bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Mount Technology (SMT) Substrate Material Requirements - A Brief Review
Authors: Ibrahim A. Mahammad
Published: March 2011

The state of the art for the printed circuit (pc) industry is the Surface Mount Technology (SMT) using leadless ceramic chip carriers (LCCCs). The SMT technique is used to design, fabricate, and assemble affordable high-speed, high-density electronic modules with reduced size and weight. However, to take full advantage of the SMT, new high-performance printed circuit board (PCB) substrate materials must be developed, especially if the goal is to satisfy the high reliability required in military applications. The most critical requirement is matching the in-plane coefficient of thermal expansion (CTE) with the SMT-PCB's and the chip carriers (LCCCs) to reduce the solderjoint stresses during thermal cycling. Solder-joint reliability can be improved significantly by tailoring the in-plane CTE to approximately 6–7 ppm/°C (of the alumina chip carrier) using Kevlar and/or quartz fabric-reinforced polymer composites, instead of conventional glass composites. Less attention has been focussed on other important requirements, e.g., out-of-plane (Z-axis) expansion, glass transition temperature (Tg), dielectric constant, and resin microcracking, which also play important roles in the overall performance of the substrate materials. For example, high Z-expansion puts additional strain on the plated through holes (PTH), thereby affecting PTR reliability. A low Tgsignificantly increases the amount of thermal stress imposed during thermal cycling on solder joints and PTH, and leads to failures. This paper contains a brief review of the requirements of a SMT-PCB substrate material, including such critical parameters as: in-plane CTE, out-of-plane CTE, Tg, dielectric constant, fiber-to-resin ratio, and resin microcracking, and their effects on solder joint reliability, PTH reliability, dimensional stability, and electrical performance.
Chromium-Polyimide Interface Chemistry
Authors: Goldberg M. J. , Clabes J. G. , Viehbeck A. , Kovac C. A.
Published: March 2011

We have studied the reactions occurring for the deposition of chromium onto pyromellitic dianhydride -4,4′-oxydianiline (PMDA-ODA) polyimide for a wide range of metal coverages, using X-ray photoelectron spectroscopy as well as solution studies involving model compounds. A multi-step, coverage-dependent, mechanism is proposed which includes an initial electron transfer from Cr to PMDA-ODA. followed by formation of Cr-O and and Cr-N polymer-bound intermediates, At higher metal coverage, Cr-oxides and Cr-nitrides are formed which may activate the polymer for subsequent formation of Cr-carbide. No evidence was obtained in support of a model involving initial formation of a π-arene complex between chromium atoms and PMDA-ODA. In the course of this work we have shown that similarities exist between the chemistry of metal atoms in condensed phases and the reactions occurring between metal atoms and surfaces.
Superconducting Interconnections in Future High Performance Systems
Authors: Frye R. C.
Published: March 2011

New, high temperature superconducting materials could eventually be used for interconnections in electronic systems. Such interconnections would undoubtedly cost more to implement than conventional ones, so the most likely applications would be for complex, high-speed systems that could benefit from the performance advantages of a resistance-free interconnecting medium. The problem with conventional conductors in these systems is that the resistance of wires increases quadratically as dimensions are scaled down. The most important advantage offered by superconductors is that they are not linked to this scaling rule. Their principal limitation is the maximum current density that they will support and this determines the range of applications for which they are superior to conventional conductors. An analysis will be presented which examines the relative advantages of superconductors for different critical current densities, wire dimensions and system sizes.

If their critical current densities are adequate, and if they can statisfy a number of processing criteria, then superconductors could find useful applications in a number of high performance electronic systems. The most likely applications will be those demanding very high interconnection densities. Several of these systems will be discussed.
Spin-On Glass Films in Multilevel Ic Interconnection
Authors: Gupta Satish K.
Published: March 2011

Among the variety of techniques available today for interlevel dielectric planarization, techniques based on spin-on glass (SOG) films are relatively attractive because of process simplicity and minimal equipment requirements. This paper reviews the materials and processes of SOG technology as it is applied in dielectric planarization. The SOG planarization schemes employ SOG films either as a permanent part of the interlevel insulation layer or as a sacrificial layer in the ‘etch-back” techniques. The properties of the various types of comnircially available SOG materials are discussed in relation to their functional and processing characteristics.
Materials and Processes for High Functionality Hybrid Circuit Packages
Authors: Jaffe Donald
Published: March 2011

Materials and processes used for high functionality hybrid circuit packages based on ceramic substrates are described. Emphasis is on hybrid circuits used for telecommunications and related applications. Examples include packages utilizing thin film technology, thick film technology and combinations of the two technologies. Various thick and thin multilayer approaches to achieve high interconnection density are discussed. These employ a variety of metal conducting systems in conjunction with glasses and/or polymeric materials as dielectric insulating layers.
Packaging of Components for Optical Fiber Technoidgy
Authors: Sriram S. , Homian R. L.
Published: March 2011

