bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conservation of the Windover (8Br246) Textiles
Authors: Humphrey Bruce , Gardner J.S. , Andrews R.L. , Adovasio J.M. , Strong D.E. 
Published: March 2011

AbstractThe excavations at the Windover Bog site (8BR246) in 1986 and 1987 yielded 87 specimens of technologically sophisticated textiles and other perishables from 37 human burials. The assemblage currently represents the oldest known textiles from this hemisphere. Unfortunately, microscopic examination has demonstrated that substantial cellular degradation has occurred in these artifacts. In fact, these items are but the dimmest reflections or more accurately skeletons of their former predepositional states. Although traditional consolidants ensured a minimum of warpage and shrinkage with subsequent freeze drying, they produced an undesirable surficial film. Additionally, the resultant products were extremely brittle and required further treatment. To this end, several leading authorities suggested the testing of Parylene gas phase polymer technology on the Windover specimens. The senior author introduced Parylene gas phase technology to the conservation field in 1984. Since that time, numerous evaluation programs have been undertaken at major institutions. Important artifacts as well as extremely ancient natural history materials have been successfully treated utilizing Parylene technology [1]. This paper specifically addresses the application of Parylene gas phase polymer technology to the consolidation and preservation of the unique textile materials recovered from the Windover site. Major areas of discussion are: historical background, early conservation efforts, evaluation and decision to use Parylene technology, properties of the Parylene family of polymers, the method of deposition and treatment, and final conclusions on the consolidation of the treated textiles.
Permanence of Washi(Japanese Paper) (Part II)
Authors: Inaba Masamitsu , Sugisita Ryuitiro 
Published: March 2011

AbstractThe change of degree of polymerization (DP), crystallinity and extent of oxidation during deterioration of Washi (Japanese paper) were studied. The extent of decrease of DP of cellulose in the Washi samples correlated with their acidity. The higher DP of cellulose in Washi fiber compared to that in wood fibers contributes to its permanency. It is reported that partial recrystallization of the amorphous regions in fibers during ageing results in a decrease of flexibility of the paper. From measurements of X-ray diffraction, less recrystallization of Kozo, Mitsumata and Gampi papers occurs during ageing treatment. This fact also contributes to the persistence of the strength of Washi through time. From measurements of infrared spectra of Washi samples, the amount of oxidation seems to be minimal.
Use of Network Analyzer and Coaxial Probe to Determine Complex Permittivity
Authors: Blackham David 
Published: March 2011

ABSTRACTA vector network analyzer combined with an open ended coaxial probe provides a way to make non-destructive measurements of complex permittivity. These measurements can be made on both solids and liquids.Many authors have done work on using an open ended coaxial line for making these measurements[1][2][3]. They have presented different techniques for modelling the coaxial probe. This paper does not focus on the area of modelling, but deals instead with the use of a vector network analyzer and coaxial probe in making measurements. To enhance measurement accuracy, the technique described adapts a calibration technique currently in use in vector network analysis.An HP 8720B vector network analyzer was used for the development and measurements presented in this paper.
Review of the French Activity in Microwave Control and Processing of Materials
Authors: Bolomey Jean-Charles , Metail Jean-Pierre 
Published: March 2011

ABSTRACTMaterials or, more generally, industrial products may be processed and/or controlled by means of microwave techniques. This paper presents a brief overview of the recent french activity related to such industrial applications of microwaves. For some of these applications, microwave techniques are already currently used while, for some others, studies are still conducted at a research and development level.
Anomalous Behavior of Heterogeneous Materials at Microwaves Frequencies: Introduction to Fractional Derivatives in Electromagnetism
Authors: Heliodore F. , Cottevieille D. , Mehaute A. Le 
Published: March 2011

ABSTRACTThe present note introduces new trends in electromagnetic spectroscopy in complex media.When an electromagnetic wave propagates in heterogeneous media, some questions arise about both physical meaning and validity range of the traditional analysis. The aim of our advanced research is related to the generalisation of Maxwell's equations able todescribe both homogeneous and heterogeneous media from an unique point of view.
Theory of Microwave Effects on Atomic Diffusion in Sintering: Basic Considerations of The Phenomenon of Thermal Runaway
Authors: Kenkre V. M. , Skala L. , Weiser M. W. , Katz J. D. 
Published: March 2011

