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Al2O3-based ceramic is one of the most widely used materials for tools employed in hardened steel turning applications due to its high hardness, wear resistance, heat resistance and chemical stability. The objective of this work is to predict the lives of Al2O3-(W, Ti)C ceramic tools in intermittent turning of hardened AISI 1045 steel by means of damage evolution model taking into account the mechanical loading and thermal effect in the cutting process. A damage evolution model analyzing the RVE with uniformly distributed interacting cracks is constructed based on micromechanics. The calculated results of the proposed damage evolution model are compared with the lives of two kinds of Al2O3-(W, Ti)C ceramic tools obtained through experiments. It is found that the proposed model can be used to predict the lives of the ceramic cutting ...

International Nuclear Information System (INIS)

Advanced structural ceramics are presently used in several tribological applications, such as precision instrument bearings, automotive engine parts and cutting tools inserts. Design and selection of advanced ceramics for these applications require reliable data on the effects of temperature, load and environment on the tribological behaviour of these materials. In the present work, the friction and wear behaviour of colloidally processed and pressureless sintered sialon ceramics with phase (#alpha#) have been studied, aiming at increasing #alpha#-sialon in industrial applications as cutting tools. The friction and wear behaviour of sialon ceramics against steel DIN-Ck45K were investigated using a pin-on-disk tribometer under dry sliding conditions at room temperature, in order to eliminate the contribution of lubricant. The experiments were performed with a ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Aims: To develop a new nano composite of multi walled carbon nanotubes (MWNTs) with enhanced antimicrobial activity. Methods and Results: A novel antimicrobial nanocomposite [MWNT epilson polylysine (MEPs)] was synthesized via covalent attachment of epilson polylysine on MWNTs with hexamethylene diisocyanate (HDI) as the coupling agent. UV visible spectra and Fourier transform infrared spectra (FT IR) investigations indicate that MEPs is stable, with epilson polylysine leaching effectively eliminated. When compared to MWNTs, the new nano composite MEPs exhibits enhanced antimicrobial activities. In 20 mg l 1 suspensions, significant increases of 72 1, 64 5 and 69% against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus can be observed. The deposited film of MEPs...

Energy Technology Data Exchange (ETDEWEB)

A porous tooling system was selected for the processing of Graphite/PMR-15 Polyimide laminates in thickness up to 3.2 mm. (0.125 inch). This tool system must have a reasonable strength, permeability dimensional stability, and thermal conductivity to accomplish curing at 600 F and 200 psi and 200 psi autoclave temperature and pressure. A permeability measuring apparatus was constructed and permeability vs. casting water level determined to produce tools at three different permeability levels. On these tools, laminates of 5, 11, and 22 plies (.027, .060, and 0.121 inch) were produced and evaluated by ultrasonic, mechanical, and thermal tests to determine the effect of the tool permeability on the cured laminates. All tools produced acceptable laminates at 5 and 11 plies but only the highest permeability produced acceptable clear ultrasonic C-Scans. Recommendations ...

International Nuclear Information System (INIS)

This paper deals with preparation of PE clay nano composite specimen for transmission electron microscopy (TEM) and studying the difference between dispersion of clay in low density polyethylene using poly(hydrogen methyl siloxane) (PHMS) as coupling agent and untreated one. Argon ion milling is the conventional means by which film sections are thinned to electron transparency for TEM analysis, but this technique exhibits significant problems. In particular, selective thinning and imaging of sub-micrometer inclusions during sample milling are highly problematic. We have achieved successful results using the focused ion beam (FIB) lift-out technique, which utilizes a 30 kV Ga"+ ion beam to extract electron transparent specimens with nanometer scale precision. Using this procedure, we have prepared a number of thin film materials representing a range of structures and compositions for TEM analysis. We believe that FIB milling will create major ...

International Nuclear Information System (INIS)

Conductive TiN/Si_3N_4 ceramic composites were processed by electrical discharge machining (EDM) and their microstructure and conductivity were investigated. The whole process of tool electrode wear is evaluated by sinker-EDM. The machined surfaces of TiN/Si_3N_4 ceramic composites were examined by scanning electron microscopy (SEM) and profilometry to determine the surface finish. The electrode wear rate of brass is higher than copper electrode for all EDMed tests. The surface texture was found to have greater dependence on pulse energy. It was observed that the sinker-EDM at higher pulse energy caused severe microdamage in the surface. The surface roughness (Ra) values also increase with increasing pulse energy.

International Nuclear Information System (INIS)

Direct electrochemistry and electrocatalysis of catalase (Cat) was studied based on a nano-composite film consisting of amine functionalized graphene and gold nanoparticles (AuNPs) modified glassy carbon electrode. Graphene was synthesized chemically by Hummers and Offeman method and then was functionalized with amino groups via chemical modification of carboxyl groups introduced on the graphene surface. The nano-composite film showed an obvious promotion of the direct electron transfer between Cat and the underlying electrode, which attributed to the synergistic effect of graphene-NH2 and AuNPs. The resultant bioelectrode retained its biocatalytic activity and offered fast and sensitive H2O2 quantification. Under the optimized experimental conditions, hydrogen peroxide was detected in the concentration range from 0.3 to 600 ?M with a detection limit of 50 nM at S/N = 3. The biosensor exhibited some advantages, such as short time respond (2 s), ...

CERN Document Server

PLZT Ceramics Prepared from Conventional and Microwave Hydrothermal Powders

International Science & Technology Center (ISTC)

Development of Ceramic Composite Materials and Structural Elements for High-Temperature Nuclear Reactors

British Library Electronic Table of Contents (United Kingdom)

The present study is focused on preparation of nano composite materials and the effect of citric acid on their different properties. The formation of nano HA and its interaction with chitosan (C), gelatin (G) polymers and citric acid (CA) materials were studied. The Fourier Transformed Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), transmission electron microscope (TEM), and scanning electron microscope (SEM) were used to characterize these composite materials. The compressive strength (CS) was also measured to know the reinforcement of the prepared composites. The results show that carboxylic and amino groups play crucial role for HA formation on chitosan-gelatin polymeric matrix in the presence of citric acid (CA). The formation of nano HA part...

Science.gov (United States)

A system for inspecting a ceramic component. The ceramic component is positioned on a first rotary table. The first rotary table rotates the ceramic component. Light is directed toward the first rotary table and the rotating ceramic component. A detector is located on a second rotary table. The second rotary table is operably connected to the first rotary table and the rotating ceramic component. The second rotary table is used to move the detector at an angle to the first rotary table and the rotating ceramic component.

Science.gov (United States)

... The data were transformed into total hemispherical emittance values and correlated with respect to ceramic coating thickness and temperature ...

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This paper introduces a new method to produce nano-composite powder for the preparation of high performance ZnO varistors. ZnO particles were coated with Bi{sub 2}O{sub 3}, Sb{sub 2}O{sub 3}, Co{sub 2}O{sub 3}, Cr{sub 2}O{sub 3} and other additives via liquid nano-coating technique. Then the prepared powder was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravity and differential scanning calorimetry (TG-DSC) and particle size distribution. The results showed that the ZnO composite powder is homogeneously coated and ultrafine. The densification, phase composition and microstructure of ZnO varistors was studied by linear shrinkage, X-ray diffraction (XRD) and SEM, respectively. The preliminary electrical parameters of ZnO varistors showed that the breakdown voltage V {sub b} (1 mA/cm{sup 2}) and nonlinear coefficient {alpha} is 5400 V/cm and 50, respectively, much higher than that of conventional ball milling ...

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... 300710+Ceramic+Transactions+Series 2120%28Series+Code%29+Ceramic+Transactions+Series Wiley::Ceramic Transactions Series WILEY KNOWLEDGE FOR GENERATIONS United States Change Location Home ...CART | MY ACCOUNT | CONTACT US | HELP Home / Engineering & Materials Science / Materials Science / Ceramic Transactions Series Related Subjects Soft Matter Organic Electronics Structural Materials, ... Ceramics Structural Materials, Composites Structural Materials or Construction Materials Corrosion Electronics Materials Related Series Ceramic Engineering and Science Proceedings Wiley Series in Materials ...for Electronic and Optoelectric Applications Ceramic Transactions (CTs) books contain papers presented at the Annual Meeting of the American Ceramic Society, ...

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Effect of alcohol solvent in mixing process on process on the microstructure and sintering behavior of ceramic-based composites was inestigated in detail. The mixture of fine ceramic powders was prepared through the conventional ball-milling method with various alcohol media. The particle distributions of fine ceramic powders were strongly dependent on the kind of alcohol employed during ball-milling. Ceramic-based composites were fabricated by hot-pressing the mixture of fine ceramic powders. Their microstructures and some mechanical properties of the ceramic-based composites were evaluated. It was found that the viscosity of alcohol, surface tension and contat angle greatly affect the sinterbility and some of the mechanical properties of ceramic-based somposites. (author)

Science.gov (United States)

A novel reactor combining a flame-deposited nanostructured titanium dioxide film and a set of embedded ceramic electrodes was designed, developed and tested for degradation of methyl tert-butyl ether (MTBE) in water. On applying a voltage to the ceramic electrodes, a surface coro...

Science.gov (United States)

Courses in Ceramic Engineering from the Course Catalog at the University of Illinois at Urbana-Champaign. List includes: CER E 299. Senior Thesis CER E 320. Ceramic Materials and Properties CER E 321. Ceramic Processing and Microstructure Development CER E 322. Process Design CER E 323. Ceramic Engineering Processing Laboratory CER E 324. Refractory Technology CER E 326. Chemistry and Technology of Glass CER E 327. Ceramic Microscopy CER E 328. Electrical Ceramics CER E 330. Chemically Bonded Ceramics CER E 390. Special Topics in Ceramics CER E 420. Ceramic Chemistry CER E 422. Dielectric Properties of Ceramic Materials CER E 425. Physical Chemistry of Clays and Soils CER E 426. Mineralogy of Clays CER E 427. Petrology of Clay Minerals CER E 429. Seminar in ...

Science.gov (United States)

International Patenting Trends in Advanced Materials: Ceramics (June 18, 1999) This report is the ... manufacturing, biotechnology, and advanced materials. Hypertext Format Portable Document Format ...

Energy Technology Data Exchange (ETDEWEB)

In addition to ceramics, alloys such as tool steel and nickel- and iron-based superalloys are being considered for high temperature applications such as missile bearings and low heat rejection engines. Studies were made to lubricate a nickel-based superalloy at 500{degrees}C, by using a vaporized aryl phosphate ester, at a concentration of 0.1% in air. From deposition and wear studies it was found that it was impossible to form a good polymeric coating on the superalloy surface. Energy dispersive X-ray analyzer (EDXA) analysis showed that this was due to minute quantities of aluminum in the alloy segregating to the surface, upon being heated to 500{degrees}C, forming a passive oxide coating. It was necessary to activate the surface, in order to lubricate the material successfully. A method of activation by electrodepositing the surface with a layer of iron oxide was developed. Once activated, a good lubricous polymer was formed on the ...