A number of promising tedcniques used to intercmnect two or more optical fibers and optical fibers with guided wave optical devices are reviewed. Such waveguide-to-waveguide interconnections impose severe optical and mechanical design constraints. components used in single mode infrared optical systems use fibers of five to ten microns in core diameter. This creates the need for subnicron alignment toleranc between the waveguides. Such severe toleranc requirements are satisfied, in the case of single mode fiber connectors, through the use of precision ceramic ferrules. Achieving the same performance, when interconnecting fibers and waveguide devices, is somewhat less straightforward. Several approaches are currently under study. One such approach uses precisely etched silicon V-grooves. Another approach uses self-aligned grooves or slots that are formed in the substrate material through ion-milling or laser-assisted etching. Components used in multimode fiber systems use fiber with fifty to one thousand micron core diameters, and are therefore more forgiving to misalignment. Despite this, careful design is required to achieve satisfactory performance. The misalignment penalties associated with a number of interconnect situations are illustrated and discussed in terms of alignment tolerances and fabrication difficulties.
Measurement of Die Stress from Packaging and Effects of Thermal Cycling
Authors: Robinson Murray J. , Tsay Cliff , Buynoski Matthew , Pendse Rajendra
Published: March 2011

During the processing and packaging of silicon integrated circuits there are many sources of die stress. Probably the least understood and controlled is the stress introduced during the die attach and molding processes. The largest packaging stresses are due to the mismatch of the thermal expansion coefficients between the leadframe and the die,and the die and the molding material. We report results obtained by monitoring the resistance changes of implanted, p-type resistors, undergoing various heat treatments with a matrix of mold and leadframe materials.
Ceramic Optical Package: Material Requirements and Guidelines for Material Selection
Authors: Yan M. F. , Rhodes W. W.
Published: March 2011

Recently Lightwave Device Packaging Department at AT&T Bell Laboratories has demonstrated that ceramic materials can provide cost effective and high quality packages to house optical and electronic components for lightwave communication applications. In this paper we examine the material requirements for optical packages. We also study the material properties of metals and ceramics with a potential application in optical packages. In particular, we review hermeticity, thermal conductivity, thermal expansion coefficient, dielectric constant, electrical resistivity, sintering temperature and mechanical strength of these materials. Our study will provide a data base and useful guidelines for designers to make uniformed decisions on material selection for optical package. We also review the mixing rules to predict the resultant property of a composite from the known attributes of its constituents and the use of new composite materials will provide a new degree of flexibility in the optical package design.
High Frequency Dielectric Response of Calcium Aluminate Cements: Potential Packaging Substrate Materials
Authors: Sliva Paul , Leffler M. , Bliss M. , Cross L. E. , Scheetz B. E.
Published: March 2011

Dielectric permittivity and loss tangent were measured on: 1) pressed disks of four different calcium aluminate cements shear mixed with water and poly(vinyl alcohol) and cured at room temperature and 2) laminates of SECAR 71 cement sintered at 1450°C. Post resonance and perturbation methods were used for microwave frequency measurements. Far infrared dielectric response of the cements was determined by FTIR in the diffuse reflectance mode. The real and imaginary parts of the relative dielectric permittivity were obtained via a conventional Kramers-Kronig analysis.
Multilayer Analysis by Focused MeV Ion Beam
Authors: Takai M. , Kinomura A. , Izumi M. , Matsunaga K. , Inoue K. , Gamo K. , Satou M. , Namba S.
Published: March 2011

A high-energy (MeV) helium ion beam has been focused down to 1 μm by a combination of piezo-driven objective slits and a magnetic quadrupole doublet. Rutherford backscattering (RBS) mapping techniques using focused MeV ion beams were, for the first time, applied to multilayered structures of metals, isolated with insulators, representing a test structure for multilayered wiring or interconnections of integrated circuits to nondestructively analyze the imperfection of the structures.
Reaction Mechanisms in Organic Binder Removal During Ceramic Processing: PMMA/Cordierite as a Prototype System
Authors: Farnethe William E. , Staley Ralph H. , Budzichowski Theodore
Published: March 2011

As the performance requirements of ceramic components are refined, the demands placed on the materials used in their processing also become more stringent. For example, in advanced ceramic packaging applications, it is increasingly important that the organic polymers used as binders be capable of degradation and removal at low temperatures and in non-oxidizing atmospheres. This paper examines the chemistry that can occur during two fundamental stages of the binder removal process, (1) the breakdown of the C–C backbone of the polymer during pyrolysis, and (2) the interaction of the small molecules that are produced during pyrolysis with ceramic surfaces. The work has focused on acrylate and methacrylate systems, both because this is an important family of polymers for applications in tape casting, and because there is a relatively extensive literature on their pyrolysis chemistry.
Effects of Waste Composition and Loading on the Chemical Durability of a Borosilicate Glass
Authors: Clark D.E. , Maurer C.A. , Jurgensen A.R. , Urwongse L.
Published: March 2011

