Resource Type

States

Design and Performance of the Matching Beamline Between the Bnl Ebis and an Rfq. (open access)

Design and Performance of the Matching Beamline Between the Bnl Ebis and an Rfq.

A part of a new EBIS-based heavy ion preinjector, the low energy beam transport (LEBT) section between the high current EBIS and the RFQ is a challenging design, because it must serve many functions. In addition to the requirement to provide an efficient matching between the EBIS and the RFQ, this line must serve as a fast ''switchyard'', allowing singly charged ions from external sources to be transported into the EBIS trap region, and extracted, highly charged ions to be deflected to off-axis diagnostics (time-of-flight or emittance). The space charge of the 5-10 mA extracted heavy ion beam is a major consideration in the design, and the space charge force varies for different ion beams having Q/m from 1-0.16. The line includes electrostatic lenses, spherical and parallel-plate deflectors, magnetic solenoid, and diagnostics for measuring current, charge state distributions, emittance, and profile. A prototype of this beamline has been built, and results of tests are presented.
Date: June 25, 2007
Creator: Alessi, J.; Beebe, E.; Brodowski, J.; Kponou, A.; Okamura, M.; Pikin, A. et al.
System: The UNT Digital Library
Light-Front Holography and Hadronization at the Amplitude Level (open access)

Light-Front Holography and Hadronization at the Amplitude Level

The correspondence between theories in anti-de Sitter space and conformal field theories in physical space-time leads to an analytic, semiclassical model for strongly-coupled QCD which has scale invariance at short distances and color confinement at large distances. Light-front holography is a remarkable feature of AdS/CFT: it allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates and the behavior of the QCD coupling in the infrared. We suggest that the spatial support of QCD condensates is restricted to the interior of hadrons, since they arise due to the interactions of confined quarks and gluons. Chiral symmetry is thus broken in a limited domain of size 1=m{sub {pi}} in analogy to the limited physical extent of superconductor phases. A new method for computing the hadronization of quark and gluon jets at the amplitude level, an event amplitude generator, is outlined.
Date: July 25, 2008
Creator: Brodsky, Stanley J.; de Teramond, Guy & Shrock, Robert
System: The UNT Digital Library
Heavy ion fusion science research for high energy density physics and fusion applications (open access)

Heavy ion fusion science research for high energy density physics and fusion applications

During the past two years, the U.S. heavy ion fusion science program has made significant experimental and theoretical progress in simultaneous transverse and longitudinal beam compression, ion-beam-driven warm dense matter targets, high brightness beam transport, advanced theory and numerical simulations, and heavy ion target designs for fusion. First experiments combining radial and longitudinal compression of intense ion beams propagating through background plasma resulted in on-axis beam densities increased by 700X at the focal plane. With further improvements planned in 2007, these results will enable initial ion beam target experiments in warm dense matter to begin next year at LBNL. We are assessing how these new techniques apply to low-cost modular fusion drivers and higher-gain direct-drive targets for inertial fusion energy.
Date: June 25, 2007
Creator: Logan, B. G.; Bieniosek, F. M.; Barnard, J. J.; Cohen, R. H.; Coleman, J. E.; Davidson, R. C. et al.
System: The UNT Digital Library
Vibration Measurements to Study the Effect of Cryogen Flow in Superconducting Quadrupole. (open access)

Vibration Measurements to Study the Effect of Cryogen Flow in Superconducting Quadrupole.

The conceptual design of compact superconducting magnets for the International Linear Collider final focus is presently under development. A primary concern in using superconducting quadrupoles is the potential for inducing additional vibrations from cryogenic operation. We have employed a Laser Doppler Vibrometer system to measure the vibrations in a spare RHIC quadrupole magnet under cryogenic conditions. Some preliminary results of these studies were limited in resolution due to a rather large motion of the laser head as well as the magnet. As a first step towards improving the measurement quality, a new set up was used that reduces the motion of the laser holder. The improved setup is described, and vibration spectra measured at cryogenic temperatures, both with and without helium flow, are presented.
Date: June 25, 2007
Creator: He, P.; Anerella, M.; Aydin, S.; Ganetis, G.; Harrison, M.; Jain, A. et al.
System: The UNT Digital Library
Metabolic engineering of Saccharomyces cerevisiae for the production of n-butanol (open access)

Metabolic engineering of Saccharomyces cerevisiae for the production of n-butanol