Energy Technology Data Exchange (ETDEWEB)

Small angle neutron scattering (SANS) has been a very powerful tool to study nanoscale (1-100 nm) bulk structures in various materials such as polymer, self assembled materials, nano-porous materials, nano-magnetic materials, metal and ceramics. Understanding the importance of the SANS instrument, the 8m SANS instrument was installed at the CN beam port of HANARO in 2001. However, without having a cold neutron source, the beam intensity is fairly low and the Q-range is rather limited due to short instrument length. In July 1, 2003, therefore, the HANARO cold neutron research facility project was launched and a state of the art 40m SANS instrument was selected as top-priority instrument. The development of the 40m SANS instrument was completed as a joint project between Korea Advanced Institute of Science and Technology and the HANARO in 2010. Here, we report the specification of a state of art 40m SANS instrument at HANARO

KoreaScience (Korea)

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Stress relaxation was studied at 408 K on AZ31 reinforced by ceramic foam produced by in situ foaming of filler loaded preceramic polymer melt. Reinforcement causes significant enhancement of the resistance against stress relaxation compared to AZ91. It is correlated with hardening by the ceramic skeleton as well as ceramic particles formed in the AZ31-matrix. (orig.)

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Language: English ...

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A set of materials property data for potential wear resistant materials was collected. These materials are designated for use as the ''core'' materials in the Fibrous Monolith structure. The material properties of hardness, toughness, thermal conductivity and cost were selected as determining factors for material choice. Data for these four properties were normalized, and weighting factors were assigned for each property to establish priority and evaluate the effects of priority fluctuation. Materials were then given a score based on the normalized parameters and weighting values. Using the initial estimates for parameter priority, the highest ranking material was tungsten carbide, with diamond as the second ranked material. Several materials were included in the trade study, and five were selected as promising ''core'' materials to include in this effort. These materials are tungsten carbide, diamond, boron ...

British Library Electronic Table of Contents (United Kingdom)

Statement of problem Porcelain fracture associated with an implant-supported, metal ceramic crown or fixed partial denture occurs at a higher rate than in tooth-supported restorations, according to the literature. Implant-specific and patient-specific causes of ceramic failure have not been fully evaluated. Purpose The purpose of this retrospective study was to evaluate the potential statistical predictors for porcelain fracture of implant-supported, metal ceramic restorations. Material and Methods Over a 6-month period, a consecutive series of patients having previously received implant-supported, metal ceramic fixed restorations were examined during periodic recall appointments. The number of supporting implants, number of dental units, type of restoration, date of prosthesis insertion, ...

Energy Technology Data Exchange (ETDEWEB)

In this, the last of a series of three papers, we discuss a method of forming iron phosphate ceramics by a reduction process. We report the formation of iron oxide ceramics by reducing hematite with iron in a phosphoric acid solution. The reaction results in a rapid-setting ceramic (at room temperature) with a compressive strength of 3700 psi and a density of 1.7 g/cm{sup 3}. Although the exact mineral form of the binder is difficult to determine because it is mostly amorphous and hence is not amenable to X-ray diffraction analyses, this material is expected to consist of iron hydrophosphates. The reduction process is very useful in recycling several industrial wastes that are rich in hematite, including iron mine tailings, red mud (a caustic waste from the alumina industry), and machining swarfs. Formation of ceramics with red mud and swarfs is also discussed.

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The Co-doped BaTiO{sub 3} nanosized powders and ceramics were prepared via the sol-gel process. The powders and ceramics were characterized by methods of XRD, SEM and TEM. The dielectric properties of the ceramics were also determined by these methods. The influence of sintering temperature, sintering time and Co concentration on the microstructure and dielectric properties was discussed. The results revealed that the powders were in nanometer scale (30-50 nm) and were mainly composed of cubic BaTiO{sub 3} phase and small amount of BaCO{sub 3}. After sintering, both the cubic BaTiO{sub 3} and BaCO{sub 3} were transformed into tetrahedron BaTiO{sub 3}. The sintering temperatures of the Co-doped BaTiO{sub 3} ceramics decreased (about 100 deg. C) and the Curie temperatures of the ceramics were then moved to lower temperature. In addition, the dielectric constant of the ...

Energy Technology Data Exchange (ETDEWEB)

In order to design the microstructure of ceramics with desired dielectric property, an estimation method of dielectric constant of ceramics taking into account the characteristics of microstructure of the ceramics is proposed. In the estimation model, the microstructure of ceramics is represented by the assembly of unit cells comprising of grain, pore and grain boundary. The sizes of grain and pore and the thickness of grain boundary in each unit cell were determined exactly according to their size and thickness distributions in a real ceramic. The dielectric constant of the assembly can be calculated on the basis of equivalent circuit theory. The estimated values of dielectric constant of ceramic BaTiO{sub 3} using the proposed estimation method agree well with experimental ones. The dependence of characteristics of microstructure on the dielectric constant was ...

Science.gov (United States)

... Accession Number : ADA539462. Title : 6.5 kW, Yb:YAG Ceramic Thin Disk Laser. Descriptive Note : Technical note 1 Jan-1 Dec 2010. ...

International Science & Technology Center (ISTC)

Development of SHS-technologies for SiC, Si3N4 and Ceramic Composites on Their Basis from Rocks

International Nuclear Information System (INIS)

English Mar 1999 [vp.] United Kingdom Jumali, MHH Warwick Univ.,

Science.gov (United States)

... 1 ..... 14 High Dielectric Constant Ceramics for Use in Blumlein Transmission Lines ..... 14 ...

Medline Plus

... energy. It consists of a stack of piezoelectric ceramics sandwiched under high pressure between two metal cylinders. ...

Wastenet

Labeling of organic res- taurants, cantinas, etc.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

The following methods of quartz ceramics alloying were considered: alloying of initial quartz glass; introduction of alloying additive into water slip of quartz glass; porous materials impregnation with salt aqueous solutions and subsequent salt thermal decomposition with formation of stable oxides in pores of ceramics. Oxygen free compounds BN, SiB_4, SiC, Si_3N_4, REM oxides and transition metal oxides were used as alloying additives. Main properties of the materials and compositions obtained are presented.

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An advanced ceramic dome cavity receiver is discussed which heats pressurized gas to temperatures above 1800/sup 0/F (1000/sup 0/C) for use in solar Brayton power systems of the dispersed receiver/dish or central receiver type. Optical, heat transfer, structural, and ceramic material design aspects of the receiver are reported and the development and experimental demonstration of a high-temperature seal between the pressurized gas and the high-temperature silicon carbide dome material is described.

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This document contains a listing of the written scientific information originating in the Materials Joining (formerly the Welding and Brazing Group), Metals and Ceramics Division, Oak Ridge National Laboratory during 1951 through June 1989. This registry of documents is as much as possible, in the order of issue date. A complete cross-referenced listing of the technical literature of the Metals and Ceramics Division is also available.

Science.gov (United States)

"Precision manufacture of ceramic parts with CNC machining capability for aerospace, lasers, semiconductors and other industries. Materials include alumina, zirconia, glass, ferrites, silicon carbide, silicon nitride, sapphire, cordierite, mullite and others. A.C.T. has seen the number of applications and demand for high-realiability ceramics (aluminum oxide, zirconia, glass, ferrites, silicon carbide, silicon nitride, sapphire, cordierite, mullite, etc...) increase continually within the aerospace, computer and the industrial markets."

Energy Technology Data Exchange (ETDEWEB)

The purpose of the workshop was to determine the status of the field, to define instrumental and computational requirements, and to establish minimum specifications required by possible users. The most important message sent by implementers was the remainder that CMT is a tool. It solves a wide spectrum of scientific problems and is complementary to other microscopy techniques, with certain important advantages that the other methods do not have. High-resolution CMT can be used non-invasively and non-destructively to study a variety of hierarchical three-dimensional microstructures, which in turn control body function. X-ray computed microtomography can also be used at the frontiers of physics, in the study of granular systems, for example. With high-resolution CMT, for example, three-dimensional pore geometries and topologies of soils and rocks can be obtained readily and implemented directly in transport models. In turn, these geometries can be used to calculate ...

British Library Electronic Table of Contents (United Kingdom)

Statement of problem Computer-aided design/computer-aided manufacturing (CAD/CAM) titanium ceramic restorations were developed with the potential for replacing expensive, high noble metal ceramic restorations. However, there is a lack of information about the clinical performance of CAD/CAM titanium ceramic single crowns. Purpose The purpose of this study was to evaluate CAD/CAM titanium ceramic single crowns after 3 years in function. Material and methods A total of 41 crowns were fabricated for 21 patients. The titanium copings were CAD/CAM milled (Everest CAD/CAM system) with an even thickness of 0.5 mm, and low-fusing veneering porcelain (Vita Titanium Porcelain) was added incrementally. The crowns were cemented using zinc phosphate cement after confirming that there were no mechanical...

British Library Electronic Table of Contents (United Kingdom)

Statement of problem Although the esthetic outcome of a collarless metal ceramic restoration is superior to that of a restoration with a metal margin, its mechanical strength has not been evaluated. Purpose The purpose of this study was to evaluate and compare the fracture resistance of metal ceramic restorations with metal margins to that of metal ceramic restorations with circumferential porcelain margins, after exposure to masticatory simulation. Material and methods Twenty-four metal ceramic restorations were fabricated and paired with 24 cobalt-chrome tooth analogs. Twelve of the specimens had metal margins, while the remainder had circumferential porcelain margins. The restorations were cemented on the metal tooth analogs with a resin-modified glass ionomer luting agent (FujiCEM). Al...

International Nuclear Information System (INIS)

Interest in making complex net-shape ceramic parts with good surface finishing and sharp tolerances without machining is a driving force for studying the injection molding technique. This method consists of softhening the ceramic material by means of adding some plastic and heating in order to inject the mixture under pressure into a relatively cold mold where solidification takes place. Essentially, it is the same process used in thermoplastic industry but, in the present case, the ceramic powder load ranges between 80 to 90 wt.%. This work shows results obtained from the fabrication of pieces of different ceramic materials (alumina, barium titanate ferrites, etc.) in a small scale, using equipments developed and constructed in the laboratory. (Author).

Energy Technology Data Exchange (ETDEWEB)

For rational use of energy resources, the process technology which allows harmonization and multiplication of conflicting characteristics was developed for development of new ceramic system materials. This paper summarizes the result in fiscal 1997. On a structural reaction process among creation technologies of ultra-reliable structure, study was made on structure control and hot-working technology through atmosphere control in ceramics synthesis. On basic technology for analysis and evaluation, study was made on the effect of particle bridging on strengthening and toughening of ceramic materials. Study was also made on a toughness expression mechanism, FEM model analysis of particle bridging, and crack growth resistance of ceramics. On control of solid solution precipitation, new alumina ceramics with high strength, hardness and wear resistance was obtained by transgranularly ...

Energy Technology Data Exchange (ETDEWEB)

For several decades most of the efforts to develop new scintillator materials have concentrated on high-light-yield inorganic single-crystals while polycrystalline ceramic scintillators, since their inception in the early 1980 s, have received relatively little attention. Nevertheless, transparent ceramics offer a promising approach to the fabrication of relatively inexpensive scintillators via a simple mechanical compaction and annealing process that eliminates single-crystal growth. Until recently, commonly accepted concepts restricted the polycrystalline ceramic approach to materials exhibiting a cubic crystal structure. Here, we report our results on the development of two novel ceramic scintillators based on the non-cubic crystalline materials: Lu SiO:Ce (LSO:Ce) and LaBr:Ce. While no evidence for texturing has been found in their ceramic microstructures, our LSO:Ce ...

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Design tools that are currently available for use with microcomputers to assist in designing energy-efficient daylighted buildings are presented. The information presented was gathered as a part of a telephone survey to design tool developer conducted over a six month period. The matrix is but one of five categories of tools. The other four were nomographs, protractors/tables, minis, and main frame computer programs. Information is provided to encourage interested design professionals, educators and students to communicate directly with design tool representatives.

