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Sample records for column displacement experiments

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  2. A multi-flowpath model for the interpretation of immiscible displacement experiments in heterogeneous soil columns.

    PubMed

    Aggelopoulos, C A; Tsakiroglou, C D

    2009-04-01

    This work focuses on the phenomenon of the immiscible two-phase flow of water and oil in saturated heterogeneous soil columns. The goal is to develop a fast and reliable method for quantifying soil heterogeneities for incorporation into the relevant capillary pressure and relative permeability functions. Such data are commonly used as input data in simulators of contaminant transport in the subsurface. Rate-controlled drainage experiments are performed on undisturbed soil columns and the transient response of the axial distribution of water saturation is determined from electrical measurements. The transient responses of the axial distribution of water saturation and total pressure drop are fitted with the multi-flowpath model (MFPM) where the pore space is regarded as a system of parallel paths of different permeability. The MFPM enables us to quantify soil heterogeneity at two scales: the micro-scale parameters describe on average the effects of pore network heterogeneities on the two-phase flow pattern; the macro-scale parameters indicate the variability of permeability at the scale of interconnected pore networks. The capillary pressure curve is consistent with that measured with mercury intrusion porosimetry over the low pressure range. The oil relative permeability increases sharply at a very low oil saturation (<10(-3)) and tends to a high end value. The water relative permeability decreases abruptly at a low oil saturation (~0.1), whereas the irreducible wetting phase saturation is quite high. The foregoing characteristics of the two-phase flow properties are associated with critical (preferential) flowpaths that comprise a very small percentage of the total pore volume, control the overall hydraulic conductivity, and are consistent with the very broad range of pore-length scales usually probed in soil porous matrix.

  3. A Column Dispersion Experiment.

    ERIC Educational Resources Information Center

    Corapcioglu, M. Y.; Koroglu, F.

    1982-01-01

    Crushed glass and a Rhodamine B solution are used in a one-dimensional optically scanned column experiment to study the dispersion phenomenon in porous media. Results indicate that the described model gave satisfactory results and that the dispersion process in this experiment is basically convective. (DC)

  4. An Undergraduate Column Chromatography Experiment.

    ERIC Educational Resources Information Center

    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)

  5. NONEQUILIBRIUM SORPTION DURING DISPLACEMENT OF HYRDOPHOBIC ORGANIC CHEMICALS AND 45CA THROUGH SOIL COLUMNS WITH AQUEOUS AND MIXED SOLVENTS

    EPA Science Inventory

    A series of miscible displacement experiments was conducted to investigate the significance of intraorganic matter diffusion (IOMD) as the rate-limiting step in sorption of organic and inorganic solutes during steady water flow in soil columns. Displacement studies were performed...

  6. Reduction of the posterior column in displaced acetabulum fractures through the anterior intrapelvic approach.

    PubMed

    Kistler, Brian J; Sagi, H Claude

    2015-02-01

    The anterior intrapelvic approach can be used for the reduction and fixation of displaced fractures of the acetabulum. Reduction techniques and options for placement of fixation deviate to some degree from those used with the traditional ilioinguinal approach secondary to the surgeon's perspective and available vectors. Here, we present several techniques for the application of reduction clamps, reduction techniques, and fixation options for the posterior column in displaced fractures of the acetabulum treated through the anterior intrapelvic approach.

  7. Commander prepares glass columns for electrophoresis experiment

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Commander Jack Lousma prepares on of the glass columns for the electrophoresis test in the middeck area of the Columbia. The experiment, deployed in an L-shaped mode in upper right corner, consists of the processing unit with glass columns in which the separation takes place; a camera (partially obscurred by Lousma's face) to document the process; and a cryogenic freezer to freeze and store the samples after separation.

  8. Seismic Behavior and Force-Displacement Characterization of Neotype Column-Slab High Piers

    PubMed Central

    Zhou, YanQun; Zhang, YeZhi; Ye, MeiXin; Zhan, MengSi

    2014-01-01

    The seismic behavior and plasticity spreading of a neotype column-slab high pier are researched in this paper. Four scale model tests of a web slab with two boundary columns are carried out under cyclic inelastic lateral displacements simulating seismic response. The test results show that the neotype column-slab high pier has strong and stable bearing capacity, good ductility, and energy dissipation capacity. The experimental values pertaining to the spread of plasticity are derived. An approach for deriving the spread of plasticity analytically is deduced and applied to the four tests. This method accurately assesses a pier's spread of plasticity for most ductility levels. At nearly all ductility levels, the mean difference between analytical assessments of the spread of plasticity and results from 4 large-scale tests is 12% with a 9% coefficient of variation. PMID:24883420

  9. Modified ilioinguinal approach in combined surgical exposures for displaced acetabular fractures involving two columns.

    PubMed

    Wang, Peng; Zhu, Xiaodong; Xu, Peng; Zhang, Yan; Wang, Lubo; Liu, Xiangyan; Mu, Weidong

    2016-01-01

    The purpose of this study is to assess the advantages of modified ilioinguinal approach in combined surgical exposures for displaced acetabular fractures involving two columns management. 73 patients with displaced acetabular fractures involving two columns underwent open reduction and internal fixation through combined surgical approaches between 2006 and 2014 in our hospital. The modified ilioinguinal approach combined with Kocher-Langenbeck approach group (group A) included 46 patients. The standard ilioinguinal approach combined with Kocher-Langenbeck approach group (group B) included 27 patients. Outcome was assessed in operative time, blood loss, function outcomes and complications. In group A, the average operative time was 123.2 min, and the average blood loss was 586.2 ml. Anatomic reduction was achieved in 39 patients (84.8 %). The functional recovery was good in 37 patients (80.4 %). Complications related to the approach were observed in 10 patients (21.7 %). In group B, the average operative time was 161.5 min, and the average blood loss was 830 ml. Anatomic reduction was achieved in 24 patients (88.9 %). The functional recovery was good in 22 patients (81.5 %). Complications related to the approach were observed in 9 patients (33.3 %). This study demonstrates that both combined approaches permits good postoperative function results for treatment of acetabular fractures involving two columns. However, the modified ilioinguinal approach combined with Kocher-Langenbeck approach provides less operative time, blood loss and complications. PMID:27652175

  10. COLUMN EXPERIMENTS AND ANOMALOUS CONDUCTIVITY IN HYDROCARBON-IMPACTED SOILS

    EPA Science Inventory

    A laboratory experiment was designed to increase the understanding of the geoelectric effects of microbial " degradation of hydrocarbons. Eight large columns were were paired to provide a replicate of each of four experiments. These large-volume columns contained "sterilized" soi...

  11. Mini-columns for Conducting Breakthrough Experiments. Design and Construction

    SciTech Connect

    Dittrich, Timothy M.; Reimus, Paul William; Ware, Stuart Douglas

    2015-06-11

    Experiments with moderately and strongly sorbing radionuclides (i.e., U, Cs, Am) have shown that sorption between experimental solutions and traditional column materials must be accounted for to accurately determine stationary phase or porous media sorption properties (i.e., sorption site density, sorption site reaction rate coefficients, and partition coefficients or Kd values). This report details the materials and construction of mini-columns for use in breakthrough columns to allow for accurate measurement and modeling of sorption parameters. Material selection, construction techniques, wet packing of columns, tubing connections, and lessons learned are addressed.

  12. Calcium nitrate miscible displacement at different concentrations in packed soil columns

    NASA Astrophysics Data System (ADS)

    Previatello da Silva, Livia; Alves de Oliveira, Luciano; Honorio de Miranda, Jarbas

    2015-04-01

    Studies on miscible displacement provide us with rational means to understand the important physical phenomena involved leaching in soils, fertilizers, movement of ions and other similar processes. With current environmental concerns and the need to understand the processes that govern movement of water and solutes in soil, studies are needed to allow increasing the efficiency of input use in agriculture that somehow can mitigate the impact of activities of this sector on groundwater contamination. Contamination of soil and groundwater and surface water in areas with fertilizer application and reuse of effluent is closely linked to materials chemical characteristics, and retention and transmission of water and soil solutes. Solute mobility in soil is inversely related to their adsorption to solid fraction or to environmental conditions that favor ions precipitation. Ion adsorption to soil exchange complex makes ion maintains exchange with the soil solution, providing once their retention by the solid fraction, another its availability in aqueous medium. Nitrate leaching is a physical phenomenon, favored by low energy involved in adsorption to soil particles and also by its high solubility in water. This high solubility and the weak interaction with soil matrix to allow anion follow the wetting front. Therefore, the objective was determine nitrate transport parameters in soil, through Breakthrough Curves (BTC) development under conditions of disturbed soil samples (saturated soil and steady state conditions) in columns (20.0 cm in height and 5 cm in diameter), by calcium nitrate solution application at two concentrations, 50 and 130 g m-3 NO3-, in two tropical soil types, Yellow Oxisol (S1) and Anfisol (S2). Research was carried out in laboratory. Transport parameters for both soils and nitrate concentrations were obtained by numerical fit using STANMOD software, by the inverse modelling. Results showed predominance of convective transport in S1, which had a higher

  13. Plasma column displacement measurements by modified Rogowski sine-coil and Biot-Savart/magnetic flux equation solution on IR-T1 tokamak

    SciTech Connect

    Razavi, M.; Mollai, M.; Khorshid, P.; Nedzelskiy, I.; Ghoranneviss, M.

    2010-05-15

    The modified Rogowski sine-coil (MRSC) has been designed and implemented for the plasma column horizontal displacement measurements on small IR-T1 tokamak. MRSC operation has been examined on test assembly and tokamak. Obtained results show high sensitivity to the plasma column horizontal displacement and negligible sensitivity to the vertical displacement; linearity in wide, {+-}0.1 m, range of the displacements; and excellent, 1.5%, agreement with the results of numerical solution of Biot-Savart and magnetic flux equations.

  14. Column experiments on organic micropollutants - applications and limitations

    NASA Astrophysics Data System (ADS)

    Banzhaf, Stefan; Hebig, Klaus

    2016-04-01

    As organic micropollutants become more and more ubiquitous in the aquatic environment, a sound understanding of their fate and transport behaviour is needed. This is to assure both safe and clean drinking water supply for mankind in the future and to protect the aquatic environment from pollution and negative consequences caused by manmade contamination. Apart from countless field studies, column experiments were and are frequently used to study transport of organic micropollutants. As the transport of (organic) solutes in groundwater is controlled by the chemical and physical properties of the compounds, the solvent (the groundwater including all solutes), and the substrate (the aquifer material), the adjustment and control of these boundary conditions allow to study a multitude of different experimental setups and to address specific research questions. The main purpose, however, remains to study the transport of a specific compound and its sorption and degradation behaviour in a specific sediment or substrate. Apart from the effective control of the individual boundary conditions, the main advantage of columns studies compared to other experimental setups (such as field studies, batch/microcosm studies), is that conservative and reactive solute breakthrough curves are obtained, which represent the sum of the transport processes. The analysis of these curves is well-developed and established. Additionally, limitations of this experimental method are presented here: the effects observed in column studies are often a result of dynamic, non-equilibrium processes. Time (or flow velocity) plays a major role in contrast to batch experiments, in which all processes will be observed until equilibrium is reached in the substrate-solution-system. Slightly modifying boundary conditions in different experiments have a strong influence on transport and degradation behaviour of organic micropollutants. This is a significant severe issue when it comes to general findings on the

  15. A Flexible Moisture Content Probe for Unsaturated Soil Column Experiments

    SciTech Connect

    E. D. Mattson; K. E. Baker; C. D. Palmer; J. M Svoboda

    2006-05-01

    A commercially available soil moisture capacitance probe was modified by replacing rigid electrode traces with non-intrusive, flexible circuit board trace electrodes that can be attached to the interior of soil column walls. This new design minimizes soil packing difficulties and potential bias in flow pathways commonly associated with rigid probe installations in column experiments. Testing showed that the modified probe design provides reproducible output independent of sample bulk density. The electrical conductivity of the pore-water solution, however, affects the probe response. For cases where the specific conductance of the pore-water solution is constant, the probe can be calibrated. The flexible electrodes offer a simple means of minimizing sensor intrusion into laboratory soil columns while providing reproducible voltage output that is a function of moisture content.

  16. Column Experiments to Interpret Weathering in Columbia Hills

    NASA Technical Reports Server (NTRS)

    Hausrath, E. M.; Morris, R.V.; Ming, D.W.; Golden, D.C.; Galindo, C.; Sutter, B.

    2009-01-01

    Phosphate mobility has been postulated as an indicator of early aqueous activity on Mars. In addition, rock surfaces analyzed by the Mars Exploration Rover Spirit are consistent with the loss of a phosphate- containing mineral To interpret phosphate alteration behavior on Mars, we performed column dissolution experiments leaching the primary phases Durango fluorapatite, San Carlos olivine, and basalt glass (Stapafjell Volcano, courtesy of S. Gislason, University of Iceland) [3,4]) with acidic solutions. These phases were chosen to represent quickly dissolving phases likely present in Columbia Hills. Column dissolution experiments are closer to natural dissolution conditions than batch experiments, although they can be difficult to interpret. Acidic solutions were used because the leached layers on the surfaces of these rocks have been interpreted as resulting from acid solutions [5].

  17. Distillation column for the XENON1T experiment

    NASA Astrophysics Data System (ADS)

    Fieguth, Alexander; XENON Collaboration

    2016-05-01

    The XENON1T experiment will probe a new parameter space in the direct dark matter search. Besides the enlargement of target mass to the ton scale, a further background reduction with respect to its predecessor XENON100 is necessary. A major contribution to the intrinsic contamination is the β-decaying isotope 85Kr, which leads to the requirement of a concentration less than 0.2 ppt of natural krypton in xenon. Its removal from the xenon gas is achieved by cryogenic distillation. For the new experiment a custom-build distillation column with a separation factor larger than 105 and a throughput of 3kg/h has been designed and built at the University of Muenster. Furthermore its performance has been characterized using different trace gas detection techniques, e.g. a novel 83mKr-tracer method, and its functionality has been tested successfully. The distillation column, which is installed and commissioned at the XENON1T experiment, is ready to process the 3.5 tons of xenon.

  18. Early experience with reduction of displaced disruption of the pelvic ring using a pelvic reduction frame.

    PubMed

    Lefaivre, K A; Starr, A J; Barker, B P; Overturf, S; Reinert, C M

    2009-09-01

    We describe our early operative experience with a new pelvic reduction frame and the standard of reduction of fractures of the pelvic ring which we achieved in the first 35 consecutive patients, with 34 acute fractures and one nonunion. The pre-operative and immediate post-operative radiographs were measured, using two methods, to find the maximum radiological displacement of the fracture and the quality of the reduction according to the criteria of Tornetta and Matta. There were 19 vertical shear fractures and 16 compression injuries. The mean age of the patients was 33.5 years (10 to 59) and mean delay to surgery was 4.6 days (0 to 16) in the 34 acute injuries. The mean operative time in isolated procedures was 103.4 minutes (SD 6.5). All but one patient had iliosacral screws implanted, 18 had screws in the anterior column, six had plates at the symphysis pubis and 12 had anterior external fixators. The mean maximum horizontal or vertical displacement was improved from 30.8 mm (SD 2.7) to a mean of 7.1 mm (SD 0.7). The reduction was assessed as excellent in ten patients, good in 18, and fair in the remainder. There was no significant influence on the quality of the reduction caused by obesity (p = 0.34), the type of fracture (p = 0.41) or delay to surgery (p = 0.83). The frame was shown to be effective, allowing the surgeon to obtain a satisfactory reduction and fixation of acute displaced disruptions of the pelvic ring.

  19. A cryogenic distillation column for the XENON1T experiment

    NASA Astrophysics Data System (ADS)

    Rosendahl, S.; Brown, E.; Cristescu, I.; Fieguth, A.; Huhmann, C.; Murra, M.; Weinheimer, C.

    2014-11-01

    The XENON collaboration aims for the direct detection of cold dark matter in form of weakly interacting massive particles (WIMPs). A dual phase time projection chamber filled with liquid xenon is used to detect the WIMP-nucleon interaction. For the next generation experiment XENON1T with an active target mass of 1 ton of xenon, a new distillation column to remove krypton out of xenon to a concentration of < 5 × 10-13 (0.5 ppt) natural krypton in xenon is designed and tested at the Institut für Kernphysik, Universitat Munster. The experimental setup together with two diagnostic tools is presented, as well as one stability test of a 11 hour distillation run at the designed flowrate of 3 kg per hour.

  20. Investigations of infiltration processes from flooded areas by column experiments

    NASA Astrophysics Data System (ADS)

    Mohrlok, U.; Bethge, E.; Golalipour, A.

    2009-04-01

    In case of inundation of flood plains during flood events there is an increased risk of groundwater contamination due to infiltration of increasingly polluted river water. Specifically in densely populated regions, this groundwater may be used as source for drinking water supply. For the evaluation of this a detailed quantitative understanding of the infiltration processes under such conditions is required. In this context the infiltration related to a flood event can be described by three phases. The first phase is defined by the saturation of the unsaturated soils. Within the second phase infiltration takes place under almost saturated conditions determined by the hydraulic load of the flood water level. The drainage of the soils due to falling groundwater table is characterizing the third phase. Investigations by soil columns gave a detailed insight into the infiltration processes caused by flooding. Inflow at the soil top was established by a fixed water table fed by a Mariotte bottle. Free outflow and a groundwater table were used as lower boundary condition. Inflow and outflow volume were monitored. The evolution of the matrix pressure was observed by micro-tensiometers installed at several depths within the soil column. The flow processes during phase one and two were characterized by a tracer test. Some of the experiments were repeated in order to study the influence of preliminary events. Main results were a difference in infiltration due to the lower boundary condition with regard to inflow rate, outflow dynamics and matrix pressure evolution which is directly related to the water content evolution. Further, the influence of preliminary events was different for the different boundary conditions. A replacement of pre-event water could be observed which was confirmed by volume balances calculated for the infiltration experiments. Although these water balances were almost closed significant dynamics of the matrix pressure remained in soil column in the

  1. Missed Opportunities: Examining the Literacy Experiences of African American Students Displaced by Hurricane Katrina

    ERIC Educational Resources Information Center

    Pollard, Tamica McClarty

    2011-01-01

    The purpose of this study was to examine how five African American middle school students, who were displaced by Hurricane Katrina represent their literacy experiences before, during, and after their displacement. Specifically, the two research questions were: (a) What are the stories that these middle school students tell about their lives,…

  2. Transport of bisphenol-A in sandy aquifer sediment: Column experiment.

    PubMed

    Zakari, Sissou; Liu, Hui; Tong, Lei; Wang, Yan; Liu, Jianfeng

    2016-02-01

    The present paper aims to study the transport behavior of bisphenol-A (BPA) in sandy aquifer so as to provide important parameters for the prediction and control of contaminant plume in aquifer. Miscible displacement experiments were conducted and the breakthrough curves (BTCs) were simulated using HYDRUS-1D software. The effects of pore-water velocity (10-52 cm h(-1)) and initial concentration (2.5-40 mg L(-1)) on the sorption were also investigated. The BTCs of BPA fit the linear first-order non-equilibrium two-site model. The parameters such as partition coefficient (K(d)), the fraction of instantaneous adsorption on "Type-1" sites (F), the first order sorption rate coefficient for the kinetic non-equilibrium (type-2) sites (α), the retardation coefficient (R), and sorption capacity (q(column)) were computed. Results showed that BPA transported 0.11-0.83 m with various pore water velocity in sandy sediment column when water flowed 1 m. The sorption of BPA was mainly caused by the instantaneous surface adsorption as F varied from 0.596 to 0.908. The transport velocity of BPA was affected by pore water velocity (v) and followed the linear equation 1/R = 0.0600 + 0.0110v (r(2) = 0.9724). The parameter K(d) were also closely related to v and followed the equation LnK(d) = 1.0023-0.0482v (r(2) = 0.9690). The sorption capacity was more related to the initial BPA concentration (C0) and followed the linear equation q(column) = 0.265 + 0.253C0 (r(2) = 0.9727). The parameter α was affected by both v and C0 whereas F was not dramatically affected by both. PMID:26539704

  3. Miscible fluid displacement stability in unconfined porous media:. Two-dimensional flow experiments and simulations

    NASA Astrophysics Data System (ADS)

    Jawitz, James W.; Annable, Michael D.; Rao, P. S. C.

    1998-06-01

    In situ flushing groundwater remediation technologies, such as cosolvent flushing, rely on the stability of the interface between the resident and displacing fluids for efficient removal of contaminants. Contrasts in density and viscosity between the resident and displacing fluids can adversely affect the stability of the displacement front. Petroleum engineers have developed techniques to describe these types of processes; however, their findings do not necessarily translate directly to aquifer remediation. The purpose of this laboratory study was to investigate how density and viscosity contrasts affected cosolvent displacements in unconfined porous media characterized by the presence of a capillary fringe. Two-dimensional flow laboratory experiments, which were partially scaled to a cosolvent flushing field experiment, were conducted to determine potential implications of flow instabilities in homogeneous sand packs. Numerical simulations were also conducted to investigate the differential impact of fluid property contrasts in unconfined and confined systems. The results from these experiments and simulations indicated that the presence of a capillary fringe was an important factor in the displacement efficiency. Buoyant forces can act to carry a lighter-than-water cosolvent preferentially into the capillary fringe during displacement of the resident groundwater. During subsequent water flooding, buoyancy forces can act to effectively trap the cosolvent in the capillary fringe, contributing to the inefficient removal of cosolvent from the aquifer.

  4. Field performance of the Walker Branch throughfall displacement experiment

    SciTech Connect

    Hanson, P.J.; Todd, D.E.; Edwards, N.T.; Huston, M.A.

    1994-10-06

    The authors are conducting a large-scale manipulative field experiments in an upland oak forest on the Walker Branch Watershed in eastern Tennessee USA to identify important ecosystem responses that might result from future precipitation changes. The manipulation of soil moisture is being implemented by a gravity-driven transfer of throughfall precipitation from one treatment plot to another. Throughfall is intercepted in {approx} 2,000 subcanopy troughs (0.3 x 5 m) suspended above the forest floor of the dry plots ({approx} 33% of the ground area is covered) and transferred by gravity flow across an ambient plot for subsequent distribution onto the wet treatment plot. Percent soil water is being monitored with time domain reflectometers at 310 sampling locations across the site. The experimental system is able to produce statistically significant differences in soil water content in years having both extremely dry and extremely wet conditions. Furthermore, comparisons of pre- and post-installation soil temperature measurements have documented the ability of the experimental design to produce these changes without changing the microclimate of the forest understory.

  5. Use of column experiments to investigate the fate of organic micropollutants - a review

    NASA Astrophysics Data System (ADS)

    Banzhaf, Stefan; Hebig, Klaus H.

    2016-09-01

    Although column experiments are frequently used to investigate the transport of organic micropollutants, little guidance is available on what they can be used for, how they should be set up, and how the experiments should be carried out. This review covers the use of column experiments to investigate the fate of organic micropollutants. Alternative setups are discussed together with their respective advantages and limitations. An overview is presented of published column experiments investigating the transport of organic micropollutants, and suggestions are offered on how to improve the comparability of future results from different experiments. The main purpose of column experiments is to investigate the transport and attenuation of a specific compound within a specific sediment or substrate. The transport of (organic) solutes in groundwater is influenced by the chemical and physical properties of the compounds, the solvent (i.e., the groundwater, including all solutes), and the substrate (the aquifer material). By adjusting these boundary conditions a multitude of different processes and related research questions can be investigated using a variety of experimental setups. Apart from the ability to effectively control the individual boundary conditions, the main advantage of column experiments compared to other experimental setups (such as those used in field experiments, or in batch microcosm experiments) is that conservative and reactive solute breakthrough curves can be derived, which represent the sum of the transport processes. There are well-established methods for analyzing these curves. The effects observed in column studies are often a result of dynamic, non-equilibrium processes. Time (or flow velocity) is an important factor, in contrast to batch experiments where all processes are observed until equilibrium is reached in the substrate-solution system. Slight variations in the boundary conditions of different experiments can have a marked influence on

  6. Tapped granular column dynamics: simulations, experiments and modeling

    NASA Astrophysics Data System (ADS)

    Rosato, A. D.; Zuo, L.; Blackmore, D.; Wu, H.; Horntrop, D. J.; Parker, D. J.; Windows-Yule, C.

    2016-07-01

    This paper communicates the results of a synergistic investigation that initiates our long term research goal of developing a continuum model capable of predicting a variety of granular flows. We consider an ostensibly simple system consisting of a column of inelastic spheres subjected to discrete taps in the form of half sine wave pulses of amplitude a/ d and period τ . A three-pronged approach is used, consisting of discrete element simulations based on linear loading-unloading contacts, experimental validation, and preliminary comparisons with our continuum model in the form of an integro-partial differential equation.

  7. Experiment K307: Vertebral body strength of rat spinal columns

    NASA Technical Reports Server (NTRS)

    Kazarian, L. E.

    1981-01-01

    The effects of space flight on vertebral body bone strength excised were investigated. Comparative biomechanical investigations of vertebral body strength for flight, synchronous, and vivarium rats following spacecraft recovery (R+0), at R+6 and R+29 days post flight recovery are presented. Statistical analyses are presented for the mechanical properties of stiffness, ultimate load, displacement to ultimate load, and energy to ultimate load. At R+0 all of the above properties show that the vertebral body exhibits an increasing susceptibility to fracture. The reduction of bone strength is inhomogeneous and dependent on vertebral level. The R+6 recovery data was inconclusive since it varied above and below the R+0 data. At R+29 ultimate load values showed a statistically significant increase in bone strength approaching that of the vivarium or control group.

  8. Life Experiences of Displaced Workers: From Closing Plants to Their Journey through Iowa Community Colleges

    ERIC Educational Resources Information Center

    Samuels, Anisha La Velle

    2010-01-01

    The purpose of this phenomenological study was to illuminate the life experiences of displaced workers enrolled in community colleges for retraining and their views on obtaining employment after completion of a degree. The study is important because it provides qualitative data that will inform community college academic leadership, faculty,…

  9. Applicability of soil column incubation experiments to measure CO2 efflux

    NASA Astrophysics Data System (ADS)

    Guo, Linlin; Nishimura, Taku; Imoto, Hiromi; Sun, Zhigang

    2015-10-01

    Accurate measurements of CO2 efflux from soils are essential to understand dynamic changes in soil carbon storage. Column incubation experiments are commonly used to study soil water and solute transport; however, the use of column incubation experiments to study soil CO2 efflux has seldom been reported. In this study, a 150-day greenhouse experiment with two treatments (no-tillage and tillage soils) was conducted to evaluate the applicability of soil column incubation experiments to study CO2 efflux. Both the chamber measurement and the gradient method were used, and results from the two methods were consistent: tillage increased soil cumulative CO2 efflux during the incubation period. Compared with fieldwork, incubation experiments can create or precisely control experimental conditions and thus have advantages for investigating the influence of climate factors or human activities on CO2 efflux. They are superior to bottle incubation because soil column experiments maintain a soil structure that is almost the same as that in the field, and thus can facilitate analyses on CO2 behaviour in the soil profile and more accurate evaluations of CO2 efflux. Although some improvements are still required for column incubation experiments, wider application of this method to study soil CO2 behaviour is expected.

  10. Adequacy of transport parameters obtained in soil column experiments for selected chemicals

    NASA Astrophysics Data System (ADS)

    Raymundo-Raymundo, E.; Nikolskii, Yu. N.; Guber, A. K.; Landeros-Sanchez, C.

    2012-07-01

    The transport parameters were determined for the 18O isotope (in the form of H2 18O), the Br- ion, and atrazine in intact columns of allophanic Andosol (Mexico State, Mexico). A one-dimensional model for the convective-dispersive transport of chemicals with account for the decomposition and equilibrium adsorption (HYDRUS-1D), which is widely applied for assessing the risk of the chemical and bacterial contamination of natural waters, was used. The model parameters were obtained by solving the inverse problem on the basis of laboratory experiments on the transport of the 18O isotope, the Br- ion, and atrazine in intact soil columns at a fixed filtration velocity. The hydrodynamic dispersion parameters determined for the 18O and Br- ions in one column were of the same order of magnitude, and those for atrazine were higher by 3-4 times. The obtained parameters were used to calculate the transport of these substances in another column with different values of the water content and filtration velocity. The transport process was adequately described only for the 18O isotope. In the case of the Br- ion, the model significantly underestimated the transport velocity; for atrazine, its peak concentration in the column was overestimated. The column study of the transport of the three chemical compounds showed that transport parameters could not be reliably predicted from the results of a single experiment, even when several compounds were used in this experiment.

  11. Mobility of pharmaceuticals carbamazepine, diclofenac, ibuprofen, and propyphenazone in miscible-displacement experiments

    NASA Astrophysics Data System (ADS)

    Scheytt, Traugott J.; Mersmann, Petra; Heberer, Thomas

    2006-02-01

    Many pharmaceuticals pass the unsaturated zone before reaching an aquifer. Therefore, laboratory sand column transport experiments were conducted to study the transport behavior of carbamazepine, diclofenac, ibuprofen, and propyphenazone under unsaturated conditions. The test water was artificial sewage effluent to simulate the infiltration of reused wastewater. The test water was spiked with the pharmaceutically active compounds and the tracer LiCl. Afterwards it was passed through laboratory sand columns, one experiment for each pharmaceutical. The physical and chemical parameters were recorded and general ions measured. Pharmaceuticals were measured using solid phase extraction, derivatization, and detection with GC-MS. The column experiments indicate a significant elimination of ibuprofen (54%), propyphenazone (55%), and diclofenac (35%), whereas carbamazepine was not eliminated. Retardation factors varied between 1.84 for carbamazepine, 2.51 for propyphenazone, 3.00 for ibuprofen, and 4.80 for diclofenac. These results show that mobility and elimination of diclofenac, ibuprofen, and propyphenazone is about in the same range as for experiments under saturated conditions whereas carbamazepine had a significantly lower sorption and elimination under unsaturated conditions.

  12. Effect of pore velocity on biodegradation of cis-dichloroethene (DCE) in column experiments.

    PubMed

    Mendoza-Sanchez, Itza; Autenrieth, Robin L; McDonald, Thomas J; Cunningham, Jeffrey A

    2010-06-01

    Column experiments were conducted to evaluate the effect of pore velocity on the extent of biodegradation of cis-dichloroethene (cis-DCE) during transport in porous media. Columns were filled with homogeneous glass beads and inoculated with a culture capable of complete dechlorination of tetrachloroethene to ethene. A constant concentration of cis-DCE was maintained in the columns' influent. Three different pore velocities were tested in duplicate, subjecting each column to a constant velocity. At high flow velocity, degradation of cis-DCE to ethene was nearly complete within the residence time of the columns. However, at medium and low flow velocities, incomplete dechlorination was observed. After 7 weeks, DNA was harvested from the columns to determine differences in the microbial populations. Results suggest that Dehalococcoides sp. were present in higher quantities in the high-velocity columns, consistent with the observed dechlorination. These results suggest that, at contaminated groundwater sites, heterogeneity of groundwater velocity may be one factor that contributes to heterogeneous distribution of biological activity.

  13. Design and Operation of Cryogenic Distillation Research Column for Ultra-Low Background Experiments

    NASA Astrophysics Data System (ADS)

    Chiller, Christopher; Alanson Chiller, Angela; Jasinski, Benjamin; Snyder, Nathan; Mei, Dongming

    2013-04-01

    Motivated by isotopically enriched germanium (76Ge and 73Ge) for monocrystalline crystal growth for neutrinoless double-beta decay and dark matter experiments, a cryogenic distillation research column was developed. Without market availability of distillation columns in the temperature range of interest with capabilities necessary for our purposes, we designed, fabricated, tested, refined and operated a two-meter research column for purifying and separating gases in the temperature range from 100-200K. Due to interest in defining stratification, purity and throughput optimization, capillary lines were integrated at four equidistant points along the length of the column such that real-time residual gas analysis could guide the investigation. Interior gas column temperatures were monitored and controlled within 0.1oK accuracy at the top and bottom. Pressures were monitored at the top of the column to four significant figures. Subsequent impurities were measured at partial pressures below 2E-8torr. We report the performance of the column in this paper.

  14. Effect of pore velocity on biodegradation of cis-dichloroethene (DCE) in column experiments.

    PubMed

    Mendoza-Sanchez, Itza; Autenrieth, Robin L; McDonald, Thomas J; Cunningham, Jeffrey A

    2010-06-01

    Column experiments were conducted to evaluate the effect of pore velocity on the extent of biodegradation of cis-dichloroethene (cis-DCE) during transport in porous media. Columns were filled with homogeneous glass beads and inoculated with a culture capable of complete dechlorination of tetrachloroethene to ethene. A constant concentration of cis-DCE was maintained in the columns' influent. Three different pore velocities were tested in duplicate, subjecting each column to a constant velocity. At high flow velocity, degradation of cis-DCE to ethene was nearly complete within the residence time of the columns. However, at medium and low flow velocities, incomplete dechlorination was observed. After 7 weeks, DNA was harvested from the columns to determine differences in the microbial populations. Results suggest that Dehalococcoides sp. were present in higher quantities in the high-velocity columns, consistent with the observed dechlorination. These results suggest that, at contaminated groundwater sites, heterogeneity of groundwater velocity may be one factor that contributes to heterogeneous distribution of biological activity. PMID:19894128

  15. Experiments on Methane Displacement by Carbon Dioxide in Large Coal Specimens

    NASA Astrophysics Data System (ADS)

    Liang, Weiguo; Zhao, Yangsheng; Wu, Di; Dusseault, Maurice B.

    2011-09-01

    Carbon dioxide (CO2) is considered to be the most important greenhouse gas in terms of overall effect. CO2 geological storage in coal beds is of academic and industrial interest because of economic synergies between greenhouse gas sequestration and coal bed methane (CH4) recovery by displacement/adsorption. Previously, most work focused on either theoretical analyses and mathematical simulations or gas adsorption-desorption experiments using coal particles of millimeter size or smaller. Those studies provided basic understanding of CH4 recovery by CO2 displacement in coal fragments, but more relevant and realistic investigations are still rare. To study the processes more realistically, we conducted experimental CH4 displacement by CO2 and CO2 sequestration with intact 100 × 100 × 200 mm coal specimens. The coal specimen permeability was measured first, and results show that the permeability of the specimen is different for CH4 and CO2; the CO2 permeability was found to be at least two orders of magnitude greater than that for CH4. Simultaneously, a negative exponential relationship between the permeability and the applied mean stress on the specimen was found. Under the experimental stress conditions, 17.5-28.0 volumes CO2 can be stored in one volume of coal, and the displacement ratio CO2-CH4 is as much as 7.0-13.9. The process of injection, adsorption and desorption, displacement, and output of gases proceeds smoothly under an applied constant pressure differential, and the CH4 content in the output gas amounted to 20-50% at early stages, persisting to 10-16% during the last stage of the experiments. Production rate and CH4 fraction are governed by complex factors including initial CH4 content, the pore and fissure fabric of the coal, the changes in this fabric as the result of differential adsorption of CO2, the applied stress, and so on. During CO2 injection and CH4 displacement, the coal can swell from effects of gas adsorption and desorption, leading to

  16. An Optical Fiber Lateral Displacement Measurement Method and Experiments Based on Reflective Grating Panel

    PubMed Central

    Li, Yuhe; Guan, Kaisen; Hu, Zhaohui; Chen, Yanxiang

    2016-01-01

    An optical fiber sensing method based on a reflective grating panel is demonstrated for lateral displacement measurement. The reflective panel is a homemade grating with a periodic variation of its refractive index, which is used to modulate the reflected light intensity. The system structure and operation principle are illustrated in detail. The intensity calculation and simulation of the optical path are carried out to theoretically analyze the measurement performance. A distinctive fiber optic grating ruler with a special fiber optic measuring probe and reflective grating panel is set up. Experiments with different grating pitches are conducted, and long-distance measurements are executed to accomplish the functions of counting optical signals, subdivision, and discerning direction. Experimental results show that the proposed measurement method can be used to detect lateral displacement, especially for applications in working environments with high temperatures. PMID:27271624

  17. An Optical Fiber Lateral Displacement Measurement Method and Experiments Based on Reflective Grating Panel.

    PubMed

    Li, Yuhe; Guan, Kaisen; Hu, Zhaohui; Chen, Yanxiang

    2016-01-01

    An optical fiber sensing method based on a reflective grating panel is demonstrated for lateral displacement measurement. The reflective panel is a homemade grating with a periodic variation of its refractive index, which is used to modulate the reflected light intensity. The system structure and operation principle are illustrated in detail. The intensity calculation and simulation of the optical path are carried out to theoretically analyze the measurement performance. A distinctive fiber optic grating ruler with a special fiber optic measuring probe and reflective grating panel is set up. Experiments with different grating pitches are conducted, and long-distance measurements are executed to accomplish the functions of counting optical signals, subdivision, and discerning direction. Experimental results show that the proposed measurement method can be used to detect lateral displacement, especially for applications in working environments with high temperatures. PMID:27271624

  18. Optimizing the experimental design of soil columns in saturated and unsaturated transport experiments.

    PubMed

    Lewis, Jeffrey; Sjöstrom, Jan

    2010-06-25

    Soil column experiments in both the saturated and unsaturated regimes are widely used for applied and theoretical studies in such diverse fields as transport model evaluation, fate and transport of pesticides, explosives, microbes, heavy metals and non aqueous phase liquids, and for evapotranspiration studies. The apparent simplicity of constructing soil columns conceals a number of technical issues which can seriously affect the outcome of an experiment, such as the presence or absence of macropores, artificial preferential flow paths, non-ideal infiltrate injection and unrealistic moisture regimes. This review examines the literature to provide an analysis of the state of the art for constructing both saturated and unsaturated soil columns. Common design challenges are discussed and best practices for potential solutions are presented. This article discusses both basic principles and the practical advantages and disadvantages of various experimental approaches. Both repacked and monolith-type columns are discussed. The information in this review will assist soil scientists, hydrogeologists and environmental professionals in optimizing the construction and operation of soil column experiments in order to achieve their objectives, while avoiding serious design flaws which can compromise the integrity of their results. PMID:20452088

  19. Optimizing the experimental design of soil columns in saturated and unsaturated transport experiments.

    PubMed

    Lewis, Jeffrey; Sjöstrom, Jan

    2010-06-25

    Soil column experiments in both the saturated and unsaturated regimes are widely used for applied and theoretical studies in such diverse fields as transport model evaluation, fate and transport of pesticides, explosives, microbes, heavy metals and non aqueous phase liquids, and for evapotranspiration studies. The apparent simplicity of constructing soil columns conceals a number of technical issues which can seriously affect the outcome of an experiment, such as the presence or absence of macropores, artificial preferential flow paths, non-ideal infiltrate injection and unrealistic moisture regimes. This review examines the literature to provide an analysis of the state of the art for constructing both saturated and unsaturated soil columns. Common design challenges are discussed and best practices for potential solutions are presented. This article discusses both basic principles and the practical advantages and disadvantages of various experimental approaches. Both repacked and monolith-type columns are discussed. The information in this review will assist soil scientists, hydrogeologists and environmental professionals in optimizing the construction and operation of soil column experiments in order to achieve their objectives, while avoiding serious design flaws which can compromise the integrity of their results.

  20. Surgical reconstruction of posterior tibial tendon dysfunction: prospective comparison of flexor digitorum longus substitution combined with lateral column lengthening or medial displacement calcaneal osteotomy.

    PubMed

    Marks, Richard M; Long, Jason T; Ness, Mary Ellen; Khazzam, Michael; Harris, Gerald F

    2009-01-01

    Posterior tibial tendon dysfunction (PTTD) may require surgical intervention when nonoperative measures fail. Different methods of bony reconstruction may supplement tendon substitution. This study compares two types of bony procedures used to reinforce reconstruction of the posterior tibial tendon-the lateral column lengthening (LCL), and the medial displacement calcaneal osteotomy (MDCO). Twenty patients with PTTD were evaluated before and after scheduled reconstruction comprised of either flexor digitorum longus (FDL) substitution combined with MDCO (MDCO group, 14 patients) or FDL substitution with LCL fusion or osteotomy (LCL group, 6 patients). Foot/ankle kinematics and temporal-spatial parameters were analyzed using the Milwaukee Foot Model, and results were compared to a previously evaluated normal population of 25 patients. Post-operatively, both patient groups demonstrated significantly improved stride length, cadence and walking speed, as well as improved hindfoot and forefoot position in the sagittal plane. The LCL group also demonstrated greater heel inversion. All post-operative subjects revealed significant improvement in the talo-MT1 angle in the A/P and lateral planes, calcaneal pitch and medial cuneiform-MT5 height. Surgical reconstruction of PTTD with either the LCL or MDCO shows comparable improvements in gait parameters, with better heel inversion seen with the LCL, but improved 1st ray plantarflexion and varus with the MDCO. Both procedures demonstrated comparable improvements in radiographic measurements. PMID:18603429

  1. Effects of Humidity Swings on Adsorption Columns for Air Revitalization: Modeling and Experiments

    NASA Technical Reports Server (NTRS)

    LeVan, M. Douglas; Finn, John E.

    1997-01-01

    Air purification systems are necessary to provide clean air in the closed environments aboard spacecraft. Trace contaminants are removed using adsorption. One major factor concerning the removal of trace contaminants is relative humidity. Water can reduce adsorption capacity and, due to constant fluctuations, its presence is difficult to incorporate into adsorption column designs. The purpose of the research was to allow for better design techniques in trace contaminant adsorption systems, especially for feeds with water present. Experiments and mathematical modeling research on effects of humidity swings on adsorption columns for air revitalization were carried out.

  2. Aerosol Effects on Radiation and Climate: Column Closure Experiments with Towers, Aircraft, and Satellites

    NASA Technical Reports Server (NTRS)

    Russell, Philip B.

    1994-01-01

    Many theoretical studies have shown that anthropogenic aerosol particles can change the radiation balance in an atmospheric column and might thereby exert a significant effect on the Earth's climate. In particular, recent calculations have shown that sulfate particles from anthropogenic combustion may already exert a cooling influence on the Earth that partially offsets the warming caused by the greenhouse gases from the same combustion. Despite the potential climatic importance of anthropogenic aerosols, simultaneous measurements of anthropogenic aerosol properties and their effect on atmospheric radiation have been very rare. Successful comparisons of measured radiation fields with those calculated from aerosol measurements - now referred to as column closure comparisons - are required to improve the accuracy and credibility of climate predictions. This paper reviews the column closure experiment performed at the Mt. Sutro Tower in San Francisco in 1975, in which elevated radiometers measured the change in Earth-plus-atmosphere albedo caused by an aerosol layer, while a lidar, sunphotometer, nephelometer, and other radiometers measured properties of the responsible aerosol. The time-dependent albedo calculated from the measured aerosol properties agreed with that measured by the tower radiometers. Also presented are designs for future column closure studies using radiometers and aerosol instruments on the ground, aircraft, and satellites. These designs draw upon algorithms and experience developed in the Sutro Tower study, as well as more recent experience with current measurement and analysis capabilities.

  3. Non-linear wave interaction in a magnetoplasma column. I - Theory. II Experiment

    NASA Technical Reports Server (NTRS)

    Larsen, J.-M.; Crawford, F. W.

    1979-01-01

    The paper presents an analysis of non-linear three-wave interaction for propagation along a cylindrical plasma column surrounded either by a metallic boundary, or by an infinite dielectric, and immersed in an infinite, static, axial magnetic field. An averaged Lagrangian method is used and the results are specialized to parametric amplification and mode conversion, assuming an undepleted pump wave. Computations are presented for a magneto-plasma column surrounded by free space, indicating that parametric growth rates of the order of a fraction of a decibel per centimeter should be obtainable for plausible laboratory plasma parameters. In addition, experiments on non-linear mode conversion in a cylindrical magnetoplasma column are described. The results are compared with the theoretical predictions and good qualitative agreement is demonstrated.

  4. A Sea Floor Methane Hydrate Displacement Experiment Using N2 Gas

    NASA Astrophysics Data System (ADS)

    Brewer, P. G.; Peltzer, E. T.; Walz, P. M.; Zhang, X.; Hester, K.

    2009-12-01

    The production of free methane gas from solid methane hydrate accumulations presents a considerable challenge. The presently preferred procedure is pressure reduction whereby the relief of pressure to a condition outside the hydrate phase boundary creates a gas phase. The reaction is endothermic and thus a problematic water ice phase can form if the extraction of gas is too rapid, limiting the applicability of this procedure. Additionally, the removal of the formation water in contact with the hydrate phase is required before meaningful pressure reduction can be attained -- and this can take time. An alternate approach that has been suggested is the injection of liquid CO2 into the formation, thereby displacing the formation water. Formation of a solid CO2 hydrate is thermodynamically favored under these conditions. Competition between CH4 and CO2 for the hydrate host water molecules can occur displacing CH4 from the solid to the gas phase with formation of a solid CO2 hydrate. We have investigated another alternate approach with displacement of the surrounding bulk water phase by N2 gas, resulting in rapid release of CH4 gas and complete loss of the solid hydrate phase. Our experiment was carried out at the Southern Summit of Hydrate Ridge, offshore Oregon, at 780m depth. There we harvested hydrate fragments from surficial sediments using the robotic arm of the ROV Doc Ricketts. Specimens of the hydrate were collected about 1m above the sediment surface in an inverted funnel with a mesh covered neck as they floated upwards. The accumulated hydrate was transferred to an inverted glass cylinder, and N2 gas was carefully injected into this container. Displacement of the water phase occurred and when the floating hydrate material approached the lower rim the gas injection was stopped and the cylinder placed upon a flat metal plate effectively sealing the system. We returned to this site after 7 days to measure progress, and observed complete loss of the hydrate phase

  5. Single-experiment displacement assay for quantifying high-affinity binding by isothermal titration calorimetry.

    PubMed

    Krainer, Georg; Keller, Sandro

    2015-04-01

    Isothermal titration calorimetry (ITC) is the gold standard for dissecting the thermodynamics of a biomolecular binding process within a single experiment. However, reliable determination of the dissociation constant (KD) from a single titration is typically limited to the range 100 μM>KD>1 nM. Interactions characterized by a lower KD can be assessed indirectly by so-called competition or displacement assays, provided that a suitable competitive ligand is available whose KD falls within the directly accessible window. However, this protocol is limited by the fact that it necessitates at least two titrations to characterize one high-affinity inhibitor, resulting in considerable consumption of both sample material and time. Here, we introduce a fast and efficient ITC displacement assay that allows for the simultaneous characterization of both a high-affinity ligand and a moderate-affinity ligand competing for the same binding site on a receptor within a single experiment. The protocol is based on a titration of the high-affinity ligand into a solution containing the moderate-affinity ligand bound to the receptor present in excess. The resulting biphasic binding isotherm enables accurate and precise determination of KD values and binding enthalpies (ΔH) of both ligands. We discuss the theoretical background underlying the approach, demonstrate its practical application to metal ion chelation, explore its potential and limitations with the aid of simulations and statistical analyses, and elaborate on potential applications to protein-inhibitor interactions.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

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

    NASA Astrophysics Data System (ADS)

    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

  8. Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments

    USGS Publications Warehouse

    Yin, Jun; Haggerty, Roy; Stoliker, Deborah L.; Kent, Douglas B.; Istok, Jonathan D.; Greskowiak, Janek; Zachara, John M.

    2011-01-01

    In the 300 Area of a U(VI)-contaminated aquifer at Hanford, Washington, USA, inorganic carbon and major cations, which have large impacts on U(VI) transport, change on an hourly and seasonal basis near the Columbia River. Batch and column experiments were conducted to investigate the factors controlling U(VI) adsorption/desorption by changing chemical conditions over time. Low alkalinity and low Ca concentrations (Columbia River water) enhanced adsorption and reduced aqueous concentrations. Conversely, high alkalinity and high Ca concentrations (Hanford groundwater) reduced adsorption and increased aqueous concentrations of U(VI). An equilibrium surface complexation model calibrated using laboratory batch experiments accounted for the decrease in U(VI) adsorption observed with increasing (bi)carbonate concentrations and other aqueous chemical conditions. In the column experiment, alternating pulses of river and groundwater caused swings in aqueous U(VI) concentration. A multispecies multirate surface complexation reactive transport model simulated most of the major U(VI) changes in two column experiments. The modeling results also indicated that U(VI) transport in the studied sediment could be simulated by using a single kinetic rate without loss of accuracy in the simulations. Moreover, the capability of the model to predict U(VI) transport in Hanford groundwater under transient chemical conditions depends significantly on the knowledge of real-time change of local groundwater chemistry.

  9. Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments

    USGS Publications Warehouse

    Yin, J.; Haggerty, R.; Stoliker, D.L.; Kent, D.B.; Istok, J.D.; Greskowiak, J.; Zachara, J.M.

    2011-01-01

    In the 300 Area of a U(VI)-contaminated aquifer at Hanford, Washington, USA, inorganic carbon and major cations, which have large impacts on U(VI) transport, change on an hourly and seasonal basis near the Columbia River. Batch and column experiments were conducted to investigate the factors controlling U(VI) adsorption/desorption by changing chemical conditions over time. Low alkalinity and low Ca concentrations (Columbia River water) enhanced adsorption and reduced aqueous concentrations. Conversely, high alkalinity and high Ca concentrations (Hanford groundwater) reduced adsorption and increased aqueous concentrations of U(VI). An equilibrium surface complexation model calibrated using laboratory batch experiments accounted for the decrease in U(VI) adsorption observed with increasing (bi)carbonate concentrations and other aqueous chemical conditions. In the column experiment, alternating pulses of river and groundwater caused swings in aqueous U(VI) concentration. A multispecies multirate surface complexation reactive transport model simulated most of the major U(VI) changes in two column experiments. The modeling results also indicated that U(VI) transport in the studied sediment could be simulated by using a single kinetic rate without loss of accuracy in the simulations. Moreover, the capability of the model to predict U(VI) transport in Hanford groundwater under transient chemical conditions depends significantly on the knowledge of real-time change of local groundwater chemistry. Copyright 2011 by the American Geophysical Union.

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

    NASA Astrophysics Data System (ADS)

    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 <0.2 mg l -1 to approximately 4 mg l -1. Degradation rates of atrazine in oxygenated groundwater were relatively high with a zero-order rate of 240-380 μg l -1 or a first-order half-life of 0.35 days. Amendment with an additional carbon source showed no significant improvement in 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.

  11. Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments

    SciTech Connect

    Yin, Jun; Haggerty, Roy; Stoliker, Deborah L.; Kent, Douglas B.; Istok, Jonathan D.; Greskowiak, Janek; Zachara, John M.

    2011-04-05

    In the 300 Area of a U(VI)-contaminated aquifer at Hanford, Washington, USA, inorganic carbon and major cations, which have large impacts on U(VI) transport, change on an hourly and seasonal basis near the Columbia River. Batch and column experiments were conducted to investigate the factors controlling U(VI) adsorption/desorption by changing chemical conditions over time. Low alkalinity and low Ca concentrations (Columbia River water) enhanced adsorption and reduced aqueous concentrations. Conversely, high alkalinity and high Ca concentrations (Hanford groundwater) reduced adsorption and increased aqueous concentrations of U(VI). An equilibrium surface complexation model calibrated using laboratory batch experiments accounted for the decrease in U(VI) adsorption observed with increasing (bi)carbonate concentrations and other aqueous chemical conditions. In the column experiment, alternating pulses of river and groundwater caused swings in aqueous U(VI) concentration. A multispecies multirate surface complexation reactive transport model simulated most of the major U(VI) changes in two column experiments. The modeling results also indicated that U(VI) transport in the studied sediment could be simulated by using a single kinetic rate without loss of accuracy in the simulations. Moreover, the capability of the model to predict U(VI) transport in Hanford groundwater under transient chemical conditions depends significantly on the knowledge of real-time change of local groundwater chemistry.

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

    PubMed

    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 <0.2 mg l(-1) to approximately 4 mg l(-1). Degradation rates of atrazine in oxygenated groundwater were relatively high with a zero-order rate of 240-380 microg l(-1) or a first-order half-life of 0.35 days. Amendment with an additional carbon source showed no significant improvement in 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.

  13. Preliminary results of column experiments simulating nutrients transport in artificial recharge by treated wastewater

    NASA Astrophysics Data System (ADS)

    Leal, María; Meffe, Raffaella; Lillo, Javier

    2013-04-01

    Nutrients (phosphates, nitrates, nitrites and ammonium) are very often present in treated wastewater as consequence of the inefficient removal capability during wastewater treatments. Such compounds represent an environmental concern since they are responsible for contamination and/or eutrophication problems when reaching the water bodies (groundwater, river, streams…). Therefore, when wastewater reclamation activities such as artificial recharge are planned, special attention should be paid to these compounds to avoid groundwater deterioration. In this context, we proposed the installation of a Horizontal Permeable Reactive Barrier (H-PRB) made of different reactive materials, among them zeolite and palygorskite, to remove nutrients or at least to decrease their concentrations. The overall aim of this research is to evaluate if the application of a H-PRB could represent a feasible solution for the attenuation of nutrients when unconventional water resources (i.e. treated wastewater) are used for recharge activities. Specifically, this study is intended to identify the transport processes affecting nitrates, nitrites, ammonium and phosphates when treated wastewater is infiltrated through the reactive materials of the H-PRB. Column experiments are generally suitable to examine the interactions between reactive materials and treated wastewater that affect the transport behavior of nutrients. For example, processes such as adsorption can be identified and quantified. Thus, laboratory column experiments were carried out using zeolite or palygorskite as column infilling material and synthetic treated wastewater as column influent. The experiments are closely connected to an experimental field study in Carrión de los Céspedes (Seville-Spain) where a pilot H-PRB is currently under evaluation. The columns were operated under saturated conditions applying a constant flow rate of 1.2 mL/min equivalent to the infiltration rate estimated through infiltration experiments at

  14. MISCIBLE FLUID DISPLACEMENT STABILITY IN UNCONFINED POROUS MEDIA: TWO-DIMENSIONAL FLOW EXPERIMENTS AND SIMULATIONS

    EPA Science Inventory

    In situ flushing groundwater remediation technologies, such as cosolvent flushing, rely on the stability of the interface between the resident and displacing fluids for efficient removal of contaminants. Contrasts in density and viscosity between the resident and displacing flui...

  15. Tomographic Analysis of Reactive Flow Induced Pore Structure Changes in Column Experiments

    SciTech Connect

    Cai, Rong; Lindquist, W.Brent; Um, Wooyong; Jones, Keith W.

    2009-09-23

    We utilize synchrotron X-ray computed microtomography to capture and quantify snapshots in time of dissolution and secondary precipitation in the microstructure of Hanford sediments exposed to simulated caustic waste in flow-column experiments. The experiment is complicated somewhat as logis- tics dictated that the column spent significant amounts of time in a sealed state (acting as a batch reactor). Changes accompanying a net reduction in porosity of 4% were quantified including: 1) a 25% net decrease in pores resulting from a 38% loss in the number of pores less than < 10-4 MM3 in volume and a 13% increase in the number of pores of larger size; and 2) a 38% decrease in the number of throats. The loss of throats resulted in de- creased coordination number for pores of all sizes and significant reduction in the number of pore pathways.

  16. A clay permeable reactive barrier to remove Cs-137 from groundwater: Column experiments.

    PubMed

    De Pourcq, K; Ayora, C; García-Gutiérrez, M; Missana, T; Carrera, J

    2015-11-01

    Clay minerals are reputed sorbents for Cs-137 and can be used as a low-permeability material to prevent groundwater flow. Therefore, clay barriers are employed to seal Cs-137 polluted areas and nuclear waste repositories. This work is motivated by cases where groundwater flow cannot be impeded. A permeable and reactive barrier to retain Cs-137 was tested. The trapping mechanism is based on the sorption of cesium on illite-containing clay. The permeability of the reactive material is provided by mixing clay on a matrix of wood shavings. Column tests combined with reactive transport modeling were performed to check both reactivity and permeability. Hydraulic conductivity of the mixture (10(-4) m/s) was sufficient to ensure an adequate hydraulic performance of an eventual barrier excavated in most aquifers. A number of column experiments confirmed Cs retention under different flow rates and inflow solutions. A 1D reactive transport model based on a cation-exchange mechanism was built. It was calibrated with batch experiments for high concentrations of NH4+ and K+ (the main competitors of Cs in the exchange positions). The model predicted satisfactorily the results of the column experiments. Once validated, it was used to investigate the performance and duration of a 2 m thick barrier under different scenarios (flow, clay content, Cs-137 and K concentration).

  17. A clay permeable reactive barrier to remove Cs-137 from groundwater: Column experiments.

    PubMed

    De Pourcq, K; Ayora, C; García-Gutiérrez, M; Missana, T; Carrera, J

    2015-11-01

    Clay minerals are reputed sorbents for Cs-137 and can be used as a low-permeability material to prevent groundwater flow. Therefore, clay barriers are employed to seal Cs-137 polluted areas and nuclear waste repositories. This work is motivated by cases where groundwater flow cannot be impeded. A permeable and reactive barrier to retain Cs-137 was tested. The trapping mechanism is based on the sorption of cesium on illite-containing clay. The permeability of the reactive material is provided by mixing clay on a matrix of wood shavings. Column tests combined with reactive transport modeling were performed to check both reactivity and permeability. Hydraulic conductivity of the mixture (10(-4) m/s) was sufficient to ensure an adequate hydraulic performance of an eventual barrier excavated in most aquifers. A number of column experiments confirmed Cs retention under different flow rates and inflow solutions. A 1D reactive transport model based on a cation-exchange mechanism was built. It was calibrated with batch experiments for high concentrations of NH4+ and K+ (the main competitors of Cs in the exchange positions). The model predicted satisfactorily the results of the column experiments. Once validated, it was used to investigate the performance and duration of a 2 m thick barrier under different scenarios (flow, clay content, Cs-137 and K concentration). PMID:26197347

  18. Heat storage in the Hettangian aquifer in Berlin - results from a column experiment

    NASA Astrophysics Data System (ADS)

    Milkus, Chri(Sch)augott

    2015-04-01

    Aquifer Thermal Energy Storage (ATES) is a sustainable alternative for storage and seasonal availability of thermal energy. However, its impact on the subsurface flow regime is not well known. In Berlin (Germany), the Jurassic (Hettangian) sandstone aquifer with highly mineralized groundwater (TDS 27 g/L) is currently used for heat storage. The aim of this study was to examine the hydrogeochemical changes that are caused by the induced temperature shift and its effects on the hydraulic permeability of the aquifer. Column experiments were conducted, in which stainless steel columns were filled with sediment from the aquifer and flushed with native groundwater for several weeks. The initial temperature of the experiment was 20°C, comparable to the in-situ conditions within the aquifer. After reaching equilibrium between sediment and water, the temperature was increased to simulate heating of the aquifer. During the experiment, physical and chemical parameters (pH, ORP, dissolved oxygen and dissolved carbon dioxide) were measured at the outflow of the column and the effluent water was sampled. Using a Scanning Electron Microscope, the deposition of precipitated minerals and biofilm on sediment grains was analyzed. Changes in hydraulic properties of the sediment were studied by the use of tracer tests with Uranin.

  19. Walker Branch Throughfall Displacement Experiment Data Report: Site Characterization, System Performance, Weather, Species Composition, and Growth

    SciTech Connect

    Hanson, P.J.

    2001-09-04

    This numeric data package provides data sets, and accompanying documentation, on site characterization, system performance, weather, species composition, and growth for the Throughfall Displacement Experiment, which was established in the Walker Branch Watershed of East Tennessee to provide data on the responses of forests to altered precipitation regimes. The specific data sets include soil water content and potential, coarse fraction of the soil profile, litter layer temperature, soil temperature, monthly weather, daily weather, hourly weather, species composition of trees and saplings, mature tree and sapling annual growth, and relative leaf area index. Fortran and SAS{trademark} access codes are provided to read the ASCII data files. The data files and this documentation are available without charge on a variety of media and via the Internet from the Carbon Dioxide Information Analysis Center (CDIAC).

  20. Redox-sensitivity and mobility of selected pharmaceutical compounds in a laboratory column experiment

    NASA Astrophysics Data System (ADS)

    Banzhaf, S.; Nödler, K.; Licha, T.; Krein, A.; Scheytt, T.

