376 research outputs found

    Tele-archaeology

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    Tele-archaeology, in its basic sense, may be defined as the use of telecommunications to provide archaeological information and services. Two different kinds of technology make up most of the tele-archaeology applications in use today. The first is used for transferring information from one location to another. The other is multi-way interactive knowledge distribution. In this paper we examine the possibilities of tele-archaeology, and offer a general framework to implement this technology. The main positive effect of tele-archaeology is the move towards a real “distributed interactive archaeology”, which means that archaeological knowledge building is a collective and dynamic series of tasks and processes. An individual archaeologist cannot fully explain his/her data because the explanatory process needs knowledge as raw material, and this knowledge does not exist in the individual mind of the scientist but in the research community as a global set

    Small scale fracture behaviour of multilayer TiN/CrN systems: Assessment of bilayer thickness effects by means of ex-situ tests on FIB-milled micro-cantilevers

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    TiN/CrN multilayered PVD coatings are known to exhibit outstanding micromechanical properties and wear resistance. On the other hand, information on their small scale fracture behaviour is rather scarce. The present work aims to address it by testing to failure FIB-milled microbeams of multilayer TiN/CrN systems with different bilayer periods (8, 19 and 25 nm). In doing so, these micrometric specimens are first FIB notched, and thus deflected by means of a nanoindentation system. It is found that multilayer architecture translates into a beneficial synergic effect regarding critical load for reaching unstable failure; and thus, on energy absorption at fracture. Such behaviour is associated with small scale crack deflection as main toughening mechanism.Peer ReviewedPostprint (author's final draft

    Two geomagnetic regional models for Albania and south-east Italy from 1990 to 2010 with prediction to 2012 and comparison with IGRF-11

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    Here we present a revised geomagnetic reference model for the region comprising Albanian territory, south-east part of Italian Peninsula and Ionian Sea from 1990 to 2010 with prediction to 2012. This study is based on the datasets of magnetic measurements taken during different campaigns in Albania and Italy in the time of concern, together with a total intensity data set from the Ørsted and CHAMP satellite missions. The model is designed to represent the Cartesian components, X, Y, Z and the total intensity F of the main geomagnetic field (and its secular variation) for the period of interest. To develop the model, we applied a Spherical Cap Harmonic Analysis (SCHA) of the geomagnetic potential over a 16° cap with most of the observations concentrated in the central 4° half-angle. The use of a larger cap than that containing the data was made to reduce the typical problems in SV modelling over small regions. Also a new technique, called ``Radially Simplified Spherical Cap Harmonic Analysis" (RS-SCHA), was developed to improve the model especially in the radial variation of the geomagnetic field components. Both these models provide an optimal representation of the geomagnetic field in the considered region compared with the International Geomagnetic Reference Field model (IGRF-11) and can be used as reference models to reduce magnetic surveys undertaken in the area during the time of validity of the model, or to extrapolate the field till 2012

    Deep seafloor magnetic observations under GEOSTAR project

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    Performing good quality magnetic observations is not an easy task; making them in the extreme marine environment is even much more challenging. The European funded GEOSTAR project succeeded in reaching this difficult goal. After the shallow seawater test experiment performed in the Adriatic sea in 1998, the main aims of the GEOSTAR project were achieved two years later during the six-month deep seafloor mission in the Tyrrhenian sea at around 2 km depth. Details and results about the shallow seawater mission in the Adriatic sea were published in previous articles; this paper is concerned with the deep seafloor mission in the Tyrrhenian sea close to Ustica Island and presents some results related to the geomagnetic recordings

    ITalian Geomagnetic Reference Field (ITGRF): update for 2000 and secular variation model up to 2005 by autoregressive forecasting

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    The updated version of the ITalian Geomagnetic Reference Field (ITGRF) for 2000.0 and its secular variation model up to 2005.0 are presented in this paper. The main field model is based on a simple polynomial approximation in latitude and longitude of the geomagnetic field elements computed from IGRF on a 12° „ 11° grid centred over Italy. The annual means from L'Aquila observatory were used to determine the baseline level, imposing a constant observatory anomaly bias. This procedure gives a set of 6 coefficients every 5 years from 1960 to 2005 for the horizontal H, total field F, vertical Z and declination D elements of the geomagnetic field. The extrapolation of ITGRF to 2005 is based on an autoregressive forecasting of the L'Aquila observatory annual means. Comparison of the field values computed from the model with those recorded at the other Italian observatory (Castello Tesino) shows that the ITGRF improves the fit of the secular variation pattern with respect to the global IGRF model by a factor of 3. The ITGRF represents a reliable alternative to global models when reducing magnetic surveys to a common reference epoch over the Italian region

    A geometric analysis of hallux valgus: correlation with clinical assessment of severity

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    <p>Abstract</p> <p>Background</p> <p>Application of plane geometry to the study of bunion deformity may represent an interesting and novel approach in the research field of hallux valgus. For the purpose of contributing to development of a different perspective in the assessment of hallux valgus, this study was conducted with three objectives: a) to determine the position on the intersection point of the perpendicular bisectors of the longitudinal axes of the first metatarsal and proximal phalanx (IP), b) to correlate the location of this point with hallux valgus deformity according to angular measurements and according to visual assessment of the severity carried out by three independent observers, and c) to assess whether this IP correlated with the radius of the first metatarsophalangeal arc circumference.</p> <p>Methods</p> <p>Measurements evaluated were intermetatarsal angle (IMA), hallux valgus angle (HVA), and proximal phalangeal articular angle (PPAA). The Autocad<sup>Âź </sup>program computed the location of the IP inside or outside of the foot. Three independent observers rated the severity of hallux valgus in photographs using a 100-mm visual analogue scale (VAS).</p> <p>Results</p> <p>Measurements of all angles except PPAA showed significantly lower values when the IP was located out of the foot more distantly and vice versa, significantly higher values for severe deformities in which the IP was found inside the foot (<it>p </it>< 0.001). The IP correlated significantly with VAS scores and with the length of the radius of the circle that included the first metatarsophalangeal arc circumference (<it>p </it>< 0.001)</p> <p>Conclusion</p> <p>The IP is a useful indicator of hallux valgus deformity because correlated significantly with IMA and HVA measurements, VAS scores obtained by visual inspection of the degree of deformity, and location of the center of the first metatarsophalangeal arc circumference.</p

