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Sample records for tetragonal tungstenio bronze

  1. Crystallography properties of solid solution of NaSr{sub 2}(NiNb{sub 4})O{sub 15-{delta}s}tructure of tetragonal tungsten bronze; Propriedades cristalograficas da solucao de NaSr{sub 2}(NiNb{sub 4})O{sub 15-{delta}} de estrutura tetragonal tungstenio bronze

    Energy Technology Data Exchange (ETDEWEB)

    Polini, C.; Dantas, S.A.; Mikaro, C.; Lima, A.R.F.; Nobre, M.A.L.; Lanfredi, S. [Universidade Estadual Paulista (LaCCeF/UNESP), Presidente Prudente, SP (Brazil). Dept. de Fisica, Quimica e Biologia. Lab. de Compositos e Ceramicas Funcionais

    2009-07-01

    In this work was investigated the crystallographic characterization of single phase and nanometric powders of sodium strontium niobate doped with nickel, with NaSr{sub 2}(NiNb{sub 4})O{sub 15-{delta}} stoichiometry, prepared by conventional route from mechanical mixture of oxides / carbonates using the high energy ball milling. The optimization of the parameters as time and calcination temperature for the preparation of the NaSr{sub 2}(NiNb{sub 4})O{sub 15-{delta}} solid solution were monitored by X-ray diffraction, using the Rietveld method. The NaSr{sub 2}(NiNb{sub 4})O{sub 15-{delta}} single phase powders with tetragonal tungsten bronze type structure were obtained with crystallite size at around 30 nm. From crystallographic parameters was constructed the unitary cellule of the NaSr{sub 2}(NiNb{sub 4})O{sub 15-{delta}} using the CaRIne Crystallography 3.1 program. The occupation of sites by the Na{sup +} and Sr{sup 2+} cations and the interatomic distances between nickel and niobium atoms were determined. Changes in structural parameters of sodium strontium niobate by addition of nickel are discussed. (author)

  2. High-pressure synthesis of fully occupied tetragonal and cubic tungsten bronze oxides

    Energy Technology Data Exchange (ETDEWEB)

    Ikeuchi, Yuya; Takatsu, Hiroshi; Tassel, Cedric; Goto, Yoshihiro; Murakami, Taito; Kageyama, Hiroshi [Graduate School of Engineering, Kyoto University (Japan)

    2017-05-15

    A high-pressure reaction yielded the fully occupied tetragonal tungsten bronze K{sub 3}W{sub 5}O{sub 15} (K{sub 0.6}WO{sub 3}). The terminal phase shows an unusual transport property featuring slightly negative temperature-dependence in resistivity (dρ/dT<0) and a large Wilson ratio of R{sub W}=3.2. Such anomalous metallic behavior possibly arises from the low-dimensional electronic structure with a van Hove singularity at the Fermi level and/or from enhanced magnetic fluctuations by geometrical frustration of the tungsten sublattice. The asymmetric nature of the tetragonal tungsten bronze K{sub x}WO{sub 3}-K{sub 0.6-y}Ba{sub y}WO{sub 3} phase diagram implies that superconductivity for x≤0.45 originates from the lattice instability because of potassium deficiency. A cubic perovskite KWO{sub 3} phase was also identified as a line phase - in marked contrast to Na{sub x}WO{sub 3} and Li{sub x}WO{sub 3} with varying quantities of x (<1). This study presents a versatile method by which the solubility limit of tungsten bronze oxides can be extended. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. On the nature of phase transitions in the tetragonal tungsten bronze GdK{sub 2}Nb{sub 5}O{sub 15} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Gagou, Y.; Lukyanchuk, I.; El Marssi, M., E-mail: mimoun.elmarssi@u-picardie.fr [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cedex (France); Amira, Y. [Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cedex (France); Laboratoire de la Matière Condensée et Nanostructures, FSTG, Université Cadi Ayyad Marrakech, Maroc (Morocco); Mezzane, D. [Laboratoire de la Matière Condensée et Nanostructures, FSTG, Université Cadi Ayyad Marrakech, Maroc (Morocco); Courty, M.; Masquelier, C. [Laboratoire de Réactivité et Chimie des Solides, UMR 7314, Université de Picardie Jules Verne, Pôle Scientifique, 33 rue Saint-Leu, 80039 Amiens Cedex 1 (France); Yuzyuk, Yu. I. [Faculty of Physics, Southern Federal University, 5, Zorge Str. Rostov-on-Don 344090 (Russian Federation)

    2014-02-14

    Phase transitions in gadolinium potassium niobate GdK{sub 2}Nb{sub 5}O{sub 15} (GKN) ceramics have been investigated by x-ray diffraction, dielectric susceptibility, differential scanning calorimetry, and Raman scattering. The results of our complementary studies show that GKN exhibits two phase transitions at T{sub c1} = 238 °C and T{sub c2} = 375 °C attributed to the ferroelectric-antiferroelectric-paraelectric (FE-AFE-PE) phase transitions. According to the x-ray diffraction analysis, the FE and PE phases were refined in the polar P4bm and centrosymmetric P4/mbm space groups. For the intermediate phase, the structure is refined in the space group P4nc with doubling of the c unit cell parameter, which is compatible with an AFE phase. This result was confirmed by Raman spectroscopy since new low-frequency lines are activated in the AFE phase due to the Brillouin zone-folding effect, typical for the modulated phases. The presence of the AFE phase between the FE and PE phases and the complex nature of tetragonal tungsten bronze crystal structure can explain the large thermal hysteresis observed at the FE-AFE transition between heating and cooling cycle and the strong depression of the Curie-Weiss temperature T{sub 0}. The semi-phenomenological Ising-like model based on the obtained experimental data is proposed to account for the observed FE-AFE-PE transition sequence.

  4. Synthesis and single crystal X-ray structure of the tetragonal tungsten bronze Pb{sub 0.91}K{sub 1.72}Li{sub 1.46}Nb{sub 5}O{sub 15}

    Energy Technology Data Exchange (ETDEWEB)

    Capitelli, F. [Institute of Crystallography - CNR, Via Salaria Km 29.300, 00016 Monterotondo Rome (Italy); Rossi, M. [Earth Sciences Department, Federico II University, Via Mezzocannone 8, 80134 Naples (Italy); Elaatmani, M.; Zegzouti, A. [Laboratoire de Chimie du Solide Mineral, Faculte des Sciences Semlalia, Universite Cadi Ayyad, Marrakech (Morocco)

    2010-11-15

    Crystals of Pb{sub 0.91}K{sub 1.72}Li{sub 1.46}Nb{sub 5}O{sub 15}, belonging to tetragonal tungsten bronze materials, were grown by the slow cooling technique, and characterized by means of single crystal X-ray diffraction: the structure was solved in the P4bm tetragonal space group, with the following unit cell parameters: a = 12.548(5), c = 4.042(5)A, V = 636.4(9)A{sup 3}. The three-dimensional framework can be described as a layered structure down crystallographic axis c, with arrays of NbO{sub 6} octahedra, whose corner sharing makes up the formation of tunnels filled up by Li, Pb and K displaying complex cation-oxygen coordinations. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Análise cristalográfica da solução sólida com estrutura tipo Tungstênio Bronze de niobato de potássio e estrôncio dopado com ferro Crystallographic analysis of the solid solution of iron doped potassium strontium niobate with tetragonal tungsten bronze structure

    Directory of Open Access Journals (Sweden)

    Silvania Lanfredi

    2010-01-01

    Full Text Available Solid solution of iron doped potassium strontium niobate with KSr2(FeNb4O15-Δ stoichiometry was prepared by high efficiency ball milling method. Structural characterization was carried out by X-ray diffraction. Crystalline structure was analyzed by the Rietveld refinements using the FullProf software. The results showed a tetragonal system with the tetragonal tungsten bronze structure - TTB (a = 12.4631 (2 Å and c = 3.9322 (6 Å, V = 610.78 (2 ų. In this work, the sites occupancy by the K+, Sr2+ and Fe3+ cations on the TTB structure were determined. NbO6 polihedra distortion and its correlation with the theoretical polarization are discussed.

  6. A pseudo-tetragonal tungsten bronze superstructure: a combined solution of the crystal structure of K6.4(Nb,Ta)(36.3)O94 with advanced transmission electron microscopy and neutron diffraction.

    Science.gov (United States)

    Paria Sena, Robert; Babaryk, Artem A; Khainakov, Sergiy; Garcia-Granda, Santiago; Slobodyanik, Nikolay S; Van Tendeloo, Gustaaf; Abakumov, Artem M; Hadermann, Joke

    2016-01-21

    The crystal structure of the K6.4Nb28.2Ta8.1O94 pseudo-tetragonal tungsten bronze-type oxide was determined using a combination of X-ray powder diffraction, neutron diffraction and transmission electron microscopy techniques, including electron diffraction, high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), annular bright field STEM (ABF-STEM) and energy-dispersive X-ray compositional mapping (STEM-EDX). The compound crystallizes in the space group Pbam with unit cell parameters a = 37.468(9) Å, b = 12.493(3) Å, c = 3.95333(15) Å. The structure consists of corner sharing (Nb,Ta)O6 octahedra forming trigonal, tetragonal and pentagonal tunnels. All tetragonal tunnels are occupied by K(+) ions, while 1/3 of the pentagonal tunnels are preferentially occupied by Nb(5+)/Ta(5+) and 2/3 are occupied by K(+) in a regular pattern. A fractional substitution of K(+) in the pentagonal tunnels by Nb(5+)/Ta(5+) is suggested by the analysis of the HAADF-STEM images. In contrast to similar structures, such as K2Nb8O21, also parts of the trigonal tunnels are fractionally occupied by K(+) cations.

  7. Phase transitions and electrical characterizations of (K 0.5Na 0.5) 2x(Sr 0.6Ba 0.4) 5-xNb 10O 30 (KNSBN) ceramics with 'unfilled' and 'filled' tetragonal tungsten-bronze (TTB) crystal structure

    KAUST Repository

    Yao, Yingbang

    2012-12-01

    Alkali-doped strontium barium niobate (K 0.5Na 0.5) 2x(Sr 0.6Ba 0.4) 5-xNb 10O 30 (KNSBN) ceramics has been prepared by a conventional solid-state reaction method. The alkali-dopant concentration x has been varied from 0.24 to 1.15 so that the crystal structure was transformed from \\'unfilled\\' to \\'filled\\' tetragonal tungsten-bronze (TTB) structure. Apart from the change in the structural properties, the effects of the alkali-dopants on the phase transition as well as ferroelectric, piezoelectric and pyroelectric properties have also been investigated. Phase transitions have been studied in the temperature range of -200°C to 350°C. The origins of these phase transitions are discussed. The addition of the alkali-dopants enhances the ferroelectric, piezoelectric and pyroelectric properties of the KNSBN ceramics. Alkali-doping also favors abnormal grain growth and thus results in a porous microstructure, which might contribute to the enhancement of the pyroelectric performance. © 2012 Elsevier Ltd.

  8. Manipulation of polar order in the “empty” tetragonal tungsten bronzes: Ba{sub 4-x}Sr{sub x}Dy{sub 0.67}□{sub 1.33}Nb{sub 10}O{sub 30}, x = 0, 0.25, 0.5, 1, 2, 3

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, Jonathan; Morrison, Finlay D., E-mail: finlay.morrison@st-andrews.ac.uk [EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST (United Kingdom)

    2016-08-15

    A series of “empty” tetragonal tungsten bronze (TTB) ferroelectrics, Ba{sub 4-x}Sr{sub x}Dy{sub 0.67}□{sub 1.33}Nb{sub 10}O{sub 30} (x = 0, 0.25, 0.5, 1, 2, 3; □ = vacancy), is reported. With increasing x the unit cell contracts in both the ab plane and c-axis; x ≤ 1 compounds are normal ferroelectrics (FE) with decreasing T{sub C} as x increases, while x ≥ 2 are relaxor ferroelectrics (RFE) with associated frequency dependent permittivity peaks and with similar T{sub m} and T{sub f} (Vogel-Fulcher freezing temperatures) values. This observation is rationalised by differing cation occupancies: for x ≤ 1, Sr{sup 2+} principally occupies the A2-site (co-occupied by Ba{sup 2+} with the A1-site occupied by Dy{sup 3+} and vacancies); for x ≥ 2 significant Sr A1-site occupation leads to the observed RFE characteristics. This FE to RFE crossover is consistent with a previously proposed TTB crystal chemical framework where both a decrease in average A-site size and concurrent increase in A1-site tolerance factor (t{sub A1}) favour destabilization of long range polar order and relaxor behaviour. The effect of increasing t{sub A1} as a result of Sr occupancy at the A1 site is dominant in the compounds reported here.

  9. Bronze Age Acrobats

    DEFF Research Database (Denmark)

    Iversen, Rune

    2014-01-01

    A Danish eighteenth-century find of some bronze figurines tells the story of the practising of similar ritual performances across Bronze Age Europe from Egypt to Scandinavia. The Danish figurines, as well as Swedish rock carvings, show backwards-bending female acrobats doing backward handsprings...... of the immaterial, ritual and cosmological exchange that characterized the second and early firstmillennium BC.Beliefs and ritual practices went hand in hand with the adoption of a series of elite items and an aristocratic lifestyle, thereby creating a unique and fascinating European Bronze Age....

  10. Bronze rainbow hologram mirrors

    Science.gov (United States)

    Dawson, P.

    2006-02-01

    This project draws on holographic embossing techniques, ancient artistic conventions of bronze mirror design and modelling and casting processes to accomplish portraiture of reflection. Laser scanning, 3D computer graphics and holographic imaging are employed to enable a permanent 3D static holographic image to appear integrated with the real-time moving reflection of a viewer's face in a polished bronze disc. The disc and the figure which holds it (caryatid) are cast in bronze from a lost wax model, a technique which has been used for millennia to make personal mirrors. The Caryatid form of bronze mirror which went through many permutations in ancient Egyptian, Greece and Rome shows a plethora of expressive figure poses ranging from sleek nudes to highly embellished multifigure arrangements. The prototype of this series was made for Australian choreographer Graeme Murphy, Artistic Director of the Sydney Dance Company. Each subsequent mirror will be unique in figure and holographic imagery as arranged between artist and subject. Conceptually this project references both the modern experience of viewing mirrors retrieved from ancient tombs, which due to deterioration of the surface no longer reflect, and the functioning of Chinese Magic mirrors, which have the ability to project a predetermined image. Inspired by the metaphorical potential of these mirrors, which do not reflect the immediate reality of the viewer, this bronze hologram mirror series enables each viewer to reflect upon himself or herself observing simultaneously the holographic image and their own partially obliterated reflection.

  11. Bronze amulet from Sidak

    OpenAIRE

    Smagulov Erbulat A.

    2014-01-01

    A bronze amulet in the shape of a horseman found on the citadel of the Sidak fortified settlement site in Turkestan district, Southern Kazakhstan oblast is described in the article. Similar findings are met on the vast Eurasian area ranging from Mongolia to the Urals. The published item may be referred to a series of similar finds from the handicraft centers located in the Syr Darya river basin, such as Khujand, Kanka, and, lately, Sidak. Handicraft centers of Sogdiana are traditionally regar...

  12. Etruscan and Italic bronze statuettes

    NARCIS (Netherlands)

    Galestin, Marianne Caroline

    1987-01-01

    In Central Italy, small bronze statuettes were made in thousands in antiquity and also the number which still remains is considerable. This amount is in shrill contrast to that of the life-size bronzes which amply decorated Etruscan cities, as the written sources tell us; very few of these larger

  13. Bronze railing from Mediana

    Directory of Open Access Journals (Sweden)

    Vasić Miloje R.

    2003-01-01

    Full Text Available The hoard containing components of bronze railing was discovered in trench 7 during excavations at Mediana in 2000. Railing consists of cancelli and herms with busts of deities between them. Railing was constructed in such a way that it was possible to disassemble and reassemble it. Three cancelli one fragmented semicancellus cast together with herm and herms, one with bust of Aesculapius and other with bust of Luna. It could be concluded that railing consisted of two segments with passage between them. Male deities were represented on the left segment of the railing and female deities on the right segment. Detailed analysis revealed that Aesculapius as well as Luna bear strong mark of classical Greek and Hellenistic art, which experienced some kind of renaissance in the time of Constantine I. It is very probable that we can recognize the portrait of Faustina, Constantine’s wife in the portrait of Luna. According to the historical events the railing could have been produced before 325 AD when Constantine definitively accepted Christianity at Council of Nicaea. It is difficult to say where the railing had been produced. It had been most probably brought to Mediana during the stay of emperor Julian in Niš in 361. The sculptures found in one room of the villa with peristyle had probably been brought at the same time. The apse of triclinium of this villa had most likely been arranged as small shrine with bronze railing at its entrance. The railing was buried in 378 after battle of Adrianople and invasion of Goths in diocese Dacia.

  14. Mummification in Bronze Age Britain

    OpenAIRE

    Booth, T. J.; Chamberlain, A.T.; Pearson, M.P.

    2015-01-01

    Intentional mummification is a practice usually associated with early Egyptian or Peruvian societies, but new evidence suggests that it may also have been widespread in prehistoric Britain, and possibly in Europe more generally. Following the discovery of mummified Bronze Age skeletons at the site of Cladh Hallan in the Western Isles of Scotland, a method of analysis has been developed that can consistently identify previously mummified skeletons. The results demonstrate that Bronze Age popul...

  15. Decorative layers on tin bronzes

    OpenAIRE

    Z. Konopka; M. Nadolski; A. Zyska; M. Łągiewka

    2010-01-01

    Decorative layers are decisive for aesthetic value of castings, therefore significant demands are raised towards such layers, e.g. pleasant durable colour, gloss, and smoothness. The work discusses the influence of the type of mechanical working applied to the surfaces of CuSn10 tin bronze castings on the quality and durability of a decorative coating. The scope of the work has included designing and manufacturing of cast samples of tin bronze, mechanical working of the surfaces in order to p...

  16. Bronze amulet from Sidak

    Directory of Open Access Journals (Sweden)

    Smagulov Erbulat A.

    2014-03-01

    Full Text Available A bronze amulet in the shape of a horseman found on the citadel of the Sidak fortified settlement site in Turkestan district, Southern Kazakhstan oblast is described in the article. Similar findings are met on the vast Eurasian area ranging from Mongolia to the Urals. The published item may be referred to a series of similar finds from the handicraft centers located in the Syr Darya river basin, such as Khujand, Kanka, and, lately, Sidak. Handicraft centers of Sogdiana are traditionally regarded as places of their manufacture. However, no finds of the kind are mentioned at proper Sogdian towns (Penjikent, Paikend, Afrasyab, etc., which have been thoroughly studied. Hence, the author makes a conclusion that these amulets, as well as many other pieces of jewelry were manufactured in the 7th to 8th centuries AD at the handicraft centers of Chach, a state formation comprising the Middle Syr-Darya River oases at the time. This region was inhabited by the descendants of the ancient Kangju state inhabitants, who inherited cultural traditions of the past, including the myths about the hero-horseman.

  17. Decorative layers on tin bronzes

    Directory of Open Access Journals (Sweden)

    Z. Konopka

    2010-10-01

    Full Text Available Decorative layers are decisive for aesthetic value of castings, therefore significant demands are raised towards such layers, e.g. pleasant durable colour, gloss, and smoothness. The work discusses the influence of the type of mechanical working applied to the surfaces of CuSn10 tin bronze castings on the quality and durability of a decorative coating. The scope of the work has included designing and manufacturing of cast samples of tin bronze, mechanical working of the surfaces in order to prepare them for applying coating layers,generating decorative layers as a result of chemical reactions, and the quality assessment and comparison of the obtained coating. Theassessment of thickness and continuity of the obtained decorative layers based on metallographic examinations has been presented.

  18. A bronze amulet from Sidak

    OpenAIRE

    Smagulov Erbulat A.

    2014-01-01

    A bronze amulet in the shape of a horseman found on the citadel of the Sidak fortified settlement site in Turkestan district, Southern Kazakhstan oblast is described in the article. Similar findings are met on the vast Eurasian area ranging from Mongolia to the Urals. The published item may be referred to a series of similar finds from the handicraft centers located in the Syr Darya river basin, such as Khujand, Kanka, and, lately, Sidak. Handicraft centers of Sogdiana are traditionally regar...

  19. 75 FR 14257 - Pricing for Bronze Medals

    Science.gov (United States)

    2010-03-24

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE TREASURY United States Mint Pricing for Bronze Medals AGENCY: United States Mint, Department of the Treasury. ACTION: Notice. SUMMARY: The United States Mint is announcing the price of the 1\\5/16\\- inch bronze...

  20. The Bronze Age Smith as Individual

    DEFF Research Database (Denmark)

    Nørgaard, Heide Wrobel

    During 1550-1100 BC magnificent decorated bronze objects appear in grave and hoard finds in Northwest Europe. While investigating similarities in the decorative elements of bronze objects belonging to the female gender, it is possible to find traces of the production process. These distinctive fe...

  1. Behaviour of millscale reinforced Aluminium Bronze composite ...

    African Journals Online (AJOL)

    Despite the desirable characteristics exhibited by most aluminium bronze, the deficient responses in certain critical applications have necessitated improvement in the mechanical properties. The microstructural and mechanical properties of cast aluminium bronze reinforced with iron millscale particles were investigated in ...

  2. New Research on Bronze Age Textile Production

    DEFF Research Database (Denmark)

    Andersson, Eva Birgitta; Mårtensson, Linda; Nosch, Marie-Louise Bech

    2008-01-01

    presentation of the results from the systematic tests with Bronze Age textile tools. results concerning mesurements of lenght and time consumed.......presentation of the results from the systematic tests with Bronze Age textile tools. results concerning mesurements of lenght and time consumed....

  3. Population genomics of Bronze Age Eurasia.

    Science.gov (United States)

    Allentoft, Morten E; Sikora, Martin; Sjögren, Karl-Göran; Rasmussen, Simon; Rasmussen, Morten; Stenderup, Jesper; Damgaard, Peter B; Schroeder, Hannes; Ahlström, Torbjörn; Vinner, Lasse; Malaspinas, Anna-Sapfo; Margaryan, Ashot; Higham, Tom; Chivall, David; Lynnerup, Niels; Harvig, Lise; Baron, Justyna; Della Casa, Philippe; Dąbrowski, Paweł; Duffy, Paul R; Ebel, Alexander V; Epimakhov, Andrey; Frei, Karin; Furmanek, Mirosław; Gralak, Tomasz; Gromov, Andrey; Gronkiewicz, Stanisław; Grupe, Gisela; Hajdu, Tamás; Jarysz, Radosław; Khartanovich, Valeri; Khokhlov, Alexandr; Kiss, Viktória; Kolář, Jan; Kriiska, Aivar; Lasak, Irena; Longhi, Cristina; McGlynn, George; Merkevicius, Algimantas; Merkyte, Inga; Metspalu, Mait; Mkrtchyan, Ruzan; Moiseyev, Vyacheslav; Paja, László; Pálfi, György; Pokutta, Dalia; Pospieszny, Łukasz; Price, T Douglas; Saag, Lehti; Sablin, Mikhail; Shishlina, Natalia; Smrčka, Václav; Soenov, Vasilii I; Szeverényi, Vajk; Tóth, Gusztáv; Trifanova, Synaru V; Varul, Liivi; Vicze, Magdolna; Yepiskoposyan, Levon; Zhitenev, Vladislav; Orlando, Ludovic; Sicheritz-Pontén, Thomas; Brunak, Søren; Nielsen, Rasmus; Kristiansen, Kristian; Willerslev, Eske

    2015-06-11

    The Bronze Age of Eurasia (around 3000-1000 BC) was a period of major cultural changes. However, there is debate about whether these changes resulted from the circulation of ideas or from human migrations, potentially also facilitating the spread of languages and certain phenotypic traits. We investigated this by using new, improved methods to sequence low-coverage genomes from 101 ancient humans from across Eurasia. We show that the Bronze Age was a highly dynamic period involving large-scale population migrations and replacements, responsible for shaping major parts of present-day demographic structure in both Europe and Asia. Our findings are consistent with the hypothesized spread of Indo-European languages during the Early Bronze Age. We also demonstrate that light skin pigmentation in Europeans was already present at high frequency in the Bronze Age, but not lactose tolerance, indicating a more recent onset of positive selection on lactose tolerance than previously thought.

  4. Population genomics of Bronze Age Eurasia

    OpenAIRE

    Allentoft Morten E.; Sikora Martin; Sjögren Karl-Göran; Rasmussen Simon; Rasmussen Morten; Stenderup Jesper; Damgaard Peter B.; Schroeder Hannes; Ahlström Torbjörn; Vinner Lasse; Malaspinas Anna-Sapfo; Margaryan Ashot; Higham Tom; Chivall David; Lynnerup Niels

    2015-01-01

    The Bronze Age of Eurasia (around 3000–1000 BC) was a period of major cultural changes. However there is debate about whether these changes resulted from the circulation of ideas or from human migrations potentially also facilitating the spread of languages and certain phenotypic traits. We investigated this by using new improved methods to sequence low coverage genomes from 101 ancient humans from across Eurasia. We show that the Bronze Age was a highly dynamic period involving large scale p...

  5. Asymmetric behaviour of Jc(ɛ) in Nb3Sn wires and correlation with the stress induced elastic tetragonal distortion

    Science.gov (United States)

    Flükiger, R.; Uglietti, D.; Abächerli, V.; Seeber, B.

    2005-12-01

    The effect of uniaxial strain on the critical current of 0.8 m long Nb3Sn wires up to 21 T is studied by the modified Walters spring (WASP). For Nb3Sn wires, prepared by both the bronze route and the internal Sn diffusion process, the critical current density as a function of the uniaxial strain ɛ is found to exhibit an asymmetric behaviour on both sides of the strain ɛm, where Jc reaches its maximum. Revisiting earlier x-ray and neutron diffraction measurements on bronze route processed wires between 10 and 600 K, it is shown that the asymmetric behaviour of Jc(ɛ) on both sides of the strain value ɛm is connected to individual variations of the stress-induced tetragonal lattice parameters a and c. The present measurements of Jc versus strain for Nb3Sn wires show stronger strain dependence for wires prepared by the internal Sn diffusion method with respect to those obtained by the bronze route. The reasons for this difference are attributed to the individual details of the filament configuration in both types of wire, for example the different Sn distributions inside the filaments and the very different filament sizes, 4 and 80 µm, respectively.

  6. Bronze-mean hexagonal quasicrystal

    Science.gov (United States)

    Dotera, Tomonari; Bekku, Shinichi; Ziherl, Primož

    2017-10-01

    The most striking feature of conventional quasicrystals is their non-traditional symmetry characterized by icosahedral, dodecagonal, decagonal or octagonal axes. The symmetry and the aperiodicity of these materials stem from an irrational ratio of two or more length scales controlling their structure, the best-known examples being the Penrose and the Ammann-Beenker tiling as two-dimensional models related to the golden and the silver mean, respectively. Surprisingly, no other metallic-mean tilings have been discovered so far. Here we propose a self-similar bronze-mean hexagonal pattern, which may be viewed as a projection of a higher-dimensional periodic lattice with a Koch-like snowflake projection window. We use numerical simulations to demonstrate that a disordered variant of this quasicrystal can be materialized in soft polymeric colloidal particles with a core-shell architecture. Moreover, by varying the geometry of the pattern we generate a continuous sequence of structures, which provide an alternative interpretation of quasicrystalline approximants observed in several metal-silicon alloys.

  7. A bronze amulet from Sidak

    Directory of Open Access Journals (Sweden)

    Smagulov Erbulat A.

    2014-03-01

    Full Text Available A bronze amulet in the shape of a horseman found on the citadel of the Sidak fortified settlement site in Turkestan district, Southern Kazakhstan oblast is described in the article. Similar findings are met on the vast Eurasian area ranging from Mongolia to the Urals. The published item may be referred to a series of similar finds from the handicraft centers located in the Syr Darya river basin, such as Khujand, Kanka, and, lately, Sidak. Handicraft centers of Sogdiana are traditionally regarded as places of their manufacture. However, no finds of the kind are mentioned at proper Sogdian towns (Penjikent, Paikend, Afrasyab, etc., which have been thoroughly studied. Hence, the author makes a conclusion that these amulets, as well as many other pieces of jewelry were manufactured in the 7th to 8th centuries AD at the handicraft centers of Chach, a state formation comprising the Middle Syr-Darya River oases at the time. This region was inhabited by the descendants of the ancient Kangju state inhabitants, who inherited cultural traditions of the past, including the myths about the hero-horseman.

  8. 77 FR 14600 - Pricing for 2012 Kennedy Half-Dollar Bags and Rolls, Bronze Medals, the First Spouse Bronze Medal...

    Science.gov (United States)

    2012-03-12

    ... United States Mint Pricing for 2012 Kennedy Half-Dollar Bags and Rolls, Bronze Medals, the First Spouse.... SUMMARY: The United States Mint is announcing 2012 pricing for Kennedy Half-Dollar bags and rolls, bronze medals, the First Spouse Bronze Medal Set and the Birth Set. Product Retail price Kennedy Half-Dollar...

  9. Bismuth bronze from machu picchu, peru.

    Science.gov (United States)

    Gordon, R B; Rutledge, J W

    1984-02-10

    The decorative bronze handle of a tumi excavated at the Inca city of Machu Picchu, Peru, contains 18 percent bismuth and appears to be the first known example of the use of bismuth with tin to make bronze. The alloy is not embrittled by the bismuth because the bismuth-rich constituent does not penetrate the grain boundaries of the matrix phase. The use of bismuth facilitates the duplex casting process by which the tumi was made and forms an alloy of unusual color.

  10. Glass ceramic toughened with tetragonal zirconia

    Science.gov (United States)

    Keefer, Keith D.; Michalske, Terry A.

    1986-01-01

    A phase transformation-toughened glass ceramic and a process for making it are disclosed. A mixture of particulate network-forming oxide, network-modifying oxide, and zirconium oxide is heated to yield a homogeneous melt, and this melt is then heat-treated to precipitate an appreciable quantity of tetragonal zirconia, which is retained at ambient temperature to form a phase transformation-toughened glass ceramic. Nucleating agents and stabilizing agents may be added to the mixture to facilitate processing and improve the ceramic's properties. Preferably, the mixture is first melted at a temperature from 1200.degree. to 1700.degree. C. and is then heat-treated at a temperature within the range of 800.degree. to 1200.degree. C. in order to precipitate tetragonal ZrO.sub.2. The composition, as well as the length and temperature of the heat-treatment, must be carefully controlled to prevent solution of the precipitated tetragonal zirconia and subsequent conversion to the monoclinic phase.

  11. Population genomics of Bronze Age Eurasia

    DEFF Research Database (Denmark)

    Allentoft, Morten E.; Sikora, Martin; Sjögren, Karl-Göran

    2015-01-01

    investigated this by using new, improved methods to sequence low-coverage genomes from 101 ancient humans from across Eurasia. We show that the Bronze Age was a highly dynamic period involving large-scale population migrations and replacements, responsible for shaping major parts of present-day demographic...

  12. Stabilization of metastable tetragonal zirconia nanocrystallites by surface modification

    DEFF Research Database (Denmark)

    Nielsen, Mette Skovgaard; Almdal, Kristoffer; Lelieveld, A. van

    2011-01-01

    was tested by prolonged boiling in water. The samples were analyzed with X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Changes in the monoclinic volume fraction in the samples were calculated. A number of surfactants were screened for their ability to stabilize the tetragonal phase upon......-methacryloxypropyl trimethoxy silane were even capable of preventing phase transformation during boiling for 48 h in water.......Metastable tetragonal zirconia nanocrystallites were studied in humid air and in water at room temperature (RT). A stabilizing effect of different surfactants on the tetragonal phase was observed. Furthermore, the phase stability of silanized metastable tetragonal zirconia nanocrystallites...

  13. Growth of Tungsten Bronze Family Crystals

    Science.gov (United States)

    1989-03-01

    Keesrer. Mater Res BuL 15 t]s , 13(5the discussions on this. research b\\ Profesor .f J[19] R R Neurgaonkar W.K Cot.s and J R (Oi,’e- I-errocl. s otncs 35...L" tic . 22 𔃻 als, demonstrated’ the growth of excellent qual;tv bronze !N’BO.0. substrates using thie LPL and sputtering techniques. C.Car. to gt

  14. Uncommon corrosion phenomena of archaeological bronze alloys

    Science.gov (United States)

    Ingo, G. M.; de Caro, T.; Riccucci, C.; Khosroff, S.

    2006-06-01

    In the framework of the EFESTUS project (funded by the European Commission, contract No. ICA3-CT-2002-10030) the corrosion products of a large number of archaeological bronze artefacts are investigated by means of the combined use of scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD) and optical microscopy (OM) and tentative correlation of their nature with the chemical composition of the artefacts and the burial context is proposed. The results provide good insight into the corrosion layers and evidence in some bronze Roman coins and artefacts; the occurrence of uncommon corrosion phenomena that give rise to the formation of a yellowish-green complex chlorine-phosphate of lead (pyromorphite, (PbCl)Pb4(PO4)3) and of a gold-like thick layer of an iron and copper sulphide (chalcopyrite, CuFeS2). The micro-chemical and micro-structural results show that the coins were buried in a soil enriched in phosphorus for the accidental presence of a large amount of decomposing fragments of bones or in an anaerobic and humus rich soil where the chalcopyrite layer has been produced via the interaction between the iron of the soil, the copper of the coin and the sulphur produced by the decomposition of organic matter in an almost oxygen free environment. Finally, some unusual periodic corrosion phenomena occurring in high tin bronze mirrors found at Zama (Tunisia) are described.

  15. Making yttria-stabilized tetragonal zirconia translucent

    Science.gov (United States)

    Zhang, Yu

    2014-01-01

    Objective The aim of this study was to provide a design guideline for developing tetragonal yttria-stabilized zirconia with improved translucency. Methods The translucency, the in-line transmission in particular, of 3 mol.% yttria-stabilized tetragonal zirconia (3Y-TZP) has been examined using the Rayleigh scattering model. The theory predicts that the in-line transmission of 3Y-TZP can be related to its thickness with grain size and birefringence the governing parameters. To achieve a threshold value of translucency, the critical grain size of 3Y-TZP was predicted for various thicknesses (0.3 – 2.0 mm). The threshold value was defined by a measured average in-line transmission value of a suite of dental porcelains with a common thickness of 1 mm. Our theoretical predictions were calibrated with one of the very few experimental data available in the literature. Results For a dense, high-purity zirconia, its in-line transmission increased with decreasing grain size and thickness. To achieve a translucency similar to that of dental porcelains, a nanocyrstalline 3Y-TZP structure was necessitated, due primarily to its large birefringence and high refractive index. Such a grain size dependence became more pronounced as the 3Y-TZP thickness increased. For example, at a thickness of 1.3 mm, the mean grain size of a translucent 3Y-TZP should be 82 nm. At 1.5 mm and 2 mm thicknesses, the mean grain size needed to be 77 nm and 70 nm, respectively. Significance A promising future for zirconia restorations, with combined translucency and mechanical properties, can be realized by reducing its grain size. PMID:25193781

  16. Examination of Ife Bronze Casting Culture and Its Decline in ...

    African Journals Online (AJOL)

    Ile-Ife, the Yoruba ancient city is known for its vibrant cultural environment. This city of ancient civilization and one of the home for bronze casting in the Western region of Nigeria have made significant contributions to the world of culture through its great artistic traditions in terracotta, bead making, bronze and brass casting ...

  17. The thermal analysis and derivative bronzes cast to plaster moulds

    Directory of Open Access Journals (Sweden)

    B. Pisarek

    2009-07-01

    Full Text Available It plaster moulds gets casted the alloys of following metals: Al, Cu, Ag, Au in precise and artistic founding. The investigation of the crys-tallization of bronzes in hot plaster moulds the method of the thermal analysis and derivative (TDA was not realized out so far. Probe TDAg and tripod enabling the execution of measurements on inductive casting machine INDUTHERM-VC 500D were designed for this technology especially. It was confirmed that one the method TDA can identify the crystallization process of the bronze in hot plaster moulds. The investigations of the superficial distribution of the concentration of elements in the microstructure of the studied grades of the bronze on X-ray microanalizer were conducted. It results that they be subject to in bronze CuSn10-C (B10 and the CuSn5Zn5Pb5-C (B555 of strong microsegregation from conducted investigations: Pb, Sn and Sb. The single separates of intermetallic phase κ was identified in the bronze B10 rich first of all in Zn, Sn, Sb and Fe, and two intermetallic phase, one rich were identified in the bronze B555 first of all in Zn, Sb, (Nor, Fe and second rich in Sn, Sb, (Nor, Fe. The most homogeneous microstructure from the bronze CuAl10Fe5Ni5-C (BA1055 is characterizes among the studied grades of the bronze in the cast state.

  18. Thermal and Electrical Conductivity Measurements of CDA 510 Phosphor Bronze

    Science.gov (United States)

    Tuttle, James E.; Canavan, Edgar; DiPirro, Michael

    2009-01-01

    Many cryogenic systems use electrical cables containing phosphor bronze wire. While phosphor bronze's electrical and thermal conductivity values have been published, there is significant variation among different phosphor bronze formulations. The James Webb Space Telescope (JWST) will use several phosphor bronze wire harnesses containing a specific formulation (CDA 510, annealed temper). The heat conducted into the JWST instrument stage is dominated by these harnesses, and approximately half of the harness conductance is due to the phosphor bronze wires. Since the JWST radiators are expected to just keep the instruments at their operating temperature with limited cooling margin, it is important to know the thermal conductivity of the actual alloy being used. We describe an experiment which measured the electrical and thermal conductivity of this material between 4 and 295 Kelvin.

  19. Electro-optical properties of tetragonal KNbO3

    Indian Academy of Sciences (India)

    . On a structural point of view, the NLO properties of KNbO3 were theoretically investigated [4]. Another study [5], based on a microscopic model, investigated the role of polarizability in the EO properties of tetragonal phase. Those calculations.

  20. Modeling Tetragonal Lysozyme Crystal Growth Rates

    Science.gov (United States)

    Gorti, Sridhar; Forsythe, Elizabeth L.; Pusey, Marc L.

    2003-01-01

    Tetragonal lysozyme 110 face crystal growth rates, measured over 5 orders of magnitude in range, can be described using a model where growth occurs by 2D nucleation on the crystal surface for solution supersaturations of c/c(sub eq) less than or equal to 7 +/- 2. Based upon the model, the step energy per unit length, beta was estimated to be approx. 5.3 +/- 0.4 x 10(exp -7) erg/mol-cm, which for a step height of 56 A corresponds to barrier of approx. 7 +/- 1 k(sub B)T at 300 K. For supersaturations of c/c(sub eq) > 8, the model emphasizing crystal growth by 2D nucleation not only could not predict, but also consistently overestimated, the highest observable crystal growth rates. Kinetic roughening is hypothesized to occur at a cross-over supersaturation of c/c(sub eq) > 8, where crystal growth is postulated to occur by a different process such as adsorption. Under this assumption, all growth rate data indicated that a kinetic roughening transition and subsequent crystal growth by adsorption for all solution conditions, varying in buffer pH, temperature and precipitant concentration, occurs for c/c(sub eq)(T, pH, NaCl) in the range between 5 and 10, with an energy barrier for adsorption estimated to be approx. 20 k(sub B)T at 300 K. Based upon these and other estimates, we determined the size of the critical surface nucleate, at the crossover supersaturation and higher concentrations, to range from 4 to 10 molecules.

  1. Russian meteorite Bronze Age (rock record)

    CERN Document Server

    Vodolazhskaya, Larisa

    2013-01-01

    This paper presents the results of a study of petroglyphs found in the quartzite grotto near the Skelnovsky small village in the Northern Black Sea in the South of Russia. The aim of the study was the analysis and interpretation of the Early Bronze Age petroglyphs using archaeoastronomical methods. The article presents a comparative analysis of Skelnovsky grotto ancient images and contemporary eyewitness accounts of the Sikhote-Alin meteorite fall and meteorite shower. Some petroglyphs were interpreted by us using ethnographic and folklore material. In this study, the magnetic declination for the geographical coordinates Skelnovsky farm was calculated, and the projection of the whole picture Skelnovskih petroglyphs on the topographical map of the area was built. The proposed location of the meteorite fall was determined with this projection. It is confirmed by satellite pictures, on which are the distinguishable terrain features, typical for the meteorite fall, are visible including the possible impact crater...

  2. Bronze Age stone worlds of Bodmin Moor: excavating Leskernick

    Directory of Open Access Journals (Sweden)

    Sue Hamilton

    1999-11-01

    Full Text Available Most archaeological work on the British Bronze Age has been undertaken in Wessex. Here a team fr om UCL' s Institute of Archaeology and Department of Anthropology describe their investigation of a very different Bronze Age landscape on Bodmin Moor in Cornwall. Their project, at the site of Leskernick, is innovative in its methodology and in how it is presented to the public.

  3. Deformability of niobium and tin bronze during compression

    Science.gov (United States)

    Nikulin, S. A.; Rozhnov, A. B.; Aliev, R. M.; Rogachev, S. O.; Khatkevich, V. M.; Abdyukhanov, I. M.; Dergunova, E. A.; Traktirnikova, N. V.

    2015-10-01

    The deformability of Cu-14.5 wt % Sn-0.25 wt % Ti bronze and pure niobium (99.84%) is studied during compression tests. It is found that an increase in the strain rate or a decrease in the test temperature can improve the strength characteristics of both materials. The strength properties of bronze are more sensitive to a change in the temperature-rate deformation conditions.

  4. Pressure induced phase transitions in ceramic compounds containing tetragonal zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Sparks, R.G.; Pfeiffer, G.; Paesler, M.A.

    1988-12-01

    Stabilized tetragonal zirconia compounds exhibit a transformation toughening process in which stress applied to the material induces a crystallographic phase transition. The phase transition is accompanied by a volume expansion in the stressed region thereby dissipating stress and increasing the fracture strength of the material. The hydrostatic component of the stress required to induce the phase transition can be investigated by the use of a high pressure technique in combination with Micro-Raman spectroscopy. The intensity of Raman lines characteristic for the crystallographic phases can be used to calculate the amount of material that has undergone the transition as a function of pressure. It was found that pressures on the order of 2-5 kBar were sufficient to produce an almost complete transition from the original tetragonal to the less dense monoclinic phase; while a further increase in pressure caused a gradual reversal of the transition back to the original tetragonal structure.

  5. Tetragonal and cubic zirconia multilayered ceramic constructs created by EPD.

    Science.gov (United States)

    Mochales, Carolina; Frank, Stefan; Zehbe, Rolf; Traykova, Tania; Fleckenstein, Christine; Maerten, Anke; Fleck, Claudia; Mueller, Wolf-Dieter

    2013-02-14

    The interest in electrophoretic deposition (EPD) for nanomaterials and ceramics production has widely increased due to the versatility of this technique to effectively combine different materials in unique shapes and structures. We successfully established an EPD layering process with submicrometer sized powders of Y-TZP with different mol percentages of yttrium oxide (3 and 8%) and produced multilayers of alternating tetragonal and cubic phases with a clearly defined interface. The rationale behind the design of these multilayer constructs was to optimize the properties of the final ceramic by combining the high mechanical toughness of the tetragonal phase of zirconia together with the high ionic conductivity of its cubic phase. In this work, a preliminary study of the mechanical properties of these constructs proved the good mechanical integrity of the multilayered constructs obtained as well as crack deflection in the interface between tetragonal and cubic zirconia layers.

  6. Antiferromagnetic structure in tetragonal CuMnAs thin films

    Science.gov (United States)

    Wadley, P.; Hills, V.; Shahedkhah, M. R.; Edmonds, K. W.; Campion, R. P.; Novák, V.; Ouladdiaf, B.; Khalyavin, D.; Langridge, S.; Saidl, V.; Nemec, P.; Rushforth, A. W.; Gallagher, B. L.; Dhesi, S. S.; Maccherozzi, F.; Železný, J.; Jungwirth, T.

    2015-11-01

    Tetragonal CuMnAs is an antiferromagnetic material with favourable properties for applications in spintronics. Using a combination of neutron diffraction and x-ray magnetic linear dichroism, we determine the spin axis and magnetic structure in tetragonal CuMnAs, and reveal the presence of an interfacial uniaxial magnetic anisotropy. From the temperature-dependence of the neutron diffraction intensities, the Néel temperature is shown to be (480 ± 5) K. Ab initio calculations indicate a weak anisotropy in the (ab) plane for bulk crystals, with a large anisotropy energy barrier between in-plane and perpendicular-to-plane directions.

  7. Setup of Galvanic Sensors for the Monitoring of Gilded Bronzes

    Directory of Open Access Journals (Sweden)

    Sara Goidanich

    2014-04-01

    Full Text Available Traditional electrochemical techniques, such as linear polarization resistance (Rp, and electrochemical impedance spectroscopy (EIS, cannot be applied to gilded bronzes, as it may not be possible to interpret the results obtained due to the bimetallic nature of the studied material. The measurement of the macrocouple current generated by the gold/bronze galvanic couple can be used as an indicator of degradation processes. Nevertheless, this measurement cannot be performed directly on the original artifacts due to the systematic presence of short-circuits between the two metals. In the present work the use of galvanic sensors is proposed as a possible solution for the monitoring of gilded bronze artefacts. The sensors have been designed to simulate real gilded bronze surfaces in terms of composition and stratigraphy and have proved to be a reliable diagnostic tool for the in situ monitoring of the rates of deterioration of gilded bronze surfaces and to test new conservation treatments. Their set-up and application is reported and their performances discussed.

  8. Electro-optical properties of tetragonal KNbO3

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 68; Issue 6 ... Linear electro-optical tensor coefficients and optical susceptibility of tetragonal KNbO3 are calculated using a formalism based on bond charge theory. ... Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India ...

  9. Effect of Heat Treatment on Microstructural Changes in Aluminium Bronze

    Directory of Open Access Journals (Sweden)

    Hájek J.

    2016-09-01

    Full Text Available This paper attempts to summarise the microstructural changes which take place in aluminium bronzes during heat treatment. Another objective of this study was to map the potential of a certain type of aluminium bronzes for undergoing martensitic transformation. The methods, which were chosen for assessing the results of heat treatment with regard to their availability, included measurement of hardness and observation of microstructure using light and scanning electron microscopy, Additional tools for evaluation of microstructure comprised measurement of microhardness and chemical analysis by EDS. An important part of the experiment is observation of microstructural changes in the Jominy bar during the end-quench test. Upon completing experiments of this kind, one can define the heat treatment conditions necessary for obtaining optimum properties. In addition, the paper presents important findings on how to improve the corrosion resistance of aluminium bronzes by special heat treatment sequences.

  10. Fabrication of a Bronze Age Sword using Ancient Techniques

    Science.gov (United States)

    Sapiro, David; Webler, Bryan

    2016-12-01

    A khopesh was cast and forged for the TMS 2016 Bladesmithing Symposium. The khopesh was the first sword style, originating during the Bronze Age in the Near East. The manufacturing process used in this study closely followed Bronze Age techniques to determine the plausibility of open mold casting coupled with cold work and annealing cycles. Forging and annealing cycles substantially increased blade strength and diminished intergranular δ-phase inclusions. While a functional blade was not completed due to casting defects, the process gives valuable insight into the effort required to fabricate a khopesh during the Bronze Age. Forging and annealing cycles following casting were necessary to produce the mechanical properties desired in a sword.

  11. Archaeological investigations of the Bronze Age village of Bagnara di Romagna (RA

    Directory of Open Access Journals (Sweden)

    Maurizio Cattani

    2014-12-01

    Full Text Available This paper summarizes the results of researches carried out in the area next to the modern village of Bagnara di Romagna (RA, where several evidences related to a Bronze Age settlement have been collected. Recently test trenches and surface collections allowed to retrieve bronze and ceramics dating from the Middle Bronze Age (phase BM2 to the Recent Bronze Age (phase BR2. The analysis of landscape and the palaeoenvironmental reconstruction complete the outline of the region of Imola, Faenza and Lugo during the Bronze Age where are well known the ancient settlements of Solarolo, via Ordiere, Monte Castellaccio end S. Giuliano di Toscanella.

  12. Topological crystalline antiferromagnetic state in tetragonal FeS

    Science.gov (United States)

    Hao, Ningning; Zheng, Fawei; Zhang, Ping; Shen, Shun-Qing

    2017-10-01

    Integration between magnetism and topology is an exotic phenomenon in condensed-matter physics. Here, we propose an exotic phase named topological crystalline antiferromagnetic state, in which antiferromagnetism intrinsically integrates with nontrivial topology, and we suggest such a state can be realized in tetragonal FeS. A combination of first-principles calculations and symmetry analyses shows that the topological crystalline antiferromagnetic state arises from band reconstruction induced by pair checkerboard antiferromagnetic order together with band-gap opening induced by intrinsic spin-orbit coupling in tetragonal FeS. The topological crystalline antiferromagnetic state is protected by the product of fractional translation symmetry, mirror symmetry, and time-reversal symmetry, and presents some unique features. In contrast to strong topological insulators, the topological robustness is surface dependent. These findings indicate that nontrivial topological states could emerge in pure antiferromagnetic materials, which sheds new light on potential applications of topological properties in fast-developing antiferromagnetic spintronics.

  13. Chemically ordered face-centred tetragonal Fe–Pt nanoparticles ...

    Indian Academy of Sciences (India)

    2012-02-21

    Feb 21, 2012 ... Abstract. Chemically ordered face-centred tetragonal (fct) Fe–Pt alloy nanoparticles (NPs) embedded SiO2 films were synthesized on glass substrate by in situ hybrid sol–gel approach followed by heating at 450–900 ◦C in air and reducing (10% H2–90% Ar) atmospheres. Heat treatment of Fe/Pt co-doped ...

  14. Effect of additives on densification and deformation of tetragonal zirconia

    NARCIS (Netherlands)

    Boutz, M.M.R.; Boutz, M.M.R.; Winnubst, Aloysius J.A.; Hartgers, F.; Burggraaf, A.J.; Burggraaf, Anthonie

    1994-01-01

    The effect of additives (Bi2O3, Fe2O3) on densification and creep rates of tetragonal ZrO2-Y2O3 has been investigated. In Bi2O3-doped Y-TZP, a reactive liquid forms at temperatures above 800–900DaggerC, which leads to a strong enhancement of densification for concentrations of 1–2 mol % Bi2O3.

  15. Modeling the Mechanical Response of Tetragonal Lysozyme Crystals

    OpenAIRE

    Zamiri, Amir; De, Suvranu

    2010-01-01

    In this paper we investigate the mechanical response of tetragonal lysozyme crystals based on existing experimental data and a continuum-based crystal plasticity model. Compression analyses along different crystallographic directions reveal that the mechanical response of lysozyme crystals is highly anisotropic and orientation dependent. While the response is purely elastic along the [110] direction, it is elasto-plastic along the [100] and [2̄ 12] directions. The yield stress and critical re...

  16. Community Geothermal Technology Program: Silica bronze project. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bianchini, H.

    1989-10-01

    Objective was to incorporate waste silica from the HGP-A geothermal well in Pohoiki with other refractory materials for investment casting of bronze sculpture. The best composition for casting is about 50% silica, 25% red cinders, and 25% brick dust; remaining ingredient is a binder, such as plaster and water.

  17. Alarm calls of Bronze Mannikins communicate predator size to ...

    African Journals Online (AJOL)

    These groups were exposed to latex terrestrial snakes and mounted aerial raptors, and their alarm calls and predator response behaviours recorded. The Bronze Mannikins were able to discriminate between predators of different sizes, and increased their calling rate and decreased the end frequency of the alarm call in ...

  18. Aromatic quinoxaline as corrosion inhibitor for bronze in aqueous ...

    Indian Academy of Sciences (India)

    Administrator

    Keywords. Bronze; inhibitors; quinoxalin compounds; chloride solution; electrochemical studies. 1. Introduction. Heterocyclic organic compounds containing nitrogen, sulphur or oxygen atoms are often used to protect copper and copper alloy metals from corrosion. Among them, azoles compounds like triazoles, imidazoles ...

  19. Corrosion behavior of leaded-bronze alloys in sea water

    Energy Technology Data Exchange (ETDEWEB)

    Zohdy, K.M., E-mail: khalzohdy@yahoo.com [Higher Technological Institute, 10" t" h of Ramadan City (Egypt); Sadawy, M.M. [Mining and Petroleum Engineering Department, Al-Azhar University, Nasr City, Cairo 11371 (Egypt); Ghanem, M. [Industrial Education, Suez University (Egypt)

    2014-10-15

    The corrosion behavior of leaded-bronze alloys (Cu–5Sn–5Zn–5Pb, Cu–8Sn–8Zn–8Pb and Cu–10Sn–10Zn–10Pb) in sea water was investigated using weight loss method, open-circuit potential measurements (OCP), polarization techniques and electrochemical impedance spectroscopy (EIS). The nature and morphology of the corrosion products were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the corrosion resistance decreases with decreasing copper content. The XRD indicated that the composition of patina depends on the concentration of Cu, Sn, Zn and Pb in each alloy. - Highlights: • The corrosion potential of leaded bronze shifts to more noble potential. • The corrosion resistance increases with increasing amount of copper content in leaded bronze alloys. • The patina formed on Cu–5Sn–5Zn–5Pb is more uniform and protective than other alloys. • The composition of patina formed on leaded bronze depends on the concentration of Cu, Sn, Zn and Pb in the alloy.

  20. Foraging behaviour in tadpoles of the bronze frog Rana temporalis ...

    Indian Academy of Sciences (India)

    The ability of bronze frog Rana temporalis tadpoles (pure or mixed parental lines) to assess the profitability of food habitats and distribute themselves accordingly was tested experimentally using a rectangular choice tank with a non-continuous input design. Food (boiled spinach) was placed at two opposite ends of the ...

  1. Electrodeposited nanocrystalline bronze alloys as replacement for Ni

    NARCIS (Netherlands)

    Hovestad, A.; Tacken, R.A.; Mannetje, H.H.'t

    2008-01-01

    Nanocrystalline white-bronze, CuSn, electroplating was investigated as alternative to Ni plating as undercoat for noble metals in jewellery applications. A strongly acidic plating bath was developed with an organic additive to suppress hydrogen evolution and obtain bright coatings. Polarization

  2. Tribological study of a bronze obtained by Sintering proceeds ...

    African Journals Online (AJOL)

    ... of the lubricant, the atmosphere, and finally the time. In this work we present the effect of speed and load on the tribological characteristics of a Cu 8% Sn bronze pressure sintered self-lubricating mode for two lubricants with different viscosities. Keywords: sintering; powder metallurgy; tribology; lubrication; copper alloy.

  3. Portable XRF on Prehistoric Bronze Artefacts: Limitations and Use for the Detection of Bronze Age Metal Workshops

    DEFF Research Database (Denmark)

    Nørgaard, Heide Wrobel

    2017-01-01

    Two different scientific analyses—one destructive and one non destructive—were conducted on two separate groups of bronze ornaments dating from 1500–1100 BC to investigate, amongst other traits, the metal composition of their copper-tin alloys. One group of artefacts was sampled, and polished thi...

  4. RF Electromagnetic Field Treatment of Tetragonal Kesterite CZTSSe Light Absorbers

    Science.gov (United States)

    Semenenko, Mykola O.; Babichuk, Ivan S.; Kyriienko, Oleksandr; Bodnar, Ivan V.; Caballero, Raquel; Leon, Maximo

    2017-06-01

    In this work, we propose a method to improve electro-optical and structural parameters of light-absorbing kesterite materials. It relies on the application of weak power hydrogen plasma discharges using electromagnetic field of radio frequency range, which improves homogeneity of the samples. The method allows to reduce strain of light absorbers and is suitable for designing solar cells based on multilayered thin film structures. Structural characteristics of tetragonal kesterite Cu2ZnSn(S, Se)4 structures and their optical properties were studied by Raman, infrared, and reflectance spectroscopies. They revealed a reduction of the sample reflectivity after RF treatment and a modification of the energy band structure.

  5. Inhibition of surface bound carbonate stabilization of tetragonal zirconia

    DEFF Research Database (Denmark)

    Nielsen, Mette Skovgaard; Almdal, Kristoffer; Lelieveld, A. van

    2011-01-01

    Water is known to initiate a tetragonal to monoclinic phase transformation in zirconia particles. Carbonates on the zirconia surface react with water molecules and hence reduce the transformation rate. This study investigates the possibility of inhibition of the reaction between surface carbonates...... and water in order to increase the transformation rate in the zirconia crystals. It was found possible to limit the reaction by reacting the surface carbonates with alcohols, a thiol and a primary amide prior to reaction with water. It was also concluded that di- and trialcohols are able to stabilize...

  6. Light activated phase transformation of metastable tetragonal nanocrystalline zirconia

    DEFF Research Database (Denmark)

    Nielsen, Mette Skovgaard; Almdal, Kristoffer; van Lelieveld, A

    2012-01-01

    that water, HCl, HF, and NH3, all initiate phase transformation of tetragonal zirconia at room temperature, whereas NBu4Cl and NBu4OH do not. 2-(4-Methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine) was the most efficient (monoclinic volume fraction reached 0.57) out of the four tested PAGs....... For dispersion in a dimethacrylate matrix together with zirconia crystals, a monoclinic volume fraction of 0.19 was observed after 2 min of exposure to light, increasing to 0.6 after 30 min....

  7. Casting Simulation of an Austrian Bronze Age Sword Hilt

    Science.gov (United States)

    Pola, Annalisa; Mödlinger, Marianne; Piccardo, Paolo; Montesano, Lorenzo

    2015-07-01

    Bronze Age swords with a metal hilt can be considered the peak of Bronze Age casting technologies. To reconstruct the casting techniques used more than 3000 years ago, a metal hilted sword of the Schalenknauf type from Lower Austria was studied with the aid of macroscopic analyses and simulation of mold filling and casting solidification. A three-dimensional model of the hilt was created based on optical scanner measurements performed on a hilt recently discovered during archaeological excavations. Three different configurations of the gating system were considered, two on the pommel disk and one on the knob, and the effect of its location on the formation of casting defects was investigated. Three-dimensional computed tomography was used to detect internal defects, such as gas and shrinkage porosity, which were then compared with those calculated by simulation. The best match between actual and predicted hilt quality demonstrated the location of the gating system, which turned out to be on the pommel disk.

  8. Bronze Vessels with Over Vase Looped Handle of Capenate Manufacture

    Directory of Open Access Journals (Sweden)

    Nicolò Donati

    2012-10-01

    Full Text Available In the work presented we attempted to clarify the particular bronze vascular forms herein defined recipienti troncoconici ad ansa sormontante (“over vase loop handled frustoconical vessels”, often called mug, caccabus or kettle. Through a morphological analysis of the bronze vessel we proposed a hypothesized purpose of infusion or sauce preparation or a spiced wine container. The contextual analysis made it possible to date the articles between the mid-third and half of the second century BC, although some clues can extend the upper limit toward the end of the fourth century BC. The data context also allowed to suggest the site of Capena as production centre, since 31 of the 67 specimens come from the neighboring necropoles.

  9. Nettle as a distinct Bronze Age textile plant.

    Science.gov (United States)

    Bergfjord, C; Mannering, U; Frei, K M; Gleba, M; Scharff, A B; Skals, I; Heinemeier, J; Nosch, M-L; Holst, B

    2012-01-01

    It is generally assumed that the production of plant fibre textiles in ancient Europe, especially woven textiles for clothing, was closely linked to the development of agriculture through the use of cultivated textile plants (flax, hemp). Here we present a new investigation of the 2800 year old Lusehøj Bronze Age Textile from Voldtofte, Denmark, which challenges this assumption. We show that the textile is made of imported nettle, most probably from the Kärnten-Steiermark region, an area which at the time had an otherwise established flax production. Our results thus suggest that the production of woven plant fibre textiles in Bronze Age Europe was based not only on cultivated textile plants but also on the targeted exploitation of wild plants. The Lusehøj find points to a hitherto unrecognized role of nettle as an important textile plant and suggests the need for a re-evaluation of textile production resource management in prehistoric Europe.

  10. Rewriting the Central European Early Bronze Age Chronology: Evidence from Large-Scale Radiocarbon Dating.

    Science.gov (United States)

    Stockhammer, Philipp W; Massy, Ken; Knipper, Corina; Friedrich, Ronny; Kromer, Bernd; Lindauer, Susanne; Radosavljević, Jelena; Wittenborn, Fabian; Krause, Johannes

    2015-01-01

    The transition from the Neolithic to the Early Bronze Age in Central Europe has often been considered as a supra-regional uniform process, which led to the growing mastery of the new bronze technology. Since the 1920s, archaeologists have divided the Early Bronze Age into two chronological phases (Bronze A1 and A2), which were also seen as stages of technical progress. On the basis of the early radiocarbon dates from the cemetery of Singen, southern Germany, the beginning of the Early Bronze Age in Central Europe was originally dated around 2300/2200 BC and the transition to more complex casting techniques (i.e., Bronze A2) around 2000 BC. On the basis of 140 newly radiocarbon dated human remains from Final Neolithic, Early and Middle Bronze Age cemeteries south of Augsburg (Bavaria) and a re-dating of ten graves from the cemetery of Singen, we propose a significantly different dating range, which forces us to re-think the traditional relative and absolute chronologies as well as the narrative of technical development. We are now able to date the beginning of the Early Bronze Age to around 2150 BC and its end to around 1700 BC. Moreover, there is no transition between Bronze (Bz) A1 and Bronze (Bz) A2, but a complete overlap between the type objects of the two phases from 1900-1700 BC. We thus present a revised chronology of the assumed diagnostic type objects of the Early Bronze Age and recommend a radiocarbon-based view on the development of the material culture. Finally, we propose that the traditional phases Bz A1 and Bz A2 do not represent a chronological sequence, but regionally different social phenomena connected to the willingness of local actors to appropriate the new bronze technology.

  11. Rewriting the Central European Early Bronze Age Chronology: Evidence from Large-Scale Radiocarbon Dating.

    Directory of Open Access Journals (Sweden)

    Philipp W Stockhammer

    Full Text Available The transition from the Neolithic to the Early Bronze Age in Central Europe has often been considered as a supra-regional uniform process, which led to the growing mastery of the new bronze technology. Since the 1920s, archaeologists have divided the Early Bronze Age into two chronological phases (Bronze A1 and A2, which were also seen as stages of technical progress. On the basis of the early radiocarbon dates from the cemetery of Singen, southern Germany, the beginning of the Early Bronze Age in Central Europe was originally dated around 2300/2200 BC and the transition to more complex casting techniques (i.e., Bronze A2 around 2000 BC. On the basis of 140 newly radiocarbon dated human remains from Final Neolithic, Early and Middle Bronze Age cemeteries south of Augsburg (Bavaria and a re-dating of ten graves from the cemetery of Singen, we propose a significantly different dating range, which forces us to re-think the traditional relative and absolute chronologies as well as the narrative of technical development. We are now able to date the beginning of the Early Bronze Age to around 2150 BC and its end to around 1700 BC. Moreover, there is no transition between Bronze (Bz A1 and Bronze (Bz A2, but a complete overlap between the type objects of the two phases from 1900-1700 BC. We thus present a revised chronology of the assumed diagnostic type objects of the Early Bronze Age and recommend a radiocarbon-based view on the development of the material culture. Finally, we propose that the traditional phases Bz A1 and Bz A2 do not represent a chronological sequence, but regionally different social phenomena connected to the willingness of local actors to appropriate the new bronze technology.

  12. Prevention of Dealloying in Manganese Aluminium Bronze Propeller: Part II

    OpenAIRE

    Napachat Tareelap; Kaysinee Sriraksasin; Nakorn Srisukhumbowornchai; Swieng Thuanboon; Choochat Nitipanyawong

    2014-01-01

    Due to the failure of manganese aluminium bronze (MAB) propeller caused by dealloying corrosion as described in Part I [1], this work aims to study the prevention of dealloying corrosion using aluminium and zinc sacrificial anodes. The results indicated that both of the sacrificial anodes could prevent the propeller from dealloying. Moreover, the dealloying in seawater was less than that found in brackish water. It was possible that hydroxide ions, from cathodic reaction, reacted with calcium...

  13. Model of Cu-Al-Fe-Ni Bronze Crystallization

    Directory of Open Access Journals (Sweden)

    Pisarek B. P.

    2013-09-01

    Full Text Available According to the analysis of the current state of the knowledge shows that there is little information on the process of phase transformations that occur during the cooling Cu-Al-Fe-Ni hypo-eutectoid bronzes with additions of Cr, Mo and/or W, made additions individually or together, for the determination of: the type of crystallizing phases, crystallizing phases, order and place of their nucleation. On the basis of recorded using thermal and derivative analysis of thermal effects phases crystallization or their systems, analysis of the microstructure formed during crystallization - observed on the metallographic specimen casting ATD10-PŁ probe, analysis of the existing phase equilibrium diagrams forming elements tested Cu-Al-Fe-Ni bronze, with additions of Cr, Mo, W and/or Si developed an original model of crystallization and phase transformation in the solid state, the casting of high quality Cu-Al-Fe-Ni bronze comprising: crystallizing type phase, crystallizing phase sequence, place of nucleation.

  14. Investigations on dry sliding of laser cladded aluminum bronze

    Directory of Open Access Journals (Sweden)

    Freiße Hannes

    2016-01-01

    Full Text Available The aim of this study was to investigate the tribological behaviour of laser cladded aluminum bronze tool surfaces for dry metal forming. In a first part of this work a process window for cladding aluminum bronze on steel substrate was investigated to ensure a low dilution. Therefore, the cladding speed, the powder feed rate, the laser power and the distance between the process head and the substrate were varied. The target of the second part was to investigate the influence of different process parameters on the tribological behaviour of the cladded tracks. The laser claddings were carried out on both aluminum bronze and cold work tool steel as substrate materials. Two different particle sizes of the cladding powder material were used. The cladding speed was varied and a post-processing laser remelting treatment was applied. It is shown that the tribological behaviour of the surface in a dry oscillating ball-on-plate test is highly dependent on the substrate material. In the third part a deep drawing tool was additively manufactured by direct laser deposition. Furthermore, the tool was applied to form circular cups with and without lubrication.

  15. Matisse to Picasso: a compositional study of modern bronze sculptures.

    Science.gov (United States)

    Young, Marcus L; Schnepp, Suzanne; Casadio, Francesca; Lins, Andrew; Meighan, Melissa; Lambert, Joseph B; Dunand, David C

    2009-09-01

    Inductively coupled plasma-optical emission spectroscopy (ICP-OES) was used to determine the bulk metal elemental composition of 62 modern bronze sculptures cast in Paris in the first half of the twentieth century from the collections of The Art Institute of Chicago and the Philadelphia Museum of Art. As a result, a comprehensive survey of the alloy composition of the sculptures of many prominent European artists of the early twentieth century is presented here for the first time. The sculptures in this study consist of predominantly copper with two main alloying elements (zinc and tin). By plotting the concentrations of these two elements (zinc and tin) against each other for all the sculptures studied, three clusters of data become apparent: (A) high-zinc brass; (B) low-zinc brass; (C) tin bronze. These clusters correlate to specific foundries, which used specific casting methods (sand or lost wax) that were influenced by individual preferences and technical skills of the foundry masters. For instance, the high-zinc brass alloys (with the highest levels of tin and zinc and the lowest melting temperature) correspond to most of the Picasso sculptures, correlate with the Valsuani foundry, and are associated with the most recent sculptures (post-WWII) and with the lost-wax casting method. By expanding the ICP-OES database of objects studied, these material correlations may become useful for identifying, dating, or possibly even authenticating other bronzes that do not bear foundry marks. Figure.

  16. Friction Stir Processing Parameters and Property Distributions in Cast Nickel Aluminum Bronze

    National Research Council Canada - National Science Library

    Rosemark, Brian P

    2006-01-01

    Cast nickel-aluminum bronze (NAB) alloy is specified for many marine applications, including ship propellers, due to its excellent corrosion-resistance combined with acceptable mechanical properties...

  17. Patina in the construction of the poetic bronze image: science of materials, art and philosophy

    National Research Council Canada - National Science Library

    Silva, Claudia; Vélez, Gabriel; Colorado, Henry A

    2017-01-01

    Bronze has been positioned as the medium par excellence for sculptural production bearing the aesthetic, symbolic and poetic values that have propitiated the construction of a metallurgical archetype...

  18. Electronic properties of two-dimensional zinc oxide in hexagonal, (4,4)-tetragonal, and (4,8)-tetragonal structures by using Hybrid Functional calculation

    Science.gov (United States)

    Supatutkul, C.; Pramchu, S.; Jaroenjittichai, A. P.; Laosiritaworn, Y.

    2017-09-01

    This work reports the structures and electronic properties of two-dimensional (2D) ZnO in hexagonal, (4,8)-tetragonal, and (4,4)-tetragonal monolayer using GGA and HSE-hybrid functional. The calculated results show that the band gaps of 2D ZnO sheets are wider than those of the bulk ZnO. The hexagonal and (4,8)-tetragonal phases yield direct band gaps, which are 4.20 eV, and 4.59 eV respectively, while the (4,4)-tetragonal structure has an indirect band gap of 3.02 eV. The shrunken Zn-O bond lengths in the hexagonal and (4,8)-tetragonal indicate that they become more ionic in comparison with the bulk ZnO. In addition, the hexagonal ZnO sheet is the most energetically favourable. The total energy differences of (4,8)-tetragonal and (4,4)-tetragonal sheets from that of hexagonal monolayer (per formula unit) are 197 meV and 318 meV respectively.

  19. Tetragonal and collapsed-tetragonal phases of CaFe2As2 : A view from angle-resolved photoemission and dynamical mean-field theory

    Science.gov (United States)

    van Roekeghem, Ambroise; Richard, Pierre; Shi, Xun; Wu, Shangfei; Zeng, Lingkun; Saparov, Bayrammurad; Ohtsubo, Yoshiyuki; Qian, Tian; Sefat, Athena S.; Biermann, Silke; Ding, Hong

    2016-06-01

    We present a study of the tetragonal to collapsed-tetragonal transition of CaFe2As2 using angle-resolved photoemission spectroscopy and dynamical mean field theory-based electronic structure calculations. We observe that the collapsed-tetragonal phase exhibits reduced correlations and a higher coherence temperature due to the stronger Fe-As hybridization. Furthermore, a comparison of measured photoemission spectra and theoretical spectral functions shows that momentum-dependent corrections to the density functional band structure are essential for the description of low-energy quasiparticle dispersions. We introduce those using the recently proposed combined "screened exchange + dynamical mean field theory" scheme.

  20. Magnetic antiskyrmions above room temperature in tetragonal Heusler materials

    Science.gov (United States)

    Nayak, Ajaya K.; Kumar, Vivek; Ma, Tianping; Werner, Peter; Pippel, Eckhard; Sahoo, Roshnee; Damay, Franoise; Rößler, Ulrich K.; Felser, Claudia; Parkin, Stuart S. P.

    2017-08-01

    Magnetic skyrmions are topologically stable, vortex-like objects surrounded by chiral boundaries that separate a region of reversed magnetization from the surrounding magnetized material. They are closely related to nanoscopic chiral magnetic domain walls, which could be used as memory and logic elements for conventional and neuromorphic computing applications that go beyond Moore’s law. Of particular interest is ‘racetrack memory’, which is composed of vertical magnetic nanowires, each accommodating of the order of 100 domain walls, and that shows promise as a solid state, non-volatile memory with exceptional capacity and performance. Its performance is derived from the very high speeds (up to one kilometre per second) at which chiral domain walls can be moved with nanosecond current pulses in synthetic antiferromagnet racetracks. Because skyrmions are essentially composed of a pair of chiral domain walls closed in on themselves, but are, in principle, more stable to perturbations than the component domain walls themselves, they are attractive for use in spintronic applications, notably racetrack memory. Stabilization of skyrmions has generally been achieved in systems with broken inversion symmetry, in which the asymmetric Dzyaloshinskii-Moriya interaction modifies the uniform magnetic state to a swirling state. Depending on the crystal symmetry, two distinct types of skyrmions have been observed experimentally, namely, Bloch and Néel skyrmions. Here we present the experimental manifestation of another type of skyrmion—the magnetic antiskyrmion—in acentric tetragonal Heusler compounds with D2d crystal symmetry. Antiskyrmions are characterized by boundary walls that have alternating Bloch and Néel type as one traces around the boundary. A spiral magnetic ground-state, which propagates in the tetragonal basal plane, is transformed into an antiskyrmion lattice state under magnetic fields applied along the tetragonal axis over a wide range of temperatures

  1. Far infrared and Raman response in tetragonal PZT ceramic films

    Energy Technology Data Exchange (ETDEWEB)

    Buixaderas, E.; Kadlec, C.; Vanek, P.; Drnovsek, S.; Ursic, H.; Malic, B.

    2015-07-01

    PbZr{sub 0}.38Ti{sub 0}.62O{sub 3} and PbZr{sub 0}.36Ti{sub 0}.64{sub O}3 thick films deposited by screen printing on (0 0 0 1) single crystal sapphire substrates and prepared at two different sintering temperatures, were studied by Fourier-transform infrared reflectivity, time-domain TH{sub z} transmission spectroscopy and micro-Raman spectroscopy. The dielectric response is discussed using the Lichtenecker model to account for the porosity of the films and to obtain the dense bulk dielectric functions. Results are compared with bulk tetragonal PZT 42/58 ceramics. The dynamic response in the films is dominated by an overdamped lead-based vibration in the TH{sub z} range, as known in PZT, but its evaluated dielectric contribution is affected by the porosity and roughness of the surface. (Author)

  2. Modeling the Mechanical Response of Tetragonal Lysozyme Crystals

    Science.gov (United States)

    Zamiri, Amir; De, Suvranu

    2011-01-01

    In this paper we investigate the mechanical response of tetragonal lysozyme crystals based on existing experimental data and a continuum-based crystal plasticity model. Compression analyses along different crystallographic directions reveal that the mechanical response of lysozyme crystals is highly anisotropic and orientation dependent. While the response is purely elastic along the [110] direction, it is elasto-plastic along the [100] and [2̄ 12] directions. The yield stress and critical resolved shear stress are observed to be sensitive to temperature and the amount of intracrystalline water. An increase in temperature and the amount of intracrystalline water molecules leads to a decrease in the critical resolved shear stress of the slip systems and makes the crystal softer. The analysis presented in this paper may be applied to the study of other protein crystal systems as well as their optimal design for biotechnological applications. PMID:20039601

  3. Evaluation of Non-Timber forest Products (NTFPs) In Bronze Casting ...

    African Journals Online (AJOL)

    Evaluation of NTFPs input in bronze casting at Igun Street in Benin City was carried out with the use of measurement of inputs and questionnaires. Fifty percent sampling intensity was used to obtain 42 from the total population of 84 Bronze Casters. Data were analyzed with the use of descriptive statistics of frequency, ...

  4. Evaluation of Non-Timber forest Products (NTFPs) In Bronze Casting ...

    African Journals Online (AJOL)

    Michael Horsfall

    Evaluation of Non-Timber forest Products (NTFPs) In Bronze Casting Enterprise at. Egun Street, Benin City, Edo state. *KALU, C; AIGBOBO, E N. Department of Forestry and Wildlife, Faculty of Agriculture, University of Benin, Benin City. ABSTRACT: Evaluation of NTFPs input in bronze casting at Igun Street in Benin City was ...

  5. The Origin and Development of the Guild of Bronze Casters of Benin ...

    African Journals Online (AJOL)

    The guild of bronze casters was the most important guild that existed in the kingdom partly because of its function of preserving the history of the kingdom in bronze for posterity sake. A role it continued to play until the late 19th century when Benin kingdom was invaded. The outcome of the invasion was the fizzling out of the ...

