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1

Influence of solute-solvent coordination on the orientational relaxation of ion assemblies in polar solvents  

NASA Astrophysics Data System (ADS)

We have investigated the rotational dynamics of lithium thiocyanate (LiNCS) dissolved in various polar solvents with time and polarization resolved vibrational spectroscopy. LiNCS forms multiple distinct ionic structures in solution that can be distinguished with the CN stretch vibrational frequency of the different ionic assemblies. By varying the solvent and the LiNCS concentration, the number and type of ionic structures present in solution can be controlled. Control of the ionic structure provides control over the volume, shape, and dipole moment of the solute, critical parameters for hydrodynamic and dielectric continuum models of friction. The use of solutes with sizes comparable to or smaller than the solvent molecules also helps amplify the sensitivity of the measurement to the short-ranged solute-solvent interaction. The measured orientational relaxation dynamics show many clear and distinct deviations from simple hydrodynamic behavior. All ionic structures in all solvents exhibit multi-exponential relaxation dynamics that do not scale with the solute volume. For Lewis base solvents such as benzonitrile, dimethyl carbonate, and ethyl acetate, the observed dynamics strongly show the effect of solute-solvent complex formation. For the weak Lewis base solvent nitromethane, we see no evidence for solute-solvent complex formation, but still see strong deviation from the predictions of simple hydrodynamic theory.

Ji, Minbiao; Hartsock, Robert W.; Sung, Zheng; Gaffney, Kelly J.

2012-01-01

2

Weak Coordination as a Powerful Means for Developing Broadly Useful C-H Functionalization Reactions  

PubMed Central

Conspectus Reactions that convert carbon–hydrogen (C–H) bonds into carbon–carbon (C–C) or carbon–heteroatom (C–Y) bonds are attractive tools for organic chemists, potentially expediting the synthesis of target molecules through new disconnections in retrosynthetic analysis. Despite extensive inorganic and organometallic study of the insertion of homogeneous metal species into unactivated C–H bonds, practical applications of this technology in organic chemistry are still rare. Only in the past decade have metal-catalyzed C–H functionalization reactions become more widely utilized in organic synthesis. Research in the area of homogeneous transition metal–catalyzed C–H functionalization can be broadly grouped into two subfields. They reflect different approaches and goals and thus have different challenges and opportunities. One approach involves reactions of completely unfunctionalized aromatic and aliphatic hydrocarbons, which we refer to as “first functionalization.” Here the substrates are nonpolar and hydrophobic and thus interact very weakly with polar metal species. To overcome this weak affinity and drive metal-mediated C–H cleavage, chemists often use hydrocarbon substrates in large excess (for example, as solvent). Because highly reactive metal species are needed in first functionalization, controlling the chemoselectivity to avoid over-functionalization is often difficult. Additionally, because both substrates and products are comparatively low-value chemicals, developing cost-effective catalysts with exceptionally high turnover numbers that are competitive with alternatives (including heterogeneous catalysts) is challenging. Although an exciting field, first functionalization is beyond the scope of this Account. The second subfield of C–H functionalization involves substrates containing one or more pre-existing functional groups, termed “further functionalization.” One advantage of this approach is that the existing functional group (or groups) can be used to chelate the metal catalyst and position it for selective C–H cleavage. Precoordination can overcome the paraffin nature of C–H bonds by increasing the effective concentration of the substrate so that it needn't be used as solvent. From a synthetic perspective, it is desirable to use a functional group that is an intrinsic part of the substrate so that extra steps for installation and removal of an external directing group can be avoided. In this way, dramatic increases in molecular complexity can be accomplished in a single stroke through stereo- and site-selective introduction of a new functional group. Although reactivity is a major challenge (as with first functionalization), the philosophy in further functionalization differs—the major challenge is developing reactions that work with predictable selectivity in intricately functionalized contexts on commonly occurring structural motifs. In this Account, we focus on an emergent theme within the further functionalization literature: the use of commonly occurring functional groups to direct C–H cleavage through weak coordinations. We discuss our motivation for studying Pd-catalyzed C–H functionalization assisted by weakly coordinating functional groups and chronicle our endeavors to bring reactions of this type to fruition. Through this approach, we have developed reactions with a diverse range of substrates and coupling partners, with the broad scope likely stemming from higher reactivity of the less stable cyclopalladated intermediates held in place by weak coordinations.

Engle, Keary M.; Mei, Tian-Sheng; Wasa, Masayuki

2011-01-01

3

Coordinative Properties of Highly Fluorinated Solvents with Amino and Ether Groups  

PubMed Central

In spite of the widespread use of perfluorinated solvents with amino and ether groups in a variety of application fields, the coordinative properties of these compounds are poorly known. It is generally assumed that the electron withdrawing perfluorinated moieties render these functional groups rather inert, but little is known quantitatively about the extent of their inertness. This paper reports on the interactions between inorganic monocations and perfluorotripentylamine and 2H-perfluoro-5,8,11-trimethyl-3,6,9,12-tetraoxapentadecane, as determined with fluorous liquid-membrane cation-selective electrodes doped with tetrakis[3,5-bis(perfluorohexyl)phenyl]borate salts. The amine does not undergo measurable association with any ion tested, and its formal pKa is shown to be smaller than -0.5. This is consistent with the nearly planar structure of the amine at its nitrogen center, as obtained with density functional theory calculations. The tetraether interacts very weakly with Na+ and Li+. Assuming 1:1 stoichiometry, formal association constants were determined to be 2.3 and 1.5 M-1, respectively. This disproves an earlier proposition that the Lewis base character in such compounds may be non-existent. Due to the extremely low polarity of fluorous solvents and the resulting high extent of ion pair formation, a fluorophilic electrolyte salt with perfluoroalkyl substituents on both the cation and the anion had to be developed for these experiments. In its pure form, this first fluorophilic electrolyte salt is an ionic liquid with a glass transition temperature, Tg, of -18.5 °C. Interestingly, the molar conductivity of solutions of this salt increases very steeply in the high concentration range, making it a particularly effective electrolyte salt.

Boswell, Paul G.; Lugert, Elizabeth C.; Rabai, Jozsef; Amin, Elizabeth A.; Buhlmann, Philippe

2008-01-01

4

Coordinative properties of highly fluorinated solvents with amino and ether groups.  

PubMed

Despite the widespread use of perfluorinated solvents with amino and ether groups in a variety of application fields, the coordinative properties of these compounds are poorly known. It is generally assumed that the electron withdrawing perfluorinated moieties render these functional groups rather inert, but little is known quantitatively about the extent of their inertness. This paper reports on the interactions between inorganic monocations and perfluorotripentylamine and 2H-perfluoro-5,8,11-trimethyl-3,6,9,12-tetraoxapentadecane, as determined with fluorous liquid-membrane cation-selective electrodes doped with tetrakis[3,5-bis(perfluorohexyl)phenyl]borate salts. The amine does not undergo measurable association with any ion tested, and its formal pK(a) is shown to be smaller than -0.5. This is consistent with the nearly planar structure of the amine at its nitrogen center, as obtained with density functional theory calculations. The tetraether interacts very weakly with Na(+) and Li(+). Assuming 1:1 stoichiometry, formal association constants were determined to be 2.3 and 1.5 M(-1), respectively. This disproves an earlier proposition that the Lewis base character in such compounds may be nonexistent. Due to the extremely low polarity of fluorous solvents and the resulting high extent of ion pair formation, a fluorophilic electrolyte salt with perfluoroalkyl substituents on both the cation and the anion had to be developed for these experiments. In its pure form, this first fluorophilic electrolyte salt is an ionic liquid with a glass transition temperature, T(g), of -18.5 degrees C. Interestingly, the molar conductivity of solutions of this salt increases very steeply in the high concentration range, making it a particularly effective electrolyte salt. PMID:16316244

Boswell, Paul G; Lugert, Elizabeth C; Rábai, József; Amin, Elizabeth A; Bühlmann, Philippe

2005-12-01

5

Anions, solvents and spacer ligands assisted hydrogen-bonding coordination frameworks from tripodal ntb ligands  

NASA Astrophysics Data System (ADS)

Four new hydrogen-bonding (HB) coordination frameworks were synthesized and structurally characterized by using tris(2-benzimidazoylmethyl)amine (ntb) to react with different transition metal salts, which show diversified coordination motifs and hydrogen extending modes due to the contribution of counter-anions, methanol solvents, or spacer ligands, respectively. Among which, complexes 1 and 2 show mononuclear coordination units, connected by abundant N-H⋯N and N-H⋯O bonds formed between the units with trifluoromethanesulfonate (OTf -), azide ( N3-) anions or methanol solvents into 2D sheets, which are further connected by C-H⋯O or ?⋯? interactions into 3D topological nets; while in complexes 3 and 4, the spacer ligands 4-(pyridin-4-yl)pyridine (4'4-bipy) or 4,4'-bipyridine 1,1'-dioxide (dbpo) also participate in the coordination, resulting in either dinuclear coordination units linked by hydrogen-bonding into (4, 4) net or two different kinds of mononuclear units further extended by hydrogen-bonding into array of helical chains.

Pan, Mei; Lan, Mei-Hua; Jiang, Ji-Jun; Yang, Qing-Yuan; Su, Cheng-Yong

2010-09-01

6

Solvent wrapped metastable colloidal crystals: highly mutable colloidal assemblies sensitive to weak external disturbance.  

PubMed

Solvent wrapped "metastable" crystalline colloidal arrays (CCAs) have been prepared by supersaturation induced precipitation and self-assembly of monodisperse particles in polar/nonpolar organic solvents. These metastable CCAs possess ordered structures but with less stability comparing with traditionally fixed colloidal crystal systems. They are stabilized by the balance between long-range attraction and electrostatic repulsion of neighboring like-charged particles. Monitoring the reflection intensity during evaporation suggests that these crystals can exist for several hours at 90 °C and even longer at room temperature. Based on the evolution of particle volume fraction in whole suspension (?(SiO2)), crystal phase (?(crystal)), and liquid phase (?(liquid)), the formation of metastable CCAs can be understood as a microscopic phase separation process, where the homogeneous dispersion will separate into a "crystal phase" with orderly stacked particles and a "liquid phase" with randomly dispersed particles. Further calculation of the volume fraction of crystal phase (V(crystal)/V(total)) and the ratio of particles in crystal phase (f(crystal)) shows that with the increase of designed ?(SiO2), more particles precipitate to form colloidal crystals with larger sizes but the lattice spacing of the microcrystals remains constant. Unlike fixed or traditional responsive CCAs, these metastable CCAs can reversibly assemble and disassemble with great ease, because little energy is involved or required in this transformation. Therefore, they can sense weak external disturbances, including subtle motion and slight friction or shearing forces. PMID:24266836

Yang, Dongpeng; Ye, Siyun; Ge, Jianping

2013-12-11

7

Coordination structures and supramolecular architectures in a cerium(III)-malonamide solvent extraction system.  

PubMed

The process chemistry and solution structures investigated in the title system bridge the three ostensibly disparate fields of separation sciences, soft matter research, and coordination chemistry. We have explored this subject with synchrotron radiation research and advanced analyses leading to original insights into aggregation phenomena in solvent extraction. Herein we present findings showing the coagulation of reverse micelles into wormlike aggregates in organic phases (N,N'-dimethyl-N,N'-dibutyltetradecylmalonamide-abbreviated as DMDBTDMA-in n-dodecane) obtained by liquid-liquid extraction following contact with acidic and neutral aqueous media containing trivalent cerium. The growth of solute architectures was shown to prelude phase transition (i.e., the formation of a "third phase"). The presence of acid was shown to promote the growth of these micellar chains and, therefore, promoted third-phase formation. Acid was also shown to hydrate and swell the reverse micelle units, preorganizing them to allow for incorporation of cerium, leading to different coordination structures and enhanced metal extraction. The approach of linking both the coordination environment and supramolecular structures to the process properties of a solvent extraction system in a single study provides perspectives that are not available from independent, uncorrelated experimentation. Moreover, the analysis of small-angle X-ray scattering data from a solvent extraction system using the generalized indirect Fourier transform method to gain real-space information led to insights not otherwise available, showing that micellar assemblies are larger and more ordered than previously thought. This multipronged and multidisciplinary investigation opens new avenues in the evolving understanding of solute architectures in organic phases of practical relevance to solvent extraction and, simultaneously, of fundamental relevance to structured fluids and, in particular, phase transition phenomena. PMID:22420768

Ellis, Ross J; Antonio, Mark R

2012-04-10

8

Modulation of electronics and thermal stabilities of photochromic phosphino-aminoazobenzene derivatives in weak-link approach coordination complexes.  

PubMed

A series of d(8) transition-metal (Pt(II) and Pd(II)) coordination complexes incorporating phosphine-functionalized aminoazobenzene derivatives as hemilabile phosphino-amine (P,N) ligands were synthesized and studied as model weak-link approach (WLA) photoresponsive constructs. The optical and photochemical properties of these complexes were found to be highly influenced by various tunable parameters in WLA systems, which include type of metal, coordination mode, type of ancillary ligand, solvent, and outer-sphere counteranions. In dichloromethane, reversible chelation and partial displacement of the P,N coordinating moieties allow for toggling between aminoazobenzene- or pseudostilbene- and azobenzene-type derivatives. The reversible switching between electronic states of azobenzene can be controlled through either addition or extraction of chloride counterions and is readily visualized in the separation between ?-?* and n-?* bands in the complexes' electronic spectra. In acetonitrile solution, the WLA variables inherent to semiopen complexes have a significant impact on the half-lives of the corresponding cis isomers, allowing one to tune their half-lives from 20 to 21000 s, while maintaining photoisomerization behaviors with visible light. Therefore, one can significantly increase the thermal stability of a cis-aminoazobenzene derivative to the extent that single crystals for X-ray diffraction analysis can be grown for the first time, uncovering an unprecedented edge-to-face arrangement of the phenyl rings in the cis isomer. Overall, the azobenzene-functionalized model complexes shed light on the design parameters relevant for photocontrolled WLA molecular switches, as well as offer new ways of tuning the properties of azobenzene-based, photoresponsive materials. PMID:24187977

Park, Jung Su; Lifschitz, Alejo M; Young, Ryan M; Mendez-Arroyo, Jose; Wasielewski, Michael R; Stern, Charlotte L; Mirkin, Chad A

2013-11-13

9

Solvent effects in weak electrolytes. I. Effect of a hard sphere solvent on the sticky electrolyte model with L=?  

Microsoft Academic Search

The Ornstein–Zernike (OZ) equations are solved for the sticky electrolyte model (SEM) with a hard sphere solvent using the hypernetted chain (HNC) approximation for the stickiness and the mean spherical (MS) approximation for the electrical interactions. Relations among the coefficients of Baxter’s q functions and the equation for the excess internal energy are given in the MS approximation for L??,

Jayendran C. Rasaiah; Jianjun Zhu; Song Hi Lee

1989-01-01

10

Effects of solvent systems on two silver coordination complexes: From discrete structure to 2D sheet  

NASA Astrophysics Data System (ADS)

Two mixed-ligand silver(I) coordination complexes (CCs), [Ag4(mpyz)(npt)2·(H2O)2]n (1) and [Ag4(mpyz) (npt)2]n (2) were synthesized with reactions of methyl-pyrazine(mpyz) and 3-nitro-1,2-benzenedicarboxylic acid (H2npt) with silver nitrate in different solvent systems and were structurally characterized by single-crystal X-ray crystallography. Structural differences of CCs are due to the effects of solvent systems and the intricacy of the self-assembly process for these systems. For 1, the Ag4 unit which is like Y letter which stand upside and down and repeat to form a 1D-63-silver-ring which shares Ag1 and Ag2 only with npt ligands. The eight Ag ions of complex 2 are in a shape like the branches of a tree which repeat to form a 1D silver chain. Effects of solvents on the structures, as well as the intricacy of the self-assembly process were discussed. The photoluminescence, infrared spectroscopy (IR) and thermogravimetric analyses (TGA) behaviors of the compounds were also discussed.

Wang, Dan-Feng; Wang, Zhan-Hui; Lu, Bo-Wei; Chen, Shu-Fen; Zhang, Ting; Huang, Rong-Bin; Zheng, Lan-Sun

2014-02-01

11

Synthesis and Structural Characterization of Magnesium Based Coordination Networks in Different Solvents  

SciTech Connect

Three magnesium based metal-organic frameworks, Mg{sub 3}(3,5-PDC){sub 3}(DMF){sub 3} {center_dot} DMF [1], Mg(3,5-PDC)(H{sub 2}O) {center_dot} (H{sub 2}O) [3], and Mg4(3,5-PDC)4(DMF){sub 2}(H{sub 2}O){sub 2} {center_dot} 2DMF {center_dot} 4.5H{sub 2}O [4], and a 2-D coordination polymer, [Mg(3,5-PDC)(H{sub 2}O){sub 2}] [2] [PDC = pyridinedicarboxylate], were synthesized using a combination of DMF, methanol, ethanol, and water. Compound 1 [space group P2{sub 1}/n, a = 12.3475(5) {angstrom}, b = 11.1929(5) {angstrom}, c = 28.6734(12) {angstrom}, {beta} = 98.8160(10){sup o}, V = 3916.0(3) {angstrom}{sup 3}] consists of a combination of isolated and corner-sharing magnesium octahedra connected by the organic linkers to form a 3-D network with a 12.2 {angstrom} x 4.6 {angstrom} 1-D channel. The channel contains coordinated and free DMF molecules. In compound 2 [space group C2/c, a = 9.964(5) {angstrom}, b = 12.0694(6) {angstrom}, c = 7.2763(4) {angstrom}, {beta} = 106.4970(6){sup o}, V = 836.70(6) {angstrom}{sup 3}], PDC connects isolated seven coordinated magnesium polyhedra into a layered structure. Compound 3 [space group P6{sub 1}22, a = 11.479(1) {angstrom}, c = 14.735(3) {angstrom}, V = 1681.7(4) {angstrom}{sup 3}] (previously reported) contains isolated magnesium octahedra connected by the organic linker with each other forming a 3D network. Compound 4 [space group P2{sub 1}/c, a = 13.7442(14) {angstrom}, b = 14.2887(15) {angstrom}, c = 14.1178(14) {angstrom}, {beta} = 104.912(2){sup o}, V = 2679.2(5) {angstrom}{sup 3}] also exhibits a 3D network based on isolated magnesium octahedra with square cavities containing both disordered DMF and water molecules. The structural topologies originate due to the variable coordination ability of solvent molecules with the metal center. Water molecules coordinate with the magnesium metal centers preferably over other polar solvents (DMF, methanol, ethanol) used to synthesize the coordination networks. Despite testing multiple desolvation routes, we were unable to measure BET surface areas greater than 51.9 m{sup 2}/g for compound 1.

Banerjee, Debasis; Finkelstein, Jeffrey; Smirnov, A.; Forster, Paul M.; Borkowski, Lauren A.; Teat, Simon J.; Parise, John B. (UNLV); (SUNYB); (LBNL)

2012-10-11

12

Synthesis and Structural Characterization of Magnesium Based Coordination Networks in Different Solvents  

SciTech Connect

Three magnesium based metal-organic frameworks, Mg{sub 3}(3,5-PDC){sub 3}(DMF){sub 3} {center_dot} DMF [1], Mg(3,5-PDC)(H{sub 2}O) {center_dot} (H{sub 2}O) [3], and Mg{sub 4}(3,5-PDC){sub 4}(DMF){sub 2}(H{sub 2}O){sub 2} {center_dot} 2DMF {center_dot} 4.5H{sub 2}O [4], and a 2-D coordination polymer, [Mg(3,5-PDC)(H{sub 2}O){sub 2}] [2] [PDC = pyridinedicarboxylate], were synthesized using a combination of DMF, methanol, ethanol, and water. Compound 1 [space group P2{sub 1}/n, a = 12.3475(5) {angstrom}, b = 11.1929(5) {angstrom}, c = 28.6734(12) {angstrom}, {beta} = 98.8160(10){sup o}, V = 3916.0(3) {angstrom}{sup 3}] consists of a combination of isolated and corner-sharing magnesium octahedra connected by the organic linkers to form a 3-D network with a 12.2 {angstrom} x 4.6 {angstrom} 1-D channel. The channel contains coordinated and free DMF molecules. In compound 2 [space group C2/c, a = 9.964(5) {angstrom}, b = 12.0694(6) {angstrom}, c = 7.2763(4) {angstrom}, {beta} = 106.4970(6){sup o}, V = 836.70(6) {angstrom}{sup 3}], PDC connects isolated seven coordinated magnesium polyhedra into a layered structure. Compound 3 [space group P6{sub 1}22, a = 11.479(1) {angstrom}, c = 14.735(3) {angstrom}, V = 1681.7(4) {angstrom}{sup 3}] (previously reported) contains isolated magnesium octahedra connected by the organic linker with each other forming a 3D network. Compound 4 [space group P2{sub 1}/c, a = 13.7442(14) {angstrom}, b = 14.2887(15) {angstrom}, c = 14.1178(14) {angstrom}, {beta} = 104.912(2){sup o}, V = 2679.2(5) {angstrom}{sup 3}] also exhibits a 3D network based on isolated magnesium octahedra with square cavities containing both disordered DMF and water molecules. The structural topologies originate due to the variable coordination ability of solvent molecules with the metal center. Water molecules coordinate with the magnesium metal centers preferably over other polar solvents (DMF, methanol, ethanol) used to synthesize the coordination networks. Despite testing multiple desolvation routes, we were unable to measure BET surface areas greater than 51.9 m{sup 2}/g for compound 1.

D Banerjee; J Finkelstein; A Smirnov; P Forster; L Borkowski; S Teat; J Parise

2011-12-31

13

Deformed Coordinate-Space Hartree-Fock-Bogoliubov Approach to Weakly Bound Nuclei and Large Deformations  

SciTech Connect

The coordinate space formulation of the Hartree-Fock-Bogoliubov (HFB) method enables self-consistent treatment of mean field and pairing in weakly bound systems whose properties are affected by the particle continuum space. Of particular interest are neutron-rich, deformed drip-line nuclei which can exhibit novel properties associated with neutron skin. To describe such systems theoretically, we developed an accurate 2D lattice Skyrme-HFB solver HFB-AX based on B-splines. Compared to previous implementations, we made a number of improvements aimed at boosting the solver's performance. These include: explicit imposition of axiality and space inversion, use of the modified Broyden's method to solve self-consistent equations, and a partial parallelization of the code. HFB-AX has been benchmarked against other HFB solvers, both spherical and deformed, and the accuracy of the B-spline expansion was tested by employing the multi-resolution wavelet method. Illustrative calculations are carried out for stable and weakly bound nuclei at spherical and very deformed shapes, including constrained fission pathways. In addition to providing new physics insights, HFB-AX can serve as a useful tool to assess the reliability and applicability of coordinate-space and configuration-space HFB solvers, both existing and in development.

Pei, Junchen [ORNL; Stoitsov, M. V. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Fann, G. I. [Oak Ridge National Laboratory (ORNL); Nazarewicz, W. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Schunck, N. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Xu, F. R. [Peking University

2008-01-01

14

Molecular dynamics study of the weakly solvent dependent relaxation dynamics following chlorine dioxide photoexcitation  

NASA Astrophysics Data System (ADS)

The solvation dynamics following photoexcitation of chlorine dioxide (OClO) in different solvents are investigated by classical molecular dynamics. Following previous work on the aqueous response to OClO photoexcitation [J. Chem. Phys. 118, 4563 (2003)], the present study considers the response of chloroform and cyclohexane; these three liquids present unique solvent environments that differ significantly in both polarity and structure. The study is designed to ascertain the origin of the solvent-invariant homogeneous linewidth associated with OClO photoexcitation and to confirm, at the molecular level, whether the relaxation dynamics are similar across dissimilar solvents due to chance or a common relaxation origin. The results obtained here are used to predict the time scale of solvent-induced optical dephasing, and excellent agreement with experiment is observed for all solvents. Analysis demonstrates that the solvation dynamics of OClO are dominated by short-ranged mechanical solute-solvent interactions regardless of the identity and electrostatic properties of the solvent. Low-frequency translational motions dominate the coupling spectrum, and virtually no contribution to energy gap relaxation is achieved through intramolecular solvent motions. The invariant homogeneous linewidth is attributed to the similarity in the primary response of all solvents to OClO photoexcitation.

Brooksby, Craig; Prezhdo, Oleg V.; Reid, Philip J.

2003-11-01

15

WBC-ALC: A Weak Blocking Coordinated Application-Level Checkpointing for MPI Programs  

NASA Astrophysics Data System (ADS)

As supercomputers increase in size, the mean time between failures (MTBF) of a system becomes shorter, and the reliability problem of supercomputers becomes more and more serious. MPI is currently the de facto standard used to build high-performance applications, and researches on the fault tolerance methods of MPI are always hot topics. However, due to the characteristics of MPI programs, most current checkpointing methods for MPI programs need to modify the MPI library (even operating system), or implement a complicated protocol by logging lots of messages. In this paper, we carry forward the idea of Application-Level Checkpointing (ALC). Based on the general fact that programmers are familiar with the communication characteristics of applications, we have developed BC-ALC, a new portable blocking coordinated ALC for MPI programs. BC-ALC neither modifies the MPI library (even operating system) nor logs any message. It implements coordination only by the Barrier operations instead of any complicated protocol. Furthermore, in order to reduce the cost of fault-tolerance, we reduce the synchronization range of the barrier, and design WBC-ALC, a weak blocking coordinated ALC utilizing group synchronization instead of global synchronization based on the communication relationship between processes. We also propose a fault-tolerance framework developed on top of WBC-ALC and discuss an implementation of it. Experimental results on NPB3.3-MPI benchmarks validate BC-ALC and WBC-ALC, and show that compared with BC-ALC, the average coordination time and the average backup time of a single checkpoint in WBC-ALC are reduced by 44.5% and 5.7% respectively.

Xu, Xinhai; Yang, Xuejun; Lin, Yufei

16

Coordination of weakly binding anions to [Ru2(?-O2CCH3)4]+ in aqueous solution  

NASA Astrophysics Data System (ADS)

Four new complexes involving the diruthenium(II,III) tetraacetate core, [Ru2(?-O2CCH3)4]+, with three relatively weakly binding anions ClO4-, NO3- and CFCO2- have been synthesized and structurally characterized in exclusively aqueous media. Despite their low, but still positive, apparent donor numbers (D.N.) in water (according to previous literature by Linert et al.) both NO3- (D.N. = 0.21) and CFCO2- (D.N. < 8.65) do coordinate axially to [Ru2(?-O2CCH3)4]+ , with water having a D.N. = 19.5. NO3- forms both a polymer, [Ru2(?-O2CCH3)4(NO3)]x, and a mixed axial adduct with water, [Ru2(?-O2CCH3)4(H2O)(NO3)] depending on reaction stoichiometry. CFCO2- forms a double salt of the form [Ru2(?-O2CCH3)4(H2O)2] [Ru2(?-O2CCH3)4(CF3COO)2]⋯2H2O. ClO4-, with a negative apparent D.N. in water of -12.4, only "binds" outer-sphere to form [Ru2(?-O2CCH3)4(H2O)2](ClO4), at all reaction stoichiometries (as does the PF6- ion whose structure was also determined and found to be the same as a previous result). These results are compared to the very limited data of [Ru2(?-O2CCH3)4]+ adduct salts in aqueous solution and it is concluded that despite the low donor numbers, as long as they are positive, the species formed in water can be every bit as varied and rich as those formed in other solvents.

Dunlop, Kate; Wang, Ruiyao; Stanley Cameron, T.; Aquino, Manuel A. S.

2014-01-01

17

Metal ions and solvents ratio co-regulate four new magnetic coordination polymers based upon an unsymmetric tricarboxylate acid ligand.  

PubMed

Four new coordination polymers (CPs), [Co3(L)2(bib)3(EtOH)2]·2H2O (), [Mn3(L)2(bib)2(H2O)4]·4H2O (), [Ni(HL)(bib)(H2O)3] () and [Ni3(bib)4(H2O)10]·2(L)·12(H2O) (), were synthesized under solvothermal conditions with an unsymmetrical tricarboxylic acid ligand [biphenyl-3,3',5-tricarboxylic acid (H3L)] in the presence of the 1,4-bis(1H-imidazol-4-yl)benzene (bib) ligand. In compound , tricarboxylate acid ligands (H3L) link Co centers to generate two-dimensional (2D) layers which are further connected by bib ligands to exhibit a three-dimensional (3D) framework with a (4,4,5)-connected (4(2)·6(3)·8)2(4(2)·6(7)·8)2(6(4)·8·10) topology. The three-dimensional (3D) framework of is defined as a (3,3,4)-connected topology with the point symbol of (6·8(2))2(6(2)·8)2(8·10(4)·12). Compound contains a one-dimensional (1D) left-hand helix chain along the a direction and further extends into a 2D supramolecular network and a 3D supramolecular framework via hydrogen bonds. Compound displays a one-dimensional (1D) molecular ladder, which is further combined with each other through ?? stacking to extend into 2D supramolecular sheets. The supramolecular networks of and resulted from the different solvent ratios [V(H2O)-V(EtOH)] in the reaction. All the CPs are characterized by single-crystal X-ray diffraction analyses, powder X-ray diffraction (PXRD), elemental analyses, IR spectroscopy, and TGA analyses. Moreover, the weak ferromagnetic properties of and and antiferromagnetic properties of and have also been investigated. PMID:24905184

Li, Yuan-Pu; Chai, Ying; Yang, Guo-Ping; Miao, Hui-Hui; Cui, Lin; Wang, Yao-Yu; Shi, Qi-Zhen

2014-06-24

18

Use of solvent to regulate the degree of polymerisation in weakly associated supramolecular oligomers.  

PubMed

Using a tetrathiafulvalene functionalised calix[4]pyrrole (TTF-C[4]P; ) and alkyl diester-linked bis-dinitrophenols (), it was found that the solvent polarity and linker length have an effect on the molecular aggregation behaviour. 2D (1)H NOESY, DOSY NMR and UV-vis-NIR spectroscopic studies, as well as single crystal X-ray diffraction analyses support these conclusions. PMID:24722903

Bähring, Steffen; Kim, Dong Sub; Duedal, Troels; Lynch, Vincent M; Nielsen, Kent A; Jeppesen, Jan O; Sessler, Jonathan L

2014-04-24

19

Can weakly coordinating anions stabilize mercury in its oxidation state +IV?  

PubMed

While the thermochemical stability of gas-phase HgF4 against F2 elimination was predicted by accurate quantum chemical calculations more than a decade ago, experimental verification of "truly transition-metal" mercury(IV) chemistry is still lacking. This work uses detailed density functional calculations to explore alternative species that might provide access to condensed-phase Hg(IV) chemistry. The structures and thermochemical stabilities of complexes Hg(IV)X4 and Hg(IV)F2X2 (X- = AlF4-, Al2F7-, AsF6-, SbF6-, As2F11-, Sb2F11-, OSeF5-, OTeF5-) have been assessed and are compared with each other, with smaller gas-phase HgX4 complexes, and with known related noble gas compounds. Most species eliminate F2 exothermically, with energies ranging from only about -60 kJ mol(-1) to appreciable -180 kJ mol(-1). The lower stability of these species compared to gas-phase HgF4 is due to relatively high coordination numbers of six in the resulting Hg(II) complexes that stabilize the elimination products. Complexes with AsF6 ligands appear more promising than their SbF6 analogues, due to differential aggregation effects in the Hg(II) and Hg(IV) states. HgF2X2 complexes with X- = OSeF5- or OTeF5- exhibit endothermic fluorine elimination and relatively weak interactions in the Hg(II) products. However, elimination of the peroxidic (OEF5)2 coupling products of these ligands provides an alternative exothermic elimination pathway with energies between -120 and -130 kJ mol(-1). While all of the complexes investigated here thus have one exothermic decomposition channel, there is indirect evidence that the reactions should exhibit nonnegligible activation barriers. A number of possible synthetic pathways towards the most interesting condensed-phase Hg(IV) target complexes are proposed. PMID:15736276

Riedel, Sebastian; Straka, Michal; Kaupp, Martin

2005-04-22

20

Investigations of iron coordination and redox reactions in seawater using 59Fe radiometry and ion-pair solvent extraction of amphiphilic iron complexes  

Microsoft Academic Search

Hudson, R.J.M., Covault, D.T. and Morel, F.M.M., 1992. Investigations of iron coordination and redox reactions in seawater using 59Fe radiometry and ion-pair solvent extraction of amphiphilic iron complexes. Mar. Chem., 38: 209-235. Iron coordination and redox reactions in synthetic and coastal seawater were investigated at na- nomolar concentrations using 59Fe radiometry and ion-pair solvent extraction of iron chelated by sulfoxine

Robert J. M. Hudson; Dianne T. Covault; Francois M. M. Morel

1992-01-01

21

Continuum Hartree-Fock-Bogoliubov theory for weakly bound deformed nuclei using the coordinate-space Green's function method  

SciTech Connect

We formulate a new scheme of the Hartree-Fock-Bogoliubov mean-field theory applicable to weakly bound and pair-correlated deformed nuclei using the coordinate-space Green's function technique. On the basis of a coupled-channel representation of the quasiparticle wave function expanded in terms of the partial waves, we impose the correct boundary condition of the asymptotically out-going waves on the continuum quasiparticle states. We perform numerical analysis for {sup 38}Mg to illustrate properties of the continuum quasiparticle states and the pair correlation in deformed nuclei near the neutron drip line.

Oba, Hiroshi [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Matsuo, Masayuki [Department of Physics, Faculty of Science, Niigata University, Niigata 950-2181 (Japan)

2009-08-15

22

Coordinates  

NSDL National Science Digital Library

This introduction to the labeling of points on a plane by their Cartesian coordinates can optionally be extended to coordinates in 3-dimensional space, to plane polar coordinates and to 3-dimensional polar coordinates. Students should learn to use Cartesian coordinates (x,y) for defining the position of a point in two dimensions and to use Cartesian coordinates (x,y,z) in 3-dimensional space and learn to appreciate the two ways of defining the z axis. Students should also become familiar with some of the tools and terms used by surveyors such as theodolite, azimuth, elevation, and zenith. Optional items for students familiar with trigonometry and with the theorem of Pythagoras are polar coordinates (r,f ) on the plane, Converting (r,f) to (x,y) and vice versa, at least for r, and Spherical polar coordinates (r,q, f) in 3-dimensional space.

Stern, David

23

Calorimetric study on coordination of tridentate imidazolyl calix[6]arene ligands to zinc ion in organic solvents.  

PubMed

Complexation of three kinds of tris(imidazolyl)calix[6]arenes containing alternate p-substituents (Calix-tBu, R(1) = R(2) = tert-butyl; Calix-NH(2), R(1) = tert-butyl, R(2) = NH(2); Calix-NO(2), R(1) = tert-butyl, R(2) = NO(2)) with Zn(ClO(4))(2)(H(2)O)(6) in acetonitrile, methanol, and THF was investigated via isothermal titration calorimetry (ITC). For the coordination of these calixarene ligands to Zn(II) in acetonitrile, typical one-phase exothermic titration curves were obtained, indicating the formation of 1:1 ligand-Zn(II) complexes accompanied by large conformational changes of the ligands. In contrast, the complexation in methanol was endothermic and dominated by favorable entropy changes. The entropy gains were achieved by extensive desolvation from both Zn(II) and the ligands. ITC measurements suggest a 2:1 ligand-Zn(II) complex formation in THF in the presence of excess ligands (Calix-NH(2) and Calix-NO(2)). The 2:1 complexes were converted to 1:1 complexes upon further addition of Zn(ClO(4))(2)(H(2)O)(6). The results indicate the important role of a coordinating solvent (acetonitrile) for direct formation of the 1:1 complexes under the conditions of excess ligand. Complexation of a ditopic ligand (Calix-Tri) with three triazole moieties on the wider rim was also studied via ITC. The first coordination of the imidazole moieties to Zn(II) was an exothermic process. This was followed by the entropically favorable coordination of the triazole moieties to the divalent cation. We have also investigated exchange of the fourth ligand (H(2)O) of the Zn(II) complex of Calix-NH(2) with butylamine, heptylamine, acetonitrile, and acetamide in a noncompetitive solvent, THF. The ?H(0) tended to decrease upon increasing the electron-pair-donating ability of the guest ligand, whereas it was also affected by an entropic term due to restricted rotation of the guest ligand inside the calixarene cavity. PMID:21648400

Kano, Koji; Kondo, Masataka; Inoue, Haruka; Kitagishi, Hiroaki; Colasson, Benoit; Reinaud, Olivia

2011-07-01

24

Solvent-mediated crystal-to-crystal interconversion between discrete lanthanide complexes and one-dimensional coordination polymers and selective sensing for small molecules.  

PubMed

Two isostructural 1D coordination polymers {[Ln(OAc)2(H2O)(OBPT)]·3H2O}n (HOBPT = 4,6-bis(2-pyridyl)-1,3,5-triazin-2-ol, Ln = Eu(3+), 1; Tb(3+), 3) and two discrete complexes [Ln(OAc)2(DMF)2(OBPT)] (Ln = Eu(3+), 2; Tb(3+), 4) have been synthesized in H2O-MeOH or DMF solvents, respectively. Their structures were identified by powder X-ray diffraction. Single-crystal X-ray studies for complexes 1 and 2 revealed that the coordination geometries of the Eu(3+) ions are similar and can be described as a distorted tricapped trigonal prism with six oxygen atoms and three nitrogen atoms. The difference between them is that one aqua ligand and one oxygen atom from the OBPT ligand complete the coordination sphere in complex 1, whereas two DMF molecules complete the coordination sphere in complex 2. Interestingly, the solvent-mediated, reversible crystal-to-crystal transformation between them was achieved by immersing the crystalline samples in the corresponding solvent (H2O or DMF) or by exposing them to solvent vapor. Complex 1 shows a highly selective luminescence enhancement in response to DMF in comparison to that observed in response to other examined solvents such as acetone, ethyl acetate, ethanol, acetonitrile, methanol, and THF. PMID:23697967

Wu, Jin-Ji; Ye, Yu-Xin; Qiu, Ying-Yu; Qiao, Zheng-Ping; Cao, Man-Li; Ye, Bao-Hui

2013-06-01

25

Electrophoretic mobility of weakly-charged (dipolar) hydrogels in water: contribution of hydrogen-bonding in the solvent dipole layer.  

PubMed

Counterintuitive observations by dynamic light-scattering experiments of negative electrophoretic mobility in uncharged, lightly charged, and later, densely-charged hydrogel nanoparticles are presented. A tentative theory, emphasizing the roles of electric field energy density and induced dipole moments in the dipolar and hydrogen-bonding solvent layer surrounding the particle, is introduced to explain and rationalize these observations. Addition of co-solvent glycine seems to produce a Kohlrausch boundary regulating effect which again illustrates the importance of the dipole layer and hydrogen bonds within it. Further alternative theories involving electric field gradients are discussed which may be relevant to other uncharged systems (such as gold nanoparticles). A contribution to the dipolar solvent-induced mobility is derived in Appendix A. A proposal for a new treatment of traditional (i.e. charged colloid particle) electrokinetic phenomena is given in a second Appendix (Appendix B). PMID:24370434

Kirk, William; Wessels, William

2014-02-15

26

Micromolding of a Highly Fluorescent Reticular Coordination Polymer: Solvent-Mediated Reconfigurable Polymerization in a Soft Lithographic Mold  

SciTech Connect

Coordination polymerization of pyridine-based ligands and zinc or silver ions was controlled by soft lithographic micromolding in capillaries. The polymer patterns that are produced are highly fluorescent and supramolecularly structured.

Y You; H Yang; J Chung; J Kim; Y Jung; S Park

2011-12-31

27

Dynamic equilibria in solvent-mediated anion, cation and ligand exchange in transition-metal coordination polymers: solid-state transfer or recrystallisation?  

PubMed

The solution properties of a series of transition-metal-ligand coordination polymers [ML(X)(n)](infinity) [M=Ag(I), Zn(II), Hg(II) and Cd(II); L=4,4'-bipyridine (4,4'-bipy), pyrazine (pyz), 3,4'-bipyridine (3,4'-bipy), 4-(10-(pyridin-4-yl)anthracen-9-yl)pyridine (anbp); X=NO(3) (-), CH(3)COO(-), CF(3)SO(3) (-), Cl(-), BF(4) (-); n=1 or 2] in the presence of competing anions, metal cations and ligands have been investigated systematically. Providing that the solubility of the starting complex is sufficiently high, all the components of the coordination polymer, namely the anion, the cation and the ligand, can be exchanged on contact with a solution phase of a competing component. The solubility of coordination polymers is a key factor in the analysis of their reactivity and this solubility depends strongly on the physical properties of the solvent and on its ability to bind metal cations constituting the backbone of the coordination polymer. The degree of reversibility of these solvent-induced anion-exchange transformations is determined by the ratio of the solubility product constants for the starting and resultant complexes, which in turn depend upon the choice of solvent and the temperature. The extent of anion exchange is controlled effectively by the ratio of the concentrations of incoming ions to outgoing ions in the liquid phase and the solvation of various constituent components comprising the coordination polymer. These observations can be rationalised in terms of a dynamic equilibrium of ion exchange reactions coupled with Ostwald ripening of crystalline products. The single-crystal X-ray structures of [Ag(pyz)ClO(4)](infinity) (1), {[Ag(4,4'-bipy)(CF(3)SO(3))]CH(3)CN}(infinity) (2), {[Ag(4,4'-bipy)(CH(3)CN)]ClO(4) 0.5 CH(3)CN}(infinity) (3), metal-free anbp (4), [Ag(anbp)NO(3)(H(2)O)](infinity) (5), {[Cd(4,4'-bipy)(2)(H(2)O)(2)](NO(3))(2)4 H(2)O}(infinity) (6) and {[Zn(4,4'-bipy)SO(4)(H(2)O)(3)] 2 H(2)O}(infinity) (7) are reported. PMID:19630015

Cui, Xianjin; Khlobystov, Andrei N; Chen, Xinyong; Marsh, Dan H; Blake, Alexander J; Lewis, William; Champness, Neil R; Roberts, Clive J; Schröder, Martin

2009-09-01

28

Part I. Student success in intensive versus traditional introductory chemistry courses. Part II. Synthesis of salts of the weakly coordinating trisphat anion  

NASA Astrophysics Data System (ADS)

Part I. Intensive courses have been shown to be associated with equal or greater student success than traditional-length courses in a wide variety of disciplines and education levels. Student records from intensive and traditional-length introductory general chemistry courses were analyzed to determine the effects, of the course format, the level of academic experience, life experience (age), GPA, academic major and gender on student success in the course. Pretest scores, GPA and ACT composite scores were used as measures of academic ability and prior knowledge; t-tests comparing the means of these variables were used to establish that the populations were comparable prior to the course. Final exam scores, total course points and pretest-posttest differences were used as measures of student success; t-tests were used to determine if differences existed between the populations. ANCOVA analyses revealed that student GPA, pretest scores and course format were the only variables tested that were significant in accounting for the variance of the academic success measures. In general, the results indicate that students achieved greater academic success in the intensive-format course, regardless of the level of academic experience, life experience, academic major or gender. Part II. Weakly coordinating anions have many important applications, one of which is to function as co-catalysts in the polymerization of olefins by zirconocene. The structure of tris(tetrachlorobenzenedialato) phosphate(V) or "trisphat" anion suggests that it might be an outstanding example of a weakly coordinating anion. Trisphat acid was synthesized and immediately used to prepare the stable tributylammonium trisphat, which was further reacted to produce trisphat salts of Group I metal cations in high yields. Results of the 35Cl NQR analysis of these trisphat salts indicate only very weak coordination between the metal cations and the chlorine atoms of the trisphat anion.

Hall, Mildred V.

29

Synthesis of the salts of weakly coordination stibate ions & Students' perceptions of two- and three-dimensional animations depicting an oxidation-reduction reaction  

NASA Astrophysics Data System (ADS)

SYTHESIS OF SALTS OF WEAKLY COORDINATING STIBATE IONS. Weakly coordinating anions have many important applications including olefin polymerization co-catalysis. In an attempt to make tristibic acid, distibic acid and tetrastibic acid were made. Cesium, barium, nickel(II), and diethylammonium salts of tetrastibic acid were also synthesized. Tetrastibic acid and the ammonium salts were concluded to be stable. Elemental analyses showed that neither tristibic acid nor tristibic acid were stable under the reaction conditions employed. STUDENTS' PERCEPTIONS OF TWO- AND THREE-DIMENSIONAL ANIMATIONS DEPICTING AN OXIDATION-REDUCATION REACTION. Electrochemistry is a difficult subject for many students to comprehend. In order to improve teaching in this area of chemistry, semi-structured clinical interviews on second-semester introductory chemistry students were conducted in which students' were asked to explain the particulate behavior of the chemicals in an oxidation-reduction reaction. The interviews included questions after students viewed the chemical demonstration and two computer animations depicting the particulate nature of the same chemical reaction. Misinterpretations of the two animations were identified and described in detail. The simpler 2-D animation was beneficial in helping students understand the oxidation-reduction reaction and write the balanced chemical equation. However, the 3-D animation did not appear to be detrimental to student understanding. Suggestions, taken from the students' comments in the interviews, for improving the animations and for teaching electrochemistry were discussed.

Rosenthal, Deborah Renee

30

Co-ligand and Solvent Effects on the Spin-Crossover Behaviors of PtS-type Porous Coordination Polymers.  

PubMed

In our previous work ( Chen , X.-Y. ; Chem. Commun. 2013 , 49 , 10977 - 10979 ), we have reported the crystal structure and spin-crossover properties of a compound [Fe(NCS)2(tppm)]·S [1·S, tppm = 4,4',4?,4?-tetrakis(4-pyridylethen-2-yl)tetraphenylmethane, S = 5CH3OH·2CH2Cl2]. Here, its analogues [Fe(X)2(tppm)]·S [X = NCSe(-), NCBH3(-), and N(CN)2(-) for compounds 2·S, 3·S, and 4·S, respectively] have been synthesized and characterized by variable-temperature X-ray diffraction and magnetic measurements. The crystal structure analyses of 2·S and 3·S reveal that both compounds possess the same topologic framework (PtS-type) building from the tetrahedral ligand tppm and planar unit FeX2; the framework is two-fold self-interpenetrated to achieve one-dimensional open channels occupied by solvent molecules. Powder X-ray diffraction study indicates the same crystal structure for 4. The average values of Fe-N distances observed, respectively, at 100, 155, and 220 K for the Fe1/Fe2 centers are 1.969/2.011, 1.970/2.052, and 2.098/2.136 Å for 2·S, whereas those at 110, 175, and 220 K are 1.972/2.013, 1.974/2.056, and 2.100/2.150 Å for 3·S, indicating the presence of a two-step spin crossover in both compounds. Temperature-dependent magnetic susceptibilities (?MT) confirm the two-step spin-crossover behavior at 124 and 200 K in 2·S, 151 and 225 K in 3·S, and 51 and 126 K in 4·S, respectively. The frameworks of 2-4 are reproducible upon solvent exchange and thereafter undergo solvent-dependent spin-crossover behaviors. PMID:24779402

Chen, Xiang-Yi; Huang, Rong-Bin; Zheng, Lan-Sun; Tao, Jun

2014-05-19

31

Structural variation from 1D to 3D: effects of ligands and solvents on the construction of lead(II)-organic coordination polymers.  

PubMed

A series of Pb(II) coordination polymers [Pb(ndc)(dpp)] (1), [Pb(ndc)(ptcp)].0.5 H2O (2), [Pb(ndc)(dppz)] (3), [Pb(ndc)(tcpn)(2)] (4), [Pb2(ndc)2(tcpp)] (5), [Pb(Hndc)2].H2O (6), [Pb(ndc)(dma)] (7), [Pb(bdc)(dma)] (8), [Pb(trans-chdc)(H2O)] (9), and [Pb2(cis-chdc)2].NH(CH3)2 (10), where ndc=1,4-naphthalenedicarboxylate, dpp=4,7-diphenyl-1,10-phenanthroline, ptcp=2-phenyl-1H-1,3,7,8-tetraazacyclopenta[l]phenanthrene, dppz=dipyrido[3,2-a:2',3'-c]phenazine, tcpn=2-(1H-1,3,7,8-tetraazacyclopenta[l]phenanthren-2-yl)naphthol, tcpp=4-(1H-1,3,7,8-tetraazacyclopenta[l]phenanthren-2-yl)phenol, dma=N,N-dimethylacetamide, bdc=1,4-benzenedicarboxylate, and chdc=1,4-cyclohexanedicarboxylate, have been synthesized from a hydrothermal or solvothermal reaction system by varying the ligands or the solvents. Compounds 1-5 crystallize with an N-donor chelating ligand and an aromatic dicarboxylate linker. Compounds 1-4 are 1D polymers with different pi-pi stacking interactions, whereas compound 5 consists of 2D layers. The structures of compounds 7, 8, and 10 are 3D frameworks formed by connection of the Pb(II) centers by organic acid ligands. Compound 7 is chiral although the ndc ligand is achiral, while the framework of 8 is a typical 3D (3,4)-connected net. Compound 10 is the first example of Pb(II) wheel cluster [Pb(8)O(8)] units bridged by carboxylate groups. Compound 6 contains 1D chains which are further extended to a 3D structure by pi-pi interactions. Compound 9 consists of a 2D network constructed by Pb(II) centers and trans-chdc ligands. The structural differences between 7 and 8 and between 9 and 10 indicate the importance of solvents for framework formation of the coordination polymers. By varying the solvent the cis and trans conformations of H(2)chdc in 9 and 10 were separated completely. The photoluminescence and nonlinear optical properties of the coordination polymers have also been investigated. PMID:17212363

Yang, Jin; Li, Guo-Dong; Cao, Jun-Jun; Yue, Qi; Li, Guang-Hua; Chen, Jie-Sheng

2007-01-01

32

A facile route to synthesize chalcopyrite CuInSe2 nanocrystals in non-coordinating solvent  

NASA Astrophysics Data System (ADS)

A facile route for synthesizing CuInSe2 nanocrystals was developed using an alkanethiol as ligand and noncoordinating octadecene as solvent. The CuInSe2 nanoparticles and nanoplates were obtained, depending on the reaction temperature and time. When the reaction temperature was set at 180 °C and reaction for an hour, CuInSe2 nanoparticles with an average size of 6.2 nm were produced. As the reaction time was prolonged to 3 h, nanoplates appeared inside the nanoparticles. When the reaction temperature was elevated to 210 °C and reaction for 3 h, triangular or hexagonal CuInSe2 nanoplates with sharp edges were synthesized. It was proposed that the Ostwald ripening induced the morphology evolution of the CuInSe2 nanoparticles into nanoplates at the higher temperature. The nanoparticles and nanoplates were characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). The UV-vis absorption spectra of the CuInSe2 nanoparticles were significantly blue-shifted in comparison with the bulk material due to the quantum confinement.