    2012-04-01

    Laboratory column experiments are suitable to investigate the sediment water interaction and to study the transport behaviour of solutes. Processes like retardation and degradation can be identified and quantified. The conducted experiment, which is closely connected to a field study in Luxembourg, investigated the transport behaviour of selected pharmaceutical compounds and their redox-dependent metabolism under water saturated conditions. Fine-grained natural sediment with a low hydraulic conductivity from a study site in Luxembourg was filled into the column. The water for the experiment was taken from a small stream at the same fieldsite. It was spiked with four pharmaceutical compounds (carbamazepine, diclofenac, ibuprofen, sulfamethoxazole) with concentrations between 170 and 300 ng/L for the different substances. The chosen pharmaceuticals were also detected in groundwater and surface water samples at the study site and used to qualify exchange/mixing of surface water and groundwater (BANZHAF et al., 2011). As some of the substances are known to exhibit redox-sensitive degradation, the redox-conditions were systematically varied throughout the experiment. This was realised by adding nitrate at the inflow of the column. During the experiment, which lasted for 2.5 months, four different nitrate concentrations (20-130 mg/L) were applied, beginning with the highest concentration. During the experiment water from the reservoir tank was sampled daily in order to detect a potential degradation of the pharmaceutical compounds before they enter the column. The effluent water was sampled every three hours to guarantee a maximum resolution for the analysis of the pharmaceuticals where necessary. In addition, major ions were analysed in the influent and effluent samples. Throughout the experiment physicochemical parameters (oxidation reduction potential (ORP), dissolved oxygen, electrical conductivity, and pH-value) were measured and logged at the outflow of the column

  1. Column experiment to study isotope fractionation of volatile organic contaminants in porous media under unsaturated conditions

    NASA Astrophysics Data System (ADS)

    Jeannottat, Simon; Hunkeler, Daniel; Breider, Florian

    2010-05-01

    Pollution by organic contaminants such as petroleum hydrocarbons and chlorinated solvents is common in industrialized countries. The use of stable isotope analysis is increasingly recognized as a powerful technique for investigating the behaviour of organic or inorganic contaminants. Recently, compound-specific isotope analysis (CSIA) has proven to be an effective tool to confirm and quantify in-situ biodegradation by indigenous microbial populations in groundwater.In contrast, only few studies have investigated the use of CSIA in the unsaturated zone. In the unsaturated zone, the main potential applications of CSIA include the assessment of biodegradation and the fingerprinting of different sources of petroleum hydrocarbon or chlorinated solvents vapours. However, it has to be taken into account that isotope ratios in the unsaturated zone can vary due to diffusion and volatilization in addition to biodegradation. For application of isotope methods in the unsaturated zone, it is crucial to quantify isotopic fractionation resulting from physico-chemical and transport processes. The study is focused on laboratory experiments that investigate the effect of vaporization and diffusion on isotope ratios. The effect of diffusion is carried out using a column experiment setup that can be considered to represent VOC transport from a floating NAPL towards the atmosphere. Furthermore, additional column and batch experiments will be conducted to better understand the effect of biodegradation. Volatilization is studied with an other experimental setup. In addition, a mathematical framework was developed to simulate the isotope evolution in the column study. Since the initial experiments aimed at investigating the effect of vaporization and diffusion only, the column is filled with dry quartz sand in order to avoid perturbations of concentration profiles by humidity or adsorption on organic matter. An activated sand will later be used for the biodegradation experiments. A

  2. Numerical simulations of the flow with the prescribed displacement of the airfoil and comparison with experiment

    NASA Astrophysics Data System (ADS)

    Řidký, V.; Šidlof, P.; Vlček, V.

    2013-04-01

    The work is devoted to comparing measured data with the results of numerical simulations. As mathematical model was used mathematical model whitout turbulence for incompressible flow In the experiment was observed the behavior of designed NACA0015 airfoil in airflow. For the numerical solution was used OpenFOAM computational package, this is open-source software based on finite volume method. In the numerical solution is prescribed displacement of the airfoil, which corresponds to the experiment. The velocity at a point close to the airfoil surface is compared with the experimental data obtained from interferographic measurements of the velocity field. Numerical solution is computed on a 3D mesh composed of about 1 million ortogonal hexahedron elements. The time step is limited by the Courant number. Parallel computations are run on supercomputers of the CIV at Technical University in Prague (HAL and FOX) and on a computer cluster of the Faculty of Mechatronics of Liberec (HYDRA). Run time is fixed at five periods, the results from the fifth periods and average value for all periods are then be compared with experiment.

  3. Particle image velocimetry for the Surface Tension Driven Convection Experiment using a particle displacement tracking technique

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.; Pline, Alexander D.

    1991-01-01

    The Surface Tension Driven Convection Experiment (STDCE) is a Space Transportation System flight experiment to study both transient and steady thermocapillary fluid flows aboard the USML-1 Spacelab mission planned for 1992. One of the components of data collected during the experiment is a video record of the flow field. This qualitative data is then quantified using an all electronic, two-dimensional particle image velocimetry technique called particle displacement tracking (PDT) which uses a simple space domain particle tracking algorithm. The PDT system is successful in producing velocity vector fields from the raw video data. Application of the PDT technique to a sample data set yielded 1606 vectors in 30 seconds of processing time. A bottom viewing optical arrangement is used to image the illuminated plane, which causes keystone distortion in the final recorded image. A coordinate transformation was incorporated into the system software to correct this viewing angle distortion. PDT processing produced 1.8 percent false identifications, due to random particle locations. A highly successful routine for removing the false identifications was also incorporated, reducing the number of false identifications to 0.2 percent.

  4. Particle image velocimetry for the surface tension driven convection experiment using a particle displacement tracking technique

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.; Pline, Alexander D.

    1991-01-01

    The Surface Tension Driven Convection Experiment (STDCE) is a Space Transportation System flight experiment to study both transient and steady thermocapillary fluid flows aboard the USML-1 Spacelab mission planned for 1992. One of the components of data collected during the experiment is a video record of the flow field. This qualitative data is then quantified using an all electronic, two-dimensional particle image velocimetry technique called particle displacement tracking (PDT) which uses a simple space domain particle tracking algorithm. The PDT system is successful in producing velocity vector fields from the raw video data. Application of the PDT technique to a sample data set yielded 1606 vectors in 30 seconds of processing time. A bottom viewing optical arrangement is used to image the illuminated plane, which causes keystone distortion in the final recorded image. A coordinate transformation was incorporated into the system software to correct this viewing angle distortion. PDT processing produced 1.8 percent false identifications, due to random particle locations. A highly successful routine for removing the false identifications was also incorporated, reducing the number of false identifications to 0.2 percent.

  5. Correct Characterization of Passive Tracer Dispersion in Porous Columns: Experiments vs. Theory

    NASA Astrophysics Data System (ADS)

    Cortis, A.; Scher, H.; Berkowitz, B.

    2004-12-01

    Breakthrough curves (BTC) of a passive tracer in macroscopically ``homogeneous'' granular materials (well-sorted, unconsolidated sands or glass beads) were measured in a series of column experiments. % In parallel, classical experiments on dispersion of a passive tracer in fully and partially saturated porous columns were re-examined. % All of these BTCs exhibit anomalous (non-Fickian) features: early and late arrival times are observed to differ systematically from theoretical predictions based on solution of the advective-dispersion equation (ADE) for uniform porous media. % We propose that even in these small-scale, ``homogeneous'' porous medium columns, subtle and residual pore-scale disorder effects can account for these observations. % In a Continuous Time Random Walk (CTRW) framework, we determined an ensemble-averaged distribution of particle transfer rates (based on a Master Equation for the local flux-averaged concentration) which accounts for these effects. % Solutions of the resulting CTRW transport equations yield BTCs that are in excellent agreement with the entire series of observations. % The CTRW formulation also specifies the dependence of the effective macroscopic parameters on measurable quantities. % The theoretical predictions are in excellent agreement with the observations. % It is critical to understand that as a consequence of our results, the ADE should not be taken as the starting point of any upscaling technique. % Our analyses demonstrate that existing measurements and interpretations of tracer dispersion experiments in laboratory experiments should be carefully re-considered in the framework of these recent advances in conceptual understanding and quantification. % These results have also important implications for modeling the transport of contaminants in large-scale, highly-heterogeneous, hydrogeological systems.

  6. Identification of transport processes in column experiments using a frequency domain approach

    NASA Astrophysics Data System (ADS)

    Shuai, Xiufu; Yost, Russell S.

    2007-10-01

    When a solute transport process is viewed as a dynamic system with input and output, a system identification technique can be used to study it from input-output data. According to the design of excitation signals in the system identification approach, the commonly used rectangular pulse as input signal for column experiments is not optimum because it does not simultaneously meet the requirements for exciting the studied transport process, i.e., possessing frequency components with high enough amplitude and wide enough passband. In this article, stepped sine signals were proposed to replace the rectangular pulse because their amplitude and passband can be independently chosen. The stepped sine signals of concentration were generated by a High Performance Liquid Chromatography (HPLC) and used as the input for the column experiments to identify parameters of the convection-dispersion equation (CDE) and mobile-immobile model (MIM). In order to test the effect of noise on the identification of transport process, numerical experiments were carried out to identify the CDE under white noise when the input was designed as stepped sine functions and rectangular pulse. The results of the numerical experiments showed that the input signal of a sine function was more robust and accurate in process identification than that of a rectangular pulse.

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

    EPA Science Inventory

    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 ...

  8. Constructing Physical Heterogeneity in the Lab: Varying Permeability Distributions in Flow-through Column Experiments

    NASA Astrophysics Data System (ADS)

    Lewis, A. J.; Druhan, J. L.; Maher, K.

    2013-12-01

    the columns, the coarse grain sand has a permeability of approximately 720 mD and the fine grain approximately 450 mD. Flow-through tracer experiments are run in each of the columns using a pulse injection of 1000 ppm chloride to test a variety of flow rates and consequent mean fluid residence times. The tracer is injected inline within a continuous background flow of 2 ppm chloride in 18.2 MΩ-cm deionized water and effluent solute concentrations are measured as a function of time. Our results indicate that, for an inert tracer, flow through heterogeneous permeability domains will result in a delay in the breakthrough of the solute in comparison to a homogenous system as a function of the flow rate. Furthermore, we suggest that the surface area of contact between distinct permeability zones exerts a primary influence on solute transport through heterogeneous porous media. These results are tested for a range of experimental conditions in the CrunchFlow reactive transport code, allowing characterization of the effects of the physical heterogeneity on the fluid residence time of reactive species.

  9. Psychosocial effects of war experiences among displaced children in southern Darfur.

    PubMed

    Morgos, Dorothy; Worden, J William; Gupta, Leila

    This study focused on assessing the psychosocial effects of the long standing, high intensity, and guerrilla-style of warfare among displaced children in Southern Darfur. The goal was to better understand the etiology, prognosis, and treatment implications for traumatic reactions, depression, and grief symptoms in this population. Three hundred thirty-one children aged 6-17 from three IDP Camps were selected using a quota sampling approach and were administered a Demographic Questionnaire, Child Post Traumatic Stress Reaction Index, Child Depression Inventory, and the Expanded Grief Inventory. Forty-three percent were girls and 57% were boys. The mean age of the children was 12 years. Results found that children were exposed to a very large number of war experiences with no significant differences between genders for types of exposure, including rape, but with older children (13-17 years) facing a larger number of exposures than younger children (6-12 years). Out of the 16 possible war experiences, the mean number was 8.94 (SD = 3.27). Seventy-five percent of the children met the DSM-IV criteria for PTSD, and 38% exhibited clinical symptoms of depression. The percentage of children endorsing significant levels of grief symptoms was 20%. Increased exposure to war experiences led to higher levels of: (1) traumatic reactions; (2) depression; and (3) grief symptoms. Of the 16 war experiences, abduction, hiding to protect oneself, being raped, and being forced to kill or hurt family members were most predictive of traumatic reactions. Being raped, seeing others raped, the death of a parent/s, being forced to fight, and having to hide to protect oneself were the strongest predictors of depressive symptoms. War experiences such as abduction, death of one's parent/s, being forced to fight, and having to hide to protect oneself were the most associated with the child's experience of grief. In addition to Total Grief, Traumatic Grief, Existential Grief, and Continuing Bonds

  10. Psychosocial effects of war experiences among displaced children in southern Darfur.

    PubMed

    Morgos, Dorothy; Worden, J William; Gupta, Leila

    This study focused on assessing the psychosocial effects of the long standing, high intensity, and guerrilla-style of warfare among displaced children in Southern Darfur. The goal was to better understand the etiology, prognosis, and treatment implications for traumatic reactions, depression, and grief symptoms in this population. Three hundred thirty-one children aged 6-17 from three IDP Camps were selected using a quota sampling approach and were administered a Demographic Questionnaire, Child Post Traumatic Stress Reaction Index, Child Depression Inventory, and the Expanded Grief Inventory. Forty-three percent were girls and 57% were boys. The mean age of the children was 12 years. Results found that children were exposed to a very large number of war experiences with no significant differences between genders for types of exposure, including rape, but with older children (13-17 years) facing a larger number of exposures than younger children (6-12 years). Out of the 16 possible war experiences, the mean number was 8.94 (SD = 3.27). Seventy-five percent of the children met the DSM-IV criteria for PTSD, and 38% exhibited clinical symptoms of depression. The percentage of children endorsing significant levels of grief symptoms was 20%. Increased exposure to war experiences led to higher levels of: (1) traumatic reactions; (2) depression; and (3) grief symptoms. Of the 16 war experiences, abduction, hiding to protect oneself, being raped, and being forced to kill or hurt family members were most predictive of traumatic reactions. Being raped, seeing others raped, the death of a parent/s, being forced to fight, and having to hide to protect oneself were the strongest predictors of depressive symptoms. War experiences such as abduction, death of one's parent/s, being forced to fight, and having to hide to protect oneself were the most associated with the child's experience of grief. In addition to Total Grief, Traumatic Grief, Existential Grief, and Continuing Bonds

  11. Vibration control experiment design for the 15-m hoop/column antenna

    NASA Technical Reports Server (NTRS)

    Ham, F. M.; Hyland, D. C.

    1985-01-01

    A test program is designed for a ground-based vibration control experiment utilizing as the test article the 15-M Hoop/Column Antenna. Overall objectives of the designed ground-based test program include: (1) the validation of large space structure (LSS) control systemm techniques; (2) the validation of LSS parameter identification techniques: (3) the evaluation of actuator of actuator and sensor placement methodology; and (3) the validation of LSS computer models. Critical concerns in LSS Controls and Dynamics are: low frequency vibrational modes, close modal spacing, parameter uncertainties, controller software limitations, nonlinearities and coupling of modes through damping. Analytical results are presented which include compensator designs for varying compensator order.

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

    PubMed

    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.

  13. Cyclic hysteretic flow in porous medium column: model, experiment, and simulations

    NASA Astrophysics Data System (ADS)

    Stauffer, F.; Kinzelbach, W.

    2001-01-01

    A periodic vertical movement of the groundwater table results in a subsequent cyclic response of the water content and pressure profiles in the vadose zone. The sequence of periodic wetting and drying processes can be affected by hysteresis effects in this zone. A one-dimensional saturated/unsaturated flow model based on Richards' equation and the Mualem (Soil Sci. 137 (1984) 283) hysteresis model is formulated which can take into account multi-cycle hysteresis effects in the relation between capillary pressure and water content. The numerical integration of the unsaturated flow equation is based on a Galerkin-type finite element method. The flow domain is discretised by finite elements with linear shape functions. Simulations start with static water content and pressure profiles, which correspond to either a boundary drying or wetting retention curve. To facilitate the numerical solution of the hysteretic case an implicit non-iterative procedure was chosen for the solution of the nonlinear differential equation. Laboratory experiments were performed with a vertical sand column by imposing a high frequency periodic pressure head at the lower end of the column. The total water volume in the column, and the periodic water content profile averaged over time were measured. The boundary drying and wetting curves of the relation between water content and capillary pressure were determined by independent experiments. The simulations of the experimental conditions show a clear effect of the hysteresis phenomenon on the water content profile. The simulations with hysteresis agree well with the measurements. Computed dimensionless water content profiles are presented for different oscillation frequencies with and without consideration of hysteresis.

  14. Beyond the Factory Floor: The Experiences of Displaced Manufacturing Workers as They Retrain in Community College Settings

    ERIC Educational Resources Information Center

    Entz, Mary J.

    2010-01-01

    This study describes and examines the experiences of displaced manufacturing workers as they lose jobs and retrain in community college settings. The analysis included perceptions of community college services and programming designed to help the workers transition into retraining programs, along with those factors that they identified as…

  15. Identification of descriptive parameters of gradated soils using column experiments and analysis of CT data

    NASA Astrophysics Data System (ADS)

    Binner, Richard; Homberg, Ulrike; Prohaska, Steffen; Kalbe, Ute; Berger, Wolfgang; Witt, Karl Josef

    2010-05-01

    In this contribution, we present a method that combines experimental and micro-tomographic information to derive parameters of the pore structure of gradated soils. High-resolution CT data of samples of gradated soils are acquired. Parameters such as the pore positions and the pore sizes, the pore paths, and the pore constrictions are computed by applying methods of image analysis. Further, specific parameters of the pore and soil structure are determined using column and compacting experiments based on model soils. The grain size and effluent quantity of potentially mobile particles are identified, as well as the characteristics of the supporting skeleton of the model. The results of a comparison of both methods suggest that column experiments in combination with automatic image processing methods can provide suitable geometric parameters of real grain and pore structure for analyzing suffosive erosion phenomena. This visualization allows a better understanding of the various physical processes within the pore structure. But for a qualitative approach these parameters can be incorporated into pore-network models to verify existing transport models. This research is a part of a comprehensive research project on suffosion of soils.

  16. Mental health of displaced and returnee populations: Insight from the Sri Lankan post-conflict experience.

    PubMed

    Siriwardhana, Chesmal

    2015-01-01

    The month of May 2015 marked the sixth year since the end of conflict in Sri Lanka. The cause of death, destruction and displacement, three decades of conflict has had a major impact on health, especially on mental health of those affected by forced displacement. Post-conflict regions of Sri Lanka has seen improvements in many areas, including resettlement of displaced populations and rebuilding of health-related infrastructure. However, substantial gaps exist around the management of health needs among returnee populations, especially in the area of psychosocial health. Long-term mental health and resilience trajectories of those affected by prolonged displacement and experiencing return migration during post-conflict periods remain important, yet critically understudied areas.

  17. Fiber-optic displacement sensors on the Hunters Trophy UGT impulse gauge experiments

    SciTech Connect

    Green, R.E.L.; Poutiatine, A.I.

    1995-03-01

    As part of a program to develop gauges for measurement of various mechanical properties in hostile environments, the authors fielded purely optical displacement sensors at the ends of long fiber-optic cables as supplements to the regular displacement sensors of four impulse gauges fielded as part of a materials study on the Hunters Trophy underground effects test at the Nevada Test Site. These fiber-optic sensor systems and their performance on the Hunters Trophy test are described in this report.

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    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

  20. Investigating Attachment Behaviors of Cryptosporidium Parvum Oocysts Using Collision Efficiency in Laboratory Column Experiments

    NASA Astrophysics Data System (ADS)

    Park, Y.; Hou, L.; Atwill, R.; Packman, A. I.; Harter, T.

    2009-12-01

    Cryptosporidium is one of the most common enteric parasites of humans and domestic animals, and a number of outbreaks of Cryprosporidiosis, a diarrheal disease caused by Cryptosporidium have been reported worldwide. Natural porous media has been demonstrated to be an effective filter for removing Cryptosporidium parvum from contaminated water and the amount of Cryptosporidium filtered is known to be highly dependent on physical and chemical conditions of the porous media and the water. Cryptosporidium deposition in saturated porous media involves two main steps: approach and attachment. In contrast to the approach mechanisms, attachment processes have not been systematically described to predict a priori because theories that represent attachment behavior (colloid stability) such as DLVO are insufficient to explain experimental data. For this reason, attachment efficiency is calculated based on empirical data, typically experimental breakthrough curves in laboratory columns or field experiments. In this study, collision (attachment) efficiencies (α) of C. parvum oocyst were calculated to test the effect of chemical property changes on the association of oocysts with sand grains. The breakthrough curve data obtained from twelve column experiments and three models were employed to calculate single collector efficiency (η) and α. The first ten experiments were conducted by changing ionic strength and pH, and mixing with natural sediments under the same physical properties (same η). Our experiment results show that iron coating or clay/suspended solids mixture drastically enhanced oocyst deposition. The experiments also showed that increase in ionic strength and decrease in pH enhanced the attachment efficiency. However, the experiment with 100mM NaCl resulted in low attachment efficiency and the experiment with pH 8.5 showed similar attachment efficiency to the one at pH 7. Based on the results from two additional experiments with different flow velocities, it

  1. Insight into the dynamics of granular column collapse using Discrete Element Methods and laboratory experiments

    NASA Astrophysics Data System (ADS)

    Martin, Hugo; Mangeney, Anne; Farin, Maxime; Richard, Patrick

    2016-04-01

    The mechanical behavior of granular flows is still an open issue. In particular, quantitative agreement between the detailed dynamics of the flow and laboratory experiments is necessary to better constrain the performance and limits of the models. We propose here to compare quantitatively the flow profiles and the force during granular column collapse simulated using Discrete Element Models and laboratory experiments. These small scale experiments are performed with dry granular material released initially from a cylinder on a sloping plane. The flow profiles and the acoustic signal generated by the granular impacts and stresses on the plane are recorded systematically [Farin et al., 2015]. These experiments are simulated using the Discrete Element Method Modys [Richard et al., 2000]. We show that the effect of the removing gate should be taken into account in the model in order to quantatively reproduce the flow dynamics. Furthermore we compare the simulated and observed acoustic signals that are generated by the fluctuating stresses exerted by the grains on the substrate in different frequency bands. [1] P. Richard et Luc Oger. 2000 Etude de la géométrie de milieux granulaires modèles tridimensionnels par simulation numérique. [2] Farin, M., Mangeney, A., Toussaint, R., De Rosny, J., Shapiro, N., Dewez, T., Hibert, C., Mathon, C., Sedan, O., Berger. 2015, Characterization of rockfalls from seismic signal: insights from laboratory experiments

  2. Laboratory column experiments for radionuclide adsorption studies of the Culebra dolomite member of the Rustler Formation

    SciTech Connect

    Lucero, D.A.; Heath, C.E.; Brown, G.O.

    1998-04-01

    Radionuclide transport experiments were carried out using intact cores obtained from the Culebra member of the Rustler Formation inside the Waste Isolation Pilot Plant, Air Intake Shaft. Twenty-seven separate tests are reported here and include experiments with {sup 3}H, {sup 22}Na, {sup 241}Am, {sup 239}Np, {sup 228}Th, {sup 232}U and {sup 241}Pu, and two brine types, AIS and ERDA 6. The {sup 3}H was bound as water and provides a measure of advection, dispersion, and water self-diffusion. The other tracers were injected as dissolved ions at concentrations below solubility limits, except for americium. The objective of the intact rock column flow experiments is to demonstrate and quantify transport retardation coefficients, (R) for the actinides Pu, Am, U, Th and Np, in intact core samples of the Culebra Dolomite. The measured R values are used to estimate partition coefficients, (kd) for the solute species. Those kd values may be compared to values obtained from empirical and mechanistic adsorption batch experiments, to provide predictions of actinide retardation in the Culebra. Three parameters that may influence actinide R values were varied in the experiments; core, brine and flow rate. Testing five separate core samples from four different core borings provided an indication of sample variability. While most testing was performed with Culebra brine, limited tests were carried out with a Salado brine to evaluate the effect of intrusion of those lower waters. Varying flow rate provided an indication of rate dependent solute interactions such as sorption kinetics.

  3. Surface association of motile bacteria and apparent tortuosity values in packed column experiments

    NASA Astrophysics Data System (ADS)

    Narayanaswamy, Karthik; Ford, Roseanne M.; Smith, James A.; Fernandez, Erik J.

    2009-07-01

    Mathematical models used previously to obtain transport parameters from experimental investigations of bacterial transport in packed columns by Olson et al. (2005) yielded apparent tortuosity values that were an order of magnitude higher than expected for packed beds. The association of motile bacteria with solid surfaces of porous media, due to their swimming, contributed to the large apparent tortuosity values evaluated from packed column experiments; a modification of the transport equations to account for surface association yielded tortuosity values that were physically more reasonable. Although it was not possible to uniquely determine values of the kinetic parameters for surface association because of limitations with the experimental methods used by Olson et al., it was possible to constrain the range of values. A theoretical derivation of the mean residence time for swimming bacteria at a surface provided qualitative and quantitative support for including surface association terms in the transport model. This analysis shows that surface association can be a significant factor in modeling bacterial migration, and consideration of bacterial swimming properties such as run lengths and turn angles is important for predicting bacterial transport in saturated granular media typical of groundwater environments.

  4. Non-isothermal infiltration and tracer transport experiments on large soil columns

    NASA Astrophysics Data System (ADS)

    Sobotkova, Martina; Snehota, Michal; Cejkova, Eva; Tesar, Miroslav

    2016-04-01

    Isothermal and non-isothermal infiltration experiments were carried out in the laboratory on large undisturbed soil columns (19 cm in diameter, 25 cm high) taken at the experimental catchments Roklan (Sumava Mountains, Czech Republic) and Uhlirska (Jizera Mountains, Czech republic). The aim of the study was twofold. The first goal was to obtain water flow and heat transport data for indirect parameter estimation of thermal and hydraulic properties of soils from two sites by inverse modelling. The second aim was to investigate the extent of impact of the temperature on saturated hydraulic conductivity (Ksat) and dispersity of solute transport. The temperature of infiltrating water in isothermal experiment (20 °C) was equal to the initial temperature of the sample. For non-isothermal experiment water temperature was 5°C, while the initial temperature of the sample was 20°C as in previous case. The experiment was started by flooding the sample surface. Then water level was maintained at constant level throughout the infiltration run using the optical sensor and peristaltic pump. Concentration pulse of deuterium was applied at the top of the soil sample, during the steady state flow. Initial pressure head in the sample was close to field capacity. Two tensiometers and two temperature sensors were inserted in the soil sample in two depths (9 and 15 cm below the top of the sample). Two additional temperature sensors monitored the temperature entering and leaving the samples. Water drained freely through the perforated plate at the bottom of sample by gravity. Inflow and outflow water flux densities, water pressure heads and soil temperatures were monitored continuously during experiments. Effluent was sampled in regular time intervals and samples were analysed for deuterium concentrations by laser spectroscopy to develop breakthrough curves. The outcome of experiments are the series of measured water fluxes, pressure heads and temperatures ready for inverse modelling

  5. Importance of reversible attachment in predicting E. coli transport in saturated aquifers from column experiments

    NASA Astrophysics Data System (ADS)

    Knappett, P. S. K.; Du, J.; Liu, P.; Horvath, V.; Mailloux, B. J.; Feighery, J.; van Geen, A.; Culligan, P. J.

    2014-01-01

    Drinking water wells indiscriminatingly placed adjacent to fecal contaminated surface water represents a significant but difficult to quantify health risk. Here we seek to understand mechanisms that limit the contamination extent by scaling up bacterial transport results from the laboratory to the field in a well constrained setting. Three pulses of Escherichia coli originating during the early monsoon from a freshly excavated pond receiving latrine effluent in Bangladesh were monitored in 6 wells and modeled with a two-dimensional (2-D) flow and transport model conditioned with measured hydraulic heads. The modeling was performed assuming three different modes of interaction of E. coli with aquifer sands: (1) irreversible attachment only (best-fit ki = 7.6 day-1); (2) reversible attachment only (ka = 10.5 and kd = 0.2 day-1); and (3) a combination of reversible and irreversible modes of attachment (ka = 60, kd = 7.6, ki = 5.2 day-1). Only the third approach adequately reproduced the observed temporal and spatial distribution of E. coli, including a 4-log10 lateral removal distance of ˜9 m. In saturated column experiments, carried out using aquifer sand from the field site, a combination of reversible and irreversible attachment was also required to reproduce the observed breakthrough curves and E. coli retention profiles within the laboratory columns. Applying the laboratory-measured kinetic parameters to the 2-D calibrated flow model of the field site underestimates the observed 4-log10 lateral removal distance by less than a factor of two. This is promising for predicting field scale transport from laboratory experiments.

  6. Importance of Reversible Attachment in Predicting E. Coli Transport in Saturated Aquifers From Column Experiments.

    PubMed

    Knappett, P S K; Du, J; Liu, P; Horvath, V; Mailloux, B J; Feighery, J; van Geen, A; Culligan, P J

    2014-01-01

    Drinking water wells indiscriminatingly placed adjacent to fecal contaminated surface water represents a significant but difficult to quantify health risk. Here we seek to understand mechanisms that limit the contamination extent by scaling up bacterial transport results from the laboratory to the field in a well constrained setting. Three pulses of E. coli originating during the early monsoon from a freshly excavated pond receiving latrine effluent in Bangladesh were monitored in 6 wells and modeled with a two-dimensional (2-D) flow and transport model conditioned with measured hydraulic heads. The modeling was performed assuming three different modes of interaction of E. coli with aquifer sands: 1) irreversible attachment only (best-fit ki=7.6 day(-1)); 2) reversible attachment only (ka=10.5 and kd=0.2 day(-1)); and 3) a combination of reversible and irreversible modes of attachment (ka=60, kd=7.6, ki=5.2 day(-1)). Only the third approach adequately reproduced the observed temporal and spatial distribution of E. coli, including a 4-log10 lateral removal distance of ∼9 m. In saturated column experiments, carried out using aquifer sand from the field site, a combination of reversible and irreversible attachment was also required to reproduce the observed breakthrough curves and E. coli retention profiles within the laboratory columns. Applying the laboratory-measured kinetic parameters to the 2-D calibrated flow model of the field site underestimates the observed 4-log10 lateral removal distance by less than a factor of two. This is promising for predicting field scale transport from laboratory experiments.

  7. Importance of Reversible Attachment in Predicting E. Coli Transport in Saturated Aquifers From Column Experiments

    PubMed Central

    Knappett, P. S. K.; Du, J.; Liu, P.; Horvath, V.; Mailloux, B. J.; Feighery, J.; van Geen, A.; Culligan, P. J.

    2014-01-01

    Drinking water wells indiscriminatingly placed adjacent to fecal contaminated surface water represents a significant but difficult to quantify health risk. Here we seek to understand mechanisms that limit the contamination extent by scaling up bacterial transport results from the laboratory to the field in a well constrained setting. Three pulses of E. coli originating during the early monsoon from a freshly excavated pond receiving latrine effluent in Bangladesh were monitored in 6 wells and modeled with a two-dimensional (2-D) flow and transport model conditioned with measured hydraulic heads. The modeling was performed assuming three different modes of interaction of E. coli with aquifer sands: 1) irreversible attachment only (best-fit ki=7.6 day-1); 2) reversible attachment only (ka=10.5 and kd=0.2 day-1); and 3) a combination of reversible and irreversible modes of attachment (ka=60, kd=7.6, ki=5.2 day-1). Only the third approach adequately reproduced the observed temporal and spatial distribution of E. coli, including a 4-log10 lateral removal distance of ∼9 m. In saturated column experiments, carried out using aquifer sand from the field site, a combination of reversible and irreversible attachment was also required to reproduce the observed breakthrough curves and E. coli retention profiles within the laboratory columns. Applying the laboratory-measured kinetic parameters to the 2-D calibrated flow model of the field site underestimates the observed 4-log10 lateral removal distance by less than a factor of two. This is promising for predicting field scale transport from laboratory experiments. PMID:24821993

  8. The Use of Narratives to Contextualize the Experiences and Needs of Unemployed, Underemployed, and Displaced Workers

    ERIC Educational Resources Information Center

    Russell, Jessica C.

    2011-01-01

    The author examined the role of narratives used by unemployed, underemployed, and displaced workers seeking job training assistance through a government-funded One-Stop Career Center. Interviews with employees of a One-Stop Career Center provided insight on client rate of disclosure of personal narratives and how client narratives are used to…

  9. Mimicking pestcide percolation dynamics in ditches bed by successive column infltration experiment

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    Microbially mediated Cr(VI) reduction at the Hanford 100H area was investigated by flow-through column experiments. Three separate experiments were conducted to promote microbial activities associated with denitrification, iron and sulfate reduction, respectively. Replicate columns packed with natural sediments from the site under anaerobic environment were injected with 5mM Lactate as the electron donor and 5 μM Cr(VI) in all experiments. Sulfate and nitrate solutions were added to act as the main electron acceptors in the respective experiments, while iron columns relied on the indigenous sediment iron (and manganese) oxides as electron acceptors. Column effluent solutions were analyzed by IC and ICP-MS to monitor the microbial consumption/conversion of lactate and the associated Cr(VI) reduction. Biogeochemical reactive transport modeling was performed to gain further insights into the reaction mechanisms and Cr(VI) bioreduction rates. All experimental columns showed a reduction of the injected Cr(VI). Columns under denitrifying conditions showed the least Cr(VI) reduction at early stages (<60 days) compared to columns run under other experimental conditions, but became more active over time, and ultimately showed the most consistent Cr(VI) reduction. A strong correlation between denitrification and Cr(VI) reduction processes was observed and was in agreement with the results obtained in batch experiments with a denitrifying bacterium isolated from the Hanford site. The accumulation of nitrite does not appear to have an adverse effect on Cr(VI) reduction rates. Reactive transport simulations indicated that biomass growth completely depleted influent ammonium, and called for an additional source of N to account for the measured reduction rates. Iron columns were the least active with undetectable consumption of the injected lactate, slowest cell growth, and the smallest change in Cr(VI) concentrations during the course of the experiment. In contrast, columns

  11. Applied the Column Experiment to study on the Physical Clogging Features of Groundwater Artificial Recharge

    NASA Astrophysics Data System (ADS)

    Nan, T.; Tian, Y.; Xing, G.; Shao, J.

    2015-12-01

    Abstract: With the completion of South-to-North Water Diversion Project in China. Except used as the industrial and domestic water, the rest of the water will be injected into the aquifers for recovering of groundwater level. Where the water can be injected and will the blockage happen during the injection time would be the key problems. Thus, a clogging test is designed for testing the reinjection property of different mediums. The clogging process of artificial recharge with sand was experimentally studied in laboratory using sand columns. The clogging degree was determined according to the changes of hydraulic conductivity and flow rate. In this experiment, two kinds of the medium are used, which are round gravel from Xihuang Village and the sands from Yongding riverbed. For simulation different injection conditions, two kinds of suspension are used as the reinjection water, which are 0.5g/l and 1g/l. The test device consists of sand column, water supply system, piezometer system and flow measuring system. By recording the piezometric head and flow in different designed time, the variation of permeability in different depth can be caculated. The permeability can be treat as an important indicator of blockage. The experimental results show that: the physical clogging speed is as twice as fast,when the medium is the sands from Yongding river and the concentration of suspended solids doubled. But there is little differences in physical clogging speed, when the medium is the round gravel from Xihuan village and the concentration of suspension doubled. Generally, the blockage would finish within 20 hours. When it finished, the permeability commonly drops 10%. And the blockage influnce range is about 10cm. Thus, water quantity, water quality and cost effectiveness should be considered to select the recharge place where the recharge speed and the clogging speed are optimized.

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

    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). Experimental conditions (flow path length, advection rate, and temperature) were manipulated to represent conditions similar to near shore tropical environments. HgCl2-poisoned controls were used to assess whether reactions were microbially mediated. Overall, significant correlations were found between oxygen consumption and N2 production. The N:O2 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 (1.9-fold). Oxic respiration increased quickly until advection reached 80 L m-2 h-1 and then plateaued at higher advection rates. Interestingly, denitrification peaked (up to 336 μmol N2 m-2 h-1) at intermediate advection rates (30-80 L m-2 h-1). We speculate that intermediate advection rates 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 shelves implying that carbonate sands may play a major, but as yet unquantified, role in oceanic nitrogen budgets.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. First results from a soft-x-ray laser experiment in a confined plasma column

    SciTech Connect

    Suckewer, S; Johnson, L C; Sato, K; Semet, A; Skinner, C H; Voorhees, D

    1982-04-01

    We present a description of the experimental set up and the first results from an experiment designed to achieve lasing action in the soft x-ray region of the spectrum. A 0.5 kJ CO/sub 2/ laser was focused into a target gas, typically CO/sub 2/, and the resulting plasma was confined in a 50 to 90 kG magnetic field. Spectroscopic diagnostics were used to monitor the n = 7 and n = 8 level populations of CVI as well as ultraviolet emission lines of CV and CIII, for different plasma conditions. We present data showing that as the confining magnetic field was increased, the plasma column diameter decreased, the CVI 3434 line intensity (7 ..-->.. 6 transition) increased and its decay time decreased consistent with earlier computer modeling. We also discuss the effect of the low intensity tail, normally present in CO/sub 2/ laser pulses, on the predicted population inversion. Analysis of the experimental data by computer simulation shows the range of expected total gain on the n = 3 to n = 2 transition at 182A in these experiments was G = 0.05 to 0.1 and the possibility for its significant increase.

  15. Bridging the gap between batch and column experiments: A case study of Cs adsorption on granite.

    PubMed

    Wang, Tsing-Hai; Li, Ming-Hsu; Teng, Shi-Ping

    2009-01-15

    Both batch and column methods are conventionally utilized to determine some critical parameters for assessing the transport of contaminants of concern. The validity of using these parameters is somewhat confusing, however, since outputs such as distribution coefficient (Kd) from these two approaches are often discrepant. To bridge this gap, all possible factors that might contribute to this discrepancy were thoroughly investigated in this report by a case study of Cs sorption to crushed granite under various conditions. Our results confirm an important finding that solid/liquid (S/L) ratio is the dominant factor responsible for this discrepancy. As long as the S/L ratio exceeds 0.25, a consistent Kd value can be reached by the two methods. Under these conditions (S/L ratios>0.25), the sorption capacity of the solid is about an order of magnitude less than that in low S/L ratios (<0.25). Although low sorption capacity is observed in the cases of high S/L ratios, the sorption usually takes place preferentially on the most favorable (thermodynamically stable) sorption sites to form a stronger binding. This is verified by our desorption experiments in which a linear isotherm feature is shown either in deionized water or in 1M of ammonium acetate solutions. It may be concluded that batch experiment with an S/L ratio exceeding 0.25 is crucial to obtain convincing Kd values for safety assessment of radioactive waste repository.

  16. Pollution attenuation by soils receiving cattle slurry after passage of a slurry-like feed solution. Column experiments.

    PubMed

    Núñez-Delgado, Avelino; López-Períago, Eugenio; Diaz-Fierros-Viqueira, Francisco

    2002-09-01

    Designing soil filtration systems or vegetated filter strips as a means of attenuating water pollution should take into account soil purging capacity. Here we report data on laboratory column trials used to investigate the capacity of a Hortic Anthrosol to attenuate contamination due to downward leaching from cattle slurry applied at the surface. The columns comprised 900 g of soil to a depth of about 20-25 cm, and had been used previously in an experiment involving passage of at least 5 pore volumes of an ion-containing cattle slurry-like feed solution. For the present experiments, the columns were first washed through with distilled water (simulating resting and rain falling after passage of the feed solution), and then received a single slurry dose equivalent to about 300 m3 ha(-1). The columns were then leached with distilled water, with monitoring of chemical oxygen demand (COD) and ion contents in outflow. The results indicated that the pollution-neutralising capacity of the soil was still high but clearly lower than in the earlier experiments with the feed solution. Furthermore, the time-course of COD showed that organic acids were leached through the column even more rapidly than chloride (often viewed as an inert tracer) enhancing the risk of heavy metals leaching and subsequent water pollution. Resting and alternate use of different soil-plant buffer zones would increase the lifespan of purging systems that use soil like the here studied one.

  17. Advanced landfill leachate treatment using iron-carbon microelectrolysis- Fenton process: Process optimization and column experiments.

    PubMed

    Wang, Liqun; Yang, Qi; Wang, Dongbo; Li, Xiaoming; Zeng, Guangming; Li, Zhijun; Deng, Yongchao; Liu, Jun; Yi, Kaixin

    2016-11-15

    A novel hydrogen peroxide-enhanced iron-carbon (Fe-C) microelectrolysis reactor was proposed for the pretreatment of mature landfill leachate. This reactor, combining microelectrolysis with Fenton process, revealed high treatment efficiency. The operating variables, including Fe-C dosage, H2O2 concentration and initial pH, were optimized by the response surface methodology (RSM), regarding the chemical oxygen demand (COD) removal efficiency and biochemical oxygen demand: chemical oxygen demand (BOD5/COD) as the responses. The highest COD removal (74.59%) and BOD5/COD (0.50) was obtained at optimal conditions of Fe-C dosage 55.72g/L, H2O2 concentration 12.32mL/L and initial pH 3.12. Three-dimensional excitation and emission matrix (3D-EEM) fluorescence spectroscopy and molecular weight (MW) distribution demonstrated that high molecular weight fractions such as refractory fulvic-like substances in leachate were effectively destroyed during the combined processes, which should be attributed to the combination oxidative effect of microelectrolysis and Fenton. The fixed-bed column experiments were performed and the breakthrough curves at different flow rates were evaluated to determine the practical applicability of the combined process. All these results show that the hydrogen peroxide-enhanced iron-carbon (Fe-C) microelectrolysis reactor is a promising and efficient technology for the treatment of mature landfill leachate. PMID:27450338

  18. Column experiments to investigate transport of colloidal humic acid through porous media during managed aquifer recharge

    NASA Astrophysics Data System (ADS)

    Liu, Dan; Zhou, Jingjing; Zhang, Wenjing; Huan, Ying; Yu, Xipeng; Li, Fulin; Chen, Xuequn

    2016-09-01

    Colloids act as vectors for pollutants in groundwater, thereby creating a series of environmental problems. While managed aquifer recharge plays an important role in protecting groundwater resources and controlling land subsidence, it has a significant effect on the transport of colloids. In this study, particle size and zeta potential of colloidal humic acid (HA) have been measured to determine the effects of different hydrochemistry conditions. Column experiments were conducted to examine the effects on the transport of colloidal HA under varying conditions of pH (5, 7, 9), ionic strength (<0.0005, 0.02, 0.05 M), cation valence (Na+, Ca2+) and flow rate (0.1, 0.2, 0.4 ml/min) through collectors (glass beads) to model the properties and quality of artificial recharge water and changes in the hydrodynamic field. Breakthrough curves showed that the behavior of colloidal HA being transported varied depending on the conditions. Colloid transport was strongly influenced by hydrochemical and hydrodynamic conditions. With decreasing pH or increasing ionic strength, a decrease in the peak effluent concentration of colloidal HA and increase in deposition could be clearly seen. Comparison of different cation valence tests indicated that changes in transport and deposition were more pronounced with divalent Ca2+ than with monovalent Na+. Changes in hydrodynamic field (flow rate) also had an impact on transportation of colloidal HA. The results of this study highlight the need for further research in this area.

  19. Accumulation of pharmaceuticals in groundwater under arid climate conditions - Results from unsaturated column experiments.

    PubMed

    Zemann, M; Majewsky, M; Wolf, L

    2016-07-01

    Intense reuse of treated wastewater in agriculture is practiced all over the world, especially in arid and water-scarce regions. In doing so, pharmaceutical residues in the water are irrigated to the soil and subsequently can percolate into the local aquifers. Since evaporation rates in these areas are typically high, persistent substances might enrich in the groundwater recharge of closed catchments like the Jordan Valley. Against this background, unsaturated column tests were conducted to investigate the potential for evaporative accumulation of the two pharmaceuticals bezafibrate and carbamazepine under simulated arid climate conditions. Parallel tests were conducted with inhibited microbiological activity where both substances showed an increase in the effluent concentrations proportional to the evaporation loss of the inflow solution. The mean accumulation factors of the pharmaceuticals correspond to the evaporated water loss. The experiments indicate the accumulation potential for pharmaceuticals with high persistence against biodegradation. For the first time, the overall potential for evaporative enrichment could be demonstrated for pharmaceuticals. Under the given experimental conditions, the two investigated pharmaceuticals did not enrich faster than chloride, which might result in soil salting prior to reaching harmful pharmaceutical concentrations in soil water. The findings are relevant to future assessments of environmental impacts of persistent trace substances, which need to take into account that concentrations in the aquatic cycle might increase further due to evaporative enrichment. PMID:27085060

  20. Rise characteristics of gas bubbles in a 2D rectangular column: VOF simulations vs experiments

    SciTech Connect

    Krishna, R.; Baten, J.M. van

    1999-10-01

    About five centuries ago, Leonardo da Vinci described the sinuous motion of gas bubbles rising in water. The authors have attempted to simulate the rise trajectories of bubbles of 4, 5, 7, 8, 9, 12, and 20 mm in diameter rising in a 2D rectangular column filled with water. The simulations were carried out using the volume-of-fluid (VOF) technique developed by Hirt and Nichols (J. Computational Physics, 39, 201--225 (1981)). To solve the Navier-Stokes equations of motion the authors used a commercial solver, CFX 4.1c of AEA Technology, UK. They developed their own bubble-tracking algorithm to capture sinuous bubble motions. The 4 and 5 mm bubbles show large lateral motions observed by Da Vinci. The 7, 8 and 9 mm bubble behave like jellyfish. The 12 mm bubble flaps its wings like a bird. The extent of lateral motion of the bubbles decreases with increasing bubble size. Bubbles larger than 20 mm in size assume a spherical cap form and simulations of the rise characteristics match experiments exactly. VOF simulations are powerful tools for a priori determination of the morphology and rise characteristics of bubbles rising in a liquid. Bubble-bubble interactions are also properly modeled by the VOF technique.

  1. A Single Column Model Ensemble Approach Applied to the TWP-ICE Experiment

    SciTech Connect

    Davies, Laura; Jakob, Christian; Cheung, K.; Del Genio, Anthony D.; Hill, Adrian; Hume, Timothy; Keane, R. J.; Komori, T.; Larson, Vincent E.; Lin, Yanluan; Liu, Xiaohong; Nielsen, Brandon J.; Petch, Jon C.; Plant, R. S.; Singh, M. S.; Shi, Xiangjun; Song, X.; Wang, Weiguo; Whitall, M. A.; Wolf, A.; Xie, Shaocheng; Zhang, Guang J.

    2013-06-27

    Single column models (SCM) are useful testbeds for investigating the parameterisation schemes of numerical weather prediction and climate models. The usefulness of SCM simulations are limited, however, by the accuracy of the best-estimate large-scale data prescribed. One method to address this uncertainty is to perform ensemble simulations of the SCM. This study first derives an ensemble of large-scale data for the Tropical Warm Pool International Cloud Experiment (TWP-ICE) based on an estimate of a possible source of error in the best-estimate product. This data is then used to carry out simulations with 11 SCM and 2 cloud-resolving models (CRM). Best-estimate simulations are also performed. All models show that moisture related variables are close to observations and there are limited differences between the best-estimate and ensemble mean values. The models, however, show different sensitivities to changes in the forcing particularly when weakly forced. The ensemble simulations highlight important differences in the moisture budget between the SCM and CRM. Systematic differences are also apparent in the ensemble mean vertical structure of cloud variables. The ensemble is further used to investigate relations between cloud variables and precipitation identifying large differences between CRM and SCM. This study highlights that additional information can be gained by performing ensemble simulations enhancing the information derived from models using the more traditional single best-estimate simulation.

  2. Competitive adsorption and selectivity sequence of heavy metals by chicken bone-derived biochar: Batch and column experiment.

    PubMed

    Park, Jong-Hwan; Cho, Ju-Sik; Ok, Yong Sik; Kim, Seong-Heon; Kang, Se-Won; Choi, Ik-Won; Heo, Jong-Soo; DeLaune, Ronald D; Seo, Dong-Cheol

    2015-01-01

    The objective of this research was to evaluate adsorption of heavy metals in single- and ternary-metal forms onto chicken bone biochar (CBB). Competitive sorption of heavy metals by CBB has never been reported previously. The maximum adsorption capacities of metals by CBB were in the order of Cu (130 mg g(-1)) > Cd (109 mg g(-1)) > Zn (93 mg g(-1)) in the single-metal adsorption isotherm and Cu (108 mg g(-1)) > Cd (54 mg g(-1)) ≥ Zn (44 mg g(-1)) in the ternary-metal adsorption isotherm. Cu was the most retained cation, whereas Zn could be easily exchanged and substituted by Cu. Batch experimental data best fit the Langmuir model rather than the Freundlich isotherms. In the column experiments, the total adsorbed amounts of the metals were in the following order of Cu (210 mg g(-1)) > Cd (192 mg g(-1)) > Zn (178) in single-metal conditions, and Cu (156) > Cd (123) > Zn (92) in ternary-metal conditions. Results from both the batch and column experiments indicate that competitive adsorption among metals increases the mobility of these metals. Especially, Zn in single-metal conditions lost it adsorption capacity most significantly. Based on the 3D simulation graphs of heavy metals, adsorption patterns under single adsorption condition were different than under competitive adsorption condition. Results from both the batch and column experiments show that competitive adsorption among metals increases the mobility of these metals. The maximum metal adsorption capacity of the metals in the column experiments was higher than that in the batch experiment indicating other metal retention mechanisms rather than adsorption may be involved. Therefore, both column and batch experiments are needed for estimating retention capacities and removal efficiencies of metals in CBB.

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

    ERIC Educational Resources Information Center

    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…

  4. Column experiments to study nonlinear removal of bacteriophages by passage through saturated dune sand

    NASA Astrophysics Data System (ADS)

    Schijven, J. F.; Hassanizadeh, S. M.; de Bruin, H. A. M.

    2002-10-01

    In a recent field study on dune recharge, bacteriophages MS2 and PRD1 were found to be removed 3 log 10 over the first 2.4 m and only 5 log 10 over the next 27 m. To understand the causes of this nonlinear removal, column experiments were carried out under conditions similar to the field: same recharge water, temperature (5±3 °C) and pore water velocity (1.5 m day -1). Soil samples were taken along a streamline between the recharge canal and the first monitoring well. Bacteriophage φX174 was included for comparison. The high initial removal in the field was found not to be due to heterogeneity of phage suspensions but to soil heterogeneity. Phage removal rates correlated strongly positively with soil organic carbon content, and relatively strongly positively with silt content and the presence of ferric oxyhydroxides. Soil organic carbon content, silt content and the presence of ferric oxyhydroxides were found to decrease exponentially with travel distance. Removal rates of φX174 were found to be 3-10 times higher than those of MS2 and PRD1 due to the lower electrostatic repulsion that the less negatively charged φX174 experiences. It is suggested that the high initial removal in the field is due to the presence of favorable sites for attachment formed by ferric oxyhydroxides that decrease exponentially with travel distance. Similar removal rates may be found at both laboratory and field scale. However, due to local variations at field scale detailed knowledge on soil heterogeneity may be needed to enable a reliable prediction of removal.

  5. Effect of the pressure on pre-column sample dispersion theory, experiments, and practical consequences.

    PubMed

    Gritti, Fabrice; Guiochon, Georges

    2014-07-25

    The effect of the pressure on the dispersion of a low molecular weight compound along 0.508 and 1.016 mm i.d. × 50 cm long open circular tubes was investigated theoretically and experimentally. The theoretical predictions were based on the early models of dispersion derived by Aris and Taylor (1953) and on the approximate model of Alizadeh for the time moments (1980). Experimentally, the system pressure was increased at constant flow rate (0.15 mL/min) from less than 20 to nearly 1,000 bar by using a series of capillary tubes (25 μm i.d. PEEKSIL tubes) of increasing flow resistances placed upstream the detection cell of a commercial very high pressure liquid chromatograph (vHPLC) but downstream the 50 cm long tube. Theoretical and experimental results agree that the peak variance increases linearly with increasing pressure in the tube volume. The relative increase of the peak variance is 7% above that measured at low pressure (<20 bar) for each 100 bar increment in the tube volume. This result confirms that accurate measurements of the column efficiency corrected for extra-column contribution cannot be made by replacing the column with a zero dead volume union connector, because the pressures applied in the pre-column volume are significantly different in these two cases. This work shows also that increasing the pressure in the pre-column volume by increasing the flow rate affects the apparent column efficiency that is measured, independently of the direct effect of the flow rate. For a 2.1 × 50mm column packed with 1.3 μm core-shell particles run with a classic Acquity system, the associated relative decreases of the column efficiency are expected to be -30%, -20%, and -5% for retention factors of 1, 3, and 10, respectively. The column HETP is no longer independent of its length.

  6. Natural attenuation of pharmaceuticals and an illicit drug in a laboratory column experiment.

    PubMed

    Greenhagen, Andrew M; Lenczewski, Melissa E; Carroll, Monica

    2014-11-01

    Trace amounts of pharmaceutical compounds have been detected in waters across the United States. Many compounds are released as the result of human ingestion and subsequent excretion of over-the-counter and prescription medications, and illicit drugs. This research utilized columns (30×30cm) of sand and undisturbed fine-grained sediments to simulate injection of wastewater containing pharmaceuticals and an illicit drug, such as would be found in a septic system, leaky sewer, or landfill. The columns were placed in a temperature-controlled laboratory and each was injected with natural groundwater containing known concentrations of caffeine, methamphetamine, and acetaminophen. Natural attenuation of each chemical was observed in all columns. The highest amount removed (approximately 90%) occurred in the undisturbed column injected with methamphetamine, compared with little reduction in the sand column. When the suite of drugs was injected, loss of methamphetamine was less than when methamphetamine was injected alone. The subsurface sediments exhibit the ability to remove a substantial amount of the injected pharmaceuticals and illicit drug; however, complete removal was not achieved. There was little attenuation of injected pharmaceuticals in the sand column which demonstrates a concern for water quality in the environment if pharmaceuticals were to contaminate a sandy aquifer. Understanding the transport of pharmaceuticals in the subsurface environment is an important component of protecting drinking water supplies from contamination.

  7. Determination of water content by TDR during the infiltration outflow column experiment

    NASA Astrophysics Data System (ADS)

    Sobotkova, M.; Snehota, M.; Klipa, V.

    2012-04-01

    Pore system of some soils may not become fully saturated during ponded infiltration due to air entrapment. Varying entrapped air content then determines quasi-saturated water content of soil and can strongly affect soil quasi-saturated hydraulic conductivity. This study shows changes of quasi-saturated volumetric water content in time measured by time domain reflectometry (TDR) during the infiltration outflow experiment conducted on medium sized soil column in the laboratory. Experiments were conducted on a packed sample of fine quartz sand and on undisturbed soil. The undisturbed soil sample (internal diameter 189 mm and 250 mm height) of sandy loam soil was collected at the experimental site Uhlirska (Jizera Mountains, Czech Republic). Recurrent ponded infiltration experiment, conducted on each sample, consisted of three infiltration runs. The same level of ponding was maintained during each infiltration run at the top of the sample. Water drained freely through the perforated plate at the bottom of the sample. First infiltration run was done into naturally dry soil while subsequent runs were conducted into wet soil. The degassed water was used for the third infiltration run. The apparent dielectric constants were monitored at depths 75, 125 and 175 mm bellow the sample surface using the 7.5 cm long TDR probes connected to Campbell Scientific TDR100 reflectometer via multiplexor. Volumetric water contents in each depth were calculated from apparent dielectric constants using Topp's equation. Additionally, the pulse of potassium bromide was applied repeatedly during the quasi-steady state of each infiltration run, while the bromide breakthrough was monitored both in the effluent (by ion selective electrode) and in the sample by TDR (as changes of electric conductivity). Experimental results showed that in case of homogenously packed sand the quasi-steady state flow rates and water contents were nearly the same during all three infiltration runs. The undisturbed

  8. Transport and sorption behavior of individual phthalate esters in sandy aquifer: column experiments.

    PubMed

    Zakari, Sissou; Liu, Hui; Li, Yan-Xi; He, Xi; Tong, Lei

    2016-08-01

    This work aimed to quantify the transport and sorption behavior of four individual phthalate esters (PAEs) in sandy aquifer using column experiments so as to provide important parameters for the prediction and control of PAEs pollution plume in groundwater system. The transport curves of four individual PAEs were simulated with HYDRUS-1D through fitting linear and nonlinear equilibrium (LE/NO), linear and nonlinear, first-order, one-site non-equilibrium (LO/NO), linear and nonlinear, first-order, two-site non-equilibrium (LFO/NFO) sorption models. Simulation results showed that two-site models (LFO and NFO) displayed similar best fittings. The results from LFO model simulation showed that when water flowed 1000 m in sandy aquifer, PAEs with shorter carbon chains (DMP and DEP) transport 31.6 and 22.2 m, respectively. Unexpectedly for the same water transport distance, PAEs with longer carbon chains (DBP and DiBP) transported 40.2 and 60.7 m, respectively, which were faster than DMP and DEP, mainly due to the limited accessibility of type-2 sorption sites. The retardations were mainly caused by the sorption of PAEs on the time-dependent type-2 sites. DBP and DiBP exhibited higher mass transfer speed to and fro type-2 sites but showed lower total sorption coefficient (K) due to the limited accessibility of sorption sites. Coexistence of PAEs and smaller sorbent particles increased total K values of DBP and DiBP due to synergic development of more sorption sites with DMP and DEP. PMID:27146532

  9. A Single-column Model Ensemble Approach Applied to the TWP-ICE Experiment

    NASA Technical Reports Server (NTRS)

    Davies, L.; Jakob, C.; Cheung, K.; DelGenio, A.; Hill, A.; Hume, T.; Keane, R. J.; Komori, T.; Larson, V. E.; Lin, Y.; Liu, X.; Nielsen, B. J.; Petch, J.; Plant, R. S.; Singh, M. S.; Shi, X.; Song, X.; Wang, W.; Whithall, M. A.; Wolf, A.; Xie, S.; Zhang, G.

    2013-01-01

    Single-column models (SCM) are useful test beds for investigating the parameterization schemes of numerical weather prediction and climate models. The usefulness of SCM simulations are limited, however, by the accuracy of the best estimate large-scale observations prescribed. Errors estimating the observations will result in uncertainty in modeled simulations. One method to address the modeled uncertainty is to simulate an ensemble where the ensemble members span observational uncertainty. This study first derives an ensemble of large-scale data for the Tropical Warm Pool International Cloud Experiment (TWP-ICE) based on an estimate of a possible source of error in the best estimate product. These data are then used to carry out simulations with 11 SCM and two cloud-resolving models (CRM). Best estimate simulations are also performed. All models show that moisture-related variables are close to observations and there are limited differences between the best estimate and ensemble mean values. The models, however, show different sensitivities to changes in the forcing particularly when weakly forced. The ensemble simulations highlight important differences in the surface evaporation term of the moisture budget between the SCM and CRM. Differences are also apparent between the models in the ensemble mean vertical structure of cloud variables, while for each model, cloud properties are relatively insensitive to forcing. The ensemble is further used to investigate cloud variables and precipitation and identifies differences between CRM and SCM particularly for relationships involving ice. This study highlights the additional analysis that can be performed using ensemble simulations and hence enables a more complete model investigation compared to using the more traditional single best estimate simulation only.

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

    NASA Astrophysics Data System (ADS)

    Rieckh, Helene; Gerke, Horst; Glæsner, Nadia; Kjaergaard, Charlotte; Sommer, Michael

    2014-05-01

    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 (20-40 cm and 40-60 cm) horizons of the eroded Haplic Luvisol and Ap (0-20 cm) and CBkg (20-40 cm) horizon of the Haplic Regosol. Leaching experiments were performed on intact soil columns (20 cm diameter, 20 cm height) and carried out during unsaturated conditions with a suction applied at the lower 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 heterogeneity of the Luvisol bulk density. The active flow volume was smaller for the Regosol horizons both in 0-20 cm and 20-40 cm depths. The highest DOC leaching was from the E horizon (20-40 cm depth) located just underneath the Ap horizon of the Luvisol corresponding with its lower clay content. From the finding of a substantially lower leaching of particles from all Regosol horizons, we assume a lower transport of particulate C from the Haplic Regosol than from the eroded Haplic Luvisol. Results suggest that soil erosion not only affected the pedological structure and physical soil properties but also strongly the water and solute movement.

  11. GRAVI-2 space experiment: investigating statoliths displacement and location effects on early stages of gravity perception pathways in lentil roots.

