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Introduction Educational attainment is associated with important life outcomes including labour market performance, health status, well-being, civic and political participation. An important question is whether it is possible to identify early those students who lack the achievement motivation that is needed to complete a higher education degree. Methods Longitudinal follow-ups of representative samples of participants in the 2000 and 2003 Programme for International Student Assessment (PISA) from Australia, Denmark and Switzerland (N = 3110; 1130; and 1962; age = 15 to 27; % females 51%, 51%, 49%; ethnicity/race unknown) were used to identify the association between a measure of effort on a cognitively demanding low-stake task at age 15 – performance decline during the test – and educational attainment at age 25–27. Results A one SD difference in performance decline was associated with a 5–6 percentage point difference in the probability of obtaining tertiary-level qualifications (r = −0.15 in Australia; −0.11 in Denmark and −0.11 in Switzerland). We find no evidence of differences in this relationship across genders, socio-economic status and baseline levels of ability in the three countries. The association between performance decline and educational attainment is homogeneous across these groups. Self-reported measures of achievement motivation were not predictive of educational attainment in the three countries. Conclusions Our work contributes new longitudinal evidence to the body of research in education employing behavioural measures of motivation and engagement. It can be used to understand the potential long-term consequences of disparities in students' preparation to sustain effort over cognitively demanding tasks.

We investigate whether having an advisor of the same gender is correlated with the productivity of PhD science students and their propensity to stay in academic science. Our analysis is based an original dataset – combined from dissertation abstracts, faculty directories and bibliometric data – covering nearly 20,000 PhD graduates and their advisors from U.S. chemistry departments. We find that students working with advisors of the same gender tend to be more productive during the PhD; and that female students working with female advisors are considerably more likely to become faculty themselves. We suggest that the under-representation of women in science and engineering faculty positions may perpetuate itself through the lower availability of same-gender advisors for female students.

In 2014, an international, interdisciplinary group of experts came together under the auspices of the PISA Governing Board to consider a novel question: can we evaluate, through an international as...

International audience; Reflectance spectroscopy, ultraviolet (UV)fluorescence spectroscopy, and multispectral imaging have been widely employed for pigment identification on paintings. From ancient times to the present, lead white, zinc white, and titanium white have been the most important white pigments used for paintings and they are used as pigment markers for dating a work of art. The spectral behavior of these pigments is reported in several scientific papers and websites, but those of their mixtures are quite unknown. We present a combined nondestructive approach for identifying mixtures of lead white, zinc white, and titanium white as powder and dispersed in two different binder media (egg yolk and linseed oil) by using reflectance spectroscopy, spectrofluorimetry, multispectral reflectance and UV-fluorescence imaging. We propose a novel approach for mapping the presence of white pigments in paintings by false color images obtained from multispectral reflectance and UV-fluorescence images. We found that the presence of lead white mixed with either zinc white or titanium white is highly detectable. Zinc white mixed with lead white or titanium white can be identified due to its UV-fluorescence emission, whereas titanium white in association with lead white or zinc white is distinguishable by its reflectance spectral features. In most cases, the UV-fluorescence analyses also permit the recognition of the binder media in which the pigments are dispersed.

Every three years, the release of the PISA results provides a snapshot of the state of education around the world. For some countries, these results are a wake-up call, challenging policy makers to rethink their strategies and invest more in education. PISA also gives a glimpse into the future by providing reliable measures of the extent to which young adults are ready to participate fully in society. What can the performance of 15-years-old students in 2018 tell us about the world in 2030? Will the high-performing countries have a competitive advantage over the low-performing countries? And does performance in PISA predict the life chances of individual students?

