bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Zinc on the Formation of Granules of Calcium Pyrophosphate
Authors: Masala Ombretta , O'Brien Paul 
Published: April 2011

ABSTRACTAccumulation of metals in inorganic granules is very common in invertebrates. The formation of metal deposits in both intra- and extracellular sites can be seen as a process for the detoxification of heavy metals. In barnacles, such inorganic granules usually contain calcium pyrophosphate. Incorporation of metals within such granules occurs mainly via the formation of metal pyrophosphate salts. In order to assess the chemistry of some reactions occurring during granule formation, the synthesis of calcium pyrophosphate, doped with zinc(II) ions with different [Zn]:[Ca] molar ratios, has been investigated at pH 7 and 25 °C. The thermal stability of the products was studied at different temperatures. Considerable variations occur in the structure of calcium pyrophosphate when zinc ions are present in solution in small concentrations.
Texturization Analysis by X-ray Diffraction of Shells of the MusselIschadium recurvum(Rafinesque, 1820) (Mollusca Bivalvia)
Authors: Gómez-Martínez Octavio , Aguilar Daniel H. , Alvarado-Gil Juan J. , Quintana Patricia , Aldana-Aranda Dalila 
Published: April 2011

ABSTRACTMost of the inorganic biomineralized materials are deposited on an organic matrix that controls the orientation and structure of the crystals. It is thought that chemical groups at the surface of the matrix may act as a template for the nucleation and growth of the mineral. A x-ray diffraction study of the texturization development of the bivalve mollusk shells is presented; specifically, the musselIschadium recurvum(Rafinesque, 1820), in different growing stages. The x-ray reflections show a preferred orientation that changes as the mollusk grows, and at the final stages only two crystallographic planes prevail.
Infrared Spectroscopy Characterization of Marine Shells
Authors: Gomez-Martinez Octavio , Aguilar Daniel H. , Quintana Patricia , Alvarado-Gil Juan J. , Aldana Dalila , Diaz-Flores Laura L. , Yañez-Limon Martin 
Published: April 2011

ABSTRACTFourier Transform infrared spectroscopy has been employed to study the shells of two kind of mollusks, American oysters (Crassostrea virginica) and mussels (Ischadium recurvum). It is shown that it is possible to distinguish the different calcium carbonate lattice vibrations in each case, mussel shells present aragonite vibration frequencies, and the oyster shells present those corresponding to calcite. The superposition, shift and broadening of the infrared bands are discussed. Changes in the vibration modes due to successive thermal treatments are also reported.
The Incorporation of Laser Ablation for Sampling into a Proton X-ray Emission System
Authors: Abraham Meg , Northover Peter , Grime Geoff 
Published: April 2011

ABSTRACTThe variation with depth of the composition of corrosion layers on buried metal objects can provide the archaeologist with valuable information relating to the burial conditions of the object. In some cases these layers can be very thick and so, normally destructive methods such as sampling are used to characterise the metal and corrosion layers when possible. We have developed a system for the use of a microfocused high power pulsed Nd:YAG laser to ablate the corrosion layer in a series of controlled steps while monitoring the composition of the exposed surface using focused PIXE and RBS in the external beam facility of the Oxford Scanning Proton Microprobe. With proper manipulation of the data we are able to calculate the values for trace elements at various depths in the corrosion layer. It is hoped that this system will lead to a better understanding of corrosion properties.
Extraction of Material from Oil Paints by Solvents
Authors: Erhardt David , Cunningham Roland H. , Räsänen Sirpa 
Published: April 2011