    NASA Astrophysics Data System (ADS)

    Bizet, François; Eche, Brigitte; Pereda Loth, Veronica; Badel, Eric; Legue, Valerie; Brunel, Nicole; Label, Philippe; Gérard, Joëlle

    2016-07-01

    The plants ability to orient their growth with respect to external stimuli such as gravity is a key factor for survival and acclimation to their environment. Belowground, plant roots modulate their growth towards gravity, allowing soil exploration and uptake of water and nutrients. In roots, gravity sensing cells called statocytes are located in the center of the root cap. Statocytes contain starch-filled plastids denser than the cytoplasm, which sedimentation along the direction of gravity is widely accepted as being involved into early stages of gravity perception (the starch-statolith hypothesis; Sack, 1991). Root gravitropism following statoliths displacement is based on auxin redistribution in the root apex, inducing differential growth between the root upward and downward sides. However at the cell scale, the chain of transduction starting from statoliths displacement and leading to auxin redistribution remains poorly documented. Signaling molecules such as calcium, reactive oxygen species, nitric oxide and inositol 1,4,5-triphosphate are serious candidates previously shown to be involved within minutes before modification of the expression of auxin-related genes (Morita, 2010; Sato et al., 2015). Here, we observe and quantify statoliths displacements and locations at various levels of gravity to investigate two hypothesis: (i) Are contacts between statoliths and the endoplasmic reticulum necessary to induce gravitropism? (ii) Are very low displacements of statoliths sufficient to initiate transduction pathways such as the calcium's one? These questionings have led to an experiment called GRAVI-2 which took place aboard the ISS in 2014. During the experiment, lentil roots were grown in the European modular cultivation system for several hours in microgravity and were then submitted to short high gravity stimulus (5 and 15 minutes at 2 g) before the return to Earth for analyses. Ongoing cytological measurements will reveal the effects of statoliths

  12. Specific yield - laboratory experiments showing the effect of time on column drainage

    USGS Publications Warehouse

    Prill, Robert C.; Johnson, A.I.; Morris, Donald Arthur

    1965-01-01

    The increasing use of ground water from many major aquifers in the United States has required a more thorough understanding of gravity drainage, or specific yield. This report describes one phase of specific yield research by the U.S. Geological Survey's Hydrologic Laboratory in cooperation with the California Department of Water Resources. An earlier phase of the research concentrated on the final distribution of moisture retained after drainage of saturated columns of porous media. This report presents the phase that concentrated on the distribution of moisture retained in similar columns after drainage for various periods of time. Five columns, about 4 cm in diameter by 170 cm long, were packed with homogenous sand of very fine, medium, and coarse sizes, and one column was packed with alternating layers of coarse and medium sand. The very fine materials were more uniform in size range than were the medium materials. As the saturated columns drained, tensiometers installed throughout the length recorded changes in moisture tension. The relation of tension to moisture content, determined for each of the materials, was then used to convert the tension readings to moisture content. Data were then available on the distribution of retained moisture for different periods of drainage from 1 to 148 hours. Data also are presented on the final distribution of moisture content by weight and volume and on the degree of saturation. The final zone of capillary saturation was approximately 12 cm for coarse sand, 13 cm for medium sand, and 52 cm for very fine sand. The data showed these zones were 92 to 100 percent saturated. Most of the outflow from the columns occurred in the earlier hours of drainage--90 percent in 1 hour for the coarse materials, 50 percent for the medium, and 60 percent for the very fine. Although the largest percentage of the specific yield was reached during the early hours of .drainage, this study amply demonstrates that a very long time would be

  13. Integrating mental health into primary care for displaced populations: the experience of Mindanao, Philippines

    PubMed Central

    2011-01-01

    Background For more than forty years, episodes of violence in the Mindanao conflict have recurrently led to civilian displacement. In 2008, Medecins Sans Frontieres set up a mental health program integrated into primary health care in Mindanao Region. In this article, we describe a model of mental health care and the characteristics and outcomes of patients attending mental health services. Methods Psychologists working in mobile clinics assessed patients referred by trained clinicians located at primary level. They provided psychological first aid, brief psychotherapy and referral for severe patients. Patient characteristics and outcomes in terms of Self-Reporting Questionnaire (SRQ20) and Global Assessment of Functioning score (GAF) are described. Results Among the 463 adult patients diagnosed with a common mental disorder with at least two visits, median SRQ20 score diminished from 7 to 3 (p < 0.001) and median GAF score increased from 60 to 70 (p < 0.001). Baseline score and score at last assessment were different for both discharged patients and defaulters (p < 0.001). Conclusions Brief psychotherapy sessions provided at primary level during emergencies can potentially improve patients' symptoms of distress. PMID:21385338

  14. Influences of nanoscale zero valent iron loadings and bicarbonate and calcium concentrations on hydrogen evolution in anaerobic column experiments.

    PubMed

    Paar, Hendrik; Ruhl, Aki Sebastian; Jekel, Martin

    2015-01-01

    The estimation of nanoscale zero-valent iron (nZVI) reactivity after its injection into the subsurface is essential for its application in groundwater remediation. In the present study H₂ generation of commercially available nZVI and novel milled nZVI flakes were investigated in column experiments with varying nZVI loads (ranging from 8 to 43 g nZVI per kg sand). H₂ evolution rates were determined for column experiments without and with hydrogen carbonate and/or calcium. On average 0.29 mmol H₂/L per g Fe⁰ evolved within the first 30 days in column experiments with spherical, commercial nZVI particles. The H₂ evolution developed almost independently of the water matrices applied. The application of nZVI flakes resulted in lower H₂ generation rates. In general corrosion rates accelerated linearly with increasing initial amounts of iron. This was evident in experiments with both particle types. Concentration profiles of carbonate and calcium in influent and effluent were used to estimate corrosion products and precipitates. Despite the presence of high concentrations of inorganic carbon, Fe²⁺ reacted preferably with hydroxide ions to form ferrous hydroxide which is the precursor of magnetite. As a result only minor passivation of the reactive nZVI was observed. PMID:25462777

  15. Influences of nanoscale zero valent iron loadings and bicarbonate and calcium concentrations on hydrogen evolution in anaerobic column experiments.

    PubMed

    Paar, Hendrik; Ruhl, Aki Sebastian; Jekel, Martin

    2015-01-01

    The estimation of nanoscale zero-valent iron (nZVI) reactivity after its injection into the subsurface is essential for its application in groundwater remediation. In the present study H₂ generation of commercially available nZVI and novel milled nZVI flakes were investigated in column experiments with varying nZVI loads (ranging from 8 to 43 g nZVI per kg sand). H₂ evolution rates were determined for column experiments without and with hydrogen carbonate and/or calcium. On average 0.29 mmol H₂/L per g Fe⁰ evolved within the first 30 days in column experiments with spherical, commercial nZVI particles. The H₂ evolution developed almost independently of the water matrices applied. The application of nZVI flakes resulted in lower H₂ generation rates. In general corrosion rates accelerated linearly with increasing initial amounts of iron. This was evident in experiments with both particle types. Concentration profiles of carbonate and calcium in influent and effluent were used to estimate corrosion products and precipitates. Despite the presence of high concentrations of inorganic carbon, Fe²⁺ reacted preferably with hydroxide ions to form ferrous hydroxide which is the precursor of magnetite. As a result only minor passivation of the reactive nZVI was observed.

  16. Consolidated Fuel Reprocessing Program. Operating experience with pulsed-column holdup estimators

    SciTech Connect

    Ehinger, M.H.

    1986-01-01

    Methods for estimating pulsed-column holdup are being investigated as part of the Safeguards Assessment task of the Consolidated Fuel Reprocessing Program (CFRP) at the Oak Ridge National Laboratory. The CFRP was a major sponsor of test runs at the Barnwell Nuclear Fuel plant (BNFP) in 1980 and 1981. During these tests, considerable measurement data were collected for pulsed columns in the plutonium purification portion of the plant. These data have been used to evaluate and compare three available methods of holdup estimation.

  17. Computational experience with a dense column feature for interior-point methods

    SciTech Connect

    Wenzel, M.; Czyzyk, J.; Wright, S.

    1997-08-01

    Most software that implements interior-point methods for linear programming formulates the linear algebra at each iteration as a system of normal equations. This approach can be extremely inefficient when the constraint matrix has dense columns, because the density of the normal equations matrix is much greater than the constraint matrix and the system is expensive to solve. In this report the authors describe a more efficient approach for this case, that involves handling the dense columns by using a Schur-complement method and conjugate gradient interaction. The authors report numerical results with the code PCx, into which the technique now has been incorporated.

  18. Effect of gravity on colloid transport through water-saturated columns packed with glass beads: modeling and experiments.

    PubMed

    Chrysikopoulos, Constantinos V; Syngouna, Vasiliki I

    2014-06-17

    The role of gravitational force on colloid transport in water-saturated columns packed with glass beads was investigated. Transport experiments were performed with colloids (clays: kaolinite KGa-1b, montmorillonite STx-1b). The packed columns were placed in various orientations (horizontal, vertical, and diagonal) and a steady flow rate of Q = 1.5 mL/min was applied in both up-flow and down-flow modes. All experiments were conducted under electrostatically unfavorable conditions. The experimental data were fitted with a newly developed, analytical, one-dimensional, colloid transport model. The effect of gravity is incorporated in the mathematical model by combining the interstitial velocity (advection) with the settling velocity (gravity effect). The results revealed that flow direction influences colloid transport in porous media. The rate of particle deposition was shown to be greater for up-flow than for down-flow direction, suggesting that gravity was a significant driving force for colloid deposition.

  19. Investigation of reactive transport with closed-flow column experiments and parallel factor analysis (PARAFAC) of fluorescence data

    NASA Astrophysics Data System (ADS)

    Ritschel, Thomas; Totsche, Kai Uwe

    2013-04-01

    The sorption of solutes and colloids to immobile sorbents results in the phenomenon of retardation. Besides the interactions at the sorbent-solution-interface, the sorption rate depends also on the spatial structure of the pore network (size distribution, connectivity, topology). Column experiments allow for the consideration of the structure and thus for a quantification of possible rate limitations. We focus on column experiments run in closed-flow mode. There, a typical oscillation in the "breakthrough" of solute concentration, which conveys additional information about the flow regime (dispersivity, water content, immobile water) as well as the effective interaction kinetics, can be observed. Another major feature of the closed flow design is the conservation of tracer mass inside the column setup. Therefore, the investigation of sorption characteristics can be simplified by using mass balances. Our objective is to study the interaction between different solutes (conservative tracers, e.g., NaCl or LiBr and reactive tracers, e.g., acetate, oxalate and phenanthrene) and artificial porous media (composed of quartz, illite, goethite and charcoal in a well defined grain size distribution). The concentration-time profile of solutes is measured with non-consuming techniques (fluorescence spectroscopy or electrical conductivity measurements). PARAFAC analysis of fluorescence data is used for the quantification of aromatic compounds in complex background solutions. Interaction parameters obtained from breakthrough data are then used to quantify the availability of reactive mineral surfaces and effective rates of physical and chemical non-equilibrium processes. After the column experiments, the effect on the microtopology and mineral surfaces is investigated by atomic force microscopy and scanning electron microscopy. Recent multi-step tracer experiments allowed for the reconstruction of adsorption isotherms of oxalate and acetate on goethite.

  20. Impact of sewage sludge spreading on nickel mobility in a calcareous soil: adsorption-desorption through column experiments.

    PubMed

    Mamindy-Pajany, Yannick; Sayen, Stéphanie; Guillon, Emmanuel

    2013-07-01

    A soil column adsorption-desorption study was performed on an agricultural calcareous soil to determine the impact of sewage sludge spreading on nickel mobility. Ni adsorption experiments were followed by desorption tests involving the following liquid extractants: water, calcium (100 mg/L), oxalic acid (525 mg/L equivalent to 100 mg carbon/L), and sludge extracts (0.5 and 2.5 g/L). Desorption tests were also conducted after sewage sludge spreading at three application rates (30, 75, and 150 t/ha). According to the breakthrough curve, Ni adsorption was irreversible and occurred mainly through interactions with calcite surface sites. Nickel desorption from the soil column was promoted in presence of significant dissolved organic carbon (DOC) concentration as observed with oxalic acid elution and sludge extract at 2.5 g/L. In sludge-amended soil columns, the maximum Ni levels occurred in first pore volumes, and they were positively correlated to the sludge application rate. The presence of DOC in leaching waters was the main factor controlling Ni desorption from the sludge-amended soil columns. This finding implies that DOC generated by sludge applied on calcareous soils might facilitate the leaching of Ni due to the formation of soluble Ni-organic complexes. Thus, sludge application can have potential environmental impacts in calcareous soils, since it promotes nickel transport by decreasing Ni retention by soil components.

  1. Ozonation products of carbamazepine and their removal from secondary effluents by soil aquifer treatment--indications from column experiments.

    PubMed

    Hübner, U; Seiwert, B; Reemtsma, T; Jekel, M

    2014-02-01

    Ozonation is known as an efficient treatment to reduce the concentration of many trace organic compounds from WWTP effluents, but the formation of unknown and possibly persistent and toxic transformation products has to be considered. In this paper tertiary treatment of wastewater by the combination of ozone and soil aquifer treatment was investigated with respect to the removal of the antiepileptic drug carbamazepine (CBZ, 10 μg/L) and its transformation products. Batch tests and pilot experiments confirmed efficient removal of carbamazepine from secondary effluent by ozone. With typical ozone consumption of 0.7 mg O3/mg DOC0, approx. 50% of the transformed CBZ was detected as its primary product 1-(2-benzaldehyde)-4-hydro-(1H,3H)-quinazoline-2-one (BQM). Structure proposals and a formation pathway were elaborated for a total of 13 ozonation products of CBZ. In subsequent biological treatment BQM turned out to be more effectively biodegraded than CBZ. Its aldehyde group was quickly oxidized to a carboxylic acid (BaQM), which was removed in sand column experiments. Most of the minor ozonation products of CBZ persisted in sand column experiments with residence times of 5-6 days. Non-target screening of column effluent revealed no formation of persistent biotransformation products.

  2. Education and/or Displacement? A Pedagogical Inquiry into Foucault's "Limit-Experience"

    ERIC Educational Resources Information Center

    Thompson, Christiane

    2010-01-01

    This paper is concerned with the educational-philosophical implications of Michel Foucault's work: It poses the question whether Michel Foucault's remarks surrounding "limit-experience" can be placed in an educational context and provide an alternative view regarding the relationship that we maintain to ourselves. As a first step, the significance…

  3. Being Careful with PASCO's Kinetic Friction Experiment: Uncovering Pre-Sliding Displacement?

    ERIC Educational Resources Information Center

    Lawlor, T. M.

    2008-01-01

    The widely used PASCO laboratory equipment is an excellent way to introduce students to many topics in physics. In one case, PASCO's equipment may be too good! Various experiments exist for calculating the kinetic coefficient of friction by measuring the acceleration of a sliding object under some constant force. With ever more accurate equipment,…

  4. Visualization of micro-scale phase displacement processes in retention and outflow experiments: Non-uniqueness of unsaturated flow properties

    SciTech Connect

    MORTENSEN,ANNETTE P.; GLASS JR.,ROBERT J.; HOLLENBECK,KARL; JENSEN,KARSTEN H.

    2000-03-09

    Methods to determine unsaturated hydraulic properties can exhibit random and non-unique behavior. The authors assess the causes for these behaviors by visualizing micro-scale phase displacement processes during equilibrium retention and transient outflow experiments. They observe that the drainage process is composed of a fast fingering followed by a slower backfilling. The influence of each these processes is controlled by the size and the speed of the applied boundary step, the initial saturation and its structure and by small-scale heterogeneities. Because the mixture of these micro-scale processes yields macro-scale effective behavior, measured unsaturated flow properties are also a function of these controls. These results suggest limitations on the current definitions and uniqueness of unsaturated hydraulic properties.

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

    NASA Astrophysics Data System (ADS)

    Fernández-Sanjurjo, M. J.; Alvarez-Rodríguez, E.; Núñez-Delgado, A.; Fernández-Marcos, M. L.; Romar-Gasalla, A.

    2014-07-01

    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.

  6. In situ vertical circulation column: Containment system for small-scale DNAPL field experiments

    SciTech Connect

    Sorel, D.; Cherry, J.A.; Lesage, S.

    1998-12-31

    The in situ vertical circulation column (ISVCC) is a cylindrical containment system consisting of an instrumented steel cylinder used for experimental ground water studies in sandy aquifers. Vertical flow is imposed inside the ISVCC. Although vertical wells are an option, the ISVCC installed in the Borden Aquifer is instrumented with horizontal wells and monitoring ports to avoid creating vertical preferential flow paths. Pure phase DNAPL (tetrachloroethene and 1,1,1-trichloroethane) was slowly pumped into two ports in the center of the column. Following this DNAPL injection, an aqueous solution of vitamin B{sub 12} and reduced titanium was circulated through the column to promote degradation of the solvents. Processes observed in the ISVCC included DNAPL distribution, dissolution, and degradation, and geochemical evolution of the aquifer. The ISVCC provides a convenient means for testing in situ technologies in the experimental stage or for selection of proven technologies to find the most effective at a specific site. It is inexpensive, easy to install, and maximizes control over flow distribution in a heterogeneous aquifer. Its application will be restricted where low hydraulic conductivity beds are present in the aquifer.

  7. Mobility, Deposition and Remobilization of pre-Synthesis Stabilized Nano-scale Zero Valent Iron in Long Column Experiments

    NASA Astrophysics Data System (ADS)

    de Boer, C. V.; O'Carroll, D. M.; Sleep, B.

    2014-12-01

    Reactive zero-valent iron is currently being used for remediation of contaminated groundwater. Permeable reactive barriers are the current state-of-the-practice method for using zero-valent iron. Instead of an excavated trench filled with granular zero-valent iron, a relatively new and promising method is the injection of a nano-scale zero-valent iron colloid suspension (nZVI) into the subsurface using injection wells. One goal of nZVI injection can be to deposit zero valent iron in the aquifer and form a reactive permeable zone which is no longer bound to limited depths and plume treatment, but can also be used directly at the source. It is very important to have a good understanding of the transport behavior of nZVI during injection as well as the fate of nZVI after injection due to changes in the flow regime or water chemistry changes. So far transport was mainly tested using commercially available nZVI, however these studies suggest that further work is required as commercial nZVI was prone to aggregation, resulting in low physical stability of the suspension and very short travel distances in the subsurface. In the presented work, nZVI is stabilized during synthesis to significantly increase the physical suspension stability. To improve our understanding of nZVI transport, the feasibility for injection into various porous media materials and controlled deposition, a suite of column experiments are conducted. The column experiments are performed using a long 1.5m column and a novel nZVI measuring technique. The measuring technique was developed to non-destructively determine the concentration of nano-scale iron during the injection. It records the magnetic susceptibility, which makes it possible to get transient nZVI retention profiles along the column. These transient nZVI retention profiles of long columns provide unique insights in the transport behavior of nZVI which cannot be obtained using short columns or effluent breakthrough curves.

  8. Cr(VI) removal from aqueous systems using pyrite as the reducing agent: Batch, spectroscopic and column experiments

    NASA Astrophysics Data System (ADS)

    Kantar, Cetin; Ari, Cihan; Keskin, Selda; Dogaroglu, Zeynep Gorkem; Karadeniz, Aykut; Alten, Akin

    2015-03-01

    Laboratory batch and column experiments, in conjunction with geochemical calculations and spectroscopic analysis, were performed to better understand reaction mechanisms and kinetics associated with Cr(VI) removal from aqueous systems using pyrite as the reactive material under both static and dynamic flow conditions similar to those observed in in situ permeable reactive barriers (PRBs). The X-ray photoelectron spectroscopy (XPS) and geochemical calculations suggest that the Cr(VI) removal by pyrite occurred due to the reduction of Cr(VI) to Cr(III), coupled with the oxidation of Fe(II) to Fe(III) and S22 - to SO42 - at the pyrite surface. Zeta potential measurements indicate that although the pyrite surface was negatively charged under a wide pH range in the absence of Cr(VI), it behaved more like a "metal oxide" surface with the surface potential shifting from positive to negative values at pH values > pH 6 in the presence of Cr(VI). Batch experiments show that increasing solution pH led to a significant decrease in Cr(VI) removal. The decrease in Cr(VI) removal at high Cr(VI) concentrations and pH values can be explained through the precipitation of sparingly soluble Cr(OH)3(s), Fe(OH)3(s) and Fe(III)-Cr(III) (oxy) hydroxides onto pyrite surface which may, then, lead to surface passivation for further Cr(VI) reduction. Batch results also suggest that the reaction kinetics follow a first order model with rate constants decreasing with increasing solution pH, indicating proton consumption during Cr(VI) reduction by pyrite. Column experiments indicate that nearly 100% of total Fe in the column effluent was in the form of Fe(II) species with a [SO42 -]/[Fe2 +] stoichiometric ratio of 2.04, indicating that the reduction of Cr(VI) by pyrite produced about 2 mol of sulfate per mole of Fe (II) release under excess surface sites relative to Cr(VI) concentration. Column experiments provide further evidence on the accumulation of oxidation products which consequently led

  9. Cr(VI) removal from aqueous systems using pyrite as the reducing agent: batch, spectroscopic and column experiments.

    PubMed

    Kantar, Cetin; Ari, Cihan; Keskin, Selda; Dogaroglu, Zeynep Gorkem; Karadeniz, Aykut; Alten, Akin

    2015-03-01

    Laboratory batch and column experiments, in conjunction with geochemical calculations and spectroscopic analysis, were performed to better understand reaction mechanisms and kinetics associated with Cr(VI) removal from aqueous systems using pyrite as the reactive material under both static and dynamic flow conditions similar to those observed in in situ permeable reactive barriers (PRBs). The X-ray photoelectron spectroscopy (XPS) and geochemical calculations suggest that the Cr(VI) removal by pyrite occurred due to the reduction of Cr(VI) to Cr(III), coupled with the oxidation of Fe(II) to Fe(III) and S2(2-) to SO4(2-) at the pyrite surface. Zeta potential measurements indicate that although the pyrite surface was negatively charged under a wide pH range in the absence of Cr(VI), it behaved more like a "metal oxide" surface with the surface potential shifting from positive to negative values at pH values >pH 6 in the presence of Cr(VI). Batch experiments show that increasing solution pH led to a significant decrease in Cr(VI) removal. The decrease in Cr(VI) removal at high Cr(VI) concentrations and pH values can be explained through the precipitation of sparingly soluble Cr(OH)(3(s)), Fe(OH)(3(s)) and Fe(III)-Cr(III) (oxy) hydroxides onto pyrite surface which may, then, lead to surface passivation for further Cr(VI) reduction. Batch results also suggest that the reaction kinetics follow a first order model with rate constants decreasing with increasing solution pH, indicating proton consumption during Cr(VI) reduction by pyrite. Column experiments indicate that nearly 100% of total Fe in the column effluent was in the form of Fe(II) species with a [SO4(2-)]/[Fe(2+)] stoichiometric ratio of 2.04, indicating that the reduction of Cr(VI) by pyrite produced about 2 mol of sulfate per mole of Fe (II) release under excess surface sites relative to Cr(VI) concentration. Column experiments provide further evidence on the accumulation of oxidation products which

  10. Biodegradation of the surfactant linear alkylbenzenesulfonate in sewage- contaminated groundwater: A comparison of column experiments and field tracer tests

    USGS Publications Warehouse

    Krueger, C.J.; Radakovich, K.M.; Sawyer, T.E.; Barber, L.B.; Smith, R.L.; Field, J.A.

    1998-01-01

    Transport and biodegradation of linear alkylbenzenesulfonate (LAS) in sewage-contaminated groundwater were investigated for a range of dissolved oxygen concentrations. Both laboratory column and an 80-day continuous injection tracer test field experiments were conducted. The rates of LAS biodegradation increased with increasing dissolved oxygen concentrations and indicated the preferential biodegradation of the longer alkyl chain LAS homologues (i.e., C12 and C13) and external isomers (i.e., 2-and 3- phenyl). However, for similar dissolved oxygen concentrations, mass removal rates for LAS generally were 2-3 times greater in laboratory column experiments than in the field tracer test. Under low oxygen conditions (<1 mg/L) only a fraction of the LAS mixture biodegraded in both laboratory and field experiments. Biodegradation rate constants for the continuous injection field test (0.002-0.08 day-1) were comparable to those estimated for a 3-h injection (pulsed) tracer test conducted under similar biogeochemical conditions, indicating that increasing the exposure time of aquifer sediments to LAS did not increase biodegradation rates.Transport and biodegradation of linear alkylbenzenesulfonate (LAS) in sewage-contaminated groundwater were investigated for a range of dissolved oxygen concentrations. Both laboratory column and an 80-day continuous injection tracer test field experiments were conducted. The rates of LAS biodegradation increased with increasing dissolved oxygen concentrations and indicated the preferential biodegradation of the longer alkyl chain LAS homologues (i.e., C12 and C13) and external isomers (i.e., 2- and 3-phenyl). However, for similar dissolved oxygen concentrations, mass removal rates for LAS generally were 2-3 times greater in laboratory column experiments than in the field tracer test. Under low oxygen conditions (<1 mg/L) only a fraction of the LAS mixture biodegraded in both laboratory and field experiments. Biodegradation rate constants

  11. Description and field performance of the Walker Branch throughfall displacement experiment: 1993--1996

    SciTech Connect

    Hanson, P.J.; Todd, D.E.; Huston, M.A.; Joslin, J.D.; Croker, J.L.; Auge, R.M.

    1998-04-01

    The authors are conducting a large-scale manipulative field experiment in an upland oak forest on the Walker Branch Watershed in eastern Tennessee to identify important ecosystem responses that might result from future precipitation changes. The manipulation of soil water content is being implemented by a gravity-driven transfer of throughfall from one 6400-m{sup 2} treatment plot to another. Throughfall is intercepted in {approx}1850 subcanopy troughs suspended above the forest floor of the dry plot and transferred by gravity flow across an ambient plot for subsequent distribution onto the wet treatment plot. Soil water content is being monitored at two depths with time domain reflectometers at 310 sampling locations across the site. The experimental system is able to produce statistically significant differences in soil water content in years having both dry and wet conditions. Maximum soil water content differentials between wet and dry plots in the 0- to 0.35-m horizon were 8 to 10% during summers with abundant precipitation and 3 to 5% during drought periods. Treatment impacts on soil water potential were restricted to the surface soil layer. Comparisons of pre- and post-installation soil and litter temperature measurements showed the ability of the experimental design to produce changes in soil water content and water potential without creating large artifacts in the forest understory environment.

  12. Column CO2 Measurements with Intensity-Modulated Continuous-Wave Lidar System During the ASCENDS 2014 Summer Field Experiment

    NASA Astrophysics Data System (ADS)

    Meadows, B.; Nehrir, A. R.; Lin, B.; Harrison, F. W.; Dobler, J. T.; Kooi, S. A.; Campbell, J. F.; Obland, M. D.; Browell, E. V.; Yang, M. M.

    2014-12-01

    This paper presents an overview of the ASCENDS 2014 flight campaign results of an intensity-modulated continuous-wave (IM-CW) lidar system operating at 1.57 µm for measurements of column CO2 over a wide variety of geographic regions. The 2007 National Research Council's Decadal Survey of Earth Science and Applications from Space recommended Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) as a mid-term, Tier II, space mission to address global sources, sinks, and transport of atmospheric CO2. As part of the development of a capability for the NASA ASCENDS mission, NASA Langley Research Center (LaRC) and Exelis, Inc. have been collaborating to develop, demonstrate and mature the IM-CW lidar approach for measuring atmospheric column CO2 mixing ratios from a space platform using the integrated path differential absorption (IPDA) lidar technique with preferential weighting of the CO2 measurements to the mid to lower troposphere. The Multi-Functional Fiber Laser Lidar (MFLL), a system developed as a technology demonstrator for the ASCENDS mission, has been used to demonstrate high precision column CO2 retrievals from various aircraft platforms. The MFLL operates using a novel IM-CW IPDA approach to make simultaneous CO2 and O2 column measurements in the 1.57-micron and 1.26-micron spectral regions, respectively, to derive the column-average CO2 dry-air mixing ratios. Measurements from the 2014 summer field experiment focused on advancing CO2 & O2 measurement technologies under day and night conditions in realistic environments, assessing CO2 emissions over large metropolitan areas, observing and evaluating CO2 drawdown and diurnal trends over large agricultural regions, obtaining reflectance data and CO2 & O2 measurements over rough ocean surfaces with high surface wind speeds (~10 m/s), and carrying out CO2 & O2 intercomparisons with OCO-2 and GOSAT over the western United States. Initial results from MFLL for the aforementioned flight campaign

  13. Do lab-derived distribution coefficient values of pesticides match distribution coefficient values determined from column and field-scale experiments? A critical analysis of relevant literature.

    PubMed

    Vereecken, H; Vanderborght, J; Kasteel, R; Spiteller, M; Schäffer, A; Close, M

    2011-01-01

    In this study, we analyzed sorption parameters for pesticides that were derived from batch and column or batch and field experiments. The batch experiments analyzed in this study were run with the same pesticide and soil as in the column and field experiments. We analyzed the relationship between the pore water velocity of the column and field experiments, solute residence times, and sorption parameters, such as the organic carbon normalized distribution coefficient ( ) and the mass exchange coefficient in kinetic models, as well as the predictability of sorption parameters from basic soil properties. The batch/column analysis included 38 studies with a total of 139 observations. The batch/field analysis included five studies, resulting in a dataset of 24 observations. For the batch/column data, power law relationships between pore water velocity, residence time, and sorption constants were derived. The unexplained variability in these equations was reduced, taking into account the saturation status and the packing status (disturbed-undisturbed) of the soil sample. A new regression equation was derived that allows estimating the values derived from column experiments using organic matter and bulk density with an value of 0.56. Regression analysis of the batch/column data showed that the relationship between batch- and column-derived values depends on the saturation status and packing of the soil column. Analysis of the batch/field data showed that as the batch-derived value becomes larger, field-derived values tend to be lower than the corresponding batch-derived values, and vice versa. The present dataset also showed that the variability in the ratio of batch- to column-derived value increases with increasing pore water velocity, with a maximum value approaching 3.5. PMID:21546674

  14. Evaluating the long-term performance of low-cost adsorbents using small-scale adsorption column experiments.

    PubMed

    Callery, O; Healy, M G; Rognard, F; Barthelemy, L; Brennan, R B

    2016-09-15

    This study investigated a novel method of predicting the long-term phosphorus removal performance of large-scale adsorption filters, using data derived from short-term, small-scale column experiments. The filter media investigated were low-cost adsorbents such as aluminum sulfate drinking water treatment residual, ferric sulfate drinking water treatment residual, and fine and coarse crushed concretes. Small-bore adsorption columns were loaded with synthetic wastewater, and treated column effluent volume was plotted against the mass of phosphorus adsorbed per unit mass of filter media. It was observed that the curve described by the data strongly resembled that of a standard adsorption isotherm created from batch adsorption data. Consequently, it was hypothesized that an equation following the form of the Freundlich isotherm would describe the relationship between filter loading and media saturation. Moreover, the relationship between filter loading and effluent concentration could also be derived from this equation. The proposed model was demonstrated to accurately predict the performance of large-scale adsorption filters over a period of up to three months with a very high degree of accuracy. Furthermore, the coefficients necessary to produce said model could be determined from just 24 h of small-scale experimental data. PMID:27295617

  15. Chromium Isotopic Fractionation During Biogeochemical Cr (IV) Reduction in Hanford Sediment Column Experiments with Native Aquifer Microbial Communities

    NASA Astrophysics Data System (ADS)

    Qin, L.; Christensen, J. N.; Brown, S. T.; Yang, L.; Conrad, M. E.; Sonnenthal, E. L.; Beller, H. R.

    2010-12-01

    Hexavalent Chromium contamination in groundwater within the DOE complex, including the Hanford 100D and 100H sites has been a long-standing issue. It has been established that certain bacteria (including denitrifying and sulfate-reducing bacteria) harbor enzymes that catalyze Cr(VI) reduction to relatively nontoxic Cr(III). Microbial reduction of Cr(VI) also occurs indirectly by products of microbial respiration, such as sulfide and Fe(II). Chromium isotopes can be fractionated during Cr(VI) reduction and provides a potential basis for characterizing and discriminating between different microbial metabolic and geochemical pathways associated with Cr(VI) reductive immobilization. Addition of electron donor to contaminated groundwater systems to create conditions favorable for reductive metal immobilization has become a widely utilized remediation practice. We conducted a series of small-scale column experiments with homogenized material from the Hanford 100H aquifer to examine the effects of differing electron acceptors on local microbial communities. All columns have a continuous inflow of solutions with constant concentrations of Cr(VI), lactate (electron donor), and the appropriate electron acceptor (e.g. nitrate or sulfate). The Cr isotopic composition in the effluent was measured using a 50-54 double-spike technique and a Triton TIMS. Cr concentration measurements showed that the greatest Cr(VI) reduction occurred in the sulfate columns. Our preliminary Cr isotopic data show that under these conditions the delta 53Cr value increased from close to 0 to 4 per mil while the Cr concentration decreased from 260 ppb to 30 ppb in the effluent. This yields an apparent fractionation factor of 0.9979 (2.1 per mil). A decrease in Cr concentration from 260 ppb to 190 ppb in a nitrate-reducing column was accompanied by an increase of 1 per mil in delta 53Cr. Further Cr isotopic data will be presented and the effects of differing flow rates and electron acceptors will be

  16. Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments

    SciTech Connect

    Brubaker, Tonya M; Stewart, Brian W; Capo, Rosemary C; Schroeder, Karl T; Chapman, Elizabeth C; Spivak-Birndorf, Lev J; Vesper, Dorothy J; Cardone, Carol R; Rohar, Paul C

    2013-05-01

    The major element and Sr isotope systematics and geochemistry of coal fly ash and its interactions with environmental waters were investigated using laboratory flow-through column leaching experiments (sodium carbonate, acetic acid, nitric acid) and sequential batch leaching experiments (water, acetic acid, hydrochloric acid). Column leaching of Class F fly ash samples shows rapid release of most major elements early in the leaching procedure, suggesting an association of these elements with soluble and surface bound phases. Delayed release of certain elements (e.g., Al, Fe, Si) signals gradual dissolution of more resistant silicate or glass phases as leaching continues. Strontium isotope results from both column and batch leaching experiments show a marked increase in {sup 87}Sr/{sup 86}Sr ratio with continued leaching, yielding a total range of values from 0.7107 to 0.7138. For comparison, the isotopic composition of fluid output from a fly ash impoundment in West Virginia falls in a narrow range around 0.7124. The experimental data suggest the presence of a more resistant, highly radiogenic silicate phase that survives the combustion process and is leached after the more soluble minerals are removed. Strontium isotopic homogenization of minerals in coal does not always occur during the combustion process, despite the high temperatures encountered in the boiler. Early-released Sr tends to be isotopically uniform; thus the Sr isotopic composition of fly ash could be distinguishable from other sources and is a useful tool for quantifying the possible contribution of fly ash leaching to the total dissolved load in natural surface and ground waters.

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

    NASA Astrophysics Data System (ADS)

    Fernández-Sanjurjo, M. J.; Alvarez-Rodríguez, E.; Núñez-Delgado, A.; Fernández-Marcos, M. L.; Romar-Gasalla, A.

    2014-12-01

    The objective of this work was to study nutrients release from two compressed nitrogen-potassium-phosphorous (NPK) fertilizers. In the Lourizán Forest Center, tablet-type controlled-release fertilizers (CRF) were prepared by compressing various mixtures of fertilizers without covers or binders. We used soil columns (50 cm long and 7.3 cm inner diameter) that were filled with soil from the surface layer (0-20 cm) of an A horizon corresponding to a Cambic Umbrisol. Tablets of two slow-release NPK fertilizers (11-18-11 or 8-8-16) were placed into the soil (within the first 3 cm), and then water was percolated through the columns in a saturated regime for 80 days. Percolates were analyzed for N, P, K+, Ca2+ and Mg2+. These elements were also determined in soil and fertilizer tablets at the end of the trials. Nutrient concentrations were high in the first leachates and reached a steady state when 1426 mm of water had been percolated, which is equivalent to approximately 1.5 years of rainfall in this geographic area. In the whole trial, both tablets lost more than 80% of their initial N, P and K contents. However, K+, Ca2+ and Mg2+ were the most leached, whereas N and P were lost in leachates to a lesser extent. Nutrient release was slower from the tablet with a composition of 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, with a significant increase of pH, available Ca2+, Mg2+, K+, P and effective cation exchange capacity (eCEC) in the fertilized columns, as well as a significant decrease in exchangeable Al3+, reaching values < 0.08 cmol (+) kg-1.

  18. Simulation of Observed PCBs and Pesticides in the Water Column during the North Atlantic Bloom Experiment.

    PubMed

    Zhang, Lin; Thibodeaux, Louis; Jones, Lee; Lohmann, Rainer

    2015-12-01

    The dynamics of persistent organic pollutants in the oceans are not well constrained, in particular during a bloom formation and collapse. Polychlorinated biphenyls (PCBs) and some pesticides were measured in air, water, and zooplankton tracking the North Atlantic Bloom in May 2008. Lower weight PCBs were entering the water column from the atmosphere during the main bloom period but reached equilibrium after the bloom collapsed. The PCBs in the lipids of zooplankton Calanus were in equilibrium with those in the dissolved phase. A Lagrangian box model was developed to simulate the dissolved phase PCBs and pesticides by including the following processes: air-water exchange, reversible sorption to POC, changes in mixed layer depth, removal by sinking particles, and degradation. Results suggest that sorption to (sinking) POC was the dominant removal process for hydrophobic pollutants from seawater. Statistical test suggested simulated results were not significantly different from observed values for hydrophobic pollutants (p,p'-DDE).

  19. Effective rates of heavy metal release from alkaline wastes — Quantified by column outflow experiments and inverse simulations

    NASA Astrophysics Data System (ADS)

    Wehrer, Markus; Totsche, Kai Uwe

    2008-10-01

    Column outflow experiments operated at steady state flow conditions do not allow the identification of rate limited release processes. This requires an alternative experimental methodology. In this study, the aim was to apply such a methodology in order to identify and quantify effective release rates of heavy metals from granular wastes. Column experiments were conducted with demolition waste and municipal waste incineration (MSWI) bottom ash using different flow velocities and multiple flow interruptions. The effluent was analyzed for heavy metals, DOC, electrical conductivity and pH. The breakthrough-curves were inversely modeled with a numerical code based on the advection-dispersion equation with first order mass-transfer and nonlinear interaction terms. Chromium, Copper, Nickel and Arsenic are usually released under non-equilibrium conditions. DOC might play a role as carrier for those trace metals. By inverse simulations, generally good model fits are derived. Although some parameters are correlated and some model deficiencies can be revealed, we are able to deduce physically reasonable release-mass-transfer time scales. Applying forward simulations, the parameter space with equifinal parameter sets was delineated. The results demonstrate that the presented experimental design is capable of identifying and quantifying non-equilibrium conditions. They show also that the possibility of rate limited release must not be neglected in release and transport studies involving inorganic contaminants.

  20. The removal of arsenate from water using iron-modified diatomite (D-Fe): isotherm and column experiments.

    PubMed

    Pantoja, M L; Jones, H; Garelick, H; Mohamedbakr, H G; Burkitbayev, M

    2014-01-01

    Iron hydroxide supported onto porous diatomite (D-Fe) is a low-cost material with potential to remove arsenic from contaminated water due to its affinity for the arsenate ion. This affinity was tested under varying conditions of pH, contact time, iron content in D-Fe and the presence of competitive ions, silicate and phosphate. Batch and column experiments were conducted to derive adsorption isotherms and breakthrough behaviours (50 μg L(-1)) for an initial concentration of 1,000 μg L(-1). Maximum capacity at pH 4 and 17% iron was 18.12-40.82 mg of arsenic/g of D-Fe and at pH 4 and 10% iron was 18.48-29.07 mg of arsenic/g of D-Fe. Adsorption decreased in the presence of phosphate and silicate ions. The difference in column adsorption behaviour between 10% and 17% iron was very pronounced, outweighing the impact of all other measured parameters. There was insufficient evidence of a correlation between iron content and arsenic content in isotherm experiments, suggesting that ion exchange is a negligible process occurring in arsenate adsorption using D-Fe nor is there co-precipitation of arsenate by rising iron content of the solute above saturation.

  1. Estimating the dual-enzyme kinetic parameters for Cr (VI) reduction by Shewanella oneidensis MR-1 from soil column experiments.

    PubMed

    Hossain, Md Akram; Alam, Mahbub; Yonge, David R

    2005-09-01

    Hexavalent chromium (Cr (VI)) contamination of soil and groundwater is considered a major environmental concern. Bioreduction of Cr (VI) to trivalent chromium (Cr (III)) can be considered an effective technology in remediating Cr (VI) contaminated sites. Among the Cr (VI) reducing bacteria, Shewanella oneidensis MR-1 (MR-1) is relatively effective. Reduction of Cr (VI) by MR-1 is defined by the dual-enzyme kinetic model. The feasibility of bioreduction of Cr (VI) is usually evaluated by performing batch experiments which may not accurately represent the subsurface environment. The objective of this paper is to present a rational approach to determine the dual-enzyme reaction kinetics of Cr (VI) reduction by MR-1 from continuous flow soil column experiments which more accurately simulate the subsurface environment. Kinetic parameters obtained from soil column data were found to be much smaller than that obtained from batch data. The stable enzyme induced reaction rate was found to be 127th and the average deactivating enzyme induced reaction rate was 117th of the corresponding values obtained from batch reactor data as reported in literature.

  2. Predicting the holistic force-displacement relation of the periodontal ligament: in-vitro experiments and finite element analysis

    PubMed Central

    2014-01-01

    Background The biomechanical property of the periodontal ligament (PDL) is important in orthodontics and prosthodontics. The objective of this study was to evaluate the feasibility of measuring the biomechanical behavior of the periodontal ligament using micro-computed tomography (micro-CT). Methods A custom-made apparatus measured the force and displacement of a porcine PDL specimen within the micro-CT environment. Synchronized computed tomography (CT) images were used to obtain the deformation and displacement of the entire specimen and to reconstruct the three-dimensional mesh model. To match the experimental results, finite element analysis was then applied to simulate the biomechanical response of the PDL. The mechanical model of the PDL was assumed as the hyperelastic material in this study. Results The volume variations of the tooth and the alveolar bone were less than 1%, which implies that tooth displacement was caused mostly by displacement of the PDL. Only translational displacement was observed with each load step because the transformation matrix acquired from the CT image registration was identical. The force-displacement curve revealed the nonlinear behavior of the PDL. There was a high correlation between the experimental displacement results and the simulation displacement results. The numerical results (based on the assumption that the PDL is the hyperelastic material) showed good agreement with the experimental results. Conclusions Nondestructive measurements by micro-CT obtained the biomechanical behavior of the PDL. Using the hyperelastic characteristic as the constitutive model can properly predict the force-displacement relation of the PDL after loading. This study provided a feasible approach for measuring the biomechanical behavior of the PDL for further dental application. PMID:25077405

  3. Amplification and attenuation of tetracycline resistance in soil bacteria: aquifer column experiments.

    PubMed

    Rysz, Michal; Alvarez, Pedro J J

    2004-10-01

    A growing inefficacy of antimicrobial agents to treat infectious diseases has stimulated research on the development of antibiotic resistance in bacteria in the environment. Sustained exposure of soil microorganisms to tetracycline (TC) in flow-through columns (50mg/L influent) significantly decreased the effluent concentration of total heterotrophs and selected for TC-resistant (Tet(r)) soil bacteria. This suggests that TC released to the environment from animal farms may contribute to the development and amplification of TC resistance, with soil bacteria serving as reservoirs for antibiotic resistance continuance. Burkholderia cepacia, with genetic determinants for efflux pumps that facilitate TC excretion, was the only bacterium that grew on TC-amended R2A plates. Following 300 days of exposure, TC was removed from the influent to study the recovery pattern of the microbial community. The percentage of Tet(r) hererotrophs decreased from 25% to close to the control level of 1% within 1 month of discontinuing TC exposure. This was due both to a significant rebound in the total heterotrophic population and to a significant decrease in the concentration of Tet(r) bacteria. Thus, discontinuing TC exposure or curtailing its use should enhance natural attenuation mechanisms that mitigate the spread of resistance vectors. PMID:15350422

  4. Modeling long term Enhanced in situ Biodenitrification and induced heterogeneity in column experiments under different feeding strategies

    NASA Astrophysics Data System (ADS)

    Rodríguez-Escales, Paula; Folch, Albert; van Breukelen, Boris M.; Vidal-Gavilan, Georgina; Sanchez-Vila, Xavier

    2016-07-01

    Enhanced In situ Biodenitrification (EIB) is a capable technology for nitrate removal in subsurface water resources. Optimizing the performance of EIB implies devising an appropriate feeding strategy involving two design parameters: carbon injection frequency and C:N ratio of the organic substrate nitrate mixture. Here we model data on the spatial and temporal evolution of nitrate (up to 1.2 mM), organic carbon (ethanol), and biomass measured during a 342 day-long laboratory column experiment (published in Vidal-Gavilan et al., 2014). Effective porosity was 3% lower and dispersivity had a sevenfold increase at the end of the experiment as compared to those at the beginning. These changes in transport parameters were attributed to the development of a biofilm. A reactive transport model explored the EIB performance in response to daily and weekly feeding strategies. The latter resulted in significant temporal variation in nitrate and ethanol concentrations at the outlet of the column. On the contrary, a daily feeding strategy resulted in quite stable and low concentrations at the outlet and complete denitrification. At intermediate times (six months of experiment), it was possible to reduce the carbon load and consequently the C:N ratio (from 2.5 to 1), partly because biomass decay acted as endogenous carbon to respiration, keeping the denitrification rates, and partly due to the induced dispersivity caused by the well-developed biofilm, resulting in enhancement of mixing between the ethanol and nitrate and the corresponding improvement of denitrification rates. The inclusion of a dual-domain model improved the fit at the last days of the experiment as well as in the tracer test performed at day 342, demonstrating a potential transition to anomalous transport that may be caused by the development of biofilm. This modeling work is a step forward to devising optimal injection conditions and substrate rates to enhance EIB performance by minimizing the overall supply of

  5. Transport of sulfadiazine in soil columnsExperiments and modelling approaches

    NASA Astrophysics Data System (ADS)

    Wehrhan, Anne; Kasteel, Roy; Simunek, Jirka; Groeneweg, Joost; Vereecken, Harry

    2007-01-01

    Antibiotics, such as sulfadiazine, reach agricultural soils directly through manure of grazing livestock or indirectly through the spreading of manure or sewage sludge on the field. Knowledge about the fate of antibiotics in soils is crucial for assessing the environmental risk of these compounds, including possible transport to the groundwater. Transport of 14C-labelled sulfadiazine was investigated in disturbed soil columns at a constant flow rate of 0.26 cm h - 1 near saturation. Sulfadiazine was applied in different concentrations for either a short or a long pulse duration. Breakthrough curves of sulfadiazine and the non-reactive tracer chloride were measured. At the end of the leaching period the soil concentration profiles were determined. The peak maxima of the breakthrough curves were delayed by a factor of 2 to 5 compared to chloride and the decreasing limbs are characterized by an extended tailing. However, the maximum relative concentrations differed as well as the eluted mass fractions, ranging from 18 to 83% after 500 h of leaching. To identify relevant sorption processes, breakthrough curves of sulfadiazine were fitted with a convective-dispersive transport model, considering different sorption concepts with one, two and three sorption sites. Breakthrough curves can be fitted best with a three-site sorption model, which includes two reversible kinetic and one irreversible sorption site. However, the simulated soil concentration profiles did not match the observations for all of the used models. Despite this incomplete process description, the obtained results have implications for the transport behavior of sulfadiazine in the field. Its leaching may be enhanced if it is frequently applied at higher concentrations.

  6. Discrete particle simulations and experiments on the collapse of wet granular columns

    NASA Astrophysics Data System (ADS)

    Gabrieli, Fabio; Artoni, Riccardo; Santomaso, Andrea; Cola, Simonetta

    2013-10-01

    Small quantities of liquid in a granular material control the flow dynamics as well as the triggering and jamming phases. In order to study this problem, some experimental collapse tests conducted in a rectangular box were reproduced with a 1:1 scale numerical model using the Discrete Element Method. In simulations the effect of the capillary bridges has been investigated implementing a mid-range attractive force between particles based on the minimum energy approach. Also a bonding-debonding mechanism was incorporated in the algorithm and the volume of each sessile drop on the particle surface was considered during its motion. The influence of some variables was investigated with respect to the final slope profiles and the runout lengths: the initial liquid content, the particle size, the solid density, the liquid surface tension, and the liquid-solid contact angle. Also the crucial effect of the confinement walls on the collapse phenomenon was investigated: wet particles adhere to the lateral walls providing a higher flow resistance in comparison to the same material in dry conditions. It was observed that particles with largest path-lengths are localized near the movable wall at a middle-height of the initial column sample. Other particles at the surface moves in a rigid way especially if they were wet and with a low solid density. The "fidelity" of each particle with respect to the nearest neighbours was evaluated allowing to recognize the emergence of clusters of particles and rigid parts, to extract the failure surface and to localize where debonding mechanisms concentrate in the wet case.

  7. Use of caustic magnesia to remove cadmium, nickel, and cobalt from water in passive treatment systems: column experiments

    SciTech Connect

    Tobias Stefan Roetting; Jordi Cama; Carlos Ayora; Jose-Luis Cortina; Joan De Pablo

    2006-10-15

    In the present study caustic magnesia obtained from calcination of magnesium carbonate was tested in column experiments as an alternative material for passive remediation systems to remove divalent metals. Caustic magnesia reacts with water to form magnesium hydroxide, which dissolves increasing the pH to values higher than 8.5. At these pH values, cadmium is precipitated as otavite and to a minor amount as a hydroxide. Cobalt and nickel are precipitated as hydroxides which form isostructural solids with brucite. Thus, metal concentrations as high as 75 mg/L in the inflowing water are depleted to values below 10 {mu}g/L. Magnesia dissolution is sufficiently fast to treat flows as high as 0.5 m{sup 3}/m{sup 2} per day. For reactive grain size of 2-4 mm, the column efficiency ends due to coating of the grains by precipitates, especially when iron and aluminum are present in the solution. 23 refs., 7 figs., 1 tab.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  9. Drought reduced monoterpene emissions from Quercus ilex trees: results from a throughfall displacement experiment within a forest ecosystem

    NASA Astrophysics Data System (ADS)

    Lavoir, A. V.; Staudt, M.; Schnitzler, J. P.; Landais, D.; Massol, F.; Rocheteau, A.; Rodriguez, R.; Zimmer, I.; Rambal, S.

    2009-01-01

    The effects of water limitations on the emission of biogenic volatile organic compounds are not well understood. Experimental approaches studying drought effects in natural conditions are still missing. To address this question, a throughfall displacement experiment was set up in a natural forest of Quercus ilex, an evergreen Mediterranean oak emitting monoterpenes. Mature trees were exposed in 2005 and 2006 either to an additional drought, to irrigation or to natural drought (untreated control). In both years, absolute monoterpene emission rates as well as the respective standard factors of the trees exposed to normal and additional drought strongly declined during the drought periods. Monoterpene emissions were lower in year 2006 than in year 2005 (factor 2) due to a more pronounced summer drought period in this respective year. We observed a significant difference between the irrigation and additional drought or control treatment: irrigated trees emitted 82% more monoterpenes during the drought period 2006 than the trees of the other treatments. However, no significant effect on monoterpene emission was observed between normal and additional drought treatments, despite a significant effect on leaf water potential and photochemical efficiency. During the development of drought, monoterpene emissions responded exponentially rather than linearly to decreasing leaf water potential. Emissions rapidly declined when the water potential dropped below -2 MPa and photosynthesis was persistently inhibited. Monoterpene synthase activities measured in vitro showed no clear reduction during the same period. From our results we conclude that drought significantly reduces monoterpene fluxes of Mediterranean evergreen forest into the atmosphere due to a sustained inhibition of photosynthetic carbon assimilation.

  10. Drought reduced monoterpene emissions from the evergreen Mediterranean oak Quercus ilex: results from a throughfall displacement experiment

    NASA Astrophysics Data System (ADS)

    Lavoir, A.-V.; Staudt, M.; Schnitzler, J. P.; Landais, D.; Massol, F.; Rocheteau, A.; Rodriguez, R.; Zimmer, I.; Rambal, S.

    2009-07-01

    The effects of water limitations on the emission of biogenic volatile organic compounds are not well understood. Experimental approaches studying drought effects in natural conditions are still missing. To address this question, a throughfall displacement experiment was set up in a natural forest of Quercus ilex, an evergreen Mediterranean oak emitting monoterpenes. Mature trees were exposed in 2005 and 2006 either to an additional drought, to irrigation or to natural drought (untreated control). In both years, absolute monoterpene emission rates as well as the respective standard factors of the trees exposed to normal and additional drought strongly declined during the drought periods. Monoterpene emissions were lower in year 2006 than in year 2005 (factor 2) due to a more pronounced summer drought period in this respective year. We observed a significant difference between the irrigation and additional drought or control treatment: irrigated trees emitted 82% more monoterpenes during the drought period 2006 than the trees of the other treatments. However, no significant effect on monoterpene emission was observed between normal and additional drought treatments, despite a significant effect on leaf water potential and photochemical efficiency. During the development of drought, monoterpene emissions responded exponentially rather than linearly to decreasing leaf water potential. Emissions rapidly declined when the water potential dropped below -2 MPa and photosynthesis was persistently inhibited. Monoterpene synthase activities measured in vitro showed no clear reduction during the same period. From our results we conclude that drought significantly reduces monoterpene fluxes of Mediterranean Holm oak forest into the atmosphere due to a lack of primary substrates coming from photosynthetic processes.

  11. Aging effect on Zn retention on a calcareous soil: column experiments and synchrotron X-ray micro-spectroscopic investigation.

    PubMed

    Sayen, Stéphanie; Guillon, Emmanuel

    2014-07-15

    In this study, a combination of column experiments and micro-analytical techniques exploiting synchrotron generated X-rays was used to assess the effect of aging time on Zn retention and mobility in the specific case of calcareous soils (high pH value, ≈ 8). The samples were subjected to aging for 2, 6, 17, and 63 days. Freshly added Zn mainly existed as an exchangeable form, and this metal fraction decreased over time due to Zn redistribution to stronger binding sites. Thus, after aging for 63 days, 45% of Zn is remobilized from exchangeable sites to stronger binding sites. μ-XRF maps were used to find correlations among elements in the sample, and μ-XANES spectra were recorded to precise Zn speciation. These analyses evidenced an increasing partitioning of Zn from organic matter to iron oxy(hydr)oxides over time. The occurrence of hydrozincite is evidenced in all samples.

  12. An Inorganic Microsphere Composite for the Selective Removal of 137 Cesium from Acidic Nuclear Waste Solutions 2: Bench-Scale Column Experiments, Modeling, and Preliminary Process Design

    SciTech Connect

    Troy J. Tranter; T. A. Vereschagina; V. Utgikar

    2009-03-01

    A new inorganic ion exchange composite for removing radioactive cesium from acidic waste streams has been developed. The new material consists of ammonium molybdophosphate, (NH4)3P(Mo3O10)4?3H2O (AMP), synthesized within hollow aluminosilicate microspheres (AMP-C), which are produced as a by-product from coal combustion. The selective cesium exchange capacity of this inorganic composite was evaluated in bench-scale column tests using simulated sodium bearing waste solution as a surrogate for the acidic tank waste currently stored at the Idaho National Laboratory (INL). Total cesium loading on the columns at saturation agreed very well with equilibrium values predicted from isotherm experiments performed previously. A numerical algorithm for solving the governing partial differential equations (PDE) for cesium uptake was developed using the intraparticle mass transfer coefficient obtained from previous batch kinetic experiments. Solutions to the governing equations were generated to obtain the cesium concentration at the column effluent as a function of throughput volume using the same conditions as those used for the actual column experiments. The numerical solutions of the PDE fit the column break through data quite well for all the experimental conditions in the study. The model should therefore provide a reliable prediction of column performance at larger scales.

  13. Effects of Humidity Swings on Adsorption Columns for Air Revitalization: Modeling and Experiments

    NASA Technical Reports Server (NTRS)

    LeVan, M. Douglas; Finn, John E.

    1997-01-01

    The goal of this research was to develop a dynamic model which can predict the effect of humidity swings on activated carbon adsorption beds used to remove trace contaminants from the atmosphere in spacecraft. Specifically, the model was to be incorporated into a computer simulation to predict contaminant concentrations exiting the bed as a function of time after a humidity swing occurs. Predicted breakthrough curves were to be compared to experimentally measured results. In all respects the research was successful. The two major aspects of this research were the mathematical model and the experiments. Experiments were conducted by Mr. Appel using a fixed-bed apparatus at NASA-Ames Research Center during the summers of 1994 and 1995 and during the first 8 months of 1996. Mr. Appel conducted most of his mathematical modeling work at the University of Virginia. The simulation code was used to predict breakthrough curves using adsorption equilibrium correlations developed previously by M. D. LeVan's research group at the University of Virginia. These predictions were compared with the experimental measurements, and this led to improvements in both the simulation code and the apparatus.

  14. Column Experiments Investigating Wetting and Drying of Soil and Consumption of Organic Contaminants for Managed Aquifer Recharge

    NASA Astrophysics Data System (ADS)

    Silver, M.; Schueth, C.; Wefer-Roehl, A.; Kuebeck, C.

    2014-12-01

    The EU FP7 project MARSOL seeks to address water scarcity challenges in arid regions. Within this framework, we conduct a series of experiments to evaluate the potential for water quality improvement and changes in hydraulic conductivity when managed aquifer recharge (MAR) is performed by infiltrating treated wastewater in soils that do not have high potential for sorption. For example, in the Attica (Athens and vicinity) region of Greece, the bedrock is mostly marble, resulting in calcite-rich soils that present little potential for sorption of contaminants to mineral surfaces. This leaves consumption of organic contaminants by microbes as the critical mechanism for water quality improvement, when treated wastewater is infiltrated through such soils. In order to enhance the potential for contaminant consumption by aerobic bacteria in a way that would be realistic to later perform in an infiltration basin, we conduct experiments using a series of wetting and drying cycles. The experimental setup consists of 90-cm long soil columns, fitted with oxygen sensors, time-domain reflectometry sensors (to measure moisture content), sampling ports, oxidation-reduction probes, and head observation tubes. We use the data collected from these sensors and features of the experimental setup to answer the following questions: 1. Does hydraulic conductivity change, from formation of a biofilm or dissolution of calcite (or both)? 2. Are organic contaminants consumed? 3. What effect do wetting and drying cycles have on consumption of organic contaminants? 4. How long can infiltration of treated wastewater last, before oxygen is consumed and conditions become reducing? These questions are investigated by observing the hydraulic head and outflow, performing tracer tests, taking samples from the sampling ports and outflow for chemical analyses, and measuring moisture content and oxygen concentration, in the course of performing multiple wetting and drying cycles. These column

  15. Interpretation of column experiments of transport of solutes undergoing an irreversible bimolecular reaction using a continuum approximation

    NASA Astrophysics Data System (ADS)

    Sanchez-Vila, Xavier; Fernã Ndez-Garcia, Daniel; Guadagnini, Alberto

    2010-12-01

    We provide a quantitative interpretation of the column experiment reported by Gramling et al. (2002). The experiment involves advection-dominated transport in porous media of three dissolved species, i.e., two reactants undergoing a fast irreversible reaction and the resulting product. The authors found that their observations could not be properly fitted with a model based on an advection-dispersion-reaction equation (ADRE) assuming the reaction was instantaneous, the actual measured total reaction product being lower than predictions for all times. The data have been recently well reproduced by Edery et al. (2009, 2010) by means of a particle tracking approach in a continuous time random walk framework. These and other authors have questioned the use of partial differential equation (PDE)-based approaches to quantify reactive transport because of the difficulty in capturing local-scale mixing and reaction. We take precisely this approach and interpret the experiments mentioned by means of a continuum-scale model based on the ADRE. Our approach differs from previous modeling attempts in that we imbue effects of incomplete mixing at the pore scale in a time-dependent kinetic reaction term and show that this model allows quantitative interpretation of the experiments in terms of both reaction product profiles and time-dependent global production rate. The time dependence of the kinetic term presented accounts for the progressive effects of incomplete mixing due to pore-scale rate-limited mass transfer, and follows a power law, which is consistent with the compilation of existing experiments reported by Haggerty et al. (2004). Our interpretation can form the basis for further research to assess the potential use of PDE approaches for the interpretation of reactive transport problems in moderately heterogeneous media.

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

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

  17. Modelling of a viscoplastic granular column collapse and comparison with experiments

    NASA Astrophysics Data System (ADS)

    Martin, Nathan; Ionescu, Ioan; Mangeney, Anne; Bouchut, François; Roche, Olivier; Farin, Maxime

    2015-04-01

    Landslides and, more generally, large scale granular flows, represent a wide variety of geophysical flows also including mud or debris flow and snow avalanches. In a continuum mechanics context, the accurate simulation of these flows strongly depends on the modelling of their rheology and their boundary conditions, namely the sliding law and processes of erosion. In particular the description of the static and of the flowing states of granular media is still an open issue. We focus here on the quantitative reproduction of laboratory experiments using a mechanical and numerical model of dry granular flows with the so-called μ(I) rheology associated to a Drucker-Prager plasticity criterion and a shear rate and pressure dependent viscosity η(||D||,p). A Coulomb type friction law is considered at the base of the flow. The modelling is achieved in a finite-element context using the software FreeFem++. The simulations are bidimensionnal and well reproduce quantitatively both the dynamical and final shapes of the deposit. The effects of the sidewalls of the experimental channel, neglected in 2D simulations, are investigated by introducing an extra term in the equations varying with the inverse of the width of the channel, providing an enhanced agreement with the experiments. The numerical results show that the flow is essentially located in a surface layer behind the front, while the whole granular material is flowing near the front where basal sliding occurs. The static/flowing interface changes as a function of space and time, in good agreement with experimental observations. The resulting dynamic viscosity varies from very small values near the free surface and near the front to 1.5Pa.s within the quasi-static zone. The results show a rather small yet computationnaly expensive difference between a constant viscosity model and a μ(I) rheology in the case of a rigid bed. This has important implication for application to real geophysical flows. The role of an erodible

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

    PubMed

    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

  19. Adapting to variable prismatic displacement

    NASA Technical Reports Server (NTRS)

    Welch, Robert B.; Cohen, Malcolm M.

