On oxidative degradation of parchment and its non-destructive characterisation and dating

Historic parchment is an extremely complex material, not only due to the various methods of production used and various past environmental histories of objects, but also due to its inhomogeneous structure. Many traditional methods of characterisation are empirical, but useful since they have gained recognition by the end-users. In this paper, we investigated the shrinkage temperature of collagen and the influence of lipids contained in parchment on the measurements. While the content of lipids does not seem to significantly affect shrinkage temperature measurements themselves, it strongly affects the decrease of shrinkage temperature of collagen during degradation, and thus its thermomechanical properties. This confirms the high importance of lipid peroxidation during degradation of parchment.     

X-ray emission via Kα resonance complexes in gold ions

The excitation energies from ground state for 63 fine structure levels of the terms belonging to 1 s², 1snl, 2lnl′ (n = 2,3), 3l3l′ (l ≠ ≠ l′) configurations of Au⁷⁷⁺, as well as oscillator strengths for electric-dipole-allowed and intercombination transitions among the fine-structure levels were theoretically evaluated. The important relativistic effects in intermediate coupling are incorporated by means of the Breit–Pauli Hamiltonian. Extensive comparisons are performed with several approximations and previous data sets in order to size up contributing effects and to estimate accuracy ratings. The atomic excitation is obtained by electron impact in close coupling approach. For optically allowed transitions, the electron-impact collision strengths at collision energy up to 80 keV are reported. The results are relevant to the laboratory and astrophysical plasmas.     

Thermal analysis of binary liquid crystals eutectic system cholesteril p-phenoxi phenyl carbamate–cholesteril p-biphenyl carbamate

For a binary mixture of two liquid crystals, cholesteril p-phenoxi phenyl carbamate and cholesteril p-biphenyl carbamate, the solidus?Cliquidus equilibrium was investigated using differential scanning calorimetry (DSC) and the thermodynamic parameters were obtained. Simple eutectic point was observed for this system, situated approximately at the same temperature for all the studied compositions. This behavior is favored by grinding and is more evident in the composition 50:50. The excess functions G ^E and S ^E for the pre-, post-, and eutectic composition have been calculated using the phase diagram data. Comparing the experimental data with the existing theoretical data, the system deviation from the ideal behavior is observed. The structure of pure compounds was elucidated using FT-IR and hot-stage polarizing microscopy.     

Thermal behavior of aminotrimethoxysilanphosphonate functionalized onto styrene-divinylbenzene copolymer

Abstract

The chlorometylated styrene–divinylbenzene copolymer with different percent of divinylbenzene (code: S-6.7 DVB, S-12DVB, and S-15DVB) was functionalized with 3-hydroxybenzaldehyde for obtaining intermediated polymers. The aminotrimethoxysilanphosphonate groups were grafted by one-pot reactions in tetrahydrofuran using three components: polymers grafted with aldehyde groups (code: CHO-6.7, CHO-12, and CHO-15), 3-aminopropyltrimethoxysilane, diethylphosphite. The aminotrimethoxysilanphosphonate groups functionalized onto styrene-(6.7, 12, and 15%) divinylbenzene copolymer (code: PAF-6.7, PAF-12, and PAF-15) and evolution of the reaction were evidenced by FT-IR spectroscopy and porous structure by N₂ adsorption-desorption, SEM microscopy. The thermal behavior of aldehydes and materials: PAF-6.7, PAF-12, and PAF-15 are different than initial polymer supports.     

Kinetics of tartrazine photodegradation by UV/H2O2 in aqueous solution

In the present work, kinetics of tartrazine decay by UV irradiation and H₂O₂ photolysis, and the removal of total organic carbon (TOC) under specific experimental conditions was explored. Irradiation experiments were carried out using a photoreactor of original design with a low-pressure Hg vapour lamp. The photodegradation rate of tartrazine was optimised with respect to the H₂O₂ concentration and temperature for the constant dye concentration of 1.035 × 10^?5 M. Tartrazine degradation and the removal of TOC followed the pseudo-first-order kinetics. The much higher k _obs value for tartrazine degradation (7.91 × 10^?4 s^?1) as compared with the TOC removal (2.3 × 10^?4 s^?1) confirmed the presence of reaction intermediates in the solution.     

Thermal behaviour and spectroscopic studies of complexes of some divalent transitional metals with 2-benzoil-pyridil-izonicotinoylhydrazone

New complexes of 2-benzoyl-pyridil-isonicotinoylhydrazone (L) with Cu(II), Co(II), Ni(II) and Mn(II), having formula of type [ML₂] SO₄·xH₂O (M = Cu²⁺, Co²⁺, Ni²⁺, x = 2 and M = Mn²⁺, x = 3), have been synthesised and characterised. All complexes were characterised on the basis of elemental analyses, IR spectroscopy, UV–VIS–NIR, EPR, as well as thermal analysis and determination of molar conductivity and magnetic moments. The thermal behaviour of complexes was studied using thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The structure of L hydrazone was established by X-ray study on single crystal. The ligand works as tridentate NNO, being coordinated through the azomethine nitrogen, the pyridine nitrogen and carbonylic oxygen. Heats of decomposition, ΔH, associated with the exothermal effects were also determined.     

Optimal control for infinite dimensional stochastic differential equations with infinite Markov jumps and multiplicative noise

In this paper we solve an infinite-horizon linear quadratic control problem for a class of differential equations with countably infinite Markov jumps and multiplicative noise. The global solvability of the associated differential Riccati-type equations is studied under detectability hypotheses. A nonstochastic, operatorial approach is used. Some properties of the linear stochastic systems, such as stability, stabilizability and detectability, are also discussed on the basis of a new solution representation result. A generalized Ito's formula which applies to infinite dimensional stochastic differential equations with countably infinite Markov jumps is also provided.     

Analytic inner shell internal conversion coefficients for screened Coulomb potentials

An analytic method is presented for evalution of internal conversion coefficients (ICC) in inner shells of neutral or ionized atoms. Analytic formulas for ICC are given which include electron screening and static nuclear size effects. Predictions have also been obtained from these formulas for point Coulomb ICC or for screening effects included only in bound state normalization. Very good agreement with full numerical calculations is found, except in those cases where the formation region of the ICC is not well inside the atom. While the discussion in this paper concerns mediumZ elements (30<Z<80) and not too low energy, the method can be extended to other situations. The method is suited also for ICC of the inner shells of ionized atoms, even for very high degree of ionization.