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Sample records for accumulation solid partitioning

  1. Solids Accumulation Scouting Studies

    SciTech Connect

    Duignan, M. R.; Steeper, T. J.; Steimke, J. L.

    2012-09-26

    The objective of Solids Accumulation activities was to perform scaled testing to understand the behavior of remaining solids in a Double Shell Tank (DST), specifically AW-105, at Hanford during multiple fill, mix, and transfer operations. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles containing plutonium could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste staging tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids: Gibbsite, Zirconia, Sand, and Stainless Steel, with stainless steel particles representing the heavier particles, e.g., plutonium, and supernatant were charged to the test tank and rotating liquid jets were used to mix most of the solids while the simulant was pumped out. Subsequently, the volume and shape of the mounds of residual solids and the spatial concentration profiles for the surrogate for heavier particles were measured. Several techniques were developed and equipment designed to accomplish the measurements needed and they included: 1. Magnetic particle separator to remove simulant stainless steel solids. A device was designed and built to capture these solids, which represent the heavier solids during a waste transfer from a staging tank. 2. Photographic equipment to determine the volume of the solids mounds. The mounds were photographed as they were exposed at different tank waste levels to develop a composite of topographical areas. 3. Laser rangefinders to determine the volume of

  2. Whole shoot mineral partitioning and accumulation in pea (Pisum sativum)

    PubMed Central

    Sankaran, Renuka P.; Grusak, Michael A.

    2014-01-01

    Several grain legumes are staple food crops that are important sources of minerals for humans; unfortunately, our knowledge is incomplete with respect to the mechanisms of translocation of these minerals to the vegetative tissues and loading into seeds. Understanding the mechanism and partitioning of minerals in pea could help in developing cultivars with high mineral density. A mineral partitioning study was conducted in pea to assess whole-plant growth and mineral content and the potential source-sink remobilization of different minerals, especially during seed development. Shoot and root mineral content increased for all the minerals, although tissue-specific partitioning differed between the minerals. Net remobilization was observed for P, S, Cu, and Fe from both the vegetative tissues and pod wall, but the amounts remobilized were much below the total accumulation in the seeds. Within the mature pod, more minerals were partitioned to the seed fraction (>75%) at maturity than to the pod wall for all the minerals except Ca, where only 21% was partitioned to the seed fraction. Although there was evidence for net remobilization of some minerals from different tissues into seeds, continued uptake and translocation of minerals to source tissues during seed fill is as important, if not more important, than remobilization of previously stored minerals. PMID:24795736

  3. Whole shoot mineral partitioning and accumulation in pea (Pisum sativum).

    PubMed

    Sankaran, Renuka P; Grusak, Michael A

    2014-01-01

    Several grain legumes are staple food crops that are important sources of minerals for humans; unfortunately, our knowledge is incomplete with respect to the mechanisms of translocation of these minerals to the vegetative tissues and loading into seeds. Understanding the mechanism and partitioning of minerals in pea could help in developing cultivars with high mineral density. A mineral partitioning study was conducted in pea to assess whole-plant growth and mineral content and the potential source-sink remobilization of different minerals, especially during seed development. Shoot and root mineral content increased for all the minerals, although tissue-specific partitioning differed between the minerals. Net remobilization was observed for P, S, Cu, and Fe from both the vegetative tissues and pod wall, but the amounts remobilized were much below the total accumulation in the seeds. Within the mature pod, more minerals were partitioned to the seed fraction (>75%) at maturity than to the pod wall for all the minerals except Ca, where only 21% was partitioned to the seed fraction. Although there was evidence for net remobilization of some minerals from different tissues into seeds, continued uptake and translocation of minerals to source tissues during seed fill is as important, if not more important, than remobilization of previously stored minerals.

  4. Strain accumulation in quasicrystalline solids

    NASA Technical Reports Server (NTRS)

    Nori, Franco; Ronchetti, Marco; Elser, Veit

    1988-01-01

    The relaxation of two-dimensional quasicrystalline elastic networks when their constituent bonds are perturbed homogeneously is studied. Whereas ideal, quasi-periodic networks are stable against such perturbations, significant accumulations of strain in a class of disordered networks generated by a growth process are found. The grown networks are characterized by root mean square phason fluctuations which grow linearly with system size. The strain accumulation observed in these networks also grows linearly with system size. Finally, dependence of strain accumulation on cooling rate is found.

  5. Carbon Partitioning during Sucrose Accumulation in Sugarcane Internodal Tissue.

    PubMed

    Whittaker, A.; Botha, F. C.

    1997-12-01

    The temporal relationship between sucrose (Suc) accumulation and carbon partitioning was investigated in developing sugarcane internodes. Radiolabeling studies on tissue slices, which contained Suc concentrations ranging from 14 to 42% of the dry mass, indicated that maturation coincided with a redirection of carbon from water-insoluble matter, respiration, amino acids, organic acids, and phosphorylated intermediates into Suc. It is evident that a cycle of Suc synthesis and degradation exists in all of the internodes. The decreased allocation of carbon to respiration coincides with a decreased flux from the hexose pool. Both the glucose and fructose (Fru) concentrations significantly decrease during maturation. The phosphoenolpyruvate, Fru-6-phosphate (Fru-6-P), and Fru-2,6-bisphosphate (Fru-2, 6-P2) concentrations decrease between the young and older internodal tissue, whereas the inorganic phosphate concentration increases. The calculated mass-action ratios indicate that the ATP-dependent phosphofructokinase, pyruvate kinase, and Fru-1,6-bisphosphatase reactions are tightly regulated in all of the internodes, and no evidence was found that major changes in the regulation of any of these enzymes occur. The pyrophosphate-dependent phosphofructokinase reaction is in apparent equilibrium in all the internodes. Substrate availability might be one of the prime factors contributing to the observed decrease in respiration.

  6. Whole shoot mineral partitioning and accumulation in pea (Pisum sativum)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several grain legumes are staple food crops that are important sources of minerals for humans; unfortunately, our knowledge is incomplete with respect to the mechanisms of translocation of these minerals to the vegetative tissues and loading into seeds. Understanding the mechanism and partitioning o...

  7. Test Plan - Solids Accumulation Scouting Studies

    SciTech Connect

    Duignan, M. R.; Steeper, T. J.; Steimke, J. L.; Fowley, M. D.

    2012-05-10

    This plan documents the highlights of the Solids Accumulations Scouting Studies test; a project, from Washington River Protection Solutions (WRPS), that began on February 1, 2012. During the last 12 weeks considerable progress has been made to design and plan methods that will be used to estimate the concentration and distribution of heavy fissile solids in accumulated solids in the Hanford double-shell tank (DST) 241-AW-105 (AW-105), which is the primary goal of this task. This DST will be one of the several waste feed delivery staging tanks designated to feed the Pretreatment Facility (PTF) of the Waste Treatment and Immobilization Plant (WTP). Note that over the length of the waste feed delivery mission AW-105 is currently identified as having the most fill empty cycles of any DST feed tanks, which is the reason for modeling this particular tank. At SRNL an existing test facility, the Mixing Demonstration Tank, which will be modified for the present work, will use stainless steel particles in a simulant that represents Hanford waste to perform mock staging tanks transfers that will allow solids to accumulate in the tank heel. The concentration and location of the mock fissile particles will be measured in these scoping studies to produce information that will be used to better plan larger scaled tests. Included in these studies is a secondary goal of developing measurement methods to accomplish the primary goal. These methods will be evaluated for use in the larger scale experiments. Included in this plan are the several pretest activities that will validate the measurement techniques that are currently in various phases of construction. Aspects of each technique, e.g., particle separations, volume determinations, topographical mapping, and core sampling, have been tested in bench-top trials, as discussed herein, but the actual equipment to be employed during the full test will need evaluation after fabrication and integration into the test facility.

  8. The effect of solid metal composition on solid metal/ liquid metal partitioning of trace elements

    NASA Astrophysics Data System (ADS)

    Rai, N.; van Westrenen, W.

    2010-12-01

    Fundamental understanding of the partitioning behaviour of elements between different core and/or mantle phases is needed to constrain processes of planetary differentiation and evolution. The partitioning behaviour of elements between solid metal and liquid metal in the Fe-S system, of relevance to core crystallisation in planetesimals and the terrestrial planets, has been investigated by several workers [1-6], most of whom [1-5] conclude that variations in partition coefficients can be explained by variations in melt composition. However, recently Stewart et al. [6] showed that the crystal-lattice strain model commonly used to describe silicate mineral - silicate melt partitioning can be applied to partially molten metallic systems. This suggests the structure of the solid metal also plays a role in determining solid metal / molten metal partitioning. Here, we investigate the effect of the structure of the solid metal in the Fe-S system on solid/liquid metal partitioning by obtaining new element partitioning data at pressures between 0.5 and 3 GPa. The effect of the solid metal is isolated from pressure-temperature-melt composition effects by performing experiments at constant P and T with two Fe-S bulk compositions on either side of the eutectic composition. In addition to the effect of solid metal composition we investigate the effects of pressure and S content on trace element partitioning behaviour and the application of the lattice strain model to our results. Starting mixtures were doped with several hundred ppm levels of trace elements Ni, Co, W, Mo, V, Nb, Ta, Sn, Cu, Pb, Zn, Cr, Mn, P, Ge,. Experiments were performed using a QUICKPress piston cylinder apparatus at the VU University, Amsterdam using alumina capsules. Experiments were heated to 1073 K at pressure and allowed to sinter for a duration of 10 hours before the temperature was raised at a rate of 50 K / min to the target value. Preliminary EPMA data for a 1 GPa experiment with FeS as the solid

  9. Nitrogen retention and partitioning at the initiation of lipid accumulation in nitrogen-deficient algae.

    PubMed

    Adams, Curtis; Bugbee, Bruce

    2014-04-01

    Nitrogen (N) deficiency promotes lipid accumulation in many oleaginous algae, but we have a poor understanding of the associations between the initiation of lipid accumulation and algal N retention and partitioning. Here, we report on total cell N, five bulk pools of N in the cell (protein, free amino acids, DNA, RNA, chl), and lipids from N saturation to growth cessation in three species. While the maximum level of N uptake differed among species, the ratio of minimum retained N to N retained at the initiation of lipid accumulation was consistent among species at 0.5 ± 0.04. This suggests that the cellular initiation of lipid accumulation was associated with a common magnitude of N deficiency among species. Concerning the partitioning of N, the concentration of RNA and the protein to RNA ratio were most similar among species at the initiation of lipid accumulation with averages of 3.2 ± 0.26 g · L(-1) (8.2% variation) and 16 ± 1.5 (9.2% variation), respectively. All other pools and physiologically relevant ratios were considerably more variable. The species commonalities in RNA and protein show a similar reduction in general cellular function due to N deficiency before cellular initiation of lipid accumulation. These results provide insight into the physiological drivers for lipid accumulation in N-deficient algae and data for modeling these associations.

  10. Methamphetamine absorption by skin lipids: accumulated mass, partition coefficients, and the influence of fatty acids.

    PubMed

    Parker, K; Morrison, G

    2016-08-01

    Occupants of former methamphetamine laboratories, often residences, may experience increased exposure through the accumulation of the methamphetamine in the organic films that coat skin and indoor surfaces. The objectives of this study were to determine equilibrium partition coefficients of vapor-phase methamphetamine with artificial sebum (AS-1), artificial sebum without fatty acids (AS-2), and real skin surface films, herein called skin oils. Sebum and skin oil-coated filters were exposed to vapor-phase methamphetamine at concentrations ranging from 8 to 159 ppb, and samples were analyzed for exposure time periods from 2 h to 60 days. For a low vapor-phase methamphetamine concentration range of ~8-22 ppb, the equilibrium partition coefficient for AS-1 was 1500 ± 195 μg/g/ppb. For a high concentration range of 98-112 ppb, the partition coefficient was lower, 459 ± 80 μg/g/ppb, suggesting saturation of the available absorption capacity. The low partition coefficient for AS-2 (33 ± 6 μg/g/ppb) suggests that the fatty acids in AS-1 and skin oil are responsible for much high partition coefficients. We predict that the methamphetamine concentration in skin lipids coating indoor surfaces can exceed recommended surface remediation standards even for air concentrations well below 1 ppb.

  11. Heavy metal partitioning in a municipal solid waste incinerator

    SciTech Connect

    Sorum, L.; Fossum, M.; Hustad, J.E.; Evensen, E.

    1997-12-01

    Norway has the following priorities for management of municipal solid waste (MSW) (1) Reduce waste generation and toxic components in waste, (2) Encourage re-use, recycling and energy recovery, and (3) Secure an environmentally safe management of residues. MSW consists of household waste and waste from the service and trade industry delivered to municipal waste treatment plants or recycling schemes. In 1995, a total of 2.7 million tons of MSW (1.26 million tons of household waste and 1.44 million tons of waste from service and trade industry) was handled as follows: 68% was deposited on landfills, 18% was combusted, 13% recycled and 1% composted. Combustion of MSW is handled in five larger plants with energy recovery located in different cities in Norway. In addition, a new incinerator for MSW is planned. This incinerator will have to meet the new emission regulations given by the European Union which are more stringent than the present regulations. Hence, Norway is moving towards more stringent regulations, leading to an increased interest in the environmental aspects of MSW incinerators. During 1995 Trondheim Energy Company carried out an investigation program to examine the residues from the incinerator. Primary attention was on the heavy metals in the bottom ash, fly ash and the landfill leacate. The program was conducted in order to establish more information about characteristics of the residues and thus be able to undertake a sounder evaluation of the environmental aspects of the final treatment of these products. This program was supplementary to the emission analysis done periodically for the flue gas and drain water. The objective of this work has been to establish knowledge about the partitioning of heavy metals through the incinerator and calculate the concentrations of heavy metal in the input MSW.

  12. Accumulation of solid bodies in the solar nebula

    NASA Technical Reports Server (NTRS)

    Weidenschilling, S. J.; Davis, D. R.

    1987-01-01

    Research on the accumulation of solid bodies in the solar nebula is discussed. Studies of the earliest stage of accumulation of solid bodies in the solar system, which occured in the presence of the gaseous component of the solar nebula, are discussed. The combined effects of gas drag and gravitational perturbations of a planetary embryo on the orbital evolution of planetesimals, the effects of resonant trapping on planetesimals, and planetary mass accretion are discussed.

  13. Reverse energy partitioning-An efficient algorithm for computing the density of states, partition functions, and free energy of solids.

    PubMed

    Do, Hainam; Wheatley, Richard J

    2016-08-28

    A robust and model free Monte Carlo simulation method is proposed to address the challenge in computing the classical density of states and partition function of solids. Starting from the minimum configurational energy, the algorithm partitions the entire energy range in the increasing energy direction ("upward") into subdivisions whose integrated density of states is known. When combined with the density of states computed from the "downward" energy partitioning approach [H. Do, J. D. Hirst, and R. J. Wheatley, J. Chem. Phys. 135, 174105 (2011)], the equilibrium thermodynamic properties can be evaluated at any temperature and in any phase. The method is illustrated in the context of the Lennard-Jones system and can readily be extended to other molecular systems and clusters for which the structures are known.

  14. The Parameterization of Solid Metal-Liquid Metal Partitioning of Siderophile Elements

    NASA Technical Reports Server (NTRS)

    Chabot, N. L.; Jones, J. H.

    2003-01-01

    The composition of a metallic liquid can significantly affect the partitioning behavior of elements. For example, some experimental solid metal-liquid metal partition coefficients have been shown to increase by three orders of magnitude with increasing S-content of the metallic liquid. Along with S, the presence of other light elements, such as P and C, has also been demonstrated to affect trace element partitioning behavior. Understanding the effects of metallic composition on partitioning behavior is important for modeling the crystallization of magmatic iron meteorites and the chemical effects of planetary differentiation. It is thus useful to have a mathematical expression that parameterizes the partition coefficient as a function of the composition of the metal. Here we present a revised parameterization method, which builds on the theory of the current parameterization of Jones and Malvin and which better handles partitioning in multi-light-element systems.

  15. Actinide Partitioning and Radiation Effects in U(VI)-Solids: Thermodynamic & Mechanistic Study

    SciTech Connect

    Clark, Sue B.; Ewing, Rodney C.

    2010-05-20

    In most environmental systems, the mobility of a contaminant metal cation depends on its partitioning between the solid and solution phase. At the molecular level, partitioning to the solid phase is controlled by the coordination requirements of the contaminant cation. In this work, we developed linear free energy relationships (LFERs) to describe the partitioning of non-U actinide cations to U(VI) solid phases in a radiation environment; the LFERs are based on knowledge of the actinide coordination environment in or on the surface of the U(VI) solid, and the impact of ionizing radiation on the atomic interactions of the non-U actinide cations. LFERs were established for predicting (1) free energies of formation of pure U(VI) solids and solid solutions with non-U actinide cations, and (2) the adsorption of non-U actinide cations to pure U(VI) solids. We demonstrated the application of LFERs developed from knowledge of molecular structures of U(VI) solid phases to predict the predominance of U(VI) oxide hydrate and silicate solid phases as a function of geochemical conditions. We extended our efforts to define LFERs for U(VI) phosphate solids, and included the impact of actinide self-radiation on all LFERs for free energies of formation for U(VI) solids. We also defined LFERs for the formation of solid solutions between the U(VI) solids and non-U actinide cations such as Th, Np, Pu, Am, and Cm. We demonstrated the importance of nanocrystalline solids in the solid phase partitioning of these non-U actinide cations. For those solid solutions formed, we investigated the impact of ionizing radiation on the stability of those phases, and the release of the non-U actinide cations from the solids. Finally, developed LFERs to predict the adsorption of the non-U actinide cations to the surfaces of U(VI) oxide hydrates and U(VI) phosphates. We determined adsorption constants and coordination requirements for actinide adsorption to U(VI) solid phases. We determined

  16. EXPERIMENTAL METHODS TO ESTIMATE ACCUMULATED SOLIDS IN NUCLEAR WASTE TANKS

    SciTech Connect

    Duignan, M.; Steeper, T.; Steimke, J.

    2012-12-10

    The Department of Energy has a large number of nuclear waste tanks. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles, e.g., plutonium containing, could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids and supernatant were charged to the test tank and rotating liquid jets were used to remove most of the solids. Then the volume and shape of the residual solids and the spatial concentration profiles for the surrogate for plutonium were measured. This paper discusses the overall test results, which indicated heavy solids only accumulate during the first few transfer cycles, along with the techniques and equipment designed and employed in the test. Those techniques include: Magnetic particle separator to remove stainless steel solids, the plutonium surrogate from a flowing stream; Magnetic wand used to manually remove stainless steel solids from samples and the tank heel; Photographs were used to determine the volume and shape of the solids mounds by developing a composite of topographical areas; Laser rangefinders to determine the volume and shape of the solids mounds; Core sampler to determine the stainless steel solids distribution within the solids mounds; Computer driven positioner that placed the laser rangefinders and the core sampler over solids mounds that accumulated on the bottom of a scaled staging tank in locations where jet velocities were low. These

  17. Partitioning of Si and platinum group elements between liquid and solid Fe-Si alloys

    NASA Astrophysics Data System (ADS)

    Morard, G.; Siebert, J.; Badro, J.

    2014-05-01

    Crystallization of the Earth's inner core fractionates major and minor elements between the solid and liquid metal, leaving physical and geochemical imprints on the Earth's core. For example, the density jump observed at the Inner Core Boundary (ICB) is related to the preferential partitioning of lighter elements in the liquid outer core. The fractionation of Os, Re and Pt between liquid and solid during inner core crystallization has been invoked as a process that explains the observed Os isotopic signature of mantle plume-derived lavas (Brandon et al., 1998; Brandon and Walker, 2005) in terms of core-mantle interaction. In this article we measured partitioning of Si, Os, Re and Pt between liquid and solid metal. Isobaric (2 GPa) experiments were conducted in a piston-cylinder press at temperatures between 1250 °C and 1600 °C in which an imposed thermal gradient through the sample provided solid-liquid coexistence in the Fe-Si system. We determined the narrow melting loop in the Fe-Si system using Si partitioning values and showed that order-disorder transition in the Fe-Si solid phases can have a large effect on Si partitioning. We also found constant partition coefficients (DOs, DPt, DRe) between liquid and solid metal, for Si concentrations ranging from 2 to 12 wt%. The compact structure of Fe-Si liquid alloys is compatible with incorporation of Si and platinum group elements (PGEs) elements precluding solid-liquid fractionation. Such phase diagram properties are relevant for other light elements such as S and C at high pressure and is not consistent with inter-elemental fractionation of PGEs during metal crystallization at Earth's inner core conditions. We therefore propose that the peculiar Os isotopic signature observed in plume-derived lavas is more likely explained by mantle source heterogeneity (Meibom et al., 2002; Baker and Krogh Jensen, 2004; Luguet et al., 2008).

  18. Transfer functions for solid-solution partitioning of cadmium for Australian soils.

    PubMed

    de Vries, W; McLaughlin, M J; Groenenberg, J E

    2011-12-01

    To assess transport and ecotoxicological risks of metals, such as cadmium (Cd) in soils, models are needed for partitioning and speciation. We derived regression-based "partition-relations" based on adsorption and desorption experiments for main Australian soil types. First, batch adsorption experiments were carried out over a realistic range of dissolved Cd concentrations in agricultural soils in Australia. Results showed linear sorption relationships, implying the adequacy of using Kd values to describe partitioning. Desorption measurements were then carried out to assess in-situ Kd values and relate these to soil properties The best transfer functions for solid-solution partitioning were found for Kd values relating total dissolved Cd concentration to total soil Cd concentrations, accounting for the variation in pH, SOM contents and DOC concentrations. Model predictions compared well with measurements of an independent data set, but there was a tendency to underestimate dissolved Cd concentrations of highly polluted soils.

  19. Nonlocal effects on dynamic damage accumulation in brittle solids

    SciTech Connect

    Chen, E.P.

    1995-12-01

    This paper presents a nonlocal analysis of the dynamic damage accumulation processes in brittle solids. A nonlocal formulation of a microcrack based continuum damage model is developed and implemented into a transient dynamic finite element computer code. The code is then applied to the study of the damage accumulation process in a concrete plate with a central hole and subjected to the action of a step tensile pulse applied at opposite edges of the plate. Several finite element discretizations are used to examine the mesh size effect. Comparisons between calculated results based on local and nonlocal formulations are made and nonlocal effects are discussed.

  20. Hydrochloric acid aerosol and gaseous hydrogen chloride partitioning in a cloud contaminated by solid rocket exhaust

    NASA Technical Reports Server (NTRS)

    Sebacher, D. I.; Bendura, R. J.; Wornom, D. E.

    1980-01-01

    Partitioning of hydrogen chloride between hydrochloric acid aerosol and gaseous HCl in the lower atmosphere was experimentally investigated in a solid rocket exhaust cloud diluted with humid ambient air. Airborne measurements were obtained of gaseous HCl, total HCl, relative humidity and temperature to evaluate the conditions under which aerosol formation occurs in the troposphere in the presence of hygroscopic HCl vapor. Equilibrium predictions of HCl aerosol formation accurately predict the measured HCl partitioning over a range of total HCl concentrations from 0.6 to 16 ppm.

  1. Accumulation kinetics and equilibrium partitioning coefficients for semivolatile organic pollutants in forest litter.

    PubMed

    Nizzetto, Luca; Liu, Xiang; Zhang, Gan; Komprdova, Klara; Komprda, Jiri

    2014-01-01

    Soils are important stores of environmentally cycling semivolatile organic contaminants (SVOCs) and represent relevant atmospheric secondary sources whenever environmental conditions favor re-emission. The exchange between air and soil is controlled by resistances posed by interfacial matrices such as the ubiquitously distributed vegetation litter. For the first time, this study focused on the experimental characterization of accumulation parameters for SVOCs in litter under real field conditions. The logarithm of the litter-air equilibrium partitioning coefficient ranged 6.8-8.9 and had a similar dependence on logKOA as that of plant foliage and soil data. Uptake and release rates were also KOA dependent with values (relevant for real environmental conditions) ranging 30,000-150,000 d(-1) and 0.0004-0.0134 d(-1), respectively. The overall mass transfer coefficient v controlling litter-air exchange (0.03-1.4 cm s(-1)) was consistent with previously reported data of v for foliage in forest canopies after normalization on leaf area index. Obtained data suggest that litter holds the potential for influencing atmospheric fugacity in proximity to soil, likely affecting overall exchange of SVOCs between the soil reservoir and the atmosphere.

  2. Partitioned airs at microscale and nanoscale: thermal diffusivity in ultrahigh porosity solids of nanocellulose

    PubMed Central

    Sakai, Koh; Kobayashi, Yuri; Saito, Tsuguyuki; Isogai, Akira

    2016-01-01

    High porosity solids, such as plastic foams and aerogels, are thermally insulating. Their insulation performance strongly depends on their pore structure, which dictates the heat transfer process in the material. Understanding such a relationship is essential to realizing highly efficient thermal insulators. Herein, we compare the heat transfer properties of foams and aerogels that have very high porosities (97.3–99.7%) and an identical composition (nanocellulose). The foams feature rather closed, microscale pores formed with a thin film-like solid phase, whereas the aerogels feature nanoscale open pores formed with a nanofibrous network-like solid skeleton. Unlike the aerogel samples, the thermal diffusivity of the foam decreases considerably with a slight increase in the solid fraction. The results indicate that for suppressing the thermal diffusion of air within high porosity solids, creating microscale spaces with distinct partitions is more effective than directly blocking the free path of air molecules at the nanoscale. PMID:26830144

  3. Partitioned airs at microscale and nanoscale: thermal diffusivity in ultrahigh porosity solids of nanocellulose

    NASA Astrophysics Data System (ADS)

    Sakai, Koh; Kobayashi, Yuri; Saito, Tsuguyuki; Isogai, Akira

    2016-02-01

    High porosity solids, such as plastic foams and aerogels, are thermally insulating. Their insulation performance strongly depends on their pore structure, which dictates the heat transfer process in the material. Understanding such a relationship is essential to realizing highly efficient thermal insulators. Herein, we compare the heat transfer properties of foams and aerogels that have very high porosities (97.3–99.7%) and an identical composition (nanocellulose). The foams feature rather closed, microscale pores formed with a thin film-like solid phase, whereas the aerogels feature nanoscale open pores formed with a nanofibrous network-like solid skeleton. Unlike the aerogel samples, the thermal diffusivity of the foam decreases considerably with a slight increase in the solid fraction. The results indicate that for suppressing the thermal diffusion of air within high porosity solids, creating microscale spaces with distinct partitions is more effective than directly blocking the free path of air molecules at the nanoscale.

  4. Partitioning, persistence, and accumulation in digested sludge of the topical antiseptic triclocarban during wastewater treatment.

    PubMed

    Heidler, Jochen; Sapkota, Amir; Halden, Rolf U

    2006-06-01

    The topical antiseptic agent triclocarban (TCC) is a common additive in many antimicrobial household consumables, including soaps and other personal care products. Long-term usage of the mass-produced compound and a lack of understanding of its fate during sewage treatment motivated the present mass balance analysis conducted at a typical U.S. activated sludge wastewater treatment plant featuring a design capacity of 680 million liters per day. Using automated samplers and grab sampling, the mass of TCC contained in influent, effluent, and digested sludge was monitored by isotope dilution liquid chromatography (tandem) mass spectrometry. The average mass of TCC (mean +/- standard deviation) entering and exiting the plant in influent (6.1 +/- 2.0 microg/L) and effluent (0.17 +/- 0.03 microg/ L) was 3737 +/- 694 and 127 +/- 6 g/d, respectively, indicating an aqueous-phase removal efficiency of 97 +/- 1%. Tertiary treatment by chlorination and sand filtration provided no detectable benefit to the overall removal. Due to strong sorption of TCC to wastewater particulate matter (78 +/- 11% sorbed), the majority of the TCC mass was sequestered into sludge in the primary and secondary clarifiers of the plant. Anaerobic digestion for 19 days did not promote TCC transformation, resulting in an accumulation of the antiseptic compound in dewatered, digested municipal sludge to levels of 51 +/- 15 mg/kg dry weight (2815 +/- 917 g/d). In addition to the biocide mass passing through the plant contained in the effluent (3 +/- 1%), 76 +/- 30% of the TCC input entering the plant underwent no net transformation and instead partitioned into and accumulated in municipal sludge. Based on the rate of beneficial reuse of sludge produced by this facility (95%), which exceeds the national average (63%), study results suggest that approximately three-quarters of the mass of TCC disposed of by consumers in the sewershed of the plant ultimately is released into the environment by application

  5. Prerequisites for application of hyperbolic relaxed eddy accumulation on managed grasslands and alternative net ecosystem exchange flux partitioning

    NASA Astrophysics Data System (ADS)

    Riederer, M.; Hübner, J.; Ruppert, J.; Brand, W. A.; Foken, T.

    2014-12-01

    Relaxed eddy accumulation is still applied in ecosystem sciences for measuring trace gas fluxes. On managed grasslands, the length of time between management events and the application of relaxed eddy accumulation has an essential influence on the determination of the proportionality factor b and thus on the resulting flux. In this study this effect is discussed for the first time. Also, scalar similarity between proxy scalars and scalars of interest is affected until the ecosystem has completely recovered. Against this background, CO2 fluxes were continuously measured and 13CO2 isofluxes were determined with a high measurement precision on two representative days in summer 2010. Moreover, a common method for the partitioning of the net ecosystem exchange into assimilation and respiration based on temperature and light response was compared with an isotopic approach directly based on the isotope discrimination of the biosphere. This approach worked well on the grassland site and could enhance flux partitioning results by better reproducing the environmental conditions.

  6. Solid solution partitioning of Sr 2+, Ba 2+, and Cd 2+ to calcite

    NASA Astrophysics Data System (ADS)

    Tesoriero, Anthony J.; Pankow, James F.

    1996-03-01

    Although solid solutions play important roles in controlling the concentrations of minor metal ions in natural waters, uncertainties regarding their compositions, thermodynamics, and kinetics usually prevent them from being considered. A range of precipitation rates was used here to study the nonequilibrium and equilibrium partitioning behaviors of Sr 2+, Ba 2+, and Cd 2+ to calcite (CaCO 3(s)). The distribution coefficient of a divalent metal ion Me 2+ for partitioning from an aqueous solution into calcite is given by DMe = ( XMeCO 3(s)/[Me 2+])/( XCaCO 3(s)/[Ca 2+]). The X values are solid-phase mole fractions; the bracketed values are the aqueous molal concentrations. In agreement with prior work, at intermediate to high precipitation rates R (nmol/mg-min), DSr, DBa, and DCd were found to depend strongly on R. At low R, the values of DSr, DBa, and DCd became constant with R. At 25 °C, the equilibrium values for DSr, DBa, and DCd for dilute solid solutions were estimated to be 0.021 ± 0.003, 0.012 ± 0.005, and 1240 ± 300, respectively. Calculations using these values were made to illustrate the likely importance of partitioning of these ions to calcite in groundwater systems. Due to its large equilibrium DMe value, movement of Cd 2+ will be strongly retarded in aquifers containing calcite; Sr 2+ and Ba 2+ will not be retarded nearly as much.

  7. Solid solution partitioning of Sr2+, Ba2+, and Cd2+ to calcite

    USGS Publications Warehouse

    Tesoriero, A.J.; Pankow, J.F.

    1996-01-01

    Although solid solutions play important roles in controlling the concentrations of minor metal ions in natural waters, uncertainties regarding their compositions, thermodynamics, and kinetics usually prevent them from being considered. A range of precipitation rates was used here to study the nonequilibrium and equilibrium partitioning behaviors of Sr2+, Ba2+, and Cd2+ to calcite (CaCO3(s)). The distribution coefficient of a divalent metal ion Me2+ for partitioning from an aqueous solution into calcite is given by DMe = (XMeCO3(s)/[Me2+])/(XCaCO3(s)/[Ca 2+]). The X values are solid-phase mole fractions; the bracketed values are the aqueous molal concentrations. In agreement with prior work, at intermediate to high precipitation rates R (nmol/mg-min), DSr, DBa, and DCd were found to depend strongly on R. At low R, the values of DSr, DBa, and DCd became constant with R. At 25??C, the equilibrium values for DSr, DBa, and DCd for dilute solid solutions were estimated to be 0.021 ?? 0.003, 0.012 ?? 0.005, and 1240 ?? 300, respectively. Calculations using these values were made to illustrate the likely importance of partitioning of these ions to calcite in groundwater systems. Due to its large equilibrium DMe value, movement of Cd2+ will be strongly retarded in aquifers containing calcite; Sr2+ and Ba2+ will not be retarded nearly as much.

  8. Neptunium(V) partitioning to uranium(VI) oxide and peroxide solids.

    PubMed

    Douglas, Matthew; Clark, Sue B; Friese, Judah I; Arey, Bruce W; Buck, Edgar C; Hanson, Brady D

    2005-06-01

    Metaschoepite, [(UO2)8O2(OH)12] x 10H2O, and metastudtite, UO4 x 4H2O, are alteration phases anticipated in a spent nuclear fuel repository following the moist oxidation of UO2 on a geologic time scale. Dissolved concentrations and hence potential mobility of other radionuclides in the fuel, such as the neptunyl cation (NpO2+), will likely be determined by the extent of their partitioning into these U(VI) solids. 237Np is of particular interest due to its potential high mobility and long half-life (2.1 x 10(6) years.) In this study, metaschoepite has been precipitated and subsequently transformed to studtite in the presence of dissolved Np. The metaschoepite and studtite solids that formed initially contained <10 and 6500 ppm Np, respectively. Batch dissolution studies of these solids at pH 6 demonstrate release of Np that exceeds congruent dissolution of U from metastudtite; furthermore, the released Np cation remains in solution. Thus, although the Np partitions into the metastudtite solid initially, it is released to solution over time, indicating that metastudtite is not likely to serve as a host solid for Np incorporation or sorption of the neptunyl cation on long time scales.

  9. Endocrine activity of persistent organic pollutants accumulated in human silicone implants--Dosing in vitro assays by partitioning from silicone.

    PubMed

    Gilbert, Dorothea; Mayer, Philipp; Pedersen, Mikael; Vinggaard, Anne Marie

    2015-11-01

    Persistent organic pollutants (POPs) accumulated in human tissues may pose a risk for human health by interfering with the endocrine system. This study establishes a new link between actual human internal POP levels and the endocrine active dose in vitro, applying partitioning-controlled dosing from silicone to the H295R steroidogenesis assay: (1) Measured concentrations of POPs in silicone breast implants were taken from a recent study and silicone disks were loaded according to these measurements. (2) Silicone disks were transferred into H295R cell culture plates in order to control exposure of the adrenal cells by equilibrium partitioning. (3) Hormone production of the adrenal cells was measured as toxicity endpoint. 4-Nonylphenol was used for method development, and the new dosing method was compared to conventional solvent-dosing. The two dosing modes yielded similar dose-dependent hormonal responses of H295R cells. However, with the partitioning-controlled freely dissolved concentrations (Cfree) as dose metrics, dose-response curves were left-shifted by two orders of magnitude relative to spiked concentrations. Partitioning-controlled dosing of POPs resulted in up to 2-fold increases in progestagen and corticosteroid levels at Cfree of individual POPs in or below the femtomolar range. Silicone acted not only as source of the POPs but also as a sorption sink for lipophilic hormones, stimulating the cellular hormone production. Methodologically, the study showed that silicone can be used as reference partitioning phase to transfer in vivo exposure in humans (silicone implants) to in vitro assays (partition-controlled dosing). The main finding was that POPs at the levels at which they are found in humans can interfere with steroidogenesis in a human adrenocortical cell line.

  10. Accumulation and sub-cellular partitioning of metals and As in the clam Venerupis corrugata: Different strategies towards different elements.

    PubMed

    Velez, Cátia; Figueira, Etelvina; Soares, Amadeu M V M; Freitas, Rosa

    2016-08-01

    The main goal of the present study was to assess accumulation, tolerance and sub-cellular partitioning of As, Hg, Cd and Pb in Venerupis corrugata. Results showed an increase of elements accumulation in V. corrugata with the increase of exposure. However, organisms presented higher capacity to accumulate Hg, Cd and Pb (BCF ≥ 12.8) than As (BCF ≤ 2.1) and higher accumulation rate for Cd and Pb than for Hg and As. With the increase of Hg exposure concentrations clams tended to increase the amount of metal bound to metal-sensitive fractions, which may explain the mortality recorded at the highest exposure concentration. Cd sub-cellular partitioning showed that with the increase of exposure concentrations V. corrugata increased the amount of metal in the cellular debris fraction, probably bound to the cellular membranes which explain the mortality recorded at the highest concentration. Results on As partitioning demonstrated that most of the metalloid was associated with fractions in the biologically detoxified metal compartment (BDM). Since high mortality was observed in clams exposed to As our results may indicate that this strategy was not enough to prevent clams from toxic effects and mortality occurred. When exposed to Pb most of the metal was in the BDM compartment, but in this case the metal was mostly in the metal-rich granules fraction which seemed to be efficient in preventing clams from toxicity, and no mortality was recorded. Our study further revealed that As and Hg were the most available elements to be biomagnified through the food chain.

  11. Uncertainties associated with lacking data for predictions of solid-solution partitioning of metals in soil.

    PubMed

    Le, T T Yen; Hendriks, A Jan

    2014-08-15

    Soil properties, i.e., pH and contents of soil organic matter (SOM), dissolved organic carbon (DOC), clay, oxides, and reactive metals, are required inputs to both mechanistic and empirical modeling in assessing metal solid-solution partitioning. Several of these properties are rarely measured in site-specific risk assessment. We compared the uncertainties induced by lacking data on these soil properties in estimating metal soil solution concentrations. The predictions by the Orchestra framework were more sensitive to lacking soil property data than the predictions by the transfer functions. The deviations between soil solution concentrations of Cd, Ni, Zn, Ba, and Co estimated with measured SOM and those estimated with generic SOM by the Orchestra framework were about 10 times larger than the deviations in the predictions by the transfer functions. High uncertainties were induced by lacking data in assessing solid-solution partitioning of oxy-anions like As, Mo, Sb, Se, and V. Deviations associated with lacking data in predicting soil solution concentrations of these metals by the Orchestra framework reached three-to-six orders of magnitude. The solid-solution partitioning of metal cations was strongly influenced by pH and contents of organic matter, oxides, and reactive metals. Deviations of more than two orders of magnitude were frequently observed between the estimates of soil solution concentrations with the generic values of these properties and the estimates based on the measured data. Reliable information on these properties is preferred to be included in the assessment by either the Orchestra framework or transfer functions.

  12. Microcarbon residue yield and heteroatom partitioning between volatiles and solids for whole vacuum resids and their liquid chromatographic fractions

    SciTech Connect

    Green, J.B.; Shay, J.Y.; Reynolds, J.W.; Green, J.A.; Young, L.L.; White, M.E.

    1993-10-01

    Five petroleum >1000{degrees}F resids were separated into compound type fractions using liquid chromatography. The coking tendency of each compound type was assessed using the microcarbon residue (MCR) test (ASTM D 4530). Heteroatom (N, S, Ni, V) partitioning between MCR solids versus volatiles was determined through analysis of the starting fractions and the corresponding MCR solids. The weighted sum of MCR solid yields over all compound types in a given resid was typically in good agreement with the MCR yield of the whole resid. This finding agrees with prior studies indicating coke yield to be an additive property. Sulfur partitioning was also an additive property, was predictable from MCR yield, and was nearly independent of the initial form (sulfide, thiophenic, sulfoxide) present. Nitrogen and nickel partitioning were nonadditive and therefore composition dependent. Partitioning of vanadium into solids was essentially quantitative for all resids and their fractions. MCR solid yield was generally dependent only on H/C ratio. However, there is some evidence indicating secondary dependence on hydrocarbon structure; i.e., that naphthenic rings reduce MCR in proportion to H/C by virtue of their effective hydrogen transfer properties. Deposition of N and Ni into MCR solids over the fractions was often appreciably less than that of the whole resids, thereby indicating that interaction among various compound types was required for maximum incorporation of those elements into coke.

  13. Partitioning the grapevine growing season in the Douro Valley of Portugal: accumulated heat better than calendar dates.

    PubMed

    Real, António C; Borges, José; Cabral, J Sarsfield; Jones, Gregory V

    2015-08-01

    Temperature and water status profiles during the growing season are the most important factors influencing the ripening of wine grapes. To model weather influences on the quality and productivity of the vintages, it is necessary to partition the growing season into smaller growth intervals in which weather variables are evaluated. A significant part of past and ongoing research on the relationships between weather and wine quality uses calendar-defined intervals to partition the growing season. The phenology of grapevines is not determined by calendar dates but by several factors such as accumulated heat. To examine the accuracy of different approaches, this work analyzed the difference in average temperature and accumulated precipitation using growth intervals with boundaries defined by means of estimated historical phenological dates and intervals defined by means of accumulated heat or average calendar dates of the Douro Valley of Portugal. The results show that in situations where there is an absence of historical phenological dates and/or no available data that makes the estimation of those dates possible, it is more accurate to use grapevine heat requirements than calendar dates to define growth interval boundaries. Additionally, we analyzed the ability of the length of growth intervals with boundaries based on grapevine heat requirements to differentiate the best from the worst vintage years with the results showing that vintage quality is strongly related to the phenological events. Finally, we analyzed the variability of growth interval lengths in the Douro Valley during 1980-2009 with the results showing a tendency for earlier grapevine physiology.

  14. Biodegradation of Endocrine Disruptors in Solid-Liquid Two-Phase Partitioning Systems by Enrichment Cultures

    PubMed Central

    dos Santos, Silvia Cristina Cunha; Ouellette, Julianne; Juteau, Pierre; Lépine, François; Déziel, Eric

    2013-01-01

    Naturally occurring and synthetic estrogens and other molecules from industrial sources strongly contribute to the endocrine disruption of urban wastewater. Because of the presence of these molecules in low but effective concentrations in wastewaters, these endocrine disruptors (EDs) are only partially removed after most wastewater treatments, reflecting the presence of these molecules in rivers in urban areas. The development of a two-phase partitioning bioreactor (TPPB) might be an effective strategy for the removal of EDs from wastewater plant effluents. Here, we describe the establishment of three ED-degrading microbial enrichment cultures adapted to a solid-liquid two-phase partitioning system using Hytrel as the immiscible water phase and loaded with estrone, estradiol, estriol, ethynylestradiol, nonylphenol, and bisphenol A. All molecules except ethynylestradiol were degraded in the enrichment cultures. The bacterial composition of the three enrichment cultures was determined using 16S rRNA gene sequencing and showed sequences affiliated with bacteria associated with the degradation of these compounds, such as Sphingomonadales. One Rhodococcus isolate capable of degrading estrone, estradiol, and estriol was isolated from one enrichment culture. These results highlight the great potential for the development of TPPB for the degradation of highly diluted EDs in water effluents. PMID:23728808

  15. Experimental Method Development for Estimating Solid-phase Diffusion Coefficients and Material/Air Partition Coefficients of SVOCs

    EPA Science Inventory

    The solid-phase diffusion coefficient (Dm) and material-air partition coefficient (Kma) are key parameters for characterizing the sources and transport of semivolatile organic compounds (SVOCs) in the indoor environment. In this work, a new experimental method was developed to es...

  16. Quantitative Trait Loci and Inter-Organ Partitioning for Essential Metal and Toxic Analogue Accumulation in Barley

    PubMed Central

    Reuscher, Stefan; Kolter, Andreas; Hoffmann, Astrid; Pillen, Klaus

    2016-01-01

    The concentrations of both essential nutrients and chemically similar toxic analogues accumulated in cereal grains have a major impact on the nutritional quality and safety of crops. Naturally occurring genetic diversity can be exploited for the breeding of improved varieties through introgression lines (ILs). In this study, multi-element analysis was conducted on vegetative leaves, senesced flag leaves and mature grains of a set of 54 ILs of the wild ancestral Hordeum vulgare ssp. spontaneum in the cultivated variety Hordeum vulgare ssp. vulgare cv. Scarlett. Plants were cultivated on an anthropogenically heavy metal-contaminated soil collected in an agricultural field, thus allowing simultaneous localization of quantitative trait loci (QTL) for the accumulation of both essential nutrients and toxic trace elements in barley as a model cereal crop. For accumulation of the micronutrients Fe and Zn and the interfering toxin Cd, we identified 25, 16 and 5 QTL, respectively. By examining the gene content of the introgressions, we associated QTL with candidate genes based on homology to known metal homeostasis genes of Arabidopsis and rice. Global comparative analyses suggested the preferential remobilization of Cu and Fe, over Cd, from the flag leaf to developing grains. Our data identifies grain micronutrient filling as a regulated and nutrient-specific process, which operates differently from vegetative micronutrient homoeostasis. In summary, this study provides novel QTL for micronutrient accumulation in the presence of toxic analogues and supports a higher degree of metal specificity of trace element partitioning during grain filling in barley than previously reported for other cereals. PMID:27078500

  17. [Effect of fertilization on the absorption, partition and accumulation of carbon and nitrogen of rice under the equal N conditions].

    PubMed

    Feng, Lei; Tong, Cheng-Li; Shi, Hui; Wu, Jin-Shui; Li, Yong; Huang, Tie-Ping; Xia, Hai-Ao

    2011-02-01

    In this study, the assimilation, partition and accumulation of carbon (C) and nitrogen (N), as well as the relationship between C and N accumulation of rice, were studied from typical paddy ecosystems under long-term fertilizer applications with equal N inputs in subtropical China. The results showed that chemical fertilizer plus low organic manure (LOM) could promote effectively the distribution of C in the rice plant. The N content in the stem-leaf and grain of rice under organic-inorganic fertilization was 8.9-10.2 g x kg(-1) and 11.9-14.8 g x kg(-1) respectively. It was much higher than under other treatments, with about 13% - 53% and 9% - 19% higher than under the chemical fertilization (NPK), separately and 12% - 77% and 23% - 32% higher than under the control treatment (CK), respectively. The C and N storages of rice were mainly accumulated in the aboveground part. Organic-inorganic fertilization treatment possessed higher storages of C (3467.8-4 323.9 kg x hm(-2)) and N (120.3-135.2 kg x hm(-2)) in the rice grain,which was about 13% - 23% of C and 26% - 45% of N higher than under NPK treatment. It indicated that rice grain was the main sink of C and N. The organic-inorganic fertilization was in favor of C accumulation and N absorption in the rice plant and it still possesses an obvious potential in C and N sequestration and absorption in subtropical paddy field.

  18. Nitrogen accumulation and partitioning in a High Arctic tundra ecosystem from extreme atmospheric N deposition events.

    PubMed

    Choudhary, Sonal; Blaud, Aimeric; Osborn, A Mark; Press, Malcolm C; Phoenix, Gareth K

    2016-06-01

    Arctic ecosystems are threatened by pollution from recently detected extreme atmospheric nitrogen (N) deposition events in which up to 90% of the annual N deposition can occur in just a few days. We undertook the first assessment of the fate of N from extreme deposition in High Arctic tundra and are presenting the results from the whole ecosystem (15)N labelling experiment. In 2010, we simulated N depositions at rates of 0, 0.04, 0.4 and 1.2 g Nm(-2)yr(-1), applied as (15)NH4(15)NO3 in Svalbard (79(°)N), during the summer. Separate applications of (15)NO3(-) and (15)NH4(+) were also made to determine the importance of N form in their retention. More than 95% of the total (15)N applied was recovered after one growing season (~90% after two), demonstrating a considerable capacity of Arctic tundra to retain N from these deposition events. Important sinks for the deposited N, regardless of its application rate or form, were non-vascular plants>vascular plants>organic soil>litter>mineral soil, suggesting that non-vascular plants could be the primary component of this ecosystem to undergo measurable changes due to N enrichment from extreme deposition events. Substantial retention of N by soil microbial biomass (70% and 39% of (15)N in organic and mineral horizon, respectively) during the initial partitioning demonstrated their capacity to act as effective buffers for N leaching. Between the two N forms, vascular plants (Salix polaris) in particular showed difference in their N recovery, incorporating four times greater (15)NO3(-) than (15)NH4(+), suggesting deposition rich in nitrate will impact them more. Overall, these findings show that despite the deposition rates being extreme in statistical terms, biologically they do not exceed the capacity of tundra to sequester pollutant N during the growing season. Therefore, current and future extreme events may represent a major source of eutrophication.

  19. Determination of pesticides in lettuce using solid-liquid extraction with low temperature partitioning.

    PubMed

    Costa, Anna I G; Queiroz, Maria E L R; Neves, Antônio A; de Sousa, Flaviane A; Zambolim, Laércio

    2015-08-15

    This work describes the optimization and validation of a method employing solid-liquid extraction with low temperature partitioning (SLE/LTP) together with analysis by gas chromatography with electron capture detection (GC/ECD) for the determination of nine pesticides (chlorothalonil, methyl parathion, procymidone, endosulfan, iprodione, λ-cyhalothrin, permethrin, cypermethrin, and deltamethrin) in lettuce. The method was found to be selective, accurate, and precise, with means recovery values in the range of 72.3-103.2%, coefficients of variation ⩽ 12%, and detection limits in the range 0.4-37 μg kg(-1). The matrix components significantly influence the chromatographic response of the analytes (above 10%). The optimized and validated method was applied to determine the residual concentrations of the fungicides iprodione and procymidone that had been applied to field crops of lettuce. The maximum residual concentrations of the pesticides in the lettuce samples were 13.6 ± 0.4 mg kg(-1) (iprodione) and 1.00 ± 0.01 mg kg(-1) (procymidone), on the day after application of the products.

  20. Hyphenating Centrifugal Partition Chromatography with Nuclear Magnetic Resonance through Automated Solid Phase Extraction.

    PubMed

    Bisson, Jonathan; Brunel, Marion; Badoc, Alain; Da Costa, Grégory; Richard, Tristan; Mérillon, Jean-Michel; Waffo-Téguo, Pierre

    2016-10-18

    Centrifugal partition chromatography (CPC) and all countercurrent separation apparatus provide chemists with efficient ways to work with complex matrixes, especially in the domain of natural products. However, despite the great advances provided by these techniques, more efficient ways of analyzing the output flow would bring further enhancement. This study describe a hyphenated approach made by coupling NMR with CPC through a hybrid-indirect coupling made possible by using a solid phase extraction (SPE) apparatus intended for high-pressure liquid chromatography (HPLC)-NMR hyphenation. Some hardware changes were needed to adapt the incompatible flow-rates and a reverse-engineering approach that led to the specific software required to control the apparatus. 1D (1)HNMR and (1)H-(1)H correlation spectroscopy (COSY) spectra were acquired in reasonable time without the need for any solvent-suppression method thanks to the SPE nitrogen drying step. The reduced usage of expensive deuterated solvents from several hundreds of milliliters to the milliliter order is the major improvement of this approach compared to the previously published ones.

  1. Development of a full automation solid phase microextraction method for investigating the partition coefficient of organic pollutant in complex sample.

    PubMed

    Jiang, Ruifen; Lin, Wei; Wen, Sijia; Zhu, Fang; Luan, Tiangang; Ouyang, Gangfeng

    2015-08-07

    A fully automated solid phase microextraction (SPME) depletion method was developed to study the partition coefficient of organic compound between complex matrix and water sample. The SPME depletion process was conducted by pre-loading the fiber with a specific amount of organic compounds from a proposed standard gas generation vial, and then desorbing the fiber into the targeted samples. Based on the proposed method, the partition coefficients (Kmatrix) of 4 polyaromatic hydrocarbons (PAHs) between humic acid (HA)/hydroxypropyl-β-cyclodextrin (β-HPCD) and aqueous sample were determined. The results showed that the logKmatrix of 4 PAHs with HA and β-HPCD ranged from 3.19 to 4.08, and 2.45 to 3.15, respectively. In addition, the logKmatrix values decreased about 0.12-0.27 log units for different PAHs for every 10°C increase in temperature. The effect of temperature on the partition coefficient followed van't Hoff plot, and the partition coefficient at any temperature can be predicted based on the plot. Furthermore, the proposed method was applied for the real biological fluid analysis. The partition coefficients of 6 PAHs between the complex matrices in the fetal bovine serum and water were determined, and compared to ones obtained from SPME extraction method. The result demonstrated that the proposed method can be applied to determine the sorption coefficients of hydrophobic compounds between complex matrix and water in a variety of samples.

  2. Experimental determination of the partitioning of gallium between solid iron metal and synthetic basaltic melt Electron and ion microprobe study

    NASA Technical Reports Server (NTRS)

    Drake, M. J.; Newsom, H. E.; Reed, S. J. B.; Enright, M. C.

    1984-01-01

    The distribution of Ga between solid Fe metal and synthetic basaltic melt is investigated experimentally at temperatures of 1190 and 1330 C, and over a narrow range of oxygen fugacities. Metal-silicate reversal experiments were conducted, indicating a close approach to equilibrium. The analysis of the partitioned products was performed using electron and ion microprobes. At one bar total pressure, the solid metal/silicate melt partition coefficient D(Ga) is used to evaluate metal-silicate fractionation processes in the earth, moon, and Eucrite Parent Body (EPB). It is found that the depletion of Ga abundances in the EPB is due to the extraction of Ga into a metallic core. Likewise, the depletion of Ga in the lunar mantle is consistent with the extraction of Ga into a smaller lunar core if Ga was originally present in a subchondritic concentration. The relatively high Ga abundances in the earth's mantle are discussed, with reference to several theoretical models.

  3. An added-mass partition algorithm for fluid–structure interactions of compressible fluids and nonlinear solids

    SciTech Connect

    Banks, J.W. Henshaw, W.D. Kapila, A.K. Schwendeman, D.W.

    2016-01-15

    We describe an added-mass partitioned (AMP) algorithm for solving fluid–structure interaction (FSI) problems involving inviscid compressible fluids interacting with nonlinear solids that undergo large rotations and displacements. The computational approach is a mixed Eulerian–Lagrangian scheme that makes use of deforming composite grids (DCG) to treat large changes in the geometry in an accurate, flexible, and robust manner. The current work extends the AMP algorithm developed in Banks et al. [1] for linearly elasticity to the case of nonlinear solids. To ensure stability for the case of light solids, the new AMP algorithm embeds an approximate solution of a nonlinear fluid–solid Riemann (FSR) problem into the interface treatment. The solution to the FSR problem is derived and shown to be of a similar form to that derived for linear solids: the state on the interface being fundamentally an impedance-weighted average of the fluid and solid states. Numerical simulations demonstrate that the AMP algorithm is stable even for light solids when added-mass effects are large. The accuracy and stability of the AMP scheme is verified by comparison to an exact solution using the method of analytical solutions and to a semi-analytical solution that is obtained for a rotating solid disk immersed in a fluid. The scheme is applied to the simulation of a planar shock impacting a light elliptical-shaped solid, and comparisons are made between solutions of the FSI problem for a neo-Hookean solid, a linearly elastic solid, and a rigid solid. The ability of the approach to handle large deformations is demonstrated for a problem of a high-speed flow past a light, thin, and flexible solid beam.

  4. Dietary accumulation and depuration of hydrophobic organochlorines: Bioaccumulation parameters and their relationship with the octanol/water partition coefficient

    SciTech Connect

    Fisk, A.T.; Norstrom, R.J.; Cymbalisty, C.D.; Muir, D.C.G.

    1998-01-01

    Dietary accumulation of 23 hydrophobic organochlorines (OCs) by juvenile rainbow trout (Oncorhynchus mykiss) was studied with the objective of obtaining relationships between bioaccumulation parameters and the octanol/water partition coefficient (K{sub ow}). A wide range of OCs were used including 16 polychlorinated biphenyls, hexachlorobenzene, mirex, tris(4-chlorophenyl)methane (TCPMe), tris(4-chlorophenyl)methanol (TCPMeOH), and three toxaphene congeners. With the exception of TCPMeOH, Cl{sub 7}-CHB, and PCB 18, all of the OCs had biomagnification factors (BMFs) >1, implying a potential to biomagnify. Half-lives had a significant curvilinear relationship with K{sub ow} (R{sup 2} = 0.85, p < 0.001), with a maximum t{sub 1/2} for OCs with log K{sub ow} {approximately}7.0. Decreasing t{sub 1/2} for OCs of log K{sub ow} > 7.0 may be related to slow kinetics of these super hydrophobic OCs and the short exposure phase, which results in insufficient time for the super hydrophobic OCs to reach slower clearing compartments of the rainbow trout. Assimilation efficiency was not as well described by K{sub ow} as by t{sub 1/2} and BMF, although a significant curvilinear relationship was observed (R{sup 2} = 0.53, p = 0.004). The BMF had a significant curvilinear relationship with K{sub ow} (R{sup 2} = 0.84, p < 0.001). Recalcitrant OCs with a log K{sub ow} of {approximately}7.0 would appear to have the greatest potential for food chain biomagnification in fish.

  5. Transformation of ferulic acid to vanillin using a fed-batch solid-liquid two-phase partitioning bioreactor.

    PubMed

    Ma, Xiao-kui; Daugulis, Andrew J

    2014-01-01

    Amycolatopsis sp. ATCC 39116 (formerly Streptomyces setonii) has shown promising results in converting ferulic acid (trans-4-hydroxy-3-methoxycinnamic acid; substrate), which can be derived from natural plant wastes, to vanillin (4-hydroxy-3-methoxybenzaldehyde). After exploring the influence of adding vanillin at different times during the growth cycle on cell growth and transformation performance of this strain and demonstrating the inhibitory effect of vanillin, a solid-liquid two-phase partitioning bioreactor (TPPB) system was used as an in situ product removal technique to enhance transformation productivity by this strain. The thermoplastic polymer Hytrel(®) G4078W was found to have superior partitioning capacity for vanillin with a partition coefficient of 12 and a low affinity for the substrate. A 3-L working volume solid-liquid fed-batch TPPB mode, using 300 g Hytrel G4078W as the sequestering phase, produced a final vanillin concentration of 19.5 g/L. The overall productivity of this reactor system was 450 mg/L. h, among the highest reported in literature. Vanillin was easily and quantitatively recovered from the polymers mostly by single stage extraction into methanol or other organic solvents used in food industry, simultaneously regenerating polymer beads for reuse. A polymer-liquid two phase bioreactor was again confirmed to easily outperform single phase systems that feature inhibitory or easily further degraded substrates/products. This enhancement strategy might reasonably be expected in the production of other flavor and fragrance compounds obtained by biotransformations.

  6. Assessment of accumulated fatigue damage in solid plates using nonlinear Lamb wave approach

    NASA Astrophysics Data System (ADS)

    Deng, Mingxi; Pei, Junfeng

    2007-03-01

    The feasibility of using the nonlinear effect of primary Lamb wave propagation for assessing accumulated fatigue damage in solid plates is theoretically analyzed. After the aluminum sheets are subjected to tension-tension fatigue loading for different numbers of loading cycles, they are subjected to ultrasonic tests near the driving frequency where Lamb waves have a strong nonlinearity. This is followed by the measurement of the amplitude-frequency curves for second harmonics of the considered Lamb waves. The experimental results show that the effect of second-harmonic generation by Lamb wave propagation is very sensitive to the accumulation of fatigue damage of solid plates.

  7. Arsenic solid-phase partitioning in reducing sediments of a contaminated wetland

    SciTech Connect

    Wilkin, Richard T.; Ford, Robert G.

    2008-10-06

    The geochemical partitioning of arsenic in organic-rich sediments from a contaminated wetland is examined using X-ray absorption spectroscopy and selective chemical extraction procedures, and evaluated in context to the anoxic diagenesis of iron and sulfur. The interaction between ground water and surface water has a significant influence on iron sulfide formation in the wetland sediments. Ground-water seeps supply concentrations of sulfate, dissolved hydrocarbons, ferrous iron, and arsenic, and sediments located near seeps are anomalously enriched in arsenic, reactive iron, and acid-volatile sulfides. Degree-of-sulfidation (DOS) values are high in sediments adjacent to sites of ground-water discharge, ranging from 0.57 to 1.0. Pyrite (FeS{sub 2}) formation is apparently not limited by the abundance of any one primary reactant, e.g., organic carbon, sulfate, or reactive iron; instead, persistence of precursor iron monosulfides is attributed to slow pyrite formation kinetics due to low concentrations of reactive intermediate sulfur species or possibly due to high concentrations of arsenite, dissolved organic-carbon, or other solutes that adsorb to iron monosulfides surfaces and impede transformation reactions to pyrite. Greigite (Fe{sub 3}S{sub 4}) accounts for > 80% of total reduced sulfur in sediments rich in acid-volatile sulfide and X-ray absorption spectroscopy data for magnetic separates provide direct evidence that As(III) is, at least in part, associated with reduced sulfur in the form of greigite. However, pyrite can only account for a small percentage, < 20%, of the total arsenic budget in the reduced sediments. Although pyrite is the predicted stable endpoint for reactive iron and sulfur, it appears that within a 30 y time period pyrite is a relatively unimportant host for arsenic in the system investigated here. The abundance of reactive iron in the sediments prevents accumulation of dissolved sulfide and thus prevents formation of soluble thioarsenic

  8. Experimental Methods to Estimate Accumulated Solids in Nuclear Waste Tanks - 13313

    SciTech Connect

    Duignan, Mark R.; Steeper, Timothy J.; Steimke, John L.

    2013-07-01

    The Department of Energy has a large number of nuclear waste tanks. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles, e.g., plutonium containing, could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids and supernatant were charged to the test tank and rotating liquid jets were used to remove most of the solids. Then the volume and shape of the residual solids and the spatial concentration profiles for the surrogate for plutonium were measured. This paper discusses the overall test results, which indicated heavy solids only accumulate during the first few transfer cycles, along with the techniques and equipment designed and employed in the test. Those techniques include: - Magnetic particle separator to remove stainless steel solids, the plutonium surrogate from a flowing stream. - Magnetic wand used to manually remove stainless steel solids from samples and the tank heel. - Photographs were used to determine the volume and shape of the solids mounds by developing a composite of topographical areas. - Laser range finders to determine the volume and shape of the solids mounds. - Core sampler to determine the stainless steel solids distribution within the solids mounds. - Computer driven positioner that placed the laser range finders and the core sampler over solids mounds that accumulated on the bottom of a scaled staging tank in locations where jet velocities

  9. Ionic liquid expedites partition of curcumin into solid gel phase but discourages partition into liquid crystalline phase of 1,2-dimyristoyl-sn-glycero-3-phosphocholine liposomes.

