WorldWideScience

Sample records for repacked soil columns

  1. Structure-Dependent Water-Induced Linear Reduction Model for Predicting Gas Diffusivity and Tortuosity in Repacked and Intact Soil

    DEFF Research Database (Denmark)

    Møldrup, Per; Chamindu, Deepagoda; Hamamoto, Shoichiro;

    2013-01-01

    but also on the local-scale variability of these. Different predictive models have been developed to estimate Dp in intact and repacked soil, but clear guidelines for model choice at a given soil state are lacking. In this study, the water-induced linear reduction (WLR) model for repacked soil is made...... adaptive for different soil structure conditions (repacked, intact) by introducing a media complexity factor (Cm) in the dry media term of the model. With Cm = 1, the new structure-dependent WLR (SWLR) model accurately predicted soil-gas diffusivity (Dp/Do, where Do is the gas diffusion coefficient in free...... air) in repacked soils containing between 0 and 54% clay. With Cm = 2.1, the SWLR model on average gave excellent predictions for 290 intact soils, performing well across soil depths, textures, and compactions (dry bulk densities). The SWLR model generally outperformed similar, simple Dp/Do models...

  2. Leaching of human pathogens in repacked soil lysimeters and contamination of potato tubers under subsurface drip irrigation in Denmark

    DEFF Research Database (Denmark)

    Forslund, Anita; Plauborg, Finn; Andersen, Mathias Neumann

    2011-01-01

    to groundwater. However, viruses may leach to groundwater and represent a health risk as for some viruses only few virus particles are needed to cause human disease. The bacterial pathogens and the phage 28B were found on the potato samples harvested just after the application of microbial tracers was terminated......The risk for contamination of potatoes and groundwater through subsurface drip irrigation with low quality water was explored in 30 large-scale lysimeters containing repacked coarse sand and sandy loam soils. The human pathogens, Salmonella Senftenberg, Campylobacter jejuni and Escherichia coli O...... loam soil. The added bacterial pathogens were not found in any leachate samples during the entire study period of 212 days. Under the study conditions with repacked soil, limited macropores and low water velocity, bacterial pathogens seemed to be retained in the soil matrix and died-off before leaching...

  3. The coupled mobilizations and transport of dissolved organic matter and metals (Cu and Zn) in soil columns

    NARCIS (Netherlands)

    Zhao, L.Y.L.; Schulin, R.; Weng, L.P.; Nowack, B.

    2007-01-01

    Dissolved organic carbon (DOC) is a key component involved in metal displacement in soils. In this study, we investigated the concentration profiles of soil-borne DOC, Cu and Zn at various irrigation rates with synthetic rain water under quasi steady-state conditions, using repacked soil columns wit

  4. 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 Reef...... consumption and N-2 production. The N:O-2 slope of 0.114 implied that about 75% of all the nitrogen mineralized was denitrified. A 4-fold increase in sediment column length (from 10 to 40 cm) resulted in an overall increase in oxygen consumption (1.6-fold), TCO2 production (1.8-fold), and denitrification (1...... enhance the development of microniches (i.e., steep oxygen gradients) within porous carbonate sands, perhaps providing optimum conditions for denitrification. The denitrification peak fell within the broad range of advection rates (often on scales of 1-100 L m(-2) h(-1)) typically found on continental...

  5. Nitrogen and Carbon Leaching in Repacked Sandy Soil with Added Fine Particulate Biochar

    DEFF Research Database (Denmark)

    Bruun, Esben W.; Petersen, Carsten; Strobel, Bjarne W.

    2012-01-01

    Biochar amendment to soil may affect N turnover and retention, and may cause translocation of dissolved and particulate C. We investigated effects of three fine particulate biochars made of wheat (Triticum aestivum L.) straw (one by slow pyrolysis and two by fast pyrolysis) on N and C leaching fr...

  6. Column Holdup Formula of Soil Solute Transport

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The shortcomings of the present two formulae for describing column holdup are analyzed and deductions are made to find a new formula. The column holdup, Hw, described by the new formula is dimensional,and related to soil solute transport kinesis and column physical properties. Compared with the other two column holdups, Hw is feasible to describe dimensional column holdup during solute transport process. The relationships between Hw and retardation factor, R, in different solute transport boundary conditions are established.

  7. 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.

  8. 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.

  9. Boron and Zinc Transport Through Intact Columns of Calcareous Soils

    Institute of Scientific and Technical Information of China (English)

    M. MAHMOOD-UL-HASSAN; M. S. AKHTAR; G. NABI

    2008-01-01

    Leaching of boron (B) and zinc (Zn) can be significant in some pedomorphic conditions, which can cause contamination of shallow groundwater and economic losses. Boron and Zn adsorption and transport was studied using 8.4 cm diameter ×28 cm long intact columns from two calcareous soil series with differing clay contents and vadose zone structures:Lyallpur soil series, clay loam (fine-silty, mixed, hyperthermic Ustalfic Haplargid), and Sultanpur soil series, sandy loam (coarse-silty, mixed, hyperthermic Ustollic Camborthid). The adsorption isotherms were developed by equilibrating soil with 0.01 mol L-1 CaCl2 aqueous solution containing varying amounts of B and Zn and were fitted to the Langmuir equation. The B and Zn breakthrough curves were fitted to the two-domain convective-dispersive equation. At the end of the leaching experiment, 0.11 L 10 g L-1 blue dye solution was also applied to each column to mark the flow paths.The Lyallpur soil columns had a slightly greater adsorption partition coefficient both for B and Zn than the Sultanpur soil columns. In the Lyallpur soil columns, B arrival was immediate but the peak concentration ratio (the concentration in solution at equilibrium/concentration applied) was lower than that in the Sultanpur soil columns. The breakthrough of B in the Sultanpur soil columns occurred after about 10 cm of cumulative drainage in both the columns; the rise in effluent concentration was fast and the peak concentration ratio was almost 1. Zinc leaching through the soil columns was very limited as only one column from the Lyallpur soil series showed Zn breakthrough in the effluent where the peak concentration ratio was only 0.05. This study demonstrates the effect of soil structure on B transport and has implications for the nutrient management in field soils.

  10. Mitigation of Liquefaction in Sandy Soils Using Stone Columns

    Science.gov (United States)

    Selcuk, Levent; Kayabalı, Kamil

    2010-05-01

    Soil liquefaction is one of the leading causes of earthquake-induced damage to structures. Soil improvement methods provide effective solutions to reduce the risk of soil liquefaction. Thus, soil ground treatments are applied using various techniques. However, except for a few ground treatment methods, they generally require a high cost and a lot of time. Especially in order to prevent the risk of soil liquefaction, stone columns conctructed by vibro-systems (vibro-compaction, vibro-replacement) are one of the traditional geotechnical methods. The construction of stone columns not only enhances the ability of clean sand to drain excess pore water during an earthquake, but also increases the relative density of the soil. Thus, this application prevents the development of the excess pore water pressure in sand during earthquakes and keeps the pore pressure ratio below a certain value. This paper presents the stone column methods used against soil liquefaction in detail. At this stage, (a) the performances of the stone columns were investigated in different spacing and diameters of columns during past earthquakes, (b) recent studies about design and field applications of stone columns were presented, and (c) a new design method considering the relative density of soil and the capacity of drenage of columns were explained in sandy soil. Furthermore, with this new method, earthquake performances of the stone columns constructed at different areas were investigated before the 1989 Loma Prieta and the 1994 Northbridge earthquakes, as case histories of field applications, and design charts were compiled for suitable spacing and diameters of stone columns with consideration to the different sandy soil parameters and earhquake conditions. Key Words: Soil improvement, stone column, excess pore water pressure

  11. Stone Columns - Determination of the soil improvement factor

    Science.gov (United States)

    Pivarč, J.

    2011-09-01

    A stone column is one of the soil stabilizing methods that is used to increase strength, decrease the compressibility of soft and loose fine graded soils, accelerate a consolidation effect and reduce the liquefaction potential of soils. The columns consist of compacted gravel or crushed stone arranged by a vibrator. This paper deals with Priebe's theory (1976) on the design of an improvement factor, which belongs among the most used analytical methods and also describes the numerical and laboratory models of stone columns. The improvement factors calculated from numerical and laboratory models are compared with the improvement factors resulting from Priebe's theory.

  12. SURFACTANT ENHANCED REMEDIATION OF SOIL COLUMNS CONTAMINATED BY RESIDUAL TETRACHLOROETHYLENE

    Science.gov (United States)

    The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa sand was evaluated in four column experiments. Residual PCE was emplaced by injecting 14C-labeled PCE into water-saturated soil columns and displacing the free product ...

  13. 19 CFR 134.34 - Certain repacked articles.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Certain repacked articles. 134.34 Section 134.34... TREASURY COUNTRY OF ORIGIN MARKING Exceptions to Marking Requirements § 134.34 Certain repacked articles. (a) Exception for repacked articles. An exception under § 134.32(d) may be authorized in...

  14. Modeling atrazine transport in soil columns with HYDRUS-1D

    Directory of Open Access Journals (Sweden)

    John Leju CELESTINO LADU

    2011-09-01

    Full Text Available Both physical and chemical processes affect the fate and transport of herbicides. It is useful to simulate these processes with computer programs to predict solute movement. Simulations were run with HYDRUS-1D to identify the sorption and degradation parameters of atrazine through calibration from the breakthrough curves (BTCs. Data from undisturbed and disturbed soil column experiments were compared and analyzed using the dual-porosity model. The study results show that the values of dispersivity are slightly lower in disturbed columns, suggesting that the more heterogeneous the structure is, the higher the dispersivity. Sorption parameters also show slight variability, which is attributed to the differences in soil properties, experimental conditions and methods, or other ecological factors. For both of the columns, the degradation rates were similar. Potassium bromide was used as a conservative non-reactive tracer to characterize the water movement in columns. Atrazine BTCs exhibited significant tailing and asymmetry, indicating non-equilibrium sorption during solute transport. The dual-porosity model was verified to best fit the BTCs of the column experiments. Greater or lesser concentration of atrazine spreading to the bottom of the columns indicated risk of groundwater contamination. Overall, HYDRUS-1D successfully simulated the atrazine transport in soil columns.

  15. Mobility and degradation of trinitrotoluene/metabolites in soil columns: effect of soil organic carbon content.

    Science.gov (United States)

    Singh, Neera; Hennecke, Dieter; Hoerner, Jennifer; Koerdel, Werner; Schaeffer, Andreas

    2008-06-01

    There has been increasing interest in enhancing natural attenuation of munitions-contaminated soils. Present study reports the effect of increasing soil organic matter content on fate and mobility of trinitrotoluene (TNT) and metabolites in soil columns. This study was performed using 30-cm-long columns containing a top 5 cm of contaminated soil as a source layer and an uncontaminated soil (25 cm) adjusted to 0.5, 1.0, 1.5 and 3.0% organic carbon (OC) content using compost. Contaminated soil layer was fortified with uniformly ring-labeled (14)C-trinitrotoluene (TNT) or 2,4-dinitrotoluene (DNT); in total there were 8 treatments. Columns were leached with synthetic rain water under unsaturated flow conditions in downside up direction. There was significant increase in the retention of both (14)C-TNT and (14)C-DNT in soils with increasing soil OC content and in 3.0% soil OC content column degradation of TNT and metabolites from contaminated soil was significantly increased and resulted in greater soil-bound residues. Formation of monoamino-dinitrotoluene (ADNTs), diamino-mononitrotoluene (DANTs) and monoamino-mononitrotoluene (ANTs) metabolites was greatly enhanced with increase in OC content of soils. Study suggests that increasing OC content of contaminated soil to 3.0% significantly enhanced the reduction of nitroaromatics to more polar amine metabolites and the formation of soil-bound residues.

  16. Simulation study on vertical transport of atrazine in soil column

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A simulation experiment on vertical transport of herbicide atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) in soil column was conducted using lysimeter system. The atrazine concentrations in leaching water and soil samples in column at 8 layers with 10 cm thick of each layer were detected by high-performance liquid chromatography. The results show total atrazine amount in leaching water increases nonlinearly with the leaching time and the herbicide application rate, and the atrazine concentrations in column soil decrease with the vertical depth after water leaching. The distribution of atrazine mass in the system after 154 days were that among the applied atrazine, 0.3 % is out through leaching water, 1% is methanol extractable residues in soil, 46 % is methanol nonextractable residues in soil, and 52 % is other loss (including volatilization and degradation). The study indicates movement of atrazine in agriculture soil may not only have relation to the properties of herbicide, but also to the herbicide application history.

  17. Simulation study on vertical transport of atrazine in soil column

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A simulation experiment on vertical transport of herbicide atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) in soil column was conducted using lysimeter system. The atrazine concentrations in leaching water and soil samples in column at 8 layers with 10 cm thick of each layer were detected by high-performance liquid chromatography. The results show total atrazine amount in leaching water increases nonlinearly with the leaching time and the herbicide application rate, and the atrazine concentrations in column soil decrease with the vertical depth after water leaching. The distribution of atrazine mass in the system after 154 days were that among the applied atrazine, 0.3 % is out through leaching water, 1% is methanol extractable residues in soil, 46 % is methanol nonextractable residues in soil, and 52 % is other loss (including volatilization and degradation). The study indicates movement of atrazine in agriculture soil may not only have relation to the properties of herbicide, but also to the herbicide application history.

  18. Determination of solute organic concentration in contaminated soils using a chemical-equilibrium soil column system

    DEFF Research Database (Denmark)

    Gamst, Jesper; Kjeldsen, Peter; Christensen, Thomas Højlund

    2007-01-01

    Groundwater risk assessment of contaminated soils implies determination of the solute concentration leaching out of the soil. Determination based on estimation techniques or simple experimental batch approach has proven inadequate. Two chemical equilibrium soil column leaching tests...... for determination of solute concentration in a contaminated soil were developed; (1) a chemical Equilibrium and Recirculation column test for Volatile organic chemicals (ER-V) and (2) a chemical Equilibrium and Recirculation column test for Hydrophobic organic chemicals (ER-H). The two test systems were evaluated...... to measure solute phase concentration of PAHs in contaminated soils. Overall a reliable and reproducable system for determining solute concentration of a wide range of organic compounds in contaminated soils has been developed....

  19. Effect of sulfate fertilization on soil biota in grassland columns

    Science.gov (United States)

    Ikoyi, Israel; Donohue, John; Fowler, Andrew; Schmalenberger, Achim

    2017-04-01

    Sulfur (S) is an important macronutrient element in plant nutrition as a component of protein, enzymes, enzyme cofactors as well as being the major constituent of the amino acids cysteine and methionine. Organically bound S is the predominant form of S in the soil constituting up to 95% of S in agricultural soils. The most important form of S in terms of plant nutrition is inorganic sulfate which forms only about 5% of the total soil S content. Air pollution was the major source of S (as SO2) for plants, with up to 80% of the S obtained from this source. However, common effects of S limitation on crops such as chlorosis, yield reduction, and decrease in crop quality are becoming increasingly evident as atmospheric S supply has decreased in recent years. Recent research has shown that organically-bound S in soils is also plant-bioavailable, likely due to interconversion of organic S forms to inorganic sulfate by soil microbes. In this study, soil columns were setup in a greenhouse using moderate S (equivalent to Wisconsin S soil availability index of below 30) soils. The columns were planted with Lolium perenne and fertilized with 0 (control), 5 (low), 10 (medium) and 20 (high) kg/ha sulfate S alongside a full complement of other nutrients. Results after 14 weeks of management show a significant decrease (Pfertilization. In addition, soil from the top 20 cm of the column had significantly higher sulfatase activity compared to the bottom 20 cm. The medium and high S treatments had significantly higher grass dry matter yield compared to the control and low S treatments. All S treatments significantly shifted the bacterial community structure compared to the control. Overall, our preliminary results suggest that applying 5 kg/ ha S had similar effects on the soil biota as the control while the application of medium and high S had similar effects on most parameters. Moreover, this study has shown that S should not be overlooked in grassland nutrition as is often the

  20. Alfalfa Responses to Gypsum Application Measured Using Undisturbed Soil Columns

    Directory of Open Access Journals (Sweden)

    Rebecca Tirado-Corbalá

    2017-07-01

    Full Text Available Gypsum is an excellent source of Ca and S, both of which are required for crop growth. Large amounts of by-product gypsum [Flue gas desulfurization gypsum-(FGDG] are produced from coal combustion in the United States, but only 4% is used for agricultural purposes. The objective of this study was to evaluate the effects of (1 untreated, (2 short-term (4-year annual applications of gypsum totaling 6720 kg ha−1, and (3 long-term (12-year annual applications of gypsum totaling 20,200 kg ha−1 on alfalfa (Medicago sativa L. growth and nutrient uptake, and gypsum movement through soil. The study was conducted in a greenhouse using undisturbed soil columns of two non-sodic soils (Celina silt loam and Brookston loam. Aboveground growth of alfalfa was not affected by gypsum treatments when compared with untreated (p > 0.05. Total root biomass (0–75 cm for both soils series was significantly increased by gypsum application (p = 0.04, however, increased root growth was restricted to 0–10 cm depth. Soil and plant analyses indicated no unfavorable environmental impact from of the 4-year and 12-year annual application of FGDG. We concluded that under sufficient water supply, by-product gypsum is a viable source of Ca and S for land application that might benefit alfalfa root growth, but has less effect on aboveground alfalfa biomass production. Undisturbed soil columns were a useful adaptation of the lysimeter method that allowed detailed measurements of alfalfa nutrient uptake, root biomass, and yield and nutrient movement in soil.

  1. Water table fluctuations and soil biogeochemistry: An experimental approach using an automated soil column system

    Science.gov (United States)

    Rezanezhad, F.; Couture, R.-M.; Kovac, R.; O'Connell, D.; Van Cappellen, P.

    2014-02-01

    Water table fluctuations significantly affect the biological and geochemical functioning of soils. Here, we introduce an automated soil column system in which the water table regime is imposed using a computer-controlled, multi-channel pump connected to a hydrostatic equilibrium reservoir and a water storage reservoir. The potential of this new system is illustrated by comparing results from two columns filled with 45 cm of the same homogenized riparian soil. In one soil column the water table remained constant at -20 cm below the soil surface, while in the other the water table oscillated between the soil surface and the bottom of the column, at a rate of 4.8 cm d-1. The experiment ran for 75 days at room temperature (25 ± 2 °C). Micro-sensors installed at -10 and -30 cm below the soil surface in the stable water table column recorded constant redox potentials on the order of 600 and -200 mV, respectively. In the fluctuating water table column, redox potentials at the same depths oscillated between oxidizing (∼700 mV) and reducing (∼-100 mV) conditions. Pore waters collected periodically and solid-phase analyses on core material obtained at the end of the experiment highlighted striking geochemical differences between the two columns, especially in the time series and depth distributions of Fe, Mn, K, P and S. Soil CO2 emissions derived from headspace gas analysis exhibited periodic variations in the fluctuating water table column, with peak values during water table drawdown. Transient redox conditions caused by the water table fluctuations enhanced microbial oxidation of soil organic matter, resulting in a pronounced depletion of particulate organic carbon in the midsection of the fluctuating water table column. Denaturing Gradient Gel Electrophoresis (DGGE) revealed the onset of differentiation of the bacterial communities in the upper (oxidizing) and lower (reducing) soil sections, although no systematic differences in microbial community structure

  2. Modelling soil water content variations under drought stress on soil column cropped with winter wheat

    Directory of Open Access Journals (Sweden)

    Csorba Szilveszter

    2014-12-01

    Full Text Available Mathematical models are effective tools for evaluating the impact of predicted climate change on agricultural production, but it is difficult to test their applicability to future weather conditions. We applied the SWAP model to assess its applicability to climate conditions, differing from those, for which the model was developed. We used a database obtained from a winter wheat drought stress experiment. Winter wheat was grown in six soil columns, three having optimal water supply (NS, while three were kept under drought-stressed conditions (S. The SWAP model was successfully calibrated against measured values of potential evapotranspiration (PET, potential evaporation (PE and total amount of water (TSW in the soil columns. The Nash-Sutcliffe model efficiency coefficient (N-S for TWS for the stressed columns was 0.92. For the NS treatment, we applied temporally variable soil hydraulic properties because of soil consolidation caused by regular irrigation. This approach improved the N-S values for the wetting-drying cycle from -1.77 to 0.54. We concluded that the model could be used for assessing the effects of climate change on soil water regime. Our results indicate that soil water balance studies should put more focus on the time variability of structuredependent soil properties.

  3. Bioremediation of carbofuran contaminated soil under saturated condition: soil column study.

    Science.gov (United States)

    Plangklang, Pensri; Reungsang, Alissara; Suphannafai, Wisarut

    2012-06-01

    Disturbed soil columns, 5.8 cm in diameter and 25 cm in length, were used as a basic model to simulate the movement of carbofuran in rice field soil under saturated conditions. Bioaugmentation using a specific carbofuran degrader, Burkholderia sp. PCL3, in free and immobilized cell forms and biostimulation using rice straw as organic amendment were applied with the aim of enhancing the degradation of carbofuran in soil and to prevent the movement of carbofuran along with the flow through. In the abiotic control and the treatment with only indigenous microorganisms, the mass recovery percentage of carbofuran in the effluent was 52.1 and 22.5%, respectively. The application of bioaugmentation or biostimulation significantly enhanced carbofuran degradation in soil and reduced the movement of carbofuran as indicated by a low mass recovery percentage of carbofuran in the effluent of 14.6-15.5%. A low efficiency of carbofuran removal was obtained from the soil column with bioaugmentation together with biostimulation treatments in which the mass recovery percentage of carbofuran in the effluent was in the range of 22.1-22.6%. Sorption of carbofuran to soil, rice straw and corncob, formation of carbofuran metabolite and colony forming unit (CFU) and pH variation with the time were also investigated during column operation.

  4. 19 CFR 134.26 - Imported articles repacked or manipulated.

    Science.gov (United States)

    2010-04-01

    ... requirements is intended to be repacked in retail containers (e.g., blister packs) after its release from...., blister packs), while still in my possession, the new container(s) will not conceal or obscure the...

  5. Nutrient Release from Disturbance of Infiltration System Soils during Construction

    Directory of Open Access Journals (Sweden)

    Daniel P. Treese

    2012-01-01

    Full Text Available Subsurface infiltration and surface bioretention systems composed of engineered and/or native soils are preferred tools for stormwater management. However, the disturbance of native soils, especially during the process of adding amendments to improve infiltration rates and pollutant removal, may result in releases of nutrients in the early life of these systems. This project investigated the nutrient release from two soils, one disturbed and one undisturbed. The disturbed soil was collected intact, but had to be air-dried, and the columns repacked when soil shrinkage caused bypassing of water along the walls of the column. The undisturbed soil was collected and used intact, with no repacking. The disturbed soil showed elevated releases of nitrogen and phosphorus compared to the undisturbed soil for approximately 0.4 and 0.8 m of runoff loading, respectively. For the undisturbed soil, the nitrogen release was delayed, indicating that the soil disturbance accelerated the release of nitrogen into a very short time period. Leaving the soil undisturbed resulted in lower but still elevated effluent nitrogen concentrations over a longer period of time. For phosphorus, these results confirm prior research which demonstrated that the soil, if shown to be phosphorus-deficient during fertility testing, can remove phosphorus from runoff even when disturbed.

  6. Effects of methane on the microbial populations and oxidation rates in different landfill cover soil columns.

    Science.gov (United States)

    He, Ruo; Ruan, Aidong; Shen, Dong-Sheng

    2007-05-01

    A considerable fraction of methane produced in landfills is oxidized by landfill cover soils. In this work, microbial populations and oxidation rates developed in response to the presence of methane were studied in three soil columns simulated landfill cover soil environments. The population of aerobic heterotrophic bacteria was highest in the waste soil, middle in the clay soil, and lowest in the red soil. After exposure to methane-rich environments, the populations of methanotrophic bacteria showed increases in the waste and clay soils. The population of methanotrophic bacteria increased from 30.77x10(4) to 141.77x10(4) cfu g d.w.-1 in the middle layer of the waste soil column as a function of exposure to methane for 120 days. The populations of methanotrophic bacteria were correlated with the potential methane oxidation rates in the waste and clay soils, respectively. The topsoil was observed to be dried in the three soil columns. Most of methane oxidation occurred at the depth of between 10 and 20 cm in the waste soil column, while it took place mainly at the depth of between 20 and 30 cm in the clay soil column.

  7. Nitrogen transformations and greenhouse gas emissions from a riparian wetland soil: An undisturbed soil column study

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Leoz, Borja [Department of Chemical and Environmental Engineering, University of the Basque Country, UPV/EHU, E-48013 Bilbao (Spain); Antigueedad, Inaki [Department of Geodynamic, University of the Basque Country, UPV/EHU, E-48940 Leioa (Spain); Garbisu, Carlos [Department of Ecosystems, NEIKER-Tecnalia, E-48160 Derio (Spain); Ruiz-Romera, Estilita, E-mail: estilita.ruiz@ehu.es [Department of Chemical and Environmental Engineering, University of the Basque Country, UPV/EHU, E-48013 Bilbao (Spain)

    2011-01-15

    Riparian wetlands bordering intensively managed agricultural fields can act as biological filters that retain and transform agrochemicals such as nitrate and pesticides. Nitrate removal in wetlands has usually been attributed to denitrification processes which in turn imply the production of greenhouse gases (CO{sub 2} and N{sub 2}O). Denitrification processes were studied in the Salburua wetland (northern Spain) by using undisturbed soil columns which were subsequently divided into three sections corresponding to A-, Bg- and B2g-soil horizons. Soil horizons were subjected to leaching with a 200 mg NO{sub 3}{sup -} L{sup -1} solution (rate: 90 mL day{sup -1}) for 125 days at two different temperatures (10 and 20 {sup o}C), using a new experimental design for leaching assays which enabled not only to evaluate leachate composition but also to measure gas emissions during the leaching process. Column leachate samples were analyzed for NO{sub 3}{sup -} concentration, NH{sub 4}{sup +} concentration, and dissolved organic carbon. Emissions of greenhouse gases (CO{sub 2} and N{sub 2}O) were determined in the undisturbed soil columns. The A horizon at 20 {sup o}C showed the highest rates of NO{sub 3}{sup -} removal (1.56 mg N-NO{sub 3}{sup -} kg{sup -1} DW soil day{sup -1}) and CO{sub 2} and N{sub 2}O production (5.89 mg CO{sub 2} kg{sup -1} DW soil day{sup -1} and 55.71 {mu}g N-N{sub 2}O kg{sup -1} DW soil day{sup -1}). For the Salburua wetland riparian soil, we estimated a potential nitrate removal capacity of 1012 kg N-NO{sub 3}{sup -} ha{sup -1} year{sup -1}, and potential greenhouse gas emissions of 5620 kg CO{sub 2} ha{sup -1} year{sup -1} and 240 kg N-N{sub 2}O ha{sup -1} year{sup -1}. - Research Highlights: {yields}A new experimental design is proposed for leaching assays to simulate nitrogen transformations in riparian wetland soil. {yields}Denitrification is the main process responsible for nitrate removal in the riparian zone of Salburua wetland. {yields

  8. Fate of linear alkylbenzene sulfonate in agricultural soil columns during inflow of surfactant pulses

    Science.gov (United States)

    Boluda-Botella, N.; León, V. M.; Cases, V.; Gomis, V.; Prats, D.

    2010-12-01

    The transport and reaction processes of linear alkylbenzene sulfonate (LAS) were characterised in columns of agricultural soil with a constant inflow of irrigation water. A pulse input of commercial LAS was performed with different mixtures of soil and sea sand (0/100%, 25/75% and 50/50%) and a continuous water flow of approximately 0.5 mL/min. LAS homologue retention was favoured at a higher soil rate, due mainly to higher clay and organic matter contents. C 10LAS and C 11LAS were less retained in soil columns, and were eluted faster and in higher proportion through soil columns than other homologues. C 12LAS and C 13LAS showed stronger interactions with soil due to their higher sorption capacity, and a lower proportion was eluted than the lightest homologues. In general, sorption of LAS was reversible and significant fractions were desorbed when the LAS input ceased and they were transported to deeper layers in the soil column, especially for short-chain homologues. Longer LAS homologues were eluted from soil columns, but required an elution of >10 pore-volumes. When there was biodegradation in the soil column, >25% of LAS could be removed, reducing percolation to deeper layers.

  9. Batch soil adsorption and column transport studies of 2,4-dinitroanisole (DNAN) in soils.

    Science.gov (United States)

    Arthur, Jennifer D; Mark, Noah W; Taylor, Susan; Šimunek, J; Brusseau, M L; Dontsova, Katerina M

    2017-03-01

    The explosive 2,4,6-trinitrotoluene (TNT) is currently a main ingredient in munitions; however the compound has failed to meet the new sensitivity requirements. The replacement compound being tested is 2,4-dinitroanisole (DNAN). DNAN is less sensitive to shock, high temperatures, and has good detonation characteristics. However, DNAN is more soluble than TNT, which can influence transport and fate behavior and thus bioavailability and human exposure potential. The objective of this study was to investigate the environmental fate and transport of DNAN in soil, with specific focus on sorption processes. Batch and column experiments were conducted using soils collected from military installations located across the United States. The soils were characterized for pH, electrical conductivity, specific surface area, cation exchange capacity, and organic carbon content. In the batch rate studies, change in DNAN concentration with time was evaluated using the first order equation, while adsorption isotherms were fitted using linear and Freundlich equations. Solution mass-loss rate coefficients ranged between 0.0002h(-1) and 0.0068h(-1). DNAN was strongly adsorbed by soils with linear adsorption coefficients ranging between 0.6 and 6.3Lg(-1), and Freundlich coefficients between 1.3 and 34mg(1)(-)(n)L(n)kg(-1). Both linear and Freundlich adsorption coefficients were positively correlated with the amount of organic carbon and cation exchange capacity of the soil, indicating that similar to TNT, organic matter and clay minerals may influence adsorption of DNAN. The results of the miscible-displacement column experiments confirmed the impact of sorption on retardation of DNAN during transport. It was also shown that under flow conditions DNAN transforms readily with formation of amino transformation products, 2-ANAN and 4-ANAN. The magnitudes of retardation and transformation observed in this study result in significant attenuation potential for DNAN, which would be anticipated

  10. Batch soil adsorption and column transport studies of 2,4-dinitroanisole (DNAN) in soils

    Science.gov (United States)

    Arthur, Jennifer D.; Mark, Noah W.; Taylor, Susan; Šimunek, J.; Brusseau, M. L.; Dontsova, Katerina M.

    2017-04-01

    The explosive 2,4,6-trinitrotoluene (TNT) is currently a main ingredient in munitions; however the compound has failed to meet the new sensitivity requirements. The replacement compound being tested is 2,4-dinitroanisole (DNAN). DNAN is less sensitive to shock, high temperatures, and has good detonation characteristics. However, DNAN is more soluble than TNT, which can influence transport and fate behavior and thus bioavailability and human exposure potential. The objective of this study was to investigate the environmental fate and transport of DNAN in soil, with specific focus on sorption processes. Batch and column experiments were conducted using soils collected from military installations located across the United States. The soils were characterized for pH, electrical conductivity, specific surface area, cation exchange capacity, and organic carbon content. In the batch rate studies, change in DNAN concentration with time was evaluated using the first order equation, while adsorption isotherms were fitted using linear and Freundlich equations. Solution mass-loss rate coefficients ranged between 0.0002 h- 1 and 0.0068 h- 1. DNAN was strongly adsorbed by soils with linear adsorption coefficients ranging between 0.6 and 6.3 L g- 1, and Freundlich coefficients between 1.3 and 34 mg1 - n Ln kg- 1. Both linear and Freundlich adsorption coefficients were positively correlated with the amount of organic carbon and cation exchange capacity of the soil, indicating that similar to TNT, organic matter and clay minerals may influence adsorption of DNAN. The results of the miscible-displacement column experiments confirmed the impact of sorption on retardation of DNAN during transport. It was also shown that under flow conditions DNAN transforms readily with formation of amino transformation products, 2-ANAN and 4-ANAN. The magnitudes of retardation and transformation observed in this study result in significant attenuation potential for DNAN, which would be anticipated to

  11. Generation of High Frequency Response in a Dynamically Loaded, Nonlinear Soil Column

    Energy Technology Data Exchange (ETDEWEB)

    Spears, Robert Edward [Idaho National Laboratory; Coleman, Justin Leigh [Idaho National Laboratory

    2015-08-01

    Detailed guidance on linear seismic analysis of soil columns is provided in “Seismic Analysis of Safety-Related Nuclear Structures and Commentary (ASCE 4, 1998),” which is currently under revision. A new Appendix in ASCE 4-2014 (draft) is being added to provide guidance for nonlinear time domain analysis which includes evaluation of soil columns. When performing linear analysis, a given soil column is typically evaluated with a linear, viscous damped constitutive model. When submitted to a sine wave motion, this constitutive model produces a smooth hysteresis loop. For nonlinear analysis, the soil column can be modelled with an appropriate nonlinear hysteretic soil model. For the model in this paper, the stiffness and energy absorption result from a defined post yielding shear stress versus shear strain curve. This curve is input with tabular data points. When submitted to a sine wave motion, this constitutive model produces a hysteresis loop that looks similar in shape to the input tabular data points on the sides with discontinuous, pointed ends. This paper compares linear and nonlinear soil column results. The results show that the nonlinear analysis produces additional high frequency response. The paper provides additional study to establish what portion of the high frequency response is due to numerical noise associated with the tabular input curve and what portion is accurately caused by the pointed ends of the hysteresis loop. Finally, the paper shows how the results are changed when a significant structural mass is added to the top of the soil column.

  12. Water flow induced transport of Pseudomonas fluorescens cells through soil columns as affected by inoculant treatment

    NARCIS (Netherlands)

    Hekman, W.E.; Heijnen, C.E.; Trevors, J.T.; Elsas, van J.D.

    1994-01-01

    Water flow induced transport of Pseudomonas fluorescens cells through soil columns was measured as affected by the inoculant treatment. Bacterial cells were introduced into the topsoil of columns, either encapsulated in alginate beads of different types or mixed with bentonite clay in concentrations

  13. Water flow induced transport of Pseudomonas fluorescens cells through soil columns as affected by inoculant treatment

    NARCIS (Netherlands)

    Hekman, W.E.; Heijnen, C.E.; Trevors, J.T.; Elsas, van J.D.

    1994-01-01

    Water flow induced transport of Pseudomonas fluorescens cells through soil columns was measured as affected by the inoculant treatment. Bacterial cells were introduced into the topsoil of columns, either encapsulated in alginate beads of different types or mixed with bentonite clay in concentrations

  14. Column displacement experiments to evaluate electrical conductivity effects on electromagnetic soil water sensing

    Science.gov (United States)

    Bulk electrical conductivity (EC) in superactive soils has been shown to strongly influence electromagnetic sensing of permittivity. However, these effects are dependent on soil water content and temperature as well as the pore water conductivity. We carried out isothermal column displacement experi...

  15. A New Rapid Determination Method of Soil Organic Carbon Adsorption Coefficients of Pesticides with Soil Column Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Soil column liquid chromatography (SCLC) was developed to determine soil organic carbon adsorption coefficients (Koc) for chemicals. The uptake by soil of pesticides from water can be conveniently calculated from the related breakthrough curves (BTC). The nine pesticides chosen for determination in this study are soluble ones, with their water solubility ranging from 62 mg/L to 2 mg/L. In comparing with existing methods of Koc, SCLC possesses rapid, online and accurate characteristics.

  16. Influence of soil structure on contaminant leaching from injected slurry

    DEFF Research Database (Denmark)

    Amin, M. G. Mostofa; Pedersen, Christina Østerballe; Forslund, Anita;

    2016-01-01

    macropore flow paths. The slurry constituents that ended up in or near the macropore flow paths of the intact soil were presumably washed out relatively quickly in the first event. For the last three events the intact soil leached fewer microorganisms than the disturbed soil due to the bypassing effect...... and persistence of nitrogen, microorganisms (bacteriophage, E. coli, and Enterococcus) and a group of steroid hormone (estrogens) were investigated after injection of swine slurry into either intact (structured) or disturbed (homogeneous repacked) soil. The slurry was injected into hexaplicate soil columns...... of water through the macropore flow path in the intact soil. Estrogen leached from the intact soil in the first event only, but for the disturbed soil it was detected in the leachates of last two events also. Leaching from the later events was attributed to higher colloid transport from the disturbed soils...

  17. 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.

  18. 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.

  19. Phosphorous and nitrogen changes in compost-amended schist soils in vineyards in the D.O. Priorat wine-producing area (NE Spain)

    OpenAIRE

    2010-01-01

    The impact, on nitrogen and phosphorous dynamics, of applying compost at different rates was investigated in soils developed on schist in new terraced vineyards (NTV) and in undisturbed areas (NC). Repacked soil columns amended with 0 (control), 50 t ha –1 (T1) and 100 t ha–1 (T2) of compost were studied under laboratory conditions simulating both situations. The columns were maintained for 1 year, during which time a total of 300 mm of simulated rainfall was applied in ten 30 mm applications...

  20. Experimental and modelling investigations of tracer transport in variably saturated agricultural soil of Thailand: Column study

    Directory of Open Access Journals (Sweden)

    Tulaya Masipan

    2016-03-01

    Full Text Available Tracer (Bromide movement through the unsaturated agricultural soil was investigated in soil columns. Two tracer column experiments, with a diameter of 7 cm and a depth of 25 cm, were vertically homogeneous packed with sandy loam and then carried out to investigate bromide (Br− transport under different water contents (at steady flow condition. One soil column (Column 1 represents the unsaturated agricultural soil in dry season (with water content ranging from 0.23 to 0.26 and the other (Column 2 represents the soil in wet season (water content from 0.24 to 0.35. Bromide samples were periodically collected by vacuum tubes inserted at 6.25 cm equally spaced intervals (e.g., 6.25, 12.5, 18.75 and 25 cm along the length of the column and the effluent collected at the end of the column. The observed breakthrough curves (BTCs of bromide in both columns represented a relative smooth and sigmodal curves at different distances (sampling ports. Dispersivity (α, cm for sandy loam at different locations was numerically estimated by curve fitting the experimental data with HYDRUS-1D. The α can be well described by the convection–dispersion equation and these values derived from Column 1 (ranging from 0.37 to 0.98 cm are more than those from Column 2 (0.25–0.59. Moreover, the α in both columns increases with the travel distance due to the scale-dependent effect. Furthermore, the α values were plotted on a log–log scale against travel distances and they yield empirical power law relationships with an excellent correlation (α = 0.102 (L0.697, R2 = 0.999 and α = 0.086 (L0.579, R2 = 0.963 for Column 1 and 2, respectively.

  1. Ureic nitrogen transformation in multi-layer soil columns treated with urease and nitrification inhibitors.

    Science.gov (United States)

    Giovannini, Camilla; Garcia-Mina, Josè M; Ciavatta, Claudio; Marzadori, Claudio

    2009-06-10

    The use of N-(n-butyl)thiophosphoric triamide (NBPT), as a urease inhibitor, is one of the most successful strategies utilized to increase the efficiency of urea-based fertilization. To date, NBPT has been added to the soil incorporated in fertilizers containing either urea or the inhibitor at a fixed percentage on the urea weight. The possibility of using NBPT physically separated from urea-based fertilizers could make its use more flexible. In particular, a granulated product containing NBPT could be utilized in soils treated with different urea-based fertilizers including livestock urine, the amount depending on soil characteristics and/or the urea source (e.g., mineral fertilizer, organo-mineral fertilizer, or animal slurry). In this study, a multilayer soil column device was used to investigate the influence of an experimental granular product (RV) containing NBPT and a garlic extract, combining the ability to protect NBPT by oxidation and nitrification inhibition activity, on (a) spatial variability of soil urease and nitrification activities and (b) timing of urea hydrolysis and mineral-N form accumulation (NO(2)(-), NO(3)(-), NH(4)(+)) in soil treated with urea. The results clearly demonstrated that RV can, effectively, inhibit the soil urease activity along the soil column profile up to 8-10 cm soil layer depth and that the inhibition power of RV was dependent on time and soil depth. However, nitrification activity is not significantly influenced by RV addition. In addition, the soil N transformations were clearly affected by RV; in fact, RV retarded urea hydrolysis and reduced the accumulation of NH(4)(+)-N and NO(2)(-)-N ions along the soil profile. The RV product was demonstrated to be an innovative additive able to modify some key ureic N trasformation processes correlated with the efficiency of the urea-based fertilization, in a soil column higher than 10 cm.

  2. Calculating carbon mass balance from unsaturated soil columns treated with CaSO₄₋minerals: test of soil carbon sequestration.

    Science.gov (United States)

    Han, Young-Soo; Tokunaga, Tetsu K

    2014-12-01

    Renewed interest in managing C balance in soils is motivated by increasing atmospheric concentrations of CO2 and consequent climate change. Here, experiments were conducted in soil columns to determine C mass balances with and without addition of CaSO4-minerals (anhydrite and gypsum), which were hypothesized to promote soil organic carbon (SOC) retention and soil inorganic carbon (SIC) precipitation as calcite under slightly alkaline conditions. Changes in C contents in three phases (gas, liquid and solid) were measured in unsaturated soil columns tested for one year and comprehensive C mass balances were determined. The tested soil columns had no C inputs, and only C utilization by microbial activity and C transformations were assumed in the C chemistry. The measurements showed that changes in C inventories occurred through two processes, SOC loss and SIC gain. However, the measured SOC losses in the treated columns were lower than their corresponding control columns, indicating that the amendments promoted SOC retention. The SOC losses resulted mostly from microbial respiration and loss of CO2 to the atmosphere rather than from chemical leaching. Microbial oxidation of SOC appears to have been suppressed by increased Ca(2+) and SO4(2)(-) from dissolution of CaSO4 minerals. For the conditions tested, SIC accumulation per m(2) soil area under CaSO4-treatment ranged from 130 to 260 g C m(-1) infiltrated water (20-120 g C m(-1) infiltrated water as net C benefit). These results demonstrate the potential for increasing C sequestration in slightly alkaline soils via CaSO4-treatment.

  3. The Impact of Organo-Mineral Complexation on Mineral Weathering in the Soil Zone: Column Experiment

    Science.gov (United States)

    Tan, F.; Dever, S.; Yoo, K.; Imhoff, P. T.; Michael, H. A.

    2015-12-01

    While it is well known that organo-mineral complexes can protect organic matter (OM) from degradation, its impact on soil mineral weathering is not clear. Strong evidence has shown that the adsorption of OM to mineral surface accelerates the dissolution of some minerals, but these observations are limited to bench-scale experiments that focus on specific OM and minerals. In this study, soil samples prepared from an undisturbed forest site were used to determine mineral weathering rates under differing OM sorption on minerals. Soil samples from two depths, 0-6cm and 84-100cm, were chosen to represent different soil OM content and soil mineralogy. Soil OM was removed stepwise by heating samples to 350℃ for different durations (0-6cm: 100% removed, ~50% removed, and no removal; 84-100cm: 100% removed and no removal). Pretreated soil samples were subjected to flow-through, saturated column experiments using 0.01M LiCl and 5%CO2/95%air gas saturated (pH = 4.5) influent solution. Each column treatment was run in duplicate under a constant flow rate (Darcy velocity ≈ 8cm/hr). All columns reached a steady state after 600~700 pore volumes at which effluent pH, dissolved organic carbon (DOC) and element concentrations were constant. At the 95% significance level, the DOC from OM-present columns was significantly higher, as expected. Correspondingly, effluent pH was lower in higher OM content columns. The chemical denudation rates were calculated from the effluent concentrations of the elements of interest. For the soil columns from both depths, silicon (Si) leaching rate showed that dissolution of silicate minerals was 2-3 times higher in OM-removed columns, suggesting that organo-mineral complexes suppress mineral dissolution. The N2-BET specific surface area (SSA) measurement also showed that the removal of OM increased SSA, which supported the idea that OM adsorption had decreased mineral exposure and thus decreased mineral dissolution. The leaching rates of some

  4. Storage duration effect on deformation recovery of repacked alginates

    Directory of Open Access Journals (Sweden)

    Siti Sunarintyas

    2009-09-01

    Full Text Available Background: Manufacturers supply alginate impression materials as a powder that is packaged in bulk and in individual container. Some Indonesian dental suppliers often repackage the bulk alginate into individual plastic packages which are not tied tightly and stored in the display room without air conditioner. It is known that critical factors to the shelf life of alginate includer avoidance of moisture contamination which may lead to premature setting of the alginate and avoidance of high temperature which may cause depolymerization of the alginate. Purpose: The aim of this study was to determine storage duration effect of repacked alginates on deformation recovery. Methods: Two brands of alginates (Tulip®TU, and Aroma Fine DF III®AF were repacked into 120 plastic containers. The samples were stored in room condition (temperature 29° C ± 1° C, relative humidity 60% ± 10% for 1, 2, 3, 4 and 5 weeks. The alginates setting time and recovery from deformation were measured according to the ANSI/ADA specification number 18 (ISO 1563. result: The results revealed that there was decreased setting time during 5 weeks but there was slight decreased in deformation recovery after 3 weeks storage. The ANOVA showed there was no significant difference of alginates deformation recovery among the storage times (p > 0.05. Conclusion: Storage duration of repacked alginates in plastic containers during 5 weeks in room condition do not influence the alginate deformation recovery.

  5. Phosphorus leaching from cow manure patches on soil columns

    NARCIS (Netherlands)

    Chardon, W.J.; Aalderink, G.H.; Salm, van der C.

    2007-01-01

    The loss of P in overland flow or leachate from manure patches can impair surface water quality. We studied leaching of P from 10-cmhigh lysimeters filled with intact grassland soil or with acid-washed sand. A manure patch was created on two grassland and two sandfilled lysimeters, and an additional

  6. Unsaturated hydraulic conductivity of sandy soil columns packed to different bulk densities and water uptake by plantroots

    NARCIS (Netherlands)

    Rossi-Pisa, P.

    1978-01-01

    This paper describes a laboratory metbod used to determine both the soil moisture retention curve and the unsaturated hydraulic conductivity in soil columns under transient flow conditions during evaporation.

  7. Liquefaction mitigation in silty soils using composite stone columns and dynamic compaction

    Institute of Scientific and Technical Information of China (English)

    T.Shenthan; R.Nashed; S.Thevanayagam; G. R. Martin

    2004-01-01

    The objective of this study is to develop an analytical methodology to evaluate the effectiveness ofvibro stone column (S.C.) and dynamic compaction (D.C.) techniques supplemented with wick drains to densify and mitigate liquefaction in saturated sands and non-plastic silty soils. It includes the following: (i) develop numerical models to simulate and analyze soil densification during S.C. installation and D.C. process, and (ii) identify parameters controlling post-improvement soil density in both cases, and (iii) develop design guidelines for densification of silty soils using the above techniques. An analytical procedure was developed and used to simulate soil response during S.C. and D.C. installations, and the results were compared with available case history data. Important construction design parameters and soil properties that affect the effectiveness of these techniques, and construction design choices suitable for sands and non-plastic silty soils were identified.The methodology is expected to advance the use of S.C. and D.C. in silty soils reducing the reliance on expensive field trials as a design tool. Thc ultimate outcome of this research will be design charts and design guidelines for using composite stone columns and composite dynamic compaction techniques in liquefaction mitigation of saturated silty soils.

  8. Bacteria transport and retention in intact calcareous soil columns under saturated flow conditions

    Directory of Open Access Journals (Sweden)

    Farrokhian Firouzi Ahmad

    2015-06-01

    Full Text Available Study of bacterial transport and retention in soil is important for various environmental applications such as groundwater contamination and bioremediation of soil and water. The main objective of this research was to quantitatively assess bacterial transport and deposition under saturated conditions in calcareous soil. A series of leaching experiments was conducted on two undisturbed soil columns. Breakthrough curves of Pseudomonas fluorescens and Cl were measured. After the leaching experiment, spatial distribution of bacteria retention in the soil columns was determined. The HYDRUS-1D one- and two-site kinetic models were used to predict the transport and deposition of bacteria in soil. The results indicated that the two-site model fits the observed data better than one-site kinetic model. Bacteria interaction with the soil of kinetic site 1 revealed relatively fast attachment and slow detachment, whereas attachment to and detachment of bacteria from kinetic site 2 was fast. Fast attachment and slow detachment of site 1 can be attributed to soil calcium carbonate that has favorable attachment sites for bacteria. The detachment rate was less than 0.02 of the attachment rate, indicating irreversible attachment of bacteria. High reduction rate of bacteria was also attributed to soil calcium carbonate.

  9. Effect of Coated Urea with Humic-Calcium on Transformation of Nitrogen in Coastal Sandy Soil: A Soil Column Method

    Directory of Open Access Journals (Sweden)

    Sulakhudin

    2010-01-01

    Full Text Available Effect of Coated Urea with Humic-Calcium on Transformation of Nitrogen in Coastal Sandy Soil: A Soil ColumnMethod (Sulakhudin, A Syukur, D Shiddieq and T Yuwono: In coastal sandy soil, mainly nitrogen losses due toleaching resulted to low fertilizer efficiency. Slow-release N fertilizers are proposed to minimize these losses, andhumic-calcium coated urea has been examined. A soil column method was used to compare the effects of coated ureawith humic-calcium on transformation and leaching loss of N in coastal sandy soil. The experiment aid to compare twokinds sources of humic substances (cow manure and peat which mixed with calcium as coated urea on transformation,vertical distribution and leaching N in coastal sandy soil. The concentration of humic-calcium coated urea i.e.1%, 5%and 10% based on their weight. The results showed that urea coated with humic-calcium from cow manure (UCHMand humic-calcium from peat (UCHP increased the N total and available N in the soil and decreased leaching loss ofN from the soil column. Compared to UCHP, UCHM in all concentration showed N-nitrate higher than N-ammonium onincubation length 2, 4 and 6 weeks. The N leached from a costal sandy soil with application coated urea with UCHMranged from 21.18% to 23.72% of the total N added as fertilizer, for coated urea with UCHP they ranged between21.44% and 23.25%, whereas for urea (control reached 29.48%. Leaching losses of mineral N were lower when ureacoated with UCHM compared to urea coated with UCHP or urea fertilizer. The study concluded that the UCHM isbetter than UCHP in decreasing N leached from coastal sandy soil

  10. Simplified method for predicating consolidation settlement of soft ground improved by floating soil-cement column

    Institute of Scientific and Technical Information of China (English)

    龚晓南; 田效军; 胡文韬

    2015-01-01

    A simplified method is presented for predicting consolidation settlement of soft ground improved by floating soil−cement column on the basis of double soil-layer consolidation theory. Combining the axisymmetric consolidation model and equal strain assumption, the governing equation was derived for the consolidation of clayey subsoil reinforced by soil−cement column. By modifying the boundary condition of the interface between the improved layer and underlying layer on seepage and pore-water pressure, the analytical solution of consolidation of soft ground improved by floating soil−cement column was developed under depth-dependent ramp load. The results of the parameter analysis of consolidation behavior show that the consolidation rate is closely related with the depth replacement ratio by the column and the permeability of upper layer. The influence of column−soil constrained modulus ratio and radius ratio of the influence zone to the column on consolidation is also affected by depth replacement ratio. The column−soil total stress ratio increases with time and approaches the final value accompanied with the dissipation of excess pore water pressure.

  11. Use of the Time Domain Reflectometry to evaluate the nitrate distribution in fertirrigated soils columns

    Directory of Open Access Journals (Sweden)

    Rubens Alves de Oliveira

    2009-12-01

    Full Text Available The monitoring of spatial and temporal variation of the soil water content (θ, of the soil bulk electric conductivity (CEs, of the soil solution electric conductivity (CEss and of the ion concentration (Ci enables to estimate the water loss by deep percolation and evapotranspiration, to determine the areas of nutrients extraction by plants and the possible nutrients loss by leaching. The of objective this work was to evaluate, using the TDR technique, the nitrate distribution in Typic Quartzipsamment (RQ and Oxisol (LV soil columns fertirrigated with calcium nitrate. Nitrate fertirrigations were accomplished in the columns, and the soil water content (θ and the soil bulk electric conductivity (CEs obtained with TDR. The nitrate concentration was estimated using the values of θ and of CEs. In the RQ soil, the nitrate reached 30, 21 e 12 cm when the fertirrigations were done at the beginning, at the middle and at the end of the irrigation period, respectively. In the LV soil, independently of the moment of the fertirrigation, the nitrate was retained in the layer from 0 to 12 cm deep.

  12. Transport of Cryptosporidium parvum oocysts in soil columns following applications of raw and separated liquid slurry

    DEFF Research Database (Denmark)

    Petersen, Heidi Huus; Enemark, Heidi L.; Olsen, Annette;

    2012-01-01

    . Among leachate samples containing oocysts, 44/72 samples yielded viable oocysts as determined by a dye permeability assay (DAPI/PI) with the majority (41%) of viable oocysts found in leachate from soil columns with added liquid slurry. The number of viable oocysts was positively correlated (r=0...

  13. Effect of nitrification on movement of trace metals in soil columns

    Energy Technology Data Exchange (ETDEWEB)

    Chang, F.; Broadbent, F.E.

    1980-01-01

    Soil column experiments were conducted with sludge-treated and untreated samples of two soils, Omni silty clay and Delhi loamy sand, to determine whether protons generated during the nitrification process would affect the mobility of the trace metals Cd, Cr, Cu, Mn, Pb, and Zn. Columns 5 cm x 100 cm were leached bi- or tri-weekly with 7.5-cm applications of solutions of CaCl/sub 2/, NH/sub 4/Cl, or KCl. Trace metals in effluents from the columns were analyzed after each application of leaching solution. After 11 appications over a period of several months-the columns were sectioned and the vertical distribution of 2N NCl-extractable metals determined. Average concentrations of metals in column effluents were well below 1 ppM in all cases except Zn eluted from untreated Delhi loamy sand where 20 mM NH/sub 4/Cl or KCl leaching solutions produced effluent concentrations slightly above 1 ppM. There was evidence of nitrification affecting movement of several of the metals, particularly in the cases of Mn, Zn, Cu, and Cd in the untreated Delhi soil. The presence of sludge had a pronounced stabilizing influence of Cd and Zn, and to a lesser degree on other metals, probably as a result of organo-metal complexes. Much of the input labeled NH/sub 4/-N was denitrified, as shown by recoveries of N ranging from 14 to 20% in the Omni soil and 40 to 78% in the Delhi soil. Proton generation during denitrification. It was concluded that nitrification had relatively little effect on metal mobility under the conditions of the experiment.

  14. 21 CFR 201.122 - Drugs for processing, repacking, or manufacturing.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Drugs for processing, repacking, or manufacturing... for processing, repacking, or manufacturing. A drug in a bulk package, except tablets, capsules, or... manufacturing, processing, or repacking”; and if in substantially all dosage forms in which it may be dispensed...

  15. Study of the transport of cadusafos in two tropical undisturbed soil columns

    Science.gov (United States)

    Dionisio Fernandez-Bayo, Jesus; Crevoisier, David; Saison, Carine; Geniez, Chantal; Huttel, Olivier; Samouelian, Anatja; Voltz, Marc

    2013-04-01

    The use of pesticides to control agriculture pests is a common practice on most tropical plantations whose vulnerability to pesticide pollution is very important due to the frequent heavy rains that wash pesticides from target areas. Tropical volcanic soils have been scarcely investigated in this sense and monitoring the dynamic of pesticide at column scale is of great interest for a better understanding at catchment scale and risk modelling. The objective was to study and model the transport of cadusafos (CDS) in two undisturbed soil columns from a nitisol and an andosol, representative of the major soils in agricultural areas of the FWI. Undisturbed soil columns from andosol (sandy-loam soil) and nitisol (clay soil) from Guadeloupe Island were spiked with 14C-CDS along with 10 g of granulate Rugby®. To each soil column, 10 rain events of different intensities (20 and 40 mm/h during 4 and 2 hours, respectively) were applied with 4-7 days delay between two subsequent rain events. For the nitisol columns, the cumulated rain was halved (by decreasing duration of each rain event) since these soils occur in drier areas of Guadeloupe and because the imposed rain intensities led to the accumulation of water at the surface of the column. At the end of the leaching experiment the extractable and non-extractable remaining pesticide residues were determined along the soil profile. The andosol presented a very high permeability attributed to the preferential flow expected in this type of soil with high macroporosity due to the allophane materials. The maximum concentration of CDS was attained during the first rainfall event while the cumulated infiltrated volume of water was much less than the pore volume of the column soil. The peak concentration levels of CDS were almost constant during the first 5 rain events and they decreased during the subsequent rain events, probably due to degradation and/or ageing processes of CDS. The nitisol showed lower permeability reflected in

  16. Leaching and Transformation of Nitrogen Fertilizers in Soil After Application of N with Irrigation: A Soil Column Method

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A soil column method was used to compare the effect of drip fertigation (the application of fertilizer through drip irrigation systems, DFI) on the leaching loss and transformation of urea-N in soil with that of surface fertilization combined with flood irrigation (SFI), and to study the leaching loss and transformation of three kinds of nitrogen fertilizers (nitrate fertilizer, ammonium fertilizer, and urea fertilizer) in two contrasting soils after the fertigation. In comparison to SFI,DFI decreased leaching loss of urea-N from the soil and increased the mineral N (NH4+-N + NO3--N) in the soil. The N leached from a clay loam soil ranged from 5.7% to 9.6% of the total N added as fertilizer, whereas for a sandy loam soil they ranged between 16.2% and 30.4%. Leaching losses of mineral N were higher when nitrate fertilizer was used compared to urea or ammonium fertilizer. Compared to the control (without urea addition), on the first day when soils were fertigated with urea, there were increases in NH4+-N in the soils. This confirmed the rapid hydrolysis of urea in soil during fertigation. NH4+-N in soils reached a peak about 5 days after fertigation, and due to nitrification it began to decrease at day 10. After applying NH4+-N fertilizer and urea and during the incubation period, the mineral nitrogen in the soil decreased. This may be related to the occurrence of NH4+-N fixation or volatilization in the soil during the fertigation process.

  17. Multi-process herbicide transport in structured soil columns: experiments and model analysis.

    Science.gov (United States)

    Köhne, J Maximilian; Köhne, Sigrid; Simůnek, Jirka

    2006-05-01

    Model predictions of pesticide transport in structured soils are complicated by multiple processes acting concurrently. In this study, the hydraulic, physical, and chemical nonequilibrium (HNE, PNE, and CNE, respectively) processes governing herbicide transport under variably saturated flow conditions were studied. Bromide (Br-), isoproturon (IPU, 3-(4-isoprpylphenyl)-1,1-dimethylurea) and terbuthylazine (TER, N2-tert-butyl-6-chloro-N4-ethyl-1,3,5-triazine-2,4-diamine) were applied to two soil columns. An aggregated Ap soil column and a macroporous, aggregated Ah soil column were irrigated at a rate of 1 cm h(-1) for 3 h. Two more irrigations at the same rate and duration followed in weekly intervals. Nonlinear (Freundlich) equilibrium and two-site kinetic sorption parameters were determined for IPU and TER using batch experiments. The observed water flow and Br- transport were inversely simulated using mobile-immobile (MIM), dual-permeability (DPM), and combined triple-porosity (DP-MIM) numerical models implemented in HYDRUS-1D, with improving correspondence between empirical data and model results. Using the estimated HNE and PNE parameters together with batch-test derived equilibrium sorption parameters, the preferential breakthrough of the weakly adsorbed IPU in the Ah soil could be reasonably well predicted with the DPM approach, whereas leaching of the strongly adsorbed TER was predicted less well. The transport of IPU and TER through the aggregated Ap soil could be described consistently only when HNE, PNE, and CNE were simultaneously accounted for using the DPM. Inverse parameter estimation suggested that two-site kinetic sorption in inter-aggregate flow paths was reduced as compared to within aggregates, and that large values for the first-order degradation rate were an artifact caused by irreversible sorption. Overall, our results should be helpful to enhance the understanding and modeling of multi-process pesticide transport through structured soils

  18. Strengthening and Stabilization of the Weak Water Saturated Soils Using Stone Columns

    Directory of Open Access Journals (Sweden)

    Sinyakov Leonid

    2016-01-01

    Full Text Available The article considers innovative modern materials and structures for strengthening of weak soils. In this paper describes a method of strengthening of weak saturated soils using stone columns. The method of calculating the physical-mechanical characteristics of reinforced soil mass is presented. Two approaches to determining the stress-strain state and timeframe of consolidation of strengthened soil foundation using the finite element technique in two-dimensional formulation are proposed. The first one approach it is a modeling of reinforced soil mass, where each pile is represented as a separate 2D stripe. The second approach is to the simulation of the strengthened mass the equivalent composite block with improved physical-mechanical characteristics. The use of the equivalent composite block can significantly reduce the time spent on the preparation of a design scheme. The results of calculations were compared. They show the allowable divergence of results of calculation by two methods were presented, and the efficiency of the strengthening of weak water saturated soils by stone column is proved.

  19. Dynamic Characteristics of Saturated Silty Soil Ground Treated by Stone Column Composite Foundation

    Directory of Open Access Journals (Sweden)

    Yongxiang Zhan

    2014-01-01

    Full Text Available A shaking table model test was carried out to develop an understanding of the performance improvement of saturated silty soil ground using stone column composite foundation as reinforcement. It is found that at less than 0.161 g loading acceleration, soil between piles has not yet been liquefied, the response acceleration scarcely enlarges, and the shear displacement almost does not appear in silty soil. At 0.252 g loading acceleration, as a result of liquefaction of soil between piles, the response acceleration increases rapidly and reaches its peak, and the shear displacement of silty soil increases significantly. At 0.325 g loading acceleration, the integral rigidity of foundation decreases greatly, which reduces its capability of vibration transmission and result in the response acceleration amplification coefficient is less than that at the former loading acceleration, but the shear displacement of silty soil further increases. The stone column composite foundation can greatly reduce both the shear displacement and the settlement of ground compared with untreated foundation. Under the condition of 7-degree seismic fortification, the design meets seismic resistance requirements.

  20. Linking Water Table Dynamics to Carbon Cycling in Artificial Soil Column Incubations

    Science.gov (United States)

    Geertje, Pronk; Adrian, Mellage; Tatjana, Milojevic; Fereidoun, Rezanezhad; Cappellen Philippe, Van

    2016-04-01

    The biogeochemistry of wetlands soils is closely tied to their hydrology. Water table fluctuations that cause flooding and drying of these systems may lead to enhanced degradation of organic matter and release of greenhouse gasses (e.g. CO2, CH4) to the atmosphere. However, predicting the influence of water table fluctuations on the biogeochemical functioning of soils requires an understanding of the interactions of soil hydrology with biogeochemical and microbial processes. To determine the effects of water table dynamics on carbon cycling, we are carrying out state-of-the-art automated soil column experiments with fully integrated monitoring of hydro-bio-geophysical process variables under both constant and oscillating water table conditions. An artificial, homogeneous mixture consisting of minerals and organic matter is used to provide a well-defined starting material. The artificial soils are composed of quartz sand, montmorillonite, goethite and humus from a forested riparian zone, from which we also extracted the microbial inoculum added to the soil mixture. The artificial soils are packed into 60 cm high, 7.5 cm wide columns. In the currently ongoing experiment, three replicate columns are incubated while keeping the water table constant water at mid-depth, while another three columns alternate between drained and saturated conditions. Micro-sensors installed at different depths below the soil surface record time-series redox potentials (Eh) varying between oxidizing (~+700 mV) and reducing (~-200 mV) conditions. Continuous O2 levels throughout the soil columns are monitored using high-resolution, luminescence-based, Multi Fiber Optode (MuFO) microsensors. Pore waters are collected periodically with MicroRhizon samplers from different depths, and analyzed for pH, EC, dissolved inorganic and organic carbon and ion/cation compositions. These measurements allow us to track the changes in pore water geochemistry and relate them to differences in carbon cycling

  1. Implications of soil mixing for NAPL source zone remediation: Column studies and modeling of field-scale systems

    Science.gov (United States)

    Olson, Mitchell R.; Sale, Tom C.

    2015-06-01

    Soil remediation is often inhibited by subsurface heterogeneity, which constrains contaminant/reagent contact. Use of soil mixing techniques for reagent delivery provides a means to overcome contaminant/reagent contact limitations. Furthermore, soil mixing reduces the permeability of treated soils, thus extending the time for reactions to proceed. This paper describes research conducted to evaluate implications of soil mixing on remediation of non-aqueous phase liquid (NAPL) source zones. The research consisted of column studies and subsequent modeling of field-scale systems. For column studies, clean influent water was flushed through columns containing homogenized soils, granular zero valent iron (ZVI), and trichloroethene (TCE) NAPL. Within the columns, NAPL depletion occurred due to dissolution, followed by either column-effluent discharge or ZVI-mediated degradation. Complete removal of TCE NAPL from the columns occurred in 6-8 pore volumes of flow. However, most of the TCE (> 96%) was discharged in the column effluent; less than 4% of TCE was degraded. The low fraction of TCE degraded is attributed to the short hydraulic residence time ( 10 m) and reducing permeability by one-or-more orders of magnitude, the residence time could be greatly extended, potentially for periods of years to decades. Model output indicates that the fraction of TCE degraded can be increased to > 99.9%, given typical post-mixing soil permeability values. These results suggest that remediation performance can be greatly enhanced by combining contaminant degradation with an extended residence time.