The effects of waste composition and percent loading in a borosilicate glass designed for US defense high level wastes (HLW) have been evaluated. Three types of simulated wastes were investigated; high alumina, high iron and a composite representative of an average waste composition from Savannah River Plant (SRP) waste tanks. Corrosion resistance of the borosilicate glass is significantly enhanced by the presence of any of the three types of wastes. Additionally, corrosion resistance is improved as the % waste loading is increased in the glass. The best corrosion performance was obtained with the high alumina waste in deionized water.
Leaching of Actinides from Simulated Nuclear Waste Glass
Authors: Pickering S. , Walker C.T. , Offermann P.
Published: March 2011

The aim of the work was to measure the resistance of simulated nuclear waste glasses to leaching by water and salt solution under the conditions of elevated temperature and pressure. Of particular interest was the behaviour of Am and Np.
Influence of a Backfilling Material on Borosilicate Glass Leaching
Authors: Lanza F. , Ronsecco C.
Published: March 2011

When a canister containing a borosilicate glass incorporating highly radioactive waste is put into an underground repository, care must be taken in favouring the dispersion of the generated decay heat by conduction in the surrounding rock. For this purpose the space existing between the glass container and the repository walls is filled with a material having an acceptable thermal conductivity. If the backfilling material is highly compacted, it can form a zone of very low permeability reducing in this way the flow of water around the canister.
Results from a One-Year Leach Test: Long-Term Use of Mcc-L
Authors: Strachan D. M.
Published: March 2011

The Nuclear Waste Materials Characterization Center at Pacific Northwest Laboratory is developing standard tests to obtain data on nuclear waste forms, barriers, and backfills. These tests include performance measurements of thermal, radiation, mechanical, and chemical properties. Five tests have been developed to determine the chemical durability of waste forms under either static (MCC-IP and MCC-2P) or flowing (MCC-4S and MCC-5S) leaching environments. Maximum credible release by waste forms is determined using powders and stirred solutions (MCC-3S).
Quantitative Determination of Crystalline Phases in Nuclear Waste Glasses
Authors: Feld R. H. , Stammler M.
Published: March 2011

In order to assess the longterm chemical and physical stability of high level waste glasses it is important to know the amounts of crystalline phases present.

In principal all information about the crystalline state can be derived from its X-ray powder diffraction pattern,provided the spectral resolution is sufficiently high. Powderdiffraction techniques are the only means available to determine the concentration of crystalline phases in the presence of equivalent amorphous components. In addition it permits the determination of specific crystalline phases in a multicomponent system.
Effect of Fe2O3/ZnO on Two Glass Compositions for Solidification of Swedish Nuclear Wastes
Authors: Nogues J. L. , Hench L. L.
Published: March 2011

A recent study concluded that addition of Fe203 to a soda borosilicate nuclear waste glass may significantly reduce damage by water attack due to formation of a Fe-rich film on the glass surface. However, differences in SiO2, B203, CaO, and concentration of fission products in previous glass compositions make it impossible to ascribe the improved leach resistance solely to Fe203 content. In the present work, leaching behavior of two glasses are compared which differ only by the substitution of Fe203 for some of the ZnO in the glass. Both glass compositions, Table 1, are compatible with the French AVM process and contain 9% (by weight) of simulated waste products characteristic of the Swedish nulcear waste program.
Structural Effects of Radiation Damage in Silica Based Glasses
Authors: Manara A. , Gibson P.N , Antonini M.
Published: March 2011

The results of recent measurements of optical absorption, etching rate and transmission electron microscopy in pure silica and borosilicate glasses are reported and discussed. At dose saturation conditions, the dependence of the optical density associated with the production of single atomic defects from the mass of the impinging particle shows a marked saturation at masses ≥ 20 amu. The corresponding etching rates increase by about 4 times with respect to unirradiated samples. In borosilicate glasses, the temperature dependence of the threshold dose rate of electrons to initiate the nucleation of bubbles shows a marked increase from about 300° to 600° K.
Dose-Dependence of Pb-Ion Implantation Damage in Zirconolite, Hollandite, and Zircon
Authors: Headley T. J. , Arnold G. W. , Northrup C. J. M.
Published: March 2011

The long-term stability of nuclear waste forms is an important consideration in their selection for safe disposal of radioactive waste. Stability against long-term radiation damage is particularly difficult to assess by short-term laboratory experiments. Much of the displacement damage in high-level waste forms will be generated by heavy recoil nuclei emitted during the α-decay process of long-lived actinide elements. Hence, an accelerated aging test which reliably simulates the α-recoil damage accumulated during thousands of years of storage is desirable. One recent approach to this simulation is to implant the waste form with heavy Pb-ions.I- 6 If the validity of this approach is to be fully assessed, two important questions which have not yet been investigated must be answered.(1) Is the structural damage, including cumulative effects, similar for irradiation by Pb-ions and a-recoil nuclei in a given material? (2) Is the dose-dependence of the accumulated damage similar? The purpose of this investigation was to assess the extent of these similarities in selected materials. We utilized transmission electron microscopy (TEM) to characterize the radiation damage and measure its dose-dependence.
Leachability of Zircon as a Function of Alpha Dose
Authors: Ewing Rodney C. , Haaker Richard F. , Lutze Werner
Published: March 2011