    PubMed

    El Khoury, Elsy D; Patra, Digambara

    2013-08-22

    The hydrolysis of curcumin in alkaline and neutral buffer conditions is of interest because of the therapeutic applicability of curcumin. We show that hydrolysis of curcumin can be remarkably suppressed in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) liposomes. The fluorescence of curcumin sensitively detects the phase transition temperature of liposomes. However, at greater concentrations, curcumin affects the phase transition temperature, encouraging fusion of two membrane phases. The interaction of curcumin with DMPC is found to be strong, with a partition coefficient value of Kp = 2.78 × 10(5) in the solid gel phase, which dramatically increases in the liquid crystalline phase to Kp = 1.15 × 10(6). The importance of ionic liquids as green solvents has drawn interest because of their toxicological effect on human health; however, the impact of ionic liquids (ILs) on liposomes is not yet understood. The present study establishes that ILs such as 1-methyl-3-octylimidazolium chloride (moic) affect the permeability and fluidity of liposomes and thus influence parition of curcumin into DMPC liposomes, helping in the solid gel phase but diminishing in the liquid crystalline phase. The Kp value of curcumin does not change appreciably with moic concentration in the solid gel state but decreases with moic concentration in the liquid crystalline phase. Curcumin, a rotor sensitive to detect phase transition temperature, is applied to investigate the influence of ionic liquids such as 1-methyl-3-octylimidazolium chloride, 1-buytl-3-methyl imadazolium tetrafluoroborate, and 1-benzyl-3-methyl imidazolium tetrafluoroborate on DMPC liposome properties. 1-Methyl-3-octylimidazolium chloride lowers the phase transition temperature, but 1-buytl-3-methyl imidazolium tetrafluoroborate and 1-benzyl-3-methyl imidazolium tetrafluoroborate do not perceptibly modify the phase transition temperature; rather, they broaden the phase transition.

  10. Soret separation of highly siderophile elements in Fe-Ni-S melts: Implications for solid metal-liquid metal partitioning

    NASA Astrophysics Data System (ADS)

    Brenan, James M.; Bennett, Neil

    2010-10-01

    Soret separation of melts consisting of Fe (+ 1-10 wt.% Ni) with added C, Si or S and trace highly siderophile elements (HSE; Ru, Rh, Pd, Re, Os, Ir, Pt and Au) was investigated in experiments done at 2 GPa, T hot ~ 2000 °C and T hot-T cold ~ 250 °C. Experiments with added C and Si produced homogeneous samples, whereas those with S resulted in significant compositional gradients, with S enriched at the hot end of the sample, and Fe and HSE enriched at the cold end. The magnitude of the separation of the HSE is not the same for each, but varies in the order (smallest to largest) Pd~Ausolid metal-liquid metal partitioning can be captured in a single thermal diffusion experiment. The magnitude of the melt composition effect, as judged by the Jones-Malvin interaction parameter, β, varies with metal size in a manner similar to solid metal-liquid metal partition coefficients, suggesting like origins of the HSE "selectivity" for Fe-rich solid or liquid structures.

  11. Damage accumulation in ion-irradiated Ni-based concentrated solid-solution alloys

    DOE PAGES

    Ullah, Mohammad W.; Aidhy, Dilpuneet S.; Zhang, Yanwen; ...

    2016-01-01

    We investigate Irradiation-induced damage accumulation in Ni0.8Fe0.2 and Ni0.8Cr0.2 alloys by using molecular dynamics simulations to assess possible enhanced radiation-resistance in these face-centered cubic (fcc), single-phase, concentrated solid-solution alloys, as compared with pure fcc Ni.

  12. The electric field in spontaneously heating accumulations of solid combustible minerals

    SciTech Connect

    Aleksandrov, I.V.

    1982-01-01

    The electric field in the ionic circuit in a spontaneously heating stack of cutter peat has been studied and modeled. On the basis of laboratory and industrial investigations and a theoretical analysis, the desirability has been shown of representing spontaneously heating accumulations of solid combustible minerals as macrogalvanic cells with spontaneous discharge.

  13. Sugar loss and enzyme inhibition due to oligosaccharides accumulation during high solids-loading enzymatic hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, ammonia fiber expansion: AFEX and extractive ammonia: EA). The methodology for large-scale separation of ...

  14. ARSENIC SOLID-PHASE PARTITIONING IN REDUCING SEDIMENTS OF CONTAMINATED WETLAND

    EPA Science Inventory

    The geochemical partitioning of arsenic in organic-rich sediments from a contaminated wetland is examined using X-ray absorption spectroscopy and selective chemical extraction procedures, and evaluated in context to the anoxic diagenesis of iron and sulfur. The interaction betwe...

  15. [Coupling effects of partitioning alternative drip irrigation with plastic mulch and nitrogen fertilization on cotton dry matter accumulation and nitrogen use].

    PubMed

    Li, Pei-Ling; Zhang, Fu-Cang

    2013-02-01

    A field experiment with complete combination design was conducted to study the effects of partitioning alternative drip irrigation with plastic mulch and nitrogen fertilization on the dry matter accumulation and nitrogen use efficiency of cotton plant. Three levels of irrigation (260, 200, and 140 mm) and of nitrogen fertilizer (270, 180, and 90 kg.hm-2) were installed. The cotton dry mass was the highest in treatments medium nitrogen/high water and high nitrogen/high water. As compared with that in high nitrogen/high water treatment, the nitrogen use efficiency for dry matter accumulation in medium nitrogen/high water treatment was increased by 34.0% -44.6%, with an average of 34.7% , while the water use efficiency was decreased by 6.4% -10.7%, averagely 10.2%. As for the nitrogen accumulation in cotton plant, the nitrogen use efficiency was the highest in medium nitrogen/high water treatment, and the water use efficiency was the highest in high nitrogen/medium water treatment. Compared with high nitrogen/high water treatment, medium nitrogen/high water treatment increased the nitrogen use efficiency for cotton nitrogen accumulation by 29.0% -41.7%, but decreased the water use efficiency for cotton nitrogen accumulation by 5.5%-14.0%. Among the treatments of coupling water and nitrogen of higher cotton yield, treatment medium nitrogen/high water had the higher cotton nitrogen recovery rate, nitrogen agronomic efficiency, and apparent use efficiency than the treatments high nitrogen/medium water and high nitrogen/high water, but no significant differences were observed in the nitrogen absorption ratio and nitrogen physiological efficiency. Treatment medium nitrogen/high water was most beneficial to the coupling effects of water and nitrogen under partitioning alternate drip irrigation with plastic mulch and nitrogen fertilization.

  16. Damage accumulation in ion-irradiated Ni-based concentrated solid-solution alloys

    SciTech Connect

    Ullah, Mohammad W.; Aidhy, Dilpuneet S.; Zhang, Yanwen; Weber, William J.

    2016-01-01

    We investigate Irradiation-induced damage accumulation in Ni0.8Fe0.2 and Ni0.8Cr0.2 alloys by using molecular dynamics simulations to assess possible enhanced radiation-resistance in these face-centered cubic (fcc), single-phase, concentrated solid-solution alloys, as compared with pure fcc Ni.

  17. Modeled Sources, Transport, and Accumulation of Dissolved Solids in Water Resources of the Southwestern United States

    USGS Publications Warehouse

    Anning, D.W.

    2011-01-01

    Information on important source areas for dissolved solids in streams of the southwestern United States, the relative share of deliveries of dissolved solids to streams from natural and human sources, and the potential for salt accumulation in soil or groundwater was developed using a SPAtially Referenced Regressions On Watershed attributes model. Predicted area-normalized reach-catchment delivery rates of dissolved solids to streams ranged from <10(kg/year)/km2 for catchments with little or no natural or human-related solute sources in them to 563,000(kg/year)/km2 for catchments that were almost entirely cultivated land. For the region as a whole, geologic units contributed 44% of the dissolved-solids deliveries to streams and the remaining 56% of the deliveries came from the release of solutes through irrigation of cultivated and pasture lands, which comprise only 2.5% of the land area. Dissolved-solids accumulation is manifested as precipitated salts in the soil or underlying sediments, and (or) dissolved salts in soil-pore or sediment-pore water, or groundwater, and therefore represents a potential for aquifer contamination. Accumulation rates were <10,000(kg/year)/km2 for many hydrologic accounting units (large river basins), but were more than 40,000(kg/year)/km2 for the Middle Gila, Lower Gila-Agua Fria, Lower Gila, Lower Bear, Great Salt Lake accounting units, and 247,000(kg/year)/km2 for the Salton Sea accounting unit. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  18. Partition and size distribution of heavy metals in the flue gas from municipal solid waste incinerators in Taiwan.

    PubMed

    Yuan, Chung-Shin; Lin, Hsun-Yu; Wu, Chun-Hsin; Liu, Ming-Han

    2005-03-01

    This study investigates the partition of heavy metals in both solid and gas phases in the flue gas from municipal solid waste (MSW) incinerators. Six MSW incinerators in Taiwan were examined and heavy metals in the flue gas at the inlets and outlets of air pollution control devices (APCDs) were analyzed. Heavy metals including Hg, Pb, Cd, Zn, Cu and Cr were sampled by USEPA Method 29 and further analyzed using inductively coupled plasma-mass spectroscopy (ICP-MS) and cold vapor atomic absorption spectrometry (CVAAS). Experimental results revealed that the removal efficiencies of the APCDs for the heavy metals Pb, Cd, Zn, Cu and Cr greatly exceeded 90%, but that of Hg did not. Two groups of heavy metals upstream of APCDs were observed. Pb, Cd, Zn, Cu and Cr were present mainly in the solid phase with a solid to gas ratio (S/G) of over 12.3. However, in most cases, mercury appeared mainly in the gas phase with an S/G ratio from 0.15 to 1.04, because it has a low boiling point. Additionally, treatment with the APCDs increased the S/G ratio of mercury because gaseous mercury could be removed by injecting powdered activated carbon (PAC) into the flue gas. Moreover, the distribution of particle sizes in the solid phase was bimodal. Finer particles (d(p)2.5 microm) contained more Cr and Hg.

  19. Difference in water accumulation patterns between solid and closed hollow obturators under a thermal cycle.

    PubMed

    Tsuboi, Akito; Sakurai, Takeshi; Watanabe, Makoto

    2012-09-01

    Water accumulation in the hollow space of a maxillary obturator is a continuing problem, and it is unclear whether the porosity of acrylic resin is involved in the mechanism. The purposes of the study were to evaluate the effect of a hollow space in the resin obturator on water sorption under a thermal cycle and to determine factors associated with water accumulation in the obturator. Twenty solid spheres (30-mm diameter) and 40 hemispheres (30-mm diameter, 1.5 mm thickness) were fabricated from heat-polymerized acrylic resin. Closed hollow specimens consisted of 2 hemispheres joined with autopolymerizing resin. Ten solid and 10 closed hollow specimens were immersed in distilled water, whereas the other specimens were stored at 100% relative humidity. Each specimen was thermocycled (5°C-37°C) with a dwell time of 12 hours and weighed every 12 hours for 180 days. Of the 20 closed hollow specimens, 16 showed no water accumulation (8 in distilled water, 8 at 100% humidity). The weight of these specimens became saturated by day 90, with increases from the initial weight of 1.41% at 5°C and 1.36% at 37°C. By day 180, the weights of the solid specimens had increased by 0.96% at 5°C and 0.94% at 37°C. Weight fluctuation associated with temperature was observed for both types of specimens and for all storage conditions. It is concluded that water accumulation inside a closed hollow obturator is not directly related to the water absorption properties of the acrylic resin but is related to thermal damage of the obturator.

  20. Accumulator

    NASA Technical Reports Server (NTRS)

    Fenwick, J. R.; Karigan, G. H. (Inventor)

    1977-01-01

    An accumulator particularly adapted for use in controlling the pressure of a stream of fluid in its liquid phase utilizing the fluid in its gaseous phase was designed. The accumulator is characterized by a shell defining a pressure chamber having an entry throat for a liquid and adapted to be connected in contiguous relation with a selected conduit having a stream of fluid flowing through the conduit in its liquid phase. A pressure and volume stabilization tube, including an array of pressure relief perforations is projected into the chamber with the perforations disposed adjacent to the entry throat for accommodating a discharge of the fluid in either gaseous or liquid phases, while a gas inlet and liquid to gas conversion system is provided, the chamber is connected with a source of the fluid for continuously pressuring the chamber for controlling the pressure of the stream of liquid.

  1. Partitioning and accumulation rates of polycyclic aromatic hydrocarbons into polydimethylsiloxane thin films and black worms from aqueous samples.

    PubMed

    Qin, Zhipei; Mok, Sandra; Ouyang, Gangfeng; Dixon, D George; Pawliszyn, Janusz

    2010-05-14

    Partition equilibriums and extraction rates of polycyclic aromatic hydrocarbons (PAHs) were examined for live biomonitoring with oligochaetes (black worms, Lumbriculus variegatus) and for high surface area chemical passive samplers constructed from polydimethylsiloxane thin film. The goals were to better understand the principles of bioconcentration by aquatic organisms and to aid in the design of a convenient and simple chemical monitoring tool to replace the use of live animals. The worms and films were exposed simultaneously to the contaminated water stream. In the initial extraction stage, similar extracted amount per surface area indicated that thin-film samplers could mimic the behavior of worms for passive sampling. Equilibrium was reached faster by the thin films than by the worms. A good linear relationship between the bioconcentration factors and the film-water partition coefficients of PAHs was found, which demonstrated the feasibility of thin-film sampler for determining the bioavailability of PAHs in water. Compared to the lengthy and inconvenient process of liquid-liquid extraction in worm treatment, thin-film technique simplifies the sample pretreatment procedure by integrating sampling and sample preparation.

  2. Solid partitioning and solid-liquid distribution of 210Po and 210Pb in marine anoxic sediments: roads of Cherbourg at the northwestern France.

    PubMed

    Connan, O; Boust, D; Billon, G; Solier, L; Rozet, M; Bouderbala, S

    2009-10-01

    A sequential extraction protocol has been used to determine the solid-phase partition of (210)Po and (210)Pb in anoxic marine sediment from the roads of Cherbourg (France) in the central English Channel. Measurements were also obtained in pore waters, in which (210)Po activities range between 1 and 20 mBq L(-1) and (210)Pb activities between 2.4 and 3.8 mBq L(-1), with highest activities in the topmost layer. These activities are higher than in seawater, suggesting that sediment act as a source of both (210)Po and (210)Pb for overlying water. The (210)Po profile in the pore waters is apparently correlated with those obtained for Fe, Mn and SO(4)(2)(-), suggesting an influence of early diagenetic processes on the (210)Po solid-liquid distribution. In the sediment, (210)Po is predominantly bound to organic matter or chromium reducible sulphides, and residuals (clay minerals and refractory oxides). Our results indicate that (210)Po is not significantly bound to AVS, i.e. acid volatile sulphides: bioturbation could play a role by the early redistribution of (210)Po bound to acid volatile sulphides in the sediment. (210)Po, (210)Pb and Pb exhibit differences in terms of distribution, probably due to a different mode of penetration in the sediment. This work provides information on solid and liquid distribution of (210)Po and (210)Pb in marine sediment. These data are very scarce in the literature.

  3. Sugar loss and enzyme inhibition due to oligosaccharide accumulation during high solids-loading enzymatic hydrolysis

    DOE PAGES

    Xue, Saisi; Uppugundla, Nirmal; Bowman, Michael J.; ...

    2015-11-26

    Accumulation of recalcitrant oligosaccharides during high-solids loading enzymatic hydrolysis of cellulosic biomass reduces biofuel yields and increases processing costs for a cellulosic biorefinery. Recalcitrant oligosaccharides in AFEX-pretreated corn stover hydrolysate accumulate to the extent of about 18–25 % of the total soluble sugars in the hydrolysate and 12–18 % of the total polysaccharides in the inlet biomass (untreated), equivalent to a yield loss of about 7–9 kg of monomeric sugars per 100 kg of inlet dry biomass (untreated). These oligosaccharides represent a yield loss and also inhibit commercial hydrolytic enzymes, with both being serious bottlenecks for economical biofuel production frommore » cellulosic biomass. Very little is understood about the nature of these oligomers and why they are recalcitrant to commercial enzymes. This work presents a robust method for separating recalcitrant oligosaccharides from high solid loading hydrolysate in gramme quantities. Composition analysis, recalcitrance study and enzyme inhibition study were performed to understand their chemical nature. Results indicate that, oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, and ammonia fibre expansion: AFEX). The methodology for large-scale separation of recalcitrant oligosaccharides from 25 % solids-loading AFEXcorn stover hydrolysate using charcoal fractionation and size exclusion chromatography is reported for the first time. Oligosaccharides with higher degree of polymerization (DP) were recalcitrant towards commercial enzyme mixtures [Ctec2, Htec2 and Multifect pectinase (MP)] compared to lower DP oligosaccharides. Enzyme inhibition studies using processed substrates (Avicel and xylan) showed that low DP oligosaccharides also inhibit commercial enzymes. Addition of monomeric sugars to oligosaccharides increases the

  4. Sugar loss and enzyme inhibition due to oligosaccharide accumulation during high solids-loading enzymatic hydrolysis

    SciTech Connect

    Xue, Saisi; Uppugundla, Nirmal; Bowman, Michael J.; Cavalier, David; Da Costa Sousa, Leonardo; Dale, Bruce E.; Balan, Venkatesh

    2015-11-26

    Accumulation of recalcitrant oligosaccharides during high-solids loading enzymatic hydrolysis of cellulosic biomass reduces biofuel yields and increases processing costs for a cellulosic biorefinery. Recalcitrant oligosaccharides in AFEX-pretreated corn stover hydrolysate accumulate to the extent of about 18–25 % of the total soluble sugars in the hydrolysate and 12–18 % of the total polysaccharides in the inlet biomass (untreated), equivalent to a yield loss of about 7–9 kg of monomeric sugars per 100 kg of inlet dry biomass (untreated). These oligosaccharides represent a yield loss and also inhibit commercial hydrolytic enzymes, with both being serious bottlenecks for economical biofuel production from cellulosic biomass. Very little is understood about the nature of these oligomers and why they are recalcitrant to commercial enzymes. This work presents a robust method for separating recalcitrant oligosaccharides from high solid loading hydrolysate in gramme quantities. Composition analysis, recalcitrance study and enzyme inhibition study were performed to understand their chemical nature. Results indicate that, oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, and ammonia fibre expansion: AFEX). The methodology for large-scale separation of recalcitrant oligosaccharides from 25 % solids-loading AFEXcorn stover hydrolysate using charcoal fractionation and size exclusion chromatography is reported for the first time. Oligosaccharides with higher degree of polymerization (DP) were recalcitrant towards commercial enzyme mixtures [Ctec2, Htec2 and Multifect pectinase (MP)] compared to lower DP oligosaccharides. Enzyme inhibition studies using processed substrates (Avicel and xylan) showed that low DP oligosaccharides also inhibit commercial enzymes. Addition of monomeric sugars to oligosaccharides increases the

  5. Solid-liquid two-phase partitioning bioreactors (TPPBs) operated with waste polymers. Case study: 2,4-dichlorophenol biodegradation with used automobile tires as the partitioning phase.

    PubMed

    Tomei, M Concetta; Annesini, M Cristina; Daugulis, Andrew J

    2012-11-01

    Used automobile tire pieces were tested for their suitability as the sequestering phase in a two-phase partitioning bioreactor to treat 2,4-dichlorophenol (DCP). Abiotic sorption tests and equilibrium partitioning tests confirmed that tire "crumble" possesses very favourable properties for this application with DCP diffusivity (4.8 × 10(-8) cm(2)/s) and partition coefficient (31) values comparable to those of commercially available polymers. Biodegradation tests further validated the effectiveness of using waste tires to detoxify a DCP solution, and allow for enhanced biodegradation compared to conventional single-phase operation. These results establish the potential of using a low-cost waste material to assist in the bioremediation of a toxic aqueous contaminant.

  6. Nonlinear Stability of Convection in a Porous Layer with Solid Partitions

    NASA Astrophysics Data System (ADS)

    Straughan, B.

    2014-07-01

    We show that for many classes of convection problem involving a porous layer, or layers, interleaved with finite but non-deformable solid layers, the global nonlinear stability threshold is exactly the same as the linear instability one. The layer(s) of porous material may be of Darcy type, Brinkman type, possess an anisotropic permeability, or even be such that they are of local thermal non-equilibrium type where the fluid and solid matrix constituting the porous material may have different temperatures. The key to the global stability result lies in proving the linear operator attached to the convection problem is a symmetric operator while the nonlinear terms must satisfy appropriate conditions.

  7. The impact of EDTA on the rate of accumulation and root/shoot partitioning of cadmium in mature dwarf sunflowers.

    PubMed

    Meighan, Michelle M; Fenus, Taressa; Karey, Emma; MacNeil, Joseph

    2011-06-01

    In addition to increasing the mobility of metal ions in the soil solution, chelating agents such as EDTA have been reported to alter both the total metal accumulated by plants and its distribution within the plant structures. Here, mature Mini-Sun Hybrid dwarf sunflowers exposed to 300 μM Cd(2+) in hydroponic solution had initial translocation rates of at least 0.12 mmol kg(-1)h(-1) and reached leaf saturation levels within a day when a 3-fold molar excess of EDTA was used. EDTA also promoted cadmium transfer from roots to the shoots. A threefold excess of EDTA increased the translocation factor (TF) 100-fold, resulting in cadmium levels in the leaves of 580 μg g(-1) and extracting 1400 μg plant(-1). When plants were exposed to dissolved cadmium without EDTA, the vast majority of the metal remained bound to the exterior of the root. The initial accumulation could be successfully modeled with a standard biosorption pseudo second-order kinetic equation. Initial accumulation rates ranged from 0.0359 to 0.262 mg g(-1)min(-1). The cadmium binding could be cycled, and did not show evidence of saturation under the experimental conditions employed, suggesting it might be a viable biosorbant for aqueous cadmium.

  8. Partitioned fluid-solid coupling for cardiovascular blood flow: left-ventricular fluid mechanics.

    PubMed

    Krittian, Sebastian; Janoske, Uwe; Oertel, Herbert; Böhlke, Thomas

    2010-04-01

    We present a 3D code-coupling approach which has been specialized towards cardiovascular blood flow. For the first time, the prescribed geometry movement of the cardiovascular flow model KaHMo (Karlsruhe Heart Model) has been replaced by a myocardial composite model. Deformation is driven by fluid forces and myocardial response, i.e., both its contractile and constitutive behavior. Whereas the arbitrary Lagrangian-Eulerian formulation (ALE) of the Navier-Stokes equations is discretized by finite volumes (FVM), the solid mechanical finite elasticity equations are discretized by a finite element (FEM) approach. Taking advantage of specialized numerical solution strategies for non-matching fluid and solid domain meshes, an iterative data-exchange guarantees the interface equilibrium of the underlying governing equations. The focus of this work is on left-ventricular fluid-structure interaction based on patient-specific magnetic resonance imaging datasets. Multi-physical phenomena are described by temporal visualization and characteristic FSI numbers. The results gained show flow patterns that are in good agreement with previous observations. A deeper understanding of cavity deformation, blood flow, and their vital interaction can help to improve surgical treatment and clinical therapy planning.

  9. Using solid-phase microextraction to determine partition coefficients to humic acids and bioavailable concentrations of hydrophobic chemicals

    SciTech Connect

    Ramos, E.U.; Meijer, S.N.; Vaes, W.H.J.; Verhaar, H.J.M.; Hermens, J.L.M.

    1998-11-01

    In the current study, the suitability of negligible depletion solid-phase microextraction (nd-SPME) to determine free fractions of chemicals in aquatic environments was explored. The potential interferences of the dissolved matrix (i.e., humic acids) with the SPME measurements were tested. Results show that nd-SPME measures only the freely dissolved fraction and that the measurements are not disturbed by the humic acids. In addition, nd-SPME was used to determine partition coefficients between dissolved organic carbon and water for four hydrophobic chemicals. Obtained values are in excellent agreement with previously reported data. Finally, the bioaccumulation of hexachlorobenzene and PCB 77 to Daphnia magna was determined in the presence and absence of humic acids. The bioconcentration factors (BCF) were calculated based on total as well as on free concentration. Lower BCF values are obtained in the presence of humic acids using total concentrations, whereas equal BCFs are found using free concentrations measured with nd-SPME. Therefore, the authors can conclude that negligible depletion SPME is a good technique to determine bioavailable concentrations of hydrophobic chemicals in aquatic environments.

  10. Understanding the accumulation of P-glycoprotein substrates within cells: The effect of cholesterol on membrane partitioning.

    PubMed

    Subramanian, Nandhitha; Schumann-Gillett, Alexandra; Mark, Alan E; O'Mara, Megan L

    2016-04-01

    The apparent activity of the multidrug transporter P-glycoprotein (P-gp) is enhanced by the presence of cholesterol. Whether this is due to the direct effect of cholesterol on the activity of P-gp, its effect on the local concentration of substrate in the membrane, or its effect on the rate of entry of the drug into the cell, is unknown. In this study, molecular dynamics simulation techniques coupled with potential of mean force calculations have been used to investigate the role of cholesterol in the movement of four P-gp substrates across a POPC bilayer in the presence or absence of 10% cholesterol. The simulations suggest that the presence of cholesterol lowers the free energy associated with entering the middle of the bilayer in a substrate-specific manner. These findings suggest that P-gp substrates may preferentially accumulate in cholesterol-rich regions of the membrane, which may explain its enhanced transport activity.

  11. Cobalt and nickel uptake by rice and accumulation in soil amended with municipal solid waste compost.

    PubMed

    Bhattacharyya, P; Chakrabarti, K; Chakraborty, A; Tripathy, S; Kim, K; Powell, M A

    2008-03-01

    Effect of addition of municipal solid waste compost (MSWC) on cobalt (Co) and nickel (Ni) contents of submerged rice paddies were studied. A sequential extraction method was used to determine the metal (Co and Ni) fractions in MSWC and cow dung manure (CDM). Both metals were significantly bound to the organic matter and Fe and Mn oxides in MSWC and CDM. Metal content in rice straw was higher than in rice grain. Metal bound with Fe and Mn oxides in MSWC and CDM best correlated with straw and grain metal followed by water soluble and exchangeable fractions. Carbonate, organic matter bound and residual fractions in MSWC and CDM did not significantly correlate with rice straw and grain metal. MSWC would be a valuable resource for agriculture, but long-term field experiments with MSWC are needed to assess by regular monitoring of the metal loads and accumulation in soil and plants.

  12. Overexpression of the transporters AtZIP1 and AtMTP1 in cassava changes zinc accumulation and partitioning

    PubMed Central

    Gaitán-Solís, Eliana; Taylor, Nigel J.; Siritunga, Dimuth; Stevens, William; Schachtman, Daniel P.

    2015-01-01

    Zinc deficiency in humans is a serious problem worldwide with an estimated one third of populations at risk for insufficient zinc in diet, which leads to impairment of cognitive abilities and immune system function. The goal of this research was to increase the bioavailable zinc in the edible portion of cassava roots to improve the overall zinc nutrition of populations that rely on cassava as a dietary staple. To increase zinc concentrations, two Arabidopsis thaliana genes coding for ZIP1 and MTP1 were overexpressed with a tuber-specific or constitutive promoter. Eighteen transgenic events from four constructs, out of a total of 73 events generated, showed significantly higher zinc concentrations in the edible portion of the storage root compared to the non-transgenic controls. The zinc content in the transgenic lines ranged from 4 to 73 mg/kg dry weight (DW) as compared to the non-transgenic control which contained 8 mg/kg. Striking changes in whole plant phenotype such as smaller plant size and chlorotic leaves were observed in transgenic lines that over accumulated zinc. In a confined field trial five transgenic events grown for 12 months showed a range of zinc concentrations from 18 to 217 mg/kg DW. Although the overexpression of zinc transporters was successful in increasing the zinc concentrations in 25% of the transgenic lines generated, it also resulted in a decrease in plant and tuber size and overall yield due to what appears to be zinc deficiency in the aerial parts of the plant. PMID:26217349

  13. The Influence of Precipitation Regimes and Elevated CO2 on Photosynthesis and Biomass Accumulation and Partitioning in Seedlings of the Rhizomatous Perennial Grass Leymus chinensis

    PubMed Central

    Li, Zhuolin; Zhang, Yuting; Yu, Dafu; Zhang, Na; Lin, Jixiang; Zhang, Jinwei; Tang, Jiahong; Wang, Junfeng; Mu, Chunsheng

    2014-01-01

    Leymus chinensis is a dominant, rhizomatous perennial C3 species in the grasslands of Songnen Plain of Northern China, and its productivity has decreased year by year. To determine how productivity of this species responds to different precipitation regimes, elevated CO2 and their interaction in future, we measured photosynthetic parameters, along with the accumulation and partitioning of biomass. Plants were subjected to combinations of three precipitation gradients (normal precipitation, versus normal ± 40%) and two CO2 levels (380±20 µmol mol-1,760±20 µmol mol-1) in controlled-environment chambers. The net photosynthetic rate, and above-ground and total biomass increased due to both elevated CO2 and increasing precipitation, but not significantly so when precipitation increased from the normal to high level under CO2 enrichment. Water use efficiency and the ratio of root: total biomass increased significantly when precipitation was low, but decreased when it was high under CO2 enrichment. Moreover, high precipitation at the elevated level of CO2 increased the ratio between stem biomass and total biomass. The effect of elevated CO2 on photosynthesis and biomass accumulation was higher at the low level of precipitation than with normal or high precipitation. The results suggest that at ambient CO2 levels, the net photosynthetic rate and biomass of L. chinensis increase with precipitation, but those measures are not further affected by additional precipitation when CO2 is elevated. Furthermore, CO2 may partly compensate for the negative effect of low precipitation on the growth and development of L. chinensis. PMID:25093814

  14. The Partition Intervalometer: A Programmable Underwater Timer for Marking Accumulated Sediment Profiles Collected in Anderson Sediment Traps: Development, Operation, Testing Procedures, and Field Results

    USGS Publications Warehouse

    Rendigs, Richard R.; Anderson, Roger Y.; Xu, Jingping; Davis, Raymond E.; Bergeron, Emile M.

    2009-01-01

    This manual illustrates the development of a programmable instrument designed to deploy a series of wafer-shaped discs (partitions) into the collection tube of a sediment trap in various aquatic environments. These hydrodynamically shaped discs are deployed at discrete time intervals from the Intervalometer and provide markers that delineate time intervals within the sediments that accumulate in the collection tube. The timer and mechanical system are lodged in an air-filled, water-tight pressure housing that is vertically hung within the confines of a cone-shaped sediment trap. The instrumentation has been operationally pressure tested to an equivalent water depth of approximately 1 km. Flaws discovered during extensive laboratory and pressure testing resulted in the implementation of several mechanical modifications (such as a redesign of the rotor and the discs) that improved the operation of the rotor assembly as well as the release of discs through the end cap. These results also identified a preferred azimuth placement of the rotor disc relative to the drop hole of the end cap. In the initial field trial, five sediment traps and coupled Intervalometers were attached to moored arrays and deployed at two sites off the coast of Southern California for approximately 8 months. Each of the instruments released 18 discs at the programmed 10 day intervals, except one unit, which experienced a malfunction after approximately 4 months. Most of the discs oriented in a near-horizontal position upon the surface of the sediment in the collection tubes. Sampling of the sediments for geochemical analyses was improved by these clearly defined markers, which indicated the changes in the flux and nature of sediments accumulated during the deployment period of each sediment trap.

  15. Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition, chlorine content and temperature

    SciTech Connect

    Saqib, Naeem Bäckström, Mattias

    2014-12-15

    Highlights: • Different solids waste incineration is discussed in grate fired and fluidized bed boilers. • We explained waste composition, temperature and chlorine effects on metal partitioning. • Excessive chlorine content can change oxide to chloride equilibrium partitioning the trace elements in fly ash. • Volatility increases with temperature due to increase in vapor pressure of metals and compounds. • In Fluidized bed boiler, most metals find themselves in fly ash, especially for wood incineration. - Abstract: Trace element partitioning in solid waste (household waste, industrial waste, waste wood chips and waste mixtures) incineration residues was investigated. Samples of fly ash and bottom ash were collected from six incineration facilities across Sweden including two grate fired and four fluidized bed incinerators, to have a variation in the input fuel composition (from pure biofuel to mixture of waste) and different temperature boiler conditions. As trace element concentrations in the input waste at the same facilities have already been analyzed, the present study focuses on the concentration of trace elements in the waste fuel, their distribution in the incineration residues with respect to chlorine content of waste and combustion temperature. Results indicate that Zn, Cu and Pb are dominating trace elements in the waste fuel. Highly volatile elements mercury and cadmium are mainly found in fly ash in all cases; 2/3 of lead also end up in fly ash while Zn, As and Sb show a large variation in distribution with most of them residing in the fly ash. Lithophilic elements such as copper and chromium are mainly found in bottom ash from grate fired facilities while partition mostly into fly ash from fluidized bed incinerators, especially for plants fuelled by waste wood or ordinary wood chips. There is no specific correlation between input concentration of an element in the waste fuel and fraction partitioned to fly ash. Temperature and chlorine

  16. Carbon, Nitrogen and Phosphorus Accumulation and Partitioning, and C:N:P Stoichiometry in Late-Season Rice under Different Water and Nitrogen Managements

    PubMed Central

    Ye, Yushi; Liang, Xinqiang; Chen, Yingxu; Li, Liang; Ji, Yuanjing; Zhu, Chunyan

    2014-01-01

    Water and nitrogen availability plays an important role in the biogeochemical cycles of essential elements, such as carbon (C), nitrogen (N) and phosphorus (P), in agricultural ecosystems. In this study, we investigated the seasonal changes of C, N and P concentrations, accumulation, partitioning, and C:N:P stoichiometric ratios in different plant tissues (root, stem-leaf, and panicle) of late-season rice under two irrigation regimes (continuous flooding, CF; alternate wetting and drying, AWD) and four N managements (control, N0; conventional urea at 240 kg N ha−1, UREA; controlled-release bulk blending fertilizer at 240 kg N ha−1, BBF; polymer-coated urea at 240 kg N ha−1, PCU). We found that water and N treatments had remarkable effects on the measured parameters in different plant tissues after transplanting, but the water and N interactions had insignificant effects. Tissue C:N, N:P and C:P ratios ranged from 14.6 to 52.1, 3.1 to 7.8, and 76.9 to 254.3 over the rice growing seasons, respectively. The root and stem-leaf C:N:P and panicle C:N ratios showed overall uptrends with a peak at harvest whereas the panicle N:P and C:P ratios decreased from filling to harvest. The AWD treatment did not affect the concentrations and accumulation of tissue C and N, but greatly decreased those of P, resulting in enhanced N:P and C:P ratios. N fertilization significantly increased tissue N concentration, slightly enhanced tissue P concentration, but did not affect tissue C concentration, leading to a significant increase in tissue N:P ratio but a decrease in C:N and C:P ratios. Our results suggested that the growth of rice in the Taihu Lake region was co-limited by N and P. These findings broadened our understanding of the responses of plant C:N:P stoichiometry to simultaneous water and N managements in subtropical high-yielding rice systems. PMID:24992006

  17. Carbon, nitrogen and phosphorus accumulation and partitioning, and C:N:P stoichiometry in late-season rice under different water and nitrogen managements.

    PubMed

    Ye, Yushi; Liang, Xinqiang; Chen, Yingxu; Li, Liang; Ji, Yuanjing; Zhu, Chunyan

    2014-01-01

    Water and nitrogen availability plays an important role in the biogeochemical cycles of essential elements, such as carbon (C), nitrogen (N) and phosphorus (P), in agricultural ecosystems. In this study, we investigated the seasonal changes of C, N and P concentrations, accumulation, partitioning, and C:N:P stoichiometric ratios in different plant tissues (root, stem-leaf, and panicle) of late-season rice under two irrigation regimes (continuous flooding, CF; alternate wetting and drying, AWD) and four N managements (control, N0; conventional urea at 240 kg N ha(-1), UREA; controlled-release bulk blending fertilizer at 240 kg N ha(-1), BBF; polymer-coated urea at 240 kg N ha(-1), PCU). We found that water and N treatments had remarkable effects on the measured parameters in different plant tissues after transplanting, but the water and N interactions had insignificant effects. Tissue C:N, N:P and C:P ratios ranged from 14.6 to 52.1, 3.1 to 7.8, and 76.9 to 254.3 over the rice growing seasons, respectively. The root and stem-leaf C:N:P and panicle C:N ratios showed overall uptrends with a peak at harvest whereas the panicle N:P and C:P ratios decreased from filling to harvest. The AWD treatment did not affect the concentrations and accumulation of tissue C and N, but greatly decreased those of P, resulting in enhanced N:P and C:P ratios. N fertilization significantly increased tissue N concentration, slightly enhanced tissue P concentration, but did not affect tissue C concentration, leading to a significant increase in tissue N:P ratio but a decrease in C:N and C:P ratios. Our results suggested that the growth of rice in the Taihu Lake region was co-limited by N and P. These findings broadened our understanding of the responses of plant C:N:P stoichiometry to simultaneous water and N managements in subtropical high-yielding rice systems.

  18. Transfers of iodine in the soil-plant-air system: Solid-liquid partitioning, migration, plant uptake adn volatilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Human exposure to soil iodine depends upon the partitioning of the iodine into the, mobile, liquid and gaseous soil phases. From the liquid phase, iodine can be transported into surface- and ground-waters, plant roots, and, consequently, into the human diet. From the gaseous phase, iodine can be tra...

  19. Trace element partitioning in ashes from boilers firing pure wood or mixtures of solid waste with respect to fuel composition, chlorine content and temperature.

    PubMed

    Saqib, Naeem; Bäckström, Mattias

    2014-12-01

    Trace element partitioning in solid waste (household waste, industrial waste, waste wood chips and waste mixtures) incineration residues was investigated. Samples of fly ash and bottom ash were collected from six incineration facilities across Sweden including two grate fired and four fluidized bed incinerators, to have a variation in the input fuel composition (from pure biofuel to mixture of waste) and different temperature boiler conditions. As trace element concentrations in the input waste at the same facilities have already been analyzed, the present study focuses on the concentration of trace elements in the waste fuel, their distribution in the incineration residues with respect to chlorine content of waste and combustion temperature. Results indicate that Zn, Cu and Pb are dominating trace elements in the waste fuel. Highly volatile elements mercury and cadmium are mainly found in fly ash in all cases; 2/3 of lead also end up in fly ash while Zn, As and Sb show a large variation in distribution with most of them residing in the fly ash. Lithophilic elements such as copper and chromium are mainly found in bottom ash from grate fired facilities while partition mostly into fly ash from fluidized bed incinerators, especially for plants fuelled by waste wood or ordinary wood chips. There is no specific correlation between input concentration of an element in the waste fuel and fraction partitioned to fly ash. Temperature and chlorine content have significant effects on partitioning characteristics by increasing the formation and vaporization of highly volatile metal chlorides. Zinc and cadmium concentrations in fly ash increase with the incineration temperature.

  20. Modeled Sources, Transport, and Accumulation of Dissolved Solids in Water Resources of the Southwestern United States1

    PubMed Central

    Anning, David W

    2011-01-01

    Abstract Information on important source areas for dissolved solids in streams of the southwestern United States, the relative share of deliveries of dissolved solids to streams from natural and human sources, and the potential for salt accumulation in soil or groundwater was developed using a SPAtially Referenced Regressions On Watershed attributes model. Predicted area-normalized reach-catchment delivery rates of dissolved solids to streams ranged from <10 (kg/year)/km2 for catchments with little or no natural or human-related solute sources in them to 563,000 (kg/year)/km2 for catchments that were almost entirely cultivated land. For the region as a whole, geologic units contributed 44% of the dissolved-solids deliveries to streams and the remaining 56% of the deliveries came from the release of solutes through irrigation of cultivated and pasture lands, which comprise only 2.5% of the land area. Dissolved-solids accumulation is manifested as precipitated salts in the soil or underlying sediments, and (or) dissolved salts in soil-pore or sediment-pore water, or groundwater, and therefore represents a potential for aquifer contamination. Accumulation rates were <10,000 (kg/year)/km2 for many hydrologic accounting units (large river basins), but were more than 40,000 (kg/year)/km2 for the Middle Gila, Lower Gila-Agua Fria, Lower Gila, Lower Bear, Great Salt Lake accounting units, and 247,000 (kg/year)/km2 for the Salton Sea accounting unit. PMID:22457583

  1. A comparative study of solid and liquid non-aqueous phases for the biodegradation of hexane in two-phase partitioning bioreactors.

    PubMed

    Hernández, María; Quijano, Guillermo; Thalasso, Frédéric; Daugulis, Andrew J; Villaverde, Santiago; Muñoz, Raúl

    2010-08-01

    A comparative study of the performance of solid and liquid non-aqueous phases (NAPs) to enhance the mass transfer and biodegradation of hexane by Pseudomonas aeruginosa in two-phase partitioning bioreactors (TPPBs) was undertaken. A preliminary NAP screening was thus carried out among the most common solid and liquid NAPs used in pollutant biodegradation. The polymer Kraton G1657 (solid) and the liquid silicone oils SO20 and SO200 were selected from this screening based on their biocompatibility, resistance to microbial attack, non-volatility and high affinity for hexane (low partition coefficient: K = C(g)/C(NAP), where C(g) and C(NAP) represent the pollutant concentration in the gas phase and NAP, respectively). Despite the three NAPs exhibited a similar affinity for hexane (K approximately 0.0058), SO200 and SO20 showed a superior performance to Kraton G1657 in terms of hexane mass transfer and biodegradation enhancement. The enhanced performance of SO200 and SO20 could be explained by both the low interfacial area of this solid polymer (as a result of the large size of commercial beads) and by the interference of water on hexane transfer (observed in this work). When Kraton G1657 (20%) was tested in a TPPB inoculated with P. aeruginosa, steady state elimination capacities (ECs) of 5.6 +/- 0.6 g m(-3) h(-1) were achieved. These values were similar to those obtained in the absence of a NAP but lower compared to the ECs recorded in the presence of 20% of SO200 (10.6 +/- 0.9 g m(-3) h(-1)). Finally, this study showed that the enhancement in the transfer of hexane supported by SO200 was attenuated by limitations in microbial activity, as shown by the fact that the ECs in biotic systems were far lower than the maximum hexane transfer capacity recorded under abiotic conditions.

  2. Bisphenol A in Solid Waste Materials, Leachate Water, and Air Particles from Norwegian Waste-Handling Facilities: Presence and Partitioning Behavior.

    PubMed

    Morin, Nicolas; Arp, Hans Peter H; Hale, Sarah E

    2015-07-07

    The plastic additive bisphenol A (BPA) is commonly found in landfill leachate at levels exceeding acute toxicity benchmarks. To gain insight into the mechanisms controlling BPA emissions from waste and waste-handling facilities, a comprehensive field and laboratory campaign was conducted to quantify BPA in solid waste materials (glass, combustibles, vehicle fluff, waste electric and electronic equipment (WEEE), plastics, fly ash, bottom ash, and digestate), leachate water, and atmospheric dust from Norwegian sorting, incineration, and landfill facilities. Solid waste concentrations varied from below 0.002 mg/kg (fly ash) to 188 ± 125 mg/kg (plastics). A novel passive sampling method was developed to, for the first time, establish a set of waste-water partition coefficients, KD,waste, for BPA, and to quantify differences between total and freely dissolved concentrations in waste-facility leachate. Log-normalized KD,waste (L/kg) values were similar for all solid waste materials (from 2.4 to 3.1), excluding glass and metals, indicating BPA is readily leachable. Leachate concentrations were similar for landfills and WEEE/vehicle sorting facilities (from 0.7 to 200 μg/L) and dominated by the freely dissolved fraction, not bound to (plastic) colloids (agreeing with measured KD,waste values). Dust concentrations ranged from 2.3 to 50.7 mg/kgdust. Incineration appears to be an effective way to reduce BPA concentrations in solid waste, dust, and leachate.

  3. Melting and solid-melt partitioning in iron-light element systems under megabar conditions: Implications for the thermal state of the Core

    NASA Astrophysics Data System (ADS)

    Ohtani, E.; Kamada, S.; Sakai, T.; Terasaki, H.; Hayashi, H.

    2011-12-01

    The experimental study of the core was pioneered by H.K. Mao [1]. After his pioneering works, significant developments have been made in our high pressure science community to clarify the Earth's core. We have extended the pressure range of melting experiments of iron-light element compounds to pressures exceeding 100 GPa. Melting can be detected by using different criteria, i.e., a change of laser heating efficiency, in situ X-ray diffraction, and the textural change of the recovered samples after quenching from melts. These criteria are generally consistent with one another and enabled us to constrain the temperature, thermal state, and the composition of the core. Melting and phase relations of the Fe-Si, Fe-S, Fe-Ni-S and Fe-S-O systems were determined up to the core pressures based on the in situ X-ray diffraction and a change of laser heating efficiency and texture of the recovered samples by the laser heated diamond anvil cell [2,3,4]. The melting curves may provide constraints for temperatures at the core-mantle boundary (CMB) and the inner core boundary (ICB). Melting and phase relations of the Fe-Fe3S and Fe-S-O systems revealed that Fe3S dissolves first at the solidus before melting of the metallic iron alloy at the liquidus at least up to 180 GPa. The (FeNi)3S phase together with hcp-FeNi is stable up to the pressure above 200 GPa. Therefore, these phases are candidates for the constituent of the inner core. Solid-liquid partitioning experiments can be made by the laser heated diamond anvil cell. The partitioning experiment of Pt, Re, and Os between solid hcp-FeNi alloy and Fe-Ni-S liquid metals is an example of such experiments. It has been assumed that Os isotopic signatures showing coupled 186Os/188Os and 187Os/188Os enrichments in some plume magmas is originated from contamination of outer core materials formed by the inner core fractionation at the base of the lower mantle [5]. We conducted partitioning experiments of Pt, Re, and Os up to 100 GPa

  4. Partitioning of platinum-group elements (PGE) and chalcogens (Se, Te, As, Sb, Bi) between monosulfide-solid solution (MSS), intermediate solid solution (ISS) and sulfide liquid at controlled fO2-fS2 conditions

    NASA Astrophysics Data System (ADS)

    Liu, Yanan; Brenan, James

    2015-06-01

    In order to better understand the behavior of highly siderophile elements (HSEs: Os, Ir, Ru, Rh, Pt, Pd, Au, Re), Ag, Pb and chalcogens (As, Se, Sb, Te and Bi) during the solidification of sulfide magmas, we have conducted a series of experiments to measure partition coefficients (D values) between monosulfide solid solution (MSS) and sulfide melt, as well as MSS and intermediate solid solution (ISS), at 0.1 MPa and 860-926 °C, log fS2 -3.0 to -2.2 (similar to the Pt-PtS buffer), with fO2 controlled at the fayalite-magnetite-quartz (FMQ) buffer. The IPGEs (Os, Ir, Ru), Rh and Re are found to be compatible in MSS relative to sulfide melt with D values ranging from ∼20 to ∼5, and DRe/DOs of ∼0.5. Pd, Pt, Au, Ag, Pb, as well as the chalcogens, are incompatible in MSS, with D values ranging from ∼0.1 to ∼1 × 10-3. For the same metal/sulfur ratio, D values for the IPGEs, Rh and Re are systematically larger than most past studies, correlating with higher oxygen content in the sulfide liquid, reflecting the significant effect of oxygen on increasing the activity coefficients for these elements in the melt phase. MSS/ISS partitioning experiments reveal that Ru, Os, Ir, Rh and Re are partitioned into MSS by a factor of >50, whereas Pd, Pt, Ag, Au and the chalcogens partition from weakly (Se, As) to strongly (Ag, Au) into ISS. Uniformly low MSS- and ISS- melt partition coefficients for the chalcogens, Pt, Pd, Ag and Au will lead to enrichment in the residual sulfide liquid, but D values are generally too large to reach early saturation in Pt-Pd-chalcogen-rich accessory minerals, based on current solubility estimates. Instead, these phases likely precipitate at the last dregs of crystallization. Modeled evolution curves for the PGEs and chalcogens are in reasonably good agreement with whole-rock sulfide compositions for the McCreedy East deposit (Sudbury, Ontario), consistent with an origin by crystallization of MSS, then MSS + ISS from sulfide magma.

  5. Study of the separation limits of continuous solid support free liquid-liquid chromatography: separation of capsaicin and dihydrocapsaicin by centrifugal partition chromatography.

    PubMed

    Goll, Johannes; Frey, Andreas; Minceva, Mirjana

    2013-04-05

    Sequential centrifugal partition chromatography (sCPC) is a cyclic solid support-free liquid-liquid chromatographic process, in which a continuously introduced feed mixture is separated into two sequentially collected product streams. The few experimental demonstrations of this concept already revealed its potential for the preparative separation of pharmaceuticals and fine chemicals. In this work not only the possibilities, but also the limits of the sCPC technology are explored. A feed mixture consisting of capsaicin and dihydrocapsaicin, whose molecular structure differs in only one double bond, was selected for this purpose. The sCPC unit operating parameters needed for a complete separation of the feed mixture were selected using the recently published approach, which uses the partition coefficient of the feed components and the hydrodynamic characteristics of the system as input data. A complete separation of capsaicin and dihydrocapsaicin with the solvent system heptane/ethyl acetate/methanol/water:1/1/1/1 (v/v/v/v) was achieved, although the separation factor was only 1.32. The sCPC unit separation performance was successfully simulated using the cell model.

  6. Effect of corn preparation methods on dry-grind ethanol production by granular starch hydrolysis and partitioning of spent beer solids.

    PubMed

    Lamsal, B P; Wang, H; Johnson, L A

    2011-06-01

    Two corn preparation methods, rollermill flaking and hammermill grinding, were compared for efficient processing of corn into ethanol by granular starch hydrolysis and simultaneous fermentation by yeast Saccharomyces cerevisiae. Corn was either ground in a hammermill with different size screens or crushed in a smooth-surfaced rollermill at different roller gap settings. The partitioning of beer solids and size distribution of solids in the thin stillage were compared. The mean particle diameter d(50) for preparations varied with set-ups and ranged between 210 and 340 μm for ground corn, and 1180-1267 μm for flaked corn. The ethanol concentrations in beer were similar (18-19% v/v) for ground and flaked preparations, however, ethanol productivity increased with reduced particle size. Roller versus hammermilling of corn reduced solids in thin stillage by 28%, and doubled the volume percent of fines (d(50) ∼ 7 μm)in thin stillage and decreased coarse (d(50) ∼ 122 μm) by half compared to hammermilling.

  7. [A Simultaneous Determination Method with Acetonitrile-n-Hexane Partitioning and Solid-Phase Extraction for Pesticide Residues in Livestock and Marine Products by GC-MS].

    PubMed

    Yoshizaki, Mayuko; Kobayashi, Yukari; Shimizu, Masanori; Maruyama, Kouichi

    2015-01-01

    A simultaneous determination method was examined for 312 pesticides (including isomers) in muscle of livestock and marine products by GC-MS. The pesticide residues extracted from samples with acetone and n-hexane were purified by acetonitrile-n-hexane partitioning, and C18 and SAX/PSA solid-phase extraction without using GPC. Matrix components such as cholesterol were effectively removed. In recovery tests performed by this method using pork, beef, chicken and shrimp, 237-257 pesticides showed recoveries within the range of 70-120% in each sample. Validity was confirmed for 214 of the target pesticides by means of a validation test using pork. In comparison with the Japanese official method using GPC, the treatment time of samples and the quantity of solvent were reduced substantially.

  8. Partitioning of rhodium and ruthenium between Pd-Rh-Ru and (Ru,Rh)O2 solid solutions in high-level radioactive waste glass

    NASA Astrophysics Data System (ADS)

    Sugawara, Toru; Ohira, Toshiaki; Komamine, Satoshi; Ochi, Eiji

    2015-10-01

    The partitioning of rhodium and ruthenium between Pd-Rh-Ru alloy with a face-centered cubic (FCC) structure and (Ru,Rh)O2 solid solution has been investigated between 1273 and 1573 K at atmospheric oxygen fugacity. The rhodium and ruthenium contents in FCC increase, while the RhO2 content in (Ru,Rh)O2 decreases with increasing temperature due to progressive reduction of the system. Based on the experimental results and previously reported thermodynamic data, the thermodynamic mixing properties of FCC phase and (Ru,Rh)O2 have been calibrated in an internally consistent manner. Phase equilibrium of platinum grope metals in an HLW glass was calculated by using the obtained thermodynamic parameters.

  9. Improved reactor performance and operability in the biotransformation of carveol to carvone using a solid-liquid two-phase partitioning bioreactor.

    PubMed

    Morrish, Jenna L E; Daugulis, Andrew J

    2008-12-01

    In an effort to improve reactor performance and process operability, the microbial biotransformation of (-)-trans-carveol to (R)-(-)-carvone by hydrophobic Rhodococcus erythropolis DCL14 was carried out in a two phase partitioning bioreactor (TPPB) with solid polymer beads acting as the partitioning phase. Previous work had demonstrated that the substrate and product become inhibitory to the organism at elevated aqueous concentrations and the use of an immiscible second phase in the bioreactor was intended to provide a reservoir for substrates to be delivered to the aqueous phase based on the metabolic rate of the cells, while also acting as a sink to uptake the product as it is produced. The biotransformation was previously undertaken in a two liquid phase TPPB with 1-dodecene and with silicone oil as the immiscible second phase and, although improvement in the reactor performance was obtained relative to a single phase system, the hydrophobic nature of the organism caused the formation of severe emulsions leading to significant operational challenges. In the present work, eight types of polymer beads were screened for their suitability for use in a solid-liquid TPPB for this biotransformation. The use of selected solid polymer beads as the second phase completely prevented emulsion formation and therefore improved overall operability of the reactor. Three modes of solid-liquid TPPB operation were considered: the use of a single polymer bead type (styrene/butadiene copolymer) in the reactor, the use of a mixture of polymer beads in the reactor (styrene/butadiene copolymer plus Hytrel(R) 8206), and the use of one type of polymer beads in the reactor (styrene/butadiene copolymer), and another bead type (Hytrel(R) 8206) in an external column through which fermentation medium was recirculated. This last configuration achieved the best reactor performance with 7 times more substrate being added throughout the biotransformation relative to a single aqueous phase

  10. Solid / Liquid Partitioning of Iron in (Mg0.9Fe0.1)2SiO4 Bulk Composition under Lower Mantle Conditions

    NASA Astrophysics Data System (ADS)

    Nomura, R.; Hirose, K.; Tateno, S.

    2009-12-01

    Melting causes strong chemical differentiation in the Earth’s interior. It is generally believed that ultra-low velocity zone (ULVZ) observed in the lowermost mantle represents the partially molten zone, but the nature of partial melting is not known yet. Is the partial melt enriched in iron? Is it denser than coexisting solid? Here we investigate the partitioning of iron between partial melt and solid residue in (Mg0.9Fe0.1)2SiO4 bulk composition up to 61 GPa using laser-heated diamond-anvil cell (LHDAC). We used the olivine from KLB-1 peridotite as starting material and loaded its powder between the argon pressure medium. The sample was heated from double side using the Nd:YLF laser. Melting was confirmed by a sudden increase in the absorption of the laser light by the sample. A recovered sample was processed to a thin film by Ar ion using the Ion Slicer, and subsequently examined under field emission-type microprobe (FE-EPMA). The X-ray mapping of the sample showed the extensive segregation of each phase under the temperature gradient. The center of the laser-heated hot spot had non-stoichiometric composition, indicating a quenched liquid. Liquidus phase was found to be ferropericlase (Fp) up to ~26 GPa and changed into Mg-silicate perovskite (MgPv) at about 31GPa, consistent with the results obtained by previous melting experiments in multi-anvil apparatus (Ohtani et al., 1998 PEPI; Ito et al., 2004 PEPI). MgPv remains the liquidus phase up to 61 GPa, the highest pressure condition examined so far in this study. We determined the iron partitioning between MgPv and melt (D= FeO (in crystal, wt.%) / FeO (in liquid, wt.%)) from the results of chemical analyses. The partition coefficient D increased weakly with increasing pressure from 31 to 61 GPa, though partial melt remains more iron-rich than perovskite up to 61GPa. The results up to the lowermost mantle condition will be discussed in the presentation.

  11. Iron Partitioning in Ferropericlase

    NASA Astrophysics Data System (ADS)

    Braithwaite, J. W. H.; Stixrude, L. P.; Pinilla, C.; Holmstrom, E.

    2015-12-01

    Ferropericlase, (Mg,Fe)O, is the second most abundant mineral in the Earth's lower mantle. Whether iron favours the liquid or solid phase of (Mg,Fe)O has important implications for the Earth's mantle, both chemically and dynamically. As iron is much heavier than magnesium, the partitioning of iron between liquid and solid will lead to a contrast in densities. This difference in density will lead one phase to be more buoyant than the other and would help, in part, to explain how the mantle crystallised from the magma ocean of the Hadean eon to its current state. The partitioning of iron between the two phases is characterized by partition coefficients. Using ab-initio methods, thermodynamic integration and adiabatic switching these coefficients have been determined. Results are presented for pressures encompassing the region between the upper mantle and the core-mantle boundary (10-140GPa).

  12. Heavy element accumulation in Evernia prunastri lichen transplants around a municipal solid waste landfill in central Italy.

    PubMed

    Nannoni, Francesco; Santolini, Riccardo; Protano, Giuseppe

    2015-09-01

    This paper presents the results of a biomonitoring study to evaluate the environmental impact of airborne emissions from a municipal solid waste landfill in central Italy. Concentrations of 11 heavy elements, as well as photosynthetic efficiency and cell membrane integrity were measured in Evernia prunastri lichens transplanted for 4months in 17 monitoring sites around the waste landfill. Heavy element contents were also determined in surface soils. Analytical data indicated that emissions from the landfill affected Cd, Co, Cr, Cu, Ni, Pb, Sb and Zn concentrations in lichens transplanted within the landfill and along the fallout direction. In these sites moderate to severe accumulation of these heavy elements in lichens was coupled with an increase in cell membrane damage and decrease in photosynthetic efficiency. Nevertheless, results indicated that landfill emissions had no relevant impact on lichens, as heavy element accumulation and weak stress symptoms were detected only in lichen transplants from sites close to solid waste. The appropriate management of this landfill poses a low risk of environmental contamination by heavy elements.

  13. Gallic acid and tannase accumulation during fungal solid state culture of a tannin-rich desert plant (Larrea tridentata Cov.).

    PubMed

    Treviño-Cueto, B; Luis, M; Contreras-Esquivel, J C; Rodríguez, R; Aguilera, A; Aguilar, C N

    2007-02-01

    Larrea tridentata (Sesse & Mocino ex DC.) Coville, also known as Larrea, gobernadora, chaparral, or creosote bush, is a shrubby plant which dominates some areas of the desert southwest in the United States and Northern Mexico and its use has not been exploited and standardized. In this study, gobernadora was studied to evaluate its potential use for support of solid state culture. Influence of two minimal media added with gobernadora powder as the sole carbon source and inducer of tannin-degrading enzymes was evaluated. Cultures were initially 70% moisture, had a pH of 5.5 and were inoculated with Aspergillus niger Aa-20 at 2 x 10(7) spores per gram of media. Analysis of pH, moisture, tannin uptake, gallic acid accumulation and tannase production were evaluated. Results indicated a high content of condensed (39.4%dm) and hydrolysable (22.8%dm) tannins. Invasion capacity of fungal growth was of 0.15 mmh(-1). Tannase production reached values of 1040 Ul(-1) at 43 h of culture. During the first 48 h of culture, the concentration of gallic acid accumulation was 0.33 gl(-1). Gobernadora is a potential source of gallic acid and tannase production by solid state culture; however, further optimization of the process is needed.

  14. PARTITION INFRARED METHOD FOR TOTAL GASOLINE RANGE ORGANICS IN WATER BASED ON SOLID PHASE MICROEXTRACTION. (R825343)

    EPA Science Inventory

    A new method is described for determining total gasoline-range organics
    (TGRO) in water that combines solid-phase microextraction (SPME) and infrared
    (IR) spectroscopy. In this method, the organic compounds are extracted from
    250-mL of water into a small square (3....

  15. Remodelling of extracellular matrix due to solid stress accumulation during tumour growth

    PubMed Central

    Pirentis, Athanassios P.; Polydorou, Christiana; Papageorgis, Panagiotis; Voutouri, Chrysovalantis; Mpekris, Fotios; Stylianopoulos, Triantafyllos

    2015-01-01

    Solid stresses emerge as the expanding tumour displaces and deforms the surrounding normal tissue, and also as a result of intratumoural component interplay. Among other things, solid stresses are known to induce extensive extracellular matrix synthesis and reorganization. In the present study, we developed a mathematical model of tumour growth that distinguishes the contribution to stress generation by collagenous and non-collagenous tumour structural components, and also investigates collagen fibre remodelling exclusively due to solid stress. To this end, we initially conducted in vivo experiments using an orthotopic mouse model for breast cancer to monitor primary tumour growth and derive the mechanical properties of the tumour. Subsequently, we fitted the mathematical model to experimental data to determine values of the model parameters. According to the model, intratumoural solid stress is compressive, whereas extratumoural stress in the tumour vicinity is compressive in the radial direction and tensile in the periphery. Furthermore, collagen fibres engaged in stress generation only in the peritumoural region, and not in the interior where they were slackened due to the compressive stress state. Peritumoural fibres were driven away from the radial direction, tended to realign tangent to the tumour-host interface, and were also significantly stretched by tensile circumferential stresses. By means of this remodelling, the model predicts that the tumour is enveloped by a progressively thickening capsule of collagen fibres. This prediction is consistent with long-standing observations of tumour encapsulation and histologic sections that we performed, and it further corroborates the expansive growth hypothesis for the capsule formation. PMID:26194953

  16. Rate of production, dissolution and accumulation of biogenic solids in the ocean

    NASA Technical Reports Server (NTRS)

    Arrhenius, G.