  2. Using Artificial Soil and Dry-Column Flash Chromatography to Simulate Organic Substance Leaching Process: A Colorful Environmental Chemistry Experiment

    Science.gov (United States)

    de Avellar, Isa G. J.; Cotta, Tais A. P. G.; Neder, Amarilis de V. Finageiv

    2012-01-01

    Soil is an important and complex environmental compartment and soil contamination contributes to the pollution of aquifers and other water basins. A simple and low-cost experiment is described in which the mobility of three organic compounds in an artificial soil is examined using dry-column flash chromatography. The compounds were applied on top…

  3. 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...... a red‐yellow soil from Okinawa, Japan. Different concentrations of suspended‐soil colloids (with diameter ....21 mm) sands. The transport and retention of colloids were studied by analyzing colloid effluent breakthrough curves (BTCs), particle size distribution in the effluent, and colloid deposition profiles within the column. The results showed a significant influence of flow velocity: Low flow velocity...

  4. Assessment of existing roadside swales with engineered filter soil: II. Treatment efficiency and in situ mobilization in soil columns.

    Science.gov (United States)

    Ingvertsen, Simon T; Cederkvist, Karin; Jensen, Marina B; Magid, Jakob

    2012-01-01

    Use of roadside infiltration systems using engineered filter soil for optimized treatment has been common practice in Germany for decades, but little documentation is available regarding their long-term treatment performance. Here we present the results of laboratory leaching experiments with intact soil columns (15 cm i.d., 25-30 cm length) collected from two German roadside infiltration swales constructed in 1997. The columns were irrigated with synthetic solutions of unpolluted or polluted (dissolved heavy metals and fine suspended solids) road runoff, as well as a soluble nonreactive tracer (bromide) and a dye (brilliant blue). The experiments were performed at two irrigation rates corresponding to catchment rainfall intensities of approximately 5.1 and 34 mm/h. The bromide curves indicated that preferential flow was more pronounced at high irrigation rates, which was supported by the flow patterns revealed in the dye tracing experiment. Nonetheless, the soils seemed to be capable of retaining most of the dissolved heavy metals from the polluted road runoff at both low and high irrigation rates, except for Cr, which appears to pass through the soil as chromate. Fluorescent microspheres (diameter = 5 μm) used as surrogates for fine suspended solids were efficiently retained by the soils (>99%). However, despite promising treatment abilities, internal mobilization of heavy metals and P from the soil was observed, resulting in potentially critical effluent concentrations of Cu, Zn, and Pb. This is mainly ascribed to high concentrations of in situ mobilized dissolved organic carbon (DOC). Suggestions are provided for possible improvements and further research to minimize DOC mobilization in engineered filter soils.

  5. Influence of plant roots on electrical resistivity measurements of cultivated soil columns

    Science.gov (United States)

    Maloteau, Sophie; Blanchy, Guillaume; Javaux, Mathieu; Garré, Sarah

    2016-04-01

    Electrical resistivity methods have been widely used for the last 40 years in many fields: groundwater investigation, soil and water pollution, engineering application for subsurface surveys, etc. Many factors can influence the electrical resistivity of a media, and thus influence the ERT measurements. Among those factors, it is known that plant roots affect bulk electrical resistivity. However, this impact is not yet well understood. The goals of this experiment are to quantify the effect of plant roots on electrical resistivity of the soil subsurface and to map a plant roots system in space and time with ERT technique in a soil column. For this research, it is assumed that roots system affect the electrical properties of the rhizosphere. Indeed the root activity (by transporting ions, releasing exudates, changing the soil structure,…) will modify the rhizosphere electrical conductivity (Lobet G. et al, 2013). This experiment is included in a bigger research project about the influence of roots system on geophysics measurements. Measurements are made on cylinders of 45 cm high and a diameter of 20 cm, filled with saturated loam on which seeds of Brachypodium distachyon (L.) Beauv. are sowed. Columns are equipped with electrodes, TDR probes and temperature sensors. Experiments are conducted at Gembloux Agro-Bio Tech, in a growing chamber with controlled conditions: temperature of the air is fixed to 20° C, photoperiod is equal to 14 hours, photosynthetically active radiation is equal to 200 μmol m-2s-1, and air relative humidity is fixed to 80 %. Columns are fully saturated the first day of the measurements duration then no more irrigation is done till the end of the experiment. The poster will report the first results analysis of the electrical resistivity distribution in the soil columns through space and time. These results will be discussed according to the plant development and other controlled factors. Water content of the soil will also be detailed

  6. Surface water seal application to minimize volatilization loss of methyl isothiocyanate from soil columns.

    Science.gov (United States)

    Simpson, Catherine R; Nelson, Shad D; Stratmann, Jerry E; Ajwa, Husein A

    2010-06-01

    Metam-sodium (MS, sodium methyldithiocarbamate) has been identified as a promising alternative chemical to replace methyl bromide (MeBr) in soil preplant fumigation. One degradation product of MS in soil is the volatile gas methyl isothiocyanate (MITC) which controls soilborne pests. Inconsistent results associated with MS usage indicate that there is a need to determine cultural practices that increase pest control efficacy. Sealing the soil surface with water after MS application may be a sound method to reduce volatilization loss of MITC from soils and increase the contact time necessary for MITC to control pests. The objective of this research was to develop a preliminary soil surface water application amount that would potentially inhibit the off-gassing rate of MITC. Off-gassing rate was consistently reduced with increasing water seal application. The application of a 2.5-3.8 cm water seal provided significantly lower (71-74% reduction in MITC volatilization) total fumigant loss compared with no water seal. The most favorable reduction in MITC off-gassing was observed in the 2.5 cm water seal. This suggests that volatilization of MITC-generating compounds can be highly suppressed using adequate surface irrigation following chemical application in this soil type (sandy clay loam), based on preliminary bench-scale soil column studies. .

  7. Modeling Cadmium Transport in Neutral and Alkaline Soil Columns at Various Depths

    Institute of Scientific and Technical Information of China (English)

    QI Zhi-Ming; FENG Shao-Yuan; M.J.HELMERS

    2012-01-01

    Human health has been potentially threatened by cadmium (Cd) contained in sewage irrigation water.Previous studies of Cd transport in soils were mainly conducted using small soil cores with pH values less than 6.The objectives of this study were to determine the parameters of the convection-dispersion equation (CDE) for Cd transport in relatively larger columns with neutral and alkaline soils,and to investigate the parameters' variability with depth.The soil columns were 50 cm in length and 12.5 cm in diameter.Ceramic suction lysimeters were buried at depths of 2.5,7.5,17.5,27.5,and 37.5 cm to abstract soil solution.Cd concentration in the soil solution samples were subsequently analyzed to obtain breakthrough curves (BTCs).Equilibrium and nonequilibrium models in CXTFIT program were used to estimate parameters of the CDE.The results suggested that both equilibrium and non-equilibrium models performed well in modeling Cd transport.The hydrodynamic dispersion coefficient (D) ranged from 0.18 to 10.70 cm2 h-1,showing large differences among different depths.The retardation factor (Rd) ranged from 25.4 to 54.7 and the standard deviation of Rd value was lower than 30% of the mean value.Precipitation coefficient (Rp) decreased consistently with increasing depth,varying from 1.000 × 10-10 to 0.661 h-1.Sensitivity tests showed that D was less sensitive than Rd.These results would be helpful in understanding the transport and retention of Cd in non-acidic soils.

  8. Effects of the Length of Jet Grouted Columns and Soil Profile on the Settlement of Shallow Foundations

    Directory of Open Access Journals (Sweden)

    Zaheer Ahmed Almani

    2012-07-01

    Full Text Available In this paper, the effect of length of jet grouted columns and varying soil profile under shallow foundations of buildings constructed on the liquefiable ground was studied. The isolated shallow footing pad which supports a typical simple frame structure was constructed on the liquefiable ground. This ground was reinforced with jet grouted column rows under the shallow foundations of structure. The system was modeled as plane-strain using the FLAC 2D (Fast Lagrangian Analysis of Continua dynamic modelling and analysis code. This case focuses on the length of jet grouted columns in a soil profile and the effect of soil profiles of varying thickness on the settlements of building structure when the soil is liquefied during an earthquake. The results show that liquefaction-induced large settlements of shallow foundation of building decrease to tolerable limits with the increase in the length of columns. For soil profiles, with a relatively thinner liquefiable layer, a certain minimum length of columns (extended in base non liquefiable layer is required to meet the settlement tolerable limits. For soil profiles, with a relatively thicker liquefiable layer, this length should be equal to the thickness of the liquefiable layer from the footing base plus some extension in the base non liquefiable dense layer. In the soil profile with the base liquefiable layer underlying the non liquefiable layer, settlements could not be reduced to the tolerable limits even with columns of relatively larger length which may be critical.

  9. Compartmental modeling of PAH transport in soil column experiments under variably-saturated flow conditions

    Science.gov (United States)

    Sartori, F.; Sericano, J. L.; Wade, T. L.; Mohanty, B. P.

    2012-12-01

    Knowledge about the mobilization of polycyclic aromatic hydrocarbons (PAH) from PAH-laden soils or sediments is important to understand their bioavailability, and ultimately assess the environmental risk of PAH transport from surface soils into the groundwater. The transport and kinetics of three PAH from a spiked soil layer (2-3 cm soil depth), Phenanthrene-d10 (1900 ng/g), Naphthalene-d8 (1500 ng/g), and Pyrene-d10 (1800 ng/g), were investigated by performing a series of 8 rainfall events during 25 days in two large, replicate soil columns (length: 35 cm; diameter: 14.5 cm; 1 Pore Volume [PV]=2.29 L) under variably-saturated flow conditions. The water-methanol displacing solutions were at volumetric fractions of 0.3 and 0.6 during day 1 (E1) through E8 and E12-E22, respectively. Soil matric potential (h) was monitored at 5-cm and 20-cm depth and volumetric water content (θ) at 12.5-cm and 27.5-cm depth. Soil solution was sampled at 5 cm- (n=46) and 27.5-cm depth (n=46), and the effluent at the bottom of the column (n=163). HYDRUS-1D was used for inverse modeling of h and θ data and to predict θ at specific times and soil depth increments. First-order kinetics, compartmental models describing the transfer of PAH from the soil compartment to the soil solution compartment (desorption) and vice versa (sorption), were used to estimate mass transfer rates (φs, sorption; φd, desorption; φe, elimination), PAH mass in each compartment, and partition coefficients (Kd). Phenanthrene breakthrough curve could be interpreted through a two-parameter, two-compartment model corresponding to the common two-site sorption model, whose parameter estimates (and 95% confidence intervals) were φd=2.72 (2.31, 3.19) PV-1 and φe=4.67 (3.82, 5.7 ) PV-1. Naphthalene breakthrough curve followed a simple one-compartment elimination model, φe=2.0 (1.9, 2.1) PV-1, and that of Pyrene a three-parameter, two-compartment model, φs=0.0454 (0.00853, 0.0603) PV-1, φd=0.165 (0.0319, 0.855) PV

  10. Strength change of clay in the vicinity of soil-cement column; Soil cement kairyotai dasetsu ni tomonau shuhen nendo no sendan kyodo henka

    Energy Technology Data Exchange (ETDEWEB)

    Miura, N.; Koga, K. [Saga University, Saga (Japan). Faculty of Science and Engineering; Shen, S. [Saga University, Saga (Japan); Nakamura, R.

    1998-06-21

    In relation to the installation of the improved soil cement column for improving soft ground, a laboratory experiment and on-site experimental installation are carried out for the study of the surrounding area supporting mechanism of the improved column. In the laboratory experiment, a column is installed using cement slurry into a model ground prepared by placing Ariake clay in a concrete tank, and a load test is conducted after a 28-day curing. In the on-site installation experiment, a column is installed near the mouth of a river flowing into the Ariake Sea, where changes in pore water pressure and soil strength, the latter by use of a double tube cone, are measured before and after the installation, and specimens are collected. Studies are conducted and findings are obtained as outlined below. The effects on the surrounding clay of the improved soil cement column installation consist of a decrease in soil strength during the installation, its recovery to the normal level, and an increase in soil strength due to recompaction and cementation to follow. Surrounding the installed column, there is formed a solidified region as wide as several percent of the column radius and, further surrounding the solidified region, there is formed a region with its strength enhanced, which is as wide by 1.5-20 times as the column radius. 26 refs., 19 figs., 2 tabs.

  11. Response of Atmospheric-Methane Oxidation to Methane-Flux Manipulation in a Laboratory Soil-Column Experiment

    Science.gov (United States)

    Schroth, M. H.; Mignola, I.; Henneberger, R.

    2015-12-01

    Upland soils are an important sink for atmospheric methane (CH4). Uptake of atmospheric CH4 in soils is generally diffusion limited, and is mediated by aerobic CH4 oxidizing bacteria (MOB) that possess a high-affinity form of a key enzyme, allowing CH4 consumption at near-atmospheric concentrations (≤ 1.9 µL/L). As cultivation attempts for these high-affinity MOB have shown little success, there remains much speculation regarding their functioning in different environments. For example, it is frequently assumed that they are highly sensitive to physical disturbance, but their response in activity and abundance to changes in substrate availability remains largely unknown. We present results of a laboratory column experiment conducted to investigate the response in activity and abundance of high-affinity MOB to an increase in CH4 flux. Intact soil cores, collected at a field site where atmospheric CH4 oxidation activity is frequently quantified, were transferred into two 1-m-long, 12-cm-dia. columns. The columns were operated at constant temperature in the dark, their headspace being continuously flushed with air. Diffusive gas-transport conditions were maintained in the reference column, whereas CH4 flux was increased in several steps in the treatment column by inducing advective gas flow using a diaphragm pump. Soil-gas samples periodically collected from ports installed along the length of the columns were analyzed for CH4 content. Together with measurements of soil-water content, atmospheric CH4 oxidation was quantified using the soil-profile method. First results indicate that atmospheric CH4 oxidation activity comparable with the field was maintained in the reference column throughout the experiment. Moreover, high-affinity MOB quickly adjusted to an increase in CH4 flux in the treatment column, efficiently consuming CH4. Quantification of MOB abundance is currently ongoing. Our data provide new insights into controls on atmospheric CH4 oxidation in soils.

  12. Investigating an Inverted Soil Column in Northern Tanzania: Could Intense Groundwater Weathering be the Culprit?

    Science.gov (United States)

    Little, M. G.; Lee, C. A.

    2004-12-01

    Weathering of silicate rocks permanently sequesters a significant amount CO2 on our planet (Berner et al., 1983; Dessert et al., 2003; Gaillardet et al., 1999). Therefore, the investigation of soils and their conjugate protoliths have implications for a wide range of disciplines from soil to atmospheric sciences. This study investigates soil formed in Northern Tanzania on the southern slope of the dormant volcano Mt. Kilimanjaro. Our sample site is in the Machame region at an elevation of ~1640 m where the phonotephrite to basaltic bedrock has been dated at 0.4 to 0.5 million years (Evernden and Curtis, 1965). We determined bulk elemental concentrations of soil and bedrock samples from this region using an ICP-MS and XRF. From initial investigations into the bulk soil and bedrock chemistry using a novel mass balance method, we were able to investigate the relative mobility of a suite of elements. Relative abundances of Ta, Nb, Hf, and Zr are constant and therefore these elements are immobile. In contrast, Ti, an element commonly thought to be immobile, is clearly not immobile in our samples. The entire soil column appears to be highly depleted in Si and Ca but enriched in Al. These features indicate extensive weathering and indeed some samples approach bauxite compositions. Surprisingly, however, weathering versus depth is reversed. Si and Ca have been removed by 60 and 70 % respectively from the upper 2 meters, but below 2 m, they have been removed by 95 and 99 %. This means that the soil is more weathered at depth than in the shallowest 2 meters. We believe that ground water weathering is responsible for this inverted soil profile and may increase CO2 consumption estimates by 10-30 % for similarly affected basalts.

  13. Stability of embankments over cement deep soil mixing columns; Estabilidad de terraplenes sobre columnas de suelo-cemento

    Energy Technology Data Exchange (ETDEWEB)

    Morilla Moar, P.; Melentijevic, S.

    2014-07-01

    The deep soil mixing (DSM) is one of the ground improvement methods used for the construction of embankments over soft soils. DSM column-supported embankments are constructed over soft soils to accelerate its construction, improve embankment stability, increase bearing capacity and control of total and differential settlements. There are two traditional design methods, the Japanese (rigid columns) and the scandinavian (soft and semi-rigid columns). Based on Laboratory analysis and numerical analysis these traditional approaches have been questioned by several authors due to its overestimation of the embankment stability considering that the most common failures types are not assumed. This paper presents a brief review of traditional design methods for embankments on DSM columns constructed in soft soils, studies carried out determine the most likely failure types of DSM columns, methods to decrease the overestimation when using limit equilibrium methods and numerical analysis methods that permit detect appropriate failure modes in DSM columns. Finally a case study was assessed using both limited equilibrium and finite element methods which confirmed the overestimation in the factors of safety on embankment stability over DSM columns. (Author)

  14. Chitosan beads as barriers to the transport of azo dye in soil column.

    Science.gov (United States)

    Lazaridis, Nikolaos K; Keenan, Helen

    2010-01-15

    The development of chitosan-based materials as useful adsorbent polymeric matrices is an expanding field in the area of adsorption science. Although chitosan has been successfully used for the removal of dyes from aqueous solutions, no consideration is given to the removal of dyes from contaminated soils. Therefore this study focuses on the potential use of chitosan as an in situ remediation technology. The chitosan beads were used as barriers to the transport of a reactive dye (Reactive Black 5, RB5) in soil column experiments. Batch sorption experiments, kinetic and equilibrium, were performed to estimate the sorption behavior of both chitosan and soil. The chitosan beads were prepared in accordance with published literature and a synthetic soil was prepared by mixing quantities of sand, silt and clay. The synthetic soil was classified according to British Standards. Calcium chloride was used as tracer to define transport rates and other physical experimental parameters. Dye transport reaction parameters were determined by fitting dye breakthrough curves (BTCs) to the HYDRUS-1D version 4.xx software. Fourier Transform-Infra Red (FT-IR) spectroscopy was used to reveal the sorption mechanism. The study showed that chitosan exhibited a high sorption capacity (S(max)=238 mg/g) and pseudo-first sorption rate (k(1)=1.02 h(-1)) coupled with low swelling and increased retardation for the azo dye tested. Thus it has potential as a Permeable Reactive Barrier (PRB) for containment and remediation of contaminated sites.

  15. [Effect of DMPP on inorganic nitrogen transformation and leaching in vertical flow of simulated soil column].

    Science.gov (United States)

    Yu, Qiao-Gang; Chen, Ying-Xu; Zhang, Qiu-Ling; Liang, Xin-Qiang; Li, Hua; Zhang, Zhi-Jian

    2007-04-01

    Using a multi-layer soil column device, the effect of new nitrification inhibitor DMPP (3,4-dimethyl pyrazole phosphate) on nitrogen leaching was studied for understanding the nitrogen vertical transformation and lowering the nitrogen leaching losses. The results indicate that, within 60 days of experiment, the regular urea added with 1% of DMPP can effectively inhibit the ammonium oxidation in the soil, and improve the concentration of NH4(+) -N in soil solution over the 20 cm tilth profile, while decline the concentrations of NO3(-) -N and N2(-) -N. No obvious difference is found on NH4(+) -N concentrations collected from deep layer soil solution under 20 cm between regular urea and the urea added with 1% of DMPP. There is also no significant difference for the NH4(+) -N and NO3(-) -N in the soil solution of deep layer under 40 cm among the treatments of urea by adding with 1% of DMPP within 60 days. So DMPP could be used as an effective nitrification inhibitor to control ammonium oxidation, decline the nitrate leaching losses, minimize the underground water pollution risk and be beneficial for the ecological environment.

  16. A New Method for Determination of Adsorption and Desorption Coefficients of Pesticides with Soil Column Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The adsorption and desorption coefficients of atrazine, methiocarb and simazine on a sandy loam soil were measured in this study with soil column liquid chromatographic (SCLC) technique. The adsorption and desorption data of all the three pesticides followed Freundlich isotherms revealing the existence of hysteresis. In comparing with other methods, SCLC method showed some characteristics such as rapidity, online and accuracy.

  17. Numerical Simulation Of The Treatment Of Soil Swelling Using Grid Geocell Columns

    Directory of Open Access Journals (Sweden)

    Fattah Mohammed Y.

    2015-06-01

    Full Text Available In this paper, a method for the treatment of the swelling of expansive soil is numerically simulated. The method is simply based on the embedment of a geogrid (or a geomesh in the soil. The geogrid is extended continuously inside the volume of the soil where the swell is needed to be controlled and orientated towards the direction of the swell. Soils with different swelling potentials are employed: bentonite base-Na and bentonite base-Ca samples in addition to kaolinite mixed with bentonite. A numerical analysis was carried out by the finite element method to study the swelling soil's behavior and investigate the distribution of the stresses and pore water pressures around the geocells beneath the shallow footings. The ABAQUS computer program was used as a finite element tool, and the soil is represented by the modified Drucker-Prager/cap model. The geogrid surrounding the geocell is assumed to be a linear elastic material throughout the analysis. The soil properties used in the modeling were experimentally obtained. It is concluded that the degree of saturation and the matric suction (the negative pore water pressure decrease as the angle of friction of the geocell column material increases due to the activity of the sand fill in the dissipation of the pore water pressure and the acceleration of the drainage through its function as a drain. When the plasticity index and the active depth (the active zone is considered to be equal to the overall depth of the clay model increase, the axial movement (swelling movement and matric suction, as a result of the increase in the axial forces, vary between this maximum value at the top of the layer and the minimum value in the last third of the active depth and then return to a consolidation at the end of the depth layer.

  18. Laboratory evaporation experiments in undisturbed peat columns for determining peat soil hydraulic properties

    Science.gov (United States)

    Dettmann, U.; Frahm, E.; Bechtold, M.

    2013-12-01

    Knowledge about hydraulic properties of organic soils is crucial for the interpretation of the hydrological situation in peatlands. This in turn is the basis for designing optimal rewetting strategies, for assessing the current and future climatic water balance and for quantifying greenhouse gas emissions of CO2, CH4 and N2O, which are strongly controlled by the depth of the peat water table. In contrast to mineral soils, the hydraulic properties of organic soils differ in several aspects. Due to the high amount of organic components, strong heterogeneity, and shrinkage and swelling of peat, accompanied by changing soil volume and bulk density, the applicability of standard hydraulic functions developed for mineral soils for describing peat soil moisture dynamics is often questioned. Hence, the objective of this study was to investigate the applicability of the commonly applied van Genuchten-Mualem (VGM) parameterization and to evaluate model errors for various peat types. Laboratory column experiments with undisturbed peat soils (diameter: 30 cm, height: 20 cm) from 5 different peatlands in Germany were conducted. In numerical simulations using HYDRUS-1D the experimental data were used for an inverse estimation of the soil hydraulic parameters. Using the VGM parameterization, the model errors between observed and measured pressure heads were quantified with a root mean square error (RMSE) of 20 - 65 cm. The RMSE increased for soils with higher organic carbon content and higher porosity. Optimizing the VGM 'tortuosity' parameter (τ) instead of fixing it to its default of 0.5 strongly reduced the RMSE, especially for the soils that showed high pressure head gradients during the experiment. Due to the fact, that very negative pressure heads in peatlands occur rarely, we reduced the range of pressured heads in the inversion to a 'field-relevant' range from 0 to -200 cm which strongly reduced the RMSE to 6 - 12 cm and makes the VGM parameterization applicable for all

  19. Endosulfan sulfate mobility in soil columns and pesticide pollution of groundwater in Northwest Morocco.

    Science.gov (United States)

    El Bakouri, Hicham; Ouassini, Abdelhamid; Morillo Aguado, José; Usero García, José

    2007-12-01

    Groundwater pollution from agricultural practices is a serious environmental and health problem. In this work, stir bar sorptive extraction (SBSE) and gas chromatography (GC) with mass spectrometry (MS) detection were used to determine phytosanitary products in groundwater samples from the Loukkos perimeter in Northwest Morocco. Some pesticides--in particular, endosulfan and its metabolites--were found in water destined for human consumption. Analyses of soil samples were also carried out, and the results showed endosulfan sulfate and endosulfan ether in abundance. Endosulfan sulfate leaching was also performed in undisturbed soil columns to obtain more information on the vertical migration of pesticides used in the perimeter. The kinetic study showed a high recovery rate (73%) after 10 days of experimental work.

  20. Monitoring Anaerobic TCE Degradation by Evanite Cultre in Column Packed with TCE-Contaminated Soil

    Science.gov (United States)

    Ko, J.; Han, K.; Ahn, G.; Park, S.; Kim, N.; Ahn, H.; Kim, Y.

    2011-12-01

    Trichloroethylene (TCE) is a long-term common groundwater pollutant because the compound with high density is slowly released into groundwater. Physical and chemical remediation processes have been used to clean-up the contaminant, but novel remediation technology is required to overcome a low efficiency of the traditional treatment process. Many researchers focused on biological process using an anaerobic TCE degrading culture, dehalococcoides spp., but it still needs to evaluate whether the process can be applied into field scale under aerobic condition. Therefore, in this work we examined two different types (i.e., Natural attenuation and bioaugmentation) of biological remediation process in anaerobic column packed with TCE-contaminated soil. A TCE degradation by indigenous microorganisms was confirmed by monitoring TCE and the metabolites (c-DCE, VC, ETH). However, TCE was transformed and stoichiometry amount of c-DCE was produced, and VC and ETH was not detected. To test bioaugmentation of Evanite culture containing dehalococcoides spp., Evanite culture was injected into the column and TCE degradation to c-DCE, VC, ETH was monitored. We are evaluating the transport of the Evanite culture in the column by measuring TCE and VC reductases. In the result, the TCE was completely degraded to ETH using hydrogen as electron donor generate by hydrogen-production fermentation from formate.

  1. The response of soil biota to phosphate fertilization in grassland columns

    Science.gov (United States)

    Ikoyi, Israel; Winstanley, Henry; Fowler, Andrew; Schmalenberger, Achim

    2017-04-01

    The United Nations has predicted that food production is expected to rise by 50% in the year 2020 to feed the increasing world population. Grasslands play significant roles in food production and occupy about 70% of the world's agricultural land. However, intensive use of inorganic fertilizers often associated with increased food production can lead to poor soil quality and environmental pollution. For instance, excessive phosphorus (P) application can lead to eutrophication in surface waters. Although P plays vital roles in many metabolic processes in plants, its primary source rock phosphate is finite. Consequently, the development of more P efficient agricultural systems is paramount. P cycling within the microbial biomass is essential to the P cycle within the soil with its key pathways for P mobilization and mineralization from various soil pools into plant available forms. In this study, soil columns were setup in a greenhouse using a P deficient Irish soil (P index 1). The columns were planted with Lolium perenne and fertilized with 0, 5, 10 and 20 kg/ha inorganic P representing control, low, medium and high rates respectively alongside a full complement of other nutrients. Each treatment was replicated six times and managed for 14 weeks. Results after 14 weeks showed that the weekly measurements of phosphate at different soil depths identified only traces of P in soil solution for the duration of 14 weeks, even after P application. There was a significant increase in alkaline and acid phosphatase activities with the high P compared to the control but no significant effect on plant shoot and root biomass, abundances of cultivable calcium phosphate-, phytate- and phosphonate-utilizing bacteria upon P fertilization. L. perenne rhizosphere of the highest P treatment had significantly lower abundance of bacterial phoD genes, mycorrhizal hyphal and arbuscular colonization rates compared to the control. Likewise, the abundance of bacterial- and fungal

  2. Hoop column soil moisture spacecraft in low Earth orbit for global change monitoring

    Science.gov (United States)

    Ferebee, Melvin J., Jr.

    1991-01-01

    A subset of the total Global Change Technology Initiative instruments are required to be in low Earth, sunsynchronous orbits. There is one instrument, however, that requires its own specialized spacecraft; the Soil Moisture Microwave Radiometer (SMMR). The characteristic structure of the instrument is the 118 m hoop column support structure. The hoop is supported by an axially placed column. Tension cables support and shape an electromagnetically reflective mesh surface. The instrument is capable of detecting frequencies in the 1.4 GHz range (Soil Moisture and Sea Salinity). Three apertures are used to reduce the degree of paraboloid offset and improve the beam quality. The spacecraft configuration is determined by the instrument support requirements and the requirement that it can fit into the Titan IV cargo bay. The configuration is derived by cross referencing the instrument performance requirements with the performance of the spacecraft. The spacecraft design is similar with the Multi-mission Modular Spacecraft in terms of size and packaging. A description of the spacecraft's features will yield a summary of the technologies needed for the SMMR spacecraft.

  3. Gamma ray transmission for hydraulic conductivity measurement of undisturbed soil columns

    Directory of Open Access Journals (Sweden)

    Anderson Camargo Moreira

    2007-03-01

    Full Text Available This work had the objective to determine the Hydraulic Conductivity K(theta function for different depth levels z, of columns of undisturbed soil, using the gamma ray transmission technique applied to the Sisson method. The results indicated a growing behavior for K(theta and a homogeneous soil density, both in relation to the increase of the depth. The methodology of gamma ray transmission showed satisfactory results on the determination of the hydraulic conductivity in columns of undisturbed soil, besides being very reliable and a nondestructive method.O estudo da condutividade hidráulica para solos não saturados é essencial quando aplicado às situações relacionadas à irrigação, drenagem e transporte de nutrientes no solo, é uma importante propriedade para desenvolvimentos de culturas agrícolas. Este trabalho tem o objetivo de determinar a função Condutividade Hidráulica K(teta, em diferentes níveis z de profundidade, em colunas de solo indeformado, utilizando a transmissão de raios gama aplicada ao método de Sisson. Os resultados indicam um comportamento crescente para K(teta e uma densidade de solo homogênea, ambos em relação ao aumento da profundidade. A metodologia de transmissão de raios gama mostrou resultados bastante satisfatórios na determinação da condutividade hidráulica em colunas de solo indeformado, além de ser muito confiável e não destrutivo.

  4. P losses in soil columns amended with compost and digestate from municipal solid wastes

    Science.gov (United States)

    García-Albacete, Marta; Cartagena, M. Carmen

    2013-04-01

    Sludge's, manures and compost applied to agricultural soils in high quantities and long-term application to increase crop productivity, result in accumulation of soil phosphorous (P). Soluble P is directly available to algae (Sonzogni et al., 1982) and thus particularly relevant to water quality degradation. Transport of P from agricultural soils to surface waters has been linked to eutrophication in fresh water and estuaries (Sharpley and Lemunyon, 1998). Almost 50% of stored water in Spain is degraded by eutrophication processes that cause the proliferation of algae and other organisms and a decrease in oxygen content (Environmental Profile of Spain 2005). Fertilizers and biodegradable wastes application rates in agriculture are based on nitrogen requirements. This results in a P supply that is in excess of crops needs since the ratio of P to N in waste use to be greater than required by plants (Smith, 1995). While surface runoff is an important pathway of phosphorus losses from agricultural lands, significant losses can also occur via leaching thought soils. Leaching tests are important for assessing the risk of release of potential pollutants from biodegradable wastes into groundwater or surface water. Percolation tests also get information about the interaction of organic waste with soils. The study was conducted according to the percolation leaching test CEN/TS 14405 "Characterization of waste-Leaching behavior test- Up-flow percolation test" with three different soils mixed with organic wastes from msw (compost and digestato) and an inorganic fertilizer (NaH2PO4). Each soil was amended with the P sources at rates of 100 kg P ha-1. Leachates were collected and analyzed for each column for dissolved reactive P by inductively coupled plasma atomic emission spectroscopy (ICP) following USEPA Method 3050A digestion (USEPA, 1995). The fact that P sorption capacity (Xmax, PSI) of the soils was determined using Langmuiŕs isotherms and the P forms from organic

  5. Sulfadimethoxine transport in soil columns in relation to sorbable and non-sorbable tracers.

    Science.gov (United States)

    Park, Jong Yol; Huwe, Bernd

    2016-06-01

    In this study, miscible displacement experiment and batch sorption experiments were performed with sulfadimethoxine, dye tracer, Brilliant Blue FCF (BB) and a conservative tracer (bromide) to depict, analyse and interpret transport paths of sulfadimethoxine in undisturbed and disturbed soil columns. Batch sorption experiment revealed that sorption potential increased in the order: Brilliant Blue FCF > sulfadimethoxine > bromide. The horizontal spatial patterns of sulfadimethoxine and the tracers were analysed in each depth, and selective samples were taken in horizontal cross-section. Non-adsorbable and conservative tracer, bromide spread more widely into longitudinal and horizontal direction than sulfadimethoxine and Brilliant Blue FCF, since adsorption reduced transversal dispersion of the sulfadimethoxine and dye. In non-stained area, residual concentrations of sulfadimethoxine were relatively lower than in stained areas. Therefore, Brilliant Blue FCF distribution can be used to approximate sulfadimethoxine movement in soil. However, presence of preferential flow networks found in undisturbed soil cores can enhance mobility of sulfadimethoxine and the tracers, due to faster flow velocities and non-equilibrium adsorption. Our findings showed that other dye tracers may also be applicable to identify transport pathways of various organic contaminants, of which physico-chemical properties are similar to those of the dye tracers. Preferential flow should be considered for drinking water managements and transport modelling, since this allows faster pollutants transport from their sources, and create critical consequences for groundwater quality and solute transport modelling.

  6. Modelling Pesticide Leaching At Column, Field and Catchment Scales Ii. Influence of Soil Variability On Small Scale Transfer Properties

    Science.gov (United States)

    Roulier, S.; Jarvis, N.

    The aim of this study was to investigate the differences in small scale transfer prop- erties in relation to variability of soil characteristics in a small undulating agricultural catchment (Vemmenhög, 9 km2), where texture and organic C content are strongly related to landscape position (see Gärdenäs et al., this session). Undisturbed soil col- umn samples (20 cm diameter, 20 cm height) were taken at two locations (4 columns at each location): on a hilltop (high clay content), and in a hollow (high C content). Transient leaching experiments for a tracer and a herbicide (MCPA) were carried out in two steps. After a first application of solute and pesticide the columns were ex- posed to natural rainfall. After one pore volume of drainage had flowed through the columns, they were transferred indoors. A second dose of tracer and pesticide was applied, and the columns were irrigated with half a pore volume of natural rainwa- ter. The breakthrough curves obtained for the hilltop columns showed strong evidence of macroporous flow. The flux concentrations and the resident concentration at the end of the experiment measured for the hollow columns suggested that the loss of pesticide from those columns is little. The MACRO model and the inverse modelling package SUFI were used to estimate the small scale parameters for water transfer, so- lute transport, and pesticide. Good agreement was obtained between model and data. Macroporous flow and diffusive transport through hilltop columns was highlighted by the high calibrated values of the effective diffusion pathlength and the dispersivity. As a consequence of the significant organic C content in the hollows, the value of the degradation rate coefficient for hollow columns was important. In both hilltop and hollow columns, the variation of the degradation rate coefficient between the first and the second application of MCPA showed the ability of the micro-organisms to adapt to the pesticide.

  7. An in situ inventory of fungi and their associated migrating bacteria in forest soils using fungal highway columns.

    Science.gov (United States)

    Simon, Anaele; Hervé, Vincent; Al-Dourobi, Andrej; Verrecchia, Eric; Junier, Pilar

    2017-01-01

    Soils are complex ecosystems in which fungi and bacteria co-exist and interact. Fungal highways are a kind of interaction by which bacteria use fungal hyphae to disperse in soils. Despite the fact that fungal highways have been studied in laboratory models, the diversity of fungi and bacteria interacting in this way in soils is still unknown. Fungal highway columns containing two different culture media were used as a selective method to study the identity of fungi and bacteria able to migrate along the hyphae in three forest soils. Regardless of the soil type, fungi of the genus Mortierella (phylum Zygomycota) were selected inside the columns. In contrast, a diverse community of bacteria dominated by Firmicutes and Proteobacteria was observed. The results confirm the importance of bacteria affiliated to Burkholderia as potentially associated migrating bacteria in soils and indicate that other groups such as Bacillus and Clostridium are also highly enriched in the co-colonization of a new habitat (columns) associated to Mortierella. The diversity of potentially associated migrating bacteria brings a novel perspective on the indirect metabolic capabilities that could be favored by r-strategist fungi and supports the fact that these fungi should be considered as crucial actors in soil functioning. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. [Aliphatic characteristics of the fractions isolated from the soil fulvic acid using XAD-8 column].

    Science.gov (United States)

    Liu, Ben-ding; Li, Xia; Dai, Jing-yu

    2007-10-01

    In order to truly understand the character and structure of fulvic acid, which contains many substances, the authors isolated fulvic acid detailedly according to its definite character and its characteristic of similar structure. Fulvic acid with H+ can be adsorbed by the XAD-8 column balanced by the usual buffer(pH 2). The hydrophilic fraction in fulvic acid can be divided into three groups using the buffer with various pH (4.8, 7.0 and 11.0), while the hydrophobic fraction can be classified into two groups by the distilled water and alcohol separately. For FTIR (Fourier transform infrared) and NMR (nuclear magnetic resonance) spectroscopy analysis, three paddy soils were used. It may be concluded that the content of oxygen and carboxyl group dissolved at low pH is more than that dissolved in the water and alcohol, but the content of aliphatic fraction is less and has short side chain.

  9. Simulation of estrogen transport and behavior in laboratory soil columns using a cellular automata model

    Science.gov (United States)

    Chen, Qingcai; Shi, Jianghong; Liu, Xiaowei; Wu, Wei; Liu, Bo; Zhang, Hui

    2013-03-01

    A cellular automata model (CA model) was used to simulate the soil column leaching process of estrogens during the processes of migration and transformation. The results of the simulated leaching experiment showed that the first-order degradation rates of 17α-ethynylestradiol (EE2), 17β-estradiol (E2) and estrone (E1) were 0.131 h- 1 for E2, 0.099 h- 1 for E1 and 0.064 h- 1 for EE2 in the EE2 and E2 leaching process, and the first-order sorption rates were 5.94 h- 1 for E2, 5.63 h- 1 for EE2, 3.125 h- 1 for E1. Their sorption rates were positively correlated with the n-octanol/water partition coefficients. When the diffusion rate was low, its impact on the simulation results was insignificant. The increase in sorption and degradation rates caused the decrease in the total estrogens that leached. In addition, increasing the sorption rate could delay the emerging time of the maximum concentration of estrogen that leached, whereas increasing the degradation rate could shorten the emerging time of the maximum concentration of estrogen that leached. The comparison made between the experimental data and the simulation results of the CA model and the HYDRUS-1D software showed that the establishment of one-component and multi-component CA models could simulate EE2 and E2 soil column leaching processes, and the CA models achieve an intuitive, dynamic, and visual simulation.

  10. 19 CFR 19.8 - Examination of goods by importer; sampling; repacking; examination of merchandise by prospective...

    Science.gov (United States)

    2010-04-01

    ... conduct of Customs business and no danger to the revenue prospective purchaser may be permitted to examine...; repacking; examination of merchandise by prospective purchasers. 19.8 Section 19.8 Customs Duties U.S... goods by importer; sampling; repacking; examination of merchandise by prospective purchasers. Importers...

  11. SoilJ - An ImageJ plugin for semi-automatized image-processing of 3-D X-ray images of soil columns

    Science.gov (United States)

    Koestel, John

    2016-04-01

    3-D X-ray imaging is a formidable tool for quantifying soil structural properties which are known to be extremely diverse. This diversity necessitates the collection of large sample sizes for adequately representing the spatial variability of soil structure at a specific sampling site. One important bottleneck of using X-ray imaging is however the large amount of time required by a trained specialist to process the image data which makes it difficult to process larger amounts of samples. The software SoilJ aims at removing this bottleneck by automatizing most of the required image processing steps needed to analyze image data of cylindrical soil columns. SoilJ is a plugin of the free Java-based image-processing software ImageJ. The plugin is designed to automatically process all images located with a designated folder. In a first step, SoilJ recognizes the outlines of the soil column upon which the column is rotated to an upright position and placed in the center of the canvas. Excess canvas is removed from the images. Then, SoilJ samples the grey values of the column material as well as the surrounding air in Z-direction. Assuming that the column material (mostly PVC of aluminium) exhibits a spatially constant density, these grey values serve as a proxy for the image illumination at a specific Z-coordinate. Together with the grey values of the air they are used to correct image illumination fluctuations which often occur along the axis of rotation during image acquisition. SoilJ includes also an algorithm for beam-hardening artefact removal and extended image segmentation options. Finally, SoilJ integrates the morphology analyses plugins of BoneJ (Doube et al., 2006, BoneJ Free and extensible bone image analysis in ImageJ. Bone 47: 1076-1079) and provides an ASCII file summarizing these measures for each investigated soil column, respectively. In the future it is planned to integrate SoilJ into FIJI, the maintained and updated edition of ImageJ with selected

  12. Evaluation of nitrification inhibitor 3,4-dimethyl pyrazole phosphate on nitrogen leaching in undisturbed soil columns.

    Science.gov (United States)

    Yu, Qiaogang; Chen, Yingxu; Ye, Xuezhu; Zhang, Qiuling; Zhang, Zhijian; Tian, Ping

    2007-03-01

    The application of nitrogen fertilizers leads to various ecological problems such as nitrate leaching. The use of nitrification inhibitors (NI) as nitrate leaching retardants is a proposal that has been suggested for inclusion in regulations in many countries. In this study, the efficacy of the new NI, 3,4-dimethyl pyrazole phosphate (DMPP), was tested under simulated high-risk leaching situations in two types of undisturbed soil columns. The results showed that the accumulative leaching losses of soil nitrate under treatment of urea with 1.0% DMPP, from columns of silt loam soil and heavy clay soil, were 66.8% and 69.5% lower than those soil columns tested with regular urea application within the 60 days observation, respectively. However, the losses of ammonium leaching were reversely increased 9.7% and 6.7% under the former treatment than the latter one. Application of regular urea with 1.0% DMPP addition can reduce about 59.3%-63.1% of total losses of inorganic nitrogen via leaching. The application of DMPP to urea had stimulated the inhibition effects of DMPP on the ammonium nitrification process in the soil up to 60 days. It is proposed that the DMPP could be used as an effective NI to control inorganic N leaching losses, minimizing the risk of nitrate pollution in shallow groundwater.

  13. Flow injection with in-line reduction column and conductometric detection for determination of total inorganic nitrogen in soil.

    Science.gov (United States)

    Yanu, Pattama; Jakmunee, Jaroon

    2015-11-01

    A cost effective flow injection (FI) conductometric system has been developed for determination of total inorganic nitrogen (TIN). The system is aimed for evaluation of nitrogen nutrient in soil for agricultural application. Inorganic nitrogen compounds were extracted from soil according to the standard method by using potassium chloride solution as an extractant, and the extracted solution was then injected into the FI system. Nitrate and nitrite are converted to ammonium ion by an in-line reduction column packed with a Devarda's alloy. A gas diffusion unit was incorporated into the FI system to separate ammonium ion from other ions in a donor stream by forming ammonia gas that can diffuse through a PTFE membrane to re-dissolve in an acceptor stream. Conductance of the acceptor stream was directly proportional to ammonium ion concentration. Various parameters affecting reduction efficiency of the column, e.g., column diameter, column packing procedure, and column length was investigated and optimized. A linear calibration graph in the range of 2.00-60.00 mg L(-1) N-NH4(+) (y=0.123x+0.039, R(2) =0.997) was obtained with a limit of detection of 0.47 mg L(-1). Sample throughput of 20 samples h(-1) was achieved. The result of developed method was correlated with total Kjeldahl nitrogen (TKN) obtained from the Kjeldahl digestion method. The proposed method could be used as an alternative method to the Kjeldahl method for determination of TIN in soil.

  14. Enhanced retention of linuron, alachlor and metalaxyl in sandy soil columns intercalated with wood barriers.

    Science.gov (United States)

    Rodríguez-Cruz, M S; Ordax, J M; Arienzo, M; Sánchez-Martín, M J

    2011-03-01

    A study has been made of the effect a reactive barrier made of pine (softwood) or oak (hardwood) wood intercalated in a sandy soil column has on the retention of linuron, alachlor and metalaxyl (pesticides with contrasting physicochemical characteristics). The leaching of pesticides has been carried out under a saturated flow regime and breakthrough curves (BTCs) have been obtained at flow rates of 1 m Lmin(-1) (all pesticides) and 3 m Lmin(-1) (linuron). The cumulative curves in the unmodified soil indicate a leaching of pesticides >80% of the total amount of compound added. After barrier intercalation, linuron leaching decreases significantly and a modification of the leaching kinetics of alachlor and metalaxyl has been observed. The theoretical R factors increased ∼2.6-3.3, 1.2-1.6-fold, and 1.4-1.7-fold and the concentration of the maximum peak decreased ∼6-12-fold, 2-4-fold and 1.2-2-fold for linuron, alachlor and metalaxyl, respectively. When considering the three pesticides, significant correlations have been found between the theoretical retardation factor (R) and the pore volume corresponding to the maximum peaks of the BTCs (r=0.77; pmetalaxyl. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Experimental studies on the physico-mechanical properties of jet-grout columns in sandy and silty soils

    Science.gov (United States)

    Akin, Muge K.

    2016-04-01

    The term of ground improvement states to the modification of the engineering properties of soils. Jet-grouting is one of the grouting methods among various ground improvement techniques. During jet-grouting, different textures of columns can be obtained depending on the characteristics of surrounding subsoil as well as the adopted jet-grouting system for each site is variable. In addition to textural properties, strength and index parameters of jet-grout columns are highly affected by the adjacent soil. In this study, the physical and mechanical properties of jet-grout columns constructed at two different sites in silty and sandy soil conditions were determined by laboratory tests. A number of statistical relationships between physical and mechanical properties of soilcrete were established in this study in order to investigate the dependency of numerous variables. The relationship between qu and γd is more reliable for sandy soilcrete than that of silty columns considering the determination coefficients. Positive linear relationships between Vp and γd with significantly high determination coefficients were obtained for the jet-grout columns in silt and sand. The regression analyses indicate that the P-wave velocity is a very dominant parameter for the estimation of physical and mechanical properties of jet-grout columns and should be involved during the quality control of soilcrete material despite the intensive use of uniaxial compressive strength test. Besides, it is concluded that the dry unit weight of jet-grout column is a good indicator of the efficiency of employed operational parameters during jet-grouting.

  16. Effect of grass cover on water and pesticide transport through undisturbed soil columns, comparison with field study (Morcille watershed, Beaujolais)

    Energy Technology Data Exchange (ETDEWEB)

    Dousset, S., E-mail: sylvie.dousset@limos.uhp-nancy.f [Nancy-Universite, CNRS, LIMOS, BP 70239, 54506 Vandoeuvre-les-Nancy (France); Thevenot, M. [Universite de Lille 1, CNRS, Geosystemes, 59655 Villeneuve d' Ascq (France); Schrack, D. [INRA-SAD ASTER, 88500 Mirecourt (France); AFSSA, Laboratoire d' Etudes et de Recherches en Hydrologie, 54000 Nancy (France); Gouy, V.; Carluer, N. [UR Milieux Aquatiques, Ecologie et Pollution, Cemagref, 69336 Lyon Cedex (France)

    2010-07-15

    The purpose of this work is to assess the effectiveness of two grass covers (buffer zone and grass-covered inter-row), to reduce pesticide leaching, and subsequently to preserve groundwater quality. Lower amounts of pesticides leached through grass-cover soil columns (2.7-24.3% of the initial amount) than the bare soil columns (8.0-55.1%), in correspondence with their sorption coefficients. Diuron was recovered in higher amounts in leachates (8.9-32.2%) than tebuconazole (2.7-12.9%), in agreement with their sorption coefficients. However, despite having a sorption coefficient similar to that of diuron, more procymidone was recovered in the leachates (10.2-55.1%), probably due to its facilitated transport by dissolved organic matter. Thus even in this very permeable soil, higher organic matter contents associated with grass-cover reduce the amount of pesticide leaching and limit the risk of groundwater contamination by the pesticides. The results of diuron and tebuconazole transfer through undisturbed buffer zone soil columns are in agreement with field observations on the buffer zone. - Grass-covered soils reduce the amount of pesticide leaching, due mainly to their higher organic matter contents, thereby reducing the risk of groundwater contamination.

  17. Persistence and Leaching Potential of Microorganisms and Mineral N in Animal Manure Applied to Intact Soil Columns

    DEFF Research Database (Denmark)

    Mostofa Amin, M. G.; Forslund, Anita; Bui, Thanh Xuan

    2013-01-01

    Pathogens may reach agricultural soils through application of animal manure and thereby pose a risk of contaminating crops as well as surface and groundwater. Treatment and handling of manure for improved nutrient and odor management may also influence the amount and fate of manure-borne pathogens...... in the soil. A study was conducted to investigate the leaching potentials of a phage (Salmonella enterica serovar Typhimurium bacteriophage 28B) and two bacteria, Escherichia coli and Enterococcus species, in a liquid fraction of raw pig slurry obtained by solid-liquid separation of this slurry...... and in this liquid fraction after ozonation, when applied to intact soil columns by subsurface injection. We also compared leaching potentials of surface-applied and subsurface-injected raw slurry. The columns were exposed to irrigation events (3.5-h period at 10 mm h−1) after 1, 2, 3, and 4 weeks of incubation...

  18. Examination of Technetium Transport Through Soils Under Contrasting Redox Conditions: Batch and Column Work

    Science.gov (United States)

    Dozier, R.; Montgomery, D.; Wylie, E. M.; Dogan, M.; Moysey, S. M.; Powell, B. A.; Martinez, N. E.

    2015-12-01

    Experiments were performed under various reducing conditions to evaluate the transport behavior of technetium-99 (99Tc) in the presence of sandy clay loam soil from the Savannah River Site (SRS) and goethite, magnetite, and iron sulfide, which were selected for their increasing reducing potential. The experiments were conducted to investigate how redox reaction equilibria and rates affect the overall mobility of 99Tc as it transitions between the mobile Tc(VII) and immobile Tc(IV). Under oxygen-rich conditions, batch sorption isotherms measured for TcO4- across the concentration range 0.5 to 50 μg/L were linear with distribution coefficients (Kd) of 0.78 mL/g or lower, with decreasing sorption for goethite, magnetite, and iron sulfide, respectively. Addition of Na2S resulted in a marked increase in apparent 99Tc sorption to the solid phase, with Kd of 43 mL/g, 35 mL/g, and 29 mL/g, following the same mineral trend as previously. The increased Kd values are possibly due to reduction of Tc(VII) to Tc(IV), resulting in the formation of TcO2(s). SRS soil batch sorption isotherms measured for TcO4- across the same concentration range were also linear, with Kd of 0.7 mL/g for unadjusted pH, 5.1 mL/g for pH of around 6, and 6.7 mL/g for pH of around 4. Kinetic batch sorption tests showed less than 10% 99Tc sorption in an oxidizing environment and greater than 95% sorption in a reducing environment, with both reactions occurring on the order of minutes. In contrast, desorption experiments initiated by transferring the samples from a reducing environment (0.1% H2(g)/99.9% N2(g)) to atmospheric conditions resulted in a slow desorption step on the order of days. Column experiments conducted with the SRS sands indicate a retardation factor of 1.17 for 99Tc under oxygen rich conditions. Additional column experiments are being conducted to evaluate 99Tc transport dependencies on transitions between oxygen rich and poor conditions.

  19. Estimation of mechanical dispersion and dispersivity in a soil-gas system by column experiments and the dusty gas model.

    Science.gov (United States)

    Hibi, Yoshihiko; Kanou, Yuki; Ohira, Yuki

    2012-04-01

    In a previous study, column experiments were carried out with Toyoura sand (permeability 2.05×10(-11)m(2)) and Toyoura sand mixed with bentonite (permeability 9.96×10(-13)m(2)) to obtain the molecular diffusion coefficient, the Knudsen diffusion coefficient, the tortuosity for the molecular diffusion coefficient, and the mechanical dispersion coefficient of soil-gas systems. In this study, we conducted column experiments with field soil (permeability 2.0×10(-13)m(2)) and showed that the above parameters can be obtained for both less-permeable and more-permeable soils by using the proposed method for obtaining the parameters and performing column experiments. We then estimated dispersivity from the mechanical dispersion coefficients obtained by the column experiments. We found that the dispersivity depended on the mole fraction of the tracer gas and could be represented by a quadratic equation. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Experimental and Particle-Tracking Model Analysis of Anomalous Transport and Sorption of Nickel in Natural Soil Columns

    Science.gov (United States)

    Edery, Y.; Rubin, S.; Dror, I.; Berkowitz, B.

    2012-12-01

    Nickel migration measured in laboratory-scale, natural soil column experiments is shown to display anomalous (non-Fickian) transport and non-equilibrium adsorption and desorption patterns. Similar experiments using a conservative tracer also exhibit anomalous behavior. In parallel batch experiments, adsorption and desorption isotherms demonstrate hysteresis, indicating some permanent adsorption. While adsorption is described by the Langmuir isotherm, equilibrium concentrations are higher than those predicted by the same model for desorption. Furthermore, batch and flow-through column experiments show the occurrence of ion exchange of nickel with magnesium and potassium in the soil; aluminum and other ion concentrations are also affected by the presence of nickel. Strong retention of nickel during transport in soil columns leads to delayed initial breakthrough (~40 pore volumes), slow increase in concentration, and extended concentration tailing at long times. Standard models, including two-site non-equilibrium formulations, fail to capture these features quantitatively. We describe the mechanisms of transport and adsorption/desorption in terms of a continuous time random walk (CTRW) model, and use a particle tracking formulation to simulate the nickel migration in the column. This approach allows us to capture the non-Fickian transport and the subtle local effects of adsorption and desorption. The model uses transport parameters estimated from the conservative tracer and, as a starting point, adsorption/desorption parameters based on the batch experiments to account for the reactions. It is shown that the batch parameters under-estimate the actual adsorption in the column. The CTRW particle tracking model is shown to capture both the full evolution of the measured breakthrough curve and the measured spatial concentration profile. Analysis of these results provides further understanding of the interaction and dynamics between transport and sorption mechanisms in

  1. 21 CFR 801.122 - Medical devices for processing, repacking, or manufacturing.

    Science.gov (United States)

    2010-04-01

    ... manufacturing. 801.122 Section 801.122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND....122 Medical devices for processing, repacking, or manufacturing. A device intended for processing... act if its label bears the statement “Caution: For manufacturing, processing, or repacking”. ...

  2. Transport and survival of Cryptosporidium Parvum Oocysts in Soil Columns Following Applications of Raw and Separated Liquid Slurry

    DEFF Research Database (Denmark)

    Petersen, H.H.; Enemark, Heidi L.; Olsen, A.;

    The widespread waterborne pathogen Cryptosporidium parvum is primarily transmitted to humans via contaminated drinking and recreational water. Nearly all drinking water in Denmark is groundwater, but this can be contaminated with oocysts from application of contaminated manure to the field. Oocysts...... transport to groundwater requires that the oocysts are transported through soil and bedrock to the water table. The purpose of this study was to determine the potential transport of the protozoan pathogen C. parvum through soil to land drains and, subsequently water courses in a laboratory setup using...... simulated rainfall and six 20 cm long replicate intact soil columns. Two types of contaminated slurry, namely raw slurry and the separated liquid fraction of the slurry were applied ten cm into the soil, following irrigation once a week over a four week period. C. parvum oocysts were detected...

  3. Bayesian estimation of the hydraulic and solute transport properties of a small-scale unsaturated soil column

    Directory of Open Access Journals (Sweden)

    Moreira Paulo H. S.

    2016-03-01

    Full Text Available In this study the hydraulic and solute transport properties of an unsaturated soil were estimated simultaneously from a relatively simple small-scale laboratory column infiltration/outflow experiment. As governing equations we used the Richards equation for variably saturated flow and a physical non-equilibrium dual-porosity type formulation for solute transport. A Bayesian parameter estimation approach was used in which the unknown parameters were estimated with the Markov Chain Monte Carlo (MCMC method through implementation of the Metropolis-Hastings algorithm. Sensitivity coefficients were examined in order to determine the most meaningful measurements for identifying the unknown hydraulic and transport parameters. Results obtained using the measured pressure head and solute concentration data collected during the unsaturated soil column experiment revealed the robustness of the proposed approach.

  4. The Response of Nitrifying Bacteria to Treatments of N-Serve and Roundup in Continuous-Flow Soil Columns

    Science.gov (United States)

    1988-07-15

    Mode of Action of Nitrification Inhibitors. In Meisinger, J. J., G. W. Ranfall, M. L. Vitosh, M. Stelly, D. M. Kral, and M. K. Cousin (eds...significantly reduced -i nitrification at 6.8 and 68 mg glyphosate g dry so!l. Continuous-flow columns were examined to determine if microbial...populations were altered by chemical treatment. -I Concentrations of 4.2 mg nitrapyrin and 68 mg glyphosate g dry soil significantly increased heterotrophic

  5. Soil-Column Test on Aniline Degradation in Riverbank Filtration under Denitrification Conditions

    Institute of Scientific and Technical Information of China (English)

    Wu Yaoguo; Wang Hui; Zhang Wencun; Sun Weijian

    2005-01-01

    Drinking water is at risk from aniline pollution and thus aniline degradation and its mechanism have received much attention. In this paper, a soil column, including sediments and aquifer media, was collected from the Weihe riverbed and its bank, and used to research the characteristics of aniline degradation in the riverbank filtration process under denitrification conditions. The results indicate that all aniline could be degraded by the habituated indigenous microbes, and even mostly mineralized under denitrification conditions, but with a long lag phase. Some aniline degradation must involve deamination, while the majority undergoes covalent binding with humic substances to form complexes, and the complexes are easily degraded and even mineralized. During the degradation no intermediates were harmful to denitrifiers. Therefore, under denitrifaction conditions, aniline is degraded in RBF, and up to now aniline has not been monitored in the groundwater along the polluted river. During the 153 d testing process, the nitrate-nitrogen concentration was about 23.0 mg/L, and aniline concentrations were 40, 80 or 400 mg/L at 0-74 d, 75-105 d and 106-153 d respectively in infiltrating water. Indigenous microbes pass a lag period of 37 d, and grow on aniline as the source of carbon in the RBF under denitrification conditions. Aniline concentration in leachate was lower than the detected limits, so its removal rate was 100 %. Total organic carbon (TOC) removal rates were 97.99 %, 91.39 % and 75.30 % for 40, 80 and 400 mg/L aniline concentrations respectively, based on TOC monitored in infiltrating water and leachate.

  6. Transport of bromide and pesticides through an undisturbed soil column: A modeling study with global optimization analysis

    Science.gov (United States)

    Dusek, Jaromir; Dohnal, Michal; Snehota, Michal; Sobotkova, Martina; Ray, Chittaranjan; Vogel, Tomas

    2015-04-01

    The fate of pesticides in tropical soils is still not understood as well as it is for soils in temperate regions. In this study, water flow and transport of bromide tracer and five pesticides (atrazine, imazaquin, sulfometuron methyl, S-metolachlor, and imidacloprid) through an undisturbed soil column of tropical Oxisol were analyzed using a one-dimensional numerical model. The numerical model is based on Richards' equation for solving water flow, and the advection-dispersion equation for solving solute transport. Data from a laboratory column leaching experiment were used in the uncertainty analysis using a global optimization methodology to evaluate the model's sensitivity to transport parameters. All pesticides were found to be relatively mobile (sorption distribution coefficients lower than 2 cm3 g- 1). Experimental data indicated significant non-conservative behavior of bromide tracer. All pesticides, with the exception of imidacloprid, were found less persistent (degradation half-lives smaller than 45 days). Three of the five pesticides (atrazine, sulfometuron methyl, and S-metolachlor) were better described by the linear kinetic sorption model, while the breakthrough curves of imazaquin and imidacloprid were more appropriately approximated using nonlinear instantaneous sorption. Sensitivity analysis suggested that the model is most sensitive to sorption distribution coefficient. The prediction limits contained most of the measured points of the experimental breakthrough curves, indicating adequate model concept and model structure for the description of transport processes in the soil column under study. Uncertainty analysis using a physically-based Monte Carlo modeling of pesticide fate and transport provides useful information for the evaluation of chemical leaching in Hawaii soils.

  7. Persistence and leaching potential of microorganisms and mineral N in animal manure applied to intact soil columns.

    Science.gov (United States)

    Amin, M G Mostofa; Forslund, Anita; Bui, Xuan Thanh; Juhler, René K; Petersen, Søren O; Lægdsmand, Mette

    2013-01-01

    Pathogens may reach agricultural soils through application of animal manure and thereby pose a risk of contaminating crops as well as surface and groundwater. Treatment and handling of manure for improved nutrient and odor management may also influence the amount and fate of manure-borne pathogens in the soil. A study was conducted to investigate the leaching potentials of a phage (Salmonella enterica serovar Typhimurium bacteriophage 28B) and two bacteria, Escherichia coli and Enterococcus species, in a liquid fraction of raw pig slurry obtained by solid-liquid separation of this slurry and in this liquid fraction after ozonation, when applied to intact soil columns by subsurface injection. We also compared leaching potentials of surface-applied and subsurface-injected raw slurry. The columns were exposed to irrigation events (3.5-h period at 10 mm h(-1)) after 1, 2, 3, and 4 weeks of incubation with collection of leachate. By the end of incubation, the distribution and survival of microorganisms in the soil of each treatment and in nonirrigated columns with injected raw slurry or liquid fraction were determined. E. coli in the leachates was quantified by both plate counts and quantitative PCR (qPCR) to assess the proportions of culturable and nonculturable (viable and nonviable) cells. Solid-liquid separation of slurry increased the redistribution in soil of contaminants in the liquid fraction compared to raw slurry, and the percent recovery of E. coli and Enterococcus species was higher for the liquid fraction than for raw slurry after the four leaching events. The liquid fraction also resulted in more leaching of all contaminants except Enterococcus species than did raw slurry. Ozonation reduced E. coli leaching only. Injection enhanced the leaching potential of the microorganisms investigated compared to surface application, probably because of a better survival with subsurface injection and a shorter leaching path.

  8. Mobility of arsenic, cadmium and zinc in a multi-element contaminated soil profile assessed by in-situ soil pore water sampling, column leaching and sequential extraction

    Energy Technology Data Exchange (ETDEWEB)

    Beesley, Luke, E-mail: l.beesley@2007.ljmu.ac.u [Faculty of Science, Liverpool John Moores University, Liverpool L3 3AF (United Kingdom); Moreno-Jimenez, Eduardo [Departamento de Quimica Agricola, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Clemente, Rafael [Dep. of Soil and Water Conservation and Organic Waste Management, CEBAS-CSIC, Campus Universitario de Espinardo, PO Box 164, 30100 Espinardo, Murcia (Spain); Lepp, Nicholas; Dickinson, Nicholas [Faculty of Science, Liverpool John Moores University, Liverpool L3 3AF (United Kingdom)

    2010-01-15

    Three methods for predicting element mobility in soils have been applied to an iron-rich soil, contaminated with arsenic, cadmium and zinc. Soils were collected from 0 to 30 cm, 30 to 70 cm and 70 to 100 cm depths in the field and soil pore water was collected at different depths from an adjacent 100 cm deep trench. Sequential extraction and a column leaching test in the laboratory were compared to element concentrations in pore water sampled directly from the field. Arsenic showed low extractability, low leachability and occurred at low concentrations in pore water samples. Cadmium and zinc were more labile and present in higher concentrations in pore water, increasing with soil depth. Pore water sampling gave the best indication of short term element mobility when field conditions were taken into account, but further extraction and leaching procedures produced a fuller picture of element dynamics, revealing highly labile Cd deep in the soil profile. - Mobility of arsenic, cadmium and zinc in a polluted soil can be realistically interpreted by in-situ soil pore water sampling.

  9. Soft soil strengthening by stone columns: case of the embankment under the bridge “Moulay Youssef” (Rabat/Salé

    Directory of Open Access Journals (Sweden)

    Nehab Noura

    2014-04-01

    Full Text Available The soil is generally a heterogeneous material presenting very variable characteristics. In a general way, the main problems related to soils are: low bearing capacity, deformations under static or dynamic loads, large displacements and large settlements of soft soil where the soil moves according to a fixed ground water table. The development of soil mechanics and geotechnical engineering has led to the amelioration of a wide range of soil improvement techniques. These techniques consist in modifying the characteristics of the ground by physical action or by incorporating columnar inclusions made of highly compacted gravel or granular material into the original soil. Stone column is one of the soft ground improvement methods, applicable to a wide range of soil strata and an economical method of support in compressible and cohesive soils. However, there are many difficulties in quantitative analysis of soil column interaction due to the fact that bearing capacity and consolidation behavior of stone column-mat foundation system is affected by various parameters. In the present study, mechanism and various parameters of stone column behavior are investigated by loading tests. Also, tests results are compared to the finite element numerical modeling “Plaxis 2D” (case study: the embankment under the bridge “Moulay Youssef, Rabat/Salé”.

  10. Method of Calculating the Freezing Rate of Single-Column Water-Permeable Soils (Metod Rascheta Skorosti Zamorazhivaniya Fil’Truyushchikh Gruntov Odinochnoy Kolonkoy),

    Science.gov (United States)

    1977-02-01

    calculating the freezing rate of homogeneous water-permeable soils by a single column; the method has been developed in works of B. V. Proskuryakov [1] and...ground volume freezes ; I. I L is the length of the freezing column; r is the radius of the frozen ground cylinder; r is time. B. V. Proskuryakov [1

  11. Modification of Spatial Distribution of 2,4-Dichlorophenoxyacetic Acid Degrader Microhabitats during Growth in Soil Columns

    Science.gov (United States)

    Pallud, C.; Dechesne, A.; Gaudet, J. P.; Debouzie, D.; Grundmann, G. L.