  6. Metallography and microstructure interpretation of some archaeological tin bronze vessels from Iran

    Energy Technology Data Exchange (ETDEWEB)

    Oudbashi, Omid, E-mail: o.oudbashi@aui.ac.ir [Department of Conservation of Historic Properties, Faculty of Conservation, Art University of Isfahan, Hakim Nezami Street, Sangtarashha Alley, P.O. Box 1744, Isfahan (Iran, Islamic Republic of); Davami, Parviz, E-mail: pdavami@razi-foundation.com [Faculty of Material Science and Engineering, Sharif University of Technology/Razi Applied Science Foundation, No. 27, Fernan St., Shahid Ghasem Asghari Blvd., km 21 of Karadj Makhsous Road, Tehran (Iran, Islamic Republic of)

    2014-11-15

    Archaeological excavations in western Iran have recently revealed a significant Luristan Bronzes collection from Sangtarashan archaeological site. The site and its bronze collection are dated to Iron Age II/III of western Iran (10th–7th century BC) according to archaeological research. Alloy composition, microstructure and manufacturing technique of some sheet metal vessels are determined to reveal metallurgical processes in western Iran in the first millennium BC. Experimental analyses were carried out using Scanning Electron Microscopy–Energy Dispersive X-ray Spectroscopy and Optical Microscopy/Metallography methods. The results allowed reconstructing the manufacturing process of bronze vessels in Luristan. It proved that the samples have been manufactured with a binary copper–tin alloy with a variable tin content that may relates to the application of an uncontrolled procedure to make bronze alloy (e.g. co-smelting or cementation). The presence of elongated copper sulphide inclusions showed probable use of copper sulphide ores for metal production and smelting. Based on metallographic studies, a cycle of cold working and annealing was used to shape the bronze vessels. - Highlights: • Sangtarashan vessels are made by variable Cu-Sn alloys with some impurities. • Various compositions occurred due to applying uncontrolled smelting methods. • The microstructure represents thermo-mechanical process to shape bronze vessels. • In one case, the annealing didn’t remove the eutectoid remaining from casting. • The characteristics of the bronzes are similar to other Iron Age Luristan Bronzes.

  7. ISOTOPES, PLANTS, AND RESERVOIR EFFECTS : CASE STUDY FROM THE CASPIAN STEPPE BRONZE AGE

    NARCIS (Netherlands)

    Shishlina, N.; Zazovskaya, E.; van der Plicht, J.; Sevastyanov, V.; Boaretto, E.; Rebollo Franco, N.R.

    2012-01-01

    Bronze Age human and animal bone collagen from several steppe Bronze Age cultures (i.e. Early Catacomb, East and West Manych Catacomb, and Lola cultures) shows large variations in delta C-13 and delta N-15 values. In general, we observed that the older the sample, the lower the delta C-13 and delta

  8. Excerpt from "IRL (In Real Life: The Bronze Documentary Project" [interview

    Directory of Open Access Journals (Sweden)

    Stephanie Tuszynski

    2011-03-01

    Full Text Available Excerpt from "IRL (In Real Life: The Bronze Documentary Project". One of the first feature-length documentary films to take on the subject of online relationships, "IRL (In Real Life" chronicles the life, death, and afterlife of an online community called The Bronze, made up of fans from the official Web site for Buffy, the Vampire Slayer.

  9. Bronze age settlement in churchyard of Gradac monastery

    Directory of Open Access Journals (Sweden)

    Peković Mirko

    2009-01-01

    Full Text Available During 2005 and 2008, a team from Republic Cultural Heritage Preservation Institute carried out preservative, sondage, archaeological and revision exploration of the Church of Holy Virgin in Gradac monastery. The 2005 exploration aim was to uncover geomorphology and characteristics of soil and its moisture penetration, to make insight in condition of ground zones, uncovering of attached structures and archaeological material, obtaining stratigraphic data, all in purpose of obtaining data for making the Main Project for preserving the Church of Holy Virgin from moisture. The first phase of work started in 2008, and it included work on western, north-western and south-western part of the church. During these explorations, 9 sondages were opened and a drainage pit, in total area of 130 m² and total depth of 3 m. Beside medieval cultural layer and medieval necropolis, a prehistoric layer of 0.5-0.6 m depth was found which was documented with four residential horizons as well with other belonging archaeological material originated in period of the end of Early Bronze Age and Middle Bronze Age. Pottery from older prehistoric layer in Gradac, which was documented with two residential horizons, mainly consists of fragments of pottery made of weaker, refined clay, with smooth surfaces and with range of colour from brownish to dark grey. These are fragments of dishes and larger spherical pots with two vertical handles on wider part of body. Some fragments are decorated with wartlike bulges or recesses made with fingers. From fine pottery, there are pear-shaped amphorae with thin sides, bowls and cups. Beside pottery, in this layer there were also few fragments of different shapes made of Rozhnac stone, flints and quartzite, part of stone axe with perforation whose upper part is shaped into secant and two fragmented millstones made of quartzlathyte, a mineral found in mountain Golija (Pl. I-III. Analogies to this pottery are found in sites in Milića Brdo

  10. Effect of degassing addition on the solidification segregation of nickel aluminum bronze

    Science.gov (United States)

    Syazwan, F.; Kavinjr, M.; Maghribi, S.; Ashraf, N.; Hadi, A.; Shayfull, Z.; Rashidi, M. M.

    2017-09-01

    The effect of degassing agent addition on the solidification segregation of Nickel Aluminum Bronze was investigated. The complex relationship between the development of the solidification microstructures and buildup of microsegregation in Nickel Aluminum Bronze was obtained by using microstructure analysis and EDS analysis. This experiment describes the characterization of microsegregation in Nickel Aluminum Bronze which was made using point to count microanalysis along the microstructure. With this method, the differences of elements distribution in alloys solidified in the microstructure were clearly evidenced. The results show a microstructure directly affected by segregation of elements in Nickel Aluminum Bronze matrix. There is segregation of elements in the Late To Freeze (LTF) region after solidification from melting. As for degassing treatment, higher degassing addition on the Nickel Aluminum Bronze increased the elements segregation.

  11. Chisels in the italian Bronze Age: technological and typological aspects

    Directory of Open Access Journals (Sweden)

    Speciale, Claudia

    2010-12-01

    Full Text Available Bronze chisels are tools used “à percussion posée”; this means they need a minimum length and some functional parts (tang, body, blade; they could have a handle of perishable material and they were used with a hammer to work wood, bronze and other materials. Chisels can be classified following their functional parts; the first element is the shape (rod or socketed chisel; the second one is body section; the third one is tang section. Chronology and distribution of every type were identified to obtain a general view of this class of tools during the Italian Bronze Age.

    Los cinceles de bronce son herramientas que se utilizan en percusión apoyada (à percussion posée, por consiguiente, necesitan una longitud mínima y algunas partes funcionales (empuñadura, cuerpo, hoja; podrían tener un mango de material perecedero. Se utilizan con un martillo en el labrado de la madera, del bronce y de otros materiales. Los cinceles se pueden clasificar de acuerdo con los siguientes elementos funcionales: el primero es la forma (cincel de varilla o de cubo; el segundo es la sección del cuerpo; el tercero es la sección de la empuñadura. La cronología y la distribución de cada tipo se identificaron para obtener una visión general de esta clase de instrumentos durante la Edad del Bronce en Italia.

  12. Prevention of Dealloying in Manganese Aluminium Bronze Propeller: Part II

    Directory of Open Access Journals (Sweden)

    Napachat Tareelap

    2014-03-01

    Full Text Available Due to the failure of manganese aluminium bronze (MAB propeller caused by dealloying corrosion as described in Part I [1], this work aims to study the prevention of dealloying corrosion using aluminium and zinc sacrificial anodes. The results indicated that both of the sacrificial anodes could prevent the propeller from dealloying. Moreover, the dealloying in seawater was less than that found in brackish water. It was possible that hydroxide ions, from cathodic reaction, reacted with calcium in seawater to form calcium carbonate film protecting the propeller from corrosion.

  13. Analysis of selective laser cleaning of patina on bronze coins

    Science.gov (United States)

    Buccolieri, G.; Nassisi, V.; Torrisi, L.; Buccolieri, A.; Castellano, A.; Di Giulio, M.; Giuffreda, E.; Delle Side, D.; Velardi, L.

    2014-04-01

    The patina, is the result of a large number of chemical, electrochemical and physical processes which occur spontaneously during interaction of metal surfaces with the environment. In this work we want to analyze and remove the patina in artefacts, exposed to atmosphere for various decades. Here, experimental results about the laser cleaning of bronze coins by KrF (248 nm) and Nd:YAG (532 nm) lasers are reported. Both laser wavelengths were efficient to reduce the chlorine concentration on the surface of the coins more than 80 %, as demonstrated by Energy Dispersive X-Ray Fluorescence analyses.

  14. Environmental Roots of the Late Bronze Age Crisis

    Science.gov (United States)

    Kaniewski, David; Van Campo, Elise; Guiot, Joël; Le Burel, Sabine; Otto, Thierry; Baeteman, Cecile

    2013-01-01

    The Late Bronze Age world of the Eastern Mediterranean, a rich linkage of Aegean, Egyptian, Syro-Palestinian, and Hittite civilizations, collapsed famously 3200 years ago and has remained one of the mysteries of the ancient world since the event’s retrieval began in the late 19th century AD/CE. Iconic Egyptian bas-reliefs and graphic hieroglyphic and cuneiform texts portray the proximate cause of the collapse as the invasions of the “Peoples-of-the-Sea” at the Nile Delta, the Turkish coast, and down into the heartlands of Syria and Palestine where armies clashed, famine-ravaged cities abandoned, and countrysides depopulated. Here we report palaeoclimate data from Cyprus for the Late Bronze Age crisis, alongside a radiocarbon-based chronology integrating both archaeological and palaeoclimate proxies, which reveal the effects of abrupt climate change-driven famine and causal linkage with the Sea People invasions in Cyprus and Syria. The statistical analysis of proximate and ultimate features of the sequential collapse reveals the relationships of climate-driven famine, sea-borne-invasion, region-wide warfare, and politico-economic collapse, in whose wake new societies and new ideologies were created. PMID:23967146

  15. The Umm Al Binni Structure and Bronze Age Catastrophes

    Science.gov (United States)

    Hamacher, Duane W.

    Archaeological excavations of sites dating from 2200 BCE and 1200 BCE in the Middle East, Asia Minor, and southeast Europe provide evidence that a large scale disaster affected Bronze Age civilizations. There are numerous debates as to whether this was caused by warfare, a large-scale natural disaster, or some other factor. In 2001, Sharad Master used satellite images to discover a possible Holocene impact structure in the Al 'Amarah marshes of southern Iraq, known as Umm al Binni lake. With an estimated age of impact, I show that although destructive forces would have damaged Sumerian cities within a few hundred km of the coast, it is unlikely that this single impact would have caused the large-scale destruction seen over the larger region. The impact origin of the structure is unconfirmed and any connection to Bronze Age catastrophes remains speculative. Errata: Table 4 provides a list of impact sites, three of which are associated with nickel-iron impactors and therefore cannot be from a "fragmented comet".

  16. Environmental roots of the late bronze age crisis.

    Science.gov (United States)

    Kaniewski, David; Van Campo, Elise; Guiot, Joël; Le Burel, Sabine; Otto, Thierry; Baeteman, Cecile

    2013-01-01

    The Late Bronze Age world of the Eastern Mediterranean, a rich linkage of Aegean, Egyptian, Syro-Palestinian, and Hittite civilizations, collapsed famously 3200 years ago and has remained one of the mysteries of the ancient world since the event's retrieval began in the late 19(th) century AD/CE. Iconic Egyptian bas-reliefs and graphic hieroglyphic and cuneiform texts portray the proximate cause of the collapse as the invasions of the "Peoples-of-the-Sea" at the Nile Delta, the Turkish coast, and down into the heartlands of Syria and Palestine where armies clashed, famine-ravaged cities abandoned, and countrysides depopulated. Here we report palaeoclimate data from Cyprus for the Late Bronze Age crisis, alongside a radiocarbon-based chronology integrating both archaeological and palaeoclimate proxies, which reveal the effects of abrupt climate change-driven famine and causal linkage with the Sea People invasions in Cyprus and Syria. The statistical analysis of proximate and ultimate features of the sequential collapse reveals the relationships of climate-driven famine, sea-borne-invasion, region-wide warfare, and politico-economic collapse, in whose wake new societies and new ideologies were created.

  17. The bronze signum from Timacum Maius and its cultic attribution

    Directory of Open Access Journals (Sweden)

    Petrović Vladimir

    2016-01-01

    Full Text Available The bronze signum discussed in this paper was discovered by archaeological ex­cavation on the site of Timacum Maius in 2010. Found in the area of a luxurious Roman-period building, the artefact shows a tapering body with a central conical socket similar to a spearhead socket. It is one of the twenty-three known signa of the so-called classical-type. Most of them were found in the context of the cult of Jupiter Dolichenus, and we also presume the cultic purpose of the bronze signum from Timacum Maius. A similar find comes from Jupiter Dolichenus’ shrine in Egeta on the Danube limes with an inscription that connects it directly with the Dolichenian cult, and with the First Cohort of Cretans (Cohors I Cretum, the unit which had previously been stationed at Timacus Maius. The signum from Timacum Maius is most likely also connected with the cult of Jupiter Dolichenus and chronologically belongs to a period which is much earlier than the Severan age. [Projekat Ministarstva nauke Republike Srbije, 177012: Society, spiritual and material culture and communications in prehistory and early history of the Balkans

  18. Proton ordering in tetragonal and monoclinic H2O ice

    CERN Document Server

    Yen, Fei; Berlie, Adam; Liu, Xiaodi; Goncharov, Alexander F

    2015-01-01

    H2O ice remains one of the most enigmatic materials as its phase diagram reveals up to sixteen solid phases. While the crystal structure of these phases has been determined, the phase boundaries and mechanisms of formation of the proton-ordered phases remain unclear. From high precision measurements of the complex dielectric constant, we probe directly the degree of ordering of the protons in H2O tetragonal ice III and monoclinic ice V down to 80 K. A broadened first-order phase transition is found to occur near 202 K we attribute to a quenched disorder of the protons which causes a continuous disordering of the protons during cooling and metastable behavior. At 126 K the protons in ice III become fully ordered, and for the case of ice V becoming fully ordered at 113 K forming ice XIII. Two triple points are proposed to exist: one at 0.35 GPa and 126 K where ices III, IX and V coexist; and another at 0.35 GPa and 113 K where ices V, IX and XIII coexist. Our findings unravel the underlying mechanism driving th...

  19. Thermal stability of simple tetragonal and hexagonal diamond germanium

    Science.gov (United States)

    Huston, L. Q.; Johnson, B. C.; Haberl, B.; Wong, S.; Williams, J. S.; Bradby, J. E.

    2017-11-01

    Exotic phases of germanium, that form under high pressure but persist under ambient conditions, are of technological interest due to their unique optical and electrical properties. The thermal evolution and stability of two of these exotic Ge phases, the simple tetragonal (st12) and hexagonal diamond (hd) phases, are investigated in detail. These metastable phases, formed by high pressure decompression in either a diamond anvil cell or by nanoindentation, are annealed at temperatures ranging from 280 to 320 °C for st12-Ge and 200 to 550 °C for hd-Ge. In both cases, the exotic phases originated from entirely pure Ge precursor materials. Raman microspectroscopy is used to monitor the phase changes ex situ following annealing. Our results show that hd-Ge synthesized via a pure form of a-Ge first undergoes a subtle change in structure and then an irreversible phase transformation to dc-Ge with an activation energy of (4.3 ± 0.2) eV at higher temperatures. St12-Ge was found to transform to dc-Ge with an activation energy of (1.44 ± 0.08) eV. Taken together with results from previous studies, this study allows for intriguing comparisons with silicon and suggests promising technological applications.

  20. [Effects of colorants on yttria stabilized tetragonal zirconia polycrystals powder].

    Science.gov (United States)

    Wang, Bo; Chen, Jianfeng; Zhang, Yanchun; Wang, Ru

    2015-10-01

    To evaluate the effect of Fe2O3 and CeO2 as colorants on yttria stabilized tetragonal zirconia poly-crystals (Y-TZP) powder. The spray granulation slurry of colored zirconia was prepared with different concentrations of Fe2O3 (0.15%) and CeO2 (4%), which were added in Y-TZP. Zirconia powder was made by spray granulation. The powder specimens were divided into three groups: uncolored zirconia, Fe2O3 (0.15%) zirconia, and CeO2 (4%) zirconia. The particle morphologies of the powder specimens were measured with a laser particle size analyzer and an optical microscope. The differences in D50 among the three groups were statistically significant (Pzirconia (Pzirconia showed no significant difference from group CeO2 (P>0.05). Mostly spherical powder was observed in the three groups. Fe2O3 as a colorant can affect particles, whereas CeO2 has no effect.

  1. Condensation of tetragonal zirconia polycrystals by reactive sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Chen, I-M. [Institute of Materials Science and Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Yeh, S.-W. [Institute of Materials Science and Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Chiou, S.-Y. [Department of Mold and Die Engineering, National Kaohsiung University of Applied Science, Kaohsiung, Taiwan (China); Gan Dershin [Institute of Materials Science and Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan (China)]. E-mail: dgan@mail.nsysu.edu.tw; Shen Pouyan [Institute of Materials Science and Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan (China)

    2005-11-22

    Reactive sputtering on metallic Zr target under various oxygen flow rates was employed to produce nanocrystalline zirconia condensates, which were collected on a carbon-coated collodion film for analytical electron microscopic observations. With an Ar flow rate of 28 sccm, the collected condensates are cubic and tetragonal (t-) zirconia less than 10 nm in size under 0-2 sccm oxygen flow rate and increased to 10-20 nm in size with partial t- to monoclinic (m-) zirconia transformation at 3 sccm. Between 4 and 4.5 sccm, t-zirconia polycrystals (TZP) about 20 nm in grain size were formed by coalescence of the t-zirconia condensates. Above 6 sccm, the (111) and {l_brace}100{r_brace} specific coalescence as well as random attachment prevailed to form larger (> 30 nm) individual condensates of m-zirconia as the critical size of martensitic t-m transformation is exceeded. The TZP formation can be accounted for by the small grain size, the presence of low-valence Zr cation and the lateral constraint of neighboring grains.

  2. Formation of metastable tetragonal zirconia nanoparticles: Competitive influence of the dopants and surface state

    Science.gov (United States)

    Gorban, Oksana; Synyakina, Susanna; Volkova, Galina; Gorban, Sergey; Konstantiova, Tetyana; Lyubchik, Svetlana

    2015-12-01

    The effect of the surface modification of the nanoparticles of amorphous and crystalline partially stabilized zirconia by fluoride ions on stability of the metastable tetragonal phase was investigated. Based on the DSC, titrimetry and FTIR spectroscopy data it was proven that surface modification of the xerogel resulted from an exchange of the fluoride ions with the basic OH groups. The effect of the powder pre-calcination temperature before modification on the formation of metastable tetragonal phase in partially stabilized zirconia was investigated. It was shown that the main factor of tetragonal zirconia stabilization is the state of nanoparticles surface at pre-crystallization temperatures.

  3. Formation of metastable tetragonal zirconia nanoparticles: Competitive influence of the dopants and surface state

    Energy Technology Data Exchange (ETDEWEB)

    Gorban, Oksana, E-mail: matscidep@aim.com [Donetsk Institute for Physics and Engineering named after A.A. Galkin of the NAS of Ukraine, Nauki av. 46, Kyiv 03680 (Ukraine); Synyakina, Susanna; Volkova, Galina; Gorban, Sergey; Konstantiova, Tetyana [Donetsk Institute for Physics and Engineering named after A.A. Galkin of the NAS of Ukraine, Nauki av. 46, Kyiv 03680 (Ukraine); Lyubchik, Svetlana, E-mail: s_lyubchik@yahoo.com [REQUIMTE, Universida de Nova de Lisboa, 2829-516 Caparica (Portugal)

    2015-12-15

    The effect of the surface modification of the nanoparticles of amorphous and crystalline partially stabilized zirconia by fluoride ions on stability of the metastable tetragonal phase was investigated. Based on the DSC, titrimetry and FTIR spectroscopy data it was proven that surface modification of the xerogel resulted from an exchange of the fluoride ions with the basic OH groups. The effect of the powder pre-calcination temperature before modification on the formation of metastable tetragonal phase in partially stabilized zirconia was investigated. It was shown that the main factor of tetragonal zirconia stabilization is the state of nanoparticles surface at pre-crystallization temperatures.

  4. Estimation of the initial equilibrium constants in the formation of tetragonal lysozyme nuclei

    Science.gov (United States)

    Pusey, Marc L.

    1991-01-01

    Results are presented from a study of the equilibria, kinetic rates, and the aggregation pathway which leads from a lysozyme monomer crystal to a tetragonal crystal, using dialyzed and recrystallized commercial hen eggwhite lysozyme. Relative light scattering intensity measurements were used to estimate the initial equilibrium constants for undersaturated lysozyme solutions in the tetragonal regime. The K1 value was estimated to be (1-3) x 10 exp 4 L/mol. Estimates of subsequent equilibrium constants depend on the crystal aggregation model chosen or determined. Experimental data suggest that tetragonal lysozyme crystal grows by addition of aggregates preformed in the bulk solution, rather than by monomer addition.

  5. Palaeoethnobotanical Data from the High Mountainous Early Bronze Age Settlement of Tsaghkasar-1 (Mt. Aragats, Armenia

    Directory of Open Access Journals (Sweden)

    Roman Hovsepyan

    2011-09-01

    Full Text Available Palaeoethnobotanical investigations suggest that at least part of the Early Bronze Age population of Tsaghkasar was settled and practiced agriculture in the high mountainous zone. People there appear to have cultivated hexa‐ and tetraploid wheats (probably bread wheat and emmer and barley (possibly hulled. Bronze Age agriculture in the Southern Caucasus differs from earlier and later period when cultivation of pulses, oil‐producing plants, and other plants was common. This emphasis on the cultivation and use of certain cereal grains at Early Bronze sites such as Tsaghkasar can tentatively be added to a constellation of practices associated with the Kura‐Araxes culture in the South Caucasus.

  6. History of a Bronze Age tell and its environment

    Science.gov (United States)

    Kovács, Gabriella; Füleky, György; Vicze, Magdolna

    2016-04-01

    Százhalombatta-Földvár is the most excessively researched Bronze Age tell site in Hungary. Parallel to the investigation of the settlement structure and activity patterns the changes of the landscape and the effect of human alteration is also studied. Significant changes of the landscape can be detected from the Bronze Age until the recent natural and cultural heritage protection of the area. Archaeological, soil analytical and thin section soil micromorphological methods are used to reconstruct the past 4000 years of the tell and its immediate surroundings. Prior to the Bronze Age the area was covered by forest vegetation, so the initial settling could only be realised after deforestation (2000 BC). The result of the soil corings and the prepared soil thin sections are solid proves of this action. It also became evident that at some areas - so far it seems that at locales where house floors were laid for the very first time - even the topsoil was removed so intensively that only the B horizon of the relict forest soil can be found. This observation needs to be further tested outside the habitation area to define the horizontal extension of the forest clearance and the topsoil removal. The northern side of the settlement is bordered by a natural erosion gully. At 2000 BC it was just a natural depression, but by 1500 BC it was deepened to serve as a fortification ditch. Around 1200 BC the ditch started to be filled in and by 1000 BC it was refilled to such an extent that its surface was utilised again. At about 600 BC (Late Iron Age) a smaller inner rampart was erected on the southern side of the ditch for inner separation. Not much is known about the Roman period of this area (200 AD) but the remnants of a watchtower indicate their presence. During the 18th century AD the area was used for grape cultivation and later for hobby gardens up until the protection of the area in the late 20th century. Since then species of the original vegetation started to grow back

  7. Modeling the Growth Rates of Tetragonal Lysozyme Crystal Faces

    Science.gov (United States)

    Li, Meirong; Nadarajah, Arunan; Pusey, Marc L.

    1998-01-01

    The measured macroscopic growth rates of the (110) and (101) faces of tetragonal lysozyme show an unexpectedly complex dependence on the supersaturation. The growth rates decay asymptotically to zero when the supersaturation is lowered to zero and increase rapidly when the supersaturation is increased. When supersaturations are increased still further the growth rates attain a maximum before starting to decrease. However, growth of these crystals is known to proceed by the classical dislocation and 2D nucleation growth mechanisms. This anomaly can be explained if growth is assumed to occur not by monomer units but by lysozyme aggregates. Analysis of the molecular packing of these crystals revealed that they were constructed of strongly bonded 4(sub 3) helices, while weaker bonds were responsible for binding the helices to each other. It follows that during crystal growth the stronger bonds are formed before the weaker ones. Thus, the growth of these crystals could be viewed as a two step process: aggregate growth units corresponding to the 4(sub 3) helix are first formed in the bulk solution by stronger intermolecular bonds and then attached to the crystal face by weaker bonds on dislocation hillocks or 2D islands. This will lead to a distribution of aggregates in the solution with monomers and lower order aggregates being predominant at low supersaturations and higher order aggregates being predominant at high supersaturations. If the crystal grows mostly by higher order aggregates, such as tetramers and octamers, it would explain the anomalous dependence of the growth rates on the supersaturation. Besides the analysis of molecular packing, a comprehensive analysis of the measured (110) and (101) growth rates was also undertaken in this study. The distribution of aggregates in lysozyme nutrient solutions at various solution conditions were determined from reversible aggregation reactions at equilibrium. The supersaturation was defined for each aggregate species

  8. LAMQS analysis applied to ancient Egyptian bronze coins

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, L., E-mail: lorenzo.torrisi@unime.i [Dipartimento di Fisica dell' Universita di Messina, Salita Sperone, 31, 98166 Messina (Italy); Caridi, F.; Giuffrida, L.; Torrisi, A. [Dipartimento di Fisica dell' Universita di Messina, Salita Sperone, 31, 98166 Messina (Italy); Mondio, G.; Serafino, T. [Dipartimento di Fisica della Materia ed Ingegneria Elettronica dell' Universita di Messina, Salita Sperone, 31, 98166 Messina (Italy); Caltabiano, M.; Castrizio, E.D. [Dipartimento di Lettere e Filosofia dell' Universita di Messina, Polo Universitario dell' Annunziata, 98168 Messina (Italy); Paniz, E.; Salici, A. [Carabinieri, Reparto Investigazioni Scientifiche, S.S. 114, Km. 6, 400 Tremestieri, Messina (Italy)

    2010-05-15

    Some Egyptian bronze coins, dated VI-VII sec A.D. are analyzed through different physical techniques in order to compare their composition and morphology and to identify their origin and the type of manufacture. The investigations have been performed by using micro-invasive analysis, such as Laser Ablation and Mass Quadrupole Spectrometry (LAMQS), X-ray Fluorescence (XRF), Laser Induced Breakdown Spectroscopy (LIBS), Electronic (SEM) and Optical Microscopy, Surface Profile Analysis (SPA) and density measurements. Results indicate that the coins have a similar bulk composition but significant differences have been evidenced due to different constituents of the patina, bulk alloy composition, isotopic ratios, density and surface morphology. The results are in agreement with the archaeological expectations, indicating that the coins have been produced in two different Egypt sites: Alexandria and Antinoupolis. A group of fake coins produced in Alexandria in the same historical period is also identified.

  9. Influence Cr on Crystallization and the Phase Transformations of the Bronze BA1044

    Directory of Open Access Journals (Sweden)

    B. P. Pisarek

    2007-07-01

    Full Text Available The investigations were introduced in the paper, method of thermal and derivative analysis (TDA, the process of crystallization and phase transformation in the solid state of the aluminium bronze CuA110Fe4Ni4 (BA1044 and with the addition 0.3% Cr. Two intermetallic phase were identified in the microstructure of the bronze BA1044: κFel - rich in Fe and Cu and κFe2 - rich in Fe, and in the microstructure of the bronze BA1044+0.3 % Cr only one phase κFel - rich in Fe, Cu and Cr. The presence of chrome in the bronze BA1044 reduce size the primary crystals of the phase β, reduces the dynamics of the processes of thermal phase transformation in the solid state and lengthens the time their of duration.

  10. Sol-gel synthesis and XPS study of vanadium-hydroquinone oxide bronze films

    Energy Technology Data Exchange (ETDEWEB)

    Bondarenka, V. [Semiconductor Physics Institute, A. Gostauto 11, 01108 Vilnius (Lithuania); Vilnius Pedagogical University, Studentu 39, 08106 Vilnius (Lithuania); Tvardauskas, H.; Grebinskij, S.; Senulis, M.; Pasiskevicius, A. [Semiconductor Physics Institute, A. Gostauto 11, 01108 Vilnius (Lithuania); Volkov, V.; Zakharova, G. [Institute of Solid State Chemistry, Pervomaiskaia 91, 620219 Yekaterinburg (Russian Federation)

    2009-12-15

    A vanadium - hydroquinone oxide bronze has been synthesized by using a sol gel technology. The V{sub 2}O{sub 5} powder, hydrogen peroxide, and hydroquinone C{sub 6}H{sub 4}(OH){sub 2} were used as the starting materials to produce the bronze. At first the vanadium gel was made by the dissolving of vanadium pentoxide powder in hydrogen peroxide at 273 K. Then the solution was heated up to 350 K for the dissociation of peroxide complexes. An aqueous solution of hydroquinone was mixed with the formed gel in molar ratio 0.33:1. In this way the V{sub 2}O{sub 5{+-}}{sub {delta}}.nH{sub 2}O/HQ (HQ-hydroquinone) gel was synthesized. These gels are applied on the Ni pad and dried in an air (wet gel synthesis) or heated up to 580 K in air for 1 h for the water removal from gel (bronze production). The wet gel, as well as a bronze, was investigated by means of XPS method. Analysis of V-O region of XPS spectra shows that vanadium in both cases (wet gel and bronze) is in stable V{sup 5+} state. Oxygen in wet gel can be associated with V ions, hydroxide group and water. In bronze oxygen is connected with V and hydrogen (hydroxide). (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Characterisation of Late Bronze Age large size shield nails by EDXRF, micro-EDXRF and X-ray digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, E., E-mail: elin@itn.pt [Instituto Tecnologico e Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); CENIMAT/I3N, Departamento de Ciencia dos Materiais, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Monte de Caparica (Portugal); Departamento de Conservacao e Restauro, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Monte de Caparica (Portugal); Araujo, M.F. [Instituto Tecnologico e Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Silva, R.J.C. [CENIMAT/I3N, Departamento de Ciencia dos Materiais, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Monte de Caparica (Portugal); Senna-Martinez, J.C. [Centro de Arqueologia (Uniarq), Faculdade de Letras, Universidade de Lisboa, 1600-214 Lisboa (Portugal); Ines Vaz, J.L. [Departamento de Letras, Universidade Catolica, Estrada da Circunvalacao, 3504-505 Viseu (Portugal)

    2011-09-15

    In the present study six exceptional large size metallic nails, a dagger and a sickle from the Late Bronze Age archaeological site of Figueiredo das Donas (Central Portugal) have been analysed by EDXRF, micro-EDXRF and X-ray digital radiography for the study of material composition and technology of fabrication. The combination of these analytical and examination techniques showed that all artefacts are made of bronze with As, Sb and Pb impurities, and that the nails were most likely manufactured using the casting-on technique. These results reinforce the use of binary bronze by Late Bronze Age in the region, and the incorporation of new fabrication technologies that resulted from ancient spheres of interaction. - Highlights: > EDXRF, micro-EDXRF and X-ray digital radiography in cultural heritage studies. > Archaeometallurgical study of a Late Bronze Age artefact collection from Portugal. > Practise of a specific and traditional bronze metallurgy. > Appearance of technological innovations as the casting-on technique.

  12. Necropolis on Bor lake: New reports on Bronze age burial

    Directory of Open Access Journals (Sweden)

    Kapuran Aleksandar

    2011-01-01

    Full Text Available This article deals with the social and anthropological aspects of burial rituals during the Middle Bronze Age in Timočka Krajina. Decades of systematic research of necropolises and reconnaissance in the basin of the Crni Timok proved an increase in number of sites around ore - rich areas of the east Kučaj mountains as well as around Romuliana site and the fertile valleys of Džanovo polje (Map. 1. The quantitative increase in settlements was reflected by the emergence of large necropolises, only three of which have been systematically explored; those in Trnjani, Magura and Bor Lake (Fig. 1; Plan 1. Analysis of geographical features of many settlements and their position in relation to natural resources helped define two communities, one of which carried out mining and metallurgical activities, while the other group engaged in the production of food. Both groups lived in the immediate vicinity and mutual dependence, functioning within a developed market for copper production. During the exploration of the necropolis near Bor Lake in 1997, the remains of burnt skeletons were collected from burial structures 2/97 and 13/97 (Fig. 2; Plans 2 and 3. Anthropological analysis of the cremated remains of the deceased showed that high temperatures were used during the cremation process, which we assume could have only been achieved in metallurgical furnaces. This is confirmed by the fact that the skeletal fragments contain traces of melted metal, as well as finds of bronze slag inside urns and grave structures in the necropolis in Trnjani (Figs. 3 and 4; Tables 1-4. Burial ritual of this kind was not proved by systematic archaeological research of necropolises in the basin of Crni Timok, although anthropological data collected from necropolises linked to metallurgical settlements may indicate some guidelines in the ritual cremation of prominent members of these communities. [Projekat Ministarstva nauke Republike Srbije, br. 177020: Arheologija Srbije

  13. Laser recleaning of a Bronze Age prehistoric dolmen

    Science.gov (United States)

    Daurelio, G.; Andriani, S. E.; Catalano, I. M.; Albanese, A.

    2007-05-01

    Dolmen La Chianca (XVI-XV century B.C.) is one of the most important megalithic buildings in Europe for its state of conservation and for the great number of findings that were discovered there (human remains, ceramic vases, pendants, bronze objects, obsidian and silica blades etc.). The building was defaced by many writings made using different markers (permanent black, correction ink pen, ballpoint pen, pencil, water-based coloured markers). The writings were removed by using a Nd-YAG laser source (λ 1064 nm with pulse duration; t 8 ns ; f 2 to 20 Hz ; energy per impulse up to 280 mJ). Degradation mapping and laser cleaning with photographs, taken before, during and after the process in situ, were carried out, then different laser parameters and techniques were used to remove different ink types. A first laser cleaning was operated on the same building in 1999 by Daurelio, but vandals defaced newly the monument, then a new restoration became necessary.

  14. Tracing the dynamic life story of a Bronze Age Female

    Science.gov (United States)

    Margarita Frei, Karin; Mannering, Ulla; Kristiansen, Kristian; Allentoft, Morten E.; Wilson, Andrew S.; Skals, Irene; Tridico, Silvana; Louise Nosch, Marie; Willerslev, Eske; Clarke, Leon; Frei, Robert

    2015-05-01

    Ancient human mobility at the individual level is conventionally studied by the diverse application of suitable techniques (e.g. aDNA, radiogenic strontium isotopes, as well as oxygen and lead isotopes) to either hard and/or soft tissues. However, the limited preservation of coexisting hard and soft human tissues hampers the possibilities of investigating high-resolution diachronic mobility periods in the life of a single individual. Here, we present the results of a multidisciplinary study of an exceptionally well preserved circa 3.400-year old Danish Bronze Age female find, known as the Egtved Girl. We applied biomolecular, biochemical and geochemical analyses to reconstruct her mobility and diet. We demonstrate that she originated from a place outside present day Denmark (the island of Bornholm excluded), and that she travelled back and forth over large distances during the final months of her life, while consuming a terrestrial diet with intervals of reduced protein intake. We also provide evidence that all her garments were made of non-locally produced wool. Our study advocates the huge potential of combining biomolecular and biogeochemical provenance tracer analyses to hard and soft tissues of a single ancient individual for the reconstruction of high-resolution human mobility.

  15. Bronze baby syndrome and the risk of kernicterus.

    Science.gov (United States)

    Bertini, Giovanna; Dani, Carlo; Fonda, Claudio; Zorzi, Carlo; Rubaltelli, Firmino F

    2005-07-01

    The problem of kernicterus in infants with bronze baby syndrome (BBS) has been reviewed on the basis of cases reported in the literature. In addition, a new case concerning an infant with severe Rh haemolytic disease, who presented with BBS and who has developed neurological manifestations of kernicterus with magnetic resonance images showing basal ganglia abnormalities, is presented. In this patient, the total serum bilirubin (TSB) concentration ranged from 18.0 to 22.8 mg/dl (306 to 388 micromol/l) and the bilirubin/albumin (B/A) ratio was 6.0 (mg/g) (6.8 is the value at which an exchange transfusion should be considered). The case presented is important due to the fact that kernicterus appeared after an exchange transfusion was performed when the TSB level reached 22.8 mg/dl (388 micromol/l) on 6th day of life while the haematocrit was 30%. From this case and from other cases reported in the literature, we must stress that, even if the level at which hyperbilirubinemia poses a threat remains undefined, BBS may constitute an additional risk of developing kernicterus. The possible strategies for implementing an approach to the management of hyperbilirubinemia (especially the haemolytic kind) in the presence of BBS may include an exchange transfusion carried out at lower TSB concentration than previously recommended or an early administration of Sn-mesoporphyrin.

  16. Hydrothermal synthesis of tetragonal BaTiO3 nanotube arrays with high dielectric performance.

    Science.gov (United States)

    Wang, Liming; Deng, Xiangyun; Li, Jianbao; Liao, Xinxing; Zhang, Guoqing; Wang, Chunpeng; Su, Kuifan

    2014-06-01

    Tetragonal Barium titanate (BaTiO3) nanotube arrays have been prepared using the template-assisted hydrothermal method combined with an annealing process. The in-situ chemical conversion of TiO2 nanotube array templates ensured that BaTiO3 maintained the morphology of the nanotube architectures. Moreover, X-ray diffraction and Raman spectrum characterization were used to confirm that the BaTiO3 nanotube arrays had a tetragonal phase after the use of a simple annealing technique. Typical hysteresis loops showed their ferroelectricity, with the remanent polarization and coercive fields being 2.57 microC/cm2 and 2.52 kV/cm, respectively. The relative dielectric constant of the tetragonal BaTiO3 nanotube arrays reached up to 1000 and the dielectric loss was as low as 0.02 at 1 kHz at room temperature.

  17. Dating simple flakes: Early Bronze Age flake production technology on the Middle Euphrates Steppe, Syria

    Directory of Open Access Journals (Sweden)

    Yoshihiro Nishiaki

    2014-03-01

    Full Text Available Aceramic flint scatters, comprising very crude cores or flakes and no formalised tools, are frequently found on the Middle Euphrates steppe of northern Syria. Previous studies suggest that many of them are residues of short-term activities by the nomads or shepherds of the Early Bronze Age. In order to verify this interpretation, a more precise chronological framework needs to be established for the Early Bronze Age lithic industry. This paper analyses stratified flake assemblages of the Early Bronze Age at Tell Ghanem al-Ali, a securely radiocarbon-dated settlement on the Middle Euphrates, and examines which occupation level yields assemblages most similar to those of the steppe. Results demonstrate that the lithic industry of this period underwent significant diachronic changes in terms of core reduction technology. Based on the chronological framework developed at Tell Ghanem al-Ali, the steppe assemblages in question can be assigned to different phases of the Early Bronze Age. This finding will help identify processes at the beginning of the extensive exploitation of the steppe, which is regarded as one of the most important socioeconomic changes that occurred among Early Bronze Age communities of the Middle Euphrates.

  18. Corrosion of Bronzes by Extended Wetting with Single versus Mixed Acidic Pollutants.

    Science.gov (United States)

    Gianni, Liliana; Gigante, Giovanni E; Cavallini, Mauro; Adriaens, Annemie

    2014-04-28

    The corrosion of bronzes was examined in the context of single-acid versus mixed-acid (as in urban acid rain) solutions. Two bi-component bronzes (copper with either 3% Sn or 7% Sn) that closely represent those of historic artifacts were immersed for five weeks in conditions designed to replicate those experienced by statues and ornaments in cities where rainfall and humidity constantly produce an electrolyte layer on the surfaces of bronzes. Ions, acids, and particles of pollutants can dissolve in this layer, resulting in a variety of harsh corrosion processes. The kinetics of corrosion and the properties of the resulting patinas were monitored weekly by electrochemical impedance spectroscopy and open-circuit potential measurements. The sizes and appearances of the corrosion products were monitored and used to estimate the progress of the corrosion, whose crystalline structures were visualized using scanning electron microscopy with energy dispersive spectroscopy, identified by X-ray diffraction, and characterized by spectrocolorimetry. The electrochemical measurements demonstrated that greater damage (in terms of color change and corrosion product formation) did not correspond to deficiencies in protection. The mixed-acid solution did not corrode the bronzes, as would be expected from the additive effects of the single acids. The postulated mechanisms of metal dissolution appear to be specific to a particular bronze alloy, with the tin component playing an important role.

  19. Propolis as a green corrosion inhibitor for bronze in weakly acidic solution

    Science.gov (United States)

    Varvara, Simona; Bostan, Roxana; Bobis, Otilia; Găină, Luiza; Popa, Florin; Mena, Vicente; Souto, Ricardo M.

    2017-12-01

    In the present work, the inhibitive action of natural propolis on bronze corrosion in a weakly acidic solution containing Na2SO4 and NaHCO3 at pH 5 was evaluated using multiscale electrochemical techniques, namely potentiodynamic polarization, electrochemical impedance spectroscopy and scanning vibrating electrode technique measurements. The major constituents of propolis were identified by HPLC. Surface characterization was performed by SEM-EDX and AFM analysis. Experiments were performed as a function of the propolis concentration and immersion time in the corrosive electrolyte. The obtained results showed that propolis presents good anticorrosive properties on bronze, acting as a mixed-type inhibitor, but its protective effectiveness is time-dependent. The highest inhibiting efficiency of 98.9% was obtained in the presence of 100 ppm propolis, after about 12 h of exposure to inhibitor-containing electrolyte through the stabilization of Cu2O on the bronze surface. The inhibitive properties of propolis on bronze corrosion are likely due to the adsorption of its main constituents (flavonoids and phenolic compounds), through the oxygen atoms in their functional groups and aromatic rings, which have been evidenced by FT-IR spectra. The adsorption of propolis on bronze was found to follow Langmuir adsorption isotherm.

  20. Corrosion of Bronzes by Extended Wetting with Single versus Mixed Acidic Pollutants

    Directory of Open Access Journals (Sweden)

    Liliana Gianni

    2014-04-01

    Full Text Available The corrosion of bronzes was examined in the context of single-acid versus mixed-acid (as in urban acid rain solutions. Two bi-component bronzes (copper with either 3% Sn or 7% Sn that closely represent those of historic artifacts were immersed for five weeks in conditions designed to replicate those experienced by statues and ornaments in cities where rainfall and humidity constantly produce an electrolyte layer on the surfaces of bronzes. Ions, acids, and particles of pollutants can dissolve in this layer, resulting in a variety of harsh corrosion processes. The kinetics of corrosion and the properties of the resulting patinas were monitored weekly by electrochemical impedance spectroscopy and open-circuit potential measurements. The sizes and appearances of the corrosion products were monitored and used to estimate the progress of the corrosion, whose crystalline structures were visualized using scanning electron microscopy with energy dispersive spectroscopy, identified by X-ray diffraction, and characterized by spectrocolorimetry. The electrochemical measurements demonstrated that greater damage (in terms of color change and corrosion product formation did not correspond to deficiencies in protection. The mixed-acid solution did not corrode the bronzes, as would be expected from the additive effects of the single acids. The postulated mechanisms of metal dissolution appear to be specific to a particular bronze alloy, with the tin component playing an important role.

  1. Experimental Investigation of Friction Coefficient and Wear Rate of Brass and Bronze under Lubrication Conditions

    Directory of Open Access Journals (Sweden)

    S. Senhadji

    2016-03-01

    Full Text Available The present study is conducted in order to compare the frictional and wear behaviour under mixed lubrication of two pins: bronze (CuSn9P and brass (CuZn39Pb2, sliding on a steel disc (XC42. The selection of this type of brass and bronze was made because they are not large differences in microhardness, however, have a completely different microstructure. All tests were carried out by using a pin-on-disc tribometer, with a plane contact mode and a pure sliding velocity. The results indicate that friction coefficient and the wear coefficient of brass are significantly higher in comparison to bronze for the two studied roughness (Ra = 2 and 0.15 μm. We also note that for the brass the friction is slightly affected by the roughness of the discs, and the running time is reduced. Regarding bronze, the friction passes from 0.17 for the rough disc (Ra = 2 μm to 0.02 for the smooth disc (Ra = 0.15 μm with a time of running about 2000 s; the low value of friction corresponds to the transition to a hydrodynamic regime. The analysis of the microstructure of brass shows a high shear of the surface layers, with a severe plastic deformation, which is not the case for the bronze that is not affected by observable deformations.

  2. Warm Spraying of High-Strength Ni-Al-Bronze: Cavitation Characteristics and Property Prediction

    Science.gov (United States)

    Krebs, Sebastian; Kuroda, Seiji; Katanoda, Hiroshi; Gaertner, Frank; Klassen, Thomas; Araki, Hiroshi; Frede, Simon

    2017-01-01

    Bronze materials such as Ni-Al-bronze show exceptional performances against cavitation erosion, due to their high fatigue strength and high strength. These materials are used for ship propellers, pump systems or for applications with alternating stresses. Usually, the respective parts are cast. With the aim to use resources more efficiently and to reduce costs, this study aimed to evaluate opportunities to apply bronze as a coating to critical areas of respective parts. The coatings should have least amounts of pores and non-bonded areas and any contaminations that might act as crack nuclei and contribute to material damages. Processes with low oxidation and high kinetic impacts fulfill these criteria. Especially warm spraying, a nitrogen-cooled HVOF process, with similar impact velocities as cold gas spraying but enhanced process temperature, allows for depositing high-strength Ni-Al-bronze. This study systematically simulates and evaluates the formation and performance of warm-sprayed Ni-Al-bronze coatings for different combustion pressures and nitrogen flow rates. Substrate preheating was used to improve coating adhesion for lower spray parameter sets. Furthermore, this study introduces an energy-based concept to compare spray parameter sets and to predict coating properties. Coatings with low porosities and high mechanical strengths are obtained, allowing for a cavitation resistance similar to bulk material.

  3. Depth resolved domain mapping in tetragonal SrTiO3 by micro-Laue diffraction

    Science.gov (United States)

    Merz, T. A.; Noad, H.; Xu, R.; Inoue, H.; Liu, W.; Hikita, Y.; Vailionis, A.; Moler, K. A.; Hwang, H. Y.

    2016-05-01

    We present depth resolved X-ray micro-Laue diffraction experiments on the low temperature domain structure of SrTiO3. At 80 K, monochromatic X-ray diffraction shows an elongated out-of-plane unit cell axis within a matrix of in-plane oriented tetragonal unit cells. Full deviatoric strain mappings from white beam diffraction show a dominance of two tetragonal domain orientations (x- and z-axes) over a large area of sample surface. This information sets an upper bound on domain wall widths and offers a method for studying 3D domain structure at low temperatures.

  4. Morphology of tetragonal ZrO/sub 2/ in a ternary (Mg,Y)-PSZ

    Energy Technology Data Exchange (ETDEWEB)

    Lee, R.R.; Heuer, A.H.

    1987-04-01

    The high fracture toughness of optimally-fabricated precipitation-toughened partially-stabilized ZrO/sub 2/'s (PSZ's) is due to the stress-induced martensitic transformation of tetragonal (t) precipitates to monoclinic (m) symmetry in the stress fields of propagating cracks. The precipitation of tetragonal (t) ZrO/sub 2/ in a ternary (Mg,Y)-PSZ has been studied. Nucleation of t-ZrO/sub 2/ occurs homogeneously, as in other PSZ's, and coarsened precipitates are multivariant and have an unusual tetrahedral morphology.

  5. Of farms and fields : the Bronze Age and Iron Age settlement and Celtic field at Hijken-Hijkerveld

    NARCIS (Netherlands)

    Arnoldussen, S.; de Vries, Karen M.

    2014-01-01

    Between 1969 and 1973, excavations were undertaken at Hijken, the Netherlands. An area of 3 hectares within a cultural landscape replete with barrows and Celtic field banks was opened-up and yielded Late Neolithic graves, a Bronze Age palisade and several Middle Bronze Age houses. During the Late

  6. Building the Bronze Age : Architectural and social change on the Greek mainland during Early Helladic III, Middle Helladic and Late Helladic I

    NARCIS (Netherlands)

    Wiersma, Corien

    2014-01-01

    Communities living on the Greek Mainland during the end of the Early Bronze Age (EBA. ca. 2200-2000 BC) and the earlier Middle Bronze Age (MBA, ca. 2000-1800 BC) were thought to be relatively simple and egalitarian, while during the later MBA and early Late Bronze Age (LBA, ca. 1700-1600 BC),

  7. Highly Stable Aqueous Zinc-ion Storage Using Layered Calcium Vanadium Oxide Bronze Cathode

    KAUST Repository

    Xia, Chuan

    2018-02-12

    Cost-effective aqueous rechargeable batteries are attractive alternatives to non-aqueous cells for stationary grid energy storage. Among different aqueous cells, zinc-ion batteries (ZIBs), based on Zn2+ intercalation chemistry, stand out as they can employ high-capacity Zn metal as anode material. Herein, we report a layered calcium vanadium oxide bronze as cathode material for aqueous Zn batteries. For the storage of Zn2+ ions in aqueous electrolyte, we demonstrate that calcium based bronze structure can deliver a high capacity of 340 mAh g-1 at 0.2 C, good rate capability and very long cycling life (96% retention after 3000 cycles at 80 C). Further, we investigate the Zn2+ storage mechanism, and the corresponding electrochemical kinetics in this bronze cathode. Finally, we show that our Zn cell delivers an energy density of 267 Wh kg-1 at a power density of 53.4 W kg-1.

  8. Boiling heat transfer on single phosphor bronze and copper mesh microstructures

    Directory of Open Access Journals (Sweden)

    Orman Łukasz J.

    2014-03-01

    Full Text Available The paper presents experimental results of boiling heat transfer of distilled water and ethyl alcohol on surfaces covered with single layers of wire mesh structures made of phosphor bronze and copper. For each material two kinds of structures have been considered (higher and lower in order to determine the impact of the height of the structure on boiling heat transfer. The wire diameter of the copper meshes was 0,25 mm and 0,32 mm, while of the bronze meshes: 0,20 mm and 0,25 mm. The structures had the same mesh aperture (distance between the wires – 0,50 mm for copper and 0,40 for bronze but different wire diameter and, consequently, different height of the layers. The tests have been performed under ambient pressure in the pool boiling mode. The obtained results indicate a visible impact of the layer height on the boiling heat transfer performance of the analysed microstructures.

  9. DEGRADATION WORKS OF MONUMENTAL ART CAST BRONZE UNDER THE INFLUENCE OF ENVIRONMENTAL FACTORS

    Directory of Open Access Journals (Sweden)

    Delia NICA-BADEA

    2012-11-01

    Full Text Available Intensive pollution, combined with the lack of conservation of monuments exposed to these environments make the main cause of deterioration of cultural objects to atmospheric corrosion metal. This paper proposes a study of the main factors leading to degradation Bronze alloy, cast bronze monuments exposed to open atmosphere: corrosive environmental factors, stability and products of corrosion of bronze. In general, all corrosion products present on a metal surface are indicated as 'skate', can be composed of single-layer or multilayer products. The paper also includes a case study on the influence of environmental factors on degradation Matthias monument statue in Cluj-Napoca, Romania. Visual inspection of the monument informs us that have white spots, gray, reddish not consistent with the base color green patina, surfaces showing depigmentation, the rain washed areas, crystallization, deposition of air-borne particles.

  10. Craftmanship, Production and Distribution of Metalwork in the Early and Middle Northern Bronze Age

    DEFF Research Database (Denmark)

    Nørgaard, Heide Wrobel

    possible to compare these traits between different bronze objects. Using a group of bronze objects who are already critically analyzed with regard to the formal characteristics gives a unique opportunity to recognize the workshops and their distribution areas and will be the base of the project.......Workshops and their sphere of influence is an important factor in the identification of social groups who are related to what we term workshop. Here the specialization within the workshop based on certain forms and behaviours can be linked to the knowledge of social groups. Statements about...... the origin of foreign objects can help to clarify social interaction in Bronze Age Europe. The project aims not only to find the centres of production and their distribution areas but also to examine their role in the creation of social identities. The aim is furthermore to examine the techniques used...

  11. Medical image registration algorithms assesment: Bronze Standard application enactment on grids using the MOTEUR workflow engine.

    Science.gov (United States)

    Glatard, Tristan; Montagnat, Johan; Pennec, Xavier

    2006-01-01

    Medical image registration is pre-processing needed for many medical image analysis procedures. A very large number of registration algorithms are available today, but their performance is often not known and very difficult to assess due to the lack of gold standard. The Bronze Standard algorithm is a very data and compute intensive statistical approach for quantifying registration algorithms accuracy. In this paper, we describe the Bronze Standard application and we discuss the need for grids to tackle such computations on medical image databases. We demonstrate MOTEUR, a service-based workflow engine optimized for dealing with data intensive applications. MOTEUR eases the enactment of the Bronze Standard and similar applications on the EGEE production grid infrastructure. It is a generic workflow engine, based on current standards and freely available, that can be used to instrument legacy application code at low cost.

  12. Medical image registration algorithms assesment Bronze Standard application enactment on grids using the MOTEUR workflow engine

    CERN Document Server

    Glatard, T; Pennec, X

    2006-01-01

    Medical image registration is pre-processing needed for many medical image analysis procedures. A very large number of registration algorithms are available today, but their performance is often not known and very difficult to assess due to the lack of gold standard. The Bronze Standard algorithm is a very data and compute intensive statistical approach for quantifying registration algorithms accuracy. In this paper, we describe the Bronze Standard application and we discuss the need for grids to tackle such computations on medical image databases. We demonstrate MOTEUR, a service-based workflow engine optimized for dealing with data intensive applications. MOTEUR eases the enactment of the Bronze Standard and similar applications on the EGEE production grid infrastructure. It is a generic workflow engine, based on current standards and freely available, that can be used to instrument legacy application code at low cost.

  13. THE CHARACTERIZATION OF A CORRODED EGYPTIAN BRONZE STATUE AND A STUDY OF THE DEGRADATION PHENOMENA

    Directory of Open Access Journals (Sweden)

    Mohamed GHONIEM

    2011-06-01

    Full Text Available This paper presents the results of scientific examinations carried out on an Egyptian bronze statue discovered buried in Sais. Optical Microscopy (OM, Scanning Electron Microscopy (SEM coupled with Energy Dispersive Spectroscopy (EDS and X-ray Diffraction (XRD were used to understand the corrosive morphological characteristics of the patina, to investigate the corrosion products, analyze the elementary composition of the statue and to identify the corrosive factors with effects on the alteration processes. The results indicated that the statue was made of bronze alloy, with copper as the main element, besides lead and tin. Three layers of alteration products with various composition and morphology covered the substrate of the bronze alloy. XRD results indicated that the statue was subjected to many corrosive ions such as sulfur and chloride, and buried in wet soil, rich in oxygen and carbon. This study provides useful information for the restoration and protection of the statue.

  14. Tetragonal-to-Tetragonal Phase Transition in Lead-Free (KxNa1−xNbO3 (x = 0.11 and 0.17 Crystals

    Directory of Open Access Journals (Sweden)

    Dabin Lin

    2014-06-01

    Full Text Available Lead free piezoelectric crystals of (KxNa1−xNbO3 (x = 0.11 and 0.17 have been grown by the modified Bridgman method. The structure and chemical composition of the obtained crystals were determined by X-ray diffraction (XRD and electron probe microanalysis (EPMA. The domain structure evolution with increasing temperature for (KxNa1−xNbO3 (x = 0.11 and 0.17 crystals was observed using polarized light microscopy (PLM, where distinguished changes of the domain structures were found to occur at 400 °C and 412 °C respectively, corresponding to the tetragonal to tetragonal phase transition temperatures. Dielectric measurements performed on (K0.11Na0.89NbO3 crystals exhibited tetragonal to tetragonal and tetragonal to cubic phase transitions temperatures at 405 °C and 496 °C, respectively.

  15. Sodium tungsten bronze thin films by rf sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Anderegg, J.W.

    1977-03-01

    Polycrystalline Na/sub x/WO/sub 3/ films were produced by rf sputtering. Films of low x-value resulted when co-sputtering WO/sub 3/ on a Na/sub 0.83/WO/sub 3/ target, and Na/sub 0/./sub 83/ on WO/sub 3/ target. Films of high x and of mixed phase were produced by sputtering a powder mixture of Na/sub 2/WO/sub 4/ and WO/sub 3/ on a tungsten target. Of the sputtering parameters studied, the substrate temperature is the most critical with temperatures above 500/sup 0/C producing films which were cubic in structure with only a small amount of Tetragonal I. The presence of oxygen up to 3 percent by volume had minimal effect on film quality or x-value. Auger, electron microprobe, SIMS, SEM, x-ray diffraction, and sheet resistivity techniques were used in characterizing these films. Resistivity of the films was a factor of 10 higher than the bulk crystalline data for Na/sub 0/./sub 83/WO/sub 3/.

  16. Nomadic pastoralism in the Early Bronze Age of the central Balkans evaluation of background knowledge

    Directory of Open Access Journals (Sweden)

    Porčić Marko

    2008-01-01

    Full Text Available The aim of the paper is to examine background knowledge about the orga­nizational properties of mobile pastoral groups in order to assess the likelihood of the existence of pastoral nomads in the Early Bronze Age in the central Balkans. The patterning found by A. L. Johnson (2002 is taken as a point of departure for the cross-cultural analysis conducted in this study. Johnson’s findings are in the main corroborated. Acquired knowledge about the workings of pastoral societies suggests that highly mobile pastoral groups should not be expected in the Early Bronze Age of the central Balkans.

  17. Non-invasive chemical and phase analysis of Roman bronze artefacts from Thamusida (Morocco)

    Energy Technology Data Exchange (ETDEWEB)

    Gliozzo, Elisabetta, E-mail: gliozzo@unisi.i [Dipartimento di Scienze della Terra, Universita di Siena, via Laterina 8, 53100 Siena (Italy); Arletti, Rossella, E-mail: rarletti@unimore.i [Dipartimento di Scienze della Terra, Universita di Modena e Reggio Emilia, Largo S. Eufemia 19, 41100 Modena (Italy); Cartechini, Laura, E-mail: laura@thch.unipg.i [Istituto di Scienze e Tecnologie Molecolari del CNR (CNR-ISTM), c/o Dipartimento di Chimica, Universita di Perugia, via Elce di Sotto 8, 06123 Perugia (Italy); Dipartimento di Chimica, Universita di Perugia, via Elce di Sotto 8, 06123 Perugia (Italy); Imberti, Silvia, E-mail: Silvia.Imberti@stfc.ac.u [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OX11 0QX (United Kingdom); Kockelmann, Winfried A., E-mail: Winfried.Kockelmann@stfc.ac.u [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OX11 0QX (United Kingdom); Memmi, Isabella, E-mail: memmi@unisi.i [Dipartimento di Scienze della Terra, Universita di Siena, via Laterina 8, 53100 Siena (Italy); Rinaldi, Romano, E-mail: rrinaldi@unipg.i [Dipartimento di Chimica, Universita di Perugia, via Elce di Sotto 8, 06123 Perugia (Italy); Tykot, Robert H., E-mail: rtykot@cas.usf.ed [Department of Anthropology, University of South Florida, Tampa, FL 33620 (United States)

    2010-12-15

    A repertory of Roman military bronze equipment (1st- 3rd century AD) found at the archaeological site of Thamusida (Rabat, Morocco) was analysed by non-destructive X-ray fluorescence and time of flight neutron diffraction (TOF-ND). Most objects are made of leaded alloys, where copper is combined with tin and/or zinc and, in six cases, to arsenic as well. A mixed technology was employed, making a limited use of 'pure' semi-finished materials if compared with the large utilization of recycled materials (brass and bronze).

  18. Evidence of tetragonal distortion as the origin of the ferromagnetic ground state in γ -Fe nanoparticles

    Science.gov (United States)

    Augustyns, V.; van Stiphout, K.; Joly, V.; Lima, T. A. L.; Lippertz, G.; Trekels, M.; Menéndez, E.; Kremer, F.; Wahl, U.; Costa, A. R. G.; Correia, J. G.; Banerjee, D.; Gunnlaugsson, H. P.; von Bardeleben, J.; Vickridge, I.; Van Bael, M. J.; Hadermann, J.; Araújo, J. P.; Temst, K.; Vantomme, A.; Pereira, L. M. C.

    2017-11-01

    γ -Fe and related alloys are model systems of the coupling between structure and magnetism in solids. Since different electronic states (with different volumes and magnetic ordering states) are closely spaced in energy, small perturbations can alter which one is the actual ground state. Here, we demonstrate that the ferromagnetic state of γ -Fe nanoparticles is associated with a tetragonal distortion of the fcc structure. Combining a wide range of complementary experimental techniques, including low-temperature Mössbauer spectroscopy, advanced transmission electron microscopy, and synchrotron radiation techniques, we unambiguously identify the tetragonally distorted ferromagnetic ground state, with lattice parameters a =3.76 (2 )Å and c =3.50 (2 )Å , and a magnetic moment of 2.45(5) μB per Fe atom. Our findings indicate that the ferromagnetic order in nanostructured γ -Fe is generally associated with a tetragonal distortion. This observation motivates a theoretical reassessment of the electronic structure of γ -Fe taking tetragonal distortion into account.

  19. Surfactant-free hydrothermal synthesis of highly tetragonal barium titanate nanowires: a structural investigation.

    Science.gov (United States)

    Joshi, Upendra A; Yoon, Songhak; Baik, Sunggi; Lee, Jae Sung

    2006-06-29

    Barium titanate nanowires synthesized with a surfactant-free hydrothermal method have been characterized by various techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), synchrotron X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The TEM and SEM analyses show the uniform cylindrical nanowires. The Rietveld refinement with synchrotron X-ray powder diffraction showed that the lattice parameters of cubic and tetragonal phases were a (= b = c) = 4.0134 A and a (= b) = 3.9998 A, c = 4.0303 A, respectively. The final weighted R-factor, R(wp), was 6.75% and the goodness of fit indicator was 1.30. The mass fraction of tetragonal and cubic phases based on the refined scale factor for the two phases were 98.4% and 1.6%, respectively, which clearly show the nanowires are tetragonal. The XPS analysis has shown that as-obtained BaTiO3 nanowires were phase pure. The Raman spectra confirm the tetragonal phase of the BaTiO3 nanowires. The dielectric constant measurement shows the shift in the transition temperature (Tc = 105 degrees C) compared to the bulk transition temperature (Tc = 132 degrees C). The dielectric constant at Tc was 174 measured at 1 kHz frequency.

  20. Hittites and "barbarians" in the Late Bronze Age: regional survey in northern Turkey

    OpenAIRE

    Matthews, Roger

    1999-01-01

    The Hittites have attracted less attention from British archaeologists than other Bronze Age states of ancient Southwest Asia, and yet in the second millennium BC they controlled most of Anatolia and at the peak of their power they even conquered Babylon. Here the Director of the British Institute of Archaeology at Ankara describes new research on the northwest frontier of the Hittite empire.

  1. Study on surface properties of gilt-bronze artifacts, after Nd:YAG laser cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeyoun [Division of Restoration Technology, National Research Institute of Cultural Heritage, Daejeon (Korea, Republic of); Cho, Namchul, E-mail: nam1611@hanmail.net [Department of Cultural Heritage Conservation Science, Kongju National University, Gongju, 314-701 (Korea, Republic of); Lee, Jongmyoung [Laser Engineering Group, IMT Co. Ltd, Gyeonggi (Korea, Republic of)

    2013-11-01

    As numerous pores are formed at plating gilt-bronze artifacts, the metal underlying the gold is corroded and corrosion products are formed on layer of gold. Through this study, the surfaces of gilt-bronze are being investigated before and after the laser irradiation to remove corrosion products of copper by using Nd:YAG laser. For gilt-bronze specimens, laser and chemical cleaning were performed, and thereafter, surface analysis with SEM-EDS, AFM, and XPS were used to determine the surface characteristics. Experimental results show that chemical cleaning removes corrosion products of copper through dissolution but it was not removed uniformly and separated the metal substrate and the gold layer. Nevertheless, through laser cleaning, some of the corrosions were removed with some damaged areas due to certain conditions and brown residues remained. Brown residues were copper corrosion products mixed with soil left within the gilt layer. It was due to surface morphology of uneven and rough gilt layer. Hence, they did not react effectively to laser beams, and thus, remained as residues. The surface properties of gilt-bronze should be thoroughly investigated with various surface analyses to succeed in laser cleaning without damages or residues.

  2. The sodium tungsten bronzes as plasmonic materials: fabrication, calculation and characterization

    Science.gov (United States)

    Tegg, Levi; Cuskelly, Dylan; Keast, Vicki J.

    2017-06-01

    The tungsten bronzes are non-stoichiometric transition metal oxides of the form M x WO3, where 0  ⩽  x  ⩽  1, and M is a dopant ion, most commonly an alkali metal. In this work, the sodium tungsten bronzes (Na x WO3) are investigated as materials for plasmonic applications. The bronzes were fabricated with a solid state reaction, the dielectric function calculated using density functional theory (DFT) and the nanoparticle responses calculated with the boundary element method (BEM). The results were compared to Au and Ag, the materials most widely used in plasmonic applications. It was shown that for x  >  0.5, the solid state fabrication method produces cube-shaped particles of diameter  ⩾1 µm, whose bulk optical properties are well described by a free-electron model and a rigid band structure. The addition of Na into the lattice increases the free electron density, increasing the bulk plasma frequency. Nanoparticle plasmon resonances are found to be highly tunable, and generally at a lower frequency than Au or Ag, and so sodium tungsten bronzes are predicted to be well suited to biomedical or chemical sensing applications.

  3. Characterisation of a Proto-historic bronze collection by micro-EDXRF

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, Elin, E-mail: elin@itn.pt [IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, Estrada Nacional 10, 2686-953 Sacavém (Portugal); CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Araújo, M. Fátima [IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, Estrada Nacional 10, 2686-953 Sacavém (Portugal); Silva, Rui J.C. [CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Vilaça, Raquel [CEAUCP-FCT, Instituto de Arqueologia, Departamento de História, Arqueologia e Artes, Faculdade de Letras, Universidade de Coimbra, Palácio de Sub-Ripas, 3000-395 Coimbra (Portugal)

    2013-02-01

    Highlights: ► A collection of Proto-historic metal artefacts was analysed by micro-EDXRF. ► Composition of major and minor elements has been determined. ► Artefacts were manufactured in a bronze alloy with a low impurity pattern. ► The alloy shows parallels with indigenous Late Bronze Age Iberian productions. -- Abstract: Studies concerning European Proto-historic metallic artefacts can provide important clues about technological transfers during a period of time characterised by diverse cultural interactions. A collection of Proto-historic metallic artefacts from Medronhal (western Iberian Peninsula) composed by rings, bracelets and a fibula related to different cultural affiliations were investigated by micro-EDXRF to provide a major and a minor elemental characterisation. Results show that the Medronhal collection was manufactured in a Cu–Sn alloy (binary bronze) with similar Sn contents among the various types of artefacts and a low impurity pattern. Results of the type and quality of metal were compared to other artefact collections to infer about metallurgical parallels. Strong parallels with indigenous Late Bronze Age Iberian metallurgical productions were found.

  4. Isotopic dietary reconstruction of humans from Middle Bronze Age Lerna, Argolid, Greece

    NARCIS (Netherlands)

    Triantaphyllou, S.; Richards, M. P.; Zerner, C.; Voutsaki, S.

    2008-01-01

    This study presents the results of a carbon and nitrogen stable isotope analysis of 39 human bone and 8 animal samples from Middle Bronze Age (or Middle Helladic, MH, ca. 2100-1700 BC) Lerna, Greece. The isotopic data indicate that the humans had a C-3 terrestrial diet while certain individuals

  5. Antibacterial drugs as corrosion inhibitors for bronze surfaces in acidic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Rotaru, Ileana [Department of Chemical Engineering, “Babes-Bolyai” University, 11 Arany-Janos St., 400028 Cluj-Napoca (Romania); Varvara, Simona, E-mail: svarvara@uab.ro [Department of Exact Sciences and Engineering, “1 Decembrie 1918” University, 11-13 Nicolae Iorga St., 510009 Alba Iulia (Romania); Gaina, Luiza [Department of Chemical Engineering, “Babes-Bolyai” University, 11 Arany-Janos St., 400028 Cluj-Napoca (Romania); Muresan, Liana Maria, E-mail: limur@chem.ubbcluj.ro [Department of Chemical Engineering, “Babes-Bolyai” University, 11 Arany-Janos St., 400028 Cluj-Napoca (Romania)

    2014-12-01

    Graphical abstract: - Highlights: • All four investigated antibacterial drugs act as corrosion inhibitors for bronze surface. • In the presence of antibiotics, a 3RC electric circuit simulates the corrosion system. • The electrochemical results indicate as best inhibitors Doxy, followed by Strepto. • HOMO–LUMO energy gap increases in the order: Doxy > Strepto > Cipro > Amoxi. • The thin protective film on bronze is reinforced by the presence of the antibiotics. - Abstract: The present study is aiming to investigate the effect of four antibiotics (amoxicillin, ciprofloxacin, doxycycline and streptomycin,) belonging to different classes of antibacterial drugs on bronze corrosion in a solution simulating an acid rain (pH 4). Due to their ability to form protective films on the metal surface, the tested antibiotics act as corrosion inhibitors for bronze. The antibiotics were tested at various concentrations in order to determine the optimal concentration range for the best corrosion inhibiting effect. In evaluating the inhibition efficiency, polarization curves, electrochemical impedance spectroscopy, SEM and XPS measurements were used. Moreover, a correlation between the inhibition efficiency of some antibacterial drugs and certain molecular parameters was determined by quantum chemical computations. Parameters like energies E{sub HOMO} and E{sub LUMO} and HOMO–LUMO energy gap were used for correlation with the corrosion data.

  6. Strangers in a strange land: Egyptians in southern Palestine during the Bronze Age

    Directory of Open Access Journals (Sweden)

    Rachael Sparks

    2002-10-01

    Full Text Available When the Institute of Archaeology was formally established in 1937, it became responsible for housing Sir Flinders Petrie’s collection of archaeological material from Palestine. This unique inheritance has great value as a research collection, as its curator demonstrates here in her discussion of interaction between Egypt and Palestine in the Bronze Age.

  7. Genetic variation of the bronze locus (MC1R in turkeys from Southern Brazil

    Directory of Open Access Journals (Sweden)

    Josmael Corso

    2017-03-01

    Full Text Available Abstract Domestic turkeys present several color phenotypes controlled by at least five genetic loci, but only one of these has been identified precisely: the bronze locus, which turned out to be the melanocortin-1 receptor (MC1R gene. MC1R variation is important for breeders interested in maintaining or developing different color varieties. In this study, we sequenced most of the MC1R gene from 16 White Holland (the main commercial turkey variety and 19 pigmented turkeys from southern Brazil with two purposes. The first was to describe the MC1R diversity in White Holland turkeys, which may serve as reservoirs of genetic diversity at this locus. The second was to test whether the traditional color classification used by Brazilian breeders is related to previously known MC1R alleles. White Holland turkeys had four different haplotypes corresponding to the bronze (b+ and black-winged bronze (b1 alleles. Pigmented turkeys also had four haplotypes corresponding to the b+ and b1 alleles, but different haplotypes represent the most common b+ allele in these two groups. The black (B allele was absent from our samples. Overall, our results suggest that white and pigmented individuals form two different populations, and that the traditional color classification used by Brazilian breeders cannot accurately predict the genotypes at the bronze locus.

  8. Genetic variation of the bronze locus (MC1R) in turkeys from Southern Brazil.

    Science.gov (United States)

    Corso, Josmael; Hepp, Diego; Ledur, Mônica C; Peixoto, Jane O; Fagundes, Nelson J R; Freitas, Thales R O

    2017-01-01

    Domestic turkeys present several color phenotypes controlled by at least five genetic loci, but only one of these has been identified precisely: the bronze locus, which turned out to be the melanocortin-1 receptor (MC1R) gene. MC1R variation is important for breeders interested in maintaining or developing different color varieties. In this study, we sequenced most of the MC1R gene from 16 White Holland (the main commercial turkey variety) and 19 pigmented turkeys from southern Brazil with two purposes. The first was to describe the MC1R diversity in White Holland turkeys, which may serve as reservoirs of genetic diversity at this locus. The second was to test whether the traditional color classification used by Brazilian breeders is related to previously known MC1R alleles. White Holland turkeys had four different haplotypes corresponding to the bronze (b+) and black-winged bronze (b1) alleles. Pigmented turkeys also had four haplotypes corresponding to the b+ and b1 alleles, but different haplotypes represent the most common b+ allele in these two groups. The black (B) allele was absent from our samples. Overall, our results suggest that white and pigmented individuals form two different populations, and that the traditional color classification used by Brazilian breeders cannot accurately predict the genotypes at the bronze locus.

  9. Electrodeposition and corrosion resistance of nanocrystalline white bronze (CuSn) coatings

    NARCIS (Netherlands)

    Hovestad, A.; Lekka, M.; Willemsen, R.M.R.; Tacken, R.A.; Bonora, P.L.

    2008-01-01

    For jewellery applications electroplated white bronze (CuSn) was investigated as undercoating for noble metal finishes as alternative to nickel. A strongly acidic plating bath was developed with an organic additive to suppress hydrogen evolution and obtain bright coatings. An electrochemical study

  10. La médaille de bronze du CNRS à un physicien clermontois

    CERN Multimedia

    2005-01-01

    Evey year, the National center for scientific research (CNRS), rewards around fifty of searchers at various stages of their career. The bronze medal rewards the first work of a searcher, making of him a specialist in his field; Philippe Crochet was awarded this medal

  11. Exposition and Synthesis of Benin Bronze Casting: Emphasis on the Olotan Casters of Benin

    Science.gov (United States)

    Ifeta, Chris Funke

    2016-01-01

    The introduction of Western education to Nigeria has brought in its wake great strides toward development. Changes in Benin dates far back to the dawn of the 20th century. This paper investigates the critical role of education in development. The paper integrates interview data collected from bronze casters in Benin. The first section of the paper…

  12. The Agro Pontino region, refuge after the Early Bronze Age Avellino eruption of Mount Vesuvius, Italy?

    NARCIS (Netherlands)

    Bakels, C.; Sevink, J.; Kuijper, W.; Kamermans, H.

    2015-01-01

    In recent years it was discovered that the Middle to Late Holocene infi ll of the Agro Pontino graben (Central Italy) held a tephra layer originating from the Avellino eruption of the Vesuvius volcano. The eruption is dated to 1995 ± 10 calBC and took therefore place during the Early Bronze Age.

  13. Cold Spraying of Cu-Al-Bronze for Cavitation Protection in Marine Environments

    Science.gov (United States)

    Krebs, S.; Gärtner, F.; Klassen, T.

    2015-01-01

    Traveling at high speeds, ships have to face the problem of rudder cavitation-erosion. At present, the problem is countered by fluid dynamically optimized rudders, synthetic, and weld-cladded coatings on steel basis. Nevertheless, docking and repair is required after certain intervals. Bulk Cu-Al-bronzes are in use at ships propellers to withstand corrosion and cavitation. Deposited as coatings with bulk-like properties, such bronzes could also enhance rudder life times. The present study investigates the coating formation by cold spraying CuAl10Fe5Ni5 bronze powders. By calculations of the impact conditions, the range of optimum spray parameters was preselected in terms of the coating quality parameter η on steel substrates with different temperatures. As-atomized and annealed powders were compared to optimize cavitation resistance of the coatings. Results provide insights about the interplay between the mechanical properties of powder and substrate for coating formation. Single particle impact morphologies visualize the deformation behavior. Coating performance was assessed by analyzing microstructures, bond strength, and cavitation resistance. These first results demonstrate that cold-sprayed bronze coatings have a high potential for ensuring a good performances in rudder protection. With further optimization, such coatings could evolve towards a competitive alternative to existing anti-cavitation procedures.

  14. Soft-mode driven tetragonal-to-monoclinic phase transition in multiferroic BiFeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yong; Wang, Kang-Kai; Ni, Li-Hong; Ren, Zhao-Hui; Xu, Gang [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Song, Chen-Lu, E-mail: songcl@zju.edu.cn [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Han, Gao-Rong [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2012-10-01

    The phase transition of BiFeO{sub 3} (BFO) from tetragonal to monoclinic induced by pressure was investigated by first-principles method. The sequential monoclinic phase, M{sub a}, which is favorable during low compression with respect to the tetragonal phase, was characterized. The order parameters were calculated in the vicinity of the phase transition, showing that phase transition has a second-order character. The results demonstrated that the pressure-induced tetragonal-to-monoclinic phase transition in BFO is related to the softening behavior of the E mode, which are very helpful in further investigations of the morphotropic phase boundary (MPB) in lead-free materials. -- Highlights: ► Tetragonal phase BiFeO{sub 3} with fully relaxed structural parameters is dynamically unstable resulting from the softest E phonon. ► Sequence phase of the soft-mode driven phase transition of tetragonal BiFeO{sub 3} is monoclinic (Bm, No. 8). ► The tetragonal-to-monoclinic phase transition occurs at about 13.3 GPa with a second-order character. ► The tetragonal-to-monoclinic phase transition involves the presence of ferroelectric distortion in the a–b plane of BFO.