Energy Technology Data Exchange (ETDEWEB)

The industrial policy of fine ceramics which is one of the new material expected to solve energy/environmental problem, is described. Fine ceramics are possessed with the characteristics like surpassing electromagnetic properties, heat resistance, high strength, etc. and its use as highly efficient power generation plant material, functional material for various sensors/electronic, and activation of existing industries are cited. As for the reclamation of global environment, promotion of saving energy in a global scale, development of innovative environmental technology and increase of carbon dioxide absorption source are described. Furthermore, research and development work in Japan on global environmental industrial technology for 1992 to 1993, new sunshine project and technical developments relating to fine ceramics are explained. As for the results of research and development, the results from the case study of 300kw ...

Energy Technology Data Exchange (ETDEWEB)

This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Functionally graded material is an enabling technology for lightweight body armor improvements. The objective was to demonstrate the ability to produce functionally graded ceramic-polymer and ceramic-metal lightweight armor materials. This objective involved two aspects. The first and key aspect was the development of graded-porosity boron-carbide ceramic microstructures. The second aspect was the development of techniques for liquid infiltration of lightweight metals and polymers into the graded-porosity ceramic. The authors were successful in synthesizing boron-carbide ceramic microstructures with graded porosity. These graded-porosity boron-carbide hot-pressed pieces were then successfully liquid-infiltrated in vacuum with molten ...

International Nuclear Information System (INIS)

The paper presents results of measurements of the natural radioactivity of tap water where samples were taken in front of, and behind the ceramic filter commonly used in houses for the purification of tap water. Altogether, 289 samples were taken, processed and measured during 1985-1986 in Kuwait. Results reveal the fact that ceramic filters reduce substantially the natural radioactivity in water (the 'gross' alpha activity reduced by the factor 2.18 #+-# 18%; the 'gross' beta by 1.53 #+-# 1.6%. (author).

International Nuclear Information System (INIS)

The fabrication of the ZT-40 torus, a large complex all-ceramic toroidal plasma containment vessel, is described. Several glass sealants covering the temperature range of 500 to 1300"0C, were developed and used to ''braze'' segments of the torus together, sapphire windows to the torus and the required pump-out and diagnostic parts to the ceramic vacuum vessel. Designs of window seals were developed that allowed sealing of the sapphire windows in a vertical position with minimum sealing glass flow.

International Nuclear Information System (INIS)

Monolithic SiAlON ceramics are hard and brittle with little possibility for property design, but multi-phase SiAlON ceramics offer great scope for controlling microstructural development and desired properties. The ceramics can also be reinforced by separate additions of other hard, refractory compounds. The toughness in all these SiAlON composites can be increased by several mechanisms, and the best effect is reached if they are combined. When glassy phase is present, crack paths are affected by the strains caused by different thermal expansion of the glassy phase and the crystals and also by the interface properties. The crystal shape influence toughness, especially pronounced is the effect of the elongated #beta#- grains. Different toughening mechanisms are achieved by separately added reinforcement phases. The hardness is raised by the presence of #alpha# SiAlON and other hard constituents, such as SiC. (orig.).

Science.gov (United States)

Not Available

Energy Technology Data Exchange (ETDEWEB)

In the present study, element interdiffusions at the cofired interface of 9/1 Ag/Pd electrode and lead magnesium niobate (PMN)-based ferroelectrics were investigated using Auger Electron Spectroscopy (AES). Intense interdiffusions at the interface were observed while Ag and Pd could penetrate into the ceramics for about 1 {mu}m. Ag-doping experiments were carried out to further study the effects of Ag diffusion on electrical properties of the ceramics. The results showed that Ag could be incorporated into solid solution of the ceramics as Ag{sup +}. As a whole, the Curie temperature (Tc) and dielectric constant of the ceramics decreased with Ag addition. However, Ag addition had no obvious effect on the insulation resistivity. The results inferred that Ag{sup +} could substitute for Pb{sup 2+} at A site of ABO{sub 3} lattice, thereby oxygen vacancies were generated.

International Nuclear Information System (INIS)

Turkish English ... Authors Sahin, O. (Suleyman Demirel University, Department of Physics, Isparta (Turkey))

British Library Electronic Table of Contents (United Kingdom)

Objective.The interest of dental research in metal-free restorations has been rising in the last 20 years following the introduction of innovative all-ceramic materials in the daily practice. In particular, high strength ceramics and related CAD/CAM techniques have widely increased the clinical indications of metal-free prostheses, showing more favourable mechanical characteristics compared to the early ceramic materials.The purpose of the present paper is providing a brief review on the all-ceramic dental materials, evaluating pros and cons in the light of the most recent scientific results and of the authors? clinical experience.Materials. A structured review of the literature was given on the basis of medical and engineering papers published in the last decades on the use of dental cera...

International Nuclear Information System (INIS)

A survey is presented of the principles and practice of tailoring sintering liquid composition and processing cycle to enable crystallisation of intergranular phases in silicon nitride and sialon ceramics. Critical features in sialon ceramics are the O/N balance in residual glasses and post-sintering heat-treatment temperatures to enable nucleation of either intermediate phases at constant composition or oxide phases with re-partitioning of non stoichiometric components in #beta#' or #alpha#' solid solutions. Crystallisation of disilicate phases in non-sialon compositions exemplifies a problem in control of polymorphs with differing atomic volumes. Crystallisation of intergranular phases has an influence mainly on high-temperature mechanical and environmental behaviour of these ceramics. (orig.).

Science.gov (United States)

... 1. Reeber, RR, Kusy, RP, Yu, N. and Chu, WK " Formation of a Solid Lubricant in Boron Carbide by Nitrogen Ion Implantation and Laser Annealing ...

Science.gov (United States)

Description of courses, curriculum and degree program. "Ceramic and materials engineers design, develop, and participate in the manufacture of both standard and new materials intended for use in a wide variety of industries with diverse applications. These range from the semi-conductor to the aerospace and finally to the traditional ceramics industry. The broad scope of industrial responsibilities handled by ceramic and materials engineers requires knowledge in mathematics, science, engineering, and the social sciences, skills in problem solving, engineering analysis, design, and written and oral communication. The baccalaureate program integrates laboratory with classroom experiences to prepare students for life-long learning. Courses covering thermodynamics, kinetics, mechanical behavior, processing and characterization of materials prepare students for careers in industry and/or for graduate school. Clemson University ...

Energy Technology Data Exchange (ETDEWEB)

Interest in finding out passive ways to keep the variation in the indoor climate within the comfort zone is gaining in popularity. One possible solution is the use of the moisture-buffering property of materials. In this study, the effects of the ventilation system and moisture-buffering properties of the building fabric on the stability of the indoor temperature and humidity are analysed by means of long-term field measurements. Indoor climate measurements were carried out in 170 detached houses (248 rooms). Temperature and relative humidity were measured continuously in bedrooms and living rooms at one-hour intervals over a one-year period. In general, it may be concluded that in this study, the ventilation had a greater effect on the indoor climate than the properties of the building fabric. The dampening effect of hygroscopic materials was remarkably less in the field measurements than it was in simulations in different studies. This indicates that completely non-hygroscopic and ...

Energy Technology Data Exchange (ETDEWEB)

The diffusion of alkali vapours in the anode compartment of a DIR-MCFC produces the deactivation of the internal reforming catalyst. Sets of ceramic porous membranes purposed to limit the diffusion have been manufactured by different techniques and the influence of the preparation technique and of the preparative variables on the morphological characteristics of the membranes structures has been studied.

Energy Technology Data Exchange (ETDEWEB)

The peculiarities of pulsed laser melting and evaporation of the superconducting ceramics are analyzed by means of numerical simulation. The appearance of the overheated metastable states in solid and liquid phases is shown as a result of the phase front dynamics and volume nature of laser energy release. A method of dynamic adaptation for the multifront Stefan problem is proposed.

Energy Technology Data Exchange (ETDEWEB)

According to the present invention, a joined product is at least two ceramic parts, specifically bi-element carbide parts with a bond joint therebetween, wherein the bond joint has a metal silicon phase. The bi-element carbide refers to compounds of MC, M.sub.2 C, M.sub.4 C and combinations thereof, where M is a first element and C is carbon. The metal silicon phase may be a metal silicon carbide ternary phase, or a metal silicide.

Science.gov (United States)

A new dual focal point electro-optic lens that is switchable to focusing and unfocusing is proposed and successfully demonstrated. This electro-optic lens is constructed by coating transparent fine electrodes in the Fresnel-zone plate onto a PLZT ceramic plate. Its focal length changes from 1.25 m to infinity binary at 515 nm with the external voltage of 210 V. PMID:20725208

Energy Technology Data Exchange (ETDEWEB)

For many industrial applications, materials are desired which combine light weight, high temperature strength, and stability in corrosive environments. Among competing materials, ceramics are noteworthy candidates for such applications. The use of ceramics is often constrained, however, by brittleness; i.e., low toughness. Ceramic composites are being developed to overcome this limitation. With recent advances in ceramic fiber technology, it is possible to design a composite material based on continuous ceramic fibers embedded in a ceramic matrix. The use of ceramic composites in industrial applications will result in reduced fuel consumption, but will also prevent airborne pollution (principally NO, SO{sub x}, CO{sub 2}, and particulates), and economically benefit the end user through energy and environmental savings and increased ...

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There are a number of characteristics exhibited by ceramic materials that may provide potential benefits for the reciprocating internal combustion engine. However, the brittle nature of these materials together with a variability in strength has created difficulties in applying ceramic materials to the engine environment. Although a wide range of physical properties is available from contemporary ceramic materials, a material offering consistently high strength has yet to be developed. For sliding-contact applications, desirable characteristics include good wear resistance, low friction, ability to join metals and good heat dissipation. Test results have shown that cam/follower components with cast iron cam sliding on a silicon nitride follower exhibit very low wear rates. The application of silicon carbide to face seals has also shown substantial reductions in both friction and wear when compared with conventional ...

International Nuclear Information System (INIS)

This study presents the findings of radiometric analysis carried out to determine the activity concentrations of natural radionuclides in raw materials (clay, kaolin, quartz, feldspar, dolomite, alumina, bauxite, zirconium minerals, red mud and frit) and end products (glazed ceramic wall and floor tiles) in the Turkish ceramics industry. Hundred forty-six samples were obtained from various manufacturers and suppliers throughout the country and analyzed using gamma-ray spectrometer with HPGe detectors. Radiological parameters such as radium equivalent activity, activity concentration index and alpha index were calculated to assess the radiological aspects of the use of the ceramic end products as decorative or covering materials in construction sector. Results obtained were examined in the light of the relevant national and international legislation and guidance and compared with the results of similar studies reported in ...

Science.gov (United States)

The kinetics of electrical breakdown of thin (15-70 ?m) layers of polymers and ceramics in a constant-sign field at 77-480 K has been investigated. The temperature dependences of the longevity (breakdown waiting time) of both dielectrics have been found to be similar to each other. At elevated temperatures, the longevity of the dielectrics varies exponentially with increasing temperature, and at reduced temperatures, it is temperature-independent (there is an athermal plateau). The mechanisms of elementary events controlling the process of preparation of the dielectrics for breakdown at elevated and reduced temperatures are the thermal-fluctuation over-barrier electron transition from trap to trap and the tunneling (under-barrier) transition, respectively. The hopping electron transport in the field direction gives rise to critical space charges causing breakdown of the dielectrics. The transition barrier heights (trap depths) have been determined. The ...

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... efforts in developing and testing prototype materials or tools and Full Development Projects to ...

