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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. Water and nitrogen management effects on biomass accumulation and partitioning in two potato cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biomass accumulation and partitioning into different plant parts is a dynamic process during the plant growing period, which is influenced by crop management and climate factors. Adequate knowledge of biomass partitioning is important to manage the crops to gain maximum partitioning of assimilates i...

  3. Partition function of the elliptic solid-on-solid model as a single determinant

    NASA Astrophysics Data System (ADS)

    Galleas, W.

    2016-07-01

    In this Rapid Communication we express the partition function of the integrable elliptic solid-on-solid model with domain-wall boundary conditions as a single determinant. This representation appears naturally as the solution of a system of functional equations governing the model's partition function.

  4. 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.

  5. 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

  6. 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.

  7. 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. PMID:27586913

  8. PARTITIONING OF TOXIC ORGANIC COMPOUNDS ON MUNICIPAL WASTEWATER TREATMENT PLANT SOLIDS

    EPA Science Inventory

    Fundamental aspects of partitioning of toxic organic compounds on municipal wastewater treatment plant solids have been investigated. Sorption on wastewater solids was not affected by solids-to-liquid ratio. Kinetic data on sorption showed an initial rapid uptake followed by a sl...

  9. Accumulation, distribution and cellular partitioning of mercury in several halophytes of a contaminated salt marsh.

    PubMed

    Castro, Rita; Pereira, Sofia; Lima, Ana; Corticeiro, Sofia; Válega, Mónica; Pereira, Eduarda; Duarte, Armando; Figueira, Etelvina

    2009-09-01

    This work evaluates the role of a plant community in mercury (Hg) stabilization and mobility in a contaminated Portuguese salt marsh. With this aim, the distribution of Hg in below and aboveground tissues, as well as the metal partitioning between cellular fractions (soluble and insoluble) in four different species (Triglochin maritima L., Juncus maritimus Lam, Sarcocornia perennis (Miller) A.J. Scott, and Halimione portulacoides (L.) Aellen) was assessed. Mercury accumulation, translocation and compartmentation between organs and cellular fractions were related to the plant species. Results showed that the degree of Hg absorption and retention was influenced both by environmental parameters and metal translocation/partitioning strategies. Different plant species presented different allocation patterns, with marked differences between monocots (T. maritima and J. maritimus) and dicots (S. perennis, H. portulacoides). Overall, the two monocots, in particular T. maritima showed higher Hg retention in the belowground organs whereas the dicots, particularly S. perennis presented a more pronounced translocation to the aboveground tissues. Considering cellular Hg partitioning, all species showed a higher Hg binding to cell walls and membranes rather than in the soluble fractions. This strategy can be related to the high degree of tolerance observed in the studied species. These results indicate that the composition of salt marsh plant communities can be very important in dictating the Hg mobility within the marsh ecosystem and in the rest of the aquatic system as well as providing important insights to future phytoremediation approaches in Hg contaminated salt marshes. PMID:19595432

  10. Accumulation and partitioning of biomass, nutrients, and trace elements in switchgrass for phytoremediation of municipal biosolids.

    PubMed

    Jeke, Nicholson N; Zvomuya, Francis; Ross, Lisette

    2016-09-01

    In situ phytoremediation of municipal biosolids is a promising alternative to the land spreading and landfilling of biosolids from end-of-life municipal lagoons. Accumulation and partitioning of dry matter, nitrogen (N), phosphorus (P), and trace elements were determined in aboveground biomass (AGB) and belowground biomass (BGB) of switchgrass (Panicum virgatum L.) to determine the harvest stage that maximizes phytoextraction of contaminants from municipal biosolids. Seedlings were transplanted into 15-L plastic pails containing 3.9 kg (dry wt.) biosolids. Biomass yield components and contaminant concentrations were assessed every 14 days for up to 161 days. Logistic model fits to biomass yield data indicated no significant differences in asymptotic yield between AGB and BGB. Switchgrass partitioned significantly more N and P to AGB than to BGB. Maximum uptake occurred 86 days after transplanting (DAT) for N and 102 DAT for P. Harvesting at peak aboveground element accumulation removed 5% of N, 1.6% of P, 0.2% of Zn, 0.05% of Cd, and 0.1% of Cr initially present in the biosolids. These results will contribute toward identification of the harvest stage that will optimize contaminant uptake and enhance in situ phytoremediation of biosolids using switchgrass. PMID:26940512

  11. Equilibrium partitioning of heavy metals in Dutch field soils. 2: Prediction of metal accumulation in earthworms

    SciTech Connect

    Janssen, R.P.T.; Posthuma, L.; Baerselman, R.; Hollander, H.A. Den; Veen, R.P.M. Van; Peijnenburg, W.J.G.M.

    1997-12-01

    To evaluate the adequacy of the equilibrium partitioning concept in predicting metal bioaccumulation, a soil invertebrate species was exposed in 20 Dutch field soils with moderate metal contamination. Earthworms (Eisenia andrei) were kept in the soils for 3 weeks under laboratory conditions. Bioconcentration factors (BCFs) for six metals (Zn, Cu, Pb, Cd, Cr, Ni) and for As were calculated as the ratio of body- and solid-phase metal concentrations. Multivariate statistical analyses suggested that the BCFs for As, Cd, Cu, and Zn are governed by the same soil characteristics that determine equilibrium partition coefficients between the soil solid phase and the pore water. This suggests that uptake of metals is either direct from the pore water or indirect through an uptake route closely related to pore water. Regression equations were derived for predicting BCF values as a function of easily determinable soil characteristics. By means of internal validation it was shown that the equations obtained can be used for predictive purposes within the range of soil properties encountered in the dataset. Due to a lack of data, external validation was possible only in a qualitative sense.

  12. 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

  13. Solid Metal-Liquid Metal Partitioning of Pt, Re, and Os: The Effect of Carbon

    NASA Technical Reports Server (NTRS)

    Chabot, N. L.; Campbell, A. J.; Humayun, M.

    2004-01-01

    If the measured Os isotopic ratios are a signature from the Earth's outer core, understanding them is a unique opportunity to understand more about the Earth's core. The distribution of elements between the Earth's solid inner core and the liquid outer core will depend on their solid metal-liquid metal partition coefficients (D). Solid metal-liquid metal partitioning data are loosely consistent with the needed fractionations between Re-Os and Pt-Os to account for the Os isotopic signature; D(Os) is greater than both D(Re) and D(Pt), and the magnitude of the partition coefficients are similar to those needed [e.g. 7, 8]. The pressure in the core, the composition of the core, and the crystal structure of the solid Fe alloy in the inner core may influence the specific values of the partition coefficients. It may thus be possible to use these sensitivities of the partition coefficients to gain insight into the conditions within the Earth's core. In this abstract, we focus on the compositional influence of C, a potential component of the light element in the Earth's core [9], on the partitioning behaviors of Pt, Re, and Os.

  14. 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).

  15. 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. PMID:24320106

  16. 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.

  17. 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

  18. Partitioning, Persistence, and Accumulation in Digested Sludge of the Topical Antiseptic Triclocarban During Wastewater Treatment

    PubMed Central

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

    2009-01-01

    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 μg/L) and effluent (0.17 ± 0.03 μg/L) was 3,737 ± 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 (2,815 ± 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 catchment area of the plant ultimately is released into the environment by application of municipal

  19. 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

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

    PubMed

    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

  1. 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.

  2. Partitioning gas tracer tests for measurement of water in municipal solid waste.

    PubMed

    Imhoff, Paul T; Jakubowitch, Andrew; Briening, Michele L; Chiu, Pei C

    2003-11-01

    A key component in the operation of almost all bioreactor landfills is the addition of water to maintain optimal moisture conditions. To determine how much water is needed and where to add it, in situ methods are required to measure water within solid waste. Existing technologies often result in measurements of unknown accuracy, because of the variability of solid waste materials and time-dependent changes in packing density, both of which influence most measurement methods. To overcome these problems, a new technology recently developed by hydrologists for measuring water in the vadose zone--the partitioning gas tracer test--was tested. In this technology, the transport behavior of two gas tracers within solid waste is used to measure the fraction of the void space filled with water. One tracer is conservative and does not react with solids or liquids, while a second tracer partitions into the water and is separated from the conservative tracer during transport. This technology was tested in four different solid waste packings and was capable of determining the volumetric water content to within 48% of actual values, with most measurement errors less than 15%. This technology and the factors that affect its applicability to landfills are discussed in this paper. PMID:14649759

  3. 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. PMID:15984790

  4. 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. PMID:27174825

  5. Experimental method development for estimating solid-phase diffusion coefficients and material/air partition coefficients of SVOCs

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoyu; Guo, Zhishi; Roache, Nancy F.

    2014-06-01

    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 estimate parameters Dm and Kma. The SVOCs chosen for study were polychlorinated biphenyl (PCB) congeners, including PCB-52, PCB-66, PCB-101, PCB-110, and PCB-118. The test materials included polypropylene, high density polyethylene, low density polyethylene, polytetrafluoroethylene, polyether ether ketone, glass, stainless steel and concrete. Two 53-L environmental chambers were connected in series, with the relatively stable SVOCs source in the source chamber and the test materials, made as small “buttons”, in the test chamber. Prior to loading the test chamber with the test materials, the test chamber had been dosed with SVOCs for 12 days to “coat” the chamber walls. During the tests, the material buttons were removed from the test chamber at different exposure times to determine the amount of SVOC absorbed by the buttons. SVOC concentrations at the inlet and outlet of the test chamber were also monitored. The data were used to estimate the partition and diffusion coefficients by fitting a sink model to the experimental data. The parameters obtained were employed to predict the accumulation of SVOCs in the sink materials using an existing mass transfer model. The model prediction agreed reasonably well with the experimental data.

  6. Partitioning of heavy metals to suspended solids of the Flint River, Michigan

    SciTech Connect

    McIlroy, L.M.; DePinto, J.V.; Young, T.C.; Martin, S.C.

    1986-01-01

    The sorptive affinity of copper and zinc to suspended river sediments was investigated as a function of pH and adsorbent solids concentration. Water samples from the Flint River in Michigan were centrifuged to yield a composite sediment concentrate used as an adsorbent in experiments determining pH adsorption edges and conditional adsorption isotherms. Copper and zinc exhibited sharp pH adsorption edges at pH values of approximately 4 to 5.5 and 6 to 7, respectively. Both metals exhibited fractional adsorption decreases as total metal in the system increased. Adsorbent concentration increases were shown to cause decreases in measured copper partition coefficients. The indirect relationship between adsorbent concentration and partition coefficient was observed whether the adsorbent was concentrated or diluted without altering bulk solution chemistry. A mathematical formulation that incorporated both the adsorbent mass effects and the separation of sorbed metal into reversible and resistant components satisfactorily described the observations.

  7. Occurrence and solid-liquid partition of sulfonated naphthalene-formaldehyde condensates in the aquatic environment.

    PubMed

    Lange, Frank T; Merklinger, Michael; Wenz, Michael; Brauch, Heinz-J; Lehmann, Markus; Pinter, Istvan

    2005-03-15

    Sulfonated naphthalene-formaldehyde condensates (SNFC) are high production volume chemicals used in a variety of applications, for example, as concrete plasticizers, tanning agents, or dye dispersants. They enter the aquatic environment primarily by the wastewater path. The occurrence and fate of the monomers, which are different isomers of mono- and disulfonated naphthalene, was intensively investigated in previous studies. However, the environmental fate of the persistent higher molecular SNFC is so far widely unknown. This paper describes an ultrasonic extraction under alkaline conditions, followed by ion-pair HPLC with fluorescence detection for the analysis of SNFC oligomers from solid environmental matrixes such as sewage sludge, suspended solids, and river sediments. Limits of quantification of about 0.1 mg kg-1 d.m. were well below the measured concentrations in environmental samples. SNFC were adsorbed to suspended solids and river sediments in three major German rivers (Rhine, Neckar, and Danube) in concentrations typically up to several mg kg(-1) d.m. A total content of about 4 g kg(-1) d.m. was measured in a sewage sludge of a municipal wastewater treatment plant, which receives wastewater from a textile dyeing plant. Furthermore, the first quantitative field data on the partition of SNFC and their monomers between the aqueous phase and solid environmental compartments are presented. Solid-liquid partition coefficients (Kd) of oligomers with a chain-length ranging from three to six naphthalenesulfonate units were derived from the analysis of corresponding wastewater and sewage sludge samples and from suspended solids and river water samples, respectively. Determined Kd values were in the range from 10(2) to 10(4) L kg(-1). PMID:15819205

  8. Integrated transcriptome sequencing and dynamic analysis reveal carbon source partitioning between terpenoid and oil accumulation in developing Lindera glauca fruits

    PubMed Central

    Niu, Jun; Chen, Yinlei; An, Jiyong; Hou, Xinyu; Cai, Jian; Wang, Jia; Zhang, Zhixiang; Lin, Shanzhi

    2015-01-01

    Lindera glauca fruits (LGF) with the abundance of terpenoid and oil has emerged as a novel specific material for industrial and medicinal application in China, but the complex regulatory mechanisms of carbon source partitioning into terpenoid biosynthetic pathway (TBP) and oil biosynthetic pathway (OBP) in developing LGF is still unknown. Here we perform the analysis of contents and compositions of terpenoid and oil from 7 stages of developing LGF to characterize a dramatic difference in temporal accumulative patterns. The resulting 3 crucial samples at 50, 125 and 150 days after flowering (DAF) were selected for comparative deep transcriptome analysis. By Illumina sequencing, the obtained approximately 81 million reads are assembled into 69,160 unigenes, among which 174, 71, 81 and 155 unigenes are implicated in glycolysis, pentose phosphate pathway (PPP), TBP and OBP, respectively. Integrated differential expression profiling and qRT-PCR, we specifically characterize the key enzymes and transcription factors (TFs) involved in regulating carbon allocation ratios for terpenoid or oil accumulation in developing LGF. These results contribute to our understanding of the regulatory mechanisms of carbon source partitioning between terpenoid and oil in developing LGF, and to the improvement of resource utilization and molecular breeding for L. glauca. PMID:26446413

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

    NASA Astrophysics Data System (ADS)

    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.

  10. BIOMASS ACCUMULATION AND PARTITIONING OF EASTERN GAMMAGRASS GROWN UNDER DIFFERENT TEMPERATURE AND CO2 LEVELS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eastern gamagrass has been reported to have one of the highest photosynthetic rates of any C4 species but data on temperature x CO2 interactions are lacking. This study was conducted to determine the potential effects of future increases of atmospheric carbon dioxide on growth, biomass accumulation...

  11. 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

  12. 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

  13. Solid-phase microextraction to determine micropollutant-macromolecule partition coefficients.

    PubMed

    Bridle, Helen L; Heringa, Minne B; Schäfer, Andrea I

    2016-08-01

    Aqueous micropollutants such as estradiol can have a large environmental impact-even at low concentrations. Part of understanding this impact involves determining the extent to which the micropollutants interact with macromolecules in water. In environmental samples, relevant macromolecules to which micropollutants bind are referred to as dissolved organic matter, and the most common examples of these in freshwater and coastal seawater are fulvic and humic acids. In living organisms, the most common macromolecules that affect bioavailability of a drug (or toxin) are proteins such as albumin. Using [2, 4, 6, 7 - (3)H]estradiol as an example compound, this protocol uses solid-phase microextraction and scintillation detection as analytical tools to quantify the amount of radiolabeled micropollutant available in solution. The measured free concentration after exposure to various concentrations of macromolecule (dissolved organic matter or protein) or micropollutant is used to determine the partition coefficient in the case of micropollutant-macromolecule interactions. The calibration and preparatory studies take at least 8 d, and the steps to determine the partition coefficient can be completed within 3 d. The protocol could be modified such that nonlabeled compounds are studied; instead of detection of activity by a liquid scintillation counter (LSC), the compounds can be quantified using gas chromatography-mass spectrometry (GC-MS) or liquid chromatography (LC)-MS(/MS). PMID:27362336

  14. 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. PMID:26956177

  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. An analysis of a new stable partitioned algorithm for FSI problems. Part I: Incompressible flow and elastic solids

    NASA Astrophysics Data System (ADS)

    Banks, J. W.; Henshaw, W. D.; Schwendeman, D. W.

    2014-07-01

    Stable partitioned algorithms for fluid-structure interaction (FSI) problems are developed and analyzed in this two-part paper. Part I describes an algorithm for incompressible flow coupled with compressible elastic solids, while Part II discusses an algorithm for incompressible flow coupled with structural shells. Importantly, these new added-mass partitioned (AMP) schemes are stable and retain full accuracy with no sub-iterations per time step, even in the presence of strong added-mass effects (e.g. for light solids). The numerical approach described here for bulk compressible solids extends the scheme of Banks et al. [1,2] for inviscid compressible flow, and uses Robin (mixed) boundary conditions with the fluid and solid solvers at the interface. The basic AMP Robin conditions, involving a linear combination of velocity and stress, are determined from the outgoing solid characteristic relation normal to the fluid-solid interface combined with the matching conditions on the velocity and traction. Two alternative forms of the AMP conditions are then derived depending on whether the fluid equations are advanced with a fractional-step method or not. The stability and accuracy of the AMP algorithm is evaluated for linearized FSI model problems; the full nonlinear case being left for future consideration. A normal mode analysis is performed to show that the new AMP algorithm is stable for any ratio of the solid and fluid densities, including the case of very light solids when added-mass effects are large. In contrast, it is shown that a traditional partitioned algorithm involving a Dirichlet-Neumann coupling for the same FSI problem is formally unconditionally unstable for any ratio of densities. Exact traveling wave solutions are derived for the FSI model problems, and these solutions are used to verify the stability and accuracy of the corresponding numerical results obtained from the AMP algorithm for the cases of light, medium and heavy solids.

  17. Evaluation of PCDD/F partitioning between vapor and solid phases in MWI flue gases with temperature variation.

    PubMed

    Chi, Kai Hsien; Chang, Moo Been; Chang, Shu Hao

    2006-12-01

    Partitioning of PCDD/Fs (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofuran) between vapor and solid phases in flue gas is affected by several factors including temperature variation. In this study, PCDD/F removal efficiencies achieved with activated carbon injection (ACI) and partitioning of vapor/solid phase PCDD/Fs in flue gases with temperature variation in a municipal waste incinerator (MWI) are evaluated via intensive flue gas sampling. Results indicate that most PCDD/Fs in flue gas downstream of the ACI+bag filter (BF) exist in vapor phase (over 90%) while the removal efficiencies of vapor and solid phase PCDD/Fs are 98.5-99.6% and 99.8-99.9%, respectively. The results of flue gas samplings also indicate that there is optimal operating temperature for PCDD/F removal achieved with ACI. Additionally, a pilot-scale adsorption system (PAS) is constructed in this study to evaluate the PCDD/F partitioning affected by temperature. The results of the PAS experimentation indicate that about 55% and 25% vapor phase PCDD/Fs passing through the filter cake (adsorbent) are transferred to solid phase at 150 and 200 degrees C, respectively. As the temperature is increased to 250 degrees C, filter cake (adsorbent) cannot effectively adsorb vapor phase PCDD/Fs and significant PCDD/Fs are formed via de novo synthesis. PMID:16920255

  18. 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. PMID:25794722

  19. Measuring gas-liquid partition coefficients of aroma compounds by solid phase microextraction, sampling either headspace or liquid.

    PubMed

    Lloyd, Nathan W; Dungan, Stephanie R; Ebeler, Susan E

    2011-08-21

    Hydrophobic compounds are important odorants and nutrients in foods and beverages, as well as environmental contaminants and pharmaceuticals. Factors influencing their partitioning within multi-component systems and/or from the bulk liquid phase to the air are critical for understanding aroma quality and nutrient bioavailability. The equilibrium partitioning of hydrophobic analytes between air and water was analyzed using solid phase microextraction (SPME) in the headspace (HS-SPME) and via direct immersion in the liquid (DI-SPME). The compounds studied serve as models for hydrophobic aroma compounds covering a range of air-water partition coefficients that extends over four orders of magnitude. By varying the total amount of analyte as well as the ratio of vapor to liquid in the closed, static system, the partition coefficient, K(vl), can be determined without the need for an external calibration, eliminating many potential systematic errors. K(vl) determination using DI-SPME in this manner has not been demonstrated before. There was good agreement between results determined by DI-SPME and by HS-SPME over the wide range of partitioning behavior studied. This shows that these two methods are capable of providing accurate, complementary measurements. Precision in K(vl) determination depends strongly on K(vl) magnitude and the ratio of the air and liquid phases. PMID:21727981

  20. 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

    2015-08-01

    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. PMID:26118804

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

    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.

  3. 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

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

    DOE PAGESBeta

    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.

  5. 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 ...

  6. 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. PMID:24167066

  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. Solid-solution partitioning of plutonium in surface waters at the Atomic Weapons Establishment Aldermaston (UK).

    PubMed

    McCubbin, David; Leonard, Kinson S; Greenwood, Richard C; Taylor, Benjamin R

    2004-10-01

    The Atomic Weapons Establishment (AWE) at Aldermaston (Berkshire, UK) has provided and maintained the warheads for the UK's nuclear deterrent for more than 50 years. Whilst the site is radiologically safe, in a few locations the soil contains specific activities of plutonium (Pu) above background arising from a legacy of historic operations. Run-off water (a mixture of rainwater and groundwater) from part of the site is routed into a water management system, and after analysis and radiological assessment, released into local streams. Water and sediment samples have been collected from a number of closely spaced locations within this system to assess the solid-solution partitioning of Pu. Survey work was complemented by batch type desorption experiments to assess redissolution from 'contaminated' sediment into 'uncontaminated' water. The survey data indicate that specific activities of both dissolved and particle bound 239 + 240Pu varied by roughly two orders of magnitude, ranging from approximately 0.7 microBq kg(-1) up to approximately 44 microBq kg(-1), and approximately 1.2 Bq kg(-1) up to approximately 400 Bq kg(-1), respectively, consistent with water originating from different parts of the site. Apparent Kd values varied by an order of magnitude (from 0.7-16 x 10(6)) with an average value of 4 x 10(6). Results from the desorption experiments indicated the extent of redissolution was very small and the derived Kd's corroborated values obtained from the survey work. Kd's given here are compared with other literature values, and are the greatest reported to date. Results are also provided describing the variation in water quality parameters in shallow groundwater samples. Alkalinity values ranged from 120 to 388 mg l(-1) CaCO3 with an average value of 195 mg l(-1) CaCO3. Corresponding values for pH were 6.6-8.3 with an average of 7.5. Over half of the samples were estimated to be supersaturated with respect to calcite. It is suggested that the state of calcite

  9. 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...

  10. Partitioning of Se, As, Sb, Te and Bi between monosulfide solid solution and sulfide melt - Application to magmatic sulfide deposits

    NASA Astrophysics Data System (ADS)

    Helmy, Hassan M.; Ballhaus, Chris; Wohlgemuth-Ueberwasser, Cora; Fonseca, Raúl O. C.; Laurenz, Vera

    2010-11-01

    The chalcogenes (S, Se, Te), semimetals (As, Sb) and the metal Bi are important ligands for noble metals and form a wide range of compositionally diverse minerals with the platinum-group elements (PGE). With the exception of S, few experimental data exist to quantify the behavior of these elements in magmatic sulfide systems. Here we report experimental partition coefficients for Se, Te, As, Sb, and Bi between monosulfide solid solution (mss) and sulfide melt, determined at 950 °C at a range of sulfur fugacities ( fS2) bracketed by the Fe-FeS (metal-troilite) and the Fe 1-×S-S x (mss-sulfur) equilibria. Selenium is shown to partition in mss-saturated sulfide melt as an anion replacing S 2-. Arsenic changes its oxidation state with fS 2 from predominantly anionic speciation at low fS 2, to cationic speciation at high fS 2. The elements Sb, Te, and Bi are so highly incompatible with mss that they can only be present in sulfide melt as cations and/or as neutral metallic species. The partition coefficients derived fall with increasing atomic radius of the element. They also reflect the positions of the respective elements in the Periodic Table: within a group (e.g., As, Sb, Bi) the partition coefficients fall with increasing atomic radius, and within a period the elements of the 15th group are more incompatible with mss than the neighboring elements of the 16th group.

  11. 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.

  12. Study of solid extractants based on malonamides, diglycolamides, and bipyridines for the partitioning of minor actinides from high active wastes

    NASA Astrophysics Data System (ADS)

    Šul'Aková, J.; John, J.; Šebesta, F.

    2006-01-01

    In this work, the performance of the solid extractants with polyacrylonitrile (PAN) binding matrix was studied for the separation of lanthanides and actinides from nitric acid solutions. As extractants, incorporated into the PAN matrix, the N,N‧-dimethyl-N,N‧-dibutyltetradecylmalonamide (DMDBTDMA), N,N‧-dimethyl-N,N‧-dioctyl-hexy-loxyethylmalonamide (DMDOHEMA), N,N,N‧,N‧-tetraoctyldiglycolamide (TODGA), 6,6‧-bis-(5,6-dipentyl-[1,2,4]triazin-3-yl[2,2‧]bipyridinyl (C5BTBP) were used. Weight distribution coefficients Dg of europium and several actinides have been determined for all the composite materials. The kinetics of europium uptake, practical dynamic extraction capacities, and extraction isotherms were also determined. The results obtained revealed that the solid extractants studied are prospective for the partitioning of lanthanides and actinides from liquid radioactive wastes.

  13. Determining octanol-water partition coefficients for extremely hydrophobic chemicals by combining "slow stirring" and solid-phase microextraction.

    PubMed

    Jonker, Michiel T O

    2016-06-01

    Octanol-water partition coefficients (KOW ) are widely used in fate and effects modeling of chemicals. Still, high-quality experimental KOW data are scarce, in particular for very hydrophobic chemicals. This hampers reliable assessments of several fate and effect parameters and the development and validation of new models. One reason for the limited availability of experimental values may relate to the challenging nature of KOW measurements. In the present study, KOW values for 13 polycyclic aromatic hydrocarbons were determined with the gold standard "slow-stirring" method (log KOW 4.6-7.2). These values were then used as reference data for the development of an alternative method for measuring KOW . This approach combined slow stirring and equilibrium sampling of the extremely low aqueous concentrations with polydimethylsiloxane-coated solid-phase microextraction fibers, applying experimentally determined fiber-water partition coefficients. It resulted in KOW values matching the slow-stirring data very well. Therefore, the method was subsequently applied to a series of 17 moderately to extremely hydrophobic petrochemical compounds. The obtained KOW values spanned almost 6 orders of magnitude, with the highest value measuring 10(10.6) . The present study demonstrates that the hydrophobicity domain within which experimental KOW measurements are possible can be extended with the help of solid-phase microextraction and that experimentally determined KOW values can exceed the proposed upper limit of 10(9) . Environ Toxicol Chem 2016;35:1371-1377. © 2015 SETAC. PMID:26550770

  14. Solid-state phase transformations involving solute partitioning: modeling and measuring on the level of individual grains

    SciTech Connect

    Offerman, S.E.; Dijk, N.H. van; Sietsma, J.; Lauridsen, E.M.; Margulies, L.; Grigull, S.; Poulsen, H.F.; Zwaag, S. van der

    2004-09-20

    A simplified grain growth model is presented for the transition from non-overlapping to overlapping diffusion fields of growing neighboring grains during partitioning solid-state transformations in polycrystalline materials. The model is based on unique observations on the austenite decomposition into ferrite and pearlite in medium-carbon steel with the three-dimensional X-ray diffraction microscope. The model explains three types of observed pro-eutectoid ferrite grain growth and austenite grain decomposition, and the indirectly observed carbon exchange between decomposing austenite grains. A direct comparison of the model and the experiment at the level of individual grains shows that the growth of ferrite grains is strongly related to the local carbon concentration and the local density of nuclei. Unusual observations of a non-stationary austenite grain size prior to the transformation, and oscillatory ferrite growth are reported.

  15. Inferences about radionuclide mobility in soils based on the solid/liquid partition coefficients and soil properties.

    PubMed

    Sohlenius, Gustav; Saetre, Peter; Nordén, Sara; Grolander, Sara; Sheppard, Steve

    2013-05-01

    To assist transport modeling in assessments of the radiological impact of a geological repository for radioactive wastes, the mobility of various elements was studied in arable and wetland soils in the Forsmark region, Sweden. Pore water and total element contents were determined for five types of unconsolidated deposits (regolith), spanning a wide range of soil properties with respect to pH and organic matter content. Two soil depths were sampled to capture element mobility in regolith layers affected and unaffected by soil-forming processes. The solid/liquid partition coefficients (K d values) for most elements varied significantly among regolith types. For most elements, the observed variations in K d values could be explained by variations in soil properties. For many elements, mobility increased with decreasing soil pH. The results provide a significant addition of data on radionuclide retention in soils, taking account of soil properties and processes. PMID:23619799

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

    DOE PAGESBeta

    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 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

  17. 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

  18. PARTITIONING OF HEAVY METALS TO SUSPEND SOLIDS OF THE FLINT RIVER, MI

    EPA Science Inventory

    The sorptive affinity of copper and zinc to suspended river sediments was investigated as a function of pH and adsorbent solids concentration. ater samples from the Flint River in Michigan were centrifuged to yield a composite sediment concentrate used as an adsorbent in experime...

  19. Accumulation and partitioning of seven trace metals in mangroves and sediment cores from three estuarine wetlands of Hainan Island, China.

    PubMed

    Qiu, Yao-Wen; Yu, Ke-Fu; Zhang, Gan; Wang, Wen-Xiong

    2011-06-15

    Trace metals in mangrove tissues (leaf, branch, root and fruit) of nine species and sediments of ten cores collected in 2008 from Dongzhai Harbor, Sanya Bay and Yalong Bay, Hainan Island, were analyzed. The average concentrations of Cu, Pb, Zn, Cd, Cr, Hg and As in surface sediments were 14.8, 24.1, 57.9, 0.17, 29.6, 0.08 and 9.7 μg g(-1), whereas those in mangrove tissues were 2.8, 1.4, 8.7, 0.03, 1.1, 0.03, and 0.2 μg g(-1), respectively. Compared to those from other typical mangrove wetlands of the world, the metal levels in Hainan were at low- to median-levels, which is consistent with the fact that Hainan Island is still in low exploitation and its mangroves suffer little impact from human activities. Metal concentrations among different tissues of mangroves were different. In general, Zn and Cu were enriched in fruit, Hg was enriched in leaf, Pb, Cd and Cr were enriched in branch, and As was enriched in root. The cycle of trace metals in mangrove species were estimated. The biota-sediment accumulation factors (BSAFs) followed the sequence of Hg (0.43)>Cu (0.27)>Cd (0.22)>Zn (0.17)>Pb (0.07)>Cr (0.06)>As (0.02). PMID:21501926

  20. 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

  1. Partition of organochlorine concentrations among suspended solids, sediments and brown mussel Perna perna, in tropical bays.