    1988-01-01

    The equatorial current system, by its response to global circulation changes, provides a unique recording mechanism for long range climatic oscillations. A permanent record of the changes in rate of upwelling and organic production is generated in the equatorial deep sea sediments, particularly by such biogenic components which are unaffected by secondary dissolution. In order to determine the rates of accumulation of various sedimentary components, a reliable differential measurement of age of the strata must be obtained. Various approaches to this problem are reviewed, and sources of error discussed. Secondary dissolution of calcium carbonate introduces a substantial and variable difference between the dissolution-modified, and hence a priori unknown, rate of deposition on one hand and the rate of accumulation, derivable from the observed concentration, on the other. The cause and magnitude of these variations are of importance, particularly since some current dating schemes are based on assumed constancy in the rate of accumulation of this and, in some cases, also all other sedimentary components. The concepts used in rate evaluation are discussed with emphasis on the difference between the state of dissolution, an observable property of the sediment, and the rate of dissolution, a parameter that requires deduction of the carbonate fraction dissolved, and of the time differential. As a most likely cause of the enhanced state of dissolution of the interglacial carbonate sediments is proposed the lowered rates of biogenic production and deposition, which cause longer exposure of the carbonate microfossils to corrosion in the bioturbated surface layer of the sediment. Historical perspective is included in the discussion in view of the dedication of the Symposium to Hans Pettersson, the leader of the Swedish Deep Sea Expedition 1947-1948, an undertaking that opened a new era in deep sea research and planetary dynamics.

  17. Rate of production, dissolution and accumulation of biogenic solids in the ocean.

    PubMed

    Arrhenius, G

    1988-01-01

    The equatorial current system, by its response to global circulation changes, provides a unique recording mechanism for long range climatic oscillations. A permanent record of the changes in rate of upwelling and organic production is generated in the equatorial deep sea sediments, particularly by such biogenic components which are unaffected by secondary dissolution. In order to determine the rates of accumulation of various sedimentary components, a reliable differential measurement of age of the strata must be obtained. Various approaches to this problem are reviewed, and sources of error discussed. Secondary dissolution of calcium carbonate introduces a substantial and variable difference between the dissolution-modified, and hence a priori unknown, rate of deposition on one hand and the rate of accumulation, derivable from the observed concentration, on the other. The cause and magnitude of these variations are of importance, particularly since some current dating schemes are based on assumed constancy in the rate of accumulation of this and, in some cases, also all other sedimentary components. The concepts used in rate evaluation are discussed with emphasis on the difference between the state of dissolution, an observable property of the sediment, and the rate of dissolution, a parameter that requires deduction of the carbonate fraction dissolved, and of the time differential. As a most likely cause of the enhanced state of dissolution of the interglacial carbonate sediments is proposed the lowered rates of biogenic production and deposition, which cause longer exposure of the carbonate microfossils to corrosion in the bioturbated surface layer of the sediment. Historical perspective is included in the discussion in view of the dedication of the Symposium to Hans Pettersson, the leader of the Swedish Deep Sea Expedition 1947-1948, an undertaking that opened a new era in deep sea research and planetary dynamics.

  18. Effect of HCl/SO₂₃/NH₃/O₂₃and mineral sorbents on the partitioning behaviour of heavy metals during the thermal treatment of solid wastes.

    PubMed

    Huang, Qunxing; Cai, Xu; Alhadj Mallah, Moussa Mallaye; Chi, Yong; Yan, Jianhua

    2015-01-01

    The high concentration of heavy metals in solid wastes may cause serious pollution during thermal treatment. We have investigated, theoretically and experimentally, the effects of several important flue gas species and mineral sorbents on the partitioning behaviour of four major heavy metals (cadmium, lead, zinc and copper) which are often present in municipal solid waste (MSW). Their concentrations in bottom ash, fly ash and flue gas were quantified when model MSW samples were treated thermally under different conditions. The evaporation ratio of the four metals, excluding Cu, increased with decreasing oxygen concentration. The presence of HCl promotes heavy metal evaporation by preventing the formation of stable metallic species, especially for Zn (evaporation of more than 20%). An increase in oxygen concentration has a negative influence on the effect of HCl. In the presence of SO₂, Cd and Pb exhibited a higher evaporation ratio, while Zn and Cu were insensitive to the change. SO₂also inhibits Cd vaporization in an oxidative atmosphere. The effect of NH3 on reducing the metal volatilization rate was established indirectly. Calcium oxide addition enhances metal evaporation except for that of Zn (which shows a decrease of 38%). Although desulphurization by calcium injection decreases the volume of acid gas, calcium affects heavy metal pollution control adversely. The presence or addition of SiO₂- or Al₂O₃-containing minerals can lead to the formation of stable metallic salts. This may favour the control of Cd, Pb, Zn and Cu volatilization up to 13%, 50%, 17.5% and 19%, respectively.

  19. Determining the effect of solid and liquid vectors on the gaseous interfacial area and oxygen transfer rates in two-phase partitioning bioreactors.

    PubMed

    Quijano, Guillermo; Rocha-Ríos, José; Hernández, Maria; Villaverde, Santiago; Revah, Sergio; Muñoz, Raúl; Thalasso, Frédéric

    2010-03-15

    The effect of liquid and solid transfer vectors (silicone oil and Desmopan, respectively) on the gaseous interfacial area (a(g)) was evaluated in a two-phase partitioning bioreactor (TPPB) using fresh mineral salt medium and the cultivation broth of a toluene degradation culture (Pseudomonas putida DOT-T1E cultures continuously cultivated with and without silicone oil at low toluene loading rates). Higher values of a(g) were recorded in the presence of both silicone oil and Desmopan compared to the values obtained in the absence of a vector, regardless of the aqueous medium tested (1.6 and 3 times higher, respectively, using fresh mineral salt medium). These improvements in a(g) were well correlated to the oxygen mass transfer enhancements supported by the vectors (1.3 and 2.5 for liquid and solid vectors, respectively, using fresh medium). In this context, oxygen transfer rates of 2.5 g O(2)L(-1)h(-1) and 1.3 g O(2)L(-1)h(-1) were recorded in the presence of Desmopan and silicone oil, respectively, which are in agreement with previously reported values in literature. These results suggest that mass transfer enhancements in TPPBs might correspond to an increase in a(g) rather than to the establishment of a high-performance gas/vector/water transfer pathway.

  20. Partition search

    SciTech Connect

    Ginsberg, M.L.

    1996-12-31

    We introduce a new form of game search called partition search that incorporates dependency analysis, allowing substantial reductions in the portion of the tree that needs to be expanded. Both theoretical results and experimental data are presented. For the game of bridge, partition search provides approximately as much of an improvement over existing methods as {alpha}-{beta} pruning provides over minimax.

  1. Solid-solution partitioning and thionation of diphenylarsinic acid in a flooded soil under the impact of sulfate and iron reduction.

    PubMed

    Zhu, Meng; Tu, Chen; Hu, Xuefeng; Zhang, Haibo; Zhang, Lijuan; Wei, Jing; Li, Yuan; Luo, Yongming; Christie, Peter

    2016-11-01

    Diphenylarsinic acid (DPAA) is a major organic arsenic (As) compound derived from abandoned chemical weapons. The solid-solution partitioning and transformation of DPAA in flooded soils are poorly understood but are of great concern. The identification of the mechanisms responsible for the mobilization and transformation of DPAA may help to develop effective remediation strategies. Here, soil and Fe mineral incubation experiments were carried out to elucidate the partitioning and transformation of DPAA in anoxic (without addition of sulfate or sodium lactate) and sulfide (with the addition of sulfate and sodium lactate) soil and to examine the impact of sulfate and Fe(III) reduction on these processes. Results show that DPAA was more effectively mobilized and thionated in sulfide soil than in anoxic soil. At the initial incubation stages (0-4weeks), 6.7-74.5% of the total DPAA in sulfide soil was mobilized likely by sorption competition with sodium lactate. At later incubation stage (4-8weeks), DPAA was almost completely released into the solution likely due to the near-complete Fe(III) reduction. Scanning transmission X-ray microscopy (STXM) results provide further direct evidence of elevated DPAA release coupled with Fe(III) reduction in sulfide environments. The total DPAA fraction decreased significantly to 24.5% after two weeks and reached 3.4% after eight weeks in sulfide soil, whereas no obvious elimination of DPAA occurred in anoxic soil at the initial two weeks and the total DPAA fraction decreased to 10.9% after eight weeks. This can be explained in part by the enhanced mobilization of DPAA and sulfate reduction in sulfide soil compared with anoxic soil. These results suggest that under flooded soil conditions, Fe(III) and sulfate reduction significantly promote DPAA mobilization and thionation, respectively, and we suggest that it is essential to consider both sulfate and Fe(III) reduction to further our understanding of the environmental fate of DPAA.

  2. Sucrose phosphate synthase activity and the co-ordination of carbon partitioning during sucrose and amino acid accumulation in desiccation-tolerant leaf material of the C4 resurrection plant Sporobolus stapfianus during dehydration.

    PubMed

    Whittaker, Anne; Martinelli, Tommaso; Farrant, Jill M; Bochicchio, Adriana; Vazzana, Concetta

    2007-01-01

    Both sucrose and amino acids accumulate in desiccation-tolerant leaf material of the C(4) resurrection plant, Sporobolus stapfianus Gandoger (Poaceae). The present investigation was aimed at examining sucrose phosphate synthase (SPS) activity and various metabolic checkpoints involved in the co-ordination of carbon partitioning between these competing pathways during dehydration. In the initial phase of dehydration, photosynthesis and starch content declined to immeasurable levels, whilst significant increases in hexose sugars, sucrose, and amino acids were associated with concomitant significant increases in SPS and pyruvate kinase (PK) activities, and maximal activity levels of phosphoenolpyruvate carboxylase (PEPCase), NADP-dependent isocitrate dehydrogenase (NADP-ICDH), and NADH-dependent glutamate synthase (NADH-GOGAT). The next phase of dehydration was characterized by changes in metabolism coinciding with net hexose sugar phosphorylation. This phase was characterized by a further significant increase in sucrose accumulation, with increased rates of net sucrose accumulation and maximum rates of SPS activity measured under both saturating and limiting (inhibitory) conditions. SPS protein was also increased. The stronger competitive edge of SPS for carbon entering glycolysis during hexose phosphorylation was also demonstrated by the further decrease in respiration and the simultaneous, significant decline in both PEPCase and PK activities. A decreased anabolic demand for 2-oxoglutarate (2OG), which remained constant, was shown by the co-ordinated decrease in GOGAT. It is proposed that the further increase in amino acids in this phase of dehydration may be in part attributable to the breakdown of insoluble proteins.

  3. Accumulation and fractionation of trace metals in a Tunisian calcareous soil amended with farmyard manure and municipal solid waste compost.

    PubMed

    Achiba, W Ben; Lakhdar, Abdelbasset; Gabteni, Noureddine; Du Laing, Gijs; Verloo, Marc; Boeckx, Pascal; Van Cleemput, Oswald; Jedidi, Naceur; Gallali, Tahar

    2010-04-15

    A field plots experiment was carried out to assess the effects of repeated application of municipal solid waste compost in comparison to farmyard manure on the accumulation and distribution of trace metals, as well as organic carbon and nitrogen in Tunisian calcareous soil. Compared with untreated soil, the application of the two organic amendments significantly increased the organic carbon and nitrogen contents of the soil. Particle-size fractionations showed that carbon and nitrogen were mainly found to occur in the macro-organic matter fraction (80%). The two organic amendments significantly increased organic carbon in the macro-organic and mineral >150 microm fraction and the 150-50 microm fraction, as well as the organic nitrogen in 150-50 microm and macro-organic fraction. Compared with farmyard manure, municipal solid waste compost significantly increased total Cd, Cu, Pb and Zn contents in the topsoil. These trace metals were mainly present in the macro-organic matter fraction. Significant increases of Cu, Zn and Pb were detected in the 150-50 microm, <50 microm and macro-organic fractions after application of municipal solid waste compost. A significant increase of Cd content was only observed in the 150-50 microm fraction. The trace metals also showed different fractionation patterns when the BCR sequential extraction scheme was applied on untreated and compost-treated soil. The residual fraction was found to be the major fraction, especially for Cu, Cr, Ni and Zn. In contrast, Cd was mainly present in the acid-extractable and reducible fraction, whereas Pb was mainly associated with the reducible fraction.

  4. Polyparameter linear free energy models for polyacrylate fiber-water partition coefficients to evaluate the efficiency of solid-phase microextraction.

    PubMed

    Endo, Satoshi; Droge, Steven T J; Goss, Kai-Uwe

    2011-02-15

    The fiber-water partition coefficient, K(fw), is decisive for performance of solid-phase microextraction (SPME) techniques in organic chemical analyses. In this study, polyacrylate (PA)-coated fiber was evaluated for its K(fw) values toward diverse neutral organic compounds. Literature K(fw) data were thoroughly evaluated, and additional K(fw) values for 69 compounds were measured in phosphate-buffered saline (PBS) solution at 37 °C. These K(fw) data, spanning over 6 orders of magnitude, were used to construct polyparameter linear free energy relationship (PP-LFER) models. The PP-LFER models fit well to the data with a standard deviation of 0.15-0.23 log units. Additional experiments indicated that the differences in temperature (25 vs 37 °C), electrolyte concentrations (pure water vs PBS), and conditioning methods (heat vs methanol) had only minor influences (<0.3 log units) on K(fw). Using the established PP-LFERs, the SPME extraction efficiency of PA coating toward compounds of differing polarity was evaluated in comparison to poly(dimethylsiloxane) (PDMS) coating. PA exhibited higher extraction capacities for H-bond donor compounds (e.g., phenols, anilines, amides, and many drugs and pesticides) with the estimated K(fw) values being 1-4 log units higher than those of PDMS. Also, PA was shown to be more efficient than PDMS for hydrophobic aromatic compounds.

  5. Partition Equilibrium

    NASA Astrophysics Data System (ADS)

    Feldman, Michal; Tennenholtz, Moshe

    We introduce partition equilibrium and study its existence in resource selection games (RSG). In partition equilibrium the agents are partitioned into coalitions, and only deviations by the prescribed coalitions are considered. This is in difference to the classical concept of strong equilibrium according to which any subset of the agents may deviate. In resource selection games, each agent selects a resource from a set of resources, and its payoff is an increasing (or non-decreasing) function of the number of agents selecting its resource. While it has been shown that strong equilibrium exists in resource selection games, these games do not possess super-strong equilibrium, in which a fruitful deviation benefits at least one deviator without hurting any other deviator, even in the case of two identical resources with increasing cost functions. Similarly, strong equilibrium does not exist for that restricted two identical resources setting when the game is played repeatedly. We prove that for any given partition there exists a super-strong equilibrium for resource selection games of identical resources with increasing cost functions; we also show similar existence results for a variety of other classes of resource selection games. For the case of repeated games we identify partitions that guarantee the existence of strong equilibrium. Together, our work introduces a natural concept, which turns out to lead to positive and applicable results in one of the basic domains studied in the literature.

  6. Effect of the combined addition of Zn and Pb on partitioning in sediments and their accumulation by the emergent macrophyte Schoenoplectus californicus.

    PubMed

    Arreghini, Silvana; de Cabo, Laura; Serafini, Roberto; de Iorio, Alicia Fabrizio

    2017-01-31

    Wetlands usually provide a natural mechanism that diminishes the transport of toxic compounds to other compartments of the ecosystem by immobilization and accumulation in belowground tissues and/or soil. This study was conducted to assess the ability of Schoenoplectus californicus growing in natural marsh sediments, with zinc and lead addition, to tolerate and accumulate these metals, taking account of the metal distribution in the sediment fractions. The Zn and Pb were mainly found in available (exchangeable) and potentially available (bound to organic matter) forms, respectively. The absorption of Zn and Pb by plants increased in sediments with added metals. Both metals were largely retained in roots (translocation factor < 1). Lead rhizome concentrations only increased significantly in treatments with high doses of metal independently of added Zn. The addition of Zn increased its concentration in roots and shoots significantly, while its concentration in rhizomes only increased when both metals were added together. Zinc concentration in shoots did not reach the toxic level for plants. Zinc and Pb concentrations in roots were high, but they were not sufficient to reduce biomass growth.

  7. PREDICTING THE BIOAVAILABILITY OF COPPER AND ZINC IN SOILS: MODELING THE PARTITIONING OF POTENTIALLY BIOAVAILABLE COPPER AND ZINC FROM SOIL SOLID TO SOIL SOLUTION

    EPA Science Inventory

    This research produced statistically based, semi-mechanistic models describing partitioning of Cu and Zn in 40 soils from the US, Canada, the UK, the Netherlands, and Chile with widely varying characteristics. Two different types of models were constructed, partitioning models ...

  8. Mechanisms of salt tolerance in habanero pepper plants (Capsicum chinense Jacq.): Proline accumulation, ions dynamics and sodium root-shoot partition and compartmentation

    PubMed Central

    Bojórquez-Quintal, Emanuel; Velarde-Buendía, Ana; Ku-González, Ángela; Carillo-Pech, Mildred; Ortega-Camacho, Daniela; Echevarría-Machado, Ileana; Pottosin, Igor; Martínez-Estévez, Manuel

    2014-01-01

    Despite its economic relevance, little is known about salt tolerance mechanisms in pepper plants. To address this question, we compared differences in responses to NaCl in two Capsicum chinense varieties: Rex (tolerant) and Chichen-Itza (sensitive). Under salt stress (150 mM NaCl over 7 days) roots of Rex variety accumulated 50 times more compatible solutes such as proline compared to Chichen-Itza. Mineral analysis indicated that Na+ is restricted to roots by preventing its transport to leaves. Fluorescence analysis suggested an efficient Na+ compartmentalization in vacuole-like structures and in small intracellular compartments in roots of Rex variety. At the same time, Na+ in Chichen-Itza plants was compartmentalized in the apoplast, suggesting substantial Na+ extrusion. Rex variety was found to retain more K+ in its roots under salt stress according to a mineral analysis and microelectrode ion flux estimation (MIFE). Vanadate-sensitive H+ efflux was higher in Chichen-Itza variety plants, suggesting a higher activity of the plasma membrane H+-ATPase, which fuels the extrusion of Na+, and, possibly, also the re-uptake of K+. Our results suggest a combination of stress tolerance mechanisms, in order to alleviate the salt-induced injury. Furthermore, Na+ extrusion to apoplast does not appear to be an efficient strategy for salt tolerance in pepper plants. PMID:25429292

  9. Mechanisms of salt tolerance in habanero pepper plants (Capsicum chinense Jacq.): Proline accumulation, ions dynamics and sodium root-shoot partition and compartmentation.

    PubMed

    Bojórquez-Quintal, Emanuel; Velarde-Buendía, Ana; Ku-González, Angela; Carillo-Pech, Mildred; Ortega-Camacho, Daniela; Echevarría-Machado, Ileana; Pottosin, Igor; Martínez-Estévez, Manuel

    2014-01-01

    Despite its economic relevance, little is known about salt tolerance mechanisms in pepper plants. To address this question, we compared differences in responses to NaCl in two Capsicum chinense varieties: Rex (tolerant) and Chichen-Itza (sensitive). Under salt stress (150 mM NaCl over 7 days) roots of Rex variety accumulated 50 times more compatible solutes such as proline compared to Chichen-Itza. Mineral analysis indicated that Na(+) is restricted to roots by preventing its transport to leaves. Fluorescence analysis suggested an efficient Na(+) compartmentalization in vacuole-like structures and in small intracellular compartments in roots of Rex variety. At the same time, Na(+) in Chichen-Itza plants was compartmentalized in the apoplast, suggesting substantial Na(+) extrusion. Rex variety was found to retain more K(+) in its roots under salt stress according to a mineral analysis and microelectrode ion flux estimation (MIFE). Vanadate-sensitive H(+) efflux was higher in Chichen-Itza variety plants, suggesting a higher activity of the plasma membrane H(+)-ATPase, which fuels the extrusion of Na(+), and, possibly, also the re-uptake of K(+). Our results suggest a combination of stress tolerance mechanisms, in order to alleviate the salt-induced injury. Furthermore, Na(+) extrusion to apoplast does not appear to be an efficient strategy for salt tolerance in pepper plants.

  10. GEMAS: prediction of solid-solution phase partitioning coefficients (Kd) for oxoanions and boric acid in soils using mid-infrared diffuse reflectance spectroscopy.

    PubMed

    Janik, Leslie J; Forrester, Sean T; Soriano-Disla, José M; Kirby, Jason K; McLaughlin, Michael J; Reimann, Clemens

    2015-02-01

    The authors' aim was to develop rapid and inexpensive regression models for the prediction of partitioning coefficients (Kd), defined as the ratio of the total or surface-bound metal/metalloid concentration of the solid phase to the total concentration in the solution phase. Values of Kd were measured for boric acid (B[OH]3(0)) and selected added soluble oxoanions: molybdate (MoO4(2-)), antimonate (Sb[OH](6-)), selenate (SeO4(2-)), tellurate (TeO4(2-)) and vanadate (VO4(3-)). Models were developed using approximately 500 spectrally representative soils of the Geochemical Mapping of Agricultural Soils of Europe (GEMAS) program. These calibration soils represented the major properties of the entire 4813 soils of the GEMAS project. Multiple linear regression (MLR) from soil properties, partial least-squares regression (PLSR) using mid-infrared diffuse reflectance Fourier-transformed (DRIFT) spectra, and models using DRIFT spectra plus analytical pH values (DRIFT + pH), were compared with predicted log K(d + 1) values. Apart from selenate (R(2)  = 0.43), the DRIFT + pH calibrations resulted in marginally better models to predict log K(d + 1) values (R(2)  = 0.62-0.79), compared with those from PSLR-DRIFT (R(2)  = 0.61-0.72) and MLR (R(2)  = 0.54-0.79). The DRIFT + pH calibrations were applied to the prediction of log K(d + 1) values in the remaining 4313 soils. An example map of predicted log K(d + 1) values for added soluble MoO4(2-) in soils across Europe is presented. The DRIFT + pH PLSR models provided a rapid and inexpensive tool to assess the risk of mobility and potential availability of boric acid and selected oxoanions in European soils. For these models to be used in the prediction of log K(d + 1) values in soils globally, additional research will be needed to determine if soil variability is accounted on the calibration.

  11. Understanding sugar yield loss and enzyme inhibition due to oligosaccharides accumulation during high solids-loading enzymatic hydrolisis.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During enzymatic hydrolysis of biomass, polysaccharides are cleaved by glycosyl hydrolases to soluble oligosaccharides and further hydrolyzed by ß-glucosidase, ß-xylosidase and other enzymes to monomeric sugars. However, not all oligosaccharides can be fully hydrolyzed and they may accumulate to 18-...

  12. Analysis of fluid-solid interaction in MHD natural convection in a square cavity equally partitioned by a vertical flexible membrane

    NASA Astrophysics Data System (ADS)

    Mehryan, S. A. M.; Ghalambaz, Mohammad; Ismael, Muneer A.; Chamkha, Ali J.

    2017-02-01

    This paper investigates numerically the problem of unsteady natural convection inside a square cavity partitioned by a flexible impermeable membrane. The finite element method with the arbitrary Lagrangian-Eulerian (ALE) technique has been used to model the interaction of the fluid and the membrane. The horizontal walls of the cavity are kept adiabatic while the vertical walls are kept isothermal at different temperatures. A uniform magnetic field is applied onto the cavity with different orientations. The cavity has been provided by two eyelets to compensate volume changes due the movement of the flexible membrane. A parametric study is carried out for the pertinent parameters, which are the Rayleigh number (105-108), Hartmann number (0-200) and the orientation of the magnetic field (0-180°). The change in the Hartmann number affects the shape of the membrane and the heat transfer in the cavity. The angle of the magnetic field orientation also significantly affects the shape of the membrane and the heat transfer in the cavity.

  13. Design configurations affecting flow pattern and solids accumulation in horizontal free water and subsurface flow constructed wetlands.

    PubMed

    Pedescoll, A; Sidrach-Cardona, R; Sánchez, J C; Carretero, J; Garfi, M; Bécares, E

    2013-03-01

    The aim of this study was to evaluate the effect of different horizontal constructed wetland (CW) design parameters on solids distribution, loss of hydraulic conductivity over time and hydraulic behaviour, in order to assess clogging processes in wetlands. For this purpose, an experimental plant with eight CWs was built at mesocosm scale. Each CW presented a different design characteristic, and the most common CW configurations were all represented: free water surface flow (FWS) with different effluent pipe locations, FWS with floating macrophytes and subsurface flow (SSF), and the presence of plants and specific species (Typha angustifolia and Phragmites australis) was also considered. The loss of the hydraulic conductivity of gravel was greatly influenced by the presence of plants and organic load (representing a loss of 20% and c.a. 10% in planted wetlands and an overloaded system, respectively). Cattail seems to have a greater effect on the development of clogging since its below-ground biomass weighed twice as much as that of common reed. Hydraulic behaviour was greatly influenced by the presence of a gravel matrix and the outlet pipe position. In strict SSF CW, the water was forced to cross the gravel and tended to flow diagonally from the top inlet to the bottom outlet (where the inlet and outlet pipes were located). However, when FWS was considered, water preferentially flowed above the gravel, thus losing half the effective volume of the system. Only the presence of plants seemed to help the water flow partially within the gravel matrix.

  14. Celluclast and Cellic® CTec2: Saccharification/fermentation of wheat straw, solid-liquid partition and potential of enzyme recycling by alkaline washing.

    PubMed

    Rodrigues, Ana Cristina; Haven, Mai Østergaard; Lindedam, Jane; Felby, Claus; Gama, Miguel

    2015-11-01

    The hydrolysis/fermentation of wheat straw and the adsorption/desorption/deactivation of cellulases were studied using Cellic(®) CTec2 (Cellic) and Celluclast mixed with Novozyme 188. The distribution of enzymes - cellobiohydrolase I (Cel7A), endoglucanase I (Cel7B) and β-glucosidase - of the two formulations between the residual substrate and supernatant during the course of enzymatic hydrolysis and fermentation was investigated. The potential of recyclability using alkaline wash was also studied. The efficiency of hydrolysis with an enzyme load of 10 FPU/g cellulose reached >98% using Cellic(®) CTec2, while for Celluclast a conversion of 52% and 81%, was observed without and with β-glucosidase supplementation, respectively. The decrease of Cellic(®) CTec2 activity observed along the process was related to deactivation of Cel7A rather than of Cel7B and β-glucosidase. The adsorption/desorption profiles during hydrolysis/fermentation revealed that a large fraction of active enzymes remained adsorbed to the solid residue throughout the process. Surprisingly, this was the case of Cel7A and β-glucosidase from Cellic, which remained adsorbed to the solid fraction along the entire process. Alkaline washing was used to recover the enzymes from the solid residue. This method allowed efficient recovery of Celluclast enzymes; however, this may be achieved only when minor amounts of cellulose remain present. Regarding the Cellic formulation, neither the presence of cellulose nor lignin restricted an efficient desorption of the enzymes at alkaline pH. This work shows that the recycling strategy must be customized for each particular formulation, since the enzymes found e.g. in Cellic and Celluclast bear quite different behaviour regarding the solid-liquid distribution, stability and cellulose and lignin affinity.

  15. Estimating evolution of δ(13)CH(4) during methanization of municipal solid waste based on chemical reactions, isotope accumulation in products and microbial ecology.

    PubMed

    Vavilin, V A

    2012-01-01

    Natural isotopic composition in substrate may be used to reveal the metabolic pathways of substrate transformation by microbial community. In this paper, a change in δ(13)CH(4) during methanization of reconstituted municipal solid waste was described using a mathematical model based on stoichiometric chemical reactions, equation for the (13)C isotope accumulation in products at the low natural C(13)/C(12) ratio and microbial ecology. A set of experimental data used in the model was taken from Qu et al. (2009a). According to the model, during mesophilic municipal solid waste methanization initially hydrogenotrophic and further aceticlastic methanogenesis dominated. At the final stage hydrogenotrophic methanogenesis followed by acetate oxidation dominated again. In spite of rather high measured values of δ(13)C for CO(2) above -21‰, a sharp decrease in δ(13)CH(4) from -20‰ to -60‰ at the final stage was explained by a larger fractionation against (13)C during methanogenesis from H(2)/H(2)CO(3) due to a kinetic isotope effect when hydrogenotrophic methanogens preferentially take down light (12)C. The model also confirmed that in thermophilic conditions a comparatively stable value of δ(13)CH(4) about -60‰ measured earlier (Qu et al. 2009b) was due to a dominance of hydrogenotrophic methanogenesis during all methanization process of cardboard waste.

  16. Partitioning and lipophilicity in quantitative structure-activity relationships.

    PubMed Central

    Dearden, J C

    1985-01-01

    The history of the relationship of biological activity to partition coefficient and related properties is briefly reviewed. The dominance of partition coefficient in quantitation of structure-activity relationships is emphasized, although the importance of other factors is also demonstrated. Various mathematical models of in vivo transport and binding are discussed; most of these involve partitioning as the primary mechanism of transport. The models describe observed quantitative structure-activity relationships (QSARs) well on the whole, confirming that partitioning is of key importance in in vivo behavior of a xenobiotic. The partition coefficient is shown to correlate with numerous other parameters representing bulk, such as molecular weight, volume and surface area, parachor and calculated indices such as molecular connectivity; this is especially so for apolar molecules, because for polar molecules lipophilicity factors into both bulk and polar or hydrogen bonding components. The relationship of partition coefficient to chromatographic parameters is discussed, and it is shown that such parameters, which are often readily obtainable experimentally, can successfully supplant partition coefficient in QSARs. The relationship of aqueous solubility with partition coefficient is examined in detail. Correlations are observed, even with solid compounds, and these can be used to predict solubility. The additive/constitutive nature of partition coefficient is discussed extensively, as are the available schemes for the calculation of partition coefficient. Finally the use of partition coefficient to provide structural information is considered. It is shown that partition coefficient can be a valuable structural tool, especially if the enthalpy and entropy of partitioning are available. PMID:3905374

  17. Accumulation and spatial distribution of Cd, Cr, and Pb in mulberry from municipal solid waste compost following application of EDTA and (NH4)2SO4.

    PubMed

    Zhao, Shulan; Shang, Xiaojuan; Duo, Lian

    2013-02-01

    Municipal solid waste compost can be used to cropland as soil amendment to supply nutrients and improve soil physical properties. But long-term application of municipal solid waste (MSW) compost may result in accumulation of toxic metals in amended soil. Phytoremediation, especially phytoextraction, is a novel, cost-effective, and environmentally friendly approach that uses metal-accumulating plants to concentrate and remove metals from contaminated soils. Ethylenediaminetetraacetate (EDTA) was applied to metal-contaminated soil to increase the mobility and phytoavailability of metals in soil, thereby increasing the amount of toxic metals accumulated in the upper parts of phytoextracting plants. The objectives of this study were (1) to investigate the accumulation and spatial distribution of toxic metals (Cd, Cr, and Pb) in mulberry from MSW compost with the application of EDTA and (NH(4))(2)SO(4), (2) to examine the effectiveness of EDTA and (NH(4))(2)SO(4) applied together on toxic metals (Cd, Cr, and Pb) removal by mulberry under field conditions, and (3) to evaluate the potential of mulberry for phytoextraction of toxic metals from MSW compost. The tested plant-mulberry had been grown in MSW compost field for 4 years. EDTA solution at five rates (0, 50, 100, 50 mmol L(-1) + 1 g L(-1) (NH(4))(2)SO(4), and 100 mmol L(-1) + 1 g L(-1) (NH(4))(2)SO(4)) was added into mulberry root medium in September 2009. Twenty days later, the plants were harvested and separated into six parts according to plant height. Cd, Cr, and Pb contents in plant samples and MSW compost were analyzed using an atomic absorption spectrophotometer. In the same treatment, Cd, Cr, and Pb concentrations in mulberry shoot were all higher than those in root, and Cd and Pb concentrations in shoot increased from lower to upper parts, reaching the highest in leaves. Significant increases were found in toxic metal concentration in different parts of mulberry with increasing EDTA concentration

  18. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative channel coding scheme called 'Accumulate Repeat Accumulate codes' (ARA). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes, thus belief propagation can be used for iterative decoding of ARA codes on a graph. The structure of encoder for this class can be viewed as precoded Repeat Accumulate (RA) code or as precoded Irregular Repeat Accumulate (IRA) code, where simply an accumulator is chosen as a precoder. Thus ARA codes have simple, and very fast encoder structure when they representing LDPC codes. Based on density evolution for LDPC codes through some examples for ARA codes, we show that for maximum variable node degree 5 a minimum bit SNR as low as 0.08 dB from channel capacity for rate 1/2 can be achieved as the block size goes to infinity. Thus based on fixed low maximum variable node degree, its threshold outperforms not only the RA and IRA codes but also the best known LDPC codes with the dame maximum node degree. Furthermore by puncturing the accumulators any desired high rate codes close to code rate 1 can be obtained with thresholds that stay close to the channel capacity thresholds uniformly. Iterative decoding simulation results are provided. The ARA codes also have projected graph or protograph representation that allows for high speed decoder implementation.

  19. Plasmid Partition Mechanisms.

    PubMed

    Baxter, Jamie C; Funnell, Barbara E

    2014-12-01

    The stable maintenance of low-copy-number plasmids in bacteria is actively driven by partition mechanisms that are responsible for the positioning of plasmids inside the cell. Partition systems are ubiquitous in the microbial world and are encoded by many bacterial chromosomes as well as plasmids. These systems, although different in sequence and mechanism, typically consist of two proteins and a DNA partition site, or prokaryotic centromere, on the plasmid or chromosome. One protein binds site-specifically to the centromere to form a partition complex, and the other protein uses the energy of nucleotide binding and hydrolysis to transport the plasmid, via interactions with this partition complex inside the cell. For plasmids, this minimal cassette is sufficient to direct proper segregation in bacterial cells. There has been significant progress in the last several years in our understanding of partition mechanisms. Two general areas that have developed are (i) the structural biology of partition proteins and their interactions with DNA and (ii) the action and dynamics of the partition ATPases that drive the process. In addition, systems that use tubulin-like GTPases to partition plasmids have recently been identified. In this chapter, we concentrate on these recent developments and the molecular details of plasmid partition mechanisms.

  20. The effect of IGFC warm gas cleanup system conditions on the gas–solid partitioning and form of trace species in coal syngas and their interactions with SOFC anodes

    SciTech Connect

    Trembly, J.P.; Gemmen, R.S.; Bayless, D.J.

    2007-01-01

    The U.S. Department of Energy is currently working on coupling coal gasification and high temperature fuel cell to produce electrical power in a highly efficient manner while being emissions free. Many investigations have already investigated the effects of major coal syngas species such as CO and H2S. However coal contains many trace species and the effect of these species on solid oxide fuel cell anode is not presently known.Warm gas cleanup systems are planned to be used with these advanced power generation systems for the removal of major constituents such as H2S and HCl but the operational parameters of such systems is not well defined at this point in time. This paper focuses on the effect of anticipated warm gas cleanup conditions has on trace specie partitioning between the vapor and condensed phase and the effects the trace vapor species have on the SOFC anode. Results show that Be, Cr, K, Na, V, and Z trace species will form condensed phases and should not effect SOFC anode performance since it is anticipated that the warm gas cleanup systems will have a high removal efficiency of particulate matter. Also the results show that Sb, As, Cd, Hg, Pb, P, and Se trace species form vapor phases and the Sb, As, and P vapor phase species show the ability to form secondary Ni phases in the SOFC anode.

  1. Effect of solids retention time and temperature on waste activated sludge hydrolysis and short-chain fatty acids accumulation under alkaline conditions in continuous-flow reactors.

    PubMed

    Feng, Leiyu; Wang, Hua; Chen, Yinguang; Wang, Qin

    2009-01-01

    The effects of solids retention time (SRT) and temperature on waste activated sludge (WAS) hydrolysis and short-chain fatty acids (SCFAs) accumulation were investigated in a series of continuous-flow reactors at pH 10. The experimental results showed that the increase of either SRT or temperature benefited the hydrolysis of WAS and the production of SCFAs. The changes in SRT gave also impact on the percentage of acetic and propionic acids in the fermentative SCFAs, but little influence on that of the slightly long-chain SCFAs, such as n-butyric, iso-butyric, n-valeric and iso-valeric acids. Compared with the control (pH unadjusted) experiment, at SRT of 12d and temperature of 20 degrees C the concentration of SCFAs produced at pH 10 increased from 261.2 to 933.5mg COD/L, and the propionic acid percentage improved from 11.7 to 16.0%. It can be concluded from this investigation that the efficient continuous production of SCFAs at pH 10 is feasible.

  2. STRUCTURAL DYNAMICS OF METAL PARTITIONING TO MINERAL SURFACES

    EPA Science Inventory

    The conceptual understanding of surface complexation reactions that control trace element partitioning to mineral surfaces is limited by the assumption that the solid reactant possesses a finite, time-invariant population of surface functional groups. This assumption has limited...

  3. Partitioning planning studies: Preliminary evaluation of metal and radionuclide partitioning the high-temperature thermal treatment systems

    SciTech Connect

    Liekhus, K.; Grandy, J.; Chambers, A.

    1997-03-01

    A preliminary study of toxic metals and radionuclide partitioning during high-temperature processing of mixed waste has been conducted during Fiscal Year 1996 within the Environmental Management Technology Evaluation Project. The study included: (a) identification of relevant partitioning mechanisms that cause feed material to be distributed between the solid, molten, and gas phases within a thermal treatment system; (b) evaluations of existing test data from applicable demonstration test programs as a means to identify and understand elemental and species partitioning; and, (c) evaluation of theoretical or empirical partitioning models for use in predicting elemental or species partitioning in a thermal treatment system. This preliminary study was conducted to identify the need for and the viability of developing the tools capable of describing and predicting toxic metals and radionuclide partitioning in the most applicable mixed waste thermal treatment processes. This document presents the results and recommendations resulting from this study that may serve as an impetus for developing and implementing these predictive tools.

  4. Accumulate-Repeat-Accumulate-Accumulate-Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Thorpe, Jeremy

    2004-01-01

    Inspired by recently proposed Accumulate-Repeat-Accumulate (ARA) codes [15], in this paper we propose a channel coding scheme called Accumulate-Repeat-Accumulate-Accumulate (ARAA) codes. These codes can be seen as serial turbo-like codes or as a subclass of Low Density Parity Check (LDPC) codes, and they have a projected graph or protograph representation; this allows for a high-speed iterative decoder implementation using belief propagation. An ARAA code can be viewed as a precoded Repeat-and-Accumulate (RA) code with puncturing in concatenation with another accumulator, where simply an accumulator is chosen as the precoder; thus ARAA codes have a very fast encoder structure. Using density evolution on their associated protographs, we find examples of rate-lJ2 ARAA codes with maximum variable node degree 4 for which a minimum bit-SNR as low as 0.21 dB from the channel capacity limit can be achieved as the block size goes to infinity. Such a low threshold cannot be achieved by RA or Irregular RA (IRA) or unstructured irregular LDPC codes with the same constraint on the maximum variable node degree. Furthermore by puncturing the accumulators we can construct families of higher rate ARAA codes with thresholds that stay close to their respective channel capacity thresholds uniformly. Iterative decoding simulation results show comparable performance with the best-known LDPC codes but with very low error floor even at moderate block sizes.

  5. Ionic partitioning and stomatal regulation

    PubMed Central

    Sanoubar, Rabab; Orsini, Francesco; Gianquinto, Giorgio Prosdocimi

    2013-01-01

    Vegetable grafting is commonly claimed to improve crop’s tolerance to biotic and abiotic stresses, including salinity. Although the use of inter-specific graftings is relatively common, whether the improved salt tolerance should be attributed to the genotypic background rather than the grafting per se is a matter of discussion among scientists. It is clear that most of published research has to date overlooked the issue, with the mutual presence of self-grafted and non-grafted controls resulting to be quite rare within experimental evidences. It was recently demonstrated that the genotype of the rootstock and grafting per se are responsible respectively for the differential ion accumulation and partitioning as well as to the stomatal adaptation to the stress. The present paper contributes to the ongoing discussion with further data on the differences associated to salinity response in a range of grafted melon combinations. PMID:24309549

  6. Accumulate-Repeat-Accumulate-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Samuel; Thorpe, Jeremy

    2007-01-01

    Accumulate-repeat-accumulate-accumulate (ARAA) codes have been proposed, inspired by the recently proposed accumulate-repeat-accumulate (ARA) codes. These are error-correcting codes suitable for use in a variety of wireless data-communication systems that include noisy channels. ARAA codes can be regarded as serial turbolike codes or as a subclass of low-density parity-check (LDPC) codes, and, like ARA codes they have projected graph or protograph representations; these characteristics make it possible to design high-speed iterative decoders that utilize belief-propagation algorithms. The objective in proposing ARAA codes as a subclass of ARA codes was to enhance the error-floor performance of ARA codes while maintaining simple encoding structures and low maximum variable node degree.

  7. Partitioning Breaks Communities

    NASA Astrophysics Data System (ADS)

    Reid, Fergal; McDaid, Aaron; Hurley, Neil

    Considering a clique as a conservative definition of community structure, we examine how graph partitioning algorithms interact with cliques. Many popular community-finding algorithms partition the entire graph into non-overlapping communities. We show that on a wide range of empirical networks, from different domains, significant numbers of cliques are split across the separate partitions produced by these algorithms. We then examine the largest connected component of the subgraph formed by retaining only edges in cliques, and apply partitioning strategies that explicitly minimise the number of cliques split. We further examine several modern overlapping community finding algorithms, in terms of the interaction between cliques and the communities they find, and in terms of the global overlap of the sets of communities they find. We conclude that, due to the connectedness of many networks, any community finding algorithm that produces partitions must fail to find at least some significant structures. Moreover, contrary to traditional intuition, in some empirical networks, strong ties and cliques frequently do cross community boundaries; much community structure is fundamentally overlapping and unpartitionable in nature.

  8. Influence of porewater sulfide on methylmercury production and partitioning in sulfate-impacted lake sediments.

    PubMed

    Bailey, Logan T; Mitchell, Carl P J; Engstrom, Daniel R; Berndt, Michael E; Coleman Wasik, Jill K; Johnson, Nathan W

    2017-02-15

    In low-sulfate and sulfate-limited freshwater sediments, sulfate loading increases the production of methylmercury (MeHg), a potent and bioaccumulative neurotoxin. Sulfate loading to anoxic sediments leads to sulfide production that can inhibit mercury methylation, but this has not been commonly observed in freshwater lakes and wetlands. In this study, sediments were collected from sulfate-impacted, neutral pH, surface water bodies located downstream from ongoing and historic mining activities to examine how chronic sulfate loading produces porewater sulfide, and influences MeHg production and transport. Sediments were collected over two years, during several seasons from lakes with a wide range of overlying water sulfate concentration. Samples were characterized for in-situ solid phase and porewater MeHg, Hg methylation potentials via incubations with enriched stable Hg isotopes, and sulfur, carbon, and iron content and speciation. Porewater sulfide reflected historic sulfur loading and was strongly related to the extractable iron content of sediment. Overall, methylation potentials were consistent with the accumulation of MeHg on the solid phase, but both methylation potentials and MeHg were significantly lower at chronically sulfate-impacted sites with a low solid-phase Fe:S ratio. At these heavily sulfate-impacted sites that also contained elevated porewater sulfide, both MeHg production and partitioning are influenced: Hg methylation potentials and sediment MeHg concentrations are lower, but occasionally porewater MeHg concentrations in sediment are elevated, particularly in the spring. The dual role of sulfide as a ligand for inorganic mercury (decreasing bioavailability) and methylmercury (increasing partitioning into porewater) means that elucidating the role of iron and sulfur loads as they define porewater sulfide is key to understanding sulfate's influence on MeHg production and partitioning in sulfate-impacted freshwater sediment.

  9. Equilibration timescale of atmospheric secondary organic aerosol partitioning

    NASA Astrophysics Data System (ADS)

    Shiraiwa, Manabu; Seinfeld, John H.

    2012-12-01

    Secondary organic aerosol (SOA) formed from partitioning of oxidation products of anthropogenic and biogenic volatile organic compounds (VOCs) accounts for a substantial portion of atmospheric particulate matter. In describing SOA formation, it is generally assumed that VOC oxidation products rapidly adopt gas-aerosol equilibrium. Here we estimate the equilibration timescale, τeq, of SOA gas-particle partitioning using a state-of-the-art kinetic flux model. τeq is found to be of order seconds to minutes for partitioning of relatively high volatility organic compounds into liquid particles, thereby adhering to equilibrium gas-particle partitioning. However, τeq increases to hours or days for organic aerosol associated with semi-solid particles, low volatility, large particle size, and low mass loadings. Instantaneous equilibrium partitioning may lead to substantial overestimation of particle mass concentration and underestimation of gas-phase concentration.

  10. FNAS phase partitions

    NASA Technical Reports Server (NTRS)

    Vanalstine, James M.

    1993-01-01

    Project NAS8-36955 D.O. #100 initially involved the following tasks: (1) evaluation of various coatings' ability to control wall wetting and surface zeta potential expression; (2) testing various methods to mix and control the demixing of phase systems; and (3) videomicroscopic investigation of cell partition. Three complementary areas were identified for modification and extension of the original contract. They were: (1) identification of new supports for column cell partition; (2) electrokinetic detection of protein adsorption; and (3) emulsion studies related to bioseparations.

  11. Trace element partitioning between ionic crystal and liquid

    NASA Technical Reports Server (NTRS)

    Tsang, T.; Philpotts, J. A.; Yin, L.

    1978-01-01

    The partitioning of trace elements between ionic crystals and the melt has been correlated with lattice energy of the host. The solid-liquid partition coefficient has been expressed in terms of the difference in relative ionic radius of the trace element and the homogeneous and heterogeneous strain of the host lattice. Predictions based on this model appear to be in general agreement with data for alkali nitrates and for rare-earth elements in natural garnet phenocrysts.

  12. Manganese As a Metal Accumulator

    EPA Science Inventory

    Manganese deposits in water distribution systems accumulate metals, radionuclides and oxyanions by a combination of surface complexation, adsorption and solid substitution, as well as a combination of oxidation followed by manganese reduction and sorption of the oxidized constitu...

  13. Solute partitioning and filtration by extracellular matrices

    PubMed Central

    Hofmann, Christina L.; Ferrell, Nicholas; Schnell, Lisa; Dubnisheva, Anna; Zydney, Andrew L.; Yurchenco, Peter D.; Roy, Shuvo

    2009-01-01

    The physiology of glomerular filtration remains mechanistically obscure despite its importance in disease. The correspondence between proteinuria and foot process effacement suggests podocytes as the locus of the filtration barrier. If so, retained macromolecules ought to accumulate at the filtration barrier, an effect called concentration polarization. Literature data indicate macromolecule concentrations decrease from subendothelial to subepithelial glomerular basement membrane (GBM), as would be expected if the GBM were itself the filter. The objective of this study was to obtain insights into the possible role of the GBM in protein retention by performing fundamental experimental and theoretical studies on the properties of three model gels. Solute partitioning and filtration through thin gels of a commercially available laminin-rich extracellular matrix, Matrigel, were measured using a polydisperse polysaccharide tracer molecule, Ficoll 70. Solute partitioning into laminin gels and lens basement membrane (LBM) were measured using Ficoll 70. A novel model of a laminin gel was numerically simulated, as well as a mixed structure-random-fiber model for LBM. Experimental partitioning was predicted by numerical simulations. Sieving coefficients through thin gels of Matrigel were size dependent and strongly flux dependent. The observed flux dependence arose from compression of the gel in response to the applied pressure. Gel compression may alter solute partitioning into extracellular matrix at physiologic pressures present in the glomerular capillary. This suggests a physical mechanism coupling podocyte structure to permeability characteristics of the GBM. PMID:19587146

  14. Airborne phthalate partitioning to cotton clothing

    NASA Astrophysics Data System (ADS)

    Morrison, Glenn; Li, Hongwan; Mishra, Santosh; Buechlein, Melissa

    2015-08-01

    Accumulation on indoor surfaces and fabrics can increase dermal uptake and non-dietary ingestion of semi-volatile organic compounds. To better understand the potential for dermal uptake of phthalates from clothing, we measured the mass accumulation on cotton fabrics of two phthalate esters commonly identified in indoor air: diethylphthalate (DEP) and di-n-butyl phthalate (DnBP). In 10-day chamber experiments, we observed strong air-to-cloth partitioning of these phthalates to shirts and jean material. Area-normalized partition coefficients ranged from 209 to 411 (μg/m2)/(μg/m3) for DEP and 2850 to 6580 (μg/m2)/(μg/m3) for DnBP. Clothing volume-normalized partition coefficients averaged 2.6 × 105 (μg/m3)/(μg/m3) for DEP and 3.9 × 106 (μg/m3)/(μg/m3) for DnBP. At equilibrium, we estimate that a typical set of cotton clothing can sorb DnBP from the equivalent of >10,000 m3 of indoor air, thereby substantially decreasing external mass-transfer barriers to dermal uptake. Further, we estimate that a significant fraction of a child's body burden of DnBP may come from mouthing fabric material that has been equilibrated with indoor air.

  15. Cadmium accumulation by a Citrobacter sp. immobilized on gel and solid supports: applicability to the treatment of liquid wastes containing heavy metal cations

    SciTech Connect

    Macaskie, L.E.; Wates, J.M.; Dean, A.C.R.

    1987-01-01

    Polyacrylamide gel-immobilized cells of a Citrobacter sp. removed cadmium from flows supplemented with glycerol 2-phosphate, the metal uptake mechanism being mediated by the activity of a cell-bound phosphatase that precipitates liberated inorganic phosphate with heavy metals at the cell surface. The constraints of elevated flow rate and temperature were investigated and the results discussed in terms of the kinetics of immobilized enzymes. Loss in activity with respect to cadmium accumulation but not inorganic phosphate liberation was observed at acid pH and was attributed to the pH-dependent solubility of cadmium phosphate. Similarly high concentrations of chloride ions, and traces of cyanide inhibited cadmium uptake and this was attributed to the ability of these anions to complex heavy metals, especially the ability of CN/sup -/ to form complex anions with Cd/sup 2 +/. The data are discussed in terms of the known chemistry of chloride and cyanide-cadmium complexes and the relevance of these factors in the treatment of metal-containing liquid wastes is discussed. The cells immobilized in polyacrylamide provided a convenient small-scale laboratory model system. It was found that the Citrobacter sp. could be immobilized on glass supports with no chemical treatment or modification necessary. Such cells were also effective in metal accumulation and a prototype system more applicable to the treatment of metal-containing streams on a larger scale is described.

  16. Binary space partitioning trees and their uses

    NASA Technical Reports Server (NTRS)

    Bell, Bradley N.

    1989-01-01

    Binary Space Partitioning (BSP) trees have some qualities that make them useful in solving many graphics related problems. The purpose is to describe what a BSP tree is, and how it can be used to solve the problem of hidden surface removal, and constructive solid geometry. The BSP tree is based on the idea that a plane acting as a divider subdivides space into two parts with one being on the positive side and the other on the negative. A polygonal solid is then represented as the volume defined by the collective interior half spaces of the solid's bounding surfaces. The nature of how the tree is organized lends itself well for sorting polygons relative to an arbitrary point in 3 space. The speed at which the tree can be traversed for depth sorting is fast enough to provide hidden surface removal at interactive speeds. The fact that a BSP tree actually represents a polygonal solid as a bounded volume also makes it quite useful in performing the boolean operations used in constructive solid geometry. Due to the nature of the BSP tree, polygons can be classified as they are subdivided. The ability to classify polygons as they are subdivided can enhance the simplicity of implementing constructive solid geometry.

  17. Quantifying pretreatment degradation compounds in solution and accumulated by cells during solids and yeast recycling in the Rapid Bioconversion with Integrated recycling Technology process using AFEX™ corn stover.

    PubMed

    Sarks, Cory; Higbee, Alan; Piotrowski, Jeff; Xue, Saisi; Coon, Joshua J; Sato, Trey K; Jin, Mingjie; Balan, Venkatesh; Dale, Bruce E

    2016-04-01

    Effects of degradation products (low molecular weight compounds produced during pretreatment) on the microbes used in the RaBIT (Rapid Bioconversion with Integrated recycling Technology) process that reduces enzyme usage up to 40% by efficient enzyme recycling were studied. Chemical genomic profiling was performed, showing no yeast response differences in hydrolysates produced during RaBIT enzymatic hydrolysis. Concentrations of degradation products in solution were quantified after different enzymatic hydrolysis cycles and fermentation cycles. Intracellular degradation product concentrations were also measured following fermentation. Degradation product concentrations in hydrolysate did not change between RaBIT enzymatic hydrolysis cycles; the cell population retained its ability to oxidize/reduce (detoxify) aldehydes over five RaBIT fermentation cycles; and degradation products accumulated within or on the cells as RaBIT fermentation cycles increased. Synthetic hydrolysate was used to confirm that pretreatment degradation products are the sole cause of decreased xylose consumption during RaBIT fermentations.

  18. Chemical amplification based on fluid partitioning

    DOEpatents

    Anderson, Brian L.; Colston, Jr., Billy W.; Elkin, Chris

    2006-05-09

    A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

  19. Partitioning the Quaternary

    NASA Astrophysics Data System (ADS)

    Gibbard, Philip L.; Lewin, John

    2016-11-01

    We review the historical purposes and procedures for stratigraphical division and naming within the Quaternary, and summarize the current requirements for formal partitioning through the International Commission on Stratigraphy (ICS). A raft of new data and evidence has impacted traditional approaches: quasi-continuous records from ocean sediments and ice cores, new numerical dating techniques, and alternative macro-models, such as those provided through Sequence Stratigraphy and Earth-System Science. The practical usefulness of division remains, but there is now greater appreciation of complex Quaternary detail and the modelling of time continua, the latter also extending into the future. There are problems both of commission (what is done, but could be done better) and of omission (what gets left out) in partitioning the Quaternary. These include the challenge set by the use of unconformities as stage boundaries, how to deal with multiphase records in ocean and terrestrial sediments, what happened at the 'Early-Mid- (Middle) Pleistocene Transition', dealing with trends that cross phase boundaries, and the current controversial focus on how to subdivide the Holocene and formally define an 'Anthropocene'.

  20. EMPIRICAL MODELS OF PB AND CD PARTITIONING USING DATA FROM 13 SOILS, SEDIMENTS AND AQUIFER MATERIALS

    EPA Science Inventory

    Lead (Pb) and cadmium (Cd) are two of the most common toxicants found in contaminated environments. Because solubilization of these metallic elements from the solid phase can influence their fate, transport and bioavailability, the partitioning coefficient (Kd) for these metals ...

  1. Carbon partitioning in sugarcane (Saccharum species)

    PubMed Central

    Wang, Jianping; Nayak, Spurthi; Koch, Karen; Ming, Ray

    2013-01-01

    Focus has centered on C-partitioning in stems of sugarcane (Saccharum sp.) due to their high-sucrose accumulation features, relevance to other grasses, and rising economic value. Here we review how sugarcane balances between sucrose storage, respiration, and cell wall biosynthesis. The specific topics involve (1) accumulation of exceptionally high sucrose levels (up to over 500 mM), (2) a potential, turgor-sensitive system for partitioning sucrose between storage inside (cytosol and vacuole) and outside cells, (3) mechanisms to prevent back-flow of extracellular sucrose to xylem or phloem, (4) apparent roles of sucrose-P-synthase in fructose retrieval and sucrose re-synthesis, (5) enhanced importance of invertases, and (6) control of C-flux at key points in cell wall biosynthesis (UDP-glucose dehydrogenase) and respiration (ATP- and pyrophosphate-dependent phosphofructokinases). A combination of emerging technologies is rapidly enhancing our understanding of these points and our capacity to shift C-flux between sucrose, cell wall polymers, or other C-sinks. PMID:23785381

  2. Accumulate Repeat Accumulate Coded Modulation

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative coded modulation scheme called 'Accumulate Repeat Accumulate Coded Modulation' (ARA coded modulation). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes that are combined with high level modulation. Thus at the decoder belief propagation can be used for iterative decoding of ARA coded modulation on a graph, provided a demapper transforms the received in-phase and quadrature samples to reliability of the bits.

  3. Investigation of biogeochemical controls on the formation, uptake and accumulation of methylmercury in rice paddies in the vicinity of a coal-fired power plant and a municipal solid waste incinerator in Taiwan.

    PubMed

    Su, Yen-Bin; Chang, Wei-Chun; Hsi, Hsing-Cheng; Lin, Chu-Ching

    2016-07-01

    Recent studies have shown that rice consumption is another critical route of human exposure to methylmercury (MeHg), the most toxic and accumulative form of mercury (Hg) in the food web. Yet, the mechanisms that underlie the production and accumulation of MeHg in the paddy ecosystem are still poorly understood. In 2013 and 2014, we conducted field campaigns and laboratory experiments over a rice growing season to examine Hg and MeHg cycling, as well as associated biogeochemistry in a suite of paddies close to a municipal solid waste incinerator and a coal-fired power plant station in Taiwan. Concentrations of total Hg and MeHg in paddy soil and rice grain at both sites were low and found not to exceed the control standards for farmland soil and edible rice in Taiwan. However, seasonal variations of MeHg concentrations observed in pore water samples indicate that the in situ bioavailability of inorganic Hg and activity of Hg-methylating microbes in the rhizosphere increased from the early-season and peaked at the mid-season, presumably due to the anoxia created under flooded conditions and root exudation of organic compounds. The presence of Hg-methylators was also confirmed by the hgcA gene detected in all root soil samples. Subsequent methylation tests performed by incubating the root soil with inorganic Hg and an inhibitor or stimulant specific for certain microbes further revealed that sulfate-reducers might have been the principal Hg-methylting guild at the study sites. Interestingly, results of hydroponic experiments conducted by cultivating rice in a defined nutrient solution amended with fixed MeHg and varying levels of MeHg-binding ligands suggested that chemical speciation in soil pore water may play a key role in controlling MeHg accumulation in rice, and both passive and active transport pathways seem to take place in the uptake of MeHg in rice roots.

  4. Partitioning of main and side-chain units between different phases: a solid-state 13C NMR inversion-recovery cross-polarization study on a homogeneous, metallocene-based, ethylene-1-octene copolymer.

    PubMed

    Litvinov, Victor M; Mathot, Vincent B F

    2002-01-01

    13C NMR inversion-recovery cross-polarization experiments are used to study the phase structure and partitioning of main and side-chain groups in a homogeneous, metallocene-based, ethylene-1-octene copolymer. The results provide strong evidence for a three-phase model, i.e. a rigid, (imperfect) crystalline phase, which is mainly composed of long sequences of methylene carbon atoms of the main chain, a semi-rigid, amorphous interphase (also denoted as 'rigid amorphous'), which is enriched by chain segments bearing methylene and methine carbon atoms of the main chain, and a soft fraction of the amorphous phase (also denoted as 'mobile amorphous'), which is largely composed of side chains and short methylene sequences of the main chain.

  5. Partition Density Functional Theory

    NASA Astrophysics Data System (ADS)

    Wasserman, Adam

    2012-02-01

    Partition Density Functional Theory (PDFT) is a formally exact method for obtaining molecular properties from self-consistent calculations on isolated fragments [1,2]. For a given choice of fragmentation, PDFT outputs the (in principle exact) molecular energy and density, as well as fragment densities that sum to the correct molecular density. I describe our progress understanding the behavior of the fragment energies as a function of fragment occupations, derivative discontinuities, practical implementation, and applications of PDFT to small molecules. I also discuss implications for ground-state Density Functional Theory, such as the promise of PDFT to circumvent the delocalization error of approximate density functionals. [4pt] [1] M.H. Cohen and A. Wasserman, J. Phys. Chem. A, 111, 2229(2007).[0pt] [2] P. Elliott, K. Burke, M.H. Cohen, and A. Wasserman, Phys. Rev. A 82, 024501 (2010).

  6. Partitioning: splitting fact from fiction.

    PubMed

    Pike, Brian

    2012-05-01

    Many larger hospitals are sprawling complexes with endless corridors and rooms of varying purpose. While cleanliness and infection control are, understandably, leading considerations in any hospital building, fire safety also plays a crucial role. Here Brian Pike MBE, technical consultant at partitioning system designer and manufacturer, Komfort Workspace, looks at how current fire guidelines impact on the use of partitioning systems in hospital premises.

  7. Orientation and velocity dependence of the nonequilibrium partition coefficient

    NASA Technical Reports Server (NTRS)

    Beatty, K. M.; Jackson, K. A.

    1995-01-01

    Monte Carlo simulations based on a Spin-1 Ising Model for binary alloys have been used to investigate the non-equilibrium partition coefficient (k(sub neq)) as a function of solid-liquid interface velocity and orientation. In simulations of Si with a second component k(sub neq) is greater in the [111] direction than the [100] direction in agreement with experimental results reported by Azlz et al. The simulated partition coefficient scales with the square of the step velocity divided by the diffusion coefficient of the secondary component in the liquid.