Science.gov (United States)

Near-infrared spectroscopy is a convenient tool for measuring nanotube / carbonaceous impurities

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The advent of sophisticated automation equipment and computer hardware and software is changing the way manufacturing is carried out. To compete in the global marketplace, manufacturing companies must integrate these new technologies into their factories. In addition, they must integrate the planning, control, and data management methodologies needed to make effective use of these technologies. This paper provides an overview of recent approaches to achieving this enterprise integration. It then describes, using simulation as a particular example, a new tool`s perspective of enterprise integration.

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The purpose of this paper is to inform commercial building designers about an energy analysis tool which can aid them in making appropriate decisions about daylighting. The energy nomographs are an energy design tool which calculate the annual energy consumption of commercial buildings, including lighting, heating, cooling, domestic hot water, fans, pumps, and miscellaneous items. This paper specifically discusses the daylighting aspects of the tool. The calculation procedure is presented with an example to explain how this design tool can be used to make good energy decisions early in the design process.

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In support of the efforts to apply ceramics in advanced heat engines, a study was made of the sliding performance of ceramics at the ring/cylinder interface of low heat rejection engines. The objective was to understand the basic mechanisms controlling the wear of candidate ceramics and thereby identify means for applying these ceramics effectively. Attempts to operate three different zirconias, silicon carbide, silicon nitride, and several plasma-sprayed ceramic coatings without lubrication were unsuccessful because of high friction and high wear rates. Experiments using a polyalphaolefin lubricant at temperatures to 260 C identified several combinations having wear rates in the general range likely to be acceptable for engines. Plasma-sprayed coatings of chromium oxide and hypersonic powder flame sprayed coatings of cobalt-bonded tungsten carbide performed particularly well as ...

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The purpose of this investigation was to simulate a machining front from an abrasive waterjet and its movements in a ceramic material. Wear factors affecting the abrasive waterjet nozzle were also to be established. Therefore, a low inclination angle (9[degree]) was used between the nozzle and test sample, simulating a moving machine front. A standard nozzle with an inner diameter of 0.76 mm was used in the test, and it was placed close to the samples. The outer diameter of the abrasive nozzle was 9.5 mm. The high wear rate from abrasive waterjets makes it possible to machine hard ceramics-including dense alumina, titanium boride, silicon nitride, and composites-at high machining speeds.

British Library Electronic Table of Contents (United Kingdom)

The design of solid breeder blankets is strongly affected by the low values of thermal conductivity and density of ceramic breeder pebble beds. A significant rise of both quantities would enhance the thermal performance and lead to an increased tritium breeding ratio. In order to improve these quantities pretreated lithium orthosilicate pebble material was dry pressed and subsequently sintered. The thermal conductivity of cylindrical pellets was determined by the heat pulse method using a laser flash device. A pebble bed characteristic sample was also investigated in order to check the measurement accuracy in comparison with previous results. Furthermore, two samples of low density cellular ceramics were also prepared by infiltration of polymer foams with a ceramic slurry. The thermal cond...

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The tribological behavior of SiSiC/100Cr6-, Si/sub 3/N/sub 4//100Cr6- und Al/sub 2/O/sub 3//100Cr6-pairs has been investigated with oscillating load on a spherical disc/disc tribometer. The prevailing wear mechanism of the Si ceramics is tribooxidation, which leads to the formation of a SiO/sub 2/ protective layer with a reduction in friction and wear. With frequencies >1 kHz, this effect increases, resulting in low friction coefficients and wear rates. The prevailing mechanism of the oxid ceramic is surface fatigue. The hard wear particles produce severe abrasive wear. This effect is intensified with higher frequencies.

International Nuclear Information System (INIS)

The small pilot facility of a cyclone type suspension incineration system of radioactive waste was set up in order to evaluate the decontamination efficiency of a high efficiency ceramic filter. The evaluation was made by use of "5"4Mn, "5"9Fe, "6"0Co, "6"5Zn and "1"3"7Cs. 1. The decontamination factor by one line of ceramic filter for every species were over 10"5. 2. The decontamination factor increased by one oder when water vapor exists in off-gas. The same tendency was also observed when iron dioxide existed at the incineration of cation exchange resin. (author).

International Nuclear Information System (INIS)

The use of Sialon ceramics has been restricted by the high temperature required for synthesis and the expense of the pure oxide and nitride raw materials required. For refractory applications the purity required is less demanding and it has been possible to exploit the outstanding durability of the Sialons at moderate cost. New low cost manufacturing routes are being developed by nitriding silicon metal powder at relatively low temperature with clay and various additives depending on the Sialon required. For example the introduction of carbon or fine silicon carbide allows the preparation of beta Sialons and alpha Sialons which can be stabilised by including the appropriate cations. A wide range of composite Sialon bodies with diverse properties can be prepared by a one step process. Current projects developing the synthesis routes are aimed, in the first instance, at refractory manufacture but are showing promise for more sophisticated applications. Copyright ...

British Library Electronic Table of Contents (United Kingdom)

Objectives: The aim of this study was to evaluate the in vitro behaviour of all-ceramic zirconia molar crowns in regard to different core designs and marginal fit. Methods: Identically shaped methacrylate molars were prepared according to the ceramic restoration directives resulting in a 1-mm deep circular shoulder preparation. They were embedded in polymethylmethacrylate resin after covering their roots with a polyether layer to simulate periodontal mobility. The crown cores were made of yttria-stabilized zirconia veneered with a corresponding veneering ceramic. The crowns were divided into 5 groups (n=8) which differed in core design and cement gap thickness: #1: simple core, 40mm cement; #2: core with minimal occlusal support, 40mm cement; #3: core with optimized cusp support, 40mm ceme...

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Sintered glass-ceramics have been produced using municipal incinerator solid residues and glass cullet or an inert waste, from feldspars processing, as sintering aids. The capability of three different mixtures, either previously vitrified or not, to be sintered was investigated by means of linear shrinkage, water absorption and bulk density measurements, and by X-ray diffraction analysis and scanning electron microscopy observations. Particular attention has been addressed to the study of particle size effect on the sintering process. The conclusions that can be drawn from the experimental study are that the preliminary vitrification step is essential in order to obtain a dense sintered glass-ceramic product in the 850-1050 C temperature range developing silicate crystalline phases. The optimal powder particle size that confers a good densification degree was found to be < 45 {mu}m. (orig.)

International Nuclear Information System (INIS)

BaTi_0_._9(Ni_1_/_2W_1_/_2)_0_._1O_3 ceramics were fabricated and their dielectric properties were investigated. With the sintering temperature increasing from 1250 to 1280 deg. C, the grain size abruptly increases from 1-2 to 20-40 #mu#m, accompanying significant changes in dielectric response. The samples with larger grains exhibit giant dielectric constant characteristics, which are considered to be mainly attributed to the domain boundary effect. The activation energies of the dielectric relaxation E_r_e_l_a_x=0.325 eV reveal the existence of microdomains in larger grains. The ac conductivity results also give the evidence of the domain boundary effect in the present ceramics.

British Library Electronic Table of Contents (United Kingdom)

Statement of problem Even though metal ceramic restorations (MCRs) are widely used by clinicians, the influence of the metal on the color of overlaying porcelain is unknown. Purpose The purpose of this study was to analyze the color alterations of different types of metal ceramic alloys during several stages of metal surface preparation and to determine the effect of those changes on the resulting color of opaque porcelain (OP). Material and Methods Seven different types of alloys (3 base metal, 3 noble, and 1 high noble) were used to prepare disk-shaped specimens (1 mm x 10 mm, n=3), followed by OP application (0.1 mm). Lab values of specimens were recorded after different stages of metal surface preparation (ingot, after casting, after oxidation, and after the OP application) in addition...

International Nuclear Information System (INIS)

Different semi precious alloys (Pd-Ag, Pd-Au) have been studied after thermal oxidation treatments to analyze the mechanical improvement of the interface between the metal and the ceramic. Using the four point bending test, the authors have analyzed the different steps corresponding to the mechanical evolution of the bi-material : cracking energy on the surface, relaxation energy after first cracking, propagation energy of cracks at the interface zone. It has been shown that some alloys only have a high resistance to the interface cracking and the role played by the interface reactions to improve this property. (orig.).

Science.gov (United States)

was to mount Pd-Ag terminated MLCCs onto gold plated mounting pads of a ... to protect against incorrect shipment of pure tin-plated MLCCs when Pd-Ag ...

Energy Technology Data Exchange (ETDEWEB)

Progress is reported in the following areas: metallurgy and ceramics (structure of materials, mechanical properties, physical properties), experimental research, and particle-solid interactions (irradiation effects on alloys). (DLC)

Energy Technology Data Exchange (ETDEWEB)

Sandia National Laboratories is currently involved in the optimization of a Plane Shock Generator Explosive Lens (PSGEL). The PSGEL component consists of a detonator, explosive, brass cone and tamper housing. The purpose of the PSGEL component is to transmit a plane shock wave through the 4340 steel bulkhead (wave separator) which has a ferro-electric (PZT)ceramic disk attached to the opposite surface of the steel bulkhead. The planar shock wave depolarizes the PZT 65/35 ferro-electric ceramic to produce an electrical output. One aspect of the optimization program involves the possible replacement of 4340 steel with PH13-8Mo steel for the bulkhead. These materials, as well as the PZT 65/35 ferro-electric ceramic and the brass for the cone, required the stock characterization with respect to Hugoniot parameters. The work presented here gives the shock Hugoniot values for these four materials and documents their measurements.

International Nuclear Information System (INIS)

A powder mixture of #alpha#-Si_3N_4, Al_2O_3, and TiO_2 was hot-pressed using different sintering cycles to search for an optimum in situ formed #beta#-O-sialon-TiN composite. The impulse excitation technique (IET), high-temperature X-ray diffraction (HTXRD), and scanning electron microscopy (SEM) were used to investigate the microstructure. Below the temperature of 1300 deg. C, the high-temperature internal friction (Q "-"1) decreases with the increase of sintering temperature, whereas the density of the material increases with the increase of sintering temperature. At a sintering temperature higher than 1850 deg. C, the ceramic could not be densified and O-sialon was not formed. Also, the mechanical properties of ceramics hot-pressed using different sintering cycles were assessed. The ceramic hot-pressed at 1700 deg. C for 10 min displays a combination of high hardness and good fracture toughness, due to an optimum ...

Science.gov (United States)

... Structures 9623595 P EPSCOR ENG DMI MATERIALS PROCESSING & MANUFCT Textile Engineering Department AL ... MPS DMR METALS, CERAMICS AND ELECT MATRS Materials and Mechanical Engineering AL Auburn University ...

Energy Technology Data Exchange (ETDEWEB)

In the second part of this paper the author concludes his examination of the application of thermoplastic materials and also considers alumina ceramics, cast basalt and glass, rubbers, resins and wear-resistant steels

International Nuclear Information System (INIS)

This work has been undertaken with a view to study the effect of lanthanum content on properties of PLZT ceramics. The polycrystalline complex compounds of PLZT with Pb_1_-_xLa_x(Zr_0_._4_0Ti_0_._6_0)_1_-_x_/_4O_3, +10% PbO formula were prepared from the nano-size individual oxides powders by hot-pressed process. Transparent PLZT (x/40/60) bulk ceramics with pure tetragonal phase was obtained. The studies of the microstructures, dielectric and ferroelectric properties of the ceramics were carried out. The experiment results showed that when La content increased from 7 to 13 mol.%, the grain size increased from 2 to 7 #mu#m. La content also effects the dielectric property obviously, the dielectric constant increased with La content increasing. Moreover, the ferroelectric properties are sensitive to the variation of La content.