Zhong, Haizheng; Li, Yunchao; Ye, Mingfu; Zhu, Zhongzheng; Zhou, Yi; Yang, Chunhe; Li, Yongfang

2007-01-01

33

Synthesis, structure and properties of a 3D plywood-like nickel(II) hexaazamacrocyclic coordination polymer constructed from weak Ni\\ctdot O interactions and hydrogen bonding  

NASA Astrophysics Data System (ADS)

A 3D plywood-like nickel(II) hexaazamacrocyclic coordination polymer {[Ni(hto)(H2btec]}n (2) (hto = 1,3,6,9,11,14-hexaazatricyclo[12.2.1.16,9]octadecane, H4btec = 1,2,4,5-benzenetetracarboxylic acid) was synthesized by a slow diffusion method and characterized by X-ray crystallography and spectroscopic methods. The structure of 2 is made up of [Ni(hto)]2+ cation and H2btec2- anion in a molecular ratio of 1:1. The nickel(II) ions in the complex are bridged by the H2btec2- ligand based on weak Ni⋯O coordination interactions to form a 1D chain. The alternate cross-like 1D chains are packed in a plywood-like structure and interconnected with each other by hydrogen bonding to form a 3D network. Complex 2 exhibits fluorescent emission in the solid state at room temperature.

Tao, Bo; Jiang, Xiang; Xia, Hua; Cheng, Hefa

2012-03-01

34

Magnetic properties of weakly exchange-coupled high spin Co(II) ions in pseudooctahedral coordination evaluated by single crystal X-band EPR spectroscopy and magnetic measurements.  

PubMed

We report single-crystal X-band EPR and magnetic measurements of the coordination polymer catena-(trans-(?2-fumarato)tetraaquacobalt(II)), 1, and the Co(II)-doped Zn(II) analogue, 2, in different Zn:Co ratios. 1 presents two magnetically inequivalent high spin S = 3/2 Co(II) ions per unit cell, named A and B, in a distorted octahedral environment coordinated to four water oxygen atoms and trans coordinated to two carboxylic oxygen atoms from the fumarate anions, in which the Co(II) ions are linked by hydrogen bonds and fumarate molecules. Magnetic susceptibility and magnetization measurements of 1 indicate weak antiferromagnetic exchange interactions between the S = 3/2 spins of the Co(II) ions in the crystal lattice. Oriented single crystal EPR experiments of 1 and 2 were used to evaluate the molecular g-tensor and the different exchange coupling constants between the Co(II) ions, assuming an effective spin S?= 1/2. Unexpectedly, the eigenvectors of the molecular g-tensor were not lying along any preferential bond direction, indicating that, in high spin Co(II) ions in roughly octahedral geometry with approximately axial EPR signals, the presence of molecular pseudo axes in the metal site does not determine preferential directions for the molecular g-tensor. The EPR experiment and magnetic measurements, together with a theoretical analysis relating the coupling constants obtained from both techniques, allowed us to evaluate selectively the exchange coupling constant associated with hydrogen bonds that connect magnetically inequivalent Co(II) ions (|JAB(1/2)| = 0.055(2) cm(–1)) and the exchange coupling constant associated with a fumarate bridge connecting equivalent Co(II) ions (|JAA(1/2)| ? 0.25 (1) cm(–1)), in good agreement with the average J(3/2) value determined from magnetic measurements. PMID:24528370

Neuman, Nicolás I; Winkler, Elín; Peña, Octavio; Passeggi, Mario C G; Rizzi, Alberto C; Brondino, Carlos D

2014-03-01

35

A one-dimensional reaction coordinate for identification of transition states from explicit solvent P(fold)-like calculations.  

PubMed

A properly identified transition state ensemble (TSE) in a molecular dynamics (MD) simulation can reveal a tremendous amount about how a protein folds and offer a point of comparison to experimentally derived Phi(F) values, which reflect the degree of structure in these transient states. In one such method of TSE identification, dubbed P(fold), MD simulations of individual protein structures taken from an unfolding trajectory are used to directly assess an input structure's probability of folding before unfolding, and P(fold) is, by definition, 0.5 for the TSE. Other, less computationally intensive methods, such as multidimensional scaling (MDS) of the pairwise root mean-squared deviation (RMSD) matrix of the conformations sampled in a thermal unfolding trajectory, have also been used to identify the TSE. Identification of the TSE is made from the original MD simulation without the need to run further simulations. Here we present a P(fold)-like study and describe methods for identification of the TSE through the derivation of a high fidelity, bounded, one-dimensional reaction coordinate for protein folding. These methods are applied to the engrailed homeodomain. The TSE identified by this approach is essentially identical to the TSE identified previously by MDS of the pairwise RMSD matrix. However, the cost of performing P(fold), or even our reduced P(fold)-like calculations, is at least 36,000 times greater than the MDS method. PMID:17978165

Beck, David A C; Daggett, Valerie

2007-11-15

36

Constructing terbium co-ordination polymers of 4,4'-bipyridine-N,N'-dioxide by means of diffusion solvent mixtures.  

PubMed

Five different co-ordination polymers of terbium(III) and the bidentate ligand 4,4'-bipyridine-N,N'-dioxide (L), [Tb(L)(CH(3)OH)(NO(3))(3)](infinity) (1), ([Tb(L)(1.5)(NO(3))(3)].CH(2)Cl(2))(infinity) (2), ([Tb(L)(1.5)(NO(3))(3)].CH(3)OH.0.8H(2)O)(infinity) (3), ([Tb(L)(1.5)(NO(3))(3)].0.4C(2)Cl(4).0.8CH(3)OH)(infinity) (4), and [Tb(L)(2)(NO(3))(3)](infinity) (5) have been synthesised by the use of different "diffusion solvent mixtures", and structurally characterised by X-ray crystallography. Compound 1, with a Tb:L stoichiometry of 1:1, adopts a zig-zag chain structure, which forms three-fold interpenetrating diamondoid frameworks through interchain hydrogen bonding between co-ordinated methanol and a nitrate group on an adjacent chain. Polymers 2, 3, and 4 all have a Tb:L stoichiometry of 1:1.5, but adopt different topologies. For 2, a ladder arrangement is found and large channels which accommodate solvent CH(2)Cl(2) molecules are formed by superposition of the ladders. For 3 and 4 4.8(2) net structures are observed. The superposition of the 4.8(2) nets in 3 and 4, by disposing adjacent layers such that every octagon is positioned below a tetragon from the neighbouring layer, allows the formation of two kinds of channel, with that inside the tetragons accommodating methanol molecules. The other kind of channel, between tetragons, accommodates water molecules in the case of 3 and tetrachloroethylene molecules in the case of 4. Compound 5, with a Tb:L stoichiometry of 1:2, has a linear polymeric structure with one bridging and one terminal ligand, and forms (6,3) plane nets by means of intermolecular electrostatic interactions between N-oxide moieties. X-ray powder diffraction studies show that upon desolvation, compound 2 maintains its original ladder framework. PMID:11981887

Long, De-Liang; Blake, Alexander J; Champness, Neil R; Wilson, Claire; Schröder, Martin

2002-05-01

37

Solvent or temperature induced diverse coordination polymers of silver(I) sulfate and bipyrazole systems: syntheses, crystal structures, luminescence, and sorption properties.  

PubMed

Three new coordination polymers, [Ag4(H2bpz)4(SO4)2]·H2O (1), [Ag2(H2bpz)2(SO4)]·3H2O (2), and [Ag3(H2bpz)4](SO4)2/3(OH)5/3·4H2O (3) have been solvothermally synthesized with Ag2SO4 and flexible ligand 3,3',5,5'-tetramethyl-4,4'-bipyrazole (H2bpz) in different solvents and temperatures. Complex 1 is a 2-fold interpenetrated three-dimensional (3D) framework with an uncommon (3,5)-connected hms topology. Complex 2 is a structural isomer of 1 and shows a three-connected 2D ths net consisting of interesting 3-fold and 2-fold heterochiral helical chains. Complex 3 discloses a grid layer structure, containing heterochiral helical chains and an unusual meso-helix. More interestingly, three sets of layers in 3 stack in different directions, affording an unprecedented 2D + 2D + 2D ? 3D polycatenating cationic framework with 1D + 3D porous systems. In 1-3, H2bpz exhibit exobidentate bridging fashions with wide-ranged interpyrazole tilting angles and changeable coordination configurations, such as cis and trans fashions in 1 and 3 and uniform trans fashion in 2. These lead to the isomeric [Ag(H2bpz)]n arrays of wavelike and helical chains in 1 and 2, respectively. Complexes 1-3 display solid-state photoluminescence stemming from the ligand-centered fluorescent emissions of H2bpz. Because of the highly polar framework, 3 shows excellent adsorption selectivity for CO2 over N2. PMID:24295278

Du, Li-Yun; Shi, Wen-Juan; Hou, Lei; Wang, Yao-Yu; Shi, Qi-Zhen; Zhu, Zhonghua

2013-12-16

38

Microscopic solvation of a lithium atom in water-ammonia mixed clusters: Solvent coordination and electron localization in presence of a counterion  

SciTech Connect

The microsolvation structures and energetics of water-ammonia mixed clusters containing a lithium atom, i.e., Li(H{sub 2}O){sub n}(NH{sub 3}), n=1-5, are investigated by means of ab initio theoretical calculations. Several structural aspects such as the solvent coordination to the metal ion and binding motifs of the free valence electron of the metal are investigated. We also study the energetics aspects such as the dependence of vertical ionization energies on the cluster size, and all these structural and energetics aspects are compared to the corresponding results of previously studied anionic water-ammonia clusters without a metal ion. It is found that the Li-O and Li-N interactions play a very important role in stabilizing the lithium-water-ammonia clusters, and the presence of these metal ion-solvent interactions also affect the characteristics of electron solvation in these clusters. This is seen from the spatial distribution of the singly occupied molecular orbital (SOMO) which holds the ejected valence electron of the Li atom. For very small clusters, SOMO electron density is found to exist mainly at the vicinity of the Li atom, whereas for larger clusters, it is distributed outside the first solvation shell. The free dangling hydrogens of water and ammonia molecules are involved in capturing the SOMO electron density. In some of the conformers, OH(e)HO and OH(e)HN types of interactions are found to be present. The presence of the metal ion at the center of the cluster ensures that the ejected electron is solvated at a surface state only, whereas both surface and interiorlike states were found for the free electron in the corresponding anionic clusters without a metal ion. The vertical ionization energies of the present clusters are found to be higher than the vertical detachment energies of the corresponding anionic clusters which signify a relatively stronger binding of the free electron in the presence of the positive metal counterion. The shifts in different vibrational frequencies are also calculated for the larger clusters, and the results are discussed for some of the selective modes of water and ammonia molecules that are directly influenced by the location and hydrogen bonding state of these molecules in the clusters.

Pratihar, Subha; Chandra, Amalendu [Department of Chemistry, Indian Institute of Technology, Kanpur 208016 (India)

2008-07-14

39

Modulating the structures of copper(I) cyanide coordination polymers by rigid bis(imidazole) ligands and solvents: An experimental and theoretical study  

NASA Astrophysics Data System (ADS)

Four novel copper(I) cyanide coordination polymers, namely, Cu2(CN)2(L1) (1), Cu2(CN)2(L2) (2), Cu2(CN)2(L3) (3) and Cu2(CN)2(L3) (4), have been prepared via the reaction of Cu2+, [Fe(CN)6]4- and three structurally related rigid bis(imidazole) ligands 1,4-bis(1-imidazolyl)benzene (L1), 4,4'-bis(1-imidazolyl)biphenyl (L2) and 5-methyl-1,3-bis(1-imidazolyl)benzene(L3) under solvothermal conditions. Although all complexes contain 1D copper(I) cyanide chains, they have completely different structures of 21 helical chain, zigzag chain, and meso-helical chain for complexes 1, 2, and 3, respectively. Complex 1 presents a distorted 2D (6, 3) layer, and further forms a 3D supramolecular structure by ?⋯? interactions. Complex 2 shows a 3D network with (10, 3)-b topology and exhibits an interesting 3-fold interpenetration structures attributed Class Ia type. Most interestingly, complexes 3 and 4 are a pair of polymorphs, which are yielded simply depending upon the reaction solvent, and also generate a 3D network with (10, 3)-b topology, which display an interesting 4-fold interpenetration, and belong to unusual Class IIIa type. Meanwhile, the nature of metal-ligand bonds in all complexes was further confirmed by density functional theoretical calculations. It was found that the metal-ligand bonds are basically intermediate and covalent dominant interactions in all complexes. An extended analysis of the experimental and theoretical results indicates that the organic ligands play a crucial role in the self-assembly of the final product structures. Moreover, the thermal properties of complexes 1-3 have also been investigated.

Huang, Rong-Yi; Xu, Heng; Ye, Shi-Yong; Wu, Gen-Hua; Zhao, Xiu-Qin; Wang, Yan; Liu, Guang-Xiang

2013-03-01

40

Electrochemistry of cis-diaquo ruthenium(II) complexes with substituted 2,2?-bipyridine ligands in a non-coordinating solvent. Application to the elaboration of corresponding functionalized polypyrrole films  

Microsoft Academic Search

New cis-diaquo ruthenium(II) complexes [Ru(L)2(OH2)2]2+ with L = 2,2?-bipyridine substituted by ramified or long chain alkyl groups have been prepared in order to study their electrochemical behaviour in a non-coordinating solvent like CH2Cl2. Slow mono and bis-aquo substitutions by counter anions (Y?) from the electrolyte are observed leading to [Ru(L)2(OH2)(Y)]+ and [Ru(L)2(Y)2]. The kinetic of the process is time dependent

Marie-Noëlle Collomb-Dunand-Sauthier; Alain Deronzier; Hubert Le Bozec; Marcelo Navarro

1996-01-01

41

Solvent recovery  

Microsoft Academic Search

A brief overview is presented of the economic significance of solvent recovery in the oilseed extraction industry in view\\u000a of the steep price advance of hexane since 1974. The present solvent recovery practices in oilseed plants are outlined with\\u000a addition of operating techniques since 1976. Also, industry trends are noted in terms of improved equipment. Information is\\u000a presented on the

N. W. Myers

1983-01-01

42

Synthesis of room-temperature ionic liquids with the weakly coordinating [Al(ORF)4]- anion (RF=C(H)(CF3)2) and the determination of their principal physical properties.  

PubMed

A large series of ionic liquids (ILs) based on the weakly coordinating alkoxyaluminate [Al(hfip)(4)](-) (hfip: hexafluoroisopropoxy) with classical as well as functionalized cations were prepared, and their principal physical properties determined. Melting points are between 0 ([C(4)MMIM][Al(hfip)(4)]) and 69 °C ([C(3)MPip][Al(hfip)(4)]); three qualify as room-temperature ILs (RTILs). Crystal structures for six ILs were determined; their structural parameters and anion-cation contacts are compared here with known ILs, with a special focus on their influence on physical properties. Moreover, the biodegradability of the compounds was investigated by using the closed-bottle and the manometric respirometry test. Temperature-dependent viscosities and conductivities were measured between 0 and 80 °C, and described by either the Vogel-Fulcher-Tammann (VFT) or the Arrhenius equations. Moreover, conductivities and viscosities were investigated in the context of the molecular volume, V(m). Physical property-V(m) correlations were carried out for various temperatures, and the temperature dependence of the molecular volume was analyzed by using crystal structure data and DFT calculations. The IL ionicity was investigated by Walden plots; according to this analysis, [Al(hfip)(4)](-) ILs may be classified as "very good to good ILs"; while [C(2)MIM][Al(hfip)(4)] is a better IL than [C(2)MIM][NTf(2)]. The dielectric constants of ten [Al(hfip)(4)](-) ILs were determined, and are unexpectedly high (?(r)=11.5 to 16.8). This could be rationalized by considering additional calculated dipole moments of the structures frozen in the solid state by DFT. The determination of hydrogen gas solubility in [Al(hfip)(4)](-) RTILs by high-pressure NMR spectroscopy revealed very high hydrogen solubilities at 25 °C and 1 atm. These results indicate the significant potential of this class of ILs in manifold applications. PMID:20886467

Bulut, Safak; Klose, Petra; Huang, Mian-Mian; Weingärtner, Hermann; Dyson, Paul J; Laurenczy, Gábor; Friedrich, Christian; Menz, Jakob; Kümmerer, Klaus; Krossing, Ingo

2010-11-22

43

Solvent and Temperature Induced Switching Between Structural Isomers of RhI Phosphinoalkyl Thioether (PS) Complexes  

PubMed Central

To develop functional systems based on the weak-link approach (WLA), it is important to understand how solvent and ligand binding strength alter the coordination geometry of complexes formed from this method. A series of phosphinoalkyl thioether (PS) hemilabile ligands with varying electron donating abilities were synthesized and incorporated into homoligated RhI(PS)2Cl complexes to help understand the effects of solvent and ligand binding strength on the preferred coordination modes. The switching between closed and semi-open structural isomers of these RhI(PS)2Cl complexes was studied by variable temperature 31P NMR spectroscopy in different solvent mixtures of CH2Cl2 and THF to obtain thermodynamic parameters (?G°, ?H°, T?S°, and Keq). The isomers differ in the position of the chloride counterion. In the closed isomer, the Cl? anion occupies the outer coordination sphere, while in the semi-open isomer, the Cl? has moved inner sphere and displaced one of the Rh-S bonds. The closed isomer is favored in CH2Cl2 and the semi-open isomer is favored in THF. The preference for either isomer at equilibrium depends on the solvent polarity, based upon the ETN solvent polarity scale, as was determined from 15 different solvents, with more polar solvents favoring the closed isomer. The isomer preference also depends on the electron donating ability of the group attached to the sulfur of the PS ligand, with electron donating groups favoring the closed isomers and electron withdrawing groups favoring the semi-open isomers. The formation of the semi-open isomer from the closed isomer is entropically favored but enthalpically disfavored under all conditions studied. Elucidation of the principles and environments that determine the equilibrium between the two isomers will aid in the design of functional complexes prepared by the WLA.

Wiester, Michael J.; Braunschweig, Adam B.; Mirkin, Chad A.

2010-01-01

44

Weak Deeply Virtual Compton Scattering  

SciTech Connect

We extend the analysis of the deeply virtual Compton scattering process to the weak interaction sector in the generalized Bjorken limit. The virtual Compton scattering amplitudes for the weak neutral and charged currents are calculated at the leading twist within the framework of the nonlocal light-cone expansion via coordinate space QCD string operators. Using a simple model, we estimate cross sections for neutrino scattering off the nucleon, relevant for future high intensity neutrino beam facilities.

Ales Psaker; Wolodymyr Melnitchouk; Anatoly Radyushkin

2007-03-01

45

Polymer thermophoresis in solvents and solvent mixtures  

Microsoft Academic Search

The thermophoresis of homopolymer chains dissolved in a pure non-electrolyte solvent or solvent mixture is theoretically examined. Thermophoresis is related to the temperature-dependent pressure gradient in the solvent layer surrounding the monomer units (mers). The gradient is produced by small changes in the solvent or solvent mixture density due to the mer-solvent interaction. The London-van der Waals interaction was considered

Martin E. Schimpf; Semen N. Semenov

2003-01-01

46

(Electrochemistry in nonaqueous solvents)  

SciTech Connect

The traveler attended the XXVI International Conference on Coordination Chemistry and presented some work entitled An Investigation of the Perchlorate Complexation of Europium(III) in Benzonitrile and Dimethylsulphoxide Using an Ion Exchange Technique.'' Papers of particular interest concerned electrochemistry in nonaqueous solvents (in particular, using electrodes of submicron dimensions that could be applicable to the later actinides); Raman spectroscopy as applied to coordination chemistry, and solution chemistry in nonaqueous solvents with emphasis on identifying the species in solution. The traveler also attended the XIII International Conference on Organometallic Chemistry in Turin, Italy and presented work entitled Synthesis and Characterization of Some Divalent and Trivalent Samarium Organometallic Complexes.'' Papers of particular interest were given in a complete session on organometallic chemistry of the f-elements. Other papers useful to our work concerned d-transition metals where phosphine, arsine, and stibine ligands were used (in order to compare and contrast the behavior with the work we have done on this type of ligand with europium) and phosphide and sulphur bridged type species applicable to both d-transition and f-transition metals.

Payne, G.F.

1988-01-01

47

coordinate plane  

NSDL National Science Digital Library

Become familiar with the coordinate plane. Learn the quadrants and how to graph points and read points on a coordinate plane. You are required to do the assignment and take the quiz. The other resources are to help prepare you for the quiz and book assignment. This is a quick review of the lesson.The Coordinate Plane This is a game to practice plotting and reading points.coordinates game *Assignment: Watch Powerpoint 3.3 and fill in your ...

Olsen

2010-10-07

48

SANS observations on weakly flocculated dispersions  

NASA Astrophysics Data System (ADS)

Structural changes occurring in colloidal dispersions of poly-(methyl metacrylate) (PMMA) particles, sterically stabilized with poly-(12-hydroxystearic acid) (PHSA), while varying the solvent quality, temperature and shear rate, are investigated by small-angle neutron scattering (SANS). For a moderately concentrated dispersion in a marginal solvent the transition on cooling from the effective stability to a weak attraction is monitored. The degree of attraction is determined in the framework of the sticky spheres model (SSM). SANS and rheological results are correlated.

Mischenko, N.; Ourieva, G.; Mortensen, K.; Reynaers, H.; Mewis, J.

1997-02-01

49

Investigating silver coordination to mixed chalcogen ligands.  

PubMed

Six silver(I) coordination complexes have been prepared and structurally characterised. Mixed chalcogen-donor acenaphthene ligands L1-L3 [Acenap(EPh)(E'Ph)] (Acenap = acenaphthene-5,6-diyl; E/E' = S, Se, Te) were independently treated with silver(I) salts (AgBF?/AgOTf). In order to keep the number of variables to a minimum, all reactions were carried out using a 1:1 ratio of Ag/L and run in dichloromethane. The nature of the donor atoms, the coordinating ability of the respective counter-anion and the type of solvent used in recrystallisation, all affect the structural architecture of the final silver(I) complex, generating monomeric, silver(I) complexes {[AgBF?(L)?] (1 L = L1; 2 L = L2; 3 L = L3), [AgOTf(L)?] (4 L = L1; 5 L = L3), [AgBF?(L)?] (2a L = L1; 3a L = L3)} and a 1D polymeric chain {[AgOTf(L3)](n) 6}. The organic acenaphthene ligands L1-L3 adopt a number of ligation modes (bis-monodentate ??-?²-bridging, quasi-chelating combining monodentate and ??-E(phenyl)-Ag(I) and classical monodentate coordination) with the central silver atom at the centre of a tetrahedral or trigonal planar coordination geometry in each case. The importance of weak interactions in the formation of metal-organic structures is also highlighted by the number of short non-covalent contacts present within each complex. PMID:23138535

Knight, Fergus R; Randall, Rebecca A M; Wakefield, Lucy; Slawin, Alexandra M Z; Woollins, J Derek

2012-01-01

50

Study of solute–solvent and solvent–solvent interactions in pure and mixed binary solvents  

Microsoft Academic Search

Solute–solvent and solvent–solvent interactions have been studied in fifteen pure solvents and seven binary aqueous mixtures by monitoring the solubility of a dye in the solvents. The standard Gibbs energy of solvation, as given by log s, where s is the solubility has been found to depend on various modes of solute–solvent interaction and also on the Hildebrand solubility parameter

Angshuman Maitra; Sanjib Bagchi

2008-01-01

51

Preparation of coal slurry with organic solvents.  

PubMed

In this study, various organic solvents were used to prepare coal slurries and the rheological and thermal properties of coal-organic solvent slurries were examined. Solvents with molecules containing unpaired electrons (high basicity) show high extraction power and cause swelling of coal. Therefore, coal-organic solvent slurries usually showed higher viscosities compared to coal-water slurry. In addition, coal slurries prepared by alcohols and cyclohexanone demonstrated lower settling rates but a high specific sedimentation volume presumably because these solvents swelled coal particles well and led to the formation of weak gel structures in the bulk. In addition, ethanol and cyclohexanone are capable of breaking a considerable amount of hydrogen bonds in coal and subsequently opening up the structures. Thus, more surface area is available for combustion and the combustion rate of coal slurries was increased. PMID:17276487

Shin, Yu-Jen; Shen, Yun-Hwei

2007-06-01

52

Gravitational anomaly and Hawking radiation near a weakly isolated horizon  

Microsoft Academic Search

Based on the idea of the work by Wilczek and his collaborators, we consider the gravitational anomaly near a weakly isolated horizon. We find that there exists a universal choice of tortoise coordinate for any weakly isolated horizon. Under this coordinate, the leading behavior of a quite arbitrary scalar field near a horizon is a 2-dimensional chiral scalar field. This

Wu Xiaoning; Huang Chaoguang; Sun Jiarui

2008-01-01

53

Poisson Coordinates.  

PubMed

Harmonic functions are the critical points of a Dirichlet energy functional, the linear projections of conformal maps. They play an important role in computer graphics, particularly for gradient-domain image processing and shape-preserving geometric computation. We propose Poisson coordinates, a novel transfinite interpolation scheme based on the Poisson integral formula, as a rapid way to estimate a harmonic function on a certain domain with desired boundary values. Poisson coordinates are an extension of the Mean Value coordinates (MVCs) which inherit their linear precision, smoothness, and kernel positivity. We give explicit formulae for Poisson coordinates in both continuous and 2D discrete forms. Superior to MVCs, Poisson coordinates are proved to be pseudo-harmonic (i.e., they reproduce harmonic functions on n-dimensional balls). Our experimental results show that Poisson coordinates have lower Dirichlet energies than MVCs on a number of typical 2D domains (particularly convex domains). As well as presenting a formula, our approach provides useful insights for further studies on coordinates-based interpolation and fast estimation of harmonic functions. PMID:22508904

Li, Xian-Ying; Hu, Shi-Min

2012-04-10

54

Astronomical Coordinates  

NSDL National Science Digital Library

The celestial coordinate system is a projection of earth's coordinate system into the celestial sphere. Being just like Earth's system it contains an "equator", lines of "latitude" and "longitude", and even poles. (Though we don't use the same words for it.) One suggestion one might have would be to just extend the Earth's latitude, longitude, and equator out into the night sky, but the Earth is constantly spinning. For the Celestial coordinates, we have to pick some fixed reference to go by.

Joiner, David; The Shodor Education Foundation, Inc.

55

Degreaser Reduces Solvent Loss  

NASA Technical Reports Server (NTRS)

Escape of solvent minimized by second cooling coil. Degreaser suppresses solvent-vapor loss through parts-basket dragout and air drafts. Within C02 blanket, convection repeatedly exposes C02/solvent mixture to cold spot created by C02 coil. Solvent vapor condenses, then runs down via through to cold tank. This small expenditure of C02 minimizes health and environmental hazards.

Du Fresne, E. R.

1985-01-01

56

Solvent wash solution  

DOEpatents

Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Neace, James C. (Blackville, SC) [Blackville, SC

1986-01-01

57

Solvent wash solution  

DOEpatents

A process is claimed for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 vol % of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Neace, J.C.

1984-03-13

58

Geoboard - Coordinate  

NSDL National Science Digital Library

This interactive Java applet lets users explore the coordinate plane through the use of a Geoboard. The user places bands on the board where each peg is at an integer coordinate. Once a band has been placed, the applet outputs the perimeter and area of the shape or, if bands are placed as line segments, the applet outputs the distance and slope of the segment.

1999-01-01

59

Coordinated Checkpointing Without Direct Coordination.  

National Technical Information Service (NTIS)

Coordinated checkpointing is a well known method to achieve fault tolerance in distributed systems. Long running parallel applications and high availability applications are two potential users of checkpointing, although with different requirements. Paral...

N. Neves W. K. Fuchs

1998-01-01

60

Weakly ??-continuous functions  

NASA Astrophysics Data System (ADS)

In this paper we introduce a new class of generalizations of continuous functions via ??-open sets called weakly ??-continuous functions. Moreover, we study some of its fundamental properties and characterizations. The concept of weak ??-continuous is weaker than ??-continuous, weakly ?-continuous and weakly ?-continuous functions, are also discussed.

Aljarrah, Heyam Hussein; Md Noorani, Mohd Salmi

2013-09-01

61

Miscellaneous hydrocarbon solvents.  

PubMed

The solvents discussed in this article are common solvents not categorized as halogenated, aromatic, or botanical. The solvents discussed are categorized into two groups: hydrocarbon mixtures and single agents. The hydrocarbon mixtures discussed are Stoddard solvent, naphtha, and kerosene. The remaining solvents described are n-hexane, methyl n-butyl ketone, dimethylformamide, dimethyl sulfoxide, and butyl mercaptans. Effects common to this group of agents and their unique effects are characterized. Treatment of exposures and toxic effects of these solvents is described, and physiochemical properties and occupational exposure levels are listed. PMID:15325316

Bebarta, Vikhyat; DeWitt, Christopher

2004-08-01

62

Interaction of photosynthetic pigments with various organic solvents  

Microsoft Academic Search

Magnetic circular dichroism (MCD) and absorption spectra have been measured on three intact photosynthetic pigments with the chlorin ring as macrocycle: chlorophyll a, bacteriochlorophyll c and d, in various hydrophilic organic solvents. The MCD intensity of a Qy(0-0) transition for the Mg chlorin derivative was sensitive to the coordination state of the central Mg atom by the solvent molecules. The

Mitsuo Umetsu; Zheng-Yu Wang; Masayuki Kobayashi; Tsunenori Nozawa

1999-01-01

63

Luminescent mechanochromic porous coordination polymers.  

PubMed

Three 2D luminescent isomeric porous coordination polymers are synthesized and characterized. Their luminescence properties can be modified by grinding and they can act as mechanochromic materials and their properties are probably related to the weak interactions of cuprophilicity and ?-? interactions. PMID:24415360

Wen, Tian; Zhou, Xiao-Ping; Zhang, De-Xiang; Li, Dan

2014-01-13

64

Peat dewatering: solvent extraction  

SciTech Connect

The objective of this program is to determine the preliminary technical and economic feasibility of using IGT's solvent-extraction process for the dewatering of peat. Parallel objectives of the program are to: identify organic solvents that can be readily used to dewater raw peat by IGT's solvent-extraction process; design, construct, and operate bench-scale equipment for testing the most promising solvents; and estimate the preliminary economics of the process for a commerical-scale peat dewatering plant using a selective solvent. The results indicate that: solvent-extraction dewatering can remove up to 90% of the water in peat; and diethyl ketone (DEK) and benzene appear to dewater peat better than the other solvents tested. A preliminary economic evaluation of solvent-extraction dewatering of peat with DEK shows that the cost of this type of dewatering method is not currently competitive with other peat dewatering methods. (DWC)

Paganessi, J.E.; Mensinger, M.C.; Tsaros, C.L.; Arora, J.

1981-01-01

65

Solvents safety handbook  

SciTech Connect

Know solvents and how to protect yourself from dangerous exposure to them. Instant information for decision-making regarding industrial solvents in everyday use, is provided in this handbook which is a compilation of data on 335 hazardous and frequently-used solvents.

De Renzo, D.J.

1986-01-01

66

Coordinate Plane  

NSDL National Science Digital Library

5th Grade Math State core Standard 3, Objective 2a: Locate points defined by ordered pairs of integers. Congratulations for earning a game day in the computer lab! Remember that even though it is game day I expect you to stay on task and follow directions. We have been talking in math about graphing integers on the coordinate plane. The games for today require that ...

Zilles, Miss

2007-10-31

67

Weak Value Theory  

SciTech Connect

I show that the weak value theory is useful from the viewpoints of the experimentally verifiability, consistency, capacity for explanation as to many quantum paradoxes, and practical advantages. As an example, the initial state in the Hardy paradox can be experimentally verified using the weak value via the weak measurement.

Shikano, Yutaka [Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan) and Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

2011-03-28

68

Nonclassicality in weak measurements  

SciTech Connect

We examine weak measurements of arbitrary observables where the object is prepared in a mixed state and on which measurements with imperfect detectors are made. The weak value of an observable can be expressed as a conditional expectation value over an infinite class of different generalized Kirkwood quasiprobability distributions. 'Strange' weak values for which the real part exceeds the eigenvalue spectrum of the observable can only be found if the Terletsky-Margenau-Hill distribution is negative or, equivalently, if the real part of the weak value of the density operator is negative. We find that a classical model of a weak measurement exists whenever the Terletsky-Margenau-Hill representation of the observable equals the classical representation of the observable and the Terletsky-Margenau-Hill distribution is non-negative. Strange weak values alone are not sufficient to obtain a contradiction with classical models. We propose feasible weak measurements of photon number of the radiation field. Negative weak values of energy contradict all classical stochastic models, whereas negative weak values of photon number contradict all classical stochastic models where the energy is bounded from below by the zero-point energy. We examine coherent states in particular and find negative weak values with probabilities of 16% for kinetic energy (or squared field quadrature), 8% for harmonic oscillator energy, and 50% for photon number. These experiments are robust against detector inefficiency and thermal noise.

Johansen, Lars M. [Department of Technology, Buskerud University College, N-3601 Kongsberg (Norway); Luis, Alfredo [Departamento de Optica, Facultad de Ciencias Fisicas, Universidad Complutense, 28040 Madrid (Spain)

2004-11-01

69

Would Global Patent Protection be too Weak without International Coordination?  

Microsoft Academic Search

This paper analyzes the setting of national patent policies in the global economy. In the standard model with free trade and social-welfare-maximizing governments à la Grossman and Lai (2004), cross-border positive policy externalities induce individual countries to select patent strengths that are weaker than is optimal from a global perspective. The paper introduces three new features to the analysis: trade

Edwin L.-C. Lai; Isabel K.-M. Yan

2011-01-01

70

Molecular tectonics: anion control of dimensionality and connectivity in meta-pyridyl appended tetramercaptotetrathiacalix[4]arene based silver coordination networks.  

PubMed

The combination of the same organic tecton 1, a meta-pyridyl appended tetramercaptotetrathiacalix[4]arene in 1,3-alternate conformation offering four pyridyl units and eight thioether groups, with three silver salts AgX (X = BF4(-), NO3(-) and SbF6(-)) leads, under identical conditions (concentration, temperature and solvent system), to the formation of different silver coordination networks. Both the connectivity and the dimensionality of the three silver coordination networks depend on the nature of the anion used as a counter ion. Whereas the weakly coordinating BF4(-) anion does not participate in the formation of the non-tubular 1D coordination network, the coordinating NO3(-) anion is bound to the metal cation and this leads to the formation of a tubular 1D silver coordination network. In both cases, the eight S atoms of the tecton 1 do not take part in the binding of the cation. In marked contrast, when the SbF6(-) anion is used as a counter ion, the organic tecton 1 behaves as a tetrakismonodentate through its four meta-pyridyl moieties and as a bischelating unit of the SCCS type leading thus to the formation of a porous 3D diamondoid-type network. PMID:24132039

Ovsyannikov, A; Ferlay, S; Solovieva, S E; Antipin, I S; Konovalov, A I; Kyritsakas, N; Hosseini, M W

2014-01-01

71

Encephalomyeloradiculoneuropathy following exposure to an industrial solvent  

Microsoft Academic Search

A 19-year-old male developed complaints including weakness of the lower extremities and right hand, numbness, dysphagia and urinary difficulties following a 2 month exposure to an industrial solvent constituted mainly of 1-bromopropane, but also containing butylene oxide, 1,3 dioxolane, nitromethane, and other components. Nerve conduction studies revealed evidence of a primary, symmetric demyelinating polyneuropathy. Evidence of CNS involvement came from

Gary Sclar

1999-01-01

72

Alternative Green Solvents Project  

NASA Technical Reports Server (NTRS)

Necessary for safe and proper functioning of equipment. Mainly halogenated solvents. Tetrachloride, Trichloroethylene (TCE), CFC-113. No longer used due to regulatory/safety concerns. Precision Cleaning at KSC: Small % of total parts. Used for liquid oxygen (LOX) systems. Dual solvent process. Vertrel MCA (decafluoropentane (DFP) and trons-dichloroethylene) HFE-7100. DFP has long term environmental concerns. Project Goals: a) Identify potential replacements. b) 22 wet chemical processes. c) 3 alternative processes. d) Develop test procedures. e) Contamination and cleaning. f) Analysis. g) Use results to recommend alternative processes. Conclusions: a) No alternative matched Vertrel in this study. b) No clear second place solvent. c) Hydrocarbons- easy; Fluorinated greases- difficult. d) Fluorinated component may be needed in replacement solvent. e) Process may need to make up for shortcoming of the solvent. f) Plasma and SCC02 warrant further testing.

Maloney, Phillip R.

2012-01-01

73

Weak Probabilistic Anonymity  

Microsoft Academic Search

Anonymity means that the identity of the user performing a certain action is main- tained secret. The protocols for ensuring anonymity often use random mechanisms which can be described probabilistically. In this paper we propose a notion of weak probabilistic anonymity, where weak refers to the fact that some amount of proba- bilistic information may be revealed by the protocol.

Yuxin Deng; Catuscia Palamidessi; Jun Pang

2007-01-01

74

Time resolved solvent rearrangement dynamics.  

PubMed

Ultrafast pump-probe studies of I2- recombination in size-selected I2- (CO2)n cluster ions demonstrate long time coherent motions in size-selected clusters and the resulting non-statistical energy flow in the cluster. For I2- photodissociated to produce either I- + I or I- + I*, we identify a solvent-driven energy transfer process without a condensed phase counterpart. The mechanism involved is a Marcus-like solvent-driven curve crossing, with the driving force arising from asymmetric solvation, not just from solvent orientation. By substituting another halogen for one I atom, we "break" the I2- symmetry, and thus obtain direct information on the electron transfer process. New experiments on IBr- (CO2)n photodissociation products confirm the behavior suspected in the I2- studies. Time-resolved experiments on IBr- and theoretical modeling of the dynamics provide quantitative information on the multiple curve crossings encountered in the recombination process. In related investigations, femtosecond negative ion-neutral-positive ion charge reversal apparatus is employed to investigate transient neutral species evolving along a reaction coordinate. We report studies of the rearrangement dynamics of Cu(OH2) produced by photodetachment of the corresponding anion. Following a controlled delay period, a second ultrafast tunable laser pulse initiates resonant multiphoton photoionization of the time-evolving Cu...OH2 complex. The time-resolved Cu+ and Cu+(OH2) signals provide information both on the prompt dissociation of the complex and on energy redistribution between internal rotational and radial modes of the evolving complex. Calculations of the time evolution of the anion geometric configuration on the neutral potential energy surface yield deeper insight into the nature of the rearrangement process and the energy flow within the complex. PMID:15471355

Sanford, Todd; Andrews, Django; Rathbone, Jeff; Taylor, Mark; Muntean, Felician; Thompson, Matthew; McCoy, Anne B; Parson, Robert; Lineberger, W Carl

2004-01-01

75

Excited state dynamics of 4-Pyrrolidino pyridine in different solvents  

Microsoft Academic Search

Photophysical properties of 4-Pyrrolidino Pyridine (PP) have been delineated from the absorption, steady state and time-resolved spectroscopy in different solvents. Preferential hydrogen bonding of PP with water and also protonation with acid at intercyclic (pyrrolidino) nitrogen lone pair site could be observed. The intramolecular exciplex as predicted from semi-empirical calculations controls the photophysics in weakly polar and nonpolar solvents. In

Prakriti Ranjan Bangal; Sankar Chakravorti

1998-01-01

76

Structural and kinetic studies of lasalocid A (X537A) and its silver, sodium, and barium salts in nonpolar solvents.  

PubMed Central

The ionophore lasalocid A (X537A) and its metal salts have been investigated by high resolution (270 MHz and 360 MHz) proton nuclear magnetic resonance spectroscopy to obtain structural and kinetic information in nonpolar solution. The proton resonances were assigned from double resonance studies on lasalocid A and on its salts, homologs, isomers, and chemically modified derivatives. Studies of proton and carbon longitudinal relaxation time suggest that lasalocid A exists as a monomer, whereas the sodium and barium salts exist as dimers in nonpolar solvents. A study of the magnitude of the vicinal proton coupling constants and the chemical shifts and linewidths of the hydroxyl resonances suggest that the backbone conformation and intramolecular hydrogen bonds are similar for lasalocid A and its sodium and barium salts in nonpolar solvents. Nuclear magnetic resonance studies on the role of bound solvent molecules suggest a tightly bound water molecule in the barium complex dimer (crystallized from water-ethanol) and a weakly bound ethanol molecule in the lasalocid A monomer (crystallized from ethanol) in cyclohexane. The selective changes in proton chemical shift on complexation [where the polar faces of two lasalocid anions coordinate the metal cation(s) in nonpolar solvents have been analyzed in terms of the proximity of the resonances to the cation, their linkage to the coordinating oxygen atoms, and the magnetic anisotropy effects of the polar groups of one ligand on the resonances of its partner in the dimer. The nuclear magnetic resonance studies in solution are compared with earlier observations on lasalocid A and its salts in the crystalline state. Thus, the short Ag-C5 distance in the crystal structure of silver complex dimer is also observed in the solution structure. The kinetic parameters associated with the exchange between lasalocid A and its barium complex in chloroform have been measured from an analysis of the resonance line shapes as a function of temperature. Images

Patel, D J; Shen, C

1976-01-01

77

Weak Bump Quasars.  

National Technical Information Service (NTIS)

Research into the optical, ultraviolet and infrared continuum emission from quasars and their host galaxies was carried out. The main results were the discovery of quasars with unusually weak infrared emission and the construction of a quantitative estima...

B. J. Wilkes J. Mcdowell

1994-01-01

78

Weak localization in graphene  

NASA Astrophysics Data System (ADS)

We review the recently-developed theory of weak localization in monolayer and bilayer graphene. For high-density monolayer graphene and for any-density bilayers, the dominant factor affecting weak localization properties is trigonal warping of graphene bands, which reflects asymmetry of the carrier dispersion with respect to the center of the corresponding valley. The suppression of weak localization by trigonal warping is accompanied by a similar effect caused by random-bond disorder (due to bending of a graphene sheet) and by dislocation/antidislocation pairs. As a result, weak localization in graphene can be observed only in samples with sufficiently strong intervalley scattering, which is reflected by a characteristic form of negative magnetoresistance in graphene-based structures.

Fal'ko, Vladimir I.; Kechedzhi, K.; McCann, E.; Altshuler, B. L.; Suzuura, H.; Ando, T.

2007-07-01

79

SOLVENT WASTE REDUCTION ALTERNATIVES  

EPA Science Inventory

This publication contains edited versions of presentations on this subject made at five Technology Transfer seminars in 1988. Chapters are included on land disposal regulations and requirements; waste solvent disposal alternatives from various industries such as process equipment...

80

Continuous countercurrent membrane column for the separation of solute/solvent and solvent/solvent systems  

DOEpatents

A reverse osmosis membrane process or hybrid membrane - complementary separator process for producing enriched product or waste streams from concentrated and dilute feed streams for both solvent/solvent and solute/solvent systems is described.

Nerad, Bruce A. (Longmont, CO); Krantz, William B. (Boulder, CO)

1988-01-01

81

Continuous countercurrent membrane column for the separation of solute\\/solvent and solvent\\/solvent systems  

Microsoft Academic Search

A reverse osmosis membrane process or hybrid membrane - complementary separator process for producing enriched product or waste streams from concentrated and dilute feed streams for both solvent\\/solvent and solute\\/solvent systems is described.

Bruce A. Nerad; William B. Krantz

1988-01-01

82

Dendritic brushes under theta and poor solvent conditions  

NASA Astrophysics Data System (ADS)

The effects of solvent quality on the internal stratification of polymer brushes formed by dendron polymers up to third generation were studied by means of molecular dynamics simulations with Langevin thermostat. The distributions of polymer units, of the free ends, the radii of gyration, and the back folding probabilities of the dendritic spacers were studied at the macroscopic states of theta and poor solvent. For high grafting densities we observed a small decrease in the height of the brush as the solvent quality decreases. The internal stratification in theta solvent was similar to the one we found in good solvent, with two and in some cases three kinds of populations containing short dendrons with weakly extended spacers, intermediate-height dendrons, and tall dendrons with highly stretched spacers. The differences increase as the grafting density decreases and single dendron populations were evident in theta and poor solvent. In poor solvent at low grafting densities, solvent micelles, polymeric pinned lamellae, spherical and single chain collapsed micelles were observed. The scaling dependence of the height of the dendritic brush at high density brushes for both solvents was found to be in agreement with existing analytical results.

Gergidis, Leonidas N.; Kalogirou, Andreas; Charalambopoulos, Antonios; Vlahos, Costas

2013-07-01

83

Cleaning without chlorinated solvents  

SciTech Connect

Because of health and environmental concerns, many regulations have been passed in recent years regarding the use of chlorinated solvents. The Oak Ridge Y-12 Plant has had an active program to find alternatives for these solvents used in cleaning applications for the past 7 years. During this time frame, the quantity of solvents purchased has been reduced by 92%. The program has been a twofold effort. Vapor degreasers used in batch cleaning-operations have been replaced by ultrasonic cleaning with aqueous detergent, and other organic solvents have been identified for use in hand-wiping or specialty operations. In order to qualify these alternatives for use, experimentation was conducted on cleaning ability as well as effects on subsequent operations such as welding, painting and bonding. Cleaning ability was determined using techniques such as X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) which are capable of examining monolayer levels of contamination on a surface. Solvents have been identified for removal of rust preventative oils, lapping oils, machining coolants, lubricants, greases, and mold releases. Solvents have also been evaluated for cleaning urethane foam spray guns, swelling of urethanes and swelling of epoxies.

Thompson, L.M.; Simandl, R.F.

1994-12-31

84

Weak bond screening system  

NASA Astrophysics Data System (ADS)

Consideration is given to the development of a weak bond screening system which is based on the utilization of a high power ultrasonic (HPU) technique. The instrumentation of the prototype bond strength screening system is described, and the adhesively bonded specimens used in the system developmental effort are detailed. Test results obtained from these specimens are presented in terms of bond strength and level of high power ultrasound irradiation. The following observations were made: (1) for Al/Al specimens, 2.6 sec of HPU irradiation will screen weak bond conditions due to improper preparation of bonding surfaces; (2) for composite/composite specimens, 2.0 sec of HPU irradiation will disrupt weak bonds due to under-cured conditions; (3) for Al honeycomb core with composite skin structure, 3.5 sec of HPU irradiation will disrupt weak bonds due to bad adhesive or oils contamination of bonding surfaces; and (4) for Nomex honeycomb with Al skin structure, 1.3 sec of HPU irradiation will disrupt weak bonds due to bad adhesive.

Chuang, S. Y.; Chang, F. H.; Bell, J. R.

85

Solvent interactions of halophilic malate dehydrogenase.  