    PubMed

    Galvao, Petrus; Henkelmann, Bernhard; Longo, Renan; Dorneles, Paulo Renato; Torres, João Paulo Machado; Malm, Olaf; Schramm, Karl-Werner

    2014-11-01

    For evaluating the brown mussel Perna perna as a sentinel organism regarding environmental concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), the present study reports original data on the relationship between the concentrations of these chemicals in bottom surface sediments, suspended solids (SS) and concentrations bioaccumulated by this bivalve. Three P. perna cultivation areas, located at three bays in southeastern Brazil were used in this study. The three estuaries are under different degrees of environmental impact. Variations in the OCP and PCB concentrations bioaccumulated by the bivalves tended to be similar to those observed in the sediment, but differed from those found in SS. This latter difference might suggest that the SS trapping apparatuses should have been left in place for approximately 60 days (not only 15 days). This longer period would allow the integration of the environmental variability of the OCP and PCB burden adsorbed to this compartment. Authors encourage future studies to evaluate P. perna exposure to OCPs and PCBs through the evaluation of sediment concentrations. PMID:25113178

  2. 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.

  3. 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.

  4. 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

  5. Simultaneous Flux Measurements of CO2, its Stable Isotope Ratios and Trace Gases Based on Eddy Accumulation Technique for Flux Partitioning

    NASA Astrophysics Data System (ADS)

    Takahashi, Y.; Hirata, R.

    2007-12-01

    For the purpose of determining the CO2 uptake by terrestrial ecosystem, eddy covariance method (EC) is commonly used in the tower-flux measurements. The flux measured by this method is called 'enet ecosystem exchange (NEE)'. NEE has the meaning of difference between two component fluxes, photosynthetic uptake and respiratory release of CO2. Magnitude of both the component fluxes is far larger than NEE. Both the component fluxes have difference in response function against changes in environmental factors, such as temperature and water. Therefore it is important to evaluate the characteristics of variations in the comporent fluxes individually in the future prediction of CO2 uptake by terrestrial ecosystem. Separation of NEE into the componet fluxes is usually done by using an approximate temperature expression of respiratory flux. This approximate expression is based on the assumption that the NEE observed at nighttime equals to the respiratory flux. The photosynthetic uptake of CO2 is defined as difference between the observed NEE and 'respiration' approximated as a temperature-function. Because of its technical simplicity, this approach has provided useful information about climatology of the gross CO2 fluxes. However, the temperature expression of respiratory flux has several limitations in its application. We are now developing a flux-partitioning method using chemical tracers (e.g. stable isotopes of CO2 and carbonyl sulfide) as additional constraints. The flux partitioning using stable isotopes of CO2 is based on the imbalance of net flux of the CO2 isotopes between 'respiration' and 'photosynthesis'. On the other hand, because of this similarity in the control factors for uptake ratio, the net flux of carbonyl sulfide (COS) is regarded as a possible constraint for the functioning of variations in photosynthetic CO2 uptake by terrestrial ecosystem. Field observation of fluxes of those chemical tracers by EC method is difficult due to stringent requirements

  6. Observation of microscopic damage accumulation in brittle solids subjected to dynamic compressive loading

    NASA Astrophysics Data System (ADS)

    Huang, S.; Xia, K.; Zheng, H.

    2013-09-01

    Dynamic failure of brittle materials is a fundamental physical problem that has significantly impacts to many science and engineering disciplines. As the first and the most important step towards the full understanding of this problem, one has to observe dynamic damage accumulation in brittle solids. In this work, we proposed a methodology to do that and demonstrated it by studying the dynamic compressive damage evolution of a granitic rock loaded with a modified split Hopkinson pressure bar system. To ensure consistency of the experimental results, we used cylindrical rock samples fabricated from the same rock core and subjected them to identical incident loading pulse. Using a special soft recovery technique, we stopped the dynamic loading on the samples at different strain levels, ranging from 0.3% to 1.4%. Therefore, we were able to recover intact samples loaded all the way to the post-peak deformation stage. The recovered samples were subsequently examined with X-ray micro-CT scanning machine. Three dimensional microcrack network induced by the dynamic loading was observed and the evolution of microcracks as a function of the dynamic loading strain was obtained.

  7. Trapped Melt in IIIAB Irons: Solid/Liquid Elemental Partitioning During the Fractionation of the IIIAB Magma

    NASA Technical Reports Server (NTRS)

    Wasson, John T.

    1999-01-01

    Group IIIAB, the largest iron-meteorite group, shows compositional trends (including a three-order-of-magnitude It concentration range) indicating that it formed by fractional crystallization of a metallic magma. Because about 200 irons are available, and all degrees of crystallization are well represented, IIIAB offers an excellent set of samples for the study of crystallization at all depths of the asteroidal core. On log-log Ir-Au, and Ir-As diagrams IIIAB forms a broad band; the breadth represents real meteorite-to-meteorite variations, far outside experimental or sampling uncertainties. A successful model must explain the width of this band; I suggest that it mainly resulted from the trapping of parental magma within the crystallizing solid. Because S is essentially insoluble in metal, the abundance of FeS is a measure of the fraction of trapped liquid. The trapped-melt model is supported by the observation that irons having higher S contents plot closer to the inferred composition of the magmatic parental liquid. The lowest S values are found in the irons occupying the left envelope of the IIIAB Ir-Au or Ir-As compositional fields, thus it is this set of irons that should be interpreted as the solid products of a fractionating magma. This simplifies the modeling of the crystallization process and allows inferences regarding the distribution ratios for other elements in the evolved IIIAB system. The large (multiton) Cape York irons show wide variations in their trapped-melt fractions; their compositions seem best understood in terms of a low initial S content of the IIIAB magma, about 20 mg/g. The inferred initial IIIAB distribution coefficient for Ir, 4.6, is much higher than published values based on laboratory studies of low-S systems; I suggest that low-S (and low-P) partition-ratio measurements tend to err in the direction of unity. In IIIAB distribution coefficients for Au, As, and Ni were still < 1 when the most evolved IIIAB irons formed, another

  8. 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

  9. 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. PMID:24992006

  10. 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

  11. 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

  12. 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...

  13. Matrix solid phase dispersion-assisted BCR sequential extraction method for metal partitioning in surface estuarine sediments.

    PubMed

    Martínez-Fernández, Marta; Barciela-Alonso, María Carmen; Moreda-Piñeiro, Antonio; Bermejo-Barrera, Pilar

    2011-01-15

    The BCR (the Community Bureau of Reference) of the European Union sequential extraction scheme for metal partitioning in estuarine sediments has been accelerated by using a matrix solid phase dispersion (MSPD) approach. The MSPD assisted BCR procedure consists of passing the extractants proposed by conventional BCR protocol (0.11 M acetic acid, 0.1M hydroxylammonium chloride and 8.8M hydrogen peroxide plus 1M ammonium acetate) through the dispersed sample packaged inside a disposable syringe. Different silica-, magnesium- and aluminium-based materials were tested as dispersing agents and sea sand was found to offer the best performances. Variables for assisting the three stages of the BCR protocol were optimized, and accurate results were obtained when assisting the first and the third stages (exchangeable and oxidizable fractions, respectively). However, lack of accuracy was observed when assisting the second step (reducible fraction) and this result agrees with most of the assisted BCR procedures for which extracting the reducible fraction is the most troublesome stage. The organic matter oxidation (third stage) was successfully assisted by passing hydrogen peroxide at 50°C through the dispersed sample inside de syringe just before passing ammonium acetate. Therefore, the time-consuming and unsafe conventional organic matter oxidation processes, commonly performed even for microwave/ultrasounds assisted BCR procedures, are totally avoided. Inductively coupled plasma-mass spectrometry (ICP-MS) was used as a selective detector. The target elements were Cd, Co, Cr, Mn, Ni, Sr and Zn (first stage), Cd, Co and Ni (second stage), and Co, Cr, Mn, Ni, Sr and Zn (third stage). Repeatability of the method (n=7) was good, and RSDs values of 9, 10, 10, 8, 8, 3 and 8% was obtained for Cd, Co, Cr, Mn, Ni, Sr and Zn, respectively (first stage); 10, 9 and 9% for Cd, Co and Ni, respectively (second stage); and 6, 2, 3, 4, 7 and 9% Co, Cr, Mn, Ni, Sr and Zn, respectively (third

  14. 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. PMID:25263218

  15. GRACE and AMSR-E-based estimates of winter season solid precipitation accumulation in the Arctic drainage region

    NASA Astrophysics Data System (ADS)

    Seo, Ki-Weon; Ryu, Dongryeol; Kim, Baek-Min; Waliser, Duane E.; Tian, Baijun; Eom, Jooyoung

    2010-10-01

    Solid precipitation plays a major role in controlling the winter hydrological cycle and spring discharge in the Arctic region. However, it has not been well documented due to sharply decreasing numbers of precipitation gauges, gauge measurement biases, as well as limitations of conventional satellite methods in high latitudes. In this study, we document the winter season solid precipitation accumulation in the Arctic region using the latest new satellite measurements from the Gravity Recovery and Climate Experiment (GRACE) and the Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E). GRACE measures the winter total water (mainly from snow water equivalent (SWE)) storage change through gravity changes while AMSR-E measures the winter SWE through passive microwave measurements. The GRACE and AMSR-E measurements are combined with in situ and numerical model estimates of discharge and evapotranspiration to estimate the winter season solid precipitation accumulation in the Arctic region using the water budget equation. These two satellite-based estimates are then compared to the conventional estimates from two global precipitation products, such as the Global Precipitation Climatology Project (GPCP) and Climate Prediction Center's Merged Analysis of Precipitation (CMAP), and three reanalyses, the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis, the European Centre for Medium-Range Weather Forecasts' ERA-Interim, and the Japan Meteorological Agency's Climate Data Assimilation System (JCDAS) reanalysis. The GRACE-based estimate is very close to the GPCP and ERA-Interim estimates. The AMSR-E-based estimate is the most different from the other estimates. This GRACE-based measurement of winter season solid precipitation accumulation can provide a new valuable benchmark to understand the hydrological cycle, to validate and evaluate the model simulation, and to improve data assimilation in the

  16. Liquid accumulation in vibrating vocal fold tissue: A simplified model based on a fluid-saturated porous solid theory

    PubMed Central

    Tao, Chao; Jiang, Jack J.; Czerwonka, Lukasz

    2011-01-01

    The human vocal fold is treated as a continuous, transversally isotropic, porous solid saturated with liquid. A set of mathematical equations, based on the theory of fluid-saturated porous solids, is developed to formulate the vibration of the vocal fold tissue. As the fluid-saturated porous tissue model degenerates to the continuous elastic tissue model when the relative movement of liquid in the porous tissue is ignored, it can be considered a more general description of vocal fold tissue than the continuous, elastic model. Using the fluid-saturated porous tissue model, the vibration of a bunch of one-dimensional fibers in the vocal fold is analytically solved based on the small amplitude assumption. It is found that the vibration of the tissue will lead to the accumulation of excess liquid in the midmembranous vocal fold. The degree of liquid accumulation is positively proportional to the vibratory amplitude and frequency. The correspondence between the liquid distribution predicted by the porous tissue theory and the location of vocal nodules observed in clinical practice, provides theoretical evidence for the liquid accumulation hypothesis of vocal nodule formation (Jiang, Ph. D., dissertation, 1991, University of Iowa). PMID:19660905

  17. Spatial Measurements of Perfusion, Interstitial Fluid Pressure and Liposomes Accumulation in Solid Tumors.

    PubMed

    Stapleton, Shawn; Mirmilshteyn, Daniel; Zheng, Jinzi; Allen, Christine; Jaffray, David A

    2016-01-01

    The heterogeneous intra-tumoral accumulation of liposomes is a critical determinant of their efficacy. Both the chaotic tumor microcirculation and elevated IFP are linked to the heterogeneous intra-tumoral distribution of nanotechnology-based drug delivery systems such as liposomes. In the present study, the relationship between tumor microcirculation, elevated IFP, and accumulation of nanoparticles was investigated through in vivo experimentation. This was accomplished by evaluation of the tumor microcirculation using dynamic contrast enhanced computed tomography (DCE-CT) and measurement of tumor IFP using a novel image-guided robotic needle placement system connected to the micro-CT scanner. The intra-tumoral accumulation of liposomes was determined by CT image-based assessment of a nanoparticle liposomal formulation that stably encapsulate the contrast agent iohexol (CT-liposomes). CT imaging allowed for co-localization of the spatial distribution of tumor hemodynamics, IFP and CT-liposome accumulation in an individual subcutaneous xenograft mouse model of breast cancer. Measurements led to the discovery that perfusion and plasma volume fraction are strong mediators of the intra-tumoral distribution of liposomes. Furthermore, the results suggest that IFP plays an indirect role in mediating liposome distribution through modulating blood flow. PMID:27583578

  18. Occurrence and partition of antibiotics in the liquid and solid phases of swine wastewater from concentrated animal feeding operations in Shandong Province, China.

    PubMed

    Ben, Weiwei; Pan, Xun; Qiang, Zhimin

    2013-04-01

    Swine wastewater represents an important pollution source of antibiotics in the environment; however, regional data about residual antibiotics in swine wastewater are very limited at present. This study investigated the concentrations of three classes of commonly used veterinary antibiotics, including five sulfonamides (SAs), three tetracyclines (TCs) and one macrolide (tiamulin, TIA), in swine wastewater collected from 21 concentrated animal feeding operation (CAFO) sites in Shandong Province, China. Both the liquid and solid (i.e., suspended solids) phases of swine wastewater were analyzed to determine the total concentration of each studied antibiotic. Results indicate that sulfamethazine had the highest median concentration (14.56 μg L(-1)), followed by oxytetracycline (OTC, 8.05 μg L(-1)) and chlortetracycline (CTC, 6.01 μg L(-1)). The maximum detected concentration reached up to 2.02 mg L(-1) (OTC) and the highest detection frequency was 95.1% (CTC). The median concentrations and detection frequencies of antibiotics in winter samples were generally higher than those in summer samples (except CTC). The log Kd values were in the range of 1.31-1.96 for SAs, 2.05-2.33 for TCs, and 1.54-1.58 for TIA in swine wastewater. More TCs (14-28%) preferred to partition in the solid phase than SAs (2-10%) and TIA (5-10%), indicating that the suspended solids of swine wastewater may not be ignored. PMID:23493952

  19. 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

    2015-07-01

    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. PMID:26055751

  20. Gold solubility and partitioning between sulfide liquid, monosulfide solid solution and hydrous mantle melts: Implications for the formation of Au-rich magmas and crust-mantle differentiation

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Audétat, Andreas

    2013-10-01

    The solubility of Au in sulfur-free vs. sulfide-saturated melts and its partitioning behavior between sulfide liquid (SL), monosulfide solid solution (MSS) and hydrous basanite melt at variable Au activities was investigated in a fO2 range of FMQ-2 to FMQ+1.6 at 1200 °C/1.5 GPa using piston cylinder apparatus. Gold solubility in sulfur-free (<100 μg/g S) melt is low (0.6-1.6 μg/g) and increases with fO2 in a manner consistent with Au dissolution as AuO1/2, whereas in sulfide-saturated melts it is high (13.6 ± 1.7 μg/g) and independent of fO2. Variations in the chlorine content of sulfide-saturated melts (0.2-1.2 wt% Cl) had no measurable effect on Au solubility. Gold partition coefficients between sulfide liquid and silicate melt (DAuSL/SM) are very high, ∼10,000 ± 3000, which is at the upper end of values reported in previous studies. Gold partition coefficients between MSS and silicate melt (DAuMSS/SM) are much lower, 60 ± 10, which is at the lower end of previous values. Both DAuSL/SM and DAuMSS/SM are independent of fO2. The new Au partition coefficients were used in conjunction with previously published Cu and Ag partition coefficients to investigate the role of MSS versus SL during partial melting in the source region of primitive potassic magmas and during crust-mantle differentiation. The high Au content of ore deposits associated with potassic magmas has commonly been explained by the dissolution of Au-rich sulfide liquid, either during partial melting in the mantle source or during partial re-melting of sulfide-bearing cumulates at the crust-mantle boundary. We argue that MSS is the dominant sulfide phase in the mantle source region of these magmas, and thus that their high Au content is a consequence of low MSS-silicate melt partition coefficients rather than of sulfide exhaustion or partial re-melting of sulfide-bearing cumulates. Continental crust is depleted in Au, Ag and Cu relative to mantle melts, which was thought to be due to removal of

  1. 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.

  2. 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

  3. Remodeling of extracellular matrix due to solid stress accumulation during tumor growth.

    PubMed

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

    2015-01-01

    Solid stresses emerge as the expanding tumor displaces and deforms the surrounding normal tissue, and also as a result of intratumoral component interplay. Among other things, solid stresses are known to induce extensive extracellular matrix synthesis and reorganization. In this study, we developed a mathematical model of tumor growth that distinguishes the contribution to stress generation by collagenous and non-collagenous tumor structural components, and also investigates collagen fiber remodeling 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 tumor growth and derive the mechanical properties of the tumor. Subsequently, we fitted the mathematical model to experimental data to determine values of the model parameters. According to the model, intratumoral solid stress is compressive, whereas extratumoral stress in the tumor vicinity is compressive in the radial direction and tensile in the periphery. Furthermore, collagen fibers engaged in stress generation only in the peritumoral region, and not in the interior where they were slackened due to the compressive stress state. Peritumoral fibers were driven away from the radial direction, tended to realign tangent to the tumor-host interface, and were also significantly stretched by tensile circumferential stresses. By means of this remodeling, the model predicts that the tumor is enveloped by a progressively thickening capsule of collagen fibers. This prediction is consistent with long-standing observations of tumor encapsulation and histologic sections that we performed, and it further corroborates the expansive growth hypothesis for the capsule formation. PMID:26194953

  4. 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.

  5. Optimization of erythritol and glycerol accumulation in conidia of Beauveria bassiana by solid-state fermentation, using response surface methodology.

    PubMed

    Tarocco, Federico; Lecuona, Roberto E; Couto, Alicia S; Arcas, Jorge A

    2005-09-01

    Entomopathogenic fungi are widely produced for use as mycoinsecticides. Therefore, improvement of the shelf life of fungal propagules under good and adverse conditions should be a pre-requisite of their production. In order to improve conidial physiology as well as mycoinsecticide efficiency, culture conditions may be varied. The Doehlert design was used to generate response surfaces with an estimation of the parameters of the quadratic model allowing the study of three different factors at a different number of levels. This experimental design was applied to optimize water activity (aw), pH, and fermentation time for Beauveria bassiana conidial production and accumulation of polyols in solid-state fermentation. Thus, it was possible to identify the region in the experimental range in which the optimum values of these parameters were simultaneously achieved. Maximal conidia production was achieved at pH 5-6 and aw=0.999. Under these conditions, polyol accumulation was 3 mg erythritol/g conidia and 29.6 mg glycerol/g conidia. However, maximal polyol accumulation was achieved at pH 4.5 and aw 0.950; erythritol production increased 33-fold and glycerol production 4.5-fold. Under these conditions conidia production was 1,000 times lower. The possibilities of increasing the quality of the biocontrol agent without neglecting yield are discussed. PMID:15731900

  6. 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.

  7. 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

  8. 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....

  9. Spatial distribution and accumulation of radicals arising in organic solids under the action of glow discharge

    NASA Astrophysics Data System (ADS)

    Raitsimring, A. M.; Kurshev, V. V.

    1994-12-01

    The method, based on analyzing the dipolar broadening of EPR spectra was applied for investigation of the spatial distribution of radicals generated by high-frequency glow discharge in organic molecular crystals (powders of malonic and dimethylmalonic acids) and glassy isopropanol contained electron scavenger. It was shown that in the first case the radical distribution does not depend on time of discharge. The radicals are generated in layer of size ˜.05-0.1 μm at a concentration of ˜2 10 20 cm -3. For the second case the distribution function was changed in the course of plasma treatment and the depth of radical generation was varied from 0.25 to 1.5 μm during the discharge action. Contribution of the various mechanisms of radical formation were evaluated and it was shown that ionic mechanism predominated. A kinetic model is proposed to describe both the radical accumulation and evolution of spatial distribution function in plasmolysis. The use of the model, method and obtained data for general and practical applications is discussed.

  10. 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.

  11. 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

  12. Partitioning of trace elements and metals between quasi-ultrafine, accumulation and coarse aerosols in indoor and outdoor air in schools

    NASA Astrophysics Data System (ADS)

    Viana, M.; Rivas, I.; Querol, X.; Alastuey, A.; Álvarez-Pedrerol, M.; Bouso, L.; Sioutas, C.; Sunyer, J.

    2015-04-01

    Particle size distribution patterns of trace elements and metals across three size fractions (<0.25 μm, quasi-ultrafine particles, q-UF; 0.25-2.5 μm, accumulation particles; 2.5-10 μm, coarse particles) were analysed in indoor and outdoor air at 39 primary schools across Barcelona (Spain). Special attention was paid to emission sources in each particle size range. Results evidenced the presence in q-UF particles of high proportions of elements typically found in coarse PM (Ca, Al, Fe, Mn or Na), as well as several potentially health-hazardous metals (Mn, Cu, Sn, V, Pb). Modal shifts (e.g., from accumulation to coarse or q-UF particles) were detected when particles infiltrated indoors, mainly for secondary inorganic aerosols. Our results indicate that the location of schools in heavily trafficked areas increases the abundance of q-UF particles, which infiltrate indoors quite effectively, and thus may impact children exposure to these health-hazardous particles.

  13. The fate of steroid estrogens: partitioning during wastewater treatment and onto river sediments.

    PubMed

    Gomes, Rachel L; Scrimshaw, Mark D; Cartmell, Elise; Lester, John N

    2011-04-01

    The partitioning of steroid estrogens in wastewater treatment and receiving waters is likely to influence their discharge to, and persistence in, the environment. This study investigated the partitioning behaviour of steroid estrogens in both laboratory and field studies. Partitioning onto activated sludge from laboratory-scale Husmann units was rapid with equilibrium achieved after 1 h. Sorption isotherms and Kd values decreased in the order 17α-ethinyl estradiol>17α-estradiol>estrone>estriol without a sorption limit being achieved (1/n>1). Samples from a wastewater treatment works indicated no accumulation of steroid estrogens in solids from primary or secondary biological treatment, however, a range of steroid estrogens were identified in sediment samples from the River Thames. This would indicate that partitioning in the environment may play a role in the long-term fate of estrogens, with an indication that they will be recalcitrant in anaerobic conditions. PMID:20556648

  14. 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.

  15. 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 ...

  16. 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

  17. Investigation of Particle Accumulation, Chemosensitivity and Thermosensitivity for Effective Solid Tumor Therapy Using Thermosensitive Liposomes and Hyperthermia

    PubMed Central

    Lokerse, Wouter J.M.; Bolkestein, Michiel; ten Hagen, Timo L.M.; de Jong, Marion; Eggermont, Alexander M.M.; Grüll, Holger; Koning, Gerben A.

    2016-01-01

    Doxorubicin (Dox) loaded thermosensitive liposomes (TSLs) have shown promising results for hyperthermia-induced local drug delivery to solid tumors. Typically, the tumor is heated to hyperthermic temperatures (41-42 °C), which induced intravascular drug release from TSLs within the tumor tissue leading to high local drug concentrations (1-step delivery protocol). Next to providing a trigger for drug release, hyperthermia (HT) has been shown to be cytotoxic to tumor tissue, to enhance chemosensitivity and to increase particle extravasation from the vasculature into the tumor interstitial space. The latter can be exploited for a 2-step delivery protocol, where HT is applied prior to i.v. TSL injection to enhance tumor uptake, and after 4 hours waiting time for a second time to induce drug release. In this study, we compare the 1- and 2-step delivery protocols and investigate which factors are of importance for a therapeutic response. In murine B16 melanoma and BFS-1 sarcoma cell lines, HT induced an enhanced Dox uptake in 2D and 3D models, resulting in enhanced chemosensitivity. In vivo, therapeutic efficacy studies were performed for both tumor models, showing a therapeutic response for only the 1-step delivery protocol. SPECT/CT imaging allowed quantification of the liposomal accumulation in both tumor models at physiological temperatures and after a HT treatment. A simple two compartment model was used to derive respective rates for liposomal uptake, washout and retention, showing that the B16 model has a twofold higher liposomal uptake compared to the BFS-1 tumor. HT increases uptake and retention of liposomes in both tumors models by the same factor of 1.66 maintaining the absolute differences between the two models. Histology showed that HT induced apoptosis, blood vessel integrity and interstitial structures are important factors for TSL accumulation in the investigated tumor types. However, modeling data indicated that the intraliposomal Dox fraction did not

  18. Effects of pressure and composition on Pt-Re-Os partitioning behavior between solid and liquid metal in the Fe-Ni-S system: Implication for Os isotopic anomalies in plume-derived lavas

    NASA Astrophysics Data System (ADS)

    Hayashi, H.; Ohtani, E.; Terasaki, H.; Ito, Y.

    2008-12-01

    Coupled 186Os/188Os and 187Os/188Os enrichments of plume-derived lavas have been suggested to reflect material contribution from the outer core (e.g., Brandon, 1998). This geochemical hypothesis is based on an assumption that the outer core shows coupled enrichments in 186Os/ 188Os and 187Os/ 188Os ratio, reflecting the decay of 190Pt and 187Re to 186Os and 187Os, respectively. In order to examine this hypothesis, partitioning experiments of Pt-Re-Os between solid metal and liquid metal were performed using an MA-8 Kawai-type multi-anvil apparatus at 5-20 GPa and 1250-1400C. Starting materials of Fe metal, Ni (7 wt.%) metal and FeS (5 wt.% S in the bulk) were doped with 3 wt.% of Pt, Re and Os metals. Concentrations of all elements were determined using JXA-8800M electron probe microanalyzer with wave-dispersive spectrometry. Measured partition coefficients of Pt, Re and Os increase with increasing sulfur content and almost constant with increasing pressure. Therefore, the effect of liquid composition on the partitioning behavior of highly siderophile elements is much more significant compared to the effect of pressure and temperature. On the basis of the present experimental results, it is unlikely to generate the required Pt-Re-Os fractionation during inner core crystallization assuming that the light element in the Earth"fs core is sulfur only.

  19. 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-...

  20. Solid-solution partitioning of organic matter in soils as influenced by an increase in pH or Ca concentration.

    PubMed

    Oste, L A; Temminghoff, E J M; van Riemsdijk, W H

    2002-01-15

    Organic matter is an important component of soil with regard to the binding of contaminants. Hence, the partitioning of organic matter influences the partitioning of soil contaminants. The partitioning of organic matter is, among other factors, influenced by the ionic composition and ionic strength of the soil solution. This study focuses on the behavior of organic matter after a change in the ionic composition of the soil solution, particularly in Ca concentration and pH. Different amounts of Ca(NO3)2 and NaOH were added to soil suspensions. The dissolved organic carbon (DOC) concentration increased with increasing pH (addition of NaOH), whereas an increase in Ca (addition of Ca(NO3)2) had the opposite effect. A stronger increase in DOC was observed if a single dose of NaOH was added, compared to a gradual addition of the same amount of NaOH. Cation binding by organic matter in the supernatant was calculated using the NICA-Donnan model. The log DOC concentration appeared to be correlated to the Donnan potential, calculated under the assumption that all DOC equals humic acid. This correlation was found for all eight neutral to acidic soils used in this study, although the slopes and elevations of the regression lines varied. The slope varied by a factor of 2 and the elevation appeared to be strongly influenced by the DOC concentration in the untreated soils, which is related to the total organic matter in the soil. Finally, we predicted the Donnan potential on the basis of an extraction of untreated soil with 0.03 M NaNO3, and the total additions of Ca(NO3)2 and NaOH. Comparison of these predictions with speciation calculations in solution showed a good correlation, indicating that a combination of one batch experiment and the presented calculation procedure can provide good estimations of DOC concentrations after addition of chemicals. PMID:11831217

  1. 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. PMID:23286990

  2. 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.

  3. 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

  4. Neutron relative biological effectiveness for solid cancer incidence in the Japanese A-bomb survivors: an analysis considering the degree of independent effects from γ-ray and neutron absorbed doses with hierarchical partitioning.

    PubMed

    Walsh, Linda

    2013-03-01

    It has generally been assumed that the neutron and γ-ray absorbed doses in the data from the life span study (LSS) of the Japanese A-bomb survivors are too highly correlated for an independent separation of the all solid cancer risks due to neutrons and due to γ-rays. However, with the release of the most recent data for all solid cancer incidence and the increased statistical power over previous datasets, it is instructive to consider alternatives to the usual approaches. Simple excess relative risk (ERR) models for radiation-induced solid cancer incidence fitted to the LSS epidemiological data have been applied with neutron and γ-ray absorbed doses as separate explanatory covariables. A simple evaluation of the degree of independent effects from γ-ray and neutron absorbed doses on the all solid cancer risk with the hierarchical partitioning (HP) technique is presented here. The degree of multi-collinearity between the γ-ray and neutron absorbed doses has also been considered. The results show that, whereas the partial correlation between the neutron and γ-ray colon absorbed doses may be considered to be high at 0.74, this value is just below the level beyond which remedial action, such as adding the doses together, is usually recommended. The resulting variance inflation factor is 2.2. Applying HP indicates that just under half of the drop in deviance resulting from adding the γ-ray and neutron absorbed doses to the baseline risk model comes from the joint effects of the neutrons and γ-rays-leaving a substantial proportion of this deviance drop accounted for by individual effects of the neutrons and γ-rays. The average ERR/Gy γ-ray absorbed dose and the ERR/Gy neutron absorbed dose that have been obtained here directly for the first time, agree well with previous indirect estimates. The average relative biological effectiveness (RBE) of neutrons relative to γ-rays, calculated directly from fit parameters to the all solid cancer ERR model with both

  5. A new type of isotherm for zinc liquid-solid partitioning on δ-MnO2, γ-MnOOH and manganite in seawater

    NASA Astrophysics Data System (ADS)

    Pan, Gang; Zhang, Zhengbin; Liu, Liansheng

    1987-03-01

    This article deals with the interaction of zinc with δ-MnO2, γ-MnOOH and manganite existing in natural water systems. The mechanism of the reaction has been studied in detail. From the fact that the “ratio of ion exchange(%)-pH” graph is an “S shaped” curve, it is possible to deduce that the chemical reaction is of the nature of cation exchange. And since the pH range of ion exchange=4, it is possible to further deduce that the reaction can be explained by the mechanism of monovalence cation exchange. The main result of this article is the discovery of a new type of isotherm which has not been mentioned in previous literature here and abroad. This isotherm cannot be represented by any presently available adsorption isotherm equations in marine chemistry. The characteristics of this new type of isotherm are as follows: the isotherm has two “knees” and three “plateaus”, the heights of these three “plateaus” are in the ratio 1:2:3. In order to explain theoretically our new isotherm, this article suggests the application of the principle of interfacial stepwise ion exchange for liquid-solid distribution of minor elements on suspended particulate matter. The corresponding isotherm equation was derived from this theory. The results obtained in this article will be of theoretical guiding significance in the study of the marine geochemistry of zinc.

