bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties and Microstructure of Mullite-Glass Ceramics for Multilayer Ceramic Substrates
Authors: Ushifusa N. , Sakamoto K. , Ogihara S. , Fujita T. 
Published: March 2011

AbstractMullite (3Al2O3·2SiO2) has a low thermal expansion coefficient and a low dielectric constant making it a favorable material for substrate applications. Sintering of pure mullite ceramics is difficult, however, even above 1700°C. Thus, mullite-glass ceramics containing glass additives (Al2O3-MgO-SiO2 glass) which could be sintered at about 1600°;C were fabricated and their properties were investigated. The ternary system diagram of Al2O3-MgO-SiO2 shows that high SiO2 content glass depos its cristobalite at 200 to 270°C, which causes a substantial volume change, resulting in ceramic substrate cracking. Therefore it is particularly important to prevent crystallization of cristobalite from the glass phase in mullite-glass ceramics. The glass phase softens or partially fuses above 1600°C, and cristobalite formation in the glass phase occurs in the cooling process during firing. In order to obtain good substrates of mullite-glass ceramics, a higher temperature for sintering and faster cooling rate after firing are preferable. Analytical results by X-ray, SEM and EPMA show that mullite dissolves in the glass phase at a higher sintering temperature and more mullite crystallizes in the cooling process with a lower rate. The content of Al2O3 in the glass phase, therefore, increases with the increased sintering temperature and cooling rate, which may restrain crystallization of cristobalite. By adjusting of the composition of mullite and glass phase, mullite-glass ceramics with low dielectric constant (5.9), thermal expansion coefficient (3.5×10−6/°C) close to that of silicon chips, and high bending strength (210MPa) have been developed. These substrates made of mullite-glass ceramics are suitable for mounting silicon devices of computer processors.
Passive Polymeric Waveguide Materials for Optical Interconnects
Authors: Hutcheson Lynn D. , Arrington John P. , Powell Stephen F. 
Published: March 2011

AbstractThe need for higher bandwidth interconnect schemes to relieve the communications bottleneck caused by the ever increasing speeds of discreet electronic devices has led to a renewed interest in thin film optical waveguides as interconnect media. This paper reviews some of the polymeric materials that have been investigated for use as thin film passive optical waveguides over the past ten years. Several proposed applications for these waveguides are presented and the specific material requirements of these applications are discussed. The strengths and weaknesses of specific polymeric materials are considered in view of these requirements. While reference is made to a variety of polymers that have been considered for these applications, emphasis is placed on the relative merits of polyimide and acrylate polymer based systems.
New Patternable Materials for Electronic Packaging
Authors: Popall Michael , Kappel Jürgen , Pilz Monika , Schulz Jochen 
Published: March 2011

AbstractNew inorganic-organic copolymers (ORMOCERs – ORganically MOdified CERamics) were developed as protective coatings for electronic and optical devices, as patternable insulation and passivation layers for electronics, e. g. MCM's, and as possible interconnects and waveguides for micro optics.Depending on the chemical composition and the processing parameters, their important features are low permittivity constants (eR ≤ 3.2), high bulk resistance (RD > 1016 Ωcm), high dielectric strength (ED ≤ 400 V/μm), refractive index around 1.48, optical transparency in the range of 400 – 1300 nm, and good adhesion to numerous substrates, such as Al2O3, glass, silicon, copper, aluminum, steel, polyimides, polyesters and epoxides.The materials can be applied using standard technology. They are patterned by laser direct writing, photolithographic, screen printing or embossing technologies.
Process Dependence of Microstructure and Properties of Sintered Aluminum Nitride for Electronic Packaging
Authors: Dutta I. , Mitra S. , Cooper J. 
Published: March 2011

AbstractThe development of secondary phases due to additions of Y2O3 during sintering of aluminum nitride was studied. Depending on the heat treatment conditions and the amount of Y2O3 added, different proportions of AlYO3, Al5Y3O12 and Al2Y4O9 were found at the grain boundaries. Temperatures ≳1850°C also resulted in loss of Y2O3 and/or Y-aluminate, yielding some γAl2O3. The mechanical properties and the thermal conductivity of the sintered product were observed to be dependent on the grain boundary phase constitution and hence the specific heat treatment condition.
Enhancing the Interfacial Bond Strength of Lignocellulosic Fiber Dispersed in Synthetic Polymer Matrices
Authors: Simonsen John , Rials Tim 
Published: March 2011