Energy Technology Data Exchange (ETDEWEB)

The chemical interaction of a Si{sub 3}N{sub 4} ceramic with pristine and oxidised 100Cr6 steel was studied by means of static interaction couple experiments between 500 and 1200 C. Si{sub 3}N{sub 4} was not chemically stable in contact with oxidised steel at elevated temperatures, and reacts with the formation of N{sub 2}, SiO{sub 2} and/or Fe{sub 2}SiO{sub 4} at temperatures at and above 1000 C. At 700 and 500 C, Si diffusion into the oxide layer indicated the dissociation of the Si{sub 3}N{sub 4} ceramic. Si{sub 3}N{sub 4} also dissociated in contact with pristine steel. In the temperature region between 700 and 1100 C, the Si dissolves and diffuses into the steel whereas a nitrogen pressure is built-up in the voids of the metal-ceramic interface, limiting the degree of interaction. Above 1100 C, the nitrogen dissolves and diffuses into the steel as well, enhancing the reactivity and resulting in the formation of a ...

Energy Technology Data Exchange (ETDEWEB)

This patent describes a method comprising applying a passivation layer of CaF{sub 2} to the surface of a superconductive ceramic oxide by evaporation. The CaF{sub 2} layer is effective to passivate the oxide surface without disrupting the superconductive properties.

Energy Technology Data Exchange (ETDEWEB)

This report covers the test methods and equipment for testing aircraft armor both hard and soft. The hard armor are the typical ceramic type while the soft armor are various types of layered composite materials. 10 figs. (JEF)

International Nuclear Information System (INIS)

Sialons are phases in the Si-Al-O-N and M-Si-Al-O-N systems where M includes Li, Mg, Ca, Sc, Y and the rare earth elements. They are comparable in variety with the mineral silicates and are built up of one-, two-, and three-dimensional arrangements of (Si,Al)(O,N)/sub 4/ tetrahedra in the same way that the structural units of the silicates are SiO/sub 4/ tetrahedra. These new materials include N-containing ceramics, glasses and glass-ceramics that are being explored for their thermal, chemical and physical properties.

British Library Electronic Table of Contents (United Kingdom)

Abstract Silicates are one of the most important classes of compounds on this planet, and more than 1000 silicates have been identified in the mineral kingdom. Additionally, several hundreds of artificial silicates have been synthesized. The substitution of oxygen by nitrogen leads to the structurally diverse and manifold class of nitridosilicates. Silicon nitride, one of the most important non-oxidic ceramic materials, is the binary parent compound of nitridosilicates, and it symbolizes the inherent material properties of these refractory compounds. However, prior to the last decades, a broad systematic investigation of nitridosilicates had not been accomplished. In the meantime, these and related compounds have reached a remarkable level of industrial application. This review illustrates...

Energy Technology Data Exchange (ETDEWEB)

A method of assembling two or more parts together that may be metal, ceramic, metal and ceramic parts, or parts that have different CTE. Individual parts are formed and sintered from particles that leave a network of interconnecting porosity in each sintered part. The separate parts are assembled together and then a fill material is infiltrated into the assembled, sintered parts using a method such as capillary action, gravity, and/or pressure. The assembly is then cured to yield a bonded and fully or near-fully dense part that has the desired physical and mechanical properties for the part's intended purpose. Structural strength may be added to the parts by the inclusion of fibrous materials.

Science.gov (United States)

In this study, different proportions of silver-palladium alloy used as an inner electrode are adopted to fabricate (Zn,Mg)TiO3-based multilayer ceramic capacitors. Effects of sintering temperature, and measuring frequency on the dielectric properties of the samples with different proportions of the Pd-Ag inner electrode are investigated. The continuity of the inner electrode and the proportion of Pd-Ag of the inner electrode of samples sintered at different temperatures play important roles in determining the dielectric properties.

Energy Technology Data Exchange (ETDEWEB)

The objective of this contract is to research, develop and demonstrate a novel ceramic membrane reactor system for the low-cost conversion of natural gas to synthesis gas and hydrogen for liquid transportation fuels: the ITM Syngas process. Through an eight-year, three-phase program, the technology will be developed and scaled up to obtain the technical, engineering, operating and economic data necessary for the final step to full commercialization of the Gas-to-Liquids (GTL) conversion technology. This report is a summary of activities through September 1999.

UK PubMed Central (United Kingdom)

BackgroundThe use of measurement tools is an essential part of good evidence-based practice; however, physiotherapists (PTs) are not always confident when selecting, administering,...Full Text Available

UK PubMed Central (United Kingdom)

DNA transposons are efficient tools in transgenesis and have therefore become popular in the analysis of the regulatory genome in vertebrates via enhancer trap screens. Here, I discuss recent progress...Full Text Available

UK PubMed Central (United Kingdom)

In 2008, a clinical information tool was developed and embedded in the electronic health record system of an academic medical center. In 2009, the initial information tool, Clinical-e, was superseded...Full Text Available

UK PubMed Central (United Kingdom)

Adopting the approach taken with New Caledonian crows (Corvus moneduloides), we present evidence of design complexity in one of the termite-fishing tools of chimpanzees (Pan...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The purpose of this memo is to give an update on our work on ceramic laser materials--feasibility proposal 04-FS-006. Transparent ceramic materials have several major advantages over single crystals in laser applications including, ease and robustness of manufacturing, large apertures, design flexibility, fracture toughness, high activator concentrations, uniformity of composition, no residual stress, and others discussed in the proposal. After a decade of working on making transparent YAG:Nd in 1995 Japanese workers demonstrated samples for the first time that performed as well in lasers as their single crystal counterparts. Since then several laser materials have been made and evaluated. For these reasons, developing ceramic laser materials is the most exciting and futuristic materials topic in today's major solid-state laser conferences. The highlights and executive summary of our work to date are: (1) Ordered a ...

Energy Technology Data Exchange (ETDEWEB)

The Externally-Fired Combined Cycle (EFCC) offers a method for operating high-efficiency gas and steam turbine combined cycles on coal. In the EFCC, an air heater replaces the gas turbine combustor so that the turbine can be indirectly fired. Ceramic materials are required for the heat exchange surfaces to accommodate the operating temperatures of modern gas turbines. The ceramic air heater or heat exchanger is the focus of this program, and the two primary objectives are (1) to demonstrate that a ceramic air heater can be reliably pressurized to a level of 225 psia (1.5 MPa); and (2) to show that the air heater can withstand exposure to the products of coal combustion at elevated temperatures. By replacing the gas turbine combustor with a ceramic air heater, the cycle can use coal or other ash-bearing fuels. Numerous programs have attempted to fuel high efficiency gas turbines directly with coal, often ...

Science.gov (United States)

We present jFuzz, a automatic testing tool for Java programs. jFuzz is a concolic whitebox fuzzer,

Science.gov (United States)

Abstract: HARVEST was designed as a strategic research and planning tool, allowing assessment of the spatial pattern consequences of broad timber management ...

Science.gov (United States)

... Dynamics) environment (ref. 13) to work seamlessly with their flagship products, MSC.Nastran and MSC.Patran. In addition ...

Science.gov (United States)

Many cost estimating tools use weight as a major parameter in projecting the cost. This is often

Science.gov (United States)

... ire examples of successive operations, as are the breakout operations GOODWOOD and COBRA. Also, for the first time, ...

British Library Electronic Table of Contents (United Kingdom)

China's propaganda machine seeks to control public opinion at all costs?-?and the media is its tool, writes David Bandurski

Science.gov (United States)

The progress in the development of a surface analysis tool based on the excitation of characteristic

Energy Technology Data Exchange (ETDEWEB)

The fabrication of a Prototype 275/sup 0/C Geothermal Temperature Tool is reviewed. This tool fabrication uses hybrid circuits that were developed at Sandia National Laboratories and are now being built at Teledyne Philbrick. To achieve high-temperature operation, the standard military specification hybrid technology was modified in fabrication processes and materials.

UK PubMed Central (United Kingdom)

TRF-CUT, an ARB-implemented tool, was developed to predict in silico the terminal restriction fragments of aligned small-subunit rRNA gene or functional gene sequences. Application of this new tool...Full Text Available

CERN Document Server

Modern HENP experiments such as CMS and Atlas involve as many as 2000 collaborators around the world. Collaborations this large will be unable to meet often enough to support working closely together. Many of the tools currently available for collaboration focus on heavy-weight applications such as videoconferencing tools. While these are important, there is a more basic need for tools that support connecting physicists to work together on an ad hoc or continuous basis. Tools that support the day-to-day connectivity and underlying needs of a group of collaborators are important for providing light-weight, non-intrusive, and flexible ways to work collaboratively. Some example tools include messaging, file-sharing, and shared plot viewers. An important component of the environment is a scalable underlying communication framework. In this paper we will describe our current progress on ...

Energy Technology Data Exchange (ETDEWEB)

A new German-engineered articulated drilling tool that can take the vertical to the horizontal, using about eight metres of curve, was described. The Articulate Downhole Motor has the capability to run radii as long as 57 metres (the usual requirement is 15 metres), under full control. Its ability to rotate and slide while maintaining control is one of the major positives of the technology. The technology also includes a `positive` communication system in its steering tool. The deployment of the positive pulse retrievable measurement-while-drilling (MWD) system brings real-time tool face orientation and hole direction to the surface. In using the tool, formation composition is not an issue; it is designed to withstand any environment.

Energy Technology Data Exchange (ETDEWEB)

A review of current daylighting design tools indicates that over 30 tools are now available, including nomographs, protractors, overlays, and programs for micro-, mini-, and mainframe computers. Computer-based tools allow testing and analyzing of more design alternatives under a wider variety of conditions than was previously practical with slower techniques, but they have not fundamentally changed the information available to the design professional. These tools are applicable to certain limited functions of the design process and do not address the varying information needs of the designer at various points in the design process. We describe a concept for a computer-based building envelope design tool that is structured to overcome many of the limitations of the existing tools. The tool would address daylighting design in the context of ...

International Nuclear Information System (INIS)

Lithium Ceramics offer tremendous potential as a source for the production of tritium ("3H) for fusion power reactors. Their successful application will depend to a great extent upon the diffusion properties of the "6Li within the matrix. Consequently knowledge of "6Li concentration gradients in the ceramic matrices is an important requirement in the continued development of the technology. In this investigation, the neutron depth profile (NDP) technique has been applied to the study of concentration profiles of "6Li in lithium aluminate ceramics, doped with 1.8%, 50% and 95% "6Li isotopic concentrations. Specimen for analysis were prepared at Battelle (PNL) as pellet discs. Samples for diffusion studies were arranged as diffusion couples in the following manner: 1.8% "6Li discs/85% "6Li powder. Experiments were performed at the Texas A and M Nuclear Science Center Reactor Building, utilizing 1 MW equivalent thermal neutron ...

International Nuclear Information System (INIS)

A radioactive Waste Incineration System (WIS) with suspension combustion is noticed as effective volume reduction technology of low level radiactive wastes that are increasing every year. In order to demonstrate the decontamination efficiency of ceramic filter used on WIS, this test has been carried out with the test facilities as joint research of Central Research Institute of Electric Power Industry (CRIEPI) and Sumitomo Heavy Industries, Ltd. Miscellaneous combustible waste and power resin, to which 5 nuclides (Mn-54, Fe-59, Co-60, Zn-65, Cs-137) were added, were used as samples for incineration. As the result of the test, it was verified that Decontamination Factor (DF) of the single stage ceramic filter was usually kept over 10"5 for every nuclide, and from the results of above DF, over 10"8 is expected for real commercial plant as a total system. Therefore, it is realized that the off-gas clean up system of the WIS composed of only single ...