  6. 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...

  7. 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.

  8. Continuous partition lattice

    PubMed Central

    Björner, Anders

    1987-01-01

    A continuous analogue to the partition lattices is presented. This is the metric completion of the direct limit of a system of embeddings of the finite partition lattices. The construction is analogous to von Neumann's construction of a continuous geometry over a field F from the finite-dimensional projective geometries over F. PMID:16593874

  9. 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.

  10. 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.

  11. Fuzzy Partition Models for Fitting a Set of Partitions.

    ERIC Educational Resources Information Center

    Gordon, A. D.; Vichi, M.

    2001-01-01

    Describes methods for fitting a fuzzy consensus partition to a set of partitions of the same set of objects. Describes and illustrates three models defining median partitions and compares these methods to an alternative approach to obtaining a consensus fuzzy partition. Discusses interesting differences in the results. (SLD)

  12. Partitioning and parallel radiosity

    NASA Astrophysics Data System (ADS)

    Merzouk, S.; Winkler, C.; Paul, J. C.

    1996-03-01

    This paper proposes a theoretical framework, based on domain subdivision for parallel radiosity. Moreover, three various implementation approaches, taking advantage of partitioning algorithms and global shared memory architecture, are presented.

  13. Comparison of an acetonitrile extraction/partitioning and "dispersive solid-phase extraction" method with classical multi-residue methods for the extraction of herbicide residues in barley samples.

    PubMed

    Díez, C; Traag, W A; Zommer, P; Marinero, P; Atienza, J

    2006-10-27

    An acetonitrile/partitioning extraction and "dispersive solid-phase extraction (SPE)" method that provides high quality results with a minimum number of steps and a low solvent and glassware consumption was published in 2003. This method, suitable for the analysis of multiple classes of pesticide residues in foods, has been given an acronymic name, QuEChERS, that reflects its major advantages (quick, easy, cheap, effective, rugged, safe). In this work, QuEChERS method, which was originally created for vegetable samples with a high amount of water, was modified to optimise the extraction of a wide range of herbicides in barley. Then, it was compared with known conventional multi-residue extraction procedures such as the Luke method, which was simplified and shortened by eliminating the Florisil clean-up (mini Luke) and the ethyl acetate extraction, which involves a subsequent clean-up by gel permeation chromatography (GPC) and which is the official extraction method used by some of European authorities. Finally, a simple acetone extraction was carried out to check the differences with the other three methods. Extracts were analysed by gas chromatography-time-of-flight mass spectrometry (GC-TOF/MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Mini Luke was significantly more effective for the extraction of non-polar and medium-polar compounds, but the best recoveries for polar compounds were achieved by QuEChERS and ethyl acetate methods. QuEChERS was the only method that provided an overall recovery value of 60-70% for non-, medium- and polar compounds, with some exceptions due to co-eluted matrix interferences. Clean-up by dispersive SPE was effective and did not differ so much with ethyl acetate extracts considering that QuEChERS clean-up step is much easier and less time-consuming. As a conclusion, it resulted to be the most universal extraction method by providing a well-defined phase separation without dilution and achieving acceptable

  14. PARTITIONING OF ORGANIC COMPOUNDS IN OCTANOL-WATER SYSTEMS

    EPA Science Inventory

    When plots of the log of the octanol-water partition coefficients vs log of water solubilities of a wide variety of liquid and solid solutes are modified by converting the solid solubilities to the estimated solubilities of the corresponding supercooled liquids, the differences b...

  15. 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...

  16. 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.

  17. 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.

  18. Partition density functional theory

    NASA Astrophysics Data System (ADS)

    Nafziger, Jonathan

    Partition density functional theory (PDFT) is a method for dividing a molecular electronic structure calculation into fragment calculations. The molecular density and energy corresponding to Kohn Sham density-functional theory (KS-DFT) may be exactly recovered from these fragments. Each fragment acts as an isolated system except for the influence of a global one-body 'partition' potential which deforms the fragment densities. In this work, the developments of PDFT are put into the context of other fragment-based density functional methods. We developed three numerical implementations of PDFT: One within the NWChem computational chemistry package using basis sets, and the other two developed from scratch using real-space grids. It is shown that all three of these programs can exactly reproduce a KS-DFT calculation via fragment calculations. The first of our in-house codes handles non-interacting electrons in arbitrary one-dimensional potentials with any number of fragments. This code is used to explore how the exact partition potential changes for different partitionings of the same system and also to study features which determine which systems yield non-integer PDFT occupations and which systems are locked into integer PDFT occupations. The second in-house code, CADMium, performs real-space calculations of diatomic molecules. Features of the exact partition potential are studied for a variety of cases and an analytical formula determining singularities in the partition potential is derived. We introduce an approximation for the non-additive kinetic energy and show how this quantity can be computed exactly. Finally a PDFT functional is developed to address the issues of static correlation and delocalization errors in approximations within DFT. The functional is applied to the dissociation of H2 + and H2.

  19. 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.

  20. Cumulants of partitions

    NASA Astrophysics Data System (ADS)

    Weiss, Christoph; Block, Martin; Holthaus, Martin; Schmieder, Gerald

    2003-02-01

    We utilize the formal equivalence between the number-partitioning problem and a harmonically trapped ideal Bose gas within the microcanonical ensemble for characterizing the probability distribution which governs the number of addends occurring in an unrestricted partition of a natural number n. By deriving accurate asymptotic formulae for its coefficients of skewness and excess, it is shown that this distribution remains non-Gaussian even when n is made arbitrarily large. Both skewness and excess vary substantially before settling to their constant-limiting values for n > 1010.

  1. 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.

  2. 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.

  3. New Aperture Partitioning Element

    NASA Astrophysics Data System (ADS)

    Griffin, S.; Calef, B.; Williams, S.

    Postprocessing in an optical system can be aided by adding an optical element to partition the pupil into a number of segments. When imaging through the atmosphere, the recorded data are blurred by temperature-induced variations in the index of refraction along the line of sight. Using speckle imaging techniques developed in the astronomy community, this blurring can be corrected to some degree. The effectiveness of these techniques is diminished by redundant baselines in the pupil. Partitioning the pupil reduces the degree of baseline redundancy, and therefore improves the quality of images that can be obtained from the system. It is possible to implement the described approach on an optical system with a segmented primary mirror, but not very practical. This is because most optical systems do not have segmented primary mirrors, and those that do have relatively low bandwidth positioning of segments due to their large mass and inertia. It is much more practical to position an active aperture partitioning element at an aft optics pupil of the optical system. This paper describes the design, implementation and testing of a new aperture partitioning element that is completely reflective and reconfigurable. The device uses four independent, annular segments that can be positioned with a high degree of accuracy without impacting optical wavefront of each segment. This mirror has been produced and is currently deployed and working on the 3.6 m telescope.

  4. 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.

  5. 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.

  6. Comparison of pressurized liquid extraction and matrix solid-phase dispersion for the measurement of semivolatile organic compound accumulation in tadpoles.

    PubMed

    Stanley, Kerri; Simonich, Staci Massey; Bradford, David; Davidson, Carlos; Tallent-Halsell, Nita

    2009-10-01

    Analytical methods capable of trace measurement of semivolatile organic compounds (SOCs) are necessary to assess the exposure of tadpoles to contaminants as a result of long-range and regional atmospheric transport and deposition. The present study compares the results of two analytical methods, one using pressurized liquid extraction (PLE) and the other using matrix solid-phase dispersion (MSPD), for the trace measurement of more than 70 SOCs in tadpole tissue, including current-use pesticides. The MSPD method resulted in improved SOC recoveries and precision compared to the PLE method. The MSPD method also required less time, consumed less solvent, and resulted in the measurement of a greater number of SOCs than the PLE method. PMID:19432502

  7. 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.

  8. 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.

  9. 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. PMID:27070857

  10. 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 ...

  11. Metal partitioning and toxicity in sewage sludge

    SciTech Connect

    Carlson-Ekvall, C.E.A.; Morrison, G.M.

    1995-12-31

    Over 20 years of research has failed to provide an unequivocal correlation between chemically extracted metals in sewage sludge applied to agricultural soil and either metal toxicity to soil organisms or crop uptake. Partitioning of metals between phases and species can provide a better estimation of mobility and potential bioavailability. Partition coefficients, K{sub D} for Cd, Cu, Pb and Zn in a sludge/water solution were determined considering the sludge/water solution as a three-phase system (particulate, colloidal and electrochemically available) over a range of pH values, ionic strengths, contact times and sludge/water ratios and compared with the KD values for sludge/water solution as a two-phase system (aqueous phase and particulate phase). Partitioning results were interpreted in terms of metal mobility from sludge to colloids and in terms of potential bioavailability from colloids to electrochemically available. The results show that both mobility and potential bioavailability are high for Zn, while Cu partitions into the mobile colloidal phase which is relatively non-bioavailable. Lead is almost completely bound to the solid phase, and is neither mobile nor bioavailable. A comparison between K, values and toxicity shows that Zn in sludge is more toxic than can be accounted for in the aqueous phase, which can be due to synergistic effects between sludge organics and Zn. Copper demonstrates clear synergism which can be attributed to the formation of lipid-soluble Cu complexes with known sludge components such as LAS, caffeine, myristic acid and nonylphenol.

  12. 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.

  13. Flux Partitioning by Isotopic Eddy Covariance

    NASA Astrophysics Data System (ADS)

    Wehr, R.; Munger, J. W.; Nelson, D. D.; McManus, J. B.; Zahniser, M. S.; Wofsy, S. C.; Saleska, S. R.

    2011-12-01

    Net ecosystem-atmosphere exchange of CO2 is routinely measured by eddy covariance at sites around the world, but studies of ecosystem processes are more interested in the gross photosynthetic and respiratory fluxes that comprise the net flux. The standard method of partitioning the net flux into these components has been to extrapolate nighttime respiration into daytime based on a relationship between nighttime respiration, temperature, and sometimes moisture. However, such relationships generally account for only a small portion of the variation in nighttime respiration, and the assumption that they can predict respiration throughout the day is dubious. A promising alternate method, known as isotopic flux partitioning, works by identifying the stable isotopic signatures of photosynthesis and respiration in the CO2 flux. We have used this method to partition the net flux at Harvard Forest, MA, based on eddy covariance measurements of the net 12CO2 and 13CO2 fluxes (as well as measurements of the sensible and latent heat fluxes and other meteorological variables). The CO2 isotopologues were measured at 4 Hz by an Aerodyne quantum cascade laser spectrometer with a δ13C precision of 0.4 % in 0.25 sec and 0.02 % in 100 sec. In the absence of such high-frequency, high-precision isotopic measurements, past attempts at isotopic flux partitioning have combined isotopic flask measurements with high-frequency (total) CO2 measurements to estimate the isoflux (the EC/flask approach). Others have used a conditional flask sampling approach called hyperbolic relaxed eddy accumulation (HREA). We 'sampled' our data according to each of these approaches, for comparison, and found disagreement in the calculated fluxes of ~10% for the EC/flask approach, and ~30% for HREA, at midday. To our knowledge, this is the first example of flux partitioning by isotopic eddy covariance. Wider use of this method, enabled by a new generation of laser spectrometers, promises to open a new window

  14. Quantum field theory of partitions

    SciTech Connect

    Bender, C.M.; Brody, D.C.; Meister, B.K.

    1999-07-01

    Given a sequence of numbers {l_brace}a{sub n}{r_brace}, it is always possible to find a set of Feynman rules that reproduce that sequence. For the special case of the partitions of the integers, the appropriate Feynman rules give rise to graphs that represent the partitions in a clear pictorial fashion. These Feynman rules can be used to generate the Bell numbers B(n) and the Stirling numbers S(n,k) that are associated with the partitions of the integers. {copyright} {ital 1999 American Institute of Physics.}

  15. Probabilistic framework for network partition

    NASA Astrophysics Data System (ADS)

    Li, Tiejun; Liu, Jian; E, Weinan

    2009-08-01

    Given a large and complex network, we would like to find the partition of this network into a small number of clusters. This question has been addressed in many different ways. In a previous paper, we proposed a deterministic framework for an optimal partition of a network as well as the associated algorithms. In this paper, we extend this framework to a probabilistic setting, in which each node has a certain probability of belonging to a certain cluster. Two classes of numerical algorithms for such a probabilistic network partition are presented and tested. Application to three representative examples is discussed.

  16. 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. PMID:27209800

  17. 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.

  18. Graph Partitioning and Sequencing Software

    Energy Science and Technology Software Center (ESTSC)

    1995-09-19

    Graph partitioning is a fundemental problem in many scientific contexts. CHACO2.0 is a software package designed to partition and sequence graphs. CHACO2.0 allows for recursive application of several methods for finding small edge separators in weighted graphs. These methods include inertial, spectral, Kernighan Lin and multilevel methods in addition to several simpler strategies. Each of these approaches can be used to partition the graph into two, four, or eight pieces at each level of recursion.more » In addition, the Kernighan Lin method can be used to improve partitions generated by any of the other algorithms. CHACO2.0 can also be used to address various graph sequencing problems, with applications to scientific computing, database design, gene sequencing and other problems.« less

  19. 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.

  20. 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.

  1. 40 CFR 262.34 - Accumulation time.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Accumulation time. 262.34 Section 262.34 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.34 Accumulation time. (a) Except as provided in paragraphs (d),...

  2. Update on the Argonne positron accumulator ring

    SciTech Connect

    Borland, M.

    1993-07-01

    The injector for the Advanced Photon Source incorporates a 450-MeV positron accumulator ring (PAR) to decrease the filling time with the 2-Hz synchrotron. In addition to accumulating positrons from the linac, the PAR damps the beam and reduces the bunch length. The PAR lattice has been redesigned to use zero-gradient dipoles, while retaining essentially the same damping partition. Extensive simulations have been performed to set tolerances that will give high capture efficiency, in spite of the large momentum spread of the incoming positron beam.

  3. Partition of fine particles in aqueous biphase systems

    NASA Astrophysics Data System (ADS)

    Zeng, Xi

    The objective of this research project is to develop an aqueous biphase extraction process for the treatment of fine coals. Aqueous biphase extraction is an advanced separation technology that relies on the ability of an aqueous system consisting of a water-soluble polymer and another component, e.g., another polymer, an inorganic salt, or a nonionic surfactant, to separate into two immiscible aqueous phases. The principle behind the partition of solid particles in aqueous biphase systems is the physicochemical interaction between the solid surface and the surrounding liquid solution. In order to remove sulfur and mineral matter from fine coal with aqueous biphasic extraction, it is necessary to know the partitioning behavior of coal, as well as the inorganic mineral components. Therefore, in this research emphasis was placed on the partitioning behavior of fine coal particles as well as model fine inorganic particles in aqueous biphase systems. In the polyethylene glycol (PEG)/salt/H2O system, it was found that pyrite partition was highly dependent upon pH conditions: at high pH the particles preferred the salt-rich (bottom) phase, while they moved to the polymer-rich (top) phase at low pH. This behavior is attributable to the different surface oxidation products associated with the pH variations: formation of FeOOH in alkaline solution, and a hydrophobic iron-deficient product (Fe 1-xS2) in acidic environment. The partitioning behavior of oxide particles (e.g., Al2O3, Fe2O 3, SiO2, TiO2) in the PEG/Na2SO 4/H2O system indicated that, in the absence of polymer-solid interaction, the surface hydrophilic/hydrophobic properties determined solid partition; otherwise, the specific polymer-solid interaction dominated the distribution of the solid particles. Aside from the polymer/salt aqueous biphase systems, the partitioning behavior of hematite and silica was also investigated in polymer/polymer (PEG/dextran) and polymer/nonionic surfactant (Triton X-100 (TX100

  4. 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.

  5. Partition Coefficients at High Pressure and Temperature

    NASA Astrophysics Data System (ADS)

    Righter, K.; Drake, M. J.

    2003-12-01

    Differentiation of terrestrial planets includes separation of a metallic core and possible later fractionation of mineral phases within either a solid or molten mantle (Figure 1). Lithophile and siderophile elements can be used to understand these two different physical processes, and ascertain whether they operated in the early Earth. The distribution of elements in planets can be understood by measuring the partition coefficient, D (ratio of concentrations of an element in different phases (minerals, metals, or melts)). (14K)Figure 1. Schematic cross-section through the Earth, showing: (a) an early magma ocean stage and (b) a later cool and differentiated stage. The siderophile elements (iron-loving) encompass over 30 elements and are defined as those elements for which D(metal/silicate)>1, and are useful for deciphering the details of core formation. This group of elements is commonly broken up into several subclasses, including the slightly siderophile elements (1104). Because these three groups encompass a wide range of partition coefficient values, they can be very useful in trying to determine the conditions under which metal may have equilibrated with the mantle (or a magma ocean). Because metal and silicate may equilibrate by several different mechanisms, such as at the base of a deep magma ocean, or as metal droplets descend through a molten mantle, partition coefficients can potentially shed light on which mechanism may be most important, thus linking the physics and chemistry of core formation. In this chapter, we summarize metal/silicate partitioning of siderophile elements and show how they may be used to understand planetary core formation.Once a planet is differentiated into core and mantle, a mantle will cool during convection, and can start in either a molten or solid state, depending upon the initial thermal conditions. If hot enough, minerals will

  6. New Instrumentation for Phase Partitioning

    NASA Technical Reports Server (NTRS)

    Harris, J. M.

    1985-01-01

    Cells and molecules can be purified by partitioning between the two immiscible liquid phases formed by aqueous solutions of poly/ethylene glycol and dextran. Such purification can be more selective, higher yielding, and less destructive to sensitive biological materials than other available techniques. Earth's gravitational field is a hindering factor as it causes sedimentation of particles to be purified and shear-induced particle randomization. The present proposal is directed toward developing new instrumentation for performing phase partitioning both on Earth and in microgravity.

  7. THE KINETICS OF PENETRATION : VIII. TEMPORARY ACCUMULATION.

    PubMed

    Osterhout, W J; Kamerling, S E

    1934-03-20

    A model is described which throws light on the mechanism of accumulation. In the model used an external aqueous phase A is separated by a non-aqueous phase B (representing the protoplasm) from the artificial sap in C. A contains KOH and C contains HCl: they tend to mix by passing through the non-aqueous layer but much more KOH moves so that most of the KCl is formed in C, where the concentration of potassium becomes much greater than in A. This accumulation is only temporary for as the system approaches equilibrium the composition of A approaches identity with that of C, since all the substances present can pass through the non-aqueous layer. Such an approach to equilibrium may be compared to the death of the cell as the result of which accumulation disappears. During the earlier stages of the experiment potassium tends to go in as KOH and at the same time to go out as KCl. These opposing tendencies do not balance until the concentration of potassium inside becomes much greater than outside (hence potassium accumulates). The reason is that KCl, although its driving force be great, moves very slowly in B because its partition coefficient is low and in consequence its concentration gradient in B is small. This illustrates the importance of partition coefficients for penetration in models and in living cells. It also indicates that accumulation depends on the fact that permeability is greater for the ingoing compound of the accumulating substance than for the outgoing compound. Other things being equal, accumulation is increased by maintaining a low pH in C. Hence we may infer that anything which checks the production of acid in the living cell may be expected to check accumulation and growth. This model recalls the situation in Valonia and in most living cells where potassium accumulates as KCl, perhaps because it enters as KOH and forms KA in the sap (where A is an organic anion). In some plants potassium accumulates as KA but when HCl exists in the external

  8. Rectilinear partitioning of irregular data parallel computations

    NASA Technical Reports Server (NTRS)

    Nicol, David M.

    1991-01-01

    New mapping algorithms for domain oriented data-parallel computations, where the workload is distributed irregularly throughout the domain, but exhibits localized communication patterns are described. Researchers consider the problem of partitioning the domain for parallel processing in such a way that the workload on the most heavily loaded processor is minimized, subject to the constraint that the partition be perfectly rectilinear. Rectilinear partitions are useful on architectures that have a fast local mesh network. Discussed here is an improved algorithm for finding the optimal partitioning in one dimension, new algorithms for partitioning in two dimensions, and optimal partitioning in three dimensions. The application of these algorithms to real problems are discussed.

  9. Effect of Lipid Partitioning on Predictions of Acute Toxicity of Oil Sands Process Affected Water to Embryos of Fathead Minnow (Pimephales promelas).

    PubMed

    Morandi, Garrett D; Zhang, Kun; Wiseman, Steve B; Pereira, Alberto Dos Santos; Martin, Jonathan W; Giesy, John P

    2016-08-16

    Dissolved organic compounds in oil sands process affected water (OSPW) are known to be responsible for most of its toxicity to aquatic organisms, but the complexity of this mixture prevents use of traditional bottom-up approaches for predicting toxicities of mixtures. Therefore, a top-down approach to predict toxicity of the dissolved organic fraction of OSPW was developed and tested. Accurate masses (i.e., m/z) determined by ultrahigh resolution mass spectrometry in negative and positive ionization modes were used to assign empirical chemical formulas to each chemical species in the mixture. For each chemical species, a predictive measure of lipid accumulation was estimated by stir-bar sorptive extraction (SBSE) to poly(dimethyl)siloxane, or by partitioning to solid-supported lipid membranes (SSLM). A narcosis mode of action was assumed and the target-lipid model was used to estimate potencies of mixtures by assuming strict additivity. A model developed using a combination of the SBSE and SSLM lipid partitioning estimates, whereby the accumulation of chemicals to neutral and polar lipids was explicitly considered, was best for predicting empirical values of LC50 in 96-h acute toxicity tests with embryos of fathead minnow (Pimephales promelas). Model predictions were within 4-fold of observed toxicity for 75% of OSPW samples, and within 8.5-fold for all samples tested, which is comparable to the range of interlaboratory variability for in vivo toxicity testing. PMID:27420640

  10. Investigation into the determination of trimethylarsine in natural gas and its partitioning into gas and condensate phases using (cryotrapping)/gas chromatography coupled to inductively coupled plasma mass spectrometry and liquid/solid sorption techniques

    NASA Astrophysics Data System (ADS)

    Krupp, E. M.; Johnson, C.; Rechsteiner, C.; Moir, M.; Leong, D.; Feldmann, J.

    2007-09-01

    Speciation of trialkylated arsenic compunds in natural gas, pressurized and stable condensate samples from the same gas well was performed using (Cryotrapping) Gas Chromatography-Inductively Coupled Plasma Mass Spectrometry. The major species in all phases investigated was found to be trimethylarsine with a highest concentration of 17.8 ng/L (As) in the gas phase and 33.2 μg/L (As) in the stable condensate phase. The highest amount of trimethylarsine (121 μg/L (As)) was found in the pressurized condensate, along with trace amounts of non-identified higher alkylated arsines. Volatile arsenic species in natural gas and its related products cause concern with regards to environment, safety, occupational health and gas processing. Therefore, interest lies in a fast and simple field method for the determination of volatile arsenicals. Here, we use simple liquid and solid sorption techniques, namely absorption in silver nitrate solution and adsorption on silver nitrate impregnated silica gel tubes followed by total arsenic determination as a promising tool for field monitoring of volatile arsenicals in natural gas and gas condensates. Preliminary results obtained for the sorption-based methods show that around 70% of the arsenic is determined with these methods in comparison to volatile arsenic determination using GC-ICP-MS. Furthermore, an inter-laboratory- and inter-method comparison was performed using silver nitrate impregnated silica tubes on 14 different gas samples with concentrations varying from below 1 to 1000 μg As/m 3 natural gas. The results obtained from the two laboratories differ in a range of 10 to 60%, but agree within the order of magnitude, which is satisfactory for our purposes.

  11. Monomial Crystals and Partition Crystals

    NASA Astrophysics Data System (ADS)

    Tingley, Peter

    2010-04-01

    Recently Fayers introduced a large family of combinatorial realizations of the fundamental crystal B(Λ0) for ^sln, where the vertices are indexed by certain partitions. He showed that special cases of this construction agree with the Misra-Miwa realization and with Berg's ladder crystal. Here we show that another special case is naturally isomorphic to a realization using Nakajima's monomial crystal.

  12. Set covering, partition and packing

    SciTech Connect

    Hulme, B.L.; Baca, L.S.

    1984-03-01

    Set covering problems are known to be solvable by Boolean algebraic methods. This report shows that set partition and set packing problems can be solved by the same algebraic methods because these problems can be converted into covering problems. Many applications are possible including security patrol assignment which is used as an example.

  13. 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...

  14. 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.

  15. Terminology for trace-element partitioning

    SciTech Connect

    Beattie, P. ); Drake, M. ); Jones, J.; McKay, G. ); Leeman, W. ); Longhi, J. ); Nielsen, R. ); Palme, H. ); Shaw, D. ); Takahashi, E. ); Watson, B. )

    1993-04-01

    A self-consistent terminology for partitioning data is presented. Ratios of the concentration of a component in two phases are termed partition coefficients and given the symbol D. Ratios of partition coefficients are termed exchange coefficients and given the symbol K[sub D]. The prefix bulk implies that these coefficients are weighted according to the proportions of coexisting phases. Bulk partition and bulk exchange coefficients are denoted by [bar D] and [ovr K[sub D

  16. Methodology for optimally sized centrifugal partition chromatography columns.

    PubMed

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

    2015-04-01

    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. PMID:25744547

  17. Equilibrium partitioning of Ficoll in composite hydrogels.

    PubMed

    Kosto, Kimberly B; Panuganti, Swapna; Deen, William M

    2004-09-15

    Equilibrium partition coefficients (phi, the concentration in the gel divided by that in free solution) of fluorescein-labeled Ficolls in pure agarose and agarose-dextran composite gels were measured as a function of gel composition and Ficoll size. The four narrow fractions of Ficoll, a spherical polysaccharide, had Stokes-Einstein radii ranging from 2.7 to 5.9 nm. Gels with agarose volume fractions of 0.040 and 0.080 were studied, with dextran volume fractions (calculated as if the chain were a long fiber) up to 0.011. As expected, phi generally decreased as the Ficoll size increased (for a given gel composition) or as the amount of dextran incorporated into the gel increased (for a given agarose concentration and Ficoll size). The decrease in phi that accompanied dextran addition was predicted well by an excluded volume theory in which agarose and dextran were both treated as rigid, straight, randomly positioned and oriented fibers. Modeling dextran as a spherical coil within a fibrous agarose gel produced much less accurate predictions. The diffusional permeabilities of these gels were assessed by combining the current partitioning data with relative diffusivities (Kd, the diffusivity in the gel divided by that in free solution) reported previously. The values of phi Kd for a synthetic gel with 8.0% agarose and 1.1% dextran (by volume) were found to be very similar to those for the glomerular basement membrane, a physiologically important material which also has a total solids content of approximately 10%. PMID:15341852

  18. 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.

  19. Interseismic Plate coupling and strain partitioning in the Northeastern Caribbean

    NASA Astrophysics Data System (ADS)

    Manaker, D. M.; Calais, E.; Freed, A. M.; Ali, S. T.; Przybylski, P.; Mattioli, G.; Jansma, P.; Prépetit, C.; de Chabalier, J. B.

    2008-09-01

    The northeastern Caribbean provides a natural laboratory to investigate strain partitioning, its causes and its consequences on the stress regime and tectonic evolution of a subduction plate boundary. Here, we use GPS and earthquake slip vector data to produce a present-day kinematic model that accounts for secular block rotation and elastic strain accumulation, with variable interplate coupling, on active faults. We confirm that the oblique convergence between Caribbean and North America in Hispaniola is partitioned between plate boundary parallel motion on the Septentrional and Enriquillo faults in the overriding plate and plate-boundary normal motion at the plate interface on the Northern Hispaniola Fault. To the east, the Caribbean/North America plate motion is accommodated by oblique slip on the faults bounding the Puerto Rico block to the north (Puerto Rico subduction) and to the south (Muertos thrust), with no evidence for partitioning. The spatial correlation between interplate coupling, strain partitioning and the subduction of buoyant oceanic asperities suggests that the latter enhance the transfer of interplate shear stresses to the overriding plate, facilitating strike-slip faulting in the overriding plate. The model slip rate deficit, together with the dates of large historical earthquakes, indicates the potential for a large (Mw7.5 or greater) earthquake on the Septentrional fault in the Dominican Republic. Similarly, the Enriquillo fault in Haiti is currently capable of a Mw7.2 earthquake if the entire elastic strain accumulated since the last major earthquake was released in a single event today. The model results show that the Puerto Rico/Lesser Antilles subduction thrust is only partially coupled, meaning that the plate interface is accumulating elastic strain at rates slower than the total plate motion. This does not preclude the existence of isolated locked patches accumulating elastic strain to be released in future earthquakes, but whose

  20. 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.

  1. Consolidated Incineration Facility metals partitioning test. Final report

    SciTech Connect

    Burns, D.B.

    1993-08-31

    Test burns were conducted at Energy and Environmental Research Corporation`s rotary kiln simulator, the Solid Waste Incineration Test Facility, using surrogate CIF wastes spiked with hazardous metals and organics. The primary objective for this test program was measuring heavy metals partition between the kiln bottom ash, scrubber blowdown solution, and incinerator stack gas. Also, these secondary waste streams were characterized to determine waste treatment requirements prior to final disposal. These tests were designed to investigate the effect of several parameters on metals partitioning: incineration temperature; waste chloride concentration; waste form (solid or liquid); and chloride concentration in the scrubber water. Tests were conducted at three kiln operating temperatures. Three waste simulants were burned, two solid waste mixtures (paper, plastic, latex, and one with and one without PVC), and a liquid waste mixture (containing benzene and chlorobenzene). Toxic organic and metal compounds were spiked into the simulated wastes to evaluate their fate under various combustion conditions. Kiln offgases were sampled for volatile organic compounds (VOC), semi-volatile organic compounds (SVOC), polychlorinated dibenz[p]dioxins and polychlorinated dibenzofurans (PCDD/PCDF), metals, particulate loading and size distribution, HCl, and combustion products. Stack gas sampling was performed to determine additional treatment requirements prior to final waste disposal. Significant test results are summarized below.