    Two geomagnetic regional models for Albania and south-east Italy from 1990 to 2010 with prediction to 2012 and comparison with IGRF-11

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    Here we present a revised geomagnetic reference model for the region comprising Albanian territory, southeast part of Italian Peninsula and Ionian Sea from 1990 to 2010 with prediction to 2012. This study is based on the datasets of magnetic measurements taken during different campaigns in Albania and Italy in the time of concern, together with a total intensity data set from the ∅rsted and CHAMP satellite missions. The model is designed to represent the Cartesian components, X, Y, Z and the total intensity F of the main geomagnetic field (and its secular variation SV) for the period of interest. To develop the model, we applied a Spherical Cap Harmonic Analysis (SCHA) of the geomagnetic potential over a 16° cap with most of the observations concentrated in the central 4° half-angle. The use of a larger cap than that containing the data was made to reduce the typical problems in SV modelling over small regions. Also a new technique, called "Radially Simplified Spherical Cap Harmonic Analysis" (RS-SCHA), was developed to improve the model especially in the radial variation of the geomagnetic field components. Both these models provide an optimal representation of the geomagnetic field in the considered region compared with the International Geomagnetic Reference Field model (IGRF-11) and can be used as reference models to reduce magnetic surveys undertaken in the area during the time of validity of the model, or to extrapolate the field till 2012

    Tectonic evolution of the Eastern Moroccan Meseta: from Late Devonian fore‐arc sedimentation to Early Carboniferous collision of an Avalonian promontory

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    This study was founded by the Ministerio de Economia y Competitividad (MINECO) of Spain through the project PANGEATOR (CGL2015-71692-P) and the Doctoral scholarship BES-2016-078168. GeoHistory Facility instruments were funded via an Australian Geophysical Observing System grant provided to AuScope Pty Ltd. by the AQ44 Australian Education Investment Fund program. The NPII multicollector was obtained via funding from the Australian Research Council LIEF program (LE150100013). The authors want to express their gratitude to Dr. Manuel Francisco Pereira (University of Evora, Portugal) and Dr. Michel Villeneuve (Centre Europeen de Recherche et d'Enseignement des Geosciences de l'Environnement, France) for their constructive reviews that helped to improve the quality of the original manuscript. Special thanks to Brad McDonald (Curtin University, Australia) for technical assistance regarding LA-ICPMS and Hf analyses, Profs. Abdelfatah Tahiri (University Mohammed V of Rabat, Morocco) and Hassan El Hadi (University Hassan II of Casablanca, Morocco) for their support during field work, Prof. Yvette Kuiper (Colorado School of Mines, USA) for her precious hints about the interpretation of Hf data, and Dr. Lorenzo Valetti for proofreading the manuscript. Supporting information can be obtained in Mendeley Data: https://doi.org/10.17632/b8fdbykmbx.1 (https://data.mendeley.com/datasets/b8fdbykmbx/draft?a=eaae2da0-8e224056-861b-4824984f1c10).The deformed Paleozoic succession of the Eastern Moroccan Meseta crops out in relativelysmall and isolated inliers surrounded by Mesozoic and Cenozoic rocks. Two of the largest inliers(Mekkam and Debdou) are characterized by a monotonous succession of slates and greywackes affected bypolyphasic folding that occurred at low‐to very low grade metamorphic conditions. New U‐Pb ages ondetrital zircon grains from the Debdou‐Mekkam metasediments constrain the maximal depositional age asLate Devonian, interpreted to be close to the true sedimentation age. Furthermore, theΔHfvalues of theDevonian detrital zircons, together with the presence of a series of scattered zircon grains with ages betweenc. 0.9 and c. 1.9 Ga, suggest provenance from a subduction‐related magmatic arc located on the Avalonianmargin. The Debdou‐Mekkam massif is characterized by an Early Carboniferousfirst deformationalevent (D1), which gave way to a pervasive cleavage (S1) associated with plurikilometric‐scale, tight toisoclinal, overturned to recumbent folds. Later events (Dc) occurred at Late Carboniferous time andgenerated variably developed crenulation cleavages (Sc) associated with variously oriented metric‐tokilometric‐scale folds, which complicate the pattern of both D1 intersection lineations (L1) and axial traces.The restoration of this pronounced curved pattern yields originally SW‐NE‐oriented D1 fold axes withregional SE‐vergence. This important Early Carboniferous shortening and SE‐directed tectonic transport canbe explained by closure of the Rheic Ocean and thefirst phases of the collision between the northern passivemargin of Gondwana and an Avalonian promontory.Ministerio de Economia y Competitividad (MINECO) of Spain CGL2015-71692-P BES-2016-078168Australian Geophysical Observing SystemAustralian Education Investment Fund program AQ44Australian Research Council LE15010001
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