The variation in the leachability of naturally occurring zircons (ZrSiO4) as a function of total alpha dose has been measured at 87°C. For calculated doses in the range of 1016to 1018alphas/gm there is an increase of one order of magnitude in the weight percent of zircon that is dissolved and an increase in the leach rate of the zircon 2.9 × 10−8to 2.3 × 10×7gm/cm2day. Totally metamict specimens (dose ≥ 1019alphas/gm) have leach rates as high as 1.8 × 10−6gm/cm2day.
Dissolution of Evaporites and its Possible Impact Cn the Integrity of the Waste Isolaticn Pilot Plant (Wipp) New Mexico, USA
Authors: Zand Siavcsh M.
Published: March 2011

The purposes of this report are: (1) to discuss the manifestation of dissolution processes (such as land subsidence and method of formation of breccia pipes and brine reservoirs) in the bedded salt of southeastern New Mexico in the vicinity of the WIPP site, (2) to postulate conditions under which breaches of the repository might occur, (3) to discuss radiological consequences of such breaches, and (4) to identify areas that need further investigation.
Long-Term Radioactivity Release From Solidified High-Level Waste -Part I: An Approach To Evaluating Experimental Data
Authors: Altenhein Friedrich K. , Lutze Werner , Ewing Rodney C.
Published: March 2011

Safety and risk analyses for the isolation of radioactive waste in a repository must begin with a source term to quantify the amount of radioactivity released from the waste form under a specific set of conditions. The interaction of the waste form with aqueous solutions is the most important mechanism to consider, as any material released may be dissolved and reach the biosphere. In this regard the behaviour of heat generating high-level waste is of particular importance, because reaction rates are higher at elevated temperatures. A long-term leach rate was derived from previous and continuing experimental work. The purpose of this paper is not to describe the “real case” release but rather to provide guidelines for the design of leaching experiments and determine the required precision for the data. This can be derived from the relative sensitivity of extrapolated leach rates for various parameters measured in laboratory experiments.
Investigations of the Solution Behaviour of NaCl in the Quinary System NaCl-KCl-MgCl2-MgSO4-H2O at Different Temperatures
Authors: ConRadt R. , Eengelke H. , Kaiser A.
Published: March 2011

The German concept of high level waste final storage by the aid of waste glasses is based on rock salt formations as deposits. Investigations consider the accidental case of water entrance into the deposit where the waste forms then are exposed to highly concentrated salt brines at elevated temperatures and pressures.
Investigation of Diffusion of UO2Cl2 in Saturated NaCl Solutions at Various Temperatures
Authors: Murso Harry , Plewinsky Bodo , Leopold Dieter , Marx Gonter
Published: March 2011

Even in the early 1960's it had already been decided to place high-level radioactive waste in the salt formations of the Federal Republic of Germany. However a major concern is the formation of highly corrosive brines in the event of water filling the repositories. In order to estimate the risks of waste storage in salt repositories it is necessary to investigate the physicochemical properties of the waste materials and of those radionuclides extracted into brine. The extraction of radionuclides from borosilicate glasses or spent fuel elements has been discussed, taking into consideration the two transport mechanisms: diffusion and convection.
Diffusion in Crystalline Rocks
Authors: Skagius K. , Neretnieks I.
Published: March 2011

Laboratory experiments to determine the sorption and the rate of diffusion of cesium and strontium in pieces of granite have been performed. The effective diffusivity, Dp ep was found to be I-2, 10-12 m2/2 for both cesium and strontium.
Model for Near Field Migration
Authors: Andersson G. , Rasmuson A. , Neretnieks I.
Published: March 2011

A model is proposed which describes the transport to and from a waste canister in a repository. The model includes flow and diffusion in the fractures in the bedrock as well as diffusion in the backfill. Calculations have been made on the inward transport of corrosive agents to a buried canister from the surrounding bedrock. The oxidants are transported from the flowing groundwater through the backfill to the surface of the canister, were they are assumed to react instantaneously with the canister material. The rock is modeled as a discrete fracture
system. The fractures are assumed to be evenly spaced and the groundwater movement is described by potential flow. The model is three dimensional.
Model for Far Field Migration
Authors: Rasmuson Anders , Neretnieks Ivars
Published: March 2011

A transport model of radionuclide migration in fissured rock is presented. It includes advection and hydrodynamic dispersion in the fissures and diffusion and sorption in the rock blocks. 1 and 2D analytical and 3D numerical solutions of the model have been developed. A large number of calculations for the approximate range of variation of the input parameters have been performed. A large impact of hydrodynamic dispersion and micropore diffusion on the amount of radioactive material reaching the biosphere is found.
Linear Zone-Melt Recrystallized Si Films Using Incoherent Light
Authors: Kamgar Avid , Rozgonyi G. A. , Knoell R.
Published: March 2011