  8. Partitioning ecosystems for sustainability.

    PubMed

    Murray, Martyn G

    2016-03-01

    Decline in the abundance of renewable natural resources (RNRs) coupled with increasing demands of an expanding human population will greatly intensify competition for Earth's natural resources during this century, yet curiously, analytical approaches to the management of productive ecosystems (ecological theory of wildlife harvesting, tragedy of the commons, green economics, and bioeconomics) give only peripheral attention to the driving influence of competition on resource exploitation. Here, I apply resource competition theory (RCT) to the exploitation of RNRs and derive four general policies in support of their sustainable and equitable use: (1) regulate resource extraction technology to avoid damage to the resource base; (2) increase efficiency of resource use and reduce waste at every step in the resource supply chain and distribution network; (3) partition ecosystems with the harvesting niche as the basic organizing principle for sustainable management of natural resources by multiple users; and (4) increase negative feedback between consumer and resource to bring about long-term sustainable use. A simple policy framework demonstrates how RCT integrates with other elements of sustainability science to better manage productive ecosystems. Several problem areas of RNR management are discussed in the light of RCT, including tragedy of the commons, overharvesting, resource collapse, bycatch, single species quotas, and simplification of ecosystems.

  9. Orientation-dependent impurity partitioning of colloidal crystals

    NASA Astrophysics Data System (ADS)

    Nozawa, Jun; Uda, Satoshi; Hu, Sumeng; Fujiwara, Kozo; Koizumi, Haruhiko

    2016-04-01

    Impurity partitioning during colloidal crystallization was investigated for grains with different orientations. Particles of various sizes were doped as impurities during the growth of colloidal polycrystals. The effective partition coefficient, keff, which is the impurity concentration in the solid (CS) divided by that in initial solution (CL), was measured for grains oriented in the [111] and [100] directions normal to the growth direction. The [111]-oriented grains were found to have a larger keff than [100]-oriented grains. This was analyzed by using the Thurmond and Struthers model. Though both [111]- and [100]-oriented grains were face centered cubic (fcc) structures, within several layers of crystals, the volume fraction of [111]-oriented grains was larger than that of [100]-oriented grains, yielding a larger driving force for nucleation, ΔGTr, and thus a larger equilibrium partition coefficient, k0, for [111]-oriented grains.

  10. The partitioning of trace elements during pulverized coal combustion

    NASA Astrophysics Data System (ADS)

    Seames, Wayne Stewart

    The environmental impact resulting from the release of trace elements during coal combustion is an important issue for the coal-fired electric utility industry. Trace elements exit the combustor by partitioning between the flue gas and the fly ash particles. A comprehensive study has been conducted to investigate the mechanisms governing the partitioning of trace elements during pulverized coal combustion. The behavior of seven trace elements (arsenic, selenium, antimony, cobalt, cesium, thorium, and cerium) in six pulverized coals were studied under commercially relevant conditions in a well-described laboratory combustion environment. The partitioning of trace elements is governed by the extent of volatilization during combustion, the form of occurrence in the flue gas, and the mechanisms controlling vapor-to-solid phase transformation to fly ash particle surfaces. The most common vapor-to-solid phase partitioning mechanism for semi-volatile trace elements is reaction with active fly ash surfaces. Trace elements that form oxy-anions upon volatilization (e.g. arsenic, selenium, antimony) will react with active calcium and iron cation fly ash surface sites. Trace elements that form simple oxides upon volatilization (e.g. cobalt, cesium) will react with active aluminum oxy-anion fly ash surface sites. The maximum combustion temperature affects the availability of active calcium and iron surface sites but not aluminum sites. Sulfur inhibits the reactivity of oxy-anions with iron surface sites. For coals with high sulfur contents (>1 wt % as SO 2), volatilized trace elements that form oxy-anions will partition by reaction with calcium surface sites if sufficient sites are available. For coals with low sulfur contents, volatilized trace elements that form oxy-anions, will partition by reaction with iron surface sites. Volatilized trace elements that form oxy-anions will not partition by reaction if the coal sulfur content is high and the calcium content is low (<3 wt

  11. Investigation of partitioning mechanism for volatile organic compounds in a multiphase system.

    PubMed

    Starokozhev, Elena; Sieg, Karsten; Fries, Elke; Püttmann, Willhelm

    2011-03-01

    Laboratory experiments were performed to investigate the partitioning behavior of a set of diverse volatile organic compounds (VOCs). After equilibration at a temperature of 25°C, the VOC concentrations were measured by headspace method in combination with gas chromatography/mass spectrometry (GC/MS). The obtained data were used to determine the partition coefficients (K(P)) of VOCs in a gas-liguid-solid system. The results have shown that the presence and nature of solid materials in the working solution control the air-water partitioning of dissolved VOCs. The air/solution partitioning of BTEX and C(9)-C(10) aldehydes was most affected in the presence of diesel soot. K(P) values decreased by a factor ranging from 1.5 for toluene to 3.0 for ethylbenzene. The addition of mineral dust in the working solution exhibited greater influence on the partitioning of short aldehydes. K(P) values decreased by a factor of 1.8. The experimental partition coefficients were used to develop a predictive model for partitioning of BTEX and n-aldehydes between air, water and solid phases.

  12. Metal separations using aqueous biphasic partitioning systems

    SciTech Connect

    Chaiko, D.J.; Zaslavsky, B.; Rollins, A.N.; Vojta, Y.; Gartelmann, J.; Mego, W.

    1996-05-01

    Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that the authors have studied are generated by combining an aqueous salt solution with an aqueous polymer solution. They have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. They have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this report they review the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation.

  13. Guidelines for Waste Accumulation Areas (WAAs)

    SciTech Connect

    Not Available

    1991-07-01

    The purpose of this document is to set conditions for establishing and maintaining areas for the accumulation of hazardous waste at LBL. Areas designed for accumulation of these wastes in quantities greater than 100 kg (220 lb) per month of solid waste or 55 gallons per month of liquid waste are called Waste Accumulation Areas (WAAs). Areas designed for accumulation of wastes in smaller amounts are called Satellite Accumulation Areas (SAAs). This document provides guidelines for employee and organizational responsibilities for WAAs; constructing a WAA; storing waste in a WAA; operating and maintaining a WAA, and responding to spills in a WAA. 4 figs.

  14. Temporal Partitioning on Multicore Platform

    NASA Astrophysics Data System (ADS)

    Mahmud Pathan, Ristat; Hashi, Feysal; Stenstrom, Per; Green, Lars-Goran; Hult, Torbjorn; Sandin, Patrik

    2014-08-01

    This paper addresses the problem of ensuring temporal partitioning according to the ARINC-653 standard for integrating multiple applications on the same multicore platform. To employ temporal partitioning, we propose the design and analysis of a hierarchical scheduling framework (HSF) for multicore platform. In HSF, each application has a server task, which is mapped to one of the physical cores of the multicore platform. The HSF framework is based on scheduling at two-levels: (i) a system-level scheduler for each core schedules the server tasks that are mapped to that core, and (ii) a task- level scheduler for each application schedules the tasks of the application. This paper presents the design and analysis of this two-level HSF that can be used to ensure temporal partitioning and meeting all the deadlines of each application tasks. The effectiveness of our technique is demonstrated using real-world space applications provided by RUAG Space Sweden AB.

  15. Carbon allocation and accumulation in conifers

    SciTech Connect

    Gower, S.T.; Isebrands, J.G.; Sheriff, D.W.

    1995-07-01

    Forests cover approximately 33% of the land surface of the earth, yet they are responsible for 65% of the annual carbon (C) accumulated by all terrestrial biomes. In general, total C content and net primary production rates are greater for forests than for other biomes, but C budgets differ greatly among forests. Despite several decades of research on forest C budgets, there is still an incomplete understanding of the factors controlling C allocation. Yet, if we are to understand how changing global events such as land use, climate change, atmospheric N deposition, ozone, and elevated atmospheric CO{sub 2} affect the global C budget, a mechanistic understanding of C assimilation, partitioning, and allocation is necessary. The objective of this chapter is to review the major factors that influence C allocation and accumulation in conifer trees and forests. In keeping with the theme of this book, we will focus primarily on evergreen conifers. However, even among evergreen conifers, leaf, canopy, and stand-level C and nutrient allocation patterns differ, often as a function of leaf development and longevity. The terminology related to C allocation literature is often inconsistent, confusing and inadequate for understanding and integrating past and current research. For example, terms often used synonymously to describe C flow or movement include translocation, transport, distribution, allocation, partitioning, apportionment, and biomass allocation. A common terminology is needed because different terms have different meanings to readers. In this paper we use C allocation, partitioning, and accumulation according to the definitions of Dickson and Isebrands (1993). Partitioning is the process of C flow into and among different chemical, storage, and transport pools. Allocation is the distribution of C to different plant parts within the plant (i.e., source to sink). Accumulation is the end product of the process of C allocation.

  16. Partition and generating function zeros in adsorbing self-avoiding walks

    NASA Astrophysics Data System (ADS)

    Janse van Rensburg, E. J.

    2017-03-01

    The Lee–Yang theory of adsorbing self-avoiding walks is presented. It is shown that Lee–Yang zeros of the generating function of this model asymptotically accumulate uniformly on a circle in the complex plane, and that Fisher zeros of the partition function distribute in the complex plane such that a positive fraction are located in annular regions centred at the origin. These results are examined in a numerical study of adsorbing self-avoiding walks in the square and cubic lattices. The numerical data are consistent with the rigorous results; for example, Lee–Yang zeros are found to accumulate on a circle in the complex plane and a positive fraction of partition function zeros appear to accumulate on a critical circle. The radial and angular distributions of partition function zeros are also examined and it is found to be consistent with the rigorous results.

  17. Partitioning Gas Tracer Technology for Measuring Water in Landfills

    NASA Astrophysics Data System (ADS)

    Briening, M. L.; Jakubowitch, A.; Imhoff, P. T.; Chiu, P. C.; Tittlebaum, M. E.

    2002-12-01

    Unstable landfills can result in significant environmental contamination and can become a risk to public health. To reduce this risk, water may be added to landfills to ensure that enough moisture exists for biodegradation of organic wastes. In this case risks associated with future breaks in the landfill cap are significantly reduced because organic material is degraded more rapidly. To modify moisture conditions and enhance biodegradation, leachate is typically collected from the bottom of the landfill and then recirculated near the top. It is difficult, though, to know how much leachate to add and where to add it to achieve uniform moisture conditions. This situation is exacerbated by the heterogeneous nature of landfill materials, which is known to cause short circuiting of infiltrating water, a process that has been virtually impossible to measure or model. Accurate methods for measuring the amount of water in landfills would be valuable aids for implementing leachate recirculation systems. Current methods for measuring water are inadequate, though, since they provide point measurements and are frequently affected by heterogeneity of the solid waste composition and solid waste compaction. The value of point measurements is significantly reduced in systems where water flows preferentially, such as in landfills. Here, spatially integrated measurements might be of greater value. In this research we are evaluating a promising technology, the partitioning gas tracer test, to measure the water saturation within landfills, the amount of free water in solid waste divided by the volume of the voids. The partitioning gas tracer test was recently developed by researchers working in the vadose zone. In this methodology two gas tracers are injected into a landfill. One tracer is non-reactive with landfill materials, while the second partitions into and out of free water trapped within the pore space of the solid waste. Chromatographic separation of the tracers occurs

  18. Understanding Partitive Division of Fractions.

    ERIC Educational Resources Information Center

    Ott, Jack M.; And Others

    1991-01-01

    Concrete experience should be a first step in the development of new abstract concepts and their symbolization. Presents concrete activities based on Hyde and Nelson's work with egg cartons and Steiner's work with money to develop students' understanding of partitive division when using fractions. (MDH)

  19. METAL PARTITIONING IN COMBUSTION PROCESSES

    EPA Science Inventory

    This article summarizes ongoing research efforts at the National Risk Management Research Laboratory of the U.S. Environmental Protection Agency examining [high temperature] metal behavior within combustion environments. The partitioning of non-volatile (Cr and Ni), semi-volatil...

  20. Some trees with partition dimension three

    NASA Astrophysics Data System (ADS)

    Fredlina, Ketut Queena; Baskoro, Edy Tri

    2016-02-01

    The concept of partition dimension of a graph was introduced by Chartrand, E. Salehi and P. Zhang (1998) [2]. Let G(V, E) be a connected graph. For S ⊆ V (G) and v ∈ V (G), define the distance d(v, S) from v to S is min{d(v, x)|x ∈ S}. Let Π be an ordered partition of V (G) and Π = {S1, S2, ..., Sk }. The representation r(v|Π) of vertex v with respect to Π is (d(v, S1), d(v, S2), ..., d(v, Sk)). If the representations of all vertices are distinct, then the partition Π is called a resolving partition of G. The partition dimension of G is the minimum k such that G has a resolving partition with k partition classes. In this paper, we characterize some classes of trees with partition dimension three, namely olive trees, weeds, and centipedes.

  1. Methodology for optimally sized centrifugal partition chromatography columns.

    PubMed

    Chollet, Sébastien; Marchal, Luc; Jérémy Meucci; Renault, Jean-Hugues; Legrand, Jack; Foucault, Alain

    2015-04-03

    Centrifugal Partition Chromatography (CPC) is a separation process based on the partitioning of solutes between two partially miscible liquid phases. There is no solid support for the stationary phase. The centrifugal acceleration is responsible for both stationary phase retention and mobile phase dispersion. CPC is thus a process based on liquid-liquid mass transfer. The separation efficiency is mainly influenced by the hydrodynamics of the phases in each cell of the column. Thanks to a visualization system, called "Visual CPC", it was observed that the mobile phase can flow through the stationary phase as a sheet, or a spray. Hydrodynamics, which directly governs the instrument efficiency, is directly affected during scale changes, and non-linear phenomena prevent the successful achievement of mastered geometrical scale changes. In this work, a methodology for CPC column sizing is proposed, based on the characterization of the efficiency of advanced cell shapes, taking into account the hydrodynamics. Knowledge about relationship between stationary phase volume, cell efficiency and separation resolution in CPC allowed calculating the optimum cell number for laboratory and industrial scale CPC application. The methodology is highlighted with results on five different geometries from 25 to 5000 mL, for two applications: the separation of alkylbenzene by partitioning with heptane/methanol/water biphasic system; and the separation of peptides by partitioning with n-butanol/acetic acid/water (4/1/5) biphasic system. With this approach, it is possible to predict the optimal CPC column length leading to highest productivity.

  2. Radionuclide partitioning across great lakes natural interfaces

    NASA Astrophysics Data System (ADS)

    Platford, R. F.; Joshi, S. R.

    1989-11-01

    Several water and surface microlayer samples from Lake St. Clair, the Niagara River, and the North Shore of Lake Ontario collected during 1983 1986 have been assayed for a variety of radionuclides. In addition, the foam accumulating in the pool just below Niagara Falls was also analyzed and found to be the most efficient aqueous phase collector of137Cs,210Pb, and226Ra. The order of radioisotope specific activities from highest to lowest is: Lake Ontario sediment, Niagara River suspended solids, Niagara River foam, surface microlayer water, and subsurface water. Radiological dose rates to the sediments from137Cs,226Ra, and228Th total about 5 mGy/y.

  3. Partitioning sparse rectangular matrices for parallel processing

    SciTech Connect

    Kolda, T.G.

    1998-05-01

    The authors are interested in partitioning sparse rectangular matrices for parallel processing. The partitioning problem has been well-studied in the square symmetric case, but the rectangular problem has received very little attention. They will formalize the rectangular matrix partitioning problem and discuss several methods for solving it. They will extend the spectral partitioning method for symmetric matrices to the rectangular case and compare this method to three new methods -- the alternating partitioning method and two hybrid methods. The hybrid methods will be shown to be best.

  4. Partition characteristics of polycyclic aromatic hydrocarbons on soils and sediments

    USGS Publications Warehouse

    Chiou, C.T.; Mcgroddy, S.E.; Kile, D.E.

    1998-01-01

    The partition behavior was determined for three polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene, phenanthrene, and pyrene, from water to a range of soil and sediment samples. The measured partition coefficients of the individual PAHs between soil/sediment organic matter (SOM) and water (i.e., K(oc) values) are relatively invariant either for the 'clean' (uncontaminated) soils or for the clean sediments; however, the mean K(oc) values on the sediments are about twice the values on the soils. This disparity is similar to the earlier observation for other nonpolar solutes and reflects the compositional differences between soil and sediment organic matters. No significant differences in K(oc) are observed between a clean coastal marine sediment and freshwater sediments. The coastal sediments that are significantly impacted by organic contaminants exhibit higher K(oc) values. At given K(ow) values (octanol-water), the PAHs exhibit much higher K(oc) values than other relatively nonpolar solutes (e.g., chlorinated hydrocarbons). This effect is shown to result from the enhanced partition of PAHs to SOM rather than from lower K(ow) values of PAHs at given supercooled liquid solute solubilities in water. The enhanced partition of PAHs over other nonpolar solutes in SOM provides an account of the markedly different correlations between log K(oc) and log K(ow) for PAHs and for other nonpolar solutes. The improved partition of PAHs in SOM stems apparently from the enhanced compatibility of their cohesive energy densities with those of the aromatic components in SOM. The approximate aromatic fraction in soil/sediment organic matter has been assessed by solid-state 13C-NMR spectroscopy.The partition behavior was determined for three polycyclic aromatic hydrocarbons (PAHs), i.e., naphthalene, phenanthrene, and pyrene, from water to a range of soil and sediment samples. The measured partition coefficients of the individual PAHs between soil/sediment organic matter (SOM

  5. Element Partitioning Constraints on Formation and Composition of the Earth's Core

    NASA Technical Reports Server (NTRS)

    Li, J.; Agee, C. B.; Fei, Y.

    1998-01-01

    Element partitioning study provides a number of constraints on the formation and composition of the core. First, partitioning of siderophile elements between the core and mantle should explain the "excess" siderophile elements in the mantle. Second, partitioning of light element(s) between the core and mantle should supply the core with the right amount of light element(s) to account for the density deficit in the core. Third, partitioning of light element(s) between the inner and outer core should be consistent with the observed difference in density deficits (relative to pure Fe) between these two reservoirs. In this study, high-pressure and high-temperature experiments have been conducted to investigate the pressure, temperature, and composition effects on partitioning of siderophile elements Ni and Co between core-forming Fe alloy and mantle silicate melt and minerals, partitioning of light elements S, O, and Si between core-forming Fe alloy and mantle silicate melt and minerals, and partitioning of light elements S and C between solid and liquid Fe. The implications of these results for mechanism of core formation and the composition of the core are discussed.

  6. Dual-phase reactor plant with partitioned isolation condenser

    DOEpatents

    Hui, Marvin M.

    1992-01-01

    A nuclear energy plant housing a boiling-water reactor utilizes an isolation condenser in which a single chamber is partitioned into a distributor plenum and a collector plenum. Steam accumulates in the distributor plenum and is conveyed to the collector plenum through an annular manifold that includes tubes extending through a condenser pool. The tubes provide for a transfer of heat from the steam, forming a condensate. The chamber has a disk-shaped base, a cylindrical sidewall, and a semispherical top. This geometry results in a compact design that exhibits significant performance and cost advantages over prior designs.

  7. Laser system with partitioned prism

    SciTech Connect

    Nettleton, J. E.; Barr, D. N.

    1985-03-26

    An array of optical frequency-sensitive elements such as diffraction gratings or interference filters are arranged in a row, and the optical path of the laser cavity can be directed to include one of these elements. A partitioned optical prism consisting of a triangular portion and one or more paralleogramatic portions are used to direct the path. Between the portions are piezoelectric elements which, when energized, expand to provide an air gap between the portions and to allow total reflection of an optical ray at the surface of the prism next to the gap.

  8. Partition coefficients for the trihalomethanes among blood, urine, water, milk and air.

    PubMed

    Batterman, Stuart; Zhang, Lian; Wang, Shugin; Franzblau, Alfred

    2002-02-04

    Chloroform, bromodichloromethane, chlorodibromomethane, and bromoform comprise the trihalomethanes, a group of widespread and mildly lipophilic compounds that result from water chlorination and other sources. Many animal studies show the chronic toxicity and carcinogenicity of these compounds, and recent work has demonstrated the importance of both ingestion and inhalation exposure pathways. This study presents partition coefficients describing the equilibrium among biological compartments (air, water, blood, milk, urine) for the four THMs based on results of headspace gas chromatographic analyses performed under equilibrium conditions and at 37 degrees C. The calculated partition coefficients ranged from 2.92 to 4.14 for blood/water, 1.54-2.85 for milk/blood, and 3.41-4.93 for blood/urine, with the lowest being chloroform and the highest being bromoform. Both human and cow milk were tested, with similar results. The available samples of human milk may not fully account for differences in lipid content and possibly other factors that affect estimates of partition coefficients. Simultaneous measurements of milk and blood in exposed individuals are suggested to confirm laboratory results. Partition coefficients are predicted using the octanol-air partition coefficient, also measured in this study, and the octanol-water partition coefficient. Results are similar to literature estimates for liquid/air partitioning of chloroform and chlorodibromomethane, but they differ from predictions based on hydrophobicity and lipid content. High correlations between the derived partitioned coefficients and the molecular structure (number of Br atoms) and physical properties (molecular weight and boiling point) are found for these analogous chemicals. In humans, THMs are both stored and metabolized with relatively rapid clearance rates. The derived partition coefficients can help to interpret results of biological monitoring and predict the potential for the accumulation and

  9. On some trees having partition dimension four

    NASA Astrophysics Data System (ADS)

    Ida Bagus Kade Puja Arimbawa, K.; Baskoro, Edy Tri

    2016-02-01

    In 1998, G. Chartrand, E. Salehi and P. Zhang introduced the notion of partition dimension of a graph. Since then, the study of this graph parameter has received much attention. A number of results have been obtained to know the values of partition dimensions of various classes of graphs. However, for some particular classes of graphs, finding of their partition dimensions is still not completely solved, for instances a class of general tree. In this paper, we study the properties of trees having partition dimension 4. In particular, we show that, for olive trees O(n), its partition dimension is equal to 4 if and only if 8 ≤ n ≤ 17. We also characterize all centipede trees having partition dimension 4.

  10. PARTITIONING OF GADOLINIUM IN THE CHEMICAL PROCESSING CELL

    SciTech Connect

    Reboul, S.; Best, D.; Stone, M.; Click, D.

    2011-04-27

    A combination of short-term beaker tests and longer-duration Sludge Receipt and Adjustment Tank (SRAT) simulations were performed to investigate the relative partitioning behaviors of gadolinium and iron under conditions applicable to the Chemical Processing Cell (CPC). The testing was performed utilizing non-radioactive simple Fe-Gd slurries, non-radioactive Sludge Batch 6 simulant slurries, and a radioactive real-waste slurry representative of Sludge Batch 7 material. The testing focused on the following range of conditions: (a) Fe:Gd ratios of 25-100; (b) pH values of 2-6; (c) acidification via addition of nitric, formic, and glycolic acids; (d) temperatures of {approx}93 C and {approx}22 C; and (e) oxalate concentrations of <100 mg/kg and {approx}10,000 mg/kg. The purpose of the testing was to provide data for assessing the potential use of gadolinium as a supplemental neutron poison when dispositioning excess plutonium. Understanding of the partitioning behavior of gadolinium in the CPC was the first step in assessing gadolinium's potential applicability. Significant fractions of gadolinium partitioned to the liquid-phase at pH values of 4.0 and below, regardless of the Fe:Gd ratio. In SRAT simulations targeting nitric and formic acid additions of 150% acid stoichiometry, the pH dropped to a minimum of 3.5-4.0, and the maximum fractions of gadolinium and iron partitioning to solution were both {approx}20%. In contrast, in a SRAT simulation utilizing a nitric and formic acid addition under atypical conditions (due to an anomalously low insoluble solids content), the pH dropped to a minimum of 3.7, and the maximum fractions of gadolinium and iron partitioning to solution were {approx}60% and {approx}70%, respectively. When glycolic acid was used in combination with nitric and formic acids at 100% acid stoichiometry, the pH dropped to a minimum of 3.6-4.0, and the maximum fractions of gadolinium and iron partitioning to solution were 60-80% and 3-5%, respectively

  11. Displaying multimedia environmental partitioning by triangular diagrams

    SciTech Connect

    Lee, S.C.; Mackay, D.

    1995-11-01

    It is suggested that equilateral triangular diagrams are a useful method of depicting the equilibrium partitioning of organic chemicals among the three primary environmental media of the atmosphere, the hydrosphere, and the organosphere (natural organic matter and biotic lipids and waxes). The technique is useful for grouping chemicals into classes according to their partitioning tendencies, for depicting the incremental effects of substituents such as alkyl groups and chlorine, and for showing how partitioning changes in response to changes in temperature.

  12. Chemical amplification based on fluid partitioning in an immiscible liquid

    DOEpatents

    Anderson, Brian L.; Colston, Bill W.; Elkin, Christopher J.

    2010-09-28

    A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

  13. The stringy instanton partition function

    NASA Astrophysics Data System (ADS)

    Bonelli, Giulio; Sciarappa, Antonio; Tanzini, Alessandro; Vasko, Petr

    2014-01-01

    We perform an exact computation of the gauged linear sigma model associated to a D1-D5 brane system on a resolved A 1 singularity. This is accomplished via supersymmetric localization on the blown-up two-sphere. We show that in the blow-down limit the partition function reduces to the Nekrasov partition function evaluating the equivariant volume of the instanton moduli space. For finite radius we obtain a tower of world-sheet instanton corrections, that we identify with the equivariant Gromov-Witten invariants of the ADHM moduli space. We show that these corrections can be encoded in a deformation of the Seiberg-Witten prepotential. From the mathematical viewpoint, the D1-D5 system under study displays a twofold nature: the D1-branes viewpoint captures the equivariant quantum cohomology of the ADHM instanton moduli space in the Givental formalism, and the D5-branes viewpoint is related to higher rank equivariant Donaldson-Thomas invariants of.

  14. Automatic analysis of D-partition

    NASA Astrophysics Data System (ADS)

    Bogaevskaya, V. G.

    2017-01-01

    The paper is dedicated to automatization of D-partition analysis. D-partition is one of the most common methods for determination of solution stability in systems with time-delayed feedback control and its dependency on values of control parameters. A transition from analytical form of D-partition to plain graph has been investigated. An algorithm of graph faces determination and calculation of count of characteristic equation roots with positive real part for appropriate area of D-partition has been developed. The algorithm keeps an information about analytical formulas for edges of faces. It allows to make further analytical research based on the results of computer analysis.

  15. Partitioning and diffusion of PBDEs through an HDPE geomembrane.

    PubMed

    Rowe, R Kerry; Saheli, Pooneh T; Rutter, Allison

    2016-09-01

    Polybrominated diphenyl ether (PBDE) has been measured in MSW landfill leachate and its migration through a modern landfill liner has not been investigated previously. To assure environmental protection, it is important to evaluate the efficacy of landfill liners for controlling the release of PBDE to the environment to a negligible level. The partitioning and diffusion of a commercial mixture of PBDEs (DE-71: predominantly containing six congeners) with respect to a high-density polyethylene (HDPE) geomembrane is examined. The results show that the partitioning coefficients of the six congeners in this mixture range from 700,000 to 7,500,000 and the diffusion coefficients range from 1.3 to 6.0×10(-15)m(2)/s depending on the congener. This combination of very high partitioning coefficients and very low diffusion coefficients suggest that a well constructed HDPE geomembrane liner will be an extremely effective barrier for PBDEs with respect to diffusion from a municipal solid waste landfill, as illustrated by an example. The results for pure diffusion scenario showed that the congeners investigated meet the guidelines by at least a factor of three for an effective geomembrane liner where diffusion is the controlling transport mechanism.

  16. Growth rate controlled barium partitioning in calcite and aragonite

    NASA Astrophysics Data System (ADS)

    Goetschl, Katja Elisabeth; Mavromatis, Vasileios; Baldermann, Andre; Purgstaller, Bettina; Dietzel, Martin

    2016-04-01

    The barium (Ba) content and the Ba/Ca molar ratios in biogenic and abiotic carbonates have been widely used from the scientific community as a geochemical proxy especially in marine and early diagenetic settings. The Ba content of carbonate minerals has been earlier associated to changes in oceanic circulation that may have been caused by upwelling, changes in weathering regimes and river-runoff as well as melt water discharge. The physicochemical controls of Ba ion incorporation in the two most abundant CaCO3 polymorphs found in Earth's surface environments, i.e. calcite and aragonite, have adequately been studied only for calcite. These earlier studies (i.e. [1]) suggest that at increasing growth rate, Ba partitioning in calcite is increasing as well. In contrast, to date the effect of growth rate on the partitioning of Ba in aragonite remains questionable, despite the fact that this mineral phase is the predominant carbonate-forming polymorph in shallow marine environments. To shed light on the mechanisms controlling Ba ion uptake in carbonates in this study we performed steady-state Ba co-precipitation experiments with calcite and aragonite at 25°C. The obtained results for the partitioning of Ba in calcite are in good agreement with those reported earlier by [1], whereas those for aragonite indicate a reduction of Ba partitioning at elevated aragonite growth rates, with the partitioning coefficient value between solid and fluid to be approaching the unity. This finding is good agreement with the formation of a solid solution in the aragonite-witherite system, owing to the isostructural crystallography of the two mineral phases. Moreover, our data set provides new insights that are required for reconstructing the evolution of the Ba content of pristine marine versus diagenetically altered carbonate minerals commonly occurring in marine subfloor settings, as the thermodynamically less stable aragonite will transform to calcite enriched in Ba, whilst affecting

  17. Relationship between carbohydrate partitioning and drought resistance in common bean.

    PubMed

    Cuellar-Ortiz, Sonia M; De La Paz Arrieta-Montiel, Maria; Acosta-Gallegos, Jorge; Covarrubias, Alejandra A

    2008-10-01

    Drought is a major yield constraint in common bean (Phaseolus vulgaris L.). Pulse-chase (14)C-labelling experiments were performed using Pinto Villa (drought resistant) and Canario 60 (drought sensitive) cultivars, grown under optimal irrigation and water-deficit conditions. Starch and the radioactive label incorporated into starch were measured in leaves and pods at different time points, between the initiation of pod development and the production of mature pods. The water-stress treatment induced a higher starch accumulation in the drought-resistant cultivar pods than in those of the drought-sensitive cultivar. This effect was more noticeable during the early stages of pod development. Consistently, a reduction of starch content occurred in the leaves of the drought-resistant cultivar during the grain-filling stage. Furthermore, a synchronized accumulation of sucrose was observed in immature pods of this cultivar. These data indicate that carbohydrate partitioning is affected by drought in common bean, and that the modulation of this partitioning towards seed filling has been a successful strategy in the development of drought-resistant cultivars. In addition, our results suggest that, in the drought-resistant cultivar, the efficient carbon mobilization towards the seeds in response to water limitation is favoured by a mechanism that implies a more effective sucrose transport.

  18. Characterization of partitioning behaviors of immunoglobulin G in polymer-salt aqueous two-phase systems.

    PubMed

    Chow, Yin Hui; Yap, Yee Jiun; Show, Pau Loke; Juan, Joon Ching; Anuar, Mohd Shamsul; Ng, Eng-Poh; Ooi, Chien-Wei; Ling, Tau Chuan

    2016-11-01

    The partitioning behavior of immunoglobulin G (IgG) in the aqueous two-phase system (ATPS) composed of poly(ethylene glycol) (PEG) and phosphate was studied. The parameters of ATPS exhibiting the pronounced effects on the partitioning behavior of IgG include phase composition, PEG molecular weight, and the addition of sodium chloride (NaCl). The accumulation of IgG at the interface of the ATPS increased drastically as the tie-line length (TLL) was increased. This trend was correlated with a linear relationship relating the natural logarithm of interfacial partition coefficient (ln G) to the difference of PEG concentration between the top phase and the bottom phase (Δ[PEG]), and a good fit was obtained. An attempt was made to correlate the natural logarithm of partition coefficient (ln K) to the presence of NaCl with the proposed linear relationship, ln K = α″ ln [Cl(-)] + β″. The proposed relationship, which serves as a better description of the underlying mechanics of the protein partitioning behavior in the polymer-salt ATPS, provides a good fit (r(2) > 0.95) for the data of IgG partitioning. An optimum recovery of 99.97% was achieved in an ATPS (pH 7.5) composed of 14.0% (w/w) PEG 1450, 12.5% (w/w) phosphate and 5.0% (w/w) NaCl.

  19. Disentangling event-scale hydrologic flow partitioning in mountains of the Korean Peninsula under extreme precipitation

    NASA Astrophysics Data System (ADS)

    Shope, Christopher L.

    2016-07-01

    Mountainous headwaters include a variety of spatial landscape units; however, the flow contribution from different hydrologic components is complex and often unclear. In addition to complex landscape controls, temporal meteorological drivers play an important role in the distribution between surface runoff and subsurface storage changes. This spatiotemporal variability in partitioning can influence catchment-wide flow accumulation and nutrient and sediment loading. We use a multi-year, multi-method analysis of stable isotopes, geochemical indicators, and discharge distributed throughout the Haean catchment in South Korea to identify temporal variability in hydrologic flow partitioning from surface runoff, springs, shallow interflow, and groundwater under monsoonal conditions. By combining a weighted, multi-method discharge approach, high frequency, synoptic, catchment-wide isotopic and geochemical sampling, and baseflow analysis, we characterize watershed-scale spatiotemporal hydrologic flow partitioning. Meteorological drivers are spatially variable throughout the catchment and temporally between individual events. Baseflow contributions in the high elevation, forested areas are up to 50%, while the majority of the catchment is approximately 20%. Our study builds on previously reported seasonality of isotopic signatures by quantifying trends in distributed event-based partitioning of isotopic tracers. We demonstrate that high frequency flow partitioning can accurately be determined in mountainous topography with high precipitation and that there is a need for multiple method characterizations. Our results further show the benefit of spatially distributed synoptic sampling for process understanding of hydrologic partitioning throughout the watersheds.

  20. Two-phase partitioning bioreactors in environmental biotechnology.

    PubMed

    Quijano, Guillermo; Hernandez, María; Thalasso, Frédéric; Muñoz, Raúl; Villaverde, Santiago

    2009-10-01

    Two-phase partitioning bioreactors (TPPBs) in environmental biotechnology are based on the addition of a non-aqueous phase (NAP) into a biological process in order to overcome both mass-transfer limitations from the gas to aqueous phase and pollutant-mediated inhibitions. Despite constituting a robust and reliable technology in terms of pollutant biodegradation rates and process stability in wastewater, soil, and gas treatment applications, this superior performance only applies for a restricted number of pollutants or contamination events. Severe limitations such as high energy requirements, high costs of some NAPs, foaming, or pollutant sequestration challenge the full-scale application of this technology. The introduction of solid NAPs into this research field has opened a promising pathway for the future development of TPPBs. Finally, this work reviews fundamental aspects of NAP selection and mass transfer and identifies the niches for future research: low energy-demand bioreactor designs, experimental determination of partial mass transfers, and solid NAP tailoring.

  1. Assimilate partitioning during reproductive growth

    SciTech Connect

    Finazzo, S.F.; Davenport, T.L.

    1987-04-01

    Leaves having various phyllotactic relationships to fruitlets were labeled for 1 hour with 10/sub r/Ci of /sup 14/CO/sub 2/. Fruitlets were also labeled. Fruitlets did fix /sup 14/CO/sub 2/. Translocation of radioactivity from the peel into the fruit occurred slowly and to a limited extent. No evidence of translocation out of the fruitlets was observed. Assimilate partitioning in avocado was strongly influenced by phyllotaxy. If a fruit and the labeled leaf had the same phyllotaxy then greater than 95% of the radiolabel was present in this fruit. When the fruit did not have the same phyllotaxy as the labeled leaf, the radiolabel distribution was skewed with 70% of the label going to a single adjacent position. Avocado fruitlets exhibit uniform labeling throughout a particular tissue. In avocado, assimilates preferentially move from leaves to fruits with the same phyllotaxy.

  2. MULTIVARIATE KERNEL PARTITION PROCESS MIXTURES

    PubMed Central

    Dunson, David B.

    2013-01-01

    Mixtures provide a useful approach for relaxing parametric assumptions. Discrete mixture models induce clusters, typically with the same cluster allocation for each parameter in multivariate cases. As a more flexible approach that facilitates sparse nonparametric modeling of multivariate random effects distributions, this article proposes a kernel partition process (KPP) in which the cluster allocation varies for different parameters. The KPP is shown to be the driving measure for a multivariate ordered Chinese restaurant process that induces a highly-flexible dependence structure in local clustering. This structure allows the relative locations of the random effects to inform the clustering process, with spatially-proximal random effects likely to be assigned the same cluster index. An exact block Gibbs sampler is developed for posterior computation, avoiding truncation of the infinite measure. The methods are applied to hormone curve data, and a dependent KPP is proposed for classification from functional predictors. PMID:24478563

  3. HPAM: Hirshfeld partitioned atomic multipoles

    NASA Astrophysics Data System (ADS)

    Elking, Dennis M.; Perera, Lalith; Pedersen, Lee G.

    2012-02-01

    An implementation of the Hirshfeld (HD) and Hirshfeld-Iterated (HD-I) atomic charge density partitioning schemes is described. Atomic charges and atomic multipoles are calculated from the HD and HD-I atomic charge densities for arbitrary atomic multipole rank l on molecules of arbitrary shape and size. The HD and HD-I atomic charges/multipoles are tested by comparing molecular multipole moments and the electrostatic potential (ESP) surrounding a molecule with their reference ab initio values. In general, the HD-I atomic charges/multipoles are found to better reproduce ab initio electrostatic properties over HD atomic charges/multipoles. A systematic increase in precision for reproducing ab initio electrostatic properties is demonstrated by increasing the atomic multipole rank from l=0 (atomic charges) to l=4 (atomic hexadecapoles). Both HD and HD-I atomic multipoles up to rank l are shown to exactly reproduce ab initio molecular multipole moments of rank L for L⩽l. In addition, molecular dipole moments calculated by HD, HD-I, and ChelpG atomic charges only ( l=0) are compared with reference ab initio values. Significant errors in reproducing ab initio molecular dipole moments are found if only HD or HD-I atomic charges used. Program summaryProgram title: HPAM Catalogue identifier: AEKP_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKP_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License v2 No. of lines in distributed program, including test data, etc.: 500 809 No. of bytes in distributed program, including test data, etc.: 13 424 494 Distribution format: tar.gz Programming language: C Computer: Any Operating system: Linux RAM: Typically, a few hundred megabytes Classification: 16.13 External routines: The program requires 'formatted checkpoint' files obtained from the Gaussian 03 or Gaussian 09 quantum chemistry program. Nature of problem: An ab initio

  4. Trace element transformations and partitioning during the roasting of pyrite ores in the sulfuric acid industry.

    PubMed

    Yang, Chunxia; Chen, Yongheng; Peng, Ping'an; Li, Chao; Chang, Xiangyang; Wu, Yingjuan

    2009-08-15

    Total concentrations combined with chemical partitioning of trace elements (Cd, Co, Cr, Mn, Ni, Pb, Tl, and Zn) in raw pyrite ore and solid roasting wastes were investigated in order to elucidate their transformations and partitioning during the roasting of raw pyrite ores in sulfuric acid production. In order to better understand the behavior of these elements during roasting, mineral transformations accompanying roasting were also investigated by using microscopy. Results indicated that the mode of occurrence of trace elements in raw pyrite ore and the thermostability of trace element-bearing species formed during roasting played major roles in the transformations of the selected trace elements. Silicate- and amorphous iron (hydr)oxide-bound elements (Cr and Pb) were stable and mainly retained in their original phases. However, acid-exchangeable and sulfide-bound elements tended to transform into other forms via different pathways: elements that tend to form low thermostable species (Cd, Pb and Tl) were significantly vaporized, whereas elements that tend to form high thermostable species (Co, Mn and Ni) mainly reacted with iron oxides or silicates, which then remained in the solid residues. The volatility of trace elements during the roasting has a significant effect on their subsequent partitioning in roasting wastes. Nonvolatile element (Co, Cr, Mn, and Ni) partitioning was determined by settling of the particulate in which they are bound, whereas the partitioning of (semi)volatile elements (Cd, Pb, Tl, and Zn) was controlled by the adsorption of their gaseous species on the particulate.

  5. [On the partition of acupuncture academic schools].

    PubMed

    Yang, Pengyan; Luo, Xi; Xia, Youbing

    2016-05-01

    Nowadays extensive attention has been paid on the research of acupuncture academic schools, however, a widely accepted method of partition of acupuncture academic schools is still in need. In this paper, the methods of partition of acupuncture academic schools in the history have been arranged, and three typical methods of"partition of five schools" "partition of eighteen schools" and "two-stage based partition" are summarized. After adeep analysis on the disadvantages and advantages of these three methods, a new method of partition of acupuncture academic schools that is called "three-stage based partition" is proposed. In this method, after the overall acupuncture academic schools are divided into an ancient stage, a modern stage and a contemporary stage, each schoolis divided into its sub-school category. It is believed that this method of partition can remedy the weaknesses ofcurrent methods, but also explore a new model of inheritance and development under a different aspect through thedifferentiation and interaction of acupuncture academic schools at three stages.

  6. Continuous Graph Partitioning for Camera Network Surveillance

    DTIC Science & Technology

    2012-07-23

    Symmetric Gossip partitioning algorithm The distributed algorithm presented in this section assumes a symmetric gossip -type communication protocol . In... gossip communication. We prove convergence of all these algorithms, and we analyze their performance in a simulation study. 2 Continuous Partitions of...section assumes an asymmetric broadcast communication protocol . In particular, at each iteration only one camera updates its state by using local

  7. Building Ecology and Partition Design. Technical Bulletin.

    ERIC Educational Resources Information Center

    Maryland State Dept. of Education, Baltimore.

    This bulletin is intended as a resource for school system facility planners and architects who design schools. Ways in which decision makers can incorporate environmental concerns in the design of school buildings are detailed. Focus is on the design of interior partition systems. Partition systems in schools serve several purposes; they define…

  8. Graph Partitioning Models for Parallel Computing

    SciTech Connect

    Hendrickson, B.; Kolda, T.G.

    1999-03-02

    Calculations can naturally be described as graphs in which vertices represent computation and edges reflect data dependencies. By partitioning the vertices of a graph, the calculation can be divided among processors of a parallel computer. However, the standard methodology for graph partitioning minimizes the wrong metric and lacks expressibility. We survey several recently proposed alternatives and discuss their relative merits.

  9. Modeling kinetic partitioning of secondary organic aerosol and size distribution dynamics: representing effects of volatility, phase state, and particle-phase reaction

    SciTech Connect

    Zaveri, Rahul A.; Easter, Richard C.; Shilling, John E.; Seinfeld, J. H.

    2014-05-27

    Evidence is mounting that the majority of the climatically active aerosols are produced through the growth of smaller particles via secondary organic aerosol (SOA) formation from gas-to-particle conversion of anthropogenic and biogenic volatile organic compounds (VOCs). The timescale of SOA partitioning and the associated size distribution dynamics are expected to depend on the gas-phase oxidation of the precursor VOCs and their products, volatility of these organic solutes, composition and phase state of the pre-existing particles, and diffusivity and reactivity of the solute within the particle phase. This paper describes a new framework for modeling kinetic gas-particle partitioning of SOA, with an analytical treatment for the diffusion-reaction process within the particle phase. The formulation is amenable for eventual use in regional and global climate models, although it currently awaits implementation of the actual particle-phase reactions that are important for SOA formation. In the present work, the model is applied to investigate the competitive growth dynamics of the Aitken and accumulation mode particles while the Kelvin effect and coagulation are neglected for simplicity. The timescale of SOA partitioning and evolution of number and composition size distributions are evaluated for a range of solute volatilities (C*), particle-phase bulk diffusivities (Db), and particle-phase reactivity, as exemplified by a pseudo-first-order rate constant (kc). Results show that irreversible condensation of non-volatile organic vapors (equivalent to ) produces significant narrowing of the size distribution. At the other extreme, non-reactive partitioning of semi-volatile organic vapors is volume-controlled in which the final (equilibrium) size distribution simply shifts to the right on the diameter axis while its shape remains unchanged. However, appreciable narrowing of the size distribution may occur when the pre-existing particles are highly viscous semi-solids such

  10. Partition behaviour of alkylphenols in crude oil/brine systems under subsurface conditions

    NASA Astrophysics Data System (ADS)

    Bennett, B.; Larter, S. R.

    1997-10-01

    Partition of organic solutes between oils and water in the subsurface is an important geochemical process occurring during petroleum migration and reservoiring, during water washing, and during petroleum production. Currently no data exists on the quantitative aspects of the partition process at subsurface conditions for solutes such as phenols and aromatic hydrocarbons which are major components of both oils and waters. We have constructed an equilibration device for oils and waters based on flow injection analysis principles to measure partition coefficients of alkylphenols in crude oil/brine systems under reservoir conditions. Concentrations of C 0C 2 alkylphenols in waters and solid phase extracts of crude oils produced in the device were determined by reverse phase high performance liquid chromatography with electrochemical detection (RP-HPLC-ED), partition coefficients being measured as a function of pressure (25-340 bar), temperature (25-150°C), and water salinity (0-100,000 mg/L sodium chloride) for a variety of oils. Partition coefficients for all compounds decreased with increasing temperature, increased with water salinity and crude oil bulk NSO content, and showed little change with varying pressure. These laboratory measurements, determined under conditions close to those typically encountered in petroleum reservoirs, suggest temperature, water salinity, and crude oil bulk NSO content will have important influence on oil-water partition processes in the subsurface during migration and water washing.

  11. Prediction of partition coefficients of organic compounds between SPME/PDMS and aqueous solution.

    PubMed

    Chao, Keh-Ping; Lu, Yu-Ting; Yang, Hsiu-Wen

    2014-02-14

    Polydimethylsiloxane (PDMS) is commonly used as the coated polymer in the solid phase microextraction (SPME) technique. In this study, the partition coefficients of organic compounds between SPME/PDMS and the aqueous solution were compiled from the literature sources. The correlation analysis for partition coefficients was conducted to interpret the effect of their physicochemical properties and descriptors on the partitioning process. The PDMS-water partition coefficients were significantly correlated to the polarizability of organic compounds (r = 0.977, p < 0.05). An empirical model, consisting of the polarizability, the molecular connectivity index, and an indicator variable, was developed to appropriately predict the partition coefficients of 61 organic compounds for the training set. The predictive ability of the empirical model was demonstrated by using it on a test set of 26 chemicals not included in the training set. The empirical model, applying the straightforward calculated molecular descriptors, for estimating the PDMS-water partition coefficient will contribute to the practical applications of the SPME technique.

  12. Purification of biomaterials by phase partitioning

    NASA Technical Reports Server (NTRS)

    Harris, J. M.

    1984-01-01

    A technique which is particularly suited to microgravity environments and which is potentially more powerful than electrophoresis is phase partitioning. Phase partitioning is purification by partitioning between the two immiscible aqueous layers formed by solution of the polymers poly(ethylene glycol) and dextran in water. This technique proved to be very useful for separations in one-g but is limited for cells because the cells are more dense than the phase solutions thus tend to sediment to the bottom of the container before reaching equilibrium with the preferred phase. There are three phases to work in this area: synthesis of new polymers for affinity phase partitioning; development of automated apparatus for ground-based separations; and design of apparatus for performing simple phase partitioning space experiments, including examination of mechanisms for separating phases in the absence of gravity.

  13. Cell partition in two phase polymer systems

    NASA Technical Reports Server (NTRS)

    Brooks, D. E.

    1979-01-01

    Aqueous phase-separated polymer solutions can be used as support media for the partition of biological macromolecules, organelles and cells. Cell separations using the technique have proven to be extremely sensitive to cell surface properties but application of the systems are limited to cells or aggregates which do not significantly while the phases are settling. Partition in zero g in principle removes this limitation but an external driving force must be applied to induce the phases to separate since their density difference disappears. We have recently shown that an applied electric field can supply the necessary driving force. We are proposing to utilize the NASA FES to study field-driven phase separation and cell partition on the ground and in zero g to help define the separation/partition process, with the ultimate goal being to develop partition as a zero g cell separation technique.

  14. Parallel hypergraph partitioning for scientific computing.

    SciTech Connect

    Heaphy, Robert; Devine, Karen Dragon; Catalyurek, Umit; Bisseling, Robert; Hendrickson, Bruce Alan; Boman, Erik Gunnar

    2005-07-01

    Graph partitioning is often used for load balancing in parallel computing, but it is known that hypergraph partitioning has several advantages. First, hypergraphs more accurately model communication volume, and second, they are more expressive and can better represent nonsymmetric problems. Hypergraph partitioning is particularly suited to parallel sparse matrix-vector multiplication, a common kernel in scientific computing. We present a parallel software package for hypergraph (and sparse matrix) partitioning developed at Sandia National Labs. The algorithm is a variation on multilevel partitioning. Our parallel implementation is novel in that it uses a two-dimensional data distribution among processors. We present empirical results that show our parallel implementation achieves good speedup on several large problems (up to 33 million nonzeros) with up to 64 processors on a Linux cluster.

  15. Efficient multiple-way graph partitioning algorithms

    SciTech Connect

    Dasdan, A.; Aykanat, C.

    1995-12-01

    Graph partitioning deals with evenly dividing a graph into two or more parts such that the total weight of edges interconnecting these parts, i.e., cutsize, is minimized. Graph partitioning has important applications in VLSI layout, mapping, and sparse Gaussian elimination. Since graph partitioning problem is NP-hard, we should resort to polynomial-time algorithms to obtain a good solution, or hopefully a near-optimal solution. Kernighan-Lin (KL) propsoed a 2-way partitioning algorithms. Fiduccia-Mattheyses (FM) introduced a faster version of KL algorithm. Sanchis (FMS) generalized FM algorithm to a multiple-way partitioning algorithm. Simulated Annealing (SA) is one of the most successful approaches that are not KL-based.

  16. Recovery of small bioparticles by interfacial partitioning.

    PubMed

    Jauregi, P; Hoeben, M A; van der Lans, R G J M; Kwant, G; van der Wielen, L A M

    2002-05-20

    In this article, a qualitative study of the recovery of small bioparticles by interfacial partitioning in liquid-liquid biphasic systems is presented. A range of crystallised biomolecules with varying polarities have been chosen such as glycine, phenylglycine and ampicillin. Liquid-liquid biphasic systems in a range of polarity differences were selected such as an aqueous two-phase system (ATPS), water-butanol and water-hexanol. The results indicate that interfacial partitioning of crystals occurs even when their density exceeds that of the individual liquid phases. Yet, not all crystals partition to the same extent to the interface to form a stable and thick interphase layer. This indicates some degree of selectivity. From the analysis of these results in relation to the physicochemical properties of the crystals and the liquid phases, a hypothetical mechanism for the interfacial partitioning is deduced. Overall these results support the potential of interfacial partitioning as a large scale separation technology.

  17. Partition coefficients of organic compounds in new imidazolium based ionic liquids using inverse gas chromatography.

    PubMed

    Revelli, Anne-Laure; Mutelet, Fabrice; Jaubert, Jean-Noël

    2009-06-05

    Partition coefficients of organic compounds in four ionic liquids: 1-ethanol-3-methylimidazolium tetrafluoroborate, 1-ethanol-3-methylimidazolium hexafluorophosphate, 1,3-dimethylimidazolium dimethylphosphate and 1-ethyl-3-methylimidazolium diethylphosphate were measured using inverse gas chromatography from 303.3 to 332.55K. The influence of gas-liquid and gas-solid interfacial adsorption of different solutes on ionic liquids was also studied. Most of the polar solutes were retained largely by partition while light hydrocarbons were retained predominantly by interfacial adsorption on the ionic liquids studied in this work. The solvation characteristics of the ionic liquids were evaluated using the Abraham solvation parameter model.

  18. Partitioned Bayesian analyses, partition choice, and the phylogenetic relationships of scincid lizards.

    PubMed

    Brandley, Matthew C; Schmitz, Andreas; Reeder, Tod W

    2005-06-01

    Partitioned Bayesian analyses of approximately 2.2 kb of nucleotide sequence data (mtDNA) were used to elucidate phylogenetic relationships among 30 scincid lizard genera. Few partitioned Bayesian analyses exist in the literature, resulting in a lack of methods to determine the appropriate number of and identity of partitions. Thus, a criterion, based on the Bayes factor, for selecting among competing partitioning strategies is proposed and tested. Improvements in both mean -lnL and estimated posterior probabilities were observed when specific models and parameter estimates were assumed for partitions of the total data set. This result is expected given that the 95% credible intervals of model parameter estimates for numerous partitions do not overlap and it reveals that different data partitions may evolve quite differently. We further demonstrate that how one partitions the data (by gene, codon position, etc.) is shown to be a greater concern than simply the overall number of partitions. Using the criterion of the 2 ln Bayes factor > 10, the phylogenetic analysis employing the largest number of partitions was decisively better than all other strategies. Strategies that partitioned the ND1 gene by codon position performed better than other partition strategies, regardless of the overall number of partitions. Scincidae, Acontinae, Lygosominae, east Asian and North American "Eumeces" + Neoseps; North African Eumeces, Scincus, and Scincopus, and a large group primarily from sub-Saharan Africa, Madagascar, and neighboring islands are monophyletic. Feylinia, a limbless group of previously uncertain relationships, is nested within a "scincine" clade from sub-Saharan Africa. We reject the hypothesis that the nearly limbless dibamids are derived from within the Scincidae, but cannot reject the hypothesis that they represent the sister taxon to skinks. Amphiglossus, Chalcides, the acontines Acontias and Typhlosaurus, and Scincinae are paraphyletic. The globally widespread

  19. REE Partitioning in Lunar Minerals

    NASA Technical Reports Server (NTRS)

    Rapp, J. F.; Lapen, T. J.; Draper, D. S.

    2015-01-01

    Rare earth elements (REE) are an extremely useful tool in modeling lunar magmatic processes. Here we present the first experimentally derived plagioclase/melt partition coefficients in lunar compositions covering the entire suite of REE. Positive europium anomalies are ubiquitous in the plagioclase-rich rocks of the lunar highlands, and complementary negative Eu anomalies are found in most lunar basalts. These features are taken as evidence of a large-scale differentiation event, with crystallization of a global-scale lunar magma ocean (LMO) resulting in a plagioclase flotation crust and a mafic lunar interior from which mare basalts were subsequently derived. However, the extent of the Eu anomaly in lunar rocks is variable. Fagan and Neal [1] reported highly anorthitic plagioclase grains in lunar impact melt rock 60635,19 that displayed negative Eu anomalies as well as the more usual positive anomalies. Indeed some grains in the sample are reported to display both positive and negative anomalies. Judging from cathodoluminescence images, these anomalies do not appear to be associated with crystal overgrowths or zones.

  20. Spectral partitioning in diffraction tomography

    SciTech Connect

    Lehman, S K; Chambers, D H; Candy, J V

    1999-06-14

    The scattering mechanism of diffraction tomography is described by the integral form of the Helmholtz equation. The goal of diffraction tomography is to invert this equation in order to reconstruct the object function from the measured scattered fields. During the forward propagation process, the spatial spectrum of the object under investigation is ''smeared,'' by a convolution in the spectral domain, across the propagating and evanescent regions of the received field. Hence, care must be taken in performing the reconstruction, as the object's spectral information has been moved into regions where it may be considered to be noise rather than useful information. This will reduce the quality and resolution of the reconstruction. We show haw the object's spectrum can be partitioned into resolvable and non-resolvable parts based upon the cutoff between the propagating and evanescent fields. Operating under the Born approximation, we develop a beam-forming on transmit approach to direct the energy into either the propagating or evanescent parts of the spectrum. In this manner, we may individually interrogate the propagating and evanescent regions of the object spectrum.

  1. Partitioning of regular computation on multiprocessor systems

    NASA Technical Reports Server (NTRS)

    Lee, Fung Fung

    1988-01-01

    Problem partitioning of regular computation over two dimensional meshes on multiprocessor systems is examined. The regular computation model considered involves repetitive evaluation of values at each mesh point with local communication. The computational workload and the communication pattern are the same at each mesh point. The regular computation model arises in numerical solutions of partial differential equations and simulations of cellular automata. Given a communication pattern, a systematic way to generate a family of partitions is presented. The influence of various partitioning schemes on performance is compared on the basis of computation to communication ratio.

  2. Partitioning of regular computation on multiprocessor systems

    NASA Technical Reports Server (NTRS)

    Lee, Fung F.

    1990-01-01

    Problem partitioning of regular computation over two dimensional meshes on multiprocessor systems is examined. The regular computation model considered involves repetitive evaluation of values at each mesh point with local communication. The computational workload and the communication pattern are the same at each mesh point. The regular computation model arises in numerical solutions of partial differential equations and simulations of cellular automata. Given a communication pattern, a systematic way to generate a family of partitions is presented. The influence of various partitioning schemes on performance is compared on the basis of computation to communication ratio.

  3. Partitioning of regular computation on multiprocessor systems

    SciTech Connect

    Lee, F. . Computer Systems Lab.)

    1990-07-01

    Problem partitioning of regular computation over two-dimensional meshes on multiprocessor systems is examined. The regular computation model considered involves repetitive evaluation of values at each mesh point with local communication. The computational workload and the communication pattern are the same at each mesh point. The regular computation model arises in numerical solutions of partial differential equations and simulations of cellular automata. Given a communication pattern, a systematic way to generate a family of partitions is presented. The influence of various partitioning schemes on performance is compared on the basis of computation to communication ratio.

  4. Evaluation of log K{sub ow} and tissue lipid content as predictors of chemical partitioning to fish tissues

    SciTech Connect

    Bertelsen, S.L.; Gallinat, C.A.; Elonen, C.M.; Hoffman, A.D.; Nichols, J.W.

    1998-08-01

    In vitro equilibrium chemical partition coefficients were determined for six chemicals in selected tissues from four species of fish. Log-transformed values were then regressed in stepwise fashion against chemical log octanol/water partition coefficient (K{sub ow}) and the log of tissue lipid content to derive a series of linear one- and two-variable models. Equations derived for fat indicate that n-octanol is a good surrogate for nonpolar lipid in the range of chemical log K{sub ow} tested (1.46 < log K{sub ow} < 4.04). These equations also support the conclusion that previously developed K{sub ow}-bioconcentration factor relationships are largely a reflection of chemical accumulation in fat. Fitted slope and intercept terms for lean tissues differed from those expected from chemical partitioning to lipid only and were instead consistent with the suggestion that partitioning to nonlipid-nonwater cellular constituents contributes substantially to chemical accumulation. A general equation is presented for prediction of tissue/water and blood/water partitioning from chemical log K{sub ow} and tissue (or blood) lipid content. It is suggested, however, that tissue- and blood-specific equations be used to estimate the tissue/blood partitioning relationships needed for kinetic modeling efforts.

  5. The accumulation and structure of comets

    NASA Technical Reports Server (NTRS)

    Donn, Bertram

    1991-01-01

    The paper reviews evidence for the accumulation of the terrestrial planets and comets from solid grains, with emphasis on the various proposals for the formation of cometary nuclei. With three exceptions, all hypotheses conclude or imply that a single compact object forms. Several hypotheses start with Goldreich-Ward-type gravitational instabilities. The collapse for this case also occurs at low velocities in the cm/s to m/s range. Experiment and theory show that under these conditions, low-density, filamentary clusters form that are fractal aggregates with a fractal dimension approximately equal to 2. In order to form cometary nuclei, the initial temperature must be about 50 K and not undergo a significant temperature rise during the accumulation process. The calculations show that accumulation will occur at low temperatures. Models of cometary nuclei are reviewed, and a simple model of the structure that results fom the accumulation of fluffy aggregates is described.

  6. Merging Groups to Maximize Object Partition Comparison.

    ERIC Educational Resources Information Center

    Klastorin, T. D.

    1980-01-01

    The problem of objectively comparing two independently determined partitions of N objects or variables is discussed. A similarity measure based on the simple matching coefficient is defined and related to previously suggested measures. (Author/JKS)

  7. Cell Partition in Two Polymer Aqueous Phases

    NASA Technical Reports Server (NTRS)

    Harris, J. M.

    1985-01-01

    Partition of biological cells in two phase aqueous polymer systems is recognized as a powerful separation technique which is limited by gravity. The synthesis of new, selective polymer ligand conjugates to be used in affinity partition separations is of interest. The two most commonly used polymers in two phase partitioning are dextran and polyethylene glycol. A thorough review of the chemistry of these polymers was begun, particularly in the area of protein attachment. Preliminary studies indicate the importance in affinity partitioning of minimizing gravity induced randomizing forces in the phase separation process. The PEG-protein conjugates that were prepared appear to be ideally suited for achieving high quality purifications in a microgravity environment. An interesting spin-off of this synthetic work was the observation of catalytic activity for certain of our polymer derivatives.

  8. Synthesis on evaporation partitioning using stable isotopes

    NASA Astrophysics Data System (ADS)

    Coenders-Gerrits, Miriam; Bogaard, Thom; Wenninger, Jochen; Jonson Sutanto, Samuel

    2015-04-01

    Partitioning of evaporation into productive (transpiration) and non-productive evaporation (interception, soil evaporation) is of highest importance for water management practices, irrigation scheme design, and climate modeling. Despite this urge, the magnitude of the ratio of transpiration over total evaporation is still under debate and poorly understood due to measuring difficulties. However, with the current development in isotope measuring devices, new opportunities arise to untangle the partitioning of evaporation. In this paper we synthesize the opportunities and limitations using stable water isotopes in evaporation partitioning. We will analyze a set of field as well as laboratory studies to demonstrate the different evaporation components for various climate and vegetation conditions using stable isotopes 18O/16O and 2H/1H. Experimental data on evaporation partitioning of crops, grass, shrubs and trees are presented and we will discuss the specific experimental set-ups and data collection methods. The paper will be a synthesis of these studies.