    2004-01-01

    Bacterial processes in soil, including biodegradation, require contact between bacteria and substrates. Knowledge of the three-dimensional spatial distribution of bacteria at the microscale is necessary to understand and predict such processes. Using a soil microsampling strategy combined with a mathematical spatial analysis, we studied the spatial distribution of 2,4-dichlorophenoxyacetic acid (2,4-D) degrader microhabitats as a function of 2,4-D degrader abundance. Soil columns that allowed natural flow were percolated with 2,4-D to increase the 2,4-D degrader abundance. Hundreds of soil microsamples (minimum diameter, 125 μm) were collected and transferred to culture medium to check for the presence of 2,4-D degraders. Spatial distributions of bacterial microhabitats were characterized by determining the average size of colonized soil patches and the average number of patches per gram of soil. The spatial distribution of 2,4-D degrader microhabitats was not affected by water flow, but there was an overall increase in colonized patch sizes after 2,4-D amendment; colonized microsamples were dispersed in the soil at low 2,4-D degrader densities and clustered in patches that were more than 0.5 mm in diameter at higher densities. During growth, spreading of 2,4-D degraders within the soil and an increase in 2,4-D degradation were observed. We hypothesized that spreading of the bacteria increased the probability of encounters with 2,4-D and resulted in better interception of the degradable substrate. This work showed that characterization of bacterial microscale spatial distribution is relevant to microbial ecology studies. It improved quantitative bacterial microhabitat description and suggested that sporadic movement of cells occurs. Furthermore, it offered perspectives for linking microbial function to the soil physicochemical environment. PMID:15128522

  12. Transporte do paclobutrazol em colunas de solos Paclobutrazol transport in soil columns

    Directory of Open Access Journals (Sweden)

    Mônica Lúcia Milfont

    2008-10-01

    reproductive capacity of the plant. This growth regulator remains active in the soil for several years being detrimental to subsequent tillage and contamination of groundwater through leaching. The objective of this work was to study the mechanisms involved in the transport and sorption of PBZ in an Ultisol and a Vertisol, both of the São Francisco Valley, Brazil. Column breakthrough experiments were performed with a water tracer (Bromide and with PBZ at 0.4 e 1.6 cm³.min-1 in the two soils. Hydrodispersive parameters of both soils were obtained by fitting the tracer breakthrough curves (BTC with the convection-dispersion (CDE model, whereas the parameters of PBZ reactive transport were obtained with the CDE-2 sorption sites model, through the CXTFIT code. PBZ presents a lower retardation factor in the Vertisol than in the Ultisol. The water flow was found to strongly affect PBZ mass balance, mainly because of sorption/desorption hysteresis, suggesting partial irreversible sorption of the chemical. The two sites model fitted well the tracer and PBZ breakthrough curves. The results showed that PBZ transport is strongly influenced by its interactions with the soil matrix through rate-limited sorption. The determined transport parameters indicate that PBZ applied to the two tropical soils cultivated with Mango presents an important leaching potential and contamination risk of the groundwater of the São Francisco Valley.

  13. Influence of soil structure on contaminant leaching from injected slurry.

    Science.gov (United States)

    Amin, M G Mostofa; Pedersen, Christina Østerballe; Forslund, Anita; Veith, Tamie L; Laegdsmand, Mette

    2016-12-15

    Animal manure application to agricultural land provides beneficial organic matter and nutrients but can spread harmful contaminants to the environment. Contamination of fresh produce, surface water and shallow groundwater with the manure-borne pollutants can be a critical concern. Leaching and persistence of nitrogen, microorganisms (bacteriophage, E. coli, and Enterococcus) and a group of steroid hormone (estrogens) were investigated after injection of swine slurry into either intact (structured) or disturbed (homogeneous repacked) soil. The slurry was injected into hexaplicate soil columns at a rate of 50 t ha(-1) and followed with four irrigation events: 3.5-h period at 10 mm h(-1) after 1, 2, 3, and 4 weeks. The disturbed columns delayed the leaching of a conservative tracer and microorganisms in the first irrigation event compared to the intact columns due to the effect of disturbed macropore flow paths. The slurry constituents that ended up in or near the macropore flow paths of the intact soil were presumably washed out relatively quickly in the first event. For the last three events the intact soil leached fewer microorganisms than the disturbed soil due to the bypassing effect of water through the macropore flow path in the intact soil. Estrogen leached from the intact soil in the first event only, but for the disturbed soil it was detected in the leachates of last two events also. Leaching from the later events was attributed to higher colloid transport from the disturbed soils. In contrast, NO3-N leaching from the intact soil was higher for all events except the first event, probably due to a lower nitrification rate in the disturbed soil. A week after the last irrigation event, the redistribution of all slurry constituents except NO3-N in most of the sections of the soil column was higher for the disturbed soil. Total recovery of E. coli was significantly higher from the disturbed soil and total leaching of mineral nitrogen was significantly lower

  14. A Nonlinear Solute Transport Model and Data Reconstruction with Parameter Determination in an Undisturbed Soil-Column Experiment

    Directory of Open Access Journals (Sweden)

    Gongsheng Li

    2011-01-01

    Full Text Available A real undisturbed soil-column infiltrating experiment in Zibo, Shandong, China, is investigated, and a nonlinear transport model for a solute ion penetrating through the column is put forward by using nonlinear Freundlich's adsorption isotherm. Since Freundlich's exponent and adsorption coefficient and source/sink terms in the model cannot be measured directly, an inverse problem of determining these parameters is encountered based on additional breakthrough data. Furthermore, an optimal perturbation regularization algorithm is introduced to determine the unknown parameters simultaneously. Numerical simulations are carried out and then the inversion algorithm is applied to solve the real inverse problem and reconstruct the measured data successfully. The computational results show that the nonlinear advection-dispersion equation discussed in this paper can be utilized by hydrogeologists to research solute transport behaviors with nonlinear adsorption in porous medium.

  15. Use of farming and agro-industrial wastes as versatile barriers in reducing pesticide leaching through soil columns.

    Science.gov (United States)

    Fenoll, J; Ruiz, E; Flores, P; Vela, N; Hellín, P; Navarro, S

    2011-03-15

    Increased interest has been recently focused on assessing the influence of the addition of organic wastes related to movement of pesticides in soils of low organic matter (OM) content. This study reports the effect of two different amendments, animal manure (composted sheep manure) and agro-industrial waste (spent coffee grounds) on the mobility of 10 pesticides commonly used for pepper protection on a clay-loam soil (OM = 0.22%). The tested compounds were azoxystrobin, cyprodinil, fludioxonil, hexaconazole, kresoxim-methyl, pyrimethanil, tebuconazole, and triadimenol (fungicides), pirimicarb (insecticide), and propyzamide (herbicide). Breakthrough curves were obtained from disturbed soil columns. Cumulative curves obtained from unamended soil show a leaching of all pesticides although in different proportions (12-65% of the total mass of compound applied), showing triadimenol and pirimicarb the higher leachability. Significant correlation (r = 0.93, psoils, pyrimethanil (soil amended with spent coffee grounds. A decrease in pesticide leaching was observed with the increase in dissolved organic matter (DOM) of leachates. The results obtained point to the interest in the use of organic wastes in reducing the pollution of groundwater by pesticide drainage.

  16. Transfer of reactive solutes in the unsaturated zone of soils at several observation scales; Transfert de solutes reactifs dans la zone non-saturee des sols a differentes echelles d'observation

    Energy Technology Data Exchange (ETDEWEB)

    Limousin, G

    2006-10-15

    The transfer of contaminants in the unsaturated zone of soils is driven by numerous mechanisms. Field studies are sometimes difficult to set up, and so the question is raised about the reliability of laboratory measurements for describing a field situation. The nuclear power plant at Brennilis (Finistere, France) has been chosen to study the transfer of strontium, cobalt and inert tracers in the soil of this industrial site. Several observation scales have been tested (batch, stirred flow-through reactor, sieved-soil column, un-repacked or repacked soil-core lysimeter, field experiments) in order to determine, at each scale, the factors that influence the transfer of these contaminants, then to verify the adequacy between the different observation scales and their field representativeness. Regarding the soil hydrodynamic properties, the porosity, the water content in the field, the pore water velocity at the water content in the field, the saturation hydraulic conductivity and the dispersion coefficient of this embanked soil are spatially less heterogeneous than those of agricultural or non-anthropic soils. The results obtained with lysimeter and field experiments suggest that hydrodynamics of this unstructured soil can be studied on a repacked sample if the volume is high compared to the rare big-size stones. Regarding the chemical soil-contaminant interactions, cobalt and strontium isotherms are non-linear at concentration higher than 10{sup -4} mol.L{sup -1}, cobalt adsorption and desorption are fast and independent on pH. On the contrary, at concentration lower than 3.5 x 10{sup -6} mol.L{sup -1}, cobalt and strontium isotherms are linear, cobalt desorption is markedly slower than adsorption and both cobalt partition coefficient at equilibrium and its reaction kinetics are highly pH-dependent. For both elements, the results obtained with batch, stirred flow-through reactor and sieved-soil column are in adequacy. However, strontium batch adsorption measurements

  17. The opposing effects of bacterial activity and gas production on anaerobic TCE degradation in soil columns.

    Science.gov (United States)

    Singhal, Naresh; Jaffé, Peter; Maier, Walter; Jho, Eun Hea

    2007-11-01

    This laboratory study explores the effect of growth substrate concentration on the anaerobic degradation of trichloroethylene (TCE) in sand packed columns. In all columns the growth substrate rapidly degraded to gas, that formed a separate phase. Biomass accumulated in the 0-4.8 cm section of the columns in proportion to the influent growth substrate concentration and biomass concentrations in the remaining sections of all columns were similar to the column receiving the lowest substrate concentration. Increases in growth substrate concentration up to 3030 mg-CODl(-1) promoted TCE degradation, but a further increase to 14300 mg-CODl(-1) reduced the amount of TCE completely dechlorinated but did not affect the production of chlorinated TCE intermediates. The mathematical model developed here satisfactorily described the enhancement in TCE dehalogenation for substrate concentration up to 3030 mg-CODl(-1); reproducing TCE dehalogenation for 14300 mg-CODl(-1) required that the moisture content used in simulation be lowered to 0.1. The study shows that volatilization of TCE can be significant and volatilization losses should be taken into account when anaerobic activity in in-situ bioremediation applications is stimulated via addition of growth substrates. An implication of the modeling simulations is that maintaining a lower, but uniform, substrate concentration over the contaminated region may lead to faster contaminant degradation.

  18. Water and dissolved carbon transport in an eroding soil landscape using column experiments

    DEFF Research Database (Denmark)

    Rieckh, Helene; Gerke, Horst; Glæsner, Nadia;

    2014-01-01

    boundary. Breakthrough curves for a pre-applied tracer (Br-) on the soil surface and a tracer applied with irrigation water (3H2O) were modeled analytically using CXTFIT. The heterogeneity of the Luvisol horizons was generally higher than that of the Regosol horizons, which relates to the higher......In the hummocky ground moraine soil landscape, a spatial continuum of more or less eroded soils developed from till under intensive agricultural cultivation. Water flow and solute transport are affected by the variable soil structural and pedological developments, which are posing a challenge...... for flux estimation. The objective of this study was to investigate transport of water, dissolved organic (DOC), and particulate carbon (PC) through soil profiles of an eroded Haplic Luvisol and a heavily eroded Haplic Regosol. We studied 5 soil horizons in three replicates each: Ap (0-20 cm) and E (20...

  19. Assessing tungsten transport in the vadose zone: from dissolution studies to soil columns.

    Science.gov (United States)

    Tuna, Gulsah Sen; Braida, Washington; Ogundipe, Adebayo; Strickland, David

    2012-03-01

    This study investigates the dissolution, sorption, leachability, and plant uptake of tungsten and alloying metals from canister round munitions in the presence of model, well characterized soils. The source of tungsten was canister round munitions, composed mainly of tungsten (95%) with iron and nickel making up the remaining fraction. Three soils were chosen for the lysimeter studies while four model soils were selected for the adsorption studies. Lysimeter soils were representatives of the typical range of soils across the continental USA; muck-peat, clay-loamy and sandy-quartzose soil. Adsorption equilibrium data on the four model soils were modeled with Langmuir and linear isotherms and the model parameters were obtained. The adsorption affinity of soils for tungsten follows the order: Pahokee peat>kaolinite>montmorillonite>illite. A canister round munition dissolution study was also performed. After 24 d, the measured dissolved concentrations were: 61.97, 3.56, 15.83 mg L(-1) for tungsten, iron and nickel, respectively. Lysimeter transport studies show muck peat and sandy quartzose soils having higher tungsten concentration, up to 150 mg kg(-1) in the upper layers of the lysimeters and a sharp decline with depth suggesting strong retardation processes along the soil profile. The concentrations of tungsten, iron and nickel in soil lysimeter effluents were very low in terms of posing any environmental concern; although no regulatory limits have been established for tungsten in natural waters. The substantial uptake of tungsten and nickel by ryegrass after 120 d of exposure to soils containing canister round munition suggests the possibility of tungsten and nickel entering the food chain.

  20. Effects of pulsed and oscillatory flow on water vapor removal from a laboratory soil column. Final report, November 1993

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, K.E.

    1993-05-01

    Subsurface contamination by volatile organic contaminants (VOC`s) in the vadose zone and groundwater is primarily due to leaking underground storage tanks and industrial spills. Soil vapor extraction is a technique that is being used successfully to remove VOC`s from the subsurface. A flow of air is established through the soil to remove the vapor phase component of the contaminant. Soil vapor extraction will initially remove high levels of contaminant that is already present in the macropores. The concentration will start to decline as the removal from the soil matrix becomes limited by diffusion of contaminant from regions away from the air flow paths. This study examines potential methods of overcoming the diffusion limitation by adding an oscillatory component to the steady air flow and by pulsed flow, which involves turning air flow on and off at predetermined intervals. The study considered only the removal of water from the soil to try to establish general vapor behavior in the soil under the imposed conditions. Based on a statistical analysis, both the oscillatory and pulsed flow showed an improved water removal rate over the steady state flow. The effect of oscillatory flow was only examined at higher frequencies. The literature indicates that oscillations at lower frequencies may be more effective. Pulsed flow showed the most efficient removal of water compared to steady state conditions. The pulsed flow was most efficient because rather than reducing the diffusion limitation, the system would shut down and wait for diffusion to occur. This optimizes energy consumption, but does not reduce treatment time. The oscillatory flow actually reduced the diffusion limitation within the column which could result in a shorter treatment time.

  1. Transport of sewage molecular markers through saturated soil column and effect of easily biodegradable primary substrate on their removal.

    Science.gov (United States)

    Foolad, Mahsa; Ong, Say Leong; Hu, Jiangyong

    2015-11-01

    Pharmaceutical and personal care products (PPCPs) and artificial sweeteners (ASs) are emerging organic contaminants (EOCs) in the aquatic environment. The presence of PPCPs and ASs in water bodies has an ecologic potential risk and health concern. Therefore, it is needed to detect the pollution sources by understanding the transport behavior of sewage molecular markers in a subsurface area. The aim of this study was to evaluate transport of nine selected molecular markers through saturated soil column experiments. The selected sewage molecular markers in this study were six PPCPs including acetaminophen (ACT), carbamazepine (CBZ), caffeine (CF), crotamiton (CTMT), diethyltoluamide (DEET), salicylic acid (SA) and three ASs including acesulfame (ACF), cyclamate (CYC), and saccharine (SAC). Results confirmed that ACF, CBZ, CTMT, CYC and SAC were suitable to be used as sewage molecular markers since they were almost stable against sorption and biodegradation process during soil column experiments. In contrast, transport of ACT, CF and DEET were limited by both sorption and biodegradation processes and 100% removal efficiency was achieved in the biotic column. Moreover, in this study the effect of different acetate concentration (0-100mg/L) as an easily biodegradable primary substrate on a removal of PPCPs and ASs was also studied. Results showed a negative correlation (r(2)>0.75) between the removal of some selected sewage chemical markers including ACF, CF, ACT, CYC, SAC and acetate concentration. CTMT also decreased with the addition of acetate, but increasing acetate concentration did not affect on its removal. CBZ and DEET removal were not dependent on the presence of acetate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Autoclave treatment of pig manure does not reduce the risk of transmission and transfer of tetracycline resistance genes in soil: successive determinations with soil column experiments.

    Science.gov (United States)

    Kang, Yijun; Gu, Xian; Hao, Yangyang; Hu, Jian

    2016-03-01

    The increasing use of antibiotics, especially tetracycline, in livestock feed adversely affects animal health and ecological integrity. Therefore, approaches to decrease this risk are urgently needed. High temperatures facilitate antibiotic degradation; whether this reduces transmission risk and transfer of tetracycline-resistant bacteria (TRBs) and tetracycline resistance genes (TRGs) in soil remains unknown. Successive experiments with soil columns evaluated the effects of autoclaving pig manure (APM) on soil TRB populations and TRGs over time at different soil depths. The data showed sharp increases in TRB populations and TRGs in each subsoil layer of PM (non-APM) and APM treatments within 30 days, indicating that TRBs and TRGs transferred rapidly. The level of TRBs in the upper soil layers was approximately 15-fold higher than in subsoils. TRBs were not dependent on PM and APM levels, especially in the late phase. Nevertheless, higher levels of APM led to rapid expansion of TRBs as compared to PM. Moreover, temporal changes in TRB frequencies in total culturable bacteria (TCBs) were similar to TRBs, indicating that the impact of PM or APM on TRBs was more obvious than for TCBs. TRBs were hypothesized to depend on the numbers of TRGs and indigenous recipient bacteria. In the plough layer, five TRGs (tetB, tetG, tetM, tetW, and tetB/P) existed in each treatment within 150 days. Selective pressure of TC may not be a necessary condition for the transfer and persistence of TRGs in soil. High temperatures might reduce TRBs in PM, which had minimal impact on the transmission and transfer of TRGs in soil. Identifying alternatives to decrease TRG transmission remains a major challenge.

  3. VAPOR PHASE TREATMENT OF PCE IN A SOIL COLUMN BY LAB-SCALE ANAEROBIC BIOVENTING

    Science.gov (United States)

    Microbial destruction of highly chlorinated organic compounds must be initiated by anaerobic followed by aerobic dechlorination. In-situ dechlorination of vadose zone soil contaminated with these compounds requires, among other factors, the establishment of highly reductive anaer...

  4. Retention of pesticides in sandy soil columns modified with a wood barrier

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Martin, M. J.; Rodriguez-Cruz, M. S.; Ordax, J. M.; Arienzo, M.

    2009-07-01

    Wood residues can be used as low-cost potential sorbents of hydrophobic pesticides in technologies aimed to prevent soil and water contamination and reduce the risk of environmental pollution produced by point pollution sources of these compounds. The objective of this work was to study the effect of a pine or oak sawdust barrier on the retention of Iinuron, alachlor and metalaxyl, with different hydrophobic character, in a sandy soil. (Author)

  5. Flow of microemulsion through soil columns contaminated with asphaltic residue; Fluxo de microemulsoes atraves do solo contaminado com residuos asfalticos

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Marcia C.K.; Oliveira, Jose F. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE); Oliveira, Roberto C.G.; Gonzalez, Gazpar [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2004-07-01

    Nowadays, soil contamination with nonaqueous phase liquids (NAPLs) such as petroleum hydrocarbons is a major environmental problem. Significant efforts have been devoted to the development of processes to remediate sites contaminated with NAPLs. Unfortunately, most of the developed processes proved to be inefficient to remove the organic heavy fraction present in the NAPLs. Nevertheless, in our preliminary bench scale tests it was observed that, due to their high solubilization capacity and stability, microemulsions are able to remove organic heavy fractions like asphaltenes and resins, typically present in crude oils. The present work was dimensioned to evaluate, under up-flow condition, the performance of different microemulsions specially designed to remove asphaltenes fractions from soils using a column test set-up. The contaminant residual concentration was quantified by UV spectroscopy and the microemulsion efficiency determined using mass balance. The results showed that the microemulsions tested have a high capacity for removing asphaltenes fractions from contaminated soils. It was also observed that the predominant removal mechanism, solubilization or mobilization, depends essentially on the microemulsion's chemical formulation. Finally it was verified that microemulsion's formulations based on natural solvents compounds are also efficient for removing asphaltic residues. (author)

  6. Use of hydrophilic polymers from diapers to aid the establishment of Spergularia purpurea in a mine soil.

    Science.gov (United States)

    Qu, G; de Varennes, A

    2010-06-15

    We used hydrophilic polymers from diapers to aid the establishment of an indigenous plant (Spergularia purpurea (Persoon) G. Don fil.) in a soil from a pyrite mine. Lysimeters were filled with the mine soil with no amendment (control), with a polyacrylate polymer, with a polymer removed from diapers, and with shredded diapers. The establishment of a plant cover was faster in soil amended with polymer from diapers, and 85 days after sowing the soil was completely covered in all treatments except control. The concentrations of trace elements in plant shoots decreased in amended soil. The activities of soil acid phosphatase, beta-glucosidase, protease and cellulase were greatest in soil amended with the polyacrylate polymer or with polymer removed from diapers, while the application of shredded diapers leads to values that were in general intermediate between these treatments and unamended control. Basal- and substrate-induced respirations, and dehydrogenase were greatest in soil amended with polymers, but the presence of a plastic film and fibrous materials from shredded diapers prevented any improvement in these parameters compared with unamended soil. In the second experiment, we evaluated the risk of downward movement of polymers in columns of a sandy soil. Polymer from diapers, with or without Cu, was placed at a 10 cm-depth. Five leaching cycles with artificial rain took place and leachates were analyzed for organic matter and Cu. At the end of the experiment, the soil columns were sliced and each layer was analyzed separately. Some repacking of soil and polymer particles took place, but there was no indication that polymers moved to any great depth in soil columns.

  7. Geophysical surveys combined with laboratory soil column experiments to identify and explore risk areas for soil and water pollution in feedlots

    Science.gov (United States)

    Espejo-Pérez, Antonio Jesus; Sainato, Claudia Mabel; Jairo Márquez-Molina, John; Giráldez, Juan Vicente; Vanderlinden, Karl

    2014-05-01

    Changes of land use without a correct planning may produce its deterioration with their social, economical and environmental irreversible consequences over short to medium time range. In Argentina, the expansion of soybean fields induced a reduction of the area of pastures dedicated to stockbreeding. As cattle activity is being progressively concentrated on small pens, at feedlots farms, problems of soil and water pollution, mainly by nitrate, have been detected. The characterization of the spatial and temporal variability of soil water content is very important because the mostly advective transport of solutes. To avoid intensive soil samplings, very expensive, one has to recur to geophysical exploration methods. The objective of this work was to identify risk areas within a feedlot of the NW zone of Buenos Aires Province, in Argentina through geophysical methods. The surveys were carried out with an electromagnetic induction profiler EMI-400 (GSSI) and a Time domain Reflectometry (TDR) survey of depth 0-0.10 m with soil sampling and measurement of moisture content with gravimetric method (0-1.0 m). Several trenches were dug inside the pens and also at a test site, where texture, apparent density, saturated hydraulic conductivity (Ks), electrical conductivity of the saturation paste extract and organic matter content (OM) were measured. The water retention curves for these soils were also determined. At one of the pens undisturbed soil columns were extracted at 3 locations. Laboratory analysis for 0-1.0 m indicated that soil texture was classified as sandy loam, average organic matter content (OM) was greater than 2.3% with low values of apparent density in the first 10 cm. The range of spatial dependence of data suggested that the number of soil samples could be reduced. Soil apparent electrical conductivity (ECa) and soil moisture were well correlated and indicated a clear spatial pattern in the corrals. TDR performance was acceptable to identify the spatial

  8. Predicting recovery from acid rain using the micro-spatial heterogeneity of soil columns downhill the infiltration zone of beech stemflow: introduction of a hypothesis.

    Science.gov (United States)

    Berger, Torsten W; Muras, Alexander

    Release of stored sulfur may delay the recovery of soil pH from Acid Rain. It is hypothesized that analyzing the micro-spatial heterogeneity of soil columns downhill of a beech stem enables predictions of soil recovery as a function of historic acid loads and time. We demonstrated in a very simplified approach, how these two different factors may be untangled from each other using synthetic data. Thereafter, we evaluated the stated hypothesis based upon chemical soil data with increasing distance from the stem of beech trees. It is predicted that the top soil will recover from acid deposition, as already recorded in the infiltration zone of stemflow near the base of the stem. However, in the between trees areas and especially in deeper soil horizons recovery may be highly delayed.

  9. Influence of a compost layer on the attenuation of 28 selected organic micropollutants under realistic soil aquifer treatment conditions: insights from a large scale column experiment.

    Science.gov (United States)

    Schaffer, Mario; Kröger, Kerrin Franziska; Nödler, Karsten; Ayora, Carlos; Carrera, Jesús; Hernández, Marta; Licha, Tobias

    2015-05-01

    Soil aquifer treatment is widely applied to improve the quality of treated wastewater in its reuse as alternative source of water. To gain a deeper understanding of the fate of thereby introduced organic micropollutants, the attenuation of 28 compounds was investigated in column experiments using two large scale column systems in duplicate. The influence of increasing proportions of solid organic matter (0.04% vs. 0.17%) and decreasing redox potentials (denitrification vs. iron reduction) was studied by introducing a layer of compost. Secondary effluent from a wastewater treatment plant was used as water matrix for simulating soil aquifer treatment. For neutral and anionic compounds, sorption generally increases with the compound hydrophobicity and the solid organic matter in the column system. Organic cations showed the highest attenuation. Among them, breakthroughs were only registered for the cationic beta-blockers atenolol and metoprolol. An enhanced degradation in the columns with organic infiltration layer was observed for the majority of the compounds, suggesting an improved degradation for higher levels of biodegradable dissolved organic carbon. Solely the degradation of sulfamethoxazole could clearly be attributed to redox effects (when reaching iron reducing conditions). The study provides valuable insights into the attenuation potential for a wide spectrum of organic micropollutants under realistic soil aquifer treatment conditions. Furthermore, the introduction of the compost layer generally showed positive effects on the removal of compounds preferentially degraded under reducing conditions and also increases the residence times in the soil aquifer treatment system via sorption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Comparison of batch, stirred flow chamber, and column experiments to study adsorption, desorption and transport of carbofuran within two acidic soils.

    Science.gov (United States)

    Bermúdez-Couso, Alipio; Fernández-Calviño, David; Rodríguez-Salgado, Isabel; Nóvoa-Muñoz, Juan Carlos; Arias-Estévez, Manuel

    2012-06-01

    Different methods (batch, column and stirred flow chamber experiments) used for adsorption and desorption of carbofuran studies were compared. All tested methods showed that the carbofuran adsorption was higher in the soil with the higher organic matter content, whereas the opposite behaviour was observed for the percentage of carbofuran desorbed. However, different methods have revealed some discrepancies in carbofuran adsorption/desorption kinetics. Although batch method showed interesting data on equilibrium experiments, such as a low heterogeneity for the carbofuran adsorption sites independent of soil organic matter content, it had some disadvantages for carbofuran adsorption/desorption kinetic studies. The disadvantages were related with the excessive limitations of this method on kinetics, i.e., no difference could be detected between different soils. However, with column and stirred flow chamber methods the carbofuran adsorption/desorption kinetics of different soils could be compared. Moreover, the absolute values of carbofuran adsorption/desorption and its rate were higher in the stirred flow chamber than in the batch and column experiments. Using stirred flow chamber experiments the carbofuran desorption was significantly faster than its adsorption, whereas carbofuran using column experiments they were similar. These discrepancies should be considered when the results obtained only with one method is discussed.

  11. Monod kinetics rather than a first-order degradation model explains atrazine fate in soil mini-columns: implications for pesticide fate modelling.

    Science.gov (United States)

    Cheyns, K; Mertens, J; Diels, J; Smolders, E; Springael, D

    2010-05-01

    Pesticide transport models commonly assume first-order pesticide degradation kinetics for describing reactive transport in soil. This assumption was assessed in mini-column studies with associated batch degradation tests. Soil mini-columns were irrigated with atrazine in two intermittent steps of about 30 days separated by 161 days application of artificial rain water. Atrazine concentration in the effluent peaked to that of the influent concentration after initial break-through but sharply decreased while influx was sustained, suggesting a degradation lag phase. The same pattern was displayed in the second step but peak height and percentage of atrazine recovered in the effluent were lower. A Monod model with biomass decay was successfully calibrated to this data. The model was successfully evaluated against batch degradation data and mini-column experiments at lower flow rate. The study suggested that first-order degradation models may underestimate risk of pesticide leaching if the pesticide degradation potential needs amplification during degradation.

  12. Modeling Stone Columns

    Directory of Open Access Journals (Sweden)

    Jorge Castro

    2017-07-01

    Full Text Available 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.

  13. Modeling Stone Columns

    Science.gov (United States)

    2017-01-01

    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. PMID:28773146

  14. Effect of pore water velocities and solute input methods on chloride transport in the undisturbed soil columns of Loess Plateau

    Science.gov (United States)

    Zhou, BeiBei; Wang, QuanJiu

    2016-04-01

    Studies on solute transport under different pore water velocity and solute input methods in undisturbed soil could play instructive roles for crop production. Based on the experiments in the laboratory, the effect of solute input methods with small pulse input and large pulse input, as well as four pore water velocities, on chloride transport in the undisturbed soil columns obtained from the Loess Plateau under controlled condition was studied. Chloride breakthrough curves (BTCs) were generated using the miscible displacement method under water-saturated, steady flow conditions. Using the 0.15 mol L-1 CaCl2 solution as a tracer, a small pulse (0.1 pore volumes) was first induced, and then, after all the solution was wash off, a large pulse (0.5 pore volumes) was conducted. The convection-dispersion equation (CDE) and the two-region model (T-R) were used to describe the BTCs, and their prediction accuracies and fitted parameters were compared as well. All the BTCs obtained for the different input methods and the four pore water velocities were all smooth. However, the shapes of the BTCs varied greatly; small pulse inputs resulted in more rapid attainment of peak values that appeared earlier with increases in pore water velocity, whereas large pulse inputs resulted in an opposite trend. Both models could fit the experimental data well, but the prediction accuracy of the T-R was better. The values of the dispersivity, λ, calculated from the dispersion coefficient obtained from the CDE were about one order of magnitude larger than those calculated from the dispersion coefficient given by the T-R, but the calculated Peclet number, Pe, was lower. The mobile-immobile partition coefficient, β, decreased, while the mass exchange coefficient increased with increases in pore water velocity.

  15. Continuous-flow fractionation of selenium in contaminated sediment and soil samples using rotating coiled column and microcolumn extraction.

    Science.gov (United States)

    Savonina, Elena Yu; Fedotov, Petr S; Wennrich, Rainer

    2012-01-15

    Dynamic fractionation is considered to be an attractive alternative to conventional batch sequential extraction procedures for partitioning of trace metals and metalloids in environmental solid samples. This paper reports the first results on the continuous-flow dynamic fractionation of selenium using two different extraction systems, a microcolumn (MC) packed with the solid sample and a rotating coiled column (RCC) in which the particulate matter is retained under the action of centrifugal forces. The eluents (leachants) were applied in correspondence with a four-step sequential extraction scheme for selenium addressing "soluble", "adsorbed", "organically bound", and "elemental" Se fractions extractable by distilled water, phosphate buffer, tetramethylammonium hydroxide, and sodium sulphite solutions, respectively. Selenium was determined in the effluent by using an inductively coupled plasma atomic emission spectrometer. Contaminated creek sediment and dumped waste (soil) samples from the abandoned mining area were used to evaluate resemblances and discrepancies of two continuous-flow methods for Se fractionation. In general, similar trends were found for Se distribution between extractable and residual fractions. However, for the dumped waste sample which is rich in organic matter, the extraction in RCC provided more effective recovery of environmentally relevant Se forms (the first three leachable fractions). The most evident deviation was observed for "adsorbed" Se (recoveries by RCC and MC are 43 and 7 mg kg(-1), respectively). The data obtained were correlated with peculiarities of samples under investigation and operational principles of RCC and MC.

  16. Transport and survival of Cryptosporidium parvum oocysts in soil columns following applications of raw and separated liquid slurry

    DEFF Research Database (Denmark)

    Petersen, Heidi H.; Enemark, Heidi; Olsen, Annette;

    The widespread waterborne pathogen Cryptosporidium parvum is frequently transmitted to humans via contaminated drinking and recreational water. Nearly all drinking water in Denmark is groundwater, which can be contaminated with oocysts e.g. from application of contaminated manure to the field....... Oocysts transport to groundwater requires that the oocysts are transported through soil and bedrock to the water table. The purpose of this study was to determine the potential transport of the protozoan pathogen C. parvum through soil to land drains and, subsequently water sources in a laboratory setup...... using simulated rainfall and six 20 cm long replicate intact soil columns. Two types of contaminated slurry: raw slurry and the separated liquid fraction of the slurry were applied ten cm into the soil, which was subsequently irrigated once a week over a four-week period. C. parvum oocysts were detected...

  17. Influence of the DMPP (3,4-dimethyl pyrazole phosphate) on nitrogen transformation and leaching in multi-layer soil columns.

    Science.gov (United States)

    Yu, Qiao-Gang; Chen, Ying-Xu; Ye, Xue-Zhu; Tian, Guang-Ming; Zhang, Zhi-Jian

    2007-10-01

    The application of nitrogen fertilizers leads to various ecological problems such as nitrate leaching. The use of nitrification inhibitors as nitrate leaching retardants is a proposal that has been suggested for inclusion in regulations in many countries. In this study, using a multi-layer soil column device, the influence of new nitrification inhibitor DMPP (3,4-dimethyl pyrazole phosphate) was studied for understanding the nitrogen vertical transformation and lowering the nitrate leaching at different soil profile depths. The results indicated that, within 60 d of experiment, the regular urea added 1.0% DMPP can effectively inhibit the ammonium oxidation in the soil, and improve the ammonium concentration in soil solution over the 20cm depths of soil profile, while decline the concentrations of nitrate and nitrite. No obvious difference was found on ammonium concentrations in soil solution collected from deep profile under 20cm depths between regular urea and the urea added 1.0% DMPP. There was also no significant difference for the nitrate, ammonium and nitrite concentrations in the soil solution under 40cm depths of soil profile with the increasing nitrogen application level, among the treatments of urea added 1.0% DMPP within 60 d. It is proposed that DMPP could be used as an effective nitrification inhibitor in some region to control ammonium oxidation and decline the ion-nitrogen leaching, minimizing the shallow groundwater pollution risk and being beneficial for the ecological environment.

  18. The effect of feed water dissolved organic carbon concentration and composition on organic micropollutant removal and microbial diversity in soil columns simulating river bank filtration.

    Science.gov (United States)

    Bertelkamp, C; van der Hoek, J P; Schoutteten, K; Hulpiau, L; Vanhaecke, L; Vanden Bussche, J; Cabo, A J; Callewaert, C; Boon, N; Löwenberg, J; Singhal, N; Verliefde, A R D

    2016-02-01

    This study investigated organic micropollutant (OMP) biodegradation rates in laboratory-scale soil columns simulating river bank filtration (RBF) processes. The dosed OMP mixture consisted of 11 pharmaceuticals, 6 herbicides, 2 insecticides and 1 solvent. Columns were filled with soil from a RBF site and were fed with four different organic carbon fractions (hydrophilic, hydrophobic, transphilic and river water organic matter (RWOM)). Additionally, the effect of a short-term OMP/dissolved organic carbon (DOC) shock-load (e.g. quadrupling the OMP concentrations and doubling the DOC concentration) on OMP biodegradation rates was investigated to assess the resilience of RBF systems. The results obtained in this study imply that - in contrast to what is observed for managed aquifer recharge systems operating on wastewater effluent - OMP biodegradation rates are not affected by the type of organic carbon fraction fed to the soil column, in case of stable operation. No effect of a short-term DOC shock-load on OMP biodegradation rates between the different organic carbon fractions was observed. This means that the RBF site simulated in this study is resilient towards transient higher DOC concentrations in the river water. However, a temporary OMP shock-load affected OMP biodegradation rates observed for the columns fed with the river water organic matter (RWOM) and the hydrophilic fraction of the river water organic matter. These different biodegradation rates did not correlate with any of the parameters investigated in this study (cellular adenosine triphosphate (cATP), DOC removal, specific ultraviolet absorbance (SUVA), richness/evenness of the soil microbial population or OMP category (hydrophobicity/charge).

  19. Simultaneous determination of iodide and iodate in soil solution samples by HPLC with electrochemical detection and post-column reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Akira; Takaku, Yuichi; Hisamatsu, Shun' ichi [Department of Radioecology, Institute for Environmental Sciences, Aomori 039-3212 (Japan); Tsukada, Hirofumi [Department of Radioecology, Institute for Environmental Sciences, Aomori 039-3212 (Japan); Institute of Environmental Radioactivity, Fukushima University, Fukushima 960-1196 (Japan)

    2014-07-01

    Iodine-129 (half-life 1.6 x 10{sup 7} y) discharged into the atmosphere from nuclear facilities (e.g., a nuclear fuel reprocessing plant) is partly deposited on land and introduced into soil. Stable iodine ({sup 127}I) can be used as a natural analogue to predict the long-term behavior of {sup 129}I in the terrestrial environment. Iodine in soil mainly exists as I{sup -}, IO{sub 3}{sup -}, and organic iodine. Because the mobilities of these species in soil are quite different, iodine speciation in soil solution is a key for predicting the behavior of iodine in soil. We developed a new speciation method suitable for routine analysis of many soil solution samples, and successfully applied the method to real samples. The method involves determining the concentration of total iodine and then separately measuring the I{sup -} and IO{sub 3}{sup -} concentrations with an HPLC system. The HPLC system (Nano-space SI-2; Shiseido, Tokyo, Japan) consisted of a UV/Vis spectrometer and an electrochemical (amperometric) detector (50 mV Ag/AgCl). Two reverse-phase columns (2.0 x 50 mm Capcel Pak DD C8 and 2.0 x 250 mm Capcel Pak MGII C18; Shiseido) were serially connected, and a switching valve was set between them. I{sup -} and IO{sub 3}{sup -} in the sample solution were separated from each other in the DD C8 column. IO{sub 3}{sup -} eluted first from the column, while I{sup -} was retained. After IO{sub 3}{sup -} was further separated from other halogen acids with the C18 column, IO{sub 3}{sup -} was reacted with KBr and o-dianisidine in a thermos-reactor (90 deg. C), and absorption at 450 nm was measured with the UV/Vis spectrometer. The concentration of I{sup -} eluted from the first column was determined with the electrochemical detector. To determine the concentration of total iodine in the sample solution, organic iodine was decomposed by UV irradiation (UV digester 705; Metrohm AG, Herisau, Switzerland) for 30 min at 20 deg. C. The iodine in the solution was reduced to I

  20. Leachability of volatile fuel compounds from contaminated soils and the effect of plant exudates: A comparison of column and batch leaching tests.

    Science.gov (United States)

    Balseiro-Romero, María; Kidd, Petra S; Monterroso, Carmen

    2016-03-05

    Volatile fuel compounds such as fuel oxygenates (FO) (MTBE and ETBE) and BTEX (benzene, toluene, ethylbenzene and xylene) are some of the most soluble components of fuel. Characterizing the leaching potential of these compounds is essential for predicting their mobility through the soil profile and assessing the risk of groundwater contamination. Plant root exudates can play an important role in the modification of contaminant mobility in soil-plant systems, and such effects should also be considered in leaching studies. Artificially spiked samples of A and B horizons from an alumi-umbric Cambisol were leached in packed-columns and batch experiments using Milli-Q water and plant root exudates as leaching agents. The leaching potential and rate were strongly influenced by soil-contaminant interactions and by the presence of root exudates. Organic matter in A horizon preferably sorbed the most non-polar contaminants, lowering their leaching potential, and this effect was enhanced by the presence of root exudates. On the other hand, the inorganic components of the B horizon, showed a greater affinity for polar molecules, and the presence of root exudates enhanced the desorption of the contaminants. Column experiments resulted in a more realistic protocol than batch tests for predicting the leaching potential of volatile organic compounds in dissimilar soils.

  1. Soil-Gas Phase Transport and Structure Parameters for a Soil Under Different Management Regimes and at Two Moisture Levels

    DEFF Research Database (Denmark)

    Eden, Marie; Møldrup, Per; Schjønning, Per

    2012-01-01

    saturation and drainage to - 100 cm of matric potential (pF2). Gas diffusivity in intact samples at fm conditions exhibited a general, linear relationship with air-filled porosity (epsilon), independent of soil texture and treatment. Comparing intact and repacked samples drained to pF2, repacked soil......Measurements of diffusive and convective gas transport parameters can be used to describe soil functional architecture and reveal key factors for soil structure development. Undisturbed 100-cm(3) soil samples were sampled at the Long-term Research on Agricultural Systems experiment located...... at the University of California, Davis. The 18 plots used in this study represented fairly wide ranges in organic carbon (0. 0072-0.0153 kg kg(-1)) and clay (0.30-0.44 kg kg(-1)). Soil-air permeability, k(a), and soil-gas diffusivity, D-P/D-0, were determined at field-moist conditions (fin) and, subsequently, after...

  2. Soil column simulation experiment of remediating soil contaminated by diesel using bioventing technology%生物通风技术修复柴油污染土壤的土柱模拟实验

    Institute of Scientific and Technical Information of China (English)

    杨金凤; 陈鸿汉; 王春艳; 杨正礼

    2012-01-01

    Bioventing is an in situ forced oxidative soil remediation technology which combines soil vapor extraction with biodegradation.It has broad application prospects of soil contamination caused by underground storage tank leakage.In this paper,soil column experiment,which was used to simulate diesel contamination,was conducted.The law of balance distribution of residual TPH at different times and the change of diesel quantity in soil at different depths,together with total diesel quantity of the whole column were analyzed.The results showed that:(1) The profile distribution difference of residual TPH was influenced largerly by the initial loading conditions of soil column.(2) The diesel in soil was removed mainly by volatilization and biological degradation for the column which the balance distribution curves of residual TPH was bimodal.(3) Volatilization was mainly influenced by pore volume number during soil venting and soil moisture content,and gravity was mainly influenced by initial diesel concentration,soil moisture content and the ratio of carbon,nitrogen and phosphate.In addition to venting mode,the other factors affect the biodegradation.(4) For the soil column 8 and 11,which the initial diesel concentration were higher and the soil moisture content were both less,the biodegradation was the most significant and the removal effect of diesel in soil column was the best.The results could provide a theoretical basis for the enhancement of bioventing process.%生物通风技术是将土壤气相抽提和生物降解结合起来的原位强迫氧化降解方法,对于修复因地下储油罐泄漏引起的土壤污染具有广阔的应用前景。通过室内土柱模拟柴油泄漏污染土壤,分析了不同历时残余总石油烃(total pe-troleum hydrocarbon,TPH)的平衡分布规律以及土壤中不同深度柴油量、总柴油量的变化。结果表明:(1)各柱残余TPH剖面分布差异的原因受土柱的初始

  3. How to upscale the coupling between hydrology and vegetation at the hillslope scale with an equivalent soil-vegetation column model

    Science.gov (United States)

    Maquin, Mathilde; Mugler, Claude; Mouche, Emmanuel; Ducharne, Agnès

    2014-05-01

    Three-dimensional watershed models coupled with land surface models have demonstrated the control of soil moisture over land energy fluxes, as evaporation and transpiration (Maxwell and Kollet, Nature Geoscience, 2008; Condon et al., Advances in Water Resources, 2013). However, due to computational costs, these fully integrated watershed models cannot be used at larger scales. Upscaling hydrological models can be an alternative to take into account the impact of groundwater hydrology on land energy fluxes at various scales. In this purpose, we propose a two-step upscaling methodology aiming to replace a hillslope model by an equivalent vertical soil column model suitable for land surface modelling. The hillslope reference model is based on a two-dimensional aquifer model (resolution of Richards' equation) combined with a representation of vegetation and climate forcing as boundary condition. In this system, two main hydrological processes corresponding to different time scales have to be distinguished: the vertical water transfer from roots to the atmosphere through the vegetation, and the longitudinal flow of the aquifer to the stream. In an upscaling approach, two options can be considered: one may accurately model the aquifer longitudinal flow but with a degraded model of vertical transfer, or inversely give a preferential treatment to the vertical flow. As the exchanges between soil, vegetation and atmosphere are strongly dependent on the vertical profile of water (through the distribution of roots), the second option appears to be more adapted to our objective which is the assessment of hillslope hydrology on land surface fluxes. In the first step of our upscaling methodology, the two-dimensional reference hillslope is modelled as a set of one-dimensional independent vertical soil vegetation columns. In each of them, Richards' equation is solved in the vertical direction, the representation of roots and climate forcing remaining unchanged. Moreover, a sink

  4. Effect of pH on transport of Pb2+, Mn2+, Zn2+ and Ni2+ through lateritic soil: Column experiments and transport modeling

    Institute of Scientific and Technical Information of China (English)

    Srilert Chotpantarat; Say Kee Ong; Chakkaphan Sutthirat; Khemarath Osathaphan

    2011-01-01

    This study investigated the effects of pH on the transport of Pb2+, Mn2+, Zn2+ and Ni2+ through lateritic soil columns.Model results by fitting the symmetric breakthrough curves (BTCs) of bromide (Br-) with CXTFIT model suggested that physical non-equilibrium processes were absent in the columns.The heavy metal BTCs were, however, asymmetrical and exhibited a tailing phenomenon,indicating the presence of chemical non-equilibrium processes in the columns.The retardation factors of Pb2+ were the largest of the four metal ions at both pH 4.0 (33.3) and pH 5.0 (35.4).The use of Langmuir isotherm parameters from batch studies with HYDRUS-1D did not predict the BTCs well.Rather the two-site model (TSM) described the heavy metal BTCs better than the equilibrium linear/nonlinear Langmuir model.The fraction of instantaneous sorption sites (f) of all four metal ions on the lateritic soil was consistently about 30%-44% of the total sorption sites.

  5. Dolomite phosphate rock (DPR) application in acidic sandy soil in reducing leaching of phosphorus and heavy metals-a column leaching study.

    Science.gov (United States)

    Yang, Yuangen; He, Zhenli; Yang, Xiaoe; Stoffella, Peter J

    2013-06-01

    A column leaching study was designed to investigate the leaching potential of phosphorus (P) and heavy metals from acidic sandy soils applied with dolomite phosphate rock (DPR) fertilizers containing varying amounts of DPR material and N-Viro soils. DPR fertilizers were made from DPR materials mixing with N-Viro soils at the ratios of 30, 40, 50, 60, and 70 %, and applied in acidic sandy soils at the level of 100 mg available P per kilogram soil. A control and a soluble P chemical fertilizer were also included. The amended soils were incubated at room temperature with 70 % field water holding capacity for 21 days before packed into a soil column and subjected to leaching. Seven leaching events were conducted at days 1, 3, 7, 14, 28, 56, and 70, respectively, and 258.9 mL of deionized water was applied at each leaching events. The leachate was collected for the analyses of pH, electrical conductivity (EC), dissolved organic carbon (DOC), major elements, and heavy metals. DPR fertilizer application resulted in elevations up to 1 unit in pH, 7-10 times in EC, and 20-40 times in K and Ca concentrations, but 3-10 times reduction in P concentration in the leachate as compared with the chemical fertilizer or the control. After seven leaching events, DPR fertilizers with adequate DPR materials significantly reduced cumulative leaching losses of Fe, P, Mn, Cu, and Zn by 20, 55, 3.7, 2.7, and 2.5 times than chemical fertilizer or control. Even though higher cumulative losses of Pb, Co, and Ni were observed after DPR fertilizer application, the loss of Pb, Co, and Ni in leachate was <0.10 mg (in total 1,812 mL leachate). Significant correlations of pH (negative) and DOC (positive) with Cu, Pb, and Zn (P<0.01) in leachate were observed. The results indicated that DPR fertilizers had a great advantage over the soluble chemical fertilizer in reducing P loss from the acidic sandy soil with minimal likelihood of heavy metal risk to the water environment. pH elevation and high

  6. Soil amendments for heavy metals removal from stormwater runoff discharging to environmentally sensitive areas

    Science.gov (United States)

    Trenouth, William R.; Gharabaghi, Bahram

    2015-10-01

    Concentrations of dissolved metals in stormwater runoff from urbanized watersheds are much higher than established guidelines for the protection of aquatic life. Five potential soil amendment materials derived from affordable, abundant sources have been tested as filter media using shaker tests and were found to remove dissolved metals in stormwater runoff. Blast furnace (BF) slag and basic oxygenated furnace (BOF) slag from a steel mill, a drinking water treatment residual (DWTR) from a surface water treatment plant, goethite-rich overburden (IRON) from a coal mine, and woodchips (WC) were tested. The IRON and BOF amendments were shown to remove 46-98% of dissolved metals (Cr, Co, Cu, Pb, Ni, Zn) in repacked soil columns. Freundlich adsorption isotherm constants for six metals across five materials were calculated. Breakthrough curves of dissolved metals and total metal accumulation within the filter media were measured in column tests using synthetic runoff. A reduction in system performance over time occurred due to progressive saturation of the treatment media. Despite this, the top 7 cm of each filter media removed up to 72% of the dissolved metals. A calibrated HYDRUS-1D model was used to simulate long-term metal accumulation in the filter media, and model results suggest that for these metals a BOF filter media thickness as low as 15 cm can be used to improve stormwater quality to meet standards for up to twenty years. The treatment media evaluated in this research can be used to improve urban stormwater runoff discharging to environmentally sensitive areas (ESAs).

  7. Impact of sludge stabilization processes and sludge origin (urban or hospital) on the mobility of pharmaceutical compounds following sludge landspreading in laboratory soil-column experiments.

    Science.gov (United States)

    Lachassagne, Delphine; Soubrand, Marilyne; Casellas, Magali; Gonzalez-Ospina, Adriana; Dagot, Christophe

    2015-11-01

    This study aimed to determine the effect of sludge stabilization treatments (liming and anaerobic digestion) on the mobility of different pharmaceutical compounds in soil amended by landspreading of treated sludge from different sources (urban and hospital). The sorption and desorption potential of the following pharmaceutical compounds: carbamazepine (CBZ), ciprofloxacin (CIP), sulfamethoxazole (SMX), salicylic acid (SAL), ibuprofen (IBU), paracetamol (PAR), diclofenac (DIC), ketoprofen (KTP), econazole (ECZ), atenolol (ATN), and their solid-liquid distribution during sludge treatment (from thickening to stabilization) were investigated in the course of batch testing. The different sludge samples were then landspread at laboratory scale and leached with an artificial rain simulating 1 year of precipitation adapted to the surface area of the soil column used. The quality of the resulting leachate was investigated. Results showed that ibuprofen had the highest desorption potential for limed and digested urban and hospital sludge. Ibuprofen, salicylic acid, diclofenac, and paracetamol were the only compounds found in amended soil leachates. Moreover, the leaching potential of these compounds and therefore the risk of groundwater contamination depend mainly on the origin of the sludge because ibuprofen and diclofenac were present in the leachates of soils amended with urban sludge, whereas paracetamol and salicylic acid were found only in the leachates of soils amended with hospital sludge. Although carbamazepine, ciprofloxacin, sulfamethoxazole, ketoprofen, econazole, and atenolol were detected in some sludge, they were not present in any leachate. This reflects either an accumulation and/or (bio)degradation of these compounds (CBZ, CIP, SMX, KTP, ECZ, and ATN ), thus resulting in very low mobility in soil. Ecotoxicological risk assessment, evaluated by calculating the risk quotients for each studied pharmaceutical compound, revealed no high risk due to the

  8. Repacking practice for G-3 engineering driller power unit with drive shaft of dual channel reverse circulation

    Institute of Scientific and Technical Information of China (English)

    Lihong ZHU; Kun YIN; Qingyan WANG; Yong HUANG

    2008-01-01

    In order to satisfy operating requirements for constant core drilling technology in reverse circulation with hollow-through DTH,the power unit of G-3 engineering driller was ameliorated. The new one with dual channel drive shaft, achieved the perfect assemble with transmission structure of the original power unit. It could interconvert according to need by using two sets of drive shafts with direct and reverse circulation. The repacked G-3 engineering driller carried on experiment in the field test in Luanchuan molybdenum mine of Henan, whose effect was very good.

  9. Short-column anion-exchange chromatography for soil and peat humic substances profiling by step-wise gradient of high pH aqueous sodium ethylenediaminetetraacetate.

    Science.gov (United States)

    Hutta, Milan; Ráczová, Janka; Góra, Róbert; Pessl, Juraj

    2015-08-21

    Novel anion-exchange liquid chromatographic method with step gradient of aqueous EDTA(4-) based mobile phase elution has been developed to profile available Slovak soil humic substances and alkaline extracts of various soils. The method utilize short glass column (30mm×3mm) filled in with hydrolytically stable particles (60μm diameter) Separon HEMA-BIO 1000 having (diethylamino)ethyl functional groups. Step gradient was programmed by mixing mobile phase composed of aqueous solution of sodium EDTA (pH 12.0; 5mmolL(-1)) and mobile phase constituted of aqueous solution of sodium EDTA (pH 12.0, 500mmolL(-1)). The FLD of HSs was set to excitation wavelength 480nm and emission wavelength 530nm (λem). Separation mechanism was studied by use of selected aromatic acids related to humic acids with the aid of UV spectrophotometric detection at 280nm. The proposed method benefits from high ionic strength (I=5molL(-1)) of the end mobile phase buffer and provides high recovery of humic acids (98%). Accurate and reproducible profiling of studied humic substances, alkaline extracts of various types of soils enables straightforward characterization and differentiation of HSs in arable and forest soils. Selected model aromatic acids were used for separation mechanism elucidation.

  10. Mobility of coated and uncoated TiO2 nanomaterials in soil columns--Applicability of the tests methods of OECD TG 312 and 106 for nanomaterials.

    Science.gov (United States)

    Nickel, Carmen; Gabsch, Stephan; Hellack, Bryan; Nogowski, Andre; Babick, Frank; Stintz, Michael; Kuhlbusch, Thomas A J

    2015-07-01

    Nanomaterials are commonly used in everyday life products and during their life cycle they can be released into the environment. Soils and sediments are estimated as significant sinks for those nanomaterials. To investigate and assess the behaviour of nanomaterials in soils and sediments standardized test methods are needed. In this study the applicability of two existing international standardized test guidelines for the testing of nanomaterials, OECD TG 106 "Adsorption/Desorption using a Bath Equilibrium Method" and the OECD TG 312 "Leaching in Soil Columns", were investigated. For the study one coated and two uncoated TiO2 nanomaterials were used, respectively. The results indicate that the OECD TG 106 is not applicable for nanomaterials. However, the test method according to OECD TG 312 was found to be applicable if nano-specific adaptations are applied. The mobility investigations of the OECD TG 312 indicated a material-dependent mobility of the nanomaterials, which in some cases may lead to an accumulation in the upper soil layers. Whereas no significant transport was observed for the uncoated materials for the double-coated material (coating with dimethicone and aluminiumoxide) a significant transport was detected and attributed to the coating.

  11. Column experiments for elucidating heavy metal dynamics in an acidic forest soil fertilized with compost; Saeulenversuche zur Aufklaerung der Schwermetalldynamik auf einem mit Kompost geduengten sauren Waldboden

    Energy Technology Data Exchange (ETDEWEB)

    Aussendorf, M.

    1994-12-31

    The work studied the factors influencing heavy metal dynamics following compost fertilization of an acidic forest soil. In column experiments, profiles of podsolic soil from a Forchheim spruce site arranged as horizontal layers were exposed to overhead irrigation with watery compost extracts in a saturated stream of water. The compost extracts were varied at three levels as to the content of dissolved organic substance (DOC) and pH. Furthermore, columns with solutions of high and low ion strength were irrigated overhead without variation of DOC and pH. All irrigation solutions were adjusted to uniform heavy metal contents.- The column percolates were analysed regarding important cations and anions, pH and concentrations of DOC, Cu, Pb, Ni, Zn, and Cd. The results demonstrated that the high salt content of the irrigation solutions is responsible for heavy metal mobilization. (orig./MG) [Deutsch] In der vorliegenden Arbeit wurden die Einflussfaktoren der Schwermetalldynamik nach der Kompostduengung eines sauren Waldbodens untersucht. Hierzu wurden in Saeulenversuchen horizontierte Profile eines podsolierten Forchheimer Kiefernstandortes mit waessrigen Kompostextrakten im gesaettigten Wasserfluss beregnet. Die Kompostextrakte wurden auf 3 Niveaus bzgl. Gehalt an geloester organischer Substanz (DOC) und pH variiert. Weiterhin wurden Saeulen mit Loesungen hoher und niedriger Ionenstaerke ohne Variation des DOC-Gehaltes und des pH beregnet. Alle Beregnungsloesungen wurden auf einheitliche Schwermetallgehalte eingestellt. Die Saeulenperkolate wurden hinsichtlich wichtiger Kat- und Anionen, des pH und der Konzentrationen an DOC, Cu, Pb, Ni, Zn, und Cd analysiert. Die Ergebnisse zeigen, dass der hohe Salzgehalt der Beregnungsloesungen den entscheidenden Faktor fuer den Schwermetall-Austrag darstellt. (orig./MG)

  12. Removal and co-transport of Zn, As(V), and Cd during leachate seepage through downgradient mine soils: A batch sorption and column study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Juhee [Division of Environmental Science and Ecological Engineering, Korea University, Seoul (Korea, Republic of); Nam, Seung Mo [Korea Testing and Research Institute, Gyeonggi-do (Korea, Republic of); Hyun, Seunghun, E-mail: soilhyun@korea.ac.kr [Division of Environmental Science and Ecological Engineering, Korea University, Seoul (Korea, Republic of)

    2016-05-01

    The removal of Zn, As(V), and Cd during the leachate seepage process was measured in single, binary, and ternary solute systems by batch sorption and 1-D column flow experiments, followed by a sequential extraction procedure (SEP). In single-solute systems, sorption (K{sub d}{sup ⁎}) occurred in the order of As(V) > Zn ≫ Cd, and this sequence did not change in the presence of other solutes. In multi-solute systems, the sorption of Zn (~ 20%) and Cd (~ 27%) was enhanced by As(V), while Zn and Cd suppressed the sorption of each other. In all cases, As(V) sorption was not affected by the cations, indicating that As(V) is prioritized by sorption sites to a much greater degree than Zn and Cd. Element retention by column soils was strongly correlated (r{sup 2} = 0.77) with K{sub d}{sup ⁎}. Across column segments, mass retention was in the order of inlet (36–54%) > middle (26–35%) > outlet (20–31%), except for Cd in the Zn–Cd binary system. The result of SEP revealed that most of the retained Cd (98–99%) and Zn (56–71%) was in the labile fraction (e.g., the sum of F1 and F2) while only 9–12% of As(V) was labile and most (> 55%) was specifically adsorbed to Fe/Al oxides. Plots of the labile fraction (f{sub labile}) and the fast sorption fraction (f{sub fast}) suggested that the kinetics of specific As(V) sorption occur rapidly (f{sub fast} > f{sub labile}), whereas labile Zn and Cd sorption occurs slowly (f{sub labile} > f{sub fast}), indicating the occurrence of kinetically limited labile sorption sites, probably due to Zn–Cd competition. In conclusion, the element leaching potential of mine leachate can be greatly attenuated during downgradient soil seepage. However, when assessing the soil attenuation process, the impact of sorption competitors and the lability of adsorbed elements should first be considered. - Highlights: • During soil seepage, element leaching potential is reduced as As(V) > Zn > Cd. • Element removal during leachate seepage

  13. Distribution of Exchangeable Calcium,Magnesium and Potassium as Affected by Fertilizer Application to Red Soil

    Institute of Scientific and Technical Information of China (English)

    SHENREN-FANG; ZHAOQI-GUO

    1995-01-01

    A leaching experiment was Carried out with repacked soil columns in laboratory to study the leaching process of a red soil derived from sandstone as affected by various fertilization practices.The treatments were CK(as a control),CaCO3,CaSO4,MgCO3,Ca(H2PO4)2,Urea,KCl,Multiple(a mixture of the above mentioned fertilizers) and KNO3,The fertilizers were added to the bare surface of the soil columns,and then the columns were leached with 120 mL deionized water daily through perstaltic pumps over a period of 92 days,At the end of leaching process,soils were sampled from different depths of the soil profiles ,i.o.,of 92 days,At the end of leaching process,soils were sampled from different depths of the soil profiles,I.e.0-5cm,5-10cm,10-20cm,20-40cm,and 40-60cm,The results showed when applying Ca,Mg,and K to the bare surface of the soil columns,exchangeable Ca2+,Mg2+,and K+ in the upper layer of the soil profile increased correspondingly,with an extent depending mainly on the application rates of Ca,Mg,and K and showing a downward trend,CaCO3,CaSO4,MgCO3,and Ca(H2PO4)2 treatments had scarcely and effect on movement of exchangeable K+,while CaCO3,and CaSO4 treatments singnificantly promoted the downward movement of exchangealble Mg2+ although these two treatments had no obvious effect on leaching losses of Mg,The fact that under Urea treatment,exchangeable Ca2+ and Mg2+,were higher as compared to CK treatment showed urea could prevent leaching of exchangeable Ca2+and Mg2+,the obvious downward movement of exchangeable Ca2+and Mg2+ was noticed in KCl treatment ,In Multiple treatment,the downward movement of exchangeable Ca2+ and Mg2+ was evident,while that of K+ was less evident,Application of KNO3 strongly promoted the downward movement of exchangeable Ca2+and Mg2+ in the soil profile.

  14. Column flotation

    Energy Technology Data Exchange (ETDEWEB)

    Kohmuench, J.N.; Norrgran, D.A.; Luttrell, E.; Luttrell, G.H. [Virginia Tech. (United States)

    2008-04-15

    Over the last decade, column flotation has been recognised in the industry to be most efficient and economical means of recovering fine coal while maximizing product grade. When designed properly, flotation columns provide a high combustible recovery while maintaining a low product ash. The paper looks at the benefits of using column flotation for fine coal recovery. 2 refs., 5 figs.

  15. Developing risk models of Cryptosporidium transport in soils from vegetated, tilted soilbox experiments.

    Science.gov (United States)

    Harter, Thomas; Atwill, Edward R; Hou, Lingling; Karle, Betsy M; Tate, Kenneth W

    2008-01-01

    Transport of Cryptosporidium parvum through macroporous soils is poorly understood yet critical for assessing the risk of groundwater contamination. We developed a conceptual model of the physics of flow and transport in packed, tilted, and vegetated soilboxes during and immediately after a simulated rainfall event and applied it to 54 experiments implemented with different soils, slopes, and rainfall rates. Using a parsimonious inverse modeling procedure, we show that a significant amount of subsurface outflow from the soilboxes is due to macropore flow. The effective hydraulic properties of the macropore space were obtained by calibration of a simple two-domain flow and transport model that accounts for coupled flow in the matrix and in the macropores of the soils. Using linear mixed-effects analysis, macropore hydraulic properties and oocyst attenuation were shown to be associated with soil bulk density and rainfall rate. Macropore flow was shown to be responsible for bromide and C. parvum transport through the soil into the underlying pore space observed during the 4-h experiments. We confirmed this finding by conducting a pair of saturated soil column studies under homogeneously repacked conditions with no macropores in which no C. parvum transport was observed in the effluent. The linear mixed-effects and logistic regression models developed from the soilbox experiments provide a basis for estimating macropore hydraulic properties and the risk of C. parvum transport through shallow soils from bulk density, precipitation, and total shallow subsurface flow rate. The risk assessment is consistent with the reported occurrence of oocysts in springs or groundwater from fractured or karstic rocks protected only by shallow overlying soils.