PubMed

Malate dehydrogenase from the extreme halophilic Haloarcula marismortui (Hm MalDH) is an acidic protein that is unstable below molar salt concentrations. The solvated folded protein was studied by small-angle neutron scattering in solvents containing salt: NaCl, NaCH(3)CO(2), KF, NH(4)Cl, NH(4)CH(3)CO(2), (NH(4))(2)SO(4), MgCl(2), and MgSO(4). It was found that the global solvent interactions depend mainly on the nature of the cation. Complementary mass density measurements in MgCl(2), NaCl, NaCH(3)CO(2), and (NH(4))(2)SO(4) allowed determining the partial molal volumes of the protein, which were found to increase slightly with the salt, and the preferential salt binding parameters for each solvent condition. These are strongly dependent on the cation type and salt concentration. Hm MalDH can be modeled as an invariant particle binding 4100 water molecules in MgCl(2) and 2000 +/- 200 in NaCl, NaCH(3)CO(2), or (NH(4))(2)SO(4). The number of salt molecules associated to the particle decreases from about 85 to 0 in the order MgCl(2) > NaCl = NaCH(3)CO(2) > (NH(4))(2)SO(4). Alternatively, we considered exchangeable sites for water and salt with the effects of solvent nonideality. It does not change the description of the solvent interactions. Solvent anions act on Hm MalDH stability through a limited number of strong binding sites, as those seen at the interfaces of Hm MalDH by crystallography. Cations would act through some strong and numerous weak binding sites defined on the folded protein, in possible addition to nonspecific hydration effects. PMID:12403625

Ebel, Christine; Costenaro, Lionel; Pascu, Mihaela; Faou, Pierre; Kernel, Blandine; Proust-De Martin, Flavien; Zaccai, Giuseppe

2002-11-01

86

Simple Coordinates Game  

NSDL National Science Digital Library

Investigate the first quadrant of the Cartesian coordinate system through identifying the coordinates of randomly generated points, or requesting that a particular point be plotted. Simple Coordinates Game is one of the Interactivate assessment explorers.

87

Weakly nonadditive Polychronakos statistics  

NASA Astrophysics Data System (ADS)

A two-parameter fractional statistics is proposed, which can be used to model a weakly interacting Bose system. It is shown that the parameters of the introduced weakly nonadditive Polychronakos statistics can be linked to the effects of interactions as well as to finite-size corrections. Calculations are made of the specific heat and condensate fraction of the model system corresponding to harmonically trapped Rb-87 atoms. The behavior of the specific heat of three-dimensional isotropic harmonic oscillators with respect tothe statistics parameters is studied in the temperature domain including the BEC-like phase-transition point.

Rovenchak, Andrij

2014-05-01

88

Solvent immersion imprint lithography.  

PubMed

We present Solvent Immersion Imprint Lithography (SIIL), a technique for polymer functionalization and microsystem prototyping. SIIL is based on polymer immersion in commonly available solvents. This was experimentally and computationally analyzed, uniquely enabling two practical aspects. The first is imprinting and bonding deep features that span the 1 to 100 ?m range, which are unattainable with existing solvent-based methods. The second is a functionalization scheme characterized by a well-controlled, 3D distribution of chemical moieties. SIIL is validated by developing microfluidics with embedded 3D oxygen sensors and microbioreactors for quantitative metabolic studies of a thermophile anaerobe microbial culture. Polystyrene (PS) was employed in the aforementioned applications; however all soluble polymers - including inorganic ones - can be employed with SIIL under no instrumentation requirements and typical processing times of less than two minutes. PMID:24789571

Vasdekis, A E; Wilkins, M J; Grate, J W; Kelly, R T; Konopka, A E; Xantheas, S S; Chang, T-M

2014-06-21

89

Safe battery solvents  

DOEpatents

An ion transporting solvent maintains very low vapor pressure, contains flame retarding elements, and is nontoxic. The solvent in combination with common battery electrolyte salts can be used to replace the current carbonate electrolyte solution, creating a safer battery. It can also be used in combination with polymer gels or solid polymer electrolytes to produce polymer batteries with enhanced conductivity characteristics. The solvents may comprise a class of cyclic and acyclic low molecular weight phosphazenes compounds, comprising repeating phosphorus and nitrogen units forming a core backbone and ion-carrying pendent groups bound to the phosphorus. In preferred embodiments, the cyclic phosphazene comprises at least 3 phosphorus and nitrogen units, and the pendent groups are polyethers, polythioethers, polyether/polythioethers or any combination thereof, and/or other groups preferably comprising other atoms from Group 6B of the periodic table of elements.

Harrup, Mason K. (Idaho Falls, ID); Delmastro, Joseph R. (Idaho Falls, ID); Stewart, Frederick F. (Idaho Falls, ID); Luther, Thomas A. (Idaho Falls, ID)

2007-10-23

90

Halogenated solvent remediation  

DOEpatents

Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. An illustrative method includes adding an electron donor for microbe-mediated anaerobic reductive dehalogenation of the halogenated solvents, which electron donor enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative electron donors include C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof, of which lactic acid, salts of lactic acid--such as sodium lactate, lactate esters, and mixtures thereof are particularly illustrative. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the electron donor.

Sorenson, Jr., Kent S. (Windsor, CO)

2008-11-11

91

Solvent resistant copolyimide  

NASA Technical Reports Server (NTRS)

A solvent resistant copolyimide was prepared by reacting 4,4'-oxydiphthalic anhydride with a diaimine blend comprising, based on the total amount of the diamine blend, about 75 to 90 mole percent of 3,4'-oxydianiline and about 10 to 25 mole percent p-phenylene diamine. The solvent resistant copolyimide had a higher glass transition temperature when cured at 350.degree. , 371.degree. and 400.degree. C. than LaRC.TM.-IA. The composite prepared from the copolyimide had similar mechanical properties to LaRC.TM.-IA. Films prepared from the copolyimide were resistant to immediate breakage when exposed to solvents such as dimethylacetamide and chloroform. The adhesive properties of the copolyimide were maintained even after testing at 23.degree., 150.degree., 177.degree. and 204.degree. C.

Chang, Alice C. (Inventor); St. Clair, Terry L. (Inventor)

1995-01-01

92

A coordination chemistry study of hydrated and solvated cationic vanadium ions in oxidation states +III, +IV, and +V in solution and solid state  

PubMed Central

The coordination chemistry of hydrated and solvated vanadium(III), oxovanadium(IV), and dioxovanadium(V) ions in the oxygen donor solvents water, dimethylsulfoxide (dmso) and N,N?-dimethylpropyleneurea (dmpu) has been studied in solution by EXAFS and large angle X-ray scattering (LAXS) and in solid state by single crystal X-ray diffraction and EXAFS. The hydrated vanadium(III) ion has a regular octahedral configuration with a mean V-O bond distance of 1.99 Å. In the hydrated and dimethylsulfoxide solvated oxovanadium(IV) ions vanadium binds strongly to an oxo group at ca. 1.6 Å. The solvent molecule trans to the oxo group is very weakly bound, at ca. 2.2 Å, while the remaining four solvent molecules, with a mean V-O bond distance of 2.0 Å, form a plane slightly below the vanadium atom; the mean O=V-Operp bond angle is ca. 98°. In the dmpu solvated oxovanadium(IV) ion, the space demanding properties of the dmpu molecule leaving no solvent molecule in the trans position to the oxo group which reduces the coordination number to 5. The O=V-O bond angle is consequently much larger, 106°, and the mean V=O and V-O bond distances decrease to 1.58 and 1.97 Å, respectively. The hydrated and dimethylsulfoxide solvated dioxovanadium(V) ions display a very distorted octahedral configuration with the oxo groups in cis position with mean V=O bond distances of 1.6 Å and a O=V=O bond angle of ca. 105°. The solvent molecules trans to the oxo groups are weakly bound, at ca. 2.2 Å, while the remaining two have bond distances of 2.02 Å. The experimental studies of the coordination chemistry of hydrated and solvated vanadium(III,IV,V) ions are complemented by summarizing previously reported crystal structures to yield a comprehensive description of the coordination chemistry of vanadium with oxygen donor ligands.

Krakowiak, Joanna; Lundberg, Daniel

2012-01-01

93

Quantum weak turbulence  

SciTech Connect

The present manuscript dealing with large occupation of states of a quantum system, extends the study to the case of quantum weak turbulence. The quasiparticle spectrum, calculated for such a system, using a Green's function approach, establishes the dissipative and inertial regimes, hence a Kolmogorov type of picture.

Sanyal, Devashish [Department of Theoretical Physics, Indian Association for the Cultivation of Science, Jadavpur, Calcutta 700032 (India)]. E-mail: tpds@mahendra.iacs.res.in; Sen, Siddhartha [School of Mathematics, Trinity College, Dublin 2 (Ireland)]. E-mail: sen@maths.tcd.ie

2006-06-15

94

Weak decays at PEP  

SciTech Connect

Results are presented on four aspects of weak decays. The MARK II measurement of the tau lifetime, the MARK II measurement of the D/sup 0/ lifetime, the measurement from several experiments of the semi-leptonic branching fractions of hadrons constraining b and c quarks, and lastly the MAC measurement of the B lifetime. 30 references.

Yelton, J.M.

1984-04-01

95

The Weak Mixing Matrix  

NASA Astrophysics Data System (ADS)

We show that the Weak Mixing Matrix, ( *20c Uud & Uus & Uub Ucd & Ucs & Ucb Utd & Uts & Utb ) , is not equal to the product of rotations, and in particular, it is not equal to the KM, or the PDG Matrices. At most, we may find an approximating matrix for the Weak Mixing Matrix that is based on the rotation matrices. We show that one such approximating matrix for the Real part of the Weak Mixing Matrix is ( *20c ?C?C^3 & ?C?C^3 & ^3 ?C?C^2 - ?C?C^2 & ?C?C^2 & ^2 ?C - ?C^3 ?C & - ?C?C^3 ^2 ?C & ?C^2 ?C^3 ), where ?C is the Cabbibo angle. The approximating matrix depends on ?C alone, and predicts the Real part of the Weak Mixing Matrix to a high degree of accuracy. We establish, with a Chi-Squared Goodness-of- Fitness-Test, that our approximating matrix can be used with extremely high level of statistical confidence.

Dannon, Vic; Levine, Robert

2009-10-01

96

N-? weak transition  

NASA Astrophysics Data System (ADS)

A short review of the Rein-Sehgal and isobar models is presented. The attention is focused on the nucleon-?(1232) weak transition form-factors. The results of the recent re-analyses of the ANL and BNL bubble chamber neutrino-deuteron scattering data are discussed.

Graczyk, Krzysztof M.

2011-11-01

97

ENGINEERING BULLETIN: SOLVENT EXTRACTION  

EPA Science Inventory

Solvent extraction does not destroy hazardous contaminants, but is a means of separating those contaminants from soils, sludges, and sediments, thereby reducing the volume of the hazardous material that must be treated. enerally it is used as one in a series of unit operations an...

98

ONSITE SOLVENT RECOVERY  

EPA Science Inventory

This study evaluated the product quality, waste reduction/pollution prevention, and economic aspects of three technologies for onsite solvent recovery. The technologies were (1) atmospheric batch distillation, (2) vacuum heat-pump distillation, and (3) low-emission vapor degreas...

99

Weak Observables in MV Algebras  

Microsoft Academic Search

A notion of a weak observable is defined and aconstruction of a weak observable is examined. With thehelp of the construction, the sum of weak observables isrealized as well as the upper and lower limits of a sequence of weak observables.

Beloslav Riecan

1998-01-01

100

Hysteresis in weak ferromagnets  

NASA Astrophysics Data System (ADS)

Magnetic hysteresis is studied in the orthoferrites ErFeO3 and TmFeO3 using the single crystal samples of millimeter dimensions. It is shown that in both materials one observes a temperature transition manifesting itself through the temperature hysteresis of the magnetic moment and a peculiar temperature evolution of the field hysteresis loop shapes near this transition. Experiments rule out the hypothesis that the ordering of the orthoferrite's rare earth magnetic moments plays an important role in these phenomena. The hysteresis curves can be explained by a few-domain magnetic state of the samples that results from the weak ferromagnetism of the orthoferrites. The phenomenon is generic for weak ferromagnets with temperature dependent magnetization. A large characteristic magnetic length makes the behavior of the relatively big samples analogous to that observed in the nano-size samples of strong ferromagnets.

Bazaliy, Ya. B.; Tsymbal, L. T.; Kakazei, G. N.; Vasiliev, S. V.

2011-03-01

101

Weak Gravitational Lensing  

NASA Astrophysics Data System (ADS)

This chapter reviews the data mining methods recently developed to solve standard data problems in weak gravitational lensing. We detail the different steps of the weak lensing data analysis along with the different techniques dedicated to these applications. An overview of the different techniques currently used will be given along with future prospects. Until about 30 years ago, astronomers thought that the Universe was composed almost entirely of ordinary matter: protons, neutrons, electrons, and atoms. The field of weak lensing has been motivated by the observations made in the last decades showing that visible matter represents only about 4-5% of the Universe (see Figure 14.1). Currently, the majority of the Universe is thought to be dark, that is, does not emit electromagnetic radiation. The Universe is thought to be mostly composed of an invisible, pressure less matter - potentially relic from higher energy theories - called "dark matter" (20-21%) and by an even more mysterious term, described in Einstein equations as a vacuum energy density, called "dark energy" (70%). This "dark" Universe is not well described or even understood; its presence is inferred indirectly from its gravitational effects, both on the motions of astronomical objects and on light propagation. So this point could be the next breakthrough in cosmology. Today's cosmology is based on a cosmological model that contains various parameters that need to be determined precisely, such as the matter density parameter Omega_m or the dark energy density parameter Omega_lambda. Weak gravitational lensing is believed to be the most promising tool to understand the nature of dark matter and to constrain the cosmological parameters used to describe the Universe because it provides a method to directly map the distribution of dark matter (see [1,6,60,63,70]). From this dark matter distribution, the nature of dark matter can be better understood and better constraints can be placed on dark energy, which affects the evolution of structures. Gravitational lensing is the process by which light from distant galaxies is bent by the gravity of intervening mass in the Universe as it travels toward us. This bending causes the images of background galaxies to appear slightly distorted, and can be used to extract important cosmological information. In the beginning of the twentieth century, A. Einstein predicted that massive bodies could be seen as gravitational lenses that bend the path of light rays by creating a local curvature in space time. One of the first confirmations of Einstein's new theory was the observation during the 1919 solar eclipse of the deflection of light from distant stars by the sun. Since then, a wide range of lensing phenomena have been detected. The gravitational deflection of light by mass concentrations along light paths produces magnification, multiplication, and distortion of images. These lensing effects are illustrated by Figure 14.2, which shows one of the strongest lenses observed: Abell 2218, a very massive and distant cluster of galaxies in the constellation Draco. The observed gravitational arcs are actually the magnified and strongly distorted images of galaxies that are about 10 times more distant than the cluster itself. These strong gravitational lensing effects are very impressive but they are very rare. Far more prevalent are weak gravitational lensing effects, which we consider in this chapter, and in which the induced distortion in galaxy images is much weaker. These gravitational lensing effects are now widely used, but the amplitude of the weak lensing signal is so weak that its detection relies on the accuracy of the techniques used to analyze the data. Future weak lensing surveys are already planned in order to cover a large fraction of the sky with high accuracy, such as Euclid [68]. However, improving accuracy also places greater demands on the methods used to extract the available information.

Pires, Sandrine; Starck, Jean-Luc; Leonard, Adrienne; Réfrégier, Alexandre

2012-03-01

102

Composite weak bosons  

SciTech Connect

Dynamical mechanism of composite W and Z is studied in a 1/N field theory model with four-fermion interactions in which global weak SU(2) symmetry is broken explicitly by electromagnetic interaction. Issues involved in such a model are discussed in detail. Deviation from gauge coupling due to compositeness and higher order loop corrections are examined to show that this class of models are consistent not only theoretically but also experimentally.

Suzuki, M.

1988-04-01

103

Ferroelectrically induced weak ferromagnetism.  

SciTech Connect

We present a strategy to design structures for which a polar lattice distortion induces weak ferromagnetism. We identify a large class of multiferroic oxides as potential realizations and use density-functional theory to screen several promising candidates. By elucidating the interplay between the polarization and the Dzyaloshinskii-Moriya vector, we show how the direction of the magnetization can be switched between 180{sup o} symmetry equivalent states with an applied electric field.

Fennie, C. J.; Center for Nanoscale Materials

2008-01-01

104

A coordination framework for supply chain inventory alignment  

Microsoft Academic Search

Purpose – A traditional supply chain, all too often, is a sequence of weakly connected activities both within and outside the organization and leads to many misalignments. Tackling this inherent lack of coordination is a major value creation opportunity for supply chain managers. This paper aims to present a coordination framework, called ASCEND, to align the inventory decisions in decentralized

Rajesh Piplani; Yonghui Fu

2005-01-01

105

PARIS II: DESIGNING GREENER SOLVENTS  

EPA Science Inventory

PARIS II (the program for assisting the replacement of industrial solvents, version II), developed at the USEPA, is a unique software tool that can be used for customizing the design of replacement solvents and for the formulation of new solvents. This program helps users avoid ...

106

Hazardous solvent substitution  

SciTech Connect

Eliminating hazardous solvents is good for the environment, worker safety, and the bottom line. However, even though we are motivated to find replacements, the big question is `What can we use as replacements for hazardous solvents?`You, too, can find replacements for your hazardous solvents. All you have to do is search for them. Search through the vendor literature of hundreds of companies with thousands of products. Ponder the associated material safety data sheets, assuming of course that you can obtain them and, having obtained them, that you can read them. You will want to search the trade magazines and other sources for product reviews. You will want to talk to users about how well the product actually works. You may also want to check US Environmental Protection Agency (EPA) and other government reports for toxicity and other safety information. And, of course, you will want to compare the product`s constituent chemicals with the many hazardous constituency lists to ensure the safe and legal use of the product in your workplace.

Twitchell, K.E.

1995-11-01

107

Effects of solute-solvent and solvent-solvent attractive interactions on solute diffusion  

Microsoft Academic Search

A study is reported on the diffusion process of a solute molecule in a Lennard-Jones-like liquid near the triple point by a molecular dynamics simulation. Systematic changes were made to the strength of the solute-solvent or solvent-solvent attractive interaction in order to elucidate its effects on the diffusion coefficient. When the solute-solvent attractive interaction is enhanced, the diffusion coefficient of

T. Yamaguchi; Y. Kimura

2000-01-01

108

Analysis of Solvent–Solvent Interactions in Mixed Isosteric Solvents by Inverse Gas Chromatography  

Microsoft Academic Search

The Flory–Huggins interaction parameter, ?\\u000a 23, characterizing the interaction between solvents in a mixed stationary phase has been calculated using inverse gas chromatography\\u000a (IGC). The ?\\u000a 23 parameters for four mixed solvent systems formed by mixing a non-polar branched alkane, 19, 24-dioctadecyldotetracontane\\u000a (C78), with four different polar solvents are analysed as a function of temperature. Two of the polar solvents

T. V. M. Sreekanth; K. S. Reddy

2007-01-01

109

SOLVENT FIRE BY-PRODUCTS  

SciTech Connect

Southwest Research Institute (SwRI) conducted a burn test of the Caustic-Side Solvent Extraction (CSSX) solvent to determine the combustion products. The testing showed hydrogen fluoride gas is not a combustion product from a solvent fire when up to 70% of the solvent is consumed. The absence of HF in the combustion gases may reflect concentration of the modifier containing the fluoride groups in the unburned portion. SwRI reported results for other gases (CO, HCN, NOx, formaldehyde, and hydrocarbons). The results, with other supporting information, can be used for evaluating the consequences of a facility fire involving the CSSX solvent inventory.

Walker, D; Samuel Fink, S

2006-05-22

110

Uranyl-oxo coordination directed by non-covalent interactions.  

PubMed

Directed coordination of weakly Lewis acidic K(+) ions to weakly Lewis basic uranyl oxo ligands is accomplished through non-covalent cation-? and cation-F interactions for the first time. Comparison of a family of structurally related diarylamide ligands highlights the role that the cation-? and cation-F interactions play in guiding coordination. Cation binding to uranyl is demonstrated in the solid state and in solution, providing the shortest reported crystallographic uranyl-oxo to potassium distance. UV-Vis, TD-DFT calculations, and electrochemical measurements show that cation coordination directly impacts the electronics at the uranium(vi) cation. PMID:24894554

Lewis, Andrew J; Yin, Haolin; Carroll, Patrick J; Schelter, Eric J

2014-06-24

111

Coordination of Client Services.  

ERIC Educational Resources Information Center

Case coordination is an important social work activity with roots in the earliest objectives and functions of the profession. This article outlines the theoretical framework of case coordination and describes the tasks, skills, and knowledge essential to it. (Author)

Bertsche, Anne Vandeberg; Horejsi, Charles R.

1980-01-01

112

Muscular Dystrophy Coordinating Committee  

MedlinePLUS

The Muscular Dystrophy Community Assistance, Research, and Education Amendments of 2001 ("MD-CARE Act"; P.L. 107-84) authorized the establishment of the Muscular Dystrophy Coordinating Committee (MDCC) to coordinate activities across NIH ...

113

Cook-Coordinate Plane  

NSDL National Science Digital Library

Become familiar with the coordinate plane. Learn the quadrants and how to graph points and read points on a coordinate plane. You are required to do the assignment and take the quiz. The other resources are to help prepare you for the quiz and book assignment. This is a quick review of the lesson.The Coordinate Plane This is a game to practice plotting and reading points.coordinates game *Assignment: Watch Powerpoint 3.3 and fill in your ...

Cook, Miss

2010-10-12

114

Processing Coordination Ambiguity  

ERIC Educational Resources Information Center

We examined temporarily ambiguous coordination structures such as "put the butter in the bowl and the pan on the towel." Minimal Attachment predicts that the ambiguous noun phrase "the pan" will be interpreted as a noun-phrase coordination structure because it is syntactically simpler than clausal coordination. Constraint-based theories assume…

Engelhardt, Paul E.; Ferreira, Fernanda

2010-01-01

115

LCLS Undulator Coordinate System  

SciTech Connect

This note defines the LCLS undulator coordinate system and relates that coordinate system to the linear accelerator coordinate system. The slight downward pitch of the SLAC linac and the finite radius of the Earth necessitate some choices and definitions for the undulator layout which is described here. The layout described is consistent with the LCLS optics MAD file ''LCLS13APR04''.

Bong, E.

2005-01-31

116

Hyperconjugation-mediated solvent effects in phosphoanhydride bonds.  

PubMed

Density functional theory and natural bond orbital analysis are used to explore the impact of solvent on hyperconjugation in methyl triphosphate, a model for "energy rich" phosphoanhydride bonds, such as found in ATP. As expected, dihedral rotation of a hydroxyl group vicinal to the phosphoanhydride bond reveals that the conformational dependence of the anomeric effect involves modulation of the orbital overlap between the donor and acceptor orbitals. However, a conformational independence was observed in the rotation of a solvent hydrogen bond. As one lone pair orbital rotates away from an optimal antiperiplanar orientation, the overall magnitude of the anomeric effect is compensated approximately by the other lone pair as it becomes more antiperiplanar. Furthermore, solvent modulation of the anomeric effect is not restricted to the antiperiplanar lone pair; hydrogen bonds involving gauche lone pairs also affect the anomeric interaction and the strength of the phosphoanhydride bond. Both gauche and anti solvent hydrogen bonds lengthen nonbridging O-P bonds, increasing the distance between donor and acceptor orbitals and decreasing orbital overlap, which leads to a reduction of the anomeric effect. Solvent effects are additive with greater reduction in the anomeric effect upon increasing water coordination. By controlling the coordination environment of substrates in an active site, kinases, phosphatases, and other enzymes important in metabolism and signaling may have the potential to modulate the stability of individual phosphoanhydride bonds through stereoelectronic effects. PMID:23009395

Summerton, Jean C; Evanseck, Jeffrey D; Chapman, Michael S

2012-10-18

117

Weakly bound states of the He-He-Mg trimer  

SciTech Connect

We search for the existence of the weakly bound He-He-Mg molecules. The He-He-Mg molecule is treated as a three-body system. By using hyperspherical coordinates, the Schroedinger equation for the triatomic system is solved in the adiabatic approximation. We obtain that the binding of the three atoms is possible. The binding energies of such molecules are estimated.

Li Yong; Huang Deping [Department of Physics, Huazhong Normal University, Wuhan 430079 (China); Gou Qingdong [Department of Physics, Huazhong Normal University, Wuhan 430079 (China); College of Mathematics and Physics, Jinggangshan University, Ji'an 343009 (China); Han Huili; Shi Tingyun [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China)

2011-07-15

118

Weak values and entanglement concentration  

Microsoft Academic Search

Weak measurements are a special class of indirect measurements where the signal system is both pre and post-selected in particular quantum states. The accompanying probe system records information about the associated weak value of the interaction between the pre and post-selection and is modified by it. We provide a review of the operational application of weak measurement formalism to entanglement

David Menzies; Natalia Korolkova

2009-01-01

119

Weak lensing and dark energy  

Microsoft Academic Search

We study the power of upcoming weak lensing surveys to probe dark energy. Dark energy modifies the distance-redshift relation as well as the matter power spectrum, both of which affect the weak lensing convergence power spectrum. Some dark-energy models predict additional clustering on very large scales, but this probably cannot be detected by weak lensing alone due to cosmic variance.

Dragan Huterer

2002-01-01

120

Weak Acid Equilibrium  

NSDL National Science Digital Library

Students are asked to calculate the pH of a weak acid aqueous solution. The problems involve a series of generic acids with assigned equilibrium constants (Ka) and total concentrations (Ct). Initially, students are required to hand calculate all problems by algebraic manipulation of the mathematical relationships of the system. The solution is a cubic equation. Through a series of assumptions, the solution is simplified. The assumptions are based on the chemistry of the system given the Ka and Ct for the problem. The problems are then graphically solved. Ultimately, the students develop an Excel worksheet to solve the problems and a Bjerrum plot to display the speciation as a function of pH.

Stapleton, Michael

121

Carbon-13 nuclear magnetic resonance spectra of potassium (ethylenediaminetetraacetato)cobaltate(III) in organic solvents  

SciTech Connect

The carbon-13 NMR spectra of the (Co(edta))/sup /minus// (edta = ethylenediaminetetraacetate) anion were observed in water and a variety of organic solvents: ethylene glycol, methanol, formamide, ethanol, 2-propanol, chloroform, dichloromethane, dimethyl sulfoxide, acetonitrile, dimethylformamide, benzonitrile, and dimethylacetamide. The spectra in organic solvents were obtained after 1-2-h accumulations for the concentrated solutions (0.5 M) of the complex anion that were prepared by the addition of a macrobicyclic polyether, cryptand 222, to the solvents. The /sup 13/C NMR signals of the coordinated carboxylates are markedly shifted downfield in protic solvents in comparison with aprotic solvent (the greatest difference in chemical shift is 3.9 ppm), while the NMR chemical shifts of methylene carbons of ligands are not significantly influenced by solvent molecules. The magnitudes (/sigma/ values) of this downfield shift of the coordinated carboxylate /sup 13/C signals are found to be correlated linearly with the electrophilic ability of the solvent molecules. This finding leads to the conclusion that the (Co(edta))/sup /minus// anion interacts with solvent molecules through the hydrogen-bonding between solvent hydrogens and carboxyl oxygens of the complex anion. 10 references, 4 figures, 1 table.

Taura, Toshiaki

1988-08-10

122

Solvent Blending Strategy to Upgrade MCU CSSX Solvent to Equivalent Next-Generation CSSX Solvent  

SciTech Connect

The results of the present study have validated an equal-volume blending strategy for upgrading freshly prepared CSSX solvent to a blended solvent functionally equivalent to NG-CSSX solvent. It is shown that blending fresh CSSX solvent as currently used in MCU with an equal volume of an NG-CSSX solvent concentrate of appropriate composition yields a blended solvent composition (46.5 mM of MaxCalix, 3.5 mM of BOBCalixC6, 0.5 M of Cs-7SB, 3 mM of guanidine suppressor, and 1.5 mM of TOA in Isopar L) that exhibits equivalent batch ESS performance to that of the NG-CSSX solvent containing 50 mM of MaxCalix, 0.5 M of Cs-7SB, and 3 mM of guanidine suppressor in Isopar L. The solvent blend composition is robust to third-phase formation. Results also show that a blend containing up to 60% v/v of CSSX solvent could be accommodated with minimal risk. Extraction and density data for the effect of solvent concentration mimicking diluent evaporation or over-dilution of the equal-volume blended solvent are also given, providing input for setting operational limits. Given that the experiments employed all pristine chemicals, the results do not qualify a blended solvent starting with actual used MCU solvent, which can be expected to have undergone some degree of degradation. Consequently, further work should be considered to evaluate this risk and implement appropriate remediation if needed.

Delmau, Laetitia Helene [ORNL; Moyer, Bruce A [ORNL

2012-12-01

123

Method for extraction solvent recovery  

SciTech Connect

A method for recovery of extraction solvent from a dissolved solute wherein halogen gas evolution and halogen compound retention in the solute are minimized comprises heating a solution of a halogenated organic solvent and the extracted solute in the presence of an ammonium, Group I metal or Group II metal salt of an acid of carbon number 1 to 6, such as ammonium bicarbonate, ammonium carbonate, ammonium formate, sodium carbonate, sodium formate, or calcium formate, to recover the solvent and the solute.

Wolff, W. F.

1985-10-22

124

2,5-PRODAN Derivatives as Highly Sensitive Sensors of Low Solvent Acidity.  

PubMed

Two 5-acyl-2-dimethylaminonaphthalene derivatives, one with a propionyl group and the other with a fused cyclohexanone ring, are investigated as sensors of H-bond-donating ability in protic solvents of low solvent acidity. Their fluorescence is highly quenched in protic solvents, and the quenching order of magnitude is linearly related to the H-bond-donating ability of the solvent as quantified by the solvent acidity (SA) scale. As the solvent acidity increases from 0.15 to 0.40, the fluorescence for both is quenched by more than a factor of ten; thus, they are extremely sensitive sensors of the hydrogen-bond-donating ability in this weakly acidic range. Preferential solvation studies suggest that quenching occurs from a doubly H-bonded excited state. PMID:24853615

Yoon, Alexandra H; Whitworth, Laura C; Wagner, Joel D; Abelt, Christopher J

2014-01-01

125

Coumarin6 interaction with solvents  

NASA Astrophysics Data System (ADS)

Bonding arrangements and changes induced by chemicals in structure/bonding of laser dyes molecule can be investigated from the study of IR spectra. These changes are expected to depend upon the nature of interacting solvent. In the present study, we have studied the FTIR spectra of Coumarin6 in powder form and in different solvents in order to investigate the effect of solvents on Coumarin6 molecule by observing the changes in the spectra. This study may provide the deeper understanding of the sensing properties of Coumarin 6 and also the dependence of its fluorescence and, therefore, lasing property on solvents.

Sharma, Amit

2013-06-01

126

Explicitly computing geodetic coordinates from Cartesian coordinates  

NASA Astrophysics Data System (ADS)

This paper presents a new form of quartic equation based on Lagrange's extremum law and a Groebner basis under the constraint that the geodetic height is the shortest distance between a given point and the reference ellipsoid. A very explicit and concise formulae of the quartic equation by Ferrari's line is found, which avoids the need of a good starting guess for iterative methods. A new explicit algorithm is then proposed to compute geodetic coordinates from Cartesian coordinates. The convergence region of the algorithm is investigated and the corresponding correct solution is given. Lastly, the algorithm is validated with numerical experiments.

Zeng, H.

2013-04-01

127

On the coupling of solvent characteristics to the electronic structure of solute molecules.  

PubMed

We present the results of a theoretical investigation focusing on the solvent structure surrounding the -1, 0 and +1 charged species of F, Cl, Br and I halogen atoms and F2, Cl2, Br2 and I2 di-halogen molecules in a methanol solvent and its influence on the electronic structure of the solute molecules. Our results show a large stabilizing effect arising from the solute-solvent interactions. Well-formed first solvation shells are observed for all species, the structure of which is strongly influenced by the charge of the solute species. Detailed analysis reveals that coordination number, CN, solvent orientation, ?, and solute-solvent distance, d, are important structural characteristics which are coupled to changes in the electronic structure of the solute. We propose that the fundamental chemistry of any solute species is generally regulated by these solvent degrees of freedom. PMID:24435016

Bogatko, Stuart; Cauët, Emilie; Geerlings, Paul; De Proft, Frank

2014-02-28

128

Tax Coordination and Unemployment  

Microsoft Academic Search

This paper analyses the implications of unemployment for fiscal competition and tax coordination among small open economies.\\u000a Unemployment is modeled as resulting from wage bargaining. The analysis focuses on the effect of labour and capital tax coordination\\u000a on welfare. We show that, while coordinated capital and labour tax increases unambiguously raise welfare if labour markets\\u000a are competitive, different results emerge

Clemens Fuest; Bernd Huber

1999-01-01

129

Femtosecond transient dichroism/birefringence studies of solute- solvent friction and solvent dynamics  

SciTech Connect

Ultrafast, heterodyne, polarization spectroscopies are used to measure solute-solvent frictional coupling and characterize the neat solvent`s relaxation dynamics on femtosecond and picosecond timescales.

Chang, Y.J.; Castner, E.W. Jr. [Brookhaven National Lab., Upton, NY (United States); Konitsky, W.; Waldeck, D.H. [Pittsburgh Univ., PA (United States). Dept. of Chemistry

1994-02-01

130

A New Equation between Surface Tensions and Solubility Parameters without Molar Volume Parameters Simultaneously Fitting Polymers and Solvents  

Microsoft Academic Search

Both surface tension and solubility parameter are decided by molecular interactions. There are several empirical equations describing their connection. However, at least two limitations exist for them: polymers cannot be treated and only apolar or weakly polar solvents can be fitted. We found when only the dispersive properties were considered, for 37 solvents and 22 polymers, a linear relationship exists

Lina Jia; Baoli Shi

2011-01-01

131

High Pressure Studies of Solvent Effects on Anthracene Spectra  

PubMed Central

Measurements have been made of the effect of pressure on the peak location and peak shape for anthracene in a variety of liquid and plastic environments; both absorption and fluorescence studies were made. The results are discussed from two standpoints: in terms of the dielectric model and of a configuration coordinate model. For the latter model, the change of configuration coordinate (volume decrease of the system upon electronic excitation) is shown to correlate well with the product of the compressibility and polarizability of the solvent. For the dielectric model, it is found that the change of cavity volume with density is complex. However, the relative cavity volume obtained from emission measurements was consistently 10-15% smaller than that obtained from absorption. The cavity volume decreased with increasing polarizability of the solvent, and results obtained from absorption and emission were quite consistent in this regard.

Okamoto, B. Y.; Drickamer, H. G.

1974-01-01

132

Representation of weakly harmonizable processes  

PubMed Central

Weakly harmonizable processes are represented by a family of positive definite contractive linear operators in a Hilbert space. This generalizes the known result on weakly stationary processes involving a unitary family. A characterization of the vector Fourier integral of a measure on R ? [unk], a reflexive space, is given, and this yields another characterization of weakly harmonizable processes when [unk] is a Hilbert space. Also these processes are shown to have associated spectra, yielding a positive solution to a problem of Rozanov.

Rao, M. M.

1981-01-01

133

Solvent changeouts without plant shutdown  

SciTech Connect

For reasons of greater selectivity, lower regeneration energy requirements, reduced corrosivity and possible greater amine stability, MDEA continues to replace DEA in numerous selective H/sub 2/S removal applications. Solvent changeouts from DEA to MDEA often require no equipment modification, yet they are generally achieved by shutting down the plant, draining the old solvent, cleaning, and finally recharging with MDEA. However, in at least one plant, solvent changeout was done on the fly simply by periodically making up normal DEA losses with MDEA until the plant was finally operating on MDEA alone. Gradual solvent changeouts have the advantages of no lost production, no disposal problems with the environmentally-hazardous old solvent, no use and subsequent disposal of cleaning agents, and no additional manpower requirements. An advanced flowsheet simulation capability can suggest when such a procedure is feasible and, when it is, plant simulation can help to ensure that the solvent changeout is done reliably and with no production or cost penalties. GASPLANT-PLUS(TM) is currently the only commercial simulator having formulated solvent (mixed amine) capabilities within a fully flexible flowsheeting environment. After highlighting its technical foundations, they will compare GASPLANT-PLUS predictions with some commercial plant data and, through examples, they will show how solvent changeouts can be done gradually, without plant shutdown.

Vickery, D.J.; Campbell, S.W. (Taylor, Weiland and Associates, Inc., Potsdam, NY (US))

1988-01-01

134

Chemical reactivity: Inverse solvent design  

NASA Astrophysics Data System (ADS)

Choosing a solvent for a particular reaction is often a matter of personal preference or the result of limited screening. Now, a computational method allows identification of a solvent that will enhance the kinetics of a reaction prior to running a wet experiment.

Truhlar, Donald G.

2013-11-01

135

SOLV-DB: Solvents Database  

NSDL National Science Digital Library

The purpose of SOLV-DB is to help you find a wide variety of data on solvents quickly and easily, including health and safety data, chemical and physical data, regulatory responsibilities, and environmental fate information. SOLV-DB is maintained by the National Center for Manufacturing Sciences and is considered a "one-stop source for solvents data."

2008-08-27

136

Laboratory solvent reuse -- Liquid chromatography  

SciTech Connect

The objective of this work was to develop a method for reduction of waste solvent in the Process Engineering Chemistry Laboratory. The liquid chromatographs are the largest generators of explosive-contaminated waste in the laboratory. We developed a successful process for the reuse of solvents from the liquid chromatographs and demonstrated the utility of the process in the assay of hexanitrostilbene.

Quinlin, W.T.; Schaffer, C.L.

1992-11-01

137

Solvent Retention and Fibre Chemistry.  

National Technical Information Service (NTIS)

The aim of this study was to understand in which way different chemical and physical treatments affect the solvent retention properties of pulps used in the middle layer of folding boxboard. The solvent retention properties of the treated pulps were exami...

M. Rantanen

2003-01-01

138

Weak decay of /?-hypernuclei  

NASA Astrophysics Data System (ADS)

In this review we discuss the present status of strange nuclear physics, with special attention to the weak decay of ?-hypernuclei. The models proposed for the evaluation of the ? decay widths are summarized and their results are compared with the data. The rates ? NM=? n+? p (+? 2) , ??0 and ??- are well explained by several calculations. Despite the intensive investigations of the last years, the main open problem remains a sound theoretical interpretation of the large experimental values of the ratio ?n/ ?p. However, the large uncertainties involved in the experimental determination of the ratio do not allow to reach any definitive conclusion. The ?n/ ?p puzzle is strongly related to the so-called ? I=1/2 rule on the isospin change in the non-mesonic decay, whose possible violation cannot be established at present, again due to the insufficient precision of the data. Although recent works offer a step forward in the solution of the puzzle, further efforts (especially on the experimental side) must be invested in order to understand the detailed dynamics of the non-mesonic decay. Even if, by means of single nucleon spectra measurements, the error bars on ?n/ ?p have been considerably reduced very recently at KEK (however, with central data compatible with older experiments), a clean extraction of ?n/ ?p is needed. What is missing at present, but planned for the next future, are measurements of (1) nucleon energy spectra in double coincidence and (2) nucleon angular correlations: such observations allow to disentangle the nucleons produced in one- and two-body induced decays and lead to a direct determination of ?n/ ?p. Notably, the two-body component of the non-mesonic decay rates has not been measured yet, due to the too low counting rates expected for a coincidence experiment. For the asymmetric non-mesonic decay of polarized hypernuclei the situation is even more puzzling. Indeed, strong inconsistencies appear already among data. A recent experiment obtained a positive intrinsic ? asymmetry parameter, a?, for ?5H?e. This is in complete disagreement with a previous measurement, which obtained a large and negative a? for p-shell hypernuclei, and with theory, which predicts a negative value moderately dependent on nuclear structure effects. Also in this case, improved experiment establishing with certainty the sign and magnitude of a? for s- and p-shell hypernuclei will provide a guidance for a deeper understanding of hypernuclear dynamics and decay mechanisms.

Alberico, W. M.; Garbarino, G.

2002-10-01

139

Solvent influence on base stacking.  

PubMed Central

In this paper we present a detailed analysis of the base-stacking phenomenon in different solvents, using nanosecond molecular dynamics simulations. The investigation focuses on deoxyribo- and ribodinucleoside monophosphates in aqueous and organic solutions. Organic solvents with a low dielectric constant, such as chloroform, and solvents with intermediate dielectric constants, such as dimethyl sulfoxide and methanol, were analyzed. This was also done for water, which is highly polar and has a high dielectric constant. Structural parameters such as the sugar puckering and the base-versus-base orientations, as well as the energetics of the solute-solvent interactions, were examined in the different solvents. The obtained data demonstrate that base stacking is favored in the high dielectric aqueous solution, followed by methanol and dimethyl sulfoxide with intermediate dielectric constants, and chloroform, with a low dielectric constant.

Norberg, J; Nilsson, L

1998-01-01

140

6. Coordination and control.  

PubMed

Any complex operation requires a system for management. In most societies, disaster management is the responsibility of the government. Coordination and control is a system that provides the oversight for all of the disaster management functions. The roles and responsibilities of a coordination and control centre include: (1) planning; (2) maintenance of inventories; (3) activation of the disaster response plan; (4) application of indicators of function; (5) surveillance; (6) information management; (7) coordination of activities of the BSFs; (8) decision-making; (9) priority setting; (10) defining overarching goal and objectives for interventions; (11) applying indicators of effectiveness; (12) applying indicators of benefit and impact; (13) exercising authority; (14) managing resources; (15) initiating actions; (16) preventing influx of unneeded resources; (17) defining progress; (18) providing information; (19) liasing with responding organisations; and (20) providing quality assurance. Coordination and control is impossible without communications. To accomplish coordination and control, three factors must be present: (1) mandate; (2) power and authority; and (3) available resources. Coordination and control is responsible for the evaluation of the effectiveness and benefits/impacts of all interventions. Coordination and control centres (CCCs) are organised hierarchically from the on-scene CCCs (incident command) to local provincial to national CCCs. Currently, no comprehensive regional and international CCCs have been universally endorsed. Systems such as the incident command system, the unified command system, and the hospital incident command system are described as are the humanitarian reform movement and the importance of coordination and control in disaster planning and preparedness. PMID:24785803

2014-05-01

141

Social Postural Coordination  

ERIC Educational Resources Information Center

The goal of the current study was to investigate whether a visual coupling between two people can produce spontaneous interpersonal postural coordination and change their intrapersonal postural coordination involved in the control of stance. We examined the front-to-back head displacements of participants and the angular motion of their hip and…

Varlet, Manuel; Marin, Ludovic; Lagarde, Julien; Bardy, Benoit G.

2011-01-01

142

Heliospheric coordinate systems  

Microsoft Academic Search

This article gives an overview and reference to the most common coordinate systems currently used in space science. While coordinate systems used in near-Earth space physics have been described in previous work we extend that description to systems used for physical observations of the Sun and the planets and to systems based on spacecraft location. For all systems, we define

M. Fränz; D. Harper

2002-01-01

143

Solution Phase Measurement of Both Weak Sigma and C-H---X- Hydrogen Bonding Interactions in Synthetic Anion Receptors  

SciTech Connect

A series of tripodal receptors preorganize electron-deficient aromatic rings to bind halides in organic solvents using weak sigma anion-to-arene interactions or C-H---X- hydrogen bonds. 1H NMR spectroscopy proves to be a powerful technique for quantifying binding in solution, and determining the interaction motifs, even in cases of weak binding.

Berryman, Mr. Orion B. [University of Oregon; Sather, Mr. Aaron C [University of Oregon; Hay, Benjamin [ORNL; Meisner, Mr. Jeffrey S. [University of Oregon; Johnson, Prof. Darren W. [University of Oregon

2008-01-01

144

Solvent degradation products in nuclear fuel processing solvents  

SciTech Connect

The Savannah River Plant uses a modified Purex process to recover enriched uranium and separate fission products. This process uses 7.5% tri-n-butyl phosphate (TBP) dissolved in normal paraffin hydrocarbons for the solvent extraction of a nitric acid solution containing the materials to be separated. Periodic problems in product decontamination result from solvent degradation. A study to improve process efficiency has identified certain solvent degradation products and suggested mitigation measures. Undecanoic acid, lauric acid, and tridecanoic acid were tentatively identified as diluent degradation products in recycle solvent. These long-chain organic acids affect phase separation and lead to low decontamination factors. Solid phase extraction (SPE) was used to concentrate the organic acids in solvent prior to analysis by high performance liquid chromatography (HPLC). SPE and HPLC methods were optimized in this work for analysis of decanoic acid, undecanoic acid, and lauric acid in solvent. Accelerated solvent degradation studies with 7.5% TBP in normal paraffin hydrocarbons showed that long-chain organic acids and long-chain alkyl butyl phosphoric acids are formed by reactions with nitric acid. Degradation of both tributyl phosphate and hydrocarbon can be minimized with purified normal paraffin replacing the standard grade presently used. 12 refs., 1 fig., 3 tabs.

Shook, H.E. Jr.

1988-06-01

145

COMPUTER AIDED SOLVENT DESIGN FOR THE ENVIRONMENT  

EPA Science Inventory

Solvent substitution is an effective and useful means of eliminating the use of harmful solvents, but finding substitute solvents which are less harmful and as effective as currently used solvents presents significant difficulties. Solvent substitution is a form of reverse engin...

146

Orthographic star coordinates.  

PubMed

Star coordinates is a popular projection technique from an nD data space to a 2D/3D visualization domain. It is defined by setting n coordinate axes in the visualization domain. Since it generally defines an affine projection, strong distortions can occur: an nD sphere can be mapped to an ellipse of arbitrary size and aspect ratio. We propose to restrict star coordinates to orthographic projections which map an nD sphere of radius r to a 2D circle of radius r. We achieve this by formulating conditions for the coordinate axes to define orthographic projections, and by running a repeated non-linear optimization in the background of every modification of the coordinate axes. This way, we define a number of orthographic interaction concepts as well as orthographic data tour sequences: a scatterplot tour, a principle component tour, and a grand tour. All concepts are illustrated and evaluated with synthetic and real data. PMID:24051828

Lehmann, Dirk J; Theisel, Holger

2013-12-01

147

Solvent effect on acid salt of dichloroacetic acid containing short and asymmetric OH…O bond  

NASA Astrophysics Data System (ADS)

The IR and 1H NMR spectra are reported for tetra-n-butylammonium bis-dichloroacetate in five dry aprotic solvents of different polarity (?=2.27 - 64.4) and basicity (DN= 0.1 - 15.1). Both the integrated intensity (A) and the centre of gravity ( overline?) of continuous absorption show weak dependence upon solvent used. The chemical shift (?) depends on the proton acceptor properties of solvents and is consistent with an equilibrium (BU) 4NA + AH ? (BU) 4N(AHA). The weak dependence of A and overline? upon the solvent polarity is consistent with the single minimum energy surface postulated in the literature for the strong OHO bonds.

Dega-Szafran, Z.; Szafran, M.

1986-03-01

148

EXPERIENCES IN DESIGNING SOLVENTS FOR THE ENVIRONMENT  

EPA Science Inventory

To meet the great need of replacing many harmful solvents commonly used by industry and the public with environmentally benign substitute solvents, the PARIS II solvent design software has been developed. Although the difficulty of successfully finding replacements increases with...

149

Caustic-Side Solvent Extraction Solvent-Composition Recommendation  

SciTech Connect

The U.S. Department of Energy has selected caustic-side solvent extraction as the preferred cesium removal technology for the treatment of high-level waste stored at the Savannah River Site. Data for the solubility of the extractant, calix[4]arene-bis(tert-octyl benzo-crown-6), acquired and reported for the Salt Processing Program down-select decision, showed the original solvent composition to be supersaturated with respect to the extractant. Although solvent samples have been observed for approximately 1 year without any solids formation, work was completed to define a new solvent composition that was thermodynamically stable with respect to solids formation and to expand the operating temperature with respect to third-phase formation. Chemical and physical data as a function of solvent component concentrations were collected. The data included calix[4]arene-bis(tert-octyl benzo-crown-6) solubility; cesium distribution ratio under extraction, scrub, and strip conditions; flow sheet robustness; temperature range of third-phase formation; dispersion numbers for the solvent against waste simulant, scrub and strip acids, and sodium hydroxide wash solutions; solvent density; viscosity; and surface and interfacial tension. These data were mapped against a set of predefined performance criteria. The composition of 0.007 M calix[4]arene-bis(tert-octyl benzo-crown-6), 0.75 M 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol, and 0.003 M tri-n-octylamine in the diluent Isopar{reg_sign} L provided the best match between the measured properties and the performance criteria. Therefore, it is recommended as the new baseline solvent composition.

Klatt, L.N.