    1989-01-01

    In each of two studies, subjects were exposed to a continuously changing prismatic displacement with a mean value of 19 prism diopters (variable displacement) and to a fixed 19-diopter displacement (fixed displacement). In Experiment 1, significant adaptation (post-pre shifts in hand-eye coordination) was found for fixed, but not for variable, displacement. Experiment 2 demonstrated that adaptation was obtained for variable displacement, but it was very fragile and is lost if the measures of adaptation are preceded by even a very brief exposure of the hand to normal or near-normal vision. Contrary to the results of some previous studies, an increase in within-S dispersion was not found of target pointing responses as a result of exposure to variable displacement.

  20. Colloid facilitated transport of strongly sorbing contaminants in natural porous media: mathematical modeling and laboratory column experiments.

    PubMed

    Grolimund, Daniel; Borkovec, Michal

    2005-09-01

    Mobile colloidal particles may act as carriers of strongly sorbing contaminants in subsurface materials. Such colloid-facilitated transport can be induced by changes in salinity, similar to freshwater intrusion to a contaminated aquifer saturated with saltwater, or groundwater penetration into a contaminated site saturated with a dumpsite leachate. This process is studied for noncalcareous soil material with laboratory column experiments with sodium and calcium as major cations and with lead as a strongly sorbing model contaminant. The measured breakthrough curves of these elements were described with a mathematical transport model, which invokes release and deposition kinetics of the colloids, together with adsorption and desorption of the relevant ions to the solid matrix as well as to the suspended colloids. In particular, the specific coupling between colloid and solute transport is considered. The crux of a successful description of such colloidal transport processes is to capture the inhibition of the particle release by adsorbed divalent ions properly and explicitly to considerthe dependence of colloid release on the solution chemistry and the chemical conditions at the solid-liquid interface. Experiments and modeling address colloid-facilitated transport of lead out of a contaminated zone and through a noncontaminated zone, including effects of flow velocity and length of the noncontaminated zone. We finally show that colloid-facilitated transport can be suppressed by the injection of a suitably chosen solution of a calcium salt.

  1. Modelling of geochemical and isotopic changes in a column experiment for degradation of TCE by zero-valent iron.

    PubMed

    Prommer, Henning; Aziz, Lidia H; Bolaño, Nerea; Taubald, Heinrich; Schüth, Christoph

    2008-04-01

    Zero-valent iron (ZVI) permeable-reactive barriers have become an increasingly used remediation option for the in situ removal of various organic and inorganic chemicals from contaminated groundwater. In the present study a process-based numerical model for the transport and reactions of chlorinated hydrocarbon in the presence of ZVI has been developed and applied to analyse a comprehensive data set from laboratory-scale flow-through experiments. The model formulation includes a reaction network for the individual sequential and/or parallel transformation of chlorinated hydrocarbons by ZVI, for the resulting geochemical changes such as mineral precipitation, and for the carbon isotope fractionation that occurs during each of the transformation reactions of the organic compounds. The isotopic fractionation was modelled by formulating separate reaction networks for lighter ((12)C) and heavier ((13)C) isotopes. The simulation of a column experiment involving the parallel degradation of TCE by hydrogenolysis and beta-elimination can conclusively reproduce the observed concentration profiles of all collected organic and inorganic data as well as the observed carbon isotope ratios of TCE and its daughter products.

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

    PubMed

    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.

  3. Starch columns: Analog model for basalt columns

    NASA Astrophysics Data System (ADS)

    Müller, Gerhard

    1998-07-01

    Desiccation of starch-water mixtures produces tensile-crack patterns which appear to be interesting, but largely unknown study objects for fracture mechanics, structural geology, and volcanology. This paper concentrates on columnar jointing and on columns in starch. Starch columns have polygonal cross sections and are very similar to basalt columns. They are produced by lamp drying starch specimens with dimensions of several centimeters and have diameters in the millimeter range. The columns develop behind a crack front which propagates from the surface into the interior. The experiments, supported by X ray tomograms, show that polygonal regularity of the crack pattern is not present at the surface but develops during penetration. This transition is steered by a minimum-fracture-energy principle. The analogy between basalt cooling and starch desiccation is far reaching: water concentration in starch is analogous to temperature in basalt, both quantities obey diffusion equations, water loss is equivalent to heat loss, the resulting contraction stresses have similar dependences on depth and time, and in both cases the material strength is exceeded. The starch experiments show that column diameters are controlled by the depth gradient of water concentration at the crack front. High (low) gradients are connected with thin (thick) columns. By analogy, a similar relation with the temperature gradient exists for basalt columns. The (normalized) starch gradients are about 3 orders of magnitude larger than the (normalized) gradients in basalt. This explains why starch columns are much thinner than basalt columns. The gradients are so different, because the crack front speeds differ by a factor of about 10: after 3 days the speed is about 10 mm/d in starch but about 100 mm/d in basalt [Peck, 1978]. The speed difference, in turn, results from the difference of the diffusion constants: the hydraulic diffusivity of starch is 2 orders of magnitude lower than the thermal

  4. Cation Uptake and Allocation by Red Pine Seedlings under Cation-Nutrient Stress in a Column Growth Experiment

    SciTech Connect

    Shi, Zhenqing; Balogh-Brunstad, Zsuzsanna; Grant, Michael R.; Harsh, James B.; Gill, Richard; Thomashow, Linda; Dohnalkova, Alice; Stacks, Daryl; Letourneau, Melissa; Keller, Chester K.

    2014-01-10

    Background and Aims Plant nutrient uptake is affected by environmental stress, but how plants respond to cation-nutrient stress is poorly understood. We assessed the impact of varying degrees of cation-nutrient limitation on cation uptake in an experimental plant-mineral system. Methods Column experiments, with red pine (Pinus resinosa Ait.) seedlings growing in sand/mineral mixtures, were conducted for up to nine months under a range of Ca- and K-limited conditions. The Ca and K were supplied from both minerals and nutrient solutions with varying Ca and K concentrations. Results Cation nutrient stress had little impact on carbon allocation after nine months of plant growth and K was the limiting nutrient for biomass production. The Ca/Sr and K/Rb ratio results allowed independent estimation of dissolution incongruency and discrimination against Sr and Rb during cation uptake processes. The fraction of K in biomass from biotite increased with decreasing K supply from nutrient solutions. The mineral anorthite was consistently the major source of Ca, regardless of nutrient treatment. Conclusions Red pine seedlings exploited more mineral K in response to more severe K deficiency. This did not occur for Ca. Plant discrimination factors must be carefully considered to accurately identify nutrient sources using cation tracers.

  5. Sorption behavior of 20 wastewater originated micropollutants in groundwater — Column experiments with pharmaceutical residues and industrial agents

    NASA Astrophysics Data System (ADS)

    Burke, Victoria; Treumann, Svantje; Duennbier, Uwe; Greskowiak, Janek; Massmann, Gudrun

    2013-11-01

    Since sorption is an essential process with regard to attenuation of organic pollutants during subsurface flow, information on the sorption properties of each pollutant are essential for assessing their environmental fate and transport behavior. In the present study, the sorption behavior of 20 wastewater originated organic micropollutants was assessed by means of sediment column experiments, since experimentally determined data for these compounds are not or sparsely represented in the literature. Compounds investigated include various psychoactive drugs, phenazone-type pharmaceuticals and β-blockers, as well as phenacetine, N-methylphenacetine, tolyltriazole and para-toluenesulfonamide. While for most of the compounds no or only a low sorption affinity was observed, an elevated tendency to sorb onto aquifer sand was obtained for the β-blockers atenolol, propranolol and metoprolol. A comparison between experimental data and data estimated based on the octanol/water partition coefficient following the QSAR approach demonstrated the limitations of the latter to predict the adsorption behavior in natural systems for the studied compounds.

  6. Sorption behavior of 20 wastewater originated micropollutants in groundwater--column experiments with pharmaceutical residues and industrial agents.

    PubMed

    Burke, Victoria; Treumann, Svantje; Duennbier, Uwe; Greskowiak, Janek; Massmann, Gudrun

    2013-11-01

    Since sorption is an essential process with regard to attenuation of organic pollutants during subsurface flow, information on the sorption properties of each pollutant are essential for assessing their environmental fate and transport behavior. In the present study, the sorption behavior of 20 wastewater originated organic micropollutants was assessed by means of sediment column experiments, since experimentally determined data for these compounds are not or sparsely represented in the literature. Compounds investigated include various psychoactive drugs, phenazone-type pharmaceuticals and β-blockers, as well as phenacetine, N-methylphenacetine, tolyltriazole and para-toluenesulfonamide. While for most of the compounds no or only a low sorption affinity was observed, an elevated tendency to sorb onto aquifer sand was obtained for the β-blockers atenolol, propranolol and metoprolol. A comparison between experimental data and data estimated based on the octanol/water partition coefficient following the QSAR approach demonstrated the limitations of the latter to predict the adsorption behavior in natural systems for the studied compounds. PMID:24077094

  7. Reactive transport modeling of thermal column experiments to investigate the impacts of aquifer thermal energy storage on groundwater quality.

    PubMed

    Bonte, Matthijs; Stuyfzand, Pieter J; Breukelen, Boris M van

    2014-10-21

    Aquifer thermal energy storage (ATES) systems are increasingly being used to acclimatize buildings and are often constructed in aquifers used for drinking water supply. This raises the question of potential groundwater quality impact. Here, we use laboratory column experiments to develop and calibrate a reactive transport model (PHREEQC) simulating the thermally induced (5-60 °C) water quality changes in anoxic sandy sediments. Temperature-dependent surface complexation, cation-exchange, and kinetic dissolution of K-feldspar were included in the model. Optimization results combined with an extensive literature survey showed surface complexation of (oxy)anions (As, B, and PO4) is consistently exothermic, whereas surface complexation of cations (Ca and Mg) and cationic heavy metals (Cd, Pb, and Zn) is endothermic. The calibrated model was applied to simulate arsenic mobility in an ATES system using a simple yet powerful mirrored axi-symmetrical grid. Results showed that ATES mobilizes arsenic toward the fringe of the warm water bubble and the center of the cold water bubble. This transient redistribution of arsenic causes its aqueous concentrations in the cold and warm groundwater bubbles to become similar through multiple heating cycles, with a final concentration depending on the average injection temperature of the warm and cold ATES wells.

  8. Bench-scale column experiments to study the containment of Cr(VI) in confined aquifers by bio-transformation.

    PubMed

    Shashidhar, T; Philip, Ligy; Murty Bhallamudi, S

    2006-04-17

    Bench-scale soil column experiments were conducted to study the effectiveness of Cr(VI) containment in confined aquifers using in situ bio-transformation. Batch adsorption studies were carried out to estimate the adsorption capacities of two different soils for Cr(VI) and Cr(III). Bio-kinetic parameters were evaluated for the enriched microbial system. The inhibition constant, evaluated using Monod's inhibition model, was found to be 11.46 mg/L of Cr(VI). Transport studies indicated that it would not be possible to contain Cr(VI) by adsorption alone. Transport and bio-transformation studies indicated that the pore velocity and the initial bio-mass concentration significantly affect the containment process. In situ bio-remediation is effective in the case of silty aquifers. Cr(VI) concentration of 25 mg/L was effectively contained within 60 cm of a confined silty aquifer. Cr(VI) containment could be achieved in sandy aquifers when the pore velocity was very low and the initial augmented bio-mass was high. A bio-barrier of approximately one meter width would be able to contain Cr(VI) if the initial Cr(VI) concentration is as much as 25 mg/L.

  9. Adsorption and transformation of ammonium ion in a loose-pore geothermal reservoir: Batch and column experiments.

    PubMed

    Zhao, Li; Li, Yanli; Wang, Shidong; Wang, Xinyi; Meng, Hongqi; Luo, Shaohe

    2016-09-01

    Adsorption kinetics and transformation process of ammonium ion (NH4(+)) were investigated to advance the understanding of N cycle in a low-temperature loose-pore geothermal reservoir. Firstly, batch experiments were performed in order to determine the sorption capacity and the kinetic mechanism of NH4(+) onto a loose-pore geothermal reservoir matrix. Then column experiments were carried out at temperatures from 20°C to 60°C in order to determine the transport parameters and transformation mechanism of NH4(+) in the studied matrix. The results showed that the adsorption process of NH4(+) onto the porous media well followed the pseudo-second-order model. No obvious variation of hydrodynamic dispersion coefficient (D) and retardation factor (R) was observed at different transport distances at a Darcy's flux of 2.27cm/h, at which nitrification could be neglected. The simulated D obtained by the CDE model in CXTFIT2.1 increased with temperature while R decreased with temperature, indicating that the adsorption capacity of NH4(+) onto the matrix decreased with the increasing of temperature. When the Darcy's flux was decreased to 0.014cm/h, only a little part of NH4(+) could be transformed to nitrate, suggesting that low density of nitrifiers existed in the simulated loose-pore geothermal reservoir. Although nitrification rate increased with temperature in the range of 20°C to 60°C, it was extremely low and no accumulation of nitrite was observed under the simulated low-temperature geothermal conditions without addition of biomass and oxygen. PMID:27356192

  10. Adsorption and transformation of ammonium ion in a loose-pore geothermal reservoir: Batch and column experiments.

    PubMed

    Zhao, Li; Li, Yanli; Wang, Shidong; Wang, Xinyi; Meng, Hongqi; Luo, Shaohe

    2016-09-01

    Adsorption kinetics and transformation process of ammonium ion (NH4(+)) were investigated to advance the understanding of N cycle in a low-temperature loose-pore geothermal reservoir. Firstly, batch experiments were performed in order to determine the sorption capacity and the kinetic mechanism of NH4(+) onto a loose-pore geothermal reservoir matrix. Then column experiments were carried out at temperatures from 20°C to 60°C in order to determine the transport parameters and transformation mechanism of NH4(+) in the studied matrix. The results showed that the adsorption process of NH4(+) onto the porous media well followed the pseudo-second-order model. No obvious variation of hydrodynamic dispersion coefficient (D) and retardation factor (R) was observed at different transport distances at a Darcy's flux of 2.27cm/h, at which nitrification could be neglected. The simulated D obtained by the CDE model in CXTFIT2.1 increased with temperature while R decreased with temperature, indicating that the adsorption capacity of NH4(+) onto the matrix decreased with the increasing of temperature. When the Darcy's flux was decreased to 0.014cm/h, only a little part of NH4(+) could be transformed to nitrate, suggesting that low density of nitrifiers existed in the simulated loose-pore geothermal reservoir. Although nitrification rate increased with temperature in the range of 20°C to 60°C, it was extremely low and no accumulation of nitrite was observed under the simulated low-temperature geothermal conditions without addition of biomass and oxygen.

  11. Adsorption and transformation of ammonium ion in a loose-pore geothermal reservoir: Batch and column experiments

    NASA Astrophysics Data System (ADS)

    Zhao, Li; Li, Yanli; Wang, Shidong; Wang, Xinyi; Meng, Hongqi; Luo, Shaohe

    2016-09-01

    Adsorption kinetics and transformation process of ammonium ion (NH4+) were investigated to advance the understanding of N cycle in a low-temperature loose-pore geothermal reservoir. Firstly, batch experiments were performed in order to determine the sorption capacity and the kinetic mechanism of NH4+ onto a loose-pore geothermal reservoir matrix. Then column experiments were carried out at temperatures from 20 °C to 60 °C in order to determine the transport parameters and transformation mechanism of NH4+ in the studied matrix. The results showed that the adsorption process of NH4+ onto the porous media well followed the pseudo-second-order model. No obvious variation of hydrodynamic dispersion coefficient (D) and retardation factor (R) was observed at different transport distances at a Darcy's flux of 2.27 cm/h, at which nitrification could be neglected. The simulated D obtained by the CDE model in CXTFIT2.1 increased with temperature while R decreased with temperature, indicating that the adsorption capacity of NH4+ onto the matrix decreased with the increasing of temperature. When the Darcy's flux was decreased to 0.014 cm/h, only a little part of NH4+ could be transformed to nitrate, suggesting that low density of nitrifiers existed in the simulated loose-pore geothermal reservoir. Although nitrification rate increased with temperature in the range of 20 °C to 60 °C, it was extremely low and no accumulation of nitrite was observed under the simulated low-temperature geothermal conditions without addition of biomass and oxygen.

  12. Column Experiments for Radionuclide Adsorption Studies of the Culebra Dolomite: Retardation Parameter Estimation for Non-Eluted Actinide Species

    SciTech Connect

    Brown, G.O.; Lucero, D.A.; Perkins, W.G.

    1999-01-01

    The U.S. Department of Energy (DOE) has been developing a nuclear waste disposal facility, the Waste Isolation Pilot Plant (WIPP), located approximately 42 km east of Carlsbad, New Mexico. The WIPP is designed to demonstrate the safe disposal of transuranic wastes produced by the defense nuclear-weapons program. Performance assessment analyses (U.S. DOE, 1996) indicate that human intrusion by inadvertent and intermittent drilling for resources provide the only credible mechanisms for significant releases of radionuclides horn the disposal system. These releases may occur by five mechanisms: (1) cuttings, (2) cavings, (3) spallings, (4) direct brine releases, and (5) long-term brine releases. The first four mechanisms could result in immediate release of contaminant to the accessible environment. For the last mechanism, migration pathways through the permeable layers of rock above the Salado are important, and major emphasis is placed on the Culebra Member of the Rustler Formation because this is the most transmissive geologic layer in the disposal system. For reasons of initial quantity, half-life, and specific radioactivity, certain isotopes of Th, U, Am, and Pu would dominate calculated releases from the WIPP. In order to help quanti~ parameters for the calculated releases, radionuclide transport experiments have been carried out using five intact-core columns obtained from the Culebra dolomite member of the Rustler Formation within the Waste Isolation Pilot Plant (WIPP) site in southeastern New Mexico. This report deals primarily with results of mathematical analyses related to the retardation of %J%, 24%, and 24'Am in two of these cores (B-Core - VPX26-11A and C-Core - VPX28-6C). All B-Core transport experiments were done using Culebra-simukmt brine relevant to the core recovery location (the WIPP air-intake shaft - AIS). Most experiments with C-Core were done with AIS brine with some admixture of a brine composition (ERDA-6) that simulated deeper formation

  13. Utilization of fly ash to improve the quality of the acid mine drainage generated by oxidation of a sulphide-rich mining waste: column experiments.

    PubMed

    Pérez-López, Rafael; Nieto, José Miguel; de Almodóvar, Gabriel Ruiz

    2007-04-01

    The production of Acid Mine Drainage (AMD) as a result of the oxidative dissolution of sulphides is one of the main pollution problems affecting natural watercourses in mining environments with sulphide-rich residues. In this work, the generation of AMD was prevented by means of the addition of fly ash to sulphide-rich residues in non-saturated column experiments. A column experiment filled with a pyrite-rich sludge with artificial irrigation leached acid drainages (pH approx. 2) containing high concentrations of sulphate, iron and other metals. However, non-saturated column experiments filled with pyritic-rich sludge and fly ash drained leachates characterized by alkaline pH (pH up to 10), low sulphate concentration, and lack of iron and other metals in solution. The pyrite oxidative dissolution at high pH, as a consequence of the leaching of fly ash, favours the metal precipitation inside the column (mainly iron), the coating of pyrite grains, and the attenuation of the oxidation process, resulting in a great improvement in the quality of the leachates.

  14. Analysis of the impact of surface layer properties on evaporation from porous systems using column experiments and modified definition of characteristic length

    NASA Astrophysics Data System (ADS)

    Assouline, Shmuel; Narkis, Kfir; Gherabli, Rivka; Lefort, Philippe; Prat, Marc

    2014-05-01

    The hydraulic properties of the layer at the vicinity of the soil surface have significant impact on evaporation and could be harnessed to reduce water losses. The effect of the properties of the upper layer on the evolution of phase distribution during the evaporation process is first illustrated from three-dimensional pore network simulations. This effect is then studied from experiments carried out on soil columns under laboratory conditions. Comparisons between homogeneous columns packed with coarse (sand) and fine (sandy loam) materials and heterogeneous columns packed with layers of fine overlying coarse material and coarse overlying fine material of different thicknesses are performed to assess the impact of upper layer properties on evaporation. Experiments are analyzed using the classical approach based on the numerical solution of Richards equation and semianalytical theoretical predictions. The theoretical analysis is based on the clear distinction between two drying regimes, namely, the capillary regime and the gravity-capillary regime, which are the prevailing regimes in our experiments. Simple relationships enabling to estimate the duration of stage 1 evaporation (S1) for both regimes are proposed. In particular, this led to defining the characteristic length for the gravity-capillary regime from the consideration of viscous effects at low water content differently from available expressions. The duration of S1, during which most of the water losses occur, for both the homogeneous and two-layer columns is presented and discussed. Finally, the impact of liquid films and its consequences on the soil hydraulic conductivity function are briefly discussed.

  15. Utilization of fly ash to improve the quality of the acid mine drainage generated by oxidation of a sulphide-rich mining waste: column experiments.

    PubMed

    Pérez-López, Rafael; Nieto, José Miguel; de Almodóvar, Gabriel Ruiz

    2007-04-01

    The production of Acid Mine Drainage (AMD) as a result of the oxidative dissolution of sulphides is one of the main pollution problems affecting natural watercourses in mining environments with sulphide-rich residues. In this work, the generation of AMD was prevented by means of the addition of fly ash to sulphide-rich residues in non-saturated column experiments. A column experiment filled with a pyrite-rich sludge with artificial irrigation leached acid drainages (pH approx. 2) containing high concentrations of sulphate, iron and other metals. However, non-saturated column experiments filled with pyritic-rich sludge and fly ash drained leachates characterized by alkaline pH (pH up to 10), low sulphate concentration, and lack of iron and other metals in solution. The pyrite oxidative dissolution at high pH, as a consequence of the leaching of fly ash, favours the metal precipitation inside the column (mainly iron), the coating of pyrite grains, and the attenuation of the oxidation process, resulting in a great improvement in the quality of the leachates. PMID:17257643

  16. Sample displacement batch chromatography of proteins.

    PubMed

    Kotasinska, Marta; Richter, Verena; Kwiatkowski, Marcel; Schlüter, Hartmut

    2014-01-01

    In downstream processing large scale chromatography plays an important role. For its development screening experiments followed by pilot plant chromatography are mandatory steps. Here we describe fast, simple, and inexpensive methods for establishing a preparative chromatography for the separation of complex protein mixtures, based on sample displacement batch chromatography. The methods are demonstrated by anion-exchange chromatography of a human plasma protein fraction (Cohn IV-4), including the screening step and scaling up of the chromatography by a factor of 100. The results of the screening experiments and the preparative chromatography are monitored by SDS-PAGE electrophoresis. In summary we provide a protocol which should be easily adaptable for the chromatographic large scale purification of other proteins, in the laboratory as well as in industry for commercial manufacturing. For the latter these protocols cover the initial piloting steps for establishing a sample batch chromatography based on packed columns rather than batch chromatography. PMID:24648085

  17. Effects of Low-Molecular-Weight Organic Acids on the Dissolution of Hydroxyapatite Nanoparticles in Batch and Column Experiments: A Perspective from Phosphate Oxygen Isotope Fractionation

    NASA Astrophysics Data System (ADS)

    Wang, D.; Jaisi, D. P.; Jin, Y.

    2015-12-01

    Hydroxyapatite nanoparticles (HANPs) are increasingly being advocated as an efficient and environment-friendly "green" phosphorus nanofertilizer attributed to their nanoscale dimension, large reactive surface area, and low leaching potential. However, knowledge of how naturally occurring low-molecular-weight organic acids (LMWOAs) that are secreted by plant roots mediate the dissolution of HANPs (releasing PO43- ion for plant growth) is nonexistent. Here three most commonly encountered LMWOAs (acetic acid, oxalic acid, and citric acid) at environmentally relevant concentration (1 mM) were evaluated for their effects on HANPs' dissolution in static batch and dynamic column systems. Particularly, phosphate oxygen isotope fractionation of HANPs during dissolution was examined to disentangle mechanisms controlling the evolution of O-isotopic composition of dissolved PO43- ion. Our results reveal that in batch experiments the dissolution of HANPs was fast but the overall dissolution efficiency of HANPs was limited (≤30%). In contrast, ~100% HANPs were dissolved in columns where LMWOAs were continuously injected. The limited dissolution of HANPs in static batch systems was due primarily to pH buffer effect (pH increased sharply when LMWOA was added in HANPs suspension), whereas in dynamic column systems the HANPs were continuously dissolved by low pH LMWOAs and leached away. Regardless of LMWOA type and experimental system, the isotopically light phosphate (P16O4) was preferentially released during dissolution and the O-isotopic composition of dissolved PO43- ion increased gradually with increasing dissolution due to equilibrium isotope effect between dissolved PO43- ion and HANPs. However, the overall magnitude of O-isotopic fractionation of dissolved PO43- ion was less in batch than in column systems, due to less mass transfer between dissolved PO43- ions and HANPs in batch relative to column experiments. Our findings provide new insights into bioavailability

  18. Displacement phenomena in lectin affinity chromatography.

    PubMed

    Cho, Wonryeon

    2015-10-01

    The work described here examines displacement phenomena that play a role in lectin affinity chromatography and their potential to impact reproducibility. This was achieved using Lycopersicon esculentum lectin (LEL), a lectin widely used in monitoring cancer. Four small identical LEL columns were coupled in series to form a single affinity chromatography system with the last in the series connected to an absorbance detector. The serial affinity column set (SACS) was then loaded with human plasma proteins. At the completion of loading, the column set was disassembled, the four columns were eluted individually, the captured proteins were trypsin digested, the peptides were deglycosylated with PNGase F, and the parent proteins were identified through mass spectral analyses. Significantly different sets of glycoproteins were selected by each column, some proteins appearing to be exclusively bound to the first column while others were bound further along in the series. Clearly, sample displacement chromatography (SDC) occurs. Glycoproteins were bound at different places in the column train, identifying the presence of glycoforms with different affinity on a single glycoprotein. It is not possible to see these phenomena in the single column mode of chromatography. Moreover, low abundance proteins were enriched, which facilitates detection. The great advantage of this method is that it differentiates between glycoproteins on the basis of their binding affinity. Displacement phenomena are concluded to be a significant component of the separation mechanism in heavily loaded lectin affinity chromatography columns. This further suggests that care must be exercised in sample loading of lectin columns to prevent analyte displacement with nonretained proteins. PMID:26348026

  19. Transport of carboxyl-functionalized carbon black nanoparticles in saturated porous media: Column experiments and model analyses

    NASA Astrophysics Data System (ADS)

    Kang, Jin-Kyu; Yi, In-Geol; Park, Jeong-Ann; Kim, Song-Bae; Kim, Hyunjung; Han, Yosep; Kim, Pil-Je; Eom, Ig-Chun; Jo, Eunhye

    2015-06-01

    The aim of this study was to investigate the transport behavior of carboxyl-functionalized carbon black nanoparticles (CBNPs) in porous media including quartz sand, iron oxide-coated sand (IOCS), and aluminum oxide-coated sand (AOCS). Two sets of column experiments were performed under saturated flow conditions for potassium chloride (KCl), a conservative tracer, and CBNPs. Breakthrough curves were analyzed to obtain mass recovery and one-dimensional transport model parameters. The first set of experiments was conducted to examine the effects of metal (Fe, Al) oxides and flow rate (0.25 and 0.5 mL min- 1) on the transport of CBNPs suspended in deionized water. The results showed that the mass recovery of CBNPs in quartz sand (flow rate = 0.5 mL min- 1) was 83.1%, whereas no breakthrough of CBNPs (mass recovery = 0%) was observed in IOCS and AOCS at the same flow rate, indicating that metal (Fe, Al) oxides can play a significant role in the attachment of CBNPs to porous media. In addition, the mass recovery of CBNPs in quartz sand decreased to 76.1% as the flow rate decreased to 0.25 mL min- 1. Interaction energy profiles for CBNP-porous media were calculated using DLVO theory for sphere-plate geometry, demonstrating that the interaction energy for CBNP-quartz sand was repulsive, whereas the interaction energies for CBNP-IOCS and CBNP-AOCS were attractive with no energy barriers. The second set of experiments was conducted in quartz sand to observe the effect of ionic strength (NaCl = 0.1 and 1.0 mM; CaCl2 = 0.01 and 0.1 mM) and pH (pH = 4.5 and 5.4) on the transport of CBNPs suspended in electrolyte. The results showed that the mass recoveries of CBNPs in NaCl = 0.1 and 1.0 mM were 65.3 and 6.4%, respectively. The mass recoveries of CBNPs in CaCl2 = 0.01 and 0.1 mM were 81.6 and 6.3%, respectively. These results demonstrated that CBNP attachment to quartz sand can be enhanced by increasing the electrolyte concentration. Interaction energy profiles demonstrated that

  20. Transport of carboxyl-functionalized carbon black nanoparticles in saturated porous media: Column experiments and model analyses.

    PubMed

    Kang, Jin-Kyu; Yi, In-Geol; Park, Jeong-Ann; Kim, Song-Bae; Kim, Hyunjung; Han, Yosep; Kim, Pil-Je; Eom, Ig-Chun; Jo, Eunhye

    2015-01-01

    The aim of this study was to investigate the transport behavior of carboxyl-functionalized carbon black nanoparticles (CBNPs) in porous media including quartz sand, iron oxide-coated sand (IOCS), and aluminum oxide-coated sand (AOCS). Two sets of column experiments were performed under saturated flow conditions for potassium chloride (KCl), a conservative tracer, and CBNPs. Breakthrough curves were analyzed to obtain mass recovery and one-dimensional transport model parameters. The first set of experiments was conducted to examine the effects of metal (Fe, Al) oxides and flow rate (0.25 and 0.5 mL min(-1)) on the transport of CBNPs suspended in deionized water. The results showed that the mass recovery of CBNPs in quartz sand (flow rate=0.5 mL min(-1)) was 83.1%, whereas no breakthrough of CBNPs (mass recovery=0%) was observed in IOCS and AOCS at the same flow rate, indicating that metal (Fe, Al) oxides can play a significant role in the attachment of CBNPs to porous media. In addition, the mass recovery of CBNPs in quartz sand decreased to 76.1% as the flow rate decreased to 0.25 mL min(-1). Interaction energy profiles for CBNP-porous media were calculated using DLVO theory for sphere-plate geometry, demonstrating that the interaction energy for CBNP-quartz sand was repulsive, whereas the interaction energies for CBNP-IOCS and CBNP-AOCS were attractive with no energy barriers. The second set of experiments was conducted in quartz sand to observe the effect of ionic strength (NaCl=0.1 and 1.0mM; CaCl2=0.01 and 0.1mM) and pH (pH=4.5 and 5.4) on the transport of CBNPs suspended in electrolyte. The results showed that the mass recoveries of CBNPs in NaCl=0.1 and 1.0mM were 65.3 and 6.4%, respectively. The mass recoveries of CBNPs in CaCl2=0.01 and 0.1mM were 81.6 and 6.3%, respectively. These results demonstrated that CBNP attachment to quartz sand can be enhanced by increasing the electrolyte concentration. Interaction energy profiles demonstrated that the

  1. Americium, Cesium, and Plutonium Colloid-Facilitated Transport in a Groundwater/Bentonite/Fracture Fill Material System: Column Experiments and Model Results

    NASA Astrophysics Data System (ADS)

    Dittrich, T. M.; Boukhalfa, H.; Reimus, P. W.

    2014-12-01

    The objective of this study was to investigate and quantify the effects of desorption kinetics and colloid transport on radionuclides with different sorption affinities. We focused on quantifying transport mechanisms important for upscaling in time and distance. This will help determine the long-term fate and transport of radionuclides to aid in risk assessments. We selected a fractured/weathered granodiorite at the Grimsel Test Site (GTS) in Switzerland as a model crystalline rock repository system because the system has been thoroughly studied and field experiments involving radionuclides have already been conducted. Working on this system provides a unique opportunity to compare lab experiments with field-scale observations. Weathered fracture fill material (FFM) and bentonite used as backfill at the GTS were characterized (e.g., BET, SEM/EDS, QXRD), and batch and breakthrough column experiments were conducted. Solutions were prepared in synthetic groundwaters that matched the natural water chemistry. FFM samples were crushed, rinsed, sieved (150-355 μm), and equilibrated with synthetic groundwater. Bentonite was crushed, sodium-saturated, equilibrated with synthetic groundwater, and settled to yield a stable suspension. Suspensions were equilibrated with Am, Cs, or Pu. All experiments were conducted with Teflon®materials to limit sorption to system components. After radionuclide/colloid injections reached stability, radionuclide-free solutions were injected to observe the desorption and release behavior. Aliquots of effluent were measured for pH, colloid concentration, and total and dissolved radionuclides. Unanalyzed effluent from the first column was then injected through a second column of fresh material. The process was repeated for a third column and the results of all three breakthrough curves were modeled with a multi-site/multi-rate MATLAB code to elucidate the sorption rate coefficients and binding site densities of the bentonite colloids and

  2. 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.

    PubMed

    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.

  3. Closed-Flow Column Experiments - A Numerical Study on Breakthrough Oscillations Reveals a Decreased Uncertainty in the Inverse Determination of Transport Parameters

    NASA Astrophysics Data System (ADS)

    Ritschel, Thomas; Totsche, Kai Uwe

    2016-04-01

    The identification of transport parameters by inverse modeling often suffers from large uncertainties due to equifinality or parameter correlation when models are fitted to observations of the solute breakthrough in column outflow experiments. This issue can be approached by increasing the information potential of the observation, e.g. by running multiple experiments at different boundary conditions. A promising complementary approach of designing soil column experiments in order to further increase the obtained information is the closed-flow mode that is characterized by the recirculation of the effluent solution into the solution supply vessel. Depending on the experimental conditions, the solute concentration in the mixing vessel and the effluent follows a damped sinusoidal oscillation. As a result, the closed-flow experiment provides additional observables in the breakthrough curve, which are the initial exponential decrease in concentration in mixing vessel concentration, the oscillation wavelength and the extent of damping, each indicative for corresponding transport parameters. Furthermore, the concentration in the porous medium and the mixing vessel converges to equilibrium due to the closed loop. The evaluation of these emergent features allows intrinsic control over boundary conditions and impacts the uncertainty of parameters in inverse modeling. We present a comprehensive numerical sensitivity analysis to illustrate the potential application of closed-flow experiments. We can show that the sensitivity with respect to the apparent dispersion can be controlled by the experimenter leading to a decrease in parameter uncertainty as compared to classical experiments by an order of magnitude for optimal settings. With these finding we are also able to show a reduction of equifinality found for situations, where rate-limited interactions impede a proper determination of the apparent dispersion and rate coefficients. This renders the closed-flow mode a useful

  4. Polyimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul M.

    1990-01-01

    Experiments show variety of polyimidazoles prepared by aromatic nucleophilic displacement, from reactions of bisphenol imidazoles with activated difluoro compounds. Polyimidazoles have good mechanical properties making them suitable for use as films, moldings, and adhesives.

  5. Measuring vulnerability to disaster displacement

    NASA Astrophysics Data System (ADS)

    Brink, Susan A.; Khazai, Bijan; Power, Christopher; Wenzel, Friedemann

    2015-04-01

    aggregate these ideas into a framework of disaster displacement vulnerability that distinguishes between three main aspects of disaster displacement. Disaster displacement can be considered in terms of the number of displaced people and the length of that displacement. However, the literature emphasizes that the severity of disaster displacement can not be measured completely in quantitative terms. Thus, we include a measure representing people who are trapped and unable to leave their homes due to mobility, resources or for other reasons. Finally the third main aspect considers the difficulties that are associated with displacement and reflects the difference between the experiences of those who are displaced into safe and supportive environments as compared to those whose only alternate shelter is dangerous and inadequate for their needs. Finally, we apply the framework to demonstrate a methodology to estimate vulnerability to disaster displacement. Using data from the Global Earthquake Model (GEM) Social and Economic Vulnerability sub-National Database, we generate an index to measure the vulnerability of Japanese prefectures to the dimensions of displacement included in the framework. References Yonitani, M. (2014). Global Estimates 2014: People displaced by disasters. http://www.internal-displacement.org/publications/2014/global-estimates-2014-people-displaced-by-disasters/

  6. [60]Fullerene Displacement from (Dihapto-Buckminster-Fullerene) Pentacarbonyl Tungsten(0): An Experiment for the Inorganic Chemistry Laboratory, Part II

    ERIC Educational Resources Information Center

    Cortes-Figueroa, Jose E.; Moore-Russo, Deborah A.

    2006-01-01

    The kinetics experiments on the ligand-C[subscript 60] exchange reactions on (dihapto-[60]fullerene) pentacarbonyl tungsten(0), ([eta][superscript 2]-C[subscript 60])W(CO)[subscript 5], form an educational activity for the inorganic chemistry laboratory that promotes graphical thinking as well as the understanding of kinetics, mechanisms, and the…

  7. Displacement Damage Effects in Solar Cells: Mining Damage From the Microelectronics and Photonics Test Bed Space Experiment

    NASA Technical Reports Server (NTRS)

    Hardage, Donna (Technical Monitor); Walters, R. J.; Morton, T. L.; Messenger, S. R.

    2004-01-01

    The objective is to develop an improved space solar cell radiation response analysis capability and to produce a computer modeling tool which implements the analysis. This was accomplished through analysis of solar cell flight data taken on the Microelectronics and Photonics Test Bed experiment. This effort specifically addresses issues related to rapid technological change in the area of solar cells for space applications in order to enhance system performance, decrease risk, and reduce cost for future missions.

  8. Microtomographic quantification of hydraulic clay mineral displacement effects during a CO2 sequestration experiment with saline aquifer sandstone.

    PubMed

    Sell, Kathleen; Enzmann, Frieder; Kersten, Michael; Spangenberg, Erik

    2013-01-01

    We combined a noninvasive tomographic imaging technique with an invasive open-system core-flooding experiment and compared the results of the pre- and postflooded states of an experimental sandstone core sample from an ongoing field trial for carbon dioxide geosequestration. For the experiment, a rock core sample of 80 mL volume was taken from the 629 m Stuttgart Formation storage domain of a saline sandstone aquifer at the CCS research pilot plant Ketzin, Germany. Supercritical carbon dioxide and synthetical brine were injected under in situ reservoir p/T-conditions at an average flow rate of 0.1 mL/min for 256 h. X-ray computed microtomographic imaging was carried out before and after the core-flooding experiment at a spatial voxel resolution of 27 μm. No significant changes in microstructure were found at the tomographic imaging resolution including porosity and pore size distribution, except of an increase of depositional heterogeneous distribution of clay minerals in the pores. The digitized rock data were used as direct real microstructure input to the GeoDict software package, to simulate Navier-Stokes flow by a lattice Boltzmann equation solver. This procedure yielded 3D pressure and flow velocity fields, and revealed that the migration of clay particles decreased the permeability tensor probably due to clogging of pore openings.

  9. Distillation Column Flooding Predictor

    SciTech Connect

    George E. Dzyacky

    2010-11-23

    /vapor traffic that produce increased contact area and lead to substantial increases in separation efficiency – which translates to a 10% increase in energy efficiency on a BTU/bbl basis. The Flooding Predictor™ operates on the principle that between five to sixty minutes in advance of a flooding event, certain column variables experience an oscillation, a pre-flood pattern. The pattern recognition system of the Flooding Predictor™ utilizes the mathematical first derivative of certain column variables to identify the column’s pre-flood pattern(s). This pattern is a very brief, highly repeatable, simultaneous movement among the derivative values of certain column variables. While all column variables experience negligible random noise generated from the natural frequency of the process, subtle pre-flood patterns are revealed among sub-sets of the derivative values of column variables as the column approaches its hydraulic limit. The sub-set of column variables that comprise the pre-flood pattern is identified empirically through in a two-step process. First, 2ndpoint’s proprietary off-line analysis tool is used to mine historical data for pre-flood patterns. Second, the column is flood-tested to fine-tune the pattern recognition for commissioning. Then the Flooding Predictor™ is implemented as closed-loop advanced control strategy on the plant’s distributed control system (DCS), thus automating control of the column at its hydraulic limit.

  10. Design and Preliminary Results of a Feedback Circuit for Plasma Displacement Control in IR-T1 Tokamak

    SciTech Connect

    TalebiTaher, A.; Ghoranneviss, M.; Tarkeshian, R.; Salem, M. K.; Khorshid, P.

    2008-04-07

    Since displacement is very important for plasma position control, in IR-T1 tokamak a combination of two cosine coils and two saddle sine coils is used for horizontal displacement measurement. According to the multiple moment theory, the output of these coils linearly depends to radial displacement of plasma column. A new circuit for adding these signals to feedback system designed and unwanted effects of other fields in final output compensated. After compensation and calibration of the system, the output of horizontal displacement circuits applied to feedback control system. By considers the required auxiliary vertical field, a proportional amplifier and driver circuit are constructed to drive power transistors these power transistors switch the feedback bank capacitors. In the experiment, a good linear proportionality between displacement and output observed by applying an appropriate feedback field, the linger confinement time in IR-T1 tokamak obtained, applying this system to discharge increased the plasma duration and realizes repetitive discharges.

  11. PULSE COLUMN

    DOEpatents

    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)

  12. Lateral displacement and rotational displacement sensor

    DOEpatents

    Duden, Thomas

    2014-04-22

    A position measuring sensor formed from opposing sets of capacitor plates measures both rotational displacement and lateral displacement from the changes in capacitances as overlapping areas of capacitors change. Capacitances are measured by a measuring circuit. The measured capacitances are provided to a calculating circuit that performs calculations to obtain angular and lateral displacement from the capacitances measured by the measuring circuit.

  13. Transport and removal of bacteriophages MS2 and PhiX174 in steel slag-amended soils: column experiments and transport model analyses.

    PubMed

    Park, Jeong-Ann; Kang, Jin-Kyu; Kim, Jae-Hyun; Kim, Song-Bae; Yu, Seungho; Kim, Tae-Hun

    2014-01-01

    The aim of this study was to investigate the removal of bacteriophages MS2 and PhiX174 in soils amended with converter furnace steel slag. Column experiments were performed to examine the bacteriophage removal in slag-amended (slag content: 0%, 25%, and 50%) loam soils. For comparison, column experiments were also conducted with Escherichia coli. In addition, chloride (Cl) was used as a conservative tracer to determine transport characteristics. Results showed mass recoveries of Cl of 98.6 +/- 3.5%, indicating that the experiments were conducted successfully. The mass recovery of MS2 was 86.7% in no slag (100% soil), decreasing to 0% in slag contents of 25% and 50%. The mass recovery of PhiX174 decreased from 87.8% to 51.5% with increasing slag content from 0% to 50%. In the case of E. coli, the mass recoveries decreased from 47.0% to 10.5% with increasing slag content from 0% to 50%. In the transport models analyses, the HYDRUS-1D code was used to quantify the sorption parameters from breakthrough curves. For the 100% soil column, a one-site kinetic sorption model was fitted to the data, whereas a two-site kinetic sorption model was fitted for slag-amended (25% and 50% slag) soil data. Results demonstrate that the addition of steel slag to soil enhances the removal of bacteriophages due to the presence of FeO in the steel slag. However, CaO could not contribute to the bacteriophage removal in our experimental conditions because the effluent pH (7.7-8.9) in slag-amended (25% and 50% slag) soils was not high enough to promote the bacteriophage inactivation.

  14. Thermal - Hydraulic Behavior of Unsaturated Bentonite and Sand-Bentonite Material as Seal for Nuclear Waste Repository: Numerical Simulation of Column Experiments

    NASA Astrophysics Data System (ADS)

    Ballarini, E.; Graupner, B.; Bauer, S.

    2015-12-01

    For deep geological repositories of high-level radioactive waste (HLRW), bentonite and sand bentonite mixtures are investigated as buffer materials to form a a sealing layer. This sealing layer surrounds the canisters and experiences an initial drying due to the heat produced by HLRW and a successive re-saturation with fluid from the host rock. These complex thermal, hydraulic and mechanical processes interact and were investigated in laboratory column experiments using MX-80 clay pellets as well as a mixture of 35% sand and 65% bentonite. The aim of this study is to both understand the individual processes taking place in the buffer materials and to identify the key physical parameters that determine the material behavior under heating and hydrating conditions. For this end, detailed and process-oriented numerical modelling was applied to the experiments, simulating heat transport, multiphase flow and mechanical effects from swelling. For both columns, the same set of parameters was assigned to the experimental set-up (i.e. insulation, heater and hydration system), while the parameters of the buffer material were adapted during model calibration. A good fit between model results and data was achieved for temperature, relative humidity, water intake and swelling pressure, thus explaining the material behavior. The key variables identified by the model are the permeability and relative permeability, the water retention curve and the thermal conductivity of the buffer material. The different hydraulic and thermal behavior of the two buffer materials observed in the laboratory observations was well reproduced by the numerical model.

  15. Investigations on mobility of carbon colloid supported nanoscale zero-valent iron (nZVI) in a column experiment and a laboratory 2D-aquifer test system.

    PubMed

    Busch, Jan; Meißner, Tobias; Potthoff, Annegret; Oswald, Sascha E

    2014-09-01

    Nanoscale zero-valent iron (nZVI) has recently gained great interest in the scientific community as in situ reagent for installation of permeable reactive barriers in aquifer systems, since nZVI is highly reactive with chlorinated compounds and may render them to harmless substances. However, nZVI has a high tendency to agglomerate and sediment; therefore it shows very limited transport ranges. One new approach to overcome the limited transport of nZVI in porous media is using a suited carrier colloid. In this study we tested mobility of a carbon colloid supported nZVI particle "Carbo-Iron Colloids" (CIC) with a mean size of 0.63 μm in a column experiment of 40 cm length and an experiment in a two-dimensional (2D) aquifer test system with dimensions of 110 × 40 × 5 cm. Results show a breakthrough maximum of 82 % of the input concentration in the column experiment and 58 % in the 2D-aquifer test system. Detected residuals in porous media suggest a strong particle deposition in the first centimeters and few depositions in the porous media in the further travel path. Overall, this suggests a high mobility in porous media which might be a significant enhancement compared to bare or polyanionic stabilized nZVI.

  16. Column internals

    SciTech Connect

    Bravo, J.L.

    1998-02-01

    In the fields of distillation, absorption, stripping and extraction, theory and technology go hand in hand. The thermodynamic principles of phase equilibrium and the concepts of mass transfer and fluid flow are of primary importance in all of these operations. The engineer must understand these phenomena to select equipment effectively. This article discusses the latest in commercial technology in column internals for gas-liquid and liquid-liquid contacting. The principles of operation are explained vis-a-vis the characteristics of the applications in which they are used. The focus is on moderate-to-large columns for refining and chemical applications. Guidelines for selecting the most appropriate type of device are presented, and examples of typical applications are described.

  17. Biogeochemical impacts of aquifer thermal energy storage at 5, 12, 25 and 60°C investigated with anoxic column experiments

    NASA Astrophysics Data System (ADS)

    Bonte, M.; van Breukelen, B. M.; Van Der Wielen, P. W. J. J.; Stuyfzand, P. J.

    2012-04-01

    Aquifer thermal energy storage (ATES) uses groundwater to store energy for heating or cooling purposes in the built environment. ATES systems are often located in the same aquifers used for public drinking water supply, leading to urgent questions on its environmental impacts. This contribution presents the results of research on the biogeochemical impacts of ATES in anoxic column experiments at 5, 12, 25, and 60° C. In- and effluents are analyzed for major ions, trace elements, heavy metals, dissolved organic carbon (DOC) and UV extinction. Terminal restriction fragment length polymorphism (T-RFLP) of 16S rRNA genes and analysis of adenosine triphosphate (ATP) were used to detect changes in the microbiological population and activity. Results from the column experiments at 5, 25, and 60° C compared to the reference column at 12° C showed a number of changes in biogeochemical conditions: At 5° C, only changes were observed in alkalinity and calcium concentrations, resulting from calcite dissolution. The 25° C and 60° C column effluents from a sediment containing Fe-(hydr)oxides showed an increase in arsenic concentrations, well above the drinking water limit. This is due to either (reductive) dissolution of, or desorption from, iron(hydro)xides containing arsenic. In addition, at these two temperatures sulfate reduction occurred while this was undetectable at 5 and 12° C within the given timeframe (25 days) and analytical accuracy. The carbon source for sulfate reduction is inferred to be sedimentary organic carbon. Increasing DOC with residence time in the 60° C effluent suggests that at 60° C the terminal sulfate reduction step is rate limiting, while at 25° C the enzymatic hydrolization step in sulfate reducing bacteria is overall rate limiting. Specific ultraviolet absorption (SUVA, the ratio of UV extinction and DOC) however shows a clear decrease in reactivity of the humic acid fraction in DOC. This means that the DOC accumulation at 60° C could

  18. Charge-transfer energy in the water-hydrogen molecular aggregate revealed by molecular-beam scattering experiments, charge displacement analysis, and ab initio calculations.

    PubMed

    Belpassi, Leonardo; Reca, Michael L; Tarantelli, Francesco; Roncaratti, Luiz F; Pirani, Fernando; Cappelletti, David; Faure, Alexandre; Scribano, Yohann

    2010-09-22

    Integral cross-section measurements for the system water-H(2) in molecular-beam scattering experiments are reported. Their analysis demonstrates that the average attractive component of the water-H(2) intermolecular potential in the well region is about 30% stronger than dispersion and induction forces would imply. An extensive and detailed theoretical analysis of the electron charge displacement accompanying the interaction, over several crucial sections of the potential energy surface (PES), shows that water-H(2) interaction is accompanied by charge transfer (CT) and that the observed stabilization energy correlates quantitatively with CT magnitude at all distances. Based on the experimentally determined potential and the calculated CT, a general theoretical model is devised which reproduces very accurately PES sections obtained at the CCSD(T) level with large basis sets. The energy stabilization associated with CT is calculated to be 2.5 eV per electron transferred. Thus, CT is shown to be a significant, strongly stereospecific component of the interaction, with water functioning as electron donor or acceptor in different orientations. The general relevance of these findings for water's chemistry is discussed.

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

    SciTech Connect

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

    1995-09-01

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

  20. Power Law Tailing in Column Air-sparging Experiments and Invasion-percolation Model for Calculating Diffusion Rates in the Liquid Phase.

    NASA Astrophysics Data System (ADS)

    Kawanishi, T.; Ninagawa, K.; Hayashi, Y.

    2006-12-01

    Power law tailings are often seen in removal of pollutants from soil or ground water. We have found that the power law tailing can also be seen in laboratory scale column air-sparging experiments. Researchers so far have found that power law tailings can occur due to the distribution of the micro-pore diffusion rates, or Freundlich type adsorption equilibrium. In addition to that we propose the following hypothesis. Introducing gas to the water saturated glass bead column causes some fractal-like gas flow path, which causes the power law distribution of distance that solute has to travel until it reaches the gas-water interface, this causes the power law tailing. In order to prove this, we constructed a model for removal of solute by diffusion to gas/water interface based on the invasion percolation. In a simple cubic bond lattice, invasion percolation is performed, assuming that the invading phase is gas and remaining phase is water. Then, set the initial concentration in water uniformly unity, set the boundary conditions as the concentration of the solute at the gas/water interfacial nodes is zero. Then diffusion calculation is performed by assuming that in the local scale (in a bond) the diffusion is Fickian. The model successfully reproduced the power law tailings. In the 80x80x80 and 100x100x100 node-lattice, the estimated slope in double-log plots raged from -1.08 to -0.72. The values are different from the normal diffusion in infinite media, -0.50, suggesting that the non-uniform shape of gas/water interface caused this kind of power law tailing. In the column experiments, we found the slope in double-log plots ranging from -0.77 to - 0.54, these values lie mostly between the calculated results and Fickian diffusion, 0.5. This, we consider, is reasonable that the real flow paths should be somewhere between the invading cluster and the straight line.

  1. A Laboratory Experiment To Measure Henry's Law Constants of Volatile Organic Compounds with a Bubble Column and a Gas Chromatography Flame Ionization Detector (GC-FID)

    ERIC Educational Resources Information Center

    Lee, Shan-Hu; Mukherjee, Souptik; Brewer, Brittany; Ryan, Raphael; Yu, Huan; Gangoda, Mahinda

    2013-01-01

    An undergraduate laboratory experiment is described to measure Henry's law constants of organic compounds using a bubble column and gas chromatography flame ionization detector (GC-FID). This experiment is designed for upper-division undergraduate laboratory courses and can be implemented in conjunction with physical chemistry, analytical…

  2. Successfully downsize trayed columns

    SciTech Connect

    Sloley, A.W.; Fleming, B. )

    1994-03-01

    Techniques for the design and sizing of new trayed distillation columns are abundant in the literature. So, too, are the guidelines for modifying towers for operation beyond their original design range. Reducing capacity of distillation trays merits at least as much consideration. Indeed, lack of knowledge and experience in this area causes many tower failures and misdesigned columns. In this article, the authors present some practical design considerations, based on field experience, for tower trays operating at loadings dramatically lower than normal for a particular design. General considerations cover liquid and vapor hydraulics and flow behavior. Case studies are included for there typical units: a refinery vacuum crude still, a petrochemical superfractionator, and a steam stripper.

  3. Micron-Size Zero-Valent Iron Emplacement in Porous Media Using Polymer Additives: Column and Flow Cell Ex-periments

    SciTech Connect

    Oostrom, Mart; Wietsma, Thomas W.; Covert, Matthew A.; Vermeul, Vince R.

    2006-03-20

    At the Hanford Site, an extensive In Situ Redox Manipulation (ISRM) permeable reactive barrier was installed to prevent chromate from reaching the Columbia River. However, chromium has been detected in several wells, indicating a premature loss of the reductive capacity in the aquifer. Laboratory experiments have been conducted to investigate whether barrier reductive capacity can be enhanced by adding micron-scale zero-valent iron to the high-permeability zones within the aquifer using shear-thinning fluids containing polymers. Porous media were packed in a wedge-shaped flow cell to create either a heterogeneous layered system with a high-permeability zone between two low-permeability zones or a high-permeability channel sur-rounded by low-permeability materials. The injection flow rate, polymer type, polymer concentration, and injected pore volumes were determined based on preliminary short- and long-column experiments. The flow cell experiments indicated that iron concentration enhancements of at least 0.6% (w/w) could be obtained using moderate flow rates and injection of 30 pore volumes. The 0.6% amended Fe0 concentration would provide approximately 20 times the average reductive capacity that is provided by the dithionite-reduced iron in the ISRM barrier. Calculations show that a 1-m-long Fe0 amended zone with an average concentration of 0.6% w/w iron subject to a groundwater velocity of 1 m/day will have an estimated longevity of 7.2 years.

  4. Retraining Displaced Workers. Policy Brief

    ERIC Educational Resources Information Center

    LaLonde, Robert; Sullivan, Daniel

    2010-01-01

    Robert LaLonde of the University of Chicago and Daniel Sullivan of the Federal Reserve Bank of Chicago suggest that retraining through our nation's community colleges is a way to reduce the skills gaps of at least some of these displaced workers and increase their reemployment earnings. Although workers may still experience significant earnings…

  5. Monitoring of leaked CO2 through sediment, water column and atmosphere in sub-seabed CCS experiment

    NASA Astrophysics Data System (ADS)

    Shitashima, K.; Sakamoto, A.; Maea, Y.

    2013-12-01

    CO2 capture and storage in sub-seabed geological formations (sub-seabed CCS) is currently being studied as a feasible option to mitigate the accumulation of anthropogenic CO2 in the atmosphere. In implementing sub-seabed CCS, detecting and monitoring the impact of the sequestered CO2 on the ocean environment is highly important. The first controlled CO2 release experiment, entitled 'Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage (QICS)', took place in Ardmucknish Bay, Oban, in May-July 2012. We applied the in-situ pH/pCO2/ORP sensor to the QICS experiment for detection and monitoring of leaked CO2, and carried out several observations. The on-line sensor that was connected by 400m of RS422 cable was deployed close to the CO2 leakage (bubbling) point, and the fluctuations of pH, pCO2 and ORP were monitored in real-time in a observation van on land. Three sets of off-line sensors were also placed on seafloor in respective points (release point, and two low impacted regions at 25m and 75m distant) for three months. The long-term monitoring of pH in sediment at 50cm depth under the seafloor was conducted. The spear type electrode was stabbed into sediment by diver near the CO2 leakage point. Wide-area mapping surveys of pH, pCO2 and ORP in seawater around the leakage point were carried out by AUV (REMUS-100) that some chemical sensors were installed in. The AUV cruised along the grid line in two layers of 4m and 2m above the seafloor during both of periods of low tide and high tide. Atmospheric CO2 in sea surface above the leakage point was observed by the LI-COR CO2 Analyzer. The analyzer was attached to the bow of ship, and the ship navigated a wide-area along a grid observation line during both of periods of low tide and high tide.

  6. Permeability changes during remediation of an aquifer affected by sea-water intrusion: A laboratory column study

    NASA Astrophysics Data System (ADS)

    Zhou, Jun; Zheng, Xilai; Flury, Markus; Lin, Guoqing

    2009-10-01

    SummaryDuring flushing of a seawater-affected aquifer with freshwater, fine particles can be mobilized and can subsequently clog up pores, thereby causing a reduction of permeability. Here, we used packed columns (25 cm length) to experimentally investigate the changes in permeability during such a remediation scenario. We hypothesized that a gradual and abrupt change in salinity, as well as the pressure boundary conditions along the column, will affect the particle release and permeability changes. We collected sediments from a coastal aquifer in China, in which seawater had intruded. The sediments were packed into laboratory columns. The columns were oriented horizontally and instrumented with a series of piezometers to measure hydraulic heads along the column. Several sequences of displacements of seawater (electrical conductivity (EC) 48.5 mS/cm) with freshwater (EC 0.78 mS/cm) were passed through the columns. Permeability was determined from measured flow rates and hydraulic heads. Experiments were conducted both with constant head as well as with constant flux conditions. Column outflow was analyzed for suspended particles and electrical conductivity. The results indicate that the permeability was reduced by up to 70% when seawater was displaced with freshwater. Under constant head conditions, permeability reductions were more pronounced than under constant flux. The critical salinity (i.e., electrical conductivity associated with the critical salt concentration) for particle release in the sediments was 7 mS/cm. When salinity was changed abruptly, fine particles were eluted from the column; however, when the salinity change was gradual, no fines were eluted. In agreement with previous literature data, we observed a more pronounced reduction of permeability under an abrupt than under a gradual salinity change. Permeability reduction was not uniform along the column, with generally decreasing permeability with increasing distance from the column inlet.

  7. Heavy metal displacement in chelate-irrigated soil during phytoremediation

    NASA Astrophysics Data System (ADS)

    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.

  8. Spectral Signature of Column Solar Radiation Absorption During the Atmospheric Radiation Measurement Enhanced Shortwave Experiment (ARESE). Revision

    SciTech Connect

    O'Hirok, William; Gautier, Catherine; Ricchiazzi, Paul

    1999-11-01

    Spectral and broadband shortwave radiative flux data obtained from the Atmospheric Radiation Measurement Enhanced Shortwave Experiment (ARESE) are compared with 3-D radiative transfer computations for the cloud field of October 30, 1995. Because the absorption of broadband solar radiation in the cloudy atmosphere deduced from observations and modeled differ by 135 Wm{sup -2}, we performed a consistency analysis using spectral observations and the model to integrate for wavelengths between the spectral observations. To match spectral measurements, aerosols need a reduction in both single scattering albedo (from 0.938 to 0.82) and asymmetry factor (from 0.67 to 0.61), and cloud droplets require a three-fold increase in co-albedo. Even after modifying the model inputs and microphysics the difference in total broadband absorption is still of the order of 75Wm{sup -2}. Finally, an unexplained absorber centered around 1.06 {micro}m appears in the comparison that is much too large to be explained by dimers.

  9. The specific reactive surface area of granular zero-valent iron in metal contaminant removal: Column experiments and modelling.

