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O Vidro Pré-Romano no Norte de Portugal

Gomes, Hugo Fernando Parracho
Fonte: [s.n.] Publicador: [s.n.]
Tipo: Dissertação de Mestrado
Publicado em //2012 POR
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Dissertação apresentada à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Arqueologia; O presente trabalho tem como objectivo principal contribuir para o estudo e conhecimento das sociedades do Noroeste Peninsular português, integradas na área de influência da chamada “Cultura Castreja”, ao longo do I Milénio a.C., até aos inícios do domínio romano, utilizando como ponto de partida e objecto de estudo os artefactos em vidro que foram até à data encontrados. Concretamente, procuraremos compreender de que forma o espólio vítreo se enquadra no conjunto de estímulos exógenos que terão sido sentidos pelas populações desta região no decurso deste período e que terão determinado o curso evolutivo das sociedades locais e contribuído para a singularidade da chamada “Cultura dos Castros”. Do ponto de vista geográfico, o estudo abrangerá a tradicional área de influência da “Cultura Castreja”, excluindo o território espanhol a Norte do Rio Minho, apresentando os seguintes limites: o rio Vouga, a Sul; o rio Minho, a Norte; o Oceano Atlântico a Oeste; os rios Tua e Rabaçal a Este. O vidro deste período encontrado em Portugal não foi ainda alvo de qualquer tipo de estudo ou abordagem sistemática pelo que se tratou de um trabalho pioneiro que implicou a realização de um inventário exaustivo dos materiais encontrados e o seu estudo morfo-tipológico. Do trabalho realizado resultou um aumento significativo do número de sítios com objectos de vidro pré-romanos face aos levantamentos anteriormente realizados...

Quantum critical scaling at a Bose-glass/superfluid transition: Theory and experiment for a model quantum magnet

Yu, Rong; Miclea, Corneliu F.; Weickert, Franziska; Movshovich, Roman; Paduan Filho, Armando; Zapf, Vivien S.; Roscilde, Tommaso
Fonte: AMER PHYSICAL SOC; COLLEGE PK Publicador: AMER PHYSICAL SOC; COLLEGE PK
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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In this paper we investigate the quantum phase transition from magnetic Bose Glass to magnetic Bose-Einstein condensation induced by amagnetic field in NiCl2 center dot 4SC(NH2)(2) (dichloro-tetrakis-thiourea-nickel, or DTN), doped with Br (Br-DTN) or site diluted. Quantum Monte Carlo simulations for the quantum phase transition of the model Hamiltonian for Br-DTN, as well as for site-diluted DTN, are consistent with conventional scaling at the quantum critical point and with a critical exponent z verifying the prediction z = d; moreover the correlation length exponent is found to be nu = 0.75(10), and the order parameter exponent to be beta = 0.95(10). We investigate the low-temperature thermodynamics at the quantum critical field of Br-DTN both numerically and experimentally, and extract the power-law behavior of the magnetization and of the specific heat. Our results for the exponents of the power laws, as well as previous results for the scaling of the critical temperature to magnetic ordering with the applied field, are incompatible with the conventional crossover-scaling Ansatz proposed by Fisher et al. [Phys. Rev. B 40, 546 (1989)]. However they can all be reconciled within a phenomenological Ansatz in the presence of a dangerously irrelevant operator.; UEFISCDI [PN-II-ID-PCE-2011-3-1028]; UEFISCDI; DOE (INCITE award); DOE (INCITE award); Laboratory Directed Research and Development program at Los Alamos; Laboratory Directed Research and Development program at Los Alamos [20100043DR]

A COMBINED MULTI-ANALYTICAL APPROACH FOR THE STUDY OF ROMAN GLASS FROM SOUTH-WEST IBERIA: SYNCHROTRON m-XRF, EXTERNAL-PIXE/PIGE AND BSEM–EDS

