bluuebunny/crossref_metadata_2025 huggingface dataset:
Excess-conductivity analysis of Mg- and Be-doped polycrystalline Cu0.5Tl0.5Ba2Ca1.5M1.5Cu4O12−δ (M=, Be, Mg) superconductors
Authors: Hassan Najmul , Shabbir Babar , Khan Nawazish A.
Published: April 2009

High-resolution electrical resistivity ρ(T) data of as-prepared and O2-annealed Cu0.5Tl0.5Ba2Ca1.5M1.5Cu4O12−δ (M=0, Be, Mg) superconductor samples have been taken for investigating critically the superconducting fluctuations. Using the Aslamazov–Larkin (AL) and Lawrence–Doniach (LD) models of excess conductivity, several physical parameters of the models have been estimated. In all the as-prepared and oxygen postannealed samples one crossover temperature and two distinct exponents have been observed. The excess conductivity data of the as-prepared as well as O2-annealed undoped sample seem to fit well two-dimensional (2D), three-dimensional (3D) AL equations, but for Mg- and Be-doped and their respective oxygen annealed samples do not seem to fit well with 2DAL and 3DAL equations with one distinct crossover temperature. We observed two more critical regions: −4.86<ln(ε)<−3.76 and −4.76<ln(ε)<−1.63 in the Mg- and Be-doped Cu0.5Tl0.5Ba2Ca1.5M1.5Cu4O12-δ (M=0, Be, Mg) samples, giving exponents of −0.37 and −0.79, respectively. The interlayer coupling strength J is found to increase with increased Mg or Be content and oxygen postannealing. The critical temperatures (Tc) varies from 99 to 116 K and the transition widths (ΔTc), estimated from dp/dT(T) plots by using the full width at half maximum of the peaks, come out to be lying between 1.91 and 6.28 K for all samples, indicating a sharp transition.
Resonant magnetohydrodynamic waves in high-beta plasmas
Authors: Ruderman M. S.
Published: April 2009

When a global magnetohydrodynamic (MHD) wave propagates in a weakly dissipative inhomogeneous plasma, the resonant interaction of this wave with either local Alfvén or slow MHD waves is possible. This interaction occurs at the resonant position where the phase velocity of the global wave coincides with the phase velocity of either Alfvén or slow MHD waves. As a result of this interaction a dissipative layer embracing the resonant position is formed, its thickness being proportional to R−1/3, where R⪢1 is the Reynolds number. The wave motion in the resonant layer is characterized by large amplitudes and large gradients. The presence of large gradients causes strong dissipation of the global wave even in very weakly dissipative plasmas. Very often the global wave motion is characterized by the presence of both Alfvén and slow resonances. In plasmas with small or moderate plasma beta β, the resonance positions corresponding to the Alfvén and slow resonances are well separated, so that the wave motion in the Alfvén and slow dissipative layers embracing the Alfvén and slow resonant positions, respectively, can be studied separately. However, when β≳R1/3, the two resonance positions are so close that the two dissipative layers overlap. In this case, instead of two dissipative layers, there is one mixed Alfvén-slow dissipative layer. In this paper the wave motion in such a mixed dissipative layer is studied. It is shown that this motion is a linear superposition of two motions, one corresponding to the Alfvén and the other to the slow dissipative layer. The jump of normal velocity across the mixed dissipative layer related to the energy dissipation rate is equal to the sum of two jumps, one that occurs across the Alfvén dissipative layer and the other across the slow dissipative layer.
Recovering four-component solutions by the inverse transformation of the infinite-order two-component wave functions
Authors: Barysz Maria , Mentel Łukasz , Leszczyński Jerzy
Published: April 2009

The two-component Hamiltonian of the infinite-order two-component (IOTC) theory is obtained by a unitary block-diagonalizing transformation of the Dirac–Hamiltonian. Once the IOTC spin orbitals are calculated, they can be back transformed into four-component solutions. The transformed four component solutions are then used to evaluate different moments of the electron density distribution. This formally exact method may, however, suffer from certain approximations involved in its numerical implementation. As shown by the present study, with sufficiently large basis set of Gaussian functions, the Dirac values of these moments are fully recovered in spite of using the approximate identity resolution into eigenvectors of the p2 operator.
Laboratory investigation of lateral dispersion within dense arrays of randomly distributed cylinders at transitional Reynolds number
Authors: Tanino Yukie , Nepf Heidi M.
Published: April 2009

Relative (effective) lateral dispersion of a passive solute was examined at transitional Reynolds numbers within a two-dimensional array of randomly distributed circular cylinders of uniform diameter d. The present work focuses on dense arrays, for which previously developed theory [Y. Tanino and H. M. Nepf, J. Fluid Mech. 600, 339 (2008)] implies that the asymptotic (long-time/long-distance) dispersion coefficient, when normalized by the mean interstitial fluid velocity, ⟨u¯⟩, and d, will only exhibit a weak dependence on Reynolds number, Red≡⟨u¯⟩d/ν, where ν is the kinematic viscosity. However, the advective distance required to reach asymptotic dispersion is expected to be controlled by pore-scale mixing, which is strongly Red-dependent prior to the onset of full turbulence. Laser-induced fluorescence was used to measure the time-averaged lateral concentration profiles of solute released continuously from a point source in arrays of solid volume fraction ϕ=0.20 and 0.35 at Red=48–120. Results are compared to previous measurements at higher Red. Lateral dispersion reaches the same rate as asymptotic dispersion in fully turbulent flow at x≈154d at (ϕ,Red)=(0.20,110–120) and at x≈87d at (ϕ,Red)=(0.35,300–390). In contrast, dispersion does not reach the fully turbulent flow limit at Red<100 within the range of x considered. Also, concentration profiles deviate further from a Gaussian distribution at ϕ=0.35 than at 0.20 for similar Red and xϕ/d. From these observations, it can be inferred that the pre-asymptotic regime extends farther downstream, in terms of the number of cylinders spanned, at lower Red and at larger ϕ.
Design and implementation of a system with a multielement thermopile for monitoring temperature of a plane
Authors: Li L. T. , Tsai C. F. , Young M. S.
Published: April 2009