Incoherent tungsten radiation has been used to recrystallize polysilicon films deposited on SiO2, grown on 75 mm diameter wafers. These films have been analyzed by a variety of techniques such as optical microscopy, Auger spectroscopy and TEM crosssectioning. These films are large (> 50 mm dia.) single crystals, and contain fewer defects and impurities than similar films recrystallized in graphite strip heater ovens. They do, however, contain the subgrain boundaries found previously, even when high purity Mbe polysilicon is used. In vertical tem cross-sectioning, in addition to the subgrain boundaries,we have seen crystallized particles of 50200 Å size in the si film at both the upper and lower SiO 2 boundaries. Although these particles could be relatedto formation of the subgrain boundaries, no definite correlation has been made.
Hydrothermal Conditions around a Radioactive Waste Repository
Authors: Thunvik Roger , Braester Carol
Published: March 2011

The possibility of permanent burial of radioactive waste from nuclear power plants, is studied in Sweden at the KBS (Nuclear Fuel Safety) - project. Definite repository sites have not yet been selected, but the general principles of construction regarding the layout have been devised (KBS).
Modeling Approach to Determine Short- and Long-Term Thermal and Thermomechanical Effects of Waste Emplacement in a Repository in Basalt
Authors: Lehnhoff Terry F. , Thirumalai K. , Krug Alan D.
Published: March 2011

The Columbia River basalts, which underlie a large portion of the Pacific Northwest of the United States of America, are being investigated as one of the candidate media for a nuclear waste repository. The Basalt Waste Isolation Project (BWIP) of Rockwell Hanford Operations (Rockwell) is conducting these investigations for the U.S. Department of Energy (DOE). Since the inception of the program in 1976, a number of studies have led to the selection of a reference repository location and the start of construction of an exploratory shaft.1-3
Ion/Water Migration Phenomea in Dense Bentionites
Authors: Pusch Roland , Eriksen Trygve , Jacobsson Arvid
Published: March 2011

The development of a suitable technique for isolating unreprocessed nuclear reactor wastes from the biosphere has led to the Swedish multibarrier concept KBS 2 with two engineered ccmponents, a thick-walled copper canister and a clay body which confines the canister, Fig. 1. The clay consists of well fitting blocks of highly compacted Na bentonite made by “isostatic” compression of bentonite powder. They are not water saturated when placed in the deposition holes but take up water from the surrounding rock, swell and ultimately form a tight contact with the rock and the canisters. When the bentonite is in physical equilibrium with the surroundings it forms a medium with a number of valuable properties, such as self-healing and ion exchange capacities. The healing means that initial joints between blocks and voids, or local passages in the clay cased by slight rock or canister displacements, will be sealed by the swelling potential of the clay.
Waste Glass/Repository Interactions
Authors: Clark D.E. , Maurer C.A.
Published: March 2011

The effects of repository material and a tailored backfill or overpack on the leaching behavior of glass have been studied. Two types of glasses were used in this investigation: 1) Model glasses comprised of 33 mol% alkali oxide-67 mol% SiO2 , and 2) alkali borosilicate glasses with and without simulated wastes. Several types of repository material were placed in the same containers as the glasses to determine if their presence would alter the extent of leaching. A backfill material consisting of phosphate slime/sand mixtures was evaluated with the same procedure. The results indicate that the leaching behavior of the glass may be influenced by the presence of some materials. Preliminary results of a 16½ month burial experiment in Florida are also discussed.
Liquid Chromatography in Migration Studies
Authors: Carlsen Lars , Batsberg Walther
Published: March 2011

A detailed knowledge of the geochemical environment of a site for the disposal of radioactive waste is of fundamental importance. To evaluate the migration behaviour of radionuclides in geological media a series of data are needed, amongst others a number of physico-chemical properties of the media, such as permeability, porosity, dispersion-, diffusion-, and sorption characteristics. In this connection liquid chromatography appears to be advantageous as a facile experimental technique to obtain relevant data for these physico-chemical properties.
Potential for the Rapid Transport of Plutonium In Groundwater as Demonstrated By Core Column Studies
Authors: Champ D.R. , Merritt W.F. , Young J.L.
Published: March 2011

The mobility of radionuclides in groundwater flow systems can be significantly altered by processes such as complexation, sorption on particulates, or hydrolysis, precipitation and the formation of colloids. Such processes provide potentially significant pathways for transport of radionuclides in the biosphere. Previous soil column studies demonstrated that radiocesium could be transported by particulates and that the process was likely mediated by micro-organisms. That observation provided a plausible mechanism to explain the anomalously rapid transport of small amounts of cesium-137 released from glass blocks buried below the water table at the Chalk River Nuclear Laboratories.
Properties and Mobilities of Actinide Colloids in Geologic Systems
Authors: Olofsson U. , Allard B. , Torstenfelt B. , Andersson K.
Published: March 2011

The interaction between radionuclides in solution and exposed geologic media, e.g. in connection with underground storage of radioactive waste, is largely determined by the chemical properties of the system. The mobility of radionuclides in contact with low-capacity minerals would depend on the chemical state of the element (e.g. degree of hydrolysis, formation of organic and inorganic complexes, etc.). Particularly for the actinides in their lower oxidation states (III, IV), however, would a formation of colloid particles be feasible in the groundwater environment. These colloids could be either true radiocolloids, i.e. aggregates of the radionuclide itself, or pseudocolloids, i.e. colloid material already present in the groundwater, onto which the radionuclide has sorbed. These colloidal particles may be very poorly sorbed on water exposed geologic media in comparison with radionuclides in true solution. Studies on the formation and properties of some actinide colloids (Am, Np, Pu) are discussed in this paper.
The Migration of Radionuclides with Ground Water. A Discussion of the Relevance of the Input Parameters used in Model Calculations
Authors: Jensen Bror Skytte
Published: March 2011