Carneiro, André; Schiavon, N; Candeias, A; Ferreira, T; Calligaro, T; Lopes, C; Mirão, J
Fonte: Archaeometry Publicador: Archaeometry
Tipo: Artigo de Revista Científica
ENG
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An integrated, multi-analytical approach combining the high sensitivity of SR-mXRF, the light element capability of PIXE/PIGE under a helium flux and the spatial resolution of BSEM + EDS was used to characterize chemical composition and corrosion of glass samples (first to fourth centuries AD) from an important, but scarcely investigated, Roman region of south-west Iberia (southern Portugal). The geochemical trends and associations of major, minor and trace elements were investigated to shed light on production techniques, the provenance of raw materials and decay mechanisms. The results, while confirming a produc- tion technique common to Roman glasses throughout the Empire—that is, a silica-soda-lime low-Mg, low-K composition, with glass additives as colouring and/or decolouring agents (Fe, Cu, Mn, Sb)—show at one site high Zr–Ti contents, suggesting a more precise dating for these glasses to the second half of the fourth century. The Ti–Fe–Zr–Nb geochemical correlations in the pristine glass indicate the presence of minerals such as ilmenite, zircon, Ti-rich Fe oxides and columbite in the sands used as raw materials for the glass former: these minerals are typical of granitic-type source rocks. The unusually high K content in the corrosion layers is consistent with burial conditions in K-rich soils derived from the alteration of 2:1 clays in K-bearing rock sequences.

A COMBINED MULTI-ANALYTICAL APPROACH FOR THE STUDY OF ROMAN GLASS FROM SOUTH-WEST IBERIA: SYNCHROTRON micro-XRF, EXTERNAL-PIXE/PIGE AND BSEM–EDS

SCHIAVON, N.; CANDEIAS, A.; FERREIRA, T.; LOPES, M. DA CONCEIÇAO; CARNEIRO, A.; CALLIGARO, T.; MIRAO, J.
Fonte: wiley Publicador: wiley
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
58.07672%
An integrated, multi-analytical approach combining the high sensitivity of SR-mXRF, the light element capability of PIXE/PIGE under a helium flux and the spatial resolution of BSEM + EDS was used to characterize chemical composition and corrosion of glass samples(first to fourth centuries AD) from an important, but scarcely investigated, Roman region of south-west Iberia (southern Portugal). The geochemical trends and associations of major, minor and trace elements were investigated to shed light on production techniques, the provenance of raw materials and decay mechanisms. The results, while confirming a production technique common to Roman glasses throughout the Empire—that is, a silica-soda-lime low-Mg, low-K composition, with glass additives as colouring and/or decolouring agents (Fe,Cu, Mn, Sb)—show at one site high Zr–Ti contents, suggesting a more precise dating for these glasses to the second half of the fourth century. The Ti–Fe–Zr–Nb geochemical correlations in the pristine glass indicate the presence of minerals such as ilmenite, zircon, Ti-rich Fe oxides and columbite in the sands used as raw materials for the glass former: these minerals are typical of granitic-type source rocks. The unusually high K content in the corrosion layers is consistent with burial conditions in K-rich soils derived from the alteration of 2:1 clays in K-bearing rock sequences.

Spine-Ghost: A New Bioactive Cement for Vertebroplasty

Vitale-Brovarone, Chiara; Pontirolli, Lucia; Novajra, Giorgia; Tcacencu, Ion; Reis, Joana; Manca, Antonio
Fonte: Key Engineering Materials Publicador: Key Engineering Materials
Tipo: Artigo de Revista Científica
ENG
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An innovative, resorbable and injectable composite cement (Spine-Ghost) to be used for augmentation and restoration of fractured vertebrae was developed. Type III α-calcium sulfate hemihydrate (CSH) was selected as the bioresorbable matrix, while spray-dried mesoporous bioactive particles (SD-MBP, composition 80/20% mol SiO2/CaO), were added to impart high bioactive properties to the cement; a glass-ceramic containing zirconia was chosen as a second dispersed phase, in order to increase the radiopacity of the material. After mixing with water, an injectable paste was obtained. The developed cement proved to be mechanically compatible with healthy cancellous bone, resorbable and bioactive by soaking in simulated body fluid (SBF), cytocompatible through in-vitro cell cultures and it could be injected in ex-vivo sheep vertebra. Comparisons with a commercial control were carried out.