AbstractWood-plastic composites have been produced utilizing a phenol-formaldehyde pretreatment of the wood. The use of additives to cross link the plastics and increase the interfacial bond between the wood and plastic were also investigated. These preliminary results suggest that pretreatment of the wood with a thermosetting resin may increase the stiffness of the composite. The use of an octylphenol as a plastic compatabilizer did not reliably increase stiffness in this system, although additional study is warranted. An interaction between the wood and the polystyrene in the plastic mixture may be indicated.
Recycling Lignin for Engineering Applications
Authors: Feldman D. , Banu D. , Lacasse M. , Wang J. 
Published: March 2011

AbstractLignin, a complex natural polymer produced by all vascular terrestrial plants is second in abundance only to cellulose and is the matrix holding plant fibres together. Lignins are recovered mainly as byproducts from woodpulping processes with about 100 million tons produced annually worldwide.Large volume uses for lignin byproduct other than for generation of energy (kraft process) are most likely to be in materials applications.In the last decades many studies aimed to the recycling of different lignins (sulfite, kraft, organosolv, steam exploded, hydrolytic, etc.) in polymeric systems based on thermoplastics, thermosettings, elastomers, adhesives, sealants, etc.Among all the technical lignins, sulfate lignins are chemically the most reactive and are therefore used to modify polymers. The oldest and the most familiar application of lignin as a component of polymeric materials involves the reinforcement of rubber. Multicomponent materials can be created by combination with other macromolecules like polyethylene, polypropylene, or poly(vinyl alcohol) to produce polyblends, block copolymers or interpenetrating polymer networks.The present communication will try to present such examples of polymeric systems based on recycled lignin, and synthetic polymers such as: polyurethane, epoxy, acrylics, silicones.
Structural Changes in Cellulose During Papermaking and Recycling
Authors: Atalla Rajai H. 
Published: March 2011

AbstractRecent advances in understanding the structure of cellulose are used as the basis for analyzing the structural changes that occur in pulp fibers during papermaking, particularly in the drying stage. These changes are responsible for the degradation of papermaking properties, and they must be reversed during recycling if the maximum papermaking potential of the virgin fibers is to be recovered. A number of studies have assessed the structural transformations that can occur in cellulosic fibers upon exposure to elevated temperatures. The researchers have invariably observed that the changes occur at the secondary and tertiary levels of structure, the levels that can have significant effects on the properties of fibers. In addition, some studies have focused specifically on the structural effects of recycling; clear correlations of structural change with changes in paper characteristics have been reported. The results of the various studies point to directions for further investigations into enhancing the recovery of papermaking value from recycled fibers.
Recycling of Paper and Bulk Properties of Recycled Fiber
Authors: Silveri Luigi 
Published: March 2011

AbstractThere are several clear trends in the recycling of paper. Firstly, the amount of recycle is increasing and will continue to do so. Secondly, recycled fiber is being used in greater quantities. Finally the recycled fiber is being introduced into higher quality paper grades which previously did not have any recycled content.This means that on the one hand the quality of the recycled furnish is deteriorating in terms of contaminant level and strength, while on the other hand there is an increased expectation in terms of properties of the end product, the recycled fiber.The major unit operations of recycling and general principles of system design are reviewed, methods for enhancing these properties and limits which can be achieved are discussed.
Recycling Bleach Technologies
Authors: Minor James L. 
Published: March 2011

