsula, and on the coasts of Cheju Island, and assessed the conditions caused by invasive plants. The relationships between the degree of invasion and 14 environmental variables were studied. Plots of sand dunes along line transects perpendicular to the coastal lines were established to estimate vegetative species coverage. TWINSPAN (Two-Way Indicator Species Analysis), CCA (Canonical Correspondence Analysis), and DCCA (Detrended Canonical Correspondence Analysis) were performed to classify communities on sand dunes and assess species composition variation. Carex kobomugi, Elymus mollis, and Vitex rotundifolia were found to be the dominant species plotted on the east, the west, and the peripheral coasts of Cheju Island, respectively. Vegetation on the south coast was totally extinct. The 19 communities, including representative C. kobomugi, C. kobomugi- Ixeris repens, C. kobomugi- Oenothera biennis, E. mollis, Lolium multiflorum- Calystegia soldanella, and V. rotundifolia- C. kobomugi, were all classified according to TWINSPAN. Oenothera biennis and L. multiflorum were exotics observed within these native communities. CCA showed that invasive native and exotic species distribution was segregated significantly, according to disturbance level, exotic species number, gravel, sand and silt contents, as well as vegetation size. It further revealed that human disturbance can strongly favor the settlement of invasive and exotic species. Restoration options to reduce exotic plants in the South Korean sand dune areas were found to be the introduction of native plant species from one sand dune into other sand dune areas, prohibition of building and the introduction of exotic

  18. Characteristics of SCC with Fly Ash and Manufactured Sand

    Science.gov (United States)

    Praveen Kumar, K.; Radhakrishna

    2016-09-01

    Self compacting concrete (SCC) of M40 grade was designed. The binder in SCC consists of OPC and fly ash in the ratio of 65:35. River sand was replaced by manufactured sand (M-sand) at replacement levels of 20,40,60,80 and 100%. An attempt was made to evaluate the workability and strength characteristics of self compacting concrete with river sand and manufactured sand as fine aggregates. For each replacement level, constant workability was maintained by varying the dosage of superplasticizer. T50 flow time, V Funnel time, V-funnel T5 time as well as compressive, split tensile and flexural strength of SCC were found at each replacement level of M-sand. They were compared to SCC with river sand. Results indicate favourable use of M-sand in preparation of Self Compacting Concrete.

  19. Properties of dune sand concrete containing coffee waste

    Directory of Open Access Journals (Sweden)

    Mohamed Guendouz

    2018-01-01

    Full Text Available In the last years, an increase of coffee beverages consumption has been observed all over the world; and its consumption increases the waste coffee grounds which will become an environmental problems. Recycling of this waste to produce new materials like sand concrete appears as one of the best solutions for reduces the problem of pollution. This work aims to study the possibility of recycling waste coffee grounds (Spent Coffee Grounds (SCG as a fine aggregate by replacing the sand in the manufacturing of dune sand concrete. For this; sand concrete mixes were prepared with substitution of sand with the spent coffee grounds waste at different percentage (0%, 5%, 10%, 15% and 20% by volume of the sand in order to study the influence of this wastes on physical (Workability, bulk density and porosity, mechanical (compressive and flexural strength and Thermal (Thermal conductivity and thermal diffusivity properties of dune sand concrete. The results showed that the use of spent coffee grounds waste as partial replacement of natural sand contributes to reduce workability, bulk density and mechanical strength of sand concrete mixes with an increase on its porosity. However, the thermal characteristics are improved and especially for a level of 15% and 20% of substitution. So, it is possible to obtain an insulating material which can be used in the various types of structural components. This study ensures that reusing of waste coffee grounds in dune sand concrete gives a positive approach to reduce the cost of materials and solve some environmental problems.

  20. Microwave assisted solvent extraction and coupled-column reversed-phase liquid chromatography with UV detection use of an analytical restricted-access-medium column for the efficient multi-residue analysis of acidic pesticides in soils.

    Science.gov (United States)

    Hogendoom, E A; Huls, R; Dijkman, E; Hoogerbrugge, R

    2001-12-14

    A screening method has been developed for the determination of acidic pesticides in various types of soils. Methodology is based on the use of microwave assisted solvent extraction (MASE) for fast and efficient extraction of the analytes from the soils and coupled-column reversed-phase liquid chromatography (LC-LC) with UV detection at 228 nm for the instrumental analysis of uncleaned extracts. Four types of soils, including sand, clay and peat, with a range in organic matter content of 0.3-13% and ten acidic pesticides of different chemical families (bentazone, bromoxynil, metsulfuron-methyl, 2,4-D, MCPA, MCPP, 2,4-DP, 2,4,5-T, 2,4-DB and MCPB) were selected as matrices and analytes, respectively. The method developed included the selection of suitable MASE and LC-LC conditions. The latter consisted of the selection of a 5-microm GFF-II internal surface reversed-phase (ISRP, Pinkerton) analytical column (50 x 4.6 mm, I.D.) as the first column in the RAM-C18 configuration in combination with an optimised linear gradient elution including on-line cleanup of sample extracts and reconditioning of the columns. The method was validated with the analysis of freshly spiked samples and samples with aged residues (120 days). The four types of soils were spiked with the ten acidic pesticides at levels between 20 and 200 microg/kg. Weighted regression of the recovery data showed for most analyte-matrix combinations, including freshly spiked samples and aged residues, that the method provides overall recoveries between 60 and 90% with relative standard deviations of the intra-laboratory reproducibility's between 5 and 25%; LODs were obtained between 5 and 50 microg/kg. Evaluation of the data set with principal component analysis revealed that the parameters (i) increase of organic matter content of the soil samples and (ii) aged residues negatively effect the recovery of the analytes.

  1. Documenting the global impacts of beach sand mining

    Science.gov (United States)

    Young, R.; Griffith, A.

    2009-04-01

    For centuries, beach sand has been mined for use as aggregate in concrete, for heavy minerals, and for construction fill. The global extent and impact of this phenomenon has gone relatively unnoticed by academics, NGOs, and major news sources. Most reports of sand mining activities are found at the very local scale (if the mining is ever documented at all). Yet, sand mining in many localities has resulted in the complete destruction of beach (and related) ecosystems along with severe impacts to coastal protection and tourism. The Program for the Study of Developed Shorelines at Western Carolina University and Beachcare.org have initiated the construction of a global database of beach sand mining activities. The database is being built through a combination of site visits and through the data mining of media resources, peer reviewed papers, and reports from private and governmental entities. Currently, we have documented sand mining in 35 countries on 6 continents representing the removal of millions of cubic meters of sand. Problems extend from Asia where critical infrastructure has been disrupted by sand mining to the Caribbean where policy reform has swiftly followed a highly publicized theft of sand. The Program for the Study of Developed Shorelines recently observed extensive sand mining in Morocco at the regional scale. Tens of kilometers of beach have been stripped of sand and the mining continues southward reducing hope of a thriving tourism-based economy. Problems caused by beach sand mining include: destruction of natural beaches and the ecosystems they protect (e.g. dunes, wetlands), habitat loss for globally important species (e.g. turtles, shorebirds), destruction of nearshore marine ecosystems, increased shoreline erosion rates, reduced protection from storms, tsunamis, and wave events, and economic losses through tourist abandonment and loss of coastal aesthetics. The threats posed by sand mining are made even more critical given the prospect of a

  2. Studies on various characteristics of concrete structures using crushed sand

    International Nuclear Information System (INIS)

    Mimatsu, Makoto; Sugita, Hideaki; Yonemura, Masataka.

    1985-01-01

    With the recent advances of construction industry, the demands for concrete, hence for aggregate, are rising. The sand as such is in extreme shortage due to the exhaustion of river sand. Under the situation, the recent trends are for the use of crushed sand, i.e. the artificial sand obtained by crushing rocks, which have advantages of stabilized quality and adequate supplies. In building of nuclear power plants requiring large amounts of concrete, the usage of crushed sand is now unavoidable. The following are described : the situation of aggregate in Kyushu. production method of crushed sand and the quality standards, rocks used for crushed stone and sand and the properties, quality survey on crushed sand and the basic tests, characteristic tests of crushed-stone and -sand mixed concrete, the application of crushed sand in structures of the Sendai Nuclear Power Station. (Mori, K.)

  3. The development of an integrated IT system at Albian Sands Energy

    Energy Technology Data Exchange (ETDEWEB)

    Michaud, L. H. [Albian Sands Energy Inc., Fort McMurray, AB (Canada)

    2003-01-01

    Factors considered in the selection, implementation and integration of computer applications in an oil sands surface mining and extraction operation are discussed. The company's objective in choosing the system was to optimize the use of information and to meet technical, business and information technology requirements. In a departure from typical practice where the system is selected by the information technology team, with minimal input from the technical and business units, in the case of Albian Sands Energy the company's technical and business people were closely involved in the selection process. Integration of the system was a primary consideration, including linking all applications through a data warehouse and electronic data management system. Details of the applications architecture, construction of the applications inventory, selection of the applications, identification of integration requirements, project management issues, and benefits of an integrated system are described. 6 refs., 2 tabs., 1 fig.

  4. Design and development of 3 MeV, 30 kW DC industrial electron accelerator at Electron Beam Centre, Kharghar

    International Nuclear Information System (INIS)

    Mittal, K.C.; Nanu, K.; Jain, A.

    2006-01-01

    High power electron beam accelerators are becoming an important tool for industrial radiation process applications. Keeping this in mind, a 3 MeV, 10 mA, 30 kW DC industrial electron accelerator has been designed and is in advanced stage of development at Electron Beam Center, Kharghar, Navi Mumbai. The operating range of this accelerator is 1 MeV to 3 MeV with maximum beam current of 10 mA. Electron beam at 5 keV is generated in electron gun with LaB 6 cathode and is injected into accelerating column at a vacuum of 10 -7 torr. After acceleration the beam is scanned and taken out in air through a 100 cm X 7 cm titanium window for radiation processing applications. The high voltage accelerating power supply is based on a capacitive coupled parallel fed voltage multiplier scheme operating at 120 kHz. A 50 kW oscillator feeds power to high voltage multiplier column. The electron gun, accelerating column and high voltage multiplier column are housed in accelerator tank filled with SF 6 gas insulation at 6 kg/cm 2 . The accelerator is located in a RCC building with product conveyor for handling products. A central computerized control system is adopted for operation of the accelerator. Accelerator is in the advance stage of commissioning. Many of the subsystems have been commissioned and tested. This paper describes the design details and current status of the accelerator and various subsystems. (author)

  5. Stable isotope probing and dynamic loading experiments provide insight into the ecophysiology of novel ammonia oxidizers in rapid gravity sand filters

    DEFF Research Database (Denmark)

    Fowler, Jane; Palomo, Alejandro; Gülay, Arda

    to elucidate the differences in ecophysiology between the ammonia oxidizing clades that enable them to co-exist in this unique environment. Experiments were conducted using sand columns designed and operated to mimic the conditions in the full-scale parent RSF. RNA and DNA stable isotope probing based on 13C......-bicarbonate incorporation during continuous feeding with either ammonium or nitrite as sole energy source implicated Nitrospira spp. and certain ‘heterotrophic’ bacteria in addition to Nitrosomonas spp. in autotrophy during ammonium oxidation in RSFs. Further experimentation aimed to elucidate the ecophysiology of each...

  6. Depth dependent microbial carbon use efficiency in the capillary fringe as affected by water table fluctuations in a column incubation experiment

    Science.gov (United States)

    Pronk, G. J.; Mellage, A.; Milojevic, T.; Smeaton, C. M.; Rezanezhad, F.; Van Cappellen, P.

    2017-12-01

    Microbial growth and turnover of soil organic carbon (SOC) depend on the availability of electron donors and acceptors. The steep geochemical gradients in the capillary fringe between the saturated and unsaturated zones provide hotspots of soil microbial activity. Water table fluctuations and the associated drying and wetting cycles within these zones have been observed to lead to enhanced turnover of SOC and adaptation of the local microbial communities. To improve our understanding of SOC degradation under changing moisture conditions, we carried out an automated soil column experiment with integrated of hydro-bio-geophysical monitoring under both constant and oscillating water table conditions. An artificial soil mixture composed of quartz sand, montmorillonite, goethite and humus was used to provide a well-defined system. This material was inoculated with a microbial community extracted from a forested riparian zone. The soils were packed into 6 columns (60 cm length and 7.5 cm inner diameter) to a height of 45 cm; and three replicate columns were incubated under constant water table while another three were saturated and drained monthly. The initial soil development, carbon cycling and microbial community development were then characterized during 10 months of incubation. This system provides an ideal artificial gradient from the saturated to the unsaturated zone to study soil development from initially homogeneous materials and the same microbial community composition under controlled conditions. Depth profiles of SOC and microbial biomass after 329 days of incubation showed a depletion of carbon in the transition drying and wetting zone that was not associated with higher accumulation of microbial biomass, indicating a lower carbon use efficiency of the microbial community established within the water table fluctuation zone. This was supported by a higher ATP to microbial biomass carbon ratio within the same zone. The findings from this study highlight the

  7. Optimization and simulation of tandem column supercritical fluid chromatography separations using column back pressure as a unique parameter.

    Science.gov (United States)

    Wang, Chunlei; Tymiak, Adrienne A; Zhang, Yingru

    2014-04-15

    Tandem column supercritical fluid chromatography (SFC) has demonstrated to be a useful technique to resolve complex mixtures by serially coupling two columns of different selectivity. The overall selectivity of a tandem column separation is the retention time weighted average of selectivity from each coupled column. Currently, the method development merely relies on extensive screenings and is often a hit-or-miss process. No attention is paid to independently adjust retention and selectivity contributions from individual columns. In this study, we show how tandem column SFC selectivity can be optimized by changing relative dimensions (length or inner diameter) of the coupled columns. Moreover, we apply column back pressure as a unique parameter for SFC optimization. Continuous tuning of tandem column SFC selectivity is illustrated through column back pressure adjustments of the upstream column, for the first time. In addition, we show how and why changing coupling order of the columns can produce dramatically different separations. Using the empirical mathematical equation derived in our previous study, we also demonstrate a simulation of tandem column separations based on a single retention time measurement on each column. The simulation compares well with experimental results and correctly predicts column order and back pressure effects on the separations. Finally, considerations on instrument and column hardware requirements are discussed.

  8. Influence of sand base preparation on properties of chromite moulding sands with sodium silicate hardened with selected methods

    Directory of Open Access Journals (Sweden)

    Stachowicz M.

    2017-03-01

    Full Text Available The paper presents a research on the relation between thermal preparation of chromite sand base of moulding sands containing sodium silicate, hardened with selected physical and chemical methods, and structure of the created bonding bridges. Test specimens were prepared of chromite sand - fresh or baked at 950°C for 10 or 24 hours - mixed with 0.5 wt.% of the selected non-modified inorganic binder and, after forming, were hardened with CO2 or liquid esters, dried traditionally or heated with microwaves at 2.45 GHz. It was shown on the grounds of SEM observations that the time of baking the base sand and the hardening method significantly affect structure of the bonding bridges and are correlated with mechanical properties of the moulding sands. It was found that hardening chromite-based moulding mixtures with physical methods is much more favourable than hardening with chemical methods, guaranteeing also more than ten times higher mechanical properties.

  9. Experimental perforation of tubing with a hydraulic sand jet

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, Yu V

    1970-01-01

    A series of field tests has shown that perforation with a hydraulic sand jet improves the quality of well completion. The sand jet does not crack the cement sheath or the casing, and the perforations are larger and deeper than perforations formed by explosive charges. Fluid circulation during sand jet perforation can safely be stopped for at least 10 min. Water containing a surfactant can be used as a sand carrier. Sand jet perforation allows successful completion of wells cased by 2 tubing strings. Sand jet perforation can be used to clean the borehole well and to remove foreign objects from the well.

  10. Effect of manufactured sand on the durability characteristics of concrete

    Directory of Open Access Journals (Sweden)

    S. S. SARAVANAN

    2016-12-01

    Full Text Available Concrete is the most sought after material due to increase in construction activities and infrastructural developments. Availability of natural sand is decreasing thereby increase in the cost of construction. In the present work undertaken, an attempt has been made to give an alternative to natural sand. Optimization of replacement of natural sand with manufactured sand in concrete, durability studies such as water absorption, rapid chloride permeability test, sorptivity, acid resistance, alkaline resistance, impact resistance and abrasion resistance of M40 and M50 grades of concrete have been studied with manufactured sand as fine aggregate and compared the results with the conventional sand concrete. The results shows that there is an increase in the durability properties up to 70 % level of replacements of sand with manufactured sand as fine aggregate and for 100 % use of manufactured sand also gives the better durability than the conventional sand concrete.

  11. Experimental Study on Superfine Sand Concrete Mixed by Double Mixing Technology

    OpenAIRE

    yuqing zhao

    2013-01-01

    Traditional concept thought that medium sand and fine sand can be used to mix concrete, superfine sand can not used to mix concrete. This makes the source of superfine sand limited. With the shortage of medium sand and fine sand, it is imperative to exploit the resource of superfine sand. Superfine sand concrete is mixed by means of Double-doped Technology-ultra-fine fly ash and super plasticizer. Primary factor influencing superfine sand concrete strength is studied by orthogonal test, the o...

  12. The physics of wind-blown sand and dust.

    Science.gov (United States)

    Kok, Jasper F; Parteli, Eric J R; Michaels, Timothy I; Karam, Diana Bou

    2012-10-01

    The transport of sand and dust by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This paper presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.

  13. Sand Dunes with Frost

    Science.gov (United States)

    2004-01-01

    9 May 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a suite of frost-covered sand dunes in the north polar region of Mars in early spring, 2004. The dunes indicate wind transport of sand from left to right (west to east). These landforms are located near 78.1oN, 220.8oW. This picture is illuminated by sunlight from the lower left and covers an area about 3 km (1.9 mi) across.

  14. Development of a 130-mA, 75-kV high voltage column for high-intensity dc proton injectors

    International Nuclear Information System (INIS)

    Sherman, J.; Arvin, A.; Hansborough, L.; Hodgkins, D.; Meyer, E.; Schneider, J.D.; Stevens, R.R. Jr.; Zaugg, T.

    1997-01-01

    A reliable high-voltage (HV) column has been developed for dc proton injectors with applications to high-intensity cw linacs. The HV column is coupled with a microwave-driven plasma generator to produce a 75-keV, 110-mA dc proton beam. Typical proton fraction from this source is 85--90%, requiring the HV column and accelerating electrodes to operate with a 130-mA hydrogen-ion beam current. A glow-discharge, which was caused by the ion source axial magnetic field, was initially observed in the HV column. This problem was solved by scaling the electron production processes, the magnetic field, and the HV column pressure into a favorable regime. A subsequent 168 hour reliability run on the 75-keV injector showed that the ion source (plasma generator and HV column) has >98% beam availability

  15. Gas Chromatograph Method Optimization Trade Study for RESOLVE: 20-meter Column v. 8-meter Column

    Science.gov (United States)

    Huz, Kateryna

    2014-01-01

    RESOLVE is the payload on a Class D mission, Resource Prospector, which will prospect for water and other volatile resources at a lunar pole. The RESOLVE payload's primary scientific purpose includes determining the presence of water on the moon in the lunar regolith. In order to detect the water, a gas chromatograph (GC) will be used in conjunction with a mass spectrometer (MS). The goal of the experiment was to compare two GC column lengths and recommend which would be best for RESOLVE's purposes. Throughout the experiment, an Inficon Fusion GC and an Inficon Micro GC 3000 were used. The Fusion had a 20m long column with 0.25mm internal diameter (Id). The Micro GC 3000 had an 8m long column with a 0.32mm Id. By varying the column temperature and column pressure while holding all other parameters constant, the ideal conditions for testing with each column length in their individual instrument configurations were determined. The criteria used for determining the optimal method parameters included (in no particular order) (1) quickest run time, (2) peak sharpness, and (3) peak separation. After testing numerous combinations of temperature and pressure, the parameters for each column length that resulted in the most optimal data given my three criteria were selected. The ideal temperature and pressure for the 20m column were 95 C and 50psig. At this temperature and pressure, the peaks were separated and the retention times were shorter compared to other combinations. The Inficon Micro GC 3000 operated better at lower temperature mainly due to the shorter 8m column. The optimal column temperature and pressure were 70 C and 30psig. The Inficon Micro GC 3000 8m column had worse separation than the Inficon Fusion 20m column, but was able to separate water within a shorter run time. Therefore, the most significant tradeoff between the two column lengths was peak separation of the sample versus run time. After performing several tests, it was concluded that better

  16. Relationships between sand and water quality at recreational beaches.

    Science.gov (United States)

    Phillips, Matthew C; Solo-Gabriele, Helena M; Piggot, Alan M; Klaus, James S; Zhang, Yifan

    2011-12-15

    Enterococci are used to assess the risk of negative human health impacts from recreational waters. Studies have shown sustained populations of enterococci within sediments of beaches but comprehensive surveys of multiple tidal zones on beaches in a regional area and their relationship to beach management decisions are limited. We sampled three tidal zones on eight South Florida beaches in Miami-Dade and Broward counties and found that enterococci were ubiquitous within South Florida beach sands although their levels varied greatly both among the beaches and between the supratidal, intertidal and subtidal zones. The supratidal sands consistently had significantly higher (p sand) than the other two zones. Levels of enterococci within the subtidal sand correlated with the average level of enterococci in the water (CFU/100mL) for the season during which samples were collected (r(s) = 0.73). The average sand enterococci content over all the zones on each beach correlated with the average water enterococci levels of the year prior to sand samplings (r(s) = 0.64) as well as the average water enterococci levels for the month after sand samplings (r(s) = 0.54). Results indicate a connection between levels of enterococci in beach water and sands throughout South Florida's beaches and suggest that the sands are one of the predominant reservoirs of enterococci impacting beach water quality. As a result, beaches with lower levels of enterococci in the sand had fewer exceedences relative to beaches with higher levels of sand enterococci. More research should focus on evaluating beach sand quality as a means to predict and regulate marine recreational water quality. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Compressive Strength of Compacted Clay-Sand Mixes

    Directory of Open Access Journals (Sweden)

    Faseel Suleman Khan

    2014-01-01

    Full Text Available The use of sand to improve the strength of natural clays provides a viable alternative for civil infrastructure construction involving earthwork. The main objective of this note was to investigate the compressive strength of compacted clay-sand mixes. A natural clay of high plasticity was mixed with 20% and 40% sand (SP and their compaction and strength properties were determined. Results indicated that the investigated materials exhibited a brittle behaviour on the dry side of optimum and a ductile behaviour on the wet side of optimum. For each material, the compressive strength increased with an increase in density following a power law function. Conversely, the compressive strength increased with decreasing water content of the material following a similar function. Finally, the compressive strength decreased with an increase in sand content because of increased material heterogeneity and loss of sand grains from the sides during shearing.

  18. Small Column Ion Exchange

    International Nuclear Information System (INIS)

    Huff, Thomas

    2010-01-01

    Small Column Ion Exchange (SCIX) leverages a suite of technologies developed by DOE across the complex to achieve lifecycle savings. Technologies are applicable to multiple sites. Early testing supported multiple sites. Balance of SRS SCIX testing supports SRS deployment. A forma Systems Engineering Evaluation (SEE) was performed and selected Small Column Ion Exchange columns containing Crystalline Silicotitanate (CST) in a 2-column lead/lag configuration. SEE considered use of Spherical Resorcinol-Formaldehyde (sRF). Advantages of approach at SRS include: (1) no new buildings, (2) low volume of Cs waste in solid form compared to aqueous strip effluent; and availability of downstream processing facilities for immediate processing of spent resin.

  19. Controls on the abruptness of gravel-sand transitions

    Science.gov (United States)

    Venditti, J. G.; Church, M. A.; Lamb, M. P.; Domarad, N.; Rennie, C. D.

    2014-12-01

    As gravel-bedded rivers fine downstream, they characteristically exhibit an abrupt transition from gravel- to sand-bed. This is the only abrupt transition in grain-size that occurs in the fluvial system and has attracted considerable attention. A number of competing theories have been proposed to account for the abruptness of the transition, including base-level control, attrition of ~10mm gravel to produce sand, and sediment sorting processes. The prevailing theory for the emergence of abrupt transitions is size selective sorting of bimodal sediment wherein gravel deposits due to downstream declining shear stress, fining the bedload until a sand-bed emerges. We explored this hypothesis by examining grain-size, shear stress, gravel mobility and sand suspension thresholds through the gravel-sand transition (GST) of the Fraser River, British Columbia. The Fraser GST is an arrested gravel wedge with patches of gravel downstream of the wedge forming a diffuse extension. There is an abrupt change in bed slope through the transition that leads to an abrupt change in shear stress. The GST, bed-slope change and backwater caused by the ocean are all coincident spatially, which enhances the sharpness of the GST. Interestingly, the bimodal reach of the river occurs downstream of the GST and exhibits no downstream gradients in shear stress, suspended sediment flux, gravel mobility or sand suspension thresholds. This calls into question the prevailing theory for the emergence of an abrupt GST by size selective sorting. We provide evidence, both empirical and theoretical, that suggests the emergence of an abrupt GST is caused by rapid deposition of sand when fine gravel deposits. We argue that the emergence of gravel-sand transitions is a consequence of gravel-bedded rivers adopting a steeper slope than sand-bedded rivers. The abruptness arises because the bed slope required to convey the gravel load fixes the distal location of a terminal gravel wedge, and once the river has

  20. Oil sands to the rescue: oil sand microbial communities can degrade recalcitrant alkyl phenyl alkanoic acids

    Energy Technology Data Exchange (ETDEWEB)

    Whitby, Corinne [University of Essex (Canada)], email: cwhitby@essex.ac.uk

    2011-07-01

    Almost half of all global oil reserves are found as biodegraded heavy oils found in vast tar sand deposits located in North and South America and these account for 47% of Canadian oil production. Oil sand extraction generates large amounts of toxic waste water, known as oil sand process waters (OSPW), that are stored in large tailing ponds that contain toxic compounds like naphthenic acids (NAs). The presence of NAs creates problems like toxicity, corrosion, and the formation of calcium napthenate deposits which block pipelines and other infrastructure and need to be removed. This paper presents oil sand microbial communities that can degrade these NAs. The approach is to apply new aliphatic and aromatic NAs as substrates to supplement and identify NA degrading microbes and also to identify the metabolites produced and explain NA degradation pathways and the functional genes involved. The chemistry and the processes involved are explained. From the results, it is suggested that pure cultures of P. putida KT2440 be used against NAs.

  1. Attenuation of pyrite oxidation with a fly ash pre-barrier: Reactive transport modelling of column experiments

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Lopez, R.; Cama, J.; Nieto, J.M.; Ayora, C.; Saaltink, M.W. [University of Huelva, Huelva (Spain). Dept. of Geology

    2009-09-15

    Conventional permeable reactive barriers (PRBs) for passive treatment of groundwater contaminated by acid mine drainage (AMD) use limestone as reactive material that neutralizes water acidity. However, the limestone-alkalinity potential ceases as inevitable precipitation of secondary metal-phases on grain surfaces occurs, limiting its efficiency. In the present study, fly ash derived from coal combustion is investigated as an alternative alkalinity generating material for the passive treatment of AMD using solution-saturated column experiments. Unlike conventional systems, the utilization of fly ash in a pre-barrier to intercept the non-polluted recharge water before this water reacts with pyrite-rich wastes is proposed. Chemical variation in the columns was interpreted with the reactive transport code RETRASO. In parallel, kinetics of fly ash dissolution at alkaline pH were studied using flow-through experiments and incorporated into the model. In a saturated column filled solely with pyritic sludge-quartz sand (1: 10), oxidation took place at acidic conditions (pH 3.7). According to SO{sub 4}{sup 2-} release and pH, pyrite dissolution occurred favourably in the solution-saturated porous medium until dissolved O{sub 2} was totally consumed. In a second saturated column, pyrite oxidation took place at alkaline conditions (pH 10.45) as acidity was neutralized by fly ash dissolution in a previous level. At this pH Fe release from pyrite dissolution was immediately depleted as Fe-oxy(hydroxide) phases that precipitated on the pyrite grains, forming Fe-coatings (microencapsulation). With time, pyrite microencapsulation inhibited oxidation in practically 97% of the pyritic sludge. Rapid pyrite-surface passivation decreased its reactivity, preventing AMD production in the relatively short term.

  2. Mass transfer model liquid phase catalytic exchange column simulation applicable to any column composition profile

    Energy Technology Data Exchange (ETDEWEB)

    Busigin, A. [NITEK USA Inc., Ocala, FL (United States)

    2015-03-15

    Liquid Phase Catalytic Exchange (LPCE) is a key technology used in water detritiation systems. Rigorous simulation of LPCE is complicated when a column may have both hydrogen and deuterium present in significant concentrations in different sections of the column. This paper presents a general mass transfer model for a homogenous packed bed LPCE column as a set of differential equations describing composition change, and equilibrium equations to define the mass transfer driving force within the column. The model is used to show the effect of deuterium buildup in the bottom of an LPCE column from non-negligible D atom fraction in the bottom feed gas to the column. These types of calculations are important in the design of CECE (Combined Electrolysis and Catalytic Exchange) water detritiation systems.

  3. Additive colours approach for dental ceramics translucency characteristics made from Sumatra and Java natural sands

    Science.gov (United States)

    Takarini, V.; Gunawan, J.; Hasratiningsih, Z.; Rudyawan, A.