Migration is a shared condition of all humanity. We have all been strangers in a strange land. All humanity lives today as a result of migration, by themselves or their ancestors. Migration is a matter sometimes of choice, often of need, and always an inalienable right. All helpless people deserve to be helped. Offering such help is a commandment and a blessing shared among all religions. Accordingly, as Pope Francis reminds us, our duties to migrants include ‘to welcome’, ‘to protect’, ‘to promote’, and ‘to integrate.’ National borders are not a result of primary natural law, as aren't private property and clothes, ‘because nature did not give [humans] clothes, but art invented them’. National borders depend on social, political and geographical factors. Therefore, faced with current waves of mass migration, in order to establish practices that respond to the common good we need to be guided by three levels of responsibility. The first principle being that ‘in case of need all things are common’, because ‘every man is my brother’. This principle is relative to existence or subsistence and conditions other related issues (such as accommodation, food, housing, security, etc.). Secondly, as part of the fundamental rights of people, legal guarantees of primary rights that foster an ‘organic participation’ in the economic and social life of the nation. Access to these economic and social goods, including education and employment, will allow people to develop their own abilities. Thirdly, a deeper sense of integration, reflecting responsibilities related to protecting, examining and developing the values that underpin the deep, stable, unity of a society- and, more fundamentally, create a horizon of public peace, understood as St. Augustine's ‘tranquility in order’. In particular, with regards to the aforementioned context, policies on migration should be guided by prudence, but prudence must never mean exclusion. On the contrary, governments should evaluate, ‘with wisdom and foresight, the extent to which their country is in a position, without prejudice to the common good of citizens, to offer a decent life to migrants, especially those truly in need of protection. Strangely enough, the response of most governments in the face of this phenomenon only seems to value the third principle, completely disregarding the first two.

This paper reports on a study carried out on patinas covering copper-based Greek and Roman coins found in the archaeological excavation of Regio VIII.7.1-15 in Pompeii (Italy). Since in cultural heritage ancient artefacts should not be damaged, non-destructive and micro-destructive techniques have been used to identify typical and uncommon compounds and to characterize the surface morphology. The chlorine content of light green patinas and the presence of typical minerals allowed us to identify the bronze disease. Coins from the same stratigraphic unit have shown different morphologies of corrosion, probably due to different micro-environmental conditions.

The migration of young Chinese scientists to undertake graduate studies in U.S. universities is arguably one of the most important recent episodes of skilled migration. Using a new data set covering around 16,000 Ph.D. graduates in 161 U.S. chemistry departments, we show that Chinese students have a scientific output during their thesis that is significantly higher than other students. In fact, conditional on acceptance into the same programs, Chinese students perform about as well as the awardees of the NSF doctoral fellowship program. These results shed new light on the benefits of student migration on scientific productivity of destination countries. © 2013 The President and Fellows of Harvard College and the Massachusetts Institute of Technology.

By linking environmental quality to economic growth, green growth is emerging as a new paradigm for urban policies. The paper discusses a policy package for green growth of cities and regional economies, made of four interlocking pillars: a) greener public services and purchasing behavior, b) eco-efficiency of industrial production, c) consumer awareness and demand incentives, d) support for research and innovative applications of green technologies. Urban green growth strategies are more likely to succeed if they account for policy interventions in each of these four domains. Prioritization among the different interventions needs to be based on an accurate screening of possible complementarities among the four pillars. Within the strategy, interventions in one domain unlock positive developments in other domains. Synergies and possibilities for leverage do exist at the local level, as well as potentials for policy experimentation. More knowledge of how the local economy works and a strong capacity to pursue interdepartmental and multi-level programs are essential requisite to seize the employment and growth potentials of the low-carbon transition.

Les adolescents representent une fraction tres importante des migrants dans les pays en developpement. Cet article cherche a determiner si la migration a l’âge scolaire affecte le niveau de scolarisation des jeunes d’origine rurale. Dans un modele de migration rurale-urbaine, les contraintes de credit et l’incertitude sur les rendements de la scolarite peuvent engendrer un piege de sous-education pour les familles de migrants, avec des effets negatifs sur les investissements scolaires des jeunes. Des donnees longitudinales en provenance de la Thailande montrent que, en moyenne, les jeunes migrants ont des taux d’abandon scolaire plus eleves que les jeunes de la meme generation qui restent dans les villages. Un modele simultane pour l’abandon scolaire et la migration apporte la preuve que cet ecart de scolarisation n’est pas motive par une selection negative (preferences inferieures pour l’enseignement secondaire) des migrants ruraux-urbains. Les resultats indiquent que les couts de l’enseignement superieur sont eleves pour les jeunes qui migrent des campagnes vers les villes, et suggerent la mise en place de politiques de marche du travail et d’education ciblees sur les familles de migrants a faible revenu.Classification JEL : O15, L14