    PubMed

    Statham, Tom M; Mason, Lachlan R; Mumford, Kathryn A; Stevens, Geoffrey W

    2015-06-15

    A series of dynamic-flow kinetic experiments were conducted to assess the removal rates of aqueous Cu(2+) and Zn(2+) ions by zero-valent iron (ZVI), a promising material for inclusion in cold-climate remediation applications. The influence of experimental parameters on contaminant removal rates, including aqueous flow rate, operating temperature, and the concentrations of ZVI, salt and dissolved oxygen, was investigated. A mass transport model has been developed that accounts (i) aqueous-phase dispersion processes, (ii) film diffusion of contaminant ions to the reactive ZVI surface and (iii) the reactive removal mechanism itself. Regression to the experimental data indicated that when oxygen is present in the solution feed Cu(2+) and Zn(2+) removal processes were limited by film diffusion. In de-aerated solutions film diffusion still controls Cu(2+) removal but a first-order surface reaction provides a better model for Zn(2+) kinetics. Using air as the equilibrium feed gas, the reactive proportion of the total surface area for contaminant removal was calculated to be 97% and 64% of the active spherically-assumed geometric area associated with ZVI media for Cu(2+) and Zn(2+), respectively. Relative to a gas absorption area, determined in previous studies, the reactive proportion is less than 0.41% of the unreacted ZVI total surface area. These findings suggest that only part of the iron oxyhydroxide surface is reacting during ZVI based metal contaminant removal. PMID:25839833

  10. The specific reactive surface area of granular zero-valent iron in metal contaminant removal: Column experiments and modelling.

    PubMed

    Statham, Tom M; Mason, Lachlan R; Mumford, Kathryn A; Stevens, Geoffrey W

    2015-06-15

    A series of dynamic-flow kinetic experiments were conducted to assess the removal rates of aqueous Cu(2+) and Zn(2+) ions by zero-valent iron (ZVI), a promising material for inclusion in cold-climate remediation applications. The influence of experimental parameters on contaminant removal rates, including aqueous flow rate, operating temperature, and the concentrations of ZVI, salt and dissolved oxygen, was investigated. A mass transport model has been developed that accounts (i) aqueous-phase dispersion processes, (ii) film diffusion of contaminant ions to the reactive ZVI surface and (iii) the reactive removal mechanism itself. Regression to the experimental data indicated that when oxygen is present in the solution feed Cu(2+) and Zn(2+) removal processes were limited by film diffusion. In de-aerated solutions film diffusion still controls Cu(2+) removal but a first-order surface reaction provides a better model for Zn(2+) kinetics. Using air as the equilibrium feed gas, the reactive proportion of the total surface area for contaminant removal was calculated to be 97% and 64% of the active spherically-assumed geometric area associated with ZVI media for Cu(2+) and Zn(2+), respectively. Relative to a gas absorption area, determined in previous studies, the reactive proportion is less than 0.41% of the unreacted ZVI total surface area. These findings suggest that only part of the iron oxyhydroxide surface is reacting during ZVI based metal contaminant removal.

  11. Developing large-scale forcing data for single-column and cloud-resolving models from the Mixed-Phase Arctic Cloud Experiment

    DOE PAGESBeta

    Xie, Shaocheng; Klein, Stephen A.; Zhang, Minghua; Yio, John J.; Cederwall, Richard T.; McCoy, Renata

    2006-10-05

    [1] This study represents an effort to develop Single-Column Model (SCM) and Cloud-Resolving Model large-scale forcing data from a sounding array in the high latitudes. An objective variational analysis approach is used to process data collected from the Atmospheric Radiation Measurement Program (ARM) Mixed-Phase Arctic Cloud Experiment (M-PACE), which was conducted over the North Slope of Alaska in October 2004. In this method the observed surface and top of atmosphere measurements are used as constraints to adjust the sounding data from M-PACE in order to conserve column-integrated mass, heat, moisture, and momentum. Several important technical and scientific issues related tomore » the data analysis are discussed. It is shown that the analyzed data reasonably describe the dynamic and thermodynamic features of the Arctic cloud systems observed during M-PACE. Uncertainties in the analyzed forcing fields are roughly estimated by examining the sensitivity of those fields to uncertainties in the upper-air data and surface constraints that are used in the analysis. Impacts of the uncertainties in the analyzed forcing data on SCM simulations are discussed. Results from the SCM tests indicate that the bulk features of the observed Arctic cloud systems can be captured qualitatively well using the forcing data derived in this study, and major model errors can be detected despite the uncertainties that exist in the forcing data as illustrated by the sensitivity tests. Lastly, the possibility of using the European Center for Medium-Range Weather Forecasts analysis data to derive the large-scale forcing over the Arctic region is explored.« less

  12. Developing large-scale forcing data for single-column and cloud-resolving models from the Mixed-Phase Arctic Cloud Experiment

    SciTech Connect

    Xie, Shaocheng; Klein, Stephen A.; Zhang, Minghua; Yio, John J.; Cederwall, Richard T.; McCoy, Renata

    2006-10-05

    [1] This study represents an effort to develop Single-Column Model (SCM) and Cloud-Resolving Model large-scale forcing data from a sounding array in the high latitudes. An objective variational analysis approach is used to process data collected from the Atmospheric Radiation Measurement Program (ARM) Mixed-Phase Arctic Cloud Experiment (M-PACE), which was conducted over the North Slope of Alaska in October 2004. In this method the observed surface and top of atmosphere measurements are used as constraints to adjust the sounding data from M-PACE in order to conserve column-integrated mass, heat, moisture, and momentum. Several important technical and scientific issues related to the data analysis are discussed. It is shown that the analyzed data reasonably describe the dynamic and thermodynamic features of the Arctic cloud systems observed during M-PACE. Uncertainties in the analyzed forcing fields are roughly estimated by examining the sensitivity of those fields to uncertainties in the upper-air data and surface constraints that are used in the analysis. Impacts of the uncertainties in the analyzed forcing data on SCM simulations are discussed. Results from the SCM tests indicate that the bulk features of the observed Arctic cloud systems can be captured qualitatively well using the forcing data derived in this study, and major model errors can be detected despite the uncertainties that exist in the forcing data as illustrated by the sensitivity tests. Lastly, the possibility of using the European Center for Medium-Range Weather Forecasts analysis data to derive the large-scale forcing over the Arctic region is explored.

  13. The effect of salinization and freshening events in coastal aquifers on nutrient characteristics as deduced from column experiments under aerobic and anaerobic conditions

    NASA Astrophysics Data System (ADS)

    Russak, A.; Sivan, O.; Herut, B.; Lazar, B.; Yechieli, Y.

    2015-10-01

    This study experimentally quantified the effect of seawater intrusion (salinization) and freshening events in coastal aquifers on nutrient (N, P and DSi) dynamics across the fresh-saline groundwater interface. Laboratory column experiments were conducted under aerobic and anaerobic conditions in order to simulate the processes occurring in the fresh-saline interface. They were performed with aquifer sediments, simulating the natural conditions during alterations of natural fresh groundwater to seawater and vice versa. The salinization and freshening experiments showed that NH4+ and PO43- and DSi were affected mainly by ion exchange processes while microbial activity controlled the nitrogen species NO3- and NO2-. Due to the cation exchange, salinization generated enrichment (above the expected conservative behavior) of NH4+, up to 80 μmol L-1 (an order of magnitude higher than in seawater or fresh groundwater). Under anaerobic conditions NO3- was removed by denitrification, as demonstrated by the decrease in NO3- concentrations, the increase in NO2- concentrations, and the increase in δ15N by 15-25‰. Clear evidence was shown for anion exchange of PO43-, which competes with HCO3- and boron on adsorption sites. DSi seems to take part in the exchange process, similar to PO43-.

  14. A new physical model based on cascading column experiments to reproduce the radial flow and transport of micro-iron particles.

    PubMed

    Comba, Silvia; Braun, Jürgen

    2012-10-01

    In the field of aquifer restoration and civil engineering, fluids and suspensions are delivered in porous media via well injection. The flow field resulting around the well is three-dimensional. Since two and three-dimensional experiments which can be used to reproduce such flow fields are, although accurate, extremely elaborate and time consuming, the authors suggest to substitute them by a cascade of interdependent, one-dimensional (column) experiments. The new method is used to simulate the injection in aquifers of micro-iron particles dispersed in a shear thinning gel of guar gum and allows the prediction of iron particle distribution around the well and of injection pressure. The method respects the mass balance at the field scale and its predictions are in good agreement with those of a mathematical model proposed in the literature. The method is consistent with the Triad Approach, a way to improve remediation efficiency proposed by the U.S. Environmental Protection Agency. The representativeness of the proposed tests combined with their simplicity and relative inexpensiveness make this new method applicable and useful in the planning and design of real remediation.

  15. A new physical model based on cascading column experiments to reproduce the radial flow and transport of micro-iron particles

    NASA Astrophysics Data System (ADS)

    Comba, Silvia; Braun, Jürgen

    2012-10-01

    In the field of aquifer restoration and civil engineering, fluids and suspensions are delivered in porous media via well injection. The flow field resulting around the well is three-dimensional. Since two and three-dimensional experiments which can be used to reproduce such flow fields are, although accurate, extremely elaborate and time consuming, the authors suggest to substitute them by a cascade of interdependent, one-dimensional (column) experiments. The new method is used to simulate the injection in aquifers of micro-iron particles dispersed in a shear thinning gel of guar gum and allows the prediction of iron particle distribution around the well and of injection pressure. The method respects the mass balance at the field scale and its predictions are in good agreement with those of a mathematical model proposed in the literature. The method is consistent with the Triad Approach, a way to improve remediation efficiency proposed by the U.S. Environmental Protection Agency. The representativeness of the proposed tests combined with their simplicity and relative inexpensiveness make this new method applicable and useful in the planning and design of real remediation.

  16. Experimenting with a Visible Copper-Aluminum Displacement Reaction in Agar Gel and Observing Copper Crystal Growth Patterns to Engage Student Interest and Inquiry

    ERIC Educational Resources Information Center

    Xu, Xinhua; Wu, Meifen; Wang, Xiaogang; Yang, Yangyiwei; Shi, Xiang; Wang, Guoping

    2016-01-01

    The reaction process of copper-aluminum displacement in agar gel was observed at the microscopic level with a stereomicroscope; pine-like branches of copper crystals growing from aluminum surface into gel at a constant rate were observed. Students were asked to make hypotheses on the pattern formation and design new research approaches to prove…

  17. Displacement of Propagating Squeezed Microwave States

    NASA Astrophysics Data System (ADS)

    Fedorov, Kirill G.; Zhong, L.; Pogorzalek, S.; Eder, P.; Fischer, M.; Goetz, J.; Xie, E.; Wulschner, F.; Inomata, K.; Yamamoto, T.; Nakamura, Y.; Di Candia, R.; Las Heras, U.; Sanz, M.; Solano, E.; Menzel, E. P.; Deppe, F.; Marx, A.; Gross, R.

    2016-07-01

    Displacement of propagating quantum states of light is a fundamental operation for quantum communication. It enables fundamental studies on macroscopic quantum coherence and plays an important role in quantum teleportation protocols with continuous variables. In our experiments, we have successfully implemented this operation for propagating squeezed microwave states. We demonstrate that, even for strong displacement amplitudes, there is no degradation of the squeezing level in the reconstructed quantum states. Furthermore, we confirm that path entanglement generated by using displaced squeezed states remains constant over a wide range of the displacement power.

  18. Displacement of Propagating Squeezed Microwave States.

    PubMed

    Fedorov, Kirill G; Zhong, L; Pogorzalek, S; Eder, P; Fischer, M; Goetz, J; Xie, E; Wulschner, F; Inomata, K; Yamamoto, T; Nakamura, Y; Di Candia, R; Las Heras, U; Sanz, M; Solano, E; Menzel, E P; Deppe, F; Marx, A; Gross, R

    2016-07-01

    Displacement of propagating quantum states of light is a fundamental operation for quantum communication. It enables fundamental studies on macroscopic quantum coherence and plays an important role in quantum teleportation protocols with continuous variables. In our experiments, we have successfully implemented this operation for propagating squeezed microwave states. We demonstrate that, even for strong displacement amplitudes, there is no degradation of the squeezing level in the reconstructed quantum states. Furthermore, we confirm that path entanglement generated by using displaced squeezed states remains constant over a wide range of the displacement power. PMID:27447495

  19. Displacement of Propagating Squeezed Microwave States.

    PubMed

    Fedorov, Kirill G; Zhong, L; Pogorzalek, S; Eder, P; Fischer, M; Goetz, J; Xie, E; Wulschner, F; Inomata, K; Yamamoto, T; Nakamura, Y; Di Candia, R; Las Heras, U; Sanz, M; Solano, E; Menzel, E P; Deppe, F; Marx, A; Gross, R

    2016-07-01

    Displacement of propagating quantum states of light is a fundamental operation for quantum communication. It enables fundamental studies on macroscopic quantum coherence and plays an important role in quantum teleportation protocols with continuous variables. In our experiments, we have successfully implemented this operation for propagating squeezed microwave states. We demonstrate that, even for strong displacement amplitudes, there is no degradation of the squeezing level in the reconstructed quantum states. Furthermore, we confirm that path entanglement generated by using displaced squeezed states remains constant over a wide range of the displacement power.

  20. Precision displacement reference system

    DOEpatents

    Bieg, Lothar F.; Dubois, Robert R.; Strother, Jerry D.

    2000-02-22

    A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

  1. Fate and transport of carbamazepine in a soil aquifer treatment (SAT) system: evaluation of a monitoring study and soil column experiments

    NASA Astrophysics Data System (ADS)

    Arye, G.; Dror, I.; Berkowitz, B.

    2009-12-01

    Carbamazepine (CBZ), an anticonvulsant and mood stabilizing drug, is found to be highly persistent in wastewater treatment plants and when subsequently released to the environment. Because of its physicochemical properties, CBZ is only weakly sorbed to mineral soils and is resistant to biodegradation. As a consequence, CBZ has been suggested as an appropriate anthropogenic marker to track the fate of wastewater in aquatic systems. We study the fate and transport of CBZ in the Dan Region Reclamation Project (Shafdan) in Israel, where about one quarter of the country’s wastewater undergoes purification. The secondary treatment of raw wastewater consists of mechanical and biological treatment by activated sludge, with an additional step of nitrification-denitrification, and subsequent recharge of treated effluent to groundwater via infiltration basins, as a complementary tertiary treatment known as soil aquifer treatment (SAT). Water produced from the SAT system is pumped from a depth of 100-200 m by means of approximately 100 recovery wells, located 300-1,500 m from the recharge basins. This water is then delivered through a single 87 km long pipeline to the southern part of the country, where it is used for irrigation. We examine the fate of CBZ before and after treatment with the SAT system. To date, our monitoring has detected up to 1300 ng/L of CBZ in the recharged effluent before SAT, and up to 700 ng/L after treatment, prior to use for irrigation. The latter may considered as an aggregate value from all recovery wells. Additional information on CBZ transport characteristics has been gained from a series of soil column experiments using soil samples taken from the SAT infiltration basin to a depth of 170 cm. For each soil layer examined, the soil column was first leached of CBZ and subsequently loaded with secondary treated wastewater containing CBZ. The CBZ breakthrough curves resemble transport of a conservative tracer in most of the soil samples. We

  2. A Column Experiment To Determine Black Shale Degradation And Colonization By Means of δ13C and 14C Analysis Of Phospholipid Fatty Acids And DNA Extraction

    NASA Astrophysics Data System (ADS)

    Seifert, A.; Gleixner, G.

    2008-12-01

    We investigated the degradation of black shale organic matter by microbial communities. We inoculated two columns respectively, with the fungi Schizophyllum commune, the gram-positive bacterium Pseudomonas putida and the gram-negative bacteria Streptomyces griseus and Streptomyces chartreusis. These microorganisms are known to degrade a wide variety of organic macromolecules. Additionally, we had two sets of control columns. To one set the same nutrient solution was added as to the inoculated columns and to the other set only sterile deionised water was supplied. All columns contained 1.5 kg of freshly crushed not autoclaved black shale material with a particle size of 0.63-2 mm. The columns were incubated at 28° C and 60% humidity in the dark. The aim was to investigate, which microorganisms live on black shales and if these microorganisms are able to degrade ancient organic matter. We used compound specific stable isotope measurement techniques and compound specific 14C-dating methods. After 183 days PLFAs were extracted from the columns to investigate the microbial community, furthermore we extracted on one hand total-DNA of column material and on the other hand DNA from pure cultures isolates which grew on Kinks-agar B, Starch-casein-nitrate-agar (SCN) and on complete-yeast-medium-agar (CYM). According to the PLFA analysis bacteria dominated in the columns, whereas in pure cultures more fungi were isolated. A principal component analysis revealed differences between the columns in accordance with the inoculation, but it seems that the inoculated microorganisms were replaced by the natural population. For AMS measurements palmitic acid (C 16:0) was re-isolated from total-PLFA-extract with a preparative fraction collector (PFC). Preliminary results of the study revealed that microorganisms are able to degrade black shale material and that PLFA analysis are useful methods to be combined with analysis of stable isotope and 14C measurements to study microbial

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

    PubMed

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

    2015-08-19

    Post Column derivatisation (PCD) coupled with high performance liquid chromatography or ultra-high performance liquid chromatography is a powerful tool in the modern analytical laboratory, or at least it should be. One drawback with PCD techniques is the extra post-column dead volume due to reaction coils used to enable adequate reaction time and the mixing of reagents which causes peak broadening, hence a loss of separation power. This loss of efficiency is counter-productive to modern HPLC technologies, -such as UHPLC. We reviewed 87 PCD methods published from 2009 to 2014. We restricted our review to methods published between 2009 and 2014, because we were interested in the uptake of PCD methods in UHPLC environments. Our review focused on a range of system parameters including: column dimensions, stationary phase and particle size, as well as the geometry of the reaction loop. The most commonly used column in the methods investigated was not in fact a modern UHPLC version with sub-2-micron, (or even sub-3-micron) particles, but rather, work-house columns, such as, 250 × 4.6 mm i.d. columns packed with 5 μm C18 particles. Reaction loops were varied, even within the same type of analysis, but the majority of methods employed loop systems with volumes greater than 500 μL. A second part of this review illustrated briefly the effect of dead volume on column performance. The experiment evaluated the change in resolution and separation efficiency of some weak to moderately retained solutes on a 250 × 4.6 mm i.d. column packed with 5 μm particles. The data showed that reaction loops beyond 100 μL resulted in a very serious loss of performance. Our study concluded that practitioners of PCD methods largely avoid the use of UHPLC-type column formats, so yes, very much, PCD is incompatible with the modern HPLC column. PMID:26343427

  4. Applying reactive models to column experiments to assess the hydrogeochemistry of seawater intrusion: Optimising ACUAINTRUSION and selecting cation exchange coefficients with PHREEQC

    NASA Astrophysics Data System (ADS)

    Boluda-Botella, N.; Valdes-Abellan, J.; Pedraza, R.

    2014-03-01

    Three sets of laboratory column experimental results concerning the hydrogeochemistry of seawater intrusion have been modelled using two codes: ACUAINTRUSION (Chemical Engineering Department, University of Alicante) and PHREEQC (U.S.G.S.). These reactive models utilise the hydrodynamic parameters determined using the ACUAINTRUSION TRANSPORT software and fit the chloride breakthrough curves perfectly. The ACUAINTRUSION code was improved, and the instabilities were studied relative to the discretisation. The relative square errors were obtained using different combinations of the spatial and temporal steps: the global error for the total experimental data and the partial error for each element. Good simulations for the three experiments were obtained using the ACUAINTRUSION software with slight variations in the selectivity coefficients for both sediments determined in batch experiments with fresh water. The cation exchange parameters included in ACUAINTRUSION are those reported by the Gapon convention with modified exponents for the Ca/Mg exchange. PHREEQC simulations performed using the Gains-Thomas convention were unsatisfactory, with the exchange coefficients from the database of PHREEQC (or range), but those determined with fresh water - natural sediment allowed only an approximation to be obtained. For the treated sediment, the adjusted exchange coefficients were determined to improve the simulation and are vastly different from those from the database of PHREEQC or batch experiment values; however, these values fall in an order similar to the others determined under dynamic conditions. Different cation concentrations were simulated using two different software packages; this disparity could be attributed to the defined selectivity coefficients that affect the gypsum equilibrium. Consequently, different calculated sulphate concentrations are obtained using each type of software; a smaller mismatch was predicted using ACUAINTRUSION. In general, the presented

  5. A large column analog experiment of stable isotope variations during reactive transport: II. Carbon mass balance, microbial community structure and predation

    NASA Astrophysics Data System (ADS)

    Druhan, Jennifer L.; Bill, Markus; Lim, HsiaoChien; Wu, Cindy; Conrad, Mark E.; Williams, Kenneth H.; DePaolo, Donald J.; Brodie, Eoin L.

    2014-01-01

    Here we report a combined analysis of carbon mass balance based on isotopic labeling and microbiological characterization during organic carbon stimulated bioreduction of a subsurface sediment in a large laboratory column experimental system. This combination of approaches allows quantification of both the cycling of carbon through multiple redox pathways and the associated spatial and temporal evolution of bacterial communities in response to this nutrient source. Carbon isotope mass balance facilitated by the use of 13C-labeled acetate as the electron donor showed evidence for a net loss of sediment organic carbon over the course of the amendment experiment. Furthermore, these data clearly demonstrated a source of isotopically labeled inorganic carbon that was not attributable to primary metabolism by acetate-oxidizing microorganisms. Fluid samples collected weekly over the duration of the 43-day amendment at <20 cm intervals along the flow path were analyzed for microbial composition by pyrosequencing of ribosomal RNA genes. The microbial community composition was transient, with distinct occurrences of Azoarcus, Geobacter and multiple sulfate reducing species over the course of the experiment. In combination with DNA sequencing data, the anomalous carbon cycling process is shown to occur exclusively during the period of predominant Geobacter species growth. Pyrosequencing indicated, and targeted cloning and sequencing confirmed the presence of several bacteriovorous protozoa, including species of the Breviata, Planococcus and Euplotes genera. Cloning and qPCR analysis demonstrated that Euplotes species were most abundant and displayed a growth trajectory that closely followed that of the Geobacter population. These results suggest a previously undocumented secondary turnover of biomass carbon related to protozoan grazing that was not sufficiently prevalent to be observed in bulk concentrations of carbon species in the system, but was clearly identified in the

  6. Microbial Consortia Development and Microcosm and Column Experiments for Enhanced Bioremediation of Chlorinated Volatile Organic Compounds, West Branch Canal Creek Wetland Area, Aberdeen Proving Ground, Maryland

    USGS Publications Warehouse

    Lorah, Michelle M.; Majcher, Emily H.; Jones, Elizabeth J.; Voytek, Mary A.

    2008-01-01

    Chlorinated solvents, including 1,1,2,2-tetrachloroethane, tetrachloroethene, trichloroethene, carbon tetrachloride, and chloroform, are reaching land surface in localized areas of focused ground-water discharge (seeps) in a wetland and tidal creek in the West Branch Canal Creek area, Aberdeen Proving Ground, Maryland. In cooperation with the U.S. Army Garrison, Aberdeen Proving Ground, Maryland, the U.S. Geological Survey is developing enhanced bioremediation methods that simulate the natural anaerobic degradation that occurs without intervention in non-seep areas of the wetland. A combination of natural attenuation and enhanced bioremediation could provide a remedy for the discharging ground-water plumes that would minimize disturbance to the sensitive wetland ecosystem. Biostimulation (addition of organic substrate or nutrients) and bioaugmentation (addition of microbial consortium), applied either by direct injection at depth in the wetland sediments or by construction of a permeable reactive mat at the seep surface, were tested as possible methods to enhance anaerobic degradation in the seep areas. For the first phase of developing enhanced bioremediation methods for the contaminant mixtures in the seeps, laboratory studies were conducted to develop a microbial consortium to degrade 1,1,2,2-tetrachloroethane and its chlorinated daughter products under anaerobic conditions, and to test biostimulation and bioaugmentation of wetland sediment and reactive mat matrices in microcosms. The individual components required for the direct injection and reactive mat methods were then combined in column experiments to test them under groundwater- flow rates and contaminant concentrations observed in the field. Results showed that both direct injection and the reactive mat are promising remediation methods, although the success of direct injection likely would depend on adequately distributing and maintaining organic substrate throughout the wetland sediment in the seep

  7. 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.

    PubMed

    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.

  8. Computer simulation of displacement cation exchange chromatography: separation of trivalent actinides and lanthanides

    SciTech Connect

    Forsberg, C.W.

    1980-05-01

    A first-generation mathematical model of displacement cation exchange chromatography (CES) was constructed. The model incorporated the following phenomena: diffusion of cations up and down the column, diffusion of cations from the bulk liquid to the resin surface, and equilibrium of cations between liquid and solid resin beads. A limited number of experiments with rare earths using DTPA as the separation agent were undertaken to increase the current understanding of the processes involved in cation exchange chromatography. The numerical computer program based on the mathematical model was written in FORTRAN IV for use on the IBM 360 series of computers.

  9. Advanced Triangulation Displacement Sensors

    NASA Technical Reports Server (NTRS)

    Poteet, Wade M.; Cauthen, Harold K.

    1996-01-01

    Advanced optoelectronic triangulation displacement sensors undergoing development. Highly miniaturized, more stable, more accurate, and relatively easy to use. Incorporate wideband electronic circuits suitable for real-time monitoring and control of displacements. Measurements expected to be accurate to within nanometers. In principle, sensors mass-produced at relatively low unit cost. Potential applications numerous. Possible industrial application in measuring runout of rotating shaft or other moving part during fabrication in "zero-defect" manufacturing system, in which measured runout automatically corrected.

  10. Implications of Research on Displaced Workers. ERIC Digest No. 80.

    ERIC Educational Resources Information Center

    Naylor, Michele

    Worker displacement is more closely related to structural features associated with firms than to the characteristics of the individuals who lost their jobs. Despite economic growth, large numbers of displaced workers continue to experience difficulty in making labor market adjustments. Programs to retrain and reemploy displaced workers exist at…

  11. Internal displacement in Burma.

    PubMed

    Lanjouw, S; Mortimer, G; Bamforth, V

    2000-09-01

    The internal displacement of populations in Burma is not a new phenomenon. Displacement is caused by numerous factors. Not all of it is due to outright violence, but much is a consequence of misguided social and economic development initiatives. Efforts to consolidate the state by assimilating populations in government-controlled areas by military authorities on the one hand, while brokering cease-fires with non-state actors on the other, has uprooted civilian populations throughout the country. Very few areas in which internally displaced persons (IDPs) are found are not facing social turmoil within a climate of impunity. Humanitarian access to IDP populations remains extremely problematic. While relatively little information has been collected, assistance has been focused on targeting accessible groups. International concern within Burma has couched the problems of displacement within general development modalities, while international attention along its borders has sought to contain displacement. With the exception of several recent initiatives, few approaches have gone beyond assistance and engaged in the prevention or protection of the displaced.

  12. Effects of kaolinite colloids on Cd2 + transport through saturated sand under varying ionic strength conditions: Column experiments and modeling approaches

    NASA Astrophysics Data System (ADS)

    Wikiniyadhanee, Rakkreat; Chotpantarat, Srilert; Ong, Say Kee

    2015-11-01

    Column experiments were performed under various ionic strengths (0.0-0.9 mM) using 10 mg L- 1 of Cd2 + without kaolinite colloids and 10 mg L- 1 Cd2 + mixed with 100 mg L- 1 kaolinite colloids. The nonequilibrium two-site model (TSM) described the behavior of both Cd2 + transport and Cd2 + co-transported with kaolinite colloids better than the equilibrium model (CDeq) (R2 = 0.978-0.996). The results showed that an increase in ionic strength negatively impacted the retardation factors (R) of both Cd2 + and Cd2 + mixed with kaolinite colloids. The presence of kaolinite colloids increased the retardation factors of Cd2 + from 7.23 to 7.89, 6.76 to 6.61 and 3.79 to 6.99 for ionic strengths of 0.225, 0.45 and 0.9 mM, respectively. On the other hand, the presence of kaolinite colloids decreased the retardation factor of Cd2 + from 8.13 to 7.83 for ionic strength of 0.0 mM. The fraction of instantaneous sorption sites (f) parameters, kinetic constant for sorption sites (α) and Freundlich constant (Kf) were estimated from HYDRUS-1D of TSM for Cd2 + transport. The fraction of instantaneous sorption sites was found to increase for an increase in ionic strength. Kf values of Cd2 + transport without kaolinite colloids for 0.0, 0.225 and 0.45 mM were found to be higher than those of Cd2 + transport with kaolinite colloids, except for ionic strength of 0.9 mM. Hence, the presence of kaolinite colloids probably retarded the mobility of Cd2 + in porous media for higher ionic strengths. Furthermore, retardation factors and Kf values of both Cd2 + transport and Cd2 + co-transport were shown to decrease when ionic strength increased. Interestingly, according to TSM, the fraction of instantaneous sorption sites tends to increase for an increase in ionic strength, which imply that the mechanism of Cd2 + sorption onto quartz sand can be better described using equilibrium sorption rather than nonequilibrium sorption for an increase in ionic strength.

  13. Effects of kaolinite colloids on Cd²⁺ transport through saturated sand under varying ionic strength conditions: Column experiments and modeling approaches.

    PubMed

    Wikiniyadhanee, Rakkreat; Chotpantarat, Srilert; Ong, Say Kee

    2015-11-01

    Column experiments were performed under various ionic strengths (0.0-0.9 mM) using 10 mg L(-1) of Cd(2+) without kaolinite colloids and 10 mg L(-1) Cd(2+) mixed with 100 mg L(-1) kaolinite colloids. The nonequilibrium two-site model (TSM) described the behavior of both Cd(2+) transport and Cd(2+) co-transported with kaolinite colloids better than the equilibrium model (CD(eq)) (R(2)=0.978-0.996). The results showed that an increase in ionic strength negatively impacted the retardation factors (R) of both Cd(2+) and Cd(2+) mixed with kaolinite colloids. The presence of kaolinite colloids increased the retardation factors of Cd(2+) from 7.23 to 7.89, 6.76 to 6.61 and 3.79 to 6.99 for ionic strengths of 0.225, 0.45 and 0.9 mM, respectively. On the other hand, the presence of kaolinite colloids decreased the retardation factor of Cd(2+) from 8.13 to 7.83 for ionic strength of 0.0 mM. The fraction of instantaneous sorption sites (f) parameters, kinetic constant for sorption sites (α) and Freundlich constant (K(f)) were estimated from HYDRUS-1D of TSM for Cd(2+) transport. The fraction of instantaneous sorption sites was found to increase for an increase in ionic strength. K(f) values of Cd(2+) transport without kaolinite colloids for 0.0, 0.225 and 0.45 mM were found to be higher than those of Cd(2+) transport with kaolinite colloids, except for ionic strength of 0.9 mM. Hence, the presence of kaolinite colloids probably retarded the mobility of Cd(2+) in porous media for higher ionic strengths. Furthermore, retardation factors and K(f) values of both Cd(2+) transport and Cd(2+) co-transport were shown to decrease when ionic strength increased. Interestingly, according to TSM, the fraction of instantaneous sorption sites tends to increase for an increase in ionic strength, which imply that the mechanism of Cd(2+) sorption onto quartz sand can be better described using equilibrium sorption rather than nonequilibrium sorption for an increase in ionic strength.

  14. Column Liquid Chromatography.

    ERIC Educational Resources Information Center

    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,…

  15. Water displacement mercury pump

    DOEpatents

    Nielsen, M.G.

    1984-04-20

    A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

  16. Water displacement mercury pump

    DOEpatents

    Nielsen, Marshall G.

    1985-01-01

    A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

  17. Optical displacement sensor

    DOEpatents

    Carr, Dustin W.

    2008-04-08

    An optical displacement sensor is disclosed which uses a vertical-cavity surface-emitting laser (VCSEL) coupled to an optical cavity formed by a moveable membrane and an output mirror of the VCSEL. This arrangement renders the lasing characteristics of the VCSEL sensitive to any movement of the membrane produced by sound, vibrations, pressure changes, acceleration, etc. Some embodiments of the optical displacement sensor can further include a light-reflective diffractive lens located on the membrane or adjacent to the VCSEL to control the amount of lasing light coupled back into the VCSEL. A photodetector detects a portion of the lasing light from the VCSEL to provide an electrical output signal for the optical displacement sensor which varies with the movement of the membrane.

  18. Multiplexed detection of DNA sequences using a competitive displacement assay in a microfluidic SERRS-based device.

    PubMed

    Yazdi, Soroush H; Giles, Kristen L; White, Ian M

    2013-11-01

    We demonstrate sensitive and multiplexed detection of DNA sequences through a surface enhanced resonance Raman spectroscopy (SERRS)-based competitive displacement assay in an integrated microsystem. The use of the competitive displacement scheme, in which the target DNA sequence displaces a Raman-labeled reporter sequence that has lower affinity for the immobilized probe, enables detection of unlabeled target DNA sequences with a simple single-step procedure. In our implementation, the displacement reaction occurs in a microporous packed column of silica beads prefunctionalized with probe-reporter pairs. The use of a functionalized packed-bead column in a microfluidic channel provides two major advantages: (i) immobilization surface chemistry can be performed as a batch process instead of on a chip-by-chip basis, and (ii) the microporous network eliminates the diffusion limitations of a typical biological assay, which increases the sensitivity. Packed silica beads are also leveraged to improve the SERRS detection of the Raman-labeled reporter. Following displacement, the reporter adsorbs onto aggregated silver nanoparticles in a microfluidic mixer; the nanoparticle-reporter conjugates are then trapped and concentrated in the silica bead matrix, which leads to a significant increase in plasmonic nanoparticles and adsorbed Raman reporters within the detection volume as compared to an open microfluidic channel. The experimental results reported here demonstrate detection down to 100 pM of the target DNA sequence, and the experiments are shown to be specific, repeatable, and quantitative. Furthermore, we illustrate the advantage of using SERRS by demonstrating multiplexed detection. The sensitivity of the assay, combined with the advantages of multiplexed detection and single-step operation with unlabeled target sequences makes this method attractive for practical applications. Importantly, while we illustrate DNA sequence detection, the SERRS-based competitive

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

    NASA Astrophysics Data System (ADS)

    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

  20. Inelastic column behavior

    NASA Technical Reports Server (NTRS)

    Duberg, John E; Wilder, Thomas W , III

    1952-01-01

    The significant findings of a theoretical study of column behavior in the plastic stress range are presented. When the behavior of a straight column is regarded as the limiting behavior of an imperfect column as the initial imperfection (lack of straightness) approaches zero, the departure from the straight configuration occurs at the tangent-modulus load. Without such a concept of the behavior of a straight column, one is led to the unrealistic conclusion that lateral deflection of the column can begin at any load between the tangent-modulus value and the Euler load, based on the original elastic modulus. A family of curves showing load against lateral deflection is presented for idealized h-section columns of various lengths and of various materials that have a systematic variation of their stress-strain curves.

  1. Mini-Column Ion-Exchange Separation and Atomic Absorption Quantitation of Nickel, Cobalt, and Iron: An Undergraduate Quantitative Analysis Experiment.

    ERIC Educational Resources Information Center

    Anderson, James L.; And Others

    1980-01-01

    Presents an undergraduate quantitative analysis experiment, describing an atomic absorption quantitation scheme that is fast, sensitive and comparatively simple relative to other titration experiments. (CS)

  2. Displaced patella fractures.

    PubMed

    Della Rocca, Gregory J

    2013-10-01

    Displaced patella fractures often result in disruption of the extensor mechanism of the knee. An intact extensor mechanism is a requirement for unassisted gait. Therefore, operative treatment of the displaced patella fracture is generally recommended. The evaluation of the patella fracture patient includes examination of extensor mechanism integrity. Operative management of patella fractures normally includes open reduction with internal fixation, although partial patellectomy is occasionally performed, with advancement of quadriceps tendon or patellar ligament to the fracture bed. Open reduction with internal fixation has historically been performed utilizing anterior tension band wiring, although comminution of the fracture occasionally makes this fixation construct inadequate. Supplementation or replacement of the tension band wire construct with interfragmentary screws, cerclage wire or suture, and/or plate-and-screw constructs may add to the stability of the fixation construct. Arthrosis of the patellofemoral joint is very common after healing of patella fractures, and substantial functional deficits may persist long after fracture healing has occurred.

  3. Tunable beam displacer

    SciTech Connect

    Salazar-Serrano, Luis José; Valencia, Alejandra; Torres, Juan P.

    2015-03-15

    We report the implementation of a tunable beam displacer, composed of a polarizing beam splitter (PBS) and two mirrors, that divides an initially polarized beam into two parallel beams whose separation can be continuously tuned. The two output beams are linearly polarized with either vertical or horizontal polarization and no optical path difference is introduced between them. The wavelength dependence of the device as well as the maximum separation between the beams achievable is limited mainly by the PBS characteristics.

  4. Competitive adsorption, displacement, and transport of organic matter on iron oxide: II. Displacement and transport

    NASA Astrophysics Data System (ADS)

    Gu, Baohua; Mehlhorn, Tonia L.; Liang, Liyuan; McCarthy, John F.

    1996-08-01

    The competitive interactions between organic matter compounds and mineral surfaces are poorly understood, yet these interactions may play a significant role in the stability and co-transport of mineral colloids and/or environmental contaminants. In this study, the processes of competitive adsorption, displacement, and transport of Suwannee River natural organic matter (SR-NOM) are investigated with several model organic compounds in packed beds of iron oxide-coated quartz columns. Results demonstrated that strongly-binding organic compounds are competitively adsorbed and displace those weakly-bound organic compounds along the flow path. Among the four organic compounds studied, polyacrylic acid (PAA) appeared to be the most competitive, whereas SR-NOM was more competitive than phthalic and salycylic acids. The transport of SR-NOM is found to involve a complex competitive interaction and displacement of different NOM subcomponents. A diffuse adsorption and sharp desorption front (giving an appearance of irreversible adsorption) of the SR-NOM breakthrough curves are explained as being a result of the competitive time-dependent adsorption and displacement processes between different organic components within the SR-NOM. The stability and transport of iron oxide colloids varied as one organic component competitively displaces another. Relatively large quantities of iron oxide colloids are transported when the more strongly-binding PAA competitively displaces the weakly-binding SR-NOM or when SR-NOM competitively displaces phthalic and salicylic acids. Results of this study suggest that the chemical composition and hence the functional behavior of NOM (e.g., in stabilizing mineral colloids and in complexing contaminants) can change along its flow path as a result of the dynamic competitive interactions between heterogeneous NOM subcomponents. Further studies are needed to better define and quantify these NOM components as well as their roles in contaminant partitioning

  5. Distillation Column Modeling Tools

    SciTech Connect

    2001-09-01

    Advanced Computational and Experimental Techniques will Optimize Distillation Column Operation. Distillation is a low thermal efficiency unit operation that currently consumes 4.8 quadrillion BTUs of energy...

  6. Inflatable Column Structure

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.

    1985-01-01

    Lightweight structural member easy to store. Billowing between circumferential loops of fiber inflated column becomes series of cells. Each fiber subjected to same tension along entire length (though tension is different in different fibers). Member is called "isotensoid" column. Serves as jack for automobiles or structures during repairs. Also used as support for temporary bleachers or swimming pools.

  7. Glass-silicon column

    DOEpatents

    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.

  8. Optimal design and experiment of a three-axis out-of-plane nano positioning stage using a new compact bridge-type displacement amplifier.

    PubMed

    Lee, Hak-Jun; Kim, Hyun-Chang; Kim, Hyo-Young; Gweon, Dae-Gab

    2013-11-01

    This paper presents the development of a new compact three-axis compliant stage employing piezoelectric actuators and a new flexure structure. A proposed stage works out-of-plane (Z, θx, θy) direction. The stage consists of 4 amplification flexures mounted piezoelectric actuators. New structure of flexure reduces height and enhances dynamic performance of stage. To certify excellent performance of the stage, comparison accomplished between conventional amplification flexure and new compact bridge type flexure. Modeling and optimal design of new type nano positioning stage performed. The optimal design is executed on the geometric parameters of the proposed flexure structure using Sequential Quadratic Programming. Experiments are carried out to verify the static and dynamic performance of the stage. The proposed out-of-plane nano-positioning stage has a Z-directional motion range 190 μm and a θx, θy-directional motion range ±2 mrad. The resolution of the stage is 4 nm, 40 nrad, and 40 nrad in the Z-, θx-, and θy-directional motions, respectively. The size of stage is 150 × 150 × 30 mm(3).

  9. Detachment of fullerene nC60 nanoparticles in saturated porous media under flow/stop-flow conditions: Column experiments and mechanistic explanations.

    PubMed

    Wang, Zhan; Wang, Dengjun; Li, Baoguo; Wang, Jizhong; Li, Tiantian; Zhang, Mengjia; Huang, Yuanfang; Shen, Chongyang

    2016-06-01

    This study was aimed at investigating the detachment of fullerene nC60 nanoparticles (NPs) in saturated sand porous media under transient and static conditions. The nC60 NPs were first attached at primary minima of Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energy profiles in electrolyte solutions with different ionic strengths (ISs). The columns were then eluted with deionized water to initiate nC60 NP detachment by decreasing solution IS. Finally, the flow of the columns was periodically interrupted to investigate nC60 NP detachment under static condition. Our results show that the detachment of nC60 NPs occurred under both transient and static conditions. The detachment under transient conditions was attributed to the fact that the attractions acting on the nC60 NPs at primary minima were weakened by nanoscale physical heterogeneities and overcome by hydrodynamic drags at lower ISs. However, a fraction of nC60 NPs remained at shallow primary minima in low flow regions, and detached via Brownian diffusion during flow interruptions. Greater detachment of nC60 NPs occurred under both transient and static conditions if the NPs were initially retained in electrolyte solutions with lower valent cations due to lower attractions between the NPs and collectors. Decrease in collector surface chemical heterogeneities and addition of dissolved organic matter also increased the extent of detachment by increasing electrostatic and steric repulsions, respectively. While particle attachment in and subsequent detachment from secondary minima occur in the same electrolyte solution, our results indicate that perturbation in solution chemistry is necessary to lower the primary minimum depths to initiate spontaneous detachment from the primary minima. These findings have important implications for predicting the fate and transport of nC60 NPs in subsurface environments during multiple rainfall events and accordingly for accurately assessing their environmental risks. PMID

  10. Epidemiological and Clinical Features of Cervical Column and Cord Injuries; A 2-Year Experience from a Large Trauma Center in Southern Iran

    PubMed Central

    Kamravan, Hamid Reza; Haghnegahdar, Ali; Paydar, Shahram; Khalife, Mohamad; Sedighi, Mahsa; Ghaffarpasand, Fariborz

    2014-01-01

    Objective: To describe the epidemiological characteristics of patients with cervical spine injury admitted to Rajaee hospital, Shiraz, Iran. Methods: This cross-sectional study includes all patients admitted with impression of cervical column injury with or without cervical cord injury from October 2009 to March 2012 to our level I trauma center in Shiraz. We recorded the patients’ characteristics including age, sex, marital status, mechanism of injury, level of injury, concomitant injury, treatment(non-operative or operative) and clinical outcome. The data were described and compared with the international literature. Results: Among 261 patients referred with impression of spinal cord injury, the diagnosis of spinal column injury (with or without spine cord injury) was confirmed in 206 patients. The mean age of patients was 37.2±15.9 years with Male/Female ratio of 3:1. Car turn-over  and car-collisions were the leading causes of injury. The most common spine fracture was C6 vertebra involving 60 (29.1%) patients. Fracture of upper and lower extremities were the most concomitant fractures observed in 31(15.1%) patients. Open surgery was performed in 65(31.6%).Mortality rate was 7.3% (15 patients).Patients with brain, lung and cord injuries had increased risk of death, among 15 deaths,9 patients had brain injury, 5 individuals had lung injury and 10 patients suffered from cord injury. Conclusion: Cervical spine injuries mostly affect young males, and comprise 206 (10%) cases out of 2100 spine injuries in our country. Preventive measures should be taken to reduce cervical spine injuries especially in young age group. PMID:27162861

  11. Synthesis of finite displacements and displacements in continental margins

    NASA Technical Reports Server (NTRS)

    Speed, R. C.; Elison, M. W.; Heck, F. R.; Russo, R. M.

    1988-01-01

    The scope of the project is the analysis of displacement-rate fields in the transitional regions between cratonal and oceanic lithospheres over Phanerozoic time (last 700 ma). Associated goals are an improved understanding of range of widths of major displacement zones; the partition of displacement gradients and rotations with position and depth in such zones; the temporal characteristics of such zones-the steadiness, episodicity, and duration of uniform versus nonunifrom fields; and the mechanisms and controls of the establishment and kinematics of displacement zones. The objective is to provide a context of time-averaged kinematics of displacement zones. The initial phase is divided topically among the methodology of measurement and reduction of displacements in the lithosphere and the preliminary analysis from geologic and other data of actual displacement histories from the Cordillera, Appalachians, and southern North America.

  12. Leachate migration from spent mushroom substrate through intact and repacked subsurface soil columns.

    PubMed

    Guo, Mingxin; Chorover, Jon

    2006-01-01

    Field weathering of spent mushroom substrate (SMS) produces soluble compost leachate that percolates into underlying soils and may adversely impact groundwater. Laboratory experiments were conducted to investigate movement and retention of SMS leachate solutes in subsurface soil columns. Spent mushroom substrate leachate with high concentrations of dissolved organic matter (DOM) and inorganic salts was passively loaded to intact and repacked columns of Bt1 soil (fine-loamy, mixed, semiactive, mesic Typic Hapludults) and effluents were monitored for changes in chemical composition. Transport of SMS leachate in undisturbed soil cores was mainly via preferential flow, whereas matrix flow was predominant in repacked soil columns. Leachate DOM and phosphate were sorbed by soil minerals while Cl-, SO4(2-), Na+ and NH4+ were eluted. Leachate K+ displaced exchangeable native cations and was retained. Biodegradation of leachate DOM resulted in reduction and elution of soil Mn and Fe, especially in repacked columns. Persistent anoxia also inhibited nitrification. Precipitation of gypsum and CaCO3 blocked preferential flow channels, and movement of SMS leachate was subsequently reduced. The results demonstrate that SMS leachate migrates via rapid preferential flow initially, followed by matrix flow at a lower rate. Leachate solutes may transport to depth in soil profiles through preferential channels. To protect water resources, weathering of deep SMS piles should be conducted on compact surfaces or in fields with a condensed soil layer (no structural cracks) above the groundwater table, and measures controlling leachate runoff be imposed.

  13. Competitive adsorption, displacement, and transport of organic matter on iron oxide: II. Displacement and transport

    SciTech Connect

    Gu, B; Mehlhorn, T.L.; Liang, Liyuan

    1996-08-01

    The competitive interactions between organic matter compounds and mineral surfaces are poorly understood, yet these interactions may play a significant role in the stability and co-transport of mineral colloids and/or environmental contaminants. In this study, the processes of competitive adsorption, displacement, and transport of Suwannee River natural organic matter (SR-NOM) are investigated with several model organic compounds in packed beds of iron oxide-coated quartz columns. Results demonstrated that strongly-binding organic compounds are competitively adsorbed and displace those weakly-bound organic compounds along the flow path. Among the four organic compounds studied, polyacrylic acid (PAA) appeared to be the most competitive, whereas SR-NOM was more competitive than phthalic and salicylic acids. A diffuse adsorption and sharp desorption front (giving an appearance of irreversible adsorption) of the SR-NOM breakthrough curves are explained as being a result of the competitive time-dependent adsorption and displacement processes between different organic components within the SR-NOM. The stability and transport of iron oxide colloids varied as one organic component competitively displaces another. Relatively large quantities of iron oxide colloids are transported when the more strongly-binding PAA competitively displaces the weakly-binding SR-NOM or when SR-NOM competitively displaces phthalic and salicylic acids. Results of this study suggest that the chemical composition and hence the functional behavior of NOM (e.g., in stabilizing mineral colloids and in complexing contaminants) can change along its flow path as a result of the dynamic competitive interactions between heterogeneous NOM subcomponents. Further studies are needed to better define and quantify these NOM components as well as their roles in contaminant partitioning and transport. 37 refs., 10 figs.

  14. Nuclear reactor control column

    DOEpatents

    Bachovchin, Dennis M.

    1982-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Huz, Kateryna

    2014-01-01

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

  16. Development of fine-resolution analyses and expanded large-scale forcing properties. Part II: Scale-awareness and application to single-column model experiments

    DOE PAGESBeta

    Feng, Sha; Vogelmann, Andrew M.; Li, Zhijin; Liu, Yangang; Lin, Wuyin; Zhang, Minghua; Toto, Tami; Endo, Satoshi

    2015-01-20

    Fine-resolution three-dimensional fields have been produced using the Community Gridpoint Statistical Interpolation (GSI) data assimilation system for the U.S. Department of Energy’s Atmospheric Radiation Measurement Program (ARM) Southern Great Plains region. The GSI system is implemented in a multi-scale data assimilation framework using the Weather Research and Forecasting model at a cloud-resolving resolution of 2 km. From the fine-resolution three-dimensional fields, large-scale forcing is derived explicitly at grid-scale resolution; a subgrid-scale dynamic component is derived separately, representing subgrid-scale horizontal dynamic processes. Analyses show that the subgrid-scale dynamic component is often a major component over the large-scale forcing for grid scalesmore » larger than 200 km. The single-column model (SCM) of the Community Atmospheric Model version 5 (CAM5) is used to examine the impact of the grid-scale and subgrid-scale dynamic components on simulated precipitation and cloud fields associated with a mesoscale convective system. It is found that grid-scale size impacts simulated precipitation, resulting in an overestimation for grid scales of about 200 km but an underestimation for smaller grids. The subgrid-scale dynamic component has an appreciable impact on the simulations, suggesting that grid-scale and subgrid-scale dynamic components should be considered in the interpretation of SCM simulations.« less

  17. Development of fine-resolution analyses and expanded large-scale forcing properties. Part II: Scale-awareness and application to single-column model experiments

    SciTech Connect

    Feng, Sha; Vogelmann, Andrew M.; Li, Zhijin; Liu, Yangang; Lin, Wuyin; Zhang, Minghua; Toto, Tami; Endo, Satoshi

    2015-01-20

    Fine-resolution three-dimensional fields have been produced using the Community Gridpoint Statistical Interpolation (GSI) data assimilation system for the U.S. Department of Energy’s Atmospheric Radiation Measurement Program (ARM) Southern Great Plains region. The GSI system is implemented in a multi-scale data assimilation framework using the Weather Research and Forecasting model at a cloud-resolving resolution of 2 km. From the fine-resolution three-dimensional fields, large-scale forcing is derived explicitly at grid-scale resolution; a subgrid-scale dynamic component is derived separately, representing subgrid-scale horizontal dynamic processes. Analyses show that the subgrid-scale dynamic component is often a major component over the large-scale forcing for grid scales larger than 200 km. The single-column model (SCM) of the Community Atmospheric Model version 5 (CAM5) is used to examine the impact of the grid-scale and subgrid-scale dynamic components on simulated precipitation and cloud fields associated with a mesoscale convective system. It is found that grid-scale size impacts simulated precipitation, resulting in an overestimation for grid scales of about 200 km but an underestimation for smaller grids. The subgrid-scale dynamic component has an appreciable impact on the simulations, suggesting that grid-scale and subgrid-scale dynamic components should be considered in the interpretation of SCM simulations.

  18. Efficacy of reactive mineral-based sorbents for phosphate, bacteria, nitrogen and TOC removal--column experiment in recirculation batch mode.

    PubMed

    Nilsson, Charlotte; Lakshmanan, Ramnath; Renman, Gunno; Rajarao, Gunaratna Kuttuva

    2013-09-15

    Two mineral-based materials (Polonite and Sorbulite) intended for filter wells in on-site wastewater treatment were compared in terms of removal of phosphate (PO4-P), total inorganic nitrogen (TIN), total organic carbon (TOC) and faecal indicator bacteria (Escherichia coli and Enterococci). Using an innovative, recirculating system, septic tank effluent was pumped at a hydraulic loading rate of 3000 L m(2) d(-1) into triplicate bench-scale columns of each material over a 90-day period. The results showed that Polonite performed better with respect to removal of PO4-P, retaining on average 80% compared with 75% in Sorbulite. This difference was attributed to higher CaO content in Polonite and its faster dissolution. Polonite also performed better in terms of removal of bacteria because of its higher pH value. The total average reduction in E. coli was 60% in Polonite and 45% in Sorbulite, while for Enterococci the corresponding value was 56% in Polonite and 34% in Sorbulite. Sorbulite removed TIN more effectively, with a removal rate of 23%, while Polonite removed 11% of TIN, as well as TOC. Organic matter (measured as TOC) was accumulated in the filter materials but was also released periodically. The results showed that Sorbulite could meet the demand in removing phosphate and nitrogen with reduced microbial release from the wastewater treatment process.

  19. Fingering phenomena during grain-grain displacement

    NASA Astrophysics Data System (ADS)

    Mello, Nathália M. P.; Paiva, Humberto A.; Combe, G.; Atman, A. P. F.

    2016-05-01

    Spontaneous formation of fingered patterns during the displacement of dense granular assemblies was experimentally reported few years ago, in a radial Hele-Shaw cell. Here, by means of discrete element simulations, we have recovered the experimental findings and extended the original study to explore the control parameters space. In particular, using assemblies of grains with different geometries (monodisperse, bidisperse, or polydisperse), we measured the macroscopic stress tensor in the samples in order to confirm some conjectures proposed in analogy with Saffman-Taylor viscous fingering phenomena for immiscible fluids. Considering an axial setup which allows to control the discharge of grains and to follow the trajectory and the pressure gradient along the displacing interface, we have applied the Darcy law for laminar flow in fluids in order to measure an "effective viscosity" for each assembly combination, in an attempt to mimic variation of the viscosity ratio between the injected/displaced fluids in the Saffman-Taylor experiment. The results corroborate the analogy with the viscous fluids displacement, with the bidisperse assembly corresponding to the less viscous geometry. But, differently to fluid case, granular fingers only develop for a specific combination of displaced/injected geometries, and we have demonstrated that it is always related with the formation of a force chain network along the finger direction.

  20. Microminiature gas chromatographic column

    NASA Technical Reports Server (NTRS)

    Donaldson, R. W., Jr.

    1972-01-01

    Techniques commonly used for fabrication of integrated circuits are utilized to produce long capillary tubes for microminiature chromatographs. Method involves bonding of flat silicon plate to top of spirally grooved silicon chip to close groove and form capillary column.

  1. Distillation Column Flooding Predictor

    SciTech Connect

    2002-02-01

    This factsheet describes a research project whose goal is to develop the flooding predictor, an advanced process control strategy, into a universally useable tool that will maximize the separation yield of a distillation column.

  2. The dependence of edge displacement thresholds on edge blur, contrast, and displacement distance.

    PubMed

    Mather, G

    1987-01-01

    Two experiments measured thresholds for discriminating the movement direction of an isolated intensity edge. The luminance profile of the edge took the form of an integrated Gaussian. In the first experiment, displacement thresholds were measured as a function of edge blur width and contrast. In the second experiment, contrast thresholds were measured as a function of edge blur width and displacement. Using the estimated retinal profile of the edge (given the LSF of the display and of the optics of the eye), the data were found to collapse onto a single function relating the maximum spatial luminance gradient defined by the edge to the maximum temporal change in luminance generated by its displacement. There was a direct relationship between the two gradients at threshold, so that lower spatial gradients were paired with smaller temporal changes. Implications for current models of motion detection are examined.

  3. Strategies for displacing oil

    NASA Astrophysics Data System (ADS)

    Rao, Vikram; Gupta, Raghubir

    2015-03-01

    Oil currently holds a monopoly on transportation fuels. Until recently biofuels were seen as the means to break this stranglehold. They will still have a part to play, but the lead role has been handed to natural gas, almost solely due to the increased availability of shale gas. The spread between oil and gas prices, unprecedented in its scale and duration, will cause a secular shift away from oil as a raw material. In the transport fuel sector, natural gas will gain traction first in the displacement of diesel fuel. Substantial innovation is occurring in the methods of producing liquid fuel from shale gas at the well site, in particular in the development of small scale distributed processes. In some cases, the financing of such small-scale plants may require new business models.

  4. Variable displacement blower

    DOEpatents

    Bookout, Charles C.; Stotts, Robert E.; Waring, Douglass R.; Folsom, Lawrence R.

    1986-01-01

    A blower having a stationary casing for rotatably supporting a rotor assembly having a series of open ended chambers arranged to close against the surrounding walls of the casing. Pistons are slidably mounted within each chamber with the center of rotation of the pistons being offset in regard to the center of rotation of the rotor assembly whereby the pistons reciprocate in the chambers as the rotor assembly turns. As inlet port communicates with the rotor assembly to deliver a working substance into the chamber as the pistons approach a top dead center position in the chamber while an outlet port also communicates with the rotor to exhaust the working substance as the pistons approach a bottom dead center position. The displacement of the blower is varied by adjusting the amount of eccentricity between the center of rotation of the pistons and the center of rotation of the rotor assembly.

  5. Displacement parameter inversion for a novel electromagnetic underground displacement sensor.

    PubMed

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-05-22

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named "EELA forward modeling-approximate inversion method". Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0-100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications.

  6. Displacement parameter inversion for a novel electromagnetic underground displacement sensor.

    PubMed

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-01-01

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named "EELA forward modeling-approximate inversion method". Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0-100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications. PMID:24858960

  7. Displacement Parameter Inversion for a Novel Electromagnetic Underground Displacement Sensor

    PubMed Central

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-01-01

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named “EELA forward modeling-approximate inversion method”. Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0–100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications. PMID:24858960

  8. Towards Atomic Column-by-Column Spectroscopy

    SciTech Connect

    Pennycook, S.J.; Rafferty, B.

    1998-09-06

    The optical arrangement of the scanning transmission electron microscope (STEM) is ideally suited for performing analysis of individual atomic columns in materials. Using the incoherent Z-contrast image as a reference, and arranging incoherent conditions also for the spectroscopy, a precise correspondence is ensured between features in the inelastic image and elastic signals. In this way the exact probe position needed to maximise the inelastic signal from a selected column can be located and monitored during the analysis using the much higher intensity elastic signal. Although object functions for EELS are typically less than 1 {Angstrom} full width at half maximum, this is still an order of magnitude larger than the corresponding object functions for elastic (or diffuse) scattering used to form the Z-contrast image. Therefore the analysis is performed with an effective probe that is significantly broader than that used for the reference Z-contrast image. For a 2.2 {Angstrom} probe the effective probe is of the order of 2.5 {Angstrom}, while for a 1.3 {Angstrom} probe the effective probe is 1.6 {Angstrom}. Such increases in effective probe size can significantly reduce or even eliminate contrast between atomic columns that are visible in the image. However, this is only true if we consider circular collector apertures. Calculations based upon the theory of Maslen and Rossouw (Maslen and Rossouw 1984; Rossouw and Maslen 1984) show that employing an annular aperture can reduce the FWHM of the inelastic object function down to values close 0.1 {Angstrom}. With practical aperture sizes it should be possible to achieve this increased spatial resolution without loosing too much signal.

  9. 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.

    PubMed

    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

  10. 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.

    PubMed

    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

  11. Eruption column physics

    SciTech Connect

    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.

  12. The development of mitochondrial membrane affinity chromatography columns for the study of mitochondrial transmembrane proteins

    PubMed Central

    Habicht, K-L.; Singh, N.S.; Indig, F.E.; Wainer, I.W.; Moaddel, R.; Shimmo, R.

    2015-01-01

    Mitochondrial membrane fragments from U-87 MG (U87MG) and HEK-293 cells were successfully immobilized on to Immobilized Artificial Membrane (IAM) chromatographic support and surface of activated open tubular (OT) silica capillary resulting in mitochondrial membrane affinity chromatography (MMAC) columns. Translocator protein (TSPO), located in mitochondrial outer membrane as well as sulfonylurea and mitochondrial permeability transition pore (mPTP) receptors, localized to the inner membrane, were characterized. Frontal displacement experiments with multiple concentrations of dipyridamole (DIPY) and PK-11195 were run on MMAC-(U87MG) column and the binding affinities (Kd) determined were 1.08 ± 1.49 and 0.0086 ± 0.0006 μM respectively, which was consistent with previously reported values. Further, binding affinities (Ki) for DIPY binding site were determined for TSPO ligands, PK-11195, mesoporphyrin IX, protoporphyrin IX and rotenone. Additionally, the relative ranking of these TSPO ligands based on single displacement studies using DIPY as marker on MMAC-(U87MG) was consistent with the obtained Ki values. The immobilization of mitochondrial membrane fragments was also confirmed by confocal microscopy. PMID:26049098

  13. The development of mitochondrial membrane affinity chromatography columns for the study of mitochondrial transmembrane proteins.