The plans for the disposal of radioactive waste leave very little time for testing long term performance of a repository so the evaluation of the hazards involved in the operation relies heavily on model calculations. It is therefore of utmost importance that these model calculations take all important parameters into account and are based on a thorough understanding of the possible physical and chemical processes in which the migrating species take part.
Laboratory Tests on the Migration Behaviour of Selected Fission Products in Aquifer Materials from a Potential Disposal Site in Northern Germany
Authors: Behrens H. , Klotz D. , Lang H. , Moser H. , Barke G. , Bruhl H. , Gehler S. , Muhlenweg U.
Published: March 2011

The migration behaviour with respect to retardation by sorption of radioactive Ce, Cs, I, Nb, Ru, Sm, Sr, Tc and Zr in fluviatile and aeolian sand aquifers has been examined in laboratory tests. In these tests it was attempted to simulate the natural conditions of the field. The tests were performed as batch and column experiments. The results of both types of experimental procedures agree within the error limits and show

- small sorption for I− and TcO4−

- medium sorption for Sr2+

- high sorption for Cs+, Ce3+, Sm3+, Ru4+, Zr4+ and Nb5+

The investigations will be continued with other geologic materials from the same site.
A Comparative Analysis Of Fractured and Porous Medium Radionuclide Transport
Authors: Travis B. J. , Nuttall H. E.
Published: March 2011

Modeling of radionuclide transport in geological formations has until recently been limited to the treatment of nonfractured porous media. Recently researchers in Sweden, Canada, France, and the USA have become interested in the problems of nuclide transport in geological formations which may contain fractures. Since many conventional porous-medium ion-transport codes are available, the question arises as to when fracture widths and fracture frequency dictate the use of these existing codes.
In-Situ Solidifcation of Low and Medium Level Wastes
Authors: Kraemer R. , Kroebel R.
Published: March 2011

Since 1976, a German R & D project has been carried out to find an alternative concept for the treatment and disposal of MLW and LLW arisings generated mainly in the planned German reprocessing plant and other nuclear facilities (LWR, fuel fabrication, R & D establishments).
Granules, A New Waste Form For In-Situ Solidification of Low and Medium-Level Waste
Authors: Roguslawski Z. , Dumont E. , Guber W.
Published: March 2011

As already mentioned in the overview paper /1/ the in-situ solidification process requires a preconditioning of MLW/LLW arisings by granulation. The main purpose thereof is the dissipation of the heat of hydration already above ground and to replace in the final concrete like waste form a considerable part (i.e. 60 vol.%) with inert granules.
Transport of Waste Into Caverns By Vertical Flow Of Concrete Suspensions
Authors: Weber M. , Dedegil Y. , Homann H. H.
Published: March 2011

In the process described in the first paper of this session for containerless final storage of radioactive wastes, a granule-cement suspension (waste grout) is transported by means of a vertical pipe from above ground into the underground cavern.
High-Temperature Dielectric Properties of Polycrystalline Ceramics
Authors: Ho W. W.
Published: March 2011

Experimental methods for determining the high-temperature millimeter-wave dielectric properties of solids are described and the data obtained on a wide variety of polycrystalline ceramics are reviewed. In general, the observed increase in dielectric constants with temperature can be modeled with a macroscopic dielectric virial expansion and shown to be primarily caused by an increase in polarizability due to volume expansion. The room-temperature loss tangents in low-absorption ceramics are probably caused by impurity doping of the primary and secondary crystalline phases at grain junctions and along grain boundaries. The rapid increase in loss tangent at high temperatures commonly observed in polycrystalline ceramics is associated with softening of intergranular amorphous phases resulting in an increase in localized electrical conductivity.
Applications of Microwave Energy Past, Present and Future “Brave New Worlds”
Authors: Chabinsky Irving J.
Published: March 2011

The 20th century can be called the Age of Technology and during the last 40 years the technology has doubled every 10 years, and microwave energy is one of the technologies. The utilization of microwave energy for the generation of heat was discovered accidentally during testing of magnetrons at the Microwave & Power Tube Division of Raytheon in 1950.
Measurement of the Absorption of Microwave Power by Corroded Metals
Authors: Bruce Ralph W. , Quar R. A.
Published: March 2011

Metal alloys, when exposed to a salt/organic environment at elevated temperatures, corrode resulting in a decrease in the surface conductivity. This decrease can be monitored and assessed via the measurement of the incident and reflected microwave signals impinging upon the corroded surface. Several metallic alloys, stainless steels and inconels, were treated with a salt/organic mixture (proprietary) and heat treated at 1100 F. Periodically, the metals were removed from the furnace, allowed to cool to room temperature, and measured electrically. The samples were re-coated with the salt/organic mixture and re-heat treated. The electrical measurements showed a generally increased power absorption as corrosion thickness increased.
Microwave Sintering of Ceramics Under High Gas Pressure
Authors: Tian Yong-Lai , Brodwin Morris E. , Dewan Hardial S. , Johnson D. Lynn
Published: March 2011

During microwave sintering of ceramics, the input microwave power and specimen temperature are limited by the breakdown of the gas in the cavity. The ionization potential of the gas, the temperature, and the specimen shape are all factors that influence the onset of breakdown. Thus, in the sintering of SiC rods in a TE111 cylindrical cavity at 1 atm argon or nitrogen, breakdown occurred at temperatures less than 1300 C and 1700 C, respectively, which are well below the required sintering temperature.