2002-05-09

150

Solvent degradation products in nuclear fuel processing solvents  

Microsoft Academic Search

The Savannah River Plant uses a modified Purex process to recover enriched uranium and separate fission products. This process uses 7.5% tri-n-butyl phosphate (TBP) dissolved in normal paraffin hydrocarbons for the solvent extraction of a nitric acid solution containing the materials to be separated. Periodic problems in product decontamination result from solvent degradation. A study to improve process efficiency has

Shook; H. E. Jr

1988-01-01

151

Experimental investigations of weak definite and weak indefinite noun phrases  

PubMed Central

Definite noun phrases typically refer to entities that are uniquely identifiable in the speaker and addressee’s common ground. Some definite noun phrases (e.g. the hospital in Mary had to go the hospital and John did too) seem to violate this uniqueness constraint. We report six experiments that were motivated by the hypothesis that these “weak definite” interpretations arise in “incorporated” constructions. Experiments 1-3 compared nouns that seem to allow for a weak definite interpretation (e.g. hospital, bank, bus, radio) with those that do not (e.g. farm, concert, car, book). Experiments 1 and 2 used an instruction-following task and picture-judgment task, respectively, to demonstrate that a weak definite need not uniquely refer. In Experiment 3 participants imagined scenarios described by sentences such as The Federal Express driver had to go to the hospital/farm. The imagined scenarios following weak definite noun phrases were more likely to include conventional activities associated with the object, whereas following regular nouns, participants were more likely to imagine scenarios that included typical activities associated with the subject; similar effects were observed with weak indefinites. Experiment 4 found that object-related activities were reduced when the same subject and object were used with a verb that does not license weak definite interpretations. In Experiment 5, a science fiction story introduced an artificial lexicon for novel concepts. Novel nouns that shared conceptual properties with English weak definite nouns were more likely to allow weak reference in a judgment task. Experiment 6 demonstrated that familiarity for definite articles and anti- familiarity for indefinite articles applies to the activity associated with the noun, consistent with predictions made by the incorporation analysis.

Klein, Natalie M.; Gegg-Harrison, Whitney M.; Carlson, Greg N.; Tanenhaus, Michael K.

2013-01-01

152

Local Coordinates Model  

NSDL National Science Digital Library

The Local Coordinates model displays the position of a star in local (Altitude/Azimuth) coordinates. The horizon is shown along with the four cardinal directions (N, E, S, and W). The latitude of the observer is set at 35.5 degrees which sets the location of the north celestial pole (teal) relative to the northern horizon. The position of the star can be changed by using the Altitude and Azimuth sliders. The Local Coordinates model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_Local Coordinates.jar file will run the program if Java is installed. EJS is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models.

Belloni, Mario; Timberlake, Todd

2010-01-02

153

Understanding social motor coordination.  

PubMed

Recently there has been much interest in social coordination of motor movements, or as it is referred to by some researchers, joint action. This paper reviews the cognitive perspective's common coding/mirror neuron theory of joint action, describes some of its limitations and then presents the behavioral dynamics perspective as an alternative way of understanding social motor coordination. In particular, behavioral dynamics' ability to explain the temporal coordination of interacting individuals is detailed. Two experiments are then described that demonstrate how dynamical processes of synchronization are apparent in the coordination underlying everyday joint actions such as martial art exercises, hand-clapping games, and conversations. The import of this evidence is that emergent dynamic patterns such as synchronization are the behavioral order that any neural substrate supporting joint action (e.g., mirror systems) would have to sustain. PMID:20817320

Schmidt, R C; Fitzpatrick, Paula; Caron, Robert; Mergeche, Joanna

2011-10-01

154

Resisting Weakness of the Will  

PubMed Central

I develop an account of weakness of the will that is driven by experimental evidence from cognitive and social psychology. I will argue that this account demonstrates that there is no such thing as weakness of the will: no psychological kind corresponds to it. Instead, weakness of the will ought to be understood as depletion of System II resources. Neither the explanatory purposes of psychology nor our practical purposes as agents are well-served by retaining the concept. I therefore suggest that we ought to jettison it, in favour of the vocabulary and concepts of cognitive psychology.

Levy, Neil

2012-01-01

155

Weak-shock reflection factors  

SciTech Connect

The purpose of this paper is to compare reflection factors for weak shocks from various surfaces, and to focus attention on some unsolved questions. Three different cases are considered: square-wave planar shock reflection from wedges; square-wave planar shock reflection from cylinders; and spherical blast wave reflection from a planar surface. We restrict ourselves to weak shocks. Shocks with a Mach number of M{sub O} < 1.56 in air or with an overpressure of {Delta}{sub PI} < 25 psi (1.66 bar) under normal ambient conditions are called weak.

Reichenbach, H. [Ernst Mach Inst., Freiburg (Germany); Kuhl, A.L. [Lawrence Livermore National Lab., El Segundo, CA (United States)

1993-09-07

156

Coordination infrastructures for mobile agents  

Microsoft Academic Search

The mobile agent technology is gaining more and more interest in the distributed systems community. In this context, suitable coordination models are needed to handle the coordination, both among mobile agents and between agents and Internet resources. This paper presents two coordination infrastructures that follow two different coordination models: Aglets, based on the message-passing coordination model, and Mobile Agent Reactive

Giacomo Cabri; Letizia Leonardi; Franco Zambonelli

2001-01-01

157

SOLV-DB: Solvents Data  

DOE Data Explorer

SOLV-DB provides a specialized mix of information on commercially available solvents. The development of the database was funded under the Strategic Environmental Research and Development Program (SERDP) with funds from EPA and DOE's Office of Industrial Technologies in EE. The information includes: • Health and safety considerations involved in choosing and using solvents • Chemical and physical data affecting the suitability of a particular solvent for a wide range of potential applications • Regulatory responsibilities, including exposure and effluent limits, hazard classification status with respect to several key statutes, and selected reporting requirements • Environmental fate data, to indicate whether a solvent is likely to break down or persist in air or water, and what types of waste treatment techniques may apply to it • CAS numbers (from Chemical Abstracts Service) and Sax Numbers (from Sax, et.al., Dangerous Properties of Industrial Materials) Supplier Information See help information at http://solvdb.ncms.org/welcome.htm (Specialized Interface)

158

DOE solvent handbook information sheet.  

National Technical Information Service (NTIS)

Solvents and cleaners are used in the Department of Defense (DOD) and the Department of Energy-Defense Program (DOE-DP) maintenance facilities for removing wax, grease, oil, carbon, machining fluids, solder fluxes, mold releases, and other contaminants be...

A. A. Chavez

1992-01-01

159

Nonadiabatic dynamics of electron transfer in solution: Explicit and implicit solvent treatments that include multiple relaxation time scales  

NASA Astrophysics Data System (ADS)

The development of efficient theoretical methods for describing electron transfer (ET) reactions in condensed phases is important for a variety of chemical and biological applications. Previously, dynamical dielectric continuum theory was used to derive Langevin equations for a single collective solvent coordinate describing ET in a polar solvent. In this theory, the parameters are directly related to the physical properties of the system and can be determined from experimental data or explicit molecular dynamics simulations. Herein, we combine these Langevin equations with surface hopping nonadiabatic dynamics methods to calculate the rate constants for thermal ET reactions in polar solvents for a wide range of electronic couplings and reaction free energies. Comparison of explicit and implicit solvent calculations illustrates that the mapping from explicit to implicit solvent models is valid even for solvents exhibiting complex relaxation behavior with multiple relaxation time scales and a short-time inertial response. The rate constants calculated for implicit solvent models with a single solvent relaxation time scale corresponding to water, acetonitrile, and methanol agree well with analytical theories in the Golden rule and solvent-controlled regimes, as well as in the intermediate regime. The implicit solvent models with two relaxation time scales are in qualitative agreement with the analytical theories but quantitatively overestimate the rate constants compared to these theories. Analysis of these simulations elucidates the importance of multiple relaxation time scales and the inertial component of the solvent response, as well as potential shortcomings of the analytical theories based on single time scale solvent relaxation models. This implicit solvent approach will enable the simulation of a wide range of ET reactions via the stochastic dynamics of a single collective solvent coordinate with parameters that are relevant to experimentally accessible systems.

Schwerdtfeger, Christine A.; Soudackov, Alexander V.; Hammes-Schiffer, Sharon

2014-01-01

160

Equatorial Coordinates Model  

NSDL National Science Digital Library

The Equatorial Coordinates model displays the position of a star in equatorial (Right Ascension/Declination --- RA/Dec) coordinates. The horizon is shown along with the four cardinal directions (N, E, S, and W). The Latitude slider changes the latitude of the observer which is shown by the change in the (teal) celestial pole relative to the northern horizon. The position of the star can be changed by using the Right Ascension and Declination sliders. Once these coordinates are selected, pressing the play button will put the star, celestial grid, and the equatorial coordinates in motion to simulate the 23 hour and 56 minute motion of stars in the night sky. Equatorial Coordinates model is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_astronomy_EquatorialCoordinates.jar file will run the program if Java is installed. You can modify this simulation if you have EJS installed by right-clicking within the plot and selecting "Open EJS Model" from the pop-up menu item.

Belloni, Mario; Timberlake, Todd

2009-11-14

161

Conformational transitions of weak polyacids grafted to nanoparticles  

NASA Astrophysics Data System (ADS)

The charge distribution on polyelectrolytes is a key factor, which controls their conformation and interactions. In weak polyelectrolytes, this distribution is determined by a number of factors, including the solvent conditions and local environment. In this work, we investigate charge distributions of chains end-grafted on a spherical nanoparticle in a salt solution, using grand canonical titration Monte Carlo simulations of a coarse-grained polymer model. In this approach, the ionization state of each polymer bead fluctuates based on the dissociation constant, pH of the solution, and interactions with other particles in the system. We determine charge and polymer conformations as functions of the pH and solvent quality. We compare the results to a fixed charge model and also investigate the role of grafting density and the effect of curvature on the film morphologies.

Barr, S. A.; Panagiotopoulos, A. Z.

2012-10-01

162

MOFs by solvent free high temperature synthesis exemplified by ?3[Eu 3(Tz ?) 6(Tz ?H) 2  

NASA Astrophysics Data System (ADS)

Solvent free synthesis methods of solid state chemistry can be utilized to synthesize MOFs (metal organic frameworks) and moreover render frameworks accessible that cannot be obtained from classic solvent reactions. Focusing on nitrogen coordinated rare earth compounds amides and nitriles can be successfully obtained from melts of the referring neutral N donor ligands. Exclusion of solvents prevents solvent co-coordination so that Ln-N-MOFs free of oxygen coordination become available. The success of this synthesis strategy is represented by the synthesis of ?3[Eu 3(Tz ?) 6(Tz ?H) 2], Tz ?H = 1 H-1,2,3-triazole, C 2N 3H 3, Tz ?- = 1,2,3-triazolate anion, the first 4f network of the aromatic N-heterocycle 1,2,3-triazole. The compound contains divalent europium and adopts a unique (12,4)-net.

Müller-Buschbaum, Klaus; Mokaddem, Yassin

2008-04-01

163

Effect of solvent on the exchange of ethylene for propylene on cis-PtCl2(C3H6)(TPPTS), TPPTS = P(mC6H4SO3Na)3  

Microsoft Academic Search

To further understand the effect of water as a solvent in organometallic reactions, the lability of ?-alkenes coordinated to platinum(II) phosphine complexes has been studied in water and chloroform as a comparison of solvent effects on the exchange kinetics and alkene complex stability. H NMR techniques with both deuterated chloroform and a deuterium oxide\\/deuterated methanol mixture as solvent systems were

Jeffrey Dudziak; Jim D. Atwood

2011-01-01

164

Thermal conductivities of Wilsonville solvent and Wilsonville solvent\\/Illinois No. 6 coal slurry. [Wilsonville solvent  

Microsoft Academic Search

Thermal conductivities of a Wilsonville solvent and of a slurry prepared from this solvent and Illinois No. 6 coal have been measured at temperatures from 295 up to 500 K. With increasing temperature, the thermal conductivity varied from 1.23 to 1.02 mW cm⁻¹ K⁻¹ (296 to 438 K) and from 1.51 to 1.02 mW cm⁻¹ K⁻¹ (295 to 505 K)

J. H. Wilson; J. E. Mrochek; J. K. Johnson

1984-01-01

165

17  Macrocyclic coordination chemistry  

Microsoft Academic Search

Highlights include the design of a dicopper(II) cryptate that can be used for the fluorescent detection of dicarboxylate anions in aqueous solution, the translocation of copper(II) centres within a macrocycle to detect imidazole- based moieties, and the design of a cyclohexyl-1,2-diamine derived bis(binaphthyl) macrocycle that demonstrates enantioselectivity in the fluorescent recognition of mandelic acid. The activation of acetonitrile solvent by

Leroy Cronin

2005-01-01

166

Dissolution of coal in solvents  

SciTech Connect

Experimental studies were effected in a 1-liter batch reactor to determine the role of the solvent and temperature on the dissolution of a Kentucky No. 9 coal. The goal was to increase the dissolution yield, defined as conversion of coal to pyridine-soluble material, while decreasing the hydrogen demand. The experiments were carried out in the absence of hydrogen gas. The solvent and coal were heated at a constant rate of temperature rise to 300 to 400/sup 0/C and held at a constant temperature for periods of 0 to 50 minutes before rapidly quenching the reaction mixture. 2-Methylnaphalene, 1,2,3,4-tetrahydronaphthalene (tetralin), p-cresol or ..beta..-naphthol, and ..gamma..-picoline were used in different ratios as the solvent. These compounds represented, respectively, the polycondensed aromatics, hydroaromatics (hydrogen donor), monophenols, and basic nitrogen compounds found in coal liquefaction recycle solvents. Dissolution yield of the coal reached a maximum in a solvent containing equal parts of 2-methylnaphthalene and tetralin. The H/C ratio of the preasphaltenes remained virtually constant when the tetralin content ranged from 20 to 65 wt % in mixtures with 2-methylnaphthalene. A slight increase was noted when pure tetralin was the solvent. Addition of small amounts of ..beta..-naphthol and ..gamma..-picoline to a 1:4 weight ratio of tetralin and 2-methylnaphthalene improved the dissolution yield. Coal was dissolved with no or minor chemical reactions up to the temperature of approx. 340/sup 0/C in a solvent containing 46.1 wt % tetralin, 46.1 wt % 2-methylnaphthalene, 4.9 wt % ..beta..-naphthol, and 2.9 wt % ..gamma..-picoline. Beyond this temperature dissolution yield increased exponentially typical of thermal cracking reactions.

Ebnesajjad, S.

1982-01-01

167

Properties of ionic liquid solvents for catalysis  

Microsoft Academic Search

Ionic liquids are good solvents for catalytic reactions. The rational selection of the appropriate ionic liquid solvent for a particular reaction requires general knowledge of the properties of ionic liquids, and the details of some properties of the specific ionic liquid solvents being considered. The solvent properties of ionic liquids that are relevant to catalysis are discussed, and sources of

John S Wilkes

2004-01-01

168

NCMS solvent substitution and material compatibility databases  

Microsoft Academic Search

The NCMS Solvent Database collects information on alternatives to ODC-based solvents used in electronics manufacturing. The database contains over 320 pure solvents and trade name mixtures. Each record includes 15 fields of environmental fate, 31 fields of health and safety, 21 fields of regulatory status, 36 fields of chemical\\/physical properties, and 19 fields of descriptive and supplier data. The Solvent

M. R. Wixom

1994-01-01

169

Noncommutativity in weakly curved background by canonical methods  

SciTech Connect

Using the canonical method, we investigate the Dp-brane world-volume noncommutativity in a weakly curved background. The term 'weakly curved' means that, in the leading order, the source of nonflatness is an infinitesimally small Kalb-Ramond field B{sub {mu}{nu}}, linear in coordinate, while the Ricci tensor does not contribute, being an infinitesimal of the second order. On the solution of boundary conditions, we find a simple expression for the space-time coordinates in terms of the effective coordinates and momenta. This basic relation helped us to prove that noncommutativity appears only on the world sheet boundary. The noncommutativity parameter has a standard form, but with the infinitesimally small and coordinate-dependent antisymmetric tensor B{sub {mu}{nu}}. This result coincides with that obtained on the group manifolds in the limit of the large level n of the current algebra. After quantization, the algebra of the functions on the Dp-brane world volume is represented with the Kontsevich star product instead of the Moyal one in the flat background.

Davidovic, Lj.; Sazdovic, B. [Institute of Physics, University of Belgrade, 11001 Belgrade, P.O. Box 57 (Serbia)

2011-03-15

170

Structure modulation of manganese coordination polymers consisting of 1,4-naphthalene dicarboxylate and 1,10-phenanthroline.  

PubMed

Three new manganese coordination polymers, {[Mn2(1,4-NDC)2(phen)2](H2O)}n (1), [Mn2(1,4-NDC)2(phen)(H2O)]n (2) and {[Mn4(1,4-NDC)4(phen)4](DMF)2}n (3) (1,4-H2NDC = 1,4-naphthalene dicarboxylic acid; phen = 1,10-phenanthroline; DMF = N,N-dimethylformamide), have been synthesized solvo/hydrothermally. 1,4-NDC(2-) ligands adopt different coordination modes under different solvents and concentrations which promotes different crystal structure formation. X-ray crystal structural data reveal that compounds 1, 2 and 3 crystallize in monoclinic space groups C2/c, P21/c and C2/c, respectively. Compound 1 has Mn2 dimers connected by 1,4-NDC(2-) linkers, packing into a 2D structure in a grid pattern. Compound 2 has a three-dimensional (3D) structure which is constructed by Mn2 dimers and 1,4-NDC(2-) linkers. Each MnO4N2 node of compound 3 is linked to another by 1,4-NDC(2-) ligands to form a two-dimensional (2D) structure. Variable-temperature magnetic susceptibilities of compounds 1-3 exhibit overall weak antiferromagnetic coupling between the adjacent Mn(II) ions. PMID:24756312

Lou, Yongbing; Wang, Jingjing; Tao, Yinhua; Chen, Jinxi; Mishima, Akio; Ohba, Masaaki

2014-06-14

171

Solvent effects on the resonance Raman spectra of bacteriochlorophyll a cation radical  

Microsoft Academic Search

Resonance Raman (RR) spectra were measured for the cation radical of bacteriochlorophyll a in acetone, methanol, dichloromethane and mixed solvents of acetone and methanol. The ring-breathing (Ca-Cm stretching) frequency of the radical (abbreviated as vr+) was observed at 1601 cm?1 in acetone (forming a penta-coordinated monomer), at 1587 cm?1 in a methanol (forming a hexa-coordinated monomer) and at 1600 cm?1

Yasuhito Misono; Ei-Ichi Nishizawa; Leenawaty Limantara; Yasushi Koyama; Koichi Itoh

1995-01-01

172

Coordinate Standard Measurement Development  

SciTech Connect

A Shelton Precision Interferometer Base, which is used for calibration of coordinate standards, was improved through hardware replacement, software geometry error correction, and reduction of vibration effects. Substantial increases in resolution and reliability, as well as reduction in sampling time, were achieved through hardware replacement; vibration effects were reduced substantially through modification of the machine component dampening and software routines; and the majority of the machine's geometry error was corrected through software geometry error correction. Because of these modifications, the uncertainty of coordinate standards calibrated on this device has been reduced dramatically.

Hanshaw, R.A.

2000-02-18

173

Peripheral facial weakness (Bell's palsy).  

PubMed

Peripheral facial weakness is a facial nerve damage that results in muscle weakness on one side of the face. It may be idiopathic (Bell's palsy) or may have a detectable cause. Almost 80% of peripheral facial weakness cases are primary and the rest of them are secondary. The most frequent causes of secondary peripheral facial weakness are systemic viral infections, trauma, surgery, diabetes, local infections, tumor, immune disorders, drugs, degenerative diseases of the central nervous system, etc. The diagnosis relies upon the presence of typical signs and symptoms, blood chemistry tests, cerebrospinal fluid investigations, nerve conduction studies and neuroimaging methods (cerebral MRI, x-ray of the skull and mastoid). Treatment of secondary peripheral facial weakness is based on therapy for the underlying disorder, unlike the treatment of Bell's palsy that is controversial due to the lack of large, randomized, controlled, prospective studies. There are some indications that steroids or antiviral agents are beneficial but there are also studies that show no beneficial effect. Additional treatments include eye protection, physiotherapy, acupuncture, botulinum toxin, or surgery. Bell's palsy has a benign prognosis with complete recovery in about 80% of patients, 15% experience some mode of permanent nerve damage and severe consequences remain in 5% of patients. PMID:24053080

Basi?-Kes, Vanja; Dobrota, Vesna Dermanovi?; Cesarik, Marijan; Matovina, Lucija Zadro; Madzar, Zrinko; Zavoreo, Iris; Demarin, Vida

2013-06-01

174

Weak Selection and Protein Evolution  

PubMed Central

The “nearly neutral” theory of molecular evolution proposes that many features of genomes arise from the interaction of three weak evolutionary forces: mutation, genetic drift, and natural selection acting at its limit of efficacy. Such forces generally have little impact on allele frequencies within populations from generation to generation but can have substantial effects on long-term evolution. The evolutionary dynamics of weakly selected mutations are highly sensitive to population size, and near neutrality was initially proposed as an adjustment to the neutral theory to account for general patterns in available protein and DNA variation data. Here, we review the motivation for the nearly neutral theory, discuss the structure of the model and its predictions, and evaluate current empirical support for interactions among weak evolutionary forces in protein evolution. Near neutrality may be a prevalent mode of evolution across a range of functional categories of mutations and taxa. However, multiple evolutionary mechanisms (including adaptive evolution, linked selection, changes in fitness-effect distributions, and weak selection) can often explain the same patterns of genome variation. Strong parameter sensitivity remains a limitation of the nearly neutral model, and we discuss concave fitness functions as a plausible underlying basis for weak selection.

Akashi, Hiroshi; Osada, Naoki; Ohta, Tomoko

2012-01-01

175

Self-assembled nanostructures of amphiphilic zinc(ii) salophen complexes: role of the solvent on their structure and morphology.  

PubMed

This contribution explores the effect of several solvent properties, such as volatility, polarity, and Lewis basicity on the formation of molecular self-assembled nanostructures in the solid state, obtained either by casting of related solutions or by complete solvent evaporation, using seven solvents representative of common classes of coordinating organic solvents, of an amphiphilic Zn(II) Schiff-base complex. In all cases, the existence of well-defined X-ray diffraction patterns, for both the cast and powder samples, indicates a strong tendency towards the molecular self-assembly of such complexes. While nanostructures formed in acetone, THF, pyridine, and DMF have a lamellar organization, those formed in ACN, ethanol, and DMSO exhibit a 2D columnar square structure. Field emission scanning electron microscopy analysis indicates that nanostructures formed in volatile acetone, THF, ACN, and ethanol solvents show a fibrous morphology, while those formed in less volatile pyridine, DMF, and DMSO have a ribbon appearance. Overall, the results indicate that while the formation of such nanostructures is independent of the Lewis basicity of the solvent, the solvent polarity affects their structure - more polar solvents favour higher symmetry structures - and the solvent volatility influences their morphology and ordering in the cast films - lower volatility of the solvent parallels the formation of much more ordered structures. Therefore, the appropriate choice of solvent allows control of the structure, morphology, and ordering of these molecular assemblies. PMID:24875135

Oliveri, Ivan Pietro; Malandrino, Graziella; Di Bella, Santo

2014-07-14

176

Solvent effects in polyelectrolyte adsorption: Computer simulations with explicit and implicit solvent  

Microsoft Academic Search

The adsorption of strongly charged polyelectrolyte chains to an oppositely charged planar surface is studied using computer simulation. In addition to an explicit solvent model, two implicit solvent models are considered: one where the solvent induces an implicit Lennard-Jones (ILJ) interaction between polymer sites and one where the solvent induces a many body interaction that depends on the solvent accessible

Govardhan Reddy; Arun Yethiraj

2010-01-01

177

Solvent leaching of tar sands  

SciTech Connect

Solvent flooding is the basis of a wide range of enhanced oil recovery methods, and has been shown to be a possible method of creating initial steam injectivity in tar sands. This paper presents a unique model of dissolution of a semi-solid bitumen, resulting from the injection of a solvent. The solution of the mathematical equations, describing this phenomena is discussed. Results, including a series of two-dimensional problems, are presented. Numerical aspects are addressed. It is shown that three dimensionless groups control the bitumen leaching process. In the absence of fluid flow, the dissolution of bitumen is governed by the Damkohler and solvent capacity numbers. In the absence of dissolution, the Peclet number governs miscible displacement in the fluid phase. This paper presents computational results for a series of two-dimensional problems for a five-spot flow geometry, showing the importance of the model developed.

Oguztoreli, M.; Faroqu, S.M.

1983-11-01

178

Solvent sensitive polymer composite structures  

NASA Astrophysics Data System (ADS)

In this paper we describe a composite system based on polystyrene colloidal nanoparticles assembled and embedded in an elastomeric matrix (polymer colloidal crystal, PCC), in the specific we have designed a PCC structure which displays an iridescent green color that can be attributed to the photonic crystal effect. This effect has been exploited to create a chemical sensor, in fact optical measurements have evidenced that the composite structure presents a different optical response as a function of the solvent applied on the surface. In particular we have demonstrated that the PCC possess, for specific solvents: (i) high sensitivity, (ii) fast response (less than 1s), and (iii) reversibility of the signal change. Finally preliminary results on the PCC have shown that this system can be also used as optical writing substrate using a specific solvent as ink, moreover an erasing procedure is also reported and discussed.

Chiappini, A.; Armellini, C.; Carpentiero, A.; Minati, L.; Righini, G. C.; Ferrari, M.

2013-11-01

179

Solvent-regenerated activated carbon  

SciTech Connect

This report summarizes the results of a University/Industry research project, sponsored by the New York State Energy Research and Development Authority and Fluids Design Corporation. The research project studied the solvent regeneration of activated carbon. Activate carbon was used to remove trace organics from aqueous streams, then regenerated by desorbing the adsorbates with organic solvents. The project included a survey of the potential applications in New York State industries, fundamental research on the adsorption/desorption phenomena, and design of a full-scale process. The economics of the full-scale process were evaluated and compared to alternate available technologies. The result of this work is a versatile process with attractive economics. A wide range of adsorbates and solvents were found to be acceptable for this process. The design methodologies are developed and the techniques for evaluating a new application are delineated. 13 refs., 12 figs., 4 tabs.

McLaughlin, H. (Fluids Design Corp., Troy, NY (USA))

1988-07-01

180

Sun Position (Polar Coordinates)  

NSDL National Science Digital Library

This applet shows the current (realtime) Sun position as seen from a polar view above the North pole. The elevation and azimuth of the Sun are given, and a brief description of celestial coordinates and celestial spheres is covered as well. A demonstration of this applet is available to download.

Giesen, Juergen

181

Chaos as coordination technology  

Microsoft Academic Search

The need of supporting office work with suitable computer based tools implies the investigation of the deep aspects of cooperation within the office. Cooperation, to the extent that is made up of communication and coordination, can be fully characterized under the assumption that an office is a special linguistic game, constituted by a set of rules defining the conversations possible

F. De Cindio; G. De Michelis; C. Simone; R. Vassallo; A. M. Zanaboni

1986-01-01

182

Block coordination copolymers  

DOEpatents

The present invention provides compositions of crystalline coordination copolymers wherein multiple organic molecules are assembled to produce porous framework materials with layered or core-shell structures. These materials are synthesized by sequential growth techniques such as the seed growth technique. In addition, the invention provides a simple procedure for controlling functionality.

Koh, Kyoung Moo; Wong-Foy, Antek G; Matzger, Adam J; Benin, Annabelle I; Willis, Richard R

2012-11-13

183

Block coordination copolymers  

DOEpatents

The present invention provides compositions of crystalline coordination copolymers wherein multiple organic molecules are assembled to produce porous framework materials with layered or core-shell structures. These materials are synthesized by sequential growth techniques such as the seed growth technique. In addition, the invention provides a simple procedure for controlling functionality.

Koh, Kyoung Moo; Wong-Foy, Antek G.; Matzger, Adam J.; Benin, Annabelle I.; Willis, Richard R.

2012-12-04

184

Origins of Coordinate Searching.  

ERIC Educational Resources Information Center

Reviews the origins of post-coordinate searching and emphasizes that the focal point should be on the searcher, not on the item being indexed. Highlights include the history of the term information retrieval; edge notched punch cards; the "peek-a-boo" system; the Uniterm system; and using computers to search for information. (LRW)

Kilgour, Frederick G.

1997-01-01

185

Future Coordinated Universal Time  

Microsoft Academic Search

Coordinated Universal Time (UTC), created by adjusting International Atomic Time (TAI) by the appropriate number of leap seconds, is the uniform time scale that is the basis of most civil timekeeping in the world. The concept of a leap second was introduced to ensure that UTC would not differ by more than 0.9 seconds from UT1, the time determined by

Dennis D. McCarthy

2000-01-01

186

On Normal Coordinates.  

National Technical Information Service (NTIS)

The purpose of the paper is the effective transformation to normal coordinates of the system of linear differential equations Summation from k = 1 to n of (f sub jk)(D)(x sub k) = y sub j(t), (j=1,...,n) where D is the differential operator d/dt and the l...

B. V. Bulgakov

1968-01-01

187

Cosmology and the weak interaction  

NASA Technical Reports Server (NTRS)

The weak interaction plays a critical role in modern Big Bang cosmology. Two of its most publicized comological connections are emphasized: big bang nucleosynthesis and dark matter. The first of these is connected to the cosmological prediction of neutrine flavors, N(sub nu) is approximately 3 which in now being confirmed. The second is interrelated to the whole problem of galacty and structure formation in the universe. The role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure is demonstrated.

Schramm, David N.

1989-01-01

188

A Framework of Coordinated Defense  

Microsoft Academic Search

Coordinated defense in cyber warfare has emerged to protect information as assets through the use of technologies, policy, and best management practices for defending against coordinated attacks. However, combining massive security technologies, policies, procedures and security staff does not guarantee the effectiveness of defense. Without a well-defined and structured element of coordination, an organization can not stand firm during coordinated

Shuyuan Mary Ho

189

Learning and coordination: An overview  

Microsoft Academic Search

Adaptive learning techniques can automate the large-scale coordination of multi-agent systems and enhance their robustness in dynamic environments. This paper surveys several learning approaches that have been developed to address three different aspects of coordination, namely, learning coordination behavior, team learning, and the integrated learning of trust and reputation in order to facilitate coordination in open systems including collaborative systems

Myriam Abramson; Ranjeev Mittu

2011-01-01

190

Automated Solvent Seaming of Large Polyimide Membranes  

NASA Technical Reports Server (NTRS)

A solvent-based welding process enables the joining of precise, cast polyimide membranes at their edges to form larger precise membranes. The process creates a homogeneous, optical-quality seam between abutting membranes, with no overlap and with only a very localized area of figure disturbance. The seam retains 90 percent of the strength of the parent material. The process was developed for original use in the fabrication of wide-aperture membrane optics, with areal densities of less than 1 kg/m2, for lightweight telescopes, solar concentrators, antennas, and the like to be deployed in outer space. The process is just as well applicable to the fabrication of large precise polyimide membranes for flat or inflatable solar concentrators and antenna reflectors for terrestrial applications. The process is applicable to cast membranes made of CP1 (or equivalent) polyimide. The process begins with the precise fitting together and fixturing of two membrane segments. The seam is formed by applying a metered amount of a doped solution of the same polyimide along the abutting edges of the membrane segments. After the solution has been applied, the fixtured films are allowed to dry and are then cured by convective heating. The weld material is the same as the parent material, so that what is formed is a homogeneous, strong joint that is almost indistinguishable from the parent material. The success of the process is highly dependent on formulation of the seaming solution from the correct proportion of the polyimide in a suitable solvent. In addition, the formation of reliable seams depends on the deposition of a precise amount of the seaming solution along the seam line. To ensure the required precision, deposition is performed by use of an automated apparatus comprising a modified commercially available, large-format, ink-jet print head on an automated positioning table. The printing head jets the seaming solution into the seam area at a rate controlled in coordination with the movement of the positioning table.

Rood, Robert; Moore, James D.; Talley, Chris; Gierow, Paul A.

2006-01-01

191

Occupational neurotoxicology of organic solvents and solvent mixtures  

Microsoft Academic Search

The results of two field studies in painters and spray painters, the outcomes of examinations of workers with suspected work-related disease due to solvents, as well as data from an evaluation of an epidemiologic study in painters with confirmed occupational disease, are presented and discussed. The results of these studies and the experiences in occupational medicine in the Federal Republic

G TRIEBIG

1989-01-01

192

MICROBIOLOGY: Breathing with Chlorinated Solvents  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required: Chlorinated solvents, the carcinogenic agents that permeate the air in your dry cleaners, have accumulated in the groundwater because microorganisms in the soil do not break them down. Now Maymó-Gatell et al. have isolated the first bacterium that can metabolize trichloroethylene and perchloroethylene to the harmless compound ethene. Identification of the bacterium will potentially allow manipulation of the conditions underground to facilitate the natural destruction of chlorinated solvents.

Perry L. McCarty (Stanford University;Department of Civil Engineering)

1997-06-06

193

Solvent Influences on the Molecular Aggregation of Magnesium Aryloxides  

SciTech Connect

Magnesium aryloxides were prepared in a variety of solvents through the reaction of dibutyl magnesium with sterically varied aryl alcohols: 2,6-dimethylphenol (H-DMP), 2,6-diisopropylphenol (H-DIP), and 2,4,6-trichlorophenol (H-TCP). Upon using a sufficiently strong Lewis-basic solvent, the monomeric species Mg(DMP){sub 2}(py){sub 3} (1, py = pyridine), Mg(DIP){sub 2}(THF){sub 3}, (2a, THF = tetrahydrofuran) Mg(TCP){sub 2}(THF){sub 3} (3) were isolated. Each of these complexes possesses a five-coordinate magnesium that adopts a trigonal bipyramidal geometry. In the absence of a Lewis base, the reaction with H-DIP yields a soluble trinuclear complex, [Mg(DIP){sub 2}]{sub 3} (2b). The Mg metal centers in 2b adopt a linear arrangement with a four-coordinate central metal while the outer metal centers are reduced to just three-coordinate. Solution spectroscopic methods suggest that while 2b remains intact, the monomeric species (1, 2a, and 3) are involved in equilibria, which facilitate intermolecular ligand transfer.

ZECHMANN,CECILIA A.; BOYLE,TIMOTHY J.; RODRIGUEZ,MARK A.; KEMP,RICHARD A.

2000-07-14

194

Tokamak coordinate conventions: COCOS  

NASA Astrophysics Data System (ADS)

Dealing with electromagnetic fields, in particular current and related magnetic fields, yields "natural" physical vector relations in 3-D. However, when it comes to choosing local coordinate systems, the "usual" right-handed systems are not necessarily the best choices, which means that there are several options being chosen. In the magnetic fusion community such a difficulty exists for the choices of the cylindrical and of the toroidal coordinate systems. In addition many codes depend on knowledge of an equilibrium. In particular, the Grad-Shafranov axisymmetric equilibrium solution for tokamak plasmas, ?, does not depend on the sign of the plasma current Ip nor that of the magnetic field B0. This often results in ill-defined conventions. Moreover the sign, amplitude and offset of ? are of less importance, since the free sources in the equation depend on the normalized radial coordinate. The signs of the free sources, dp/d? and dF2/d? (p being the pressure, ? the poloidal magnetic flux and F=RB?), must be consistent to generate the current density profile. For example, RF and CD calculations (Radio Frequency heating and Current Drive) require an exact sign convention in order to calculate a co- or counter-CD component. It is shown that there are over 16 different coordinate conventions. This paper proposes a unique identifier, the COCOS convention, to distinguish between the 16 most-commonly used options. Given the present worldwide efforts towards code integration, the proposed new index COCOS defining uniquely the COordinate COnventionS required as input by a given code or module is particularly useful. As codes use different conventions, it is useful to allow different sign conventions for equilibrium code input and output, equilibrium being at the core of any calculations in magnetic fusion. Additionally, given two different COCOS conventions, it becomes simple to transform between them. The relevant transformations are described in detail.

Sauter, O.; Medvedev, S. Yu.

2013-02-01

195

New Ag(I)-containing coordination polymers generated from multidentate Schiff-base ligands.  

PubMed

The coordination chemistry of the multidentate Schiff-base ligands 2,5-bis(3-methylpyrazinyl)-3,4-diaza-2,4-hexadiene (L5) and 2,5-bis(pyrazinyl)-3,4-diaza-2,4-hexadiene (L6) with inorganic Ag(I) salts has been investigated. Six new Ag(I)-coordination polymers were prepared by solution reactions and fully characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffraction. [Ag(L5)]ClO(4).0.5CH(3)OH (1, orthorhombic, Fdd2; a = 20.0896(11) A, b = 48.224(3) A, c = 7.8432(4) A, Z = 16), [Ag(L5)]PF(6).0.5CH(3)OH (2, orthorhombic, Fdd2; a = 20.7255(11) A, b = 46.166(2) A, c = 8.4332(4) A, Z = 16), [Ag(L5)]SbF(6).0.5CH(3)OH (3, orthorhombic, Fdd2; a = 21.5481(11) A, b = 45.196(2) A, c = 8.7331(4) A, Z = 16), and [Ag(L5)](BF(4)).0.5CH(3)OH (4, orthorhombic, Fdd2; a = 19.8897(11) A, b = 48.358(3) A, c = 7.7491(5) A, Z = 16) were obtained by combination of L5 with AgClO(4).xH(2)O, AgPF(6), AgSbF(6), and AgBF(4), respectively, in a methylene chloride/methanol mixed solvent system. Compounds 1-4 are isostructural and feature noninterpenetrating three-dimensional zeolite-like networks. [Ag(4)(L6)(4)](PF(6))(4).CHCl(3) (5, tetragonal, Pc2; a = 16.1067(3) A, b = 16.1067(3) A, c = 14.4935(5) A, Z = 2) was generated from the reaction of L6 with AgPF(6) in a chloroform/ethanol mixed solvent system. It forms with a unique one-dimensional nanometer-tube that can be considered a new polymeric motif based on the [AgN5] coordination sphere. The tubes are square with crystallographic dimensions of 10.3 x 10.0 A. The tubes are further linked together through weak interpolymer C-H...F hydrogen bonding interactions into a novel H-bonded three-dimensional network containing square tubes, in which uncoordinated PF(6)(-) counterions and chloroform guest molecules are located. Compound 6 ([Ag(mu-C(6)H(6)N(2)O)](SO(3)CF(3)), monoclinic, P2(1)/c; a = 12.3435(6) A, b = 20.3548(10) A, c = 9.0861(5) A, Z = 8) was obtained by combination of AgSO(3)CF(3) and L6 in a methylene chloride/benzene mixed solvent system. In 6, 2-acetylpyrazine, which was generated from the hydrolysis reaction of L6 in the presence of CF(3)SO(3)(-) and a small quantity of water in solvent, chelates the Ag(I) centers through the carbonyl O-donor, and the vicinal pyrazine N-donor, furthermore, uses the para-N atoms to link other Ag(I) centers into one-dimensional zigzag chains. The triflate anions link the chains into a three-dimensional network by somewhat long Ag.O contacts. PMID:15332812

Dong, Yu-Bin; Zhao, Xia; Huang, Ru-Qi; Smith, Mark D; zur Loye, Hans-Conrad

2004-09-01

196

Charge State and Adduct Reduction in Electrospray Ionisation-Mass Spectrometry using Solvent Vapour Exposure  

Microsoft Academic Search

The benefits of lowering protein ion charge states in electrospray ionisation (ESI) have attracted recent interest. We describe a simple approach to decrease protein charge states by exposure of electrospray droplets to neutral solvent vapour, such as acetonitrile. The technique allows detection of weak non-covalent complexes, provides preferred charge states for MS\\/MS dissociation of protein complexes and has the added

Jonathan T. S. Hopper; Kleitos Sokratous; Neil J. Oldham

197

Solvents and Parkinson disease: A systematic review of toxicological and epidemiological evidence  

SciTech Connect

Parkinson disease (PD) is a debilitating neurodegenerative motor disorder, with its motor symptoms largely attributable to loss of dopaminergic neurons in the substantia nigra. The causes of PD remain poorly understood, although environmental toxicants may play etiologic roles. Solvents are widespread neurotoxicants present in the workplace and ambient environment. Case reports of parkinsonism, including PD, have been associated with exposures to various solvents, most notably trichloroethylene (TCE). Animal toxicology studies have been conducted on various organic solvents, with some, including TCE, demonstrating potential for inducing nigral system damage. However, a confirmed animal model of solvent-induced PD has not been developed. Numerous epidemiologic studies have investigated potential links between solvents and PD, yielding mostly null or weak associations. An exception is a recent study of twins indicating possible etiologic relations with TCE and other chlorinated solvents, although findings were based on small numbers, and dose–response gradients were not observed. At present, there is no consistent evidence from either the toxicological or epidemiologic perspective that any specific solvent or class of solvents is a cause of PD. Future toxicological research that addresses mechanisms of nigral damage from TCE and its metabolites, with exposure routes and doses relevant to human exposures, is recommended. Improvements in epidemiologic research, especially with regard to quantitative characterization of long-term exposures to specific solvents, are needed to advance scientific knowledge on this topic. -- Highlights: ? The potential for organic solvents to cause Parkinson's disease has been reviewed. ? Twins study suggests etiologic relations with chlorinated solvents and Parkinson's. ? Animal studies with TCE showed potential to cause damage to dopaminergic neurons. ? Need to determine if effects in animals are relevant to human exposure levels.

Lock, Edward A., E-mail: e.lock@ljmu.ac.uk [Liverpool John Moores University, School of Pharmacy and Biomolecular Sciences, Byrom Street, Liverpool (United Kingdom); Zhang, Jing [University of Washington, Department of Pathology, School of Medicine, Seattle, WA (United States)] [University of Washington, Department of Pathology, School of Medicine, Seattle, WA (United States); Checkoway, Harvey [University of Washington, Department of Environmental and Occupational Health Sciences, Seattle, WA (United States)] [University of Washington, Department of Environmental and Occupational Health Sciences, Seattle, WA (United States)

2013-02-01

198

Solvent accessibility of ruthenium(II) photosensitizers with cetyltrimethyl ammonium bromide  

NASA Astrophysics Data System (ADS)

Previously we have developed a luminescence deuterium isotope method for determining F, the degree of solvent accessibility, of bound photosensitizers. We probe the binding of several luminescent ?-diimine-ruthenium(II) complexes to the cationic surfactant cetyltrimethyl ammonium bromide (CTAB). Both strong and weak binding systems are observed. The F number method was adapted for the weakly bound case. However, this simple model fails to account for all of the effects, and the systems are clearly richer. Surprisingly, efficient shielding can occur under conditions where the sensitizer is only weakly bound. This effect is attributed to premicellar aggregates.

Snyder, Seth W.; Demas, J. N.; Degraff, B. A.

1988-04-01

199

Coordination polymer gels with important environmental and biological applications.  

PubMed

Coordination Polymer Gels (CPGs) constitute a subset of solid-like metal ion and bridging organic ligand structures (similar to metal-organic frameworks) that form multi-dimensional networks through a trapped solvent as a result of non-covalent interactions. While physical properties of these gels are similar to conventional high molecular weight organic polymer gels, coordination polymer gel systems are often fully reversible and can be assembled and disassembled in the presence of additional energy (heat, sonication, shaking) to give a solution of solvated gelators. Compared to gels resulting from purely organic self-assembled low molecular weight gelators, metal ions incorporated into the fibrilar networks spanning the bulk solvent can impart CPGs with added functionalities. The solid/liquid nature of the gels allows for species to migrate through the gel system and interact with metals, ligands, and the solvent. Chemosensing, catalysis, fluorescence, and drug-delivery applications are some of the many potential uses for these dynamic systems, taking advantage of the metal ion's coordination, the organic polydentate ligand's orientation and functionality, or a combination of these properties. By fine tuning these systems through metal ion and ligand selection and by directing self-assembly with external stimuli the rational synthesis of practical systems can be envisaged. PMID:23192282

Jung, Jong Hwa; Lee, Ji Ha; Silverman, Julian R; John, George

2013-02-01

200

Strong Representation of Weak Convergence.  

National Technical Information Service (NTIS)

It is well known that there is a big difference between the concepts of weak and strong convergence of random variables. In the area of limilting theory, it is of interest to study the difference as well as the link between the two concepts of convergence...

Z. D. Bai W. Q. Liang

1985-01-01

201

N-{Delta} weak transition  

SciTech Connect

A short review of the Rein-Sehgal and isobar models is presented. The attention is focused on the nucleon-{Delta}(1232) weak transition form-factors. The results of the recent re-analyses of the ANL and BNL bubble chamber neutrino-deuteron scattering data are discussed.

Graczyk, Krzysztof M. [Institute of Theoretical Physics, University of Wroclaw, pl. M. Borna 9, 50-204, Wroclaw (Poland)

2011-11-23

202

DOE solvent handbook information sheet  

Microsoft Academic Search

Solvents and cleaners are used in the Department of Defense (DOD) and the Department of Energy-Defense Program (DOE-DP) maintenance facilities for removing wax, grease, oil, carbon, machining fluids, solder fluxes, mold releases, and other contaminants before repairing or electroplating parts. Private industry also uses cleaners and degreasers for surface preparation of various metals. Growing environmental and worker safety concerns have

Chavez

1992-01-01

203

Improved Purex solvent scrubbing methods  

SciTech Connect

Studies of hydrazine and hydroxylamine salts as solvent scrubbing agents that can be decomposed into gases are summarized. Results from testing of countercurrent scrubbers and solid sorber columns that produce lesser amounts of permanent salts are reported. The status of studies of the acid-degradation of paraffin diluent and the options for removal of long-chain organic acids is given.

Mailen, J.C.; Tallent, O.K.

1984-01-01

204

Nanopapers for organic solvent nanofiltration.  

PubMed

Would it not be nice to have an organic solvent nanofiltration membrane made from renewable resources that can be manufactured as simply as producing paper? Here the production of nanofiltration membranes made from nanocellulose by applying a papermaking process is demonstrated. Manufacture of the nanopapers was enabled by inducing flocculation of nanofibrils upon addition of trivalent ions. PMID:24752201

Mautner, A; Lee, K-Y; Lahtinen, P; Hakalahti, M; Tammelin, T; Li, K; Bismarck, A

2014-06-01

205

Challenging conventional f-element separation chemistry - reversing uranyl(vi)/lanthanide(iii) solvent extraction selectivity.  

PubMed

The water soluble tetradentate Schiff base, N,N'-bis(5-sulfonatosalicylidene)-diaminoethane (H2salen-SO3), will readily coordinate to the uranyl(vi) cation, but not to the same extent to trivalent lanthanide cations. This allows for the reversal of conventional solvent extraction properties and opens the possibility for novel separation processes. PMID:24958394

Hawkins, C A; Bustillos, C G; Copping, R; Scott, B L; May, I; Nilsson, M

2014-08-14

206

The strong, weak and anomalous sides of weak topological insulators  

NASA Astrophysics Data System (ADS)

Disorder and topology can be thought of as two counter-driving forces. While the former pushes electron wave functions to localize in space, the latter requires them to remain coherent over the entire system. We study the interplay between these two on the surface of a ``weakly'' topological phase- the Weak Topological Insulator. Using arguments based on flux-insertions and locality, we show that such surfaces cannot undergo a localization transition even when the surface is strongly disordered. We also present a numerical study which further quantifies this result. We then reformulate the same notions, in field theory language, using a novel Z2-charge-anomaly. This anomaly generalizes the Z-charge-anomaly associated with edges of the Integer Quantum Hall Effect. Besides unifying various aspects of Topological Insulators, the anomaly allows us to calculate new topological properties of TIs in the presence of electric fields.

Ringel, Zohar

2013-03-01

207

Competing weak localization and weak antilocalization in ultrathin topological insulators.  

PubMed

We demonstrate evidence of a surface gap opening in topological insulator (TI) thin films of (Bi(0.57)Sb(0.43))(2)Te(3) below six quintuple layers through transport and scanning tunneling spectroscopy measurements. By effective tuning the Fermi level via gate-voltage control, we unveil a striking competition between weak localization and weak antilocalization at low magnetic fields in nonmagnetic ultrathin films, possibly owing to the change of the net Berry phase. Furthermore, when the Fermi level is swept into the surface gap of ultrathin samples, the overall unitary behaviors are revealed at higher magnetic fields, which are in contrast to the pure WAL signals obtained in thicker films. Our findings show an exotic phenomenon characterizing the gapped TI surface states and point to the future realization of quantum spin Hall effect and dissipationless TI-based applications. PMID:23198980

Lang, Murong; He, Liang; Kou, Xufeng; Upadhyaya, Pramey; Fan, Yabin; Chu, Hao; Jiang, Ying; Bardarson, Jens H; Jiang, Wanjun; Choi, Eun Sang; Wang, Yong; Yeh, Nai-Chang; Moore, Joel; Wang, Kang L

2013-01-01

208

Plant Breeding Coordinating Committee  

NSDL National Science Digital Library

 To view additional success stories click on the link in the left menu Please click here to report your plant breeding success stories.  Click on TCAP logo to see the Economic impact of USDA-NIFA small grains CAPsThe Plant Breeding Coordinating Committee (SCC 080) is the USDA-sponsored advisory group of representatives from land grant universities.  The Plant Breeding Coordinating Committee represents national plant breeding with a focus on education in the broader sense, including providing information to the public and administrators, and encouraging the development of formal educational opportunities, continuing education, and lifelong learning. Mission: To provide a forum for leadership on issues and opportunities of strategic importance to national core competency in plant breeding research and education Membership: The PBCC members will consist of the representatives of the SCC-080 committee and others by request. 

209

Redesign standardizes care coordination.  

