bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stability and Construction of Caverns for The Disposal Of Cemented Low-And Medium-Level Wastes
Authors: Raab W. , Frohn C. , Schmidt M.W. 
Published: March 2011

ABSTRACTThe geomechanical and mining-technological aspects of the construction of salt caverns as disposal chambers have been investigated during project phase 2, completed by mid 1981. With a view towards the stability analysis of such a cavern, FEM-estimates have been carried out and evaluated. From these it can be derived that- a rotational ellipsoid would be the most suitable shape- its dimensions should be 82 m (vertical axis) and 42 m (horizontal axis)- the distance (safety pillar) between the neighbouring caverns should be 170 m (vertical) and 180 m (horizontal).For practical engineering purposes the rotational ellipsoid can be modified into a cylinder with conic bottom and top. The numerical model simulated the short term as well as the long term characteristics of the surrounding salt rocks. The short term characteristics were assessed by an elastic approach, the long term characteristics by a rheological model. The input parameters have been determined by means of laboratory tests on ASSE rock salt.In a second step the characteristics of partially and completely filled caverns were simulated. It was shown clearly that deformation of the salt rock comes to a halt when counteracted by the filling.Based upon the results of the stability analysis, investigations were made to find out a suitable mining technique for the construction of the cavern. Solution mining and conventional development by means of drilling and blasting have been studied alternatively. Since both methods have their advantages and disadvantages a decision in favour of the one or the other cannot be made until the actual site has been defined.
Research Priorities for Nuclear Waste Isolation
Authors: Pigford T.H. 
Published: March 2011

Hr. Gordon's comments are specific to defense waste only. The research priorities center around:1.Improvements in the technology for immobilizing high-level waste. For waste vitrification, these improvements include lower corrosiveness, less crystal formation, lower volatility, reduction in glass cracking, increased life of glass-melter, nondestructive testing methods, and remote handling techniques.2.Better understanding of the performance of the waste package components in the repository environment. This requires additional research in the areas of repository characterization, the mechanisms of waste form corrosion, radionuclide migration in geologic media, predictive models for projecting waste system performance.. and synergistic effects of waste system components.3.Confirmation of waste disposal risk assessments and their establishment as the technical basis for regulatory criteria.4.Research priorities for transuranic (TRU) waste isolation are focused on the development of processing technologies for immobilization and of improved instrumentation for classification and nondestructive examination.
Dielectric Measurements of Particulate Organic Polymers
Authors: Bruce Ralph W. , Mccurdy M. W. 
Published: March 2011

ABSTRACTThe process of removing the entrained water within an organic polymer has been one focus of RF and microwave energy use in the plastics industry. This processing is critically dependent upon the absorption of the energy which in turn is dependent upon the frequency and the material's dielectric loss factor. Knowledge, therefore, of this value is of great importance and is the subject of this study. Measurements were made on several plastic samples as a function of both temperature and frequency.
Microwave Processing of Polymers
Authors: Lewis D. A. , Hedrick J. C. , Lyle G. D. , Ward T. C. , McGrath J. E. 
Published: March 2011

ABSTRACTNovel morphologies were produced in phase segmented, toughened epoxies via microwave processing. Novel and exciting chemistries have been demonstrated through the specificity of delivery of electromagnetic radiation in tuned cavities.
Microwave Processing of Polymers and Biomass Materials
Authors: George Clifford E. , Lightsey G. R. , Wehr A. G. 
Published: March 2011

ABSTRACTDielectric heating techniques have been applied to plastics drying applications, polymer blending, wood flour drying, and to an existing biomass conversion process. While both radio frequency and microwave equipment is expensive per unit of capacity, certain advantages may be gained in terms of the speed of drying, quality control, and the overall capitalized cost which may make dielectric heating feasible.
Enhanced Thermal Shock Properties of Y2O3-2 WT.% ZrO2 Heated Using 2.45 Ghz Radiation
Authors: Holcombe C. E. , Meek T. T. , Dykes N. L. 
Published: March 2011