  2. About Thinning Invariant Partition Structures

    NASA Astrophysics Data System (ADS)

    Starr, Shannon; Vermesi, Brigitta; Wei, Ang

    2012-08-01

    Bernoulli- p thinning has been well-studied for point processes. Here we consider three other cases: (1) sequences ( X 1, X 2,…); (2) gaps of such sequences ( X n+1- X 1) n∈ℕ; (3) partition structures. For the first case we characterize the distributions which are simultaneously invariant under Bernoulli- p thinning for all p∈(0,1]. Based on this, we make conjectures for the latter two cases, and provide a potential approach for proof. We explain the relation to spin glasses, which is complementary to important previous work of Aizenman and Ruzmaikina, Arguin, and Shkolnikov.

  3. 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.

  4. Partitioning of divalent transition elements between octahedral sheets of trioctahedral smectites and water

    NASA Astrophysics Data System (ADS)

    Decarreau, Alain

    1985-07-01

    Using trioctahedral smectites synthesized at low temperature (25 and 75°C). partition coefficients have been determined for M2+ transition metals (Mn, Fe, Co, Ni, Cu, Zn) between octahedral sheets of smectites and water. These coefficients D( M2+- Mg) = ( M2+)/( Mg) solid/( M2+)/( Mg) liquid have high values near 10 4 for Cu, 1000 for Ni, Co, Zn, 300 for Fe and 30 for Mn. All transition metals are strongly stabilized in the magnesian solid phase, even Mn which leads to noncrystallized products. Within the range of experimental uncertainties, it is found that tetrahedral substitution of Si by Al and differences in temperature (from 25 to 75°C) have no influence on partition coefficients. Experimental data are closely related to thermodynamic properties of the cations and on this basis other partition coefficients can be calculated, for the ( M2+ - Fe2+) pair for instance. The behaviour of transition metals is explained using crystal field theory.

  5. 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.

  6. 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

  7. 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.

  8. Parameters of photosynthetic energy partitioning.

    PubMed

    Lazár, Dušan

    2015-03-01

    Almost every laboratory dealing with plant physiology, photosynthesis research, remote sensing, and plant phenotyping possesses a fluorometer to measure a kind of chlorophyll (Chl) fluorescence induction (FLI). When the slow Chl FLI is measured with addition of saturating pulses and far-red illumination, the so-called quenching analysis followed by the so-called relaxation analysis in darkness can be realized. These measurements then serve for evaluation of the so-called energy partitioning, that is, calculation of quantum yields of photochemical and of different types of non-photochemical processes. Several theories have been suggested for photosynthetic energy partitioning. The current work aims to summarize all the existing theories, namely their equations for the quantum yields, their meaning and their assumptions. In the framework of these theories it is also found here that the well-known NPQ parameter ( [Formula: see text] ; Bilger and Björkman, 1990) equals the ratio of the quantum yield of regulatory light-induced non-photochemical quenching to the quantum yield of constitutive non-regulatory non-photochemical quenching (ΦNPQ/Φf,D). A similar relationship is also found here for the PQ parameter (ΦP/Φf,D). PMID:25569797

  9. Mass partitioning effects in diffusion transport.

    PubMed

    Kojic, Milos; Milosevic, Miljan; Wu, Suhong; Blanco, Elvin; Ferrari, Mauro; Ziemys, Arturas

    2015-08-28

    Frequent mass exchange takes place in a heterogeneous environment among several phases, where mass partitioning may occur at the interface of phases. Analytical and computational methods for diffusion do not usually incorporate molecule partitioning masking the true picture of mass transport. Here we present a computational finite element methodology to calculate diffusion mass transport with a partitioning phenomenon included and the analysis of the effects of partitioning. Our numerical results showed that partitioning controls equilibrated mass distribution as expected from analytical solutions. The experimental validation of mass release from drug-loaded nanoparticles showed that partitioning might even dominate in some cases with respect to diffusion itself. The analysis of diffusion kinetics in the parameter space of partitioning and diffusivity showed that partitioning is an extremely important parameter in systems, where mass diffusivity is fast and that the concentration of nanoparticles can control payload retention inside nanoparticles. The computational and experimental results suggest that partitioning and physiochemical properties of phases play an important, if not crucial, role in diffusion transport and should be included in the studies of mass transport processes. PMID:26204522

  10. A Henry's Law Test for Experimental Partitioning Studies of Iron Meteorites

    NASA Technical Reports Server (NTRS)

    Chabot, N. L.; Campbell, A. J.; Humayun, M.; Agee, C. B.

    2001-01-01

    Low-level doped solid metal/liquid metal experiments analyzed by laser ablation ICP-MS allow Henry's Law to be tested. The results indicate Henry's Law is obeyed and the experimental partition coefficients can be applied to iron meteorites. Additional information is contained in the original extended abstract.

  11. 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. PMID:27211313

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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…

  17. A Partitioning Technique for Defining Instructional Groups.

    ERIC Educational Resources Information Center

    Baker, Frank B.; Hubert, Lawrence J.

    1979-01-01

    A technique is presented for partitioning N students into K groups of fixed sizes using a given measure of proximity for all student pairs. The measure of proximity is typically calculated from a set of variables and constitutes the data needed for a criterion of partition "fit." (Author)

  18. 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. PMID:19261379

  19. Prediction of Partition Coefficients of Organic Compounds between SPME/PDMS and Aqueous Solution

    PubMed Central

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

    2014-01-01

    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. PMID:24534804

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

    PubMed

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

    2014-01-01

    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. PMID:24534804

  1. 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.

  2. 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.

  3. Bicriterion methods for partitioning dissimilarity matrices.

    PubMed

    Brusco, Michael J; Cradit, J Dennis

    2005-11-01

    Partitioning indices associated with the within-cluster sums of pairwise dissimilarities often exhibit a systematic bias towards clusters of a particular size, whereas minimization of the partition diameter (i.e. the maximum dissimilarity element across all pairs of objects within the same cluster) does not typically have this problem. However, when the partition-diameter criterion is used, there is often a myriad of alternative optimal solutions that can vary significantly with respect to their substantive interpretation. We propose a bicriterion partitioning approach that considers both diameter and within-cluster sums in the optimization problem and facilitates selection from among the alternative optima. We developed several MATLAB-based exchange algorithms that rapidly provide excellent solutions to bicriterion partitioning problems. These algorithms were evaluated using synthetic data sets, as well as an empirical dissimilarity matrix. PMID:16293203

  4. 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.

  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. Dense Subgraph Partition of Positive Hypergraphs.

    PubMed

    Liu, Hairong; Latecki, Longin Jan; Yan, Shuicheng

    2015-03-01

    In this paper, we present a novel partition framework, called dense subgraph partition (DSP), to automatically, precisely and efficiently decompose a positive hypergraph into dense subgraphs. A positive hypergraph is a graph or hypergraph whose edges, except self-loops, have positive weights. We first define the concepts of core subgraph, conditional core subgraph, and disjoint partition of a conditional core subgraph, then define DSP based on them. The result of DSP is an ordered list of dense subgraphs with decreasing densities, which uncovers all underlying clusters, as well as outliers. A divide-and-conquer algorithm, called min-partition evolution, is proposed to efficiently compute the partition. DSP has many appealing properties. First, it is a nonparametric partition and it reveals all meaningful clusters in a bottom-up way. Second, it has an exact and efficient solution, called min-partition evolution algorithm. The min-partition evolution algorithm is a divide-and-conquer algorithm, thus time-efficient and memory-friendly, and suitable for parallel processing. Third, it is a unified partition framework for a broad range of graphs and hypergraphs. We also establish its relationship with the densest k-subgraph problem (DkS), an NP-hard but fundamental problem in graph theory, and prove that DSP gives precise solutions to DkS for all kin a graph-dependent set, called critical k-set. To our best knowledge, this is a strong result which has not been reported before. Moreover, as our experimental results show, for sparse graphs, especially web graphs, the size of critical k-set is close to the number of vertices in the graph. We test the proposed partition framework on various tasks, and the experimental results clearly illustrate its advantages. PMID:26353260

  7. Fast carry accumulator design

    NASA Technical Reports Server (NTRS)

    Mastin, W. C.

    1971-01-01

    Simple iterative accumulator combined with gated-carry, carry-completion detection, and skip-carry circuits produces three accumulators with decreased carry propagation times. Devices are used in machine control, measurement equipment, and computer applications to increase speed of binary addition. NAND gates are used in combining network.

  8. [Effects of chlorides on Cd partitioning and speciation in a simulated MSW incinerator].

    PubMed

    Chen, Yong; Zhang, Yan-Guo; Li, Qing-Hai; Zhuo, Yu-Qun; Chen, Chang-He

    2008-05-01

    The effects of chlorides (including inorganic chloride NaCl and organic chloride PVC) on Cd emission in MSW (municipal solid waste) incineration was investigated using a simulated tubular furnace and the simulated MSW spiked with heavy metals. The concentrations of heavy metals were measured by ICP-AES after the digesting of samples including bottom ash, fly ash and flue gas according to related USEPA Methods. Heavy metal species in bottom ash and fly ash were identified by X-ray diffraction technique and the spectra of elements distributed and micrographs of bottom ash and fly ash were detected by energy dispersive X-ray system and scanning electron microscope, respectively. The results indicated that the emission of Cd tended to be enhanced with the increasing of chloride content, and 97% Cd partitioned in fly ash after spiked chlorides. However, the content effect of inorganic chloride NaCl and inorganic chloride PVC on Cd emission had no significant difference. The effect of PVC on Cd partitioning was affected by temperature, 80.51% Cd partitioned in fly ash at 550 degrees C and 97.91% Cd partitioned in fly ash at 850 degrees C, when temperature went above the melting point of CdCl2 (568 degrees C), the effect of temperature became less important. The effect of NaCl on Cd partitioning was not affected by temperature, 95.02% Cd partitioned in fly ash at 550 degrees C and 96.58% Cd partitioned at 1 000 degrees C when spiked NaCl. Residence time had no significant effect on Cd partitioning with spiked chlorides. The two different mechanisms of chlorides effects on Cd emission were identified by bottom ash and fly ash analysis using SEM/EDS and XRD technique. PMID:18624222

  9. 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

  10. Chalcophile element partitioning into magmatic sulphides: the effect of silicate melt composition

    NASA Astrophysics Data System (ADS)

    Kiseeva, Kate; Wood, Bernard

    2016-04-01

    Partitioning of many elements between sulphide and silicate melts is a function of the FeO content of the silicate liquid (Kiseeva and Wood, 2013). The theoretical relationship is a linear one between LogDM (DM=[M]sulph/[M]sil) and -log[FeO] with a slope of n/2, where n is the valency of trace element M. In practice we find that the slope deviates from the theoretical one because of the presence of oxygen in the sulphide. In our recent study we investigated the effects of sulphide composition and temperature on chalcophile element partitioning between sulphide and silicate liquids (Kiseeva and Wood, 2015). We have concluded that partitioning of most chalcophile elements is a strong function of the oxygen (or FeO) content of the sulphide. As expected, lithophile elements partition more strongly into sulphide as its oxygen content increases, while chalcophile elements enter sulphide less readily with increasing oxygen. The effect of Ni and Cu content of sulphide is significantly smaller than the effect of oxygen, while the effects of temperature are large only for a number of elements (such as Ni, Cu, Ag). In this study we show that in addition to the effect of sulphide composition, for certain elements the effect of silicate melt composition on sulphide/silicate partitioning can be quite large. For instance, within the range of NBO/T between 0.5 and 2 the DTlsulph/sil changes in order of magnitude. For the elements, like Pb, partition coefficient does not seem to change much with the silicate melt composition, while for Sb the effect of the silicate melt composition on D is a factor of 3. Partitioning of chalcophile elements into more evolved, alkali-rich and felsic magmas is estimated to be very different from the partitioning into basaltic melts, mainly due to the strong effects of temperature and alkali components. Although it is highly likely that sulphide is in solid form at liquidus temperatures for dacite and rhyolite and thus the partitioning of chalcophile

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

    PubMed

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

    2009-06-01

    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. PMID:19414174

  12. 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...

  13. 40 CFR 273.35 - Accumulation time limits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Accumulation time limits. 273.35 Section 273.35 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR UNIVERSAL WASTE MANAGEMENT Standards for Large Quantity Handlers of Universal Waste § 273.35 Accumulation time limits. (a) A...

  14. 40 CFR 273.15 - Accumulation time limits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Accumulation time limits. 273.15 Section 273.15 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR UNIVERSAL WASTE MANAGEMENT Standards for Small Quantity Handlers of Universal Waste § 273.15 Accumulation time limits. (a) A...

  15. Selecting optimal partitioning schemes for phylogenomic datasets

    PubMed Central

    2014-01-01

    Background Partitioning involves estimating independent models of molecular evolution for different subsets of sites in a sequence alignment, and has been shown to improve phylogenetic inference. Current methods for estimating best-fit partitioning schemes, however, are only computationally feasible with datasets of fewer than 100 loci. This is a problem because datasets with thousands of loci are increasingly common in phylogenetics. Methods We develop two novel methods for estimating best-fit partitioning schemes on large phylogenomic datasets: strict and relaxed hierarchical clustering. These methods use information from the underlying data to cluster together similar subsets of sites in an alignment, and build on clustering approaches that have been proposed elsewhere. Results We compare the performance of our methods to each other, and to existing methods for selecting partitioning schemes. We demonstrate that while strict hierarchical clustering has the best computational efficiency on very large datasets, relaxed hierarchical clustering provides scalable efficiency and returns dramatically better partitioning schemes as assessed by common criteria such as AICc and BIC scores. Conclusions These two methods provide the best current approaches to inferring partitioning schemes for very large datasets. We provide free open-source implementations of the methods in the PartitionFinder software. We hope that the use of these methods will help to improve the inferences made from large phylogenomic datasets. PMID:24742000

  16. 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.

  17. 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.

  18. Convex Regression with Interpretable Sharp Partitions

    PubMed Central

    Petersen, Ashley; Simon, Noah; Witten, Daniela

    2016-01-01

    We consider the problem of predicting an outcome variable on the basis of a small number of covariates, using an interpretable yet non-additive model. We propose convex regression with interpretable sharp partitions (CRISP) for this task. CRISP partitions the covariate space into blocks in a data-adaptive way, and fits a mean model within each block. Unlike other partitioning methods, CRISP is fit using a non-greedy approach by solving a convex optimization problem, resulting in low-variance fits. We explore the properties of CRISP, and evaluate its performance in a simulation study and on a housing price data set.

  19. Quantum Dilogarithms and Partition q-Series

    NASA Astrophysics Data System (ADS)

    Kato, Akishi; Terashima, Yuji

    2015-08-01

    In our previous work (Kato and Terashima, Commun Math Phys. arXiv:1403.6569, 2014), we introduced the partition q-series for mutation loop γ—a loop in exchange quiver. In this paper, we show that for a certain class of mutation sequences, called reddening sequences, the graded version of partition q-series essentially coincides with the ordered product of quantum dilogarithm associated with each mutation; the partition q-series provides a state-sum description of combinatorial Donaldson-Thomas invariants introduced by Keller.

  20. How pervasive is the Hirshfeld partitioning?

    SciTech Connect

    Heidar-Zadeh, Farnaz; Ayers, Paul W.

    2015-01-28

    One can partition the molecular density into its atomic contributions by minimizing the divergence of the atom-in-molecule densities from their corresponding reference pro-atomic densities, subject to the constraint that the sum of the atom-in-molecule densities is the total molecular density. We expose conditions on the divergence measure that are necessary, and sufficient, to recover the popular Hirshfeld partitioning. Specifically, among all local measures of the divergence between two probability distribution functions, the Hirshfeld partitioning is obtained only for f-divergences.

  1. Partitioning technique for open systems

    NASA Astrophysics Data System (ADS)

    Brändas, Erkki J.

    2010-11-01

    The focus of the present contribution is essentially confined to three research areas carried out during the author's turns as visiting (assistant, associate and full) professor at the University of Florida's Quantum Theory Project, QTP. The first two topics relate to perturbation theory and spectral theory for self-adjoint operators in Hilbert space. The third subject concerns analytic extensions to non-self-adjoint problems, where particular consequences of the occurrence of continuous energy spectra are measured. In these studies general partitioning methods serve as general cover for perturbation-, variational- and general matrix theory. In addition we follow up associated inferences for the time dependent problem as well as recent results and conclusions of a rather general yet surprising character. Although the author spent most of his times at QTP during visits in the 1970s and 1980s, collaborations with department members and shorter stays continued through later decades. Nevertheless the impact must be somewhat fragmentary, yet it is hoped that the present account is sufficiently self-contained to be realistic and constructive.

  2. Lipid partitioning during cardiac stress.

    PubMed

    Kolwicz, Stephen C

    2016-10-01

    It is well documented that fatty acids serve as the primary fuel substrate for the contracting myocardium. However, extensive research has identified significant changes in the myocardial oxidation of fatty acids during acute or chronic cardiac stress. As a result, the redistribution or partitioning of fatty acids due to metabolic derangements could have biological implications. Fatty acids can be stored as triacylglycerols, serve as critical components for biosynthesis of phospholipid membranes, and form the potent signaling molecules, diacylglycerol and ceramides. Therefore, the contribution of lipid metabolism to health and disease is more intricate than a balance of uptake and oxidation. In this review, the available data regarding alterations that occur in endogenous cardiac lipid pathways during the pathological stressors of ischemia-reperfusion and pathological hypertrophy/heart failure are highlighted. In addition, changes in endogenous lipids observed in exercise training models are presented for comparison. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk. PMID:27040509

  3. HPAM: Hirshfeld Partitioned Atomic Multipoles

    PubMed Central

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

    2011-01-01

    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 lmax 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 lmax = 0 (atomic charges) to lmax = 4 (atomic hexadecapoles). Both HD and HD-I atomic multipoles up to rank lmax are shown to exactly reproduce ab initio molecular multipole moments of rank L for L ≤ lmax. In addition, molecular dipole moments calculated by HD, HD-I, and ChelpG atomic charges only (lmax = 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. PMID:22140274

  4. 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.

  5. Energy partitioning schemes: a dilemma.

    PubMed

    Mayer, I

    2007-01-01

    Two closely related energy partitioning schemes, in which the total energy is presented as a sum of atomic and diatomic contributions by using the "atomic decomposition of identity", are compared on the example of N,N-dimethylformamide, a simple but chemically rich molecule. Both schemes account for different intramolecular interactions, for instance they identify the weak C-H...O intramolecular interactions, but give completely different numbers. (The energy decomposition scheme based on the virial theorem is also considered.) The comparison of the two schemes resulted in a dilemma which is especially striking when these schemes are applied for molecules distorted from their equilibrium structures: one either gets numbers which are "on the chemical scale" and have quite appealing values at the equilibrium molecular geometries, but exhibiting a counter-intuitive distance dependence (the two-center energy components increase in absolute value with the increase of the interatomic distances)--or numbers with too large absolute values but "correct" distance behaviour. The problem is connected with the quick decay of the diatomic kinetic energy components. PMID:17328441

  6. Actinide partitioning processes for fuel reprocessing and refabrication plant wastes

    SciTech Connect

    Finney, B.C.; Tedder, D.W.

    1980-01-01

    Chemical processing methods have been developed on a laboratory scale to partition the actinides from the liquid and solid fuel reprocessing plant (FRP) and refabrication plant (FFP) wastes. It was envisioned that these processes would be incorporated into separate waste treatment facilities (WTFs) that are adjacent to, but not integrated with, the fuel reprocessing and refabrication plants. Engineering equipment and material balance flowsheets have been developed for WTFs in support of a 2000-MTHM/year FRP and a 660-MTHM/year MOX-FFP. The processing subsystems incorporated in the FRP-WTF are: High-Level Solid Waste Treatment, High-Level Liquid Waste Treatment, Solid Alpha Waste Treatment, Cation Exchange Chromatography, Salt Waste Treatment, Actinide Recovery, Solvent Cleanup and recycle, Off-Gas Treatment, Actinide Product Concentration, and Acid and Water Recycle. The WTF supporting a fuel refabrication facility, although similar, does not contain subsystems (1) and (2). Based on the results of the laboratory and hot-cell experimental work, we believe that the processes and flowsheets offer the potential to reduce the total unrecovered actinides in FRP and FFP wastes to less than or equal to 0.25%. The actinide partitioning processes and the WTF concept represent advanced technology that would require substantial work before commercialization. It is estimated that an orderly development program would require 15 to 20 years to complete and would cost about 700 million 1979 dollars. It is estimated that the capital cost and annual operating cost, in mid-1979 dollars, for the FRP-WTF are $1035 million and $71.5 million/year, and for the FFP-WTF are $436 million and $25.6 million/year, respectively.

  7. 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.

  8. 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.

  9. 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.

  10. 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. PMID:27463671

  11. 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.

  12. 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.

  13. Isorropia Partitioning and Load Balancing Package

    Energy Science and Technology Software Center (ESTSC)

    2006-09-01

    Isorropia is a partitioning and load balancing package which interfaces with the Zoltan library. Isorropia can accept input objects such as matrices and matrix-graphs, and repartition/redistribute them into a better data distribution on parallel computers. Isorropia is primarily an interface package, utilizing graph and hypergraph partitioning algorithms that are in the Zoltan library which is a third-party library to Tilinos.

  14. Deriving the Hirshfeld partitioning using distance metrics

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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.

  15. Software Partitioning Schemes for Advanced Simulation Computer Systems. Final Report.

    ERIC Educational Resources Information Center

    Clymer, S. J.

    Conducted to design software partitioning techniques for use by the Air Force to partition a large flight simulator program for optimal execution on alternative configurations, this study resulted in a mathematical model which defines characteristics for an optimal partition, and a manually demonstrated partitioning algorithm design which…

  16. Experimental investigations of trace element fractionation in iron meteorites. III - Elemental partitioning in the system Fe-Ni-S-P

    NASA Technical Reports Server (NTRS)

    Malvin, D. J.; Jones, J. H.; Drake, M. J.

    1986-01-01

    Measurements of solid metal/liquid metal trace element partition coefficients, which are used to interpret the crystallization history of magmatic iron meteorite groups differ greatly between different research groups, using different experimental techniques. Specifically, partition coefficients measured utilizing 'static' experiments which approach equilibrium cannot be reconciled with the results of 'dynamic' experiments which mimic fractional crystallization. We report new tests of our 'static' experimental technique and demonstrate that our methodology yields reliable equilibrium values for Ni, P and Ge partition coefficients. Partition coefficients in the Fe-Ni-S-P system are well matched by interpolation between the Fe-Ni-S and Fe-Ni-P subsystems. In contrast, the predictions of 'dynamic' experiments do not agree with our measurements and, consequently, the ability of 'dynamic' experiments to reproduce iron meteorite Ge vs. Ni fractionation trends successfully must be regarded as fortuitous.

  17. Atmospheric amines - Part II. Thermodynamic properties and gas/particle partitioning

    NASA Astrophysics Data System (ADS)

    Ge, Xinlei; Wexler, Anthony S.; Clegg, Simon L.

    2011-01-01

    Amines enter the atmosphere from a wide range of sources, but relatively little is known about their atmospheric behavior, especially their role in gas/particle partitioning. In Part I of this work ( Ge et al., 2011) a total of 154 amines, 32 amino acids and urea were identified as occurring in the atmosphere, based upon a survey of the literature. In this work we compile data for the thermodynamic properties of the amines which control gas/particle partitioning (Henry's Law constant, liquid vapor pressure, acid dissociation constant, activity coefficient and solubility in water), and also estimate the solid/gas dissociation constants of their nitrate and chloride salts. Prediction methods for boiling point, liquid vapor pressure, acid dissociation constant and the solubility of the amines in water are evaluated, and used to estimate values of the equilibrium constants where experimental data are lacking. Partitioning of amines into aqueous aerosols is strongly dependent upon pH and is greatest for acidic aerosols. For several common amines the tendency to partition to the particle phase is similar to or greater than that of ammonia. Our results are presented as tables of values of thermodynamic equilibrium constants, which are also incorporated into the Extended Aerosol Inorganics Model ( E-AIM, http://www.aim.env.uea.ac.uk/aim/aim.php) to enable gas/aerosol partitioning and other calculations to be carried out.

  18. Neurodegeneration with Brain Iron Accumulation

    MedlinePlus

    ... Diversity Find People About NINDS NINDS Neurodegeneration with Brain Iron Accumulation Information Page Synonym(s): Hallervorden-Spatz Disease, ... done? Clinical Trials Organizations What is Neurodegeneration with Brain Iron Accumulation? Neurodegeneration with brain iron accumulation (NBIA) ...

  19. Plastids and Carotenoid Accumulation.

    PubMed

    Li, Li; Yuan, Hui; Zeng, Yunliu; Xu, Qiang

    2016-01-01

    Plastids are ubiquitously present in plants and are the organelles for carotenoid biosynthesis and storage. Based on their morphology and function, plastids are classified into various types, i.e. proplastids, etioplasts, chloroplasts, amyloplasts, and chromoplasts. All plastids, except proplastids, can synthesize carotenoids. However, plastid types have a profound effect on carotenoid accumulation and stability. In this chapter, we discuss carotenoid biosynthesis and regulation in various plastids with a focus on carotenoids in chromoplasts. Plastid transition related to carotenoid biosynthesis and the different capacity of various plastids to sequester carotenoids and the associated effect on carotenoid stability are described in light of carotenoid accumulation in plants. PMID:27485226

  20. 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)

  1. Exact Potts model partition functions on ladder graphs

    NASA Astrophysics Data System (ADS)

    Shrock, Robert

    2000-08-01

    We present exact calculations of the partition function Z of the q-state Potts model and its generalization to real q, for arbitrary temperature on n-vertex ladder graphs, i.e., strips of the square lattice with width Ly=2 and arbitrary length Lx, with free, cyclic, and Möbius longitudinal boundary conditions. These partition functions are equivalent to Tutte/Whitney polynomials for these graphs. The free energy is calculated exactly for the infinite-length limit of these ladder graphs and the thermodynamics is discussed. By comparison with strip graphs of other widths, we analyze how the singularities at the zero-temperature critical point of the ferromagnet on infinite-length, finite-width strips depend on the width. We point out and study the following noncommutativity at certain special values q s: lim n→∞ limq→q s Z 1/n≠ limq→q s limn→∞ Z 1/n. It is shown that the Potts antiferromagnet on both the infinite-length line and ladder graphs with cyclic or Möbius boundary conditions exhibits a phase transition at finite temperature if 0< q<2, but with unphysical properties, including negative specific heat and non-existence, in the low-temperature phase, of an n→∞ limit for thermodynamic functions that is independent of boundary conditions. Considering the full generalization to arbitrary complex q and temperature, we determine the singular locus B in the corresponding C2 space, arising as the accumulation set of partition function zeros as n→∞. In particular, we study the connection with the T=0 limit of the Potts antiferromagnet where B reduces to the accumulation set of chromatic zeros. Certain properties of the complex-temperature phase diagrams are shown to exhibit close connections with those of the model on the square lattice, showing that exact solutions on infinite-length strips provide a way of gaining insight into these complex-temperature phase diagrams.

  2. Tracers in recharge — Effects of partitioning in soils

    NASA Astrophysics Data System (ADS)

    Gerritse, Robert G.; Adeney, John A.

    1992-02-01

    Partitioning among mobile and stationary water phases in a soil measurably reduces movement of a tracer relative to the mobile water phase. The quantity of water infiltrating the soil, however, still follows from the product of the distance travelled by the tracer and average moisture content of the soil over that distance. Partitioning between surface and water phases in a soil by proton and protium exchange has only a small effect on the retention of isotopically labelled water. Partitioning between surface, water and gas phases in a soil, however, strongly decreases diffusive movement of isotopically labelled water in the gas phase. In sandy soils with moisture contents less than 5%, the effective diffusion coefficient in the gas phase can be reduced by a factor between 50 and 5000. As a soil dries out, diffusive movement of 18O labelled water will become larger than of HDO and HTO. Negative charges on soil surfaces repel chloride and bromide. The effect of charge exclusion on movement of Cl - and Br - relative to HDO was measured in small columns for a number of soils from the southwest of Western Australia. Data from these experiments show that in the unsaturated zone of sandy soils, charge exclusion can reduce the pore volume available to Cl - and Br - in the water phase at field capacity by > 20%. Recharge to ground water, if calculated from the position of Cl - or Br - tracers and average moisture in the soil profile, must then be reduced by the same percentage. The effect of charge exclusion in soils on the calculation of recharge from profile data, was evaluated for a practical situation. Significant amounts of bromide from car exhaust gases accumulate in soils in urban areas and can be used to trace water movement. A site was chosen in metropolitan Perth on a sparsely vegetated calcareous sand near the junction of two busy roads. A seasonal effect on bromide accumulation in the soil profile at this site was clearly visible from data on the soil solution

  3. PAH sorption mechanism and partitioning behavior in lampblack-impacted soils from former oil-gas plant sites.

    PubMed

    Hong, Lei; Ghosh, Upal; Mahajan, Tania; Zare, Richard N; Luthy, Richard G

    2003-08-15

    This study assessed polycyclic aromatic hydrocarbon (PAH) association and aqueous partitioning in lampblack-impacted field soils from five sites in California that formerly housed oil-gas process operations. Lampblack is the solid residue resulting from the decomposition of crude oil at high temperatures in the gas-making operation and is coated or impregnated with oil gasification byproducts, among which PAHs are the compounds of the greatest regulatory concern. A suite of complementary measurements investigated the character of lampblack particles and PAH location and the associated effects on PAH partitioning between lampblack and water. PAH analyses on both whole samples and density-separated components demonstrated that 81-100% of PAHs in the lampblack-impacted soils was associated with lampblack particles. FTIR, 13C NMR, and SEM analyses showed that oil-gas lampblack solids comprise primarily aromatic carbon with soot-like structures. A free-phase aromatic oil may be present in some of the lampblack soils containing high PAH concentrations. Comparable long-term aqueous partitioning measurements were obtained with an air-bridge technique and with a centrifugation/alum flocculation procedure. Large solid/water partition coefficient (Kd) values were observed in samples exhibiting lower PAH and oil levels, whereas smaller Kd values were measured in lampblack samples containing high PAH levels. The former result is in agreement with an oil-soot partitioning model, and the latter is in agreement with a coal tar-water partitioning model. Lampblack containing high PAH levels appears to exhaust the sorption capacity of the soot-carbon, creating a free aromatic oil phase that exhibits partitioning behavior similar to PAHs in coal tar. This study improves mechanistic understanding of PAH sorption on aged lampblack residuals at former oil-gas sites and provides a framework for mechanistic assessment of PAH leaching potential and risk from such site materials. PMID

  4. Modeling of crude oil biodegradation using two phase partitioning bioreactor.

    PubMed

    Fakhru'l-Razi, A; Peyda, Mazyar; Ab Karim Ghani, Wan Azlina Wan; Abidin, Zurina Zainal; Zakaria, Mohamad Pauzi; Moeini, Hassan

    2014-01-01

    In this work, crude oil biodegradation has been optimized in a solid-liquid two phase partitioning bioreactor (TPPB) by applying a response surface methodology based d-optimal design. Three key factors including phase ratio, substrate concentration in solid organic phase, and sodium chloride concentration in aqueous phase were taken as independent variables, while the efficiency of the biodegradation of absorbed crude oil on polymer beads was considered to be the dependent variable. Commercial thermoplastic polyurethane (Desmopan®) was used as the solid phase in the TPPB. The designed experiments were carried out batch wise using a mixed acclimatized bacterial consortium. Optimum combinations of key factors with a statistically significant cubic model were used to maximize biodegradation in the TPPB. The validity of the model was successfully verified by the good agreement between the model-predicted and experimental results. When applying the optimum parameters, gas chromatography-mass spectrometry showed a significant reduction in n-alkanes and low molecular weight polycyclic aromatic hydrocarbons. This consequently highlights the practical applicability of TPPB in crude oil biodegradation. PMID:24692323

  5. 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.