A combination of energy dispersive X-ray fluorescence (ED-XRF) and 2D proton nuclear magnetic resonance ( 1 H NMR) relaxometry was employed for the characterization of two groups of similar ceramic fragments from the high-medieval production of the Phlegrean area (Miseno and Cuma, Southern Italy). Both methods are based on the use of non-destructive and portable instruments. This approach allows to correlate complementary microstructural features of ceramics, both dependent and independent of the firing technique. The ED-XRF analysis has shown up the degree of elemental homogeneity of these two ceramic populations and has lead to reasonable hypotheses about continuity in raw clay source utilization and manufacturing methods over the time period of this Phlegrean ceramic production (VI–XIII centuries A.D.), which have proven coherent with literature data. The NMR investigation has allowed to reveal the structural differences among findings, concerning pore space topology and the magnetic attributes of pore walls. Such differences have been associated to the peculiar interplay between temperature and duration of firing and have proven in step with the temperature assignments provided by archaeologists. This way the usefulness of the proposed methodology for the characterization of the microstructural fingerprint of ancient ceramics has been clearly shown and reliable conclusions about the technological evolution of and the mutual influence between the investigated ceramic productions have been drawn.

Friction stir spot welding (FSSW) has been proposed as an effective technology to spot weld the so-called “difficult to be welded” metal alloys. In the paper, a variation of the FSSW process has been considered. A tool path is given after the sinking phase nearby the initial penetration site; in this way a larger welding spot is obtained and more material is involved in the bonding process. The process mechanics of such modified FSSW process is highlighted and the joint strength undergoing tensile tests is considered at the varying both of the assigned tool path and of a few process parameters. Macro- and micro-analyses are made in order to analyze the local material microstructure evolution. It is found that improved performances, with respect to the “traditional” FSSW process, are obtained for all the considered case studies.

In the paper, a variation of the Friction Stir Spot Welding (FSSW) process has been considered. In particular, a particular tool path is given after the sinking phase nearby the initial penetration site. The process mechanics was highlighted and the joint strength was considered at the varying of the most relevant process parameters. Furthermore macro and micro analyses were developed in order to highlight the process mechanics and the local material microstructure evolution. The investigated technology appears a promising joining technique in order to develop effective spot joints.

The paintings of Andrea Pozzo on the walls and vault of the Refectory in the Convent of Trinita dei Monti in Rome were recently restored. During this process, archaeometric research was carried out on the decorations. Using both restoration observations and the archaeometric analyses, the painting execution methods were examined and compared with Pozzo’s own recommendations in the appendix to his Treatise Perspectiva Pictorum et Architectorum (1693–1702).

Immigration is rapidly changing the composition of the R&D workforce in the United States. We study here Chinese chemists and chemical engineers who migrate to the United States for their graduate studies. We analyze productivity at the individual researcher level, thus bypassing the identification issues that earlier studies had to confront when analyzing the relationship between immigration and innovation at the university or firm level. Using new data and measurement techniques, we find robust evidence that Chinese students make disproportionate contributions to the scientific output of their advisors and departments. We attribute this result to a selection effect as it is relatively more difficult for Chinese students to gain admission to U.S. PhD programs. Our results strengthen the case for liberal student migration policies.