ABSTRACTMicrowave sintering of Y2O3-2wt.% ZrO2 has produced microstructures which yield mechanical and thermal properties that differ from those observed in commercially sintered Y2O3-2wt.% ZrO2. This paper discusses mechanical and thermal property data obtained on samples of Y2O3-2wt.% ZrO2 heated using 2.45 GHz electromagnetic radiation.
Processing of Superconducting Ceramics Using Microwave Energy
Authors: Ahmad Iftikhar , Chandler G. T. , Clark D. E. 
Published: March 2011

ABSTRACTSuperconducting ceramics have been successfully prepared employing a novel internal heating mechanism which uses microwave energy. Calcining with microwaves requires further investigation to improve the superconducting properties. Sintering and annealing in microwave energy shows refined microstructure and improved oxygen content in the YBa2Cu3O7-x phase. This is attributed to the coupling of CuO with microwave energy. The onset of the superconductive transition occurs at 93°K for the conventionally calcined/microwave annealed samples. The conventionally processed samples have an onset transition at 90°K and exhibit weaker diamagnetism when compared with the microwave annealed sample.
The Effects of Power Level on the Microwave Heating of Selected Chemicals and Minerals
Authors: McGill S. L. , Walkiewicz J. W. , Smyres G. A. 
Published: March 2011

ABSTRACTThe effect of power level on the microwave heating characteristics of a variety of reagent-grade chemicals and minerals has been determined in a Bureau of Mines study. Heating rates of the powdered samples are presented for incident power ranging from 500 to 2,000 W at 2.45 GHz. The apparatus consisted of a WR 975 waveguide-applicator mounted to WR 284 waveguide sections and connected to a 3-kW power source. Tests were conducted in an alumina crucible enclosed in a fused-quartz beaker that was fitted with a Teflon lid to allow for a controlled inert atmosphere and thermocouple insertion. In general, heating rates increased as input power increased. Exceptions to this were some very high-lossy (microwave receptive) and very low-lossy materials that showed negligible changes with increased power. Microwave data collected should provide insight as to possible chemical and mineral processing applications as well as to assist in predictions of processing parameters.
Microwave Joining of Ceramics
Authors: Palaith David , Silberglitt Richard , Wu Carl C. M. , Kleiner Ricrjard , Libeld E. Laurence 
Published: March 2011

ABSTRACTThis paper presents a process developed at Quest Research Corporation for using microwave energy to join ceramics. It begins with a brief overview of the concept and a recent history of microwave ceramic processing. A mathematical treatment of the microwave heating process then is presented followed by a description of the joining technique, and a summary of the experimental results and joint characterizations. For one set of ceramic samples used, electron microscopy and fracture toughness and hardness measurements were made at the Naval Research Laboratory. Another set of sample material was provided by Coors and photomicrographic evaluations of joints produced by Quest using these samples were performed by Coors.
Microwave Heating of Ceramics and its Application to Joining
Authors: Fukushima H. , Yamanaka T. , Matsui M. 
Published: March 2011

ABSTRACTA new butt joining method for ceramics by microwave heating was developed. Ceramics were heated in a rectangular cavity. A klystron of maximum 3 kW at 6 GHz was used as the power amplifier. The heating system can control the iris, plunger and microwave power to keep a power efficiency up to 90% and a accuracy within ±10°C at 1800°C. Microwave ceramic-ceramic joining was tried by using this system. A bending strength of the joined alumina rod (92% purity) was 420 MPa without adhesive. This value was equal to the original strength. Silicon nitride ceramics were joined with adhesive, which was a sintered ceramic sheet having lower purity and larger dielectric loss factor than the base ceramics. The microwave energy was concentrated on the sheet, so that only the joining area was heated. The strengths of joined specimens were in excess of 70% of original strengths. The joined boundary line was not detected in microscopic observation, and there was little difference in microstructure between before and after joining. These results suggest that sintering aids in grain boundary phases were preferentially heated and melted or diffused, resulting in sound joining of ceramics.
Improved Grindability of Iron Ores using Microwave Energy
Authors: Walkiewicz J. W. , McGill S. L. , Moyer L. A. 
Published: March 2011

