Coulometric-potentiometric determination of the autoprotolysis constant and the relative acidity scale of water

The autoprotolysis constant and the relative acidity scale of water were determined by applying the coulometric-potentiometric method and a hydrogen/palladium (H2/Pd) generator anode. In the described procedure for the evaluation of the autoprotolysis constant, a strong base, coulometrically generated in situ at the platinum cathode in the electrolytic cell, in the presence of sodium perchlorate as the supporting electrolyte, was titrated with hydrogen ions obtained by the anodic oxidation of hydrogen dissolved in the palladium electrode. The titration was performed with a glass-SCE electrode pair at 25.0±0.1 °C. The obtained value, pK w = 13.91±0.06, is in agreement with literature data. The range of the acidity scale of water was determined from the difference between the half-neutralization potentials of the electrogenerated perchloric acid and that of sodium hydroxide in a sodium perchlorate medium. The half-neutralization potentials were measured using both a glass-SCE and a (H2/Pd) ind-SCE electrode pair. A wider range of the relative acidity scale of water was obtained with the glass-SCE electrode pair. 2010 Copyright (CC) SCS

Quantum Hypothesis Testing and Non-Equilibrium Statistical Mechanics

We extend the mathematical theory of quantum hypothesis testing to the general $W^*$-algebraic setting and explore its relation with recent developments in non-equilibrium quantum statistical mechanics. In particular, we relate the large deviation principle for the full counting statistics of entropy flow to quantum hypothesis testing of the arrow of time.Comment: 60 page

Modeling and Simulation of a TFET-Based Label-Free Biosensor with Enhanced Sensitivity

This study discusses the use of a triple material gate (TMG) junctionless tunnel field-effect transistor (JLTFET) as a biosensor to identify different protein molecules. Among the plethora of existing types of biosensors, FET/TFET-based devices are fully compatible with conventional integrated circuits. JLTFETs are preferred over TFETs and JLFETs because of their ease of fabrication and superior biosensing performance. Biomolecules are trapped by cavities etched across the gates. An analytical mathematical model of a TMG asymmetrical hetero-dielectric JLTFET biosensor is derived here for the first time. The TCAD simulator is used to examine the performance of a dielectrically modulated label-free biosensor. The voltage and current sensitivity of the device and the effects of the cavity size, bioanalyte electric charge, fill factor, and location on the performance of the biosensor are also investigated. The relative current sensitivity of the biosensor is found to be about 1013. Besides showing an enhanced sensitivity compared with other FET- and TFET-based biosensors, the device proves itself convenient for low-power applications, thus opening up numerous directions for future research and applications

The application of hydrogen-palladium electrode for potentiometric acid-base determinations in tetrahydrofuran

The application of the hydrogen-palladium electrode (H2/Pd) as an indicator electrode for the determination of the relative acidity scale (Es, mV) of tetrahydrofuran (THF) and potentiometric titrations of acids in this solvent were investigated. The relative acidity scale of THF was determined from the difference between the half-neutralization potentials of perchloric acid and tetrabutylammonium hydroxide (TBAH), which were measured using both H2/Pd-SCE and glass-SCE electrode pairs. The experimentally obtained value of the Es scale of THF with the H2/Pd-SCE electrode pair was 1155 mV, while that obtained with the glass-SCE electrode pair was 880 mV. By using an H2/Pd indicator electrode, the individual acids (benzoic acid, palmitic acid, maleic acid, acetyl acetone and α-naphthol) and two component acid mixtures (benzoic acid + α-naphthol, palmitic acid + α-naphthol, maleic acid + α-naphthol and maleic acid + phthalic acid) were titrated with a standard solution of TBAH. In addition, sodium methylate and potassium hydroxide proved to be very suitable titrating agents for the titrations of the individual acids and the acids in mixtures, respectively. The relative error of the determination of acids in the mixtures was less than 3 %. The results are in agreement with those obtained using a conventional glass electrode. The advantages of the H2/Pd electrode over a glass electrode in the potentiometric acid-base determinations in THF lie in the following: this electrode gives a wider relative acidity scale for THF, larger potential jumps at the titration end-point and relatively fast response times. Furthermore, it is very durable, simple to prepare and can be used in the titrations of small volumes. © 2013 (CC) SCS

