WorldWideScience

Sample records for based ceramic tile

  1. Online Detection Approach for Rectangle Ceramic Tile Based on Sequenced Scenery Image

    OpenAIRE

    Yang Lei; Yanjun Li; Liyang Liu; Wei Liu

    2013-01-01

    Image based ceramic tile detection is a way to labor liberation in the production process of ceramic tile. Shapes of ceramic tiles studied in this study are rectangle with different sizes. Many existed researches are based on a situation that only a piece of tile goes through special rail one time, resulting in one or less piece of tile hold in the image from CCD sensor. But in fact, multiple tiles with the same sizes run in a row simultaneously at most factories’ rails, and a 'scenery' image...

  2. Online Detection Approach for Rectangle Ceramic Tile Based on Sequenced Scenery Image

    Directory of Open Access Journals (Sweden)

    Yang Lei

    2013-06-01

    Full Text Available Image based ceramic tile detection is a way to labor liberation in the production process of ceramic tile. Shapes of ceramic tiles studied in this study are rectangle with different sizes. Many existed researches are based on a situation that only a piece of tile goes through special rail one time, resulting in one or less piece of tile hold in the image from CCD sensor. But in fact, multiple tiles with the same sizes run in a row simultaneously at most factories’ rails, and a 'scenery' image is obtained from CCD sensor. And the image processing method based on close-up images is not satisfied in such cases. To detect different rectangle ceramic tiles online according to a sequence of scenery images, this study provide a vector corner method to decide the rectangle tiles with known size information, and a valley detection method via key-image-frames strategy to distinguish the first row in images. Finally, our Online Approach for Rectangle Tile Detection (OARTD was embedded into a detection system and applied to a factory; testing results validated its good performance. Indeed, the use of such an automatic system, to control a tile plant for shape classifying has a good prospect.

  3. TECHNOLOGICAL PROPERTIES OF RAW CLAY BASED CERAMIC TILES: INFLUENCE OF TALC

    Directory of Open Access Journals (Sweden)

    MOUSTAPHA SAWADOGO

    2014-11-01

    Full Text Available Local clay from Burkina Faso has been used as a basic raw material in the formulation of ceramic tile with a natural talc (0 - 4% wt as a flux. The used sintering temperatures are between 950 and 1100 °C with one hour as hold at heating rate of 5 °C∙min-1. The different technological properties (shrinkage, water absorption and mechanical strength are improved when the sintering temperature exceeds 1000 °C. The mixture with 4% wt of talc provides better properties than the other grades. The tiles obtained at 1050 °C with 4% wt of talc have similar characteristics to those obtained at 1100 °C without talc. An energy gain with a difference of temperature of 50 °C could be made with the use of talc as the adjuvant.

  4. Research on Variable Structure Parametric Design System of Ceramic Tile Mould Based on Modular

    Institute of Scientific and Technical Information of China (English)

    DAI Xiao-bo; DONG Yu-de; QIN Lei

    2014-01-01

    To solve the existing problems during the ceramic mold enterprises product design and development process, the variable structure parametric design system based on modular of ceramic mold has been developed. The system uses the object-oriented technology and top-down design concept as a guide, establishes a ceramic mold parametric design process, divides the process of ceramic mold design into modules of different levels and creates a component model library based on the functional analysis. Expanding modular thinking to parts structure design level is an effective solution to the difficulty of changing the structure during the product design process. Examples show that the system can achieve a ceramic mold product design, improve design efficiency.

  5. Ceramic tile glazes: design, trends and applications

    Energy Technology Data Exchange (ETDEWEB)

    Manfredini, T. [Modena Univ. (Italy). Faculty of Engineering

    2002-07-01

    The purpose of this lecture is to describe the state of the art of glazes for applications in ceramic tile industry. A glaze for application in ceramic tile industry must satisfy certain requirements, which may be divided into two large groups, one in relation to its preparation and industrial utilisation and the other specific of the product utilisation. In order to design glaze compositions certain aspects must be taken into account. Viscosity and surface tension of the melt matching the body requirements, linear thermal expansion, nucleation and crystal growth processes occurring during firing, durability and optical properties must be designed and adjusted in the industrial practice. Glass-ceramic systems are the more suitable compositions for innovative glazes for fast firing of wall and floor tiles. (orig.)

  6. Crystallisation of a zirconium-based glaze for ceramic tiles coatings

    OpenAIRE

    Romero, Maximina; Rincón López, Jesús María; Acosta, Anselmo

    2003-01-01

    The effect of iron oxide content on the crystallisation of a zirconium-based glass-ceramic glaze was investigated using a glass-ceramic “white of zirconium” frit and a granite waste glass. Measurements by X-ray diffraction (XRD) combined with scanning electron microscopy (SEM) and EDX microanalysis showed that Fe2O3 gives rise to the crystallisation of an iron-zinc ferrite, which is acting as nucleating agent of feather-like crystals of pyroxene while granite frit enhances the partial dissolu...

  7. Ballistic performance of polyurea-coated armor grade ceramic tiles

    Science.gov (United States)

    Samiee, Ahsan; Isaacs, Jon; Nemat-Nasser, Sia

    2010-04-01

    The use of ceramics as energy absorbents has been studied by many researchers and some improvements in the ballistic performance of ceramic tiles have been made by coating them with different classes of materials (e.g. E-glass/epoxy, carbon-fiber/epoxy, etc.). Using ceramics for energy absorbing applications leads to a significant weight reduction of the system. Therefore, any modification to the ceramic configuration in the system which leads to more energy absorption with the same or less areal density is significant. On the other hand, polyurea has been proved to be an excellent energy dissipating agent in many applications. Inspired by this, we are studying the effect of coating ceramics with polyurea and other materials, on the energy absorption and ballistic performance of the resulting ceramic-based composites. In this study, we investigate the effect of polyurea on ballistic efficiency of ceramic tiles. To this end, we have performed a set of penetration tests on polyurea-ceramic composites. In our experiments, a high velocity projectile is propelled to impact and perforate the ceramic-polyurea composite. The velocity and mass of the projectile are measured before and after the penetration. The change in the kinetic energy of the projectile is evaluated and compared for different polyurea-ceramic configurations (e.g., polyurea on front face, polyurea on back face, polyurea between two ceramic tiles, etc.). The experimental results suggest that polyurea is not as effective as other restraining materials such as E-glass/epoxy and carbon-fiber/epoxy.

  8. Environmental performance of ceramic tiles: Improvement proposals

    International Nuclear Information System (INIS)

    Ceramic tile is one of the most widely used materials in construction. Due to the increased demand for environmentally responsible construction and the ever more restrictive environmental requirements derived from the legislation, there is a need for a tool to enable the environmental behaviour of such material to be evaluated. By the application of the life cycle assessment (LCA) methodology, this study is focused on calculating indicators capable of measuring the environmental behaviour of ceramic tiles. Taking the production of 1 m2 of ceramic as a functional unit, the aim was to perform a life cycle inventory that covers all the stages from mining the red clay and atomising it to glaze manufacture and the production of the ceramic tiles and their delivery to customers. Next, the stages/materials/processes that have the greatest impact were identified, and a series of improvements were proposed with a view to enhancing the energetic efficiency of the firing process and minimising the emissions into the atmosphere, while at the same time reducing the noise pollution resulting from the pressing process. The environmental and economic feasibility of such a improvements was also studied.

  9. Preparation of high performance ceramic tiles using waste tile granules and ceramic polishing powder

    Institute of Scientific and Technical Information of China (English)

    WANG Gong-xun; SU Da-gen

    2008-01-01

    This paper presents an innovative approach to reusing waste tile granules (TG) and ceramic polishing powder (PP) to produce high performance ceramic tiles. We studied formulations each with a TG mass fraction of 25.0% and a different PP mass fraction between 1.0% and 7.0%. The formulations included a small amount of borax additive of a mass fracton between 0.2%and 1.2%. The effects of these industrial by-products on compressive strength, water absorption and microstructure of the new ceramic tiles were investigated. The results indicate that the compressive strength decreases and water absorption increases when TG with a mass fraction of 25.0% are added. Improvement of the compressive strength may be achieved when TG (up to 25.0%)and PP (up to 2.0%) are both used at the same time. In particular, the compressive strength improvement can be maximized and water absorption reduced when a borax additive of up to 0.5% is used as a flux. Scanning electron microscopy reveals that a certain amount of fine PP granules and a high content of fluxing oxides from borax avail the formation of glassy phase that fills up the pores in the new ceramic tiles, resulting in a dense product with high compressive strength and low water absorption.

  10. Preparation and characterization of photo chromic effect for ceramic tiles

    International Nuclear Information System (INIS)

    Ceramic tile industry is developing due to the technological researches in scientific area and new tiles which are not only a traditional ceramic also have many multiple functionalities have been marketed nowadays. These tiles like photo catalytic, photovoltaic, antibacterial and etc. improve the quality of life and provide lots of benefits such as self cleaning, energy production, climate control. The goal of this study was to enhance the photo chromic function on ceramic tiles which is the attitude of changing color in a reversible way by electromagnetic radiation and widely used in many areas because of its aesthetic and also functional properties. High response time of photo chromic features of ceramic tiles have been achieved by employing of polymeric gel with additives of photoactive dye onto the ceramic surface. Photo chromic layer with a thickness of approximately 45- 50 μm was performed by using spray coating technique which provided homogeneous deposition on surface. Photo chromic ceramic tiles with high photo chromic activity such as reversibly color change between ΔE= 0.29 and 26.31 were obtained successfully. The photo chromic performance properties and coloring-bleaching mechanisms were analyzed by spectrophotometer. The microstructures of coatings were investigated both by stereo microscopy and scanning electron microscopy (SEM). (Author) 13 ref.s

  11. ASSESSMENT OF CERAMIC TILE FROST RESISTANCE BY MEANS OF THE FREQUENCY INSPECTION METHOD

    Directory of Open Access Journals (Sweden)

    MICHAL MATYSÍK

    2011-06-01

    Full Text Available The paper presents some results of our experimental analysis of ceramic cladding element frost resistance, particular attention being paid to the application of the frequency inspection method. Three different sets of ceramic tiles of the Ia class to EN 14 411 B standard made by various manufacturers have been analyzed. The ceramic tiles under investigation have been subjected to freeze-thaw-cycle-based degradation in compliance with the relevant ČSN EN ISO 10545-12 standard. Furthermore, accelerated degradation procedure has been applied to selected test specimens, consisting in reducing the temperature of water soaked ceramic tiles in the course of the degradation cycles down –70°C. To verify the correctness of the frequency inspection results, additional physical properties of the ceramic tiles under test have been measured, such as, the ceramic tile strength limit, modulus of elasticity and modulus of deformability, resulting from the flexural tensile strength tests, integrity defect and surface micro-geometry tracking. It has been proved that the acoustic method of frequency inspection is a sensitive indicator of the structure condition and can be applied to the ceramic cladding element frost resistance and service life prediction assessment.

  12. Dolomite addition effects on the thermal expansion of ceramic tiles

    International Nuclear Information System (INIS)

    The thermal expansion of ceramic tiles is of greater importance in engineering applications because the ceramics are relatively brittle and cannot tolerate large internal strain imposed by thermal expansion. When ceramic bodies are produced for glazed ties the compatibility of this property of the components should be considered to avoid damage in the final products. Carbonates are an important constituent of ceramic wall-title bodies and its presence in formulations and the reactions that occur between them and other components modify body properties. The influence in expansivity by additions of calcium magnesium carbonate in a composition of wall tile bodies has been investigated. The relative content of mineralogical components was determined by X-ray diffraction and thermal expansion by dilatometric measurements. The results was indicated that with the effect of calcium-magnesium phases and porosity on thermal expansion of wall tile bodies. (author)

  13. Methodology for life cycle assessment of ceramic floor and wall tiles - applications in BAT definition for ceramic tiles industry

    Energy Technology Data Exchange (ETDEWEB)

    Rinaldi, C.; Fregni, A.; Palmonari, C.; Timellini, G. [Centro Ceramico, Bologna (Italy)

    2002-07-01

    In order to manage the new European approach to the protection of the environment, based on the prevention of pollution starting from the design of new products and production techniques, ceramic industries need new specific analysis tools, such as life cycle assessment. A Life Cycle Assessment procedure specific for ceramic tiles industry has been developed [1] and used to compare the environmental performances of different products and technologies. Attention has been focused, in particular, on techniques having cross media effects (for example, the purification of gaseous emissions and cogeneration). The identification and quantification of the possible environmental benefits or risks associated to these techniques, enable the development of design criteria for measures intended to achieve an integrated pollution prevention and reduction, and thus a global protection of the whole environment. (orig.)

  14. Synthetic flux as a whitening agent for ceramic tiles

    International Nuclear Information System (INIS)

    Highlights: • The synthetic flux acts as a whitening agent of firing color in raw material ceramics. • The raw material ceramics have high levels of the iron oxides and red color. • The different process obtained red color clays with hematite and illite phases. • The whiteness ceramic obtained herein can be used in a porcelain tile industry. - Abstract: A synthetic flux is proposed as a whitening agent of firing color in tile ceramic paste during the sinterization process, thus turning the red firing color into whiteness. By using this mechanism in the ceramic substrates, the stoneware tiles can be manufactured using low cost clays with high levels of iron oxides. This method proved to be an economical as well as commercial strategy for the ceramic tile industries because, in Brazil, the deposits have iron compounds as mineral component (Fe2O3) in most of the raw materials. Therefore, several compositions of tile ceramic paste make use of natural raw materials, and a synthetic flux in order to understand how the interaction of the iron element, in the mechanism of firing color ceramic, occurs in this system. The bodies obtained were fired at 1100 °C for 5 min in air atmosphere to promote the color change. After the heating, the samples were submitted to X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) analyses. The results showed that the change of firing color occurs because the iron element, which is initially in the crystal structure of the hematite phase, is transformed into a new crystal (clinopyroxenes phase) formed during the firing, so as to make the final firing color lighter

  15. Influence of Polymer Restraint on Ballistic Performanceof Alumina Ceramic Tiles

    Directory of Open Access Journals (Sweden)

    P.R.S. Reddy

    2008-03-01

    Full Text Available An experimental study has been carried out to evaluate the influence of confinement ofalumina ceramic tiles through polymer restraint, on its ballistic performance. Tiles of 99.5 per centpurity alumina were subjected to ballistic impact against 7.62 mm armour piercing projectiles atvelocities of about 820 m/s. The tiles of size 75 mm x 75 mm x 7 mm were confined on both facesby effectively bonding varying numbers of layers of polymer fabrics. These were then bondedto a 10 mm thick fibre glass laminate as a backing using epoxy resin. High performance polyethyleneand aramid polymer fabrics were used in the current set of experiments for restraining the tiles.Comparative effects of confinement on energy absorption of tiles with varied number of layersof fabrics were evaluated. It was observed that by providing effective confinement to the tile,energy absorption could be doubled with increase in areal density by about 13 per cent.Photographs of the damage and the effects of restraint on improvement in energy absorptionof ceramic tiles are presented and discussed.

  16. Military Curriculum Materials for Vocational and Technical Education. Builders School, Ceramic Tile Setting 3-9.

    Science.gov (United States)

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This course, for individualized or group instruction on ceramic tile setting, was developed from military sources for use in vocational education. The course provides students with skills in mortar preparation, surface preparation, tile layout planning, tile setting, tile cutting, and the grouting of tile joints. Both theory and shop assignments…

  17. Tantalum-Based Ceramics for Refractory Composites

    Science.gov (United States)

    Stewart, David A.; Leiser, Daniel; DiFiore, Robert; Kalvala, Victor

    2006-01-01

    A family of tantalum-based ceramics has been invented as ingredients of high-temperature composite insulating tiles. These materials are suitable for coating and/or permeating the outer layers of rigid porous (foam-like or fibrous) ceramic substrates to (1) render the resulting composite ceramic tiles impervious to hot gases and (2) enable the tiles to survive high heat fluxes at temperatures that can exceed 3,000 F ( 1,600 C).

  18. Composite definition features using the eastern ornament in ceramic tiles

    OpenAIRE

    Uss, V. F.; National Aviation University, Kyiv, Ukraine; Sahno, K. S.; National Aviation University, Kyiv

    2013-01-01

    This paper was asked a series of questions for the study of composition of the artistic shaping of ceramic tile with oriental ornaments and how to use in interior design. Particular attention is paid to individual elements of ornament and use them in areas such as kitchens, bathrooms, hookah area, cafe and more.

  19. Electrokinetic desalination of glazed ceramic tiles

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Ferreira, Celia; Christensen, Iben Vernegren

    2010-01-01

    contaminated with NaCl during submersion and subsequently desalinated by the method, the desalination was completed in that the high and problematic initial Cl(-) concentration was reduced to an unproblematic concentration. Further conductivity measurements showed a very low conductivity in the tile after...

  20. Modelling the viscoelasticity of ceramic tiles by finite element

    Science.gov (United States)

    Pavlovic, Ana; Fragassa, Cristiano

    2016-05-01

    This research details a numerical method aiming at investigating the viscoelastic behaviour of a specific family of ceramic material, the Grès Porcelain, during an uncommon transformation, known as pyroplasticity, which occurs when a ceramic tile bends under a combination of thermal stress and own weight. In general, the theory of viscoelasticity can be considered extremely large and precise, but its application on real cases is particularly delicate. A time-depending problem, as viscoelasticity naturally is, has to be merged with a temperature-depending situation. This paper investigates how the viscoelastic response of bending ceramic materials can be modelled by commercial Finite Elements codes.

  1. Automatic Defect Detection and Classification Technique from Image: A Special Case Using Ceramic Tiles

    CERN Document Server

    Rahaman, G M Atiqur

    2009-01-01

    Quality control is an important issue in the ceramic tile industry. On the other hand maintaining the rate of production with respect to time is also a major issue in ceramic tile manufacturing. Again, price of ceramic tiles also depends on purity of texture, accuracy of color, shape etc. Considering this criteria, an automated defect detection and classification technique has been proposed in this report that can have ensured the better quality of tiles in manufacturing process as well as production rate. Our proposed method plays an important role in ceramic tiles industries to detect the defects and to control the quality of ceramic tiles. This automated classification method helps us to acquire knowledge about the pattern of defect within a very short period of time and also to decide about the recovery process so that the defected tiles may not be mixed with the fresh tiles.

  2. Energy saving in ceramic tile kilns: Cooling gas heat recovery

    International Nuclear Information System (INIS)

    A great quantity of thermal energy is consumed in ceramic tile manufacture, mainly in the firing stage. The most widely used facilities are roller kilns, fuelled by natural gas, in which more than 50% of the energy input is lost through the flue gas and cooling gas exhaust stacks. This paper presents a calculation methodology, based on certain kiln operating parameters, for quantifying the energy saving obtained in the kiln when part of the cooling gases are recovered in the firing chamber and are not exhausted into the atmosphere. Energy savings up to 17% have been estimated in the studied case. Comparison of the theoretical results with the experimental data confirmed the validity of the proposed methodology. The study also evidenced the need to improve combustion process control, owing to the importance of the combustion process in kiln safety and energy efficiency. - Highlights: •Some energy input (30–35%) in ceramic roller kilns is lost through the cooling gas stack. •Cooling air is directly recovered in the combustion chamber, providing oxygen. •This energy recovery from the cooling gas stack has been quantified. •It has been proven that the proposed methodology to estimate energy savings is valid

  3. 基于机器视觉的随机纹理瓷砖的分选系统%Classification System of Random Texture Ceramic Tiles Based on Machine Vision

    Institute of Scientific and Technical Information of China (English)

    焦亮; 胡国清; Jahangir Alam SM

    2016-01-01

    针对日益加快的瓷砖生产速度与缓慢的人工分选速度之间不协调导致的瓷砖出产效率低下的问题,提出了以机器视觉软件HALCON 11.0为软件开发平台的结合瓷砖颜色、纹理特征提取的算法,以及针对多分类问题的改进多层感知器神经网络算法(MLPNN).首先对拍摄到的瓷砖图像进行去噪预处理,在HSI颜色空间中提取瓷砖的色调(Hue)特征并计算反映瓷砖的纹理特征的灰度共生矩阵(GLCM)和灰度幅值分布特征,再将得到的特征作为多层感知器的神经网络输入层神经元,然后设计以softmax为激活函数的多层感知器神经网络来进行模式匹配,并与BP神经网络模式匹配方法进行对比,最终搭建出具有简单人机交互界面的随机纹理瓷砖的分选实验样机.实验结果表明:本系统对实验的各类随机纹理瓷砖的分选准确率都在90%以上,具有较高的分选准确率,能应用于瓷砖生产实践.%Aiming at the problem of poor efficiency of ceramic tile production caused by the mismatch between higher and higher speed of production and slow speed of artificial classification, the paper presented an algorithm about extracting the features of color and texture of ceramic tiles and an algorithm about improved multilayer perceptron neural network (MLPNN) aiming at the problem of multi-classification based on machine vision software, HALCON 11.0, as the development platform. Firstly, the images of ceramic tiles were denoised as pretreatment. Then the system extracted the hue features of ceramic tiles in HSI color space, calculated the gray level co-occurrence matrix (GLCM) and gray level characteristics of amplitude distribution to reflect the texture feature of ceramic tiles, and put the features as input layer neurons of multilayer perceptron neural network. Next, the paper designed the multilayer perceptron neural network with putting softmax function as the activation for pattern matching, and

  4. Evaluation of the thermal comfort of ceramic floor tiles

    Directory of Open Access Journals (Sweden)

    Carmeane Effting

    2007-09-01

    Full Text Available In places where people are bare feet, the thermal sensation of cold or hot depends on the environmental conditions and material properties including its microstructure and crustiness surface. The uncomforting can be characterized by heated floor surfaces in external environments which are exposed to sun radiation (swimming polls areas or by cold floor surfaces in internal environments (bed rooms, path rooms. The property named thermal effusivity which defines the interface temperature when two semi-infinite solids are putted in perfect contact. The introduction of the crustiness surface on the ceramic tiles interferes in the contact temperature and also it can be a strategy to obtain ceramic tiles more comfortable. Materials with low conductivities and densities can be obtained by porous inclusion are due particularly to the processing conditions usually employed. However, the presence of pores generally involves low mechanical strength. This work has the objective to evaluate the thermal comfort of ceramics floor obtained by incorporation of refractory raw materials (residue of the polishing of the porcelanato in industrial atomized ceramic powder, through the thermal and mechanical properties. The theoretical and experimental results show that the porosity and crustiness surface increases; there is sensitive improvement in the comfort by contact.