ABSTRACTThe Bureau of Mines, U.S. Department of the Interior, has conducted studies to utilize rapid microwave heating to stress fracture ore samples. Iron ores containing hematite, magnetite, and goethite were subjected to microwave energy in batch operations at 3 kW and heated to average temperatures between 840° and 940° C. Scanning electron microscope (SEM) photomicrographs verified fracturing along grain boundaries and throughout the gangue matrix. Standard Bond grindability tests showed that microwave heating reduced the work index of iron ores by 9.9 to 23.7 pct. Preliminary studies using a continuous feed belt in a microwave applicator indicated that samples heat more uniformly and with better temperature control than in batch operations.
Rapid Electromagnetic Induction Bonding of Composites, Plastics, & Metals
Authors: Buckley John D. , Fox Robert L. 
Published: March 2011

ABSTRACTA rapid electromagnetic induction bonding system has been developed that joins composites, plastics, metals, and combinations of these materials. The equipment is self-contained, low power (100–400 watts) and portable. Gangs of bonders have been used as a seem welder to rapidly join plastic reinforced composite and sheet metal. Structures can be bonded in a factory or in the field. Bonding times for laboratory specimens have been cut by a factor of 10 to 100 times compared to standard press or autoclave bonding. This type of equipment allows for applying heat directly to the bond lines and/or the adherends without heating the entire structure, supports, and fixtures of a bonding assembly.The bonder's portability and low power requirements allow for its use on site in any type of climate with power supplied by a variety of portable sources.
A Research Program for Dielectric Heating and Drying of Industrial Materials
Authors: Pearce John A. , Yang S. I. , Schmidt P. S. 
Published: March 2011

ABSTRACTA comprehensive program of research into dielectricallyassisted heating and drying of industrial products includes studies of the heat and mass transport processes and the spatial distribution of microwave (MW) and radio frequency (RF) power deposition in the objects of interest. Such studies enable the design of product specific drying machinery.
Thermodiffusion - A New Approach To Plasma Self-Confinement
Authors: Forchel A. , Laurich B. , Mahler G. 
Published: March 2011

ABSTRACTFrom a model for the thermodiffusion of high density plasmas an electronic mechanism for plasma self-confinement is derived. Due to the increase of the confinement densities with the density of states masses this effect should be most important in laser annealing experiments in Si but much weaker in GaAs. A fast diffusion of the surface generated plasma is found to enhance the impact ionization rate.
Femtosecond Time Resolved Reflectivity of Optically Excited Silicon
Authors: Yen R. , Shank C. V. , Hirlimann C. 
Published: March 2011

ABSTRACTWe report measurements of the time resolved reflectivity of Silicon following excitation with an intense 90 femtosecond optical pulse. These measurements clearly time resolve the process of energy transfer from the optically excited electron-hole plasma to the crystal lattice and subsequent melting within the first few picoseconds.
Charged Dangling Bonds and Crystallization in Group IV Semiconductors
Authors: Germain P.J. , Paesler M.A. , Sayers D.E. , Zellama K. 
Published: March 2011

ABSTRACTCrystallization of amorphous Ge (or Si) has been studied as a function of temperature and the flux of ionizing radiation (or doping). The crystallization growth rate Vg takes on the form Vg = vo exp(−E/kT) where vo is an increasing function of flux (or doping). We propose the following to explain these data: A concentration of mobile dangling bonds (DBs) exists in the bulk and near the amorphous-crystalline (a-c) interface. Ionization and doping induce transitions from the uncharged state Do to the charged states D+ and D−. The process controlling crystallization resulting in the above activation energy is discussed. Only certain sites on the a-side of the a-c interface are available for crystallization, and these sites are those which have captured DBs. The charged D+; and D− states have a larger capture cross section than the uncharged Do state. Increased concentrations of charged DBs results in an enhancement of the prefactor in the above equation.
Laser-Induced Solid Phase Crystallization in Amorphous Silicon Films
Authors: Olson G.L. , Kokorowski S.A. , Roth J.A. , Hess L.D. 
Published: March 2011