  16. 洛克沙胂在土壤柱中的淋溶迁移%Leaching of Roxarsone in Soil Columns

    Institute of Scientific and Technical Information of China (English)

    张雨梅; 陈军; 史玉静; 刘慧岚

    2009-01-01

    The transport behavior of veterinarial drugs residue in animal manure into soils is essential for evaluating the potential ability leaching to groundwater. Roxarsone, a animal feed additive widely used for growth stimulation, run into soil with the fertilizer of animal manure. The transport characteristic of roxarsone in soil was investigated by leaching experiment in soil columns. The transport proportion of roxarsone to various depth Grayfluvo-aquicsoils leached by water, 0.01 mol·L~(-1) CaCl_2, 0.01 mol·L~(-1) EDTA-Na_2 were determined using soil column experiment. Effect of water-extract of chicken manure on leaching of roxarsone in different depth soils was also studied. Results showed all measured breakthrough curves (BTCs) of roxarsone exhibited extent of asymmetry with sharp adsorption and slow desorption fronts leaching by water, 0.01 mol·L~(-1) CaCl_2、0.01 mol·L~(-1) EDTA-Na_2. Comparing the dose of roxarsone to soil column, the leaching rate in different depth soils was 92.3%~97.1% by water, 71.0%~84.9% by 0.01 mol·L~(-1) CaCl_2, 75.4%~91.2% by 0.01 mol·L~(-1) EDTA-Na_2 respectively. When the water-extract of chicken manure was firstly through these soil columns, the peak time of BTCs was all shortened and the content of roxarsone leached from soil was all increased, with leaching rate 96.4%~110.4% by water, 94.5%~106.8% by 0.01 mol·L~(-1) CaCl_2, 90.8%~103.2% by 0.01 mol·L~(-1) EDTA-Na_2. It was came to a conclusion that roxarsone into soil with the manure application could be fastly leached into groundwater from different depth soils, being a risk to water environment.%畜禽粪便中残留的兽药进入土壤后的移动性是评价其淋溶能力(对地下水的污染风险)的重要信息.通过土壤柱稳定流实验,考察了不同淋溶剂、粪浸液等对洛克沙胂在不同深度(0~20、20~50、50~80 cm)灰潮土中的迁移行为影响.结果表明,水、0.01mol·L~(-1) CaCl_2、0.01 mol·L~(-1) EDTA-Na2淋溶

  17. Influence of soil properties on vapor-phase sorption of trichloroethylene

    Energy Technology Data Exchange (ETDEWEB)

    Bekele, Dawit N. [Global Center for Environmental Remediation, University of Newcastle, Callaghan, NSW 2308 (Australia); CRC for Contamination Assessment & Remediation of the Environment, Building X (Environmental Sciences Building), University of South Australia, Mawson Lakes, SA 5095 (Australia); Naidu, Ravi, E-mail: Ravi.Naidu@newcastle.edu.au [Global Center for Environmental Remediation, University of Newcastle, Callaghan, NSW 2308 (Australia); CRC for Contamination Assessment & Remediation of the Environment, Building X (Environmental Sciences Building), University of South Australia, Mawson Lakes, SA 5095 (Australia); Chadalavada, Sreenivasulu [Global Center for Environmental Remediation, University of Newcastle, Callaghan, NSW 2308 (Australia); CRC for Contamination Assessment & Remediation of the Environment, Building X (Environmental Sciences Building), University of South Australia, Mawson Lakes, SA 5095 (Australia)

    2016-04-05

    Highlights: • Vapor intrusion is a major exposure pathway for volatile hydrocarbons. • Certainty in transport processes enhances vapor intrusion model precision. • Detailed understanding of vadose zone vapor transport processes save resources. • Vapor sorption near-steady-state conditions at sites may take months or years. • Type of clay fractions equitably affects sorption of trichloroethylene vapor. - Abstract: Current practices in health risk assessment from vapor intrusion (VI) using mathematical models are based on assumptions that the subsurface sorption equilibrium is attained. The time required for sorption to reach near-steady-state conditions at sites may take months or years to achieve. This study investigated the vapor phase attenuation of trichloroethylene (TCE) in five soils varying widely in clay and organic matter content using repacked columns. The primary indicators of TCE sorption were vapor retardation rate (R{sub t}), the time required for the TCE vapor to pass through the soil column, and specific volume of retention (V{sub R}), and total volume of TCE retained in soil. Results show TCE vapor retardation is mainly due to the rapid partitioning of the compound to SOM. However, the specific volume of retention of clayey soils with secondary mineral particles was higher. Linear regression analyses of the SOM and clay fraction with V{sub R} show that a unit increase in clay fraction results in higher sorption of TCE (V{sub R}) than the SOM. However, partitioning of TCE vapor was not consistent with the samples' surface areas but was mainly a function of the type of secondary minerals present in soils.

  18. Removal and co-transport of Zn, As(V), and Cd during leachate seepage through downgradient mine soils: A batch sorption and column study.

    Science.gov (United States)

    Kim, Juhee; Nam, Seung Mo; Hyun, Seunghun

    2016-05-01

    The removal of Zn, As(V), and Cd during the leachate seepage process was measured in single, binary, and ternary solute systems by batch sorption and 1-D column flow experiments, followed by a sequential extraction procedure (SEP). In single-solute systems, sorption (Kd(⁎)) occurred in the order of As(V)>Zn≫Cd, and this sequence did not change in the presence of other solutes. In multi-solute systems, the sorption of Zn (~20%) and Cd (~27%) was enhanced by As(V), while Zn and Cd suppressed the sorption of each other. In all cases, As(V) sorption was not affected by the cations, indicating that As(V) is prioritized by sorption sites to a much greater degree than Zn and Cd. Element retention by column soils was strongly correlated (r(2)=0.77) with Kd(⁎). Across column segments, mass retention was in the order of inlet (36-54%)>middle (26-35%)>outlet (20-31%), except for Cd in the Zn-Cd binary system. The result of SEP revealed that most of the retained Cd (98-99%) and Zn (56-71%) was in the labile fraction (e.g., the sum of F1 and F2) while only 9-12% of As(V) was labile and most (>55%) was specifically adsorbed to Fe/Al oxides. Plots of the labile fraction (f(labile)) and the fast sorption fraction (f(fast)) suggested that the kinetics of specific As(V) sorption occur rapidly (f(fast)>f(labile)), whereas labile Zn and Cd sorption occurs slowly (f(labile)>f(fast)), indicating the occurrence of kinetically limited labile sorption sites, probably due to Zn-Cd competition. In conclusion, the element leaching potential of mine leachate can be greatly attenuated during downgradient soil seepage. However, when assessing the soil attenuation process, the impact of sorption competitors and the lability of adsorbed elements should first be considered.

  19. Effect of vegetation on the longevity, mobility and activity of fipronil applied at the termiticidal rate in laboratory soil columns

    Science.gov (United States)

    Christopher Peterson

    2010-01-01

    BACKGROUND: Termiticides are applied at concentrations much higher than those used in agricultural settings. The longevity of fipronil has not yet been examined at the rates used for termite control, nor has the compound’s movement in the soil been addressed.

  20. Utilization and leaching of nitrate from two Deschampsia- dominated heathland sites: a lysimeter study using intact soil columns

    NARCIS (Netherlands)

    Troelstra, S.R.; Wagenaar, R.; Smant, W.

    1997-01-01

    High deposition levels of atmospheric ammonia in the Netherlands have led to the major replacement of dwarf shrubs by grasses and to elevated nitrification rates in acid heathland soils. In order to study the efficacy of a naturally established grass-heath of Deschampsia flexuosa at capturing NO3-,

  1. Utilization and leaching of nitrate from two Deschampsia- dominated heathland sites: a lysimeter study using intact soil columns

    NARCIS (Netherlands)

    Troelstra, S.R.; Wagenaar, R.; Smant, W.

    1997-01-01

    High deposition levels of atmospheric ammonia in the Netherlands have led to the major replacement of dwarf shrubs by grasses and to elevated nitrification rates in acid heathland soils. In order to study the efficacy of a naturally established grass-heath of Deschampsia flexuosa at capturing NO3-,

  2. CONSTRUCTION OF A NEW HIGHWAY EMBANKMENT ON THE SOFT CLAY SOIL TREATMENT BY STONE COLUMNS IN MALAYSIA

    Directory of Open Access Journals (Sweden)

    QASIM A. ALJANABI

    2013-08-01

    Full Text Available To continue of the second phase of the East Coast Expressway between Kuantan and Kula Terengganu in Malaysia system innovative solution are required. In this new phase there are embankment region has been subjected to extensive soft clay soil. These comprise typically of clayey silts of very high water content and undrained shear strengths in the range of 8 to 11 kPa to depths of up to 8m. To support an embankment height of up to 12 m, were filled and thereafter Vibro Replacement treatment was carried out to treat the very soft soil. Extensive instrumentation using rod settlement gauges, inclinometers and piezometers were installed to monitor the performance of the Vibro Replacement treatment. This paper reports on aspects of design, installation and the measured results from the instrumentation scheme.

  3. Modelling Pesticide Leaching At Column, Field and Catchment Scales I. Analysis of Soil Variability At Field and Catchment Scales

    Science.gov (United States)

    Gärdenäs, A.; Jarvis, N.; Alavi, G.

    The spatial variability of soil characteristics was studied in a small agricultural catch- ment (Vemmenhög, 9 km2) at the field and catchment scales. This analysis serves as a basis for assumptions concerning upscaling approaches used to model pesticide leaching from the catchment with the MACRO model (Jarvis et al., this meeting). The work focused on the spatial variability of two key soil properties for pesticide fate in soil, organic carbon and clay content. The Vemmenhög catchment (9 km2) is formed in a glacial till deposit in southernmost Sweden. The landscape is undulating (30 - 65 m a.s.l.) and 95 % of the area is used for crop production (winter rape, winter wheat, sugar beet and spring barley). The climate is warm temperate. Soil samples for or- ganic C and texture were taken on a small regular grid at Näsby Farm, (144 m x 144 m, sampling distance: 6-24 m, 77 points) and on an irregular large grid covering the whole catchment (sampling distance: 333 m, 46 points). At the field scale, it could be shown that the organic C content was strongly related to landscape position and height (R2= 73 %, p organic C content of hollows in the landscape is so high that they contribute little to the total loss of pesticides (Jarvis et al., this meeting). Clay content is also related to landscape position, being larger at the hilltop locations resulting in lower near-saturated hydraulic conductivity. Hence, macropore flow can be expected to be more pronounced (see also Roulier & Jarvis, this meeting). The variability in organic C was similar for the field and catchment grids, which made it possible to krige the organic C content of the whole catchment using data from both grids and an uneven lag distance.

  4. Antimony speciation in soils: improving the detection limits using post-column pre-reduction hydride generation atomic fluorescence spectroscopy (HPLC/pre-reduction/HG-AFS).

    Science.gov (United States)

    Quiroz, Waldo; Olivares, David; Bravo, Manuel; Feldmann, Jorg; Raab, Andrea

    2011-04-15

    HG-AFS is highly sensitive and low cost detection system and its use for antimony chemical speciation coupled to HPLC is gaining popularity. However speciation analysis in soils is strongly hampered because the most efficient extractant reported in the literature (oxalic acid) strongly inhibits the generation of SbH(3) by Sb(V), the major species in this kind of matrix, severely affecting its detection limits. The purpose of this research is to reduce the detection limit of Sb(V), by using a post column on-line reduction system with l-cysteine reagent (HPLC/pre-reduction/HG-AFS). The system was optimized by experimental design, optimum conditions found were 2% (w/v) and 10°C temperature coil. Detection limits of Sb(V) and Sb(III) in oxalic acid (0.25 mol L(-1)) were improved from 0.3 and 0.1 μg L(-1) to 0.07 and 0.07 μg L(-1), respectively. The methodology developed was applied to Chilean soils, where Sb(V) was the predominant species. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Reading Columns

    OpenAIRE

    Coutts, Marion

    2008-01-01

    Reading Columns are twin permanent public sculptures commissioned as part of a £245m scheme for the redevelopment of the Chatham Place area in Reading. Dimensions: 3.5m high x 1.3m diameter each Field of knowledge: The work consists of twin bespoke columns of stainless steel and glass over digital colour transparencies. The piece revisits and reworks the idea of the Morris Column, a 19th C feature characteristic of major European metropolitan centres. A wraparound image on each of ...

  6. Leaching of Nutrient Elements in a Red Soil Derived from Quaternary Red Clay

    Institute of Scientific and Technical Information of China (English)

    SHENRENFANG; ZHAOQIGUO

    1998-01-01

    A red soil derived from Quaternary red clay was employed to study nutrient leaching with woil columns repacked in laboratory,The objective was to identify the effects of fertilization practices on leaching patterns and magnitudes of Ca2+,Mg2+,K+,NH4+,and NO3-,The treatments were CK (as a control),CaCO3, CaSO4,MgCO3,Ca(H2PO4)2,urea,KCl,and multiple (a mixture of the above-mentioned fertilizers),The fertilizers were added to the bare surface of the soil columns,and then the columns were leached with 120 mL deionized water daily through peristaltic pumps over a period of 92 days.Leaching processes of NH4+,and NO3- wer e only measured in CK,ured,and multiple treatments which were directly related to N leaching, Results showed that sole application of CaSO4,and Ca(H2PO4)2 scarcely hd any effect on the leching losses of Ca2+,Mg2+,and K+; the application of MgCO3 sthimulated the leaching of Mg2+;the application of CaCO3 promoted the leaching of Ca2+,Mg2+ and K+; urea treatment also promoted the leaching of K+ and NH4+,and NO3- leaching mainly occurred at late stage of leaching process in particular;under KCl treatment,leaching of Ca2+,Mg2+,and K+ was promoted to a large extent;under multiple treatment, leaching of Ca2+,Mg2+,K+,NH4+,and NO3- was all increased and NO3- was mainly leached at the end of leaching process and still had a trend of increase.

  7. 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)

  8. Column: lef

    NARCIS (Netherlands)

    Reep, Frans van der

    2012-01-01

    1e alinea column: Ook in je beleggingsbeslissingen is het voor echte performance wellicht tijd om eens voorbij best practices (dan word je namelijk hoogstens tweede) te kijken naar next practices. Als je op zeker speelt, verdien je weinig geld. Want anderen gingen je al voor. Maar kun je nog meer op

  9. Study on Pile-soil Stress Ratio of Composite Foundation Reinforced with Geosynthetic Encased Stone Columns%筋箍碎石桩复合地基桩土应力比的计算与分析∗

    Institute of Scientific and Technical Information of China (English)

    张玲; 陈哲; 赵明华

    2017-01-01

    针对筋箍碎石桩复合地基的受力变形特点,考虑桩土的初始应力状态,假定桩为具有恒定剪胀角的弹塑性体,且满足摩尔库伦屈服准则与非关联流动法则,土体和加筋体为线弹性材料,考虑桩筋材土三者间相互作用,导得了筋箍碎石桩复合地基桩土应力比计算新公式。为验证本文计算公式的可行性,将本文方法计算结果与弹塑性极限分析方法结果进行对比分析,两者吻合良好。在此基础上,分析探讨了筋材刚度、桩周土变形模量、面积置换率等因素对筋箍碎石桩复合地基桩土应力比的影响。分析结果表明:筋材刚度是桩土应力比的主要影响因素,桩土应力比随筋材刚度、面积置换率、桩体内摩擦角的增大而增大,随着桩周土变形模量和桩体剪胀角的增大而减小。%Based on the deformation characteristics of the composite foundation reinforced with encased stone columns under vertical loads,a new calculation formula to estimate the pile-soil stress ratio of geo-synthetic-encased stone columns was proposed with consideration of pile-geosynthetic-soil interactions.In the derivation process,initial stresses in soil and a column were taken into account,the column was con-sidered as an elastic-plastic material with constant dilatancy angle and satisfying both the Mohr-Coulomb yield criterion and non-associated flow rule,and the soil and geosynthetic encasement were considered as linear-elastic materials.The proposed formula was validated by comparison with the results of elasto-plas-tic limit analysis method.Finally,a parametric study was conducted to investigate various parameter effects of encasement stiffness,deformation modulus of soil,and replacement ratio on the behavior of the pile-soil stress ratio.The parametric study shows that the pile-soil stress ratio of the composite foundation with the encased stone column increases with the increase of encasement

  10. Determination of Wastewater Compounds in Sediment and Soil by Pressurized Solvent Extraction, Solid-Phase Extraction, and Capillary-Column Gas Chromatography/Mass Spectrometry

    Science.gov (United States)

    Burkhardt, Mark R.; Zaugg, Steven D.; Smith, Steven G.; ReVello, Rhiannon C.

    2006-01-01

    A method for the determination of 61 compounds in environmental sediment and soil samples is described. The method was developed in response to increasing concern over the effects of endocrine-disrupting chemicals in wastewater and wastewater-impacted sediment on aquatic organisms. This method also may be used to evaluate the effects of combined sanitary and storm-sewer overflow on the water and sediment quality of urban streams. Method development focused on the determination of compounds that were chosen on the basis of their endocrine-disrupting potential or toxicity. These compounds include the alkylphenol ethoxylate nonionic surfactants and their degradates, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic aromatic hydrocarbons, and high-use domestic pesticides. Sediment and soil samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted from interfering matrix components by high-pressure water/isopropyl alcohol extraction. The compounds were isolated using disposable solid-phase extraction (SPE) cartridges containing chemically modified polystyrene-divinylbenzene resin. The cartridges were dried with nitrogen gas, and then sorbed compounds were eluted with methylene chloride (80 percent)-diethyl ether (20 percent) through Florisil/sodium sulfate SPE cartridge, and then determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-sand samples fortified at 4 to 72 micrograms averaged 76 percent ?13 percent relative standard deviation for all method compounds. Initial method reporting levels for single-component compounds ranged from 50 to 500 micrograms per kilogram. The concentrations of 20 out of 61 compounds initially will be reported as estimated with the 'E' remark code for one of three reasons: (1) unacceptably low-biased recovery (less than 60 percent) or highly variable method performance

  11. Tropospheric vertical column densities of NO2 over managed dryland ecosystems (Xinjiang, China): MAX-DOAS measurements vs. 3-D dispersion model simulations based on laboratory-derived NO emission from soil samples

    Science.gov (United States)

    Mamtimin, B.; Behrendt, T.; Badawy, M. M.; Wagner, T.; Qi, Y.; Wu, Z.; Meixner, F. X.

    2015-01-01

    We report on MAX-DOAS observations of NO2 over an oasis-ecotone-desert ecosystem in NW China. There, local ambient NO2 concentrations originate from enhanced biogenic NO emission of intensively managed soils. Our target oasis "Milan" is located at the southern edge of the Taklimakan desert, very remote and well isolated from other potential anthropogenic and biogenic NOx sources. Four observation sites for MAX-DOAS measurements were selected, at the oasis centre, downwind and upwind of the oasis, and in the desert. Biogenic NO emissions in terms of (i) soil moisture and (ii) soil temperature of Milan oasis (iii) different land-cover type sub-units (cotton, Jujube trees, cotton/Jujube mixture, desert) were quantified by laboratory incubation of corresponding soil samples. Net potential NO fluxes were up-scaled to oasis scale by areal distribution and classification of land-cover types derived from satellite images using GIS techniques. A Lagrangian dispersion model (LASAT, Lagrangian Simulation of Aerosol Transport) was used to calculate the dispersion of soil emitted NO into the atmospheric boundary layer over Milan oasis. Three-dimensional (3-D) NO concentrations (30 m horizontal resolution) have been converted to 3-D NO2 concentrations, assuming photostationary state conditions. NO2 column densities were simulated by suitable vertical integration of modelled 3-D NO2 concentrations at those downwind and upwind locations, where the MAX-DOAS measurements were performed. Downwind-upwind differences (a direct measure of Milan oasis' contribution to the areal increase of ambient NO2 concentration) of measured and simulated slant (as well as vertical) NO2 column densities show excellent agreement. This agreement is considered as the first successful attempt to prove the validity of the chosen approach to up-scale laboratory-derived biogenic NO fluxes to ecosystem field conditions, i.e. from the spatial scale of a soil sample (cm2) to the size of an entire agricultural

  12. Tropospheric vertical column densities of NO2 over managed dryland ecosystems (Xinjiang, China): MAX-DOAS measurements vs. 3-D dispersion model simulations based on laboratory derived NO emission from soil samples

    Science.gov (United States)

    Mamtimin, B.; Behrendt, T.; Badawy, M. M.; Wagner, T.; Qi, Y.; Wu, Z.; Meixner, F. X.

    2014-07-01

    We report on MAX-DOAS observations of NO2 over an oasis-ecotone-desert ecosystem in NW-China. There, local ambient NO2 concentrations originate from enhanced biogenic NO emission of intensively managed soils. Our target oasis "Milan" is located at the southern edge of the Taklimakan desert, very remote and well isolated from other potential anthropogenic and biogenic NOx sources. Four observation sites for MAX-DOAS measurements were selected, at the oasis center, downwind and upwind of the oasis, and in the desert. Biogenic NO emissions in terms of (i) soil moisture and (ii) soil temperature of Milan oasis' (iii) different land-cover type sub-units (cotton, Jujube trees, cotton/Jujube mixture, desert) were quantified by laboratory incubation of corresponding soil samples. Net potential NO fluxes were up-scaled to oasis scale by areal distribution and classification of land-cover types derived from satellite images using GIS techniques. A Lagrangian dispersion model (LASAT, Lagrangian Simulation of Aerosol-Transport) was used to calculate the dispersion of soil emitted NO into the atmospheric boundary layer over Milan oasis. Three dimensional NO concentrations (30 m horizontal resolution) have been converted to 3-D NO2 concentrations, assuming photostationary state conditions. NO2 column densities were simulated by suitable vertical integration of modeled 3-D NO2 concentrations at those downwind and upwind locations, where the MAX-DOAS measurements were performed. Downwind-upwind differences (a direct measure of Milan oasis' contribution to the areal increase of ambient NO2 concentration) of measured and simulated slant (as well as vertical) NO2 column densities show excellent agreement. This agreement is considered as the first successful attempt to prove the validity of the chosen approach to up-scale laboratory derived biogenic NO fluxes to ecosystem field conditions, i.e. from the spatial scale of a soil sample (cm2) to the size of an entire agricultural

  13. Tropospheric vertical column densities of NO2 over managed dryland ecosystems (Xinjiang, China: MAX-DOAS measurements vs. 3-D dispersion model simulations based on laboratory derived NO emission from soil samples

    Directory of Open Access Journals (Sweden)

    B. Mamtimin

    2014-07-01

    Full Text Available We report on MAX-DOAS observations of NO2 over an oasis-ecotone-desert ecosystem in NW-China. There, local ambient NO2 concentrations originate from enhanced biogenic NO emission of intensively managed soils. Our target oasis "Milan" is located at the southern edge of the Taklimakan desert, very remote and well isolated from other potential anthropogenic and biogenic NOx sources. Four observation sites for MAX-DOAS measurements were selected, at the oasis center, downwind and upwind of the oasis, and in the desert. Biogenic NO emissions in terms of (i soil moisture and (ii soil temperature of Milan oasis' (iii different land-cover type sub-units (cotton, Jujube trees, cotton/Jujube mixture, desert were quantified by laboratory incubation of corresponding soil samples. Net potential NO fluxes were up-scaled to oasis scale by areal distribution and classification of land-cover types derived from satellite images using GIS techniques. A Lagrangian dispersion model (LASAT, Lagrangian Simulation of Aerosol-Transport was used to calculate the dispersion of soil emitted NO into the atmospheric boundary layer over Milan oasis. Three dimensional NO concentrations (30 m horizontal resolution have been converted to 3-D NO2 concentrations, assuming photostationary state conditions. NO2 column densities were simulated by suitable vertical integration of modeled 3-D NO2 concentrations at those downwind and upwind locations, where the MAX-DOAS measurements were performed. Downwind-upwind differences (a direct measure of Milan oasis' contribution to the areal increase of ambient NO2 concentration of measured and simulated slant (as well as vertical NO2 column densities show excellent agreement. This agreement is considered as the first successful attempt to prove the validity of the chosen approach to up-scale laboratory derived biogenic NO fluxes to ecosystem field conditions, i.e. from the spatial scale of a soil sample (cm2 to the size of an entire

  14. Removal of non aqueous phase liquid liquid (NAPL) from a loam soil monitored by time domain reflectometry (TDR) technique

    Science.gov (United States)

    comegna, alessandro; coppola, Antonio; dragonetti, giovanna; ajeel, ali; saeed, ali; sommella, angelo

    2016-04-01

    Non-aqueous phase liquids (NAPLs) are compounds with low or no solubility with water. These compounds, due to the several human activities, can be accidentally introduced in the soil system and thus constitute a serious geo-environmental problem, given the toxicity level and the high mobility. The remediation of contaminated soil sites requires knowledge of the contaminant distribution in the soil profile and groundwater. Methods commonly used to characterize contaminated sites are coring, soil sampling and the installation of monitoring wells for the collection of groundwater samples. The main objective of the present research is to explore the potential application of time domain reflectometry (TDR) technique in order to evaluate the effect of contaminant removal in a loam soil, initially contaminated with NAPL and then flushed with different washing solutions. The experimental setup consist of: i) a Techtronix cable tester; ii) a three-wire TDR probe with wave guides 14.5 cm long inserted vertically into the soil samples; iii) a testing cell of 8 cm in diameter and 15 cm high; iv) a peristaltic pump for upward injection of washing solution. In laboratory, soil samples were oven dried at 105°C and passed through a 2 mm sieve. Known quantities of soil and NAPL (corn oil, a non-volatile and non-toxic organic compound) were mixed in order to obtain soil samples with different degrees of contamination. Once a soil sample was prepared, it was repacked into a plastic cylinder and then placed into the testing cell. An upward injection of washing solution was supplied to the contaminated sample with a rate q=1.5 cm3/min, which corresponds to a darcian velocity v=6.0 cm/h. The out coming fluid, from the soil column was collected, then the washing solution and oil was separated. Finally both the amount of oil that was remediated and the dielectric permittivity (measured via TDR) of the contaminated soil sample were recorded. Data collected were employed to implement a

  15. Chemometrics applications in biotechnology processes: predicting column integrity and impurity clearance during reuse of chromatography resin.

    Science.gov (United States)

    Rathore, Anurag S; Mittal, Shachi; Lute, Scott; Brorson, Kurt

    2012-01-01

    Separation media, in particular chromatography media, is typically one of the major contributors to the cost of goods for production of a biotechnology therapeutic. To be cost-effective, it is industry practice that media be reused over several cycles before being discarded. The traditional approach for estimating the number of cycles a particular media can be reused for involves performing laboratory scale experiments that monitor column performance and carryover. This dataset is then used to predict the number of cycles the media can be used at manufacturing scale (concurrent validation). Although, well accepted and widely practiced, there are challenges associated with extrapolating the laboratory scale data to manufacturing scale due to differences that may exist across scales. Factors that may be different include: level of impurities in the feed material, lot to lot variability in feedstock impurities, design of the column housing unit with respect to cleanability, and homogeneity of the column packing. In view of these challenges, there is a need for approaches that may be able to predict column underperformance at the manufacturing scale over the product lifecycle. In case such an underperformance is predicted, the operators can unpack and repack the chromatography column beforehand and thus avoid batch loss. Chemometrics offers one such solution. In this article, we present an application of chemometrics toward the analysis of a set of chromatography profiles with the intention of predicting the various events of column underperformance including the backpressure buildup and inefficient deoxyribonucleic acid clearance.

  16. Soils

    Science.gov (United States)

    Emily Moghaddas; Ken Hubbert

    2014-01-01

    When managing for resilient forests, each soil’s inherent capacity to resist and recover from changes in soil function should be evaluated relative to the anticipated extent and duration of soil disturbance. Application of several key principles will help ensure healthy, resilient soils: (1) minimize physical disturbance using guidelines tailored to specific soil types...

  17. Prediction of the soil water retention curve for structured soil from saturation to oven-dryness

    DEFF Research Database (Denmark)

    Karup, Dan; Møldrup, Per; Tuller, Markus

    2017-01-01

    The soil water retention curve (SWRC) is the most fundamental soil hydraulic function required for modelling soil–plant–atmospheric water flow and transport processes. The SWRC is intimately linked to the distribution of the size of pores, the composition of the solid phase and the soil specific....... In this research we evaluated a new two-stage approach developed recently to predict the SWRC based onmeasurements for disturbed repacked soil samples. Our study involved undisturbed structured soil and took into account the effects of bulk density, organic matter content and particle-size distribution....... Independently measured SWRCs for 171 undisturbed soil samples with organic matter contents that ranged from 3 to 14% were used for model validation. The results indicate that consideration of the silt and organic matter fractions, in addition to the clay fraction, improved predictions for the dry-end SWRC...

  18. Influência da geometria e umidade de colunas de solo na biodegradação de filmes de PCL Influence of geometry and humidity of soil columns in the biodegradation of PCL films

    Directory of Open Access Journals (Sweden)

    Suely P. C. Gonçalves

    2011-01-01

    Full Text Available Filmes de poli(ε-caprolactona (PCL foram preparados por compressão a quente e investigados com respeito a sua biodegradação em diferentes colunas de solo, após 60 dias. A morfologia e estrutura dos filmes, após os diferentes tratamentos, foram verificadas através de medidas de perda de massa, espectroscopia no infravermelho com transformada de Fourier (FTIR, calorimetria exploratória diferencial (DSC, termogravimetria (TG e microscopia eletrônica de varredura (MEV. Os filmes de PCL sofreram biodegradação, principalmente na fase amorfa, atribuídas a quebras das ligações ésteres da cadeia polimérica, devido à ação de exo-enzimas dos microrganismos do solo. Os fatores abióticos, tais como temperatura, pH, quantidade de oxigênio e principalmente tipo de coluna de solo e umidade, foram aspectos considerados relevantes no processo de biodegradação dos filmes de PCL em solo.Poly (ε-caprolactone (PCL films were prepared by melt-pressing and investigated with respect to their biodegradation in different soil columns after 60 days. The morphology and structure of the films, after various microbial treatments, were studied with measurements of mass loss, Fourier transform infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, thermogravimetry ( TG and scanning electron microscopy (SEM. The PCL films underwent biodegradation, mainly in the amorphous phase, attributed to breaking of ester bonds of the polymer chain due to the action of exo-enzymes from soil microorganisms. The abiotic factors such as temperature, pH, oxygen content and principally soil column type and humidity were considered important aspects for the biodegradation process on the PCL films in soil.

  19. Avaliação do regime estacionário em colunas de amostras deformadas de solo sob saturação Evaluation of the stationary condition in disturbed saturated soil columns

    Directory of Open Access Journals (Sweden)

    Luciana de Pinho Cunha

    2007-10-01

    studies. Disturbed soil samples were collected in an experimental area of the ESALQ/USP. The soils had three different granulometries: very clayey, sandy-loam and sandy soil. PVC columns were filled with soil samples and then distilled and deaerated water was used for saturation and subsequent drainage in the columns, according to the experimental set-up of a constant-head permeameter. The data showed that for very clayey and sandy-loam samples, the steady-state was reached after 15 days and for the sandy soil after 27 days. The variability of K0 was higher in the first six test days. It was therefore concluded that the use of a fixed time for the addition of solutes in soil can result in a reduction of reliability in results.

  20. Automated Composite Column Wrapping

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    The Automated Composite Column Wrapping is performed by a patented machine known as Robo-Wrapper. Currently there are three versions of the machine available for bridge retrofit work depending on the size of the columns being wrapped. Composite column retrofit jacket systems can be structurally just as effective as conventional steel jacketing in improving the seismic response characteristics of substandard reinforced concrete columns.

  1. Modelo para simulação da dinâmica de nitrato em colunas verticais de solo não saturado A simulation model of nitrate displacement in vertical columns in a non-saturated soil

    Directory of Open Access Journals (Sweden)

    Jarbas H. de Miranda

    2002-01-01

    Full Text Available A agricultura intensiva está sempre em busca de incrementos de produtividade mas, em contrapartida, pouca atenção é dedicada a possíveis impactos ambientais. Portanto, o entendimento sobre processos de transporte de solutos no solo auxilia na redução da sua lixiviação para as camadas subsuperficiais. Neste sentido, objetivou-se, com o presente trabalho, desenvolver e avaliar um modelo computacional aplicado para simulação da dinâmica de solutos no solo por meio de soluções numéricas de equações diferenciais que descrevam esse transporte. Pelos resultados obtidos, o modelo apresentou bom ajuste das concentrações de nitrato e dos perfis de umidade, simulados com relação aos medidos em condições de laboratório em coluna vertical de solo não saturado.Intensive agriculture always aims at increased productivity, with limited or no attention dedicated to possible impacts on the environment. Therefore, the understanding of processes of solute transport in the soil contributes to reduction of leaching to the deep layers. In this connection, the present study had the objective of developing and evaluating a computational model for solute displacement simulation in the soil based on numerical solutions of differential equations describing this displacement. From the results obtained, the model presented a good agreement of nitrate concentrations as well as soil moisture profile when compared with the results obtained on a vertical column of non-saturated soil under laboratory conditions.

  2. Analysis on the Reinforcement of Soft Soil Subgrade by Using Vibro-replacement Stone Column in Expressway Construction%高速公路工程软土路基应用振冲碎石桩加固分析

    Institute of Scientific and Technical Information of China (English)

    邓强; 肖莹

    2015-01-01

    高速公路对路基沉降的要求很高,选择正确的地基处理方式直接关系到工程质量、投资和进度。本文对振冲碎石桩设计方法、施工工艺以及工程质量控制等进行了研究,并给出了振冲碎石桩在京珠高速公路软土路基加固中的应用实例。%Expressway has high requirements on the roadbed settlement, the right selection of foundation treatment way is directly related to the quality, investment and progress of the construction. This paper studies the design methods, construction technology and construction quality control of vibro-replacement stone column, and puts forward the application examples of vibro-replacement stone column of the soft soil subgrade reinforcement in Jingzhu Expressway.

  3. Dynamics of digging in wet soil

    CERN Document Server

    Jung, Sunghwan; Hosoi, A E

    2010-01-01

    Numerous animals live in, and locomote through, subsea soils. To move in a medium dominated by frictional interactions, many of these animals have adopted unique burrowing strategies. This paper presents a burrowing model inspired by the Atlantic razor clam ({\\it Ensis directus}), which uses deformations of its body to cyclically loosen and re-pack the surrounding soil in order to locally manipulate burrowing drag. The model reveals how an anisotropic body -- composed of a cylinder and sphere varying sinusoidally in size and relative displacement -- achieves unidirectional motion through a medium with variable frictional properties. This net displacement is attained even though the body kinematics are reciprocal and inertia of both the model organism and the surrounding medium are negligible. Our results indicate that body aspect ratio has a strong effect on burrowing velocity and efficiency, with a well-defined maximum for given kinematics and soil material properties.

  4. Efeito da adição de diferentes fontes de cálcio no movimento de cátions em colunas de solo Effect of several calcium sources on cation leaching using soil columns

    Directory of Open Access Journals (Sweden)

    I.C. de Maria

    1993-05-01

    Full Text Available No estudo realizado em colunas de solo montadas em laboratório, procurou-se avaliar o movimento do cálcio, e de outros cátions, após aplicação de calcário agrícola, gesso, calcário calcinado e uma mistura de calcário agrícola e gesso, comparados com um tratamento testemunha, em dois latossolos vermelho escuros de texturas diferentes: média e argilosa. Utilizaram-se colunas de PVC, com 5cm de diâmetro e 45cm de altura, e aplicaram-se em cada coluna 1,8 litros de água, parcelados em quatro vezes. Determinaram-se os cátions trocáveis presentes na água percolada e, no final do experimento, em cinco profundidades de cada solo. Os resultados mostraram que nos tratamentos gesso e calcário mais gesso as quantidades de Ca2+, Mg2+, K+ e Al3+ na solução percolada foram maiores, enquanto que os tratamentos calcário agrícola e calcário calcinado não promoveram perdas significativas de cátions. As maiores perdas ocorreram na primeira percolação no solo de textura média e na segunda no solo de textura argilosa. O gesso não modificou o pH dos solos, mas reduziu teores de bases no solo argiloso, enquanto que os calcários corrigiram o solo apenas próximo à camada de incorporação.Soil columns under controlled conditions were used to determine the movement of calcium and other cations after the application of lime, calcium oxide, gypsum and a mixture of Ume and gypsum, compared with a control treatment. Two Oxisols with different textures were used: clayey and silty. Rigid polyvinyl chloride (PVC columns (length, 45cm; diam, 5cm were used, applying 1.8 1 of water to each divided into four applications. Exchangeable cations were determined in the drainage water in 4 periods and in 5 dephts of the soil columns at the end of the experiment. The results showed that losses of Ca2+, Mg2+, K+ and A1(3+, were higher in the treatments with gypsum and lime plus gypsum. Amendments h'ke lime and calcium oxide did not promote significant losses

  5. Changes in Soil Chemical Properties and Lettuce Yield Response Following Incorporation of Biochar and Cow Dung to Highly Weathered Acidic Soils

    DEFF Research Database (Denmark)

    Agyei Frimpong, Kwame; Amoakwah, Emmanuel; Osei, Benjamin A

    2016-01-01

    Soil fertility decline is a major biophysical constraint to crop production in Sub-Saharan Africa. Therefore, there is an urgent need for sustainable soil fertility replenishment strategies to improve soil quality for enhanced crop production. In a laboratory incubation experiment, biochar (2......% and 5%) and cow dung (20 tons ha-1) were applied singly, and 2% biochar was applied in combination with two rates of cow dung (10 and 20 tons ha-1) in a coastal savanna soil repacked at a bulk density of 1.4 g cm-3 at a constant soil water filled capacity of 60% for 40 days. The same treatments were...... imposed on two highly weathered, acidic soils from the coastal savanna and tropical rainforest agroecological zones of Ghana, respectively, to elucidate their effect on yield of lettuce. The study showed that application of biochar solely or in combination with cow dung increased soil pH, total organic...

  6. Partially saturated granular column collapse

    Science.gov (United States)

    Turnbull, Barbara; Johnson, Chris

    2017-04-01

    Debris flows are gravity-driven sub-aerial mass movements containing water, sediments, soil and rocks. These elements lead to characteristics common to dry granular media (e.g. levee formation) and viscous gravity currents (viscous fingering and surge instabilities). The importance of pore fluid in these flows is widely recognised, but there is significant debate over the mechanisms of build up and dissipation of pore fluid pressure within debris flows, and the resultant effect this has on dilation and mobility of the grains. Here we specifically consider the effects of the liquid surface in the flow. We start with a simple experiment constituting a classical axisymmetric granular column collapse, but with fluid filling the column up to a depth comparable to the depth of grains. Thus, as the column collapses, capillary forces may be generated between the grains that prevent dilation. We explore a parameter space to uncover the effects of fluid viscosity, particle size, column size, aspect ratio, grain shape, saturation level, initial packing fraction and significantly, the effects of fine sediments in suspension which can alter the capillary interaction between wetted macroscopic grains. This work presents an initial scaling analysis and attempts to relate the findings to current debris flow modelling approaches.

  7. 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,…

  8. Dissolution of hardened wood ash in forest soils. Studies in a column experiment; Haerdade vedaskors upploesning i skogsjord. En studie i kolonnfoersoek. Ramprogram Askaaterfoering

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, Jan [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Soil Sciences

    1996-12-31

    Dissolution of hardened and crushed ashes was studied in a column experiment during leaching with artificial rain water corresponding to 5 year-precipitations. The ashes studied were a CFB ash from Perstorp and a bottom ash from Ljungby that were added in amounts corresponding to 4 tonnes per hectare. Assuming that the studied ashes are representative and that the results can be transferred to field conditions, the most important conclusions that can be drawn are summarized in the following way: Hardened and crushed ashes are broken down relatively slowly, which particularly applies to the coarse fraction. The fine fraction of the Perstorp ashes has a good liming effect at the same time as the risk for large pH-increases appears to be small. As regards the macro-nutrients Ca and K (not the Ljungby ashes), the amounts released are probably sufficient from a forest vitalization viewpoint. As regards Mg and P, this is less certain. The heavy metals appear to be released relatively slowly and most of them are bound in non-exchangeable form in the mor layer. The exception is Cd that tends to be absorbed in the mor layer to a minor extent but which, on the other hand, is not released from the ashes in any greater amounts. The greatest risk for increased concentrations of soluble heavy metals appears to be the mobilization of part of the mor layer`s reserve as a result of the salt effect of the ashes. However, this is a temporary effect. 17 refs, 18 figs, 6 tabs Figs and tabs with text in English

  9. Simulação do deslocamento de potássio em colunas verticais de solo não-saturado Potassium displacement simulation in vertical columns of unsaturated soil

    Directory of Open Access Journals (Sweden)

    Jarbas H. Miranda

    2005-12-01

    Full Text Available O estudo do transporte de água e potássio em solo não-saturado é importante, tanto do ponto de vista do ambiente quanto do econômico. Assim sendo, o uso da modelagem computacional é importante, pois permite de maneira precisa e rápida o monitoramento do deslocamento de solutos, importante na prevenção de impactos ao ambiente. No presente trabalho, teve-se o objetivo de avaliar a simulação do deslocamento do íon potássio em colunas de solo não-saturado, utilizando o modelo MIDI, bem como apresentar a determinação dos parâmetros de transporte do íon potássio em um Latossolo Vermelho-Amarelo, fase arenosa. Concluiu-se que o modelo foi capaz de simular de maneira satisfatória o perfil de umidade e o deslocamento do íon potássio.Water and solute transport studies in unsaturated soil are important for both economical and environmental points of view and, in this sense, it should be emphasized the increase of agricultural use of urban and industrial residues, to the water resources and fertilizers saving. Thus, the computational modeling use is important, because it allows the monitoring of solute displacement, necessary to the environmental impacts prevention in a precise and fast way. The main objective of the present work is to simulate the displacement of potassium ion in unsaturated soil columns, using the MIDI model, as well as to present transport parameters determination of the potassium ion in a Red Yellowish Latossol, sandy phase. The obtained results allowed concluding that the model was capable to adequately simulate the potassium ion displacement.

  10. Multiple pixel-scale soil water retention curves quantified by neutron radiography

    Science.gov (United States)

    Kang, M.; Perfect, E.; Cheng, C. L.; Bilheux, H. Z.; Lee, J.; Horita, J.; Warren, J. M.

    2014-03-01

    The soil water retention function is needed for modeling multiphase flow in porous media. Traditional techniques for measuring the soil water retention function, such as the hanging water column or pressure cell methods, yield average water retention data which have to be modeled using inverse procedures to extract relevant point parameters. In this study, we have developed a technique for directly measuring multiple point (pixel-scale) water retention curves for a repacked sand material using 2-D neutron radiography. Neutron radiographic images were obtained under quasi-equilibrium conditions at nine imposed basal matric potentials during monotonic drying of Flint sand at the High Flux Isotope Reactor (HFIR) Cold Guide (CG) 1D beamline at Oak Ridge National Laboratory. All of the images were normalized with respect to an image of the oven dry sand column. Volumetric water contents were computed on a pixel by pixel basis using an empirical calibration equation after taking into account beam hardening and geometric corrections. Corresponding matric potentials were calculated from the imposed basal matric potential and pixel elevations. Volumetric water content and matric potential data pairs corresponding to 120 selected pixels were used to construct 120 point water retention curves. Each curve was fitted to the Brooks and Corey equation using segmented non-linear regression in SAS. A 98.5% convergence rate was achieved resulting in 115 estimates of the four Brooks and Corey parameters. A single Brooks and Corey point water retention function was constructed for Flint sand using the median values of these parameter estimates. This curve corresponded closely with the point Brooks and Corey function inversely extracted from the average water retention data using TrueCell. Forward numerical simulations performed using HYDRUS 1-D showed that the cumulative outflows predicted using the point Brooks and Corey functions from both the direct (neutron radiography) and

  11. Spiral multicapillary columns

    Science.gov (United States)

    Efimenko, A. P.; Naumenko, I. I.; Soboleva, V. K.

    2008-08-01

    It was shown in a theoretical study and confirmed by experiment that a spiral multicapillary column had maximum efficiency if the bunch of capillaries was additionally coiled around its longitudinal axis to produce an integral number of coils. This technique made it possible to manufacture gas-chromatographic columns with performance as high as 12 to 16 thousand theoretical plates. These columns can find various applications, especially if quick separation is required.

  12. Research on critical placement height of gravel column reinforced soft soil foundations%碎石桩处理软土地基临界填筑高度的研究

    Institute of Scientific and Technical Information of China (English)

    陈继彬; 赵其华; 彭社琴

    2015-01-01

    目前计算碎石桩处理软土地基临界填筑高度的方法并不完善,没有考虑软基经碎石桩处理后复合地基强度的增加和地基排水固结能力的提高,基于此,依据固结理论,引入碎石桩复合地基固结计算的简化方法,修正按变形控制的临界填筑高度计算公式;并结合四川省遂-资高速公路软基变形监测数据,得出软基厚度在6.5~11.0 m范围内,观测所得的临界填筑高度为4.5~6.5 m,该观测值与修正公式计算值差异性不显著,证实所推导的解析式是切实可行的;在此基础上,初步探讨影响路堤临界填筑高度变化的因素,得出软基厚度、桩间距对其影响较为明显。%Calculation methods for the critical placement height of gravel column reinforced soft soil foundations are not perfect at present. The traditional calculation methods do not take the improvement of composite foundation's strength and the enhancement of foundation's drainage consolidation ability into account. Based on the consolidation theory, the simplified method of consolidation calculation of gravel column composite foundation is introduced, and it modifies the formula of the critical placement height according to the deformation control. Analyzing the settlement deformation observation data of the soft ground distributed along the Suining-Ziyang expressway in Sichuan province, results show that the thickness of clay in the study area is within 6.5-11 m and the observation value of critical placement height ranges from 4.5 to 6.5 m. The difference between observation values and calculation values with modified formula is±(0.1-0.4)m. It verifies that the formula deduced in this paper is applicable. Based on these, the factors influencing the critical placement height were discussed and it was found that the thickness of soft soil and the column spacing have more obvious influences on the critical placement height than other factors.

  13. Deslocamento miscível de nitrato e fosfato proveniente de água residuária da suinocultura em colunas de solo Miscible displacement of nitrate and phosphate from swine wastewater in soil columns

    Directory of Open Access Journals (Sweden)

    Marcelo H. Anami

    2008-02-01

    Full Text Available A fertirrigação com águas residuárias da suinocultura vem sendo muito difundida no País, principalmente na região sul do Brasil, entretanto, o alto potencial poluidor dos dejetos pode tornar-se uma ameaça de contaminação de solos e águas superficiais e subterrâneas se utilizados em quantidades excessivas. Neste trabalho o objetivo principal foi avaliar o processo de lixiviação de íons nitrato e fosfato em colunas de solo, obtendo-se os coeficientes de dispersão hidrodinâmico e o fator de retardamento para a determinação do potencial de contaminação dos lençóis de água subterrâneos. Verificou-se, ainda, o efeito da aplicação de águas residuárias da suinocultura tratada com reatores anaeróbios sobre as propriedades físico-químicas do solo, cujos resultados indicaram que o potencial de contaminação dos lençóis de água subterrâneos pelo íon nitrato é elevado, ao contrário do que ocorre com o íon fosfato, que apresentou baixo potencial de contaminação em função da sua alta reatividade.Fertigation with wastewater from swine is very much used, mainly in the southern region of Brazil. However, the high polluting potential of these wastewaters represents a threat of soil contamination of surface and underground waters if used in excessive amounts. The objective of this work was to evaluate the leaching process of nitrate and phosphate ions in soil columns, getting the hydrodynamic dispersion coefficient and factor of retardation and potential of contamination of underground water. The effect of wastewater application on physical and chemical properties of the soil was verified. The results showed that the potential for contamination of underground water by nitrate ions is high, in contrast to what occurs with phosphate ions that presented low potential of contamination due to their high reactivity.

  14. 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

  15. Glass-silicon column

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Conrad M.

    2003-12-30

    A glass-silicon column that can operate in temperature variations between room temperature and about 450.degree. C. The glass-silicon column includes large area glass, such as a thin Corning 7740 boron-silicate glass bonded to a silicon wafer, with an electrode embedded in or mounted on glass of the column, and with a self alignment silicon post/glass hole structure. The glass/silicon components are bonded, for example be anodic bonding. In one embodiment, the column includes two outer layers of silicon each bonded to an inner layer of glass, with an electrode imbedded between the layers of glass, and with at least one self alignment hole and post arrangement. The electrode functions as a column heater, and one glass/silicon component is provided with a number of flow channels adjacent the bonded surfaces.

  16. Mobilidade de solutos em colunas de solo com água residuária doméstica e de suinocultura Displacement of solutes in soil columns with domestic and swine raising wastewater

    Directory of Open Access Journals (Sweden)

    Joelma S. dos Santos

    2010-11-01

    Full Text Available Com o objetivo de avaliar o fator de retardamento, coeficiente de dispersão-difusão e curva de efluente dos íons cálcio, magnésio, sódio e potássio das águas residuárias de origem doméstica tratada e de suinocultura, realizou-se um experimento em laboratório com colunas de solos Argissolo Vermelho Amarelo e Neossolo Regolítico. Com o auxílio de frascos de Mariotte cerca de dois volumes de poros de água destilada foram passados nas colunas; em seguida, interligou-se outro frasco contendo as águas residuárias, doméstica e da suinocultura, o que lixiviou 3,75 volume de poros divididos em 25 alíquotas, totalizando 600 amostras. Os resultados permitiram concluir que os fatores de retardamento foram mais altos para o sódio no solo Argissolo Vermelho Amarelo e para o íon magnésio no Neossolo Regolítico, lixiviados com água residuária doméstica tratada. Em referência à água residuária da suinocultura, os maiores valores foram calculados para o íon magnésio, nos dois solos; quanto aos coeficientes de dispersão-difusão, os maiores valores foram registrados no Neossolo Regolítico, independentemente do tipo de água utilizada.With the objective of evaluating the parameters of transport retardation factor, dispersion-diffusion coefficient and effluent curves of the íons calcium, magnesium, sodium and potassium, present in domestic and swine raising wastewater, an experiment was conducted in laboratory with columns of Red Yellow Argisol and Regolithic Fluvisol. With the aid of flasks of Mariotte around two pore volumes of distilled water were passed in the columns; soon after, another flask was interconnected containing the wastewaters which leached 3.75 volume of pores divided in 25 aliqnot, totaling 600 samples. The obtained results lead to the conclussion that the retardation factors were higher for the sodium in the Red Yellow Argisol and for the magnesium in Regolithic Fluvisol leached with treated domestic wastewater

  17. Computational prediction and experimental characterization of a "size switch type repacking" during the evolution of dengue envelope protein domain III (ED3).

    Science.gov (United States)

    Elahi, Montasir; Islam, Monirul M; Noguchi, Keiichi; Yohda, Masafumi; Toh, Hiroyuki; Kuroda, Yutaka

    2014-03-01

    Dengue viruses (DEN) are classified into four serotypes (DEN1-DEN4) exhibiting high sequence and structural similarities, and infections by multiple serotypes can lead to the deadly dengue hemorrhagic fever. Here, we aim at characterizing the thermodynamic stability of DEN envelope protein domain III (ED3) during its evolution, and we report a structural analysis of DEN4wt ED3 combined with a systematic mutational analysis of residues 310 and 387. Molecular modeling based on our DEN3 and DEN4 ED3 structures indicated that the side-chains of residues 310/387, which are Val(310)/Ile(387) and Met(310)/Leu(387) in DEN3wt and DEN4wt, respectively, could be structurally compensated, and that a "size switch type repacking" might have occurred at these sites during the evolution of DEN into its four serotypes. This was experimentally confirmed by a 10°C and 5°C decrease in the thermal stability of, respectively, DEN3 ED3 variants with Met(310)/Ile(387) and Val(310)/Leu(387), whereas the variant with Met(310)/Leu(387), which contains a double mutation, had the same stability as the wild type DEN3. Namely, the Met310Val mutation should have preceded the Leu387Ile mutation in order to maintain the tight internal packing of ED3 and thus its thermodynamic stability. This view was confirmed by a phylogenetic reconstruction indicating that a common DEN ancestor would have Met(310)/Leu(387), and the intermediate node protein, Val(310)/Leu(387), which then mutated to the Val(310)/Ile(387) pair found in the present DEN3. The hypothesis was further confirmed by the observation that all of the present DEN viruses exhibit only stabilizing amino acid pairs at the 310/387 sites.

  18. Potencial de lixiviação de herbicidas utilizados na cultura do algodão em colunas de solo Leaching potential of herbicides used in cotton crop under soil column conditions

    Directory of Open Access Journals (Sweden)

    M.H Inoue

    2010-12-01

    potential of four herbicides commonly used in preemergence cotton weed control, in samples of two soils from Campo Novo do Parecis-MT (RQ-sandy texture and Tangará da Serra-MT (LV-clay texture. Thus, a bioassay technique in soil columns was adopted, in which water depths of 0, 20, 40, 60, 80 and 100 mm were simulated after application of alachlor (RQ 2.40; LV 3.36 kg ha-1, oxyfluorfen (RQ 0.48; LV 0.72 kg ha-1, prometryne (RQ 0.75; LV 1.50 kg ha-1 and S-metolachlor (RQ 1.20; LV 1.44 kg ha-1. For soil samples with sandy texture (RQ, water depths of 80 and 100 mm led to leaching down to layers of 10-15 cm for alachlor and 15-20 cm for S-metolachlor.Regardless of the irrigation depth applied in the RQ samples, oxyfluorfen did not exceed the depth of 5-10 cm and prometryne could be detected at the depth of 10-15 cm only at water depth of 100 mm. In columns filled with clay soil (LV, oxyfluorfen did not move beneath the surface layer, even under the highest water depths and prometryne reached the depth of 5-10 cm under 80 and 100 mm. The herbicides alachlor and S-metolachlor reached 10-15 cm depth under water depths of 80 and 100 mm in the LV. A more intense downward movement of the herbicide molecules was found in sandy soil samples (RQ than in clay texture soil samples (LV.

  19. Perdas de nutrientes via subsuperfície em colunas de solo sob fertilização mineral e orgânica Nutrient losses via leaching from soil columns submitted to mineral and organic fertilization

    Directory of Open Access Journals (Sweden)

    Ricardo Prado Piovesan

    2009-08-01

    application on NH4+, NO3-, P and K leaching. For this evaluation, undisturbed soil columns were collected from a seven-year field experiment that consisted of 12 treatments, resulting from the combinations of four doses of dairy slurry with three doses of mineral fertilizers. The study has been conducted on an Oxisol under no-till system with a crop rotation including sorghum, corn, oat and ryegrass. The leaching experiment was conducted in a laboratory with the undisturbed soil columns collected in the field experiment. In the laboratory, these soil columns, analogously to the respective field treatments, were treated with dairy slurry manure (0, 30, 60 and 90 m³ ha-¹ applied in a single dose and mineral fertilizers (0, 50 and 100 % of the recommended dose for corn - 120 kg of N, 60 kg of P2O5 and 60 kg of K2O per ha application. Immediately after manure and fertilizer application, the percolated water was sampled and analyzed in five continuous periods, totalling 516 mm, which corresponded to approximately three pore volumes. An increase of NH4-N, P, and K with increasing manure doses and an increment in NO3-N and K with the higher mineral fertilizer doses was observed. However, in general, except for NO3-N, the NH4-N and P concentrations were below the limit value determined by the Brazilian legislation, indicating the importance of soil-water infiltration to reduce the manure pollution potential.

  20. 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

  1. Influences of DOM and pH on PAHs Migrations in Soil Columns%DOM及pH对典型PAHs在土壤中迁移影响模拟实验研究

    Institute of Scientific and Technical Information of China (English)

    乔肖翠; 何江涛; 杨蕾; 邹合萍

    2014-01-01

    影响多环芳烃(PAHs)在土壤中垂向迁移的因素很多,通过柱实验模拟研究了溶解性有机质(DOM)浓度及pH对多环芳烃在土壤中迁移及转化的影响,以氯离子做示踪剂进行校正,探讨了不同浓度DOM及pH对多环芳烃迁移的影响。结果表明,校正后的多环芳烃迁移速率随着DOM浓度增加呈逐渐增大趋势,与空白柱对照可得低浓度的DOM由于累积吸附与共吸附作用对多环芳烃的迁移起抑制作用,随着DOM浓度增加,抑制作用逐渐减弱,当浓度达到一定程度时,DOM形成表面活性剂胶体束,多环芳烃进入胶体束内部,从而迁移速率加快。当pH为6、8、10时多环芳烃的迁移速率与空白柱相比均较大,且pH为8、10时多环芳烃迁移速率大于pH为6时的迁移速率,由此可见pH会影响多环芳烃迁移速率,其原因为pH的改变会影响DOM所带电荷的电性,当pH升高到中性或碱性时由于空间排斥理论,DOM的迁移会加快,从而影响多环芳烃的迁移速率。%Vertical migrations of polycyclic aromatic hydrocarbons(PAHs)in soils are influenced by many factors. In a simulated experiment, vertical migrations of PAHs in soil columns were investigated at different levels of DOM and pH. Chloride ion(Cl-)was used to correct the migration rates of PAHs. The migration rates of PAHs were influenced by DOM concentrations. At low concentrations, DOM restrained the vertical migrations of PAHs, due to its cumulative adsorption and co-adsorption. At high concentrations, however, DOM formed surfactant colloids, and the PAHs could enter the colloids, leading to increased migrations. The migrations of PAHs in the columns increased with in-creasing pH values, due to promoted electrostatic exclusion from more charges of DOM from the dissociation at higher pH.

  2. Meta-analysis of the effects of soil properties, site factors and experimental conditions on solute transport

    Directory of Open Access Journals (Sweden)

    J. K. Koestel

    2012-06-01

    Full Text Available Preferential flow is a widespread phenomenon that is known to strongly affect solute transport in soil, but our understanding and knowledge is still poor of the site factors and soil properties that promote it. To investigate these relationships, we assembled a database from the peer-reviewed literature containing information on 733 breakthrough curve experiments under steady-state flow conditions. Most of the collected experiments (585 of the 733 datasets had been conducted on undisturbed soil columns, although some experiments on repacked soil, clean sands, and glass beads were also included. In addition to the apparent dispersivity, we focused our attention on three indicators of preferential solute transport: namely the 5%-arrival time, the holdback factor, and the ratio of piston-flow and average transport velocities. Our results suggest that, in contrast to the 5%-arrival time and the holdback factor, the piston-flow to transport velocity ratio is not related to preferential macropore transport but rather to the exclusion or retardation of the applied tracer. Confirming that the apparent longitudinal dispersivity is positively correlated with the travel distance of the tracer, our results also illustrate that this relationship is refined if the normalized 5%-tracer arrival time is also taken into account. In particular, we found that the degree of preferential solute transport increases with apparent dispersivity and decreases with travel distance. A similar but weaker relationship was observed between apparent dispersivity, 5%-tracer arrival time, and lateral observation scale, such that the degree of preferential transport increases with lateral observation scale. However, we also found that the travel distance and the lateral observation scale in the investigated dataset are correlated, which makes it difficult to distinguish their influence on these transport characteristics. We also found that the strength of preferential transport

  3. 氯氰菊酯在土柱淋滤实验中的迁移行为%Research on the Migration Behavior of Cypermethrin in the Leaching Experiment by Soil Column

    Institute of Scientific and Technical Information of China (English)

    石健; 张彦; 邹开云; 杨存满; 高尚

    2013-01-01

    通过室内一维土柱淋滤实验,选择氯氰菊酯为淋滤液,研究其在不同介质中的穿透行为,探讨不同介质自身特性对氯氰菊酯纵向弥散行为的影响。实验依据自然降雨强度确定喷淋强度,通过改变充填介质的种类比较氯氰菊酯与氯离子在不同介质中的穿透曲线的差异。结果表明:以乳油形式广泛应用于田间的氯氰菊酯在土柱内的穿透曲线与氯离子十分接近,即氯氰菊酯在水中的迁移性能良好,对地下水有一定威胁。土壤有机质含量会引起弥散系数的降低,实验选择的2种喷淋强度对氯氰菊酯的弥散系数影响不大。%In this paper,engaged the soil column and chose Cypermethrin as tracer,the breakthrough behavior of tracer in different porous media was studied.,and discussed the influence of the longitudinal dispersion coeffi-cient of Cypermethrin by the characteristics of the porous medias. Leaching experiments simulated natural rainfall intensity as leaching intensity,compared breakthrough curves of Cypermethrin and chloride ion by changing the filled medium. The results showed that the breakthrough curves of Cypermethrin and chloride ion were very close,which meant the Cypermethrin had higher transport properties in water and had a certain threat to pollute groundwater. The content of soil organic matter was higher,the diffusion coefficient was lower. The leaching inten-sity which chose by the experiment had little effect on the diffusion coefficient of Cypermethrin.

  4. Numerical analysis of soft clay performance reinforced by geosynthetics encased stone columns

    Science.gov (United States)

    Nagy, Nabil M.

    2013-10-01

    To improve the behavior of stone columns, the Geosynthetics is used for encasing the stone column as reinforcement material. The Geosynthetics Encased Stone Column (GESC) system has been developed to increase the confinement effect of the ordinary stone columns, and consequently to improve the load carrying capacity of stone columns. In this paper, finite element based numerical study has been carried out using ABAQUS program to study the performance of the GESC systems under different conditions. The influences of some effective parameters were studied to show the improvement in soil bearing and settlement decrease for the stone column-soil system. These include the column dimensions, the encasement stiffness and shear strength of the foundation soil.

  5. Eruption column physics

    Energy Technology Data Exchange (ETDEWEB)

    Valentine, G.A.

    1997-03-01

    In this paper the author focuses on the fluid dynamics of large-scale eruption columns. The dynamics of these columns are rooted in multiphase flow phenomena, so a major part of the paper sets up a foundation on that topic that allows one to quickly assess the inherent assumptions made in various theoretical and experimental approaches. The first part is centered on a set of complex differential equations that describe eruption columns, but the focus is on a general understanding of important physical processes rather than on the mathematics. The author discusses briefly the relative merits and weaknesses of different approaches, emphasizing that the largest advances in understanding are made by combining them. He then focuses on dynamics of steady eruption columns and then on transient phenomena. Finally he briefly reviews the effects of varying behavior of the ambient medium through which an eruption column moves. These final sections will emphasize concepts and a qualitative understanding of eruption dynamics. This paper relies on principles of continuum mechanics and transport processes but does not go into detail on the development of those principles. 36 refs., 36 figs., 3 tabs.

  6. Columns in Clay

    Science.gov (United States)

    Leenhouts, Robin

    2010-01-01

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

  7. Slender CRC Columns

    DEFF Research Database (Denmark)

    Aarup, Bendt; Jensen, Lars Rom; Ellegaard, Peter

    2005-01-01

    CRC is a high-performance steel fibre reinforced concrete with a typical compressive strength of 150 MPa. Design methods for a number of structural elements have been developed since CRC was invented in 1986, but the current project set out to further investigate the range of columns for which...

  8. Lixiviação de sulfentrazone e amicarbazone em colunas de solo com adição de óleo mineral Leaching of sulfentrazone and amicarbazon in soil columns with mineral oil

    Directory of Open Access Journals (Sweden)

    T.F. Bachega

    2009-06-01

    area on a Red Latosol, using soil columns. For leaching assessment, after the accumulated rainfall of 35, 67 and 106 mm, PVC tubes of 10 cm in diameter, sliced lengthwise, were buried at the depth of 35 cm, managing to maintain the original structure of the soil. The tubes were removed, split into halves and placed in a greenhouse, where seeds of the test plant sorghum (Sorghum bicolor and morning-glory (Ipomoea nil were sown along the profile of each half of the tubes. The experimental design was randomized blocks with the treatments in split-plots with four replications. The plots consisted of two herbicides, with or without adjuvant, and a control without herbicide. The subplots were the depths (0.0-2.5; 2.5-5.0; 5.0-10, 10-15, 15-20, 20-25; 25-30; 30-35 cm. At 20 days after sowing, dry weight of the seedlings was determined. Sulfentrazone leached up to 10 cm deep, even with 106 mm of rainfall, without any differential effect of the oil. The effects were more pronounced for sorghum. Amicarbazone did not interfere in the dry weight of sorghum. For morning-glory, under a rainfall of 35 mm, the herbicide reduced seedling development, regardless of depth and without any oil effect; with 67 mm of rainfall, the herbicide leached through soil with the mineral oil, maintaining it in the most superficial layer. With 106 mm, the herbicide was totally leached and no oil effect was confirmed.

