Binary nucleation in acid–water systems. I. Methanesulfonic acid–water

Experimental measurements of binary nucleation between methanesulfonic acid and water vapor were carried out for relative acidities (Ra), 0.05<Ra<0.65, and relative humidities (Rh), 0.06<Rh<0.65, using a continuous flow mixing-type device. The number concentration of particles leaving the nucleation and growth tube was measured as a function of the initial relative humidity and the relative acidity in the temperature range from 20 to 30 °C. Particle size distributions were also measured and found to vary with the amount of water and acid present. The system was simulated to predict the total number of particles and the total mass of acid in the aerosol phase using a simple integral model and classical binary nucleation theory allowing for the formation of acid–water hydrates in the gas phase. At low particle concentrations, condensation rates did not significantly change the saturation levels and the nucleation rates were estimated from the total number concentration data as functions of Ra, Rh, and temperature. The values of experimental and theoretical nucleation rates differed significantly, with Jexpt/Jtheor changing as a function of temperature from 10^–8 to 10^–4 as temperature varied from 20 to 30 °C. This work represents the first systematic experimental study of the temperature dependence of binary nucleation

Binary nucleation in acid–water systems. II. Sulfuric acid–water and a comparison with methanesulfonic acid–water

This work presents a systematic investigation of binary nucleation rates for sulfuric acid and water and the effect of temperature on these rates at isothermal, subsaturated conditions. The results from nucleation rate measurements for the sulfuric acid (H2SO4)–water system are discussed and compared to those previously presented for methanesulfonic acid (MSA)–water [B. E. Wyslouzil, J. H. Seinfeld, R. C. Flagan, and K. Okuyama, J. Chem. Phys. (submitted)]. Experiments were conducted at relative humidities (Rh) ranging from 0.006<Rh<0.65, relative acidities (Ra) in the range of 0.04<Ra<0.46, and at three temperatures, T=20, 25, and 30 °C, in the continuous flow mixing-type apparatus described in Paper I. Particles were formed by binary nucleation and grew by condensation as the mixed stream flowed through an isothermal glass tube. Number concentrations observed at the exit of the nucleation and growth tube as a function of Rh and Ra are extremely sensitive to the binary nucleation rate, and from these data the nucleation rate was estimated as a function of saturation level and temperature. Particle size distributions were also measured using a specially constructed differential mobility analyzer. As anticipated, the H2SO4 particles formed by nucleation and growth are much smaller than those formed in the MSA–water experiments, but particle size distribution measurements confirm that most of the particles formed are being observed. The ratio of experimental to theoretical nucleation rates, Jexpt/Jtheor, was found to be a strong function of the predicted number of acid molecules in the critical nucleus for both the H2SO4–water and MSA–water systems

Enhanced quasiparticle heat conduction of the multigap superconductor Lu2Fe3Si5

The thermal transport measurements have been made on the Fe-based superconductor Lu2Fe3Si5 (Tc ~ 6 K) down to a very low temperature Tc/120. The field and temperature dependences of the thermal conductivity confirm the multigap superconductivity with fully opened gaps on the whole Fermi surfaces. In comparison to MgB2 as a typical example of the multigap superconductor in a p-electron system, Lu2Fe3Si5 reveals a remarkably enhanced quasiparticle heat conduction in the mixed state. The results can be interpreted as a consequence of the electronic correlations derived from Fe 3d-electrons.Comment: 5 pages, 4 figure

Disorder-sensitive superconductivity in the iron silicide Lu2_2Fe3_3Si5_5 studied by the Lu-site substitutions

We studied effect of non-magnetic and magnetic impurities on superconductivity in Lu$_2$Fe$_3$Si$_5$ by small amount substitution of the Lu site, which investigated structural, magnetic, and electrical properties of non-magnetic (Lu$_{1-x}$Sc$_x$)$_2$Fe$_3$Si$_5$, (Lu$_{1-x}$Y$_x$)$_2$Fe$_3$Si$_5$, and magnetic (Lu$_{1-x}$Dy$_x$)$_2$Fe$_3$Si$_5$. The rapid depression of $T_c$ by non-magnetic impurities in accordance with the increase of residual resistivity reveals the strong pair breaking dominated by disorder. We provide compelling evidence for the sign reversal of the superconducting order parameter in Lu$_2$Fe$_3$Si$_5$.Comment: 4 pages, 5 figure