    2018-04-01

    Translucency is one of dental ceramics desirable aesthetic characteristics, which can be used as an indirect restoration. Dental ceramics can also be made using Computed Aided Design/Computer Aided Manufacturing (CAD/CAM) unit that can create variety blocks as an ingot into a customized restoration. This paper presents the results of self-synthesized porcelain blocks generated from natural sand of Sumatera and Java Islands to promote national independency. This research aims to determine the translucency of dental ceramics made from Indonesia’s natural sand. Six samples each of two different synthesized temperatures, 1150 °C and 1200 °C, were made. To analyse translucency of the sample, their image was taken in bright light background in a black box, then additive green and blue colours histogram channel with range 0 (opaque) to 255 (transparent) were evaluated using Matlab R2015B. The result revealed that mean of green peaks on 1150 °C has an average translucency value of 41%, compared to 34% of blue peaks. Lower percentage of translucency, 31% and 25% on the green and blue channel respectively were attained in samples synthesized in 1200 °C. These suggest that 1150 °C is the optimum temperature for translucency for these ceramic samples from natural sands as they contain leucite crystals shown by the XRD analyses as a result of silica-undersaturated mixture indicated by the Electron Dispersive Spectroscopy. SEM (Scanning Electron Microscope) results show remnant of air pocket in the samples sintered at higher temperature.In conclusion, natural sand from Sumatera and Java can be considered as reliable, cheap basic material options in developing self-synthesized dental ceramics with a desirable translucency. These preliminary results indicate that better balance between strength and translucency could potentially be achieved by making nano-sized dental ceramics.

  4. Potential building sand deposits in Songkhla province area

    Directory of Open Access Journals (Sweden)

    Kooptarnond, K.

    2002-10-01

    Full Text Available An investigation of potential building sand deposits in Songkhla province area subdivided them into four regions according to their accumulation in various alluvial plains, meanders throughout alluvial deposits and residual soils. Four selected deposits, were Rattaphum-Khuan Niang, U-Taphao river, Na Mom, and Chana-Thepha regions. Information obtained from these deposits revealed a good correlation between the geomorphological features as interpreted from aerial photographs and those identified from vertical electrical resistivity sounding results. Sand samples were analysed for their physical and chemical properties. Petrographic studies were also undertaken to characterize the composition types, texture and shapes. An overview of the sand properties was used them to be within the acceptable limits for building sand. However, relatively high organic impurities and soundness were found in sand from Khuan Niang and Na Mom deposits. The result indicated a potential reconnaissance mineral resource of about 46 square kilometres.A reserve evaluation for natural building sand was carried out by using Geographic Information System (GIS. Maps of the various parameters considered were constructed in digital database format with the aid of Arc/Info and ArcView software. Overlay mapping and buffer zone modules were performed to evaluate inferred resources of building sand. The key parameters of analysis included the distance from transportation, distance from streams, lithology and thickness of sand layers. The remaining inferred sand total was of about 386 million cubic metres or about 1,021 million metric tons was therefore estimated, of which 60 percent lies in the Rattaphum-Khuan Niang region and 40 percent in the other regions.

  5. Stakeholder relations in the oil sands : managing uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-05-15

    Alberta's oil sands are now at the crossroads of a series of significant and complex global issues that will require careful negotiation by all stakeholders involved in the oil sands industry. This paper discussed methods of managing uncertainty and risk related to the oil sands industry's agenda for the future. Oil sands developers must continue to secure permission from communities and other key stakeholders in order to develop oil sand projects. Stakeholder relations between oil sands operators, First Nations, and Metis Nation communities must ensure that respect is maintained while environmental impacts are minimized and long-term economic benefits are secured for all parties. Environmental non-governmental organizations (ENGOs) must ensure that oil sands resources are developed responsibly, and that environmental standards are maintained. Seven key shifts in stakeholder relations resulting from the recent economic crisis were identified. These included (1) withdrawal from the multi-stakeholder process, (2) increased focus on government to demonstrate policy leadership, (3) a stronger push from ENGOs to express environmental concerns, (4) global lobby and public relations efforts from ENGOs, (5) companies retreating to local community stakeholders, (6) more active demands from First Nations and Metis Nations groups, and (7) companies challenging ENGO campaigns. The study concluded by suggesting that government leadership is needed to clear policy and regulatory frameworks for Canada's oil sands.

  6. Providing floating capabilities in latest-generation sand screens

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, E.G.; Coronado, M.P. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Baker Hughes, Houston, TX (United States)

    2008-10-15

    Alternative production methods are needed for the massive reserves located in the bitumen region of Canada's tar sands. The area has over 100 installations of sand screens/slotted liners in both injection and production legs using steam-assisted gravity drainage (SAGD) technology. Multiple wells must be drilled from a single pad because of the sensitive nature of the environment. With significant depths of these wells, a floating sand screen provides assurance that the sand screen will reach the desired depth. Paraffin is generally used to plug the flow access of the screen during installation. This paper discussed a new technology that has been developed to allow for sand screen installations without relying on paraffin wax to withstand differential pressure. The new technology uses a hydro-mechanical valving system incorporated into the screen design to temporarily close off the screen while being run in the hole. The paper described how the technology could provide a reliable, time-saving solution for SAGD installations when floating sand control screens are needed. The paper discussed current technology and its limitations, sand screen installation, screen design for floating applications, and additional applications. It was concluded that this technology solution provides a unique alternative to the methods currently used to install sand screens with SAGD technology in the fast growing Canadian market for bitumen recovery. 2 refs., 5 figs.

  7. Particle densities in a positive column He-I+ discharge

    International Nuclear Information System (INIS)

    Gato, T.

    1980-01-01

    In a positive column He-1 + laser discharge, the He + ion density has been determined directly from the absorption of the HeII 30.3 nm resonance line measured by a modified absorption method, and the electron density has been obtained using this measured He + ion density. The population densities of the upper and lower states of the 612.7 nm laser line have also been measured roughly. (orig.)

  8. Revegetation and management of tailings sand slopes from tar sand extraction: 1978 results

    Energy Technology Data Exchange (ETDEWEB)

    Rowell, M J

    1979-01-01

    The results are reported of research into the revegetation of two areas on a steeply sloping dike composed of tailings sand from tar sand extraction at the Great Canadian Oil Sand Limited plant at Fort McMurray, Alberta. One area was seeded with three pasture grasses and two legumes in 1971 after the slope surface had been mixed with peat to a depth of 15 cm. A second area had been amended with peat or peat and overburden and differing rates of fertilizer added. A mix containing nine grasses, four legumes, and oats, as a companion crop, was seeded in July 1976. The objectives of the research were to study methods for the establishment of a stable vegetative cover that would prevent erosion of the slope and, in time, might become a self maintaining unit. Tillage of soil amendments to a depth of 15 cm and 30 cm were compared in promoting deeper rooting and stabilizing of the slope.

  9. Developing new markets for oil sands products

    International Nuclear Information System (INIS)

    Crandall, G.

    2004-01-01

    This paper presents a review by Purvin and Gertz of western Canadian crude oil supply. This energy consulting firm provides advise to the energy sector. It suggests that oil sands production will surpass declining conventional production. Oil sands supply includes bitumen, synthetic crude oil (SCO), and diluent. It is forecasted that oil sands will increase from 42 per cent of western supply in 2002 to 78 per cent in 2015. The potential of Alberta's oil sands was discussed along with a recent study of refined products and petrochemicals from bitumen. Upgrading, refining and petrochemical case studies were presented. The author examined if a Canadian oil sands upgrading project with high capital costs can be competitive with competing projects in the United States and internationally. In addition to supply and demand issues, the presentation examined infrastructure capability and market potential in the United States. The economic potential and risks of preferred business cases compared to upgrading to SCO were also evaluated. 15 figs

  10. The behavior of gaseous iodine in sand

    International Nuclear Information System (INIS)

    Takahashi, Kanji

    1974-01-01

    Radioactive iodine gas was passed through 10 different sands collected at rivers and hills. The relation between the amount of the loaded gas and the amount of adsorbed gas was determined at room temperature, 50 -- 60 0 C, and 90 -- 100 0 C under humidity of 2 sand. This amount was about 1 -- 3 times as much as that of monomolecular membrane adsorption, 0.2 -- 0.3 μg/cm 2 . The decrease of adsorption amount that accompanies the increase of humidity is attributable to the decrease of effective surface area of sand due to the presence of water. The transport of iodine in sand was studied by passing gaseous iodine through a glass tubing packed with sand. The distribution in the flow direction of iodine indicated that the ease of desorption depends upon the situation of adsorption. Easily desorbed case was named Henry type adsorption. Hardly desorbed case was named absorption type. Discussion is made on experimental results. (Fukutomi, T.)

  11. Two generalizations of column-convex polygons

    International Nuclear Information System (INIS)

    Feretic, Svjetlan; Guttmann, Anthony J

    2009-01-01

    Column-convex polygons were first counted by area several decades ago, and the result was found to be a simple, rational, generating function. In this work we generalize that result. Let a p-column polyomino be a polyomino whose columns can have 1, 2, ..., p connected components. Then column-convex polygons are equivalent to 1-convex polyominoes. The area generating function of even the simplest generalization, namely 2-column polyominoes, is unlikely to be solvable. We therefore define two classes of polyominoes which interpolate between column-convex polygons and 2-column polyominoes. We derive the area generating functions of those two classes, using extensions of existing algorithms. The growth constants of both classes are greater than the growth constant of column-convex polyominoes. Rather tight lower bounds on the growth constants complement a comprehensive asymptotic analysis.

  12. CHROMIUM(VI REDUCTION BY A MIXED CULTURE OF SULFATE REDUCING BACTERIA DEVELOPED IN COLUMN REACTOR

    Directory of Open Access Journals (Sweden)

    Cynthia Henny

    2008-03-01

    Full Text Available A lactate enriched mixed sulfate reducing bacteria (SRB culture was examined for the reduction of Cr(VI in a continuous flow system. The influent was mineral salts media added with lactate and sulfate with amounts of 8 and 6 mM respectively as electron donor and electron acceptor. The SRB culture was allowed to stabilize in the column before adding the Cr(VI to the influent. Chromium and sulfate reduction and lactate oxidation were examined by measuring the concentrations of Cr(Vl, sulfate and lactate in the influent and the effluent over time. The experiment was discontinued when Cr(VI concentration in the effiuent was breakthrough. In the absence of Cr(VI, sulfate was not completely reduced in the column, although lactate was completely oxidized and acetate as an intermediate product was not often detected. Almost all of Cr(VI loaded was reduced in the column seeded with the SRB culture at influent Cr(VI concentrations of 192,385 and769 mM. There was no significant Cr(VI loss in the control column, indicating that Cr(VI removal was due to the reduction of Cr(VI to Cr (lll by the SRB culture. The instantaneous Cr(VI removal decreased to a minimum of 32%, 24 days after the influent Cr(VI concentration was increased to 1540 mM, ancl sulfate removal efficiency decreased to a minimum of 17%. The SRB population in the column decreased 100 days after C(VI was added to the column. The total mass of Cr(VI reduced was approximately 878 mmol out of 881 mmol of Cr(Vl loaded in 116 days. The results clearly show that our developed SRB culture could reduced Cr(Vl considerably.

  13. Booming Sand Dunes

    Science.gov (United States)

    Vriend, Nathalie

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

  14. Oil sands economic impacts Canada : CERI report : backgrounder

    International Nuclear Information System (INIS)

    2005-09-01

    Oil sands production now accounts for 1 out of every 2 barrels of supply in Western Canada. It is anticipated that Alberta's oil sands sector will experience significant growth over the next few decades. This paper provided an outline of the challenges and economic impacts resulting from oil sands development in Canada. Alberta's oil sands reserves are estimated at 175 billion barrels that are deemed economically recoverable using current technology. At current production levels, reserves will sustain production of 2.5 million barrels per day for the next 200 years. A study by the Canadian Energy Research Institute (CERI) has forecast $100 billion in investment for the 2000-2020 period. Numerous companies hold leases and are planning new projects. A number of recent advances in oil sands technology are expected to further reduce costs as development matures. A royalty and tax regime that provides long-term fiscal certainty is a key factor that supports current oil sands growth forecasts. The CERI study has indicated that economic spinoffs from oil sands development relate to employment generated outside of Alberta, and that the largest percentage of government revenue accrues to the federal government. However, development may be constrained because the pace of growth in the sector may exceed underlying infrastructure related to roads, housing and municipal services. An adequate workforce of qualified trades and technical and professional people is also crucial. Several pipeline projects have been proposed to deliver oil sands crudes to new markets over the next decade. It was concluded that the billions of dollars invested in oil sands in Alberta will contribute to the economic prosperity of the entire country. 11 figs

  15. Strength and Microstructure of Concrete with Iron Ore Tailings as Replacement for River Sand

    Directory of Open Access Journals (Sweden)

    Umara Shettima Ali

    2018-01-01

    Full Text Available River Sand is one of the basic ingredients used in the production of concrete. Consequently, continuous consumption of sand in construction industry contributes significantly to depletion of natural resources. To achieve more sustainable construction materials, this paper reports the use of iron ore tailings (IOT as replacement for river sand in concrete production. IOT is a waste product generated from the production of iron ore and disposed to land fill without any economic value. Concrete mixtures containing different amount of IOT were designed for grade C30 with water to cement ratio of 0.60. The percentage ratios of the river sand replacements by IOT were 25%, 50%, 75% and 100%. Concrete microstructure test namely, XRD and Field Emission Scanned Electron Microscopic/Energy dispersive X-ray Spectroscopy (FESEM/EDX were conducted for control and IOT concretes in order to determine the interaction and performance of the concrete containing IOT. Test results indicated that the slump values of 130 mm and 80 to 110 mm were recorded for the control and IOT concretes respectively. The concrete sample of 50% IOT recorded the highest compressive strength of 37.7 MPa at 28 days, and the highest flexural strength of 5.5 MPa compared to 4.7 MPa for reference concrete. The texture of the IOT is rough and angular which was able to improve the strength of the concrete.

  16. Strength and Microstructure of Concrete with Iron Ore Tailings as Replacement for River Sand

    Science.gov (United States)

    Umara Shettima, Ali; Ahmad, Yusof; Warid Hussin, Mohd; Zakari Muhammad, Nasiru; Eziekel Babatude, Ogunbode

    2018-03-01

    River Sand is one of the basic ingredients used in the production of concrete. Consequently, continuous consumption of sand in construction industry contributes significantly to depletion of natural resources. To achieve more sustainable construction materials, this paper reports the use of iron ore tailings (IOT) as replacement for river sand in concrete production. IOT is a waste product generated from the production of iron ore and disposed to land fill without any economic value. Concrete mixtures containing different amount of IOT were designed for grade C30 with water to cement ratio of 0.60. The percentage ratios of the river sand replacements by IOT were 25%, 50%, 75% and 100%. Concrete microstructure test namely, XRD and Field Emission Scanned Electron Microscopic/Energy dispersive X-ray Spectroscopy (FESEM/EDX) were conducted for control and IOT concretes in order to determine the interaction and performance of the concrete containing IOT. Test results indicated that the slump values of 130 mm and 80 to 110 mm were recorded for the control and IOT concretes respectively. The concrete sample of 50% IOT recorded the highest compressive strength of 37.7 MPa at 28 days, and the highest flexural strength of 5.5 MPa compared to 4.7 MPa for reference concrete. The texture of the IOT is rough and angular which was able to improve the strength of the concrete.

  17. Evaluation of distribution coefficients for the prediction of strontium and cesium migration in a uniform sand

    International Nuclear Information System (INIS)

    Reynolds, W.D.; Gillham, R.W.; Cherry, J.A.

    1982-01-01

    The validity of using a distribution coefficient (Ksub(d)) in the mathematical prediction of strontium and cesium transport through uniform saturated sand was investigated by comparing measured breakthrough curves with curves of simulations using the advection-dispersion and the advection equations. Values for Ksub(d) were determined by batch equilibration tests and, indirectly, by fitting the mathematical model to breakthrough data from column experiments. Although the advection-dispersion equation accurately represented the breakthrough curves for two nonreactive solutes (chloride and tritium), neither it nor the advection equation provided close representations of the strontium and cesium curves. The simulated breakthrough curves for strontium and cesium were nearly symmetrical, whereas the data curves were very asymmetrical, with long tails. Column experiments with different pore-water velocities indicated that the shape of the normalized breakthrough curves was not sensitive to velocity. This suggests that the asymmetry of the measured curves was the result of nonlinear partitioning of the cations between the solid and liquid phases, rather than nonequilibrium effects. The results indicate that the distribution coefficient, when used in advection-dispersion models for prediction of the migration of strontium and cesium in field situations, can result in significant error

  18. Effect of substrate size on sympatric sand darter benthic habitat preferences

    Science.gov (United States)

    Thompson, Patricia A.; Welsh, Stuart A.; Rizzo, Austin A.; Smith, Dustin M.

    2017-01-01

    The western sand darter, Ammocrypta clara, and the eastern sand darter, A. pellucida, are sand-dwelling fishes that have undergone range-wide population declines, presumably owing to habitat loss. Habitat use studies have been conducted for the eastern sand darter, but literature on the western sand darter remains sparse. To evaluate substrate selection and preference, western and eastern sand darters were collected from the Elk River, West Virginia, one of the few remaining rivers where both species occur sympatrically. In the laboratory, individuals were given the choice to bury into five equally available and randomly positioned substrates ranging from fine sand to granule gravel (0.12–4.0 mm). The western sand darter selected for coarse and medium sand, while the eastern sand darter was more of a generalist selecting for fine, medium, and coarse sand. Substrate selection was significantly different (p = 0.02) between species in the same environment, where the western sand darter preferred coarser substrate more often compared to the eastern sand darter. Habitat degradation is often a limiting factor for many species of rare freshwater fish, and results from this study suggest that western and eastern sand darters may respond differently to variations in benthic substrate composition.

  19. Preparation of Affinity Column Based on Zr4+ Ion for Phosphoproteins Isolation

    International Nuclear Information System (INIS)

    Lee, Seon Mi; Bae, In Ae; Park, Jung Hyen; Kim, Tae Dong; Choi, Seong Ho

    2009-01-01

    This paper has described about preparation of Zr 4+ affinity column based on the poly(styreneco- glycidyl methacrylate) prepared by emulsion polymerization of styrene and glycidyl methacrylate in order to isolate phosphopeptide. The Zr 4+ ions were introduced after the phophonation of an epoxy group on polymeric microspheres. The successful preparation of Zr 4+ -immobilized polymeric microsphere stationary phase was confirmed through Fourier transform infrared spectra, optical microscopy, scanning electron microscopy, X-ray photoelectron spectra and inductively coupled plasma-atomic emission spectrometer. The separation efficiency for Zr 4+ affinity column prepared by slurry packing was tested to phosphonated casein and dephosphonated casein. The resolution time (min) of the phosphonated casein was higher than that of dephosphated casein for Zr 4+ affinity polymeric microsphere by liquid chromatography. This Zr 4+ affinity column can be used for isolation of phosphonated casein from casein using liquid chromatography

  20. Provenance and recycling of Arabian desert sand

    Science.gov (United States)

    Garzanti, Eduardo; Vermeesch, Pieter; Andò, Sergio; Vezzoli, Giovanni; Valagussa, Manuel; Allen, Kate; Kadi, Khalid A.; Al-Juboury, Ali I. A.

    2013-05-01

    This study seeks to determine the ultimate origin of aeolian sand in Arabian deserts by high-resolution petrographic and heavy-mineral techniques combined with zircon U-Pb geochronology. Point-counting is used here as the sole method by which unbiased volume percentages of heavy minerals can be obtained. A comprehensive analysis of river and wadi sands from the Red Sea to the Bitlis-Zagros orogen allowed us to characterize all potential sediment sources, and thus to quantitatively constrain provenance of Arabian dune fields. Two main types of aeolian sand can be distinguished. Quartzose sands with very poor heavy-mineral suites including zircon occupy most of the region comprising the Great Nafud and Rub' al-Khali Sand Seas, and are largely recycled from thick Lower Palaeozoic quartzarenites with very minor first-cycle contributions from Precambrian basement, Mesozoic carbonate rocks, or Neogene basalts. Instead, carbonaticlastic sands with richer lithic and heavy-mineral populations characterize coastal dunes bordering the Arabian Gulf from the Jafurah Sand Sea of Saudi Arabia to the United Arab Emirates. The similarity with detritus carried by the axial Tigris-Euphrates system and by transverse rivers draining carbonate rocks of the Zagros indicates that Arabian coastal dunes largely consist of far-travelled sand, deposited on the exposed floor of the Gulf during Pleistocene lowstands and blown inland by dominant Shamal northerly winds. A dataset of detrital zircon U-Pb ages measured on twelve dune samples and two Lower Palaeozoic sandstones yielded fourteen identical age spectra. The age distributions all show a major Neoproterozoic peak corresponding to the Pan-African magmatic and tectonic events by which the Arabian Shield was assembled, with minor late Palaeoproterozoic and Neoarchean peaks. A similar U-Pb signature characterizes also Jafurah dune sands, suggesting that zircons are dominantly derived from interior Arabia, possibly deflated from the Wadi al

  1. The Geodiversity in Drift Sand Landscapes of The Netherlands

    Science.gov (United States)

    van den Ancker, Hanneke; Jungerius, Pieter Dirk; Riksen, Michel

    2015-04-01

    The authors carried out detailed field studies of more than twelve drift sand landscapes in The Netherlands. The objective of these studies was to restore Natura-2000 values by restoring the wind activity. Active drift sands occur almost exclusively in The Netherlands, Natura 2000 habitat 2330 'Inland dunes with open Corynephorus and Agrostis grasslands', for which reason our country is largely responsible for this European landscape. Active drift sands had almost disappeared for two reasons: first, the stabilization of the drift sands by air pollution, mainly nitrogen, which stimulates the growth of algae and grasses that initiate soil formation, and second, by the growth of forests surrounding the sands, which decreases the wind force. The restoration studies revealed differences in the geodiversity between and within the drift sand areas. Whereas the drift sands on geological and soil maps show as almost homogenous areas, they have in fact highly variable geo-conditions of which examples will be given. These geodiversity aspects concern differences in geomorphological structure, origin, sediments and age of the drift sands. Differences in wind and water erosion, trampling and soil formation add to the geodiversity within the drift sand areas. Especially in the primary stages of succession the differences in geodiversity are relevant for the Natura-2000 values. We discerned three main types of active sands. Firstly, the impressive drift sands with large parabolic dune structures, often consisting of series of interlocking parabolic dunes. They developed from the northeast towards the southwest, against the direction of the dominant wind, and must have taken centuries to develop. Small parts of these systems are still active, other parts show different degrees of soil formation. Their origin is still unclear but probably dates from medieval times (Heidinga, 1985, Jungerius & Riksen, 2008). Second are the drift sand areas with irregular hills from 0.5 to about 2

  2. Diffusion Processes in the Positive Column in a longitudinal magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Lehnert, B [Royal Institute of Technology, Stockholm (Sweden)

    1958-07-01

    The purpose of the present investigation is to study diffusion across a magnetic field in a configuration which is free from short-circuiting effects such as those described by Simon. It provides the possibility of deciding whether collision or 'drain' diffusion is operative. For the purpose a long cylindrical plasma column with a homogeneous magnetic field along the axis has been chosen. The theoretical treatment is given. On the basis of the collision diffusion theory Tonks, Rokhlin, Cummings and Tonks and Fataliev have pointed out that a longitudinal magnetic field will reduce the losses of particles to the walls. Consequently, when the magnetic field is present, a lower electron temperature and a smaller potential drop along the plasma column should be required to sustain a certain ion density. The present experiment forms an extension of that of Bickerton and von Engel into a range where the Schottky theory is applicable in the absence of a magnetic field and where the applied magnetic field is still made strong enough to influence the electron temperature.

  3. PHOTOGRAMMETRIC APPROACH IN DETERMINING BEAM-COLUMN CONNECTION DEFORMATIONS

    Directory of Open Access Journals (Sweden)

    Ali Koken

    Full Text Available In accordance with the advances in technology, displacement calculation techniques are ever developing. Photogrammetry has become preferable in some new disciplines with the advances in the image processing methods. In this study, the authors have used two different measurement techniques to determine the angles of rotation in beam-column connections that are subjected to reversible cyclic loading. The first of these is the method that is widely used, the conventional method in structural mechanics experiments, where Linear Variable Differential Transformers (LVDTs are utilized; and the second is the photogrammetric measurement technique. The rotation angles were determined using these techniques in a total of ten steel beam-column connection experiments. After discussing the test procedures of the aforementioned methods, the results were presented. It was observed that the rotation angles measured by each method were very close to each other. It was concluded that the photogrammetric measurement technique could be used as an alternative to conventional methods, where electronic LVDTs are used.

  4. Reversed preparation of low-density poly(divinylbenzene/styrene) foam columns coated with gold films

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Yinhai; Wang, Ni; Li, Yaling; Yao, Mengqi; Gan, Haibo; Hu, Wencheng, E-mail: huwc@uestc.edu.cn

    2016-06-15

    Highlights: • A reversed fabrication of low density foam columns coated with gold films was proposed. • The uniformity in thickness and purity of gold film are easy to be controlled. • A compact layer is prepared through an electrophoretic deposition method. • A low density (12 mg/cc) foam column coated with gold film is obtained. - Abstract: This work aims to fabricate low-density, porous, non-conductive, structural poly(divinylbenzene/styrene) foam columns by high-internal-phase emulsion templating. We prepare these non-conductive foam columns coated with a thin gold layer by electrochemical deposition and the reversed preparation technique. As expected, the density of the foam obtained through this novel method was about 12 mg cm{sup −3}, and the thickness of the gold coating was about 3 μm. We performed field emission scanning electron microscopy to morphologically and microstructurally characterize the products and X-ray diffraction and energy dispersive spectroscopy to determine the composition of the gold coating.

  5. Experimental investigation of sanding propensity for the Andrew completion

    Energy Technology Data Exchange (ETDEWEB)

    Venkitaraman, A.; Li, H. [Schlumberger Perforating and Testing Center (United Kingdom); Leonard, A. J.; Bowden, P. R. [BP Exploration (United Kingdom)

    1998-12-31

    A series of laboratory experiments were performed on three reservoir core samples selected from two plot wells to confirm the likelihood of sand production during the completion phase of the planned Andrew horizontal wells, and to perform risk analysis of formation failure at the time of underbalance perforation, and expected producing conditions. CT scans revealed no perforation failure, and the core samples did not show any propensity to produce sand during single-phase oil flow. Transient sand production was observed when water cut was introduced, but sand production declined as the percentage of water cut was increased. There was no evidence of sand production in the core samples during depletion testing either, and the wells were subsequently completed with perforated cemented liners without sand control. No sand problems have been encountered in two years of production, with some wells in water cut and declined reservoir pressure of 200 psi. 8 refs., 3 tabs., 5 figs.

  6. Evaluation of wettability of binders used in moulding sands

    Directory of Open Access Journals (Sweden)

    Hutera B.

    2007-01-01

    Full Text Available Binders used in moulding sand have the differential properties. One of the main parameters influencing on moulding sand properties is wettability of the sand grain by binding material. In the article some problems concerned with wettability evaluation have been presented and the importance of this parameter for quantity description of process occurring in system: binder- sand grain has been mentioned. The procedure of wetting angle measurement and operation of prototype apparatus for wettability investigation of different binders used in moulding sand have been described, as well as the results of wetting angle measurement for different binders at different conditions. The addition of little amount of proper diluent to binder results in the state of equilibrium reached almost immediately. Such addition can also reduce the value of equilibrium contact angle. The uniform distribution of binder on the surface of the sand grains and reducing of the required mixing time can be obtained. It has also a positive effect on the moulding sand strength.

  7. Properties of the Water Column and Bottom Derived from AVIRIS Data

    Science.gov (United States)

    Lee, Zhong-Ping; Carder, Kendall L.; Chen, F. Robert; Peacock, Thomas G.

    2001-01-01

    Using AVIRIS data as an example, we show in this study that the optical properties of the water column and bottom of a large, shallow area can be adequately retrieved using a model-driven optimization technique. The simultaneously derived properties include bottom depth, bottom albedo, and water absorption and backscattering coefficients, which in turn could be used to derive concentrations of chlorophyll, dissolved organic matter, and suspended sediments. The derived bottom depths were compared with a bathymetry chart and a boat survey and were found to agree very well. Also, the derived bottom-albedo image shows clear spatial patterns, with end members consistent with sand and seagrass. The image of absorption and backscattering coefficients indicates that the water is quite horizontally mixed. These results suggest that the model and approach used work very well for the retrieval of sub-surface properties of shallow-water environments even for rather turbid environments like Tampa Bay, Florida.

  8. Nuclear energy in the oils sands

    International Nuclear Information System (INIS)

    Arsenault, J.E.