  15. Critical Commodities: Tracing Greek Trade in Oil and Wine from the Late Bronze Age to the Archaic Period

    OpenAIRE

    Pratt, Catherine Elizabeth

    2014-01-01

    Most studies of the Greek oil and wine industry focus either on the Late Bronze Age or the Classical Period, rarely mentioning the Early Iron Age (so often cast as a Dark Age) between the two. This dissertation attempts to fill this gap by investigating evidence for the continuity of a surplus economy between the Late Bronze Age and the Archaic period. Specifically, I examine what type of oil and wine economy existed in the Late Bronze Age (LBA), how this economy continued into the Early Iron...

  16. An inorganic double helix sheathing alkali metal cations: ANb2P2S12 (A=K, Rb, Cs), a series of thiophosphates close to the metal-nonmetal boundary--chalcogenide analogues of transition-metal phosphate bronzes?

    Science.gov (United States)

    Gieck, Christine; Derstroff, Volkmar; Block, Thomas; Felser, Claudia; Regelsky, Guido; Jepsen, Ove; Ksenofontov, Vadim; Gütlich, Philipp; Eckert, Hellmut; Tremel, Wolfgang

    2004-01-23

    The new quaternary niobium thiophosphates ANb(2)P(2)S(12) (A=K, Rb, Cs) have been prepared and characterized. The title compounds were synthesized by reacting Nb metal, A(2)S, P(2)S(5), and S at 600-700 degrees C in evacuated silica tubes. They crystallize as "stuffed" variants of the tetragonal TaPS(6) structure type in the tetragonal space group I$\\bar 4$2d with eight formula units per unit cell and lattice constants a=15.923(2) and c=13.238(3) A for CsNb(2)P(2)S(12), a=15.887(3) and c=13.132(3) A for RbNb(2)P(2)S(12), and a=15.850(2) and c=13.119(3) A for KNb(2)P(2)S(12). Their structures are based on double helices formed from interpenetrating, noninteracting spiral chains of binuclear [Nb(2)S(12)] cluster units and [PS(4)] thiophosphate groups. The cavities and tunnels, which are formed by the helical chains, are filled with A(+) ions. Temperature-dependent conductivity studies reveal thermally activated electrical transport behavior. This result is consistent with the observation of a temperature-dependent contribution to the (31)P MAS-NMR shift, suggesting that the delocalized s-electron spin density increases with increasing temperature. These findings are supported by the results of tight-binding band structure calculations which reveal that the unusual electrical transport behavior of ANb(2)P(2)S(12) is a consequence of the structure symmetry. Therefore, CsNb(2)P(2)S(12) may be considered a chalcogenide analogue of metal phosphate bronzes.

  17. Ferromagnetism in tetragonally distorted LaCoO3 thin films

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, Virat Vasav; Liberati, Marco; Wong, Franklin J.; Chopdekar, Rajesh Vilas; Arenholz, Elke; Suzuki, Yuri

    2008-09-17

    Thin films of epitaxial LaCoO{sub 3} were synthesized on SrTiO{sub 3} and (La, Sr)(Al, Ta)O{sub 3} substrates varying the oxygen background pressure in order to evaluate the impact of epitaxial growth as well as oxygen vacancies on the long range magnetic order. The epitaxial constraints from the substrate impose a tetragonal distortion compared to the bulk form. X-ray absorption and x-ray magnetic circular dichroism measurements confirmed that the ferromagnetism arises from the Co ions and persists through the entire thickness of the film. It was found that for the thin films to show ferromagnetic order they have to be grown under the higher oxygen pressures, since a decrease in oxygen deposition pressure alters the film structure and suppresses ferromagnetism in the LaCoO{sub 3} films. A correlation of the structure and magnetism suggests that the tetragonal distortions induce the ferromagnetism.

  18. Observation of strain-induced phonon mode splitting in the tetragonal hybrid halide perovskite

    Science.gov (United States)

    Ahn, Hyeyoung; Huang, Hsin; Hsieh, Meng-I.; Li, Ming-Hsien; Chen, Peter

    2017-11-01

    We report the structural and low-frequency vibrational properties of methylammonium lead-iodide (MAPbI3) perovskites studied by terahertz spectroscopy. The characteristic low-frequency mode splitting is observed in room-temperature tetragonal MAPbI3 films grown on Si, and the frequencies of split modes are found to coincide with those of orthorhombic phases. The strain arising from the symmetry and lattice mismatch against the substrates is responsible for the local distortion of inorganic cages and results in the mode-splitting. The use of a mesoporous TiO2 interlayer effectively reduces the strain at the perovskite-substrate interface and induces larger grain growth and the improvement of structural ordering in the tetragonal MAPbI3 films.

  19. Site-Specific Ligand Interactions Favor the Tetragonal Distortion of PbS Nanocrystal Superlattices.

    Science.gov (United States)

    Novák, Jiřı́; Banerjee, Rupak; Kornowski, Andreas; Jankowski, Maciej; André, Alexander; Weller, Horst; Schreiber, Frank; Scheele, Marcus

    2016-08-31

    We analyze the structure and morphology of mesocrystalline, body-centered tetragonal (bct) superlattices of PbS nanocrystals functionalized with oleic acid. On the basis of combined scattering and real space imaging, we derive a three-dimensional (3D) model of the superlattice and show that the bct structure benefits from a balanced combination of {100}PbS-{100}PbS and {111}PbS-{111}PbS interactions between neighboring layers of nanocrystals, which uniquely stabilizes this structure. These interactions are enabled by the coaxial alignment of the atomic lattices of PbS with the superlattice. In addition, we find that this preferential orientation is already weakly present within isolated monolayers. By adding excess oleic acid to the nanocrystal solution, tetragonal distortion is suppressed, and we observe assembly into a bilayered hexagonal lattice reminiscent of a honeycomb with grain sizes of several micrometers.

  20. X-ray Photoelectron Spectroscopy as a tool to investigate silane-based coatings for the protection of outdoor bronze: The role of alloying elements

    Science.gov (United States)

    Masi, G.; Balbo, A.; Esvan, J.; Monticelli, C.; Avila, J.; Robbiola, L.; Bernardi, E.; Bignozzi, M. C.; Asensio, M. C.; Martini, C.; Chiavari, C.

    2018-03-01

    Application of a protective coating is the most widely used conservation treatment for outdoor bronzes (cast Cu-Sn-Zn-Pb-Sb alloys). However, improving coating protectiveness requires detailed knowledge of the coating/substrate chemical bonding. This is particularly the case for 3-mercapto-propyl-trimethoxy-silane (PropS-SH) applied on bronze, exhibiting a good protective behaviour in outdoor simulated conditions. The present work deals with X-Ray Photoelectron Spectroscopy (XPS) and Electron Microscopy (FEG-SEM + FIB (Focused Ion Beam)) characterization of a thin PropS-SH film on bronze. In particular, in order to better understand the influence of alloying elements on coating performance, PropS-SH was studied first on pure Cu and Sn substrates then on bronzes with increasing alloy additions: Cu8Sn as well as a quinary Cu-Sn-Zn-Pb-Sb bronze. Moreover, considering the real application of this coating on historical bronze substrates, previously artificially aged ("patinated") bronze samples were prepared and a comparison between bare and "patinated" quinary bronzes was performed. In the case of coated quinary bronze, the free surface of samples was analysed by High Resolution Photoelectron Spectroscopy using Synchrotron Radiation (HR-SRPES) at ANTARES (Synchrotron SOLEIL), which offers a higher energy and lateral resolution. By compiling complementary spectroscopic and imaging information, a deeper insight into the interactions between the protective coating and the bronze substrate was achieved.

  1. The effects of temperature and NaCl concentration on tetragonal lysozyme face growth rates

    Science.gov (United States)

    Forsythe, Elizabeth; Pusey, Marc Lee

    1994-01-01

    Measurements were made of the (110) and (101) face growth rates of the tetragonal form of hen egg white lysozyme at 0.1M sodium acetate buffer, pH 4.0, from 4 to 22 C and with 3.0%, 5.0%, and 7.0% NaCl used as the precipitating salt. The data were collected at supersaturation ratios ranging from approximately 4 to approximately 63. Both decreasing temperature and increasing salt concentrations shifted plots of the growth rate versus C/C(sat) to the right, i.e. higher supersaturations were required for comparable growth rates. The observed trends in the growth data are counter to those expected from the solubility data. If tetragonal lysozyme crystal growth is by addition of ordered aggregates from the solution, then the observed growth data could be explained as a result of the effects of lowered temperature and increased salt concentration on the kinetics and equilibrium processes governing protein-protein interactions in solution. The data indicate that temperature would be a more tractable means of controlling the growth rate for tetragonal lysozyme crystals contrary to the usual practice in, e.g., vapor diffusion protein crystal growth, where both the precipitant and protein concentrations are simultaneously increased. However, the available range for control is dependent upon the protein concentration, with the greatest growth rate control being at the lower concentration.

  2. Mapping the tetragonal to monoclinic phase transformation in zirconia core dental crowns.

    Science.gov (United States)

    Allahkarami, Masoud; Hanan, Jay C

    2011-12-01

    Chipping failures observed clinically in bilayer systems of porcelain and zirconia restorations should be coupled with a monoclinic to tetragonal phase transformation in the zirconia layer due to the high compressive stress. Phase transformations were mapped using 2D micro X-ray diffraction of 1083 frames at 100μm×100μm spacing automatically positioned along the core layer of a sectioned fractured crown. Yttria-zirconia tetragonal phase transformations to monoclinic zirconia and monoclinic yttria were observed, mostly at the impacted area. A simple map of (101) tetragonal d-spacing strain reveals stress relaxation during phase transformation was detected at inner section of lingual side, because the initial state of compressive residual stress assists this phase transformation at the inter section of lingual side of the core while initial tensile stress at the outer sides under the veneer relaxes under compression and initially prevents phase transformation. This study implements an experimental method to map the phase transformation, after applying local compressive load until fracture. Such fractures resemble clinically observed chipping failure. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  3. Effect of microscale shear stresses on the martensitic phase transformation of nanocrystalline tetragonal zirconia powders

    DEFF Research Database (Denmark)

    Skovgaard, Mette; Ahniyaz, Anwar; Sørensen, Bent F.

    2010-01-01

    For the first time, the effect of microscale shear stress induced by both mechanical compression and ball-milling on the phase stability of nanocrystalline tetragonal zirconia (t-ZrO2) powders was studied in water free, inert atmosphere. It was found that nanocrystalline t-ZrO2 powders are extrem......For the first time, the effect of microscale shear stress induced by both mechanical compression and ball-milling on the phase stability of nanocrystalline tetragonal zirconia (t-ZrO2) powders was studied in water free, inert atmosphere. It was found that nanocrystalline t-ZrO2 powders...... are extremely sensitive to both macroscopic uniaxial compressive strain and ball-milling induced shear stress and easily transform martensitically into the monoclinic phase. A linear relationship between applied compressive stress and the degree of tetragonal to monoclinic (t → m) phase transformation...... was observed. Ball-milling induced microscale stress has a similar effect on the t → m phase transformation. Furthermore, it was found that even very mild milling condition, such as 120 rpm, 1 h (0.5 mm balls) was enough to induce phase transformation. Surfactant assisted ball-milling was found to be very...

  4. The effects of temperature and NaCl concentration on tetragonal lysozyme face growth rates

    Science.gov (United States)

    Forsythe, Elizabeth; Lee Pusey, Marc

    1994-05-01

    Measurements were made of the (110) and (101) face growth rates of the tetragonal form of hen egg white lysozyme at 0.1M sodium acetate buffer, pH 4.0, from 4 to 22°C and with 3.0%, 5.0%, and 7.0% NaCl used as the precipitating salt. The data were collected at supersaturation ratios ranging from ˜4 to ˜63. Both decreasing temperature and increasing salt concentrations shifted plots of the growth rate versus C/ Csat to the right, i.e. higher supersaturations were required for comparable growth rates. The observed trends in the growth data are counter to those expected from the solubility data. If tetragonal lysozyme crystal growth is by addition of ordered aggregates from the solution, then the observed growth data could be explained as a result of the effects of lowered temperature and increased salt concentration on the kinetics and equilibrium processes governing protein-protein interactions in solution. The data indicate that temperature would be a more tractable means of controlling the growth rate for tetragonal lysozyme crystals contrary to the usual practice in, e.g., vapor diffusion protein crystal growth, where both the precipitant and protein concentrations are simultaneously increased. However, the available range for control is dependent upon the protein concentration, with the greatest growth rate control being at the lower concentration.

  5. Preliminary Study of Corrosion Status on Bronzes Excavated from Qin Dynasty Tombs at Xinfeng Town in China

    Directory of Open Access Journals (Sweden)

    Qian-li Fu

    2012-01-01

    Full Text Available From 2007 to 2008, many bronze wares of Qin Dynasty were excavated from tombs at Xinfeng town. Being an important finding, these bronze wares attracted people’s attention, especially for their conservation. Therefore, the corrosive products were explored by using Scanning Electron Microscope with Energy Dispersive X-ray Detector (SEM/EDS, X-Ray diffraction (XRD, and Raman spectroscopy (RM, which provided much valuable information on the conservation of these bronze wares. According to tested results, the corrosive products of bronzes were found to be comprised of cuprite (Cu2O, covellite (CuS, lead carbonate (PbCO3, and malachite (CuCO3·Cu(OH2. Meantime, the multilayer corrosive structure was found in some samples due to the cracks in Cu2O layer which had formed many microchannels to promote the material migration.

  6. Combined effects of graphite and sulfide on the tribological properties of bronze under dry conditions

    Directory of Open Access Journals (Sweden)

    Yoshimasa Hirai

    2016-12-01

    Full Text Available The present study describes the tribological properties of penetrated-graphite bronze containing micro-sized sulfide under dry conditions. The graphite penetration was carried out by means of roller burnishing. Micro shot peening was also applied in order to fabricate micro dimples in the penetrated graphite. The graphite area fraction was approximately 50%. The tribological properties were evaluated using a face-to-face type testing apparatus under dry conditions. The results showed that the friction coefficient of the sulfide-containing bronze decreased and the seizure resistance properties significantly increased. The friction distance until seizure occurrence was improved to more than 2.5 times. Furthermore, the friction coefficient was low and stable until the end of the experiment. It was inferred that the friction resistance was decreased and stabilized when the transfer layer was without Fe content.

  7. Palaeodemographic and palaeopathological characteristics of individuals buried in three Bronze Age sites from southern Croatia

    Directory of Open Access Journals (Sweden)

    M. Novak

    2011-12-01

    Full Text Available The purpose of this study is to reconstruct paleodemographic and paleopathological characteristics of sixteen individuals (three subadults, seven males and six females buried in three Bronze Age sites (Crip, Matkovići, and Veliki Vanik located in southern Croatia. The analysed sample is characterised by the presence of pathological changes which are often associated with stressful episodes such as anaemia, inadequate nutrition, infectious diseases and the occurrence of parasites. Cribra orbitalia, dental enamel hypoplasia, porotic hyperostosis and periostitis were observed in seven out of sixteen analysed skeletons. One ulnar “parry” fracture and three fractures of the frontal bone strongly suggest the presence of deliberate interpersonal violence within the studied communities. The average life span of the adults, as well as the number and character of the observed pathologies, suggest a relatively poor life quality and harsh living conditions in the studied region during the Bronze Age.

  8. Effect of Microstructure on Mechanical Properties of BA1055 Bronze Castings

    Directory of Open Access Journals (Sweden)

    Łabanowski J.

    2014-06-01

    Full Text Available The article presents research results performed on aluminum bronze CuAl10Fe5Ni5 (BA1055 castings used for marine propellers. Metallographic studies were made on light microscope and a scanning electron microscope to assess quantitatively and qualitatively the alloy microstructure. It has been shown that the shape, size and distribution of the iron-rich к−phase precipitates in bronze microstructure significantly affect its mechanical properties. With an increase in the number of small к−phase precipitates increases the tensile strength of castings, while the presence of large globular precipitates improves ductility. Fragmentation and shape of κ−phase precipitates depends on many factors, particularly on the chemical composition of the alloy, Fe/Ni ratio, cooling rate and casting technology.

  9. Connections: the relationships between Neolithic and Bronze Age Megalithic Astronomy in Britain

    CERN Document Server

    Higginbottom, Gail

    2015-01-01

    It has already been empirically verified that for many Bronze Age monuments erected in Scotland between 1400-900 BC, there was a concerted effort on behalf of the builders to align their monuments to astronomical bodies on the horizon. It has also been found that there are two common sets of complex landscape and astronomical patternings, combining specific horizon qualities, like distance and elevation, with the rising and setting points of particular astronomical phenomena. However, it has only been very recently demonstrated by us that that the visible astronomical-landscape variables found at Bronze Age sites on the inner isles and mainland of western Scotland were first established nearly two millennia earlier, with the erection of the mooted first standing-stone 'great circles' in Britain: Callanish and Stenness of Scotland (see G. Higginbottom and R. Clay, The Origins of Standing Stone Astronomy in Britain submitted to Journal of Archaeological Science & available on ArXiv). In the current paper we...

  10. An AMS dated late Bronze Age grave from the mound necropolis at Paulje

    Directory of Open Access Journals (Sweden)

    Gligorić Rada

    2016-01-01

    Full Text Available The subject of the paper is a closed entity - an incineration grave from northwest Serbia, dated to the developed Bronze Age, with an absolute date obtained by AMS (Accelerator mass spectrometry. The sample was taken from the wooden support on which the urn with the bones of the deceased and bronze jewellery was placed. The date obtained corresponds to the 14th century B.C. and confirms earlier proposed suppositions concerning the chronological determination of the necropolises from the territory of Jadar, Podgorina and Lower Podrinje. [Projekat Ministarstva nauke Republike Srbije, br. OI177020: Archaeology of Serbia: cultural identity, integration factors, technological processes and the role of Central Balkans in the development of European prehistory

  11. XRF and micro-PIXE studies of inhomogeneity of ancient bronze and silver alloys

    Science.gov (United States)

    Vasilescu, A.; Constantinescu, B.; Stan, D.; Talmatchi, G.; Ceccato, D.

    2017-09-01

    New results regarding alloy composition and microstructure for a series of ancient bronze and silver items by X-ray Fluorescence and micro-Particle Induced X-ray Emission spectrometry were obtained in the framework of an extensive numismatic project (Scythian-type arrowheads, arrowhead-shaped monetary signs and wheel coins produced by Histria, 7th-4th century of BCE, and Dacian Radulesti-Hunedoara-type silver tetradrachms, 2nd-1st century of BCE). In Histria, warfare arrowheads were used for trade with Barbarian neighbors at first, then mechanically modified, next melted and cast as dedicated monetary signs, being, in the end, replaced by wheel coins. Three different types of alloys have been identified, and Cu-Mn and Cu-Pb segregation shown. In a blank for Radulesti-Hunedoara-type coins, Ag-(Cu+Pb) segregation has been demonstrated, suggesting an imperfectly alloyed silver-leaded bronze.

  12. CHARACTERIZATION OF SHORT E-GLASS FIBER REINFORCEDGRAPHITE AND BRONZE FILLED EPOXY MATRIX COMPOSITES

    Directory of Open Access Journals (Sweden)

    N. Patil

    2016-03-01

    Full Text Available The mechanical characterization of short E- glass fiber reinforced, graphite and sintered bronze filled epoxy composite was carried out in this study. The aim of the present study was to develop tribological engineering material. In this study the flexural strength, theoretical and experimental density, Hardness and Impact strength of composites was investigated experimentally. The results showed that the increased percentage of graphite (10 to 15%Vol and Eglass fiber (10 to 15%Vol enhanced flexural strength (149 MPa of the composite and the maximum flexural modulus (13.3 GPa and 13.1 GPa was obtained for composite C2 and C5 respectively. Maximum hardness (84 on L scale and impact energy (90 Joule was obtained for the composite C6 with increased percentage of glass fiber and graphite filler. The metallurgical electron microscopic images were discussed to interpret the effect of graphite and sintered bronze on mechanical characterization of composite

  13. Cold spraying of aluminum bronze on profiled submillimeter cermet structures formed by laser cladding

    Science.gov (United States)

    Ryashin, N. S.; Malikov, A. G.; Shikalov, V. S.; Gulyaev, I. P.; Kuchumov, B. M.; Klinkov, S. V.; Kosarev, V. F.; Orishich, A. M.

    2017-10-01

    The paper presents results of the cold spraying of aluminum bronze coatings on substrates profiled with WC/Ni tracks obtained by laser cladding. Reinforcing cermet frames shaped as grids with varied mesh sizes were clad on stainless steel substrates using a CO2 laser machine "Siberia" (ITAM SB RAS, Russia). As a result, surfaces/substrates with heterogeneous shape, composition, and mechanical properties were obtained. Aluminum bronze coatings were deposited from 5lF-NS powder (Oerlikon Metco, Switzerland) on those substrates using cold spraying equipment (ITAM SB RAS). Data of profiling, microstructure diagnostics, EDS analysis, and mechanical tests of obtained composites is reported. Surface relief of the sprayed coatings dependence on substrate structure has been demonstrated.

  14. Archaeometallurgical Characterization of Some Ancient Copper and Bronze Artifacts from Albania

    Science.gov (United States)

    Dilo, T.; Civici, N.; Stamati, F.; Cakaj, O.

    2010-01-01

    Ancient copper and bronze artifacts from different Albanian archaeological sites have been analyzed by X-ray-fluorescence analysis to determine the type of alloy and elemental composition and by Optical Microscopy for the investigation of corrosion products and microstructure of the bulk metal. Three bronze coins excavated in Dyrrahu, dating to the IIIrd-IInd century B.C, are composed of copper, tin and lead. Both studied nails, one excavated in Dyrrahu (IVrth-IIIrd century B.C), and the other one found inside an amphora in a ancient ship close to the coast of Saranda (VIth-IVrth century B.C), are composed of copper. The strata-graphical morphology and microstructure images from microscopic examinations allowed us to identify different corrosion products and the diverse stages of metallurgical and mechanical treatment during their manufacture.

  15. Hittites and "barbarians" in the Late Bronze Age: regional survey in northern Turkey

    Directory of Open Access Journals (Sweden)

    Roger Matthews

    1999-11-01

    Full Text Available The Hittites have attracted less attention from British archaeologists than other Bronze Age states of ancient Southwest Asia, and yet in the second millennium BC they controlled most of Anatolia and at the peak of their power they even conquered Babylon. Here the Director of the British Institute of Archaeology at Ankara describes new research on the northwest frontier of the Hittite empire.

  16. Ancient bronze coins from Mediterranean basin: LAMQS potentiality for lead isotopes comparative analysis with former mineral

    Energy Technology Data Exchange (ETDEWEB)

    Torrisi, L., E-mail: Lorenzo.Torrisi@unime.it [Department of Physics Science - MIFT, Messina University, V.le F.S. d’Alcontres 31, 98166 S. Agata, Messina (Italy); Italiano, A. [INFN, Sezione di Catania, Gruppo collegato di Messina (Italy); Torrisi, A. [Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warsaw (Poland)

    2016-11-30

    Highlights: • Surface and bulk compositional elements in ancient bronze coins were investigated using XRF analysis. • Lead stable isotope {sup 204}Pb, {sup 206}Pb, {sup 207}Pb and {sup 208}Pb were measured in ancient coins with LAMQS analysis. • Lead ratios {sup 208}Pb/{sup 206}Pb and {sup 207}Pb/{sup 206}Pb, measured by LAMQS, were compared with Brettscaife.net geological database relative to the minerals in different mines of Mediterranean basin. • Bronze coins were correlated to possible ancient mining sites of minerals from which lead was extracted. - Abstract: Bronze coins coming from the area of the Mediterranean basin, dated back the II–X Cent. A.D., were analyzed using different physical analytical techniques. Characteristic X-ray fluorescence was used with electrons and photons, in order to investigate the elemental composition of both the surface layers and bulk. Moreover, the quadrupole mass spectrometry coupled to laser ablation (LAMQS technique) in high vacuum was used to analyse typical material compounds from surface contamination. Mass spectrometry, at high resolution and sensitivity, extended up to 300 amu, allowed measuring the {sup 208}Pb/{sup 206}Pb and {sup 207}Pb/{sup 206}Pb isotopic ratios into the coins. Quantitative relative analyses of these isotopic ratios identify the coin composition such as a “fingerprint” depending on the mineral used to extract the lead. Isotopic ratios in coins can be compared to those of the possible minerals used to produce the bronze alloy. A comparison between the measured isotope ratios in the analyzed coins and the literature database, related to the mineral containing Pb as a function of its geological and geophysical extraction mine, is presented. The analysis, restricted to old coins and the mines of the Mediterranean basin, indicates a possible correlation between the coin compositions and the possible geological sites of the extracted mineral.

  17. Human paleodiet and animal utilization strategies during the Bronze Age in northwest Yunnan Province, southwest China.

    Directory of Open Access Journals (Sweden)

    Lele Ren

    Full Text Available Reconstructing ancient diets and the use of animals and plants augment our understanding of how humans adapted to different environments. Yunnan Province in southwest China is ecologically and environmentally diverse. During the Neolithic and Bronze Age periods, this region was occupied by a variety of local culture groups with diverse subsistence systems and material culture. In this paper, we obtained carbon (δ13C and nitrogen (δ15N isotopic ratios from human and faunal remains in order to reconstruct human paleodiets and strategies for animal exploitation at the Bronze Age site of Shilinggang (ca. 2500 Cal BP in northwest Yunnan Province. The δ13C results for human samples from Shilinggang demonstrate that people's diets were mainly dominated by C3-based foodstuffs, probably due to both direct consumption of C3 food and as a result of C3 foddering of consumed animals. Auxiliary C4 food signals can also be detected. High δ15N values indicate that meat was an important component of the diet. Analysis of faunal samples indicates that people primarily fed pigs and dogs with human food waste, while sheep/goats and cattle were foddered with other food sources. We compare stable isotope and archaeobotanical data from Shilinggang with data from other Bronze Age sites in Yunnan to explore potential regional variation in subsistence strategies. Our work suggests that people adopted different animal utilization and subsistence strategies in different parts of Yunnan during the Bronze Age period, probably as local adaptations to the highly diversified and isolated environments in the region.

  18. Neolithic and Bronze Age migration to Ireland and establishment of the insular Atlantic genome.

    Science.gov (United States)

    Cassidy, Lara M; Martiniano, Rui; Murphy, Eileen M; Teasdale, Matthew D; Mallory, James; Hartwell, Barrie; Bradley, Daniel G

    2016-01-12

    The Neolithic and Bronze Age transitions were profound cultural shifts catalyzed in parts of Europe by migrations, first of early farmers from the Near East and then Bronze Age herders from the Pontic Steppe. However, a decades-long, unresolved controversy is whether population change or cultural adoption occurred at the Atlantic edge, within the British Isles. We address this issue by using the first whole genome data from prehistoric Irish individuals. A Neolithic woman (3343-3020 cal BC) from a megalithic burial (10.3× coverage) possessed a genome of predominantly Near Eastern origin. She had some hunter-gatherer ancestry but belonged to a population of large effective size, suggesting a substantial influx of early farmers to the island. Three Bronze Age individuals from Rathlin Island (2026-1534 cal BC), including one high coverage (10.5×) genome, showed substantial Steppe genetic heritage indicating that the European population upheavals of the third millennium manifested all of the way from southern Siberia to the western ocean. This turnover invites the possibility of accompanying introduction of Indo-European, perhaps early Celtic, language. Irish Bronze Age haplotypic similarity is strongest within modern Irish, Scottish, and Welsh populations, and several important genetic variants that today show maximal or very high frequencies in Ireland appear at this horizon. These include those coding for lactase persistence, blue eye color, Y chromosome R1b haplotypes, and the hemochromatosis C282Y allele; to our knowledge, the first detection of a known Mendelian disease variant in prehistory. These findings together suggest the establishment of central attributes of the Irish genome 4,000 y ago.

  19. Friction stir processing of nickel aluminum propeller bronze in comparison to fusion welds

    OpenAIRE

    Murray, David L.

    2005-01-01

    Friction Stir Processing (FSP) is currently being considered for use in manufacture of the Navy's NiAl bronze propellers. Incorporating this technology may improve service performance and enable reduction of manufacturing time and cost. This program of research has employed miniature tensile sample designs to examine the distributions of longitudinal properties through the various regimes in a fusion weld. Also, the distributions of both longitudinal and transverse properties throughout t...

  20. Middle and Late Bronze Age settlement on the South Downs: the case study of Black Patch

    OpenAIRE

    Tapper, Richard Quinn

    2012-01-01

    By integrating the corpus of existing knowledge with new information gained by applying geo-archaeological techniques as well as more traditional techniques to fresh archaeological investigations at Black Patch and elsewhere, the aims of the research are to look at the economy, social organization and ritual behaviour of life in the Middle and Late Bronze Age on the South Downs in the light of modern archaeological theory to consider the questions ‘Why were these areas chosen for settlement?’...

  1. Compositional analyses of a Reutlingen Bronze Age sword discovered at Giurgiu, Romania

    OpenAIRE

    Olariu, Agata; Alexandrescu, Emilian; Avram, Alexandru; Badica, Teodor

    2003-01-01

    The compositional scheme of a Bronze Age sword, found near the town of Giurgiu in Romania has been determined by the method of particle-induced X-ray emission (PIXE), at the tandem accelerator of the National Institute for Physics and Nuclear Engineering from Bucharest, Magurele, Romania. The results of the analyses and the comparison with the composition of other swords from the same geographic area, the Danubian plane from Bulgaria and Transylvania regions, show that the sword from Giurgiu ...

  2. Journey to murder. Atypical graves of immigrants in the Early Bronze Age Europe.

    OpenAIRE

    Pokutta, Dalia

    2014-01-01

    Migrations had important effects on Bronze Age economy, adaptation of new inventions and technological cohesion, however their impact upon society remains under-studied. The knowledge of how individual longdistance mobility affected various forms of societal interaction is limited and fragmented, especially when it comes to murder. In archaeology the analyses of criminality encounter massive obstacles due to unknowable character of crimes, victims and social contexts of these. In this paper w...

  3. Fast polarization mechanisms in the uniaxial tungsten-bronze relaxor strontium barium niobate SBN-81

    Czech Academy of Sciences Publication Activity Database

    Buixaderas, Elena; Kadlec, Christelle; Kempa, Martin; Bovtun, Viktor; Savinov, Maxim; Bednyakov, Petr; Hlinka, Jiří; Dec, J.

    2017-01-01

    Roč. 7, Dec (2017), s. 1-11, č. článku 18034. ISSN 2045-2322 R&D Projects: GA ČR GA16-09142S; GA MŠk(CZ) LD15014 Institutional support: RVO:68378271 Keywords : relaxor * tungsten-bronzes * dielectric response * phonons * broad-band spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.259, year: 2016

  4. Characterisation of artificial patinas on bronze sculptures of the Carlo Bilotti Museum (Rome)

    Science.gov (United States)

    Casanova Municchia, A.; Bellatreccia, F.; D'Ercoli, G.; Lo Mastro, S.; Reho, I.; Ricci, M. A.; Sodo, A.

    2016-12-01

    Two bronze sculptures, Ettore e Andromaca, a reproduction of a plaster model by Giorgio de Chirico, and Cardinale, a cast made from an original by Giacomo Manzù, stand outside the Carlo Bilotti contemporary art museum in Villa Borghese park (Rome). The composition of the artificial brown patina present on the statues' surface, which was applied for aesthetic purposes, is unknown. This paper reports analysis carried out to identify the composition of the artificial patina and describe the corrosion products formed in outdoor conditions. Raman spectroscopy and scanning electron microscopy equipped with X-ray microanalysis were performed on sample fragments and powder scrapings taken from the bronze statues. X-ray powder diffraction was used whenever possible and subject to conservation priorities. Our data revealed, in the artificial brown patina, the formation of copper oxides (cuprite and tenorite) on the surface of both sculptures as possible result of oxidisation treatments performed with a blowtorch before the artificial patination process began. Furthermore, a copper nitrate (gerhardtite) was identified as an ingredient in the preparation applied to the bronze surfaces. The green areas revealed the presence of corrosion products as copper sulphate hydroxide (brochantite) and copper sulphate-chloride (connellite), which form under acid rains conditions.

  5. Analysis of the Quintilii’s Villa Bronzes by Spectroscopy Techniques

    Directory of Open Access Journals (Sweden)

    Fabio Stranges

    2014-01-01

    Full Text Available The aim of this work is the characterization, with different diagnostic tests, of three fragments of bronze artefacts recovered from the Villa of the Quintilii (located in the south of Rome. In particular, the sample alloys were investigated by different chemical and morphological analysis. Firstly, an analysis of the alloy, implemented through the electronic spectroscopy, was taken to discriminate the bronze morphology and its elemental composition. Subsequently, a surface analysis was realized by molecular spectroscopy to identify the alteration patinas on surfaces (such as bronze disease. Two diagnostic techniques are used for the alloy analysis: scanning electron microscopy (SEM connected to the EDX spectroscopy (to study the morphology and alloy composition and Auger electron spectroscopy (AES (to identify the oxidation state of each element. Moreover, for the study of surface patinas, IR and Raman spectroscopies were implemented. All studies were performed on the “as received” samples, covered by a thin layer of excavated soil and on samples processed in an aqueous solution of sulphuric acid (10%, to remove patinas and alterations.

  6. Improvement of viscoelastic damping in nickel aluminum bronze by indium-tin

    Science.gov (United States)

    Lee, Taeyong

    2011-06-01

    Reduction of the vibration noise from submarine propellers is of interest in naval operations. Such an objective can be achieved via the use of materials with the ability to dissipate energy of vibration by means of heat, i.e. high damping materials. An additional problem is that the extreme hydrostatic pressure environment of a submarine requires the chosen material to exhibit considerably high stiffness. Most materials demonstrate a compromise between the two properties, i.e. stiffness and damping. This paper aims to discuss research into high stiffness and high damping materials conducted using a dynamic mechanical analyzer (DMA) under variations of testing temperature, frequency, and strain amplitude. Alloys of nickel aluminum bronze and indium tin are the subjects of this study. Defect damping represents a large portion of the overall damping properties of the nickel aluminum bronze while increasing indium content is shown to boost the damping properties of the indium tin alloy. The study then continues with the development of a new material that combines both indium alloying and defects introduction into the nickel aluminum bronze alloy. The new alloy is observed to have high damping, as measured in its high tan δ, with minimum reduction of the stiffness | E*|.

  7. Evaluation of the inhibitive effect of benzotriazole on archeological bronze in acidic medium

    Science.gov (United States)

    Hassairi, Hèla; Bousselmi, Latifa; Khosrof, Slim; Triki, Ezzeddine

    2013-12-01

    An archaeological bronze artefact was a Punic coin excavated from the north east of Tunisia in 2001. The composition of the copper alloy revealed a content of 3.5 % of tin and 1.4 % of lead with the presence of some sulphur heterogeneity. The surface presents some roughnesses and cracks and is covered by a corrosion layer of 20-40 μm thickness. The use of benzotriazole (BTA) as an inhibitor has become a standard element for the preservation of cuprous-based metals. In order to investigate the behaviour of BTA in an acidic medium, an Electrochemical Impedance Spectroscopy (EIS) investigation was performed to characterize the electrochemical behaviour of the interface of the archaeological bronze sample/acidic medium without and with BTA addition. Impedance diagrams obtained at different immersion times show that the presence of the inhibitor prevents the diffusional process observed in the absence of BTA. The inhibition of the pre-polarized bronze surface revealed that the mechanism of action of the benzotriazole molecule in an acidic medium is governed by the chemisorption process.

  8. Feeding and Cooling and Time of Thermal Treatment of a Massive Bush Made of the Complex Aluminum Bronze Cast by the Lost Foam

    Directory of Open Access Journals (Sweden)

    Just P.

    2014-12-01

    Full Text Available Small additions of Cr, Mo and W to aluminium-iron-nickel bronze are mostly located in phases κi (i=II; III; IV,and next in phase α (in the matrix and phase γ2. They raise the temperature of the phase transformations in aluminium bronzes as well as the casts’ abrasive and adhesive wear resistance. The paper presents a selection of feeding elements and thermal treatment times which guarantees structure stability, for a cast of a massive bush working at an elevated temperature (650-750°C made by means of the lost foam technology out of composite aluminium bronze. So far, there have been no analyses of the phenomena characteristic to the examined bronze which accompany the process of its solidification during gasification of the EPS pattern. There are also no guidelines for designing risers and steel internal chill for casts made of this bronze. The work identifies the type and location of the existing defects in the mould’s cast. It also proposes a solution to the manner of its feeding and cooling which compensates the significant volume contraction of bronze and effectively removes the formed gases from the area of mould solidification. Another important aspect of the performed research was establishing the duration time of bronze annealing at the temperature of 750°C which guarantees stabilization of the changes in the bronze microstructure - stabilization of the changes in the bronze HB hardness.

  9. A systematic approach to Bronze corrosion products and the methods of treatment , applied on three bronze anklets from Dhamar museum , Yemen

    Directory of Open Access Journals (Sweden)

    Hazem Mohamed

    2014-04-01

    Full Text Available Three bronze anklets were found during the archaeological excavation of Yemeni mission 2002 A.D, in Gabal al- lawd , Jawf area , Yemen , they dated back to Minaean period in Yemen [sixth century B.C – 24 B.C] , and now they are situated in Dhamar regional museum .They were suffered from the deterioration aspects , two of these anklets had a thick corrosion products of pale green / brown , the third anklet had a rust-colored Black and Brown with the presence of small parts and scattered pale green. The aim of this paper is to examine, in detail, the corrosion of the selected objects that was grown during the long-term burial and identify its products that will help us to understand the corrosive factors and the degradation mechanisms , as well as their constituting metals in order to carry out scientific treatment and conservation .For this purpose ,samples from the objects were examined by Metallographic Microscope (ME , Scanning Electron Microscope (SEM, the corrosion products were analyzed by X-ray diffraction (XRD and X-ray fluorescence( XRF was used to determine the objects metallic constituents . XRD data showed that the corrosion products constitute of cuprite , atacamite , and paratacamite , whereas XRF analysis declared that the anklets compose of bronze alloy . Microscopic examination reveals that the three anklets were suffered from the deterioration spots , which dispersed on the metal surface . Chemical cleaning was chosen for treating the objects , finally they were isolated to preserve them against further attack.

  10. Variational method of determining effective moduli of polycrystals with tetragonal symmetry

    Science.gov (United States)

    Meister, R.; Peselnick, L.

    1966-01-01

    Variational principles have been applied to aggregates of randomly oriented pure-phase polycrystals having tetragonal symmetry. The bounds of the effective elastic moduli obtained in this way show a substantial improvement over the bounds obtained by means of the Voigt and Reuss assumptions. The Hill average is found to be a good approximation in most cases when compared to the bounds found from the variational method. The new bounds reduce in their limits to the Voigt and Reuss values. ?? 1966 The American Institute of Physics.

  11. First-principles comparison of the cubic and tetragonal phases of Mo3Sb7

    KAUST Repository

    Nazir, Safdar

    2011-03-01

    Using ab initio density functional based methods, we study the normal metal state properties of the ∼3 K Mo3Sb7 superconductor, in its high temperature cubic and low temperature tetragonal structures. Although the density of states at the Fermi energy is reasonably high in both structures, our calculations unequivocally show that there exists no long range magnetic ordering in this system. We also address the optical properties of the compound. The magnetism in Mo3Sb7 is studied by fixed spin moment calculations, which yield a shallow non-magnetic minimum, thus inferring propensity to a magnetic instability. © 2011 Elsevier B.V. All rights reserved.

  12. Alumina reinforced tetragonal zirconia (TZP) composites. Final technical report, July 1, 1993--December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Shetty, D.K.

    1997-06-01

    This final technical report summarizes the significant research results obtained during the period July 1, 1993 through December 31, 1996 in the DOE-supported research project entitled, {open_quotes}Alumina Reinforced Tetragonal Zirconia (TZP) Composites{close_quotes}. The objective of the research was to develop high-strength and high-toughness ceramic composites by combining mechanisms of platelet, whisker or fiber reinforcement with transformation toughening. The approach used included reinforcement of Celia- or yttria-partially-stabilized zirconia (Ce-TZP or Y-TZP) with particulates, platelets, or continuous filaments of alumina.

  13. Corrosion investigation of fire-gilded bronze involving high surface resolution spectroscopic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Masi, G., E-mail: giulia.masi5@unibo.it [Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Università di Bologna, via Terracini 28, 40131 Bologna (Italy); Chiavari, C., E-mail: cristina.chiavari@unibo.it [Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Università di Bologna, via Terracini 28, 40131 Bologna (Italy); C.I.R.I. (Centro Interdipartimentale Ricerca Industriale) Meccanica Avanzata e Materiali, Università di Bologna, Bologna, via Terracini 28, 40131 Bologna (Italy); Avila, J., E-mail: jose.avila@synchrotron-soleil.fr [Synchrotron SOLEIL, L’Orme des Merisiers, 91190 Saint-Aubin (France); Esvan, J., E-mail: jerome.esvan@ensiacet.fr [Centre Interuniversitaire de Recherche et d’Ingénierie des Matériaux, Université de Toulouse, 4 allée Emile Monso, 31030 Toulouse (France); Raffo, S., E-mail: simona.raffo2@unibo.it [Dipartimento di Chimica Industriale “Toso Montanari”, Università di Bologna, viale Risorgimento 4, 40136 Bologna (Italy); Bignozzi, M.C., E-mail: maria.bignozzi@unibo.it [Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Università di Bologna, via Terracini 28, 40131 Bologna (Italy); Asensio, M.C., E-mail: maria-carmen.asensio@synchrotron-soleil.fr [Synchrotron SOLEIL, L’Orme des Merisiers, 91190 Saint-Aubin (France); Robbiola, L., E-mail: robbiola@univ-tlse2.fr [TRACES Lab (CNRS UMR5608), Université Toulouse Jean-Jaurès, 5, allées Antonio-Machado, 31058 Toulouse (France); and others

    2016-03-15

    Graphical abstract: - Highlights: • Fire-gilded bronze prepared by ancient methods (Au–Hg layer on Cu–Sn–Zn–Pb–Sb). • Heating during gilding induces Sn and Znenrichment in the top part of the gilded layer. • SR-HRPES mapping of corrosion craters (cross-section) after accelerated ageing. • Selective dissolution of Cu and Zn in the craters induces Sn species enrichment. • The main species in the craters are related to hydroxi-oxide compounds. - Abstract: Gilded bronzes are often affected by severe corrosion, due to defects in the Au layer and Au/Cu alloy galvanic coupling, stimulated by large cathodic area of the gilded layer. Galvanic corrosion, triggered by gilding defects, leads to products growth at the Au/bronze interface, inducing blistering or break-up of the Au layer. In this context, fire-gilded bronze replicas prepared by ancient methods (use of spreadable Au–Hg paste) was specifically characterised by compiling complementary spectroscopic and imaging information before/after accelerated ageing with synthetic rain. Fire-gilded bronze samples were chemically imaged in cross-section at nano-metric scale (<200 nm) using high energy and lateral resolution synchrotron radiation photoemission (HR-SRPES) of core levels and valence band after conventional characterisation of the samples by Glow Discharge optical Emission Spectroscopy (GD-OES) and conventional X-ray photoelectron spectroscopy (XPS). We have found a net surface enrichment in Zn and Sn after fire-gilding and presence of metallic Hg, Pb and Cu within the Au layer. Moreover, the composition distribution of the elements together with their oxidation has been determined. It was also revealed that metallic phases including Hg and Pb remain in the gilding after corrosion. Moreover, selective dissolution of Zn and Cu occurs in the crater due to galvanic coupling, which locally induces relative Sn species enrichment (decuprification). The feasibility advantages and disadvantages of

  14. Zircônia tetragonal policristalina. Parte II: Microestrutura e resistividade elétrica Tetragonal zirconia polycrystals. Part II: Microstructure and electrical resistivity

    Directory of Open Access Journals (Sweden)

    S. K. Tadokoro

    2001-06-01

    Full Text Available Nesta segunda parte são mostrados os resultados obtidos em cerâmicas densas de ZrO2: 3% mol Y2O3 (Y-TZP e 12% mol CeO2 (Ce-TZP, analisadas por espectroscopia Raman, microscopia eletrônica de varredura, e por espectroscopia de impedância. Os resultados mostram que, para ambos tipos de amostras, é possível obter cerâmicas densas (> 95% da densidade teórica para temperaturas de sinterização inferiores a 0,45 T F (T F = temperatura de fusão. A taxa de crescimento de grãos é dependente do cátion estabilizante, sendo maior para a Ce-TZP do que para a Y-TZP. Os espectros Raman de cerâmicas sinterizadas mostram as bandas típicas associadas aos modos ativos da fase cristalográfica tetragonal. Os resultados de espectroscopia de impedância são similares aos obtidos por outros pesquisadores tanto para cerâmicas convencionais quanto nanofásicas no caso da Y-TZP. Para a Ce-TZP foi observada uma redução na condutividade extrínseca em conseqüência da maior pureza do precursor cristalizado.Results on dense ZrO2: 3 mol% Y2O3 (Y-TZP and 12 mol% CeO2 (Ce-TZP ceramics are shown in this second part. Sintered specimens were analyzed by Raman spectroscopy, scanning electron microscopy and impedance spectroscopy. The main results show that both types of solid solutions may attain a high densification (> 95% of the theoretical density for sintering temperatures lower than 0.45 T F (T F = melting temperature. The rate of grain growth is governed by the stabilizing cation and is faster for Ce-TZP than for Y-TZP. Raman spectra exhibit the six characteristic bands of the tetragonal phase for both specimens. Impedance spectroscopy results for Y-TZP do not differ from those obtained for nanophase ceramics. A reduction in the extrinsic conductivity due to the high purity of the crystallized precursor was observed for Ce-TZP specimens.

  15. Atomic Origins of Monoclinic-Tetragonal (Rutile) Phase Transition in Doped VO 2 Nanowires

    KAUST Repository

    Asayesh-Ardakani, Hasti

    2015-10-12

    There has been long-standing interest in tuning the metal-insulator phase transition in vanadium dioxide (VO) via the addition of chemical dopants. However, the underlying mechanisms by which doping elements regulate the phase transition in VO are poorly understood. Taking advantage of aberration-corrected scanning transmission electron microscopy, we reveal the atomistic origins by which tungsten (W) dopants influence the phase transition in single crystalline WVO nanowires. Our atomically resolved strain maps clearly show the localized strain normal to the (122¯) lattice planes of the low W-doped monoclinic structure (insulator). These strain maps demonstrate how anisotropic localized stress created by dopants in the monoclinic structure accelerates the phase transition and lead to relaxation of structure in tetragonal form. In contrast, the strain distribution in the high W-doped VO structure is relatively uniform as a result of transition to tetragonal (metallic) phase. The directional strain gradients are furthermore corroborated by density functional theory calculations that show the energetic consequences of distortions to the local structure. These findings pave the roadmap for lattice-stress engineering of the MIT behavior in strongly correlated materials for specific applications such as ultrafast electronic switches and electro-optical sensors.

  16. Internal stresses and stability of the tetragonal phase in zirconia thin layers deposited by OMCVD

    Energy Technology Data Exchange (ETDEWEB)

    Benali, B.; Huntz, A.M. [University Paris-Sud, LEMHE-ICMMO, CNRS-UMR 8182, Bat. 410, F-91405 ORSAY Cedex (France); Andrieux, M. [University Paris-Sud, LEMHE-ICMMO, CNRS-UMR 8182, Bat. 410, F-91405 ORSAY Cedex (France)], E-mail: michel.andrieux@u-psud.fr; Ignat, M. [Laboratoire de Thermodynamique et Physico-Chimie Metallurgiques, LTPCM, INPG-ENSEEG, CNRS UMR 5614, F-38402 Saint Martin d' Heres (France); Poissonnet, S. [DEN/DANS/DMN/SRMP, CEA Saclay, F-91191 Gif/Yvette (France)

    2008-07-15

    Zirconia thin films were deposited by OMCVD (organo-metallic chemical vapour deposition) at various temperatures and oxygen partial pressures on a AISI 301 stainless steel substrate with Zr(thd){sub 4} as precursor. The as deposited 250 nm thin zirconia films presented a structure consisting of two phases: the expected monoclinic one and also an unexpected tetragonal phase. According to the literature, the stabilization of the tetragonal phase (metastable in massive zirconia) can be related to the crystallite size and/or to the generated internal compressive stresses. To analyze the effect of internal and external stresses on the thin film behaviour, in-situ tensile experiments were performed at room temperature and at high temperature (500 deg. C). Depending on the process parameters, phase transformations and damage evolution of the films were observed. Our results, associated to XRD (X-ray diffraction) analyses, used to determine phase ratios and residual stresses within the films, before and after the mechanical experiments, are discussed with respect to their microstructural changes.

  17. AFM Studies of Salt Concentration Effects on the (110) Surface Structure of Tetragonal Lysozyme Crystals

    Science.gov (United States)

    Pusey, Marc Lee; Gorti, Sridhar; Forsythe, Elizabeth; Konnert, John

    2002-01-01

    Previous high resolution AFM studies of the (110) surface of tetragonal chicken egg white lysozyme crystals had shown that only one of two possible molecular surfaces is present, those constituting the completed 43 helices. These suggested that the crystal growth process was by the solution-phase assembly of the growth units, which then attach to the surface. However, the best fit for the imaged surfaces, vs. those predicted based upon the bulk crystallographic coordinates, were obtained when the packing about the 43 helices was "tightened up", while maintaining the underlying crystallographic unit cell spacing. This results in a widening of the gap between adjacent helices, and the top- most layer(s) may no longer be in contact. We postulated that the tightened packing about the helices is a result of the high salt concentrations in the bulk solution, used to crystallize the protein, driving hydrophobic interactions. Once the crystal surface is sufficiently buried by subsequent growth layers the ratio of salt to protein molecules decreases and the helices relax to their bulk crystallographic coordinates. The crystal surface helix structure is thus a reflection of the solution structure, and the tightness of the packing about the 43 helices would be a function of the bulk salt concentration. AFM images of the (110) surface of tetragonal lysozyme crystals grown under low (2%) and high (5%) NaCl concentrations reveal differences in the packing about the 43 helices consistent with the above proposal.

  18. {sup 14}C dating of the Early to Late Bronze Age stratigraphic sequence of Aegina Kolonna, Greece

    Energy Technology Data Exchange (ETDEWEB)

    Wild, E.M., E-mail: Eva.Maria.Wild@univie.ac.a [VERA Laboratory, Faculty of Physics - Isotope Research, University of Vienna, Waehringer Strasse 17, A-1090 Wien (Austria); Gauss, W. [Austrian Archaeological Institute at Athens, Leof. Alexandras 26, Gr10683 Athens (Greece); Forstenpointner, G. [University of Veterinary Medicine Vienna, Dept. of Pathobiology, Institute of Anatomy, Unit on Archaeozoology and Comparative Morphology, Veterinaerplatz 1, A-1210 Vienna (Austria); Lindblom, M. [Dept. of Archaeology and Ancient History Uppsala, University Box 626, SE-751 26 Uppsala (Sweden); Smetana, R. [Altertumswissenschaften, University of Salzburg, Residenzplatz 1/I, A-5020 Salzburg (Austria); Steier, P. [VERA Laboratory, Faculty of Physics - Isotope Research, University of Vienna, Waehringer Strasse 17, A-1090 Wien (Austria); Thanheiser, U. [Vienna Institute for Archaeological Science (VIAS), Althanstrasse 14, A-1090 Vienna (Austria); Weninger, F. [VERA Laboratory, Faculty of Physics - Isotope Research, University of Vienna, Waehringer Strasse 17, A-1090 Wien (Austria)

    2010-04-15

    Aegina Kolonna, located in the center of the Saronic Gulf in the Aegean Mediterranean (Greece), is one of the major archaeological sites of the Aegean Bronze Age with a continuous stratigraphic settlement sequence from the Late Neolithic to the Late Bronze Age. Due to its position next to the maritime cross roads between central mainland Greece, the northeast Peloponnese, the Cyclades and Crete, the island played an important role in the trade between these regions. In the course of new excavations, which focused on the exploration of the Early, Middle and Late Bronze Age at Kolonna, several short lived samples from different settlement phases have been {sup 14}C-dated with the AMS method at the VERA laboratory. Bayesian sequencing of the {sup 14}C data according to the stratigraphic position of the samples in the profile was performed to enable estimates of the transition time between the cultural phases. The Aegina Kolonna {sup 14}C sequence is one of the longest existing so far for the Aegean Bronze Age, and therefore of major importance for the absolute Bronze Age chronology in this region. Preliminary results indicate that the Middle Helladic period seems to have started earlier and lasted longer than traditionally assumed. Further, at the present stage of our investigation we can give also a very tentative time frame for the Santorini volcanic eruption which seems to be in agreement with the science derived VDL date.

  19. Transition to collapsed tetragonal phase in CaFe2As2 single crystals as seen by 57Fe Mössbauer spectroscopy

    Science.gov (United States)

    Bud'ko, Sergey L.; Ma, Xiaoming; Tomić, Milan; Ran, Sheng; Valentí, Roser; Canfield, Paul C.

    2016-01-01

    Temperature dependent measurements of 57Fe Mössbauer spectra on CaFe2As2 single crystals in the tetragonal and collapsed tetragonal phases are reported. Clear features in the temperature dependencies of the isomer shift, relative spectra area, and quadrupole splitting are observed at the transition from the tetragonal to the collapsed tetragonal phase. From the temperature dependent isomer shift and spectral area data, an average stiffening of the phonon modes in the collapsed tetragonal phase is inferred. The quadrupole splitting increases by ˜25 % on cooling from room temperature to ˜100 K in the tetragonal phase and is only weakly temperature dependent at low temperatures in the collapsed tetragonal phase, in agreement with the anisotropic thermal expansion in this material. In order to gain microscopic insight about these measurements, we perform ab initio density functional theory calculations of the electric field gradient and the electron density of CaFe2As2 in both phases. By comparing the experimental data with the calculations we are able to fully characterize the crystal structure of the samples in the collapsed-tetragonal phase through determination of the As z coordinate. Based on the obtained temperature dependent structural data we are able to propose charge saturation of the Fe-As bond region as the mechanism behind the stabilization of the collapsed-tetragonal phase at ambient pressure.

  20. Phase Transitions and Domain Structure in Mixed Tetragonal-Rhombohedral BiFeO3 thin films using Raman Spectroscopy and Nonlinear Optics

    Science.gov (United States)

    Vlahos, E.; Kumar, A.; Denev, S.; Melville, A.; Adamo, C.; Ihlefeld, J. F.; Sheng, G.; Zeches, R. J.; Zhang, J. X.; He, Q.; Yang, C. H.; Erni, R.; Rossell, M. D.; J, A.; Hatt; Chu, Y.-H.; Wang, C. H.; Ederer, C.; Gopalan, V.; Chen, L. Q.; Schlom, D. G.; Spaldin, N. A.; Martin, L. W.; Ramesh, R.; Tenne, Dmitri

    2010-03-01

    We have shown that biaxially strained BiFeO3 thin films can undergo an isosymmetric phase transition from a rhombohedral-like to a tetragonal-like phase. This talk discusses the evolution of the tetragonal and the mixed phases in BiFeO3/YAlO3 thin films with varying film thickness using optical second harmonic generation (SHG) and Raman spectroscopy. 25nm, 75nm, and 225 nm thick films were studied; thinner films are dominated by the tetragonal phase, whereas thicker films exhibit both tetragonal and rhombohedral phases. The evolution of these phases as function of film thickness and temperature was experimentally determined.

  1. Tetragonal lattice collapse in SrFe{sub 2}As{sub 2} - a combined experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, Miriam; Kasinathan, Deepa; Omerci, Alim; Meier, Katrin; Schwarz, Ulrich; Grin, Yuri; Leithe-Jasper, Andreas; Rosner, Helge [MPI, CPfS, Dresden (Germany); Hanfland, Michael [ESRF, Grenoble (France); Koepernik, Klaus [IFW, Dresden (Germany)

    2011-07-01

    In a joint experimental and theoretical study we investigate the crystal structure of the Fe pnictide compounds SrFe{sub 2}As{sub 2} under applied hydrostatic pressure. Applying high pressure X-ray diffraction, for a critical pressure of about 10 GPa we observe a sudden collapse of the tetragonal c axis, accompanied by a small expansion of the basal plane. This results in a drastic reduction of the c/a ratio and a significant decrease of the unit cell volume. This tetragonal collapse is well described by DFT band structure calculations and can be assigned to the formation of an additional As-As bond along the tetragonal c axis.

  2. Correlation between tetragonal zinc-blende structure and magnetocrystalline anisotropy of MnGa epilayers on GaAs(111)

    Science.gov (United States)

    Arins, A. W.; Jurca, H. F.; Zarpellon, J.; Fabrim, Z. E.; Fichtner, P. F. P.; Varalda, J.; Schreiner, W. H.; Mosca, D. H.

    2015-05-01

    MnGa films of few nanometer thickness with tetragonal zinc-blende (TZB) structure were grown by molecular beam epitaxy on GaAs(111) substrates. These ultrathin films have high magnetization at room temperature with magnetic moment as high as 3.2 μB per formula unit. A strong magnetocrystalline anisotropy energy (MAE) comparable to that reported to δ-MnGa films with body-centered tetragonal (BCT) structure with similar c/a=1.1 is observed. Electronic structure calculations using density functional theory (DFT) reveal a robust ferrimagnetic ground state at room temperature and confirm that zinc-blende structure with tetragonal distortion has a metastable character. The strong MAE is associated with anisotropy of orbital magnetic moment which is described by the symmetry of the spin-polarized charge density along the crystallographic axes.

  3. Pioneering farmers cultivating new lands in the North – The expansion of agrarian societies during the Neolithic and Bronze Age in Scandinavia

    DEFF Research Database (Denmark)

    Sørensen, Lasse

    2012-01-01

    Pioneering farmers cultivating new lands in the North – The expansion of agrarian societies during the Neolithic and Bronze Age in Scandinavia......Pioneering farmers cultivating new lands in the North – The expansion of agrarian societies during the Neolithic and Bronze Age in Scandinavia...

  4. Depth resolved domain mapping in tetragonal SrTiO{sub 3} by micro-Laue diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Merz, T. A., E-mail: tmerz@stanford.edu; Inoue, H. [Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Noad, H.; Hikita, Y.; Vailionis, A.; Moler, K. A.; Hwang, H. Y. [Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Xu, R.; Liu, W. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2016-05-02

    We present depth resolved X-ray micro-Laue diffraction experiments on the low temperature domain structure of SrTiO{sub 3}. At 80 K, monochromatic X-ray diffraction shows an elongated out-of-plane unit cell axis within a matrix of in-plane oriented tetragonal unit cells. Full deviatoric strain mappings from white beam diffraction show a dominance of two tetragonal domain orientations (x- and z-axes) over a large area of sample surface. This information sets an upper bound on domain wall widths and offers a method for studying 3D domain structure at low temperatures.

  5. Depth resolved domain mapping in tetragonal SrTiO 3 by micro-Laue diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Merz, T. A.; Noad, H.; Xu, R.; Inoue, H.; Liu, W.; Hikita, Y.; Vailionis, A.; Moler, K. A.; Hwang, H. Y.

    2016-05-02

    We present depth resolved X-ray micro-Laue diffraction experiments on the low temperature domain structure of SrTiO3. At 80K, monochromatic X-ray diffraction shows an elongated out-of-plane unit cell axis within a matrix of in-plane oriented tetragonal unit cells. Full deviatoric strain mappings from white beam diffraction show a dominance of two tetragonal domain orientations (x- and z-axes) over a large area of sample surface. This information sets an upper bound on domain wall widths and offers a method for studying 3D domain structure at low temperatures.

  6. Evolution of microstructure and grain boundary character distribution of a tin bronze annealed at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Weijiu [College of Materials Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China); Chongqing Municipal Key Laboratory of Institutions of Higher Education for Mould Technology, Chongqing University of Technology, Chongqing 400054 (China); Chai, Linjiang, E-mail: chailinjiang@cqut.edu.cn [College of Materials Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China); Chongqing Municipal Key Laboratory of Institutions of Higher Education for Mould Technology, Chongqing University of Technology, Chongqing 400054 (China); Li, Zhijun; Yang, Xusheng [College of Materials Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China); Guo, Ning; Song, Bo [Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China)

    2016-04-15

    Specimens cut from a rolled tin bronze sheet were annealed at 400–800 °C for 1 h and evolution of their microstructures was then characterized in details by electron channeling contrast imaging and electron backscatter diffraction techniques. Particularly, statistics on special boundaries (SBs) with Σ ≤ 29 and network connectivity of random high angle boundaries (HABs) in the annealed specimens were examined to probe optimization potentials of grain boundary character distribution (GBCD) for this material. Results show that the deformed microstructure in the as-received material begins to be recrystallized when the annealing temperature increase to 500 °C and average grain sizes surge with further increasing temperatures. As a result of the recrystallization, a large number of annealing twins (with Σ3 misorientation) are produced, leading to remarkably increased fractions of SBs (f{sub SBs}). Thanks to preexisting dense low angle boundaries, the majority of SBs in the 500 °C specimen with only partial recrystallization are Σ3{sub ic} (incoherent) boundaries, which effectively disrupt connectivity of random HABs network. Although the f{sub SBs} can be further increased (up to 72.5%) in specimens with full recrystallization (at higher temperatures), the Σ3{sub ic} boundaries would be replaced to some extent by Σ3{sub c} (coherent) boundaries which do not contribute directly to optimizing the GBCD. This work should be able to provide clear suggestions on applying the concept of grain boundary engineering to tin bronze alloys. - Highlights: • The rolled tin bronze begins to be recrystallized as temperature increases to 500 °C. • A lot of SBs are produced after recrystallization and the highest f{sub SBs} is 72.5%. • Partially recrystallized specimen has the optimum GBCD due to more Σ3{sub ic} boundaries. • The Σ3{sub ic} boundaries are replaced by Σ3{sub c} boundaries after full recrystallization.

  7. Lead poisoning from use of bronze drinking vessels during the late Chinese Shang dynasty: an in vitro experiment.

    Science.gov (United States)

    Woolf, Alan D; Law, Terence; Yu, Hoi-Ying Elsie; Woolf, Nicholas; Kellogg, Mark

    2010-08-01

    Bronze drinking vessels famous for their intricate carvings and used by the aristocracy in the Chinese Shang dynasty (1555-1145 BCE) are known to have been fabricated with alloys containing soft metallic lead. The contribution of lead leaching from such vessels into the fermented grain wines drunk by the Chinese nobility in ancient times has not been previously estimated. Three bronze vessels containing 8% lead by weight were fabricated to resemble the late Shang bronze goblets. Shaoxing drinking rice wine was purchased locally and placed in the vessels, using a white grape wine and water as comparisons. Sampling was performed at baseline, 2 min, and then at days 1, 2, 4, and 7. Lead concentrations in the liquid matrix were measured using atomic absorption spectroscopy. Significant amounts of lead leached into the liquid within one day: 13,900 μg/L in water, 45,900 μg/L in rice wine, and 116,000 μg/L in white wine. Lead continued to leach into both the grape and rice wines with the passage of time. Significant lead contamination of Shaoxing rice wine was detected when it was left in bronze goblets fabricated to resemble the Shang dynasty vessels. If a liter of contaminated wine was drunk daily, the daily intake of lead could have been as high as 85 mg. Such a high degree of contamination could cause chronic lead poisoning, affecting the health of the Shang nobility who used bronze beverage containers, before lead was excluded from the manufacture of bronze.

  8. Hematology of the bronze Turkey (Meleagris gallopavo): Variations with age and gender

    OpenAIRE

    Schmidt,Elizabeth Moreira dos Santos; Paulillo, Antonio Carlos [UNESP; Martins, Gislaine Regina Vieira [UNESP; Lapera, Ivan Moura [UNESP; Testi, Alan Jonathan Pereira [UNESP; Nardi Junior, Leonildo [UNESP; Denadai, Janine [UNESP; Fagliari, José Jurandir [UNESP

    2009-01-01

    One hundred and ten Bronze Turkeys: 40 females (19-23 week-old), 13 males (19-23 week-old), 35 females (30-32 week-old) and 22 males (30-32 week-old), were investigated to analyse the influences of age and sex on hematological parameters. Statistical comparisons were made for differences in values between male and female and among different ages. Lymphocytes were the major circulating leukocyte for all birds. Total serum protein, lymphocytes and basophils were significantly different between ...

  9. Regeneration of plants from leaves of Chrysanthemum morifolium Ram. cv. Bronze Bornholm in in vitro cultures

    Directory of Open Access Journals (Sweden)

    Aurelia Ślusarkiewicz-Jarzina

    2014-01-01

    Full Text Available Plants were obtained from cultured in vitro leaves of Chrysanthemum morifolium Ram. cv. Bronze Bornholm. The leaves were inoculated on Murashige and Skoog medium (MS supplemented with cytokinins (kinetin - KIN, zeatin - ZEA, 6-benzyloaminopurine - BAP and auxins (2,4-dichlorophenoxyacetic acid - 2,4-D, α-naphtaleneacetic acid - NAA, 3-indolilacetic acid - IAA, p-fluorophenylalanine - PFA in various combinations and concentra-tions. The most suitable medium was that one which contained 4 mg/l KIN, 2 mg/l NAA and 50 mg/l PFA.

  10. Computed Tomography and Computed Radiography of late Bronze Age Cremation Urns from Denmark

    DEFF Research Database (Denmark)

    Harvig, Lise Lock; Lynnerup, Niels; Amsgaard Ebsen, Jannie

    2012-01-01

    To improve methods used to study prehistoric cremation rituals, cremation urns from the Danish late Bronze Age were examined using Computed Tomography and Computed Radiography (Digital X-ray). During microexcavation, the digital images were used as registration tool. Our results suggest...... that osteological ageing and sexing are more accurate when combining CT-images with excavated remains. Digital volume rendering further enables a compromised estimation of original cremation weight. Microexcavation is clearly a primary cause of bone fragmentation. Cremated remains affected by lower cremation...

  11. Electrolytic surface hardening of steel,castiron and aluminium-bronze

    Directory of Open Access Journals (Sweden)

    Suhas Keshav Paknik a r

    2006-08-01

    Full Text Available Electrolytic hardening process w as developed in USSR in the 1950s. The process w as developed but w as not com m ercially exploited. There is no evidence of w ork done on this process in India. The author has done this originalw ork applied to different m aterials like steel, castiron and alum inum -bronze.This paper gives details ofm icrostructuraltransform ations along w ith hardness value achieved. There is vitalscope for this process to becom e viable for surfacehardening and selective hardening ofsm allcom ponents.

  12. The Influence of Pseudomonas fluorescens on Corrosion Products of Archaeological Tin-Bronze Analogues

    Science.gov (United States)

    Ghiara, G.; Grande, C.; Ferrando, S.; Piccardo, P.

    2018-01-01

    In this study, tin-bronze analogues of archaeological objects were investigated in the presence of an aerobic Pseudomonas fluorescens strain in a solution, containing chlorides, sulfates, carbonates and nitrates according to a previous archaeological characterization. Classical fixation protocols were employed in order to verify the attachment capacity of such bacteria. In addition, classical metallurgical analytical techniques were used to detect the effect of bacteria on the formation of uncommon corrosion products in such an environment. Results indicate quite a good attachment capacity of the bacteria to the metallic surface and the formation of the uncommon corrosion products sulfates and sulfides is probably connected to the bacterial metabolism.

  13. An isotopic investigation into the origins and husbandry of Mid-Late Bronze Age cattle from Grimes Graves, Norfolk.

    OpenAIRE

    Towers, Jacqueline; Bond, Julie; Evans, Jane; Mainland, Ingrid; Montgomery, Janet

    2017-01-01

    Bioarchaeological evidence suggests that the site of Grimes Graves, Norfolk, characterised by the remains of several hundred Late Neolithic flint mineshafts, was a permanently settled community with a mixed farming economy during the Mid-Late Bronze Age (c. 1400 BCE – c. 800 BCE). The aim of this study was to investigate, through isotope ratio analysis (87Sr/86Sr, δ13C and δ18O), the origins and husbandry of Bronze Age cattle (Bos taurus) excavated from a mineshaft known as the “1972 shaft”. ...

  14. Micro-EDXRF surface analyses of a bronze spear head: Lead content in metal and corrosion layers

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, E. [Instituto Tecnologico e Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Departamento de Conservacao e Restauro, Faculdade de Ciencias e Tecnologia da Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Monte de Caparica (Portugal)], E-mail: elin@itn.pt; Valerio, P.; Araujo, M.F. [Instituto Tecnologico e Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Senna-Martinez, J.C. [Instituto de Arqueologia, Faculdade de Letras da Universidade de Lisboa, Cidade Universitaria, Campo Grande, 1600-214 Lisbon (Portugal)

    2007-09-21

    A bronze spear head from Central Portugal dated to Late Bronze Age has been analyzed by non-destructive micro-EDXRF in the metal surface and corrosion layers. The artifact had previously been analyzed using a conventional EDXRF spectrometer having a larger incident beam. The quantification of the micro-EDXRF analyses showed that lead content in corrosion layers can reach values up to four times higher than the content determined in the metal surface. Results obtained with the higher energy incident beam from the EDXRF equipment, although referring mainly to the corrosion layers, seem to suffer some influence from the surface composition of the metallic alloy.

  15. Growth of (101) faces of tetragonal lysozyme crystals: measured growth-rate trends

    Science.gov (United States)

    Forsythe, E. L.; Nadarajah, A.; Pusey, M. L.

    1999-01-01

    Previous extensive measurements of the growth rates of the (110) face of tetragonal lysozyme crystals have shown unexpected dependencies on the supersaturation. In this study, similar growth-rate measurements were performed for the (101) faces of the crystals. The data show a similar dependence on the supersaturation, becoming appreciable only at high supersaturations, reaching a maximum value and then decreasing. The (101) growth rates are larger at low supersaturations than the (110) growth rates under the same conditions and are smaller at high supersaturations. These trends suggest that the growth mechanism of the (101) face is similar to that of the (110) face: both processes involve the addition of multimeric growth units formed in solution, but the average size of the units for the (101) face is likely to be smaller than for the (110) face.

  16. Growth of (101) Faces of Tetragonal Lysozyme Crystals: Measured Growth Rate Trends

    Science.gov (United States)

    Forsythe, Elizabeth L.; Nadarajah, Arunan; Pusey, Marc L.

    1998-01-01

    Earlier extensive measurements of the growth rates of the (110) face of tetragonal lysozyme crystals had shown unexpected dependencies on the supersaturation. In this study similar growth rate measurements were done for the (101) faces of the crystals. The data show a similar dependence on the supersaturation, becoming appreciable only at high supersaturations, reaching a maximum value and then decreasing. As reported in earlier studies, the (101) growth rates are larger at low supersaturations than the (110) growth rates at the same conditions, and smaller at high supersaturations. These trends suggest that the growth mechanism of the (101) is similar to that of the (110) face, involving the addition of lysozyme aggregates formed in solution, but with a growth unit smaller than that of the (110) face.

  17. Linear electro-optical properties of tetragonal BaTiO

    Indian Academy of Sciences (India)

    c Indian Academy of Sciences. Vol. 59, No. 3 ... of tetragonal BaTiO3 are computed using a formalism [3] based on Phillips–Van Vechtens' dielectric theory .... 8.51. 7.12. 5.80. C (eV). 11.72. 11.40. 10.85. 13.1. 11.1. 9.1 fi. 0.93. 0.93. 0.93. 0.70. 0.71. 0.71 fc. 0.07. 0.07. 0.07. 0.30. 0.29. 0.29 f. 0.026. 0.034. 0.048. 0.163. 0.131.

  18. Stable tetragonal phase and magnetic properties of Fe-doped HfO2 nanoparticles

    Directory of Open Access Journals (Sweden)

    T. S. N. Sales

    2017-05-01

    Full Text Available In this paper, the effect in structural and magnetic properties of iron doping with concentration of 20% in hafnium dioxide (HfO2 nanoparticles is investigated. HfO2 is a wide band gap oxide with great potential to be used as high-permittivity gate dielectrics, which can be improved by doping. Nanoparticle samples were prepared by sol-gel chemical method and had their structure, morphology, and magnetic properties, respectively, investigated by X-ray diffraction (XRD, transmission electron microscopy (TEM and scanning electron microscopy (SEM with electron back scattering diffraction (EBSD, and magnetization measurements. TEM and SEM results show size distribution of particles in the range from 30 nm to 40 nm with small dispersion. Magnetization measurements show the blocking temperature at around 90 K with a strong paramagnetic contribution. XRD results show a major tetragonal phase (94%.

  19. Néel-Type Skyrmion Lattice in the Tetragonal Polar Magnet VOSe_{2}O_{5}.

    Science.gov (United States)

    Kurumaji, Takashi; Nakajima, Taro; Ukleev, Victor; Feoktystov, Artem; Arima, Taka-Hisa; Kakurai, Kazuhisa; Tokura, Yoshinori

    2017-12-08

    The formation of the triangular Skyrmion lattice is found in a tetragonal polar magnet VOSe_{2}O_{5}. By magnetization and small-angle neutron scattering measurements on the single crystals, we identify a cycloidal spin state at zero field and a Néel-type Skyrmion-lattice phase under a magnetic field along the polar axis. Adjacent to this phase, another magnetic phase of an incommensurate spin texture is identified at lower temperatures, tentatively assigned to a square Skyrmion-lattice phase. These findings exemplify the versatile features of Néel-type Skyrmions in bulk materials, and provide a further opportunity to explore the physics of topological spin textures in polar magnets.

  20. Crystal structure of the tetragonal polymorph of bis(1-ethyl-3-methylimidazolium tetrabromidocadmate

    Directory of Open Access Journals (Sweden)

    Tamara Đorđević

    2016-07-01

    Full Text Available Both unique Cd atoms in the tetragonal polymorph of bis(1-ethyl-3-methylimidazolium tetrabromidocadmate, (C6H11N22[CdBr4], occupy special positions (site symmetry -4. The crystal structure consists of isolated tetrahedral [CdBr4]2− anions which are surrounded by 1-ethyl-3-methylimidazolium cations. The methyl and ethyl side chains of the cations show positional disorder in a 0.590 (11:0.410 (11 ratio. In the crystal, (C6H11N2+ cations display three weak C—H...Br hydrogen-bond interactions through the imidazolium ring H atoms with the Br− ligands of the surrounding complex anions. The alkyl groups of the side chains are not involved in hydrogen bonding.

  1. Discovery of natural MgSiO3 tetragonal garnet in a shocked chondritic meteorite.

    Science.gov (United States)

    Tomioka, Naotaka; Miyahara, Masaaki; Ito, Motoo

    2016-03-01

    MgSiO3 tetragonal garnet, which is the last of the missing phases of experimentally predicted high-pressure polymorphs of pyroxene, has been discovered in a shocked meteorite. The garnet is formed from low-Ca pyroxene in the host rock through a solid-state transformation at 17 to 20 GPa and 1900° to 2000°C. On the basis of the degree of cation ordering in its crystal structure, which can be deduced from electron diffraction intensities, the cooling rate of the shock-induced melt veins from ~2000°C was estimated to be higher than 10(3)°C/s. This cooling rate sets the upper bound for the shock-temperature increase in the bulk meteorite at ~900°C.

  2. Structure of tetragonal martensite in the In95.42Cd4.58 cast alloy

    Science.gov (United States)

    Khlebnikova, Yu. V.; Egorova, L. Yu.; Rodionov, D. P.; Kazantsev, V. A.

    2017-11-01

    The structure of martensite in the In95.42Cd4.58 alloy has been studied by metallography, X-ray diffraction, dilatometry, and transmission electron microscopy. It has been shown that a massive structure built of colonies of tetragonal lamellar plates divided by a twin boundary {101}FCT is formed in the alloy under cooling below the martensite FCC → FCT transition temperature. The alloy recrystallizes after a cycle of FCT → FCC → FCT transitions with a decrease in the grain size by several times compared with the initial structure such fashion that the size of massifs and individual martensite lamella in the massif correlates with the change in the size of the alloy grain. Using thermal cycling, it has been revealed that the alloy tends to stabilize the high-temperature phase.