AbstractWhen faced with bleaching recycled fibers, the technologist must consider the usual factors associated with the bleaching of virgin fibers plus additional factors introduced by recycling. The lignin content of the furnish and the products to be made determine whether delignifying or lignin-preserving agents are to be used. Factors introduced by recycling include mixed lignin contents, dyes, residual ink particles and carrier chemicals, contaminants, color reversion, and hornification (which affects accessibility of chromophores to bleaching reagents). In addition, the technologist must be concerned with the environmental impact of the bleaching operation.Dithionite and formamidine sulfinic acid are effective lignin-preserving reductive bleaching agents for recycled fibers. Hydrogen peroxide is an effective lignin-preserving oxidative agent, but heavy metals and enzymes catalyze its decomposition. Chelating agents have an important role in decreasing metal content. For some delignification and effective removal of organic chromophores, oxygen and ozone show promise. Research on the use of oxygen-based oxidative bleaching agents is intense because of their favorable environmental attributes.
Filler Pigments Designed for Recyclability
Authors: Passaretti June D. , Young Trudy D. , Herman Mick J. , Evans D. Bruce 
Published: March 2011

AbstractThis paper discusses the use of a new rhombohedral precipitated calcium carbonate (PCC) morphology and existing PCC morphologies in wood free, wood containing, and recycled paper. The new material has properties that mimic TiO2 with respect to morphology, particle size, particle size distribution, and surface area. TiO2 is widely used by the paper industry as a functional filler for opacity and brightness. The new PCC rhombohedral morphology can be used in place of TiO2 for many applications greatly reducing the cost of production.The physical properties of the new PCC morphology as well as application as a paper filling pigment will be discussed.
Estimation of Fiber-Matrix Interfacial Shear Strengths in Lignocellulosic-Thermoplastic Composites
Authors: Sanadi A. R. , Rowell R. M. , Young R. A. 
Published: March 2011

AbstractThe interaction and adhesion between fibers and the matrix in composite materials have a significant influence on the properties of the fiber composite. It is, therefore, of utmost importance to be able to evaluate the properties of the interface/ interphase of the fiber-matrix for optimization of the properties of the composites. Techniques that are currently used to evaluate the properties of this region will be discussed with special attention to lignocellulosicthermoplastic composites. Sample preparation, applicability, problems and advantages of each technique will be highlighted. Results obtained at our laboratory for wood-low molecular weight polyethylene systems using the pull-out test will be discussed.
The National Gallery at War
Authors: Saunders David 
Published: March 2011

ABSTRACTWith the outbreak of the First World War in 1914, Britain found herself involved in a European war for the first time in nearly a century. The National Gallery had thus been immune to the possibility of attack by hostile forces, although it is interesting to note that when war was declared, the Gallery had only recently reopened to the public following an attack on a Bellini by a suffragette.
Evaluation of the Effectiveness and the Potential Damage of Cleaning Methods for the Restoration of Stained Glass Windows
Authors: RÖMICH Hannelore , Fuchs Dieter R. 
Published: March 2011

ABSTRACTA comparative study on the effects of restorational cleaning methods for stained glass windows was carried out using corrosion sensitive model glasses. Typical deterioration phenomena like crusting, leaching and microcracking could be simulated using accelerated weathering in climatic test cabinets. The sensibilization of such samples caused by cleaning was assessed by infrared spectroscopy and light microscopy after re-weathering.
Status Report: Assessment of Cultural Losses Suffered by American Aleuts During World War II
Authors: Smith Barbara Sweetland 
Published: March 2011

ABSTRACTIn 1988, the U. S. Congress provided $1.4 million to six Aleut communities in Alaska as restitution for damage done to their churches by U. S. forces stationed in the Aleutians during World War II. The residents of these communities had been forcibly evacuated and interned for up to three years in camps in southeast Alaska where many died. At the request of the Aleuts, restitution to the Orthodox churches was given a special place in the U. S. decision to make reparations. The Aleutian/Pribilof Islands Association, a non-profit organization, has been charged by Congress with assessing the damage and estimating the cost of restoration. The assessment project, begun in November 1991, has utilized the expertise of an architect and art conservator to examine structures and church furnishings of these churches and has reached some preliminary conclusions: 1) The stress of travel for those icons and liturgical vessels which accompanied the evacuees was significant and damage related to that travel is evident today; 2) The churches themselves were often targets of vandalism and looting by the American troops; 3) the churches were left without regular maintenance in the harsh climate of the Aleutians for three years; 4) the Aleuts were destitute on their return and could not restore the buildings to their former condition; 5) the results of makeshift repairs in the immediate post-war era are evident today in a general state of deterioriation. The final report to Congress on this project is due in the Spring 1993.
Understanding Art Through Technical Analysis Inferences From Pigment Identification
Authors: Berrie Barbara H. 
Published: March 2011