In this paper, we report the design of a system equipped with a multielement thermopile for measuring the temperature of a given plane. We evaluate the performance of our measurement system, which comprises a microcontroller, an analog-to-digital converter, a liquid crystal display (LCD), light-emitting diodes (LEDs), a buzzer, laser pointers, and a rotary encoder. We use different types of display modes such as an LCD for displaying the measured temperature, LEDs which colors indicate the temperature range, and an RS-232 or a wireless interface that transmits the temperature values to be displayed as different colors on a PC screen. The buzzer/alarm in the system is activated when the threshold temperature is reached. The system is inexpensive, portable, and can be used for two-dimensional temperature measurements; further, its emissivity can be easily adjusted. The effective detection range of this system is from −20 to 115 °C, and the field of view is 41°×32°; the measurement error is confined to ±1 °C. The experimental results demonstrate the effectiveness of the system in monitoring the temperature of a remote plane. Hence, it is possible to identify a hot spot that occurred in the electrical heating equipment or a smoldering source hidden in upholstery.
Approximating quantum many-body intermolecular interactions in molecular clusters using classical polarizable force fields
Authors: Beran Gregory J. O.
Published: April 2009

Many-body intermolecular interaction expansions provide a promising avenue for the efficient quantum mechanical treatment of molecular clusters and condensed-phase systems, but the computationally expensive three-body and higher terms are often nontrivial. When polar molecules are involved, these many-body terms are typically dominated by electrostatic induction effects, which can be approximated relatively easily. We demonstrate an accurate and inexpensive hybrid quantum/classical model in which one- and two-body interactions are computed quantum mechanically, while the many-body induction effects are approximated with a simple classical polarizable force field. Whereas typical hybrid quantum/classical models partition a system spatially into distinct quantum and classical regions, the model demonstrated here partitions based on the order in the many-body interaction series. This enables a spatially homogeneous treatment of the entire system, which could prove advantageous in studying a wide range of condensed-phase molecular systems.
Broadband electromagnetic response and ultrafast dynamics of few-layer epitaxial graphene
Authors: Choi H. , Borondics F. , Siegel D. A. , Zhou S. Y. , Martin M. C. , Lanzara A. , Kaindl R. A.
Published: April 2009

We study the broadband optical conductivity and ultrafast carrier dynamics of epitaxial graphene in the few-layer limit. Equilibrium spectra of nominally buffer, monolayer, and multilayer graphene exhibit significant terahertz and near-infrared absorption, consistent with a model of intra- and interband transitions in a dense Dirac electron plasma. Nonequilibrium terahertz transmission changes after photoexcitation are shown to be dominated by excess hole carriers, with a 1.2 ps monoexponential decay that reflects the minority-carrier recombination time.
Experimental observation of mode-selective anticrossing in surface-plasmon-coupled metal nanoparticle arrays
Authors: Ghoshal Amitabh , Divliansky Ivan , Kik Pieter G.
Published: April 2009

Surface plasmon excitation using resonant metal nanoparticles is studied experimentally. Geometry dependent reflection measurements reveal the existence of several optical resonances. Strong coupling of the in-plane nanoparticle plasmon resonance and propagating plasmons is evident from clear anticrossing behavior. Reflection measurements at high numerical aperture demonstrate the excitation of surface plasmons via out-of-plane particle polarization. The thus excited plasmons do not exhibit anticrossing in the considered frequency range. The results are explained in terms of the known surface plasmon dispersion relation and the anisotropic frequency dependent nanoparticle polarizability. These findings are important for applications utilizing surface-coupled nanoparticle plasmon resonances.
Room temperature free carrier tunneling in dilute nitride based quantum well - quantum dot tunnel injection system for 1.3 μm
Authors: Rudno-Rudziński W. , Sęk G. , Ryczko K. , Syperek M. , Misiewicz J. , Semenova E. S. , Lemaitre A. , Ramdane A.
Published: April 2009

We present optical studies of quantum dot tunnel injection structures for 1.3 μm emission with an InGaAsN quantum well injector. Photoreflectance spectroscopy supported by effective mass calculations within the band anticrossing model has been used to identify the optical transitions. Based on that, an evidence of the tunneling from the injector well to the dots could be detected by photoluminescence excitation up to the free carrier regime at room temperature. The latter finds confirmation in shortened photoluminescence rise times, when compared to the injector-free quantum dot reference structure.
Evaluating the ability to form single crystal
Authors: Ye Xiang-Xi , Ming Chen , Hu Yun-Cheng , Ning Xi-Jing
Published: April 2009