Breakdown can be suppressed by applying either high vacuum or high pressure. Sintering in high vacuum would exacerbate the problems of decomposition and vaporization of ceramics such as Si3N4 and SiC at high temperatures. Pressurization not only suppresses breakdown but inhibits decomposition and vaporization.

The TE111 cylindrical cavity has been adapted for pressurization to 1.38 MPa. The allowable input microwave power and specimen temperature have been markedly increased under high pressure conditions.
Microwave Processing at Ontario Hydro Research Division
Authors: Oda S. J. , Balbaa I. S.
Published: March 2011

Ontario Hydro has established a Process Applications Laboratory dedicated to helping industry apply electrotechnologies for a variety of processes. Demonstration and development of industrial microwave applications are being conducted to provide an important interface between the industrial user and microwave equipment manufacturer. Curing, heating, tempering, sintering, calcining and drying are among the operations that have been successfully demonstrated on a wide range of products including polymers, ceramics, composites, paper and wood products, food, pharmaceuticals and textiles. The benefits of microwave heating are illustrated with examples of feasibility studies performed for manufacturers and a R&D project being conducted in-house.
Structural Adhesive Curing for Bonding Composites, Thermosets and Thermoplastics
Authors: Rains Randall C.
Published: March 2011

The bonding of composites, thermosets, and thermoplastics via microwave energy is not only technically feasible but economically viable compared to conventional technologies.

In recent years the growth in the use of composites, thermosets and thermoplastics has demonstrated the ability of these materials to fulfill specific performance needs in the automotive sector. In a contrary fashion the increased demand has served to focus attention on those factors which mitigate against further growth. In many instances this becomes a discussion of cycle times in primary or secondary operations.
Fundamentals of Microwave-Material Interactions and Sintering
Authors: Tinga Wayne R.
Published: March 2011

Basic interaction mechanisms are shown to depend strongly on the dielectric and magnetic properties of a process material. This causes a strong dependence of power absorption on frequency, material particle size, shape, temperature, and density. Sintering dynamics cause the microstructure of the treated material to change resulting in a change in microwave (1W) heating uniformity and rate. The concept of dielectric mixtures is introduced to predict the dielectric and heating properties of a host material with its inclusions in the form of shells, ellipsoids, spheres, disks and needles. Simplified models are described to give a process designer some insight into the behavior of MW sintering. Microwave power, by its very nature, gives better heating control and efficiency and provides internal heat to aid the material transport during sintering. No inherent temperature limit exists for MW sintering although refractory materials used to contain the process material create an artificial upper limit. It is shown that very high (1500–2000°C) temperatures in small samples can be readily achieved using commercial microwave ovens if appropriate MW transparent sample holders are used.
Economic Assessment of Microwave and Radio-Frequency Materials Processing
Authors: Sanio Michael R. , Schmidt Philip S.
Published: March 2011

Dielectric heating has clearly demonstrated its production benefits in many materials processing applications. It is, however, a relatively expensive technology and its use vis a vis less expensive alternatives must be justified by a thorough economic analysis of all factors relevant to the given application. These include not only direct production costs, but also less easily quantified “implicit” factors such as product quality, reduced impact on the external environment, and improved workplace environment.

An economic model which includes both production cost considerations and implicit factors in dielectric heating applications is under development. This paper will focus on the capital and operating costs of dielectric heating equipment and the factors which influence these costs. Capital and operating cost information was obtained from radio-frequency and microwave suppliers and consultants in the United States. Mail-out questionnaires were followed up by extensive telephone discussions to correlate and clarify data. The intent was to identify the major cost components of dielectric heating equipment and to summarize the qualitative and quantitative factors which affect them. Since microwave and radio-frequency equipment are distinctly different in design and application, they are treated separately.
Precision Microwave Applicators and Systems for Plasma and Materials Processing
Authors: Asmussen Jes , Garard Richard
Published: March 2011

Modern applications of microwave energy have imposed new requirements upon microwave processing systems. Interest in energy efficiency, processing uniformity and control of process cycles has placed new design conditions upon microwave power oscillators, microwave systems and microwave applicator design. One approach of meeting new application requirements is the use of single-mode or controlled multimode applicators. The use of a single-mode applicator for plasma generation and materials processing will be presented. Descriptions of actual applicator designs for heating, curing and processing of solid materials and the generations of high and low pressure discharges will be given. The impact of these applicators on the total microwave system including the microwave power source will be described. Specific examples of applicator and associated microwave systems will be detailed for the applications of (1) plasma thin film deposition and (2) the precision processing and diagnosis of materials. Methods of process control and diagnosis, control of process uniformity and process scale up are discussed.
A Versatile Microwave Plasma Applicator
Authors: Ji Tian-Ren , Gerling John E.
Published: March 2011

This paper describes a device used for the introduction of microwave energy into a plasma chamber over a wide area with high
transfer efficiency and good energy uniformity.