    PubMed

    Habicht, K-L; Singh, N S; Indig, F E; Wainer, I W; Moaddel, R; Shimmo, R

    2015-09-01

    Mitochondrial membrane fragments from U-87 MG (U87MG) and HEK-293 cells were successfully immobilized onto immobilized artificial membrane (IAM) chromatographic support and surface of activated open tubular (OT) silica capillary, resulting in mitochondrial membrane affinity chromatography (MMAC) columns. Translocator protein (TSPO), located in mitochondrial outer membrane as well as sulfonylurea and mitochondrial permeability transition pore (mPTP) receptors, localized to the inner membrane, were characterized. Frontal displacement experiments with multiple concentrations of dipyridamole (DIPY) and PK-11195 were run on MMAC (U87MG) column, and the binding affinities (Kd) determined were 1.08±0.49 and 0.0086±0.0006μM, respectively, consistent with previously reported values. Furthermore, binding affinities (Ki) for DIPY binding site were determined for TSPO ligands, PK-11195, mesoporphyrin IX, protoporphyrin IX, and rotenone. In addition, the relative ranking of these TSPO ligands based on single displacement studies using DIPY as marker on MMAC (U87MG) was consistent with the obtained Ki values. The immobilization of mitochondrial membrane fragments was also confirmed by confocal microscopy. PMID:26049098

  14. Displacement, Substitution, Sublimation: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    Sigmund Freund worked with the mechanisms of displacement, substitution, and sublimation. These mechanisms have many similarities and have been studied diagnostically and therapeutically. Displacement and substitution seem to fit in well with phobias, hysterias, somatiyations, prejudices, and scapegoating. Phobias, prejudices, and scapegoating…

  15. Displaced Homemakers Project. Leader's Guide.

    ERIC Educational Resources Information Center

    Musickant, Claire

    This handbook is designed to assist vocational technical adult education providers in developing workshops for displaced homemakers. Covered first are various aspects of planning a displaced homemakers workshop, including format, time, location, publicity and recruitment, staff and presenters, community resources, budget items, and other…

  16. Columns in Clay

    ERIC Educational Resources Information Center

    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…

  17. Depth-resolved water column spectral absorption of sunlight by phytoplankon during the Southern Ocean Gas Exchange (SOGasEx) Lagrangian tracer experiments

    NASA Astrophysics Data System (ADS)

    Hargreaves, B. R.

    2008-12-01

    Optical measurements made during gas exchange tracer experiments in the Southern Ocean, Atlantic sector near 51°S, 38°W from March-April 2008 (SOGasEx) were used to develop daily integrated depth- resolved PAR absorbed by phytoplankton. Particulate and phytoplankton pigment spectral absorption coefficients (ap and aph), and methanol-extracted chlorophyll-a concentrations (chl-a) from discrete samples within and below the upper mixed layer (40 stations) were combined with data from optical casts where chlorophyll-a and cdom fluorescence and PAR scalar irradiance were measured (11 stations), PAR Kd was measured from a buoy free of ship shadow for 0-5m (11 stations), and Wetlabs AC-9 whole water absorption coefficients to 150m were measured (14 stations, with 3 in common with fluorescence data) to estimate depth-resolved values for both total spectral absorption and spectral PAR irradiance. By combining depth-adjusted spectral absorption of phytoplankton pigments (aph) with depth-adjusted PAR spectral irradiance we estimated depth-resolved daily PAR irradiance absorbed by photosynthetic pigments. These data can be compared with time-integrated primary production measurements conducted on deck where solar exposure or lamp exposure was modified to simulate a range of depths. Such a synthesis should improve our estimates of depth-integrated daily primary production, and ultimately contribute to refining estimates of carbon export rates to be incorporated into a carbon budget and CO2 air-sea flux models for the SOGasEx experiments.

  18. METHOD TO TEST ISOTOPIC SEPARATION EFFICIENCY OF PALLADIUM PACKED COLUMNS

    SciTech Connect

    Heung, L; Gregory Staack, G; James Klein, J; William Jacobs, W

    2007-06-27

    The isotopic effect of palladium has been applied in different ways to separate hydrogen isotopes for many years. At Savannah River Site palladium deposited on kieselguhr (Pd/k) is used in a thermal cycling absorption process (TCAP) to purify tritium for over ten years. The need to design columns for different throughputs and the desire to advance the performance of TCAP created the need to evaluate different column designs and packing materials for their separation efficiency. In this work, columns with variations in length, diameter and metal foam use, were tested using an isotope displacement method. A simple computer model was also developed to calculate the number of theoretical separation stages using the test results. The effects of column diameter, metal foam and gas flow rate were identified.

  19. Regenerative rotary displacer Stirling engine

    SciTech Connect

    Isshiki, Naotsugu; Watanabe, Hiroichi; Raggi, L.; Isshiki, Seita; Hirata, Koichi

    1996-12-31

    A few rotary displacer Stirling engines in which the displacer has one gas pocket space at one side and rotates in a main enclosed cylinder, which is heated from one side and cooled from opposite side without any regenerator, have been studied for some time by the authors. The authors tried to improve this engine by equipping it with a regenerator, because without a regenerator, pressure oscillation and efficiency are too small. Here, several types of regenerative rotary displacer piston Stirling engines are proposed. One is the contra-rotating tandem two disc type displacer engine using axial heat conduction through side walls or by heat pipes and another is a single disc type with circulating fluid regenerator or heat pipes. Stirling engines of this new rotary displacer type are thought to attain high speed. Here, experimental results of the original rotary displacer Stirling engine without a regenerator, and one contra-rotating tandem displacer engine with side wall regenerator by axial heat conduction are reported accompanied with a discussion of the results.

  20. Development and validation of a model of bio-barriers for remediation of Cr(VI) contaminated aquifers using laboratory column experiments.

    PubMed

    Shashidhar, T; Bhallamudi, S Murty; Philip, Ligy

    2007-07-16

    Bench scale transport and biotransformation experiments and mathematical model simulations were carried out to study the effectiveness of bio-barriers for the containment of hexavalent chromium in contaminated confined aquifers. Experimental results showed that a 10cm thick bio-barrier with an initial biomass concentration of 0.205mg/g of soil was able to completely contain a Cr(VI) plume of 25mg/L concentration. It was also observed that pore water velocity and initial biomass concentration are the most significant parameters in the containment of Cr(VI). The mathematical model developed is based on one-dimensional advection-dispersion reaction equations for Cr(VI) and molasses in saturated, homogeneous porous medium. The transport of Cr(VI) and molasses is coupled with adsorption and Monod's inhibition kinetics for immobile bacteria. It was found that, in general, the model was able to simulate the experimental results satisfactorily. However, there was disparity between the numerically simulated and experimental breakthrough curves for Cr(VI) and molasses in cases where there was high clay content and high microbial activity. The mathematical model could contribute towards improved designs of future bio-barriers for the remediation of Cr(VI) contaminated aquifers.

  1. Borehole optical lateral displacement sensor

    DOEpatents

    Lewis, R.E.

    1998-10-20

    There is provided by this invention an optical displacement sensor that utilizes a reflective target connected to a surface to be monitored to reflect light from a light source such that the reflected light is received by a photoelectric transducer. The electric signal from the photoelectric transducer is then imputed into electronic circuitry to generate an electronic image of the target. The target`s image is monitored to determine the quantity and direction of any lateral displacement in the target`s image which represents lateral displacement in the surface being monitored. 4 figs.

  2. Research on Joint Parameter Inversion for an Integrated Underground Displacement 3D Measuring Sensor

    PubMed Central

    Shentu, Nanying; Qiu, Guohua; Li, Qing; Tong, Renyuan; Shentu, Nankai; Wang, Yanjie

    2015-01-01

    Underground displacement monitoring is a key means to monitor and evaluate geological disasters and geotechnical projects. There exist few practical instruments able to monitor subsurface horizontal and vertical displacements simultaneously due to monitoring invisibility and complexity. A novel underground displacement 3D measuring sensor had been proposed in our previous studies, and great efforts have been taken in the basic theoretical research of underground displacement sensing and measuring characteristics by virtue of modeling, simulation and experiments. This paper presents an innovative underground displacement joint inversion method by mixing a specific forward modeling approach with an approximate optimization inversion procedure. It can realize a joint inversion of underground horizontal displacement and vertical displacement for the proposed 3D sensor. Comparative studies have been conducted between the measured and inversed parameters of underground horizontal and vertical displacements under a variety of experimental and inverse conditions. The results showed that when experimentally measured horizontal displacements and vertical displacements are both varied within 0 ~ 30 mm, horizontal displacement and vertical displacement inversion discrepancies are generally less than 3 mm and 1 mm, respectively, under three kinds of simulated underground displacement monitoring circumstances. This implies that our proposed underground displacement joint inversion method is robust and efficient to predict the measuring values of underground horizontal and vertical displacements for the proposed sensor. PMID:25871714

  3. Research on joint parameter inversion for an integrated underground displacement 3D measuring sensor.

    PubMed

    Shentu, Nanying; Qiu, Guohua; Li, Qing; Tong, Renyuan; Shentu, Nankai; Wang, Yanjie

    2015-01-01

    Underground displacement monitoring is a key means to monitor and evaluate geological disasters and geotechnical projects. There exist few practical instruments able to monitor subsurface horizontal and vertical displacements simultaneously due to monitoring invisibility and complexity. A novel underground displacement 3D measuring sensor had been proposed in our previous studies, and great efforts have been taken in the basic theoretical research of underground displacement sensing and measuring characteristics by virtue of modeling, simulation and experiments. This paper presents an innovative underground displacement joint inversion method by mixing a specific forward modeling approach with an approximate optimization inversion procedure. It can realize a joint inversion of underground horizontal displacement and vertical displacement for the proposed 3D sensor. Comparative studies have been conducted between the measured and inversed parameters of underground horizontal and vertical displacements under a variety of experimental and inverse conditions. The results showed that when experimentally measured horizontal displacements and vertical displacements are both varied within 0~30 mm, horizontal displacement and vertical displacement inversion discrepancies are generally less than 3 mm and 1 mm, respectively, under three kinds of simulated underground displacement monitoring circumstances. This implies that our proposed underground displacement joint inversion method is robust and efficient to predict the measuring values of underground horizontal and vertical displacements for the proposed sensor. PMID:25871714

  4. Character displacement of song and morphology in African tinkerbirds

    PubMed Central

    Kirschel, Alexander N. G.; Blumstein, Daniel T.; Smith, Thomas B.

    2009-01-01

    Divergence in acoustic signals between populations of animals can lead to species recognition failure, reproductive isolation, and speciation. Character displacement may facilitate coexistence of species in natural communities, yet evidence for character displacement in acoustic signals is scant. Here, we find evidence of character displacement in song as well as body size and bill size of 2 related African tinkerbirds. Playback experiments indicate that related species' songs are perceived differently in sympatry than in allopatry. We suggest character displacement occurs in phenotypic traits facilitating species recognition, which has important implications for understanding the processes that lead to speciation and diversification. Because many of the sites where the 2 species coexist are areas where pristine rainforest has been degraded, results also suggest that anthropogenic pressures resulting from deforestation may be a contributing cause of character displacement in these species. PMID:19420223

  5. Apes communicate about absent and displaced objects: methodology matters.

    PubMed

    Lyn, Heidi; Russell, Jamie L; Leavens, David A; Bard, Kim A; Boysen, Sarah T; Schaeffer, Jennifer A; Hopkins, William D

    2014-01-01

    Displaced reference is the ability to refer to an item that has been moved (displaced) in space and/or time, and has been called one of the true hallmarks of referential communication. Several studies suggest that nonhuman primates have this capability, but a recent experiment concluded that in a specific situation (absent entities), human infants display displaced reference but chimpanzees do not. Here, we show that chimpanzees and bonobos of diverse rearing histories are capable of displaced reference to absent and displaced objects. It is likely that some of the conflicting findings from animal cognition studies are due to relatively minor methodological differences, but are compounded by interpretation errors. Comparative studies are of great importance in elucidating the evolution of human cognition; however, greater care must be taken with methodology and interpretation for these studies to accurately reflect species differences.

  6. 11. TIMBER COLUMN AND CAST IRON COLUMN CAP IN FIFTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. TIMBER COLUMN AND CAST IRON COLUMN CAP IN FIFTH FLOOR WAREHOUSE SPACE. VIEW TO SOUTHWEST. - Commercial & Industrial Buildings, Becker-Hazelton Company Warehouse, 280 Iowa Street, Dubuque, Dubuque County, IA

  7. Displacement sensing system and method

    DOEpatents

    VunKannon, Jr., Robert S

    2006-08-08

    A displacement sensing system and method addresses demanding requirements for high precision sensing of displacement of a shaft, for use typically in a linear electro-dynamic machine, having low failure rates over multi-year unattended operation in hostile environments. Applications include outer space travel by spacecraft having high-temperature, sealed environments without opportunity for servicing over many years of operation. The displacement sensing system uses a three coil sensor configuration, including a reference and sense coils, to provide a pair of ratio-metric signals, which are inputted into a synchronous comparison circuit, which is synchronously processed for a resultant displacement determination. The pair of ratio-metric signals are similarly affected by environmental conditions so that the comparison circuit is able to subtract or nullify environmental conditions that would otherwise cause changes in accuracy to occur.

  8. Boundary effects on solute transport in finite soil columns

    NASA Astrophysics Data System (ADS)

    Schwartz, R. C.; McInnes, K. J.; Juo, A. S. R.; Wilding, L. P.; Reddell, D. L.

    1999-03-01

    This study investigates the influence of inlet and outlet disturbances and formulated boundary conditions on the estimation of the dispersion coefficient and retardation factor for short soil columns. Unsaturated miscible displacement experiments utilizing a Br- tracer were carried out on undisturbed columns of a fine-textured Ultisol. Solutions were applied using either a fritted plate or an array of dispensing tips that produced droplets at a prescribed flow rate. One- and two-layer analytical solutions of the advective-dispersive equation were fitted to effluent concentrations using nonlinear least squares parameter optimization. Comparison of two-layer simulations with experimental data indicated that the analytical solution with a semi-infinite interface boundary best approximated effluent concentrations under the conditions of this study. This solution corresponds to a continuous flux concentration and a macroscopically discontinuous resident concentration at the interface between the soil and porous plates. Parameter estimates were not significantly different with respect to the application method used at the inlet. This may be attributed to a less uniform distribution of solution onto the soil surface by the drip apparatus and/or by the presence of stagnant regions within the inlet reservoir and hence increased dispersion within the inlet platen apparatus. Two-layer simulations indicated that the dispersion coefficient was underestimated by 14-27% when the influence of the inlet and outlet apparatus were not included in the fitted solution of the advective-dispersive equation. In addition, use of one-layer analytical solutions caused the retardation factor to be overestimated by no more than the fractional increase in pore volume imparted by the platen apparatus.

  9. Counterflow isotachophoresis in a monolithic column.

    PubMed

    Liu, Bingwen; Cong, Yongzheng; Ivory, Cornelius F

    2014-09-01

    This study describes stationary counterflow isotachophoresis (ITP) in a poly(acrylamide-co-N,N'-methylenebisacrylamide) monolithic column as a means for improving ITP processing capacity and reducing dispersion. The flow profile in the monolith was predicted using COMSOL's Brinkman Equation application mode, which revealed that the flow profile was mainly determined by monolith permeability. As monolith permeability decreases, the flow profile changes from a parabolic shape to a plug shape. An experimental monolithic column was prepared in a fused-silica capillary using an ultraviolet-initiated polymerization method. A monolithic column made from 8% (wt.) monomer was chosen for the stationary counterflow ITP experiments. Counterflow ITP in the monolithic column showed undistorted analyte zones with significantly reduced dispersion compared to the severe dispersion observed in an open capillary. Particularly, for r-phycoerythrin focused by counterflow ITP, its zone width in the monolithic column was only one-third that observed in an open capillary. These experiments demonstrate that stationary counterflow ITP in monoliths can be a robust and practical electrofocusing method.

  10. Dispersants displace hot oiling

    SciTech Connect

    Wash, R.

    1984-02-01

    Laboratory experiments and field testing of dispersants in producing wells have resulted in development of 2 inexpensive paraffin dispersant packages with a broad application range, potential for significant savings over hot oiling, and that can be applied effectively by both continuous and batch treating techniques. The 2 dispersants are soluble in the carrier solvent (one soluble in oil, one in water); are able to readily disperse the wax during a hot flask test conducted in a laboratory; and leave the producing interval water wet. Field data on the 2 dispersants are tabulated, demonstrating their efficacy.

  11. Evaluation of simultaneous reduction and transport of selenium in saturated soil columns

    NASA Astrophysics Data System (ADS)

    Guo, Lei; Frankenberger, William T.; Jury, William A.

    1999-03-01

    Speciation plays an important role in determining the overall leachability of selenium in soil. In this study we present a mathematical model and results of miscible displacement experiments that were conducted to evaluate simultaneous reduction and transport of selenate in saturated soil columns. The experiments were carried out in organic amended (compost manure or gluten) or unamended soil, with O2-sparged or nonsparged influent solution. In all columns, reduction of selenate was fast enough to produce selenite flux in the effluent and elemental Se in the soil profile during a mean residence time of ˜30 hours. Reduction was accelerated in the presence of organic amendments and under low O2 concentrations, resulting in an increased retardation of selenium transport as a whole. The results of our experiments show that although selenate does not sorb to solid surfaces during transport, it reduces rapidly to forms that are strongly retarded. On the basis of simulation with the consecutive reaction and transport model using parameters derived from this study, selenium is expected to be retained near the soil surface, even under extreme leaching conditions.

  12. Emergency contraception among refugees and the displaced.

    PubMed

    Goodyear, L; McGinn, T

    1998-01-01

    In 1994, the international relief community began to recognize and address the reproductive health needs of refugees and displaced populations. A minimum initial service package of reproductive health services for refugees and the displaced, which includes emergency contraception (EC), was developed and recommended for use in refugee settings. This paper describes the experience of one international relief organization, the International Rescue Committee (IRC), in introducing EC into its worldwide reproductive health program. A recent IRC survey found that EC is available in 4 out of 14 settings where it provides reproductive health services. A case study from Tanzania demonstrates the modes of delivery, the demand for EC by women who have experienced sexual violence, and the community responses to this method of contraception. More information, education, and communication directed at refugee communities; more donor support for supplies; and institutional commitment to train staff are needed to expand refugee access to EC. PMID:9859638

  13. Emergency contraception among refugees and the displaced.

    PubMed

    Goodyear, L; McGinn, T

    1998-01-01

    In 1994, the international relief community began to recognize and address the reproductive health needs of refugees and displaced populations. A minimum initial service package of reproductive health services for refugees and the displaced, which includes emergency contraception (EC), was developed and recommended for use in refugee settings. This paper describes the experience of one international relief organization, the International Rescue Committee (IRC), in introducing EC into its worldwide reproductive health program. A recent IRC survey found that EC is available in 4 out of 14 settings where it provides reproductive health services. A case study from Tanzania demonstrates the modes of delivery, the demand for EC by women who have experienced sexual violence, and the community responses to this method of contraception. More information, education, and communication directed at refugee communities; more donor support for supplies; and institutional commitment to train staff are needed to expand refugee access to EC.

  14. Active local volume displacement cancellation of a vibrating baffled beam

    NASA Astrophysics Data System (ADS)

    Zahui, Marcellin

    An active noise control apparatus is developed. The device reduces the sound radiated from a vibrating clamped beam. The attenuation of the sound field is obtained through minimization of local volume displacements of the vibrating beam. Two single- input/single-output cancellation devices are used. Each device employs a motion sensor and an acoustic actuator. The actuator is a loudspeaker equipped with a pressure sensor to detect its volume displacement. The motion sensor signal is related to the local volume displacement of the structure which is then reduced by a loudspeaker driven with an equal but opposing volume displacement. The volume displacement sensors are developed and fabricated using Polyvinylidene Fluoride (PVDF). They measure the local volume displacements of the vibrating beam. The pressure sensor is mounted in the loudspeaker enclosure. It provides the feedback signal for the loudspeaker volume displacement control. Previous work showed the successful implementation of this technique for uniformly vibrating radiators. This thesis presents the development of this technique for the reduction of sound radiated from a vibrating beam. First, a numerical local volume displacement cancellation experiment is performed using several loudspeakers, each canceling the volume displacement of a section of the beam. The finite element method is used to calculate the velocity distribution of the vibrating beam. A discretized form of the Rayleigh integral is then used to find the sound pressure and the sound power radiated before and after cancellation. Second, the numerical results are verified by laboratory experiments using a beam divided into two sections. Two motion sensors for the beam and one pressure sensor for each loudspeaker are fabricated and thoroughly checked. The cancellation experiment is then performed on a broadband random noise using two independent Proportional-Derivative (PD) controllers.

  15. Column test-rig facility for column scanning studies

    NASA Astrophysics Data System (ADS)

    Zain, Rasif M.; Roslan, Y.

    2010-03-01

    Distillation columns are considered as one of the most critical components in oil and gas plants. The plant performance depends on the ability of these columns to function as intended. Defective columns may lead to serious consequences to the plant operation, and hence the quality of product. In order to perform any inspection techniques to distillation column for NDT practitioner, the best facility was designed when the adjustable defeats of distillation column test rig has been developed. The paper discussed the development and the function of this facility.

  16. Column test-rig facility for column scanning studies

    NASA Astrophysics Data System (ADS)

    Zain, Rasif M.; Roslan, Y.

    2009-12-01

    Distillation columns are considered as one of the most critical components in oil and gas plants. The plant performance depends on the ability of these columns to function as intended. Defective columns may lead to serious consequences to the plant operation, and hence the quality of product. In order to perform any inspection techniques to distillation column for NDT practitioner, the best facility was designed when the adjustable defeats of distillation column test rig has been developed. The paper discussed the development and the function of this facility.

  17. Characteristics of acoustic emissions generated by drying front displacement in porous media

    NASA Astrophysics Data System (ADS)

    Grapsas, N. K.; Shokri, N.; Or, D.

    2011-12-01

    Fluid displacement fronts in porous media may produce acoustic emissions (AE) primarily due to rapid interfacial jumps at pore scale. We investigated acoustical signatures of propagating drying fronts in porous media during evaporation from Hele-Shaw cells packed with four types of sand, initially water saturated, with average particle sizes of 0.16 mm, 0.48 mm, 0.61 mm, and 1.76 mm. Evaporation rates were deduced from mass loss measured using digital balances. Evaporation experiments were conducted in an environmental chamber set to 35° C and 40% RH. An AE sensor was fixed to each glass column to monitor AEs associated with Haines jumps from a receding drying front. The characteristics of measured AEs such as amplitude, frequency, absolute energy, number of hits, and wave forms were recorded using an AE acquisition system. Preliminary results indicate a strong relationship between the cumulative number of AE hits and the columns' evaporative mass loss. Our results reveal that particle size significantly impacts the characteristics of the emitted acoustic waves. Larger particle sizes increase AE amplitudes, energies, and durations. Conversely, average hit frequency and the total number of hits are inversely related to particle size-- i.e. the smaller the particle size, the higher the frequency and total number of hits. These results suggest that AE techniques can be used to non-invasively characterize the texture of porous media and bring insights into their drying patterns.

  18. Oscillating water column structural model

    SciTech Connect

    Copeland, Guild; Bull, Diana L; Jepsen, Richard Alan; Gordon, Margaret Ellen

    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.

  19. Maximization of organic acids production by Aspergillus niger in a bubble column bioreactor for V and Ni recovery enhancement from power plant residual ash in spent-medium bioleaching experiments.

    PubMed

    Rasoulnia, P; Mousavi, S M

    2016-09-01

    Spent-medium bioleaching of V and Ni from a power plant residual ash (PPR ash) was conducted using organic acids produced by Aspergillus niger. The production of organic acids in a bubble column bioreactor was optimized through selecting three most influencing factors. Under optimum condition of aeration rate of 762.5(ml/min), sucrose concentration of 101.9(g/l) and inoculum size of 40(ml/l), respectively 17,185, 4539, 1042 and 502(ppm) of oxalic, gluconic, citric and malic acids were produced. Leaching experiments were carried out using biogenic produced organic acids under leaching environment temperature of 60°C and rotary shaking speed of 135rpm, with various pulp densities of 1, 2, 3, 5, 7 and 9(%w/v). The results showed that biogenic produced organic acids leached V much more efficiently than Ni so that even at high pulp density of 9(%w/v), 83% of V was recovered while Ni recovery yield was 30%. PMID:27295250

  20. Maximization of organic acids production by Aspergillus niger in a bubble column bioreactor for V and Ni recovery enhancement from power plant residual ash in spent-medium bioleaching experiments.

    PubMed

    Rasoulnia, P; Mousavi, S M

    2016-09-01

    Spent-medium bioleaching of V and Ni from a power plant residual ash (PPR ash) was conducted using organic acids produced by Aspergillus niger. The production of organic acids in a bubble column bioreactor was optimized through selecting three most influencing factors. Under optimum condition of aeration rate of 762.5(ml/min), sucrose concentration of 101.9(g/l) and inoculum size of 40(ml/l), respectively 17,185, 4539, 1042 and 502(ppm) of oxalic, gluconic, citric and malic acids were produced. Leaching experiments were carried out using biogenic produced organic acids under leaching environment temperature of 60°C and rotary shaking speed of 135rpm, with various pulp densities of 1, 2, 3, 5, 7 and 9(%w/v). The results showed that biogenic produced organic acids leached V much more efficiently than Ni so that even at high pulp density of 9(%w/v), 83% of V was recovered while Ni recovery yield was 30%.

  1. Job Displacement Among Single Mothers:

    PubMed Central

    Brand, Jennie E.; Thomas, Juli Simon

    2015-01-01

    Given the recent era of economic upheaval, studying the effects of job displacement has seldom been so timely and consequential. Despite a large literature associating displacement with worker well-being, relatively few studies focus on the effects of parental displacement on child well-being, and fewer still focus on implications for children of single parent households. Moreover, notwithstanding a large literature on the relationship between single motherhood and children’s outcomes, research on intergenerational effects of involuntary employment separations among single mothers is limited. Using 30 years of nationally representative panel data and propensity score matching methods, we find significant negative effects of job displacement among single mothers on children’s educational attainment and social-psychological well-being in young adulthood. Effects are concentrated among older children and children whose mothers had a low likelihood of displacement, suggesting an important role for social stigma and relative deprivation in the effects of socioeconomic shocks on child well-being. PMID:25032267

  2. Comparing Teaching Approaches About Maxwell's Displacement Current

    NASA Astrophysics Data System (ADS)

    Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício

    2014-08-01

    Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment relationship). Despite the consensus among physics educators concerning the relevance of the topic, there are many possible ways to interpret and justify the need for the displacement current term. With the goal of understanding the didactical transposition of this topic more deeply, we investigate three of its domains: (1) The historical development of Maxwell's reasoning; (2) Different approaches to justify the term insertion in physics textbooks; and (3) Four lectures devoted to introduce the topic in undergraduate level given by four different professors. By reflecting on the differences between these three domains, significant evidence for the knowledge transformation caused by the didactization of this episode is provided. The main purpose of this comparative analysis is to assist physics educators in developing an epistemological surveillance regarding the teaching and learning of the displacement current.

  3. Dual pressure displacement control system

    SciTech Connect

    Louis, J.E.; Klocke, C.C.

    1988-02-02

    This patent describes a dual pressure servo control system for a variable displacement hydraulic unit having displacement setting means positioned by a hydraulic servo mechanism. The hydraulic unit is provided with main loop lines at least one of which is capable of being subjected to high main loop pressure during operation of the hydraulic unit, a control line including a displacement control valve providing a controlled flow of fluid under pressure to the servo mechanism, and a source of fluid under pressure for the control line comprising a low pressure source connected to the control line through a check valve and high pressure source comprising of a high pressure control line connected to the control line downstream of the check valve. The high pressure control line includes a flow restriction limiting flow to the control line means and generating a significant flow induced pressure drop in the high pressure control line once movement in the servo mechanism is initiated.

  4. Gender-based violence in conflict and displacement: qualitative findings from displaced women in Colombia

    PubMed Central

    2014-01-01

    Introduction Gender-based violence (GBV) is prevalent among, though not specific to, conflict affected populations and related to multifarious levels of vulnerability of conflict and displacement. Colombia has been marked with decades of conflict, with an estimated 5.2 million internally displaced persons (IDPs) and ongoing violence. We conducted qualitative research to understand the contexts of conflict, displacement and dynamics with GBV. This as part of a multi-phase, mixed method study, in collaboration with UNHCR, to develop a screening tool to confidentially identify cases of GBV for referral among IDP women who were survivors of GBV. Methods Qualitative research was used to identify the range of GBV, perpetrators, contexts in conflict and displacement, barriers to reporting and service uptake, as well as to understand experiences of service providers. Thirty-five female IDPs, aged 18 years and older, who self-identified as survivors of GBV were enrolled for in-depth interviews in San Jose de Guaviare and Quibdo, Colombia in June 2012. Thirty-one service providers participated in six focus group discussions and four interviews across these sites. Results Survivors described a range of GBV across conflict and displacement settings. Armed actors in conflict settings perpetrated threats of violence and harm to family members, child recruitment, and, to a lesser degree, rape and forced abortion. Opportunistic violence, including abduction, rape, and few accounts of trafficking were more commonly reported to occur in the displacement setting, often perpetrated by unknown individuals. Intrafamilial violence, intimate partner violence, including physical and sexual violence and reproductive control were salient across settings and may be exacerbated by conflict and displacement. Barriers to reporting and services seeking were reported by survivors and providers alike. Conclusions Findings highlight the need for early identification of GBV cases, with emphasis on

  5. Perceived displacement explains wolfpack effect

    PubMed Central

    Šimkovic, Matúš; Träuble, Birgit

    2014-01-01

    We investigate the influence of perceived displacement of moving agent-like stimuli on the performance in dynamic interactive tasks. In order to reliably measure perceived displacement we utilize multiple tasks with different task demands. The perceived center of an agent's body is displaced in the direction in which the agent is facing and this perceived displacement is larger than the theoretical position of the center of mass would predict. Furthermore, the displacement in the explicit judgment is dissociated from the displacement obtained by the implicit measures. By manipulating the location of the pivot point, we show that it is not necessary to postulate orientation as an additional cue utilized by perception, as has been suggested by earlier studies. These studies showed that the agent's orientation influences the detection of chasing motion and the detection-related performance in interactive tasks. This influence has been labeled wolfpack effect. In one of the demonstrations of the wolfpack effect participants control a green circle on a display with a computer mouse. It has been shown that participants avoid display areas with agents pointing toward the green circle. Participants do so in favor of areas where the agents point in the direction perpendicular to the circle. We show that this avoidance behavior arises because the agent's pivot point selected by the earlier studies is different from where people locate the center of agent's body. As a consequence, the nominal rotation confounds rotation and translation. We show that the avoidance behavior disappears once the pivot point is set to the center of agent's body. PMID:25566114

  6. Particle displacement tracking for PIV

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.

    1990-01-01

    A new Particle Imaging Velocimetry (PIV) data acquisition and analysis system, which is an order of magnitude faster than any previously proposed system has been constructed and tested. The new Particle Displacement Tracing (PDT) system is an all electronic technique employing a video camera and a large memory buffer frame-grabber board. Using a simple encoding scheme, a time sequence of single exposure images are time coded into a single image and then processed to track particle displacements and determine velocity vectors. Application of the PDT technique to a counter-rotating vortex flow produced over 1100 velocity vectors in 110 seconds when processed on an 80386 PC.

  7. Rotor component displacement measurement system

    DOEpatents

    Mercer, Gary D.; Li, Ming C.; Baum, Charles R.

    2003-05-27

    A measuring system for measuring axial displacement of a tube relative to an axially stationary component in a rotating rotor assembly includes at least one displacement sensor adapted to be located normal to a longitudinal axis of the tube; an insulated cable system adapted for passage through the rotor assembly; a rotatable proximitor module located axially beyond the rotor assembly to which the cables are connected; and a telemetry system operatively connected to the proximitor module for sampling signals from the proximitor module and forwarding data to a ground station.

  8. Measurement of chest wall displacement based on terahertz wave

    NASA Astrophysics Data System (ADS)

    Li, Hui; Lv, Hao; Jiao, Teng; Lu, Guohua; Li, Sheng; Li, Zhao; Liu, Miao; Jing, Xijing; Wang, Jianqi

    2015-02-01

    Measurement of chest wall displacement is an important approach for measuring mechanics of chest wall, which has considerable significance for assessing respiratory system and diagnosing pulmonary diseases. However, existing optical methods for measuring chest wall displacement are inconvenient for some specific patients such as the female patients and the patients with bandaged chest. In this letter, we proposed a method for measuring chest wall displacement based on terahertz wave and established corresponding mathematic model and set up a terahertz measurement system. The main advantages of this method are that it can measure the chest wall displacement of the subjects without taking off clothes or arranging any markers. To validate this method and assess the performance of the terahertz system, in vitro, the displacement of a water module driven by a linear guide rail was measured by the terahertz system and compared with the actual displacement of the water module. The results showed that the waveforms measured with two methods have a good agreement, and the relative error is less than 5% and sufficiently good for measurement demands. In vivo, the synchronous experiment was performed on five human volunteers with the terahertz system and a respiratory belt transducer. The results demonstrate that this method has good performance and promising prospects for measuring chest wall displacement.

  9. The Role of Specific and General Human Capital after Displacement

    ERIC Educational Resources Information Center

    Kriechel, Ben; Pfann, Gerard A.

    2005-01-01

    Displaced workers experience significant and long-lasting wage losses. However, the average wage losses hide the tremendous differences among workers. So far, the differences are explained by differences in accumulated on-the-job experience, education level, age, and so on, but a large variation among similar workers remain. In this paper we…

  10. 20 CFR 627.230 - Displacement.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 3 2012-04-01 2012-04-01 false Displacement. 627.230 Section 627.230... PROGRAMS UNDER TITLES I, II, AND III OF THE ACT Program Requirements § 627.230 Displacement. (a) No currently employed worker shall be displaced by any participant (including partial displacement such as...

  11. 20 CFR 627.230 - Displacement.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Displacement. 627.230 Section 627.230... PROGRAMS UNDER TITLES I, II, AND III OF THE ACT Program Requirements § 627.230 Displacement. (a) No currently employed worker shall be displaced by any participant (including partial displacement such as...

  12. 20 CFR 627.230 - Displacement.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Displacement. 627.230 Section 627.230... PROGRAMS UNDER TITLES I, II, AND III OF THE ACT Program Requirements § 627.230 Displacement. (a) No currently employed worker shall be displaced by any participant (including partial displacement such as...

  13. Can Monkeys (Macaca mulatta) Represent Invisible Displacement?

    NASA Technical Reports Server (NTRS)

    Filion, Christine M.; Washburn, David A.; Gulledge, Jonathan P.

    1996-01-01

    Four experiments were conducted to assess whether or not rhesus macaques (Macaca mulatta) could represent the unperceived movements of a stimulus. Subjects were tested on 2 computerized tasks, HOLE (monkeys) and LASER (humans and monkeys), in which subjects needed to chase or shoot at, respectively, a moving target that either remained visible or became invisible for a portion of its path of movement. Response patterns were analyzed and compared between target-visible and target-invisible conditions. Results of Experiments 1, 2, and 3 demonstrated that the monkeys are capable of extrapolating movement. That this extrapolation involved internal representation of the target's invisible movement was suggested but not confirmed. Experiment 4, however, demonstrated that the monkeys are capable of representing the invisible displacements of a stimulus.

  14. SPIRAL CONTACTOR FOR SOLVENT EXTRACTION COLUMN

    DOEpatents

    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.

  15. Why Hexagonal Basalt Columns?

    PubMed

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

    2015-10-01

    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.

  16. Why Hexagonal Basalt Columns?

    PubMed

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

    2015-10-01

    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. PMID:26550724

  17. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul M.; Smith, Joseph G.

    1994-01-01

    Soluble polybenzimidazoles (PBI's) synthesized by nucleophilic displacement reaction of di(hydroxyphenyl)-benzimidazole monomers with activated aromatic difluoride compounds in presence of anhydrous potassium carbonate. These polymers exhibit good thermal, thermo-oxidative, and chemical stability, and high mechanical properties. Using benzimidazole monomers, more economical, and new PBI's processed more easily than commercial PBI, without loss of desirable physical properties.

  18. Displacement enzyme linked aptamer assay.

    PubMed

    Baldrich, Eva; Acero, Josep Lluis; Reekmans, Gunter; Laureyn, Wim; O'Sullivan, Ciara K

    2005-08-01

    Immense effort has been placed on the realization of immunoassays exploiting displacement of a suboptimum target, due to the ease of use and applicability to immunochromatographic strips and immunosensors. Most of the efforts reported to date focus on the use of a suboptimal target that is displaceable by the target toward which the antibody has higher affinity. Limited success has been achieved due to difficulty in obtaining suboptimal targets to which the antibody has enough affinity to bind while at the same time having lower levels of affinity in comparison to the target to facilitate displacement. Aptamers are synthetic oligonucleotides specifically selected to bind a certain target. Thanks to their high affinity and sensitivity, aptamers appear as alternative candidates to antibodies for analytical devices and several enzyme-linked aptamer assays and aptasensors have been reported. Aptamers, in contrast to antibodies, require the formation of a three-dimensional structure for target binding and can thus be anticipated to have a much higher affinity for binding its target rather than a modified form of the target (e.g., enzyme-labeled target). This phenomenon can be exploited for the development of a displacement assay, using enzyme-labeled target as a suboptimal displaceable molecule. Here, we report the first demonstration of the exploitation of an aptamer in an extremely rapid and highly sensitive displacement assay. Surface plasmon resonance studies demonstrated the thrombin-binding aptamer to have a lower affinity for enzyme-labeled thrombin than unmodified thrombin, with respective K(D) of 1.1 x 10(-8) and 2.9 x 10(-9) M. The assay is extremely rapid, requiring only 10 min for completion, and exhibits a detection limit lower than that obtainable with competitive enzyme-linked aptamer assays and comparable to that of hybrid aptamer-antibody assays. Optimal storage conditions for precoated microtiter plates (consisting of coated aptamer and captured

  19. Flow and displacement of Bingham plastics in porous media

    SciTech Connect

    Shah, C.B.; Kharabaf, H.; Yortsos, Y.C.

    1995-12-31

    Bingham plastics, which exhibit a finite yield stress at zero shear rate, have been used to model the flow behavior of certain heavy oils at reservoir conditions. In such fluids, the onset of flow and displacement occurs only after the applied pressure gradient exceeds a minimum value. Understanding the flow behavior of such fluids has been limited to phenomenological approaches. In this paper, we present numerical simulations and experimental visualization of flow and immiscible displacement of Bingham plastics in porous media using micromodels. First, we describe a novel pore network simulation approach to determine the onset of flow. The dependence of the critical yield stress on the pore-size distribution is discussed. Visualization experiments of the constant-rate immiscible displacement of Bingham plastics in glass micromodels and Hele-Shaw cells are next presented. The process is subsequently simulated in a pore network. Experiments are successfully simulated with the pore network model. We discuss the effect of the yield stress and injection rate on the displacement patterns. We also propose a classification of the displacement patterns, similar to that for Newtonian displacement.

  20. Analytical Modeling for the Grating Eddy Current Displacement Sensors

    NASA Astrophysics Data System (ADS)

    Lv, Chunfeng; Tao, Wei; Lei, Huaming; Jiang, Yingying; Zhao, Hui

    2015-02-01

    As a new type of displacement sensor, grating eddy current displacement sensor (GECDS) combines traditional eddy current sensors and grating structure in one. The GECDS performs a wide range displacement measurement without precision reduction. This paper proposes an analytical modeling approach for the GECDS. The solution model is established in the Cartesian coordinate system, and the solving domain is limited to finite extents by using the truncated region eigenfunction expansion method. Based on the second order vector potential, expressions for the electromagnetic field as well as coil impedance related to the displacement can be expressed in closed-form. Theoretical results are then confirmed by experiments, which prove the suitability and effectiveness of the analytical modeling approach.

  1. Effects of Displacement in Children Exposed to Disasters.

    PubMed

    Pfefferbaum, Betty; Jacobs, Anne K; Van Horn, Richard L; Houston, J Brian

    2016-08-01

    The literature on children's responses to disasters is well developed with increasing attention to the confounding experiences of displacement. This paper presents an overview of the emotional and behavioral effects of displacement on children and adolescents and describes their educational adjustment in terms of both academic achievement and school behavior. A summary of family effects elucidates how children's functioning is influenced through the family system in which they are embedded. The psychosocial impact of displacement reflects the myriad social losses that children and their families may face. Information from this review of the current literature on the effects of displacement may inform the design and delivery of support and intervention services for children and families following disasters. PMID:27287465

  2. Displacement measurements with resolution in the 15 pm range

    SciTech Connect

    Puppin, Ezio

    2005-10-15

    An approach to the measurement of mechanical displacements in the picometer range is proposed. The basic idea is to intercept a focused laser beam with a blade whose displacements induce a variation in the intensity of the transmitted light. The smallest detectable displacement depends on the beam diameter and on the resolution of the electronic chain. In our preliminary experiment the beam has been focused with a microscope objective down to a size of 3 {mu}m. Two different methods have been used for reducing noise in the electronic chain. In one case the output signal has been normalized to the laser intensity. In the other case the blade position has been modulated at low frequency. In both cases the smallest detectable displacement is in the order of 15 pm.

  3. Buckling of a holey column.

    PubMed

    Pihler-Puzović, D; Hazel, A L; Mullin, T

    2016-09-14

    We report the results from a combined experimental and numerical investigation of buckling in a novel variant of an elastic column under axial load. We find that including a regular line of centred holes in the column can prevent conventional, global, lateral buckling. Instead, the local microstructure introduced by the holes allows the column to buckle in an entirely different, internal, mode in which the holes are compressed in alternate directions, but the column maintains the lateral reflection symmetry about its centreline. The internal buckling mode can be accommodated within a smaller external space than the global one; and it is the preferred buckling mode over an intermediate range of column lengths for sufficiently large holes. For very short or sufficiently long columns a modification of the classical, global, lateral buckling is dominant. PMID:27501288

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

    PubMed

    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.

  5. Free displacer and Ringbom displacer for a Malone refrigerator

    SciTech Connect

    Swift, G.W.; Brown, A.O.

    1994-05-01

    Malone refrigeration uses a liquid near its critical point (instead of the customary gas) as the working fluid in a Stirling, Brayton, or similar regenerative or recuperative cycle. Thus far, we have focused on the Stirling cycle, to avoid the difficult construction of the high-pressure-difference counterflow recuperator required for a Brayton machine. Our first Malone refrigerator used liquid propylene (C{sub 3}H{sub 6}) in a double-acting 4-cylinder Stirling configuration. First measurements with a free displacer used in a liquid working fluid are presented. The displacer was operated both in harmonic mode and in Ringbom mode, in liquid carbon dioxide. The results are in reasonable agreement with expectations.

  6. Centrifuge Techniques and Apparatus for Transport Experiments in Porous Media

    SciTech Connect

    Earl D. Mattson; Carl D. Paler; Robert W. Smith; Markus Flury

    2010-06-01

    This paper describes experimental approaches and apparatus that we have developed to study solute and colloid transport in porous media using Idaho National Laboratory's 2-m radius centrifuge. The ex-perimental techniques include water flux scaling with applied acceleration at the top of the column and sub-atmospheric pressure control at the column base, automation of data collection, and remote experimental con-trol over the internet. These apparatus include a constant displacement piston pump, a custom designed liquid fraction collector based on switching valve technology, and modified moisture monitoring equipment. Suc-cessful development of these experimental techniques and equipment is illustrated through application to transport of a conservative tracer through unsaturated sand column, with centrifugal acceleration up to 40 gs. Development of such experimental equipment that can withstand high accelerations enhances the centrifuge technique to conduct highly controlled unsaturated solute/colloid transport experiments and allows in-flight liquid sample collection of the effluent.

  7. Compact electron beam focusing column

    SciTech Connect

    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.

  8. Some Considerations on Horizontal Displacement and Horizontal Displacement Coefficient B

    NASA Astrophysics Data System (ADS)

    Tajduś, Krzysztof; Tajduś, Antoni

    2015-12-01

    Mining-induced deformations of the ground surface and within the rock mass may pose danger not only for surface constructions but also for underground objects (e.g., tunnels, underground storages, garages), diverse types of pipelines, electric cables, etc. For a proper evaluation of hazard for surface and underground objects, such parameters as horizontal displacement and horizontal deformations, especially their maximum values, are of crucial importance. The paper is an attempt at a critical review of hitherto accomplished studies and state of the art of predicting horizontal displacement u, in particular the coefficient B, whose value allows determination of the value of maximum displacement if the value of maximum slope is known, or the value of maximum deformation if the value of maximum trough slope is recognized. Since the geodesic observations of fully developed subsidence troughs suggest that the value of the coefficient depends on the depth H, radius of main influences range r and properties of overburden rock, in particular the occurrence of sub-eras Paleogene and Neogene layers (old name: Quaternary and Tertiary) with low strength parameters, therefore a formula is provided in the present paper allowing for the estimation of the influence of those factors on the value of coefficient B.

  9. 45. MAIN MEETING ROOM COLUMNS. Ends of gallery columns identified ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    45. MAIN MEETING ROOM COLUMNS. Ends of gallery columns identified at the time of removal for transfer to the George School for re-erection. The stamp reads, 'REMOVED FROM 12th ST. MTG HSE PHILA 1972'. - Twelfth Street Meeting House, 20 South Twelfth Street, Philadelphia, Philadelphia County, PA

  10. DNAPL transport through macroporous, clayey till columns

    SciTech Connect

    Joergensen, P.R. |; Broholm, K.; Sonnenborg, T.O.; Arvin, E.

    1998-07-01

    This paper provides the first experimental determination of the rates and distribution of transport of a dense, nonaqueous phase liquid (DNAPL) through a naturally bioporous and fractured clayey till deposit. Until now, assessment of DNAPL behavior in this type of deposit has relied on theoretical studies. Predictions of DNAPL transport have proven to be uncertain as a result of difficulties in measuring critical parameters such as DNAPL entry pressure and flow behavior in response to natural fracture/biopore apertures and the degree of interconnection of these structures. In the present investigation, the migration of free product trichloroethylene (TCE) was studied by means of two undisturbed clayey till columns under in situ effective soil stress conditions. The experiments revealed that transport of TCE was restricted to biopores in one column and fractures in another column, bypassing the low-permeability clayey matrix. Effective porosities of the columns, i.e., biopores and fractures, were two to three orders of magnitude lower than total porosities, i.e., macropores and matrix. Single phase water flow rates through the columns at water-saturated conditions followed a linear relationship with hydraulic gradient. TCE flow could not be predicted from the single-phase calculations because of nonlinearity observed between applied TCE injection heads and resulting TCE flow. TCE flow rates were 24 and 10.3 m/day at TCE gradients of 1.18 and 0.91, respectively. The observed flow rates indicate that in cases where vertical biopores or fractures fully penetrate clayey till aquitards, a low-viscosity DNAPL may quickly enter underlying aquifers. The experiments further indicate that 100 liters of a low-viscosity DNAPL are sufficient to contaminate approximately 25 to 100 m{sup 3} of till material because of the small effective porosity constituted by the biopores and fractures.

  11. Multiple displacement motor driven power drive unit

    SciTech Connect

    Burandt, W. A.

    1985-12-03

    A multiple displacement motor driven power drive unit having two separate hydraulic systems each with a variable displacement hydraulic motor having its output connected to a torque summing gear train. A control provides for operation of one or the other of the motors at full displacement while the other motor is at zero displacement and free-wheels. There is a manual mechanical control operation with both motors simultaneously set at one-half of full displacement and driving the torque summing gear train. The change in motor displacements to one-half full displacement accomplishes velocity summing within the hydraulics. The multiple displacement motor driven power drive unit accomplishes the power efficiency of a multiple motor driven power drive unit utilizing a speed summing gear train with fixed displacement motors, but without the complexities associated with the use of a speed summing gear train and brakes.

  12. Dorsal column stimulator applications

    PubMed Central

    Yampolsky, Claudio; Hem, Santiago; Bendersky, Damián

    2012-01-01

    Background: Spinal cord stimulation (SCS) has been used to treat neuropathic pain since 1967. Following that, technological progress, among other advances, helped SCS become an effective tool to reduce pain. Methods: This article is a non-systematic review of the mechanism of action, indications, results, programming parameters, complications, and cost-effectiveness of SCS. Results: In spite of the existence of several studies that try to prove the mechanism of action of SCS, it still remains unknown. The mechanism of action of SCS would be based on the antidromic activation of the dorsal column fibers, which activate the inhibitory interneurons within the dorsal horn. At present, the indications of SCS are being revised constantly, while new applications are being proposed and researched worldwide. Failed back surgery syndrome (FBSS) is the most common indication for SCS, whereas, the complex regional pain syndrome (CRPS) is the second one. Also, this technique is useful in patients with refractory angina and critical limb ischemia, in whom surgical or endovascular treatment cannot be performed. Further indications may be phantom limb pain, chronic intractable pain located in the head, face, neck, or upper extremities, spinal lumbar stenosis in patients who are not surgical candidates, and others. Conclusion: Spinal cord stimulation is a useful tool for neuromodulation, if an accurate patient selection is carried out prior, which should include a trial period. Undoubtedly, this proper selection and a better knowledge of its underlying mechanisms of action, will allow this cutting edge technique to be more acceptable among pain physicians. PMID:23230533

  13. Polybenzimidazole via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G. (Inventor)

    1994-01-01

    Di(hydroxyphenyl)benzimidazole monomers were prepared from phenyl-4-hydroxybenzoate and aromatic bis(o-diamine)s. These monomers were used in the synthesis of soluble polybenzimidazoles. The reaction involved the aromatic nucleophilic displacement of various di(hydroxyphenyl)benzimidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds in the presence of an alkali metal base. These polymers exhibited lower glass transition temperatures, improved solubility, and better compression moldability over their commercial counterparts.

  14. Sorption, desorption and displacement of ibuprofen, estrone, and 17β estradiol in wastewater irrigated and rainfed agricultural soils.

    PubMed

    Durán-Álvarez, Juan C; Prado, Blanca; Ferroud, Anouck; Juayerk, Narcedalia; Jiménez-Cisneros, Blanca

    2014-03-01

    Sorption and leaching potential of ibuprofen, estrone and 17β estradiol were tested in two agricultural soils: one irrigated using municipal wastewater and the other used in rainfed agriculture. Batch sorption-desorption experiments and undisturbed soil column assays were carried out using both soils to which were added a mixture of the target compounds. The three compounds were sorbed to a different extent by both soils: estrone>17β estradiol>ibuprofen. Higher sorption was observed in the irrigated soil, which was attributed to the accumulation of organic matter caused by wastewater irrigation. Desorption of hormones was hysteretic in the irrigated soil, while ibuprofen showed low hysteresis in both soils. Retardation of the compounds' displacement was consistent with the sorption pattern observed in the batch tests. Retardation factor (RF) was similar for the three compounds in the two tested soils, indicating that the target compounds are much more mobile in the soil columns than would be predicted based on their equilibrium sorption parameters. The results obtained in the experiments clarify the role of wastewater irrigated soils as a filter and degradation media for the target micropollutants. PMID:24370693

  15. Analyze distillation columns with thermodynamics

    SciTech Connect

    Ognisty, T.P. )

    1995-02-01

    In a distillation column, heat supplies the work for separating the components of a feed stream into products. Distillation columns consume some 95% of the total energy used in separations. This amounts to roughly 3% of the energy consumed in the US. Since distillation is so energy intensive and requires significant capital outlays, an endless quest to improve the economics has continued since the beginning of the industry. By analyzing the thermodynamics of a distillation column, an engineer can quantify the thermodynamic efficiency of the process, identify the regions where energy can be better utilized, and define the minimum targets for energy consumption. This article reviews the principles of distillation column thermodynamics and outlines the analysis of lost work profiles and column heat profiles. It then illustrates these concepts through three examples.

  16. Exogenous factors contributing to column bed heterogeneity: Part 1: Consequences of 'air' injections in liquid chromatography.

    PubMed

    Samuelsson, Jörgen; Fornstedt, Torgny; Shalliker, Andrew

    2015-08-01

    It has been shown that not only the packing homogeneity, but also factors external to the column bed, such as, frits and distributors can have important effects on the column performance. This current communication is the first in a series focusing on the impact of exogenous factors on the column bed heterogeneity. This study is based on several observations by us and others that chromatographic runs often, for technical reasons, include more or less portions of air in the injections. It is therefore extremely important to find out the impact of air on the column performance, the reliability of the results derived from analyses where air was injected, and the effect on the column homogeneity. We used a photographic approach for visualising the air transport phenomena, and found that the air transport through the column is comprised of many different types of transport phenomena, such as laminal flow, viscous fingering like flows, channels and bulbs, and pulsations. More particularly, the air clouds within the column definitely interact in the adsorption, i.e. mobile phase adsorbed to the column surface is displaced. In addition, irrespective of the type of air transport phenomena, the air does not penetrate the column homogeneously. This process is strongly flow dependent. In this work we study air transport both in an analytical scale and a semi-prep column.

  17. Hysteretic behavior of special shaped columns composed of steel and reinforced concrete (SRC)

    NASA Astrophysics Data System (ADS)

    Chen, Zongping; Xu, Jinjun; Xue, Jianyang

    2015-06-01

    This paper describes a series of experimental investigations on seventeen specimens of steel reinforced concrete special shaped (SRCSS) columns under low cyclic reversed loading using parallel crosshead equipment. Nine T-shaped SRC columns, four L-shaped SRC columns and four +-shaped SRC columns were tested to examine the effects of shape steel configuration, loading angle, axial compressive ratio and shear-span ratio on the behavior (strength, stiffness, energy dissipation, ductility, etc.) of SRCSS column specimens. The failure modes and hysteretic performance of all the specimens were obtained in the tests. Test results demonstrate that the shear-span ratio is the main parameter affecting the failure modes of SRCSS columns. The specimens with small shear-span ratio are prone to shear failure, and the primary failure planes in SRCSS columns are parallel to the loading direction. As a result, there is a symmetry between positive and negative loading directions in the hysteretic curves of the SRCSS columns. The majority of displacement ductility coefficients for all the specimens are over 3.0, so that the SRCSS columns demonstrate a better deformation capacity. In addition, the equivalent viscous damping coefficients of all the specimens are greater than 0.2, indicating that the seismic behavior of SRCSS columns is adequate. Finally, the superposition theory was used to calculate the limits of axial compressive ratio for the specimens, and it is found that the test axial compressive ratio is close to or smaller than the calculated axial compressive ratio limit.

  18. What School District Administrators Should Know about the Educational Rights of Children Displaced by Disasters. Connecting Schools and Displaced Students Series, Winter 2006

    ERIC Educational Resources Information Center

    National Center for Homeless Education at SERVE, 2006

    2006-01-01

    School offers structure, stability, and support to children and youth displaced by disasters. The 2005 Gulf Coast hurricanes demonstrated the powerful role that schools can play in helping displaced children overcome the traumas they experience and regain their academic, social, and emotional footing. The school response to the 2005 hurricanes…

  19. Solute transport through large uniform and layered soil columns

    NASA Astrophysics Data System (ADS)

    Porro, I.; Wierenga, P. J.; Hills, R. G.

    1993-04-01

    Solute transport experiments are often conducted with homogeneous soils, whereas transport in real situations takes place in heterogeneous soils. An experiment was conducted to compare unsaturated solute transport through uniform and layered soils. Pulse inputs of tritiated water, bromide and chloride were applied under steady flow conditions to the tops of two large (0.95 m diameter by 6 m deep) soil columns. One column was uniformly filled with loamy fine sand and the other filled with alternating 20-cm-thick layers of loamy fine sand and silty clay loam. Soil solution samples were collected during the experiment with suction candles installed at various depths in the columns. Solute transport parameters were estimated by fitting the convection-dispersion equation to the observed breakthrough curves for each solute at various depths in each column. The match between the resulting calibrated curves and the experiment was better for the layered soil column than for the uniform soil column. The results displayed no clear relationship between the dispersion coefficients and depth for any of the tracers for either column. However, dispersivities were greater in the uniform column (3.5 cm) than in the layered column (1.2 cm), while retardation factors for bromide and chloride were similar (0.8 and 0.83, respectively, for the uniform and layered columns). A retardation factor less than one is attributed to anion exclusion. There was evidence of preferential flow in the uniform soil column. The peak concentrations at 5 m depth were greater than those observed at 4 m. Such behavior is inconsistent with one-dimensional flow. Similar results were observed in an experiment performed 3.5 years earlier using the same soil column and approximately the same flow rates, but using a different tracer and associated chemical analysis, different soil saturation prior to the execution of the experiment, and different experimental personnel. This supports the thesis that the anomalous

  20. A novel approach to modeling unstable EOR displacements. Final report

    SciTech Connect

    Peters, E.J.

    1994-04-01

    Most enhanced oil recovery schemes involve the displacement of a more dense and more viscous oil by a less dense and less viscous fluid in a heterogeneous porous medium. The interaction of heterogeneity with the several competing forces, namely, viscous, capillary, gravitational, and dispersive forces, can conspire to make the displacements unstable and difficult to model and to predict. The objective of this research was to develop a systematic methodology for modeling unstable fluid displacements in heterogeneous media. Flow visualization experiments were conducted using X-ray computed tomography imaging and a video imaging workstation to gain insights into the dynamics of unstable displacements, acquire detailed quantitative experimental image data for calibrating numerical models of unstable displacements, and image and characterize heterogeneities in laboratory cores geostatistically. High-resolution numerical models modified for use on vector-architecture supercomputers were used to replicate the image data. Geostatistical models of reservoir heterogeneity were incorporated in order to study the interaction of hydrodynamic instability and heterogeneity in reservoir displacements. Finally, a systematic methodology for matching the experimental data with the numerical models and scaling the laboratory results to other systems were developed. The result is a new method for predicting the performance of unstable EOR displacements in the field based on small-scale displacements in the laboratory. The methodology is general and can be applied to forecast the performance of most processes that involve fluid flow and transport in porous media. Therefore, this research should be of interest to those involved in forecasting the performance of enhanced oil recovery processes and the spreading of contaminants in heterogeneous aquifers.

  1. Mush Column Magma Chambers

    NASA Astrophysics Data System (ADS)

    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

  2. Stiffening of short small-size circular composite steel-concrete columns with shear connectors.

    PubMed

    Younes, Sherif M; Ramadan, Hazem M; Mourad, Sherif A

    2016-05-01

    An experimental program was conducted to investigate the effect of shear connectors' distribution and method of load application on load-displacement relationship and behavior of thin-walled short concrete-filled steel tube (CFT) columns when subjected to axial load. The study focused on the compressive strength of the CFT columns and the efficiency of the shear stud in distribution of the load between the concrete core and steel tube. The study showed that the use of shear connectors enhanced slightly the axial capacity of CFT columns. It is also shown that shear connectors have a great effect on load distribution between the concrete and steel tubes.

  3. Stiffening of short small-size circular composite steel–concrete columns with shear connectors

    PubMed Central

    Younes, Sherif M.; Ramadan, Hazem M.; Mourad, Sherif A.

    2015-01-01

    An experimental program was conducted to investigate the effect of shear connectors’ distribution and method of load application on load–displacement relationship and behavior of thin-walled short concrete-filled steel tube (CFT) columns when subjected to axial load. The study focused on the compressive strength of the CFT columns and the efficiency of the shear stud in distribution of the load between the concrete core and steel tube. The study showed that the use of shear connectors enhanced slightly the axial capacity of CFT columns. It is also shown that shear connectors have a great effect on load distribution between the concrete and steel tubes. PMID:27222757

  4. Microbial activity in weathering columns.

    PubMed

    García, C; Ballester, A; González, F; Blázquez, M L

    2007-03-22

    The aim of the present work was to evaluate the metabolic activity of the microbial population associated with a pyritic tailing after a column-weathering test. For this purpose, a column 150cm high and 15cm diameter was used. The solid was a tailing with 63.4% pyrite and with minor amounts of Cu, Pb and Zn sulfides (1.4, 0.5 and 0.8%, respectively). The column model was the habitual one for weathering tests: distilled water was added at the top of the column; the water flowed down through tailings and finally was collected at the bottom for chemical and microbiological analysis. Weathering was maintained for 36 weeks. The results showed a significant presence of microbial life that was distributed selectively over the column: sulfur- and iron-oxidizing aerobic bacteria were in the more oxygenated zone; anaerobic sulfur-reducing bacteria were isolated from the samples taken from the anoxic part of the column. Activity testing showed that (oxidizing and reducing) bacteria populations were active at the end of the weathering test. The quality of the water draining from the column was thus the final product of biological oxidation and reduction promoted by the bacteria consortia.