  9. Reducing variance in batch partitioning measurements

    SciTech Connect

    Mariner, Paul E.

    2010-08-11

    The partitioning experiment is commonly performed with little or no attention to reducing measurement variance. Batch test procedures such as those used to measure K{sub d} values (e.g., ASTM D 4646 and EPA402 -R-99-004A) do not explain how to evaluate measurement uncertainty nor how to minimize measurement variance. In fact, ASTM D 4646 prescribes a sorbent:water ratio that prevents variance minimization. Consequently, the variance of a set of partitioning measurements can be extreme and even absurd. Such data sets, which are commonplace, hamper probabilistic modeling efforts. An error-savvy design requires adjustment of the solution:sorbent ratio so that approximately half of the sorbate partitions to the sorbent. Results of Monte Carlo simulations indicate that this simple step can markedly improve the precision and statistical characterization of partitioning uncertainty.

  10. Connections between groundwater flow and transpiration partitioning

    NASA Astrophysics Data System (ADS)

    Maxwell, Reed M.; Condon, Laura E.

    2016-07-01

    Understanding freshwater fluxes at continental scales will help us better predict hydrologic response and manage our terrestrial water resources. The partitioning of evapotranspiration into bare soil evaporation and plant transpiration remains a key uncertainty in the terrestrial water balance. We used integrated hydrologic simulations that couple vegetation and land-energy processes with surface and subsurface hydrology to study transpiration partitioning at the continental scale. Both latent heat flux and partitioning are connected to water table depth, and including lateral groundwater flow in the model increases transpiration partitioning from 47 ± 13 to 62 ± 12%. This suggests that lateral groundwater flow, which is generally simplified or excluded in Earth system models, may provide a missing link for reconciling observations and global models of terrestrial water fluxes.

  11. Connections between groundwater flow and transpiration partitioning.

    PubMed

    Maxwell, Reed M; Condon, Laura E

    2016-07-22

    Understanding freshwater fluxes at continental scales will help us better predict hydrologic response and manage our terrestrial water resources. The partitioning of evapotranspiration into bare soil evaporation and plant transpiration remains a key uncertainty in the terrestrial water balance. We used integrated hydrologic simulations that couple vegetation and land-energy processes with surface and subsurface hydrology to study transpiration partitioning at the continental scale. Both latent heat flux and partitioning are connected to water table depth, and including lateral groundwater flow in the model increases transpiration partitioning from 47 ± 13 to 62 ± 12%. This suggests that lateral groundwater flow, which is generally simplified or excluded in Earth system models, may provide a missing link for reconciling observations and global models of terrestrial water fluxes.

  12. Tonoplast Sugar Transporters (SbTSTs) putatively control sucrose accumulation in sweet sorghum stems.

    PubMed

    Bihmidine, Saadia; Julius, Benjamin T; Dweikat, Ismail; Braun, David M

    2016-01-01

    Carbohydrates are differentially partitioned in sweet versus grain sorghums. While the latter preferentially accumulate starch in the grain, the former primarily store large amounts of sucrose in the stem. Previous work determined that neither sucrose metabolizing enzymes nor changes in Sucrose transporter (SUT) gene expression accounted for the carbohydrate partitioning differences. Recently, 2 additional classes of sucrose transport proteins, Tonoplast Sugar Transporters (TSTs) and SWEETs, were identified; thus, we examined whether their expression tracked sucrose accumulation in sweet sorghum stems. We determined 2 TSTs were differentially expressed in sweet vs. grain sorghum stems, likely underlying the massive difference in sucrose accumulation. A model illustrating potential roles for different classes of sugar transport proteins in sorghum sugar partitioning is discussed.

  13. Tonoplast Sugar Transporters (SbTSTs) putatively control sucrose accumulation in sweet sorghum stems

    PubMed Central

    Bihmidine, Saadia; Julius, Benjamin T; Dweikat, Ismail; Braun, David M

    2016-01-01

    ABSTRACT Carbohydrates are differentially partitioned in sweet versus grain sorghums. While the latter preferentially accumulate starch in the grain, the former primarily store large amounts of sucrose in the stem. Previous work determined that neither sucrose metabolizing enzymes nor changes in Sucrose transporter (SUT) gene expression accounted for the carbohydrate partitioning differences. Recently, 2 additional classes of sucrose transport proteins, Tonoplast Sugar Transporters (TSTs) and SWEETs, were identified; thus, we examined whether their expression tracked sucrose accumulation in sweet sorghum stems. We determined 2 TSTs were differentially expressed in sweet vs. grain sorghum stems, likely underlying the massive difference in sucrose accumulation. A model illustrating potential roles for different classes of sugar transport proteins in sorghum sugar partitioning is discussed. PMID:26619184

  14. Contaminant Accumulation in Many New England Lead Pipe Scales

    EPA Science Inventory

    Previous work has shown that contaminants such as Al, As and Ra can accumulate in drinking water distribution system solids. The release of accumulated contaminants back into the water supply could conceivably result in elevated levels at consumers' taps. The objective of this s...

  15. Deriving the Hirshfeld partitioning using distance metrics

    SciTech Connect

    Heidar-Zadeh, Farnaz; Ayers, Paul W.; Bultinck, Patrick

    2014-09-07

    The atoms in molecules associated with the Hirshfeld partitioning minimize the generalized Hellinger-Bhattacharya distance to the reference pro-atom densities. Moreover, the reference pro-atoms can be chosen by minimizing the distance between the pro-molecule density and the true molecular density. This provides an alternative to both the heuristic “stockholder” and the mathematical information-theoretic interpretations of the Hirshfeld partitioning. These results extend to any member of the family of f-divergences.

  16. Partition dataset according to amino acid type improves the prediction of deleterious non-synonymous SNPs

    SciTech Connect

    Yang, Jing; Li, Yuan-Yuan; Li, Yi-Xue; Ye, Zhi-Qiang

    2012-03-02

    Highlights: Black-Right-Pointing-Pointer Proper dataset partition can improve the prediction of deleterious nsSNPs. Black-Right-Pointing-Pointer Partition according to original residue type at nsSNP is a good criterion. Black-Right-Pointing-Pointer Similar strategy is supposed promising in other machine learning problems. -- Abstract: Many non-synonymous SNPs (nsSNPs) are associated with diseases, and numerous machine learning methods have been applied to train classifiers for sorting disease-associated nsSNPs from neutral ones. The continuously accumulated nsSNP data allows us to further explore better prediction approaches. In this work, we partitioned the training data into 20 subsets according to either original or substituted amino acid type at the nsSNP site. Using support vector machine (SVM), training classification models on each subset resulted in an overall accuracy of 76.3% or 74.9% depending on the two different partition criteria, while training on the whole dataset obtained an accuracy of only 72.6%. Moreover, the dataset was also randomly divided into 20 subsets, but the corresponding accuracy was only 73.2%. Our results demonstrated that partitioning the whole training dataset into subsets properly, i.e., according to the residue type at the nsSNP site, will improve the performance of the trained classifiers significantly, which should be valuable in developing better tools for predicting the disease-association of nsSNPs.

  17. Certificate Revocation Using Fine Grained Certificate Space Partitioning

    NASA Astrophysics Data System (ADS)

    Goyal, Vipul

    A new certificate revocation system is presented. The basic idea is to divide the certificate space into several partitions, the number of partitions being dependent on the PKI environment. Each partition contains the status of a set of certificates. A partition may either expire or be renewed at the end of a time slot. This is done efficiently using hash chains.

  18. Making Solid Geometry Solid.

    ERIC Educational Resources Information Center

    Hartz, Viggo

    1981-01-01

    Allowing students to use a polystyrene cutter to fashion their own three-dimensional models is suggested as a means of allowing individuals to experience problems and develop ideas related to solid geometry. A list of ideas that can lead to mathematical discovery is provided. (MP)

  19. Quality Partitioned Meshing of Multi-Material Objects.

    PubMed

    Zhang, Qin; Cha, Deukhyun; Bajaj, Chandrajit

    We present a simple but effective algorithm for generating topologically and geometrically consistent quality triangular surface meshing of compactly packed multiple heterogeneous domains in [Formula: see text]. By compact packing we imply that adjacent homogeneous domains or materials share some 0, 1, and/or 2 dimensional boundary. Such packed multiple material (or multi-material) solids arise naturally from classification/partitioning/segmentation of homogeneous domains in [Formula: see text] into different sub-regions. The multi-materials may also represent separate functionally classified sections or just be multiple component copies tightly fused together as perhaps by layered manufacturing processes. The input to our algorithm is a geometric representation of the entire multi-material solid, and a volumetric classification map identifying the individual materials. As output, each individual material region is represented by a triangulated 2-manifold boundary, with adjacent material regions having shared boundaries. Our algorithm has been implemented, and applied to different multi-material solids, and the results are additionally presented with quantitative analysis of detection and cure of non-manifold interfaces as well as spurious small components. These meshes are useful for combined boundary element analysis, however these simulation results are not presented.

  20. Quality Partitioned Meshing of Multi-Material Objects

    PubMed Central

    Zhang, Qin; Cha, Deukhyun; Bajaj, Chandrajit

    2016-01-01

    We present a simple but effective algorithm for generating topologically and geometrically consistent quality triangular surface meshing of compactly packed multiple heterogeneous domains in R3. By compact packing we imply that adjacent homogeneous domains or materials share some 0, 1, and/or 2 dimensional boundary. Such packed multiple material (or multi-material) solids arise naturally from classification/partitioning/segmentation of homogeneous domains in R3 into different sub-regions. The multi-materials may also represent separate functionally classified sections or just be multiple component copies tightly fused together as perhaps by layered manufacturing processes. The input to our algorithm is a geometric representation of the entire multi-material solid, and a volumetric classification map identifying the individual materials. As output, each individual material region is represented by a triangulated 2-manifold boundary, with adjacent material regions having shared boundaries. Our algorithm has been implemented, and applied to different multi-material solids, and the results are additionally presented with quantitative analysis of detection and cure of non-manifold interfaces as well as spurious small components. These meshes are useful for combined boundary element analysis, however these simulation results are not presented. PMID:27563367

  1. Screening of pesticides for environmental partitioning tendency.

    PubMed

    Gramatica, Paola; Di Guardo, Antonio

    2002-06-01

    The partitioning tendency of chemicals, in this study pesticides in particular, into different environmental compartments depends mainly on the concurrent relevance of the physico-chemical properties of the chemical itself. To rank the pesticides according to their distribution tendencies in the different environmental compartments we propose a multivariate approach: the combination, by principal component analysis, of those physico-chemical properties like organic carbon partition coefficient (Koc), n-octanol/water partition coefficient (Kow), water solubility (Sw), vapour pressure and Henry's law constant (H) that are more relevant to the determination of environmental partitioning. The resultant macrovariables, the PC1 and PC2 scores here named leaching index (LIN) and volatality index (VIN), are proposed as preliminary environmental partitioning indexes in different media. These two indexes are modeled by theoretical molecular descriptors with satisfactory predictive power. Such an approach allows a rapid pre-determination and screening of the environmental distribution of pesticides starting only from the molecular structure of the pesticide, without any a priori knowledge of the physico-chemical properties.

  2. A biologically motivated partitioning of mortality.

    PubMed

    Carnes, B A; Olshansky, S J

    1997-01-01

    For over a century, actuaries and biologists working independently of each other have presented arguments for why total mortality needs to be partitioned into biologically meaningful subcomponents. These mortality partitions tended to overlook genetic diseases that are inherited because the partitions were motivated by a paradigm focused on aging. In this article, we combine and extend the concepts from these disciplines to develop a conceptual partitioning of total mortality into extrinsic and intrinsic causes of death. An extrinsic death is either caused or initiated by something that orginates outside the body of an individual, while an intrinsic death is either caused or initiated by processes that originate within the body. It is argued that extrinsic mortality has been a driving force in determining why we die when we do from intrinsic causes of death. This biologically motivated partitioning of mortality provides a useful perspective for researchers interested in comparative mortality analyses, the consequences of population aging, limits to human life expectancy, the progress made by the biomedical sciences against lethal diseases, and demographic models that predict the life expectancy of future populations.

  3. Octanol/air partitioning of polychlorinated biphenyls

    SciTech Connect

    Komp, P.; McLachlan, M.S.

    1997-12-01

    The partitioning of 16 polychlorinated biphenyls (PCBs) between air and 1-octanol was investigated using a fugacity meter. The measurements were conducted over an environmentally relevant temperature range (10--43 C). For a given congener the measured 1-octanol/air partition coefficient K{sub OA} was exponentially proportional to the reciprocal temperature. The enthalpy of phase change (octanol to air) {Delta}H{sub OA} ranged from 71 to 93 kJ/mol. Up to log K{sub OA} values of 9.37 (corresponding to 2,2{prime},3,4{prime},5{prime},6-hexachlorobiphenyl), the enthalpy of phase change was similar to the enthalpy of vaporization of the subcooled liquid PCB. For the less volatile congeners (log K{sub OA} > 9.37), the enthalpies of vaporization exceeded the enthalpies of phase change, the difference increasing with increasing log K{sub OA}. Solubilities of the PCBs in 1-octanol were calculated from the data, and the results were in excellent agreement with octanol solubilities calculated using the OCTASOL fragment method. A very good correlation between the measured octanol/air partition coefficients and values calculated from octanol/water and air/water partition coefficients was obtained. This yielded a method to estimate reliably the octanol/air partitioning of all PCB congeners.

  4. ADSORPTION-PARTITIONING UPTAKE OF NINE LOW-POLARITY ORGANIC CHEMICALS ON A NATURAL SORBENT. (R825406)

    EPA Science Inventory

    Sorption of comparatively nonpolar organic chemicals by natural solids not
    only can be predominated by partitioning with organic matter but also can
    reflect a substantial contribution from adsorption at low relative
    concentration. Sorption of nine polycyclic aromat...

  5. The EPRL intertwiners and corrected partition function

    NASA Astrophysics Data System (ADS)

    Kamiński, Wojciech; Kisielowski, Marcin; Lewandowski, Jerzy

    2010-08-01

    Do the SU(2) intertwiners parametrize the space of the Engle, Pereira, Rovelli, Livine (EPRL) solutions to the simplicity constraint? What is the complete form of the partition function written in terms of this parametrization? We prove that the EPRL map is injective in the general n-valent vertex case for the Barbero-Immirzi parameter less than 1. We find, however, that the EPRL map is not isometric. In the consequence, a partition function can be defined either using the EPRL intertwiners Hilbert product or the SU(2) intertwiners Hilbert product. We use the EPRL one and derive a new, complete formula for the partition function. Next, we view it in terms of the SU(2) intertwiners. The result, however, goes beyond the SU(2) spin-foam models' framework and the original EPRL proposal.

  6. New parallel SOR method by domain partitioning

    SciTech Connect

    Xie, D.; Adams, L.

    1999-07-01

    In this paper the authors propose and analyze a new parallel SOR method, the PSOR method, formulated by using domain partitioning and interprocessor data communication techniques. They prove that the PSOR method has the same asymptotic rate of convergence as the Red/Black (R/B) SOR method for the five-point stencil on both strip and block partitions, and as the four-color (R/B/G/O) SOR method for the nine-point stencil on strip partitions. They also demonstrate the parallel performance of the PSOR method on four different MIMD multiprocessors (a KSR1, an Intel Delta, a Paragon, and an IBM SP2). Finally, they compare the parallel performance of PSOR, R/B SOR, and R/B/G/O SOR. Numerical results on the Paragon indicate that PSOR is more efficient than R/B SOR and R/B/G/O SOR in both computation and interprocessor data communication.

  7. Factorization of the bosonic partition function

    NASA Astrophysics Data System (ADS)

    Alsharafat, Ayed; Chair, Noureddine

    2017-04-01

    The factorization formula in the non-interacting quantum field theories that relates the fermionic partition function to the bosonic partition function considered recently by Chair (2013) [3] is obtained for the harmonic oscillator using the path integral formulation. By using the latter, the fermionic partition function turns out to be the ratio of two determinants of the same operator (∂τ + ω), whose eigenmodes being both periodic on the imaginary time intervals [ 0 , 2 β ], [ 0 , β ]. The natural generalization of the factorization formula when β →2m β is derived, such a factorization implies that the bosonic oscillator at temperature β can be seen as a non-interacting mixture of a bosonic oscillator at temperature 2m β and m-fermionic oscillators at different temperatures 2 m - k β, k = 1 , 2 , … , m. As a consequence, a general relationship between the bosonic and fermionic thermal zeta functions is deduced.

  8. Parallel algorithms for dynamically partitioning unstructured grids

    SciTech Connect

    Diniz, P.; Plimpton, S.; Hendrickson, B.; Leland, R.

    1994-10-01

    Grid partitioning is the method of choice for decomposing a wide variety of computational problems into naturally parallel pieces. In problems where computational load on the grid or the grid itself changes as the simulation progresses, the ability to repartition dynamically and in parallel is attractive for achieving higher performance. We describe three algorithms suitable for parallel dynamic load-balancing which attempt to partition unstructured grids so that computational load is balanced and communication is minimized. The execution time of algorithms and the quality of the partitions they generate are compared to results from serial partitioners for two large grids. The integration of the algorithms into a parallel particle simulation is also briefly discussed.

  9. Ionizing radiation increases systemic nanoparticle tumor accumulation

    PubMed Central

    Giustini, A.J.; Petryk, A.A.; Hoopes, P.J.

    2012-01-01

    Nanoparticle-based therapies are currently being explored for both the imaging and treatment of primary and metastatic cancers. Effective nanoparticle cancer therapy requires significant accumulations of nanoparticles within the tumor environment. Various techniques have been used to improve tumor nanoparticle uptake and biodistribution. Most notable of these techniques are the use of tumor-specific-peptide-conjugated nanoparticles and chemical modification of the nanoparticles with immune-evading polymers. Another strategy for improving the tumor uptake of the nanoparticles is modification of the tumor microenvironment with a goal of enhancing the enhanced permeability and retention effect inherent to solid tumors. We demonstrate a two-fold increase in the tumor accumulation of systemically delivered iron oxide nanoparticles following a single, 15 Gy radiation dose in a syngeneic mouse breast tumor model. This increase in nanoparticle tumor accumulation correlates with a radiation-induced decrease in tumor interstitial pressure and a subsequent increase in vascular permeability. PMID:22633900

  10. Gold and Copper Partitioning Between Vapor and Brine at 800° C and 100 MPa.

    NASA Astrophysics Data System (ADS)

    Frank, M.; Candela, P.; Piccoli, P.; Pettke, T.; Heinrich, C.

    2002-05-01

    Recent studies of fluid inclusions from porphyry-type ore deposits indicate that, although a magmatic brine may have been responsible for the generation of these deposits, high-concentrations of Au and Cu may exist in low-salinity vapor-bearing fluid inclusions as well (Ulrich et al., 1999, Nature, 399, 676). Experimental studies of Au (Frank et al., 2001, 11th Goldschmidt Conf., #3773) and Cu (Williams et al., 1995, CMP, v. 121, 388) have indicated that those elements will partition into a high-salinity brine relative to a low-salinity vapor in a sulfur-poor environment. To this point, the conditions under which Au and Cu will partition into a vapor relative to a brine have not been reproduced experimentally. Therefore, the question we wish to address is: Under what conditions will Au and Cu partition preferentially into a vapor relative to a brine? In an attempt to answer this, we performed experiments in the brine-vapor-haplogranitic melt-intermediate solid solution-pyrrhotite-quartz system at 800° C, 100 MPa and oxygen fugacity buffered by Ni-NiO. The coexisting brine ( ~68wt.% NaCl equivalent) and vapor ( ~3wt.% NaCl equivalent) were composed of NaCl+KCl+HCl+H2O, with starting HCl set to either ~160 or ~1600 ppm in the aqueous mixture. Vapor and brine bearing fluid inclusions were trapped in quartz during the experiment. Select fluid inclusions were drilled out of polished quartz samples using an ArF Excimer laser (output energy of 220 mJ at 30 kV) and analyzed by Inductively Coupled Plasma-Mass Spectrometry (ELAN 6000). Counts of Au, Cu, Fe, and K were related to those of Na (internal standard) to calculate concentrations of those elements in the fluid inclusions. Analyses revealed that at ~160 ppm HCl in the aqueous mixture, Au and Cu partitioned preferentially into the brine with partition coefficients of ~14 and ~7, respectively. Au and Cu partition coefficients were ~2 and ~8 at ~1600 ppm HCl in the aqueous mixture. These data indicate that Au and Cu

  11. Partitioning SAT Instances for Distributed Solving

    NASA Astrophysics Data System (ADS)

    Hyvärinen, Antti E. J.; Junttila, Tommi; Niemelä, Ilkka

    In this paper we study the problem of solving hard propositional satisfiability problem (SAT) instances in a computing grid or cloud, where run times and communication between parallel running computations are limited.We study analytically an approach where the instance is partitioned iteratively into a tree of subproblems and each node in the tree is solved in parallel.We present new methods for constructing partitions which combine clause learning and lookahead. The methods are incorporated into the iterative approach and its performance is demonstrated with an extensive comparison against the best sequential solvers in the SAT competition 2009 as well as against two efficient parallel solvers.

  12. Chiral partition functions of quantum Hall droplets

    SciTech Connect

    Cappelli, Andrea Viola, Giovanni; Zemba, Guillermo R.

    2010-02-15

    Chiral partition functions of conformal field theory describe the edge excitations of isolated Hall droplets. They are characterized by an index specifying the quasiparticle sector and transform among themselves by a finite-dimensional representation of the modular group. The partition functions are derived and used to describe electron transitions leading to Coulomb blockade conductance peaks. We find the peak patterns for Abelian hierarchical states and non-Abelian Read-Rezayi states, and compare them. Experimental observation of these features can check the qualitative properties of the conformal field theory description, such as the decomposition of the Hilbert space into sectors, involving charged and neutral parts, and the fusion rules.

  13. Cochlear implant in incomplete partition type I.

    PubMed

    Berrettini, S; Forli, F; De Vito, A; Bruschini, L; Quaranta, N

    2013-02-01

    In this investigation, we report on 4 patients affected by incomplete partition type I submitted to cochlear implant at our institutions. Preoperative, surgical, mapping and follow-up issues as well as results in cases with this complex malformation are described. The cases reported in the present study confirm that cochlear implantation in patients with incomplete partition type I may be challenging for cochlear implant teams. The results are variable, but in many cases satisfactory, and are mainly related to the surgical placement of the electrode and residual neural nerve fibres. Moreover, in some cases the association of cochlear nerve abnormalities and other disabilities may significantly affect results.

  14. Evidence for melt partitioning between olivine and orthopyroxene in partially molten harzburgite

    NASA Astrophysics Data System (ADS)

    Miller, K.; Zhu, W.; Montesi, L. G.; Le Roux, V.; Gaetani, G. A.

    2013-12-01

    During melting at mid-ocean ridges, melt is driven into an equilibrium, minimum-energy configuration by surface energy gradients between solid-solid and solid-liquid phase boundaries. Such a configuration, where melt is mostly restricted to three and four-grain junctions, acts as a porous medium through which melt can percolate to the surface. For a monomineralic system, melt is distributed evenly among all grains. However, in mineralogical heterogeneous systems, melt partitions unevenly between the various solid phases to minimize the total energy of the system. In a ocean ridge melting environment, where olivine is often juxtaposed against orthopyroxene (opx), lithologic partitioning is expected to turn olivine-rich regions into high-permeability conduits, through which melt can be quickly extracted, drastically increasing the permeability of the mantle [Zhu and Hirth, 2003]. Lithologic partitioning has been demonstrated in experiments using analogue systems [Watson, 1999]; however, to date, no experiment has confirmed its existence in partially molten mantle systems. We present experimental results that determine the degree of melt partitioning between olivine and opx in partially molten harzburgites. Samples were prepared from a powdered mixture of oxides and carbonates and then hot-pressed in a solid-media piston-cylinder apparatus at 1350°C and 1.5GPa [Zhu et al., 2011] to achieve an 82/18 vol. % ratio of olivine to opx. Prior to hot-pressing, basalt was added to the powdered mixtures in various proportions to test for lithologic partitioning across a range of melt fractions. Three-dimensional, 700nm-resolution images of our samples were obtained using synchrotron X-ray microtomography on the 2BM station of the Advanced Photon Source at Argonne National Labs. Image data were filtered using an anisotropic diffusion filter to enhance phase contrast and then segmented to produce binary representations of each phase. In order to quantitatively demonstrate

  15. Visualising the equilibrium distribution and mobility of organic contaminants in soil using the chemical partitioning space.

    PubMed

    Wong, Fiona; Wania, Frank

    2011-06-01

    Assessing the behaviour of organic chemicals in soil is a complex task as it is governed by the physical chemical properties of the chemicals, the characteristics of the soil as well as the ambient conditions of the environment. The chemical partitioning space, defined by the air-water partition coefficient (K(AW)) and the soil organic carbon-water partition coefficient (K(OC)), was employed to visualize the equilibrium distribution of organic contaminants between the air-filled pores, the pore water and the solid phases of the bulk soil and the relative importance of the three transport processes removing contaminants from soil (evaporation, leaching and particle erosion). The partitioning properties of twenty neutral organic chemicals (i.e. herbicides, pharmaceuticals, polychlorinated biphenyls and volatile chemicals) were estimated using poly-parameter linear free energy relationships and superimposed onto these maps. This allows instantaneous estimation of the equilibrium phase distribution and mobility of neutral organic chemicals in soil. Although there is a link between the major phase and the dominant transport process, such that chemicals found in air-filled pore space are subject to evaporation, those in water-filled pore space undergo leaching and those in the sorbed phase are associated with particle erosion, the partitioning coefficient thresholds for distribution and mobility can often deviate by many orders of magnitude. In particular, even a small fraction of chemical in pore water or pore air allows for evaporation and leaching to dominate over solid phase transport. Multiple maps that represent soils that differ in the amount and type of soil organic matter, water saturation, temperature, depth of surface soil horizon, and mineral matters were evaluated.

  16. EVALUATION OF SOLID ADSORBENTS FOR THE COLLECTION AND ANALYSES OF AMBIENT BIOGENIC VOLATILE ORGANICS

    EPA Science Inventory

    Micrometeorological flux measurements of biogenic volatile organic compounds (BVOCs) usually require that large volumes of air be collected (whole air samples) or focused during the sampling process (cryogenic trapping or gas-solid partitioning on adsorbents) in order to achiev...

  17. Equivalence of partition properties and determinacy

    PubMed Central

    Kechris, Alexander S.; Woodin, W. Hugh

    1983-01-01

    It is shown that, within L(ℝ), the smallest inner model of set theory containing the reals, the axiom of determinacy is equivalent to the existence of arbitrarily large cardinals below Θ with the strong partition property κ → (κ)κ. PMID:16593299

  18. Mapping Pesticide Partition Coefficients By Electromagnetic Induction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A potential method for reducing pesticide leaching is to base application rates on the leaching potential of a specific chemical and soil combination. However, leaching is determined in part by the partitioning of the chemical between the soil and soil solution, which varies across a field. Standard...

  19. A review of approaches for evapotranspiration partitioning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Partitioning of evapotranspiration (ET) into evaporation from the soil surface (E) and transpiration (T) is challenging but important in order to assess biomass production and the allocation of increasingly scarce water resources. Generally T is the desired component with the water being used to enh...

  20. A Partition Formula for Fibonacci Numbers

    NASA Astrophysics Data System (ADS)

    Fahr, Philipp; Ringerl, Claus Michael

    2008-02-01

    We present a partition formula for the even index Fibonacci numbers. The formula is motivated by the appearance of these Fibonacci numbers in the representation theory of the socalled 3-Kronecker quiver, i.e., the oriented graph with two vertices and three arrows in the same direction.

  1. 25 CFR 152.33 - Partition.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER ISSUANCE OF PATENTS IN FEE, CERTIFICATES OF COMPETENCY, REMOVAL OF RESTRICTIONS, AND SALE OF CERTAIN INDIAN LANDS Partitions in Kind of Inherited Allotments § 152..., regardless of their competency, patents in fee to be issued to the competent heirs for their shares and...

  2. 25 CFR 152.33 - Partition.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER ISSUANCE OF PATENTS IN FEE, CERTIFICATES OF COMPETENCY, REMOVAL OF RESTRICTIONS, AND SALE OF CERTAIN INDIAN LANDS Partitions in Kind of Inherited Allotments § 152..., regardless of their competency, patents in fee to be issued to the competent heirs for their shares and...

  3. 25 CFR 152.33 - Partition.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER ISSUANCE OF PATENTS IN FEE, CERTIFICATES OF COMPETENCY, REMOVAL OF RESTRICTIONS, AND SALE OF CERTAIN INDIAN LANDS Partitions in Kind of Inherited Allotments § 152..., regardless of their competency, patents in fee to be issued to the competent heirs for their shares and...

  4. 25 CFR 152.33 - Partition.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER ISSUANCE OF PATENTS IN FEE, CERTIFICATES OF COMPETENCY, REMOVAL OF RESTRICTIONS, AND SALE OF CERTAIN INDIAN LANDS Partitions in Kind of Inherited Allotments § 152..., regardless of their competency, patents in fee to be issued to the competent heirs for their shares and...

  5. 25 CFR 152.33 - Partition.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER ISSUANCE OF PATENTS IN FEE, CERTIFICATES OF COMPETENCY, REMOVAL OF RESTRICTIONS, AND SALE OF CERTAIN INDIAN LANDS Partitions in Kind of Inherited Allotments § 152..., regardless of their competency, patents in fee to be issued to the competent heirs for their shares and...

  6. Set Partitions and the Multiplication Principle

    ERIC Educational Resources Information Center

    Lockwood, Elise; Caughman, John S., IV

    2016-01-01

    To further understand student thinking in the context of combinatorial enumeration, we examine student work on a problem involving set partitions. In this context, we note some key features of the multiplication principle that were often not attended to by students. We also share a productive way of thinking that emerged for several students who…

  7. Zr partitioning and kinetics and mechanism

    NASA Technical Reports Server (NTRS)

    Taylor, L. A.

    1973-01-01

    The results of investigations concerning the cooling histories of lunar rocks are reported. Publications resulting from this research are listed. Studies discussed include the partitioning of Zr between FeTi03 and Fe2Ti04 in the presence of Fe + Zr02, and ulvospinel reduction.

  8. Application of partition technology to particle electrophoresis

    NASA Technical Reports Server (NTRS)

    Van Alstine, James M.; Harris, J. Milton; Karr, Laurel J.; Bamberger, Stephan; Matsos, Helen C.; Snyder, Robert S.

    1989-01-01

    The effects of polymer-ligand concentration on particle electrophoretic mobility and partition in aqueous polymer two-phase systems are investigated. Polymer coating chemistry and affinity ligand synthesis, purification, and analysis are conducted. It is observed that poly (ethylene glycol)-ligands are effective for controlling particle electrophoretic mobility.

  9. Nitrogen Accumulation and Partitioning in High Arctic Tundra from Extreme Atmospheric N Deposition Events

    NASA Astrophysics Data System (ADS)

    Phoenix, G. K.; Osborn, A.; Blaud, A.; Press, M. C.; Choudhary, S.

    2013-12-01

    Arctic ecosystems are threatened by pollution from extreme atmospheric nitrogen (N) deposition events. These events occur from the long-range transport of reactive N from pollution sources at lower latitudes and can deposit up to 80% of the annual N deposition in just a few days. To date, the fate and impacts of these extreme pollutant events has remained unknown. Using a field simulation study, we undertook the first assessment of the fate of acutely deposited N on arctic tundra. Extreme N deposition events were simulated on field plots at Ny-Ålesund, Svalbard (79oN) at rates of 0, 0.04, 0.4 and 1.2 g N m-2 yr-1 applied as NH4NO3 solution over 4 days, with 15N tracers used in the second year to quantify the fate of the deposited N in the plant, soil, microbial and leachate pools. Separate applications of 15NO3- and 15NH4+ were also made to determine the importance of N form in the fate of N. Recovery of the 15N tracer at the end of the first growing season approached 100% of the 15N applied irrespective of treatment level, demonstrating the considerable capacity of High Arctic tundra to capture pollutant N from extreme deposition events. Most incorporation of the 15N was found in bryophytes, followed by the dominant vascular plant (Salix polaris) and the microbial biomass of the soil organic layer. Total recovery remained high in the second growing season (average of 90%), indicating highly conservative N retention. Between the two N forms, recovery of 15NO3- and 15NH4+ were equal in the non-vascular plants, whereas in the vascular plants (particularly Salix polaris) recovery of 15NO3- was four times higher than of 15NH4+. Overall, these findings show that High Arctic tundra has considerable capacity to capture and retain the pollutant N deposited in acute extreme deposition events. Given they can represent much of the annual N deposition, extreme deposition events may be more important than increased chronic N deposition as a pollution source. Furthermore, current extreme N deposition events -and the predicted future increase in extreme deposition events- may represent an important source of eutrophication to 'pristine' arctic tundra.

  10. Chimpanzee accumulative stone throwing.

    PubMed

    Kühl, Hjalmar S; Kalan, Ammie K; Arandjelovic, Mimi; Aubert, Floris; D'Auvergne, Lucy; Goedmakers, Annemarie; Jones, Sorrel; Kehoe, Laura; Regnaut, Sebastien; Tickle, Alexander; Ton, Els; van Schijndel, Joost; Abwe, Ekwoge E; Angedakin, Samuel; Agbor, Anthony; Ayimisin, Emmanuel Ayuk; Bailey, Emma; Bessone, Mattia; Bonnet, Matthieu; Brazolla, Gregory; Buh, Valentine Ebua; Chancellor, Rebecca; Cipoletta, Chloe; Cohen, Heather; Corogenes, Katherine; Coupland, Charlotte; Curran, Bryan; Deschner, Tobias; Dierks, Karsten; Dieguez, Paula; Dilambaka, Emmanuel; Diotoh, Orume; Dowd, Dervla; Dunn, Andrew; Eshuis, Henk; Fernandez, Rumen; Ginath, Yisa; Hart, John; Hedwig, Daniela; Ter Heegde, Martijn; Hicks, Thurston Cleveland; Imong, Inaoyom; Jeffery, Kathryn J; Junker, Jessica; Kadam, Parag; Kambi, Mohamed; Kienast, Ivonne; Kujirakwinja, Deo; Langergraber, Kevin; Lapeyre, Vincent; Lapuente, Juan; Lee, Kevin; Leinert, Vera; Meier, Amelia; Maretti, Giovanna; Marrocoli, Sergio; Mbi, Tanyi Julius; Mihindou, Vianet; Moebius, Yasmin; Morgan, David; Morgan, Bethan; Mulindahabi, Felix; Murai, Mizuki; Niyigabae, Protais; Normand, Emma; Ntare, Nicolas; Ormsby, Lucy Jayne; Piel, Alex; Pruetz, Jill; Rundus, Aaron; Sanz, Crickette; Sommer, Volker; Stewart, Fiona; Tagg, Nikki; Vanleeuwe, Hilde; Vergnes, Virginie; Willie, Jacob; Wittig, Roman M; Zuberbuehler, Klaus; Boesch, Christophe

    2016-02-29

    The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites.

  11. Accumulation of the planets

    NASA Technical Reports Server (NTRS)

    Wetherill, G. W.

    1987-01-01

    In modeling the accumulation of planetesimals into planets, it is appropriate to distinguish between two stages: an early stage, during which approximately 10 km diameter planetesimals accumulate locally to form bodies approximate 10 to the 25th g in mass; and a later stage in which the approximately 10 to the 25th g planetesimals accumulate into the final planets. In the terrestrial planet region, an initial planetesimal swarm corresponding to the critical mass of dust layer gravitational instabilities is considered. In order to better understand the accumulation history of Mercury-sized bodies, 19 Monte-Carlo simulations of terrestrial planet growth were calculated. A Monte Carlo technique was used to investigate the orbital evolution of asteroidal collision debris produced interior to 2.6 AU. It was found that there are two regions primarily responsible for production of Earth-crossing meteoritic material and Apollo objects. The same techniques were extended to include the origin of Earth-approaching asteroidal bodies. It is found that these same two resonant mechanisms predict a steady-state number of Apollo-Amor about 1/2 that estimated based on astronomical observations.

  12. Chimpanzee accumulative stone throwing

    PubMed Central

    Kühl, Hjalmar S.; Kalan, Ammie K.; Arandjelovic, Mimi; Aubert, Floris; D’Auvergne, Lucy; Goedmakers, Annemarie; Jones, Sorrel; Kehoe, Laura; Regnaut, Sebastien; Tickle, Alexander; Ton, Els; van Schijndel, Joost; Abwe, Ekwoge E.; Angedakin, Samuel; Agbor, Anthony; Ayimisin, Emmanuel Ayuk; Bailey, Emma; Bessone, Mattia; Bonnet, Matthieu; Brazolla, Gregory; Buh, Valentine Ebua; Chancellor, Rebecca; Cipoletta, Chloe; Cohen, Heather; Corogenes, Katherine; Coupland, Charlotte; Curran, Bryan; Deschner, Tobias; Dierks, Karsten; Dieguez, Paula; Dilambaka, Emmanuel; Diotoh, Orume; Dowd, Dervla; Dunn, Andrew; Eshuis, Henk; Fernandez, Rumen; Ginath, Yisa; Hart, John; Hedwig, Daniela; Ter Heegde, Martijn; Hicks, Thurston Cleveland; Imong, Inaoyom; Jeffery, Kathryn J.; Junker, Jessica; Kadam, Parag; Kambi, Mohamed; Kienast, Ivonne; Kujirakwinja, Deo; Langergraber, Kevin; Lapeyre, Vincent; Lapuente, Juan; Lee, Kevin; Leinert, Vera; Meier, Amelia; Maretti, Giovanna; Marrocoli, Sergio; Mbi, Tanyi Julius; Mihindou, Vianet; Moebius, Yasmin; Morgan, David; Morgan, Bethan; Mulindahabi, Felix; Murai, Mizuki; Niyigabae, Protais; Normand, Emma; Ntare, Nicolas; Ormsby, Lucy Jayne; Piel, Alex; Pruetz, Jill; Rundus, Aaron; Sanz, Crickette; Sommer, Volker; Stewart, Fiona; Tagg, Nikki; Vanleeuwe, Hilde; Vergnes, Virginie; Willie, Jacob; Wittig, Roman M.; Zuberbuehler, Klaus; Boesch, Christophe

    2016-01-01

    The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites. PMID:26923684

  13. Isotope fractionation of benzene during partitioning - Revisited.

    PubMed

    Kopinke, F-D; Georgi, A; Imfeld, G; Richnow, H-H

    2017-02-01

    Isotope fractionation between benzene-D0 and benzene-D6 caused by multi-step partitioning of the benzenes between water and two organic solvents, n-octane and 1-octanol, as well as between water and the gas phase, was measured. The obtained fractionation factors αH = KH/KD are αH = 1.080 ± 0.015 and αH = 1.074 ± 0.015 for extraction into n-octane and 1-octanol, respectively, and αH = 1.049 ± 0.010 for evaporation from aqueous solution. The comparison of solvent- and gas-phase partitioning reveals that about 2/3 of the driving force of fractionation is due to different interactions in the aqueous phase, whereas 1/3 is due to different interactions in the organic phase. The heavy benzene isotopologue behaves more 'hydrophilically' and the light one more 'hydrophobically'. This synergistic alignment gives rise to relatively large fractionation effects in partitioning between water and non-polar organic matter. In contrast to a previous study, there is no indication of strong fractionation by specific interactions between benzene and octanol. Partitioning under non-equilibrium conditions yields smaller apparent fractionation effects due to opposite trends of thermodynamic and kinetic fractionation parameters, i.e. partition and diffusion coefficients of the isotopologues. This may have consequences which should be taken into account when considering isotope fractionation due to sorption in environmental compartments.

  14. Spontaneous Formation of Water Droplets at Oil-Solid Interfaces

    PubMed Central

    Yang, Zhongqiang; Abbott, Nicholas L.

    2010-01-01

    We report observations of spontaneous formation of micrometer-sized water droplets within micrometer-thick films of a range of different oils (isotropic and nematic 4-cyano-4’-pentylbiphenyl (5CB), and silicone, olive and corn oil) that are supported on glass substrates treated with octadecyltrichlorosilane (OTS) and immersed under water. Confocal imaging was used to determine that the water droplets nucleate and grow at the interface between the oils and OTS-treated glass with a contact angle of ~130°. A simple thermodynamic model based on macroscopic interfacial energetic arguments consistent with the contact angle of 130°, however, fails to account for the spontaneous formation of the water droplets. ζ-potential measurements performed with OTS-treated glass (− 59.0 ± 16.4 mV) and hydrophobic monolayers formed on gold films (2.0 ± 0.7 mV), when combined with the observed absence of droplet formation under films of oil supported on the latter surfaces, suggest that the charge of the oil-solid interface promotes partitioning of water to the interfacial region. The hydrophobic nature of the OTS-treated glass promotes dewetting of water accumulated in the interfacial region into droplets (a thin film of water is seen to form on bare glass). The inhibitory effect on droplet formation of both salt (NaCl) and sucrose (0.1mM to 500mM) added to the aqueous phase was similar, indicating that both solutes lower the chemical potential of the bulk water (osmotic effect) sufficiently to prevent partitioning of the water to the interface between the oil and supporting substrates. These results suggest that charged, hydrophobic surfaces can provide routes to spontaneous formation of surface-supported, water-in-oil emulsions. PMID:20712383

  15. Partitioning of Inorganic Elements Consumed by Humans Between the Various Fractions of Human Wastes: A Review and Analysis of Existing Literature

    NASA Technical Reports Server (NTRS)

    Wignarajah, K.; Fisher, John W.; Pisharody, Suresh A.

    2003-01-01

    The nutritional requirements of humans and astronauts are well defined and show consistency, but the same cannot be said of human wastes. Nutrients taken up by humans can be considered to fall into two major categories - organic and inorganic fractions. Carbon, hydrogen, oxygen, nitrogen and sulfur are elements that are associated with the organic fraction. These elements are taken up in large amounts by humans and when metabolized released in wastes often in gaseous forms or as water. On the other hand, a large number of the elements are simply exchanged and can be accounted for in the liquid and solid wastes of humans. These elements fall into three major categories - cationic macroelements (e.g. Ca, K, Na, Mg and Si), anionic macroelements (e.g P, S and Cl), 17 essential microelements, (e.g. Fe, Mn, Cr, Co, Cu, Zn, Se and Sr). When provided in the recommended concentrations to an adult human, these elements should not normally accumulate in humans, but will be excreted in the different human wastes. Knowledge of the partitioning of these elements between the different human waste fractions is fundamental to understanding (a) how these elements can be recovered for reuse in space habitats, and (b) to developing the processors for waste management. The current literature is exhaustive but sometimes also conflicting. We have used the existing knowledge of nutrition and waste from medical literature and NASA documentation to develop a consensus to typify and chemically characterize the various human wastes. The partitioning of these elements has been developed into a functional model.

  16. Open software tools for eddy covariance flux partitioning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agro-ecosystem management and assessment will benefit greatly from the development of reliable techniques for partitioning evapotranspiration (ET) into evaporation (E) and transpiration (T). Among other activities, flux partitioning can aid in evaluating consumptive vs. non-consumptive agricultural...

  17. Altered nucleic acid partitioning during phenol extraction or silica adsorption by guanidinium and potassium salts.

    PubMed

    Xu, Lei; Lv, Jun; Ling, Liefeng; Wang, Peng; Song, Ping; Su, Ruirui; Zhu, Guoping

    2011-12-15

    Nucleic acids were found to partition into the phenol phase during phenol extraction in the presence of guanidinium at certain concentrations under acidic conditions. The guanidinium-concentration-dependent nucleic acid partitioning patterns were analogous to those of the nucleic acid adsorption/partitioning onto silica mediated by guanidinium, which implied that phenol and silica interact with nucleic acids through similar mechanisms. A competition effect was observed in which the nucleic acids that had partitioned into the phenol phase or onto the silica solid phase could be recovered to the aqueous phases by potassium in a molecular weight-salt concentration-dependent manner (the higher molecular weight nucleic acids needed higher concentrations of potassium to be recovered, and vice versa). Methods were developed based on these findings to isolate total RNA from Escherichia coli. By controlling the concentrations of guanidinium and potassium salts used before phenol extraction or silica adsorption, we can selectively recover total RNA but not the high molecular weight genomic DNA in the aqueous phases. Genomic DNA-free total RNA obtained by our methods is suitable for RT-PCR or other purposes. The methods can also be adapted to isolate small RNAs or RNA in certain molecular weight ranges by changing the salt concentrations used.

  18. Using Reward/Utility Based Impact Scores in Partitioning

    DTIC Science & Technology

    2014-05-01

    ing approach called Reward/Utility-Based Impact ( RUBI ). RUBI nds an e ective partitioning of agents while requir- ing no prior domain knowledge...provides better performance by discovering a non-trivial agent partitioning, and leads to faster simulations. We test RUBI in the Air Tra c Flow Management...partitioning with RUBI in the ATFMP, there is a 37% increase in per- formance, with a 510x speed up per simulation step over non-partitioning approaches

  19. 47 CFR 27.904 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Geographic partitioning and spectrum... partitioning and spectrum disaggregation. An entity that acquires a portion of a 1670-1675 MHz band licensee's geographic area or spectrum subject to a geographic partitioning or spectrum disaggregation agreement...

  20. 47 CFR 27.805 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Geographic partitioning and spectrum... partitioning and spectrum disaggregation. An entity that acquires a portion of a 1.4 GHz band licensee's geographic area or spectrum subject to a geographic partitioning or spectrum disaggregation agreement...

  1. 47 CFR 90.911 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Partitioned licenses and disaggregated spectrum... Specialized Mobile Radio Service § 90.911 Partitioned licenses and disaggregated spectrum. (a) Eligibility...) that constitute the partitioned area. (2) Disaggregation. Spectrum may be disaggregated in any...

  2. 47 CFR 27.805 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Geographic partitioning and spectrum... partitioning and spectrum disaggregation. An entity that acquires a portion of a 1.4 GHz band licensee's geographic area or spectrum subject to a geographic partitioning or spectrum disaggregation agreement...

  3. 47 CFR 90.911 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Partitioned licenses and disaggregated spectrum... Specialized Mobile Radio Service § 90.911 Partitioned licenses and disaggregated spectrum. (a) Eligibility...) that constitute the partitioned area. (2) Disaggregation. Spectrum may be disaggregated in any...

  4. 47 CFR 90.911 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Partitioned licenses and disaggregated spectrum... Specialized Mobile Radio Service § 90.911 Partitioned licenses and disaggregated spectrum. (a) Eligibility...) that constitute the partitioned area. (2) Disaggregation. Spectrum may be disaggregated in any...

  5. 47 CFR 95.823 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. Parties seeking Commission approval of geographic partitioning or spectrum disaggregation of 218-219 MHz Service system licenses shall request...

  6. 47 CFR 27.904 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Geographic partitioning and spectrum... partitioning and spectrum disaggregation. An entity that acquires a portion of a 1670-1675 MHz band licensee's geographic area or spectrum subject to a geographic partitioning or spectrum disaggregation agreement...

  7. 47 CFR 27.904 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Geographic partitioning and spectrum... partitioning and spectrum disaggregation. An entity that acquires a portion of a 1670-1675 MHz band licensee's geographic area or spectrum subject to a geographic partitioning or spectrum disaggregation agreement...

  8. 47 CFR 27.805 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Geographic partitioning and spectrum... partitioning and spectrum disaggregation. An entity that acquires a portion of a 1.4 GHz band licensee's geographic area or spectrum subject to a geographic partitioning or spectrum disaggregation agreement...

  9. 47 CFR 27.904 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Geographic partitioning and spectrum... partitioning and spectrum disaggregation. An entity that acquires a portion of a 1670-1675 MHz band licensee's geographic area or spectrum subject to a geographic partitioning or spectrum disaggregation agreement...

  10. 47 CFR 95.823 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. Parties seeking Commission approval of geographic partitioning or spectrum disaggregation of 218-219 MHz Service system licenses shall request...

  11. 47 CFR 90.813 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Partitioned licenses and disaggregated spectrum... Specialized Mobile Radio Service § 90.813 Partitioned licenses and disaggregated spectrum. (a) Eligibility.... Spectrum may be disaggregated in any amount. (3) Combined partitioning and disaggregation. The...

  12. 47 CFR 90.813 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Partitioned licenses and disaggregated spectrum... Specialized Mobile Radio Service § 90.813 Partitioned licenses and disaggregated spectrum. (a) Eligibility.... Spectrum may be disaggregated in any amount. (3) Combined partitioning and disaggregation. The...

  13. 47 CFR 90.911 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Partitioned licenses and disaggregated spectrum... Specialized Mobile Radio Service § 90.911 Partitioned licenses and disaggregated spectrum. (a) Eligibility...) that constitute the partitioned area. (2) Disaggregation. Spectrum may be disaggregated in any...

  14. 47 CFR 90.813 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Partitioned licenses and disaggregated spectrum... Specialized Mobile Radio Service § 90.813 Partitioned licenses and disaggregated spectrum. (a) Eligibility.... Spectrum may be disaggregated in any amount. (3) Combined partitioning and disaggregation. The...

  15. 47 CFR 27.904 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Geographic partitioning and spectrum... partitioning and spectrum disaggregation. An entity that acquires a portion of a 1670-1675 MHz band licensee's geographic area or spectrum subject to a geographic partitioning or spectrum disaggregation agreement...

  16. 47 CFR 95.823 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. Parties seeking Commission approval of geographic partitioning or spectrum disaggregation of 218-219 MHz Service system licenses shall request...

  17. 47 CFR 90.813 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Partitioned licenses and disaggregated spectrum... Specialized Mobile Radio Service § 90.813 Partitioned licenses and disaggregated spectrum. (a) Eligibility.... Spectrum may be disaggregated in any amount. (3) Combined partitioning and disaggregation. The...

  18. 47 CFR 90.911 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Partitioned licenses and disaggregated spectrum... Specialized Mobile Radio Service § 90.911 Partitioned licenses and disaggregated spectrum. (a) Eligibility...) that constitute the partitioned area. (2) Disaggregation. Spectrum may be disaggregated in any...

  19. 47 CFR 95.823 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. Parties seeking Commission approval of geographic partitioning or spectrum disaggregation of 218-219 MHz Service system licenses shall request...

  20. 47 CFR 27.805 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Geographic partitioning and spectrum... partitioning and spectrum disaggregation. An entity that acquires a portion of a 1.4 GHz band licensee's geographic area or spectrum subject to a geographic partitioning or spectrum disaggregation agreement...

  1. 47 CFR 95.823 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. Parties seeking Commission approval of geographic partitioning or spectrum disaggregation of 218-219 MHz Service system licenses shall request...

  2. 47 CFR 90.813 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Partitioned licenses and disaggregated spectrum... Specialized Mobile Radio Service § 90.813 Partitioned licenses and disaggregated spectrum. (a) Eligibility.... Spectrum may be disaggregated in any amount. (3) Combined partitioning and disaggregation. The...

  3. 47 CFR 27.805 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Geographic partitioning and spectrum... partitioning and spectrum disaggregation. An entity that acquires a portion of a 1.4 GHz band licensee's geographic area or spectrum subject to a geographic partitioning or spectrum disaggregation agreement...

  4. 33. Elevation of Doors / Typical Cement Toilet Partitions / ...

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

    33. Elevation of Doors / Typical Cement Toilet Partitions / Typical Cement Shower Bath Partitions / Typical Marble Shower Bath Partitions / Dispensary Cupboard Supply Room Cupboard Similar / Section / Kitchen Cupboard and Sink / Screened Porch Cupboard (drawing 10) - Whittier State School, Hospital & Receiving Building, 11850 East Whittier Boulevard, Whittier, Los Angeles County, CA

  5. Rare earth element partitioning between hydrous ferric oxides and acid mine water during iron oxidation

    USGS Publications Warehouse

    Verplanck, P.L.; Nordstrom, D.K.; Taylor, H.E.; Kimball, B.A.

    2004-01-01

    Ferrous iron rapidly oxidizes to Fe (III) and precipitates as hydrous Fe (III) oxides in acid mine waters. This study examines the effect of Fe precipitation on the rare earth element (REE) geochemistry of acid mine waters to determine the pH range over which REEs behave conservatively and the range over which attenuation and fractionation occur. Two field studies were designed to investigate REE attenuation during Fe oxidation in acidic, alpine surface waters. To complement these field studies, a suite of six acid mine waters with a pH range from 1.6 to 6.1 were collected and allowed to oxidize in the laboratory at ambient conditions to determine the partitioning of REEs during Fe oxidation and precipitation. Results from field experiments document that even with substantial Fe oxidation, the REEs remain dissolved in acid, sulfate waters with pH below 5.1. Between pH 5.1 and 6.6 the REEs partitioned to the solid phases in the water column, and heavy REEs were preferentially removed compared to light REEs. Laboratory experiments corroborated field data with the most solid-phase partitioning occurring in the waters with the highest pH. ?? 2004 Elsevier Ltd. All rights reserved.

  6. Octanol-water partition coefficient of benzo(a)pyrene: measurement, calculation, and environmental implications

    SciTech Connect

    Mallon, B.J.; Harrison, F.L.

    1984-03-01

    Benzo(a)pyrene (BaP) is a potent carcinogen produced in significant quantities during pyrolysis of such substances as coal, wood, and cigarettes. Several researchers have shown that the lipophilic storage and soil sediment accumulation of many organic solutes is proportional to the partitioning between octanol-1 and water. The octanol-water partition coefficient (P) is defined as P = C/sub o//C/sub w/, where C/sub o/ and C/sub w/ are the concentration of the solute in n-octanol and water. Considerable data are available demonstrating that P values measured in the laboratory can be used to predict the environmental behavior of organic pollutants. Literature searches reveal that calculated, but not measured, log P values are reported for BaP. This laboratory study was initiated to define better the log P of BaP.

  7. Fructokinase is required for carbon partitioning to cellulose in aspen wood.

    PubMed

    Roach, Melissa; Gerber, Lorenz; Sandquist, David; Gorzsás, András; Hedenström, Mattias; Kumar, Manoj; Steinhauser, Marie Caroline; Feil, Regina; Daniel, Geoffrey; Stitt, Mark; Sundberg, Björn; Niittylä, Totte

    2012-06-01

    Sucrose is the main transported form of carbon in several plant species, including Populus species. Sucrose metabolism in developing wood has therefore a central role in carbon partitioning to stem biomass. Half of the sucrose-derived carbon is in the form of fructose, but metabolism of fructose has received little attention as a factor in carbon partitioning to walls of wood cells. We show that RNAi-mediated reduction of FRK2 activity in developing wood of hybrid aspen (Populus tremula × tremuloides) led to the accumulation of soluble neutral sugars and a decrease in hexose phosphates and UDP-glucose, indicating that carbon flux to cell-wall polysaccharide precursors is decreased. Reduced FRK2 activity also led to thinner fiber cell walls with a reduction in the proportion of cellulose. No pleiotropic effects on stem height or diameter were observed. The results establish a central role for FRK2 activity in carbon flux to wood cellulose.

  8. Control of helium accumulation

    SciTech Connect

    Varadarajan, V.; Miley, G.H.

    1990-01-01

    The fishbone like oscillations in ignited tokamaks are addressed in an exploratory manner. The effects of the strong m = 1 oscillations and the weak high-frequency oscillations are examined in order to explore the feasibility of utilizing these oscillations for alpha accumulation control. The prospects of achieving small scale continuous alpha removal from the plasma center by mild fishbone-like oscillations are examined.

  9. The Benefits of Adaptive Partitioning for Parallel AMR Applications

    SciTech Connect

    Steensland, Johan

    2008-07-01

    Parallel adaptive mesh refinement methods potentially lead to realistic modeling of complex three-dimensional physical phenomena. However, the dynamics inherent in these methods present significant challenges in data partitioning and load balancing. Significant human resources, including time, effort, experience, and knowledge, are required for determining the optimal partitioning technique for each new simulation. In reality, scientists resort to using the on-board partitioner of the computational framework, or to using the partitioning industry standard, ParMetis. Adaptive partitioning refers to repeatedly selecting, configuring and invoking the optimal partitioning technique at run-time, based on the current state of the computer and application. In theory, adaptive partitioning automatically delivers superior performance and eliminates the need for repeatedly spending valuable human resources for determining the optimal static partitioning technique. In practice, however, enabling frameworks are non-existent due to the inherent significant inter-disciplinary research challenges. This paper presents a study of a simple implementation of adaptive partitioning and discusses implied potential benefits from the perspective of common groups of users within computational science. The study is based on a large set of data derived from experiments including six real-life, multi-time-step adaptive applications from various scientific domains, five complementing and fundamentally different partitioning techniques, a large set of parameters corresponding to a wide spectrum of computing environments, and a flexible cost function that considers the relative impact of multiple partitioning metrics and diverse partitioning objectives. The results show that even a simple implementation of adaptive partitioning can automatically generate results statistically equivalent to the best static partitioning. Thus, it is possible to effectively eliminate the problem of determining the

  10. Selenium accumulation by plants

    PubMed Central

    White, Philip J.

    2016-01-01

    Background Selenium (Se) is an essential mineral element for animals and humans, which they acquire largely from plants. The Se concentration in edible plants is determined by the Se phytoavailability in soils. Selenium is not an essential element for plants, but excessive Se can be toxic. Thus, soil Se phytoavailability determines the ecology of plants. Most plants cannot grow on seleniferous soils. Most plants that grow on seleniferous soils accumulate <100 mg Se kg–1 dry matter and cannot tolerate greater tissue Se concentrations. However, some plant species have evolved tolerance to Se, and commonly accumulate tissue Se concentrations >100 mg Se kg–1 dry matter. These plants are considered to be Se accumulators. Some species can even accumulate Se concentrations of 1000–15 000 mg Se kg–1 dry matter and are called Se hyperaccumulators. Scope This article provides an overview of Se uptake, translocation and metabolism in plants and highlights the possible genetic basis of differences in these between and within plant species. The review focuses initially on adaptations allowing plants to tolerate large Se concentrations in their tissues and the evolutionary origin of species that hyperaccumulate Se. It then describes the variation in tissue Se concentrations between and within angiosperm species and identifies genes encoding enzymes limiting the rates of incorporation of Se into organic compounds and chromosomal loci that might enable the development of crops with greater Se concentrations in their edible portions. Finally, it discusses transgenic approaches enabling plants to tolerate greater Se concentrations in the rhizosphere and in their tissues. Conclusions The trait of Se hyperaccumulation has evolved several times in separate angiosperm clades. The ability to tolerate large tissue Se concentrations is primarily related to the ability to divert Se away from the accumulation of selenocysteine and selenomethionine, which might be incorporated

  11. Differential cadmium accumulation and phytotoxicity in sixteen tobacco cultivars

    SciTech Connect

    Clarke, B.B.; Brennan, E. )

    1989-10-01

    A greenhouse experiment was conducted to determine the effect of plant genotype on cadmium accumulation and phytotoxicity in tobacco. When low levels of CdCl{sub 2} were added to the nutrient solution of 16 tobacco cultivars growing in sand culture, the heavy metal was partitioned in the following order: leaves > roots > stems. Because leaves are the commercial product, this pattern of partitioning is highly undersirable. The concentration of Cd accumulated in the tissues varied with plant genotype and level of Cd treatment. At the 0.25 ppm Cd treatment, a maximum of 127.6 ppm Cd was found in foliage of the Coker-48 variety, and at the 1.0 ppm Cd treatment, a maximum of 382.6 ppm Cd was detected in the foliage of NC-232. None of the Cd-treated tobacco plants exhibited visual foliar symptoms commonly observed in other plant species. A concentration of 0.25 ppm Cd stimulated shoot height, internode length and leaf number but inhibited total dry weight and percent dry weight. Cd phytotoxicity was found to vary with plant genotype and level of Cd treatment but not with the amount of Cd accumulated by the plant.

  12. Measurement of the iodine partition coefficient

    SciTech Connect

    Furrer, M.; Cripps, R.C.; Gubler, R.

    1985-08-01

    The hydrolysis of iodine is complicated because it involves a number of species that differ considerably in their individual volatilities. Large uncertainties exist in the thermodynamic data of some of the iodine species, especially at temperatures above 25C. Because of this, an experiment was undertaken to measure the partition coefficient under varying physical and chemical conditions. Measurements of P were made for a temperature range of 21 to 113C under well-defined conditions (liquid molar concentration, pH, and redox potential) for inorganic iodine. The experimental results are interpreted with the aid of an analytical model and published thermodynamic data. A good agreement between calculated and measured values was found. The experimental setup allows the determination of very high partition coefficients up to a value of 2.0 X 10W. This is demonstrated by adding cesium-iodide to the fuel pool water of a boiling water reactor.

  13. Number Partitioning via Quantum Adiabatic Computation

    NASA Technical Reports Server (NTRS)

    Smelyanskiy, Vadim N.; Toussaint, Udo; Clancy, Daniel (Technical Monitor)

    2002-01-01

    We study both analytically and numerically the complexity of the adiabatic quantum evolution algorithm applied to random instances of combinatorial optimization problems. We use as an example the NP-complete set partition problem and obtain an asymptotic expression for the minimal gap separating the ground and exited states of a system during the execution of the algorithm. We show that for computationally hard problem instances the size of the minimal gap scales exponentially with the problem size. This result is in qualitative agreement with the direct numerical simulation of the algorithm for small instances of the set partition problem. We describe the statistical properties of the optimization problem that are responsible for the exponential behavior of the algorithm.

  14. Analysis of fractals with combined partition

    NASA Astrophysics Data System (ADS)

    Dedovich, T. G.; Tokarev, M. V.