Design of crystal materials requires predicting the ability of bulk materials to form single crystals, challenging current theories of material design. By introducing a concept of condensing potential (CP), it is shown via vast simulations of crystal growth for fcc (Ni, Cu, Al, Ar) and hcp (Mg), that materials with larger CP can grow into perfect single crystal more easily. Due to the simplicity of the calculation of CP, this method might prove a convenient way to evaluate the ability of materials to form single crystal.
Progress in physics and control of the resistive wall mode in advanced tokamaks
Authors: Liu Yueqiang , Chapman I. T. , Chu M. S. , Reimerdes H. , Villone F. , Albanese R. , Ambrosino G. , Garofalo A. M. , Gimblett C. G. , Hastie R. J. , Hender T. C. , Jackson G. L. , La Haye R. J. , Okabayashi M. , Pironti A. , Portone A. , Rubinacci G. , Strait E. J.
Published: April 2009

Self-consistent computations are carried out to study the stability of the resistive wall mode (RWM) in DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] plasmas with slow plasma rotation, using the hybrid kinetic-magnetohydrodynamic code MARS-K [Y. Q. Liu et al., Phys. Plasmas 15, 112503 (2008)]. Based on kinetic resonances between the mode and the thermal particle toroidal precession drifts, the self-consistent modeling predicts less stabilization of the mode compared to perturbative approaches, and with the DIII-D experiments. A simple analytic model is proposed to explain the MARS-K results, which also gives a qualitative interpretation of the recent experimental results observed in JT-60U [S. Takeji et al., Nucl. Fusion 42, 5 (2002)]. Our present analysis does not include the kinetic contribution from hot ions, which may give additional damping on the mode. The effect of particle collision is not included either. Using the CARMA code [R. Albanese et al., IEEE Trans. Magn. 44, 1654 (2008)], a stability and control analysis is performed for the RWM in ITER [R. Aymar et al., Plasma Phys. Controlled Fusion 44, 519 (2002)] steady state advanced plasmas, taking into account the influence of three-dimensional conducting structures.
Electron transfer dynamics: Zusman equation versus exact theory
Authors: Shi Qiang , Chen Liping , Nan Guangjun , Xu Ruixue , Yan YiJing
Published: April 2009

The Zusman equation has been widely used to study the effect of solvent dynamics on electron transfer reactions. However, application of this equation is limited by the classical treatment of the nuclear degrees of freedom. In this paper, we revisit the Zusman equation in the framework of the exact hierarchical equations of motion formalism, and show that a high temperature approximation of the hierarchical theory is equivalent to the Zusman equation in describing electron transfer dynamics. Thus the exact hierarchical formalism naturally extends the Zusman equation to include quantum nuclear dynamics at low temperatures. This new finding has also inspired us to rescale the original hierarchical equations and incorporate a filtering algorithm to efficiently propagate the hierarchical equations. Numerical exact results are also presented for the electron transfer reaction dynamics and rate constant calculations.
Enhanced ferromagnetism and ferroelectricity in multiferroic CuCr1−xNixO2
Authors: Luo Shijun , Wang K. F. , Li S. Z. , Dong X. W. , Yan Z. B. , Cai H. L. , Liu J.-M.
Published: April 2009

Polycrystalline CuCr1−xNixO2 is synthesized and its multiferrocity is characterized in order to enhance the ferromagnetism and ferroelectricity of CuCrO2-based multiferroics. At the optimized doping level x=0.05, we observe not only an enhancement of one order of magnitude in magnetization but also a remarkable increasing of polarization up to ∼50 μC/m2 from ∼35 μC/m2 of polycrystalline CuCrO2. It is argued that the Ni-doping may modulate the antiferromagnetic interactions between Cr3+ ions and probably induce the conical-like spin component responsible for the enhanced ferromagnetism.
Hydrodynamic friction coefficients of coated spherical particles
Authors: Cichocki B. , Felderhof B. U.
Published: April 2009

The complete set of hydrodynamic friction coefficients for a spherical particle coated with a porous layer and immersed in a viscous fluid is evaluated in analytic form. The coefficients allow the calculation of the flow disturbance caused by the coated particle for any incident flow which satisfies the creeping flow equations. The coefficients may be used for the evaluation of hydrodynamic pair interactions between coated spheres, as well as for the numerical calculation of many-sphere hydrodynamic interactions, and the calculation of transport properties of suspensions of coated spherical particles.
Frequently asked questions about global modeling
Authors: Letellier Christophe , Aguirre Luis A. , Freitas U. S.
Published: April 2009

When a global model is attempted from experimental data, some preprocessing might be required. Therefore it is only natural to wonder what kind of effects the preprocessing might have on the modeling procedure. This concern is manifested in the form of recurrent frequently asked questions, such as “how does the preprocessing affect the underlying dynamics?” This paper aims at providing answers to important questions related to (i) data interpolation, (ii) data smoothing, (iii) data-estimated derivatives, (iv) model structure selection, and (v) model validation. The answers provided will hopefully remove some of those doubts and one shall be more confident not only on global modeling but also on various data analyses which may be also dependent on data preprocessing.
Vertically aligned Si intrananowire p-n diodes by large-area epitaxial growth
Authors: Kim Cheol-Joo , Lee Donghun , Lee Hyun-Seung , Lee Geunhee , Kim Gil-Sung , Jo Moon-Ho
Published: April 2009