  6. Influence of colloids on sediment-water partition coefficients of polychlorobiphenyl congeners in natural waters

    SciTech Connect

    Baker, J.E.; Capel, P.D.; Eisenreich, S.J.

    1986-11-01

    Measurements of sediment-water partitioning of polychlorobiphenyl (PCB) congeners in Lake Superior provide some of the first field evidence demonstrating the importance of colloids to the fates of highly hydrophobic organic pollutants. Laboratory-derived correlations between sediment-water distribution coefficients and properties of both the contaminant (octanol-water partition coefficient) and the suspended solids (organic carbon content, concentration) do not accurately predict PCB speciation in Lake Superior. This failure can be explained by the presence of colloidal matter with which contaminants may associate and the very low solids concentrations in oligotrophic surface waters. A surprising consequence of such colloid associations is that the observed sediment-water distribution coefficients are independent of properties of highly hydrophobic compounds. A three-phase model including nonfilterable microparticles and macromolecular organic matter shows that colloidal-associated contaminants may be the dominant species in most surface waters. Colloidal associations are therefore likely to significantly impact the geochemistry of hydrophobic pollutants.

  7. 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

    2016-01-01

    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

  8. 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

  9. 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.

  10. Multi-A Graph Patrolling and Partitioning

    NASA Astrophysics Data System (ADS)

    Elor, Y.; Bruckstein, A. M.

    2012-12-01

    We introduce a novel multi agent patrolling algorithm inspired by the behavior of gas filled balloons. Very low capability ant-like agents are considered with the task of patrolling an unknown area modeled as a graph. While executing the proposed algorithm, the agents dynamically partition the graph between them using simple local interactions, every agent assuming the responsibility for patrolling his subgraph. Balanced graph partition is an emergent behavior due to the local interactions between the agents in the swarm. Extensive simulations on various graphs (environments) showed that the average time to reach a balanced partition is linear with the graph size. The simulations yielded a convincing argument for conjecturing that if the graph being patrolled contains a balanced partition, the agents will find it. However, we could not prove this. Nevertheless, we have proved that if a balanced partition is reached, the maximum time lag between two successive visits to any vertex using the proposed strategy is at most twice the optimal so the patrol quality is at least half the optimal. In case of weighted graphs the patrol quality is at least (1)/(2){lmin}/{lmax} of the optimal where lmax (lmin) is the longest (shortest) edge in the graph.

  11. 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...

  12. 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.

  13. Fourier transform spectrometer controller for partitioned architectures

    NASA Astrophysics Data System (ADS)

    Tamas-Selicean, D.; Keymeulen, D.; Berisford, D.; Carlson, R.; Hand, K.; Pop, P.; Wadsworth, W.; Levy, R.

    The current trend in spacecraft computing is to integrate applications of different criticality levels on the same platform using no separation. This approach increases the complexity of the development, verification and integration processes, with an impact on the whole system life cycle. Researchers at ESA and NASA advocated for the use of partitioned architecture to reduce this complexity. Partitioned architectures rely on platform mechanisms to provide robust temporal and spatial separation between applications. Such architectures have been successfully implemented in several industries, such as avionics and automotive. In this paper we investigate the challenges of developing and the benefits of integrating a scientific instrument, namely a Fourier Transform Spectrometer, in such a partitioned architecture.

  14. 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.

  15. Some comments on molecular partition functions

    SciTech Connect

    Sharp, C.M.

    1987-03-01

    In models of cool stellar atmospheres where molecules are important, molecular spectroscopic data can be used to calculate partition functions, from which equilibrium constants hence abundances can be obtained. In this report, it is shown that simple analytic approximations can be used to calculate very easily the partition functions of diatomic molecules, and comparisons are made for the two particularly important astrophysical molecules, H/sub 2/ and CO, with other work where the partition functions are calculated by explicitly summing over a very large number of energy levels. It is found that these analytic approximations give excellent agreement with more detailed calculations and are certainly adequate for many purposes. This method is very convenient, as only a few spectroscopic constants are needed, and the analytic formulae are very easily evaluated.

  16. Origins of Linear Partitioning in Binary Solutions: the Exchange Coefficient

    NASA Astrophysics Data System (ADS)

    Morse, S. A.

    2006-05-01

    Linear partitioning occurs when, as often in petrologic systems and perhaps always in azeotropes, a straight- line relationship occurs when the partition coefficient D = X1S/X1L is plotted against the solid composition X2S and runs from an intercept value KD at pure (2) to 1.0 at pure (1). The equation is then D = KD*X2S + X1S (Morse 1997, JGeol 105:471; 2000 GCA, 64:2309). The notation KD was taken from its long-standing familiarity in binary solutions (Roeder & Emslie 1970, CMP 29:275) and described as the exchange coefficient (Beattie et al. 1993 GCA 57:1605). But the binary loop is not in itself an exchange equilibrium; it is a transfer equilibrium marching to a different drummer, and that causes a problem (Kretz 2005, CanMin 43:1349). In at least three ways, the binary loop qualifies as an exchange reaction and justifies calling the intercept KD. To the experimentalist this issue never arises. In a perfect liquidus experiment, an infinitesimal mass of liquid is indeed transferred to the crystal. A second bulk composition is then made, and at the new liquidus a second mass transfer occurs. The ensemble of all such perfect partitioning experiments in sufficient number then completely delineates the binary loop without any continuous transfer at changing T having taken place. The partitionings are therefore truly independent of the path. Moreover, each equilibrium pair defines a common tangent in G-X space whose intercept at pure (2) unarguably gives the value of the common chemical potential, a partial Gibbs energy. But where is the exchange reaction? The real experimentalist makes no perfect experiments, and neither does nature. In reality, the barrier to nucleation (particularly formidable in the case of plagioclase) dictates that the crystals nucleate only at some supercooling. They therefore have some composition between the initial solidus and the liquid lying at the bulk composition (BC). Over time the two phases may drift apart by diffusion, the crystal

  17. DNA Partitioning in Confining Nanofluidic Slits

    NASA Astrophysics Data System (ADS)

    Greenier, Madeline; Levy, Stephen

    We measure the partitioning of double stranded DNA molecules in moderately and strongly confining nanofluidic slit-like structures. Using fluorescent microscopy, the free energy penalty of confinement is inferred by comparing the concentration of DNA molecules in adjoining slits of different depths. These depths range in size from several persistence lengths to the DNA molecule's radius of gyration. The partition coefficient is determined as a function of the slit depth, DNA contour length, and DNA topology. We compare our results to theory and Monte Carlo simulations that predict the loss of free energy for ideal and semiflexible excluded volume polymers confined between parallel plates.

  18. Partition signed social networks via clustering dynamics

    NASA Astrophysics Data System (ADS)

    Wu, Jianshe; Zhang, Long; Li, Yong; Jiao, Yang

    2016-02-01

    Inspired by the dynamics phenomenon occurred in social networks, the WJJLGS model is modified to imitate the clustering dynamics of signed social networks. Analyses show that the clustering dynamics of the model can be applied to partition signed social networks. Traditionally, blockmodel is applied to partition signed networks. In this paper, a detailed dynamics-based algorithm for signed social networks (DBAS) is presented. Simulations on several typical real-world and illustrative networks that have been analyzed by the blockmodel verify the correctness of the proposed algorithm. The efficiency of the algorithm is verified on large scale synthetic networks.

  19. 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.

  20. Gas/Aerosol partitioning: a simplified method for global modeling

    NASA Astrophysics Data System (ADS)

    Metzger, S. M.

    2000-09-01

    The main focus of this thesis is the development of a simplified method to routinely calculate gas/aerosol partitioning of multicomponent aerosols and aerosol associated water within global atmospheric chemistry and climate models. Atmospheric aerosols are usually multicomponent mixtures, partly composed of acids (e.g. H2SO4, HNO3), their salts (e.g. (NH4)2SO4, NH4NO3, respectively), and water. Because these acids and salts are highly hygroscopic, water, that is associated with aerosols in humid environments, often exceeds the total dry aerosol mass. Both the total dry aerosol mass and the aerosol associated water are important for the role of atmospheric aerosols in climate change simulations. Still, multicomponent aerosols are not yet routinely calculated within global atmospheric chemistry or climate models. The reason is that these particles, especially volatile aerosol compounds, require a complex and computationally expensive thermodynamical treatment. For instance, the aerosol associated water depends on the composition of the aerosol, which is determined by the gas/liquid/solid partitioning, in turn strongly dependent on temperature, relative humidity, and the presence of pre-existing aerosol particles. Based on thermodynamical relations such a simplified method has been derived. This method is based on the assumptions generally made by the modeling of multicomponent aerosols, but uses an alternative approach for the calculation of the aerosol activity and activity coefficients. This alternative approach relates activity coefficients to the ambient relative humidity, according to the vapor pressure reduction and the generalization of Raoult s law. This relationship, or simplification, is a consequence of the assumption that the aerosol composition and the aerosol associated water are in thermodynamic equilibrium with the ambient relative humidity, which determines the solute activity and, hence, activity coefficients of a multicomponent aerosol mixture

  1. Glycosylation-mediated phenylpropanoid partitioning in Populus tremuloides cell cultures

    PubMed Central

    2009-01-01

    Background Phenylpropanoid-derived phenolic glycosides (PGs) and condensed tannins (CTs) comprise large, multi-purpose non-structural carbon sinks in Populus. A negative correlation between PG and CT concentrations has been observed in several studies. However, the molecular mechanism underlying the relationship is not known. Results Populus cell cultures produce CTs but not PGs under normal conditions. Feeding salicyl alcohol resulted in accumulation of salicins, the simplest PG, in the cells, but not higher-order PGs. Salicin accrual reflected the stimulation of a glycosylation response which altered a number of metabolic activities. We utilized this suspension cell feeding system as a model for analyzing the possible role of glycosylation in regulating the metabolic competition between PG formation, CT synthesis and growth. Cells accumulated salicins in a dose-dependent manner following salicyl alcohol feeding. Higher feeding levels led to a decrease in cellular CT concentrations (at 5 or 10 mM), and a negative effect on cell growth (at 10 mM). The competition between salicin and CT formation was reciprocal, and depended on the metabolic status of the cells. We analyzed gene expression changes between controls and cells fed with 5 mM salicyl alcohol for 48 hr, a time point when salicin accumulation was near maximum and CT synthesis was reduced, with no effect on growth. Several stress-responsive genes were up-regulated, suggestive of a general stress response in the fed cells. Salicyl alcohol feeding also induced expression of genes associated with sucrose catabolism, glycolysis and the Krebs cycle. Transcript levels of phenylalanine ammonia lyase and most of the flavonoid pathway genes were reduced, consistent with down-regulated CT synthesis. Conclusions Exogenous salicyl alcohol was readily glycosylated in Populus cell cultures, a process that altered sugar utilization and phenolic partitioning in the cells. Using this system, we identified candidate genes

  2. Biomass Accumulation and Partitioning in Two Potato Cultivars as Influenced by Irrigation and Nitrogen Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The acreage under ‘Umatilla Russet’ and ‘Ranger Russet’ potato cultivars increased during the recent years in the Pacific Northwest (PNW). Research to determine the optimal management of fertilizer and water on the growth characteristics, yield, and yield attributes of these new cultivars are lackin...

  3. 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.

  4. 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

  5. Rigorous Definition of Oxidation States of Ions in Solids

    NASA Astrophysics Data System (ADS)

    Jiang, Lai; Levchenko, Sergey V.; Rappe, Andrew M.

    2012-04-01

    We present justification and a rigorous procedure for electron partitioning among atoms in extended systems. The method is based on wave-function topology and the modern theory of polarization, rather than charge density partitioning or wave-function projection, and, as such, reformulates the concept of oxidation state without assuming real-space charge transfer between atoms. This formulation provides rigorous electrostatics of finite-extent solids, including films and nanowires.

  6. Influence of carbon partitioning kinetics on final Austenite fraction during quenching and partitioning

    SciTech Connect

    Clarke, Amy J; Speer, John G; Matlock, David K; Rizzo, F C; Edmonds, David V; Santofimia, Maria J

    2009-01-01

    The quenching and partitioning (Q&P) process is a two-stage heat-treatment procedure proposed for producing steel microstructures that contain carbon-enriched retained austenite. In Q&P processing, austenite stabilization is accomplished by carbon partitioning from supersaturated martensite. A quench temperature selection methodology was developed to predict an optimum process quench temperature; extension of this methodology to include carbon partitioning kinetics is developed here. Final austenite fraction is less sensitive to quench temperature than previously predicted, in agreement with experimental results.

  7. Constraints on light noble gas partitioning at the conditions of spinel-peridotite melting

    NASA Astrophysics Data System (ADS)

    Jackson, Colin R. M.; Parman, Stephen W.; Kelley, Simon P.; Cooper, Reid F.

    2013-12-01

    Helium partitioning between olivine, orthopyroxene, clinopyroxene, and spinel and basaltic melt has been experimentally determined under upper mantle melting conditions (up to 20 kbar and 1450 °C). Under the conditions explored, helium partition coefficients are similar in all minerals investigated (KdHe˜10-4), suggesting He is evenly distributed between the minerals of spinel peridotite. This is in contrast to most incompatible elements, which are concentrated in clinopyroxene in spinel peridotite. The studied minerals have different concentrations of point defects, but similar He solubility, providing no evidence for He partitioning onto specific defects sites (e.g. cation vacancies). Upper limits on the partition coefficients for Ne and Ar have also been determined, constraining these elements to be moderately to highly incompatible in olivine at the conditions of spinel peridotite melting (<10-2 and <10-3, respectively). Helium partitioning in peridotite minerals varies little within the range of temperatures, pressures, and mineral compositions explored in this study. Reported partition coefficients, in combination with previous work, suggest that moderate to high degree mantle melting is not an efficient mechanism for increasing (U+Th)/He, (U+Th)/Ne, or K/Ar of the depleted mantle (DMM) through time, and consequently, supports the argument that recycling of oceanic crust is largely responsible for the relatively strong radiogenic noble gas signatures in the depleted mantle. Mantle residues with lowered (U+Th)/He, (U+Th)/Ne, and K/Ar may be produced through large extents of melting, but concentrations of noble gases will be low, unless noble gas solubility in solids deviate from Henry's Law at high fugacity.

  8. Cellulose Deficiency Is Enhanced on Hyper Accumulation of Sucrose by a H+-Coupled Sucrose Symporter.

    PubMed

    Yeats, Trevor H; Sorek, Hagit; Wemmer, David E; Somerville, Chris R

    2016-05-01

    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

  9. Carbon and Nitrogen Assimilation and Partitioning in Soybeans Exposed to Low Root Temperatures 1

    PubMed Central

    Walsh, Kerry B.; Layzell, David B.

    1986-01-01

    Low root temperature effects on vegetative growth of soybean (Harosoy 63 × Rhizobium japonicum USDA 16) were examined in 35 day old plants exposed to temperatures of 15°C (shoots at 25°C) for an 11 day period. Duing this period various aspects of C and N assimilation and partitioning were monitored including shoot night and nodulated root respiration, C and N partitioning to six plant parts, C2H2 reduction, H2 evolution, leaf area, transpiration, net photosynthesis, and N2 fixation. The low temperature treatment resulted in a decrease in the net rate of N2 fixation but nitrogenase relative efficiency increased. In response, the plant retained N in the tissues of the nodulated root and decreased N partitioning to young shoot tissues, thereby inducing the remobilization of N from older leaves, and reducing leaf area development. The leaf area specific rate of net photosynthesis was not affected over the study period; however, shoot and nodulated root respiration declined. Consequently, C accumulated in mature leaves and stems, partly in the form of increased starch reserves. Three possibilities were considered for increasing low temperature tolerance in nodulated soybeans: (a) decrease in temperature optima for nitrogenase, (b) increased development of nodules and N2 fixation capacity at low temperature, and (c) alterations in the pattern of C and N partitioning in response to low temperature conditions. PMID:16664592

  10. 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.

  11. PARTITIONING OF METALS IN ROTARY KILN INCINERATION

    EPA Science Inventory

    This research project investigated the fate of trace metals in rotary kiln incineration with venturi- and packed tower-scrubber particulate- and acid gas-control. est plan was developed, using a factorial experimental design, to study the partitioning of metals among kiln ash, sc...

  12. Lipid metabolism and nutrient partitioning strategies.

    PubMed

    Morris, A M; Calsbeek, D J; Eckel, R H

    2004-10-01

    The increasing prevalence of overweight and obesity worldwide is daunting and requires prompt attention by the affected, health care profession, government and the pharmaceutical industry. Because overweight/obesity are defined as an excess of adipose tissue mass, all approaches in prevention and treatment must consider redirecting lipid storage in adipose tissue to oxidative metabolism. Lipid partitioning is a complex process that involves interaction between fat and other macronutrients, particularly carbohydrate. In an isocaloric environment, when fat is stored carbohydrate is oxidized and vice versa. Processes that influence fat partitioning in a manner in which weight is maintained must be modified by changes in organ-specific fat transport and metabolism. When therapy is considered, however, changes in lipid partitioning alone will be ineffective unless a negative energy balance is also achieved, i.e. energy expenditure exceeds energy intake. The intent of this review is to focus on molecules including hormones, enzymes, cytokines, membrane transport proteins, and transcription factors directly involved in fat trafficking and partitioning that could be potential drug targets. Some examples of favorably altering body composition by systemic and/or tissue specific modification of these molecules have already been provided with gene knockout and/or transgenic approaches in mice. The translation of this science to humans remains a challenging task. PMID:15544448

  13. Hydrologic transport and partitioning of phosphorus fractions

    NASA Astrophysics Data System (ADS)

    Berretta, C.; Sansalone, J.

    2011-06-01

    SummaryPhosphorus (P) in rainfall-runoff partitions between dissolved and particulate matter (PM) bound phases. This study investigates the transport and partitioning of P to PM fractions in runoff from a landscaped and biogenically-loaded carpark in Gainesville, FL (GNV). Additionally, partitioning and concentration results are compared to a similarly-sized concrete-paved source area of a similar rainfall depth frequency distribution in Baton Rouge, LA (BTR), where in contrast vehicular traffic represents the main source of pollutants. Results illustrate that concentrations of P fractions (dissolved, suspended, settleable and sediment) for GNV are one to two orders of magnitude higher than BTR. Despite these differences the dissolved fraction ( f d) and partitioning coefficient ( K d) distributions are similar, illustrating that P is predominantly bound to PM fractions. Examining PM size fractions, specific capacity for P (PSC) indicates that the P concentration order is suspended > settleable > sediment for GNV, similarly to BTR. For GNV the dominant PM mass fraction is sediment (>75 μm), while the mass of P is distributed predominantly between sediment and suspended (<25 μm) fractions since these PM mass fractions dominated the settleable one. With respect to transport of PM and P fractions the predominance of events for both areas is mass-limited first-flush, although each fraction illustrated unique washoff parameters. However, while transport is predominantly mass-limited, the transport of each PM and P fraction is influenced by separate hydrologic parameters.

  14. 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…

  15. UNCERTAINTY IN SOURCE PARTITIONING USING STABLE ISOTOPES

    EPA Science Inventory

    Stable isotope analyses are often used to quantify the contribution of multiple sources to a mixture, such as proportions of food sources in an animal's diet, C3 vs. C4 plant inputs to soil organic carbon, etc. Linear mixing models can be used to partition two sources with a sin...

  16. 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...

  17. Measure-theoretic sensitivity via finite partitions

    NASA Astrophysics Data System (ADS)

    Li, Jian

    2016-07-01

    For every positive integer n≥slant 2 , we introduce the concept of measure-theoretic n-sensitivity for measure-theoretic dynamical systems via finite measurable partitions, and show that an ergodic system is measure-theoretically n-sensitive but not (n  +  1)-sensitive if and only if its maximal pattern entropy is log n .

  18. hydrogen partitioning between postperovskite and bridgmanite

    NASA Astrophysics Data System (ADS)

    Townsend, J. P.; Jacobsen, S. D.; Bina, C. R.; Tsuchiya, J.

    2015-12-01

    We present new results from first-principles calculations of phonon spectra of lower mantle phases of MgSiO3 bridgmanite (brg) and postperovskite (ppv) including hydrous defects, and alumino-hydrous defects. We compute the partition coefficient of hydrogen between ppv and brg for hydrous and alumino-hydrous compositions at D" pressures and temperatures from first-principles lattice dynamics simulations and free energy calculations computed under the quasiharmonic approximation. We find that for aluminum free hydrous conditions the hydrogen partition coefficient between ppv and brg ranges from 0.2-0.8 within D". However, in the presence of aluminum the aluminum-hydrogen partition coefficient between ppv and brg is approximately 1.5. In general for a given pressure, lower temperature increases the partitioning of hydrogen into ppv for the aluminous models, but not for the aluminum free models. Because aluminum is is expected to occur in both natural slab and mantle compositions this suggests aluminous-hydrous ppv may be a host for water in D".

  19. 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...

  20. Creep-fatigue analysis by Strainrange Partitioning

    NASA Technical Reports Server (NTRS)

    Manson, S. S.; Halford, G. R.; Hirschbere, M. H.

    1973-01-01

    Strainrange Partitioning provides unifying framework for characterizing high-temperature, low-cycle, creep-fatigue properties of metals and alloys. Method offers distinct advantage to designers of immediately providing reliable upper and lower bounds on cyclic life for any type of inelastic strain cycle that may be encountered in service.

  1. Uranium and rare earth partitioning in Synroc

    SciTech Connect

    Smith, K.L.; Lumpkin, G.R.; Blackford, M.G.

    1993-12-31

    Improved AEM techniques were used to investigate three Synrocs containing 10 wt% simulated HLW and a fourth sample with {approximately}18 wt% simulated HLW. One of the 10 wt% loaded Synrocs also contained an addition of 1.0 wt% Na{sub 2}O and another contained an addition of 2.0 wt% Fe{sub 2}O{sub 3}. This work is part of a larger study initiated with the objective of determining if the bulk composition of Synroc affects the partitioning of elements between individual phases. Results from the four samples in this study show that, as expected, elemental partitioning is mainly controlled by the ionic radius criterion, with smaller Y, Gd, and U ions having a preference for zirconolite and the larger Ce and Nd ions favouring perovskite. Additions of Na and Fe lead to the formation of CAT and loveringite at the expense of rutile or Magneli phases, but only have minor effects on partitioning coefficients. Partitioning coefficients, D{sup Z/P}, for REE, Y, and U in the four Synrocs are the same (within experimental error).

  2. Partition function of interacting calorons ensemble

    NASA Astrophysics Data System (ADS)

    Deldar, S.; Kiamari, M.

    2016-01-01

    We present a method for computing the partition function of a caloron ensemble taking into account the interaction of calorons. We focus on caloron-Dirac string interaction and show that the metric that Diakonov and Petrov offered, works well in the limit where this interaction occurs. We suggest computing the correlation function of two polyakov loops by applying Ewald's method.

  3. 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...

  4. Further insight into the mechanism of heavy metals partitioning in stormwater runoff.

    PubMed

    Djukić, Aleksandar; Lekić, Branislava; Rajaković-Ognjanović, Vladana; Veljović, Djordje; Vulić, Tatjana; Djolić, Maja; Naunovic, Zorana; Despotović, Jovan; Prodanović, Dušan

    2016-03-01

    Various particles and materials, including pollutants, deposited on urban surfaces are washed off by stormwater runoff during rain events. The interactions between the solid and dissolved compounds in stormwater runoff are phenomena of importance for the selection and improvement of optimal stormwater management practices aimed at minimizing pollutant input to receiving waters. The objective of this research was to further investigate the mechanisms responsible for the partitioning of heavy metals (HM) between the solid and liquid phases in urban stormwater runoff. The research involved the collection of samples from urban asphalt surfaces, chemical characterization of the bulk liquid samples, solids separation, particle size distribution fractionation and chemical and physico-chemical characterization of the solid phase particles. The results revealed that a negligible fraction of HM was present in the liquid phase (less than 3% by weight), while there was a strong correlation between the total content of heavy metals and total suspended solids. Examinations of surface morphology and mineralogy revealed that the solid phase particles consist predominantly of natural macroporous materials: alpha quartz (80%), magnetite (11.4%) and silicon diphosphate (8.9%). These materials have a low surface area and do not have significant adsorptive capacity. These materials have a low surface area and do not have significant adsorptive capacity. The presence of HM on the surface of solid particles was not confirmed by scanning electron microscopy and energy dispersive X-ray microanalyses. These findings, along with the results of the liquid phase sample characterization, indicate that the partitioning of HM between the liquid and solid phases in the analyzed samples may be attributed to precipitation processes. PMID:26699454

  5. 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.

  6. 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...

  7. 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. PMID:25988579

  8. Equilibrium partition ratios, densities, and transport phenomena in nickel-base superalloys

    NASA Astrophysics Data System (ADS)

    Sung, Pil Kyung

    To simulate transport phenomena, macrosegregation and segregation defects known as "freckles" during directional solidification of Ni-base superalloys, numerical modeling can be used; hence it is essential to have reasonably accurate values of the thermodynamic and transport properties for the alloys. In this research, therefore, the equilibrium partition ratios of the solutes in the Ni-Al-Ta-Cr quaternary system, as a model alloy, were measured, and the solid- and liquid-densities in Ni-base superalloys. were estimated. Also, the importance of these properties on the sensitivity of the results of numerical simulations was studied. The partition ratios apply to equilibria between melts and gamma-phase in the range of 1615 K to 1694 K, and it was found that the equilibrium partition ratio of Ta varies from approximately 0.6 at dilute Ta to 0.85 at 17 wt.% Ta. For the same range of Ta-contents, the partition ratios of Al and Cr vary much less and range from about 0.92 to 0.96. In addition to the partition ratios, the liquidus temperatures of the liquid in equilibrium with gamma in the Ni-Al-Ta-Cr system were estimated with a multidimensional regression analysis. To calculate the densities of solid Ni-base superalloys as functions of temperature and composition, lattice parameters at 20°C and coefficients of thermal expansion (CTEs) were estimated by combining available data. The CTEs calculated from the regressions result in densities that are within 0.5% error or less for seventeen alloys. To estimate the densities of liquid Ni-base superalloys, the densities and temperature coefficients of density of the liquid transition-metals, which are used as alloy elements in Ni-base superalloys, were applied to a simple correlation. By using this approach, the estimates of the liquid densities of five Ni-base superalloys agree with the measured values to +/-2.5%. Finally, the importance of using reasonably accurate estimates of the transport properties was illustrated by

  9. Optimising query execution time in LHCb Bookkeeping System using partition pruning and Partition-Wise joins

    NASA Astrophysics Data System (ADS)

    Mathe, Zoltan; Charpentier, Philippe

    2014-06-01

    The LHCb experiment produces a huge amount of data which has associated metadata such as run number, data taking condition (detector status when the data was taken), simulation condition, etc. The data are stored in files, replicated on the Computing Grid around the world. The LHCb Bookkeeping System provides methods for retrieving datasets based on their metadata. The metadata is stored in a hybrid database model, which is a mixture of Relational and Hierarchical database models and is based on the Oracle Relational Database Management System (RDBMS). The database access has to be reliable and fast. In order to achieve a high timing performance, the tables are partitioned and the queries are executed in parallel. When we store large amounts of data the partition pruning is essential for database performance, because it reduces the amount of data retrieved from the disk and optimises the resource utilisation. This research presented here is focusing on the extended composite partitioning strategy such as range-hash partition, partition pruning and usage of the Partition-Wise joins. The system has to serve thousands of queries per minute, the performance and capability of the system is measured when the above performance optimization techniques are used.

  10. 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.

  11. Partitioning of heavy metals in a soil contaminated by slag: A redistribution study

    SciTech Connect

    Bunzl, K.; Trautmannsheimer, M.; Schramel, P.

    1999-08-01

    In order to interpret reasonably the partitioning of heavy metals in a contaminated soil as observed from applying a sequential extraction procedure, information on possible redistribution processes of the metals during the various extraction steps is essential. For this purpose, sequential extraction was used to study the chemical partitioning of Ag, Cu, Ni, Pb, and Zn in a soil contaminated wither by a slag from coal firing or by a slag from pyrite roasting. Through additional application of sequential extraction to the pure slags as well as to the uncontaminated soil, it was shown that during the various extraction steps applied to the soil/slag mixtures, substantial redistribution processes of the metals between the slag- and soil particles can occur. In many cases, metals ions released during the extraction with acid hydroxylamine or acid hydrogen peroxide are partially readsorbed by solid constituents of the mixture and will therefore be found in the subsequent fractions extracted. As a result, one has to realize that (1) it will be difficult to predict the chemical partitioning of these metals in contaminated soils by investigating pure slags only, and (2) information on the partitioning of a metal in a slag contaminated soil will not necessarily give any relevant information on the form of this metal in the slag or in the slag/soil mixture, because the redistribution processes during sequential extraction will not be the same as those occurring in the soil solution under natural conditions.

  12. 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.

  13. Vanadium Partitioning Among Phases Relevant to Eucrite Petrogenesis

    NASA Astrophysics Data System (ADS)

    Hanson, B. Z.; Jones, J. H.; Mittlefehldt, D. W.; Jurewicz, A. J. G.