  5. Real-time surface grading of ceramic tiles

    OpenAIRE

    López García, Fernando

    2008-01-01

    This thesis presents a case of study of the development and performance analysis of a surface grading application with real-time compliance. We address the issue of spatial and temporal uniformity in the acquisition system. In a surface grading application it is crucial to ensure the uniform response of the system through time and space. All the results presented for surface grading were obtained using real data from the ceramic tile industry. The VxC TSG database is public and can be...

  6. Oven atmosphere influence on the defects elimination in tile ceramics

    International Nuclear Information System (INIS)

    Ceramic tiles show defects after firing due to reaction of transition metals with atmosphere at high temperatures. These defects (differential colors at surface) can be eliminated by skin atmosphere control. Test samples obtained from industrial composition with addition of transition metal oxides were heat treated in different atmospheres. The samples were analysed by X-ray diffraction, scanning electron microscopy and thermal analysis to evaluate the effect of transition metals and firing atmosphere in defect formation. The results showed that skin atmosphere and organic matter concentration play an important role in the differential color formation due to transition metals reduction or metal carbide formation. (author)

  7. The Economic crisis and immigration: Romanian citizens in the ceramic tile district of Castello (Spain)

    OpenAIRE

    Joan Serafí BERNAT; Viruela, Rafael

    2011-01-01

    Between 2001 and 2007 an exceptional number of immigrants arrived in the province of Castelló (Spain), the majority of whom were from Romania, attracted by the plentiful employment prospects offered by a model of production based on the intensive labour requirements of the ceramic tile and construction industries. The effects of the international economic crisis have been particularly serious in the area of Castelló, where employment has fallen by 20% in just three years. Immigrations flow...

  8. Thermoluminescence study of materials (natural minerals) used in ceramic tiles industry

    International Nuclear Information System (INIS)

    Mother earth is giving many materials in the natural form as well as in mineral form. Among them the marbles, granites and other variety of slabs for house hold flooring purposes. The people demand for variety of flooring materials leads to develop various types of ceramic tile. In India ceramic tiles industry is one of the fast growing one. More than two hundred units are manufacturing the ceramic tiles situated around Morbi, Rajkot, Gujarat, India. The basic raw materials required for manufacturing the various types of ceramic tiles are natural minerals. The following are the minerals used to manufacture the ceramic tiles i.e. quartz, feldspar, zircon, china clay, talc, grok, Aluminum oxide etc.,

  9. Decorative design of ceramic tiles adapted to inkjet printing employing digital image processing

    International Nuclear Information System (INIS)

    The ceramic tile sector is a very competitive industry. The designer's proficiency to offer new models of the decorated surface, adapted to the production means, plays a very important role in the competitiveness. In the present work, we analyze the evolution of the design process in the ceramic sector, as much as the changes experimented in parallel by the printing equipment. Afterwards, we present a new concept of ceramic design, based on digital image processing. This technique allows the generation of homogeneous and non-repetitive designs for large surfaces, especially thought for inkjet printing. With the programmed algorithms we have compiled a prototype software for the assistance of the ceramic design. This tool allows creating continuous designs for large surfaces saving developing time. (Author)

  10. Structural and Thermomechanical Properties of Stove Tile Ceramics

    Directory of Open Access Journals (Sweden)

    Anton TRNÍK

    2013-12-01

    Full Text Available The thermomechanical and thermodilatometric behavior of fired heatproof stove tile ceramic material Letovice, which contains quartz, mullite and small amounts of feldspar and glassy phase, was studied while increasing temperature up to 1100 °C. Young’s modulus was measured using the non-destructive sonic resonant method mf-TMA. To find actual dimensions of the sample, thermodilatometry was carried out at the same temperature regime as mf-TMA. A significant increase in Young’s modulus was observed in the region of the α ® b transformation of quartz. This can be explained by the healing effect of the induced radial stresses around the quartz grains on microcracks. The presence of glassy phase caused a small decrease of Young’s modulus at temperatures above ~950 °C. DOI: http://dx.doi.org/10.5755/j01.ms.19.4.2916

  11. Chemical functionalization of ceramic tile surfaces by silane coupling agents: polymer modified mortar adhesion mechanism implications

    Directory of Open Access Journals (Sweden)

    Alexandra Ancelmo Piscitelli Mansur

    2008-09-01

    Full Text Available Adhesion between tiles and mortars are crucial to the stability of ceramic tile systems. From the chemical point of view, weak forces such as van der Waals forces and hydrophilic interactions are expected to be developed preferably at the tiles and polymer modified Portland cement mortar interface. The main goal of this paper was to use organosilanes as primers to modify ceramic tile hydrophilic properties to improve adhesion between ceramic tiles and polymer modified mortars. Glass tile surfaces were treated with several silane derivatives bearing specific functionalities. Contact angle measurements and Fourier Transform Infrared Spectroscopy (FTIR were used for evaluating the chemical changes on the tile surface. In addition, pull-off tests were conducted to assess the effect on adhesion properties between tile and poly(ethylene-co-vinyl acetate, EVA, modified mortar. The bond strength results have clearly shown the improvement of adherence at the tile-polymer modified mortar interface, reflecting the overall balance of silane, cement and polymer interactions.

  12. Synthesis, deposition and crystal growth of CZTS nanoparticles onto ceramic tiles

    OpenAIRE

    Calvet Roures, Iván; Barrachina Albert, Ester; Martí Valls, Rafael Francisco; Fraga Chiva, Diego; Stoyanova Lyubenova, Teodora; Carda Castelló, Juan B.

    2015-01-01

    The work presents a simple solvothermal method for CZTS nanoparticles preparation using hexadecylamine (HDA) as a capping agent. The as-prepared CZTS powder was deposited as ink using Doctor Blade technique onto ceramic tile, as a substrate substituting the typical soda-lime glass. The as-prepared film was thermal treated at different temperatures in order to enhance the thin film crystallinity. CZTS crystal growth onto ceramic tile was obtained successfully for the first time. En el traba...

  13. Installation of Ceramic Tile: Residential Thin-Set Methods.

    Science.gov (United States)

    Short, Sam

    This curriculum guide contains materials for use in teaching a course on residential thin-set methods of tile installation. Covered in the individual units are the following topics: the tile industry; basic math; tools; measurement; safety in tile setting; installation materials and guidelines for their use; floors; counter tops and backsplashes;…

  14. Optimal Non-Invasive Fault Classification Model for Packaged Ceramic Tile Quality Monitoring Using MMW Imaging

    Science.gov (United States)

    Agarwal, Smriti; Singh, Dharmendra

    2016-04-01

    Millimeter wave (MMW) frequency has emerged as an efficient tool for different stand-off imaging applications. In this paper, we have dealt with a novel MMW imaging application, i.e., non-invasive packaged goods quality estimation for industrial quality monitoring applications. An active MMW imaging radar operating at 60 GHz has been ingeniously designed for concealed fault estimation. Ceramic tiles covered with commonly used packaging cardboard were used as concealed targets for undercover fault classification. A comparison of computer vision-based state-of-the-art feature extraction techniques, viz, discrete Fourier transform (DFT), wavelet transform (WT), principal component analysis (PCA), gray level co-occurrence texture (GLCM), and histogram of oriented gradient (HOG) has been done with respect to their efficient and differentiable feature vector generation capability for undercover target fault classification. An extensive number of experiments were performed with different ceramic tile fault configurations, viz., vertical crack, horizontal crack, random crack, diagonal crack along with the non-faulty tiles. Further, an independent algorithm validation was done demonstrating classification accuracy: 80, 86.67, 73.33, and 93.33 % for DFT, WT, PCA, GLCM, and HOG feature-based artificial neural network (ANN) classifier models, respectively. Classification results show good capability for HOG feature extraction technique towards non-destructive quality inspection with appreciably low false alarm as compared to other techniques. Thereby, a robust and optimal image feature-based neural network classification model has been proposed for non-invasive, automatic fault monitoring for a financially and commercially competent industrial growth.

  15. Environmental Radioactivity Comparison Study for the Glaze-Clay Surface of Ceramic Tiles by Tracks Technique

    International Nuclear Information System (INIS)

    Tracks Density, radon concentration, radon exhalation rates and radium concentration were measured from ceramic tiles for both of glaze and clay by using the track technique, containing CR-39, to estimate the radiation exposure in the vicinity of ceramic tile. For ceramic tiles of wall, the average of tracks density, the radon concentration, radon exhalation rates and radium concentration were found in the range 230-356 tracks.cm-2, 389-600 Bq.m-3, 21-31 mBq.m-2.h-1, 16-25 Bq.kg-1, respectively. While for ceramic tiles of floor, the average of tracks density, the radon concentration, radon exhalation rates and radium concentration were found in the range 274-509 tracks.cm-2, 463-860 Bq.m-3, 25-46 mBq.m-2.h-1, 19-46 Bq.kg-1, respectively. The average level of radon concentrations caused by these ceramic tiles for Egyptian companies covering both of wall, floor, glaze and clay giving an annual exposure dose 22±2 mSv.y-1 which is higher than internationally recommended range

  16. Enhancing Polymer-Modified Mortar Adhesion to Ceramic Tile Surface by Chemical Functionalization with Organosilanes

    Science.gov (United States)

    Mansur, Alexandra Ancelmo Piscitelli; Do Nascimento, Otávio Luiz; Mansur, Herman Sander

    Adhesion between tiles and mortars is of paramount importance to the overall stability of ceramic tile systems. In this sense, from the chemical perspective, weak forces such as van der Waals forces and hydrophilic interactions are expected to occur preferably at the tiles and polymer-modified Portland cement mortar interfaces. Thus, the main goal of this study was to chemically modify the ceramic tile surface through organosilanes aiming to improve adhesion with polymer-modified mortars (PMMs). Glass tile surfaces were treated with five silane derivatives bearing specific functionalities. Fourier transform infrared spectroscopy and contact angle measurements were used for characterizing the novel surfaces produced as the chemical moieties were immobilized onto them. In addition, pull-off tests were conducted to assess the effect on adhesion properties between tile and poly(ethylene-co-vinyl acetate) modified mortar. The bond strength results have given strong evidence of the improvement on adherence at the tile-PMM interface, reflecting the whole balance of silane, cement, and polymer interactions.

  17. Micro-XRF for characterization of Moroccan glazed ceramics and Portuguese tiles

    International Nuclear Information System (INIS)

    A set of enamelled terracotta samples (Zellij) collected from five different monuments in Morocco were object of study. With the aim of characterizing these typically Moroccan artistic objects, X-ray spectroscopic techniques were used as analytical tool to provide elemental and compound information. A lack of information about these types of artistic ceramics is found by the research through international scientific journals, so this investigation is an opportunity to fulfill this gap. For this purpose, micro-Energy Dispersive X-ray Fluorescence (μ-EDXRF), and wavelength dispersive X-ray Fluorescence (WDXRF) and X-ray Diffraction (XRD) were the chosen methods. As complementary information, a comparison with other sort of artistic pottery objects is given, more precisely with Portuguese glazed wall tiles (Azulejos), based in the Islamic pottery traditions. Differences between these two types of decorative pottery were found and presented in this manuscript.

  18. Ancient Wall Tiles – The Importance of the Glaze/Ceramic Interface in Glaze Detachment

    Directory of Open Access Journals (Sweden)

    Marisa COSTA

    2014-04-01

    Full Text Available One of the most severe pathologies suffered by early industrially produced tiles in Portugal in late nineteenth century is glaze detachment in wall tiles placed in the lower part of the façade. It is known that salts crystallize provoking the glaze detachment, destroying the waterproofing and the beauty of the wall tile and this is one of the crucial factors towards this occurrence. The present work questions the importance of the thickness of glaze/ceramic body interface, in what concerns glaze detachment provoked by salt crystallization. SEM-EDS was used to perform all the observations that lead to the conclusion that the exuberance of the interface between glaze and ceramic body has no influence in the resistance of the glaze to salt crystallization though time, being the porous network more determinant. DOI: http://dx.doi.org/10.5755/j01.ms.20.1.3815

  19. Modelling runoff on ceramic tile roofs using the kinematic wave equations

    Science.gov (United States)

    Silveira, Alexandre; Abrantes, João; de Lima, João; Lira, Lincoln

    2016-04-01

    Rainwater harvesting is a water saving alternative strategy that presents many advantages and can provide solutions to address major water resources problems, such as fresh water scarcity, urban stream degradation and flooding. In recent years, these problems have become global challenges, due to climatic change, population growth and increasing urbanisation. Generally, roofs are the first to come into contact with rainwater; thus, they are the best candidates for rainwater harvesting. In this context, the correct evaluation of roof runoff quantity and quality is essential to effectively design rainwater harvesting systems. Despite this, many studies usually focus on the qualitative aspects in detriment of the quantitative aspects. Laboratory studies using rainfall simulators have been widely used to investigate rainfall-runoff processes. These studies enabled a detailed exploration and systematic replication of a large range of hydrologic conditions, such as rainfall spatial and temporal characteristics, providing for a fast way to obtain precise and consistent data that can be used to calibrate and validate numerical models. This study aims to evaluate the performance of a kinematic wave based numerical model in simulating runoff on sloping roofs, by comparing the numerical results with the ones obtained from laboratory rainfall simulations on a real-scale ceramic tile roof (Lusa tiles). For all studied slopes, simulated discharge hydrographs had a good adjust to observed ones. Coefficient of determination and Nash-Sutcliffe efficiency values were close to 1.0. Particularly, peak discharges, times to peak and peak durations were very well simulated.

  20. Content-Based Tile Retrieval System

    Czech Academy of Sciences Publication Activity Database

    Vácha, Pavel; Haindl, Michal

    Berlin / Heidelberg : Springer Berlin / Heidelberg, 2010 - (Hancock, Edwin and Wilson, Richard and Windeatt, Terry and Ulusoy, Ilkay and Escolano, Francisco), s. 434-443 ISBN 978-3-642-14979-5. ISSN 0302-9743. - (LNCS. 6218). [Structural, Syntactic, and Statistical Pattern Recognition. Cesme, Izmir (TR), 18.08.2010-20.08.2010] R&D Projects: GA MŠk 1M0572; GA ČR GA102/08/0593 Grant ostatní: GA MŠk(CZ) 2C06019 Institutional research plan: CEZ:AV0Z10750506 Keywords : content based image retrieval * textural features * colour * tile classification Subject RIV: BD - Theory of Information http://library.utia.cas.cz/separaty/2010/RO/vacha-content-based tile retrieval system.pdf

  1. Measuring Fracture Times Of Ceramics

    Science.gov (United States)

    Shlichta, Paul J.; Bister, Leo; Bickler, Donald G.

    1989-01-01

    Electrical measurements complement or replace fast cinematography. Electronic system measures microsecond time intervals between impacts of projectiles on ceramic tiles and fracture tiles. Used in research on ceramics and ceramic-based composite materials such as armor. Hardness and low density of ceramics enable them to disintegrate projectiles more efficiently than metals. Projectile approaches ceramic tile specimen. Penetrating foil squares of triggering device activate display and recording instruments. As ceramic and resistive film break oscilloscope plots increase in electrical resistance of film.

  2. LSA glass-ceramic tiles made by powder pressing

    International Nuclear Information System (INIS)

    A low cost alternative for the production of glass-ceramic materials is the pressing of the matrix glass powders and its consolidation simultaneously with crystallization in a single stage of sintering. The main objective of this work was to obtain LSA glass ceramics with low thermal expansion, processed by pressing and sintering a ceramic frit powder. The raw materials were homogenized and melted (1480 deg C, 80min), and the melt was poured in water. The glass was chemically (XRF and AAS) and thermally (DTA, 10 deg C/min, air) characterized, and then ground (60min and 120min). The ground powders were characterized (laser diffraction) and compressed (35MPa and 45MPa), thus forming four systems. The compacts were dried (150 deg C, 24h) and sintered (1175 deg C and 1185 deg C, 10 deg C/min). Finally, the glass-ceramics were characterized by microstructural analysis (SEM and XRD), mechanical behavior (σbending) and thermal analysis (α). The best results for thermal expansion were those for the glass-ceramics processed with smaller particle size and greater compaction pressure. (author)

  3. Tile-based Level of Detail for the Parallel Age

    Energy Technology Data Exchange (ETDEWEB)

    Niski, K; Cohen, J D

    2007-08-15

    Today's PCs incorporate multiple CPUs and GPUs and are easily arranged in clusters for high-performance, interactive graphics. We present an approach based on hierarchical, screen-space tiles to parallelizing rendering with level of detail. Adapt tiles, render tiles, and machine tiles are associated with CPUs, GPUs, and PCs, respectively, to efficiently parallelize the workload with good resource utilization. Adaptive tile sizes provide load balancing while our level of detail system allows total and independent management of the load on CPUs and GPUs. We demonstrate our approach on parallel configurations consisting of both single PCs and a cluster of PCs.

  4. Photocatalytic Removal of Azo Dye and Anthraquinone DyeUsing TiO2 Immobilised on Ceramic Tiles

    OpenAIRE

    P. N. Palanisamy; Kavitha, S. K.

    2011-01-01

    The photocatalytic activity of TiO2 immobilized on different supports; cement and ceramic tile, was studied to decolorize two commercial dyes. The catalyst was immobilised by two different techniques, namely, slurry method on ceramic tile and powder scattering on cement. The degradation of the dyes was carried out using UV and solar irradiation. The comparative efficiency of the catalyst immobilised on two different supports was determined. The photodegradation process was monitored by UV-Vis...

  5. Path-dependency and path-making in the energy system in the spanish ceramic tile cluster; La evolucion energetica del sector espanol de baldosas ceramicas

    Energy Technology Data Exchange (ETDEWEB)

    Monfort, E.; Mezquita, A.; Vaquer, E.; Mallol, G.; Gabaldon-Estevan, D.

