Stiffening effect of bolt-on transducers on strain measurements

The strain of a structural element is often measured indirectly by determining the strain of a transducer that is supposed to follow the deformation of the element perfectly, and with negligible interaction, around the mounting point. However, this assumption is not always true, and depends on the stiffness of the transducer relative to the local stiffness of the piece to which it is attached. This paper deals with the problem of evaluating the influence that a relatively rigid transducer (the HBM SLB-700A was chosen as an example) has on the strain field, studied from both the theoretical and the experimental points of view. The findings of the research have shown that, in order to interpret the measurements obtained from this kind of instruments correctly, the perturbation induced on the strain field cannot be disregarded. A corrective factor, obtained numerically by means of the FEM and discussed in the paper, can be used as a first approximation to evaluate the true strain, stress and forces in common structural steel elements

Influence of chemical and mineralogical soil properties on the adsorption of sulfamethoxazole and diclofenac in Mediterranean soils

Abstract Background The irrigation with treated wastewaters can be a way for the introduction of organic contaminants in soils. However, their adsorption onto soils can allow a control of their bioavailability and leaching. The adsorption is influenced by properties of contaminants (water solubility, chemical structure) and soils (organic matter content, pH, mineralogy). This study aimed to investigate the effect of mineralogical composition, organic matter content and others parameters of soils on the adsorption of sulfamethoxazole (SMX) and diclofenac (DCF), two contaminants of emerging concerns (CECs), in real cases (Altamura, Sibari and Noci soils). Results The isotherms data showed that the adsorption of the two CECs closely matched the Freundlich model, even if the DCF could also fit the linear one. The only exception was the adsorption of SMX on the soil of Sibari, for which Langmuir's model fitted better. In all cases, the Kd values were the highest for Altamura soil according mainly to its content of organic carbon. Positive correlations were found between Kd value of DCF and the soil organic carbon and Al oxyhydroxides content, suggesting their roles in its adsorption, while SMX showed only a slight positive correlation with the soil organic carbon content. Finally, between the two CECs studied, DCF was more adsorbed than SMX also because of the lower water solubility of the former. Conclusions The good interaction between DCF and soil organic carbon suggests the organic amendment of soils before the application of treated watewaters. The low adsorption of SMX onto soils suggests greater leaching of this compound which is, therefore, potentially more dangerous than DCF. For this reason, the application of a filtration system with appropriate adsorbent materials before the application of wastewater to soils should be expected. Graphical Abstrac

Petroarcheometric Analysis on Obsidian Artefacts Found Within Some Neolithic – Eneolithic Period Caves of Southern Italy

AbstractIn the last twenty years, obsidian artefacts have been found in important and often extensive karst cavities in Southern Italy: three located in Calabria (Grotta della Monaca, and Grotta del Tesauro, in Sant'Agata di Esaro, Cosenza; Grotta Pietra Sant'Angelo in San Lorenzo Bellizzi, Cosenza), one in Puglia (Grotta di Santa Barbara in Polignano a Mare, Bari) and another in Campania (Grotta di Polla, Salerno). All these sites, that have returned a total of 151 obsidian tools, were connected to human frequentation of the underground environments that occurred during the Holocene, which can be precisely located in the vast period between the Neolithic and the Eneolithic (6th–4th millennium BC). They are mainly blades and bladelets, but also burins together with scrapers and cores, generally of small dimensions. SEM-EDS and WD-XRF absolutely non-destructive analyses carried out on these items have shown that all samples have a source area in the obsidian outcrops of the island of Lipari (Messina, Italy). These data confirm that the Aeolian island of Lipari furnished the privileged obsidian extraction outcrops for most of the Neolithic and Eneolithic archaeological sites of Southern Italy

Reassessment of WD-XRF method for obsidian provenance shareable databases

The X-ray fluorescence technique using peak intensity ratios of trace elements is one of the faster, less expensive and less invasive methods for obsidian sourcing. Moreover, XRF peak intensity ratios are particularly useful when the artifact is slightly altered, particularly affecting the alkali cations, or when its surfaces are covered with a fine film of carbonate deposits formed while the sample was buried. The limitation of this technique results from the dimensions of the obsidian samples: very small obsidian samples, nowadays about 1 cm in size, are difficult to measure given the very few X-rays emitted by their surface. An aluminium holder closed with a very thin Mylar© polyester film was prepared and the specimen, positioned at the centre of the surface of the Mylar film, was placed in the XRF spectrometer. The use of recent technology XRF apparatus equipped with a 4 kW Rh anode X-ray tube coupled with an accurate measurement of refined X-ray characteristic lines, that exclude the X-ray background contribution, of five trace elements (Rb, Sr, Y, Zr, Nb), made it possible to determine the source geological outcrop of archaeological obsidian samples as little as 7 mm and as light as 40 mg. A database of peak intensity ratios, background and interference free, of five trace elements was produced for obsidian samples from Monte Arci, Palmarola, Lipari, Pantelleria, Gyali and Melos. This database may be used by other laboratories provided the X-ray intensity of the trace elements Rb, Sr, Y, Zr, Nb are measured as net intensities, that is purified from the contribution of the background and from interelemental interferences. A comparison between data obtained with two spectrometers, of different generation and differently calibrated, confirmed the possibility of obtaining a database that can be shared with other laboratories. The proposed XRF method was tested on Neolithic obsidians from four Apulian sites (Ripa Tetta at Lucera, Palestra ex G.I.L. at Foggia, Pulo di Molfetta and Grotta di Santa Barbara at Polignano a Mare), whose source outcrops had been also determined by SEM-EDS

La provenienza dell’ossidiana nel Neolitico della Puglia

Il contribuito analizza la provenienza dell’ossidiana nei siti del Neolitico pugliese, dalle fasi antiche alle recenti. Il sistematico programma di determinazioni di provenienza, condotto con metodiche non distruttive, ha messo, infatti, in luce un quadro piuttosto articolato delle diverse fonti di approvvigionamento. Da una parte è stata confermata la netta, talvolta esclusiva, predominanza dell’ossidiana di Lipari durante tutte le fasi del Neolitico, da quelle più antiche a quelle finali; dall’altra sono state evidenziate sia una significativa presenza, più ampia di quanto precedentemente noto, di ossidiana pontina a Monte Aquilone, Passo di Corvo, Masseria Candelaro e a Balsignano, sia l’attestazione, pur estremamente limitata, di ossidiana da Monte Arci all’interno della dolina del Pulo di Molfetta, fonte finora mai documentata né in Italia meridionale né lungo la costa adriatica. Il quadro tracciato permette di formulare alcune ipotesi sul o sui modelli di circolazione di questa materia prima in un territorio in forte sviluppo durante il Neolitico.This paper synthesizes data on the provenance of obsidian in Neolithic sites in Apulia (southern Italy). A systematic programme for determining provenance, carried out with non-destructive techniques, has provided a well-defined outline of the various sources. This has confirmed the clear, sometimes exclusive, predominance of Lipari obsidian in all Neolithic periods. A significant presence of Pontine obsidian at Monte Aquilone, Passo di Corvo, Masseria Candelaro and at Balsignano was confirmed, which is greater than previously thought; as well as an (albeit limited) presence within the Pulo di Molfetta doline of obsidian from Monte Arci – this source has never before been documented either in southern Italy or along the Adriatic coast. This overview allows some hypotheses to be proposed on the circulation model(s) of this raw material in an area that underwent significant development during the Neolithic