ABSTRACTWe present the results of our recent studies of the possible origin of the reported increase in sintering efficiency brought about by the application of microwaves. We study the phenomenon of thermal runaway in ceramic materials undergoing microwave heating and present a theory on the basis of a simple temperature-time equation. The nonlinear evolution inherent in the equation arises naturally from physical considerations. The theory isapplied to experimental observations reported on several different materials including silica, alumina, strontium titanate, zinc oxide and iron oxide, and shown to be in good agreement with the data.
Microwave Sintering of Oxides
Authors: Aliouat M. , Mazo L. , Desgardin G. 
Published: March 2011

ABSTRACTMicrowave sintering of oxides has been studied, owing to its great flexibility for thermal treatments, which may influence in particular the microstructure and the electrical properties of the so sintered material. In order to point out the influence of the structure and electrical properties we studied the microwave sintering : i) of insulating complexe oxides with the perovskite structure, ii) of close packed structure such as spinelsand iii) of high Tc superconductors. The differents behaviours of those materials in a microwave field are compared and discussed.
Microwave Sintering Technology for the Production of Metal Oxide Varistors
Authors: McMahon G. , Pant A. , Sood R. , Ahmas A. , Holt R.T. 
Published: March 2011

ABSTRACTA microwave sintering technology has been developed for the production of metal oxide varistors. The electrical properties (leakage current and non-linearity coefficient) of the microwave sintered devices were found to be comparable to those obtained for conventionally sintered varistors of identical composition. Additionally, the reference voltages were greater (by a factor of two) and the biaxial moduli of rupture were higher for the microwave sintered specimens. These differences have been attributed to the smaller grain size associated with the microwave sintered specimens.
The Properties of Alumina Sintered in a 2.45 GHz Microwave Field.
Authors: Patterson Mark.C.L. , Kimber Robert M. , Apté Prasad S. 
Published: March 2011

ABSTRACTA method has been developed to reproducibly sinter high purity alumina (>99.8%) to densities in excess of 98% of theoretical. Sintering times of between 6 and 120 minutes have been investigated and a uniform grain structure is only obtained with sintering times greater than 30 minutes.Microwave sintering produces a product with a smaller, more uniform grain structure witha more narrow size distribution. The alumina is also tougher than the conventionally sintered material.When scaled—up to sinter batches of 400 grams, an energy consumption of 3.8 kWh/kg is required, which is estimated to be a 90% savings over conventional sinteringin an electric resistance furnace.
Microwave Processing of Silicon Nitride
Authors: Tiegs T. N. , Kiggans J. O. , Kimrey H. D. 
Published: March 2011

ABSTRACTMicrowave sintering of Si3N4—based materials showed improved densification as compared to samples heated conventionally under similar conditions. Accelerated nitridation of Si in the microwave furnace to produce Si3N4 was also observed. Dense Si3N4, annealed by microwave heating, exhibited enhanced grain growth; however preferential coupling of the microwave power to the grain—boundary phases in the present experiments resulted in their degradation.
Microwave Sintering of Nanocrystalline TiO2
Authors: Eastman J. A. , Sickafus K. E. , Katz J. D. , Boeke S. G. , Blake R. D. , Evans C. R. , Schwarz R. B. , Liao Y. X. 
Published: March 2011

ABSTRACTNanocrystalline TiO2 compacts having initial approximate mean grain sizes of 14 nm and approximate green densities of 70% of theoretical were sintered by short-time exposure in a 2.45 GHz microwave cavity to maximum temperatures of 800, 1000 or 1200 ºC. Sample densities were measured before and after exposure to microwaves using Archimede's method. Transmission electron microscopy and x-ray diffraction were utilized to monitor grain growth and phase changes. Rutherford backscattering was used to monitor any changes in oxygen stoichiometry. The results of this study indicate that enhanced densification behavior is obtained for microwavesintered samples relative to samples sintered using conventional pressureless-sintering techniques.
Thermal Effects During Microwave Plasma Sintering of Ceramics
Authors: Hsu Matthew , Sweeney Mwry P. , Johnson D. Lynn 
Published: March 2011