    2014-10-01

    This paper analyses how energy consumption and energy efficiency evolved in the Spanish ceramic tile industry in the 20th century and explores the emerging possibilities in the 21st century. In the last century, the tile industry undertook three radical transitions by switching from traditional biomass fuels to liquid hydrocarbon fuels (fuel oil and gas oil), and subsequently to gas fuels, mainly involving natural gas. Although it is difficult to obtain the information that enable the real energy efficiency in manufacturing plants to be reliably evaluated, the available data indicate that a high degree of efficiency has been achieved with current manufacturing technologies. Consequently, significant developments in this sense are not expected, even though efforts are still being made to reduce energy consumption in the production process. However, environmental regulations and impacts, and the emerging new energy sources based on agricultural biomass could open up new avenues for energy supply in the Spanish ceramic tile cluster. (Author)

  6. A review of candidate ceramic materials for use as heat shield tiles in a supercritical-water-cooled-reactor

    International Nuclear Information System (INIS)

    The proposed Canadian supercritical-water-cooled reactor (SCWR) utilizes a reactor shell made of a zirconium alloy insulated with a ceramic tile heat shield. The main consideration in the selection of a tile material will be resistance to corrosion in supercritical water and long term microstructure stability, in addition to thermal conductivity. This paper provides a review of the literature on corrosion behaviours of ceramic materials in supercritical water and ranks candidate ceramic materials accordingly. Materials reviewed include alumina, zirconia, silica glasses, silicon carbide, silicon nitride, sialon, mullite, and aluminum nitride. (author)

  7. Floor tile glass-ceramic glaze for improvement of the resistance to surface abrasion

    Energy Technology Data Exchange (ETDEWEB)

    Gajek, M; Lis, J; Partyka, J; Wojczyk, M, E-mail: mgajek@agh.edu.pl [AGH University of Science and Technology, Faculty of Materials Science and Ceramic, al. Mickiewicza 30, 30-059 Cracow (Poland)

    2011-10-29

    The results of research aimed at the study on frits and glass-ceramic glazes for floor tiles, based on compositions located in the primary field of cordierite crystallization within the system MgO-Al{sub 2}O{sub 3}-SiO{sub 2}, have been presented. The results comprise investigations on the frits crystallization abilities, stability of the crystallizing phase under conditions of single-stage a fast firing cycle (time below 60 minutes) depending on their chemical composition and the influence of the nucleation agents. The influence of the nucleating agents namely TiO{sub 2}, ZrO{sub 2}, V{sub 2}O{sub 5} on phase composition of obtained crystalline glazes, mechanical parameters and microstructure, has been examined. The strength tests proved increased mechanical resistance of crystalline glazes. Obtained glazes are characterized by high microhardness in range 6{approx}8 GPa, as well as the increased wear resistance measured by the loss of weight below 100 mg / 55 cm{sup 2} (PN-EN ISO 10545-7). Significant increase of these parameters as compared with non-crystalline glazes, where micro-hardness values range between 5{approx}6 GPa and the wear resistance values range from 120 to 200 mg, has been proved. Starting glasses (frits) and glazes of the ternary system MgO-SiO{sub 2}-Al{sub 2}O{sub 3}, were examined with use of DTA, XRD and SEM methods.

  8. Floor tile glass-ceramic glaze for improvement of the resistance to surface abrasion

    Science.gov (United States)

    Gajek, M.; Lis, J.; Partyka, J.; Wójczyk, M.

    2011-10-01

    The results of research aimed at the study on frits and glass-ceramic glazes for floor tiles, based on compositions located in the primary field of cordierite crystallization within the system MgO-Al2O3-SiO2, have been presented. The results comprise investigations on the frits crystallization abilities, stability of the crystallizing phase under conditions of single-stage a fast firing cycle (time below 60 minutes) depending on their chemical composition and the influence of the nucleation agents. The influence of the nucleating agents namely TiO2, ZrO2, V2O5 on phase composition of obtained crystalline glazes, mechanical parameters and microstructure, has been examined. The strength tests proved increased mechanical resistance of crystalline glazes. Obtained glazes are characterized by high microhardness in range 6~8 GPa, as well as the increased wear resistance measured by the loss of weight below 100 mg / 55 cm2 (PN-EN ISO 10545-7). Significant increase of these parameters as compared with non-crystalline glazes, where micro-hardness values range between 5~6 GPa and the wear resistance values range from 120 to 200 mg, has been proved. Starting glasses (frits) and glazes of the ternary system MgO-SiO2-Al2O3, were examined with use of DTA, XRD and SEM methods.

  9. Floor tile glass-ceramic glaze for improvement of the resistance to surface abrasion

    International Nuclear Information System (INIS)

    The results of research aimed at the study on frits and glass-ceramic glazes for floor tiles, based on compositions located in the primary field of cordierite crystallization within the system MgO-Al2O3-SiO2, have been presented. The results comprise investigations on the frits crystallization abilities, stability of the crystallizing phase under conditions of single-stage a fast firing cycle (time below 60 minutes) depending on their chemical composition and the influence of the nucleation agents. The influence of the nucleating agents namely TiO2, ZrO2, V2O5 on phase composition of obtained crystalline glazes, mechanical parameters and microstructure, has been examined. The strength tests proved increased mechanical resistance of crystalline glazes. Obtained glazes are characterized by high microhardness in range 6∼8 GPa, as well as the increased wear resistance measured by the loss of weight below 100 mg / 55 cm2 (PN-EN ISO 10545-7). Significant increase of these parameters as compared with non-crystalline glazes, where micro-hardness values range between 5∼6 GPa and the wear resistance values range from 120 to 200 mg, has been proved. Starting glasses (frits) and glazes of the ternary system MgO-SiO2-Al2O3, were examined with use of DTA, XRD and SEM methods.

  10. Process-generated nanoparticles from ceramic tile sintering: Emissions, exposure and environmental release.

    Science.gov (United States)

    Fonseca, A S; Maragkidou, A; Viana, M; Querol, X; Hämeri, K; de Francisco, I; Estepa, C; Borrell, C; Lennikov, V; de la Fuente, G F

    2016-09-15

    The ceramic industry is an industrial sector in need of significant process changes, which may benefit from innovative technologies such as laser sintering of ceramic tiles. Such innovations result in a considerable research gap within exposure assessment studies for process-generated ultrafine and nanoparticles. This study addresses this issue aiming to characterise particle formation, release mechanisms and their impact on personal exposure during a tile sintering activity in an industrial-scale pilot plant, as a follow-up of a previous study in a laboratory-scale plant. In addition, possible particle transformations in the exhaust system, the potential for particle release to the outdoor environment, and the effectiveness of the filtration system were also assessed. For this purpose, a tiered measurement strategy was conducted. The main findings evidence that nanoparticle emission patterns were strongly linked to temperature and tile chemical composition, and mainly independent of the laser treatment. Also, new particle formation (from gaseous precursors) events were detected, with nanoparticles reference value (NRV; 4×10(4)cm(-3)), with 8-hour time weighted average concentrations in the range of 1.4×10(5)cm(-3) and 5.3×10(5)cm(-3). A potential risk for nanoparticle and ultrafine particle release to the environment was also identified, despite the fact that the efficiency of the filtration system was successfully tested and evidenced a >87% efficiency in particle number concentrations removal. PMID:26848012

  11. Quality and seasonal variation of rainwater harvested from concrete, asphalt, ceramic tile and green roofs in Chongqing, China.

    Science.gov (United States)

    Zhang, Qianqian; Wang, Xiaoke; Hou, Peiqiang; Wan, Wuxing; Li, Ruida; Ren, Yufen; Ouyang, Zhiyun

    2014-01-01

    There is an urgent requirement to examine the quality of harvested rainwater for potable and non-potable purposes, based on the type of roofing material. In this study, we examined the effect on the quality of harvested rainwater of conventional roofing materials (concrete, asphalt and ceramic tile roofs) compared with alternative roofing materials (green roof). The results showed that the ceramic tile roof was the most suitable for rainwater-harvesting applications because of the lower concentrations of leachable pollutants. However, in this study, the green roof was not suitable for rainwater harvesting applications. In addition, seasonal trends in water quality parameters showed that pollutants in roof runoff in summer and autumn were lower than those in winter and spring. This study revealed that the quality of harvested rainwater was significantly affected by the roofing material; therefore, local government and urban planners should develop stricter testing programs and produce more weathering resistant roofing materials to allow the harvesting of rainwater for domestic and public uses. PMID:24316751

  12. Integrator based readout in Tile Calorimeter of the ATLAS experiment

    CERN Document Server

    Gonzalez Parra, G

    2012-01-01

    TileCal is the hadronic tile calorimeter of the ATLAS experiment at LHC/CERN. To equalize the response of individual TileCal cells with a precision better than 1 % and to monitor the response of each cell over time, a calibration and monitoring system based on a Cs137 radioactive source driven through the calorimeter volume by liquid flow has been implemented. This calibration system relies on dedicated readout chain based on a slow integrators that read currents from the TileCal photomultipliers integrating over milliseconds during the calibration runs. Moreover, during the LHC collisions the TileCal integrator based readout provides the signal coming from inelastic proton- proton collisions at low momentum transfer (MB) which is used to monitor ATLAS instantaneously luminosity and to continuously monitor the response of all calorimeter cells during data-taking.

  13. Utilization of steel melting electric arc furnace slag for development of vitreous ceramic tiles

    Indian Academy of Sciences (India)

    Ritwik Sarkar; Nar Singh; Swapan Kumar Das

    2010-06-01

    Steel melting through electric arc furnace route is gaining popularity due to its many advantages, but generates a new waste, electric arc furnace slag, which is getting accumulated and land/mine filling and road construction are the only utilization. This slag has been tried to be value added and utilized to develop vitreous ceramic tiles. Slag, to the extent of 30–40 wt% with other conventional raw materials, were used for the development in the temperature range 1100–1150°C. The fired products showed relatively higher density with shorter firing range and good strength properties. Microstructural and EDAX studies were also done to evaluate the developed products.

  14. Standard test method for measurement of light reflectance value and small color differences between pieces of ceramic tile

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This test method covers the measurement of Light Reflectance Value (LRV) and visually small color difference between pieces of glazed or unglazed ceramic tile, using any spectrophotometer that meets the requirements specified in the test method. LRV and the magnitude and direction of the color difference are expressed numerically, with sufficient accuracy for use in product specification. 1.2 LRV may be measured for either solid-colored tile or tile having a multicolored, speckled, or textured surface. For tile that are not solid-colored, an average reading should be obtained from multiple measurements taken in a pattern representative of the overall sample as described in 9.2 of this test method. Small color difference between tiles should only be measured for solid-color tiles. Small color difference between tile that have a multicolored, speckled, or textured surface, are not valid. 1.3 For solid colored tile, a comparison of the test specimen and reference specimen should be made under incandescent, f...

  15. Thermal energy consumption and carbon dioxide emissions in ceramic tile manufacture - Analysis of the Spanish and Brazilian industries

    International Nuclear Information System (INIS)

    Spain and Brazil are two of the world's biggest ceramic tile producers. The tile manufacturing process consumes a great quantity of thermal energy that, in these two countries, is mainly obtained from natural gas combustion, which entails CO2 emission, a greenhouse gas. This study presents a comparative analysis of the thermal energy consumption and CO2 emissions in the ceramic tile manufacturing process in Spain and Brazil, in terms of the different production technologies and different products made. The energy consumption and CO2 emissions in ceramic tile manufacture by the wet process are very similar in both countries. In the dry process used in Brazil, less thermal energy is consumed and less CO2 is emitted than in the wet process, but it is a process that is only used in manufacturing one particular type of product, which exhibits certain technical limitations. While in Spain the use of cogeneration systems in spray-dryers improves significantly the global energy efficiency. The average energy consumption in the different process stages, in both countries, lies within the range indicated in the Reference Document on Best Available Techniques in the Ceramic Manufacturing Industry (BREF of the Ceramic Manufacturing Industry) of the European Union. (Author) 14 refs.

  16. Decorative design of ceramic tiles adapted to inkjet printing employing digital image processing; Diseno decorativo de pavimentos ceramicos adaptado a inyeccion de tinta mediante tratamiento digital de imagen

    Energy Technology Data Exchange (ETDEWEB)

    Defez, B.; Santiago-Praderas, V.; Lluna, E.; Peris-Fajarnes, G.; Dunai, E.

    2013-09-01

    The ceramic tile sector is a very competitive industry. The designer's proficiency to offer new models of the decorated surface, adapted to the production means, plays a very important role in the competitiveness. In the present work, we analyze the evolution of the design process in the ceramic sector, as much as the changes experimented in parallel by the printing equipment. Afterwards, we present a new concept of ceramic design, based on digital image processing. This technique allows the generation of homogeneous and non-repetitive designs for large surfaces, especially thought for inkjet printing. With the programmed algorithms we have compiled a prototype software for the assistance of the ceramic design. This tool allows creating continuous designs for large surfaces saving developing time. (Author)

  17. Radon exhalation rates corrected for leakage and back diffusion – Evaluation of radon chambers and radon sources with application to ceramic tile

    Directory of Open Access Journals (Sweden)

    M. Abo-Elmagd

    2014-10-01

    Full Text Available The natural radon decay, leakage and back diffusion are the main removal processes of radon from its container. Ignoring these processes leads to underestimate the measured value of radon related parameters like exhalation rate and radium content. This work is aimed to evaluate two different radon chambers through determining their leakage rate λv and evaluation of radon source by determine its back diffusion rate λb inside the evaluated radon chambers as well as a small sealed cup. Two different methods are adapted for measuring both the leakage rate and the back diffusion rate. The leakage rate can be determined from the initial slope of the radon decay curve or from the exponential fitting of the whole decay curve. This can be achieved if a continuous monitoring of radon concentration inside the chamber is available. Also, the back diffusion rate is measured by sealing the radon source in the chamber and used the initial slope of the buildup curve to determine λb and therefore the exhalation rate of the source. This method was compared with simple equation for λb based on the ratio of the source to the chamber volume. The obtained results are applied to ceramic tile as an important radon source in homes. The measurement is targeted the ceramic glaze before and after firing as well as the obtained tile after adhere the glaze on the tile main body. Also, six different tile brands from Egyptian market are subjected to the study for comparison.

  18. Environmental aspects of the production process of ceramic tiles (wet process), with emphasis in liquid effluents

    International Nuclear Information System (INIS)

    Present study developed a simplified methodology to evaluate the environmental impacts of the wet process of production of ceramic tiles. In order to subsidize the development of the model of environmental evaluation and to achieve a better understanding of the productive process, there were elaborated matrices in which was correlated the stages of the productive system with the respective types and volumes of residues generated. To these matrices there were related the technical norms of the Brazilian Association of Norms and Techniques (ABNT), which determines the sampling methodologies, characterizations, monitoring and treatment of the solid residues and liquid and gaseous effluents; and the pertinent Federal and State Legislations which dispose on the control of the environmental pollution. The evaluation of the environmental impact model here proposed was developed fram the Interaction Matrix of Leopold and from the Risk Matrix proposed by Moura, in which identified the pollutant effects (critical, significant, reduced, marginal) of the stages of this productive process. The validation of these results was obtained through the accomplishment of analytic assays in the used raw materials and in the residues generated in the productive process. The results of the chemical analyses reinforce that the positive toxicity in the liquid effluent is related with the chemical composition of the synthetic raw material used in the decoration. It was concluded that the solid residues that more damage cause to the environment are those coming from the enamel and dying preparation and application sections. Concomitantly, it was performed a study of characterization of the natural raw materials and of the product, using different techniques as fluorescence X ray, differential thermal analysis with thermogravimetry, scanning electron microscopy and X ray diffraction, in order to understand the interactions of the components of the mass of the ceramic body, during the stage of

  19. Analysis of energy consumption and carbon dioxide emissions in ceramic tile manufacture; Analisis de consumos energeticos y emisiones de dioxido de carbono en la fabricacion de baldosas ceramicas

    Energy Technology Data Exchange (ETDEWEB)

    Monfort, E.; Mezquita, A.; Granel, R.; Vaquer, E.; Escrig, A.; Miralles, A.; Zaera, V.

    2010-07-01

    The ceramic tile manufacturing process is energy intensive since it contains several stages in which the product is subject to thermal treatment. The thermal energy used in the process is usually obtained by combustion of natural gas, which is a fossil fuel whose oxidation produces emissions of carbon dioxide, a greenhouse gas. Energy costs account for 15% of the average direct manufacturing costs, and are strongly influenced by the price of natural gas, which has increased significantly in the last few years. Carbon dioxide emissions are internationally monitored and controlled in the frame of the Kyoto Protocol. Applicable Spanish law is based on the European Directive on emissions trading, and the assignment of emissions rights is based on historical values in the sectors involved. Legislation is scheduled to change in 2013, and the resulting changes will directly affect the Spanish ceramic tile manufacturing industry, since many facilities will become part of the emissions trading system. The purpose of this study is to determine current thermal energy consumption and carbon dioxide emissions in the ceramic tile manufacturing process. A comprehensive sectoral study has been carried out for this purpose on several levels: the first analyses energy consumption and carbon dioxide emissions in the entire industry; the second determines energy consumption and carbon dioxide emissions in industrial facilities over a long period of time (several months); while the third level breaks down these values, determining energy consumption and emissions in terms of the product made and the manufacturing stage. (Author) 8 refs.

  20. Comparison of slime-producing coagulase-negative Staphylococcus colonization rates on vinyl and ceramic tile flooring materials.

    Science.gov (United States)

    Yazgi, H; Uyanik, M H; Ayyildiz, A

    2009-01-01

    This study investigated the colonization of slime-producing coagulase-negative Staphylococcus (CoNS) in 80 patient wards in Turkey (40 vinyl and 40 ceramic tile floors). A total of 480 samples that included 557 CoNS isolates were obtained. Slime production was investigated with the Christensen method and methicillin-susceptibility was tested by the disk-diffusion method. There was a significant difference in the percentage of slime-producing CoNS isolates on vinyl (12.4%) versus ceramic tile flooring (4.4%). From vinyl flooring, the percentage of slime producing methicillin-resistant CoNS (MRCoNS) (8.9%) was significantly higher than for methicillin-sensitive CoNS (MSCoNS) (3.6%), whereas there was no difference from ceramic tile flooring (2.5% MRCoNS versus 1.8% MSCoNS). The most commonly isolated slime-producing CoNS species was S. epidermidis on both types of flooring. It is concluded that vinyl flooring seems to be a more suitable colonization surface for slime-producing CoNS than ceramic tile floors. Further studies are needed to investigate bacterial strains colonized on flooring materials, which are potential pathogens for nosocomial infections. PMID:19589249

  1. PREPARATION OF RECYCLING CERAMIC TILES USING CERAMIC INDUSTRIAL WASTE%利用陶瓷工业废料制备再生陶瓷墙地砖

    Institute of Scientific and Technical Information of China (English)

    王功勋

    2011-01-01

    Recycling ceramic tile was made from raw materials using waste ceramic polishing powder(PP),and waste tiles,and using borax was added as a supplementary flux.Effects of PP sintering property on the strength of recycling ceramic tiles were investigated.Effects of PP on microstructure were detected by SEM tests.Results show that PP is beneficial to improve the sintering property because of its fine particle and glass phase.Strength of recycling ceramic tiles is increased by adding PP and borax compound.In the experimental,borax mass fraction of 0.5%,PP mass fraction of 2% and ceramic tile granule mass fraction of 25%,the strength of recycling ceramic tiles is the highest.This treatment technology features large integrated utilization efficiency for ceramic industrial waste and high strength of recycle ceramic tiles.%以废弃陶瓷抛光砖粉、陶瓷墙地砖烧成废料为原材料,硼砂作辅助熔剂制备再生陶瓷墙地砖,研究陶瓷抛光砖粉的高温烧结性能及其对再生墙地砖强度的影响,采用SEM测试分析陶瓷抛光砖粉对再生陶瓷制品微观结构的影响。结果表明:抛光砖粉含玻璃相、颗粒细小,有利坯体烧结密实;复掺少量抛光砖粉和硼砂,可提高制品强度。在硼砂掺量为0.5%,陶瓷抛光砖粉为2%、烧成废料为25%的实验条件下,所得再生陶瓷制品强度最高。该方法具有陶瓷工业废料的综合利用率高,制得的再生陶瓷制品强度高等特点。

  2. Investigation by laser induced breakdown spectroscopy, X-ray fluorescence and X-ray powder diffraction of the chemical composition of white clay ceramic tiles from Veliki Preslav

    Energy Technology Data Exchange (ETDEWEB)

    Blagoev, K., E-mail: kblagoev@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Grozeva, M., E-mail: margo@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Malcheva, G., E-mail: bobcheva@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Neykova, S., E-mail: sevdalinaneikova@abv.bg [National Institute of Archaeology with Museum, Bulgarian Academy of Sciences, 2 Saborna, 1000 Sofia (Bulgaria)

    2013-01-01

    The paper presents the results of the application of laser induced breakdown spectroscopy, X-ray fluorescence spectrometry, and X-ray powder diffraction in assessing the chemical and phase composition of white clay decorative ceramic tiles from the medieval archaeological site of Veliki Preslav, a Bulgarian capital in the period 893–972 AC, well-known for its original ceramic production. Numerous white clay ceramic tiles with highly varied decoration, produced for wall decoration of city's churches and palaces, were found during the archaeological excavations in the old capital. The examination of fourteen ceramic tiles discovered in one of the city's monasteries is aimed at characterization of the chemical profile of the white-clay decorative ceramics produced in Veliki Preslav. Combining different methods and comparing the obtained results provides complementary information regarding the white-clay ceramic production in Veliki Preslav and complete chemical characterization of the examined artefacts. - Highlights: ► LIBS, XRF and XRD analyses of medieval white-clay ceramic tiles fragments are done. ► Different elements and phases, presented in the ceramics fragments were determined. ► Differences in the tiles' raw material mineral composition are found. ► Information of the tiles' production process and the raw clay deposits is obtained.