We demonstrate fabrication of vertically aligned, intrananowire p-n diodes by large-area epitaxial growth of Si nanowires (NWs). The axially modulated doping profile of p-n junctions is achieved by in situ doping with alternating addition of dopants in the axial sequence during Au-assisted chemical vapor deposition. We provide direct evidence of the intra-NW p-n junctions using scanning local probes in both individual NWs and vertically aligned NWs at large areas. Our study suggests implication for integrated electronics and optoelectronics based on bottom-up Si NWs.
“Torsional tapping” atomic force microscopy using T-shaped cantilevers
Authors: Mullin Nic , Vasilev Cvetelin , Tucker Jaimey D. , Hunter C. Neil , Weber Christa H. M. , Hobbs Jamie K.
Published: April 2009

Torsional oscillation of atomic force microscope cantilevers has been shown to offer increased optical lever sensitivity, quality factor, resonant frequency, and stiffness as compared to flexural oscillation. In this letter, T-shaped cantilevers are oscillated torsionally to give a tapping motion at the tip. This gives many of the advantages of small cantilevers, without the requirement for specialized detection optics. In order to demonstrate the capability of this technique, high resolution images of LH2 membrane protein crystal structures are presented. Reduced settle time and tip-sample force under error signal are also demonstrated.
High coupling piezoelectric thin films of Pb(Zr,Ti)O3-based ternary perovskite compounds for GHz-range film bulk acoustic resonators
Authors: Yamauchi N. , Shirai T. , Yoshihara T. , Hayasaki Y. , Ueda T. , Matsushima T. , Wasa K. , Kanno I. , Kotera H.
Published: April 2009

We have deposited nearly stress-free single-crystal thin films of (001) Pb(Mn,Nb)O3–Pb(Zr,Ti)O3 (PMnN-PZT) on (001)MgO substrates by rf-magnetron sputtering using a quenching process after the film growth. It is found that single c-domain/single-crystal thin films of PMnN-PZT containing 5%–10% PMnN show a strong hard ferroelectric response with 2Ec≅400 kV/cm and Ps≅70 μC/cm2. GHz-range film bulk acoustic resonators incorporating PMnN-PZT thin films have been fabricated with microelectromechanical system technology. The maximum electromechanical coupling coefficient kt and mechanical quality factor Qm were 0.7 and 185 in the 4 GHz range, respectively.
Graphene nanoribbon as a negative differential resistance device
Authors: Ren Hao , Li Qun-Xiang , Luo Yi , Yang Jinlong
Published: April 2009

We present a theoretical study on electronic structure and elastic transport properties of armchair graphene nanoribbon based junctions by using density functional theory calculations and nonequilibrium Green’s function technique. The I-V characteristics of various junctions are examined, which all exhibit robust negative differential resistance (NDR) phenomena. It is found that such NDR behaviors originate from the interaction between the narrow density of states of the doped leads and the discrete states in the scattering region.
Electrostrain-controlled displacement-permeability in composite of ferroelectrics and heterotypic complex ferrite
Authors: Wang Z. L. , Luo X. B. , Zhang N. , Fang X. , Mao J. M.
Published: April 2009

By using the product effects of electrostrain and displacement-permeability, a composite containing a bar of Pb(Zr,Ti)O3 and two I-shaped ferrites were developed, and its electromagnetic effect was investigated. Under a constant electric field of 5 kV/cm, about 36% of the electric field-controlled permeability and impedance were observed in a considerably wide scope of frequency. The electric-field dependent inductance and impedance of the composite device showed a ferroelectric relaxation behavior. Analysis showed that the degenerating field-dependent permeability was responsible for the electromagnetic effects observed.
An Agent-Based Model of Residential Choice Dynamics in Nonstationary Housing Markets
Authors: Devisch Oswald T J , Timmermans Harry J P , Arentze Theo A , Borger Aloys W J
Published: April 2009

This paper presents an agent-based model developed to simulate residential choice behaviour in a nonstationary housing market. The model is built around the assumption that agents have incomplete and imperfect knowledge, and thus have to base their decisions on beliefs. The aim is to illustrate how the agents deal with the uncertainty inherent in these beliefs, both at the level of a single agent, deciding among a set of successive actions, and at the level of a group of agents, negotiating over the price of a house.
Individuals' Activity–Travel Rescheduling Behaviour: Experiment and Model-Based Analysis
Authors: Nijland E W Linda , Arentze Theo A , Borgers Aloys W J , Timmermans Harry J P
Published: April 2009

Rescheduling of daily activities and associated travel in response to unforeseen events such as travel delays is receiving increased attention in the context of traffic management. In this paper we describe the results of a stated adaptation experiment held among a large sample of individuals through a web-based questionnaire, to estimate parameters of such dynamic behaviour. In the experiment subjects indicated their response to a reduction in available time for a planned activity in a number of hypothetical situations. A mixed logit model was used to estimate subjective preferences for adapting in certain ways conditional upon activity attributes and socioeconomic variables. The results indicate that location and transport-mode adaptations are rare compared with duration adjustment or postponing (or cancelling) the activity dependent on the relative size of reduced time. Socioeconomic variables and activity attributes also play a significant role.
Controllable Synthesis of Pyrazolo[3,4-b]pyridines or Substituted Malononitrile Derivatives through Multi-Component Reactions in Ionic Liquid
Authors: Zhang Xinying , Li Xiaoyan , Fan Xuesen , Wang Xia , Wang Jianji , Qu Guirong
Published: April 2009

A multi-component reaction of aldehyde, malononitrile, and 5-amino-3-methyl-1-phenylpyrazole was carried out smoothly in [bmim][BF4] without any added catalyst. Through this reaction, pyrazolo[3,4-b]pyridines or substituted malononitrile derivatives were obtained conveniently and controllably at different temperatures. The ionic liquid used can be easily recovered and efficiently reused for at least five runs.
Graphisins A and B from the Lichen Graphis tetralocularis
Authors: Pittayakhajonwut Pattama , Sri-indrasutdhi Veera , Dramae Aibrohim , Lapanun Sanisa , Suvannakad Rapheephat , Tantichareon Morakot
Published: April 2009

