Analytical Instrumental Techniques to Study Archaeological Wood Degradation

Abstract

Historically, a very large variety of everyday artifacts were made of wood, which makes them representative of their historical period or social context and valuable for archaeologists and historians. In order to preserve degraded wood and to develop and apply suitable conservation treatments, chemical and physical characterization of archaeological wood is needed. This review provides the reader with a survey on state-of-the-art of instrumental analytical tools available to understand the morphology and the chemical composition of archaeological wood. The focus is on microscopic and spectroscopic techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman, nuclear magnetic resonance (NMR) and analytical techniques based on pyrolysis, such as direct exposure–mass spectrometry (DE-MS), pyrolysis–mass spectrometry (Py-MS), pyrolysis–gas chromtography–mass spectrometry (Py-GC/MS), with emphasis on their respective potentialities and limitations. The advantages of techniques based on synchrotron radiation are also discussed. In addition, the applicability of each examined technique is illustrated and discussed through specific examples from the literature.     

On a one-dimensional version of the dynamical Marguerre-Vlasov system

A one-dimensional version of the so-called Marguerre-Vlasov system of equations describing the vibrations of shallow shells is considered. The system depends on a parameter 0 in a singular way and undergoes the effect of damping mechanisms. We show that the system converges to a nonlinear beam equation while the energy decays exponentially uniformly (on 0) as time goes to infinity.     

A note on the Union-Intersection character of some MANOVA procedures

A decomposition termed the matrix-decomposition of the MANOVA hypothesis is discussed. On the basis of this decomposition the Hotelling-Lawley trace statistic is derived as a Union-Intersection (U-I) statistic. A new derivation of the c₁-statistic is obtained as a particular case of the U-I nature of all the procedures in a class specified by Definition 3.4.     

On the inverse problem for three-dimensional potential scattering

We consider a linear perturbation for the wave equation $\text{□u = 0}\text{in}\text{Ω = E}{}^3$ by “repulsive” smooth potentials q(y) that are small at infinity and suitably small (in magnitude). We use a time-dependent approach to prove that the scattering operator S(q) determines uniquenes uniquely the scatterer q (at least in this class). Energy inequalities will play a central role in our discussion.     

Dendrimer-tetrachloroplatinate precursor interactions. 1. Hydration of Pt(II) species and PAMAM outer pockets

Density functional theory is used to investigate the structure and energetics of the tetrachloroplatinate anion and its hydrolysis products at several degrees of hydration, as well as those of outer dendrimer pockets hosting such species. The number of water molecules able to saturate an unprotonated outer dendrimer pocket is found to be two, as inferred from calculated thermodynamic data. However, such a number could not be established for a protonated pocket where the dendrimer adopts a more open configuration. An analysis of possible pocket configurations is done on the basis of the orientations of the amide O atoms in the outer pockets. The effect of explicit water on the infrared spectra of the dendrimer pockets is reported and compared to experimental values.     

Chemoenzymatic total synthesis of cryptocaryalactone natural products

A new chemoenzymatic route for the preparation of cryptocaryalactones natural products using a kinetic resolution process as the key step is described. Novozyme-435 catalyzed hydrolysis of the prochiral (±)-monoester 7 afforded the precursors of cryptocaryalactones with high enantiomeric excess and excellent yields. The compounds (4S,6S)-7 and (4R,6R)-7 were converted to (+)-(6R,2′S)-cryptocaryalactone (1) and (?)-(6S,2′R)-cryptocaryalactone (2), respectively by employing Wittig-olefination, lactonization and acylation reactions.     

Ion motion and charge transfer through a solid-electrolyte interphase: an atomistic view

Journal of Solid State Electrochemistry - Solid-electrolyte interphase (SEI) films forming at the surface of anode electrodes are known as one of the crucial aspects that decide battery performance...