BackgroundIncreasing energy costs and environmental concerns have motivated engineering microbes for the production of ?second generation? biofuels that have better properties than ethanol.Results& ConclusionsSaccharomyces cerevisiae was engineered with an n-butanol biosynthetic pathway, in which isozymes from a number of different organisms (S. cerevisiae, Escherichia coli, Clostridium beijerinckii, and Ralstonia eutropha) were substituted for the Clostridial enzymes and their effect on n-butanol production was compared. By choosing the appropriate isozymes, we were able to improve production of n-butanol ten-fold to 2.5 mg/L. The most productive strains harbored the C. beijerinckii 3-hydroxybutyryl-CoA dehydrogenase, which uses NADH as a co-factor, rather than the R. eutropha isozyme, which uses NADPH, and the acetoacetyl-CoA transferase from S. cerevisiae or E. coli rather than that from R. eutropha. Surprisingly, expression of the genes encoding the butyryl-CoA dehydrogenase from C. beijerinckii (bcd and etfAB) did not improve butanol production significantly as previously reported in E. coli. Using metabolite analysis, we were able to determine which steps in the n-butanol biosynthetic pathway were the most problematic and ripe for future improvement.
Date: November 25, 2008
Creator: Steen, EricJ.; Chan, Rossana; Prasad, Nilu; Myers, Samuel; Petzold, Christopher; Redding, Alyssa et al.
System: The UNT Digital Library
Neutron Soft Errors in Xilinx FPGAs at Lawrence Berkeley National Laboratory (open access)

Neutron Soft Errors in Xilinx FPGAs at Lawrence Berkeley National Laboratory

The LBNL 88-Inch Cyclotron offers broad-spectrum neutrons for single event effects testing. We discuss results from this beamline for neutron soft upsets in Xilinx Virtex-4 and -5 field-programmable-gate-array (FPGA) devices.
Date: July 25, 2008
Creator: George, Jeffrey S.; Koga, Rocky & McMahan, Margaret A.
System: The UNT Digital Library
Executive Summary of the Workshop on Polarization and Beam Energy Measurements at the ILC (open access)

Executive Summary of the Workshop on Polarization and Beam Energy Measurements at the ILC

This note summarizes the results of the 'Workshop on Polarization and Beam Energy Measurements at the ILC', held at DESY (Zeuthen) April 9-11 2008. The topics for the workshop included (1) physics requirements, (2) polarized sources and low energy polarimetry, (3) BDS polarimeters, (4) BDS energy spectrometers, and (5) physics-based measurements of beam polarization and beam energy from collider data. Discussions focused on the current ILC baseline program as described in the Reference Design Report (RDR), which includes physics runs at beam energies between 100 and 250 GeV, as well as calibration runs on the Z-pole. Electron polarization of P{sub e{sup -}} {approx}> 80% and positron polarization of P{sub e{sup +}} {approx}> 30% are part of the baseline configuration of the machine. Energy and polarization measurements for ILC options beyond the baseline, including Z-pole running and the 1 TeV energy upgrade, were also discussed.
Date: July 25, 2008
Creator: Aurand, B.; Bailey, I.; Bartels, C.; Blair, G.; Brachmann, A.; Clarke, J. et al.
System: The UNT Digital Library
Primary Quantum Conversion in Photosynthesis (open access)

Primary Quantum Conversion in Photosynthesis

None
Date: August 25, 1962
Creator: Calvin, Melvin & Androes, G. M.
System: The UNT Digital Library
The Use of Small Coolers in a Magnetic Field (open access)

The Use of Small Coolers in a Magnetic Field

Small 4 K coolers are used to cool superconducting magnets.These coolers are usually used with high temperature suerconductor (HTS)leads. In most cases, magnet is shielded with iron or active shieldcoils. Thus the field at the cooler is low. There are instances when thecooler must be in a magnetic field. Gifford McMahon (GM) coolers or pulsetube coolers are commercially available to cool the magnets. This paperwill discuss how the two types of coolers are affected by the straymagnetic field. Strategies for using coolers on magnets that generatestray magnetic fields are discussed.
Date: July 25, 2007
Creator: Green, Michael A. & Witte, Holger
System: The UNT Digital Library
Study of the Decay Ds+ to K+K-e+nu (open access)