  9. Slurry bubble column hydrodynamics

    Science.gov (United States)

    Rados, Novica

    Slurry bubble column reactors are presently used for a wide range of reactions in both chemical and biochemical industry. The successful design and scale up of slurry bubble column reactors require a complete understanding of multiphase fluid dynamics, i.e. phase mixing, heat and mass transport characteristics. The primary objective of this thesis is to improve presently limited understanding of the gas-liquid-solid slurry bubble column hydrodynamics. The effect of superficial gas velocity (8 to 45 cm/s), pressure (0.1 to 1.0 MPa) and solids loading (20 and 35 wt.%) on the time-averaged solids velocity and turbulent parameter profiles has been studied using Computer Automated Radioactive Particle Tracking (CARPT). To accomplish this, CARPT technique has been significantly improved for the measurements in highly attenuating systems, such as high pressure, high solids loading stainless steel slurry bubble column. At a similar set of operational conditions time-averaged gas and solids holdup profiles have been evaluated using the developed Computed Tomography (CT)/Overall gas holdup procedure. This procedure is based on the combination of the CT scans and the overall gas holdup measurements. The procedure assumes constant solids loading in the radial direction and axially invariant cross-sectionally averaged gas holdup. The obtained experimental holdup, velocity and turbulent parameters data are correlated and compared with the existing low superficial gas velocities and atmospheric pressure CARPT/CT gas-liquid and gas-liquid-solid slurry data. The obtained solids axial velocity radial profiles are compared with the predictions of the one dimensional (1-D) liquid/slurry recirculation phenomenological model. The obtained solids loading axial profiles are compared with the predictions of the Sedimentation and Dispersion Model (SDM). The overall gas holdup values, gas holdup radial profiles, solids loading axial profiles, solids axial velocity radial profiles and solids

  10. 新型大球包膜控释肥在土壤中的淋溶特征%Leaching Characteristics of Big Spherical Coated Controlled-release Fertilizer in Soil Columns

    Institute of Scientific and Technical Information of China (English)

    李长洲; 张民; 杨越超

    2013-01-01

    Through soil columns leaching test,the leaching characteristics of big spherical coated controlled-release fertilizer used for fruit trees and the effects of fertilizer treatments on pH value,electrical conductivity of leachate and nutrients such as nitrogen,phosphorus,potassium and magnesium in leachate were studied.The results showed that the leachate pH of big spherical coated controlled-release fertilizer was significantly higher than that of the soluble fertilizer,but there was no significant difference with no fertilizer control and the other two kinds of controlled-release fertilizer treatments.In the whole leaching process,the electrical conductivity and the nutrients contents of inorganic nitrogen,water soluble phosphorus and water soluble potassium in leachate treated by the big spherical coated controlled-release fertilizer were significantly lower than that of soluble fertilizer at the earlier fractions of leaching,and were significantly higher than that of the other two kinds of controlled-release fertilizers in most fractions of leaching especially at the later fractions.The nutrients loss by leaching of inorganic nitrogen,water soluble phosphorus and water soluble potassium were 38.72%,1.91% and 24.76%,respectively.According to the above conclusions,the big spherical coated controlled-release fertilizer could decrease nutrients leaching loss,and reduce pollution of groundwater.%通过土柱淋溶模拟试验研究果树专用新型大球包膜控释肥在土体中的淋溶特征以及对土壤淋滤液pH、EC变化和N、P、K、Mg等养分淋失的影响.结果表明,新型大球包膜控释肥处理淋滤液pH值显著高于未包膜肥料处理,但与不施肥处理和其他2种控释肥处理差异不显著.在整个淋溶过程中,新型大球包膜控释肥处理淋滤液EC值和淋滤液中无机态氮、水溶性磷、水溶性钾含量在淋溶前期显著低于速效肥料处理,但在淋溶后期显著高于其他2种控释肥处

  11. Deslocamento miscível de cátions básicos provenientes da água residuária de mandioca em colunas de solo Miscible displacement of basic cations from cassava processing wastewater in soil columns

    Directory of Open Access Journals (Sweden)

    Ralini F. de Melo

    2006-06-01

    Full Text Available Objetivou-se, com este estudo, determinar os fatores de retardamento e os coeficientes de dispersão-difusão dos íons potássio, sódio, cálcio e magnésio, presentes na água residuária de fecularias ou manipueira, e simular as concentrações residentes em colunas de solos de 160 cm, pelo período de 5 h. Os ensaios foram realizados em laboratório utilizando-se colunas de percolação preenchidas com amostras de Neossolo Quartzarênico órtico espódico (RQo, Latossolo Amarelo distrófico típico (LAd e Latossolo Vermelho Amarelo distrófico típico (LVAd. A concentração dos íons no efluente foram analisados empregando-se a metodologia de deslocamento de fluidos miscíveis. Os valores mais elevados dos fatores de retardamento ocorreram no LVAd, indicando maior retenção dos íons potássio, sódio, cálcio e magnésio nesse solo. Os valores dos coeficientes dispersivos-difusivos decresceram no sentido do RQo para o LVAd, sendo que o maior valor ocorreu no RQo para o íon potássio, e o menor no LVAd, para o íon cálcio. A simulação para um período de aplicação da manipueira de 5 h, mostrou pequeno avanço dos íons na coluna do LVAd, em comparação com RQo e LAd alertando, assim, para os perigos de contaminação de águas subterrâneas ao se aplicar a manipueira nesses solos.This study aimed to determine the retardation factors and the diffusion-dispersion coefficients of the potassium, sodium, calcium and magnesium ions found in the cassava wastewater, as well as to simulate the resident concentrations in soil columns with 160 cm over a five-hours period. The trials were accomplished under laboratory conditions, by using percolation columns fulfilled with materials from the spodic ortic Quartzarenic Neosol (RQo, typical distrophic Yellow Latosol (LAd and typical distrophic Yellow Red Latosol (LVAd. The data of the ion concentrations in effluent were analyzed, by using the miscible fluid displacement methodology. The highest

  12. The Development of Gel Media and Columns for Large-Scale Chromatography of Proteins,a Historical Review

    Institute of Scientific and Technical Information of China (English)

    Jan-Christer; Janson

    2002-01-01

    Thr first dedicated protein chromatography media were introduced during the 1950s and 1960s.There was an early awareness of the possibility of using these for production applications within the biopharmaceutical industry.However,the crucial limitation was the fact that those media that were most compatible with proteins lent themselves less favourably to scaling-up.The problems were primarily physical.Thus the fibrous cellulose media showed bed cracking tendencies and the bead shaped polyacrylamide.dextran,and agarose gel media,then available, were too soft to stand the hydrodynamic forces acting in large columns,leading to bed compaction and increased pressure drop.At the time,the best solution to the latter problem,after a number of intermediary solutions were tried,was the introductionof the stacked column concept in which several short column segments were connected by small bore tubing,thus reducing the force acting on the particles in each bed com partment,However,the ultimate remedy,the introduction of chromatographic matrices that combine the desired features of adequate rigidity,macroporosity,biocompatibility,chemical stability(for CIP and SIP0and derivatizability,did not occur until the middle of the 1980s when adequately cross-linked agarose gel media such as Sepharose Fast Flow were made available.The paper also recognizes the many attempts made during the past 50 years to develop continous chromatography columns.Most of the designs are based on an annular bed or on an array of annularly arranged parallel columns continuously fed with samples in a cyclic manner.The introduction of media and columns for expanded bed adsorption followed a demand for rewer pruification steps and shorter process times.In recent years,columns have been ntroduced that allow packing and repacking without needing to open the column.The review provides an historical account of the developments that have led to the present state-of-the-art both regarding large diameter columns

  13. Behavior of Columns During Earthquakes

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The behavior of columns during earthquakes is very important since column failures may lead to additional structural failures and result in total building collapses....

  14. Determination of Two Columns Performance

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    When protein is analyzed by high performance liquid chromatography (HPLC), the selection of column is one of the most important factors. There are four quality control parameters for the column, which are theoretical plates n, capacity facto

  15. 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.

  16. A novel automated fluctuating water table column system to study redox oscillations in saturated and unsaturated media

    Science.gov (United States)

    Rezanezhad, F.; Couture, R.-M.; Kovac, R.; Van Cappellen, P.

    2012-04-01

    An automated, computer-controlled soil column experimental setup was developed to simulate in detail the effects of water table dynamics on the biogeochemical transformations of nutrients and other redox-sensitive chemical species at the interface between groundwater and surface waters. The experiments were conducted using two parallel soil columns, one under stable and the other under fluctuating water table conditions. The water table in the soil columns was controlled by an automated multi-channel pump connected to two equilibrium and storage columns. In the stable column, the water table was maintained at -20 cm below the soil surface while it fluctuated between the soil surface and -45 cm in the fluctuating column at a rate of 4.8 cm/d. Redox potential (Eh), pH profiles were measured continuously using high temporal resolution microsensors (10 μm glass tip) installed into the columns at different depths. The results show striking geochemical contrasts between the fluctuating and the stable columns, demonstrating that the setup is able to impose redox potential oscillations ranging from oxidizing (~+700 mv) to reducing (~-200 mv) conditions. CO2 fluxes were monitored in the headspace above the soil surface using a LICOR LI-8100 automated soil CO2 flux system. The mean CO2 emission in the stable water table column was ~20 ppm/min. In the fluctuating soil column, the CO2 flux varied between 4 and 110 ppm/min and the lowest were measured at the highest water level. Water samples obtained from micro-Rhizon samplers installed into the columns at various depths. Additionally, the physical, chemical and microbial characteristics of the media were characterized by centimetre scale slicing of the soil columns at the end of the experiment. The impacting of these oscillations on the distribution of chemical species will be discussed in term of the interactions between soils, solutes, microbial activity, and hydrology.

  17. Column: Every Last Byte

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel

    2011-06-01

    Full Text Available Inheritance powder is the name that was given to poisons, especially arsenic, that were commonly used in the 17th and early 18th centuries to hasten the death of the elderly. For most of the 17th century, arsenic was deadly but undetectable, making it nearly impossible to prove that someone had been poisoned. The first arsenic test produced a gas—hardly something that a scientist could show to a judge. Faced with a growing epidemic of poisonings, doctors and chemists spent decades searching for something better.(see PDF for full column

  18. Prediction of axial limit capacity of stone columns using dimensional analysis

    Science.gov (United States)

    Nazaruddin A., T.; Mohamed, Zainab; Mohd Azizul, L.; Hafez M., A.

    2017-08-01

    Stone column is the most favorable method used by engineers in designing work for stabilization of soft ground for road embankment, and foundation for liquid structure. Easy installation and cheaper cost are among the factors that make stone column more preferable than other method. Furthermore, stone column also can acts as vertical drain to increase the rate of consolidation during preloading stage before construction work started. According to previous studied there are several parameters that influence the capacity of stone column. Among of them are angle friction of among the stones, arrangement of column (two pattern arrangement most applied triangular and square), spacing center to center between columns, shear strength of soil, and physical size of column (diameter and length). Dimensional analysis method (Buckingham-Pi Theorem) has used to carry out the new formula for prediction of load capacity stone columns. Experimental data from two previous studies was used for analysis of study.

  19. Why Hexagonal Basalt Columns?

    Science.gov (United States)

    Hofmann, Martin; Anderssohn, Robert; Bahr, Hans-Achim; Weiß, Hans-Jürgen; Nellesen, Jens

    2015-10-09

    Basalt columns with their preferably hexagonal cross sections are a fascinating example of pattern formation by crack propagation. Junctions of three propagating crack faces rearrange such that the initial right angles between them tend to approach 120°, which enables the cracks to form a pattern of regular hexagons. To promote understanding of the path on which the ideal configuration can be reached, two periodically repeatable models are presented here involving linear elastic fracture mechanics and applying the principle of maximum energy release rate. They describe the evolution of the crack pattern as a transition from rectangular start configuration to the hexagonal pattern. This is done analytically and by means of three-dimensional finite element simulation. The latter technique reproduces the curved crack path involved in this transition.

  20. Column: File Cabinet Forensics

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel

    2011-12-01

    Full Text Available Researchers can spend their time reverse engineering, performing reverse analysis, or making substantive contributions to digital forensics science. Although work in all of these areas is important, it is the scientific breakthroughs that are the most critical for addressing the challenges that we face.Reverse Engineering is the traditional bread-and-butter of digital forensics research. Companies like Microsoft and Apple deliver computational artifacts (operating systems, applications and phones to the commercial market. These artifacts are bought and used by billions. Some have evil intent, and (if society is lucky, the computers end up in the hands of law enforcement. Unfortunately the original vendors rarely provide digital forensics tools that make their systems amenable to analysis by law enforcement. Hence the need for reverse engineering.(see PDF for full column

  1. European Analytical Column

    DEFF Research Database (Denmark)

    Karlberg, B.; Grasserbauer, M.; Andersen, Jens Enevold Thaulov

    2009-01-01

    The European Analytical Column has once more invited a guest columnist to give his views on various matters related to analytical chemistry in Europe. This year, we have invited Professor Manfred Grasserbauer of the Vienna University of Technology to present some of the current challenges...... for European analytical chemistry. During the period 2002–07, Professor Grasserbauer was Director of the Institute for Environment and Sustainability, Joint Research Centre of the European Commission (EC), Ispra, Italy. There is no doubt that many challenges exist at the present time for all of us representing...... a major branch of chemistry, namely analytical chemistry. The global financial crisis is affecting all branches of chemistry, but analytical chemistry, in particular, since our discipline by tradition has many close links to industry. We have already noticed decreased industrial commitment with respect...

  2. SPIRAL CONTACTOR FOR SOLVENT EXTRACTION COLUMN

    Science.gov (United States)

    Cooley, C.R.

    1961-06-13

    The patented extraction apparatus includes a column, perforated plates extending across the column, liquid pulse means connected to the column, and an imperforate spiral ribbon along the length of the column.

  3. Compact electron beam focusing column

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-07-13

    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 2-D 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.

  4. Contribution of soil fauna to soil functioning in degraded environments: a multidisciplinary approach

    Science.gov (United States)

    Gargiulo, Laura; Mele, Giacomo; Moradi, Jabbar; Kukla, Jaroslav; Jandová, Kateřina; Frouz, Jan

    2016-04-01

    The restoration of the soil functions is essential for the recovery of highly degraded sites and, consequently, the study of the soil fauna role in the soil development in such environments has great potential from a practical point of view. The soils of the post-mining sites represent unique models for the study of the natural ecological succession because mining creates similar environments characterized by the same substrate, but by different ages according to the year of closure of mines. The aim of this work was to assess the contribution of different species of macrofauna on the evolution of soil structure and on the composition and activity of the microbial community in soil samples subjected to ecological restoration or characterized by spontaneous ecological succession. For this purpose, an experimental test was carried out in two sites characterized by different post-mining conditions: 1) natural succession, 2) reclamation with planting trees. These sites are located in the post-mining area of Sokolov (Czech Republic). For the experimental test repacked soil cores were prepared in laboratory with sieved soil sampled from the two sites. The soil cores were prepared maintaining the sequence of soil horizons present in the field. These samples were inoculated separately with two genera of earthworms (Lumbricus and Aporrectodea) and two of centipedes (Julida and Polydesmus). In particular, based on their body size, were inoculated for each cylinder 2 individuals of millipedes, 1 individual of Lumbricus and 4 individuals of Aporrectodea. For each treatment and for control samples 5 replicates were prepared and all samples were incubated in field for 1 month in the two original sampling sites. After the incubation the samples were removed from the field and transported in laboratory in order to perform the analysis of microbial respiration, of PLFA (phospholipid-derived fatty acids) and ergosterol contents and finally for the characterization of soil structure

  5. Practical design of stepped columns

    NARCIS (Netherlands)

    Girao Coelho, A.M.; Simao, P.D.; Bijlaard, F.S.K.

    2012-01-01

    This paper deals with buckling aspects of the design of stepped columns in heavy mill buildings. In these structures, columns have to carry significant axial loads that usually act eccentrically and strength reducing bending moments due to lateral loads. A simple physical model for buckling behaviou

  6. An Undergraduate Column Chromatography Experiment.

    Science.gov (United States)

    Danot, M.; And Others

    1984-01-01

    Background information, list of materials needed, and procedures used are provided for an experiment designed to introduce undergraduate students to the theoretical and technical aspects of column chromatography. The experiment can also be shortened to serve as a demonstration of the column chromatography technique. (JN)

  7. Mush Column Magma Chambers

    Science.gov (United States)

    Marsh, B. D.

    2002-12-01

    Magma chambers are a necessary concept in understanding the chemical and physical evolution of magma. The concept may well be similar to a transfer function in circuit or time series analysis. It does what needs to be done to transform source magma into eruptible magma. In gravity and geodetic interpretations the causative body is (usually of necessity) geometrically simple and of limited vertical extent; it is clearly difficult to `see' through the uppermost manifestation of the concentrated magma. The presence of plutons in the upper crust has reinforced the view that magma chambers are large pots of magma, but as in the physical representation of a transfer function, actual magma chambers are clearly distinct from virtual magma chambers. Two key features to understanding magmatic systems are that they are vertically integrated over large distances (e.g., 30-100 km), and that all local magmatic processes are controlled by solidification fronts. Heat transfer considerations show that any viable volcanic system must be supported by a vertically extensive plumbing system. Field and geophysical studies point to a common theme of an interconnected stack of sill-like structures extending to great depth. This is a magmatic Mush Column. The large-scale (10s of km) structure resembles the vertical structure inferred at large volcanic centers like Hawaii (e.g., Ryan et al.), and the fine scale (10s to 100s of m) structure is exemplified by ophiolites and deeply eroded sill complexes like the Ferrar dolerites of the McMurdo Dry Valleys, Antarctica. The local length scales of the sill reservoirs and interconnecting conduits produce a rich spectrum of crystallization environments with distinct solidification time scales. Extensive horizontal and vertical mushy walls provide conditions conducive to specific processes of differentiation from solidification front instability to sidewall porous flow and wall rock slumping. The size, strength, and time series of eruptive behavior

  8. Application of column tests and electrical resistivity methods for leachate transport monitoring

    Directory of Open Access Journals (Sweden)

    Wychowaniak Dorota

    2015-09-01

    Full Text Available Development of the human civilization leads to the pollution of environment. One of the contamination which are a real threat to soil and groundwater are leachates from landfills. In this paper the solute transport through soil was considered. For this purpose, the laboratory column tests of chlorides tracer and leachates transport on two soil samples have been carried out. Furthermore, the electrical resistivity method was applied as auxiliary tool to follow the movements of solute through the soil column what allowed to compare between the results obtained with column test method and electrical resistivity measurements. Breakthrough curves obtained by conductivity and resistivity methods represents similar trends which leads to the conclusion about the suitability of electrical resistivity methods for contamination transport monitoring in soil-water systems.

  9. Beneath aggregate stability - quantifying thermodynamic properties that drive soil structure dynamics

    Science.gov (United States)

    Hallett, Paul; Ogden, Mike; Karim, Kamal; Schmidt, Sonja; Yoshida, Shuichiro

    2014-05-01

    Soil aggregates are a figment of your energy input and initial boundary conditions, so the basic thermodynamics that drive soil structure formation are needed to understand soil structure dynamics. Using approaches from engineering and materials science, it is possible quantify basic thermodynamic properties, but at present tests are generally limited to highly simplified, often remoulded, soil structures. Although this presents limitations, the understanding of underlying processes driving soil structure dynamics is poor, which could be argued is due to the enormity of the challenge of such an incredibly complex system. Other areas of soil science, particularly soil water physics, relied on simplified structures to develop theories that can now be applied to more complex pore structures. We argue that a similar approach needs to gain prominence in the study of soil aggregates. An overview will be provided of approaches adapted from other disciplines to quantify particle bonding, fracture resistance, rheology and capillary cohesion of soil that drive its aggregation and structure dynamics. All of the tests are limited as they require simplified soil structures, ranging from repacked soils to flat surfaces coated with mineral particles. A brief summary of the different approaches will demonstrate the benefits of collecting basic physical data relevant to soil structure dynamics, including examples where they are vital components of models. The soil treatments we have tested with these engineering and materials science approaches include field soils from a range of management practices with differing clay and organic matters contents, amendment and incubation of soils with a range of microorganisms and substrates in the laboratory, model clay-sand mixes and planar mineral surfaces with different topologies. In addition to advocating the wider adoption of these approaches, we will discuss limitations and hope to stimulate discussion on how approaches could be improved

  10. Water Column Sonar Data Collection

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The collection and analysis of water column sonar data is a relatively new avenue of research into the marine environment. Primary uses include assessing biological...

  11. Size- and concentration-dependent deposition of fluorescent silica colloids in saturated sand columns: transport experiments and modeling.

    Science.gov (United States)

    Vitorge, Elsa; Szenknect, Stéphanie; Martins, Jean M F; Gaudet, Jean-Paul

    2013-08-01

    This study investigates the size and concentration effects on the transport of silica colloids in columns of sandy aquifer material. Colloid transport experiments were performed with specifically developed fluorescent labeled silica colloids in columns of a repacked natural porous medium under hydro-geochemical conditions representative of sandy aquifers. Breakthrough curves and vertical deposition profiles of colloids were measured for various colloid concentrations and sizes. The results showed that for a given colloid concentration injected, deposition increased when increasing the size of the colloids. For a given colloid size, retention was also shown to be highly concentration-dependent with a non-monotonous pattern presenting low and high concentration specificities. Deposition increases when increasing both size and injected concentration, until a threshold concentration is reached, above which retention decreases, thus increasing colloid mobility. Results observed above the threshold concentration agree with a classical blocking mechanism typical of a high concentration regime. Results observed at lower colloid concentrations were not modeled with a classical blocking model and a depth- and time-dependent model with a second order kinetic law was necessary to correctly fit the experimental data in the entire range of colloid concentrations with a single set of parameters for each colloidal size. The colloid deposition mechanisms occuring at low concentrations were investigated through a pore structure analysis carried out with Mercury Intrusion Porosimetry and image analysis. The determined pore size distribution permitted estimation of the maximal retention capacity of the natural sand as well as some low flow zones. Altogether, these results stress the key role of the pore space geometry of the sand in controlling silica colloids deposition under hydro-geochemical conditions typical of sandy aquifers. Our results also showed originally that colloid

  12. Geostatistics as a basis to the CMLS pesticide simulation model with validation in soil columns Geoestatística como suporte ao modelo de simulação de agrotóxico CMLS com validação em colunas de solos

    Directory of Open Access Journals (Sweden)

    Gilberto Nicolella

    2005-01-01

    Full Text Available The use of simulation models is probably the most efficient means for predicting the behavior of pesticides in the soil-plant-water system. The CMLS (Chemical Movement in Layered Soils simulation model for predicting the fate of pesticides was used for studying the behavior of tebuthiuron, a herbicide used in sugar cane crops, from a sampling grid with 111 sampling points 200 m apart from one another and encompassing three types of soil: Ustic Quartzipsamment, Rhodic Hapludox and Typic Hapludox, all with medium and clay textures. The 373 points assessed by the simulator, generated from samples coming from the original grid and through the geostatistical methods of variography and ordinary kriging, returned the depth values reached by the herbicide after six years of simulation (1989-1995. For the Ustic Quartzipsamment, tebuthiuron, in four simulated points, returned depth values above 43 m and a maximum 50 m, with a certain amount of the product still remaining in the soil that was close to 10% of the original 1.1 kg ha-1 applied. Results from the column assay used for validating the model showed that the model overestimated the depth reached by the herbicide in 6.6% as compared to the column value for the Ustic Quartzipsamment. The depth was underestimated in 4.5% and 20% for the Typic Hapludox and the Rhodic Hapludox, respectively. These data support the adequacy of the model for assessing the fate of tebuthiuron in both Ustic Quartzipsamment and Typic Hapludox.O uso de modelos de simulação é provavelmente a maneira mais eficiente para predizer o comportamento de agrotóxicos no sistema solo/água/planta. O modelo de simulação de destino de agrotóxicos CMLS (Chemical Movement in Layered Soils, foi usado para estudar o comportamento do herbicida tebuthiuron, utilizado na cultura de cana-de-açúcar, a partir de uma grade de amostragem composta de 111 pontos amostrais, equi-espaçados de 200 m e englobando três tipos de solo: Neossolo

  13. Sample Disturbance in Resonant Column Test Measurement of Small-Strain Shear-Wave Velocity

    Science.gov (United States)

    Chiara, Nicola; Stokoe, K. H.

    The accurate assessment of dynamic soil properties is a crucial step in the solution process of geotechnical earthquake engineering problems. The resonant column test is one of the ordinary procedures for dynamic characterization of soil. In this paper, the impact of sample disturbance on the resonant column test measurement of small-strain S-wave velocity is examined. Sample disturbance is shown to be a function of the ratio of the laboratory to field S-wave velocities: Vs, lab/Vs,field. The influence of four parameters - soil stiffness, soil plasticity index, in-situ sample depth and in-situ effective mean confining pressure - on sample disturbance is investigated both qualitatively and quantitatively. The relative importance of each parameter in predicting the small-strain field S-wave velocity from the resonant column test values is illustrated and predictive equations are presented.

  14. DEVELOPMENT AND APPLICATION OF IMMUNOAFFINITY COLUMN CHROMATOGRAPHY AS A CLEANUP METHOD FOR THE DETERMINATION OF ATRAZINE IN COMPLEX ENVIRONMENTAL SAMPLE MEDIA

    Science.gov (United States)

    A rabbit antibody immunoaffinity (IA) column procedure was evaluated as a cleanup method for the determination of atrazine in soil, sediment, and food. Four IA columns were prepared by immobilizing a polyclonal rabbit anti-atrazine antibody solution to HiTrap Sepharose columns. A...

  15. 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.

  16. Mass Transport within Soils

    Energy Technology Data Exchange (ETDEWEB)

    McKone, Thomas E.

    2009-03-01

    zone with three major horizons, the saturated zone can be further divided into other zones based on hydraulic and geologic conditions. Wetland soils are a special and important class in which near-saturation conditions exist most of the time. When a contaminant is added to or formed in a soil column, there are several mechanisms by which it can be dispersed, transported out of the soil column to other parts of the environment, destroyed, or transformed into some other species. Thus, to evaluate or manage any contaminant introduced to the soil column, one must determine whether and how that substance will (1) remain or accumulate within the soil column, (2) be transported by dispersion or advection within the soil column, (3) be physically, chemically, or biologically transformed within the soil (i.e., by hydrolysis, oxidation, etc.), or (4) be transported out of the soil column to another part of the environment through a cross-media transfer (i.e., volatilization, runoff, ground water infiltration, etc.). These competing processes impact the fate of physical, chemical, or biological contaminants found in soils. In order to capture these mechanisms in mass transfer models, we must develop mass-transfer coefficients (MTCs) specific to soil layers. That is the goal of this chapter. The reader is referred to other chapters in this Handbook that address related transport processes, namely Chapter 13 on bioturbation, Chapter 15 on transport in near-surface geological formations, and Chapter 17 on soil resuspention. This chapter addresses the following issues: the nature of soil pollution, composition of soil, transport processes and transport parameters in soil, transformation processes in soil, mass-balance models, and MTCs in soils. We show that to address vertical heterogeneity in soils in is necessary to define a characteristic scaling depth and use this to establish process-based expressions for soil MTCs. The scaling depth in soil and the corresponding MTCs depend

  17. Simulação do transporte e da sorção de imazaquin em colunas de solo Simulation of imazaquin transport and sorption in soil columns

    Directory of Open Access Journals (Sweden)

    Robson Rolland Monticelli Barizon

    2006-08-01

    da curva, e apresentaram bom ajuste ao modelo bicontínuo, evidenciando que ocorreu não-equilíbrio no processo de sorção. A comparação dos dois métodos empregados mostrou que o coeficiente de sorção determinado no método "batch" foi maior. Tal resultado evidencia que a sorção, durante o processo de lixiviação, pode ser superestimada por métodos que consideram a sorção sob condições de equilíbrio químico.This experiment aimed at the evaluation of imazaquin sorption and transport in soils with different chemical, physical and mineralogical characteristics using batch and miscible-displacement techniques. The experiment was carried out with Neossolo Quartzarênico (RQ, Latossolo Vermelho-Amarelo (LVA and Latossolo Vermelho distroférrico (LVdf soils which were air-dried, passed through a 2 mm sieve and followed by chemical, physical and mineralogical characterization. A CaCl2 solution was applied in the miscible displacement experiment for the establishment of a Cl- elution curve that was used as tracer. The curves were adjusted to a model based on the convection-dispersion equation for ideal transport. Then a 14C-imazaquin solution was applied and the elution curves for this molecule obtained. The curve was adjusted to a bicontinuum model that considers non-equilibrium during the transport. In order to obtain the isotherms adjusted by Freundlich equation in the sorption experiment through the batch method, a radiolabel imazaquin solution was used with concentrations varying from 0.67 to 10.72 mmol L-1. The leaching was high for all soils and highest for the RQ soil. The Cl- elution curves were symmetric for all soils and adjusted well to the model that considers the ideal transport, showing that there was non-equilibrium related to the transport. The imazaquin elution curves were asymmetric with extension of the posterior part of the curve and well adjusted to the bicontinuum model, evidencing the occurrence of non-equilibrium in the sorption

  18. Renforcement de fondations superficielles par soil mixing : Analyses par modélisation physique et numérique

    OpenAIRE

    Dhaybi, Mathieu

    2015-01-01

    The reinforcement of shallow foundations by soil mixing consists on mixing the soil beneath with a hydraulic binder in order to obtain columns with mixed modulus. These columns, which have mechanical properties bounded between those of concrete and those of soil, can improve the soil bearing capacity and reduce excessive settlements as well. This research work is a phenomenological and quantitative study of the behavior of shallow foundations reinforced by soil mixing columns. It leads to ana...

  19. Transport of silver nanoparticles (AgNPs) in soil.

    Science.gov (United States)

    Sagee, Omer; Dror, Ishai; Berkowitz, Brian

    2012-07-01

    The effect of soil properties on the transport of silver nanoparticles (AgNPs) was studied in a set of laboratory column experiments, using different combinations of size fractions of a Mediterranean sandy clay soil. The AgNPs with average size of ~30nm yielded a stable suspension in water with zeta potential of -39mV. Early breakthrough of AgNPs in soil was observed in column transport experiments. AgNPs were found to have high mobility in soil with outlet relative concentrations ranging from 30% to 70%, depending on experimental conditions. AgNP mobility through the column decreased when the fraction of smaller soil aggregates was larger. The early breakthrough pattern was not observed for AgNPs in pure quartz columns nor for bromide tracer in soil columns, suggesting that early breakthrough is related to the nature of AgNP transport in natural soils. Micro-CT and image analysis used to investigate structural features of the soil, suggest that soil aggregate size strongly affects AgNP transport in natural soil. The retention of AgNPs in the soil column was reduced when humic acid was added to the leaching solution, while a lower flow rate (Darcy velocity of 0.17cm/min versus 0.66cm/min) resulted in higher retention of AgNPs in the soil. When soil residual chloride was exchanged by nitrate prior to column experiments, significantly improved mobility of AgNPs was observed in the soil column. These findings point to the importance of AgNP-soil chemical interactions as a retention mechanism, and demonstrate the need to employ natural soils rather than glass beads or quartz in representative experimental investigations.

  20. Effect of peat characteristics on P, N and DOC mobilization from re-wetted peat soils - a laboratory column study for the impacts of restoration on forestry-drained peatlands

    Science.gov (United States)

    Koskinen, Markku; Kaila, Annu; Asam, Zaki; Uusitalo, Risto; Smolander, Aino; Kiikkilä, Oili; Sarkkola, Sakari; Kitunen, Veikko; Fritze, Hannu; Nousiainen, Hannu; Tervahauta, Arja; Xiao, Liwen; Nieminen, Mika

    2016-04-01

    Peatlands are an integral part of the hydrological cycle in the boreal and temperate zones, providing ecosystem services such as water filtering. From the mid to late 1900's, over 15 ha of peatlands and wetlands were drained for forestry in the temperate and boreal zones, causing deterioration of biodiversity and loss of ecosystem services. They are now being restored in order to reverse this development. Restoration of pealands has been found to cause leaching of DOC and nutrients after water level rise and expansion of reducing conditions in the peat. A molar ratio between redox-sensitive Fe and P in the peat of < 10 has been previously suggested as a limit value indicating risk of high P export. The ratio, however, does not predict the level of P release well when the value is < 10. It has also been suggested that redox-sensitive Fe is involved in the export of DOC via consumption of protons during reduction reactions of Fe, which reduces the soil positive charge and makes the DOC molecules more electronegative, which makes them repeal each other. An incubation experiment was conducted to study factors affecting P, N and DOC release from inundated peat from forestry-drained peatlands of several fertility classes. It was discovered that in addition to Fe, a high ratio of Al to P in the peat reduces P export under reducing conditions. High peat Fe content was also found to predict high DOC export, suggesting that minerotrophic sites are susceptible to post-restoration DOC leaching due to the Fe in their peat. Microbial biomass and mineralization potential of the peat were not found to be important for the export of DOC or P. High NO3 content in the peat predicted high export of NH4 under reducing conditions.

  1. Anaerobic N mineralization in paddy soils in relation to inundation management, physicochemical soil fractions, mineralogy and soil properties

    Science.gov (United States)

    Sleutel, Steven; Kader, Mohammed Abdul; Ara Begum, Shamim; De Neve, Stefaan

    2013-04-01

    Anaerobic N mineralization measured from (saturated) repacked soil cores from 25 paddy fields in Bangladesh and was previously found to negatively related to soil N content on a relative basis. This suggests that other factors like soil organic matter (SOM) quality or abiotic factors instead control the anaerobic N mineralization process. We therefore assessed different physical and chemical fractions of SOM, management factors and various soil properties as predictors for the net anaerobic N mineralization. 1° First, we assessed routinely analyzed soil parameters (soil N and soil organic carbon, texture, pH, oxalate- and pyrophosphate-extractable Fe, Al, and Mn, fixed-NH4 content). We found no significant influences of neither soil mineralogy nor the annual length of inundation on soil N mineralization. The anaerobic N mineralization correlated positively with Na-pyrophosphate-extractable Fe and negatively with pH (both at Pisolate an oxidation-resistant OM fraction, followed by extraction of mineral bound OM with 10%HF thereby isolating the HF-resistant OM. None of the physicochemical SOM fractions were found useful predictors anaerobic N mineralization. The linkage between these chemical soil N fractions and N supplying processes actually occurring in the soil thus appears to be weak. Regardless, we hypothesize that variation in strength of N-mineral and N-OM linkages is likely to explain variation in bio-availability of organic N and proneness to mineralization. Yet, in order to separate kinetically different soil N fractions we then postulated that an alternative approach would be required, which instead isolates soil N fractions on the basis of bonding strength. In this respect bonding strength should be seen as opposite of proneness to dissolution of released N into water, the habitat of soil microorganisms mediating soil N mineralization. We hypothesize that soil N extracted by water at increasing temperatures would reflect such N fractions with increasing

  2. Stiff Columns as Liquefaction Mitigation Measure for Retrofit of Existing Buildings

    Directory of Open Access Journals (Sweden)

    Zaheer Ahmed Almani

    2012-10-01

    Full Text Available In this paper, ground reinforcement with jet grouted columns under shallow foundations of existing buildings was analysed using numerical modelling. This study is related with ground reinforcement by installing stiff jet grouted columns around the shallow foundations of existing building when the foundation soil is liquefied during an earthquake. The isolated shallow square footing pad supporting a typical simple frame structure was constructed on the reinforced ground with stiff jet grouted column rows at the shallow depth from the ground surface. This soil-structure system was modelled and analyzed as plane-strain using the FLAC (Fast Lagrangian Analysis of Continua 2D dynamic modelling and analysis software. The results showed that liquefaction-induced large settlement of shallow foundation of existing building can be reduced to tolerable limits by applying ground reinforcement with continuous rows vertical jet grouted columns adjacent to footing pad.

  3. Columns

    Institute of Scientific and Technical Information of China (English)

    于晓悠; 丁燕燕; 韩多妮; Ray; Carrie; 未冉

    2010-01-01

    <正>New York Whitney艺术双年展今年第75届纽约Whitney双年展不设题目,但以"2010"指示策展方向,继续以发掘年轻艺术家、展示创作实验为目标。参展的55位艺术家,最年轻的是23岁摄影师Tam Tran,最老资历的是75岁的概念艺术家Lorraine O’Grady。这届的另一先创性,是每位艺术家只限一件或一个系列的作品,避免了去届双年展的"小型个人回顾展"现象,而五层楼的展场各有特色,如录像及短片将独立于三楼展出,而美术馆馆藏则移师五楼。这届双年展由著名的意大利策展人Francesco Bonami联同助手Gary Carrion-Murayarn共同制作,两位策展人说明,双年展的重要性是预示未来,创新及前瞻性依然是取决原则。

  4. Columns

    Institute of Scientific and Technical Information of China (English)

    Carrie Tsang; 丁燕燕; 韩多妮; RAY

    2009-01-01

    <正>Paris承诺的展现33岁的墨西哥艺术家Mario Garcia Torres是近年国际艺坛炙手可热的新星,他以录象、摄影、幻灯及装置为创作形式,透过个人视点及独特演绎手法来重新思考历史。他是一个思考型艺术家,同时又是一个淘气的大孩子,作品往往反映了他的双重性格——嬉戏中带有深沉的历史感。这次是GarciaTorres首次在法国的国家博物馆举行展览,整合出版了他过往两年间在

  5. 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.

  6. Effect of soil property on evaporation from bare soils

    Science.gov (United States)

    Zhang, Chenming; Li, Ling; Lockington, David

    2015-04-01

    Quantifying the actual evaporation rate from bare soils remains a challenging task as it not only associates with the atmospheric demand and liquid water saturation on the soil surface, but also the properties of the soils (e.g., porosity, pore size distribution). A physically based analytical model was developed to describe the surface resistance varying with the liquid water saturation near the soil surface. This model considers the soil pore size distribution, hydraulic connection between the main water cluster and capillary water in the soil surface when the soil surface is wet and the thickness of the dry soil layer when the soil surface is dry. The surface resistance model was then integrated to a numerical model based on water balance, heat balance and surface energy balance equations. The integrated model was validated by simulating water and heat transport processes during six soil column drying experiments. The analysis indicates that the when soil surface is wet, the consideration of pore size distribution in the surface resistance model offers better estimation of transient evaporation among different soil types than the estimations given by empirically based surface resistance models. Under fixed atmospheric boundary condition and liquid water saturation, fine sand has greater evaporation rate than coarse sand as stronger capillary force devlivers more water from the main water cluster. When the soil surface becomes dry, the impact of soil property to evaporation becomes trivial as the thickness of the dry soil layer turns to be the key factor to determine the evaporation rate.

  7. Enhanced phytoremediation in the vadose zone: Modeling and column studies

    Science.gov (United States)

    Sung, K.; Chang, Y.; Corapcioglu, M.; Cho, C.

    2002-05-01

    Phytoremediation is a plant-based technique with potential for enhancing the remediation of vadoese zone soils contaminated by pollutants. The use of deep-rooted plants is an alternative to conventional methodologies. However, when the phytoremediation is applied to the vadose zone, it might have some restrictions since it uses solely naturally driven energy and mechanisms in addition to the complesxity of the vadose zone. As a more innovative technique than conventional phytoremediation methods, air injected phytoremediation technique is introduced to enhance the remediation efficiency or to apply at the former soil vapor extraction or bio venting sites. Effects of air injection, vegetation treatment, and air injection with vegetation treatments on the removal of hydrocarbon were investigated by column studies to simulate the field situation. Both the removal efficiency and the microbial activity were highest in air-injected and vegetated column soils. It was suggested that increased microorganisms activity stimulated by plant root exudates enhanced biodegradation of hydrocarbon compounds. Air injection provided sufficient opportunity for promoting the microbial activity at depths where the conditions are anaerobic. Air injection can enhance the physicochemical properties of the medium and contaminant and increase the bioavailability i.e., the plant and microbial accessibility to the contaminant. A mathematical model that can be applied to phytoremediation, especially to air injected phytoremediation, for simulating the fate and the transport of a diesel contaminant in the vadose zone is developed. The approach includes a two-phase model of water flow in vegetated and unplanted vadose zone soil. A time-specific root distribution model and a microbial growth model in the rhizosphere of vegetated soil were combined with an unsaturated soil water flow equation as well as with a contaminant transport equation. The proposed model showed a satisfactory representation of

  8. Unlocking the Physiochemical Controls on Organic Carbon Dynamics from the Soil Pore- to Core-Scale

    Science.gov (United States)

    Smith, A. P.; Tfaily, M. M.; Bond-Lamberty, B. P.; Todd-Brown, K. E.; Bailey, V. L.

    2015-12-01

    The physical organization of soil includes pore networks of varying size and connectivity. These networks control microbial access to soil organic carbon (C) by spatially separating microorganisms and C by both distance and size exclusion. The extent to which this spatially isolated C is vulnerable to microbial transformation under hydrologically dynamic conditions is unknown, and limits our ability to predict the source and sink capacity of soils. We investigated the effects of shifting hydrologic connectivity and soil structure on greenhouse gas C emissions from surface soils collected from the Disney Wilderness Preserve (Florida, USA). We subjected intact soil cores and re-packed homogenized soil cores to simulated groundwater rise or precipitation, monitoring their CO2 and CH4 emissions over 24 hours. Soil pore water was then extracted from each core using different suctions to sample water retained by pore throats of different sizes and then characterized by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Greater respiration rates were observed from homogenized cores compared to intact cores, and from soils wet from below, in which the wetting front is driven by capillary forces, filling fine pores first. This suggests that C located in fine pores may turn over via diffusion processes that lead to the colocation of this C with other resources and microorganisms. Both the complexity and concentration of soluble-C increased with decreasing pore size domains. Pore water extracted from homogenized cores had greater C concentrations than from intact cores, with the greatest concentrations in pore waters sampled from very fine pores, highlighting the importance of soil structure in physically protecting C. These results suggest that the spatial separation of decomposers from C is a key mechanism stabilizing C in these soils. Further research is ongoing to accurately represent this protection mechanism, and the conditions under which it breaks

  9. Imidacloprid transport and sorption nonequilibrium in single and multilayered columns of Immokalee fine sand.

    Science.gov (United States)

    Leiva, Jorge A; Nkedi-Kizza, Peter; Morgan, Kelly T; Kadyampakeni, Davie M

    2017-01-01

    Imidacloprid (IMD) is a neonicotinoid pesticide soil-drenched to many crops to control piercing-sucking insects such as the Asian citrus psyllid (ACP). Neonicotinoids are persistent in the environment and transport analyses are helpful estimate leaching potential from soils that could result in groundwater pollution. The objective of this study was to analyze IMD breakthrough under saturated water flow in soil columns packed with three horizons (A, E, Bh) of Immokalee Fine Sand (IFS). Also, we used the dimensionless form of the convective-dispersive model (CD-Model) to compare the optimized transport parameters from each column experiment (retardation factor, R; fraction of instantaneous-to-total retardation, β; and mass transfer coefficient, ω) with the parameters obtained from sorption batch equilibria and sorption kinetics. The tracer (Cl-) breakthrough curves (BTCs) were symmetrical and properly described by the CD-Model. IMD BTCs from A, Bh, and multilayered [A+E+Bh] soil columns showed steep fronts and tailing that were well described by the one-site nonequilibrium (OSNE) model, which was an evidence of non-ideal transport due to IMD mass transfer into the soil organic matter. In general, IMD was weakly-sorbed in the A and Bh horizons (R values of 3.72 ± 0.04 and 3.08 ± 0.07, respectively), and almost no retardation was observed in the E horizon (R = 1.20 ± 0.02) due to its low organic matter content (0.3%). Using the HYDRUS-1D package, optimized parameters (R, β, ω) from the individual columns successfully simulated IMD transport in a multilayered column mimicking an IFS soil profile. These column studies and corresponding simulations agreed with previous findings from batch sorption equilibria and kinetics experiments, where IMD showed one-site kinetic mass transfer between soil surfaces and soil solution. Ideally, sandy soils should be maintained unsaturated by crop irrigation systems and rainfall monitoring during and after soil-drench application

  10. An automated microinfiltrometer to measure small-scale soil water infiltration properties

    Directory of Open Access Journals (Sweden)

    Gordon Dennis C.

    2014-09-01

    Full Text Available We developed an automated miniature constant-head tension infiltrometer that measures very small infiltration rates at millimetre resolution with minimal demands on the operator. The infiltrometer is made of 2.9 mm internal radius glass tube, with an integrated bubbling tower to maintain constant negative head and a porous mesh tip to avoid air-entry. In the bubbling tower, bubble formation and release changes the electrical resistance between two electrodes at the air-inlet. Tests were conducted on repacked sieved sands, sandy loam soil and clay loam soil, packed to a soil bulk density ρd of 1200 kg m-3 or 1400 kg m-3 and tested either air-dried or at a water potential ψ of -50 kPa. The change in water volume in the infiltrometer had a linear relationship with the number of bubbles, allowing bubble rate to be converted to infiltration rate. Sorptivity measured with the infiltrometer was similar between replicates and showed expected differences from soil texture and ρd, varying from 0.15 ± 0.01 (s.e. mm s-1/2 for 1400 kg m-3 clay loam at ψ = -50 kPa to 0.65 ± 0.06 mm s-1/2 for 1200 kg m-3 air dry sandy loam soil. An array of infiltrometers is currently being developed so many measurements can be taken simultaneously.

  11. Improvement of Marine Clay Performance Using Geo-Textile Encased Stone Column

    Directory of Open Access Journals (Sweden)

    S. Siva Gowri Prasad

    2015-10-01

    Full Text Available The use of stone columns is a popular ground reinforcing technique for flexible structures like raft foundations, oil storage tanks, embankments etc. The stone column technique is a cost effective method of improving the strength parameters like bearing capacity and reduce the settlements. When stone columns in soft soil are loaded, it undergoes excessive bulging due to low lateral confinement. To avoid this excessive bulging, stone column is encased with geotextile. In the present study tests were performed with and without encasement of geotextile. Stone column is encased with geotextile with different lengths of encasement like L/4, L/2, 3L/4 & L. The tests indicate that the bearing capacity increases with increase of encasement length.

  12. Modeling of column apparatus processes

    CERN Document Server

    Boyadjiev, Christo; Boyadjiev, Boyan; Popova-Krumova, Petya

    2016-01-01

    This book presents a new approach for the modeling of chemical and interphase mass transfer processes in industrial column apparatuses, using convection-diffusion and average-concentration models. The convection-diffusion type models are used for a qualitative analysis of the processes and to assess the main, small and slight physical effects, and then reject the slight effects. As a result, the process mechanism can be identified. It also introduces average concentration models for quantitative analysis, which use the average values of the velocity and concentration over the cross-sectional area of the column. The new models are used to analyze different processes (simple and complex chemical reactions, absorption, adsorption and catalytic reactions), and make it possible to model the processes of gas purification with sulfur dioxide, which form the basis of several patents.

  13. Comparison of drug substance impurity profiles generated with extended length columns during packed-column SFC.

    Science.gov (United States)

    Roston, D A; Ahmed, S; Williams, D; Catalano, T

    2001-10-01

    The current study assesses the effect of extending column length during gradient packed column sub/supercritical fluid chromatography (PCSFC) experiments on the detection of known and unknown impurities in a drug substance sample. Quantitative drug substance impurity profiles were generated and compared using multiple column PCSFC and HPLC conditions. Also, chromatographic figures of merit were estimated and compared for components of a standard mixture during PCSFC experiments, which used one column, four columns, and six columns in series.

  14. Beam Studies with Electron Columns

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, V.; Valishev, A.; Kuznetsov, G.; /Fermilab; Kamerdzhiev, V.; /Julich, Forschungszentrum; Romanov, A.; /Novosibirsk, IYF

    2009-04-01

    We report preliminary results of experimental studies of 'electron columns' in the Tevatron and in a specialized test setup. In the Tevatron, a beam of 150 GeV protons ionizes residual gas and ionization electrons are stored in an electrostatic trap immersed into strong longitudinal magnetic field. Shifts of proton betatron frequencies are observed. In the test setup, we observe effects pointing to accumulation and escape of ionization electrons.

  15. Sulfamethazine transport in agroforestry and cropland soils

    Science.gov (United States)

    Knowledge of veterinary antibiotic transport and persistence is critical to understanding environmental risks associated with these potential contaminants. To understand mobility of sulfamethazine (SMZ) and sorption processes involved during SMZ transport in soil, column leaching experiments were p...

  16. Water Column Methylation in Estuaries

    Science.gov (United States)

    Schartup, A. T.; Calder, R.; Soerensen, A. L.; Mason, R. P.; Balcom, P. H.; Sunderland, E. M.

    2014-12-01

    Methylmercury (MeHg) is a neurotoxin that bioaccumulates in aquatic food webs and affects humans and wildlife through fish consumption. Many studies have measured active methylation/demethylation in ocean margin sediments but few have reported similar rates for the marine water column. This presentation will review available evidence for water column methylation in estuaries, including new experimental measurements of methylation/demethylation rates from a deep subarctic fjord in Labrador Canada collected in Spring and Fall of 2012-2013. We used these and other data to construct a mass budget for MeHg in the estuary and show that water column methylation (with rates ranging from 1.5 to 2.8 % day-1), is the largest contributor, followed by inputs from rivers (4.9 mol year-1), to the in situ pool of MeHg available for uptake by biota. By contrast, the sediment in this system is a net sink for MeHg (-1.5 mol year-1). We discuss the relationship between observed MeHg and other ancillary environmental factors (organic carbon, sulfur and nutrients) as well as implications for the response time of fish to future changes in mercury inputs.

  17. Study on the downward movement of carbofuran in two Malaysian soils.

    Science.gov (United States)

    Farahani, G H N; Sahid, Ismail Bin; Zakaria, Zuriati; Kuntom, Aini; Omar, Dzolkifli

    2008-09-01

    The downward movement of carbofuran in two Malaysian soil types was studied using soil columns. The columns were filled with disturbed and undisturbed soils of either the Bagan Datoh soil (clay) or the Labu soil (sandy clay). The average total percentage of carbofuran in the leachate of the undisturbed Labu soil after 14 days of watering (80.8%) was approximately similar to that of the total amount from the disturbed soil (81.4%). However, carbofuran leaching was observed in the disturbed soil after the fourth day of watering whereas for the undisturbed soil, leaching occurred after the first watering. A similar trend was observed in the Bagan Datoh soil where the residue of carbofuran was detected after the first day of watering in the undisturbed soil column but only at the eighth day of watering in the disturbed soil column. The total percentage carbofuran in the leachate of disturbed and undisturbed soil columns from Bagan Datoh after 14 days of watering was 3.6% and 41.7%, respectively. The study showed that less leaching occurred in soil columns with high organic content such as the Bagan Datoh soil and especially so in disturbed soils where the organic matter was homogeneously mixed in all layers.

  18. Quantitative Effect of Soil Texture Composition on Retardation Factor of K+ Transport

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    With six packed columns composed of <1μm and 5μm~0.25 mm fractions from an Eum-Orthic Anthrosol (Columns 1~6) and one column of the Eum-Orthic Anthrosol (Column 7), K+ transport experiments under the condition of saturated steady water flow were conducted to qualify the effects of soil texture composition on the retardation factor (R) of K+ transport. The results showed that the retardation factor of K+ transport in the tested soil columns greatly increased with increasing clay contents. In an attempt to use pedo-transfer function (PTF) approach in the solute transport study, a preliminary PTF was established through the six packed columns (Columns 1~6) with soil basic data including soil bulk density, volumetric water content and clay content to predict the retardation factor, and proved valid by the satisfactory prediction of R in Column 7.

  19. 大型蛋白质色谱柱及凝胶介质的综述%The Development of Gel Media and Columns for Large-Scale Chromatography of Proteins, a Historical Review

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The first dedicated protein chromatography media were introduced during the 1950s and 1960s. There was an early awareness of the possibility of using these for production applications within the biopharmaceutical industry. However, the crucial limitation was the fact that those media that were most compatible with proteins lent themselves less favourably to scaling-up. The problems were primarily physical. Thus the fibrous cellulose media showed bed cracking tendencies and the bead shaped polyacrylamide, dextran, and agarose gel media, then available,were too soft to stand the hydrodynamic forces acting in large columns, leading to bed compaction and increased pressure drop. At the time, the best solution to the latter problem, after a number of intermediary solutions were tried, was the introduction of the stacked column concept in which several short column segments were connected by small bore tubing, thus reducing the force acting on the particles in each bed compartment. However, the ultimate remedy, the introduction of chromatographic matrices that combine the desired features of adequate rigidity,macroporosity, biocompatibility, chemical stability (for CIP and SIP) and derivatizability, did not occur until the middle of the 1980s when adequately cross-linked agarose gel media such as Sepharose(R) Fast Flow were made available. The paper also recognizes the many attempts made during the past 50 years to develop continous chromatography columns. Most of the designs are based on an annular bed or on an array of annularly arranged parallel columns continuously fed with samples in a cyclic manner. The introduction of media and columns for expanded bed adsorption followed a demand for fewer purification steps and shorter process times. In recent years, columns have been introduced that allow packing and repacking without needing to open the column. The review provides an historical account of the developments that have led to the present state-of-the-art both

  20. Nitrogen removal from urban stormwater runoff through layered bioretention columns.

    Science.gov (United States)

    Hsieh, Chi-hsu; Davis, Allen P; Needelman, Brian A

    2007-11-01

    Bioretention is a low-impact technology used for the treatment of stormwater runoff in developed areas. The fates of mineral nitrogen compounds in two bioretention columns (RP1 and RP2) with different media-layering characteristics were investigated under multiple loadings of simulated urban runoff. The immediate capture of nitrogen was evaluated, with nitrogen transformation reactions that occurred during the drying periods between rainfall events. A greater proportion of ammonium was removed from runoff in RP2 (68 +/- 16%), which had a high permeability layer over a lower permeability layer, than in RP1 (12 +/- 6%), which had the inverse configuration. Both column systems demonstrated nitrate export (9 +/- 32% and 54 +/- 22% greater than input for RP1 and RP2, respectively), attributed to washout of nitrate resulting from nitrification processes between runoff loading events. Bioretention media with a less permeable bottom soil layer could form an anoxic/anaerobic zone for promoting nitrification/denitrification processes.

  1. ANALYSIS ON EARTHQUAKE RESPONSE OF COLUMN-SUPPORTED CONCRETE COAL BUNKER STRUCTURE BASED ON SOIL-STRUCTURE INTERACTION%基于土-结构相互作用的柱承式混凝土煤仓结构地震响应分析∗

    Institute of Scientific and Technical Information of China (English)

    薛志成; 姜博文; 张林; 裴强

    2016-01-01

    The modal analysis of a column-supported concrete bunker structure was carried out,the characteristics of the mode shapes and frequencies were obtained. At the same time, based on the soil-structure interaction,the time history analysis of earthquake response of the concrete bunker structure was also done; through the input of three kinds of earthquake waves (El Centro, Taft wave and artificial wave),a time history of the displacement of coal bunker structure node and its maximum displacement were got,and the weak parts of the structure were determined, which provided a reference to the seismic design and identification of such sort of coal bunker structure.%对柱承式混凝土煤仓结构进行模态分析,得到其振型和频率的特点。同时,基于土-结构相互作用,进行柱承式混凝土煤仓结构的地震反应时程分析,通过输入3种地震波( El Centro波、Taft波和人工波),分析得到不同工况下煤仓结构节点的位移时程和最大位移值,确定出结构的薄弱部位,为柱承式混凝土煤仓结构的抗震设计和鉴定提供参考。

  2. Leaching of Salmonella Senftenberg and Cryptosporidium Parvum in Intact Clay Columns

    Science.gov (United States)

    Bech, T. B.; Forslund, A.; Dalsgaard, A.; Jacobsen, O.; Jacobsen, C. S.

    2008-12-01

    Manure application on land has been associated with both environmental and public health problems, even when management is within the current guidelines. Outbreaks of infection have been associated with water or food, including processed fruits and vegetables, contaminated with animal manure. A wide range of pathogenic microorganisms can be found in animal waste, including bacteria, protozoan, and viruses. When animal waste is disposed on agricultural land different factors will influence the risk for contaminating the groundwater. 1) Animal waste application method, rate, volume and frequency will have an effect on contamination. 2) Survival of the pathogens in the soil will e.g. depend on soil water content, temperature and pH. Salmonella species can survive up to 332 days and Cryptosporidium species can remain viable for several years in the soil environment. In the present study we compared the transport between the pathogenic bacteria S. senftenberg and the pathogenic protozoan C. parvum in intact clay columns. Furthermore, we compared the effect from surface and sub-surface manure application on the transport potential. 15 intact clay columns were placed in an outdoor multi-column lysimeter for 36 days. Manure inoculated with S. senftenberg, C. parvum and chloride was added to the soil surface or injected 8 cm into the columns. Drainage water was collected from the soil columns and DNA was extracted to quantify S. senftenberg and C. parvum by quantitative PCR. In addition S. senftenberg was enumerated by plate counting. Acid yellow was applied to selected columns to visualize the pathway down through the soil column. The highest concentration of S. senftenberg was in the first drainage sample ranging from 100-10000 CFU/ml. Breakthrough curves for chloride and S. senftenberg indicates the importance of preferential flow as well as a faster transport for the bacteria compared to chloride. C. parvum is retained to a higher degree in the soil but is still found

  3. Salt—Water Dynamics in Soils:V.Salt Balance in Soil Profiles

    Institute of Scientific and Technical Information of China (English)

    YOUWEN-RUI; MENGFAN-HUA

    1995-01-01

    Salt balance in simulated soil coulumns was calculated on the basis of a large amount of long term observation data.The results showed that under the climate conditions of semi-arid region of the Huang-Huai-Hai Plain,the soils in the columns were under salt accumulation conditions when the groundwater depth was controlled at less than 2.0m,and under desalinization conditions when at larger than 2.5m.In the soil columns with clay soil and silty loam soil intercalated with a clay layer,the amount of salt accumulated was far less than that in the soil column with silty loam soil throughout the whole profile.Under no irriagtion conditions crop planting may increase groundwater evaporation and hence salt accumulation in soil,making the soil columns under desalinization be under salt accumulation conditions.

  4. Mobility of Tylosin and Enteric Bacteria in Soil Columns

    Science.gov (United States)

    To maximize production, producers regularly use antibiotics as supplements in animal feed and water to increase weight gain and prevent diseases among their livestock, which may result in nonpoint source pollution of ground or surface waters. This study examined the leaching of the enteric bacteria ...

  5. Site soil column considerations in seismic hazard analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bernreuter, D.L.

    1978-12-01

    A theoretical approach is used to show the importance of differences in earthquake-generating mechanisms. Data from underground nuclear explosions show the importance of slight variations in travel path. The influence of the site is studied using two approaches. The first uses data recorded at the same site during a number of different earthquakes. The second fixes the earthquake, in this case the San Fernando earthquake, and examines all sites that are one-sigma sites to see if there is a common generic site type that significantly amplifies the ground motion. It is concluded that generally fixing the site does not reduce the variation of the data. At site-resonant frequencies, the spectral response is greater than envelope spectra of Regulatory Guide 1.60. Small near-field earthquakes have significantly greater high-frequency content than is cntained in Regulatory Guide 1.60. No generic site condition could be determined that consistently amplified the ground motion from the San Fernando earthquake.

  6. Elastic stability of non-uniform columns

    Science.gov (United States)

    Lee, S. Y.; Kuo, Y. H.

    1991-07-01

    A simple and efficient method is proposed to investigate the elastic stability of three different tapered columns subjected to uniformly distributed follower forces. The influences of the boundary conditions and taper ratio on critical buckling loads are investigated. The critical buckling loads of columns of rectangular cross section with constant depth and linearly varied width ( T1), constant width and linearly varied depth ( T2) and double taper ( T3) are investigated. Among the three different non-uniform columns considered, taper ratio has the greatest influence on the critical buckling load of column T3 and the lowest influence on that of column T1. The types of instability mechanisms for hinged-hinged and cantilever non-uniform columns are divergence and flutter respectively. However, for clamped-hinged and clamped-clamped non-uniform columns, the type of instability mechanism for column T1 is divergence, while that for columns T2 and T3 is divergence only when the taper ratio of the columns is greater than certain critical values and flutter for the rest value of taper ratio. When the type of instability mechanism changes from divergence to flutter, there is a finite jump for the critical buckling load. The influence of taper ratio on the elastic stability of cantilever column T3 is very sensitive for small values of the taper ratio and there also exist some discontinieties in the critical buckling loads of flutter instability. For a hinged-hinged non-uniform column ( T2 or T3) with a rotational spring at the left end of the column, when the taper ratio is less than the critical value the instability mechanism changes from divergence to flutter as the rotational spring constant is increased. For a clamped-elastically supported non-uniform column, when the taper ratio is greater than the critical value the instability mechanism changes from flutter to divergence as the translational spring constant is increased.

  7. Nitrogen, phosphorus, potassium, calcium and magnesium release from two compressed fertilizers: column experiments

    Directory of Open Access Journals (Sweden)

    M. J. Fernández-Sanjurjo

    2014-07-01

    Full Text Available We used soil columns to study nutrients release from two compressed NPK fertilizers. The columns were filled with soil material from the surface horizon of a granitic soil. Tablets of two slow-release NPK fertilizers (11-18-11 or 8-8-16 were placed into the soil, and then water was percolated through the columns in a saturated regime. Percolates were analyzed for N, P, K, Ca and Mg. These nutrients were also determined in soil and fertilizer tablets at the end of the trials. Nutrient concentrations were high in the first percolates, reaching a steady state when 1426 mm water have percolated, which is equivalent to approximately 1.5 years of rainfall in the geographic area. In the whole trial, both tablets lost more than 80% of their initial N, P and K contents. However, K, Ca and Mg were the most leached, whereas N and P were lost in leachates to a lesser extent. Nutrient release was slower from the tablet with composition 8-8-16 than from the 11-18-11 fertilizer. In view of that, the 8-8-16 tablet can be considered more adequate for crops with a nutrient demand sustained over time. At the end of the trial, the effects of these fertilizers on soil chemical parameters were still evident.

  8. Challenges in the Application of Fractional Derivative Models in Capturing Solute Transport in Porous Media: Darcy-Scale Fractional Dispersion and the Influence of Medium Properties

    Directory of Open Access Journals (Sweden)

    Yong Zhang

    2013-01-01

    Full Text Available Heterogeneous media consisting of segregated flow regions are fractional-order systems, where the regional-scale anomalous diffusion can be described by the fractional derivative model (FDM. The standard FDM, however, first, cannot characterize the Darcy-scale dispersion through repacked sand columns, and second, the link between medium properties and model parameters remains unknown. To fill these two knowledge gaps, this study applies a tempered fractional derivative model (TFDM to capture bromide transport through laboratory repacked sand. Column transport experiments are conducted first, where glass beads and silica sand with different diameters are repacked individually. Late-time tails are observed in the breakthrough curves (BTC of bromide even in relatively homogeneous glass beads. The TFDM can capture the observed subdiffusion, especially the late-time BTC with a transient declining rate. Results also show that both the size distribution of repacked sand and the magnitude of fluid velocity can affect subdiffusion. In particular, a wider sand size distribution or a smaller flow rate can enhance the subdiffusion, leading to a smaller time index and a higher truncation parameter in the TFDM. Therefore, the Darcy-scale dispersion follows the tempered stable law, and the model parameters might be related to the soil size and flow conditions.

  9. Produced fluids separation using a coalascer column

    Energy Technology Data Exchange (ETDEWEB)

    Renouf, G.; Soveran, D.; Soveran, L. [Saskatchewan Research Council, Saskatoon, SK (Canada)

    2005-07-01

    This paper reports the results of a laboratory study in which a coalescer column was used to successfully remove water from produced heavy oil emulsions. The coalescer column is a simple, inexpensive, and environmentally friendly technology that can improve basic sediment and water values after 4 hours of settling time by about 38 per cent. The laboratory study tested the use of the column, and the effects of column length, column packing size, temperature, flow rate, demulsifier concentration, and water addition. More than 100 tests were conducted and 24 pairs of tests compared the treating effects with and without the column. The use of the coalescer column in the treatment facility resulted in a a reduction of demulsifier concentration from 250 ppm to 70 ppm, translating to an annual cost savings of $320,000 to $1,100,000 per battery. Incorporating the coalescer column also allowed operators to reduce both temperatures and demulsifier concentrations. The column also promoted faster treating. Water droplets grew by as much as 34 per cent, suggesting that treating time could be faster by 21 to 80 per cent. It was concluded that the coalescer column was very successful at improving water removal from heavy oil battery emulsions. 22 refs., 9 tabs., 7 figs.

  10. Column flotation testing at Suncor Energy Inc.

    Energy Technology Data Exchange (ETDEWEB)

    Cleyle, P.; Lee, L. [Suncor Energy Inc. Oil Sands, Fort McMurray, AB (Canada)

    2006-07-01

    The operations at Suncor's primary extraction plant were reviewed with reference to the column flotation process and the history of column flotation testing at Suncor. Tertiary bitumen recovery processes were also reviewed. In March and August 2005, an in-plant pilot scale column flotation test was conducted at Suncor's Millennium Primary Extraction plant near Fort McMurray, Alberta. The purpose was to evaluate the feasibility of using column flotation for tertiary bitumen recovery from cyclone overflow. The test was performed in a 4 ft diameter by 25 ft high column to determine the effects of column feed flow rate, froth wash water supply, and froth depth. The feed ranged from 0.14 to 3.79 wt per cent bitumen. Feed flow rate ranged from 59 to 237 USGPM. The test results indicated that wash water reduced froth mineral content. Increasing the wash water did not make any difference in mineral rejection. Although bitumen upgrading improved when the test column was operated at a deeper froth depth, the mineral content was not reduced. Both mechanical cell and flotation column tailings samples were collected in the flotation column tests. The average tailings composition for the last cell in the tertiary mechanical bank was 0.22 per cent bitumen, 12.10 per cent mineral, and 87.66 per cent water. At an average test column feed rate of 158 USGPM, the average tailings composition was 0.23 per cent bitumen, 12.13 per cent mineral, and 87.62 per cent water. It was concluded that flotation columns are capable of producing a tailings product similar to that of the tertiary mechanical bank. Therefore, it is feasible to use flotation columns as an alternative to mechanical cells. In fact, since there are no rotating parts requiring off-line maintenance work, flotation columns may be a better alternative from a maintenance and operations perspective. tabs., figs.

  11. Oscillating water column structural model

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, Guild [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jepsen, Richard Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gordon, Margaret Ellen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    An oscillating water column (OWC) wave energy converter is a structure with an opening to the ocean below the free surface, i.e. a structure with a moonpool. Two structural models for a non-axisymmetric terminator design OWC, the Backward Bent Duct Buoy (BBDB) are discussed in this report. The results of this structural model design study are intended to inform experiments and modeling underway in support of the U.S. Department of Energy (DOE) initiated Reference Model Project (RMP). A detailed design developed by Re Vision Consulting used stiffeners and girders to stabilize the structure against the hydrostatic loads experienced by a BBDB device. Additional support plates were added to this structure to account for loads arising from the mooring line attachment points. A simplified structure was designed in a modular fashion. This simplified design allows easy alterations to the buoyancy chambers and uncomplicated analysis of resulting changes in buoyancy.

  12. Laboratory column studies for evaluating a barrier system for providing oxygen and substrate for TCE biodegradation.

    Science.gov (United States)

    Kao, C M; Chen, S C; Su, M C

    2001-08-01

    The industrial solvent trichloroethylene (TCE) is among the most ubiquitous chlorinated compounds found in groundwater contamination. The objective of this study was to develop a biobarrier system containing oxygen-organic releasing material to enhance the aerobic cometabolism of TCE in situ. The oxygen-organic material, which contains calcium peroxide and peat, is able to release oxygen and primary substrates continuously upon contact with water. Batch experiments were conducted to design and identify the components of the oxygen-organic releasing material, and evaluate the oxygen and organic substrate (presented as COD equivalent) release from the designed oxygen-organic material. The observed oxygen and chemical oxygen demand (COD) release rates were approximately 0.0246 and 0.052 mg/d/g of material, respectively. A laboratory-scale column experiment was then conducted to evaluate the feasibility of this proposed system for the bioremediation of TCE-contaminated groundwater. This system was performed using a series of continuous-flow glass columns including a soil column, an oxygen-organic material column, followed by two consecutive soil columns. Aerobic acclimated sludges were inoculated in all three soil columns to provide microbial consortia for TCE biodegradation. Simulated TCE-contaminated groundwater with a flow rate of 0.25 l/day was pumped into this system. Effluent samples from each column were analyzed for TCE and other indicating parameters (e.g., pH, dissolved oxygen). Results show that the decreases in TCE concentrations were observed over a 4-month operating period. Up to 99% of TCE removal efficiency was obtained in this passive system. Results indicate that the continuously released oxygen and organic substrates from the oxygen-organic materials enhanced TCE biotransformation. Thus, the biobarrier treatment scheme has the potential to be developed into an environmentally and economically acceptable remediation technology.