  3. Comparative characterization of rhombohedral and tetragonal PZN-PT single crystals

    Directory of Open Access Journals (Sweden)

    D. Kobor

    2011-06-01

    Full Text Available Ferroelectric single crystals Pb(Zn1/3Nb2/3O3–PbTiO3 (PZN–PT are promising full materials for nonresonant or large bandwidth transducers due to the large values of their piezoelectric properties (dij, kij and their mechanical quality factor (Qij. However the properties of these materials depend greatly on the content of titanium which influences very significantly the symmetry of the crystal. In this paper we try to understand the influence of the percentage of Titanium in these crystals by studying the two compositions that are in very different phases at room temperature (rhombohedral and tetragonal symmetries. Crystals of pure PZN–4.5PT and PZN-12PT were grown by a Flux technique. The typical single crystals obtained are brown yellow. The room temperature dielectric permittivity along the direction is about 900 for the PZN-12PT, which is smaller than that of the PZN–4.5PT (5840. The Curie point Tc of the tetragonal crystal is about 220 °C (which is higher than that of the rhombohedral one (166 °C, while the ferroelectric phase transition temperature is 130 °C for the PZN-4.5PT single crystal. The remnant polarization and coercive field of oriented crystals measured at 1 kHz are around 40 μC/cm2 and 3.30 kV/cm, respectively for the PZN-4.5PT, 27μC/cm2 and 11.1 kV/cm for the PZN-12PT single crystal. The d33 versus uniaxial stress shows that this coefficient is more stable for the single crystal with low Ti than for that with high rate of Ti. The study of temperature stability on these crystals shows a possible presence of an unidentified phase in the low and negative range temperature for the PZN-4.5PT.

  4. Superconductivity in an anomalously tetragonal YB2C3O6.62 single crystal: A possible singularity in the structural phase diagram

    DEFF Research Database (Denmark)

    Frello, T.; Andersen, N.H.; Baziljevich, M.

    2003-01-01

    superconducting. This makes the sample highly anomalous in two respects: with a stoichiometry of YBa2Cu3O6.62 the sample should have an orthorhombic symmetry, and a tetragonal undoped sample should not be superconducting at all. Our results corroborate previous findings of Topnikov [JETP Lett. 46, 577 (1987......)] of a tetragonal superconducting YBCO crystal with x=0.62....

  5. Effects of specimen size and yttria concentration on mechanical properties of single crystalline yttria-stabilized tetragonal zirconia nanopillars

    Science.gov (United States)

    Zhang, Ning; Asle Zaeem, Mohsen

    2017-07-01

    The nanoscale plastic deformation of yttria-stabilized tetragonal zirconia (YSTZ) is highly dependent on the crystallographic orientations, i.e., dislocation is induced when the loading direction is 45° tilted to {111} and {101} slip planes, while tetragonal to monoclinic phase transformation dominates the plastic deformation when loading direction is perpendicular to the slip planes. This study investigates the effects of specimen size and yttria concentration on the mechanical response of single crystalline YSTZ nanopillars. Through uniaxial compression test, the smaller-is-stronger phenomenon is revealed in nanopillars deformed through a dislocation motion mechanism. Serrated stacking faults are observed in the smallest nanopillar, while neat primary slip plane forms in the largest nanopillar. In contrast, the larger-is-stronger relation is observed in nanopillars in which deformation is mediated by tetragonal to monoclinic phase transformation. It is noted that the ratio of transformed monoclinic phase to the remaining tetragonal phase is the highest in the smallest nanopillar. The strength of nanopillars is identified to decrease by increasing the amount of yttria due to the creation of more oxygen vacancies that act as weak points to facilitate dislocation motion and accelerate phase transformation.

  6. Correlation between tetragonal zinc-blende structure and magnetocrystalline anisotropy of MnGa epilayers on GaAs(111)

    Energy Technology Data Exchange (ETDEWEB)

    Arins, A.W.; Jurca, H.F. [Laboratório de Superfícies e Interfaces, Universidade Federal do Paraná, Caixa Postal 19044, 81531-990 Curitiba, Paraná (Brazil); Zarpellon, J. [Laboratório de Superfícies e Interfaces, Universidade Federal do Paraná, Caixa Postal 19044, 81531-990 Curitiba, Paraná (Brazil); Universidade Estadual do Centro-Oeste-Campus Irati, PR 153km 7, CEP 84500-000, Irati, Paraná (Brazil); Fabrim, Z.E.; Fichtner, P.F.P. [Departamento de Metalurgia e Laboratório de Implantação Iônica-Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 Porto Alegre, RS (Brazil); Varalda, J; Schreiner, W.H.; Mosca, D.H [Laboratório de Superfícies e Interfaces, Universidade Federal do Paraná, Caixa Postal 19044, 81531-990 Curitiba, Paraná (Brazil)

    2015-05-01

    MnGa films of few nanometer thickness with tetragonal zinc-blende (TZB) structure were grown by molecular beam epitaxy on GaAs(111) substrates. These ultrathin films have high magnetization at room temperature with magnetic moment as high as 3.2 μ{sub B} per formula unit. A strong magnetocrystalline anisotropy energy (MAE) comparable to that reported to δ-MnGa films with body-centered tetragonal (BCT) structure with similar c/a=1.1 is observed. Electronic structure calculations using density functional theory (DFT) reveal a robust ferrimagnetic ground state at room temperature and confirm that zinc-blende structure with tetragonal distortion has a metastable character. The strong MAE is associated with anisotropy of orbital magnetic moment which is described by the symmetry of the spin-polarized charge density along the crystallographic axes. - Highlights: • MnGa epilayers with tetragonal zinc-blende structure were grown. • Density functional theory calculations reveal a robust ferrimagnetic ground state at room temperature. • Substantial magnetocrystalline anisotropy is associated with the symmetry of the spin-polarized charge density of Mn 4d sites. • MnGa alloy films are promising for spintronics applications.

  7. Tetragonal phase of cylinders self-assembled from binary blends of AB diblock and (A'B)nstar copolymers.

    Science.gov (United States)

    Jiang, Wenbo; Qiang, Yicheng; Liu, Meijiao; Li, Weihua; Qiu, Feng; Shi, An-Chang

    2017-09-27

    The phase behavior of binary blends composed of AB diblock and (A'B) n star copolymers is studied using the polymeric self-consistent field theory, focusing on the formation and stability of the stable tetragonal phase of cylinders. In general, cylindrical domains self-assembled from AB-type block copolymers are packed into a hexagonal array, although a tetragonal array of cylinders could be more favourable for lithography applications in microelectronics. The polymer blends are designed such that there is an attractive interaction between the A and A' blocks, which increases the compatibility between the two copolymers and thus suppresses the macroscopic phase separation of the blends. With an appropriate choice of system parameters, a considerable stability window for the targeted tetragonal phase is identified in the blends. Importantly, the transition mechanism between the hexagonal and tetragonal phases is elucidated by examining the distribution of the two types of copolymers in the unit cell of the structure. The results reveal that the short (A'B) n star copolymers are preferentially located in the bonding area connecting two neighboring domains in order to reduce extra stretching, whereas the long AB diblock copolymers are extended to further space of the unit cell.

  8. Shellfish from the Bronze Age Site of Clos des Châtaigniers (Mathieu, Normandy, France

    Directory of Open Access Journals (Sweden)

    Caroline Mougne

    2014-09-01

    Full Text Available This article provides initial results on the use of shellfish by the inhabitants of Clos des Châtaigniers, Normandy (France during the Late Bronze Age. The settlement is located at Mathieu, 10km from the coast. The French National Institute of Preventive Archaeological Research (INRAP conducted excavations on this site in 2010, under the direction of David Giazzon. A semi-circular domestic enclosure from the end of the Late Bronze Age was discovered. The diet of the inhabitants of Mathieu was partly based on mussels, which were found in large quantities. These shells were collected at low tide on a rocky to muddy/rocky shore. They were then transported inland to be eaten fresh or processed. Other marine invertebrates were also present on this site. Some of them were collected with the mussels. In fact, they were mixed with or fixed to this bivalve. Many other small fragments of shells are present on the site and could have come from the stomach contents of fish.

  9. Synthesis and ferroelectric properties of rare earth compounds with tungsten bronze-type structure

    Energy Technology Data Exchange (ETDEWEB)

    Bouziane, M., E-mail: bouzianemeryem@yahoo.fr [Laboratoire de Chimie du Solide Appliquee, Faculte des Sciences, Avenue Ibn Batouta, BP 1014, Rabat (Morocco); Taibi, M. [Laboratoire de Physico-Chimie des Materiaux, LAF 502, Ecole Normale Superieure, BP 5118, Rabat (Morocco); Boukhari, A. [Laboratoire de Chimie du Solide Appliquee, Faculte des Sciences, Avenue Ibn Batouta, BP 1014, Rabat (Morocco)

    2011-10-03

    Highlights: {center_dot} Polycrystalline materials with the tungsten bronze-type structure have been synthesized and characterized. {center_dot} Effect of the incorporation of rare earth ions and paramagnetic cations (Fe{sup 3+}) into a matrix ferroelectrically active was studied. {center_dot} Ferroelectric transition is pronounced by a large thermal hysteresis during the heating and cooling cycles. {center_dot} Phase transitions around T{sub c} were confirmed by differential scanning calorimetry (DSC) measurements. - Abstract: Polycrystalline materials with a general formula Pb{sub 2}Na{sub 0.8}R{sub 0.2}Nb{sub 4.8}Fe{sub 0.2}O{sub 15} (R = Dy, Eu, Sm, Nd, La) have been synthesized, in air by a high temperature solid state reaction method. X-ray diffraction study, at room temperature, revealed that they crystallize in the tungsten bronze-type structure. Dielectric properties were performed, in the temperature range 25-500 deg. C, at three different frequencies 10, 100 and 1000 kHz. The ferroelectric transition is pronounced by a large thermal hysteresis during the heating and cooling cycles. The determined Curie temperature values T{sub c} were discussed as a function of rare earth size. Phase transitions around T{sub c} for the investigated compounds were confirmed by differential scanning calorimetry (DSC) measurements.

  10. The Pranemuru project and the radiocarbon chronology of the Sardinian Bronze Age

    Directory of Open Access Journals (Sweden)

    Rubinos, Antonio

    2003-12-01

    Full Text Available New C-14 data collected by a Spanish team working in the Sardinian Pranemuru area, allow usthe possibility of revising the C-14 Chronology for the Nuragic Bronze Age and discussing the reliability of some of the dates, as well as the way they have been published, and their matching with the new official chronology for the Sardinian Bronze and Iron Ages, built on Dendro and C14 sequences for the Italian Peninsula.

    La obtención por parte del Proyecto Pranemuru de cerca de una veintena de dataciones radiocarbónicas para una microregión en época nurágica, de las que aquí se recogen discuten catorce, abre la posibilidad de revisar la cronología de la Edad del Bronce en Cerdeña, a la luz de las dataciones recogidas desde los años 90 por Trump (1990 y Tykot (1994 y, más recientemente, por Webster (2001, discutir la validez de las fechas en función de los criterios de recogida de muestra, contexto arqueológico, desviación estándar y forma en que ha sido publicada, así como contrastarla con la cronología propuesta recientemente para la Protohistoria sarda, de acuerdo con la Dendrocronología y Cronología Radiocarbónica para la Italia peninsular (Lo Schiavo 2002.

  11. $Nb_{3}Sn macrostructure, microstructure, and property comparisons for bronze and internal Sn process strands

    CERN Document Server

    Lee, P J; Larbalestier, D C

    2000-01-01

    The variation in irreversibility field, B*(T), with temperature has been measured for Nb/sub 3/Sn superconducting strands manufactured for ITER using vibrating sample and SQUID magnetometers. The high performance strands were developed for both high transport critical current density, J/sub c/, and low hysteresis loss. Despite a wide variety of designs and components, the strands could be split into two distinctive groups, based on the extrapolated irreversibility fields, which lie about 10% lower than the upper critical field. "Bronze-process" strands exhibited consistently higher B*(T) (28 T to 31 T) compared with "internal Sn" process (24 T to 26 T) conductors. The intrinsic critical current density of the superconductor, J/sub c (sc)/, and the specific pinning force of the grain boundaries, Q/sub gb/, were evaluated using the measured J/sub c/, and image analysis of the macro- and micro-structures. A bronze-processed Nb(-Ta)/sub 3 /Sn was found to have a higher J/sub c(sc)/ but lower Q/sub gb/ than Nb/sub...

  12. Las Lunas (Yuncler, Toledo. A Bronze Age hoard with metallic materials from the southern Iberian Meseta

    Directory of Open Access Journals (Sweden)

    Urbina Martínez, Dionisio

    2010-06-01

    Full Text Available Here we present the results of the preliminary study carried out on a new group of metallic materials of the Final Bronze Age, recovered at the end of 2008 in the archaeological excavations at the settlement of Las Lunas (Yuncler, Toledo, Spain. Its geographical situation far away from the main zones of distribution of this type of finds, the singularity of the materials, and the evidence of Atlantic and Mediterranean relations make these materials a remarkable sample for the study of the Final Bronze Age in the centre of the Iberian Peninsula.

    Se exponen los resultados del primer estudio realizado sobre un nuevo conjunto de materiales metálicos del Bronce Final recuperado a finales de 2008 en las excavaciones arqueológicas del yacimiento de Las Lunas (Yuncler, Toledo, España. La localización geográfica del hallazgo, lejos de las principales zonas de dispersión conocidas para este tipo de conjuntos, la singularidad de los objetos que integra, y las relaciones atlánticas y mediterráneas que evidencian sus materiales, lo convierten en un ejemplo destacado para el estudio de este período en el centro de la Península Ibérica.

  13. Vegetation development in the Middle Euphrates and Upper Jazirah (Syria/Turkey) during the Bronze Age

    Science.gov (United States)

    Deckers, Katleen; Pessin, Hugues

    2010-09-01

    Vegetation changes are reconstructed based on more than 51,000 charcoal fragments of more than 380 samples from nine Bronze Age sites in northern Syria and southern Turkey. In addition to fragment proportions, special attention was paid to the frequency of Pistacia relative to Quercus and Populus/ Salix relative to Tamarix, fruit-tree ubiquity, and riverine diversity in order to gain an improved understanding of the human versus climatic impact on the vegetation. The results indicate that human impacts first took place within the riverine forest. This phase was followed by land clearing within the woodland steppe, especially in the northern portion of the study area. In the south near Emar, the woodland steppe probably disappeared by the Late Bronze Age. It is uncertain whether this was caused by aridification and/or human clearing. The northward shift of the Pistacia-woodland steppe is very likely a result of climatic drying that occurred throughout the entire period under investigation. Although increased deforestation is evident through time, the small proportions of imported wood indicate that local resources were still available.

  14. Animal exploitation in northeast Tibetan Plateau during Neolithic-Bronze Age

    Science.gov (United States)

    Dong, Guanghui; Ren, Lele; Li, Zhipeng; Zhang, Dongju; Chen, Fahu

    2017-04-01

    The history and driving force for prehistoric human occupation of the Tibetan Plateau has been intensively concerned in recent years. Multidisciplinary studies reveal that human extensively and year-roundly settled below 2500 m asl in northeast Tibetan Plateau (NETP) since 5200BP mainly with the utilization of millet crops, and above 3000 m asl post 3600BP primarily with cold-tolerant barley. However, the strategy for human animal utilization during Neolithic and Bronze periods in NETP still remains enigmatic. We collected and identified hundreds of animal bones from 14 Neolithic and Bronze sites in NETP, with the application of radiocarbon dating, carbon and nitrogen isotopes analysis, and ancient DNA analysis, we explore the changing patterns of animal utilization, and potential human behaviours for taming wild animals in this area throughout late prehistoric times. These works shed lights for understanding when and how husbandry and pastoral economies emerged, and how prehistoric human adapted to the high-cold environment of the Tibetan Plateau..

  15. Study on effect of cubic- and tetragonal phased BaTiO{sub 3} on the electrical and thermal properties of polymeric nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Thanki, A.A.; Goyal, R.K., E-mail: rkgoyal72@yahoo.co.in

    2016-11-01

    Polymer matrix nanocomposites based on polycarbonate (PC) and nanosized-cubic/tetragonal phases of barium titanate (BaTiO{sub 3}) were fabricated using a solution method followed by hot pressing. The content of both cubic- and tetragonal phased BaTiO{sub 3} was varied from 0 to 50 wt%. For a given weight fraction, the dielectric constant of the nanocomposites containing tetragonal BaTiO{sub 3} is more than those of cubic BaTiO{sub 3} filled nanocomposites. Moreover, cubic BaTiO{sub 3}/PC nanocomposites showed significantly lower dissipation factor than those of tetragonal BaTiO{sub 3}/PC nanocomposites. The dielectric constant of the nanocomposites was found to be frequency-independent. The microhardness of the nanocomposites increased with increase in the BaTiO{sub 3} content (both cubic- and tetragonal-phased) compared to the pure matrix. Scanning electron microscopy showed better dispersion and good interaction of the tetragonal BaTiO{sub 3} nanoparticles in the matrix. The addition of cubic BaTiO{sub 3} nanoparticles significantly reduced the thermal stability of the nanocomposites compared to matrix while the addition of tetragonal BaTiO{sub 3} nanoparticles decreased it slightly. The glass transition temperature of the cubic BaTiO{sub 3}/PC nanocomposites decreased significantly, whereas it reduced slightly for the tetragonal BaTiO{sub 3}/PC nanocomposites. - Highlights: • The effect of cubic-BaTiO{sub 3} and tetragonal-BaTiO{sub 3} nanoparticles were studied. • Cubic-BaTiO{sub 3} nanoparticles showed better microhardness. • Tetragonal-BaTiO{sub 3} nanoparticles showed better dielectric and thermal properties. • Frequency independent dielectric constants of the nanocomposites were observed.

  16. Metal Adornments of Clothing and Headwear in the Bronze Age of Western Siberia (issues of research and reconstruction ..

    Directory of Open Access Journals (Sweden)

    Umerenkova Olga V.

    2017-09-01

    Full Text Available The article considers issues related to the principals of scientific approach, methods and procedure of costume reconstruction on the basis of archaeological materials dating back to the Bronze Age discovered in the territory of Western Siberia. The costume is considered by researchers as one of the brightest manifestations of material culture. Its decoration provides multidisciplinary information containing elements of ideology and aesthetic norms together with traditions and social relationships. Reconstruction of clothing and headwear adornments in archaeological literature related to the Bronze Age is one of the understudied topics. Researchers use various sources for its recreation: archaeological materials, written historical, literature and folklore sources, and fine art items. A significant amount of source items has accumulated over the last decades, although the analysis and principles of processing thereof have not been sufficiently covered in special literature. In order to increase the informative capabilities of adornments as sources for the reconstruction of the Bronze Age costume, the author suggested a scheme of accounting for the location of adornments with respect to the remains of the buried when the excavations are documented. The article features the results of the author's reconstruction of women's headwear decoration with metal articles executed on the basis of Bronze Age materials.

  17. Analyzing Lead Content in Ancient Bronze Coins by Flame Atomic Absorption Spectroscopy: An Archaeometry Laboratory with Nonscience Majors

    Science.gov (United States)

    Donais, Mary Kate; Whissel, Greg; Dumas, Ashley; Golden, Kathleen

    2009-01-01

    A unique, interdisciplinary collaboration between chemistry and classics has led to the development of an experiment for nonscience majors. This instrumental analysis experiment was designed for use in an archaeology course to quantify the amount of lead in ancient bronze coins. The coins were corroded beyond visual identification, so provenance…

  18. Structure and properties of quarternary and tetragonal Heusler compounds for spintronics and spin transver torque applications

    Energy Technology Data Exchange (ETDEWEB)

    Zamani, Vajiheh Alijani

    2012-03-07

    shown that the series Mn{sub 3-x}Co{sub x}Ga crystallizes in the inverse tetragonal structure, for x=0.1-0.4 and in the cubic inverse Heusler structure, for x=0.6-1. In this series, while the tetragonal alloys, hard magnets, exhibit the features typically attractive for STT applications, the cubic systems, soft magnets, present 100% spin polarized materials obeying the Slater-Pauling rule. In Mn{sub 2-x}Rh{sub 1+x}Sn series, Mn{sub 2}RhSn crystallizes in the inverse tetragonal structure, shows a hard-magnetic hysteresis loop and does not follow the Slater-Pauling rule. With substituting Mn by Rh, the inverse cubic structure is observed. All cubic samples show perfect Slater-Pauling behavior and a soft hysteresis loop.

  19. Growth and structural characterization of orthorhombic and tetragonal SrCuO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Mihailescu, C.N., E-mail: christian@ucy.ac.cy [Nanotechnology Research Center and Department of Mechanical and Manufacturing Engineering, University of Cyprus, 75 Kallipoleos Av., PO Box 20537, 1678 Nicosia (Cyprus); National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor St., PO Box MG-36, 077125 Magurele (Romania); Pasuk, I. [National Institute of Materials Physics, 105 Bis Atomistilor St., PO Box MG-7, 077125 Magurele (Romania); Athanasopoulos, G.I. [Nanotechnology Research Center and Department of Mechanical and Manufacturing Engineering, University of Cyprus, 75 Kallipoleos Av., PO Box 20537, 1678 Nicosia (Cyprus); Luculescu, C. [National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor St., PO Box MG-36, 077125 Magurele (Romania); Socol, M. [National Institute of Materials Physics, 105 Bis Atomistilor St., PO Box MG-7, 077125 Magurele (Romania); Saint-Martin, R.; Revcolevschi, A. [LPCES – ICMMO – Bât 410, Université Paris-Sud XI, 15 Georges Clémenceau St., 91405 Orsay Cedex (France); Giapintzakis, J., E-mail: giapintz@ucy.ac.cy [Nanotechnology Research Center and Department of Mechanical and Manufacturing Engineering, University of Cyprus, 75 Kallipoleos Av., PO Box 20537, 1678 Nicosia (Cyprus)

    2013-08-01

    Epitaxial SrCuO{sub 2} thin films were grown on (0 0 1) SrTiO{sub 3} substrates by pulsed laser deposition using a stoichiometric target. X-ray diffraction indicated that the SrCuO{sub 2} films undergo a structural phase transition as a function of the substrate temperature. Films deposited at temperatures below 600 °C exhibit a tetragonal phase with the c-axis oriented along the growth direction while films deposited at temperatures above 700 °C exhibit an orthorhombic phase with the b-axis oriented along the growth direction. Atomic force microscopy indicated that the as-grown film surfaces are rather smooth and the roughness increases with increasing substrate temperature. Energy dispersive X-ray spectroscopy in agreement with X-ray diffraction intensity ratio data revealed that all films are non-stoichiometric and contain Sr vacancies (Sr/Cu ∼ 0.8). The influence of film-substrate lattice matching and substrate temperature on the structural phase transition is discussed.

  20. Growth and structural characterization of orthorhombic and tetragonal SrCuO2 thin films

    Science.gov (United States)

    Mihailescu, C. N.; Pasuk, I.; Athanasopoulos, G. I.; Luculescu, C.; Socol, M.; Saint-Martin, R.; Revcolevschi, A.; Giapintzakis, J.

    2013-08-01

    Epitaxial SrCuO2 thin films were grown on (0 0 1) SrTiO3 substrates by pulsed laser deposition using a stoichiometric target. X-ray diffraction indicated that the SrCuO2 films undergo a structural phase transition as a function of the substrate temperature. Films deposited at temperatures below 600 °C exhibit a tetragonal phase with the c-axis oriented along the growth direction while films deposited at temperatures above 700 °C exhibit an orthorhombic phase with the b-axis oriented along the growth direction. Atomic force microscopy indicated that the as-grown film surfaces are rather smooth and the roughness increases with increasing substrate temperature. Energy dispersive X-ray spectroscopy in agreement with X-ray diffraction intensity ratio data revealed that all films are non-stoichiometric and contain Sr vacancies (Sr/Cu ˜ 0.8). The influence of film-substrate lattice matching and substrate temperature on the structural phase transition is discussed.

  1. First-principles study of nanotubes within the tetragonal, hexagonal and dodecagonal cycle structures

    Science.gov (United States)

    BabaeiPour, M.; Safari, E. Keshavarz; Shokri, A. A.

    2017-02-01

    A systematic study has been done on the structural and electronic properties of carbon, boron nitride and aluminum nitride nanotubes with structure consisting of periodically distributed tetragonal (T ≡A2X2), hexagonal (H ≡A3X3) and dodecagonal (D ≡A6X6) (AX=C2, BN, AlN) cycles. The method has been performed using first-principles calculations based on density functional theory (DFT). The optimized lattice parameters, density of state (DOS) curves and band structure of THD-NTs are obtained for (3, 0) and (0, 2) types. Our calculation results indicate that carbon nanotubes of these types (THD-CNTs) behave as a metallic, but the boron nitride nanotubes (THD-BNNTs) (with a band gap of around 4 eV) as well as aluminum nitride nanotubes (THD-AlNNTs) (with a band gap of around 2.6 eV) behave as an semiconductor. The inequality in number of atoms in different directions is affected on structures and diameters of nanotubes and their walls curvature.

  2. Wear behavior of tetragonal zirconia polycrystal versus titanium and titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kanbara, Tsunemichi; Yajima, Yasutomo [Department of Oral Implantology, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba 261-8502 (Japan); Yoshinari, Masao, E-mail: yosinari@tdc.ac.jp [Division of Oral Implant Research, Oral Health Science Center, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba 261-8502 (Japan)

    2011-04-15

    The aim of this study was to clarify the influence of tetragonal zirconia polycrystal (TZP) on the two-body wear behavior of titanium (Ti). Two-body wear tests were performed using TZP, two grades of cp-Ti or Ti alloy in distilled water, and the cross-sectional area of worn surfaces was measured to evaluate the wear behavior. In addition, the surface hardness and coefficient of friction were determined and an electron probe microanalysis performed to investigate the underlying mechanism of wear. The hardness of TZP was much greater than that of Ti. The coefficient of friction between Ti and Ti showed a higher value than the Ti/TZP combination. Ti was more susceptible to wear by both TZP and Ti than TZP, indicating that the mechanism of wear between TZP and Ti was abrasive wear, whereas that between Ti and Ti was adhesive wear. No remarkable difference in the amount of wear in Ti was observed between TZP and Ti as the opposite material, despite the hardness value of Ti being much smaller than that of TZP. (communication)

  3. Controllable Photovoltaic Effect of Microarray Derived from Epitaxial Tetragonal BiFeO3Films.

    Science.gov (United States)

    Lu, Zengxing; Li, Peilian; Wan, Jian-Guo; Huang, Zhifeng; Tian, Guo; Pan, Danfeng; Fan, Zhen; Gao, Xingsen; Liu, Jun-Ming

    2017-08-16

    Recently, the ferroelectric photovoltaic (FePV) effect has attracted great interest due to its potential in developing optoelectronic devices such as solar cell and electric-optical sensors. It is important for actual applications to realize a controllable photovoltaic process in ferroelectric-based materials. In this work, we prepared well-ordered microarrays based on epitaxially tetragonal BiFeO 3 (T-BFO) films by the pulsed laser deposition technique. The polarization-dependent photocurrent image was directly observed by a conductive atomic force microscope under ultraviolet illumination. By choosing a suitable buffer electrode layer and controlling the ferroelectric polarization in the T-BFO layer, we realized the manipulation of the photovoltaic process. Moreover, based on the analysis of the band structure, we revealed the mechanism of manipulating the photovoltaic process and attributed it to the competition between two key factors, i.e., the internal electric field caused by energy band alignments at interfaces and the depolarization field induced by the ferroelectric polarization in T-BFO. This work is very meaningful for deeply understanding the photovoltaic process of BiFeO 3 -based devices at the microscale and provides us a feasible avenue for developing data storage or logic switching microdevices based on the FePV effect.

  4. Search for magnetism in transition metal atoms doped tetragonal graphene: A DFT approach

    Science.gov (United States)

    Chowdhury, Suman; Majumdar, Arnab; Jana, Debnarayan

    2017-11-01

    The discovery of different two-dimensional (2D) materials both theoretically and experimentally, can change the scenario of the current electronic industry because of their intriguing properties. Among the 2D materials, the first one which was discovered experimentally was graphene. In this work we have studied the electronic and magnetic properties of a new allotrope of disordered graphene, which is not hexagonal, rather possesses tetragonal symmetry known as T-graphene (TG). Density functional theory (DFT) has been thoroughly employed to study the relevant electronic properties. In previous works, it has been reported that pristine TG is non-magnetic. It is also known that, introducing transition metal (TM) atoms is a feasible way to control the electronic and magnetic properties. Here we have reported the relevant properties of four TM atoms i.e. Sc, V, Cr and Mn doped TG. From the defect formation energy study, it has been noticed that all the structures are endothermic in nature. For each case, we have found appreciable amount of magnetic moment. With increasing atomic weight of the dopant atom, the magnitude of the magnetic moment also increases. We have tried to explain this magnetic ordering with the help of spin-polarized partial density of states (PDOS). Controlling spin degrees of freedom is important for building spintronic devices. From that point of view, we hope this study will be useful to build TG based spintronic devices.

  5. Tetragonal-Like Phase in Core–Shell Iron Iron-Oxide Nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Maninder; McCloy, John S.; Kukkadapu, Ravi; Pearce, Carolyn; Tucek, Jiri; Bowden, Mark; Engelhard, Mark; Arenholz, Elke; Qiang, You

    2017-05-11

    Two sizes of iron/iron-oxide (Fe/Fe-oxide) nanoclusters (NCs) of 10 nm and 35 nm diameters were prepared using a cluster deposition technique. Both these NCs displayed XRD peaks due to body-centered cubic (bcc) Fe0 and magnetite-like phase. Mossbauer spectroscopy (MS) measurements: a) confirmed the core-shell nature of the NCs, b) the Fe-oxide shell to be nanocrystalline and partially oxidized, and c) the Fe-oxide spins are significantly canted. In addition to the bcc Fe and magnetite-like phases, a phase similar to tetragonal σ-Fe-Cr (8% Cr) was CLEARLY evident in the larger NC, based on X-ray diffraction. Origin of the tetragonallike phase in the larger NC was not clear but could be due to significant distortion of the Fe0 core lattice planes; subtle peaks due to this phase were also apparent in the smaller NC. Unambiguous evidence for the presence of such a phase, however, was not clear from MS, X-ray photoelectron spectroscopy, vibrating sample magnetometry, X-ray magnetic circular dichroism, nor transmission electron microscopy. To our knowledge, this is the first report of tetragonallike phase in the Fe/Fe-oxide core-shell systems.

  6. Possible Itinerant-Electron Canted Antiferromagnetism in Tetragonal Antiperovskite Cr3AsN

    Science.gov (United States)

    Waki, Takeshi; Takao, Kenta; Tabata, Yoshikazu; Ohta, Hiroto; Yajima, Takeshi; Hiroi, Zenji; Nakamura, Hiroyuki

    2017-10-01

    We studied the magnetic, transport, and structural properties of the tetragonally distorted antiperovskite nitride Cr3AsN. A ferromagnetic-like increase in magnetic susceptibility below the magnetic transition temperature Tm = 255 K is reported for the first time. This magnetic transition is of the second order and not associated with a structural transition, unlike that in Mn-based antiperovskites. Although the observed spontaneous moment of 0.062 μB/Cr at the lowest temperature is very small, the reduction in the magnetic scattering in resistivity and spontaneous magnetostriction below Tm indicate the existence of a magnetic moment larger than the observed spontaneous magnetization. Zero-field 53Cr and 75As NMR results below Tm reveal the presence of a static moment of ˜0.5 μB at the Cr sites and a hyperfine field lying in the c-plane at the As site. Macroscopic and microscopic observations suggest the incomplete compensation of antiferromagnetically coupled moments. Canted antiferromagnetism is proposed for the itinerant-electron magnet.

  7. Physical properties of the tetragonal CuMnAs: A first-principles study

    Science.gov (United States)

    Máca, F.; Kudrnovský, J.; Drchal, V.; Carva, K.; Baláž, P.; Turek, I.

    2017-09-01

    Electronic, magnetic, and transport properties of the antiferromagnetic (AFM) CuMnAs alloy with tetragonal structure, promising for the AFM spintronics, are studied from first principles using the Vienna ab initio simulation package. We investigate the site occupation of sublattices and the lattice parameters of three competing phases. We analyze the factors that determine which of the three conceivable structures will prevail. We then estimate formation energies of possible defects for the experimentally prepared lattice structure. MnCu and CuMn antisites as well as Mn ↔Cu swaps and vacancies on Mn or Cu sublattices were identified as possible candidates for defects in CuMnAs. We find that the interactions of the growing thin film with the substrate and with vacuum as well as the electron correlations are important for the phase stability while the effect of defects is weak. In the next step, using the tight-binding linear muffin-tin orbital method for the experimental structure, we estimate transport properties for systems containing defects with low formation energies. Finally, we determine the exchange interactions and estimate the Néel temperature of the AFM-CuMnAs alloy using the Monte Carlo approach. A good agreement of the calculated resistivity and Néel temperature with experimental data makes it possible to draw conclusions concerning the competing phases.

  8. Growth morphology of tetragonal ABCO 4 compounds: theory and observations on Czochralski grown crystals

    Science.gov (United States)

    Woensdregt, C. F.; Janssen, H. W. M.; Gloubokov, A.; Pajaczkowska, A.

    1997-02-01

    Tetragonal ABCO 4 compounds, where A  Sr, Ca, B  rare earth elements and C  Ga or Al, are potential substrate candidates for high-frequency superconducting films. The Hartman-Perdok theory (HPT) explains the relation between crystal structure and morphology and provides the atomic surface topology of the crystalline interface. Theoretical growth forms can be constructed from computed attachment energies, Ehkla, which is assumed to be directly proportional to the growth rate for F faces. HPT has been applied to CaYAlO 4 as a model for all ABCO 4 compounds with a K 2NiF 4 crystal structure. F forms are {002}, {101}, {103}, {110}, {112}. {200}, {211} and {213}. The theoretical growth form is planar following {001} with {101} and {110} as lateral forms. At lower effective charges on oxygen, qO, the growth forms are still tabular, but the order of importance of lateral forms changes as function of qO. When the ions on the slice boundaries are ordered, {110} will be absent for the model with the formal charges and replaced by {112} in the case of models with less negative oxygen charges. As-grown crystals show often inhomogeneities in color parallel to the {110} interface. This can be explained by the surface topology of {110}.

  9. Polar instability under electrostatic doping in tetragonal SnTi O3

    Science.gov (United States)

    Ma, Chao; He, Xu; Jin, Kui-juan

    2017-07-01

    How to make the metallicity compatible with a polar structure for forming a "polar metal" has been an interesting and important topic since the polar structure was discovered in metallic LiOs O3 . Here, we present robust polar instability under electrostatic doping in tetragonal SnTi O3 based on our first-principles calculations. The mechanism for polar distortion surviving free carriers is investigated from the "weak-coupling" perspective. The contributions of different interactions between two polar modes in a "ferroelectric" phase transition are also studied. We found that the short-range interaction contributes the most for lowering the total energy during the ferroelectricphase transition. Moreover, the dipole-dipole interaction between two polar modes of oxygen atoms provides the largest energy gain among local interactions, which cannot be screened out by doping. We propose that the promising candidates for noncentrosymmetric metals obtained by doping are ferroelectrics with bonding states responsible for polar distortions away from the Fermi level. We believe that this mechanism sheds light on a method to obtain noncentrosymmetric metals from a large amount of ferroelectric perovskite oxides by doping.

  10. Dielectric investigations in nanostructured tetragonal BaTiO{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, L.G.D.; Alves, M.F.S.; Cótica, L.F. [Departamento de Física, Universidade Estadual de Maringá. Av. Colombo, 5790, Maringá 87020-900, PR (Brazil); Gotardo, R.A.M.; Nascimento, W.J.; Garcia, D.; Eiras, J.A. [Departamento de Física, Universidade Federal de São Carlos. Rod. Washington Luiz, km 235, São Carlos 13565-905, SP (Brazil); Santos, I.A., E-mail: iasantos@dfi.uem.br [Departamento de Física, Universidade Estadual de Maringá. Av. Colombo, 5790, Maringá 87020-900, PR (Brazil)

    2013-05-15

    Highlights: ► Nanostructured BaTiO{sub 3} ceramics processed by an innovative protocol. ► Dielectric relaxations related to strains and vacancies. ► Dielectric and ferroelectric properties enhanced by strain. - Abstract: In this paper, structural and dielectric properties of BaTiO{sub 3} ceramics obtained under extreme conditions were investigated. The temperature dependent dielectric investigations revealed that the phase transition temperatures of the BaTiO{sub 3} ceramics were raised as a function of residual strains associated to the nanostructuration, while structural characterizations showed a tetragonal arrangement at room temperature. From the frequency dependence analyses of the imaginary parts of dielectric permittivity, impedance and modulus function, three relaxation processes were identified. Two of them exhibit activation energies of 0.45 and 0.63 eV, and were attributed to single and double-ionization of oxygen vacancies. The whole set of results also indicated that the electrons resulting from the ionization of oxygen vacancies are trapped and do not contribute to the electrical conductivity, while the physical properties of the analyzed samples were enhanced by retaining a strained microstructure.

  11. Initial Bacterial Adhesion on Different Yttria-Stabilized Tetragonal Zirconia Implant Surfaces in Vitro

    Directory of Open Access Journals (Sweden)

    Lamprini Karygianni

    2013-12-01

    Full Text Available Bacterial adhesion to implant biomaterials constitutes a virulence factor leading to biofilm formation, infection and treatment failure. The aim of this study was to examine the initial bacterial adhesion on different implant materials in vitro. Four implant biomaterials were incubated with Enterococcus faecalis, Staphylococcus aureus and Candida albicans for 2 h: 3 mol % yttria-stabilized tetragonal zirconia polycrystal surface (B1a, B1a with zirconium oxide (ZrO2 coating (B2a, B1a with zirconia-based composite coating (B1b and B1a with zirconia-based composite and ZrO2 coatings (B2b. Bovine enamel slabs (BES served as control. The adherent microorganisms were quantified and visualized using scanning electron microscopy (SEM; DAPI and live/dead staining. The lowest bacterial count of E. faecalis was detected on BES and the highest on B1a. The fewest vital C. albicans strains (42.22% were detected on B2a surfaces, while most E. faecalis and S. aureus strains (approximately 80% were vital overall. Compared to BES; coated and uncoated zirconia substrata exhibited no anti-adhesive properties. Further improvement of the material surface characteristics is essential.

  12. Calzirtite after tetragonal ZrO{sub 2} studied by transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jing-Shi; Shen, Pouyan [National Sun Yat-sen Univ., Kaohsiung (Taiwan, Province of China)

    1996-11-01

    Reactive sintering of CaO, ZrO{sub 2}, and TiO{sub 2}(2:5:2 in molar ratio) powders at 1320{degrees}C for 2 weeks caused the topotaxial formation of calzirite (Ca{sub 2}Zr{sub 5}Ti{sub 2}O{sub 16}, a 3 x 3 x 2 fluorite superstructure denoted as czt) after ZrO{sub 2} nuclei, presumably of tetragonal (t-) symmetry with an orientational relationship [100]{sub t}//[100]{sub czt}; [001]{sub t}//[001]{sub czt}. To maintain a t-ZrO{sub 2} precursor for the subsequent calzirtite formation, it was essential to have Ti{sup 4+} dissolved faster than Ca{sup 2+} in the ZrO{sub 2} lattice. The calzirtite grains thus formed have no twin variants but have ordered domains and a new supercell which can be indexed as an 6 x 3 x 4 array of the fluorite subcell, due to ordering of two closely spaced M(1) positions (0.93Ti + 0.07Zr, determined by Rossell). The 6 x 3 x 4 supercell appeared as disk-like variants in the calzirite matrix.

  13. Changes in X-ray photoelectron spectra of yttria-tetragonal zirconia polycrystal by ion sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Eiko; Yoshinari, Masao [Tokyo Dental College, Oral Health Science Center, Tokyo, Chiyoda-ku (Japan)

    2016-04-15

    This paper reports changes in X-ray photoelectron spectroscopy spectra of yttria-tetragonal zirconia polycrystal (Y-TZP) brought about by Ar ion sputtering. The changes in the core-level spectra of Y-TZP suggest that preferential sputtering of oxygen occurred. A new peak was observed near 0 eV binding energy accompanied with changes in the core-level spectra by the sputtering. After 18 h in a high vacuum following the sputtering, the spectra changed by the sputtering were returned to their original shapes. In contrast, the color of Y-TZP was changed from white to pale brown by X-ray irradiation and was changed from pale brown to dark gray by ion sputtering. However, when the new peak near 0 eV decreased after 18 h, no color change was observed. Therefore, it is thought that the new peak was mainly derived from electrons trapped in various kinds of oxygen vacancies created by the sputtering in other than color centers. (orig.)

  14. Lead-free, bronze-based surface layers for wear resistance in axial piston hydraulic pumps

    Energy Technology Data Exchange (ETDEWEB)

    Vetterick, Gregory Alan [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    Concerns regarding the safety of lead have provided sufficient motivation to develop substitute materials for the surface layer on a thrust bearing type component known as a valve plate in axial piston hydraulic pumps that consists of 10% tin, 10% lead, and remainder cooper (in wt. %). A recently developed replacement material, a Cu-10Sn-3Bi (wt.%) P/M bronze, was found to be unsuitable as valve plate surface layer, requiring the development of a new alloy. A comparison of the Cu-1-Sn-10Pb and Cu-10Sn-3Bi powder metal valve plates showed that the differences in wear behavior between the two alloys arose due to the soft phase bismuth in the alloy that is known to cause both solid and liquid metal embrittlement of copper alloys.

  15. Rapid climate change did not cause population collapse at the end of the European Bronze Age.

    Science.gov (United States)

    Armit, Ian; Swindles, Graeme T; Becker, Katharina; Plunkett, Gill; Blaauw, Maarten

    2014-12-02

    The impact of rapid climate change on contemporary human populations is of global concern. To contextualize our understanding of human responses to rapid climate change it is necessary to examine the archeological record during past climate transitions. One episode of abrupt climate change has been correlated with societal collapse at the end of the northwestern European Bronze Age. We apply new methods to interrogate archeological and paleoclimate data for this transition in Ireland at a higher level of precision than has previously been possible. We analyze archeological (14)C dates to demonstrate dramatic population collapse and present high-precision proxy climate data, analyzed through Bayesian methods, to provide evidence for a rapid climatic transition at ca. 750 calibrated years B.C. Our results demonstrate that this climatic downturn did not initiate population collapse and highlight the nondeterministic nature of human responses to past climate change.

  16. A mineralogical study of Late Bronze Age ceramics from Palatca (Transylvania, Romania

    Directory of Open Access Journals (Sweden)

    Lucretia Ghergari

    2012-01-01

    Full Text Available Our paper studies the mineralogical and petrographical characteristics of 28 ceramic fragments that were excavated in the village of Palatca, Transylvania (Romania. Optical microscopy, X-Ray powder diffraction (XRD, scanning electron microscopy (SEM, grain size analyses, and porosity measurements were used to investigate the samples. Our objective was to describe or reconstruct the corresponding products and to elucidate the manufacturing process, the firing techniques, and the transformation pathways. Based on our results, we conclude that the Late Bronze Age ceramics (1600-1300 BC were produced from clay and temper material such as river sand and ceramoclasts. It has been modeled by hand and fired between 800 and 950°C. For most samples, we can narrow the temperature range to 850-900°C. We interpret the data further from a geoarchaeological point of view with respect to the historical evolution of the local culture.

  17. Aarne Michaël Tallgren and the International Discussion on the Bronze Age of Russia

    Directory of Open Access Journals (Sweden)

    Timo Salminen

    2017-04-01

    Full Text Available This paper is on international scholarly discussion on the Bronze Age of Russia from 1908 until 1939, and in particular on the related role of the internationally renowned Finnish archaeologist Aarne Michaël Tallgren (1885–1945. How did a social network of researchers produce new interpretations and what were the key factors that distinguished the participants in the discussion? Was it a continuous process or a series of sudden changes? How did different ideological backgrounds influence the interpretations? In Western Europe, Tallgren’s most important interlocutors were Gero von Merhart, V Gordon Childe and Ellis H Minns, and in Russia V A Gorodcov and A A Spicyn. The paper is mainly based on correspondence between Tallgren and his colleagues.

  18. A 3-phase model for mixed columnar-equiaxed solidification in DC casting of bronze

    Science.gov (United States)

    Hao, J.; Grasser, M.; Wu, M.; Ludwig, A.; Riedle, J.; Eberle, R.

    2012-01-01

    A three-phase Eulerian approach is used to model the columnar-to-equiaxed transition (CET) during solidification in DC casting of technical bronze. The three phases are the melt, the solidifying columnar dendrites and the equiaxed grains. They are considered as spatially interpenetrating and interacting continua by solving the conservation equations of mass, momentum, species and enthalpy for all three phases. The so defined solidification model is applied to a binary CuSn6 DC casting process as a benchmark to demonstrate the model potentials. Two cases are studied: one considering only feeding flow and one including both feeding flow and equiaxed sedimentation. The simulated results of mixed columnar and equiaxed solidification are presented and discussed including the occurrence of CET, phase distribution, feeding flow, equiaxed sedimentation and their influence on macrosegregation.

  19. Performance evaluation of grid-enabled registration algorithms using bronze-standards

    CERN Document Server

    Glatard, T; Montagnat, J

    2006-01-01

    Evaluating registration algorithms is difficult due to the lack of gold standard in most clinical procedures. The bronze standard is a real-data based statistical method providing an alternative registration reference through a computationally intensive image database registration procedure. We propose in this paper an efficient implementation of this method through a grid-interfaced workflow enactor enabling the concurrent processing of hundreds of image registrations in a couple of hours only. The performances of two different grid infrastructures were compared. We computed the accuracy of 4 different rigid registration algorithms on longitudinal MRI images of brain tumors. Results showed an average subvoxel accuracy of 0.4 mm and 0.15 degrees in rotation.

  20. Combining X-ray based methods to study the protohistoric bronze technology in Western Iberia

    Energy Technology Data Exchange (ETDEWEB)

    Valério, P., E-mail: pvalerio@ctn.ist.utl.pt [Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior Técnico, Universidade de Lisboa, Campus Tecnológico e Nuclear, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS (Portugal); Silva, R.J.C., E-mail: rjcs@fct.unl.pt [CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Monte de Caparica (Portugal); Soares, A.M.M., E-mail: amsoares@ctn.ist.utl.pt [Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior Técnico, Universidade de Lisboa, Campus Tecnológico e Nuclear, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS (Portugal); Araújo, M.F., E-mail: faraujo@ctn.ist.utl.pt [Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior Técnico, Universidade de Lisboa, Campus Tecnológico e Nuclear, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS (Portugal); Gonçalves, A.P., E-mail: apg@ctn.ist.utl.pt [Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior Técnico, Universidade de Lisboa, Campus Tecnológico e Nuclear, Estrada Nacional 10 (km 139,7), 2695-066 Bobadela LRS (Portugal); Soares, R.M., E-mail: ruigusmao@hotmail.com [UNIARQ, Centro de Arqueologia da Universidade de Lisboa, Faculdade de Letras, Alameda da Universidade, 1600-214 Lisboa (Portugal)

    2015-09-01

    The Phoenician arrival at Iberian coastal regions had an actual influence on indigenous technology. A collection of coeval metallurgical remains and artefacts was studied by EDXRF, micro-EDXRF, SEM–EDS and XRD, to identify certain features of the production and utilisation of metal in protohistoric Western Iberia. The composition of artefacts indicates a prevalence of Cu–Sn alloys with low content of impurities (Pb, As, Sb and Fe) during Late Bronze and Early Iron Ages, while the composition of slags points to a smaller loss of copper in Phoenician smelting operations. Moreover, the amount of iron impurities in metal proved to be a helpful discriminator between indigenous and Phoenician-based metallurgies, showing that later alloys have higher amounts of iron. Besides, the indigenous alloys have higher tin contents that can probably be explained by the easier access to metal sources of local communities.

  1. Learners’ Mistakes or Professional Error – the Nordic Bronze Age ornaments

    DEFF Research Database (Denmark)

    Nørgaard, Heide Wrobel

    in practicing their trade. Within this study, visible production mistakes as well as errors in the decoration of the artefact were in focus. Such mistakes contain a large amount of information, as they can provide indications of the skill level of the craftsperson as well as on the social circumstances in which...... the item was crafted. In this paper, several examples will be compared to in order to illustrate the differences between professional mistakes and the hallmarks of apprenticeship. The aim is to differentiate between different kinds of apprenticeship solely based on visible mistakes. If such an approach......? Is this the result of different workshops, levels of crafting skills or perhaps even the incorporation of novice metalworkers? As part of a study on craft organization in the Nordic Bronze Age, several metal workshops were analyzed in relation to the skill of the craftsmen and the amount of time involved...

  2. Late Bronze Age in Alcáçova de Santarém (Portugal

    Directory of Open Access Journals (Sweden)

    Arruda, Ana Margarida

    2015-06-01

    Full Text Available The field work that took place in the restaurant area in Jardim das Portas do Sol (Alcáçova de Santarém recovered well-preserved archaeological layers dated to the Late Bronze Age, lying directly underneath the Iron Age phase. The excavation made it possible to collect an important set of ceramics that incorporate printed and incised decoration, which can be easily decoration related to the Cogotas 1 cultural background. Burnished decorations, with grooves on the inner surface and outer strips, are less common. The formal repertoire does not deviate from what is known about the Late Bronze Age in central and southern Iberian Peninsula. The data allow us to propose a chronology centered in the early 1st millennium BCE for this occupation.Durante los trabajos de campo, realizados en el área del restaurante del Jardim das Portas do Sol, se documentaron, por primera vez en Alcáçova de Santarém, niveles conservados del final de la Edad del Bronce, inmediatamente infrapuestos a los de la Edad del Hierro. Su excavación permitió recoger un conjunto de materiales cerámicos que incorpora varios fragmentos decorados por impresión e incisión, que pueden ser fácilmente relacionados con el universo cultural de Cogotas 1. Las decoraciones bruñidas con surcos en la superficie interna y con franjas al exterior son mucho menos frecuentes. El repertorio formal no difiere del conocido para el Bronce Final del centro y sur de la Península Ibérica. Los datos permiten proponer una cronologia del inicio del 1 milenio a.n.e. (siglo IX para esta ocupación.

  3. Dissecting mitochondrial dna variability of balearic populations from the bronze age to the current era.

    Science.gov (United States)

    Simón, Marc; Díaz, Nancy; Solórzano, Eduvigis; Montiel, Rafael; Francalacci, Paolo; Malgosa, Assumpció

    2017-01-01

    To determine ancient population influences on ancient and current Balearic populations and to reconstruct their mitochondrial DNA (mtDNA) gene pool evolution. We analyzed 239 individuals belonging to five archaeological populations from Majorca and Minorca, four dating to the transition between the Bronze Age and the Iron Age, and one Late Roman Majorcan population. Six additional individuals from Santa Teresa di Gallura from the Nuragic period were characterized and added to the existing samples from that culture to make comparisons with Talaiotic populations. We characterized the haplogroups of 138 individuals and obtained 69 sequences from mtDNA hypervariable region I. In the intra-island study, the apparent differences in social and funerary rites between two contiguous Majorcan necropolises were correlated with genetic characteristics. Also, the likely occurrence of consanguinity in a population with a very particular burial pattern was supported by genetic data. Despite the uniqueness of each necropolis, the global comparison of the five necropolises revealed no significant differences between them, or between ancient and modern populations from the islands. Ancient Balearics showed a similar mtDNA gene pool to Ancient Catalans, had a Near Eastern component, and showed continuity with European populations since at least the Bronze Age. We characterized five Balearic necropolises in the context of their geographic and cultural characteristics. The similarity between ancient Balearic and ancient Catalan gene pools reinforces their known historic interactions, while the lack of a consistent genetic continuity with Ancient Sardinians suggests that Talaiotic and Nuragic cultures arose in differentiated populations. Am. J. Hum. Biol. 29:e22883, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  4. Archaeological fieldwork in the Bronze Age site of Cerro de la Encina (Monachil, Granada

    Directory of Open Access Journals (Sweden)

    Aranda Jiménez, Gonzalo

    2005-06-01

    Full Text Available New archaeological fieldwork has been carried out from November 2003 to May 2004 in the Bronze Age site of Cerro de la Encina, due to the interest of the regional government of Andalusia in displaying the settlement for visitors. The aim of this fieldwork has been the systematic excavation of a large settlement area partially known thanks to the excavations developed at the beginning of 1980s. A first toccupation period belonging to the Argaric Culture has been documented, highlighting specially the funerary ritual characterized by individual inhumations located below dwellings. After a gap in the occupation of the settlement a new social group belonging to the Late Bronze Age Culture of Southeast of Spain inhabits the Cerro de la Encina.

    El interés de la Consejería de Cultura de la Junta de Andalucía por la musealización del yacimiento del Cerro de la Encina ha motivado el desarrollo de nuevas investigaciones arqueológicas cuya primera fase se ha desarrollado entre Noviembre de 2003 y Mayo de 2004. Los trabajos han consistido en la excavación sistemática de un área de poblado de grandes dimensiones parcialmente conocida por las investigaciones realizadas a principios de los años 80. Los resultados han sido del máximo interés documentándose un primer momento de ocupación perteneciente a la Cultura de El Argar en el que destaca su espectacular registro funerario integrado dentro de las áreas de habitación. Tras un periodo de abandono del yacimiento se produce una nueva ocupación correspondiente a una comunidad del Bronce Final del Sureste.

  5. Synthesis of hydrogen tungsten bronzes H{sub x}WO{sub 3} by reactive mechanical milling of hexagonal WO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Facundo J. [Centro Atomico Bariloche (CNEA, CONICET), Instituto Balseiro (UNCuyo), Av. Bustillo 9500, San Carlos de Bariloche (Argentina); Tonus, Florent; Bobet, Jean-Louis [Institut de Chimie de la Matiere Condensee de Bordeaux (ICMCB), CNRS (UPR 9048), Universite de Bordeaux I, 87 Avenue du Dr. A. Schweitzer, 33608 Pessac Cedex (France); Urretavizcaya, Guillermina, E-mail: urreta@cab.cnea.gov.a [Centro Atomico Bariloche (CNEA, CONICET), Instituto Balseiro (UNCuyo), Av. Bustillo 9500, San Carlos de Bariloche (Argentina)

    2010-04-16

    Recently, we have reported the formation of hydrogen tungsten bronzes by reactive mechanical milling monoclinic tungsten (VI) oxide under hydrogen atmosphere. In this work we report the milling of hexagonal WO{sub 3} under H{sub 2} atmosphere. Our main results are the structural transformation of the hexagonal oxide to the high temperature polymorph of WO{sub 3} with orthorhombic structure, and the formation of different hydrogen tungsten bronzes at distinct milling times. The bronzes seem to be formed from the orthorhombic oxide, and compared with the bronzes obtained by milling monoclinic WO{sub 3} are rather unstable after short exposure to air. The materials are characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and total hydrogen content determination.

  6. Food offerings, flowers, a bronze bucket and a waggon: a multidisciplinary approach regarding the Hallstatt princely grave from Prague-Letňany, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Kozáková, Radka; Kyselý, René; Trefný, M.; Drábková, K.; Kočár, Petr; Frolíková, Drahomíra; Kočárová, R.; Moravcová, Kamila

    -, - (2017) ISSN 1866-9557 Institutional support: RVO:67985912 Keywords : grave * meat offerings * pollen * bronze bucket * paint * infrared spectroscopy * xylotomic analysis Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 1.844, year: 2016

  7. Clarification of the Hashin-Shtrikman bounds on the effective elastic moduli of polycrystals with hexagonal, trigonal, and tetragonal symmetries

    Science.gov (United States)

    Watt, J.P.; Peselnick, L.

    1980-01-01

    Bounds on the effective elastic moduli of randomly oriented aggregates of hexagonal, trigonal, and tetragonal crystals are derived using the variational principles of Hashin and Shtrikman. The bounds are considerably narrower than the widely used Voigt and Reuss bounds. The Voigt-Reuss-Hill average lies within the Hashin-Shtrikman bounds in nearly all cases. Previous bounds of Peselnick and Meister are shown to be special cases of the present results.

  8. Structure of junctions of multiwalled carbon nanotubes with tetragonal cross section and flattened nanotubes revealed by electron-beam tomography

    Science.gov (United States)

    Nagano, Yuta; Kohno, Hideo

    2017-11-01

    Multiwalled carbon nanotubes with tetragonal cross section frequently form junctions with flattened multi-walled carbon nanotubes, a kind of carbon nanoribbon. The three-dimensional structure of the junctions is revealed by transmission-electron-microscopy-based tomography. Two types of junction, parallel and diagonal, are found. The formation mechanism of these two types of junction is discussed in terms of the origami mechanism that was previously proposed to explain the formation of carbon nanoribbons and nanotetrahedra.

  9. Pressure-induced change of the electronic state in the tetragonal phase of CaFe2As2

    Science.gov (United States)

    Sakaguchi, Yui; Ikeda, Shugo; Kuse, Tetsuji; Kobayashi, Hisao

    2014-07-01

    We have investigated the electronic states of single-crystal CaFe2As2 under hydrostatic pressure using 57Fe Mössbauer spectroscopy and magnetization measurements. The center shift and the quadrupole splitting were refined from observed 57Fe Mössbauer spectra using the single-crystalline sample under pressure at room temperature. A discontinuous decrease in the pressure dependence of the refined center shift was observed at 0.33 GPa without any anomaly in the pressure dependence of the refined quadrupole splitting, indicating a purely electronic state change in CaFe2As2 with a tetragonal structure. Such a change is shown to be reflected in the peak-like anomalies observed in the pressure dependences of the magnetic susceptibility at 0.26 GPa above 150 K. Our results reveal that this pressure-induced electronic state change suppresses the tetragonal-to-orthorhombic structural phase transition accompanied by an antiferromagnetic ordering. We further observed superconductivity in CaFe2As2 below ˜8 K around 0.33 GPa although our sample was not in a single phase at this pressure. These findings suggest that the electronic state change observed in CaFe2As2 with the tetragonal structure is relevant to the appearance of the pressure-induced superconductivity in AFe2As2.

  10. Synthesis of highly disperse tetragonal BaTiO3 nanoparticles with core–shell by a hydrothermal method

    Directory of Open Access Journals (Sweden)

    Jinhui Li

    2017-12-01

    Full Text Available In order to synthesize of high-dispersion and tetragonal BaTiO3 (BT nanoparticle, a hydrothermal method is used in a mixture of chloride metal sources and KOH with polyvinylpyrrolidone (PVP. The properties of BT–PVPs prepared by different reaction temperature and time are investigated via XRD, FE-SEM, DLS, FT-IR, and TEM to clarify the changes of the crystal phase, dispersion, and particle structure. The reaction is finished at 230 °C for 24 h and the critical reaction condition for that the crystal phase of the obtained BT particle changed from the cubic to the tetragonal is found to be 190 °C fixed in reaction time 24 h, and 9 h. During reaction the PVP on the BT surface decomposed to different form, and the PVP plays the role of dispersant in aqueous solution. By the hydrothermal condition of 230 °C for 24 h almost monodisperse BT–PVP with sizes of 83 nm and tetragonality (c/a of 1.0062 were synthesized. The structure of nanoparticle, core (BT–shell (PVP was investigated by FT-IR and direct observed by TEM and the mechanism of particle growth and dispersion was discussed.

  11. Thermodynamic theory of intrinsic finite-size effects in PbTiO3 nanocrystals. I. Nanoparticle size-dependent tetragonal phase stability

    Science.gov (United States)

    Akdogan, E. K.; Safari, A.

    2007-03-01

    We propose a phenomenological intrinsic finite-size effect model for single domain, mechanically free, and surface charge compensated ΔG-P ⃗s-ξ space, which describes the decrease in tetragonal phase stability with decreasing ξ rigorously.

  12. Suppression of electron correlations in the collapsed tetragonal phase of CaFe2As2 under ambient pressure demonstrated by As75 NMR/NQR measurements

    Science.gov (United States)

    Furukawa, Y.; Roy, B.; Ran, S.; Bud'ko, S. L.; Canfield, P. C.

    2014-03-01

    The static and the dynamic spin correlations in the low-temperature collapsed tetragonal and the high-temperature tetragonal phase in CaFe2As2 have been investigated by As75 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements. Through the temperature (T) dependence of the nuclear spin lattice relaxation rates (1/T1) and the Knight shifts, although stripe-type antiferromagnetic (AFM) spin correlations are realized in the high-temperature tetragonal phase, no trace of the AFM spin correlations can be found in the nonsuperconducting, low-temperature, collapsed tetragonal (cT) phase. Given that there is no magnetic broadening in As75 NMR spectra, together with the T-independent behavior of magnetic susceptibility χ and the T dependence of 1/T1Tχ, we conclude that Fe spin correlations are completely quenched statically and dynamically in the nonsuperconducting cT phase in CaFe2As2.

  13. Crystallization behavior of tetragonal ZrO{sub 2} prepared in a silica bath

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Moo-Chin, E-mail: mcwang@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan (China); Huang, Hung-Jui [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan (China)

    2013-09-10

    Highlights: ► The activation energy of t-ZrO{sub 2} crystallization calculated by the JMA equation is 643.0 ± 13.9 kJ·mol{sup −1}. ► The growth morphology parameter (n) and crystallization mechanism index (m) are approximated as 3.0. ► Bulk nucleation is dominant in the t-ZrO{sub 2} crystallization process, and has a spherical-like morphology. ► The TEM microstructure reveals that the t-ZrO{sub 2} crystallites have a spherical-like morphology. - Abstract: The synthesis of zirconia (ZrO{sub 2}) precursor powders by a co-precipitation process is studied in this work, using a silica bath prepared at 348 K and pH = 7, with 10 min mixing using zirconium (IV) nitrate and tetraethylorthosilicate (TEOS, Si(OC{sub 2}H{sub 5}){sub 4}) as the starting materials. The XRD result show that only a single phase of tetragonal ZrO{sub 2} (t-ZrO{sub 2}) appears when the freeze dried precursor powders are calcined between 1173 and 1473 K for 120 min. The activation energy of t-ZrO{sub 2} crystallization, as calculated by the Johnson–Mehl–Avrami (JMA) equation, is 643.0 ± 13.9 kJ/mol. The growth morphology parameter (n) and crystallization mechanism index (m) are approximated as 3.0, which indicates that bulk nucleation is dominant in the t-ZrO{sub 2} crystallization process, and that the material has a plate-like morphology.

  14. Crystal structure refinements of tetragonal (OH,F)-rich spessartine and henritermierite garnets

    Energy Technology Data Exchange (ETDEWEB)

    Antao, Sytle M.; Cruickshank, Laura A.

    2018-01-30

    Cubic garnet (space group Ia\\overline 3 d) has the general formulaX3Y2Z3O12, whereX,YandZare cation sites. In the tetragonal garnet (space groupI41/acd), the corresponding cation sites areX1 andX2,Y, andZ1 andZ2. In both space groups only theYsite is the same. The crystal chemistry of a tetragonal (OH,F)-rich spessartine sample from Tongbei, near Yunxiao, Fujian Province, China, with compositionX(Mn2.82Fe^{2+}_{0.14}Ca0.04)Σ3Y{Al1.95Fe^{3+}_{0.05}}Σ2Z[(SiO4)2.61(O4H4)0.28(F4)0.11]Σ3(Sps94Alm5Grs1) was studied with single-crystal X-ray diffraction and space groupI41/acd. The deviation of the unit-cell parameters from cubic symmetry is small [a= 11.64463(1),c= 11.65481 (2) Å,c/a= 1.0009]. Point analyses and back-scattered electron images, obtained by electron-probe microanalysis, indicate a homogeneous composition. TheZ2 site is fully occupied, but theZ1 site contains vacancies. The occupiedZ1 andZ2 sites with Si atoms are surrounded by four O atoms, as in anhydrous cubic garnets. Pairs of split sites are O1 with F11 and O2 with O22. When theZ1 site is vacant, a larger [(O2H2)F2] tetrahedron is formed by two OH and two F anions in the O22 and F11 sites, respectively. This [(O2

  15. In situ study of the Porticello Bronzes by portable X-ray fluorescence and laser-induced breakdown spectroscopy

    Science.gov (United States)

    Ferretti, M.; Cristoforetti, G.; Legnaioli, S.; Palleschi, V.; Salvetti, A.; Tognoni, E.; Console, E.; Palaia, P.

    2007-12-01

    This paper reports the results of a measurement campaign performed at the National Museum of Magna Grecia in Reggio Calabria (Italy). Portable X-Ray Fluorescence (XRF) and Laser-Induced Breakdown Spectroscopy (LIBS) instrumentation allowed in situ analysis of several bronze pieces belonging to the group of the so-called Porticello Bronzes. The find occurred at sea, off the village of Porticello (Reggio Calabria) in 1969 and consists of a number of fragments, including a bearded head, pertaining to at least two statues. The use of X-Ray Fluorescence and Laser-Induced Breakdown Spectroscopy techniques allowed for a classification of the fragments according to their elemental composition. The fragments appear to belong to at least two different statues; although, in general, the compositional classification agrees well with the stylistic analysis of the fragments, significant improvements with respect to previous achievements emerge from the joint results of the two techniques used.

  16. Avaliação das constantes elásticas de bronzes vazados com alto teor em estanho

    OpenAIRE

    Marreiros, Ricardo Miguel Martins

    2014-01-01

    Este estudo pretendeu caracterizar as constantes elásticas de bronzes com alto teor em estanho e, em particular, da fase intermetálica delta (~32 wt.% Sn) à temperatura ambiente. Esta caracterização é importante para a previsão das propriedades acústicas dos sinos, pelo que especial atenção foi também dada à composição média das ligas Cu-Sn usadas na fundição sineira. Estes bronzes, devido ao caráter frágil da fase delta, não são processados termo-mecanicamente, apresentando-se na condição de...

  17. Dynamic secondary ion mass spectrometry and X-ray photoelectron spectroscopy on artistic bronze and copper artificial patinas

    Science.gov (United States)

    Balta, I. Z.; Pederzoli, S.; Iacob, E.; Bersani, M.

    2009-04-01

    To prevent the natural processes of decay and to develop and improve the treatments of conservation and restoration of artistic bronzes meaning statues and sculptures, it is important understanding the patination processes and the knowledge of artificially corroded surfaces. Chemical and physical characterization of artificial patinas obtained on artistic bronzes and coppers by using the 19th century Western traditional patination techniques and recipes by means of SEM-EDS, light microscopy and ATR/FT-IR has been done in previous studies [I.Z. Balta, L. Robbiola, Characterization of artificial black patinas on artistic cast bronze and pure copper by using SEM-EDS and light microscopy, in: Proceedings of the 13th European Microscopy Congress, 22-27 August 2004, Antwerp, Belgium, EMC 2004 CD-Rom Conference Preprints; I.Z. Balta, L. Robbiola, Traditional artificial artistic bronze and copper patinas—an investigation by SEM-EDS and ATR/FT-IR, in: Proceedings of the 8th International Conference on Non Destructive Investigations and Microanalysis for the Diagnostics and Conservation of the Cultural and Environmental Heritage, 15-19 May 2005, Lecce, Italy, ART'05 CD-Rom Conference Preprints]. Differences in morphology (structure, thickness, porosity, adherence, compactity, uniformity, homogeneity) and also in composition, on both artistic cast bronze and pure copper patinas, were clearly evidenced. Further in-depth investigation is required to be carried out in order to better understand the patinas mechanisms of formation and the layers kinetics of growth. The elemental and chemical analysis, either on a surface monolayer or in a depth profile, by using the Secondary Ion Mass Spectrometry (SIMS) and X-ray Photoelectron Spectroscopy (XPS) techniques, can provide this kind of information, unique at trace-level sensitivity. SIMS has proved to be a suitable analytical technique for analyzing small amounts of material with high atomic sensitivity (ppm or even ppb) and high

  18. In situ study of the Porticello Bronzes by portable X-ray fluorescence and laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, M. [Istituto per le Tecnologie Applicate ai Beni Culturali, Via Salaria, km 29.300, c.p.10, 00016 Monterotondo St. - Roma (Italy); Cristoforetti, G.; Legnaioli, S. [Applied Laser Spectroscopy Laboratory, Istituto per i Processi Chimico Fisici del CNR, Area di Ricerca di Pisa, Via G.Moruzzi, 1-56124 Pisa (Italy); Palleschi, V. [Applied Laser Spectroscopy Laboratory, Istituto per i Processi Chimico Fisici del CNR, Area di Ricerca di Pisa, Via G.Moruzzi, 1-56124 Pisa (Italy); Salvetti, A.; Tognoni, E. [Applied Laser Spectroscopy Laboratory, Istituto per i Processi Chimico Fisici del CNR, Area di Ricerca di Pisa, Via G.Moruzzi, 1-56124 Pisa (Italy); Console, E. [T.E.A. s.a.s., Via Luigi Pascali, 23/25-88100 Catanzaro (Italy)], E-mail: elena@teacz.191.it; Palaia, P. [T.E.A. s.a.s., Via Luigi Pascali, 23/25-88100 Catanzaro (Italy)

    2007-12-15

    This paper reports the results of a measurement campaign performed at the National Museum of Magna Grecia in Reggio Calabria (Italy). Portable X-Ray Fluorescence (XRF) and Laser-Induced Breakdown Spectroscopy (LIBS) instrumentation allowed in situ analysis of several bronze pieces belonging to the group of the so-called Porticello Bronzes. The find occurred at sea, off the village of Porticello (Reggio Calabria) in 1969 and consists of a number of fragments, including a bearded head, pertaining to at least two statues. The use of X-Ray Fluorescence and Laser-Induced Breakdown Spectroscopy techniques allowed for a classification of the fragments according to their elemental composition. The fragments appear to belong to at least two different statues; although, in general, the compositional classification agrees well with the stylistic analysis of the fragments, significant improvements with respect to previous achievements emerge from the joint results of the two techniques used.

  19. Application of X-Ray and Neutron Tomography to Study Antique Greek Bronze Coins with a High Lead Content

    Science.gov (United States)

    Griesser, M.; Traum, R.; Vondrovec, K.; Vontobel, P.; Lehmann, E. H.

    2012-07-01

    Highly leaded bronze coins of the Coin Cabinet of the Kunsthistorisches Museum (KHM) show progressive corrosion as a result of unfavourable storage conditions within historic wooden cases. In connection to a research project concerning the preservation and conservation of the antique coins the causes for the sometimes severe corrosion were studied by different analytical techniques. Radiography and tomography investigations using neutrons and X-rays were performed at the Paul Scherrer Institute, i.e. the enrichment of lead in the interior of the objects was studied in a nondestructive manner. The tomography results obtained show that in addition to the lead rich areas on the obverse and reverse of the coins (often already clearly visible on the surface due to the formation of white corrosion products) a varying number of lead containing inclusions could be detected within the antique bronze coins. In addition, some information on their casting technique could be gained.

  20. Magnetization and Inter-Filament Contact in HEP and ITER Bronze-Route Nb(3)Sn Wires

    CERN Document Server

    Bordini, B; Devred, A; Richter, D; Bessette, D; Jewell, M; Bottura, L

    2011-01-01

    Magnetization measurements are relevant tests for the characterization of superconductors. Practically they are the only measurements that allow estimating the critical current density at low fields of low temperature superconductors, the effective filament size and the hysteresis losses. For this purpose CERN, in collaboration with the University of Geneva, has carried out magnetization measurements on five types of Nb(3)Sn wires: three bronze route strands used in the ITER project; one Powder In Tube (PIT) and one Internal Tin (IT) wires used for developing next generation accelerator magnets. The field dependent magnetization has been determined using three setups: a Vibrating Sample Magnetometer (VSM), a Superconducting Quantum Interference Device (SQUID) and a special system used for the production control of LHC strands. Samples of different lengths have been tested to check the different coupling between the filaments. Unexpectedly, it was found that the magnetization of the tested bronze wires was str...

  1. Magnetization and Inter-Filament Contact in HEP and ITER Bronze-Route Nb3Sn Wires

    CERN Document Server

    Bordini, B; Bottura, L; Devred, A; Jewell, M; Richter, D; Senatore, C

    2011-01-01

    Magnetization measurements are relevant tests for the characterization of superconductors. Practically they are the only measurements that allow estimating the critical current density at low fields of low temperature superconductors, the effective filament size and the hysteresis losses. For this purpose CERN, in collaboration with the University of Geneva, has carried out magnetization measurements on five types of Nb3Sn wires: three bronze route strands used in the ITER project; one Powder In Tube (PIT) and one Internal Tin (IT) wires used for developing next generation accelerator magnets. The field dependent magnetization has been determined using three set-ups: a Vibrating Sample Magnetometer (VSM), a Superconducting Quantum Interference Device (SQUID) and a special system used for the production control of LHC strands. Samples of different lengths have been tested to check the different coupling between the filaments. Unexpectedly, it was found that the magnetization of the tested bronze wires was stro...

  2. Creativity in the Bronze Age: bringing archaeological research into contemporary craft teaching and learning through a live project

    OpenAIRE

    Persad, Rachel; Sofaer, Joanna

    2016-01-01

    The CinBA Live Project sought to engage students of contemporary craft courses in the UK with Bronze Age creativity. We aimed to explore the ways in which the creativity inherent in prehistoric craft may be used as inspiration in contemporary making. It simultaneously offered institutions a unique opportunity to offer a practice-led, research-based live project which was distinct to those generally known to be available to art and design institutions. It offered a different experience within ...

  3. Analysis of the Causes of Cracks in a Thick-Walled Bush Made of Die-Cast Aluminum Bronze

    Directory of Open Access Journals (Sweden)

    Pisarek B.P.

    2016-12-01

    Full Text Available For the die casting conditions of aluminium bronzes assumed based on the literature data, a thick-walled bush was cast, made of complex aluminium bronze (Cu-Al-Fe-Ni-Cr. After the cast was removed from the mould, cracks were observed inside it. In order to identify the stage in the technological production process at which, potentially, the formation of stresses damaging the continuity of the microstructure created in the cast was possible (hot cracking and/or cold cracking, a computer simulation was performed. The article presents the results of the computer simulation of the process of casting the material into the gravity die as well as solidifying and cooling of the cast in the shape of a thick-walled bush. The simulation was performed with the use of the MAGMA5 program and by application of the CuAl10Ni5,5Fe4,5 alloy from the MAGMA5 program database. The results were compared with the location of the defects identified in the actual cast. As a result of the simulation of the die-casting process of this bush, potential regions were identified where significant principal stresses accumulate, which can cause local hot and cold cracking. Until now, no research has been made of die-cast aluminium bronzes with a Cr addition. Correlating the results of the computer simulation validated by the analysis of the actual cast made it possible to clearly determine the critical regions in the cast exposed to cracking and point to the causes of its occurrence. Proposals of changes in the bush die casting process were elaborated, in order to avoid hot tearing and cold cracking. The article discusses the results of preliminary tests being a prologue to the optimization of the die-casting process parameters of complex aluminium bronze thick-walled bushs.

  4. Neutron-based analyses of three Bronze Age metal objects: a closer look at the Buggenum, Jutphaas and Escharen artefacts

    OpenAIRE

    POSTMA HANS; AMKREUTZ LUC; FONTIJN D.; Kamermans, H.; Kockelmann, W.; SCHILLEBEECKX PETER; VISSER DIRK

    2017-01-01

    Three important Bronze Age copper-alloy artefacts from the permanent exhibition of the National Museum of Antiquity in Leiden (NL) have been studied by neutron-based methods. These artefacts are known as the Buggenum sword, the Jutphaas dirk, and the Escharen double axe. All three objects have been studied with neutron resonance capture analysis (NRCA), a non-destructive method to determine the bulk elemental compositions. The Buggenum sword is also studied with time-of-flight neutron diffrac...

  5. Bones from the labyrinth: Faunal evidence for management and consumption of animals at Neolithic and Bronze Age Knossos, Crete.

    OpenAIRE

    Isaakidou, V.