Study of the Decay Ds+ to K+K-e+nu

Using 214 fb{sup -1} of data recorded by the BABAR detector at the PEPII electron-positron collider, they study the decay D{sub s}{sup +} {yields} K{sup +}K{sup -}e{sup +}{nu}{sub e}. Except for a small S-wave contribution, the events with K{sup +}K{sup -} masses in the range 1.01-1.03 GeV/c{sup 2} correspond to {phi} mesons. For D{sub s}{sup +} {yields} {phi}e{sup +}{nu}{sub e} decays, they measure the relative normalization of the Lorentz invariant form factors at q{sup 2} = 0, r{sub V} = V(0)/A{sub 1}(0) = 1.849 {+-} 0.060 {+-} 0.095, r{sub 2} = A{sub 2}(0)/A{sub 1}(0) = 0.763 {+-} 0.071 {+-} 0.065 and the pole mass of the axial-vector form factors m{sub A} = (2.28{sub -0.18}{sup +0.23} {+-} 0.18) GeV/c{sup 2}. Within the same K{sup +}K{sup -} mass range, they also measure the relative branching fractions {Beta}(D{sub s}{sup +} {yields} K{sup +}K{sup -}e{sup +}{nu}{sub e})/{Beta}(D{sub s}{sup +} {yields} K{sup +}K{sup -}{pi}{sup +}) - 0.558 {+-} 0.007 {+-} 0.016, from which they obtain the total branching fraction {Beta}(D{sub s}{sup +} {yields} {phi}e{sup +}{nu}{sub e}) = (2.61 {+-} 0.03 {+-} 0.08 {+-} 0.15) x 10{sup -2}. By comparing this value with the predicted decay rate, they extract A{sub 1}(0) = 0.607 {+-} 0.011 {+-} …
Date: July 25, 2008
Creator: Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E. et al.
System: The UNT Digital Library
A Variation of the F-Test for Determining Statistical Relevance ofParticular Parameters in EXAFS Fits (open access)

A Variation of the F-Test for Determining Statistical Relevance ofParticular Parameters in EXAFS Fits

A general problem when fitting EXAFS data is determining whether particular parameters are statistically significant. The F-test is an excellent way of determining relevancy in EXAFS because it only relies on the ratio of the fit residual of two possible models, and therefore the data errors approximately cancel. Although this test is widely used in crystallography (there, it is often called a 'Hamilton test') and has been properly applied to EXAFS data in the past, it is very rarely applied in EXAFS analysis. We have implemented a variation of the F-test adapted for EXAFS data analysis in the RSXAP analysis package, and demonstrate its applicability with a few examples, including determining whether a particular scattering shell is warranted, and differentiating between two possible species or two possible structures in a given shell.
Date: July 25, 2006
Creator: Downward, L.; Booth, C.H.; Lukens, W.W. & Bridges, F.
System: The UNT Digital Library
Preparation and Reactions of Base-FreeBis(1,2,4-tri-tert-butylcyclopentadienyl)uranium Oxide, Cp'2UO (open access)

Preparation and Reactions of Base-FreeBis(1,2,4-tri-tert-butylcyclopentadienyl)uranium Oxide, Cp'2UO

Reduction of the uranium metallocene,[eta5-1,2,4-(Me3C)3C5H2]2UCl2 (1), Cp'2UCl2, in the presence of2,2'-bipyridyl and sodium naphthalene gives the dark green metallocenecomplex, Cp'2U(bipy) (6), which reacts with p-tolylazide orpyridine-N-oxide to give Cp'2U=N(p-tolyl) (7) or Cp'2U(O)(py) (8),respectively. The Lewis acid, BPh3, precipitates Ph3B(py) and gives thebase-free oxo, Cp'2UO (10), which crystallizes from pentane. Theoxometallocene 10 behaves as a nucleophile with Me3SiX reagents but itdoes not exhibit cycloaddition behavior with acetylenes, suggesting thatthe polar resonance structure, Cp'2U+-O- dominates the double bondresonance structure Cp'2U=O.
Date: May 25, 2005
Creator: Zi, Guofu; Werkema, Evan L.; Walter, Marc D.; Gottfriedsen,Jochen P. & Andersen, Richard A.
System: The UNT Digital Library
Isotopic mass-dependence of noble gas diffusion coefficients inwater (open access)

Isotopic mass-dependence of noble gas diffusion coefficients inwater

Noble gas isotopes are used extensively as tracers inhydrologic and paleoclimatic studies. These applications requireknowledge of the isotopic mass (m) dependence of noble gas diffusioncoefficients in water (D), which has not been measured but is estimatedusing experimental D-values for the major isotopes along with an untestedrelationship from kinetic theory, D prop m-0.5. We applied moleculardynamics methods to determine the mass dependence of D for four noblegases at 298 K, finding that D prop m-beta with beta<0.2, whichrefutes the kinetic theory model underlying all currentapplications.
Date: June 25, 2007
Creator: Bourg, I.C. & Sposito, G.
System: The UNT Digital Library
Spatial Dependence of Condensates in Strongly Coupled Gauge Theories (open access)