Composition, Production and Procurement of Glass at San Vincenzo al Volturno: An Early Medieval Monastic Complex in Southern Italy

Schibille, Nadine; Freestone, Ian C.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 16/10/2013 EN
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136 glasses from the ninth-century monastery of San Vincenzo and its workshops have been analysed by electron microprobe in order to situate the assemblage within the first millennium CE glass making tradition. The majority of the glass compositions can be paralleled by Roman glass from the first to third centuries, with very few samples consistent with later compositional groups. Colours for trailed decoration on vessels, for vessel bodies and for sheet glass for windows were largely produced by melting the glass tesserae from old Roman mosaics. Some weakly-coloured transparent glass was obtained by re-melting Roman window glass, while some was produced by melting and mixing of tesserae, excluding the strongly coloured cobalt blues. Our data suggest that to feed the needs of the glass workshop, the bulk of the glass was removed as tesserae and windows from a large Roman building. This is consistent with a historical account according to which the granite columns of the monastic church were spolia from a Roman temple in the region. The purported shortage of natron from Egypt does not appear to explain the dependency of San Vincenzo on old Roman glass. Rather, the absence of contemporary primary glass may reflect the downturn in long-distance trade in the later first millennium C.E....

Late Roman glass from the 'Great Temple' at Petra and Khirbet Et-Tannur, Jordan - technology and provenance

Schibille, N.; Degryse, P.; O'Hea, M.; Izmer, A.; Vanhaecke, F.; McKenzie, J.
Fonte: Oxford Univ Publicador: Oxford Univ
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
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Forty-seven window and vessel glasses from the 'Great Temple' at Petra (Jordan), dating to the first/second and fourth centuries ce, were analysed by EPMA for major and minor elements. A subset of 29 samples from Petra and 15 samples from Khirbet et-Tannur were additionally analysed for trace elements, using LA–ICP–MS. Six compositional groups were identified on the basis of the presence of decolouring agents. The majority of the glasses derive ultimately from the Levantine coast, but most of the groups show evidence for highly selective recycling. The observed differences between the two sites could be related to different chronological ranges, functions, relative wealth and trade connections.; N. Schibille, P. Degryse, M. O'Hea, A. Izmer and F. Vanhaecke

Bose glass and Mott glass of quasiparticles in a doped quantum magnet

Yu, Rong; Yin, Liang; Sullivan, Neil S.; Xia, J. S.; Huan, Chao; Paduan Filho, Armando; Oliveira Junior, Nei Fernandes de; Haas, Stephan; Steppke, Alexander; Miclea, Corneliu F.; Weickert, Franziska; Movshovich, Roman; Mun, Eun-Deok; Scott, Brian L.; Zapf
Fonte: NATURE PUBLISHING GROUP; LONDON Publicador: NATURE PUBLISHING GROUP; LONDON
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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The low-temperature states of bosonic fluids exhibit fundamental quantum effects at the macroscopic scale: the best-known examples are Bose-Einstein condensation and superfluidity, which have been tested experimentally in a variety of different systems. When bosons interact, disorder can destroy condensation, leading to a 'Bose glass'. This phase has been very elusive in experiments owing to the absence of any broken symmetry and to the simultaneous absence of a finite energy gap in the spectrum. Here we report the observation of a Bose glass of field-induced magnetic quasiparticles in a doped quantum magnet (bromine-doped dichloro-tetrakis-thiourea-nickel, DTN). The physics of DTN in a magnetic field is equivalent to that of a lattice gas of bosons in the grand canonical ensemble; bromine doping introduces disorder into the hopping and interaction strength of the bosons, leading to their localization into a Bose glass down to zero field, where it becomes an incompressible Mott glass. The transition from the Bose glass (corresponding to a gapless spin liquid) to the Bose-Einstein condensate (corresponding to a magnetically ordered phase) is marked by a universal exponent that governs the scaling of the critical temperature with the applied field...