    2005-01-01

    Animals feature extensively in the iconography and written records of Bronze Age Crete, and in archaeological debates ranging from initial colonisation in the 7th millennium BC, through expansion of settlement across the island in the 4th-3rd millennia, to surplus mobilisation and feasting by the 2nd millennium palaces. To date, however, faunal remains---the most widely available evidence for human use of animals---have been neglected: detailed reports of large assemblages are non-existent an...

  6. Tooth wear pattern analysis in a sample of Italian Early Bronze Age population. Proposal of a 3-D sampling sequence.

    Science.gov (United States)

    Masotti, Sabrina; Bogdanic, Nika; Arnaud, Julie; Cervellati, Franco; Gualdi-Russo, Emanuela

    2017-02-01

    The purpose of this study was to assess the prevalence, distribution and intensity of tooth wear in a sample of an ancient Italian population in order to explain the pattern in terms of dietary habits and/or non-dietary tooth-use behaviors during the Early Bronze Age, with a focus on possible age-group and sex differences. Well-preserved permanent teeth of individuals from the Bronze Age site of Ballabio (Lecco) in northern Italy were examined for tooth wear by different methods. Eight 3D models of teeth at increasing severity of wear were created. In total, 357 permanent teeth belonging to male and female individuals were included in the study. Dental wear was present in 96.6% of the total sample. Males showed significantly greater levels of wear than females in the mandibular teeth. Both sexes exhibited a significantly different wear direction between the anterior (oblique and flat) and posterior (oblique and concave) teeth. Significant age differences were observed in the direction and level of wear in the incisors, canines and premolars, with higher wear in the older group. Complete and rotatable virtual 3D images of different wear patterns are proposed. The findings of the present study confirm the data from archaeological studies on this site and on northern Italian habits during the Early Bronze Age suggesting a diet rich in vegetables. The observed wear patterns can be related both to the diet of this Bronze age population, based on hard and abrasive food requiring vigorous mastication, and to sex differences in cultural practices. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. The maternal genetic make-up of the Iberian Peninsula between the Neolithic and the Early Bronze Age

    OpenAIRE

    Szécsényi-Nagy, Anna; Roth, Christina; Brandt, Guido; Rihuete-Herrada, Cristina; Tejedor-Rodríguez, Cristina; Held, Petra; García-Martínez-de-Lagrán, Íñigo; Arcusa Magallón, Héctor; Zesch, Stephanie; Knipper, Corina; Bánffy, Eszter; Friederich, Susanne; Meller, Harald; Bueno Ramírez, Primitiva; Barroso Bermejo, Rosa

    2017-01-01

    Agriculture first reached the Iberian Peninsula around 5700 BCE. However, little is known about the genetic structure and changes of prehistoric populations in different geographic areas of Iberia. In our study, we focus on the maternal genetic makeup of the Neolithic (~ 5500–3000 BCE), Chalcolithic (~ 3000–2200 BCE) and Early Bronze Age (~ 2200–1500 BCE). We report ancient mitochondrial DNA results of 213 individuals (151 HVS-I sequences) from the northeast, central, southeast and southwest ...

  8. Bronze Age metal artefacts found on Cyprus - metal from Anatolia and the Western Mediterranean

    Directory of Open Access Journals (Sweden)

    Stos-Gale, Zofia A.

    2010-12-01

    Full Text Available Hundreds of Bronze Age metal artefacts excavated on archaeological sites in Cyprus have been analysed for their lead isotope and elemental composition in the Isotrace Laboratory, University of Oxford, in the years 1982-2002. In parallel, but in particular after 1995, hundreds of samples of minerals and slags collected from the mines and smelting sites around the Troodos Mountains were also analysed. Most of the results were published in various articles over the years, but the interpretation of some of the lead isotope data needs a current revision in view of new research conducted in Spain, Sardinia and southern France. It has been known that the lead isotope data for metal artefacts from the Cypriot Bronze Age sites shows that not all of the copper is consistent with origin from the Cypriot ores. In addition, the lead and silver artefacts found there must have been imported, because there are no lead or silver ores on Cyprus. The re-evaluation of the data shows that about 11 % of the analysed metal artefacts are consistent with the origin from the deposits in the Aegean and Turkey, while about 14 % with sources in the Western Mediterranean. This paper discusses in detail the current interpretation of the research into the sources of imported metal found in the Bronze Age context on Cyprus.

    Cientos de objetos de metal de la Edad del Bronce excavados en yacimientos de Chipre han sido analizados para conocer su composición elemental y sus isótopos de plomo en el Isotrace Laboratory de la Universidad de Oxford entre los años 1982 y 2002. Especialmente con posterioridad a 1995 cientos de muestras de minerales y escorias recogidas de minas y sitios de reducción de minerales localizadas en el entorno de las montañas de Troodos también fueron analizadas. La mayoría de los resultados fueron publicados en varios artículos a lo largo del tiempo, pero la interpretación de algunos análisis de isótopos de plomo necesitan de una revisión a

  9. The Bronze Age in the Northwestern of Iberian Peninsula: an analysis from funerary practices

    Directory of Open Access Journals (Sweden)

    Bettencourt, Ana M. S.

    2010-06-01

    Full Text Available From the analysis of the funerary practices and of their integration in the different chronological-cultural contexts where they develop, the author works out a new interpretation of the mechanism of negotiation of power and the promotion of social identity through the Bronze Age of the NW Iberian Peninsula. When studying an area so wide she distinguishes two great trends in the type and distribution of the funerary architectures throughout the Bronze Age that she associates with different ways of interaction with, and perception of, the world. Thus, she argues that the necropolises of “cloudy” tombs (cists without tumuli, plain graves and pits, located in areas of great agricultural potential and close to the settlements, may have been constructed by sedentary communities, very involved in agricultural activities, with a great sense of territoriality and a great control over, and deep knowledge of, the territory. On the other hand the communities involved with mountain landscapes, eventually more related to cattle and with ways of life that would imply greater mobility, were responsible for the construction of more visible funerary structures, such as small tumuli of megalithic tradition, located away from the settlements. In relation to the social role of the corpse, the author argues for the Early Bronze Age, that, the occupation of new territories, the emergence of a new form of community interaction with the environment and the emergence of new mechanisms of power and legitimacy of the territory were materialized in burial practices and in the social role of some corpses, in copper and gold grave goods. This social role was represented in old and new places. From the Middle Bronze Age she assumes that the corpse loses importance in collective terms and that death becomes more familiar. The new settings of power negotiation and social identity are transferred to other contexts of action more connected with the sphere of the living

  10. A family of rare earth molybdenum bronzes: Oxides consisting of periodic arrays of interacting magnetic units

    Energy Technology Data Exchange (ETDEWEB)

    Schneemeyer, L.F. [Department of Chemistry, Montclair State University, Montclair, NJ 07043 (United States); Siegrist, T., E-mail: tsiegrist@fsu.edu [Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL 32310 (United States); National High Magnetic Field Laboratory, Tallahassee, FL 32310 (United States); Besara, T. [National High Magnetic Field Laboratory, Tallahassee, FL 32310 (United States); Lundberg, M. [Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL 32310 (United States); National High Magnetic Field Laboratory, Tallahassee, FL 32310 (United States); Sun, J. [Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL 32310 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6056 (United States); Singh, D.J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6056 (United States)

    2015-07-15

    The family of rare earth molybdenum bronzes, reduced ternary molybdates of composition LnMo{sub 16}O{sub 44,} was synthesized and a detailed structural study carried out. Bond valence sum (BVS) calculations clearly show that the molybdenum ions in tetrahedral coordination are hexavalent while the electron count in the primitive unit cell is odd. Yet, measurements show that the phases are semiconductors. The temperature dependence of the magnetic susceptibility of samples containing several different rare earth elements was measured. These measurements verified the presence of a 6.5 K magnetic phase transition not arising from the rare earth constituent, but likely associated with the unique isolated ReO{sub 3}-type Mo{sub 8}O{sub 36} structural subunits in this phase. To better understand the behavior of these materials, electronic structure calculations were performed within density functional theory. Results suggest a magnetic state in which these structural moieties have an internal ferromagnetic arrangement, with small ~1/8 μ{sub B} moments on each Mo. We suggest that the Mo{sub 8}O{sub 36} units behave like pseudoatoms with spin 1/2 derived from a single hole distributed over the eight Mo atoms that are strongly hybridized with the O atoms of the subunit. Interestingly, while the compound is antiferromagnetic, our calculations suggest that a field-stabilized ferromagnetic state, if achievable, will be a narrow band half-metal. - Graphical abstract: LnMo{sub 16}O{sub 44} phases comprise corner sharing tetrahedral and octahedral molybdenum ions. The MoO{sub 6} octahedra form Mo{sub 8}O{sub 36} units that are well separated and act like pseudo-atoms, accommodating 11 electrons each. - Highlights: • Single crystal X-ray diffraction refinements of LnMo{sub 16}O{sub 44} single crystals for Ln=Ce, Pr, Nd, Tb, Dy and Ho. • DFT calculations based on LaMo{sub 16}O{sub 44}. • [Mo{sub 8}O{sub 36}] units behaving as superatoms with a net magnetic moment of 1 µ

  11. Alloy characterization of a 7th Century BC archeological bronze vase — Overcoming patina constraints using Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Manso, M. [Laboratório de Instrumentação, Engenharia Biomédica e Fisica da Radiação (LIBPhys-UNL), Departamento de Fisica, Faculdade de Ciências e Tecnologias, Universidade Nova de Lisboa, 2829-516 Monte da Caparica (Portugal); Faculdade de Belas-Artes da Universidade de Lisboa, Largo da Academia Nacional de Belas-Artes, 1249-058 Lisboa (Portugal); Schiavon, N. [Hercules Laboratory, University of Évora, Palácio do Vimioso,Largo Marquês de Marialva 8, 7000-809 Évora Portugal (Portugal); Queralt, I. [Laboratory of X-ray Analytical Applications, Institute of Earth Sciences Jaume Almera, CSIC, Solé Sabaris s/n, 08028 Barcelona (Spain); Arruda, A.M. [Centro de Arqueologia da Universidade de Lisboa (UNIARQ), Alameda da Universidade, 1600-214 Lisboa (Portugal); Sampaio, J.M. [BioISI — Biosystems & Integrative Sciences Institute, Faculdade de Ciências da Universidade de Lisboa (Portugal); Brunetti, A., E-mail: brunetti@uniss.it [Department of Political Science and Communication, University of Sassari, Via Piandanna 2, 07100 Sassari (Italy)

    2015-05-01

    In this work we evaluate the composition of a bronze alloy using X-ray fluorescence spectrometry (XRF) and Monte Carlo (MC) simulations. For this purpose, a 7th Century BC archeological vase from the SW Iberian Peninsula, displaying a well formed corrosion patina was analyzed by means of a portable X-ray fluorescence spectrometer. Realistic MC simulations of the experimental setup were performed with the XRMC code package which is based on an intensive use of variance-reduction techniques and uses XRAYLIB a constantly updated X-ray library of atomic data. A single layer model was applied for simulating XRF of polished/pristine bronze whereas a two-or-three-layer model was developed for bronze covered respectively by a corrosion patina alone or coupled with a superficial soil derived crust. These simulations took into account corrosion (cerussite (PbCO{sub 3}), cuprite (Cu{sub 2}O), malachite (Cu{sub 2}CO{sub 3}(OH){sub 2}), litharge (PbO)) and soil derived products (goethite (FeO(OH)) and quartz (SiO{sub 2})) identified by means of X-ray diffraction and Raman micro analytical techniques. Results confirm previous research indicating that the XRF/Monte Carlo protocol is well suited when a two-layered model is considered, whereas in areas where the patina + soil derived products' crust is too thick, X-rays from the alloy substrate are not able to exit the sample. Quantitative results based on MC simulations indicate that the vase is made of a lead–bronze alloy: Mn (0.2%), Fe (1.0%), Cu (81.8%), As (0.5%), Ag (0.6%), Sn (8.0%) and Pb (8.0%). - Highlights: • We study an archeological bronze vase with patina corrosion using XRF spectrometry. • The experimental setup is modeled using Monte Carlo (MC) simulations. • Combining MC simulations with XRF it is possible to derive concentrations. • We demonstrated that this is possible without removing the patina.

  12. Direct observation of the core/double-shell architecture of intense dual-mode luminescent tetragonal bipyramidal nanophosphors.

    Science.gov (United States)

    Kim, Su Yeon; Jeong, Jong Seok; Mkhoyan, K Andre; Jang, Ho Seong

    2016-05-21

    Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors-Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4-and the C/D-S structure has been proved by extensive scanning transmission electron microscopy (STEM) analysis. Colloidal LiYF4:Ce,Tb nanophosphors with a tetragonal bipyramidal shape are synthesized for the first time and they show intense DC green light via energy transfer from Ce(3+) to Tb(3+) under illumination with ultraviolet (UV) light. The LiYF4:Ce,Tb nanophosphors show 65 times higher photoluminescence intensity than LiYF4:Tb nanophosphors under illumination with UV light and the LiYF4:Ce,Tb is adapted into a luminescent shell of the tetragonal bipyramidal C/D-S nanophosphors. The formation of the DC shell on the core significantly enhances UC luminescence from the UC core under irradiation of near infrared light and concurrently generates DC luminescence from the core/shell nanophosphors under UV light. Coating with an inert inorganic shell further enhances the UC-DC dual-mode luminescence by suppressing the surface quenching effect. The C/D-S nanophosphors show 3.8% UC quantum efficiency (QE) at 239 W cm(-2) and 73.0 ± 0.1% DC QE. The designed C/D-S architecture in tetragonal bipyramidal nanophosphors is rigorously verified by an energy dispersive X-ray spectroscopy (EDX) analysis, with the assistance of line profile simulation, using an aberration-corrected scanning transmission electron microscope equipped with a high-efficiency EDX. The feasibility of these C/D-S nanophosphors for transparent display devices is also considered.

  13. Stratospheric Ozone destruction by the Bronze-Age Minoan eruption (Santorini Volcano, Greece).

    Science.gov (United States)

    Cadoux, Anita; Scaillet, Bruno; Bekki, Slimane; Oppenheimer, Clive; Druitt, Timothy H

    2015-07-24

    The role of volcanogenic halogen-bearing (i.e. chlorine and bromine) compounds in stratospheric ozone chemistry and climate forcing is poorly constrained. While the 1991 eruption of Pinatubo resulted in stratospheric ozone loss, it was due to heterogeneous chemistry on volcanic sulfate aerosols involving chlorine of anthropogenic rather than volcanogenic origin, since co-erupted chlorine was scavenged within the plume. Therefore, it is not known what effect volcanism had on ozone in pre-industrial times, nor what will be its role on future atmospheres with reduced anthropogenic halogens present. By combining petrologic constraints on eruption volatile yields with a global atmospheric chemistry-transport model, we show here that the Bronze-Age 'Minoan' eruption of Santorini Volcano released far more halogens than sulfur and that, even if only 2% of these halogens reached the stratosphere, it would have resulted in strong global ozone depletion. The model predicts reductions in ozone columns of 20 to >90% at Northern high latitudes and an ozone recovery taking up to a decade. Our findings emphasise the significance of volcanic halogens for stratosphere chemistry and suggest that modelling of past and future volcanic impacts on Earth's ozone, climate and ecosystems should systematically consider volcanic halogen emissions in addition to sulfur emissions.

  14. Holes in teeth - Dental caries in Neolithic and Early Bronze Age populations in Central Germany.

    Science.gov (United States)

    Nicklisch, Nicole; Ganslmeier, Robert; Siebert, Angelina; Friederich, Susanne; Meller, Harald; Alt, Kurt W

    2016-01-01

    This study provides diachronic insight into the epidemiology of carious defects in teeth of Neolithic and Early Bronze Age populations in Central Germany over a period of 4000 years. The data were retrieved from skeletal remains uncovered at 21 sites throughout the Middle Elbe-Saale region (MES), comprising a total of 494 individuals with preserved teeth. The data generated were examined for age- and sex-related differences in order to gain information about the dietary habits and socio-economic structures of the period with the goal of identifying potential diachronic changes. The results indicated that dietary habits changed over the course of the Neolithic period: the prevalence of caries significantly decreased between the Early and Late Neolithic. The adults from the Early Neolithic sample, particularly those from the LBK bore the highest rate of caries. This highlights the essential importance of cereals in the diet of the early farmers in the Middle Elbe-Saale region. As time went on, meat and dairy products became more and more important, which had a positive impact on dental health. The data also show sex-specific differences: women were more often affected by caries than men and female jaws also generally exhibited greater numbers of carious teeth than their male counterparts. Dental health is a reflection of both biological factors and of economic and sociocultural structures. Copyright © 2015 Elsevier GmbH. All rights reserved.

  15. Questions about graphite pottery of Late Bronze and Iron Age I in the Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Barroso Bermejo, Rosa

    2002-06-01

    Full Text Available Graphite pottery is an increasingly frequent element in the contexts of the Iberian Bronze-Iron Ages. This paper summarises its current dispersal, centred on the eastern Iberian Peninsula, especially in the interior, so that it becomes a good indicator of the relationships established on the Meseta during this period. Most graphite pots are pieces of medium and small size, of good quality, dark colour, non-exclusive shapes and a decoration that allows us to distinguish six different variants. Only the technical aspects link them with the French examples, which have a similar chronology.

    Las cerámicas grafitadas son un elemento cada vez más frecuente en los contextos del Bronce-Hierro peninsular. En este artículo se recoge su dispersión actual, centrada en la vertiente oriental y de gran profusión en las tierras del interior hasta el punto de convertirse en un buen indicador de las relaciones mantenidas por la Meseta durante este periodo. Mayoritariamente estamos ante piezas de mediano y pequeño tamaño, de buena calidad, color oscuro, perfiles no exclusivos y una decoración que permite diferenciar seis variantes diferentes. Sólo la importancia técnica que suponen sigue ligándolas a las francesas con las que tienen entre otras cosas una cronología similar.

  16. Leather material found on a 6th B.C. Chinese bronze sword: A technical study

    Science.gov (United States)

    Luo, Wugan; Si, Yi; Wang, Hongmin; Qin, Ying; Huang, Fengchun; Wang, Changsui

    2011-09-01

    During July to November, 2006, an important archaeological excavation was conducted in Yun country, Hubei province, southern China. Chinese archaeologists found some remnant of leather materials, covered with red pigments, on a 6th century B.C. Chinese bronze sword. To understand the technology/ies that may have been utilized for manufacturing the leathers, a combined of Raman spectroscopy, FT-IR and XRF was thus applied to the remnant of leather materials. Raman analyses showed that red pigment on the leather was cinnabar (HgS). FT-IR and XRF analyses indicated that the content of some elements, such as Ca (existing as CaCO 3) and Fe (existing as Fe 2O 3), were much higher than those in the surrounding grave soil. The results inferred an application of lime depilation and retting, and the Fe-Al compound salt as tanning agent. And it was furthermore implicated that the Fe-Al salt tanning technique had been developed in the middle and late Spring and Autumn Period of China.

  17. Post-transcriptional regulation of expression of the Bronze2 gene of Zea mays L.

    Science.gov (United States)

    Pairoba, Claudio F; Walbot, Virginia

    2003-09-01

    The glutathione S-transferase encoded by Bronze2 performs the last genetically defined step in maize anthocyanin biosynthesis, being required for pigment sequestration into vacuoles. The Bz2 primary transcript contains a single intron; in maize leaves both spliced and unspliced Bz2 transcripts are usually present and are predicted to encode 26 and 14 kDa proteins, respectively. To increase understanding of the role and regulation of Bz2 transcript splicing, we examined Bz2 expression during development in transgenic maize plants expressing a 35S:Bz2 (35S:mycBz2i) gene and, by transient expression analysis, in Black Mexican Sweet maize protoplasts. We show here that the gene is expressed in diverse tissues that lack functional copies of one or both transcription factors regulating anthocyanin synthesis, that transcript levels are much higher when the R/B plus C1/Pl transcription factors are present, and that the splicing decision depends on local sequence context. The predicted 14 kDa protein was never detected indicating that unspliced transcripts are likely to be non-coding. The native 26 kDa BZ2 protein is loosely membrane-bound, but it was detectable only in tissues accumulating anthocyanin. Consequently, BZ2 accumulation appears to be limited by stringent post-transcriptional regulation.

  18. Genetic evidence for an origin of the Armenians from Bronze Age mixing of multiple populations.

    Science.gov (United States)

    Haber, Marc; Mezzavilla, Massimo; Xue, Yali; Comas, David; Gasparini, Paolo; Zalloua, Pierre; Tyler-Smith, Chris

    2016-06-01

    The Armenians are a culturally isolated population who historically inhabited a region in the Near East bounded by the Mediterranean and Black seas and the Caucasus, but remain under-represented in genetic studies and have a complex history including a major geographic displacement during World War I. Here, we analyse genome-wide variation in 173 Armenians and compare them with 78 other worldwide populations. We find that Armenians form a distinctive cluster linking the Near East, Europe, and the Caucasus. We show that Armenian diversity can be explained by several mixtures of Eurasian populations that occurred between ~3000 and ~2000 bce, a period characterized by major population migrations after the domestication of the horse, appearance of chariots, and the rise of advanced civilizations in the Near East. However, genetic signals of population mixture cease after ~1200 bce when Bronze Age civilizations in the Eastern Mediterranean world suddenly and violently collapsed. Armenians have since remained isolated and genetic structure within the population developed ~500 years ago when Armenia was divided between the Ottomans and the Safavid Empire in Iran. Finally, we show that Armenians have higher genetic affinity to Neolithic Europeans than other present-day Near Easterners, and that 29% of Armenian ancestry may originate from an ancestral population that is best represented by Neolithic Europeans.

  19. Microstructure, microhardness and dry friction behavior of cold-sprayed tin bronze coatings

    Science.gov (United States)

    Guo, Xueping; Zhang, Ga; Li, Wen-Ya; Dembinski, Lucas; Gao, Yang; Liao, Hanlin; Coddet, Christian

    2007-12-01

    In this paper, two types of tin bronze coatings (Cu-6 wt.% Sn and Cu-8 wt.% Sn) were prepared by cold spray process. The as-sprayed coatings were subjected to a vacuum heat treatment at 600 °C for 3 h. The coating microstructure, microhardness and tribological performance were characterized. The effects of the tin content and the vacuum heat treatment on the microstructure, microhardness and tribological behavior of the coatings were investigated. It is found that the as-sprayed CuSn6 (As6) and CuSn8 (As8) coatings exhibit practically an identical porosity. Meanwhile, As8 presents a higher microhardness than As6. In addition, the increase of the tin content in the powder feedstock leads to a lower wear rate. After a heat treatment, coating porosities are significantly reduced. However, the coating hardness is significantly decreased and the coating presents a much decreased wear resistance. For the as-sprayed coatings, such factors as ploughing and particle delamination could determine the sliding process. The heat treatment results in a distinct modification of the tribological behavior. For the annealed coatings, the adhesion, between the coating and the counterpart, could play a dominant role in the sliding process.

  20. Stratospheric Ozone destruction by the Bronze-Age Minoan eruption (Santorini Volcano, Greece)

    Science.gov (United States)

    Cadoux, Anita; Scaillet, Bruno; Bekki, Slimane; Oppenheimer, Clive; Druitt, Timothy H.

    2015-01-01

    The role of volcanogenic halogen-bearing (i.e. chlorine and bromine) compounds in stratospheric ozone chemistry and climate forcing is poorly constrained. While the 1991 eruption of Pinatubo resulted in stratospheric ozone loss, it was due to heterogeneous chemistry on volcanic sulfate aerosols involving chlorine of anthropogenic rather than volcanogenic origin, since co-erupted chlorine was scavenged within the plume. Therefore, it is not known what effect volcanism had on ozone in pre-industrial times, nor what will be its role on future atmospheres with reduced anthropogenic halogens present. By combining petrologic constraints on eruption volatile yields with a global atmospheric chemistry-transport model, we show here that the Bronze-Age ‘Minoan’ eruption of Santorini Volcano released far more halogens than sulfur and that, even if only 2% of these halogens reached the stratosphere, it would have resulted in strong global ozone depletion. The model predicts reductions in ozone columns of 20 to >90% at Northern high latitudes and an ozone recovery taking up to a decade. Our findings emphasise the significance of volcanic halogens for stratosphere chemistry and suggest that modelling of past and future volcanic impacts on Earth’s ozone, climate and ecosystems should systematically consider volcanic halogen emissions in addition to sulfur emissions. PMID:26206616

  1. A family of rare earth molybdenum bronzes: Oxides consisting of periodic arrays of interacting magnetic units

    Science.gov (United States)

    Schneemeyer, L. F.; Siegrist, T.; Besara, T.; Lundberg, M.; Sun, J.; Singh, D. J.

    2015-07-01

    The family of rare earth molybdenum bronzes, reduced ternary molybdates of composition LnMo16O44, was synthesized and a detailed structural study carried out. Bond valence sum (BVS) calculations clearly show that the molybdenum ions in tetrahedral coordination are hexavalent while the electron count in the primitive unit cell is odd. Yet, measurements show that the phases are semiconductors. The temperature dependence of the magnetic susceptibility of samples containing several different rare earth elements was measured. These measurements verified the presence of a 6.5 K magnetic phase transition not arising from the rare earth constituent, but likely associated with the unique isolated ReO3-type Mo8O36 structural subunits in this phase. To better understand the behavior of these materials, electronic structure calculations were performed within density functional theory. Results suggest a magnetic state in which these structural moieties have an internal ferromagnetic arrangement, with small ~1/8 μB moments on each Mo. We suggest that the Mo8O36 units behave like pseudoatoms with spin 1/2 derived from a single hole distributed over the eight Mo atoms that are strongly hybridized with the O atoms of the subunit. Interestingly, while the compound is antiferromagnetic, our calculations suggest that a field-stabilized ferromagnetic state, if achievable, will be a narrow band half-metal.

  2. Crystal structure determination of a new sodium vanadium bronze electrochemically formed

    Science.gov (United States)

    Safrany Renard, Marianne; Emery, Nicolas; Roginskii, Evgenii M.; Baddour-Hadjean, Rita; Pereira-Ramos, Jean-Pierre

    2017-10-01

    γ-Na0.97V2O5 is synthesized by electrochemical reduction at constant current of γ'-V2O5 in a 1 M NaClO4 propylene carbonate electrolyte. This sodium vanadium pentoxide bronze has not heretofore been prepared. The structure of this new sodium insertion compound was solved by Rietveld refinement of the X-ray diffraction data and Raman spectroscopy. It exhibits an orthorhombic layered structure type (Pnma space group) with Na ions located in the large octahedral sites of the interlayer space. The structural features of γ-Na0.97V2O5 at the long range and atomic scale are provided and compared to those of γ'-V2O5 and the lithiated analogue γ-LiV2O5. Reliable 'structure-Raman spectrum' correlations are proposed and Raman peaks characteristics of the different structural units are identified. Preliminary electrochemical experiments show a strong interest of γ-Na0.97V2O5 as rechargeable high voltage cathode for Na batteries (specific capacity of 80-125 mAh g-1 at c. a. 3.3 V vs Na+/Na).

  3. EDXRF and micro-EDXRF studies of Late Bronze Age metallurgical productions from Canedotes (Portugal)

    Science.gov (United States)

    Valerio, Pedro; Araújo, M. de Fátima; Canha, Alexandre

    2007-10-01

    Metallurgical production in Central Portugal during the Late Bronze Age was primarily based on copper-tin alloys, despite influences from the Atlantic area where copper-tin-lead alloys are common. Metallic artefacts from archaeological site of Canedotes (Central Portugal) were analysed by EDXRF to establish the type of alloys present. Polished spots in selected artefacts were also analysed by micro-EDXRF to determine the major and minor elemental composition of the original alloys. The collection constitutes 18 copper-tin artefacts and one unalloyed copper artefact with tin and arsenic as minor constituents. Artefacts that require a thermomechanical finishing process, such as tools and weapons, seem to have improved control over the tin content. The composition of two buttons, one cramp and one metallic droplet suggest that some of the copper sources were rich in arsenic. Finally, the low iron content of the artefacts seems to agree well with the smelting of copper ores in crucible furnaces, a smelting process used in certain areas of the Iberian Peninsula until pre-Roman times.

  4. EDXRF and micro-EDXRF studies of Late Bronze Age metallurgical productions from Canedotes (Portugal)

    Energy Technology Data Exchange (ETDEWEB)

    Valerio, Pedro [Instituto Technologico e Nuclear, Chemistry, Estrada Nacional 10, 2686-953 Sacavem, Lisbon (Portugal)], E-mail: pvalerio@itn.pt; Araujo, M. de Fatima [Instituto Technologico e Nuclear, Chemistry, Estrada Nacional 10, 2686-953 Sacavem, Lisbon (Portugal); Canha, Alexandre [Centro de Estudos Pre-historicos da Beira Alta, Largo Antonio Jose Pereira, 3501-997 Viseu (Portugal)

    2007-10-15

    Metallurgical production in Central Portugal during the Late Bronze Age was primarily based on copper-tin alloys, despite influences from the Atlantic area where copper-tin-lead alloys are common. Metallic artefacts from archaeological site of Canedotes (Central Portugal) were analysed by EDXRF to establish the type of alloys present. Polished spots in selected artefacts were also analysed by micro-EDXRF to determine the major and minor elemental composition of the original alloys. The collection constitutes 18 copper-tin artefacts and one unalloyed copper artefact with tin and arsenic as minor constituents. Artefacts that require a thermomechanical finishing process, such as tools and weapons, seem to have improved control over the tin content. The composition of two buttons, one cramp and one metallic droplet suggest that some of the copper sources were rich in arsenic. Finally, the low iron content of the artefacts seems to agree well with the smelting of copper ores in crucible furnaces, a smelting process used in certain areas of the Iberian Peninsula until pre-Roman times.

  5. A Male Aggregation Pheromone in the Bronze Bug, Thaumastocoris peregrinus (Thaumastocoridae

    Directory of Open Access Journals (Sweden)

    Andrés González

    2012-01-01

    Full Text Available Forest plantations in Uruguay have doubled in the past decade, with Eucalyptus spp. leading this growth. The bronze bug, Thaumastocoris peregrinus (Heteroptera: Thaumastocoridae, originally restricted to Australia, is an important emerging pest of Eucalyptus plantations in the Southern hemisphere. T. peregrinus feeds on mature Eucalyptus leaves, causing them to turn brown and often fall from the tree. Although population dynamics and behavioural patterns are not clearly understood, circumstantial observations suggest that males and nymphs aggregate. We used gas chromatography coupled to mass spectrometry to analyze volatile organic compounds emitted by virgin males and females, and characterized a male-specific compound, 3-methylbut-2-enyl butanoate, based on mass spectral data and chromatographic comparison with a synthetic standard. We also performed Y-olfactometer bioassays to test the attraction of virgin males and females toward live virgin males, male volatile extracts, and synthetic 3-methylbut-2-enyl butanoate. Males were attracted toward conspecific males, while virgin females showed no preference, suggesting that male volatiles are not involved in sexual communication. Further olfactometer tests showed that males were attracted to male volatile extracts and to synthetic 3-methylbut-2-enyl butanoate. The ecological significance of this compound and its potential use for the management of T. peregrinus in Eucalyptus forests will be further investigated.

  6. The ``Madonna di Loreto'' Bronze Age Sanctuary and its Stone Calendar

    Science.gov (United States)

    Tunzi, A.; Zupone, M. L.; Antonello, E.

    2009-08-01

    The ``Madonna di Loreto'' (Trinitapoli, Puglia) site is the largest Bronze Age sanctuary presently known in Italy. Inside its area, several hypogeal structures excavated in the calcareous rock and devoted to ritual use were found. The most impressive manifestation of the cult is however a set of more than 1000 circular holes, aligned in rows and covering the whole sacred area. The holes were excavated during many centuries, following a rigid plan and taking into account specific celestial points. The archaeoastronomical study of the rows revealed three main alignments: that with the highest frequency, i.e. with the highest number of holes, is along the meridian, thus referring to astronomical phenomena with a daily periodicity; that with an intermediate frequency to a phenomenon with annual periodicity (the azimuth of the sunrise on a peculiar day, near to the summer solstice), and that with the lowest frequency to the South major lunistice, a phenomenon with a long term (18.6 years) periodicity. This agreement has a very high statistical significance and it allows us to interpret the hole rows as elements of a complex calendric system with a ritual character.

  7. Fabricating Superior NiAl Bronze Components through Wire Arc Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Donghong Ding

    2016-08-01

    Full Text Available Cast nickel aluminum bronze (NAB alloy is widely used for large engineering components in marine applications due to its excellent mechanical properties and corrosion resistance. Casting porosity, as well as coarse microstructure, however, are accompanied by a decrease in mechanical properties of cast NAB components. Although heat treatment, friction stir processing, and fusion welding were implemented to eliminate porosity, improve mechanical properties, and refine the microstructure of as-cast metal, their applications are limited to either surface modification or component repair. Instead of traditional casting techniques, this study focuses on developing NAB components using recently expanded wire arc additive manufacturing (WAAM. Consumable welding wire is melted and deposited layer-by-layer on substrates producing near-net shaped NAB components. Additively-manufactured NAB components without post-processing are fully dense, and exhibit fine microstructure, as well as comparable mechanical properties, to as-cast NAB alloy. The effects of heat input from the welding process and post-weld-heat-treatment (PWHT are shown to give uniform NAB alloys with superior mechanical properties revealing potential marine applications of the WAAM technique in NAB production.

  8. Computed tomography of a medium size Roman bronze statue of Cupid

    Energy Technology Data Exchange (ETDEWEB)

    Bettuzzi, M.; Brancaccio, R. [University of Bologna, Department of Physics and Astronomy, Bologna (Italy); Casali, F.; Morigi, M.P. [University of Bologna, Department of Physics and Astronomy, Bologna (Italy); Centro Fermi, Rome (Italy); Carson, D.; Chiari, G. [Getty Conservation Institute, Los Angeles, CA (United States); Maish, J. [The J. Paul Getty Museum, Los Angeles, CA (United States)

    2015-01-14

    Diagnostics based on X-ray computed tomography (CT) are becoming increasingly important, not only in the medical field but in industry and cultural heritage. CT devices typical for medical applications, however, can seldom be used on art objects because both they are not easily transportable and they often present high X-ray absorption. It is therefore necessary to make use of portable instrumentation and/or to develop tomographic systems optimized to the characteristics of the objects under examination. This work describes the computed tomography of a first century A.D. Roman bronze statue of Cupid (96.AB.53) in the collection of the J. Paul Getty Museum, within the collaborative framework between the Getty Conservation Institute and the Department of Physics and Astronomy (DIFA) of the University of Bologna (Italy). The tomography performed at the Getty facilities employed a 450 kV X-ray tube and a detection system developed at DIFA. The study highlighted the casting and construction techniques used by Roman foundry workers and provided information on the status of conservation of the statue. A 3D virtual reconstruction allowed the user to define different cross-sections enabling the study of the internal features. (orig.)

  9. Atomic resolution imaging of precipitate transformation from cubic TaN to tetragonal CrTaN

    DEFF Research Database (Denmark)

    Danielsen, Hilmar Kjartansson; Hald, John; Somers, Marcel A. J.

    2012-01-01

    In 9–12% Cr creep-resistant steels Cr(V,Nb,Ta)N Z-phase is known to replace metastable (V,Nb,Ta)N MN precipitates at high temperatures. The precipitation process of Z-phase does not follow the classical nucleation theory, where dissolving MN particles provide constituents for Z-phase nucleation...... in the matrix. Using atomic resolution transmission electron microscopy, the current work demonstrates that metastable cubic TaN precipitates in a complex steel gradually transform compositionally and crystallographically into stable tetragonal CrTaN precipitates under the influence of Cr indiffusion from...... the steel matrix....

  10. Effects of oxygen nonstoichiometry on the high-temperature performance of an yttria-tetragonal zirconia polycrystal material

    Energy Technology Data Exchange (ETDEWEB)

    Swab, J.J.; Katz, R.N.; Starita, C.J. (Army Materials Technology Lab., Watertown, MA (USA))

    1988-05-01

    The hot isostatic pressing of an yttria-tetragonal zirconia polycrystal (Y-TZP) powder yields a body that is slightly reduced. Stepped-temperature stress-rupture tests revealed that a hot isostatically pressed Y-TZP has anomalous time-dependent failure behavior through the temperature range 800{degree} to 1,200{degree}C. However, this anomaly can effectively be eliminated, and the stress-rupture performance significantly improved, by oxidizing the pressed body at 1,000{degree}C before use.

  11. Tetragonal-to-orthorhombic structural phase transition at 90 K in the superconductor Fe(1.01)Se.

    Science.gov (United States)

    McQueen, T M; Williams, A J; Stephens, P W; Tao, J; Zhu, Y; Ksenofontov, V; Casper, F; Felser, C; Cava, R J

    2009-07-31

    In this Letter we show that superconducting Fe(1.01)Se undergoes a structural transition at 90 K from a tetragonal to an orthorhombic phase but that nonsuperconducting Fe(1.03)Se does not. High resolution electron microscopy at low temperatures further reveals an unexpected additional modulation of the crystal structure of the superconducting phase that involves displacements of the Fe atoms, and that the nonsuperconducting composition shows a different, complex nanometer-scale structural modulation. Finally, we show that magnetism is not the driving force for the phase transition in the superconducting phase.

  12. Tetragonal-to-Orthorhombic Structural Phase Transition at 90K in the Superconductor for Fe 1.01Se

    Energy Technology Data Exchange (ETDEWEB)

    McQueen, T.; Williams, A; Stephens, P; Tao, J; Zhu, Y; Ksenofontov, V; Casper, F; Felser, C; Cava, R

    2009-01-01

    In this Letter we show that superconducting Fe1.01Se undergoes a structural transition at 90 K from a tetragonal to an orthorhombic phase but that nonsuperconducting Fe1.03Se does not. High resolution electron microscopy at low temperatures further reveals an unexpected additional modulation of the crystal structure of the superconducting phase that involves displacements of the Fe atoms, and that the nonsuperconducting composition shows a different, complex nanometer-scale structural modulation. Finally, we show that magnetism is not the driving force for the phase transition in the superconducting phase.

  13. Tetragonal-to-Orthorhombic Structural Phase Transition at 90Kin the Superconductor Fe1:01Se

    Energy Technology Data Exchange (ETDEWEB)

    McQueen, T.M.; Tao, J.; Williams, A.J.; Stephens, P.W.; Zhu, Y.; Ksenofontov, V.; Casper, F.; 4 C.; Cava, R.J.

    2009-07-30

    In this Letter we show that superconducting Fe{sub 1.01}Se undergoes a structural transition at 90 K from a tetragonal to an orthorhombic phase but that nonsuperconducting Fe{sub 1.03}Se does not. High resolution electron microscopy at low temperatures further reveals an unexpected additional modulation of the crystal structure of the superconducting phase that involves displacements of the Fe atoms, and that the nonsuperconducting composition shows a different, complex nanometer-scale structural modulation. Finally, we show that magnetism is not the driving force for the phase transition in the superconducting phase.

  14. The role of orbital ordering in the tetragonal-to-cubic phase transition in CuCr 2O 4

    Science.gov (United States)

    Kennedy, Brendan J.; Zhou, Qingdi

    2008-09-01

    Copper(II) chromite (CuCr 2O 4) undergoes a first-order structural transition from a tetragonal distorted spinel structure in space group ( I4 1/ amd) to a cubic spinel structure in Fd3¯ m, near 600 °C. The transition has been followed using synchrotron X-ray powder diffraction between room temperature and 750 °C. The structure changes as a consequence of a transition from an orbitally ordered to orbital disordered state associated with a Jahn-Teller-type distortion of the CuO 4 tetrahedron. The orbital melting results in a small increase in cell volume.

  15. Release of copper from sintered tungsten-bronze shot under different pH conditions and its potential toxicity to aquatic organisms.

    Science.gov (United States)

    Thomas, Vernon G; Santore, Robert C; McGill, Ian

    2007-03-01

    Sintered tungsten-bronze is a new substitute for lead shot, and is about to be deposited in and around the wetlands of North America. This material contains copper in the alloyed form of bronze. This in vitro study was performed according to U.S. Fish and Wildlife Service criteria to determine the dissolution rate of copper from the shot, and to assess the toxic risk that it may present to aquatic organisms. The dissolution of copper from tungsten-bronze shot, pure copper shot, and glass beads was measured in a buffered, moderately hard, synthetic water of pH 5.5, 6.6, and 7.8 over a 28-day period. The dissolution of copper from both the control copper shot and the tungsten-bronze shot was affected significantly by the pH of the water and the duration of dissolution (all p valuescopper release from tungsten bronze shot was 30 to 50 times lower than that from the copper shot, depending on pH (pcopper released from tungsten-bronze shot after 28 days was 0.02 microg/L at pH 7.8, and 0.4 microg/L at pH 5.6, using a loading and exposure scenario specific in a U.S. Fish and Wildlife Service protocol. Ratio Quotient values derived from the highest EEC observed in this study (0.4 microg/L), and the copper toxic effect levels for all aquatic species listed in the U.S. Environmental Protection Agency ambient water quality criteria database, were all far less than the 0.1 criterion value. Given the conditions stipulated by the U.S. Fish and Wildlife Service and the U.S. Environmental Protection Agency, heavy loading from discharged tungsten-bronze shot would not pose a toxic risk to potable water, or to soil. Consequently, it would appear that no toxic risks to aquatic organisms will attend the use of tungsten-bronze shot of the approved composition. Given the likelihood that sintered tungsten-bronze of the same formula will be used for fishing weights, bullets, and wheel balance weights, it is expected that the use of this new material in these applications will not be

  16. Simboluri sociale în epoca bronzului. Sceptre de corn şi os / Social symbols in the Bronze Age. Antler and bone scepters

    Directory of Open Access Journals (Sweden)

    Vasile Diaconu

    2014-10-01

    Full Text Available The present study discusses the antler and bone scepters specific for the Romanian Bronze Age. This type of objects have been found since the Neolithic period, they are frequently encountered during the Bronze Age and rarely discovered in the first period of the Iron Age. The majority of the pieces are made of antler and only a couple of them are made of bone. Some of the pieces, beautifully decorated have a central perforation in order to fix it in a wooden handle. Concerning the archaeological context of the findings, the majority of the objects were discovered inside the settlements and only one piece is part of the inventory of a tomb. The antler and bone scepters have been discovered in different archaeological cultures since the Early Bronze Age, but the majority of the pieces are attributed to the Middle Bronze Age (the Monteoru, Wietenberg, Costişa, Otomani, Verbicioara cultures. For the Late Bronze Age we only know one item. The signification of such items is primarily related to the social symbolism, but they can also be interpreted as cult objects in the case of their utilization during religious rituals.

  17. Sol-gel preparation and photoluminescence properties of tetragonal ZrO2:Y3+, Eu3+ nanophosphors

    Science.gov (United States)

    Liao, Jinsheng; Zhou, Dan; Yang, Bin; Liu, Ruiqing; Zhang, Qian

    2012-12-01

    By controlling Eu3+ doping concentration, ZrO2:Y3+, Eu3+ (YSZ:Eu) nanophosphors with tetragonal structure have been prepared by sol-gel method. The properties of the resulting phosphors are characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), photoluminescence (PL) spectra and decay curve. The excitation spectra of YSZ:Eu phosphors are mainly attributed to O2- → Eu3+ charge-transfer (CT) band at about 254 nm and some sharp lines of Eu3+ f-f transitions in near-UV region with one strong peak at 395 nm. The emission spectra were used to probe the local environments of Eu3+ ion in ZrO2 crystal. Based on the high-resolution emission and excitation spectra at 10 K, it is identified that the lattice site of Eu3+ in tetragonal ZrO2 nanocrystals descending from D4h to approximate C2V as a result of the lattice distortion. Under the 395 nm excitation, intense red emission peaked at 607 nm corresponding to 5D0 → 7F2 transition of Eu3+ is observed for 6 at.% YSZ:Eu phosphors as the optimal doping concentration. The luminescence properties suggest that YSZ:Eu phosphor may be regarded as a potential red phosphor candidate for near-UV light emitting diodes (LEDs).

  18. Ionic and Optical Properties of Methylammonium Lead Iodide Perovskite across the Tetragonal-Cubic Structural Phase Transition.

    Science.gov (United States)

    Hoque, Md Nadim Ferdous; Islam, Nazifah; Li, Zhen; Ren, Guofeng; Zhu, Kai; Fan, Zhaoyang

    2016-09-22

    Practical hybrid perovskite solar cells (PSCs) must endure temperatures above the tetragonal-cubic structural phase transition of methylammonium lead iodide (MAPbI3 ). However, the ionic and optical properties of MAPbI3 in such a temperature range, and particularly, dramatic changes in these properties resulting from a structural phase transition, are not well studied. Herein, we report a striking contrast at approximately 45 °C in the ionic/electrical properties of MAPbI3 owing to a change of the ion activation energy from 0.7 to 0.5 eV, whereas the optical properties exhibit no particular transition except for the steady increase of the bandgap with temperature. These observations can be explained by the "continuous" nature of perovskite phase transition. We speculate that the critical temperature at which the ionic/electrical properties change, although related to crystal symmetry variation, is not necessarily the same temperature as when tetragonal-cubic structural phase transition occurs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Ionic and Optical Properties of Methylammonium Lead Iodide Perovskite across the Tetragonal-Cubic Structural Phase Transition

    Energy Technology Data Exchange (ETDEWEB)

    Hoque, Md Nadim Ferdous [Department of Electrical and Computer Engineering and Nano Tech Center, Texas Tech University, Lubbock Texas 79409 USA; Islam, Nazifah [Department of Electrical and Computer Engineering and Nano Tech Center, Texas Tech University, Lubbock Texas 79409 USA; Li, Zhen [Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden Colorado 80401 USA; Ren, Guofeng [Department of Electrical and Computer Engineering and Nano Tech Center, Texas Tech University, Lubbock Texas 79409 USA; Zhu, Kai [Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden Colorado 80401 USA; Fan, Zhaoyang [Department of Electrical and Computer Engineering and Nano Tech Center, Texas Tech University, Lubbock Texas 79409 USA

    2016-09-01

    Practical hybrid perovskite solar cells (PSCs) must endure temperatures above the tetragonal-cubic structural phase transition of methylammonium lead iodide (MAPbI3). However, the ionic and optical properties of MAPbI3 in such a temperature range, and particularly, dramatic changes in these properties resulting from a structural phase transition, are not well studied. Herein, we report a striking contrast at approximately 45 degrees C in the ionic/electrical properties of MAPbl3 owing to a change of the ion activation energy from 0.7 to 0.5 eV, whereas the optical properties exhibit no particular transition except for the steady increase of the bandgap with temperature. These observations can be explained by the 'continuous' nature of perovskite phase transition. We speculate that the critical temperature at which the ionic/electrical properties change, although related to crystal symmetry variation, is not necessarily the same temperature as when tetragonal-cubic structural phase transition occurs.

  20. Facile Route to the Controlled Synthesis of Tetragonal and Orthorhombic SnO2 Films by Mist Chemical Vapor Deposition.

    Science.gov (United States)

    Bae, Jae-Yoon; Park, Jozeph; Kim, Hyun You; Kim, Hyun-Suk; Park, Jin-Seong

    2015-06-10

    Two types of tin dioxide (SnO2) films were grown by mist chemical vapor deposition (Mist-CVD), and their electrical properties were studied. A tetragonal phase is obtained when methanol is used as the solvent, while an orthorhombic structure is formed with acetone. The two phases of SnO2 exhibit different electrical properties. Tetragonal SnO2 behaves as a semiconductor, and thin-film transistors (TFTs) incorporating this material as the active layer exhibit n-type characteristics with typical field-effect mobility (μ(FE)) values of approximately 3-4 cm(2)/(V s). On the other hand, orthorhombic SnO2 is found to behave as a metal-like transparent conductive oxide. Density functional theory calculations reveal that orthorhombic SnO2 is more stable under oxygen-rich conditions, which correlates well with the experimentally observed solvent effects. The present study paves the way for the controlled synthesis of functional materials by atmospheric pressure growth techniques.

  1. Bronze Jewellery from the Early Iron Age urn-field in Mała Kępa. An approach to casting technology

    Directory of Open Access Journals (Sweden)

    Garbacz-Klempka A.

    2017-09-01

    Full Text Available This study characterizes the bronze jewellery recovered from the Lusatian culture urn-field in Mała Kępa (Chełmno land, Poland. Among many common ornaments (e.g. necklaces, rings, pins the ones giving evidence of a steppe-styled inspiration (nail earrings were also identified. With the dendritic microstructures revealed, the nail earrings prove the implementing of a lost-wax casting method, whereas some of the castings were further subjected to metalworking. The elemental composition indicates the application of two main types of bronze alloys: Cu-Sn and Cu-Sn-Pb. It has been established that the Lusatian metalworkers were familiar with re-melting the scrap bronze and made themselves capable of roasting the sulphide-rich ores.

  2. Agricultural production and stability of settlement systems in Upper Mesopotamia during the Early Bronze Age (third millennium BCE)

    Science.gov (United States)

    Kalayci, Tuna

    This study investigates the relationship between rainfall variation and rain-fed agricultural production in Upper Mesopotamia with a specific focus on Early Bronze Age urban settlements. In return, the variation in production is used to explore stability of urban settlement systems. The organization of the flow of agricultural goods is the key to sustaining the total settlement system. The vulnerability of a settlement system increases due to the increased demand for more output from agricultural lands. This demand is the key for the success of urbanization project. However, without estimating how many foodstuffs were available at the end of a production cycle, further discussions on the forces that shaped and sustained urban settlement systems will be lacking. While large scale fluctuations in the flow of agricultural products between settlements are not the only determinants of hierarchical structures, the total available agricultural yield for each urban settlement in a hierarchy must have influenced settlement relations. As for the methodology, first, Early Bronze Age precipitation levels are estimated by using modern day associations between the eastern Mediterranean coastal areas and the inner regions of Upper Mesopotamia. Next, these levels are integrated into a remote-sensing based biological growth model. Also, a CORONA satellite imagery based archaeological survey is conducted in order to map the Early Bronze Age settlement system in its entirety as well as the ancient markers of agricultural intensification. Finally, ancient agricultural production landscapes are modeled in a GIS. The study takes a critical position towards the traditionally held assumption that large urban settlements (cities) in Upper Mesopotamia were in a state of constant demand for food. The results from this study also suggest that when variations in ancient precipitation levels are translated into the variations in production levels, the impact of climatic aridification on ancient

  3. Chronological aspects of the funerary deposit and Bronze Age fortified settlement of Chao Samartín

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    Villa Valdés, Ángel

    2003-12-01

    Full Text Available The Chao Samartín hillfort, in western Asturias, was initially fortified at the end of the Bronze Age. A large building enclosed within several defensive lines was present at the settlement around the 8th century B.C., its excavation yielding important bronze artefacts. A small stone urn containing a human female cranium has been recently uncovered by the main gate of this fortress. The aim of this contribution is to present a set of new radiocarbon dates that allow us to ascertain the placement of this burial within the chrono-archaeological context of the Final Bronze Age settlement.

    El castro de Chao Samartín, en el occidente de Asturias, remonta su condición de asentamiento fortificado a finales de la Edad del Bronce. Durante el siglo VIII a.C. defensas monumentales delimitaban un recinto en el que se alzaba, en posición principal, una cabaña de grandes dimensiones de la que procede un interesante repertorio de materiales metálicos fabricados en bronce. Junto a la puerta de acceso al recinto, al pie de la fortificación, se instaló una pequeña cista que contenía el cráneo de una mujer joven. Este artículo presenta las nuevas dataciones que permiten establecer la antigüedad del depósito y su contextualización crono-arqueológica con el establecimiento del Bronce Final.

  4. Roman Bronze Vessels From the Late Sarmatian Burial of the Lebedevka Burial-Ground in Western Kazakhstan

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    Treister Mikhail Yuryevich

    2015-12-01

    Full Text Available This paper is devoted to studying cultural monuments – bronze vessels, a jug and a basin from the barrow no. 1/1967 of the Lebedevka Late Sarmatian burial mound (Western Kazakhstan, dating back to the middle of the 3rd century AD at the latest. These items do not find exact parallels among the bronze vessels of provincial Rome. Although the shape of the jug handle with a curved leaf turned upright between two horizontally arranged swan heads has parallels on the so-called “composite jug with handles” (“gegliederten Henkelkrügen”, the cylindrical form of the jug’s neck peculiar of the glass jugs of allegedly Syrian manufacture of the second half of the 3rd-4th centuries AD is very unusual. Even more unusual is a basin with horizontally bent rim and elaborate handles with pearls on a high narrow stand-ring. The XRF analyses of the Lebedevka jug’s metal revealed that its body and handle were made of a copper-based alloy with very high admixtures of zinc (24-27 % and inconsiderable additions of lead (up to 3 %. A similar alloy was used for manufacturing a vessel in the form of a crouching young negro from Niederbieber. Most objects of provincial Roman import reached Western Kazakhstan via the Bosporan kingdom along the Northern branch of the Silk Road. The above discussed bronze vessels from Lebedevka let suggest, that the nomads could receive some import articles that were brought along the caravan routes leading from Egypt and Syria to the East.

  5. Technical and Technological Analysis of the Ceramics of the Late Bronze Archaeological Monument Ozerki-1 in the Bashkir Urals

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    Mukhametdinov Vadim Ildarovich

    2015-12-01

    Full Text Available The relevance of studying small settlements in recent years is associated with the lack of information about the monuments of this type. The data on small settlements can help to find answers to a number of topical issues, such as settlement system, interaction with large settlements. The location of small settlements near water bodies attests to the fact of using them primarily as seasonal shelters. These places also served as pastures for the flock. The article contains the results of technical and technological analysis of ceramics obtained during the study of archaeological site of the late bronze age Ozerki-1. The monument is located on the territory of the Beregovsky archaeological district the Meleuzovsky region of the Republic of Bashkortostan. The analysis of ceramics was carried out within the historical and cultural approach, according to the technique developed by A.A. Bobrinsky. The study let reveal a large number of recipes of moulding materials. This data obtained during the analysis of ceramics in a comparatively small area of excavation, may be associated with the active process of transformations of adaptive pottery traditions that were taking place in the course of cross-cultural contacts. As a result of excavations, the author obtained the new data on the economic activity of the population of the Western slopes of the southern Urals in the Late Bronze Age. The findings let discover the traces of metallurgy, find the bones of domestic animals, reveal the location of small settlements around large settlements. The fact of business chain existence, including farming, industry of stone and steel processing testifies to the possible autonomy of the studied areas. The data can be used in comparative works that reflect the course of historical processes of the Late Bronze Age on the territory of the forest-steppe Urals.

  6. Monumental megalithic burial and rock art tell a new story about the Levant Intermediate Bronze “Dark Ages”

    Science.gov (United States)

    Barash, Alon; Eisenberg-Degen, Davida; Grosman, Leore; Oron, Maya; Berger, Uri

    2017-01-01

    The Intermediate Bronze Age (IB) in the Southern Levant (ca. 2350–2000 BCE) is known as the “Dark Ages,” following the collapse of Early Bronze urban society and predating the establishment of the Middle Bronze cities. The absence of significant settlements and monumental building has led to the reconstruction of IB social organization as that of nomadic, tribal society inhabiting rural villages with no central governmental system. Excavation in the Shamir Dolmen Field (comprising over 400 dolmens) on the western foothills of the Golan Heights was carried out following the discovery of rock art engravings on the ceiling of the central chamber inside one of the largest dolmens ever recorded in the Levant. Excavation of this multi-chambered dolmen, covered by a basalt capstone weighing some 50 tons, revealed a secondary multi-burial (of both adults and children) rarely described in a dolmen context in the Golan. Engraved into the rock ceiling above the multi-burial is a panel of 14 forms composed of a vertical line and downturned arc motif. 3D-scanning by structured-light technology was used to sharpen the forms and revealed the technique employed to create them. Building of the Shamir dolmens required a tremendous amount of labor, architectural mastery, and complex socio-economic organization well beyond the capacity of small, rural nomadic groups. The monumental megalithic burial of the Shamir dolmens indicates a hierarchical, complex, non-urban governmental system. This new evidence supports a growing body of recent criticism stemming from new discoveries and approaches that calls for rethinking our views of the Levantine IB “Dark Ages.” PMID:28253312

  7. Monumental megalithic burial and rock art tell a new story about the Levant Intermediate Bronze "Dark Ages".

    Science.gov (United States)

    Sharon, Gonen; Barash, Alon; Eisenberg-Degen, Davida; Grosman, Leore; Oron, Maya; Berger, Uri

    2017-01-01

    The Intermediate Bronze Age (IB) in the Southern Levant (ca. 2350-2000 BCE) is known as the "Dark Ages," following the collapse of Early Bronze urban society and predating the establishment of the Middle Bronze cities. The absence of significant settlements and monumental building has led to the reconstruction of IB social organization as that of nomadic, tribal society inhabiting rural villages with no central governmental system. Excavation in the Shamir Dolmen Field (comprising over 400 dolmens) on the western foothills of the Golan Heights was carried out following the discovery of rock art engravings on the ceiling of the central chamber inside one of the largest dolmens ever recorded in the Levant. Excavation of this multi-chambered dolmen, covered by a basalt capstone weighing some 50 tons, revealed a secondary multi-burial (of both adults and children) rarely described in a dolmen context in the Golan. Engraved into the rock ceiling above the multi-burial is a panel of 14 forms composed of a vertical line and downturned arc motif. 3D-scanning by structured-light technology was used to sharpen the forms and revealed the technique employed to create them. Building of the Shamir dolmens required a tremendous amount of labor, architectural mastery, and complex socio-economic organization well beyond the capacity of small, rural nomadic groups. The monumental megalithic burial of the Shamir dolmens indicates a hierarchical, complex, non-urban governmental system. This new evidence supports a growing body of recent criticism stemming from new discoveries and approaches that calls for rethinking our views of the Levantine IB "Dark Ages."

  8. Monumental megalithic burial and rock art tell a new story about the Levant Intermediate Bronze "Dark Ages".

    Directory of Open Access Journals (Sweden)

    Gonen Sharon

    Full Text Available The Intermediate Bronze Age (IB in the Southern Levant (ca. 2350-2000 BCE is known as the "Dark Ages," following the collapse of Early Bronze urban society and predating the establishment of the Middle Bronze cities. The absence of significant settlements and monumental building has led to the reconstruction of IB social organization as that of nomadic, tribal society inhabiting rural villages with no central governmental system. Excavation in the Shamir Dolmen Field (comprising over 400 dolmens on the western foothills of the Golan Heights was carried out following the discovery of rock art engravings on the ceiling of the central chamber inside one of the largest dolmens ever recorded in the Levant. Excavation of this multi-chambered dolmen, covered by a basalt capstone weighing some 50 tons, revealed a secondary multi-burial (of both adults and children rarely described in a dolmen context in the Golan. Engraved into the rock ceiling above the multi-burial is a panel of 14 forms composed of a vertical line and downturned arc motif. 3D-scanning by structured-light technology was used to sharpen the forms and revealed the technique employed to create them. Building of the Shamir dolmens required a tremendous amount of labor, architectural mastery, and complex socio-economic organization well beyond the capacity of small, rural nomadic groups. The monumental megalithic burial of the Shamir dolmens indicates a hierarchical, complex, non-urban governmental system. This new evidence supports a growing body of recent criticism stemming from new discoveries and approaches that calls for rethinking our views of the Levantine IB "Dark Ages."

  9. Effect of an External Electric Field on the Kinetics of Dislocation-Free Growth of Tetragonal Hen Egg White Lysozyme Crystals

    Directory of Open Access Journals (Sweden)

    Haruhiko Koizumi

    2017-06-01

    Full Text Available Dislocation-free tetragonal hen egg white (HEW lysozyme crystals were grown from a seed crystal in a cell. The rates of tetragonal HEW lysozyme crystal growth normal to the (110 and (101 faces with and without a 1-MHz external electric field were measured. A decrease in the typical growth rates of the crystal measured under an applied field at 1 MHz was observed, although the overall driving force increased. Assuming that the birth and spread mechanism of two-dimensional nucleation occurs, an increase in the effective surface energy of the step ends was realized in the presence of the electric field, which led to an improvement in the crystal quality of the tetragonal HEW lysozyme crystals. This article also discusses the increase in the effective surface energy of the step ends with respect to the change in the entropy of the solid.

  10. Characterizing a Middle Bronze palatial wine cellar from Tel Kabri, Israel.

    Science.gov (United States)

    Koh, Andrew J; Yasur-Landau, Assaf; Cline, Eric H

    2014-01-01

    Scholars have for generations recognized the importance of wine production, distribution, and consumption in relation to second millennium BC palatial complexes in the Mediterranean and Near East. However, direct archaeological evidence has rarely been offered, despite the prominence of ancient viticulture in administrative clay tablets, visual media, and various forms of documentation. Tartaric and syringic acids, along with evidence for resination, have been identified in ancient ceramics, but until now the archaeological contexts behind these sporadic discoveries had been uneven and vague, precluding definitive conclusions about the nature of ancient viticulture. The situation has now changed. During the 2013 excavation season of the Kabri Archaeological Project, a rare opportunity materialized when forty large storage vessels were found in situ in an enclosed room located to the west of the central courtyard within the Middle Bronze Age Canaanite palace. A comprehensive program of organic residue analysis has now revealed that all of the relatively uniform jars contain evidence for wine. Furthermore, the enclosed context inherent to a singular intact wine cellar presented an unprecedented opportunity for a scientifically intensive study, allowing for the detection of subtle differences in the ingredients or additives within similar wine jars of apparently the same vintage. Additives seem to have included honey, storax resin, terebinth resin, cedar oil, cyperus, juniper, and perhaps even mint, myrtle, or cinnamon, all or most of which are attested in the 18th century BC Mari texts from Mesopotamia and the 15th century BC Ebers Papyrus from Egypt. These additives suggest a sophisticated understanding of the botanical landscape and the pharmacopeic skills necessary to produce a complex beverage that balanced preservation, palatability, and psychoactivity. This new study has resulted in insights unachievable in the past, which contribute to a greater understanding

  11. Characterizing a Middle Bronze palatial wine cellar from Tel Kabri, Israel.

    Directory of Open Access Journals (Sweden)

    Andrew J Koh

    Full Text Available Scholars have for generations recognized the importance of wine production, distribution, and consumption in relation to second millennium BC palatial complexes in the Mediterranean and Near East. However, direct archaeological evidence has rarely been offered, despite the prominence of ancient viticulture in administrative clay tablets, visual media, and various forms of documentation. Tartaric and syringic acids, along with evidence for resination, have been identified in ancient ceramics, but until now the archaeological contexts behind these sporadic discoveries had been uneven and vague, precluding definitive conclusions about the nature of ancient viticulture. The situation has now changed. During the 2013 excavation season of the Kabri Archaeological Project, a rare opportunity materialized when forty large storage vessels were found in situ in an enclosed room located to the west of the central courtyard within the Middle Bronze Age Canaanite palace. A comprehensive program of organic residue analysis has now revealed that all of the relatively uniform jars contain evidence for wine. Furthermore, the enclosed context inherent to a singular intact wine cellar presented an unprecedented opportunity for a scientifically intensive study, allowing for the detection of subtle differences in the ingredients or additives within similar wine jars of apparently the same vintage. Additives seem to have included honey, storax resin, terebinth resin, cedar oil, cyperus, juniper, and perhaps even mint, myrtle, or cinnamon, all or most of which are attested in the 18th century BC Mari texts from Mesopotamia and the 15th century BC Ebers Papyrus from Egypt. These additives suggest a sophisticated understanding of the botanical landscape and the pharmacopeic skills necessary to produce a complex beverage that balanced preservation, palatability, and psychoactivity. This new study has resulted in insights unachievable in the past, which contribute to a

  12. Weaning practices among pastoralists: New evidence of infant feeding patterns from Bronze Age Eurasia.

    Science.gov (United States)

    Ventresca Miller, Alicia; Hanks, Bryan K; Judd, Margaret; Epimakhov, Andrey; Razhev, Dmitry

    2017-03-01

    This paper investigates infant feeding practices through stable carbon (δ(13) C) and nitrogen (δ(15) N) isotopic analyses of human bone collagen from Kamennyi Ambar 5, a Middle Bronze Age cemetery located in central Eurasia. The results presented are unique for the time period and region, as few cemeteries have been excavated to reveal a demographic cross-section of the population. Studies of weaning among pastoral societies are infrequent and this research adds to our knowledge of the timing, potential supplementary foods, and cessation of breastfeeding practices. Samples were collected from 41 subadults (nursing) that began at 6 months of age, occurred over several years of early childhood, and was completed by 4 years of age. Our results indicate that weaning was a multi-stage process that was unique among late prehistoric pastoralist groups in Eurasia that were dependent on milk products as a supplementary food. Our discussion centers on supporting this hypothesis with modern information on central and east Eurasian herding societies including the age at which complementary foods are introduced, the types of complementary foods, and the timing of the cessation of breastfeeding. Integral to this work is the nature of pastoral economies and their dependence on animal products, the impact of complementary foods on nutrition and health, and how milk processing may have affected nutrition content and digestibility of foods. This research on Eurasian pastoralists provides insights into the complexities of weaning among prehistoric pastoral societies as well as the potential for different complementary foods to be incorporated into infant diets in the past. © 2016 Wiley Periodicals, Inc.

  13. Genetic History of Xinjiang's Uyghurs Suggests Bronze Age Multiple-Way Contacts in Eurasia.

    Science.gov (United States)

    Feng, Qidi; Lu, Yan; Ni, Xumin; Yuan, Kai; Yang, Yajun; Yang, Xiong; Liu, Chang; Lou, Haiyi; Ning, Zhilin; Wang, Yuchen; Lu, Dongsheng; Zhang, Chao; Zhou, Ying; Shi, Meng; Tian, Lei; Wang, Xiaoji; Zhang, Xi; Li, Jing; Khan, Asifullah; Guan, Yaqun; Tang, Kun; Wang, Sijia; Xu, Shuhua

    2017-10-01

    The Uyghur people residing in Xinjiang, a territory located in the far west of China and crossed by the Silk Road, are a key ethnic group for understanding the history of human dispersion in Eurasia. Here we assessed the genetic structure and ancestry of 951 Xinjiang's Uyghurs (XJU) representing 14 geographical subpopulations. We observed a southwest and northeast differentiation within XJU, which was likely shaped jointly by the Tianshan Mountains, which traverses from east to west as a natural barrier, and gene flow from both east and west directions. In XJU, we identified four major ancestral components that were potentially derived from two earlier admixed groups: one from the West, harboring European (25-37%) and South Asian ancestries (12-20%), and the other from the East, with Siberian (15-17%) and East Asian (29-47%) ancestries. By using a newly developed method, MultiWaver, the complex admixture history of XJU was modeled as a two-wave admixture. An ancient wave was dated back to ∼3,750 years ago (ya), which is much earlier than that estimated by previous studies, but fits within the range of dating of mummies that exhibited European features that were discovered in the Tarim basin, which is situated in southern Xinjiang (4,000-2,000 ya); a more recent wave occurred around 750 ya, which is in agreement with the estimate from a recent study using other methods. We unveiled a more complex scenario of ancestral origins and admixture history in XJU than previously reported, which further suggests Bronze Age massive migrations in Eurasia and East-West contacts across the Silk Road. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Ancient road transport devices: Developments from the Bronze Age to the Roman Empire

    Science.gov (United States)

    Rossi, Cesare; Chondros, Thomas G.; Milidonis, Kypros F.; Savino, Sergio; Russo, Flavio

    2016-03-01

    The development of transportation systems has significantly enhanced the welfare and modernization of society. Wooden vehicles pulled by animals have been used for land transportation since the early Bronze Age. Whole-body gharries with rigid wheels pulled by oxen appeared in Crete by 2000 BC or earlier. Horses originating from the East were depicted in early Cretan seal-rings of the same period. The two-wheeled horsedrawn chariot was one of the most important inventions in history. This vehicle provided humanity its first concept of personal transport and was the key technology of war for 2000 years. Chariots of Mycenaean and Archaic Greece with light and flexible four-spoked wheels acting as spring suspensions were depicted in vase paintings. The development of this vehicle incorporated the seeds of a primitive design activity and was important for engineering. The Trojan horse since 1194 BC and the helepolis since 700 BC were the first known machines on a wheeled base transported by horses or self-powered. Ancient engineers invented bearings lubricated with fat, and Romans introduced the ancestors of ball bearings for their wagons and carts. The historic evolution of wheeled transportation systems, along with early traction, suspension, and braking systems, is presented in this paper. Analytical and numerical methods are incorporated to analyze the most conceivable loading situations of typically reconstructed wheeled transportation systems in ancient times. Traction requirements both for horse-driven machines and the power for internal motors are also analyzed. This study can serve as a basis for further development of detailed reconstruction of transportation systems in antiquity.

  15. Historical literacy and contradictory evidence in a Finnish high school setting: The Bronze Soldier of Tallinn

    Directory of Open Access Journals (Sweden)

    Anna Veijola

    2016-03-01

    Full Text Available This article revolves around three key issues. Firstly, Finnish national core curriculum fixes the focus of history teaching to students' critical and historical thinking skills and the traditional approach to history teaching as memorizing of facts and chains of events has been changing over the last 30 years. However, the Finnish core curriculum leaves a lot of maneuvering scope for schools and individual teachers and it would seem that teachers still emphasize content over skills with too little focus on historical thinking skills. Secondly, Finland has so far been lacking in research of students' historical thinking skills, even if it has been adopted as an important part of the curriculum. What existing research there is shows that only few students are able to evaluate the information available and make sense of contradictory interpretations of past events. Thirdly, this article reports an experiment that aimed at offering students more opportunities to develop their historical thinking skills and at the same time evaluated their ability for historical thinking. The case chosen was confrontation in Estonia between ethnic Russian and Estonian population around historical interpretations of the so-called Bronze Soldier that led to unrests and violence in Tallinn in 2007. Our research points out that Finnish students have a lot of weaknesses in their text skills. Furthermore, there is a need for research that would examine what kind of interventions change how students learn and how their ability for historical thinking can be improved. It would be equally important to evaluate teachers’ thinking, how they think about history and the way they implement national curriculum.

  16. Bronze flagon from Pontes with an inscription from the 29th Psalm of David

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    Popović Ivana

    2015-01-01

    Full Text Available During the campaign which took place in 1983 at the site of Pontes - Trajan’s Bridge near Kostol, in the layer between a house from the second half of the 9th century and a house from the 11th century, a treasury consisting of medieval iron tools placed around, or inserted into, a bronze flagon was discovered in a shallow pit. The whole find was named Treasury B. At first, the flagon itself was dated into the period between the 6th and the 8th centuries, however, we have recently dated it into the 6th-7th century. The inscription on the neck of the vessel is a paraphrase of the 3rd verse from the 29th Psalm of David. This is proof that the flagon was a liturgical vessel. In this text we are trying to show that this flagon was analogous to the specimen from the treasury from Vrap in Albania, whose deposition during the third part of the 7th century is connected with the activity of Bulgarian Khan Kuber. The Byzantine vessel was a part of treasure plundered from the Avars, and the production of this flagon, just as of that one from Pontes, can be dated into the period between the 6th century and the first half or the middle of the 7th century. [Projekat Ministarstva nauke Republike Srbije, br. 177007: Romanisation, urbanisation and transformation of urban centres of civil, military and residential character in Roman provinces in the territory of Serbia

  17. Fish remnants from the excavations of the Bronze Age barrow near Maryanskoe village (Dnepropetrovsk region, Ukraine

    Directory of Open Access Journals (Sweden)

    O. M. Kovalchuk

    2014-10-01

    Full Text Available The Bronze Age mound (2.5–2.3 kya BC is located near the Maryanskoe village (Apostolovskyi district, Dnepropetrovsk region and was excavated in 1953. The results of determination of the fish remnants, which were found during the excavation, are presented in the paper. Eleven species belonging to 9 genera, 5 families and 5 orders (Acipenseriformes, Cypriniformes, Siluriformes, Esociformes, Perciformes were identified: russian sturgeon Acipenser gueldenstaedtii Brandt et Ratzeburg, 1833, stellate sturgeon A. stellatus Pallas, 1771, common ide Idus idus (Linnaeus, 1758, common roach Rutilus rutilus (Linnaeus, 1758, pontic roach R. frisii (Nordmann, 1840, common bream Abramis brama (Linnaeus, 1758, common carp Cyprinus carpio Linnaeus, 1758, tench Tinca tinca (Linnaeus, 1758, european catfish Silurus glanis Linnaeus, 1758, northern pike Esox lucius (Linnaeus, 1758, and zander Sander lucioperca (Linnaeus, 1758. Most of them are quite common in the Dnieper river basin. It was found that carp fishes predominate in the number of species. Most of the bone remnants in the collection belong to zander, catfish and pike, while common roach, pontic roach and common bream are identified by the few bones. This may indicate a different role of these species in the diet of the local population. The ratio of skeletal elements in the collection is the evidence of the fish cutting on the site. Body length and weight was reconstructed for 64 fish specimens. It was found that they were mature and small-sized, except for catfish, pike and perch. Taking into account the characteristics of the funeral rituals of the Yamna culture population, fish bones from the mound near Maryanskoe can be remnants of the parting meal.

  18. Horse-mounted invaders from the Russo-Kazakh steppe or agricultural colonists from western Central Asia? A craniometric investigation of the Bronze Age settlement of Xinjiang.

    Science.gov (United States)

    Hemphill, Brian E; Mallory, J P

    2004-07-01

    Numerous Bronze Age cemeteries in the oases surrounding the Täklamakan Desert of the Tarim Basin in the Xinjiang Uyghur Autonomous Region, western China, have yielded both mummified and skeletal human remains. A dearth of local antecedents, coupled with woolen textiles and the apparent Western physical appearance of the population, raised questions as to where these people came from. Two hypotheses have been offered by archaeologists to account for the origins of Bronze Age populations of the Tarim Basin. These are the "steppe hypothesis" and the "Bactrian oasis hypothesis." Eight craniometric variables from 25 Aeneolithic and Bronze Age samples, comprising 1,353 adults from the Tarim Basin, the Russo-Kazakh steppe, southern China, Central Asia, Iran, and the Indus Valley, are compared to test which, if either, of these hypotheses are supported by the pattern of phenetic affinities possessed by Bronze Age inhabitants of the Tarim Basin. Craniometric differences between samples are compared with Mahalanobis generalized distance (d2), and patterns of phenetic affinity are assessed with two types of cluster analysis (the weighted pair average linkage method and the neighbor-joining method), multidimensional scaling, and principal coordinates analysis. Results obtained by this analysis provide little support for either the steppe hypothesis or the Bactrian oasis hypothesis. Rather, the pattern of phenetic affinities manifested by Bronze Age inhabitants of the Tarim Basin suggests the presence of a population of unknown origin within the Tarim Basin during the early Bronze Age. After 1200 B.C., this population experienced significant gene flow from highland populations of the Pamirs and Ferghana Valley. These highland populations may include those who later became known as the Saka and who may have served as "middlemen" facilitating contacts between East (Tarim Basin, China) and West (Bactria, Uzbekistan) along what later became known as the Great Silk Road. Copyright

  19. EXPERIMENTAL MONTAGE USED TO STUDY THE VIBRATION OF THE DRILL TOOL IN THE PROCESS OF MANUFACTURING THE BRONZE MATERIALS

    Directory of Open Access Journals (Sweden)

    Cosmin-Mihai MIRIŢOIU

    2013-05-01

    Full Text Available In this paper we present the experimental setup used to study the vibration of the drill tool, during the drilling of the bronze products. In this paper the vibrations are analyzed during the drilling on the universal lathe machines. This time, the tool is fixed in the movable boring head and will make a translation movement with constant feeding, and the workpiece spins around its axis of symmetry and it is fixed in the spindle head stock of the universal lathe machine

  20. CONTRIBUTIONS TO THE STUDY OF THE VIBRATIONS FREQUENCY OF THE DRILL TOOL IN THE PROCESS OF MANUFACTURING THE BRONZE MATERIALS

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    Cosmin-Mihai MIRIŢOIU

    2013-05-01

    Full Text Available In this paper we present the experimental testings used to study the vibration of the drill tool, during the drilling of the bronze products. We have used the experimental setup presented in Miriţoiu (2013[1]. In this paper the vibrations are analyzed during the drilling on the universal lathe machines. The main purpose of to find a correlation between the cutting speed and the frequency of the vibration by using the experimental results and the regression analysis

  1. Emission of organic compounds from mould and core binders used for casting iron, aluminium and bronze in sand moulds

    DEFF Research Database (Denmark)

    Tiedje, Niels Skat; Crepaz, Rudolf; Eggert, Torben

    2010-01-01

    of binders was monitored when cast iron, bronze and aluminium was poured in the moulds. Binder degradation was measured by collecting off gasses in a specially designed ventilation hood at a constant flow rate. Samples were taken from the ventilation system and analysed for hydrocarbons and CO content...... compositions were tested. A test method that provides uniform test conditions is described. The method can be used as general test method to analyse off gasses from binders. Moulds containing a standard size casting were produced and the amount and type of organic compounds resulting from thermal degradation...