PubMed

By centralizing administrative and clerical tasks usually performed by clinical staff, the care coordination department at Sentara Healthcare, with headquarters in Norfolk, VA, has freed the bedside staff to concentrate on case management and discharge planning. RN care coordinators and master's prepared social workers collaborate to manage care on the unit, holding a daily huddle and participating in multidisciplinary rounds. Clerical staff set post-discharge appointments with primary care providers while the patient is still in the hospital. Staff members at a centralized Resource Management Center, created at a new location, are responsible for utilization management, including admissions reviews, continuing stay reviews, and retrospective reviews and facilitation of discharges for patients in all hospitals. PMID:22639768

2012-06-01

210

Link between protein-solvent and weak protein-protein interactions gives insight into halophilic adaptation.  

PubMed

Malate dehydrogenase (Hm MalDH) from the extreme halophile Haloarcula marismortui is a very acidic protein with extensive ion binding properties. It is a good model for the study of solvation-solubility relationships. We measured the small-angle neutron or X-ray scattering profiles of folded and stable Hm MalDH at various protein concentrations and derived the second virial coefficients A(2). In NaCl, CsCl, KF, KCl, and NaCH(3)CO(2), A(2) values are positive, indicating globally repulsive protein-protein interactions. Below 1 M MgCl(2) and MgSO(4) or above 2 M (NH(4))(2)SO(4), A(2) rapidly decreases. From structure factor modeling with DLVO (Derjaguin, Landau, Verwey, and Overbeek)-like potentials, an effective diameter of 80-82 A is found for the protein particle in solution, compatible with its structural dimensions; the effective charge of the particle is undefined because of the high salt concentration. The strong variations of the protein-protein interaction are correlated to an attractive potential whose depth evolves with the salinity but in an opposite way in Mg salts and (NH(4))(2)SO(4). A repulsive Donnan term, corresponding to counterion dissociation, and an attractive term related to previously measured preferential salt binding parameters are discussed from well-established thermodynamics considerations and qualitatively account for the behavior of the protein-protein interactions in the various solutions. Because a solvation shell with a composition different from bulk induces protein-protein attraction, molecular adaptation to high salt would be directed to allow protein-salt interactions in order to avoid water or salt enrichment at the surface of the protein and thus preserve its solubility. PMID:12403626

Costenaro, Lionel; Zaccai, Giuseppe; Ebel, Christine

2002-11-01

211

Enzyme flexibility, solvent and ‘weak’ interactions characterize thrombin–ligand interactions: implications for drug design  

Microsoft Academic Search

Background The explosive growth in the rate of X-ray determination of protein structures is fuelled largely by the expectation that structural information will be useful for pharmacological and biotechnological applications. For example, there have been intensive efforts to develop orally administrable antithrombotic drugs using information about the crystal structures of blood coagulation factors, including thrombin. Most of the low molecular

Richard A Engh; Hans Brandstetter; Gudrun Sucher; Andreas Eichinger; Ulrich Baumann; Wolfram Bode; Robert Huber; Thomas Poll; Rainer Rudolph; Wolfgang von der Saal

1996-01-01

212

Photoswitchable coordination compounds  

Microsoft Academic Search

Photoswitchable compounds represent an attractive class of materials in coordination chemistry. Recent progress dealing with transition metal compounds involving photo-induced changes of the magnetic and\\/or optical properties to long-lived metastable states are covered in the present review article. The basic photophysical phenomena together with representative examples such as nitroprusside derivatives, relevant spin crossover complexes, stilbenoid complexes and finally Prussian blue

Philipp Gütlich; Yann Garcia; Theo Woike

2001-01-01

213

Coordination in inorganics  

Microsoft Academic Search

Coordination number (CN) is discussed from a geometrical point of view. Two models for the determination of CN 8 to 11 have\\u000a been developed and tested with good results on 78 polyhedra consisting of alkali\\/alkaline earth metals as central atoms and\\u000a halogen atoms\\/water oxygens as ligands. In these models the polyhedral volume (Volpoly), the volume of a sphere — least-squares

R. Sjövall; S. Lidin

214

Weak values and weak coupling maximizing the output of weak measurements  

NASA Astrophysics Data System (ADS)

In a weak measurement, the average output of a probe that measures an observable Aˆ of a quantum system undergoing both a preparation in a state ? and a postselection in a state E is, to a good approximation, a function of the weak value Aw=Tr[EAˆ?]/Tr[E?], a complex number. For a fixed coupling ?, when the overlap Tr[E?] is very small, Aw diverges, but stays finite, often tending to zero for symmetry reasons. This paper answers the questions: what is the weak value that maximizes the output for a fixed coupling? What is the coupling that maximizes the output for a fixed weak value? We derive equations for the optimal values of Aw and ?, and provide the solutions. The results are independent of the dimensionality of the system, and they apply to a probe having a Hilbert space of arbitrary dimension. Using the Schrödinger-Robertson uncertainty relation, we demonstrate that, in an important case, the amplification cannot exceed the initial uncertainty ?o in the observable oˆ, we provide an upper limit for the more general case, and a strategy to obtain ??o.

Di Lorenzo, Antonio

2014-06-01

215

Occupational exposure to organic solvents and breast cancer in women  

PubMed Central

Background Although studies in rodents suggest possible associations between exposure to organic solvents and breast cancer, the evidence in humans is limited. Methods We evaluated job histories of 2383 incident breast cancer cases diagnosed during 2000–2003, and 2502 controls who participated in a large population-based case-control study in Poland. Industrial hygienists reviewed occupational histories and developed exposure metrics for total organic solvents and benzene. Unconditional logistic regression analyses estimated odds ratios (ORs) and 95% confidence intervals (CIs) as the measure of association with breast cancer, controlling for breast cancer risk factors. Stratified analyses examined the potential modification by known breast cancer risk factors. Associations were also evaluated by estrogen (ER) and progesterone receptor (PR) status and by other clinical characteristics of the tumours using polytomous regression analyses. Results Women who ever worked at jobs with organic solvents exposure had a small, non-significant increase in breast cancer risk (OR=1.16; 95%CI 0.99 to 1.4). A significant association was present for ER and PR negative tumors (OR 1.40; 95% CI 1.1 to 1.8), but there was no association with tumors with both positive receptors (OR 0.97; 95% CI 0.8 to 1.2 (p-heterogeneity: 0.008)). We did not observe trends with increasing level of exposure. Known breast cancer risk factors did not modify the association with organic solvents and breast cancer risk. No association with breast cancer was found for benzene exposure (OR 1.00; 95% CI 0.8 to 1.3). Conclusion Our study provides weak evidence for a possible association between occupational exposure to organic solvents as a class and breast cancer risk. The association might be limited to hormone receptor negative tumors.

Peplonska, Beata; Stewart, Patricia; Szeszenia-Dabrowska, Neonila; Lissowska, Jolanta; Brinton, Louise A.; Gromiec, Jan Piotr; Brzeznicki, Slawomir; Yang, Rose; Sherman, Mark; Garcia-Closas, Montserrat; Blair, Aaron

2009-01-01

216

Cold-spray ionization mass spectrometric detection of a coordination oligomer.  

PubMed

Coordination polymer (CP) formation is an unexplored area in weak-interaction chemistry due to the difficulty of monitoring the coordination process. By using cold-spray ionization mass spectrometry (CSI-MS), several kinds of coordination compounds were detected when CuI metal and the 4,7-phenanthroline organic bridged ligand were mixed in solution. The observed ion peaks could be reasonably and simply assigned to various combinations of the metal and the ligand without any fragmentation. PMID:22790362

Ohara, Kazuaki; Yamaguchi, Kentaro

2012-01-01

217

Weak Coupling in 143Nd  

NASA Astrophysics Data System (ADS)

The high-spin states of 143Nd have been studied in the 130Te(18O, 5n)143Nd reaction at a beam energy of 80 MeV using techniques of in-beam ?-ray spectroscopy. Measurements of ? - ? - t coincidences, ?-ray angular distributions, and ?-ray linear polarizations were performed. A level scheme of 143Nd with spin and parity assignments up to 53/2+ is proposed. While a weak coupling model can explain the level structure up to the J?=39/2- state, this model can not reproduce the higher-lying states. Additionally, a new low-lying non-yrast level sequence in 143Nd was observed in the present work, which can be well described by the weak coupling of an i13/2 neutron to the 142Nd core nucleus.

Zhou, Xiao-Hong; E, Ideguchi; T, Kishida; M, Ishihara; H, Tsuchida; Y, Gono; T, Morikawa; M, Shibata; H, Watanabe; M, Miyake; T, Tsutsumi; S, Motomura; S, Mitarai

2000-04-01

218

Explosive shielding by weak layers  

SciTech Connect

This paper presents the results of a series of computations which were carried out to determine the effect that a layer of extremely weak rock embedded in an otherwise strong rock matrix would have on the displacements and velocities which result from the detonation of a nearby explosive source. The motivation for the study was the apparently different measurements obtained on the Mission Cyber Nuclear Event when compared to results obtained from other events of equal yield in similar geologic media.

Fourney, W.L.; Dick, R.D.; Weaver, T.A.

1993-01-01

219

Explosive shielding by weak layers  

SciTech Connect

This paper presents the results of a series of computations which were carried out to determine the effect that a layer of extremely weak rock embedded in an otherwise strong rock matrix would have on the displacements and velocities which result from the detonation of a nearby explosive source. The motivation for the study was the apparently different measurements obtained on the Mission Cyber Nuclear Event when compared to results obtained from other events of equal yield in similar geologic media.

Fourney, W.L.; Dick, R.D.; Weaver, T.A.

1993-02-01

220

Quark mixing in weak interactions  

Microsoft Academic Search

The status of the quark mixing in weak interaction is reviewed. The 3×3 quark mixing matrix for the three left-handed doublet model is analyzed using various experimental information involving strange, charmed, and b-flavored particles. Its interplay with nonleptonic decays, implication on neutral particle-antiparticle mixing and CP violation in heavy quark systems, and the possible origin of the quark mixing from

Ling-Lie Chau

1983-01-01

221

Compatibility of Contaminants and Plastics with Solvents.  

National Technical Information Service (NTIS)

The use of solvents is being examined as a result of environmental improvement requirements being established by state and federal agencies. Although purchase cost is a factor in selecting alternate solvents for particular requirements, performance contro...

L. C. Jackson E. T. Walsh

1975-01-01

222

Dipolar correlations in structured solvents under nanoconfinement.  

PubMed

We study electrostatic correlations in structured solvents confined to nanoscale systems. We derive variational equations of Netz-Orland type for a model liquid composed of finite size dipoles. These equations are solved for both dilute solvents and solvents at physiological concentrations in a slit nanopore geometry. Correlation effects are of major importance for the dielectric reduction and anisotropy of the solvent resulting from dipole image interactions and also lead to a reduction of van der Waals attractions between low dielectric bodies. Finally, by comparison with other recently developed self-consistent theories and experiments, we scrutinize the effect of solvent-membrane interactions on the differential capacitance of the charged liquid in contact with low dielectric substrates. The interfacial solvent depletion driven by solvent-image interactions plays the major role in the observed low values of the experimental capacitance data, while non-locality associated with the extended charge structure of solvent molecules only brings a minor contribution. PMID:24952564

Buyukdagli, Sahin; Blossey, Ralf

2014-06-21

223

Alternatives to Solvent-Borne Adhesives.  

National Technical Information Service (NTIS)

Rapidly escalating costs of solvent borne adhesives have now given water borne adhesives a significant economic advantage to further advance the environmental and OSHA forces already acting to reduce solvent usage. Water borne adhesive systems based on ch...

W. C. Kania

1980-01-01

224

Dipolar correlations in structured solvents under nanoconfinement  

NASA Astrophysics Data System (ADS)

We study electrostatic correlations in structured solvents confined to nanoscale systems. We derive variational equations of Netz-Orland type for a model liquid composed of finite size dipoles. These equations are solved for both dilute solvents and solvents at physiological concentrations in a slit nanopore geometry. Correlation effects are of major importance for the dielectric reduction and anisotropy of the solvent resulting from dipole image interactions and also lead to a reduction of van der Waals attractions between low dielectric bodies. Finally, by comparison with other recently developed self-consistent theories and experiments, we scrutinize the effect of solvent-membrane interactions on the differential capacitance of the charged liquid in contact with low dielectric substrates. The interfacial solvent depletion driven by solvent-image interactions plays the major role in the observed low values of the experimental capacitance data, while non-locality associated with the extended charge structure of solvent molecules only brings a minor contribution.

Buyukdagli, Sahin; Blossey, Ralf

2014-06-01

225

Wash solvent reuse in paint production  

SciTech Connect

The project evaluated solvent used to clean paint manufacture equipment for its utility in production of subsequent batches of solvent-borne paint. Reusing wash solvent would reduce the amount of solvent disposed of as waste. The evaluation of this wash-solvent recovery technology was conducted by Battelle Memorial Institute for the Pollution Prevention Research Branch of the U.S. Environmental Protection Agency. The evaluation was conducted with the cooperation and assistance of Vanex Color, Inc. The product quality, waste reduction/pollution prevention, and economic impacts of this technology change, as it has been implemented by Vanex, were examined. Two batches of a solvent-borne alkyd house paint were prepared at Vanex--one batch made with 100%-new solvent and the other with 30%-wash solvent--and sampled for laboratory analysis at Battelle.

Parsons, A.B.; Heater, K.J.; Olfenbuttel, R.F.

1994-04-01

226

Restoring Solvent for Nuclear Separation Processes.  

National Technical Information Service (NTIS)

Solvent extraction separation processes are used to recover usable nuclear materials from spent fuels. These processes involve the use of an extractant/diluent (solvent) for separation of the reusable actinides from unwanted fission products. The most wid...

D. J. Reif

1987-01-01

227

Solvent refining of Kuwaiti heavy diesel oil  

SciTech Connect

Results of studies to determine the optimum operating conditions for the solvent refining of Kuwaiti heavy diesel oil (HDO) to find the most suitable solvent for the production of lube oil base stocks from HDO are reported. The solvents studied were furfural, ..beta..-methoxypropionitrile (..beta..-MPN) and N-methylpyrrolidone (NMP). NMP was found to have the highest capacity as a solvent. (BLM)

Ijam, M.J.; Fahim, M.A.; Abu-Elgheit, M.

1981-08-01

228

Preparation of coal slurry with organic solvents  

Microsoft Academic Search

In this study, various organic solvents were used to prepare coal slurries and the rheological and thermal properties of coal–organic solvent slurries were examined. Solvents with molecules containing unpaired electrons (high basicity) show high extraction power and cause swelling of coal. Therefore, coal–organic solvent slurries usually showed higher viscosities compared to coal–water slurry. In addition, coal slurries prepared by alcohols

Yu-Jen Shin; Yun-Hwei Shen

2007-01-01

229

Dynamic self-assembly of coordination polymers in aqueous solution.  

PubMed

The construction of supramolecular polymers has been intensively pursued because the nanostructures formed through weak non-covalent interactions can be triggered by external stimuli leading to smart materials and sensors. Self-assemblies of coordination polymers consisting of metal ions and organic ligands in aqueous solution also provide particular contributions in this area. The main motivation for developing those coordination polymers originates from the value-added combination between metal ions and ligands. This review highlights the recent progress of the dynamic self-assembly of coordination polymers that result from the sophisticated molecular design, towards fabricating stimuli-responsive systems and bio-related materials. Dynamic structural changes and switchable physical properties triggered by various stimuli are summarized. Finally, the outlook for aqueous nanostructures originated from the dynamic self-assembly of coordination polymers is also presented. PMID:24955807

Li, Wen; Kim, Yongju; Li, Jingfang; Lee, Myongsoo

2014-08-01

230

Effect of organic solvents on particle size of Mn3O4 nanoparticles synthesized by a solvothermal method  

NASA Astrophysics Data System (ADS)

In this paper, a modified simple solvothermal method is employed to synthesize Mn3O4 nanocrystals using four different solvents: acetone, ethanol, N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO). Mn3O4 nanoparticles with a tetragonal hausmannite nano-structure are characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), as well as superconducting quantum interference device magnetometer (SQUID). The Mn3O4 particle size is found to have a strong dependency on the solvent used. A reaction scheme is proposed to understand this dependency, suggesting that the solvent coordinating capability has a critical effect on Mn3O4 particle size. The stronger the coordinating capability of the solvent is, the smaller the Mn3O4 particle size is. In addition, magnetic properties of the nano-structured Mn3O4 are also tested and discussed.

Song, Rui; Feng, Shouhua; Wang, Hongjun; Hou, Changmin

2013-06-01

231

Service Coordination: The School Counselor.  

ERIC Educational Resources Information Center

Discusses how counselors can successfully execute the responsibilities of a service coordinator to enhance counseling effectiveness. Describes three phases of service coordination: information retrieval, information assessment, and information administration. (RC)

DeVoe, Marianne W.; McClam, Tricia

1982-01-01

232

Work Coordination Engine  

NASA Technical Reports Server (NTRS)

The Work Coordination Engine (WCE) is a Java application integrated into the Service Management Database (SMDB), which coordinates the dispatching and monitoring of a work order system. WCE de-queues work orders from SMDB and orchestrates the dispatching of work to a registered set of software worker applications distributed over a set of local, or remote, heterogeneous computing systems. WCE monitors the execution of work orders once dispatched, and accepts the results of the work order by storing to the SMDB persistent store. The software leverages the use of a relational database, Java Messaging System (JMS), and Web Services using Simple Object Access Protocol (SOAP) technologies to implement an efficient work-order dispatching mechanism capable of coordinating the work of multiple computer servers on various platforms working concurrently on different, or similar, types of data or algorithmic processing. Existing (legacy) applications can be wrapped with a proxy object so that no changes to the application are needed to make them available for integration into the work order system as "workers." WCE automatically reschedules work orders that fail to be executed by one server to a different server if available. From initiation to completion, the system manages the execution state of work orders and workers via a well-defined set of events, states, and actions. It allows for configurable work-order execution timeouts by work-order type. This innovation eliminates a current processing bottleneck by providing a highly scalable, distributed work-order system used to quickly generate products needed by the Deep Space Network (DSN) to support space flight operations. WCE is driven by asynchronous messages delivered via JMS indicating the availability of new work or workers. It runs completely unattended in support of the lights-out operations concept in the DSN.

Zendejas, Silvino; Bui, Tung; Bui, Bach; Malhotra, Shantanu; Chen, Fannie; Kim, Rachel; Allen, Christopher; Luong, Ivy; Chang, George; Sadaqathulla, Syed

2009-01-01

233

Solid-state reactivity and structural transformations involving coordination polymers.  

PubMed

This tutorial review discusses recent literature on coordination polymers and metal-organic frameworks (MOFs) that exhibit solid-state reactivity and structural transformation under various experimental conditions. Removal or exchange of solvents and guest molecules, exposure to reactive vapours, and external stimuli such as heat, light or mechanochemical force cause such structural transformations and these are often manifested by various physical properties such as colour, magnetism, luminescence, chirality, porosity, etc. due to change in coordination number and geometry, dimensionality, interpenetration, etc. More drastic transformations related to the exchange of metal ions, pillar ligands and insertion of additional ligands between the layers have also been demonstrated. The vast area of dynamic behaviour of coordination polymers and their stimuli-responsive properties have also been addressed briefly. PMID:23034597

Kole, Goutam Kumar; Vittal, Jagadese J

2013-02-21

234

Restoring solvent for nuclear separation processes  

Microsoft Academic Search

Solvent extraction separation processes are used to recover usable nuclear materials from spent fuels. These processes involve the use of an extractant\\/diluent (solvent) for separation of the reusable actinides from unwanted fission products. The most widely used processes employ tributyl phosphate as an extractant diluted with a normal-paraffin hydrocarbon. During use, the solvent is altered due to hydrolysis and radiolysis,

Rief

1988-01-01

235

Restoring solvent for nuclear separation processes  

Microsoft Academic Search

Solvent extraction separation processes are used to recover usable nuclear materials from spent fuels. These processes involve the use of an extractant\\/diluent (solvent) for separation of the reusable actinides from unwanted fission products. The most widely used processes employ tributyl phosphate as an extractant diluted with a normal-paraffin hydrocarbon. During use, the solvent is altered due to hydrolysis and radiolysis,

Reif

1987-01-01

236

Restoring Solvent for Nuclear Separation Processes  

Microsoft Academic Search

Solvent extraction separation processes are used to recover usable nuclear materials from spent fuels. These processes involve the use of an extractant\\/diluent (solvent) for separation of the reusable actinides from unwanted fission products. The most widely used processes employ tributyl phosphate as an extractant diluted with a normal-paraffin hydrocarbon. During use, the solvent is altered due to hydrolysis and radiolysis,

D. J. Reif

1988-01-01

237

The use of alternative solvent purification techniques  

Microsoft Academic Search

A recent accident at the University of California, Irvine involved the purification of an organic solvent using a solvent still resulting in a fire in the lab. A graduate student was seriously burned and $3.5 million in property damage was incurred. In this report, lessons learned from this accident are used to improve the safety of solvent purification operations. Column

Michael E. Cournoyer; Jeffrey H Dare

2003-01-01

238

Solvent Extraction of Furfural From Biomass  

NASA Technical Reports Server (NTRS)

Solvent-extraction method reduces energy required to remove furfural produced during acid hydrolysis of biomass. Acid hydrolysis performed in vessel containing both solvents and reacting ingredients. With intimate contact between solvents and aqueous hydrolyis liqour, furfural removed form liquor almost as fast as it forms.

Humphrey, M. F.

1984-01-01

239

Firing of pulverized solvent refined coal  

DOEpatents

An air-purged burner for the firing of pulverized solvent refined coal is constructed and operated such that the solvent refined coal can be fired without the coking thereof on the burner components. The air-purged burner is designed for the firing of pulverized solvent refined coal in a tangentially fired boiler.

Derbidge, T. Craig (Sunnyvale, CA); Mulholland, James A. (Chapel Hill, NC); Foster, Edward P. (Macungie, PA)

1986-01-01

240

Solvent characterization using the dispersion number.  

National Technical Information Service (NTIS)

When developing new solvent extraction processes, one often has to evaluate new solvents, new aqueous phases, or both for their ability to work in plant-scale equipment. To facilitate solvent characterization, a simple test is proposed based on the dimens...

R. A. Leonard

1993-01-01

241

Solvent-free oil dispersant  

US Patent & Trademark Office Database

The present invention is directed toward an oil dispersant composition useful in treating oil spills, and for cleanup of the shoreline, animals, plants, and equipment. The oil dispersant product is a non-toxic, solvent-free composition which efficiently breaks down grease, grime and crude oil at the molecular level, by breaking down the hydrocarbon chains and preventing the oil molecules from ever reforming again.

2013-04-09

242

EMS Course Coordinator's Implementation Guide.  

ERIC Educational Resources Information Center

This handbook is intended to clarify the responsibilities of an instructor-coordinator responsible for coordinating an emergency medical services (EMS) training program and to describe many of the materials now available for use in coordinating EMS training. Addressed in the individual chapters of the guide are the nature and scope of the…

Cockrum, Jim

243

COCA: collaborative objects coordination architecture  

Microsoft Academic Search

Coordination policies vary from collaboration to collaboration and are even subject to evolution in different phases of the same collaboration. It is vital for collaborative systems to be flexible enough to accommodate changes to the coordination policies during development and the lifetime of the collaboration. Motivated by previous work of separating coordination and computation, we propose COCA as a generic

Du Li; Richard R. Muntz

1998-01-01

244

Child labor and coordination failures  

Microsoft Academic Search

In this note, we show that a technology-based coordination failure may explain the emergence of laws restricting child labor. Child labor may arise because of the lack of a coordination mechanism between parental decisions to invest in the human capital of their children and firms' decisions to invest in skill-biased technologies. Legislative intervention in many cases helps coordinate expectations towards

Sylvain E. Dessy; Stéphane Pallage

2001-01-01

245

Network Coordinates in the Wild  

Microsoft Academic Search

Network coordinates provide a mechanism for select- ing and placing servers efficiently in a large distributed system. This approach works well as long as the coordi- nates continue to accurately reflect network topology. We conducted a long-term study of a subset of a million-plus node coordinate system and found that it exhibited some of the problems for which network coordinates

Jonathan Ledlie; Paul Gardner; Margo I. Seltzer

2007-01-01

246

Solvent cleaning system and method for removing contaminants from solvent used in resin recycling  

DOEpatents

A two step solvent and carbon dioxide based system that produces essentially contaminant-free synthetic resin material and which further includes a solvent cleaning system for periodically removing the contaminants from the solvent so that the solvent can be reused and the contaminants can be collected and safely discarded in an environmentally safe manner.

Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee's Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

2009-01-06

247

Cleanup of 7. 5% tributyl phosphate\\/n-paraffin solvent-extraction solvent  

Microsoft Academic Search

The HM process at the Savannah River Plant uses 7.5% tributyl phosphate in n-paraffin as an extraction solvent. During use, the solvent is altered due to hydrolysis and radiolysis, forming materials which influence product losses, product decontamination, and separation efficiencies. Laboratory studies to improve online solvent cleaning have shown that carbonate washing, although removing residual solvent activity, does not remove

Reif

1987-01-01

248

SOLVENT DISPERSION AND FLOW METER CALCULATION RESULTS  

SciTech Connect

Savannah River National Laboratory (SRNL) found that the dispersion numbers for the six combinations of CSSX:Next Generation Solvent (NGS) “blend” and pure NGS versus salt solution, caustic wash, and strip aqueous solutions are all good. The dispersion numbers are indications of processability with centrifugal contactors. A comparison of solvent physical and thermal properties shows that the Intek™ solvent flow meter in the plant has a reading biased high versus calibrated flow when NGS is used, versus the standard CSSX solvent. The flow meter, calibrated for CSSX solvent, is predicted to read 2.8 gpm of NGS in a case where the true flow of NGS is 2.16 gpm.

Nash, C.; Fondeur, F.; Peters, T.

2013-06-21

249

Aminosilicone solvents for CO(2) capture.  

PubMed

This work describes the first report of the use of an aminosilicone solvent mix for the capture of CO(2). To maintain a liquid state, a hydroxyether co-solvent was employed which allowed enhanced physisorption of CO(2) in the solvent mixture. Regeneration of the capture solvent system was demonstrated over 6 cycles and absorption isotherms indicate a 25-50 % increase in dynamic CO(2) capacity over 30 % MEA. In addition, proof of concept for continuous CO(2) absorption was verified. Additionally, modeling to predict heats of reaction of aminosilicone solvents with CO(2) was in good agreement with experimental results. PMID:20730981

Perry, Robert J; Grocela-Rocha, Teresa A; O'Brien, Michael J; Genovese, Sarah; Wood, Benjamin R; Lewis, Larry N; Lam, Hubert; Soloveichik, Grigorii; Rubinsztajn, Malgorzata; Kniajanski, Sergei; Draper, Sam; Enick, Robert M; Johnson, J Karl; Xie, Hong-bin; Tapriyal, Deepak

2010-08-23

250

Staggered weak matrix element miscellany  

NASA Astrophysics Data System (ADS)

I report on work, done with Rajan Gupta and Greg Kilcup, using staggered fermions to study weak matrix elements in quenched QCD. I give an update on the ?I = {1}/{2} rule and on matrix elements and relevant for ?'. I show results of a study of the dependence of BK on non-leading terms in the chiral expansion. I present our first results for BK from a quenched calculation at ß = 6.4 on 32 3 × 48 lattices, based o n an ensemble of 12 configurations.

Sharpe, Stephen R.

1991-05-01

251

Variation and decomposition of the partial molar volume of small gas molecules in different organic solvents derived from molecular dynamics simulations  

NASA Astrophysics Data System (ADS)

The partial molar volumes, bar V_i, of the gas solutes H2, CO, and CO2, solvated in acetone, methanol, heptane, and diethylether are determined computationally in the limit of infinite dilution and standard conditions. Solutions are described with molecular dynamics simulations in combination with the OPLS-aa force field for solvents and customized force field for solutes. bar V_i is determined with the direct method, while the composition of bar V_i is studied with Kirkwood-Buff integrals (KBIs). Subsequently, the amount of unoccupied space and size of pre-formed cavities in pure solvents is determined. Additionally, the shape of individual solvent cages is analyzed. Calculated bar V_i deviate only 3.4 cm3 mol-1 (7.1%) from experimental literature values. Experimental bar V_i variations across solutions are reproduced qualitatively and also quantitatively in most cases. The KBI analysis identifies differences in solute induced solvent reorganization in the immediate vicinity of H2 (<0.7 nm) and solvent reorganization up to the third solvation shell of CO and CO2 (<1.6 nm) as the origin of bar V_i variations. In all solutions, larger bar V_i are found in solvents that exhibit weak internal interactions, low cohesive energy density and large compressibility. Weak internal interactions facilitate solvent displacement by thermal solute movement, which enhances the size of solvent cages and thus bar V_i. Additionally, attractive electrostatic interactions of CO2 and the solvents, which do not depend on internal solvent interactions only, partially reversed the bar V_i trends observed in H2 and CO solutions where electrostatic interactions with the solvents are absent. More empty space and larger pre-formed cavities are found in solvents with weak internal interactions, however, no evidence is found that solutes in any considered solvent are accommodated in pre-formed cavities. Individual solvent cages are found to be elongated in the negative direction of solute movement. This wake behind the moving solute is more pronounced in case of mobile H2 and in solvents with weaker internal interactions. However, deviations from a spherical solvent cage shape do not influence solute-solvent radial distribution functions after averaging over all solvent cage orientations and hence do not change bar V_i. Overall, the applied methodology reproduces bar V_i and its variations reliably and the used bar V_i decompositions identify the underlying reasons behind observed bar V_i variations.

Klähn, Marco; Martin, Alistair; Cheong, Daniel W.; Garland, Marc V.

2013-12-01

252

Effect of solvents on obligately anaerobic bacteria.  

PubMed

Growth of Acetobacterium woodii and Clostridium sporogenes was studied in the presence of water-immiscible solvents. Nitrogen purging, vacuum distillation or distillation under nitrogen were all suitable as methods to remove oxygen from the solvents, since growth rates and yields of A. woodii were unaffected in the presence of tetradecane which had been degassed by these methods. Varying the solvent volume from 20% to 80% of the culture volume had little effect on growth rate of A. woodii. A.woodii was relatively sensitive to organic solvents since growth was inhibited by alkanes with logP(octanol/water) values below 7.1. C. sporogenes was less solvent sensitive, since it grew without inhibition when the logP of the solvent was > or = 6.6. Nevertheless, both A. woodii and C. sporogenes were more sensitive to solvent polarity than aerobic bacteria. PMID:18083050

Rodriguez Martinez, Maria Fernanda; Kelessidou, Niki; Law, Zoe; Gardiner, John; Stephens, Gill

2008-02-01

253

Price schedules coordination for electricity pool markets  

NASA Astrophysics Data System (ADS)

We consider the optimal coordination of a class of mathematical programs with equilibrium constraints, which is formally interpreted as a resource-allocation problem. Many decomposition techniques were proposed to circumvent the difficulty of solving large systems with limited computer resources. The considerable improvement in computer architecture has allowed the solution of large-scale problems with increasing speed. Consequently, interest in decomposition techniques has waned. Nonetheless, there is an important class of applications for which decomposition techniques will still be relevant, among others, distributed systems---the Internet, perhaps, being the most conspicuous example---and competitive economic systems. Conceptually, a competitive economic system is a collection of agents that have similar or different objectives while sharing the same system resources. In theory, constructing a large-scale mathematical program and solving it centrally, using currently available computing power can optimize such systems of agents. In practice, however, because agents are self-interested and not willing to reveal some sensitive corporate data, one cannot solve these kinds of coordination problems by simply maximizing the sum of agent's objective functions with respect to their constraints. An iterative price decomposition or Lagrangian dual method is considered best suited because it can operate with limited information. A price-directed strategy, however, can only work successfully when coordinating or equilibrium prices exist, which is not generally the case when a weak duality is unavoidable. Showing when such prices exist and how to compute them is the main subject of this thesis. Among our results, we show that, if the Lagrangian function of a primal program is additively separable, price schedules coordination may be attained. The prices are Lagrange multipliers, and are also the decision variables of a dual program. In addition, we propose a new form of augmented or nonlinear pricing, which is an example of the use of penalty functions in mathematical programming. Applications are drawn from mathematical programming problems of the form arising in electric power system scheduling under competition.

Legbedji, Alexis Motto

2002-04-01

254

IR linear dichroic study of high-symmetry molecules dissolved in a liquid crystal solvent. II. Metal hexacarbonyl complexes M(CO) 6 (M = Mo, Cr)  

NASA Astrophysics Data System (ADS)

The presence of weak specific solvent—solute interactions is proved by studying the splitting of the ? 3(F 1u) band of M(CO) 6 (M = Mo, Cr) in some isotropic electron donor solvents. A similar spectral effect is observed in the smectic, nematic and isotropic phases of the liquid crystal ZLI 1167 (Merck) and is explained by similar interactions. The complex (bisignate) shape of the IR-LD spectra of M(CO) 6 in the anisotropic solvent is considered to be a manifestation of the same solvent effect.

Rogojerov, Marin I.; Arnaudov, Michail G.

1994-05-01

255

Weak lensing and cosmological investigation  

NASA Astrophysics Data System (ADS)

In the last few years the scientific community has been dealing with the challenging issue of identifying the dark energy component. We regard weak gravitational lensing as a brand new, and extremely important, tool for cosmological investigation in this field. In fact, the features imprinted on the Cosmic Microwave Background radiation by the lensing from the intervening distribution of matter represent a pretty unbiased estimator, and can thus be used for putting constraints on different dark energy models. This is true in particular for the magnetic-type B-modes of CMB polarization, whose unlensed spectrum at large multipoles (l ~= 1000) is very small even in presence of an amount of gravitational waves as large as currently allowed by the experiments: therefore, on these scales the lensing phenomenon is the only responsible for the observed power, and this signal turns out to be a faithful tracer of the dark energy dynamics. We first recall the formal apparatus of the weak lensing in extended theories of gravity, introducing the physical observables suitable to cast the bridge between lensing and cosmology, and then evaluate the amplitude of the expected effect in the particular case of a Non-Minimally-Coupled model, featuring a quadratic coupling between quintessence and Ricci scalar.

Acquaviva, Viviana

2005-03-01

256

Weak Lensing with Galaxy Kinematics  

NASA Astrophysics Data System (ADS)

Weak lensing is weak because the shear signal is much smaller than the noise set by the broad distribution of intrinsic galaxy shapes. We describe a technique that can reduce shape noise by an order of magnitude using spatially-resolved spectroscopy to derive kinematic maps of source galaxies. Shear oriented along the principle axes of a rotating disk induces an offset from the Tully-Fisher relation after inclination corrections, while shear applied at an angle to the disk skews the kinematic axes relative to the photometric axes. Existing multi-object optical spectrographs and IFUs have the spatial and spectral resolution to measure this effect at high signal-to-noise. We discuss science applications ranging from high resolution cluster mass mapping to cosmic shear, including the statistical and systematic uncertainties which can be competitive with and complementary to traditional shear surveys. Notably, the need for photometric redshifts is eliminated, while biases due to shear calibration and intrinsic alignments can be significantly reduced.

George, Matthew R.; Huff, E. M.; Schlegel, D. J.

2014-01-01

257

Weakly Circadian Cells Improve Resynchrony  

PubMed Central

The mammalian suprachiasmatic nuclei (SCN) contain thousands of neurons capable of generating near 24-h rhythms. When isolated from their network, SCN neurons exhibit a range of oscillatory phenotypes: sustained or damping oscillations, or arrhythmic patterns. The implications of this variability are unknown. Experimentally, we found that cells within SCN explants recover from pharmacologically-induced desynchrony by re-establishing rhythmicity and synchrony in waves, independent of their intrinsic circadian period We therefore hypothesized that a cell's location within the network may also critically determine its resynchronization. To test this, we employed a deterministic, mechanistic model of circadian oscillators where we could independently control cell-intrinsic and network-connectivity parameters. We found that small changes in key parameters produced the full range of oscillatory phenotypes seen in biological cells, including similar distributions of period, amplitude and ability to cycle. The model also predicted that weaker oscillators could adjust their phase more readily than stronger oscillators. Using these model cells we explored potential biological consequences of their number and placement within the network. We found that the population synchronized to a higher degree when weak oscillators were at highly connected nodes within the network. A mathematically independent phase-amplitude model reproduced these findings. Thus, small differences in cell-intrinsic parameters contribute to large changes in the oscillatory ability of a cell, but the location of weak oscillators within the network also critically shapes the degree of synchronization for the population.

Thoroughman, Kurt A.; Doyle, Francis J.; Herzog, Erik D.

2012-01-01

258

Weak Radiative Decay of Baryons.  

NASA Astrophysics Data System (ADS)

The purpose of this thesis is to do a quark-level calculation of weak radiative decay of baryons which is complete and also consistent with quantum field-theoretic principles. First, the problem of weak radiative decay of baryons is formulated within the rigorous Bethe-Salpeter formalism. With suitable choice of interpolating fields for the initial and final baryons B and B^ ', a reduction formula for the transition amplitude B to B^ 'gamma is derived in a manner parallel to the standard LSZ reduction procedure. One discovers that the Feynman rules for bound quarks are very different from those for free quarks. In this fashion, one recovers the methodology of analyzing composite particle reactions pioneered by Nishijima and Mandelstam in a way which is easily amenable to generalizations. A suitable parameterization for the Bethe-Salpeter amplitude of a {1over2 }^+ baryon is suggested for calculational purposes. Various subtleties associated with the normalization of this amplitude are discussed. Second, specializing this reduction formula to the case of Sigma^+to pgamma, a detailed analysis of this decay is carried out. Its asymmetry parameter is calculated. Differences with usual quark-model calculations are highlighted and commented upon.

Asthana, Praveer

1988-06-01

259

CERT Coordination Center  

NSDL National Science Digital Library

The CERT Coordination Center is part of the Software Engineering Institute at Carnegie Mellon University. Its primary function is to work with industry to identify and eliminate Internet security vulnerabilities. Additionally, the center analyzes business and personal software to find potentially dangerous flaws that could compromise the system, meaning that both corporate and home users can benefit from the information offered on the Web site. There are continual updates of security advisories, survivability guides, and fixes that can help prevent disasters or speed recovery from them. Step-by-step suggestions make finding and implementing an efficient security practice reasonably painless. A wide range of papers and presentations on Internet and computer security research are available for free download.

1997-01-01

260

Coordinating Group report  

SciTech Connect

In December 1992, western governors and four federal agencies established a Federal Advisory Committee to Develop On-site Innovative Technologies for Environmental Restoration and Waste Management (the DOIT Committee). The purpose of the Committee is to advise the federal government on ways to improve waste cleanup technology development and the cleanup of federal sites in the West. The Committee directed in January 1993 that information be collected from a wide range of potential stakeholders and that innovative technology candidate projects be identified, organized, set in motion, and evaluated to test new partnerships, regulatory approaches, and technologies which will lead to improve site cleanup. Five working groups were organized, one to develop broad project selection and evaluation criteria and four to focus on specific contaminant problems. A Coordinating Group comprised of working group spokesmen and federal and state representatives, was set up to plan and organize the routine functioning of these working groups. The working groups were charged with defining particular contaminant problems; identifying shortcomings in technology development, stakeholder involvement, regulatory review, and commercialization which impede the resolution of these problems; and identifying candidate sites or technologies which could serve as regional innovative demonstration projects to test new approaches to overcome the shortcomings. This report from the Coordinating Group to the DOIT Committee highlights the key findings and opportunities uncovered by these fact-finding working groups. It provides a basis from which recommendations from the DOIT Committee to the federal government can be made. It also includes observations from two public roundtables, one on commercialization and another on regulatory and institutional barriers impeding technology development and cleanup.

Not Available

1994-01-01

261

Improvement of the biocatalytic properties of one phenylacetone monooxygenase mutant in hydrophilic organic solvents.  

PubMed

The presence of different hydrophilic organic solvents or a water soluble polymer such as PEG 4000 led to an enhancement in the enzymatic activity of the M446G mutant of phenylacetone monooxygenase when it is employed in enantioselective sulfoxidations and Baeyer-Villiger reactions. By solvent engineering new substrates were found to be effectively converted by this Baeyer-Villiger monooxygenase. The use of 5% methanol together with the weak anion exchange resin Lewatit MP62 also allows the dynamic kinetic resolution of a set of racemic benzylketones. By this approach (S)-benzylesters could be obtained with high yields and optical purities. PMID:22133439

de Gonzalo, Gonzalo; Rodríguez, Cristina; Rioz-Martínez, Ana; Gotor, Vicente

2012-01-01

262

Solvent cavitation under solvophobic confinement  

NASA Astrophysics Data System (ADS)

The stability of liquids under solvophobic confinement can tip in favor of the vapor phase, nucleating a liquid-to-vapor phase transition that induces attractive forces between confining surfaces. In the case of water adjacent to hydrophobic surfaces, experimental and theoretical evidence support confinement-mediated evaporation stabilization of biomolecular and colloidal assemblies. The macroscopic thermodynamic theory of cavitation under confinement establishes the connection between the size of the confining surfaces, interfacial free energies, and bulk solvent pressure with the critical evaporation separation and interfacial forces. While molecular simulations have confirmed the broad theoretical trends, a quantitative comparison based on independent measurements of the interfacial free energies and liquid-vapor coexistence properties has, to the best of our knowledge, not yet been performed. To overcome the challenges of simulating a large number of systems to validate scaling predictions for a three-dimensional fluid, we simulate both the forces and liquid-vapor coexistence properties of a two-dimensional Lennard-Jones fluid confined between solvophobic plates over a range of plate sizes and reservoir pressures. Our simulations quantitatively agree with theoretical predictions for solvent-mediated forces and critical evaporation separations once the length dependence of the solvation free energy of an individual confining plate is taken into account. The effective solid-liquid line tension length dependence results from molecular scale correlations for solvating microscopic plates and asymptotically decays to the macroscopic value for plates longer than 150 solvent diameters. The success of the macroscopic thermodynamic theory at describing two-dimensional liquids suggests application to surfactant monolayers to experimentally confirm confinement-mediated cavitation.

Ashbaugh, Henry S.

2013-08-01

263

Solvent refined coal (SRC) process  

SciTech Connect

This report summarizes the progress of the Solvent Refined Coal (SRC) project by The Pittsburg and Midway Coal Mining Co. at the SRC Pilot Plant in Fort Lewis, Washington and the Gulf Science and Technology Company Process Development Unit (P-99) in Harmarville, Pennsylvania, for the Department of Energy during the month of October, 1980. The Fort Lewis Pilot Plant was shut down the entire month of October, 1980 for inspection and maintenance. PDU P-99 completed two runs during October investigating potential start-up modes for the Demonstration Plant.

Not Available

1980-12-01

264

Aromatic as well as aliphatic hydrocarbon solvent axonopathy.  

PubMed

Superfund sites that contain mixtures of aromatic and aliphatic solvents represent an undefined health hazard. After prolonged exposure to relatively high levels of certain aliphatic solvents (e.g. n-hexane, 2-hexanone), humans and animals develop a dose-dependent neurodegeneration that occurs clinically as a symmetrical peripheral neuropathy. This is triggered by the action of 2,5-hexanedione (1,2-diacetylethane), a 1,4-diketone (gamma-diketone) metabolite that targets proteins required for the maintenance of neuronal (and testicular Sertoli cell) integrity. Certain aromatic solvents (1,2-diethylbenzene, 1,2,4-triethylbenzene) cause electrophysiological changes consistent with sensorimotor neuropathy in rodents, but the underlying mechanisms and pathogenesis are unclear. Our recent studies show that the o-diacetyl derivative and likely metabolite of 1,2-diethylbenzene, 1,2-diacetylbenzene, behaves as a neurotoxic (aromatic) gamma-diketone of high neurotoxic potency. Rats treated with 1,2-diacetylbenzene develop limb weakness associated with proximal, neurofilament-filled giant axonal swellings comparable to those seen in animals treated with the potent 3,4-dimethyl derivative of 2,5-hexanedione. The blue chromogen induced by treatment with 1,2-diacetylbenzene is under study as a possible urinary biomarker of exposure to aromatic solvents (e.g. 1,2-diethylbenzene, tetralin) with neurotoxic potential. Development and validation of sensitive new biomarkers, especially for non-cancer endpoints, will aid in assessing the health risk associated with exposure to hazardous substances at Superfund sites. PMID:12018006

Spencer, Peter S; Kim, Min Sun; Sabri, Mohammad I

2002-03-01

265

A COMPARISON OF PHYSICAL SOLVENTS FOR ACID GAS REMOVAL  

Microsoft Academic Search

Physical solvents such as DEPG (Selexol™ or Coastal AGR®), NMP or N-Methyl-2- Pyrrolidone (Purisol®), Methanol (Rectisol®), and Propylene Carbonate (Fluor Solvent™) are becoming increasingly popular as gas treating solvents, especially for coal gasification applications. Physical solvents tend to be favored over chemical solvents when the concentration of acid gases or other impurities is very high. In addition, physical solvents can

Barry Burr; Lili Lyddon

266

Weak Links as Stabilizers of Complex Systems  

NASA Astrophysics Data System (ADS)

In the previous chapters we learned how weak links stabilize complex systems. The classical study of Granovetter (1973) demonstrated that weak links help the cohesion of society (see Chap. 1). Weak links are necessary for small-worldness, emerging in parallel with topological scale-freeness, and making a key contribution to the formation of nestedness (see Chap. 2). Weak links buffer noise, help relaxation, form barriers against cascading failures, and stabilize the coupled oscillators of bottom networks (see Chap. 3).

Csermely, Peter

267

Rational solvent selection for cooling crystallizations  

SciTech Connect

The development of a successful crystallization process for purification and isolation of an organic compound requires the selection of a suitable solvent or solvent mixture; to date, no logical method has been established for determining the best solvent combination. The process chemist or engineer often employs a trial-and-error procedure to identify an appropriate solvent system, the success of which is dependent on experience and intuition. This paper describes a strategy for choosing crystallization solvents based upon equilibrium limits. The approach utilizes a group-contribution method (UNIFAC) to predict a value for the activity coefficient of the solute in a given solvent system at the saturation point. This value is then used to calculate the solubility of the solute at a high'' temperature and a low'' temperature. The resulting solubility values determine the maximum theoretical yield for the process. Both quantities are used to rank order solvents and/or their mixtures relative to one another according to their solvent power and potential process yield. Several examples illustrating the successful application of this method are described, and potential improvements to the algorithm are discussed. Implementation of this strategy will reduce product cycle time, minimize solvent usage, and allow identification of cheaper solvent alternatives.

Nass, K.K. (Eastman Kodak Co., Rochester, NY (United States). Chemicals Development Div.)

1994-06-01

268

Weakness In Grand Rapids Housing Prices  

Microsoft Academic Search

The weak housing market has been one of the most important business stories of 2007. A weak housing market decreases the value of a house. As a result, the wealth of the individual consumer drops, decreasing their financial security. There are many ways to measure the weakness in the housing market such as the number of house sales, foreclosure rates,

Paul N Isely; Elvira Yaparova

2008-01-01

269

Superluminal tunnelling times as weak values  

Microsoft Academic Search

We consider the tunnelling particle as a pre- and post-selected system and prove that the tunnelling time is the expectation value of the position of a ‘clock’ degree of freedom weakly coupled to it. Such a value, called a ‘weak value’, typically falls outside the eigenvalue spectrum of the operator. The appearance of unusual weak values has been associated with

Yakir Aharonov; Noam Erez; Benni Reznik

2003-01-01

270

Progressive leg pain and weakness.  

PubMed

A 54-year-old man presented with progressive asymmetric leg pain and weakness. He had a history of invasive squamous cell carcinoma that was fully treated 2 years earlier. His leg symptoms progressed relentlessly during several months. Imaging studies demonstrated enhancement of the cauda equina and leptomeninges of the lower spinal cord. Initial cerebrospinal fluid examination showed an elevated protein concentration and lymphocytic pleocytosis with no malignant cells on cytological analysis. There was short-term improvement in symptoms and cerebrospinal fluid abnormalities with intravenous steroids. Two additional cerebrospinal fluid studies showed normal cytological findings, elevated IgG synthesis, and elevated antibody titers to varicella-zoster virus. Over time, the patient worsened, developed cranial neuropathies, and ultimately died. The pathological diagnosis and the approach to the clinical data are discussed. PMID:23440264

Navalkele, Digvijaya D; Georgescu, Maria-Magdalena; Burns, Dennis K; Greenberg, Tasha; Vernino, Steven

2013-04-01

271

Weak KAM for commuting Hamiltonians  

NASA Astrophysics Data System (ADS)

For two commuting Tonelli Hamiltonians, we recover the commutation of the Lax-Oleinik semi-groups, a result of Barles and Tourin (2001 Indiana Univ. Math. J. 50 1523-44), using a direct geometrical method (Stoke's theorem). We also obtain a 'generalization' of a theorem of Maderna (2002 Bull. Soc. Math. France 130 493-506). More precisely, we prove that if the phase space is the cotangent of a compact manifold then the weak KAM solutions (or viscosity solutions of the critical stationary Hamilton-Jacobi equation) for G and for H are the same. As a corollary we obtain the equality of the Aubry sets and of the Peierls barrier. This is also related to works of Sorrentino (2009 On the Integrability of Tonelli Hamiltonians Preprint) and Bernard (2007 Duke Math. J. 136 401-20).

