A study for the selection of NPE-free cocktails for LSC routine measurements

Journal of Radioanalytical and Nuclear Chemistry - In this paper a study for the selection of an NPE (nonylphenol ethoxylates)—free cocktail is discussed in order to be used for our routine...     

Redox-Mediated Alcohol Oxidation Coupled to Hydrogen Gas Formation in a Dye-Sensitized Photosynthesis Cell

This work reports a dye-sensitized photoelectrochemical cell (DSPEC) that couples redox-mediated light-driven oxidative organic transformations to reductive hydrogen (H₂) formation. The DSPEC photoanode consists of a mesoporous anatase TiO₂ film on FTO (fluorine-doped tin oxide), sensitized with the thienopyrroledione-based dye AP11 , while H₂ was formed at a FTO-Pt cathode. Irradiation of the dye-sensitized photoanode transforms 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) to the oxidized TEMPO (TEMPO⁺), which acts as a chemical oxidant for the conversion of benzyl alcohol. The TEMPO^0/+ couple, previously used as redox mediator in DSSC, mediates efficient electron transfer from the organic substrate to the photo-oxidized dye. A DSPEC photoreactor was designed that allows in situ monitoring the reaction progress by infrared spectroscopy and gas chromatography. Sustained light-driven oxidation of benzyl alcohol to benzaldehyde within the DSPEC photoreactor, using of TEMPO as mediator, demonstrated the efficiency of the device, with a photocurrent of 0.4 mA cm⁻², approaching quantitative Faradaic efficiency and exhibiting excellent device stability.     

Eigenfunctions of transfer operators and cohomology

The eigenfunctions with eigenvalues 1 or −1 of the transfer operator of Mayer are in bijective correspondence with the eigenfunctions with eigenvalue 1 of a transfer operator connected to the nearest integer continued fraction algorithm. This is shown by relating these eigenspaces of these operators to cohomology groups for the modular group with coefficients in certain principal series representations.     

The Fundamental Equations of Change in Statistical Ensembles and Biological Populations

A recent article in Nature Physics unified key results from thermodynamics, statistics, and information theory. The unification arose from a general equation for the rate of change in the information content of a system. The general equation describes the change in the moments of an observable quantity over a probability distribution. One term in the equation describes the change in the probability distribution. The other term describes the change in the observable values for a given state. We show the equivalence of this general equation for moment dynamics with the widely known Price equation from evolutionary theory, named after George Price. We introduce the Price equation from its biological roots, review a mathematically abstract form of the equation, and discuss the potential for this equation to unify diverse mathematical theories from different disciplines. The new work in Nature Physics and many applications in biology show that this equation also provides the basis for deriving many novel theoretical results within each discipline.     

Neutron spectrum calibration using the Cd-ratio for multi-monitor method with a synthetic multi-element standard

Several methods are in use for the determination of the thermal to epithermal neutron fluence rate ratio (f) and the deviation of the epithermal neutron spectrum from the 1/E shape parameter (α). In our former work, it was proven that the recently developed and characterized Synthetic Multi-ELement Standard (SMELS) can be used for the fast verification of the stability of the irradiation parameters using the Au-Zr bare monitor method. However, this latter method using SMELS had a too low precision for an accurate determination of f and α. Therefore, the Cd-ratio for multi-monitor method using SMELS was investigated for two irradiation channels. As shown the material can also be used as a monitor for the calibration of an irradiation facility.     

Trace element determination in beauty products by k0-instrumental neutron activation analysis

A recent study on trace elements in beauty products and cosmetics sold on the Asian market has shown the presence of high levels of U, Th and rare earth elements in so called “Hormesis cosmetics.” For the purpose of comparison, some more information about trace elements in European cosmetics would be useful. In this paper the results obtained using k ₀-standardised Instrumental Neutron Activation Analysis (k ₀-INAA) for more than 20 trace elements in 20 different beauty products collected from the European market are presented. We found traces of Ba, As and Sb which is in breach with European legislation. For some of the other elements like Cr and Co further speciation is needed in order to evaluate their presence in beauty products.     

Near-Integrability and Recurrence in FPU Chains with Alternating Masses

Journal of Nonlinear Science - An important aspect of understanding FPU chains is the existence of invariant manifolds (called “bushes”) in FPU chains. We will focus on the classical...     

Sums of Kloosterman sums for real quadratic number fields

We estimate sums of Kloosterman sums for a real quadratic number field F of the type