O vidro romano no Noroeste Peninsular : um olhar a partir de Bracara Augusta

Cruz, Mário da
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Tese de Doutorado
Publicado em 16/11/2009 POR
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Tese de doutoramento em Arqueologia (área de conhecimento de Materiais e Tecnologias); “Vidros Romanos no Noroeste Peninsular. Um olhar a partir de Bracara Augusta” começou pelo estudo da importante colecção de vidros de Braga e estendeu-se às pequenas e grandes colecções, guardadas em museus, gabinetes municipais de arqueologia e outras instituições, publicas e privadas, no que outrora fora a província romana da Callaecia. Esta tese procurou ir para além dos tradicionais estudos de vidros, baseados em descrições e classificações tipológicas, procurando estudar todas as facetas do vidro antigo, desde os estudos de arqueometria à produção local. Este novo olhar trouxe ao de cima uma nova realidade e procurou ultrapassar velhas noções baseadas em conhecimentos da indústria vidreira Medieval e Moderna. Um novo conceito, relativo à importância do vidro no quotidiano das populações e na economia do noroeste peninsular, emergiu.; “Roman glass from the Iberian Peninsula’s northwest. An approach from Bracara Augusta” begins with the analysis of the important glass collection from Bracara Augusta, the modern town of Braga, and continues with the study of other collections kept in museums and archaeological institutes in what was the Roman province of Callaecia. This thesis goes beyond the traditional study of glass vessels based on descriptions and classifications...

'Cold' crystallization in nanostructurized 80GeSe2-20Ga2Se3 glass

Klym, Halyna; Ingram, Adam; Shpotyuk, Oleh; Calvez, Laurent; Petracovschi, Elena; Kulyk, Bohdan; Serkiz, Roman; Szatanik, Roman
Fonte: Springer US Publicador: Springer US
Tipo: Artigo de Revista Científica
Publicado em 06/02/2015 EN
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'Cold' crystallization in 80GeSe2-20Ga2Se3 chalcogenide glass nanostructurized due to thermal annealing at 380°C for 10, 25, 50, 80, and 100 h are probed with X-ray diffraction, atomic force, and scanning electron microscopy, as well as positron annihilation spectroscopy performed in positron annihilation lifetime and Doppler broadening of annihilation line modes. It is shown that changes in defect-related component in the fit of experimental positron lifetime spectra for nanocrystallized glasses testify in favor of structural fragmentation of larger free-volume entities into smaller ones. Nanocrystallites of Ga2Se3 and/or GeGa4Se8 phases and prevalent GeSe2 phase extracted mainly at the surface of thermally treated samples with preceding nucleation and void agglomeration in the initial stage of annealing are characteristic features of cold crystallization.

Dielectric study of the glass transition of PET/PEN blends

Sellares, J.; Diego, J. A.; Canadas, J. C.; Mudarra, M.; Belana, J.; Colomer, P.; Roman, F.; Calventus, Y.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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An analysis of the glass transition of four materials with similar chemical structures is performed: PET, PEN and two PET/PEN blends (90/10 and 70/30 w/w). During the melt processing of the blends transesterification reactions yield block and random PET/PEN copolymers that act as compatibilizers. The blends obtained in this way have been characterized by 1H-NMR and DSC. A degree of randomness of 0.38 and 0.26 has been found for the 90/10 and 70/30 copolymers. It is shown by DSC that this copolimerization is enough to compatibilize the blends. The alpha relaxation, the dielectric manifestation of the glass transition, has been studied by thermally stimulated depolarization currents (TSDC). The relaxation has been analyzed into its elementary modes by means of a relaxation map analysis. The activation energies of the modes of the glass transition do not change significantly between the four materials: in all cases the modes with a larger contribution have around 3 eV and modes with less than 1 eV are not detected. The change in the pre-exponential factor accounts entirely for the relaxation time change from material to material, that is larger as the PEN content increases. The compensation law is fulfilled and compensation plots converge for high-frequency modes. The polarizability decreases as the PEN content increases due to the increased stiffness of the polymer backbone. An analysis of the cooperativity shows that the central modes of the distribution are the most cooperative while high-frequency modes tend to behave more as Arrhenius. The low-frequency modes are difficult to study due to the asymmetry of the distribution of relaxation times. PEN turns out to be the less cooperative material. It is demonstrated how the parameters obtained from the dielectric study are able to reproduce calorimetric data from DSC scans and are...