    2014-01-01

    The major Canadian oil sands are located in Alberta and Saskatchewan, with most production from the strata along the Athabasca River in Alberta. The economically recoverable oil sands reserves are estimated to be 168 billion barrels which at a current production rate of 1.8 million barrels per day (2012), are projected to last a very long time. Canada has been blessed with vast energy resources which make it potentially energy-independent and able to provide significant exports but there are concerns that their development cannot be managed in a wholly acceptable manner. Comparable concerns have been applied to nuclear energy in the past and in recent times to the oil sands. The technologies associated with these energy sources have always been controversial because they are at the confluence of economics and politics where finding a balance between risk and reward is difficult. So it should be no surprise that when these technologies get linked together in certain proposals their prospect for success is doubly difficult. The possible use of nuclear energy for production of oil from the oil sands dates back to the late 1950s, when an experiment to mine the oil by detonating an underground nuclear device was proposed. It was predicted that the heat and pressure released from such a device would create a large cavern into which oil would flow, and from where it would be pumped to the surface. Almost at the same time, oil sands research using conventional sources of energy had culminated with the development of practical refining processes, essentially those still in use today. These methods require large amounts of heat energy in the form of hot water and steam. In this century nuclear energy was proposed as the source for the heat required by the oil sands production processes. To date neither of these nuclear proposals for oil sands projects have been successful, because the economic and political balance could not be struck. (author)

  9. The provenance of Taklamakan desert sand

    Science.gov (United States)

    Rittner, Martin; Vermeesch, Pieter; Carter, Andrew; Bird, Anna; Stevens, Thomas; Garzanti, Eduardo; Andò, Sergio; Vezzoli, Giovanni; Dutt, Ripul; Xu, Zhiwei; Lu, Huayu

    2016-03-01

    Sand migration in the vast Taklamakan desert within the Tarim Basin (Xinjiang Uyghur Autonomous region, PR China) is governed by two competing transport agents: wind and water, which work in diametrically opposed directions. Net aeolian transport is from northeast to south, while fluvial transport occurs from the south to the north and then west to east at the northern rim, due to a gradual northward slope of the underlying topography. We here present the first comprehensive provenance study of Taklamakan desert sand with the aim to characterise the interplay of these two transport mechanisms and their roles in the formation of the sand sea, and to consider the potential of the Tarim Basin as a contributing source to the Chinese Loess Plateau (CLP). Our dataset comprises 39 aeolian and fluvial samples, which were characterised by detrital-zircon U-Pb geochronology, heavy-mineral, and bulk-petrography analyses. Although the inter-sample differences of all three datasets are subtle, a multivariate statistical analysis using multidimensional scaling (MDS) clearly shows that Tarim desert sand is most similar in composition to rivers draining the Kunlun Shan (south) and the Pamirs (west), and is distinctly different from sediment sources in the Tian Shan (north). A small set of samples from the Junggar Basin (north of the Tian Shan) yields different detrital compositions and age spectra than anywhere in the Tarim Basin, indicating that aeolian sediment exchange between the two basins is minimal. Although river transport dominates delivery of sand into the Tarim Basin, wind remobilises and reworks the sediment in the central sand sea. Characteristic signatures of main rivers can be traced from entrance into the basin to the terminus of the Tarim River, and those crossing the desert from the south to north can seasonally bypass sediment through the sand sea. Smaller ephemeral rivers from the Kunlun Shan end in the desert and discharge their sediment there. Both river run

  10. Nuclear energy in the oils sands

    Energy Technology Data Exchange (ETDEWEB)

    Arsenault, J.E.

    2014-09-15

    The major Canadian oil sands are located in Alberta and Saskatchewan, with most production from the strata along the Athabasca River in Alberta. The economically recoverable oil sands reserves are estimated to be 168 billion barrels which at a current production rate of 1.8 million barrels per day (2012), are projected to last a very long time. Canada has been blessed with vast energy resources which make it potentially energy-independent and able to provide significant exports but there are concerns that their development cannot be managed in a wholly acceptable manner. Comparable concerns have been applied to nuclear energy in the past and in recent times to the oil sands. The technologies associated with these energy sources have always been controversial because they are at the confluence of economics and politics where finding a balance between risk and reward is difficult. So it should be no surprise that when these technologies get linked together in certain proposals their prospect for success is doubly difficult. The possible use of nuclear energy for production of oil from the oil sands dates back to the late 1950s, when an experiment to mine the oil by detonating an underground nuclear device was proposed. It was predicted that the heat and pressure released from such a device would create a large cavern into which oil would flow, and from where it would be pumped to the surface. Almost at the same time, oil sands research using conventional sources of energy had culminated with the development of practical refining processes, essentially those still in use today. These methods require large amounts of heat energy in the form of hot water and steam. In this century nuclear energy was proposed as the source for the heat required by the oil sands production processes. To date neither of these nuclear proposals for oil sands projects have been successful, because the economic and political balance could not be struck. (author)

  11. Sediment Source Fingerprinting of the Lake Urmia Sand Dunes.

    Science.gov (United States)

    Ahmady-Birgani, Hesam; Agahi, Edris; Ahmadi, Seyed Javad; Erfanian, Mahdi

    2018-01-09

    Aeolian sand dunes are continuously being discovered in inner dry lands and coastal areas, most of which have been formed over the Last Glacial Maximum. Presently, due to some natural and anthropogenic implications on earth, newly-born sand dunes are quickly emerging. Lake Urmia, the world's second largest permanent hypersaline lake, has started shrinking, vast lands comprising sand dunes over the western shore of the lake have appeared and one question has been playing on the minds of nearby dwellers: where are these sand dunes coming from, What there was not 15 years ago!! In the present study, the determination of the source of the Lake Urmia sand dunes in terms of the quantifying relative contribution of each upstream geomorphological/lithological unit has been performed using geochemical fingerprinting techniques. The findings demonstrate that the alluvial and the fluvial sediments of the western upstream catchment have been transported by water erosion and they accumulated in the lower reaches of the Kahriz River. Wind erosion, as a secondary agent, have carried the aeolian sand-sized sediments to the sand dune area. Hence, the Lake Urmia sand dunes have been originating from simultaneous and joint actions of alluvial, fluvial and aeolian processes.

  12. Properties of the water column and bottom derived from Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data

    Science.gov (United States)

    Lee, Zhongping; Carder, Kendall L.; Chen, Robert F.; Peacock, Thomas G.

    2001-06-01

    Using Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data as an example, we show in this study that the properties of the water column and bottom of a large, shallow area can be adequately retrieved using a model-driven optimization technique. The simultaneously derived properties include bottom depth, bottom albedo, and water absorption and backscattering coefficients, which in turn could be used to derive concentrations of chlorophyll, dissolved organic matter, and suspended sediments in the water column. The derived bottom depths were compared with a bathymetry chart and a boat survey and were found to agree very well. Also, the derived bottom albedo image shows clear spatial patterns, with end-members consistent with sand and seagrass. The image of absorption and backscattering coefficients indicates that the water is quite horizontally mixed. Without bottom corrections, chlorophyll a retrievals were ˜50 mg m-3, while the retrievals after bottom corrections were tenfold less, approximating real values. These results suggest that the model and approach used work very well for the retrieval of subsurface properties of shallow-water environments even for rather turbid environments like Tampa Bay, Florida.

  13. Changes in active eolian sand at northern Coachella Valley, California

    Science.gov (United States)

    Katra, Itzhak; Scheidt, Stephen; Lancaster, Nicholas

    2009-04-01

    Climate variability and rapid urbanization have influenced the sand environments in the northern Coachella Valley throughout the late 20th century. This paper addresses changes in the spatial relationships among different sand deposits at northern Coachella Valley between two recent time periods by using satellite data acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The approach employed here, involving multispectral thermal infrared (TIR) data and spectral mixture analysis, has shown that the major sand deposits can be spatially modeled at northern Coachella Valley. The "coarse-grained (quartz-rich) sand" deposit is associated with active eolian sand, and the "mixed sandy soil" and "fine-grained (quartz-rich) sand" deposits are associated with inactive eolian sand. The fractional abundance images showed a significant decrease between 2000 and 2006 in the percentage of active sand in the major depositional area for fluvial sediment, the Whitewater River, but also in two downwind areas: the Whitewater and Willow Hole Reserves. The pattern of the active sand appears to be related to variations in annual precipitation (wet and dry years) and river discharge in the northern Coachella Valley. We suggest here that recent human modifications to the major watercourses that supply sand affect the capability of fluvial deposition areas to restore sediments over time and consequently the responses of the sand transport system to climate change, becoming more sensitive to dry years where areas of active sand may shrink, degrade, and/or stabilize faster. The approach utilized in this study can be advantageous for future monitoring of sand in the northern Coachella Valley for management of these and similar environments.

  14. Namibia : triaxial test on sand

    DEFF Research Database (Denmark)

    Steenfelt, Jørgen S.; Jacobsen, Kim P.

    In connection with a harbour project the friction angle of a fine sand is required. On Friday 13 March 1998 the Danish Geotechnical Institute (DGI) delivered app. 2.5 kg sand for testing at the Geotechnical Engineering Laboratory, Aalborg University. The present Data Report summarises the results...... of two CID, isotropically consolidated, drained triaxial tests carried out according to the instructions in DG1 letter dated 13 March 1998....

  15. Pattern formation - Instabilities in sand ripples

    DEFF Research Database (Denmark)

    Hansen, J. L.; v. Hecke, M.; Haaning, A.

    2001-01-01

    Sand ripples are seen below shallow wavy water and are formed whenever water oscillates over a bed of sand. Here we analyse the instabilities that can upset this perfect patterning when the ripples are subjected to large changes in driving amplitude or frequency, causing them to deform both...

  16. Southeast Florida Sediment Assessment and Needs Determination (SAND) Study

    Science.gov (United States)

    2014-09-01

    sand with some shell beds, sandstone , and limestone *Miami Limestone 0 to 80 ft Oolitic limestone, quartz sand, and sandstone Anastasia 0 to 100 ft...Sand, shell beds, marl, calcareous sandstone (coquina/calcarenite) Fort Thompson 0 to 80 ft Silty limestone, silty sand, clayey marl, shell marl...highly- to moderately- weathered quartzose sandstone , and highly-weathered (saprolitic) to moderately-weathered hard limestone. North-south and

  17. Modelling the behavior of an oil saturated sand

    International Nuclear Information System (INIS)

    Evgin, E.; Altaee, A.; Lord, S.; Konuk, I.

    1990-01-01

    The experiments carried out in an earlier study show the oil contamination affects the strength and deformation characteristics of a crushed quartz sand. In the present study, a mathematical soil model is used to simulate the mechanical behavior of the same sand. The model parameters are determined for both clean and oil contaminated soil. Simulations are made for the stress-strain behavior of the soil in drained and undrained conventional traixial compression tests. In order to illustrate the effect of changes in the soil properties on the behavior of an engineering structure, a finite element analysis is carried out. In this paper comparative results are presented to show the differences in the behavior of a foundation resting on a clean sand, on an oil contaminated sand, and on a sand contaminated locally

  18. Oblique second-order sand transport pathways on an intertidal sand flat in a natural tidal inlet system

    DEFF Research Database (Denmark)

    Ernstsen, Verner Brandbyge; Lefebvre, Alice; Kroon, Aart

    2013-01-01

    tide, sand is transported along ESE-oriented pathways across the intertidal flat towards the inner tidal basin. During the late stages of ebb tide, sand is transported in drainage channels (WSWoriented) from the intertidal flat towards the inlet channel. During storm events with winds from SW, wave...

  19. Oil sands supply outlook

    International Nuclear Information System (INIS)

    Dunbar, R.

    2004-01-01

    In March 2004, The Canadian Energy Research Institute released a report on the expected future supply from Alberta's oil sands. The report indicates that the future for the already well-established oil sands industry is promising, particularly given the outlook for oil prices. The challenges facing the industry include higher industry supply costs and the need for innovative commercial and technological solutions to address the risks of irregularities and changes in crude oil prices. In 2003, the industry produced 874 thousand barrels per day of synthetic crude oil and unprocessed crude bitumen. This represents 35 per cent of Canada's total oil production. Current production capacity has increased to 1.0 million barrels per day (mbpd) due to new projects. This number may increase to 3.5 mbpd by 2017. Some new projects may be deferred due to the higher raw bitumen and synthetic crude oil supply costs. This presentation provided supply costs for a range of oil sands recovery technologies and production projections under various business scenarios. tabs., figs

  20. Gasification of oil sand coke: review

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E. [IMAF Group, Ottawa, ON (Canada)

    1998-08-01

    The production of synthetic crude from the tar sands in Western Canada has been steadily increasing. Most of the delayed coke produced by Suncor is combusted on site, whereas all fluid coke produced by Syncrude is stockpiled.The database on the chemical and physical properties of the oil sand coke, including the composition and fusion properties of the mineral matter, has been established. The reactivity of the coke was determined by oxygen chemisorption, fixed bed and fluid bed bench scale gasification and pilot plant gasification. The reactivity of the oil sand coke for gasification is rather low and comparable to high rank coals, such as anthracite. Slurrability tests revealed that a solid concentration in water, approaching 70 wt%, can be achieved. Gasification is the front runner among clean technologies for the conversion of carbonaceous solids to useful products. Several commercial gasifiers are available to cover the wide range of severity. Because of the low reactivity of oil sands coke, high severity conditions are required to achieve high gasification conversion. Such conditions can be attained in entrained bed gasifiers. Gasifiers employing both dry and slurry feeding systems are suitable. A high efficiency, low SO{sub x} and NO{sub x} emissions, as well as a low solid waste production are among the key advantages of the gasification technology compared with thecompeting technologies. Commercial gasification of oil sands coke is delayed because of the availability of natural gas on the site of the upgrading plants. Potential for the transportation of the oil sand coke to USA for electricity generation using the integrated gasification combined-cycle (IGCC) technology was evaluated. 27 refs., 17 figs., 9 tabs.

  1. Reuse of waste cutting sand at Lawrence Livermore National Laboratory

    International Nuclear Information System (INIS)

    Mathews, S.; Wilson, K.

    1998-01-01

    Lawrence Livermore National Laboratory (LLNL) examined the waste stream from a water jet cutting operation, to evaluate the possible reuse of waste garnet sand. The sand is a cutting agent used to shape a variety of materials, including metals. Nearly 70,000 pounds of waste sand is generated annually by the cutting operation. The Environmental Protection Department evaluated two potential reuses for the spent garnet sand: backfill in utility trenches; and as a concrete constituent. In both applications, garnet waste would replace the sand formerly purchased by LLNL for these purposes. Findings supported the reuse of waste garnet sand in concrete, but disqualified its proposed application as trench backfill. Waste sand stabilized in a concrete matrix appeared to present no metals-leaching hazard; however, unconsolidated sand in trenches could potentially leach metals in concentrations high enough to threaten ground water quality. A technical report submitted to the San Francisco Bay Regional Water Quality Control Board was reviewed and accepted by that body. Reuse of waste garnet cutting sand as a constituent in concrete poured to form walkways and patios at LLNL was approved

  2. Augmenting Sand Simulation Environments through Subdivision and Particle Refinement

    Science.gov (United States)

    Clothier, M.; Bailey, M.

    2012-12-01

    Recent advances in computer graphics and parallel processing hardware have provided disciplines with new methods to evaluate and visualize data. These advances have proven useful for earth and planetary scientists as many researchers are using this hardware to process large amounts of data for analysis. As such, this has provided opportunities for collaboration between computer graphics and the earth sciences. Through collaboration with the Oregon Space Grant and IGERT Ecosystem Informatics programs, we are investigating techniques for simulating the behavior of sand. We are also collaborating with the Jet Propulsion Laboratory's (JPL) DARTS Lab to exchange ideas and gain feedback on our research. The DARTS Lab specializes in simulation of planetary vehicles, such as the Mars rovers. Their simulations utilize a virtual "sand box" to test how a planetary vehicle responds to different environments. Our research builds upon this idea to create a sand simulation framework so that planetary environments, such as the harsh, sandy regions on Mars, are more fully realized. More specifically, we are focusing our research on the interaction between a planetary vehicle, such as a rover, and the sand beneath it, providing further insight into its performance. Unfortunately, this can be a computationally complex problem, especially if trying to represent the enormous quantities of sand particles interacting with each other. However, through the use of high-performance computing, we have developed a technique to subdivide areas of actively participating sand regions across a large landscape. Similar to a Level of Detail (LOD) technique, we only subdivide regions of a landscape where sand particles are actively participating with another object. While the sand is within this subdivision window and moves closer to the surface of the interacting object, the sand region subdivides into smaller regions until individual sand particles are left at the surface. As an example, let's say

  3. Mode conversion and its utilization of degenerating surface wave modes on a plasma column

    International Nuclear Information System (INIS)

    Nonaka, S.; Akao, Y.

    1983-01-01

    Both mode conversion at degenerating points of dispersion relations for surface wave modes on a discharge plasma column and the methods for their detection and utilization are presented. Mode conversions at three degenerating points become observable by using a surface wave resonator when an azimuthal inhomogeneity of plasma is produced by a static magnetic field of about 1 G applied perpendicular to the column axis. Two of the three detected degenerating points can be utilized for an easy and exact determination of the electron density and its distribution in the discharge tube

  4. Controlled crosslinking of trimethylolpropane trimethacrylate for preparation of organic monolithic columns for capillary liquid chromatography.

    Science.gov (United States)

    Gama, Mariana R; Aggarwal, Pankaj; Lee, Milton L; Bottoli, Carla B G

    2017-11-01

    Organic monolithic columns based on single crosslinking of trimethylolpropane trimethacrylate (TRIM) monomer were prepared in a single step by living/controlled free-radical polymerization. Full optimization of the preparation, such as using different percentages of TRIM and different amounts of radical promoter as well as various porogen solvents were explored. The resulting monolithic columns were characterized by scanning electronic microscopy and nitrogen sorption for structure morphology studies and surface area measurements, respectively. Using capillary liquid chromatography, 150 μm i.d. columns were applied to separate a mixture of small hydrophobic molecules. The results indicated that column performance is highly sensitive to the type and the amount of porogen solvents used in the polymerization mixture composition. Good resolution factors and methylene selectivity were obtained, indicating the promising potential of this material for capillary liquid chromatography separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Understanding Colombian Amazonian white sand forests

    NARCIS (Netherlands)

    Peñuela-Mora, M.C.

    2014-01-01

    Although progress has been made in studies on white sand forests in the Amazon, there is still a considerable gap in our knowledge of the unique species composition of white sand forests and their structure and dynamics, especially in Western Amazon. This thesis aims to fill this gap by addressing

  6. Nickel removal from nickel plating waste water using a biologically active moving-bed sand filter.

    Science.gov (United States)

    Pümpel, Thomas; Macaskie, Lynne E; Finlay, John A; Diels, Ludo; Tsezos, Marios

    2003-12-01

    Efficient removal of dissolved nickel was observed in a biologically active moving-bed 'MERESAFIN' sand filter treating rinsing water from an electroless nickel plating plant. Although nickel is fully soluble in this waste water, its passage through the sand filter promoted rapid removal of approximately 1 mg Ni/l. The speciation of Ni in the waste water was modelled; the most probable precipitates forming under the conditions in the filter were predicted using PHREEQC. Analyses of the Ni-containing biosludge using chemical, electron microscopical and X-ray spectroscopic techniques confirmed crystallisation of nickel phosphate as arupite (Ni3(PO4)2 x 8H2O), together with hydroxyapatite within the bacterial biofilm on the filter sand grains. Biosorption contributed less than 1% of the overall sequestered nickel. Metabolising bacteria are essential for the process; the definitive role of specific components of the mixed population is undefined but the increase in pH promoted by metabolic activity of some microbial components is likely to promote nickel desolubilisation by others.

  7. Development of spent salt treatment technology by zeolite column system. Performance evaluation of zeolite column

    International Nuclear Information System (INIS)

    Miura, Hidenori; Uozumi, Koichi

    2009-01-01

    At electrorefining process, fission products(FPs) accumulate in molten salt. To avoid influence on heating control by decay heat and enlargement of FP amount in the recovered fuel, FP elements must be removed from the spent salt of the electrorefining process. For the removal of the FPs from the spent salt, we are investigating the availability of zeolite column system. For obtaining the basic data of the column system, such as flow property and ion-exchange performance while high temperature molten salt is passing through the column, and experimental apparatus equipped with fraction collector was developed. By using this apparatus, following results were obtained. 1) We cleared up the flow parameter of column system with zeolite powder, such as flow rate control by argon pressure. 2) Zeolite 4A in the column can absorb cesium that is one of the FP elements in molten salt. From these results, we got perspective on availability of the zeolite column system. (author)

  8. Trajectories of saltating sand particles behind a porous fence

    Science.gov (United States)

    Zhang, Ning; Lee, Sang Joon; Chen, Ting-Guo

    2015-01-01

    Trajectories of aeolian sand particles behind a porous wind fence embedded in a simulated atmospheric boundary layer were visualized experimentally, to investigate the shelter effect of the fence on sand saltation. Two sand samples, one collected from a beach (d = 250 μm) and the other from a desert (d = 100 μm), were tested in comparison with the previous studies of a 'no-fence' case. A wind fence (ε = 38.5%) was installed on a flat sand bed filled with each sand sample. A high-speed photography technique and the particle tracking velocimetry (PTV) method were employed to reconstruct the trajectories of particles saltating behind the fence. The collision processes of these sand particles were analyzed, momentum and kinetic energy transfer between saltating particles and ground surface were also investigated. In the wake region, probability density distributions of the impact velocities agree well with the pattern of no-fence case, and can be explained by a log-normal law. The horizontal component of impact velocity for the beach sand is decreased by about 54%, and about 76% for the desert sand. Vertical restitution coefficients of bouncing particles are smaller than 1.0 due to the presence of the wind fence. The saltating particles lose a large proportion of their energy during the collision process. These results illustrate that the porous wind fence effectively abates the further evolution of saltating sand particles.

  9. Assessment of contamination by percolation of septic tank effluent through natural and amended soils.

    Science.gov (United States)

    Cheung, K C; Venkitachalam, T H

    2004-01-01

    Fly ash has been found to be a potential material for the treatment of municipal and industrial wastewater, and may be useful in the treatment of septic tank effluent. Laboratory columns (30 cm) were used to determine the sorption capacity and hydraulic properties of lagoon fly ash, loamy sand, sand, and sand amended by lagoon fly ash (30 and 60%) and red mud gypsum (20%). The removal of chemical oxygen demand (COD) was high in all column effluents (71-93%). Extent of nitrification was high in Spearwood sand, Merribrook loamy sand and 20% red mud gypsum amended Spearwood sand. However, actual removal of nitrogen (N) was high in columns containing lagoon fly ash. Unamended Spearwood sand possessed only minimal capacity for P sorption. Merribrook loamy sand and red mud gypsum amended sand affected complete P removal throughout the study period of 12 weeks. Significant P leakage occurred from lagoon fly ash amended sand columns following 6-10 weeks of operation. Neither lagoon fly ash nor red mud gypsum caused any studied heavy metal contamination including manganese (Mn), lead (Pb), zinc (Zn), cadmium (Cd) and chromium (Cr) of effluent. It can be concluded that Merribrook loamy sand is better natural soil than Spearwood sand as a filter medium. The addition of lagoon fly ash enhanced the removal of P in Spearwood sand but the efficiency was lower than with red mud gypsum amendment.

  10. Biodegradable materials as binders for IVth generation moulding sands

    OpenAIRE

    K. Major-Gabry

    2015-01-01

    This paper focuses on the possibility of using the biodegradable materials as binders (or parts of binders?compositions) for foundry moulding and core sands. Results showed that there is a great possibility of using available biodegradable materials as foundry moulding sand binders. Using biodegradable materials as partial content of new binders, or additives to moulding sands may not only decrease the toxicity and increase reclamation ability of tested moulding sands, but also accelerate the...

  11. Retention of silica nanoparticles on calcium carbonate sands immersed in electrolyte solutions

    KAUST Repository

    Li, Yan Vivian

    2014-12-01

    © 2014 Elsevier Inc. Understanding nanoparticle-surface adhesion is necessary to develop inert tracers for subsurface applications. Here we show that nanoparticles with neutral surface charge may make the best subsurface tracers, and that it may be possible to used SiO2 nanoparticle retention to measure the fraction of solid surface that has positive charge. We show that silica nanoparticles dispersed in NaCl electrolyte solutions are increasingly retained in calcium carbonate (calcite) sand-packed columns as the solution ionic strength increases, but are not retained if they are injected in pure water or Na2SO4 electrolyte solutions. The particles retained in the NaCl experiments are released when the column is flushed with pure water or Na2SO4 solution. AFM measurements on calcite immersed in NaCl solutions show the initial repulsion of a silica colloidal probe as the surface is approached is reduced as the solution ionic strength increases, and that at high ionic strengths it disappears entirely and only attraction remains. These AFM measurements and their interpretation with Derjaguin-Landau-Verwey-Overbeek (DLVO) theory shows the calcite surface charge is always negative for Na2SO4 solutions, but changes from negative to positive in a patchy fashion as the ionic strength of the NaCl solution increases. Since mixed-charge (patchy) surfaces may be common in the subsurface, nanoparticles with near-zero charge may make the best tracers.

  12. The Canadian oil sands--a sticky future

    Energy Technology Data Exchange (ETDEWEB)

    Cowtan, S A

    1977-01-01

    The oil sands have been known for 200 yr but only over the last decade have they been recognized as a potential major energy source for Canada. The study looks at the present GCOS plant, and briefly discusses Canada's future energy requirements and how she might fill those requirements from conventional and nonconventional sources, such as the Frontier areas, oil sands mining, oil sands in situ, and heavy oil. The economics and the future of these sources and the environment necessary for their development are analyzed.

  13. Thermoluminescent dosimetric properties of Descalvado sand

    International Nuclear Information System (INIS)

    Teixeira, M.I.; Caldas, L.V.E.

    2006-01-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ( 60 Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  14. Thermoluminescent dosimetric properties of Descalvado sand

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, M.I.; Caldas, L.V.E

    2006-07-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ({sup 60} Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  15. A Improved Seabed Surface Sand Sampling Device

    Science.gov (United States)

    Luo, X.

    2017-12-01

    In marine geology research it is necessary to obtain a suf fcient quantity of seabed surface samples, while also en- suring that the samples are in their original state. Currently,there are a number of seabed surface sampling devices available, but we fnd it is very diffcult to obtain sand samples using these devices, particularly when dealing with fne sand. Machine-controlled seabed surface sampling devices are also available, but generally unable to dive into deeper regions of water. To obtain larger quantities of seabed surface sand samples in their original states, many researchers have tried to improve upon sampling devices,but these efforts have generally produced ambiguous results, in our opinion.To resolve this issue, we have designed an improved andhighly effective seabed surface sand sampling device that incorporates the strengths of a variety of sampling devices. It is capable of diving into deepwater to obtain fne sand samples and is also suited for use in streams, rivers, lakes and seas with varying levels of depth (up to 100 m). This device can be used for geological mapping, underwater prospecting, geological engineering and ecological, environmental studies in both marine and terrestrial waters.

  16. Mitigating in situ oil sands carbon costs

    Energy Technology Data Exchange (ETDEWEB)

    Theriault, D.J.; Peterson, J. [Laricina Energy Ltd., Calgary, AB (Canada); Heinrichs, H. [Canadian Chemical Technology Inc., Calgary, AB (Canada)

    2008-10-15

    Carbon capture and sequestration is a complex problem with a variety of dimensions that need to be considered. The political, social, and regulatory pressures are forcing carbon costs on the oil sands industry in an effort to reduce the carbon footprint of oil sands operations. This paper reviewed the political, social, and regulatory pressures and obligations for the in-situ oil sands industry. It presented the views and insights of Laricina Energy on the carbon challenge. It also described the initiatives that Laricina Energy is taking to manage these imperatives and outlined the challenges the industry is facing. The purpose of the paper was to encourage dialogue and collaboration by the oil sands industry. The paper also described the dimensions of the carbon problem and how the industry can contribute to a solution. Last, the paper reviewed the parameters of carbon dioxide or greenhouse gas containment and storage issues. It was concluded that the regulatory and policy requirements need to be clarified so that industry understands the new business landscape as well as the requirements that influence the economics of in-situ oil sands development. 7 refs., 7 figs.

  17. Performance evaluation of a rectifier column using gamma column scanning

    Directory of Open Access Journals (Sweden)

    Aquino Denis D.

    2017-12-01

    Full Text Available Rectifier columns are considered to be a critical component in petroleum refineries and petrochemical processing installations as they are able to affect the overall performance of these facilities. It is deemed necessary to monitor the operational conditions of such vessels to optimize processes and prevent anomalies which could pose undesired consequences on product quality that might lead to huge financial losses. A rectifier column was subjected to gamma scanning using a 10-mCi Co-60 source and a 2-inch-long detector in tandem. Several scans were performed to gather information on the operating conditions of the column under different sets of operating parameters. The scan profiles revealed unexpected decreases in the radiation intensity at vapour levels between trays 2 and 3, and between trays 4 and 5. Flooding also occurred during several scans which could be attributed to parametric settings.

  18. Dispersion characteristics of electromagnetic waves in dipolar (m=±1) modes travelling along a magnetized plasma column

    International Nuclear Information System (INIS)

    Benova, E.; Ghanashev, I.; Zhelyazkov, I.

    1992-01-01

    The modelling of isotropic plasma columns sustained by travelling electromagnetic waves in the dipolar mode (angular dependence exp imφ, m=±1) shows that the m=±1 modes have identical dispersion characteristics. In the presence of an external static magnetic field, however, the modes behave rather differently. This observation arose in studying the axial structures of magnetized plasma columns surrounded by vacuum and produced by travelling electromagnetic waves in the dipolar modes. We examine the propagation of electromagnetic waves along a homogeneous cold plasma column of radius R and electron number density n immersed in an axial constant magnetic field. (author) 3 refs., 3 figs

  19. Single column and two-column H-D-T distillation experiments at TSTA

    International Nuclear Information System (INIS)

    Yamanishi, T.; Yoshida, H.; Hirata, S.; Naito, T.; Naruse, Y.; Sherman, R.H.; Bartlit, J.R.; Anderson, J.L.