    2016-03-01

    The space—time properties in the general theory of relativity, as well as the discreteness and non-Archimedean property of space in the quantum theory of gravitation, are discussed. It is emphasized that the properties of bodies in non-Archimedean spaces coincide with the properties of the field of P-adic numbers and fractals. It is suggested that parton showers, used for describing interactions between particles and nuclei at high energies, have a fractal structure. A mechanism of fractal formation with combined partition is considered. The modified SePaC method is offered for the analysis of such fractals. The BC, PaC, and SePaC methods for determining a fractal dimension and other fractal characteristics (numbers of levels and values of a base of forming a fractal) are considered. It is found that the SePaC method has advantages for the analysis of fractals with combined partition.

  15. Dynamic criteria for partitioning and transmutation

    SciTech Connect

    Lu, A.H. )

    1991-11-01

    Because of the slow progress being made in the national geologic repository program, the idea of partitioning and transmuting (P-T) long-lived radionuclides resurfaces as a potential improvement in high-level radioactive waste management. It seems theoretically possible to reduce the overall problems of radioactive waste by repeatedly partitioning and recycling wastes into actinide-free wastes, but there are recognizable difficulties and negative consequences that may overshadow the long-term benefits. This paper addresses some of the criteria that might be used to achieve an optimal P-T concept development, i.e., to minimize the negative short-term impact and to maximize both short-term and long-term benefits.

  16. Partition-DFT on the water dimer.

    PubMed

    Gómez, Sara; Nafziger, Jonathan; Restrepo, Albeiro; Wasserman, Adam

    2017-02-21

    As is well known, the ground-state symmetry group of the water dimer switches from its equilibrium Cs-character to C2h-character as the distance between the two oxygen atoms of the dimer decreases below RO-O∼2.5 Å. For a range of RO-O between 1 and 5 Å, and for both symmetries, we apply Partition Density Functional Theory (PDFT) to find the unique monomer densities that sum to the correct dimer densities while minimizing the sum of the monomer energies. We calculate the work involved in deforming the isolated monomer densities and find that it is slightly larger for the Cs geometry for all RO-O. We discuss how the PDFT densities and the corresponding partition potentials support the orbital-interaction picture of hydrogen-bond formation.

  17. Bipartite graph partitioning and data clustering

    SciTech Connect

    Zha, Hongyuan; He, Xiaofeng; Ding, Chris; Gu, Ming; Simon, Horst D.

    2001-05-07

    Many data types arising from data mining applications can be modeled as bipartite graphs, examples include terms and documents in a text corpus, customers and purchasing items in market basket analysis and reviewers and movies in a movie recommender system. In this paper, the authors propose a new data clustering method based on partitioning the underlying biopartite graph. The partition is constructed by minimizing a normalized sum of edge weights between unmatched pairs of vertices of the bipartite graph. They show that an approximate solution to the minimization problem can be obtained by computing a partial singular value decomposition (SVD) of the associated edge weight matrix of the bipartite graph. They point out the connection of their clustering algorithm to correspondence analysis used in multivariate analysis. They also briefly discuss the issue of assigning data objects to multiple clusters. In the experimental results, they apply their clustering algorithm to the problem of document clustering to illustrate its effectiveness and efficiency.

  18. Interaction of 7-n-alkoxycoumarins with cytochrome P-450(2) and their partitioning into liposomal membranes. Assessment of methods for determination of membrane partition coefficients.

    PubMed Central

    Vermeir, M; Boens, N; Heirwegh, K P

    1992-01-01

    A study was made of the binding of 7-ethoxy-, 7-n-propoxy- and 7-n-pentoxy-coumarin to cytochrome P-450(2) reconstituted into large unilamellar liposomes composed of a mixture of egg L-alpha-phosphatidylcholine, egg phosphatidylethanolamine and dipalmitoyl phosphatidic acid (2:1:0.06, by weight). The apparent spectral dissociation constants Ksapp. increased linearly with increasing proteoliposomal concentration. When both cytochrome P-450(2) and NADPH:cytochrome P-450 reductase were reconstituted into liposomes, the apparent Michaelis constants Kmapp. for O-dealkylation of 7-methoxy-, 7-ethoxy- and 7-n-propoxy-coumarin showed a similar dependence on the proteoliposomal concentration. The results were in accordance with models for kinetic or equilibrium processes in biphasic systems containing membrane-bound catalytic or acceptor sites, in which a linear solute partition in the bilayer membrane is postulated. The methyl, ethyl and n-propyl ether were readily dealkylated. However, the O-dealkylation rate of 7-n-butoxycoumarin was low and became very small for longer alkyl ethers. Both the effective dissociation constants and effective Michaelis constants decreased with elongation of the alkyl side chain of the coumarins. From plots of the apparent dissociation constants and apparent Michaelis constants against the lipid volume fraction of the proteoliposomes, the membrane partition coefficients for several homologues were calculated. When protein-free liposomes were added to 7-n-alkoxycoumarin solutions, the fluorescence intensity of the coumarins decreased and eventually became negligible in the presence of an excess of liposomal material. On the assumption that the overall fluorescence can be ascribed exclusively to the fraction of 7-n-alkoxycoumarin molecules present in the aqueous phase, partition coefficients for liposomal accumulation of the test compounds could be determined directly. For several coumarin ethers, comparable values were derived for the membrane

  19. Partition algebraic design of asynchronous sequential circuits

    NASA Technical Reports Server (NTRS)

    Maki, Gary K.; Chen, Kristen Q.; Gopalakrishnan, Suresh K.

    1993-01-01

    Tracey's Theorem has long been recognized as essential in generating state assignments for asynchronous sequential circuits. This paper shows that partitioning variables derived from Tracey's Theorem also has a significant impact in generating the design equations. Moreover, this theorem is important to the fundamental understanding of asynchronous sequential operation. The results of this work simplify asynchronous logic design. Moreover, detection of safe circuits is made easier.

  20. Partitioning coefficients between olivine and silicate melts

    NASA Astrophysics Data System (ADS)

    Bédard, J. H.

    2005-08-01

    Variation of Nernst partition coefficients ( D) between olivine and silicate melts cannot be neglected when modeling partial melting and fractional crystallization. Published natural and experimental olivine/liquidD data were examined for covariation with pressure, temperature, olivine forsterite content, and melt SiO 2, H 2O, MgO and MgO/MgO + FeO total. Values of olivine/liquidD generally increase with decreasing temperature and melt MgO content, and with increasing melt SiO 2 content, but generally show poor correlations with other variables. Multi-element olivine/liquidD profiles calculated from regressions of D REE-Sc-Y vs. melt MgO content are compared to results of the Lattice Strain Model to link melt MgO and: D0 (the strain compensated partition coefficient), EM3+ (Young's Modulus), and r0 (the size of the M site). Ln D0 varies linearly with Ln MgO in the melt; EM3+ varies linearly with melt MgO, with a dog-leg at ca. 1.5% MgO; and r0 remains constant at 0.807 Å. These equations are then used to calculate olivine/liquidD for these elements using the Lattice Strain Model. These empirical parameterizations of olivine/liquidD variations yield results comparable to experimental or natural partitioning data, and can easily be integrated into existing trace element modeling algorithms. The olivine/liquidD data suggest that basaltic melts in equilibrium with pure olivine may acquire small negative Ta-Hf-Zr-Ti anomalies, but that negative Nb anomalies are unlikely to develop. Misfits between results of the Lattice Strain Model and most light rare earth and large ion lithophile partitioning data suggest that kinetic effects may limit the lower value of D for extremely incompatible elements in natural situations characterized by high cooling/crystallization rates.

  1. Pure Partition Functions of Multiple SLEs

    NASA Astrophysics Data System (ADS)

    Kytölä, Kalle; Peltola, Eveliina

    2016-08-01

    Multiple Schramm-Loewner Evolutions (SLE) are conformally invariant random processes of several curves, whose construction by growth processes relies on partition functions—Möbius covariant solutions to a system of second order partial differential equations. In this article, we use a quantum group technique to construct a distinguished basis of solutions, which conjecturally correspond to the extremal points of the convex set of probability measures of multiple SLEs.

  2. Hardware Index to Set Partition Converter

    DTIC Science & Technology

    2013-01-01

    www.jstatsoft.org/ 8. Knuth , D.E.: Volume 4 Generating all combinations and permutations. In: The Art of Computer Programming, Fascicle 3. Addison...especially requires high-speed enumeration of partitions. Recent research in computational molecular biology has shown the importance of par- titions...speed generation of combinations, as well as the generation of random combina- tions for use in reconfigurable computers . It can also be viewed as a

  3. Environment Partitioning and Reactivity of Polybrominated Diphenylethers

    NASA Technical Reports Server (NTRS)

    Hua, Inez; Iraci, Laura T.; Jafvert, Chad; Bezares-Cruz, Juan

    2004-01-01

    Polybrominated diphenyl ethers (PBDEs) are an important class of flame retardants. Annual global demand for these compounds was over 67,000 metric tons in 2001. PBDEs have recently been extensively investigated as environmental contaminants because they have been detected in air, sediment, and tissue samples from urban and remote areas. Important issues include quantifying PBDE partitioning in various environmental compartments, and elucidating transformation pathways. The partitioning of PBDE congeners to aerosols was estimated for 16 sites in the United States, Canada, and Mexico. The aerosol particles were PM2.5, the total suspended particle (TSP) concentration varied between 3.0 - 55.4 micro g/cubic meter, and the organic fraction ranged from 11 - 41%; these data are published values for each site. It is estimated that the largest fraction of each PBDE associated with the aerosol particles occurs in Mexico City, and the smallest fraction in Colorado Plateau. Although the organic fraction in Mexico City is about 60% of that observed in the Colorado Plateau, the TSP is larger by a factor of about 18.5, and it is the difference in TSP that strongly influences the fraction of particle-bound PBDE in this case. PBDE partitioning to PM2.5 particles also varies seasonally because of temperature variations. For the less brominated congeners the percentage that is particle-bound is relatively low, regardless of air temperature. In contrast, the heavier congeners exhibit a significant temperature dependence: as the temperature decreases (fall, winter) the percentage of PBDE that is particle-bound increases. The partitioning calculations complement experimental data indicating that decabromodiphenyl ether (DBDE) dissolved in hexane transforms very rapidly when irradiated with solar light. DBDE is the most highly brominated PBDE congener (10 bromine atoms) and occurs in the commercial formulation which is subject to the largest global demand.

  4. Peptide partitioning properties from direct insertion studies

    SciTech Connect

    Ulmschneider, Martin; Smith, Jeremy C; Ulmschneider, Jakob

    2010-06-01

    Partitioning properties of polypeptides are at the heart of biological membrane phenomena and their precise quantification is vital for ab-initio structure prediction and the accurate simulation of membrane protein folding and function. Recently the cellular translocon machinery has been employed to determine membrane insertion propensities and transfer energetics for a series of polyleucine segments embedded in a carrier sequence. We show here that the insertion propensity, pathway, and transfer energetics into synthetic POPC bilayers can be fully described by direct atomistic peptide partitioning simulations. The insertion probability as a function of peptide length follows two-state Boltzmann statistics, in agreement with the experiments. The simulations expose a systematic offset between translocon-mediated and direct insertion free energies. Compared to the experiment the insertion threshold is shifted toward shorter peptides by 2 leucine residues. The simulations reveal many hitherto unknown atomic-resolution details about the partitioning process and promise to provide a powerful tool for urgently needed calibration of lipid parameters to match experimentally observed peptide transfer energies.

  5. Diversity partitioning during the Cambrian radiation

    PubMed Central

    Na, Lin; Kiessling, Wolfgang

    2015-01-01

    The fossil record offers unique insights into the environmental and geographic partitioning of biodiversity during global diversifications. We explored biodiversity patterns during the Cambrian radiation, the most dramatic radiation in Earth history. We assessed how the overall increase in global diversity was partitioned between within-community (alpha) and between-community (beta) components and how beta diversity was partitioned among environments and geographic regions. Changes in gamma diversity in the Cambrian were chiefly driven by changes in beta diversity. The combined trajectories of alpha and beta diversity during the initial diversification suggest low competition and high predation within communities. Beta diversity has similar trajectories both among environments and geographic regions, but turnover between adjacent paleocontinents was probably the main driver of diversification. Our study elucidates that global biodiversity during the Cambrian radiation was driven by niche contraction at local scales and vicariance at continental scales. The latter supports previous arguments for the importance of plate tectonics in the Cambrian radiation, namely the breakup of Pannotia. PMID:25825755

  6. Microbial partitioning to settleable particles in stormwater.

    PubMed

    Characklis, Gregory W; Dilts, Mackenzie J; Simmons, Otto D; Likirdopulos, Christina A; Krometis, Leigh-Anne H; Sobsey, Mark D

    2005-05-01

    The degree to which microbes in the water column associate with settleable particles has important implications for microbial transport in receiving waters, as well as for microbial removal via sedimentation (i.e. detention basins). The partitioning behavior of several bacterial, protozoan and viral indicator organisms is explored in three urban streams under both storm and dry weather conditions. The fraction of organisms associated with settleable particles in stormwater is estimated through use of a centrifugation technique which is calibrated using suspensions of standard particles (e.g., glass, latex). The fraction of organisms associated with settleable particles varies by type of microbe, and the partitioning behavior of each organism generally changes between dry weather and storm conditions. Bacterial indicator organisms (fecal coliforms, Escherichia coli, enterococci) exhibited relatively consistent behavior, with an average of 20-35% of organisms associated with these particles in background samples and 30-55% in storm samples. Clostridium perfringens spores exhibited the highest average level of particle association, with storm values varying from 50% to 70%. Results related to total coliphage partitioning were more variable, with 20-60% associated with particles during storms. These estimates should be valuable in surface water quality modeling efforts, many of which currently assume that all microbes exist as free (unattached) organisms.

  7. Phase partitioning experiment (8-IML-1)

    NASA Technical Reports Server (NTRS)

    Brooks, Donald E.

    1992-01-01

    Phase partitioning is a method of separating biological cells and macromolecules via their differential distribution in two phase aqueous polymer solutions. The ultimate goal of the experiment is to test the hypothesis that the efficiency of separation of closely related cell types, by partitioning in immiscible aqueous phases, will be enhanced in the non-convective environment provided by space. Before a cell separation experiment can be performed, the demixing of immiscible aqueous polymer solutions must be understood and controlled in order to optimize the experimental conditions for a cell separation experiment in the future. The present Phase Partitioning Experiment (PPE) is the third in a series, the first two flew on STS 51-D in Apr. 1985 and STS 26 in Oct. 1988. In those experiments the immiscible aqueous phases demixed spontaneously at different rates, the final disposition being one in which the phase which wetted the container wall surrounded the second phase which formed an 'egg yolk' in the center of the chamber.

  8. Equilibrium Partitioning Sediment Benchmarks (ESBs) for the ...

    EPA Pesticide Factsheets

    This document describes procedures to determine the concentrations of nonionic organic chemicals in sediment interstitial waters. In previous ESB documents, the general equilibrium partitioning (EqP) approach was chosen for the derivation of sediment benchmarks because it accounts for the varying bioavailability of chemicals in different sediments and allows for the incorporation of the appropriate biological effects concentration. This provides for the derivation of benchmarks that are causally linked to the specific chemical, applicable across sediments, and appropriately protective of benthic organisms.  This equilibrium partitioning sediment benchmark (ESB) document was prepared by scientists from the Atlantic Ecology Division, Mid-Continent Ecology Division, and Western Ecology Division, the Office of Water, and private consultants. The document describes procedures to determine the interstitial water concentrations of nonionic organic chemicals in contaminated sediments. Based on these concentrations, guidance is provided on the derivation of toxic units to assess whether the sediments are likely to cause adverse effects to benthic organisms. The equilibrium partitioning (EqP) approach was chosen because it is based on the concentrations of chemical(s) that are known to be harmful and bioavailable in the environment.  This document, and five others published over the last nine years, will be useful for the Program Offices, including Superfund, a

  9. Biogeography of time partitioning in mammals

    PubMed Central

    Bennie, Jonathan J.; Duffy, James P.; Inger, Richard; Gaston, Kevin J.

    2014-01-01

    Many animals regulate their activity over a 24-h sleep–wake cycle, concentrating their peak periods of activity to coincide with the hours of daylight, darkness, or twilight, or using different periods of light and darkness in more complex ways. These behavioral differences, which are in themselves functional traits, are associated with suites of physiological and morphological adaptations with implications for the ecological roles of species. The biogeography of diel time partitioning is, however, poorly understood. Here, we document basic biogeographic patterns of time partitioning by mammals and ecologically relevant large-scale patterns of natural variation in “illuminated activity time” constrained by temperature, and we determine how well the first of these are predicted by the second. Although the majority of mammals are nocturnal, the distributions of diurnal and crepuscular species richness are strongly associated with the availability of biologically useful daylight and twilight, respectively. Cathemerality is associated with relatively long hours of daylight and twilight in the northern Holarctic region, whereas the proportion of nocturnal species is highest in arid regions and lowest at extreme high altitudes. Although thermal constraints on activity have been identified as key to the distributions of organisms, constraints due to functional adaptation to the light environment are less well studied. Global patterns in diversity are constrained by the availability of the temporal niche; disruption of these constraints by the spread of artificial lighting and anthropogenic climate change, and the potential effects on time partitioning, are likely to be critical influences on species’ future distributions. PMID:25225371

  10. Biogeography of time partitioning in mammals.

    PubMed

    Bennie, Jonathan J; Duffy, James P; Inger, Richard; Gaston, Kevin J

    2014-09-23

    Many animals regulate their activity over a 24-h sleep-wake cycle, concentrating their peak periods of activity to coincide with the hours of daylight, darkness, or twilight, or using different periods of light and darkness in more complex ways. These behavioral differences, which are in themselves functional traits, are associated with suites of physiological and morphological adaptations with implications for the ecological roles of species. The biogeography of diel time partitioning is, however, poorly understood. Here, we document basic biogeographic patterns of time partitioning by mammals and ecologically relevant large-scale patterns of natural variation in "illuminated activity time" constrained by temperature, and we determine how well the first of these are predicted by the second. Although the majority of mammals are nocturnal, the distributions of diurnal and crepuscular species richness are strongly associated with the availability of biologically useful daylight and twilight, respectively. Cathemerality is associated with relatively long hours of daylight and twilight in the northern Holarctic region, whereas the proportion of nocturnal species is highest in arid regions and lowest at extreme high altitudes. Although thermal constraints on activity have been identified as key to the distributions of organisms, constraints due to functional adaptation to the light environment are less well studied. Global patterns in diversity are constrained by the availability of the temporal niche; disruption of these constraints by the spread of artificial lighting and anthropogenic climate change, and the potential effects on time partitioning, are likely to be critical influences on species' future distributions.

  11. On bottleneck partitioning k-ary n-cubes

    NASA Technical Reports Server (NTRS)

    Nicol, David M.; Mao, Weizhen

    1994-01-01

    Graph partitioning is a topic of extensive interest, with applications to parallel processing. In this context graph nodes typically represent computation, and edges represent communication. One seeks to distribute the workload by partitioning the graph so that every processor has approximately the same workload, and the communication cost (measured as a function of edges exposed by the partition) is minimized. Measures of partition quality vary; in this paper we consider a processor's cost to be the sum of its computation and communication costs, and consider the cost of a partition to be the bottleneck, or maximal processor cost induced by the partition. For a general graph the problem of finding an optimal partitioning is intractable. In this paper we restrict our attention to the class of k-art n-cube graphs with uniformly weighted nodes. Given mild restrictions on the node weight and number of processors, we identify partitions yielding the smallest bottleneck. We also demonstrate by example that some restrictions are necessary for the partitions we identify to be optimal. In particular, there exist cases where partitions that evenly partition nodes need not be optimal.

  12. Accumulation of contaminants of emerging concern in food crops-part 2: Plant distribution.

    PubMed

    Hyland, Katherine C; Blaine, Andrea C; Higgins, Christopher P

    2015-10-01

    Arid agricultural regions often turn to using treated wastewater (reclaimed water) to irrigate food crops. Concerns arise, however, when considering the potential for persistent contaminants of emerging concern to accumulate into plants intended for human consumption. The present study examined the accumulation of a suite of 9 contaminants of emerging concern into 2 representative food crops, lettuce and strawberry, following uptake via the roots and subsequent distribution to other plant tissues. Calculating accumulation metrics (concentration factors) allowed for comparison of the compartmental affinity of each chemical for each plant tissue compartment. The root concentration factor was found to exhibit a positive linear correlation with the pH-adjusted octanol-water partition coefficient (DOW ) for the target contaminants of emerging concern. Coupled with the concentration-dependent accumulation observed in the roots, this result implies that accumulation of these contaminants of emerging concern into plant roots is driven by passive partitioning. Of the contaminants of emerging concern examined, nonionizable contaminants, such as triclocarban, carbamazepine, and organophosphate flame retardants displayed the greatest potential for translocation from the roots to above-ground plant compartments. In particular, the organophosphate flame retardants displayed increasing affinity for shoots and fruits with decreasing size/octanol-water partition coefficient (KOW ). Cationic diphenhydramine and anionic sulfamethoxazole, once transported to the shoots of the strawberry plant, demonstrated the greatest potential of the contaminants examined to be then carried to the edible fruit portion.

  13. Polymers as Reference Partitioning Phase: Polymer Calibration for an Analytically Operational Approach To Quantify Multimedia Phase Partitioning.

    PubMed

    Gilbert, Dorothea; Witt, Gesine; Smedes, Foppe; Mayer, Philipp

    2016-06-07

    Polymers are increasingly applied for the enrichment of hydrophobic organic chemicals (HOCs) from various types of samples and media in many analytical partitioning-based measuring techniques. We propose using polymers as a reference partitioning phase and introduce polymer-polymer partitioning as the basis for a deeper insight into partitioning differences of HOCs between polymers, calibrating analytical methods, and consistency checking of existing and calculation of new partition coefficients. Polymer-polymer partition coefficients were determined for polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs) by equilibrating 13 silicones, including polydimethylsiloxane (PDMS) and low-density polyethylene (LDPE) in methanol-water solutions. Methanol as cosolvent ensured that all polymers reached equilibrium while its effect on the polymers' properties did not significantly affect silicone-silicone partition coefficients. However, we noticed minor cosolvent effects on determined polymer-polymer partition coefficients. Polymer-polymer partition coefficients near unity confirmed identical absorption capacities of several PDMS materials, whereas larger deviations from unity were indicated within the group of silicones and between silicones and LDPE. Uncertainty in polymer volume due to imprecise coating thickness or the presence of fillers was identified as the source of error for partition coefficients. New polymer-based (LDPE-lipid, PDMS-air) and multimedia partition coefficients (lipid-water, air-water) were calculated by applying the new concept of a polymer as reference partitioning phase and by using polymer-polymer partition coefficients as conversion factors. The present study encourages the use of polymer-polymer partition coefficients, recognizing that polymers can serve as a linking third phase for a quantitative understanding of equilibrium partitioning of HOCs between any two phases.

  14. Solid lubricants

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1991-01-01

    The state of knowledge of solid lubricants is reviewed. The results of research on solid lubricants from the 1940's to the present are presented from a historical perspective. Emphasis is placed largely, but not exclusively, on work performed at NASA Lewis Research Center with a natural focus on aerospace applications. However, because of the generic nature of the research, the information presented in this review is applicable to most areas where solid lubricant technology is useful.

  15. Solid lubricants

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1993-01-01

    The state of knowledge of solid lubricants is reviewed. The results of research on solid lubricants from the 1940's to the present are presented from a historical perspective. Emphasis is placed largely, but not exclusively, on work performed at NASA Lewis Research Center with a natural focus on aerospace applications. However, because of the generic nature of the research, the information presented in this review is applicable to most areas where solid lubricant technology is useful.

  16. Subcellular Partitioning and Intramacrophage Selectivity of Antimicrobial Compounds against Mycobacterium tuberculosis.

    PubMed

    Schump, Michael D; Fox, Douglas M; Bertozzi, Carolyn R; Riley, Lee W

    2017-03-01

    The efficacy of antimicrobial drugs against Mycobacterium tuberculosis, an intracellular bacterial pathogen, is generally first established by testing compounds against bacteria in axenic culture. However, inside infected macrophages, bacteria encounter an environment which differs substantially from broth culture and are subject to important host-dependent pharmacokinetic phenomena which modulate drug activity. Here, we describe how pH-dependent partitioning drives asymmetric antimicrobial drug distribution in M. tuberculosis-infected macrophages. Specifically, weak bases with moderate activity against M. tuberculosis (fluoxetine, sertraline, and dibucaine) were shown to accumulate intracellularly due to differential permeability and relative abundance of their ionized and nonionized forms. Nonprotonatable analogs of the test compounds did not show this effect. Neutralization of acidic organelles directly with ammonium chloride or indirectly with bafilomycin A1 partially abrogated the growth restriction of these drugs. Using high-performance liquid chromatography, we quantified the degree of accumulation and reversibility upon acidic compartment neutralization in macrophages and observed that accumulation was greater in infected than in uninfected macrophages. We further demonstrate that the efficacy of a clinically used compound, clofazimine, is augmented by pH-based partitioning in a macrophage infection model. Because the parameters which govern this effect are well understood and are amenable to chemical modification, this knowledge may enable the rational development of more effective antibiotics against tuberculosis.

  17. Safety-Critical Partitioned Software Architecture: A Partitioned Software Architecture for Robotic

    NASA Technical Reports Server (NTRS)

    Horvath, Greg; Chung, Seung H.; Cilloniz-Bicchi, Ferner

    2011-01-01

    The flight software on virtually every mission currently managed by JPL has several major flaws that make it vulnerable to potentially fatal software defects. Many of these problems can be addressed by recently developed partitioned operating systems (OS). JPL has avoided adopting a partitioned operating system on its flight missions, primarily because doing so would require significant changes in flight software design, and the risks associated with changes of that magnitude cannot be accepted by an active flight project. The choice of a partitioned OS can have a dramatic effect on the overall system and software architecture, allowing for realization of benefits far beyond the concerns typically associated with the choice of OS. Specifically, we believe that a partitioned operating system, when coupled with an appropriate architecture, can provide a strong infrastructure for developing systems for which reusability, modifiability, testability, and reliability are essential qualities. By adopting a partitioned OS, projects can gain benefits throughout the entire development lifecycle, from requirements and design, all the way to implementation, testing, and operations.

  18. Shear Stress Partitioning in Large Patches of Roughness in the Atmospheric Inertial Sublayer

    NASA Technical Reports Server (NTRS)

    Gillies, John A.; Nickling, William G.; King, James

    2007-01-01

    Drag partition measurements were made in the atmospheric inertial sublayer for six roughness configurations made up of solid elements in staggered arrays of different roughness densities. The roughness was in the form of a patch within a large open area and in the shape of an equilateral triangle with 60 m long sides. Measurements were obtained of the total shear stress (tau) acting on the surfaces, the surface shear stress on the ground between the elements (tau(sub S)) and the drag force on the elements for each roughness array. The measurements indicated that tau(sub S) quickly reduced near the leading edge of the roughness compared with tau, and a tau(sub S) minimum occurs at a normalized distance (x/h, where h is element height) of approx. -42 (downwind of the roughness leading edge is negative), then recovers to a relatively stable value. The location of the minimum appears to scale with element height and not roughness density. The force on the elements decreases exponentially with normalized downwind distance and this rate of change scales with the roughness density, with the rate of change increasing as roughness density increases. Average tau(sub S): tau values for the six roughness surfaces scale predictably as a function of roughness density and in accordance with a shear stress partitioning model. The shear stress partitioning model performed very well in predicting the amount of surface shear stress, given knowledge of the stated input parameters for these patches of roughness. As the shear stress partitioning relationship within the roughness appears to come into equilibrium faster for smaller roughness element sizes it would also appear the shear stress partitioning model can be applied with confidence for smaller patches of smaller roughness elements than those used in this experiment.

  19. Accumulative Tritium Transfer from Water into Biosystems

    SciTech Connect

    Baumgaertner, Franz

    2005-07-15

    The energy balance of hydrogen isotopes in H bonds of water and biomolecules results in accumulative tritium transfer from water into biomolecules. Tests of DNA dissolved in tritiated water and of maize or barley hydroponically grown in tritiated water confirm the increase. The primary hydration shell of DNA shows an accumulation factor of {approx}1.4, and the exchangeable hydrogens inside DNA show {approx}2. Logistic growth analyses of maize and barley reveal the intrinsic growth rates of tritium 1.3 and 1.2 times larger than that of hydrogen. The higher rate of tritium than hydrogen incorporation in solid biomatter is caused by the hydration shells, which constitute an intrinsic component of biomolecules.

  20. Investigating the Partitioning of Inorganic Elements Consumed by Humans between the Various Fractions of Human Wastes: An Alternative Approach

    NASA Technical Reports Server (NTRS)

    Wignarajah, Kanapathipillai; Pisharody, Suresh; Fisher, John W.

    2003-01-01

    The elemental composition of food consumed by astronauts is well defined. The major elements carbon, hydrogen, oxygen, nitrogen and sulfur are taken up in large amounts and these are often associated with the organic fraction (carbohydrates, proteins, fats etc) of human tissue. On the other hand, a number of the elements are located in the extracellular fluids and can be accounted for in the liquid and solid waste fraction of humans. These elements fall into three major categories - cationic macroelements (e.g. Ca, K, Na, Mg and Si), anionic macroelements (e.g. P, S and Cl and 17 essential microelements, (e.g. Fe, Mn, Cr, Co, Cu, Zn, Se and Sr). When provided in the recommended concentrations to an adult healthy human, these elements should not normally accumulate in humans and will eventually be excreted in the different human wastes. Knowledge of the partitioning of these elements between the different human waste fractions is important in understanding (a) developing waste separation technologies, (b) decision-making on how these elements can be recovered for reuse in space habitats, and (c) to developing the processors for waste management. Though considerable literature exists on these elements, there is a lack of understanding and often conflicting data. Two major reasons for these problems include the lack of controlled experimental protocols and the inherently large variations between human subjects (Parker and Gallagher, 1988). We have used the existing knowledge of human nutrition and waste from the available literature and NASA documentation to build towards a consensus to typify and chemically characterize the various human wastes. It is our belief, that this could be a building block towards integrating a human life support and waste processing in a closed system.

  1. Carbon-nitrogen ratio and in vitro assimilate partitioning patterns in Cyrtanthus guthrieae L.

    PubMed

    Ncube, Bhekumthetho; Finnie, Jeffrey F; Van Staden, Johannes

    2014-01-01

    In response to variations in nutritional composition of the growth medium, plants often adjust their metabolism and progressively alter their growth patterns. Carbon (C) and nitrogen (N) constitute the major plant nutritional components influencing plant growth and development patterns. This study examined the growth dynamics and patterns of assimilate partitioning to primary and secondary metabolites in response to varying levels and combinations of C and N in the culture media of Cyrtanthus guthrieae. In vitro callus-derived C. guthrieae plantlets were cultured on solid Murashige and Skoog (MS) media with different concentrations and combinations of C and N. Relative growth rate (RGR) increased proportionally with an increase in C concentrations up to 88 mM sucrose (0.58 d(-1)) beyond which it was hardly influenced by further increases in C. Growth was also significantly favoured in media with high concentrations of N at all C concentrations tested. In C-limited media regimes with growth saturating N conditions, alkaloid accumulation became favoured while polyphenol content increased with an increase in C levels in the medium, a characteristic pattern that appeared to be less influenced by the amount of N. Of the primary metabolites, only proteins showed small significant variations across different media treatments, with starch and soluble sugars increasing proportionately with C levels. In the medium with a high sucrose concentration (175 mM), soluble sugars, amino acids and polyphenols increased markedly, possibly as an adaptive response to the reduced osmotic potential in the media and/or a storage mechanism for excess C and N reserves in the media. From a medicinal perspective, with regard to polyphenolic compounds in C. guthrieae, growth medium conditions that allow for high levels of C pools in the tissue would thus be favourable for the enhanced synthesis of this group of compounds. The medium conditions with 175 mM sucrose and 10.3 mM NH4NO3 gave the

  2. Heat exchanger-accumulator

    DOEpatents

    Ecker, Amir L.

    1980-01-01

    What is disclosed is a heat exchanger-accumulator for vaporizing a refrigerant or the like, characterized by an upright pressure vessel having a top, bottom and side walls; an inlet conduit eccentrically and sealingly penetrating through the top; a tubular overflow chamber disposed within the vessel and sealingly connected with the bottom so as to define an annular outer volumetric chamber for receiving refrigerant; a heat transfer coil disposed in the outer volumetric chamber for vaporizing the liquid refrigerant that accumulates there; the heat transfer coil defining a passageway for circulating an externally supplied heat exchange fluid; transferring heat efficiently from the fluid; and freely allowing vaporized refrigerant to escape upwardly from the liquid refrigerant; and a refrigerant discharge conduit penetrating sealingly through the top and traversing substantially the length of the pressurized vessel downwardly and upwardly such that its inlet is near the top of the pressurized vessel so as to provide a means for transporting refrigerant vapor from the vessel. The refrigerant discharge conduit has metering orifices, or passageways, penetrating laterally through its walls near the bottom, communicating respectively interiorly and exteriorly of the overflow chamber for controllably carrying small amounts of liquid refrigerant and oil to the effluent stream of refrigerant gas.

  3. High dimensional data clustering by partitioning the hypergraphs using dense subgraph partition

    NASA Astrophysics Data System (ADS)

    Sun, Xili; Tian, Shoucai; Lu, Yonggang

    2015-12-01

    Due to the curse of dimensionality, traditional clustering methods usually fail to produce meaningful results for the high dimensional data. Hypergraph partition is believed to be a promising method for dealing with this challenge. In this paper, we first construct a graph G from the data by defining an adjacency relationship between the data points using Shared Reverse k Nearest Neighbors (SRNN). Then a hypergraph is created from the graph G by defining the hyperedges to be all the maximal cliques in the graph G. After the hypergraph is produced, a powerful hypergraph partitioning method called dense subgraph partition (DSP) combined with the k-medoids method is used to produce the final clustering results. The proposed method is evaluated on several real high-dimensional datasets, and the experimental results show that the proposed method can improve the clustering results of the high dimensional data compared with applying k-medoids method directly on the original data.

  4. A brief history of partitions of numbers, partition functions and their modern applications

    NASA Astrophysics Data System (ADS)

    Debnath, Lokenath

    2016-04-01

    'Number rules the universe.' The Pythagoras 'If you wish to forsee the future of mathematics our course is to study the history and present conditions of the science.' Henri Poincaré 'The primary source (Urqell) of all mathematics are integers.' Hermann Minkowski This paper is written to commemorate the centennial anniversary of the Mathematical Association of America. It deals with a short history of different kinds of natural numbers including triangular, square, pentagonal, hexagonal and k-gonal numbers, and their simple properties and their geometrical representations. Included are Euclid's and Pythagorean's main contributions to elementary number theory with the main contents of the Euclid Elements of the 13-volume masterpiece of mathematical work. This is followed by Euler's new discovery of the additive number theory based on partitions of numbers. Special attention is given to many examples, Euler's theorems on partitions of numbers with geometrical representations of Ferrers' graphs, Young's diagrams, Lagrange's four-square theorem and the celebrated Waring problem. Included are Euler's generating functions for the partitions of numbers, Euler's pentagonal number theorem, Gauss' triangular and square number theorems and the Jacobi triple product identity. Applications of the theory of partitions of numbers to different statistics such as the Bose- Einstein, Fermi- Dirac, Gentile, and Maxwell- Boltzmann statistics are briefly discussed. Special attention is given to pedagogical information through historical approach to number theory so that students and teachers at the school, college and university levels can become familiar with the basic concepts of partitions of numbers, partition functions and their modern applications, and can pursue advanced study and research in analytical and computational number theory.

  5. Chemotaxis toward phytoplankton drives organic matter partitioning among marine bacteria

    PubMed Central

    Smriga, Steven; Fernandez, Vicente I.; Mitchell, James G.; Stocker, Roman

    2016-01-01

    The microenvironment surrounding individual phytoplankton cells is often rich in dissolved organic matter (DOM), which can attract bacteria by chemotaxis. These “phycospheres” may be prominent sources of resource heterogeneity in the ocean, affecting the growth of bacterial populations and the fate of DOM. However, these effects remain poorly quantified due to a lack of quantitative ecological frameworks. Here, we used video microscopy to dissect with unprecedented resolution the chemotactic accumulation of marine bacteria around individual Chaetoceros affinis diatoms undergoing lysis. The observed spatiotemporal distribution of bacteria was used in a resource utilization model to map the conditions under which competition between different bacterial groups favors chemotaxis. The model predicts that chemotactic, copiotrophic populations outcompete nonmotile, oligotrophic populations during diatom blooms and bloom collapse conditions, resulting in an increase in the ratio of motile to nonmotile cells and in the succession of populations. Partitioning of DOM between the two populations is strongly dependent on the overall concentration of bacteria and the diffusivity of different DOM substances, and within each population, the growth benefit from phycospheres is experienced by only a small fraction of cells. By informing a DOM utilization model with highly resolved behavioral data, the hybrid approach used here represents a new path toward the elusive goal of predicting the consequences of microscale interactions in the ocean. PMID:26802122

  6. A method for partitioning cadmium bioaccumulated in small aquatic organisms

    SciTech Connect

    Siriwardena, S.N.; Rana, K.J.; Baird, D.J.

    1995-09-01

    A series of laboratory experiments was conducted to evaluate bioaccumulation and surface adsorption of aqueous cadmium (Cd) by sac-fry of the African tilapia Oreochromis niloticus. In the first experiment, the design consisted of two cadmium treatments: 15 {micro}g Cd{center_dot}L{sup {minus}1} in dilution water and a Cd-ethylenediaminetetraacetic acid (Cd-EDTA) complex at 15 {micro}m{center_dot}L{sup {minus}1}, and a water-only control. There were five replicates per treatment and 40 fish per replicate. It was found that EDTA significantly reduced the bioaccumulation of cadmium by tilapia sac-fry by 34%. Based on the results, a second experiment was conducted to evaluate four procedures: a no-rinse control; rinsing in EDTA; rinsing in distilled water; and rinsing in 5% nitric acid, for removing surface-bound Cd from exposed sac-fry. In this experiment, 30 fish in each of five replicates were exposed to 15 {micro}g Cd{center_dot}L{sup {minus}1} for 72 h, processed through the rinse procedures, and analyzed for total Cd. The EDTA rinse treatment significantly reduced (p<0.05) Cd concentrations of the exposed fish relative to those receiving no rinse. It was concluded that the EDTA rinse technique may be useful in studies evaluating the partitioning of surface-bound and accumulated cadmium in small aquatic organisms.

  7. Dry matter and energy partitioning in plants under climatic stress

    SciTech Connect

    Bolhar-Nordenkampf, H.R.; Postl, W.F.; Meister, M.H.; Ledl, D.; Nemeth, K.; Ludlow, M.M.

    1996-12-31

    During ontogenesis plants distribute assimilates quite differently among their organs depending on the environmental conditions. In case of high sink capacity energetically cheap storing compounds such as carbohydrates and/or organic acids are formed, whereas during periods with low demand proteins and lipids may be accumulated. Besides ontogenesis, drought and increased CO{sub 2} are able to modify sink capacity and by this transients in the partitioning pattern of carbon are induced. Plants, well adapted to several dry seasons during the year are able to allocate carbon predominantly to below ground organs. During this period many leaves become senescent. In any case stems and remaining green leaves will loose dry matter and energy. With 80% of plants under investigation CO{sub 2} enrichment was shown to induce an enforced allocation of carbon to below ground organs. Roots and Rhizomes, beets and tubers act as a sink for the additionally fixed carbon. It was demonstrated that sink capacity is controlling photosynthetic activity. With respect to agricultural production, to ecosystems and to single plants, climatic change will modify productivity and plants distribution pattern as a consequence of quite different metabolic changes. These responses are depending on the effect of natural and anthropogenic stress factors on the use of enhanced CO{sub 2} and on the allocation of additionally formed assimilates.

  8. Photosynthate Partitioning and Fermentation in Hot Spring Microbial Mat Communities

    PubMed Central

    Nold, S. C.; Ward, D. M.

    1996-01-01

    Patterns of (sup14)CO(inf2) incorporation into molecular components of the thermophilic cyanobacterial mat communities inhabiting hot springs located in Yellowstone National Park and Synechococcus sp. strain C1 were investigated. Exponentially growing Synechococcus sp. strain C1 partitioned the majority of incorporated (sup14)CO(inf2) into protein, low-molecular-weight metabolites, and lipid fractions (45, 22, and 18% of total incorporated carbon, respectively). In contrast, mat cores from various hot springs predominantly accumulated polyglucose during periods of illumination (between 77 and 85% of total incorporated (sup14)CO(inf2)). Although photosynthetically active, mat photoautotrophs do not appear to be rapidly growing, since we also detected only limited synthesis of macromolecules associated with growth (i.e., protein and rRNA). To test the hypothesis that polysaccharide reserves are fermented in situ under the dark anaerobic conditions cyanobacterial mats experience at night, mat cores were prelabeled with (sup14)CO(inf2) under illuminated conditions and then transferred to dark anaerobic conditions. Radiolabel in the polysaccharide fraction decreased by 74.7% after 12 h, of which 58.5% was recovered as radiolabeled acetate, CO(inf2), and propionate. These results indicate tightly coupled carbon fixation and fermentative processes and the potential for significant transfer of carbon from primary producers to heterotrophic members of these cyanobacterial mat communities. PMID:16535472

  9. Chemotaxis toward phytoplankton drives organic matter partitioning among marine bacteria.

    PubMed

    Smriga, Steven; Fernandez, Vicente I; Mitchell, James G; Stocker, Roman

    2016-02-09

    The microenvironment surrounding individual phytoplankton cells is often rich in dissolved organic matter (DOM), which can attract bacteria by chemotaxis. These "phycospheres" may be prominent sources of resource heterogeneity in the ocean, affecting the growth of bacterial populations and the fate of DOM. However, these effects remain poorly quantified due to a lack of quantitative ecological frameworks. Here, we used video microscopy to dissect with unprecedented resolution the chemotactic accumulation of marine bacteria around individual Chaetoceros affinis diatoms undergoing lysis. The observed spatiotemporal distribution of bacteria was used in a resource utilization model to map the conditions under which competition between different bacterial groups favors chemotaxis. The model predicts that chemotactic, copiotrophic populations outcompete nonmotile, oligotrophic populations during diatom blooms and bloom collapse conditions, resulting in an increase in the ratio of motile to nonmotile cells and in the succession of populations. Partitioning of DOM between the two populations is strongly dependent on the overall concentration of bacteria and the diffusivity of different DOM substances, and within each population, the growth benefit from phycospheres is experienced by only a small fraction of cells. By informing a DOM utilization model with highly resolved behavioral data, the hybrid approach used here represents a new path toward the elusive goal of predicting the consequences of microscale interactions in the ocean.

  10. Impact of sediment partitioning methods on environmental safety assessment of surfactants

    SciTech Connect

    Orth, R.G.; Powell, R.L.; Kutey, G.; Kimerle, R.A. )

    1995-02-01

    Selection of laboratory methods for partitioning and toxicity tests of sediments has a significant impact on interpretation of aquatic safety of surfactants. This is the case for the assessment of the sediment toxicity of C[sub 12] linear alkylbenzene sulfonates, LAS. In this study, the batch-equilibrium partition coefficient (K[sub d]) was measured as a function of organic carbon, cation exchange capacity, and quantity of sediments. The quantity of sediment was varied from a low of 5 g per 1,000 ml of water to a level of 500 g to 500 ml of water. The measured K[sub d] decreased by an order of magnitude when the ratio of water to sediments increased to 1:1, and as a consequence of this observation, LAS on suspended solids was included in the quantitation of LAS in the water phase. When measured K[sub d] values were then used to predict the toxicity (based on known aquatic toxicity concentrations of LAS using Ceriodaphnia dubia), LAS was calculated to be an order of magnitude less toxic by the low-solids test compared to the high-solids test system. This work reaffirms that selection of a laboratory test to assess environmental safety must be made on the basis of its correlation to the real-world behavior of the surfactant.

  11. Impact of Solvents Treatment on the Wettability of Froth Solids

    NASA Astrophysics Data System (ADS)

    Yang, Fan

    The purpose of this study is to investigate the impact of solvent addition to bitumen froth on the wettability of froth solids. The wettability of solids determines the transportation/partitioning of the solids between phases, which in turn affects the solids and water rejection in a Clark hot water extraction process (CHWE). The impact of solvents treatment on the wettability of froth solids was studied using both a model system and a real bitumen froth system. The vulnerabilities of four kinds of model minerals to hydrocarbon contamination/wettability alteration in different solvents were compared and discussed by considering solvent composition and mineral types. The wettability of solids extracted from the industrial froth using different solvents was also compared. The XRD analysis on these solids confirmed the partitioning behavior of solids observed in model solids system. The results from this study indicate that the composition of paraffinic/aromatic solvent in an industrial froth treatment process could be tailor-optimized to achieve a better solids/water rejection.

  12. Experimental Partitioning of As and SB Among Metal, Troilite, Schreibersite, Barringerite, and Metallic Liquid

    NASA Astrophysics Data System (ADS)

    Jones, J. H.; Casanova, I.

    1993-07-01

    We have performed a series of experiments to evaluate the behaviors of As and Sb in metallic systems. Because of the reputed chalcophile nature of these elements, we wrongly anticipated that they would follow S and that, compared to the Fe-X systems [1], (solid metal/liquid metal) partition coefficients would be considerably lower in S-bearing systems. Experimental and Analytical: Experiments were performed in sealed silica tubes as in [2]. Starting materials were high-purity metals, natural pyrite, and natural stibnite. Charges were doped either with As or Sb. Experiments were held at either 950 degrees C for six days or 1250 degrees C for three days. Typical experimental assemblages consisted either of taenite and coexisting Fe-Ni-S-X liquid (1250 degrees and 950 degrees C) or an assemblage of troilite, schreibersite, and Fe-Ni-S-P-X liquid (950 degrees C). The schreibersite-bearing, As-doped charge also contained barringerite (Fe,Ni)2P. Charges were mounted in epoxy, polished, and analyzed using a Cameca SX-50 electron microprobe and standard techniques. Results: Phases appeared homogeneous. Our results, along with partition coefficients inferred for the S-free system, are given in Table 1. Table 1 appears here in the hard copy. Discussion: Our results indicate that As behaves as a siderophile element at low temperatures, very analogous to Au. While the siderophility of Sb increases with decreasing temperature, it remains incompatible in solid metal. In this regard Sb is unique. Both As and Sb are very incompatible in troilite. Arsenic is weakly incompatible in schreibersite and strongly compatible in barringerite. Nickel shows no preference for either phosphide. Nickel partition coefficients for metal and schreibersite are similar to those measured previously [3]. On a lnD vs. ln(1-2 alpha X(S)) diagram [4], the data for Sb and As subparallel each other, indicating similar dependencies on S, despite their very different partition coefficients. Arsenic behaves

  13. Boron, beryllium, and lithium, partitioning in olivine

    SciTech Connect

    Neroda, Elizabeth

    1996-05-01

    A one atmosphere experimental study was performed to determine the mineral/melt partition coefficients for B, Be, and Li in forsteritic olivine. Two compositions were chosen along the 1350{degrees}C isotherm, 1b (Fo{sub 17.3} Ab{sub 82.7} An{sub 0} by weight) and 8c (Fo{sub 30} Ab{sub 23.3} An{sub 47.8}, by weight) were then combined in equal amounts to form a composition was doped with 25ppm Li, B, Yb, Nb, Zr, Sr, and Hf, 50ppm Sm, and 100ppm Be, Nd, Ce, and Rb. Electron and ion microprobe analyses showed that the olivine crystals and surrounding glasses were homogeneous with respect to major and trace elements. Partition coefficients calculated from these analyses are as follows: 1b: D{sub B} = 4.41 ({+-} 2.3) E-03, D{sub Be} = 2.86 ({+-} 0.45) E-03, D{sub Li} = 1.54 ({+-} 0.21) E-01, 50/50: D{sub B} = 2.86 ({+-} 0.5) E-03, D{sub Be} = 2.07 ({+-} 0.09) E-03, D{sub Li} = 1.51 ({+-} 0.18) E-01, 8c: D{sub B} = 6.05 ({+-} 1.5) E-03, D{sub Be} = 1.81 ({+-} 0.03) E-03, D{sub Li} = 1.31 ({+-} 0.09) E-01. The results of this study will combined with similar data for other minerals as part of a larger study to understand the partitioning behavior of B, Be, and Li in melting of the upper mantle at subduction zones.

  14. Understanding disease processes by partitioned dynamic Bayesian networks.

    PubMed

    Bueno, Marcos L P; Hommersom, Arjen; Lucas, Peter J F; Lappenschaar, Martijn; Janzing, Joost G E

    2016-06-01

    For many clinical problems in patients the underlying pathophysiological process changes in the course of time as a result of medical interventions. In model building for such problems, the typical scarcity of data in a clinical setting has been often compensated by utilizing time homogeneous models, such as dynamic Bayesian networks. As a consequence, the specificities of the underlying process are lost in the obtained models. In the current work, we propose the new concept of partitioned dynamic Bayesian networks to capture distribution regime changes, i.e. time non-homogeneity, benefiting from an intuitive and compact representation with the solid theoretical foundation of Bayesian network models. In order to balance specificity and simplicity in real-world scenarios, we propose a heuristic algorithm to search and learn these non-homogeneous models taking into account a preference for less complex models. An extensive set of experiments were ran, in which simulating experiments show that the heuristic algorithm was capable of constructing well-suited solutions, in terms of goodness of fit and statistical distance to the original distributions, in consonance with the underlying processes that generated data, whether it was homogeneous or non-homogeneous. Finally, a study case on psychotic depression was conducted using non-homogeneous models learned by the heuristic, leading to insightful answers for clinically relevant questions concerning the dynamics of this mental disorder.

  15. Partitioning technique for discrete quantum systems

    SciTech Connect

    Jin, L.; Song, Z.

    2011-06-15

    We develop the partitioning technique for quantum discrete systems. The graph consists of several subgraphs: a central graph and several branch graphs, with each branch graph being rooted by an individual node on the central one. We show that the effective Hamiltonian on the central graph can be constructed by adding additional potentials on the branch-root nodes, which generates the same result as does the the original Hamiltonian on the entire graph. Exactly solvable models are presented to demonstrate the main points of this paper.

  16. Spatially-partitioned many-body vortices

    NASA Astrophysics Data System (ADS)

    Klaiman, S.; Alon, O. E.

    2016-02-01

    A vortex in Bose-Einstein condensates is a localized object which looks much like a tiny tornado storm. It is well described by mean-field theory. In the present work we go beyond the current paradigm and introduce many-body vortices. These are made of spatially- partitioned clouds, carry definite total angular momentum, and are fragmented rather than condensed objects which can only be described beyond mean-field theory. A phase diagram based on a mean-field model assists in predicting the parameters where many-body vortices occur. Implications are briefly discussed.

  17. The minimal length and quantum partition functions

    NASA Astrophysics Data System (ADS)

    Abbasiyan-Motlaq, M.; Pedram, P.

    2014-08-01

    We study the thermodynamics of various physical systems in the framework of the generalized uncertainty principle that implies a minimal length uncertainty proportional to the Planck length. We present a general scheme to analytically calculate the quantum partition function of the physical systems to first order of the deformation parameter based on the behavior of the modified energy spectrum and compare our results with the classical approach. Also, we find the modified internal energy and heat capacity of the systems for the anti-Snyder framework.

  18. Light period regulation of carbohydrate partitioning

    NASA Technical Reports Server (NTRS)

    Janes, Harry W.

    1994-01-01

    We have shown that the photosynthetic period is important in regulating carbon partitioning. Even when the same amount of carbon is fixed over a 24h period considerably more is translocated out of the leaf under the longer photosynthetic period. This is extremely important when parts of the plant other than the leaves are to be sold. It is also important to notice the amount of carbon respired in the short photosynthetic period. The light period effect on carbohydrate fixation, dark respiration, and translocation is shown in this report.

  19. Al Partitioning Patterns and Root Growth as Related to Al Sensitivity and Al Tolerance in Wheat.

    PubMed Central

    Samuels, T. D.; Kucukakyuz, K.; Rincon-Zachary, M.

    1997-01-01

    Studies of Al partitioning and accumulation and of the effect of Al on the growth of intact wheat (Triticum aestivum L.) roots of cultivars that show differential Al sensitivity were conducted. The effects of various Al concentrations on root growth and Al accumulation in the tissue were followed for 24 h. At low external Al concentrations, Al accumulation in the root tips was low and root growth was either unaffected or stimulated. Calculations based on regression analysis of growth and Al accumulation in the root tips predicted that 50% root growth inhibition in the Al-tolerant cv Atlas 66 would be attained when the Al concentrations were 105 [mu]M in the nutrient solution and 376.7 [mu]g Al g-1 dry weight in the tissue. In contrast, in the Al-sensitive cv Tam 105, 50% root growth inhibition would be attained when the Al concentrations were 11 [mu]M in the nutrient solution and 546.2 [mu]g Al g-1 dry weight in the tissue. The data support the hypotheses that differential Al sensitivity correlates with differential Al accumulation in the growing root tissue, and that mechanisms of Al tolerance may be based on strategies to exclude Al from the root meristems. PMID:12223623

  20. Solid consistency

    NASA Astrophysics Data System (ADS)

    Bordin, Lorenzo; Creminelli, Paolo; Mirbabayi, Mehrdad; Noreña, Jorge

    2017-03-01

    We argue that isotropic scalar fluctuations in solid inflation are adiabatic in the super-horizon limit. During the solid phase this adiabatic mode has peculiar features: constant energy-density slices and comoving slices do not coincide, and their curvatures, parameterized respectively by ζ and Script R, both evolve in time. The existence of this adiabatic mode implies that Maldacena's squeezed limit consistency relation holds after angular average over the long mode. The correlation functions of a long-wavelength spherical scalar mode with several short scalar or tensor modes is fixed by the scaling behavior of the correlators of short modes, independently of the solid inflation action or dynamics of reheating.

  1. Bacterial plasmid partition machinery: a minimalist approach to survival.

    PubMed

    Schumacher, Maria A

    2012-02-01

    The accurate segregation or partition of replicated DNA is essential for ensuring stable genome transmission. Partition of bacterial plasmids requires only three elements: a centromere-like DNA site and two proteins, a partition NTPase, and a centromere-binding protein (CBP). Because of this simplicity, partition systems have served as tractable model systems to study the fundamental molecular mechanisms required for DNA segregation at an atomic level. In the last few years, great progress has been made in this endeavor. Surprisingly, these studies have revealed that although the basic partition components are functionally conserved between three types of plasmid partition systems, these systems employ distinct mechanisms of DNA segregation. This review summarizes the molecular insights into plasmid segregation that have been achieved through these recent structural studies.

  2. Partitioning of organophosphorus pesticides into phosphatidylcholine small unilamellar vesicles studied by second-derivative spectrophotometry.

    PubMed

    Takegami, Shigehiko; Kitamura, Keisuke; Ohsugi, Mayuko; Ito, Aya; Kitade, Tatsuya

    2015-06-15

    In order to quantitatively examine the lipophilicity of the widely used organophosphorus pesticides (OPs) chlorfenvinphos (CFVP), chlorpyrifos-methyl (CPFM), diazinon (DZN), fenitrothion (FNT), fenthion (FT), isofenphos (IFP), profenofos (PFF) and pyraclofos (PCF), their partition coefficient (Kp) values between phosphatidylcholine (PC) small unilamellar vesicles (SUVs) and water (liposome-water system) were determined by second-derivative spectrophotometry. The second-derivative spectra of these OPs in the presence of PC SUV showed a bathochromic shift according to the increase in PC concentration and distinct derivative isosbestic points, demonstrating the complete elimination of the residual background signal effects that were observed in the absorption spectra. The Kp values were calculated from the second-derivative intensity change induced by addition of PC SUV and obtained with a good precision of R.S.D. below 10%. The Kp values were in the order of CPFM>FT>PFF>PCF>IFP>CFVP>FNT⩾DZN and did not show a linear correlation relationship with the reported partition coefficients obtained using an n-octanol-water system (R(2)=0.530). Also, the results quantitatively clarified the effect of chemical-group substitution in OPs on their lipophilicity. Since the partition coefficient for the liposome-water system is more effective for modeling the quantitative structure-activity relationship than that for the n-octanol-water system, the obtained results are toxicologically important for estimating the accumulation of these OPs in human cell membranes.

  3. Partitioning of organophosphorus pesticides into phosphatidylcholine small unilamellar vesicles studied by second-derivative spectrophotometry

    NASA Astrophysics Data System (ADS)

    Takegami, Shigehiko; Kitamura, Keisuke; Ohsugi, Mayuko; Ito, Aya; Kitade, Tatsuya

    2015-06-01

    In order to quantitatively examine the lipophilicity of the widely used organophosphorus pesticides (OPs) chlorfenvinphos (CFVP), chlorpyrifos-methyl (CPFM), diazinon (DZN), fenitrothion (FNT), fenthion (FT), isofenphos (IFP), profenofos (PFF) and pyraclofos (PCF), their partition coefficient (Kp) values between phosphatidylcholine (PC) small unilamellar vesicles (SUVs) and water (liposome-water system) were determined by second-derivative spectrophotometry. The second-derivative spectra of these OPs in the presence of PC SUV showed a bathochromic shift according to the increase in PC concentration and distinct derivative isosbestic points, demonstrating the complete elimination of the residual background signal effects that were observed in the absorption spectra. The Kp values were calculated from the second-derivative intensity change induced by addition of PC SUV and obtained with a good precision of R.S.D. below 10%. The Kp values were in the order of CPFM > FT > PFF > PCF > IFP > CFVP > FNT ⩾ DZN and did not show a linear correlation relationship with the reported partition coefficients obtained using an n-octanol-water system (R2 = 0.530). Also, the results quantitatively clarified the effect of chemical-group substitution in OPs on their lipophilicity. Since the partition coefficient for the liposome-water system is more effective for modeling the quantitative structure-activity relationship than that for the n-octanol-water system, the obtained results are toxicologically important for estimating the accumulation of these OPs in human cell membranes.

  4. Alterations in internal partitioning of carbon in soybean plants in response to nitrogen stress

    NASA Technical Reports Server (NTRS)

    Rufty, T. W. Jr; Raper, C. D. Jr; Huber, S. C.

    1984-01-01

    Alterations in internal partitioning of carbon were evaluated in plants exposed to limited nitrogen supply. Vegetative, nonnodulated soybean plants (Glycine max (L.) Merrill, 'Ransom') were grown for 21 days with 1.0 mM NO3- and then exposed to solutions containing 1.0, 0.1, or 0.0 mM NO3- for a 25-day treatment period. In nitrogen-limited plants, there were decreases in emergence of new leaves and in the expansion rate and final area at full expansion of individual leaves. As indicated by alterations in accumulation of dry weight, a larger proportion of available carbon in the plant was partitioned to the roots with decreased availability of nitrogen. Partitioning of reduced nitrogen to the root also was increased and, in plants devoid of an external supply, considerable redistribution of reduced nitrogen from leaves to the root occurred. The general decrease in growth potential and sink strength for nutrients in leaves of nitrogen-limited plants suggested that factors other than simply availability of nitrogen likely were involved in the restriction of growth in the leaf canopy and the associated increase in carbon allocation to the roots.

  5. Role of magnesium in carbon partitioning and alleviating photooxidative damage.

    PubMed

    Cakmak, Ismail; Kirkby, Ernest A

    2008-08-01

    Magnesium (Mg) deficiency exerts a major influence on the partitioning of dry matter and carbohydrates between shoots and roots. One of the very early reactions of plants to Mg deficiency stress is the marked increase in the shoot-to-root dry weight ratio, which is associated with a massive accumulation of carbohydrates in source leaves, especially of sucrose and starch. These higher concentrations of carbohydrates in Mg-deficient leaves together with the accompanying increase in shoot-to-root dry weight ratio are indicative of a severe impairment in phloem export of photoassimilates from source leaves. Studies with common bean and sugar beet plants have shown that Mg plays a fundamental role in phloem loading of sucrose. At a very early stage of Mg deficiency, phloem export of sucrose is severely impaired, an effect that occurs before any noticeable changes in shoot growth, Chl concentration or photosynthetic activity. These findings suggest that accumulation of carbohydrates in Mg-deficient leaves is caused directly by Mg deficiency stress and not as a consequence of reduced sink activity. The role of Mg in the phloem-loading process seems to be specific; resupplying Mg for 12 or 24 h to Mg-deficient plants resulted in a very rapid recovery of sucrose export. It appears that the massive accumulation of carbohydrates and related impairment in photosynthetic CO2 fixation in Mg-deficient leaves cause an over-reduction in the photosynthetic electron transport chain that potentiates the generation of highly reactive O2 species (ROS). Plants respond to Mg deficiency stress by marked increases in antioxidative capacity of leaves, especially under high light intensity, suggesting that ROS generation is stimulated by Mg deficiency in chloroplasts. Accordingly, it has been found that Mg-deficient plants are very susceptible to high light intensity. Exposure of Mg-deficient plants to high light intensity rapidly induced leaf chlorosis and necrosis, an outcome that was

  6. Automatic partitioning of unstructured grids into connected components

    NASA Technical Reports Server (NTRS)

    Dagum, Leonardo

    1993-01-01

    This paper presents two partitioning schemes that guarantee connected components given a connected initial grid. Connected components are important for convergence of methods such as domain decomposition or multigrid. For many of the grids tested, the schemes produce partitions as good (in terms of number of cut edges) or better than spectral partitioning and require only modest computational resources. This paper describes the two schemes in detail and presents comparison results from a number of two and three dimensional unstructured grids.