Zavidovique, M.

2010-04-01

272

Anomalous diffusion and weak nonergodicity.  

PubMed

Ergodic behavior of the class of G processes G(t)=?(t(m))(t)du?K(t,u)?(u)-?(t(m))(0)du?K(0,u)?(u), (?(t))=0, (?(t)?(s))=?(|t-s|) is examined. Ergodicproperties are only G extensions of normal diffusion (K=1) and of Mandelbrot-Van Ness fractional diffusion [K(t,u)=K(t-u), t(m)?-?]. Any deviation from these two types results in weak ergodicity breaking which thus is neither exceptional nor limited to some specific events but is typical for much wider class of processes. G processes driven by ?(t) with nonvanishing correlations are important for describing transport in strongly nonequilibrium systems and may be responsible for peculiarities of diffusion found in biological, glassy, and nanoscale systems. PMID:21797335

Fuli?ski, A

2011-06-01

273

Anomalous diffusion and weak nonergodicity  

NASA Astrophysics Data System (ADS)

Ergodic behavior of the class of G processes G(t)=?tmtduK(t,u)?(u)-?tm0duK(0,u)?(u), =0, =?(|t-s|) is examined. Ergodic properties are only G extensions of normal diffusion (K=1) and of Mandelbrot-Van Ness fractional diffusion [K(t,u)=K(t-u), tm?-?]. Any deviation from these two types results in weak ergodicity breaking which thus is neither exceptional nor limited to some specific events but is typical for much wider class of processes. G processes driven by ?(t) with nonvanishing correlations are important for describing transport in strongly nonequilibrium systems and may be responsible for peculiarities of diffusion found in biological, glassy, and nanoscale systems.

Fuli?ski, A.

2011-06-01

274

[Spectroscopic investigation of the properties of axial coordination of tailed metalloporphyrins].  

PubMed

The properties of axial coordination of nitrogenous ligands to four tailed metalloporphyrins, O-PyTPPFe ( III ) Cl, O-ImTPPMn ( III ) Cl, O-PyTPPMn ( III ) Cl and O-ImTPPFe ( III ) Cl, has been investigated by UV-Visible spectral techniques. The effects of terminal groups, solvents and metal center were examined and discussed. PMID:15810219

Jiao, X; Duna, X; Huang, J; Ji, L

1997-06-01

275

Lanthanide-organic complexes based on polyoxometalates: Solvent effect on the luminescence properties  

SciTech Connect

A series of lanthanide-organic complexes based on polyoxometalates (POMs) [Ln{sub 2}(DNBA){sub 4}(DMF){sub 8}][W{sub 6}O{sub 19}] (Ln=La(1), Ce(2), Sm(3), Eu(4), Gd(5); DNBA=3,5-dinitrobenzoate; DMF=N,N-dimethylformamide) has been synthesized. These complexes consist of [W{sub 6}O{sub 19}]{sup 2-} and dimeric [Ln{sub 2}(DNBA){sub 4}(DMF){sub 8}]{sup 2+} cations. The luminescence properties of 4 are measured in solid state and different solutions, respectively. Notably, the emission intensity increases gradually with the increase of solvent permittivity, and this solvent effect can be directly observed by electrospray mass spectrometry (ESI-MS). The analyses of ESI-MS show that the eight coordinated solvent DMF units of dimeric cation are active. They can move away from dimeric cations and exchange with solvent molecules. Although the POM anions escape from 3D supramolecular network, the dimeric state structure of [Ln{sub 2}(DNBA){sub 4}]{sup 2+} remains unchanged in solution. The conservation of red luminescence is attributed to the maintenance of the aggregated state structures of dimeric cations. - Graphical abstract: 3D POMs-based lanthanide-organic complexes performed the solvent effect on the luminescence property. The origin of such solvent effect can be understood and explained on the basis of the existence of coordinated active sites by the studies of ESI-MS. Highlights: Black-Right-Pointing-Pointer The solvent effect on the luminescence property of POMs-based lanthanide-organic complexes. Black-Right-Pointing-Pointer ESI-MS analyses illuminate the correlation between the structure and luminescence property. Black-Right-Pointing-Pointer The dimeric cations have eight active sites of solvent coordination. Black-Right-Pointing-Pointer The aggregated state structure of dimer cation remains unchanged in solution. Black-Right-Pointing-Pointer Luminescence associating with ESI-MS is a new method for investigating the interaction of complex and solvent.

Tang Qun [Key Laboratory of Polyoxometalate Science of Ministry of Education, College of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China); Liu Shuxia, E-mail: liusx@nenu.edu.cn [Key Laboratory of Polyoxometalate Science of Ministry of Education, College of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China); Liang Dadong; Ma Fengji; Ren Guojian; Wei Feng; Yang Yuan; Li Congcong [Key Laboratory of Polyoxometalate Science of Ministry of Education, College of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China)

2012-06-15

276

Reducing Systematic Error in Weak Lensing Cluster Surveys  

NASA Astrophysics Data System (ADS)

Weak lensing provides an important route toward collecting samples of clusters of galaxies selected by mass. Subtle systematic errors in image reduction can compromise the power of this technique. We use the B-mode signal to quantify this systematic error and to test methods for reducing this error. We show that two procedures are efficient in suppressing systematic error in the B-mode: (1) refinement of the mosaic CCD warping procedure to conform to absolute celestial coordinates and (2) truncation of the smoothing procedure on a scale of 10'. Application of these procedures reduces the systematic error to 20% of its original amplitude. We provide an analytic expression for the distribution of the highest peaks in noise maps that can be used to estimate the fraction of false peaks in the weak-lensing ?-signal-to-noise ratio (S/N) maps as a function of the detection threshold. Based on this analysis, we select a threshold S/N = 4.56 for identifying an uncontaminated set of weak-lensing peaks in two test fields covering a total area of ~3 deg2. Taken together these fields contain seven peaks above the threshold. Among these, six are probable systems of galaxies and one is a superposition. We confirm the reliability of these peaks with dense redshift surveys, X-ray, and imaging observations. The systematic error reduction procedures we apply are general and can be applied to future large-area weak-lensing surveys. Our high-peak analysis suggests that with an S/N threshold of 4.5, there should be only 2.7 spurious weak-lensing peaks even in an area of 1000 deg2, where we expect ~2000 peaks based on our Subaru fields. Based in part on data collected at Subaru Telescope and obtained from the SMOKA, which is operated by the Astronomy Data Center, National Astronomical Observatory of Japan.

Utsumi, Yousuke; Miyazaki, Satoshi; Geller, Margaret J.; Dell'Antonio, Ian P.; Oguri, Masamune; Kurtz, Michael J.; Hamana, Takashi; Fabricant, Daniel G.

2014-05-01

277

An anionic microporous polymer network prepared by the polymerization of weakly coordinating anions.  

PubMed

Organic zeolite: A microporous, covalent organic network with high surface area was synthesized by polymerization of [B(C6 F4 Br)4 ](-) . The countercations, located within the pore channels, are highly accessible and can be easily exchanged, comparable to the extra-framework cations in zeolites. In this way a [Mn(II) (bpy)](2+) complex can be synthesized and immobilized in the network. PMID:24151252

Fischer, Sabrina; Schmidt, Johannes; Strauch, Peter; Thomas, Arne

2013-11-11

278

Glycerol and glycerol carbonate as ultraviscous solvents for mixture analysis by NMR  

NASA Astrophysics Data System (ADS)

NMR of weakly polar analytes in an apolar ultraviscous solvent has recently been proposed for mixture analysis as a pertinent alternative to the DOSY experiment. The present article reports the first use of glycerol and glycerol carbonate as polar solvents for the NMR analysis of a model mixture of dipeptides. This work demonstrates the high potentiality of these solvents for the analysis of mixtures made of polar and potentially bioactive compounds. Medium-sized molecules slowly reorient in glycerol and glycerol carbonate under particular temperature conditions, so that solute resonances may show spin diffusion in NOESY spectra, thus opening the way to mixture analysis. Glycerol and glycerol carbonate have turned out to be ultraviscous solvents of choice for the individualization of four structurally close mixed dipeptides: Leu-Val, Leu-Tyr, Gly-Tyr and Ala-Tyr by means of 1D and 2D NOESY experiments. Selective sample excitation and signal detection were implemented to eliminate the intense proton signals of the non-deuterated solvents. Moreover, the recording of a multiplet selective 2D NOESY-TOCSY has shown that the analytical power of NMR in highly viscous solvents is not limited to the extraction of mixture component 1D subspectra but may also yield some supplementary information about atom connectivity within components.

Lameiras, Pedro; Boudesocque, Leslie; Mouloungui, Zéphirin; Renault, Jean-Hugues; Wieruszeski, Jean-Michel; Lippens, Guy; Nuzillard, Jean-Marc

2011-09-01

279

Process for solvent refining of coal using a denitrogenated and dephenolated solvent  

SciTech Connect

A process is disclosed for the solvent refining of nonanthracitic coal at elevated temperatures and pressure in a hydrogen atmosphere using a hydrocarbon solvent which before being recycled in the solvent refining process is subjected to chemical treatment to extract substantially all nitrogenous and phenolic constituents from the solvent so as to improve the conversion of coal and the production of oil in the solvent refining process. The solvent refining process can be either thermal or catalytic. The extraction of nitrogenous compounds can be performed by acid contact such as hydrogen chloride or fluoride treatment, while phenolic extraction can be performed by caustic contact or contact with a mixture of silica and alumina.

Carg, D.; Givens, E.N.

1984-09-18

280

Solvent dependent photophysical properties of dimethoxy curcumin  

NASA Astrophysics Data System (ADS)

Dimethoxy curcumin (DMC) is a methylated derivative of curcumin. In order to know the effect of ring substitution on photophysical properties of curcumin, steady state absorption and fluorescence spectra of DMC were recorded in organic solvents with different polarity and compared with those of curcumin. The absorption and fluorescence spectra of DMC, like curcumin, are strongly dependent on solvent polarity and the maxima of DMC showed red shift with increase in solvent polarity function (?f), but the above effect is prominently observed in case of fluorescence maxima. From the dependence of Stokes' shift on solvent polarity function the difference between the excited state and ground state dipole moment was estimated as 4.9 D. Fluorescence quantum yield (?f) and fluorescence lifetime (?f) of DMC were also measured in different solvents at room temperature. The results indicated that with increasing solvent polarity, ?f increased linearly, which has been accounted for the decrease in non-radiative rate by intersystem crossing (ISC) processes.

Barik, Atanu; Indira Priyadarsini, K.

2013-03-01

281

Organic solvents in the pharmaceutical industry.  

PubMed

Organic solvents are commonly used in the pharmaceutical industry as reaction media, in separation and purification of synthesis products and also for cleaning of equipment. This paper presents some aspects of organic solvents utilization in an active pharmaceutical ingredient and a drug product manufacturing process. As residual solvents are not desirable substances in a final product, different methods for their removal may be used, provided they fulfill safety criteria. After the drying process, analyses need to be performed to check if amounts of solvents used at any step of the production do not exceed acceptable limits (taken from ICH Guideline or from pharmacopoeias). Also new solvents like supercritical fluids or ionic liquids are developed to replace "traditional" organic solvents in the pharmaceutical production processes. PMID:20210074

Grodowska, Katarzyna; Parczewski, Andrzej

2010-01-01

282

Solvent Signal is a NMR Concentration Reference  

PubMed Central

We propose that the NMR solvent signal be utilized as a universal concentration reference because most solvents can be observed by NMR, and solvent concentrations can be readily calculated or determined independently. In particular, a highly protonated solvent such as water can serve as a primary concentration standard for its stability, availability and ease of observation. The potential issues of radiation damping associated with a strong NMR signal can be alleviated by small pulse angle excitations. The solvent signal then can be detected by the NMR receiver with the same efficiency as a dilute analyte. We demonstrated that the analyte's proton concentration can be accurately determined from 4 ?M to more than 100 M, referenced by solvent (water) protons of concentrations more than 10 M. The proposed method is robust and indifferent to probe tuning, and does not require any additional concentration standard.

Mo, Huaping; Raftery, Daniel

2009-01-01

283

Femtosecond dynamics in hydrogen-bonded solvents  

SciTech Connect

We present results on the ultrafast dynamics of pure hydrogen-bonding solvents, obtained using femtosecond Fourier-transform optical-heterodyne-detected, Raman-induced Kerr effect spectroscopy. Solvent systems we have studied include the formamides, water, ethylene glycol, and acetic acid. Inertial and diffusive motions are clearly resolved. We comment on the effect that such ultrafast solvent motions have on chemical reactions in solution.

Castner, E.W. Jr.; Chang, Y.J.

1993-09-01

284

Process for hydrogenating coal and coal solvents  

DOEpatents

A novel process is described for the hydrogenation of coal by the hydrogenation of a solvent for the coal in which the hydrogenation of the coal solvent is conducted in the presence of a solvent hydrogenation catalyst of increased activity, wherein the hydrogenation catalyst is produced by reacting ferric oxide with hydrogen sulfide at a temperature range of 260.degree. C. to 315.degree. C. in an inert atmosphere to produce an iron sulfide hydrogenation catalyst for the solvent. Optimally, the reaction temperature is 275.degree. C. Alternately, the reaction can be conducted in a hydrogen atmosphere at 350.degree. C.

Tarrer, Arthur R. (Auburn, AL); Shridharani, Ketan G. (Auburn, AL)

1983-01-01

285

Organic solvent use in enterprises in Japan.  

PubMed

This study was initiated to elucidate possible changes in types of organic solvents (to be called solvents in short) used in enterprises in Japan through comparison of current solvent types with historical data since 1983. To investigate current situation in solvent use in enterprises, surveys were conducted during one year of 2009 to 2010. In total, workroom air samples in 1,497 unit workplaces with solvent use were analyzed in accordance with regulatory requirements. Typical use pattern of solvents was as mixtures, accounting for >70% of cases. Adhesives spreading (followed by adhesion) was relatively common in small-scale enterprises, whereas printing and painting work was more common in middle-scale ones, and solvent use for testing and research purpose was basically in large-scaled enterprises. Through-out printing, painting, surface coating and adhesive application, toluene was most common (being detected in 49 to 82% of workplaces depending on work types), whereas isopropyl alcohol was most common (49%) in degreasing, cleaning and wiping workplaces. Other commonly used solvents were methyl alcohol, ethyl acetate and acetone (33 to 37%). Comparison with historical data in Japan and literature-retrieved data outside of Japan all agreed with the observation that toluene is the most commonly used solvent. Application of trichloroethylene and 1,1,1-trichloroethane, once common in 1980s, has ceased to exist in recent years. PMID:21697614

Nagasawa, Yasuhiro; Ukai, Hirohiko; Okamoto, Satoru; Samoto, Hajime; Itoh, Kenji; Moriguchi, Jiro; Sakuragi, Sonoko; Ohashi, Fumiko; Takada, Shiro; Kawakami, Tetsuya; Ikeda, Masayuki

2011-01-01

286

Lipid membranes as solvents for carbon nanoparticles.  

PubMed

Fullerene is scarcely soluble in most solvents, including alkanes. Yet, it has been shown that C60 dissolves in lipid bilayers, whose interior is chemically identical to alkanes. Here, we use molecular simulations to explain why lipid bilayers are better than alkanes at dissolving fullerene clusters. Fullerene aggregation is driven by entropy, but enthalpic contributions determine the difference between alkanes and bilayers. Surprisingly, confinement and chain alignment in the bilayer do not affect fullerene aggregation, while solvent density and the perturbation of solvent-solvent interactions are key factors. PMID:24580709

Barnoud, Jonathan; Rossi, Giulia; Monticelli, Luca

2014-02-14

287

EXAFS Study into the Speciation of Metal Salts Dissolved in Ionic Liquids and Deep Eutectic Solvents.  

PubMed

The speciation of metals in solution controls their reactivity, and this is extremely pertinent in the area of metal salts dissolved in ionic liquids. In the current study, the speciation of 25 metal salts is investigated in four deep eutectic solvents (DESs) and five imidazolium-based ionic liquids using extended X-ray absorption fine structure. It is shown that in diol-based DESs M(I) ions form [MCl2](-) and [MCl3](2-) complexes, while all M(II) ions form [MCl4](2-) complexes, with the exception of Ni(II), which exhibits a very unusual coordination by glycol molecules. This was also found in the X-ray crystal structure of the compound [Ni(phen)2(eg)]Cl2·2eg (eg = ethylene glycol). In a urea-based DES, either pure chloro or chloro-oxo coordination is observed. In [C6mim][Cl] pure chloro complexation is also observed, but coordination numbers are smaller (typically 3), which can be explained by the long alkyl chain of the cation. In [C2mim][SCN] metal ions are entirely coordinated by thiocyanate, either through the N or the S atom, depending on the hardness of the metal ion according to the hard-soft acid-base principle. With weaker coordinating anions, mixed coordination between solvent and solute anions is observed. The effect of hydrate or added water on speciation is insignificant for the diol-based DESs and small in other liquids with intermediate or strong ligands. One of the main findings of this study is that, with respect to metal speciation, there is no fundamental difference between deep eutectic solvents and classic ionic liquids. PMID:24897923

Hartley, Jennifer M; Ip, Chung-Man; Forrest, Gregory C H; Singh, Kuldip; Gurman, Stephen J; Ryder, Karl S; Abbott, Andrew P; Frisch, Gero

2014-06-16

288

Solvent anode for plutonium purification  

SciTech Connect

The purpose of this study is to develop a technique to allow complete oxidation of plutonium from the anode during plutonium electrorefining. This will eliminate the generation of a ''spent'' anode heel which requires further treatment for recovery. Our approach is to employ a solvent metal in the anode to provide a liquid anode pool throughout electrorefining. We use molten salts and metals in ceramic crucibles at 700/sup 0/C. Our goal is to produce plutonium metal at 99.9% purity with oxidation and transfer of more than 98% of the impure plutonium feed metal from the anode into the salt and product phases. We have met these criteria in experiments on the 100 to 1000 g scale. We plan to scale our operations to 4 kg of feed plutonium and to optimize the process parameters.

Bowersox, D.F.; Fife, K.W.; Christensen, D.C.

1986-01-01

289

Chlorophyll a self-assembly in polar solvent-water mixtures.  

PubMed

The conversion of chlorophyll a (Chl a) monomers into large aggregates in six polar solvents upon addition of water has been studied by means of absorption, fluorescence spectroscopy and fluorescence lifetime measurements for the purpose of elucidating the various environmental factors promoting Chl a self-assembly and determining the type of its organization. Two empirical solvent parameter scales were used for quantitative characterization of the different solvation properties of the solvents and their mixtures with water. The mole fractions of water f1/2 giving rise to the midpoint values of the relative fluorescence quantum yield were determined for each solvent, and then various solvent-water mixture parameters for the f1/2 values were compared. On the basis of their comparison, it is concluded that the hydrogen-bonding ability and the dipole-dipole interactions (function of the dielectric constant) of the solvent-water mixtures are those that promote Chl a self-assembly. The influence of the different nature of the non-aqueous solvents on the Chl aggregation is manifested by both the different water contents required to induce Chl monomer-->aggregate transition and the formation of two types of aggregates at the completion of the transition: species absorbing at 740-760 nm (in methanol, ethanol, acetonitrile, acetone) and at 667-670 nm (in pyridine and tetrahydrofuran). It is concluded that the type of Chl organization depends on the coordination ability and the polarizability (function of the index of refraction) of the organic solvent. The ordering of the solvents with respect to the f1/2 values--methanol < ethanol < acetonitrile < acetone < pyridine < tetrahydrofuran--yielded a typical lyotropic (Hofmeister) series. On the basis of this solvent ordering and the disparate effects of the two groups of solvents on the Chl a aggregate organization, it is pointed out that the mechanism of Chl a self-assembly in aqueous media can be considered a manifestation of the Hofmeister effect, as displayed in the lipid-phase behavior (Koynova et al., Eur. J. Biophys. 25, 261-274, 1997). It relates to the solvent ability to modify the bulk structure and to distribute unevenly between the Chl-water interface and bulk liquid. PMID:10649892

Vladkova, R

2000-01-01

290

Quantitation of buried contamination by use of solvents. [degradation of silicone polymers by amine solvents  

NASA Technical Reports Server (NTRS)

Spore recovery form cured silicone potting compounds using amine solvents to degrade the cured polymers was investigated. A complete list of solvents and a description of the effect of each on two different silicone polymers is provided.

Pappas, S. P.; Hsiao, Y. C.; Hill, L. W.

1973-01-01

291

Wide electrochemical window solvents for use in electrochemical devices and electrolyte solutions incorporating such solvents  

DOEpatents

The present invention relates to electrolyte solvents for use in liquid or rubbery electrolyte solutions. Specifically, this invention is directed to boron-containing electrolyte solvents and boron-containing electrolyte solutions.

Angell, Charles Austen (Mesa, AZ); Zhang, Sheng-Shui (Tucson, AZ); Xu, Kang (Tempe, AZ)

1998-01-01

292

Organic Solvent-Tolerant Bacterium Which Secretes an Organic Solvent-Stable Proteolytic Enzyme  

PubMed Central

A bacterial strain which can be grown in a medium containing organic solvents and can secrete a proteolytic enzyme was isolated and identified as Pseudomonas aeruginosa. The strain was derived by the following two-step procedures: high proteolytic enzyme producers were first isolated by the usual method, and then the organic solvent-tolerant microorganism was selected from these high-rate proteolytic enzyme producers. The proteolytic activity of the supernatant of the culture was stable in the presence of various organic solvents. The stability of the enzyme in the presence of organic solvents, of which the values of the logarithm of the partition coefficient (log P) were equal to or more than 3.2, was almost the same as that in the absence of organic solvents. It is expected that both the solvent-tolerant microorganism and the solvent-stable enzyme produced by this strain can be used as catalysts for reactions in the presence of organic solvents.

Ogino, H.; Yasui, K.; Shiotani, T.; Ishihara, T.; Ishikawa, H.

1995-01-01

293

Cleanup of 7. 5% tributyl phosphate/n-paraffin solvent-extraction solvent  

SciTech Connect

The HM process at the Savannah River Plant uses 7.5% tributyl phosphate in n-paraffin as an extraction solvent. During use, the solvent is altered due to hydrolysis and radiolysis, forming materials which influence product losses, product decontamination, and separation efficiencies. Laboratory studies to improve online solvent cleaning have shown that carbonate washing, although removing residual solvent activity, does not remove binding ligands which hold fission products in the solvent. Treatment of solvent by an alumina adsorption process removes binding ligands and significantly improves recycle solvent performance. Both laboratory work defining a full-scale alumina adsorption process and the use of the process to clean HM process first cycle solvent is discussed.

Reif, D.J.

1987-02-01

294

Prussian blue nanospheres synthesized in deep eutectic solvents  

NASA Astrophysics Data System (ADS)

A novel route for controlled synthesis of Prussian blue nanospheres (PB NSs) with different sizes by using deep eutectic solvents (DES) as both solvent and template provider was demonstrated. The size-controlled PB NSs were obtained directly by the coordination of Fe(CN)64- ion with Fe3+ ion in the DES. The probable mechanism of formation of PB NSs was discussed based on the characterization results of UV-visible, X-ray diffraction, X-ray photoelectronic spectrum and transfer electron microscopy. Furthermore, the electrochemical and electrocatalytic properties of the synthesized PB NSs were investigated, and it has demonstrated that the PB NSs exhibited excellent catalytic activity for H2O2 reduction, and then extended this strategy to glucose sensing, by detecting H2O2 formed from the enzymatic reaction of glucose oxidase with its substrate glucose. The linear calibration range for glucose was from 0.9 ?M to 0.12 mM, with a correlation coefficient of 0.998. The limit of detection was 0.3 ?M and the sensitivity was 61.7 A cm-2 M-1. The present study provides a general platform for the controlled synthesis of novel nanomaterials in DES and can be extended to other optical, electronic and magnetic nanocompounds.A novel route for controlled synthesis of Prussian blue nanospheres (PB NSs) with different sizes by using deep eutectic solvents (DES) as both solvent and template provider was demonstrated. The size-controlled PB NSs were obtained directly by the coordination of Fe(CN)64- ion with Fe3+ ion in the DES. The probable mechanism of formation of PB NSs was discussed based on the characterization results of UV-visible, X-ray diffraction, X-ray photoelectronic spectrum and transfer electron microscopy. Furthermore, the electrochemical and electrocatalytic properties of the synthesized PB NSs were investigated, and it has demonstrated that the PB NSs exhibited excellent catalytic activity for H2O2 reduction, and then extended this strategy to glucose sensing, by detecting H2O2 formed from the enzymatic reaction of glucose oxidase with its substrate glucose. The linear calibration range for glucose was from 0.9 ?M to 0.12 mM, with a correlation coefficient of 0.998. The limit of detection was 0.3 ?M and the sensitivity was 61.7 A cm-2 M-1. The present study provides a general platform for the controlled synthesis of novel nanomaterials in DES and can be extended to other optical, electronic and magnetic nanocompounds. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr31830j

Sheng, Qinglin; Liu, Ruixiao; Zheng, Jianbin

2012-10-01

295

Desorption of chlorine organic solvents  

SciTech Connect

Adsorption methods are being used more and more widely to treat gaseous discharges containing chlorohydrocarbons. However, recovery of the chlorohydrocarbons has not been studied sufficiently, and the desorption of the solvents with steam is particularly understudied. We investigated desorption of a number of solvents from industrial active carbon AR-3. Desorption was done with live steam in the 105 to 150/sup 0/C. It can be seen from the data that with an increase of the molecular weight of the chlorohydrocarbon, the process of desorption slows down. This is clearly due to the fact that with an increase of the number of chlorine atoms in the molecule there is an increase of dispersion interaction (size of parachors) and latent heat of vaporization, which cause a decrease of the degree of desorption. The rate of desorption increases with an increase in temperature, but most of the investigated chlorine derivatives detach a chlorine ion at elevated temperature in the presence of water and carbon, with formation of HCl, which causes severe equipment corrosion. In addition, phosgene (in the decomposition of C/sub 2/HCl/sub 3/), chlorine organic acids and certain other toxic compounds may be produced. Thus, to reduce the rate of hydrolysis in the desorption of chlorohydrocarbons, especially polychlorinated ones, one should use steam with minimum possible temperature (no more than 110/sup 0/C) with a desorption time of no more than 30 minutes for poorly adsorbable compounds and no more than 45 to 60 minutes for readily absorbable ones. Here the degree of desorption of poorly absorbed compounds is about 100% while that of the readily absorbed ones is from 50 to 75%. The results were used in the design of units for recovery of methylene chloride, dichloroethane and trichloroethylene.

Petrova, N.I.; Nikolaev, K.M.

1982-03-01

296

Verdier specialization via weak factorization  

NASA Astrophysics Data System (ADS)

Let X? V be a closed embedding, with V? X nonsingular. We define a constructible function ? X, V on X, agreeing with Verdier's specialization of the constant function 1 V when X is the zero-locus of a function on V. Our definition is given in terms of an embedded resolution of X; the independence of the choice of resolution is obtained as a consequence of the weak factorization theorem of Abramovich-Karu-Matsuki-W?odarczyk. The main property of ? X, V is a compatibility with the specialization of the Chern class of the complement V? X. With the definition adopted here, this is an easy consequence of standard intersection theory. It recovers Verdier's result when X is the zero-locus of a function on V. Our definition has a straightforward counterpart ? X, V in a motivic group. The function ? X, V and the corresponding Chern class c SM( ? X, V ) and motivic aspect ? X, V all have natural `monodromy' decompositions, for any X? V as above. The definition also yields an expression for Kai Behrend's constructible function when applied to (the singularity subscheme of) the zero-locus of a function on V.

Aluffi, Paolo

2013-04-01

297

Weak percolation on multiplex networks  

NASA Astrophysics Data System (ADS)

Bootstrap percolation is a simple but nontrivial model. It has applications in many areas of science and has been explored on random networks for several decades. In single-layer (simplex) networks, it has been recently observed that bootstrap percolation, which is defined as an incremental process, can be seen as the opposite of pruning percolation, where nodes are removed according to a connectivity rule. Here we propose models of both bootstrap and pruning percolation for multiplex networks. We collectively refer to these two models with the concept of "weak" percolation, to distinguish them from the somewhat classical concept of ordinary ("strong") percolation. While the two models coincide in simplex networks, we show that they decouple when considering multiplexes, giving rise to a wealth of critical phenomena. Our bootstrap model constitutes the simplest example of a contagion process on a multiplex network and has potential applications in critical infrastructure recovery and information security. Moreover, we show that our pruning percolation model may provide a way to diagnose missing layers in a multiplex network. Finally, our analytical approach allows us to calculate critical behavior and characterize critical clusters.

Baxter, Gareth J.; Dorogovtsev, Sergey N.; Mendes, José F. F.; Cellai, Davide

2014-04-01

298

Effect of Ligand Structural Isomerism in Formation of Calcium Coordination Networks  

SciTech Connect

Using different structural isomers (2,5-; 2,4-; 2;6-; 3,4-; 3,5-) of pyridinedicarboxylic acid, nine calcium-based coordination networks were synthesized under hydro-/solvothermal conditions and/or were produced via solvent recrystallization of previously synthesized compounds. The coordination networks reported were characterized using single crystal X-ray diffraction and thermal methods. They show diverse structural topologies, depending on the ligand geometry and coordinated solvent molecules, with inorganic connectivity motifs ranging from isolated octahedra to infinite chains, layer and a three-dimensional dense framework. The as-synthesized and desolvated networks further show structural transformation to hydrated phases through dissolution/reformation pathways. The process is likely driven by the high hydration energy of the calcium metal center.

Plonka A. M.; Parise J.; Banerjee, D.

2012-03-28

299

Channel Coordination and Quantity Discounts  

Microsoft Academic Search

This paper presents a model for analyzing the impact of joint decision policies on channel coordination in a system consisting of a supplier and a group of homogeneous buyers. The joint decision policy characterized by the unit selling price and the order quantity is coordinated through quantity discounts and franchise fees. Both the annual demand rate and the operating cost---including

Z. Kevin Weng

1995-01-01

300

Scalable Coordination in Sensor Networks  

Microsoft Academic Search

Network sensorsthose that coordinate amongst themselvesto achieve a larger sensing taskwill revolutionizeinformation gathering and processing both in urban environmentsand in inhospitable terrain. The sheer numbers ofthese sensors and the expected dynamics in these environmentspresent unique challenges in the design of unattendedautonomous sensor networks. These challenges lead us tohypothesize that sensor network coordination applicationsmay need to be structured dierently from...

Deborah Estrin; John Heidemann; Ramesh Govindan

1999-01-01

301

Coordinate Dependence of Variability Analysis  

PubMed Central

Analysis of motor performance variability in tasks with redundancy affords insight about synergies underlying central nervous system (CNS) control. Preferential distribution of variability in ways that minimally affect task performance suggests sophisticated neural control. Unfortunately, in the analysis of variability the choice of coordinates used to represent multi-dimensional data may profoundly affect analysis, introducing an arbitrariness which compromises its conclusions. This paper assesses the influence of coordinates. Methods based on analyzing a covariance matrix are fundamentally dependent on an investigator's choices. Two reasons are identified: using anisotropy of a covariance matrix as evidence of preferential distribution of variability; and using orthogonality to quantify relevance of variability to task performance. Both are exquisitely sensitive to coordinates. Unless coordinates are known a priori, these methods do not support unambiguous inferences about CNS control. An alternative method uses a two-level approach where variability in task execution (expressed in one coordinate frame) is mapped by a function to its result (expressed in another coordinate frame). An analysis of variability in execution using this function to quantify performance at the level of results offers substantially less sensitivity to coordinates than analysis of a covariance matrix of execution variables. This is an initial step towards developing coordinate-invariant analysis methods for movement neuroscience.

Sternad, Dagmar; Park, Se-Woong; Muller, Hermann; Hogan, Neville

2010-01-01

302

Graphing and the Coordinate Plane  

NSDL National Science Digital Library

This lesson is designed to introduce students to graphing coordinates and lines in the Cartesian coordinate plane. This lesson provides links to discussions and activities related to graphing as well as suggested ways to integrate them into the lesson. Finally, the lesson provides links to follow-up lessons designed for use in succession with the current one.

2010-01-01

303

Chameleon Graphing: The Coordinate Plane  

NSDL National Science Digital Library

This Web unit introduces the coordinate plane with the help of Sam the Chameleon, who illustrates how to find points on a number line and graph points in the coordinate plane. A link to a Java applet for graphing with Sam is included.

Whitcher, Ursula

2000-01-01

304

Determination and correlation of solubilities of famotidine in water + co-solvent mixed solvents  

Microsoft Academic Search

This study aims to measure the solubilities of poorly water-soluble drugs and to enhance their solubilities by adding co-solvents. The solubilities were measured using high-performance liquid chromatography (HPLC). We selected famotidine, a histamine H2-receptor antagonist, as the pharmaceutical compound. We measured the solubilities of famotidine at 298.15K in five water\\/co-solvent mixed solvents, that is, two water+liquid co-solvent mixtures: water+ethanol, and

Hiroyuki Matsuda; Sho Matsumoto; Kenta Kaguragi; Kiyofumi Kurihara; Katsumi Tochigi; Kazuo Tomono

2011-01-01

305

Effect of organic solvents on the yield of solvent-tolerant Pseudomonas putida S12  

Microsoft Academic Search

Solvent-tolerant microorganisms are useful in biotransformations with whole cells in two-phase solvent- water systems. The results presented here describe the effects that organic solvents have on the growth of these organisms. The maximal growth rate of Pseudomonas putida S12, 0.8 h 21 , was not affected by toluene in batch cultures, but in chemostat cultures the solvent decreased the maximal

SONJA ISKEN; ANTOINE DERKS; PETRA F. G. WOLFFS; Bont de J. A. M

1999-01-01

306

Preparation of mesoporous silica films on a glass slide: surfactant template removal by solvent extraction  

Microsoft Academic Search

Mesoporous silica films have been deposited on glass slides by the dip-coating method. Solvent extraction was used to completely remove the structure-directing surfactant with a carefully selected dilute HCl\\/EtOH solution, which was confirmed by Fourier-Transform infrared spectroscopy (FT-IR), and the films' ordered mesostructure was maintained. The weak bonding between template ions and inorganic species of thin film materials also resulted

Zi-Le Hua; Jian-Lin Shi; Lin Wang; Wen-Hua Zhang

2001-01-01

307

Novel solvent-resistant hydrophilic hollow fiber membranes for efficient membrane solvent back extraction  

Microsoft Academic Search

The advantages of employing hydrophilic hollow fiber membranes for efficient membrane solvent back extraction are explored via novel solvent-resistant hydrophilic hollow fiber membranes. The mass transfer rate of solute in membrane-based solvent extraction is controlled by boundary layer resistances and the membrane resistance. The membrane resistance can be reduced by preferentially filling the membrane pores with the phase preferred by

P. B. Kosaraju; K. K. Sirkar

2007-01-01

308

Recycling of solvent used in a solvent extraction of petroleum hydrocarbons contaminated soil  

Microsoft Academic Search

The application of water washing technology for recycling an organic composite solvent consisting of hexane and pentane (4:1; TU-A solvent) was investigated for extracting total petroleum hydrocarbons (TPH) from contaminated soil. The effects of water volume, water temperature, washing time and initial concentration of solvent were evaluated using orthogonal experiments followed by single factor experiments. Our results showed that the

Guozhong Wu; Xingang Li; Frédéric Coulon; Hong Li; Jingyan Lian; Hong Sui

2011-01-01

309

Health sector development: from aid coordination to resource management.  

PubMed

Aid coordination has assumed a prominent place on health policy agendas. This paper synthesizes the findings of research undertaken to explore the changing practices of aid coordination across a number of countries. It begins by reviewing the key issues giving rise to increased attention to aid coordination in the health sector. The second section describes, assesses and compares the strengths and weaknesses of the dominant mechanisms or instruments which were found to be employed to coordinate health sector aid in the case studies. From this analysis, four factors become clear. First, in many countries, coordination mechanisms have been introduced as a part of an incremental process of trying out different approaches--there is no one model that stands out at any one time. Secondly, some instruments function largely for consultation, predominantly coordinating inputs, while others are more directive and operational, and are used to manage inputs, processes and outputs. Third, many of the mechanisms have not excelled, although, fourth, it is difficult to judge the effectiveness or impact of aid coordination. It is therefore argued that concern with the effectiveness of aid coordination arrangements must give way to a broader analysis of the processes, outputs and outcomes governing the use of both external and domestic resources, focusing on institutional characteristics, the distribution and nature of influence among the actors, and the interests which they pursue through the aid regime. These factors varied considerably across the countries indicating that aid management is context dependent and subject to continuing changes. Finally, the paper looks at the findings in the light of the introduction of sector-wide approaches. PMID:10621238

Walt, G; Pavignani, E; Gilson, L; Buse, K

1999-09-01

310

Weak {}^* convergence of operator means  

NASA Astrophysics Data System (ADS)

For a linear operator U with \\Vert U^n\\Vert \\le \\operatorname{const} on a Banach space X we discuss conditions for the convergence of ergodic operator nets T_\\alpha corresponding to the adjoint operator U^* of U in the {W^*O}-topology of the space \\operatorname{End} X^*. The accumulation points of all possible nets of this kind form a compact convex set L in \\operatorname{End} X^*, which is the kernel of the operator semigroup G=\\overline{\\operatorname{co}}\\,\\Gamma_0, where \\Gamma_0=\\{U_n^*, n \\ge 0\\}. It is proved that all ergodic nets T_\\alpha weakly {}^* converge if and only if the kernel L consists of a single element. In the case of X=C(\\Omega) and the shift operator U generated by a continuous transformation \\varphi of a metrizable compactum \\Omega we trace the relationships among the ergodic properties of U, the structure of the operator semigroups L, G and \\Gamma=\\overline{\\Gamma}_0, and the dynamical characteristics of the semi-cascade (\\varphi,\\Omega). In particular, if \\operatorname{card}L=1, then a) for any \\omega \\in\\Omega the closure of the trajectory \\{\\varphi^n\\omega, n \\ge 0\\} contains precisely one minimal set m, and b) the restriction (\\varphi,m) is strictly ergodic. Condition a) implies the {W^*O}-convergence of any ergodic sequence of operators T_n \\in \\operatorname{End} X^* under the additional assumption that the kernel of the enveloping semigroup E(\\varphi,\\Omega) contains elements obtained from the `basis' family of transformations \\{\\varphi^n, n \\ge 0\\} of the compact set \\Omega by using some transfinite sequence of sequential passages to the limit.

Romanov, Alexandr V.

2011-12-01

311

Classical field approach to quantum weak measurements.  

PubMed

By generalizing the quantum weak measurement protocol to the case of quantum fields, we show that weak measurements probe an effective classical background field that describes the average field configuration in the spacetime region between pre- and postselection boundary conditions. The classical field is itself a weak value of the corresponding quantum field operator and satisfies equations of motion that extremize an effective action. Weak measurements perturb this effective action, producing measurable changes to the classical field dynamics. As such, weakly measured effects always correspond to an effective classical field. This general result explains why these effects appear to be robust for pre- and postselected ensembles, and why they can also be measured using classical field techniques that are not weak for individual excitations of the field. PMID:24702338

Dressel, Justin; Bliokh, Konstantin Y; Nori, Franco

2014-03-21

312

Structure of the polymer-solvent interface  

NASA Technical Reports Server (NTRS)

The first measurements of ellipticities from the liquid-liquid interface between polymer and solvent mixtures near their consolute points are reported. When scaled according to theory the ellipticities of high molecular weight polystyrene + solvent mixtures are consistent with those from simple, low molecular weight mixtures. The universal value of the scaled ellipticity is approximately 20 percent lower than that predicted by present theories.

Miles, Danny G., Jr.; Schmidt, James W.

1990-01-01

313

REMEDIATION OF CONTAMINATED SOILS BY SOLVENT FLUSHING  

EPA Science Inventory

Solvent flushing is a potential technique for remediating a waste disposal/spill site contaminated with organic chemicals. his technique involves the injection of a solvent mixture (e.g., water plus alcohols) that enhances contaminant solubility, reduces the retardation factor, a...

314

REMEDIATION OF CONTAMINATED SOILS BY SOLVENT FLUSHING  

EPA Science Inventory

Solvent flushing is a potential technique for remediating a waste disposal/spill site contaminated with organic chemicals. This technique involves the injection of a solvent mixture (e.g., water plus alcohols) that enhances contaminant solubility, reduces the retardation factor, ...

315

SCENARIOS EVALUATION TOOL FOR CHLORINATED SOLVENT MNA  

Microsoft Academic Search

Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the

K Vangelas; Michael J. Truex; Charles J. Newell

2006-01-01

316

Separation of Tributyl Phosphate from Degraded Solvents.  

National Technical Information Service (NTIS)

A solvent extraction method is described for the recovery of tributyl phosphate (TBP) from degraded process solvents. The method involves the separation of TBP and shell solT(SST) from 30% TBP/SSP mixture by thorium nitrate extraction leading to the forma...

S. V. Kumar M. N. Nadkarni A. Ramanujam M. Venkatesan V. Gopalakrishnan

1977-01-01

317

SAFETY OF ORGANIC SOLVENTS IN WASTE TANKS  

SciTech Connect

This report addresses flash points and flammability limits of flammable gases found in waste tanks, primarily hydrocarbon mixtures derived from waste solvents. The effect of vapor pressure is discussed. Particular attention is given to Purex solvent. The pertinent facts are then applied to the safety of the waste tanks of concern.

Van Tuyl, H. H.

1983-08-01

318

Controlled solvent vapour annealing for polymer electronics  

Microsoft Academic Search

Solvent vapour annealing (SVA) is demonstrated as an attractive method to anneal polymer blend and block copolymer thin films at low temperatures. It is especially suitable for organic electronics, where sensitive materials with strong intermolecular interactions are used. We demonstrate the effect of solvent vapour exposure on the film properties of a perylene bisimide acrylate (PPerAcr) side-chain polymer with strong

Sven Hüttner; Michael Sommer; Arnaud Chiche; Georg Krausch; Ullrich Steiner; Mukundan Thelakkat

2009-01-01

319

SOLVENT USE EMISSIONS ESTIMATION METHODOLOGIES: FUTURE IMPLICATIONS  

EPA Science Inventory

The paper reviews uses of emissions data from solvent use activities and evaluates how the Clean Air Act Amendments of 1990 (CAAA) will affect future solvent use emissions estimation methodologies. Results of this work will be used to identify research opportunities and in planni...

320

Occupational chronic exposure to organic solvents  

Microsoft Academic Search

Four female assistants using a mixture of xylenes and ethylbenzeneas solvent in a histology laboratory were examined according to the concentrations of solvents in blood and the excretion of phenolic compounds in urine during 24 h. The average concentrations of (m+p)-xylene and ethylbenzene in air were between 56 and 68 ppm and 34 and 41 ppm respectively. It is shown

J. Angerer; G. Lehnert

1979-01-01

321

Intermolecular Forces and Solvent Effects. III  

Microsoft Academic Search

The shifts of frequency of two vibration bands of carbon dioxide in different solvents have been measured. The results cannot be explained satisfactorily in terms of the simple model of an oscillator in a continuous dielectric medium, but suggest that intermolecular forces are dominant. In non-polar solvents dispersion forces appear to account very well for the observed shifts, and attempts

C. Heald; H. W. Thompson

1962-01-01

322

ENHANCED PROCESSING OF GREEN SOLVENTS - PHASE I  

EPA Science Inventory

Solvents are a valuable processing tool in the chemical and related industries. Solvents are used to enhance mass transfer, heat transfer and in most cases are a processing aid and eventually are not used in the final product but to enhance the fabrication of the final pr...

323

Nuclear Magnetic Resonance in Liquid Crystal Solvents  

Microsoft Academic Search

Since the discovery by Saupe and Englert that a nematic phase is a satisfactory solvent for high resolution nuclear magnetic resonance (NMR) studies, the variety of liquid crystal phases which have been found useful in NMR experiments has greatly increased. The resonance studies have increased our understanding of the structure of the solvent mesophases, and of their interactions with solute

Lawrence C. Snyder; Saul Meiboom

1969-01-01

324

Solvent Extractions of Illinois No. 6 Coal.  

National Technical Information Service (NTIS)

The usual abilities of amine solvents, especially EDA, were recognized many years ago. Some recent work has dealt with solvents mixtures. What we think is new is the idea that amines have a chemical as well as a physical action and the finding that DMSO a...

F. R. Mayo L. A. Pavelka J. S. Zevely

1979-01-01

325

Cosmology from weak lensing of CMB  

NASA Astrophysics Data System (ADS)

The weak lensing effect on the cosmic microwave background (CMB) induces distortions in the spatial pattern of CMB anisotropies, and statistical properties of CMB anisotropies become a weakly non-Gaussian field. We first summarize the weak lensing effect on the CMB (CMB lensing) in the presence of scalar, vector, and tensor perturbations. Then we focus on the lensing effect on CMB statistics and methods to estimate deflection angles and their power spectrum. We end by summarizing recent observational progress and future prospects.

Namikawa, Toshiya

2014-06-01

326

Spin effects in the weak interaction  

SciTech Connect

Modern experiments investigating the beta decay of the neutron and light nuclei are still providing important constraints on the theory of the weak interaction. Beta decay experiments are yielding more precise values for allowed and induced weak coupling constants and putting constraints on possible extensions to the standard electroweak model. Here we emphasize the implications of recent experiments to pin down the strengths of the weak vector and axial vector couplings of the nucleon.

Freedman, S.J. (Argonne National Lab., IL (USA) Chicago Univ., IL (USA). Dept. of Physics Chicago Univ., IL (USA). Enrico Fermi Inst.)

1990-01-01

327

Toxic hepatitis in occupational exposure to solvents  

PubMed Central

The liver is the main organ responsible for the metabolism of drugs and toxic chemicals, and so is the primary target organ for many organic solvents. Work activities with hepatotoxins exposures are numerous and, moreover, organic solvents are used in various industrial processes. Organic solvents used in different industrial processes may be associated with hepatotoxicity. Several factors contribute to liver toxicity; among these are: species differences, nutritional condition, genetic factors, interaction with medications in use, alcohol abuse and interaction, and age. This review addresses the mechanisms of hepatotoxicity. The main pathogenic mechanisms responsible for functional and organic damage caused by solvents are: inflammation, dysfunction of cytochrome P450, mitochondrial dysfunction and oxidative stress. The health impact of exposure to solvents in the workplace remains an interesting and worrying question for professional health work.

Malaguarnera, Giulia; Cataudella, Emanuela; Giordano, Maria; Nunnari, Giuseppe; Chisari, Giuseppe; Malaguarnera, Mariano

2012-01-01

328

Thermoplastic composite matrices with improved solvent resistance  

NASA Technical Reports Server (NTRS)

In order to improve solvent resistance of aromatic thermoplastic polymers, ethynyl-terminated aromatic sulfone polymers (ETS), sulfone/ester polymers (SEPE) containing pendent ethynyl groups, and phenoxy resin containing pendent ethynyl groups are synthesized. Cured polysulfones and phenoxy resins containing ethynyl groups on the ends or pendent on the molecules exhibited systematic behavior in solvent resistance, film flexibility, and toughness as a function of crosslink density. The film and composite properties of a cured solvent-resistant ETS were better than those of a commercially available solvent sensitive polysulfone. The study was part of a NASA program to better understand the trade-offs between solvent resistance, processability and mechanical properties which may be useful in designing composite structures for aerospace vehicles.

Hergenrother, P. M.; Jensen, B. J.; Havens, S. J.

1984-01-01

329

Organic solvent regeneration of granular activated carbon  

NASA Astrophysics Data System (ADS)

The use of activated carbon for the treatment of industrial waste-streams was shown to be an effective treatment. The high costs associated with the replacement or thermal regeneration of the carbon have prohibited the economic feasibility of this process. The in situ solvent regeneration of activated carbon by means of organic solvent extraction was suggested as an economically alternative to thermal regeneration. The important aspects of the solvent regeneration process include: the physical and chemical characteristics of the adsorbent, the pore size distribution and energy of adsorption associated with the activated carbon; the degree of solubility of the adsorbate in the organic solvent; the miscibility of the organic solvent in water; and the temperature at which the generation is performed.

Cross, W. H.; Suidan, M. T.; Roller, M. A.; Kim, B. R.; Gould, J. P.

1982-09-01

330

Synthesis, structure and spectroscopic properties of two new trinuclear nickel(II) clusters possessing solvent effect  

NASA Astrophysics Data System (ADS)

Two solvent-induced trinuclear nickel(II) clusters, [{NiL(CH 3OH)} 2(OAc) 2Ni]·2CH 3OH ( I) and [{NiL(C 2H 5OH)} 2(OAc) 2Ni]·2C 2H 5OH ( II), have been synthesized by the reaction of a new Salen-type bisoxime chelating ligand of 5,5'-di( N, N'-diethylamino)-2,2'-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol (H 2L) with nickel(II) acetate tetrahydrate in different solvents. Clusters I and II were characterized by elemental analyses, IR spectra, UV-vis absorption spectra, TG-DTA and X-ray diffraction methods. In clusters I (or II), there are two ligand moieties (which provide N 2O 2 donors), two acetate ions, two coordinated methanol (or ethanol) molecules and two crystallizing methanol (or ethanol) molecules, which result in the formation of three slightly distorted octahedral geometries around Ni(II) ions. Interestingly, nickel(II) ions in the structures of clusters I and II are all six-coordinated geometry, but clusters I and II are grown up in different solvent. Right because of this, solvent effect cause to their different crystal structures.