    1988-01-01

    Cryogenic distillation experiments were peformed at TSTA with H-D-T system by using a single column and a two-column cascade. In the single column experiment, fundamental engineering data such as the liquid holdup and the HETP were measured under a variety of operational condtions. The liquid holdup in the packed section was about 10 /approximately/ 15% of its superficial volume. The HETP values were from 4 to 6 cm, and increased slightly with the vapor velocity. The reflux ratio had no effect on the HETP. For the wo-colunn experiemnt, dynamic behavior of the cascade was observed. 8 refs., 7 figs., 2 tabs

  20. Preparation of Affinity Column Based on Zr{sup 4+} Ion for Phosphoproteins Isolation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seon Mi; Bae, In Ae; Park, Jung Hyen; Kim, Tae Dong; Choi, Seong Ho [Hannam University, Daejeon (Korea, Republic of)

    2009-06-15

    This paper has described about preparation of Zr{sup 4+} affinity column based on the poly(styreneco- glycidyl methacrylate) prepared by emulsion polymerization of styrene and glycidyl methacrylate in order to isolate phosphopeptide. The Zr{sup 4+} ions were introduced after the phophonation of an epoxy group on polymeric microspheres. The successful preparation of Zr{sup 4+}-immobilized polymeric microsphere stationary phase was confirmed through Fourier transform infrared spectra, optical microscopy, scanning electron microscopy, X-ray photoelectron spectra and inductively coupled plasma-atomic emission spectrometer. The separation efficiency for Zr{sup 4+} affinity column prepared by slurry packing was tested to phosphonated casein and dephosphonated casein. The resolution time (min) of the phosphonated casein was higher than that of dephosphated casein for Zr{sup 4+} affinity polymeric microsphere by liquid chromatography. This Zr{sup 4+} affinity column can be used for isolation of phosphonated casein from casein using liquid chromatography.

  1. Effectiveness of SCADA Systems in Control of Green Sands Properties

    Directory of Open Access Journals (Sweden)

    Ignaszak Z.

    2016-03-01

    Full Text Available The paper undertakes an important topic of evaluation of effectiveness of SCADA (Supervisory Control and Data Acquisition systems, used for monitoring and control of selected processing parameters of classic green sands used in foundry. Main focus was put on process studies of properties of so-called 1st generation molding sands in the respect of their preparation process. Possible methods of control of this processing are presented, with consideration of application of fresh raw materials, return sand (regenerate and water. The studies conducted in one of European foundries were aimed at pointing out how much application of new, automated plant of sand processing incorporating the SCADA systems allows stabilizing results of measurement of selected sand parameters after its mixing. The studies concerned two comparative periods of time, before an implementation of the automated devices for green sands processing (ASMS - Automatic Sand Measurement System and MCM – Main Control Module and after the implementation. Results of measurement of selected sand properties after implementation of the ASMS were also evaluated and compared with testing studies conducted periodically in laboratory.

  2. Non-Fickian dispersive transport of strontium in laboratory-scale columns: Modelling and evaluation

    Science.gov (United States)

    Liu, Dongxu; Jivkov, Andrey P.; Wang, Lichun; Si, Gaohua; Yu, Jing

    2017-06-01

    In the context of environmental remediation of contaminated sites and safety assessment of nuclear waste disposal in the near-surface zone, we investigate the leaching and non-Fickian dispersive migration with sorption of strontium (mocking strontium-90) through columns packed with sand and clay. Analysis is based on breakthrough curves (BTCs) from column experiments, which simulated rainfall infiltration and source term release scenario, rather than applying constant tracer solution at the inlet as commonly used. BTCs are re-evaluated and transport parameters are estimated by inverse modelling using two approaches: (1) equilibrium advection-dispersion equation (ADE); and (2) continuous time random walk (CTRW). Firstly, based on a method for calculating leach concentration, the inlet condition with an exponential decay input is identified. Secondly, the results show that approximately 39%-58% of Br- and 16%-49% of Sr2+ are eluted from the columns at the end of the breakthrough experiments. This suggests that trapping mechanisms, including diffusion into immobile zones and attachment of tracer on mineral surfaces, are more pronounced for Sr2+ than for Br-. Thirdly, we demonstrate robustness of CTRW-based truncated power-law (TPL) model in capturing non-Fickian reactive transport with 0 2. The non-Fickian dispersion observed experimentally is explained by variations of local flow field from preferential flow paths due to physical heterogeneities. Particularly, the additional sorption process of strontium on clay minerals contributes to the delay of the peak concentration and the tailing features, which leads to an enhanced non-Fickian transport for strontium. Finally, the ADE and CTRW approaches to environmental modelling are evaluated. It is shown that CTRW with a sorption term can describe non-Fickian dispersive transport of strontium at laboratory scale by identifying appropriate parameters, while the traditional ADE with a retardation factor fails to reproduce

  3. A hand-held row-column addressed CMUT probe with integrated electronics for volumetric imaging

    DEFF Research Database (Denmark)

    Engholm, Mathias; Christiansen, Thomas Lehrmann; Beers, Christopher

    2015-01-01

    A 3 MHz, λ / 2-pitch 62+62 channel row-column addressed 2-D CMUT array designed to be mounted in a probe handle and connected to a commercial BK Medical scanner for real-time volumetric imaging is presented. It is mounted and wire-bonded on a flexible PCB, which is connected to two rigid PCBs...

  4. ON THE ORIGIN OF THE HIGH COLUMN DENSITY TURNOVER IN THE H I COLUMN DENSITY DISTRIBUTION

    International Nuclear Information System (INIS)

    Erkal, Denis; Gnedin, Nickolay Y.; Kravtsov, Andrey V.

    2012-01-01

    We study the high column density regime of the H I column density distribution function and argue that there are two distinct features: a turnover at N H I ≈ 10 21 cm –2 , which is present at both z = 0 and z ≈ 3, and a lack of systems above N H I ≈ 10 22 cm –2 at z = 0. Using observations of the column density distribution, we argue that the H I-H 2 transition does not cause the turnover at N H I ≈ 10 21 cm –2 but can plausibly explain the turnover at N H I ∼> 10 22 cm –2 . We compute the H I column density distribution of individual galaxies in the THINGS sample and show that the turnover column density depends only weakly on metallicity. Furthermore, we show that the column density distribution of galaxies, corrected for inclination, is insensitive to the resolution of the H I map or to averaging in radial shells. Our results indicate that the similarity of H I column density distributions at z = 3 and 0 is due to the similarity of the maximum H I surface densities of high-z and low-z disks, set presumably by universal processes that shape properties of the gaseous disks of galaxies. Using fully cosmological simulations, we explore other candidate physical mechanisms that could produce a turnover in the column density distribution. We show that while turbulence within giant molecular clouds cannot affect the damped Lyα column density distribution, stellar feedback can affect it significantly if the feedback is sufficiently effective in removing gas from the central 2-3 kpc of high-redshift galaxies. Finally, we argue that it is meaningful to compare column densities averaged over ∼ kpc scales with those estimated from quasar spectra that probe sub-pc scales due to the steep power spectrum of H I column density fluctuations observed in nearby galaxies.

  5. Effective Laboratory Method of Chromite Content Estimation in Reclaimed Sands

    Directory of Open Access Journals (Sweden)

    Ignaszak Z.

    2016-09-01

    Full Text Available The paper presents an original method of measuring the actual chromite content in the circulating moulding sand of foundry. This type of material is applied for production of moulds. This is the case of foundry which most frequently perform heavy casting in which for the construction of chemical hardening mould is used, both the quartz sand and chromite sand. After the dry reclamation of used moulding sand, both types of sands are mixed in various ratios resulting that in reclaimed sand silos, the layers of varying content of chromite in mixture are observed. For chromite recuperation from the circulating moulding sand there are applied the appropriate installations equipped with separate elements generating locally strong magnetic field. The knowledge of the current ratio of chromite and quartz sand allows to optimize the settings of installation and control of the separation efficiency. The arduous and time-consuming method of determining the content of chromite using bromoform liquid requires operational powers and precautions during using this toxic liquid. It was developed and tested the new, uncomplicated gravimetric laboratory method using powerful permanent magnets (neodymium. The method is used in the production conditions of casting for current inspection of chromite quantity in used sand in reclamation plant.

  6. Adiabatic packed column supercritical fluid chromatography using a dual-zone still-air column heater.

    Science.gov (United States)

    Helmueller, Shawn C; Poe, Donald P; Kaczmarski, Krzysztof

    2018-02-02

    An approach to conducting SFC separations under pseudo-adiabatic condition utilizing a dual-zone column heater is described. The heater allows for efficient separations at low pressures above the critical temperature by imposing a temperature profile along the column wall that closely matches that for isenthalpic expansion of the fluid inside the column. As a result, the efficiency loss associated with the formation of radial temperature gradients in this difficult region can be largely avoided in packed analytical scale columns. For elution of n-octadecylbenzene at 60 °C with 5% methanol modifier and a flow rate of 3 mL/min, a 250 × 4.6-mm column packed with 5-micron Kinetex C18 particles began to lose efficiency (8% decrease in the number of theoretical plates) at outlet pressures below 142 bar in a traditional forced air oven. The corresponding outlet pressure for onset of excess efficiency loss was decreased to 121 bar when the column was operated in a commercial HPLC column heater, and to 104 bar in the new dual-zone heater operated in adiabatic mode, with corresponding increases in the retention factor for n-octadecylbenzene from 2.9 to 6.8 and 14, respectively. This approach allows for increased retention and efficient separations of otherwise weakly retained analytes. Applications are described for rapid SFC separation of an alkylbenzene mixture using a pressure ramp, and isobaric separation of a cannabinoid mixture. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Big picture thinking in oil sands tailings disposal

    Energy Technology Data Exchange (ETDEWEB)

    Boswell, J. [Thurber Engineering Ltd., Calgary, AB (Canada)

    2010-07-01

    This PowerPoint presentation discussed methods of disposing oil sands tailings. Oil sands operators are currently challenged by a variety of legislative and environmental factors concerning the creation and disposal of oil sands tailings. The media has focused on the negative ecological impact of oil sands production, and technical issues are reducing the effect of some mitigation processes. Operators must learn to manage the interface between tailings production and removal, the environment, and public opinion. The successful management of oil sand tailings will include procedures designed to improve reclamation processes, understand environmental laws and regulations, and ensure that the cumulative impacts of tailings are mitigated. Geotechnical investigations, engineering designs and various auditing procedures can be used to develop tailings management plans. Environmental screening and impact assessments can be used to develop sustainable solutions. Public participation and environmental mediation is needed to integrate the public, environmental and technical tailings management strategies. Operators must ensure public accountability for all stakeholders. tabs., figs.

  8. Influence of pressure on the properties of chromatographic columns. II. The column hold-up volume.

    Science.gov (United States)

    Gritti, Fabrice; Martin, Michel; Guiochon, Georges

    2005-04-08

    The effect of the local pressure and of the average column pressure on the hold-up column volume was investigated between 1 and 400 bar, from a theoretical and an experimental point of view. Calculations based upon the elasticity of the solids involved (column wall and packing material) and the compressibility of the liquid phase show that the increase of the column hold-up volume with increasing pressure that is observed is correlated with (in order of decreasing importance): (1) the compressibility of the mobile phase (+1 to 5%); (2) in RPLC, the compressibility of the C18-bonded layer on the surface of the silica (+0.5 to 1%); and (3) the expansion of the column tube (columns packed with the pure Resolve silica (0% carbon), the derivatized Resolve-C18 (10% carbon) and the Symmetry-C18 (20% carbon) adsorbents, using water, methanol, or n-pentane as the mobile phase. These solvents have different compressibilities. However, 1% of the relative increase of the column hold-up volume that was observed when the pressure was raised is not accounted for by the compressibilities of either the solvent or the C18-bonded phase. It is due to the influence of the pressure on the retention behavior of thiourea, the compound used as tracer to measure the hold-up volume.

  9. Least tern and piping plover nesting at sand pits in Nebraska

    Science.gov (United States)

    Sidle, John G.; Kirsch, E.M.

    1993-01-01

    Endangered Least Terns (Sterna antillarum) and threatened Piping Plovers (Charadrius melodus) nest at commercial sand and gravel mining operations (sand pits) along the Platte River system in Nebraska. Sandbar habitat has been disappearing since the early 1900's along the Platte River system, but numbers of sand pits have increased. We hypothesized that birds would more fully utilize sand pits where suitable sandbar habitat was limited. We inventoried sand pits and censused terns and plovers on both habitats along the Loup River, part of the North Loup River, and most of the Platte River during 1988-1991. Using aircraft, we also quantified features of suitable sand pits present on the central Platte in 1988 and lower Platte in 1990, and related features to abundance and presence of birds. We found 225 sand pits of which 78 were suitable and 187 were unsuitable for nesting. Along the central Platte, where sandbar habitat is severely degraded, birds nested at 81% of the suitable sand pits (N = 32) at least once during 1988-1991, and most birds (61-94%) nested on sand pits. Along the lower Platte, where both sandbar and sand pit habitat are plentiful, birds nested at 60% of the suitable sand pits (N = 35) at least once during 1988-1991, and most birds (60-86%) nested on sandbars. Numbers of terns and plovers were more weakly correlated with features of sand pits on the central Platte than on the lower Platte. Least Terns and Piping Plovers seem to use more of the suitable sand pit habitat on the central Platte than on the lower Platte. Sand pits probably have influenced the birds' distribution by providing alternative nesting habitat along rivers where suitable sandbars are rare or absent.

  10. Characterization of sand lenses embedded in tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Klint, K.E.S.; Nilsson, B.

    2012-01-01

    Tills dominate large parts of the superficial sediments on the Northern hemisphere. These glacial diamictons are extremely heterogeneous and riddled with fractures and lenses of sand or gravel. The frequency and geometry of sand lenses within tills are strongly linked to glaciodynamic processes...

  11. Sand impaction of the small intestine in eight dogs.

    Science.gov (United States)

    Moles, A D; McGhite, A; Schaaf, O R; Read, R

    2010-01-01

    To describe signalment, clinical findings, imaging and treatment of intestinal sand impaction in the dog. Medical records of dogs with radiographic evidence of small intestinal sand impaction were reviewed. Sand impaction resulting in small intestinal obstruction was diagnosed in eight dogs. All dogs presented with signs of vomiting. Other clinical signs included anorexia, lethargy and abdominal pain. Radiographs confirmed the presence of radio-opaque material consistent with sand causing distension of the terminal small intestine in all dogs. Four dogs were treated surgically for their impaction and four dogs were managed medically. Seven of the eight dogs survived. Both medical and surgical management of intestinal sand impaction in the dog can be effective and both afford a good prognosis for recovery.

  12. Consolidation of the formation sand by chemical methods

    Directory of Open Access Journals (Sweden)

    Mariana Mihočová

    2006-10-01

    Full Text Available The sand control by consolidation involves the process of injecting chemicals into the naturally unconsolidated formation to provide an in situ grain-to-grain cementation. The sand consolidation chemicals are available for some 30 years. Several types of consolidating material were tried. Presently available systems utilize solidified plastics to provide the cementation. These systems include phenol resin, phenol-formaldehyde, epoxy, furan and phenolic-furfuryl.The sand consolidation with the steam injection is a novel technique. This process provides a highly alkaline liquid phase and temperatures to 300 °C to geochemically create cements by interacting with the dirty sand.While the formation consolidation has widely applied, our experience has proved a high level of success.

  13. Transparent, Ultrahigh-Gas-Barrier Films with a Brick-Mortar-Sand Structure.

    Science.gov (United States)

    Dou, Yibo; Pan, Ting; Xu, Simin; Yan, Hong; Han, Jingbin; Wei, Min; Evans, David G; Duan, Xue

    2015-08-10

    Transparent and flexible gas-barrier materials have shown broad applications in electronics, food, and pharmaceutical preservation. Herein, we report ultrahigh-gas-barrier films with a brick-mortar-sand structure fabricated by layer-by-layer (LBL) assembly of XAl-layered double hydroxide (LDH, X=Mg, Ni, Zn, Co) nanoplatelets and polyacrylic acid (PAA) followed by CO2 infilling, denoted as (XAl-LDH/PAA)n-CO2. The near-perfectly parallel orientation of the LDH "brick" creates a long diffusion length to hinder the transmission of gas molecules in the PAA "mortar". Most significantly, both the experimental studies and theoretical simulations reveal that the chemically adsorbed CO2 acts like "sand" to fill the free volume at the organic-inorganic interface, which further depresses the diffusion of permeating gas. The strategy presented here provides a new insight into the perception of barrier mechanism, and the (XAl-LDH/PAA)n-CO2 film is among the best gas barrier films ever reported. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Geotechnical properties of crude oil contaminated sand

    International Nuclear Information System (INIS)

    Puri, V.K.; Das, B.M.; Cook, E.E.; Shin, E.C.

    1994-01-01

    Contamination of soil due to an oil spill influences its subsequent engineering behavior. An investigation was conducted to study the effect of crude oil contamination on compaction characteristics, shear strength, one-dimensional compression, and coefficient of permeability. Water permeability was also determined by using commercial grade motor oils as contaminants. The test results indicate that the compaction characteristics are influenced by oil contamination. The angle of internal friction of sand (based on total stress condition) decreases due to presence of oil within the pore spaces in sand. One dimensional compression characteristics of sand are significantly influenced by oil contamination resulting in a decrease in the value of constrained modulus with increase in the degree of oil contamination compared to the case of dry sand. Water permeability was observed to be a function of the initial viscosity and the degree of saturation due to the contaminating oil

  15. Elevated concentrations of naturally occurring radionuclides in heavy mineral-rich beach sands of Langkawi Island, Malaysia.

    Science.gov (United States)

    Khandaker, Mayeen Uddin; Asaduzzaman, Khandoker; Sulaiman, Abdullah Fadil Bin; Bradley, D A; Isinkaye, Matthew Omoniyi

    2018-02-01

    Study is made of the radioactivity in the beach sands of Langkawi island, a well-known tourist destination. Investigation is made of the relative presence of the naturally occurring radionuclide 40 K and the natural-series indicator radionuclides 226 Ra and 232 Th, the gamma radiation exposure also being estimated. Sample quantities of black and white sand were collected for gamma ray spectrometry, yielding activity concentration in black sands of 226 Ra, 232 Th and 40 K from 451±9 to 2411±65Bqkg -1 (mean of 1478Bqkg -1 ); 232±4 to 1272±35Bqkg -1 (mean of 718Bqkg -1 ) and 61±6 to 136±7Bqkg -1 (mean of 103Bqkg -1 ) respectively. Conversely, in white sands the respective values for 226 Ra and 232 Th were appreciably lower, at 8.3±0.5 to 13.7±1.4Bqkg -1 (mean of 9.8Bqkg -1 ) and 4.5±0.7 to 9.4±1.0Bqkg -1 (mean of 5.9Bqkg -1 ); 40 K activities differed insubstantially from that in black sands, at 85±4 to 133±7Bqkg -1 with a mean of 102Bqkg -1 . The mean activity concentrations of 226 Ra and 232 Th in black sands are comparable with that of high background areas elsewhere in the world. The heavy minerals content gives rise to elevated 226 Ra and 232 Th activity concentrations in all of black sand samples. Evaluation of the various radiological risk parameters points to values which in some cases could be in excess of recommendations providing for safe living and working. Statistical analysis examines correlations between the origins of the radionuclides, also identifying and classifying the radiological parameters. Present results may help to form an interest in rare-earth resources for the electronics industry, power generation and the viability of nuclear fuels cycle resources. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Sanding dust from nanoparticle-containing paints: Physical characterisation

    International Nuclear Information System (INIS)

    Koponen, I K; Jensen, K A; Schneider, T

    2009-01-01

    Increasing use of nanoparticles in different industrial applications has raised a new potential health risk to the workers as well as to the consumers. This study investigates the particle size distributions of sanding dust released from paints produced with and without engineered nanoparticles. Dust emissions from sanding painted plates were found to consist of five size modes; three modes under 1 μm and two modes around 1 and 2 μm. We observed that the sander was the only source of particles smaller than 50 nm and they dominated the number concentration spectra. Mass and surface area spectra were dominated by the 1 and 2 μm modes. Addition of nanoparticles caused only minor changes in the geometric mean diameters of the particle modes generated during sanding of two paints doped with 17 nm TiO2 and 95 nm Carbon Black nanoparticles as compared to the size modes generated during sanding a conventional reference paint. However, the number concentrations in the different size modes varied considerably in between the two NP-doped paints and the reference paint. Therefore, from a physical point of view, there may be a difference in the exposure risk during sanding surfaces covered with nanoparticle-based paints as compared to sanding conventional paints.

  17. Admittance Scanning for Whole Column Detection.

    Science.gov (United States)

    Stamos, Brian N; Dasgupta, Purnendu K; Ohira, Shin-Ichi

    2017-07-05

    Whole column detection (WCD) is as old as chromatography itself. WCD requires an ability to interrogate column contents from the outside. Other than the obvious case of optical detection through a transparent column, admittance (often termed contactless conductance) measurements can also sense changes in the column contents (especially ionic content) from the outside without galvanic contact with the solution. We propose here electromechanically scanned admittance imaging and apply this to open tubular (OT) chromatography. The detector scans across the column; the length resolution depends on the scanning velocity and the data acquisition frequency, ultimately limited by the physical step resolution (40 μm in the present setup). Precision equal to this step resolution was observed for locating an interface between two immiscible liquids inside a 21 μm capillary. Mechanically, the maximum scanning speed was 100 mm/s, but at 1 kHz sampling rate and a time constant of 25 ms, the highest practical scan speed (no peak distortion) was 28 mm/s. At scanning speeds of 0, 4, and 28 mm/s, the S/N for 180 pL (zone length of 1.9 mm in a 11 μm i.d. column) of 500 μM KCl injected into water was 6450, 3850, and 1500, respectively. To facilitate constant and reproducible contact with the column regardless of minor variations in outer diameter, a double quadrupole electrode system was developed. Columns of significant length (>1 m) can be readily scanned. We demonstrate its applicability with both OT and commercial packed columns and explore uniformity of retention along a column, increasing S/N by stopped-flow repeat scans, etc. as unique applications.

  18. Cotransport of microorganisms and metallic colloids in quartz sand or iron oxide-coated sand under real site hydrogeological conditions

    Science.gov (United States)

    Yu, Tong; Wen, Yujuan; Yang, Xinyao; Yang, Yuesuo

    2017-04-01

    plays an important part in many soil and water processes. The column experiments were carried out using homogeneously charged (quartz sand) and heterogeneously charged (iron oxide-coated sand) porous media. References: Yang, X., Zhang, Y., Chen, F., & Yang, Y. (2015). Interplay of natural organic matter with flow rate and particle size on colloid transport: Experimentation, visualization, and modeling. Environmental science & technology, 49(22), 13385-13393. Yang, X., Yin, Z., Chen, F., Hu, J., & Yang, Y. (2015). Organic matter induced mobilization of polymer-coated silver nanoparticles from water-saturated sand. Science of the Total Environment, 529, 182-190. Wen, Y. J., Yang, Y. S., Ren, H. J., Du, X. Q., Yang, X. Y., Zhang, L. Y., & Wang, X. S. (2015). Chemical-biological hybrid reactive zones and their impact on biodiversity of remediation of the nitrobenzene and aniline contaminated groundwater. Chemical Engineering Journal, 280, 233-240.

  19. [Preliminary Study of Lonicera hypoglauca on Germination Conditions of Sand Culture Seeds and Sterilization Method of Sand Culture Seedling Sterilization].

    Science.gov (United States)

    Tan, Mu-xiu; Zeng, Wen-wen; Wei, Peng-xiao; Mo, Qiao-cheng; Pu, Zu-ning; Cen, Xiu-fen; Shi, Feng-hua

    2015-05-01

    To explore the germination conditions of Lonicera hypoglauca sand culture seeds and the effects of sand culture seedlings sterilization. 0.1% HgCl2 with different sterilization time, different illumination time and temperature culture condition were adopted to study the germination conditions of sand culture seeds. Different sterilization treatments and different hardening-seedling days were used to test the sterilization effect of sand culture seedlings. The sterilization effect of the combination of 75% ethanol 30 s + 0.1% HgCl2 5 min on Lonicera hypoglauca seeds was the optimum,with the average pollution rate of 15.56%, and the average germination rate reached 51.11%. The combination of varied temperature-room temperature under light for 12 h/d was the best, with the average germination rate peaked at 75.49%, and the average germination potential reached 68.36%. The treatment of detergent liquor scrub-tap water wash on the part above the hypocotyl, which was sand cultured under the opening condition and had no root, showed the best sterilization effect, with the average pollution rate was zero, and the average survival rate peaked at 100.00%. The sterilization effect of sand culture seedlings, which was disinfected after cleaning by detergent liquor scrub-tap water wash after hardening-seeding for 30 days, was the best, with the average pollution rate of 50.00%, and the average survival rate of 100.00%. The best sterilization effect is the combination of 75% ethanol 30 s + 0.1% HgCl2 5 min; Lighting for 12 h/d of varied temperature-room temperature is regarded as the optimum culture condition. The treatment of detergent liquor scrub-tap water wash treatment on the part above the hypocotyl,which is sand cultured under the opening condition and had no root, shows the best sterilization effect. For the sand culture seedlings, before inoculated in subculture medium, should be hardening-seedling for some days and sterilized after detergent liquor scrub-tap water wash.

  20. The effects of carbide column to swelling potential and Atterberg limit on expansive soil with column to soil drainage

    Science.gov (United States)

    Muamar Rifa'i, Alfian; Setiawan, Bambang; Djarwanti, Noegroho

    2017-12-01

    The expansive soil is soil that has a potential for swelling-shrinking due to changes in water content. Such behavior can exert enough force on building above to cause damage. The use of columns filled with additives such as Calcium Carbide is done to reduce the negative impact of expansive soil behavior. This study aims to determine the effect of carbide columns on expansive soil. Observations were made on swelling and spreading of carbides in the soil. 7 Carbide columns with 5 cm diameter and 20 cm height were installed into the soil with an inter-column spacing of 8.75 cm. Wetting is done through a pipe at the center of the carbide column for 20 days. Observations were conducted on expansive soil without carbide columns and expansive soil with carbide columns. The results showed that the addition of carbide column could reduce the percentage of swelling by 4.42%. Wetting through the center of the carbide column can help spread the carbide into the soil. The use of carbide columns can also decrease the rate of soil expansivity. After the addition of carbide column, the plasticity index value decreased from 71.76% to 4.3% and the shrinkage index decreased from 95.72% to 9.2%.

  1. Strength and Compaction Analysis of Sand-Bentonite-Coal Ash Mixes

    Science.gov (United States)

    Sobti, Jaskiran; Singh, Sanjay Kumar

    2017-08-01

    This paper deals with the strength and compaction characteristics of sand-bentonite-coal ash mixes prepared by varying percentages of sand, bentonite and coal ash to be used in cutoff walls and as a liner or cover material in landfills. The maximum dry density (MDD) and optimum moisture content (OMC) of sand-bentonite mixes and sand-bentonite-coal ash mixes were determined by conducting the standard proctor test. Also, the strength and stiffness characteristics of soil mixes were furnished using unconfined compressive strength test. The results of the study reveal influence of varying percentages of coal ash and bentonite on the compaction characteristics of the sand-bentonite-coal ash mixes. Also, validation of a statistical analysis of the correlations between maximum dry density (MDD), optimum moisture content (OMC) and Specific Gravity (G) was done using the experimental results. The experimental results obtained for sand-bentonite, sand-bentonite-ash and coal ash-bentonite mixes very well satisfied the statistical relations between MDD, OMC and G with a maximum error in the estimate of MDD being within ±1 kN/m3. The coefficient of determination (R2) ranged from 0.95 to 0.967 in case of sand-bentonite-ash mixes. However, for sand-bentonite mixes, the R2 values are low and varied from 0.48 to 0.56.

  2. Poly(norepinephrine)-coated open tubular column for the separation of proteins and recombination human erythropoietin by capillary electrochromatography.

    Science.gov (United States)

    Xiao, Xue; Zhang, Yamin; Wu, Jia; Jia, Li

    2017-12-01

    Recombinant human erythropoietin is an important therapeutic protein with high economic interest due to the benefits provided by its clinical use for the treatment of anemias associated with chronic renal failure and chemotherapy. In this work, a poly(norepinephrine)-coated open tubular column was successfully prepared based on the self-polymerization of norepinephrine under mild alkaline condition, the favorable film forming and easy adhesive properties of poly(norepinephrine). The poly(norepinephrine) coating was characterized by scanning electron microscopy and measurement of the electro-osmotic flow. The thickness of the coating was about 431 nm. The electrochromatographic performance of the poly(norepinephrine)-coated open tubular column was evaluated by separation of proteins. Some basic and acidic proteins including two variants of bovine serum albumin and two variants of β-lactoglobulin achieved separation in the poly(norepinephrine)-coated open tubular column. More importantly, the column demonstrated separation ability for the glycoforms of recombinant human erythropoietin. In addition, the column demonstrated good repeatability with the run-to-run, day-to-day, and column-to-column relative standard deviations of migration times of proteins less than 3.40%. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Gravel Mobility in a High Sand Content Riverbed

    Science.gov (United States)

    Haschenburger, J. K.