Crude extracts of the lichen Graphis tetralocularis exhibited antimycobacterial activity, with minimum inhibitory concentration (MIC) values in a range of 100–200 μg mL–1. Chemical investigation of the broth led to the isolation of acremonidin E (1) and graphisins A (2) and B (3). Acremonidin E (1) displayed antitubercular activity with MIC values of 50 μg mL–1 and showed cytotoxicity against BC, KB, and NCI-H187 cell lines with IC50 values of 12.79–27.12 μg mL–1, whereas graphisins A (2) and B (3) were inactive to these tests.
SiO2·12WO3·24H2O: a Highly Efficient Catalyst for the Synthesis of 5-Arylidene Barbituric Acid in the Presence of Water
Authors: Li Ji-Tai , Sun Ming-Xuan
Published: April 2009

The condensation of aromatic aldehydes and barbituric acid catalyzed by SiO2·12WO3·24H2O in aqueous media at room temperature gave 5-arylidene barbituric acid in high yields with or without the use of ultrasound, providing a simple and efficient route to synthesis of these compounds.
Facile Synthesis of 4,5-Dihydro-1,3,4-Thiadiazoles by 1,3-Dipolar Cycloaddition of Thioisomünchnones
Authors: Sánchez Bárbara , Bravo José Luis , Arívalo María Josí , López Ignacio , Light Mark E. , Silvero Guadalupe
Published: April 2009

The present paper summarizes a straightforward synthesis of 4,5-dihydro-1,3,4-thiadiazoles by the 1,3-dipolar cycloaddition of thioisomünchnones. These reactions have been carried out in dichloromethane and are essentially complete within 60 min at room temperature. Under such mild conditions the asymmetric version has been explored as well. Unequivocal structure elucidation has been accomplished by means of one- and two-dimensional NMR techniques as well as X-ray structure analysis.
The 'Refoldability' of Selected Proteins in Ionic Liquids as a Stabilization Criterion, Leading to a Conjecture on Biogenesis
Authors: Byrne Nolene , Belieres Jean-Philippe , Angell C. Austen
Published: April 2009

The folding of proteins is usually studied in dilute aqueous solutions of controlled pH, but it has recently been demonstrated that reversible unfolding can occur in other media. Particular stability is conferred on the protein (folded or unfolded) when the process occurs in ‘protic ionic liquids’ (pILs) of controlled proton activity. This activity (‘effective pH’) is determined by the acid and base components of the pIL and is characterized in the present study by the proton chemical shift of the N–H proton. Here we propose a ‘refoldability’ or ‘refolding index’ (RFI) metric for assessing the stability of folded biomolecules in different solvent media, and demarcate high RFI zones in hydrated pIL media using ribonuclease A and hen egg white lysozyme as examples. Then we show that, unexpectedly, the same high RFIs can be obtained in pIL media that are 90% inorganic in character (simple ammonium salts). This leads us to a conjecture related to the objections that have been raised to ‘primordial soup’ theories for biogenesis, objections that are based on the observation that all the bonds involved in biomacromolecule formation are hydrolyzed in ordinary aqueous solutions unless specifically protected. The ingredients for primitive ionic liquids (NH3, CO, HCN, CO2, and water) were abundant in the early earth atmosphere, and many experiments have shown how amino acids could form from them also. Cyclical concentration in evaporating inland seas could easily produce the type of ambient-temperature, non-hydrolyzing, media that we have demonstrated here may be hospitable to biomolecules, and that may be actually encouraging of biopolymer assembly. Thus a plausible variant of the conventional ‘primordial soup’ model of biogenesis is suggested.
Structural Characterization of Novel Ionic Salts Incorporating Trihalide Anions
Authors: Dean Pamela M. , Clare Bronya R. , Armel Vanessa , Pringle Jennifer M. , Forsyth Craig M. , Forsyth Maria , MacFarlane Douglas R.
Published: April 2009

The crystal structures of several low-melting salts containing trihalide ions, namely 1-ethyl-3-methylimidazolium tribromide ([C2mim][Br3]), 1-ethyl-1-methylpyrrolidinium tribromide ([C2mpyr][Br3]), and 1-propyl-1-methylpyrrolidinium triiodide ([C3mpyr][I3]), are reported for the first time. Thermal analysis reveals that the tribromide salts are lower-melting than their monohalide analogues. Analysis of the crystal structures allows examination of the influence of the anions on the physical properties of the salts.
Metal-TUD-1 Catalyzed Aerobic Oxidation of Cyclohexane: A Comparative Study
Authors: Anand Ramanathan , Hamdy Mohamed S. , Parton Rudy , Maschmeyer Thomas , Jansen Jacobus C. , Gläser Roger , Kapteijn Freek , Hanefeld Ulf
Published: April 2009

The relative performance of various metal-incorporated mesoporous silicas of the TUD-1 structure type (M-TUD-1, where M = Ti, Cr, Co, Fe, Cu, Mn) in the selective aerobic oxidation of cyclohexane with tert-butylhydroperoxide and cyclohexylhydroperoxide (CHHP) to the respective hydroperoxides and subsequent decomposition to the alcohol and ketone is reported. In particular, relationships regarding metal type and loading, silica structure type and peroxide initiator are elucidated, to show that it is possible to tune catalysts for either CHHP formation or CHHP decomposition.
Corrigendum to: Microwave-Assisted Tandem Processes for the Synthesis of N-Heterocycles
Authors: Abid Mohammed , Török Béla , Huang Xudong
Published: April 2009