Dong, Wen-Kui; Chen, Xiao; Sun, Yin-Xia; Yang, Yu-Hua; Zhao, Li; Xu, Li; Yu, Tian-Zhi

2009-10-01

331

Underwater communication using weakly dispersive modal pulses  

NASA Astrophysics Data System (ADS)

In the modal description of sound propagation, signal distortion is caused primarily by dispersion, which is largely controlled by the product I( m; f)?( m; f). Here m is mode number, f is acoustic frequency, I is the action and ? is the waveguide invariant. A modal pulse with fixed m and variable f that satisfies I? ? 0 over the entire frequency band is referred to in this letter as a weakly dispersive modal pulse. The manner by which weakly dispersive modal pulses can be exploited in underwater communications applications is described and illustrated. The connection between weakly dispersive modal pulses and weakly divergent beams is discussed.

Brown, Michael G.; Udovydchenkov, Ilya A.

2013-09-01

332

Weak localization in monolayer and bilayer graphene  

NASA Astrophysics Data System (ADS)

We describe the weak localization correction to conductivity in ultra-thin graphene films, taking into account disorder scattering and the influence of trigonal warping of the Fermi surface. A possible manifestation of the chiral nature of electrons in the localization properties is hampered by trigonal warping, resulting in a suppression of the weak anti-localization effect in monolayer graphene and of weak localization in bilayer graphene. Intervalley scattering due to atomically sharp scatterers in a realistic graphene sheet or by edges in a narrow wire tends to restore weak localization resulting in negative magnetoresistance in both materials.

Kechedzhi, K.; McCann, E.; Fal'Ko, V. I.; Suzuura, H.; Ando, T.; Altshuler, B. L.

2007-09-01

333

Solvent effect on testosterone-antitestosterone interaction.  

PubMed

The inhibition of the binding between testosterone and antitestosterone antiserum caused by organic solvents was studied at pH 7.4, 298 K. Inhibition curves were obtained at variable ranges of molar fractions for the following solvents: methanol (range 0-0.4), ethanol (0-0.317), 1-propanol (0-0.082), 2-propan-ol (0-0.260), t-butanol (0-0.223), ethylenglycol (0-0.189), 2-methoxyethanol (0.036), 2-butoxyethanol (0-0.063), 1,4-dioxan (0-0.124), tetrahydrofuran (0-0.238) and acetonitrile (0-0.392). Steroid-antibody binding decreases with increasing molar fraction of solvent in the reaction mixture for all but tetrahydrofuran and acetonitrile, which enhance binding at low molar fraction then cause a sharp inhibition. Molar fraction of solvent that causes a 50% binding inhibition is uncorrelated to some solvent properties (i.e. dielectric constant, polarity index, dipole moment) but is inversely correlated to the molecular mass of the solvent. The correlation becomes better by taking into account the length of the solvent molecule, or the Randic molecular connectivity index, suggesting that binding inhibition could be related to the length of the solvent molecules that displace water around the steroid molecule. However, the increase of binding observed at low molar fraction with tetrahydrofuran and acetonitrile, together with very different shapes of inhibition curves suggest that a molecular mechanism based on the differential solvation of the steroid by solvent and water molecules must be taken into account to explain adequately the solvent effect on testosterone-antitestosterone interaction. PMID:8507658

Giraudi, G; Baggiani, C

1993-06-11

334

Organic solvents used in enterprises of various sizes  

Microsoft Academic Search

This study was initiated to examine prevalent types of solvent used and the relative risk of high solvent exposure by types of solvent work. Air samples were collected in 1010 solvent workplaces (SWPs) (?5 samples\\/SWP) in 156 enterprises of various sizes and analyzed for 47 organic solvents. The geometric mean values of the concentrations in the ?5 samples were taken

J. Moriguchi; H. Samoto; Y. Fukui; H. Ukai; S. Okamoto; S. Takada; F. Ohashi; T. Ezaki; M. Ikeda

2006-01-01

335

Binding weakly interacting partners: a study of Ca-He2 and its isotopomers  

NASA Astrophysics Data System (ADS)

We present in this paper binding energies and structures of non-rotating weakly bound 40Ca- n He2 triatomic complexes. Two kind of systems are discussed: bosonic ( n = 4) and fermionic ( n = 3) complexes at its singlet state (nuclear spin S = 0). Three different coordinate systems and methods have been used to solve the relevant Schrödinger equation: variational calculations (1) using satellite coordinates and a discrete variable representation of radial functions; (2) employing pair coordinates and products of distributed Gaussian functions as basis functions; and (3) variational/Diffusion Monte Carlo calculations in Cartesian coordinates. The potential energy surface is represented as the addition of pair potentials. By using the most realistic interaction between each pair of particles, present results from the three methods are in fair agreement. Only two bound states for each system are found in our computations.

López-Durán, D.; Rodríguez-Cantano, R.; González-Lezana, T.; Delgado-Barrio, G.; Villarreal, P.; Gianturco, F. A.

2012-07-01

336

Specific binding of ethanol to cholesterol in organic solvents.  

PubMed Central

Although ethanol has been reported to affect cholesterol homeostasis in biological membranes, the molecular mechanism of action is unknown. Here, nuclear magnetic resonance (NMR) spectroscopic techniques have been used to investigate possible direct interactions between ethanol and cholesterol in various low dielectric solvents (acetone, methanol, isopropanol, DMF, DMSO, chloroform, and CCl(4)). Measurement of (13)C chemical shifts, spin-lattice and multiplet relaxation times, as well as self-diffusion coefficients, indicates that ethanol interacts weakly, yet specifically, with the HC-OH moiety and the two flanking methylenes in the cyclohexanol ring of cholesterol. This interaction is most strong in the least polar-solvent carbon tetrachloride where the ethanol-cholesterol equilibrium dissociation constant is estimated to be 2 x 10(-3) M. (13)C-NMR spin-lattice relaxation studies allow insight into the geometry of this complex, which is best modeled with the methyl group of ethanol sandwiched between the two methylenes in the cyclohexanol ring and the hydroxyl group of ethanol hydrogen bonded to the hydroxyl group of cholesterol.

Daragan, V A; Voloshin, A M; Chochina, S V; Khazanovich, T N; Wood, W G; Avdulov, N A; Mayo, K H

2000-01-01

337

AN ACCELERATED RATE CALORIMETRY STUDY OF CAUSTIC-SIDE SOLVENT EXTRACTION SOLVENT WITHOUT EXTRACTANT  

SciTech Connect

This study found that 4 - 48 part per thousand (ppth) of Caustic Side Solvent Extraction (CSSX) solvent without extractant in caustic salt solution at evaporator-relevant temperatures result in no process-significant energetic events. However, the data suggest a chemical reaction (possible decomposition) in the CSSX solvent near 140 C. This concentration of entrained solvent is believed to markedly exceed the amount of solvent that will pass from the Modular Caustic Side Solvent Unit (MCU) through the downstream Defense Waste Processing Facility and enter the evaporator through routine tank farm operations. The rate of pressure rise at 140 C differs appreciably - i.e., is reduced - for salt solution containing the organic from that of the same solution without solvent. This behavior is due to a reaction between the CSSX components and the salt solution simulant.

Fondeur, F; Samuel Fink, S

2006-03-07

338

40 CFR Table 3 to Subpart Nnnn of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2012-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent...to Subpart NNNN of Part 63âDefault Organic HAP Mass Fraction for Solvents and Solvent...solvent blend CAS. No. Average organic HAP mass fraction Typical organic...

2013-07-01

339

40 CFR Table 3 to Subpart Rrrr of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2012-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent...to Subpart RRRR of Part 63âDefault Organic HAP Mass Fraction for Solvents and Solvent...Solvent blend CAS. No. Average organic HAP mass fraction Typical organic...

2013-07-01

340

40 CFR Table 5 to Subpart Qqqq of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2012-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent...to Subpart QQQQ of Part 63âDefault Organic HAP Mass Fraction for Solvents and Solvent...solvent blend CAS. No. Average organic HAP mass fraction Typical organic...

2013-07-01

341

40 CFR Table 5 to Subpart Vvvv of... - Default Organic HAP Contents of Solvents and Solvent Blends  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2012-07-01 true Default Organic HAP Contents of Solvents and Solvent Blends...to Subpart VVVV of Part 63âDefault Organic HAP Contents of Solvents and Solvent Blends...63.5758(a)(6), when detailed organic HAP content data for solvent blends...

2013-07-01

342

Solvent effects on the ultrafast dynamics and spectroscopy of the charge-transfer-to-solvent reaction of sodide  

Microsoft Academic Search

In ``outer sphere'' electron transfer reactions, motions of the solvent molecules surrounding the donor and acceptor govern the dynamics of charge flow. Are the relevant solvent motions determined simply by bulk solvent properties such as dielectric constant or viscosity? Or are molecular details, such as the local solvent structure around the donor and acceptor, necessary to understand how solvent motions

Erik R. Barthel; Ignacio B. Martini; Erno Keszei; Benjamin J. Schwartz

2003-01-01

343

Solvent effects on the ultrafast dynamics and spectroscopy of the charge-transfer-to-solvent reaction of sodide  

Microsoft Academic Search

In “outer sphere” electron transfer reactions, motions of the solvent molecules surrounding the donor and acceptor govern the dynamics of charge flow. Are the relevant solvent motions determined simply by bulk solvent properties such as dielectric constant or viscosity? Or are molecular details, such as the local solvent structure around the donor and acceptor, necessary to understand how solvent motions

Erik R. Barthel; Ignacio B. Martini; Benjamin J. Schwartz

2003-01-01

344

Solvent effects on the ultrafast dynamics and spectroscopy of the charge-transfer-to-solvent reaction of sodide  

Microsoft Academic Search

In ''outer sphere'' electron transfer reactions, motions of the solvent molecules surrounding the donor and acceptor govern the dynamics of charge flow. Are the relevant solvent motions determined simply by bulk solvent properties such as dielectric constant or viscosity? Or are molecular details, such as the local solvent structure around the donor and acceptor, necessary to understand how solvent motions

Benjamin J. Schwartza

345

Markov Tracking for Agent Coordination  

NASA Technical Reports Server (NTRS)

Partially observable Markov decision processes (POMDPs) axe an attractive representation for representing agent behavior, since they capture uncertainty in both the agent's state and its actions. However, finding an optimal policy for POMDPs in general is computationally difficult. In this paper we present Markov Tracking, a restricted problem of coordinating actions with an agent or process represented as a POMDP Because the actions coordinate with the agent rather than influence its behavior, the optimal solution to this problem can be computed locally and quickly. We also demonstrate the use of the technique on sequential POMDPs, which can be used to model a behavior that follows a linear, acyclic trajectory through a series of states. By imposing a "windowing" restriction that restricts the number of possible alternatives considered at any moment to a fixed size, a coordinating action can be calculated in constant time, making this amenable to coordination with complex agents.

Washington, Richard; Lau, Sonie (Technical Monitor)

1998-01-01

346

Technique for Coordinating Autonomous Robots.  

National Technical Information Service (NTIS)

This paper describes a technique for coordinating the subsystems of autonomous robots which takes advantage of a distributed blackboard mechanism and a high degree of functional distribution between subsystems to minimize communications and simplify the i...

S. Y. Harmon, W. A. Aviles, D. W. Gage

1986-01-01

347

Central African Industrial Coordination Survey.  

National Technical Information Service (NTIS)

The report presents the findings and conclusions of an Industrial Coordination Survey of the Central African sub-region of Cameroun, Central African Republic, Chad, Congo, Democratic Republic of the Congo (Zaire), and Gabon. The principle objective of the...

R. Manly

1965-01-01

348

Sensory Coordination of Insect Flight.  

National Technical Information Service (NTIS)

This report contains the investigation results to the following questions: 1) Antennal positioning behavior in the moth, Daphnis neerii, 2) Location of odor sources in the fruit fly, Drosophila melanogaster, 3) Wing- haltere coordination in the soldier fl...

S. Sane

2010-01-01

349

Marketing Coordination in Agricultural Cooperatives.  

National Technical Information Service (NTIS)

The use of marketing agreements adds elements of marketing coordination between members and their cooperatives. Marketing agreements used in this study included both marketing contracts signed with members and bylaw provisions that required members to mar...

R. A. Wissman

1999-01-01

350

Creating Interorganizational Coordination: Project Report.  

National Technical Information Service (NTIS)

The report describes a research utilization effort designed to synthesize the existing research knowledge about Interorganizational Coordination and to develop preliminary training and orientation materials that could be used to teach relevant personnel h...

G. E. Klonglan C. L. Mulford R. D. Warren J. M. Winkelpleck

1975-01-01

351

Unusual effects of solvent polarity on capacitance for organic electrolytes in a nanoporous electrode  

NASA Astrophysics Data System (ADS)

The interplay between ions and solvent molecules inside the nanoporous electrodes of a supercapacitor has not been well understood but could be a fertile ground for new insights into the device's performance. By tuning the dipole moment of the solvent in an organic electrolyte, we find, from classical density functional theory calculations, pronounced oscillation of capacitance with the pore size for a moderately to weakly polar solvent. A quantitative analysis of the electric-double-layer (EDL) structure indicates that the capacitance oscillation shares a similar physical origin to that of an ionic liquid electrolyte: the oscillatory behavior arises from the formation of alternating layers of counterions and coions near strongly charged surfaces. More interestingly, we find that in the large-pore region, the capacitance versus the pore size has a volcano-shaped trend; in other words, there exists a solvent dipole moment that yields a maximal capacitance. These theoretical predictions can be validated with future experiments and highlight the great potential in tuning the organic solvent to achieve optimal performance of EDL capacitors.

Jiang, De-En; Wu, Jianzhong

2014-04-01

352

Ten years of probabilistic estimates of biocrystal solvent content: new insights via nonparametric kernel density estimate.  

PubMed

The probabilistic estimate of the solvent content (Matthews probability) was first introduced in 2003. Given that the Matthews probability is based on prior information, revisiting the empirical foundation of this widely used solvent-content estimate is appropriate. The parameter set for the original Matthews probability distribution function employed in MATTPROB has been updated after ten years of rapid PDB growth. A new nonparametric kernel density estimator has been implemented to calculate the Matthews probabilities directly from empirical solvent-content data, thus avoiding the need to revise the multiple parameters of the original binned empirical fit function. The influence and dependency of other possible parameters determining the solvent content of protein crystals have been examined. Detailed analysis showed that resolution is the primary and dominating model parameter correlated with solvent content. Modifications of protein specific density for low molecular weight have no practical effect, and there is no correlation with oligomerization state. A weak, and in practice irrelevant, dependency on symmetry and molecular weight is present, but cannot be satisfactorily explained by simple linear or categorical models. The Bayesian argument that the observed resolution represents only a lower limit for the true diffraction potential of the crystal is maintained. The new kernel density estimator is implemented as the primary option in the MATTPROB web application at http://www.ruppweb.org/mattprob/. PMID:24914969

Weichenberger, Christian X; Rupp, Bernhard

2014-06-01

353

Unusual effects of solvent polarity on capacitance for organic electrolytes in a nanoporous electrode.  

PubMed

The interplay between ions and solvent molecules inside the nanoporous electrodes of a supercapacitor has not been well understood but could be a fertile ground for new insights into the device's performance. By tuning the dipole moment of the solvent in an organic electrolyte, we find, from classical density functional theory calculations, pronounced oscillation of capacitance with the pore size for a moderately to weakly polar solvent. A quantitative analysis of the electric-double-layer (EDL) structure indicates that the capacitance oscillation shares a similar physical origin to that of an ionic liquid electrolyte: the oscillatory behavior arises from the formation of alternating layers of counterions and coions near strongly charged surfaces. More interestingly, we find that in the large-pore region, the capacitance versus the pore size has a volcano-shaped trend; in other words, there exists a solvent dipole moment that yields a maximal capacitance. These theoretical predictions can be validated with future experiments and highlight the great potential in tuning the organic solvent to achieve optimal performance of EDL capacitors. PMID:24733527

Jiang, De-en; Wu, Jianzhong

2014-05-21

354

Vibrational spectra of 2-methylpropanal: Assignments, self-associations and solvent effects  

NASA Astrophysics Data System (ADS)

Raman and infrared spectra of 2-methylpropanal (CH 3) 2CHCHO, (CH 3) 2CDCHO and (CH 3) 2CHCDO in different physical states (liquid, solid and solution) have been investigated between 4000 and 40 cm -1. A complete assignment is carried out on the basis of one predominant conformer (anticlinal) in equilibrium with another less stable one (synperiplanar). Some vibrational modes of the synperiplanar form are identified. The CO stretching region is carefully examined. The complex structure of this band as a function of the physical state of the pure aldehyde and the polarity of the solvent for solutions is discussed. The structure can be explained by Fermi resonances between combinations and the fundamental ?CO mode. In the pure liquid, as well as in solution, the broadness of the band can be due to random dipolar interactions. In polar basic solvents (CH 3CN and DMSO), these interactions implicate both aldehyde and solvent. When the solvent is slightly acidic (HCCl 3), weak hydrogen bonds between the aldehydic group and the solvent may occur. Moving from the liquid to the solid state, in addition to the fact that the less stable conformer disappears, molecular association between the CO groups by charge transfer may account for the observed changes.

Piart-Goypiron, A.; Baron, M. H.; Belloc, J.; Coulange, M. J.; Zine, H.

355

Organic Solvent Tolerant Lipases and Applications  

PubMed Central

Lipases are a group of enzymes naturally endowed with the property of performing reactions in aqueous as well as organic solvents. The esterification reactions using lipase(s) could be performed in water-restricted organic media as organic solvent(s) not only improve(s) the solubility of substrate and reactant in reaction mixture but also permit(s) the reaction in the reverse direction, and often it is easy to recover the product in organic phase in two-phase equilibrium systems. The use of organic solvent tolerant lipase in organic media has exhibited many advantages: increased activity and stability, regiospecificity and stereoselectivity, higher solubility of substrate, ease of products recovery, and ability to shift the reaction equilibrium toward synthetic direction. Therefore the search for organic solvent tolerant enzymes has been an extensive area of research. A variety of fatty acid esters are now being produced commercially using immobilized lipase in nonaqueous solvents. This review describes the organic tolerance and industrial application of lipases. The main emphasis is to study the nature of organic solvent tolerant lipases. Also, the potential industrial applications that make lipases the biocatalysts of choice for the present and future have been presented.

Kanwar, Shamsher S.

2014-01-01

356

Environmental Impacts on Nuclear Reprocessing Solvents  

NASA Astrophysics Data System (ADS)

Nuclear tests have been employed ever since the first nuclear explosion in Alamogordo, NM during the mid-1940s. Nuclear weapons pose a threat to civil society and result in extensive biological (medical) damages. For this reason, treaties banning nuclear tests and weapons have been employed since the 1960s to cease proliferation of weapons. However, as nuclear tests continue in secrecy and actinides, such as plutonium and uranium, are eligible for theft, nuclear forensics is needed to prevent weapons proliferation. In this study, solvents [tributyl phosphate (TBP), dodecane, decanol] used in reprocessing spent nuclear fuel are analyzed using an isotope ratio mass spectrometer, which provides indisputable evidence in identifying the operation in which solvents were used. Solvent samples are observed under variable conditions in the laboratory for different time periods. It is assumed that their carbon isotope values (?13C) will become more positive (shift heavy) with time. It is found that the solvents are hygroscopic. TBP leaves the most robust signature compared to the other solvents studied and the isotope values for all solvents under all conditions become more positive with time. This study serves as primary research in understanding how solvents behave under variable conditions in the laboratory and how this could be translated to the environment in fate and transport studies.

Gillens, A. R.; Fessenden, J. E.

2009-12-01

357

Differential response of marine diatoms to solvents  

SciTech Connect

Unicellular algae in aquatic ecosystems are subjected to a variety of pollutants from sources such as runoff from agricultural lands and industrial outfalls. Organic solvents are natural components of oil deposits and commonly find their way into surface waters as a result of discharges from refineries, waste oil, disposal, and accidental spills. Organic solvents can make their way into the environment as industrial wastes. Because of their carcinogenic potential, contamination of soil and water by solvents is cause for serious concern. Relatively few reports have been published on the comparative toxicity of solvents towards test organisms, and these dealt primarily with fish and aquatic invertebrates. However, only few data of toxicity effects of solvents on algae have been published. Phytoplankton species vary in their tolerance to trace metals. Diatoms in particular are able to detoxify trace metals by the excretion of organic compounds. A previous study reported that diatoms collected form different sites in the Gulf of Mexico varied in their physiological characteristics. Algae have been considered to be good indicator s of bioactivity of industrial wastes. Unicellular algae vary in their response to a variety of toxicants. Little is known, however, about toxicity of solvents to marine diatoms. The work reported here was done to examine the effect of selected solvents on seven diatom species to determine whether they differed in their responses to these chemicals. 16 refs., 1 fig.

Tadros, M.G.; Phillips, J.; Patel, H.; Pandiripally, V. [Alabama A & M Univ., Huntsville, AL (United States)

1995-06-01

358

Organic solvent tolerant lipases and applications.  

PubMed

Lipases are a group of enzymes naturally endowed with the property of performing reactions in aqueous as well as organic solvents. The esterification reactions using lipase(s) could be performed in water-restricted organic media as organic solvent(s) not only improve(s) the solubility of substrate and reactant in reaction mixture but also permit(s) the reaction in the reverse direction, and often it is easy to recover the product in organic phase in two-phase equilibrium systems. The use of organic solvent tolerant lipase in organic media has exhibited many advantages: increased activity and stability, regiospecificity and stereoselectivity, higher solubility of substrate, ease of products recovery, and ability to shift the reaction equilibrium toward synthetic direction. Therefore the search for organic solvent tolerant enzymes has been an extensive area of research. A variety of fatty acid esters are now being produced commercially using immobilized lipase in nonaqueous solvents. This review describes the organic tolerance and industrial application of lipases. The main emphasis is to study the nature of organic solvent tolerant lipases. Also, the potential industrial applications that make lipases the biocatalysts of choice for the present and future have been presented. PMID:24672342

Sharma, Shivika; Kanwar, Shamsher S

2014-01-01

359

The Sloan Nearby Cluster Weak Lensing Survey  

Microsoft Academic Search

We describe and present initial results of a weak lensing survey of nearby (z lsim 0.1) galaxy clusters in the Sloan Digital Sky Survey (SDSS). In this first study, galaxy clusters are selected from the SDSS spectroscopic galaxy cluster catalogs of Miller et al. and Berlind et al. We report a total of seven individual low-redshift cluster weak lensing measurements

Jeffrey M. Kubo; James T. Annis; Frances Mei Hardin; Donna Kubik; Kelsey Lawhorn; Huan Lin; Liana Nicklaus; Dylan Nelson; Ribamar Rondon de Rezende Reis; Hee-Jong Seo; Marcelle Soares-Santos; Albert Stebbins; Tony Yunker

2009-01-01

360

Tests of the weak equivalence principle  

Microsoft Academic Search

The Einstein equivalence principle is the foundation for general relativity and all metric theories of gravity. Of its three tenets—the equality of acceleration of test bodies, or weak equivalence principle; the validity of Lorentz invariance in local freely falling frames; and the position invariance of local physical laws—the weak equivalence principle has played the most important role historically, and continues

C C Speake; C M Will

2012-01-01

361

Low-energy electro-weak reactions  

NASA Astrophysics Data System (ADS)

Chiral effective field theory (EFT) provides a systematic and controlled approach to low-energy nuclear physics. Here, we use chiral EFT to calculate low-energy weak Gamow-Teller transitions. We put special emphasis on the role of two-body (2b) weak currents within the nucleus, and discuss their applications in predicting physical observables.

Gazit, Doron

2013-10-01

362

AXAF Coordinate Transformation at XRCF  

NASA Technical Reports Server (NTRS)

Coordinate transformation between focal plane and detector pixel systems must be handled carefully at the X-ray Calibration Facility (XRCF) as it will be during flight. The High Resolution Mirror Assembly (HRMA) X-ray Detection System (HXDS) stage dithers, and the five-axis mount (FAM) attachment points underwent various types of motion during testing. At the XRCF when the FAM moved, the Science Instrument Module (SIM) travel direction was not necessarily aligned with the mirror axis motion, and, in addition, an arbitrary position offset had to be calibrated. Misalignment from the mirror axis was assessed by measuring its displacement from the boresight configuration of the default FAM frame, and the HXDS stage was monitored for motion from the default FAM reference point. Mirror position, prescribed in a mirror modal coordinate system, was measured in HRMA pitch and yaw axes. Prior to corrections for dithering and FAM movement, the coordinate data at XRCF also had to be corrected for possible misalignments of the mirror mount relative to XRCF and the default FAM axes due to the movement of the FAM feet. Those misalignments were processed in terms of yaw-pitch-roll Euler angles in the mirror nodal coordinate, and in the default FAM frame, respectively. An AXAF Science Center (ASC) coordinate library, pixlib, has been built to support these coordinate transformations and was used during x-ray calibration at the George C. Marshall Space Flight Center, Huntsville, AL. The design and implementation of this library will be discussed.

He, Helen; McDowell, Jonathan; Conroy, Maureen

1997-01-01

363

Effect of solvent characteristics on coal liquefaction  

SciTech Connect

It has been known for a long time that the characteristics of the liquefaction solvent has a profound effect on direct coal liquefaction. The amount of hydrogen consumed during the liquefaction process, the degree and quantity of retrograde reactions that occur, and the quality of the liquid products are all influenced by the process solvent. A number of analytical approaches have been developed to determine the important characteristics of the solvent for coal liquefaction. The hydrogen donor ability has clearly been important. However, such other characteristics of a liquefaction solvent as solubility parameter, content and type of higher aromatic hydrocarbons, and phenolic content have also been found to be significant. Finseth et al. have shown that the bulk of the hydrogen consumed from an uncatalyzed donor solvent liquefaction above 400{degrees}C is consumed in gas generation, heteroatom removal and hydrogenolysis of the coal matrix. Wilson et al. have also shown that the major role of hydrogen in uncatalyzed liquefaction is consumed by alkyl fission and hydrogenolysis reactions and not with hydrogenating aromatic rings. McMillan et al. have postulated that a radical hydrogen transfer process along with donor solvent capping of thermally produced radicals from the coal as possible processes involved with the hydroaromatic donor solvents in coal liquefaction. With the development of a short contact time batch reactor (SCTBR), determining the influence of the processing solvent on the liquefaction rates, conversion profiles and the quality of the liquid product at a particular time became possible. The influence of type of solvent, combined with other effects, such as gas atmosphere (i.e., in hydrogen and in nitrogen) and catalyst, on the coal liquefaction is reported in this paper.

Huang, He; Wang, Shaojie; Wang, Keyu; Klein, M.T.; Calkins, W.H. [Univ. of Delaware, Newark, DE (United States)

1996-12-31

364

End Use of Solvents Containing Volatile Organic Compounds.  

National Technical Information Service (NTIS)

Recently published information on production and end uses of individual solvents was reviewed. The information was supplemented through interviews with solvent producers and marketers. Information on solvent content of consumer products was obtained by a ...

N. Ostojic

1979-01-01

365

THE DESIGN OF TECHNOLOGICALLY EFFECTIVE AND ENVIRONMENTALLY BENIGN SOLVENT SUBSTITUTES  

EPA Science Inventory

There is presently considerable interest in finding environmentally benign replacement solvents that can perform in many different applications as solvents normally do. This requires solvents with desirable properties, e.g., ability to dissolve certain compounds, and without oth...

366

Fluoro-Carbonate Solvents for Li-Ion Cells.  

National Technical Information Service (NTIS)

A number of fluoro-carbonate solvents were evaluated as electrolytes for Li-ion cells. These solvents are fluorine analogs of the conventional electrolyte solvents such as dimethyl carbonate, ethylene carbonate, diethyl carbonate in Li-ion cells. Conducti...

Nagasubramanian

1999-01-01

367

The Bianchi identity and weak gravitational lensing  

NASA Astrophysics Data System (ADS)

We consider the Bianchi identity as a field equation for the distortion of the shapes of images produced by weak gravitational lensing. Using the spin coefficient formalism of Newman and Penrose (1962 J. Math. Phys. 3 566 78), we show that certain complex components of the Weyl and Ricci curvature tensors are directly related to fundamental observables in weak gravitational lensing. In the case of weak gravitational fields, we then show that the Bianchi identity provides a field equation for the Ricci tensor assuming a known Weyl tensor. From the Bianchi identity, we derive the integral equation for weak lensing presented by Miralda-Escude (1996 IAU Symp. vol 173 p 131), thus making the Bianchi identity a first principles equation of weak gravitational lensing. This equation is integrated in the important case of an axially symmetric lens and explicitly demonstrated in the case of a point lens and a singular isothermal sphere (SIS) model.

Kling, Thomas P.; Keith, Brian

2005-07-01

368

TRUEX process solvent cleanup with solid sorbents  

SciTech Connect

Solid sorbents, alumina, silica gel, and Amberlyst A-26 have been tested for the cleanup of degraded TRUEX-NPH solvent. A sodium carbonate scrub alone does not completely remove acidic degradation products from highly degraded solvent and cannot restore the stripping performance of the solvent. By following the carbonate scrub with either neutral alumina or Amberlyst A-26 anion exchange resin, the performance of the TRUEX-NPH is substantially restored. The degraded TRUEX-NPH was characterized before and after treatment by supercritical fluid chromatography. Its performance was evaluated by americium distribution ratios, phase-separation times, and lauric acid distribution coefficients. 17 refs., 2 figs., 5 tabs.

Tse, Pui-Kwan; Reichley-Yinger, L.; Vandegrift, G.F.

1989-01-01

369

Switchable solvents and methods of use thereof  

DOEpatents

A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

Jessop, Philip G.; Eckert, Charles A.; Liotta, Charles L.; Heldebrant, David J.

2013-08-20

370

Reduction of solvent emissions from vapor degreasing  

SciTech Connect

Hutchinson Tehnology, Inc. (HTI) implemented a number of low cost, low technology procedures to reduce emissions and prevent solvent loss from two open-top freon (CFC-113) vapor degreasers (Branson No. 1 and No. 2). HTI is a computer components manufacturer that uses freon vapor degreasing systems to remove fluxes and other residues remaining on the flexible printed circuits from the soldering process. With relatively minor changes in operation, solvent emissions were reduced by an average of 2.8 gallons per day (GDP) for both degreasers combined. It is anticipated that HTI will follow through with installation of an automatic cover, which can result in further solvent emissions reduction.

Buresh, P.

1989-12-31

371

Cleaning solvent substitution in electronic assemblies  

SciTech Connect

Alternatives to chlorinated and fluorinated solvents have been identified, qualified, and implemented into production of complex electronic assemblies. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, has been selected as the solvent of choice for cleaning complex electronic assemblies, and has been found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data.

Meier, G.J.

1993-09-01

372

Firing of pulverized solvent refined coal  

DOEpatents

A burner for the firing of pulverized solvent refined coal is constructed and operated such that the solvent refined coal can be fired successfully without any performance limitations and without the coking of the solvent refined coal on the burner components. The burner is provided with a tangential inlet of primary air and pulverized fuel, a vaned diffusion swirler for the mixture of primary air and fuel, a center water-cooled conical diffuser shielding the incoming fuel from the heat radiation from the flame and deflecting the primary air and fuel steam into the secondary air, and a watercooled annulus located between the primary air and secondary air flows.

Lennon, Dennis R. (Allentown, PA); Snedden, Richard B. (McKeesport, PA); Foster, Edward P. (Macungie, PA); Bellas, George T. (Library, PA)

1990-05-15

373

Tyrosinase inactivation in organic solvents.  

PubMed

The inactivation of the catecholase activity of mushroom tyrosinase was investigated under nonaqueous conditions. The enzyme was immobilized on glass beads, and assays were conducted in chloroform, toluene, amyl acetate, isopropyl ether, and butanol. The reaction components were pre-equilibrated for 2 weeks with a saturated salt solution at a water activity of 0.90. The initial reaction velocity varied between 1.3 x 10(3) mol product/((mol enzyme)(min)) in toluene and 8.7 x 10(3) mol product/((mol enzyme)(min)) in amyl acetate. The turnover number varied between 8.1 x 10(3) mol product/mol enzyme in toluene and 7.2 x 10(4) mol product/mol enzyme in amyl acetate. In each solvent, the tyrosinase reaction inactivation parameters were represented by a probabilistic model. Changes in the probability of inactivation were followed throughout the course of the reaction using a second model which relates the reaction velocity to the amount of product formed. These models reveal that the inactivation rate of tyrosinase decreases as the reaction progresses, and that the inactivation kinetics are independent of the quinone concentration in toluene, chloroform, butanol, and amyl acetate. Significant effects of quinone concentration were, however, observed in isopropyl ether. The likelihood of inactivation of the enzyme was found to be greatest toward the beginning of the reaction. In the latter phase of the reaction, inactivation probability was less and tended to remain constant until the completion of the reaction. PMID:10486131

Warrington, J C; Saville, B A

1999-11-01

374

Ion Exchange and Solvent Extraction: Supramolecular Aspects of Solvent Exchange Volume 21  

SciTech Connect

Preface The theme of supramolecular chemistry (SC), entailing the organization of multiple species through noncovalent interactions, has permeated virtually all aspects of chemical endeavor over the past several decades. Given that the observed behavior of discrete molecular species depends upon their weak interactions with one another and with matrix components, one would have to conclude that SC must indeed form part of the fabric of chemistry itself. A vast literature now serves to categorize SC phenomena within a body of consistent terminology. The word supramolecular itself appears in the titles of dozens of books, several journals, and a dedicated encyclopedia. Not surprisingly, the theme of SC also permeates the field of solvent extraction (SX), inspiring the framework for this volume of Ion Exchange and Solvent Extraction. It is attempted in the six chapters of this volume to identify both how supramolecular behavior occurs and is studied in the context of SX and how SC is influencing the current direction of SX. Researchers and practitioners have long dealt with supramolecular interactions in SX. Indeed, the use of polar extractant molecules in nonpolar media virtually assures that aggregative interactions will dominate the solution behavior of SX. Analytical chemists working in the 1930s to the 1950s with simple mono- and bidentate chelating ligands as extractants noted that extraction of metal ions obeyed complicated mass-action equilibria involving complex stoichiometries. As chemists and engineers developed processes for nuclear and hydrometallurgical applications in the 1950s and 1960s, the preference for aliphatic diluents only enhanced the complexity and supramolecular nature of extraction chemistry. Use of physical techniques such as light scattering and vapor-pressure measurements together with various spectroscopic methods revealed organic-phase aggregates from well-defined dimers to small aggregates containing a few extractant molecules to large inverse micelles swollen with water molecules. Extraction systems involving long-chain cations such as alkylammonium species or long-chain anions such as sulfonates or carboxylates proved especially prone to extensive aggregate formation. The related phenomenon of third-phase formation in SX systems, long misunderstood, is now yielding to spectroscopic and scattering techniques showing extensive long-range organization. Over the last 50 years, tools for studying the structure and thermodynamics of aggregation have grown increasingly sophisticated, leading to a rich and detailed understanding of what we can now recognize as SC phenomena in SX. In the 1970s and 1980s, the rapid growth of SC elicited a paradigm shift in SX. The influence of SC principles had two major effects on the course of SX research. First, it provided a framework for understanding the supramolecular behavior that was already well appreciated in the field of SX, though earlier without the SC terminology. Second, it provided the conceptual tools to control supramolecular behavior in SX, direct it for intended functionality, and to simplify it. Extraction by designed reagents has been steadily progressing ever since, with commercial applications emerging to successfully validate this approach. With the discovery of crown ethers in the late 1960s, the advancement of extractant design has fruitfully employed the concept of inclusion. While considerable initial progress occurred with such molecules, especially because of their affinity and selectivity for alkali and alkaline earth metals, other molecular platforms such as calixarenes have proven more versatile. Multidentate receptors for partial to full inclusion of cations, anions, ion pairs, as well as neutral species, have now become commonplace for selective extraction. This volume of Ion Exchange and Solvent Extraction examines how the principles of SC are being employed both in advancing the design of new highly selective SX systems and in understanding aggregation phenomena in SX systems. Chapter 1 discusses the nature and definition of SC

Gloe, Karsten [Technischen Universität Dresden] [Technischen Universität Dresden; Tasker, Peter A [ORNL] [ORNL; Oshima, Tatsuya [University of Miyazaki] [University of Miyazaki; Watarai, Hitoshi [Institute for NanoScience Design at Osaka University] [Institute for NanoScience Design at Osaka University; Nilsson, Mikael [University of California, Irvine] [University of California, Irvine

2013-01-01

375

High pressure solvent extraction of maritime pine bark: Study of fractionation, solvent flow rate and solvent composition  

Microsoft Academic Search

Maritime pine bark, an abundant Portuguese residue rich in high-value phenolic compounds, was subjected to fractionated and non-fractionated high pressure extractions (F-HPE and NF-HPE, respectively). Supercritical carbon dioxide (scCO2) was the chosen solvent to extract the pine bark low-polarity fraction and ethanol (EtOH) was added to scCO2 to recover the phenolic fraction. The effect of the solvent flow rate was

I. J. Seabra; A. M. A. Dias; M. E. M. Braga; H. C. de Sousa

376

Motor coordination uses external spatial coordinates independent of developmental vision.  

PubMed

The constraints that guide bimanual movement coordination are informative about the processing principles underlying movement planning in humans. For example, symmetry relative to the body midline benefits finger and hand movements independent of hand posture. This symmetry constraint has been interpreted to indicate that movement coordination is guided by a perceptual code. Although it has been assumed implicitly that the perceptual system at the heart of this constraint is vision, this relationship has not been tested. Here, congenitally blind and sighted participants made symmetrical and non-symmetrical (that is, parallel) bimanual tapping and finger oscillation movements. For both groups, symmetrical movements were executed more correctly than parallel movements, independent of anatomical constraints like finger homology and hand posture. For the blind, the reliance on external spatial factors in movement coordination stands in stark contrast to their use of an anatomical reference frame in perceptual processing. Thus, the externally coded symmetry constraint evident in bimanual coordination can develop in the absence of the visual system, suggesting that the visual system is not critical for the establishment of an external-spatial reference frame in movement coordination. PMID:24727423

Heed, Tobias; Röder, Brigitte

2014-07-01

377

Interaction of organic solvents with protein structures at protein-solvent interface.  

PubMed

The effect of non-denaturing concentrations of three different organic solvents, formamide, acetone and isopropanol, on the structure of haloalkane dehalogenases DhaA, LinB, and DbjA at the protein-solvent interface was studied using molecular dynamics simulations. Analysis of B-factors revealed that the presence of a given organic solvent mainly affects the dynamical behavior of the specificity-determining cap domain, with the exception of DbjA in acetone. Orientation of organic solvent molecules on the protein surface during the simulations was clearly dependent on their interaction with hydrophobic or hydrophilic surface patches, and the simulations suggest that the behavior of studied organic solvents in the vicinity of hyrophobic patches on the surface is similar to the air/water interface. DbjA was the only dimeric enzyme among studied haloalkane dehalogenases and provided an opportunity to explore effects of organic solvents on the quaternary structure. Penetration and trapping of organic solvents in the network of interactions between both monomers depends on the physico-chemical properties of the organic solvents. Consequently, both monomers of this enzyme oscillate differently in different organic solvents. With the exception of LinB in acetone, the structures of studied enzymes were stabilized in water-miscible organic solvents. PMID:22760789

Khabiri, Morteza; Minofar, Babak; Brezovský, Jan; Damborský, Ji?í; Ettrich, Rudiger

2013-11-01

378

Implicit treatment of solvent dispersion forces in protein simulations.  

PubMed

A model is proposed for the evaluation of dispersive forces in a continuum solvent representation for use in large-scale computer simulations. The model captures the short- and long-range effects of water-exclusion in conditions of partial and anisotropic hydration. The model introduces three parameters, one of which represents the degree of hydration (water occupancy) at any point in the system, which depends on the solute conformation, and two that represent the strength of water-water and water-solute dispersive interactions. The model is optimized for proteins, using hydration data of a suboptimally hydrated binding site and results from dynamics simulations in explicit water. The model is applied to a series of aliphatic-alcohol/protein complexes and a set of binary and ternary complexes of various sizes. Implications for weak and ultra-weak protein-protein association and for simulation in crowded media are discussed. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. PMID:24919463

Hassan, Sergio A

2014-08-15

379

Nonlinear response of a linear chain to weak driving  

NASA Astrophysics Data System (ADS)

We study the escape of a chain of coupled units over the barrier of a metastable potential. It is demonstrated that a very weak external driving field with a suitably chosen frequency suffices to accomplish speedy escape. The latter requires passage through a transition state, the formation of which is triggered by permanent feeding of energy from a phonon background into humps of localized energy and elastic interaction of the arising breather solutions. In fact, cooperativity between the units of the chain entailing coordinated energy transfer is shown to be crucial for enhancing the rate of escape in an extremely effective and low-energy cost way where the effects of entropic localization and breather coalescence conspire.

Hennig, D.; Mulhern, C.; Burbanks, A. D.; Schimansky-Geier, L.

2014-01-01

380

Solvent effects on infrared spectra of methyl 4-hydroxybenzoate in pure organic solvents and in ethanol\\/CCl 4 binary solvents  

Microsoft Academic Search

Infrared spectroscopy studies of methyl 4-hydroxybenzoate (MHB) in 17 different organic solvents and in ethanol\\/CCl4 binary solvent were undertaken to investigate the solvent–solute interactions. The frequencies of carbonyl stretching vibration ?(C?O) of MHB in single solvents were correlated with the solvent acceptor number (AN) and the linear solvation energy relationships (LSER). The assignments of the two bands of ?(C?O) of

Qing Liu; Danjun Fang; Jianping Zheng

2004-01-01

381

Reorganization of Defense Coordinating Officer and Element.  

National Technical Information Service (NTIS)

The organization of Defense Coordinating Officers (DCOs) and Defense Coordinating Elements (DCEs) in 2005 impeded coordination and interagency cooperation during the federal response to Hurricane Katrina. In 2006, the program was reorganized to improve th...

T. L. Schilling

2012-01-01

382

Mechanisms of coordination in distributed neural circuits: encoding coordinating information.  

PubMed

We describe synaptic connections through which information essential for encoding efference copies reaches two coordinating neurons in each of the microcircuits that controls limbs on abdominal segments of the crayfish, Pacifastacus leniusculus. In each microcircuit, these coordinating neurons fire bursts of spikes simultaneously with motor neurons. These bursts encode timing, duration, and strength of each motor burst. Using paired microelectrode recordings, we demonstrate that one class of nonspiking neurons in each microcircuit's pattern-generating kernel-IPS-directly inhibits the ASCE coordinating neuron that copies each burst in power-stroke (PS) motor neurons. This inhibitory synapse parallels IPS's inhibition of the same PS motor neurons. Using a disynaptic pathway to control its membrane potential, we demonstrate that a second type of nonspiking interneuron in the pattern-generating kernel-IRSh-inhibits the DSC coordinating neuron that copies each burst in return-stroke (RS) motor neurons. This inhibitory synapse parallels IRS's inhibition of the microcircuit's RS motor neurons. Experimental changes in the membrane potential of one IPS or one IRSh neuron simultaneously changed the strengths of motor bursts, durations, numbers of spikes, and spike frequency in the simultaneous ASCE and DSC bursts. ASCE and DSC coordinating neurons link the segmentally distributed microcircuits into a coordinated system that oscillates with the same period and with stable phase differences. The inhibitory synapses from different pattern-generating neurons that parallel their inhibition of different sets of motor neurons enable ASCE and DSC to encode details of each oscillation that are necessary for stable, adaptive synchronization of the system. PMID:24741053

Smarandache-Wellmann, Carmen; Grätsch, Swantje

2014-04-16

383

Deasphalted oil: A natural asphaltene solvent  

SciTech Connect

Asphaltene deposition in the near-wellbore region can block pore throats, change wettability characteristics and relative-permeability relationships, and therefore, reduce oil production. Conventional aromatic solvents (e.g., toluene and xylene) alone or in combination with various dispersants are used to remove asphaltene damage from the near-wellbore region. However, these aromatic solvents are expensive and are not environmentally friendly. The objective of this work was to systematically evaluate the asphaltene-solvating power of various nonconventional solvents, including deasphalted oil, using a light-scattering technique. Experimental results suggest that deasphalted oil is a strong asphaltene solvent presumably because of its native resin and aromatic contents. Addition of asphaltene dispersants also increases the solubilizing power of the deasphalted oil. Furthermore, various refinery and heavy oil upgrader streams show strong ability to solubilize asphaltenes.

Jamaluddin, A.K.M. [Noranda Technology Centre, Pointe Claire, Quebec (Canada); Nazarko, T.W.; Sills, S. [Norcen Energy Resources Ltd., Calgary, Alberta (Canada); Fuhr, B.J. [Alberta Research Council, Edmonton, Alberta (Canada)

1996-08-01

384

Solvent mediated self-assembly of solids.  

National Technical Information Service (NTIS)

The purpose of this proposal is to understand the interplay between solution chemistry, molecular structure, surface chemistry, and the processes of nucleation and crystal growth in solvent-mediated systems, with the goal of developing the atomic and mole...

J. De Yoreo, W. D. Wilson, T. Palmore

1997-01-01

385

Volatile Solvent Use among Western Australian Adolescents.  

ERIC Educational Resources Information Center

Semistructured interviews were conducted with 40 adolescents who reported inhaling volatile solvents. All were aware of the short-term health risks involved in use, and most reported experiencing ill effects. Offers suggestions for intervention. (Author/GCP)

Carroll, Annemaree; Houghton, Stephen; Odgers, Peta

1998-01-01

386

Solvent Dispersion and Flow Meter Calculation Results.  

National Technical Information Service (NTIS)

Savannah River National Laboratory (SRNL) found that the dispersion numbers for the six combinations of CSSX: Next Generation Solvent (NGS) blend and pure NGS versus salt solution, caustic wash, and strip aqueous solutions are all good. The dispersion num...

C. A. Nash F. F. Fondeur T. B. Peters

2013-01-01

387

Theory of solvent influence on reaction dynamics  

NASA Astrophysics Data System (ADS)

A generalization of the recently published quantum-classical approximation [A. A. Neufeld, J. Chem. Phys., 119, 2488 (2003)] for the purposes of reaction dynamics in condensed phase is presented. The obtained kinetic equations treat a solvent influence in a nonphenomenological way, account for the change of the free energy of the surrounding media, allow for different solvent dynamics in each reaction channel, and constitute a powerful framework for an accurate modeling of solvent effects, including ultrafast processes. The key features of the approach are its differential form, which considerably facilitates practical applications, and well defined wide applicability limits. The developed methodology fully accounts for an arbitrary long memory of the canonical bath and covers solvent-induced processes from a subpicosecond time scale.

Neufeld, A. A.

2005-04-01

388

"Solvent Effects" in 1H NMR Spectroscopy.  

ERIC Educational Resources Information Center

Describes a simple undergraduate experiment in chemistry dealing with the "solvent effects" in nuclear magnetic resonance (NMR) spectroscopy. Stresses the importance of having students learn NMR spectroscopy as a tool in analytical chemistry. (TW)

Cavaleiro, Jose A. S.

1987-01-01

389

Promoting Coordination for Disaster Relief - From Crowdsourcing to Coordination  

NASA Astrophysics Data System (ADS)

The efficiency at which governments and non-governmental organizations (NGOs) are able to respond to a crisis and provide relief to victims has gained increased attention. This emphasis coincides with significant events such as tsunamis, hurricanes, earthquakes, and environmental disasters occuring during the last decade. Crowdsourcing applications such as Twitter, Ushahidi, and Sahana have proven useful for gathering information about a crisis yet have limited utility for response coordination. In this paper, we briefly describe the shortfalls of current crowdsourcing applications applied to disaster relief coordination and discuss one approach aimed at facilitating efficient collaborations amongst disparate organizations responding to a crisis.

Gao, Huiji; Wang, Xufei; Barbier, Geoffrey; Liu, Huan

390

Coordination effects on the electronic structure of the CuA site of cytochrome c oxidase  

NASA Astrophysics Data System (ADS)

The CuA site is the electron mediator in cytochrome c oxidase (CcO), providing an appropriate electronic structure for rapid electron transfer. We have studied the coordinating effects of His, Met, and the peptide carbonyl group of Glu of the CuA site, using the density functional theory. Our computation demonstrates that the His ligation provides strong orbital and electrostatic effects on the electronic structure of the CuA site, while that the Met coordination gives weak orbital and electrostatic effects. A coordination of the peptide carbonyl group affects the electronic structure of the CuA site only electrostatically.