Entropic Fluctuations in Statistical Mechanics I. Classical Dynamical Systems

Within the abstract framework of dynamical system theory we describe a general approach to the Transient (or Evans-Searles) and Steady State (or Gallavotti-Cohen) Fluctuation Theorems of non-equilibrium statistical mechanics. Our main objective is to display the minimal, model independent mathematical structure at work behind fluctuation theorems. Besides its conceptual simplicity, another advantage of our approach is its natural extension to quantum statistical mechanics which will be presented in a companion paper. We shall discuss several examples including thermostated systems, open Hamiltonian systems, chaotic homeomorphisms of compact metric spaces and Anosov diffeomorphisms.Comment: 72 pages, revised version 12/10/2010, to be published in Nonlinearit

The Diffusion of the Magnetization Profile in the XX-model

By the $C^*$-algebraic method, we investigate the magnetization profile in the intermediate time of diffusion. We observe a transition from monotone profile to non-monotone profile. This transition is purely thermal.Comment: Accepted for publication in Phys. Rev.

Fluctuations of Quantum Currents and Unravelings of Master Equations

The very notion of a current fluctuation is problematic in the quantum context. We study that problem in the context of nonequilibrium statistical mechanics, both in a microscopic setup and in a Markovian model. Our answer is based on a rigorous result that relates the weak coupling limit of fluctuations of reservoir observables under a global unitary evolution with the statistics of the so-called quantum trajectories. These quantum trajectories are frequently considered in the context of quantum optics, but they remain useful for more general nonequilibrium systems. In contrast with the approaches found in the literature, we do not assume that the system is continuously monitored. Instead, our starting point is a relatively realistic unitary dynamics of the full system.Comment: 18 pages, v1-->v2, Replaced the former Appendix B by a (thematically) different one. Mainly changes in the introductory Section 2+ added reference

Second order perturbation theory for embedded eigenvalues

We study second order perturbation theory for embedded eigenvalues of an abstract class of self-adjoint operators. Using an extension of the Mourre theory, under assumptions on the regularity of bound states with respect to a conjugate operator, we prove upper semicontinuity of the point spectrum and establish the Fermi Golden Rule criterion. Our results apply to massless Pauli-Fierz Hamiltonians for arbitrary coupling.Comment: 30 pages, 2 figure

Nonequilibrium Steady States and Fano-Kondo Resonances in an AB Ring with a Quantum Dot

Electron transport through a strongly correlated quantum dot (QD) embedded in an Aharonov-Bohm (AB) ring is investigated with the aid of the finite-U slave-boson mean-field (SBMF) approach extended to nonequilibrium regime. A nonequilibrium steady state (NESS) of the mean-field Hamiltonian is constructed with the aid of the C*-algebraic approach for studying infinitely extended systems. In the linear response regime, the Fano-Kondo resonances and AB oscillations of the conductance obtained from the SBMF approach are in good agreement with those from the numerical renormalization group technique (NRG) by Hofstetter et al. by using twice larger Coulomb interaction. At zero temperature and finite bias voltage, the resonance peaks of the differential conductance tend to split into two. At low bias voltage, the split of the asymmetric resonance can be observed as an increase of the conductance plateau. We also found that the differential conductance has zero-bias maximum or minimum depending on the background transmission via direct tunneling between the electrodes.Comment: 24 pages,17 figure

Hydrogel application in cabbage production

Na zemljištu tipa černozem, na melioracionom sistemu na Rimskim šančevima, ispitivan je različit način primene hidrogela na prinos i komponente prinosa u proizvodnji ranog kupusa. U ogledu su bile zastupljene četiri varijante: kontrola - bez primene hidrogela, gel - nabubreli hidrogel unešen u sadne jamice, prah - suvi hidrogel u prahu unešen u sadne jamice, prah - suvi hidrogel u prahu rasturen po površini zemljišta u obliku traka i inkorporiran. U zavisnosti od godine ispitivanja, primena hidrogela ispoljila je različite uticaje i na prinos i morfološke karakteristike ranog kupusa. Suma padavina u periodu vegetacije imala je najveći uticaj.Different methods of hydrogel application were tested for effects on early cabbage grown on irrigated chernozem soil in Rimski šančevi location. The study included four variants: control without hydrogel application, gel - watered hydrogel granules placed into planting holes, granules - dry hydrogel granules placed into planting holes, granules - dry hydrogel granules applied in bands on soil surface and incorporated. Different weather conditions affected the impact of hydrogel application on the yield and morphological characteristics of early cabbage in the different test years. Precipitation sum during growing season exhibited the highest impact on the studied parameters