The extent to which income inequality and poverty vary within countries across different regions is very relevant for policy decisions and monitoring. However, sub-national measures are scarce, given the complexity of producing indicators at the regional level from the available data and the methodological issues related to cross-countries comparability. This paper presents a set of indicators of income inequality and poverty across and within regions for 28 OECD countries. These indicators were produced through a new household-level data collection based on internationally harmonized income definitions undertaken as part of the OECD project on “Measuring regional and local well-being for policymaking”. The data were collected at the OECD TL2 territorial level, corresponding to NUTS2 regions in Europe and to large administrative subdivisions (e.g. States in Mexico and Unites States) for non-European countries. These estimates confirm that there are significant variations in levels of income inequality within countries, and that regional breakdowns are useful for understanding sources and patterns of income disparities and poverty. For most of the countries relying on survey data for measuring income distribution, standard cross-sectional indicators of income inequality and relative poverty at this regional level are estimated with low precision in the smallest regions due to small samples. This has two main implications for data producers and analysts. First, systematic reporting of confidence intervals is needed to make meaningful comparisons of inequality levels across regions and with respect to the national averages. Second, averaged measures for multiple years or small area estimation methods should be considered as means for obtaining more robust measures. The issues related to the estimation of standard errors for three-year averages in rotational panel surveys and to the definition of the computational sampling structure for sub-national estimates are discussed in the paper.

The simulation and verification of NC codes for CNC machining is a very important task. The aim of this work is to limit the number of cutting tests needed to verify the right writing of the part program for a CN milling machine in the intent of saving time, human resources and money. This is obtained through the Boolean operation among solids, in AutoCAD environment, of the volume covered by the tool during the operations ruled by the part program.

Low-energy (5-15 eV) electron- and photon-stimulated desorption of KI(100) yields I2P3/2 and 2P1/2 with hyperthermal (0.3 eV) and thermal velocity components. The desorption threshold for both components is 5.3 eV and is correlated with the gamma3/2-exciton long-wavelength edge. Exciton decay at the surface directly produces I2P3/2 and 2P1/2 with hyperthermal velocity and is in competition with self-trapping. Spin memory of the gamma-exciton hole-component is also evident in the hyperthermal channel. An exciton mediated desorption mechanism is presented which is general in alkali halides.

We have studied the electron-stimulated desorption (ESD) of neutral atomic iodine from single crystals of KI(100) using time-of-flight laser-resonance-enhanced multiphoton ionization spectroscopy and quadrupole mass spectrometry. The measured iodine velocity distributions have thermal and non-thermal components. The yield of the thermal component increases with increasing substrate temperature, whereas the yield of the non-thermal component decreases slightly with temperature. The ESD rate for the thermal component decreases with increasing pulse width, unlike the rate for the non-thermal component, which is independent of pulse width. Measurements of ESD yields versus incident electron energy indicate a threshold of ∼5.5 eV. The data collectively indicate that ESD of KI involves exciton decay at the surface. The temperature and pulse-width dependencies of the thermal component are consistent with decay of bulk self-trapped excitons, thermally assisted H-center diffusion and trapping at metastable defects.

Resonant photoemission synchrotron radiation measurements of Fe 3 d states performed on Cd 1− x Fe x Se and Zn 1− x Fe x Se samples, with several x concentrations, are reported. Three Fe-related features have been identified: a weak one located above the top of the host material valence bands and the other two extending over the first 4 eV. The influence of the Se MVV Auger transition is analyzed. The observed features have been discussed in terms of a ligand field approach and assigned to the crystal field levels derived from the Fe 2+ ion final state configurations.

The optical properties of the semiconducting compounds (Me = Ti, V, Cr, Mn, Fe, Co, and Ni) crystallizing in the zinc-blende structure have been investigated. Reflectivity spectra of these materials have been taken at room and liquid nitrogen temperatures. The measurements have been performed in the 4 - 25 eV energy range using synchrotron radiation from the ADONE storage ring in Frascati. Comparisons between the reflectivity spectra of the ternary systems and those of the host crystal ZnSe have been made, and models explaining the influence of the transition metal ions on the electronic structure of the host crystal ZnSe have been discussed.

Important gender gaps in entrepreneurship exist. Men are three times more likely than women to own a business with employees. Women rarely own large businesses and their average earnings from selfemployment are up to 60% lower than for men. Cultural norms, stereotypes and lack of role models make women less interested in an entrepreneurial career and less confident in their capacities as entrepreneurs. Other obstacles such as time shortages and the composition of their professional networks lead women to start relatively small businesses, with low levels of initial capital and bank financing. These obstacles establish a competitive disadvantage for companies owned by women, which translates in levels of labour productivity that are 5 to 30% lower than those of companies owned by men. This paper also presents examples of policy initiatives in the domains of credit, training and awareness raising that can unlock the double dividend of women’s entrepreneurship: higher empowerment of women and more productive businesses. Better data and more analysis are an essential precondition for a more effective implementation of these policies.