    1995-09-01

    Scandium, V, and Cr are depleted in eucrites compared to other lithophile refractory trace elements, and, therefore, understanding these depletions is important to deciphering the origin of eucrites. Previously, we have reported Sc partitioning experiments relevant to eucrite petrogenesis [1] and V concentrations in partial melts of the Murchison chondrite [2]. The Sc experiments indicated that eucrites such as Sioux County were generated by about 20% partial melting of a source whose residual phases were dominated by olivine. Additionally, our V analyses of the Murchison glasses were very similar to those measured for the Sioux County eucrite. This was particularly gratifying, since the major element concentrations of our 1180 degrees C Murchison glass were also very similar to those of eucrites [3]. Because the solid residua of the Murchison experiments were also dominated by olivine, there was apparent qualitative agreement between the inferences from both Sc and V. Previously, Sc partition coefficients for olivine and pyroxene at 1190-1200 degrees C have allowed us to model eucrite petrogenesis by assuming that eucrites such as Sioux County are simple partial melts [1]. Newly acquired V partition coefficients (Table 1) allow us to perform a similar calculation for V (Table 2). Vanadium analyses were corrected for Ti interference, and the similarity of partition coefficients from different experiments gives us confidence in the results. In addition, lnD versus 1/T regressions give good fits with r^2 > 0.99. Thus, partial melting models may be tested, using our experimental partition coefficients, by independently modeling Sc and V depletions. The assumptions necessary may be summarized: Eucrites such as Sioux County are produced by equilibrium partial melting of a source region and this source has approximately CM chondrite relative abundances of refractory lithophile elements. With this proviso, we have a system of four equations and four unknowns: one equation

  14. 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.

  15. 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

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  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 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. THE ACCUMULATION AND RELEASE OF ARSENIC FROM DISTRIBUTION SYSTEM SOLIDS

    EPA Science Inventory

    The recently promulgated Arsenic Rule will require that many new drinking water systems treat their water to remove arsenic. Iron based treatment technologies including iron removal and iron coagulation are effective at reducing arsenic in water because iron surfaces have a stron...

  19. THE ACCUMULATION AND RELEASE OF CONTAMINANTS FROM DISTRIBUTION SYSTEM SOLIDS

    EPA Science Inventory

    The recently promulgated Arsenic Rule will require that many new drinking water systems treat their water to remove arsenic. Iron based treatment technologies including iron removal and iron coagulation are effective at reducing arsenic in water because iron surfaces have a stron...

  20. Uptake and partitioning of zinc in Lemnaceae.

    PubMed

    Lahive, Elma; O'Callaghan, Michael J A; Jansen, Marcel A K; O'Halloran, John

    2011-11-01

    Macrophytes provide food and shelter for aquatic invertebrates and fish, while also acting as reservoirs for nutrients and trace elements. Zinc accumulation has been reported for various Lemnaceae species. However, comparative accumulation across species and the link between zinc accumulation and toxicity are poorly understood. Morphological distribution and cellular storage, in either bound or soluble form, are important for zinc tolerance. This study shows differences in the uptake and accumulation of zinc by three duckweed species. Landoltia punctata and Lemna minor generally accumulated more zinc than Lemna gibba. L. minor, but not L. gibba or L. punctata, accumulated greater concentrations of zinc in roots compared to fronds when exposed to high levels of zinc. The proportion of zinc stored in the bound form relative to the soluble-form was higher in L. minor. L. punctata accumulated greater concentrations of zinc in fronds compared to roots and increased the proportion of zinc it stored in the soluble form, when exposed to high zinc levels. L. gibba is the only species that significantly accumulated zinc at low concentrations, and was zinc-sensitive. Overall, internal zinc concentrations showed no consistent correlation with toxic effect. We conclude that relationships between zinc toxicity and uptake and accumulation are species specific reflecting, among others, zinc distribution and storage. Differences in zinc distribution and storage are also likely to have implications for zinc bioavailability and trophic mobility. PMID:21755349

  1. 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.

  2. Kaposi's Sarcoma-Associated Herpesvirus Genome Replication, Partitioning, and Maintenance in Latency.

    PubMed

    Ohsaki, Eriko; Ueda, Keiji

    2012-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is thought to be an oncogenic member of the γ-herpesvirus subfamily. The virus usually establishes latency upon infection as a default infection pattern. The viral genome replicates according to the host cell cycle by recruiting the host cellular replication machinery. Among the latently expressing viral factors, LANA plays pivotal roles in viral genome replication, partitioning, and maintenance. LANA binds with two LANA-binding sites (LBS1/2) within a terminal repeat (TR) sequence and is indispensable for viral genome replication in latency. The nuclear matrix region seems to be important as a replication site, since LANA as well as cellular replication factors accumulate there and recruit the viral replication origin in latency (ori-P) by its binding activity to LBS. KSHV ori-P consists of LBS followed by a 32-bp GC-rich segment (32GC). Although it has been reported that LANA recruits cellular pre-replication complexes (pre-RC) such as origin recognition complexes (ORCs) to the ori-P through its interaction with ORCs, this mechanism does not account completely for the requirement of the 32GC. On the other hand, there are few reports about the partitioning and maintenance of the viral genome. LANA interacts with many kinds of chromosomal proteins, including Brd2/RING3, core histones, such as H2A/H2B and histone H1, and so on. The detailed molecular mechanisms by which LANA enables KSHV genome partitioning and maintenance still remain obscure. By integrating the findings reported thus far on KSHV genome replication, partitioning, and maintenance in latency, we will summarize what we know now, discuss what questions remain to be answered, and determine what needs to be done next to understand the mechanisms underlying viral replication, partitioning, and maintenance strategy. PMID:22291692

  3. Non-linear feedbacks between climate change, hydrologic partitioning, plant available water, and carbon cycling in montane forests

    NASA Astrophysics Data System (ADS)

    Brooks, P. D.; Litvak, M. E.; Harpold, A. A.; Molotch, N. P.; McIntosh, J. C.; Troch, P. A.; Zapata, X.

    2011-12-01

    Changes in both temperature and the amount and timing of precipitation have the potential to profoundly impact water balance in mountain ecosystems. Although changes in the amount of precipitation and potential evapotranspiration are widely considered in climate change scenarios, less attention has been given to how changes in climate or land cover may affect hydrologic partitioning and plant available water. The focus of this presentation is on how spatial transitions in ecosystem structure and temporal transitions in climate affect the fraction of precipitation potentially available to vegetation. In most temperate mountain environments winter snows are a significant fraction of annual precipitation and understanding the partitioning of snow and snow melt is critical for predicting both ecosystem water availability and stream flow under future climate scenarios. Spatial variability in net snow water input is a function of the interaction of snowfall, wind, and solar radiation with topography and vegetation structure. Integrated over larger scales these interactions may result in between 0% and 40% sublimation of winter snowfall before melt, effectively excluding this water from growing season water balance. Once melt begins, variability in the partitioning of snowmelt is driven by the rate of melt, and somewhat less intuitively, by the timing of snow accumulation the previous fall. Early accumulating snowpacks insulate soils and minimize soil frost increasing infiltration of melt the following spring. In contrast, later snowfall results in colder soils, more soil frost, reduced infiltration, increased runoff during melt, and reduced plant available water during the following growing season. This change in hydrologic partitioning, mediated by the timing of snowpack accumulation, results in lower evapotranspiration (ET) and net ecosystem exchange (NEE) the following spring. These findings suggest that abiotic controls on the partitioning of precipitation may

  4. 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.

  5. Partition coefficients of three new anticonvulsants.

    PubMed

    Hernandez-Gallegos, Z; Lehmann, P A

    1990-11-01

    The partition coefficients of three homologous anticonvulsant phenylalkylamides [racemic alpha-hydroxy-alpha-ethyl-alpha-phenylacetamide (HEPA); beta-hydroxy-beta-ethyl-beta-phenylpropionamide (HEPP); and gamma-hydroxy-gamma-ethyl-gamma-phenylbutyramide (HEPB)] were determined by reversed-phase high-performance liquid chromatography (RP-HPLC). The system was calibrated with a series of simple amines and amides, using their published log P values. The log kw values (methanol:water, extrapolated to 100% water) were 1.260 for HEPA, 1.670 for HEPP, and 1.852 for HEPB. From these results, the partition coefficients (log P) were calculated by regression as 1.20, 1.83, and 2.11, respectively. The log P values were essentially equal to those calculated by the Leo-Hansch fragmental method. Since the potency of the three anticonvulsants is approximately the same in a variety of tests, no dependence on lipophilicity could be established. PMID:2292764

  6. 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.

  7. 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.

  8. Rotational partition functions for linear molecules

    NASA Astrophysics Data System (ADS)

    McDowell, Robin S.

    1988-01-01

    An accurate closed-form expression for the rotational partition function of linear polyatomic molecules in 1Sigma electronic states is derived, including the effect of nuclear spin (significant at very low temperatures) and of quartic and sextic centrifugal distortion terms (significant at moderate and high temperatures). The proper first-order quantum correction to the classical rigid-rotator partition function is shown to yield Qr = about 1/beta exp beta/3, where beta is defined as hcB / kT and B is the rotational constant in per cm; for beta of 0.2 or greater additional power-series terms in beta are necessary. Comparison between the results of this treatment and exact summations are made for HCN and C2H2 at temperatures from 2 to 5000 K, including separate evaluation of the conributions of nuclear spin and centrifugal distortion.

  9. Mantle Mineral/Silicate Melt Partitioning

    NASA Astrophysics Data System (ADS)

    McFarlane, E. A.; Drake, M. J.

    1992-07-01

    Introduction: The partitioning of elements among mantle phases and silicate melts is of interest in unraveling the early thermal history of the Earth. It has been proposed that the elevated Mg/Si ratio of the upper mantle of the Earth is a consequence of the flotation of olivine into the upper mantle (Agee and Walker, 1988). Agee and Walker (1988) have generated a model via mass balance by assuming average mineral compositions to generate upper mantle peridotite. This model determines that upper mantle peridotite could result from the addition of 32.7% olivine and 0.9% majorite garnet into the upper mantle, and subtraction of 27.6% perovskite from the upper mantle (Agee and Walker, 1988). The present contribution uses experimental data to examine the consequences of such multiple phase fractionations enabling an independent evaluation of the above mentioned model. Here we use Mg-perovskite/melt partition coefficients from both a synthetic and a natural system (KLB-1) obtained from this laboratory. Also used are partition coefficient values for majorite garnet/melt, beta spinel/melt and olivine/melt partitioning (McFarlane et al., 1991b; McFarlane et al., 1992). Multiple phase fractionations are examined using the equilibrium crystallization equation and partition coefficient values. The mineral proportions determined by Agee and Walker (1988) are converted into weight fractions and used to compute a bulk partition coefficient value. Discussion: There has been a significant debate concerning whether measured values of trace element partition coefficients permit large-scale fractionation of liquidus phases from an early terrestrial magma ocean (Kato et al., 1988a,b; Walker and Agee, 1989; Drake, 1989; Drake et al., 1991; McFarlane et al., 1990, 1991). It should be noted that it is unclear which, if any, numerical values of partition coefficients are appropriate for examining this question, and certainly the assumptions for the current model must be more fully

  10. Grid-based partitioning for comparing attractors

    NASA Astrophysics Data System (ADS)

    Carroll, T. L.; Byers, J. M.

    2016-04-01

    Stationary dynamical systems have invariant measures (or densities) that are characteristic of the particular dynamical system. We develop a method to characterize this density by partitioning the attractor into the smallest regions in phase space that contain information about the structure of the attractor. To accomplish this, we develop a statistic that tells us if we get more information about our data by dividing a set of data points into partitions rather than just lumping all the points together. We use this method to show that not only can we detect small changes in an attractor from a circuit experiment, but we can also distinguish between a large set of numerically generated chaotic attractors designed by Sprott. These comparisons are not limited to chaotic attractors—they should work for signals from any finite-dimensional dynamical system.

  11. 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.

  12. 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.

  13. GPS/INS integration by functional partitioning

    NASA Astrophysics Data System (ADS)

    Diesel, John W.

    It is shown that a GPS/INS system integrated by functional partitioning can satisfy all of the RTCA navigation requirements and goals. This is accomplished by accurately calibrating the INS using GPS after the inertial instruments are thermally stabilized and by exploiting the very slow subsequent error growth in the INS information. In this way, autonomous integrity monitoring can be achieved using only existing or presently planned systems.

  14. Pure Partition Functions of Multiple SLEs

    NASA Astrophysics Data System (ADS)

    Kytölä, Kalle; Peltola, Eveliina

    2016-05-01

    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.

  15. Partitioning networks into communities by message passing.

    PubMed

    Lai, Darong; Nardini, Christine; Lu, Hongtao

    2011-01-01

    Community structures are found to exist ubiquitously in a number of systems conveniently represented as complex networks. Partitioning networks into communities is thus important and crucial to both capture and simplify these systems' complexity. The prevalent and standard approach to meet this goal is related to the maximization of a quality function, modularity, which measures the goodness of a partition of a network into communities. However, it has recently been found that modularity maximization suffers from a resolution limit, which prevents its effectiveness and range of applications. Even when neglecting the resolution limit, methods designed for detecting communities in undirected networks cannot always be easily extended, and even less directly applied, to directed networks (for which specifically designed community detection methods are very limited). Furthermore, real-world networks are frequently found to possess hierarchical structure and the problem of revealing such type of structure is far from being addressed. In this paper, we propose a scheme that partitions networks into communities by electing community leaders via message passing between nodes. Using random walk on networks, this scheme derives an effective similarity measure between nodes, which is closely related to community memberships of nodes. Importantly, this approach can be applied to a very broad range of networks types. In fact, the successful validation of the proposed scheme on real and synthetic networks shows that this approach can effectively (i) address the problem of resolution limit and (ii) find communities in both directed and undirected networks within a unified framework, including revealing multiple levels of robust community partitions. PMID:21405752

  16. Scheduling and process migration in partitioned multiprocessors

    SciTech Connect

    Gait, J. )

    1990-03-01

    A partitioned multiprocessor (PM) has a shared global bus and nonshared local memories. This paper studies a process scheduler, called the two-tier scheduler (TTS), for a PM. In a PM local scheduling amortizes the cost of loading processes in local memory. Global scheduling migrates processes to balance load. A tunable time quantum is adjusted so the average process completes execution on the processor on which it is first scheduled, and only relatively long lived processes are rescheduled globally.

  17. Phase partitioning in space and on earth

    NASA Technical Reports Server (NTRS)

    Van Alstine, James M.; Karr, Laurel J.; Snyder, Robert S.; Matsos, Helen C.; Curreri, Peter A.; Harris, J. Milton; Bamberger, Stephan B.; Boyce, John; Brooks, Donald E.

    1987-01-01

    The influence of gravity on the efficiency and quality of the impressive separations achievable by bioparticle partitioning is investigated by demixing polymer phase systems in microgravity. The study involves the neutral polymers dextran and polyethylene glycol, which form a two-phase system in aqueous solution at low concentrations. It is found that demixing in low-gravity occurs primarily by coalescence, whereas on earth the demixing occurs because of density differences between the phases.

  18. 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.

  19. Diversity partitioning during the Cambrian radiation.

    PubMed

    Na, Lin; Kiessling, Wolfgang

    2015-04-14

    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

  20. 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

  1. 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

  2. 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.

  3. Differntial cadmium accumulation and phytotoxicity in sixteen tobacco cultivars

    SciTech Connect

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

    1988-01-01

    Contrary to most agronomic plants, tobacco accumulates a greater proportion of cadmium (Cd) in its foliage than in any other plant part when it is exposed to Cd-contaminated soil or sand. Because tobacco leaves are marketed as a commercial product, this pattern of partitioning is highly undesirable from the standpoint of human toxicity. Recognizing that Cd uptake and translocation is under genetic control, the authors evaluated the distribution of cadmium in 16 tobacco cultivars to determine whether a genotype could be selected that minimizes the accumulation of Cd in the leaf. In order to assess the impact of low levels of cadmium that might originate from superphosphate, fertilizers, sludge, or contaminated rain on plant growth, several growth parameters of Cd-treated and untreated tobacco plants were compared. The results of these studies are presented.

  4. 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

    2016-06-01

    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. PMID:27115830

  5. 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.

  6. Partitioning and matrix-specific toxicity of bifenthrin among sediments and leaf-sourced organic matter.

    PubMed

    Maul, Jonathan D; Trimble, Andrew J; Lydy, Michael J

    2008-04-01

    Synthetic pyrethroids readily partition from the aqueous to the solid phase in aquatic systems. Previous work has focused on pyrethroid partitioning to sediment matrices. Within many aquatic systems, however, other carbon-containing materials are present and can be critically important to certain invertebrate species and ecosystem functioning. For example, some invertebrates readily process leaf material, and these processes may represent an additional route of contaminant exposure. To our knowledge, estimates for partitioning of pyrethroids to these nondissolved organic matter matrices and associated toxicity have not been examined. The objectives of the present study were to examine variation in organic carbon (OC)-based partition coefficient (K(OC)) among three size fractions of particulate organic matter from sugar maple (Acer saccharum) leaf litter and sediments for the pyrethroid insecticide bifenthrin and to examine variation in toxicity to Hyalella azteca among bifenthrin-bound organic matter matrices and sediment. Log K(OC) of [(14)C]bifenthrin was greatest within sediment (6.63+/-0.23; mean +/- standard deviation throughout) and lowest in coarse particulate leaf material (4.86+/-0.03). The H. azteca median lethal concentration was 0.07, 0.11, and 0.15 microg/g OC for leaf material, sediment, and a 50% mix of leaf and sediment, respectively. Nonoverlapping 95% confidence intervals occurred between the leaf treatment and the leaf-sediment treatment. This pattern was supported in an additional experiment, and at 0.22 microg/g OC, H. azteca survival was greater in the leaf-sediment mixture than in sediment or in leaf material alone (F=29.5, p<0.0001). In systems that contain sediment and leaf material, both greater partitioning of bifenthrin to the sediment fraction and preferential use of leaf substrates may drive H. azteca survival. PMID:18333691

  7. 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.

  8. Kinetic quantification of vertical solid matter transfers in soils by a multi-tracers approach

    NASA Astrophysics Data System (ADS)

    Jagercikova, Mariannaa; Cornu, Sophiea; Bourl`es, Didierb; Evrard, Olivierc; Alainb, V.'eron; Hatt'e, Christinec; Ayrault, Sophiec; Jérômea, Balesdent

    2015-04-01

    We will present a novel multi-tracers method - combining different isotopic systems (137 Cs, 210 Pb (xs), meteoric 10 Be, 206/207 Pb, δ13 C, 14 C) with numerical modeling based on a non-linear diffusion-convection equation with depth dependent parameters - to quantify vertical transfer of solid matter in Luvisols, namely clay translocation and bioturbation. Our results show that as much as 91 ± 9 % and 80 ± 9 % of 137Cs and 10Be, respectively, are associated with the clay size fraction (0-2 µm) and provide therefore relevant tracers to investigate vertical transfer of solid matter in soils with pH > 5 and low organic carbon contents. Lead partitioning between different solid phases is more complex. Considering two spatial distributions of isotopes (macropores or soil matrix) depending on the contribution of a fraction inherited from the loess parent material to the soil concentration, we built up a multi-tracers modeling approach that simulates the experimental data with the common set of transfer parameters and allows us to quantify the relative contributions of vertical solid matter transfers to present-day 0-2 µm vertical distributions. Clay translocation is responsible for 9 to 66 % of clay accumulation in the Bt-horizon. The diffusion coefficients quantifying the rate of soil mixing by bioturbation yields values that are significantly higher than those estimated in previous ecological studies. Modeling the kinetics of solid matter transfer at various spatial and temporal scales should become a reference method in modern pedogenic and critical zone studies.

  9. Himalayan Strain Accumulation 100 ka Timescales

    NASA Astrophysics Data System (ADS)

    Cannon, J. M.; Murphy, M. A.; Liu, Y.

    2015-12-01

    Crustal scale fault systems and tectonostratigraphic units in the Himalaya can be traced for 2500 km along strike. However regional studies have shown that there is variability in the location and rate of strain accumulation which appears to be driven by Main Himalayan Thrust (MHT) geometry and convergence obliquity. GPS illuminates the modern interseismic strain rate and the historical record of great earthquakes elucidates variations in strain accumulation over 103 years. To connect these patterns with the 106 year structural and thermochronometric geologic record we examine normalized river channel steepness (ksn), a proxy for rock uplift rate, which develops over 104 - 105 years. Here we present a ksn map of the Himalaya and compare it with bedrock geology, precipitation, the historic earthquake record, GPS, seismicity, and seismotectonic models. Our map shows significant along strike changes in the magnitude of channel steepness, the areal extent of swaths of high ksn channels, and their location with respect to the range front. Differences include the juxtaposition of two narrow (30 - 40 km) range parallel belts of high ksn in west Nepal and Bhutan coincident with MHT duplexes and belts of microseismcity, with a single broad (70 km) swath of high ksn and microseismicity in central and eastern Nepal. Separating west and central Nepal a band of low ksn crosses the range coincident with the West Nepal Fault (WNF) and the lowest rate of microseismicity in Nepal. To the west the orogen is obliquely convergent and has less high ksn channels, while the orthogonally convergent region to the east contains the highest concentration of oversteepened channels in the Himalaya supporting the idea that the WNF is a strain partitioning boundary. The syntaxes are characterized by locally high channel steepness surrounded by low to moderate ksn channels consistent with the hypothesis that rapid exhumation within the syntaxes is sustained by an influx of lower crust.

  10. ITER helium ash accumulation

    SciTech Connect

    Hogan, J.T.; Hillis, D.L.; Galambos, J.; Uckan, N.A. ); Dippel, K.H.; Finken, K.H. . Inst. fuer Plasmaphysik); Hulse, R.A.; Budny, R.V. . Plasma Physics Lab.)

    1990-01-01

    Many studies have shown the importance of the ratio {upsilon}{sub He}/{upsilon}{sub E} in determining the level of He ash accumulation in future reactor systems. Results of the first tokamak He removal experiments have been analysed, and a first estimate of the ratio {upsilon}{sub He}/{upsilon}{sub E} to be expected for future reactor systems has been made. The experiments were carried out for neutral beam heated plasmas in the TEXTOR tokamak, at KFA/Julich. Helium was injected both as a short puff and continuously, and subsequently extracted with the Advanced Limiter Test-II pump limiter. The rate at which the He density decays has been determined with absolutely calibrated charge exchange spectroscopy, and compared with theoretical models, using the Multiple Impurity Species Transport (MIST) code. An analysis of energy confinement has been made with PPPL TRANSP code, to distinguish beam from thermal confinement, especially for low density cases. The ALT-II pump limiter system is found to exhaust the He with maximum exhaust efficiency (8 pumps) of {approximately}8%. We find 1<{upsilon}{sub He}/{upsilon}{sub E}<3.3 for the database of cases analysed to date. Analysis with the ITER TETRA systems code shows that these values would be adequate to achieve the required He concentration with the present ITER divertor He extraction system.

  11. Kinetic model of sucrose accumulation in maturing sugarcane culm tissue.

    PubMed

    Uys, Lafras; Botha, Frederik C; Hofmeyr, Jan-Hendrik S; Rohwer, Johann M

    2007-01-01

    Biochemically, it is not completely understood why or how commercial varieties of sugarcane (Saccharum officinarum) are able to accumulate sucrose in high concentrations. Such concentrations are obtained despite the presence of sucrose synthesis/breakdown cycles (futile cycling) in the culm of the storage parenchyma. Given the complexity of the process, kinetic modelling may help to elucidate the factors governing sucrose accumulation or direct the design of experimental optimisation strategies. This paper describes the extension of an existing model of sucrose accumulation (Rohwer, J.M., Botha, F.C., 2001. Analysis of sucrose accumulation in the sugar cane culm on the basis of in vitro kinetic data. Biochem. J. 358, 437-445) to account for isoforms of sucrose synthase and fructokinase, carbon partitioning towards fibre formation, and the glycolytic enzymes phosphofructokinase (PFK), pyrophosphate-dependent PFK and aldolase. Moreover, by including data on the maximal activity of the enzymes as measured in different internodes, a growth model was constructed that describes the metabolic behaviour as sugarcane parenchymal tissue matures from internodes 3-10. While there was some discrepancy between modelled and experimentally determined steady-state sucrose concentrations in the cytoplasm, steady-state fluxes showed a better fit. The model supports a hypothesis of vacuolar sucrose accumulation against a concentration gradient. A detailed metabolic control analysis of sucrose synthase showed that each isoform has a unique control profile. Fructose uptake by the cell and sucrose uptake by the vacuole had a negative control on the futile cycling of sucrose and a positive control on sucrose accumulation, while the control profile for neutral invertase was reversed. When the activities of these three enzymes were changed from their reference values, the effects on futile cycling and sucrose accumulation were amplified. The model can be run online at the JWS Online

  12. 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.

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

    PubMed

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

    2016-02-01

    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

  14. 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

  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. 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.

  17. 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.

  18. 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.

  19. A Partitioning Algorithm for Block-Diagonal Matrices With Overlap

    SciTech Connect

    Guy Antoine Atenekeng Kahou; Laura Grigori; Masha Sosonkina

    2008-02-02

    We present a graph partitioning algorithm that aims at partitioning a sparse matrix into a block-diagonal form, such that any two consecutive blocks overlap. We denote this form of the matrix as the overlapped block-diagonal matrix. The partitioned matrix is suitable for applying the explicit formulation of Multiplicative Schwarz preconditioner (EFMS) described in [3]. The graph partitioning algorithm partitions the graph of the input matrix into K partitions, such that every partition {Omega}{sub i} has at most two neighbors {Omega}{sub i-1} and {Omega}{sub i+1}. First, an ordering algorithm, such as the reverse Cuthill-McKee algorithm, that reduces the matrix profile is performed. An initial overlapped block-diagonal partition is obtained from the profile of the matrix. An iterative strategy is then used to further refine the partitioning by allowing nodes to be transferred between neighboring partitions. Experiments are performed on matrices arising from real-world applications to show the feasibility and usefulness of this approach.

  20. 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...

  1. Knowledge base rule partitioning design for CLIPS

    NASA Technical Reports Server (NTRS)

    Mainardi, Joseph D.; Szatkowski, G. P.

    1990-01-01

    This describes a knowledge base (KB) partitioning approach to solve the problem of real-time performance using the CLIPS AI shell when containing large numbers of rules and facts. This work is funded under the joint USAF/NASA Advanced Launch System (ALS) Program as applied research in expert systems to perform vehicle checkout for real-time controller and diagnostic monitoring tasks. The Expert System advanced development project (ADP-2302) main objective is to provide robust systems responding to new data frames of 0.1 to 1.0 second intervals. The intelligent system control must be performed within the specified real-time window, in order to meet the demands of the given application. Partitioning the KB reduces the complexity of the inferencing Rete net at any given time. This reduced complexity improves performance but without undo impacts during load and unload cycles. The second objective is to produce highly reliable intelligent systems. This requires simple and automated approaches to the KB verification & validation task. Partitioning the KB reduces rule interaction complexity overall. Reduced interaction simplifies the V&V testing necessary by focusing attention only on individual areas of interest. Many systems require a robustness that involves a large number of rules, most of which are mutually exclusive under different phases or conditions. The ideal solution is to control the knowledge base by loading rules that directly apply for that condition, while stripping out all rules and facts that are not used during that cycle. The practical approach is to cluster rules and facts into associated 'blocks'. A simple approach has been designed to control the addition and deletion of 'blocks' of rules and facts, while allowing real-time operations to run freely. Timing tests for real-time performance for specific machines under R/T operating systems have not been completed but are planned as part of the analysis process to validate the design.

  2. 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.

  3. 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.

  4. 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.

  5. Entanglement concentration of three-partite states

    SciTech Connect

    Groisman, Berry; Linden, Noah; Popescu, Sandu

    2005-12-15

    We investigate the concentration of multiparty entanglement by focusing on a simple family of three-partite pure states, superpositions of Greenberger-Horne-Zeilinger states and singlets. Despite the simplicity of the states, we show that they cannot be reversibly concentrated by the standard entanglement concentration procedure, to which they seem ideally suited. Our results cast doubt on the idea that for each N there might be a finite set of N-party states into which any pure state can be reversibly transformed. We further relate our results to the concept of locking of entanglement of formation.

  6. 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.

  7. Evaporative partitioning in a unified land model

    NASA Astrophysics Data System (ADS)

    Livneh, B.; Lettenmaier, D. P.; Restrepo, P. J.

    2009-12-01

    Accurate partitioning of precipitation into evapotranspiration and runoff, and more generally estimation of the surface water balance, is crucial both for hydrologic forecasting and numerical weather and climate prediction. One important aspect of this issue is the partitioning of evapotranspiration into soil evaporation, canopy evaporation, and plant transpiration, which in turn has implications for other terms in the surface water balance. In the first part of the study, we tested several well known land surface models in multi-year simulations over the continental U.S. Among the models, which included the Variable Infiltration Capacity (VIC) model, the Community Land Model (CLM), the Noah Land Surface Model (Noah LSM), and the NASA Catchment model, there were substantial variations in the partitioning. These results motivated a more detailed evaluation, using data for two catchments that were a part of the second phase of the Distributed Model Intercomparison Project (DMIP-2), the East Fork Carson River Basin and the Illinois River Basin. In this portion of the study, we evaluated a unified land model (ULM) which is a merger of the NWS Sacramento Soil Moisture Accounting model (SAC-SMA), which is used operationally for flood and seasonal streamflow prediction, and the Noah LSM, which is the land scheme used in NOAA’s suite of weather and climate prediction models. Our overall objective is to leverage the operational strengths of each model, specifically to improve streamflow prediction and soil moisture states within the Noah LSM framework, and to add a vegetation component to the SAC-SMA model. Partitioning of evapotranspiration into its three components is a key part of the ULM performance, and controls our ability to use calibrated SAC-SMA parameters within the ULM framework. In our evaluations at the DMIP-2 sites, we examined sensitivities of soil moisture and evaporative components in ULM to changes in vegetation cover, root zone depth, canopy

  8. 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.

  9. 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.

  10. 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.

  11. Thermochromic Solids

    NASA Astrophysics Data System (ADS)

    Hughes, Jeffrey G.