    2017-12-01

    In sand-gravel channels, sand may modify gravel transport by changing conditions of entrainment and promoting longer displacements or gravel may inhibit sand transport if concentrated into distinct deposits, which restrict sand supply with consequences for migrating bedform size or form. This study reports on gravel mobility in the lower San Antonio River, Texas, where gravel content in the bed material ranges from about 1% to more than 20%. Sediment transport observations were collected at three U.S. Geological Survey gauging stations by deploying a Helley-Smith sampler with a 0.2 mm mesh bag from which transport rates and mobile grain sizes were determined. The flow rates sampled translate into an annual exceedance expectation from 0.2% to 98%. Gravel transport rates are generally two orders of magnitude smaller than the rates of sand transport. However, the finest gravels are transported at rates on the same order of magnitude as the coarsest sands. At all sites, the 2 and 2.8 mm fractions are transported at the lowest flow rate sampled, suggesting mobility for at least 38% to as much as 98% of the year. Fractions as large as 8 mm are mobilized at flow rates that are expected between 25% and 53% of the year. The largest fractions captured in the sampling (16 to 32 mm) require flows closer to bankfull conditions that occur no more than 0.8% of the year. Results document that some gravel sizes can be frequently transported in low gradient riverbeds with high sand content.

  4. Sand waves on an epicontinental shelf: Northern Bering Sea

    Science.gov (United States)

    Field, M.E.; Nelson, C.H.; Cacchione, D.A.; Drake, D.E.

    1981-01-01

    Sand waves and current ripples occupy the crests and flanks of a series of large linear sand ridges (20 km ?? 5 km ?? 10 m high) lying in an open-marine setting in the northern Bering Sea. The sand wave area, which lies west of Seward Peninsula and southeast of Bering Strait, is exposed to the strong continuous flow of coastal water northward toward Bering Strait. A hierarchy of three sizes of superimposed bedforms, all facing northward, was observed in successive cruises in 1976 and 1977. Large sand waves (height 2 m; spacing 200 m) have smaller sand waves (height 1 m; spacing 20 m) lying at a small oblique angle on their stoss slopes. The smaller sand waves in turn have linguoid ripples on their stoss slopes. Repeated studies of the sand wave fields were made both years with high-resolution seismic-reflection profiles, side-scan sonographs, underwater photographs, current-meter stations, vibracores, and suspended-sediment samplers. Comparison of seismic and side-scan data collected along profile lines run both years showed changes in sand wave shape that indicate significant bedload transport within the year. Gouge marks made in sediment by keels of floating ice also showed significantly different patterns each year, further documenting modification to the bottom by sediment transport. During calm sea conditions in 1977, underwater video and camera observations showed formation and active migration of linguoid and straight-crested current ripples. Current speeds 1 m above the bottom were between 20 and 30 cm/s. Maximum current velocities and sand wave migration apparently occur when strong southwesterly winds enhance the steady northerly flow of coastal water. Many cross-stratified sand bodies in the geologic record are interpreted as having formed in a tidal- or storm-dominated setting. This study provides an example of formation and migration of large bedforms by the interaction of storms with strong uniform coastal currents in an open-marine setting. ?? 1981.

  5. Thermal process of an air column

    International Nuclear Information System (INIS)

    Lee, F.T.

    1994-01-01

    Thermal process of a hot air column is discussed based on laws of thermodynamics. The kinetic motion of the air mass in the column can be used as a power generator. Alternatively, the column can also function as a exhaust/cooler

  6. Charge collection measurements in single-type column 3D sensors

    International Nuclear Information System (INIS)

    Scaringella, M.; Polyakov, A.; Sadrozinski, H.F.-W.; Bruzzi, M.; Tosi, C.; Boscardin, M.; Piemonte, C.; Pozza, A.; Ronchin, S.; Zorzi, N.; Dalla Betta, G.-F.

    2007-01-01

    We report on charge collection studies on 3D silicon detectors of single-type column n-diffusions in p-substrate, configured either as strip or as pad detectors. The charge is generated by penetrating beta particles from a 90 Sr source which, together with a scintillation counter, serves as an electron telescope. The charge collection as a function of bias voltage is compared with the depletion thickness derived from the measured C-V characteristics

  7. Scour at Vertical Piles in Sand-Clay Mixtures under Waves

    DEFF Research Database (Denmark)

    Dey, Subhasish; Helkjær, Anders; Sumer, B. Mutlu

    2011-01-01

    Marine sediments often contain sand-clay mixtures in widely varying proportions. This study presents the results of equilibrium scour and time variation of scour depths at circular piles embedded vertically in clay alone and sand-clay mixed beds under waves. Experiments were conducted in a wave...... flume with different proportions of sand-clay mixtures as bed sediments. Test results for the cases of steady current and sand alone under waves are used as references. The equilibrium scour depth reduces with an increase in clay proportion n (by weight) in a sand-clay mixture. Interestingly, the scour...

  8. Thomson scattering on argon surfatron plasmas at intermediate pressures: Axial profiles of the electron temperature and electron density

    International Nuclear Information System (INIS)

    Palomares, J.M.; Iordanova, E.; Veldhuizen, E.M. van; Baede, L.; Gamero, A.; Sola, A.; Mullen, J.J.A.M. van der

    2010-01-01

    The axial profiles of the electron density n e and electron temperature T e of argon surfatron plasmas in the pressure range of 6-20 mbar and microwave power between 32 and 82 W have been determined using Thomson Scattering of laser irradiation at 532 nm. For the electron density and temperature we found values in the ranges 5 x 10 18 e 19 m -3 and 1.1 e e and T e down to 8% and 3%, respectively. It is found that n e decreases in the direction of the wave propagation with a slope that is nearly constant. The slope depends on the pressure but not on the power. Just as predicted by theories we see that increasing the power leads to longer plasma columns. However, the plasmas are shorter than what is predicted by theories based on the assumption that for the plasma-wave interaction electron-atom collisions are of minor importance (the so-called collisionless regime). The plasma vanishes long before the critical value of the electron density is reached. In contrast to what is predicted by the positive column model it is found that T e does not stay constant along the column, but monotonically increases with the distance from the microwave launcher. Increases of more than 50% over 30 cm were found.

  9. Frac sand in the United States: a geological and industry overview

    Science.gov (United States)

    Benson, Mary Ellen; Wilson, Anna B.; Bleiwas, Donald I.

    2015-01-01

    A new mineral rush is underway in the upper Midwest of the United States, especially in Wisconsin and Minnesota, for deposits of high-quality frac sand that the mining industry calls “Northern White” sand or “Ottawa” sand. Frac sand is a specialized type of sand that is added to fracking fluids that are injected into unconventional oil and gas wells during hydraulic fracturing (fracking or hydrofracking), a process that enhances petroleum extraction from tight (low permeability) reservoirs. Frac sand consists of natural sand grains with strict mineralogical and textural specifications that act as a proppant (keeping induced fractures open), extending the time of release and the flow rate of hydrocarbons from fractured rock surfaces in contact with the wellbore.

  10. Sedimentary controls on modern sand grain coat formation

    Science.gov (United States)

    Dowey, Patrick J.; Worden, Richard H.; Utley, James; Hodgson, David M.

    2017-05-01

    Coated sand grains can influence reservoir quality evolution during sandstone diagenesis. Porosity can be reduced and fluid flow restricted where grain coats encroach into pore space. Conversely pore-lining grain coats can restrict the growth of pore-filling quartz cement in deeply buried sandstones, and thus can result in unusually high porosity in deeply buried sandstones. Being able to predict the distribution of coated sand grains within petroleum reservoirs is thus important to help find good reservoir quality. Here we report a modern analogue study of 12 sediment cores from the Anllóns Estuary, Galicia, NW Spain, collected from a range of sub-environments, to help develop an understanding of the occurrence and distribution of coated grains. The cores were described for grain size, bioturbation and sedimentary structures, and then sub-sampled for electron and light microscopy, laser granulometry, and X-ray diffraction analysis. The Anllóns Estuary is sand-dominated with intertidal sand flats and saltmarsh environments at the margins; there is a shallowing/fining-upwards trend in the estuary-fill succession. Grain coats are present in nearly every sample analysed; they are between 1 μm and 100 μm thick and typically lack internal organisation. The extent of grain coat coverage can exceed 25% in some samples with coverage highest in the top 20 cm of cores. Samples from muddy intertidal flat and the muddy saltmarsh environments, close to the margins of the estuary, have the highest coat coverage (mean coat coverage of 20.2% and 21.3%, respectively). The lowest mean coat coverage occurs in the sandy saltmarsh (10.4%), beyond the upper tidal limit and sandy intertidal flat environments (8.4%), close to the main estuary channel. Mean coat coverage correlates with the concentration of clay fraction. The primary controls on the distribution of fine-grained sediment, and therefore grain coat distribution, are primary sediment transport and deposition processes that

  11. On shelterbelt design for combating sand invasion.

    NARCIS (Netherlands)

    Mohammed, A.E.; Stigter, C.J.; Adam, H.S.

    1996-01-01

    After a review of the scarce literature on using trees against sand encroachment, a quantitative experiment with a wide shelterbelt to combat sand invasion is reported on. Experimental work was carried out at the northwestern border of the Gezira Scheme (Sudan), an area of severe land degradation

  12. Short Communications Sand moisture as a factor determining depth ...

    African Journals Online (AJOL)

    1993-11-05

    Nov 5, 1993 ... The depths to which the animals burrow are, at least partly. determined by the moisture gradient in the sand. They are, however, incapable of burrowing into totally dry sand. Animals alter their position in the sand in response to changes in moisture content so as to ensure exposure to suitable conditions.

  13. Solvent extraction columns

    International Nuclear Information System (INIS)

    Middleton, P.; Smith, J.R.

    1979-01-01

    In pulsed columns for use in solvent extraction processes, e.g. the reprocessing of nuclear fuel, the horizontal perforated plates inside the column are separated by interplate spacers manufactured from metallic neutron absorbing material. The spacer may be in the form of a spiral or concentric circles separated by radial limbs, or may be of egg-box construction. Suitable neutron absorbing materials include stainless steel containing boron or gadolinium, hafnium metal or alloys of hafnium. (UK)

  14. Simulating Sand Behavior through Terrain Subdivision and Particle Refinement

    Science.gov (United States)

    Clothier, M.

    2013-12-01

    Advances in computer graphics, GPUs, and parallel processing hardware have provided researchers with new methods to visualize scientific data. In fact, these advances have spurred new research opportunities between computer graphics and other disciplines, such as Earth sciences. Through collaboration, Earth and planetary scientists have benefited by using these advances in hardware technology to process large amounts of data for visualization and analysis. At Oregon State University, we are collaborating with the Oregon Space Grant and IGERT Ecosystem Informatics programs to investigate techniques for simulating the behavior of sand. In addition, we have also been collaborating with the Jet Propulsion Laboratory's DARTS Lab to exchange ideas on our research. The DARTS Lab specializes in the simulation of planetary vehicles, such as the Mars rovers. One aspect of their work is testing these vehicles in a virtual "sand box" to test their performance in different environments. Our research builds upon this idea to create a sand simulation framework to allow for more complex and diverse environments. As a basis for our framework, we have focused on planetary environments, such as the harsh, sandy regions on Mars. To evaluate our framework, we have used simulated planetary vehicles, such as a rover, to gain insight into the performance and interaction between the surface sand and the vehicle. Unfortunately, simulating the vast number of individual sand particles and their interaction with each other has been a computationally complex problem in the past. However, through the use of high-performance computing, we have developed a technique to subdivide physically active terrain regions across a large landscape. To achieve this, we only subdivide terrain regions where sand particles are actively participating with another object or force, such as a rover wheel. This is similar to a Level of Detail (LOD) technique, except that the density of subdivisions are determined by

  15. Transport of a nonneutral electron plasma due to electron collisions with neutral atoms

    International Nuclear Information System (INIS)

    Douglas, M.H.; O'Neil, T.M.

    1978-01-01

    Transport of a nonneutral electron plasma across a magnetic field is caused by electron scattering from ambient neutral atoms. A theoretical model of such transport is presented, assuming the plasma is quiescent and the scattering is elastic scattering from infinite mass scattering centers of constant momentum transfer cross section. This model is motivated by recent experiments. A reduced transport equation is obtained by expanding the Boltzmann equation for the electron distribution in inverse powers of the magnetic field. The equation together with Poisson's equation for the radial electric field, which must exist in a nonneutral column, determine the evolution of the system. When these two equations are properly scaled, they contain only a single parameter: the ratio of initial Debye length to initial column radius. For cases where this parameter is either large or small, analytical solutions, or at least partial solutions, are obtained. For intermediate values of the parameter, numerical solutions are obtained

  16. SPECIFIC RESISTANCE AND SPECIFIC INTENSITY OF BELT SANDING OF WOOD

    Directory of Open Access Journals (Sweden)

    Boleslaw Porankiewicz

    2010-06-01

    Full Text Available This paper examines and discusses the specific belt sanding resistance K (N·cm-2 and specific belt sanding intensity SI (g·cm-2·min-1, for wood of Pinus sylvestris L., Picea abies L., Quercus robra L., Acer pseudoplatanus L., Alnus glutinosa Gaertn., and Populus Nigra L., by different sanding pressure pS, different sanding grit NG number, and different wood grain angles Phi(v.

  17. Sand (CSW4)

    CSIR Research Space (South Africa)

    Estuarine and Coastal Research Unit

    1982-12-01

    Full Text Available This report is one of a series on Cape Estuaries being published under the general title "The Estuaries of the Cape, Part 2". The report provides information on sand estuary: historical background, abiotic and biotic characteristics. It is pointed...

  18. The extraction of bitumen from western oil sands

    International Nuclear Information System (INIS)

    Oblad, A.G.; Bunger, J.W.; Dahlstrom, D.A.; Deo, M.D.; Hanson, F.V.; Miller, J.D.; Seader, J.D.

    1992-08-01

    The University of Utah tar sand research and development program is concerned with research and development on Utah is extensive oil sands deposits. The program has been intended to develop a scientific and technological base required for eventual commercial recovery of the heavy oils from oil sands and processing these oils to produce synthetic crude oil and other products such as asphalt. The overall program is based on mining the oil sand, processing the mined sand to recover the heavy oils and upgrading them to products. Multiple deposits are being investigated since it is believed that a large scale (approximately 20,000 bbl/day) plant would require the use of resources from more than one deposit. The tasks or projects in the program are organized according to the following classification: Recovery technologies which includes thermal recovery methods, water extraction methods, and solvent extraction methods; upgrading and processing technologies which covers hydrotreating, hydrocracking, and hydropyrolysis; solvent extraction; production of specialty products; and environmental aspects of the production and processing technologies. These tasks are covered in this report

  19. Fate of 17β-estradiol and 17α-ethinylestradiol in batch and column studies simulating managed aquifer recharge

    KAUST Repository

    Maeng, Sungkyu

    2013-11-01

    Laboratory-scale batch and soil columns experiments were conducted to investigate the attenuation of estrogens (17β-estradiol and 17α-ethinylestradiol) during managed aquifer recharge. The role of microbial activity in the removal of selected estrogens was evaluated by comparing the results from biotic and abiotic batch experiments. Moreover, batch experiments were carried out using the sand media prepared over different acclimation periods to investigate the impact of acclimation periods on the removal of selected estrogens. Batch studies showed that adsorption was the dominant removal mechanism in the removal of 17β-estradiol and 17α-ethinylestradiol. 17β-estradiol and 17α-ethinylestradiol were attenuated by 99% and 96%, respectively, in batch experiments under oxic conditions. Redox conditions did not show any significant effect on the attenuation of 17β-estradiol. However, the net estrogenicity of 17β-estradiol remaining was lower under oxic conditions (130 ng estradiol-equivalents/L) than anoxic conditions (970 ng estradiol-equivalents/L) . Column studies operated at 17 h of empty bed contact time also demonstrated that removal mechanism of 17α-ethinylestradiol was more dependent on adsorption than biodegradation. © IWA Publishing 2013.

  20. Preparation and evaluation of a novel hybrid monolithic column based on pentafluorobenzyl imidazolium bromide ionic liquid.

    Science.gov (United States)

    Shan, Yuanhong; Qiao, Lizhen; Shi, Xianzhe; Xu, Guowang

    2015-01-02

    To develop a novel hybrid monolithic column based on pentafluorobenzyl imidazolium bromide ionic liquid, a new ionic liquid monomer was synthesized from 1-vinylimidazole and pentafluorobenzyl bromide. By employing a facile one-step copolymerization of polyhedral-oligomeric-silsesquioxane-type (POSS) cross-linking agent and the home-made ionic liquid monomer, the hybrid monolithic columns were in situ fabricated in fused-silica capillary. The morphology of monolithic column was characterized by scanning electron microscope (SEM) and the chemical composition was confirmed by Fourier-transform infrared spectroscopy (FT-IR) and elemental analysis. Excellent mechanical stability and slight swelling propensity were exhibited which was ascribed to the rigid hybrid monolithic skeleton. Reproducibility results of run-to-run, column-to-column, batch-to-batch and day-to-day were investigated and the RSDs were less than 0.46%, 1.84%, 3.96% and 3.17%, respectively. The mixed-mode retention mechanism with hydrophobic interaction, π-π stacking, ion-exchange, electrostatic interaction and dipole-dipole interaction was explored systematically using analytes with different structure types. Satisfied separation capability and column efficiency were achieved for the analysis of small molecular compounds such as alkylbenzenes, polycyclic aromatic hydrocarbons, nucleosides and halogenated compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Column ratio mapping: a processing technique for atomic resolution high-angle annular dark-field (HAADF) images.

    Science.gov (United States)

    Robb, Paul D; Craven, Alan J

    2008-12-01

    An image processing technique is presented for atomic resolution high-angle annular dark-field (HAADF) images that have been acquired using scanning transmission electron microscopy (STEM). This technique is termed column ratio mapping and involves the automated process of measuring atomic column intensity ratios in high-resolution HAADF images. This technique was developed to provide a fuller analysis of HAADF images than the usual method of drawing single intensity line profiles across a few areas of interest. For instance, column ratio mapping reveals the compositional distribution across the whole HAADF image and allows a statistical analysis and an estimation of errors. This has proven to be a very valuable technique as it can provide a more detailed assessment of the sharpness of interfacial structures from HAADF images. The technique of column ratio mapping is described in terms of a [110]-oriented zinc-blende structured AlAs/GaAs superlattice using the 1 angstroms-scale resolution capability of the aberration-corrected SuperSTEM 1 instrument.

  2. Column ratio mapping: A processing technique for atomic resolution high-angle annular dark-field (HAADF) images

    International Nuclear Information System (INIS)

    Robb, Paul D.; Craven, Alan J.

    2008-01-01

    An image processing technique is presented for atomic resolution high-angle annular dark-field (HAADF) images that have been acquired using scanning transmission electron microscopy (STEM). This technique is termed column ratio mapping and involves the automated process of measuring atomic column intensity ratios in high-resolution HAADF images. This technique was developed to provide a fuller analysis of HAADF images than the usual method of drawing single intensity line profiles across a few areas of interest. For instance, column ratio mapping reveals the compositional distribution across the whole HAADF image and allows a statistical analysis and an estimation of errors. This has proven to be a very valuable technique as it can provide a more detailed assessment of the sharpness of interfacial structures from HAADF images. The technique of column ratio mapping is described in terms of a [1 1 0]-oriented zinc-blende structured AlAs/GaAs superlattice using the 1 A-scale resolution capability of the aberration-corrected SuperSTEM 1 instrument.

  3. Electron Density in Atmospheric Pressure Microwave Surface Wave Discharges

    International Nuclear Information System (INIS)

    Jasinski, M.; Zakrzewski, Z.; Mizeraczyk, J.

    2008-01-01

    In this paper, we present results of the spectroscopic measurements of the electron density in a microwave surface wave sustained discharges in Ar and Ne at atmospheric pressure. The discharge in the form of a plasma column was generated inside a quartz tube cooled with a dielectric liquid. The microwave power delivered to the discharge via rectangular waveguide was applied in the range of 200-1500 W. In all investigations presented in this paper, the gas flow rate was relatively low (0.5 l/min), so the plasma column was generated in the form of a single filament, and the lengths of the upstream and downstream plasma columns were almost the same. The electron density in the plasma columns was determined using the method based on the Stark broadening of H β spectral line, including plasma region inside the waveguide which was not investigated earlier

  4. Hydraulic conductivity of indeformed soil columns determination by gamma ray transmission

    International Nuclear Information System (INIS)

    Moreira, Anderson Camargo; Moraes Cavalcante, Fabio Henrique de; Rocha, Marcos Correa da; Filho, Otavio Portezan; Quinones, Fernando Rodolfo Espinosa; Appoloni, Carlos Roberto

    2000-01-01

    The spatial variation of the soil structure influences the water movement through its porous geometry, which could cause problems in the development of agricultural cultures and also accelerate processes of soil erosion. The gamma ray transmission method has established efficiency for the non-destructive measurement of moisture temporal and space evolution, and consequently in the determination of the hydraulic conductivity of the soil, K(θ). Columns of undisturbed soil (approximately 0.11 x 0.06 x 0.60 m) were removed from a trench in the Campus of Londrina State University. The used soil was classified like distrophic dark red soil (LRd). The indeformed soil columns were wrapped up with paraffin and gauze and were fixed on the table of measurement. The water vertical infiltration in the soil was accomplished by maintaining a water layer of approximately 0.01 m over an area of soil of 75 x 10 -4 m 2 . Layers of filter papers and foam controlled the flow of water in the soil surface. After the conclusion of the infiltration, began the process of redistribution of the water in the soil column, with the objective to determine the function K(θ) in relation to the depth in the column. The moisture profiles θ(z,t) are obtained using a radioactive source of 241 Am (3.7 x 10 9 Bq; 0.0596 MeV), spectrometric electronic chain, a 2x2'' NaI(Tl) detector and a measurements table , which allows the sample to move vertically. The hydraulic conductivity function was determined, applying the Sisson model , at 10 levels in the soil column and the results exhibit an increase of K(θ) with depth. (author)

  5. SANDS: a service-oriented architecture for clinical decision support in a National Health Information Network.

    Science.gov (United States)

    Wright, Adam; Sittig, Dean F

    2008-12-01

    In this paper, we describe and evaluate a new distributed architecture for clinical decision support called SANDS (Service-oriented Architecture for NHIN Decision Support), which leverages current health information exchange efforts and is based on the principles of a service-oriented architecture. The architecture allows disparate clinical information systems and clinical decision support systems to be seamlessly integrated over a network according to a set of interfaces and protocols described in this paper. The architecture described is fully defined and developed, and six use cases have been developed and tested using a prototype electronic health record which links to one of the existing prototype National Health Information Networks (NHIN): drug interaction checking, syndromic surveillance, diagnostic decision support, inappropriate prescribing in older adults, information at the point of care and a simple personal health record. Some of these use cases utilize existing decision support systems, which are either commercially or freely available at present, and developed outside of the SANDS project, while other use cases are based on decision support systems developed specifically for the project. Open source code for many of these components is available, and an open source reference parser is also available for comparison and testing of other clinical information systems and clinical decision support systems that wish to implement the SANDS architecture. The SANDS architecture for decision support has several significant advantages over other architectures for clinical decision support. The most salient of these are:

  6. PULSE COLUMN

    Science.gov (United States)

    Grimmett, E.S.

    1964-01-01

    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  7. Permeability Characteristics of Compacted and Stabilized Clay with Cement, Peat Ash and Silica Sand

    Directory of Open Access Journals (Sweden)

    Seyed Esmaeil Mousavi

    2016-06-01

    Full Text Available The present paper investigates the influence of stabilization with cement, peat ash, and silica sand on permeability coefficient (kv of compacted clay, using a novel approach to stabilize the clay with peat ash as a supplementary material of cement in the compacted and stabilized soil. In order to assess the mentioned influence, test specimens of both untreated and stabilized soil have been tested in the laboratory so that their permeability could be evaluated. Falling head and one dimensional consolidation tests of laboratory permeability were performed on the clay specimens and the chemical compositions of the materials as well as microstructure of the stabilized soil with 18% cement, 2% peat ash, and 5% silica sand were investigated, using X-ray fluorescence and scanning electron microscopy respectively. Results show that for soil stabilization with up to 8% cement content (of the dry weight of the soil, the average value of coefficient of permeability (kv is very close to that of untreated soil, whereas the kv value decreases drastically for 18% cement under identical void ratio conditions. It is further revealed that addition of 18% cement, 2% peat ash, and 5% silica sand had decreased the coefficient of permeability by almost 2.2 folds after 24 h, while about 1.7 folds increase was observed in coefficient of permeability once 13.5% of cement, 1.5% of peat ash, and 20% of silica sand were added. The partial replacement of cement with the 2% peat ash can reduce the consumption of cement for soil stabilization.

  8. Evaluation of sand reserves in del Plata City

    International Nuclear Information System (INIS)

    Loureiro, J.

    2014-01-01

    The purpose of this study is to evaluate the reserve of sand in the zone of del Plata city and beyond. This area is located in the S E edge of the department of San Jose near the mouth of Santa Lucia river. In this zone was identified the mantle of potentially exploitable sand which are based on their particle size, composition and depth of the limits cape. There are two powerful capes of sand separated by clay and silt

  9. Seasonal fluctuations of phlebotomines sand fly populations ...

    African Journals Online (AJOL)

    An entomological survey of phlebotomine sand flies was conducted in the Moulay Yacoub province, central Morocco. An anthropic niche (Ouled Aid) and a wild niche (Zliligh) were selected. Sand flies were collected twice a month between April 2011 and March 2012, using sticky traps and CDC light traps. 3675 specimens ...

  10. Comparative evaluation of post-column free radical scavenging and ferric reducing antioxidant power assays for screening of antioxidants in strawberries.

    Science.gov (United States)

    Raudonis, Raimondas; Raudone, Lina; Jakstas, Valdas; Janulis, Valdimaras

    2012-04-13

    ABTS and FRAP post-column techniques evaluate the antioxidant characteristics of HPLC separated compounds with specific reagents. ABTS characterize their ability to scavenge free radicals by electron-donating antioxidants, resulting in the absorbance decrease of the chromophoric radical. FRAP - is based on the reduction of Fe(III)-tripyridyltriazine complex to Fe(II)-tripyridyltriazine at low pH by electron-donating antioxidants, resulting in an absorbance increase. Both post-column assays were evaluated and compared according to the following validation parameters: specificity, precision, limit of detection (LoD), limit of quantitation (LoQ) and linearity. ABTS and FRAP post-column assays were specific, repeatable and sensitive and thus can be used for the evaluation of antioxidant active compounds. Antioxidant active compounds were quantified according to TEAC for each assay and ABTS/FRAP ratio was derived. No previous records of antioxidative activity of leaves and fruits of strawberries (Fragaria viridis, Fragaria moschata) research have been found. The research results confirm the reliability of ABTS and FRAP post-column assays for screening of antioxidants in complex mixtures and the determination of radical scavenging and ferric reducing ability by their TEAC values. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Molecular Diversity between Salivary Proteins from New World and Old World Sand Flies with Emphasis on Bichromomyia olmeca, the Sand Fly Vector of Leishmania mexicana in Mesoamerica.

    Science.gov (United States)

    Abdeladhim, Maha; V Coutinho-Abreu, Iliano; Townsend, Shannon; Pasos-Pinto, Silvia; Sanchez, Laura; Rasouli, Manoochehr; B Guimaraes-Costa, Anderson; Aslan, Hamide; Francischetti, Ivo M B; Oliveira, Fabiano; Becker, Ingeborg; Kamhawi, Shaden; Ribeiro, Jose M C; Jochim, Ryan C; Valenzuela, Jesus G

    2016-07-01

    Sand fly saliva has been shown to have proteins with potent biological activities, salivary proteins that can be used as biomarkers of vector exposure, and salivary proteins that are candidate vaccines against different forms of leishmaniasis. Sand fly salivary gland transcriptomic approach has contributed significantly to the identification and characterization of many of these salivary proteins from important Leishmania vectors; however, sand fly vectors in some regions of the world are still neglected, as Bichromomyia olmeca (formerly known as Lutzomyia olmeca olmeca), a proven vector of Leishmania mexicana in Mexico and Central America. Despite the importance of this vector in transmitting Leishmania parasite in Mesoamerica there is no information on the repertoire of B. olmeca salivary proteins and their relationship to salivary proteins from other sand fly species. A cDNA library of the salivary glands of wild-caught B. olmeca was constructed, sequenced, and analyzed. We identified transcripts encoding for novel salivary proteins from this sand fly species and performed a comparative analysis between B. olmeca salivary proteins and those from other sand fly species. With this new information we present an updated catalog of the salivary proteins specific to New World sand flies and salivary proteins common to all sand fly species. We also report in this work the anti-Factor Xa activity of Lofaxin, a salivary anticoagulant protein present in this sand fly species. This study provides information on the first transcriptome of a sand fly from Mesoamerica and adds information to the limited repertoire of salivary transcriptomes from the Americas. This comparative analysis also shows a fast degree of evolution in salivary proteins from New World sand flies as compared with Old World sand flies.