ABSTRACTWe review recent work on the kinetics of laser-induced solid phase epitaxial crystallization of silicon as determined from time-resolved reflectivity measurements. Specific topics which are addressed include: the intrinsic kinetics of solid phase epitaxy (SPE) in ion-implanted and UHV-deposited films; SPE rate enhancement by implanted dopant atoms and the effects of electrical compensation on the SPE rate; and the temperature dependence of SPE and competing processes in samples containing impurity atoms at concentrations exceeding the solid solubility limit. The high temperature kinetics results are compared with predictions from transition state theory and are discussed with respect to a proposed depression in the amorphous Si melting temperature.
Explosive Crystallization in a-Ge and a-Si : A Review
Authors: Bensahel D. , Auvert G. 
Published: March 2011

ABSTRACT:Self-sustained or explosive crystallization results on a-Si and a-Ge are reviewed and compared. cw laser experiments on a-Si allow to follow all the phenomena encountered, and to experimentally measure the crystallization front velocity. The published theories agree well with the experimental results on a-Si. Moreover, a-Ge presents the same behaviour as a-Si, but for a-Si, the high nucleation rate can induce a specific explosive growth.
Surface Electromagnetic Waves in Laser Material Interactions
Authors: Ehrlich D. J. , Brueck S. R. J. , Tsao J. Y. 
Published: March 2011

ABSTRACTTransient ripple formation in pulsed laser annealing of semiconductor materials is shown to arise from amplified surface polariton scattering. The permanent ripple patterns are frozen in after transverse thermal and material diffusion during the laser-annealing process. The model is in good agreement with time-resolved measurements of the ripple formation in 1.06−µm laser annealing of Ge. Dispersion of the ripple wavevector in the UV spectral region is discussed.
Laser Induced Periodic Surface Structure
Authors: Van Driel H.M. , Young Jeff F. , Sipe J.E. 
Published: March 2011

ABSTRACTLaser induced periodic surface structure can be understood as a universal phenomenon which occurs when high intensity pulses are absorbed near the surface of solids or liquids. The phenomenon occurs on metals, semiconductors and insulators because of the interference between the incident pulse and an induced “radiation remnant”. This scattered field may be enhanced by the existence of true surface modes such as surface plasmons or phonon-polaritons but this is not essential. The universality characteristics include beam polarization, since we show that circularly polarized light can induce surface ripples, with the damage structure showing a dependence on the sense of rotation. We also present time resolved results of the formation of the ripples to illustrate the essential dynamical processes that occur.
Impurity Diffusion in Silicon Annealed by Semi-Continuous Laser
Authors: Bouree Jean-Eric , Leray Claude , Rodot Michel 
Published: March 2011

ABSTRACTThe diffusion of an impurity into a solid which is irradiated by laser pulses of some milliseconds duration has been analysed in terms of effective diffusion time and temperature. In the case of Fe in Si, the diffusion coefficient is found to be similar to that measured by COLLINS and CARLSON, and independent of boron doping. In the case of Al in Si, a value of 2.10–10 cm2/ at 1400°C has been found both for single crystals and for fine-grained polycrystals.
Search for Vacancies in Laser Annealed Silicon
Authors: Stein H. J. , Peercy P. S. 
Published: March 2011

ABSTRACTIn an effort to enhance vacancy trapping and detection in laser-annealed Si, float zone Si was implanted with oxygen to achieve concentrations between one and two orders of magnitude greater than the equilibrium saturation limit. Oxygen, which is known to be an effective trap for vacancies, was found to incorporate efficiently into Si regrown with Q-switched laser annealing Interstitial oxygen, oxygen-vacancy defects and divacancies were observed after implantation. The laser-regrown layers, however, were free of detectable vacancy-associated defects.
Microprobe Raman Analysis of Picosecond Laser Annealing of Implanted Silicon
Authors: Sapriel J. , Nissim Y.I. , Oudar J.L. 
Published: March 2011

ABSTRACTPicosecond laser annealing has been performed on implantationamorphised silicon. A multiannular (up to five rings) recrystallization pattern has been generated by a single~30 psec pulse at 1.06 μM and 0.53 μm wavelength and energy density just below the damage threshold. The different patterns have been investigated by scanning the surface with a Raman microprobe with a 1pm spacial resolution. Information are thus given on the different phases (amorphous or crystalline) and on lateral as well as in depth dimensions of the different rings.
Analysis of Temperature and Stress Profiles Induced by a cw Line Scanned Electron Beam in <100> Oriented Silicon
Authors: Bentini G. G. , Correra L. 
Published: March 2011