Pre-Harvest Sprouting Tolerance in 36 Bread Wheat Genotypes

Pre-harvest sprouting (PHS), promoted by rainfall during crop maturity, is a high problem in many wheat-producing regions of the world. Considering its importance in Brazil, 36 national and international varieties and advanced lines of wheat were evaluated for their tolerance to PHS. For this purpose, two experiments were conducted over three years. Seed pericarp rupture was used as an indicator of the beginning of germination. The data were analyzed using analysis of variance, the Scott-Knott test, and the Lin and Binns method. The wide range of germination percentage values allowed the genotypes to be classified as tolerant (in experiment 1 - ND 674 and Grandin*2/RL 4137 and experiment 2 - Frontana and Grandin) and moderately tolerant (Alsen, CD 114, and Milan/3/Attila//Fang 69/CIMMYT 3 in Experiment 1; Avante, BRS 177, IAC 5-Maringá, Onix, OR 1, RL 4137, and Rubi in Experiment 2). Because tolerance to PHS is under genetic control and can be improved through breeding programs, the challenge for wheat breeders is to combine increased PHS tolerance with other requirements to meet market demands

Correlation Functions of Complex Matrix Models

For a restricted class of potentials (harmonic+Gaussian potentials), we express the resolvent integral for the correlation functions of simple traces of powers of complex matrices of size $N$, in term of a determinant; this determinant is function of four kernels constructed from the orthogonal polynomials corresponding to the potential and from their Cauchy transform. The correlation functions are a sum of expressions attached to a set of fully packed oriented loops configurations; for rotational invariant systems, explicit expressions can be written for each configuration and more specifically for the Gaussian potential, we obtain the large $N$ expansion ('t Hooft expansion) and the so-called BMN limit.Comment: latex BMN.tex, 7 files, 6 figures, 30 pages (v2 for spelling mistake and added reference) [http://www-spht.cea.fr/articles/T05/174

Studies in binary nucleation: The dibutylphthalate/dioctylphthalate system

A continuous-flow mixing apparatus has been developed for the study of binary nucleation. This apparatus has been used to investigate the nucleation of mixed dibutylphthalate/dioctylphthalate vapors, and the interaction of the two vapors in particle formation has been demonstrated. A model that considers competition between nucleation and condensation processes during particle formation is applied in the analysis of the experimental results, allowing comparison of the magnitudes of the theoretical and actual nucleation rates in both the single-component and mixed vapor systems

Tachyon Kink on non-BPS Dp-brane in the General Background

This paper is devoted to the study of the tachyon kink on the worldvolume of a non-BPS Dp-brane that is embedded in general background, including NS-NS two form B and also general Ramond-Ramond field. We will explicitly show that the dynamics of the kink is described by the equations of motion that arrise from the DBI and WZ action for D(p-1)-brane.Comment: 28 page

D1-brane with Overcritical Electric Field in AdS3 and S-brane

We study aspects of Dirichlet S-branes, which are defined as Dirichlet boundary condition on a time like embedding of open strings, in general backgrounds. By applying T-duality along an isometry of the unphysical dS2-branes in NS-NS supported AdS3-background, we find S0-brane. We also study the time dependent tachyon condensation on the unstable Dp-brane and interpret the singular solutions as lower dimensional S(p-1)-brane that couples to real Ramond-Ramond fields while to imaginary NS-NS modes.Comment: 23 pages, JHEP style, V2: minor changes, typos fixe

Witten's Vertex Made Simple

The infinite matrices in Witten's vertex are easy to diagonalize. It just requires some SL(2,R) lore plus a Watson-Sommerfeld transformation. We calculate the eigenvalues of all Neumann matrices for all scale dimensions s, both for matter and ghosts, including fractional s which we use to regulate the difficult s=0 limit. We find that s=1 eigenfunctions just acquire a p term, and x gets replaced by the midpoint position.Comment: 24 pages, 2 figures, RevTeX style, typos correcte