  3. Investigation by laser induced breakdown spectroscopy, X-ray fluorescence and X-ray powder diffraction of the chemical composition of white clay ceramic tiles from Veliki Preslav

    International Nuclear Information System (INIS)

    The paper presents the results of the application of laser induced breakdown spectroscopy, X-ray fluorescence spectrometry, and X-ray powder diffraction in assessing the chemical and phase composition of white clay decorative ceramic tiles from the medieval archaeological site of Veliki Preslav, a Bulgarian capital in the period 893–972 AC, well-known for its original ceramic production. Numerous white clay ceramic tiles with highly varied decoration, produced for wall decoration of city's churches and palaces, were found during the archaeological excavations in the old capital. The examination of fourteen ceramic tiles discovered in one of the city's monasteries is aimed at characterization of the chemical profile of the white-clay decorative ceramics produced in Veliki Preslav. Combining different methods and comparing the obtained results provides complementary information regarding the white-clay ceramic production in Veliki Preslav and complete chemical characterization of the examined artefacts. - Highlights: ► LIBS, XRF and XRD analyses of medieval white-clay ceramic tiles fragments are done. ► Different elements and phases, presented in the ceramics fragments were determined. ► Differences in the tiles' raw material mineral composition are found. ► Information of the tiles' production process and the raw clay deposits is obtained

  4. How does the innovation system in the Spanish ceramic tile sector function?

    OpenAIRE

    Gabaldón Estevan, Daniel; Hekkert, M.P.

    2013-01-01

    [EN]: In this article we apply the functions of innovation systems framework to assess its appropriateness to characterise the innovation activity of the tile industry in Castellón. This framework is based on idea that a well functioning innovation system requires that a number of key activities take place. If this occurs innovative output is higher. Our analysis provides a deeper understanding of the role of innovation as a strategic option in a mature industry in the context of globalisatio...

  5. How Does the Innovation System in the Spanish Ceramic Tile Sector Function?

    Energy Technology Data Exchange (ETDEWEB)

    Gabaldon-Estevan, D.; Hekkert, M. P.

    2013-06-01

    In this article we apply the functions of innovation systems framework to assess its appropriateness to characterise the innovation activity of the tile industry in Castellon. This framework is based on idea that a well functioning innovation system requires that a number of key activities take place. If this occurs innovative output is higher. Our analysis provides a deeper understanding of the role of innovation as a strategic option in a mature industry in the context of globalisation. By applying this new theoretical approach to study innovation and highlighting the functions that the system requires, we shown the constraints, inertias, challenges and opportunities that the innovation system of the tile industry in Castellon faces. The results also show that the functional approach allows higher flexibility in order to recognise and analyse the opportunities and constraints that a given innovation system presents. (Author) 20 refs.

  6. Barium zirconate base ceramics

    International Nuclear Information System (INIS)

    The chemical corrosion at high temperatures is a serious problem in the refractory materials field, leading to degradation and bath contamination by elements of the refractory. The main objective of this work was to search for ceramics that could present higher resistance to chemical attack by aggressive molten oxides. The general behaviour of a ceramic material based on barium zirconate (Ba Zr O3) with the addition of different amounts of liquid phase former was investigated. The densification behaviour occurred during different heat treatments, as well as the microstructure development, as a function of the additives and their reactions with the main phase, were observed and are discussed. (author)

  7. Beautiful math, part 2: aesthetic patterns based on fractal tilings.

    Science.gov (United States)

    Peichang Ouyang; Fathauer, Robert W

    2014-01-01

    A fractal tiling (f-tiling) is a tiling whose boundary is fractal. This article presents two families of rare, infinitely many f-tilings. Each f-tiling is constructed by reducing tiles by a fixed scaling factor, using a single prototile, which is a segment of a regular polygon. The authors designed invariant mappings to automatically produce appealing seamless, colored patterns from such tilings. PMID:24808170

  8. Compressive Strength and Water Absorption of Pervious Concrete that Using the Fragments of Ceramics and Roof Tiles

    Science.gov (United States)

    Prahara, E.; Meilani

    2014-03-01

    Pervious concrete was introduced in America in 2003, popularized by Dan Brown and used as a rigid pavement in the open parking lot. Rigid pavement using pervious concrete can absorb water in the surface to go straight through the concrete to the ground below.This water flow is one of the benefit of using the pervious concrete. Using of wastes such as broken roof and ceramics tiles are not commonly used in Indonesia. Utilization these kind of wastes is predicted lower the compressive strength of pervious concrete as they are used as a substitute for coarse aggregate.In this research, pervious concrete is made using a mixture of the fragment of ceramics and roof tiles.This research using broken ceramics and roof tiles with a grain size that loose from 38 mm sieve, retained on 19 mm sieve and the coarse aggregate from crushed stone that loose 12.5 mm sieve, retained on 9.5 mm sieve. The water cement ratio is 0.3 and to assist the mixing process, the addition of addictive in pervious concrete is used.The size of coarse aggregate used in the mixture affects the strength of pervious concrete. The larger the size of aggregate, the obtained compressive strength becomes smaller. It also affects the density of pervious concrete. The using of mixture of ceramics and roof tiles only reduce 2 MPa of pervious concrete compressive strength so this mixture can be used as a substitute for coarse aggregate with a maximum portion of 30 %. The high porosity of the specimens causes the reduction of pervious concrete density that affect the compressive strength. This high level of porosity can be seen from the high level of water absorption that exceed the required limit of water infiltration.

  9. Compressive Strength and Water Absorption of Pervious Concrete that Using the Fragments of Ceramics and Roof Tiles

    Directory of Open Access Journals (Sweden)

    Prahara E.

    2014-03-01

    Full Text Available Pervious concrete was introduced in America in 2003, popularized by Dan Brown and used as a rigid pavement in the open parking lot. Rigid pavement using pervious concrete can absorb water in the surface to go straight through the concrete to the ground below.This water flow is one of the benefit of using the pervious concrete. Using of wastes such as broken roof and ceramics tiles are not commonly used in Indonesia. Utilization these kind of wastes is predicted lower the compressive strength of pervious concrete as they are used as a substitute for coarse aggregate.In this research, pervious concrete is made using a mixture of the fragment of ceramics and roof tiles.This research using broken ceramics and roof tiles with a grain size that loose from 38 mm sieve, retained on 19 mm sieve and the coarse aggregate from crushed stone that loose 12.5 mm sieve, retained on 9.5 mm sieve. The water cement ratio is 0.3 and to assist the mixing process, the addition of addictive in pervious concrete is used.The size of coarse aggregate used in the mixture affects the strength of pervious concrete. The larger the size of aggregate, the obtained compressive strength becomes smaller. It also affects the density of pervious concrete. The using of mixture of ceramics and roof tiles only reduce 2 MPa of pervious concrete compressive strength so this mixture can be used as a substitute for coarse aggregate with a maximum portion of 30 %. The high porosity of the specimens causes the reduction of pervious concrete density that affect the compressive strength. This high level of porosity can be seen from the high level of water absorption that exceed the required limit of water infiltration.

  10. Hardware Algorithms For Tile-Based Real-Time Rendering

    NARCIS (Netherlands)

    Crisu, D.

    2012-01-01

    In this dissertation, we present the GRAphics AcceLerator (GRAAL) framework for developing embedded tile-based rasterization hardware for mobile devices, meant to accelerate real-time 3-D graphics (OpenGL compliant) applications. The goal of the framework is a low-cost, low-power, high-performance d

  11. Comparative study of ceramic tiles produced in the Town of Goytacazes / RJ (Brazil); Estudo comparativo de telhas ceramicas produzidas no municipio de Campos dos Goytacazes, RJ

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, L.L.P. de; Pacheco, A.T.; Carreiro, R.S; Petrucci, L.J.T., E-mail: lezira@ig.com.br [Fundacao de Apoio a Escola Tecnica (FAETEC), Campos dos Goytacazes, RJ (Brazil). Centro Vocacional Tecnologico - Ceramica

    2011-07-01

    The city of the Campos dos Goytacazes, situated in the region north of the state of Rio de Janeiro, presents characteristics place that it enter the producing greater of blocks and ceramic roofing tiles for the domestic market. This work makes a study enters four manufacturers of ceramic roofing tiles of the city of the Campos dos Goytacazes/RJ, to analysis comparatively its results according to in agreement the characterization submitted to dilatometry, Thermogravimetry, Differential Thermal Analysis and X-ray diffraction for the physical tests the tiles were collected after burning and the tests under Bylaw NBR 15310. The results had indicated a significant variation in the values of water absorption of each manufacturer. The same ones demonstrate that the ceramic roofing tiles of Campos of the Goytacazes present a uniformity in the results, being that it needs technological accompaniment during the manufacture process, to improve its properties and its quality for adequacy to the normative parameters of the ABNT. (author)

  12. Program-technical complex for sorting ceramic tiles with the method of artificial intellect

    Science.gov (United States)

    Aliyev, Namik; Aliyev, Elchin

    2001-08-01

    Development of areas of automated systems of management of technological processes and systems of local automation requires the resolving of a set of questions on identification of production operations, working out industrial methods of measuring and control. Program-technical complex containing the systems of artificial vision, integrating device and dynamic expert systems of ready-product quality control in the example of decorative tile are examined at this work. The problem of identification of image can not be fully formalized and solved with the usage of strict algorithmic procedures and mathematical methods. Due to the mentioned fact, the development of intellectual programming methods- expert systems of image identification should provide effectiveness of mathematical methods of processing and heuristic programming with the expert knowledge of characteristics in analyzed systems. Implementation of the proposed complex, spares the specialist from routine job, allows timely spotting of technological process, solves the problem of sorting of ceramic materials in real time frame. In the meantime, the implementation of the system in dialog mode gives suggestions and recommendations.

  13. Preparation and characterization of novel glass–ceramic tile with microwave absorption properties from iron ore tailings

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Rui; Liao, SongYi [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Dai, ChangLu [Guangdong Bode Fine Building Material Co. Ltd., Foshan 528000 (China); Liu, YuChen; Chen, XiaoYu [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Zheng, Feng, E-mail: fzheng@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Phase diagrams and materials design center, Central South University, Changsha 410083 (China)

    2015-03-15

    A novel glass–ceramic tile consisting of one glass–ceramic layer (GC) attaining microwave absorption properties atop ceramic substrate was prepared through quench-heat treatment route derived from iron ore tailings (IOTs) and commercial raw materials (purity range 73–99%). X-ray diffraction (XRD), SEM, Energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), Physical property measurement system (PPMS) and Vector network analyzer (VNA) measurements were carried out to investigate phase, microstructure, magnetic and microwave absorption aspects of the glass–ceramic layer. Roughly 80.6±1.7 wt% borosilicate glass and 19.4±1.7 wt% spinel ferrite with chemical formula of (Zn{sup 2+}{sub 0.17}Fe{sup 3+}{sub 0.83})[Fe{sup 3+}{sub 1.17}Fe{sup 2+}{sub 0.06}Ni{sup 2+}{sub 0.77}]O{sub 4} were found among the tested samples. Absorption of Electromagnetic wave by 3 mm thick glass–ceramic layer at frequency of 2–18 GHz reached peak reflection loss (RL) of −17.61 dB (98.27% microwave absorption) at 10.31 GHz. Altering the thickness of the glass–ceramic layer can meet the requirements of different level of microwave absorption. - Highlights: • Iron ore tailings (IOTs) have been used as one of the main raw materials. • Glass–ceramic tile contains spinel ferrite has been prepared. • The cation distribution of the spinel ferrite has been calculated. • The intrinsic complex permeability and permittivity have been evaluated.

  14. Preparation and characterization of novel glass–ceramic tile with microwave absorption properties from iron ore tailings

    International Nuclear Information System (INIS)

    A novel glass–ceramic tile consisting of one glass–ceramic layer (GC) attaining microwave absorption properties atop ceramic substrate was prepared through quench-heat treatment route derived from iron ore tailings (IOTs) and commercial raw materials (purity range 73–99%). X-ray diffraction (XRD), SEM, Energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), Physical property measurement system (PPMS) and Vector network analyzer (VNA) measurements were carried out to investigate phase, microstructure, magnetic and microwave absorption aspects of the glass–ceramic layer. Roughly 80.6±1.7 wt% borosilicate glass and 19.4±1.7 wt% spinel ferrite with chemical formula of (Zn2+0.17Fe3+0.83)[Fe3+1.17Fe2+0.06Ni2+0.77]O4 were found among the tested samples. Absorption of Electromagnetic wave by 3 mm thick glass–ceramic layer at frequency of 2–18 GHz reached peak reflection loss (RL) of −17.61 dB (98.27% microwave absorption) at 10.31 GHz. Altering the thickness of the glass–ceramic layer can meet the requirements of different level of microwave absorption. - Highlights: • Iron ore tailings (IOTs) have been used as one of the main raw materials. • Glass–ceramic tile contains spinel ferrite has been prepared. • The cation distribution of the spinel ferrite has been calculated. • The intrinsic complex permeability and permittivity have been evaluated

  15. Analysis and Monitoring Results of a Building Integrated Photovoltaic Façade Using PV Ceramic Tiles in Taiwan

    Directory of Open Access Journals (Sweden)

    Yen-Chieh Huang

    2014-01-01

    Full Text Available Single-crystal silicon-based solar cells laminated with tempered-glass and ceramic tiles for use in a building’s façade have been developed. The optical, thermal, and electrical properties of the proposed PV module are first evaluated, and then a wind-resistance test is carried out to evaluate the feasibility of installing it in Taiwan. The electrical and deflection characteristics of the proposed PV module did not change significantly after a 50 thermal cycling test and a 200-hour humidity-freeze test, based on IEC 61215 and a wind-resistance test. Finally, the electrical power generation ability of the proposed BIPV system with 1 kWp electrical power capacity was examined. Building information modeling software tools were used to simulate the BIPV system and carry out the energy analysis. The simulation results show a very consistent trend with regard to the actual monthly electricity production of the BIPV system designed in this work. The BIPV system was able to produce an accumulative electrical power of 185 kWh during the 6-month experimental period. In addition, the exterior temperature of the demonstration house was about 10°C lower than the surface of the BIPV system, which could reduce indoor temperature.

  16. Solar Photocatalytic Removal of Chemical and Bacterial Pollutants from Water Using Pt/TiO2-Coated Ceramic Tiles

    Directory of Open Access Journals (Sweden)

    S. P. Devipriya

    2012-01-01

    Full Text Available Semiconductor photocatalysis has become an increasingly promising technology in environmental wastewater treatment. The present work reports a simple technique for the preparation of platinum-deposited TiO2 catalysts and its immobilization on ordinary ceramic tiles. The Pt/TiO2 is characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDAX, and diffuse reflectance spectroscopy (DRS. Deposition of Pt on TiO2 extends the optical absorption of the latter to the visible region which makes it attractive for solar energy application. Optimum loading of Pt on TiO2 was found to be 0.5%. The Pt/TiO2 is coated on ceramic tiles and immobilized. This catalyst was found effective for the solar photocatalytic removal of chemical and bacterial pollutants from water. Once the parameters are optimized, the Pt/TiO2/tile can find application in swimming pools, hospitals, water theme parks, and even industries for the decontamination of water.

  17. Thermo Physical Characteristics of Vitrified Tile Polishing Waste for Use in Traditional Ceramics-An Initiative of Cgcri, Naroda Centre

    Science.gov (United States)

    Misra, S. N.; Machhoya, B. B.; Savsani, R. M.

    This paper reports the thermo physical characteristics of Vitrified tile polishing waste materials. As such growing production of vitrified tiles in the country generate large volume of this waste obtained during processing, polishing and cutting of the vitrified tiles to the tune of nearly 10-15 tonnes per day from each plant. The characteristic features of these materials are being studied and investigated to develop suitable technology for finding its gainful use especially in the traditional ceramics. It is known that ceramic as such building materials industry could be a large raw materials consumer and being heterogeneous and thus could utilize this vast quantity as the raw materials. However, the main problem would be it's firing nature as it showed thermal deformation after a particular temperature. Interestingly, the production process of most of the traditional ceramics follows a similar pattern starting from the raw materials processing up to a level of firing. Hence, to suggest suitable utility in the traditional ceramics as raw materials, it was the prime requisite that these waste must be thoroughly studied w. r. t various thermo physical characteristics to make use in this sectors. Hence, the present paper interestingly gone up to various study such as raw materials nature, particle size distribution, chemistry, XRD and DTA study for understanding typical physico chemical properties, and finally thermal properties to make it suitable for use in traditional ceramic industries. The higher fineness of the waste materials indicates its usefulness without extra grinding. The chemistry of typical sludge shows contamination from abrasive particles, sorrel cement bonding materials etc. originated from the polishing wheel and needs special precaution while suggesting use in the ceramic sectors. The firing characteristics of the sludge materials produces a foamy and spongy shapes and this could be the main guiding parameters in selecting the end use of the

  18. Analysis on the Fluoride from the Ceramic Tile Production Process%瓷砖生产过程中氟化物分析

    Institute of Scientific and Technical Information of China (English)

    黄豫; 杨爱江; 吕剑明; 王素娟; 张俊

    2012-01-01

    对瓷砖生产过程中坯料、釉料、煤及煤气中氟化物进行分析,研究氟化物的来源、迁移和转化.研究结果表明,坯料、釉料和煤是氟化物来源,且三者氟化物所占分别为46%、48%和6%.氟化物的输出30.2%固定于成品瓷砖,69.6%经尾气烟囱排放.%Based on the analysis of fluoride amount of ceramic tile blank, glaze materials, coal and gas fluoride in the process of production, the study gives the research on the source of fluoride and its migration and transformation. The results show that fluoride sources are blank (46% ), glaze materials (48% ) and coal (6% ) and 30.2% of the output fluoride fixed in ceramic tile, 69.6% released out of chimney along with the exhaust emissions.

  19. Compressive Strength and Water Absorption of Pervious Concrete that Using the Fragments of Ceramics and Roof Tiles

    OpenAIRE

    Prahara E.; Meilani

    2014-01-01

    Pervious concrete was introduced in America in 2003, popularized by Dan Brown and used as a rigid pavement in the open parking lot. Rigid pavement using pervious concrete can absorb water in the surface to go straight through the concrete to the ground below.This water flow is one of the benefit of using the pervious concrete. Using of wastes such as broken roof and ceramics tiles are not commonly used in Indonesia. Utilization these kind of wastes is predicted lower the compressive strength ...