ABSTRACTDrying oils used to formulate oil paints consist primarily of polyunsaturated triglycerides, along with smaller amounts of mono- and diglycerides, free fatty acids, and other compounds such as sterols. The drying of oils occurs through an oxidative crosslinking process that also produces smaller scission products such as short chain fatty acids and diacids. Compounds that are not attached to the crosslinked oil matrix include glycerin, the unreactive free saturated fatty acids and their glycerides, soaps of fatty acids produced by reaction with metal ions from the pigment, and scission products. As the oil ages, additional soluble material is produced by hydrolysis of glyceride esters. These relatively low molecular weight compounds can be extracted by exposure to solvents, as occurs during the cleaning of paintings. Excessive extraction of material canembrittle the paint film and affect the appearance of the paint. This paper examines the types and amounts of compounds extracted from oil paint films as a function of solvent, exposure time, pigment, and age of the paint. The results indicate that solvents vary more in the speed that they extract material than in their selectivity. The composition of the extracts is consistent with predictions based on the mechanisms of the drying and aging processes. These results confirm the importance of using the least polar solvent possible to clean paintings and to formulate varnishes.
Some Metals of the Last Century
Authors: Goodway Martha 
Published: April 2011

ABSTRACTThe Twentieth Century can be looked back upon as a period in which a number of metal alloys unknown to previous centuries were introduced Some were alloys in unusual combinations of previously-used metals, but also elements little used earlier. Some of these alloys have already had their day and exist now only in museum collections, where they may also present problems of preservation. Many metals lost their traditional applications or added entirely new ones. Elements such as uranium and the semimetals that had been of interest only to the ceramist at the start of the century are now the bases of industries unforseen only a hundred years ago. From this it is concluded that predictions for the present century are uncertain.
Wrought Iron Wire from the Wheeling Suspension Bridge: a Metallurgical Assessment
Authors: Elban Wayne L. , Goodway Martha 
Published: April 2011

ABSTRACTThe Wheeling Suspension Bridge was constructed in 1849 over the Ohio River as a part of the National Road connecting the east coast with the interior of the United States. This was just before introduction of the Bessemer process opened the Age of Steel, so the wire for the suspension cables was manufactured from wrought iron by a local Wheeling firm. The Bridge is still standing and carries both pedestrian and vehicular traffic. Samples of wire from the suspension cables were provided courtesy of Prof. Emory L. Kemp of West Virginia University, and were examined metallurgically by optical microscopy and with a scanning electron microscope for features such as inclusions, grain size, and morphology. Hardness was measured as a proxy for strength. The combined results are compared with earlier observations made of wire of finer gauge drawn for historical musical instruments.
Egyptian Faience Inlay Techniques: a process for obtaining detail and clarity by refiring
Authors: Riccardelli Carolyn , Mass Jennifer , Thornton Jonathan 
Published: April 2011

ABSTRACTThe faience of the New Kingdom period is frequently decorated with an expanded palette of red, black, and yellow. This polychrome decoration was often accomplished by inlaying one color of paste into another. The aesthetic success of these inlay techniques reveals a fundamental understanding of the materials' characteristics before, during, and after firing, and knowledge of how to manipulate these characteristics. The goal of this research is to more fully understand ancient Egyptian faience inlay techniques by characterizing the properties of a set of standard reproductions. As the most aesthetically successful reproductions were obtained using pre-fired components, a series of experiments was performed to quantify changes in glaze color, glaze gloss, and depth of glaze penetration upon refiring. Data was gathered from replicated samples and cross-sections using SEM, UV-VIS spectrophotometry, colorimetry, and optical microscopy. Visual comparisons were made between cross-sections of replicated inlays and examples of broken ancient Egyptian faience inlays.
Core Vessel Technology: A New Model
Authors: Giberson Dudley F. 
Published: April 2011

ABSTRACTAncient Egyptian XVIII Dynasty core vessel manufacturing technology had many sequential steps to make a core vessel, but there were only three essential elements to the process. One, the base layer of glass was applied as a fritted powder; two, the objects were manufactured over a vertical heat source; and three, the vessels were made in very low temperatures (maximum of about 800°
Hydration and Crystallization Pressure of Sodium Sulfate: a Critical Review
Authors: Flatt Robert J. , Scherer George W. 
Published: April 2011