Over the years, microwave-assisted organic synthesis (MAOS) became a commonly applied mainstream tool for the synthesis of heterocyclic compounds. The broad range of emerging applications in this field is mainly due to the significant contribution of MAOS to the development of ecofriendly processes. Various transformations have been developed for the synthesis of N-heterocycles under microwave conditions, including fast and selective processes. Tandem reactions involving greener reaction media, solvent-free conditions, and solid-phase synthesis are of exceptional interest in this area. In most transformations, microwave conditions dramatically enhanced reaction rates, as well as provided improved yields. This account highlights the most recent advancements in MAOS-based tandem processes for the synthesis of N-heterocycles.
Processing of Electric Arc Furnace Dust using Deep Eutectic Solvents
Authors: Abbott Andrew P. , Collins John , Dalrymple Ian , Harris Robert C. , Mistry Reena , Qiu Fulian , Scheirer James , Wise William R.
Published: April 2009

The present paper describes the design and operation of the first large-scale extraction and separation of metals from a complex matrix using an ionic liquid. The liquid was a deep eutectic solvent based on choline chloride. The hydrogen-bond donors were mixed to optimize solubility and fluid viscosity. It was found that the incorporation of a fine particulate dust actually decreased the viscosity of the fluid. The present paper shows that selective extraction of zinc and lead can be achieved through judicious choice of the hydrogen-bond donor and it is also shown that metals in solution can be separated using cementation with zinc powder. Electrowinning of pure zinc is demonstrated but scale-up tests suggest that the process is relatively slow and has poor current efficiency. An alternative methodology was developed to rapidly recover the zinc from solution using dilute ammonia solution. It is also shown for the first time that cementation can be efficiently carried out in ionic liquids because the recovered metal is porous and allows thick layers to be deposited.
A Novel µ1,1-Azido-, µ2-Alkoxo-, and µ2-Phenoxo-Bridged Tetranuclear Copper(II) Complex with a Quinquedentate Schiff-Base Ligand: Magneto-Structural and DFT Studies
Authors: Basak Subhra , Sen Soma , Rosair Georgina , Desplanches Cédric , Garribba Eugenio , Mitra Samiran
Published: April 2009

A novel tetranuclear copper(ii) complex [Cu4L2(μ1,1- N3)2]·CH3CN (1) has been synthesized using a symmetrical quinquedentate N2O3-donor Schiff-base ligand H3L (N,N′-(2-hydroxypropane-1,3-diyl)bis(2- hydroxyacetophenimine)) and characterized by elemental analysis, Fourier-transform (FT)-IR, UV-visible, electron paramagnetic resonance spectroscopy, and cyclic voltammetry. The X-ray single-crystal structure of 1 reveals three kinds of bridges among the four metal centres: one from the exogenous azido ligand and two from the phenoxo and alkoxo moieties of the Schiff base. The same structure highlights the remarkable versatility of copper(ii) to adopt an array of stereochemistries. Four unusual eight-membered metallacycles exist in 1. The μ1,1-azido, μ2-alkoxo, and μ2-phenoxo bridges among the four copper centres have facilitated interesting magnetic interactions that have been elucidated by variable-temperature magnetic susceptibility measurements and backed up by density functional theory calculations. Detailed analyses have shown that the antiferromagnetic effect through the alkoxo-bridged CuII centres combined with the ferromagnetic interaction through the azido-bridged metal centres results in an S = 0 ground state.
Prediction of the Standard Enthalpy of Formation of Pure Compounds Using Molecular Structure
Authors: Gharagheizi Farhad
Published: April 2009

A predictive approach has been presented to calculate the standard enthalpy of formation of pure compounds based on a quantitative structure–property relationship technique. A large number (1692) of pure compounds were used in this study. A genetic algorithm based on multivariate linear regression was used to subset variable selection. Using the selected molecular descriptors an optimized feed forward neural network was presented to predict the ΔHfo of pure compounds.
An Efficient and Simple One-Pot Synthesis of ?-Acetamido Ketones Catalyzed by Ytterbium Triflate in Ionic Liquid
Authors: Kumar Anil , Rao M. Sudershan , Ahmad Israr , Khungar Bharti
Published: April 2009

Ytterbium triflate immobilized in the ionic liquid [bmim][BF4] catalyzes the three-component coupling of aromatic aldehydes, enolizable ketones, and acetonitrile in the presence of acetyl chloride at room temperature to afford β-acetamido ketones in good yields. The catalyst can be recovered and recycled for subsequent reactions without any appreciable loss of efficiency.
Phosphonium-Based Ionic Liquids: An Overview
Authors: Fraser Kevin J. , MacFarlane Douglas R.
Published: April 2009

Phosphonium cation-based ionic liquids (ILs) are a readily available family of ILs that in some applications offer superior properties as compared to nitrogen cation-based ILs. Applications recently investigated include their use as extraction solvents, chemical synthesis solvents, electrolytes in batteries and super-capacitors, and in corrosion protection. At the same time the range of cation–anion combinations available commercially has also been increasing in recent years. Here, we provide an overview of the properties of these interesting materials and the applications in which they are appearing.
Why are Ionic Liquids Attractive for CO2 Absorption? An Overview
Authors: Huang Junhua , Rüther Thomas
Published: April 2009