The applicator design was based on a slotted waveguide combined with a quartz window. The impedance properties were calculated for
slots in the broad wall of WR430 waveguide. Low power simulating tests were conducted to determine the optimum geometry. A simple
test system was used to measure and plot the three-dimensional spatial energy distribution
Advanced Microwave Technology
Authors: Edgar Richard H.
Published: March 2011

The importance of developing systems that are safe and reliable as well as high performance is discussed and emphasized. The nature of current safety standards for interference and personnel safety are described. Several systems from industries such as food and rubber are described with a focus on safety and reliability issues.
Microwave Sintering of Ceramics
Authors: Varadan Vuay K. , Ma Yushieh , Lakhtakia Akhlesh , Varadan Vasundara V.
Published: March 2011

Theoretical considerations regarding microwave sintering of ceramics are discussed. It is shown how the rigorous application of multiple scattering theory may permit a better understanding of this interesting process. The possibility of thermal runaway being chaotic is discussed. Experimental results, and a possible connection to percolation theory, are also given.
Principles of Microwave Interaction with Polymeric and Organic Materials
Authors: Varadan Vijay K. , Varadan Vasundara V. , Lakhtakia Akhlesh
Published: March 2011

Electromagnetic waves can discriminate between objects of different handedness due to their transverse nature, which implies that the origin of chirality need not necessarily be molecular as in the case of optically active media. Effectively chiral composites may, therefore, be constructed by embedding chiral microstructures in non-chiral host media.
Medical and Biological Applications of Electromagnetic Techniques – a Relevant Experience to the Microwave Processing of Materials Research
Authors: Iskander Magdy F.
Published: March 2011

The feasibility of using electromagnetic (EM) energy in industrial, medical, or in biological applications relies heavily on accurate knowledge of the dielectric properties of materials and on detailed understanding of the underlying interaction mechanisms. This chapter deals with the medical and biological applications of EM radiation. It therefore starts with a brief review of the dielectric properties of various tissues and a description of some of the basic interaction mechanisms. The techniques used to measure these properties are of particular interest to the microwave processing of materials research. Therefore, some of the time- and frequency-domain measurements methods of the dielectric properties of materials are discussed.

Available techniques for calculating and measuring the absorption of EM radiation by humans and other biological models are also described. The impact of the obtained EM dosimetry results on modifying the ANSI Safety Standard is outlined. It will be noted that many of the dosimetric measurements procedures are highly relevant to experiences in the microwave processing of materials research.

In addition, some of the medical applications in both the diagnostics and therapeutic areas are described. These applications basically exploit some of the unique dielectric characteristics of biological tissues. Specifically, noninvasive and interstitial EM hyperthermia techniques for cancer treatment are discussed, and other potential microwave methods for medical diagnostics are briefly reviewed. Future research needs to further the understanding of the various interaction mechanisms of EM radiation with materials are outlined. Every effort is made to relate experiences in the medical and biological research areas to research in the microwave processing of materials.
Impurity Redistribution In Ion Implanted Si After Picosecond Nd Laser Pulse Irradiation
Authors: Campisano S.U. , Baeri P. , Rimini E. , Russo G. , Malvezzi A.M.
Published: March 2011

Impurity redistribution in Bi-implanted Si and in As-implanted Si has been investigated after irradiation with 25 ps Nd(λ=l.06 μm) laser pulse in the energy range 0.1–1.5 J/cm2 . Channeling effect in combination with 2.0 MeV He+ backscattering in glancing detection has been used to characterize the epitaxial crystallization, the impurity location and its depth distribution. The amorphous to single crystal transition occurs at an energy density of about 0.4 J/cm 2 . Bi atoms are located after crystallization in substitutional lattice sites for the in depth part of the distribution. Part of the Bi atoms accumulated at the sample surface and the amount of segregation increases with the pulse energy density and depends on the substrate orientation. A computer model has been also developed to calculate several parameters of interest, as the melt threshold,the melt duration, the carrier temperature etc including a detailed description of the absorption and of the energy relaxation processes. The calculations indicate that the simple thermal description accounts quantitatively for the experimental data on melt duration and impurity segregation.
Dopant Incorporation During Rapid Solidification
Authors: White C. W. , Zehner D. M. , Narayan J. , Holland O. W. , Appleton B. R. , Wilson S. R.
Published: March 2011

Incorporation of Group III, IV, V dopants in silicon occurs as a result of solute trapping during laser annealing. Distribution coefficients and substitutional solubilities are far greater than equilibrium values, and can be functions of growth velocity and crystal orientation. Mechanisms limiting dopant incorporation at high concentrations are identified and discussed.