ABSTRACTThe two most frequently mentioned mechanisms used to explain the severe damage that occurs when a porous material, containing the anhydride phase of sodium sulfate, is exposed to either water or rising humidity are critically reviewed. Both derivations are presented along with their underlying hypotheses. Critical differences are discussed and it is concluded that crystallization pressure is the relevant mechanism. In effect however, it is shown that the expressions obtained both for crystallization pressure and hydration pressure are quite similar.
Hygric Swelling of Portland Brownstone
Authors: Gonzalez Inmaculada Jimenez , Higgins Megan , Scherer George W. 
Published: April 2011

ABSTRACTPortland Brownstone (PB) is a widely used building material, particularly in New York City, that is susceptible to severe deterioration from weathering. This stone contains clays that may cause damage by dilating during wetting/drying cycles. We have measured the swelling strain of PB in aqueous solutions to determine the effect of ionic strength (of KCl and CaCl2) and water activity (in isopropanol solutions). We have also measured the stress exerted during swelling when the expansion is constrained. These data permit calculation of the stresses produced during wetting/drying cycles, which are found to be comparable to the tensile strength of the stone.
Design and evaluation of restoration mortars for historic masonry using traditional materials and production techniques
Authors: Moropoulou Antonia , Bakolas Asterios , Moundoulas Petros , Aggelakopoulou Eleni , Anagnostopoulou Sofia 
Published: April 2011

ABSTRACTCement based mortars used for historic masonry restoration presented unsatisfactory results, due to their chemical and physico-mechanical incompatibility to original buildings. In the present research, several syntheses of restoration mortars are produced using traditional techniques and materials such as binders (aerial and natural hydraulic lime), pozzolanicadditives (natural and artificial pozzolanas) and aggregates (sand and crushed brick). The technical characteristics of the mortars were determined using mechanical tests (compressive and flexural) and mercury intrusion porosimetry measurements at the time of 1, 3, 9, 15 months of curing. Water absorption measurements were performed at the time of 9 and 15 months curing, in order to evaluate mortars microstructural characteristics, their rate of water absorption and the total percentage of absorbed water. The aerial lime - artificial pozzolana mortar presented the best mechanical and microstructural performance. Hydraulic mortars acquired the maximum of the mechanical strength in 1 month, lime - pozzolana mortars in 3 months while aerial lime mortars continue to gain mechanical strength even in 15 months curing. Furthermore, the use of ceramic aggregates produces lightweight and elastic mortars, compatible to historicones.
Batch Material Processing and Glassmaking Technology of 9th Century B.C. Artifacts Excavated from the Site of Hasanlu, Northwest Iran
Authors: Stapleton Colleen P. , Swanson Samuel S. 
Published: April 2011

ABSTRACTThe site of Hasanlu is located southwest of Lake Urmia (Lake Rezaiyeh) in the province of Western Azerbaijan, northwest Iran. Excavations carried out by Dr. R. H. Dyson, Jr. of the University of Pennsylvania from 1957 to 1977 of the Iron Age levels at Hasanlu yielded a large number of glass beads, as well as glass vessels, and glass furniture inlays or wall fittings. Sampling of many of these pieces was limited to weathered areas, requiring the use of a micro-analytical technique to characterize the glass. Electron microprobe and wavelength dispersive analysis were used to characterize the chemical compositions of the glasses of Hasanlu. The glasses are soda-lime-silica in composition, containing about 17-21 wt% soda and 2-8 wt% lime. of 51 glasses analyzed to date, 47 contain about 1-6 wt% of magnesia and 1-4 wt% potash, indicative of a plant ash source of alkali. Four glasses contain less than 1 wt% each of magnesia and potash, suggesting that these may have been made with a mineral alkali source like natron.At least 35 glasses contain inclusions of partly reacted batch materials. In blue transparent to translucent, black translucent, and yellow opaque glasses, large, 0.2 mm diameter, droplets of alkali sulfates exhibit features that indicate they were an immiscible liquid coexisting with a surrounding silicate liquid. These sulfate droplets, which appear to be relatively common in the glasses found at Hasanlu, are probably the scum or “gall” that can form during melting of poorly prepared plant ash. Remnants of original raw colorants occur in a few glasses. Many of the black glasses contain polymetallic sulfides of different combinations of lead, copper, antimony, and iron. These inclusions and the glass chemistry are used to interpret the origin and processing of the batch materials, and the conditions under which the materials were melted.
Dressing Technology for the Silver Ore in “Iwami” Silver Mine Site, Japan
Authors: Murakami Ryu , Takada Jun , Torigoe Toshiyuki , Matsumoto Iwao , Toya Yoshio , Morioka Shouji , Oguni Haruo , Endou Hiromi , Nakada Ken-ichi 
Published: April 2011