ABSTRACTA variety of ceramic materials have been heated in various microwave excited plasmas at reduced pressures. Temperatures were measured by optical fiber thermometry. Specimen heating was accomplished by direct contact with the plasma, as well as direct coupling withthe microwave energy, although the latter was screened heavily by the plasma. Higher specimen temperatures were achieved in polyatomic gases which have greater reactional enthalpy. In general, insulating materials achieved higher temperatures than semiconducting or covalently bonded materials.
Model-Informed Microwave Processing of Materials
Authors: Voss W.A. Geoffrey , Kua H.K. 
Published: March 2011

ABSTRACTThis paper reviews the expanding application of microwaves for processing solid materials, both natural and synthetic. The Canadian interest ranges from food processing to forest products, ceramic drying and curing to the preprocessing of rare minerals and ores, with the zeolite family of particular industrial interest.In all cases, across the world, the number of process variables is large and the known physical data are limited. Yet the engineer requires to know only a few specific properties which, in general, involve rate and limit functions. The problem posed here, which has to be considered as a part of the unification of the subject of electromagnetic heating, concerns the careful use of atomistic modelling to achieve a model-informed empiricism for process development. As an example, it is shown in this paper that the majority of solids have the same piecewise linear approximate temperature model for absorbing and reflecting power: more than twenty variables affecting the dielectric properties can then be reduced to five or six which need to be measured. Correctly interpreted, this approach (due, in its broad philosophic format, to M.F. Ashby, 1987) may help solve many electromagnetic engineering problems, including those associated with breakdown and thermal-runaway.
A Novel Microwave Device Designed to Preserve Cell Structure in Milliseconds
Authors: Login Gary R. , Kissell Susan , Dwyer Barbara K. , Dvorak Ann M. 
Published: March 2011

ABSTRACTWe describe an innovative microwave instrument, designed in collaboration with and owned by Raytheon Company. The instrument permits the manipulation of biological specimens in their fluid milieu during the actual period of rapid tissue fixation. The specimen chamber is designed for sample containers up to 1.7 cm in diameter and 4.5 cm in height. Reflected power is reproducibly low, limiting the need for pretuning the microwave output to the sample. Microwave exposure can be controlled in 1 msecond increments with a range of 10 mseconds to 10 seconds. Mammalian cells and tissues fixed by this microwave device were evaluated by light and electron microscopy. Preliminary findings show large regions of excellent preservation in tissues and in cell suspensions in -100 mseconds.
The Development of New Microwave Heating Applications at Ontario Hydro'S Research Division
Authors: Oda Steven J. , Balbaa Ibrahim S. , Barber Bruce T. 
Published: March 2011

ABSTRACTThis paper reviews the results from two relatively new microwave heating studies under development at Ontario Hydro's Research Division. The first study involves the development of a hybrid kiln to process advanced ceramics at high temperatures. Using a combination of resistive heating elements and microwave heating, this new device has been operated to show significant process advantages in terms of time and energy savings. A description of the hybrid kiln is presented together with the test results for calcining and sintering a variety of ceramic materials.The second investigation involves the use of microwave heating for the treatment of hazardous wastes. The selective heating ability of microwaves has been applied to reduce the environmental impact of wastes generated from industrial processes. An example is provided to illustrate the advantages and difficulties of applying this technology.
Enhanced Chemical Bonding at the Fiber-Matrix Interphase in Microwave Processed Composites
Authors: Drzal L. T. , Hook K. J. , Agrawal R. K. 
Published: March 2011

ABSTRACTThe effect of microwave processing on the chemical interactions occurring between the carbon fiber surface and the epoxy matrix constituents was investigated using X-ray Photoelectron Spectroscopy (XPS). Monofunctional model compounds of the matrix constituents were exposed to the carbon fibers at temperatures similar to those encountered during composite processing. The microwave treatment resulted in a substantial increase in the amount of chemical interaction between the fiber surface and the epoxy resin but little difference for the amine component of the matrix when compared to thermal processing. An epoxy resin/amine hardener adduct compound used to determine the hydroxyl group interaction with the carbon fiber surface indicated a low level of chemical interaction of the hydroxyl with the carbon fiber surface under the conditions used in this study.
The Consolidation and Processing of Graphite Fiber/Polymer Composites by Controlled Mode Microwaves
Authors: Treacy D.J. , Evans D.A. , Boyce J.S. , Mccoy J.F. , Treadway B.W. 
Published: March 2011