Electron irradiation induced reduction of the permittivity in chalcogenide glass (As2S3) thin film

San-Román-Alerigi, Damián P.; Anjum, Dalaver H.; Zhang, Yaping; Yang, Xiaoming; Benslimane, Ahmed; Ng, Tien K.; Alsunaidi, Mohammad; Ooi, Boon S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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We investigate the effect of electron beam irradiation on the dielectric properties of As2S3 Chalcogenide glass. By means of low-loss Electron Energy Loss Spectroscopy, we derive the permittivity function, its dispersive relation, and calculate the refractive index and absorption coefficients under the constant permeability approximation. The measured and calculated results show, to the best of our knowledge, a heretofore unseen phenomenon: the reduction in the permittivity of <40%, and consequently a modification of the refractive index follows, reducing it by 20%, hence suggesting a significant change on the optical properties of the material. The plausible physical phenomena leading to these observations are discussed in terms of the homopolar and heteropolar bond dynamics under high energy absorption.; Comment: 22 pages, 7 figures, manuscript in preparation to send to Physical Review B

Quantum critical scaling at a Bose-glass/superfluid transition: theory and experiment on a model quantum magnet

Yu, Rong; Miclea, Corneliu F.; Weickert, Franziska; Movshovich, Roman; Paduan-Filho, Armando; Zapf, Vivien S.; Roscilde, Tommaso
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/04/2012
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37.060051%
In this paper we investigate the quantum phase transition from magnetic Bose glass to magnetic Bose-Einstein condensation induced by a magnetic field in NiCl2.4SC(NH2)2 (dichloro-tetrakis-thiourea-Nickel, or DTN), doped with Br (Br-DTN) or site diluted. Quantum Monte Carlo simulations for the quantum phase transition of the model Hamiltonian for Br-DTN, as well as for site-diluted DTN, are consistent with conventional scaling at the quantum critical point and with a critical exponent z verifying the prediction z=d; moreover the correlation length exponent is found to be nu = 0.75(10) and the order parameter exponent to be beta = 0.95(10). We investigate the low-temperature thermodynamics at the quantum critical field of Br-DTN both numerically and experimentally, and extract the power-law behavior of the magnetization and of the specific heat. Our results for the exponents of the power laws, as well as previous results for the scaling of the critical temperature to magnetic ordering with the applied field, are incompatible with the conventional crossover-scaling Ansatz proposed by Fisher et al., [Phys. Rev. B 40, 546 (1989)], but they can all be reconciled within a phenomenological Ansatz in the presence of a dangerously irrelevant operator.; Comment: 12 pages...

Bose glass and Mott glass of quasiparticles in a doped quantum magnet

Yu, Rong; Yin, Liang; Sullivan, Neil S.; Xia, J. S.; Huan, Chao; Paduan-Filho, Armando; Oliveira Jr., Nei F.; Haas, Stephan; Steppke, Alexander; Miclea, Corneliu F.; Weickert, Franziska; Movshovich, Roman; Mun, Eun-Deok; Zapf, Vivien S.; Roscilde, Tommaso
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
37.47742%
The low-temperature states of bosonic fluids exhibit fundamental quantum effects at the macroscopic scale: the best-known examples are Bose-Einstein condensation (BEC) and superfluidity, which have been tested experimentally in a variety of different systems. When bosons are interacting, disorder can destroy condensation leading to a so-called Bose glass. This phase has been very elusive to experiments due to the absence of any broken symmetry and of a finite energy gap in the spectrum. Here we report the observation of a Bose glass of field-induced magnetic quasiparticles in a doped quantum magnet (Br-doped dichloro-tetrakis-thiourea-Nickel, DTN). The physics of DTN in a magnetic field is equivalent to that of a lattice gas of bosons in the grand-canonical ensemble; Br-doping introduces disorder in the hoppings and interaction strengths, leading to localization of the bosons into a Bose glass down to zero field, where it acquires the nature of an incompressible Mott glass. The transition from the Bose glass (corresponding to a gapless spin liquid) to the BEC (corresponding to a magnetically ordered phase) is marked by a novel, universal exponent governing the scaling on the critical temperature with the applied field, in excellent agreement with theoretical predictions. Our study represents the first...