Energy Technology Data Exchange (ETDEWEB)

The dispersion of more than 20 vol pct submicrometer ceramic particles within a metallic matrix and the deposition of such a cermet to form a thick and tough coating presents problems. Most of the coating techniques have failed in attempting to homogeneously disperse very fine and hard particles in large amounts while avoiding their decomposition or reaction with the metal matrix during the deposition process. A simple and efficient method has been developed for producing ceramic-containing composite coatings. It consists in synthesizing cermet-based materials and in depositing them by a rapid solidification process, such as thermal spraying. Boride- and carbide-based materials have been successfully obtained by plasma spraying reactive powders comprising the basic reagents. These materials, with a microstructure of submicrometer ceramic particles dispersed in a metallic matrix, exhibit good wear-resistant properties ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Purpose: Long-term success of metal ceramic restorations depends on metal ceramic bond strength. The purpose of this study was to determine whether recasting of base-metal alloys has any effect on metal ceramic bond strength. Materials and Methods: Super Cast and Verabond base-metal alloys were used to cast 260 wax patterns. The alloy specimens were equally divided into five groups and cast as: group A 0.0%, B 25%, C 50%, D 75%, and E 100% once-cast alloy. Each group was divided into two subgroups: the first group was cast with Super Cast and the second with Verabond. In each subgroup half of the cast alloys were veneered with Vita VMK 68 and the others with Ceramco 3. Results: Recasting decreased bond strength (p < 0.006) when used for 50% once-cast alloy. Group E with 100% new S...

International Nuclear Information System (INIS)

Fine ceramic particles of zirconia toughened alumina (ZTA), titania toughened alumina (TTA), and zirconia-titania toughened alumina (ZTTA) have been synthesized by ultrasonic spray pyrolysis (USP) at various temperatures from starting salt solutions of various compositions aiming for the development of catalytic material. These particles were characterized for properties such as shape, size and size distribution, diffraction pattern, and chemical and phase composition of elements by scanning electron microscopy (SEM), particle size analyzer (PSA), x-ray diffraction (XRD), and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Chemical compositions and sizes of ceramic composites have been controlled by the stoichiometry of salt solutions and the flow rate of spraying solutions. The optimum experimental conditions for the various composite particle synthesis have been proposed.

Energy Technology Data Exchange (ETDEWEB)

This paper describes potentials on fuel economy and NO{sub x} exhaust emissions of a series hybrid urban bus system equipped with a ceramic gas turbine engine (CGT). The simulating program developed in-house was used to analyze influences of several parameters of each main components of the hybrid vehicle system on the performance of the bus running on the modified bus driving cycle. The basic data used in this analysis for a CGT was derived from the results of 'the Automotive 100kW CGT Project' of Japan. A dynamic response of a CGT-Generator rotating system was very much improved by introducing of 'Assisting system' in which the generator was used as an acceleration-deceleration assisting device when much acceleration or deceleration was needed. This system would make a CGT operate along the optimum operating line (fuel minimum line) even under the unsteady driving conditions. This analysis showed that the fuel economy of an ...

International Nuclear Information System (INIS)

The densification of #alpha#"1-and #alpha#"+#beta#"1-sialon ceramics has been studied by means of in situ dilatometry. It is seen that the densification is greatly affected by the reaction sequences and the grain growth. The formation and densification of sialons start simultaneously as the dissolution of nitrides into the oxide eutectic liquid phase occurs. The formation of sialons is complete at 1800 deg C., while full densification can only be obtained by using gas pressure sintering. The typical microstructure of both #alpha#"'-and mixed #alpha#'+#beta#'-sialon ceramics consists of a crystalline phase of sialons and a small fraction of amorphous phase at grain boundaries. Vickers hardness (HV0.5) was measured by using the indentation technique, and the biaxial bending strength (#sigma#_b_i) was determined with the 'ball-on-ring' test. Fracture toughness was determined by using both the indentation and single-edged notched beam techniques. ...

Science.gov (United States)

The progress made during the first two years of a program to study the migration of grain boundaries in ceramic oxides is reported. The principal results of the program are concerned with the structure of grain boundaries in ..cap alpha..-Al/sub 2/O/sub 3/, although important new information has also been obtained on grain boundaries in spinels and both germanlum and silicon. Attention is focused on the basal twin boundary in ..cap alpha..-Al/sub 2/O/sub 3/ which had been identified as a model interface in early work. A series of new grain boundaries exemplified by the (11anti23) twin are also discussed briefly as is the rhombohedral twin interface. Earlier results on the first-order (..sigma..=3) twin in spinel have been extended with the development of models for the computer-simulation of high-resolution TEM images of these interfaces. A study of low-angle grain boundaries in spinel is giving new insight into the effect which the large size of the unit cell and ...

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Glass-ceramic materials containing 0-60% glass, 0-40% cordierite and 0-40% mullite were developed with dielectric constant lower than of Al{sub 2}O{sub 3} (5.2-6.7). The following glasses were used: SiO{sub 2}, CaO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}-SiO{sub 2}, CaO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}, CaO-ZnO-B{sub 2}O{sub 3}, CaO-ZnO-Al{sub 2}O{sub 3}B{sub 2}O{sub 3}, BaO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}-SiO{sub 2} and BaO-ZnO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}-SiO{sub 2}. The influence of the content of the particular components on the value of dielectric constant of the ceramics was investigated. (author). 9 refs, 3 tabs.

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An experimental investigation of premixed methane-air combustion within the one-dimensional porous ceramic burners for various burner configurations is presented. The burner is nonhomogeneous because of different pore size ceramic block used in different section of the burner. Therefore, the thermophysical and transport properties are nonuniform along the burner core length. The burners are constructed of partially stabilized zirconia. The CO and NO{sub x} emissions, flame speed, and flame stability are examined and compared at lean equivalence ratios for five different burner configurations. The sandwich-structured burner has very favorable flame stabilizing characteristic due to the radiation reflecting region. While the combustion proceeds at faster rate than other burner configurations, the radiation reflecting region and the exit surface have low temperature. Thus the NO{sub x} emission can be kept at the same low level as the other burner ...

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The effects of Fe and B{sub 4}C on the sintering behavior and mechanical properties of TiB{sub 2} ceramics have been studied. Sintering was performed in an Ar atmosphere at 2000{degrees}C using attrition-milled TiB{sub 2} powder. When a small amount of Fe (0.5 wt%) was added, abnormal grain growth occurred and the sintered density was low. In the case of B{sub 4}C added along with 0.5 wt% Fe, however, abnormal grain growth was remarkably suppressed, and the sintered density was increased up to 95% of theoretical. But with excess Fe addition (5 wt%), B{sub 4}C grains did not act as a grain growth inhibitor, and B{sub 4}C grains were frequently trapped in large TiB{sub 2} grains. The best mechanical properties were obtained for the TiB{sub 2}-10 wt% B{sub 4}C-0.5 wt% Fe ceramics, which exhibited a three-point bending strength of 400 MPa and a fracture toughness of 5.5 MPa {center dot} m{sup 1/2}.

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The Energy Nomographs are a quick, simple-to-use tool for designing energy conscious lighting systems. Many assumptions and simplifications have been incorporated in the tool which may decrease its accuracy. However, the tool is accurate enough for use in Schematic Design, where design decisions have the largest impact on end energy use. It is not intended to replace all other energy design tools but rather supplement them when quicker decisions must be made. An important aspect of this analysis technique is its graphic procedural quality. As each design decision is made in the course of completing the nomograph procedure, the effects of each may be seen graphically and alternatives chosen without having to complete the entire process. This will have time but, more important, will act as an educational tool to the designer. As more calculations are completed, the user realizes how ...

British Library Electronic Table of Contents (United Kingdom)

A testing methodology, which includes the evaluation of free sintering strain, stress-induced dimensional changes, and weight changes, was developed to determine the critical dimensional changes and thermomechanical response during presintering (i.e., before densification). The effects of organic binder burnout, decomposition of phases, and phase changes on the thermomechanical behavior of a ceramic green body, consisting of methylcellulose as a binder, gibbsite, silica, and alumina, were studied. The compressive stress-strain behavior was found to be nonlinear. The average compressive and tensile strengths of the sample at room temperature were -14.5 and 1.06 MPa, respectively. Both the compressive and tensile strengths decrease by two orders of magnitude with the increasing temperature a...

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Creation of new multi-composite materials is an essential issue to attain an innovative improvement of the current nuclear technology. In this paper, some highlights are focused on the research of creation of those materials and the relating subjects in NIRIM. (1) The KOH corrosion test method are expected to be efficiently available in the limited cases instead of Na corrosion test one. (2) The preliminary creation of the multi-composite ceramics were achieved by Y- ion implantation into sapphire and the RF sputtering, of which the specified orientation was realized by the existence of the buffer layer. The importance of the defect control are described with the relation to the corrosion resistance improvement. (3) The ion beam induced phenomena have been investigated on the surface change of silica glass and the crystallization of Cu film on SrTiO{sub 3}. (4) The electronic states of the alkali-metal adsorbed surfaces and that of the collision ion have been ...

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Future power plants will be more fuel efficient, environmentally benign, and economical than current power plants. A high performance power system (HIPPS), based on a coal-fired combined cycle, is currently being developed. The corrosion and temperature-strength properties of currently available metallic materials limit the maximum efficiency of this cycle. Recently, ceramic matrix composites have shown promise in overcoming the design limitations on the future power plants. In particular, the high-temperature, and corrosion and erosion resistant properties of continuous fiber ceramic composites (CFCCs) will allow engineers to design high-temperature heat exchangers, cyclone vortex finder tubes, and other components. Research being performed to evaluate candidate materials for use in future power plants is discussed.

International Nuclear Information System (INIS)

We reported in previous papers that both the near-uv and the visible photosensitivities of ferroelectric-phase PLZT (lead lanthanum zirconate titanate) ceramics are increased by as much as four orders of magnitude by ion implantation or a combination of thermal diffusion of Al and ion implantation. New results are presented here on high-energy (1 MeV) implants of Al and Ni and coimplants of Al + Ne and Ni + Ne, and these results are compared with earlier 500 keV implants of Al and Cr and coimplants of Al + Ne and Cr + Ne as surface modification techniques for increasing the visible photosensitivity of PLZT. The important role of grain size in determining optimum contrast and resolution of stored optical information is described in terms of new experimental results.

International Nuclear Information System (INIS)

The electronic structure and optical properties in tetragonal ceramics PbTiO_3, are studied by using full-potential linearized augmented plane wave method in density functional theory with the generalized gradient approximation by WIEN2K package. The theoretical calculated optical properties and energy loss spectrum yield a static refractive index of 2.59 and a plasmon energy of 22.7eV for the tetragonal phase. The effective electron number at low energy saturates near 22-23eV with the value of 50 for the effective electron number. The results show a indirect band gap of 2.2eV at the I' point in the Brillouin zone. The :calculated band structure and density of states of PbTiO_3 agree with previous experimental and theoretical results.