ABSTRACTComposite laminates have been cured under pressure in a tunable microwave cavity. A 7-in. diam cavity with a sliding short was tuned to produce single mode or controlled hybrid mode standing waves at 2.45 GHz. Graphite/epoxy laminates were processed with power inputs as low as 2 W/g.A low loss press was designed and built to operate inside the cavity. The press can apply 100 psi pressure on a 9-in. square laminate. An empirical approach has been used to develop processing conditions for high quality laminates. Graphite/epoxy composites were cured in 90 min or less. A simple on-off temperature control loop modulated power input to the cavity with a coaxial switch.Mechanical testing and differential scanning calorimetry have been used to evaluate the composites. The material properties have been related to processing conditions.
Microwave Heating for Manufacturing Carbon-Fiber Thermoplastics
Authors: Lind A.C. , Medgyesi-Mitschang L.N. , Kurz J.E. , Mckinney H.F. , Wear F.C. 
Published: March 2011

ABSTRACTTraditionally, polymeric composite parts are heated and consolidated in an autoclave. For large parts, such as transport aircraft fuselages or submarine hulls, size becomes a limiting factor. To overcome this limitation and to reduce labor costs we are developing an automated tape placement process. In this process we build composite parts one layer at a time with tape containing carbon fibers impregnated with a thermoplastic. As the tape comes into contact with the part, we apply heat to melt the thermoplastic and apply pressure to consolidate the tape to the part. To support this effort we have developed a proprietary microwave applicator that is suitable for rapidly heating carbon-fiber composites in an automated tape placement process. Small carbon-fiber/poly(aryl-ether-ether-ketone) parts made using the microwave applicator have interlaminar shear strengths of 100 MPa (14.5 ksi), which is almost equal to the 103 MPa (15.0 ksi) obtained using an autoclave.
Hydrolysis of Adenosine Triphosphate by Conventional or Microwave Heating
Authors: Jahngen Edwin G. E. , Lentz Ronald R. , Pesheck Peter S. , Sackett Patricia Holt 
Published: March 2011

ABSTRACTThe hydrolysis rate of adenosine-5'-triphosphate (ATP) has been reported to be 25 times greater during microwave heating than during conventional heating at comparable temperatures (100 to 105 °C). This remarkable rate increase was both attributed to and cited as evidence for a nonthermal microwave effect. Attempts to replicate those findings under carefully controlled microwave exposure conditions and with special attention being paid to accurate temperature measurements lead to the conclusion that the hydrolysis rate is related solely to temperature.
On-Line Transverse Control of Materials by Means of Microwave Imaging Techniques
Authors: Bolomey J.Ch. , Cottard G. , Cown B.J. 
Published: March 2011

ABSTRACTThis paper analyzes of the impact of a new generation of microwave sensors on the transverse control of conveyed products and materials. Such sensors, resulting from recent developments in microwave imaging technology, offer significant improvements in comparison to other more classical microwave sensors. The main features of the new sensors are presented and discussed.
Measurements of the Dielectric Properties of Irradiated Low-Loss by Microwave Reflectometry and Micro-Calorimetry
Authors: Buckley S.N. , Agnew P. 
Published: March 2011

ABSTRACTAn rf reflectometer has been used to measure dielectric losses in alumina ceramics during irradiation by 3 MeV protons. The equipment was able to detect tan ȯ changes of 5×10−5, but calibration by micro-calorimetry revealed large systematic losses, up to 2.5×10−3 Irradiation at 300 K resulted in a progressive increase in dielectric loss but no prompt increments.
Thermal Conduction Measurements of Materials using Microwave Energy
Authors: Giedd R. E. , Giedd G. R. 
Published: March 2011

ABSTRACTWe have developed a new technique to measure the thermal conductivity of materials using microwave energy. A thermal wave is induced in a material of unknown thermal conductivity using a pulse of microwave energy. This energy is incident on one side of the material. The corresponding temperature rise of the opposite side of the material is measured. The thermal diffusivity of the material can then be determined in the same way as ‘laser flash’[1]. Some of the advantages of the microwave system are the relatively low cost of the magnetron compared to the high energy laser, easily variable pulse length, and accurate measurement of the reflected energy.The microwave system consists of a 2.45 GHz magnetron that is pulse modulated to energies as high as 10 J. A typical pulse lasts for 1 ms with rise and fall times of 10µs. This is achieved by a high voltage source (5 – 8 kV at 1 – 2 A), switched by a high power, rf transmitting tube connected in the filament circuit of the magnetron.
Applications of Microwave Treatment of Hazardous Wastes: a) Non-Volatile Organics; b) Heavy Metals
Authors: Dauerman Leonard , Windgasse Gabriele , Gu Huiping , Ibrahim Nagui , Sedhom El-Hamy 
Published: March 2011