ABSTRACTIn the early modern age Japan was a kingdom rich in metal resources. A lot of gold, silver and copper were produced and exported to foreign countries, nevertheless Japan maintained a national isolation policy. The Iwami silver mine located in Shimane prefecture was the representative silver mine that prospered most. It produced about 10 % of the world's silver output. It is now mostly abandoned and reduced to ruins. Only a famous picture scroll remains to indicate its real activities. Through archaeological excavation started in 1983, it is becoming clear that extensive remains of mining and smelting are preserved. From 1996 scientific investigation of the excavated remains has been conducted. During excavation, and confirmed by scientific research, we recognized that the artifacts deposited during both the mining of the silver ore and the smelting process could be classified into two artifactual types; objects and fragments produced in the dressing process that were not influenced by a heating process and objects influenced by a heating process and produced by smelting and refining. The low grade ore, waste and tailings (remains after gravity concentration) that were scrapped in the dressing process are included in the former type, and the furnace fragments for smelting and refining, tuyeres (blast pipes) and slag and other smelter remains are of the latter type. The waste and tailings scrapped in the dressing process have not previously been studied. This study aimed at systematically investigating the dressing technology and estimating the ore grade through the evaluation of the range of variation in the waste and tailings left as scrap in the dressing process. The analytical results revealed the actual activities practiced at the Iwami silver mine in the dressing process.
Study on the Green Glaze from Qionglai Kiln Site in Sichuan: One of the Earliest Phase-Separated Opaque Glazes in China
Authors: Li Weidong , Wu Jun , Li Jiazhi , Guo Jingkun 
Published: April 2011

ABSTRACTThe Qionglai kiln site is a famous folk kiln site in Sichuan province, China, of the Tang dynasty (618-907 A.D.). The wares from Qionglai kiln site bear a unique national style and striking local features. A series of opaque green-glazed shards with mild gloss and jade-like feel, excavated from Shifangtang kiln site were selected as test samples. The glaze and body compositions and microstructures of the shards were studied by means of EDXRF, FESEM and DTEM/SAD/EDS. The study has demonstrated that the opaque green glazes from Qionglai kiln site are high-temperature calcia-magnesia-silicate glazes and that typical phase-separated glazes of the droplet structure. The isolated droplets are rich in SiO2 and the matrix is rich in oxides of Ca, Mg, P, Ti and Fe. We have shown that Al2O3 suppresses phase separation. The droplet diameter falls in the range of 0.1-0.4 –m, causing intensive light scattering, and resulting in good opacification and jade-like texture. The green Glaze from Qionglai Kiln Site is one of the earliest phase-separated opaque glazes in China. The study also shows that there is a close relationship of compositions between Qionglai kiln and Changsha kiln.
Experimental investigation of silvering in late Roman coinage
Authors: Vlachou C. , McDonnell J.G. , Janaway R.C. 
Published: April 2011