  20. Moisture expansion of ceramic tiles produced using kaolin and granite wastes; Expansao por umidade de revestimentos ceramicos incorporados com residuos de granito e caulim

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca, A.M.G.D.; Cartaxo, J.M.; Santana, L.N.L; Neves, G.A.; Ferreira, H.C., E-mail: ana.duartemendonca@gmail.com, E-mail: gelmires@dema.ufcg.edu.br, E-mail: lisiane@dema.ufcg.edu.br [Unidade Academica de Engenharia de Materiais, Universidade Federal de Campina Grande,Campina Grande, PB (Brazil); Menezes, R.R. [Departamento de Engenharia de Materiais, Universidade Federal da Paraiba, Joao Pessoa, PB (Brazil)

    2012-04-15

    Moisture expansion (ME) is the term used to describe the expansion of ceramic materials due to the adsorption of water. ME usually occurs slowly and is relatively small, but, it can damage the ceramic tiles adhesion to the underlayment, craze the glaze and lead to the development of cracks on ceramics bricks. In this work kaolin and granite wastes were incorporated in ceramic compositions aiming study their influence on the ME of ceramic tiles. Raw materials were processed and submitted to characterization: physical and mineralogical by laser diffraction particle size analysis, chemical analysis, thermo differential and thermogravimetric analysis and X-ray diffraction. Results showed that kaolin and granite wastes can be incorporated in ceramic composition because display characteristics similar to conventional not plastic ceramic materials, providing satisfactory ME results when compared to the ME limit value of 0.6 mm/m (0.06%) indicated by the ABNT for ceramic tiles. Compositions containing up to 20% of waste can be produced when firing above 1000 deg C. (author)

  1. Modeling and simulation of the atomization process in the ceramic tile industry

    International Nuclear Information System (INIS)

    The aim of the present work is to numerically simulate the behaviour of the drying system for several sets of operating conditions in order to improve and optimize this process. However, the mathematical modeling adopted here can be employed to simulate other systems such as the processes that occur in liquid-fueled engines with direct spray injection and ceramic spraying for hard surfacing. Then, mathematical and physical models were established to simulate the interaction of continuous and disperse phases in drying processes of ceramic slurries. Solving the set of governing coupled partial differential equations, it is possible to study the influence of drying air on the atomized droplets of alumina slurry, and vice-versa. The materials used as continuous and disperse phase, air and alumina slurry respectively, are representative since any kind of gas and slurry can be used if its thermodynamic and transport properties are known. Several experimental tests were carried out in a spray dryer in the 'Laboratorio de Insumos', at IPEN - Instituto de Pesquisas Energeticas e Nucleares for different sets of operating conditions: initial temperature of the drying air, the gas flow rate, the slurry feed rate and atomiser configuration among others. Measurements of the wet and the dry bulb temperatures were made in some experimental tests to allow the calculations of the air humidity. The dynamic pressure were also measured in order to determine the gas flow rate. Some samples of the material used in the tile industry and of the one produced at IPEN were analysed to determine: the morphology of the atomized material and the range of granules diameter through scanning electron microscopy; the amount of pores and the bulk density through porosimetry; the residual moisture of the material through thermogravimetry; and the granulometric distribution of granules and particles through laser diffraction. Important information about the process and the final material are given by

  2. Influence of gypsum on efflorescence in ceramic tiles; Influence da gipsita no surgimento de eflorescencia em telhas ceramicas

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, C.M.O.L. [Servico Nacional de Aprendizagem Industrial (SENAI), Teresina, PI (Brazil); Nascimento, R.M.; Martinelli, A.E. [Universidade Federal do Rio Grande do Norte (PPgCEM/UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

    2009-07-01

    The red ceramic industry is recognized as of major importance in Piaui State. The State capital, Teresina, is the greatest producer of this material, which is used mainly for masonry sealing blocks. One of the most frequent problems in this kind of products is the efflorescence.This paper has the main objective of studying the influence of gypsum on tiles, using the local industry production standards. The raw materials were characterized by FRX, DRX, thermal analysis and sulfates. Extruded test specimens were made with the addition of 1%, 3% and 5% of gypsum in the ceramic paste, burned at 850 deg C, 950 deg C and 1050 deg C and submitted to further technological and analysis for MEV. The reference ceramic paste did not show tendency to efflorescence formation after burning for samples with 1% gypsum added to the paste. The reference ceramic paste showed tendency to efflorescence formation after drying and consolidated efflorescence after burning for samples with 5% gypsum added to the paste. (author)

  3. Integrator based read-out in Tile Calorimeter of the ATLAS experiment

    CERN Document Server

    Gonzalez, G; The ATLAS collaboration

    2011-01-01

    TileCal, the central hadronic calorimeter of the ATLAS experiment at the CERN Large Hadron Collider (LHC), is built of steel and scintillating tiles with redundant readout by optical fibers and uses photomultipliers as photodetectors. It provides measurements for hadrons, jets and missing transverse energy. To equalize the response of individual TileCal cells with a precision better than 1% and to monitor the response of each cell over time, a calibration and monitoring system based on a Cesium 137 radioactive source driven through the calorimeter volume by liquid flow has been implemented. This calibration system relies on dedicated readout chain based on slow integrators that read currents from the TileCal photomultipliers averaged over milliseconds during the calibration runs. During the LHC collisions the TileCal integrator based readout provides monitoring of the beam conditions and of the stability of the TileCal optics, including stability of the photomultiplier gains. The work to be presented will foc...

  4. Environmental development of the Spanish ceramic tile manufacturing sector over the period 1992–2007

    OpenAIRE

    Celades López, Irina; Moliner Salvador, R.; Ros-Dosdá, Teresa; Monfort Gimeno, Eliseo; Zaera, Eulalio

    2012-01-01

    The Spanish tile manufacturing sector has grown steadily over the years covered by the three benchmark studies, carried out in 1992, 2001, and 2007, from which data are compared in this paper. In that period, production output doubled, although since the last study was published, the situation has undergone a radical change and current production output stands at a level similar to that of 1995. Nevertheless, despite the world economic crisis, which has also severely impacted the ...

  5. Application of sewage sludge in the manufacturing of ceramic tile bodies

    OpenAIRE

    Jordán, Manuel; Almendro, M. B.; Rincón López, Jesús María; Romero, Maximina

    2005-01-01

    The substitution of clayey raw materials urban sewage sludge in the production of traditional ceramics could give place to a cost saving due to the utilisation of wastes as secondary raw material. At the same time, it can help to solve the environmental problems associated to such wastes. This research shows the results of the substitution of clay for sewage sludge in different proportions in a ceramic body. The sludge characterisation has been carried out by an analytical protocol. After tha...

  6. 自动液压压砖机液压油的选用%The Selection of Hydraulic Oil of Automatic Hydraulic Press for Ceramic Tiles

    Institute of Scientific and Technical Information of China (English)

    任小平; 汪建晓

    2001-01-01

    The types and characteristics of hydraulic oil are briefly introduced, and the selection methods of hydraulic oil of automatic hydraulic ress for ceramic tiles are presented.%本文简要介绍了液压油的类型和性能指标,阐述了全自动液压压砖机液压油的选用方法。

  7. Thermodynamics and Kinetics of DNA Tile-Based Self-Assembly

    Science.gov (United States)

    Jiang, Shuoxing

    Deoxyribonucleic acid (DNA) has emerged as an attractive building material for creating complex architectures at the nanometer scale that simultaneously affords versatility and modularity. Particularly, the programmability of DNA enables the assembly of basic building units into increasingly complex, arbitrary shapes or patterns. With the expanding complexity and functionality of DNA toolboxes, a quantitative understanding of DNA self-assembly in terms of thermodynamics and kinetics, will provide researchers with more subtle design guidelines that facilitate more precise spatial and temporal control. This dissertation focuses on studying the physicochemical properties of DNA tile-based self-assembly process by recapitulating representative scenarios and intermediate states with unique assembly pathways. First, DNA double-helical tiles with increasing flexibility were designed to investigate the dimerization kinetics. The higher dimerization rates of more rigid tiles result from the opposing effects of higher activation energies and higher pre-exponential factors from the Arrhenius equation, where the pre-exponential factor dominates. Next, the thermodynamics and kinetics of single tile attachment to preformed "multitile" arrays were investigated to test the fundamental assumptions of tile assembly models. The results offer experimental evidences that double crossover tile attachment is determined by the electrostatic environment and the steric hindrance at the binding site. Finally, the assembly of double crossover tiles within a rhombic DNA origami frame was employed as the model system to investigate the competition between unseeded, facet and seeded nucleation. The results revealed that preference of nucleation types can be tuned by controlling the rate-limiting nucleation step. The works presented in this dissertation will be helpful for refining the DNA tile assembly model for future designs and simulations. Moreover, The works presented here could also be

  8. Analysis of the impact of ISO 14001 in the economic variables of the Spanish ceramic tile industry's companies

    International Nuclear Information System (INIS)

    The increased in the adoption of formally environmental certified practices through environmental management systems is a provable fact. Its implementation, which has a high cost for the companies, is expected to generate benefits, although the relation between the implementation of ISO 14001 and its influence on the improvement of economic indicators over time has not been documented. This paper analyzes the relation between the implementation of an environmental management system, the ISO 14001, and economic performance in the short, medium and long term for the companies of the Spanish ceramic tile industry. It explores the economic indicators for each of the 66 manufacturing companies which have implemented the aforementioned standard from 1996 until 2009 through a comparison with a control group. Results show that ISO 14001 does not affect the economic results of the studied companies. We have not found significant differences in the operating income values, neither in the increase in revenues in the long term in any of the three analyzed periods, contrary to the expected results. (Author) 60 refs.

  9. Back relief geometry of ceramic tiles: historic evolution, current considerations and new design approaches.; Geometria al dorso de baldosa ceramica: evolucion historica, consideraciones actuales y nuevos enfoques de diseno

    Energy Technology Data Exchange (ETDEWEB)

    Defez, B.; Peris-Fajarnes, G.; Santiago, V. M.; Brusola simo, F.

    2010-07-01

    Abstract Bibliography related to the design of ceramic floorings, their historic progression and current background is extensive. The investment in the research of new materials formulations, both for ceramic supports, glazes and dyes has been intensive in the last decades, in order to maximize industrial productivity. Nevertheless, there are very few works engaged with the peculiarities of the geometric and structural configuration of ceramic products, where the back relief of the tile could have an essential role. In this article, we report the development of back relief's along time, according to the technological determinants of the sector. Then, we analyze the current situation of ceramic back relief's, as well as their development opportunities with regard to new design factors, namely, the new sales market, the new environmental requirements, and the accomplishment of the international regulations in the matter of quality production and building safety. Finally, we report the new approaches undertaken in the ceramic cluster of Castellon (Spain), with the collaboration of the Universidad Politecnica de Valencia, based on computer aided design. (Author)

  10. Alumina-based ceramic composite

    Science.gov (United States)

    Alexander, Kathleen B.; Tiegs, Terry N.; Becher, Paul F.; Waters, Shirley B.

    1996-01-01

    An improved ceramic composite comprising oxide ceramic particulates, nonoxide ceramic particulates selected from the group consisting of carbides, borides, nitrides of silicon and transition metals and mixtures thereof, and a ductile binder selected from the group consisting of metallic, intermetallic alloys and mixtures thereof is described. The ceramic composite is made by blending powders of the ceramic particulates and the ductile to form a mixture and consolidating the mixture of under conditions of temperature and pressure sufficient to produce a densified ceramic composite.

  11. Tile-Based Two-Dimensional Phase Unwrapping for Digital Holography Using a Modular Framework.

    Science.gov (United States)

    Antonopoulos, Georgios C; Steltner, Benjamin; Heisterkamp, Alexander; Ripken, Tammo; Meyer, Heiko

    2015-01-01

    A variety of physical and biomedical imaging techniques, such as digital holography, interferometric synthetic aperture radar (InSAR), or magnetic resonance imaging (MRI) enable measurement of the phase of a physical quantity additionally to its amplitude. However, the phase can commonly only be measured modulo 2π, as a so called wrapped phase map. Phase unwrapping is the process of obtaining the underlying physical phase map from the wrapped phase. Tile-based phase unwrapping algorithms operate by first tessellating the phase map, then unwrapping individual tiles, and finally merging them to a continuous phase map. They can be implemented computationally efficiently and are robust to noise. However, they are prone to failure in the presence of phase residues or erroneous unwraps of single tiles. We tried to overcome these shortcomings by creating novel tile unwrapping and merging algorithms as well as creating a framework that allows to combine them in modular fashion. To increase the robustness of the tile unwrapping step, we implemented a model-based algorithm that makes efficient use of linear algebra to unwrap individual tiles. Furthermore, we adapted an established pixel-based unwrapping algorithm to create a quality guided tile merger. These original algorithms as well as previously existing ones were implemented in a modular phase unwrapping C++ framework. By examining different combinations of unwrapping and merging algorithms we compared our method to existing approaches. We could show that the appropriate choice of unwrapping and merging algorithms can significantly improve the unwrapped result in the presence of phase residues and noise. Beyond that, our modular framework allows for efficient design and test of new tile-based phase unwrapping algorithms. The software developed in this study is freely available. PMID:26599984

  12. Tile-Based Two-Dimensional Phase Unwrapping for Digital Holography Using a Modular Framework.

    Directory of Open Access Journals (Sweden)

    Georgios C Antonopoulos

    Full Text Available A variety of physical and biomedical imaging techniques, such as digital holography, interferometric synthetic aperture radar (InSAR, or magnetic resonance imaging (MRI enable measurement of the phase of a physical quantity additionally to its amplitude. However, the phase can commonly only be measured modulo 2π, as a so called wrapped phase map. Phase unwrapping is the process of obtaining the underlying physical phase map from the wrapped phase. Tile-based phase unwrapping algorithms operate by first tessellating the phase map, then unwrapping individual tiles, and finally merging them to a continuous phase map. They can be implemented computationally efficiently and are robust to noise. However, they are prone to failure in the presence of phase residues or erroneous unwraps of single tiles. We tried to overcome these shortcomings by creating novel tile unwrapping and merging algorithms as well as creating a framework that allows to combine them in modular fashion. To increase the robustness of the tile unwrapping step, we implemented a model-based algorithm that makes efficient use of linear algebra to unwrap individual tiles. Furthermore, we adapted an established pixel-based unwrapping algorithm to create a quality guided tile merger. These original algorithms as well as previously existing ones were implemented in a modular phase unwrapping C++ framework. By examining different combinations of unwrapping and merging algorithms we compared our method to existing approaches. We could show that the appropriate choice of unwrapping and merging algorithms can significantly improve the unwrapped result in the presence of phase residues and noise. Beyond that, our modular framework allows for efficient design and test of new tile-based phase unwrapping algorithms. The software developed in this study is freely available.

  13. Emerging Ceramic-based Materials for Dentistry

    OpenAIRE

    Denry, I.; Kelly, J. R.

    2014-01-01

    Our goal is to give an overview of a selection of emerging ceramics and issues for dental or biomedical applications, with emphasis on specific challenges associated with full-contour zirconia ceramics, and a brief synopsis on new machinable glass-ceramics and ceramic-based interpenetrating phase composites. Selected fabrication techniques relevant to dental or biomedical applications such as microwave sintering, spark plasma sintering, and additive manufacturing are also reviewed. Where appr...

  14. Emerging Ceramic-based Materials for Dentistry

    Science.gov (United States)

    Denry, I.; Kelly, J.R.

    2014-01-01

    Our goal is to give an overview of a selection of emerging ceramics and issues for dental or biomedical applications, with emphasis on specific challenges associated with full-contour zirconia ceramics, and a brief synopsis on new machinable glass-ceramics and ceramic-based interpenetrating phase composites. Selected fabrication techniques relevant to dental or biomedical applications such as microwave sintering, spark plasma sintering, and additive manufacturing are also reviewed. Where appropriate, the authors have added their opinions and guidance. PMID:25274751

  15. Wang Tiles in Computer Graphics

    CERN Document Server

    Lagae, Ares

    2009-01-01

    Many complex signals in computer graphics, such as point distributions and textures, cannot be efficiently synthesized and stored. This book presents tile-based methods based on Wang tiles and corner tiles to solve both these problems. Instead of synthesizing a complex signal when needed, the signal is synthesized beforehand over a small set of Wang tiles or corner tiles. Arbitrary large amounts of that signal can then efficiently be generated when needed by generating a stochastic tiling, and storing only a small set of tiles reduces storage requirements. A tile-based method for generating a

  16. Tile-based parallel coordinates and its application in financial visualization

    Science.gov (United States)

    Alsakran, Jamal; Zhao, Ye; Zhao, Xinlei

    2010-01-01

    Parallel coordinates technique has been widely used in information visualization applications and it has achieved great success in visualizing multivariate data and perceiving their trends. Nevertheless, visual clutter usually weakens or even diminishes its ability when the data size increases. In this paper, we first propose a tile-based parallel coordinates, where the plotting area is divided into rectangular tiles. Each tile stores an intersection density that counts the total number of polylines intersecting with that tile. Consequently, the intersection density is mapped to optical attributes, such as color and opacity, by interactive transfer functions. The method visualizes the polylines efficiently and informatively in accordance with the density distribution, and thus, reduces visual cluttering and promotes knowledge discovery. The interactivity of our method allows the user to instantaneously manipulate the tiles distribution and the transfer functions. Specifically, the classic parallel coordinates rendering is a special case of our method when each tile represents only one pixel. A case study on a real world data set, U.S. stock mutual fund data of year 2006, is presented to show the capability of our method in visually analyzing financial data. The presented visual analysis is conducted by an expert in the domain of finance. Our method gains the support from professionals in the finance field, they embrace it as a potential investment analysis tool for mutual fund managers, financial planners, and investors.

  17. Multiple lattice tiles and Riesz bases of exponentials

    OpenAIRE

    Kolountzakis, Mihail N.

    2013-01-01

    Suppose $\\Omega\\subseteq\\RR^d$ is a bounded and measurable set and $\\Lambda \\subseteq \\RR^d$ is a lattice. Suppose also that $\\Omega$ tiles multiply, at level $k$, when translated at the locations $\\Lambda$. This means that the $\\Lambda$-translates of $\\Omega$ cover almost every point of $\\RR^d$ exactly $k$ times. We show here that there is a set of exponentials $\\exp(2\\pi i t\\cdot x)$, $t\\in T$, where $T$ is some countable subset of $\\RR^d$, which forms a Riesz basis of $L^2(\\Omega)$. This r...

  18. How Does the Innovation System in the Spanish Ceramic Tile Sector Function?

    OpenAIRE

    Gabaldón Estevan, Daniel; Hekkert, M.P.

    2013-01-01

    The industrial district of Castellon is characterized by a great dynamism based on technological innovation, both product and process, the origins of which are to be found on its providers (1), the machinery industry and the frit, glaze and colours industry. In this paper the current situation of the frit, glaze and colour industry is analyzed, accounting also for the situation of its main European competitor in Italy. The formation and development of the industry is also described in relatio...

  19. Effect of Workplace Noise on Hearing Ability in Tile and Ceramic Industry Workers in Iran: A 2-Year Follow-Up Study

    Directory of Open Access Journals (Sweden)

    Mehrdad Mostaghaci

    2013-01-01

    Full Text Available Introduction. Noise as a common physical hazard may lead to noise-induced hearing loss, an irreversible but preventable disorder. Annual audiometric evaluations help detect changes in hearing status before clinically significant hearing loss develops. This study was designed to track hearing threshold changes during 2-year follow-up among tile and ceramic workers. Methods. This follow-up study was conducted on 555 workers (totally 1110 ears. Subjects were divided into four groups according to the level of noise exposure. Hearing threshold in conventional audiometric frequencies was measured and standard threshold shift was calculated for each ear. Results. Hearing threshold was increased during 2 years of follow-up. Increased hearing threshold was most frequently observed at 4000, 6000, and 3000 Hz. Standard threshold shift was observed in 13 (2.34%, 49 (8.83%, 22 (3.96%, and 63 (11.35% subjects in the first and second years of follow-up in the right and left ears, respectively. Conclusions. This study has documented a high incidence of noise-induced hearing loss in tile and ceramic workers that would put stress on the importance of using hearing protection devices.

  20. Penrose tilings as model sets

    Science.gov (United States)

    Shutov, A. V.; Maleev, A. V.

    2015-11-01

    The Baake construction, based on generating a set of vertices of Penrose tilings as a model set, is refined. An algorithm and a corresponding computer program for constructing an uncountable set of locally indistinguishable Penrose tilings are developed proceeding from this refined construction. Based on an analysis of the parameters of tiling vertices, 62 versions of rhomb combinations at the tiling center are determined. The combinatorial structure of Penrose tiling worms is established. A concept of flip transformations of tilings is introduced that makes it possible to construct Penrose tilings that cannot be implemented in the Baake construction.

  1. Tile concrete base materials as substitutes for lead shielding installations diagnostic X-ray

    International Nuclear Information System (INIS)

    In this paper we study the damping characteristics in the energy range of medical diagnostic X-ray product XRAD trade name manufactured by Construction Radiotherapy Techniques (CTRADC) consisting of different composition tile with concrete base, for its characterization as a substitute shielding material lead.

  2. Assembly models for Papovaviridae based on tiling theory

    Science.gov (United States)

    Keef, T.; Taormina, A.; Twarock, R.

    2005-09-01

    A vital constituent of a virus is its protein shell, called the viral capsid, that encapsulates and hence provides protection for the viral genome. Assembly models are developed for viral capsids built from protein building blocks that can assume different local bonding structures in the capsid. This situation occurs, for example, for viruses in the family of Papovaviridae, which are linked to cancer and are hence of particular interest for the health sector. More specifically, the viral capsids of the (pseudo-) T = 7 particles in this family consist of pentamers that exhibit two different types of bonding structures. While this scenario cannot be described mathematically in terms of Caspar-Klug theory (Caspar D L D and Klug A 1962 Cold Spring Harbor Symp. Quant. Biol. 27 1), it can be modelled via tiling theory (Twarock R 2004 J. Theor. Biol. 226 477). The latter is used to encode the local bonding environment of the building blocks in a combinatorial structure, called the assembly tree, which is a basic ingredient in the derivation of assembly models for Papovaviridae along the lines of the equilibrium approach of Zlotnick (Zlotnick A 1994 J. Mol. Biol. 241 59). A phase space formalism is introduced to characterize the changes in the assembly pathways and intermediates triggered by the variations in the association energies characterizing the bonds between the building blocks in the capsid. Furthermore, the assembly pathways and concentrations of the statistically dominant assembly intermediates are determined. The example of Simian virus 40 is discussed in detail.

  3. A process-based transfer function approach to model tile-drain hydrographs

    Science.gov (United States)

    Arabi, Mazdak; Stillman, Jennifer S.; Govindaraju, Rao S.