Spatial Dependence of Condensates in Strongly Coupled Gauge Theories

We analyze quark and gluon condensates in quantum chromodynamics. We suggest that these are localized inside hadrons, because the particles whose interactions are responsible for them are confined within these hadrons. This can explain the results of recent studies of gluon condensate contributions to vacuum correlators. We also give a general discussion of condensates in asymptotically free vectorial and chiral gauge theories.
Date: March 25, 2008
Creator: Brodsky, Stanley J.; /SLAC /SUNY, Stony Brook; Shrock, Robert & /SUNY, Stony Brook
System: The UNT Digital Library
End-to-End Simulations for the Ebis Preinjector. (open access)

End-to-End Simulations for the Ebis Preinjector.

The EBIS Project at Brookhaven National Laboratory is in the second year of a four-year project. It will replace the Tandem Van de Graaff accelerators with an Electron Beam Ion Source, an RFQ, and one IH Linac cavity, as the heavy ion preinjector for the Relativistic Heavy Ion Collider (RHIC), and for the NASA Space Radiation Laboratory (NSRL). The preinjector will provide all ions species, He to U, (Q/m &gt;0.16) at 2 MeV/amu at a repetition rate of 5 Hz, pulse length of 10-40 {micro}s, and intensities of {approx}2.0 mA. End-to-end simulations (from EBIS to the Booster injection) as well as error sensitivity studies will be presented and physics issues will be discussed.
Date: June 25, 2007
Creator: Raparia, D.; Alessi, J.; Kponou, A.; Pikin, A.; Ritter, J.; Minaev, S. et al.
System: The UNT Digital Library
Optical Faraday Cup for Heavy Ion Beams (open access)

Optical Faraday Cup for Heavy Ion Beams

We have been using alumina scintillators for imaging beams in heavy-ion beam fusion experiments in 2 to 4 transverse dimensions [1]. The scintillator has a limited lifetime under bombardment by the heavy ion beams. As a possible replacement for the scintillator, we are studying the technique of imaging the beam on a gas cloud. A gas cloud for imaging the beam may be created on a solid hole plate placed in the path of the beam, or by a localized gas jet. It is possible to image the beam using certain fast-quenching optical lines that closely follow beam current density and are independent of gas density. We describe this technique and show preliminary experimental data. This approach has promise to be a new fast beam current diagnostic on a nanosecond time scale.
Date: June 25, 2007
Creator: Bieniosek, Frank; Bieniosek, F. M.; Eylon, S.; Roy, P. K. & Yu, S. S.
System: The UNT Digital Library
Plasma Lens for Us Based Super Neutrino Beam at Either Fnal or Bnl. (open access)

Plasma Lens for Us Based Super Neutrino Beam at Either Fnal or Bnl.

The plasma lens concept is examined as an alternative to focusing horns and solenoids for a neutrino beam facility. The concept is based on a combined high-current lens/target configuration. Current is fed at an electrode located downstream from the beginning of the target where pion capturing is needed. The current is carried by plasma outside the target. A second plasma lens section, with an additional current feed, follows the target. The plasma is immersed in a relatively small solenoidal magnetic field to facilitate its current profile shaping to optimize pion capture. Simulations of the not yet fully optimized configuration yielded a 25% higher neutrino flux at a detector situated at 3 km from the target than the horn system for the entire energy spectrum and a factor of 2.47 higher flux for neutrinos with energy larger than 3 GeV. A major advantage of plasma lenses is in background reduction. In anti-neutrino operation, neutrino background is reduced by a factor of close to 3 for the whole spectrum, and for and for energy larger than 3 GeV, neutrino background is reduced by a factor of 3.6. Plasma lenses have additional advantages: larger axial currents, high signal purity: minimal neutrino background in …
Date: June 25, 2007
Creator: Hershcovitch, A.; Weng, W.; Diwan, M.; Gallardo, J.; Kirk, H.; Johnson, B. et al.
System: The UNT Digital Library
Membrane proteomics of phagosomes suggests a connection to autophagy (open access)