The Fe related density of states of Cd 1−x Fe x Se has been investigated by means of synchrotron radiation photoemission. Energy distribution curves of the ternary compound Cd 1−x Fe x Se are presented and compared with those of the binary compound CdSe. Two Fe related structures are easily observed for all photon energies investigated (30 eV – 60 eV), whereas a third structure could be found only in the resonant photoemission region. An analysis of the costant initial state spectra suggests an atomic like interpretation of the experimental observations.

In Integrated Manufacturing Systems (IMS) evaluating the most suitable process plan is a very complex task. Technology, quality, production and market requirements are objectives to be pursued in the selection process, subject to the constraints due to the several part types simultaneously manufactured. The paper proposes a new approach to the process planning selection, based on a possibilistic fuzzy programming model in order to face the vagueness coming from the formalization of the objectives and constraints in the selection problem.

This paper presents recent work undertaken at the OECD to produce environmental indicators at the regional level from geographic data sources. New indicators have been tested and produced in five different domains: a) land cover, b) forest ecosystems, c) urban density, d) CO2 emissions, e) air quality. The indicators measure the environmental performance of administrative regions (OECD TL2 and TL3 regions) and of OECD metropolitan areas. High-quality geographic datasets have been combined and harmonized with the objectives of producing internationally comparable results, and of achieving the largest possible coverage of OECD and non-OECD countries. The results show that geographic information data are a key and underexploited resource for monitoring the state of local environmental assets. There are still methodological and measurement challenges in the use of geographic data for the analysis of environmental changes at the local level. More coordination across national and international programs producing geographic data is needed to further increase their policy relevance.

This chapter sets out a new methodology for defining urban areas, as functional economic places, in a consistent way across countries. The methodology is applied to 28 OECD countries, where more than 1 000 urban areas (with population greater than 50 000) are identified and compared according to their size, form of development, density and population growth. The derivation of a methodology able to describe urban areas can help respond to relevant policy questions. First, it can be used to better analyse the links between urbanisation and economic growth, by taking into account that development does not necessarily imply further increases in the size of the metropolitan areas. Development can occur through a strengthening of linkages among medium-sized urban areas. Second, it opens up to monitoring the quality of life of the people living in urban areas and the sustainable use of resources. The work presented is, thus, meant to be a first step towards the development of a new international dataset aimed at monitoring more inclusive forms of growth and sustainable development of both large and medium-sized urban areas.

Metropolitan areas play a crucial role on the economic performance of countries. They tend to concentrate important shares of the national population and economic activity, but also important shares of innovation, highly educated workers and infrastructures. The 90 largest metropolitan areas in OECD countries, for example, account for around 40 % of OECD population and almost 50 % of its economic activity (OECD 2011).

In this paper we present a comprehensive study of the tetrahedral semiconductor ZnSe crystallizing in the zincblende structure. The electronic structure of ZnSe has been determined first using the ab initio self-consistent linear muffin-tin orbital method with a local-density form of the exchange-correlation functional. Then it has been adjusted to reproduce the experimental energy positions of the Zn 3d bands and of the optical gap. The adjusted electronic structure, densities of states and interband optical properties are presented and compared with previous calculations. Good agreement with experimental photoemission and bremsstrahlung isochromat measurements was found after including an energy-dependent lifetime broadening. We measured the reflectivity of ZnSe with high resolution from 4 to 30 eV and the high-energy region of the spectra has been interpreted on the basis of the present calculation.

Photon stimulated desorption of KI has been measured at several temperatures between 300 K and 485 K using photons in the energy region around the fundamental absorption threshold of KI. The yield spectra vs photon energy of the emission of potassium and iodine atoms are very similar to each other and show a weak structure near threshold, in correspondence of the main exciton absorption peak, followed by a smooth exponential increase, unrelated with the higher energy absorption features of KI. The time dependence of the desorption signal of potassium atoms, measured after turning either on or off the radiation beam, shows the existence of two simultaneous processes with completely different time constants: a ‘fast’ process with a time constant shorter than our time resolution of 0.5 s, and a ‘slow’ process with a time constant of several seconds. The intensity of the slow process is strong at low temperatures and in the region of the main exciton absorption peak, and becomes negligeable at high t...