  13. Study on a continuous heat integrated distillation column

    Energy Technology Data Exchange (ETDEWEB)

    Glenchur, T.; Govind, R.

    1987-12-01

    A novel continuous heat integrated distillation column called a concentric column has been studied using computer simulation. It is shown that a concentric column is a novel implementation of a thermodynamically reversible distillation column and has a lower energy loss than an ordinary distillation column. Their studies show that a concentric column has reduced column height, since the stripping section is configured concentrically around the rectifying section, and uses less utilities than a conventional column.

  14. The jet flotation column control system

    Energy Technology Data Exchange (ETDEWEB)

    Xu Zhiqiang; Ming Shangzhi; Liu Lijian; Huangfu Jinghua; Huo Sen; Zhang Rongzeng [China Univ. of Mining and Technology, Beijing (China). Mineral Processing Dept.; Yang Hongjun [Hebi Coal Mine Administrative (China)

    1998-12-31

    Compared with the conventional mechanical flotation column, the jet flotation column has the advantages of high selectivity of separation, low investment and production cost, low floor space requirement, low dosage of reagent, easy control; it is more suitable to process fine particles. Recently, many new types of flotation columns have been developed with new methods. Mineral Processing Dept., China University of Mining and Technology (Beijing) designed an aerated, double-jet flotation column in the lab and the industrial trial will be put into operation. One of the significant characteristics of the new type of flotation column is high selectivity of separation, fast bubble mineralization speed. As it is sensitive to various factors, a control system for flotation column has been developed to stabilize the working condition, and this set of control system has been operated in the lab experiment.

  15. Leaching of chromium from chromium contaminated soil: Speciation study and geochemical modeling

    National Research Council Canada - National Science Library

    Anđelković Darko H; Anđelković Tatjana D; Nikolić Ružica S; Purenović Milovan M; Blagojević Srđan D; Bojić Aleksandar Lj; Ristić Milica M

    2012-01-01

    Distribution of chromium between soil and leachate was monitored. A natural process of percolating rainwater through the soil was simulated in the laboratory conditions and studied with column leaching extraction...

  16. SNAP-TITE Composite Column Reinforcement

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Recent earthquakes throughout the world have demonstrated the vulnerabilities of older reinforced concrete columns to seismic deformation demands. The Snap Tite Composite Column Reinforcement strengthens a concrete column by confining it in an external composite jacket, which prevents the concrete from expanding during seismic activity or prolonged freeze-thaw cycles. The pre-manufactured fiberglass jacket is comprised of glass fibers and corrosion resistant isopolyester resins.

  17. Parametric resonance in concrete beam-columns

    OpenAIRE

    Sharma,Mamta R.; Singh,Arbind K; Benipal,Gurmail S

    2014-01-01

    A dynamic instability, called parametric resonance, is exhibited by undampedelastic beam-columns when under the action of pulsating axial force. The scope of the existing theory of parametric resonance is restricted to physically linear beam-columns undergoing finite lateral displacements. In this Paper, the dynamic behaviour of physically nonlinear elastic cracked concrete beam-columns under pulsating axial force and constant lateral force is investigated. The constitutive equations derived ...

  18. Method to measure soil matrix infiltration in forest soil

    Science.gov (United States)

    Zhang, Jing; Lei, Tingwu; Qu, Liqin; Chen, Ping; Gao, Xiaofeng; Chen, Chao; Yuan, Lili; Zhang, Manliang; Su, Guangxu

    2017-09-01

    Infiltration of water into forest soil commonly involves infiltration through the matrix body and preferential passages. Determining the matrix infiltration process is important in partitioning water infiltrating into the soil through the soil body and macropores to evaluate the effects of soil and water conservation practices on hillslope hydrology and watershed sedimentation. A new method that employs a double-ring infiltrometer was applied in this study to determine the matrix infiltration process in forest soil. Field experiments were conducted in a forest field on the Loess Plateau at Tianshui Soil and Water Conservation Experimental Station. Nylon cloth was placed on the soil surface in the inner ring and between the inner and outer rings of infiltrometers. A thin layer of fine sands were placed onto the nylon cloth to shelter the macropores and ensure that water infiltrates the soil through the matrix only. Brilliant Blue tracers were applied to examine the exclusion of preferential flow occurrences in the measured soil body. The infiltration process was measured, computed, and recorded through procedures similar to those of conventional methods. Horizontal and vertical soil profiles were excavated to check the success of the experiment and ensure that preferential flow did not occur in the measured soil column and that infiltration was only through the soil matrix. The infiltration processes of the replicates of five plots were roughly the same, thereby indicating the feasibility of the methodology to measure soil matrix infiltration. The measured infiltration curves effectively explained the transient process of soil matrix infiltration. Philip and Kostiakov models fitted the measured data well, and all the coefficients of determination were greater than 0.9. The wetted soil bodies through excavations did not present evidence of preferential flow. Therefore, the proposed method can determine the infiltration process through the forest soil matrix. This

  19. Blocking effect of colloids on arsenate adsorption during co-transport through saturated sand columns.

    Science.gov (United States)

    Ma, Jie; Guo, Huaming; Lei, Mei; Wan, Xiaoming; Zhang, Hanzhi; Feng, Xiaojuan; Wei, Rongfei; Tian, Liyan; Han, Xiaokun

    2016-06-01

    Transport of environmental pollutants through porous media is influenced by colloids. Co-transport of As(V) and soil colloids at different pH were systematically investigated by monitoring breakthrough curves (BTCs) in saturated sand columns. A solute transport model was applied to characterize transport and retention sites of As(V) in saturated sand in the presence of soil colloids. A colloid transport model and the DLVO theory were used to reveal the mechanism and hypothesis of soil colloid-promoted As(V) transport in the columns. Results showed that rapid transport of soil colloids, regulated by pH and ionic strength, promoted As(V) transport by blocking As(V) adsorption onto sand, although soil colloids had low adsorption for As(V). The promoted transport was more significant at higher concentrations of soil colloids (between 25 mg L(-1) and 150 mg L(-1)) due to greater blocking effect on As(V) adsorption onto the sand surfaces. The blocking effect of colloids was explained by the decreases in both instantaneous (equilibrium) As adsorption and first-order kinetic As adsorption on the sand surface sites. The discovery of this blocking effect improves our understanding of colloid-promoted As transport in saturated porous media, which provides new insights into role of colloids, especially colloids with low As adsorption capacity, in As transport and mobilization in soil-groundwater systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Column: Factors Affecting Data Decay

    Directory of Open Access Journals (Sweden)

    Kevin Fairbanks

    2012-06-01

    Full Text Available In nuclear physics, the phrase decay rate is used to denote the rate that atoms and other particles spontaneously decompose. Uranium-235 famously decays into a variety of daughter isotopes including Thorium and Neptunium, which themselves decay to others. Decay rates are widely observed and wildly different depending on many factors, both internal and external. U-235 has a half-life of 703,800,000 years, for example, while free neutrons have a half-life of 611 seconds and neutrons in an atomic nucleus are stable.We posit that data in computer systems also experiences some kind of statistical decay process and thus also has a discernible decay rate. Like atomic decay, data decay fluctuates wildly. But unlike atomic decay, data decay rates are the result of so many different interplaying processes that we currently do not understand them well enough to come up with quantifiable numbers. Nevertheless, we believe that it is useful to discuss some of the factors that impact the data decay rate, for these factors frequently determine whether useful data about a subject can be recovered by forensic investigation.(see PDF for full column

  1. pH dependence and unsuitability of fluorescein dye as a tracer for pesticide mobility studies in acid soil

    Science.gov (United States)

    Chris Peterson

    2009-01-01

    The mobility of fluorescein and bromide used as tracers in packed soil columns was investigated.Five different soils were used in two application methods: soil surface application and soil incorporation, both of which simulate accepted methods of soil application of termiticides to prevent structural infestation. The...

  2. Glyphosate bioavailability in soil.

    Science.gov (United States)

    Shushkova, Tatyana; Ermakova, Inna; Leontievsky, Alexey

    2010-06-01

    Biodegradation of glyphosate in sod-podzol soil by both the indigenous micro flora and the introduced strain Ochrobactrum anthropi GPK 3 was studied with respect to its sorption and mobility. The experiments were carried out in columns simulating the vertical soil profile. Soil samples studied were taken from soil horizons 0-10, 10-20, and 20-30 cm deep. It was found out that the most of the herbicide (up to 84%) was adsorbed by soil during the first 24 h; the rest (16%) remained in the soluble fraction. The adsorbed glyphosate was completely extractable by alkali. No irreversible binding of glyphosate was observed. By the end of the experiment (21st day), glyphosate was only found in extractable fractions. The comparison of the effect of the introduced O. anthropi GPK 3 and indigenous microbial community on the total toxicant content (both soluble and absorbed) in the upper 10 cm soil layer showed its reduction by 42% (21 mg/kg soil) and 10-12% (5 mg/kg soil), respectively. Simultaneously, 14-18% glyphosate moved to a lower 10-20 cm layer. Watering (that simulated rainfall) resulted in a 20% increase of its content at this depth; 6-8% of herbicide was further washed down to the 20-30 cm layer. The glyphosate mobility down the soil profile reduced its density in the upper layer, where it was available for biodegradation, and resulted in its concentration in lower horizons characterized by the absence (or low level) of biodegradative processes. It was shown for the first time how the herbicide biodegradation in soil can be increased manifold by introduction of the selected strain O. anthropi GPK 3.

  3. Rasch models with exchangeable rows and columns

    DEFF Research Database (Denmark)

    Lauritzen, Steffen Lilholt

    The article studies distributions of doubly infinite binary matrices with exchangeable rows and columns which satify the further property that the probability of any $m \\times n$ submatrix is a function of the row- and column sums of that matrix. We show that any such distribution is a (unique...... of existence of measures with given marginals....

  4. Circulation in gas-slurry column reactors

    Energy Technology Data Exchange (ETDEWEB)

    Clark, N.; Kuhlman, J.; Celik, I.; Gross, R.; Nebiolo, E.; Wang, Yi-Zun.

    1990-08-15

    Circulation in bubble columns, such as those used in fischer-tropsch synthesis, detracts from their performance in that gas is carried on average more rapidly through the column, and the residence time distribution of the gas in the column is widened. Both of these factors influence mass-transfer operations in bubble columns. Circulation prediction and measurement has been undertaken using probes, one-dimensional models, laser Doppler velocimetry, and numerical modeling. Local void fraction was measured using resistance probes and a newly developed approach to determining air/water threshold voltage for the probe. A tall column of eight inch diameter was constructed of Plexiglas and the distributor plate was manufactured to distribute air evenly through the base of the column. Data were gathered throughout the volume at three different gas throughputs. Bubble velocities proved difficult to measure using twin probes with cross-correlation because of radial bubble movement. A series of three-dimensional mean and RMS bubble and liquid velocity measurements were also obtained for a turbulent flow in a laboratory model of a bubble column. These measurements have been made using a three-component laser Doppler velocimeter (LDV), to determine velocity distributions non-intrusively. Finally, the gas-liquid flow inside a vertically situated circular isothermal column reactor was simulated numerically. 74 refs., 170 figs., 5 tabs.

  5. Influence of tray hydraulics on tray column

    NARCIS (Netherlands)

    Betlem, Bernardus H.L.; Rijnsdorp, J.E.; Rijnsdorp, J.E.; Azink, R.F.

    1998-01-01

    To column control, in contrast to column design, tray hold-up and dependencies of tray hold-up on the operating conditions play an important role. The essence of this article is the development of an improved model of tray hydraulics over a broad operating range and its experimental validation by

  6. Effect of soil moisture on chlorine deposition.

    Science.gov (United States)

    Hearn, John; Eichler, Jeffery; Hare, Christopher; Henley, Michael

    2014-02-28

    The effect of soil moisture on chlorine (Cl(2)) deposition was examined in laboratory chamber experiments at high Cl(2) exposures by measuring the concentration of chloride (Cl(-)) in soil columns. Soil mixtures with varying amounts of clay, sand, and organic matter and with moisture contents up to 20% (w/w) were exposed to ≈3×10(4)ppm Cl(2) vapor. For low water content soils, additional water increased the reaction rate as evidenced by higher Cl(-) concentration at higher soil moisture content. Results also showed that the presence of water restricted transport of Cl(2) into the soil columns and caused lower overall deposition of Cl(2) in the top 0.48-cm layer of soil when water filled ≈60% or more of the void space in the column. Numerical solutions to partial differential equations of Fick's law of diffusion and a simple rate law for Cl(2) reaction corroborated conclusions derived from the data. For the soil mixtures and conditions of these experiments, moisture content that filled 30-50% of the available void space yielded the maximum amount of Cl(2) deposition in the top 0.48cm of soil. Published by Elsevier B.V.

  7. Nitrogen removal by three types of bioretention columns under wetting and drying regimes

    Institute of Scientific and Technical Information of China (English)

    唐宁远; 李田

    2016-01-01

    The behaviors of inorganic nitrogen species in three types of bioretention columns under an intermittently wetting regime were investigated. The mean NH4+—N, NO3−—N and total N (TN) removal efficiencies for the conventional bioretention column (Col. T1) are 71%, 1% and 41%, for layered bioretention column with less permeable soil layer (Col. T2) the efficiencies are 83%, 84% and 82%, and for the bioretention column with submerged zone (Col. T3) the values are 63%, 31% and 53%, respectively. The best nitrogen removal is obtained using Col. T2 with relatively low infiltration rate. Adsorption during runoff dosing and nitrification during the drying period are the primary NH4+—N removal pathways. Less permeable soil and the elevated outlet promote the formation of anoxic conditions. 30%–70% of NO3−—N applied to columns in a single repetition is denitrified during the draining period, suggesting that the draining period is an important timeframe for the removal of NO3−—N. Infiltration rate controls the contact time with media during the draining periods, greatly influencing the NO3−—N removal effects. Bioretention systems with infiltration rate ranging from 3 to 7 cm/h have a great potential to remove NO3−—N.

  8. Bioretention column study of bacteria community response to salt-enriched artificial stormwater.

    Science.gov (United States)

    Endreny, Theodore; Burke, David J; Burchhardt, Kathleen M; Fabian, Mark W; Kretzer, Annette M

    2012-01-01

    Cold climate cities with green infrastructure depend on soil bacteria to remove nutrients from road salt-enriched stormwater. Our research examined how bacterial communities in laboratory columns containing bioretention media responded to varying concentrations of salt exposure from artificial stormwater and the effect of bacteria and salt on column effluent concentrations. We used a factorial design with two bacteria treatments (sterile, nonsterile) and three salt concentrations (935, 315, and 80 ppm), including a deionized water control. Columns were repeatedly saturated with stormwater or deionized and then drained throughout 5 wk, with the last week of effluent analyzed for water chemistry. To examine bacterial communities, we extracted DNA from column bioretention media at time 0 and at week 5 and used molecular profiling techniques to examine bacterial community changes. We found that bacterial community taxa changed between time 0 and week 5 and that there was significant separation between taxa among salt treatments. Bacteria evenness was significantly affected by stormwater treatment, but there were no differences in bacterial richness or diversity. Soil bacteria and salt treatments had a significant effect on the effluent concentration of NO, PO, Cu, Pb, and Zn based on ANOVA tests. The presence of bacteria reduced effluent NO and Zn concentrations by as much as 150 and 25%, respectively, while having a mixed effect on effluent PO concentrations. Our results demonstrate how stormwater can affect bacterial communities and how the presence of soil bacteria improves pollutant removal by green infrastructure.

  9. Highly efficient capillary columns packed with superficially porous particles via sequential column packing.

    Science.gov (United States)

    Treadway, James W; Wyndham, Kevin D; Jorgenson, James W

    2015-11-27

    Highly efficient capillary columns packed with superficially porous particles were created for use in ultrahigh pressure liquid chromatography. Superficially porous particles around 1.5μm in diameter were packed into fused silica capillary columns with 30, 50, and 75μm internal diameters. To create the columns, several capillary columns were serially packed from the same slurry, with packing progress plots being generated to follow the packing of each column. Characterization of these columns using hydroquinone yielded calculated minimum reduced plate heights as low as 1.24 for the most efficient 30μm internal diameter column, corresponding to over 500,000plates/m. At least one highly efficient column (minimum reduced plate height less than 2) was created for all three of the investigated column inner diameters, with the smallest diameter columns having the highest efficiency. This study proves that highly efficient capillary columns can be created using superficially porous particles and shows the efficiency potential of these particles.

  10. 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

  11. Gas Transport Parameters for Landfill Final Cover Soil: Measurements and Model Modification by Dry Bulk Density

    Science.gov (United States)

    Wickramarachchi, P. N.; Kawamoto, K.; Hamamoto, S.; Nagamori, M.; Moldrup, P.; Komatsu, T.

    2011-12-01

    Landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric methane (CH4). Until recently, landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest sources of anthropogenic CH4 emission, the final cover system should also be designed for minimizing the greenhouse gases migration into the atmosphere or the areas surrounding the landfill while securing the hydraulic performance. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil, few studies about gas transport characteristics of landfill cover soils have been done. However, recent soil-gas studies implied that the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size are key parameters to understand landfill gaseous performance. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport. In this study, the effects of compaction level and particle size fraction effects on ka and Dp for landfill final cover soil was investigated. The disturbed soil samples were taken from landfill final cover in Japan. A compaction tests were performed for the soil samples with two different size fractions (content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm, 2120 cm3) at two different compaction levels [(MP):2700 kN/m2 and (SP):600 kN/m2]. After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential of 0.98, 2.94, 9.81, 1235 kPa and with air-dried and oven-dried conditions. Results showed that measured Dp and ka values for the coarser (content. Further, compaction effort was much significant

  12. 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.

  13. Dynamic Effects of Diabatization in Distillation Columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2012-01-01

    The dynamic eects of diabatization in distillation columns are investigated in simulation with primary focus on the heat-integrated distillation column (HIDiC). A generic, dynamic, rst-principle model has been formulated, which is exible to describe various diabatic distillation congurations....... Dynamic Relative Gain Array and Singular Value Analysis have been applied in a comparative study of a conventional distillation column and a HIDiC. The study showed increased input-output coupling due to diabatization. Feasible SISO control structures for the HIDiC were also found. Control...

  14. Dynamic effects of diabatization in distillation columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens

    2013-01-01

    The dynamic effects of diabatization in distillation columns are investigated in simulation emphasizing the heat-integrated distillation column (HIDiC). A generic, dynamic, first-principle model has been formulated, which is flexible enough to describe various diabatic distillation configurations....... Dynamic Relative Gain Array and Singular Value Analysis have been applied in a comparative study of a conventional distillation column and a HIDiC. The study showed increased input-output coupling due to diabatization. Feasible SISO control structures for the HIDiC were also found and control...

  15. 29 CFR 1926.756 - Beams and columns.

    Science.gov (United States)

    2010-07-01

    ... (.46 m) from the extreme outer face of the column in each direction at the top of the column shaft. (e) Perimeter columns. Perimeter columns shall not be erected unless: (1) The perimeter columns extend a minimum of 48 inches (1.2 m) above the finished floor to permit installation of perimeter safety cables prior...

  16. Study of Suitability of Out-of-Codes Tall Slab-Column and Shearwall Structure

    Institute of Scientific and Technical Information of China (English)

    GUO Nan; ZHAO Tingting; LIN Yiying

    2012-01-01

    Abstract:The purpose of this paper is to discuss the suitability of out-of-codes tall slab-column and shearwall structure and to popularize the structure in seismic region.In the research,flat-plate floor was used in slab-column and shearwall structure in the practical engineering,the key parameters of slab-column and shearwall structure and frame-shearwall structure such as deflection,punching shear behavior,story drift and capability curve were worked out by static plastic analysis,elastic-plastic time history analysis and pushover analysis,then the suitability of out-of-codes tall slab-column and shearwall structure was evaluated.The results show that the out-of-codes tall slab-column and shearwall structure studies could satisfy the require of deflection and punching shear behavior,the story drift under 7 degree expected rare earthquake waves could satisfy the limit value in the codes and the seismic design spectrum was crossed by the capability curve of the structure and the structure could not collapse.The conclusion is that slab-column and shearwall structure with reasonable design built in Ⅱ soil site of intensity 7 seismic fortification zone can be designed higher than the limit height in the codes.

  17. Closing the Water Balance for Arid Soils - First Results from a Large Lysimeter Study

    Science.gov (United States)

    Twarakavi, N.; Chief, K.; Berli, M.; Caldwell, T. G.; Daniels, J.; Young, M.

    2011-12-01

    Many ecological and hydrological processes cannot be fully assessed without full closure of the water balance. The weighing lysimeter facility in Boulder City, NV provides an excellent opportunity to study water infiltration, redistribution, storage and evaporation of bare soils at the intermediate (meter) scale under well-defined boundary conditions. Each of three lysimeters is weighed on separate balances, with a resolution of roughly 100 g or 0.025 mm of water. Each lysimeter contains 12 m3 of repacked homogenized and layered desert soil (dimensions: 2.26 m diameter and 3 m deep) and is instrumented with 13 different sensor technologies to measure state variables including water content, matric potential, and thermal properties at 15 depth planes. An angled rhizotron tube visually monitors movement the infiltration front. Between July 2008 and 2011, 15 storm events were recorded, with the largest storm total from 19-22 December 2010 yielding 62 mm of precipitation (originally in the form of snow). By July 2011, nearly 350 mm of cumulative precipitation was recorded, and the wetting front had reached 150 cm depth. This presentation analyzes storm events over the past three years with respect to changes in total soil mass to determine the amount of infiltration, storage, and evaporation; alterations in soil moisture and matric potential profiles determined by in situ sensors; and wetting front movement observed by the rhizotron. This lysimeter facility fills a critical gap in the vadose zone hydrology of arid environments by closing the total water balance and providing discrete data on soil moisture redistribution in a 3 meter deep soil profile to evaluate and improve infiltration models.

  18. Interactions between Soil Texture and Placement of Dairy Slurry Application

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Kjærgaard, Charlotte; Rubæk, Gitte Holton

    2011-01-01

    Managing phosphorus (P) losses in soil leachate following land application of manure is key to curbing eutrophication in many regions. We compared P leaching from columns of variably textured, intact soils (20 cm diam., 20 cm high) subjected to surface application or injection of dairy cattle (Bos...... retention of particulate P and dissolved organic P, caused by placing slurry away from active flow paths in the fine-textured soil columns, as well as to chemical retention of dissolved inorganic P, caused by better contact between slurry P and soil adsorption sites. Dissolved organic P was less retained...

  19. Part 1: Vadose-zone column studies of toluene (enhanced bioremediation) in a shallow unconfined aquifer

    Science.gov (United States)

    Tindall, J.A.; Friedel, M.J.; Szmajter, R.J.; Cuffin, S.M.

    2005-01-01

    The objectives of the laboratory study described in this paper were (1) to determine the effectiveness of four nutrient solutions and a control in stimulating the microbial degradation of toluene in the unsaturated zone as an alternative to bioremediation methodologies such as air sparging, in situ vitrification, or others (Part I), and (2) to compare the effectiveness of the addition of the most effective nutrient solution from Part I (modified Hoagland type, nitrate-rich) and hydrogen peroxide (H2O2) on microbial degradation of toluene for repeated, simulated spills in the unsaturated zone (Part II). For Part 1, fifteen columns (30-cm diameter by 150-cm height), packed with air-dried, 0.25-mm, medium-fine sand, were prepared to simulate shallow unconfined aquifer conditions. Toluene (10 mL) was added to the surface of each column, and soil solution and soil gas samples were collected from the columns every third day for 21 days. On day 21, a second application of toluene (10 mL) was made, and the experiment was run for another 21 days. Solution 4 was the most effective for microbial degradation in Part I. For Part II, three columns were designated nutrient-rich 3-day toluene columns and received toluene injections every 3 days; three columns were designated as nutrient-rich 7-day columns and received toluene injections every 7 days; and two columns were used as controls to which no nutrient was added. As measured by CO2 respiration, the initial benefits for aerobic organisms from the O2 enhancement were sustained by the bacteria for only a short period of time (about 8 days). Degradation benefits from the nutrient solution were sustained throughout the experiment. The O2 and nutrient-enhanced columns degraded significantly more toluene than the control columns when simulating repeated spills onto the unsaturated zone, and demonstrated a potentially effective in situ bioremediation technology when used immediately or within days after a spill. The combined usage

  20. Enantioselective Degradation of Triadimefon in Green-house Soil

    Directory of Open Access Journals (Sweden)

    Liu Hong Cheng

    2015-09-01

    Full Text Available To study enantioselctive degradation of triadimefon, the enantioselective degradation of triadimefon in greenhouse soil and normal soil were investigated in detail. The enantiomers of triadimefon were separated by Chiralpak AD column and determined by Liquid Chromatography Via Tandem Mass Spectrometry (LC-MS/MS. The degradation exhibited some enantioselective, resulting in a concentration order of R-(- tridimefon>S-(+ triadimefon and the degradation of triadimefon in greenhouse soils with high content of organic matter was faster than normal soil.

  1. Electroosmotic Driving Liquid Using Nanosilica Packed Column

    Institute of Scientific and Technical Information of China (English)

    Ling Xin CHEN; Guo An LUO; Tao WEN

    2005-01-01

    The electroosmotic pump (EOP) using nanosilica particles packed-bed column was experimentally studied. The relationship between flowrate, pressure and applied voltage of the pump, and pressure-flowrate (P-Q) characteristic were investigated.

  2. Early development of the vertebral column.

    Science.gov (United States)

    Scaal, Martin

    2016-01-01

    The segmental organization of the vertebrate body is most obviously visible in the vertebral column, which consists of a series of vertebral bones and interconnecting joints and ligaments. During embryogenesis, the vertebral column derives from the somites, which are the primary segments of the embryonic paraxial mesoderm. Anatomical, cellular and molecular aspects of vertebral column development have been of interest to developmental biologists for more than 150 years. This review briefly summarizes the present knowledge on early steps of vertebral column development in amniotes, starting from sclerotome formation and leading to the establishment of the anatomical bauplan of the spine composed of vertebral bodies, vertebral arches, intervertebral discs and ribs, and their specific axial identities along the body axis.

  3. Modeling Tropical Precipitation in a Single Column.

    Science.gov (United States)

    Sobel, Adam H.; Bretherton, Christopher S.

    2000-12-01

    A modified formulation of the traditional single column model for representing a limited area near the equator is proposed. This formulation can also be considered a two-column model in the limit as the area represented by one of the columns becomes very large compared to the other. Only a single column is explicitly modeled, but its free tropospheric temperature, rather than its mean vertical velocity, is prescribed. This allows the precipitation and vertical velocity to be true prognostic variables, as in prior analytical theories of tropical precipitation. Two models developed by other authors are modified according to the proposed formulation. The first is the intermediate atmospheric model of J. D. Neelin and N. Zeng, but with the horizontal connections between columns broken, rendering it a set of disconnected column models. The second is the column model of N. O. Rennó, K. A. Emanuel, and P. H. Stone. In the first model, the set of disconnected column models is run with a fixed temperature that is uniform in the Tropics, and insolation, SST, and surface wind speed taken from a control run of the original model. The column models produce a climatological precipitation field that is grossly similar to that of the control run, despite that the circulation implied by the column models is not required to conserve mass. The addition of horizontal moisture advection by the wind from the control run substantially improves the simulation in dry regions. In the second model the sensitivity of the modeled steady-state precipitation and relative humidity to varying SST and wind speed is examined. The transition from shallow to deep convection is simulated in a `Lagrangian' calculation in which the column model is subjected to an SST that increases in time. In this simulation, the onset of deep convection is delayed to a higher SST than in the steady-state case, due to the effect of horizontal moisture advection (viewed in a Lagrangian reference frame). In both of the

  4. Nonlinear control of high purity distillation columns

    OpenAIRE

    Groebel, Markus; Allgöwer, Frank; Storz, Markus; Gilles, Ernst Dieter

    1994-01-01

    Two simple models of distillation columns are studied to investigate their suitability for the practical use with exact I/O-linearization. An extension of exact I/O-linearization, the asymptotically exact I/O-linearization is applied to the control of a high purity distillation column, using one of these models to derive the static state feedback law. Simulation studies demonstrate the advantage of asymptotically exact I/O-linearization versus classical exact I/O-linearization techniques. Exp...

  5. The Dissipative Column: A New Hysteretic Damper

    OpenAIRE

    Bruno Palazzo; Paolo Castaldo; Ivana Marino

    2015-01-01

    A new replaceable hysteretic damper to better control seismic building damage, consisting of two or more adjacent steel vertical elements connected to each other with continuous mild/low strength steel shear links, is proposed and investigated in this paper. New Dampers, called Dissipative Columns (DC), continuously linked with X-shaped steel plates, provide additional stiffness and damping to a lateral system by using a basic and minimally invasive construction element: the column. Working i...

  6. Fuzzy Based composition Control of Distillation Column

    Directory of Open Access Journals (Sweden)

    Guru.R

    2013-04-01

    Full Text Available This paper proposed a control scheme based on fuzzy logic for a methanol - water system of bubble cap distillation column. Fuzzy rule base and Inference System of fuzzy (FIS is planned to regulatethe reflux ratio (manipulated variable to obtain the preferred product composition (methanol for a distillation column. Comparisons are made with conventional controller and the results confirmed the potentials of the proposed strategy of fuzzy control.

  7. Enhancing Bioremediation of Oil-contaminated Soils by Controlling Nutrient Transport using Dual Characteristics of Soil Pore Structure

    Science.gov (United States)

    Mori, Y.; Suetsugu, A.; Matsumoto, Y.; Fujihara, A.; Suyama, K.; Miyamoto, T.

    2012-12-01

    Soil structure is heterogeneous with cracks or macropores allowing bypass flow, which may lead to applied chemicals avoiding interaction with soil particles or the contaminated area. We investigated the bioremediation efficiency of oil-contaminated soils by applying suction at the bottom of soil columns during bioremediation. Unsaturated flow conditions were investigated so as to avoid bypass flow and achieve sufficient dispersion of chemicals in the soil column. The boundary conditions at the bottom of the soil columns were 0 kPa and -3 kPa, and were applied to a volcanic ash soil with and without macropores. Unsaturated flow was achieved with -3 kPa and an injection rate of 1/10 of the saturated hydraulic conductivity. The resultant biological activities of the effluent increased dramatically in the unsaturated flow with macropores condition. Unsaturated conditions prevented bypass flow and allowed dispersion of the injected nutrients. Unsaturated flow achieved 60-80% of saturation, which enhanced biological activity in the soil column. Remediation results were better for unsaturated conditions because of higher biological activity. Moreover, unsaturated flow with macropores achieved uniform remediation efficiency from upper through lower positions in the column. Finally, taking the applied solution volume into consideration, unsaturated flow with -3 kPa achieved 10 times higher efficiency when compared with conventional saturated flow application. These results suggest that effective use of nutrients or remediation chemicals is possible by avoiding bypass flow and enhancing biological activity using relatively simple and inexpensive techniques.

  8. X-ray CT Scanning Reveals Long-Term Copper Pollution Effects on Functional Soil Structure

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Møldrup, Per; Homstrup, Martin

    Soil structure plays the main role in the ability of the soil to fulfill essential soil functions such as the root growth, rate of water infiltration and retention, transport of gaseous and chemicals/pollutants through the soil. Soil structure is a dynamic soil property and affected by various...... factors such as soil type, land use, and soil contamination. In this study, we quantified the soil structure using X-ray CT scanning and revealed the effect of a long history of Copper (Cu) pollution on it. A fallow field at Hygum Denmark provides this opportunity as it had a long history of Copper...... columns, macroporosity showed a significant decrease along the column depth. The results suggest that Cu contamination has a strong impact on soil structure and hence on all soil physical and biological processes....

  9. The handedness of historiated spiral columns.

    Science.gov (United States)

    Couzin, Robert

    2016-11-17

    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.

  10. 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

  11. DOE/SC0001389 Final technical report: Investigation of uranium attenuation and release at column and pore scales in response to advective geochemical gradients

    Energy Technology Data Exchange (ETDEWEB)

    Savage, Kaye S. [Wofford College; Zhu, Wenyi [Wofford College; Barnett, Mark O. [Auburn University

    2013-05-13

    Experimental approach Column experiments were devised to investigate the role of changing fluid composition on mobility of uranium through a sequence of geologic media. Fluids and media were chosen to be relevant to the ground water plume emanating from the former S-3 ponds at the Oak Ridge Integrated Field Research Challenge (ORIFC) site. Synthetic ground waters were pumped upwards at 0.05 mL/minute for 21 days through layers of quartz sand alternating with layers of uncontaminated soil, quartz sand mixed with illite, quartz sand coated with iron oxides, and another soil layer. Increases in pH or concentration of phosphate, bicarbonate, or acetate were imposed on the influent solutions after each 7 pore volumes while uranium (as uranyl) remained constant at 0.1mM. A control column maintained the original synthetic groundwater composition with 0.1mM U. Pore water solutions were extracted to assess U retention and release in relation to the advective ligand or pH gradients. Following the column experiments, subsamples from each layer were characterized using microbeam X-ray absorption spectroscopy (XANES) in conjunction with X-ray fluorescence mapping and compared to sediment core samples from the ORIFC, at SSRL Beam Line 2-3. Results U retention of 55-67mg occurred in phosphate >pH >control >acetate >carbonate columns. The mass of U retained in the first-encountered quartz layer in all columns was highest and increased throughout the experiment. The rate of increase in acetate- and bicarbonate-bearing columns declined after ligand concentrations were raised. U also accumulated in the first soil layer; the pH-varied column retained most, followed by the increasing-bicarbonate column. The mass of U retained in the upper layers was far lower. Speciation of U, interpreted from microbeam XANES spectra and XRF maps, varied within and among the columns. Evidence of minor reduction to U(IV) was observed in the first-encountered quartz layer in the phosphate, bicarbonate

  12. Studies and research concerning BNFP pilot-scale pulsed columns: column profile and holdup studies

    Energy Technology Data Exchange (ETDEWEB)

    Cermak, A. F.

    1980-11-01

    Experimental studies were conducted on pilot-scaled pulsed columns for the purpose of obtaining data for verification of contactor computer programs. This work is in support of safeguards programs related to determination of near real-time inventories in pulsed columns. Holdup tests were performed resulting in the derivation of an empirical equation for estimation of the dispersed phase holdup in a column. Uranium solvent extraction mass-transfer tests were conducted in which all four process cycles were simulated under coprocessing flowsheet conditions. Extensive data were obtained during these tests on uranium profiles and inventories within the columns. Transient profile data were also determined between selected runs under the tested operating conditions. No concentration peaks could be observed during the transient period. Based on the extensive inventory data taken, empirical equations were developed for relating uranium inventory in a column to the test parameters. These equations were found useful for predicting and estimating the column inventory under the known run conditions.

  13. Effect of Thickness of a Water Repellent Soil Layer on Soil Evaporation Rate

    Science.gov (United States)

    Ahn, S.; Im, S.; Doerr, S.

    2012-04-01

    A water repellent soil layer overlying wettable soil is known to affect soil evaporation. This effect can be beneficial for water conservation in areas where water is scarce. Little is known, however, about the effect of the thickness of the water repellent layer. The thickness of this layer can vary widely, and particularly after wildfire, with the soil temperature reached and the duration of the fire. This study was conducted to investigate the effect of thickness of a top layer of water repellent soil on soil evaporation rate. In order to isolate the thickness from other possible factors, fully wettable standard sand (300~600 microns) was used. Extreme water repellency (WDPT > 24 hours) was generated by 'baking' the sand mixed with oven-dried pine needles (fresh needles of Pinus densiflora) at the mass ratio of 1:13 (needle:soil) at 185°C for 18 hours. The thicknesses of water repellent layers were 1, 2, 3 and 7 cm on top of wettable soil. Fully wettable soil columns were prepared as a control. Soil columns (8 cm diameter, 10 cm height) were covered with nylon mesh. Tap water (50 ml, saturating 3 cm of a soil column) was injected with hypoderm syringes from three different directions at the bottom level. The injection holes were sealed with hot-melt adhesive immediately after injection. The rate of soil evaporation through the soil surface was measured by weight change under isothermal condition of 40°C. Five replications were made for each. A trend of negative correlation between the thickness of water repellent top layer and soil evaporation rate is discussed in this contribution.

  14. Effect of Soil Passage and Ozonation on Dissolved Organic Carbon and Microbial Quantification in Wastewater

    KAUST Repository

    Ahmed, Elaf A.

    2013-05-01

    Water quality data are presented from a laboratory bench scale soil columns study, to simulate an aquifer recharge system injected with MBR wastewater effluent. This study investigates the effect of soil filtration and ozonation on the dissolved organic carbon and bacterial count in the wastewater. Flow Cytometry was used to quantify microorganisms in water samples. Other analytical tests were conducted as well, such as seven anions, fluorescence spectroscopy (FEEM), ultraviolet absorption (UV 254 nm) and dissolved organic carbon measurement (DOC). Influent in this study was injected into two identical soil columns. One of the columns was injected with treated wastewater combined with ozonation called SC1, The second column was injected with treated wastewater only and called SC2. Passing the wastewater through a deeper depth in the soil column showed a reduction in the DOC concentration. Removal of DOC was 53.7 % in SC1 and 53.8 % in SC2. UV 254 nm results demonstrated that the majority of the UV absorbing compounds were removed after the first 30 cm in the soil columns. FEEM results revealed that soil column treatment only doesn\\'t remove humic-like and fulvic-like substances. However, combining soil column treatment with ozonation was capable of removing humic-like, fulvic-like and protein-like substances from the wastewater. Flow Cytometry results showed a bacteria removal of 52.5 %-89.5 % in SC1 which was higher than SC2 removal of 29.1 %-56.5 %.

  15. A mathematical model for isothermal heap and column leaching

    Directory of Open Access Journals (Sweden)

    Lima L.R.P. de Andrade

    2004-01-01

    Full Text Available Leaching occurs in metals recovery, in contaminated soil washing, and in many natural processes, such as fertilizer dissolution and rock weathering. This paper presents a model developed to simulate the transient evolution of the dissolved chemical species in the heap and column isothermal leaching processes. In this model, the solid bed is numerically divided into plane layers; the recovery of the chemical species, the enrichment of the pregnant leach solution, and the residual concentration of the leaching agent are calculated by interactions among the layers. The solution flow in the solid bed is assumed as unidirectional without dispersion, and the solid-fluid reaction is described by a diffusive control model that is integrated analytically for each time step. The data set used in the model include physical-chemical, geometrical, and operational variables, such as: leachable chemical species content, leaching agent flow rate and concentration, particles size distribution, solution residence time in the solid bed, and solid bed length, weight and irrigated area. The results for two case studies, namely, an industrial gold heap leaching and a pilot column copper acid leaching, showed that the model successful predict the general features of the process time evolution.

  16. Using polymer mats to biodegrade atrazine in groundwater: laboratory column experiments

    Science.gov (United States)

    Patterson, B. M.; Franzmann, P. D.; Davis, G. B.; Elbers, J.; Zappia, L. R.

    2002-02-01

    Large-scale column experiments were undertaken to evaluate the potential of in situ polymer mats to deliver oxygen into groundwater to induce biodegradation of the pesticides atrazine, terbutryn and fenamiphos contaminating groundwater in Perth, Western Australia. The polymer mats, composed of woven silicone (dimethylsiloxane) tubes and purged with air, were installed in 2-m-long flow-through soil columns. The polymer mats proved efficient in delivering dissolved oxygen to anaerobic groundwater. Dissolved oxygen concentrations increased from biodegradation rates, suggesting that organic carbon was not limiting biodegradation. Atrazine degradation rates estimated in the column experiments were similar to rates determined in laboratory culture experiments, using pure cultures of atrazine-mineralising bacteria. No significant degradation of terbutryn or fenamiphos was observed under the experimental conditions within the time frames of the study. Results from these experiments indicate that remediation of atrazine in a contaminated aquifer may be achievable by delivery of oxygen using an in situ polymer mat system.

  17. Structural Decoupling and Disturbance Rejection in a Distillation Column

    DEFF Research Database (Denmark)

    Bahar, Mehrdad; Jantzen, Jan; Commault, C.

    1996-01-01

    Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references.......Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references....

  18. 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.

  19. Transport and Fate of Nitroaromatic and Nitramine Explosives in Soils from Open Burning/Open Detonation Operations: Milan Army Ammunition Plant (MAAP)

    Science.gov (United States)

    1993-12-01

    20 e. Harvest of Soil Columns ............................ 20 f. CESMU System Integrity ............................. 21 g. Determination of...ci-nducted 01 Ot/OD) residuos and ý_PL-vut 𔄁 explosives (results- lcpricd ak’ iiaely ilk -ii thcr trVnaa epor-t enititledi ’ioyicity of S1-oected...collection tubes were inert hydrophobic barriers that remained an integral part of the soil-core columns. Thus disruption of the soil due to column-to

  20. Column flotation of bitumen at Fort Hills

    Energy Technology Data Exchange (ETDEWEB)

    Lizama, H.M. [Teck Cominco, Vancouver, BC (Canada); Romero, D. [UTS Energy Corp., Calgary, AB (Canada); Armour, M. [Petro-Canada, Calgary, AB (Canada)

    2008-05-15

    Flotation columns are used by mineral processors to separate mineral species. The separation is based on the premise that different mineral particles have different surface hydrophobicities. There are 2 carrier phases, notably air bubbles moving up and aqueous pulp moving down. Hydrophobic particles predominantly adhere to rising air bubbles and form a froth, while hydrophilic particles remain in aqueous suspension and flow down and out the bottom of the column. This paper described a demonstration plant near Fort McMurray where bitumen extraction was tested. The plant included 2 columns for bitumen flotation. Oil sands material was passed through a roll sizer and fed to a countercurrent drum separator, where it was mixed with water at 75 degrees C. Column data from the demonstration plant provided the opportunity to examine the separation behaviour during flotation of bitumen. The bitumen grade was described only in terms of bitumen content and solids content in order to simplify the interpretation of the bitumen flotation data. Bitumen/solids separation in the first column was successful at 50 to 60 degrees C, with feeds having bitumen grades between 1 and 19 per cent, and where the solids had about 60 per cent fines. Bitumen/solids separation did not occur in the second column at 50 to 60 degrees C, with feeds having bitumen grades between 8 and 63 per cent, and where the solids had about 90 per cent fines. The lack of separation was probably due to high solids entrainment in the flotation froth. It was concluded that bitumen column flotation data can be analyzed and interpreted by adopting mineral processing principles. Bitumen/solids separation can be evaluated and predicted by plotting solids recovery as a function of bitumen recovery. 7 refs., 1 tab., 6 figs.

  1. How far roots and exudates can transform the soil structure and porosity?

    Science.gov (United States)

    Johannes, Alice; Kohler-Milleret, Roxane; Lamy, Frédéric; Boivin, Pascal

    2014-05-01

    Aims The impact of plant-roots on soil physical porosity and structure is still to be deciphered. Recent results revealed root-induced increases in soil pore volume whose magnitude could not be attributed to root-drilling effect, thus suggesting an indirect effect via microbial activity enhanced by root exudates (Milleret et al., 2009, Kholer-Milleret et al., 2013). This is discussed in the present study by quantifying the soil hydro-structural changes induced by root exudates and microorganisms in the absence of roots. Methods The experiment was performed on series of structured repacked samples from two soils previously experimented with plants in mesocosms (Anthrosol and Luvisol). The samples received a daily input of artificial root exudates for three months. The soil structural changes were then assessed using shrinkage analysis and aggregate stability test. Microbial activity was measured with CO2 emanation. Results In agreement with previous findings, root exudates increased microbial activity and aggregate stability. Oppositely, the observed structural changes were contradictory both in magnitude and pattern with those observed in the presence of plant roots. The soil bulk porosity was almost not changed while the small-diameter structural porosity was decreased in the presence of root exudates. Moreover, the hydro-structural stability of the soil decreased while the aggregate stability increased. Conclusions Though the structural changes observed in the presence of roots cannot be attributed to direct root drilling effect, they are not observed when only root exudates are delivered to the soil. Our results suggest that the soil structure is engineered by a complex soil-plant-microbe interaction combining root mechanical effect and micro-aggregate stabilisation effect. Cumulative structural pore volume increase could result from aggregates rearrangements induced by root growth, either by drilling or lever effect, further stabilized by microorganism

  2. 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.

  3. The Impact of Different Fertigation Practices and Initial Soil Salinity on Soil N and Salinity Transport

    Directory of Open Access Journals (Sweden)

    Zeng Wen-zhi

    2013-04-01

    Full Text Available For studying the impact of different fertigation practices and initial soil salinity on soil N and salinity transport, large Plexi-glass columns (18.2 cm in diameter and 100 cm long assembled from sandy loam (Inner Mongolia and saturation optimum design were employed to simulate a range of initial soil salinity conditions in soil profile and fertigation practices. (4~8 L solution with 20 g urea dissolved was applied evenly and slowly to the surface of each column. Nitrate and ammonium nitrogen in soil and discharge from the outlet were sampled and the electrical conductivity of soil and the chloride ion concentration of discharges were also measured. Findings from this study include: (1 high initial salinity in soil had a certain impact on the changes of water content of vertical soil section with the time being after large amount of water irrigation and it might increase the rate of infiltration; (2 the amount of irrigation water significantly affected the transport of soil salinity; (3 high soil salinity content was likely to promote the conversion of urea nitrogen to ammonium nitrogen and it might also play an active role in ammonium nitrogen accumulation in drainage; (4 There is a sound linear relation between the cumulative content of chloride ion and that of nitrate nitrogen in the drainage and soil profile (r2 = 0.8221 and 0.7442.

  4. Post Column Derivatization Using Reaction Flow High Performance Liquid Chromatography Columns.

    Science.gov (United States)

    Jones, Andrew; Pravadali-Cekic, Sercan; Hua, Stanley; Kocic, Danijela; Camenzuli, Michelle; Dennis, Gary; Shalliker, Andrew

    2016-04-26

    A protocol for the use of reaction flow high performance liquid chromatography columns for methods employing post column derivatization (PCD) is presented. A major difficulty in adapting PCD to modern HPLC systems and columns is the need for large volume reaction coils that enable reagent mixing and then the derivatization reaction to take place. This large post column dead volume leads to band broadening, which results in a loss of observed separation efficiency and indeed detection in sensitivity. In reaction flow post column derivatization (RF-PCD) the derivatization reagent(s) are pumped against the flow of mobile phase into either one or two of the outer ports of the reaction flow column where it is mixed with column effluent inside a frit housed within the column end fitting. This technique allows for more efficient mixing of the column effluent and derivatization reagent(s) meaning that the volume of the reaction loops can be minimized or even eliminated altogether. It has been found that RF-PCD methods perform better than conventional PCD methods in terms of observed separation efficiency and signal to noise ratio. A further advantage of RF-PCD techniques is the ability to monitor effluent coming from the central port in its underivatized state. RF-PCD has currently been trialed on a relatively small range of post column reactions, however, there is currently no reason to suggest that RF-PCD could not be adapted to any existing one or two component (as long as both reagents are added at the same time) post column derivatization reaction.

  5. Robust Matrix Completion with Corrupted Columns

    CERN Document Server

    Chen, Yudong; Caramanis, Constantine; Sanghavi, Sujay

    2011-01-01

    This paper considers the problem of matrix completion, when some number of the columns are arbitrarily corrupted, potentially by a malicious adversary. It is well-known that standard algorithms for matrix completion can return arbitrarily poor results, if even a single column is corrupted. What can be done if a large number, or even a constant fraction of columns are corrupted? In this paper, we study this very problem, and develop an efficient algorithm for its solution. Our results show that with a vanishing fraction of observed entries, it is nevertheless possible to succeed in performing matrix completion, even when the number of corrupted columns grows. When the number of corruptions is as high as a constant fraction of the total number of columns, we show that again exact matrix completion is possible, but in this case our algorithm requires many more -- a constant fraction -- of observations. One direct application comes from robust collaborative filtering. Here, some number of users are so-called mani...

  6. Bioventing remediation and ecotoxicity evaluation of phenanthrene-contaminated soil.

    Science.gov (United States)

    García Frutos, F Javier; Escolano, Olga; García, Susana; Babín, Mar; Fernández, M Dolores

    2010-11-15

    The objectives of soil remediation processes are usually based on threshold levels of soil contaminants. However, during remediation processes, changes in bioavailability and metabolite production can occur, making it necessary to incorporate an ecotoxicity assessment to estimate the risk to ecological receptors. The evolution of contaminants and soil ecotoxicity of artificially phenanthrene-contaminated soil (1000 mg/kg soil) during soil treatment through bioventing was studied in this work. Bioventing was performed in glass columns containing 5.5 kg of phenanthrene-contaminated soil and uncontaminated natural soil over a period of 7 months. Optimum conditions of mineralisation (humidity=60% WHC; C/N/P=100:20:1) were determined in a previous work. The evolution of oxygen consumption, carbon dioxide production, phenanthrene concentration and soil toxicity were studied on sacrificed columns at periods of 0, 3 and 7 months. Toxicity to soil and aquatic organisms was determined using a multispecies system in the soil columns (MS-3). In the optimal bioventing treatability test, we obtained a reduction rate in phenanthrene concentration higher that 93% after 7 months of treatment. The residual toxicity obtained at the end of the treatment was not attributed to the low phenanthrene concentration, but to the ammonia used to restore the optimal C/N ratio.

  7. Dynamic effects of wet-dry cycles and crust formation on the saturated hydraulic conductivity of surface soils in the constructed Hühnerwasser ("Chicken Creek") catchment

    Science.gov (United States)

    Hinz, Christoph; Schümberg, Sabine; Kubitz, Anita; Frank, Franzi; Cheng, Zhang; Nanu Frechen, Tobias; Pohle, Ina

    2016-04-01

    Highly disturbed soils and substrates used in land rehabilitation undergo rapid changes after the first wetting events which in turn can lead to ecosystem degradation. Such changes were detected during the early development of the constructed Hühnerwasser ("Chicken Creek") catchment in Lusatia, Germany. Surface substrates consisting of quaternary sandy sediments formed surface seals during the first rainfall events leading to reduced infiltration and substantially increased surface runoff. Subsequently biological soil crusts formed and stabilised the surface. The aim of this study is to investigate the factors that cause the hydraulic conductivity to decrease using undisturbed and disturbed soil samples. Based on the hypothesis that physical and biological crusts lower the hydraulic conductivity, the first set of experiments with undisturbed soil cores from the Hühnerwasser catchment were carried out to measure the saturated hydraulic conductivity using the constant head method. Measurements were done with intact cores and repeated after the surface crust was removed. As the quaternary glacial sediments tend to display hard setting behaviour, we further hypothesised that the mobilisation of fine particles within the cores lead to pore clogging and that wet-dry cycles will therefore decrease hydraulic conductivity. A second set of experiments using the same methodology consisted of five repeated measurements of hydraulic conductivity after each drying cycle. These measurements were done with undisturbed core samples as well as repacked cores in order to assess how dry packing affects the dynamics of the hydraulic conductivity somewhat similar to the situation during the first wetting after completion of the catchment construction. For all experiments, the temporal evolution of hydraulic conductivity was measured and the turbidity of the effluent was recorded. The results clearly demonstrated that the substrate is highly unstable. The first set of experiments

  8. Model prediction uncertainty of bromide and pesticides transport in laboratory column

    Science.gov (United States)

    Dusek, Jaromir; Dohnal, Michal; Snehota, Michal; Sobotkova, Martina; Ray, Chittaranjan; Vogel, Tomas

    2016-04-01

    Knowledge of transport parameters of reactive solutes such as pesticides is a prerequisite for reliable predictions of their fate and transport in soil porous systems. Water flow and transport of bromide tracer and five pesticides (atrazine, imazaquin, sulfometuron methyl, S-metolachlor, and imidacloprid) through an undisturbed soil column of tropical Oxisol were analyzed using a one-dimensional numerical model. Laboratory column leaching experiment with three flow interruptions was conducted. The applied numerical model is based on Richards' equation for solving water flow and the advection-dispersion equation for solving solute transport. A global optimization method was used to evaluate the model's sensitivity to transport parameters and the uncertainty of model predictions. Within the Monte Carlo modeling framework, multiple forward simulations searching through the parametric space, were executed to describe the observed breakthrough curves. All pesticides were found to be relatively mobile. Experimental data indicated significant non-conservative behavior of bromide tracer. All pesticides, with the exception of imidacloprid, were found less persistent. Three of the five pesticides (atrazine, sulfometuron methyl, and S-metolachlor) were better described by the linear kinetic sorption model, while the breakthrough curves of imazaquin and imidacloprid were more appropriately approximated using nonlinear instantaneous sorption. Sensitivity analysis suggested that the model is most sensitive to sorption distribution coefficient. The prediction limits contained most of the measured points of the experimental breakthrough curves, indicating adequate model concept and model structure for the description of transport processes in the soil column under study.

  9. Stone column settlement performance in structured anisotropic clays:the influence of creep

    Institute of Scientific and Technical Information of China (English)

    Brian G. Sexton; Bryan A. McCabe; Minna Karstunen; Nallathamby Sivasithamparam

    2016-01-01

    The recently developed elasto-viscoplastic Creep-SCLAY1S model has been used in conjunction with PLAXIS 2D to investigate the effectiveness of vibro-replacement in a creep-prone clay. The Creep-SCLAY1S model accounts for anisotropy, bonding, and destructuration, and uses the concept of a con-stant rate of viscoplastic multiplier to calculate creep strain rate. A comparison of settlement improve-ment factors with and without creep indicates that‘total’ settlement improvement factors (primary plus creep) are lower than their ‘primary’ counterparts (primary settlement only). The lowest settlement improvement factors arise for analyses incorporating the effect of bonding and destructuration. Exam-ination of the variations of vertical stress with time and depth has indicated that vertical stress is transferred from the soil to the column as the soil creeps. This results in additional column yielding. In addition, the radial and hoop stresses in the soil are lower for the‘creep’ case. The reduced radial stresses lead to additional column bulging and hence more settlement, whereas the hoop stress reductions appear to be a secondary effect, caused by additional plastic deformation for the‘creep’ case.

  10. Stone column settlement performance in structured anisotropic clays: the influence of creep

    Directory of Open Access Journals (Sweden)

    Brian G. Sexton

    2016-10-01

    Full Text Available The recently developed elasto-viscoplastic Creep-SCLAY1S model has been used in conjunction with PLAXIS 2D to investigate the effectiveness of vibro-replacement in a creep-prone clay. The Creep-SCLAY1S model accounts for anisotropy, bonding, and destructuration, and uses the concept of a constant rate of viscoplastic multiplier to calculate creep strain rate. A comparison of settlement improvement factors with and without creep indicates that ‘total’ settlement improvement factors (primary plus creep are lower than their ‘primary’ counterparts (primary settlement only. The lowest settlement improvement factors arise for analyses incorporating the effect of bonding and destructuration. Examination of the variations of vertical stress with time and depth has indicated that vertical stress is transferred from the soil to the column as the soil creeps. This results in additional column yielding. In addition, the radial and hoop stresses in the soil are lower for the ‘creep’ case. The reduced radial stresses lead to additional column bulging and hence more settlement, whereas the hoop stress reductions appear to be a secondary effect, caused by additional plastic deformation for the ‘creep’ case.

  11. Soils - NRCS Web Soil Survey

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Web Soil Survey (WSS) provides soil data and information produced by the National Cooperative Soil Survey. It is operated by the USDA Natural Resources Conservation...

  12. Effect of pH and soil structure on transport of sulfonamide antibiotics in agricultural soils.

    Science.gov (United States)

    Park, Jong Yol; Huwe, Bernd

    2016-06-01

    We investigated the effect of solution pH and soil structure on transport of sulfonamide antibiotics (sulfamethoxazole, sulfadimethoxine and sulfamethazine) in combination with batch sorption tests and column experiments. Sorption isotherms properly conformed to Freundlich model, and sorption potential of the antibiotics is as follows; sulfadimethoxine > sulfamethoxazole > sulfamethazine. Decreasing pH values led to increased sorption potential of the antibiotics on soil material in pH range of 4.0-8.0. This likely resulted from abundance of neutral and positive-charged sulfonamides species at low pH, which electrostatically bind to sorption sites on soil surface. Due to destruction of macropore channels, lower hydraulic conductivities of mobile zone were estimated in the disturbed soil columns than in the undisturbed soil columns, and eventually led to lower mobility of the antibiotics in disturbed column. The results suggest that knowledge of soil structure and solution condition is required to predict fate and distribution of sulfonamide antibiotics in environmental matrix.

  13. Guar gum coupled microscale ZVI for in situ treatment of CAHs: continuous-flow column study.

    Science.gov (United States)

    Velimirovic, Milica; Simons, Queenie; Bastiaens, Leen

    2014-01-30

    A column study was performed under in situ conditions to evaluate to which extend the inactivation of the microscale zerovalent iron (mZVI) by guar gum occurs under continuous flow conditions. Five aquifer containing columns were set up under different conditions. Efficient removal of trichloroethene was observed for the column amended by mZVI. Stabilization of the mZVI with guar gum led to slightly reduced activity. More reduced reactivity was observed in the poisoned column containing guar gum stabilized mZVI. This confirms that soil microorganisms can degrade guar gum and that subsequent removal of the oligosaccharides by the groundwater flow (flushing effect) can reactivate the mZVI. After more than six months of continuous operation the columns were dismantled. DNA-based qPCR analysis revealed that mZVI does not significantly affect the bacterial community, while guar gum stabilized mZVI particles can even induce bacterial growth. Overall, this study suggests that the temporarily decreased mZVI reactivity due to guar gum, has a rather limited impact on the performance of in situ reactive zones. The presence of guar gum slightly reduced the reactivity of iron, but also slowed down the iron corrosion rate which prolongs the life time of reactive zone.

  14. Buckling driven debonding in sandwich columns

    DEFF Research Database (Denmark)

    Østergaard, Rasmus Christian

    2008-01-01

    A compression loaded sandwich column that contains a debond is analyzed using a geometrically non-linear finite element model. The model includes a cohesive zone along one face sheet/core interface whereby the debond can extend by interface crack growth. Two geometrical imperfections are introduced......; a global imperfection of the sandwich column axis and a local imperfection of the debonded face sheet axis. The model predicts the sandwich column to be very sensitive to the initial debond length and the local face sheet imperfection. The study shows that the sensitivity to the face sheet imperfection...... results from two mechanisms: (a) interaction of local debond buckling and global buckling and (b) the development of a damaged zone at the debond crack tip. Based on the pronounced imperfection sensitivity, the author predicts that an experimental measurement of the strength of sandwich structures may...

  15. Non-planar microfabricated gas chromatography column

    Science.gov (United States)

    Lewis, Patrick R.; Wheeler, David R.

    2007-09-25

    A non-planar microfabricated gas chromatography column comprises a planar substrate having a plurality of through holes, a top lid and a bottom lid bonded to opposite surfaces of the planar substrate, and inlet and outlet ports for injection of a sample gas and elution of separated analytes. A plurality of such planar substrates can be aligned and stacked to provide a longer column length having a small footprint. Furthermore, two or more separate channels can enable multi-channel or multi-dimensional gas chromatography. The through holes preferably have a circular cross section and can be coated with a stationary phase material or packed with a porous packing material. Importantly, uniform stationary phase coatings can be obtained and band broadening can be minimized with the circular channels. A heating or cooling element can be disposed on at least one of the lids to enable temperature programming of the column.

  16. Computational analysis of ozonation in bubble columns

    Energy Technology Data Exchange (ETDEWEB)

    Quinones-Bolanos, E. [Univ. of Guelph, School of Engineering, Guelph, Ontario (Canada)]|[Univ. de Cartagena, Facultad de Ciencias e Ingenieria, Cartagena de Indias (Colombia); Zhou, H.; Otten, L. [Univ. of Guelph, School of Engineering, Guelph, Ontario (Canada)]. E-mail: hzhou@uoguelph.ca

    2002-06-15

    This paper presents a new computational ozonation model based on the principle of computational fluid dynamics along with the kinetics of ozone decay and microbial inactivation to predict the performance of ozone disinfection in fine bubble columns. The model can be represented using a mixture two-phase flow model to simulate the hydrodynamics of the water flow and using two transport equations to track the concentration profiles of ozone and microorganisms along the height of the column, respectively. The applicability of this model was then demonstrated by comparing the simulated ozone concentrations with experimental measurements obtained from a pilot scale fine bubble column. One distinct advantage of this approach is that it does not require the prerequisite assumptions such as plug flow condition, perfect mixing, tanks-in-series, uniform radial or longitudinal dispersion in predicting the performance of disinfection contactors without carrying out expensive and tedious tracer studies. (author)

  17. Methylmercury production in the marine water column

    Science.gov (United States)

    Topping, G.; Davies, I. M.

    1981-03-01

    Although the biosynthesis of methylmercury in sediments is well established1, this is not necessarily the exclusive natural source of methylmercury entering the marine food chain, particularly commercial fish and shellfish species for human consumption. An examination of mercury levels in freshwater fish2, collected from a lake with a history of industrial mercury contamination, suggested that levels in fish are controlled in part by mercury in suspension and it followed that methylation should occur in the water column. Although methylmercury is present in seawater in coastal areas receiving discharges of waste containing either inorganic mercury3 or methylmercury4 there is no evidence that methylmercury is actually formed in the water column. We now present data which demonstrate that inorganic mercury can be methylated in the water column and we compare this production with that known to occur in marine sediments.

  18. Neutron camera employing row and column summations

    Science.gov (United States)

    Clonts, Lloyd G.; Diawara, Yacouba; Donahue, Jr, Cornelius; Montcalm, Christopher A.; Riedel, Richard A.; Visscher, Theodore

    2016-06-14

    For each photomultiplier tube in an Anger camera, an R.times.S array of preamplifiers is provided to detect electrons generated within the photomultiplier tube. The outputs of the preamplifiers are digitized to measure the magnitude of the signals from each preamplifier. For each photomultiplier tube, a corresponding summation circuitry including R row summation circuits and S column summation circuits numerically add the magnitudes of the signals from preamplifiers for each row and for each column to generate histograms. For a P.times.Q array of photomultiplier tubes, P.times.Q summation circuitries generate P.times.Q row histograms including R entries and P.times.Q column histograms including S entries. The total set of histograms include P.times.Q.times.(R+S) entries, which can be analyzed by a position calculation circuit to determine the locations of events (detection of a neutron).

  19. Accelerating selected columns of the density matrix computations via approximate column selection

    CERN Document Server

    Damle, Anil; Ying, Lexing

    2016-01-01

    Localized representation of the Kohn-Sham subspace plays an important role in quantum chemistry and materials science. The recently developed selected columns of the density matrix (SCDM) method [J. Chem. Theory Comput. 11, 1463, 2015] is a simple and robust procedure for finding a localized representation of a set of Kohn-Sham orbitals from an insulating system. The SCDM method allows the direct construction of a well conditioned (or even orthonormal) and localized basis for the Kohn-Sham subspace. The SCDM procedure avoids the use of an optimization procedure and does not depend on any adjustable parameters. The most computationally expensive step of the SCDM method is a column pivoted QR factorization that identifies the important columns for constructing the localized basis set. In this paper, we develop a two stage approximate column selection strategy to find the important columns at much lower computational cost. We demonstrate the effectiveness of this process using a dissociation process of a BH$_{3}...

  20. Final Report, Distillation Column Flooding Predictor

    Energy Technology Data Exchange (ETDEWEB)

    George E. Dzyacky

    2003-05-31

    The Flooding Predictor is an advanced process control strategy comprising a patented pattern-recognition methodology that identifies pre-flood patterns discovered to precede flooding events in distillation columns. The grantee holds a U.S. patent on the modeling system. The technology was validated at the Separations Research Program, The University of Texas at Austin under a grant from the U. S. Department of Energy, Inventions & Innovation Program. Distillation tower flooding occurs at abnormally high vapor and/or liquid rates. The loss in tray efficiencies is attributed to unusual behavior of liquid inventories inside the column leading to conditions of flooding of the space in between trays with liquid. Depending on the severity of the flood condition, consequences range from off spec products to equipment damage and tower shutdown. This non-intrusive pattern recognition methodology, processes signal data obtained from existing column instrumentation. Once the pattern is identified empirically, it is modeled and coded into the plant's distributed control system. The control system is programmed to briefly "unload" the tower each time the pattern appears. The unloading takes the form of a momentary reduction in column severity, e.g., decrease bottom temperature, reflux or tower throughput. Unloading the tower briefly at the pre-flood state causes long-term column operation to become significantly more stable - allowing an increase in throughput and/or product purity. The technology provides a wide range of value between optimization and flooding. When a distillation column is not running at capacity, it should be run in such a way ("pushed") that optimal product purity is achieved. Additional benefits include low implementation and maintenance costs, and a high level of console operator acceptance. The previous commercial applications experienced 98% uptime over a four-year period. Further, the technology is unique in its ability to distinguish between

  1. Retention Models on Core-Shell Columns.

    Science.gov (United States)

    Jandera, Pavel; Hájek, Tomáš; Růžičková, Marie

    2017-07-13

    A thin, active shell layer on core-shell columns provides high efficiency in HPLC at moderately high pressures. We revisited three models of mobile phase effects on retention for core-shell columns in mixed aqueous-organic mobile phases: linear solvent strength and Snyder-Soczewiński two-parameter models and a three-parameter model. For some compounds, two-parameter models show minor deviations from linearity due to neglect of possible minor retention in pure weak solvent, which is compensated for in the three-parameter model, which does not explicitly assume either the adsorption or the partition retention mechanism in normal- or reversed-phase systems. The model retention equation can be formulated as a function of solute retention factors of nonionic compounds in pure organic solvent and in pure water (or aqueous buffer) and of the volume fraction of an either aqueous or organic solvent component in a two-component mobile phase. With core-shell columns, the impervious solid core does not participate in the retention process. Hence, the thermodynamic retention factors, defined as the ratio of the mass of the analyte mass contained in the stationary phase to its mass in the mobile phase in the column, should not include the particle core volume. The values of the thermodynamic factors are lower than the retention factors determined using a convention including the inert core in the stationary phase. However, both conventions produce correct results if consistently used to predict the effects of changing mobile phase composition on retention. We compared three types of core-shell columns with C18-, phenyl-hexyl-, and biphenyl-bonded phases. The core-shell columns with phenyl-hexyl- and biphenyl-bonded ligands provided lower errors in two-parameter model predictions for alkylbenzenes, phenolic acids, and flavonoid compounds in comparison with C18-bonded ligands.