  7. SORPTION OF ORGANICS ON WASTEWATER SOLIDS: CORRELATION WITH FUNDAMENTAL PROPERTIES.

    EPA Science Inventory

    Sorption of toxic organic compounds on primary, mixed-liquor, and digested solids from municipal wastewater treatment plants has been correlated with octanol/water partition coefficients arid with modified Randic indexes. he correlations developed are useful for assessing the rol...

  8. Apparatus for chemical amplification based on fluid partitioning in an immiscible liquid

    DOEpatents

    Anderson, Brian L [Lodi, CA; Colston, Bill W [San Ramon, CA; Elkin, Christopher J [San Ramon, CA

    2012-05-08

    A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

  9. Method for chemical amplification based on fluid partitioning in an immiscible liquid

    DOEpatents

    Anderson, Brian L.; Colston, Bill W.; Elkin, Christopher J.

    2015-06-02

    A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

  10. Method for chemical amplification based on fluid partitioning in an immiscible liquid

    DOEpatents

    Anderson, Brian L.; Colston, Bill W.; Elkin, Christopher J.

    2017-02-28

    A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

  11. Partitioning kinetic energy during freewheeling wheelchair maneuvers.

    PubMed

    Medola, Fausto O; Dao, Phuc V; Caspall, Jayme J; Sprigle, Stephen

    2014-03-01

    This paper describes a systematic method to partition the kinetic energy (KE) of a free-wheeling wheelchair. An ultralightweight rigid frame wheelchair was instrumented with two axle-mounted encoders and data acquisition equipment to accurately measure the velocity of the drive wheels. A mathematical model was created combining physical specifications and geometry of the wheelchair and its components. Two able-bodied subjects propelled the wheelchair over four courses that involved straight and turning maneuvers at differing speeds. The KE of the wheelchair was divided into three components: translational, rotational, and turning energy. This technique was sensitive to the changing contributions of the three energy components across maneuvers. Translational energy represented the major component of total KE in all maneuvers except a zero radius turn in which turning energy was dominant. Both translational and rotational energies are directly related to wheelchair speed. Partitioning KE offers a useful means of investigating the dynamics of a moving wheelchair. The described technique permits analysis of KE imparted to the wheelchair during maneuvers involving changes in speed and direction, which are most representative of mobility in everyday life. This technique can be used to study the effort required to maneuver different types and configurations of wheelchairs.

  12. Vacuole Partitioning during Meiotic Division in Yeast

    PubMed Central

    Roeder, A. D.; Shaw, J. M.

    1996-01-01

    We have examined the partitioning of the yeast vacuole during meiotic division. In pulse-chase experiments, vacuoles labeled with the lumenal ade2 fluorophore or the membrane-specific dye FM 4-64 were not inherited by haploid spores. Instead, these fluorescent markers were excluded from spores and trapped between the spore cell walls and the ascus. Serial optical sections using a confocal microscope confirmed that spores did not inherit detectable amounts of fluorescently labeled vacuoles. Moreover, indirect immunofluorescence studies established that an endogenous vacuolar membrane protein, alkaline phosphatase, and a soluable vacuolar protease, carboxypeptidase Y, were also detected outside spores after meiotic division. Spores that did not inherit ade2- or FM 4-64-labeled vacuoles did generate an organelle that could be visualized by subsequent staining with vacuole-specific fluorophores. These data contrast with genetic evidence that a soluble vacuolar protease is inherited by spores. When the partitioning of both types of markers was examined in sporulating cultures, the vacuolar protease activity was inherited by spores while fluorescently labeled vacuoles were largely excluded from spores. Our results indicate that the majority of the diploid vacuole, both soluble contents and membrane-bound components, are excluded from spores formed during meiotic division. PMID:8889511

  13. Partitioning in parallel processing of production systems

    SciTech Connect

    Oflazer, K.

    1987-01-01

    This thesis presents research on certain issues related to parallel processing of production systems. It first presents a parallel production system interpreter that has been implemented on a four-processor multiprocessor. This parallel interpreter is based on Forgy's OPS5 interpreter and exploits production-level parallelism in production systems. Runs on the multiprocessor system indicate that it is possible to obtain speed-up of around 1.7 in the match computation for certain production systems when productions are split into three sets that are processed in parallel. The next issue addressed is that of partitioning a set of rules to processors in a parallel interpreter with production-level parallelism, and the extent of additional improvement in performance. The partitioning problem is formulated and an algorithm for approximate solutions is presented. The thesis next presents a parallel processing scheme for OPS5 production systems that allows some redundancy in the match computation. This redundancy enables the processing of a production to be divided into units of medium granularity each of which can be processed in parallel. Subsequently, a parallel processor architecture for implementing the parallel processing algorithm is presented.

  14. New parallel SOR method by domain partitioning

    SciTech Connect

    Xie, Dexuan

    1996-12-31

    In this paper, we propose and analyze a new parallel SOR method, the PSOR method, formulated by using domain partitioning together with an interprocessor data-communication technique. For the 5-point approximation to the Poisson equation on a square, we show that the ordering of the PSOR based on the strip partition leads to a consistently ordered matrix, and hence the PSOR and the SOR using the row-wise ordering have the same convergence rate. However, in general, the ordering used in PSOR may not be {open_quote}consistently ordered{close_quotes}. So, there is a need to analyze the convergence of PSOR directly. In this paper, we present a PSOR theory, and show that the PSOR method can have the same asymptotic rate of convergence as the corresponding sequential SOR method for a wide class of linear systems in which the matrix is {open_quotes}consistently ordered{close_quotes}. Finally, we demonstrate the parallel performance of the PSOR method on four different message passing multiprocessors (a KSR1, the Intel Delta, an Intel Paragon and an IBM SP2), along with a comparison with the point Red-Black and four-color SOR methods.

  15. Ferrous iron partitioning in the lower mantle

    NASA Astrophysics Data System (ADS)

    Muir, Joshua M. R.; Brodholt, John P.

    2016-08-01

    We used density functional theory (DFT) to examine the partitioning of ferrous iron between periclase and bridgmanite under lower mantle conditions. To study the effects of the three major variables - pressure, temperature and concentration - these have been varied from 0 to 150 GPa, from 1000 to 4000 K and from 0 to 100% total iron content. We find that increasing temperature increases KD, increasing iron concentration decreases KD, while pressure can both increase and decrease KD. We find that KD decreases slowly from about 0.32 to 0.06 with depth under lower mantle conditions. We also find that KD increases sharply to 0.15 in the very lowermost mantle due to the strong temperature increases near the CMB. Spin transitions have a large effect on the activity of ferropericlase which causes KD to vary with pressure in a peak-like fashion. Despite the apparently large changes in KD through the mantle, this actually results in relatively small changes in total iron content in the two phases, with XFefp ranging from about 0.20 to 0.35, before decreasing again to about 0.28 at the CMB, and XFebd has a pretty constant value of about 0.04-0.07 throughout the lower mantle. For the very high Fe concentrations suggested for ULVZs, Fe partitions very strongly into ferropericlase.

  16. Recursive partitioning for heterogeneous causal effects.

    PubMed

    Athey, Susan; Imbens, Guido

    2016-07-05

    In this paper we propose methods for estimating heterogeneity in causal effects in experimental and observational studies and for conducting hypothesis tests about the magnitude of differences in treatment effects across subsets of the population. We provide a data-driven approach to partition the data into subpopulations that differ in the magnitude of their treatment effects. The approach enables the construction of valid confidence intervals for treatment effects, even with many covariates relative to the sample size, and without "sparsity" assumptions. We propose an "honest" approach to estimation, whereby one sample is used to construct the partition and another to estimate treatment effects for each subpopulation. Our approach builds on regression tree methods, modified to optimize for goodness of fit in treatment effects and to account for honest estimation. Our model selection criterion anticipates that bias will be eliminated by honest estimation and also accounts for the effect of making additional splits on the variance of treatment effect estimates within each subpopulation. We address the challenge that the "ground truth" for a causal effect is not observed for any individual unit, so that standard approaches to cross-validation must be modified. Through a simulation study, we show that for our preferred method honest estimation results in nominal coverage for 90% confidence intervals, whereas coverage ranges between 74% and 84% for nonhonest approaches. Honest estimation requires estimating the model with a smaller sample size; the cost in terms of mean squared error of treatment effects for our preferred method ranges between 7-22%.

  17. Gait Partitioning Methods: A Systematic Review

    PubMed Central

    Taborri, Juri; Palermo, Eduardo; Rossi, Stefano; Cappa, Paolo

    2016-01-01

    In the last years, gait phase partitioning has come to be a challenging research topic due to its impact on several applications related to gait technologies. A variety of sensors can be used to feed algorithms for gait phase partitioning, mainly classifiable as wearable or non-wearable. Among wearable sensors, footswitches or foot pressure insoles are generally considered as the gold standard; however, to overcome some inherent limitations of the former, inertial measurement units have become popular in recent decades. Valuable results have been achieved also though electromyography, electroneurography, and ultrasonic sensors. Non-wearable sensors, such as opto-electronic systems along with force platforms, remain the most accurate system to perform gait analysis in an indoor environment. In the present paper we identify, select, and categorize the available methodologies for gait phase detection, analyzing advantages and disadvantages of each solution. Finally, we comparatively examine the obtainable gait phase granularities, the usable computational methodologies and the optimal sensor placements on the targeted body segments. PMID:26751449

  18. Natural Microbial Assemblages Reflect Distinct Organismal and Functional Partitioning

    NASA Astrophysics Data System (ADS)

    Wilmes, P.; Andersson, A.; Kalnejais, L. H.; Verberkmoes, N. C.; Lefsrud, M. G.; Wexler, M.; Singer, S. W.; Shah, M.; Bond, P. L.; Thelen, M. P.; Hettich, R. L.; Banfield, J. F.

    2007-12-01

    The ability to link microbial community structure to function has long been a primary focus of environmental microbiology. With the advent of community genomic and proteomic techniques, along with advances in microscopic imaging techniques, it is now possible to gain insights into the organismal and functional makeup of microbial communities. Biofilms growing within highly acidic solutions inside the Richmond Mine (Iron Mountain, Redding, California) exhibit distinct macro- and microscopic morphologies. They are composed of microorganisms belonging to the three domains of life, including archaea, bacteria and eukarya. The proportion of each organismal type depends on sampling location and developmental stage. For example, mature biofilms floating on top of acid mine drainage (AMD) pools exhibit layers consisting of a densely packed bottom layer of the chemoautolithotroph Leptospirillum group II, a less dense top layer composed mainly of archaea, and fungal filaments spanning across the entire biofilm. The expression of cytochrome 579 (the most highly abundant protein in the biofilm, believed to be central to iron oxidation and encoded by Leptospirillum group II) is localized at the interface of the biofilm with the AMD solution, highlighting that biofilm architecture is reflected at the functional gene expression level. Distinct functional partitioning is also apparent in a biological wastewater treatment system that selects for distinct polyphosphate accumulating organisms. Community genomic data from " Candidatus Accumulibacter phosphatis" dominated activated sludge has enabled high mass-accuracy shotgun proteomics for identification of key metabolic pathways. Comprehensive genome-wide alignment of orthologous proteins suggests distinct partitioning of protein variants involved in both core-metabolism and specific metabolic pathways among the dominant population and closely related species. In addition, strain- resolved proteogenomic analysis of the AMD biofilms

  19. A partitioning strategy for nonuniform problems on multiprocessors

    NASA Technical Reports Server (NTRS)

    Berger, M. J.; Bokhari, S.

    1985-01-01

    The partitioning of a problem on a domain with unequal work estimates in different subddomains is considered in a way that balances the work load across multiple processors. Such a problem arises for example in solving partial differential equations using an adaptive method that places extra grid points in certain subregions of the domain. A binary decomposition of the domain is used to partition it into rectangles requiring equal computational effort. The communication costs of mapping this partitioning onto different microprocessors: a mesh-connected array, a tree machine and a hypercube is then studied. The communication cost expressions can be used to determine the optimal depth of the above partitioning.

  20. Partition of nonionic organic compounds in aquatic systems

    USGS Publications Warehouse

    Smith, James A.; Witkowski, Patrick J.; Chiou, Cary T.

    1988-01-01

    In aqueous systems, the distribution of many nonionic organic solutes in soil-sediment, aquatic organisms, and dissolved organic matter can be explained in terms of a partition model. The nonionic organic solute is distributed between water and different organic phases that behave as bulk solvents. Factors such as polarity, composition, and molecular size of the solute and organic phase determine the relative importance of partition to the environmental distribution of the solute. This chapter reviews these factors in the context of a partition model and also examines several environmental applications of the partition model for surface- and ground-water systems.

  1. Deep eutectic solvents in countercurrent and centrifugal partition chromatography.

    PubMed

    Roehrer, Simon; Bezold, Franziska; García, Eva Marra; Minceva, Mirjana

    2016-02-19

    Deep eutectic solvents (DESs) were evaluated as solvents in centrifugal partition chromatography, a liquid-liquid chromatography separation technology. To this end, the partition coefficients of ten natural compounds of different hydrophobicity were determined in non-aqueous biphasic systems containing DES. The influence of the composition of DESs and the presence of water in the biphasic system on the partition coefficient were also examined. In addition, several process relevant physical properties of the biphasic system, such as the density and viscosity of the phases, were measured. A mixture of three to four hydrophobic compounds was successfully separated in a centrifugal partition extractor using a heptane/ethanol/DES biphasic system.

  2. Chaos synchronization basing on symbolic dynamics with nongenerating partition.

    PubMed

    Wang, Xingyuan; Wang, Mogei; Liu, Zhenzhen

    2009-06-01

    Using symbolic dynamics and information theory, we study the information transmission needed for synchronizing unidirectionally coupled oscillators. It is found that when sustaining chaos synchronization with nongenerating partition, the synchronization error will be larger than a critical value, although the required coupled channel capacity can be smaller than the case of using a generating partition. Then we show that no matter whether a generating or nongenerating partition is in use, a high-quality detector can guarantee the lead of the response oscillator, while the lag responding can make up the low precision of the detector. A practicable synchronization scheme basing on a nongenerating partition is also proposed in this paper.

  3. Biochemical aspects of lipid accumulation in silicon deficient cyclotella cryptica

    SciTech Connect

    Roessler, P.G. )

    1987-06-01

    The experiments described in this report were designed to elucidate the biochemical mechanisms responsible for lipid accumulation in silicon-deficient Cyclotella cryptica T13L cells. Studies using NaH{sup 14}CO{sub 3} as a tracer indicated that the fraction of newly assimilated carbon partitioned into lipids doubled after 4 h of Si deficiency, while the fraction partitioned into chrysolaminarin decreased by 51%. Pulse-chase experiments indicated that a slow redistribution of previously assimilated carbon into lipids also occurred. Several enzymes were assayed in cell-free extracts made from Si-replete and Si-deficient cells. Si deficiency did not affect the specific activity of UDP glucose pyrophosphorylase, the first enzyme of the chrysolaminarin synthesis pathway, but led to a 31% reduction in the activity of chrysolaminarin synthase (UDP glucose: {beta}-1, 3-glucan {beta}-3-glucosyl transferase). The activity of acetyl-CoA carboxylase (the first committed step in lipid biosynthesis) increased by 87% in response to Si deficiency, suggesting either covalent activation or increased levels of this enzyme. The activities of citrate synthase and acetyl-CoA synthetase were not affected by Si deficiency. These results suggest that lipid accumulation in Si deficient cells may be due in part to changes in the activities of chrysolaminarin synthase and acetyl-CoA carboxylase.

  4. Partition coefficient of cadmium between organic soils and bean and oat plants

    SciTech Connect

    Siddqui, M.F.R.; Courchesne, F.; Kennedy, G.; Zayed, J.

    1995-12-31

    Environmental fate models require the partition coefficient data of contaminants among two or more environmental compartments. The bioaccumulation of cadmium (Cd) by bean and oat plants grown on organic soils in a controlled growth chamber was investigated to validate the plant/soil partition coefficient. Total Cd was measured in the soils and in the different parts of the plants. The mean total Cd concentrations for soil cultivated with beans and oats were 0.86 and 0.69 {micro}g/g, respectively. Selective extractants (BaCl{sub 2}, Na-pyrophosphate and HNO{sub 3}-hydroxy) were used to evaluate solid phase Cd species in the soil. In the soil cultivated with bean, BaCl{sub 2} exchangeable, Na-pyrophosphate extractable and HNO{sub 3}-NH{sub 2}OH extractable Cd represented 1.2, 1.6 and 50.9% of total soil Cd, respectively. For the soil cultivated with oats, the same extractants gave values of 1.1, 1.8 and 61.9%. Cd concentration levels in bean plants followed the sequence roots > fruits = stems > leaves (p < 0.01) while the following sequence was observed for oat plants: roots > fruits > stems > leaves (p < 0.05). The partition coefficient for total Cd (Cd{sub Plant tissue}/Cd{sub Soil}) was in the range of 0.28--0.55 for bean plants and 1.03--1.86 for oat plants.

  5. Fabrication of liquid-filled square lens array with hemispherical partition walls

    NASA Astrophysics Data System (ADS)

    Koo, Gyohyun; Kim, Junoh; Kim, Cheoljoong; Shin, Dooseub; Lee, Junsik; Won, Yong Hyub

    2016-03-01

    Liquid-filled square lens array has been developed for an alternative to solid lens array because of its advantage in variable focus length. In addition, the square lens array has advantage with high fill factor compared to liquid circular lens array which is another alternative. However, one of the main limitations of conventional square lens array is the distortion. In this paper, distortion-free liquid square lens array is proposed. The partition walls of the proposed square lens array is fabricated into hemispherical shape to reduce the distortion, and then additional vertical walls are set up on the hemispherical structures to unify the height of partition walls and divide chamber sections. UV lithography techniques are used to fabricate this structure, and diffuser which has an angle of 80 degrees is used in the process. Photoresist is exposed to scattered ultraviolet rays which pass through the diffuser, and hemispherical lens-shaped structures of photoresist remains after development process. Supplementary vertical partition walls are obtained by additional photoresist patterning process on the structure. In this structure, the interface between oil and water comes into contact with the surface of the hemispherical walls, and the refractive index of oil and the walls are equally matched to maximize the part which acts as lens in the chamber. The proposed liquid square lens array can provide us with aberration-free 3D images with high fill factor.

  6. Parallel Processing of Big Point Clouds Using Z-Order Partitioning

    NASA Astrophysics Data System (ADS)

    Alis, C.; Boehm, J.; Liu, K.

    2016-06-01

    As laser scanning technology improves and costs are coming down, the amount of point cloud data being generated can be prohibitively difficult and expensive to process on a single machine. This data explosion is not only limited to point cloud data. Voluminous amounts of high-dimensionality and quickly accumulating data, collectively known as Big Data, such as those generated by social media, Internet of Things devices and commercial transactions, are becoming more prevalent as well. New computing paradigms and frameworks are being developed to efficiently handle the processing of Big Data, many of which utilize a compute cluster composed of several commodity grade machines to process chunks of data in parallel. A central concept in many of these frameworks is data locality. By its nature, Big Data is large enough that the entire dataset would not fit on the memory and hard drives of a single node hence replicating the entire dataset to each worker node is impractical. The data must then be partitioned across worker nodes in a manner that minimises data transfer across the network. This is a challenge for point cloud data because there exist different ways to partition data and they may require data transfer. We propose a partitioning based on Z-order which is a form of locality-sensitive hashing. The Z-order or Morton code is computed by dividing each dimension to form a grid then interleaving the binary representation of each dimension. For example, the Z-order code for the grid square with coordinates (x = 1 = 012, y = 3 = 112) is 10112 = 11. The number of points in each partition is controlled by the number of bits per dimension: the more bits, the fewer the points. The number of bits per dimension also controls the level of detail with more bits yielding finer partitioning. We present this partitioning method by implementing it on Apache Spark and investigating how different parameters affect the accuracy and running time of the k nearest neighbour algorithm

  7. Structural determinants of drug partitioning in n-hexadecane/water system.

    PubMed

    Natesan, Senthil; Wang, Zhanbin; Lukacova, Viera; Peng, Ming; Subramaniam, Rajesh; Lynch, Sandra; Balaz, Stefan

    2013-06-24

    Surrogate phases have been widely used as correlates for modeling transport and partitioning of drugs in biological systems, taking advantage of chemical similarity between the surrogate and the phospholipid bilayer as the elementary unit of biological phases, which is responsible for most of the transport and partitioning. Solvation in strata of the phospholipid bilayer is an important drug characteristic because it affects the rates of absorption and distribution, as well as the interactions with the membrane proteins having the binding sites located inside the bilayer. The bilayer core can be emulated by n-hexadecane (C16), and the headgroup stratum is often considered a hydrophilic phase because of the high water content. Therefore, we tested the hypothesis that the C16/water partition coefficients (P) can predict the bilayer locations of drugs and other small molecules better than other surrogate systems. Altogether 514 PC16/W values for nonionizable (458) and completely ionized (56) compounds were collected from the literature or measured, when necessary. With the intent to create a fragment-based prediction system, the PC16/W values were factorized into the fragment solvation parameters (f) and correction factors based on the ClogP fragmentation scheme. A script for the PC16/W prediction using the ClogP output is provided. To further expand the prediction system and reveal solvation differences, the fC16/W values were correlated with their more widely available counterparts for the 1-octanol/water system (O/W) using solvatochromic parameters. The analysis for 50 compounds with known bilayer location shows that the available and predicted PC16/W and PO/W values alone or the PC16/O values representing their ratio do not satisfactorily predict the preference for drug accumulation in bilayer strata. These observations indicate that the headgroups stratum, albeit well hydrated, does not have solvation characteristics similar to water and is also poorly described

  8. Effects of sulfur on lead partitioning during sludge incineration based on experiments and thermodynamic calculations

    SciTech Connect

    Liu, Jing-yong; Huang, Shu-jie; Sun, Shui-yu; Ning, Xun-an; He, Rui-zhe; Li, Xiao-ming; Chen, Tao; Luo, Guang-qian; Xie, Wu-ming; Wang, Yu-jie; Zhuo, Zhong-xu; Fu, Jie-wen

    2015-04-15

    Highlights: • A thermodynamic equilibrium calculation was carried out. • Effects of three types of sulfurs on Pb distribution were investigated. • The mechanism for three types of sulfurs acting on Pb partitioning were proposed. • Lead partitioning and species in bottom ash and fly ash were identified. - Abstract: Experiments in a tubular furnace reactor and thermodynamic equilibrium calculations were conducted to investigate the impact of sulfur compounds on the migration of lead (Pb) during sludge incineration. Representative samples of typical sludge with and without the addition of sulfur compounds were combusted at 850 °C, and the partitioning of Pb in the solid phase (bottom ash) and gas phase (fly ash and flue gas) was quantified. The results indicate that three types of sulfur compounds (S, Na{sub 2}S and Na{sub 2}SO{sub 4}) added to the sludge could facilitate the volatilization of Pb in the gas phase (fly ash and flue gas) into metal sulfates displacing its sulfides and some of its oxides. The effect of promoting Pb volatilization by adding Na{sub 2}SO{sub 4} and Na{sub 2}S was superior to that of the addition of S. In bottom ash, different metallic sulfides were found in the forms of lead sulfide, aluminosilicate minerals, and polymetallic-sulfides, which were minimally volatilized. The chemical equilibrium calculations indicated that sulfur stabilizes Pb in the form of PbSO{sub 4}(s) at low temperatures (<1000 K). The equilibrium calculation prediction also suggested that SiO{sub 2}, CaO, TiO{sub 2}, and Al{sub 2}O{sub 3} containing materials function as condensed phase solids in the temperature range of 800–1100 K as sorbents to stabilize Pb. However, in the presence of sulfur or chlorine or the co-existence of sulfur and chlorine, these sorbents were inactive. The effect of sulfur on Pb partitioning in the sludge incineration process mainly depended on the gas phase reaction, the surface reaction, the volatilization of products, and the

  9. Accumulation of Chiro-inositol and Other Non-structural Carbohydrates in Limonium Species in Response to Saline Irrigation Waters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two statice cultivars, Limonium perezii (Stapf) F. T. Hubb cv. ‘Blue Seas’ and L. sinuatum (L.) Mill ‘American Beauty’, were grown in greenhouse sand tanks to determine the effect of salt stress on carbohydrate accumulation and partitioning. Irrigation waters were prepared to simulate typical saline...

  10. Effect of elevated CO2 on carbon partitioning in young Quercus ilex L. during resprouting.

    PubMed

    Aranjuelo, Iker; Pintó-Marijuan, Marta; Avice, Jean Christophe; Fleck, Isabel

    2011-06-15

    Stored carbon (C) represents a very important C pool with residence times of years to decades in tree organic matter. With the objective of understanding C assimilation, partitioning and remobilization in 2-year-old Quercus ilex L., those trees were exposed for 7 months to different [CO(2)] (elevated: 700  µmol mol(-1) ; and ambient: 350 µmol mol(-1) CO(2)). The (13)C-isotopic composition of the ambient CO(2) (ca.-12.8‰) was modified (to ca.-19.2‰) under the elevated CO(2) conditions in order to analyze C allocation and partitioning before aerial biomass excision, and during the following regrowth (resprouting). Although after 7 months of growth under elevated [CO(2)], Q. ilex plants increased dry matter production, the absence of significant differences in photosynthetic activity suggests that such an increase was lower than expected. Nitrogen availability was not involved in photosynthetic acclimation. The removal of aboveground organs did not enable the balance between C availability and C requirements to be achieved. The isotopic characterization revealed that before the cutting, C partitioning to the stem (main C sink) prevented leaf C accumulation. During regrowth the roots were the organ with more of the labelled C. Furthermore, developing leaves had more C sink strength than shoots during this period. After the cutting, the amount of C delivered from the root to the development of aboveground organs exceeded the requirements of leaves, with the consequent carbohydrate accumulation. These findings demonstrate that, despite having a new C sink, the responsiveness of those resprouts under elevated [CO(2)] conditions will be strongly conditioned by the plant's capacity to use the extra C present in leaves through its allocation to other organs (roots) and processes (respiration).

  11. Interspecific resource partitioning in sympatric ursids

    USGS Publications Warehouse

    Belant, J.L.; Kielland, K.; Follmann, E.H.; Adams, L.G.

    2006-01-01

    The fundamental niche of a species is rarely if ever realized because the presence of other species restricts it to a narrower range of ecological conditions. The effects of this narrower range of conditions define how resources are partitioned. Resource partitioning has been inferred but not demonstrated previously for sympatric ursids. We estimated assimilated diet in relation to body condition (body fat and lean and total body mass) and reproduction for sympatric brown bears (Ursus arctos) and American black bears (U. americanus) in southcentral Alaska, 1998-2000. Based on isotopic analysis of blood and keratin in claws, salmon (Oncorhynchus spp.) predominated in brown bear diets (>53% annually) whereas black bears assimilated 0-25% salmon annually. Black bears did not exploit salmon during a year with below average spawning numbers, probably because brown bears deterred black bear access to salmon. Proportion of salmon in assimilated diet was consistent across years for brown bears and represented the major portion of their diet. Body size of brown bears in the study area approached mean body size of several coastal brown bear populations, demonstrating the importance of salmon availability to body condition. Black bears occurred at a comparable density (mass:mass), but body condition varied and was related directly to the amount of salmon assimilated in their diet. Both species gained most lean body mass during spring and all body fat during summer when salmon were present. Improved body condition (i.e., increased percentage body fat) from salmon consumption reduced catabolism of lean body mass during hibernation, resulting in better body condition the following spring. Further, black bear reproduction was directly related to body condition; reproductive rates were reduced when body condition was lower. High body fat content across years for brown bears was reflected in consistently high reproductive levels. We suggest that the fundamental niche of black bears

  12. Transgenic approaches to altering carbon and nitrogen partitioning in whole plants: assessing the potential to improve crop yields and nutritional quality

    SciTech Connect

    Yadav, Umesh P.; Ayre, Brian G.; Bush, Daniel R.

    2015-04-22

    The principal components of plant productivity and nutritional value, from the standpoint of modern agriculture, are the acquisition and partitioning of organic carbon (C) and nitrogen (N) compounds among the various organs of the plant. The flow of essential organic nutrients among the plant organ systems is mediated by its complex vascular system, and is driven by a series of transport steps including export from sites of primary assimilation, transport into and out of the phloem and xylem, and transport into the various import-dependent organs. Manipulating C and N partitioning to enhance yield of harvested organs is evident in the earliest crop domestication events and continues to be a goal for modern plant biology. Research on the biochemistry, molecular and cellular biology, and physiology of C and N partitioning has now matured to an extent that strategic manipulation of these transport systems through biotechnology are being attempted to improve movement from source to sink tissues in general, but also to target partitioning to specific organs. These nascent efforts are demonstrating the potential of applied biomass targeting but are also identifying interactions between essential nutrients that require further basic research. In this review, we summarize the key transport steps involved in C and N partitioning, and discuss various transgenic approaches for directly manipulating key C and N transporters involved. In addition, we propose several experiments that could enhance biomass accumulation in targeted organs while simultaneously testing current partitioning models.

  13. Transgenic approaches to altering carbon and nitrogen partitioning in whole plants: assessing the potential to improve crop yields and nutritional quality

    DOE PAGES

    Yadav, Umesh P.; Ayre, Brian G.; Bush, Daniel R.

    2015-04-22

    The principal components of plant productivity and nutritional value, from the standpoint of modern agriculture, are the acquisition and partitioning of organic carbon (C) and nitrogen (N) compounds among the various organs of the plant. The flow of essential organic nutrients among the plant organ systems is mediated by its complex vascular system, and is driven by a series of transport steps including export from sites of primary assimilation, transport into and out of the phloem and xylem, and transport into the various import-dependent organs. Manipulating C and N partitioning to enhance yield of harvested organs is evident in themore » earliest crop domestication events and continues to be a goal for modern plant biology. Research on the biochemistry, molecular and cellular biology, and physiology of C and N partitioning has now matured to an extent that strategic manipulation of these transport systems through biotechnology are being attempted to improve movement from source to sink tissues in general, but also to target partitioning to specific organs. These nascent efforts are demonstrating the potential of applied biomass targeting but are also identifying interactions between essential nutrients that require further basic research. In this review, we summarize the key transport steps involved in C and N partitioning, and discuss various transgenic approaches for directly manipulating key C and N transporters involved. In addition, we propose several experiments that could enhance biomass accumulation in targeted organs while simultaneously testing current partitioning models.« less

  14. Transgenic approaches to altering carbon and nitrogen partitioning in whole plants: assessing the potential to improve crop yields and nutritional quality

    PubMed Central

    Yadav, Umesh P.; Ayre, Brian G.; Bush, Daniel R.

    2015-01-01

    The principal components of plant productivity and nutritional value, from the standpoint of modern agriculture, are the acquisition and partitioning of organic carbon (C) and nitrogen (N) compounds among the various organs of the plant. The flow of essential organic nutrients among the plant organ systems is mediated by its complex vascular system, and is driven by a series of transport steps including export from sites of primary assimilation, transport into and out of the phloem and xylem, and transport into the various import-dependent organs. Manipulating C and N partitioning to enhance yield of harvested organs is evident in the earliest crop domestication events and continues to be a goal for modern plant biology. Research on the biochemistry, molecular and cellular biology, and physiology of C and N partitioning has now matured to an extent that strategic manipulation of these transport systems through biotechnology are being attempted to improve movement from source to sink tissues in general, but also to target partitioning to specific organs. These nascent efforts are demonstrating the potential of applied biomass targeting but are also identifying interactions between essential nutrients that require further basic research. In this review, we summarize the key transport steps involved in C and N partitioning, and discuss various transgenic approaches for directly manipulating key C and N transporters involved. In addition, we propose several experiments that could enhance biomass accumulation in targeted organs while simultaneously testing current partitioning models. PMID:25954297

  15. Hydrogen partitioning in pure cast aluminum as determined by dynamic evolution rate measurements

    NASA Technical Reports Server (NTRS)

    Outlaw, R. A.; Peterson, D. T.; Schmidt, F. A.

    1981-01-01

    Hydrogen in pure aluminum can be found in two different states. One is related to a presence in gas-filled pores, while the other state involves the formation of a solid solution between hydrogen and aluminum. The considered investigation is concerned with the distribution of the hydrogen between various states. A dynamic technique is employed to measure the evolution of hydrogen from commercially available samples of polycrystalline pure aluminum under ultrahigh vacuum conditions. The obtained data are compared with the results of a statistical analysis concerning the porosity in the cast aluminum. It was found that more than 99 pct of the hydrogen in the aluminum is located in large pores. Less than 1 pct of the hydrogen is partitioned between the solid solution and the small pores.

  16. Evaluation of Partitioning Gas Tracer Tests for Measuring Water in Landfills

    NASA Astrophysics Data System (ADS)

    Imhoff, P. T.; Han, B.; Jafarpour, Y.; Gallagher, V. N.; Chiu, P. C.; Fluman, D. A.; Vasuki, N. C.; Yazdani, R.; Augenstein, D.; Cohen, K. K.

    2003-12-01

    Methane is an important greenhouse gas, and landfills are the largest anthropogenic source in many developed countries. Bioreactor landfills have been proposed as one means of abating greenhouse gas emissions from landfills. Here, the decomposition of organic wastes is enhanced by the controlled addition of water or leachate to maintain optimal conditions for waste decomposition. Greenhouse gas abatement is accomplished by sequestration of photosynthetically derived carbon in wastes, CO2 offsets from energy use of waste derived gas, and mitigation of methane emission from the wastes. An important issue in the operation of bioreactor landfills is knowing how much water to add and where to add it. Accurate methods for measuring the amount of water in landfills would be valuable aids for implementing leachate recirculation systems. Current methods for measuring water are inadequate, though, since they provide point measurements and are frequently affected by heterogeneity of the solid waste composition and solid waste compaction. The value of point measurements is significantly reduced in systems where water flows preferentially, such as in landfills. Here, spatially integrated measurements might be of greater value. We are evaluating a promising technology, the partitioning gas tracer test, to measure the water saturation within landfills, the amount of free water in solid waste divided by the volume of the voids. The partitioning gas tracer test was recently developed by researchers working in the vadose zone. We report the results from laboratory and field tests designed to evaluate the partitioning gas tracer test within an anaerobic landfill operated by the Delaware Solid Waste Authority. Vertical wells were installed within the landfill to inject and extract tracer gases. Gas flow and tracer gas movement in the solid waste were controlled by the landfill's existing gas collection system, which included vertical wells installed throughout the landfill through

  17. Solid Solutions

    NASA Astrophysics Data System (ADS)

    Lee, Go-Eun; Kim, Il-Ho; Lim, Young Soo; Seo, Won-Seon; Choi, Byeong-Jun; Hwang, Chang-Won

    2014-06-01

    Since Bi2Te3 and Bi2Se3 have the same crystal structure, they form a homogeneous solid solution. Therefore, the thermal conductivity of the solid solution can be reduced by phonon scattering. The thermoelectric figure of merit can be improved by controlling the carrier concentration through doping. In this study, Bi2Te2.85Se0.15:D m (D: dopants such as I, Cu, Ag, Ni, Zn) solid solutions were prepared by encapsulated melting and hot pressing. All specimens exhibited n-type conduction in the measured temperature range (323 K to 523 K), and their electrical conductivities decreased slightly with increasing temperature. The undoped solid solution showed a carrier concentration of 7.37 × 1019 cm-3, power factor of 2.1 mW m-1 K-1, and figure of merit of 0.56 at 323 K. The figure of merit ( ZT) was improved due to the increased power factor by I, Cu, and Ag dopings, and maximum ZT values were obtained as 0.76 at 323 K for Bi2Te2.85Se0.15:Cu0.01 and 0.90 at 423 K for Bi2Te2.85Se0.15:I0.005. However, the thermoelectric properties of Ni- and Zn-doped solid solutions were not enhanced.

  18. Advanced Aqueous Separation Systems for Actinide Partitioning

    SciTech Connect

    Nash, Kenneth L.; Clark, Sue; Meier, G Patrick; Alexandratos, Spiro; Paine, Robert; Hancock, Robert; Ensor, Dale

    2012-03-21

    One of the most challenging aspects of advanced processing of spent nuclear fuel is the need to isolate transuranium elements from fission product lanthanides. This project expanded the scope of earlier investigations of americium (Am) partitioning from the lanthanides with the synthesis of new separations materials and a centralized focus on radiochemical characterization of the separation systems that could be developed based on these new materials. The primary objective of this program was to explore alternative materials for actinide separations and to link the design of new reagents for actinide separations to characterizations based on actinide chemistry. In the predominant trivalent oxidation state, the chemistry of lanthanides overlaps substantially with that of the trivalent actinides and their mutual separation is quite challenging.

  19. Experimental investigation of the iodine partition coefficient

    SciTech Connect

    Kelly, J.L.; Babad, C.J.; Mulder, R.U.

    1985-11-01

    Short-term values of the iodine partition coefficient (IPC) were evaluated experimentally by an air/water system over the following ranges of conditions: temperature = 25 to 70/sup 0/C, pH = 5 to 9, and iodine concentration = 10/sup -9/ to 10/sup -2/ kg iodine/m/sup 3/ H/sub 2/O. The experimental IPC values are relatively independent of temperature over the indicated range, but show a significant dependence on pH and iodine concentration. In basic solutions the short-term values are several orders of magnitude less than the true equilibrium values; in acid solutions, the differences are much less. These results are useful for predicting the disposition of iodine shortly (i.e., 1 to 10 h) after iodine has been released into an air/water environment.

  20. Partitional Classification: A Complement to Phylogeny

    PubMed Central

    Salomon, Marc; Dassy, Bruno

    2016-01-01

    The tree of life is currently an active object of research, though next to vertical gene transmission non vertical gene transfers proved to play a significant role in the evolutionary process. To overcome this difficulty, trees of life are now constructed from genes hypothesized vital, on the assumption that these are all transmitted vertically. This view has been challenged. As a frame for this discussion, we developed a partitional taxonomical system clustering taxa at a high taxonomical rank. Our analysis (1) selects RNase P RNA sequences of bacterial, archaeal, and eucaryal genera from genetic databases, (2) submits the sequences, aligned, to k-medoid analysis to obtain clusters, (3) establishes the correspondence between clusters and taxa, (4) constructs from the taxa a new type of taxon, the genetic community (GC), and (5) classifies the GCs: Archaea–Eukaryotes contrastingly different from the six others, all bacterial. The GCs would be the broadest frame to carry out the phylogenies. PMID:27346943

  1. Exometabolite niche partitioning among sympatric soil bacteria

    PubMed Central

    Baran, Richard; Brodie, Eoin L.; Mayberry-Lewis, Jazmine; Hummel, Eric; Da Rocha, Ulisses Nunes; Chakraborty, Romy; Bowen, Benjamin P.; Karaoz, Ulas; Cadillo-Quiroz, Hinsby; Garcia-Pichel, Ferran; Northen, Trent R.

    2015-01-01

    Soils are arguably the most microbially diverse ecosystems. Physicochemical properties have been associated with the maintenance of this diversity. Yet, the role of microbial substrate specialization is largely unexplored since substrate utilization studies have focused on simple substrates, not the complex mixtures representative of the soil environment. Here we examine the exometabolite composition of desert biological soil crusts (biocrusts) and the substrate preferences of seven biocrust isolates. The biocrust's main primary producer releases a diverse array of metabolites, and isolates of physically associated taxa use unique subsets of the complex metabolite pool. Individual isolates use only 13−26% of available metabolites, with only 2 out of 470 used by all and 40% not used by any. An extension of this approach to a mesophilic soil environment also reveals high levels of microbial substrate specialization. These results suggest that exometabolite niche partitioning may be an important factor in the maintenance of microbial diversity. PMID:26392107

  2. Exometabolite niche partitioning among sympatric soil bacteria

    SciTech Connect

    Baran, Richard; Brodie, Eoin L.; Mayberry-Lewis, Jazmine; Hummel, Eric; Da Rocha, Ulisses Nunes; Chakraborty, Romy; Bowen, Benjamin P.; Karaoz, Ulas; Cadillo-Quiroz, Hinsby; Garcia-Pichel, Ferran; Northen, Trent R.

    2015-09-22

    Soils are arguably the most microbially diverse ecosystems. Physicochemical properties have been associated with the maintenance of this diversity. Yet, the role of microbial substrate specialization is largely unexplored since substrate utilization studies have focused on simple substrates, not the complex mixtures representative of the soil environment. Here we examine the exometabolite composition of desert biological soil crusts (biocrusts) and the substrate preferences of seven biocrust isolates. The biocrust's main primary producer releases a diverse array of metabolites, and isolates of physically associated taxa use unique subsets of the complex metabolite pool. Individual isolates use only 13-26% of available metabolites, with only 2 out of 470 used by all and 40% not used by any. An extension of this approach to a mesophilic soil environment also reveals high levels of microbial substrate specialization. In conclusion, these results suggest that exometabolite niche partitioning may be an important factor in the maintenance of microbial diversity.

  3. Exometabolite niche partitioning among sympatric soil bacteria

    DOE PAGES

    Baran, Richard; Brodie, Eoin L.; Mayberry-Lewis, Jazmine; ...

    2015-09-22

    Soils are arguably the most microbially diverse ecosystems. Physicochemical properties have been associated with the maintenance of this diversity. Yet, the role of microbial substrate specialization is largely unexplored since substrate utilization studies have focused on simple substrates, not the complex mixtures representative of the soil environment. Here we examine the exometabolite composition of desert biological soil crusts (biocrusts) and the substrate preferences of seven biocrust isolates. The biocrust's main primary producer releases a diverse array of metabolites, and isolates of physically associated taxa use unique subsets of the complex metabolite pool. Individual isolates use only 13-26% of available metabolites,more » with only 2 out of 470 used by all and 40% not used by any. An extension of this approach to a mesophilic soil environment also reveals high levels of microbial substrate specialization. In conclusion, these results suggest that exometabolite niche partitioning may be an important factor in the maintenance of microbial diversity.« less

  4. Recursive Partitioning Method on Competing Risk Outcomes

    PubMed Central

    Xu, Wei; Che, Jiahua; Kong, Qin

    2016-01-01

    In some cancer clinical studies, researchers have interests to explore the risk factors associated with competing risk outcomes such as recurrence-free survival. We develop a novel recursive partitioning framework on competing risk data for both prognostic and predictive model constructions. We define specific splitting rules, pruning algorithm, and final tree selection algorithm for the competing risk tree models. This methodology is quite flexible that it can corporate both semiparametric method using Cox proportional hazards model and parametric competing risk model. Both prognostic and predictive tree models are developed to adjust for potential confounding factors. Extensive simulations show that our methods have well-controlled type I error and robust power performance. Finally, we apply both Cox proportional hazards model and flexible parametric model for prognostic tree development on a retrospective clinical study on oropharyngeal cancer patients. PMID:27486300

  5. Partitioned-Interval Quantum Optical Communications Receiver

    NASA Technical Reports Server (NTRS)

    Vilnrotter, Victor A.

    2013-01-01

    The proposed quantum receiver in this innovation partitions each binary signal interval into two unequal segments: a short "pre-measurement" segment in the beginning of the symbol interval used to make an initial guess with better probability than 50/50 guessing, and a much longer segment used to make the high-sensitivity signal detection via field-cancellation and photon-counting detection. It was found that by assigning as little as 10% of the total signal energy to the pre-measurement segment, the initial 50/50 guess can be improved to about 70/30, using the best available measurements such as classical coherent or "optimized Kennedy" detection.

  6. Partitional Classification: A Complement to Phylogeny.

    PubMed

    Salomon, Marc; Dassy, Bruno

    2016-01-01

    The tree of life is currently an active object of research, though next to vertical gene transmission non vertical gene transfers proved to play a significant role in the evolutionary process. To overcome this difficulty, trees of life are now constructed from genes hypothesized vital, on the assumption that these are all transmitted vertically. This view has been challenged. As a frame for this discussion, we developed a partitional taxonomical system clustering taxa at a high taxonomical rank. Our analysis (1) selects RNase P RNA sequences of bacterial, archaeal, and eucaryal genera from genetic databases, (2) submits the sequences, aligned, to k-medoid analysis to obtain clusters, (3) establishes the correspondence between clusters and taxa, (4) constructs from the taxa a new type of taxon, the genetic community (GC), and (5) classifies the GCs: Archaea-Eukaryotes contrastingly different from the six others, all bacterial. The GCs would be the broadest frame to carry out the phylogenies.

  7. Recursive partitioning for heterogeneous causal effects

    PubMed Central

    Athey, Susan; Imbens, Guido

    2016-01-01

    In this paper we propose methods for estimating heterogeneity in causal effects in experimental and observational studies and for conducting hypothesis tests about the magnitude of differences in treatment effects across subsets of the population. We provide a data-driven approach to partition the data into subpopulations that differ in the magnitude of their treatment effects. The approach enables the construction of valid confidence intervals for treatment effects, even with many covariates relative to the sample size, and without “sparsity” assumptions. We propose an “honest” approach to estimation, whereby one sample is used to construct the partition and another to estimate treatment effects for each subpopulation. Our approach builds on regression tree methods, modified to optimize for goodness of fit in treatment effects and to account for honest estimation. Our model selection criterion anticipates that bias will be eliminated by honest estimation and also accounts for the effect of making additional splits on the variance of treatment effect estimates within each subpopulation. We address the challenge that the “ground truth” for a causal effect is not observed for any individual unit, so that standard approaches to cross-validation must be modified. Through a simulation study, we show that for our preferred method honest estimation results in nominal coverage for 90% confidence intervals, whereas coverage ranges between 74% and 84% for nonhonest approaches. Honest estimation requires estimating the model with a smaller sample size; the cost in terms of mean squared error of treatment effects for our preferred method ranges between 7–22%. PMID:27382149

  8. Partition coefficients of organic contaminants with carbohydrates.

    PubMed

    Hung, Hsu-Wen; Lin, Tsair-Fuh; Chiou, Cary T

    2010-07-15

    In view of the current lack of reliable partition coefficients for organic compounds with carbohydrates (K(ch)), carefully measured values with cellulose and starch, the two major forms of carbohydrates, are provided for a wide range of compounds: short-chain chlorinated hydrocarbons, halogenated benzenes, alkyl benzenes, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls, and organochlorine pesticides. To ensure the accuracy of the K(ch) data, solute concentrations in both water and carbohydrate phases are measured by direct solvent extraction of the samples. For a given compound, the observed partition coefficient with cellulose (K(cl)) is virtually the same as that with starch (K(st)). This finding expedites the evaluation of organic contamination with different forms of carbohydrates. The presently determined K(ch) values of 13 PAHs are substantially lower (by 3-66 times) than the literature data; the latter are suspect as they were obtained with (i) presumably impure carbohydrate samples or (ii) indirectly measured equilibrium solute concentrations in carbohydrate and water phases. Although the K(ch) values are generally considerably lower than the respective K(ow) (octanol-water) or K(lipid) (lipid-water), accurate K(ch) data are duly required to accurately estimate the contamination of carbohydrates by organic compounds because of the abundance of carbohydrates over lipids in crops and plants. To overcome the current lack of reliable K(ch) data for organic compounds, a close correlation of log K(ch) with log K(ow) has been established for predicting the unavailable K(ch) data for low-polarity compounds.

  9. Cellulose Deficiency Is Enhanced on Hyper Accumulation of Sucrose by a H+-Coupled Sucrose Symporter1[OPEN

    PubMed Central

    Yeats, Trevor H.; Sorek, Hagit

    2016-01-01

    In order to understand factors controlling the synthesis and deposition of cellulose, we have studied the Arabidopsis (Arabidopsis thaliana) double mutant shaven3 shaven3-like1 (shv3svl1), which was shown previously to exhibit a marked cellulose deficiency. We discovered that exogenous sucrose (Suc) in growth medium greatly enhances the reduction in hypocotyl elongation and cellulose content of shv3svl1. This effect was specific to Suc and was not observed with other sugars or osmoticum. Live-cell imaging of fluorescently labeled cellulose synthase complexes revealed a slowing of cellulose synthase complexes in shv3svl1 compared with the wild type that is enhanced in a Suc-conditional manner. Solid-state nuclear magnetic resonance confirmed a cellulose deficiency of shv3svl1 but indicated that cellulose crystallinity was unaffected in the mutant. A genetic suppressor screen identified mutants of the plasma membrane Suc/H+ symporter SUC1, indicating that the accumulation of Suc underlies the Suc-dependent enhancement of shv3svl1 phenotypes. While other cellulose-deficient mutants were not specifically sensitive to exogenous Suc, the feronia (fer) receptor kinase mutant partially phenocopied shv3svl1 and exhibited a similar Suc-conditional cellulose defect. We demonstrate that shv3svl1, like fer, exhibits a hyperpolarized plasma membrane H+ gradient that likely underlies the enhanced accumulation of Suc via Suc/H+ symporters. Enhanced intracellular Suc abundance appears to favor the partitioning of carbon to starch rather than cellulose in both mutants. We conclude that SHV3-like proteins may be involved in signaling during cell expansion that coordinates proton pumping and cellulose synthesis. PMID:27013021

  10. 47 CFR 24.104 - Partitioning and disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... their authorized spectrum at any time following grant of their geographic area authorizations. (a... names that constitute the partitioned area. (c) Disaggregation. Spectrum may be disaggregated in any... for a partitioned license area and for disaggregated spectrum shall be the remainder of the...

  11. 47 CFR 24.714 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Partitioned licenses and disaggregated spectrum... Partitioned licenses and disaggregated spectrum. (a) Eligibility. (1) Parties seeking approval for... § 24.839. (2) Broadband PCS licensees in spectrum blocks A, B, D, and E and broadband PCS C and F...

  12. 47 CFR 24.714 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Partitioned licenses and disaggregated spectrum... Partitioned licenses and disaggregated spectrum. (a) Eligibility. (1) Parties seeking approval for... § 24.839. (2) Broadband PCS licensees in spectrum blocks A, B, D, and E and broadband PCS C and F...

  13. 47 CFR 22.948 - Partitioning and Disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... partition or disaggregate their spectrum to other qualified entities. (2) Partitioning. During the five year... obtaining disaggregated spectrum may only use such spectrum in that portion of the cellular market encompassed by the original licensee's CGSA and may not use such spectrum to provide service to...

  14. 47 CFR 27.15 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. (1) Parties seeking approval for... service area or disaggregate their licensed spectrum at any time following the grant of their licenses....

  15. 47 CFR 90.365 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Partitioned licenses and disaggregated spectrum... § 90.365 Partitioned licenses and disaggregated spectrum. (a) Eligibility. (1) Party seeking approval... disaggregate their licensed spectrum at any time following the grant of their licenses. Multilateration...

  16. 47 CFR 24.104 - Partitioning and disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... their authorized spectrum at any time following grant of their geographic area authorizations. (a... names that constitute the partitioned area. (c) Disaggregation. Spectrum may be disaggregated in any... for a partitioned license area and for disaggregated spectrum shall be the remainder of the...

  17. 47 CFR 24.104 - Partitioning and disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... their authorized spectrum at any time following grant of their geographic area authorizations. (a... names that constitute the partitioned area. (c) Disaggregation. Spectrum may be disaggregated in any... for a partitioned license area and for disaggregated spectrum shall be the remainder of the...

  18. 47 CFR 24.104 - Partitioning and disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... their authorized spectrum at any time following grant of their geographic area authorizations. (a... names that constitute the partitioned area. (c) Disaggregation. Spectrum may be disaggregated in any... for a partitioned license area and for disaggregated spectrum shall be the remainder of the...

  19. 47 CFR 101.1323 - Spectrum aggregation, disaggregation, and partitioning.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Spectrum aggregation, disaggregation, and... Requirements § 101.1323 Spectrum aggregation, disaggregation, and partitioning. (a) Eligibility. (1) Parties... aggregate spectrum in any MAS bands, but may not disaggregate their licensed spectrum or partition...

  20. 47 CFR 27.15 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. (1) Parties seeking approval for... service area or disaggregate their licensed spectrum at any time following the grant of their licenses....

  1. 47 CFR 24.714 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Partitioned licenses and disaggregated spectrum... Partitioned licenses and disaggregated spectrum. (a) Eligibility. (1) Parties seeking approval for... § 24.839. (2) Broadband PCS licensees in spectrum blocks A, B, D, and E and broadband PCS C and F...

  2. 47 CFR 90.365 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Partitioned licenses and disaggregated spectrum... § 90.365 Partitioned licenses and disaggregated spectrum. (a) Eligibility. (1) Party seeking approval... disaggregate their licensed spectrum at any time following the grant of their licenses. Multilateration...

  3. 47 CFR 90.365 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Partitioned licenses and disaggregated spectrum... § 90.365 Partitioned licenses and disaggregated spectrum. (a) Eligibility. (1) Party seeking approval... disaggregate their licensed spectrum at any time following the grant of their licenses. Multilateration...

  4. 47 CFR 101.1323 - Spectrum aggregation, disaggregation, and partitioning.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Spectrum aggregation, disaggregation, and... Requirements § 101.1323 Spectrum aggregation, disaggregation, and partitioning. (a) Eligibility. (1) Parties... aggregate spectrum in any MAS bands, but may not disaggregate their licensed spectrum or partition...

  5. 47 CFR 22.948 - Partitioning and Disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... partition or disaggregate their spectrum to other qualified entities. (2) Partitioning. During the five year... obtaining disaggregated spectrum may only use such spectrum in that portion of the cellular market encompassed by the original licensee's CGSA and may not use such spectrum to provide service to...

  6. 47 CFR 101.1323 - Spectrum aggregation, disaggregation, and partitioning.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Spectrum aggregation, disaggregation, and... Requirements § 101.1323 Spectrum aggregation, disaggregation, and partitioning. (a) Eligibility. (1) Parties... aggregate spectrum in any MAS bands, but may not disaggregate their licensed spectrum or partition...

  7. 47 CFR 27.15 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. (1) Parties seeking approval for... service area or disaggregate their licensed spectrum at any time following the grant of their licenses....

  8. 47 CFR 22.948 - Partitioning and Disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... partition or disaggregate their spectrum to other qualified entities. (2) Partitioning. During the five year... obtaining disaggregated spectrum may only use such spectrum in that portion of the cellular market encompassed by the original licensee's CGSA and may not use such spectrum to provide service to...

  9. 47 CFR 27.15 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. (a) Eligibility. (1) Parties seeking approval for... service area or disaggregate their licensed spectrum at any time following the grant of their licenses....

  10. 47 CFR 22.948 - Partitioning and Disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... partition or disaggregate their spectrum to other qualified entities. (2) Partitioning. During the five year... obtaining disaggregated spectrum may only use such spectrum in that portion of the cellular market encompassed by the original licensee's CGSA and may not use such spectrum to provide service to...

  11. 47 CFR 24.714 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Partitioned licenses and disaggregated spectrum... Partitioned licenses and disaggregated spectrum. (a) Eligibility. (1) Parties seeking approval for... § 24.839. (2) Broadband PCS licensees in spectrum blocks A, B, D, and E and broadband PCS C and F...

  12. 47 CFR 27.15 - Geographic partitioning and spectrum disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Geographic partitioning and spectrum... Geographic partitioning and spectrum disaggregation. Link to an amendment published at 79 FR 48537, Aug. 15... licensed spectrum at any time following the grant of their licenses. (b) Technical...

  13. 47 CFR 101.1323 - Spectrum aggregation, disaggregation, and partitioning.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Spectrum aggregation, disaggregation, and... Requirements § 101.1323 Spectrum aggregation, disaggregation, and partitioning. (a) Eligibility. (1) Parties... aggregate spectrum in any MAS bands, but may not disaggregate their licensed spectrum or partition...

  14. 47 CFR 101.1323 - Spectrum aggregation, disaggregation, and partitioning.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Spectrum aggregation, disaggregation, and... Requirements § 101.1323 Spectrum aggregation, disaggregation, and partitioning. (a) Eligibility. (1) Parties... aggregate spectrum in any MAS bands, but may not disaggregate their licensed spectrum or partition...

  15. 47 CFR 24.104 - Partitioning and disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... their authorized spectrum at any time following grant of their geographic area authorizations. (a... names that constitute the partitioned area. (c) Disaggregation. Spectrum may be disaggregated in any... for a partitioned license area and for disaggregated spectrum shall be the remainder of the...

  16. 47 CFR 22.948 - Partitioning and Disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... partition or disaggregate their spectrum to other qualified entities. (2) Partitioning. During the five year... obtaining disaggregated spectrum may only use such spectrum in that portion of the cellular market encompassed by the original licensee's CGSA and may not use such spectrum to provide service to...

  17. 47 CFR 24.714 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Partitioned licenses and disaggregated spectrum... Partitioned licenses and disaggregated spectrum. (a) Eligibility. (1) Parties seeking approval for... § 24.839. (2) Broadband PCS licensees in spectrum blocks A, B, D, and E and broadband PCS C and F...

  18. 47 CFR 90.365 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Partitioned licenses and disaggregated spectrum... § 90.365 Partitioned licenses and disaggregated spectrum. (a) Eligibility. (1) Party seeking approval... disaggregate their licensed spectrum at any time following the grant of their licenses. Multilateration...

  19. 47 CFR 90.365 - Partitioned licenses and disaggregated spectrum.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Partitioned licenses and disaggregated spectrum... § 90.365 Partitioned licenses and disaggregated spectrum. (a) Eligibility. (1) Party seeking approval... disaggregate their licensed spectrum at any time following the grant of their licenses. Multilateration...

  20. 47 CFR 101.1111 - Partitioning and disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Partitioning and disaggregation. 101.1111 Section 101.1111 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Competitive Bidding Procedures for LMDS § 101.1111 Partitioning...

  1. 47 CFR 101.1111 - Partitioning and disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Partitioning and disaggregation. 101.1111 Section 101.1111 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Competitive Bidding Procedures for LMDS § 101.1111 Partitioning...

  2. 47 CFR 101.1111 - Partitioning and disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Partitioning and disaggregation. 101.1111 Section 101.1111 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Competitive Bidding Procedures for LMDS § 101.1111 Partitioning...

  3. Spatial partitioning improves the reliability of biochemical signaling

    PubMed Central

    Mugler, Andrew; Tostevin, Filipe; ten Wolde, Pieter Rein

    2013-01-01

    Spatial heterogeneity is a hallmark of living systems, even at the molecular scale in individual cells. A key example is the partitioning of membrane-bound proteins via lipid domain formation or cytoskeleton-induced corralling. However, the impact of this spatial heterogeneity on biochemical signaling processes is poorly understood. Here, we demonstrate that partitioning improves the reliability of biochemical signaling. We exactly solve a stochastic model describing a ubiquitous motif in membrane signaling. The solution reveals that partitioning improves signaling reliability via two effects: it moderates the nonlinearity of the switching response, and it reduces noise in the response by suppressing correlations between molecules. An optimal partition size arises from a trade-off between minimizing the number of proteins per partition to improve signaling reliability and ensuring sufficient proteins per partition to maintain signal propagation. The predicted optimal partition size agrees quantitatively with experimentally observed systems. These results persist in spatial simulations with explicit diffusion barriers. Our findings suggest that molecular partitioning is not merely a consequence of the complexity of cellular substructures, but also plays an important functional role in cell signaling. PMID:23530194

  4. Trace-element partitioning in pantellerites and trachytes

    SciTech Connect

    Mahood, G.A.; Stimac, J.A. )

    1990-08-01

    In order to investigate the effect of increasing melt peralkalinity on partitioning, partition coefficients have been determined using neutron activation analyses of coexisting phenocrysts and glass of five samples from Pantelleria spanning the range trachyte to pantellerite. Alkali feldspar partition coefficients for Fe, Rb, Ba, Sr, and Eu vary with melt peralkalinity due to changes in melt polymerization and to the systematic increase in X{sub or} and decrease in X{sub an} of the feldspar. In going from trachyte to pantellerite, Fe partition coefficients increase from 0.04 to 0.10, presumably because Fe{sup +3} increasingly substitutes in the feldspar tetrahedral site as melt activity of Al declines and Fe concentrations increase. Partition coefficients for trivalent light REEs (rare earth elements) decrease and the partitioning pattern becomes flatter, the most evolved samples having some of the lowest published values for feldspar. The hundredfold decline in Eu partition coefficients (2.5 to 0.024) and the decrease in the size of the positive partitioning anomaly are attributed to increasing Eu{sup 3+}/Eu{sup 2+} in the melt as it becomes more peralkaline, as well as to concomitant decrease in the Ca content of feldspar. As a result, the behavior of Eu during fractional crystallization of peralkaline suites is fundamentally different from that in metaluminous suites; absolute abundances rise and the size of the negative Eu anomaly changes little with fractionation beyond pantelleritic trachyte.

  5. Simple partitions of a hyperbolic plane of positive curvature

    SciTech Connect

    Romakina, Lyudmila N

    2012-09-30

    We construct special monohedral isotropic partitions with symmetries of the hyperbolic plane H of positive curvature with a simple 4-contour as a cell. An analogue of mosaic in these partitions called a tiling is introduced. Also we consider some fractal tilings. The existence of band tilings in each homological series with code (m, n) is proved. Bibliography: 14 titles.

  6. DOES NITROGEN PARTITIONING PROMOTE SPECIES DIVERSITY IN ARCTIC TUSSOCK TUNDRA?

    EPA Science Inventory

    We used 15N soil-labeling techniques to examine how the dominant species in a N-limited, tussock tundra plant community partitioned soil N, and how such partitioning may contribute to community organization. The five most productive species were well differentiated with respect ...

  7. PARTITION COEFFICIENTS FOR METALS IN SURFACE WATER, SOIL, AND WASTE

    EPA Science Inventory

    This report presents metal partition coefficients for the surface water pathway and for the source model used in the Multimedia, Multi-pathway, Multi-receptor Exposure and Risk Assessment (3MRA) technology under development by the U.S. Environmental Protection Agency. Partition ...