    1998-01-01

    Thermochromism is the reversible change of color of a solid when it is heated or cooled. Previous reported examples of thermochromic solids involve color changes due to changes of stereochemistry. Salts of mercuric iodide, M2HgI4 [M=Cu(I), Ag(I)] are easily prepared and exhibit sharp, reversible thermochromic transitions at moderately low temperatures. The Ag(I) solid changes color from yellow to orange at 50 °C and the Cu(I) solid at 67 °C. The color changes are due to subtle changes in crystal structure. Signs can be prepared for lecture demonstrations using pieces of filter paper saturated in the solids

  12. 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. PMID:27182055

  13. Modular properties of full 5D SYM partition function

    NASA Astrophysics Data System (ADS)

    Qiu, Jian; Tizzano, Luigi; Winding, Jacob; Zabzine, Maxim

    2016-03-01

    We study properties of the full partition function for the U(1) 5D N = {2}^{ast } gauge theory with adjoint hypermultiplet of mass M . This theory is ultimately related to abelian 6D (2,0) theory. We construct the full non-perturbative partition function on toric Sasaki-Einstein manifolds by gluing flat copies of the Nekrasov partition function and we express the full partition function in terms of the generalized double elliptic gamma function G 2 C associated with a certain moment map cone C. The answer exhibits a curious SL(4 , ℤ) modular property. Finally, we propose a set of rules to construct the partition function that resembles the calculation of 5d supersymmetric partition function with the insert ion of defects of various co-dimensions.

  14. A Robustness Testing Campaign for IMA-SP Partitioning Kernels

    NASA Astrophysics Data System (ADS)

    Grixti, Stephen; Lopez Trecastro, Jorge; Sammut, Nicholas; Zammit-Mangion, David

    2015-09-01

    With time and space partitioned architectures becoming increasingly appealing to the European space sector, the dependability of partitioning kernel technology is a key factor to its applicability in European Space Agency projects. This paper explores the potential of the data type fault model, which injects faults through the Application Program Interface, in partitioning kernel robustness testing. This fault injection methodology has been tailored to investigate its relevance in uncovering vulnerabilities within partitioning kernels and potentially contributing towards fault removal campaigns within this domain. This is demonstrated through a robustness testing case study of the XtratuM partitioning kernel for SPARC LEON3 processors. The robustness campaign exposed a number of vulnerabilities in XtratuM, exhibiting the potential benefits of using such a methodology for the robustness assessment of partitioning kernels.

  15. 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.

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

    DOEpatents

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

    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.

  17. 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

  18. TAP - Tools for Adaptive Partitioning v. 0.99 Beta

    Energy Science and Technology Software Center (ESTSC)

    2008-11-19

    TAP is a set of tools which are essential for conducting research on adaptive partitioners. The basic premise is that a single partitioner may not be a good choice for adaptive mesh simulations; rather one must match a partitioner (obtained from a partitioning package like Zoltan, ParMetis etc) with the mesh being partitioned. TAP provides the tools that can judge the suitability of a partitioning algorithm to a given mesh.

  19. 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…

  20. Strainrange partitioning: A total strain range version

    NASA Technical Reports Server (NTRS)

    Halford, G. R.; Saltsman, J. F.

    1983-01-01

    Procedures are presented for expressing the Strainrange Partitioning (SRP) method for creep fatigue life prediction in terms of total strain range. Inelastic and elastic strain-range - life relations are summed to give total strain-range - life relations. The life components due to inelastic strains are dealt with using conventional SRP procedures while the life components due to elastic strains are expressed as families of time-dependent terms for each type of SRP cycle. Cyclic constitutive material behavior plays an important role in establishing the elastic strain-range - life relations as well as the partitioning of the inelastic strains. To apply the approach, however, it is not necessary to have to determine the magnitude of the inelastic strain range. The total strain SRP approach is evaluated and verified using two nickel base superalloys, AF2-1DA and Rene 95. Excellent agreement is demonstrated between observed and predicted cyclic lifetimes with 70 to 80 percent of the predicted lives falling within factors of two of the observed lives. The total strain-range SRP approach should be of considerable practical value to designers who are faced with creep-fatigue problems for which the inelastic strains cannot be calculated with sufficient accuracy to make reliable life predictions by the conventional inelastic strain range SRP approach.

  1. Gait Partitioning Methods: A Systematic Review.

    PubMed

    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

  2. Inversion of hematocrit partition at microfluidic bifurcations.

    PubMed

    Shen, Zaiyi; Coupier, Gwennou; Kaoui, Badr; Polack, Benoît; Harting, Jens; Misbah, Chaouqi; Podgorski, Thomas

    2016-05-01

    Partitioning of red blood cells (RBCs) at the level of bifurcations in the microcirculatory system affects many physiological functions yet it remains poorly understood. We address this problem by using T-shaped microfluidic bifurcations as a model. Our computer simulations and in vitro experiments reveal that the hematocrit (ϕ0) partition depends strongly on RBC deformability, as long as ϕ0<20% (within the normal range in microcirculation), and can even lead to complete deprivation of RBCs in a child branch. Furthermore, we discover a deviation from the Zweifach-Fung effect which states that the child branch with lower flow rate recruits less RBCs than the higher flow rate child branch. At small enough ϕ0, we get the inverse scenario, and the hematocrit in the lower flow rate child branch is even higher than in the parent vessel. We explain this result by an intricate up-stream RBC organization and we highlight the extreme dependence of RBC transport on geometrical and cell mechanical properties. These parameters can lead to unexpected behaviors with consequences on the microcirculatory function and oxygen delivery in healthy and pathological conditions. PMID:26744089

  3. 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.

  4. Approximate algorithms for partitioning and assignment problems

    NASA Technical Reports Server (NTRS)

    Iqbal, M. A.

    1986-01-01

    The problem of optimally assigning the modules of a parallel/pipelined program over the processors of a multiple computer system under certain restrictions on the interconnection structure of the program as well as the multiple computer system was considered. For a variety of such programs it is possible to find linear time if a partition of the program exists in which the load on any processor is within a certain bound. This method, when combined with a binary search over a finite range, provides an approximate solution to the partitioning problem. The specific problems considered were: a chain structured parallel program over a chain-like computer system, multiple chain-like programs over a host-satellite system, and a tree structured parallel program over a host-satellite system. For a problem with m modules and n processors, the complexity of the algorithm is no worse than O(mnlog(W sub T/epsilon)), where W sub T is the cost of assigning all modules to one processor and epsilon the desired accuracy.

  5. Unsupervised image categorization by hypergraph partition.

    PubMed

    Huang, Yuchi; Liu, Qingshan; Lv, Fengjun; Gong, Yihong; Metaxas, Dimitris N

    2011-06-01

    We present a framework for unsupervised image categorization in which images containing specific objects are taken as vertices in a hypergraph and the task of image clustering is formulated as the problem of hypergraph partition. First, a novel method is proposed to select the region of interest (ROI) of each image, and then hyperedges are constructed based on shape and appearance features extracted from the ROIs. Each vertex (image) and its k-nearest neighbors (based on shape or appearance descriptors) form two kinds of hyperedges. The weight of a hyperedge is computed as the sum of the pairwise affinities within the hyperedge. Through all of the hyperedges, not only the local grouping relationships among the images are described, but also the merits of the shape and appearance characteristics are integrated together to enhance the clustering performance. Finally, a generalized spectral clustering technique is used to solve the hypergraph partition problem. We compare the proposed method to several methods and its effectiveness is demonstrated by extensive experiments on three image databases. PMID:21282850

  6. 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.

  7. Partitioning of on-demand electron pairs

    NASA Astrophysics Data System (ADS)

    Ubbelohde, Niels; Hohls, Frank; Kashcheyevs, Vyacheslavs; Wagner, Timo; Fricke, Lukas; Kästner, Bernd; Pierz, Klaus; Schumacher, Hans W.; Haug, Rolf J.

    2015-01-01

    The on-demand generation and separation of entangled photon pairs are key components of quantum information processing in quantum optics. In an electronic analogue, the decomposition of electron pairs represents an essential building block for using the quantum state of ballistic electrons in electron quantum optics. The scattering of electrons has been used to probe the particle statistics of stochastic sources in Hanbury Brown and Twiss experiments and the recent advent of on-demand sources further offers the possibility to achieve indistinguishability between multiple sources in Hong-Ou-Mandel experiments. Cooper pairs impinging stochastically at a mesoscopic beamsplitter have been successfully partitioned, as verified by measuring the coincidence of arrival. Here, we demonstrate the splitting of electron pairs generated on demand. Coincidence correlation measurements allow the reconstruction of the full counting statistics, revealing regimes of statistically independent, distinguishable or correlated partitioning, and have been envisioned as a source of information on the quantum state of the electron pair. The high pair-splitting fidelity opens a path to future on-demand generation of spin-entangled electron pairs from a suitably prepared two-electron quantum-dot ground state.

  8. Determining Peptide Partitioning Properties via Computer Simulation

    PubMed Central

    Ulmschneider, Jakob P.; Ulmschneider, Martin B.

    2010-01-01

    The transfer of polypeptide segments into lipid bilayers to form transmembrane helices represents the crucial first step in cellular membrane protein folding and assembly. This process is driven by complex and poorly understood atomic interactions of peptides with the lipid bilayer environment. The lack of suitable experimental techniques that can resolve these processes both at atomic resolution and nanosecond timescales has spurred the development of computational techniques. In this review, we summarize the significant progress achieved in the last few years in elucidating the partitioning of peptides into lipid bilayer membranes using atomic detail molecular dynamics simulations. Indeed, partitioning simulations can now provide a wealth of structural and dynamic information. Furthermore, we show that peptide-induced bilayer distortions, insertion pathways, transfer free energies, and kinetic insertion barriers are now accurate enough to complement experiments. Further advances in simulation methods and force field parameter accuracy promise to turn molecular dynamics simulations into a powerful tool for investigating a wide range of membrane active peptide phenomena. PMID:21107546

  9. 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

  10. Life prediction modeling based on strainrange partitioning

    NASA Technical Reports Server (NTRS)

    Halford, Gary R.

    1988-01-01

    Strainrange partitioning (SRP) is an integrated low-cycle-fatigue life predicting system. It was created specifically for calculating cyclic crack initiation life under severe high-temperature fatigue conditions. The key feature of the SRP system is its recognition of the interacting mechanisms of cyclic inelastic deformation that govern cyclic life at high temperatures. The SRP system bridges the gap between the mechanistic level of understanding that breeds new and better materials and the phenomenological level wherein workable engineering life prediction methods are in great demand. The system was recently expanded to address engineering fatigue problems in the low-strain, long-life, nominally elastic regime. This breakthrough, along with other advances in material behavior and testing technology, has permitted the system to also encompass low-strain thermomechanical loading conditions. Other important refinements of the originally proposed method include procedures for dealing with life-reducing effects of multiaxial loading, ratcheting, mean stresses, nonrepetitive (cumulative loading) loading, and environmental and long-time exposure. Procedure were also developed for partitioning creep and plastic strain and for estimating strainrange versus life relations from tensile and creep rupture properties. Each of the important engineering features of the SRP system are discussed and examples shown of how they help toward predicting high-temperature fatigue life under practical, although complex, loading conditions.

  11. 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.

  12. Diffusive isothermal partitioning in a layered medium with geologic applications

    NASA Technical Reports Server (NTRS)

    Hopper, R. W.; Uhlmann, D. R.

    1976-01-01

    The diffusive isothermal partitioning of solute in a layered two-phase material has been analyzed to help elucidate the phenomenon of solute partitioning in multiphase lunar and terrestrial materials and to estimate the cooling history of samples. After reviewing the physical chemistry of partitioning and the case of an infinite one-dimensional diffusion couple, we solve in analytic form the case of a finite one-dimensional couple. The solution can be used to estimate cooling histories or to interpret laboratory experiments on partitioning. A sample calculation is included.

  13. A Framework for Parallel Nonlinear Optimization by Partitioning Localized Constraints

    SciTech Connect

    Xu, You; Chen, Yixin

    2008-06-28

    We present a novel parallel framework for solving large-scale continuous nonlinear optimization problems based on constraint partitioning. The framework distributes constraints and variables to parallel processors and uses an existing solver to handle the partitioned subproblems. In contrast to most previous decomposition methods that require either separability or convexity of constraints, our approach is based on a new constraint partitioning theory and can handle nonconvex problems with inseparable global constraints. We also propose a hypergraph partitioning method to recognize the problem structure. Experimental results show that the proposed parallel algorithm can efficiently solve some difficult test cases.

  14. Molecular partitioning based on the kinetic energy density

    NASA Astrophysics Data System (ADS)

    Noorizadeh, Siamak

    2016-05-01

    Molecular partitioning based on the kinetic energy density is performed to a number of chemical species, which show non-nuclear attractors (NNA) in their gradient maps of the electron density. It is found that NNAs are removed using this molecular partitioning and although the virial theorem is not valid for all of the basins obtained in the being used AIM, all of the atoms obtained using the new approach obey this theorem. A comparison is also made between some atomic topological parameters which are obtained from the new partitioning approach and those calculated based on the electron density partitioning.

  15. 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. PMID:26810802

  16. 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

  17. EVALUATION OF REVERSE PHASE LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY FOR ESTIMATION OF N-OCTANOL/WATER PARTITION COEFFICIENTS FOR ORGANIC CHEMICALS

    EPA Science Inventory

    A reverse-phase high pressure liquid chromatography/mass spectrometry (HPLC/MS) method was developed for estimating n-octanol/water partition coefficients (K sub ow) of anthropogenic molecules in complex chemical mixtures (e.g., complex effluents and solid waste leachates). The a...

  18. 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

  19. Structural Determinants of Drug Partitioning in n-Hexadecane/Water System

    PubMed Central

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

    2013-01-01

    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 transport and partitioning. Solvation in strata of the phospholipid bilayer is an important drug characteristics 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 by

  20. 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...

  1. Rosuvastatin Liver Partitioning in Cynomolgus Monkeys: Measurement In Vivo and Prediction Using In Vitro Monkey Hepatocyte Uptake.

    PubMed

    Morse, Bridget L; Cai, Hong; MacGuire, Jamus G; Fox, Maxine; Zhang, Lisa; Zhang, Yueping; Gu, Xiaomei; Shen, Hong; Dierks, Elizabeth A; Su, Hong; Luk, Chiuwa E; Marathe, Punit; Shu, Yue-Zhong; Humphreys, W Griffith; Lai, Yurong

    2015-11-01

    Unbound plasma concentrations may not reflect those in target tissues, and there is a need for methods to predict tissue partitioning. Here, we investigate the unbound liver partitioning (Kpu,u) of rosuvastatin, a substrate of hepatic organic anion transporting peptides, in cynomolgus monkeys and compare it with that determined using hepatocytes in vitro. Rosuvastatin (3 mg/kg) was administered orally to monkeys and plasma and liver (by ultrasound-guided biopsy) collected over time. Uptake into monkey hepatocytes was evaluated up to steady state. Binding in monkey plasma, liver, and hepatocytes was determined using equilibrium dialysis. Mean in vivo Kpu,u was 118 after correcting total liver partitioning by plasma and liver binding. In vitro uptake data were analyzed by compartmental modeling to determine active uptake clearance, passive diffusion, the intracellular unbound fraction, and Kpu,u. In vitro Kpu,u underpredicted that in vivo, resulting in the need for an empirical in vitro to in vivo scaling factor of 10. Adjusting model parameters using hypothetical scaling factors for transporter expression and surface area or assuming no effect of protein binding on active transport increased partitioning values by 1.1-, 6-, and 9-fold, respectively. In conclusion, in vivo rosuvastatin unbound liver partitioning in monkeys was underpredicted using hepatocytes in vitro. Modeling approaches that allow integrating corrections from passive diffusion or protein binding on active uptake could improve the estimation of in vivo intracellular partitioning of this organic anion transporting peptide substrate. A similar assessment of other active hepatic transport mechanisms could confirm and determine the extent to which limited accumulation in isolated hepatocytes needs to be considered in drug development. PMID:26341276

  2. Sludge accumulation pattern inside oxidation ditch case study.

    PubMed

    Fouad, Moharram; El-Morsy, Ahmed

    2014-01-01

    The sludge accumulation pattern of an oxidation ditch (OD) plant treating municipal wastewater was observed under dry and wet weather conditions, during 3 years of operation. The accumulation patterns along the ditches and their rates were revealed. In addition, the composition of the accumulation was investigated. Finally, the ratio of sand and volatile particles, mixed liquor suspended solids (MLSS), and mixed liquor volatile suspended solids, as well as the removal efficiency were also observed against the accumulated sludge. Further, a laboratory-scale channel was used to investigate the settleability of grit after mixing with variable values of MLSS. The observed results indicated that the economical design and operation of ODs using a velocity value between 0.3-0.35 m/s is not recommended, to avoid the settling of all solids. High values of MLSS and sludge age need high horizontal velocity (more than 0.35 m/s) and more power to avoid settling problems and system failure. The influence of flow velocity on the sludge settleability was studied, enabling better planning of future ditch design and operation. PMID:24960009

  3. Imperfect asymmetry: The mechanism governing asymmetric partitioning of damaged cellular components during mitosis

    PubMed Central

    Pattabiraman, Sundararaghavan; Kaganovich, Daniel

    2014-01-01

    Aging is universally associated with organism-wide dysfunction and a decline in cellular fitness. From early development onwards, the efficiency of self-repair, energy production, and homeostasis all decrease. Due to the multiplicity of systems that undergo agingrelated decline, the mechanistic basis of organismal aging has been difficult to pinpoint. At the cellular level, however, recent work has provided important insight. Cellular aging is associated with the accumulation of several types of damage, in particular damage to the proteome and organelles. Groundbreaking studies have shown that replicative aging is the result of a rejuvenation mechanism that prevents the inheritance of damaged components during division, thereby confining the effects of aging to specific cells, while removing damage from others. Asymmetric inheritance of misfolded and aggregated proteins, as well as reduced mitochondria, has been shown in yeast. Until recently, however, it was not clear whether a similar mechanism operates in mammalian cells, which were thought to mostly divide symmetrically. Our group has recently shown that vimentin establishes mitotic polarity in immortalized mammalian cells, and mediates asymmetric partitioning of multiple factors through direct interaction. These findings prompt a provocative hypothesis: that intermediate filaments serve as asymmetric partitioning modules or “sponges” that, when expressed prior to mitosis, can “clean” emerging cells of the damage they have accumulated. PMID:25941938

  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. 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...

  6. 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.

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

    DOE PAGESBeta

    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

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

    PubMed

    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

  9. 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

  10. F-Cl-OH partitioning between biotite and apatite

    NASA Astrophysics Data System (ADS)

    Zhu, Chen; Sverjensky, Dimitri A.

    1992-09-01

    An assessment of F-C1-OH partitioning between natural apatite and biotite in a variety of rocks was used to evaluate reciprocal (Mg, Fe 2+, Al VI) (F, Cl, OH) mixing properties for biotite according to the reciprocal salt solution model of WOOD and NICHOLLS (1978). Ideal mixing of F-C1-OH and Fe-Mg-Al VI in the hydroxyl and octahedral sites is assumed for biotites with dilute Cl concentrations. The reciprocal interaction parameters, in terms of Gibbs free energies, for the reactions KMg3[ AlSi3O10]( OH) 2 + KFe3[ AlSi3O10]( F) 2 = KMg3[ AlSi3O10]( F) 2 + KFe3[ AlSi3O10]( OH) 2 Phl Fann Fphl Ann and KMg3[ AlSi3O10]( Cl) 2 + KFe3[ AlSi3O10]( OH) 2 = KMg3[ AlSi3O10]( OH) 2 + KFe3[ AlSi3O10] ( Cl) 2 Clphl Ann Phl Clann are about -10 kcal/mol and -4.5 kcal/mol, respectively. These mixing properties are consistent with standard state thermodynamic properties for F and Cl endmember phases from ZHU and SVERJENSKY (1991). The approach of studying F-C1-OH partitioning between biotite and apatite permits distinguishing the reciprocal effects from the effects of temperature, pressure, and fluid composition. The resultant mixing properties are consistent with observations both in hydrothermal experiments and in natural mineral assemblages. The mixing properties presented in this study enable us now to predict F and Cl concentrations of hydrothermal fluids from the measured F and Cl concentrations in biotite with variable Fe-Mg-Al VI proportions. A case study of the Santa Rita porphyry copper deposits, New Mexico, shows that hydrothermal fluids responsible for the phyllic alteration had a salinity about 3 molal Cl -, in agreement with fluid inclusion studies. Our internally consistent standard thermodynamic properties and solid solution models also lead to recalibration of the apatite-biotite geothermometer. The revised geothermometer predicts temperatures that agree with those estimated from other independent geothermometers. The large reciprocal effects in biotite also point

  11. 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

  12. 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

  13. Interspecific resource partitioning in sympatric ursids.

    PubMed

    Belant, Jerrold L; Kielland, Knut; Follmann, Erich H; Adams, Layne G

    2006-12-01

    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 south-central 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

  14. Traceds: An Experimental Trace Element Partitioning Database

    NASA Astrophysics Data System (ADS)

    Nielsen, R. L.; Ghiorso, M. S.

    2014-12-01

    The goal of this project, which is part of the EARTHCHEM initiative, is to compile the existing experimental trace element partitioning data, and to develop a transparent, accessible resource for the community. The primary goal of experimental trace element partitioning studies is to create a database that can be used to develop models of how trace elements behave in natural geochemical systems. The range of approaches as to how this is accomplished and how the data are reported differs dramatically from one system to another and one investigator to another. This provides serious challenges to the creation of a coherent database - and suggests the need for a standard format for data presentation and reporting. The driving force for this compilation is to provide community access to the complete database for trace element experiments. Our new effort includes all the published analytical results from experimental determinations. In compiling the data, we have set a minimum standard for the data to be included. The threshold criteria include: Experimental conditions (temperature, pressure, device, container, time, etc.) Major element composition of the phases Trace element analyses of the phases Data sources that did not report these minimum components were not included. The rationale for not including such data is that the degree of equilibration is unknown, and more important, no rigorous approach to modeling the behavior of trace elements is possible without a knowledge of the actual concentrations or the temperature and pressure of formation. The data are stored using a schema derived from that of the Library of Experimental Phase Relations (LEPR), modified to account for additional metadata, and restructured to permit multiple analytical entries for various element/technique/standard combinations. Our ultimate goal is to produce a database together with a flexible user interface that will be useful for experimentalists to set up their work and to build

  15. 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.

  16. Three-phase partitioning of hydrolyzed levan.

    PubMed

    Coimbra, Cynthia Gisele de Oliveira; Lopes, Carlos Edison; Calazans, Glícia Maria Torres

    2010-06-01

    During the fructose and polymerization to synthesize levan, smaller fructooligosaccharide (FOS) molecules are produced. FOS can also be obtained by levan hydrolysis. Three-phase partitioning (TPP) is a separation technique that has been used for polysaccharide precipitation and gathers t-butanol and ammonium sulphate to exclude the polymer from the aqueous solution. In this work TPP was tested to separate levan and FOS from aqueous solution. The FOS used was obtained from Zymomonas mobilis levan acid hydrolysis and fractionation with ethanol. The yield of low TPP fractions was higher than those obtained from the native levan. The F-90 exhibited a higher yield than other fractions. However, when applying the TPP technique to lightest fraction not precipitated by ethanol at 90% (F>90), the intermediate phase was not possible to be visualize. These results have potential application because they show that by using the levan TPP separation it is possible to separate low-molecular weight sugar. PMID:20163956

  17. Hypergraph Partitioning for Automatic Memory Hierarchy Management

    SciTech Connect

    Krishnamoorthy, Sriram; Catalyurek, Umit; Nieplocha, Jarek; Rountev, Atanas; Sadayappan, Ponnuswamy

    2007-11-15

    The paper presents present a mechanism for automatic management of the memory hierarchy, including secondary storage, in the context of a global address space parallel programming framework. The programmer specifies the parallelism and locality in the computation. The scheduling of the computation into stages, together with the movement of the associated data between secondary storage and global memory, and between global memory and local memory, is automatically managed by the framework. A novel formulation of hypergraph partitioning is used to model the optimization problem of minimizing disk I/O by improving locality of access. Experimental evaluation of the proposed approach using a sub-computation from the quantum chemistry domain shows a reduction in the disk I/O cost by upto a factor of 11, and a reduction in turnaround time by upto 97%, as compared to alternatives used in state-of-the-art quantum chemistry codes.

  18. Exometabolite niche partitioning among sympatric soil bacteria

    DOE PAGESBeta

    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; et al

    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

  19. Multicore Software Architectures on Virtualized Partitioned Systems

    NASA Astrophysics Data System (ADS)

    Carrascosa, E.; Masmano, M.; Balbastre, P.; Crespo, A.; Galizzi, J.

    2014-08-01

    Embedded system design is evolving in terms of complexity towards the use of multiprocessor architectures, increasing performance and reducing costs while presenting a low impact on critical design aspects. However, the use of multi-core technologies entails an increment in the level of indeterminism that is not acceptable for safety critical applications where predictability is crucial. This paper focuses on analysing the factors related to indeterminism on multicore systems and the methods to attenuate their impact, providing a series of guidelines aimed to obtain on-board software qualification. Time and space partitioning (TSP) is presented as a suitable mean to handle indeterminism, while XtratuM, an open source TSP hyper-visor designed to comply with safety critical real-time requirements, has been selected to adopt a practical approach to the subject.

  20. Energy Partition and Variability of Earthquakes

    NASA Astrophysics Data System (ADS)

    Kanamori, H.

    2003-12-01

    During an earthquake the potential energy (strain energy + gravitational energy + rotational energy) is released, and the released potential energy (Δ W) is partitioned into radiated energy (ER), fracture energy (EG), and thermal energy (E H). How Δ W is partitioned into these energies controls the behavior of an earthquake. The merit of the slip-weakening concept is that only ER and EG control the dynamics, and EH can be treated separately to discuss the thermal characteristics of an earthquake. In general, if EG/E_R is small, the event is ``brittle", if EG /ER is large, the event is ``quasi static" or, in more common terms, ``slow earthquakes" or ``creep". If EH is very large, the event may well be called a thermal runaway rather than an earthquake. The difference in energy partition has important implications for the rupture initiation, evolution and excitation of long-period ground motions from very large earthquakes. We review the current state of knowledge on this problem in light of seismological observations and the basic physics of fracture. With seismological methods, we can measure only ER and the lower-bound of Δ W, Δ W0, and estimation of other energies involves many assumptions. ER: Although ER can be directly measured from the radiated waves, its determination is difficult because a large fraction of energy radiated at the source is attenuated during propagation. With the commonly used teleseismic and regional methods, only for events with MW>7 and MW>4, respectively, we can directly measure more than 10% of the total radiated energy. The rest must be estimated after correction for attenuation. Thus, large uncertainties are involved, especially for small earthquakes. Δ W0: To estimate Δ W0, estimation of the source dimension is required. Again, only for large earthquakes, the source dimension can be estimated reliably. With the source dimension, the static stress drop, Δ σ S, and Δ W0, can be estimated. EG: Seismologically, EG is the energy

  1. 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

  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. 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.

  4. 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.

  5. 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

  6. Exometabolite niche partitioning among sympatric soil bacteria.

    PubMed

    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

  7. 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

  8. Temperature and pressure dependence of Ni partitioning between olivine and high-MgO silicate melts

    NASA Astrophysics Data System (ADS)

    Matzen, A. K.; Baker, M. B.; Beckett, J.; Stolper, E. M.

    2010-12-01

    composition. Using our model in conjunction with predictions of partial melting (BATCH [5]), we predict that when a deep partial melt of depleted mantle [6] (8% melt from 3.6 GPa) is brought to low P (0.1 GPa) and allowed to crystallize, the low P olivines will have significantly higher NiO contents (~0.44 wt %) than those in the mantle source (0.33 wt %), reflecting the decrease in the partition coefficient from the mantle source to the near-surface crystallization conditions . Estimates of solid and liquid component partial molar volumes suggests that P has only a small effect on the Ni-Mg exchange and thus that T and liquid composition are the most important variables over the P-T range spanned by this calculation. The effect of temperature on Ni partitioning can account for olivine phenocrysts with higher NiO contents than those in normal mantle peridotites, and thus may contribute to the high-NiO contents of many olivine phenocrysts from Hawaii [2].
    [1] Putirka (2005) G3, 6. [2] Sobolev et al. (2005) Nature 434, 590-597. [3] Hart & Davis (1978) EPSL 40, 203-219. [4] Li & Ripley (2010) Chem Geo 275, 129-138. [5] Longhi (2002) G3, 3. [6] Workman & Hart (2005) ESPL 231, 53-72.

  9. 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. PMID:27136717

  10. Comparison of nonplanar and coplanar PCB congener partitioning in seawater and bioaccumulation in blue mussels (Mytilus edulis)

    SciTech Connect

    Bergen, B.J.; Nelson, W.G.; Pruell, R.J.

    1996-09-01

    The partitioning of 18 nonplanar and three coplanar polychlorinated biphenyl (PCB) congeners was quantified in New Bedford Harbor, Massachusetts. Concurrently, bioaccumulation of these congeners was measured in blue mussels deployed for 7 and 28 d in New Bedford Harbor, and bioconcentration factors (BCFs) were calculated for each congener. The PCB concentrations measured in the dissolved and particulate fractions of seawater samples were used to calculate partition coefficients (K{sub p}) for each congener. These values were correlated with reported octanol/water partition coefficients (K{sub ow}). No significant differences (p > 0.05) were observed in the relationships between K{sub p} and K{sub ow} for the coplanar congeners relative to the nonplanar congeners. Coplanar congeners reached steady state faster than the nonplanar congeners; however, after 28 d a similar relationship was observed between BCF and K{sub ow} in coplanar and nonplanar congeners. These data indicate that coplanar PCBs partition in seawater and accumulate in mussels similarly to nonplanar PCBs with the same number of chlorines.

  11. 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..

  12. The Emergence of DP in the Partitive Structure

    ERIC Educational Resources Information Center

    Stickney, Helen

    2009-01-01

    This dissertation is a first look at English-speaking children's acquisition of the syntax of the partitive. It presents four experiments that contrast three types of structures and examines how they interact with adjectival modification: the partitive, the pseudopartitive and complex nouns with prepositional adjuncts. The experimentation…

  13. High-temperature asymptotics of supersymmetric partition functions

    NASA Astrophysics Data System (ADS)

    Ardehali, Arash Arabi

    2016-07-01

    We study the supersymmetric partition function of 4d supersymmetric gauge theories with a U(1) R-symmetry on Euclidean S 3 × S β 1 , with S 3 the unit-radius squashed three-sphere, and β the circumference of the circle. For superconformal theories, this partition function coincides (up to a Casimir energy factor) with the 4d superconformal index.

  14. Knowledge Partitioning in Categorization: Constraints on Exemplar Models

    ERIC Educational Resources Information Center

    Yang, Lee-Xieng; Lewandowsky, Stephan

    2004-01-01

    The authors present 2 experiments that establish the presence of knowledge partitioning in perceptual categorization. Many participants learned to rely on a context cue, which did not predict category membership but identified partial boundaries, to gate independent partial categorization strategies. When participants partitioned their knowledge,…

  15. 47 CFR 101.1111 - Partitioning and disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 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...