  2. Complex osteotomies vertebral column resection and decancellation.

    Science.gov (United States)

    Obeid, Ibrahim; Bourghli, Anouar; Boissière, Louis; Vital, Jean-Marc; Barrey, Cédric

    2014-07-01

    Pedicle subtraction osteotomy (PSO) is nowadays widely used to treat sagittal imbalance. Some complex malalignment cases cannot be treated by a PSO, whereas the imbalance is coronal or mixed or the sagittal imbalance is major and cannot be treated by a single PSO. The aim of this article was to review these complex situations--coronal imbalance, mixed imbalance, two-level PSO, vertebral column resection, and vertebral column decancellation, and to focus on their specificities. It wills also to evoke the utility of navigation in these complex cases.

  3. Column flotation in coal: does it make `cents?`

    Energy Technology Data Exchange (ETDEWEB)

    Laurila, M.J.

    1997-01-01

    Column flotation technology was introduced into the coal industry in 1986. The column can produce higher grade concentrates than conventional cells. This has created a niche market for columns in recovering ultrafine (-100 mesh) coal from waste streams. However, column flotation is much more expensive than froth flotation and columns can only process a maximum of 20 tons per hour per unit and consume more reagents than conventional cells. Researchers at Michigan Technological University have found that baffles along the axis of a column vastly improved performance. Today only two companies in the US participate in the column flotation market, ICF Kaiser and Deister.

  4. Soil Property Influences on Xiphinema americanum Populations as Related to Maturity of Loess-Derived Soils.

    Science.gov (United States)

    Schmitt, D P

    1973-10-01

    Field populations of Xiphinerna americanum around roots of Syringa vulgaris 'President Lincoln' were larger in Marshall silty clay loam, a medially developed loess soil, than in Monona silt loam, a minimally developed loess soil. Most X. amerieanum occurred in the top 15 cm of soil, with few below 30 cm. Maximum numbers occurred in August of both years in the Marshall soil, and in August 1969 and June 1970 in the Monona soil. Population fluctuations during the growing season were coincident with changes in soil moisture content. Although the population fluctuation pattern was the same at each depth tested, the adult-to-juvenile ratio increased in one soil while it decreased in the other. Numbers of X. americanum decreased as root weights decreased within a soil profile, but they were not correlated with root weights over all soils and depths. More X. americanum were recovered from the Marshall than from the Monona soil, but fibrous root weights were greater in the Monona soil. Survival of X. americanum in soil columns in growth chamber experiments was better in the Marshall than in the Monona soil. Movement and survival were different in identically textured Monona A and B horizon soils. Factors related to the ion exchange sites may affect X. americanum.

  5. Effects of Soil properties on phosphorus subsurface migration in sandy soils

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ming-Kui

    2008-01-01

    The soil factors influencing the potential migration of dissolved and particulate phosphorus (P) from structurallyweak sandy subsoils were evaluated by means of soil column leaching experiments.Soil colloids were extracted from two types of soils to make the colloid-bound forms of P solution.Eight sandy soils with diverse properties were collected for packing soil columns.The effects of influent solutions varying in concentrations of colloids,P,and electrolyte,on the transport of P and quality of leachates were characterized.P migration in the soils was soil property-dependent.High soil electrical conductivity values retarded the mobility of colloids and transportability of colloid-associated P (particulate P).Soil electrical conductivity was negatively correlated with colloids and reactive particulate P (RPP) concentrations in the leachates,whereas,the total reactive P (TRP) and dissolved reactive P (DRP) concentrations in the leachates were mainly controlled by the P adsorption capacity and the P levels in the subsoil.The reactive particulate P in the leachates was positively correlated with the colloidal concentration.Increased colloidal concentration in the influent could significantly increase the colloidal concentration in the leachates.Elevated P concentration in the influent had little effect on P recovery in the leachates,but it resulted in significant increases in the absolute P concentration in the leachates.

  6. Soil friability

    DEFF Research Database (Denmark)

    Munkholm, Lars Juhl

    2011-01-01

    has been found but it is not possible to identify a specific lower critical level of organic matter across soil types. Sustainable management of soil requires continuous and adequate inputs of organic matter to sustain or improve soil friability. Intensive tillage and traffic in unfavorable conditions...... for optimal friability. There is a strong need to get more detailed knowledge about effects of soil water content on soil friability and especially to be able to quantify the least limiting water range for soil friability and therefore soil tillage. A strong relationship between organic matter and friability...

  7. The industrial practice and development of flotation column in China

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jiongtian; Zhang Shuangquan [China Univ. of Mining and Technology, Xuzhou (China). Dept. of Energy Utilization and Chemical Engineering

    1997-12-31

    This paper reviewed the developing course of the flotation column since the 1960`s in China. Based on the practical data from several coal preparation plants, two types of flotation columns (the pressure aerated column and the jetting-cyclone column) were compared by their operation, performance and the reasons why they succeeded in the coal industry in China. The paper points out that the flotation column has come into commercial use and has good application prospects in China.

  8. Reducing axial mixing in flotation columns

    Energy Technology Data Exchange (ETDEWEB)

    Al Taweel, A.M.; Ramadan, A.M. [Technical Univ. of Nova Scotia, Halifax (Canada). Chemical Engineering Dept.; Moharam, M.R.; Hassan, T.A. [Al Azhar Univ., Cairo (Egypt); El Mofty, S.M. [Cairo Univ., Giza (Egypt)

    1995-10-01

    The axial mixing characteristics of a pilot-scale flotation column were investigated with the objective of identifying means to mitigate the extent of axial mixing that adversely affects its grade/recovery performance. A wide range of design and operating conditions wa investigated and the experimental results, obtained using the dynamic response method, were analyzed using three axial mixing models. The dynamic response of the column can best be described using the axial dispersion model. The results obtained suggest that the value of the axial dispersion coefficient, E{sub L}, can be significantly reduced by judicial selection of hydrodynamic conditions and/or the use of column inserts that suppress the onset of hydrodynamic instabilities inherent to the operation of conventional flotation columns. Up to 40% reduction in the value of E{sub L} was thus obtained by using spargers that produce more uniform bubble sizes, while up to 30% reductions were obtained by controlling the residual frother concentration. 33 refs., 7 figs.

  9. On Row Rank Equal Column Rank

    Science.gov (United States)

    Khalili, Parviz

    2009-01-01

    We will prove a well-known theorem in Linear Algebra, that is, for any "m x n" matrix the dimension of row space and column space are the same. The proof is based on the subject of "elementary matrices" and "reduced row-echelon" form of a matrix.

  10. Robust Geometric Control of a Distillation Column

    DEFF Research Database (Denmark)

    Kymmel, Mogens; Andersen, Henrik Weisberg

    1987-01-01

    A frequency domain method, which makes it possible to adjust multivariable controllers with respect to both nominal performance and robustness, is presented. The basic idea in the approach is that the designer assigns objectives such as steady-state tracking, maximum resonance peaks, bandwidth, m...... is used to examine and improve geometric control of a binary distillation column....

  11. The Special Column of Primate Behavior

    Institute of Scientific and Technical Information of China (English)

    Baoguo LI; Guest Editor

    2010-01-01

    @@ It is a long-term policy to publish SPECIAL COLUMNs in Current Zoology, and I am delighted that the journal is publishing this special colunm devoted to the topic of Primate Behavior. The eight papers in this seetion present significant new data and synthesize these findings with existing information on sexual selection of human-being and behaviors of living primates.

  12. Thermal Analysis of LANL Ion Exchange Column

    Energy Technology Data Exchange (ETDEWEB)

    Laurinat, J.E.

    1999-06-16

    This document reports results from an ion exchange column heat transfer analysis requested by Los Alamos National Laboratory (LANL). The object of the analysis is to demonstrate that the decay heat from the Pu-238 will not cause resin bed temperatures to increase to a level where the resin significantly degrades.

  13. "Dry-column" chromatography of plant pigments

    Science.gov (United States)

    Woeller, F. H.; Lehwalt, M. F.; Oyama, V. I.

    1973-01-01

    Separation of plant pigments which can be accomplished on thin-layer silica plates with mixture of petroleum ether, halocarbon, acetone, and polar solvent can be readily translated into dry-column technique that yields reproducible chromatograms after elution in fashion of liquid chromatography with fluorimeter as detector. Best solvent system was found to be mixture of petroleum ether, dichloromethane, acetone, and ethyl acetate.

  14. WATER COLUMN DATA AND SPECTRAL IRRADIANCE MODEL

    Science.gov (United States)

    Water samples collected monthly, for 18 months, from six sites in the Laguna Madre were analyzed to identify and quantify phytopigments using High Performance Liquid Chromatography (HPLC). In addition, water column pigment and nutrient data were acquired at 12 stations in Upper ...

  15. Flexural buckling of fire exposed aluminium columns

    NARCIS (Netherlands)

    Maljaars, J.; Twilt, L.; Soetens, F.

    2009-01-01

    In order to study buckling of fire exposed aluminium columns, a finite element model is developed. The results of this model are verified with experiments. Based on a parametric study with the finite element model, it is concluded that the simple calculation model for flexural buckling of fire expos

  16. Contexts for Column Addition and Subtraction

    Science.gov (United States)

    Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen

    2011-01-01

    In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by…

  17. Contexts for Column Addition and Subtraction

    Science.gov (United States)

    Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen

    2011-01-01

    In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by…

  18. Investigating Controls on Denitrification Rates During Managed Aquifer Recharge: Linking Field and Laboratory Column Experiments

    Science.gov (United States)

    Gorski, G.; Beganskas, S.; Weir, W. B.; Karim, P.; Saltikov, C.; Hernandez, J.; Fisher, A. T.

    2016-12-01

    We present initial results from a series of laboratory column experiments aimed at elucidating the underlying controls on water quality improvement during managed aquifer recharge (MAR). During field infiltration experiments, we have observed decreases in nitrate (NO3-) concentrations of up to 20% at infiltration rates as high as 15 m/day in the presence of woodchips, but no nitrate removal in the absence of woodchips at slower infiltration rates. These results suggest that the extent of nitrate removal is strongly influenced by the rate of infiltrating water and the presence of a carbon amendment in the form of redwood chips or biochar, which facilitates microbial processing. We probe these relationships at a finer spatial scale with laboratory flow-through column experiments. The columns are constructed as analogues to field experiments, with fluid and substrate sampled directly from field sites. Each day, we sample fluid along the length of the column during experiments to analyze for nitrate, dissolved oxygen, and dissolved organic carbon, in order to track changes in redox conditions and biogeochemistry. The experimental setup allows us to finely control the fluid flow rate and fluid residence time, in order to quantify the relationship between nitrate removal rate and total infiltration rate over a wider range of conditions than is possible during field studies. To determine how the addition of reactive media might increase nitrate removal rates, we conduct side-by-side comparisons of native soil and soil amended with a carbon source. We also analyze changes in nitrate isotope enrichment and microbial ecology to gain a better understanding of the microbial processes and communities responsible for nitrate removal. These field and lab experiments are helping us learn how fluid flow rate, soil type, and availability of carbon sources influences nitrate removal during infiltration for MAR, which can improve the quality of MAR water resources.

  19. Shear wave velocity-based evaluation and design of stone column improved ground for liquefaction mitigation

    Institute of Scientific and Technical Information of China (English)

    Zhou Yanguo; Sun Zhengbo; Chen Jie; Chen Yunmin; Chen Renpeng

    2017-01-01

    The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice.In this paper,a shear wave velocity-based approach is proposed based on the well-defined correlations of liquefaction resistance (CRR)-shear wave velocity (Vs)-void ratio (e) of sandy soils,and the values of parameters in this approach are recommended for preliminary design purpose when site specific values are not available.The detailed procedures of pre-and post-improvement liquefaction evaluations and stone column design are given.According to this approach,the required level of ground improvement will be met once the target Vs of soil is raised high enough (i.e.,no less than the critical velocity) to resist the given earthquake loading according to the CRR-Vs relationship,and then this requirement is transferred to the control of target void ratio (i.e.,the critical e) according to the Vs-e relationship.As this approach relies on the densification of the surrounding soil instead of the whole improved ground and is conservative by nature,specific considerations of the densification mechanism and effect are given,and the effects of drainage and reinforcement of stone columns are also discussed.A case study of a thermal power plant in Indonesia is introduced,where the effectiveness of stone column improved ground was evaluated by the proposed Vs-based method and compared with the SPT-based evaluation.This improved ground performed well and experienced no liquefaction during subsequent strong earthquakes.

  20. Shear wave velocity-based evaluation and design of stone column improved ground for liquefaction mitigation

    Science.gov (United States)

    Zhou, Yanguo; Sun, Zhengbo; Chen, Jie; Chen, Yunmin; Chen, Renpeng

    2017-04-01

    The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice. In this paper, a shear wave velocity-based approach is proposed based on the well-defined correlations of liquefaction resistance (CRR)-shear wave velocity ( V s)-void ratio ( e) of sandy soils, and the values of parameters in this approach are recommended for preliminary design purpose when site specific values are not available. The detailed procedures of pre- and post-improvement liquefaction evaluations and stone column design are given. According to this approach, the required level of ground improvement will be met once the target V s of soil is raised high enough (i.e., no less than the critical velocity) to resist the given earthquake loading according to the CRR- V s relationship, and then this requirement is transferred to the control of target void ratio (i.e., the critical e) according to the V s- e relationship. As this approach relies on the densification of the surrounding soil instead of the whole improved ground and is conservative by nature, specific considerations of the densification mechanism and effect are given, and the effects of drainage and reinforcement of stone columns are also discussed. A case study of a thermal power plant in Indonesia is introduced, where the effectiveness of stone column improved ground was evaluated by the proposed V s-based method and compared with the SPT-based evaluation. This improved ground performed well and experienced no liquefaction during subsequent strong earthquakes.

  1. Remediation of PCE-contaminated aquifer by an in situ two-layer biobarrier: laboratory batch and column studies.

    Science.gov (United States)

    Kao, C M; Chen, S C; Wang, J Y; Chen, Y L; Lee, S Z

    2003-01-01

    The industrial solvent tetrachloroethylene (PCE) is among the most ubiquitous chlorinated compounds found in groundwater contamination. The objective of this study was to develop an in situ two-layer biobarrier system consisting of an organic-releasing material layer followed by an oxygen-releasing material layer. The organic-releasing material, which contained sludge cakes from a domestic wastewater treatment plant, is able to release biodegradable organics continuously. The oxygen-releasing material, which contained calcium peroxide, is able to release oxygen continuously upon contact with water. The first organic-releasing material layer was to supply organics (primary substrates) to reductively dechlorinate PCE in situ. The second oxygen-releasing material layer was to release oxygen to aerobic biodegrade or cometabolize PCE degradation byproducts from the first anaerobic layer. Batch experiments were conducted to design and identify the components of the organic and oxygen-releasing materials, and evaluate the organic substrate (presented as chemical oxygen demand (COD) equivalent) and oxygen release rates from the organic-releasing material and oxygen-releasing materials, respectively. The observed oxygen and COD release rates were approximately 0.0368 and 0.0416 mg/d/g of material, respectively. A laboratory-scale column experiment was then conducted to evaluate the feasibility of this proposed system for the bioremediation of PCE-contaminated groundwater. This system was performed using a series of continuous-flow glass columns including a soil column, an organic-releasing material column, two consecutive soil columns, and an oxygen-releasing material column, followed by two other consecutive soil columns. Anaerobic acclimated sludges were inoculated in the first four columns, and aerobic acclimated sludges were inoculated in the last three columns to provide microbial consortia for contaminant biodegradation. Simulated PCE-contaminated groundwater with a

  2. Predicting saturated hydraulic conductivity using soil morphological properties

    Directory of Open Access Journals (Sweden)

    Gülay Karahan

    2016-01-01

    Full Text Available Many studies have been conducted to predict soil saturated hydraulic conductivity (Ks by parametric soil properties such as bulk density and particle-size distribution. Although soil morphological properties have a strong effect on Ks, studies predicting Ks by soil morphological properties such as type, size, and strength of soil structure; type, orientation and quantity of soil pores and roots and consistency are rare. This study aimed at evaluating soil morphological properties to predict Ks. Undisturbed soil samples (15 cm length and 8.0 cm id. were collected from topsoil (0-15 cm and subsoil (15-30 cm (120 samples with a tractor operated soil sampler at sixty randomly selected sampling sites on a paddy field and an adjecent grassland in Central Anatolia (Cankırı, Turkey. Synchronized disturbed soil samples were taken from the same sampling sites and sampling depths for basic soil analyses. Saturated hydraulic conductivity was measured on the soil columns using a constant-head permeameter. Following the Ks measurements, the upper part of soil columns were covered to prevent evaporation and colums were left to drain in the laboratory. When the water flow through the column was stopped, a subsample were taken for bulk density and then soil columns were disturbed for describing the soil morphological properties. In addition, soil texture, bulk density, pH, field capacity, wilting point, cation exchange capacity, specific surface area, aggregate stability, organic matter, and calcium carbonate were measured on the synchronized disturbed soil samples. The data were divided into training (80 data values and validation (40 data values sets. Measured values of Ks ranged from 0.0036 to 2.14 cmh-1 with a mean of 0.86 cmh-1. The Ks was predicted from the soil morphological and parametric properties by stepwise multiple linear regression analysis. Soil structure class, stickiness, pore-size, root-size, and pore-quantity contributed to the Ks prediction

  3. Protocol for evaluating biokinetics and attainable end-points of polycyclic aromatic hydrocarbons in soil treatment

    Energy Technology Data Exchange (ETDEWEB)

    Tabak, H.H. [Environmental Protection Agency, Cincinnati, OH (United States); Govind, R.; Fu, C.; Gao, C. [Univ. of Cincinnati, OH (United States)

    1995-12-31

    A systematic, multi-level protocol was developed for evaluating bioavailability (sorption/desorption equilibria and kinetics), contaminant and oxygen diffusion limitations, and biodegradation kinetics of organic pollutants in compacted soil systems. The approach used soil microcosms and three types of respirometric bioreactors: soil slurry, wafer, and column. Representative experimental data is presented and, where applicable, compared to model fits.

  4. The SMAP level 4 surface and root zone soil moisture data assimilation product

    Science.gov (United States)

    The NASA Soil Moisture Active Passive (SMAP) mission is scheduled for launch in January 2015 and will provide L-band radar and radiometer observations that are sensitive to surface soil moisture (in the top few centimeters of the soil column). For several of the key applications targeted by SMAP, ho...

  5. Leaching of Added Selenium in Soils Low in Native Selenium

    DEFF Research Database (Denmark)

    Nielsen, Gunnar Gissel; Hamdy, A. A.

    1977-01-01

    A soil column experiment was performed to evaluate the influence of organic matter and lime on the leaching and distribution of added selenite. 75Se-labeled Na2SeO3 was added to water-saturated soil columns with a diameter of 4.25 cm and a length of 16-20 cm. Leaching started immediately, one l...... water being added per column during the course of 1 wk. Most of the selenite did not move through the soil, and only a few per cent were found in the leaching water. Leaching was greatest in sandy soil. It was increased by the addition of lime, but decreased by addition of organic matter. Most...

  6. Composite support column assembly for offshore drilling and production platforms

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, R.H.

    1989-04-18

    This patent describes a support column assembly for an offshore drilling and/or production comprising: means for anchoring the column assembly on the seabed; an elongated cylindrical support column including at least one generally cylindrical column member having a cylindrical wall formed of a composite of elongated filaments of at least one of carbon and boron bonded in a resin matrix, the support column including a plurality of the column members coupled end to end by coupling means at opposite ends of the column members, the coupling means including a plurality of radially project pins for coupling the composite wall to a coupling member interposed between the column members, respectively; and means for connecting the column to a platform for transmitting platform loads between the platform and the anchor means.

  7. Soil properties, soil functions and soil security

    Science.gov (United States)

    Poggio, Laura; Gimona, Alessandro

    2017-04-01

    Soil plays a crucial role in the ecosystem functioning such as food production, capture and storage of water, carbon and nutrients and in the realisation of a number of UN Sustainable Developments Goals. In this work we present an approach to spatially and jointly assess the multiple contributions of soil to the delivery of ecosystem services within multiple land-use system. We focussed on the modelling of the impact of soil on sediment retention, carbon storage, storing and filtering of nutrients, habitat for soil organisms and water regulation, taking into account examples of land use and climate scenarios. Simplified models were used for the single components. Spatialised Bayesian Belief networks were used for the jointly assessment and mapping of soil contribution to multiple land use and ecosystem services. We integrated continuous 3D soil information derived from digital soil mapping approaches covering the whole of mainland Scotland, excluding the Northern Islands. Uncertainty was accounted for and propagated across the whole process. The Scottish test case highlights the differences in roles between mineral and organic soils and provides an example of integrated study assessing the contributions of soil. The results show the importance of the multi-functional analysis of the contribution of soils to the ecosystem service delivery and UN SDGs.

  8. Single application of Sewage Sludge to an Alluvial Agricultural Soil - impacts on Soil Quality

    Science.gov (United States)

    Suhadolc, M.; Graham, D. B.; Hagn, A.; Doerfler, U.; Schloter, M.; Schroll, R.; Munch, J. C.; Lobnik, F.

    2009-04-01

    Limited information exists on the effects of sewage sludge on soil quality with regard to their ability to maintain soil functions. We studied effects of sewage sludge amendment on soil chemical properties, microbial community structure and microbial degradation of the herbicide glyphosate. Three months soil column leaching experiment has been conducted using alluvial soils (Eutric Fluvisol) with no prior history of sludge application. The soil was loamy with pH 7,4 and organic matter content of 3,5%. Soil material in the upper 2 cm of columns was mixed with dehydrated sewage sludge which was applied in amounts corresponding to the standards governing the use of sewage sludge for agricultural land. Sludge did increase some nutrients (total N, NH4+, available P and K, organic carbon) and some heavy metals contents (Zn, Cu, Pb) in soil. However, upper limits for heavy metals in agricultural soils were not exceeded. Results of heavy metal availability in soil determined by sequential extraction will be also presented. Restriction fragment length polymorphism (RFLP) analyses of 16s/18s rDNA, using universal fungal and bacterial primers, revealed clear shifts in bacterial and fungal community structure in the upper 2 cm of soils after amendment. Fungal fingerprints showed greater short term effects of sewage sludge, whereas sewage sludge seems to have prolonged effects on soil bacteria. Furthermore, sewage sludge amendment significantly increased glyphosate degradation from 21.6±1% to 33.6±1% over a 2 months period. The most probable reasons for shifts in microbial community structure and increased degradation of glyphosate are beneficial alterations to the physical-chemical characteristics of the soil. Negative effects of potentially toxic substances present in the sewage sludge on soil microbial community functioning were not observed with the methods used in our study.

  9. Passive Gamma-Ray Emission for Soil-Disturbance Detection

    Science.gov (United States)

    2016-08-01

    the degree of compaction of surrounding soils. It can serve as a physically based terrain-surface indicator of changing pat - terns of human–terrain...dynamics causing spatiotemporal change in soil temperature, and heat flux outside of normal diurnal pat - terns. It would be advantageous to be able...explains the green and brown sample clusters and agrees with column 4, soil type, the green cluster being the treatments (samples) with the South Bin

  10. Do column frits contribute to the on-column, flow-induced degradation of macromolecules?

    Science.gov (United States)

    Striegel, André M

    2014-09-12

    Flow-induced, on-column degradation is a major hindrance to the accurate characterization of ultra-high molar mass macromolecules and colloids. This degradation is a direct result of the large shear rates which are generated within the column, which cause chain scission to occur both in the interstitial medium and, it has been postulated, at the packing particle pore boundary. An additional putative source of degradation has been the column frits, though little experimental evidence exists to either support or refute this claim. To this effect, the present experiments examine the role of the frits in the degradation of high molar mass macromolecules. Two narrow dispersity polystyrene standards, the molar mass of which differs by a factor of two, were analyzed on three different size-exclusion chromatography (SEC) columns, each with frits of different pore size, at various flow rates. In the smallest pore size column, which also contained the smallest frits and which was packed with the smallest diameter particles, the larger standard was forced to degrade by increasing the flow rate of the mobile phase. During the course of the latter portion of the study, the inlet and the outlet frits were removed from the column, in stepwise fashion. It was concluded that neither frit played any appreciable role in the degradation. Results of our studies were applied to explain previously observed degradation in ultra-high pressure liquid chromatography of polymers. The general conclusion arrived at herein is that the column frits are likely to have a secondary role (as compared to interstitial and pore boundary stresses), or no role at all, in polymer degradation for cases where the frit radius is larger than or equal to the hydraulic radius rcof the column.

  11. Effect of Fluctuating Temperatures on Forest Soil Nitrogen Minerealization

    Institute of Scientific and Technical Information of China (English)

    LIAOLIPING; P.INESON

    1997-01-01

    Nitrogen mineralization in forest soil wa studied in laboratory by incubating undisturbed soil cores enclosed within PVC columns at different temperatures to compare the effect of flucttuating temperature with that of constant temperaature,and to find out whether soil nitrification shows linearity over time .The results showed that there was no significant difference between soil nitrification at fluctuating temperature and that at constant temperature,and suggested that it must be careful to make the conclusion that soil nitrification has linearity over time.

  12. Microbial Life in a Winogradsky Column: From Lab Course to Diverse Research Experience

    Directory of Open Access Journals (Sweden)

    Samantha T. Parks

    2015-02-01

    Full Text Available Many traditional lab courses include both standard and inquiry-based experiments, yet lack cooperative and authentic lab experiences.  Such experiences are important for microbiology students and burgeoning researchers.  In a novel lab environment, students constructed Winogradsky columns using common soil and water sources.  During initial column incubation, students learned methods for identification of microbial isolates including staining, microscopy, biochemistry and 16S-rRNA sequencing.  Concurrently, students challenged their columns via varied substrates and contaminants including enrichment with nitro-compounds, hydrocarbons, acids and other environmental stressors.  Students were encouraged to use both basic and more advanced identification methods to study the effect of such challenges within their columns.  The students were required to maintain lab notebooks and attend weekly lab meetings, which were designed to share progress and facilitate experimentation among their lab-mates.  At the end of the semester, students gathered to present their data and conclusions.  By engaging in weekly meetings and a final conference, students were able to construct a snapshot of the microbial diversity, including phylogeny and metabolism, in the soil and water used to construct the Winogradsky columns.  By using a common source, students were able to observe an array of diversity within individual columns and extrapolate towards the tremendous microbial diversity in the initial soil and water samples.  Equally important to the data obtained, the students engaged in a collaborative effort through discussion, trouble-shooting, weekly meetings and the summative conference.  Such efforts enabled students to participate in an authentic research experience within a traditional undergraduate laboratory course. Editor's Note:The ASM advocates that students must successfully demonstrate the ability to explain and practice safe laboratory

  13. Separation of Oil from Wastewater by Column Flotation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new type of device, a dissolved-air flotation column, was developed for separation of oily wastewater.The unique design idea of the dissolved-air flotation column is the combined use of dissolved-air flotation and column flotation.The dissolved air release occurred within the column separation system.As a potential application the column was investigated for its performance in separating emulsified oil droplets in oily wastewater.A high separation efficiency was obtained in a series of tests.The aeration performance of the bubble generator used in the dissolved-air flotation column was also studied in particular.

  14. Synchronized oscillation in a modular neural network composed of columns

    Institute of Scientific and Technical Information of China (English)

    LI; Su; QI; Xianglin; HU; Hong; WANG; Yunjiu

    2005-01-01

    The columnar organization is a ubiquitous feature in the cerebral cortex. In this study, a neural network model simulating the cortical columns has been constructed. When fed with random pulse input with constant rate, a column generates synchronized oscillations, with a frequency varying from 3 to 43 Hz depending on parameter values. The behavior of the model under periodic stimulation was studied and the input-output relationship was non-linear. When identical columns were sparsely interconnected, the column oscillator could be locked in synchrony. In a network composed of heterogeneous columns, the columns were organized by intrinsic properties and formed partially synchronized assemblies.

  15. Sorption and transport of atrazine in an agricultural soil

    Science.gov (United States)

    Hakan Akyol, Nihat

    2014-05-01

    Sorption and transport of atrazine in an agricultural soil Atrazine is one of the most commonly used herbicides in large quantity worldwide. The objective of this study was to perform some batch and column experiments to examine the transport of atrazine in an agricultural soil from Turkey. Batch experiments indicated that sorption isotherm was nonlinear with a freundlich isotherm over a range of concentration (0.2-10 mg/L) examined. Column experiments showed that transport of atrazine in the soil was moderately retarded compared to non-reactive tracer (R = 2.9-4.0). The degree of retardation decreased with increasing atrazine concentration and residance time had negligable impact on degree of sorption. Flow interruption tests in the column experiments indicated that the rate-limited desorption of atrazine mainly controlled the non-ideal transport of atrazine due to the presence of organic matter fraction (0.83 %) in the soil. Sorption and desorption behavior of atrazine in such soils could have important impacts for risk assessment of atrazine-contaminated soil and should be taken into account in the regulation, management, and remediation of atrazine-contaminated sites. Keywords: Atrazine, Agricultural soil, Batch, Column, Desorption, Rate-limited desorption, Sorption, Transport.

  16. Operation of a Batch Stripping Distillation Column

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A stripping batch distillation column is preferred when the amount of the light component in the feed is small and the products are to be recovered at high purity. The operation modes of a batch stripping are believed to be the same as those of a rectifier. However, the control system of a stripper is different. In this paper, we explore three different control methods with Hysys (Hyprotech Ltd. 1997) for a batch stripper. The main difference is the control scheme for reboiler liquid level: (a) controlled by reflux flow; (b) controlled by reboiler heat duty; (c) controlled by bottom product flow. The main characteristics of operating a batch stripper with different control scheme are presented in this paper. Guidelines are provided for the startup of a batch stripper, the effects of somecontrol tuning parameters on the column performance are discussed.

  17. The Dissipative Column: A New Hysteretic Damper

    Directory of Open Access Journals (Sweden)

    Bruno Palazzo

    2015-02-01

    Full Text Available A new replaceable hysteretic damper to better control seismic building damage, consisting of two or more adjacent steel vertical elements connected to each other with continuous mild/low strength steel shear links, is proposed and investigated in this paper. New Dampers, called Dissipative Columns (DC, continuously linked with X-shaped steel plates, provide additional stiffness and damping to a lateral system by using a basic and minimally invasive construction element: the column. Working in a way similar to coupled shear walls, the proposed element behavior is theoretically analyzed at linear and non-linear ranges. In fact, considering different restrained cases, a parametric analysis is developed in order both to evaluate the effect of the main geometrical and structural parameters and to provide the design capacity curves of this new damper. The DC can be considered a new damping device, easy to install in new as well as existing buildings in order to protect them from seismic damage.

  18. Pressure drop in CIM disk monolithic columns.

    Science.gov (United States)

    Mihelic, Igor; Nemec, Damjan; Podgornik, Ales; Koloini, Tine

    2005-02-11

    Pressure drop analysis in commercial CIM disk monolithic columns is presented. Experimental measurements of pressure drop are compared to hydrodynamic models usually employed for prediction of pressure drop in packed beds, e.g. free surface model and capillary model applying hydraulic radius concept. However, the comparison between pressure drop in monolith and adequate packed bed give unexpected results. Pressure drop in a CIM disk monolithic column is approximately 50% lower than in an adequate packed bed of spheres having the same hydraulic radius as CIM disk monolith; meaning they both have the same porosity and the same specific surface area. This phenomenon seems to be a consequence of the monolithic porous structure which is quite different in terms of the pore size distribution and parallel pore nonuniformity compared to the one in conventional packed beds. The number of self-similar levels for the CIM monoliths was estimated to be between 1.03 and 2.75.

  19. Modeling of Crystalline Silicotitanate Ion Exchange Columns

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.D.

    1999-03-09

    Non-elutable ion exchange is being considered as a potential replacement for the In-Tank Precipitation process for removing cesium from Savannah River Site (SRS) radioactive waste. Crystalline silicotitanate (CST) particles are the reference ion exchange medium for the process. A major factor in the construction cost of this process is the size of the ion exchange column required to meet product specifications for decontaminated waste. To validate SRS column sizing calculations, SRS subcontracted two reknowned experts in this field to perform similar calculations: Professor R. G. Anthony, Department of Chemical Engineering, Texas A&038;M University, and Professor S. W. Wang, Department of Chemical Engineering, Purdue University. The appendices of this document contain reports from the two subcontractors. Definition of the design problem came through several meetings and conference calls between the participants and SRS personnel over the past few months. This document summarizes the problem definition and results from the two reports.

  20. Water Column Variability in Coastal Regions

    Science.gov (United States)

    2016-06-07

    offshore waters of energy, mass, and biota. OBJECTIVES Our objective is to determine the processes that cause water column variations in coastal regions...meteorological conditions (solar radiation, wind velocity, and heat fluxes), (iv) tidal mixing, stratification, water mass variations, (v) runoff from land...air-sea gas exchange and biological activity in these offshore waters. Two papers are being submitted to Limnology and Oceanography on the annual

  1. COLLISIONS OF ROAD VEHICLES WITH BRIDGE COLUMNS

    OpenAIRE

    2015-01-01

    As speed limits and traffic on city roads continue to increase, collisions between road vehicles and bridge columns are becoming more common. Current regulations analyze collision with one major simplification: replacing dynamic action with the equivalent static force. In the present paper, we develop a numerical model of a typical Croatian overpass and loaded it with an equivalent static load according to the EN1991-7 and ASSHTO LRFD provisions, analyzing the differences in overpass behavior...

  2. Using Dividing Wall Columns (DWC) in LNG Production: deviding wall column, double dividing wall column, prefractionator arrangement, Petlyuk column, NGL recovery, distillation

    OpenAIRE

    Ashrafian, Roohollah

    2014-01-01

    The Dividing Wall Columns (DWC) distillation has attracted growing interest for fractionation of multicomponent mixture due to reduction of energy consumption, auxiliary equipment and space within fractionation process. Recent developments of the process show considerable energy saving, up to 30%-40%, compared to conventional fractionation schemes. The objective of this thesis is to introduce DWC configurations, governing equations and applications in LNG and gas processing as well as explana...

  3. [Cervical vertebral column--anatomy, fractures, treatment].

    Science.gov (United States)

    Kłosiński, Michał; Sienkiewicz-Zawilińska, Justyna; Lipski, Marcin; Zawiliński, Jarosław; Matyja, Andrzej; Walocha, Jerzy

    2009-01-01

    The paper deals with anatomy of human cervical spine. It shows close relation between knowledge on the normal structure and methods of treatment of different kinds of spine injuries. It describes detailed anatomy and mechanical features of cervical vertebral column, including the structure of distinct vertebrae, their joints and arrangement of muscles. It reviews also historical methods of treatment of fractures in this region considering current methods.

  4. SVD row or column symmetric matrix

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new architecture for row or column symmetric matrix called extended matrix is defined, and a precise correspondence of the singular values and singular vectors between the extended matrix and its original (namely, the mother matrix) is derived. As an illustration of potential, we show that, for a class of extended matrices, the singular value decomposition using the mother matrix rather than the extended matrix per se can save the CPU time and memory without loss of numerical precision.

  5. Plant practices in fine coal column flotation

    Energy Technology Data Exchange (ETDEWEB)

    Davis, V.L. Jr.; Bethell, P.J.; Stanley, F.L. [Pittston Coal Management Co., Lebanon, VA (United States); Luttrell, G.H. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States). Dept. of Mining and Minerals Engineering

    1995-10-01

    Five 3 m (10 ft) diameter Microcel{trademark} flotation columns were installed at Clinchfield Coal Company`s Middle Fork preparation facility in order to reduce product ash and increase recovery and plant capacity. The Middle Fork facility is utilized for the recovery of fine coal from a feed stream that consists primarily of 1.5 mm x 0 material. The columns replaced conventional flotation cells for the treatment of the minus 150 {micro}m fraction while spirals are used to upgrade the plus 150 {micro}m material in the plant feed. The addition of the column flotation circuit resulted in an increase in plant capacity in excess of 20 percent while reducing the flotation product ash content by approximately 7 percentage points. Flotation circuit combustible recovery wa increased by 17 percentage points. This paper discusses circuit design, commissioning, and sparging system design. Circuit instrumentation, level control, reagent system control, performance comparisons with conventional flotation, and general operating procedures are also discussed.

  6. Seepage characteristics of collapse column fillings

    Institute of Scientific and Technical Information of China (English)

    Zhang Boyang; Bai Haibo; Zhang Kai

    2016-01-01

    With concealment and hysteresis, water-inrush from Karst collapse column has become an important security hazard of lower group coal mining in North China. Based on the MTS815.02 seepage test system, we analyzed the impact of consolidation pressure, initial moisture content and confining pressure on the permeability of fillings in order to study the seepage characteristics of collapse column fillings. The results show that:(1) The permeability of collapse column fillings is of the order of 10?16–10?15 magni-tude and decreases with an increase in consolidation pressure and decrease in initial moisture content. (2) The essence of filling seepage law change is the change in porosity, and a power function relationship exists between the permeability ratio and porosity ratio. (3) With increasing confining pressure, the per-meability of fillings decreases. However, under low confining pressure (1.2–4 MPa), the change of confin-ing pressure has no obvious influence on the permeability.

  7. SPEEDUP{trademark} ion exchange column model

    Energy Technology Data Exchange (ETDEWEB)

    Hang, T.

    2000-03-06

    A transient model to describe the process of loading a solute onto the granular fixed bed in an ion exchange (IX) column has been developed using the SpeedUp{trademark} software package. SpeedUp offers the advantage of smooth integration into other existing SpeedUp flowsheet models. The mathematical algorithm of a porous particle diffusion model was adopted to account for convection, axial dispersion, film mass transfer, and pore diffusion. The method of orthogonal collocation on finite elements was employed to solve the governing transport equations. The model allows the use of a non-linear Langmuir isotherm based on an effective binary ionic exchange process. The SpeedUp column model was tested by comparing to the analytical solutions of three transport problems from the ion exchange literature. In addition, a sample calculation of a train of three crystalline silicotitanate (CST) IX columns in series was made using both the SpeedUp model and Purdue University's VERSE-LC code. All test cases showed excellent agreement between the SpeedUp model results and the test data. The model can be readily used for SuperLig{trademark} ion exchange resins, once the experimental data are complete.

  8. Modular evolution of the Cetacean vertebral column.

    Science.gov (United States)

    Buchholtz, Emily A

    2007-01-01

    Modular theory predicts that hierarchical developmental processes generate hierarchical phenotypic units that are capable of independent modification. The vertebral column is an overtly modular structure, and its rapid phenotypic transformation in cetacean evolution provides a case study for modularity. Terrestrial mammals have five morphologically discrete vertebral series that are now known to be coincident with Hox gene expression patterns. Here, I present the hypothesis that in living Carnivora and Artiodactyla, and by inference in the terrestrial ancestors of whales, the series are themselves components of larger precaudal and caudal modular units. Column morphology in a series of fossil and living whales is used to predict the type and sequence of developmental changes responsible for modification of that ancestral pattern. Developmental innovations inferred include independent meristic additions to the precaudal column in basal archaeocetes and basilosaurids, stepwise homeotic reduction of the sacral series in protocetids, and dissociation of the caudal series into anterior tail and fluke subunits in basilosaurids. The most dramatic change was the novel association of lumbar and anterior caudal vertebrae in a module that crosses the precaudal/caudal boundary. This large unit is defined by shared patterns of vertebral morphology, count, and size in all living whales (Neoceti).

  9. Dynamics of a Tapped Granular Column

    Science.gov (United States)

    Rosato, Anthony; Blackmore, Denis; Zuo, Luo; Hao, Wu; Horntrop, David

    2015-11-01

    We consider the behavior of a column of spheres subjected to a time-dependent vertical taps. Of interest are various dynamical properties, such as the motion of its mass center, its response to taps of different intensities and forms, and the effect of system size and material properties. The interplay between diverse time and length scales are the key contributors to the column's evolving dynamics. Soft sphere discrete element simulations were conducted over a very wide parameter space to obtain a portrait of column behavior as embodied by the collective dynamics of the mass center motion. Results compared favorably with a derived reduced-order paradigm of the mass center motion (surprisingly analogous to that for a single bouncing ball on an oscillating plate) with respect to dynamical regimes and their transitions. A continuum model obtained from a system of Newtonian equations, as a locally averaged limit in the transport mode along trajectories is described, and a numerical solution protocol for a one-dimensional system is outlined. Typical trajectories and density evolution profiles are shown. We conclude with a discussion of our investigations to relate predictions of the continuum and reduced dynamical systems models with discrete simulations.

  10. Employing anatomical knowledge in vertebral column labeling

    Science.gov (United States)

    Yao, Jianhua; Summers, Ronald M.

    2009-02-01

    The spinal column constitutes the central axis of human torso and is often used by radiologists to reference the location of organs in the chest and abdomen. However, visually identifying and labeling vertebrae is not trivial and can be timeconsuming. This paper presents an approach to automatically label vertebrae based on two pieces of anatomical knowledge: one vertebra has at most two attached ribs, and ribs are attached only to thoracic vertebrae. The spinal column is first extracted by a hybrid method using the watershed algorithm, directed acyclic graph search and a four-part vertebra model. Then curved reformations in sagittal and coronal directions are computed and aggregated intensity profiles along the spinal cord are analyzed to partition the spinal column into vertebrae. After that, candidates for rib bones are detected using features such as location, orientation, shape, size and density. Then a correspondence matrix is established to match ribs and vertebrae. The last vertebra (from thoracic to lumbar) with attached ribs is identified and labeled as T12. The rest of vertebrae are labeled accordingly. The method was tested on 50 CT scans and successfully labeled 48 of them. The two failed cases were mainly due to rudimentary ribs.

  11. Behavior of high strength concrete columns under eccentric loads

    Directory of Open Access Journals (Sweden)

    Hany A. Kottb

    2015-04-01

    Full Text Available In recent decades, high strength concrete (HSC has been widely accepted by designers and contractors to be used in concrete structures, especially in high compressive stress elements. The research aims to study the behavior of high strength concrete columns under eccentric compression using experimental and analytical programs. The research is divided into two main parts; the first part is an experimental investigation for ten square columns tested at the Cairo University Concrete Research Laboratory. The main studied parameters were eccentricity of the applied load, column slenderness ratio; and ratios of longitudinal and transverse reinforcement. The second part is analytical analysis using nonlinear finite element program ANSYS11 on nineteen columns (ten tested square columns and nine rectangular section columns to study the effect of the previous parameters on the column ultimate load, mid-height displacement, and column cracking patterns. The analyzed columns revealed a good agreement with the experimental results with an average difference of 16% and 17% for column ultimate load and mid-height displacement respectively. Results showed an excellent agreement for cracking patterns. Predictions of columns capacities using the interaction diagrams based on ACI 318-08 stress block parameters indicated a safe design procedure of HSC columns under eccentric compression, with ACI 318-08 being more conservative for moderate reinforced HSC columns.

  12. Increase of In-Situ Measured Shear Wave Velocity in Sands with Displacement Pile and Stone Column Inclusions

    Directory of Open Access Journals (Sweden)

    Franciscus Xaverius Toha

    2017-04-01

    Full Text Available Seismic downhole and MASW measurements were conducted at a potentially liquefiable site, where PC piles and stone column inclusion were provided to remediate the foundation soil. The selected site is part of a refinery located in high seismicity zone. The seismic measurements were done prior and after the PC piles and stone columns were installed. The densification, reinforcing, and dissipation contribution to the overall mitigation was elaborated herein. The measurement results are essentially consistent with the most recent theoretical developments and indicate that the strengthening due to mitigation is higher than predicted.

  13. Soil formation.

    NARCIS (Netherlands)

    Breemen, van N.; Buurman, P.

    1998-01-01

    Soil Formation deals with qualitative and quantitative aspects of soil formation (or pedogenesis) and the underlying chemical, biological, and physical processes. The starting point of the text is the process - and not soil classification. Effects of weathering and new formation of minerals, mobilis

  14. Experimental Testing Of Partially Encased Composite Beam Columns

    Directory of Open Access Journals (Sweden)

    Ehab M. Hanna

    2016-01-01

    Full Text Available The past few decades have seen outstanding advances in the use of composite materials in structural applications. There can be little doubt that, within engineering circles, composites have revolutionized traditional design concepts and made possible an unparalleled range of new and exciting possibilities as viable materials for construction. In addition to the well-known advantages of composite columns, partially encased composite columns offered simplified beam-to-column connection as well as reduced or omitted shuttering thus achieved more cost effective construction. Some companies have patented these new types of partially encased composite column made of light welded steel shapes; moreover, the Canadian Institute of Steel construction CISC has recognized and codified this type of columns. In This paper, Partially Encased Composite Beam Columns is introduced; experimental studies are made on five partially encased beam columns to investigate the behavior of eccentrically loaded partially encased composite columns using different parameters.

  15. Composition Estimation in Dividing-Wall Columns Using Temperature Measurements

    OpenAIRE

    Ghadrdan, Maryam; Ivar J. Halvorsen; Skogestad, Sigurd

    2011-01-01

    In this work, we propose a method to estimate the product compositions in a distillation column section based on a combination of a number of temperature measurements from different locations in the column stages.

  16. Influence of Exogenous Lanthanum on Fertility Parameters of Red Soil and Paddy Soil

    Institute of Scientific and Technical Information of China (English)

    谢祖彬; 朱建国; 褚海燕; 曾青; 张雅丽; 曹志洪

    2001-01-01

    The effects of exogenous La on the fertility parameters such as cation exchange capacity (CEC), exchangeable basic cations, and exchangeable acidity in red soil and paddy soil were studied with soil column simulation. The results show that with increasing amount of the added La, the proportion of exchangeable La in soils increases and there is more exchangeable La in red soil than in paddy soil. When the concentration of La is more than 600 mg*kg-1, the proportion of exchangeable La almost remains constant. When the concentration of La is less than 1200 mg*kg-1, there is no significant effect on CEC in red soil. But when the concentration of La is more than 1200 mg*kg-1, it has significant effect on CEC in paddy soil. The application of La resulted in increasing exchangeable aluminum, Ca and Mg in soil solution, and decreasing exchangeable Ca and Mg retained in soils. But when the concentration of La is less than 150 mg*kg-1, it has no significant influence on CEC, exchangeable Ca and Mg, and exchangeable acidity in red soil and paddy soil.

  17. Water and heat transport in hilly red soil of southern China: I. Experiment and analysis

    Institute of Scientific and Technical Information of China (English)

    LU Jun; HUANG Zhi-zhen; HAN Xiao-fei

    2005-01-01

    Studies on coupled transfer of soil moisture and heat have been widely carried out for decades. However, little work has been done on red soils, widespread in southern China. The simultaneous transfer of soil moisture and heat depends on soil physical properties and the climate conditions. Red soil is heavy clay and high content of free iron and aluminum oxide. The climate conditions are characterized by the clear four seasons and the serious seasonal drought. The great annual and diurnal air temperature differences result in significant fluctuation in soil temperature in top layer. The closed and evaporating columns experiments with red soil were conducted to simulate the coupled transfer of soil water and heat under the overlaying and opening fields' conditions, and to analyze the effects of soil temperature gradient on the water transfer and the effects of initial soil water contents on the transfer of soil water and heat. The closed and evaporating columns were designed similarly with about 18 ℃ temperatures differences between the top and bottom boundary, except of the upper end closed or exposed to the air, respectively.Results showed that in the closed column, water moved towards the cold end driven by temperature gradient, while the transported water decreased with the increasing initial soil water content until the initial soil water content reached to field capacity equivalent,when almost no changes for the soil moisture profile. In the evaporating column, the net transport of soil water was simultaneously driven by evaporation and temperature gradients, and the drier soil was more influenced by temperature gradient than by evaporation. In drier soil, it took a longer time for the temperature to reach equilibrium, because of more net amount of transported water.

  18. Soil metagenomics and tropical soil productivity

    OpenAIRE

    Karen A Garrett

    2009-01-01

    This presentation summarizes research in the soil metagenomics cross cutting research activity. Soil metagenomics studies soil microbial communities as contributors to soil health.C CCRA-4 (Soil Metagenomics)

  19. Soil microbiology and soil health assessment

    Science.gov (United States)

    Soil scientists have long recognized the importance of soil biology in ecological health. In particular, soil microbes are crucial for many soil functions including decomposition, nutrient cycling, synthesis of plant growth regulators, and degradation of synthetic chemicals. Currently, soil biologis...

  20. Numerical Simulations of Settlement of Jet Grouting Columns

    Directory of Open Access Journals (Sweden)

    Juzwa Anna

    2016-03-01

    Full Text Available The paper presents the comparison of results of numerical analyses of interaction between group of jet grouting columns and subsoil. The analyses were conducted for single column and groups of three, seven and nine columns. The simulations are based on experimental research in real scale which were carried out by authors. The final goal for the research is an estimation of an influence of interaction between columns working in a group.

  1. Anchoring FRP laminates for the seismic strengthening of RC columns

    OpenAIRE

    Sadone, Raphaëlle; Quiertant, Marc; FERRIER, Emmanuel; Chataigner, Sylvain; Mercier, Julien

    2012-01-01

    This paper aims to examine the effectiveness of seismic strengthening of reinforced concrete (RC) columns by externally bonded Fibre Reinforced Polymer (FRP). Particularly, a novel strengthening system, designed for the flexural strengthening of columns is studied. This flexural strengthening is achieved by FRP plates bonded longitudinally and anchored at the column-stub junction. The proposed system is validated through an experimental campaign carried out on full-scale RC columns. Different...

  2. Flexural strength enhancement of confined reinforced concrete columns

    OpenAIRE

    Pam, HJ; Ho, JCM

    2001-01-01

    As part of a continuing research study, this paper proposes a new design aid to calculate the actual moment capacity of confined reinforced concrete columns. Up to now the moment capacity of a reinforced concrete column is calculated based on the code's guidelines for an unconfined section. As most reinforced concrete columns contain transverse or confining reinforcement, which will enhance the column moment capacity, the actual moment capacity will be much higher than the unconfined moment c...

  3. QR factorization for row or column symmetric matrix

    Institute of Scientific and Technical Information of China (English)

    ZOU; Hongxing(邹红星); WANG; Dianjun(王殿军); DAI; Qionghai(戴琼海); LI; Yanda(李衍达)

    2003-01-01

    The problem of fast computing the QR factorization of row or column symmetric matrix isconsidered. We address two new algorithms based on a correspondence of Q and R matrices between the rowor column symmetric matrix and its mother matrix. Theoretical analysis and numerical evidence show that, fora class of row or column symmetric matrices, the QR factorization using the mother matrix rather than therow or column symmetric matrix per se can save dramatically the CPU time and memory without loss of anynumerical precision.

  4. Soils - Volusia County Soils (Polygons)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Soils: 1:24000 SSURGO Map. Polygon boundaries of Soils in Volusia County, downloaded from SJRWMD and created by NRCS and SJRWMD. This data set is a digital version...

  5. Application of wastewater with high organic load for saline-sodic soil reclamation focusing on soil purification ability

    Directory of Open Access Journals (Sweden)

    M.A. Kameli

    2017-04-01

    Full Text Available Fresh water source scarcity in arid and semiarid area is limitation factor for saline-sodic soil reclamation. The reusing of agricultural drainage and industrial wastewater are preferred strategies for combating with this concern. The objective of current study was evaluation in application of industrial sugar manufacture wastewater due to high soluble organic compounds in saline-sodic and sodic soil. Also soil ability in wastewater organic compounds removal was second aim of present study. Saline-sodic and sodic soil sample was leached in soil column by diluted wastewater of amirkabir sugar manufacture in Khuzestan Province of Iran at constant water head. Sodium, electric conductivity and chemical oxygen demand of soil column leachate were measured per each pore volume. The experimental kinetics of wastewater organic compounds on two saline-sodic and sodic soil were also investigated by three pseudo second order, intra particle diffusion and elovich model. The results of current study showed that electric conductivity of saline-sodic soil was decreased to 90% during 3 initial pore volumes, from other side exchangeable sodium percent of saline-sodic and sodic soil decreased 30 and 71 percent, respectively. There were no significant different between wastewater chemical oxygen demand removal by saline-sodic and sodic soil in both batch and column studies. Wastewater chemical oxygen demand was decreased to 35% during pass through soil column. The results showed that the adsorption kinetics of wastewater organic compounds were best fitted by the pseudo-second order model with 99 percent correlation coefficient (r2=0.99%.

  6. 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.

  7. Self-organizing strategies for a column-store database

    NARCIS (Netherlands)

    Ivanova, M.G.; Kersten, M.L.; Nes, N.J.

    2008-01-01

    Column-store database systems open new vistas for improved maintenance through self-organization. Individual columns are the focal point, which simplify balancing conflicting requirements. This work presents two workload-driven self-organizing techniques in a column-store, i.e. adaptive segmentation

  8. Mechanistic model for dispersion coefficients in bubble column

    CSIR Research Space (South Africa)

    Skosana, PJ

    2015-05-01

    Full Text Available A mechanistic model describing the mass and momentum exchange in bubble columns is proposed that is based on the observations that the gas distribution in a bubble column is not uniform across the column and that as a consequence large liquid...

  9. Microbial effect on soil hydraulic properties

    Science.gov (United States)

    Furman, Alex; Rosenzweig, Ravid; Volk, Elazar; Rosenkranz, Hella; Iden, Sascha; Durner, Wolfgang

    2014-05-01

    Although largely ignored, the soil contains large amount of biofilms (attached microbes) that can affect many processes. While biochemical processes are studied, biophysical processes receive only little attention. Biofilms may occupy some of the pore space, and by that affect the soil hydraulic properties. This effect on unsaturated soils, however, was not intensively studied. In this research we directly measure the hydraulic properties, namely the soil's unsaturated hydraulic conductivity function and retention curve, for soils containing real biofilm. To do that we inoculate soil with biofilm-forming bacteria and incubate it with sufficient amounts of nutrient until biofilm is formed. The hydraulic properties of the incubated soil are then measured using several techniques, including multi-step outflow and evaporation method. The longer measurements (evaporation method) are conducted under refrigeration conditions to minimize microbial activity during the experiment. The results show a clear effect of the biofilm, where the biofilm-affected soil (sandy loam in our case) behaves like a much finer soil. This qualitatively makes sense as the biofilm generates an effective pore size distribution that is characterized by smaller pores. However, the effect is much more complex and needs to be studied carefully considering (for example) dual porosity models. We compare our preliminary results with other experiments, including flow-through column experiments and experiments with biofilm analogues. Clearly a better understanding of the way microbial activity alters the hydraulic properties may help designing more efficient bioremediation, irrigation, and other soil-related processes.

  10. Heavy Metals in a Sulfidic Minespoil: Fractions and Column Leaching

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Fractions of various heavy metals in a sulfidic minespoil were investigated. Column leaching experimentwas also conducted to simulate "acid mine drainage" (AMD) from the minespoil. The results show thatleaching of heavy metals from the minespoil was extremely significant during the initial water flushing.The amounts of heavy metals leached out dramatically reduced after leaching twice. It is worthwhile tonote that in this study, Zn, Mn, Fe, As and Ni in the first leachate exceeded the total amount of eachcorresponding water-extractable (1:5, soil:water) metal contained in the minespoil sample. This appears tosuggest that 1:5 water extraction did not allow accurate estimation of water-leachable concentrations of theabove heavy metals. This work has implications for the management of sulfidic minespoils. Acid drainageof great environmental concerns is likely to occur only during heavy rainfall events after substantial solubleand readily exchangeable acid and metals are accumulated in the minespoils. The slow-reacting fractionsother than water-soluble and readily exchangeable fractions may pose little environmental hazards. This isparticularly true for Pb, As and Ni.

  11. Soil pollution and soil protection.

    NARCIS (Netherlands)

    Haan, de F.A.M.; Visser-Reijneveld, M.I.

    1996-01-01

    This book was compiled from lecture handouts prepared for the international postgraduate course on soil quality, entitled 'Soil Pollution and Soil Protection' given jointly by the universities of Wageningen (The Netherlands), Gent and Leuven (Belgium), under the auspices of the international

  12. Comparison between a spray column and a sieve tray column operating as liquid-liquid heat exchangers

    Science.gov (United States)

    Keller, A. S.; Jacobs, H. R.; Boehm, R. F.

    The reported investigation was conducted in connection with research intended to improve the efficiency of direct contact devices for geothermal and solar applications. The investigation had the objective to evaluate the effect of adding sieve trays to the laboratory column used in studies concerned with the development of models for spray column heat transfer. Hot water is pumped from a supply vessel into the top of the heat exchanger column where, as the continuous phase, it flows down through the column. The dispersed phase is kerosene. Using an identical pump to that used for the water, the kerosene flows into a dispersion plate in the bottom of the column. The droplets rise through the column and coalesce at the top. It was found that the heat transfer performance of the perforated plate column was significantly improved over that in a spray column for similar operating conditions.

  13. Enhanced nitrobenzene removal and column longevity by coupled abiotic and biotic processes in zero-valent iron column

    DEFF Research Database (Denmark)

    Yin, Weizhao; Wu, Jinhua; Huang, Weilin;

    2015-01-01

    /or co-precipitation and the reduction of NB to aniline (AN) via abiotic reaction in the abiotic column and via both abiotic and biotic reactions in the biotic column. Due to the interactive effect of ZVI and microorganisms, more effective iron consumption and more reactive minerals such as green rust......In this study, abiotic zero-valent iron (ZVI) column and biotic ZVI column were employed to investigate abiotic and biotic effects between iron and microorganisms on NB removal and column longevity. Physical removal and kinetics analysis revealed that NB was largely removed through adsorption and...... and iron sulfide were found in the biotic column. This led to approximately 50% higher total NB removal and 6 times higher AN production in the biotic column as compared to the abiotic column during the entire operation. According to the NB breakthrough curves, longer stability and longer life...

  14. Soil infiltrometer

    Energy Technology Data Exchange (ETDEWEB)

    Mehler, M.R.

    1990-09-18

    This patent describes an infiltrometer useful for field testing soil permeability. It comprises: a large reservoir having an open bottom resting on the soil; a small reservoir having an open bottom resting on the soil, the small reservoir being positioned within the large reservoir; the small reservoir comprising a relatively large receptacle adjacent the soil and a relatively small receptacle connected thereto and extending upwardly therefrom; the volume of the large reservoir greatly exceeding the volume of the small reservoir; the ratio of the upper surface area of liquid in the large reservoir to the surface area of the soil covered thereby greatly exceeding the ratio of the upper surface area of liquid in the relatively small receptacle of the small reservoir to the surface area of the soil covered thereby; and means for determining the amount of liquid from the small reservoir permeating into the soil.

  15. Behaviour of Soil Subjected to Dynamic Loads

    DEFF Research Database (Denmark)

    Bødker, L.

    1998-01-01

    Many geotechnical problems involve design of dynamically loaded foundations. The design criterion fr dynamically loaded foundations is often described in terms of limiting values for the displacements. The displacements in the soil are normally very small when dealing with dynamically loaded...... foundations, and hence it is necessary to know the deformation properties for the soil at very low strain level. The main topic of the project is to increase the knowledge of the behaviour of Danish soils at small strain levels and to extend the laboratory facilities to deal with testing at small strains....... The soil behaviour at very small strain levels is non-linear, and the most common testing technique for this situation is the resonant column technique. One of the aims of this project is to install, check, get familiar with and perform tests on different kinds of Danish soils in a new Drnevich...

  16. Phosphorus leaching in a soil textural gradient

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Kjærgaard, Charlotte; Rubæk, Gitte Holton;

    2009-01-01

    Texture is a major factor influencing mobilization and transport of P in soil owing partly to differences in adsorptive properties, and partly to differences in pore-size distribution and pore organization. Slurry application strategies may be important mitigation measures for reducing agricultural...... P leaching. We propose diverse interactions between dominant flow pathways and cattle slurry: - Injection of slurry reduces P leaching compared to surface application in soils with preferential flow behaviour - Injection of slurry has less impact on P leaching compared to surface application...... in soils with matrix dominated flow behaviour We tested these hypotheses on three textural soil classes (Olsen-P 1.6 mg P 100 g-1) on intact soil columns (20*20 cm) and compared them to in situ P leaching before slurry application. In a loamy sand P leaching with both slurry application techniques slightly...

  17. Temporal and Spatial Distribution of the Microbial Community of Winogradsky Columns.

    Directory of Open Access Journals (Sweden)

    David J Esteban

    Full Text Available Winogradsky columns are model microbial ecosystems prepared by adding pond sediment to a clear cylinder with additional supplements and incubated with light. Environmental gradients develop within the column creating diverse niches that allow enrichment of specific bacteria. The enrichment culture can be used to study soil and sediment microbial community structure and function. In this study we used a 16S rRNA gene survey to characterize the microbial community dynamics during Winogradsky column development to determine the rate and extent of change from the source sediment community. Over a period of 60 days, the microbial community changed from the founding pond sediment population: Cyanobacteria, Chloroflexi, Nitrospirae, and Planctomycetes increased in relative abundance over time, while most Proteobacteria decreased in relative abundance. A unique, light-dependent surface biofilm community formed by 60 days that was less diverse and dominated by a few highly abundant bacteria. 67-72% of the surface community was comprised of highly enriched taxa that were rare in the source pond sediment, including the Cyanobacteria Anabaena, a member of the Gemmatimonadetes phylum, and a member of the Chloroflexi class Anaerolinea. This indicates that rare taxa can become abundant under appropriate environmental conditions and supports the hypothesis that rare taxa serve as a microbial seed bank. We also present preliminary findings that suggest that bacteriophages may be active in the Winogradsky community. The dynamics of certain taxa, most notably the Cyanobacteria, showed a bloom-and-decline pattern, consistent with bacteriophage predation as predicted in the kill-the-winner hypothesis. Time-lapse photography also supported the possibility of bacteriophage activity, revealing a pattern of colony clearance similar to formation of viral plaques. The Winogradsky column, a technique developed early in the history of microbial ecology to enrich soil

  18. Temporal and Spatial Distribution of the Microbial Community of Winogradsky Columns.

    Science.gov (United States)

    Esteban, David J; Hysa, Bledi; Bartow-McKenney, Casey

    2015-01-01

    Winogradsky columns are model microbial ecosystems prepared by adding pond sediment to a clear cylinder with additional supplements and incubated with light. Environmental gradients develop within the column creating diverse niches that allow enrichment of specific bacteria. The enrichment culture can be used to study soil and sediment microbial community structure and function. In this study we used a 16S rRNA gene survey to characterize the microbial community dynamics during Winogradsky column development to determine the rate and extent of change from the source sediment community. Over a period of 60 days, the microbial community changed from the founding pond sediment population: Cyanobacteria, Chloroflexi, Nitrospirae, and Planctomycetes increased in relative abundance over time, while most Proteobacteria decreased in relative abundance. A unique, light-dependent surface biofilm community formed by 60 days that was less diverse and dominated by a few highly abundant bacteria. 67-72% of the surface community was comprised of highly enriched taxa that were rare in the source pond sediment, including the Cyanobacteria Anabaena, a member of the Gemmatimonadetes phylum, and a member of the Chloroflexi class Anaerolinea. This indicates that rare taxa can become abundant under appropriate environmental conditions and supports the hypothesis that rare taxa serve as a microbial seed bank. We also present preliminary findings that suggest that bacteriophages may be active in the Winogradsky community. The dynamics of certain taxa, most notably the Cyanobacteria, showed a bloom-and-decline pattern, consistent with bacteriophage predation as predicted in the kill-the-winner hypothesis. Time-lapse photography also supported the possibility of bacteriophage activity, revealing a pattern of colony clearance similar to formation of viral plaques. The Winogradsky column, a technique developed early in the history of microbial ecology to enrich soil microbes, may therefore be

  19. Influence of Formulation on Mobility of Clomazone in Soil.

    Science.gov (United States)

    Włodarczyk, Małgorzata; Siwek, Hanna

    2016-10-01

    The mobility of clomazone [2-(2-chlorobenzylo)-4,4-dimetylo-1,2-oxazolidin-3-one] in a loamy sand soil and a sand soil was studied in a soil column under laboratory conditions. Commercial clomazone formulation (Command 480 EC) and clomazone immobilized in an alginate matrix were used for a leaching experiment. For both formulations, the same dose of 2.0 mg of the active substance was applied. After an application of a herbicide, the columns were irrigated with: 100, 40 and 3.7 mm of water. After 1 h, when an addition of water was completed, the soils were sampled in the 5 cm segments and were used for the analysis of the residues. The use of an alginate formulation reduced the vertical mobility of clomazone into a soil layer in comparison with the formulation EC.