Análisis de vidrios romanos del yacimiento de la Dehesa de la Oliva (Patones, Madrid); Analysis of roman glasses from the Dehesa de la Oliva (Patones, Madrid)

Carmona, N.; Villegas Broncano, María Ángeles; Castellanos, M. A.; Montero Ruiz, Ignacio; García Heras, Manuel
Fonte: Consejo Superior de Investigaciones Científicas (España) Publicador: Consejo Superior de Investigaciones Científicas (España)
Tipo: Comunicación de congreso Formato: 3281884 bytes; application/pdf
SPA
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[ES] Este trabajo presenta los resultados obtenidos en el estudio arqueométrico de un conjunto de vidrios romanos hallados en las distintas campañas de excavación arqueológica realizadas en el yacimiento de La Dehesa de la Oliva (Patones, Madrid). Los objetivos se centraron en determinar la composición química de los vidrios pertenecientes a las dos fases principales de ocupación y comprobar si existían diferencias entre ellos, así como evaluar su estado de conservación. También se caracterizaron sus coloraciones mediante el análisis de sus cromóforos. El estudio se realizó con las siguientes técnicas: microscopía óptica, fluorescencia de rayos X (FRX), microscopía electrónica de barrido de emisión de campo (MEBEC), microanálisis de dispersión de energía de rayos X (EDX) y espectrofotometría ultravioleta-visible (UV-VIS). Los datos obtenidos indicaron que todos los vidrios analizados eran de silicato sódico-cálcico, con composiciones químicas muy semejantes. Las coloraciones se atribuyeron a iones hierro aportados como impurezas de las materias primas. Finalmente, los vidrios mostraron un estado de alteración medio con presencia de picaduras, irisaciones y desalcalinización superficial.; [EN] This work reports the results derived from a characterisation study undertaken on a sample set of Roman glasses found in some archaeological fieldworks carried out in La Dehesa de la Oliva site (Patones...

Estudio arqueométrico de cuentas de vidrio procedentes de la necrópolis de Numancia (siglo II a.C.)

García Heras, Manuel; Villegas Broncano, María Ángeles; Jimeno Martínez, Alfredo; Rincón López, Jesús María
Fonte: Consejo Superior de Investigaciones Científicas (España) Publicador: Consejo Superior de Investigaciones Científicas (España)
Tipo: Artículo Formato: 1831170 bytes; application/pdf
SPA
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[ES] La reciente excavación de la necrópolis celtibérica de Numancia (Garray, Soria) ha permitido recuperar un conjunto de cuentas de vidrio del siglo Ha.C. Las cuentas,junto conotros objetos de metaly cerámica, formaban parte de las ofrendas depositadas con el difunto, siendo de tipología anular y coloreadas en azul oscuro,ambar y blanco semitransparente. Este trabajo presenta los resultados obtenidos en la caracterización química y microestructural de una muestra representativa de este conjunto. El objetivo principal de la investigación consistió en recabar información sobre su tecnología de manufactura y evaluar su posible procedencia. Asimismo, también se investigaron sus mecanismos de corrosión para determinar si la cremación había inducido cambios en su estructura. Los resultados indican que las cuentas azules y ámbar se realizaron con vidrio de silicato sódico cálcico y las blancas semitransparentes con vidrio de aluminosilicato, utilizando óxidos de metales de transición como cromóforos y óxido de plomo para la decoración.; [EN] Recent archaeologícal field work undertaken ín the Celtiberian cremation necropolis of Numantia (Soria, Spain) has provided a group of glass beads from the 2nd century BC. Such glass beads were part...

El vidrio en la civilización egipcia. Descripción de piezas de vidrio del tipo incrustaciones de una colección de la Universidad de Sevilla; The glass in the Egyptian civilization. Description of glass elements considered as glass inlays of an Egyptian Collection of the University of Sevilla