British Library Electronic Table of Contents (United Kingdom)

Statement of problem Because noble dental casting alloys for metal ceramic restorations have a wide range of mechanical properties, knowledge of these properties is needed for rational alloy selection in different clinical situations where cast metal restorations are indicated. Purpose The purpose of this study was to compare the mechanical properties and examine both the fracture and polished surfaces of 6 noble casting alloys that span many currently marketed systems. Five alloys were designed for metal ceramic restorations, and a sixth Type GPT has Type IV alloy for fixed prosthodontics (Maxigold KF) was included for comparison. Material and methods Specimens (n=6) meeting dimensional requirements for ISO Standards 9693 and 8891 were loaded to failure in tension using a universal testin...

British Library Electronic Table of Contents (United Kingdom)

Statement of problem Titanium is the most biocompatible metal used for dental casting; however, there is concern about its marginal accuracy after porcelain application since this aspect has direct influence on marginal fit. Purpose The purpose of this study was to determine the effect that metal selection and the porcelain firing procedure have on the marginal accuracy of metal ceramic prostheses. Material and methods Cast CP Ti, milled CP Ti, cast Ti-6Al-7Nb, and cast Ni-Cr copings (n=5) were fired with compatible porcelains (Triceram for titanium-based metals and VITA VMK 95 for Ni-Cr alloy). The Ni-Cr alloy fired with its porcelain served as the control. Photographs of metal copings placed on a master die were made. Marginal discrepancy was determined on the photographs using an image ...

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A pillbox RF output window was developed for the L-band pulsed klystron for the Japanese Hadron Project (JHP) 1-GeV proton linac. The window was designed to withstand a peak RF power of 6 MW, where the pulse width is 600 {mu}sec and the repetition rate is 50 Hz. A high power model was fabricated using an alumina ceramic which has a low loss tangent of 2.5x10{sup -5}. A high power test was successfully performed up to a 113 kW RF average power with a 4 MW peak power, a 565 {mu}sec pulse width and a 50 Hz repetition rate. By extrapolating the data of this high power test, the temperature rise of the ceramic is estimated low enough at the full RF power of 6 MW. Thus this RF window is expected to satisfy the specifications of the L-band Klystron. (author).

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The purpose of the present study is to develop a new method for chemical state analysis by means of EPMA(Electron probe microanalyser). The measured X-ray intensity of Si-K{beta} characteristic X-ray spectra were read-out by a 16 bit microcomputer with a RS-232C interface. And using the curve fitting method the quantitative analysis of chemical compositions in a ternary compound that constituted of the same element has been established. The present method was applied to analyse of the friction and wear properties of Si-base ceramics sliding materials. It was found that the wear debris contains both the compositions of the sliding materials and SiO{sub 2}, and the SiO{sub 2} contents in wear debris was changed with relative humidity. The results clearly showed that the proposed method is very useful for determing the compositions in the ternary compound. (author).

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A combination of erosion and corrosion at the Victoria Junction coal preparation plant in Sydney, Nova Scotia was causing serious problems. Schedule 80 mild steel pipes were starting to fail as well as some quarter-inch steel plates in the lauders and chutes. Some corrosion tests were carried out and the high chloride level in the process water was felt to be the single most important contribution to the corrosion problem. Cast basalt was selected as a solution to the pipe wear problem. Three different types of abrasion/corrosion-resistant tiling - basalt tiles, kalceram tiles and ceramic tiles were well suited to the chloride conditions at this plant.

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Hybrid vehicles have two power supplies as engine and electric motor which are used most efficiently corresponding to objects respectively to attain energy-saving and low pollution. In this paper, factors concerning the fuel economy of hybrid vehicles and potential thereof are examined, and the possibility of reducing fuel cost by half is described. As possible modes of highly efficient hybrid vehicles, series hybrid vehicles (SHEV) of conventional internal combustion engine, parallel hybrid vehicles using EV in combination, series-parallel hybrid vehicles (SPHV), series type fuel cell type vehicles, ceramic engine-turbo compound power generating SPHV as well as SHEV, and ceramics gas turbine engine power generating SHEV are mentioned. 10 refs., 14 figs.

International Nuclear Information System (INIS)

The possibility of surface modification of high-speed steel cutting tool by means of vacuum-plasma treatment including ion nitriding in gas plasma followed by the deposition of wear resistant (Ti, Al)N coatings in metal-gas plasma of a vacuum arc discharge is studied. The regularities of nitrided layer formation and the structure of these layers under various operation conditions of cutting tool are investigated. Optimum conditions of vacuum-plasma treatment providing the best wear resistance of cutting are determined

International Nuclear Information System (INIS)

We have used scale models to measure the predicted coupling of electromagnetic fields simulating the effects of high-altitude nuclear electromagnetic pulses (HEMP) on the interior surfaces of electronic components. Predictive tools for exterior coupling are adequate. For interior coupling, however, such tools are in their infancy. Our methodological approach combines analytical, computational, and laboratory techniques in a complementary way to take advantage of their separate strengths. Computer models are a promising tool, as they can be used to treat complex objects with arbitrary shapes, dielectrics, and cables, and multiple apertures. Laboratory tests can expand the domain of investigation even further.

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Systems MEMS sensors C11-20 Lifetime Distributions of Aluminum Electrolytic Capacitors C11-22 Adhesion Strength of Advanced Polymer Films for Flexible and Rigid...

UK PubMed Central (United Kingdom)

BackgroundOver the past decade, many investigators have used sophisticated time series tools for the analysis of genomic sequences. Specifically, the correlation of the nucleotide...Full Text Available

UK PubMed Central (United Kingdom)

The product-operator formalism is the most commonly used tool for describing and designing multidimensional NMR experiments. In spite of its relative simplicity and sound theoretical underpinnings,...Full Text Available

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... Missionaries and cannibals [MaC] (Newell, McDermott and Forgy, 1977, p. 63): Three missionaries and three cannibals must cross a river in a two ...

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monitoring of open pit mining operations. INTRODUCTION. Aerial photography has long been a useful tool for geologists. Cameras ...

UK PubMed Central (United Kingdom)

BackgroundHealth service databases of administrative type can be a useful tool for the study of progression of a disease, but the data reported in such sources could be affected...Full Text Available

UK PubMed Central (United Kingdom)

Percutaneous renal biopsy (PRB) is a safe and effective tool in the diagnosis and management of renal disease. It is the gold standard for evaluating renal parenchymal disease. It is both useful for...Full Text Available

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In this paper information about monograph construction is provided and some sample nomographs constructed by the author are included to encourage the use of these tools in operational health physics applications.

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602-906-5555 Important Links Electronic Reading Room HazMat Mgrs Tools Satellite Network Security Procedures Staff Directory Links - Partners Restricted access BLM NTC INTRANET...

UK PubMed Central (United Kingdom)

BACKGROUNDNew diagnostic tools are urgently needed to interrupt the transmission of tuberculosis and multidrug-resistant tuberculosis. Rapid,...Full Text Available

Science.gov (United States)

The introduction of numerical control (NC) machine tools has made it possible to automate machining in series and small series production. The organization of automated production sections merged NC machine tools with automated transport systems. However, both the one and the other require the presence of an operative at the machine for low skilled operations. Industrial robots perform a number of auxiliary operations, such as equipment loading-unloading and control, changing cutting and auxiliary tools, controlling workpieces and parts, and cleaning of location surfaces. When used with a group of equipment they perform transfer operations between the machine tools. Industrial robots eliminate the need for workers to form auxiliary operations. This underscores the importance of developing robotized manufacturing centers providing for minimal human participation in production and creating conditions for ...

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Possible ICE Tools Relationship. within a Business Model ... Established a Joint IV&V Cost Estimating (ICE) Team comprised of Personnel from NASA, ...

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Mar 15, 2011 ... The NASA/JPL Education Office works with educators -- both classroom teachers and informal educators -- to provide tools, resources and ...

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Sep 18, 2009 ... It is proposed to develop desensitized optimal filtering ... in robust and/or adaptive generalized Kalman and Sigma-Point filters for ...

UK PubMed Central (United Kingdom)

BackgroundNucleotide sequences and the gene arrangements of mitochondrial genomes are effective tools for resolving phylogenetic problems. Hemipteroid insects are known to possess...Full Text Available

UK PubMed Central (United Kingdom)

INTRODUCTIONInformatics and automation are important tools for the reduction of work, errors and costs in a hospital pharmacy.OBJECTIVESTo describe...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundAdequate pain assessment is critical for evaluating the efficacy of analgesic treatment in clinical practice and during the development of new therapies. Yet the currently...Full Text Available

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R. J. Schwinghamer: Magnetic Forming in Space,. Astronautics, September 1962, pp . 63-67. Burkhalter & White: New Tools for the Inquisitive ...

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This book presents papers on internal combustion engines. Topics considered include the influence of partial suppression of heat rejection on performance and emissions, duothermic combustion, turbochargers made of sintered silicon nitrides, heat flux, low heat rejection engines, exhaust energy recovery, combustion chamber insulation, computerized simulation, heat transfer, friction, hoop stress effects, and bonding ceramics and metals.

International Nuclear Information System (INIS)

A description is given of sinterable powders and methods of producing sintered products using such powders. The powders consist of (a) a particulate ceramic material, e.g. SiC, having specified particle size and surface area; (b) a carbon source material, e.g. sugar or a phenol-formaldehyde resin; and (c) a residue from a solution of H3BO3, B2O3, or mixtures of these as sintering aid. (U.K.).

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Research investigating applicability of lithium salts for solid electrolyte batteries was described. The studies included determinations of lithium ion conductivities in solid electrolyte systems based on Li4SiO4, LiTi2(PO4)3, and ceramic materials. Research on all solid state lithium cells utilizing TiS2 NiPS3 electrodes was also reported.

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The bibliography contains citations concerning industrial uses and design of microwave heating equipment. Included are heating and drying of paper, industrial process heat, vulcanization, textile processing, metallurgical heat for sintering and ceramic manufacturing, food processing, and curing of polymers.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

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A method for bistable storage of binary optical information includes an antiferroelectric (AFE) lead lanthanum zirconate titanate (PLZT) layer having a stable antiferroelectric first phase and a ferroelectric (FE) second phase obtained by applying a switching electric field across the surface of the device. Optical information is stored by illuminating selected portions of the layer to photoactivate an FE to AFE transition in those portions. Erasure of the stored information is obtained by reapplying the switching field.

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Special Issue on Automotive Bearings and Applicable Products; Reports include Performance of Ceramic Cam Roller Follower for Automotive Engine; Performance of Drawn Cup Needle Roller Bearing for Propellershaft; Plastic Bearing Retainer for High Temperature Oil Lubrication; Bearing Device for Vehicle Axle; and Flush Mounting Type Programmable Cam Switches.

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The concept of a multi-cavity volumetric solar receiver is very attractive for the profitability of certain of its characteristics such as high efficiency and economy. The absorber is based on a pack of small ceramic cavities which intercept and absorb the inherent high solar flux reflected from an array of mirrors. Atmospheric air acts as a coolant medium when it is drawn through the pack. A model for an overall heat transfer performance of the receiver is given and numerically solved.

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This document describes measurements of the directional spectral emittance of four ceramic mold materials. The work was performed with the samples at {approximately} 900{degree}C in a vacuum vessel pumped to {approximately}3 {times} 10{sup {minus}6}Torr. Results conform to expectations derived from prior work done with similar samples.

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In this paper coating developments for advanced gas turbine engines (diffusion aluminide coatings, overlay coatings, and ceramic thermal barrier coatings) were desorbed, a selection of current metallic coatings was made and their performance as outlined. Finally coating developments for advanced diesel engines with a view to improved turbocharging or to low heat rejection engines (adiabatic diesel concept) were dealt with. (IHOE).