Membrane proteomics of phagosomes suggests a connection to autophagy

Phagocytosis is the central process by which macrophage cellsinternalize and eliminate infectious microbes as well as apoptoticcells. During maturation, phagosomes containing engulfed particlesfuse with various endosomal compartments through theaction of regulatory molecules on the phagosomal membrane. Inthis study, we performed a proteomic analysis of the membranefraction from latex bead-containing (LBC) phagosomes isolatedfrom macrophages. The profile, which comprised 546 proteins,suggests diverse functions of the phagosome and potential connectionsto secretory processes, toll-like receptor signaling, andautophagy. Many identified proteins were not previously knownto reside in the phagosome. We characterized several proteins inLBC phagosomes that change in abundance on induction of autophagy,a process that has been previously implicated in the hostdefense against microbial pathogens. These observations suggestcrosstalk between autophagy and phagocytosis that may be relevantto the innate immune response of macrophages.
Date: November 25, 2008
Creator: Shui, Wenqing; Sheu, Leslie; Liu, Jun; Smart, Brian; Petzold, Christopher J.; Hsieh, Tsung-yen et al.
System: The UNT Digital Library
Electron-Cloud Build-Up Simulations for the FNAL Main Injector (open access)

Electron-Cloud Build-Up Simulations for the FNAL Main Injector

We present a summary on ongoing simulation results for the electron-cloud (EC) buildup in the context of the proposed FNAL Main Injector (MI) intensity upgrade effort [1]. Most of the results presented here are for the field-free region at the location of the retarding field analyzer (RFA) electron detector [2-4]. The primary input variable we exercise is the peak secondary electron yield (SEY) {delta}{sub max}, which we let vary in the range 1.2 {le} {delta}{sub max} {le} 1.7. By combining our simulated results for the electron flux at the vacuum chamber wall with the corresponding RFA measurements we infer that 1.25 {approx}&lt; {delta}{sub max} {approx}&lt; 1.35 at this location. From this piece of information we estimate features of the EC distribution for various fill patterns, including the average electron number density n{sub e}. We then compare the behavior of the EC for a hypothetical RF frequency f{sub RF} = 212 MHz with the current 53 MHz for a given total beam population N{sub tot}. The density n{sub e} goes through a clear threshold as a function of N{sub tot} in a field-free region. As expected, the higher frequency leads to a weaker EC effect: the threshold in N{sub tot} is …
Date: August 25, 2008
Creator: Furman, Miguel .A.
System: The UNT Digital Library
Numerical Study of Coulomb Scattering Effects on Electron Beamfrom a Nano-Tip (open access)

Numerical Study of Coulomb Scattering Effects on Electron Beamfrom a Nano-Tip

Nano-tips with high acceleration gradient around the emission surface have been proposed to generate high brightness beams. However, due to the small size of the tip, the charge density near the tip is very high even for a small number of electrons. The stochastic Coulomb scattering near the tip can degrade the beam quality and cause extra emittance growth and energy spread. In the paper, we present a numerical study of these effects using a direct relativistic N-body model. We found that emittance growth and energy spread, due to Coulomb scattering, can be significantly enhanced with respect to mean-field space-charge calculations.
Date: June 25, 2007
Creator: Qiang, Ji; Corlett, John N.; Lidia, Steven M.; Padmore, HowardA.; Wan, Weishi; Zholent, Andrew A. et al.
System: The UNT Digital Library
Performance of capillary discharge guided laser plasma wakefieldaccelerator (open access)

Performance of capillary discharge guided laser plasma wakefieldaccelerator

A GeV-class laser-driven plasma-based wakefield acceleratorhas been realized at the Lawrence Berkeley National Laboratory (LBNL).The device consists of the 40TW high repetition rate Ti:sapphire LOASISlaser system at LBNL and a gas-filled capillary discharge waveguidedeveloped at Oxford University. The operation of the capillary dischargeguided laser plasma wakefield accelerator with a capillaryof 225 mu mdiameter and 33 mm in length was analyzed in detail. The input intensitydependence suggests that excessive self-injection causes increased beamloading leading to broadband lower energy electron beam generation. Thetrigger versus laser arrival timing dependence suggests that the plasmachannel parameters can be tuned to reduce beam divergence.
Date: June 25, 2007
Creator: Nakamura, Kei; Esarey, Eric; Geddes, Cameron G. R.; Gonsalves, Anthony J.; Leemans, Wim P.; Panasenko, Dmitriy et al.
System: The UNT Digital Library
PROGRESS IN BEAM FOCUSING AND COMPRESSION FOR WARM-DENSE MATTER EXPERIMENTS (open access)