ABSTRACTPigment identification and technical analysis of works of art provide the historian and conservator with information that allows a new view of an object. The methods the analyst chooses depends on the nature of the sample and the materials and method expected for the age of the object being examined. Several analytical methods are used frequently in the museum field with great success; these include x-ray fluorescence spectroscopy, x-ray powder diffraction methods and optical microscopy. Results from the analysis of pigments in paintings by Derain, Beckmann, El Greco, G. David, and Gentileschi are given. The results include discovery of an unpublished formulation of cobalt violet, example of the use of particle size to change the appearance of color, and the use of x-ray fluorescence to determine artists' palettes without removing samples from the works of art. The study of the El Greco and the Gentileschi show how technical investigations can complement art historical research.
Non-Destructive Spectroscopic Investigations on Paintings Using Optical Fibers
Authors: Bacci M. , Baronti S. , Casini A. , Lotti F. , Picollo M. , Casazza O. 
Published: March 2011

ABSTRACTThe main objective of our research is the development of totally non-destructive methodologies for the investigation of art works. We propose the use of fiber optic reflectance spectroscopy (FORS) in the visible and near-infrared region as a tool for the identification of the pigments used in painting. We have considered several representative inorganic artists' pigments (mainly till the Renaissance period); powder X-ray diffractograms and diffuse reflectance spectra in the visible, near-, middle- and far-infrared range were recorded for pure pigments. Then we prepared suitable samples with the same pigments using fresco, tempera and oil techniques. The visible and near-infrared spectra of these samples were recorded using an optical fiber spectrum analyzer; color analysis (chromaticity, dominant wavelength and purity) was also performed. The obtained results were used in the interpretation of the spectra obtained from some paintings collected in the Uffizi Gallery, Florence (Giotto and Luca Signorelli). The pointwise information obtained by FORS analysis was also used to calibrate and tune an image spectroscopy system, based on sequences of band-pass filtered images in the near infrared range.
Application of Surface and Bulk Analytical Techniques for the Study of Iron Metallurgy Slags at Tell Afis (N-W Syria)
Authors: Ingo G.M. , Scoppio L. , Mazzoni S. , Mattogno G. , Scandurra A. 
Published: March 2011

ABSTRACTBy a combined use of small area X-ray photoelectron spectroscopy (SA-XPS),X-ray induced Auger electron spectroscopy (XAES), scanning electron microscopy (SEM) and electron probe for microanalysis (EPMA), the microchemistry of a group of slags from Tell Afis (North-Western Syria), dating back to Iron Age II (750 B.C.), have investigated. The results show and localize the presence of different iron oxides and hydroxides as well of various glassy and crystalline silicates, whose chemical structure and morphology have determined.
The Protection of National Treasures at the British Museum During the First and Second World Wars
Authors: Caygill Marjorie L. 
Published: March 2011

ABSTRACTWith the emergence in the 20th century of long-range methods of destruction, museums and galleries have had to develop appropriate measures to protect their collections. The British Museum first took such measures on site in 1914 and followed this by evacuating some of its most valuable objects in 1918. Similar procedures were followed in the Second World War and, despite major damage to the building, no significant items (apart from books) were lost.
Investigation of Decorative Coating on Kongo Ceramics Using U. V. Light and Ftir Analysis
Authors: Hexter Madeleine R. , Hopwood Walter R. 
Published: March 2011

ABSTRACTThe ethnographic and art historical literature reports the use of vegetable resins on Central African ceramics, specifically those made by the Kongo peoples. The purpose of this investigation was to develop a procedure for determining the nature of decorative coatings generally on African ceramics. The investigation focused on a group of Kongo ceramics. FTIR spectra of known resins were obtained and compared with several samples taken from Kongo ceramics. The ceramics were also examined under U.V. light. This paper discusses the results of the examinations and analysis.
Protection of Archival Record From Pollutants the Diffusion of SO2 Through Archival Boxboard
Authors: Guttman Charles M. , Jewett Kenneth L. 
Published: March 2011