As the climate debate is hotting up, so is the (re)search for finding powerful new materials for the efficient and cost-effective removal of CO2 from flue-gas streams from power plants and other emission sources. Ionic liquids (ILs), exhibiting higher CO2 solubility than conventional organic solvents, have received considerable interest as new CO2 absorbents. The present paper evaluates the advantages and disadvantages of ILs, and provides an overview of the recent developments of ILs for CO2 capture. In conventional ILs, CO2 is absorbed by occupying the free space between the ions through physical absorption mechanisms. As another promising strategy, task-specific ILs have been studied that, by attaching functional groups to the ions, allow the formation of chemical bonds to improve the overall absorption capacity during the CO2 capture process. Other strategies include using ILs as reaction media or as selective absorption materials.
PEDOT-Coated Counter Electrodes for Dye-Sensitized Solar Cells
Authors: Pringle Jennifer M. , Armel Vanessa , Forsyth Maria , MacFarlane Douglas R.
Published: April 2009

Poly(3,4-ethylenedioxythiophene) (PEDOT)-coated counter electrodes for dye-sensitized solar cells have been prepared at ambient temperature and without the use of iron-based oxidants, using an ionic liquid for the synthesis of the PEDOT. These electrodes show comparable electrocatalytic performance with conventional Pt-coated counter electrodes (solar cell efficiencies >7.5%).
Correlations in the Structure and Dynamics of Ionic Liquids
Authors: Gray-Weale Angus
Published: April 2009

A very great deal of the experimental work on room-temperature ionic liquids was done after high-performance computing became readily available for quantum-chemical or molecular-dynamic calculations. I explore the use of modern computational methods to guide or aid laboratory work, and the importance of ‘old-fashioned’ theory, from before the age of fast computers. Debye and Hückel published the first really important theoretical work on correlations between charged particles, and the Nernst–Einstein formula is still used to understand electrical conductivities. I assess the usefulness of all these theoretical methods and ideas, and discuss the particular difficulties presented by ionic liquids.
Effects of radio-tagging on two-year-old, endangered Macquarie perch (Macquaria australasica: Percichthyidae)
Authors: Broadhurst Ben T. , Ebner Brendan C. , Clear Rhian C.
Published: April 2009

Radio-telemetry provides an effective means of studying the habitat use of threatened fishes where repeated recapture of individuals is undesirable. In these circumstances, it is especially important to ensure that radio-tagging methods are appropriate for the particular species of interest. An aquaria-based evaluation of three methods for radio-tagging two-year-old Macquaria australasica was conducted until 28 days post-surgery. Successful radio-tagging was determined from three indicators: (1) survival; (2) healing of the surgical incision or tag attachment site; and (3) resumption of feeding. Internal-coil radio-tags proved to be the most suitable radio-tag type, with complete survivorship and tag retention for the duration of the trial and fish commonly resuming normal feeding behaviour within two days post-surgery. In contrast, implanting a radio-tag internally and exiting a whip antenna is unsuitable for M. australasica on the basis of poor survivorship, rejection of radio-tags, and prolonged alteration of feeding behaviour. No mortality or radio-tag rejection was observed in association with externally attached whip-antenna radio-tags, and post-surgery resumption of feeding was comparable with that of fish with internal-coil radio-tags. However, external radio-tags caused substantial abrasion of the epidermis and loss of scales. Internal-coil tags should be applied in radio-tracking studies of this species.
Use of satellite telemetry on small-bodied waterfowl in Australia
Authors: Roshier David A. , Asmus Martin W.
Published: April 2009

The nomadic or dispersive movements of many Australian waterfowl in response to irregular environmental cues make satellite telemetry studies the only means by which these long-distance movements can be tracked in real time. Unlike some large-bodied soaring species, attaching satellite transmitters to small-bodied waterfowl (<1 kg) is not straightforward because ducks have high wing loadings and need to maintain active flapping to stay aloft. In the present paper, we detail one harness design and attachment method that enabled us to track grey teal (Anas gracilis) for up to 879 days. In addition, we detail rates of data loss, changes in data quality over time and variation in data quality from solar-powered satellite-tags deployed on ducks in Australia and Papua New Guinea. Up to 68% of all locational fixes have a nominal accuracy of less than 1 km, and satellite-tags deployed on wild birds can provide up to 22 location fixes per day and store enough energy during the day to run continuously throughout the night.
Remote monitoring of crocodilians: implantation, attachment and release methods for transmitters and data-loggers
Authors: Franklin Craig E. , Read Mark A. , Kraft Peter G. , Liebsch Niko , Irwin Steve R. , Campbell Hamish A.
Published: April 2009

Crocodilians are by their very nature difficult animals to study. However, research on wild animals is essential for the development of reliable long-term management. Here, we describe methods for the acquisition and monitoring of behavioural and physiological variables from free-ranging crocodilians through the use of archival tags (data-loggers) and via satellite, radio and acoustic telemetry. Specifically, the attachment or implantation of electronic tags is described and examples provided of the type of data that can be collected. Our research group has used a combination of approaches to monitor the movements, diving activity, body temperatures and heart rates of crocodilians, including studies on the Australian freshwater crocodile (Crocodylus johnstoni), the estuarine crocodile (Crocodylus porosus) and the caiman (Caiman latirostris). Each approach or method presents unique challenges and problems, chiefly as a consequence of differences in body morphology and size of the crocodilian species, their behaviours and the habitats they occupy.
Telemetry tagging methods for some freshwater reptiles
Authors: Doody J. Sean , Roe John , Mayes Phillip , Ishiyama Lesley
Published: April 2009