ABSTRACTThis laboratory is characterizing the mechanisms underlying the potential applications of microwave treatment to the remediation of hazardous waste streams under an Environmental Protection Agency Basic Research grant. Applications that have been investigated encompass the following processes(1-14): volatilization of organics from substrates; ‘chemical fixation’ of non-volatile organics in substrates; ‘chemical fixation’ of heavy metals in substrates; kinetics of decomposition of organics in the gas phase using fixed and ‘lossy’ beds. To-date the work has been carried out on a bench-scale level. Pilot plant studies are now beginning. This paper will focus on studies carried out on non-volatile organics and heavy metals, specifically, chromium.
A Unique Application of a Microwave Induced Plasma for Material Synthesis
Authors: Salsman Johanina B. , Holderfield S. P. 
Published: March 2011

ABSTRACTResearch conducted at the Bureau of Mines, Tuscaloosa Research Center has resulted in a process of forming tungsten carbide (WC) in a microwave induced plasma (MIP). This process allows for the formation of 99.96 pet WC with a 0.04 pet free carbon content and grain sizes on the order of 0.05 µm in approximately 10 minutes. Commercial methods of producing WC require that a mixture of metallic tungsten and elemental carbon be heated to temperatures of 1,500°C for up to 7 hours. Therefore, the new Bureau developed method is significantly less energy intensive, requiring only 13 pct of the energy used in conventional WC processing methods, and is less expensive although initial capital outlay may be high.The Bureau process involves using a 915 MHz, 30 kW variable power microwave generator to sustain a carbon monoxide plasma. The reaction chamber is constructed of a WR 975 rectangular waveguide that is short circuited at the end. The reaction takes place inside the waveguide at an electric field maximum. After the reaction chamber is readied, the microwave generator is turned on which ignites the plasma within seconds. In approximately 10 minutes, the reaction is complete resulting in a commercially acceptable product.
On the Development of Biomimetic Sensors: Immobilizaton of Lipid Bilayers in Layered Ceramics
Authors: Russell Michael W. , Mehrotra Vivek , Giannelis Emmanuel P. 
Published: March 2011

AbstractArtificial membranes possessing physicochemical properties similar to biological membranes have been synthesized by immobilization of synthetic amphiphiles in layered ceramics. The intercalated bilayer-forming amphiphiles exhibit a gallery height of about 39 Å. Retention of bilayer-forming characteristics is further confirmed by the presence of a crystal to liquid-crystal phase transition. A dramatic increase in the membrane capacitance at the tansition temperature is attributed to an increase in membrane fluidity.
Streptavidin-Phycoerythrin Conjugated Proteins Bound to Biotin on Langmuir-Blodgett Films of Biotinylated Lipid Monolayers
Authors: Samuelson Lynne A. , Kaplan D. L. , Marx K. A. , Miller P. , Galotti D. M. , Kumar J. , Tripathy S. K. 
Published: March 2011

AbstractStudies involving the specific and non-specific surface recognition of biotin on biotinylated LB lipid monolayers by streptavidin and avidin conjugated phycoerythrin are presented. Both streptavidin and avidin conjugates were injected under the monolayer and found to preferentially adsorb to the biotinylated monolayers at the air-water interface. Pressure-area isotherms displayed a biotin-streptavidin/avidin complex dependent increase in surface pressure at expanded areas indicating protein adsorption. The binding of protein was confirmed by transferring the monolayer films to solid supports and measuring the characteristic intense phycoerythrin fluorescence at 576 nm. The effect of protein charge, monolayer packing density and structure, and activation of the tetramer proteins towards specific and non-specific binding are discussed. These results suggest a novel and general methodology for the two-dimensional ordering of protein monolayers with potential bioelectronic, optical and protein structure research applications.