  8. ESTIMATING DISSOLVED ORGANIC CARBON PARTITION COEFFICIENTS FOR NONIONIC ORGANIC CHEMICALS

    EPA Science Inventory

    A literature search was performed for dissolved organic carbon/water partition coefficients for nonionic chemicals (Kdoc) and Kdoc data was taken from more than sixty references. The Kdoc data were evaluated as a function of the n-octanol/water partition coefficients (Kow). A pre...

  9. 47 CFR 101.1111 - Partitioning and disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Partitioning and disaggregation. 101.1111 Section 101.1111 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Competitive Bidding Procedures for LMDS § 101.1111 Partitioning...

  10. REE and Strontium Partition Coefficients for Nakhla Pyroxenes

    NASA Technical Reports Server (NTRS)

    Oe, K.; McKay, G.; Le, L.

    2001-01-01

    We present new partition coefficients for REE and Sr determined using a synthetic melt that crystallizes pyroxenes very similar in composition to Nakhla pyroxene cores. We believe these are the most appropriate partition coefficients to use in studying Nakhla Additional information is contained in the original extended abstract..

  11. Solid electrolytes

    DOEpatents

    Abraham, Kuzhikalail M.; Alamgir, Mohamed

    1993-06-15

    This invention pertains to Li ion (Li.sup.+) conductive solid polymer electrolytes composed of solvates of Li salts immobilized (encapsulated) in a solid organic polymer matrix. In particular, this invention relates to solid polymer electrolytes derived by immobilizing complexes (solvates) formed between a Li salt such as LiAsF.sub.6, LiCF.sub.3 SO.sub.3 or LiClO.sub.4 and a mixture of aprotic organic solvents having high dielectric constants such as ethylene carbonate (EC) (dielectric constant=89.6) and propylene carbonate (PC) (dielectric constant=64.4) in a polymer matrix such as polyacrylonitrile, poly(tetraethylene glycol diacrylate), or poly(vinyl pyrrolidinone).

  12. Dominant partition method. [based on a wave function formalism

    NASA Technical Reports Server (NTRS)

    Dixon, R. M.; Redish, E. F.

    1979-01-01

    By use of the L'Huillier, Redish, and Tandy (LRT) wave function formalism, a partially connected method, the dominant partition method (DPM) is developed for obtaining few body reductions of the many body problem in the LRT and Bencze, Redish, and Sloan (BRS) formalisms. The DPM maps the many body problem to a fewer body one by using the criterion that the truncated formalism must be such that consistency with the full Schroedinger equation is preserved. The DPM is based on a class of new forms for the irreducible cluster potential, which is introduced in the LRT formalism. Connectivity is maintained with respect to all partitions containing a given partition, which is referred to as the dominant partition. Degrees of freedom corresponding to the breakup of one or more of the clusters of the dominant partition are treated in a disconnected manner. This approach for simplifying the complicated BRS equations is appropriate for physical problems where a few body reaction mechanism prevails.

  13. Bacterial partition complexes segregate within the volume of the nucleoid

    PubMed Central

    Le Gall, Antoine; Cattoni, Diego I.; Guilhas, Baptiste; Mathieu-Demazière, Céline; Oudjedi, Laura; Fiche, Jean-Bernard; Rech, Jérôme; Abrahamsson, Sara; Murray, Heath; Bouet, Jean-Yves; Nollmann, Marcelo

    2016-01-01

    Precise and rapid DNA segregation is required for proper inheritance of genetic material. In most bacteria and archaea, this process is assured by a broadly conserved mitotic-like apparatus in which a NTPase (ParA) displaces the partition complex. Competing observations and models imply starkly different 3D localization patterns of the components of the partition machinery during segregation. Here we use super-resolution microscopies to localize in 3D each component of the segregation apparatus with respect to the bacterial chromosome. We show that Par proteins locate within the nucleoid volume and reveal that proper volumetric localization and segregation of partition complexes requires ATPase and DNA-binding activities of ParA. Finally, we find that the localization patterns of the different components of the partition system highly correlate with dense chromosomal regions. We propose a new mechanism in which the nucleoid provides a scaffold to guide the proper segregation of partition complexes. PMID:27377966

  14. Nutrient partitioning and seedling development in the genus Leucaena

    SciTech Connect

    Dovel, R.L.

    1987-01-01

    Slow establishment of the genus Leucaena from seed has been attributed to law seedling vigor and late nodulation. Observation of early seedling growth indicated that partitioning of a large proportion of resources to the root of young Leucaena seedlings could account, in part, for the slow initial shoot growth observed in this genus. Therefore, a series of experiments were conducted to examine the partitioning of stored seed reserves, photosynthate, and nitrogen in developing Leucaena seedlings. The effects of nodulation and nitrogen fertilization on partitioning of nutrients in the seedling were also examined. Seed reserves were initially used for radicle growth in dark grown seedlings; however, partitioning soon shifted to the hypocotyl. By four days after imbibition, hypocotyl weight exceeded radicle weight in both species tested (L. leucocephala and L. retusa), at all temperatures above 20/sup 0/C. Two experiments were conducted examining the carbon partitioning of L. leucocephala cultivar K-8 using /sup 14/CO/sub 2/ pulse labeling techniques.

  15. Partitioning in Avionics Architectures: Requirements, Mechanisms, and Assurance

    NASA Technical Reports Server (NTRS)

    Rushby, John

    1999-01-01

    Automated aircraft control has traditionally been divided into distinct "functions" that are implemented separately (e.g., autopilot, autothrottle, flight management); each function has its own fault-tolerant computer system, and dependencies among different functions are generally limited to the exchange of sensor and control data. A by-product of this "federated" architecture is that faults are strongly contained within the computer system of the function where they occur and cannot readily propagate to affect the operation of other functions. More modern avionics architectures contemplate supporting multiple functions on a single, shared, fault-tolerant computer system where natural fault containment boundaries are less sharply defined. Partitioning uses appropriate hardware and software mechanisms to restore strong fault containment to such integrated architectures. This report examines the requirements for partitioning, mechanisms for their realization, and issues in providing assurance for partitioning. Because partitioning shares some concerns with computer security, security models are reviewed and compared with the concerns of partitioning.

  16. Crystal/liquid partitioning in augite - Effects of cooling rate

    NASA Astrophysics Data System (ADS)

    Gamble, R. P.; Taylor, L. A.

    1980-03-01

    The partitioning of major and minor elements between augite and melt was determined as a function of cooling rate for two high-titanium basalt compositions. The results of this study of lunar rock systems 10017 and 75055 were compared with the results of other kinetic studies of augite-liquid partitioning in other rock systems. It was found that the partitioning of major elements (i.e., Ca, Fe, Mg) is essentially rate independent and is insensitive to bulk rock composition and to the nature and order of appearance of coexisting phases for cooling rates of less than 100 C/hr. The partitioning behavior of minor elements (i.e., Al, Cr, Ti) for the same range of cooling rates is complex, being dependent on cooling rate and bulk rock composition. Consideration of these factors is important when augite chemistry and/or partitioning behavior are used in modeling certain magmatic processes or in estimating the thermal history of basaltic rocks.

  17. Pyroclast acceleration and energy partitioning in fake explosive eruptions

    NASA Astrophysics Data System (ADS)

    Gaudin, Damien; Taddeucci, Jacopo; Scheu, Bettina; Valentine, Greg; Capponi, Antonio; Kueppers, Ulrich; Graettiger, Allison; Sonder, Ingo

    2014-05-01

    Explosive eruptions are characterized by the fast release of energy, with gas expansion playing a lead role. An excess of pressure may be generated either by the exsolution and accumulation of volatiles (e.g., vulcanian and strombolian explosions) or by in situ vaporization of water (e.g., phreato-magmatic explosions). The release of pressurized gas ejects magma and country rock pyroclasts at velocities that can reach several hundred of meters per second. The amount and velocity of pyroclasts is determined not only by the total released energy, but also by the system-specific dynamics of the energy transfer from gas to pyroclasts. In this context, analogue experiments are crucial, since the amount of available energy is determined. Here, we analyze three different experiments, designed to reproduce different aspects of explosive volcanism, focusing on the acceleration phase of the pyroclasts, in order to compare how the potential energy is transferred to the pyroclasts in different systems. In the first, shock-tube-type experiment, salt crystals resting in a pressurized Plexiglas cylinder are accelerated when a diaphragm set is suddenly opened, releasing the gas. In the second experiment, a pressurized air bubble is released in a water-filled Plexiglas pipe; diaphragm opening causes sudden expansion and bursting of the bubble and ejection of water droplets. In the last experiment, specifically focusing on phreatomagmatic eruptions, buried explosive charges accelerate the overlying loose material. All experiments were monitored by multiple high speed cameras and a variety of sensors. Despite the largely differing settings and processes, particle ejection velocity above the vent from the three experiments share a non-linear decay over time. Fitting this decay allows to estimate a characteristic depth that is related to the specific acceleration processes. Given that the initial available energy is experimentally controlled a priori, the information on the

  18. Metallothionein-induced zinc partitioning exacerbates hyperoxic acute lung injury

    PubMed Central

    Lee, Sang-Min; McLaughlin, Joseph N.; Frederick, Daniel R.; Zhu, Lin; Thambiayya, Kalidasan; Wasserloos, Karla J.; Kaminski, Iris; Pearce, Linda L.; Peterson, Jim; Li, Jin; Latoche, Joseph D.; Peck Palmer, Octavia M.; Stolz, Donna Beer; Fattman, Cheryl L.; Alcorn, John F.; Oury, Tim D.; Angus, Derek C.; Pitt, Bruce R.

    2013-01-01

    Hypozincemia, with hepatic zinc accumulation at the expense of other organs, occurs in infection, inflammation, and aseptic lung injury. Mechanisms underlying zinc partitioning or its impact on extrahepatic organs are unclear. Here we show that the major zinc-binding protein, metallothionein (MT), is critical for zinc transmigration from lung to liver during hyperoxia and preservation of intrapulmonary zinc during hyperoxia is associated with an injury-resistant phenotype in MT-null mice. Particularly, lung-to-liver zinc ratios decreased in wild-type (WT) and increased significantly in MT-null mice breathing 95% oxygen for 72 h. Compared with female adult WT mice, MT-null mice were significantly protected against hyperoxic lung injury indicated by reduced inflammation and interstitial edema, fewer necrotic changes to distal airway epithelium, and sustained lung function at 72 h hyperoxia. Lungs of MT-null mice showed decreased levels of immunoreactive LC3, an autophagy marker, compared with WT mice. Analysis of superoxide dismutase (SOD) activity in the lungs revealed similar levels of manganese-SOD activity between strains under normoxia and hyperoxia. Lung extracellular SOD activity decreased significantly in both strains at 72 h of hyperoxia, although there was no difference between strains. Copper-zinc-SOD activity was ∼4× higher under normoxic conditions in MT-null compared with WT mice but was not affected in either group by hyperoxia. Collectively the data suggest that genetic deletion of MT-I/II in mice is associated with compensatory increase in copper-zinc-SOD activity, prevention of hyperoxia-induced zinc transmigration from lung to liver, and hyperoxia-resistant phenotype strongly associated with differences in zinc homeostasis during hyperoxic acute lung injury. PMID:23275622

  19. Re-analysis of narcotic critical body residue data using the equilibrium distribution concept and refined partition coefficients.

    PubMed

    Endo, Satoshi

    2016-08-10

    Narcosis occurs as a result of the accumulation of chemicals in the phospholipid membrane. The toxic threshold concentration in the membrane is thought to be relatively constant across different chemicals and species. Hence, estimating chemical concentrations in the membrane is expected to reduce the variability of narcotic critical body residue (CBR) data. In this study, a high quality CBR dataset for three aquatic species reported recently in the literature was evaluated with the internal equilibrium distribution concept. The raw wet-weight-based CBR values were converted to membrane-weight-based CBR values by assuming that the chemical is distributed in storage lipids, membranes, proteins, and water according to the respective equilibrium partition coefficients. Several sets of partition coefficients were compared for this analysis. The results were consistent with the notion that the use of a structural protein instead of serum albumin as a surrogate for the body protein fraction could reduce the variability of CBRs. Partition coefficients predicted by polyparameter linear free energy relationships (PP-LFERs) reduced the variability of CBRs as much as or even more than experimental partition coefficients did. It is suggested that CBR data for chemicals with larger structural diversity and biological species with more distinct compositions are needed to evaluate further the equilibrium distribution concept and the constant membrane threshold hypothesis.

  20. THE OCCURRENCE OF CONTAMINANT ACCUMULATION IN LEAD PIPE SCALES FROM DOMESTIC DRINKING WATER DISTRIBUTION SYSTEMS

    EPA Science Inventory

    Previous work has shown that contaminants, such as Al, As and Ra, can accumulate in drinking water distribution system solids. The release of accumulated contaminants back into the water supply could result in elevated levels at consumers’ taps, and current monitoring practices d...

  1. Immiscible silicate liquid partition coefficients: implications for crystal-melt element partitioning and basalt petrogenesis

    NASA Astrophysics Data System (ADS)

    Veksler, Ilya V.; Dorfman, Alexander M.; Danyushevsky, Leonid V.; Jakobsen, Jakob K.; Dingwell, Donald B.

    2006-12-01

    This study investigates partitioning of elements between immiscible aluminosilicate and borosilicate liquids using three synthetic mixtures doped with 32 trace elements. In order to get a good spatial separation of immiscible liquids, we employed a high-temperature centrifuge. Experiments were performed at 1,050-1,150°C, 1 atm, in sealed Fe and Pt containers. Quenched products were analysed by electron microprobe and LA ICP-MS. Nernst partition coefficients ( D’s) between the Fe-rich and Si-rich aluminosilicate immiscible liquids are the highest for Zn (3.3) and Fe (2.6) and the lowest for Rb and K (0.4-0.5). The plots of D values against ionic potential Z/r in all the compositions show a convex upward trend, which is typical also for element partitioning between immiscible silicate and salt melts. The results bear upon the speciation and structural position of elements in multicomponent silicate liquids. The ferrobasalt-rhyolite liquid immiscibility is observed in evolved basaltic magmas, and may play an important role in large gabbroic intrusions, such as Skaergaard, and during the generation of unusual lavas, such as ferropicrites.

  2. Noise Reduction by Signal Accumulation

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2006-01-01

    The aim of this paper is to show how the noise reduction by signal accumulation can be accomplished with a data acquisition system. This topic can be used for student projects. In many cases, the noise reduction is an unavoidable part of experimentation. Several techniques are known for this purpose, and among them the signal accumulation is the…

  3. Solid lipid microparticles containing loratadine prepared using a Micromixer.

    PubMed

    Milak, Spomenka; Medlicott, Natalie; Tucker, Ian G

    2006-12-01

    Solid lipid microparticles were investigated as a taste-masking approach for a lipophilic weak base in a suspension. The idea was that the drug concentration in the aqueous phase of a suspension might be reduced by its partitioning into the solid lipid particles. Loratadine, as a model drug, was used to prepare Precirol ATO 5 microparticles by a Micromixer. The effects of three process variables: drug loading, PVA concentration and water/lipid ratio on the microparticle size, encapsulation efficiency, surface appearance, in-vitro release and drug partitioning in a suspension were studied. Loratadine release was slow in simulated saliva and very fast at the pH of stomach. In suspension of loratadine lipid microparticles, drug was released into the aqueous phase to the same concentration as in a drug suspension. Therefore, the usefulness of these microparticles for taste-masking in liquids is limited. However, they might be useful for taste-masking in solid dosage forms.

  4. Polyacrylate-water partitioning of biocidal compounds: enhancing the understanding of biocide partitioning between render and water.

    PubMed

    Bollmann, Ulla E; Ou, Yi; Mayer, Philipp; Trapp, Stefan; Bester, Kai

    2015-01-01

    In recent years, the application of polymer-based renders and paints for façade coatings of buildings has risen enormously due to the increased mounting of thermal insulation systems. These materials are commonly equipped with biocides - algaecides, fungicides, and bactericides - to protect the materials from biological deterioration. However, the biocides need to be present in the water phase in order to be active and, hence, they are flushed of the material by rain water. In order to increase the knowledge about the partitioning of biocides from render into the water phase, partition constants between the polymer - in this case polyacrylate - and water were studied using glass fibre filters coated with polyacrylate. The polyacrylate-water partition constants (logKAcW) of ten biocides used in construction material varied between 1.66 (isoproturon) and 3.57 (dichloro-N-octylisothiazolinone). The correlation of the polyacrylate-water partition constants with the octanol-water partition constants is significant, but the polyacrylate-water partition constants were predominantly below octanol-water partition constants (Kow). The comparison with render-water distribution constants showed that estimating the leaching of biocides from render based on polymer-water partitioning is a useful and practical tool.

  5. New Linear Partitioning Models Based on Experimental Water: Supercritical CO 2 Partitioning Data of Selected Organic Compounds

    SciTech Connect

    Burant, Aniela; Thompson, Christopher; Lowry, Gregory V.; Karamalidis, Athanasios K.

    2016-05-17

    Partitioning coefficients of organic compounds between water and supercritical CO2 (sc-CO2) are necessary to assess the risk of migration of these chemicals from subsurface CO2 storage sites. Despite the large number of potential organic contaminants, the current data set of published water-sc-CO2 partitioning coefficients is very limited. Here, the partitioning coefficients of thiophene, pyrrole, and anisole were measured in situ over a range of temperatures and pressures using a novel pressurized batch reactor system with dual spectroscopic detectors: a near infrared spectrometer for measuring the organic analyte in the CO2 phase, and a UV detector for quantifying the analyte in the aqueous phase. Our measured partitioning coefficients followed expected trends based on volatility and aqueous solubility. The partitioning coefficients and literature data were then used to update a published poly-parameter linear free energy relationship and to develop five new linear free energy relationships for predicting water-sc-CO2 partitioning coefficients. Four of the models targeted a single class of organic compounds. Unlike models that utilize Abraham solvation parameters, the new relationships use vapor pressure and aqueous solubility of the organic compound at 25 °C and CO2 density to predict partitioning coefficients over a range of temperature and pressure conditions. The compound class models provide better estimates of partitioning behavior for compounds in that class than the model built for the entire dataset.

  6. Flow Partitioning in Fully Saturated Soil Aggregates

    SciTech Connect

    Yang, Xiaofan; Richmond, Marshall C.; Scheibe, Timothy D.; Perkins, William A.; Resat, Haluk

    2014-03-30

    Microbes play an important role in facilitating organic matter decomposition in soils, which is a major component of the global carbon cycle. Microbial dynamics are intimately coupled to environmental transport processes, which control access to labile organic matter and other nutrients that are needed for the growth and maintenance of microorganisms. Transport of soluble nutrients in the soil system is arguably most strongly impacted by preferential flow pathways in the soil. Since the physical structure of soils can be characterized as being formed from constituent micro aggregates which contain internal porosity, one pressing question is the partitioning of the flow among the “inter-aggregate” and “intra-aggregate” pores and how this may impact overall solute transport within heterogeneous soil structures. The answer to this question is particularly important in evaluating assumptions to be used in developing upscaled simulations based on highly-resolved mechanistic models. We constructed a number of diverse multi-aggregate structures with different packing ratios by stacking micro-aggregates containing internal pores and varying the size and shape of inter-aggregate pore spacing between them. We then performed pore-scale flow simulations using computational fluid dynamics methods to determine the flow patterns in these aggregate-of-aggregates structures and computed the partitioning of the flow through intra- and inter-aggregate pores as a function of the spacing between the aggregates. The results of these numerical experiments demonstrate that soluble nutrients are largely transported via flows through inter-aggregate pores. Although this result is consistent with intuition, we have also been able to quantify the relative flow capacity of the two domains under various conditions. For example, in our simulations, the flow capacity through the aggregates (intra-aggregate flow) was less than 2% of the total flow when the spacing between the aggregates

  7. Scheduling Independent Partitions in Integrated Modular Avionics Systems

    PubMed Central

    Du, Chenglie; Han, Pengcheng

    2016-01-01

    Recently the integrated modular avionics (IMA) architecture has been widely adopted by the avionics industry due to its strong partition mechanism. Although the IMA architecture can achieve effective cost reduction and reliability enhancement in the development of avionics systems, it results in a complex allocation and scheduling problem. All partitions in an IMA system should be integrated together according to a proper schedule such that their deadlines will be met even under the worst case situations. In order to help provide a proper scheduling table for all partitions in IMA systems, we study the schedulability of independent partitions on a multiprocessor platform in this paper. We firstly present an exact formulation to calculate the maximum scaling factor and determine whether all partitions are schedulable on a limited number of processors. Then with a Game Theory analogy, we design an approximation algorithm to solve the scheduling problem of partitions, by allowing each partition to optimize its own schedule according to the allocations of the others. Finally, simulation experiments are conducted to show the efficiency and reliability of the approach proposed in terms of time consumption and acceptance ratio. PMID:27942013

  8. Graph Partitioning for Parallel Applications in Heterogeneous Grid Environments

    NASA Technical Reports Server (NTRS)

    Bisws, Rupak; Kumar, Shailendra; Das, Sajal K.; Biegel, Bryan (Technical Monitor)

    2002-01-01

    The problem of partitioning irregular graphs and meshes for parallel computations on homogeneous systems has been extensively studied. However, these partitioning schemes fail when the target system architecture exhibits heterogeneity in resource characteristics. With the emergence of technologies such as the Grid, it is imperative to study the partitioning problem taking into consideration the differing capabilities of such distributed heterogeneous systems. In our model, the heterogeneous system consists of processors with varying processing power and an underlying non-uniform communication network. We present in this paper a novel multilevel partitioning scheme for irregular graphs and meshes, that takes into account issues pertinent to Grid computing environments. Our partitioning algorithm, called MiniMax, generates and maps partitions onto a heterogeneous system with the objective of minimizing the maximum execution time of the parallel distributed application. For experimental performance study, we have considered both a realistic mesh problem from NASA as well as synthetic workloads. Simulation results demonstrate that MiniMax generates high quality partitions for various classes of applications targeted for parallel execution in a distributed heterogeneous environment.

  9. Scheduling Independent Partitions in Integrated Modular Avionics Systems.

    PubMed

    Chen, Jinchao; Du, Chenglie; Han, Pengcheng

    2016-01-01

    Recently the integrated modular avionics (IMA) architecture has been widely adopted by the avionics industry due to its strong partition mechanism. Although the IMA architecture can achieve effective cost reduction and reliability enhancement in the development of avionics systems, it results in a complex allocation and scheduling problem. All partitions in an IMA system should be integrated together according to a proper schedule such that their deadlines will be met even under the worst case situations. In order to help provide a proper scheduling table for all partitions in IMA systems, we study the schedulability of independent partitions on a multiprocessor platform in this paper. We firstly present an exact formulation to calculate the maximum scaling factor and determine whether all partitions are schedulable on a limited number of processors. Then with a Game Theory analogy, we design an approximation algorithm to solve the scheduling problem of partitions, by allowing each partition to optimize its own schedule according to the allocations of the others. Finally, simulation experiments are conducted to show the efficiency and reliability of the approach proposed in terms of time consumption and acceptance ratio.

  10. Gypsum accumulation on carbonate stone

    USGS Publications Warehouse

    McGee, E.S.; Mossotti, V.G.

    1992-01-01

    The accumulation of gypsum on carbonate stone has been investigated through exposure of fresh samples of limestone and marble at monitored sites, through examination of alteration crusts from old buildings and through laboratory experiments. Several factors contribute to gypsum accumulation on carbonate stone. Marble or limestone that is sheltered from direct washing by rain in an urban environment with elevated pollution levels is likely to accumulate a gypsum crust. Crust development may be enhanced if the stone is porous or has an irregular surface area. Gypsum crusts are a surficial alteration feature; gypsum crystals form at the pore opening-air interface, where evaporation is greatest.

  11. Partitioning taxonomic diversity of aquatic insect assemblages ...

    EPA Pesticide Factsheets

    Biological diversity can be divided into: alpha (α, local), beta (β, difference in assemblage composition among locals), and gamma (γ, total diversity). We assessed the partitioning of taxonomic diversity of Ephemeroptera, Plecoptera and Trichoptera (EPT) and of functional feeding groups (FFG) in Neotropical Savanna (southeastern Brazilian Cerrado) streams. To do so, we considered three diversity components: stream site (α), among stream sites (β1), and among hydrologic units (β2). We also evaluated the association of EPT genera composition with heterogeneity in land use, instream physical habitat structure, and instream water quality variables. The percent of EPT taxonomic α diversity (20.7%) was lower than the β1 and β2 diversities (53.1% and 26.2%, respectively). The EPT FFG α diversity (26.5%) was lower than the β1 diversity (55.8%) and higher than the β2 (17.7%) diversity. The collector-gatherer FFG was predominant and had the greatest β diversity among stream sites (β1, 55.8%). Our findings support the need for implementing regional scale conservation strategies in the Cerrado biome, which has been degraded by anthropogenic activities. Using adaptations of the US EPA’s National Aquatic Resource Survey (NARS) designs and methods, Ferreira and colleagues examined the distribution of taxonomic and functional diversity of aquatic insects among basins, stream sites within basins, and within stream sample reaches. They sampled 160 low-order stre

  12. Kinetic partitioning mechanism of HDV ribozyme folding.

    PubMed

    Chen, Jiawen; Gong, Sha; Wang, Yujie; Zhang, Wenbing

    2014-01-14

    RNA folding kinetics is directly tied to RNA biological functions. We introduce here a new approach for predicting the folding kinetics of RNA secondary structure with pseudoknots. This approach is based on our previous established helix-based method for predicting the folding kinetics of RNA secondary structure. In this approach, the transition rates for an elementary step: (1) formation, (2) disruption of a helix stem, and (3) helix formation with concomitant partial melting of an incompatible helix, are calculated with the free energy landscape. The folding kinetics of the Hepatitis delta virus (HDV) ribozyme and the mutated sequences are studied with this method. The folding pathways are identified by recursive searching the states with high net flux-in(out) population starting from the native state. The theory results are in good agreement with that of the experiments. The results indicate that the bi-phasic folding kinetics for the wt HDV sequence is ascribed to the kinetic partitioning mechanism: Part of the population will quickly fold to the native state along the fast pathway, while another part of the population will fold along the slow pathway, in which the population is trapped in a non-native state. Single mutation not only changes the folding rate but also the folding pathway.

  13. Liquid centrifugation for nuclear waste partitioning

    SciTech Connect

    Bowman, C.D.

    1992-03-11

    The performance of liquid centrifugation for nuclear waste partitioning is examined for the Accelerator Transmutation of Waste Program currently under study at the Los Alamos National Laboratory. Centrifugation might have application for the separation of the LiF-BeF{sub 2} salt from heavier radioactive materials fission product and actinides in the separation of fission product from actinides, in the isotope separation of fission-product cesium before transmutation of the {sup 137}Cs and {sup 135}Cs, and in the removal of spallation product from the liquid lead target. It is found that useful chemical separations should be possible using existing materials for the centrifuge construction for all four cases with the actinide fraction in fission product perhaps as low as 1 part in 10{sup 7} and the fraction of {sup 137}CS in {sup 133}Cs being as low as a few parts in 10{sup 5}. A centrifuge cascade has the advantage that it can be assembled and operated as a completely closed system without a waste stream except that associated with maintenance or replacement of centrifuge components.

  14. A Non-conventional Watershed Partitioning Method

    NASA Astrophysics Data System (ADS)

    Menduni, Giovanni; Pagani, Alessandro; Rulli, Maria Cristina; Rossso, Renzo

    The extraction of the river network from a Digital Elevation Model (DEM) plays a fundamental role in modelling spatially distributed hydrological processes. This ex- ercise deals with a new two-step procedure based on the preliminary identification of an Ideal Drainage Network (IDN) from contour lines trough a variable mesh size, and the further extraction of the Actual Drainage Network (AND) from the IDN using land morphology. The steepest downslope lines search is used to identify individual channels, which are further merged into a network path draining to a given node of the IDN. The contributing area, peaks and saddles are determined by means of steepest upslope lines search. The basin area is thus partitioned into physically based finite ele- ments enclosed by irregular polygons. Different methods, i.e. the constant and variable threshold area method, the contour line curvature method, and a topologic method de- scending from the Hortonian ordering scheme are used to extract the Actual Drainage Network (ADN) from the IDN. Accordingly, using of the contour line curvature is shown to provide the most appropriate method from comparison with field surveys.

  15. Kinetic partitioning mechanism of HDV ribozyme folding

    SciTech Connect

    Chen, Jiawen; Gong, Sha; Wang, Yujie; Zhang, Wenbing

    2014-01-14

    RNA folding kinetics is directly tied to RNA biological functions. We introduce here a new approach for predicting the folding kinetics of RNA secondary structure with pseudoknots. This approach is based on our previous established helix-based method for predicting the folding kinetics of RNA secondary structure. In this approach, the transition rates for an elementary step: (1) formation, (2) disruption of a helix stem, and (3) helix formation with concomitant partial melting of an incompatible helix, are calculated with the free energy landscape. The folding kinetics of the Hepatitis delta virus (HDV) ribozyme and the mutated sequences are studied with this method. The folding pathways are identified by recursive searching the states with high net flux-in(out) population starting from the native state. The theory results are in good agreement with that of the experiments. The results indicate that the bi-phasic folding kinetics for the wt HDV sequence is ascribed to the kinetic partitioning mechanism: Part of the population will quickly fold to the native state along the fast pathway, while another part of the population will fold along the slow pathway, in which the population is trapped in a non-native state. Single mutation not only changes the folding rate but also the folding pathway.

  16. Kinetic partitioning mechanism of HDV ribozyme folding

    NASA Astrophysics Data System (ADS)

    Chen, Jiawen; Gong, Sha; Wang, Yujie; Zhang, Wenbing

    2014-01-01

    RNA folding kinetics is directly tied to RNA biological functions. We introduce here a new approach for predicting the folding kinetics of RNA secondary structure with pseudoknots. This approach is based on our previous established helix-based method for predicting the folding kinetics of RNA secondary structure. In this approach, the transition rates for an elementary step: (1) formation, (2) disruption of a helix stem, and (3) helix formation with concomitant partial melting of an incompatible helix, are calculated with the free energy landscape. The folding kinetics of the Hepatitis delta virus (HDV) ribozyme and the mutated sequences are studied with this method. The folding pathways are identified by recursive searching the states with high net flux-in(out) population starting from the native state. The theory results are in good agreement with that of the experiments. The results indicate that the bi-phasic folding kinetics for the wt HDV sequence is ascribed to the kinetic partitioning mechanism: Part of the population will quickly fold to the native state along the fast pathway, while another part of the population will fold along the slow pathway, in which the population is trapped in a non-native state. Single mutation not only changes the folding rate but also the folding pathway.

  17. Linear Time Vertex Partitioning on Massive Graphs.

    PubMed

    Mell, Peter; Harang, Richard; Gueye, Assane

    The problem of optimally removing a set of vertices from a graph to minimize the size of the largest resultant component is known to be NP-complete. Prior work has provided near optimal heuristics with a high time complexity that function on up to hundreds of nodes and less optimal but faster techniques that function on up to thousands of nodes. In this work, we analyze how to perform vertex partitioning on massive graphs of tens of millions of nodes. We use a previously known and very simple heuristic technique: iteratively removing the node of largest degree and all of its edges. This approach has an apparent quadratic complexity since, upon removal of a node and adjoining set of edges, the node degree calculations must be updated prior to choosing the next node. However, we describe a linear time complexity solution using an array whose indices map to node degree and whose values are hash tables indicating the presence or absence of a node at that degree value. This approach also has a linear growth with respect to memory usage which is surprising since we lowered the time complexity from quadratic to linear. We empirically demonstrate linear scalability and linear memory usage on random graphs of up to 15000 nodes. We then demonstrate tractability on massive graphs through execution on a graph with 34 million nodes representing Internet wide router connectivity.

  18. Niche partitioning of closely related symbiotic dinoflagellates.

    PubMed

    Sampayo, Eugenia M; Franceschinis, Lorenzo; Hoegh-Guldberg, Ove; Dove, Sophie

    2007-09-01

    Reef-building corals are fundamental to the most diverse marine ecosystems, yet a detailed understanding of the processes involved in the establishment, persistence and ecology of the coral-dinoflagellate association remains largely unknown. This study explores symbiont diversity in relation to habitat by employing a broad-scale sampling regime using ITS2 and denaturing gradient gel electrophoresis. Samples from Pocillopora damicornis, Stylophora pistillata and Seriatopora hystrix all harboured host-specific clade C symbiont types at Heron Island (Great Barrier Reef, Australia). While Ser. hystrix associated with a single symbiont profile along its entire depth distribution, both P. damicornis and Sty. pistillata associated with multiple symbiont profiles that showed a strong zonation with depth. It is shown that, with an increased sampling effort, previously identified 'rare' symbiont types within this group of host species are in fact environmental specialists. A multivariate approach was used to expand on the common distinction of symbionts by a single genetic identity. It shows merit in its capacity not only to include all the variability present within the marker region but also to reliably represent ecological diversification of symbionts. Furthermore, the cohesive species concept is explored to explain how niche partitioning may drive diversification of closely related symbiont lineages. This study provides thus evidence that closely related symbionts are ecologically distinct and fulfil their own niche within the ecosystem provided by the host and external environment.

  19. Assimilate partitioning in avocado, Persea americana

    SciTech Connect

    Finazzo, S.; Davenport, T.L.

    1986-04-01

    Assimilate partitioning is being studied in avocado, Persea americana cv. Millborrow in relation to fruit set. Single leaves on girdled branches of 10 year old trees were radiolabeled for 1 hr with 13..mu..Ci of /sup 14/CO/sub 2/. The source leaves were sampled during the experiment to measure translocation rates. At harvest the sink tissues were dissected and the incorporated radioactivity was measured. The translocation of /sup 14/C-labelled compounds to other leaves was minimal. Incorporation of label into fruitlets varied with the tissue and the stage of development. Sink (fruitlets) nearest to the labelled leaf and sharing the same phyllotaxy incorporated the most /sup 14/C. Source leaves for single non-abscising fruitlets retained 3X more /sup 14/C-labelled compounds than did source leaves for 2 or more fruitlets at 31 hrs. post-labelling. Export of label decreased appreciably when fruitlets abscised. If fruitlets abscised within 4 days of labeling then the translocation pattern was similar to the pattern for single fruitlets. If the fruitlet abscised later, the translocation pattern was intermediate between the single and double fruitlet pattern.

  20. Video partitioning by segmenting moving object trajectories

    NASA Astrophysics Data System (ADS)

    Badal, Tapas; Nain, Neeta; Ahmed, Mushtaq

    2015-02-01

    Video partitioning may be involve in a number of applications and present solutions for monitoring and tracking particular person trajectory and also helps in to generate semantic analysis of single entity or of entire video. Many recent advances in object detection and tracking concern about motion structure and data association used to be assigned a label to trajectories and analyze them independently. In this work we propose an approach for video portioning and a structure is given to store motion structure of target set to monitor in video. Spatio-temporal tubes separate individual objects that help to generate semantic analysis report for each object individually. The semantic analysis system for video based on this framework provides not only efficient synopsis generation but also spatial collision where the temporal consistency can be resolved for representation of semantic knowledge of each object. For keeping low computational complexity trajectories are generated online and classification, knowledge representation and arrangement over spatial domain are suggested to perform in offline manner.

  1. Resource partitioning by insectivorous bats in Jamaica.

    PubMed

    Emrich, Matthew A; Clare, Elizabeth L; Symondson, William O C; Koenig, Susan E; Fenton, Melville Brock

    2014-08-01

    In this investigation, we use variation in wing morphology, echolocation behaviour, patterns of habitat use and molecular diet analysis to demonstrate that six species of sympatric insectivorous bats in Jamaica show significant differences that could explain resource partitioning among the species. High-intensity echolocating species that used shorter, broadband signals and had shorter, broader wings (Pteronotus macleayii, Pteronotus quadridens, Mormoops blainvillii) foraged most in edge habitats, but differed in timing of peak activity. P. macleayii and M. blainvillii differed in diet, but low sample size precluded diet analysis for P. quadridens. High-intensity echolocating species that used longer, more narrowband signals and had longer, narrower wings (Molossus molossus, Tadarida brasiliensis) foraged most in open areas and differed in diet from the other species. Two disparate species were most active in clutter (dense vegetation). Pteronotus parnellii used high-duty-cycle echolocation apparently specialized for detecting fluttering targets in clutter. Macrotus waterhousii used low-intensity, broadband echolocation calls and presumably uses prey-generated sounds when foraging. These two species also differed in diet. Our data show that differences in morphology and echolocation behaviour coincide with differences in habitat use and diet, resulting in minimal overlap in resource use among species.

  2. Partitioning a Gridded Rectangle into Smaller Rectangles

    NASA Technical Reports Server (NTRS)

    Klimesh, Matthew; Kiely, Aaron

    2004-01-01

    A relatively simple algorithm, devised for use in an image-data-compression application, partitions a rectangular pixelated image (or any other rectangle on which a regular rectangular grid has already been superimposed) into a specified number of smaller rectangles, hereafter denoted segments. The algorithm has the following properties: No floating-point operations are needed. The segments tend to be nearly square (in the sense that their widths and heights in pixel units tend to be nearly equal). The segments tend to have nearly equal areas. The algorithm yields valid results (no zero-width or zero-height segments) as long as the specified number of segments, s, does not exceed the number of pixels (equivalently, the number of grid cells). The inputs to the algorithm are the positive integer s plus the positive integers h and w, denoting the height and width, respectively, of the rectangle in pixel units. The limit on s for a valid result is given by s less than or equal to wh.

  3. Linear Time Vertex Partitioning on Massive Graphs

    PubMed Central

    Mell, Peter; Harang, Richard; Gueye, Assane

    2016-01-01

    The problem of optimally removing a set of vertices from a graph to minimize the size of the largest resultant component is known to be NP-complete. Prior work has provided near optimal heuristics with a high time complexity that function on up to hundreds of nodes and less optimal but faster techniques that function on up to thousands of nodes. In this work, we analyze how to perform vertex partitioning on massive graphs of tens of millions of nodes. We use a previously known and very simple heuristic technique: iteratively removing the node of largest degree and all of its edges. This approach has an apparent quadratic complexity since, upon removal of a node and adjoining set of edges, the node degree calculations must be updated prior to choosing the next node. However, we describe a linear time complexity solution using an array whose indices map to node degree and whose values are hash tables indicating the presence or absence of a node at that degree value. This approach also has a linear growth with respect to memory usage which is surprising since we lowered the time complexity from quadratic to linear. We empirically demonstrate linear scalability and linear memory usage on random graphs of up to 15000 nodes. We then demonstrate tractability on massive graphs through execution on a graph with 34 million nodes representing Internet wide router connectivity. PMID:27336059

  4. Fractional crystallization of iron meteorites: Constant versus changing partition coefficients

    NASA Technical Reports Server (NTRS)

    Jones, J. H.

    1994-01-01

    Analyses of magmatic iron meteorites, plotted on LogC(sub i) vs LogC(sub Ni) diagrams, often form linear arrays. Traditionally, this linearity has been ascribed to fractional crystallization under the assumption of constant partition coefficients (i.e., Rayleigh fractionation). Paradoxically, however, partition coefficients in the Fe-Ni-S-P system are decidedly not constant. This contribution provides a rationale for understanding how trends on LogC(sub i) vs LogC(sub Ni) diagrams can be linear, even when partition coefficients are changing rapidly.

  5. Exact partition functions for gauge theories on Rλ3

    NASA Astrophysics Data System (ADS)

    Wallet, Jean-Christophe

    2016-11-01

    The noncommutative space Rλ3, a deformation of R3, supports a 3-parameter family of gauge theory models with gauge-invariant harmonic term, stable vacuum and which are perturbatively finite to all orders. Properties of this family are discussed. The partition function factorizes as an infinite product of reduced partition functions, each one corresponding to the reduced gauge theory on one of the fuzzy spheres entering the decomposition of Rλ3. For a particular sub-family of gauge theories, each reduced partition function is exactly expressible as a ratio of determinants. A relation with integrable 2-D Toda lattice hierarchy is indicated.

  6. Correlation of octanol/water solubility ratios and partition coefficients

    SciTech Connect

    Pinsuwan, S.; Li, A.; Yalkowsky, S.H.

    1995-05-01

    The partition coefficient between octanol and water in an important physicochemical parameter for characterizing the lipophilicity or hydrophobicity of a compound and it is used in many fields, especially in the environmental and pharmaceutical sciences. The octanol/water solubility ratio (S{sub o}/S{sub W}) was found to be highly correlated with the octanol/water partition coefficient (K{sub ow}) of 82 pharmaceutically and environmentally relevant compounds. The solubility ratio gives comparable estimates to that of the group contribution (log P(calcd)) method for estimating the partition coefficient of the compounds used in this study.

  7. Site Partitioning for Redundant Arrays of Distributed Disks

    NASA Technical Reports Server (NTRS)

    Mourad, Antoine N.; Fuchs, W. Kent; Saab, Daniel G.

    1996-01-01

    Redundant arrays of distributed disks (RADD) can be used in a distributed computing system or database system to provide recovery in the presence of disk crashes and temporary and permanent failures of single sites. In this paper, we look at the problem of partitioning the sites of a distributed storage system into redundant arrays in such a way that the communication costs for maintaining the parity information are minimized. We show that the partitioning problem is NP-hard. We then propose and evaluate several heuristic algorithms for finding approximate solutions. Simulation results show that significant reduction in remote parity update costs can be achieved by optimizing the site partitioning scheme.

  8. Rarefied solids

    NASA Technical Reports Server (NTRS)

    Noever, D. A.; Nikora, V. I.

    1994-01-01

    One important limit to creating low density materials is the objects' own weight. As a solid or colloidal matrix becomes more rarefied, gravity acts destructively to compress its suporting skeleton. We describe experimental results and propose a model which matches the low gravity behavior of rarefied or fractal solids. On parabolic airplane flights, we sought to demonstrate a key component of producing higher surface area fractals. Flight paths were selected to give a range of gravity levels: 0.01 g/g(sub 0) (low), 0.16 g(sub 0) (Lunar), 0.33 g/g(sub 0) (Martian), 1 g/g(sub 0) (Earth) and 1.8 g/g(sub 0) (high) (where g(sub 0) = 980 cm/sq s). Results using the model material of hydrophobic silica indicated that stable agglomeration of such tenuous objects can increase markedly in reduced gravity. Optical characterization revealed that fractal dimension changed directly with varying gravity. As measured by fractal dimension, effective surface area and roughness increased by 40% in low gravity. This finding supports the conclusion that relieving internal weight stresses on delicate aggregates can enhance their overall size (by two orders of magnitude) and internal surface area. We conclude that gravitational restructuring limits the overall size and void content of low-density solids. These sparse colloidal regimes may present new and technologically attractive physics, ranging from improved insulators, liquid-like tension in a 'solid' matrix, and characteristically low conductivities for sound and (8 to 14 micrometers wavelength) infrared radiation.

  9. Experimental chlorine partitioning between forsterite, enstatite and aqueous fluid at upper mantle conditions☆

    PubMed Central

    Fabbrizio, Alessandro; Stalder, Roland; Hametner, Kathrin; Günther, Detlef

    2013-01-01

    Cl partition coefficients between forsterite, enstatite and coexisting Cl-bearing aqueous fluids were determined in a series of high pressure and temperature piston cylinder experiments at 2 GPa between 900 and 1300 °C in the system MgO–SiO2–H2O–NaCl–BaO–C±CaCl2±TiO2±Al2O3±F. Diamond aggregates were added to the experimental capsule set-up in order to separate the fluid from the solid residue and enable in situ analysis of the quenched solute by LA-ICP-MS. The chlorine content of forsterite and enstatite was measured by electron microprobe, and the nature of hydrous defects was investigated by infrared spectroscopy. Partition coefficients show similar incompatibility for Cl in forsterite and enstatite, with DClfo/fl = 0.0012 ± 0.0006, DClen/fl = 0.0018 ± 0.0008 and DClfo/en = 1.43 ± 0.71. The values determined for mineral/fluid partitioning are very similar to previously determined values for mineral/melt. Applying the new mineral/fluid partition coefficients to fluids in subduction zones, a contribution between 0.15% and 20% of the total chlorine from the nominally anhydrous minerals is estimated. Infrared spectra of experimental forsterite show absorption bands at 3525 and 3572 cm−1 that are characteristic for hydroxyl point defects associated with trace Ti substitutions, and strongly suggest that the TiO2 content of the system can influence the chlorine and OH incorporation via the stabilization of Ti-clinohumite-like point defects. The water contents for coexisting forsterite and enstatite in some runs were determined using unpolarized IR spectra and calculated water partition coefficients DH2Ofo/en are between 0.01 and 0.5. PMID:25843971

  10. Using measured octanol-air partition coefficients to explain environmental partitioning of organochlorine pesticides.

    PubMed

    Shoeib, Mahiba; Harner, Tom

    2002-05-01

    Octanol-air partition coefficients (Koa) were measured directly for 19 organochlorine (OC) pesticides over the temperature range of 5 to 35 degrees C. Values of log Koa at 25 degrees C ranged over three orders of magnitude, from 7.4 for hexachlorobenzene to 10.1 for 1,1-dichloro-2,2-bis(p-chlorophenyl) ethane. Measured values were compared to values calculated as KowRT/H (where R is the ideal gas constant [8.314 J mol(-1) K(-1)], T is absolute temperature, and H is Henry's law constant) were, in general, larger. Discrepancies of up to three orders of magnitude were observed, highlighting the need for direct measurements of Koa. Plots of Koa versus inverse absolute temperature exhibited a log-linear correlation. Enthalpies of phase transition between octanol and air (deltaHoa) were determined from the temperature slopes and were in the range of 56 to 105 kJ mol(-1) K(-1). Activity coefficients in octanol (gamma(o)) were determined from Koa and reported supercooled liquid vapor pressures (pL(o)), and these were in the range of 0.3 to 12, indicating near-ideal solution behavior. Differences in Koa values for structural isomers of hexachlorocyclohexane were also explored. A Koa-based model was described for predicting the partitioning of OC pesticides to aerosols and used to calculate particulate fractions at 25 and -10 degrees C. The model also agreed well with experimental results for several OC pesticides that were equilibrated with urban aerosols in the laboratory. A log-log regression of the particle-gas partition coefficient versus Koa had a slope near unity, indicating that octanol is a good surrogate for the aerosol organic matter.

  11. Plasmid accumulation reduces life span in Saccharomyces cerevisiae.

    PubMed

    Falcón, Alaric A; Aris, John P

    2003-10-24

    Aging in the yeast Saccharomyces cerevisiae is under the control of multiple pathways. The production and accumulation of extrachromosomal rDNA circles (ERCs) is one pathway that has been proposed to bring about aging in yeast. To test this proposal, we have developed a plasmid-based model system to study the role of DNA episomes in reduction of yeast life span. Recombinant plasmids containing different replication origins, cis-acting partitioning elements, and selectable marker genes were constructed and analyzed for their effects on yeast replicative life span. Plasmids containing the ARS1 replication origin reduce life span to the greatest extent of the plasmids analyzed. This reduction in life span is partially suppressed by a CEN4 centromeric element on ARS1 plasmids. Plasmids containing a replication origin from the endogenous yeast 2 mu circle also reduce life span, but to a lesser extent than ARS1 plasmids. Consistent with this, ARS1 and 2 mu origin plasmids accumulate in approximately 7-generation-old cells, but ARS1/CEN4 plasmids do not. Importantly, ARS1 plasmids accumulate to higher levels in old cells than 2 mu origin plasmids, suggesting a correlation between plasmid accumulation and life span reduction. Reduction in life span is neither an indirect effect of increased ERC levels nor the result of stochastic cessation of growth. The presence of a fully functional 9.1-kb rDNA repeat on plasmids is not required for, and does not augment, reduction in life span. These findings support the view that accumulation of DNA episomes, including episomes such as ERCs, cause cell senescence in yeast.

  12. Heavy metal capture and accumulation in bioretention media.

    PubMed

    Li, Houng; Davis, Allen P

    2008-07-15

    Heavy metal capture and accumulation in bioretention media were investigated through the use of a one-dimensional filtration equation for particulate metals, advection/dispersion/adsorption transport equations for dissolved metals, and sequential extractions. Predicted spatial profiles and partitioning patterns of captured metals were compared to data derived from a bioretention cell in the District of Columbia. Zinc, lead, and copper profiles showed a high surface accumulation, significantly decreasing with the media depth. Surface street particle-enriched areas had the highest heavy metal levels, demonstrating a close relationship between capture of metals and runoff particles. Sequential extractions suggested that most captured metals were of anthropogenic origin. Soluble-exchangeable bound metals from the sequential extraction correlated well with predicted aqueous dissolved metals; the more strongly associated metal fractions correlated with modeled runoff and media particulate metals. A simple risk evaluation indicated thatlead isthe limiting metal in bioretention accumulation. On the basis of information collected in this study, a shallow bioretention cell design is suggested for systems with a focus on metal capture.

  13. Three list scheduling temporal partitioning algorithm of time space characteristic analysis and compare for dynamic reconfigurable computing

    NASA Astrophysics Data System (ADS)

    Chen, Naijin

    2013-03-01

    Level Based Partitioning (LBP) algorithm, Cluster Based Partitioning (CBP) algorithm and Enhance Static List (ESL) temporal partitioning algorithm based on adjacent matrix and adjacent table are designed and implemented in this paper. Also partitioning time and memory occupation based on three algorithms are compared. Experiment results show LBP partitioning algorithm possesses the least partitioning time and better parallel character, as far as memory occupation and partitioning time are concerned, algorithms based on adjacent table have less partitioning time and less space memory occupation.

  14. Partition of actinides and fission products between metal and molten salt phases: Theory, measurement, and application to IFR pyroprocess development

    SciTech Connect

    Ackerman, J.P.; Johnson, T.R.

    1993-10-01

    The chemical basis of Integral Fast Reactor fuel reprocessing (pyroprocessing) is partition of fuel, cladding, and fission product elements between molten LiCl-KCl and either a solid metal phase or a liquid cadmium phase. The partition reactions are described herein, and the thermodynamic basis for predicting distributions of actinides and fission products in the pyroprocess is discussed. The critical role of metal-phase activity coefficients, especially those of rare earth and the transuranic elements, is described. Measured separation factors, which are analogous to equilibrium constants but which involve concentrations rather than activities, are presented. The uses of thermodynamic calculations in process development are described, as are computer codes developed for calculating material flows and phase compositions in pyroprocessing.

  15. Experimental mineral/liquid partition coefficients of the rare earth elements /REE/, Sc and Sr for perovskite, spinel and melilite

    NASA Technical Reports Server (NTRS)

    Nagasawa, H.; Schreiber, H. D.; Morris, R. V.

    1980-01-01

    Experimental determinations of the mineral/liquid partition coefficients of REE (La, Sm, Eu, Gd, Tb, Yb and Lu), Sc and Sr are reported for the minerals perovskite, spinel and melilite in synthetic systems. Perovskite concentrates light REE with respect to the residual liquid but shows no preference for heavy REE. Spinel greatly discriminates against the incorporation of REE, especially light REE, into its crystal structure. The partition of REE into melilite from a silicate liquid is quite dependent upon both the bulk melt and melilite solid-solution (gehlenite and akermanite components) compositions. As such, melilite can be enriched in REE or will reject REE with corresponding strong negative or strong positive Eu anomalies, respectively.

  16. Mobility of Heavy Metals (Pb, Cd, Zn) in the Pampeano and Puelche Aquifers, Argentina: Partition and Retardation Coefficients.

    PubMed

    Jakomin, L M; Marbán, L; Grondona, S; Glok Galli, M; Martínez, D E

    2015-09-01

    The prediction about metals behaviour in soil requires knowledge on their solid-liquid partitioning. Usually it is expressed with an empirical distribution coefficient or Kd, which gives the ratio of the metal concentration in the solid phase to that in the solution. Kd values have been determined for Zn, Pb and Cd from samples representing the two most exploited aquifers in Argentina, Pampeano and Puelche, at three different locations in the province of Buenos Aires. The Pampeano aquifer presented higher Kd values than the Puelche aquifer. Comparing Kd values, different relationships could be observed: (a) Pampeano aquifer: Pb > Zn > Cd, and (b) Puelche aquifer: Pb > Cd > Zn. Kd for Cd seems to be linked to cationic exchange capacity, but solid phases precipitation can be more determining for Pb and Zn.

  17. Influence of digestive morphology on resource partitioning in Amazonian ungulates.

    PubMed

    Bodmer, Richard E

    1991-01-01

    Resource partitioning of diet and habitat use was studied in the entire Amazonian ungulate community of Northeastern Peru, which comprises the red brocket deer (Mazama americana), grey brocket deer (M. gouazoubira), collared peccary (Tayassu tajacu), white-lipped peccary (T. pecari), and lowland tapir (Tapirus terrestris). Each ungulate species partitioned at least one type of resource from every other species. Digestive morphology had a greater influence on resource partitioning of diet than body size. Neither digestive morphology nor body size were related to segregation of habitats. However, species with similar diets partitioned habitats, whereas species with different diets often used the same type of forest. Increases in habitat breadth of ungulates were positively correlated with increases in dietary breadth.

  18. Airflow studies in a forced ventilated chamber with low partitions

    SciTech Connect

    Chow, W.K.; Tsui, K.F.

    1995-12-31

    A climate chamber was used to study experimentally the airflow characteristics in a ventilated space with low partitions. Two types of commonly used air distribution devices were selected for the study--a ceiling diffuser and side grille systems. A total of 16 tests were performed using the two diffusers with partition heights varying up to 1.8 m (5.91 ft) above floor level. From the measured results, the thermal comfort indices were assessed. A stabilization effect of airflow was found when the partition height reached 1.8 m (5.91 ft). Local draft risk was located in the occupied zone. Also, the modified Archimedes number proposed by Jackman (1990) was used to describe the indoor airflow in the absence of a workable design guide for partitioned spaces.

  19. Domain Decomposition By the Advancing-Partition Method

    NASA Technical Reports Server (NTRS)

    Pirzadeh, Shahyar Z.

    2008-01-01

    A new method of domain decomposition has been developed for generating unstructured grids in subdomains either sequentially or using multiple computers in parallel. Domain decomposition is a crucial and challenging step for parallel grid generation. Prior methods are generally based on auxiliary, complex, and computationally intensive operations for defining partition interfaces and usually produce grids of lower quality than those generated in single domains. The new technique, referred to as "Advancing Partition," is based on the Advancing-Front method, which partitions a domain as part of the volume mesh generation in a consistent and "natural" way. The benefits of this approach are: 1) the process of domain decomposition is highly automated, 2) partitioning of domain does not compromise the quality of the generated grids, and 3) the computational overhead for domain decomposition is minimal. The new method has been implemented in NASA's unstructured grid generation code VGRID.

  20. 47 CFR 22.513 - Partitioning and disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MOBILE SERVICES Paging and Radiotelephone Service § 22.513 Partitioning and disaggregation. MEA and EA... unless either an FCC-recognized service area is used (e.g., MEA or EA) or county lines are followed....

  1. 47 CFR 22.221 - Eligibility for partitioned licenses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... geographic area together with the application for the remainder of the MEA or EA filed by the auction winner. (c) If the partitioned authorization is being applied for as a partial assignment of the MEA or...

  2. 47 CFR 22.513 - Partitioning and disaggregation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MOBILE SERVICES Paging and Radiotelephone Service § 22.513 Partitioning and disaggregation. MEA and EA... unless either an FCC-recognized service area is used (e.g., MEA or EA) or county lines are followed....

  3. 47 CFR 22.513 - Partitioning and disaggregation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MOBILE SERVICES Paging and Radiotelephone Service § 22.513 Partitioning and disaggregation. MEA and EA... unless either an FCC-recognized service area is used (e.g., MEA or EA) or county lines are followed....

  4. 47 CFR 22.221 - Eligibility for partitioned licenses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... geographic area together with the application for the remainder of the MEA or EA filed by the auction winner. (c) If the partitioned authorization is being applied for as a partial assignment of the MEA or...

  5. 47 CFR 22.221 - Eligibility for partitioned licenses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... geographic area together with the application for the remainder of the MEA or EA filed by the auction winner. (c) If the partitioned authorization is being applied for as a partial assignment of the MEA or...

  6. 47 CFR 22.513 - Partitioning and disaggregation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MOBILE SERVICES Paging and Radiotelephone Service § 22.513 Partitioning and disaggregation. MEA and EA... unless either an FCC-recognized service area is used (e.g., MEA or EA) or county lines are followed....

  7. 47 CFR 22.513 - Partitioning and disaggregation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MOBILE SERVICES Paging and Radiotelephone Service § 22.513 Partitioning and disaggregation. MEA and EA... unless either an FCC-recognized service area is used (e.g., MEA or EA) or county lines are followed....

  8. 47 CFR 22.221 - Eligibility for partitioned licenses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... geographic area together with the application for the remainder of the MEA or EA filed by the auction winner. (c) If the partitioned authorization is being applied for as a partial assignment of the MEA or...

  9. 47 CFR 22.221 - Eligibility for partitioned licenses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... geographic area together with the application for the remainder of the MEA or EA filed by the auction winner. (c) If the partitioned authorization is being applied for as a partial assignment of the MEA or...

  10. TRACES OF ORIGINAL PARTITIONS AT JUNCTURE OF FRONT ROOM, REAR ...

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

    TRACES OF ORIGINAL PARTITIONS AT JUNCTURE OF FRONT ROOM, REAR ROOM AND HALL, SECOND FLOOR. ALSO SHOWS ORIGINAL STUCCO CORNICE OF FRONT AND REAR ROOMS (LEFT) AND HALL (RIGHT) - Kid-Chandler House, 323 Walnut Street, Philadelphia, Philadelphia County, PA

  11. A Recursive Method for Calculating Certain Partition Functions.

    ERIC Educational Resources Information Center

    Woodrum, Luther; And Others

    1978-01-01

    Describes a simple recursive method for calculating the partition function and average energy of a system consisting of N electrons and L energy levels. Also, presents an efficient APL computer program to utilize the recursion relation. (Author/GA)

  12. VIEW OF EASTERN PARTITION OF FRONT BAY ROOM, FACING SOUTH ...

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

    VIEW OF EASTERN PARTITION OF FRONT BAY ROOM, FACING SOUTH - Cape Canaveral Air Force Station, Launch Complex 34, Operations Support Building, Freedom Road, Southwest of Launch Stand CX-34, Cape Canaveral, Brevard County, FL

  13. VIEW OF EASTERN PARTITION OF FRONT BAY ROOM, FACING NORTHWEST ...

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

    VIEW OF EASTERN PARTITION OF FRONT BAY ROOM, FACING NORTHWEST - Cape Canaveral Air Force Station, Launch Complex 34, Operations Support Building, Freedom Road, Southwest of Launch Stand CX-34, Cape Canaveral, Brevard County, FL

  14. VIEW OF WESTERN PARTITION OF FRONT BAY ROOM, FACING NORTHWEST ...

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

    VIEW OF WESTERN PARTITION OF FRONT BAY ROOM, FACING NORTHWEST - Cape Canaveral Air Force Station, Launch Complex 34, Operations Support Building, Freedom Road, Southwest of Launch Stand CX-34, Cape Canaveral, Brevard County, FL

  15. VIEW OF WESTERN PARTITION OF FRONT BAY ROOM, FACING SOUTH ...

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

    VIEW OF WESTERN PARTITION OF FRONT BAY ROOM, FACING SOUTH - Cape Canaveral Air Force Station, Launch Complex 34, Operations Support Building, Freedom Road, Southwest of Launch Stand CX-34, Cape Canaveral, Brevard County, FL

  16. Distances in spaces of physical models: partition functions versus spectra

    NASA Astrophysics Data System (ADS)

    Cornelissen, Gunther; Kontogeorgis, Aristides

    2017-01-01

    We study the relation between convergence of partition functions (seen as general Dirichlet series) and convergence of spectra and their multiplicities. We describe applications to convergence in physical models, e.g., related to topology change and averaging in cosmology.

  17. 3. INTERIOR VIEW OF PARTITIONS IN DRESSING ROOM; INTERIOR HALLWAY ...

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

    3. INTERIOR VIEW OF PARTITIONS IN DRESSING ROOM; INTERIOR HALLWAY FOR HYDROTHERAPY AREA AT RIGHT - Fort McCoy, Building No. T-1054, South side of South Tenth Avenue, Block 10, Sparta, Monroe County, WI

  18. 5. INTERIOR DETAIL OF 'BATTLESHIP DECK' WALL PARTITION AND CEILING ...

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

    5. INTERIOR DETAIL OF 'BATTLESHIP DECK' WALL PARTITION AND CEILING OF FIRST FLOOR OF 1930 ADDITION TO OFFICE BUILDING - Midwest Steel & Iron Works Company, 25 Larimer Street, Denver, Denver County, CO

  19. Insights into Igneous Geochemistry from Trace Element Partitioning

    NASA Technical Reports Server (NTRS)

    Jones, J. H.; Hanson, B. Z.

    2001-01-01

    Partitioning of trivalent elements into olivine are used to explore basic issues relevant to igneous geochemistry, such as Henry's law. Additional information is contained in the original extended abstract.

  20. Demonstration of Spray Booth Recirculation and Partitioning - Phase II

    DTIC Science & Technology

    1996-01-01

    electrostatic paint spray enclosures, such as the high volume, low pressure ( HVLP ) systems employed at Barstow MCLB, a minimum linear velocity of 100 fpm must be...SUBTITLE 5. FUNDING NUMBERS Demonstration of Spray Booth Recirculation and Partitioning - Phase II N/A 6. AUTHOR(S) D. Proffitt, R.K. Clayton, & J...ANSI Std. Z39-18 298-102 * , 85-1996 Demonstration of Spray Booth Recirculation and Partitioning - Phase II David Proffitt and Russell K. Clayton