PROGRESS IN BEAM FOCUSING AND COMPRESSION FOR WARM-DENSE MATTER EXPERIMENTS

The Heavy-Ion Fusion Sciences Virtual National Laboratory is pursuing an approach to target heating experiments in the Warm Dense Matter regime, using spacecharge-dominated ion beams that are simultaneously longitudinally bunched and transversely focused. Longitudinal beam compression by large factors has beendemonstrated in the Neutralized Drift Compression Experiment (NDCX) with controlledramps and forced neutralization. Using an injected 30-mA K+ ion beam with initialkinetic energy 0.3 MeV, axial compression leading to ~;;50-fold current amplification andsimultaneous radial focusing to beam radii of a few mm have led to encouraging energy deposition approaching the intensities required for eV-range target heating experiments. We discuss the status of several improvements to our Neutralized Drift Compression Experiment and associated beam diagnostics that are under development to reach the necessary higher beam intensities, including: (1) greater axial compression via a longer velocity ramp using a new bunching module with approximately twice the available voltseconds; (2) improved centroid control via beam steering dipoles to mitigate aberrations in the bunching module; (3) time-dependent focusing elements to correct considerable chromatic aberrations; and (4) plasma injection improvements to establish a plasma density always greater than the beam density, expected to be&gt;1013 cm-3.
Date: September 25, 2008
Creator: Seidl, P. A.; Anders, A.; Bieniosek, F. M.; Barnard, J. J.; Calanog, J.; Chen, A. X. et al.
System: The UNT Digital Library
A method for obtaining three-dimensional computation equilibrium of non-neutral plasmas using WARP (open access)

A method for obtaining three-dimensional computation equilibrium of non-neutral plasmas using WARP

Computer simulation studies of the stability and transport properties of trapped non-neutral plasmas require the numerical realization of a three-dimensional plasma distribution. This paper presents a new numerical method for obtaining, without an explicit model for physical collisions in the code, a low noise three-dimensional computational equilibrium distribution. This requires both the loading of particles into an idealized distribution and the relaxation from that distribution toward an approximate numerical equilibrium. The equilibrium can then be modified through a slow change of system parameters, to generate other equilibria. In the present work we apply this method to a UC Berkeley experiment on electron confinement in magnetic geometries appropriate for the ALPHA anti-hydrogen experiment, using the three-dimensional Particle-In-Cell code WARP. WARP's guiding center mover and its option to switch between different solvers during a simulation are highly valuable because they speed up the simulations; they enable the practical use of the new technique for generating numerical equilibrium states of trapped nonneutral plasmas.
Date: March 25, 2006
Creator: Wurtele, J.; Wurtele, J.; Friedman, A.; Grote, D. P.; Vay, J. L. & Gomberoff, K.
System: The UNT Digital Library
Physicochemical properties and toxicities of hydrophobicpiperidinium and pyrrolidinium ionic liquids (open access)

Physicochemical properties and toxicities of hydrophobicpiperidinium and pyrrolidinium ionic liquids

Some properties are reported for hydrophobic ionic liquids (IL) containing 1-methyl-1-propyl pyrrolidinium [MPPyrro]{sup +}, 1-methyl-1-butyl pyrrolidinium [MBPyrro]{sup +}, 1-methyl-1-propyl piperidinium [MPPip]{sup +}, 1-methyl-1-butyl piperidinium [MBPip]{sup +}, 1-methyl-1-octylpyrrolidinium [MOPyrro]{sup +} and 1-methyl-1-octylpiperidinium [MOPip]{sup +} cations. These liquids provide new alternatives to pyridinium and imidazolium ILs. High thermal stability of an ionic liquid increases safety in applications like rechargeable lithium-ion batteries and other electrochemical devices. Thermal properties, ionic conductivities, viscosities, and mutual solubilities with water are reported. In addition, toxicities of selected ionic liquids have been measured using a human cancer cell-line. The ILs studied here are sparingly soluble in water but hygroscopic. We show some structure-property relationships that may help to design green solvents for specific applications. While ionic liquids are claimed to be environmentally-benign solvents, as yet few data have been published to support these claims.
Date: June 25, 2007
Creator: Salminen, Justin; Papaiconomou, Nicolas; Kumar, R. Anand; Lee,Jong-Min; Kerr, John; Newman, John et al.
System: The UNT Digital Library