  5. The case for character displacement in plants

    PubMed Central

    Beans, Carolyn M

    2014-01-01

    The evidence for character displacement as a widespread response to competition is now building. This progress is largely the result of the establishment of rigorous criteria for demonstrating character displacement in the animal literature. There are, however, relatively few well-supported examples of character displacement in plants. This review explores the potential for character displacement in plants by addressing the following questions: (1) Why aren't examples of character displacement in plants more common? (2) What are the requirements for character displacement to occur and how do plant populations meet those requirements? (3) What are the criteria for testing the pattern and process of character displacement and what methods can and have been used to address these criteria in the plant literature? (4) What are some additional approaches for studying character displacement in plants? While more research is needed, the few plant systems in which character displacement hypotheses have been rigorously tested suggest that character displacement may play a role in shaping plant communities. Plants are especially amenable to character displacement studies because of the experimental ease with which they can be used in common gardens, selection analyses, and breeding designs. A deeper investigation of character displacement in plants is critical for a more complete understanding of the ecological and evolutionary processes that permit the coexistence of plant species. PMID:24683467

  6. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Engine displacement. 205.153 Section... TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the nearest whole cubic...

  7. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Engine displacement. 205.153 Section... TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the nearest whole cubic...

  8. 25 CFR 700.59 - Displaced person.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Displaced person. 700.59 Section 700.59 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES General Policies and Instructions Definitions § 700.59 Displaced person. Displaced person means a member of the Hopi Tribe residing within the area partitioned...

  9. 25 CFR 700.59 - Displaced person.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Displaced person. 700.59 Section 700.59 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES General Policies and Instructions Definitions § 700.59 Displaced person. Displaced person means a member of the Hopi Tribe residing within the area partitioned...

  10. 25 CFR 700.59 - Displaced person.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Displaced person. 700.59 Section 700.59 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES General Policies and Instructions Definitions § 700.59 Displaced person. Displaced person means a member of the Hopi Tribe residing within the area partitioned...

  11. 25 CFR 700.59 - Displaced person.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false Displaced person. 700.59 Section 700.59 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES General Policies and Instructions Definitions § 700.59 Displaced person. Displaced person means a member of the Hopi Tribe residing within the area partitioned...

  12. 25 CFR 700.59 - Displaced person.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Displaced person. 700.59 Section 700.59 Indians THE OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES General Policies and Instructions Definitions § 700.59 Displaced person. Displaced person means a member of the Hopi Tribe residing within the area partitioned...

  13. The case for character displacement in plants.

    PubMed

    Beans, Carolyn M

    2014-03-01

    The evidence for character displacement as a widespread response to competition is now building. This progress is largely the result of the establishment of rigorous criteria for demonstrating character displacement in the animal literature. There are, however, relatively few well-supported examples of character displacement in plants. This review explores the potential for character displacement in plants by addressing the following questions: (1) Why aren't examples of character displacement in plants more common? (2) What are the requirements for character displacement to occur and how do plant populations meet those requirements? (3) What are the criteria for testing the pattern and process of character displacement and what methods can and have been used to address these criteria in the plant literature? (4) What are some additional approaches for studying character displacement in plants? While more research is needed, the few plant systems in which character displacement hypotheses have been rigorously tested suggest that character displacement may play a role in shaping plant communities. Plants are especially amenable to character displacement studies because of the experimental ease with which they can be used in common gardens, selection analyses, and breeding designs. A deeper investigation of character displacement in plants is critical for a more complete understanding of the ecological and evolutionary processes that permit the coexistence of plant species.

  14. Displacement Compensation of Temperature Probe Data

    NASA Technical Reports Server (NTRS)

    Welch, Christopher S.; Hubert, James A.; Barber, Patrick G.

    1996-01-01

    Analysis of temperature data from a probe in a vertical Bridgman furnace growing germanium crystals revealed a displacement of the temperature profile due to conduction error. A theoretical analysis shows that the displacement compensation is independent of local temperature gradient. A displacement compensation value should become a standard characteristic of temperature probes used for temperature profile measurements.

  15. Displaced Children: The Psychological Implications.

    PubMed

    Joshi, Paramjit T; Fayyad, John A

    2015-10-01

    Millions of people across the world have been displaced or live in exile and/or as refugees largely as a consequence of wars, acts of terrorism, and catastrophic natural disasters. There are serious psychological consequences as a result of these extremely difficult life circumstances. Adults often can express their needs and have them be heard, whereas children are unable to do so. The children may be provided food, shelter, and clothing and have their medical needs attended to, but their emotional and psychological needs go unrecognized and unmet, with dire and monumental long-term consequences. PMID:26346385

  16. Displacement Current and Surface Flashover

    SciTech Connect

    harris, J R; Caporaso, G J; Blackfield, D; Chen, Y J

    2007-07-17

    High-voltage vacuum insulator failure is generally due to surface flashover rather than insulator bulk breakdown. Vacuum surface flashover is widely believed to be initiated by a secondary electron emission avalanche along the vacuum-insulator interface. This process requires a physical mechanism to cause secondary electrons emitted from the insulator surface to return to that surface. Here, we show that when an insulator is subjected to a fast high-voltage pulse, the magnetic field due to displacement current through the insulator can provide this mechanism. This indicates the importance of the voltage pulse shape, especially the rise time, in the flashover initiation process.

  17. Optimal design of thermally coupled distillation columns

    SciTech Connect

    Duennebier, G.; Pantelides, C.C.

    1999-01-01

    This paper considers the optimal design of thermally coupled distillation columns and dividing wall columns using detailed column models and mathematical optimization. The column model used is capable of describing both conventional and thermally coupled columns, which allows comparisons of different structural alternatives to be made. Possible savings in both operating and capital costs of up to 30% are illustrated using two case studies.

  18. Mining Induced Displacement and Mental Health: A Call for Action

    ERIC Educational Resources Information Center

    Goessling, Kristen P.

    2010-01-01

    India is a country of unparalleled diversity within both the cultural and ecological spheres of life. This paper examines the author's experience exploring and inquiring into the mental health implications of mining and mining induced displacement within several Adivasi (tribal) communities in Andhra Pradesh, India. Through collaboration with…

  19. Armed conflict, homonegativity, and forced internal displacement: Implications for HIV among Colombian gay, bisexual, and transgender individuals

    PubMed Central

    Reisen, Carol A.; Bianchi, Fernanda T.; Gonzales, Felisa A.; Betancourt, Fabián; Aguilar, Marcela; Poppen, Paul J.

    2013-01-01

    Colombia has endured six decades of civil unrest, population displacement, and violence. We examined the relationships of contextual conditions, displacement, and HIV among gay, bisexual, and transgender individuals in Bogotá, Colombia. Nineteen key informants provided information about internal displacement of sexual minorities. Life history interviews were conducted with 42 participants aged 18 to 48 years, and included questions about displacement experiences, sexual behaviour, life prior to displacement, and participants’ economic and social situation in Bogotá. The interplay of a variety of factors—including internal conflict and violence, homonegativity and “social cleansing,” gender and sexual identity, and poverty—strongly shaped the varied experiences of displacement. Migration, sexual violence, exchange sex, and low rates of HIV testing were risk factors that increased vulnerability for HIV in this displaced sample. Although displacement and HIV in Colombia are major problems, both are understudied. PMID:23586420

  20. Armed conflict, homonegativity and forced internal displacement: implications for HIV among Colombian gay, bisexual and transgender individuals.

    PubMed

    Zea, Maria Cecilia; Reisen, Carol A; Bianchi, Fernanda T; Gonzales, Felisa A; Betancourt, Fabián; Aguilar, Marcela; Poppen, Paul J

    2013-01-01

    Colombia has endured six decades of civil unrest, population displacement and violence. We examined the relationships between contextual conditions, displacement and HIV among gay, bisexual and transgender individuals in Bogotá, Colombia. A total of 19 key informants provided information about internal displacement of sexual minorities. Life-history interviews were conducted with 42 participants aged 18 to 48 years and included questions about displacement experiences, sexual behaviour, life prior to displacement and participants' economic and social situation in Bogotá. The interplay of a variety of factors - including internal conflict and violence, homonegativity and 'social cleansing', gender and sexual identity and poverty - strongly shaped the varied experiences of displacement. Migration, sexual violence, exchange sex and low rates of HIV testing were risk factors that increased vulnerability for HIV in this displaced sample. Although displacement and HIV in Colombia are major problems, both are understudied. PMID:23586420

  1. Armed conflict, homonegativity and forced internal displacement: implications for HIV among Colombian gay, bisexual and transgender individuals.

    PubMed

    Zea, Maria Cecilia; Reisen, Carol A; Bianchi, Fernanda T; Gonzales, Felisa A; Betancourt, Fabián; Aguilar, Marcela; Poppen, Paul J

    2013-01-01

    Colombia has endured six decades of civil unrest, population displacement and violence. We examined the relationships between contextual conditions, displacement and HIV among gay, bisexual and transgender individuals in Bogotá, Colombia. A total of 19 key informants provided information about internal displacement of sexual minorities. Life-history interviews were conducted with 42 participants aged 18 to 48 years and included questions about displacement experiences, sexual behaviour, life prior to displacement and participants' economic and social situation in Bogotá. The interplay of a variety of factors - including internal conflict and violence, homonegativity and 'social cleansing', gender and sexual identity and poverty - strongly shaped the varied experiences of displacement. Migration, sexual violence, exchange sex and low rates of HIV testing were risk factors that increased vulnerability for HIV in this displaced sample. Although displacement and HIV in Colombia are major problems, both are understudied.

  2. Topographic and quantitative description of rat dorsal column fibres arising from the lumbar dorsal roots.

    PubMed

    Smith, K J; Bennett, B J

    1987-08-01

    The number and topographic distribution of the profiles of degenerating primary afferent fibres were determined within the rat dorsal column 3-4 weeks after division of the lumbar and S2 dorsal roots. The degenerating fibres were identified in toluidine blue-stained 1 micron transverse sections taken at different spinal levels, and their positions were marked with the aid of a drawing tube. Fibres entered the dorsal column at its lateral margin and sent projections rostrally and caudally. Fibres ascending the column were displaced medially in an orderly progression as the fibres of more rostral roots entered the cord. Most ascending fibres were lost from the dorsal columns within 2-3 segments of their site of entry, with only 15%, on average, reaching cervical levels. The descending fibres maintained a less organised topographic distribution, and typically only 3% of fibres entering the dorsal column descended two segments from their site of entry.

  3. Direct conversion of silver complexes to nanoscale hexagonal columns on a copper alloy for plasmonic applications.

    PubMed

    Yamamoto, Yuko S; Hasegawa, Katsuyuki; Hasegawa, Yuuki; Takahashi, Naoshi; Kitahama, Yasutaka; Fukuoka, Satoshi; Murase, Norio; Baba, Yoshinobu; Ozaki, Yukihiro; Itoh, Tamitake

    2013-09-21

    We introduced a novel method for the rapid synthesis of silver nanohexagonal thin columns from an aqueous mixture of sodium thiosulfate (Na2S2O3) and silver chloride (AgCl) simply added to a phosphor bronze substrate. The reaction is based on galvanic displacement and the products are potentially useful for plasmonic applications.

  4. Continual in-plane displacement measurement with temporal wavelet transform speckle pattern interferometry.

    PubMed

    Gao, Zhan; Deng, Yan; Duan, Yiting; Zhang, Zhifeng; Wei, Cheng; Chen, Shiqian; Cui, Jianying; Feng, Qibo

    2012-01-01

    A heterodyne temporal speckle pattern interferometer that measures the in-plane displacement dynamically has been built. The object is displaced in its plane continuously and the frequency-modulated output signals with a carrier frequency are recorded by a CCD camera. The displacement information is extracted with wavelet transform technique. Preliminary experiments have been performed with such interferometer. The respective measurement results recovered from wavelet transform and Fourier transform are compared.

  5. Superconducting inductive displacement detection of a microcantilever

    SciTech Connect

    Vinante, A.

    2014-07-21

    We demonstrate a superconducting inductive technique to measure the displacement of a micromechanical resonator. In our scheme, a type I superconducting microsphere is attached to the free end of a microcantilever and approached to the loop of a dc Superconducting Quantum Interference Device (SQUID) microsusceptometer. A local magnetic field as low as 100 μT, generated by a field coil concentric to the SQUID, enables detection of the cantilever thermomechanical noise at 4.2 K. The magnetomechanical coupling and the magnetic spring are in good agreement with image method calculations assuming pure Meissner effect. These measurements are relevant to recent proposals of quantum magnetomechanics experiments based on levitating superconducting microparticles.

  6. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, John

    1995-01-01

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

  7. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, John

    1999-01-01

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

  8. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, J.

    1995-05-30

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 29 figs.

  9. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, J.

    1999-04-06

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 23 figs.

  10. Self-regenerating column chromatography

    DOEpatents

    Park, Woo K.

    1995-05-30

    The present invention provides a process for treating both cations and anions by using a self-regenerating, multi-ionic exchange resin column system which requires no separate regeneration steps. The process involves alternating ion-exchange chromatography for cations and anions in a multi-ionic exchange column packed with a mixture of cation and anion exchange resins. The multi-ionic mixed-charge resin column works as a multi-function column, capable of independently processing either cationic or anionic exchange, or simultaneously processing both cationic and anionic exchanges. The major advantage offered by the alternating multi-function ion exchange process is the self-regeneration of the resins.

  11. Fiber optic displacement measurement model based on finite reflective surface

    NASA Astrophysics Data System (ADS)

    Li, Yuhe; Guan, Kaisen; Hu, Zhaohui

    2016-10-01

    We present a fiber optic displacement measurement model based on finite reflective plate. The theoretical model was derived, and simulation analysis of light intensity distribution, reflective plate width, and the distance between fiber probe and reflective plate were conducted in details. The three dimensional received light intensity distribution and the characteristic curve of light intensity were studied as functions of displacement of finite reflective plate. Experiments were carried out to verify the established model. The physical fundamentals and the effect of operating parameters on measuring system performance were revealed in the end.

  12. LIQUID-LIQUID EXTRACTION COLUMNS

    DOEpatents

    Thornton, J.D.

    1957-12-31

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

  13. A theoretical model to predict both horizontal displacement and vertical displacement for electromagnetic induction-based deep displacement sensors.

    PubMed

    Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

    2012-01-01

    Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors' mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors' monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency.

  14. A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors

    PubMed Central

    Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

    2012-01-01

    Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors’ mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors’ monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency. PMID:22368467

  15. An Optical Fiber Displacement Sensor Using RF Interrogation Technique.

    PubMed

    Kim, Hyeon-Ho; Choi, Sang-Jin; Jeon, Keum Soo; Pan, Jae-Kyung

    2016-02-24

    We propose a novel non-contact optical fiber displacement sensor. It uses a radio frequency (RF) interrogation technique which is based on bidirectional modulation of a Mach-Zehnder electro-optical modulator (MZ-EOM). The displacement is measured from the free spectral range (FSR) which is determined by the dip frequencies of the modulated MZ-EOM transfer function. In experiments, the proposed sensor showed a sensitivity of 456 kHz/mm or 1.043 kHz/V in a measurement range of 7 mm. The displacement resolution of the proposed sensor depends on the linewidth and the power of the optical source. Resolution better than 0.05 μm would be achieved if an optical source which has a linewidth narrower than 1.5 nm and a received power larger than -36 dBm is used. Also, the multiplexing characteristic of the proposed sensor was experimentally validated.

  16. An Optical Fiber Displacement Sensor Using RF Interrogation Technique.

    PubMed

    Kim, Hyeon-Ho; Choi, Sang-Jin; Jeon, Keum Soo; Pan, Jae-Kyung

    2016-01-01

    We propose a novel non-contact optical fiber displacement sensor. It uses a radio frequency (RF) interrogation technique which is based on bidirectional modulation of a Mach-Zehnder electro-optical modulator (MZ-EOM). The displacement is measured from the free spectral range (FSR) which is determined by the dip frequencies of the modulated MZ-EOM transfer function. In experiments, the proposed sensor showed a sensitivity of 456 kHz/mm or 1.043 kHz/V in a measurement range of 7 mm. The displacement resolution of the proposed sensor depends on the linewidth and the power of the optical source. Resolution better than 0.05 μm would be achieved if an optical source which has a linewidth narrower than 1.5 nm and a received power larger than -36 dBm is used. Also, the multiplexing characteristic of the proposed sensor was experimentally validated. PMID:26927098

  17. Polymeric nanospheres as a displacement fluid in enhanced oil recovery

    NASA Astrophysics Data System (ADS)

    Hendraningrat, Luky; Zhang, Julien

    2015-11-01

    This paper presents the investigation of using nanoscale polyacrylamide-based spheres (nanospheres) as a displacement fluid in enhanced oil recovery (EOR). Coreflood experiments were conducted to evaluate the impact of nanospheres and its concentration dispersed in model formation water on oil recovery during a tertiary oil recovery process. The coreflood results showed that nanospheres can enhance residual oil recovery in the sandstone rock samples and its concentration showed a significant impact into incremental oil. By evaluating the contact angle, it was observed that wettability alteration also might be involved in the possible oil displacement mechanism in this process together with fluid behavior and permeability to water that might divert injected fluid into unswept oil areas and enhance the residual oil recovery. These investigations promote nanospheres aqueous disperse solution as a potential displacement fluid in EOR.

  18. In-plane displacement measurement using optical vortex phase shifting.

    PubMed

    Sun, Haibin; Wang, Xinghai; Sun, Ping

    2016-07-20

    In this paper, we propose a new method for in-plane displacement measurement by application of phase shifting based on an optical vortex. The phase shifts are obtained by displaying computer-generated fork holograms on the screen of a liquid-crystal spatial light modulator (LC-SLM). Furthermore, the vortex beam that is generated by the LC-SLM can be used as a reference light in the experiment. Eight speckle patterns with phase-shift increments of 0, π/2, π, and 3π/2 were captured by a CCD camera before and after the deformation. The displacement of the deformed object was obtained by unwrapping. Experimental results demonstrated the efficacy of the proposed method for in-plane displacement measurement. PMID:27463914

  19. Micro-stress dominant displacive reconstructive transition in lithium aluminate

    NASA Astrophysics Data System (ADS)

    Hu, Qiwei; Lei, Li; Yan, Xiaozhi; Zhang, Leilei; Li, Xiaodong; Peng, Fang; He, Duanwei

    2016-08-01

    It is supposed that diffusive reconstructive transitions usually take place under hydrostatic pressure or low stresses, and displacive reconstructive phase transitions easily occur at nonhydrostatic pressure. Here, by in-situ high pressure synchrotron X-ray diffraction and single-crystal Raman scattering studies on lithium aluminate at room temperature, we show that the reconstructive transition mechanism is dependent on the internal microscopic stresses rather than the macroscopic stresses. In this case, even hydrostatic pressure can favor the displacive transition if the compressibility of crystal is anisotropic. During hydrostatic compression, γ-LiAlO2 transforms to δ-LiAlO2 at about 4 GPa, which is much lower than that in previous nonhydrostatic experiments (above 9 GPa). In the region where both phases coexist, there are enormous microscopic stresses stemming from the lattice mismatch, suggesting that this transition is displacive. Furthermore, the atomic picture is drawn with the help of the shear Raman modes.

  20. An Optical Fiber Displacement Sensor Using RF Interrogation Technique

    PubMed Central

    Kim, Hyeon-Ho; Choi, Sang-Jin; Jeon, Keum Soo; Pan, Jae-Kyung

    2016-01-01

    We propose a novel non-contact optical fiber displacement sensor. It uses a radio frequency (RF) interrogation technique which is based on bidirectional modulation of a Mach-Zehnder electro-optical modulator (MZ-EOM). The displacement is measured from the free spectral range (FSR) which is determined by the dip frequencies of the modulated MZ-EOM transfer function. In experiments, the proposed sensor showed a sensitivity of 456 kHz/mm or 1.043 kHz/V in a measurement range of 7 mm. The displacement resolution of the proposed sensor depends on the linewidth and the power of the optical source. Resolution better than 0.05 μm would be achieved if an optical source which has a linewidth narrower than 1.5 nm and a received power larger than −36 dBm is used. Also, the multiplexing characteristic of the proposed sensor was experimentally validated. PMID:26927098

  1. Deformation Monitoring of Retrofitted Short Concrete Columns with Laser Sensor

    NASA Astrophysics Data System (ADS)

    Avsar, E. Ö.; Celik, M. F.; Binbir, E.; Arslan, A. E.; Çokkeçeci, D.; Seker, D. Z.; Pala, S.

    2016-06-01

    This paper presents one of the applications of monitoring mechanical tests carried out in Construction Materials Laboratory of Istanbul Technical University. In Turkey, as in many countries, large amount of existing buildings exposed to seismic hazard, therefore various analytical and experimental studies are being conducted to contribute to the solution of the problem. One of the new generation retrofitting techniques is to strength the structural members by using Fiber Reinforcing Polymer (FRP). This study summarize the results of monitoring of deformations short concrete column samples under the incremental compression load. In this study, result of two rectangular short columns are given. One of them was tested as a reference sample, the other sample were tested after strengthening by PET reinforced polymer composite materials. Besides conventional displacement and strain measurement systems, laser scanning method was used to get three dimensional deformed shape of sample at each selected steps.

  2. Linking pollination effectiveness and interspecific displacement success in bees.

    PubMed

    Ali, M; Saeed, S; Sajjad, A; Akbar, A

    2015-04-01

    Pollen deposition, a surrogate for bee efficiency, becomes increasingly important during their interspecific interactions. We conducted field experiments on highly cross-pollinated melon (Cucumis melo) and watermelon (Citrullus lanatus) in order to understand how bee species with different pollination efficiencies displace each other from floral resources. We observed significant displacement of less abundant but more efficient bees by the more abundant but less efficient bees in both crops, which may lead to deficient pollination. We did not find significant relationship of the bee displacement success and body size or abundance. Apis florea (Fabricius) and Nomia sp.2 (Latreille) had significantly more winner events in melon, while the former also had significantly more winner events in watermelon. A. florea was the only bee species that foraged mostly within the 1-m(2) virtual area after their displacement, which may indicate its behavior of geitinogamous pollination. The two bee species, Ceratina sexmaculata (Smith) and Lasioglossum sp. (Curtis), were more sensitive to displacement as their proportion of leaving the 1-m(2) virtual area was higher. PMID:26013126

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

    PubMed

    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. PMID:26983917

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

    PubMed

    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.

  5. Displaceable Gear Torque Controlled Driver

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (Inventor)

    1997-01-01

    Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

  6. Variable delivery, fixed displacement pump

    DOEpatents

    Sommars, Mark F.

    2001-01-01

    A variable delivery, fixed displacement pump comprises a plurality of pistons reciprocated within corresponding cylinders in a cylinder block. The pistons are reciprocated by rotation of a fixed angle swash plate connected to the pistons. The pistons and cylinders cooperate to define a plurality of fluid compression chambers each have a delivery outlet. A vent port is provided from each fluid compression chamber to vent fluid therefrom during at least a portion of the reciprocal stroke of the piston. Each piston and cylinder combination cooperates to close the associated vent port during another portion of the reciprocal stroke so that fluid is then pumped through the associated delivery outlet. The delivery rate of the pump is varied by adjusting the axial position of the swash plate relative to the cylinder block, which varies the duration of the piston stroke during which the vent port is closed.

  7. Polybenzimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1995-01-01

    Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl) benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl) benzimidazoles are synthesizedby reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  8. Displaced electrode process for welding

    DOEpatents

    Heichel, L.J.

    1975-08-26

    A method is described for the butt-welding of a relatively heavy mass to a relatively small mass such as a thin-wall tube. In butt-welding heat is normally applied at the joint between the two pieces which are butt-welded together. The application of heat at the joint results in overheating the tube which causes thinning of the tube walls and porosity in the tube material. This is eliminated by displacing the welding electrode away from the seam toward the heavier mass so that heat is applied to the heavy mass and not at the butt seam. Examples of the parameters used in welding fuel rods are given. The cladding and end plugs were made of Zircalloy. The electrode used was of 2 percent thoriated tungsten. (auth)

  9. Polyimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

    1991-01-01

    Polyimidazoles (Pl) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl)imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethylacetamide, sulfolane, N-methylpyrroldinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperature under nitrogen. The di(hydroxyphenyl)imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl)imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxyphenyl)imidazole monomer. This synthetic route has provided high molecular weight Pl of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  10. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergerrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1997-01-01

    Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenylbenzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl)benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl)benzimidazoles are synthesized by reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  11. Polyimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

    1992-01-01

    Polyimidazoles (PI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl) imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethyl acetamide, sulfolane, N-methylpyrrolidinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl) imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl) imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxphenyl) imidazole monomer. This synthetic route has provided high molecular weight PI of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  12. Water column methanotrophy controlled by a rapid oceanographic switch

    NASA Astrophysics Data System (ADS)

    Steinle, Lea; Graves, Carolyn A.; Treude, Tina; Ferré, Bénédicte; Biastoch, Arne; Bussmann, Ingeborg; Berndt, Christian; Krastel, Sebastian; James, Rachael H.; Behrens, Erik; Böning, Claus W.; Greinert, Jens; Sapart, Célia-Julia; Scheinert, Markus; Sommer, Stefan; Lehmann, Moritz F.; Niemann, Helge

    2015-05-01

    Large amounts of the greenhouse gas methane are released from the seabed to the water column, where it may be consumed by aerobic methanotrophic bacteria. The size and activity of methanotrophic communities, which determine the amount of methane consumed in the water column, are thought to be mainly controlled by nutrient and redox dynamics. Here, we report repeated measurements of methanotrophic activity and community size at methane seeps west of Svalbard, and relate them to physical water mass properties and modelled ocean currents. We show that cold bottom water, which contained a large number of aerobic methanotrophs, was displaced by warmer water with a considerably smaller methanotrophic community within days. Ocean current simulations using a global ocean/sea-ice model suggest that this water mass exchange is consistent with short-term variations in the meandering West Spitsbergen Current. We conclude that the shift from an offshore to a nearshore position of the current can rapidly and severely reduce methanotrophic activity in the water column. Strong fluctuating currents are common at many methane seep systems globally, and we suggest that they affect methane oxidation in the water column at other sites, too.

  13. Whose Cortical Column Would that Be?

    PubMed Central

    da Costa, Nuno Maçarico; Martin, Kevan A. C.

    2010-01-01

    The cortical column has been an invaluable concept to explain the functional organization of the neocortex. While this idea was born out of experiments that cleverly combined electrophysiological recordings with anatomy, no one has ‘seen’ the anatomy of a column. All we know is that when we record through the cortex of primates, ungulates, and carnivores in a trajectory perpendicular to its surface there is a remarkable constancy in the receptive field properties of the neurons regarding one set of stimulus features. There is no obvious morphological analog for this functional architecture, in fact much of the anatomical data seems to challenge it. Here we describe historically the origins of the concept of the cortical column and the struggles of the pioneers to define the columnar architecture. We suggest that in the concept of a ‘canonical circuit’ we may find the means to reconcile the structure of neocortex with its functional architecture. The canonical microcircuit respects the known connectivity of the neocortex, and it is flexible enough to change transiently the architecture of its network in order to perform the required computations. PMID:20640245

  14. Multisegment Kinematics of the Spinal Column: Soft Tissue Artifacts Assessment.

    PubMed

    Mahallati, Sara; Rouhani, Hossein; Preuss, Richard; Masani, Kei; Popovic, Milos R

    2016-07-01

    A major challenge in the assessment of intersegmental spinal column angles during trunk motion is the inherent error in recording the movement of bony anatomical landmarks caused by soft tissue artifacts (STAs). This study aims to perform an uncertainty analysis and estimate the typical errors induced by STA into the intersegmental angles of a multisegment spinal column model during trunk bending in different directions by modeling the relative displacement between skin-mounted markers and actual bony landmarks during trunk bending. First, we modeled the maximum displacement of markers relative to the bony landmarks with a multivariate Gaussian distribution. In order to estimate the distribution parameters, we measured these relative displacements on five subjects at maximum trunk bending posture. Then, in order to model the error depending on trunk bending angle, we assumed that the error grows linearly as a function of the bending angle. Second, we applied our error model to the trunk motion measurement of 11 subjects to estimate the corrected trajectories of the bony landmarks and investigate the errors induced into the intersegmental angles of a multisegment spinal column model. For this purpose, the trunk was modeled as a seven-segment rigid-body system described using 23 reflective markers placed on various bony landmarks of the spinal column. Eleven seated subjects performed trunk bending in five directions and the three-dimensional (3D) intersegmental angles during trunk bending were calculated before and after error correction. While STA minimally affected the intersegmental angles in the sagittal plane (<16%), it considerably corrupted the intersegmental angles in the coronal (error ranged from 59% to 551%) and transverse (up to 161%) planes. Therefore, we recommend using the proposed error suppression technique for STA-induced error compensation as a tool to achieve more accurate spinal column kinematics measurements. Particularly, for intersegmental

  15. Competitive displacement among insects and arachnids.

    PubMed

    Reitz, Stuart R; Trumble, John T

    2002-01-01

    Competitive displacement is the most severe outcome of interspecific competition. For the purposes of this review, we define this type of displacement as the removal of a formerly established species from a habitat as a result of direct or indirect competitive interactions with another species. We reviewed the literature for recent putative cases of competitive displacement among insects and arachnids and assessed the evidence for the role of interspecific competition in these displacements. We found evidence for mechanisms of both exploitation and interference competition operating in these cases of competitive displacement. Many of the cases that we identified involve the operation of more than one competitive mechanism, and many cases were mediated by other noncompetitive factors. Most, but not all, of these displacements occurred between closely related species. In the majority of cases, exotic species displaced native species or previously established exotic species, often in anthropogenically-altered habitats. The cases that we identified have occurred across a broad range of taxa and environments. Therefore we suggest that competitive displacement has the potential to be a widespread phenomenon, and the frequency of these displacement events may increase, given the ever-increasing degree of anthropogenic changes to the environment. A greater awareness of competitive displacement events should lead to more studies documenting the relative importance of key factors and developing hypotheses that explain observed patterns.

  16. Fracture Behaviour of Glass Columns Experimental Study of Axial Loaded Glass Columns

    NASA Astrophysics Data System (ADS)

    Jakab, A.; Nehme, K.; Nehme, S. G.

    2016-04-01

    Nowadays supporting structures can be transparent due to the development of glass strengthening procedures. The building glass as a versatile building material enables the efforts of the architects due to its transparency. This paper focuses on glass columns in the topic of load-bearing glasses and also on the design and load bearing capacity of fins and stability issues. Laboratory experiments were carried out at the BME, Department of Building Materials and Engineering Geology on the fracture behaviour of centrally compressed glass columns. More than 120 specimens where loaded until fracture. The load and deformations were measured. Based on the experimental results the critical force was determined and with force-deflection diagrams were illustrated the fracture and stability processes. Authors are going to compare the results of the laboratory experiments and theoretical calculations.

  17. Youths' Displaced Aggression against in- and Out-Group Peers: An Experimental Examination

    ERIC Educational Resources Information Center

    Reijntjes, Albert; Thomaes, Sander; Kamphuis, Jan H.; Bushman, Brad J.; Reitz, Ellen; Telch, Michael J.

    2013-01-01

    People often displace their anger and aggression against innocent targets, sometimes called scapegoats. Tragic historic events suggest that members of ethnic minority out-groups may be especially likely to be innocent targets. The current experiment examined displaced aggression of Dutch youths against Dutch in-group peers versus Moroccan…

  18. A noncontact FMCW radar sensor for displacement measurement in structural health monitoring.

    PubMed

    Li, Cunlong; Chen, Weimin; Liu, Gang; Yan, Rong; Xu, Hengyi; Qi, Yi

    2015-03-26

    This paper investigates the Frequency Modulation Continuous Wave (FMCW) radar sensor for multi-target displacement measurement in Structural Health Monitoring (SHM). The principle of three-dimensional (3-D) displacement measurement of civil infrastructures is analyzed. The requirements of high-accuracy displacement and multi-target identification for the measuring sensors are discussed. The fundamental measuring principle of FMCW radar is presented with rigorous mathematical formulas, and further the multiple-target displacement measurement is analyzed and simulated. In addition, a FMCW radar prototype is designed and fabricated based on an off-the-shelf radar frontend and data acquisition (DAQ) card, and the displacement error induced by phase asynchronism is analyzed. The conducted outdoor experiments verify the feasibility of this sensing method applied to multi-target displacement measurement, and experimental results show that three targets located at different distances can be distinguished simultaneously with millimeter level accuracy.

  19. A noncontact FMCW radar sensor for displacement measurement in structural health monitoring.

    PubMed

    Li, Cunlong; Chen, Weimin; Liu, Gang; Yan, Rong; Xu, Hengyi; Qi, Yi

    2015-01-01

    This paper investigates the Frequency Modulation Continuous Wave (FMCW) radar sensor for multi-target displacement measurement in Structural Health Monitoring (SHM). The principle of three-dimensional (3-D) displacement measurement of civil infrastructures is analyzed. The requirements of high-accuracy displacement and multi-target identification for the measuring sensors are discussed. The fundamental measuring principle of FMCW radar is presented with rigorous mathematical formulas, and further the multiple-target displacement measurement is analyzed and simulated. In addition, a FMCW radar prototype is designed and fabricated based on an off-the-shelf radar frontend and data acquisition (DAQ) card, and the displacement error induced by phase asynchronism is analyzed. The conducted outdoor experiments verify the feasibility of this sensing method applied to multi-target displacement measurement, and experimental results show that three targets located at different distances can be distinguished simultaneously with millimeter level accuracy. PMID:25822139

  20. A Noncontact FMCW Radar Sensor for Displacement Measurement in Structural Health Monitoring

    PubMed Central

    Li, Cunlong; Chen, Weimin; Liu, Gang; Yan, Rong; Xu, Hengyi; Qi, Yi

    2015-01-01

    This paper investigates the Frequency Modulation Continuous Wave (FMCW) radar sensor for multi-target displacement measurement in Structural Health Monitoring (SHM). The principle of three-dimensional (3-D) displacement measurement of civil infrastructures is analyzed. The requirements of high-accuracy displacement and multi-target identification for the measuring sensors are discussed. The fundamental measuring principle of FMCW radar is presented with rigorous mathematical formulas, and further the multiple-target displacement measurement is analyzed and simulated. In addition, a FMCW radar prototype is designed and fabricated based on an off-the-shelf radar frontend and data acquisition (DAQ) card, and the displacement error induced by phase asynchronism is analyzed. The conducted outdoor experiments verify the feasibility of this sensing method applied to multi-target displacement measurement, and experimental results show that three targets located at different distances can be distinguished simultaneously with millimeter level accuracy. PMID:25822139

  1. Fluid trapping during capillary displacement in fractures

    NASA Astrophysics Data System (ADS)

    Yang, Zhibing; Neuweiler, Insa; Méheust, Yves; Fagerlund, Fritjof; Niemi, Auli

    2016-09-01

    The spatial distribution of fluid phases and the geometry of fluid-fluid interfaces resulting from immiscible displacement in fractures cast decisive influence on a range of macroscopic flow parameters. Most importantly, these are the relative permeabilities of the fluids as well as the macroscopic irreducible saturations. They also influence parameters for component (solute) transport, as it usually occurs through one of the fluid phase only. Here, we present a numerical investigation on the critical role of aperture variation and spatial correlation on fluid trapping and the morphology of fluid phase distributions in a geological fracture. We consider drainage in the capillary dominated regime. The correlation scale, that is, the scale over which the two facing fracture walls are matched, varies among the investigated geometries between L/256 and L (self-affine fields), L being the domain/fracture length. The aperture variability is quantified by the coefficient of variation (δ), ranging among the various geometries from 0.05 to 0.25. We use an invasion percolation based model which has been shown to properly reproduce displacement patterns observed in previous experiments. We present a quantitative analysis of the size distribution of trapped fluid clusters. We show that when the in-plane curvature is considered, the amount of trapped fluid mass first increases with increasing correlation scale Lc and then decreases as Lc further increases from some intermediate scale towards the domain length scale L. The in-plane curvature contributes to smoothening the invasion front and to dampening the entrapment of fluid clusters of a certain size range that depends on the combination of random aperture standard deviation and spatial correlation.

  2. Displacement speeds in turbulent premixed flame simulations

    SciTech Connect

    Day, Marcus S.; Shepherd, Ian G.; Bell, J.; Grcar, Joseph F.; Lijewski, Michael J.

    2007-07-01

    The theory of turbulent premixed flames is based on acharacterization of the flame as a discontinuous surface propagatingthrough the fluid. The displacement speed, defined as the local speed ofthe flame front normal to itself, relative to the unburned fluid,provides one characterization of the burning velocity. In this paper, weintroduce a geometric approach to computing displacement speed anddiscuss the efficacy of the displacement speed for characterizing aturbulent flame.

  3. The formation of spikes in the displacement of miscible fluids

    NASA Technical Reports Server (NTRS)

    Rashidnia, N.; Balasubramaniam, R.; Schroer, R. T.

    2004-01-01

    We report on experiments in which a more viscous fluid displaces a less viscous one in a vertical cylindrical tube. These experiments were performed using silicone oils in a vertical pipette of small diameter. The more viscous fluid also had a slightly larger density than the less viscous fluid. In the initial configuration, the fluids were at rest, and the interface was nominally flat. A dye was added to the more viscous fluid for ease of observation of the interface between the fluids. The flow was initiated by pumping the more viscous fluid into the less viscous one. The displacement velocity was such that the Reynolds number was smaller than unity and the Peclet number for mass transfer between the fluids was large compared to unity. For upward displacement of the more viscous fluid from an initially stable configuration, an axisymmetric finger was observed under all conditions. However, a needle-shaped spike was seen to propagate from the main finger in many cases, similar to that observed by Petitjeans and Maxworthy for the displacement of a more viscous fluid by a less viscous one.

  4. Plane shock wave interaction with a cylindrical water column

    NASA Astrophysics Data System (ADS)

    Sembian, S.; Liverts, M.; Tillmark, N.; Apazidis, N.

    2016-05-01

    A complex system of waves propagating inside a water column due to the impact of plane shock wave is investigated both experimentally and numerically. Flow features, such as, focusing of expansion waves generating large negative pressure, nucleation of cavitation bubbles, and a re-circulation zone are observed and discussed qualitatively and quantitatively. Experiments are conducted on a 22 mm diametrical water column hit by shock waves with Mach numbers 1.75 and 2.4 in a newly constructed exploding wire facility. A new technique to create a properly shaped, repeatable, large diameter water column with straight walls is presented. Qualitative features of the flow are captured using the shadowgraph technique. With the aid of numerical simulations the wave motions inside the column are analyzed; the spatial location of the expansion wave focusing point and the corresponding negative peak pressures is estimated.

  5. Displacement based multilevel structural optimization

    NASA Technical Reports Server (NTRS)

    Striz, Alfred G.

    1995-01-01

    Multidisciplinary design optimization (MDO) is expected to play a major role in the competitive transportation industries of tomorrow, i.e., in the design of aircraft and spacecraft, of high speed trains, boats, and automobiles. All of these vehicles require maximum performance at minimum weight to keep fuel consumption low and conserve resources. Here, MDO can deliver mathematically based design tools to create systems with optimum performance subject to the constraints of disciplines such as structures, aerodynamics, controls, etc. Although some applications of MDO are beginning to surface, the key to a widespread use of this technology lies in the improvement of its efficiency. This aspect is investigated here for the MDO subset of structural optimization, i.e., for the weight minimization of a given structure under size, strength, and displacement constraints. Specifically, finite element based multilevel optimization of structures (here, statically indeterminate trusses and beams for proof of concept) is performed. In the system level optimization, the design variables are the coefficients of assumed displacement functions, and the load unbalance resulting from the solution of the stiffness equations is minimized. Constraints are placed on the deflection amplitudes and the weight of the structure. In the subsystems level optimizations, the weight of each element is minimized under the action of stress constraints, with the cross sectional dimensions as design variables. This approach is expected to prove very efficient, especially for complex structures, since the design task is broken down into a large number of small and efficiently handled subtasks, each with only a small number of variables. This partitioning will also allow for the use of parallel computing, first, by sending the system and subsystems level computations to two different processors, ultimately, by performing all subsystems level optimizations in a massively parallel manner on separate

  6. FRACTIONATING COLUMN PRODUCT COLLECTOR CONTROL

    DOEpatents

    Paxson, G.D. Jr.

    1964-03-10

    Means for detecting minute fluid products from a chemical separation column and for advancing a collector tube rack in order to automatically separate and collect successive fractionated products are described. A charge is imposed on the forming drops at the column orifice to create an electric field as the drop falls in the vicinity of a sensing plate. The field is detected by an electrometer tube coupled to the plate causing an output signal to actuate rotation of a collector turntable rack, thereby positioning new collectors under the orifice. The invention provides reliable automatic collection independent of drop size, rate of fall, or chemical composition. (AEC)

  7. Polybenzoxazole via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1993-01-01

    Polybenzoxazoles (PBO) are heterocyclic macromolecules which were first synthesized in a two-step process by the initial formation of aromatic diacid chlorides with bis(o-aminophenol)s through solution condensation of aromatic diacid chlorides with bis(o-aminophenol)s followed by thermal cyclodehydration. Since then several methods were utilized in their synthesis. The most common synthetic method for PBO involves a polycondensation of bis(o-aminophenol)s with aromatic diacid diphenyl esters. Another preparative route involves the solution polycondensation of the hydrochloride salts of bis(o-amino phenol)s with aromatic diacids in polyphosphoric acid. Another synthetic method involves the initial formation of poly(o-hydroxy amide)s from silylated bis(o-aminophenol)s with aromatic diacid chlorides followed by thermal cyclodehydration to PBO. A recent preparative route involves the reaction of aromatic bisphenols with bis(fluorophenyl) benzoxazoles by the displacement reaction to form PBO. The novelty of the present invention is that high molecular weight PBO of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  8. Isolation of Three Components from Spearmint Oil: An Exercise in Column and Thin-Layer Chromatography

    ERIC Educational Resources Information Center

    Davies, Don R.; Johnson, Todd M.

    2007-01-01

    A simple experiment for undergraduate organic chemistry students to separate a colorless mixture using column chromatography and then monitor the outcome of the separation using thin-layer chromatography (TLC) and infrared spectroscopy(IR) is described. The experiment teaches students the principle and techniques of column and thin-layer…

  9. Measuring Relative-Story Displacement and Local Inclination Angle Using Multiple Position-Sensitive Detectors

    PubMed Central

    Matsuya, Iwao; Katamura, Ryuta; Sato, Maya; Iba, Miroku; Kondo, Hideaki; Kanekawa, Kiyoshi; Takahashi, Motoichi; Hatada, Tomohiko; Nitta, Yoshihiro; Tanii, Takashi; Shoji, Shuichi; Nishitani, Akira; Ohdomari, Iwao

    2010-01-01

    We propose a novel sensor system for monitoring the structural health of a building. The system optically measures the relative-story displacement during earthquakes for detecting any deformations of building elements. The sensor unit is composed of three position sensitive detectors (PSDs) and lenses capable of measuring the relative-story displacement precisely, even if the PSD unit was inclined in response to the seismic vibration. For verification, laboratory tests were carried out using an Xθ-stage and a shaking table. The static experiment verified that the sensor could measure the local inclination angle as well as the lateral displacement. The dynamic experiment revealed that the accuracy of the sensor was 150 μm in the relative-displacement measurement and 100 μrad in the inclination angle measurement. These results indicate that the proposed sensor system has sufficient accuracy for the measurement of relative-story displacement in response to the seismic vibration. PMID:22163434

  10. Effects of Fault Displacement on Emplacement Drifts

    SciTech Connect

    F. Duan

    2000-04-25

    The purpose of this analysis is to evaluate potential effects of fault displacement on emplacement drifts, including drip shields and waste packages emplaced in emplacement drifts. The output from this analysis not only provides data for the evaluation of long-term drift stability but also supports the Engineered Barrier System (EBS) process model report (PMR) and Disruptive Events Report currently under development. The primary scope of this analysis includes (1) examining fault displacement effects in terms of induced stresses and displacements in the rock mass surrounding an emplacement drift and (2 ) predicting fault displacement effects on the drip shield and waste package. The magnitude of the fault displacement analyzed in this analysis bounds the mean fault displacement corresponding to an annual frequency of exceedance of 10{sup -5} adopted for the preclosure period of the repository and also supports the postclosure performance assessment. This analysis is performed following the development plan prepared for analyzing effects of fault displacement on emplacement drifts (CRWMS M&O 2000). The analysis will begin with the identification and preparation of requirements, criteria, and inputs. A literature survey on accommodating fault displacements encountered in underground structures such as buried oil and gas pipelines will be conducted. For a given fault displacement, the least favorable scenario in term of the spatial relation of a fault to an emplacement drift is chosen, and the analysis is then performed analytically. Based on the analysis results, conclusions are made regarding the effects and consequences of fault displacement on emplacement drifts. Specifically, the analysis will discuss loads which can be induced by fault displacement on emplacement drifts, drip shield and/or waste packages during the time period of postclosure.

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

    NASA Astrophysics Data System (ADS)

    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

  12. Displaced Homemakers: Vo-Tech Workshop Guide.

    ERIC Educational Resources Information Center

    Peltier, Wanda Jo

    Written for displaced homemaker programs in vocational-technical schools, this curriculum contains material designed so that instructors can prepare student manuals appropriate to almost any educational support situation for displaced homemakers. An overview provides information on special needs groups, curriculum use, and resources and sample…

  13. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Engine displacement. 205.153 Section 205.153 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a)...

  14. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Engine displacement. 205.153 Section 205.153 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a)...

  15. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Engine displacement. 205.153 Section 205.153 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a)...

  16. Video Games, Adolescents, and the Displacement Effect

    ERIC Educational Resources Information Center

    Fisher, Carla Christine

    2012-01-01

    The displacement effect (the idea that time spent in one activity displaces time spent in other activities) was examined within the lens of adolescents' video game use and their time spent reading, doing homework, in physically active sports and activities, in creative play, and with parents and friends. Data were drawn from the Panel Study…

  17. 20 CFR 211.8 - Displacement allowance.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Displacement allowance. 211.8 Section 211.8 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT CREDITABLE RAILROAD COMPENSATION § 211.8 Displacement allowance. An allowance paid to an employee because he has...

  18. 20 CFR 211.8 - Displacement allowance.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Displacement allowance. 211.8 Section 211.8 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT CREDITABLE RAILROAD COMPENSATION § 211.8 Displacement allowance. An allowance paid to an employee because he has...

  19. 20 CFR 211.8 - Displacement allowance.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Displacement allowance. 211.8 Section 211.8 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT CREDITABLE RAILROAD COMPENSATION § 211.8 Displacement allowance. An allowance paid to an employee because he has...

  20. 20 CFR 211.8 - Displacement allowance.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Displacement allowance. 211.8 Section 211.8 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT CREDITABLE RAILROAD COMPENSATION § 211.8 Displacement allowance. An allowance paid to an employee because he has...

  1. 20 CFR 211.8 - Displacement allowance.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Displacement allowance. 211.8 Section 211.8 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT CREDITABLE RAILROAD COMPENSATION § 211.8 Displacement allowance. An allowance paid to an employee because he has...

  2. Imaging fluid saturation development in long-core flood displacements

    SciTech Connect

    Grave, A.; Kolitvelt, K.; Lien, J.R.; Skauge, A. )

    1990-12-01

    Fluid saturation development in long-core flood experiments is investigated. Information on 1D fluid saturation distributions is obtained by labeling the fluid phases with nuclear tracers and detecting radiation with a movable detector. Various flood experiments were done on 2.5-ft (76-cm)-long sandstone cores. In miscible displacements where radioactive brine is displacing inactive brine, dispersion and ion adsorption are evaluated. Imaging saturation profiles during drainages and waterfloods gives information on saturation front velocity and time development of local saturation variations. Experimental results are compared with numerical results from a 1D front-tracking black-oil simulator that incorporated inhomogeneities and capillary effects. Surfactant floods were investigated to test the applicability for EOR studies.

  3. Using a 2D displacement sensor to derive 3D displacement information

    NASA Technical Reports Server (NTRS)

    Soares, Schubert F. (Inventor)

    2002-01-01

    A 2D displacement sensor is used to measure displacement in three dimensions. For example, the sensor can be used in conjunction with a pulse-modulated or frequency-modulated laser beam to measure displacement caused by deformation of an antenna on which the sensor is mounted.

  4. Simulations of threshold displacement in beryllium

    NASA Astrophysics Data System (ADS)

    Jackson, Matthew L.; Fossati, Paul C. M.; Grimes, Robin W.

    2016-07-01

    Atomic scale molecular dynamics simulations of radiation damage have been performed on beryllium. Direct threshold displacement simulations along a geodesic projection of directions were used to investigate the directional dependence with a high spatial resolution. It was found that the directionally averaged probability of displacement increases from 0 at 35 eV, with the energy at which there is a 50% chance of a displacement occurring is 70 eV and asymptotically approaching 1 for higher energies. This is, however, strongly directionally dependent with a 50% probability of displacement varying from 35 to 120 eV, with low energy directions corresponding to the nearest neighbour directions. A new kinetic energy dependent expression for the average maximum displacement of an atom as a function of energy is derived which closely matches the simulated data.

  5. Rotational Displacement Skills in Rhesus Macaques (Macaca mulatta)

    PubMed Central

    Hughes, Kelly D.; Santos, Laurie R.

    2016-01-01

    Rotational displacement tasks, in which participants must track an object at a hiding location within an array while the array rotates, exhibit a puzzling developmental pattern in humans. Human children take an unusually long time to master this task and tend to solve rotational problems through the use of nongeometric features or landmarks as opposed to other kinds of spatial cues. We investigated whether these developmental characteristics are unique to humans by testing rotational displacement skills in a monkey species, the rhesus macaque (Macaca mulatta), using a looking-time method. Monkeys first saw food hidden in two differently colored boxes within an array. The array was then rotated 180° and the boxes reopened to reveal the food in an expected or unexpected location. Our first two experiments explored the developmental time-course of performance on this rotational displacement task. We found that adult macaques looked longer at the unexpected event, but such performance was not mirrored in younger-aged macaques. In a third study, we systematically varied featural information and visible access to the array to investigate which strategies adult macaques used in solving rotational displacements. Our results show that adult macaques need both sets of information to solve the task. Taken together, these results suggest both similarities and differences in mechanisms by which human and nonhuman primates develop this spatial skill. PMID:22866770

  6. Mechanisms of displacement discrimination with and without perceived movement.

    PubMed

    Palmer, J

    1986-11-01

    A nearby visual reference point improves displacement discrimination. This effect occurs regardless of the delay between successive displays. The delay can be varied from short delays (50 ms), where observers report perceived movement, to long delays (2,000 ms), where observers report no movement. The similarity of reference effects for such different delay conditions was investigated by testing the independence of reference and delay effects. The critical independence property is whether the spatial variables (displacement and separation from the visual reference) combine independently of the temporal variable (delay). This kind of independence did not hold for displacement discrimination at delays of 50 ms and 2,000 ms. A further experiment tested for the independence property at delays of 500 ms and 4,000 ms, where observers reported no perceived movement. For these longer delays, the property was satisfied. These results are discussed using the general concept of a psychophysical mechanism. Such a mechanism combines the effects of several stimulus variables into a single mediating representation. By this analysis, at least two mechanisms must mediate the reference effect on displacement discrimination, one for delays of 200 ms and less and another for delays of 500 ms and more.

  7. Policies to Reduce High-Tenured Displaced Workers' Earnings Losses through Retraining. Discussion Paper 2011-11

    ERIC Educational Resources Information Center

    Jacobson, Louis S.; LaLonde, Robert J.; Sullivan, Daniel G.

    2011-01-01

    High-tenured displaced workers often experience significant earnings losses that persist for the rest of their working lives. A well-targeted training initiative has the potential to substantially reduce permanent earnings losses for those displaced workers who have the academic preparation, work experience, and interest to complete high-return…

  8. Phosphate adsorption on granular palygorskite: batch and column studies.

    PubMed

    Fangqun, Gan; Jianmin, Zhou; Huoyan, Wang; Changwen, Du; Wenzhao, Zhang; Xiaoqin, Chen

    2011-02-01

    A method to prepare granular palygorskite (GPA) was put forward in this research, and its potential use to remove phosphate species from aqueous solution was assessed. Batch experiments were performed to study the adsorption equilibrium and influence of contact time and pH on the adsorption and desorption of phosphate onto GPA in water. The maximum phosphate adsorption capacity of GPA was 13.1 mg/g. Kinetic data revealed that more than 90% of phosphate was adsorbed onto GPA within 2 hours. Phosphate adsorption capacity was 0.10 mg/g in column experiments, and co-existing anions could decrease phosphate removal. The saturated column was regenerated by 0.2 mol/L sodium hydroxide, and the GPA could be reused in phosphate removal. The data obtained from both batch and column studies indicated that GPA could be used effectively to remove phosphate from water.

  9. Intrinsic Mean Square Displacement in Proteins

    NASA Astrophysics Data System (ADS)

    Vural, Derya; Glyde, Henry R.

    2012-02-01

    The dynamics of biological molecules is investigated in neutron scattering experiments, in molecular dynamics simulations, and using analytical theory. Specifically, the mean square displacement (MSD), exp, of hydrogen in proteins is determined from measurements of the incoherent elastic neutron scattering intensity (ENSI). The MSD, exp, is usually obtained from the dependence of the ENSI on the scattering wave vector Q. The MSD increases with increasing temperature reaching large values at room temperature. Large MSD is often associated with and used as an indicator of protein function. The observed MSD, however, depends on the energy resolution of the neutron spectrometer employed. We present a method, a first attempt, to extract the intrinsic MSD of hydrogen in protein from measurements, one that is independent of the instrument resolution. The method consists of a model of the ENSI that contains (1) the intrinsic MSD, (2) the instrument resolution width and (3) a parameter describing the motional processes that contribute to the MSD. Several examples of intrinsic MSDs in proteins obtained from fitting to data in the existing literature will be presented.

  10. Preparation and Characterization of a Polymeric Monolithic Column for Use in High-Performance Liquid Chromatography (HPLC)

    ERIC Educational Resources Information Center

    Bindis, Michael P.; Bretz, Stacey Lowery; Danielson, Neil D.

    2011-01-01

    The high-performance liquid chromatography (HPLC) experiment, most often done in the undergraduate analytical instrumentation laboratory course, generally illustrates reversed-phase chromatography using a commercial C[subscript]18 silica column. To avoid the expense of periodic column replacement and introduce a choice of columns with different…

  11. Beam Studies with Electron Columns

    SciTech Connect

    Shiltsev, V.; Valishev, A.; Kuznetsov, G.; Kamerdzhiev, V.; 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.

  12. Cyclic performance and simplified pushover analyses of precast segmental concrete bridge columns with circular section

    NASA Astrophysics Data System (ADS)

    Bu, Zhanyu; Guo, Jian; Zheng, Rongyue; Song, Jianwei; Lee, George C.

    2016-06-01

    In recent years, precast segmental concrete bridge columns became prevalent because of the benefits of accelerated construction, low environmental impact, high quality and low life cycle costs. The lack of a detailed configuration and appropriate design procedure to ensure a comparable performance with monolithic construction has impeded this structural system from being widely used in areas of high seismicity. In this study, precast segmental bridge column cyclic loading tests were conducted to investigate the performance of unbonded post-tensioned segmental bridge columns. One monolithic and two precast segmental columns were tested. The precast segmental column exhibited minor damage and small residual displacement after the maximum 7% cyclic drift; energy dissipation (ED) can be enhanced byadding ED bars. The experimental results were modeled by a simplified pushover method (SPOM), as well as a fiber model (FIBM) finite element method. Forty-five cases of columns with different aspect ratios, axial load ratios and ED bar ratios were analyzed with the SPOM and FIBM, respectively. Using these parametric results, a simplified design method was suggested by regressive analysis. Satisfactory correlation was found between the experimental results and the simplified design method for precast segmental columns with different design parameters.

  13. Carbon dioxide column abundances at the Wisconsin Tall Tower site

    NASA Astrophysics Data System (ADS)

    Washenfelder, R. A.; Toon, G. C.; Blavier, J.-F.; Yang, Z.; Allen, N. T.; Wennberg, P. O.; Vay, S. A.; Matross, D. M.; Daube, B. C.

    2006-11-01

    We have developed an automated observatory for measuring atmospheric column abundances of CO2 and O2 using near-infrared spectra of the Sun obtained with a high spectral resolution Fourier Transform Spectrometer (FTS). This is the first dedicated laboratory in a new network of ground-based observatories named the Total Carbon Column Observing Network. This network will be used for carbon cycle studies and validation of spaceborne column measurements of greenhouse gases. The observatory was assembled in Pasadena, California, and then permanently deployed to northern Wisconsin during May 2004. It is located in the heavily forested Chequamegon National Forest at the WLEF Tall Tower site, 12 km east of Park Falls, Wisconsin. Under clear sky conditions, ˜0.1% measurement precision is demonstrated for the retrieved column CO2 abundances. During the Intercontinental Chemical Transport Experiment-North America and CO2 Boundary Layer Regional Airborne Experiment campaigns in summer 2004, the DC-8 and King Air aircraft recorded eight in situ CO2 profiles over the WLEF site. Comparison of the integrated aircraft profiles and CO2 column abundances shows a small bias (˜2%) but an excellent correlation.

  14. Variable displacement alpha-type Stirling engine

    NASA Astrophysics Data System (ADS)

    Homutescu, V. M.; Bălănescu, D. T.; Panaite, C. E.; Atanasiu, M. V.

    2016-08-01

    The basic design and construction of an alpha-type Stirling engine with on load variable displacement is presented. The variable displacement is obtained through a planar quadrilateral linkage with one on load movable ground link. The physico-mathematical model used for analyzing the variable displacement alpha-type Stirling engine behavior is an isothermal model that takes into account the real movement of the pistons. Performances and power adjustment capabilities of such alpha-type Stirling engine are calculated and analyzed. An exemplification through the use of the numerical simulation was performed in this regard.

  15. Repetitive Regeneration of Media #1 in a Dynamic Column Extraction using Brine #1

    SciTech Connect

    Gary Garland

    2015-10-14

    This data is from a regeneration study from a dynamic column extraction experiment where we ran a solution of REE's through a column of media #1 then stripped the REE's off the media using 2M HNO3 solution. We then re-equilibrated the media and repeated the process of running a REE solution through the column and stripping the REE's off the media and comparing the two runs.

  16. PDT - PARTICLE DISPLACEMENT TRACKING SOFTWARE

    NASA Technical Reports Server (NTRS)

    Wernet, M. P.

    1994-01-01

    Particle Imaging Velocimetry (PIV) is a quantitative velocity measurement technique for measuring instantaneous planar cross sections of a flow field. The technique offers very high precision (1%) directionally resolved velocity vector estimates, but its use has been limited by high equipment costs and complexity of operation. Particle Displacement Tracking (PDT) is an all-electronic PIV data acquisition and reduction procedure which is simple, fast, and easily implemented. The procedure uses a low power, continuous wave laser and a Charged Coupled Device (CCD) camera to electronically record the particle images. A frame grabber board in a PC is used for data acquisition and reduction processing. PDT eliminates the need for photographic processing, system costs are moderately low, and reduced data are available within seconds of acquisition. The technique results in velocity estimate accuracies on the order of 5%. The software is fully menu-driven from the acquisition to the reduction and analysis of the data. Options are available to acquire a single image or 5- or 25-field series of images separated in time by multiples of 1/60 second. The user may process each image, specifying its boundaries to remove unwanted glare from the periphery and adjusting its background level to clearly resolve the particle images. Data reduction routines determine the particle image centroids and create time history files. PDT then identifies the velocity vectors which describe the particle movement in the flow field. Graphical data analysis routines are included which allow the user to graph the time history files and display the velocity vector maps, interpolated velocity vector grids, iso-velocity vector contours, and flow streamlines. The PDT data processing software is written in FORTRAN 77 and the data acquisition routine is written in C-Language for 80386-based IBM PC compatibles running MS-DOS v3.0 or higher. Machine requirements include 4 MB RAM (3 MB Extended), a single or

  17. Displacement of oil by carbon dioxide. Final report

    SciTech Connect

    Orr, Jr., F. M.; Taber, J. J.