Reptiles are often ignored or under-studied in freshwater systems. An understanding of their biology and thus their role in aquatic communities can be greatly advanced by studies using radio telemetry. In turn, the value of radio telemetry for research depends on the availability of suitable and reliable methods of attaching or implanting radio transmitters. The present study describes transmitter attachment and implantation techniques for selected freshwater reptiles, including the eastern and northern long-necked turtles (Chelodina longicollis and Chelodina rugosa, respectively), the pig-nosed turtle (Carettochelys insculpta), Mertens’ water monitor (Varanus mertensi) and the water dragon (Physignathus lesueurii). The effectiveness of the methods for each species is described and the potential pitfalls and challenges of each method are discussed. The literature abounds with techniques for attachment and implantation techniques, and the methods used in the present study are not wholly novel. The aim, however, is to provide detailed summaries, in one paper, of effective methods for attachment and implantation of radio-tags for freshwater reptiles with a diversity of sizes, shapes and attachment surfaces. Despite the focus on Australian freshwater reptiles, these methods are applicable to aquatic reptiles worldwide.
Radio-tagging and tracking of translocated trout cod (Maccullochella macquariensis: Percichthyidae) in an upland river
Authors: Ebner B. C. , Johnston L. , Lintermans M.
Published: April 2009

Radio-tracking provides an effective means of studying the spatial ecology of threatened fishes where almost inaccessible habitats and species rarity render conventional mark–recapture methods impractical. Initially, validation of an effective radio-tagging method is required; in the present study, an aquaria trial based on nine hatchery-reared, adult male Maccullochella maquariensis (Percichthyidae) was conducted. Fish resumed feeding within days of being internally implanted with a radio-tag, and tag rejection was not observed (0%, n = 9) based on a 2-month observational period. Following release into an upland stream, individual-specific movements resulted in upstream (n = 1) and downstream (n = 6) dispersal as well as fidelity to the release site (n = 2) at the completion of the study. Individuals established small home-ranges (mean length of river used by an individual per diel period ranged from 47 to 292 m) and were most active in the early morning and evening (n = 6). Complete survivorship of individuals bearing active radio-transmitters (n = 8) was recorded up until 4 months after release. However, an estimated zero or one individual was alive when the last active radio-tag expired 11 months after release (n = 8). The present study highlights the use of radio-tracking in monitoring the dispersal and survivorship of small numbers of hatchery-reared threatened fish released into natural habitats as part of species re-introduction programs.
Gender-bending aubergines: molecular phylogenetics of cryptically dioecious Solanum in Australia
Authors: Martine Christopher T. , Anderson Gregory J. , Les Donald H.
Published: April 2009

The causes, consequences and correlates of dioecy have been the subject of much discussion since the days of Darwin. Several recent authors have stressed the importance of informing this body of theory, with studies focusing on lineages in which both dioecy and hermaphroditism are present. The genus Solanum is an ideal group for analysis, because dioecy, hermaphroditism and potential unisexual transitions (e.g. andromonoecy) among them all occur. Phylogenetic hypotheses are presented for the Australian species in Solanum subgenus Leptostemonum (the ‘spiny solanums’) section Melongena, which contains 10 of the 14 currently described dioecious species in the genus. Phylogenetic analysis of the ITS and trnK–matK gene regions supports a single origin of dioecy from andromonoecy in Australian Solanum. The causes, mechanisms, and maintenance of dioecy in Australian Solanum are explored, including the role of past climate change in the establishment of centres of endemism.
A revision of Westringia section Cephalowestringia (Lamiaceae: Westringieae)
Authors: Guerin G. R.
Published: April 2009

The Western Australian endemic Westringia section Cephalowestringia Kuntze includes all species of Westringia Sm. (Lamiaceae: subfamily Prostantheroideae: tribe Westringieae) with pseudo-capitate inflorescences. Westringia subgenus Muellera B.Boivin is treated as a synonym of the section. The first taxonomic revision of the section is presented on the basis of morphological and morphometric analyses and recognises five taxa, including the following three new taxa described here: W. acifolia G.R.Guerin, W. capitonia G.R.Guerin and W. cephalantha var. caterva G.R.Guerin.
Filter feeders and plankton increase particle encounter rates through flow regime control
Authors: Humphries Stuart
Published: April 2009

Collisions between particles or between particles and other objects are fundamental to many processes that we take for granted. They drive the functioning of aquatic ecosystems, the onset of rain and snow precipitation, and the manufacture of pharmaceuticals, powders and crystals. Here, I show that the traditional assumption that viscosity dominates these situations leads to consistent and large-scale underestimation of encounter rates between particles and of deposition rates on surfaces. Numerical simulations reveal that the encounter rate is Reynolds number dependent and that encounter efficiencies are consistent with the sparse experimental data. This extension of aerosol theory has great implications for understanding of selection pressure on the physiology and ecology of organisms, for example filter feeders able to gather food at rates up to 5 times higher than expected. I provide evidence that filter feeders have been strongly selected to take advantage of this flow regime and show that both the predicted peak concentration and the steady-state concentrations of plankton during blooms are ≈33% of that predicted by the current models of particle encounter. Many ecological and industrial processes may be operating at substantially greater rates than currently assumed.