  2. Non-utilitarian context of the burnt flint artifacts from the Bronze Age settlements in the Seversky Donets River region

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    Alexandr Kolesnik

    2017-12-01

    Full Text Available This brief overview discusses the burnt flint found at the Bronze Age settlements located in the middle flow of the Seversky Donets River region. The objects came from the settlements’ layers associated with various archaeological cultures and periods: the Late Catacomb, Babino, different stages of the Timber Grave, post-Timber Grave, and Bondarikhinskaia cultures. Archaeological context of flint pieces suggests their non-utilitarian meaning. It has been assumed that the burnt flint may reflect a part of some complex ritual connected with funerary practice.

  3. Textile production in the Bronze Age: an assemblage of splindes or bobbins of yarn from the site of Terlinques (Villena, Alicante)

    OpenAIRE

    Jover Maestre, Francisco Javier; López Padilla, Juan Antonio; Machado Yanes, Carmen; Herráez Martín, M. Isabel; Rivera Núñez, Diego; Precioso Arévalo, M. Luisa; Llorach Asunción, Rafael

    2001-01-01

    The archeological field work on the Bronze Age site of Terlinques (Villena, Alicante) has given an exceptional sample of spindles or bobbins of rush fibre of yarn in a room destroyed by a violent fire. A meticulous study of these special objects and their process of analysis and restoration yields new perspectives on knowledge in first stages of textile production during Bronze Age in Eastern Spain.

    Los trabajos arqueológicos que se llevan a cabo en el yacimiento de la Edad...

  4. First-principles calculation of the effects of tetragonal distortions on the Gilbert damping parameter of Co2MnSi

    OpenAIRE

    Pradines, B; Arras, R.; Calmels, L

    2017-01-01

    We present an ab initio study of the influence of the tetragonal distortion, on the static and dynamic (Gilbert damping parameter) magnetic properties of a Co2MnSi crystal. This tetragonal distortion can for instance be due to strain, when Co2MnSi is grown on a substrate with a small lattice mismatch. Using fully relativistic Korringa-Kohn-Rostoker (KKR) calculations, in conjunction with the coherent potential approximation (CPA) to describe atomic disorder and the linear response formalism t...

  5. Hydrothermal degradation of tetragonal ZrO{sub 2} ceramic components used in dental applications; Efeito da degradacao em meio aquoso de componentes ceramicos a base de ZrO{sub 2} tetragonal para uso odontologico

    Energy Technology Data Exchange (ETDEWEB)

    Mukaeda, L.E.; Robin, A.; Taguchi, S.P. [Universidade de Sao Paulo (DEMAR/EEL/USP), Lorena, SP (Brazil). Escola de Engenharia de Lorena. Dept. de Engenharia de Materiais; Santos, C. [ProtMat Materiais Avancados, Guaratingueta, SP (Brazil)

    2009-07-01

    With the evolution of the dental restoration techniques, a considerable growth in the demand of ceramic products occurred. These materials present good strength associated to reliability. In this work, micrometric and nanometric scale tetragonal ZrO{sub 2} blocks were sintered at 1500 deg C-2h and 1350 deg C-2h, respectively, ground and polished. Ceramics with relative density higher than 98% were obtained. The specimens were immersed in hot water (150 deg C), for times ranging from 10h to 30h. The mass variation of the samples was measured and the crystalline phases present before and after the degradation tests were identified by X-ray diffractometry, in order to evaluate the capacity of these ceramics in resisting to aqueous medium exposure. Materials with nanometric structure present higher resistance to degradation than those with micrometric scale, and this interferes in structural stability after the test, and reduces the martensitic transformation. (author)

  6. Caracterização ultra-sônica de materiais ferroelétricos com estrutura perovskita e tungstênio-bronze Ultrasonic characterization of perovskite and tungsten-bronze ferroelectric materials

    Directory of Open Access Journals (Sweden)

    A. Moreno-Gobbi

    2002-03-01

    Full Text Available Atenuação e velocidade ultra-sônicas e, consequentemente, o módulo de Young de cerâmicas ferroelétricas com estrutura do tipo perovskita e tungstênio-bronze foram medidas entre 2,5 e 30 MHz, à temperatura ambiente, utilizando-se a técnica de pulso-eco. Composições com e sem chumbo foram testadas, mostrando que a presença do cátion Pb2+ representa fator importante no comportamento da atenuação. A dependência da atenuação com a freqüência é mais acentuada no caso dos ferroelétricos com estrutura perovskita. As discussões são baseadas nos modelos de espalhamento por grãos/poros em materiais policristalinos.Ultrasonic attenuation and velocity of ferroelectric ceramics with perovskite and tungsten-bronze structures were measured in a range of 2.5 to 30 MHz at room temperature, using the pulse-echo-overlap technique. Lead and non-lead compositions were analyzed, revealing that Pb2+ in the lattice affects the attenuation behavior. The frequency dependence of attenuation is clearly stronger for the lead materials with perovskite structure. The discussions are based on a qualitative analysis of grain/pore scattering models for polycrystalline materials

  7. Magnetic Properties of Tetragonally Distorted Fe3Pt and the Hybrid Structure Fe3Pt/Fe

    Science.gov (United States)

    Sakuma, Akimasa

    1995-11-01

    To investigate the magnetic performance of a hybrid structure oftransition metals, we consider the Fe3Pt/Fe system and examine theeffects both of the tetragonal distortion of L12 type Fe3Pt andthe hybridization with bcc-Fe on the magnetic properties, usingLMTO-ASA method in the framework of LSD. The magnetic moment ofFe3Pthas a maximum stationary value of 8.85 µ B/ cell atc/a=1/\\sqrt{2}. The hypothetical struc-ture of Fe20Pt4 is supposed by combining Fe3Pt of c/a=1/\\sqrt{2} and bcc-Fe lattice. It is predicted that the magnetizationreaches 2.27 T with the magnetic anisotropy constant of 11×105 J/ m3. With using the coherent rotation model formagnetization reversal process, we get maximum energy product(BH) max=10.2 MJ/ m3.

  8. Mongolian “Neolithic” and Early Bronze Age ground stone tools from the northern edge of the Gobi Desert

    Directory of Open Access Journals (Sweden)

    Joan S. Schneider

    2016-10-01

    Full Text Available The transition from the Mongolian Neolithic to the Bronze Age is not well understood. Within Ikh Nart Nature Reserve, over a period of five years, we identified a number of sites with dense surface artefact scatters and features that seem to represent this transition period. Evident in those concentrations are characteristic microblade cores, microblades, “thumbnail" flake scrapers, projectile points, ground stone tools, and stone features of unknown function. Between 2012 and 2014 we collected ground stone artefacts from four sites and sediment samples from three sites. With permission of Mongolian authorities, the artefacts from one site and sediment samples from three sites were sent for botanical analyses to the University of Texas, Austin, Environmental Archaeology Laboratory. Preliminary results indicate that plant remains are present on the ground stone artefacts: dendritic long-cells from a deep pore of one artefact and starch grains from the pores of six of the seven artefacts. These data present the first opportunity to understand what resources “Neolithic” people were processing with ground stone tools in this area and further our opportunity to better understand the little-known “Neolithic”-Early Bronze Age transition period in Central Asia. This paper describes the ground stone artefacts and further explores the results of data retrieved from some of these artefacts.

  9. On Some Mechanical Properties and Wear Behavior of Sintered Bronze Based Composites Reinforced with Some Aluminides Microadditives

    Science.gov (United States)

    Feldshtein, E.; Kiełek, P.; Kiełek, T.; Dyachkova, L.; Letsko, A.

    2017-05-01

    In the paper, the changes in some mechanical properties and wear behavior of CuSn10 sintered bronze and MMCs based on this bronze reinforced with composite ultrafine aluminide powders FeAl/15 % Al2O3, NiAl/15 % Al2O3 and Ti-46Al-8Cr are described. It was observed that the presence of aluminides in the MMCs leads to an increase in the hardness, but the flexural strength may increase or decrease depending on the type of aluminide. The presence of aluminides in the MMC reduces the wear rate considerably. It is decreased in the direction of FeAl/15 % Al2O3 → NiAl/15 % Al2O3 → Ti-46Al-8Cr aluminides and for the best MMC composition the advantage is about 20 times. In the MMCs wear process, micro-craters are formed on the contact surface and it is the principal reason of a decrease in the wear rate.

  10. Effect of high energy milling time of the aluminum bronze alloy obtained by powder metallurgy with niobium carbide addition

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Alexandre Nogueira Ottoboni; Silva, Aline da; Rodrigues, Carlos Alberto; Melo, Mirian de Lourdes Noronha Motta; Rodrigues, Geovani; Silva, Gilbert, E-mail: aottoboni@yahoo.com.br [Universidade Federal de Itajuba (UNIFEI), Itajuba, MG (Brazil)

    2017-05-15

    The aluminum bronze alloy is part of a class of highly reliable materials due to high mechanical strength and corrosion resistance being used in the aerospace and shipbuilding industry. It's machined to produce parts and after its use cycle, it's discarded, but third process is considered expensive and besides not being correct for environment reasons. Thus, reusing this material through the powder metallurgy (PM) route is considered advantageous. The aluminum bronze chips were submitted to high energy ball milling process with 3% of niobium carbide (NbC) addition. The NbC is a metal-ceramic composite with a ductile-brittle behaviour. It was analyzed the morphology of powders by scanning electron microscopy as well as particle size it was determined. X ray diffraction identified the phases and the influence of milling time in the diffractogram patterns. Results indicates that milling time and NbC addition improves the milling efficiency significantly and being possible to obtain nanoparticles. (author)

  11. First Paleoparasitological Report on the Animal Feces of Bronze Age Excavated from Shahr-e Sukhteh, Iran.

    Science.gov (United States)

    Makki, Mahsasadat; Dupouy-Camet, Jean; Sajjadi, Seyed Mansour Seyed; Naddaf, Saied Reza; Mobedi, Iraj; Rezaeian, Mostafa; Mohebali, Mehdi; Mowlavi, Gholamreza

    2017-04-01

    Shahr-e Sukhteh (meaning burnt city in Persian) in Iran is an archeological site dated back to around 3,200-1,800 BC. It is located in Sistan and Baluchistan Province of Iran and known as the junction of Bronze Age trade routes crossing the Iranian plateau. It was appointed as current study area for paleoparasitological investigations. Excavations at this site have revealed various archeological materials since 1967. In the present study, sheep and carnivore coprolites excavated from this site were analyzed by means of rehydration technique using TSP solution for finding helminth eggs. Dicrocoelium dendriticum, Capillaria sp., and Taenia sp. eggs were identified, while some other objects similar to Anoplocephalidae and Toxocara spp. eggs were also retrieved from the samples but their measured parameters did not match those of these species. The present paper illustrates the first paleoparasitological findings of Bronze Age in eastern Iran supporting the economic activities, peopling, and communication as well as the appropriate condition for zoonotic helminthiasis life cycle in Shahr-e Sukhteh archeological site.

  12. High performance bimorph piezoelectric MEMS harvester via bulk PZT thick films on thin beryllium-bronze substrate

    Science.gov (United States)

    Yi, Zhiran; Yang, Bin; Li, Guimiao; Liu, Jingquan; Chen, Xiang; Wang, Xiaolin; Yang, Chunsheng

    2017-07-01

    This letter presents a high performance bimorph piezoelectric MEMS harvester with bulk PZT thick films on both sides of a flexible thin beryllium-bronze substrate via bonding and thinning technologies. The upper and lower PZT layers are thinned down to about 53 μm and 76 μm, respectively, and a commercial beryllium bronze with the thickness of about 50 μm is used as the substrate. The effective volume of this device is 30.6 mm3. The harvester with a tungsten proof mass generated the close-circuit peak-to-peak voltage of 53.1 V, the output power of 0.979 mW, and the power density of 31.99 mW/cm3 with the matching load resistance of 360 kΩ at the applied acceleration amplitude of 3.5 g and the applied frequency of 77.2 Hz. Meanwhile, in order to evaluate the stability, the device was measured continuously under applied acceleration amplitudes of 1.0 g and 3.5 g for one hour and demonstrated a good stability. Then, the harvester was utilized to light up LEDs and about twenty-one serial LEDs were lighted up at resonance under an applied acceleration amplitude of 3.0 g.

  13. Particle size and kind of mica in synthesis of nontoxic bronze and gold pearlescent pigments based on nanoencapsulated hematite

    Directory of Open Access Journals (Sweden)

    Maryam Hosseini-Zori

    2015-12-01

    Full Text Available Nano-encapsulated iron oxide in Zirconium oxide-coated mica pigments are thermally stable,innocuous to human health, non-combustible, and they do not conduct electricity. They could beapplied in several industries such as thermoplastics, cosmetics, food packaging, children toys, paints,automobiles coating, security purposes, and banknotes. Nowadays, they are highly desirable inceramic decoration. In the present study, intensively dark gold to bronze colored mica clay pigments,which were based on mica flakes covered with a layer of nano-iron oxide-Zirconium oxide particles,were prepared by homogeneous precipitation of iron nitrate and Zirconium chloride ammonia in thepresence of mica flakes in two kinds of ore clay-based phlogopite and muscovite minerals. The finalcolor was obtained by thermal annealing of precipitates at a temperature of 800◦C. The pigments werecharacterized by X-Ray Diffraction, Particle size analysis, Scanning electron microscopy,Transmission electron microscopy, X-Ray fluorescence, and Simultaneous thermal analysis. Resultsindicate that nano-encapsulated iron oxide in zirconia particles have been formed on mica flakes andkinds of clay-mica can be related to obtained shade from dark gold to bronze pearl. Higher particlesize of mica flakes about phlogopite type of mica introduced pearl effects with higher L* changes indifferent angles. Muscovite performed higher hue and better pearl effect than phlogopite.

  14. Effects of brooding periods on performance of poults and grow-out small bronze turkeys in hot humid tropical environment.

    Science.gov (United States)

    Nwaodu, Chibuzo Hope; Okoro, Victor Mela Obinna; Uchegbu, Martins Chigozie; Mbajiorgu, Christian Anayochukwu

    2018-01-06

    A study was conducted to determine the effects of varied brooding regimes on the performance of small bronze turkey poults and their grow-outs. One hundred and twenty (n = 120) poults were subjected to four brooding regimes of 0-5, 0-6, 0-7, and 0-8 weeks, designated as T1, T2, T3, and T4. Each brooding regime (treatment) was applied to 3 replicates of 10 poults/replicate in a completely randomized design. The feed intake of T1 poults was higher (P grow-out turkeys in all the production parameters measured, as well as in the feed cost per kilogram weight gain of the treatment groups. This result shows that small bronze-type turkeys brooded from 0 to 8 weeks had higher efficiency in terms of feed intake, FCR, and lower economic costs compared to those brooded from 0 to 5, 0-6, and 0-7 weeks at the poult stage. However, at grow-out stage, the period of brooding did not have any effects on their performance.

  15. The KCaSrTa5O15 photocatalyst with tungsten bronze structure for water splitting and CO2 reduction.

    Science.gov (United States)

    Takayama, Tomoaki; Tanabe, Kentaro; Saito, Kenji; Iwase, Akihide; Kudo, Akihiko

    2014-11-28

    KCaSrTa5O15 with tungsten bronze structure and a band gap of 4.1 eV showed activity for water splitting without cocatalysts. The activity was improved by loading the NiO cocatalyst. The apparent quantum yield of optimized NiO-loaded KCaSrTa5O15 was 2.3% at 254 nm for water splitting. When CO2 gas was bubbled into the reactant aqueous solution, Ag cocatalyst-loaded KCaSrTa5O15 produced CO and H2 as reduction products of CO2 and H2O, respectively, and O2 as an oxidation product of H2O. The carbon source of CO was confirmed to be CO2 molecules by using (13)CO2. The ratio of the number of electrons to that of holes calculated from the amounts of products (CO, H2 and O2) was almost unity. Additionally, the ratio of the turnover number of electrons consumed for CO production to the total number of an Ag atom of the cocatalyst that was the active site for CO2 reduction was 8.6 at 20 h. These results indicate that water was consumed as an electron donor for this photocatalytic CO2 reduction in an aqueous medium. Thus, KCaSrTa5O15 with tungsten bronze structure has arisen as a new photocatalyst that is active for water splitting and CO2 reduction utilizing water as an electron donor.

  16. High-Performance Silver Window Electrodes for Top-Illuminated Organic Photovoltaics Using an Organo-molybdenum Oxide Bronze Interlayer.

    Science.gov (United States)

    Tyler, Martin S; Walker, Marc; Hatton, Ross A

    2016-05-18

    We report an organo-molybdenumn oxide bronze that enables the fabrication of high-performance silver window electrodes for top-illuminated solution processed organic photovoltaics without complicating the process of device fabrication. This hybrid material combines the function of wide-band-gap interlayer for efficient hole extraction with the role of metal electrode seed layer, enabling the fabrication of highly transparent, low-sheet-resistance silver window electrodes. Additionally it is also processed from ethanol, which ensures orthogonality with a large range of solution processed organic semiconductors. The key organic component is the low cost small molecule 3-mercaptopropionic acid, which (i) promotes metal film formation and imparts robustness at low metal thickness, (ii) reduces the contact resistance at the Ag/molybdenumn oxide bronze interface, (iii) and greatly improves the film forming properties. Silver electrodes with a thickness of 8 nm deposited by simple vacuum evaporation onto this hybrid interlayer have a sheet resistance as low as 9.7 Ohms per square and mean transparency ∼80% over the wavelength range 400-900 nm without the aid of an antireflecting layer, which makes them well-matched to the needs of organic photovoltaics and applicable to perovskite photovoltaics. The application of this hybrid material is demonstrated in two types of top-illuminated organic photovoltaic devices.

  17. Direct observation of the core/double-shell architecture of intense dual-mode luminescent tetragonal bipyramidal nanophosphors

    Science.gov (United States)

    Kim, Su Yeon; Jeong, Jong Seok; Mkhoyan, K. Andre; Jang, Ho Seong

    2016-05-01

    Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors--Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4--and the C/D-S structure has been proved by extensive scanning transmission electron microscopy (STEM) analysis. Colloidal LiYF4:Ce,Tb nanophosphors with a tetragonal bipyramidal shape are synthesized for the first time and they show intense DC green light via energy transfer from Ce3+ to Tb3+ under illumination with ultraviolet (UV) light. The LiYF4:Ce,Tb nanophosphors show 65 times higher photoluminescence intensity than LiYF4:Tb nanophosphors under illumination with UV light and the LiYF4:Ce,Tb is adapted into a luminescent shell of the tetragonal bipyramidal C/D-S nanophosphors. The formation of the DC shell on the core significantly enhances UC luminescence from the UC core under irradiation of near infrared light and concurrently generates DC luminescence from the core/shell nanophosphors under UV light. Coating with an inert inorganic shell further enhances the UC-DC dual-mode luminescence by suppressing the surface quenching effect. The C/D-S nanophosphors show 3.8% UC quantum efficiency (QE) at 239 W cm-2 and 73.0 +/- 0.1% DC QE. The designed C/D-S architecture in tetragonal bipyramidal nanophosphors is rigorously verified by an energy dispersive X-ray spectroscopy (EDX) analysis, with the assistance of line profile simulation, using an aberration-corrected scanning transmission electron microscope equipped with a high-efficiency EDX. The feasibility of these C/D-S nanophosphors for transparent display devices is also considered.Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors--Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4--and the C/D-S structure

  18. Regional models of metal production in Western Asia in the Chalcolithic, Early and Middle Bronze Ages

    Directory of Open Access Journals (Sweden)

    Avilova, Liudmila

    2008-06-01

    Full Text Available The objective of this work is the reconstruction and comparative analysis of regional models of metal production in the Chalcolithic, Early and Middle Bronze Ages. The work is based on the statistical analysis of unique computer database on archaeological metal finds from four regions of the Near East: Anatolia, Mesopotamia, the Levant, and Iran. The materials are analysed by four indicators: distribution by the chronological periods, artefacts’ function, proportion of used metals and copper- based alloys. The author presents a series of conclusions concerning the preconditions for the beginnings of metal production in Western Asia and the pioneering role of Iran in its emergence, the important role the piedmont territories played in the development of metal production, the leap-like pattern of production dynamics shown by the periods, and its relation to the spread of a producing economy, long-distance exchange, and the emergence of the early civilizations.

    El objetivo de este trabajo es la reconstrucción y análisis comparativo de modelos regionales de producción metalúrgica del Calcolítico y la Edad del Bronce Inicial y Media. Se basa en el análisis estadístico de una base de datos única sobre hallazgos metálicos de cuatro regiones del Próximo Oriente: Anatolia, Mesopotamia, el Levante e Irán. Los materiales se analizan atendiendo a cuatro variables: períodos cronológicos, función de los artefactos, proporción de los metales usados y las distintas aleaciones del cobre. La autora aporta una serie de conclusiones respecto a las precondiciones para los inicios de la producción metalúrgica en el Oeste Asiático; sobre el papel pionero de Irán en su aparición; la importancia de los piedemontes en su desarrollo; el patrón no continuo que se observa en las dinámicas de producción por periodos; y su relación con la expansión de la economía de producción, el intercambio a larga distancia y la aparición de las

  19. Micromorphological investigation on ring road sediments of the Early Bronze Age site Tell Chuera, Syria

    Science.gov (United States)

    Fritzsch, Dagmar; Thiemeyer, Heinrich

    2010-05-01

    Tell Chuera is an Early Bronze Age settlement mount in NE-Syria close to the Turkish border. With a diameter of almost 1 km and a height of 18 m it is one of the biggest tells in the region between the rivers Balikh and Khabur. In 1958 the structures of the city wall was known first by Orthmann (1990). This city wall was built of air-dried mud bricks. The age of the founding of this construction is not yet clear. The earliest pottery from the place is dated around 2500 BC to 2350 BC. Inside the fortification a road was detected, which was first excavated by Novak (1995). We took sediment monoliths in 2004 from a new trench, which shows the same situation of the road. A geomagnetic prospection, that included the whole site, suggests that the road was part of the planned extension of the lower town and serves as a circular road (Meyer, in prep.). The micromorphological investigation focussed on the question, how the road was used. Did animals have had access to the town? The thin sections show different indications of the anthropogenic influence. In all samples pseudomorphs after straw are visible. In many parts ash, charred wood fragments, bone fragments, melted material and fragments of basalt and flint were observable, too. These materials are typical for sediments in streets (cf. Goldberg & Macphail, 2006). In some parts of the thin sections faecal spherulites and dung remains with faecal spherulites give an idea that ruminants used the road as well as men. Trampling structures support this assumption. Moreover, leaching of calcite, its redeposition in mottles, pseudomycels and concretions, hydromorphic stains and the translocation of silt indicate postdepositional pedogenic processes. Literature Goldberg, P., & Macphail, R. I. (2006). Practical and theoretical geoarchaeology: UK Blackwell Publishing. Meyer, J.-W. (in prep.). Überlegungen zur Siedlungsstruktur - eine erste Analyse der Ergebnisse der geomagnetischen Prospektion. In J.-W. Meyer (Ed.), Ausgrabungen

  20. Robust date for the Bronze Age Avellino eruption (Somma-Vesuvius): 3945 +/-10 calBP (1995 +/- 10 calBC)

    NARCIS (Netherlands)

    Sevink, J.; van Bergen, M.J.; van der Plicht, J.; Feiken, H.; Anastasia, C.; Huizinga, A.

    2011-01-01

    We found Bronze Age lake sediments from the Agro Pontino graben (Central Italy) to contain a thin (2-3 cm) continuous tephra layer composed of lithics, crystals and minor volcanic glass. Tephrochronological and compositional constraints strongly suggest that this layer represents the Avellino pumice

  1. Neutron and X-ray characterisation of the metallurgical properties of a 7th century BC Corinthian-type bronze helmet

    Science.gov (United States)

    Pantos, E.; Kockelmann, W.; Chapon, L. C.; Lutterotti, L.; Bennet, S. L.; Tobin, M. J.; Mosselmans, J. F. W.; Pradell, T.; Salvado, N.; Butí, S.; Garner, R.; Prag, A. J. N. W.

    2005-09-01

    Neutron and synchrotron X-ray diffraction, X-ray fluorescence and FTIR were used to examine a Corinthian-type bronze helmet which is now on display at The Manchester Museum, UK. This type of helmet was manufactured out of a single piece of bronze, probably on a rod-anvil, and like all body-armour it was made to measure. Neutron diffraction sampling of the bronze volume in different areas was used to study the composition, microstructure and crystallographic texture of the alloy in order to draw conclusions about the manufacturing processes. The neutron data revealed the presence of microstrains and non-random distributions of bronze grains hinting at annealing-hammering working cycles in order to harden and shape the alloy. X-ray fluorescence showed that the main body of the helmet is a copper-tin alloy, while the noseguard contains zinc in high abundance. This key compositional difference confirms that the noseguard is not the original but is a modern substitute fabricated for restoration purposes. SR XRD and FTIR from several spots on the head and noseguard identified several surface corrosion products and showed a variation of the Cu-Sn or Cu-Zn percentage compositions, and of the mineral phases. Small samples of corrosion flakes extracted from the outside and inside of the helmet were used to obtain powder XRD patterns.

  2. Confirmation of the immunoreactivity of monoclonal anti-human C-terminal EGFR antibodies in bronze Corydoras Corydoras aeneus (Callichthyidae Teleostei) by Western Blot method.

    Science.gov (United States)

    Mytych, Jennifer; Satora, Leszek; Kozioł, Katarzyna

    2017-12-12

    Bronze corydoras (Corydoras aeneus) uses the distal part of the intestine as accessory respiratory organ. Our previous study showed the presence of epidermal growth factor receptor (EGFR) cytoplasmic domain in the digestive tract of the bronze corydoras. In this study, using Western Blot method, we validated the results presented in the previous research. In detail, results of Western Blot analysis on digestive and respiratory part of bronze corydoras intestine homogenates confirmed the immunoreactivity of anti-cytoplasmic domain (C-terminal) human EGFR antibodies with protein band of approximately 180kDa (EGFR molecular weight). This indicates a high homology of EGFR domain between these species and the possibility of such antibody use in bronze corydoras. Statistically significantly higher EGFR expression was observed in the respiratory part of intestine when compared to the digestive part. This implies higher proliferation activity and angiogenesis of epithelium in this part of intestine, creating conditions for air respiration. Therefore, Corydoras aeneus may be considered as a model organism for the molecular studies of the mechanisms of epithelial proliferation initiation and inhibition depending on hypoxia and normoxia. Copyright © 2017. Published by Elsevier GmbH.

  3. The transmissional and functional context of the lexical lists from Ḫattuša and from the contemporaneous traditions in Late-Bronze-Age Syria

    NARCIS (Netherlands)

    Scheucher, Tobias Simon

    2012-01-01

    The study attempts to reconstruct aspects of the culture and knowledge transfer as involved in the import of cuneiform writing from Mesopotamia to Anatolia and Syria in the Late Bronze Age. It therefore analyzes the manuscripts called 'lexical lists' that were excavated at the Anatolian and Syrian

  4. Robust date for the Bronze Age Avellino eruption (Somma-Vesuvius) : 3945 +/- 10 calBP (1995 +/- 10 calBC)

    NARCIS (Netherlands)

    Sevink, Jan; van Bergen, Manfred J.; van der Plicht, Johannes; Feiken, Hendrik; Anastasia, Carmela; Huizinga, Annika; Maroto, Julià; Vaquero, Manuel; Arrizabalaga, Álvaro; Baena, Javier; Baquedano, Enrique; Jordá, Jesús; Julià, Ramon; Montes, Ramón; Rasines, Pedro; Wood, Rachel; Walsma, A.

    We found Bronze Age lake sediments from the Agro Pontino graben (Central Italy) to contain a thin (2-3 cm) continuous tephra layer composed of lithics, crystals and minor volcanic glass. Tephrochronological and compositional constraints strongly suggest that this layer represents the Avellino pumice

  5. Robust date for the Bronze Age Avellino eruption (Somma-Vesuvius): 3945 +/- 10 calBP (1995 +/- 10 calBC)

    NARCIS (Netherlands)

    Sevink, J.; Bergen, M.J. van; Plicht, J. van der; Feiken, H.; Anastasia, C.; Huizinga, A.

    2011-01-01

    We found Bronze Age lake sediments from the Agro Pontino graben (Central Italy) to contain a thin (2e3 cm) continuous tephra layer composed of lithics, crystals and minor volcanic glass. Tephrochronological and compositional constraints strongly suggest that this layer represents the

  6. Effect of two-stage isothermal annealing on microstructure CuAl10Fe5Ni5 bronze with additions of Si, Cr, Mo, W and C

    Directory of Open Access Journals (Sweden)

    B. P. Pisarek

    2011-07-01

    Full Text Available The aim of this study was to investigate the effect of a two-step isothermal annealing respectively at 1000 ̊C for 30 min, then at the range of 900÷450 ̊C increments 50 ̊C on the microstructure CuAl10 Ni5Fe5 bronze with additions of Si, Cr, Mo, W and C, cast into sand moulds. The study concerned the newly developed species, bronze, aluminium-iron-nickel with additions of Si, Cr, Mo, W and C. In order to determine the time and temperature for the characteristic of phase transitions that occur during heat treatment of the test method was used thermal and derivation analysis (TDA. The study was conducted on cylindrical test castings cast in the mould of moulding sand. It was affirmed that one the method TDA can appoint characteristic for phase transformations points about co-ordinates: τ (s, t ( ̊ C, and to plot out curves TTT for the studied bronze with their use. It was also found that there is a fiveisothermalannealingtemperatureranges significantly altering the microstructure of examined bronze.

  7. Final report of the key comparison CCQM-K98: Pb isotope amount ratios in bronze

    Science.gov (United States)

    Vogl, Jochen; Yim, Yong-Hyeon; Lee, Kyoung-Seok; Goenaga-Infante, Heidi; Malinowskiy, Dmitriy; Ren, Tongxiang; Wang, Jun; Vocke, Robert D., Jr.; Murphy, Karen; Nonose, Naoko; Rienitz, Olaf; Noordmann, Janine; Näykki, Teemu; Sara-Aho, Timo; Ari, Betül; Cankur, Oktay

    2014-01-01

    Isotope amount ratios are proving useful in an ever increasing array of applications that range from studies unravelling transport processes, to pinpointing the provenance of specific samples as well as trace element quantification by using isotope dilution mass spectrometry (IDMS). These expanding applications encompass fields as diverse as archaeology, food chemistry, forensic science, geochemistry, medicine and metrology. However, to be effective tools, the isotope ratio data must be reliable and traceable to enable the comparability of measurement results. The importance of traceability and comparability in isotope ratio analysis has already been recognized by the Inorganic Analysis Working Group (IAWG) within the CCQM. While the requirements for isotope ratio accuracy and precision in the case of IDMS are generally quite modest, 'absolute' Pb isotope ratio measurements for geochemical applications as well as forensic provenance studies require Pb isotope ratio measurements of the highest quality. To support present and future CMCs on isotope ratio determinations, a key comparison was urgently needed and therefore initiated at the IAWG meeting in Paris in April 2011. The analytical task within such a comparison was decided to be the measurement of Pb isotope amount ratios in water and bronze. Measuring Pb isotope amount ratios in an aqueous Pb solution tested the ability of analysts to correct for any instrumental effects on the measured ratios, while the measurement of Pb isotope amount ratios in a metal matrix sample provided a real world test of the whole chemical and instrumental procedure. A suitable bronze material with a Pb mass fraction between 10 and 100 mg•kg-1 and a high purity solution of Pb with a mass fraction of approximately 100 mg•kg-1 was available at the pilot laboratory (BAM), both offering a natural-like Pb isotopic composition. The mandatory measurands, the isotope amount ratios n(206Pb)/n(204Pb), n(207Pb)/n(204Pb) and n(208Pb)/n(204Pb

  8. The influence of wall thickness on the microstructure of bronze BA1055 with the additions of Si, Cr, Mo and/or W

    Directory of Open Access Journals (Sweden)

    B.P. Pisarek

    2008-12-01

    Full Text Available Aluminium bronzes belong to the high-grade constructional materials applied on the put under strongly load pieces of machines, about good sliding, resistant properties on corrosion both in the cast state how and after the thermal processing. It moves to them Cr and Si in the aim of the improvement of their usable proprieties. Additions Mo and/or W were not applied so far in the larger concentration, these elements were introduced to the melts of the copper as the components of modifiers. It was worked out therefore the new kind of bronzes casting including these elements. Make additions to the Cu-Al-Fe-Ni bronze of Si, Cr, Mo and/or W in the rise of these properties makes possible. The investigations of the influence of the wall thickness of the cast on size of crystallites were conducted: the primary phase β and intermetallic phase κ and the width separates of the secondary phase α precipitate at phase boundary. It results from conducted investigations, that in the aluminium bronze BA1055 after simultaneous makes additions Si, Cr, Mo and in the primary phase β it undergoes considerable reducing size. The addition W reduce size of the grain phase β in the thin walls of the cast 3-6 mm, and addition Cr in the range of the thickness of the wall of the cast 3-6 mm it favors to reducing size the phase β, in walls 12-25 mm the growth causes it. The addition Mo does not influence the change of the size of the grain of the β phase significantly. The make addition singly or simultaneously of the Cr, Mo and W to the bronze CuAl10Fe5Ni5Si it influences the decrease of the quantity separates of the phase α on the interface boundary and of width it separates independently from the thickness of the wall of the cast. The simultaneous make addition of the Si, Cr, Mo and W it enlarges the surface of the phase κFe, κMo. The make addition to the bronze CuAl10Fe5Ni5Si of the Cr, Mo or W the quantity of crystallizing hard phase κ enlarges and the

  9. Specific corrosion product on interior surface of a bronze wine vessel with loop-handle and its growth mechanism, Shang Dynasty, China

    Energy Technology Data Exchange (ETDEWEB)

    Li Yang; Bao Zhirong; Wu Taotao [School of Physics and Technology, Center for Electron Microscopy and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072 (China); Jiang, Junchun [Xiaogan Museum, Xiaogan 432000 (China); Chen Guantao [Center for Archaeometry, Wuhan University, Wuhan 430072 (China); Pan Chunxu, E-mail: cxpan@whu.edu.cn [School of Physics and Technology, Center for Electron Microscopy and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072 (China); Center for Archaeometry, Wuhan University, Wuhan 430072 (China)

    2012-06-15

    In this paper, a kind of specific stalactitic product was found on the interior surface of a covered bronze wine vessel with loop-handle (Chinese name is you), which was fabricated in Shang Dynasty (1700 B.C.-1100 B.C.) and now is collected in Xiaogan Museum, Hubei province of China. The microstructures of the product were characterized systematically by using optical microscopy, scanning electron microscope, transmission electron microscope, X-ray diffraction, and Raman microscopy. The experimental results revealed that the product belonged to a kind of malachite with high purity and high crystallinity. The growth of the product was considered to be a possible reason that the vessel was overly airtight within a museum display cabinet besides a lid of the vessel, which made the excess of H{sub 2}O and CO{sub 2} gas concentrations inside the vessel during long-term storage. This corrosion product is very harmful to bronze cultural relics, because of a large amount of copper consumption from the matrix which will reduce its life. The growth mechanism of the specific stalactitic product and the suggestions for preservation of the similar bronze relics in museum were proposed. - Highlights: Black-Right-Pointing-Pointer The stalactitic product was the high purity and good crystallinity malachite. Black-Right-Pointing-Pointer Its growth was related to the excess of H{sub 2}O and CO{sub 2} gas concentrations in museum. Black-Right-Pointing-Pointer It is harmful to the bronzes, because copper will be consumed from the matrix. Black-Right-Pointing-Pointer The suggestions for preservation of the similar bronzes in museum were proposed.

  10. Early atmospheric metal pollution provides evidence for Chalcolithic/Bronze Age mining and metallurgy in Southwestern Europe.

    Science.gov (United States)

    Martínez Cortizas, Antonio; López-Merino, Lourdes; Bindler, Richard; Mighall, Tim; Kylander, Malin E

    2016-03-01

    Although archaeological research suggests that mining/metallurgy already started in the Chalcolithic (3rd millennium BC), the earliest atmospheric metal pollution in SW Europe has thus far been dated to ~3500-3200 cal.yr. BP in paleo-environmental archives. A low intensity, non-extensive mining/metallurgy and the lack of appropriately located archives may be responsible for this mismatch. We have analysed the older section (>2100 cal.yr. BP) of a peat record from La Molina (Asturias, Spain), a mire located in the proximity (35-100 km) of mines which were exploited in the Chalcolithic/Bronze Age, with the aim of assessing evidence of this early mining/metallurgy. Analyses included the determination of C as a proxy for organic matter content, lithogenic elements (Si, Al, Ti) as markers of mineral matter, and trace metals (Cr, Cu, Zn, Pb) and stable Pb isotopes as tracers of atmospheric metal pollution. From ~8000 to ~4980 cal.yr. BP the Pb composition is similar to that of the underlying sediments (Pb 15 ± 4 μg g(-1); (206)Pb/(207)Pb 1.204 ± 0.002). A sustained period of low (206)Pb/(207)Pb ratios occurred from ~4980 to ~2470 cal.yr. BP, which can be divided into four phases: Chalcolithic (~4980-3700 cal.yr. BP), (206)Pb/(207)Pb ratios decline to 1.175 and Pb/Al ratios increase; Early Bronze Age (~3700-3500 cal.yr. BP), (206)Pb/(207)Pb increase to 1.192 and metal/Al ratios remain stable; Late Bronze Age (~3500-2800 cal.yr. BP), (206)Pb/(207)Pb decline to their lowest values (1.167) while Pb/Al and Zn/Al increase; and Early Iron Age (~2800-2470 cal.yr. BP), (206)Pb/(207)Pb increase to 1.186, most metal/Al ratios decrease but Zn/Al shows a peak. At the beginning of the Late Iron Age, (206)Pb/(207)Pb ratios and metal enrichments show a rapid return to pre-anthropogenic values. These results provide evidence of regional/local atmospheric metal pollution triggered by the earliest phases of mining/metallurgy in the area, and reconcile paleo-environmental and

  11. Early atmospheric metal pollution provides evidence for Chalcolithic/Bronze Age mining and metallurgy in Southwestern Europe

    Energy Technology Data Exchange (ETDEWEB)

    Martínez Cortizas, Antonio, E-mail: antonio.martinez.cortizas@usc.es [Departamento de Edafoloxía e Química Agrícola, Facultade de Bioloxía, Universidade de Santiago de Compostela, Campus Sur s/n, Santiago de Compostela (Spain); López-Merino, Lourdes, E-mail: lourdes.lopez-merino@brunel.ac.uk [Institute of Environment, Health and Societies, Brunel University London, UB8 3PH Uxbridge (United Kingdom); Bindler, Richard, E-mail: richard.bindler@umu.se [Department of Ecology and Environmental Science, Umeå University, Umeå (Sweden); Mighall, Tim, E-mail: t.mighall@abdn.ac.uk [Department of Geography & Environment, School of Geosciences, University of Aberdeen, Elphinstone Road, Aberdeen AB24 3UF (United Kingdom); Kylander, Malin E., E-mail: malin.kylander@geo.su.se [Department of Geological Sciences and the Bolin Centre for Climate Research, Stockholm University, SE-10691, Stockholm (Sweden)

    2016-03-01

    Although archaeological research suggests that mining/metallurgy already started in the Chalcolithic (3rd millennium BC), the earliest atmospheric metal pollution in SW Europe has thus far been dated to ~ 3500–3200 cal. yr. BP in paleo-environmental archives. A low intensity, non-extensive mining/metallurgy and the lack of appropriately located archives may be responsible for this mismatch. We have analysed the older section (> 2100 cal. yr. BP) of a peat record from La Molina (Asturias, Spain), a mire located in the proximity (35–100 km) of mines which were exploited in the Chalcolithic/Bronze Age, with the aim of assessing evidence of this early mining/metallurgy. Analyses included the determination of C as a proxy for organic matter content, lithogenic elements (Si, Al, Ti) as markers of mineral matter, and trace metals (Cr, Cu, Zn, Pb) and stable Pb isotopes as tracers of atmospheric metal pollution. From ~ 8000 to ~ 4980 cal. yr. BP the Pb composition is similar to that of the underlying sediments (Pb 15 ± 4 μg g{sup −1}; {sup 206}Pb/{sup 207}Pb 1.204 ± 0.002). A sustained period of low {sup 206}Pb/{sup 207}Pb ratios occurred from ~ 4980 to ~ 2470 cal. yr. BP, which can be divided into four phases: Chalcolithic (~ 4980–3700 cal. yr. BP), {sup 206}Pb/{sup 207}Pb ratios decline to 1.175 and Pb/Al ratios increase; Early Bronze Age (~ 3700–3500 cal. yr. BP), {sup 206}Pb/{sup 207}Pb increase to 1.192 and metal/Al ratios remain stable; Late Bronze Age (~ 3500–2800 cal. yr. BP), {sup 206}Pb/{sup 207}Pb decline to their lowest values (1.167) while Pb/Al and Zn/Al increase; and Early Iron Age (~ 2800–2470 cal. yr. BP), {sup 206}Pb/{sup 207}Pb increase to 1.186, most metal/Al ratios decrease but Zn/Al shows a peak. At the beginning of the Late Iron Age, {sup 206}Pb/{sup 207}Pb ratios and metal enrichments show a rapid return to pre-anthropogenic values. These results provide evidence of regional/local atmospheric metal pollution triggered by the

  12. Prediction of stabilities, mechanical properties and electronic structures of tetragonal 3d transition metal disilicides: A first-principles investigation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Xiaohong, E-mail: zhangxiaohong@hrbeu.edu.cn [College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Wang Zhengping, E-mail: zpwang@hrbeu.edu.cn [College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); College of Science, Harbin Engineering University, Harbin 150001 (China); Qiao Yingjie [College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China)

    2011-08-15

    The phase stabilities, mechanical properties and electronic structures of 3d transition metal disilicides were systematically investigated by first-principles calculations. The results indicated that the crystal volume and melting temperature of the compounds increase at first and then drop again with the filling of electrons on the bonding and anti-bonding states. For tetragonal TiSi{sub 2}, NiSi{sub 2}, CuSi{sub 2} and ZnSi{sub 2}, the calculated formation energies and elastic constants confirmed that they are either thermodynamically unstable or mechanically unstable. According to the electronic structures, it can be identified that almost all the Si-Si (I) and Si-TM (I) bonds (type I) are stronger than the Si-TM (II) and Si-TM (II) (type II) ones. Therefore, the elastic deformation resistance along the <0 0 1> direction for the compounds are expected to be larger than those along the <1 0 0> and <0 1 0> directions, demonstrated by the calculated C{sub 11}, C{sub 33}, E{sub x} (E{sub y}) and E{sub z} values. Despite of the elastic constants and moduli, the results also showed that the Si-Si (I) and Si-TM (I) bonds are very important for elucidating the interfacial behaviors of the {l_brace}0 0 1{r_brace} crystal plane. For tetragonal VSi{sub 2} and CrSi{sub 2}, the Si-Si (I) bonds are half the size of the Si-TM (I) ones, leading to a preferential cleavage of the Si-TM interface, and therefore they show brittle characteristics. However, the situations in FeSi{sub 2} and CoSi{sub 2} are different. The moderate bonding strength of type I bonds and the uniform distributions of electron density on different {l_brace}0 0 1{r_brace} interfaces indicate that slip systems preferentially appear. Therefore, FeSi{sub 2} and CoSi{sub 2} possess excellent ductility.

  13. Reconstructing the Palaeogeographies of a Neolithic - Bronze Age Settlement Mound at Ephesos, Turkey

    Science.gov (United States)

    Ehlers, Lisa; Friederike, Stock; Barbara, Horejs; Helmut, Brückner

    2014-05-01

    Although Ephesos and its surroundings has long been an area of archaeological interest and investigations, the focus has mainly been on sites related to Antiquity and Late Antiquity. Until recently systematic research concerning prehistoric phases of occupation within this region have been lacking. Due to the growing interest in these time periods along the West Anatolian coast, archaeological research projects involving the study of the newly discovered prehistoric settlement mounds located in the vicinity of the prominent ancient city were initiated. The aim of this study was to examine the palaeogeographical and geoarchaeological contexts of the mound (tell), Çukuriçi Höyük, in order to determine the thickness and age of the settlement layers as well as the spatial extent of the tell throughout the different periods of settlement. As additional research to the excavations, 20 sediment cores drilled on and around Çukuriçi Höyük were examined and their physical and geochemical properties as well as existing data were used to reconstruct the palaeoenvironment. The chronostratigraphy relies on AMS-14C ages and findings of diagnostic ceramics; a further attempt was made by luminescence dating. The results reveal that the inhabitants intentionally choose the location due to the beneficial topography, initially, i.e. during Pottery Neolithic times in the early 7th mill. BC, lying upon an elevation within a fertile alluvial plain about 1.5-2 km away from the coast. It seems that during the time of settling (Pottery Neolithic - Early Bronze Age) several rivers flowed in the direct vicinity of the tell. The elevated terrain provided the inhabitants security from the torrents. In addition, the corings reveal that the tell covers an area of about 11,000 m2 and a thickness of settlement layers of c. 8 m. Finally, as a possible result of water management conducted by the inhabitants, sediments related to low-energy depositional conditions are identified at the foot of

  14. Environmental impact of copper mining and metallurgy during the Bronze Age at Kargaly (Orenburg region, Russia

    Directory of Open Access Journals (Sweden)

    Vicent García, Juan Manuel

    2010-12-01

    Full Text Available Kargaly (Orenburg, Russia is a copper-producing region in which two main phases of mining activity have taken place: the 4th-2nd millennia BC and the 18th-20th centuries AD. This article is a comparative study on the impact of those mining episodes in the distribution of the forest resources in the region, aimed to estimate the scale of prehistoric mining and metallurgical works. For that purpose two paleopalinological sequences obtained from natural deposits located in Kargaly are analysed by inferential Statistics and Multivariate Methods. The results are compared both with a regional sampling of recent pollen rain supported by an analytical model of the present day landscape, and with the anthracological data coming from the Late Bronze Age settlement of Gorny 1. Analysis confirm the large scale of the prehistoric mining impact on the forest cover from the beginnings, as well as the strong effect of husbandry once mining works ended. These results allow us to dismiss a climatic change as main explanation for the detected diachronic variability in the palinological record. They also prove the viability of the proposed approach as a means of integrating the paleoenvironmental disciplines in Landscape Archaeology.

    Kargaly (región de Orenburgo, Rusia es una región cuprífera explotada entre los milenios IV y II cal BC y los siglos XVIII y XX d.C. El objetivo del artículo es estudiar comparativamente el impacto de estos episodios mineros en la distribución de los recursos forestales de la región, para aproximar la escala de las operaciones minero-metalúrgicas prehistóricas. Para ello se analizan con métodos estadísticos inferenciales y multivariantes dos secuencias paleopalinológicas procedentes de depósitos naturales de la región y se comparan con un muestreo regional de la lluvia polínica reciente apoyado por un modelo analítico del paisaje actual y con los datos antracol

  15. Stable Carbon Isotope Evidence for Neolithic and Bronze Age Crop Water Management in the Eastern Mediterranean and Southwest Asia

    Science.gov (United States)

    Wallace, Michael P.; Jones, Glynis; Charles, Michael; Fraser, Rebecca; Heaton, Tim H. E.; Bogaard, Amy

    2015-01-01

    In a large study on early crop water management, stable carbon isotope discrimination was determined for 275 charred grain samples from nine archaeological sites, dating primarily to the Neolithic and Bronze Age, from the Eastern Mediterranean and Western Asia. This has revealed that wheat (Triticum spp.) was regularly grown in wetter conditions than barley (Hordeum sp.), indicating systematic preferential treatment of wheat that may reflect a cultural preference for wheat over barley. Isotopic analysis of pulse crops (Lens culinaris, Pisum sativum and Vicia ervilia) indicates cultivation in highly varied water conditions at some sites, possibly as a result of opportunistic watering practices. The results have also provided evidence for local land-use and changing agricultural practices. PMID:26061494

  16. Stable Carbon Isotope Evidence for Neolithic and Bronze Age Crop Water Management in the Eastern Mediterranean and Southwest Asia.

    Directory of Open Access Journals (Sweden)

    Michael P Wallace

    Full Text Available In a large study on early crop water management, stable carbon isotope discrimination was determined for 275 charred grain samples from nine archaeological sites, dating primarily to the Neolithic and Bronze Age, from the Eastern Mediterranean and Western Asia. This has revealed that wheat (Triticum spp. was regularly grown in wetter conditions than barley (Hordeum sp., indicating systematic preferential treatment of wheat that may reflect a cultural preference for wheat over barley. Isotopic analysis of pulse crops (Lens culinaris, Pisum sativum and Vicia ervilia indicates cultivation in highly varied water conditions at some sites, possibly as a result of opportunistic watering practices. The results have also provided evidence for local land-use and changing agricultural practices.

  17. Dating the end of the Greek Bronze Age: a robust radiocarbon-based chronology from Assiros Toumba.

    Directory of Open Access Journals (Sweden)

    Kenneth Wardle

    Full Text Available Over 60 recent analyses of animal bones, plant remains, and building timbers from Assiros in northern Greece form an unique series from the 14th to the 10th century BC. With the exception of Thera, the number of 14C determinations from other Late Bronze Age sites in Greece has been small and their contribution to chronologies minimal. The absolute dates determined for Assiros through Bayesian modelling are both consistent and unexpected, since they are systematically earlier than the conventional chronologies of southern Greece by between 70 and 100 years. They have not been skewed by reference to assumed historical dates used as priors. They support high rather than low Iron Age chronologies from Spain to Israel where the merits of each are fiercely debated but remain unresolved.

  18. Production of low-background CuSn6-bronze for the CRESST dark-matter-search experiment.

    Science.gov (United States)

    Majorovits, B; Kader, H; Kraus, H; Lossin, A; Pantic, E; Petricca, F; Proebst, F; Seidel, W

    2009-01-01

    One of the most intriguing open questions in modern particle physics is the nature of the dark matter in our universe. As hypothetical weakly interacting massive particles (WIMPs) do interact with ordinary matter extremely rarely, their observation requires a very low-background detector environment regarding radioactivity as well as an advanced detector technique that allows for active discrimination of the still present radioactive contaminations. The CRESST experiment uses detectors operating at milli-Kelvin temperature. Energy deposition in the detectors is recorded via the simultaneous measurement of a phonon-mediated signal and scintillation emitted by the CaWO(4) crystal targets. The entire setup is made of carefully selected materials. In this note we report on the development of ultra-pure bronze (CuSn(6)) wire in small quantities for springs and clamps that are currently being used in the CRESST II setup.

  19. Presentation of Andronovsky Costume in Museum Exposition (on materials from Lisakovsk burial mound of the Bronze Age

    Directory of Open Access Journals (Sweden)

    Usmanova Emma R.

    2017-09-01

    Full Text Available The article features an analysis of ancient weaving technologies and women's costume of the Andronovo culture dating back to the Bronze Age. It features a reconstruction of this costume executed by the author on the basis of the discovered remains of woven textile and headwear decoration discovered in burial grounds of Lisakovsk area in the first half of 2nd Millennium B.C. (Kazakhstan, Kostanay Region, Kisakovsk. The preservation of textile base allowed the author to experimentally produce copies of two women's headwear pieces and a vest. As a result, two types of braid adornments were discovrered among grave artifacts. The author substantiates several ideas related to the meaning of the signs and symbols on costume details. As a result of research, the author presents the semantics of headwear corresponding to Andronovo culture in the context of the symbolism of costumes belonging to the traditional peoples of Middle Eurasia.

  20. Mobility during the neolithic and bronze age in northern ireland explored using strontium isotope analysis of cremated human bone.

    Science.gov (United States)

    Snoeck, Christophe; Pouncett, John; Ramsey, Greer; Meighan, Ian G; Mattielli, Nadine; Goderis, Steven; Lee-Thorp, Julia A; Schulting, Rick J

    2016-07-01

    As many individuals were cremated in Neolithic and Bronze Age Ireland, they have not featured in investigations of individual mobility using strontium isotope analysis. Here, we build on recent experiments demonstrating excellent preservation of biogenic (87) Sr/(86) Sr in calcined bone to explore mobility in prehistoric Northern Ireland. A novel method of strontium isotope analysis is applied to calcined bone alongside measurements on tooth enamel to human remains from five Neolithic and Bronze Age sites in Northern Ireland. We systematically sampled modern vegetation around each site to characterize biologically available strontium, and from this calculated expected values for humans consuming foods taken from within 1, 5, 10 and 20 Km catchments. This provides a more nuanced way of assessing human use of the landscape and mobility than the 'local' vs. 'non-local' dichotomy that is often employed. The results of this study 1) provide further support for the reliability of strontium isotope analysis on calcined bone, and 2) demonstrate that it is possible to identify isotopic differences between individuals buried at the same site, with some consuming food grown locally (within 1-5 Km) while others clearly consumed food from up to 50 Km away from their burial place. Hints of patterning emerge in spite of small sample numbers. At Ballynahatty, for instance, those represented by unburnt remains appear to have consumed food growing locally, while those represented by cremated remains did not. Furthermore, it appears that some individuals from Ballynahatty, Annaghmare and Clontygora either moved in the last few years of their life or their cremated remains were brought to the site. These results offer new insights into the choice behind coterminous cremation and inhumation rites in the Neolithic. Am J Phys Anthropol 160:397-413, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  1. Influence of the technology of melting and inoculation preliminary alloy AlBe5 on change of concentration of Al and micro-structure of the bronze CuAl10Ni5Fe4

    Directory of Open Access Journals (Sweden)

    B. Pisarek

    2010-04-01

    Full Text Available Examining was the aim of the work: influence of the permanent temperature 1300°C ± 15°C and changing time of isothermal holding in the range 0÷50 minutes on the melting loss of aluminum in the bronze CuAl10Ni5Fe4; the quantity the slag rafining - covering Unitop BA-1 (0÷1,5% on the effectiveness of the protection of liquid bronze before the oxygenation, the quantity of the preliminary alloy - in-oculant AlBe5 (0÷1,0% on the effective compensation melting loss of aluminum and time of isothermal holding on the effect of the in-oculation of the bronze and the comparison of the effectiveness of the inoculation of the bronze in furnace and in the form. Introduced investigations resulted from the study of the new grades of the Cu-Al-Fe-Ni bronze with additions singly or simultaneously Si, Cr, Mo and/or W, to melting which necessary it is for high temperature and comparatively long time isothermal holding indispensable to the occur of the process of diffusive dissolving the high-melting of the bronze components. High temperature and lengthening the time of isothermal holding the liquid bronze in casting furnace the melting loss of Al influences the growth. Addition the slag of covering-refining Unitop BA-1 in the quantity 1,5% the bronze protects before the melting loss of aluminum by the time of isothermal holding in the temperature 1300°C about 15 minutes. Addition of the preliminary alloy AlBe5 in the quantity 0,6% it assures the effective compensation of the aluminum which melting loss undergoes for the studied parameters of the melting. The effect of the inoculation of the bronze together with diminishes the preliminary alloy AlBe5 with lengthening the time of isothermal hold-ing. Because of this, use of the method of introducing the preliminary alloy it is seems good solution on the inoculation of aluminum bronzes directly to form, unsensitive on the time of isothermal holding the bronze.

  2. Tetragonal Ce-based Ce-Sm(Fe, Co, Ti){sub 12} alloys for permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Cid, Andres; Salazar, Daniel [BCMaterials, Bizkaia Science and Tecnology Park, 48160 Derio (Spain); Gabay, Aleksandr M.; Hadjipanayis, George C. [Department of Physics and Astronomy, University of Delaware, Newark, DE, 19716 (United States); Barandiaran, Jose Manuel [BCMaterials, Bizkaia Science and Tecnology Park, 48160 Derio (Spain); Department of Electricity and Electronics, University Basque Country (UPV/EHU), 48080 Bilbao (Spain)

    2016-12-15

    Abundance and relatively low cost of Ce provide a great incentive for its use in rare-earth permanent magnets. It has been recently reported that the tetragonal Ce(Fe,Co,Ti)12 compounds may exhibit application-worthy intrinsic magnetic properties. In this work the effect of the α-Fe phase formation due to the evaporation of Sm during alloy fabrication has been studied, as a previous step in the attempt to convert the intrinsic magnetic properties into functional properties of a permanent magnet. Ce{sub 0.5}Sm{sub 0.5}Fe{sub 9}Co{sub 2}Ti alloys based on the ThMn12-type crystal structure have been synthesized via melt-spinning with different Sm content. Coercive fields between 2.8 and 1.4 kOe have been found for α-Fe phase contents between 8 and 46% in volume, showing the influence of the α-Fe phase on the coercivity and exchange coupling between the hard and soft phase. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Chemically driven tetragonal-to-monoclinic polymorphic transformation in retrieved ZTA femoral heads from dual mobility hip implants.

    Science.gov (United States)

    Boffelli, M; Doimo, A; Marin, E; Puppulin, L; Zhu, W; Sugano, N; Clarke, I C; Pezzotti, G

    2016-03-01

    Two short-term (two and nine months) retrieved zirconia-toughened alumina (ZTA) femoral heads and nine pristine femoral heads from the same manufacturer have been investigated with respect to their surface stability by means of confocal Raman spectroscopy. Quantitative estimations of monoclinic volume fraction have been carried out in both non-wear and main wear zones of the retrieved heads, which invariantly showed high volume fractions of monoclinic polymorph. In-depth (sub-surface) profiles, non-destructively collected in the main wear zones with the Raman probe in confocal configuration, indeed confirmed that polymorphic transformation was extended down to 100μm below the bearing surface of the femoral heads. Acceleration of tetragonal-to-monoclinic transformation rate leads to unexpectedly high fractions of monoclinic phase within very short-term in-vivo exposures. Phase transformation in-vivo is much more marked than what one could actually predict according to simply simulating a hydrothermal environment in-vitro and could not be simply ascribed to the mechanical stress fields generated during normal service at the bearing surface. Instead, the chemical consequences of metal contamination on the ZTA femoral head surface are shown to play the most detrimental role in phase destabilization. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Stabilisation of late transition metal and noble metal films in hexagonal and body centred tetragonal phases by epitaxial growth

    Energy Technology Data Exchange (ETDEWEB)

    Hueger, E.

    2005-08-26

    In this work ultrathin metallic films with a crystal phase different to their natural bulk structure were produced by hetero-epitaxial growth on metallic substrates. A further aim of this work was to understand the initiation, growth and stability of crystal phase modifications of these films. there exist cases where the films turn beyond the pseudomorphic-growth to a crystal phase different from their natural bulk structure. The present work presents and discusses such a case in addition to the general phenomenon of pseudomorphic-growth. In particular it is shown that metals whose natural phase is face centred cubic (fcc) can be grown in body centred tetragonal (bct) or hexagonal close packed (hcp) phases in the form of thin films on (001) surfaces of appropriate substrates. The growth behavior, electron diffraction analysis, appearance conditions, geometric fit considerations, examples and a discussion of the phase stability of non-covered films and superlattices is given reviewing all epitaxial-systems whose diffraction pattern can be explained by the hexagonal or pseudomorphic bct phase. (orig.)

  5. Load Deflection of Dow Corning SE 1700 Face Centered Tetragonal Direct Ink Write Materials: Effect of Thickness and Filament Spacing

    Energy Technology Data Exchange (ETDEWEB)

    Small, Ward [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Pearson, Mark A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Metz, Tom R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-03-09

    Dow Corning SE 1700 (reinforced polydimethylsiloxane) porous structures were made by direct ink writing (DIW) in a face centered tetragonal (FCT) configuration. The filament diameter was 250 μm. Structures consisting of 4, 8, or 12 layers were fabricated with center-to-center filament spacing (“road width” (RW)) of 475, 500, 525, 550, or 575 μm. Three compressive load-unload cycles to 2000 kPa were performed on four separate areas of each sample; three samples of each thickness and filament spacing were tested. At a given strain during the third loading phase, stress varied inversely with porosity. At 10% strain, the stress was nearly independent of the number of layers (i.e., thickness). At higher strains (20- 40%), the stress was highest for the 4-layer structure; the 8- and 12-layer structures were nearly equivalent suggesting that the load deflection is independent of number of layers above 8 layers. Intra-and inter-sample variability of the load deflection response was higher for thinner and less porous structures.

  6. Photocatalytic performance of freestanding tetragonal zirconia nanotubes formed in H2O2/NH4F/ethylene glycol electrolyte by anodisation of zirconium

    Science.gov (United States)

    Rozana, Monna; Izza Soaid, Nurul; Kian, Tan Wai; Kawamura, Go; Matsuda, Atsunori; Lockman, Zainovia

    2017-04-01

    ZrO2 nanotubes (ZrNTs) were produced by anodisation of zirconium foil in H2O2/NH4F/ethylene glycol electrolyte. The as-anodised foils were then soaked in the anodising electrolyte for 12 h. Soaking weakens the adherence of the anodic layer from the substrate resulting in freestanding ZrNTs (FS-ZrNTs). Moreover, the presence of H2O2 in the electrolyte also aids in weakening the adhesion of the film from the foil, as foil anodised in electrolyte without H2O2 has good film adherence. The as-anodised FS-ZrNTs film was amorphous and crystallised to predominantly tetragonal phase upon annealing at >300 °C. Annealing must, however, be done at degrade methyl orange (MO), whereby 82% MO degradation was observed after 5 h, whereas FS-ZrNTs with a mixture of monoclinic and tetragonal degraded 70% of MO after 5 h.

  7. Exchange-spring like magnetic behavior of the tetragonal Heusler compound Mn2FeGa as a candidate for spin-transfer torque

    Science.gov (United States)

    Gasi, Teuta; Nayak, Ajaya K.; Winterlik, Jürgen; Ksenofontov, Vadim; Adler, Peter; Nicklas, Michael; Felser, Claudia

    2013-05-01

    We report structural, magnetic, and Mössbauer studies of the Heusler compound Mn2FeGa. Theoretical calculations predict that a tetragonal phase in Mn2FeGa could be an interesting candidate for spin torque transfer applications due to the presence of perpendicular magnetic anisotropy. Experimentally, we found that Mn2FeGa crystallizes in a tetragonal structure after annealing at low temperatures (≤400 °C), whereas, it becomes pseudocubic for higher annealing temperatures. The sample annealed at 400 °C shows a high Curie temperature of 650 K and a hard-magnetic behavior. We observed a nonsaturating and exchange-spring type of hysteresis loops, which indicates that the sample contains two different magnetic states. The Mössbauer measurements clearly support the structural and magnetic data. All these properties make the material a potential candidate for spintronic devices, especially in thin films with perpendicular magnetic anisotropy.

  8. Thermoelectric properties of n and p-type cubic and tetragonal XTiO3 (X = Ba,Pb): A density functional theory study

    Science.gov (United States)

    Rahman, Gul; Rahman, Altaf Ur

    2017-12-01

    Thermoelectric properties of cubic (C) and tetragonal (T) BaTiO3 (BTO) and PbTiO3 (PTO) are investigated using density functional theory together with semiclassical Boltzmann's transport theory. Both electron and hole doped BTO and PTO are considered in 300-500 K temperature range. We observed that C-BTO has larger power factor(PF) when doped with holes, whereas n-type carrier concentration in C-PTO has larger PF. Comparing both BTO and PTO, C-PTO has larger figure of merit ZT. Tetragonal distortion reduces the Seebeck coefficient S in n-doped PTO, and the electronic structures revealed that such reduction in S is mainly caused by the increase in the optical band gaps (Γ - Γ and Γ-X).

  9. Superior Properties of Energetically Stable La2/3Sr1/3MnO3/Tetragonal BiFeO3 Multiferroic Superlattices

    KAUST Repository

    Feng, Nan

    2015-04-30

    The superlattice of energetically stable La2/3Sr1/3MnO3 and tetragonal BiFeO3 is investigated by means of density functional theory. The superlattice as a whole exhibits a half-metallic character, as is desired for spintronic devices. The interfacial electronic states and exchange coupling are analyzed in details. We demonstrate that the interfacial O atoms play a key role in controlling the coupling. The higher ferroelectricity of tetragonal BiFeO3 and stronger response to the magnetic moment in La2/3Sr1/3MnO3/BiFeO3 superlattice show a strongly enhanced electric control of the magnetism as compared to the rhombohedral one. Therefore, it is particularly practical interest in the magnetoelectric controlled spintronic devices.

  10. X-ray diffraction study of shock-modified tetragonal phases of SnO[sub 2] and MnO[sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Newcomer, P.; Morosin, B.; Graham, R.A.

    1992-01-01

    X-ray diffraction line-profile analysis on tetragonal forms of Sn02 (cassiterite), Mn02 (pyrolusite), and previously studied Ti02 (rutile), which were subjected to high pressure shock loading, show that residual lattice strain and coherent crystal'' size are a function of shock parameters. An interesting observation on sample of Mn02 concerns the recovery of cubic Mn203 (bixbyite) in the material subjected to 22 GPa, indicating a shock-induced chemical synthesis.

  11. X-ray diffraction study of shock-modified tetragonal phases of SnO{sub 2} and MnO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Newcomer, P.; Morosin, B.; Graham, R.A.

    1992-11-01

    X-ray diffraction line-profile analysis on tetragonal forms of Sn02 (cassiterite), Mn02 (pyrolusite), and previously studied Ti02 (rutile), which were subjected to high pressure shock loading, show that residual lattice strain and coherent ``crystal`` size are a function of shock parameters. An interesting observation on sample of Mn02 concerns the recovery of cubic Mn203 (bixbyite) in the material subjected to 22 GPa, indicating a shock-induced chemical synthesis.

  12. Investigation of fluctuations of the oxygen order in YBa sub 2 Cu sub 3 O sub x near the orthorhombic-to-tetragonal phase transition using mechanical spectroscopy

    CERN Document Server

    Foos, K

    2000-01-01

    given above. YBa-2Cu-3O-x (concentrations x between 6 and 7) has a tetragonal and a number of orthorhombic structures that correspond to different oxygen configurations in the Cu(1) planes. The oxygen atoms in these planes occupy two types of interstitial sites. In the tetragonal phase, both types of sites are occupied with same probability, whereas the occupation probabilities differ in the orthorhombic phases. Thus the tetragonal-to-orthorhombic phase transition is combined with an disorder-to-order transition. It is, at least above 600 K, of second order. At the transition the amplitude and the correlation time of the fluctuations of the oxygen configuration should diverge. This macroscopic yields ferroelastic behavior and critical slowing-down of the inelastic relaxation rate, respectively. This work gives evidences for this behavior. We studied energy dissipation and elastic modulus behavior of YBa-2Cu-3O-x samples by mechanical spectroscopy (temperatures from 400 to 1000 K, vibrating reed technique, fre...

  13. Crystal structure relation between tetragonal and orthorhombic CsAlD{sub 4}: DFT and time-of-flight neutron powder diffraction studies

    Energy Technology Data Exchange (ETDEWEB)

    Bernert, Thomas; Krech, Daniel; Felderhoff, Michael; Weidenthaler, Claudia [Department of Heterogeneous Catalysis, Max-Planck-Institut fuer Kohlenforschung, Muelheim/Ruhr (Germany); Kockelmann, Winfried [Rutherford Appleton Laboratory, Harwell Oxford, Didcot (United Kingdom); Frankcombe, Terry J. [Research School of Chemistry, The Australian National University, Canberra, ACT (Australia); School of Physical, Environmental and Mathematic Sciences, The University of New South Wales, Canberra, ACT (Australia)

    2015-11-15

    The crystal structures of orthorhombic and tetragonal CsAlD{sub 4} were refined from time-of-flight neutron powder diffraction data starting from atomic positions predicted from DFT calculations. The earlier proposed crystal structure of orthorhombic CsAlH{sub 4} is confirmed. For tetragonal CsAlH{sub 4}, DFT calculations predicted a crystal structure in I4{sub 1}/amd as potential minimum structure, while from neutron diffraction studies of CsAlD{sub 4} best refinement is obtained for a disordered structure in the space group I4{sub 1}/a, with a = 5.67231(9) Aa, c = 14.2823(5) Aa. While the caesium atoms are located on the Wyckoff position 4b and aluminium at Wyckoff position 4a, there are two distinct deuterium positions at the Wyckoff position 16f with occupancies of 50 % each. From this structure, the previously reported phase transition between the orthorhombic and tetragonal polymorphs could be explained. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Defect model of a tetragonal Sm sup 3 sup + center found from EPR measurements in CaF sub 2 and SrF sub 2 crystals

    CERN Document Server

    Zheng Wen Chen; Wu Shao Yi; Tang Sheng

    2003-01-01

    The EPR parameters (g factors g sub p sub a sub r sub a sub l sub l sub e sub l , g sub p sub e sub r sub p sub e sub n sub d sub i sub c sub u sub l sub a sub r sub t sub o and hyperfine structure constants A sub p sub a sub r sub a sub l sub l sub e sub l , A sub p sub e sub r sub p sub e sub n sub d sub i sub c sub u sub l sub a sub r sub t sub o) of a tetragonal (C sub 4 sub v) Sm sup 3 sup + center in CaF sub 2 and SrF sub 2 crystals are calculated by considering the crystal-field J-mixing among the ground sup 6 H sub 5 sub / sub 2 , the first excited sup 6 H sub 7 sub / sub 2 and second excited sup 6 H sub 9 sub / sub 2 state multiplets. In the calculations the free-ion and crystal-field parameters of the tetragonal Sm sup 3 sup + -F sup - center obtained from polarized laser-selective excitation spectroscopy are used. The calculated results suggest that the tetragonal Sm sup 3 sup + -F sup - center is the Sm sup 3 sup + center found by later EPR measurements. The g factors g sub p sub a sub r sub a sub...

  15. First principles study of the structural and electronic properties of double perovskite Ba{sub 2}YTaO{sub 6} in cubic and tetragonal phases

    Energy Technology Data Exchange (ETDEWEB)

    Deluque Toro, C.E., E-mail: deluquetoro@gmail.com [Grupo de Nuevos Materiales, Universidad Popular del Cesar, Valledupar (Colombia); Rodríguez M, Jairo Arbey [Grupo de Estudios de Materiales—GEMA, Departamento de Física, Universidad Nacional de Colombia, AA 5997 Bogotá DC (Colombia); Landínez Téllez, D.A. [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, AA 5997 Bogotá DC (Colombia); Moreno Salazar, N.O. [Departamento de Física, Universidade Federal de Sergipe (Brazil); Roa-Rojas, J. [Grupo de Física de Nuevos Materiales, Departamento de Física, Universidad Nacional de Colombia, AA 5997 Bogotá DC (Colombia)

    2014-12-15

    The Ba{sub 2}YTaO{sub 6} double perovskite presents a transition from cubic (Fm−3m) to tetragonal structure (I4/m) at high temperature. In this work, we present a detailed study of the structural and electronic properties of the double perovskite Ba{sub 2}YTaO{sub 6} in space group Fm−3m and I4/m. Calculations were made with the Full-Potential Linear Augmented Plane Wave method (FP-LAPW) within the framework of the Density Functional Theory (DFT) with exchange and correlation effects in the Generalized Gradient (GGA) and Local Density (LDA) approximations. From the minimization of energy as a function of volume and the fitting of the Murnaghan equation some structural characteristics were determined as, for example, total energy, lattice parameter (a=8.50 Å in cubic phase and a=5.985 Å and c=8.576 Å in tetragonal), bulk modulus (135.6 GPa in cubic phase and 134.1 GPa in tetragonal phase) and its derivative. The study of the electronic characteristics was performed from the analysis of the electronic density of states (DOS). We find a non-metallic behavior for this with a direct band gap of approximately 3.5 eV and we found that the Ba{sub 2}YTaO{sub 6} (I4/m) phase is the most stable one. {sup ©} 2013 Elsevier Science. All rights reserved.

  16. Endogenous Retroviral Insertions Indicate a Secondary Introduction of Domestic Sheep Lineages to the Caucasus and Central Asia between the Bronze and Iron Age

    Directory of Open Access Journals (Sweden)

    Oskar Schroeder

    2017-06-01

    Full Text Available Sheep were one of the first livestock species domesticated by humans. After initial domestication in the Middle East they were spread across Eurasia. The modern distribution of endogenous Jaagsiekte sheep retrovirus insertions in domestic sheep breeds suggests that over the course of millennia, successive introductions of improved lineages and selection for wool quality occurred in the Mediterranean region and most of Asia. Here we present a novel ancient DNA approach using data of endogenous retroviral insertions in Bronze and Iron Age domestic sheep from the Caucasus and Pamir mountain areas. Our findings support a secondary introduction of wool sheep from the Middle East between the Late Bronze Age and Iron Age into most areas of Eurasia.

  17. Endogenous Retroviral Insertions Indicate a Secondary Introduction of Domestic Sheep Lineages to the Caucasus and Central Asia between the Bronze and Iron Age.

    Science.gov (United States)

    Schroeder, Oskar; Benecke, Norbert; Frölich, Kai; Peng, Zuogang; Kaniuth, Kai; Sverchkov, Leonid; Reinhold, Sabine; Belinskiy, Andrey; Ludwig, Arne

    2017-06-20

    Sheep were one of the first livestock species domesticated by humans. After initial domestication in the Middle East they were spread across Eurasia. The modern distribution of endogenous Jaagsiekte sheep retrovirus insertions in domestic sheep breeds suggests that over the course of millennia, successive introductions of improved lineages and selection for wool quality occurred in the Mediterranean region and most of Asia. Here we present a novel ancient DNA approach using data of endogenous retroviral insertions in Bronze and Iron Age domestic sheep from the Caucasus and Pamir mountain areas. Our findings support a secondary introduction of wool sheep from the Middle East between the Late Bronze Age and Iron Age into most areas of Eurasia.

  18. Research in the type of economy and lifestyle of the Volga-Manych steppe population in the Bronze Age: controversial issues

    Directory of Open Access Journals (Sweden)

    Ochir-Goryaeva Maria A.

    2015-06-01

    Full Text Available The article deals with the development of scientific views and ideas concerning the cultural and economic type of left-bank Lower Volga region population in the Bronze Age. The study of the problem in its historical aspect makes it possible for the author to distinguish the following three stages: 1 the formation of the views about sedentary economy (1935–1955; 2 development of the nomadic cattle-breeding culture theory (1955–1977; 3 the period of parallel development of both theories (since 1977. Historiographical survey shows that the results of the study of the Volga-Manych steppe Bronze Age culture were based on the finds from funerary sites (barrows only, which reflect religious ideas rather than the real economic system and lifestyle. The settlements discovered in the steppe were traditionally attributed to the “seasonal camp of mobile pastoralists”, due to their small proportions and poor cultural layer. They remained practically unexplored and unpublished. According to the author, it is necessary to alter this approach to similar vital activity traces in the steppe regions. Moreover, the mapping of the Iron Age funerary sites allowed the author to notice that their geographical position is fundamentally different from the Bronze Age ones. This fact may indicate a different way of life. The distribution of the Early Iron Age nomadic barrows is identical with 17th–18th centuries winter camps left by the nomadic Kalmyks, while the distribution of the Bronze Age barrows aligns with the Russian peasant settlements of the end of 18th – 19th centuries.