  20. Detecting soil water use by Mediterranean vegetation on rocky soils using electrical resistivity tomography.

    NARCIS (Netherlands)

    Nijland, W.; van der Meijde, M.; Addink, E. A.; de Jong, S. M.; van der Meer, F. D.

    2009-01-01

    Water availability is an important constraint on tree and shrub development in Mediterranean ecosystems. During prolonged periods of summer drought, water stored in the soil column is the only available water source. Some Mediterranean tree species are known to have extensive root system penetrating

  1. Geophysical Monitoring of Microbial Activity within a Wetland Soil

    Science.gov (United States)

    O'Brien, M.; Zhang, C.; Ntarlagiannis, D.; Slater, L.; Yee, N.

    2007-05-01

    We performed Induced Polarization (IP) and Self Potential (SP) measurements to record the geoelectrical signatures of microbial activity within a wetland soil. The experiment was conducted in laboratory, utilizing an open flow column set up. Soil samples from Kearny Marsh (KM), a shallow water wetland, were collected and stored at 4o Celsius prior to the start of the experiment. Two columns were dry packed with a mix of KM soil and sterile Ottawa sand (50% by weight). One column was sterilized and used as a control while the other column retained the biologically active soil sample. Both columns were saturated with a minimal salts medium capable of supporting microbial life; after saturation, a steady flow rate of one pore volume per day was maintained throughout the experiment. Ambient temperature and pressure changes (at the inflow and outflow of each column) were continuously monitored throughout the experiment. Common geochemical parameters, such as Eh, pH, and fluid conductivity were measured at the inflow and outflow of each column at regular intervals. IP and SP responses were continuously recorded on both columns utilizing a series of electrodes along the column length; additionally for the SP measurements we used a reference electrode at the inflow tube. Strong SP anomalies were observed for all the locations along the active column. Black visible mineral precipitant also formed in the active column. The observed precipitation coincided with the times that SP anomalies developed at each electrode position. These responses are associated with microbial induced sulfide mineralization. We interpret the SP signal as the result of redox processes associated with this mineralization driven by gradients in ionic concentration and mobility within the column, similar to a galvanic cell mechanism. IP measurements show no correlation with these visual and SP responses. Destructive analysis of the samples followed the termination of the experiment. Scanning electron

  2. ANALYSIS OF PERFLUORINATED CARBOXYLIC ACIDS IN SOILS II: OPTIMIZATION OF CHROMATOGRAPHY AND EXTRACTION

    Science.gov (United States)

    With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorinated octanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary p...

  3. ANALYSIS OF PERFLUORINATED CARBOXYLIC ACIDS IN SOILS II: OPTIMIZATION OF CHROMATOGRAPHY AND EXTRACTION

    Science.gov (United States)

    With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorinated octanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary p...

  4. Comment on "Column-scale unsaturated hydraulic conductivity estimates in coarse-textured homogeneous and layered soils derived under steady-state evaporation from a water table" by M. Sadeghi, M. Tuller, M.R. Gohardoust and S.B. Jones

    Science.gov (United States)

    Lehmann, Peter; Assouline, Shmuel; Or, Dani

    2015-10-01

    The authors presented a new solution for steady-state evaporation during stage II from coarse-textured porous media (under isothermal conditions) that enables to (i) compute the maximum distance Dmax between the water table and the vaporization plane (where water phase change from liquid to vapor occurs) for a certain evaporation rate e and (ii) estimate the unsaturated hydraulic conductivity K(h) as a function of capillary head h by measuring e(Dmax). The mathematical procedure presented is correct and interesting, however, the study makes various unsubstantiated claims regarding potential generalization of the results that deserve some scrutiny considering the wealth of experimental and other physically-based theoretical studies of this important phenomenon. The general outcome is that we consider the conclusion as presented in the abstract ;The presented approach offers an alternative method for determination of unsaturated hydraulic conductivity of homogeneous coarse-textured soils and a new solution for prediction of the effective unsaturated hydraulic conductivity of layered coarse-textured soils; unfounded. In the comment below we address (i) the confusion between different definitions of hydraulic continuity of the liquid phase, (ii) the limited application of the method to a small range of evaporative fluxes, (iii) the plausibility of interpretations assuming hydraulic continuity across 10's of meters, (iv) the correctness of the estimations of maximum hydraulic continuity length Dmax from water table depth D for the coarse textured media considered in the study, and (v) a questionable application of the method for layered profiles. We first comment on some of the key derivations and their relations to soil properties and boundary conditions, and then discuss the physical validity of some of the generalization claims.

  5. From Single Droplet to Column Design

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The technique state to design counter-current extraction columns is based on the performance of pilot plant experiments. The modelling is then either with the equilibrium or dispersion model, whereas in the latter the dispersion coefficient accounts for all hydrodynamic non-idealities. A new approach uses single droplet experiments to obtain the basic laws and functions governing droplet breakage, coalescence,relative velocity, and axial dispersion when using droplet populance balance models (DPBM). The hydrodynamics simulation results show that the mean Sauter diameter, hold-up, and concentration profiles could be well predicted, which promotes the use of DPBM models for further applications in industrial scale.

  6. Column: The Physics of Digital Information

    Directory of Open Access Journals (Sweden)

    Fred Cohen

    2011-09-01

    Full Text Available One of the interesting questions underlying creating a science of digital forensics is what form that science might take. At the end of the IEEE Oakland Conference in 2011, I presented some of the underlying questions and identified my approach and why I favored it.2 My basic position is that science is about causality and a scientific theory should require that cause(C produces effect (E via mechanism M (written C→ME. The scientific method then identifies the criteria for rejecting (refuting or accepting (for a time a scientific theory.(see PDF for full column

  7. Lattice approaches to packed column simulations

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This work presents a review of the findings into the ability of a digitally based particle packing algorithm, called DigiPac, to predict bed structure in a variety of packed columns, for a range of generic pellet shapes frequently used in the chemical and process engineering industries.Resulting macroscopic properties are compared with experimental data derived from both invasive and non-destructive measurement techniques.Additionally, fluid velocity distributions, through samples of the resulting bed structures, are analysed using lattice Boltzmann method (LBM) simulations and are compared against experimental data from the literature.

  8. Hydrodynamic Study Of Column Bioleaching Processes

    Directory of Open Access Journals (Sweden)

    Sadowski Zygmunt

    2015-06-01

    Full Text Available The modelling of flow leaching solution through the porous media has been considered. The heap bioleaching process can be tested using the column experimental equipment. This equipment was employed to the hydrodynamic studies of copper ore bioleaching. The copper ore (black shale ore with the support, inertial materials (glass small balls and polyethylene beads was used to the bioleaching tests. The packed beds were various composition, the ore/support ratio was changed. The correlation between the bed porosity and bioleaching kinetics, and copper recovery was investigated.

  9. Preinjector for Linac 1, accelerating column

    CERN Multimedia

    1974-01-01

    For a description of the Linac 1 preinjector, please see first 7403070X. High up on the wall of the Faraday cage (7403073X) is this drum-shaped container of the ion source (7403083X). It is mounted at the HV end of the accelerating column through which the ions (usually protons; many other types of ions in the course of its long history) proceed through the Faraday cage wall to the low-energy end (at ground potential) of Linac 1. The 520 kV accelerating voltage was supplied by a SAMES generator (7403074X).

  10. Effects of Application of Biogas Slurry on the Form and Mobility of Soil Phosphorus in Vegetable Greenhouse Field

    Directory of Open Access Journals (Sweden)

    WANG Min-feng

    2017-06-01

    Full Text Available A packed soil column experiment was conducted to investigate the effects of biogas slurry on phosphorus(P form and mobility in a vegetable greenhouse soil with different P fertility levels. The results showed that application of biogas slurry all significantly reduced leachate volume and total phosphorus leaching in the experimental soil with different fertility levels. Compared with control treatments, the application of biogas slurry decreased total phosphorus content in leachate by 722.3 μg·column-1 through reducing leachate volume. Total inorganic phosphorus(TIP decreased by 507.2 μg·column-1 and 1 319 μg·column-1 in the moderate-P-fertility and high-P-fertility soil, respectively. Dissolved inorganic phosphorus(DIP was decreased by 158.1 μg·column-1 and 474.3 μg·column-1 in the low-P-fertility and moderate-P-fertility soil, respectively. In low-P-fertility soil, biogas slurry application significantly increased soil total P, Olsen-P and organic P in 0~7 cm soil depth by a proportion of 34.8%, 37.7% and 148%, respectively. It also reduced soil pH by 0.39 units. In 7~14 cm soil depth, biogas slurry application significantly increased soil total P, Olsen-P and organic P by a proportion of 18.5%, 29.3% and 32.9%, respectively. SoipH was also decreased by 0.28 units. In moderate-P-fertility soil, application of biogas slurry had no significantly influence on soil total P, but increased soil Olsen-P by 20.1% in 0~7 cm soil depth compared with control treatment. In 7~14 cm soil depth, application of biogas slurry reduced soil pH by 0.33 units. In high-P-fertility soil, application of biogas slurry had no significantly influence on soil total P, Olsen-P and organic P in 0~7 cm soil depth compared with control treatment. In 7~14 cm soil depth, application of biogas slurry reduced soil pH by 0.34 units. In conclusion, application of biogas slurry significantly increased different forms of phosphorus contents in low-P-fertility soil, however

  11. Influence of Redox Potential on Arsenic Release from Soil in the Presence of Iron Oxyhydroxide

    OpenAIRE

    Nguyen, Kim Phuong; Itoi, Ryuichi; Yamashiro, Rie

    2008-01-01

    This paper presents the effects redox potential on the mobility of arsenic (As) from soil in the presence of iron oxyhydroxide with soil column experiment. The mineralogical characteristics of the soil were identified by acid digestion, X-ray diffraction and sequential extraction methods. Approximately 60% of the total arsenic was associated with iron oxyhydroxides and iron oxides. Redox potential played a significant role on the onset of arsenic and iron release from the soil. The arsenic an...

  12. A new low carbon cementitious binder for stabilising weak ground conditions through deep soil mixing.

    OpenAIRE

    Sargent, P.; Hughes, P. N.; Rouainia, M.

    2016-01-01

    Soft alluvial soils present unfavourable conditions for engineering developments due to their poor bearing capacities and high potential for experiencing shrinkage and swelling. This paper focusses on deep dry soil mixing (DDSM), which introduces cementitious binders to soft soils via a rotating auger drill, thereby producing soil-cement columns. Ordinary Portland cement (CEM-I) is globally used across the construction industry and is the most commonly used binder for DDSM applications due to...

  13. Hydrodynamics and Mass Transfer Performance in Supercritical Fluid Extraction Columns

    Institute of Scientific and Technical Information of China (English)

    石冰洁; 张泽廷; 等

    2002-01-01

    New models for describing hydrodynamics and mass transfer performance in supercritical fluid extraction columns were proposed.Those models were proved by experimental data,which were obtained in supercritical fluid extraction packed column,spray column and sieve tray column respectively.The inner diameter of those columns areΦ25mm,These experimental systems include supercritical carbon dioxideisopropanol-water and supercritical carbon dioxide-ethanol-water,in which supercritical carbon dioxide was dispersed phase,and another was continuous phase.The extraction processes were operated with continuous countercurrent flow.The predicted values are agreed well with experimental data.

  14. Antimony (Sb) contaminated shooting range soil: Sb mobility and immobilization by soil amendments.

    Science.gov (United States)

    Okkenhaug, Gudny; Amstätter, Katja; Lassen Bue, Helga; Cornelissen, Gerard; Breedveld, Gijs D; Henriksen, Thomas; Mulder, Jan

    2013-06-18

    Antimony (Sb) in lead bullets poses a major environmental risk in shooting range soils. Here we studied the effect of iron (Fe)-based amendments on the mobility of Sb in contaminated soil from shooting ranges in Norway. Untreated soil showed high Sb concentrations in water extracts from batch tests (0.22-1.59 mg L(-1)) and soil leachate from column tests (0.3-0.7 mg L(-1)), occurring exclusively as Sb(V). Sorption of Sb to different iron-based sorbents was well described by the Freundlich equation (Fe2(SO4)3, log KF = 6.35, n = 1.51; CFH-12 (Fe oxyhydroxide), log KF = 4.16-4.32, n = 0.75-0.76); Fe(0) grit, log KF = 3.26, n = 0.47). These sorbents mixed with soil (0.5 and 2% w/w), showed significant sorption of Sb in batch tests (46-92%). However, for Fe2(SO4)3 and CFH-12 liming was also necessary to prevent mobilization of lead, copper, and zinc. Column tests showed significant retention of Sb (89-98%) in soil amended with CFH-12 (2%) mixed with limestone (1%) compared to unamended soil. The sorption capacity of soils amended with Fe(0) (2%) increased steadily up to 72% over the duration period of the column test (64 days), most likely due to the gradual oxidation of Fe(0) to Fe oxyhydroxides. Based on the experimental results, CFH-12 and oxidized Fe(0) are effective amendments for the stabilization of Sb in shooting range soils.

  15. ANALYSIS OF FERRIC AND FERROUS IONS IN SOIL EXTRACTS BY ION CHROMATOGRAPHY

    Science.gov (United States)

    A method using ion chromatography (IC) for the analysis of ferrous (Fe 2+) and ferric (Fe 3+) ions in soil extracts has been developed. This method uses an ion exchange column with detection at 520 nm after post-column derivatization. Selectivity is achieved by using an anionic...

  16. ANALYSIS OF FERRIC AND FERROUS IONS IN SOIL EXTRACTS BY ION CHROMATOGRAPHY

    Science.gov (United States)

    A method using ion chromatography (IC) for the analysis of ferrous (Fe 2+) and ferric (Fe 3+) ions in soil extracts has been developed. This method uses an ion exchange column with detection at 520 nm after post-column derivatization. Selectivity is achieved by using an anionic...

  17. Multi-Scale Process of Soil Freezing, Thawing, and Thaw-Settlement

    Science.gov (United States)

    2013-02-18

    utilities, cracked pavements , jacked up bridge foundations, tilted structures, are all examples of damage suffered from frost action. Long-term...a thermal process was simulated. The soil column is 0.07 m in height. The vertical walls of the column are adiabatic and rigid . The initial

  18. Identification of TCE and PCE sorption and biodegradation parameters in a sandy aquifer for fate and transport modelling: batch and column studies

    OpenAIRE

    Kret, E.; Kiecak, A.; Malina, G.; Nijenhuis, I.; Postawa, A.

    2015-01-01

    The main aim of this study was to determine the sorption and biodegradation parameters of trichloroethene (TCE) and tetrachloroethene (PCE) as input data required for their fate and transport modelling in a Quaternary sandy aquifer. Sorption was determined based on batch and column experiments, while biodegradation was investigated using the compound-specific isotope analysis (CSIA). The aquifer materials medium (soil 1) to fine (soil 2) sands and groundwater samples came from the representat...

  19. Soils, Pores, and NMR

    Science.gov (United States)

    Pohlmeier, Andreas; Haber-Pohlmeier, Sabina; Haber, Agnes; Sucre, Oscar; Stingaciu, Laura; Stapf, Siegfried; Blümich, Bernhard

    2010-05-01

    Within Cluster A, Partial Project A1, the pore space exploration by means of Nuclear Magnetic Resonance (NMR) plays a central role. NMR is especially convenient since it probes directly the state and dynamics of the substance of interest: water. First, NMR is applied as relaxometry, where the degree of saturation but also the pore geometry controls the NMR signature of natural porous systems. Examples are presented where soil samples from the Selhausen, Merzenhausen (silt loams), and Kaldenkirchen (sandy loam) test sites are investigated by means of Fast Field Cycling Relaxometry at different degrees of saturation. From the change of the relaxation time distributions with decreasing water content and by comparison with conventional water retention curves we conclude that the fraction of immobile water is characterized by T1 samples (Haber-Pohlmeier et al. 2010). Third, relaxometric information forms the basis of understanding magnetic resonance imaging (MRI) results. The general difficulty of imaging in soils are the inherent fast T2 relaxation times due to i) the small pore sizes, ii) presence of paramagnetic ions in the solid matrix, and iii) diffusion in internal gradients. The last point is important, since echo times can not set shorter than about 1ms for imaging purposes. The way out is either the usage of low fields for imaging in soils or special ultra-short pulse sequences, which do not create echoes. In this presentation we will give examples on conventional imaging of macropore fluxes in soil cores (Haber-Pohlmeier et al. 2010), and the combination with relaxometric imaging, as well as the advantages and drawbacks of low-field and ultra-fast pulse imaging. Also first results on the imaging of soil columns measured by SIP in Project A3 are given. Haber-Pohlmeier, S., S. Stapf, et al. (2010). "Waterflow Monitored by Tracer Transport in Natural Porous Media Using MRI." Vadose Zone J.: submitted. Haber-Pohlmeier, S., S. Stapf, et al. (2010). "Relaxation in a

  20. Heavy metal displacement in chelate-irrigated soil during phytoremediation

    Science.gov (United States)

    Madrid, F.; Liphadzi, M. S.; Kirkham, M. B.

    2003-03-01

    Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavy metals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavy metals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavy metals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavy metals for maximum uptake during chelate-assisted phytoremediation.

  1. Column leaching from biomass combustion ashes

    DEFF Research Database (Denmark)

    Maresca, Alberto; Astrup, Thomas Fruergaard

    2015-01-01

    The utilization of biomass combustion ashes for forest soil liming and fertilizing has been addressed in literature. Though, a deep understanding of the ash chemical composition and leaching behavior is necessary to predict potential benefits and environmental risks related to this practice...

  2. Mimicking pestcide percolation dynamics in ditches bed by successive column infltration experiment

    Science.gov (United States)

    Dages, Cecile; Samouelian, Anatja; Storck, Veronika; Negro, Sandrine; Huttel, Olivier; Voltz, Marc

    2014-05-01

    Soil layers underlying ditch beds acquire specific characteristics due to ii) hydrological and erosion/deposition processes occurring within the ditch and ii) management practices (burning, dredging, mowing, …). For example, organic matter contents of the ditch beds can be larger than those in neighboring fields, since ditches act as buffer zones. Besides, in Mediterranean catchments, farmed ditches are known to be zones of groundwater recharge and thereby may contribute to groundwater pollution. The role of farmed ditches in groundwater contamination needs therefore to be clarified. The purpose of this study was to determine the dynamic of pesticide percolation in infiltrating farmed ditches bed during a sequence of flood events. A complementary aim was to determine to which extent pesticide percolation from the ditches is correlated to surface flow water contamination. A succession of 9 flood simulations were performed on an undisturbed soil column sampled in the a ditch of the Roujan catchment (Hérault, France), which belongs to the long term Mediterranean hydrological observatory OMERE (Voltz and Albergel, 2002). The soil column was 15 cm long with a 15 cm inner-diameter. For the first 5 flood simulations, injected water was doped with 14C-diuron, an herbicide used in vineyards; uncontaminated water was injected for the last 4 simulations. Free drainage was imposed at the bottom of the column. Diuron concentration was kept constant during a simulated infiltration experiment, but it was progressively decreased from 1000 to 0 µg/L along the succession of the 9 events to mimic the observed seasonal variation of mean diuron concentration in surface flow at the study site (Louchart et al., 2001). Additionally, the first flood simulation was performed with tritium water to assess references on conservative transport within the soil column. For each simulation, the inflow and outflow hydrogram and chemogram were monitored. Extractable (water and solvent) and non

  3. The maximum force in a column under constant speed compression

    CERN Document Server

    Kuzkin, Vitaly A

    2015-01-01

    Dynamic buckling of an elastic column under compression at constant speed is investigated assuming the first-mode buckling. Two cases are considered: (i) an imperfect column (Hoff's statement), and (ii) a perfect column having an initial lateral deflection. The range of parameters, where the maximum load supported by a column exceeds Euler static force is determined. In this range, the maximum load is represented as a function of the compression rate, slenderness ratio, and imperfection/initial deflection. Considering the results we answer the following question: "How slowly the column should be compressed in order to measure static load-bearing capacity?" This question is important for the proper setup of laboratory experiments and computer simulations of buckling. Additionally, it is shown that the behavior of a perfect column having an initial deflection differ significantlys form the behavior of an imperfect column. In particular, the dependence of the maximum force on the compression rate is non-monotoni...

  4. Frontal crash simulation of vehicles against lighting columns using FEM

    Directory of Open Access Journals (Sweden)

    Yehia A. Abdel-Nasser

    2013-09-01

    Full Text Available There are many severe and fatal crashes that result from vehicles colliding with street columns such as lighting columns. These cause extremely high impact forces and deformation on the frontal area of the car. The objective of the study is to demonstrate the frontal crash simulation of vehicle against lighting columns to examine injury risk and potential of safety. In particular, various FE models are used to perform contact–impact nonlinear dynamic analysis of lighting columns with vehicle. In this paper Abaqus explicit code is used to numerically simulate the crash of the vehicle with present columns and other lighting columns fabricated from a new suggested material. The acceleration, contact force and deformed energy at the frontal region of the vehicle are traced. It is found that the lighting columns with new suggested material have impact properties to decelerate the vehicle and absorb higher energy during impact.

  5. Effect of Polyphosphate-accumulating Organisms on Phosphorus Mobility in Variably Saturated Sand Columns

    Science.gov (United States)

    Stockton, M.; Rojas, C.; Regan, J. M.; Saia, S. M.; Buda, A. R.; Carrick, H. J.; Walter, M. T.

    2016-12-01

    Excessive application of phosphorus-containing fertilizer along with incomplete knowledge about the factors affecting phosphorus transport and mobility has allowed for a growing number of cases of eutrophication in water bodies. Previous research on enhanced biological phosphorus removal (EBPR) systems used in wastewater treatment plants (WWTPs) has identified polyphosphate-accumulating organisms (PAOs) that are known to accumulate and release phosphorus depending on aerobic/anaerobic conditions. Under anaerobic conditions, intracellular polyphosphate (poly-P) bodies are hydrolyzed releasing phosphate, while under aerobic conditions phosphate is taken up and poly-P inclusions are reformed. The presence of PAOs outside of WWTPs has been shown, but their potential impact on phosphorus mobility in other contexts is not as well known. To study that potential impact, sand columns were subjected to alternating cycles of saturation and unsaturation to mimic variably saturated soils and the resultant anaerobic and aerobic conditions that select for PAOs in a WWTP. Pore water samples collected from sterile control columns and columns inoculated with PAOs from a WWTP were compared during each cycle to monitor changes in dissolved inorganic phosphate and total phosphorus concentrations. In addition, continuous redox data were collected to confirm reducing conditions developed during periods of saturation. Sand particles will be subjected to FISH and DAPI staining to visualize PAOs using probes developed for PAOs in EBPR processes and to determine if changes in intracellular poly-P are detectable between the two cycles in the inoculated columns. Studying the effects of PAOs on phosphorus mobility in these controlled column experiments can contribute to understanding phosphorus retention and release by naturally occurring PAOs in terrestrial system, which ultimately can improve the development of management practices that mitigate phosphorus pollution of water bodies.

  6. Simple, specific analysis of organophosphorus and carbamate pesticides in sediments using column extraction and gas chromatography

    Science.gov (United States)

    Belisle, A.A.; Swineford, D.M.

    1988-01-01

    A simple, specific procedure was developed for the analysis of organophosphorus and carbamate pesticides in sediment. The wet soil was mixed with anhydrous sodium sulfate to bind water and the residues were column extracted in acetone:methylene chloride (1:l,v/v). Coextracted water was removed by additional sodium sulfate packed below the sample mixture. The eluate was concentrated and analyzed directly by capillary gas chromatography using phosphorus and nitrogen specific detectors. Recoveries averaged 93 % for sediments extracted shortly after spiking, but decreased significantly as the samples aged.

  7. Consolidation behavior of cement—and lime/cement—mixed column foundations

    Institute of Scientific and Technical Information of China (English)

    蔡袁强; 徐长节

    2002-01-01

    The consolidation behavior of mixed in place cement-and lime /cement-mixed column was studies.COnsolidation of the composite foundation was modeled as a three-dimensional axi-symmetric problem.The authors used the finite difference method to obtain the pore pressure variation with time at and location below the surface.A computer program developed by the authors was used to draw some interesting conclusions about the consolidation behaviors of cement-mixed pile foundation.Finally,a combined model including the permeability coefficients of cement-mixed piles and soil,was studied and its feasibility was evaluated.

  8. Monolithic columns in plant proteomics and metabolomics.

    Science.gov (United States)

    Rigobello-Masini, Marilda; Penteado, José Carlos Pires; Masini, Jorge Cesar

    2013-03-01

    Since "omics" techniques emerged, plant studies, from biochemistry to ecology, have become more comprehensive. Plant proteomics and metabolomics enable the construction of databases that, with the help of genomics and informatics, show the data obtained as a system. Thus, all the constituents of the system can be seen with their interactions in both space and time. For instance, perturbations in a plant ecosystem as a consequence of application of herbicides or exposure to pollutants can be predicted by using information gathered from these databases. Analytical chemistry has been involved in this scientific evolution. Proteomics and metabolomics are emerging fields that require separation, identification, and quantification of proteins, peptides, and small molecules of metabolites in complex biological samples. The success of this work relies on efficient chromatographic and electrophoretic techniques, and on mass spectrometric detection. This paper reviews recent developments in the use of monolithic columns, focusing on their applications in "top-down" and "bottom-up" approaches, including their use as supports for immobilization of proteolytic enzymes and their use in two-dimensional and multidimensional chromatography. Whereas polymeric columns have been predominantly used for separation of proteins and polypeptides, silica-based monoliths have been more extensively used for separation of small molecules of metabolites. Representative applications in proteomics and in analysis of plant metabolites are given and summarized in tables.

  9. Faster Energy Efficient Column Compression Multiplication

    CERN Document Server

    Ramkumar, B

    2011-01-01

    In this work we demonstrate that faster, energy efficient, column compression multiplication, can be achieved by using a combination of two design techniques: partitioning of the partial products into two parts for independent parallel column compression and acceleration of the final addition using a hybrid adder proposed in this work. In order to demonstrate the efficacy of the techniques we have chosen the Dadda multiplier as an example. Based on the proposed techniques 8, 16, 32 and 64-bit Dadda multipliers are developed and compared with the regular Dadda multiplier. The performance of the proposed multiplier is analyzed by evaluating the delay, area and power, with 180 nm process technologies on interconnect and layout using industry standard design and layout tools. The result analysis shows that the 64-bit regular Dadda multiplier is as much as 41.1% slower than the proposed multiplier and requires only 1.4% and 3.7% less area and power respectively. Also the power-delay product of the proposed design ...

  10. Observations of iodine monoxide columns from satellite

    Directory of Open Access Journals (Sweden)

    A. Schönhardt

    2008-02-01

    Full Text Available Iodine species in the troposphere are linked to ozone depletion and new particle formation. In this study, a full year of iodine monoxide (IO columns retrieved from measurements of the SCIAMACHY satellite instrument is presented, coupled with a discussion of their uncertainties and the detection limits. The largest amounts of IO are found near springtime in the Antarctic. A seasonal variation of iodine monoxide in Antarctica is revealed with high values in springtime, slightly less IO in the summer period and again larger amounts in autumn. In winter, no elevated IO levels are found in the areas accessible to satellite measurements. This seasonal cycle is in good agreement with recent ground-based measurements in Antarctica. In the Arctic region, no elevated IO levels were found in the period analysed. This implies that different conditions with respect to iodine release exist in the two Polar Regions. To investigate possible release mechanisms, comparisons of IO columns with those of tropospheric BrO, and ice coverage are described and discussed. Some parallels and interesting differences between IO and BrO temporal and spatial distributions are identified. Overall, the large spatial coverage of satellite retrieved IO data and the availability of a long-term dataset provide new insight about the abundances and distributions of iodine compounds in the troposphere.

  11. The effect of irrigated rice cropping on the alkalinity of two alkaline rice soils in the Sahel

    NARCIS (Netherlands)

    Asten, van P.J.A.; Zelfde, van 't J.A.; Zee, van der S.E.A.T.M.; Hammecker, C.

    2004-01-01

    Irrigated rice cropping is practiced to reclaim alkaline-sodic soils in many parts of the world. This practice is in apparent contrast with earlier studies in the Sahel, which suggests that irrigated rice cropping may lead to the formation of alkaline-sodic soils. Soil column experiments were done w

  12. Soil aquifer treatment using advanced primary effluent

    KAUST Repository

    Sharma, Saroj K.

    2011-08-01

    Soil aquifer treatment (SAT) using primary effluent (PE) is an attractive option for wastewater treatment and reuse in many developing countries with no or minimal wastewater treatment. One of the main limitations of SAT of PE is rapid clogging of the infiltration basin due to high suspended solid concentrations. Some pre-treatment of PE before infiltration is likely to reduce this limitation, improve performance of SAT and help to implement this technology effectively. The effects of three pre-treatment options namely sedimentation (SED), coagulation (COAG) and horizontal roughing filtration (HRF) on SAT were analyzed by conducting laboratory-scale batch and soil column experiments. The sedimentation and coagulation pre-treatments led to less head loss development and reduction of clogging effect. The head loss development in soil column using PE + COAG and PE + SED was reduced by 85 and 72%, respectively, compared to PE alone without any pretreatment. The overall dissolved organic carbon (DOC) removal of pre-treatments and soil column collectively were 34, 44, 51 and 43.5% for PE without any pre-treatment, PE + SED, PE+ COAG and PE + HRF, respectively. Coagulation pre-treatment of PE was found to be the most effective option in terms of suspended solids, DOC and nitrogen removal. Sedimentation pre-treatment of PE could be attractive where land is relatively less expensive for the construction of sedimentation basins. © IWA Publishing 2011.

  13. Study of clean up procedures using Charcoal-Alumina-Celite column, immunoaffinity column and strata x column to determine deoxynivalenol by high performance liquid chromatography in wheat

    Directory of Open Access Journals (Sweden)

    Jacqueline Cea

    2011-04-01

    Full Text Available Fusarium graminearum is the most common toxic fungal species affecting grains in Uruguay. Since 1977, due to favorable climate conditions, there have been harvests with prominent Fusarium Head Blight in wheat. This were in 1984, 1990, 1993, 1996 and 2001.Natural Toxin Department of Technological Laboratory of Uruguay as National Reference Laboratory, is continuously improving the analytical methods in order to have a good response to the industry requirements and to the monitoring programs for import and exports commodities. The objective of this work was to compare different clean up methods in order to select the best one for routine determination of deoxynivalenol (DON in wheat (grain and flour.  Charcoal-alumina-celite (7+5+3,  immunoaffinity columns DONPREP R-Biopharm Rhone and Strata X 33 m polymeric sorbent  Phenomenex columns were used to perform the study. Considering as reference analytical method the internal protocol  PEC.TOX.063 accredited by United Kingdom Accreditation Service (UKAS  following the ISO 17025 requirements, and  based on AOAC method 986.17( chapter 49, 2002 for extraction and clean-up  and on J.AOAC 70(3, 1987:479-483 for the high performance liquid chromatography (HPLC detection, two more clean up methods were evaluated. In all of them PEC.TOX.063 detection procedure was carried out. PEC.TOX.063 used for the clean up an in house column chromatography prepared with charcoal-alumina-celite (7+5+3 . Extraction was performed using acetonitrile- water (84+16 and an aliquot of the extract was passed through the column. Extract was dryed under vacuum and DON detected by HPLC using photodiode array detector. For the method that used immunoaffinity columns, water was the extraction solvent, and manufacture protocol was followed up. An aliquot of the extract was passed through the column. Column was washed using water and DON eluated using methanol 100%. For the method that used Strata X column for the clean up, the

  14. 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...

  15. (Contaminated soil)

    Energy Technology Data Exchange (ETDEWEB)

    Siegrist, R.L.

    1991-01-08

    The traveler attended the Third International Conference on Contaminated Soil, held in Karlsruhe, Germany. The Conference was a status conference for worldwide research and practice in contaminated soil assessment and environmental restoration, with more than 1500 attendees representing over 26 countries. The traveler made an oral presentation and presented a poster. At the Federal Institute for Water, Soil and Air Hygiene, the traveler met with Dr. Z. Filip, Director and Professor, and Dr. R. Smed-Hildmann, Research Scientist. Detailed discussions were held regarding the results and conclusions of a collaborative experiment concerning humic substance formation in waste-amended soils.

  16. Land application of tylosin and chlortetracycline swine manure: Impacts to soil nutrients and soil microbial community structure.

    Science.gov (United States)

    Stone, James J; Dreis, Erin K; Lupo, Christopher D; Clay, Sharon A

    2011-01-01

    The land application of aged chortetracycle (CTC) and tylosin-containing swine manure was investigated to determine associated impacts to soil microbial respiration, nutrient (phosphorus, ammonium, nitrate) cycling, and soil microbial community structure under laboratory conditions. Two silty clay loam soils common to southeastern South Dakota were used. Aerobic soil respiration results using batch reactors containing a soil-manure mixture showed that interactions between soil, native soil microbial populations, and antimicrobials influenced CO(2) generation. The aged tylosin treatment resulted in the greatest degree of CO(2) inhibition, while the aged CTC treatment was similar to the no-antimicrobial treatment. For soil columns in which manure was applied at a one-time agronomic loading rate, there was no significant difference in soil-P behavior between either aged CTC or tylosin and the no-antimicrobial treatment. For soil-nitrogen (ammonium and nitrate), the aged CTC treatment resulted in rapid ammonium accumulation at the deeper 40cm soil column depth, while nitrate production was minimal. The aged CTC treatment microbial community structure was different than the no-antimicrobial treatment, where amines/amide and carbohydrate chemical guilds utilization profile were low. The aged tylosin treatment also resulted in ammonium accumulation at 40 cm column depth, however nitrate accumulation also occurred concurrently at 10 cm. The microbial community structure for the aged tylosin was also significantly different than the no-antimicrobial treatment, with a higher degree of amines/amides and carbohydrate chemical guild utilization compared to the no-antimicrobial treatment. Study results suggest that land application of CTC and tylosin-containing manure appears to fundamentally change microbial-mediated nitrogen behavior within soil A horizons.

  17. Refreshment topics II: Design of distillation columns

    Directory of Open Access Journals (Sweden)

    Milojević Svetomir

    2006-01-01

    Full Text Available For distillation column design it is necessary to define all the variable parameters such as component concentrations in different streams temperatures, pressures, mass and energy flow, which are used to represent the separation process of some specific system. They are related to each other according to specific laws, and if the number of such parameters exceeds the number of their relationships, in order to solve a problem some of them must be specified in advance or some constraints assumed for the mass balance, the balance of energy, phase equilibria or chemical equilibria. Knowledge of specific elements which are the constituents of a distillation unit must be known to define the number of design parameters as well as some additional apparati also necessary to realize the distilation. Each separate apparatus might be designed and constructed only if all the necessary and variable parameters for such a unit are defined. This is the right route to solve a distilation unit in many different cases. The construction of some distillation unit requires very good knowledge of mass, heat and momentum transfer phenomena. Moreover, the designer needs to know which kind of apparatus will be used in the distillation unit to realize a specific production process. The most complicated apparatus in a rectification unit is the distillation column. Depending on the complexity of the separation process one, two or more columns are often used. Additional equipment are heat exchangers (reboilers, condensers, cooling systems, heaters, separators, tanks for reflux distribution, tanks and pumps for feed transportation, etc. Such equipment is connected by pipes and valves, and for the normal operation of a distillation unit other instruments for measuring the flow rate, temperature and pressure are also required. Problems which might arise during the determination and selection of such apparati and their number requires knowledge of the specific systems which must

  18. Strengthening of Steel Columns under Load: Torsional-Flexural Buckling

    Directory of Open Access Journals (Sweden)

    Martin Vild

    2016-01-01

    Full Text Available The paper presents experimental and numerical research into the strengthening of steel columns under load using welded plates. So far, the experimental research in this field has been limited mostly to flexural buckling of columns and the preload had low effect on the column load resistance. This paper focuses on the local buckling and torsional-flexural buckling of columns. Three sets of three columns each were tested. Two sets corresponding to the base section (D and strengthened section (E were tested without preloading and were used for comparison. Columns from set (F were first preloaded to the load corresponding to the half of the load resistance of the base section (D. Then the columns were strengthened and after they cooled, they were loaded to failure. The columns strengthened under load (F had similar average resistance as the columns welded without preloading (E, meaning the preload affects even members susceptible to local buckling and torsional-flexural buckling only slightly. This is the same behaviour as of the tested columns from previous research into flexural buckling. The study includes results gained from finite element models of the problem created in ANSYS software. The results obtained from the experiments and numerical simulations were compared.

  19. Enhanced reductive dechlorination in columns treated with edible oil emulsion

    Science.gov (United States)

    Long, Cameron M.; Borden, Robert C.

    2006-09-01

    The effect of edible oil emulsion treatment on enhanced reductive dechlorination was evaluated in a 14 month laboratory column study. Experimental treatments included: (1) emulsified soybean oil and dilute HCl to inhibit biological activity; (2) emulsified oil only; (3) emulsified oil and anaerobic digester sludge; and (4) continuously feeding soluble substrate. A single application of emulsified oil was effective in generating strongly reducing, anaerobic conditions for over 14 months. PCE was rapidly reduced to cis-DCE in all three live columns. Bioaugmentation with a halorespiring enrichment culture resulted in complete dechlorination of PCE to ethene in the soluble substrate column (yeast extract and lactate). However, an additional treatment with a pulse of yeast extract and bioaugmentation culture was required to stimulate complete dechlorination in the emulsion treated columns. Once the dechlorinating population was established, the emulsion only column degraded PCE from 90-120 μM to below detection with concurrent ethene production in a 33 day contact time. The lower biodegradation rates in the emulsion treated columns compared to the soluble substrate column suggest that emulsified oil barriers may require a somewhat longer contact time for effective treatment. In the HCl inhibited column, partitioning of PCE to the retained oil substantially delayed PCE breakthrough. However, reduction of PCE to more soluble degradation products ( cis-DCE, VC and ethene) greatly reduced the impact of oil-water partitioning in live columns. There was only a small decline in the hydraulic conductivity ( K) of column #1 (low pH + emulsion, Kfinal/ Kinitial = 0.57) and column #2 (live + emulsion, Kfinal/ Kinitial = 0.73) indicating emulsion injection did not result in appreciable clogging of the clayey sand. However, K loss was greater in column #3 (sludge +emulsion, Kfinal/ Kinitial = 0.12) and column #4 (soluble substrate, Kfinal/ Kinitial = 0.03) indicating clogging due

  20. Leaching of oxadyxil and tebuconazole in Colombian soil.

    Science.gov (United States)

    Aldana, M; De Prado, R; Martínez, M J

    2011-01-01

    Lake Tota (Boyaca, Colombia) supplies water for human consumption, agriculture and industry for more than 500.000 people. Oxadixyl and Tebuconazole are fungicides used in onion crops in the lake catchment area. The mobility of pesticides in soil, bioavailability and transfer to other environmental compartments depend on sorption and desorption kinetics and mechanisms. An understanding of these processes is essential for transport modeling and the rational design of corrective measures against pollution. A displacement study was performed on a hand packed soil column in laboratory conditions. A pulse of 0,01 M CaCl2 solution, containing a tracer (Bromide) and the fungicides Oxadixyl y Tebuconazole, was injected. Column experiment was performed at 0.078 cmh(-1) flow rate under unsaturated conditions. Eluates were collected in flasks at constant intervals and the volumes of eluate were recorded. After rainfall simulation, the soil from the column was sliced into six successive sections (5 cm). Methanol extraction was used to determine the fungicide in each soil section. Samples were measured by HPLC. Only Oxadixyl was recovered in leachates. Unlike bromide breakthrough curve, Oxadixyl was asymmetrical, with early breakthrough and increased tailing. The percentage eluted was 96.7% after ten pore volumes. Tebuconazole showed the highest retention in the first five cm of soil layer. The results suggest that oxadyxil presents highs risk to leachate through the soil profile and that Tebuconazole is strongly absorbed in Colombian soil.

  1. Experimental validation of pulsed column inventory estimators

    Energy Technology Data Exchange (ETDEWEB)

    Beyerlein, A.L.; Geldard, J.F. (Clemson Univ., SC (United States)); Weh, R. (Gesellschaft fuer Nuklear-Service mbH, Hannover (Germany)); Eiben, K.; Dander, T. (Wiederaufbereitungsanlage Karlsruhe Betriebsgesellschaft mbH (WAK), Eggenstein-Leopoldshafen (Germany)); Hakkila, E.A. (Los Alamos National Lab., NM (United States))

    1991-01-01

    Near-real-time accounting (NRTA) for reprocessing plants relies on the timely measurement of all transfers through the process area and all inventory in the process. It is difficult to measure the inventory of the solvent contractors; therefore, estimation techniques are considered. We have used experimental data obtained at the TEKO facility in Karlsruhe and have applied computer codes developed at Clemson University to analyze this data. For uranium extraction, the computer predictions agree to within 15% of the measured inventories. We believe this study is significant in demonstrating that using theoretical models with a minimum amount of process data may be an acceptable approach to column inventory estimation for NRTA. 15 refs., 7 figs.

  2. Maximum Variance Hashing via Column Generation

    Directory of Open Access Journals (Sweden)

    Lei Luo

    2013-01-01

    item search. Recently, a number of data-dependent methods have been developed, reflecting the great potential of learning for hashing. Inspired by the classic nonlinear dimensionality reduction algorithm—maximum variance unfolding, we propose a novel unsupervised hashing method, named maximum variance hashing, in this work. The idea is to maximize the total variance of the hash codes while preserving the local structure of the training data. To solve the derived optimization problem, we propose a column generation algorithm, which directly learns the binary-valued hash functions. We then extend it using anchor graphs to reduce the computational cost. Experiments on large-scale image datasets demonstrate that the proposed method outperforms state-of-the-art hashing methods in many cases.

  3. Permutation Analysis of Track and Column Braiding

    Institute of Scientific and Technical Information of China (English)

    李毓陵; 丁辛; 胡良剑

    2004-01-01

    The positions of braiding carrier in track and column braiding are represented by a diagrammatic braiding plan and a corresponding lattice-array is defined. A set is then formed so that the permutation analysis can be performed to represent the movement of carriers in a braiding process. The process of 4-step braiding is analyzed as an example to describe the application of the proposed method by expressing a braiding cycle as a product of disjoint cycles. As a result, a mapping relation between the disjoint cycles and the movement of carriers is deduced. Following the same analysis principles, a process of 8-step braiding and the corresponding initial state of the lattice-array is developed. A successful permutation analysis to the process manifests the general suitability of the proposed method.

  4. Education and training column: the learning collaborative.

    Science.gov (United States)

    MacDonald-Wilson, Kim L; Nemec, Patricia B

    2015-03-01

    This column describes the key components of a learning collaborative, with examples from the experience of 1 organization. A learning collaborative is a method for management, learning, and improvement of products or processes, and is a useful approach to implementation of a new service design or approach. This description draws from published material on learning collaboratives and the authors' experiences. The learning collaborative approach offers an effective method to improve service provider skills, provide support, and structure environments to result in lasting change for people using behavioral health services. This approach is consistent with psychiatric rehabilitation principles and practices, and serves to increase the overall capacity of the mental health system by structuring a process for discovering and sharing knowledge and expertise across provider agencies. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  5. Near shore floating oscillating wave column

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    Three different types of floating buoys, using oscillating wave columns, have been considered for generating electric power in an Atlantic environment. The study considered the situation close to the shore, but in the ultimate it was hoped to deploy units offshore. Although other designs would have greater power capture efficiency, the Spar Buoy was studied in greatest depth as it was expected to have the edge in terms of building cost and operating economics. A risk assessment was carried out for both concrete and steel buoys. The report covers (1) history of the project development; (2) project definition; (3) power generation and sensitivities and (4) lessons learned. The study was sponsored by Great Britain's DTI.

  6. Column: Putting the Science in Digital Forensics

    Directory of Open Access Journals (Sweden)

    Fred Cohen

    2011-03-01

    Full Text Available In a recent study, digital forensics was found to lack a consensus around even the most basis notions and terminology of the field. To quote: “These two preliminary studies individually suggest that scientific consensus in the area of digital forensic evidence examination is lacking in the broad sense, but that different groups within that overall community may have limited consensus around areas in which they have special expertise, and that the current peerreviewed publication process is not acting to bring about the sorts of elements typically found in the advancement of a science toward such a consensus. ... perhaps the most significant challenge may be in the development of a common language to describe the field...”(see PDF for full column

  7. The vertebral column of Australopithecus sediba.

    Science.gov (United States)

    Williams, Scott A; Ostrofsky, Kelly R; Frater, Nakita; Churchill, Steven E; Schmid, Peter; Berger, Lee R

    2013-04-12

    Two partial vertebral columns of Australopithecus sediba grant insight into aspects of early hominin spinal mobility, lumbar curvature, vertebral formula, and transitional vertebra position. Au. sediba likely possessed five non-rib-bearing lumbar vertebrae and five sacral elements, the same configuration that occurs modally in modern humans. This finding contrasts with other interpretations of early hominin regional vertebral numbers. Importantly, the transitional vertebra is distinct from and above the last rib-bearing vertebra in Au. sediba, resulting in a functionally longer lower back. This configuration, along with a strongly wedged last lumbar vertebra and other indicators of lordotic posture, would have contributed to a highly flexible spine that is derived compared with earlier members of the genus Australopithecus and similar to that of the Nariokotome Homo erectus skeleton.

  8. Influence of microsprinkler irrigation amount on water, soil, and pH profiles in a coastal saline soil.

    Science.gov (United States)

    Chu, Linlin; Kang, Yaohu; Wan, Shuqin

    2014-01-01

    Microsprinkler irrigation is a potential method to alleviate soil salinization. After conducting a homogeneous, highly saline, clayey, and coastal soil from the Bohai Gulf in northern China in a column experiment, the results show that the depth of the wetting front increased as the water amount applied increased, low-salinity and low-SAR enlarged after irrigation and water redistribution, and the soil pH increased with an increase in irrigation amount. We concluded that a water amount of 207 mm could be used to reclaim the coastal saline soil in northern China.

  9. Influence of Microsprinkler Irrigation Amount on Water, Soil, and pH Profiles in a Coastal Saline Soil

    Directory of Open Access Journals (Sweden)

    Linlin Chu

    2014-01-01

    Full Text Available Microsprinkler irrigation is a potential method to alleviate soil salinization. After conducting a homogeneous, highly saline, clayey, and coastal soil from the Bohai Gulf in northern China in a column experiment, the results show that the depth of the wetting front increased as the water amount applied increased, low-salinity and low-SAR enlarged after irrigation and water redistribution, and the soil pH increased with an increase in irrigation amount. We concluded that a water amount of 207 mm could be used to reclaim the coastal saline soil in northern China.

  10. Soil Water Retention Curve

    Science.gov (United States)

    Johnson, L. E.; Kim, J.; Cifelli, R.; Chandra, C. V.

    2016-12-01

    Potential water retention, S, is one of parameters commonly used in hydrologic modeling for soil moisture accounting. Physically, S indicates total amount of water which can be stored in soil and is expressed in units of depth. S can be represented as a change of soil moisture content and in this context is commonly used to estimate direct runoff, especially in the Soil Conservation Service (SCS) curve number (CN) method. Generally, the lumped and the distributed hydrologic models can easily use the SCS-CN method to estimate direct runoff. Changes in potential water retention have been used in previous SCS-CN studies; however, these studies have focused on long-term hydrologic simulations where S is allowed to vary at the daily time scale. While useful for hydrologic events that span multiple days, the resolution is too coarse for short-term applications such as flash flood events where S may not recover its full potential. In this study, a new method for estimating a time-variable potential water retention at hourly time-scales is presented. The methodology is applied for the Napa River basin, California. The streamflow gage at St Helena, located in the upper reaches of the basin, is used as the control gage site to evaluate the model performance as it is has minimal influences by reservoirs and diversions. Rainfall events from 2011 to 2012 are used for estimating the event-based SCS CN to transfer to S. As a result, we have derived the potential water retention curve and it is classified into three sections depending on the relative change in S. The first is a negative slope section arising from the difference in the rate of moving water through the soil column, the second is a zero change section representing the initial recovery the potential water retention, and the third is a positive change section representing the full recovery of the potential water retention. Also, we found that the soil water moving has traffic jam within 24 hours after finished first

  11. Study on the mechanism of transport of heavy metals in soil in western suburb of Beijing

    Institute of Scientific and Technical Information of China (English)

    LI Hongyan; WANG Jinsheng; TENG Yanguo; WANG Zhenyu

    2006-01-01

    Researchers are paying more and more attention to the adsorption and transport of heavy metals in soil. In this study, laboratory experiments were performed to investigate the characteristics of adsorption and transport of mercury in soils of different locations in the western suburb of Beijing. To characterize the adsorption mechanism of mercury in soil, adsorption isotherms were determined through a batch experiment. Soil column experiments were performed in saturated soil under steady-state flow at a specific water head. The breakthrough curves ( BTC ) for the tracer (bromine) and mercury were obtained after continuous input. Moreover, two solute transport models [ convection-dispersion equation model (CDE)and two-site non-equilibrium model (TSN) ] were used to simulate heavy metal movement in soil on a laboratory column scale. According to the simulating results, we explored which model is more adapted to simulate the movement of heavy metals in saturated soil in the western suburb of Beijing.

  12. Sewage sludge applied to agricultural soil: Ecotoxicological effects on representative soil organisms.

    Science.gov (United States)

    Carbonell, G; Pro, J; Gómez, N; Babín, M M; Fernández, C; Alonso, E; Tarazona, J V

    2009-05-01

    Application of sewage sludge to agricultural lands is a current practice in EU. European legislation permits its use when concentrations of metals in soil do not increase above the maximum permissible limits. In order to assess the fate and the effects on representative soil organisms of sewage sludge amendments on agricultural lands, a soil microcosm (multi-species soil system-MS3) experiment was performed. The MS3 columns were filled with spiked soil at three different doses: 30, 60 and 120tha(-1) fresh wt. Seed plants (Triticum aestivum, Vicia sativa and Brassica rapa) and earthworms (Eisenia fetida) were introduced into the systems. After a 21-d exposure period, a statistically significant increase for Cd, Cu, Zn and Hg concentrations was found for the soils treated with the highest application rate. Dose-related increase was observed for nickel concentrations in leachates. Plants and earthworm metal body burden offer much more information than metal concentrations and help to understand the potential for metal accumulation. Bioaccumulation factor (BAF(plant-soil)) presented a different behavior among species and large differences for BAF(earthworm-soil), from control or sewage-amended soil, for Cd and Hg were found. B. rapa seed germination was reduced. Statistically significant decrease in fresh biomass was observed for T. aestivum and V. sativa at the highest application rate, whereas B. rapa biomass decreased at any application rate. Enzymatic activities (dehydrogenase and phosphatase) as well as respiration rate on soil microorganisms were enlarged.

  13. Soil Solution

    NARCIS (Netherlands)

    Sonneveld, C.; Voogt, W.

    2009-01-01

    The characteristics of the soil solution in the root environment in the greenhouse industry differ much from those for field grown crops. This is caused firstly by the growing conditions in the greenhouse, which strongly differ from those in the field and secondly the function attributed to the soil

  14. Measurement of soil water potential over an extended range by polymer tensiometers: comparison with other instruments

    Science.gov (United States)

    van der Ploeg, M. J.; Gooren, H. P.; Hoogendam, R. C.; Bakker, G.; Huiskes, C.; Koopal, L. K.; Kruidhof, H.; de Rooij, G. H.

    2007-12-01

    .6% silt, 0.8% clay), and the other with loam (42.8% sand, 38.8% silt, 18.4% clay). The uniformly repacked soils were saturated at the beginning of the experiment, then drained, and left to dry out. Results show that polymer tensiometer data are comparable to the other instruments in their measurement ranges, and highlight the risks of converting water contents to matric potentials. This research is funded by the Dutch Technology Foundation (STW). Contributing companies are: ECO Ceramics BV (www.ecoceramics.nl), ENRIN (www.enrin.nl) and KELLER Meettechniek BV (www.keller-holland.nl).

  15. Linking soil biodiversity and agricultural soil management

    NARCIS (Netherlands)

    Thiele-Bruhn, S.; Bloem, J.; Vries, de F.T.; Kalbitz, K.; Wagg, C.

    2012-01-01

    Soil biodiversity vastly exceeds aboveground biodiversity, and is prerequisite for ecosystem stability and services. This review presents recent findings in soil biodiversity research focused on interrelations with agricultural soil management. Richness and community structure of soil biota depend o

  16. Linking soil biodiversity and agricultural soil management

    NARCIS (Netherlands)

    Thiele-Bruhn, S.; Bloem, J.; de Vries, F.T.; Kalbitz, K.; Wagg, C.

    2012-01-01

    Soil biodiversity vastly exceeds aboveground biodiversity, and is prerequisite for ecosystem stability and services. This review presents recent findings in soil biodiversity research focused on interrelations with agricultural soil management. Richness and community structure of soil biota depend

  17. Salt-Water Transport in Unsaturated Soils Under Crop Planting: Dynamics and Numerical Simulation

    Institute of Scientific and Technical Information of China (English)

    XU Li-Gang; YANG Jing-Song; ZHANG Qi; LIU Guang-Ming

    2005-01-01

    A laboratory salt-water dynamics experiment using unsaturated soils in packed silt loam and clay soil columns with different soil texture profiles and groundwater levels under crops were conducted to study the changes of salt-water dynamics induced by water uptake of crops and to propose the theoretical basis for the regulation and control of saltwater dynamics as well as to predict salinity levels. The HYDRUS 1D model was applied to simulate the one-dimensional movement of water and salt transport in the soil columns. The results showed that the salts mainly accumulated in the plow layer in the soil columns under crops. Soil water and salt both moved towards the plow layer due to soil water absorption by the crop root system. The salt contents in the column with lower groundwater were mostly greater than those with high groundwater. The water contents in the soil columns increased from top to the bottom due to plant root water uptake. The changes in groundwater level had little influence on water content of the root zone in the soil columns with crop planting. Comparison between the simulated and the determined values showed that model simulation results were ideal, so it is practicable to do numerical simulation of soil salt and water transport by the HYDRUS 1D model.Furthermore, if the actual movement of salt and water in fields is to be described in detail, much work needs to be done.The most important thing is to refine the parameters and select precise boundary conditions.

  18. Temperature-compensated 8-bit column driver for AMLCD

    Science.gov (United States)

    Dingwall, Andrew G. F.; Lin, Mark L.

    1995-06-01

    An all-digital, 5 V input, 50 Mhz bandwidth, 10-bit resolution, 128- column, AMLCD column driver IC has been designed and tested. The 10-bit design can enhance display definition over 6-bit nd 8-bit column drivers. Precision is realized with on-chip, switched-capacitor DACs plus transparently auto-offset-calibrated, opamp outputs. Increased resolution permits multiple 10-bit digital gamma remappings in EPROMs over temperature. Driver IC features include externally programmable number of output column, bi-directional digital data shifting, user- defined row/column/pixel/frame inversion, power management, timing control for daisy-chained column drivers, and digital bit inversion. The architecture uses fewer reference power supplies.

  19. Effect of axial mixing on RDC and PSE columns performance

    CERN Document Server

    Bastani, D

    2001-01-01

    Using the experimental data obtained from two RDC columns at two different sizes (7.62 and 21.9 cm) and one PSE column with 21.5 cm size, the effect of axial mixing on the performance of these columns was studied. Comparison between the experimental and theoretical (neglecting the axial mixing) number of transfer units indicates that, this effect in PSE columns is more than RDC columns (400% and 200% respectively). These results show that this effect can increase the height of the PSE column up to 4 times for a specific efficiency. Also the results show that this effect is more in law interfacial tension systems, which shows no need of application of agitation facilities when these systems are used.

  20. Multiple column high-throughput e-beam inspection (EBI)

    Science.gov (United States)

    Lam, David K.; Monahan, Kevin M.; Liu, Enden D.; Tran, Cong; Prescop, Ted

    2012-03-01

    Single-column e-beam systems are used in production for the detection of electrical defects, but are too slow to be used for the detection of small physical defects, and can't meet future inspection requirements. This paper presents a multiplecolumn e-beam technology for high throughput wafer inspection. Multibeam has developed all-electrostatic columns for high-resolution imaging. The elimination of magnetic coils enables the columns to be small; e-beam deflection is faster in the absence of magnetic hysteresis. Multiple miniaturecolumns are assembled in an array. An array of 100 columns covers the entire surface of a 300mm wafer, affording simultaneous cross-wafer sampling. Column performance simulations and system architecture are presented. Also provided are examples of high throughput, more efficient, multiple-column wafer inspection.

  1. Simulating a fuzzy level controller for flotation columns

    Institute of Scientific and Technical Information of China (English)

    Liao Yinfei; Liu Jiongtian; Wang Yongtian; Cao Yijun

    2011-01-01

    Level control in flotation columns is an important factor that influences the recovery and the grade of concentrate from the column.A flotation column is a nonlinear,multi-variable problem with changeable parameters that traditional methods have difficulty controlling.We have applied fuzzy control methods to the flotation column and tested the performance of the design by Matlab/Simulink simulation.The simulations show that level control in the flotation column becomes smoother and more rapid with the fuzzy controller.Compared to PID control methods the overshoot in valve position,the adjustment time,and the robustness of the controller are all improved.This indicates that it is suitable to model fuzzy controllers in applications for the study of automatic control of flotation column.

  2. Two-dimensional ion chromatography using tandem ion-exchange columns with gradient-pulse column switching.

    Science.gov (United States)

    Johns, Cameron; Shellie, Robert A; Pohl, Christopher A; Haddad, Paul R

    2009-10-09

    A two-dimensional ion chromatography (2D-IC) approach has been developed which provides greater resolution of complex samples than is possible currently using a single column. Two columns containing different stationary phases are connected via a tee-piece, which enables an additional eluent flow and independent control of eluent concentration on each column. The resultant mixed eluent flow at the tee-piece can be varied to produce a different eluent concentration on the second column. This allows analytes strongly retained on the first column to be separated rapidly on the second column, whilst maintaining a highly efficient, well resolved separation of analytes retained weakly on the first column. A group of 18 inorganic anions has been separated to demonstrate the utility of this approach and the proposed 2D-IC method provided separation of this mixture with resolution of all analytes greater than 1.3. Careful optimisation of the eluent profiles on both columns resulted in run times of less than 28 min, including re-equilibration. Separations were performed using isocratic or gradient elution on the first column, with an isocratic separation being used on the second column. Switching of the analytes onto the second column was performed using a gradient pulse of concentrated eluent to quickly elute strongly retained analytes from the first column onto the second column. The separations were highly repeatable (RSD of 0.01-0.12% for retention times and 0.08-2.9% for peak areas) and efficient (typically 8000-260,000 plates). Detection limits were 3-80 ppb.

  3. Carbon black retention in saturated natural soils: Effects of flow conditions, soil surface roughness and soil organic matter.

    Science.gov (United States)

    Lohwacharin, J; Takizawa, S; Punyapalakul, P

    2015-10-01

    We evaluated factors affecting the transport, retention, and re-entrainment of carbon black nanoparticles (nCBs) in two saturated natural soils under different flow conditions and input concentrations using the two-site transport model and Kelvin probe force microscopy (KPFM). Soil organic matter (SOM) was found to create unfavorable conditions for the retention. Despite an increased flow velocity, the relative stability of the estimated maximum retention capacity in soils may suggest that flow-induced shear stress forces were insufficient to detach nCB. The KPFM observation revealed that nCBs were retained at the grain boundary and on surface roughness, which brought about substantial discrepancy between theoretically-derived attachment efficiency factors and the ones obtained by the experiments using the two-site transport model. Thus, decreasing ionic strength and increasing solution pH caused re-entrainment of only a small fraction of retained nCB in the soil columns.

  4. A simulation-optimization model for Stone column-supported embankment stability considering rainfall effect

    Energy Technology Data Exchange (ETDEWEB)

    Deb, Kousik, E-mail: kousik@civil.iitkgp.ernet.in [Associate Professor, Department of Civil Engineering, IIT Kharagpur, Kharagpur-721302 (India); Dhar, Anirban, E-mail: anirban@civil.iitkgp.ernet.in [Assistant Professor, Department of Civil Engineering, IIT Kharagpur, Kharagpur-721302 (India); Purohit, Sandip, E-mail: sandip.purohit91@gmail.com [Former B.Tech Student, Department of Civil Engineering, NIT Rourkela, Rourkela (India)

    2016-02-01

    Landslide due to rainfall has been and continues to be one of the most important concerns of geotechnical engineering. The paper presents the variation of factor of safety of stone column-supported embankment constructed over soft soil due to change in water level for an incessant period of rainfall. A combined simulation-optimization based methodology has been proposed to predict the critical surface of failure of the embankment and to optimize the corresponding factor of safety under rainfall conditions using an evolutionary genetic algorithm NSGA-II (Non-Dominated Sorted Genetic Algorithm-II). It has been observed that the position of water table can be reliably estimated with varying periods of infiltration using developed numerical method. The parametric study is presented to study the optimum factor of safety of the embankment and its corresponding critical failure surface under the steady-state infiltration condition. Results show that in case of floating stone columns, period of infiltration has no effect on factor of safety. Even critical failure surfaces for a particular floating column length remain same irrespective of rainfall duration.

  5. A simulation-optimization model for Stone column-supported embankment stability considering rainfall effect

    Science.gov (United States)

    Deb, Kousik; Dhar, Anirban; Purohit, Sandip

    2016-02-01

    Landslide due to rainfall has been and continues to be one of the most important concerns of geotechnical engineering. The paper presents the variation of factor of safety of stone column-supported embankment constructed over soft soil due to change in water level for an incessant period of rainfall. A combined simulation-optimization based methodology has been proposed to predict the critical surface of failure of the embankment and to optimize the corresponding factor of safety under rainfall conditions using an evolutionary genetic algorithm NSGA-II (Non-Dominated Sorted Genetic Algorithm-II). It has been observed that the position of water table can be reliably estimated with varying periods of infiltration using developed numerical method. The parametric study is presented to study the optimum factor of safety of the embankment and its corresponding critical failure surface under the steady-state infiltration condition. Results show that in case of floating stone columns, period of infiltration has no effect on factor of safety. Even critical failure surfaces for a particular floating column length remain same irrespective of rainfall duration.

  6. Influence of foundation settlements in load redistribution on columns in a monitoring construction - Case Study

    Directory of Open Access Journals (Sweden)

    G. Savaris

    Full Text Available The objective of this article is to present the results obtained in a study on the interaction between the behavior of the structure and the foundation settlements and verify the influence of normal load distribution on the columns. In this mechanism, known as structure soil interaction (SSI, as the building is constructed, a transfer of loads occurs from the columns which tend to settle more to those that tend to settle less. The study was conducted in a building which had its settlements monitored from the beginning of construction. For this purpose, a linear tridimensional numerical model was constructed and numerical analysis was performed, using the finite elements method. In these analyses, numerical models corre- sponding to the execution of each floor were used, considering the settlements measured in each stage of the construction. The results of analy- ses showed that the effect of SSI are significant for calculating the normal efforts on the columns, particularly on those located in the first floors.

  7. [Characteristics of Adsorption Leaching and Influencing Factors of Dimethyl Phthalate in Purple Soil].

    Science.gov (United States)

    Wang, Qiang; Song, Jiao-yan; Zeng, Wei; Wang, Fa

    2016-02-15

    The typical soil-purple soil in Three Gorges Reservoir was the tested soil, the characteristics of adsorption leaching of dimethyl phthalate (DMP) in contaminated water by the soil, and the influencing factors in the process were conducted using soil column leaching experiment. The results showed that the parabolic equation was the best equation describing adsorption kinetics of DMP by soils. The concentration of DMP in the leaching solution had significant effect on the adsorption amounts of DMP. With the increasing concentration of DMP in the leaching solution, the adsorption capacities of DMP by purple soil increased linearly. The ionic strength and pH in leaching solution had significant effects on adsorption of DMP. On the whole, increasing of the ionic strength restrained the adsorption. The adsorption amounts at pH 5.0-7.0 were more than those under other pH condition. The addition of exogenous organic matter (OM) in purple soil increased the adsorption amount of DMP by purple soil. However, the adsorption amount was less than those with other addition amounts of exogenous OM when the addition of exogenous OM was too high (> or = 30 g x kg(-1)). The addition of surfactant sodium dodecylbenzene sulfonic acid (SDBS) in purple soil increased the adsorption amount of DMP by purple soil. The adsorption amount was maximal when the addition amount of SDBS was 50 mg x kg(-1). However, the adsorption amounts decreased with increasing addition amounts of SDBS although the adsorption amounts were still more than that of the control group, and the adsorption amount was almost equal to that of the control group when the addition amount of SDBS was 800 mg x kg(-1). Continuous leaching time affected the vertical distribution of DMP in the soil column. When the leaching time was shorter, the upper soil column adsorbed more DMP, while the DMP concentrations in upper and lower soil columns became similar with the extension of leaching time.

  8. Field-lysimeter and Column Studies As Complementary Survey Tools For Monitored Natural Attenuation (mna)

    Science.gov (United States)

    Totsche, K. U.; Hensel, D.; Jann, S.; Jaesche, P.; Kögel-Knabner, I.; Scheibke, R.

    The contamination of the unsaturated soil zone with organic pollutants (PAH, BTEX, PCB, Phenols, etc.) and pollutant mixtures, e.g. light/dense non-aqueous phase liq- uids (L/D-NAPLs), represents a specific challenge for sanitation and remediation of contaminated sites. Monitored natural attenuation as an alternative option for remedi- ation of such sites requires (1) the proof of an effective pollutant reduction potential and (2) the proof that a further spreading of the contaminants and their potentially toxic metabolites is minimized to an acceptable minimum concentration level. These demands apply equally likely to contaminated