    2006-09-01

    Tile-drain response to rainfall events is determined by unsaturated vertical flow to the water table, followed by horizontal saturated water movement. In this study, unsaturated vertical movement from the redistribution of water is modelled using a sharp-front approximation, and the saturated horizontal flow is modelled by an approximate solution to the Boussinesq equation. The unsaturated flow component models the fast response that is associated with the presence of preferential flow paths. By convoluting the responses of the two components, a transfer function is developed that predicts tile-drain response to unit amounts of infiltrated water. It is observed that the unsaturated flow component can be cast in a form that is linear in a power function of the infiltrated depth. Since the approach is process based, model parameter definitions are easily identified with soil properties at the field scale. Furthermore, it is demonstrated that the transfer function model parameters can be estimated from moment analysis. Using superposition, the transient tile-drain response to arbitrary amounts of infiltrated water can be constructed. Comparison with data measured from the Water Quality Field Station show that this approach provides a promising method for generating tile-drain response to rainfall events.

  4. Impact-acoustics-based health monitoring of tile-wall bonding integrity using principal component analysis

    Science.gov (United States)

    Tong, F.; Tso, S. K.; Hung, M. Y. Y.

    2006-06-01

    The use of the acoustic features extracted from the impact sounds for bonding integrity assessment has been extensively investigated. Nonetheless, considering the practical implementation of tile-wall non-destructive evaluation (NDE), the traditional defects classification method based directly on frequency-domain features has been of limited application because of the overlapping feature patterns corresponding to different classes whenever there is physical surface irregularity. The purpose of this paper is to explore the clustering and classification ability of principal component analysis (PCA) as applied to the impact-acoustics signature in tile-wall inspection with a view to mitigating the adverse influence of surface non-uniformity. A clustering analysis with signature acquired on sample slabs shows that impact-acoustics signatures of different bonding quality and different surface roughness are well separated into different clusters when using the first two principal components obtained. By adopting as inputs the feature vectors extracted with PCA applied, a multilayer back-propagation artificial neural network (ANN) classifier is developed for automatic health monitoring and defects classification of tile-walls. The inspection results obtained experimentally on the prepared sample slabs are presented and discussed, confirming the utility of the proposed method, particularly in dealing with tile surface irregularity.

  5. Clay materials for ceramic tiles from the Sassuolo District (Northern Apennines, Italy). Geology, composition and echnological properties

    OpenAIRE

    Dondi, M.

    1999-01-01

    In the Sassuolo area (northern Italy) there is the largest tilemaking district in the world, which has practically served over the past years as an industrial scale laboratory for assessing the technological properties of clays and their suitability for the production of wall and floor tiles. The local clays are recovered from different geological units and distinguished in mio principal types, with clearly differentiated compositions and technological properties: "marly clays" and "red shale...

  6. Tile-Based Two-Dimensional Phase Unwrapping for Digital Holography Using a Modular Framework

    OpenAIRE

    Antonopoulos, Georgios C.; Steltner, Benjamin; Heisterkamp, Alexander; Ripken, Tammo; Meyer, Heiko; Zhang, Heye

    2015-01-01

    A variety of physical and biomedical imaging techniques, such as digital holography, interferometric synthetic aperture radar (InSAR), or magnetic resonance imaging (MRI) enable measurement of the phase of a physical quantity additionally to its amplitude. However, the phase can commonly only be measured modulo 2π, as a so called wrapped phase map. Phase unwrapping is the process of obtaining the underlying physical phase map from the wrapped phase. Tile-based phase unwrapping algorithms oper...

  7. Tile Based Procedural Terrain Generation in Real-Time : A Study in Performance

    OpenAIRE

    Grelsson, David

    2014-01-01

    Context. Procedural Terrain Generation refers to the algorithmical creation of terrains with limited or no user input. Terrains are an important piece of content in many video games and other forms of simulations. Objectives. In this study a tile-based approach to creating endless terrains is investigated. The aim is to find if real-time performance is possible using the proposed method and possible performance increases from utilization of the GPU. Methods. An application that allows the use...

  8. Avaliação da eficiência térmica de telha reciclada à base de embalagens longa vida Evaluation of the thermal efficiency of roof tiles made of recycled long-life packaging

    Directory of Open Access Journals (Sweden)

    Juliano Fiorelli

    2009-04-01

    Full Text Available Neste trabalho se apresenta o estudo da influência de telha reciclada à base de embalagens longa vida (IBAPLAC® no conforto térmico de instalações zootécnicas. A pesquisa foi desenvolvida no Campus Experimental da Unesp de Dracena, SP. Foram construídos quatro protótipos, com área de 28 m² cada um, sendo um deles coberto com telha reciclada à base de embalagens longa vida e três protótipos de referência cobertos com telha cerâmica, telha cerâmica pintada de branco e telha de fibrocimento (Brasilit®. Dentro dos protótipos foram instalados termômetros de globo negro e termômetros de bulbo seco e bulbo úmido. Os dados foram coletados no verão de 2006/2007, totalizando 90 dias. Uma análise estatística por inferência e descritiva foi realizada utilizando-se valores médios de índice de temperatura de globo e umidade, carga térmica radiante e índice de temperatura e umidade, referente ao período. Pelos resultados obtidos é possível afirmar que a telha reciclada apresentou índices de conforto térmico semelhantes àqueles encontrados para as telhas cerâmicas, podendo ser indicada como opção de cobertura para instalações zootécnicas.This paper presents a study of the influence of roof tiles made of recycled long-life packaging (brand-name IBAPLAC® on the thermal comfort of zootechnical facilities. The research was conducted at UNESP's Experimental Campus at Dracena, State of São Paulo, Brazil. Four prototypes were built, each with an area of 28 m². One prototype was covered with roof tiles made of recycled long-life packing material and three reference prototypes were roofed with ceramic tiles, ceramic tiles painted white and fiber/cement tiles (Brasilit®, respectively. Black globe thermometers and dry and wet bulb thermometers were installed inside the prototypes. Temperatures inside the structures were recorded in the Summer of 2006/2007 over a 90-day period. A descriptive statistical analysis was made, based

  9. Optimal inventory reallocation to customer orders in ceramic tile companies characterized by the lack of homogeneity in the product (LHP); Reasignacion optima del inventario a pedidos en empresas ceramicas caracterizadas por la falta de homogeneidad en el producto (FHP)

    Energy Technology Data Exchange (ETDEWEB)

    Alemany, M. M. E.; Alarcon, F.; Oltra, R. F.; Lario, B. C.

    2013-02-01

    The lack of homogeneity in the product (LHP) is defined as the lack of uniformity required by the customer in the products. The LHP appears in companies where the final products obtained are not homogeneous, leading to the existence of different references (subtypes) of the same product. This lack of homogeneity is a problem when the client needs to be served through homogeneous units of a product and commit orders are based on planned quantities, whose final homogeneity characteristics are unknown at the time of acquiring the customer commitments. The frequent discrepancies caused by the LHP between planned homogeneous amounts and those actually obtained and available, can prevent the delivery of committed orders. To solve this problem, we propose a mathematical programming model for the reallocation of inventory in Make to Stock (MTS) ceramic tile companies characterized by the LHP that combines multiple objectives. The proposed mathematical model has been validated by its application to a real case of a ceramic company. The analysis of the obtained results indicates significant improvements in the number of orders completed on time and in sales revenue achieved. (Author) 33 refs.

  10. A new manufacturing plant for fired color tile

    Institute of Scientific and Technical Information of China (English)

    ZhaoZhoumin

    2005-01-01

    The article describes the new manufacturing plant for fired colour tile designed by Xian Research and Design Institute for Nei Mongolia Yinshan Ceramic Ltd. Company. The plant with an annual capacity of 10million fired color tiles.

  11. Use of the extraction residue of emeralds in a formulation mass of ceramic tiles; Utilizacao do residuo da extracao de esmeraldas em uma formulacao de massa de revestimento ceramico

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcante, R. F., E-mail: ronaldofcavalcante@gmail.com [Programa de Pos-Graduacao em Engenharia Mecanica - PPgEM - UFRN, Universidade Federal do Rio Grande do Norte, Lagoa Nova, RN (Brazil); Nascimento, R.M.; Paskocimas, C.A., E-mail: rmaribondo@ufrnet.br, E-mail: paskocimas_ca@hotmail.com [Departamento de Engenharia Materiais - DEMAT - Universidade Federal do Rio Grande do Norte, Lagoa Nova, RN (Brazil); Dutra, R.P.S., E-mail: ricardodutra@ct.ufpb.br [Departamento de Engenharia Materiais - DEMAT - UFPB - Universidade Federal de Pernambuco, Recife (Brazil)

    2012-04-15

    Companies involved in mining and beneficiation of emerald represent an important area of industrial development in Brazil, with a significant contribution to world production of this ore. As a result, large volumes of waste generated and emerald are constantly abandoned in the environment, contributing negatively to their preservation. On the other hand the interest in the use of mining waste as an additive in production of ceramic materials has grown among researchers in recent years. The ceramic industry is constantly seeking to expand the market for the sector and trying to improve product quality and increase the variety of applications. The technology of obtaining ceramic coating that uses waste from mining is still a largely unexplored market. Thus, the purpose of this study was to characterize the waste generated from mining emerald as well as to evaluate its potential use as raw material for production melting of ceramic tiles. Ceramic mixtures were prepared from raw materials characterized by X-ray fluorescence and X-ray diffraction. Five compositions were prepared using the waste codes of emeralds from 0%, 10%, 20%, 30% and 40%. Samples were prepared by pressing, sintered at 1000, 1100 and 1200 deg C and characterized to establish their mineralogical composition, water absorption, linear shrinkage and modulus of rupture. The results showed that the residue of emeralds studied can be embedded in the mass of ceramic tiles up to 20% in replacement of feldspar without compromising the end product properties. (author)

  12. Reliable and redundant FPGA based read-out design in the ATLAS TileCal Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Akerstedt, Henrik; Muschter, Steffen; Drake, Gary; Anderson, Kelby; Bohm, Christian; Oreglia, Mark; Tang, Fukun

    2015-10-01

    The Tile Calorimeter at ATLAS [1] is a hadron calorimeter based on steel plates and scintillating tiles read out by PMTs. The current read-out system uses standard ADCs and custom ASICs to digitize and temporarily store the data on the detector. However, only a subset of the data is actually read out to the counting room. The on-detector electronics will be replaced around 2023. To achieve the required reliability the upgraded system will be highly redundant. Here the ASICs will be replaced with Kintex-7 FPGAs from Xilinx. This, in addition to the use of multiple 10 Gbps optical read-out links, will allow a full read-out of all detector data. Due to the higher radiation levels expected when the beam luminosity is increased, opportunities for repairs will be less frequent. The circuitry and firmware must therefore be designed for sufficiently high reliability using redundancy and radiation tolerant components. Within a year, a hybrid demonstrator including the new readout system will be installed in one slice of the ATLAS Tile Calorimeter. This will allow the proposed upgrade to be thoroughly evaluated well before the planned 2023 deployment in all slices, especially with regard to long term reliability. Different firmware strategies alongside with their integration in the demonstrator are presented in the context of high reliability protection against hardware malfunction and radiation induced errors.

  13. Feature extraction for ultrasonic sensor based defect detection in ceramic components

    Science.gov (United States)

    Kesharaju, Manasa; Nagarajah, Romesh

    2014-02-01

    High density silicon carbide materials are commonly used as the ceramic element of hard armour inserts used in traditional body armour systems to reduce their weight, while providing improved hardness, strength and elastic response to stress. Currently, armour ceramic tiles are inspected visually offline using an X-ray technique that is time consuming and very expensive. In addition, from X-rays multiple defects are also misinterpreted as single defects. Therefore, to address these problems the ultrasonic non-destructive approach is being investigated. Ultrasound based inspection would be far more cost effective and reliable as the methodology is applicable for on-line quality control including implementation of accept/reject criteria. This paper describes a recently developed methodology to detect, locate and classify various manufacturing defects in ceramic tiles using sub band coding of ultrasonic test signals. The wavelet transform is applied to the ultrasonic signal and wavelet coefficients in the different frequency bands are extracted and used as input features to an artificial neural network (ANN) for purposes of signal classification. Two different classifiers, using artificial neural networks (supervised) and clustering (un-supervised) are supplied with features selected using Principal Component Analysis(PCA) and their classification performance compared. This investigation establishes experimentally that Principal Component Analysis(PCA) can be effectively used as a feature selection method that provides superior results for classifying various defects in the context of ultrasonic inspection in comparison with the X-ray technique.

  14. Building ceramic based on sludge

    Science.gov (United States)

    Szöke, A.-M.; Muntean, M.; Dumitrescu, O.; Bartalis, I.

    2013-12-01

    Because of the rapid evolution in the last decade of science and engineering materials, development of new advanced materials, particularly in construction, we must find solutions, namely, new performed materials, with functional and aesthetic qualities. In recent years, there have been made alternative attempts to reuse various types of wastes, including the incorporation of products in ceramic clay. This theme concerning the achievement of some durable, economic and ecological materials represents a high-level preoccupation in this domain, the problems related to the ecosystem being permanent issues of the century.

  15. Building ceramic based on sludge

    International Nuclear Information System (INIS)

    Because of the rapid evolution in the last decade of science and engineering materials, development of new advanced materials, particularly in construction, we must find solutions, namely, new performed materials, with functional and aesthetic qualities. In recent years, there have been made alternative attempts to reuse various types of wastes, including the incorporation of products in ceramic clay. This theme concerning the achievement of some durable, economic and ecological materials represents a high-level preoccupation in this domain, the problems related to the ecosystem being permanent issues of the century

  16. Comparing Titanium Release from Ceramic Tiles using a waste material characterization test - Influence of Calcium and Organic Matter concentrations

    DEFF Research Database (Denmark)

    Heggelund, Laura Roverskov; Hansen, Steffen Foss; Astrup, Thomas Fruergaard;

    2015-01-01

    deposited in landfills for construction and demolition waste or other types of landfills, depending on the local waste management system. Hence, the potential release of nano-Ti under landfill conditions is relevant to investigate. In this study we used a standard waste material characterization method to...... waste material to the landfill leachate, it is expected that the calcium and organic matter content in the liquid will affect the stability of the nanoparticles. The concentration of calcium in the landfill percolate is expected to decrease the stability of the particles due to compression of the...... immediately after the 24 hrs. test using single particle ICPMS and Transmission Electron Microscopy imaging. The preliminary results suggest that nanoparticulate titanium is released from both tiles – with and without nano-titanium dioxide coating. The size distributions of the released particles are similar...

  17. Fractal Tiling

    OpenAIRE

    Barnsley, Michael; Vince, Andrew

    2013-01-01

    A simple, yet unifying method is provided for the construction of tilings by tiles obtained from the attractor of an iterated function system (IFS). Many examples appearing in the literature in ad hoc ways, as well as new examples, can be constructed by this method. These tilings can be used to extend a fractal transformation defined on the attractor of a contractive IFS to a fractal transformation on the entire space upon which the IFS acts.

  18. Implementation of Tile Based Geographic Information System in Indonesia E-Government

    Directory of Open Access Journals (Sweden)

    Imairi Eitiveni

    2012-09-01

    Full Text Available Indonesia is the largest archipelago country in the world with complex topological conditions and has great potential of natural resources, but on the other hand susceptible to natural disasters, requiring a comprehensive spatial management. This led to the role of Geographic Information Systems/GIS becoming very crucial in the governance of Indonesia. However, implementation of GIS in Indonesia is not yet widespread. The study by Ramadhan et al (2011, from 91 E-Government systems that were examined, only 19% are implementing GIS. One of the possible constraints might be infrastructure problems, which is narrow bandwidth hence resulting in high response time. This issue is potentially reducing the efficiency of GIS functionality and user interest for the use of GIS. This paper proposes Tile based GIS technique that increases the speed of mapping application by displaying only the relevant layers. The system construction process applies Rapid Prototyping method. The next step is testing the system by real users of E-Government, which are citizens from various regions in Indonesia. The results of the test analysis showed statistically significant difference between static and tile based mapping system.

  19. Tile adhesive production by Inorganic materials

    Directory of Open Access Journals (Sweden)

    Fasil Alemayehu Hayilu

    2013-07-01

    Full Text Available In modern construction, ceramic tile and mosaic which are used for finishing and decoration are attached to the surface by using tile adhesives. It was a long way for tiling technology to arrive at the current cement based modified adhesive. The development in additives and modifier are the paramount factor to improve workability, higher flexibility, and better adhesion. In this document tile adhesive has been produced for economical and high performance formulation. These products have been produced by considering the effect of aggregate. These two products with different size of aggregate have been compared and tested. The test made was slip, bending, and compression test. Economical formulation consists of components like cement, quartz sand, cellulose ether and tartaric acid. But high performance consists of limestone and cellulose fiber in addition to these components. The modifier added has enhanced the final product resistance to sliding, bending and compression strength. In terms of compression strength test about 17.27% high performance is stronger than economical formulation. And in addition high performance is stronger than economical formulation by about 16.89% in terms of bending strength. The other thing is the effect of grain size, the component that has low grain size have shown great strength and resistant to slide.

  20. Reliable and redundant FPGA based read-out design in the ATLAS TileCal Demonstrator

    CERN Document Server

    Akerstedt, H; The ATLAS collaboration; Drake, Gary; Anderson, Kelby; Bohm, C; Oreglia, Mark; Tang, Fukun

    2015-01-01

    The Tile Calorimeter at ATLAS is a hadron calorimeter based on steel plates and scintillating tiles read out by PMTs. The current read-out system uses standard ADCs and custom ASICs to digitize and temporarily store the data on the detector. However, only a subset of the data is actually read out to the counting room. The on-detector electronics will be replaced around 2023. To achieve the required reliability the upgraded system will be highly redundant. Here the ASICs will be replaced with Kintex-7 FPGAs from Xilinx. This, in addition to the use of multiple 10 Gbps optical read-out links, will allow a full read-out of all detector data. Due to the higher radiation levels expected when the beam luminosity is increased, opportunities for repairs will be less frequent. The circuitry and firmware must therefore be designed for sufficiently high reliability using redundancy and radiation tolerant components. Within a year, a hybrid demonstrator including the new read-out system will be installed in one slice of ...

  1. Some Generalizations of the Pinwheel Tiling

    OpenAIRE

    Sadun, Lorenzo

    1997-01-01

    We introduce a new family of nonperiodic tilings, based on a substitution rule that generalizes the pinwheel tiling of Conway and Radin. In each tiling the tiles are similar to a single triangular prototile. In a countable number of cases, the tiles appear in a finite number of sizes and an infinite number of orientations. These tilings generally do not meet full-edge to full-edge, but CAN be forced through local matching rules. In a countable number of cases, the tiles appear in a finite num...

  2. Development of SiPM-based scintillator tile detectors for a multi-layer fast neutron tracker

    OpenAIRE

    Jakubek J.; Uher J.; Prokopovich D.; Preston R.

    2012-01-01

    We are developing thin tile scintillator detectors with silicon photomultiplier (SiPM) readout for use in a multi-layer fast-neutron tracker. The tracker is based on interleaved Timepix and plastic scintillator layers. The thin 15 × 15 × 2 mm plastic scintillators require suitable optical readout in order to detect and measure the energy lost by energetic protons that have been recoiled by fast neutrons. Our first prototype used dual SiPMs, coupled to opposite edges of the scintillator tile u...

  3. Tough hybrid ceramic-based material with high strength

    International Nuclear Information System (INIS)

    This study describes a tough and strong hybrid ceramic material consisting of platelet-like zirconium compounds and metal. A mixture of boron carbide and excess zirconium powder was heated to 1900 °C using a liquid-phase reaction sintering technique to produce a platelet-like ZrB2-based hybrid ceramic bonded by a thin zirconium layer. The platelet-like ZrB2 grains were randomly present in the as-sintered hybrid ceramic. Relative to non-hybrid ceramics, the fracture toughness and flexural strength of the hybrid ceramic increased by approximately 2-fold.

