Chemometrics for Data Interpretation: Application of Principal Components Analysis (PCA) to Multivariate Spectroscopic Measurements

Extracting relevant and useful information from measurements is an issue of paramount importance and it can be considered as complementary to the process of data acquisition. This is a crucial point especially in the field of chemical measurements, where data sets can consist of hundreds or even thousands of variables so their interpretation can require long time. Chemometrics try to tackle this issue by applying mathematical and statistical tools to data coming from chemical, biological or medical analyses. Among possible methods, Principal Components Analysis (PCA) has found wide application in the I-M field thanks to its ability to identify patterns in acquired measurements and classify data in different groups. Possible applications span from chemicals detection [1] to concentration estimation of compounds in a given system [2]. Actually, many studies demonstrated the possibility to use PCA to process different kinds of data [3], in some cases coupling PCA to other tools such as artificial neural networks to improve the processing performance [4]

Measurement techniques for microbial corrosion assessment

L'abstract è presente nell'allegato / the abstract is in the attachmen

Editorial to selected papers from the IMEKO TC24 Special Issue "Measurements in Cultural Heritage"

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Suidae Transition at the Miocene-Pliocene Boundary : a Reassessment of the Taxonomy and Chronology of Propotamochoerus provincialis

The Miocene-Pliocene (Turolian-Ruscinian) transition represents a fundamental interval in the evolution of Euro-Mediterranean paleocommunities. In fact, the paleoenvironmental changes connected with the end of the Messinian salinity crisis are reflected by a major renewal in mammal faunal assemblages. An important bioevent among terrestrial large mammals is the dispersal of the genus Sus, which replaced all other suid species during the Pliocene. Despite its possible paleoecological and biochronological relevance, correlations based on this bioevent are undermined by the supposed persistence of the late surviving late Miocene Propotamochoerus provincialis. However, a recent revision of the type material of this species revealed an admixture with remains of Sus strozzii, an early Pleistocene (Middle Villafranchian to Epivillafranchian) suid, questioning both the diagnosis and chronological range of P. provincialis. Here we review the late Miocene Suidae sample recovered from the Casino Basin (Tuscany, central Italy), whose taxonomic attribution has been controversial over the nearly 150 years since its discovery. Following a comparison with other Miocene, Pliocene, and Pleistocene Eurasian species, the Casino Suidae are assigned to P. provincialis and the species diagnosis is emended. Moreover, it is recognized that all the late Miocene (Turolian) European Propotamochoerus material belongs to P. provincialis and that there is no compelling evidence of the occurrence of this species beyond the Turolian-Ruscinian transition (MN13-MN14)

A fuzzy data meta training system for ranking hub container terminals

The potential and critical aspects of any transport service can be highlighted through the estimation of appropriate performance indicators of the examined system. Commonly, container terminal analysis is based first on the evaluation and comparison of quantitative parameters that describe the level of service of the terminal and, on the other side by means of performance indicators related to terminal productivity. In this paper a Fuzzy Inference System for evaluation of a synthetic performance indicator is proposed. This tool could help planners and managers in terminals performances analysis and ranking as well as in assessing the effects of possible intervention on the systems. The proposed approach is suitable in the case of hub container ports. In fact this system is characterised by significant uncertainties and it is not always governed by certain rules, rational behaviour, so that it cannot be easily represented by traditional mathematical techniques and models. In our opinion, could be convenient to define the values of the considered parameters by explicitly define them in an approximate way, that is to say by fuzzy sets

Study of Methanol Concentration Effect in Direct Methanol Fuel Cells by Electrochemical Impedance Spectroscopy

This paper analyzes and discusses the performance of a DMFC as a function of methanol aqueous solution concentration fed at the anode, using the Electrochemical Impedance Spectroscopy (EIS). Impedance data obtained were analyzed through the development of an equivalent circuit model. Electrochemical impedance spectroscopy was used to estimate the membrane conductivity and to model the electrochemical behavior of electrodic reactions inside the fuel cell, revealing a worse overall performance by increasing methanol concentration at the anode

Cloud based sensor network for environmental monitoring

This paper describes a complete infrastructure for environmental monitoring, which is based on a cloud architecture. The proposed system employs small button-like battery-operated sensors, which connect through a wireless link to small receivers capable of routing data to the cloud system. Cloud data can be accessed in real time through smart-phones and downloaded for further analyses. Each button-like sensor is capable of measuring temperature and humidity for more than one year without attendance. All data are sent to the receiver and in addition stored inside the button memory so that the system can work also in the absence of power and Internet connection. The architecture takes advantage of the μPanel environment, which is conceived to work also with unreliable and slow Internet connections and permits to implement a cloud-based infrastructure with the capability to control the sensors locally and in absence of Internet connectivity. The proposed architecture is currently used in different museums to monitor the local environment inside the display rooms, but the system can be easily extended to open environments without additional costs

Effect of TiO2 and Al2O3 Addition on the Performance of Chitosan/Phosphotungstic Composite Membranes for Direct Methanol Fuel Cells

: Composite chitosan/phosphotungstic acid (CS/PTA) with the addition of TiO2 and Al2O3 particles were synthesized to be used as proton exchange membranes in direct methanol fuel cells (DMFCs). The influence of fillers was assessed through X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, liquid uptake, ion exchange capacity and methanol permeability measurements. The addition of TiO2 particles into proton exchange membranes led to an increase in crystallinity and a decrease in liquid uptake and methanol permeability with respect to pristine CS/PTA membranes, whilst the effect of the introduction of Al2O3 particles on the characteristics of membranes is almost the opposite. Membranes were successfully tested as proton conductors in a single module DMFC of 1 cm2 as active area, operating at 50 °C fed with 2 M methanol aqueous solution at the anode and oxygen at the cathode. Highest performance was reached by using a membrane with TiO2 (5 wt.%) particles, i.e., a power density of 40 mW cm-2, almost doubling the performance reached by using pristine CS/PTA membrane (i.e., 24 mW cm-2)

Electrochemical measurements and microscopy on hybrid coatings for metallic artefacts

Electrochemical Impedance Spectroscopy and Scanning ElectroChemical Microscopy are employed to characterize innovative hybrid coatings, which can be proposed for the corrosion protection of cultural metallic artefacts. In this paper hybrid TEOS and Graphene Oxide epoxy coatings have been tested in view of their possible employment as protective coatings for archaeological iron artefacts. The coatings have been deposited on low carbon steel and exposed to aggressive solutions. The performance of EIS and ElectroChemical Microscopy have been compared with the final aim of investigating if the proposed measuring approaches can easily give useful results to help the restorers in the choice of the conservation methodology. Comparing results from the two techniques can give a deeper knowledge of the coating performance and of their degradation mechanism