ABSTRACTEvaluation of thermal profiles along the scan direction of a line shaped e-beam as well as the topographic distribution of the thermally induced stresses have been performed by solving the heat diffusion equation for several incident power values. The resulting stresses have been computed in the “nearly isotropic” approximation but taking into account that the slip planes, in <100> oriented silicon crystals, are{lll} and the slip directions in the plane are <110>.The threshold of damage introduction has been evaluated by comparing the computed stresses with the yield stress of the material at any annealing temperature. Experimental observations based on X-Ray topography have been performed in order to study the damage introduction on <100> silicon samples annealed in the same conditions used for stress computation. A very good agreement between computed and experimental results was found.
Ising Model Simulations Of Impurity Trapping in Silicon
Authors: Gilmer George H. 
Published: March 2011

ABSTRACTLaser annealing experiments on silicon have shown that rapid solidification can trap large amounts of certain impurities in the crystal lattice. Concentrations that exceed the equilibrium solubility limits by several orders of magnitude have been obtained. In this paper we discuss the impurity trapping process using Monte Carlo simulation data from the kinetic Ising model. The dependence of the impurity concentration in the crystalon the solidification rate is calculated. The simulation data are compared with recent laser annealing results for bismuth and indium. Excellent agreement between the model and the bismuth experiments is obtained. The larger trapping rate on the (111) relative to the (100) orientation is found to be caused by the slower crystallization kinetics on the (111) face. Similar results are obtained for indium, although the difference in trapping on the (111) and (100) faces is somewhat smaller in the model than in the experiment.
Amorphous Si, Crystallization And Melting
Authors: Poate J. M. 
Published: March 2011

AbstractRecent experiments dealing with the thermodynamics of crystallization and melting of amorphous Si are reviewed. differential scanning calorimetry measurements give the heat of crystallization of implanted, amorphous Si to be 11.3±t.8 kJ/mole. Gibbs free energy calculation based on these measurements indicate that amorphous Si melts at a temperature of 1460°K compared to the crystalline value of 1685°K. Evidence for this reduced melting temperature also comes from rapid heating measurements using a) structural information after solidification and b) dynamic conductance measurements during the melt. Solid phase epitaxial regrowth experiments which apparently do not show such a depression in amorphous melting temperature will be discussed.
Segregation and Crystallization Phenomena in Germanium
Authors: Clark G. J. , Cullis A. G. , Jacobson D. C. , Poate J. M. , Thompson Michael O. 
Published: March 2011

ABSTRACTWhile many studies have been made of liquid phase epitaxy impurity trapping and segregation in Si little is known about the equivalent processes in Ge. In this paper we have laser annealed Ge <100> and <111> crystals implanted, at liquid nitrogen temperature, with 200 keV 210Bi ions to doses of 2 × 1015 and 1016 ions cm−2. The samples were annealed with Q-switched ruby lasers and an XeCl excimer laser. We have observed 1) velocity and orientation dependence of the Bi segregation coefficient 2) interface instability and cell formation resulting from constitutional supercooling and 3) amorphization and defect production at high velocities. The phenomena are shown to be analogous to those seen in Si.
Effect of Pulse Duration on the Annealing of Ion Implanted Silicon With A XeCl Excimer Laser And Solar Cells
Authors: Young R. T. , Narayan J. , Christie W. H. , van der LEEDEN G. A. , Rothe D. E. , Sandstrom R. L. 
Published: March 2011

ABSTRACTThe advantages of pulsed excimer lasers for semiconductor processing are reviewed. Studies of XeCl excimer laser annealing with pulses of 25 and 70 nsec duration and energy densities in the range from 0.5–3.0 J/cm2 are discussed. The annealing characteristics are described in terms of the results of melt depth, dopant profile spreading, and electrical properties (sheet resistivity, diode characteristics) measurements. Solar cells with efficiencies as high as 16.7% AMI have been fabricated using glow discharge implantation and XeCl laser annealing.