  12. A Primer on Alberta’s Oil sands Royalties

    Directory of Open Access Journals (Sweden)

    Sarah Dobson

    2015-12-01

    Full Text Available Fulfilling its campaign promise, the new NDP government announced a review of Alberta’s royalty framework in June 2015. The province receives royalty revenue from three main sources – natural gas, crude oil, and oil sands. Since the 2009-10 fiscal year the largest contributor to Alberta’s royalty revenues has been the oil sands. If you want a sense of how important oil sands royalties have been for Alberta’s finances, consider this: In the 2014–15 fiscal year, the government collected just over $5 billion from oil sands royalties. These royalties covered over 10 per cent of the province’s operational expenses of $48.6 billion in the same fiscal year. Over the last six fiscal years the oil sands have contributed an average of 10 per cent of revenues to provincial coffers. This makes oil sands royalties the fourth largest contributor behind personal income taxes (23 per cent, federal transfers (13 per cent and corporate income taxes (11 per cent. But how many Albertans really understand how the royalty system works? What do we mean when we say “royalty”? How does the Alberta Government calculate royalties on oil sands producers? If the system is going to change, it’s important that Albertans understand how the current system works. That is what this paper is designed to do. For Albertans to properly judge the impact of new policy, they need a solid understanding of the current policy environment. We all know that oil prices have dropped and oil sands producers are losing profitability. As such, changes to the royalty system could have a deep and profound impact on the sector. Here are some of the issues this primer will study: • Pre-payout projects vs. post-payout projects, in other words, the classification of projects for royalty purposes based on whether the cumulative costs of a project exceed its cumulative revenues • Monthly payment of royalties vs. annual payment • Understanding the unit price of bitumen and how that

  13. Performance of RC columns with partial length corrosion

    International Nuclear Information System (INIS)

    Wang Xiaohui; Liang Fayun

    2008-01-01

    Experimental and analytical studies on the load capacity of reinforced concrete (RC) columns with partial length corrosion are presented, where only a fraction of the column length was corroded. Twelve simply supported columns were eccentrically loaded. The primary variables were partial length corrosion in tensile or compressive zone and the corrosion level within this length. The failure of the corroded column occurs in the partial length, mainly developed from or located nearby or merged with the longitudinal corrosion cracks. For RC column with large eccentricity, load capacity of the column is mainly influenced by the partial length corrosion in tensile zone; while for RC column with small eccentricity, load capacity of the column greatly decreases due to the partial length corrosion in compressive zone. The destruction of the longitudinally mechanical integrality of the column in the partial length leads to this great reduction of the load capacity of the RC column

  14. Sand ramps as palaeoenvironmental archives: Integrating general principles and regional contexts through reanalysis of the Klipkraal Sands, South Africa

    Science.gov (United States)

    Rowell, Alexandra L. K.; Thomas, David S. G.; Bailey, Richard M.; Holmes, Peter J.

    2018-06-01

    Sand ramps occur on a continuum of topographically-controlled landforms, ranging from purely aeolian features (climbing/falling dunes) to talus cones and alluvial fans. Sand ramps have been identified as potentially important palaeoenvironmental archives in dryland regions that possess relatively few Quaternary proxy records. Their utility however requires not only good age control of depositional phases but clear identification of process regimes, determined through morphological and sedimentological analyses, with several recent studies indicating the complexities of palaeoenvironmental interpretations and the controls of ramp development (Bateman et al., 2012; Rowell et al., 2018). Klipkraal Sands is a sand ramp on the north-eastern margin of the semi-arid Karoo that has been important for inferences of the extent of southern African Late Quaternary aeolian activity (Thomas et al., 2002). We reanalyse this feature, in the light of both its significance and other recent studies that have inferred extensive southern African LGM aeolian activity (Telfer et al., 2012, 2014). New sedimentological data and twelve OSL dates indicate the Klipkraal Sands formed episodically between 100-0.14 ka, rather than accumulating rapidly, while sedimentological data question the aeolian affinities of the bulk of the feature. Therefore, Klipkraal is reinterpreted as showing no particular affinity to the LGM, with sediments locally sourced with a significant colluvial component. Only the upper historical sediments can be clearly interpreted as aeolian deposits. A complex interplay of processes is suggested, for which a meaningful palaeoenvironmental interpretation cannot be easily defined. This implies that the local geomorphic processes and controls operating on sand ramps need to be established before they can be fully utilised as palaeoenvironmental archives, with implications for their interpretation worldwide.

  15. Heavy mineral concentration from oil sand tailings

    Energy Technology Data Exchange (ETDEWEB)

    Chachula, F.; Erasmus, N. [Titanium Corp. Inc., Regina, SK (Canada)

    2008-07-01

    This presentation described a unique technique to recover heavy minerals contained in the froth treatment tailings produced by oil sand mining extraction operations in Fort McMurray, Alberta. In an effort to process waste material into valuable products, Titanium Corporation is developing technology to recover heavy minerals, primarily zircon, and a portion of bitumen contained in the final stage of bitumen processing. The process technology is being developed to apply to all mined oil sands operations in the Fort McMurray region. In 2004, Titanium Corporation commissioned a pilot research facility at the Saskatchewan Research Council to test dry oil sands tailings. In 2005, a bulk sampling pilot plant was connected to the fresh oil sands tailings pipeline on-site in Fort McMurray, where washed sands containing heavy minerals were processed at a pilot facility. The mineral content in both deposited tailings and fresh pipeline tailings was assessed. Analysis of fresh tailings on a daily basis identified a constant proportion of zircon and higher levels of associated bitumen compared with the material in the deposited tailings. The process flow sheet design was then modified to remove bitumen from the heavy minerals and concentrate the minerals. A newly modified flotation process was shown to be a viable processing route to recover the heavy minerals from froth treatment tailings. 8 refs., 9 tabs., 12 figs.

  16. Transmission electron microscope CCD camera

    Science.gov (United States)

    Downing, Kenneth H.

    1999-01-01

    In order to improve the performance of a CCD camera on a high voltage electron microscope, an electron decelerator is inserted between the microscope column and the CCD. This arrangement optimizes the interaction of the electron beam with the scintillator of the CCD camera while retaining optimization of the microscope optics and of the interaction of the beam with the specimen. Changing the electron beam energy between the specimen and camera allows both to be optimized.

  17. Quality stabilisation of synthetic sand containing bentonite in process lines

    OpenAIRE

    A. Fedoryszyn

    2010-01-01

    Stabilisation of sand quality requires the monitoring and control of sand moisture contents and its other parameters at each stage of sandprocessing, i.e. during the preparation of return sand mix and rebonding processes. Stabilisation of sand quality necessitates the use of reliable control equipment and evaluation procedures. This study outlines the scope and results of research work aimed to improve the control equipment to enhance the performance of turbine mixers. The paper reviews the m...

  18. Sand transport, erosion and granular electrification

    DEFF Research Database (Denmark)

    Merrison, J.P.

    2012-01-01

    is expanding our current understanding and outline the areas of advancement needed in the future. Presentation is made of current models for wind driven detachment/entrainment and the transport rates of sand and dust, including the effects of contact induced grain electrification. This ubiquitous phenomenon...... can affect grain transport through the generation of intense electric fields and processes of electrostatic assembly. Importantly the transport of sand is characterized by saltation, which is known to be an active process for erosion and therefore a source for dust and sand formation. Using novel...... erosion simulation techniques the link between grain transport rates and erosion rates has been quantified. Furthermore this can be linked to production rates for dust and has been associated with chemical and mineral alteration through a process of mechanical activation of fractured surfaces. This work...

  19. Study on Production of Silicon Nanoparticles from Quartz Sand for Hybrid Solar Cell Applications

    Science.gov (United States)

    Arunmetha, S.; Vinoth, M.; Srither, S. R.; Karthik, A.; Sridharpanday, M.; Suriyaprabha, R.; Manivasakan, P.; Rajendran, V.

    2018-01-01

    Nano silicon (nano Si) particles were directly prepared from natural mineral quartz sand and thereafter used to fabricate the hybrid silicon solar cells. Here, in this preparation technique, two process stages were involved. In the first stage, the alkaline extraction and acid precipitation processes were applied on quartz sand to fetch silica nanoparticles. In the second stage, magnesiothermic and modified magnesiothermic reduction reactions were applied on nano silica particles to prepare nano Si particles. The effect of two distinct reduction methodologies on nano Si particle preparation was compared. The magnesiothermic and modified magnesiothermic reductions in the silica to silicon conversion process were studied with the help of x-ray diffraction (XRD) with intent to study the phase changes during the reduction reaction as well as its crystalline nature in the pure silicon phase. The particles consist of a combination of fine particles with spherical morphology. In addition to this, the optical study indicated an increase in visible light absorption and also increases the performance of the solar cell. The obtained nano Si particles were used as an active layer to fabricate the hybrid solar cells (HSCs). The obtained results confirmed that the power conversion efficiency (PCE) of the magnesiothermically modified nano Si cells (1.06%) is much higher as compared to the nano Si cells that underwent magnesiothermic reduction (1.02%). Thus, this confirms the increased PCE of the investigated nano Si solar cell up to 1.06%. It also revealed that nano Si behaved as an electron acceptor and transport material. The present study provided valuable insights and direction for the preparation of nano Si particles from quartz sand, including the influence of process methods. The prepared nano Si particles can be utilized for HSCs and an array of portable electronic devices.

  20. Aeolian sand transport and aeolian deposits on Venus: A review

    Science.gov (United States)

    Kreslavsly, Mikhail A.; Bondarenko, Nataliya V.

    2017-06-01

    We review the current state of knowledge about aeolian sand transport and aeolian bedforms on planet Venus. This knowledge is limited by lack of observational data. Among the four planetary bodies of the Solar System with sufficient atmospheres in contact with solid surfaces, Venus has the densest atmosphere; the conditions there are transitional between those for terrestrial subaerial and subaqueous transport. The dense atmosphere causes low saltation threshold and short characteristic saltation length, and short scale length of the incipient dunes. A few lines of evidence indicate that the typical wind speeds exceed the saltation threshold; therefore, sand transport would be pervasive, if sand capable of saltation is available. Sand production on Venus is probably much slower than on the Earth; the major terrestrial sand sinks are also absent, however, lithification of sand through sintering is expected to be effective under Venus' conditions. Active transport is not detectable with the data available. Aeolian bedforms (transverse dunes) resolved in the currently available radar images occupy a tiny area on the planet; however, indirect observations suggest that small-scale unresolved aeolian bedforms are ubiquitous. Aeolian transport is probably limited by sand lithification causing shortage of saltation-capable material. Large impact events likely cause regional short-term spikes in aeolian transport by supplying a large amount of sand-size particles, as well as disintegration and activation of older indurated sand deposits. The data available are insufficient to understand whether the global aeolian sand transport occurs or not. More robust knowledge about aeolian transport on Venus is essential for future scientific exploration of the planet, in particular, for implementation and interpretation of geochemical studies of surface materials. High-resolution orbital radar imaging with local to regional coverage and desirable interferometric capabilities is the

  1. 29 CFR 1926.755 - Column anchorage.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Column anchorage. 1926.755 Section 1926.755 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Steel Erection § 1926.755 Column anchorage. (a) General requirements for erection stability. (1) All columns shall be anchored by a minimum of 4 anchor...

  2. Adsorption columns for use in radioimmunoassays

    International Nuclear Information System (INIS)

    1976-01-01

    Adsorption columns are provided which can be utilized in radioimmunoassay systems such as those involving the separation of antibody-antigen complexes from free antigens. The preparation of the columns includes the treatment of retaining substrate material to render it hydrophilic, preparation and degassing of the separation material and loading the column

  3. Geomorphology and drift potential of major aeolian sand deposits in Egypt

    Science.gov (United States)

    Hereher, Mohamed E.

    2018-03-01

    Aeolian sand deposits cover a significant area of the Egyptian deserts. They are mostly found in the Western Desert and Northern Sinai. In order to understand the distribution, pattern and forms of sand dunes in these dune fields it is crucial to analyze the wind regimes throughout the sandy deserts of the country. Therefore, a set of wind data acquired from twelve meteorological stations were processed in order to determine the drift potential (DP), the resultant drift potential (RDP) and the resultant drift direction (RDD) of sand in each dune field. The study showed that the significant aeolian sand deposits occur in low-energy wind environments with the dominance of linear and transverse dunes. Regions of high-energy wind environments occur in the south of the country and exhibit evidence of deflation rather than accumulation with the occurrence of migratory crescentic dunes. Analysis of the sand drift potentials and their directions help us to interpret the formation of major sand seas in Egypt. The pattern of sand drift potential/direction suggests that the sands in these seas might be inherited from exogenous sources.

  4. Two-fold sustainability – Adobe with sawdust as partial sand replacement

    Science.gov (United States)

    Jokhio, Gul A.; Syed Mohsin, Sharifah M.; Gul, Yasmeen

    2018-04-01

    Adobe is a material that is economic, environment friendly, and provides better indoor air quality. The material required for the preparation of adobe include clay, sand, and sometimes straw or other organic materials. These materials do not require industrial processing or transportation, however, sand mining has been recently posing a threat to the environment. Therefore, to enhance the existing sustainability of adobe, sand can be partially or fully replaced by other waste materials. This approach will not only solve the problem of excessive sand mining, it will also address the issue of waste management. Sawdust is one such waste material that can be used to partially replace sand in Adobe. This paper presents the results of compressive and flexural test carried out on Adobe samples with partial sand replacement by sawdust. The results show that about 4% sand replacement by volume produces higher compressive strength, whereas the flexural strength reduces with the use of sawdust. However, since flexural strength is not a critical property for adobe, it is concluded that replacing sand with sawdust by about 4% of volume will be beneficial.

  5. Dissolution enhancement and mathematical modeling of removal of residual trichloroethene in sands by ozonation during flushing with micro-nano-bubble solution

    Science.gov (United States)

    Sung, Menghau; Teng, Chun-Hao; Yang, Tsung-Hsien

    2017-07-01

    Soil flushing using micro-nano-sized bubbles (MNB) in water as the flushing solution was tested in laboratory sand columns for the cleanup of residual trichloroethene (TCE) non-aqueous-phase-liquid (NAPL). Experiments considering flushing with MNB as well as ozone MNB (OZMNB) in water to treat soils contaminated with residual TCE liquid were conducted to examine effects of ozone on dissolution enhancement. The degrees of residual TCE saturation in soils, ranging from 0.44% to 7.6%, were tested. During flushings, aqueous TCE concentrations at the column exit were monitored and TCE masses remained in the columns after flushing were determined. Experimental results between runs with MNB and OZMNB in water revealed that dissolution enhancement was dependent on residual saturation conditions, and the maximum enhancement was around 9%. Governing equations consisting of three coupled partial differential equations (PDEs) were developed to model the system, and high-order finite difference (HOFD) method was employed to solve these PDEs. From mathematical modeling of reactive mass transfer under low residual saturation conditions (0.44% and 1.9%), experimental data were simulated and important controlling mechanisms were identified. It was concluded that a specific parameter pertinent to NAPL-water interfacial area in the Sherwood number had to be modified to satisfactorily describe the dissolution of TCE in the presence of MNB in water.

  6. The importance of sand in the formation of avulsion channels within experimental fans that develop from sediment mixtures of mud and sand

    Science.gov (United States)

    Iscen, N.; Strom, K.

    2017-12-01

    Autogenic channel migration and avulsion has long been recognized as important drivers of alluvial fan dynamics. In the literature, several field studies have documented that the presence and the amount of sand transport through a channel is important for channel incision in alluvial fans and deltas. In our experiments, we present the general autogenic avulsion cycle of experimental alluvial fans with mixtures of cohesive sediment and sand with a range of boundary conditions, and we detail the importance of mobile sand fraction in the development of channels that lead to avulsion. Experimental observations demonstrate that new channels form at topographically low regions within the floodplain providing that sand is transported to these topographic lows due to overbank flow or levee breaching. In addition to the sediment transported from upstream, erosion of a previous deposit and an ongoing backfilling nearby are observed as the possible sources of sand getting into the ghost channels. We explore whether the presence of sand is important for channel development because it increases abrasion of the channel or because it changes the roughness characteristics of the flow. We also examine the affect of sediment and water supply change on the newly described channelization process and link distinctive channel morphologies to different stages of described channel development and the avulsion process.

  7. NMFS Water Column Sonar Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water column sonar data are an important component of fishery independent surveys, habitat studies and other research. NMFS water column sonar data are archived here.

  8. Rheology of oil sands slurries

    Energy Technology Data Exchange (ETDEWEB)

    Chow, R.; Zhou, J. [Alberta Research Council, Edmonton, AB (Canada). Mineral Oil Sands Unit; Wallace, D. [Dean Wallace Consulting Inc., Beaumont, AB (Canada)

    2006-07-01

    This study focused on integrating rheology and colloid science to improve recovery of bitumen in surface mined oil sands. Factors that influence recovery, such as conditions of particle interaction, solids concentration and shear rate, were reviewed. In an effort to understand the rheological behaviour of clay-in-water suspensions, an elaborate procedure was developed to separate an inter-bedded clay layer from a site at Albian Sands Energy Inc. The variables were water chemistry, solids concentration, and shear rate. The research study was conducted at the Alberta Research Council with the support of the CONRAD Extraction Group. A controlled stress rheometer was used to provide the quantitative evaluations of the clay slurry properties. The research results indicate that the viscoelastic properties of the slurry are highly influenced by the shear history of the slurry, solids content, calcium concentration, and sample aging. Shear thinning behaviour was observed in all slurry samples, but the slurry viscosity increased with test time for a given shear rate. In order to classify the slurries, a method was developed to distinguish the gel strength. The slurries were then classified into 3 distinct patterns, including no gel, weak gel and strong gel. The evolution of the experimental protocols were described along with the current stability maps that correlate the domains of the gel strength according to the solids concentration, calcium ion content, and shear rate. It was concluded that the rheological properties of oil sands slurries influence bitumen recovery in commercial surface-mined oil sands operations. tabs., figs.

  9. Production of oil from Intermountain West tar sands deposits

    Energy Technology Data Exchange (ETDEWEB)

    Glassett, J.M.; Glassett, J.A.

    1976-03-01

    Six tar sand deposits in the Intermountain West, each containing more than one billion barrels of oil in place, are identified. All of these deposits are in eastern Utah and contain a total of twenty-eight billion barrels of oil. The names of the six deposits arranged in descending order of desirability for large-scale surface-mining oil recovery operations are as follows: Sunnyside, Tar Sand Triangle, Asphalt Ridge, P.R. Spring, Circle Cliffs, and Hill Creek. An overview of each deposit is presented including geology, surface-mining variables, chemical processing variables, environmental aspects, and economics. A comparison of Utah tar sands and Athabasca, Alberta, Canada tar sands is also presented.

  10. Sand and Gravel Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes sand and gravel operations in the United States. These data were obtained from information reported voluntarily to the USGS by the aggregate...

  11. A Threshold Continuum for Aeolian Sand Transport

    Science.gov (United States)

    Swann, C.; Ewing, R. C.; Sherman, D. J.

    2015-12-01

    The threshold of motion for aeolian sand transport marks the initial entrainment of sand particles by the force of the wind. This is typically defined and modeled as a singular wind speed for a given grain size and is based on field and laboratory experimental data. However, the definition of threshold varies significantly between these empirical models, largely because the definition is based on visual-observations of initial grain movement. For example, in his seminal experiments, Bagnold defined threshold of motion when he observed that 100% of the bed was in motion. Others have used 50% and lesser values. Differences in threshold models, in turn, result is large errors in predicting the fluxes associated with sand and dust transport. Here we use a wind tunnel and novel sediment trap to capture the fractions of sand in creep, reptation and saltation at Earth and Mars pressures and show that the threshold of motion for aeolian sand transport is best defined as a continuum in which grains progress through stages defined by the proportion of grains in creep and saltation. We propose the use of scale dependent thresholds modeled by distinct probability distribution functions that differentiate the threshold based on micro to macro scale applications. For example, a geologic timescale application corresponds to a threshold when 100% of the bed in motion whereas a sub-second application corresponds to a threshold when a single particle is set in motion. We provide quantitative measurements (number and mode of particle movement) corresponding to visual observations, percent of bed in motion and degrees of transport intermittency for Earth and Mars. Understanding transport as a continuum provides a basis for revaluating sand transport thresholds on Earth, Mars and Titan.

  12. Investigating the Effect of Column Geometry on Separation Efficiency using 3D Printed Liquid Chromatographic Columns Containing Polymer Monolithic Phases.

    Science.gov (United States)

    Gupta, Vipul; Beirne, Stephen; Nesterenko, Pavel N; Paull, Brett

    2018-01-16

    Effect of column geometry on the liquid chromatographic separations using 3D printed liquid chromatographic columns with in-column polymerized monoliths has been studied. Three different liquid chromatographic columns were designed and 3D printed in titanium as 2D serpentine, 3D spiral, and 3D serpentine columns, of equal length and i.d. Successful in-column thermal polymerization of mechanically stable poly(BuMA-co-EDMA) monoliths was achieved within each design without any significant structural differences between phases. Van Deemter plots indicated higher efficiencies for the 3D serpentine chromatographic columns with higher aspect ratio turns at higher linear velocities and smaller analysis times as compared to their counterpart columns with lower aspect ratio turns. Computational fluid dynamic simulations of a basic monolithic structure indicated 44%, 90%, 100%, and 118% higher flow through narrow channels in the curved monolithic configuration as compared to the straight monolithic configuration at linear velocities of 1, 2.5, 5, and 10 mm s -1 , respectively. Isocratic RPLC separations with the 3D serpentine column resulted in an average 23% and 245% (8 solutes) increase in the number of theoretical plates as compared to the 3D spiral and 2D serpentine columns, respectively. Gradient RPLC separations with the 3D serpentine column resulted in an average 15% and 82% (8 solutes) increase in the peak capacity as compared to the 3D spiral and 2D serpentine columns, respectively. Use of the 3D serpentine column at a higher flow rate, as compared to the 3D spiral column, provided a 58% reduction in the analysis time and 74% increase in the peak capacity for the isocratic separations of the small molecules and the gradient separations of proteins, respectively.

  13. Presence of Campylobacter and Salmonella in sand from bathing beaches.

    Science.gov (United States)

    Bolton, F J; Surman, S B; Martin, K; Wareing, D R; Humphrey, T J

    1999-02-01

    The purpose of this study was to determine the presence of thermophilic Campylobacter spp. and Salmonella spp. in sand from non-EEC standard and EEC standard designated beaches in different locations in the UK and to assess if potentially pathogenic strains were present. Campylobacter spp. were detected in 82/182 (45%) of sand samples and Salmonella spp. in 10/182 (6%). Campylobacter spp. were isolated from 46/92 (50%) of samples from non-EEC standard beaches and 36/90 (40%) from EEC standard beaches. The prevalence of Campylobacter spp. was greater in wet sand from both types of beaches but, surprisingly, more than 30% of samples from dry sand also contained these organisms. The major pathogenic species C. jejuni and C. coli were more prevalent in sand from non-EEC standard beaches. In contrast, C. lari and urease positive thermophilic campylobacters, which are associated with seagulls and other migratory birds, were more prevalent in sand from EEC standard beaches. Campylobacter isolates were further characterized by biotyping and serotyping, which confirmed that strains known to be of types associated with human infections were frequently found in sand on bathing beaches.

  14. Casting Ductile Iron in Layer Moulds Made from Ecological Sands

    Directory of Open Access Journals (Sweden)

    M. Rączka

    2012-09-01

    Full Text Available The article contains the results of tests performed under the target project in Hardtop Foundry Charsznica.The objective of the tests and studies was to develop a technology of making high-quality ductile iron castings, combined witheffective means of environmental protection. The studies presented in this article related to castings weighing from 1 to 300 kg made from ductile iron of grades 400-15 and 500-7, using two-layer moulds, where the facing and core sand was the sand with an alkaline organic binder, while backing sand was the sand with an inorganic geopolymer binder.A simplified method of sand reclamation was applied with possible reuse of the reclaim as an addition to the backing sand. The castiron spheroidising treatment and inoculation were selected taking into account the specific conditions of Hardtop Foundry. A pilot batch of castings was made, testing the gating and feeding systems and using exothermic sleeves on risers. The study confirmed the validity of the adopted concept of making ductile iron castings in layer moulds, while maintaining the content of sand with an organic binder at a level of maximum 15%.

  15. Preliminary fingerprinting analysis of Alberta oil sands and related petroleum products

    International Nuclear Information System (INIS)

    Yang, C.; Wang, Z.D.; Hollebone, B.; Brown, C.E.; Yang, Z.Y.; Landriault, M.; Fieldhouse, B.

    2009-01-01

    This paper reported on a study that presented a preliminary quantitative chemical characterization of Alberta oil sands and many other related Alberta oils such as oil sand bitumen, Cold Lake bitumen, Albian heavy synthetic crude, and Alberta Mixed sweet blend. The rapid increase in production of the Alberta oil sands has resulted in unprecedented environmental concern. The mining, extraction and production of oil sands such resulted in huge consumption of water resources, huge emission of greenhouse gas and large number of tailings ponds. In addition, accidental spills in the transportation and usage of oil sands will potentially cause considerable impact on the environment. It is therefore essential to have the ability to characterize Alberta oil sands and their oil products. The specific chemical properties of the oil sands bitumen must be known. Therefore, this study collected quantitative data on the concentration and distribution profiles of target compounds in Alberta oil sands and its petroleum products. The chemical fingerprints of 5 Alberta oil sands and their related petroleum products were studied using gas chromatography/flame ionization detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS). The characterized hydrocarbons were n-alkanes; target alkylated PAHs and other EPA priority PAHs; biomarker terpanes and steranes; and bicyclic sesquiterpanes. The information acquired during this study will provide the basis for oil-oil correlation and differentiation in future environmental applications relevant to oil sands. 24 refs., 6 tabs., 4 figs.

  16. Economic impacts of Alberta's oil sands, volume 1

    International Nuclear Information System (INIS)

    Timilsina, G.R.; LeBlanc, N.; Walden, T.

    2005-01-01

    In 2004, the international media recognized Alberta's oil sands as part of the global oil reserves, thereby establishing Canada as second to Saudi Arabia as potential oil producing nations. The economic impacts of Alberta's oil sands industry on economies were assessed at regional, provincial and international levels for the 2000 to 2020 period. A customized input-output model was used to assess economic impacts, which were measured in terms of changes in gross domestic product; employment and labour income; and, government revenues. Cumulative impacts on employment by sector and by jurisdiction were also presented. An investment of $100 billion is expected through 2020, resulting in production of crude bitumen and synthetic crude oil outputs valued at about $531 billion. The impact of the oil sands industry on local employment was also evaluated. It was shown that activities in the oil sands industry will lead to significant economic impact in Alberta, Ontario, Quebec and the rest of Canada. Alberta's local economy would be the main beneficiary of oil sands activities with nearly 3.6 million person years employment created in Alberta during the 2000 to 2020. Another 3 million person years employment would be created in other Canadian provinces and outside Canada during the same time period. A sensitivity analysis on the responsiveness to oil prices and the removal of various constraints incorporated in the main analysis was also presented. The federal government will be the largest recipient of revenues generated to to oil sands activities. The results of the study were compared with that of the National Task Force on Oil Sands Strategies. This first volume revealed the results of the study while the second volume includes the data and detailed results. 48 refs., 57 tabs., 28 figs

  17. Evaluation of Packed Distillation Columns I - Atmospheric Pressure

    National Research Council Canada - National Science Library

    Reynolds, Thaine

    1951-01-01

    .... Four column-packing combinations of the glass columns and four column-packing combinations of the steel columns were investigated at atmospheric pressure using a test mixture of methylcyclohexane...

  18. Center column design of the PLT

    International Nuclear Information System (INIS)

    Citrolo, J.; Frankenberg, J.

    1975-01-01

    The center column of the PLT machine is a secondary support member for the toroidal field coils. Its purpose is to decrease the bending moment at the nose of the coils. The center column design was to have been a stainless steel casting with the toroidal field coils grouped around the casting at installation, trapping it in place. However, the castings developed cracks during fabrication and were unsuitable for use. Installation of the coils proceeded without the center column. It then became necessary to redesign a center column which would be capable of installation with the toroidal field coils in place. The final design consists of three A-286 forgings. This paper discusses the final center column design and the influence that new knowledge, obtained during the power tests, had on the new design

  19. Phase behavior of methane hydrate in silica sand

    International Nuclear Information System (INIS)

    Sun, Shi-Cai; Liu, Chang-Ling; Ye, Yu-Guang; Liu, Yu-Feng

    2014-01-01

    Highlights: • Hydrate p-T trace in coarse-grained sediment is consistent with that in bulk water. • Fine-grained sediment affects hydrate equilibrium for the depressed water activity. • Hydrate equilibrium in sediment is related to the pore size distribution. • The application of hydrate equilibrium in sediment depends on the actual condition. -- Abstract: Two kinds of silica sand powder with different particle size were used to investigate the phase behavior of methane hydrate bearing sediment. In coarse-grained silica sand, the measured temperature and pressure range was (281.1 to 284.2) K and (5.9 to 7.8) MPa, respectively. In fine-grained silica sand, the measured temperature and pressure range was (281.5 to 289.5) K and (7.3 to 16.0) MPa, respectively. The results show that the effect of coarse-grained silica sand on methane hydrate phase equilibrium can be ignored; however, the effect of fine-grained silica sand on methane hydrate phase equilibrium is significant, which is attributed to the depression of water activity caused by the hydrophilicity and negatively charged characteristic of silica particle as well as the pore capillary pressure. Besides, the analysis of experimental results using the Gibbs–Thomson equation shows that methane hydrate phase equilibrium is related to the pore size distribution of silica sand. Consequently, for the correct application of phase equilibrium data of hydrate bearing sediment, the geological condition and engineering requirement should be taken into consideration in gas production, resource evaluation, etc

  20. Geophysical applications for oil sand mine tailings management

    Energy Technology Data Exchange (ETDEWEB)

    Parker, D.; Bauman, P. [WorleyParsons, Calgary, AB (Canada)

    2009-07-01

    Geophysical techniques are applied throughout a mine's life cycle to facilitate siting, constructing and monitoring of tailings dumps and ponds. This presentation described 3 case studies from the Athabasca region in northeast Alberta that demonstrated some of the concerns associated with oil sand mine tailings, and the information that geophysical surveys can provide. The objectives of these studies were to determine the lateral and depth extents of elevated conductivities of soil and groundwater that have high salt concentration from the tailings sand pore fluid. Due to high chloride concentrations within the tailings material, salt within the root zone may affect vegetation. A terrain conductivity survey was designed to map the lateral extents of salinity impact, while an electrical resistivity tomography (ERT) survey was used to delineate the tailings sand leachate at depth. The proper management of oil sand tailings facilities is vital to the life cycle of a mine. It was concluded that geophysical techniques can be instrumental in managing several engineering and environmental challenges, from Pleistocene channel mapping, to tailings pond settling characteristics, to reclaiming tailings sands. 1 ref., 7 figs.