  4. Development of LiF tile neutron shield and measurement of tritium release from it

    International Nuclear Information System (INIS)

    For neutron capture therapy of cancer, the neutron irradiation field with low gamma-ray is essential for selective treatment. From various lithium compounds, lithium fluoride LiF was selected as the shielding material for the present purpose, because of 1 large lithium density, 2 chemical stability, 3 easy treatment for nonpoison, and 4 small induced activity. In order to utilized LiF in pure chemical form, we have developed LiF tile, although as yet few investigations have been made of sintering a material in fluoride form. From viewpoint of ceramic technology, some new facts have been observed. The behavior of tritium, produced by the reaction of 6Li(n, α)T, in LiF tile was experimentally clarified. Tritium is released from LiF tile in two processes: (1) tritium released by recoil immediately after neutron irradiation, (2) tritium released with temperature condition and elasped time after temporaty containment in LiF tile. The former tritium was trapped in ethanol and measured with a liquid scintillator. While the latter was released in a loop by heating the irradiated tile and measured with a gas-flow-type tritium monitor. The following facts have been clarified: (1) Amount of recoiled tritium from LiF tile is --0.11 μCi/cm2/1014 nvt. (2) Most of tritium produced in LiF tile is contained in the tile itself. (3) Tritium contained in LiF tile is not released at temperature less than 3000C. (4) Contained tritium is released mainly at temperature between 400 -- 6500C. (5) The higher temperature at which LiF tile was sintered, the better containment of tritium. We have finally succeeded in developing LiF tile with low tritium release as neutron shielding material, which is now on sale in commercial base. (author)

  5. 竹炭对粉煤灰陶瓷砖结构及性能的影响%Effect of Bamboo Charcoal on Microstructure and Performance of Fly Ash Ceramic Tile

    Institute of Scientific and Technical Information of China (English)

    杨辉; 李文彦; 郭兴忠; 涂志龙

    2011-01-01

    With fly ash and gold tailings as raw materials, bamboo charcoal as additive, fly ash ceramic tiles were prepared by drying pressing-firing method, and the effect of bamboo charcoal's addition and firing temperature on the properties, compositions and microstructure of the ceramic tiles were studied. The results show that the fly ash ceramic tile can be prepared with high mechanical strength and high porosity, and it has porous structure with quartz and mullite as main phases. When m(bamboo charcoal):m(fly ash) is 5:70 and the firing temperature is 1 250℃, the ceramic tile has excellent comprehensive properties, its fracture strength is 600. 1 N, water absorption is 8. 29%, and apparent porosity is 16. 02%. The comprehensive properties can meet the requirement set forth in GB/T 4100-2006 BⅡ, and it also possesses specific surface area of 11. 1 m2/g. It is indicated that the material is expected to be a new functional indoor decoration material.%采用粉煤灰、黄金尾矿为主要原料,添加不同掺量的竹炭,通过干压成型-高温烧成法制得粉煤灰陶瓷砖,分析了竹炭掺量及烧成温度对粉煤灰陶瓷砖的物化性能、物相组成及显微结构的影响规律.结果表明:以粉煤灰、黄金尾矿和竹炭可以制备出显气孔率和强度较高、吸水率较低的粉煤灰陶瓷砖,其物相主要为石英相与莫来石相;在m(竹炭)∶m(粉煤灰)为5∶70,烧成温度为1 250℃时,陶瓷砖具有较好的综合性能,其破坏强度可达600.1 N,吸水率为8.29%,显气孔率为16.02%,达到GB/T 4100-2006附录K中对BⅡ类炻质砖的性能要求,且该材料的比表面积为11.1 m2/g,具备一定的吸附功能,有望成为一种新型的内墙功能装饰材料.

  6. Thermal energy consumption and carbon dioxide emissions in ceramic tile manufacture - Analysis of the Spanish and Brazilian industries; Consumo de energia termica y emisiones de dioxido de carbono en la fabricacion de baldosas ceramicas Analisis de las industrias Espanola y Brasilena

    Energy Technology Data Exchange (ETDEWEB)

    Monfort, E.; Mezquita, A.; Vaquer, E.; Mallol, G.; Alves, H. J.; Boschi, A. O.

    2012-11-01

    Spain and Brazil are two of the world's biggest ceramic tile producers. The tile manufacturing process consumes a great quantity of thermal energy that, in these two countries, is mainly obtained from natural gas combustion, which entails CO{sub 2} emission, a greenhouse gas. This study presents a comparative analysis of the thermal energy consumption and CO{sub 2} emissions in the ceramic tile manufacturing process in Spain and Brazil, in terms of the different production technologies and different products made. The energy consumption and CO{sub 2} emissions in ceramic tile manufacture by the wet process are very similar in both countries. In the dry process used in Brazil, less thermal energy is consumed and less CO{sub 2} is emitted than in the wet process, but it is a process that is only used in manufacturing one particular type of product, which exhibits certain technical limitations. While in Spain the use of cogeneration systems in spray-dryers improves significantly the global energy efficiency. The average energy consumption in the different process stages, in both countries, lies within the range indicated in the Reference Document on Best Available Techniques in the Ceramic Manufacturing Industry (BREF of the Ceramic Manufacturing Industry) of the European Union. (Author) 14 refs.

  7. Modeling and simulation of the atomization process in the ceramic tile industry; Modelagem e simulacao do processo de atomizacao na industria de revestimento ceramico

    Energy Technology Data Exchange (ETDEWEB)

    Favalli, Renata Cristina

    2002-07-01

    The aim of the present work is to numerically simulate the behaviour of the drying system for several sets of operating conditions in order to improve and optimize this process. However, the mathematical modeling adopted here can be employed to simulate other systems such as the processes that occur in liquid-fueled engines with direct spray injection and ceramic spraying for hard surfacing. Then, mathematical and physical models were established to simulate the interaction of continuous and disperse phases in drying processes of ceramic slurries. Solving the set of governing coupled partial differential equations, it is possible to study the influence of drying air on the atomized droplets of alumina slurry, and vice-versa. The materials used as continuous and disperse phase, air and alumina slurry respectively, are representative since any kind of gas and slurry can be used if its thermodynamic and transport properties are known. Several experimental tests were carried out in a spray dryer in the 'Laboratorio de Insumos', at IPEN - Instituto de Pesquisas Energeticas e Nucleares for different sets of operating conditions: initial temperature of the drying air, the gas flow rate, the slurry feed rate and atomiser configuration among others. Measurements of the wet and the dry bulb temperatures were made in some experimental tests to allow the calculations of the air humidity. The dynamic pressure were also measured in order to determine the gas flow rate. Some samples of the material used in the tile industry and of the one produced at IPEN were analysed to determine: the morphology of the atomized material and the range of granules diameter through scanning electron microscopy; the amount of pores and the bulk density through porosimetry; the residual moisture of the material through thermogravimetry; and the granulometric distribution of granules and particles through laser diffraction. Important information about the process and the final material are

  8. Optimising the bioreceptivity of porous glass tiles based on colonization by the alga Chlorella vulgaris.

    Science.gov (United States)

    Ferrándiz-Mas, V; Bond, T; Zhang, Z; Melchiorri, J; Cheeseman, C R

    2016-09-01

    Green façades on buildings can mitigate greenhouse gas emissions. An option to obtain green facades is through the natural colonisation of construction materials. This can be achieved by engineering bioreceptive materials. Bioreceptivity is the susceptibility of a material to be colonised by living organisms. The aim of this research was to develop tiles made by sintering granular waste glass that were optimised for bioreceptivity of organisms capable of photosynthesis. Tiles were produced by pressing recycled soda-lime glass with a controlled particle size distribution and sintering compacted samples at temperatures between 680 and 740°C. The primary bioreceptivity of the tiles was evaluated by quantifying colonisation by the algae Chlorella vulgaris (C. vulgaris), which was selected as a model photosynthetic micro-organism. Concentrations of C. vulgaris were measured using chlorophyll-a extraction. Relationships between bioreceptivity and the properties of the porous glass tile, including porosity, sorptivity, translucency and pH are reported. Capillary porosity and water sorptivity were the key factors influencing the bioreceptivity of porous glass. Maximum C. vulgaris growth and colonisation was obtained for tiles sintered at 700°C, with chlorophyll-a concentrations reaching up to 11.1±0.4μg/cm(2) of tile. Bioreceptivity was positively correlated with sorptivity and porosity and negatively correlated with light transmittance. The research demonstrates that the microstructure of porous glass, determined by the processing conditions, significantly influences bioreceptivity. Porous glass tiles with high bioreceptivity that are colonised by photosynthetic algae have the potential to form carbon-negative façades for buildings and green infrastructure. PMID:27135568

  9. Ceramics based on calcium pyrophosphate nanopowders

    Directory of Open Access Journals (Sweden)

    Tatiana V. Safronova

    2013-03-01

    Full Text Available Present work is aimed at the fabrication of resorbable bioceramics based on calcium pyrophosphate (CPP from the synthesized powders of amorphous hydrated calcium pyrophosphate (AHCPP. Amorphous hydratedcalcium pyrophosphate in the form of nanopowders was precipitated from Ca(NO3 2 and (NH4 4P2O7 solutions at room temperature in the presence of PO3– ions. Crystalline CPP powder was fabricated from AHCPP by its thermal decomposition at 600 °C and consisted of β- and α- phase. Small particles, with the size less than 200 nm, were formed promoting sintering of the ceramic material. The final sample, sintered at 900 °C, exhibits microstructure with submicron grains, apparent density of 87% of theoretical density (TD and demonstrates tensile strength of 70 MPa.

  10. Tiled Polymorphic Temporal Media

    OpenAIRE

    Hudak, Paul; Janin, David

    2014-01-01

    International audience Tiled Polymorphic Temporal Media (Tiled PTM) is an algebraic approach to specifying the composition of multimedia values having an inherent temporal quality --- for example sound clips, musical scores, computer animations, and video clips. Mathematically, one can think of a tiled PTM as a tiling in the one dimension of time. A tiled PTM value has two synchronization marks that specify, via an effective notion of tiled product, how the tiled PTMs are positioned in tim...

  11. Fractal dual substitution tilings

    OpenAIRE

    Frank, Natalie Priebe; Webster, Samuel B. G.; Whittaker, Michael F.

    2014-01-01

    Starting with a substitution tiling, we demonstrate a method for constructing infinitely many new substitution tilings. Each of these new tilings is derived from a graph iterated function system and the tiles have fractal boundary. We show that each of the new tilings is mutually locally derivable to the original tiling. Thus, at the tiling space level, the new substitution rules are expressing geometric and combinatorial, rather than topological, features of the original. Our method is easy ...

  12. Talk about Han eaves tile art in our country

    Institute of Scientific and Technical Information of China (English)

    刘泽艺

    2015-01-01

    The Han Dynasty is the first in the history of the unified and powerful country. It is a huge momentum has also affected the development of art, especially the art of eaves tile. Pattern of Han eaves tile is the art of the Chinese nation in the classic, rich artistic value for tile study of traditional ceramic art is very necessary in China. Through the research on Eave Tile Art, can be in-jected into the power of ceramic art in China's new development.

  13. Surface Mosaic Synthesis with Irregular Tiles.

    Science.gov (United States)

    Hu, Wenchao; Chen, Zhonggui; Pan, Hao; Yu, Yizhou; Grinspun, Eitan; Wang, Wenping

    2016-03-01

    Mosaics are widely used for surface decoration to produce appealing visual effects. We present a method for synthesizing digital surface mosaics with irregularly shaped tiles, which are a type of tiles often used for mosaics design. Our method employs both continuous optimization and combinatorial optimization to improve tile arrangement. In the continuous optimization step, we iteratively partition the base surface into approximate Voronoi regions of the tiles and optimize the positions and orientations of the tiles to achieve a tight fit. Combination optimization performs tile permutation and replacement to further increase surface coverage and diversify tile selection. The alternative applications of these two optimization steps lead to rich combination of tiles and high surface coverage. We demonstrate the effectiveness of our solution with extensive experiments and comparisons. PMID:26561463

  14. Performance of the Tile PreProcessor Demonstrator for the ATLAS Tile Calorimeter Phase II Upgrade

    CERN Document Server

    Carrio Argos, Fernando; The ATLAS collaboration

    2015-01-01

    The Tile Calorimeter PreProcessor (TilePPr) demonstrator is a high performance double AMC board based on FPGA resources and QSFP modules. This board has been designed in the framework of the ATLAS Tile Calorimeter (TileCal) Demonstrator Project for the Phase II Upgrade as the first stage of the back-end electronics. The TilePPr demonstrator has been conceived for receiving and processing the data coming from the front-end electronics of the TileCal Demonstrator module, as well as for configuring it. Moreover, the TilePPr demonstrator handles the communication with the Detector Control System to monitor and control the front-end electronics. The TilePPr demonstrator represents 1/8 of the final TilePPr that will be designed and installed into the detector for the ATLAS Phase II Upgrade.

  15. COMPRESSIVE STRENGTH CHARACTERISTICS OF TILE WASTE CONCRETE

    OpenAIRE

    Ofonime A. Harry*, Ifiok E. Ekop

    2016-01-01

    Increase in the use of concrete in construction industry in Nigeria has led to the rise in the cost of its constituent material. This has necessitated research into the use of alternative material which is cheaper and can produce a comparable level of strength as the conventionally used ones. This paper present the results of an investigation into the compressive strength characteristics of concrete made with ceramic tile waste as coarse aggregates. The percentage of tile waste was varied in ...

  16. Development of SiPM-based scintillator tile detectors for a multi-layer fast neutron tracker

    Directory of Open Access Journals (Sweden)

    Jakubek J.

    2012-10-01

    Full Text Available We are developing thin tile scintillator detectors with silicon photomultiplier (SiPM readout for use in a multi-layer fast-neutron tracker. The tracker is based on interleaved Timepix and plastic scintillator layers. The thin 15 × 15 × 2 mm plastic scintillators require suitable optical readout in order to detect and measure the energy lost by energetic protons that have been recoiled by fast neutrons. Our first prototype used dual SiPMs, coupled to opposite edges of the scintillator tile using light-guides. An alternative readout geometry was designed in an effort to increase the fraction of scintillation light detected by the SiPMs. The new prototype uses a larger SiPM array to cover the entire top face of the tile. This paper details the comparative performance of the two prototype designs. A deuterium-tritium (DT fast-neutron source was used to compare the relative light collection efficiency of the two designs. A collimated UV light source was scanned across the detector face to map the uniformity. The new prototype was found to have 9.5 times better light collection efficiency over the original design. Both prototypes exhibit spatial non-uniformity in their response. Methods of correcting this non-uniformity are discussed.

  17. Development of high-density ceramic composites for ballistic applications

    International Nuclear Information System (INIS)

    The application of ceramic composites for ballistic application has been generally developed with ceramics of low density, between 2.5 and 4.5 g/cm2. These materials have offered good performance in defeating small-caliber penetrators, but can suffer time-dependent degradation effects when thicker ceramic tiles are needed to defeat modem, longer, heavy metal penetrators that erode rather than break up. This paper addresses the ongoing development, fabrication procedures, analysis, and ballistic evaluation of thinner, denser ceramics for use in armor applications. Nuclear Metals Incorporated (NMI) developed a process for the manufacture of depleted uranium (DU) ceramics. Samples of the ceramics have been supplied to the US Army Research Laboratory (ARL) as part of an unfunded cooperative study agreement. The fabrication processes used, characterization of the ceramic, and a ballistic comparison between the DU-based ceramic with baseline Al2O3 will be presented

  18. Programmable DNA tile self-assembly using a hierarchical sub-tile strategy

    International Nuclear Information System (INIS)

    DNA tile based self-assembly provides a bottom-up approach to construct desired nanostructures. DNA tiles have been directly constructed from ssDNA and readily self-assembled into 2D lattices and 3D superstructures. However, for more complex lattice designs including algorithmic assemblies requiring larger tile sets, a more modular approach could prove useful. This paper reports a new DNA ‘sub-tile’ strategy to easily create whole families of programmable tiles. Here, we demonstrate the stability and flexibility of our sub-tile structures by constructing 3-, 4- and 6-arm DNA tiles that are subsequently assembled into 2D lattices and 3D nanotubes according to a hierarchical design. Assembly of sub-tiles, tiles, and superstructures was analyzed using polyacrylamide gel electrophoresis and atomic force microscopy. DNA tile self-assembly methods provide a bottom-up approach to create desired nanostructures; the sub-tile strategy adds a useful new layer to this technique. Complex units can be made from simple parts. The sub-tile approach enables the rapid redesign and prototyping of complex DNA tile sets and tiles with asymmetric designs. (paper)

  19. Planejamento estatístico de experimentos aplicado ao desenvolvimento de formulações para revestimentos cerâmicos Statistical design of experiments applied to the development of formulations for ceramic tiles

    Directory of Open Access Journals (Sweden)

    R. T. Zauberas

    2004-03-01

    Full Text Available Este trabalho avalia a utilização de técnicas de planejamento estatístico de experimentos com misturas envolvendo variáveis de processo no estudo de formulações para a produção de revestimentos cerâmicos, buscando minimizar o caráter empírico encontrado industrialmente nesta etapa do processamento. Misturas de três matérias-primas (argila, feldspato e areia, utilizadas industrialmente para a produção de revestimentos, foram ensaiadas sob condições padronizadas visando à quantificação da influência de cada matéria-prima na resistência mecânica e na absorção de água das peças após a queima. As influências de duas variáveis de processo, pressão de compactação e temperatura de queima, também foram avaliadas. Os resultados obtidos demonstram o potencial de utilização das técnicas de planejamento estatístico de experimentos no estudo e desenvolvimento de formulações para revestimentos cerâmicos.This work evaluates the use of statistical design of experiment on the development of formulations for ceramic tiles production, trying to minimise the empirical character industrially found on this processing step. Mixtures of three raw materials used in tile production (clay, feldspar and quartz sand, were processed under standardised conditions, aiming at the quantification of the contribution of each raw material influence on mechanical strength and water absorption of the bodies after sintering. The influences of two process variables, pressing and sintering temperature, were also evaluated. Results obtained show the potential on utilising statistical design of experiments with mixtures and process variables techniques on the study and development of formulations for ceramic tiles.

  20. Integrated thick-film nanostructures based on spinel ceramics

    OpenAIRE

    Klym, Halyna; Hadzaman, Ivan; Shpotyuk, Oleh; Brunner, Michael

    2014-01-01

    Integrated temperature-humidity-sensitive thick-film structures based on spinel-type semiconducting ceramics of different chemical compositions and magnesium aluminate ceramics were prepared and studied. It is shown that temperature-sensitive thick-film structures possess good electrophysical characteristics in the region from 298 to 358 K. The change of electrical resistance in integrated thick-film structures is 1 order, but these elements are stable in time and can be successfully used for...

  1. Fabrication of ordered porous silicon carbide-based ceramics

    OpenAIRE

    Majoulet, Olivier

    2012-01-01

    SiC based non-oxide type ceramics have been largely studied due to high thermostructural properties.In particular, Silicoboron carbonitrides (SiBCN) display high mechanic reliability and stay stableuntil temperature such as 2200 °C due to a low atomic mobility in their structure. The developpementof the Polymer Derived Ceramics (PDCs) route played a major role in the production of technicalceramics with controlled properties. Through the thermolysis of preceramic polymers, a large rangeof cer...

  2. Design of an FPGA-based embedded system for the ATLAS Tile Calorimeter front-end electronics test-bench

    International Nuclear Information System (INIS)

    The portable test-bench for the certification of the ATLAS tile hadronic calorimeter front-end electronics has been redesigned for the present Long Shutdown (LS1) of LHC, improving its portability and expanding its functionalities. This paper presents a new test-bench based on a Xilinx Virtex-5 FPGA that implements an embedded system using a PowerPC 440 microprocessor hard core and custom IP cores. A light Linux version runs on the PowerPC microprocessor and handles the IP cores which implement the different functionalities needed to perform the desired tests such as TTCvi emulation, G-Link decoding, ADC control and data reception

  3. Lutetium oxide-based transparent ceramic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Seeley, Zachary; Cherepy, Nerine; Kuntz, Joshua; Payne, Stephen A.

    2016-01-19

    In one embodiment, a transparent ceramic of sintered nanoparticles includes gadolinium lutetium oxide doped with europium having a chemical composition (Lu.sub.1-xGd.sub.x).sub.2-YEu.sub.YO.sub.3, where X is any value within a range from about 0.05 to about 0.45 and Y is any value within a range from about 0.01 to about 0.2, and where the transparent ceramic exhibits a transparency characterized by a scatter coefficient of less than about 10%/cm. In another embodiment, a transparent ceramic scintillator of sintered nanoparticles, includes a body of sintered nanoparticles including gadolinium lutetium oxide doped with a rare earth activator (RE) having a chemical composition (Lu.sub.1-xGd.sub.x).sub.2-YRE.sub.YO.sub.3, where RE is selected from the group consisting of: Sm, Eu, Tb, and Dy, where the transparent ceramic exhibits a transparency characterized by a scatter coefficient of less than about 10%/cm.

  4. Efficient Tiled Loop Generation: D-Tiling

    Science.gov (United States)

    Kim, Daegon; Rajopadhye, Sanjay

    Tiling is an important loop optimization for exposing coarse-grained parallelism and enhancing data locality. Tiled loop generation from an arbitrarily shaped polyhedron is a well studied problem. Except for the special case of a rectangular iteration space, the tiled loop generation problem has been long believed to require heavy machinery such as Fourier-Motzkin elimination and projection, and hence to have an exponential complexity. In this paper we propose a simple and efficient tiled loop generation technique similar to that for a rectangular iteration space. In our technique, each loop bound is adjusted only once, syntactically and independently. Therefore, our algorithm runs linearly with the number of loop bounds. Despite its simplicity, we retain several advantages of recent tiled code generation schemes - unified generation for fixed, parameterized and hybrid tiled loops, scalability for multi-level tiled loop generation with the ability to separate full tiles at any levels, and compact code. We also explore various schemes for multi-level tiled loop generation. We formally prove the correctness of our scheme and experimentally validate that the efficiency of our technique is comparable to existing parameterized tiled loop generation approaches. Our experimental results also show that multi-level tiled loop generation schemes have an impact on performance of generated code. The fact that our scheme can be implemented without sophisticated machinery makes it well suited for autotuners and production compilers.