ABSTRACTRoman Coinage suffered from severe debasement during the 3rdcentury AD. By 250 AD., the production of complex copper alloy (Cu-Sn-Pb-Ag) coins with a silvered surface, became common practice. The same method continued to be applied during the 4thcentury AD for the production of a new denomination introduced by Diocletian in 293/4 AD. Previous analyses of these coins did not solve key technological issues and in particular, the silvering process. The British Museum kindly allowed further research at Bradford to examine coins from Cope's Archive in more detail, utilizing XRF, SEM-EDS metallography, LA-ICP-MS and EPMA. Metallographic and SEM examination of 128 coins, revealed that the silver layer was very difficult to trace because its thickness was a few microns and in some cases it was present under the corrosion layer. Results derived from the LA-ICP-MS and EPMA analyses have demonstrated, for the first time, the presence of Hg in the surface layers of these coins. A review of ancient sources and historic literature indicated possible methods which might have been used for the production of the plating. A programme of plating experiments was undertaken to examine a number of variables in the process, such as amalgam preparation, and heating cycles. Results from the experimental work are presented.
A New X-Ray Scattering Method for Determining Pore-Size Distribution in Low-k Thin Films
Authors: Omote Kazuhiko , Kawamura Shigeru 
Published: April 2011

ABSTRACTWe have successively developed a new x-ray scattering technique for a non-destructive determination of pore-size distributions in porous low-κ thin films formed on thick substrates. The pore size distribution in a film is derived from x-ray diffuse scattering data, which are measured using offset θ/2θ scans to avoid strong specular reflections from the film surface and its substrate. Γ-distribution mode for the pores in the film is used in the calculation. The average diameter and the dispersion parameter of the Γ-distribution function are varied and refined by computer so that the calculated scattering pattern best matches to the experimental pattern. The technique has been used to analyze porous methyl silsesquioxane (MSQ) films. The pore size distributions determined by the x-ray scattering technique agree with that of the commonly used gas adsorption technique. The x-ray technique has been also used successfully determine small pores less than one nanometer in diameter, which is well below the lowest limit of the gas adsorption technique.
Properties of Sputtered Bilayer WNx/W Diffusion Barriers between Si and Cu
Authors: Leedy K. D. , O'Keefe M. J. , Dahlgren E. J. , Grant J. T. 
Published: April 2011

ABSTRACTCopper interconnect metallizations in next generation integrated circuits will require thin diffusion barrier layers (<20 nm) between the Cu and low-k dielectric which may also function as seed layers for subsequent material depositions. One possible structure entails a multicomponent diffusion barrier with a lower resistivity component, such as W on WNx. In this study, sputtered WNx/W bilayer thin films were investigated as diffusion barriers between Si and Cu. The total thickness of the WNx/W bilayer was fixed at 20 nm while the WNx thickness was varied from 0 to 20 nm. After deposition of the barrier films, a 100 nm thick Cu film was sputtered over the top of the á-W and amorphous WNx bilayer. The as-deposited WNx/W film stress was found to be strongly dependent on the relative amount of WNx and W present and the addition of a Cu overlayer was found to mitigate the stress levels. The WNx/W barriers remained stable after 650°C anneals and exhibited phase transformations to W2N. Microstructural characterization using transmission electron microscopy and x-ray diffraction and chemical analysis by x-ray photoelectron spectroscopy of the films were used to identify the as-deposited and transformed phases.
Understanding the Morphologies and Polymerization Mechanism of Homopolymer and Block Copolymer Brushes by Living Anionic Surface Initiated Polymerization
Authors: Park Mi-Kyoung , Sakellariou George , Pispas Stergios , Hadjichristides Nikos , Mays Jimmy , Advincula Rigoberto 
Published: April 2011

ABSTRACTHomopolymer and block copolymer brushes grafted from Au and Si (SiOx) surfaces via living anionic surface initiated polymerization (LASIP) has been reported. 1,1-diphenylethylene (DPE) derivative, an initiator for anionic polymerization, was grafted onto planar Si-wafer and Au surfaces by self-assembled monolayer (SAM) techniques. n-BuLi was used to activate the DPE for anionic polymerization of monomers at the interface under high vacuum. By a careful sequence of monomer introduction, reaction, and termination, homopolymer and block copolymer tethered polymer brushes were obtained. The importance of initiator activation, control of polymerization conditions, and removal of excess BuLi is emphasized. Interesting differences in morphology, thickness, grafting density, and polymerization conditions contrasts LASIP from solution and other surface initiated polymerization (SIP) mechanisms. The formation of block copolymer sequences highlights the unique utility of a living anionic polymerization technique on surfaces.