Koizumi, Kenichi; Shigeta, Yasuteru; Okuyama, Orio; Nakamura, Haruki; Takano, Yu

2012-04-01

391

Process for solvent refining of coal using a denitrogenated and dephenolated solvent  

DOEpatents

A process is disclosed for the solvent refining of non-anthracitic coal at elevated temperatures and pressure in a hydrogen atmosphere using a hydrocarbon solvent which before being recycled in the solvent refining process is subjected to chemical treatment to extract substantially all nitrogenous and phenolic constituents from the solvent so as to improve the conversion of coal and the production of oil in the solvent refining process. The solvent refining process can be either thermal or catalytic. The extraction of nitrogenous compounds can be performed by acid contact such as hydrogen chloride or fluoride treatment, while phenolic extraction can be performed by caustic contact or contact with a mixture of silica and alumina.

Garg, Diwakar (Macungie, PA); Givens, Edwin N. (Bethlehem, PA); Schweighardt, Frank K. (Allentown, PA)

1984-01-01

392

Method of stripping metals from organic solvents  

DOEpatents

A new method to strip metals from organic solvents in a manner that allows for the recycle of the stripping agent. The method utilizes carbonate solutions of organic amines with complexants, in low concentrations, to strip metals from organic solvents. The method allows for the distillation and reuse of organic amines. The concentrated metal/complexant fraction from distillation is more amenable to immobilization than solutions resulting from current practice.

Todd, Terry A. (Aberdeen, ID); Law, Jack D. (Pocatello, ID); Herbst, R. Scott (Idaho Falls, ID); Romanovskiy, Valeriy N. (St. Petersburg, RU); Smirnov, Igor V. (St.-Petersburg, RU); Babain, Vasily A. (St-Petersburg, RU); Esimantovski, Vyatcheslav M. (St-Petersburg, RU)

2009-02-24

393

Solubility of hydrogen sulfide in organic solvents  

Microsoft Academic Search

The solubilities of hydrogen sulfide expressed in mole fractions may be related, through multiparameter equations, to parameters\\u000a that account for the specific and nonspecific solvation ability of the solvent and for the cohesion energy. The key factors\\u000a are the self-association of the solvent, which reduces the solubility, and the complexing ability with hydrogen sulfide, which\\u000a increases the solubility.

S. D. Bryk; R. G. Makitra; E. Ya. Pal’chikova

2006-01-01

394

Generalized spherical and simplicial coordinates  

NASA Astrophysics Data System (ADS)

Elementary trigonometric quantities are defined in l2,p analogously to that in l2,2, the sine and cosine functions are generalized for each p>0 as functions sinp and cosp such that they satisfy the basic equation cosp([phi])p+sinp([phi])p=1. The p-generalized radius coordinate of a point [xi][set membership, variant]Rn is defined for each p>0 as . On combining these quantities, ln,p-spherical coordinates are defined. It is shown that these coordinates are nearly related to ln,p-simplicial coordinates. The Jacobians of these generalized coordinate transformations are derived. Applications and interpretations from analysis deal especially with the definition of a generalized surface content on ln,p-spheres which is nearly related to a modified co-area formula and an extension of Cavalieri's and Torricelli's indivisibeln method, and with differential equations. Applications from probability theory deal especially with a geometric interpretation of the uniform probability distribution on the ln,p-sphere and with the derivation of certain generalized statistical distributions.

Richter, Wolf-Dieter

2007-12-01

395

Weak gauge boson radiation in parton showers  

NASA Astrophysics Data System (ADS)

The emission of W and Z gauge bosons off quarks is included in a traditional QCD + QED shower. The unitarity of the shower algorithm links the real radiation of the weak gauge bosons to the negative weak virtual corrections. The shower evolution process leads to a competition between QCD, QED and weak radiation, and allows for W and Z boson production inside jets. Various effects on LHC physics are studied, both at low and high transverse momenta, and effects at higher-energy hadron colliders are outlined.

Christiansen, Jesper R.; Sjöstrand, Torbjörn

2014-04-01

396

Polaronic effects and thermally enhanced weak superconductivity  

NASA Astrophysics Data System (ADS)

We theoretically analyze the d.c. Josephson current between two superconductors connected by a vibrating weak link. Assuming the weak link to be a "quantum dot", we predict that the critical current is thermally enhanced at low temperatures if the electron-vibron interaction is strong and has an anomalous temperature dependence in a large temperature interval. We estimate that this unusual behavior, which occurs because the current through the weak link is carried by "polaronic" Andreev states, is measurable in experiments on, e.g., carbon-nanotube-based Josephson junctions.

Parafilo, A. V.; Krive, I. V.; Shekhter, R. I.; Park, Y. W.; Jonson, M.

2014-03-01

397

Biodesulfurization in biphasic systems containing organic solvents.  

PubMed

Biphasic systems can overcome the problem of low productivity in conventional media and have been exploited for biocatalysis. Solvent-tolerant microorganisms are useful in biotransformation with whole cells in biphasic reactions. A solvent-tolerant desulfurizing bacterium, Pseudomonas putida A4, was constructed by introducing the biodesulfurizing gene cluster dszABCD, which was from Rhodococcus erythropolis XP, into the solvent-tolerant strain P. putida Idaho. Biphasic reactions were performed to investigate the desulfurization of various sulfur-containing heterocyclic compounds in the presence of various organic solvents. P. putida A4 had the same substrate range as R. erythropolis XP and could degrade dibenzothiophene at a specific rate of 1.29 mM g (dry weight) of cells(-1) h(-1) for the first 2 h in the presence of 10% (vol/vol) p-xylene. P. putida A4 was also able to degrade dibenzothiophene in the presence of many other organic solvents at a concentration of 10% (vol/vol). This study is a significant step in the exploration of the biotechnological potential of novel biocatalysts for developing an efficient biodesulfurization process in biphasic reaction mixtures containing toxic organic solvents. PMID:16820450

Tao, Fei; Yu, Bo; Xu, Ping; Ma, Cui Qing

2006-07-01

398

Biodesulfurization in Biphasic Systems Containing Organic Solvents†  

PubMed Central

Biphasic systems can overcome the problem of low productivity in conventional media and have been exploited for biocatalysis. Solvent-tolerant microorganisms are useful in biotransformation with whole cells in biphasic reactions. A solvent-tolerant desulfurizing bacterium, Pseudomonas putida A4, was constructed by introducing the biodesulfurizing gene cluster dszABCD, which was from Rhodococcus erythropolis XP, into the solvent-tolerant strain P. putida Idaho. Biphasic reactions were performed to investigate the desulfurization of various sulfur-containing heterocyclic compounds in the presence of various organic solvents. P. putida A4 had the same substrate range as R. erythropolis XP and could degrade dibenzothiophene at a specific rate of 1.29 mM g (dry weight) of cells?1 h?1 for the first 2 h in the presence of 10% (vol/vol) p-xylene. P. putida A4 was also able to degrade dibenzothiophene in the presence of many other organic solvents at a concentration of 10% (vol/vol). This study is a significant step in the exploration of the biotechnological potential of novel biocatalysts for developing an efficient biodesulfurization process in biphasic reaction mixtures containing toxic organic solvents.

Tao, Fei; Yu, Bo; Xu, Ping; Ma, Cui Qing

2006-01-01

399

Solvent Extraction and Ion Exchange in Radiochemistry  

NASA Astrophysics Data System (ADS)

In 1805, Bucholz extracted uranium from a nitric acid solution into ether and back-extracted it into pure water. This is probably the first reported solvent-extraction investigation. During the following decades, the distribution of neutral compounds between aqueous phases and pure solvents was studied, e.g., by Peligot, Berthelot and Jungfleisch, and Nernst. Selective extractants for analytical purposes became available during the first decades of the twentieth century. From about 1940, extractants such as organophosphorous esters and amines were developed for use in the nuclear fuel cycle. This connection between radiochemistry and solvent-extraction chemistry made radiochemists heavily involved in the development of new solvent extraction processes, and eventually solvent extraction became a major separation technique in radiochemistry. About 160 years ago, Thompson and Way observed that soil can remove potassium and ammonium ions from an aqueous solution and release calcium ions. This is probably the first scientific report on an ion-exchange separation. The first synthesis of the type of organic ion exchangers that are used today was performed by Adams and Holmes in 1935. Since then, ion-exchange techniques have been used extensively for separations of various radionuclides in trace as well as macro amounts. During the last 4 decades, inorganic ion exchangers have also found a variety of applications. Today, solvent extraction as well as ion exchange are used extensively in the nuclear industry and for nuclear, chemical, and medical research. Some of these applications are discussed in the chapter.

Skarnemark, G.

400

Dynamics around solutes and solute-solvent complexes in mixed solvents  

Microsoft Academic Search

Ultrafast 2D-IR vibrational echo experiments, IR pump-probe ex- periments, and FT-IR spectroscopy of the hydroxyl stretch of phenol-OD in three solvents, CCl4, mesitylene (1, 3, 5 trimethyl- benzene), and the mixed solvent of mesitylene and CCl4 (0.83 mole fraction CCl4), are used to study solute-solvent dynamics via ob- servation of spectral diffusion. Phenol forms a complex with Mesitylene. In the

Kyungwon Kwak; M. D. Fayer

2007-01-01

401

Caustic-Side Solvent Extraction: Chemical and Physical Properties of the Optimized Solvent  

SciTech Connect

This work was undertaken to optimize the solvent used in the Caustic Side Solvent Extraction (CSSX) process and to measure key chemical and physical properties related to its performance in the removal of cesium from the alkaline high-level salt waste stored in tanks at the Savannah River Site. The need to adjust the solvent composition arose from the prior discovery that the previous baseline solvent was supersaturated with respect to the calixarene extractant. The following solvent-component concentrations in Isopar{reg_sign} L diluent are recommended: 0.007 M calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) extractant, 0.75 M 1-(2,2,3,3-tetrafluoropropoxy)-3-(4-sec-butylphenoxy)-2-propanol (Cs-7SB) phase modifier, and 0.003 M tri-n-octylamine (TOA) stripping aid. Criteria for this selection included BOBCalixC6 solubility, batch cesium distribution ratios (D{sub Cs}), calculated flowsheet robustness, third-phase formation, coalescence rate (dispersion numbers), and solvent density. Although minor compromises within acceptable limits were made in flowsheet robustness and solvent density, significant benefits were gained in lower risk of third-phase formation and lower solvent cost. Data are also reported for the optimized solvent regarding the temperature dependence of D{sub Cs} in extraction, scrubbing, and stripping (ESS); ESS performance on recycle; partitioning of BOBCalixC6, Cs-7SB, and TOA to aqueous process solutions; partitioning of organic anions; distribution of metals; solvent phase separation at low temperatures; solvent stability to elevated temperatures; and solvent density and viscosity. Overall, the technical risk of the CSSX process has been reduced by resolving previously identified issues and raising no new issues.

Delmau, L.H.

2002-10-08

402

Phase separation phenomena of polysulfone\\/solvent\\/organic nonsolvent and polyethersulfone\\/solvent\\/organic nonsolvent systems  

Microsoft Academic Search

The precipitation values (PVs) of several organic nonsolvents in polysulfone (PSf)\\/solvent and polyethersulfone (PESf)\\/solvent systems were measured in temperatures ranging from 10 to 80 C by the direct titration method and compared with those of water in the same systems. The solvents used were N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAC); the organic nonsolvents employed were methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, ethylene

Dongliang Wang; K. Li; S. Sourirajan; W. K. Teo

1993-01-01

403

Comparison of solvent mixtures for pressurized solvent extraction of soil fatty acid biomarkers  

Microsoft Academic Search

The extraction and transesterification of soil lipids into fatty acid methyl esters (FAMEs) is a useful technique for studying soil microbial communities. The objective of this study was to find the best solvent mixture to extract soil lipids with a pressurized solvent extractor system. Four solvent mixtures were selected for testing: chloroform:methanol:phosphate buffer (1:2:0.8, v\\/v\\/v), chloroform:methanol (1:2, v\\/v), hexane:2-propanol (3:2,

Richard Jeannotte; Chantal Hamel; Suha Jabaji; Joann K. Whalen

2008-01-01

404

Effective pair gap of weakly bound neutrons in deformed nuclei  

SciTech Connect

The dependence of effective pair gap on weakly bound neutron orbits is studied in deformed nuclei in comparison with that in spherical nuclei, solving the Hartree-Fock-Bogoliubov equation in a simplified model in coordinate space with the correct asymptotic boundary conditions. In spherical nuclei the effective pair gap of s{sub 1/2} neutrons decreases to zero in the limit that the corresponding Hartree-Fock one-particle energy approaches zero. In the same limit, the effective pair gap of {omega}{sup {pi}}=1/2{sup +} neutrons in deformed nuclei becomes very small when the wave functions of {omega}{sup {pi}}=1/2{sup +} orbits contain an appreciable amount of s{sub 1/2} components, even if a considerable amount of larger-l components remains in the wave functions. Then, the one-particle excitation spectra of deformed even-even neutron-drip-line nuclei, in which an {omega}{sup {pi}}=1/2{sup +} level is weakly bound, can start at much lower energy than twice the average pair gap in the presence of many-body pair correlation.

Hamamoto, Ikuko [Division of Mathematical Physics, Lund Institute of Technology at the University of Lund, Lund (Sweden); Niels Bohr Institute, Blegdamsvej 17, Copenhagen O, DK-2100 (Denmark)

2005-03-01

405

CHEMICAL STABILITY OF POLYPHENYLENE SULFIDE IN THE NEXT GENERATION SOLVENT FOR CAUSTIC-SIDE SOLVENT EXTRACTION  

SciTech Connect

The Office of Waste Processing, within the Office of Technology Innovation and Development, is funding the development of an enhanced solvent for deployment at the Savannah River Site for removal of cesium from High Level Waste. For simplicity, this solvent is referred to as the Next Generation Solvent (NGS). The technical effort is collaboration between Oak Ridge National Laboratory (ORNL), Savannah River National Laboratory (SRNL), and Argonne National Laboratory. The initial deployment target envisioned for the technology was within the Modular Caustic-Side Solvent Extraction Unit (MCU). Deployment of a new chemical within an existing facility requires verification that the chemical components are compatible with the installed equipment. In the instance of a new organic solvent, the primary focus is on compatibility of the solvent with polyphenylene sulfide (PPS), the polymer used in the coalescers within MCU. This report provides the data from exposing PPS polymer to NGS. The test was conducted over a three month period. PPS is remarkably stable in the presence of the next generation solvent. Testing showed no indication of swelling or significant leaching. Preferential sorption of the Modifier on PPS was observed but the same behavior occurs with the baseline solvent. Therefore, PPS coalescers exposed to the NGS are expected to perform comparably to those in contact with the baseline solvent.

Fondeur, F.; Fink, S.

2011-12-08

406

Computational studies of the unusual water adduct [Cp2TiMe(OH2)](+): the roles of the solvent and the counterion.  

PubMed

The recently reported cationic titanocene complex [Cp2TiMe(OH2)](+) was subjected to detailed computational studies using density functional theory (DFT). The calculated NMR spectra revealed the importance of including the anion and the solvent (CD2Cl2) in order to calculate spectra which were in good agreement with the experimental data. Specifically, two organic solvent molecules were required to coordinate to the two hydrogens of the bound OH2 in order to achieve such agreement. Further elaboration of the role of the solvent led to Bader's QTAIM and natural bond order calculations. The zirconocene complex [Cp2ZrMe(OH2)](+) was simulated for comparison. PMID:24756240

Saßmannshausen, Jörg

2014-08-01

407

Features in Continuous Parallel Coordinates.  

PubMed

Continuous Parallel Coordinates (CPC) are a contemporary visualization technique in order to combine several scalar fields, given over a common domain. They facilitate a continuous view for parallel coordinates by considering a smooth scalar field instead of a finite number of straight lines. We show that there are feature curves in CPC which appear to be the dominant structures of a CPC. We present methods to extract and classify them and demonstrate their usefulness to enhance the visualization of CPCs. In particular, we show that these feature curves are related to discontinuities in Continuous Scatterplots (CSP). We show this by exploiting a curve-curve duality between parallel and Cartesian coordinates, which is a generalization of the well-known point-line duality. Furthermore, we illustrate the theoretical considerations. Concluding, we discuss relations and aspects of the CPC's/CSP's features concerning the data analysis. PMID:22034308

Lehmann, Dirk J; Theisel, Holger

2011-12-01

408

Measuring Motor Coordination in Mice  

PubMed Central

Mice are increasingly being used in behavioral neuroscience, largely replacing rats as the behaviorist's animal of choice. Before aspects of behavior such as emotionality or cognition can be assessed, however, it is vital to determine whether the motor capabilities of e.g. a mutant or lesioned mouse allow such an assessment. Performance on a maze task requiring strength and coordination, such as the Morris water maze, might well be impaired in a mouse by motor, rather than cognitive, impairments, so it is essential to selectively dissect the latter from the former. For example, sensorimotor impairments caused by NMDA antagonists have been shown to impair water maze performance2. Motor coordination has traditionally been assessed in mice and rats by the rotarod test, in which the animal is placed on a horizontal rod that rotates about its long axis; the animal must walk forwards to remain upright and not fall off. Both set speed and accelerating versions of the rotarod are available. The other three tests described in this article (horizontal bar, static rods and parallel bars) all measure coordination on static apparatus. The horizontal bar also requires strength for adequate performance, particularly of the forelimbs as the mouse initially grips the bar just with the front paws. Adult rats do not perform well on tests such as the static rods and parallel bars (personal observations); they appear less well coordinated than mice. I have only tested male rats, however, and male mice seem generally less well coordinated than females. Mice appear to have a higher strength:weight ratio than rats; the Latin name, Mus musculus, seems entirely appropriate. The rotarod, the variations of the foot fault test12 or the Catwalk (Noldus)15 apparatus are generally used to assess motor coordination in rats.

Deacon, Robert M.J.

2013-01-01

409

Measuring motor coordination in mice.  

PubMed

Mice are increasingly being used in behavioral neuroscience, largely replacing rats as the behaviorist's animal of choice. Before aspects of behavior such as emotionality or cognition can be assessed, however, it is vital to determine whether the motor capabilities of e.g. a mutant or lesioned mouse allow such an assessment. Performance on a maze task requiring strength and coordination, such as the Morris water maze, might well be impaired in a mouse by motor, rather than cognitive, impairments, so it is essential to selectively dissect the latter from the former. For example, sensorimotor impairments caused by NMDA antagonists have been shown to impair water maze performance(2). Motor coordination has traditionally been assessed in mice and rats by the rotarod test, in which the animal is placed on a horizontal rod that rotates about its long axis; the animal must walk forwards to remain upright and not fall off. Both set speed and accelerating versions of the rotarod are available. The other three tests described in this article (horizontal bar, static rods and parallel bars) all measure coordination on static apparatus. The horizontal bar also requires strength for adequate performance, particularly of the forelimbs as the mouse initially grips the bar just with the front paws. Adult rats do not perform well on tests such as the static rods and parallel bars (personal observations); they appear less well coordinated than mice. I have only tested male rats, however, and male mice seem generally less well coordinated than females. Mice appear to have a higher strength:weight ratio than rats; the Latin name, Mus musculus, seems entirely appropriate. The rotarod, the variations of the foot fault test(12) or the Catwalk (Noldus)(15) apparatus are generally used to assess motor coordination in rats. PMID:23748408

Deacon, Robert M J

2013-01-01

410

Coordination artifacts: environment-based coordination for intelligent agents  

Microsoft Academic Search

Direct interaction and explicit communication are not always the best approaches for achieving coherent systemic behaviour in the context of Multi-Agent Systems (MAS). This is evident when taking into account recent approaches dealing with environment-based coordination such as stigmergy and, more generally, mediated interaction. In this paper we propose a conceptual, formal and engineering framework based on the notion of

Andrea Omicini; Alessandro Ricci; M. Viroli; Cristiano Castelfranchi; Luca Tummolini

2004-01-01

411

Coordination Artifacts: Environment-Based Coordination for Intelligent Agents  

Microsoft Academic Search

Direct interaction and explicit communication are not always the best approaches for achieving coherent systemic behaviour in the context of Multi-Agent Systems (MAS). This is evident when taking into account recent approaches dealing with environment-based coordination such as stigmergy and, more generally, mediated interaction. In this paper we propose a conceptual, formal and engineering framework based on the notion of

Andrea Omicini; Alessandro Ricci; Mirko Viroli; Cristiano Castelfranchi; Luca Tummolini

2004-01-01

412

Definition and determination of the triplet-triplet energy transfer reaction coordinate  

NASA Astrophysics Data System (ADS)

A definition of the triplet-triplet energy transfer reaction coordinate within the very weak electronic coupling limit is proposed, and a novel theoretical formalism is developed for its quantitative determination in terms of internal coordinates The present formalism permits (i) the separation of donor and acceptor contributions to the reaction coordinate, (ii) the identification of the intrinsic role of donor and acceptor in the triplet energy transfer process, and (iii) the quantification of the effect of every internal coordinate on the transfer process. This formalism is general and can be applied to classical as well as to nonvertical triplet energy transfer processes. The utility of the novel formalism is demonstrated here by its application to the paradigm of nonvertical triplet-triplet energy transfer involving cis-stilbene as acceptor molecule. In this way the effect of each internal molecular coordinate in promoting the transfer rate, from triplet donors in the low and high-energy limit, could be analyzed in detail.

Zapata, Felipe; Marazzi, Marco; Castaño, Obis; Acuña, A. Ulises; Frutos, Luis Manuel

2014-01-01

413

Elucidation of the Structure of Organic Solutions in Solvent Extraction by Combining Molecular Dynamics and X-ray Scattering.  

PubMed

Knowledge of the supramolecular structure of the organic phase containing amphiphilic ligand molecules is mandatory for full comprehension of ionic separation during solvent extraction. Existing structural models are based on simple geometric aggregates, but no consensus exists on the interaction potentials. Herein, we show that molecular dynamics crossed with scattering techniques offers key insight into the complex fluid involving weak interactions without any long-range ordering. Two systems containing mono- or diamide extractants in heptane and contacted with an aqueous phase were selected as examples to demonstrate the advantages of coupling the two approaches for furthering fundamental studies on solvent extraction. PMID:24729509

Ferru, Geoffroy; Gomes Rodrigues, Donatien; Berthon, Laurence; Diat, Olivier; Bauduin, Pierre; Guilbaud, Philippe

2014-05-19

414

Using Galaxies to Understand Weak Lensing  

NASA Astrophysics Data System (ADS)

While weak lensing measurements can provide a useful probe of galaxy-scale physics, it is not commonly appreciated that an understanding of galaxy-scale physics can in turn be used to dramatically improve weak lensing measurements. I will explain how galaxy scaling relations can enhance the weak lensing signal, and show recent results from a lensing magnification measurement using data from the Sloan Digital Sky Survey. The combination of magnification and shear measurements enabled by these techniques will permit significantly better weak lensing constraints on the distribution of mass on galaxy scales, in time for the newest generation of large, high-precision imaging surveys such as the Dark Energy Survey. I also discuss projections of what DES will be able to accomplish on this front.

Huff, Eric M.

2013-07-01

415

Sodium in weak G-band giants  

NASA Technical Reports Server (NTRS)

Sodium abundances have been determined for eight weak G-band giants whose atmospheres are greatly enriched with products of the CN-cycling H-burning reactions. Systematic errors are minimized by comparing the weak G-band giants to a sample of similar but normal giants. If, further, Ca is selected as a reference element, model atmosphere-related errors should largely be removed. For the weak-G-band stars (Na/Ca) = 0.16 +/- 0.01, which is just possibly greater than the result (Na/Ca) = 0.10 /- 0.03 from the normal giants. This result demonstrates that the atmospheres of the weak G-band giants are not seriously contaminated with products of ON cycling.

Drake, Jeremy J.; Lambert, David L.

1994-01-01

416

The Sloan Nearby Cluster Weak Lensing Survey  

SciTech Connect

We describe and present initial results of a weak lensing survey of nearby (z {approx}< 0.1) galaxy clusters in the Sloan Digital Sky Survey (SDSS). In this first study, galaxy clusters are selected from the SDSS spectroscopic galaxy cluster catalogs of Miller et al. and Berlind et al. We report a total of seven individual low-redshift cluster weak lensing measurements that include A2048, A1767, A2244, A1066, A2199, and two clusters specifically identified with the C4 algorithm. Our program of weak lensing of nearby galaxy clusters in the SDSS will eventually reach {approx}200 clusters, making it the largest weak lensing survey of individual galaxy clusters to date.

Kubo, Jeffrey M.; /Fermilab; Annis, James T.; /Fermilab; Hardin, Frances Mei; /Illinois Math. Sci. Acad.; Kubik, Donna; /Fermilab; Lawhorn, Kelsey; /Illinois Math. Sci. Acad.; Lin, Huan; /Fermilab; Nicklaus, Liana; /Illinois Math. Sci. Acad.; Nelson, Dylan; /UC, Berkeley; Reis, Ribamar Rondon de Rezende; /Fermilab; Seo, Hee-Jong; /Fermilab; Soares-Santos, Marcelle; /Fermilab /Inst. Geo. Astron., Havana /Sao Paulo U. /Fermilab

2009-08-01

417

Weak lensing analysis in three dimensions  

NASA Astrophysics Data System (ADS)

We present a comprehensive full-sky 3-dimensional analysis of the weak lensing fields and their corresponding power spectra. Using the formalism of spin-weight spherical harmonics and spherical Bessel functions, we relate the two-point statistics of the harmonic expansion coefficients of the weak lensing shear and convergence to the power spectrum of the matter density perturbations, and derive small-angle limits. Such a study is relevant in view of the next generation of large-scale weak lensing surveys which will provide distance information about the sources through photometric redshifts. This opens up the possibility of accurate cosmological parameter estimation via weak lensing, with an emphasis on the equation of state of dark energy.

Castro, P. G.; Heavens, A. F.; Kitching, T. D.

2005-07-01

418

Conductivity of Strong, Weak, and Nonelectrolyte Solutions  

NSDL National Science Digital Library

This is a video clip of strong, weak, and nonelectrolyte solutions conducting electricity. Each solution is tested with the light bulb apparatus and the bulb glows brightly, dimly, or not at all depending on the solution.

Ward, Charles

2007-12-20

419

Amplification of Angular Rotations Using Weak Measurements  

NASA Astrophysics Data System (ADS)

We present a weak measurement protocol that permits a sensitive estimation of angular rotations based on the concept of weak-value amplification. The shift in the state of a pointer, in both angular position and the conjugate orbital angular momentum bases, is used to estimate angular rotations. This is done by an amplification of both the real and imaginary parts of the weak-value of a polarization operator that has been coupled to the pointer, which is a spatial mode, via a spin-orbit coupling. Our experiment demonstrates the first realization of weak-value amplification in the azimuthal degree of freedom. We have achieved effective amplification factors as large as 100, providing a sensitivity that is on par with more complicated methods that employ quantum states of light or extremely large values of orbital angular momentum.

Magaña-Loaiza, Omar S.; Mirhosseini, Mohammad; Rodenburg, Brandon; Boyd, Robert W.

2014-05-01

420

Cation-Coordinating Properties of Perfluoro-15-Crown-5  

PubMed Central

The coordinative properties of perfluoro-15-crown-5 with monocations were investigated using 19F NMR spectroscopy and ion-selective electrodes with perfluoro-15-crown-5 as the matrix of their sensor membranes and the fluorophilic tetrakis[3,5-bis(perfluorohexyl)phenyl]borate as ion exchanger site. The results show that perfluoro-15-crown-5 interacts weakly but significantly with Na+ and K+. Assuming 1:1 stoichiometry, the formal complexation constants were determined to be 5.5 and 1.7 M?1, respectively. This weak binding is consistent with the strong electron withdrawing nature of the many fluorine atoms in the perfluorocrown ether. While perfluorinated crown ethers have been known to form host–guest complexes with the anions O2? and F? in the gas phase, this is the first study that quantitatively confirms cation binding to a perfluorocrown ether.

Lai, Chun-Ze; Reardon, Molly E.; Boswell, Paul G.; Buhlmann, Philippe

2011-01-01

421

Coordinates and the Cartesian Plane  

NSDL National Science Digital Library

The lesson begins with a short refresher lecture on how points are written in (x,y) format and orientation with the Cartesian plane axes. The lecture also covers which directions are positive and which are negative on an x-y plane. Students learn about what it means for a relation to be a function and how to determine domain and range of a set of data points. Prerequisite knowledge: Familiarity with the coordinate plane, coordinates, and equations are helpful, but not required.

VU Bioengineering RET Program, School of Engineering,; Mckelvey, Aubrey

2007-01-01

422

Measuring the galaxy-galaxy-mass three-point correlation function with weak gravitational lensing  

Microsoft Academic Search

We discuss the galaxy-galaxy-mass three-point correlation function and show how to measure it with weak gravitational lensing. The method entails choosing pairs of foreground lens galaxies, rotating them to the common coordinate system defined by the axis connecting them and then constructing a mean shear map by averaging the ellipticities of background source galaxies for a large number of foreground

David E. Johnston

2004-01-01

423

Locality, Weak or Strong Anticipation and Quantum Computing. I. Non-locality in Quantum Theory  

Microsoft Academic Search

The universal Turing machine is an anticipatory theory of computabil- ity by any digital or quantum machine. However the Church-Turing hypothesis only gives weak anticipation. The construction of the quantum computer (unlike classical computing) requires theory with strong anticipation. Category theory pro- vides the necessary coordinate-free mathematical language which is both construc- tive and non-local to subsume the various interpretations

M. A. Heather; B. N. Rossiter

424

Weak lensing analysis in three dimensions  

Microsoft Academic Search

We present a comprehensive full-sky 3-dimensional analysis of the weak lensing fields and their corresponding power spectra. Using the formalism of spin-weight spherical harmonics and spherical Bessel functions, we relate the two-point statistics of the harmonic expansion coefficients of the weak lensing shear and convergence to the power spectrum of the matter density perturbations, and derive small-angle limits. Such a

P. G. Castro; A. F. Heavens; T. D. Kitching

2005-01-01

425

Weak neutral currents in deep inelastic bremsstrahlung  

SciTech Connect

We consider the role of weak neutral currents in the processes Z/sup /plus minus// + N /yields/ Z/sup /plus minus// + /gamma/ + X. In the quark-parton model, with regard to hadronic radiation as well as leptonic, we obtain the differential cross-section of the processes, and investigate various P-odd effects that allow us to distinguish the weak current contribution.

Abdullaev, S.K.; Mukhtarov, A.I.; Mustafaev, V.Z.

1988-06-01

426

Diffraction effects in weakly nonlinear detonation waves  

Microsoft Academic Search

In the limit of small heat release, large activation energy and weak nonlinearity, the propagation of detonation waves obeys\\u000a a Geometrical Optics approximation. These equations develop caustic singularities, where the approximation fails. Here we\\u000a present a derivation of a modified set of equations for weakly nonlinear detonation waves incorporating lateral diffraction\\u000a effects. The modified set of equations does not fail

Rodolfo Rosales

427

Bulk Superconductivity in Weakly Localized Regime  

Microsoft Academic Search

The critical temperature, Tc, and the upper critical field, Hc2, have been examined for three-dimensional superconductors in the weakly localized regime. The life time, tau, is assumed to be short enough such that tau-1≫omegaD; omegaD being the Debye frequency. The results indicate that there exists an appreciable suppression of Tc even in the weakly localized regime. The effect of strong

Hidetoshi Fukuyama; Hiromichi Ebisawa; Sadamichi Maekawa

1984-01-01

428

Weakly chordal graph algorithms via handles  

Microsoft Academic Search

We use the notion of handle, introduced by Hayward, to improve algorithms for weakly chordal graphs. For recognition we reduce the time complexity from O(n2m) to O(rn 2) and the space complexity from O(n 3) to O(n + m), and also produce a hole or antihole if the input graph is not weakly chordal. For the optimization problems clique, independent

Ryan B. Hayward; Jeremy Spinrad; R. Sritharan

2000-01-01

429

Looking for heavier weak bosons with DUMAND  

NASA Technical Reports Server (NTRS)

One or more heavier weak bosons may coexist with the standard weak boson, a broad program may be laid out for a search for the heavier W's via change in the total cross section due to the additional propagator, a concomitant search, and a subsequent search for significant antimatter in the universe involving the same annihilation, but being independent of possible neutrino oscillations. The program is likely to require detectors sensitive to higher energies, such as acoustic detectors.

Brown, R. W.; Stecker, F. W.

1980-01-01

430

Deterministic implementation of weak quantum cubic nonlinearity  

SciTech Connect

We propose a deterministic implementation of weak cubic nonlinearity, which is a basic building block of a full-scale continuous-variable quantum computation. Our proposal relies on preparation of a specific ancillary state and transferring its nonlinear properties onto the desired target by means of deterministic Gaussian operations and feed forward. We show that, despite the imperfections arising from the deterministic nature of the operation, the weak quantum nonlinearity can be implemented and verified with the current level of technology.

Marek, Petr; Filip, Radim; Furusawa, Akira [Department of Optics, Palacky University, 17. listopadu 1192/12, CZ-771 46 Olomouc (Czech Republic); Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2011-11-15

431

Gyroviscous stress in weakly magnetized plasmas  

SciTech Connect

The gyroviscous stress is computed for a weakly magnetized plasma, i.e., one in which the thermal ion gyroradius may exceed the equilibrium gradient scale length. A simple and useful formula is derived and shown to reduce to the previous strongly magnetized result. Applicability is illustrated with a typical field-reversed configuration equilibrium solution. This form is the most useful to date for the study of kinetic ion phenomena in weakly magnetized plasmas within a fluid model.

Barnes, D. C. [Coronado Consulting, Lamy, New Mexico 87540 (United States)

2013-01-15

432

Molecular basis of weak D in Taiwanese  

Microsoft Academic Search

Two genes, RHD and RHCE, encode the antigens of the RH blood group system. The weak D phenotype is caused by many different RHD alleles encoding aberrant RhD proteins, resulting in distinct serologic phenotypes and anti-D immunization. We analyzed seven weak D phenotypes excluding D el, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct sequencing methods to detect

I.-L. Lin; M.-C. Shih; M.-H. Hsieh; T.-C. Liu; S.-E. Chang; C.-L. Lin; J.-G. Chang

2003-01-01

433

Lognormal Property of Weak Lensing Fields  

Microsoft Academic Search

The statistical properties of weak-lensing fields are studied quantitatively using ray-tracing simulations. Motivated by an empirical lognormal model that excellently characterizes the probability distribution function of a three-dimensional mass distribution, we critically investigate the validity of the lognormal model in weak-lensing statistics. Assuming that the convergence field kappa is approximately described by the lognormal distribution, we present analytic formulae of

Atsushi Taruya; Masahiro Takada; Takashi Hamana; Issha Kayo; Toshifumi Futamase

2002-01-01

434

Application of Möbius coordinate transformation in evaluating Newton's integral  

NASA Astrophysics Data System (ADS)

We propose a numerical scheme which efficiently combines various existing methods of solving the Newton's volume integral. It utilises the analytical solution of Newton's integral for tesseroid in computing the near-zone contribution to gravitational field quantities (potential and its first radial derivative). The far-zone gravitational contribution is computed using the expressions derived based on applying Molodensky's truncation coefficients to a spectral representation of Newton's integral. The weak singularity of Newton's integral is treated analytically using formulas for the gravitational contribution of the cylindrical mass volume centered with respect to the observation point. All three solutions are defined and evaluated in the system of polar spherical coordinates. A conversion of the geographical to polar spherical coordinates of input data sets (digital terrain and density models) is based on the Möbius transformation with an enhanced integration grid resolution at vicinity of the observation point.

Tenzer, Robert; Gladkikh, Vladislav

2011-01-01

435

A new layered Ca-succinate coordination polymer.  

PubMed

A new layered Ca-succinate coordination polymer, poly[?(3)-succinato-calcium(II)], [Ca(C(4)H(5)O(4))](n), was synthesized by reaction of CaCl(2)·2H(2)O and succinic acid in an aqueous medium under hydrothermal microwave conditions. The structure contains infinite layers of edge-sharing calcium pentagonal-bipyramidal polyhedra forming six-membered rings connected through succinate ligands. Such an assembly of inorganic building units is unique for calcium metal-organic framework-type structures. Adjacent layers are packed into a final pseudo-three-dimensional structure through weak C-H···O hydrogen bonds. PMID:22223278

Mazaj, Matjaz; Kaucic, Venceslav; Golobic, Amalija; Logar, Natasa Zabukovec

2012-01-01

436

Solvent dependence of 7-azaindole dimerization.  

PubMed

We have investigated 7-azaindole (AI) in a variety of solvents including CCl4, CHCl3, CH2Cl2, acetone, CH3CN, and DMSO by femtosecond Raman-induced Kerr effect spectroscopy. In differential low-frequency Kerr spectra between the solutions and the respective neat solvents, vibrational bands of the AI hydrogen-bonding (HB) dimer have been observed at ca. 90 and 105 cm(-1) in CHCl3 and CH2Cl2, as well as CCl4: the standard solvent for the AI dimer. In contrast, a broad monomodal band at ca. 80 cm(-1) characterizes an HB mode between the AI monomer and solvent in acetone, CH3CN, and DMSO. The overdamped Kerr transients in the picosecond region show evidence of both the AI monomer and dimer reorientations in CHCl3, CH2Cl2, acetone, and CH3CN, but only the monomer reorientation has been confirmed in DMSO. The clear intermolecular HB bands have not been observed in acetone, CH3CN, and DMSO because these solvents are sufficiently strong HB acceptors, which form HB AI-solvent complexes, thus preventing quantitative AI dimerization. In addition, it is plausible that the HB band of between AI and solvent obscures the intermolecular bands of the AI dimer when the concentration of the AI dimer is much lower than the AI monomer. For comparison, we have employed NMR to study the concentration-dependent chemical shift of the proton attached to the N at the 7-position of AI and to estimate the dimerization constant: 356, 13.3, 14.7, 0.727, and 0.910 M(-1) in CCl4, CHCl3, CH2Cl2, acetone, and CH3CN, respectively. The femtosecond Raman-induced Kerr effect spectroscopy and NMR results are in good agreement. PMID:24191715

Shirota, Hideaki; Fukuda, Takao; Kato, Tatsuya

2013-12-19

437

Coordination between cobalt (II) ion and carbonyl group in acetone probed by using DAOSD approach  

NASA Astrophysics Data System (ADS)

We applied a newly developed technique of the DAOSD (Double Asynchronous Orthogonal Sample Design) approach to probe weak coordination between Co2+ ions and acetone. Subtle spectral variation on the carbonyl band of acetone and d-d transition band are revealed via cross peaks of 2D asynchronous spectra generated by using the DAOSD approach. These results suggest that coordination occur between cobalt ions and the carbonyl group of acetone. To confirm whether coordination occur between cobalt ions and acetone, EXAFS experiments are utilized. The EXAFS results reveal that a Co2+ is coordinated by six methanol molecules in anhydrous CoCl2/methanol solution. Upon addition of acetone in into the anhydrous CoCl2/methanol solution, the coordination number of Co2+ ion becomes four, and one coordinating oxygen atom is replaced by a chlorine atom. We infer that the decrease in coordination number of Co2+ ion is due to the participation of the carbonyl oxygen of acetone in the coordination since the size of acetone is larger than methanol. This result provides an alternative evidence to support the conclusion that Co2+ ions coordinate with acetone, which is separately obtained from the 2D asynchronous spectra generated by using the DAOSD approach.

Liu, Jun; Gao, Yunlong; Zheng, Lirong; Gao, Danqing; He, Anqi; Liu, Yuhai; Weng, Shifu; Zhao, Ying; Yang, Zhanlan; Yang, Limin; Wen, Xiaodong; Xu, Yizhuang; Noda, Isao; Wu, Jinguang

2014-07-01

438

Replacing Solvent Drying Technique for Nanometer Particle Preparation  

Microsoft Academic Search

A prepration technique for nanometer particles, namely the replacing solvent drying technique, was developed. The main process of the technique including replacement of water in gel with special organic solvent and the removal of the solvent by distillation. No collapse of gel structure took place because of low interface tension between water and the solvent as well as low surface

Z. S. Hu; J. X. Dong; G. X. Chen

1998-01-01

439

Solvent disperser for removing oil from sponge core  

Microsoft Academic Search

This patent describes method for dispersing solvent for use in determining the oil saturation of an earth formation by means of sponge coring, comprising: (a) receiving solvent dripping downwardly, and (b) conducting the received solvent by means of capillary action to an application zone located and dimensioned for passing such solvent to the sponge in a sponge core barrel.

Di Foggio

1988-01-01

440

SOLUBILITY CORRELATION OF [60]FULLERENE IN DIFFERENT SOLVENTS  

Microsoft Academic Search

The solubility of [60]fullerene in various solvents has been correlated to the molar volume ratio of [60]fullerene and the respective solvent. The solubility varies linearly with the molar volume for the alcohol series and the heteroatom containing solvents, though specific interactions of the charge transfer type seem to dominate in the case of aromatic hydrocarbons and the halogenated solvents. The

C. N. Murthy; K. E. Geckeler

2001-01-01

441

Molecular design of solvents for liquid extraction based on UNIFAC  

Microsoft Academic Search

Cm the basis of the UNIFAC group contribution method, it is proposed to syn- thesize molecular structures with specific solvent properties for the separation of aromatic and paraffinic hydrocarbons. The potential solvents were studied with regard to their solvent power, selectivity and binoclal c-e on the basis of UNIFAC predictions. In this way good potential solvents were found. In gen-

R. GANI; E. A. BRIGNOLE

1983-01-01

442

Information Technology as Coordination Infrastructure  

Microsoft Academic Search

Business information technology is traditionally viewed as information provision technology. In this view, organizations use their IT to implement databases that provide people with information when they want it. This view is persistent even though information provision is never an end in itself but always has the further purpose to support the coordination of activities of people. The role if

R. J. Wieringa

2006-01-01

443

Coordination in Split Award Auctions  

Microsoft Academic Search

The authors analyze split award procurement auctions in which a buyer divides full production between two suppliers or awards all production to a single supplier, and suppliers have private cost information. An intriguing feature of split awards is that the equilibrium bids are implicitly coordinated. Because a split award price is the sum of offered split prices, each supplier can

James J Anton; Dennis A Yao

1992-01-01

444

Co-ordinated Classroom Lectures.  

ERIC Educational Resources Information Center

From a series of lectures, a selection of eight are oriented principally toward the biologically developing child, and the physiological operations in visual process. The numbered lectures are--(1) The Coordinated Classroom, its Philosophy and Principles, (2) An Outline of a Biological Point of View, (3) The Evolution of Structure--despite man's…

Harmon, Darell Boyd

445

Center for coordination science, MIT  

Microsoft Academic Search

The costs and capabilities of information technology are improving by orders of magnitude every decade, but we are only beginning to understand the opportunities these changes provide for new ways of organizing human activity and new kinds of technology to help people work together. The new MIT Center for Coordination Science conducts multidisciplinary research to help understand these possibilities better.

T. W. Malone

1989-01-01

446

Coordination Chemistry of Metal Surfaces.  

National Technical Information Service (NTIS)

In coordinately unsaturated molecular metal complexes, carbon-hydrogen bonds of the peripheral ligands may, if the stereochemistry allows, closely approach a metal center so as to develop a three-center two-electron bond between the carbon, the hydrogen, ...

E. L. Muetterties

1980-01-01

447

BURN DATA COORDINATING CENTER (BDCC)  

EPA Science Inventory

The Burn Data Coordinating Center (BDCC) began collecting data in 1994 and is currently the largest burn database in the country. Pediatric burn data was added in 1998. The BMS database contains over 2,800 cases supporting clinical research and research on outcomes including empl...

448

Coordinate Dependence of Variability Analysis  

Microsoft Academic Search

Analysis of motor performance variability in tasks with redundancy affords insight about synergies underlying central nervous system (CNS) control. Preferential distribution of variability in ways that minimally affect task performance suggests sophisticated neural control. Unfortunately, in the analysis of variability the choice of coordinates used to represent multi-dimensional data may profoundly affect analysis, introducing an arbitrariness which compromises its conclusions.

Dagmar Sternad; Se-Woong Park; Hermann Müller; Neville Hogan

2010-01-01

449

USGS ShakeOut Coordinators  

USGS Multimedia Gallery

Some of the 2008 USGS Great Southern California ShakeOut earthquake scenario coordinators taken at the Beckman Auditorium on the Caltech campus. Back: (L to R) Chuck Real, Anne Wein, Keith Porter, Kim Shoaf, Ken Hudnut, Jim Goltz, Hope Seligson, Dan Ponti, Jerry Treiman, Sue Perry Front: Lucy ...

2008-12-03

450

Sensory Coordination of Insect Flight.  

National Technical Information Service (NTIS)

This is the final report of a project that studied antennal positioning in moths and freely flying bees, location of odor sources in the fruit fly, coordination of wings and halters in the soldier fly, and landing behavior in the housefly.

S. Sane

2011-01-01

451

Can a franchise chain coordinate?  

Microsoft Academic Search

In today's business landscape, the familiar traditional corporation has been augmented by new species, such as joint ventures, strategic alliances, and franchise chains. The properties of these new species, termed hybrid forms, are distinctly different from the traditional corporation. In this paper, we examine whether one hybrid form, the franchise chain, can coordinate elements of the marketing mix (price, quality,

Steven C. Michael

2002-01-01

452

Consideration in GIS insulation coordination.  

National Technical Information Service (NTIS)

Analysis of electrical system failures reveals that many are caused by insulation breakdowns due to overvoltages. The problem of insulation co-ordination is then one of the most important aspects in the design of an electrical system. Insulation co-ordina...

A. Bargigia

1990-01-01

453

C[squared] = Creative Coordinates  

ERIC Educational Resources Information Center

"C[squared] = Creative Coordinates" is an engaging group of tasks that fosters the integration of mathematics and art to create meaningful understanding. The project lets students illustrate of find an image, then plot points to map their design on a grid. The project usually takes about a week to complete. When it is finished, students who are…

McHugh, Shelley R.

2007-01-01

454

The Coordination of Unlike Categories.  

ERIC Educational Resources Information Center

Argues that the account of coordination of unlike categories ought to be unified with the account of feature neutralization under phonological identity. Further argues that this unified account ought not be couched in terms of string of features, but rather in terms of the logic of categories. Study concludes with a discussion of the interactions…

Bayer, Samuel

1996-01-01

455

Coordinated Home Care Training Manual.  

ERIC Educational Resources Information Center

This manual is intended as a source of information and assistance in the planning, organization, implementation, and evaluation of home care programs. There are ten major sections: (1) Introduction (review of the history of home care and definition of pertinent terms), (2) Program Planning, (3) Organizational Structure, (4) Coordination and…

Michigan Univ., Ann Arbor. Home Care Training Center.

456

The plane with parallel coordinates  

Microsoft Academic Search

By means ofParallel Coordinates planar “graphs” of multivariate relations are obtained. Certain properties of the relationship correspond tothe geometrical properties of its graph. On the plane a point ?? line duality with several interesting properties is induced. A new duality betweenbounded and unbounded convex sets and hstars (a generalization of hyperbolas) and between Convex Unions and Intersections is found. This

Alfred Inselberg

1985-01-01

457

Archimedes' Principle in General Coordinates  

ERIC Educational Resources Information Center

Archimedes' principle is well known to state that a body submerged in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the body. Herein, Archimedes' principle is derived from first principles by using conservation of the stress-energy-momentum tensor in general coordinates. The resulting expression for the force is…

Ridgely, Charles T.

2010-01-01

458

ON THE EFFECT OF A WEAK INTERPLANETARY MAGNETIC FIELD ON THE INTERACTION BETWEEN THE SOLAR WIND AND THE GEOMAGNETIC FIELD  

Microsoft Academic Search

the presence of a weak interplanetary magnetic field may lead to the ; formation of a collision-free shock wave upstream from the boundary of the ; geomagnetic field and to a transition region characterized by an irregular ; magnetic field in the intervening space. Previous calculations of the ; coordinates of the shock wave are improved upon by application of

John R. Spreiter; Wm. Prichard Jones

1963-01-01

459

Reactive Tuple Spaces for Mobile Agent Coordination  

Microsoft Academic Search

Mobile active computational entities introduce peculiar problems in the coordination o f distributed app lication components. The paper s urveys s everal coordination models for mobile agent applications and outlines the advantages of uncoupled coordination models based on reactive blackboards. On this base, the paper presents the design and the implementation o f the MARS system, a coordination tool for

Giacomo Cabri; Letizia Leonardi; Franco Zambonelli

1998-01-01

460

Coordination polymerization of heterocyclic and heterounsaturated monomers  

Microsoft Academic Search

Polymerizations and copolymerizations of non-hydrocarbon monomers, such as heterocyclic and heterounsaturated monomers, in the presence of coordination catalysts constitute a distinct group of coordination polymerization processes which differ essentially from the coordination polymerization of unsaturated hydrocarbon monomers in terms of the kinds of catalyst applicable and the polymerization mechanism. While the coordination polymerization and copolymerization of numerous hydrocarbon monomers with

Witold Kuran

1998-01-01

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