  1. Dewatering Behaviour of Fine Oil Sands Tailings : An Experimental Study

    NARCIS (Netherlands)

    Yao, Y.

    2016-01-01

    Oil sands tailings are a warm aqueous suspension of sand, silt, clay, residual bitumen and naphtha. The tailings are hydraulically transported and stored in tailing ponds where they segregate, with the sand settling from suspension forming beaches and the remaining tailings flowing to the middle of

  2. Seasonal changing sand waves and the effect of surface waves

    NARCIS (Netherlands)

    Sterlini, Fenneke; van Dijk, Thaiënne A.G.P.; IJzer, Steven; Hulscher, Suzanne; Schüttrumpf, Holger; Tomasicchio, Guiseppe Roberto

    2012-01-01

    Sand waves are wavelike subaqueous sediment structures that exist in large areas in shelf seas. Due to their characteristics sand waves can severely affect human offshore activities, such as navigation. This makes it important to understand the physical processes that shape and change sand waves. In

  3. Acetylcholinesterase mutations and organophosphate resistance in sand flies and mosquitoes

    Science.gov (United States)

    Leishmaniasis is an insect-borne disease caused by several protozoan species in the genus Leishmania, which are vectored by sand fly species in the genera Phlebotomus or Lutzomyia, depending on the sand fly species geographic range. Sand fly bites and leishmaniasis significantly impacted U.S. milita...

  4. The handedness of historiated spiral columns.

    Science.gov (United States)

    Couzin, Robert

    2017-09-01

    Trajan's Column in Rome (AD 113) was the model for a modest number of other spiral columns decorated with figural, narrative imagery from antiquity to the present day. Most of these wind upwards to the right, often with a congruent spiral staircase within. A brief introductory consideration of antique screw direction in mechanical devices and fluted columns suggests that the former may have been affected by the handedness of designers and the latter by a preference for symmetry. However, for the historiated columns that are the main focus of this article, the determining factor was likely script direction. The manner in which this operated is considered, as well as competing mechanisms that might explain exceptions. A related phenomenon is the reversal of the spiral in a non-trivial number of reproductions of the antique columns, from Roman coinage to Renaissance and baroque drawings and engravings. Finally, the consistent inattention in academic literature to the spiral direction of historiated columns and the repeated publication of erroneous earlier reproductions warrants further consideration.

  5. Sand and Gravel Deposits

    Data.gov (United States)

    Vermont Center for Geographic Information — This dataset is a statewide polygon coverage of sand, gravel, and stone resources. This database includes the best data available from the VT Agency of Natural...

  6. Column-oriented database management systems

    OpenAIRE

    Možina, David

    2013-01-01

    In the following thesis I will present column-oriented database. Among other things, I will answer on a question why there is a need for a column-oriented database. In recent years there have been a lot of attention regarding a column-oriented database, even if the existence of a columnar database management systems dates back in the early seventies of the last century. I will compare both systems for a database management – a colum-oriented database system and a row-oriented database system ...

  7. High Temperature Thermal Properties of Bentonite Foundry Sand

    Directory of Open Access Journals (Sweden)

    Krajewski P.K.

    2015-06-01

    Full Text Available The paper presents results of measuring thermal conductivity and heat capacity of bentonite foundry sand in temperature range ambient - 900­­°C. During the experiments a technical purity Cu plate was cast into the green-sand moulds. Basing on measurements of the mould temperature field during the solidification of the casting, the temperature relationships of the measured properties were evaluated. It was confirmed that water vaporization strongly influences thermal conductivity of the moulding sand in the first period of the mould heating by the poured casting.

  8. Dark grains of sand: a geological storytelling

    Science.gov (United States)

    Gallo Maresca, Magda

    2017-04-01

    In the secondary Italian school the Earth science learning begins at first year, in synergy with other natural science subjects such as Astronomy, Chemistry and Biology. Italian teachers have to focus on the landscape geomorphological aspects and often Earth processes are difficult to display since they are related to certain phenomena happened during the past and often far from the involved country. In order to better understand the environment surrounding us, very simple and poor materials, like sands, allow the teachers to create attractive lab experiences. According to the IBSE (Inquiry Based Science Education) approach, a learning unit has been implemented starting from a walking along the light carbonate beaches of the Adriatic sea: a smart look to the sands ("engage step"), stroke the students fantasy pushing them to explore some strange black grains on the sands. Dirty sands? Or rock landscape, soil degradation and Ofanto river and coastal processes (erosion, transportation and deposition)? This was the teaching challenge. Due to the youngest age, a third level, guided inquiry, was adopted so the teacher is the "guide of inquiry" encouraging the students using the research question ("Why is the sand dark?", "Do all sands look the same?", "Where does it come from?") and driving the students around their investigation plans ("How can I measure grain size?"). A procedure to answer the above questions and validate the results and explanations has been implemented to allow the students to be proactive in their study. During the learning activities will be the students to ask for field trip to elaborate their new knowledge, verify and visualize the speculated processes. The teaching skills allow to address several geosciences domains such as mineralogy, petrology, regional geology and geodynamics as well as other scientific disciplines such as mathematics (more specifically statistics), forensic science and even life sciences (the presence of bioclasts might

  9. Assessing environmental impacts of inland sand mining in parts of ...

    African Journals Online (AJOL)

    Sand is a valuable resource for construction and other purposes, however sand mining often result in serious environmental problems such as land degradation, loss of agricultural lands and biodiversity, as well increased poverty among people. This study assessed the environmental impacts of inland sand mining in six ...

  10. Efficiency of Micro-fine Cement Grouting in Liquefiable Sand

    International Nuclear Information System (INIS)

    Mirjalili, Mojtaba; Mirdamadi, Alireza; Ahmadi, Alireza

    2008-01-01

    In the presence of strong ground motion, liquefaction hazards are likely to occur in saturated cohesion-less soils. The risk of liquefaction and subsequent deformation can be reduced by various ground improvement methods including the cement grouting technique. The grouting method was proposed for non-disruptive mitigation of liquefaction risk at developed sites susceptible to liquefaction. In this research, a large-scale experiment was developed for assessment of micro-fine cement grouting effect on strength behavior and liquefaction potential of loose sand. Loose sand samples treated with micro-fine grout in multidirectional experimental model, were tested under cyclic and monotonic triaxial loading to investigate the influence of micro-fine grout on the deformation properties and pore pressure response. The behavior of pure sand was compared with the behavior of sand grouted with a micro-fine cement grout. The test results were shown that cement grouting with low concentrations significantly decreased the liquefaction potential of loose sand and related ground deformation

  11. Radiotracer Imaging of Sediment Columns

    Science.gov (United States)

    Moses, W. W.; O'Neil, J. P.; Boutchko, R.; Nico, P. S.; Druhan, J. L.; Vandehey, N. T.

    2010-12-01

    Nuclear medical PET and SPECT cameras routinely image radioactivity concentration of gamma ray emitting isotopes (PET - 511 keV; SPECT - 75-300 keV). We have used nuclear medical imaging technology to study contaminant transport in sediment columns. Specifically, we use Tc-99m (T1/2 = 6 h, Eγ = 140 keV) and a SPECT camera to image the bacteria mediated reduction of pertechnetate, [Tc(VII)O4]- + Fe(II) → Tc(IV)O2 + Fe(III). A 45 mL bolus of Tc-99m (32 mCi) labeled sodium pertechnetate was infused into a column (35cm x 10cm Ø) containing uranium-contaminated subsurface sediment from the Rifle, CO site. A flow rate of 1.25 ml/min of artificial groundwater was maintained in the column. Using a GE Millennium VG camera, we imaged the column for 12 hours, acquiring 44 frames. As the microbes in the sediment were inactive, we expected most of the iron to be Fe(III). The images were consistent with this hypothesis, and the Tc-99m pertechnetate acted like a conservative tracer. Virtually no binding of the Tc-99m was observed, and while the bolus of activity propagated fairly uniformly through the column, some inhomogeneity attributed to sediment packing was observed. We expect that after augmentation by acetate, the bacteria will metabolically reduce Fe(III) to Fe(II), leading to significant Tc-99m binding. Imaging sediment columns using nuclear medicine techniques has many attractive features. Trace quantities of the radiolabeled compounds are used (micro- to nano- molar) and the half-lives of many of these tracers are short (Image of Tc-99m distribution in a column containing Rifle sediment at four times.

  12. Sustainable water management in Alberta's oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Byers, Bill; Usher, Robyn; Roach, Andrea [CH2M HILL, Englewood, CO (United States); Lambert, Gord; Kotecha, Prit [Suncor Energy Inc., Calgary (Canada)

    2012-07-01

    The Canadian Association of Petroleum Producers forecast published in 2011 predicts that oil production from oil sands will increase by 50% in the next 3 years and double by 2020. This rate of growth will result in significant pressure on water resources; water use per barrel of oil sands production is comparable to other energy resources - about 2.5 barrels of fresh water per barrel of oil produced are used by mining operations and 0.5 barrels by in-situ operations. Suncor Energy Inc. (Suncor) was the first company to develop the oil sands in northern Alberta and holds one of the largest oil sands positions in Canada. In 2010, Suncor announced plans to increase production to more than 1 million barrels of oil equivalent per day by 2020, which it plans to achieve through oil sands production growth of approximately 10% per year. Because water supply and potential impacts to water quality are critical to its future growth, in 2010-2011 Suncor conducted a risk assessment to identify water-related business risks related to its northern Alberta operations. The assessment identified more than 20 high level business risks in strategic water risk areas including water supply, water reuse, storm water management, groundwater, waste management and river water return. The risk assessment results prompted development of a strategic roadmap to guide water stewardship across Suncor's regional operations. The roadmap describes goals, objectives, and specific activities for each of six key water risk areas, and informs prioritization and selection of prospective water management activities. Suncor is not only exploring water within its own boundaries, but is also collaborating with other oil sands producers to explore ways of integrating its water systems through industry consortia; Suncor is a member of the Oil Sands Leadership Initiative and of the recently formed Canadian Oil Sands Innovation Alliance, among others. (author)

  13. Phase-Space Models of Solitary Electron Hoies

    DEFF Research Database (Denmark)

    Lynov, Jens-Peter; Michelsen, Poul; Pécseli, Hans

    1985-01-01

    Two different phase-space models of solitary electron holes are investigated and compared with results from computer simulations of an actual laboratory experiment, carried out in a strongly magnetized, cylindrical plasma column. In the two models, the velocity distribution of the electrons...

  14. Thermally stable dexsil-400 glass capillary columns

    International Nuclear Information System (INIS)

    Maskarinec, M.P.; Olerich, G.

    1980-01-01

    The factors affecting efficiency, thermal stability, and reproducibility of Dexsil-400 glass capillary columns for gas chromatography in general, and for polycyclic aromatic hydrocarbons (PAHs) in particular were investigated. Columns were drawn from Kimble KG-6 (soda-lime) glass or Kimox (borosilicate) glass. All silylation was carried out at 200 0 C. Columns were coated according to the static method. Freshly prepared, degassed solutions of Dexsil-400 in pentane or methylene chloride were used. Thermal stability of the Dexsil 400 columns with respect to gas chromatography/mass spectrometry (GC/MS) were tested. Column-to-column variability is a function of each step in the fabrication of the columns. The degree of etching, extent of silylation, and stationary phase film thickness must be carefully controlled. The variability in two Dexsil-400 capillary column prepared by etching, silylation with solution of hexa methyl disilazone (HMDS), and static coating is shown and also indicates the excellent selectivity of Dexsil-400 for the separation of alkylated aromatic compounds. The wide temperature range of Dexsil-400 and the high efficiency of the capillary columns also allow the analysis of complex mixtures with minimal prefractionation. Direct injection of a coal liquefaction product is given. Analysis by GC/MS indicated the presence of parent PAHs, alkylated PAHs, nitrogen and sulfur heterocycles, and their alkylated derivatives. 4 figures

  15. Determination of the hydraulic conductivity in column of undeformed soil by gamma rays transmission

    International Nuclear Information System (INIS)

    Moreira, Anderson C.; Cavalcante, Fabio H.M.; Portezan Filho, Otavio; Coimbra, Melayne M.; Appoloni, Carlos Roberto

    2000-01-01

    The water infiltration process in undeformed soil column and the measurement of redistribution process by gamma rays transmission in different depth allow the determination of Hydraulic Conductivity K(Θ) function, using the Sisson et al. (1980) method. A LRd (dystrophic dark red soil) soil column with 60 cm of height, 10 cm of width and 5 cm of thickness, was analyzed in laboratory, reproducing the field conditions concerning to the water infiltration and redistribution in the soil. The soil moisture content data was obtained with a radioactivity source 241 Am (100 mCi; 59,6 keV), NaI (Tl) 2x2 detector, coupled to an gamma rays spectrometric electronic chain and a measurement table that allowed the vertical displacement of the soil column. The results indicate a growing behavior for K(Θ) in relation to the depth. The collimators had 2 mm and 5 mm diameter for radioactivity source and detector respectively. (author)

  16. Design and Fabrication of a Foundry Sand Mixer Using Locally ...

    African Journals Online (AJOL)

    Most small foundry shops mix their sand manually which is not efficient since homogenous mix cannot be guaranteed and even when foundry mixer are available most of them are imported costing the nation huge foriegn exchange. A foundry sand mixer capable of mixing foundry sand has been designed and fabricated ...

  17. Mites and spiders act as biological control agent to sand flies

    Directory of Open Access Journals (Sweden)

    Diwakar Singh Dinesh

    2014-02-01

    Full Text Available Objective: To find out natural biological control agents of sand flies vector of kala azar in Bihar, India. Methods: Sand flies collected from the field using CDC light trap installing overnight to the collection site scrutitinized for Phlebotomus argentipes, the established vector of visceral leishmaniasis. Blood fed adult females were confined in the insectary for its development of life cycle. During developmental stages 2nd to 4th instars larvae were examined closely by using compound microscope for mite infestation. Adult spider residing along with sand flies collected in trap were kept in cage along with sand flies and their activities were watched closely and recorded by video and picture. Results: Mites were found predating 2nd to 4th instars larvae only under the laboratory conditions and lowering down the population of sand flies up to basal level within 15 d after infestation. One specific spider was found eating blood fed female sand flies kept inside the cage (n=50 attacking on lower part of thoracic region to kill the sand fly and ate desired soft part. Conclusions: Both predators, mites and spiders are acting as biological control agents to larvae and adults of sand flies respectively resulting variable density of vectors due to variable association with these predators and also cause lowering the transmission of the disease as hidden natural controlling agent of sand flies. The extensive study will be of immense help in controlling sand flies without use of environmental pollutant i.e. chemical insecticide.

  18. Continuous-flow column study of reductive dehalogenation of PCE upon bioaugmentation with the Evanite enrichment culture

    Science.gov (United States)

    Azizian, Mohammad F.; Behrens, Sebastian; Sabalowsky, Andrew; Dolan, Mark E.; Spormann, Alfred M.; Semprini, Lewis

    2008-08-01

    A continuous-flow anaerobic column experiment was conducted to evaluate the reductive dechlorination of tetrachloroethene (PCE) in Hanford aquifer material after bioaugmentation with the Evanite (EV) culture. An influent PCE concentration of 0.09 mM was transformed to vinyl chloride (VC) and ethene (ETH) within a hydraulic residence time of 1.3 days. The experimental breakthrough curves were described by the one-dimensional two-site-nonequilibrium transport model. PCE dechlorination was observed after bioaugmentation and after the lactate concentration was increased from 0.35 to 0.67 mM. At the onset of reductive dehalogenation, cis-dichloroethene (c-DCE) concentrations in the column effluent exceeded the influent PCE concentration indicating enhanced PCE desorption and transformation. When the lactate concentration was increased to 1.34 mM, c-DCE reduction to vinyl chloride (VC) and ethene (ETH) occurred. Spatial rates of PCE and VC transformation were determined in batch-incubated microcosms constructed with aquifer samples obtained from the column. PCE transformation rates were highest in the first 5 cm from the column inlet and decreased towards the column effluent. Dehalococcoides cell numbers dropped from ˜ 73.5% of the total Bacterial population in the original inocula, to about 0.5% to 4% throughout the column. The results were consistent with estimates of electron donor utilization, with 4% going towards dehalogenation reactions.

  19. Degradation of pollutants and elimination of pathogens of waste water by adsorption of accelerated electrons; Degradacion de contaminantes y eliminacion de patogenos de aguas residuales por adsorcion de electrones acelerados

    Energy Technology Data Exchange (ETDEWEB)

    Martinez M, I

    1991-10-15

    This report presents a position of the pollutants degradation of the industrial residual waters, it intends a method that consists on making pass residual water, treated biologically by a packed column with activated carbon. The carbon retains the pollutants and the water goes out with a purity that allows the reuse. In simultaneous form to the adsorption of pollutants are made pass electrons through the column of carbon, the electrons will destroy to the polluting adsorbed in the carbon; the pollutants degrade until CO{sub 2} that escapes as gas. The active sites of the carbon are empty and clever to be occupied by other pollutants. This process is continuous and it is repeated while water is passing by the column and electrons through this. (Author)

  20. Alberta Oil Sands Equity annual report, 1992-93. Partnership and progress in Alberta's oil sands development

    International Nuclear Information System (INIS)

    1993-01-01

    Alberta Oil Sands Equity (AOSE) manages the Alberta government's equity investments in oil sands and heavy oil projects. AOSE is a 16.74% participant in the Syncrude Project, a 10% participant in the OSLO (Other Six Leases Operation) Commercial Project and the OSLO New Ventures project, and a 24.17% participant in the Lloydminster Bi-Provincial Upgrader. Syncrude produces ca 12% of Canadian crude oil requirements, and AOSE's share yielded $44 million profit for 1992/93, slightly higher than the the $43.3 million the previous year. The OSLO Commercial Project is a proposed commercial oil sands plant with a mine site and extraction plant to be located north of Fort McMurray, and an upgrading facility to be situated north of Edmonton. Work on this project was suspended in early 1992. The OSLO New Ventures project will handle the exploration and development of the remaining five oil sands leases plus the southern portion of Lease 31. As of March 31, 1993, the project owners were considering a commercial demonstration project utilizing dredging and cold-water extraction processes. Two of the owners are unable to provide funding and discussions are under way to resolve the matter and move the program forward. The Lloydminster Bi-Provincial Upgrader opened Noveber 20, 1992, and production has reached 41,000 bbl/d, or 89% of design capacity. The upgrader will increase the value of heavy crude oil and thereby increase its demand. 5 figs., 3 tabs

  1. An investigation of waste foundry sand in asphalt concrete mixtures.

    Science.gov (United States)

    Bakis, Recep; Koyuncu, Hakan; Demirbas, Ayhan

    2006-06-01

    A laboratory study regarding the reuse of waste foundry sand in asphalt concrete production by replacing a certain portion of aggregate with WFS was undertaken. The results showed that replacement of 10% aggregates with waste foundry sand was found to be the most suitable for asphalt concrete mixtures. Furthermore, the chemical and physical properties of waste foundry sand were analysed in the laboratory to determine the potential effect on the environment. The results indicated that the investigated waste foundry sand did not significantly affect the environment around the deposition

  2. Safety barriers and lighting columns.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1972-01-01

    Problems arising from the sitting of lighting columns on the central reserve are reviewed, and remedial measures such as break-away lighting supports and installation of safety fences on the central reserve on both sides of the lighting columns are examined.

  3. Design of Screens for Sand Control of Wells

    Directory of Open Access Journals (Sweden)

    Ján Pinka

    2006-04-01

    Full Text Available Drilling, completion, production, and reservoir engineers, supervisors, foremen, superintendents, service company personnel, technologists and anyone involved with recommending, selecting, designing or on-site performance of well completions or workovers where sand production is, or may become, a serious problem will benefit from this course. Less sand influx can be expected in a horizontal well than in a vertical well. If horizontal holes in weak formation sands can be successfully gravel packed, the result could be significantly higher well productivity than with a liner, screen or pre-packed screen alone. The article covers innovative screens for sand control used in oil and gas industry from the world leaders in total completion. The type of screen (wire wrapped, reinforced, pre-packed, ect. should also be chosen with due consideration to running-in condition (curve radius, compression when the screens are pushed along the drain hole, etc..

  4. Temperature-assisted On-column Solute Focusing: A General Method to Reduce Pre-column Dispersion in Capillary High Performance Liquid Chromatography

    Science.gov (United States)

    Groskreutz, Stephen R.; Weber, Stephen G.

    2014-01-01

    Solvent-based on-column focusing is a powerful and well known approach for reducingthe impact of pre-column dispersion in liquid chromatography. Here we describe an orthogonal temperature-based approach to focusing called temperature-assisted on-column solute focusing (TASF). TASF is founded on the same principles as the more commonly used solvent-based method wherein transient conditions are created thatlead to high solute retention at the column inlet. Combining the low thermal mass of capillary columns and the temperature dependence of solute retentionTASF is used effectivelyto compress injection bands at the head of the column through the transient reduction in column temperature to 5 °C for a defined 7 mm segment of a 6 cm long 150 μm I.D. column. Following the 30 second focusing time, the column temperature is increased rapidly to the separation temperature of 60 °C releasing the focused band of analytes. We developed a model tosimulate TASF separations based on solute retention enthalpies, focusing temperature, focusing time, and column parameters. This model guides the systematic study of the influence of sample injection volume on column performance.All samples have solvent compositions matching the mobile phase. Over the 45 to 1050 nL injection volume range evaluated, TASF reducesthe peak width for all soluteswith k’ greater than or equal to 2.5, relative to controls. Peak widths resulting from injection volumes up to 1.3 times the column fluid volume with TASF are less than 5% larger than peak widths from a 45 nL injection without TASF (0.07 times the column liquid volume). The TASF approach reduced concentration detection limits by a factor of 12.5 relative to a small volume injection for low concentration samples. TASF is orthogonal to the solvent focusing method. Thus, it canbe used where on-column focusing is required, but where implementation of solvent-based focusing is difficult. PMID:24973805

  5. The stable stiffness triangle - drained sand during deformation cycles

    DEFF Research Database (Denmark)

    Sabaliauskas, Tomas; Ibsen, Lars Bo

    2017-01-01

    Cyclic, drained sand stiffness was observed using the Danish triaxial appa- ratus. New, deformation dependant soil property (the stable stiffness triangle) was detected. Using the the stable stiffness triangle, secant stiffness of drained sand was plausible to predict (and control) even during ir...... findings can find application in off-shore, seismic and other engi- neering practice, or inspire new branches of research and modelling wherever dynamic, cyclic or transient loaded sand is encountered....

  6. White Sands, New Mexico as seen from STS-60

    Science.gov (United States)

    1994-01-01

    White Sands National Monument (Park) is easily recognized in the center of this near-vertical color photograph. White Sands is the world's largest gypsum dune field. It represents an alabaster sea that covers nearly 300 square miles. At the southwest corner of the White Sands is dry lake, Lucero. In terms of cultural features the city of Alamogordo and Holloman Air Force Base can be seen with great clarity on this photograph.

  7. Design of dry sand soil stratified sampler

    Science.gov (United States)

    Li, Erkang; Chen, Wei; Feng, Xiao; Liao, Hongbo; Liang, Xiaodong

    2018-04-01

    This paper presents a design of a stratified sampler for dry sand soil, which can be used for stratified sampling of loose sand under certain conditions. Our group designed the mechanical structure of a portable, single - person, dry sandy soil stratified sampler. We have set up a mathematical model for the sampler. It lays the foundation for further development of design research.

  8. Heat Transfer Analysis for a Fixed CST Column

    International Nuclear Information System (INIS)

    Lee, S.Y.

    2004-01-01

    In support of a small column ion exchange (SCIX) process for the Savannah River Site waste processing program, a transient two-dimensional heat transfer model that includes the conduction process neglecting the convection cooling mechanism inside the crystalline silicotitanate (CST) column has been constructed and heat transfer calculations made for the present design configurations. For this situation, a no process flow condition through the column was assumed as one of the reference conditions for the simulation of a loss-of-flow accident. A series of the modeling calculations has been performed using a computational heat transfer approach. Results for the baseline model indicate that transit times to reach 130 degrees Celsius maximum temperature of the CST-salt solution column are about 96 hours when the 20-in CST column with 300 Ci/liter heat generation source and 25 degrees Celsius initial column temperature is cooled by natural convection of external air as a primary heat transfer mechanism. The modeling results for the 28-in column equipped with water jacket systems on the external wall surface of the column and water coolant pipe at the center of the CST column demonstrate that the column loaded with 300 Ci/liter heat source can be maintained non-boiling indefinitely. Sensitivity calculations for several alternate column sizes, heat loads of the packed column, engineered cooling systems, and various ambient conditions at the exterior wall of the column have been performed under the reference conditions of the CST-salt solution to assess the impact of those parameters on the peak temperatures of the packed column for a given transient time. The results indicate that a water-coolant pipe at the center of the CST column filled with salt solution is the most effective one among the potential design parameters related to the thermal energy dissipation of decay heat load. It is noted that the cooling mechanism at the wall boundary of the column has significant

  9. NON-LINEAR ANALYSIS OF AN EXPERIMENTAL JOINT OF COLUMN AND BEAMS OF ARMED CONCRETE-STEEL COLUMN FOR FRAME

    Directory of Open Access Journals (Sweden)

    Nelson López

    2017-12-01

    Full Text Available In this research, the nonlinear behavior of a real-scale experimental joint (node is studied, consisting of three reinforced concrete elements, one column and two beams joined to a structural steel column at the upper level. In the numerical analysis the model of the union was analyzed in the inelastic range, this model was elaborated with the finite element program based on fibers, SeismoStruct to analyze as a function of time, the traction and compression efforts in the confined area and not confined area of the concrete column and in the longitudinal reinforcement steel, as well as verification of the design of the base plate that joins the two columns. The results showed that tensile stresses in the unconfined zone surpassed the concrete breaking point, with cracking occurring just below the lower edge of the beams; in the confined area the traction efforts were much lower, with cracks occurring later than in the non-confined area. The concrete column-steel column joint behaved as a rigid node, so the elastic design was consistent with the calculation methodology of base plates for steel columns.

  10. Study of glow discharge positive column with cloud of disperse particles

    International Nuclear Information System (INIS)

    Polyakov, D.N.; Shumova, V.V.; Vasilyak, L.M.; Fortov, V.E.

    2011-01-01

    The study aims to describe plasma parameters changes induced by clouds of disperse micron size particles. Dust clouds were formed in the positive column of glow discharge in air at pressure 0.1-0.6 torr and current 0.1-3 mA. The simultaneous registration of discharge voltage and dust cloud parameters was carried out. Experimental results were simulated using diffusion model. The dust cloud is shown to smooth the radial electron concentration profile, increase electric field strength and electron temperature and stabilize the discharge. The cloud is demonstrated to be a trap for positive ions without increase of discharge current. -- Highlights: → 25% increase of longitudinal electric field strength in discharge with dust cloud. → The smoothing effect of dust cloud on radial electron and ion concentration profiles. → Dust cloud as a trap for positive ions without increase of discharge current. → Increase of electron temperature in discharge with dust cloud. → Increase of discharge stability in presence of dust cloud.

  11. Log-inject-log in sand consolidation

    International Nuclear Information System (INIS)

    Murphy, R.P.; Spurlock, J.W.

    1977-01-01

    A method is described for gathering information for the determination of the adequacy of placement of sand consolidating plastic for sand control in oil and gas wells. The method uses a high neutron cross-section tracer which becomes part of the plastic and uses pulsed neutron logging before and after injection of the plastic. Preferably, the method uses lithium, boron, indium, and/or cadmium tracers. Boron oxide is especially useful and can be dissolved in alcohol and mixed with the plastic ingredients

  12. Re-usage of waste foundry sand in high-strength concrete.

    Science.gov (United States)

    Guney, Yucel; Sari, Yasin Dursun; Yalcin, Muhsin; Tuncan, Ahmet; Donmez, Senayi

    2010-01-01

    In this study, the potential re-use of waste foundry sand in high-strength concrete production was investigated. The natural fine sand is replaced with waste foundry sand (0%, 5%, 10%, and 15%). The findings from a series of test program has shown reduction in compressive and tensile strengths, and the elasticity modulus which is directly related to waste foundry inclusion in concrete. Nevertheless the concrete with 10% waste foundry sand exhibits almost similar results to that of the control one. The slump and the workability of the fresh concrete decreases with the increase of the waste foundry sand ratio. Although the freezing and thawing significantly reduces the mechanical and physical properties of the concrete. The obtained results satisfies the acceptable limits set by the American Concrete Institute (ACI). 2010 Elsevier Ltd. All rights reserved.