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The objective of this work was to identify methods of improving the performance of gas-fired radiant burners through the use of Continuous Fiber Ceramic Composites (CFCCs). Methods have been identified to improve the price and performance characteristics of the porous surface burner. Results are described.

International Nuclear Information System (INIS)

The proactive protection measures and the traditional passive security protection tools are complementarities each other. It also can supply the conventional network security protection system and enhance its capability of the security protection. Based upon sorts of existing network security technologies, this article analyses and summarizes the technologies, functions and the development directions of some key proactive network security protection tools. (authors)

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This report documents the evaluation of risks associated with environmental restoration activities at Brookhaven National Laboratory using two tools supplied by DOE to provide a consistent set of risk estimates across the DOE complex: Risk Data Sheets (RDS) and Relative Risk Ranking. The tools are described, the process taken characterized, results provided and discussed. The two approaches are compared and recommendations provided for continuing improvement of the process.

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The device is made by a tool at the end of a flexible cable, a motor for the rotation of the flexible, a linear drive with a guide for it between the winder and the tube.

British Library Electronic Table of Contents (United Kingdom)

The mechanisms underlying life machinery are still not completely understood. Something is known, something is ?probably? known, other things are still unknown. Scientists all over the world are working very hard to clarify the processes regulating the cell life cycle and bioinformaticians try to support them by developing specialized automated tools. Within the plethora of applications devoted to the study of life mechanisms, tools for the analysis and comparison of biological networks are catching the attention of many researchers. It is interesting to investigate why.

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A start safety apparatus of an engine adapted for a multipurpose power tool is described which consists of: an engine, an exciter coil generating alternate electromotive force in synchronism with rotation of the engine; an ignition coil having primary and secondary windings; a spark plug connected to the secondary winding of the ignition coil; a capacitor connected to the primary winding of the ignition coil the capacitor being charged with a positive half-cycle of the electromotive force; ignition timing control means for controlling discharge of the capacitor; a throttle control latch for setting a throttle valve of the engine in a predetermined throttle angle; a tool driven by the engine; and a centrifugal clutch transferring engine power to the tool when an engine speed exceeds a clutch-in speed.

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Colorectal cancer (CRC) is the most common cause of cancer death among Canadian non-smokers. Each year about 21,500 Canadians are diagnosed with CRC. Ninety percent of cases occur in people aged 50 years or older. An estimated 4,800 Canadian men and 4,100 Canadian women die each year from the disease. About 75% of all new CRC cases arise in people with no known risk factors. Computed tomography colonography (CTC), a cross-sectional imaging examination that permits complete structural examination of the colon, shows promise as a tool for CRC screening. This article reviews the rationale for CRC screening, currently recommended Canadian and American screening guidelines and screening tools, and current evidence supporting CTC as a CRC screening tool and its advantages over conventional screening methods. (author)

British Library Electronic Table of Contents (United Kingdom)

Purpose - The purpose of this paper is to examine potential new uses of return on investment (ROI) in alternative methods for library assessment and valuation. Design/methodology/approach - Uses examples of recent uses of ROI by libraries to identify potential new applications of ROI in library assessment and valuation. Findings - ROI investment has historically been used by libraries for the assessment of past performance of library organizations in a reactive/defensive nature or for assessing the value of customer services. ROI has not been widely used as a proactive assessment tool, to introspectively assess administrative or other internal services, or as an offensive assessment and valuation tool, especially for intangible performance assessment and valuation. Originality/value - New ...

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This paper deals with the externally coal-fired combined cycle (EFCC). A process simulation for different configurations of the EFCC-process is carried out as well as an investigation of the effect of the key parameters such as the gas turbine inlet temperature and the compressor intake airflow. The results show a promising potential of the efficiency. One component of this combined gas and steam turbine cycle is a high temperature heat exchanger that has to withstand the extrem chemical and thermal operating conditions. Fibre reinforced ceramics and combinations of them with monolithic ceramics seem to be the most promising materials for this application. A cost estimating of the EFCC-process shows that a competitive operation should be possible. (orig.) [Deutsch] Die Ergebnisse der Prozesssimulationen weisen ein vielversprechendes Wirkungsgradpotential des extern kohlebefeuerten Gasturbinenprozesses auf. Der fuer dieses neue Kraftwerkskonzept ...

International Nuclear Information System (INIS)

Carbothermal reduction-nitridation (CRN) of SiO_2 is an attractive method for manufacturing Si_3N_4 powders with controlled grain morphology. Moreover, #beta#-sialon powders could also be synthesized from either pure powder mixtures or some inexpensive raw minerals by CRN. The resultant powders have shown some advantages, especially in manufacturing sialon products at low cost. However, there have been only a few works on preparing #alpha#-sialon powders. In this work, Ca-#alpha# sialon powder was synthesized by CRN of a SiO_2-Al_2O_3 and CaCO_3 powder mixture An unusual morphology of hollow balls of 200 to 500nm with many nano size #alpha#-sialon particles of 10 to 30nm was identified from the resultant Ca-#alpha# sialon powders. This has never been previously reported for sialon ceramics. It was consequently confirmed that the morphologies of the products were clearly related to the intermediate products appearing during CRN reaction. Copyright (2000) The ...

International Nuclear Information System (INIS)

Nitrogen-rich Ca-#alpha#-sialon ceramics, prepared with CaH_2 as one of the starting powders, were compressively deformed in spark plasma sintering equipment. Compared with the oxygen-rich Ca-#alpha#-sialons, increasing onset deformation temperatures (about 150 K higher) were observed for nitrogen-rich Ca-#alpha#-sialons deformed at a rate of 2 x 10"-"3 s"-"1. High hardness (H_V_1_0 = 18-20 GPa) and toughness (K_I_C = 4-7 MPa m"1"/"2) were maintained after the deformation. Anisotropic grain growth was found to take place during deformation, resulting in anisotropic microstructures, containing coarse and elongated grains. The observed differences in deformation behaviour and properties between nitrogen-rich and oxygen-rich Ca-#alpha#-sialons are, as indicated by transmission electron microscopy and electron energy loss spectroscopy analysis, attributed to the presence of reduced amounts of a nitrogen-rich grain-boundary glass phase.

Energy Technology Data Exchange (ETDEWEB)

Study was made on the city bus driven by the series hybrid system composed of a small ceramic gas turbine (100kW), generator and lead storage battery. Two driving modes were adopted, 10-driving mode and real driving mode assuming a certain bus route in Tokyo. The motor is driven mainly by generated power and additionally by battery power, however, the engine/generator system is controlled at an optimum operation point (driving mode and regenerating mode) with a maximum thermal efficiency considering depth of discharge. Design voltage of the battery had nearly no effect on fuel consumption, while its capacity as large as possible was desirable unless its weight has an adverse effect on the system. The real driving mode was lower in fuel consumption by 39% than the 10-driving mode. Since real fuel consumption is largely affected by recovery rate of regenerable energy, the operation point of the motor should be optimized according to driving mode. Fuel consumption at ...

Energy Technology Data Exchange (ETDEWEB)

The goal of this project was to demonstrate that a new low-expanding ceramic (Ca{sub 0.6},Mg{sub 0.4})Zr{sub 4}(PO{sub 4}){sub 6}, hereafter referred to as CMZP, could be used as an exhaust manifold liner in off-road diesel engines and provide improved engine efficiency (by permitting higher engine operating temperature). This study has successfully demonstrated this improvement and further engine testing (and possible manufacturing) is presently underway at Caterpillar Inc. Laboratories. Basically this program involved two subcontracts: one to Virginia Tech to develop sintering procedures for CMZP, and one to Caterpillar, Inc. to develop slip casting procedures for CMZP. Nearly 100kg of CMZP were prepared by MATVA, Inc. and Virginia Tech for use by Caterpillar. Virginia Tech developed detailed sintering procedures for CMZP and Caterpillar developed slip casting procedures and manufactured several exhaust manifold elbows. These elbows have been cast into prototype ...

International Nuclear Information System (INIS)

Within the framework of a study on the chemical wear behaviour of sialon ceramics a range of compositions were prepared in which the alumina content was varied from 6 to 77 weight percent. The materials were hot-pressed from alumina and silicon nitride powders to a density of at least 97%. The structure and compositions of the phases occurring in these samples i.e. the O' phase, #beta#'-sialon solid solution and especially the X-phase were thoroughly characterized with respect to structure and composition using electron microprobe and transmission electron microscopy techniques. These results will be discussed in the light of earlier phase diagram studies. Some basic properties such as E-modulus and toughness were measured and related to microstructural features. E-modulus as well as toughness are at a minimum for materials with a high content of the X-phase. Oxidation of the materials was studied at 1300 deg C and 1450 deg C using weight gain measurements and ...

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Microwaves were used to induce self-propagating high temperature synthesis (SHS) in the reaction 3TiO{sub 2}+3C+(4+x)Al {yields} 3TiC+2Al{sub 2}O{sub 3}+xAl. The SHS process was studied for x = 0 and 4, using slow and fast heating rates and with and without the application of uniaxial pressure. Less than 50 watts was required to internally ignite the samples using a TE{sub 102} microwave cavity mode. Uniaxial stresses in the range of 200-1400 psi were continuously applied along the vertical axis of some of the processed samples as the SHS reactions were initiated. SEM photomicrographs clearly indicate differences in the formation of whiskers and other microstructural features in the products obtained from microwave and conventional hot wire techniques. The x = 0 samples processed with fast and slow microwave heating rates reached higher densities than the conventionally processed samples.

British Library Electronic Table of Contents (United Kingdom)

The glasses with the composition of 37.5Li2O?(25?x)Fe2O3?xNb2O5?37.5P2O5 (mol%) (x=5,10,15) are prepared, and it is found that the addition of Nb2O5 is effective for the glass formation in the lithium iron phosphate system. The glass?ceramics consisting of Nasicon-type Li3Fe2(PO4)3 crystals with an orthorhombic structure are developed through conventional crystallization in an electric furnace, showing electrical conductivities of 3?10?6?Scm?1 at room temperature and the activation energies of 0.48?eV (x=5) and 0.51?eV (x=10) for Li+ ion conduction in the temperature range of 30?200??C. A continuous wave Nd:YAG laser (wavelength: 1064?nm) with powers of 0.14?0.30?W and a scanning speed of 10??m/s is irradiated onto the surface of the glasses, and the formation of Li3Fe2(PO4)3 crystals is c...

International Nuclear Information System (INIS)

Protonic ceramic membrane fuel cells (PCMFCs) based on proton-conducting electrolytes have attracted much attention because of many advantages, such as low activation energy and high energy efficiency. A stable, easily sintered perovskite oxide BaCe_0_._5Zr_0_._3Y_0_._1_6Zn_0_._0_4O_3_-_#delta# (BCZYZ) as electrolyte for proton-conducting solid oxide fuel cells (SOFCs) with Sm_0_._5Sr_0_._5CoO_3_-_#delta# (SSC) composite cathode is investigated. By fabricating thin membrane BCZYZ electrolyte (#approx#20 #mu#m) synthesized by a modified Pechini method on NiO-BCZYZ anode support, PCMFCs are assembled and tested by selecting SSC perovskite cathode with high mixed ionic and electronic conductivities. An open-circuit potential of 1.015 V, a maximal power density of 528 mW cm"-"2, and a low polarization resistance of the electrodes of 0.15 #OMEGA# cm"2 is achieved at 700 "oC. The results indicate that BCZYZ proton-conducting electrolyte with SSC cathode is a promising ...