ABSTRACTThe diffusion constants of sulfur dioxide in boxboards, commonly used to store archival documents, have been measured. For the most common boxes used by National Archives and Record Administration a diffusion constant of about 0.001 cm2 / sec was determined independent of gas concentration. These results are discussed in terms of a model of the microenvironment provided by these boxboards as used in archival storage.
Further Study of the Process of Technological Evolution of Ancient Chinese Pottery and Porcelain
Authors: Jiazhi Li , Hongjie Luo , Liming Gao 
Published: March 2011

ABSTRACTThe chemical compositions and firing temperatures of seventy-four stamped pottery and proto-porcelain fragments which were excavated from Jiangxi, Zhejiang, Henan and Fujian were studied. Their chemical compositions, together with a database of more than 600 pottery and porcelain bodies and 100 protoporcelain and porcelain glazes previously investigated, were processed and evaluated by correspondence analysis. Their firing temperatures and those of more than 200 pottery and porcelain samples were compared as well. The results of this investigation yield a more objective and comprehensive view of the process of technological evolution of ancient Chinese pottery and porcelain than heretofore possible. The place of stamped pottery and proto-porcelain in the evolution process is better understood, and the differences between the patterns of continuity and change in the north and the south of China is further discussed in this paper.
Cleaning with Laser Radiation on Istria Stone
Authors: Maravelaki Pagona , Biscontin G. , Zendri E. , Polloni R. , Cecchetti W. 
Published: March 2011

ABSTRACTCleaning treatments necessary for stone conservation consist of removing compounds that were superimposed on the original material by means of physico-chemical processes.,The purpose of this work is to identify the transformation of stone surface by the LASER treatment. Cleaning test on Istria stone with LASER radiation at different energies and in different regimes have been performed. The depletion of the original material has been evaluated by means of SEM microprobe analyses.
Intercalated Two-Dimensional Ceramic Nanocomposites
Authors: Giannelis E.P. , Mehrotra V. , Tse O. , Vaia R.A. , Sung T.-C. 
Published: March 2011

ABSTRACTNew generations of polymer-ceramic nanocomposites are being developed by intercalation of layered solids. Synthetic approaches include intercalative polymerization, direct polymer intercalation and molecular dispersion of the host layers in the polymer matrix. The unique physical and mechanical properties of the hybrids are attributed to the molecular dispersion and the synergism between the individual components.
Mass Spectrometric Study of ECR Microwave Plasma Etching of Si3N4 Films
Authors: Jin Ming , Kao Kwan C. 
Published: March 2011

ABSTRACTThe effects of ion impinging energy on the etching of Si3N4 films in an electron cyclotron resonance (ECR) microwave plasma etching system have been studied. An alternating frequency (10 MHz) bias voltage was used to control the ion impinging energy. The experimental results show that the etching rate in the initial period (less than 3 min) of the etching process is noticeably lower than that in the following period for bias voltage Va > 10 V. The length of the initial period depends on the plasma density. The etching rate in the following period depends on the bias voltage. But the above dependence disappears for Va < 10V. It is found that the surface oxide contribution to the bias effects is negligible. The mass spectrometric measurement of the transient of the etching product SiF4 confirms these bias effects. The effects may be attributed to the ion radiation damage to the subregion lattice even at low ion energies.
Some Properties of Ultra Thin Oxides Grown in Afterglow Oxygen Plasma
Authors: Chen P. C. , Lin J. Y. , Hsu Y. J. , Hwang H. L. 
Published: March 2011

ABSTRACTMicrowave remote plasma oxidation were used to study the oxidation of Si and SiGe samples at a lower temperature. C–V measurements were performed to investigate the trap density, and the corresponding bonding structures of thin oxide were revealed by FTIR analysis. SIMS depth profiles were used to reveal the extent of the Ge segregation in SiGe samples. The system can grow ultra thin SiO2 with lower effective trap density. And Ge segregation can be largely suppressed by atomic oxygen oxidation at a lower temperature.