  19. Modeling ferroelectric film properties and size effects from tetragonal interlayer in Hf1-xZrxO2 grains

    Science.gov (United States)

    Künneth, Christopher; Materlik, Robin; Kersch, Alfred

    2017-05-01

    Size effects from surface or interface energy play a pivotal role in stabilizing the ferroelectric phase in recently discovered thin film Zirconia-Hafnia. However, sufficient quantitative understanding has been lacking due to the interference with the stabilizing effect from dopants. For the important class of undoped Hf1-xZrxO2, a phase stability model based on free energy from Density functional theory (DFT) and surface energy values adapted to the sparse experimental and theoretical data has been successful to describe key properties of the available thin film data. Since surfaces and interfaces are prone to interference, the predictive capability of the model is surprising and directs to a hitherto undetected, underlying reason. New experimental data hint on the existence of an interlayer on the grain surface fixed in the tetragonal phase possibly shielding from external influence. To explore the consequences of such a mechanism, we develop an interface free energy model to include the fixed interlayer, generalize the grain model to include a grain radius distribution, calculate average polarization and permittivity, and compare the model with available experimental data. Since values for interface energies are sparse or uncertain, we obtain its values from minimizing the least square difference between predicted key parameters to experimental data in a global optimization. Since the detailed values for DFT energies depend on the chosen method, we repeat the search for different computed data sets and come out with quantitatively different but qualitatively consistent values for interface energies. The resulting values are physically very reasonable and the model is able to give qualitative prediction. On the other hand, the optimization reveals that the model is not able to fully capture the experimental data. We discuss possible physical effects and directions of research to possibly close this gap.

  20. Facile synthesis of tetragonal columnar-shaped TiO2 nanorods for the construction of sensitive electrochemical glucose biosensor.

    Science.gov (United States)

    Yang, Zhanjun; Tang, Yan; Li, Juan; Zhang, Yongcai; Hu, Xiaoya

    2014-04-15

    A tetragonal columnar-shaped TiO2 (TCS-TiO2) nanorods are synthesized via a facile route for the immobilization of glucose oxidase (GOx). A novel electrochemical glucose biosensor is constructed based on the direct electrochemistry of GOx at TCS-TiO2 modified glassy carbon electrode. The fabricated biosensor is characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, electrochemical impedance spectra and cyclic voltammetry. The immobilized enzyme molecules on TCS-TiO2 nanorods retain its native structure and bioactivity and show a surface controlled, quasi-reversible and fast electron transfer process. The TCS-TiO2 nanorods have large surface area and provide a favorable microenvironment for enhancing the electron transfer between enzyme and electrode surface. The constructed glucose biosensor shows wide linear range from 5.0×10(-6) to 1.32×10(-3) M with a high sensitivity of 23.2 mA M(-1) cm(-2). The detection limit is calculated to be 2.0×10(-6) M at signal-to-noise of 3. The proposed glucose biosensor also exhibits excellent selectivity, good reproducibility, and acceptable operational stability. Furthermore, the biosensor can be successfully applied in the detection of glucose in serum sample at the applied potential of -0.50 V. The TCS-TiO2 nanorods provide an efficient and promising platform for the immobilization of proteins and development of excellent biosensors. © 2013 Published by Elsevier B.V.

  1. Tetragonal-cubic phase boundary in nanocrystalline ZrO{sub 2}-Y{sub 2}O{sub 3} solid solutions synthesized by gel-combustion

    Energy Technology Data Exchange (ETDEWEB)

    Fabregas, Ismael O. [CINSO (Centro de Investigaciones en Solidos), CITEFA-CONICET, J.B. de La Salle 4397, 1603 Villa Martelli, Pcia. de Buenos Aires (Argentina); Craievich, Aldo F.; Fantini, Marcia C.A. [Instituto de Fisica, Universidade de Sao Paulo, Travessa R da Rua do Matao, No. 187, Cidade Universitaria, 05508-900 Sao Paulo (Brazil); Millen, Ricardo P.; Temperini, Marcia L.A. [Instituto de Quimica, Universidade de Sao Paulo, Avenida Prof. Lineu Prestes 748, Cidade Universitaria, 05508-900 Sao Paulo (Brazil); Lamas, Diego G., E-mail: dlamas@uncoma.edu.ar [CINSO (Centro de Investigaciones en Solidos), CITEFA-CONICET, J.B. de La Salle 4397, 1603 Villa Martelli, Pcia. de Buenos Aires (Argentina); Laboratorio de Caracterizacion de Materiales, Facultad de Ingenieria, Universidad Nacional del Comahue, Buenos Aires 1400, (8300) Neuquen Capital, Prov. de Neuquen (Argentina)

    2011-04-21

    Research highlights: > Gel-combustion synthesis yields compositionally homogeneous, single-phased ZrO{sub 2}-Y{sub 2}O{sub 3} nanopowders, that exhibit the presence at room temperature of three different phases depending on Y{sub 2}O{sub 3} content, namely two tetragonal forms (t' and t'') and the cubic phase. > Phase identification can be achieved by synchrotron XPD (SXPD) and Raman spectroscopy since the tetragonal forms and the cubic phase can be distinguished by these techniques. > The crystallographic features of ZrO{sub 2}-Y{sub 2}O{sub 3} nanopowders were determined by SXPD. They are similar to those reported by Yashima and coworkers for compositionally homogeneous materials containing larger (micro)crystals. However, the lattice parameters are slightly different and the axial ratios c/a of our t' samples are smaller than those reported by these authors. > Compositional t'/t'' and t''/cubic phase boundaries are located at (9 {+-} 1) and (10.5 {+-} 0.5) mol% Y{sub 2}O{sub 3}, respectively. > For the whole series of nanocrystalline ZrO{sub 2}-Y{sub 2}O{sub 3} solid solutions studied in the present work, no evidences of the presence of a mixture of phases - as reported by Yashima and coworkers for microcrystalline solid solutions - were detected. - Abstract: By means of synchrotron X-ray powder diffraction (SXPD) and Raman spectroscopy, we have detected, in a series of nanocrystalline and compositionally homogeneous ZrO{sub 2}-Y{sub 2}O{sub 3} solid solutions, the presence at room temperature of three different phases depending on Y{sub 2}O{sub 3} content, namely two tetragonal forms and the cubic phase. The studied materials, with average crystallite sizes within the range 7-10 nm, were synthesized by a nitrate-citrate gel-combustion process. The crystal structure of these phases was also investigated by SXPD. The results presented here indicate that the studied nanocrystalline ZrO{sub 2}-Y{sub 2}O{sub 3} solid

  2. Strength of the Bond of Structural Steel S235JR to Bronze SAE660 Produced by Casting in Pre-Mold

    Directory of Open Access Journals (Sweden)

    Zaheri M.

    2017-09-01

    Full Text Available Different methods are used for production of bronze bearings. In terms of technical specifications, the success of each of these methods depends on the bond’s strength and in terms of economic, the production method is important. In this study, the aim is to study the strength and microstructure of steel-bronze thrust bearing bond that has been produced through the casting using pre-mold. In this study, in order to bond, the raw metals are chemically washed with sulfuric acid solution for five minutes at first. Then, the molten bronze SAE660 is cast in a structural steel S235JR pre-mold. The bond’s strength has been measured using the shear test three times; the measurement of bond’s length has been done using field emission scanning electron microscope (FESEM. The results indicate that the strength of the bond is at least 94.8 MPa and bond’s length is 0.45 micrometers. Therefore, this method was successful for trust bearing application.

  3. Particular ceramic forms in the central Balkan and northern shores of the Aegean sea in the late bronze age

    Directory of Open Access Journals (Sweden)

    Bulatović Aleksandar

    2011-01-01

    Full Text Available This paper deals with the appearance and development of particular ceramic forms that were prevalent on the wider territory from the lower Danube to the northern shores of the Aegean sea during the middle and Late Bronze Age. These forms relate to globular beakers, pear shaped vessels with everted rims with arch shaped handles, cups with handles with plastic applications on their upper surface, etc. Particular attention is devoted to the phenomenon of globular beakers of the LBA in the valleys of Varder, Mesta and Struma rivers. All information collected primarily through analysis of stylistic-typological characteristics of ceramics of the middle and Late Bronze Age - that took into account ritual burials, layout of settlements, trade routes and climactic conditions during that period - points to population movements from the north to the south already by the LBA, i.e. in 15th century BC. These movements contributed to the creation of particular cultural groups in the LBA in the central Balkans, such as the Brnjica cultural group. However, these movements cannot be clearly linked to the so-called Aegean Migration, and for this reason their character and chronology are subject to debate. Ultimately it can be concluded that beakers of the Zimnicea -Cherkovna-Plovdiv type appeared in the late Bronze Age in the Vlasine depression and the Danube valley through the evolution of beaker forms of cultural groups of earlier periods. Almost contemporaneously, during LBA, a variant of this ceramic form, richly ornamented (mostly with spirals and similar in manner to the cultural group Dubovac-Žuto Brdo-Grla Mare- Krna, appeared in the LBA culture in northern Greece. Clearly this stylistic mannerism, with spirals as characteristic elements, spread relatively quickly through successive migrations in the period of 15th-14th century BC, toward the south of the Balkan Peninsula, thus covering the wider territory from the southern tip of the Carpathian mountains

  4. Metal finds at the Middle and Late Bronze Age settlement of Scoglio del Tonno (Taranto, Apulia: results of archaeometallurgical analyses

    Directory of Open Access Journals (Sweden)

    Bietti Sestieri, Anna Maria

    2010-12-01

    Full Text Available Scoglio del Tonno (Taranto is a settlement with a strategic location in one of the best natural harbours of the Italian Peninsula. During the Late Bronze Age it was an emporion, a privileged and permanent landing place for ships sailing between the Aegean and Italian Peninsulas. Crucibles and a number of metal artefacts were found during its excavation (1899, Quagliati 1900; Säflund 1939; this work reports the quantitative analysis of these metal artefacts by energy dispersive X-ray fluorescence. All are made of copper alloys except for one piece, an eyelet pin made of a gold-silver-copper alloy. The examination of these objects and the analytical data obtained help reconstruct the functions of this site. Metal was systematically accumulated at Scoglio del Tonno, presumably to be shipped towards the eastern Mediterranean. The site highlights the exponential increase in northern Italian metal production during the Recent Bronze Age (ca. 14th-13th c. BC.

    Scoglio del Tonno (Taranto es un yacimiento con una posición estratégica sobre uno de los mejores puertos naturales de la península italiana. Durante el Bronce Tardío fue un emporion, lugar permanente de contactos entre el Egeo y la península italiana. Crisoles y diversos objetos de metal recuperados en las antiguas excavaciones (1899 han sido recientemente analizados con ED-XRF. Excepto una pieza (una aguja de una aleación de oro, plata y cobre, todos los objetos son aleaciones de base cobre. El estudio de los objetos de metal, incluido los datos de su composición, aporta elementos útiles para una reconstrucción de las funciones de este lugar. En Scoglio del Tonno el metal era sistemáticamente almacenado, presumiblemente para ser enviado hacia el Mediterráneo oriental. El yacimiento ilustra también el aumento exponencial de la producción de metal en el norte de Italia durante el Bronce Reciente (siglos XIV y XIII a.C..

  5. Archaeometric analysis of Roman bronze coins from the Magna Mater temple using solid-state voltammetry and electrochemical impedance spectroscopy.

    Science.gov (United States)

    Di Turo, Francesca; Montoya, Noemí; Piquero-Cilla, Joan; De Vito, Caterina; Coletti, Fulvio; Favero, Gabriele; Doménech-Carbó, Antonio

    2017-02-22

    Voltammetry of microparticles (VMP) and electrochemical impedance spectroscopy (EIS) techniques, complemented by SEM-EDX and Raman spectroscopy, were applied to a set of 15 Roman bronze coins and one Tessera from the temple of Magna Mater (Rome, Italy). The archaeological site, dated back between the second half and the end of the 4th century A.D., presented a complicated stratigraphic context. Characteristic voltammetric patterns for cuprite and tenorite for sub-microsamples of the corrosion layers of the coins deposited onto graphite electrodes in contact with 0.10 M HClO4 aqueous solution yielded a grouping of the coins into three main groups. This grouping was confirmed and refined using EIS experiments of the coins immersed in air-saturated mineral water using the reduction of dissolved oxygen as a redox probe. The electrochemical grouping of coins corroborated the complex stratigraphy of the archaeological site and, above all, the reuse of the coins during the later periods due to the economic issues related to the fall of the Roman Empire. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Oxygen isotope in archaeological bioapatites from India: Implications to climate change and decline of Bronze Age Harappan civilization.

    Science.gov (United States)

    Sarkar, Anindya; Mukherjee, Arati Deshpande; Bera, M K; Das, B; Juyal, Navin; Morthekai, P; Deshpande, R D; Shinde, V S; Rao, L S

    2016-05-25

    The antiquity and decline of the Bronze Age Harappan civilization in the Indus-Ghaggar-Hakra river valleys is an enigma in archaeology. Weakening of the monsoon after ~5 ka BP (and droughts throughout the Asia) is a strong contender for the Harappan collapse, although controversy exists about the synchroneity of climate change and collapse of civilization. One reason for this controversy is lack of a continuous record of cultural levels and palaeomonsoon change in close proximity. We report a high resolution oxygen isotope (δ(18)O) record of animal teeth-bone phosphates from an archaeological trench itself at Bhirrana, NW India, preserving all cultural levels of this civilization. Bhirrana was part of a high concentration of settlements along the dried up mythical Vedic river valley 'Saraswati', an extension of Ghaggar river in the Thar desert. Isotope and archaeological data suggest that the pre-Harappans started inhabiting this area along the mighty Ghaggar-Hakra rivers fed by intensified monsoon from 9 to 7 ka BP. The monsoon monotonically declined after 7 ka yet the settlements continued to survive from early to mature Harappan time. Our study suggests that other cause like change in subsistence strategy by shifting crop patterns rather than climate change was responsible for Harappan collapse.

  7. A Bronze Age Pre-Historic Dolmen: Laser Cleaning Techniques of Paintings and Graffiti (The Bisceglie Dolmen Case Study)

    Science.gov (United States)

    Daurelio, G.

    The whole building was included and covered by an elliptical plan tumulus as reported for other similar monuments situated in the same territory of BISCEGLIE and GIOVINAZZO (in South of Italy). The monument was built by a community established in that area to mark their territory. It has a typical funerary character (funeral urn) and it was destined to the collective sepulture in the Middle Bronze Age, as indicated by the ceramic finds, accompanying the rich dead men, copper objects and ornaments, bones and amber recovered inside together with human rests. Degradation Mapping and Laser Cleaning with Photographs, during and after the process in-situ were carried out. Black incrustations and writings (by some different felt pens, marking pens, permanent black and colored ink pigments — fluorescent and no, as well as permanent text liner markings and spayed black paint) were cleaned by using a portable Nd:YAG Laser (λ 1.06 μm — 0.53 μm, in N-Mode and Q-Switch Mode, Laser pulse duration 150 μs or 6ns — f 1 to 10Hz — E max. 500 mJ per pulse in 1st harmonic and 200 mJ per pulse in 2nd harmonic). So, according to the different ink types three different laser cleaning techniques were used.

  8. Effect of Post Heat Treatment on the Microstructure and Microhardness of Friction Stir Processed NiAl Bronze (NAB Alloy

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    Yuting Lv

    2015-09-01

    Full Text Available NiAl bronze (NAB alloy is prepared by using friction stir processing (FSP technique at a tool rotation rate of 1200 rpm and a traverse speed of 150 mm/min. A post heat treatment is performed at the temperature of 675 °C. The effect of heat treatment on the microstructure and microhardness is studied. The results show that the microstructure of the FSP NAB alloy consists of high density dislocations, retained β phase (β′ phase and recrystallized grains. When annealed at 675 °C, discontinuous static recrystallization (DSRX takes place. The content of β′ phase gradually decreases and fine κ phase is precipitated. After annealing for 2 h, both the microhardness of the FSP sample in the stir zone (SZ and the difference in hardness between the SZ and base metal decrease due to the reduction of the dislocation density and β′ phase, accompanying recrystallized grain coarsening. With further increasing of the annealing time to 4 h, the aforementioned difference in hardness nearly disappears.

  9. A piezoelectric micro generator worked at low frequency and high acceleration based on PZT and phosphor bronze bonding

    Science.gov (United States)

    Tang, Gang; Yang, Bin; Hou, Cheng; Li, Guimiao; Liu, Jingquan; Chen, Xiang; Yang, Chunsheng

    2016-12-01

    Recently, piezoelectric energy harvesters (PEHs) have been paid a lot of attention by many researchers to convert mechanical energy into electrical and low level vibration. Currently, most of PEHs worked under high frequency and low level vibration. In this paper, we propose a micro cantilever generator based on the bonding of bulk PZT wafer and phosphor bronze, which is fabricated by MEMS technology, such as mechanical chemical thinning and etching. The experimental results show that the open-circuit output voltage, output power and power density of this fabricated prototype are 35 V, 321 μW and 8664 μW cm-3 at the resonant frequency of 100.8 Hz, respectively, when it matches an optimal loading resistance of 140 kΩ under the excitation of 3.0 g acceleration. The fabricated micro generator can obtain the open-circuit stable output voltage of 61.2 V when the vibration acceleration arrives at 7.0 g. Meanwhile, when this device is pasted on the vibrating vacuum pump, the output voltage is about 11 V. It demonstrates that this novel proposed device can scavenge high vibration level energy at low frequency for powering the inertial sensors in internet of things application.

  10. Evidence that a West-East admixed population lived in the Tarim Basin as early as the early Bronze Age

    Directory of Open Access Journals (Sweden)

    Zhang Quanchao

    2010-02-01

    Full Text Available Abstract Background The Tarim Basin, located on the ancient Silk Road, played a very important role in the history of human migration and cultural communications between the West and the East. However, both the exact period at which the relevant events occurred and the origins of the people in the area remain very obscure. In this paper, we present data from the analyses of both Y chromosomal and mitochondrial DNA (mtDNA derived from human remains excavated from the Xiaohe cemetery, the oldest archeological site with human remains discovered in the Tarim Basin thus far. Results Mitochondrial DNA analysis showed that the Xiaohe people carried both the East Eurasian haplogroup (C and the West Eurasian haplogroups (H and K, whereas Y chromosomal DNA analysis revealed only the West Eurasian haplogroup R1a1a in the male individuals. Conclusion Our results demonstrated that the Xiaohe people were an admixture from populations originating from both the West and the East, implying that the Tarim Basin had been occupied by an admixed population since the early Bronze Age. To our knowledge, this is the earliest genetic evidence of an admixed population settled in the Tarim Basin.

  11. Evidence that a West-East admixed population lived in the Tarim Basin as early as the early Bronze Age.

    Science.gov (United States)

    Li, Chunxiang; Li, Hongjie; Cui, Yinqiu; Xie, Chengzhi; Cai, Dawei; Li, Wenying; Mair, Victor H; Xu, Zhi; Zhang, Quanchao; Abuduresule, Idelisi; Jin, Li; Zhu, Hong; Zhou, Hui

    2010-02-17

    The Tarim Basin, located on the ancient Silk Road, played a very important role in the history of human migration and cultural communications between the West and the East. However, both the exact period at which the relevant events occurred and the origins of the people in the area remain very obscure. In this paper, we present data from the analyses of both Y chromosomal and mitochondrial DNA (mtDNA) derived from human remains excavated from the Xiaohe cemetery, the oldest archeological site with human remains discovered in the Tarim Basin thus far. Mitochondrial DNA analysis showed that the Xiaohe people carried both the East Eurasian haplogroup (C) and the West Eurasian haplogroups (H and K), whereas Y chromosomal DNA analysis revealed only the West Eurasian haplogroup R1a1a in the male individuals. Our results demonstrated that the Xiaohe people were an admixture from populations originating from both the West and the East, implying that the Tarim Basin had been occupied by an admixed population since the early Bronze Age. To our knowledge, this is the earliest genetic evidence of an admixed population settled in the Tarim Basin.

  12. A piezoelectric micro generator worked at low frequency and high acceleration based on PZT and phosphor bronze bonding

    Science.gov (United States)

    Tang, Gang; Yang, Bin; Hou, Cheng; Li, Guimiao; Liu, Jingquan; Chen, Xiang; Yang, Chunsheng

    2016-01-01

    Recently, piezoelectric energy harvesters (PEHs) have been paid a lot of attention by many researchers to convert mechanical energy into electrical and low level vibration. Currently, most of PEHs worked under high frequency and low level vibration. In this paper, we propose a micro cantilever generator based on the bonding of bulk PZT wafer and phosphor bronze, which is fabricated by MEMS technology, such as mechanical chemical thinning and etching. The experimental results show that the open-circuit output voltage, output power and power density of this fabricated prototype are 35 V, 321 μW and 8664 μW cm−3 at the resonant frequency of 100.8 Hz, respectively, when it matches an optimal loading resistance of 140 kΩ under the excitation of 3.0 g acceleration. The fabricated micro generator can obtain the open-circuit stable output voltage of 61.2 V when the vibration acceleration arrives at 7.0 g. Meanwhile, when this device is pasted on the vibrating vacuum pump, the output voltage is about 11 V. It demonstrates that this novel proposed device can scavenge high vibration level energy at low frequency for powering the inertial sensors in internet of things application. PMID:27929139

  13. Foreign elites from the Oxus civilization? A craniometric study of anomalous burials from Bronze Age Tepe Hissar.

    Science.gov (United States)

    Hemphill, B E

    1999-12-01

    Discovery of a small number of individuals in the Period III necropolis at the large northern Iranian Bronze Age site of Tepe Hissar directly associated with a complex of imported artifacts raises the question of whether these individuals represent elites who had access to these exotic commodities, or an imposed foreign elite that may have brought these unusual artifacts from their homelands. The source of the atypical objects is believed to be the Oxus civilization of central Asia. This study investigates the identity of these individuals by employing canonical discriminant function analysis of 20 craniometric variables among 174 adult males from Tepe Hissar Period III and Oxus civilization males from Sapalli tepe and Djarkutan. Dicriminant function analysis provides a strong separation between Tepe Hissar Period III males and Oxus civilization males and a high level of correct assignation by sample (95.8%). Imposition of the five males associated with imported central Asian artifacts from the Period III necropolis indicates that the majority (4/5) are phenetically indistinguishable from other Period III Tepe Hissar males. The results indicate that these individuals most likely represent local elite inhabitants of Tepe Hissar, rather than the presence of an imposed foreign elite. However, given the scarcity of crucial specimens, especially females, and comparative skeletal series, this conclusion must remain tentative. Copyright 1999 Wiley-Liss, Inc.

  14. A paleoneurohistological study of 3,000-year-old mummified brain tissue from the mediterranean bronze age.

    Science.gov (United States)

    Prats-Muñoz, Gemma; Malgosa, Assumpció; Armentano, Nuria; Galtés, Ignasi; Esteban, Jordi; Bombi, Josep A; Tortosa, Montserrat; Fernández, Eva; Jordana, Xavier; Isidro, Albert; Fullola, Josep M; Petit, M Àngels; Guerrero, Victor M; Calvo, Manuel; Fernández, Pedro L

    2012-01-01

    Mummified nervous tissue is very rarely found in ancient remains and usually corresponds to corpses which were frozen or preserved in bogs, conditions which limit tissue autolysis and bacterial degradation. Here, we show the unusual finding of spontaneously mummified brain tissue from several individuals from the little known megalithic talaiotic culture of the island of Minorca, dating approximately 3,000 years before present and corresponding to the late Mediterranean Bronze Age. These individuals were part of an intact burial site containing 66 subjects. Intracraneal samples were carefully rehydrated with Sandison's solution. We used classical histochemical as well as 2D and 3D (scanning) electron-microscopic techniques. We provide evidence of the nervous nature of the samples as well as a detailed description of the morphological features of these ancient tissues. The intracranial material consisted of well-preserved eosinophilic reticular tissue and, although mostly absent, some exceptional pigment-containing neurons were identified. We present a detailed morphological analysis which can provide valuable information and guidelines for the interpretation of this scarce type of mummified samples and provide explanations for this surprising preservation. Copyright © 2012 S. Karger AG, Basel.

  15. New archaeomagnetic directions from Portugal and evolution of the geomagnetic field in Iberia from Late Bronze Age to Roman Times

    Science.gov (United States)

    Palencia-Ortas, A.; Osete, M. L.; Campuzano, S. A.; McIntosh, G.; Larrazabal, J.; Sastre, J.; Rodriguez-Aranda, J.

    2017-09-01

    This study presents new archaeomagnetic results from 33 combustion structures (kilns and hearths) from the archaeological sites of Castelinho, Crestelos, Olival Poço da Barca and Fonte do Milho in NE Portugal. The age of the investigated structures ranges from 1210 BC to 200 AD according to calibrated radiocarbon dating, thermoluminescence dating and archaeological constraints. Stepwise thermal and alternating field demagnetization isolate a single, stable, characteristic remanence component with very well defined directions. Rock magnetic analyses suggest low-Ti titanomagnetite/maghemite as the main magnetic carrier of the remanence. Mean directions are well grouped in most structures. The effect of thermoremanent anisotropy on mean directions has been evaluated and was found to be important. Inclination increases of between 2° and 13° after applying the anisotropy correction at specimen level. This highlights the requirement of evaluating this effect on the directions of small and flattened thin kilns and hearths. The 31 new directional data improve both the temporal and spatial distribution of the Iberian archaeomagnetic dataset from Late Bronze Age to Roman Times. Finally, a new directional palaeosecular variation curve for Iberia for the last twelve centuries BC is proposed. The curve has been computed using the bootstrap method and includes data coming from sites within 900 km of Madrid. The new palaeodirectional secular variation curve for Iberia is consistent with the Western European palaeosecular variation curve and with the prediction of regional European models.

  16. Funeral sites of the beginning of the Late Bronze age in the estuarine Trans-Kama river area

    Directory of Open Access Journals (Sweden)

    Lyganov Anton V.

    2015-06-01

    Full Text Available The paper offers results of 2014 field research of the first stage of the late Bronze Age burial grounds in the Volga-Kama region –Novo-Mordovo II and Stary Kuybyshev VI. These burial grounds are located in the area of the abrasion escarpment of Kuybyshev dam lake, in the confluence of the Volga and the Kama rivers. The first burial ground was discovered by A.H. Khalikov in 1962, the second is a recent discovery. The authors believe that the funeral rite and the inventory of these sites are very similar. All inhumations were made in shallow sub-quadrangular pits, in a crouched position on the left side. The funeral rite and the inventory combine elements of the Pokrovskiy and the Potapovskiy cultural types, which makes the authors to suggest the origins of formation of the Zaymishche type sites here. Analogies revealed in the sites of the Pokrovskiy and Potapovskiy types date existence of Novo-Mordovo II and Stary Kuybyshev VI burial grounds to the period preceding the Srubnaya cultural-historical community, and overall can fit within 19th – 18th centuries BC.

  17. A small Bronze Age mining camp: La Loma de la Tejería (Albarracín, Teruel

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    Montero Ruiz, Ignacio

    2008-06-01

    Full Text Available This paper shows the research done at Loma de la Tejería (Albarracín, Teruel where a seasonal camp site linked to a mining-metallurgical works has been discovered. Studies on materials show the use of different geological resources: copper minerals, Keuper clays with “Jacintos de Compostela” and volcanic rocks. Pottery residual analysis has documented dairy milky products and alcoholic drinks. Chronologically the site is classified amongst Chalcolithic and Early Bronze Age, on the presence of Bell Beaker pottery.

    Se presentan los datos de las excavaciones realizadas en la Loma de la Tejería (Albarracín, Teruel en la que se documenta un campamento estacional vinculado a tareas minero-metalúrgicas de pequeña escala. Los estudios realizados sobre el material indican el aprovechamiento de los recursos geológicos locales tanto de mineral de cobre, como de arcillas del Keuper con Jacintos de Compostela y rocas volcánicas. Los análisis de residuos han documentado en la cerámica productos lácteos y bebidas alcohólicas. Cronológicamente el yacimiento se encuadra en el Calcolítico y Bronce Antiguo, con presencia de cerámica campaniforme.

  18. Facile synthesis of pure monoclinic and tetragonal zirconia nanoparticles and their phase effects on the behavior of supported molybdena catalysts for methanol-selective oxidation.

    Science.gov (United States)

    Li, Weizhen; Huang, Hua; Li, Hongjia; Zhang, Wei; Liu, Haichao

    2008-08-05

    Pure monoclinic (m) and tetragonal (t) zirconia nanoparticles were readily synthesized from the reaction of inorganic zirconium salts (e.g., hydrated zirconyl nitrate) and urea in water and methanol, respectively, via a facile solvothermal method. The role of the solvents was crucial in the formation of the pure ZrO(2) phases, whereas their purity was essentially insensitive to other variables, including reaction temperature, reactant concentration, pH, and zirconium salts. Water as the solvent led to the transformation of hydrous ZrO(2) precipitates initially formed with tetragonal structures to thermodynamically more stable m-ZrO(2) via the dissolution-precipitation process, whereas methanol favored the removal of water molecules from the precursors via their reaction with urea, consequently maintaining the tetragonal structures. The obtained tetragonal samples were found to possess superior hydrothermal stability compared to those reported previously, which provides the possibility for systematically studying the effects of ZrO(2) phases on many catalytic reactions involving water as a reactant or product. Using these pure m- and t-ZrO(2) phases as supports, dispersed MoO(x) catalysts were synthesized at MoO(x) surface densities of approximately 5.0 Mo/nm(2), which is close to one monolayer of coverage. Characterization by X-ray diffraction and Raman spectroscopy confirmed that the pure ZrO(2) phases remained unchanged in the presence of the MoO(x) domains and the MoO(x) domains existed preferentially as 2D polymolybdate structures. The catalysts were subsequently examined for selective methanol oxidation as a test reaction. m-ZrO(2) support led to 2-fold greater oxidation rates than for t-ZrO(2) support, reflecting the higher intrinsic reactivity of the MoO(x) domains on m-ZrO(2). This is consistent with their higher reducibility probed by temperature-programmed reduction with H(2) (H(2) TPR). These observed effects of the ZrO(2) phases provide the basis for

  19. Corrosion of dental nickel-aluminum bronze with a minor gold content-mechanism and biological impact.

    Science.gov (United States)

    Ardlin, Berit I; Lindholm-Sethson, Britta; Dahl, Jon E

    2009-02-01

    To study corrosion and to evaluate biological effects in vitro of corrosion products of a copper-aluminum-nickel alloy with 2% gold. The alloy NPGtrade mark+2 with the nominal composition Cu:77.3; Al:7.8; Ni:4.3; Fe:3.0; Zn:2.7; Au:2.0; and Mn:1.7 was characterized. Static immersion in acidic saline, pH 2.2-2.4, was used to determine release of metallic elements in a milieu simulating the condition of plaque build-up in interproximal areas of the tooth. Corrosion and surface reactions in saline and artificial saliva were studied by electrochemical techniques including registration of open-circuit-potentials, polarization curves and impedance spectra. Extracts were made in cell culture media and acidic saline and used for MTT test for cytotoxicity and HET-CAM method for irritation. The mean amount of elements released in the acidic saline were in microg cm(-2) : Cu:632; Al:210; Ni:144; Fe:122; Zn:48; Mn:52. No protective film was formed on the surface of the alloy, as extensive corrosion was observed in both saline and artificial saliva. The corrosion rate was higher in saline than in artificial saliva. Acidic extracts of the alloy diluted up to 64 times reduced cell viability with 80% or more. The extract induced coagulation of the blood vessels of the CAM and was rated as moderate irritant solution. The nickel-aluminum bronze showed high corrosion rate caused by an inability to create a protective surface layer. High levels of toxic elements were found after static immersion testing, and the corrosion products had a distinct adverse effect on the biological activity. Copyright 2008 Wiley Periodicals, Inc.

  20. Intermediate Bronze Age in Southern Levant (4200–4000 BP – Why Did Four Cities in Transjordan Survive Urban Collapse?

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    Bieniada Michał E.

    2016-06-01

    Full Text Available The first urban culture of southern Levant collapsed and the first period of urbanisation of Canaan (Early Bronze Age I-III terminated at around 4200 yrs BP. The Canaanites abandoned their walled cities, dispersed and underwent pastoralisation. However, the urban centres of southern Canaan were not destroyed. This fact may point to responsibility of the environmental factor and makes influence influence of anthropogenic factors uncertain, along with the most popular Amorite invasion/destruction hypothesis. A tremendous climatic change occurred at that time in many regions, affecting cultures and civilisations of the Ancient Near East and resulting in abandonment of cities, migrations and great civilizational changes. In southern Levant, virtually all cities were left in ruins with a mysterious exception in Transjordan where four cities: Aroer, Ader, Khirbet Iskander and Iktanu survived and existed throughout the period. Most probably when climatic conditions in Cisjordan excluded possibility of urban life, the ones in Transjordan conditions remained unchanged or altered in a very limited scale. It is now clear that after a period with quite humid and warm climate, the precipitation greatly diminished after 4200 yrs BP in a littoral zone of eastern Mediterranean. A part of Transjordan, probably due to presence of the Dead Sea that somehow created conditions that influenced precipitation, remained a climatic niche with decent rainfall that enabled concentration of population in and around big urban centres and continuation of urban civilisation. Warming in a littoral zone changed dew point temperature preventing formations of clouds above western slopes of Judean and Samarian Hills. Moist air, prevented from condensation was transported eastwards where it could reach ascending currents appearing over the Dead Sea. Masses of air with water vapour moving upwards could form rainy clouds in Transjordan.

  1. Comparative analysis of niobium and vanadium carbide efficiency in the high energy mechanical milling of aluminum bronze alloy

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    Alexandre Nogueira Ottoboni Dias

    Full Text Available Abstract This study aims to analyze the efficiency of niobium and vanadium carbides in the high energy mechanical milling of aluminum bronze alloy. Two series of experiments were made following the same steps for both niobium carbide (NbC and vanadium carbide (VC additions: 30 g of chips were weighed and placed in a stainless steel jar with 3 % of carbide and 1 % of stearic acid for a mass/sphere relationship of 1:10. The milling was realized using a planetary ball mill for 10, 30 and 50 hours in an inert argon atmosphere at 300 rpm. Results shown in laser diffraction indicate a great reduction in the particle sizes of powders when VC is used. For 30 hours milling, D50 values ranged from 1580 µm with NbC to 182.3 µm with VC addition. The D50 values ranged from 251.5 µm with NbC to 52.26 µm with VC addition, for 50 hours milling. The scanning electron microscopy showed that in 10 hours of milling, the energy was not sufficient to achieve the shear of chips in both cases. For 30 hours, it's possible to observe particles with sizes between 100 µm and 800 µm with NbC addition while for the same milling time, with VC it's possible to see particles with different sizes, but with many shapes of fine particulates. For 50 hours milling, particles achieved the smaller sizes between 50 and 200 µm with NbC and ranging from 5 until 50 µm with VC addition.

  2. Tetragonal (K, Na)NbO3 based lead-free single crystal: Growth, full tensor properties, and their orientation dependence

    Science.gov (United States)

    Zheng, Limei; Wang, Junjun; Liu, Xuedong; Yang, Liya; Lu, Xiaoyan; Li, Yanran; Huo, Da; Lü, Weiming; Yang, Bin; Cao, Wenwu

    2017-10-01

    A Li and Ta modified (K, Na)NbO3 lead-free single crystal with a large size (13 × 10 × 20 mm3) has been grown by using the top-seeded solution growth method. The large size allows us to carry out an extensive study on this tetragonal crystal. We have measured a complete set of elastic, dielectric, and piezoelectric constants for the [001]C poled crystal with the single domain state. The crystal exhibits high shear piezoelectricity with d15 = 518 pC/N and k15 = 0.733, showing excellent potential in shear electro-sonic energy transformation devices. It is found that the high shear piezoelectricity originates from the vicinity of orthorhombic-tetragonal phase transition, which favors polarization rotation greatly. The orientation dependence of longitudinal dielectric, piezoelectric, and elastic constants and electromechanical coupling factor in the 3-dimentional space were calculated based on the single domain dataset. We believe that this work is of great importance for both fundamental studies and device designs for lead-free materials.

  3. Electric field-induced phase transitions and composition-driven nanodomains in rhombohedral-tetragonal potassium-sodium niobate-based ceramics

    KAUST Repository

    Lv, Xiang

    2017-08-07

    The mechanisms behind the high piezoelectricity of (K,Na)NbO3-based lead-free ceramics were investigated, including electric field-induced phase transitions and composition-driven nanodomains. The construction of a rhombohedral-tetragonal (R-T) phase boundary, confirmed using several advanced techniques, allowed a large piezoelectric constant (d33) of 450 ± 5 pC/N to be obtained in (1-x)K0.4Na0.6Nb0.945Sb0.055O3-xBi0.5Na0.5(Hf1-ySny)O3 (0 ≤ x ≤ 0.06 and 0 ≤ y ≤ 0.5) ceramics possessing an ultralow ΔUT-R of 7.4 meV. More importantly, the existence of an intermediate phase, i.e., the electric-induced phase (EIP), bridging the rhombohedral R [Ps//(111)] and tetragonal T [Ps//(001)] phases during the polarization rotation was demonstrated. Striped nanodomains (∼40 nm) that easily responded to external stimulation were also observed in the ceramics with an R-T phase. Thus, the enhanced piezoelectric properties originated from EIP and the striped nanodomains.

  4. Tetragonal ZrO2 phase stabilization in coating layers prepared on Zr-2.5%Nb alloy during plasma electrolytic oxidation in sodium aluminate electrolytes

    Science.gov (United States)

    Malinovschi, V.; Marin, A.; Negrea, D.; Andrei, V.; Coaca, E.

    2017-09-01

    Layers containing polycrystalline zirconia and amorphous aluminum oxide were obtained by plasma electrolytic oxidation (PEO) of Zr-2.5%Nb alloy in aqueous electrolyte solutions comprising NaAlO2 (pH  =  13.0), NaAlO2 and NaOH (pH  =  13.2), respectively. The PEO coatings were analyzed by x-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and potentiodynamic polarization tests. The deposited coating layers contain mainly tetragonal ZrO2 polycrystalline phase and amorphous aluminum oxide (Al2O3) phase. They have thicknesses between 9.0 and 53.0 µm and are uneven, heterogeneous and porous. Zirconia tetragonal phase stabilization by the aluminum oxide matrix was achieved through the ‘constraint’ mechanism. The corrosion current density values for the PEO layers are lower by 1-2 orders of magnitude than those of the untreated Zr-2.5%Nb alloy.

  5. Optical spectroscopy study of the collapsed tetragonal phase of CaFe2(As0.935P0.065)2 single crystals

    Science.gov (United States)

    Wang, X. B.; Wang, H. P.; Dong, T.; Chen, R. Y.; Wang, N. L.

    2014-10-01

    We present an optical spectroscopy study on P-doped CaFe2As2 which experiences a structural phase transition from tetragonal to collapsed tetragonal (cT) phase near 75 K. The measurement reveals a sudden reduction of low-frequency spectral weight and the emergence of a feature near 3200 cm -1 (0.4 eV) in optical conductivity across the transition, indicating an abrupt reconstruction of band structure. The appearance of the feature is related to the interband transition arising from the sinking of hole bands near the Γ point below Fermi level in the cT phase, as expected from the density function theory calculations in combination with the dynamical mean field theory. However, the reduction of Drude spectral weight is at variance with those calculations. The measurement also indicates an absence of the abnormal spectral weight transfer at high energy (near 0.5-0.7 eV) in the cT phase, suggesting a suppression of the electron correlation effect.

  6. Efecto de la nitruración en la degradación hidrotérmica de circona tetragonal policristalina estabilizada con Y2O3

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    Anglada, M.

    2004-02-01

    Full Text Available The effect of nitridation at 1650 ºC during 2 hours on hydrothermal aging of Y-TZP stabilized with 2.5 % moles of yttria has been studied. It has been shown that the superficial layer of nitrided samples was resistant to t→m phase transformation in water at 100 ºC during the investigated time period (850 hours. Conversely, the non-nitrided material transformed at the surface but no significant reduction in biaxial strength was observed. However, the biaxial strength of nitrided samples diminishes with hydrothermal aging time, which is thought to be due to the presence of an important amount of monoclinic phase inside the sample which is due to the high transformability of tetragonal grains. It appears that water does not play any important role in degradation of nitrided samples. The observations has been associated to changes in crystalline structure of a surface layer and to the high transformability of the tetragonal phase to monoclinic one inside the nitrided samples.Se ha estudiado el efecto de la nitruración a 1650 ºC durante 2 horas en la degradación hidrotérmica de una cerámica policristalina (YTZP estabilizada con 2.5% molar de itria. Se ha observado que la microestructura superficial de la cerámica nitrurada es resistente a la transformación de fase t→m en presencia de agua a 100 ºC durante el período de tiempo investigado (850 horas, mientras que el material de partida se transforma en la superficie, pero no sufre ninguna reducción significativa en la resistencia. Sin embargo, en las muestras nitruradas se observa una disminución de la resistencia a flexión biaxial con el tiempo de ataque hidrotérmico, la cual se atribuye a la presencia de una cantidad importante de fase monoclínica en el interior de la muestra. Es decir, los granos situados en esta zona son más transformables en las probetas nitruradas, sin que el agua desempeñe aparentemente ningún papel en la degradación de la resistencia de estas muestras

  7. Comparative study on cubic and tetragonal CexZr1-xO2 supported MoO3-catalysts for sulfur-resistant methanation

    Science.gov (United States)

    Liu, Zhaopeng; Xu, Yan; Cheng, Jiaming; Wang, Weihan; Wang, Baowei; Li, Zhenhua; Ma, Xinbin

    2018-03-01

    In this paper, two kinds of CexZr1-xO2 solid solution carriers with different Ce/Zr ratio were prepared by one-step co-precipitation method: the cubic Ce0.8Zr0.2O2 and the tetragonal Ce0.2Zr0.8O2 support. The MoO3/Ce0.8Zr0.2O2 and MoO3/Ce0.2Zr0.8O2 catalysts were prepared by incipient wetness impregnation method for comparative study on sulfur-resistant methanation reaction. The N2 adsorption/desorption, X-ray diffraction (XRD), Raman spectroscopy (RS), X-ray photoelectron (XPS), transmission electron microscopy (TEM), temperature-programmed reduction by hydrogen (H2-TPR) were undertaken to characterize the physico-chemical properties of the samples. The results indicated that the prepared MoO3/CexZr1-xO2 catalysts have a mesoporous structure with high surface area and uniform pore size distribution, achieving good MoO3 dispersion on CexZr1-xO2 supports. As for the catalytic performance of sulfur-resistant methanation, the cubic MoO3/Ce0.8Zr0.2O2 exhibited better than the tetragonal MoO3/Ce0.2Zr0.8O2 catalyst at reaction temperature 400 °C and 450 °C. CO conversion on the cubic MoO3/Ce0.8Zr0.2O2 catalyst was 50.1% at 400 °C and 75.5% at 450 °C, which is respectively 7% and 20% higher than that on the tetragonal MoO3/Ce0.2Zr0.8O2 catalyst. These were mainly attributed to higher content of active MoS2 on the surface of catalyst, the enhanced oxygen mobility, increased Mo-species dispersion as well as the excellent reducibility resulted from the increased amount of the reducible Ce3+ on the cubic MoO3/Ce0.8Zr0.2O2 catalyst.

  8. The sun, moon and stars of the southern Levant at Gezer and Megiddo: Cultural astronomy in Chalcolithic/Early and Middle Bronze Ages

    Science.gov (United States)

    Gardner, Sara Lee

    Astronomical images are found on monumental structures and decorative art, and metaphorically in seasonal myths, and are documented by calendars. In Israel and the southern Levant, images of the sun, the moon, and the stars were common decorating motifs. They were found on walls, pottery, and seals and date to as early as the Chalcolithic period; for example, the wall painting of a star at Teleilat Ghassul (North 1961). This dissertation establishes that the people of the Levant were aware of the apparent movement of the sun, and this will be discussed in Chapter 4. They began recording through representation drawings, astronomical phenomena no later than the Chalcolithic/Early Bronze Age and continued to do so late into the Middle Bronze Age. The argument moves beyond the simple use of symbols to the use of images to represent constellations, with the focus on the constellation Leo in Chapter 5. Furthermore, the use of astronomy as a power and political tool is also suggested in Chapter 6. Nonetheless, the primary purpose that is addressed here is the tendency in Syro-Palestinian archaeology has been to attribute technological evidence found in the northern and southern Levant as diffused from Egypt or Assyria, particularly astronomy. This dissertation firmly establishes that astronomy was used in the southern Levant before any significant contact with the civilizations of Egypt or Assyria.

  9. Robust date for the Bronze Age Avellino eruption (Somma-Vesuvius): 3945 ± 10 calBP (1995 ± 10 calBC)

    Science.gov (United States)

    Sevink, Jan; van Bergen, Manfred J.; van der Plicht, Johannes; Feiken, Hendrik; Anastasia, Carmela; Huizinga, Annika

    2011-05-01

    We found Bronze Age lake sediments from the Agro Pontino graben (Central Italy) to contain a thin (2-3 cm) continuous tephra layer composed of lithics, crystals and minor volcanic glass. Tephrochronological and compositional constraints strongly suggest that this layer represents the Avellino pumice eruption, which has also been identified in Central Italian lake cores. Its provenance is corroborated by electron-microprobe analyses performed on juvenile pumice grains, showing that the tephra layer is probably the distal equivalent of the EU2 event of the Avellino eruption. We used multiple 14C age estimations of two lacustrine sequences with intercalated tephra layer, from the western border zone (Migliara 44.5) and the centre of the former lake (Campo Inferiore), for in tandem dating of this eruption, employing the OxCal code, which yielded a robust age of 3945 ± 10 calBP (1995 ± 10 calBC). To date, this is the only study providing both a terminus post and terminus ante quem of this precision, also demonstrating the advantage of dating distal tephra layers in a clear stratigraphic context over proximal deposits in sequences with major stratigraphic hiatuses. Our new results underscore the importance of the Avellino tephra layer as a precise time marker for studies on the Early Bronze Age of Central Italy.

  10. Establishing the archaeo-metallurgic ornamentation process of an axe from the bronze age by OM, SEM-EDX, and micro-FTIR.

    Science.gov (United States)

    Sandu, Ioan Gabriel; Tencariu, Felix-Adrian; Vornicu, Diana-Măriuca; Sandu, Andrei Victor; Vornicu, Andreea; Vasilache, Viorica; Sandu, Ion

    2014-11-01

    Our article presents the results of the analyses we performed by corroborating the Optical Microscopy, Scanning Electron Microscopy, Energy Dispersive Xray Analysis and micro Fourier Transformed InfraRed Analysis techniques to identify the archaeo-metallurgic casting and ornamentation procedure of a decorated disk-butted axe, which was discovered recently east of the Carpathian mountains, in the Moldavian Plateau. There are few known axes of that type found (A1, according to the usual typologies), as they are specific to the Middle Bronze Age period west of the Carpathians-the Wietenberg, Suciu de Sus, and Otomani-Füzesabony cultures. The experimental data on the item under study revealed the fact that after casting it in molds made from porous silicone-based stone, the object was coated with a thin layer, by immersing it in a lightly fusible tin alloy, whose main alloy component was copper and arsenic and iron as secondary components. After refining the shiny white layer, they applied a beautiful decoration pattern made by incision and engraving. This battle axe was an indication of higher status, such items usually being owned by community leaders. This important fact proves that the ancient metallurgic craftsmen were able to elaborate and manufacture various alloys from which they made beautiful objects and it also offers a new insight into the social and symbolic function of certain antique bronze items. © 2014 Wiley Periodicals, Inc.

  11. Textile production in the Bronze Age: an assemblage of splindes or bobbins of yarn from the site of Terlinques (Villena, Alicante

    Directory of Open Access Journals (Sweden)

    Jover Maestre, Francisco Javier

    2001-06-01

    Full Text Available The archeological field work on the Bronze Age site of Terlinques (Villena, Alicante has given an exceptional sample of spindles or bobbins of rush fibre of yarn in a room destroyed by a violent fire. A meticulous study of these special objects and their process of analysis and restoration yields new perspectives on knowledge in first stages of textile production during Bronze Age in Eastern Spain.

    Los trabajos arqueológicos que se llevan a cabo en el yacimiento de la Edad del Bronce de Terlinques (Villena, Alicante han proporcionado un excepcional conjunto de husos o bobinas de hilo de junco. Éstos se hallaban almacenados en el interior de una habitación destruida por un violento incendio. El detenido estudio de estos singulares objetos y su proceso de análisis y restauración nos permite aproximamos, desde nuevas perspectivas, al conocimiento de la producción textil en las etapas iniciales de la Edad del Bronce en el Levante de la Península Ibérica.

  12. Protocol of thermal treatments for the recovery of tetragonal phase in infrastructures of dental prostheses base of ZrO{sub 2} (3-Y{sub 2}O{sub 3}) mills in CAD / CAM systems or panthories; Protocolo de tratamentos termicos visando recuperacao da fase tetragonal em infraestruturas de proteses dentarias a base de ZrO{sub 2}(3-Y{sub 2}O{sub 3}) fresadas em sistemas CAD/CAM ou pantografos

    Energy Technology Data Exchange (ETDEWEB)

    Simba, B.G.; Ferreira, B.; Santos, C. [Universidade de Sao Paulo (EEL/USP), Lorena, SP (Brazil). Escola de Engenharia; Costa, L. [Centro Universitario de Volta Redonda (MeMAT/UNIFOA), RJ (Brazil). Pro-Reitoria de Pesquisa e Extensao; Sa, L.F.C. de, E-mail: brgalvao@yahoo.com.br [PROTMAT Materiais Avancados, Volta Redonda, RJ (Brazil)

    2011-07-01

    ZrO{sub 2}(3%Y{sub 2}O{sub 3}) bioceramics are used as dental materials mainly as prosthesis components, because present high mechanical properties and translucence. The use of CAD/CAM machining technique needs final grinding which promotes tetragonal monoclinic transformation reducing the reliability of this ceramic. In this work, ZrO{sub 2}(3%Y{sub 2}O{sub 3}) ceramics were sintered at 1450-0h, 1530-2h or 1600-4h and characterized. Different heat-treatment (400-1200 deg C) are proposed aiming the recuperation of the tetragonal crystalline phase. (author)

  13. The Metallurgy of the Sicilian Final Bronze Age/Early Iron Age necropolis of Madonna del Piano (Catania, Sicily

    Directory of Open Access Journals (Sweden)

    Giumlia-Mair, Alessandra

    2010-12-01

    Full Text Available This paper presents the analysis results of the copper- based finds, from the important Sicilian necropolis of Madonna del Piano, near Grammichele (Catania, dated between the local Final Bronze Age 2 and the Early Iron Age IA. 122 copper-based finds from the 273 graves (1970-71 of the large cemetery have been analysed. The sampled objects belong to different classes, there are for instance weapons of offence and defence, such as swords and greaves, small decorative objects for personal use, such as rings, fibulae, belt hooks, belt decorations, and small tools, such as the knives used by women, reels, needles and razors, but also small functional parts, such as rivets and nails, repairs and even a kind of musical instrument, such as the tintinnabula. The methods employed were AAS and SEM, where possible, and XRF in all cases. The aim of the research was that of evaluating the skill of the local artisans, of determining the most common copper-based alloys in use in Sicily in this period and comparing the data with the analysis results of contemporary groups of finds from other areas of the Italian peninsula and from other European regions.

    El artículo presenta el resultado de los análisis realizados a los metales de base cobre de la importante necrópolis siciliana de Madonna del Piano, próxima a Grammichele (Catania, fechada entre el Bronce Final 2 y la Primera Edad del Hierro IA. Se han estudiado un total de 122 objetos de base cobre procedentes de 273 tumbas excavadas entre 1970 y 1971. Los objetos muestreados pertenecen a diferentes tipos, armas ofensivas y defensivas tales como espadas y grebas, pequeños objetos de uso personal como anillos, fíbulas, broches de cinturón y pequeñas herramientas como cuchillos usados por las mujeres, carretes, agujas, navajas, pero también elementos funcionales como remaches, clavos y un tipo de instrumento como el tintinábulo. Los métodos de análisis utilizados fueron AAS y SEM, cuando fue

  14. The rôle of the Kokino megalith in the life of the Bronze age agricultural community

    Science.gov (United States)

    Cenev, Gjore

    2011-06-01

    In 2002 in the region of North-East Macedonia a site was discovered, for which archaeoastronomical analyses have shown that it encompasses all elements of an ancient observatory dated 2000 BCE. In line with the analysis the existence of a central position, from where Sunrises and rises of Full Moon were observed, was confirmed, as well as that in the rocks on the east horizon a markers were crafted marking the places of the rise of the Sun and Moon in exactly determined days. From this central position, total 9 markers can be seen on the east horizon, 3 of which used to mark the places of the Sunrise in the course of the year, and remaining 6 marked the places of Full Moon rise. By continuous monitoring of the periodicity of the Full Moon rise, ancient sky observers could develop 19 years periodic lunar calendar. In addition, on the site there is a special observation place related to the cycles of solar and lunar eclipse. Only from there and toward the east horizon 4 markers can be seen, which were used for marking the positions of the Full Moon rise on the day of the beginning of the new periodic cycle of eclipse of 54 years and 34 days. The most outstanding content on the territory of the observatory are 4 stone seats called thrones. Also, on the east horizon there is one specially crafted marker that had ritual purpose. Archaeoastronomical analysis has shown that on the day when the harvest ends, rise of Sun could be seen exactly trough the aperture of this marker, enlightening by beam only one of the thrones where most probably a community headman was sitting. That was a ritual joining of the God Sun with the community headman and renewal of his energy as a guarantee for rich harvest in the coming year. This is just a fragment of information that Megalithic Observatory Kokino has to offer, linked with the culture and cosmological presentations of people of the early agricultural community in the Bronze Age.

  15. Core/Shell Face-Centered Tetragonal FePd/Pd Nanoparticles as an Efficient Non-Pt Catalyst for the Oxygen Reduction Reaction.

    Science.gov (United States)

    Jiang, Guangming; Zhu, Huiyuan; Zhang, Xu; Shen, Bo; Wu, Liheng; Zhang, Sen; Lu, Gang; Wu, Zhongbiao; Sun, Shouheng

    2015-11-24

    We report the synthesis of core/shell face-centered tetragonal (fct)-FePd/Pd nanoparticles (NPs) via reductive annealing of core/shell Pd/Fe3O4 NPs followed by temperature-controlled Fe etching in acetic acid. Among three different kinds of core/shell FePd/Pd NPs studied (FePd core at ∼8 nm and Pd shell at 0.27, 0.65, or 0.81 nm), the fct-FePd/Pd-0.65 NPs are the most efficient catalyst for the oxygen reduction reaction (ORR) in 0.1 M HClO4 with Pt-like activity and durability. This enhanced ORR catalysis arises from the desired Pd lattice compression in the 0.65 nm Pd shell induced by the fct-FePd core. Our study offers a general approach to enhance Pd catalysis in acid for ORR.

  16. Tetragonal zinc-blende MnGa ultra-thin films with high magnetization directly grown on epi-ready GaAs(111) substrates

    Science.gov (United States)

    Arins, A. W.; Jurca, H. F.; Zarpellon, J.; Varalda, J.; Graff, I. L.; de Oliveira, A. J. A.; Schreiner, W. H.; Mosca, D. H.

    2013-03-01

    We report on high quality MnGa epilayers directly grown on GaAs(111)-(1 × 1) reconstructed surface. MnGa layers are characterized by the stacking of (111) planes of tetragonal zinc-blende structure, which are rotated by 11° with respect to the underlying (111) planes of the GaAs lattice. These ultra-thin MnGa epilayers with lattice parameters a = 0.55 nm and c = 0.61 nm are stabilized for thickness between 5 and 20 nm with a net magnetic moment of 3.2 μB per Mn atom. These epilayers are potentially suited for semiconductor spintronics applications due to the reversal of its magnetization in relatively low magnetic fields.

  17. A structural study of tetragonal (Ca sub 1-x Ba sub x La) (Cu sub 3-y Pt sub y )O sub 7-z ''single'' crystals. [Ca-Ba-La-Cu-Pt-O

    Energy Technology Data Exchange (ETDEWEB)

    Amador-Elizondo, U.; Senaris, M.A.; Moran, E.; Alario-Franco, M.A. (Dept. Q Inorganica, Univ. Complutense, Madrid (Spain)); Vegas, A.; Martinez-Ripoll, M. (Inst. ' Rocasolano' , C.S.I.C., Madrid (Spain)); Ibanez, J. (C.E.N.I.M., C.S.I.C., Madrid (Spain))

    1990-10-15

    A structural study in ''single'' crystals of the title material indicates that in addition to the average tetragonal structure (a x a x 3a) different phenomena and several degrees of order are observed, probably related to a very complex cationic distribution among the structural sites. (orig.).

  18. Origin of the stabilization of the metastable tetragonal high-pressure phase in SrCuO{sub 2} thin films grown on SrTiO{sub 3} substrates by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mihailescu, C.N. [Nanotechnology Research Center and Department of Mechanical and Manufacturing Engineering, University of Cyprus, 75 Kallipoleos Av., PO Box 20537, 1678 Nicosia (Cyprus); National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor St., PO Box MG-36, 077125 Magurele (Romania); Pasuk, I. [National Institute of Materials Physics, RO-077125 Magurele (Romania); Straticiuc, M.; Nita, C.R.; Pantelica, D. [Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH), 30 Reactorului Street, P.O. Box MG-6, RO-077125 Magurele (Romania); Giapintzakis, J., E-mail: giapintz@ucy.ac.cy [Nanotechnology Research Center and Department of Mechanical and Manufacturing Engineering, University of Cyprus, 75 Kallipoleos Av., PO Box 20537, 1678 Nicosia (Cyprus)

    2014-11-30

    Highlights: • By tuning the substrate temperature one can obtain SrCuO{sub 2} films that exhibit both stable (orthorhombic) and metastable (tetragonal) phases in pure form as well as films composed of a mixture of tetragonal and orthorhombic phases. • SrCuO{sub 2} films exhibit a stoichiometry variation across the temperature range of the structural transformation. • The non-equilibrium nature of the growth process is the origin of the stabilization of the tetragonal (hp I) phase in SrCuO{sub 2} thin films grown on SrTiO{sub 3} substrates at low substrate temperatures. - Abstract: In this work we have systematically investigated the evolution of structure and stoichiometry in SrCuO{sub 2} films grown on TiO{sub 2}-terminated SrTiO{sub 3} substrates as a function of the substrate temperature. Depending on the growth temperature SrCuO{sub 2}/SrTiO{sub 3} films can exhibit either a pure tetragonal high-pressure phase, or a pure orthorhombic low-pressure phase, or a mixed phase. Our results indicate that at low substrate temperatures the non-equilibrium state of the growth process is responsible for the stabilization of the metastable tetragonal high-pressure structure in SrCuO{sub 2} thin films grown on ( 0 0 1) SrTiO{sub 3} substrates, whose lattice matches the metastable structure. In addition, at higher substrate temperatures thermodynamics become dominant over other factors and the SrCuO{sub 2} thin films are stabilized in the thermodynamically stable orthorhombic phase.

  19. Evolution of coherent collective modes through consecutive charge-density-wave transitions in the (PO2)4(WO3)12 monophosphate tungsten bronze

    Science.gov (United States)

    Stojchevska, L.; Borovšak, M.; Foury-Leylekian, P.; Pouget, J.-P.; Mertelj, T.; Mihailovic, D.

    2017-07-01

    All-optical femtosecond relaxation dynamics in a single crystal of monophosphate tungsten bronze (PO2)4(WO3)2m with alternate stacking m =6 of WO3 layers was studied through the three consequent charge-density-wave (CDW) transitions. Several transient coherent collective modes associated with the different CDW transitions were observed and analyzed in the framework of the time-dependent Ginzburg-Landau theory. Remarkably, the interference of the modes leads to an apparent rectification effect in the transient reflectivity response. A saturation of the coherent-mode amplitudes with increasing pump fluence well below the CDWs destruction threshold fluence indicates a decoupling of the electronic and lattice parts of the order parameter on the femtosecond timescale.

  20. The hydrogeological and paleoclimatic factors in the Bronze Age Motillas Culture of La Mancha (Spain): the first hydraulic culture in Europe

    Science.gov (United States)

    Benítez de Lugo Enrich, Luis; Mejías, Miguel

    2017-11-01

    Recent studies indicate that the motillas (Chalcolithic and Bronze Age settlements in La Mancha, Spain) could have constituted the most ancient groundwater collection system at regional scale in Europe. This paper presents the first hydrogeoarchaeological study at the regional level in La Mancha. The research includes borehole drilling and hydrogeological analysis of the territory on which the motillas are settled. The resulting data confirm a relationship between the geological substrate and the spatial distribution of the motillas, sited where groundwater was accessible by means of prehistoric technology. The motillas were built during the climatic event known as 4.2 ka cal BP, in a time of environmental stress after a period of severe and prolonged drought. In these environmental conditions, the construction of these wells was a successful solution that lived on for nearly a millennium and played a major part in the processes of change towards a more complex, hierarchical society.

  1. The hydrogeological and paleoclimatic factors in the Bronze Age Motillas Culture of La Mancha (Spain): the first hydraulic culture in Europe

    Science.gov (United States)

    Benítez de Lugo Enrich, Luis; Mejías, Miguel

    2017-06-01

    Recent studies indicate that the motillas (Chalcolithic and Bronze Age settlements in La Mancha, Spain) could have constituted the most ancient groundwater collection system at regional scale in Europe. This paper presents the first hydrogeoarchaeological study at the regional level in La Mancha. The research includes borehole drilling and hydrogeological analysis of the territory on which the motillas are settled. The resulting data confirm a relationship between the geological substrate and the spatial distribution of the motillas, sited where groundwater was accessible by means of prehistoric technology. The motillas were built during the climatic event known as 4.2 ka caluc( BP), in a time of environmental stress after a period of severe and prolonged drought. In these environmental conditions, the construction of these wells was a successful solution that lived on for nearly a millennium and played a major part in the processes of change towards a more complex, hierarchical society.

  2. Paleoecological crisis in the steppes of the Lower Volga region in the Middle of the Bronze Age (III-II centuries BC)

    Science.gov (United States)

    Demkina, T. S.; Borisov, A. V.; Demkin, V. A.; Khomutova, T. E.; Kuznetsova, T. V.; El'tsov, M. V.; Udal'tsov, S. N.

    2017-07-01

    Diagnostic features of a catastrophic aridization of climate, desertification, and paleoecological crisis in steppes of the Lower Volga region have been identified on the basis of data on the morphological, chemical, and microbiological properties of paleosols under archeological monuments (burial mounds) of the Middle Bronze Age. These processes resulted in a certain convergence of the soil cover with transformation of zonal chestnut (Kastanozems) paleosols and paleosolonetzes (Solonetz Humic) into specific chestnut-like eroded saline calcareous paleosols analogous to the modern brown desert-steppe soils (Calcisols Haplic) that predominated in this region 4300-3800 years ago.1 In the second millennium BC, humidization of the climate led to the divergence of the soil cover with secondary formation of the complexes of chestnut soils and solonetzes. This paleoecological crisis had a significant effect on the economy of the tribes in the Late Catacomb and Post-Catacomb time stipulating their higher mobility and transition to the nomadic cattle breeding.

  3. Surface mechanical property and residual stress of peened nickel-aluminum bronze determined by in-situ X-ray diffraction

    Science.gov (United States)

    Wang, Chengxi; Jiang, Chuanhai; Zhao, Yuantao; Chen, Ming; Ji, Vincent

    2017-10-01

    As one of the most important surface strengthening method, shot peening is widely used to improve the fatigue and stress corrosion crack resistance of components by introducing the refined microstructure and compressive residual stress in the surface layer. However, the mechanical properties of this thin layer are different from the base metal and are difficult to be characterized by conventional techniques. In this work, a micro uniaxial tensile tester equipped with in-situ X-ray stress analyzer was employed to make it achievable on a nickel-aluminum bronze with shot peening treatment. According to the equivalent stress-strain relationship based on Von Mises stress criterion, the Young's modulus and yield strength of the peened layer were calculated. The results showed that the Young's modulus was the same as the bulk material, and the yield strength corresponding to the permanent plastic strain of 0.2% was increased by 21% after SP. But the fractographic analysis showed that the fracture feature of the surface layer was likely to transform from the dimple to the cleavage, indicating the improved strength might be attained at the expense of ductility. The monotonic and cyclic loading were also performed via the same combined set-up. In addition, the specific relaxation behavior of compressive residual stress was quantified by linear logarithm relationship between residual stress and cycle numbers. It was found that the compressive residual stress mainly relaxed in the first few cycles, and then reached steady state with further cycles. The relaxation rate and the stable value were chiefly depended on the stress amplitude and number of cycles. The retained residual stress kept in compressive under all given applied stress levels, suggesting that the shot peening could introduce a more stable surface layer of compressive residual stress other than the elevated strength of nickel-aluminum bronze alloy.

  4. Micro-chemical and micro-structural investigation of archaeological bronze weapons from the Ayanis fortress (lake Van, Eastern Anatolia, Turkey)

    Science.gov (United States)

    Faraldi, F.; Çilingirǒglu, A.; Angelini, E.; Riccucci, C.; De Caro, T.; Batmaz, A.; Mezzi, A.; Caschera, D.; Cortese, B.

    2013-12-01

    Bronze weapons (VII cen BC) found during the archaeological excavation of the Ayanis fortress (lake Van, eastern Anatolia, Turkey) are investigated in order to determine their chemical composition and metallurgical features as well as to identify the micro-chemical and micro-structural nature of the corrosion products grown during long-term burial. Small fragments were sampled from the artefacts and analysed by means of the combined use of optical microscopy (OM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The results show that the bronze artefacts have been manufactured by using alloys with a controlled and refined chemical composition demonstrating the high level metallurgical competence and skill of the Urartian craftsmen and artists. Furthermore, the micro-structural and metallurgical investigations evidence the presence of equiaxed grains in the matrix, indicating that the artefact were produced by repeated cycles of mechanical shaping and thermal annealing treatments to restore the alloy ductility. From the degradation point of view, the results show the structures and the chemical composition of the stratified corrosion layers (i.e. the patina) where the copper or tin depletion phenomenon is commonly observed with the surface enrichment of some elements coming from the burial soil, mainly Cl, which is related to the high concentration of chlorides in the Ayanis soil. The results reveal also that another source of degradation is the inter-granular corrosion phenomenon likely increased by the metallurgical features of the alloys caused by the high temperature manufacturing process that induces crystallisation and segregation phenomena along the grain boundaries.

  5. Dental occlusion analysis in the Mesolithic-Neolithic Age, Bronze Age, and Roman to Medieval times in Serbia: Tooth size comparison in skeletal samples.

    Science.gov (United States)

    Pajević, Tina; Glišić, Branislav

    2017-05-01

    Anthropological studies have reported that tooth size decreases in the context of diet changes. Some investigations have found a reverse trend in tooth size from the prehistoric to the modern times. The aims of this study were to analyze tooth size in skeletal samples from Mesolithic-Neolithic Age, Bronze Age, and Roman to Medieval times to determine sex differences and establish a temporal trend in tooth size in the aforementioned periods. Well-preserved permanent teeth were included in the investigation. The mesiodistal (MD) diameter of all teeth and buccolingual (BL) diameter of the molars were measured. Effects of sex and site were tested by one-way ANOVA, and the combined effect of these factors was analyzed by UNIANOVA. Sexual dimorphism was present in the BL diameters of all molars and MD diameters of the upper first and the lower third molar. The lower canine was the most dimorphic tooth in the anterior region. The MD diameter of most teeth showed no significant difference between the groups, (sample from: Mesolithic-Neolithic Age-group 1; Bronze Age-group 2; Roman times-group 3; Medieval times-group 4), whereas the BL diameters of the upper second and the lower first molar were the largest in the first group. Multiple comparisons revealed a decrease in the BL diameter of the upper second and the lower first molar from the first to the later groups. Lower canine MD diameter exhibited an increase in the fourth group compared to the second group. On the basis of the MD diameter, a temporal trend could not be observed for most of the teeth. The lower canine exhibited an increase in the MD diameter from the prehistoric to the Medieval times. Changes of BL diameter were more homogeneous, suggesting that the temporal trend of molar size decreased from the Mesolithic-Neolithic to Medieval times in Serbia. Copyright © 2017. Published by Elsevier Ltd.

  6. Suppression of magnetism and development of superconductivity within the collapsed tetragonal phase of Ca0.67Sr0.33Fe2As2 under pressure

    Science.gov (United States)

    Jeffries, J. R.; Butch, N. P.; Kirshenbaum, K.; Saha, S. R.; Samudrala, G.; Weir, S. T.; Vohra, Y. K.; Paglione, J.

    2012-05-01

    Structural and electronic characterizations of (Ca0.67Sr0.33)Fe2As2 have been performed as a function of pressure up to 12 GPa using conventional and designer diamond anvil cells. The compound (Ca0.67Sr0.33)Fe2As2 behaves intermediately between its end members, displaying a suppression of magnetism and the onset of superconductivity. Like other members of the AFe2As2 family, (Ca0.67Sr0.33)Fe2As2 undergoes a pressure-induced isostructural volume collapse, which we associate with the development of As-As bonding across the mirror plane of the structure. This collapsed tetragonal phase abruptly cuts off the magnetic state and supports superconductivity with a maximum Tc=22.2K. The maximum Tc of the superconducting phase is not strongly correlated with any structural parameter, but its proximity to the abrupt suppression of magnetism as well as the volume-collapse transition suggests that magnetic interactions and structural inhomogeneity may play a role in its development.

  7. Measurement of structural changes in tetragonal PZT ceramics under static and cyclic electric fields using a laboratory X-ray diffractometer.

    Science.gov (United States)

    Pramanick, Abhijit; Jones, Jacob L

    2009-08-01

    In situ structural characterization techniques that are capable of characterizing piezoelectric ceramics under different electrical loading conditions are important to understand the behavior of materials during their use. In this work, we report the use of a laboratory X-ray diffractometer for the measurement of various structural changes in tetragonal La-doped lead zirconate titanate (PZT) ceramics under the application of static and cyclic electric fields. The changes in the volume fractions of the 90 degrees domains parallel to the electric field direction are calculated from the intensities of the {002} diffraction peaks. In addition, the components of lattice strains are monitored from the changes in the (111) crystallographic planes. It is observed that, under the application of static electric fields, both 90 degrees domain switching and the 111 lattice strains showed similarity with the macroscopic strain-electric field hystersis loop. To measure the structural changes under cyclic electric fields, a time-resolved X-ray diffraction technique was used. Under application of a square-wave electric field of amplitude +/-650 V/mm and frequency 0.3 Hz, a change of approximately 5% in the volume fraction of the 90 degrees domains and approximately 0.07% strain of the 111 lattice planes are observed. Both the amount of 90 degrees domain switching and the 111 lattice strains are observed to increase with an increase in the amplitude of the cyclic electric field. The implications of the measured structural changes for the macroscopic piezoelectric properties of ceramics are discussed.

  8. [Effect of Al₂O₃ sandblasting on the bond strength between 3mol% yttrium-stabilized tetragonal zirconium polycrystal zirconia framework and veneering porcelain].

    Science.gov (United States)

    Qiang, Zeng; Ning, Li; Yanan, Zhou; Jiazhen, Yan; Wenbo, Liu

    2015-12-01

    The effect of sandblasting on the bond strength between 3mol% yttrium-stabilized tetragonal zirconium polycrystal (3Y-TZP) zirconia framework and veneering porcelain was evaluated. A total of 21 specimens [(25 ± 1) mm x (3 ± 0.1) mmx (0.5 ± 0.05) mm] were prepared according to ISO 9693. The specimens were then randomly divided into 3 groups. Sandblasting was performed on 2 meshes of Al₂O₃ particles: group A with mesh 110 and group B with mesh 80. Group C, which was not sandblasted, was the control group. The surface roughness of the zirconia framework, as well as the bond strength between 3Y-TZP zirconia framework and veneering porcelain, was measured. The interface microstructure was observed by scanning electron microscope (SEM), and elemental distribution was detected by energy dispersive spectroscopy (EDS). Surface roughness values were (1.272 ± 0.149) μm for group A, (0.622 ± 0.113) μm for group B, and (0.221 ± 0.065) μm for group C. Statistical significance were found among groups (P 0.05). Interface adhesion failure was the primary performance. SEM images showed the close interface bonding, and EDS showed that the interface had no obvious element penetration. Al₂O₃ sandblasting can slightly enhance the bond strength between zirconia framework and veneering porcelain.

  9. The electronic properties and lattice dynamics of (Na{sub 0.5}Bi{sub 0.5})TiO{sub 3}: From cubic to tetragonal and rhombohedral phases

    Energy Technology Data Exchange (ETDEWEB)

    Lü, Hongfeng [Department of Applied Physics, College of Science, China Agricultural University, Beijing 100083 (China); Wang, Shanying [Department of Physics, Tsinghua University, Beijing 100084 (China); Wang, Xiaosu, E-mail: xiaosuwang@cau.edu.cn [Department of Applied Physics, College of Science, China Agricultural University, Beijing 100083 (China); Department of Physics, Tsinghua University, Beijing 100084 (China)

    2014-03-28

    The structural, electronic and dynamical properties of the cubic, tetragonal and rhombohedral phases of a lead-free ferroelectrics, (Na{sub 0.5}Bi{sub 0.5})TiO{sub 3} (NBT), have been studied with a density functional formalism. The direct band gap is determined to be 2∼3 eV for three phases, suggesting them to be good optical material. The equilibrium structures were given, and the importance of Bi atom in the low-symmetry ferroelectric phases were investigated with the electron localization functions analysis. The vibration modes at the Γ point were calculated to provide a basis for analyzing the Raman and IR spectra. Soft modes were found in both the cubic and the tetragonal phases, providing a clue in understanding the ferroelectric phase transition in NBT.

  10. Origin of the stabilization of the metastable tetragonal high-pressure phase in SrCuO2 thin films grown on SrTiO3 substrates by pulsed laser deposition

    Science.gov (United States)

    Mihailescu, C. N.; Pasuk, I.; Straticiuc, M.; Nita, C. R.; Pantelica, D.; Giapintzakis, J.

    2014-11-01

    In this work we have systematically investigated the evolution of structure and stoichiometry in SrCuO2 films grown on TiO2-terminated SrTiO3 substrates as a function of the substrate temperature. Depending on the growth temperature SrCuO2/SrTiO3 films can exhibit either a pure tetragonal high-pressure phase, or a pure orthorhombic low-pressure phase, or a mixed phase. Our results indicate that at low substrate temperatures the non-equilibrium state of the growth process is responsible for the stabilization of the metastable tetragonal high-pressure structure in SrCuO2 thin films grown on (0 0 1) SrTiO3 substrates, whose lattice matches the metastable structure. In addition, at higher substrate temperatures thermodynamics become dominant over other factors and the SrCuO2 thin films are stabilized in the thermodynamically stable orthorhombic phase.

  11. Theoretical studies of the local structure and electron paramagnetic resonance parameters for tetragonal VO{sup 2+} in C{sub 6}H{sub 7}KO{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Ping [Chongqing Jiaotong Univ. (China). School of Science; Li, Ling [Sichuan University of Arts and Science, Dazhou (China). Dept. of Maths and Finance-Economics

    2015-07-01

    The optical spectra, electron paramagnetic resonance parameters (i.e., the spin Hamiltonian parameters, including paramagnetic g factors and the hyperfine structure constants A{sub i}) and the local distortion structure for the tetragonal VO{sup 2+} in C{sub 6}H{sub 7}KO{sub 7} are theoretically studied based on the crystal-field theory and three-order perturbation formulas of a 3d{sup 1} centre in tetragonal site. The magnitude of orbital reduction factor, core polarisation constant κ, and local structure parameters are obtained by fitting the calculated optical spectra and electron paramagnetic resonance parameters to the experimental values. The theoretical results are in reasonable agreement with the experimental values.

  12. Superconducting and non-superconducting tetragonal (Ca sub 1-x B sub x La)(Cu sub 3-y M sub y )O sub 7-. delta. single crystals (M = Al, Pt)

    Energy Technology Data Exchange (ETDEWEB)

    Amador, U.; Moran, E.; Alario-Franco, M. (Dept. Q. Inorg. F.C. Quimicas, Univ. Complutense, Madrid (Spain)); Vegas, A.; Martinez-Ripoll, M. (Inst. Rocasolano, C.S.I.C., Madrid (Spain)); Ibanez, J. (C.E.N.I.M., C.S.I.C., Madrid (Spain)); Torrance, J.B. (I.B.M. Almaden Research Div., San Jose, CA (USA))

    1989-12-01

    Single crystal growth of the title phases has been achieved by a particular flux method. Depending on the crucibles used, copper is partially substituted either by aluminum or platinum but in different concentrations and on different sites. Al-substituted crystals are non-superconducting while the Pt-substituted ones are superconducting with Tc {proportional to} 50K. Both crystals have a tetragonal 123-type structure. (orig.).