Ruíz-Conde, Antonio; Sánchez-Soto, Pedro José; Villegas Broncano, María Ángeles; Seco Álvarez, M.
Fonte: Sociedad Española de Cerámica y Vidrio Publicador: Sociedad Española de Cerámica y Vidrio
Tipo: Artículo Formato: 204626 bytes; application/pdf
SPA
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[ES] En el presente trabajo, se destaca la importancia que la manufactura y el arte del vidrio tuvo para la civilización egipcia. Se describe a grandes rasgos su evolución histórica y los principales métodos de fabricación. A continuación, se resalta la existencia de una serie de materiales vítreos, denominados genéricamente incrustaciones, que en la época egipcia tuvieron diversos fines, todos ellos de elevado nivel artístico, como son pequeños amuletos, piezas de joyería y otras aplicaciones, entre ellos las máscaras y los cartonajes. Dichos materiales podrían ser precedentes del mosaico vidriado. Como ejemplo de interés de este tipo de manufactura, se han seleccionado una serie de incrustaciones en vidrio procedentes de una colección de Arte Egipcio de la Universidad de Sevilla con el objetivo de darla a conocer. Se describen dichas piezas y se lleva a cabo una discusión crítica sobre las características de las mismas. Los resultados obtenidos en la descripción de estas piezas se relacionan con información disponible en una serie de fuentes bibliográficas sobre incrustaciones, por ejemplo las de vidrio monocromático del Museo Grecorromano de Alejandría, Museo Británico y Museo Egipcio de El Cairo.; [EN] In this work...

Estudio arqueométrico de muestras procedentes de mosaicos romanos de Itálica y Carmona (Sevilla)

Palomar, Teresa
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em //2011 SPA
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Jornadas de Jóvenes en Investigación Arqueológica, JIA (3as : 5-7 de mayo 2010 : Universitat Autònoma de Barcelona). Sesión 11. “Estudios arqueométricos".; Este trabajo presenta los resultados del estudio arqueométrico realizado en muestras de mosaicos romanos procedentes de Itálica y Carmona (Sevilla). El objetivo principal del estudio consistió en la caracterización químico-física de teselas de vidrio y fragmentos de mortero para determinar su composición, evaluar su estado de conservación y estudiar su tecnología de fabricación. Las muestras se caracterizaron mediante lupa binocular, microscopía electrónica de barrido y microanálisis de dispersión de energía de rayos X, espectrofotometría visible, difracción de rayos X y análisis petrográfico. Los resultados indicaron que las teselas se realizaron con vidrio de silicato sódico cálcico, aunque una de ellas mostró elevados contenidos de óxidos de plomo y cobre. Las muestras procedentes de Itálica presentaron una menor degradación que las de Carmona, como consecuencia de la humedad retenida por el mosaico. Asimismo, los resultados indicaron que en las teselas se utilizó un vidrio de inferior calidad técnica que el empleado en piezas de vajilla.; This work reports results of the archaeometric study carried out on Roman mosaic samples from Italica and Carmona (Spain). The main objective of the research was the chemical-physical characterization of both glass tesserae and mortar fragments to determine their composition...

Diatreta as life form

Kim, Joon Yong
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
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N/A; This thesis investigates "Diatreta", a Roman glass technique from the third century A.D. The investigation if this technique challenged the limitations that are inherent in glass working. The Diatreta is a vessel in which an outer layer has been carved away to leave an open network that is joined to the inner layer by fine glass struts. This form is investigated a a metaphor for personal identity as well as embodying the nature of the human condition.

Determination of the minimun integral entropy, water sorption and glass transition temperature to establishing critical storage condition of beetroot juice microcapsules by spray drying

Guadarrama-Lezama,A.Y.; Cruz-Olivares,J.; Martínez-Vargas,S.L.; Carrillo-Navas,H.; Román-Guerrero,A.; Perez-Alonso,C.
Fonte: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería Publicador: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 EN
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The aim of this work was to microencapsulate beetroot juice (BJ) (Beta vulgaris L.) by spray-drying using as protective colloid gum Arabic. The adsorption isotherms of the microcapsules and the minimum integral entropy (ΔSint)T were determined at 25, 35 and 40 °C. The glass transition temperature (Tg) was measured by differential scanning calorimetry and modeled by Gordon-Taylor equation. The water contents-water activity (M-aW) sets obtained from (ΔSint)T, and critical water content (CWC) and critical water activity (CWA) from the Tg were similar, being in the range of water content of 5.11-7.5 kg H2O/100 kg d.s. and in the water activity range of 0.532-0.590. These critical storage conditions were considered as the best conditions for increase the stability of the microcapsules, where the percentage of retention Betanin in the microcapsules was higher compared with other storage conditions in the temperature and a w range studied.