    1981-05-01

    Results of a comprehensive research program on factors influencing CO/sub 2/ flooding are reported. Equipment constructed for static equilibrium measurements of phase volumes, compositions, densities and viscosities is described. Design of an apparatus used for a variety of displacement tests is also reported. Apparatus and experimental procedures are described for a new experiment in which equilibrium phase compositions can be measured rapidly and continuously. Results of displacements of crude oil from slim tubes, cores and mixing cells are presented and interpreted in terms of detailed measurements of the phase behavior and fluid properties of the CO/sub 2/-crude oil mixtures. The complex phase behavior of low temperature CO/sub 2/-crude oil mixtures is described and compared with similar behavior for CO/sub 2/-alkane mixtures. A simple correlation is offered for the ranges of reservoir temperature and pressure at which liquid-liquid and liquid-liquid-vapor phase behavior should be expected to occur. Direct evidence is presented of the efficiency with which a CO/sub 2/-rich liquid phase can extract hydrocarbons from a crude oil. A simple one-dimensional process simulator for CO/sub 2/ flooding applications is described. Simulation results are compared with experimental data from slim tube displacements. Good agreement is reported between calculated and experimental results as long as the volume change of CO/sub 2/ on mixing with the oil is not too great.Sensitivity of calculated results to phase behavior and fluid properties is discussed. Comparison of displacement results, phase behavior measurements, and model calculations provides strong evidence that the high displacement efficiency which can be obtained when pressure is high enough and viscous fingering is controlled is the result of efficient extraction of a broad range of hydrocarbons by a dense CO/sub 2/-rich phase which is a liquid if the temperature is below about 50/sup 0/C (130/sup 0/F).

  18. Continuous and Batch Distillation in an Oldershaw Tray Column

    ERIC Educational Resources Information Center

    Silva, Carlos M.; Vaz, Raquel V.; Santiago, Ana S.; Lito, Patricia F.

    2011-01-01

    The importance of distillation in the separation field prompts the inclusion of distillation experiments in the chemical engineering curricula. This work describes the performance of an Oldershaw column in the rectification of a cyclohexane/n-heptane mixture. Total reflux distillation, continuous rectification under partial reflux, and batch…

  19. Herbicide Leaching Column for a Weed Science Teaching Laboratory.

    ERIC Educational Resources Information Center

    Ahrens, W. H.

    1986-01-01

    Presents an experiment which enables weed science students to observe first-hand the process of herbicide leaching in soils. Features of this technique which demonstrate the movement of herbicide within a column of soil are outlined. Diagrams are provided of the apparatus employed in the exercise. (ML)

  20. Comparison of neptunium sorption results using batch and column techniques

    SciTech Connect

    Triay, I.R.; Furlano, A.C.; Weaver, S.C.; Chipera, S.J.; Bish, D.L.

    1996-08-01

    We used crushed-rock columns to study the sorption retardation of neptunium by zeolitic, devitrified, and vitric tuffs typical of those at the site of the potential high-level nuclear waste repository at Yucca Mountain, Nevada. We used two sodium bicarbonate waters (groundwater from Well J-13 at the site and water prepared to simulate groundwater from Well UE-25p No. 1) under oxidizing conditions. It was found that values of the sorption distribution coefficient, Kd, obtained from these column experiments under flowing conditions, regardless of the water or the water velocity used, agreed well with those obtained earlier from batch sorption experiments under static conditions. The batch sorption distribution coefficient can be used to predict the arrival time for neptunium eluted through the columns. On the other hand, the elution curves showed dispersivity, which implies that neptunium sorption in these tuffs may be nonlinear, irreversible, or noninstantaneous. As a result, use of a batch sorption distribution coefficient to calculate neptunium transport through Yucca Mountain tuffs would yield conservative values for neptunium release from the site. We also noted that neptunium (present as the anionic neptunyl carbonate complex) never eluted prior to tritiated water, which implies that charge exclusion does not appear to exclude neptunium from the tuff pores. The column experiments corroborated the trends observed in batch sorption experiments: neptunium sorption onto devitrified and vitric tuffs is minimal and sorption onto zeolitic tuffs decreases as the amount of sodium and bicarbonate/carbonate in the water increases.

  1. Bridge Displacement Monitoring Method Based on Laser Projection-Sensing Technology

    PubMed Central

    Zhao, Xuefeng; Liu, Hao; Yu, Yan; Xu, Xiaodong; Hu, Weitong; Li, Mingchu; Ou, Jingping

    2015-01-01

    Bridge displacement is the most basic evaluation index of the health status of a bridge structure. The existing measurement methods for bridge displacement basically fail to realize long-term and real-time dynamic monitoring of bridge structures, because of the low degree of automation and the insufficient precision, causing bottlenecks and restriction. To solve this problem, we proposed a bridge displacement monitoring system based on laser projection-sensing technology. First, the laser spot recognition method was studied. Second, the software for the displacement monitoring system was developed. Finally, a series of experiments using this system were conducted, and the results show that such a system has high measurement accuracy and speed. We aim to develop a low-cost, high-accuracy and long-term monitoring method for bridge displacement based on these preliminary efforts. PMID:25871716

  2. Experimental determination of force and displacement of a car suspension

    NASA Astrophysics Data System (ADS)

    Janković, Aleksandra; Đukić, Rade

    2011-09-01

    In this paper, a dynamical laboratory testing of experimental car body connection with real elastic suspension system (ESS) is described. During the experiment a horizontal force in longitudinal direction was applied, in order to simulate an acceleration and deceleration regime of a vehicle. The experiment was carried out on the example of two car bodies, with identical geometric behavior but implemented engine compartment was made of different materials: in one case it was made of steel and in another one of Al-alloys. The obtained displacement results were compared.

  3. Temperature programmable microfabricated gas chromatography column

    DOEpatents

    Manginell, Ronald P.; Frye-Mason, Gregory C.

    2003-12-23

    A temperature programmable microfabricated gas chromatography column enables more efficient chemical separation of chemical analytes in a gas mixture by the integration of a resistive heating element and temperature sensing on the microfabricated column. Additionally, means are provided to thermally isolate the heated column from their surroundings. The small heat capacity and thermal isolation of the microfabricated column improves the thermal time response and power consumption, both important factors for portable microanalytical systems.

  4. A flexible sensor measuring displacement and bending

    NASA Astrophysics Data System (ADS)

    Nishijima, Takashi; Yamamoto, Akio; Higuchi, Toshiro

    2009-04-01

    This paper proposes a new sensor that is capable of measuring both linear displacement and bending. The sensor is designed to be used with an electrostatic film motor that features mechanical flexibility, but can also be used as an independent sensor. The sensor employs three-phase electrodes both in sliding and stationary parts and estimates displacement and bending from the change of the capacitance between the electrodes. The paper describes an equivalent capacitance-network model for the sensor. Based on the model, sensing principles for both displacement and bending are presented and analyzed. The analyses are experimentally verified using a prototype sensor. The experimental results show that the prototype sensor could measure both displacement and bending with little interference between them.

  5. Giant adrenal cyst displacing the right kidney.

    PubMed

    Chodisetti, Subbarao; Boddepalli, Yogesh; Kota, Malakondareddy

    2016-01-01

    Adrenal cysts are rare and should be considered in the differential diagnosis of retroperitoneal cysts. We present a case of a huge adrenal cyst displacing the right kidney anteriorly toward the left side in a young female.

  6. 29 CFR 1926.755 - Column anchorage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) General requirements for erection stability. (1) All columns shall be anchored by a minimum of 4 anchor rods (anchor bolts). (2) Each column anchor rod (anchor bolt) assembly, including the column-to-base... of anchor rods (anchor bolts). (1) Anchor rods (anchor bolts) shall not be repaired, replaced...

  7. 29 CFR 1926.755 - Column anchorage.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Column anchorage. 1926.755 Section 1926.755 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Steel Erection § 1926.755 Column anchorage. (a) General requirements for erection stability. (1) All columns shall be anchored by a minimum of 4...

  8. Packed column supercritical fluid chromatography using deactivated stationary phases

    SciTech Connect

    Ashraf-Khorassani, M.; Taylor, L.T.; Henry, R.A.

    1988-08-01

    A new cross-linked cyanopropyl bonded phase silica (Delta-bond) has been studied as a stationary phase for packed column supercritical fluid chromatography of basic nitrogen-containing compounds. The bonded phase impedes access to uncapped silanol sites, thereby giving rise to better peak shapes and more rapid elution without the necessity of a polar modifier in the mobile phase. Experiments both at elevated temperature and in the presence of a methanol modifier revealed that there is no short- or long-term deleterious effect on the column as opposed to the conventional cyanopropyl phase.

  9. Influence of groundwater level to slope displacement by geodetic method

    NASA Astrophysics Data System (ADS)

    Sadarviana, Vera; Abidin, Hasanuddin Z.; Santoso, Djoko; Kahar, Joenil; Achmad R., T.

    2016-05-01

    In the rainy season, Indonesia often experience landslide disasters. Rainwater flows on the surface of the ground and partially into the ground, and changing the groundwater level (GWL) which can cause pressure on surrounding material. Water becomes the main factor that triggered landslides because water causes pressure force on the slopes that are prone to move. With the geometric approach, slope material displacement vectors can be known, including the origin of the material pressure using dynamic mathematical model that considers GWL. The data was used 5 campaigns of GPS observations. The results are obtained the correlation coefficients between coefficient changes in groundwater levels to the vector position as a representative of correlation between the physical and geometric parameters. There is relatively strong because of the value of the average correlation coefficient is 0.91997. Further, curves between changes in groundwater levels and the displacement position shows that the greater the groundwater levels, the greater the material position shift occurs.

  10. Analysis of displacement damage effects on MOS capacitors

    NASA Astrophysics Data System (ADS)

    Fernández-Martínez, P.; Palomo, F. R.; Hidalgo, S.; Fleta, C.; Campabadal, F.; Flores, D.

    2013-12-01

    Displacement damage effect on MOS capacitors is analyzed in this work with the aid of TCAD simulations. A noticeable capacitance reduction in the accumulation mode is observed in the High Frequency C-V characteristic curve after a 24 GeV proton irradiation. This effect is clearly distinguishable from ionizing damage effects, otherwise negligible under the specific conditions of the experiment. The capacitance reduction is identified with the increase of the substrate resistivity, due to the modification of its effective doping concentration. Supported on a well-established traps model, the expected displacement damage defects are simulated as a function of the fluence, allowing the identification of donor trap levels as the responsible of the phenomenon for p-type substrate MOS capacitors.

  11. Wettability Control on Fluid-Fluid Displacements in Patterned Microfluidics

    NASA Astrophysics Data System (ADS)

    Zhao, B.; Trojer, M.; Cueto-Felgueroso, L.; Juanes, R.

    2014-12-01

    Two-phase flow in porous media is important in many natural and industrial processes like geologic CO2 sequestration, enhanced oil recovery, and water infiltration in soil. While it is well known that the wetting properties of porous media can vary drastically depending on the type of media and the pore fluids, the effect of wettability on fluid displacement continues to challenge our microscopic and macroscopic descriptions. Here we study this problem experimentally, starting with the classic experiment of two-phase flow in a capillary tube. We image the shape of the meniscus and measure the associated capillary pressure for a wide range of capillary numbers. We confirm that wettability exerts a fundamental control on meniscus deformation, and synthesize new observations on the dependence of the dynamic capillary pressure on wetting properties (contact angle) and flow conditions (viscosity contrast and capillary number). We compare our experiments to a macroscopic phase-field model of two-phase flow. We use the insights gained from the capillary tube experiments to explore the viscous fingering instability in the Hele-Shaw geometry in the partial-wetting regime. A key difference between a Hele-Shaw cell and a porous medium is the existence of micro-structures (i.e. pores and pore throats). To investigate how these micro-structrues impact fluid-fluid displacement, we conduct experiments on a planar microfluidic device patterned with vertical posts. We track the evolution of the fluid-fluid interface and elucidate the impact of wetting on the cooperative nature of fluid displacement during pore invasion events. We use the insights gained from the capillary tube and patterned microfluidics experiments to elucidate the effect of wetting properties on viscous fingering and capillary fingering in a Hele-Shaw cell filled with glass beads, where we observe a contact-angle-dependent stabilizing behavior for the emerging flow instabilities, as the system transitions from

  12. Selenium and trace element mobility affected by periodic displacement of stratification in the Great Salt Lake, Utah

    USGS Publications Warehouse

    Beisner, K.; Naftz, D.L.; Johnson, W.P.; Diaz, X.

    2009-01-01

    The Great Salt Lake (GSL) is a unique ecosystem in which trace element activity cannot be characterized by standard geochemical parameters due to the high salinity. Movement of selenium and other trace elements present in the lake bed sediments of GSL may occur due to periodic stratification displacement events or lake bed exposure. The water column of GSL is complicated by the presence of a chemocline persistent over annual to decadal time scales. The water below the chemocline is referred to as the deep brine layer (DBL), has a high salinity (16.5 to 22.9%) and is anoxic. The upper brine layer (UBL) resides above the chemocline, has lower salinity (12.6 to 14.7%) and is oxic. Displacement of the DBL may involve trace element movement within the water column due to changes in redox potential. Evidence of stratification displacement in the water column has been observed at two fixed stations on the lake by monitoring vertical water temperature profiles with horizontal and vertical velocity profiles. Stratification displacement events occur over periods of 12 to 24 h and are associated with strong wind events that can produce seiches within the water column. In addition to displacement events, the DBL shrinks and expands in response to changes in the lake surface area over a period of months. Laboratory tests simulating the observed sediment re-suspension were conducted over daily, weekly and monthly time scales to understand the effect of placing anoxic bottom sediments in contact with oxic water, and the associated effect of trace element desorption and (or) dissolution. Results from the laboratory simulations indicate that a small percentage (1%) of selenium associated with anoxic bottom sediments is periodically solubilized into the UBL where it potentially can be incorporated into the biota utilizing the oxic part of GSL.

  13. Anaerobic biodegradation of TCE in laboratory columns of fractured saprolite.

    PubMed

    Lenczewski, Melissa E; McKay, Larry D; Layton, Alice

    2004-01-01

    An experiment was conducted to determine if biodegradation of trichloroethylene (TCE) can occur in previously uncontaminated ground water in saturated fractured saprolite (highly weathered material derived from sedimentary rocks). Two undisturbed columns (0.23 m diameter by 0.25 m long) of fractured saprolite were collected from approximately 2 m depth at an uncontaminated site on the Oak Ridge Reservation, Oak Ridge, Tennessee. Natural, uncontaminated ground water from the site, which was degassed and spiked with dissolved phase TCE, was continuously pumped through one column containing the natural microbial communities (the biotic column). In a second column, the microorganisms were inhibited and the dissolved phase TCE was added under aerobic conditions (dissolved oxygen conditions > 2 ppm). In effluent from the biotic column, reducing conditions rapidly developed and evidence of anaerobic biodegradation of TCE, by the production of cDCE, first appeared approximately 31 days after addition of TCE. Reductive dechlorination of TCE occurred after iron-reducing conditions were established and about the same time that sulfate reduction began. There was no evidence of methanogenesis. Analyses using polymerase chain reaction with specific primers sets detected the bacteria Geothrix, Geobacter, and Desulfococcus-Desulfonema-Desulfosarcina in the effluent of the biotic column, but no methanogens. The presence of these bacteria is consistent with iron- and sulfate-reducing conditions. In the inhibited column, there were no indicators of TCE degradation. Natural organic matter that occurs in the saprolite and ground water at the site is the most likely primary electron donor for supporting reductive dechlorination of TCE. The relatively rapid appearance of indicators of TCE dechlorination suggests that these processes may occur even in settings where low oxygen conditions occur seasonally due to changes in the water table.

  14. Leaching Behavior Of Mineral Processing Waste: Comparison Of Batch And Column Investigations

    EPA Science Inventory

    In this study, a comparison of laboratory batch and column experiments on metal release profile from a mineral processing waste (MPW) is presented. Batch (equilibrium) and column (dynamic) leaching tests were conducted on ground MPW at different liquid–solid ratios (LS) to determ...

  15. A straightforward methodology for designing continuous monoclonal antibody capture multi-column chromatography processes.

    PubMed

    Gjoka, Xhorxhi; Rogler, Karl; Martino, Richard Alexander; Gantier, Rene; Schofield, Mark

    2015-10-16

    A simple process development strategy for continuous capture multi-column chromatography (MCC) is described. The approach involves a few single column breakthrough experiments, based on several simplifying observations that enable users to rapidly convert batch processes into well-designed multi-column processes. The method was validated using a BioSMB(®) (Pall Life Sciences) lab scale multi-column system and a mAb capture process employing Protein A resin. The approach enables users to optimize MCC processes based on their internal preferences and constraints without requiring any mathematical modeling expertise.

  16. Monolithically integrated optical displacement sensor based on triangulation and optical beam deflection.

    PubMed

    Higurashi, E; Sawada, R; Ito, T

    1999-03-20

    A monolithically integrated optical displacement sensor based on triangulation and optical beam deflection is reported. This sensor is simple and consists of only a laser diode, a polyimide waveguide, and a split detector (a pair of photodiodes) upon a GaAs substrate. The resultant prototype device is extremely small (750 microm x 800 microm). Experiments have shown that this sensor can measure the displacement of a mirror with resolution of better than 4 nm. Additionally, we have experimentally demonstrated both axial and lateral displacement measurements when we used a cylindrical micromirror (diameter, 125 microm) as a movable external object. PMID:18305799

  17. Colloid transport in a heterogeneous partially saturated sand column.

    PubMed

    Mishurov, Mikhail; Yakirevich, Alexander; Weisbrod, Noam

    2008-02-15

    Colloid transport was studied in heterogeneous sand columns under unsaturated steady-state conditions, using two sizes of acid-cleaned sand to pack the column. Heterogeneity was created by placing three continuous tubes of fine sand (3.6% of the total volume) within a column of coarse sand (mean grain diameters 0.36 and 1.2 mm, respectively). Experiments were performed under three flow rates (0.1, 0.2, and 0.4 cm/ min) applied by a rain simulator atthe top of the column. Constant water-content profile in the coarse sand was achieved by applying corresponding suction at the column bottom. Three sizes of latex microspheres (1, 0.2, and 0.02 microm) and soluble tracers (LiBr), diluted in a weak base (pH 7.3, ionic strength 0.0023 M) solution, were used simultaneously. Introduction of preferential pathways reduced front-arrival time about 2-fold and increased colloid recovery which, at the 0.2 cm/min flow rate, was higher than at 0.4 and 0.1 cm/min. Maximum solution flux from coarse to fine sand (due to differences in matric pressure) at 0.2 cm/min, verified by hydrodynamic modeling, could explain this phenomenon. Results suggest that in heterogeneous soil, maximum colloid recovery does not necessarily occur at maximum water content. This has clear implications for colloid transport in natural soils, many of which are heterogeneous.

  18. Colloid transport in a heterogeneous partially saturated sand column.

    PubMed

    Mishurov, Mikhail; Yakirevich, Alexander; Weisbrod, Noam

    2008-02-15

    Colloid transport was studied in heterogeneous sand columns under unsaturated steady-state conditions, using two sizes of acid-cleaned sand to pack the column. Heterogeneity was created by placing three continuous tubes of fine sand (3.6% of the total volume) within a column of coarse sand (mean grain diameters 0.36 and 1.2 mm, respectively). Experiments were performed under three flow rates (0.1, 0.2, and 0.4 cm/ min) applied by a rain simulator atthe top of the column. Constant water-content profile in the coarse sand was achieved by applying corresponding suction at the column bottom. Three sizes of latex microspheres (1, 0.2, and 0.02 microm) and soluble tracers (LiBr), diluted in a weak base (pH 7.3, ionic strength 0.0023 M) solution, were used simultaneously. Introduction of preferential pathways reduced front-arrival time about 2-fold and increased colloid recovery which, at the 0.2 cm/min flow rate, was higher than at 0.4 and 0.1 cm/min. Maximum solution flux from coarse to fine sand (due to differences in matric pressure) at 0.2 cm/min, verified by hydrodynamic modeling, could explain this phenomenon. Results suggest that in heterogeneous soil, maximum colloid recovery does not necessarily occur at maximum water content. This has clear implications for colloid transport in natural soils, many of which are heterogeneous. PMID:18351073

  19. Do chimpanzees (Pan troglodytes) and 2-year-old children (Homo sapiens) understand double invisible displacement?

    PubMed

    Collier-Baker, Emma; Suddendorf, Thomas

    2006-05-01

    Chimpanzees (Pan troglodytes) and young children (Homo sapiens) have difficulty with double invisible displacements in which an object is hidden in two nonadjacent boxes in a linear array. Experiment 1 eliminated the possibility that chimpanzees' previous poor performance was due to the hiding direction of the displacement device. As in Call (2001), subjects failed double nonadjacent displacements, showing a tendency to select adjacent boxes. In Experiments 2 and 3, chimpanzees and 24-month-old children were tested on a new adaptation of the task in which four hiding boxes were presented in a diamond-shaped array on a vertical plane. Both species performed above chance on double invisible displacements using this format, suggesting that previous poor performance was due to a response bias or inhibition problem rather than a fundamental limitation in representational capacity.

  20. Alternating prism exposure causes dual adaptation and generalization to a novel displacement

    NASA Technical Reports Server (NTRS)

    Welch, Robert B.; Bridgeman, Bruce; Anand, Sulekha; Browman, Kaitlin E.

    1993-01-01

    In two experiments, we examined the hypothesis that repeatedly adapting and readapting to two mutually conflicting sensory environments fosters the development of a separate adaptation to each situation (dual adaptation) as well as an increased ability to adapt to a novel displacement (adaptive generalization). In the preliminary study, subjects alternated between adapting their visuomotor coordination to 30-diopter prismatic displacement and readapting to normal vision. Dual adaptation was observed by the end of 10 alternation cycles. However, an unconfounded test of adaptive generalization was prevented by an unexpected prism-adaptive shift in preexposure baselines for the dual-adapted subjects. In the primary experiment, the subjects adapted and readapted to opposite 15-diopter displacements for a total of 12 cycles. Both dual adaptation and adaptive generalization to a 30-diopter displacement were obtained. These findings may be understood in terms of serial reversal learning and 'learning to learn'.

  1. A liquid film model of tetrakaidecahedral packing to account for the establishment of epidermal cell columns.

    PubMed

    Menton, D N

    1976-05-01

    The possiblity that the organization of cells into columns in the mammalian epidermis may be a result of the close packing of these cells has been investigated in a model system involving the association of randomly produced soap bubbles into a stable froth. Upon floating to the surface of a liquid, soap bubbles have been found to spontaneously assemble into precise columns of interdigitating bubbles. The tetrakaidecahedral shape and the spatial configuration of these bubbles closely resemble those of stacked epidermal cells, although the columns of a froth were oriented at a 60degrees angle to their substratum rather than at right angles as occurs in the epidermal cell columns. These observations lend support to the theory that the organization of the cells in the epidermis into columns is due to the assumption of the keratocytes of a minimum surface-close packing array. Such an organizing mechanism would be independent of both positional control of the underlying mitoses and active guidance of the cells as they become superficially displaced within the epidermis. The observation that a high rate of cell turnover is incompatible with the epidermal column structure may be related to the finding that rapidly produced soap bubbles do not, at least initially, assemble into a columnar array. PMID:1270835

  2. Relevant signs of stable and unstable thoracolumbar vertebral column trauma

    SciTech Connect

    Gehweiler, J.A.; Daffner, R.H.; Osborne, R.L.

    1981-12-01

    One-hundred and seventeen patients with acute thoracolumbar vertebral column fracture or fracture-dislocations were analyzed and classified into stable (36%) and unstable (64%). Eight helpful roentgen signs were observed that may serve to direct attention to serious underlying, often occult, fractures and dislocations. The changes fall into four principal groups: abnormal soft tissues, abnormal vertebral alignment, abnormal joints, and widened vertebral canal. All stable and unstable lesions showed abnormal soft tissues, while 70% demonstrated kyphosis and/or scoliosis, and an abnormal adjacent intervertebral disk space. All unstable lesions showed one or more of the following signs: displaced vertebra, widened interspinous space, abnormal apophyseal joint(s), and widened vertebral canal.

  3. Quantification of the vocal folds’ dynamic displacements

    NASA Astrophysics Data System (ADS)

    del Socorro Hernández-Montes, María; Muñoz, Silvino; De La Torre, Manuel; Flores, Mauricio; Pérez, Carlos; Mendoza-Santoyo, Fernando

    2016-05-01

    Fast dynamic data acquisition techniques are required to investigate the motional behavior of the vocal folds (VFs) when they are subjected to a steady air-flow through the trachea. High-speed digital holographic interferometry (DHI) is a non-invasive full-field-of-view technique that has proved its usefulness to study rapid and non-repetitive object movements. Hence it is an ideal technique used here to measure VF displacements and vibration patterns at 2000 fps. Analyses from a set of 200 displacement images showed that VFs’ vibration cycles are established along their width (y) and length (x). Furthermore, the maximum deformation for the right and left VFs’ area may be quantified from these images, which in itself represents an important result in the characterization of this structure. At a controlled air pressure, VF displacements fall within the range ~100-1740 nm, with a calculated precision and accuracy that yields a variation coefficient of 1.91%. High-speed acquisition of full-field images of VFs and their displacement quantification are on their own significant data in the study of their functional and physiological behavior since voice quality and production depend on how they vibrate, i.e. their displacement amplitude and frequency. Additionally, the use of high speed DHI avoids prolonged examinations and represents a significant scientific and technological alternative contribution in advancing the knowledge and working mechanisms of these tissues.

  4. Conflict induced internal displacement in Nepal.

    PubMed

    Singh, Sonal; Sharma, Sharan Prakash; Mills, Edward; Poudel, Krishna C; Jimba, Masamine

    2007-01-01

    Nepal has witnessed a humanitarian crisis since the Maoist conflict began ten years ago. The plight of internally displaced persons (IDPs) in Nepal has received little international attention despite being rated one of the worst displacement scenarios in the world. An estimated 200,000 people have been displaced as a result of the conflict, with the far-western districts of Nepal being the worst affected. Internal displacement has stretched the carrying capacity of several cities with adverse physical and mental health consequences for the displaced. Vulnerable women and children have been the worst affected. The government has adopted a discriminatory approach and failed to fulfil its obligations towards IDPs. Non-governmental organisations and international agencies have provided inadequate services to IDPs in their programmes. Tackling the issues of IDPs requires co-operation between government and development agencies: acknowledging the burden of the problem of IDPs, adequate registration and needs assessment, along with health and nutritional surveys, and development of short-term emergency relief packages and long-term programmes for their assistance. PMID:17542185

  5. Ultra-Sensitive Magnetoresistive Displacement Sensing Device

    NASA Technical Reports Server (NTRS)

    Olivas, John D. (Inventor); Lairson, Bruce M. (Inventor); Ramesham, Rajeshuni (Inventor)

    2003-01-01

    An ultrasensitive displacement sensing device for use in accelerometers, pressure gauges, temperature transducers, and the like, comprises a sputter deposited, multilayer, magnetoresistive field sensor with a variable electrical resistance based on an imposed magnetic field. The device detects displacement by sensing changes in the local magnetic field about the magnetoresistive field sensor caused by the displacement of a hard magnetic film on a movable microstructure. The microstructure, which may be a cantilever, membrane, bridge, or other microelement, moves under the influence of an acceleration a known displacement predicted by the configuration and materials selected, and the resulting change in the electrical resistance of the MR sensor can be used to calculate the displacement. Using a micromachining approach, very thin silicon and silicon nitride membranes are fabricated in one preferred embodiment by means of anisotropic etching of silicon wafers. Other approaches include reactive ion etching of silicon on insulator (SOI), or Low Pressure Chemical Vapor Deposition of silicon nitride films over silicon substrates. The device is found to be improved with the use of giant magnetoresistive elements to detect changes in the local magnetic field.

  6. Performance of tuned liquid column dampers considering maximum liquid motion in seismic vibration control of structures

    NASA Astrophysics Data System (ADS)

    Chakraborty, Subrata; Debbarma, Rama; Marano, Giuseppe Carlo

    2012-03-01

    The optimum design of tuned liquid column damper (TLCD) is usually performed by minimizing the maximum response of structure subjected to stochastic earthquake load without imposing any restrictions on the possible maximum oscillation of the liquid within the vertical column. However, during strong earthquake motion, the maximum oscillation of vertical column of liquid may be equal to or greater than that of the container pipe. Consequently the physical behavior of the hydraulic system may change largely reducing its efficiency. The present study deals with the optimization of TLCD parameters to minimize the vibration effect of structures addressing the limitation on such excessive liquid displacement. This refers to the design of optimum TLCD system which not only assure maximum possible performance in terms of vibration mitigation, but also simultaneously put due importance to the natural constrained criterion of excessive lowering of liquid in the vertical column of TLCD. The constraint is imposed by limiting the maximum displacement of the liquid to the vertical height of the container. Numerical study is performed to elucidate the effect of constraint condition on the optimum parameters and overall performance of TLCD system of protection.

  7. Linear oil displacement by the emulsion entrapment process. [Dissertation

    SciTech Connect

    Schmidt, D.P.

    1982-01-01

    Lack of mobility control is one of the major impediments to successful enhanced oil recovery, especially for high viscosity oils. This work presents experimental and theoretical results for linear secondary oil displacements using dilute, stable suspensions of oil drops. The major hypothesis is that emulsions provide mobility control through entrapment or local permeability reduction, not through viscosity ratio improvement. In order to describe the displacement process, previous emulsion filtration theory is extended to longer cores and to two-phase flow. Quantitative agreement between theory and experiment is satisfactory for continuous secondary oil displacement with various drop-size emulsions in unconsolidated sand packs of permeabilities ranging from 0.7 ..mu..m/sup 2/ to 3.3 ..mu..m/sup 2/. Linear emulsion floods are shown to be most effective when the mean drop-size to pore-size ratio is in the region between straining and interception at the emulsion shock. Floods are more effective when the emulsion concentration is high which minimizes retention lag. Additionally, a parallel flooding apparatus is utilized to determine qualitatively the macroscopic benefits of emulsion mobility control. Direct analogies are established between augmented oil recovery with dilute emulsions and with entrapping polymers.

  8. Reproductive health: a right for refugees and internally displaced persons.

    PubMed

    Austin, Judy; Guy, Samantha; Lee-Jones, Louise; McGinn, Therese; Schlecht, Jennifer

    2008-05-01

    Continued political and civil unrest in low-resource countries underscores the ongoing need for specialised reproductive health services for displaced people. Displaced women particularly face high maternal mortality, unmet need for family planning, complications following unsafe abortion, and gender-based violence, as well as sexually transmitted diseases, including HIV. Relief and development agencies and UN bodies have developed technical materials, made positive policy changes specific to crisis settings and are working to provide better reproductive health care. Substantial gaps remain, however. The collaboration within the field of reproductive health in crises is notable, with many agencies working in one or more networks. The five-year RAISE Initiative brings together major UN and NGO agencies from the fields of relief and development, and builds on their experience to support reproductive health service delivery, advocacy, clinical training and research. The readiness to use common guidance documents, develop priorities jointly and share resources has led to smoother operations and less overlap than if each agency worked independently. Trends in the field, including greater focus on internally displaced persons and those living in non-camp settings, as well as refugees in camps, the protracted nature of emergencies, and an increasing need for empirical evidence, will influence future progress. PMID:18513603

  9. Reproductive health: a right for refugees and internally displaced persons.

    PubMed

    Austin, Judy; Guy, Samantha; Lee-Jones, Louise; McGinn, Therese; Schlecht, Jennifer

    2008-05-01

    Continued political and civil unrest in low-resource countries underscores the ongoing need for specialised reproductive health services for displaced people. Displaced women particularly face high maternal mortality, unmet need for family planning, complications following unsafe abortion, and gender-based violence, as well as sexually transmitted diseases, including HIV. Relief and development agencies and UN bodies have developed technical materials, made positive policy changes specific to crisis settings and are working to provide better reproductive health care. Substantial gaps remain, however. The collaboration within the field of reproductive health in crises is notable, with many agencies working in one or more networks. The five-year RAISE Initiative brings together major UN and NGO agencies from the fields of relief and development, and builds on their experience to support reproductive health service delivery, advocacy, clinical training and research. The readiness to use common guidance documents, develop priorities jointly and share resources has led to smoother operations and less overlap than if each agency worked independently. Trends in the field, including greater focus on internally displaced persons and those living in non-camp settings, as well as refugees in camps, the protracted nature of emergencies, and an increasing need for empirical evidence, will influence future progress.

  10. Measurement of displacement vector fields of extended objects

    NASA Astrophysics Data System (ADS)

    Osten, Wolfgang; Jüptner, Werner

    The main effort in laser metrology during the last 15 years has been focussed on the development of high precision phase measurement techniques, since the phase is the primary quantity for interferometrical testing. However, the phase distribution gives only a first impression of the deformation of the surface. In practice, the three-dimensional displacement components are required if the mechanical behaviour of the object under load is to be investigated. To calculate displacement components some further quantities are necessary, e.g. the three coordinates of the object points. Although the contour measurement can also be reduced to a phase measurement problem, the measurement of three-dimensional displacements is more complex than a high precision phase evaluation. From the practical point of view, four main tasks have to be performed: planning of the experiment, design of the interferometer, acquisition of data and evaluation of data. This paper deals with a discussion of the theoretical background of the last three procedures concerning the state of the art and describes some general rules as well as some problems remaining to be solved for the investigation of extended specimens.

  11. Periprosthetic fractures of the acetabulum during cup insertion: posterior column stability is crucial.

    PubMed

    Laflamme, G-Yves; Belzile, Etienne L; Fernandes, Julio C; Vendittoli, Pascal A; Hébert-Davies, Jonah

    2015-02-01

    Periprosthetic hip fractures around acetabular components are rare with little information available to guide surgical management of these complex injuries. A retrospective review of intraoperative isolated acetabular periprosthetic fractures from three tertiary surgical units was done. A total of 32 patients were identified with 9 initially missed. Acetabular components were stable (type 1) in 11 patients with no failures; unstable (type 2) in 12 patients and treated with supplemental fixation. Non-union and displacement were correlated with absent posterior column plating. Missed fractures (type 3) had the highest reoperation rate. Anterior patterns all healed, whereas fractures with posterior column instability had a 67% failure rate. Periprosthetic acetabular fracture can heal successfully with posterior column stability. Plating is mandatory for large posterior wall fragments to achieve osteointegration.

  12. Arsenate removal from water using sand--red mud columns.

    PubMed

    Genç-Fuhrman, Hülya; Bregnhøj, Henrik; McConchie, David

    2005-08-01

    This study describes experiments in which sorption filters, filled with chemically modified red mud (Bauxsol) or activated Bauxsol (AB) coated sand, are used to remove As(V) (arsenate) from water. Bauxsol-coated sand (BCS) and AB-coated sand (ABCS) are prepared by mixing Bauxsol or AB with wet sand and drying. Samples of the BCS and ABCS are also used in batch experiments to obtain isotherm data. The observed adsorption data fit the Langmuir model well, with adsorption maxima of 3.32 and 1.64 mgg(-1) at pH values of 4.5 and 7.1, respectively for BCS; and of 2.14 mgg(-1) for ABCS at a pH of 7.1. Test results show that higher arsenate adsorption capacities can be achieved for both BCS and ABCS when using the columns compared to results for batch experiments; the difference is greater for BCS. Additional batch tests, carried out for 21 days using BCS to explain the observed discrepancy, show that the equilibrium time previously used in batch experiments was too short because adsorption continued for at least 21 days and reached 87% after 21 days compared to only 35% obtained after 4h. Fixed bed column tests, used to investigate the effects of flow rate and initial arsenate concentration indicate that the process is sensitive to both parameters, with lower flow rates (longer effective residence times in the columns) and initial arsenate concentrations providing better column performance. An examination of the combined effect of potential competing anions (i.e. silicate, phosphate, sulphate and bicarbonate) on the column performance showed that the presence of these anions in tap water slightly decreases arsenate removal. Each breakthrough curve is compared to the Thomas model, and it is found that the model may be applied to estimate the arsenate sorption capacity in columns filled with BCS and ABCS. The data obtained from both batch and column studies indicate that BCS and ABCS filtration could be effectively used to remove arsenate from water, with the latter being

  13. The synthesis and characterization of a nuclear membrane affinity chromatography column for the study of human breast cancer resistant protein (BCRP) using nuclear membranes obtained from the LN-229 cells.

    PubMed

    Habicht, K-L; Frazier, C; Singh, N; Shimmo, R; Wainer, I W; Moaddel, R

    2013-01-01

    BCRP expression has been reported in glioblastoma cell lines and clinical specimens and has been shown to be expressed both in purified nuclei and in the soluble cytoplasmic fraction. To date, the nuclear BCRP has not been characterized. Our laboratory has previously developed an online chromatographic approach for the study of binding interactions between ligands and protein, cellular membrane affinity chromatography. To this end, we have immobilized the nuclear membrane fragments onto an immobilized artificial membrane stationary phase (IAM), resulting in the nuclear membrane affinity chromatography (NMAC) column. Initial characterization was carried out on the radio flow detector, as well as the LC-MSD, using frontal displacement chromatography techniques. Etoposide, a substrate for BCRP, was initially tested, to determine the functional immobilization of BCRP. Frontal displacement experiments with multiple concentrations of etoposide were run and the binding affinity was determined to be 4.54 μM, which is in close agreement with literature. The BCRP was fully characterized on the NMAC column and this demonstrates that for the first time the nuclear membranes have been successfully immobilized.

  14. Displacement Cascade Damage Production in Metals

    SciTech Connect

    Stoller, Roger E; Malerba, Lorenzo; Nordlund, Kai

    2015-01-01

    Radiation-induced changes in microstructure and mechanical properties in structural materials are the result of a complex set of physical processes initiated by the collision between an energetic particle (neutron or ion) and an atom in the lattice. This primary damage event is called an atomic displacement cascade. The simplest description of a displacement cascade is to view it as a series of many billiard-ball-like elastic collisions among the atoms in the material. This chapter describes the formation and evolution of this primary radiation damage mechanism to provide an overview of how stable defects are formed by displacement cascades, as well as the nature and morphology of the defects themselves. The impact of the relevant variables such as cascade energy and irradiation temperature is discussed, and defect formation in different materials is compared.

  15. Amorphization of silicon carbide by carbon displacement

    NASA Astrophysics Data System (ADS)

    Devanathan, R.; Gao, F.; Weber, W. J.

    2004-05-01

    We have used molecular dynamics simulations to examine the possibility of amorphizing silicon carbide (SiC) by exclusively displacing C atoms. At a defect generation corresponding to 0.2 displacements per atom, the enthalpy surpasses the level of melt-quenched SiC, the density decreases by about 15%, and the radial distribution function shows a lack of long-range order. Prior to amorphization, the surviving defects are mainly C Frenkel pairs (67%), but Si Frenkel pairs (18%) and antisite defects (15%) are also present. The results indicate that SiC can be amorphized by C sublattice displacements. Chemical short-range disorder, arising mainly from Frenkel pair production, plays a significant role in the amorphization.

  16. Forced displacement and women's security in Colombia.

    PubMed

    Meertens, Donny

    2010-04-01

    In the protracted Colombian conflict, assistance to internally displaced persons has developed in the context of contradictory political processes. The Colombian government's launching of a transitional justice process in the midst of armed conflict has generated a complex situation displaying both conflict and post-conflict characteristics. The progressive Constitutional Court rulings on internal displacement, in particular the gender-sensitive Auto 092, constitute an attempt to bring together humanitarian interventions and transitional justice measures in a rights-based framework. However, the national government is reluctant to adopt them fully and local realities still hamper their integrated implementation. Displaced women, therefore, remain in an especially vulnerable position. This paper argues that gender-sensitive humanitarian interventions must take into account all of these complexities of scale and political process in order to make legal frameworks more effective at the local level. In these contexts, interventions should pay particular attention to strategies that contribute to transforming pre-existing gender regimes. PMID:20132270

  17. Forced displacement and women's security in Colombia.

    PubMed

    Meertens, Donny

    2010-04-01

    In the protracted Colombian conflict, assistance to internally displaced persons has developed in the context of contradictory political processes. The Colombian government's launching of a transitional justice process in the midst of armed conflict has generated a complex situation displaying both conflict and post-conflict characteristics. The progressive Constitutional Court rulings on internal displacement, in particular the gender-sensitive Auto 092, constitute an attempt to bring together humanitarian interventions and transitional justice measures in a rights-based framework. However, the national government is reluctant to adopt them fully and local realities still hamper their integrated implementation. Displaced women, therefore, remain in an especially vulnerable position. This paper argues that gender-sensitive humanitarian interventions must take into account all of these complexities of scale and political process in order to make legal frameworks more effective at the local level. In these contexts, interventions should pay particular attention to strategies that contribute to transforming pre-existing gender regimes.

  18. Column Chromatography To Obtain Organic Cation Sorption Isotherms.

    PubMed

    Jolin, William C; Sullivan, James; Vasudevan, Dharni; MacKay, Allison A

    2016-08-01

    Column chromatography was evaluated as a method to obtain organic cation sorption isotherms for environmental solids while using the peak skewness to identify the linear range of the sorption isotherm. Custom packed HPLC columns and standard batch sorption techniques were used to intercompare sorption isotherms and solid-water sorption coefficients (Kd) for four organic cations (benzylamine, 2,4-dichlorobenzylamine, phenyltrimethylammonium, oxytetracycline) with two aluminosilicate clay minerals and one soil. A comparison of Freundlich isotherm parameters revealed isotherm linearity or nonlinearity was not significantly different between column chromatography and traditional batch experiments. Importantly, skewness (a metric of eluting peak symmetry) analysis of eluting peaks can establish isotherm linearity, thereby enabling a less labor intensive means to generate the extensive data sets of linear Kd values required for the development of predictive sorption models. Our findings clearly show that column chromatography can reproduce sorption measures from conventional batch experiments with the benefit of lower labor-intensity, faster analysis times, and allow for consistent sorption measures across laboratories with distinct chromatography instrumentation. PMID:27379799

  19. Column Chromatography To Obtain Organic Cation Sorption Isotherms.

    PubMed

    Jolin, William C; Sullivan, James; Vasudevan, Dharni; MacKay, Allison A

    2016-08-01

    Column chromatography was evaluated as a method to obtain organic cation sorption isotherms for environmental solids while using the peak skewness to identify the linear range of the sorption isotherm. Custom packed HPLC columns and standard batch sorption techniques were used to intercompare sorption isotherms and solid-water sorption coefficients (Kd) for four organic cations (benzylamine, 2,4-dichlorobenzylamine, phenyltrimethylammonium, oxytetracycline) with two aluminosilicate clay minerals and one soil. A comparison of Freundlich isotherm parameters revealed isotherm linearity or nonlinearity was not significantly different between column chromatography and traditional batch experiments. Importantly, skewness (a metric of eluting peak symmetry) analysis of eluting peaks can establish isotherm linearity, thereby enabling a less labor intensive means to generate the extensive data sets of linear Kd values required for the development of predictive sorption models. Our findings clearly show that column chromatography can reproduce sorption measures from conventional batch experiments with the benefit of lower labor-intensity, faster analysis times, and allow for consistent sorption measures across laboratories with distinct chromatography instrumentation.

  20. Theoretical and experimental study on regenerative rotary displacer Stirling engine

    SciTech Connect

    Raggi, L.; Katsuta, Masafumi; Isshiki, Naotsugu; Isshiki, Seita

    1997-12-31

    Recently a quite new type of hot air engine called rotary displacer engine, in which the displacer is a rotating disk enclosed in a cylinder, has been conceived and developed. The working gas, contained in a notch excavated in the disk, is heated and cooled alternately, on account of the heat transferred through the enclosing cylinder that is heated at one side and cooled at the opposite one. The gas temperature oscillations cause the pressure fluctuations that get out mechanical power acting on a power piston. In order to attempt to increase the performances for this kind of engine, the authors propose three different regeneration methods. The first one comprises two coaxial disks that, revolving in opposite ways, cause a temperature gradient on the cylinder wall and a regenerative axial heat conduction through fins shaped on the cylinder inner wall. The other two methods are based on the heat transferred by a proper closed circuit that in one case has a circulating liquid inside and in the other one is formed by several heat pipes working each one for different temperatures. An engine based on the first principle, the Regenerative Tandem Contra-Rotary Displacer Stirling Engine, has been realized and experimented. In this paper experimental results with and without regeneration are reported comparatively with a detailed description of the unity. A basic explanation of the working principle of this engine and a theoretical analysis investigating the main influential parameters for the regenerative effect are done. This new rotating displacer Stirling engines, for their simplicity, are expected to attain high rotational speed especially for applications as demonstration and hobby unities.

  1. Separation of the Carotenoid Bixin from Annatto Seeds Using Thin-Layer and Column Chromatography

    ERIC Educational Resources Information Center

    McCullagh, James V.; Ramos, Nicholas

    2008-01-01

    In this experiment the carotenoid bixin is isolated from annatto ("Bixa orellana") seeds using column chromatography. The experiment has several key advantages over previous pigment separation experiments. First, unlike other experiments significant quantities of the carotenoid (typically 20 to 25 mg) can be isolated from small quantities of plant…

  2. Frictional behavior of large displacement experimental faults

    USGS Publications Warehouse

    Beeler, N.M.; Tullis, T.E.; Blanpied, M.L.; Weeks, J.D.

    1996-01-01

    The coefficient of friction and velocity dependence of friction of initially bare surfaces and 1-mm-thick simulated fault gouges (400 mm at 25??C and 25 MPa normal stress. Steady state negative friction velocity dependence and a steady state fault zone microstructure are achieved after ???18 mm displacement, and an approximately constant strength is reached after a few tens of millimeters of sliding on initially bare surfaces. Simulated fault gouges show a large but systematic variation of friction, velocity dependence of friction, dilatancy, and degree of localization with displacement. At short displacement (<10 mm), simulated gouge is strong, velocity strengthening and changes in sliding velocity are accompanied by relatively large changes in dilatancy rate. With continued displacement, simulated gouges become progressively weaker and less velocity strengthening, the velocity dependence of dilatancy rate decreases, and deformation becomes localized into a narrow basal shear which at its most localized is observed to be velocity weakening. With subsequent displacement, the fault restrengthens, returns to velocity strengthening, or to velocity neutral, the velocity dependence of dilatancy rate becomes larger, and deformation becomes distributed. Correlation of friction, velocity dependence of friction and of dilatancy rate, and degree of localization at all displacements in simulated gouge suggest that all quantities are interrelated. The observations do not distinguish the independent variables but suggest that the degree of localization is controlled by the fault strength, not by the friction velocity dependence. The friction velocity dependence and velocity dependence of dilatancy rate can be used as qualitative measures of the degree of localization in simulated gouge, in agreement with previous studies. Theory equating the friction velocity dependence of simulated gouge to the sum of the friction velocity dependence of bare surfaces and the velocity

  3. Adsorption characteristics of methylene blue onto agricultural wastes lotus leaf in bath and column modes.

    PubMed

    Han, Xiuli; Wang, Wei; Ma, Xiaojian

    2011-01-01

    The adsorption potential of lotus leaf to remove methylene blue (MB) from aqueous solution was investigated in batch and fixed-bed column experiments. Langmuir, Freundlich, Temkin and Koble-Corrigan isotherm models were employed to discuss the adsorption behavior. The results of analysis indicated that the equilibrium data were perfectly represented by Temkin isotherm and the Langmuir saturation adsorption capacity of lotus leaf was found to be 239.6 mg g(-1) at 303 K. In fixed-bed column experiments, the effects of flow rate, influent concentration and bed height on the breakthrough characteristics of adsorption were discussed. The Thomas and the bed-depth/service time (BDST) models were applied to the column experimental data to determine the characteristic parameters of the column adsorption. The two models were found to be suitable to describe the dynamic behavior of MB adsorbed onto the lotus leaf powder column.

  4. Maxillary tooth displacement in the infratemporal fossa

    PubMed Central

    Roshanghias, Korosh; Peisker, Andre; Zieron, Jörg Olaf

    2016-01-01

    Wisdom tooth operations are sometimes accompanied by complications. This case report shows complications during upper jaw third molar removal. Expectable problems during oral surgery should be planned to be solved in advance. Displacement of the third molar during oral surgeries as a considerable complication is rarely discussed scientifically. A good design of flap, adequate power for extraction, and clear view on the surgical field are crucial. Three-dimensional radiographic diagnostics in terms of cone beam computed tomography is helpful after tooth displacement into the infratemporal fossa. PMID:27605997

  5. Delayed bone cement displacement following balloon kyphoplasty.

    PubMed

    Wang, Hee Sun; Kim, Hyeun Sung; Ju, Chang Il; Kim, Seok Won

    2008-04-01

    We report a rare case of delayed cement displacement after balloon kyphoplasty in patient with Kümmell's desease. A 78-year-old woman with Kümmell's desease at T12 level received percutaneous balloon kyphoplasty. Two months after surgery, the patient complained of progressive severe back pain. Computed tomographic scans revealed a breakdown of the anterior cortex and anterior displacement of bone cement. Although this complication is very rare, it is likely to occur in treatment of Kümmell's desease accompanying anterior cortical defect. PMID:19096648

  6. Maxillary tooth displacement in the infratemporal fossa.

    PubMed

    Roshanghias, Korosh; Peisker, Andre; Zieron, Jörg Olaf

    2016-01-01

    Wisdom tooth operations are sometimes accompanied by complications. This case report shows complications during upper jaw third molar removal. Expectable problems during oral surgery should be planned to be solved in advance. Displacement of the third molar during oral surgeries as a considerable complication is rarely discussed scientifically. A good design of flap, adequate power for extraction, and clear view on the surgical field are crucial. Three-dimensional radiographic diagnostics in terms of cone beam computed tomography is helpful after tooth displacement into the infratemporal fossa. PMID:27605997

  7. A novel wide measuring range FBG displacement sensor with variable measurement precision based on helical bevel gear

    NASA Astrophysics Data System (ADS)

    Jiang, Shan-chao; Wang, Jing; Sui, Qing-mei; Cao, Yu-qiang

    2015-03-01

    A novel fiber Bragg grating (FBG) displacement sensor is proposed, which can achieve wide measuring range displacement detection with variable measurement precision due to its mechanical transfer structure of helical bevel gear. A prototype is designed and fabricated. The maximum detection displacement of this prototype is 1.751 m, and the precision grade changes from 0.2% to 6.7%. Through analyzing the experiment data which is obtained in the calibration experiment, the measuring range of this sensor is from 0 m to 1.532 m, and the wavelength shift errors between experiment data and theory calculation are all less than 5%.

  8. Characterization of polyacrylamide based monolithic columns.

    PubMed

    Plieva, Fatima M; Andersson, Jonatan; Galaev, Igor Yu; Mattiasson, Bo

    2004-07-01

    Supermacroporous monolithic polyacrylamide (pAAm)-based columns have been prepared by radical cryo-copolymerization (copolymerization in the moderately frozen system) of acrylamide with functional co-monomer, allyl glycidyl ether (AGE), and cross-linker N,N'-methylene-bis-acrylamide (MBAAm) directly in glass columns (ID 10 mm). The monolithic columns have uniform supermacroporous sponge-like structure with interconnected supermacropores of pore size 5-100 microm. The monoliths can be dried and stored in the dry state. High mechanical stability of the monoliths allowed sterilization by autoclaving. Column-to-column reproducibility of pAAm-monoliths was demonstrated on 5 monolithic columns from different batches prepared under the same cryostructuration conditions.

  9. Characterization of polyacrylamide based monolithic columns.

    PubMed

    Plieva, Fatima M; Andersson, Jonatan; Galaev, Igor Yu; Mattiasson, Bo

    2004-07-01

    Supermacroporous monolithic polyacrylamide (pAAm)-based columns have been prepared by radical cryo-copolymerization (copolymerization in the moderately frozen system) of acrylamide with functional co-monomer, allyl glycidyl ether (AGE), and cross-linker N,N'-methylene-bis-acrylamide (MBAAm) directly in glass columns (ID 10 mm). The monolithic columns have uniform supermacroporous sponge-like structure with interconnected supermacropores of pore size 5-100 microm. The monoliths can be dried and stored in the dry state. High mechanical stability of the monoliths allowed sterilization by autoclaving. Column-to-column reproducibility of pAAm-monoliths was demonstrated on 5 monolithic columns from different batches prepared under the same cryostructuration conditions. PMID:15354560

  10. Influence of subcascade formation on displacement damage at high PKA energies

    SciTech Connect

    Stoller, R.E.; Greenwood, L.R.

    1997-08-01

    The design of first generation fusion reactors will have to be rely on radiation effects data obtained from experiments conducted in fission reactors. Two issues must be addressed to use this data with confidence. The first is differences in the neutron energy spectrum, and the second is differences in nuclear transmutation rates. Differences in the neutron energy spectra are reflected in the energy spectra of the primary knockon atoms (PKA). The issue of PKA energy effects has been addressed through the use of displacement cascade simulations using the method of molecular dynamics (MD). Although MD simulations can provide a detailed picture of the formation and evolution of displacement cascades, they impose a substantial computational burden. However, recent advances in computing equipment permit the simulation of high energy displacement events involving more than one-million atoms; the results presented here encompass MD cascade simulation energies from near the displacement threshold to as high as 40 keV. Two parameters have been extracted from the MD simulations: the number of point defects that remain after the displacement event is completed and the fraction of the surviving interstitials that are contained in clusters. The MD values have been normalized to the number of atomic displacements calculated with the secondary displacement model by Norgett, Robinson, and Torrens (NRT).

  11. Evaluation of optoelectronic Plethysmography accuracy and precision in recording displacements during quiet breathing simulation.

    PubMed

    Massaroni, C; Schena, E; Saccomandi, P; Morrone, M; Sterzi, S; Silvestri, S

    2015-08-01

    Opto-electronic Plethysmography (OEP) is a motion analysis system used to measure chest wall kinematics and to indirectly evaluate respiratory volumes during breathing. Its working principle is based on the computation of marker displacements placed on the chest wall. This work aims at evaluating the accuracy and precision of OEP in measuring displacement in the range of human chest wall displacement during quiet breathing. OEP performances were investigated by the use of a fully programmable chest wall simulator (CWS). CWS was programmed to move 10 times its eight shafts in the range of physiological displacement (i.e., between 1 mm and 8 mm) at three different frequencies (i.e., 0.17 Hz, 0.25 Hz, 0.33 Hz). Experiments were performed with the aim to: (i) evaluate OEP accuracy and precision error in recording displacement in the overall calibrated volume and in three sub-volumes, (ii) evaluate the OEP volume measurement accuracy due to the measurement accuracy of linear displacements. OEP showed an accuracy better than 0.08 mm in all trials, considering the whole 2m(3) calibrated volume. The mean measurement discrepancy was 0.017 mm. The precision error, expressed as the ratio between measurement uncertainty and the recorded displacement by OEP, was always lower than 0.55%. Volume overestimation due to OEP linear measurement accuracy was always <; 12 mL (<; 3.2% of total volume), considering all settings. PMID:26736504

  12. Results from the Portable Infrared Aerosol Transmission Experiment (PIRATE) - Caribbean: An examination of the column integrated infrared extinction of Saharan dust and comparisons with data commonly used in models

    NASA Astrophysics Data System (ADS)

    Thomas, M.; Gautier, C.

    2004-12-01

    Infrared optical depth of Saharan dust from field measurements made in Puerto Rico are presented and compared with frequently-used dust models. The Portable Infrared Aerosol Transmission Experiment (PIRATE) - Caribbean was a ground-based experiment that measured the infrared transmission of transportted dust from the Saharan Desert. A Fourier Transform Infrared (FTIR) spectrometer was used in Boqueron, Puerto Rico from June 23 through June 30, 2004 as a high-resolution infrared sun photometer. The visible aerosol optical depth (AOD) around the time of each FTIR measurement was taken from a nearby AERONET sensor at La Parguera, Puerto Rico, for reference. The FTIR recorded the direct solar and scattered radiances from 3 to 14 microns. By collecting the solar radiance for several days, some for which the AOD was either very low (<0.1) or high (>0.5), the infrared AOD of the dust was determined as a function of wavelength. The measured infrared AOD of the dust is compared with frequently-used dust models, i.e. Volz and Sokolik, for various effective radii and assumed dust compositions. Since Saharan dust is often pervasive over large regions of the globe, these results are potentially important in models and satellite measurements attempting to determine the regional forcing from dust.

  13. REDISTRIBUTOR FOR LIQUID-LIQUID EXTRACTION COLUMNS

    DOEpatents

    Bradley, J.G.

    1957-10-29

    An improved baffle plate construction to intimately mix immiscible liquid solvents for solvent extraction processes in a liquid-liquid pulse column is described. To prevent the light and heavy liquids from forming separate continuous homogeneous vertical channels through sections of the column, a baffle having radially placed rectangular louvers with deflection plates opening upon alternate sides of the baffle is placed in the column, normal to the axis. This improvement substantially completely reduces strippiig losses due to poor mixing.

  14. Distillation of light hydrocarbons in packed columns

    SciTech Connect

    Strigle, R.F.

    1985-04-01

    Newly developed design procedures have led to a wider acceptance of packed columns for distillation operations, especially those operating at atmospheric or higher pressures. Based on these new design methods, modern IMTP packing has been used in a wide variety of services to revamp over 300 distillation columns previously equipped with trays. A few of these columns are listed. These revamps were justified by capacity increase and by greater product recovery. In addition, energy savings were realized from reduction of reflux ratio.

  15. The Computational Properties of a Simplified Cortical Column Model.

    PubMed

    Cain, Nicholas; Iyer, Ramakrishnan; Koch, Christof; Mihalas, Stefan

    2016-09-01

    The mammalian neocortex has a repetitious, laminar structure and performs functions integral to higher cognitive processes, including sensory perception, memory, and coordinated motor output. What computations does this circuitry subserve that link these unique structural elements to their function? Potjans and Diesmann (2014) parameterized a four-layer, two cell type (i.e. excitatory and inhibitory) model of a cortical column with homogeneous populations and cell type dependent connection probabilities. We implement a version of their model using a displacement integro-partial differential equation (DiPDE) population density model. This approach, exact in the limit of large homogeneous populations, provides a fast numerical method to solve equations describing the full probability density distribution of neuronal membrane potentials. It lends itself to quickly analyzing the mean response properties of population-scale firing rate dynamics. We use this strategy to examine the input-output relationship of the Potjans and Diesmann cortical column model to understand its computational properties. When inputs are constrained to jointly and equally target excitatory and inhibitory neurons, we find a large linear regime where the effect of a multi-layer input signal can be reduced to a linear combination of component signals. One of these, a simple subtractive operation, can act as an error signal passed between hierarchical processing stages. PMID:27617444

  16. The Computational Properties of a Simplified Cortical Column Model

    PubMed Central

    Iyer, Ramakrishnan; Koch, Christof; Mihalas, Stefan

    2016-01-01

    The mammalian neocortex has a repetitious, laminar structure and performs functions integral to higher cognitive processes, including sensory perception, memory, and coordinated motor output. What computations does this circuitry subserve that link these unique structural elements to their function? Potjans and Diesmann (2014) parameterized a four-layer, two cell type (i.e. excitatory and inhibitory) model of a cortical column with homogeneous populations and cell type dependent connection probabilities. We implement a version of their model using a displacement integro-partial differential equation (DiPDE) population density model. This approach, exact in the limit of large homogeneous populations, provides a fast numerical method to solve equations describing the full probability density distribution of neuronal membrane potentials. It lends itself to quickly analyzing the mean response properties of population-scale firing rate dynamics. We use this strategy to examine the input-output relationship of the Potjans and Diesmann cortical column model to understand its computational properties. When inputs are constrained to jointly and equally target excitatory and inhibitory neurons, we find a large linear regime where the effect of a multi-layer input signal can be reduced to a linear combination of component signals. One of these, a simple subtractive operation, can act as an error signal passed between hierarchical processing stages. PMID:27617444

  17. 40 CFR 86.419-2006 - Engine displacement, motorcycle classes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Engine displacement, motorcycle... displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values... reference in § 86.1). (2) For rotary engines, displacement means the maximum volume of a combustion...

  18. 40 CFR 86.419-2006 - Engine displacement, motorcycle classes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Engine displacement, motorcycle... displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values... reference in § 86.1). (2) For rotary engines, displacement means the maximum volume of a combustion...

  19. 40 CFR 86.419-2006 - Engine displacement, motorcycle classes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Engine displacement, motorcycle... displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values... reference in § 86.1). (2) For rotary engines, displacement means the maximum volume of a combustion...

  20. Displacement Addition on Linking Extensional Fault Arrays in the Canyonlands Graben, Utah

    NASA Astrophysics Data System (ADS)

    Commins, D. C.; Gupta, S.; Cartwright, J. A.; Phillips, W. M.

    2003-12-01

    immediately following linkage, and recovery to a standard D-l profile is gained through this process. (5) The locus of displacement accumulation is not fixed in time; the central fault segment does not always experience the greatest displacement enhancement. Preliminary results of cosmogenic 10Be exposure dating of bedrock with quartz from the Permian Cedar Mesa Sandstone indicate recent (<10ka) timing of rapid displacement addition on linking faults.