Shaft design: A semi-analytical finite element approach

This work deals with the practical use of semi-analytical finite elements in the machine design. The case of mechanical shafts is considered. The most usual loading condition characterized by the presence of axial, torsional, bending, and shear loads can be modeled by over imposing an axi-symmetric, an axi-antisymmetric and a harmonic load, corresponding to the first three terms of the Fourier series expansion, if semi-analytical plane finite element is used. A practical case is presented and the advantages, with respect to the three-dimensional approach in terms of computational time and accuracy for stress and displacement evaluation, is put in evidence.     

Macrocycles for the complexation of radiocesium: a concise review of crystallographic and computational studies

Journal of Radioanalytical and Nuclear Chemistry - We review the crystallographic studies concerned with the complexes between cesium and different types of macrocycles. A detailed examination of...     

Isotope dilution method for the assay of rotenone in olive oil and river waters by liquid chromatography/multiple reaction monitoring tandem mass spectrometry

A new approach for the assay of rotenone (1) by isotope dilution mass spectrometry is presented. The extreme toxicity of rotenone, a natural phytodrug with insecticidal and piscicidal activity, recently banned by national and international environmental protection agencies, calls for the development of sensitive and accurate methods of analyses. Accordingly, the proposed protocol is based on the availability of the labeled internal standard rotenone‐d₃ (3) which can be conveniently prepared by consecutive and specific mono‐O‐demethylation, and remethylation with methyl iodide‐d₃. The sensitivity of the method is confirmed by the very low limit of detection (LOD) and quantitation (LOQ) values achieved in the assay of 1 in two distinct fortified matrices, and is further supported by the observed accuracy values. Copyright © 2009 John Wiley & Sons, Ltd.     

1H NMR metabolite fingerprinting as a new tool for body fluid identification in forensic science

In this feasibility study, we propose, for the first time, ¹H NMR spectroscopy coupled with mathematical strategies as a valid tool for body fluid (BF) trace identification in forensic science. In order to assess the ability of this approach to identify traces composed either by a single or by two different BFs, samples of blood, urine, saliva, and semen were collected from different donors, and binary mixtures were prepared. ¹H NMR analyses were carried out for all samples. Spectral data of the whole set were firstly submitted to unsupervised principal component analysis (PCA); it showed that samples of the same BF cluster well on the basis of their characterizing molecular components and that mixtures exhibit intermediate characteristics among BF typologies. Furthermore, samples were divided into a training set and a test set. An average NMR spectral profile for each typology of BF was obtained from the training set and validated as representative of each BF class. Finally, a fitting procedure, based on a system of linear equations with the four obtained average spectral profiles, was applied to the test set and the mixture samples; it showed that BFs can be unambiguously identified, even as components of a mixture. The successful use of this mathematical procedure has the advantage, in forensics, of overcoming bias due to the analyst's personal judgment. We therefore propose this combined approach as a valid, fast, and non‐destructive tool for addressing the challenges in the identification of composite traces in forensics. Copyright © 2013 John Wiley & Sons, Ltd.     

Moment based approaches to value the risk of contingent claim portfolios

In this paper we describe and apply the estimating function methodology to value the risk of asset derivative portfolios. We first implement the Li’s model based on the first four moments and then we show the limits of this model in forecasting the maximum loss of contingent claims. In addition, we show that four moments are not enough to describe the behavior of the lower percentiles of derivatives. Finally, we propose a model that considers the first six moments and we compare the performances of these models proposing a backtest analysis on several historical and truncated asset derivative portfolios.