  16. 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...

  17. 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 disaggregation. 27.15 Section 27.15 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Applications and Licenses § 27.15 Geographic partitioning and spectrum disaggregation....

  18. 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.

  19. 47 CFR 101.1415 - Partitioning and disaggregation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Partitioning and disaggregation. 101.1415 Section 101.1415 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Multichannel Video Distribution and Data Service Rules for the 12.2-12.7 GHz Band § 101.1415 Partitioning...

  20. 47 CFR 101.1415 - 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. 101.1415 Section 101.1415 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Multichannel Video Distribution and Data Service Rules for the 12.2-12.7 GHz Band § 101.1415 Partitioning...

  1. 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 ...

  2. 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...

  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, 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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....

  16. 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...

  17. 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...

  18. 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...

  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 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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....

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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.

  12. Evidence accumulation for spatial reasoning

    NASA Technical Reports Server (NTRS)

    Matsuyama, T.; Hwang, V. S. S.; Davis, L. S.

    1984-01-01

    The evidence accumulation proces of an image understanding system is described enabling the system to perform top-down(goal-oriented) picture processing as well as bottom-up verification of consistent spatial relations among objects.

  13. Recursive partitioning for heterogeneous causal effects.

    PubMed

    Athey, Susan; Imbens, Guido

    2016-07-01

    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

  14. Nonsense codons trigger an RNA partitioning shift.

    PubMed

    Bhalla, Angela D; Gudikote, Jayanthi P; Wang, Jun; Chan, Wai-Kin; Chang, Yao-Fu; Olivas, O Renee; Wilkinson, Miles F

    2009-02-13

    T-cell receptor-beta (TCRbeta) genes naturally acquire premature termination codons (PTCs) as a result of programmed gene rearrangements. PTC-bearing TCRbeta transcripts are dramatically down-regulated to protect T-cells from the deleterious effects of the truncated proteins that would otherwise be produced. Here we provide evidence that two responses collaborate to elicit this dramatic down-regulation. One is rapid mRNA decay triggered by the nonsense-mediated decay (NMD) RNA surveillance pathway. We demonstrate that this occurs in highly purified nuclei lacking detectable levels of three different cytoplasmic markers, but containing an outer nuclear membrane marker, suggesting that decay occurs either in the nucleoplasm or at the outer nuclear membrane. The second response is a dramatic partitioning shift in the nuclear fraction-to-cytoplasmic fraction mRNA ratio that results in few TCRbeta transcripts escaping to the cytoplasmic fraction of cells. Analysis of TCRbeta mRNA kinetics after either transcriptional repression or induction suggested that this nonsense codon-induced partitioning shift (NIPS) response is not the result of cytoplasmic NMD but instead reflects retention of PTC(+) TCRbeta mRNA in the nuclear fraction of cells. We identified TCRbeta sequences crucial for NIPS but found that NIPS is not exclusively a property of TCRbeta transcripts, and we identified non-TCRbeta sequences that elicit NIPS. RNA interference experiments indicated that NIPS depends on the NMD factors UPF1 and eIF4AIII but not the NMD factor UPF3B. We propose that NIPS collaborates with NMD to retain and degrade a subset of PTC(+) transcripts at the outer nuclear membrane and/or within the nucleoplasm. PMID:19091751

  15. 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

  16. The partition of regional sea level variability

    NASA Astrophysics Data System (ADS)

    Forget, Gaël; Ponte, Rui M.

    2015-09-01

    The existing altimetric record offers an unprecedented view of sea level (ζ) variability on a global scale for more than 2 decades. Optimal inference from the data involves appropriate partition of signal and noise, in terms of relevant scales, physical processes and forcing mechanisms. Such partition is achieved here through fitting a general circulation model to altimeter and other datasets to produce a "best" estimate of ζ variability directly forced by the atmosphere-the signal of primary interest here. In this context noise comes primarily from instrument errors and meso-scale eddies, as expected, but spatial smoothing effectively reduces this noise. A separate constraint is thus formulated to measure the fit to monthly, large-scale altimetric variability that unlike the daily, pointwise constraint shows a high signal-to-noise ratio. The estimate is explored to gain insight into dynamics, forcing, and other factors controlling ζ variability. Contributions from thermo-steric, halo-steric and bottom pressure terms are all important depending on region, but slopes of steric spectra (red) and bottom pressure spectra (white) are nearly invariant with latitude. Much ζ variability can be represented by a seasonal cycle and linear trend, plus a few EOFs that can be associated with known modes of climate variability and/or with topographic controls. Both wind and buoyancy forcing are important. The response is primarily basin-bound in nature, but uneven patterns of propagation across basin boundaries are clearly present, with the Pacific being able to affect large portions of the Indian and Atlantic basins, but the Atlantic affecting mostly the Arctic.

  17. 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

  18. 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.

  19. 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

  20. Effect of high CO/sub 2/ on growth and carbohydrate partitioning in pea (Pisum sativum L. ) plants

    SciTech Connect

    Potter, J.R.

    1986-04-01

    Beginning at 10 days of age, pea plants were exposed to air with normal (350 ppm) or high (1200 ppm) CO/sub 2/ levels until the plants were 20 days old. Growth was exponential between 10 and 20 days regardless of CO/sub 2/ treatment, and relative growth rates (RGR) under normal and high CO/sub 2/ were 0.20 and 0.24 g x g/sup -1/ x day/sup -1/ respectively. Also high CO/sub 2/ stimulated net assimilation rates (NAR) about 34%. While high CO/sub 2/ did not affect partitioning of dry matter into root, stem, or leaf mass, it decreased the partitioning of new dry matter into new leaf area by 12%, hence the failure of high CO/sub 2/ to stimulate RGR as much as it stimulated NAR. This decrease in partitioning into new leaf area elicited by high CO/sub 2/ was due mainly to the continuous accumulation of leaf starch which reached nearly 3.0 mg x cm/sup -2/. However, this accumulation of starch was not associated with a decline in NAR or photosynthesis. Even for high CO/sub 2/ treatments, transport of photosynthate during photoperiods greatly exceeded the rate necessary to deplete leaf starch during the dark period, indicating that there is unused transport capacity.

  1. 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

  2. Live Cell Interferometry Quantifies Dynamics of Biomass Partitioning during Cytokinesis

    PubMed Central

    Zangle, Thomas A.; Teitell, Michael A.; Reed, Jason

    2014-01-01

    The equal partitioning of cell mass between daughters is the usual and expected outcome of cytokinesis for self-renewing cells. However, most studies of partitioning during cell division have focused on daughter cell shape symmetry or segregation of chromosomes. Here, we use live cell interferometry (LCI) to quantify the partitioning of daughter cell mass during and following cytokinesis. We use adherent and non-adherent mouse fibroblast and mouse and human lymphocyte cell lines as models and show that, on average, mass asymmetries present at the time of cleavage furrow formation persist through cytokinesis. The addition of multiple cytoskeleton-disrupting agents leads to increased asymmetry in mass partitioning which suggests the absence of active mass partitioning mechanisms after cleavage furrow positioning. PMID:25531652

  3. Bacterial partition complexes segregate within the volume of the nucleoid.

    PubMed

    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

  4. 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.

  5. Crystal/liquid partitioning in augite - Effects of cooling rate

    NASA Technical Reports Server (NTRS)

    Gamble, R. P.; Taylor, L. A.

    1980-01-01

    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.

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

    PubMed

    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

    2015-04-01

    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, Na2S and Na2SO4) 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 Na2SO4 and Na2S 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 PbSO4(s) at low temperatures (<1000 K). The equilibrium calculation prediction also suggested that SiO2, CaO, TiO2, and Al2O3 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 concentration of Si, Ca and Al-containing compounds in the sludge. These findings provide useful information for understanding the partitioning behavior of Pb, facilitating the development of strategies to control the volatilization of Pb during sludge incineration. PMID:25554470

  7. Survivability, Partitioning, and Recovery of Enveloped Viruses in Untreated Municipal Wastewater.

    PubMed

    Ye, Yinyin; Ellenberg, Robert M; Graham, Katherine E; Wigginton, Krista R

    2016-05-17

    Many of the devastating pandemics and outbreaks of the 20th and 21st centuries have involved enveloped viruses, including influenza, HIV, SARS, MERS, and Ebola. However, little is known about the presence and fate of enveloped viruses in municipal wastewater. Here, we compared the survival and partitioning behavior of two model enveloped viruses (MHV and ϕ6) and two nonenveloped bacteriophages (MS2 and T3) in raw wastewater samples. We showed that MHV and ϕ6 remained infective on the time scale of days. Up to 26% of the two enveloped viruses adsorbed to the solid fraction of wastewater compared to 6% of the two nonenveloped viruses. Based on this partitioning behavior, we assessed and optimized methods for recovering enveloped viruses from wastewater. Our optimized ultrafiltration method resulted in mean recoveries (±SD) of 25.1% (±3.6%) and 18.2% (±9.5%) for the enveloped MHV and ϕ6, respectively, and mean recoveries of 55.6% (±16.7%) and 85.5% (±24.5%) for the nonenveloped MS2 and T3, respectively. A maximum of 3.7% of MHV and 2% of MS2 could be recovered from the solids. These results shed light on the environmental fate of an important group of viruses and the presented methods will enable future research on enveloped viruses in water environments. PMID:27111122

  8. The use of assemblage models to describe trace element partitioning, speciation, and fate: a review.

    PubMed

    Groenenberg, Jan E; Lofts, Stephen

    2014-10-01

    The fate of trace elements in soils, sediments, and surface waters is largely determined by their binding to reactive components, of which organic matter, metal oxides, and clays are considered most important. Assemblage models, combining separate mechanistic complexation models for each of the reactive components, can be used to predict the solid-solution partitioning and speciation of trace elements in natural environments. In the present review, the authors provide a short overview of advanced ion-binding models for organic matter and oxides and of their application to artificial and natural assemblages. Modeling of artificial assemblages of mineral components and organic matter indicates that the interactions between organic and mineral components are important for trace element binding, particularly for oxyanions. The modeling of solid-solution partitioning in natural systems is generally adequate for metal cations but less so for oxyanions, probably because of the neglect of organic matter-oxide interactions in most assemblage models. The characterization of natural assemblages in terms of their components (active organic matter, reactive oxide surface) is key to successful model applications. Improved methods for characterization of reactive components in situ will enhance the applicability of assemblage models. Collection of compositional data for soil and water archetypes, or the development of relationships to estimate compositions from geospatially available data, will further facilitate assemblage model use for predictive purposes. PMID:24862928

  9. New Linear Partitioning Models Based on Experimental Water: Supercritical CO2 Partitioning Data of Selected Organic Compounds.

    PubMed

    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. A total of 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 does the model built for the entire data set. PMID:27081725

  10. 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. PMID:25303663

  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. Selenium uptake by sulfur-accumulating bacteria

    NASA Astrophysics Data System (ADS)

    Nelson, Douglas C.; Casey, William H.; Sison, Jennette D.; Mack, E. Erin; Ahmad, Azeem; Pollack, Jeffrey S.

    1996-09-01

    Selenium is a trace metal in many rock-forming minerals but is a major environmental contaminant worldwide. Uptake of selenium by S-accumulating bacteria was examined in both pure cultures of Chromatium vinosum and in co-culture with Desulfovibrio desulfuricans. We used dual cultures including these bacteria to concentrate selenium into intracellular globules. The bacterium D. desulfuricans reduces sulfate [SO 42- (aq)] to sulfide [H 2S(aq)] and also reduces selenate [SeO 42- (aq)] to selenide [H 2Se (aq)]. Once reduced, sulfide is enzymatically oxidized and formed into intracellular globules by C. vinosum. We found that the selenium also forms an intercellular solid but the reaction is thermodynamically driven and proceeds by reducing S° (s) with H 2Se(aq). Relative to the initial molar ratio of selenate and sulfate in the medium, selenium is concentrated 4.5 to 32-fold in the globules. Because solid selenium is so much more stable than sulfur at growth conditions, other S-depositing bacteria, such as Beggiatoa and Chlorobium, should also concentrate selenium via this reaction, providing a strategy for eliminating contamination or for concentrating low natural levels into a usable form.

  13. IAEA activities in the area of partitioning and transmutation

    NASA Astrophysics Data System (ADS)

    Stanculescu, Alexander

    2006-06-01

    Four major challenges are facing the long-term development of nuclear energy: improvement of the economic competitiveness, meeting increasingly stringent safety requirements, adhering to the criteria of sustainable development, and public acceptance. Meeting the sustainability criteria is the driving force behind the topic of this paper. In this context, sustainability has two aspects: natural resources and waste management. IAEA's activities in the area of Partitioning and Transmutation (P&T) are mostly in response to the latter. While not involving the large quantities of gaseous products and toxic solid wastes associated with fossil fuels, radioactive waste disposal is today's dominant public acceptance issue. In fact, small waste quantities permit a rigorous confinement strategy, and mined geological disposal is the strategy followed by some countries. Nevertheless, political opposition arguing that this does not yet constitute a safe disposal technology has largely stalled these efforts. One of the primary reasons cited is the long life of many of the radioisotopes generated from fission. This concern has led to increased R&D efforts to develop a technology aimed at reducing the amount and radio-toxicity of long-lived radioactive waste through transmutation in fission reactors or sub-critical systems. In the frame of the Project on Technology Advances in Fast Reactors and Accelerator-Driven Systems (ADS), the IAEA initiated a number of activities on utilization of plutonium and transmutation of long-lived radioactive waste, ADS, and deuterium-tritium plasma-driven sub-critical systems. The paper presents past accomplishments, current status and planned activities of this IAEA project.

  14. Polychlorinated biphenyl accumulation in tree bark and wood growth rings

    SciTech Connect

    Meredith, M.L.; Hites, R.A.

    1987-07-01

    Polychlorinated biphenyls (PCBs) were found in the bark of black walnut and tulip poplar trees growing near a PCB-contaminated landfill. PCBs were also found in the bark of white oak trees growing 14 km away from the landfill. The concentration of individual congeners in the bark averaged 18 ppb at the landfill and 0.5 ppb at the other site. The PCB congeners were accumulated into the bark in proportion to their lipophilicity (as measured by octanol-water partition coefficients). The authors findings suggest that tree bark could be used for biomonitoring of lipophilic organic pollutants in the atmosphere. There is little evidence that PCBs are present in the wood of trees. The signal to blank ratios are always less than 3, and the relative concentrations between 20-year time intervals do not show trends that correlate with the known inputs of PCBs in Bloomington, IN. 2 tables.

  15. Proper symmetric and asymmetric endoplasmic reticulum partitioning requires astral microtubules.

    PubMed

    Smyth, Jeremy T; Schoborg, Todd A; Bergman, Zane J; Riggs, Blake; Rusan, Nasser M

    2015-08-01

    Mechanisms that regulate partitioning of the endoplasmic reticulum (ER) during cell division are largely unknown. Previous studies have mostly addressed ER partitioning in cultured cells, which may not recapitulate physiological processes that are critical in developing, intact tissues. We have addressed this by analysing ER partitioning in asymmetrically dividing stem cells, in which precise segregation of cellular components is essential for proper development and tissue architecture. We show that in Drosophila neural stem cells, called neuroblasts, the ER asymmetrically partitioned to centrosomes early in mitosis. This correlated closely with the asymmetric nucleation of astral microtubules (MTs) by centrosomes, suggesting that astral MT association may be required for ER partitioning by centrosomes. Consistent with this, the ER also associated with astral MTs in meiotic Drosophila spermatocytes and during syncytial embryonic divisions. Disruption of centrosomes in each of these cell types led to improper ER partitioning, demonstrating the critical role for centrosomes and associated astral MTs in this process. Importantly, we show that the ER also associated with astral MTs in cultured human cells, suggesting that this centrosome/astral MT-based partitioning mechanism is conserved across animal species. PMID:26289801

  16. Proper symmetric and asymmetric endoplasmic reticulum partitioning requires astral microtubules

    PubMed Central

    Smyth, Jeremy T.; Schoborg, Todd A.; Bergman, Zane J.; Riggs, Blake; Rusan, Nasser M.

    2015-01-01

    Mechanisms that regulate partitioning of the endoplasmic reticulum (ER) during cell division are largely unknown. Previous studies have mostly addressed ER partitioning in cultured cells, which may not recapitulate physiological processes that are critical in developing, intact tissues. We have addressed this by analysing ER partitioning in asymmetrically dividing stem cells, in which precise segregation of cellular components is essential for proper development and tissue architecture. We show that in Drosophila neural stem cells, called neuroblasts, the ER asymmetrically partitioned to centrosomes early in mitosis. This correlated closely with the asymmetric nucleation of astral microtubules (MTs) by centrosomes, suggesting that astral MT association may be required for ER partitioning by centrosomes. Consistent with this, the ER also associated with astral MTs in meiotic Drosophila spermatocytes and during syncytial embryonic divisions. Disruption of centrosomes in each of these cell types led to improper ER partitioning, demonstrating the critical role for centrosomes and associated astral MTs in this process. Importantly, we show that the ER also associated with astral MTs in cultured human cells, suggesting that this centrosome/astral MT-based partitioning mechanism is conserved across animal species. PMID:26289801

  17. Isotope-based evapotranspiration partition in semi-arid environments

    NASA Astrophysics Data System (ADS)

    Wang, Lixin; Parkes, Stephen; McCabe, Matthew; Azcurra, Cecilia; Wang, Jin; Graham, Peter

    2013-04-01

    Evapotranspiration (ET) partitioning is important for quantifying the water budget and understanding vegetation control on water cycles in various ecosystems. With the development of spectroscopy-based techniques for in-situ isotope measurements, the use of stable isotope based ET partition is rising rapidly. The sub-daily scale ET partition, however, is still rarely seen in the literature. In this study, we conducted an intensive field campaign measuring ET partition using laser-based isotope and chamber techniques in a pasture system between May and June 2012 in eastern Australia. Six soil collars were used, three of which had natural vegetation and the other three were bare soil collars where vegetation was artificially removed. The vegetated and bare soil collars were used to determine the isotopic composition of ET and evaporation, respectively. The isotopic composition of the transpiration flux was determined using a Licor leaf chamber for grasses inside the vegetated collars. The diurnal patterns in dET, dE and dT are observed. In the morning, they are depleted and became more enriched and level off during mid-day. Overall the total ET flux is dominated by evaporation, though transpiration contributions are relatively higher between 10am and 12pm. D-excess is a conservative tracer of ET components and may not be useful in ET partition. This study demonstrated the use of chamber-based measurements for direct partitioning of ET at sub-daily scale and showed a rarely observed diurnal pattern of ET partition.

  18. 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.

  19. Gas adsorption and accumulation on hydrophobic surfaces: Molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Luo, Qing-Qun; Yang, Jie-Ming

    2015-09-01

    Molecular dynamics simulations show that the gas dissolved in water can be adsorbed at a hydrophobic interface and accumulates thereon. Initially, a water depletion layer appears on the hydrophobic interface. Gas molecules then enter the depletion layer and form a high-density gas-enriched layer. Finally, the gas-enriched layer accumulates to form a nanobubble. The radian of the nanobubble increases with time until equilibrium is reached. The equilibrium state arises through a Brenner-Lohse dynamic equilibrium mechanism, whereby the diffusive outflux is compensated by an influx near the contact line. Additionally, supersaturated gas also accumulates unsteadily in bulk water, since it can diffuse back into the water and is gradually adsorbed by a solid substrate. Project supported by the National Natural Science Foundation of China (Grant No. 21376161).

  20. Analytical model for macromolecular partitioning during yeast cell division

    PubMed Central

    2014-01-01

    Background Asymmetric cell division, whereby a parent cell generates two sibling cells with unequal content and thereby distinct fates, is central to cell differentiation, organism development and ageing. Unequal partitioning of the macromolecular content of the parent cell — which includes proteins, DNA, RNA, large proteinaceous assemblies and organelles — can be achieved by both passive (e.g. diffusion, localized retention sites) and active (e.g. motor-driven transport) processes operating in the presence of external polarity cues, internal asymmetries, spontaneous symmetry breaking, or stochastic effects. However, the quantitative contribution of different processes to the partitioning of macromolecular content is difficult to evaluate. Results Here we developed an analytical model that allows rapid quantitative assessment of partitioning as a function of various parameters in the budding yeast Saccharomyces cerevisiae. This model exposes quantitative degeneracies among the physical parameters that govern macromolecular partitioning, and reveals regions of the solution space where diffusion is sufficient to drive asymmetric partitioning and regions where asymmetric partitioning can only be achieved through additional processes such as motor-driven transport. Application of the model to different macromolecular assemblies suggests that partitioning of protein aggregates and episomes, but not prions, is diffusion-limited in yeast, consistent with previous reports. Conclusions In contrast to computationally intensive stochastic simulations of particular scenarios, our analytical model provides an efficient and comprehensive overview of partitioning as a function of global and macromolecule-specific parameters. Identification of quantitative degeneracies among these parameters highlights the importance of their careful measurement for a given macromolecular species in order to understand the dominant processes responsible for its observed partitioning. PMID

  1. Maximum likelihood decoding analysis of Accumulate-Repeat-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    Repeat-Accumulate (RA) codes are the simplest turbo-like codes that achieve good performance. However, they cannot compete with Turbo codes or low-density parity check codes (LDPC) as far as performance is concerned. The Accumulate Repeat Accumulate (ARA) codes, as a subclass of LDPC codes, are obtained by adding a pre-coder in front of RA codes with puncturing where an accumulator is chosen as a precoder. These codes not only are very simple, but also achieve excellent performance with iterative decoding. In this paper, the performance of these codes with (ML) decoding are analyzed and compared to random codes by very tight bounds. The weight distribution of some simple ARA codes is obtained, and through existing tightest bounds we have shown the ML SNR threshold of ARA codes approaches very closely to the performance of random codes. We have shown that the use of precoder improves the SNR threshold but interleaving gain remains unchanged with respect to RA code with puncturing.

  2. Slip partitioning by elastoplastic propagation of oblique slip at depth.

    PubMed

    Bowman, David; King, Geoffrey; Tapponnier, Paul

    2003-05-16

    Oblique motion along tectonic boundaries is commonly partitioned into slip on faults with different senses of motion. The origin of slip partitioning is important to structural geology, tectonophysics, and earthquake mechanics. Partitioning can be explained by the upward elastoplastic propagation of oblique slip from a fault or shear zone at depth. The strain field ahead of the propagating fault separates into zones of predominantly normal, reverse, and strike-slip faulting. The model successfully predicts the distribution of fault types along parts of the San Andreas and Haiyuan faults. PMID:12750513

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Identifying Cognitive States Using Regularity Partitions

    PubMed Central

    2015-01-01

    Functional Magnetic Resonance (fMRI) data can be used to depict functional connectivity of the brain. Standard techniques have been developed to construct brain networks from this data; typically nodes are considered as voxels or sets of voxels with weighted edges between them representing measures of correlation. Identifying cognitive states based on fMRI data is connected with recording voxel activity over a certain time interval. Using this information, network and machine learning techniques can be applied to discriminate the cognitive states of the subjects by exploring different features of data. In this work we wish to describe and understand the organization of brain connectivity networks under cognitive tasks. In particular, we use a regularity partitioning algorithm that finds clusters of vertices such that they all behave with each other almost like random bipartite graphs. Based on the random approximation of the graph, we calculate a lower bound on the number of triangles as well as the expectation of the distribution of the edges in each subject and state. We investigate the results by comparing them to the state of the art algorithms for exploring connectivity and we argue that during epochs that the subject is exposed to stimulus, the inspected part of the brain is organized in an efficient way that enables enhanced functionality. PMID:26317983

  9. 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.

  10. 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.

  11. 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

  12. Cell Partition in Two Polymer Aqueous Phases

    NASA Technical Reports Server (NTRS)

    Brooks, D. E.

    1985-01-01

    In a reduced gravity environment the two polymer phases will not separate via density driven settling in an acceptably short length of time. It is to be expected that a certain amount of phase separation will take place, however, driven by the reduction in free energy gained when the interfacial area is reduced. This stage of separation process will therefore depend directly on the magnitude of the interfacial tension between the phases. In order to induce complete phase separation in a short time, electric field-induced separation which occurs because the droplets of one phase in the other have high electrophoretic mobilities which increase with droplet size was investigated. These mobilities are significant only in the presence of certain salts, particularly phosphates. The presence of such salts, in turn has a strong effect on the cell partition behavior in dextran-poly (ethylene glycol) (PEG) systems. The addition of the salts necessary to produce phase drop mobilities has a large effect on the interfacial tensions in the systems.

  13. 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. PMID:25187923

  14. 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

  15. Ecology: accumulating threats to life

    SciTech Connect

    Peterson, R.W.

    1980-04-01

    The accumulating impacts of toxic materials like polychloridnated bephenyls (PCBs), acid rain, deforestation in the Amazon River Basin, and nuclear energy are examined as life-threatening actions that the public must recognize. Immediate action is needed to abandon destructive human activities and search out those life-supporting choices which will replace immediate gratification with long-range benefits. (DCK)

  16. Pensions and Household Wealth Accumulation

    ERIC Educational Resources Information Center

    Engelhardt, Gary V.; Kumar, Anil

    2011-01-01

    Economists have long suggested that higher private pension benefits "crowd out" other sources of household wealth accumulation. We exploit detailed information on pensions and lifetime earnings for older workers in the 1992 wave of the Health and Retirement Study and employ an instrumental-variable (IV) identification strategy to estimate…

  17. Element partitioning in combustion- and gasification-based waste-to-energy units

    SciTech Connect

    Arena, Umberto; Di Gregorio, Fabrizio

    2013-05-15

    Highlights: ► Element partitioning of waste-to-energy units by means of a substance flow analysis. ► A comparison between moving grate combustors and high temperature gasifiers. ► Classification of key elements according to their behavior during WtE processes. ► Slags and metals from waste gasifiers are completely and immediately recyclable. ► Potential reduction of amounts of solid residue to be sent to landfill disposal. - Abstract: A critical comparison between combustion- and gasification-based waste-to-energy systems needs a deep knowledge of the mass flows of materials and elements inside and throughout the units. The study collected and processed data from several moving grate conventional incinerators and high-temperature shaft gasifiers with direct melting, which are in operation worldwide. A material and substance flow analysis was then developed to systematically assess the flows and stocks of materials and elements within each waste-to-energy unit, by connecting the sources, pathways, and intermediate and final sinks of each species. The patterns of key elements, such as carbon, chloride and heavy metals, in the different solid and gaseous output streams of the two compared processes have been then defined. The combination of partitioning coefficients with the mass balances on atomic species and results of mineralogical characterization from recent literatures was used to estimate a composition of bottom ashes and slags from the two types of waste-to-energy technologies. The results also allow to quantify some of the performance parameters of the units and, in particular, the potential reduction of the amount of solid residues to be sent to final disposal.

  18. 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.

  19. Light Remodels Lipid Biosynthesis in Nannochloropsis gaditana by Modulating Carbon Partitioning between Organelles.

    PubMed

    Alboresi, Alessandro; Perin, Giorgio; Vitulo, Nicola; Diretto, Gianfranco; Block, Maryse; Jouhet, Juliette; Meneghesso, Andrea; Valle, Giorgio; Giuliano, Giovanni; Maréchal, Eric; Morosinotto, Tomas

    2016-08-01

    The seawater microalga Nannochloropsis gaditana is capable of accumulating a large fraction of reduced carbon as lipids. To clarify the molecular bases of this metabolic feature, we investigated light-driven lipid biosynthesis in Nannochloropsis gaditana cultures combining the analysis of photosynthetic functionality with transcriptomic, lipidomic and metabolomic approaches. Light-dependent alterations are observed in amino acid, isoprenoid, nucleic acid, and vitamin biosynthesis, suggesting a deep remodeling in the microalgal metabolism triggered by photoadaptation. In particular, high light intensity is shown to affect lipid biosynthesis, inducing the accumulation of diacylglyceryl-N,N,N-trimethylhomo-Ser and triacylglycerols, together with the up-regulation of genes involved in their biosynthesis. Chloroplast polar lipids are instead decreased. This situation correlates with the induction of genes coding for a putative cytosolic fatty acid synthase of type 1 (FAS1) and polyketide synthase (PKS) and the down-regulation of the chloroplast fatty acid synthase of type 2 (FAS2). Lipid accumulation is accompanied by the regulation of triose phosphate/inorganic phosphate transport across the chloroplast membranes, tuning the carbon metabolic allocation between cell compartments, favoring the cytoplasm, mitochondrion, and endoplasmic reticulum at the expense of the chloroplast. These results highlight the high flexibility of lipid biosynthesis in N. gaditana and lay the foundations for a hypothetical mechanism of regulation of primary carbon partitioning by controlling metabolite allocation at the subcellular level. PMID:27325666

  20. Light Remodels Lipid Biosynthesis in Nannochloropsis gaditana by Modulating Carbon Partitioning between Organelles1[OPEN

    PubMed Central

    Vitulo, Nicola; Diretto, Gianfranco; Block, Maryse; Jouhet, Juliette; Meneghesso, Andrea; Valle, Giorgio; Giuliano, Giovanni; Maréchal, Eric

    2016-01-01

    The seawater microalga Nannochloropsis gaditana is capable of accumulating a large fraction of reduced carbon as lipids. To clarify the molecular bases of this metabolic feature, we investigated light-driven lipid biosynthesis in Nannochloropsis gaditana cultures combining the analysis of photosynthetic functionality with transcriptomic, lipidomic and metabolomic approaches. Light-dependent alterations are observed in amino acid, isoprenoid, nucleic acid, and vitamin biosynthesis, suggesting a deep remodeling in the microalgal metabolism triggered by photoadaptation. In particular, high light intensity is shown to affect lipid biosynthesis, inducing the accumulation of diacylglyceryl-N,N,N-trimethylhomo-Ser and triacylglycerols, together with the up-regulation of genes involved in their biosynthesis. Chloroplast polar lipids are instead decreased. This situation correlates with the induction of genes coding for a putative cytosolic fatty acid synthase of type 1 (FAS1) and polyketide synthase (PKS) and the down-regulation of the chloroplast fatty acid synthase of type 2 (FAS2). Lipid accumulation is accompanied by the regulation of triose phosphate/inorganic phosphate transport across the chloroplast membranes, tuning the carbon metabolic allocation between cell compartments, favoring the cytoplasm, mitochondrion, and endoplasmic reticulum at the expense of the chloroplast. These results highlight the high flexibility of lipid biosynthesis in N. gaditana and lay the foundations for a hypothetical mechanism of regulation of primary carbon partitioning by controlling metabolite allocation at the subcellular level. PMID:27325666