The authors propose a multiple approach for the evaluation of cutting temperatures in ceramic tools. The first approach was the experimental evaluation of equitemperature lines, obtained in three-dimensional cutting by employing constant melting point powders scattered on planes parallel to rake face. In the second approach, a numerical finite element analysis was performed. At this step the determination of the percentage of total heat produced in the operation that flows into the tool was considered and, consequently, the temperature distribution within the whole volume of the insert. Finally, the examination of the crater zone with SEM microscopy confirmed the temperature levels as previous estimated.

The reflectivity and photoconductivity spectra for mixed crystals Cd1-xFexTe (0.00

The reflectivity spectra of Cd1-xFexSe (x=0, 0.07 and 0.14) have been measured in the energy range 10-25 eV and structures have been assigned to transitions from the Cd 4d and Se 5s states to the conduction bands. The assignment has been supported by theoretical ab-initio calculations of the band structure and the optical properties of pure hypothetical zincblende CdSe. The band structure and the density of states have been obtained using the self-consistent relativistic LMTO method. The theoretical spectrum has been calculated with the inclusion of k-dependent transition matrix elements. The energy shifts of the maxima as the Fe concentration increases have been discussed.

The excavation of Piano di Comunità in the Etruscan town of Veii, has brought to light a pit of the preroman period, which was filled at the beginning of the IIIrd century b.C. with a huge amount of pottery and terracotta fragments. The pottery - mainly bucchero and fine creamware - is representative of the production of the archaic and late-archaic period. Thanks to the collaboration between the University "Roma Tre", the University "La Sapienza" of Rome and the C.N.R., and thanks to the possibility of applying different methods of analysis, a comparative study was undertaken in order to bring light to the main technical features of the pottery from the pit. Samples of depurated pottery (bucchero, fine creamware) were compared in order to determine their structural clay characteristics and to better understand the organization of the workshops of the period (e.g., exploitation of local resources or choice of imported raw materials). At the same time, two imported fragments were also analysed and allowed to point out diagnostic chemical elements. Furthermore, samples of terracottas and impasto were analysed together with fine pottery samples in order to carry out a detailed study on painted decoration. The different methods applied have produced the same kind of results. As regards the choice of raw materials, analyses have stressed the peculiar composition of bucchero clay, apparently imported from some distance, whereas the fine creamware pottery show "local" features; as regards this question, sampling of clay beds in the immediate surroundings of Veii has been planned. As regards the painted decorations, the obtained data show that black and red were commonly produced using clay with higher manganese and iron contents; the use of pigments was quite rare and possibly reserved to terracottas only.

We present the excitation spectra of KI:T1 measured in the region of the B and C absorption bands at several emission wavelengths and at 20 K, 80 K and 300 K. An accurate analysis of these spectra shows new properties of the excitation spectra, that we relate to the non radiative relaxation of the excited electrons towards the luminescent states.

A new technique for the on-line control of the surface roughness in the finish turning operation is presented. By means of tool image detection and processing, the ideal roughness profile that the tool should produce on the workpiece is evaluated. A model to estimate the value of the effective roughness of the workpiece from one related to the ideal profile is proposed. This model is not significantly influenced by the feed employed.

This paper investigates the presence of a network externality which might explain the persistence of low schooling achievements among internal migrants. A simple analytical framework is presented to show how an initial human capital disparity between migrants and non migrants can translate into persistent skill inequality if origin shapes the composition of social networks. We test empirically whether young migrants�schooling decisions are affected by the presence of covillagers at destination, using data on life-time histories of migration and education choices from a rural region of Thailand. Different modelling approaches are used to account for the self-selection of young migrants, for potential endogeneity of the network size, and for unobserved heterogeneity in individual preferences. The size of the migrant network is found to negatively affect the propensity of young migrants to pursue schooling while in the city. This fi�nding suggests that policies seeking to minimising strati�cation in enclaves might have a socially multiplied impact on schooling participation, and, ultimately, affect the socio-economic mobility of the rural born.