  13. Mixed (oxigen ion and n-type) conductivity and structural characterization of stabilized tetragonal zirconia in the ZrO{sub 2}-CeO{sub 2}-TiO{sub 2} system

    Energy Technology Data Exchange (ETDEWEB)

    Capel, F.; Moure, C.; Duran, P. [Consejo Nacional de Investigaciones Cientificas, Madrid (Spain). Ist. de Ceramica y Vidrio

    2002-07-01

    By using X-ray diffraction lattice parameter measurements and Raman spectroscopy studies, the solid solubility limits of titania in ceria tetragonal zirconia solid solutions (Ce-TZP, 12 mol % CeO{sub 2}) have been established. Electrical properties of the mixed conductor TiO{sub 2}-CeTZP containing 5 and 10 mol % TiO{sub 2} were measured at the 300 C to 900 C temperature range in air and in reduced oxygen partial pressures. (orig.)

  14. Influence of core design, production technique, and material selection on fracture behavior of yttria-stabilized tetragonal zirconia polycrystal fixed dental prostheses produced using different multilayer techniques: split-file, over-pressing, and manually built-up veneers

    OpenAIRE

    Mahmood, Deyar Jallal Hadi; Linderoth, Ewa H; Wennerberg, Ann; Vult Von Steyern, Per

    2016-01-01

    Deyar Jallal Hadi Mahmood, Ewa H Linderoth, Ann Wennerberg, Per Vult Von Steyern Department of Prosthetic Dentistry, Faculty of Odontology, Malmö University, Malmö, Sweden Aim: To investigate and compare the fracture strength and fracture mode in eleven groups of currently, the most commonly used multilayer three-unit all-ceramic yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) fixed dental prostheses (FDPs) with respect to the choice of core material, veneering ma...

  15. Observações sôbre o bronzeado do algodoeiro Mocó Observations on bronzing of the Mocó cotton

    Directory of Open Access Journals (Sweden)

    A. S. Costa

    1955-01-01

    Full Text Available Uma anomalia do algodoeiro Mocó, denominada bronzeado, vem sendo observada na região do Seridó, Rio Grande do Norte, durante os últimos três anos. Pensou-se, a princípio, que esta anomalia fôsse causada por um vírus, mas as observações relatadas neste trabalho indicam que é causada por um ácaro. As fôlhas das plantas afetadas, especialmente aquelas da metade superior dos galhos, mostram uma coloração bronzeada no lado de baixo. Essa face da fôlha tem também uma superfície rugosa, com brilho vidrado (est. 1, B, as vezes com pequenas áreas de tecido cicatricial. Vistas pelo lado de cima são mais rugosas do que as normais e têm os bordos curvados para baixo. Nos casos graves, as fôlhas do topo dos galhos morrem e caem (est. 2, A e B. A espécie de ácaro causadora do bronzeado do algodoeiro Mocó foi identificada por H. H. Keifer, Sacramento, Calif., como pertencente a um gênero ainda não descrito da família Eriophyidae. Esta espécie está sendo presentemente denominada Anthocoptes sp. até que a sua descrição seja publicada. Populações de 500 a 1.000 indivíduos por centímetro quadrado de fôlha já foram encontradas. Esse ácaro parece ser muito sensível às condições do ambiente, visto que as populações da praga variam entre grandes limites.For the last three years a bronzing anomaly of cotton plants of the Mocó variety (Gossypium hirsutum L. var. maria galante Hutch. has been recorded in the Seridó region (a semi-arid region in the north-eastern part of Brazil, state of Rio Grande do Norte. This anomaly was first thought to be of virus origin, but the observations reported in this paper indicated that it is due to the attack by a species of mite. Leaves from affected plants, especially those on the upper half of the branches, show a bronzing discoloration on the dorsal side, frequently accompanied by a rough and ventral side of these leaves shows some rugosity not present in normal leaves, and in most cases

  16. METHODOLOGICAL DEVELOPMENTS IN 3D SCANNING AND MODELLING OF ARCHAEOLOGICAL FRENCH HERITAGE SITE : THE BRONZE AGE PAINTED CAVE OF "LES FRAUX", DORDOGNE (FRANCE

    Directory of Open Access Journals (Sweden)

    A. Burens

    2013-07-01

    Full Text Available For six years, an interdisciplinary team of archaeologists, surveyors, environmentalists and archaeometrists have jointly carried out the study of a Bronze Age painted cave, registrered in the French Historical Monuments. The archaeological cave of Les Fraux (Saint-Martin-de-Fressengeas, Dordogne forms a wide network of galleries, characterized by the exceptional richness of its archaeological remains such as ceramic and metal deposits, parietal representation and about domestic fireplaces. This cave is the only protohistorical site in Europe wherein are gathered testimonies of domestic, spiritual and artistic activities. Fortunately, the cave was closed at the end of the Bronze Age, following to the collapse of its entrance. The site was re-discovered in 1989 and its study started in 2007. The study in progress takes place in a new kind of tool founded by the CNRS's Institute of Ecology and Environment. The purpose of this observatory is the promotion of new methodologies and experimental studies in Global Ecology. In that framework, 3D models of the cave constitute the common work support and the best way for scientific communication for the various studies conducted on the site by nearly forty researchers. In this specific context, a partnership among archaeologists and surveyors from INSA Strasbourg allows the team to develop, in an interdisciplinary way, new methods of data acquiring based on contact-free measurements techniques in order to acquire a full 3D-documentation. This work is conducted in compliance with the integrity of the site. Different techniques based on Terrestrial Laser Scanning, Digital Photogrammetry and Spatial Imaging System have been used in order to generate a geometric and photorealistic 3D model from the combination of point clouds and photogrammetric images, for both visualization and accurate documentation purposes. Various scales of acquiring and diverse resolutions have been applied according to the subject

  17. Technological and stylistic evaluation of the Early Bronze Age pottery at Tarsus-Gozlukule, Turkey: Pottery production and its interaction with economic, social, and cultural spheres

    Science.gov (United States)

    Unlu, Elif

    This dissertation presents a technological and stylistic assessment of Early Bronze Age pottery production at Tarsus-Gozlukule, a multi-period mound settlement located in the Cilician Plain in southern Turkey. Pottery production, like all other man-made objects, is firstly a technological act. This dissertation maintains that material style (involving formal, technical, and decorative choices expressed by the artisan) of an artifact should be investigated as a whole as such an integrative study would be the most adequate way of understanding economic circumstances, social representation, and cultural boundaries. To facilitate this integrative investigation, seventy-two samples of Early Bronze Age pottery excavated from Tarsus-Gozlukule in the 1930s and 1940s.were selected for mineralogical, morphological, and chemical analyses. Petrographic and powder X-Ray Diffraction analyses were performed to determine the mineralogical makeup, Environmental Scanning Electron Microscope imagery was used to determine the morphology of these samples, and semi-quantitave Energy Dispersive X-Ray Spectroscopy analysis was performed on some samples to determine chemical properties of the clays. As a result of these scientific analyses various fabric groups were established. Afterwards formal shape and stylistic analysis was performed where shapes and surface treatments of the samples were analyzed and compared to the known local and non-local examples. Such an integrative approach to pottery production facilitates a better definition of the local pottery production process and enables an assessment of the technological know-how of the local pottery producers, their labor organization and its role within the operating markets, their function within the sociopolitical structure, and how such issues relate to the cultural boundaries within the community. Defining the paradigm of the local pottery production process leads to a broader investigation of issues related to the technological

  18. Bond strength of resin cement to yttrium-stabilized tetragonal zirconia ceramic treated with air abrasion, silica coating, and laser irradiation.

    Science.gov (United States)

    Akyil, Musa Samil; Uzun, Ismail Hakki; Bayindir, Funda

    2010-12-01

    The purpose of this study was to evaluate the shear bond strength of a resin cement to yttrium-stabilized tetragonal zirconia (Y-TZP) surfaces treated with air abrasion, silica coating, or CO(2), Er:YAG, or Nd:YAG laser irradiation, or irradiated by each laser after air abrasion. Optimized methods are needed to improve the adhesive bonding between resin cement and Y-TZP ceramic. Twelve specimens were irradiated with each laser at different parameters and examined by scanning electron microscopy to determine which parameters to use in this study. One hundred forty-one Y-TZP discs were assigned to nine groups: C, no treatment; AA, air abrasion; CJ, silica coating; ER, Er:YAG laser; ND, Nd:YAG laser; CO, CO(2) laser; AA+ER, air abrasion + Er:YAG laser; AA+ND, air abrasion + Nd:YAG laser; AA+CO, air abrasion + CO(2) laser. The composite cylinders were fabricated. After the surface treatments, the specimens were silanized and composite cylinders were cemented with the resin cement. The shear bond strength test was performed after specimens were stored in water for 24 h and after thermocycling for 500 cycles. The highest bond strength was obtained in the AA group and was similar to that of the CJ group. In C, ER, CO, ND, AA+ND, and AA+CO groups, the shear bond strengths were similar to each other according to the Duncan test results. The lowest bond value was obtained in the AA+ER group. Although air abrasion and silica coating were the most effective surface treatment methods, CO(2) and Er:YAG laser irradiation alone or Nd:YAG laser irradiation after air abrasion may be used as an alternative treatment method to increase the bond strength between resin cement and Y-TZP material.

  19. Sol–gel dip coating of yttria-stabilized tetragonal zirconia dental ceramic by aluminosilicate nanocomposite as a novel technique to improve the bonding of veneering porcelain

    Science.gov (United States)

    Madani, Azamsadat; Nakhaei, Mohammadreza; Karami, Parisa; Rajabzadeh, Ghadir; Salehi, Sahar; Bagheri, Hossein

    2016-01-01

    The aim of this in vitro study was to evaluate the effect of silica and aluminosilicate nanocomposite coating of zirconia-based dental ceramic by a sol–gel dip-coating technique on the bond strength of veneering porcelain to the yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in vitro. Thirty Y-TZP blocks (10 mm ×10 mm ×3 mm) were prepared and were assigned to four experimental groups (n=10/group): C, without any further surface treatment as the control group; S, sandblasted using 110 μm alumina powder; Si, silica sol dip coating + calcination; and Si/Al, aluminosilicate sol dip coating + calcination. After preparing Y-TZP samples, a 3 mm thick layer of the recommended porcelain was fired on the coated Y-TZP surface. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis were used to characterize the coating and the nature of the bonding between the coating and zirconia. To examine the zirconia–porcelain bond strength, a microtensile bond strength (μTBS) approach was chosen. FT-IR study showed the formation of silica and aluminosilicate materials. XRD pattern showed the formation of new phases consisting of Si, Al, and Zr in coated samples. SEM showed the formation of a uniform coating on Y-TZP samples. Maximum μTBS values were obtained in aluminosilicate samples, which were significantly increased compared to control and sandblasted groups (P=0.013 and Pveneering porcelain. PMID:27478376

  20. Influence of Different Framework Designs on the Fracture Properties of Ceria-Stabilized Tetragonal Zirconia/Alumina-Based All-Ceramic Crowns

    Directory of Open Access Journals (Sweden)

    Tomofumi Sawada

    2016-05-01

    Full Text Available The aim of this study was to evaluate the fracture load and failure mode of all-ceramic crowns with different ceria-stabilized tetragonal zirconia/alumina nanocomposite (Ce-TZP/A framework designs. Four frameworks (anatomical shape: AS, with a buccal or lingual supporting structure: BS and LS, or buccal and lingual supporting structures: BLS were fabricated. All frameworks were veneered with porcelain to fabricate all-ceramic crowns followed by cementation to tooth analogs. The fracture load of each crown either without or with pre-loading (1.2 million cycles, 49 N was measured. The failure mode was classified into partial or complete fracture. Differences were tested for significance (p < 0.05 by a two-way Analysis of Variance (ANOVA, followed by Tukey’s test and by Fisher’s exact test, respectively. Without pre-loading, supporting structures did not influence the fracture load or failure mode. Partial fractures were the most common failure mode. Pre-loading promoted the severity of the failure mode, although the fracture load among the framework designs was not influenced. In the AS group, prefailures were observed during pre-loading, and complete fractures were significantly increased after pre-loading. In contrast, the failure mode of the BLS group remained unchanged, showing only partial fracture even after pre-loading. This Ce-TZP/A framework design, comprised of an anatomical shape with additional buccal and lingual structures, has the potential to reduce the chipping of the veneering porcelain.

  1. Sol-gel dip coating of yttria-stabilized tetragonal zirconia dental ceramic by aluminosilicate nanocomposite as a novel technique to improve the bonding of veneering porcelain.

    Science.gov (United States)

    Madani, Azamsadat; Nakhaei, Mohammadreza; Karami, Parisa; Rajabzadeh, Ghadir; Salehi, Sahar; Bagheri, Hossein

    2016-01-01

    The aim of this in vitro study was to evaluate the effect of silica and aluminosilicate nanocomposite coating of zirconia-based dental ceramic by a sol-gel dip-coating technique on the bond strength of veneering porcelain to the yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in vitro. Thirty Y-TZP blocks (10 mm ×10 mm ×3 mm) were prepared and were assigned to four experimental groups (n=10/group): C, without any further surface treatment as the control group; S, sandblasted using 110 μm alumina powder; Si, silica sol dip coating + calcination; and Si/Al, aluminosilicate sol dip coating + calcination. After preparing Y-TZP samples, a 3 mm thick layer of the recommended porcelain was fired on the coated Y-TZP surface. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis were used to characterize the coating and the nature of the bonding between the coating and zirconia. To examine the zirconia-porcelain bond strength, a microtensile bond strength (μTBS) approach was chosen. FT-IR study showed the formation of silica and aluminosilicate materials. XRD pattern showed the formation of new phases consisting of Si, Al, and Zr in coated samples. SEM showed the formation of a uniform coating on Y-TZP samples. Maximum μTBS values were obtained in aluminosilicate samples, which were significantly increased compared to control and sandblasted groups (P=0.013 and Pveneering porcelain.

  2. Interface-specific reorientation of embedded tetragonal ZrO{sub 2} particles in Ni{sub 1-x}O polycrystals

    Energy Technology Data Exchange (ETDEWEB)

    Li, M.-Y. [Institute of Materials Science and Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Shen Pouyan [Institute of Materials Science and Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan (China)]. E-mail: pshen@mail.nsysu.edu.tw

    2005-05-25

    ZrO{sub 2}/Ni{sub 1-x}O (1:9 in molar ratio) composites were sintered and then annealed at 1650deg. C for 24 and 100h in air to study Ni{sub 1-x}O surface-controlled reorientation of the tetragonal (t-) ZrO{sub 2} particles, which transformed into monoclinic (m-) twin variants upon cooling. Transmission electron microscopy indicated that the ZrO{sub 2} particles fell into three topotaxial relationships with respect to the host Ni{sub 1-x}O grains: (1) parallel topotaxy (2) ''eutectic'' topotaxy, i.e. [100]{sub Z}//[111]{sub N}, [010]{sub Z}//[01-bar 1]{sub N} and (3) ''occasional'' topotaxy [100]{sub Z}//[111]{sub N}, [011-bar ]{sub Z}//[01-bar 1]{sub N}. The parallel topotaxy has a beneficial low energy for the family of {l_brace}100{r_brace}{sub Z,N} and {l_brace}111{r_brace}{sub Z,N} interfaces. The change from the occasional topotaxy to an energetically more favorable eutectic topotaxy was likely achieved by a rotation of the ZrO{sub 2} particles over a specific (100){sub Z}/(111){sub N} interface. Brownian-type rotation is probable for the embedded t-ZrO{sub 2} particles in terms of anchorage release at the interphase interface with the Ni{sub 1-x}O host. Detachment or bypassing of grain boundaries could also cause reorientation and shape change of intergranular ZrO{sub 2} particles.

  3. Growth kinetics of tetragonal and monoclinic ZrO{sub 2} crystallites in 3 mol% yttria partially stabilized ZrO{sub 2} (3Y-PSZ) precursor powder

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Chih-Wei [Department of Resources Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Lee, Kuen-Chan [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Yen, Feng-Lin, E-mail: flyen@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Shen, Yun-Hwei [Department of Resources Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Lee, Huey-Er [Department of Dentistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Department of Dentistry, Kaohsiung Medical University, Chung Ho Memorial Hospital, 100 Tzyou 1st Road, Kaohsiung 807, Taiwan (China); Wen, Shaw-Bing [General Education Center, Meiho Institute of Technology, 23 Pingguang Road, Neipu, Pingtung 91202, Taiwan (China); Wang, Moo-Chin, E-mail: mcwang@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Stack, Margaret Mary [Department of Mechanical and Aerospace Engineering, University of Strathclyde, 75 Montrose Street, Glasgow (United Kingdom)

    2014-04-01

    Highlights: • The crystalline structures were composed of tetragonal and monoclinic ZrO{sub 2}. • Growth kinetics of t-ZrO{sub 2} in the 3Y-PSZ precursor powder is described as: D{sub te}{sup 2}=(4.57±0.55)t{sup 0.12±0.02}exp(-((24.79±0.38)×10{sup 3})/(RT) ). • Growth kinetics of m-ZrO{sub 2} in the 3Y-PSZ precursor powder is described as: D{sub m}{sup 2}=(4.40±1.63)t{sup 0.17±0.08}exp(-((66.47±3.97)×10{sup 3})/(RT) ). - Abstract: The growth kinetics of tetragonal and monoclinic ZrO{sub 2} crystallites in 3 mol% yttria partially stabilized ZrO{sub 2} (3Y-PSZ) precursor powder has been investigated using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) specific surface area analysis, transmission electron microscopy (TEM) and high resolution TEM (HRTEM). After calcination of the 3Y-PSZ precursor powder between 773 and 1073 K for 2 h, the crystalline structures were composed of tetragonal and monoclinic ZrO{sub 2} as the primary and secondary phases, respectively. When the 3Y-PSZ precursor powder was calcined at 773 K for 2 h, the BET specific surface area was 97.13 m{sup 2}/g, which is equivalent to a particle size of 10.30 nm. The crystallite sizes determined via XRD and BET agreed well, indicating that the powder was virtually non-agglomerated. The growth kinetics of tetragonal and monoclinic ZrO{sub 2} crystallite isothermal growth in the 3Y-PSZ precursor powder are described by: D{sub te}{sup 2}=(4.57±0.55)t{sup 0.12±0.02}exp(-((24.79±0.38)×10{sup 3})/(RT) ) and D{sub m}{sup 2}=(4.40±1.63)t{sup 0.17±0.08}exp(-((66.47±3.97)×10{sup 3})/(RT) ), respectively, for 773K≤T≤1073K. D{sub te} and D{sub m} denote the crystallite size of tetragonal and monoclinic ZrO{sub 2} at time t and temperature T, respectively.

  4. L'apparition de l’écriture dans le monde égéen a l’Age du Bronze

    Directory of Open Access Journals (Sweden)

    René Treuil

    1999-12-01

    Full Text Available Este artigo tem por objetivo focalizar as etapas que levaram ao aparecimento da escrita, no mundo egeu, bem como discutir suas possíveis causas. O Neolítico presencia a passagem da marca simples, herdada do Paleolítico, ao verdadeiro signo, escrito sobre um tablete ou uma plaqueta, não tendo as pintaderas e as assim chamadas “pré-escritas” nada, provavelmente, a ver com esse fato. O Bronze Antigo, adotando o selo como instrumento de controle, associa o signo ao utensílio e, com as marcas de ceramista, utiliza o primeiro sistema de notação conhecido na região. Com o aparecimento do sistema palaciano, Creta amplia as utilizações precedentes e lhes acrescenta um segundo sistema de notação, representado pelas marcas de pedreiro; adota sobretudo, porem, a escrita hieroglífica, e, em seguida, a linear A para as necessidades da contabilidade palaciana e privada.

  5. Feasibility Study of Low Force Robotic Friction Stir Process and its Effect On Cavitation Erosion and Electrochemical Corrosion for Ni Al Bronze Alloys

    Science.gov (United States)

    Ahmad, Azman; Li, Huijun; Pan, Zengxi; Cuiuri, Dominic; van Duin, Stephen; Larkin, Nathan; Polden, Joseph; Lane, Nathan

    2014-12-01

    Robotic friction stir processing (FSP) has not been widely researched to date. This is perhaps due to the limited force capabilities of industrial robots in comparison with dedicated commercial FSP equipment. When operating a FSP machine, the force used to plunge the tools may range from 5000 to 8000 N which is currently beyond the capability of most robots. However, the capacity of robotic manipulators is increasing, so low force friction stir processing is becoming feasible. The ability of the robot arm to apply a controlled force that is normal to a 3-dimensional surface without the need to reorient the workpiece makes it a very useful tool for FSP of complex components. In this analysis, a robot arm with a capacity of 2500 N is used to improve the surface properties of nickel aluminum bronze (NAB) using low force FSP. Multiple passes were applied to the surface of the test sample for a more consistent spread of the stir zone. The sample was then microhardness tested and demonstrated a 62 pct increase in surface hardness. Cavitation erosion testing of the original and processed surfaces was also performed as per ASTM G-32. The erosion rate of the processed NAB sample was 44 pct of the rate experienced by the original cast NAB sample. Finally, the corrosion potentials of FSP NAB were measured at 45 mV less anodic than the unprocessed material, indicating that the processed material is more noble relative to the cast NAB sample.

  6. Anthracology and paleoecology in the south-eastern quadrant of the Iberian Peninsula: the contributions of the Bronze Age settlement of Terlinques (Villena, Alicante province

    Directory of Open Access Journals (Sweden)

    Machado Yanes, María del Carmen

    2009-06-01

    Full Text Available In this paper we present the results of the charcoal analyses from the Bronze Age settlement of Terlinques (Villena, Alicante. We discuss the predominance of Pinus halepensis in relation to the other woody species. Taking into account the environmental conditions (availability of materials and the bio-geographical context, the Villena Corridor is a frontier territory where floral and climatic influences of the Spanish Meseta and of the Iberian Southeast converge. Comparison with other anthracological and palynological studies allow us to propose some thoughts on palaeoecological changes in the Iberian Southeast.

    Se presentan los resultados del estudio antracológico del yacimiento de la Edad del Bronce de Terlinques (Villena, Alicante. Se discute el dominio de Pinus halepensis en relación a las otras especies leñosas. Teniendo en cuenta los condicionamientos ambientales (disponibilidad de la materia y el marco biogeográfico, el corredor de Villena es un territorio fronterizo donde convergen influencias climáticas y florísticas de la Meseta y del Sureste peninsular. Su comparación con otros estudios antracológicos y palinológicos permiten realizar algunas consideraciones sobre los cambios paleoecológicos en el sureste peninsular.

  7. The Somma-Vesuvius complex and the Phlaegrean Fields caldera: New chronological data of several eruptions of the Copper-Middle Bronze Age period

    Science.gov (United States)

    Passariello, Isabella; Lubritto, Carmine; D'Onofrio, Antonio; Guan, Yongjing; Terrasi, Filippo

    2010-04-01

    Radiocarbon dating of short-lived sample materials is a useful tool applied to date deposits of volcanic eruptions. Several archaeological sites discovered and excavated in Campania witnessed important volcanic eruptions, which occurred in the Copper and Middle Bronze Ages. These eruptions come from the Somma-Vesuvius complex and the Phlaegrean Fields caldera. At least four Plinian eruptions have been identified in the eruptive history of Somma-Vesuvius, interspersed by interplinian events, called protohistoric, which occurred between Avellino and Pompeii. At S. Paolo Belsito a stratigraphic sequence below Avellino and above the first two protohistoric events after Avellino were highlighted; while Nola (Naples) gives new information on the chronology of Avellino. Sites like Caivano and Gricignano D'Aversa, involved by the Agnano 3, Paleoastroni 2 and Agnano Monte Spina eruptions were highlighted and investigated. In this work, we want to clarify the chronology of some eruptions by comparing our results with previous data. Charcoal, bone and seed samples were collected, treated and measured at the CIRCE laboratory in Caserta.

  8. The Somma-Vesuvius complex and the Phlaegrean Fields caldera: New chronological data of several eruptions of the Copper-Middle Bronze Age period

    Energy Technology Data Exchange (ETDEWEB)

    Passariello, Isabella, E-mail: isabella.passariello@unina2.i [CIRCE - Dipartimento di Scienze Ambientali, II Universita di Napoli and INNOVA, via Vivaldi 43, Caserta 81100 (Italy); Lubritto, Carmine; D' Onofrio, Antonio [CIRCE - Dipartimento di Scienze Ambientali, II Universita di Napoli and INNOVA, via Vivaldi 43, Caserta 81100 (Italy); Guan, Yongjing [CIRCE - Dipartimento di Scienze Ambientali, II Universita di Napoli and INNOVA, via Vivaldi 43, Caserta 81100 (Italy); ICTP, Trieste (Italy); Terrasi, Filippo [CIRCE - Dipartimento di Scienze Ambientali, II Universita di Napoli and INNOVA, via Vivaldi 43, Caserta 81100 (Italy)

    2010-04-15

    Radiocarbon dating of short-lived sample materials is a useful tool applied to date deposits of volcanic eruptions. Several archaeological sites discovered and excavated in Campania witnessed important volcanic eruptions, which occurred in the Copper and Middle Bronze Ages. These eruptions come from the Somma-Vesuvius complex and the Phlaegrean Fields caldera. At least four Plinian eruptions have been identified in the eruptive history of Somma-Vesuvius, interspersed by interplinian events, called protohistoric, which occurred between Avellino and Pompeii. At S. Paolo Belsito a stratigraphic sequence below Avellino and above the first two protohistoric events after Avellino were highlighted; while Nola (Naples) gives new information on the chronology of Avellino. Sites like Caivano and Gricignano D'Aversa, involved by the Agnano 3, Paleoastroni 2 and Agnano Monte Spina eruptions were highlighted and investigated. In this work, we want to clarify the chronology of some eruptions by comparing our results with previous data. Charcoal, bone and seed samples were collected, treated and measured at the CIRCE laboratory in Caserta.

  9. Electrical conductivity of the ionic conductor tetragonal (Bi2O31-x(Eu2O3x Condutividade elétrica do condutor iônico (Bi2O31-x(Eu2O3x tetragonal

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    S. Yilmaz

    2011-06-01

    Full Text Available Electrical conductivity of tetragonal β-phase (Bi2O31-x(Eu2O3x (0.01 ≤ x ≤ 0.10 %mol ceramic systems were investigated. The temperature and doping concentration dependences of the electrical conductivity were studied by four-point probe technique. The electrical conductivity increases with the increasing doping concentration and temperature. The highest value of the electrical conductivity is 0.013 Ω-1cm-1 (x = 0.05, 750 ºC for the β-phase at 670 ºC and 0.57 Ω-1cm-1 (x=0.05, 800 ºC in binary systems at 690 ºC. The phase transition which manifests itself by the jump in the conductivity curves was seen and verified by differential thermal analysis measurements. The activation energies of the samples were found to be about 0.71-1.57 eV.Foi estudada a condutividade elétrica de sistema cerâmicos da fase β tetragonal (Bi2O31-x(Eu2O3x (0,01 ≤ x ≤ 0,10 mol%. A dependência da condutividade elétrica da temperatura e da concentração de dopantes foi estudada pela técnica das quatro pontas de prova. A condutividade elétrica aumenta com o aumento da concentração de dopantes e da temperatura. O maior valor da condutividade elétrica é 0,013 Ω-1cm-1 (x = 0,05, 750 ºC para a fase β a 670 ºC e 0,57 Ω-1cm-1 (x = 0,05, 800 ºC em sistema binários a 690 ºC. A transição de fase que se verifica pelo salto nas curvas de condutividade elétrica foi confirmada por medidas de análise térmica diferencial. As energias de ativação para as várias amostras está na faixa 0,71-1,57 eV.

  10. Cubic-tetragonal phase transition in Ca sub 0 sub . sub 0 sub 4 Sr sub 0 sub . sub 9 sub 6 TiO sub 3 a combined specific heat and neutron diffraction study

    CERN Document Server

    Gallardo, M C; Romero, F J; Cerro, J D; Seifert, F; Redfern, S A T

    2003-01-01

    The specific heat corresponding to the tetragonal-to-cubic transition in Ca sub 0 sub . sub 0 sub 4 Sr sub 0 sub . sub 9 sub 6 TiO sub 3 perovskite has been measured by conduction calorimetry. The order parameter of the transition has been obtained by means of neutron diffraction at low temperatures. Comparison of calorimetric data with the evolution of the order parameter indicates that this transition seems to follow a mean field Landau potential as in SrTiO sub 3. The linear behaviour of the excess of entropy versus temperature suggests that a 2-4 Landau potential is sufficient to describe the transition.

  11. Synthesis and structural characterization of highly tetragonal (1-x)Bi(Zn{sub 1/2}Ti{sub 1/2})-xPbTiO{sub 3} piezoceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Jyoti; Pandey, Rishikesh; Singh, Akhilesh Kumar [School of Materials Science and Technology, Indian Institute of Technology, Banaras Hindu University, Varanasi- 221005 (India)

    2013-02-05

    We present here the comprehensive X-ray diffraction (XRD) and dielectric measurement of (1-x)Bi(Zn{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} (BZT-xPT) piezoceramics with x=0.65, 0.70, 0.75 and 0.80. Powder X-ray diffraction data reveals the tetragonal structure (space group P4mm) of BZT-xPT ceramics for all the compositions.

  12. An interdisciplinary tillage erosion experiment: establishing a new field in grassland with reconstructed ard plough of the Bronze Age - Iron Age

    Science.gov (United States)

    Pavelka, Jan; Smetanová, Anna; Rejman, Jerzy; Kováčik, Peter

    2017-04-01

    Despite recognising the role of tillage erosion in landforms evolution, little research has documented its effects in prehistoric times. Herein, an interdisciplinary archaeological-geomorphological experiment with reconstructed tillage tools and management was conducted in order to measure tillage erosion when a new field in grasslands was established in the Bronze Age-Iron Age. Three wooden ards were reconstructed based on archaeological findings. They were tested in a cross-tillage experiment, consisting of a tillage pass perpendicular to the primary slope (6.5-9.7%), and a second tillage pass parallel to the primary slope of a convex-convex ridge with mowed grass (0.2 m high, vegetation cover >90%). The standard sole ard proved to be the most effective, with a mean tillage depth of 0.12 m, a mean tillage speed of 3.8 km h-1, and a mean distance between furrows of 0.20-0.25 m. Only 13% of the 264 tracers placed on 6 transects were displaced, and the mean tracers displacement parallel to the primary slope was 0.04 ± 0.17 m. Contour tillage perpendicular to primary slope created V or U shaped furrows with a mean depth of 0.1-0.12 m, a mean width of 0.05-0.1 m, and incision under the main root zone. Only soil in direct contact with the ard was displaced, with a mean translocation distance of 0.06 ± 0.2 m parallel and 0.06 ± 0.3 m perpendicular to the primary slope. During tillage parallel to slope, soil clods of 0.20 x 0.25 x 0.10 m were created and slightly disturbed or turned over one another. The tracers moved within the furrows and with the soil clods. Loose soil, resembling a seedbed, was not covered by soil clods. Mean displacement during the second pass was 0.03 ± 0.19 m parallel and 0.00 ± 0.15 m perpendicular to primary slope. The displacement from cross-tillage with a wooden ard in permanent grasslands was lower than many previously measured values of traditional animal-powered metal ploughs in permanent fields. No relationship between mean soil

  13. Study of settlement distribution pattern in the Kolkheti lowland (Black Sea coast of Georgia) starting from early Bronze Age - natural and human influence and adaptation to landscape evolution

    Science.gov (United States)

    Elashvili, Mikheil; Akhvlediani, Dimitri; Navrozashvili, Levan; Sukhishvili, Lasha; Kirkitadze, Giorgi; Kelterbaum, Daniel; Laermans, Hannes

    2015-04-01

    During the past decades the question of a changing environment/nature became crucial. Actually we are trying to understand its nature or to predict future changes and their possible effects represent the main goals of many interdisciplinary studies. Therefore, the study of paleoenvironmental changes delivers key information for a better understanding of the whole process and especially the influence of these changes on human society. The selected research topic is dictated by the fact that the Colchis lowland played an important role in the history of old societies (countries and empires). Especially the interaction between developing human societies under the pressure of a changing environment are most interesting in this context. The Kolkheti valley and the Black Sea shore represent a region involved in many global historical events, starting from the Myth of Argonauts and followed by the ancient greek colonization, the Kingdom of Pontus ending at the Roman and Byzantine empires. River Phasis (present Rioni) was an important segment in trade way between the Mediterranean and India and the East in general. In addition it is the area of the "lost or vanished" city of Phasis, an ancient and early medieval city, founded in the 7th or 6th century BC as a colony of the Milesian Greeks at the mouth of the river Phasis, near the modern-day seaport Poti. Considering the local history of Georgia, this is the area of formation of the Kolkhys (Colchis) culture in late bronze-early iron periods, forming Colchis and later on the Lazika kingdoms. It is important to note that the archaeology and geomorphology of the seashore of Georgia is rather scarcely studied (mainly in the 1970s during soviet era). It is quite clear that the history of the region will not be deciphered without the reconstruction of the paleo and historical environment. The study based on an ongoing collaboration between the University of Cologne and the Ilia State University. Actually, geomorphological and

  14. X-ray screening of the artificially deformed skulls from the Middle Bronze Age of the Low Volga region (paleopathology aspect

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    Pererva Evgenii Vladimirovich

    2013-11-01

    Full Text Available The impact of the deforming structure on the human skull is one of the most challenging and debated questions in modern archeology and anthropology related to artificial deformation of the skull. This is precisely why the present study attempts to study the pathological artificially deformed skulls of representatives of the Catacomb culture originating from burial mound in the Lower Volga region. The analysis of the bone material was carried out with the use of X-ray method of the frontal and lateral views. Thirteen radiographs of skulls with traces of deliberate artificial deformation were examined. The skull shapes, structure of the skull calvarial bones, state of the cranial sutures, signs of intracranial hypertension, and symptoms of vascular and endocrine pathologies were explored and evaluated. The study discovered that Catacomb culture bearers used a variety of methods of skull deformation. Front occipital, occipital ring strain and conventional acrocephaly deformation modes were revealed. The viability and compatibility with normal human activity of artificial skull deformation was observed. In the childhood and newborn periods, individuals have applied constrictive and restrictive devices, trusses andother appliancesfor a few years, their impact couldresultin the intracranial hypertension syndrome, as well as in problems with cranial sutures obliteration. It is very much likely that the use of strain could stimulate the development of the internal frontal hyperostosis (Morgagni's disease which contributed to the emergence of endocrine abnormities in humans. The increased trauma rate of skeleton bones was observed in population of the Middle Bronze Age, as well as ear diseases which makes us once again address the issue of social and cultural phenomenon of intentional artificial deformation of the head tradition.

  15. Appointing silver and bronze standards for noncovalent interactions: A comparison of spin-component-scaled (SCS), explicitly correlated (F12), and specialized wavefunction approaches

    Science.gov (United States)

    Burns, Lori A.; Marshall, Michael S.; Sherrill, C. David

    2014-12-01

    A systematic examination of noncovalent interactions as modeled by wavefunction theory is presented in comparison to gold-standard quality benchmarks available for 345 interaction energies of 49 bimolecular complexes. Quantum chemical techniques examined include spin-component-scaling (SCS) variations on second-order perturbation theory (MP2) [SCS, SCS(N), SCS(MI)] and coupled cluster singles and doubles (CCSD) [SCS, SCS(MI)]; also, method combinations designed to improve dispersion contacts [DW-MP2, MP2C, MP2.5, DW-CCSD(T)-F12]; where available, explicitly correlated (F12) counterparts are also considered. Dunning basis sets augmented by diffuse functions are employed for all accessible ζ-levels; truncations of the diffuse space are also considered. After examination of both accuracy and performance for 394 model chemistries, SCS(MI)-MP2/cc-pVQZ can be recommended for general use, having good accuracy at low cost and no ill-effects such as imbalance between hydrogen-bonding and dispersion-dominated systems or non-parallelity across dissociation curves. Moreover, when benchmarking accuracy is desirable but gold-standard computations are unaffordable, this work recommends silver-standard [DW-CCSD(T**)-F12/aug-cc-pVDZ] and bronze-standard [MP2C-F12/aug-cc-pVDZ] model chemistries, which support accuracies of 0.05 and 0.16 kcal/mol and efficiencies of 97.3 and 5.5 h for adenine.thymine, respectively. Choice comparisons of wavefunction results with the best symmetry-adapted perturbation theory [T. M. Parker, L. A. Burns, R. M. Parrish, A. G. Ryno, and C. D. Sherrill, J. Chem. Phys. 140, 094106 (2014)] and density functional theory [L. A. Burns, Á. Vázquez-Mayagoitia, B. G. Sumpter, and C. D. Sherrill, J. Chem. Phys. 134, 084107 (2011)] methods previously studied for these databases are provided for readers' guidance.

  16. Dielectric and ferroelectric characteristics of Ba{sub 4}Pr{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30} tungsten bronze ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Ting Ting; Chen, Wang; Zhu, Xiao Na; Zhu, Xiao Li; Chen, Xiang Ming, E-mail: xmchen59@zju.edu.cn

    2016-09-15

    Ba{sub 4}Pr{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30} tungsten bronze ceramics have been prepared by a standard solid-state sintering method, and the electrical, dielectric and ferroelectric properties have been determined together with the structure. The structure dependence of ferroelectricity has been investigated by comparing the as-sintered, N{sub 2}-annealed and O{sub 2}-annealed samples. The typical relaxor ferroelectric nature is generally indicated in the present ceramics, where the broaden dielectric constant and dielectric loss peaks with strong frequency dispersion feature are observed. The peak temperatures for both dielectric constant and dielectric loss are significantly increased together with the much stronger frequency dispersion by N{sub 2}-annealing, while the O{sub 2}-annealing results in the decreased peak temperatures and the suppressed frequency dispersion. These phenomena are closely related to the valences of Fe and Pr ions. The hopping between Fe{sup 2+} and Fe{sup 3+} inside the grains causes the dielectric relaxation in as-sintered and N{sub 2}-annealed samples. The enhanced ferroelectricity near room temperature is attributed to the increased ion radius difference between A1 and A2 ions because of the “substitution” Pr{sup 4+} for Pr{sup 3+} after N{sub 2}-annealing. - Highlights: • Dielectric and ferroelectric properties of Ba{sub 4}Pr{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30} are investigated. • Ferroelectric hysteresis loop is observed in Ba{sub 4}Pr{sub 2}Fe{sub 2}Nb{sub 8}O{sub 30} ceramics. • The ferroelectric properties are closely related to the valences of Pr ions. • The ferroelectric transition temperature is dominated by the radius difference between A1-and A2-site.

  17. Did a drought crisis lead to cultural changes in Eolian Islands during the Bronze Age? New data from archaeological excavations and carbon isotopes analysis of archaeobotanical remains

    Science.gov (United States)

    Fiorentino, Girolamo; Caracuta, Valentina; Martinelli, Maria Clara; Quarta, Gianluca; Calcagnile, Lucio

    2010-05-01

    Agricultural potential is commonly regarded as a key factor for the development of pre-modern complex societies in Mediterranean regions. For this reason, the assessment of paleo-rainfall regimes is considered fundamental to understand the influence of short-term climate fluctuations on ancient human communities, especially in those areas characterised by critical environmental conditions such as Eolian archipelagos. Usually, plant remains in archaeological contexts are used to assess agricultural practices and any strategies adopted by ancient populations to face climate changes. Within this work we intend to extend the traditional archaeobotanical approach by using carbon isotope analysis of ancient plant remains in order to infer paleorainfall trends. For this purpose fourty samples of plant remains recovered from Bronze Age archaeological contexts recently excavated in Filicudi and Salina islands, Eolian archipelagos, were selected to be submitted to AMS (Accelerator Mass Spectrometry) radiocarbon dating, archaeobotanaical and carbon stable isotopes analyses. This approach allowed the reconstruction in the analyzed samples of the variation of the carbon isotope composition, expressed through the δ13C term, in a diachronic scale as obtained by the combined radiocarbon dating analyses performed on the same archaeological material. The obtained results show clear chronological pattern of variation of the δ13C term in the plant tissues which find correspondence with other climatic proxy records and from which paleoclimatic information have been inferred. From the archaeological point of view, the obtained results allow the evaluation of the influence of climate on the dynamics of population of Eolian island by reconsidering archaeological indicators coming from the recent excavations carried out in the sites of Filicudi and Salina.

  18. Abertura floral de Dendranthema grandiflora Tzvelev. ´Bronze Repin´após rmazenamento a frio seguido de “pulsing” Floral opening of Dendranthema grandiflora Tzvelev. ´Bronze Repin´after cold storage followed by pulsing

    Directory of Open Access Journals (Sweden)

    Rogério Antônio Bellé

    2004-02-01

    Full Text Available Visando estudar a abertura de inflorescências e a vida de vaso de crisântemo (Dendranthema grandiflora Tzvelev. ‘Bronze Repin’ colhido precocemente, montou-se um experimento em delineamento inteiramente casualizado bifatorial 2 x 6 com cinco repetições, realizado no Departamento de Fitotecnia da Universidade Federal de Santa Maria. As hastes foram armazenadas a 2ºC ou 5ºC por sete dias, sendo em seguida tratadas com soluções de “pulsing” por 24h e mantidas em vasos com água de torneira, renovada a cada dois dias. As soluções utilizadas foram: Água (testemunha; Tiosulfato de Prata-STS 11mg.L-1 (Crysal AVB; Ácido Giberélico-GA3 50mg.L-1 (Pro-gibb; Hipoclorito de Sódio-NaOCl 200mg.L-1; 8-Hidroxiquinolina-8-HQ 100mg.L-1; Tiabendazole-TIBA 100mg.L-1(Tecto 100. Com exceção da testemunha, as outras soluções continham 2% de Sacarose. Com estes tratamentos, observou-se que não foi possível uma abertura perfeita da inflorescência, mas a vantagem foi de prolongar a sua vida, podendo-se colocá-las no mercado num momento mais oportuno.The study of opening of inflorescences and the vase life (Dendranthema grandiflora Tzvelev. ‘Bronze Repin’ early picked of chysanthemum, was carried out in an experiment entirely set up in bifactorial 2 x 6 with five repetitions, at the Department of Fitotecnia of Santa Maria’s Federal University. The stems were stored at 2ºC or 5ºC for 7 days, prior to being treated with pulsing solutions for 24 hours and maintained in vases with distilled water, renewed every two days. The solutions used as follows: Water (control; Silver Thiosulfate-STS 11mg.L-1 (Crysal AVB; Giberelic Acid-GA3 50mg.L-1 (Pro-gibb; Sodium Hipochloride-NaOCl 200mg.L-1; 8-Hidroxyquinoline-8-HQ 100mg.L-1; Tiabendazole-TIBA 100mg.L-1 (Tecto 100. With the exception of the control, all solutions contained 2% sucrose. Perfect opening of the flower was not achieved, but vase life could be extended in order to place them in the

  19. orbital selective correlation reduce in collapse tetragonal phase of CaFe2(As0.935P0.065)2 and electronic structure reconstruction studied by angel resolved photoemission spectroscopy

    Science.gov (United States)

    Zeng, Lingkun

    We performed an angle-resolved photoemission spectroscopy (ARPES) study of the CaFe2(As0.935P0.065)2 in the collapse tetragonal(CT) phase and uncollapse tetragonal(UCT) phase. We find in the CT phase the electronic correlation dramatically reduces respective to UCT phase. Meanwhile, the reduction of correlation in CT phase show an orbital selective effect: correlation in dxy reduces the most, and then dxz/yz, while the one in dz2-r2 almost keeps the same. In CT phase, almost all bands sink downwards to higher binding energy, leading to the hole like bands around Brillouin zone(BZ) center sink below EF compared with UCT phase. However, the electron pocket around Brillouin Zone(BZ) corner(M) in UCT phase, forms a hole pocket around BZ center(Z point) in CT phase. Moreover, the dxy exhibits larger movement down to higher binding energy, resulting in farther away from dyz/xz and closer to dxy.We propose the electron filling ,namely high spin state in UCT phase to low spin state in CT phase(due to competing between crystal structure field and Hund's coupling), other than the Fermi surface nesting might be responsible for the absent of magnetic ordering.

  20. The botanical macroremains from the prehistoric settlement Kalnik-Igrišče (NW Croatia in the context of current knowledge about cultivation and plant consumption in Croatia and neighboring countries during the Bronze Age

    Directory of Open Access Journals (Sweden)

    Sara Mareković

    2015-07-01

    Full Text Available This paper presents the results of the first extensive archaeobotanical research into a Bronze Age site in Croatia. The aim of the study was to reveal what plants were consumed (grown at Kalnik-Igrišče (NW Croatia in the Bronze Age and to realize if the plant diet of the local population differed from that of the inhabitants in neighboring countries. The results show that all plant macrofossils found at Kalnik-Igrišče can be classified into one of four functional groups: cereals, cultivated legumes, useful trees and weeds. As much as 98% of the findings are of cereals and legumes. The most abundant species found are Panicum miliaceum (millet, Hordeum vulgare (barley, Vicia faba (faba bean, Triticum aestivum ssp. aestivum (bread wheat, Triticum turgidum ssp. dicoccon (emmer wheat and Lens culinaris (lentils. The findings from Kalnik-Igrišče do not differ from the findings of neighboring countries, indicating that there were similar diets and agricultural/plant-collecting activities throughout the whole of the studied area (Bosnia and Herzegovina, Slovenia, Serbia, Italy, Austria and Hungary.

  1. The Afragola settlement near Vesuvius, Italy: The destruction and abandonment of a Bronze Age village revealed by archaeology, volcanology and rock-magnetism

    Science.gov (United States)

    Di Vito, Mauro A.; Zanella, Elena; Gurioli, Lucia; Lanza, Roberto; Sulpizio, Roberto; Bishop, Jim; Tema, Evdokia; Boenzi, Giuliana; Laforgia, Elena

    2009-01-01

    Public works in progress in the Campanian plain north of Somma-Vesuvius recently encountered the remains of a prehistoric settlement close to the town of Afragola. Rescue excavations brought to light a Bronze Age village partially destroyed and buried by pyroclastic density currents (PDCs) of the Vesuvian Pomici di Avellino eruption (3.8 14C ka BP) and subsequently sealed by alluvial deposits. Volcanological and rock-magnetic investigations supplemented the excavations. Careful comparison between volcanological and archaeological stratigraphies led to an understanding of the timing of the damage the buildings suffered when they were struck by a series of PDCs. The first engulfed the village, located some 14 km to the north of the inferred vent, and penetrated into the dwellings without causing major damage. The buildings were able to withstand the weak dynamic pressure of the currents and deviate their path, as shown by the magnetic fabric analyses. Some later collapsed under the load of the deposits piled up by successive currents. Stepwise demagnetization of the thermal remanent magnetization (TRM) carried by potsherds embedded in the deposits yields deposition temperatures in the order of 260-320 °C, fully consistent with those derived from pottery and lithic fragments from other distal and proximal sites. The fairly uniform temperature of the deposits is here ascribed to the lack of pervasive air entrainment into the currents. This, in turn, resulted from the lack of major topographical obstacles along the flat plain. The coupling of structural damage and sedimentological analyses indicates that the currents were not destructive in the Afragola area, but TRM data indicate they were still hot enough to cause death or severe injury to humans and animals. The successful escape of the entire population is apparent from the lack of human remains and from thousands of human footprints on the surface of the deposits left by the first PDCs. People were thus able to

  2. Cooperative Jahn–Teller effect and the role of strain in the tetragonal-to-cubic phase transition in MgxCu1 − xCr2O4

    Science.gov (United States)

    Tarantino, Serena C.; Giannini, Mattia; Carpenter, Michael A.; Zema, Michele

    2016-01-01

    Temperature and composition dependences of the I41/amd → phase transition in the MgxCu1 − xCr2O4 spinel solid solution, due to the melting of the cooperative Jahn–Teller distortion, have been studied by means of single-crystal X-ray diffraction. Crystals with x = 0, 0.10, 0.18, 0.43, 0.46, 0.53, 1 were grown by flux decomposition methods. All crystals have been refined in the tetragonal I41/amd space group except for the Mg end-member, which has cubic symmetry. In MgxCu1 − xCr2O4 the progressive substitution of the Jahn–Teller, d 9 Cu2+ cation with spherical and closed-shell Mg2+ has a substantial effect on the crystal structure, such that there is a gradual reduction of the splitting of a and c unit-cell parameters and flattening of the tetrahedra. Single-crystal diffraction data collected in situ up to T = 1173 K show that the tetragonal-to-cubic transition temperature decreases with increasing Mg content. The strength of the Cu—Cu interaction is, in effect, modulated by varying the Cu/Mg ratio. Structure refinements of diffraction data collected at different temperatures reveal that heating results in a gradual reduction in the tetrahedron compression, which remains significant until near the transition temperature, however, at which point the distortion of the tetrahedra rapidly vanishes. The spontaneous strain arising in the tetragonal phase is large, amounting to 10% shear strain, e t, and ∼ 1% volume strain, V s, in the copper chromite end-member at room temperature. Observed strain relationships are consistent with pseudoproper ferroelastic behaviour ( ∝ V s ∝ , where q JT is the order parameter). The I41/amd → phase transition is first order in character for Cu-rich samples and then evolves towards second-order character. Although a third order term is permitted by symmetry in the Landau expansion, this behaviour appears to be more accurately represented by a 246 expansion with a change from negative to positive values of

  3. L’espace domestique au Bronze final et au premier âge du Fer dans le sud de la Corse

    Directory of Open Access Journals (Sweden)

    Peche-Quilichini, Kewin

    2015-12-01

    Full Text Available We present a synthetic approach to the kinds of housing found in the mountainous Alta Rocca sector of southern Corsica during the late Bronze Age and Early Iron Age. Study of protohistoric non-fortified sites in Corsica is relatively new, but the numerous projects carried out in recent years reveal the structural and developmental complexity of living spaces, thus permitting an initial comparative analysis. This is based mainly on the excavations of the large settlement of Cuciurpula that began in 2008 and are still in progress. It also makes use of the 2012 test pits in the villages of Puzzonu and Nuciaresa. The chronology of the areas that were studied cover the entire time span from the 12th to the 4th century B.C., and thus permit one to understand the developmental changes that occurred with respect to both the overall settlement organization and the internal space and architecture of the dwellings.El objetivo de este artículo es ofrecer un acercamiento sintético a las formas de hábitat en Córcega entre el Bronce final (BF y la primera Edad del Hierro (F1, a escala de la microrregión montañosa de la Alta Rocca, ubicada en el sur de Córcega en el corazón de la cuenca occidental del Mediterráneo. La problemática de estudio de los asentamientos protohistóricos sin fortificar es reciente en la isla, sin embargo, en los últimos años los estudios se han multiplicado y dan cuenta de la complejidad estructural y evolutiva de los espacios habitados, permitiendo así un primer análisis comparativo. El razonamiento se apoya esencialmente en la aportación de las excavaciones del gran hábitat de Cuciurpula, iniciadas en 2008 y todavía en curso, así como en la explotación de los poblados de Puzzonu y de Nuciaresa, sondeados en 2012. La cronología de los sectores estudiados permite abarcar un arco cronológico completo entre el siglo XII y el siglo VI a.C., y por tanto aprehender los fenómenos evolutivos, tanto en términos de

  4. Origin and distribution of slightly biconical bowls with facetted or channeled rim from the end of bronze and the beginning of iron ages on the Balkan peninsula: Contribution to the study of ethnic and cultural movements in southeast Europe at the end of bronze and the beginning of iron ages

    Directory of Open Access Journals (Sweden)

    Bulatović Aleksandar P.

    2009-01-01

    Full Text Available Slightly biconical shaped bowls, the upper cone (rim and shoulder of which is decorated with horizontal and slanted facets or slanted channels, as well as semi-globular bowls of inverted rim decorated with horizontal facets or slanted channels are characteristic of the end of Bronze Age and mark the beginning of Iron Age in many cultural groups within the Balkan Peninsula. Problem of their origin, chronology and distribution is present in archaeological literature for a long time. Many authors perceived the significance of this ceramic shape for the chronological, ethnic and cultural interpretation of the Late Bronze, that is, of the Early Iron Ages within the territory of the Balkans. Pottery from the burned layers in Vardina and Vardaroftsa sites in the north of Greece, among which there were bowls with inverted, slanted channeled rim, was designated way back by W. Heurtley as Danubian pottery or Lausitz ware, connecting its origin with the Danube Basin. Anumber of conclusions have been reached upon the study of finds of slightly biconical bowls and bowls of inverted rim, decorated with channels or facets, from several indicative sites from Late Bronze and Early Iron Ages within the Balkan Peninsula and south part of the Middle Europe. It has been stated that the bowls appear first within the southwest Slovakia and northwest Hungary in the Br D period, to spread very fast, already in the Br D/Ha A1 period, from its home territory to the east, to the northeast Hungary and northwest Romania. Namely, this first spreading wave into these territories brought along only variety Ia bowls, which were further distributed to the south, during the Ha A1 period, to the central parts of the Balkan Peninsula and consequently it can be concluded that these bowls are somewhat older than other varieties. In the period Br D - Ha A1, in north Hungary, under the influence of Gava Culture, on one hand, and Čaka Culture, on the other, appear also variety IIa bowls

  5. Le site proto-urbain de Dzharkutan durant les âges du bronze et du ferRecherches de la Mission archéologique franco-ouzbèke-Protohistoire

    OpenAIRE

    Bendezu-Sarmiento, Julio; Mustafakulov, Samariddin

    2014-01-01

    L’établissement et la nécropole de Dzharkutan, dans la vallée du Surkhan-Daria (Bactriane septentrionale), sont exceptionnels par leur extension géographique et chronologique pour la compréhension de la genèse, du développement et de la disparition des cultures proto-urbaines en Asie centrale (âge du bronze et début de l’âge du fer, IIIe-Ier millénaires avant n.è.). Découvert dans les années 1970, le site a été fouillé par des missions ouzbèkes puis germano-ouzbèkes sur des grandes surfaces c...

  6. A distinct section of the Early Bronze Age society? Stable isotope investigations of burials in settlement pits and multiple inhumations of the Únětice culture in central Germany.

    Science.gov (United States)

    Knipper, Corina; Fragata, Matthias; Nicklisch, Nicole; Siebert, Angelina; Szécsényi-Nagy, Anna; Hubensack, Vera; Metzner-Nebelsick, Carola; Meller, Harald; Alt, Kurt W

    2016-03-01

    Inhumations in so-called settlement pits and multiple interments are subordinate burial practices of the Early Bronze Age Únětice culture in central Germany (2200-1700/1650 BC). The majority of the Únětice population was entombed as single inhumations in rectangular grave pits with a normative position of the body. The goal of the study was to test archaeological hypotheses that the deviant burials may represent socially distinct or nonlocal individuals. The study comprised up to two teeth and one bone each of 74 human individuals from eight sites and faunal comparative samples. The inhumations included regular, deviant burials in so-called settlement or storage pits, and multiple burials. We investigated radiogenic strontium isotope compositions of tooth enamel ((87) Sr/(86) Sr) and light stable isotope ratios of carbon and nitrogen of bone collagen (δ(13) C, δ(15) N) aiming at the disclosure of residential changes and dietary patterns. Site-specific strontium isotope data ranges mirror different geological properties including calcareous bedrock, loess, and glacial till. Independent from burial types, they disclose low portions of nonlocal individuals of up to some 20% at the individual sites. The light stable isotope ratios of burials in settlement pits and rectangular graves overlap widely and indicate highly similar dietary habits. The analytical results let to conclude that inhumations in settlement pits and multiple burials were two of the manifold burial practices of the Early Bronze Age. The selection criteria of the individuals for the different forms of inhumation remained undisclosed. © 2015 Wiley Periodicals, Inc.

  7. Untitled

    Indian Academy of Sciences (India)

    NbOs solid solutions. At Ba? ) 0.2, the lattice becomes that of tetragonal tungsten bronze type for Nb = 0.90. (F) Mixed phases are observed between the various structure types-perovskite. (cubic and tetragonal), pyrochlore, and tungsten ...

  8. Off-site embankments to protect fields from the growth of peatlands in the Valli Grandi Veronesi Meridionali (Italy during Middle and Recent Bronze Age

    Directory of Open Access Journals (Sweden)

    Claudio Balista

    2016-12-01

    Full Text Available In the background of the late-Holocene landscape of the Southern Valli Grandi Veronesi (VGVM and nearby Bonifica Padana, an area that stretches between rivers Adige and Po and which is drained by the river Tartaro, was taken into consideration the position of a long embankment that ran through the territories of the two large moated sites of the middle and recent Bronze Age, Fondo Paviani (FP to east , and Castello del Tartaro (CdT to west. The location of this particular embankment called SAM (from italian southern embanked road, more than ten km long, and arranged parallel to the Tartaro old riparian belt, since long time attracted scholars as a witness of an old territorial organization, probably related to spatial distribution of cultivated or pasture by the communities who lived in the two large villages, bounded by massive ditch and bank systems. On the basis of recent acquisitions of new DEM and LIDAR sources and aimed field investigations, then merged into geo-chronological and chrono-typological analysis in the laboratory, was developed a research addressed the chrono-stratigraphic, cultural-evolutionary and functional scan of the SAM construct. For this purpose, the archaeological, stratigraphic and chronological record have been reviewed from a series of very significant off-sites, with stratigraphic columns documenting paleo-environmental and archaeological-functional reconstructions. They allowed to established the obvious links between the infrastructure of the ditches of the SAM embankment and the network of secondary rural ditches that seemed to drain and distribute waters in the parceled fields next to the large contemporary sites. In Ponte Moro off-site we captured the chrono-stratigraphic position of SAM embankment through the dating of two peat samples undertaken immediately before and after the stratigraphic position of the embankment. The datings have yielded an earliest date for the construction (MBA-RBA and a later date

  9. Society and economy in the Late Bronze Age and the early Iron Age in the Northeast of the Iberian Peninsula: an approach from the archaeological sources

    Directory of Open Access Journals (Sweden)

    López Cachero, F. Javier

    2007-06-01

    Full Text Available

    At the end of the Bronze Age, important changes took place among the communities of the northeast of the Iberian Peninsula. These changes continue during the seventh and sixth centuries B.C. and are characterized by a gradual formation of a warrior-type aristocracy. But this “elite” did not consolidate its power definitively until the early Iberian Period, establishing the social structure characteristic of the archaic states of the Iberian Period. Nevertheless, there are social differences among inland and coastal territories. In the inland areas (rivers Segre- Cinca, Guadalope and Matarraña-Algás these differences are the result of local development of societies and, in the coastal areas the main changes take place in parallel with a Phoenician trade, integrating them in the Mediterranean world-system. The local response to this phenomenon was not homogeneous. Differences include chronology, settlement processes and distribution of wealth. We analyze here recent studies on this subject, including the issue of the Urnfield Culture and give special emphasis to the main archaeological contributions of the last decade.  



    A finales de la Edad del Bronce comienzan a producirse importantes transformaciones en el seno de las comunidades del noreste peninsular que tendrán continuidad durante los siglos VII y VI ANE y que se caracterizarán por la paulatina formación de una clase aristocrática de

  10. Una aproximación paleodemográfica comparativa a la estructura de edad y sexo de las poblaciones de la Edad del Bronce en el interior peninsular = A comparative paleodemographic approach to age and sex structure of a Central Iberian Bronze Age populations

    Directory of Open Access Journals (Sweden)

    Alberto Pérez Villa

    2015-11-01

    Full Text Available Este artículo pretende mostrar la gran potencialidad de los estudios paleodemograficos. Para ello se recurre como caso de estudio a la población enterrada durante la Edad del Bronce (2200-1200 cal. AC en la cuenca media-alta del Tajo. Sus resultados nos permiten comprobar sí la muestra es representativa del conjunto de la sociedad, así como aproximarnos a las dinámicas demográficas de esos grupos sociales.This article suggest the great potential of palaeodemographic studies through the analysis of a specific case study: the population buried during the Bronze Age (2200–1200 BC cal. in the middle Tagus river basin. Results allow us to verify the representativeness of the sample, and to approach the population dynamics of Bronze Age groups.

  11. Heteroepitaxial growth of tetragonal Mn2.7−xFexGa1.3 (0 ≤ x ≤ 1.2 Heusler films with perpendicular magnetic anisotropy

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    Adel Kalache

    2017-09-01

    Full Text Available This work reports on the structural and magnetic properties of Mn2.7−xFexGa1.3 Heusler films with different Fe content x (0 ≤ x ≤ 1.2. The films were deposited heteroepitaxially on MgO single crystal substrates, by magnetron sputtering. Mn2.7−xFexGa1.3 films with the thickness of 35 nm were crystallized in a tetragonal D022 structure with (001 preferred orientation. Tunable magnetic properties were achieved by changing the Fe content x. Mn2.7−xFexGa1.3 thin films exhibit high uniaxial anisotropy Ku ≥ 1.4 MJ/m3, coercivity from 0.95 to 0.31 T, and saturation magnetization from 290 to 570 kA/m. The film with Mn1.6Fe1.1Ga1.3 composition shows high Ku of 1.47 MJ/m3 and energy product (BHmax of 37 kJ/m3 at room temperature. These findings demonstrate that Mn2.7−xFexGa1.3 films have promising properties for mid-range permanent magnet and spintronic applications.

  12. Influence of core design, production technique, and material selection on fracture behavior of yttria-stabilized tetragonal zirconia polycrystal fixed dental prostheses produced using different multilayer techniques: split-file, over-pressing, and manually built-up veneers.

    Science.gov (United States)

    Mahmood, Deyar Jallal Hadi; Linderoth, Ewa H; Wennerberg, Ann; Vult Von Steyern, Per

    2016-01-01

    To investigate and compare the fracture strength and fracture mode in eleven groups of currently, the most commonly used multilayer three-unit all-ceramic yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) fixed dental prostheses (FDPs) with respect to the choice of core material, veneering material area, manufacturing technique, design of connectors, and radii of curvature of FDP cores. A total of 110 three-unit Y-TZP FDP cores with one intermediate pontic were made. The FDP cores in groups 1-7 were made with a split-file design, veneered with manually built-up porcelain, computer-aided design-on veneers, and over-pressed veneers. Groups 8-11 consisted of FDPs with a state-of-the-art design, veneered with manually built-up porcelain. All the FDP cores were subjected to simulated aging and finally loaded to fracture. There was a significant difference (Pveneering materials and techniques tested in the study, split-file, over-press, built-up porcelains, and glass-ceramics are, with a great safety margin, sufficient for clinical use both anteriorly and posteriorly. Analysis of the fracture pattern shows differences between the milled veneers and over-pressed or built-up veneers, where the milled ones show numerically more veneer cracks and the other groups only show complete connector fractures.

  13. Mechanically reliable thermoelectric (TE) nanocomposites by dispersing and embedding TE-nanostructures inside a tetragonal ZrO2 matrix: the concept and experimental demonstration in graphene oxide-3YSZ system.

    Science.gov (United States)

    Estili, Mehdi; Wu, Wen-Wen; Khazaei, Mohammad; Sakka, Yoshio

    2014-02-01

    Novel low-dimensional thermoelectric (TE) materials suffer from poor mechanical reliability, which limits their applications, especially in mechanically harsh environments. Here, we propose a new concept, in which the novel, abundant, thermally stable TE-nanostructures are dispersed and then intimately embedded inside a protective, mechanically reliable tetragonal ZrO2 (TZP) ceramic matrix with a low thermal conductivity. We also demonstrate an experimental proof-of-principle verification of our concept in reduced-graphene oxide (GO)-3 mol% Y2O3-ZrO2 (3YSZ or 3Y-TZP) nanocomposite system. TE characterizations suggest that our protective TZP matrix does not degrade the intrinsic TE property of the reduced GO network. These preliminary results are promising and encouraging to start research on similar TZP-matrix TE-nanocomposites, which contain more effective TE-nanostructures with larger intrinsic power factors. In this regard, we propose a scalable approach for fabrication of similar dense TE-nanocomposites composed of other one-dimensional and/or two-dimensional TE-nanostructures, which involves an aqueous colloidal approach and a subsequent spark plasma sintering. These new TZP-matrix TE-nanocomposites could be used for sustainable clean power generation, especially in mechanically harsh environments with thermal/mechanical shocks and vibrations, where energy availability, reliability and durability are more important than the energy efficiency. Considering the excellent biocompatibility of TZP matrix, they could even be used inside the body to power implanted medical devices.

  14. Observation of stimulated Raman scattering in polar tetragonal crystals of barium antimony tartrate trihydrate, Ba[Sb{sub 2}((+)C{sub 4}H{sub 2}O{sub 6}){sub 2}].3H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Kaminskii, Alexander A. [Institute of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation); Rhee, Hanjo; Eichler, Hans J.; Lux, Oliver [Institute of Optics and Atomic Physics, Technical University of Berlin (Germany); Nemec, Ivan [Department of Inorganic Chemistry, Faculty of Science, Charles University, Prague (Czech Republic); Yoneda, Hitoki; Shirakawa, Akira [Institute for Laser Science, University of Electro-Communications, Tokyo (Japan); Becker, Petra; Bohaty, Ladislav [Section Crystallography, Institute of Geology and Mineralogy, University of Cologne (Germany)

    2017-04-15

    The non-centrosymmetric polar tetragonal (P4{sub 1}) barium antimony tartrate trihydrate, Ba[Sb{sub 2}((+)C{sub 4}H{sub 2}O{sub 6}){sub 2}].3H{sub 2}O, was found to be an attractive novel semi-organic crystal manifesting numerous χ{sup (2)}- and χ{sup (3)}-nonlinear optical interactions. In particular, with picosecond single- and dual-wavelength pumping SHG and THG via cascaded parametric four-wave processes were observed. High-order Stokes and anti-Stokes lasing related to two SRS-promoting vibration modes of the crystal, with ω{sub SRS1} ∼ 575 cm{sup -1} and ω{sub SRS2} ∼ 2940 cm{sup -1}, takes place. Basing on a spontaneous Raman investigation an assignment of the two SRS-active vibration modes is discussed. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Influence of core design, production technique, and material selection on fracture behavior of yttria-stabilized tetragonal zirconia polycrystal fixed dental prostheses produced using different multilayer techniques: split-file, over-pressing, and manually built-up veneers

    Science.gov (United States)

    Mahmood, Deyar Jallal Hadi; Linderoth, Ewa H; Wennerberg, Ann; Vult Von Steyern, Per

    2016-01-01

    Aim To investigate and compare the fracture strength and fracture mode in eleven groups of currently, the most commonly used multilayer three-unit all-ceramic yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) fixed dental prostheses (FDPs) with respect to the choice of core material, veneering material area, manufacturing technique, design of connectors, and radii of curvature of FDP cores. Materials and methods A total of 110 three-unit Y-TZP FDP cores with one intermediate pontic were made. The FDP cores in groups 1–7 were made with a split-file design, veneered with manually built-up porcelain, computer-aided design-on veneers, and over-pressed veneers. Groups 8–11 consisted of FDPs with a state-of-the-art design, veneered with manually built-up porcelain. All the FDP cores were subjected to simulated aging and finally loaded to fracture. Results There was a significant difference (Pveneering materials and techniques tested in the study, split-file, over-press, built-up porcelains, and glass–ceramics are, with a great safety margin, sufficient for clinical use both anteriorly and posteriorly. Analysis of the fracture pattern shows differences between the milled veneers and over-pressed or built-up veneers, where the milled ones show numerically more veneer cracks and the other groups only show complete connector fractures. PMID:26929667

  16. Effects of fly ash and boric acid on Y2O3-stabilized tetragonal ZrO2 dispersed with MgAl2O4: An experimental study on rat subcutaneous tissue.

    Science.gov (United States)

    Ergun, Gulfem; Guru, Metin; Egilmez, Ferhan; Cekic-Nagas, Isil; Yilmaz, Dervis

    2015-05-01

    The aim of this study was to evaluate the subcutaneous tissue reaction around zirconia-based materials. Forty-eight male Wistar Albino rats were used in this study. Disk-shaped (1mm height and 5mm diameter) samples composed of 67% spinel (MgAl2O4), 27% tetragonal zirconia polycrystal, 4% (m/m) fly ash and 2% (m/m) boric acid were inserted into dorsal muscles of rats. After 1, 4, 8 and 16 weeks, the animals were sacrificed and zirconia materials were removed with the surrounding tissue. Tissue sections were made with a microtome and then stained with hematoxylin and eosin. Sections were evaluated for the intensity of inflammation. Additionally, the somatic and visceral lymph nodes were evaluated. Data were submitted to one-way analysis of variance (ANOVA) and Tukey HSD tests at a significant level of p < 0.05. There were statistically significant differences between mean inflammatory scores in different experimental periods (p <0.05). In addition, the inflammatory reaction decreased over time. The tested materials had no damaging effect on the rat lymph nodes and did not have a toxic action on the internal organs. Therefore, zirconia polycrystal tested in the present study may offer a promising treatment alternative after further mechanical and biological studies are performed. Copyright © 2014 Elsevier GmbH. All rights reserved.

  17. Robert Bagley, Max Loehr and the Study of Chinese Bronzes, Ithaca, NY: Cornell East Asia Series, 2008, translated by Wang Haicheng, originally published in Chinese in Dushu, November 2010, 126-33.

    Directory of Open Access Journals (Sweden)

    Miao Zhe

    2011-12-01

    Full Text Available This essay reviews Robert Bagley’s intellectual portrait of Max Loehr, one of the founding fathers of the western study of Chinese art. Bagley’s book centers on the prolonged controversy between Loehr and Bernhard Karlgren over the history of ancient Chinese bronzes. Karlgren, an eminent philologist, tried to extract chronological information from a classification of décor motifs, an approach that he and many of his readers considered to be scientific and objective. Failing to detect any pattern of change in his material, he declared that all extant bronzes were made during two or three centuries of artistic stagnation, centuries that merely repeated designs invented in some earlier and more creative period that is unknown to us. Loehr by contrast succeeded in tracing a clear sequence of evolving styles in the same corpus of material. These positions were first staked out in the 1930s; most observers sided with Karlgren until the 1960s, when archaeology confirmed Loehr’s sequence. What makes the controversy interesting and instructive is that the right answer did not come from the approach that to this day strikes most readers as the scientific one, it came from a seemingly subjective and intuitive art-historical analysis. In part Bagley explains this unexpected outcome by showing that science as Karlgren conceived it—a rule-bound and mechanical procedure that excludes intuition and judgment—is a layman’s misconception; in essential ways, he shows, it was Loehr’s approach rather than Karlgren’s that was scientific. At a time when the prestige of the hard sciences continues to inspire attempts to import scientific methods into the humanities, Bagley has illuminating things to say about the real substance of those methods. He also has much to say about artistic invention and intentionality, and he clarifies one of art history’s most constantly used yet most ill-defined concepts, the concept of style, by arguing that it is not an

  18. Resistencia al desgaste de recubrimientos de bronce al aluminio producidos con técnica de proyección térmica//Wear resistance of aluminum bronze coatings produced by thermal spray

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    Dayan Carolina Cárdenas-Feria

    2015-09-01

    Full Text Available Se estudió la resistencia al desgaste adhesivo de recubrimientos de bronce al aluminio depositados con la técnica de proyección térmica por llama sobre bronce fosforado SAE 62. Los recubrimientos fueron fabricados variando las presiones parciales de los gases de combustión, oxígeno y acetileno. El material utilizado fue caracterizado estructuralmente mediante difracción de rayosX (X-ray diffraction, XRD y el estudio morfológico mediante microscopía electrónica de barrido (Scanning electron microscopy, SEM. La resistencia al desgaste adhesivo de los recubrimientos se determinó por medio del ensayo de bola sobre disco, utilizando como bola una esférica de acero 100Cr6. Los resultados obtenidos permiten establecer que los recubrimientos proyectados con una presión de oxigeno de 78 psi y una presión de acetileno de 8 psi presentan la mejor resistencia al desgaste en comparación a los tratamientos producidos. El modo de falla de desgaste en los recubrimientos producidos es discutido en esta investigación.Palabras clave: desgaste abrasivo y adhesivo,  proyección térmica,  recubrimientos.______________________________________________________________________________AbstractWe studied the adhesive wear resistance of aluminum bronze coatings deposited by thermal spray on phosphor bronze SAE 62 substrates. The coatings were deposited by varying the partial pressures of the combustion gases: oxygen and acetylene. The structural characterization was made through X-ray diffraction (XRD and the morphological analysis was performed by scanning electron microscopy (SEM. The adhesive wear resistance of the coatings was determined by the bole on disc test using a spherical ball made of steel 100Cr6 and with a diameter of 6 mm. The results obtained show that the coating projected with an oxygen pressure of 78 psi and an acetylene pressure of 8 psi have the better wear resistance compared with the substrate and the others treatments deposited

  19. Un nouvel habitat du Bronze final IIIb dans le Val d’Orléans et ses traces de métallurgie du fer : Bonnée, Les Terres à l’Est du Bourg (Centre, Loiret A new settlement from late Bronze IIIb in the val d’Orléans: Bonnée, Les Terres à l’Est du Bourg (lands to the east of the town (Centre, Loiret

    Directory of Open Access Journals (Sweden)

    Stéphane Joly

    2011-12-01

    Full Text Available La multiplication récente des diagnostics archéologiques autour du petit bourg actuel de Bonnée a permis la détection d’une occupation du Bronze final IIIb (circa 900-750 av. n.-e. sur environ un hectare aux Terres à l’Est du Bourg. Les limites inhérentes à ce type d’intervention réduisent l’interprétation des structures et toute approche spatiale de ce probable habitat repéré. L’étude conjointe des différents mobiliers en particulier céramique et métallurgique, mais aussi le torchis et la faune, atteste de sa culture matérielle et de son intérêt. Ces scories pourraient être parmi les plus anciennes traces en région Centre d’activité métallurgique du fer. Des activités de post-réduction sont avérées et certaines opérations de forgeage sont supposées.La découverte de cet habitat dans ce secteur du lit majeur de la Loire, apporte de nouvelles données concernant l’occupation du sol et ses problématiques évolutives dans le Val d’Orléans sur ces périodes de transition avec le Hallstatt ancien.The recent increase in the archaeological evaluations around the village of Bonnée has enabled the discovery of a final Bronze Age IIIb settlement (circa 900-750 BP on about a hectare of the Terres à l’Est du Bourg. The limits inherent in this type of work restrict the interpretation of structures and all spatial approaches to this likely dwelling. The joint study of the different furnishings, in particular ceramics and metal, but also the cob and fauna, attests to its material culture and its interest. The slag could be amongst the oldest iron metallurgy remains from the Centre region. Some activities of post-forging are proven and certain operations are guessed at. The discovery of this settlement in this sector of the major bed of the Loire, has produced new data concerning the occupation of the land and its evolutionary problems in the valley of Orleans over these periods of transition in the early

  20. Mechanically reliable thermoelectric (TE nanocomposites by dispersing and embedding TE-nanostructures inside a tetragonal ZrO2 matrix: the concept and experimental demonstration in graphene oxide–3YSZ system

    Directory of Open Access Journals (Sweden)

    Mehdi Estili

    2014-01-01

    Full Text Available Novel low-dimensional thermoelectric (TE materials suffer from poor mechanical reliability, which limits their applications, especially in mechanically harsh environments. Here, we propose a new concept, in which the novel, abundant, thermally stable TE-nanostructures are dispersed and then intimately embedded inside a protective, mechanically reliable tetragonal ZrO2 (TZP ceramic matrix with a low thermal conductivity. We also demonstrate an experimental proof-of-principle verification of our concept in reduced-graphene oxide (GO–3 mol% Y2O3–ZrO2 (3YSZ or 3Y-TZP nanocomposite system. TE characterizations suggest that our protective TZP matrix does not degrade the intrinsic TE property of the reduced GO network. These preliminary results are promising and encouraging to start research on similar TZP-matrix TE-nanocomposites, which contain more effective TE-nanostructures with larger intrinsic power factors. In this regard, we propose a scalable approach for fabrication of similar dense TE-nanocomposites composed of other one-dimensional and/or two-dimensional TE-nanostructures, which involves an aqueous colloidal approach and a subsequent spark plasma sintering. These new TZP-matrix TE-nanocomposites could be used for sustainable clean power generation, especially in mechanically harsh environments with thermal/mechanical shocks and vibrations, where energy availability, reliability and durability are more important than the energy efficiency. Considering the excellent biocompatibility of TZP matrix, they could even be used inside the body to power implanted medical devices.