  13. Fabrication of a micrometer Ni–Cu alloy column coupled with a Cu micro-column for thermal measurement

    International Nuclear Information System (INIS)

    Lin, J C; Chang, T K; Yang, J H; Jeng, J H; Lee, D L; Jiang, S B

    2009-01-01

    Micrometer Ni–Cu alloy columns have been fabricated by the micro-anode-guided electroplating (MAGE) process in the citrate bath. The surface morphology and chemical composition of the micro-columns were determined by copper concentration in the bath and by the electrical bias of MAGE. When fabricated in a bath of dilute copper (i.e. 4 mM) at lower voltages (e.g. 3.8 and 4.0 V), the alloy micro-columns revealed uniform diameter and smooth appearance. The alloy composition demonstrated an increase in the wt% ratio of Ni/Cu from 75/25, 80/20, 83/17 to 87/13 with increasing electrical bias from 3.8, 4.0, 4.2 to 4.4 V. However, it decreases from 75/25, 57/43 to 47/53 with increasing copper concentration from 4, 8 to 12 mM in the bath. Citrate plays a role in forming complexes with nickel and copper at similar reduction potentials, thus reducing simultaneously to Ni–Cu alloy. The mechanism for fabricating alloy micro-columns could be delineated on the basis of cathodic polarization of the complexes. A couple of micro-columns were fabricated using MAGE in constructing a pure copper micro-column on the top of a Ni/Cu (at 47/53) alloy micro-column. This micro-thermocouple provides a satisfactory measurement with good sensitivity and precision

  14. Study on strength characteristics of concrete using M-Sand and coconut fibers

    Science.gov (United States)

    Neeraja, D.; Wani, Amir Iqbal; Kamili, Zainulabideen; Agarwal, Krishnakant

    2017-11-01

    In the current world, concrete has become a very important part of the construction industry and the materials which are used in making concrete have evolved due to better quality of cement and better grade of coarse aggregates. The sand is an important part of concrete. It is mainly procured from natural sources. Thus the grade of sand is not under our control. The methods of removing sand from river beds are causing various environmental issues and river sand is depleting at a faster rate than it is replaced by natural methods. Hence, various replacements for the river sand are being done, one of which is manufactured-sand. It is obtained from various granite quarries. Manufactured-sand or M-sand is slowly replacing the fine aggregate in the concrete as the sand is well graded and gives higher strength of concrete. There are various fibers used for reinforcing concrete which consist mainly of artificial or steel fibers. Some of these fibers are quite costly and sometimes difficult to obtain. So there are many natural fibers which can be used in place of these fibers, one of which is coconut fiber, extracted from the shell of a coconut. Coconut fibers are used in various industries like rope making, coir mattresses etc. Since these fibers are one of the strongest fibers among naturally occuring fibers, they can be used in the concrete mix to increase the resistance in concrete. They are also light weight and easily available and thus can be used in reinforcement of concrete. The studies up till now have tested the use of coconut fibers in normal concrete involving river sand but in this study a particular ratio of M-sand and river sand is used to get the maximum possible strength. Hence, in this project an attempt was made to use M-sand and coconut fiber in concrete. Based on the test results, it can be concluded that combination of M-sand and coconut fibers gave favorable results in strength criteria.

  15. Sand transport in urbanized beaches - models and reality

    International Nuclear Information System (INIS)

    Pineiro, G.; Norbis, W.; Panario, D.

    2012-01-01

    The general objective is to quantify the wind transport of sand in the urbanized beaches. The specific objectives include testing and calibration of the wind velocity as well as the classification of the beaches according to the magnitude and the direction of sand transport

  16. Long-term flow rates and biomat zone hydrology in soil columns receiving septic tank effluent.

    Science.gov (United States)

    Beal, C D; Gardner, E A; Kirchhof, G; Menzies, N W

    2006-07-01

    Soil absorption systems (SAS) are used commonly to treat and disperse septic tank effluent (STE). SAS can hydraulically fail as a result of the low permeable biomat zone that develops on the infiltrative surface. The objectives of this experiment were to compare the hydraulic properties of biomats grown in soils of different textures, to investigate the long-term acceptance rates (LTAR) from prolonged application of STE, and to assess if soils were of major importance in determining LTAR. The STE was applied to repacked sand, Oxisol and Vertisol soil columns over a period of 16 months, at equivalent hydraulic loading rates of 50, 35 and 8L/m(2)/d, respectively. Infiltration rates, soil matric potentials, and biomat hydraulic properties were measured either directly from the soil columns or calculated using established soil physics theory. Biomats 1 to 2 cm thick developed in all soils columns with hydraulic resistances of 27 to 39 d. These biomats reduced a 4 order of magnitude variation in saturated hydraulic conductivity (K(s)) between the soils to a one order of magnitude variation in LTAR. A relationship between biomat resistance and organic loading rate was observed in all soils. Saturated hydraulic conductivity influenced the rate and extent of biomat development. However, once the biomat was established, the LTAR was governed by the resistance of the biomat and the sub-biomat soil unsaturated flow regime induced by the biomat. Results show that whilst initial soil K(s) is likely to be important in the establishment of the biomat zone in a trench, LTAR is determined by the biomat resistance and the unsaturated soil hydraulic conductivity, not the K(s) of a soil. The results call into question the commonly used approach of basing the LTAR, and ultimately trench length in SAS, on the initial K(s) of soils.

  17. Geophysics comes of age in oil sands development

    Energy Technology Data Exchange (ETDEWEB)

    Bauman, P. [WorleyParsons Komex, Calgary, AB (Canada); Birch, R.; Parker, D.; Andrews, B. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics

    2008-07-01

    This paper discussed geophysical techniques developed for oil sands exploration and production applications in Alberta's oil sands region. Geophysical methods are playing an important role in mine planning, tailings containment, water supply, and land reclamation activities. Geophysics techniques are used to estimate the volume of muskeg that needs to be stripped and stored for future reclamation activities as well as to site muskeg piles and delineate the thickness of clay Clearwater formations overlying Cretaceous oil-bearing sands. 2-D electrical resistivity mapping is used to map river-connected deep bedrock Pleistocene paleovalleys in the region. Geophysical studies are also used to investigate the interiors of dikes and berms as well as to monitor salt migration within tailings piles. Sonic and density logs are used to create synthetic seismograms for mapping the Devonian surface in the region. The new applications included the calculation of bitumen saturation from surface sands and shales; muskeg thickness mapping; and non-intrusive monitoring of leachate plumes. Geophysical techniques included 2-D electrical resistivity imaging; transient electromagnetic (EM) technologies; ground penetrating radar; and high-resolution seismic reflections. Polarization, surface nuclear magnetic resonance and push-probe sensing techniques were also discussed. Techniques were discussed in relation to Alberta's Athabasca oil sands deposits. 4 refs.

  18. Seismic stochastic inversion identify river channel sand body

    Science.gov (United States)

    He, Z.

    2015-12-01

    The technology of seismic inversion is regarded as one of the most important part of geophysics. By using the technology of seismic inversion and the theory of stochastic simulation, the concept of seismic stochastic inversion is proposed.Seismic stochastic inversion can play an significant role in the identifying river channel sand body. Accurate sand body description is a crucial parameter to measure oilfield development and oilfield stimulation during the middle and later periods. Besides, rational well spacing density is an essential condition for efficient production. Based on the geological knowledge of a certain oilfield, in line with the use of seismic stochastic inversion, the river channel sand body in the work area is identified. In this paper, firstly, the single river channel body from the composite river channel body is subdivided. Secondly, the distribution of river channel body is ascertained in order to ascertain the direction of rivers. Morever, the superimposed relationship among the sand body is analyzed, especially among the inter-well sand body. The last but not at the least, via the analysis of inversion results of first vacuating the wells and continuous infilling later, it is meeted the most needs well spacing density that can obtain the optimal inversion result. It would serve effective guidance for oilfield stimulation.

  19. Planning for, and measuring, the business value of technology projects in the oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Sayed, M. [Northern Alberta Inst. of Technology, Edmonton, AB (Canada); Burgess, A. [Telus Energy Sector Organization, Calgary, AB (Canada)

    2007-07-01

    This presentation discussed new communications technology options developed for oil sands industry operators. Technology options included broadband access for data, video and voice requirements, as well as new options for video, audio, and web conferencing. Recent technology options for inter-camp communications were presented, as well as new software developments for distance education, video surveillance, and data security. Various entertainment technologies for oil sands camp employees included in-room telephones, internet and gaming access, radio, television, and family web-cams. New electronic permitting equipment was described, and details of security and verification cards and tickets were provided. The economic benefits and social advantages of adopting the technologies were discussed. A research project and assessment tool designed to predict and measure the business value of information technology (IT) and communications technologies and projects was outlined. A case study of the Schlumberger heavy equipment program was used to demonstrate the assessment tool. refs., tabs., figs.

  20. Effect of River Indus Sand on Concrete Tensile Strength

    Directory of Open Access Journals (Sweden)

    M. T. Lakhiar

    2018-04-01

    Full Text Available In the development of Pakistan construction industry, the utilization of River Indus sand in concrete as fine aggregate has expanded tremendously. The aim of this research is to study the effect of Indus River sand on the tensile strength of various grades of concrete when it is utilized as fine aggregate. Concrete Samples of M15, M20 and M25 grade concrete were cured for 7, 14, 21 and 28 days. Based on the results, it is found that concrete became less workable when Indus river sand was utilized. It is recorded that tensile strength of concrete is decreased from 5% up to 20% in comparison with hill sand. The results were derived from various concrete grades.

  1. Microbial-Induced Heterogeneity in the Acoustic Properties of Porous Media

    Science.gov (United States)

    Acoustic wave data were acquired over a two-dimensional region of a microbial-stimulated sand column and an unstimulated sand column to assess the spatiotemporal changes in a porous medium caused by microbial growth and biofilm formation. The acoustic signals from the unstimulate...

  2. LAND COVER DYNAMICS OF OLESHKY SANDS: TIME-SERIES ANALYSIS 1987-2017

    Directory of Open Access Journals (Sweden)

    V. Bogdanets

    2017-11-01

    Full Text Available Oleshky Sands is the largest expanse of sand in Ukraine and the second in Europe. In the beginning of XX century sands moving outside of arenas was almost stopped by planting trees (Pinus nigra ssp. pallasian and Pinus sylvestris L., and the territory had different use during the years. A 30-year (1987-2017 time series of Landsat imagery obtained via USGS geoservice was used to reveal land cover dynamics of deserted landscapes of Oleshky sands using QGIS software. Heavy sand storms can impact nearby settlements and expose harmful effect on local industry and quality of life of local communities. Forest fire is another dangerous factor for protective forest plantations during last years. Our estimation shows that sandy areas increase during 2000-2017; generally, conservation measures had constant effect despite afforestation of last years. The preventive effect of forest on sands moving at Oleshky sands can be characterized as stable in case of constant care about the forest plantation and proper documentation on land use and ownership.

  3. Beach Sand Analysis for Indicators of Microbial Contamination

    Science.gov (United States)

    Traditional beach monitoring has focused on water quality, with little attention paid to health risks associated with beach sand. Recent research has reported that fecal indicator bacteria, as well as human pathogens can be found in beach sand and may constitute a risk to human h...

  4. Behavior of reinforced concrete columns strenghtened by partial jacketing

    Directory of Open Access Journals (Sweden)

    D. B. FERREIRA

    Full Text Available This article presents the study of reinforced concrete columns strengthened using a partial jacket consisting of a 35mm self-compacting concrete layer added to its most compressed face and tested in combined compression and uniaxial bending until rupture. Wedge bolt connectors were used to increase bond at the interface between the two concrete layers of different ages. Seven 2000 mm long columns were tested. Two columns were cast monolithically and named PO (original column e PR (reference column. The other five columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and other columns had a 155 mm by 250mm cross section after the strengthening procedure. Results show that the ultimate resistance of the strengthened columns was more than three times the ultimate resistance of the original column PO, indicating the effectiveness of the strengthening procedure. Detachment of the new concrete layer with concrete crushing and steel yielding occurred in the strengthened columns.

  5. Proceedings of the Canadian oil sands forum 2007 : creating excellence through innovation

    International Nuclear Information System (INIS)

    2007-01-01

    The supply from Canada's oil sands industry is growing at an accelerated pace. This conference was intended for professionals in the oil sands industry seeking updated information on oil sands developments, transportation issues and future market challenges and opportunities. It was attended by a broad range of industry participants who addressed some of the critical issues involved in developing oil sands projects. Despite market opportunities which have resulted in a fast pace of development and continually evolving project plans, there are challenges and uncertainties that must be overcome in order to achieve projected levels of supply growth. It was noted that the business environment in the oil sands industry is continually changing in terms of current supply/market/refining situations and new market developments. The conference also addressed how capital cost and mega-project management issues are being addressed. Expanding market opportunities for Canada's growing oil sands supply were highlighted along with latest developments related to upgrading strategies. Market experts also discussed issues related to synthetic crude, heavy oil markets and the supply and demand of diluents. The sessions were entitled: challenges and opportunities in oil sands; oil sands business outlook; latest project development updates; integration of Canadian oil sands with U.S. refining; and, technology and oil sands innovations.The conference featured 16 presentations, of which 6 have been catalogued separately for inclusion in this database. tabs., figs

  6. Rapid increases in permeability and porosity of bentonite-sand mixtures due to alteration by water vapor

    International Nuclear Information System (INIS)

    Couture, R.A.

    1984-01-01

    Packed columns of canister packing material containing 25% bentonite and 75% quartz or basalt sand, were exposed to water vapor at temperatures up t 260 0 C. The permeabilities of the columns were subsequently measured after complete saturation with liquid water in a pressurized system. Exposure to water vapor caused irreversible increases in permeability by factors of up to 10 5 . After saturation with liquid water, the permeability was nearly independent of temperature. The increases in permeability were due to a large decrease in the ability of the bentonite to swell in water. Calculations suggest that swelling of bentonite altered at 250 0 C was not sufficient to fill the pore spaces. If the pore spaces are filled, the mixture will form an effective barrier against flow, diffusion, and transport of colloids. The results suggest that if bentonite-based canister packing material is exposed even briefly to water vapor at high temperatures in a high-level nuclear waste repository, its performance will be seriously impaired. The problem is less severe if the proportion of bentonite is high and the material is highly compacted. Previous results show significant degradation of bentonite by water vapor at temperatures as low as 150 0 C. This suggests that in some repositories, backfill in tunnels and drifts may also be affected. 9 references, 5 figures, 1 table

  7. Improving the geotechnical behavior of sand through cohesive admixtures

    Directory of Open Access Journals (Sweden)

    Mohie eldin Mohamed Afify Elmashad

    2018-04-01

    Full Text Available Irrigation projects in Egypt have been facing tremendous challenges, mostly is the scarcity of irrigation water. The current research presents the effect of different cohesive admixture on the conductivity of siliceous sand in general and its other geotechnical properties. Two different types of conventional swelling clay from (Toshka, 6th of October as well as bentonite were used to construct the irrigation canals and embankment. The results indicated that increase in the plasticity properties of the treated soil also decrease the permeability and infiltration. Moreover, the dry density of 2.08 t/m3 was obtained from sand and 20% 6th of October mixture, also the CBR of 31.20% were obtained from sand and 8% 6th of October mixture. Increasing the bentonite ratio increases the cohesion and decreasing the permeability. The swelling ratios of sand 6th of October Clay mixture is equal to 0.28%, and the fictitious stress at which the swelling ratio is nil, is equal to 16 kPa. Keywords: Sand, Swelling clay, Bentonite, Compaction test, Consolidation test, Triaxial test

  8. Recent advances in column switching sample preparation in bioanalysis.

    Science.gov (United States)

    Kataoka, Hiroyuki; Saito, Keita

    2012-04-01

    Column switching techniques, using two or more stationary phase columns, are useful for trace enrichment and online automated sample preparation. Target fractions from the first column are transferred online to a second column with different properties for further separation. Column switching techniques can be used to determine the analytes in a complex matrix by direct sample injection or by simple sample treatment. Online column switching sample preparation is usually performed in combination with HPLC or capillary electrophoresis. SPE or turbulent flow chromatography using a cartridge column and in-tube solid-phase microextraction using a capillary column have been developed for convenient column switching sample preparation. Furthermore, various micro-/nano-sample preparation devices using new polymer-coating materials have been developed to improve extraction efficiency. This review describes current developments and future trends in novel column switching sample preparation in bioanalysis, focusing on innovative column switching techniques using new extraction devices and materials.

  9. Sustainable use of oil sands for geotechnical construction and road building

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2012-02-01

    Full Text Available Oil sands are natural deposits of bituminous sand materials that are mined and processed for crude oil. They are routinely used in oil sand fields for building temporary and sometimes permanent roads serving mining and hauling activities. Although...

  10. The influence of sand content on swelling pressures and structure developed in statically compacted Na-bentonite

    International Nuclear Information System (INIS)

    Gray, M.N.; Cheung, S.C.H.; Dixon, D.A.

    1984-09-01

    A laboratory investigation of the vertical and lateral swelling pressures developed in statically compacted, air-dry specimens of sodium (Na)-bentonite:silica sand mixtures as they are saturated in confined conditions with double-distilled, deionized water is described. The results are interpreted with the aid of observations of the compacted soil structures made in a scanning electron microscope. It is shown that the sand acts as an inert filler material and vertical swelling pressures are controlled by a parameter termed the effective clay dry density (qsub(c)). A limiting value of qsub(c) exists below which vertical and lateral swelling pressures do not differ and are theoretically predictable. Above this value, vertical pressures exceed lateral ones. This is related to a change from an isotropic to an anisotropic soil fabric as qsub(c) is increased above the limiting value

  11. Experimental Investigation of Evaporation and Drainage in Wettable and Water-Repellent Sands

    Directory of Open Access Journals (Sweden)

    Dae Hyun Kim

    2015-05-01

    Full Text Available This study presents experimental results on evaporation and drainage in both wettable and water-repellent sands whose surface wettability was artificially modified by silanization. The 2D optical and 3D X-ray computed tomographic imaging was performed during evaporation and the water retention during cyclic drainage and infiltration was measured to assess effects of wettability and initial wetting conditions. The evaporation gradually induces its front at the early stage advance regardless of the wettability and sand types, while its rate becomes higher in water-repellent Ottawa sand than the wettable one. Jumunjin sand which has a smaller particle size and irregular particle shape than Ottawa sand exhibits a similar evaporation rate independent of wettability. Water-repellent sand can facilitate the evaporation when both wettable and water-repellent sands are naturally in contact with each other. The 3D X-ray imaging reveals that the hydraulically connected water films in wettable sands facilitate the propagation of the evaporation front into the soil such that the drying front deeply advances into the soil. For cyclic drainage-infiltration testing, the evolution of water retention is similar in both wettable and water-repellent sands when both are initially wet. However, when conditions are initially dry, water-repellent sands exhibit low residual saturation values. The experimental observations made from this study propose that the surface wettability may not be a sole factor while the degree of water-repellency, type of sands, and initial wetting condition are predominant when assessing evaporation and drainage behaviors.

  12. The Karakum and Kyzylkum sand seas dynamics; mapping and palaeoclimatic interpretations

    Science.gov (United States)

    Maman, Shimrit; Blumberg, Dan G.; Tsoar, Haim; Porat, Naomi

    2015-04-01

    Sand seas are large basins in deserts that are mantled by wind-swept sand and that exhibit varying degrees of vegetation cover. Wilson (1973) was the first to globally map and classify sand seas. Beyond Wilson's maps, however, little research has been published regarding the Karakum and Kyzylkum sand seas of Central Asia. Wilson's maps delineate active ergs from inactive ergs based solely on precipitation. His assumption of annual average rainfall as a factor determining mobility vs. stability of sand seas is too simplistic and does not take into consideration other factors such as biogenic soil crusts and wind power, both of which are known to have major effects on the dynamics of sand dunes. Literature related to mapping and classifying the Central Asian ergs by remote sensing or sand sea classification state (stable/active) is lacking. Moreover, the palaeoclimatic significance of dunes in Central Asia is difficult to assess, as there has been few studies of dune stratigraphy and numerical ages are lacking. Optically stimulated luminescence (OSL) is a firm optical dating method that is used to determine the elapsed time since quartz grains were last exposed to sunlight, thus, their burial. Yet, absolute ages indicating mobilization and stabilization of these sands, are still inadequately known and are here under discussion. The broad concern of this research was to determine the dynamics of the Central Asian sand seas and study the palaeoclimatic changes that brought to their stabilization. As there are no reliable maps or aeolian discussion of these sands, establishment of a digital data base was initially conducted, focusing on identifying and mapping these sand seas. The vast area and inaccessibility make traditional mapping methods virtually impossible. A variety of space-borne imagery both optical and radar, with varying spectral and spatial resolutions was used. These images provided the basis for mapping sand distribution, dune forms, and vegetation cover

  13. Characteristics and Dynamics of a Large Sub-Tidal Sand Wave Field—Habitat for Pacific Sand Lance (Ammodytes personatus, Salish Sea, Washington, USA

    Directory of Open Access Journals (Sweden)

    H. Gary Greene

    2017-10-01

    Full Text Available Deep-water sand wave fields in the San Juan Archipelago of the Salish Sea and Pacific Northwest Washington, USA, have been found to harbor Pacific sand lance (PSL, Ammodytes personatus, a critical forage fish of the region. Little is known of the dynamics of these sand waves and the stability of the PSL sub-tidal habitats. Therefore, we have undertaken an initial investigation to determine the dynamic conditions of a well-known PSL habitat in the San Juan Channel within the Archipelago using bottom sediment sampling, an acoustical doppler current profiling (ADCP system, and multi-beam echo sounder (MBES bathymetry. Our study indicates that the San Juan Channel sand wave field maintained its shape and bedforms geometry throughout the years it has been studied. Based on bed phase diagrams for channelized bedforms, the sand waves appear to be in a dynamic equilibrium condition. Sea level rise may change the current regime within the Archipelago and may alter some of the deep-water or sub-tidal PSL habitats mapped there. Our findings have global significance in that these dynamic bedforms that harbor PSL and sand-eels elsewhere along the west coast of North America and in the North Sea may also be in a marginally dynamic equilibrium condition and may be prone to alteration by sea level rise, indicating an urgency in locating and investigating these habitats in order to sustain the forage fish.

  14. Integration of the White Sands Complex into a Wide Area Network

    Science.gov (United States)

    Boucher, Phillip Larry; Horan, Sheila, B.

    1996-01-01

    The NASA White Sands Complex (WSC) satellite communications facility consists of two main ground stations, an auxiliary ground station, a technical support facility, and a power plant building located on White Sands Missile Range. When constructed, terrestrial communication access to these facilities was limited to copper telephone circuits. There was no local or wide area communications network capability. This project incorporated a baseband local area network (LAN) topology at WSC and connected it to NASA's wide area network using the Program Support Communications Network-Internet (PSCN-I). A campus-style LAN is configured in conformance with the International Standards Organization (ISO) Open Systems Interconnect (ISO) model. Ethernet provides the physical and data link layers. Transmission Control Protocol and Internet Protocol (TCP/IP) are used for the network and transport layers. The session, presentation, and application layers employ commercial software packages. Copper-based Ethernet collision domains are constructed in each of the primary facilities and these are interconnected by routers over optical fiber links. The network and each of its collision domains are shown to meet IEEE technical configuration guidelines. The optical fiber links are analyzed for the optical power budget and bandwidth allocation and are found to provide sufficient margin for this application. Personal computers and work stations attached to the LAN communicate with and apply a wide variety of local and remote administrative software tools. The Internet connection provides wide area network (WAN) electronic access to other NASA centers and the world wide web (WWW). The WSC network reduces and simplifies the administrative workload while providing enhanced and advanced inter-communications capabilities among White Sands Complex departments and with other NASA centers.

  15. Chromatographic properties PLOT multicapillary columns.

    Science.gov (United States)

    Nikolaeva, O A; Patrushev, Y V; Sidelnikov, V N

    2017-03-10

    Multicapillary columns (MCCs) for gas chromatography make it possible to perform high-speed analysis of the mixtures of gaseous and volatile substances at a relatively large amount of the loaded sample. The study was performed using PLOT MCCs for gas-solid chromatography (GSC) with different stationary phases (SP) based on alumina, silica and poly-(1-trimethylsilyl-1-propyne) (PTMSP) polymer as well as porous polymers divinylbenzene-styrene (DVB-St), divinylbenzene-vinylimidazole (DVB-VIm) and divinylbenzene-ethylene glycol dimethacrylate (DVB-EGD). These MCCs have the efficiency of 4000-10000 theoretical plates per meter (TP/m) and at a column length of 25-30cm can separate within 10-20s multicomponent mixtures of substances belonging to different classes of chemical compounds. The sample amount not overloading the column is 0.03-1μg and depends on the features of a porous layer. Examples of separations on some of the studied columns are considered. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. On Foundation Improvement By Sand Replacement | Abam | Global ...

    African Journals Online (AJOL)

    This paper describes a simple foundation improvement method involving the replacement of poor foundation bearing soils with sand and the resultant improvement in bearing capacity and the minimization of settlement at the site of a large storage tank. Minimum thickness of sand replacement for various foundation loads ...

  17. Optimization of Beam Transmission of PAL-PNF Electron Linac

    Energy Technology Data Exchange (ETDEWEB)

    Shin, S. G.; Kim, S. K.; Kim, E. A. [Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2012-05-15

    The PNF (Pohang Neutron Facility) electron Linac is providing converted neutrons and photons from electron beams to users for nuclear physics experiments and high energy gamma-ray exposures. This linac is capable of producing 100 MeV electron beams with a beam current of pulsed 100 mA. The pulse length is 2 {mu}s and the pulse repetition rate is typically 30 Hz. This linac consists of two SLAC-type S-band accelerating columns and the thermionic RF gun. They are powered by one klystron and the matching pulse modulator. The electron beams emitted from the RF gun are bunched as they pass through the alpha magnet and are injected into the accelerating column thereafter. In this paper, we discuss procedures and results of the beam transmission optimization with technical details of the accelerator system. We also briefly discuss the future upgrade plan to obtain short-pulse or electron beams for neutron TOF experiments by adopting a triode type thermionic DC electron gun

  18. Ask Dr. Sue: Tree Climbing and Care of Sand Play Areas.

    Science.gov (United States)

    Aronson, Susan S.

    1993-01-01

    Discusses safety aspects of tree climbing and the use of sand in outdoor play areas at day care centers. Specifies ways to prune trees so that they are unclimbable and methods for maintaining sand areas. Includes a recipe for sand disinfectant. (MDM)

  19. Differences and commonalities impregnation of dry and wet sand

    Directory of Open Access Journals (Sweden)

    Maujuda МUZAFFAROVA

    2014-09-01

    Full Text Available The article is devoted to research new methods of physic-chemical methods of preventing deflation to protect railways and highways from such phenomena as exogenous sand drifts. In particular, first studied the possibility of using binders in sand wet state. Results can significantly extend the scope of the method, and identified with particular impregnation maintaining stability requirements protective cover reduces both the concentration previously recommended binders, and their costs, thereby securing implementation in practice of shifting sands resource-saving technology.

  20. Research for the development of the crushed sand (II)

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chul Whan; Kang, Sun Duck; Min, Jeong Sik; Synn, Joong Ho; Park, Chan [Korea Institute of Geology Mining and Materials, Taejon (Korea)

    1998-12-01

    The sand obtained from river is not sufficient in amount for the demand of construction industry. The production of sand from sea and mountain is rapidly increasing for the substitution of the river sand. The industry of the crushed sand has recently been bricked for the above. Crushing, classification and dewatering are the main processes in the crushed sand production. This report concentrates the improvement of classification technology and the quality of ready mixed concrete. Air separator with testing size for the classification in the process of dry system was developed by the Yeung Nam university. This plant has the excellent efficiency for the collection of fine powder, but needs the improvement for separating function. The collection efficiency of the testing size air separator is reached to 99% in the condition of high revolution and low feeding speed. The classification efficiency is checked about 50% maximum in the condition of 200 rpm and dry sample. Energy saving test was carried out in the production process of the dry system with the rock samples of 14-17% of water content. The classification efficiency for dewatering sample passed the heating process was analysed 91.5%. But that for high water content sample skipped the heating process was analysed more or less 77%. Even though the heating process causes the classification efficiency being high, the energy consumption can also cause the price of the crushed sand high. Water content of sample as the effective element for the optimization of classification efficiency and energy saving should be studied next year. The quality of crushed sand in the mixing design. The test was carried out with the various content in mixing, the strength of ready mixed concrete has the maximum for the mould with 50-60% content of crushed sand. This strength is higher by 5-30% than 30% content and by 20-32% than 0% content, which means that the industry has the possibility of progress. (author). 10 refs., 31 tabs., 49