In the recent years Friction Stir Welding (FSW) has become an important joining technique since it allows to weld light weight alloys rather difficult to be welded or even “un-weldable” with the classic fusion welding operations. In the paper the authors present the application of the FSW process to the joining of 3D complex shapes typical of the industrial environment. In particular the research was aimed to highlight the joint mechanical strength at the varying of the 3D geometry of the welding line.Copyright © 2006 by ASME

IL MARMO NERO DI CARLO MAGNO: L'ORIGINE DELL'EPITAFFIO DI PAPA ADRIANO IQuesto articolo presenta nuove evidenze che identificano l'origine del marmo nero dell'epitaffio di papa Adriano I, conservato attualmente nel portico di San Pietro in Vaticano. L'epitaffio fu commissionato da Carlo Magno dopo la morte di Adriano (avvenuta il 26 dicembre del 795) ed è il più eminente esempio attualmente esistente di epigrafia carolingia. È un pezzo maestro del rinascimento carolingio. Questo articolo dimostra attraverso analisi paleontologiche, petrologiche e geochimiche che la pietra per l'epitaffio fu cavata nei pressi del flume Meuse, vicino Namur in Belgio, in un'area situata all'interno delle estese proprietà della famiglia Carolingia. Inoltre, si deduce che la pietra nera fu scelta con il consapevole intento d'imitare le espressioni classiche delle risorse imperiali, e che unitamente all'indubbia qualita dell'epigrafe e del testo poetico, la scelta del marmo può essere interpretata come una testimonianza di eredità culturale e ambizione imperiale da parte del suo patrono, che fu incoronato Imperatore in Roma nel natale dell'800, in un luogo dal quale era possibile vedere l'iscrizione, cinque anni dopo la morte di Adriano.

XRF and micro-Raman stratigraphic microanalyses of fragments of some mural paintings, belonging to the Archaeological Site of Oplonti (Napoli) and the Vigna Barberini site in the Palatino (Roma), were performed. In order to collimate the fluorescence X-rays emitted by the samples, an X-ray polycapillary conic collimator (PCC) has been used in front of the detector. This device arrangement is compact, versatile, and portable. The nature of the pigments, the compositional elements, and the thickness of the fragment layers have been studied. The stratigraphic analysis partially confirms the preparation techniques described by Plinius and Vitruvius; moreover it confirms the hypothesis that the artifacts are not fresco paintings. This work has been conducted within the context of a wider research on the Roman age mural paintings.

In this paper the performances of some commercial ceramic inserts when cutting AISI 310 steel are investigated and compared to those of a traditional carbide based tool. The most important wear mechanism in the ceramic inserts is related to the segmented edges of the chips that abrade a notch at the end of the cut zone. Alumina–zirconia inserts are very sensitive to this kind of wear, whereas tools made of Sialon and alumina with SiC whiskers exhibit slightly better performances despite the concomitant chemical wear mechanisms.

In finish turning operation, it has already shown, that for the sake of control the dimensional accuracy and the micro-geometry of the worked surface, the wear parameters employed in rough turning operations are not suitable. In the present work the study of wear in fmish turning operations, is carried out, employing a particular groove survey methodology, already proposed in a previous paper, that is based on the techniques of acquirement and processing of images. In order to verify the applicability of the proposed technique two kind of alumina-based inserts and two kind of sintered carbide inserts have been tested. The experimental tests have confirmed the validity of the technique in the prediction of tool lifetimes for several couples toolworkpiece materials.

The ejection of atoms and molecules from the surface of solids subject to the bombardment of energetic particles is a well known phenomenon that is employed routinely in laboratories and industrial plants for cleaning a surface, determining surface composition or ejecting material from a solid for deposition on adjacent targets. This emission, called sputtering, is the result of a direct momentum transfer from the incident particles to the atoms of the solid.

A new on-line control method for the wear state of sintered carbide tools for finish turning operations is proposed.