  5. Wettable Ceramic-Based Drained Cathode Technology for Aluminum Electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    J.N. Bruggeman; T.R. Alcorn; R. Jeltsch; T. Mroz

    2003-01-09

    The goal of the project was to develop the ceramic based materials, technology, and necessary engineering packages to retrofit existing aluminum reduction cells in order to reduce energy consumption required for making primary aluminum. The ceramic materials would be used in a drained cathode configuration which would provide a stable, molten aluminum wetted cathode surface, allowing the reduction of the anode-cathode distance, thereby reducing the energy consumption. This multi-tasked project was divided into three major tasks: (1) Manufacturing and laboratory scale testing/evaluation of the ceramic materials, (2) Pilot scale testing of qualified compositions from the first task, and (3) Designing, retrofitting, and testing the ceramic materials in industrial cells at Kaiser Mead plant in Spokane, Washington. Specific description of these major tasks can be found in Appendix A - Project Scope. Due to the power situation in the northwest, the Mead facility was closed, thus preventing the industrial cell testing.

  6. Actor-Critic Algorithm Based on Tile Coding and Model Learning%基于Tile Coding编码和模型学习的Actor-Critic算法

    Institute of Scientific and Technical Information of China (English)

    金玉净; 朱文文; 伏玉琛; 刘全

    2014-01-01

    Actor-Critic是一类具有较好性能及收敛保证的强化学习方法,然而,Agent在学习和改进策略的过程中并没有对环境的动态性进行学习,导致Actor-Critic方法的性能受到一定限制.此外,Actor-Critic方法中需要近似地表示策略以及值函数,其中状态和动作的编码方法以及参数对Actor-Critic方法有重要的影响.Tile Coding编码具有简单易用、计算时间复杂度较低等优点,因此,将Tile Coding编码与基于模型的Actor-Critic方法结合,并将所得算法应用于强化学习仿真实验.实验结果表明,所得算法具有较好的性能.

  7. Cellular ceramics made from porcelain tile polishing wastes: influence of sintering time; Ceramicas cellulares obtidas a partir de residuo de polimento de porcelanato: influencia do tempo de sinterizacao

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, A.F.; Zanelatto, C.C.; Uggioni, E. [Universidade do Extremo Sul Catarinense (UNESC), Criciuma, SC (Brazil). Dept. de Engenharia de Materiais; Bernardin, A.M., E-mail: amb@unesc.ne [Servico Nacional de Aprendizagem Industrial, Tijucas, SC (Brazil). Tecnologia em Ceramica

    2009-07-01

    This paper deals with the physical, microstructural and mechanical characterization of cellular ceramics made from porcelain polishing wastes, which were expanded by the bubble formation technique during the sintering process. The microstructure, linear expansion, bulk density (mercury immersion) and mechanical behavior (compressive strength) were determined to characterize the glass foam obtained. Moreover, the porcellaneous residue was characterized by chemical and phase analyses, particle size (laser diffraction) and thermal behavior. As a result, the higher the soaking time during heat treatment at 1200 deg C the lower the density obtained for the cellular ceramic due to CO{sub 2} expansion, and lower the mechanical strength of the samples. The microstructure shows spherical cells and completely closed pores, resulting in a cheap way to obtain low density material with adequate mechanical strength, avoiding the disposal of wastes from the ceramic industry. (author)

  8. M dwarfs in the b201 tile of the VVV survey: Colour-based Selection, Spectral Types and Light Curves

    CERN Document Server

    Rojas-Ayala, Bárbara; Minniti, Dante; Saito, Roberto K; Surot, Francisco

    2014-01-01

    The intrinsically faint M dwarfs are the most numerous stars in the Galaxy, have main-sequence lifetimes longer than the Hubble time, and host some of the most interesting planetary systems known to date. Their identification and classification throughout the Galaxy is crucial to unravel the processes involved in the formation of planets, stars and the Milky Way. The ESO Public Survey VVV is a deep near-IR survey mapping the Galactic bulge and southern plane. The VVV b201 tile, located in the border of the bulge, was specifically selected for the characterisation of M dwarfs. We used VISTA photometry to identify M dwarfs in the VVV b201 tile, to estimate their subtypes, and to search for transit-like light curves from the first 26 epochs of the survey. UKIDSS photometry from SDSS spectroscopically identified M dwarfs was used to calculate their expected colours in the $YJHK_s$ VISTA system. A colour-based spectral subtype calibration was computed. Possible giants were identified by a $(J-K_s, H_{J})$ reduced ...

  9. Tilings of a Domain on a Hexagon Mesh with Balanced 3-Tiles

    OpenAIRE

    Radenne, Gilles

    2001-01-01

    In this article, we study the question of tilings on a hexagon mesh with balanced 3-tiles. This problem has been studied by Conway and Lagarias in [CL90], by studying the tiling groups, in fact a group containing the tiling-groups, and their Cayley graphs. We will use two different approaches. The first one is based on matchings in bipartite graphs, which in this case are in correspondance with tilings of domains by lozenges, and thus can be efficiently studied, using Thurston's algorithm (se...

  10. Evaluation of borax solid wastes in production of frits suitable for fast single-fired wall tile opaque glass–ceramic glazes

    Indian Academy of Sciences (India)

    K Pekkan; B Karasu

    2010-04-01

    Zircon (zirconium silicate, ZrSiO4) is the main opacifier of glossy, opaque, white-coloured, fritbased wall tile glazes. However, zirconia containing frits employed in the preparation of these glazes raise the production cost limiting zircon usage as a raw material at an industrial scale. Therefore, there have been several searches on seeking for alternative frit compositions with lower or without zirconia content. Consequently, positive outcomes were recently reported. With the present study, 1.5–5% of borax concentrator waste replaced certain level of acid boric for B2O3 content in a low zircon containing frit recipe. It is confirmed that waste contribution did not distort the surface properties of the fast single-fired wall tile opaque glazes. Zircon was found to be the main crystal phase of the glazes in laboratory trials. Industrial applications revealed that shorter firing cycles lead to zircon and petedunnite (CaZnSi2O6) formation in the CW-4 glaze.

  11. Reciclagem do resíduo da serragem de calcário laminado para produção de blocos cerâmicos Recycling of laminated calcite tile sawing waste for the production of ceramic bricks

    Directory of Open Access Journals (Sweden)

    Romualdo R. Menezes

    2010-12-01

    Full Text Available As indústrias da mineração e beneficiamento de calcário laminado representam um importante segmento econômico do Estado do Ceará, entretanto produzem uma grande quantidade de resíduos, que poluem e agridem o meio ambiente. Assim, esse trabalho tem por objetivo a caracterização do resíduo da serragem da Pedra Cariri e a avaliação de sua aplicabilidade como matéria-prima cerâmica alternativa para a produção de telhas e blocos cerâmicos. O resíduo foi caracterizado através da determinação de sua composição química e mineralógica, por difração de raios X, análise térmica diferencial, distribuição de tamanho de partículas e análise morfológica por microscopia eletrônica de varredura. Foram formuladas composições contendo o resíduo e confeccionados corpos-de-prova por prensagem. Os corpos-de-prova foram queimados e, em seguida, foram determinados a absorção de água e o módulo de ruptura à flexão. Pode-se concluir que o resíduo é constituído por calcita e dolomita, que apresenta elevada finura e que é possível a incorporação de até 10% de resíduo em formulações para a produção de telhas e blocos cerâmicos.The mining and processing industries of laminated calcite tile are an important economic sector in the State of Ceará. However, they generate a large amount of wastes, which are a source of contamination and environmental pollution. This study aimed to characterize the laminated calcite tile sawing waste and evaluate its suitability as an alternative ceramic raw material for the production of bricks and roof tiles. The waste was characterized by chemical composition determination, X-ray diffraction, differential thermal analyses, particle size distribution determination, and morphological analysis by electronic scanning microscopy. Several formulations were prepared and sample bodies were prepared by uniaxial pressing. The sample bodies were fired at different temperatures. Sintered samples

  12. Los Sistemas Productivos, el Aprendizaje Interno y los Resultados del Área de Producción de Baldosas-Cerámicas Production Systems, Internal Learning and Results of the Manufacturing Area of Ceramic Tile Manufacturers

    Directory of Open Access Journals (Sweden)

    Juan A Marin-Garcia

    2009-01-01

    Full Text Available El objetivo de la investigación es comprobar la validez del modelo universal de gestión en la estrategia de producción en el sector de fabricantes de pavimentos y baldosas cerámicas españoles. El trabajo se centra en las decisiones de infraestructura, y pretende resaltar el efecto de los recursos internos y externos sobre la ventaja competitiva del área de producción de las empresas. Los datos utilizados corresponden a 76 empresas españolas fabricantes de pavimentos cerámicos. Los resultados obtenidos permiten comprobar que en este sector los recursos implantados guardan poca relación con las prioridades manifestadas. Además, se demuestra que la ventaja competitiva está más explicada por el aprendizaje interno que por las prácticas de producción implantadas.The objective of this research is to check the validity of a universal management model in the production strategy in the Spanish ceramic tile industry. The work focuses on infrastructure decisions, and seeks to highlight the effect of internal and external resources on the competitive advantage of the area of production of the industry. The data used were collected from 76 Spanish tile manufacturers companies and the results show that in this sector the resources that have been implanted have little association to the manufacturing priorities. In addition, it is shown that the competitive advantage is better explained by the internal learning variables than by the manufacturing practices.

  13. Development of the microstructure of the silicon nitride based ceramics

    Directory of Open Access Journals (Sweden)

    Bressiani J.C.

    1999-01-01

    Full Text Available Basic regularities of silicon nitride based materials microstructure formation and development in interrelation with processing conditions, type of sintering additives, and starting powders properties are discussed. Models of abnormal or exaggerated grain growth are critically reassessed. Results of several model experiments conducted in order to determine the most important factors directing the microstructure formation processes in RE-fluxed Si3N4 ceramics are reviewed. Existing data on the mechanisms governing the microstructure development of Si3N4-based ceramics are analyzed and several principles of microstructure tailoring are formulated.

  14. Performance of the Tile PreProcessor Demonstrator for the ATLAS Tile Calorimeter Phase II Upgrade

    International Nuclear Information System (INIS)

    The Tile Calorimeter PreProcessor demonstrator is a high performance double AMC board based on FPGA resources and QSFP modules. This board has been designed in the framework of the ATLAS Tile Calorimeter Demonstrator project for the Phase II Upgrade as the first stage of the back-end electronics. The TilePPr demonstrator has been conceived to receive and process the data coming from the front-end electronics of the TileCal Demonstrator module, as well as to configure it. Moreover, the TilePPr demonstrator handles the communication with the Detector Control System to monitor and control the front-end electronics. The TilePPr demonstrator represents 1/8 of the final TilePPr that will be designed and installed into the detector for the ATLAS Phase II Upgrade

  15. Performance of the TilePPr demonstrator for the ATLAS Tile Calorimeter Phase II Upgrade

    CERN Document Server

    Carrio Argos, Fernando; The ATLAS collaboration

    2015-01-01

    The Tile Calorimeter Pre-processor (TilePPr) demonstrator is a high performance double AMC board based on FPGA resources and QSFP modules. This board has been designed in the framework of the ATLAS Tile Calorimeter (TileCal) Demonstrator Project for the Phase II Upgrade as the first stage of the off-detector electronics. The TilePPr demonstrator has been conceived for receiving and processing the data coming from the on-detector electronics of the TileCal Demonstrator module, as well as for configuring it. Moreover, the TilePPr demonstrator handles the communication with the Detector Control System to monitor and control the on-detector electronics.

  16. Effect of the drying cycle on dried tile mechanical strength

    Energy Technology Data Exchange (ETDEWEB)

    Amoros, J.L.; Sanchez, E.; Cantavella, V.; Monzo, M.; Jarque, J.C. [Universitat Jaume I, Castellon (Spain). Inst. de Tecnologia Ceramica; Timellini, G. [Centro Ceramico, Bologna (Italy); Leak, N. [British Ceramic Research Association, Stoke-on-Trent (United Kingdom)

    2002-07-01

    The study shows that the industrial ceramic tile drying rate enormously affects dried tile mechanical strength. Tiles dried in an industrial facility were used to determine the variation of dried tile mechanical strength with storage time in a moisture-free container. Dried tile mechanical strength rose with storage time under these conditions. Under the most favourable conditions, dry mechanical strength increased by up to 60% of the starting value. The reason for the rise in mechanical strength is attributed to the relaxation of stresses that develop during fast industrial drying. The effect of the drying cycle on mechanical strength is interpreted on the basis of tile dimensional changes with temperature and moisture content during drying. This assumption was confirmed by laboratory experiments in a dilatometer. (orig.)

  17. Integrated thick-film nanostructures based on spinel ceramics.

    Science.gov (United States)

    Klym, Halyna; Hadzaman, Ivan; Shpotyuk, Oleh; Brunner, Michael

    2014-01-01

    Integrated temperature-humidity-sensitive thick-film structures based on spinel-type semiconducting ceramics of different chemical compositions and magnesium aluminate ceramics were prepared and studied. It is shown that temperature-sensitive thick-film structures possess good electrophysical characteristics in the region from 298 to 358 K. The change of electrical resistance in integrated thick-film structures is 1 order, but these elements are stable in time and can be successfully used for sensor applications. PMID:24670141

  18. High efficiency tantalum-based ceramic composite structures

    Science.gov (United States)

    Stewart, David A. (Inventor); Leiser, Daniel B. (Inventor); DiFiore, Robert R. (Inventor); Katvala, Victor W. (Inventor)

    2010-01-01

    Tantalum-based ceramics are suitable for use in thermal protection systems. These composite structures have high efficiency surfaces (low catalytic efficiency and high emittance), thereby reducing heat flux to a spacecraft during planetary re-entry. These ceramics contain tantalum disilicide, molybdenum disilicide and borosilicate glass. The components are milled, along with a processing aid, then applied to a surface of a porous substrate, such as a fibrous silica or carbon substrate. Following application, the coating is then sintered on the substrate. The composite structure is substantially impervious to hot gas penetration and capable of surviving high heat fluxes at temperatures approaching 3000.degree. F. and above.

  19. Coating Silicon-Based Ceramics With Durable Mullite

    Science.gov (United States)

    Miller, Robert A.; Jacobson, Nathan S.; Lee, Kang N.

    1996-01-01

    Improved plasma-spraying process deposits mullite on silicon carbide substrates. Prevents formation of amorphous mullite by maintaining high temperature of sprayed deposite to allow crystallization to occur. Deposited mullite adheres to substrate and exhibits little or no cracking during thermal cycling. Provides substantially greater resistance to oxidation in dry air and corrosion by molten salt. Process expected useful in depositing mullite on substrates made of other silicon-based ceramics and other ceramic substrates having coefficients of thermal expansion similar to those of mullite.

  20. Effects of using kaolin waste and granite waste as raw materials for the production of low-water absorption ceramic tiles

    International Nuclear Information System (INIS)

    This study aims to evaluate the potential of co-use of granite waste (Rain Forest) and kaolin waste as raw material for the manufacture of ceramic coating of low water absorption. Raw materials were characterized by X-ray diffraction. Kaolin residue was added to the residue of granite in the following proportions (in wt%): 0, 10, 20, 30, 40 and 50%. Specimens were fabricated by uniaxial pressing and fired at 1175,1200 and 1225 deg C. Studies of firing linear shrinkage, water absorption, apparent porosity, apparent density and tensile bending test (or rupture modulus) were conducted. The temperature of 1225 deg C allowed the use of a mixture of 50% granite residue and 50% kaolin residue. Ceramic parts made from that mixture exhibited the maximum values required by the Brazilian Standard NBR 13818 for water absorption, shrinkage and density. (author)

  1. LIMITS IN APPLICATION OF INTERNATIONAL STANDARDS TO INNOVATIVE CERAMIC SOLUTIONS

    Directory of Open Access Journals (Sweden)

    Cristiano Fragassa

    2015-06-01

    Full Text Available Gres Porcelain stoneware is a ceramic with a compact, hard, coloured and non-porous body. It is largely used as building materials, for a quality architecture, offering high resistance to impact, stress, wear, scratching, frost, chemical attach and stains. It is produced in flat tiles, billions of tons per year. A very prominent technology, based on a pyroclastic deformation, permits to obtain bended porcelain tiles as innovative solutions for a modern architecture. This technology is grounded on a proper combination of heavy machining by cutting tools and secondary firing in a kiln. This new element, the bended tile, can be used in several innovative applications (as steps, shelves, benches, radiators.... But, new functions require a better and in-depth knowledge of these materials, especially referring to the mechanical proprieties. This paper investigates the limits of applicability of ISO standards for the quality classification of ceramics and experimental measures of their mechanical proprieties.

  2. Glazed Sludge Tile

    OpenAIRE

    Dayalan J; Beulah. M

    2014-01-01

    In this article, glaze with different colorants was applied to tile specimens manufactured by incinerated sewage sludge ash (ISSA) and Clay. Improvements using different amounts of colorants, and glaze components and concentrations on tile bodies were investigated. Three different proportions of clay (by weight ratio) were replaced by ISSA. Tiles of size 10cm *10cm*1 cm were made and left in an electric furnace to make biscuit tiles at 800°C. Afterwards, four colorants, Fe2O3 ...

  3. Double Handled Brane Tilings

    CERN Document Server

    Cremonesi, Stefano; Seong, Rak-Kyeong

    2013-01-01

    We classify the first few brane tilings on a genus 2 Riemann surface and identify their toric Calabi-Yau moduli spaces. These brane tilings are extensions of tilings on the 2-torus, which represent one of the largest known classes of 4d N=1 superconformal field theories for D3-branes. The classification consists of 16 distinct genus 2 brane tilings with up to 8 quiver fields and 4 superpotential terms. The Higgs mechanism is used to relate the different theories.

  4. Isoperimetric Pentagonal Tilings

    CERN Document Server

    Chung, Ping Ngai; Li, Yifei; Mara, Michael; Morgan, Frank; Plata, Isamar Rosa; Shah, Niralee; Vieira, Luis Sordo; Wikner, Elena

    2011-01-01

    We identify least-perimeter unit-area tilings of the plane by convex pentagons, namely tilings by Cairo and Prismatic pentagons, find infinitely many, and prove that they minimize perimeter among tilings by convex polygons with at most five sides.

  5. The ATLAS tile calorimeter

    CERN Multimedia

    Maximilien Brice

    2003-01-01

    Louis Rose-Dulcina, a technician from the ATLAS collaboration, works on the ATLAS tile calorimeter. Special manufacturing techniques were developed to mass produce the thousands of elements in this detector. Tile detectors are made in a sandwich-like structure where these scintillator tiles are placed between metal sheets.

  6. Analysis of the impact of ISO 14001 in the economic variables of the Spanish ceramic tile industry's companies; ISO 14001 y variables economicas, hay alguna relacion? Analisis de las empresas certificadas del sector ceramico espanol

    Energy Technology Data Exchange (ETDEWEB)

    Peiro-Signes, A.; Segarra-Ona, M.; Mondejar-Jimenez, J.; Vargas-Vargas, M.

    2013-02-01

    The increased in the adoption of formally environmental certified practices through environmental management systems is a provable fact. Its implementation, which has a high cost for the companies, is expected to generate benefits, although the relation between the implementation of ISO 14001 and its influence on the improvement of economic indicators over time has not been documented. This paper analyzes the relation between the implementation of an environmental management system, the ISO 14001, and economic performance in the short, medium and long term for the companies of the Spanish ceramic tile industry. It explores the economic indicators for each of the 66 manufacturing companies which have implemented the aforementioned standard from 1996 until 2009 through a comparison with a control group. Results show that ISO 14001 does not affect the economic results of the studied companies. We have not found significant differences in the operating income values, neither in the increase in revenues in the long term in any of the three analyzed periods, contrary to the expected results. (Author) 60 refs.

  7. Wastes based glasses and glass-ceramics

    Directory of Open Access Journals (Sweden)

    Barbieri, L.

    2001-12-01

    Full Text Available Actually, the inertization, recovery and valorisation of the wastes coming from municipal and industrial processes are the most important goals from the environmental and economical point of view. An alternative technology capable to overcome the problem of the dishomogeneity of the raw material chemical composition is the vitrification process that is able to increase the homogeneity and the constancy of the chemical composition of the system and to modulate the properties in order to address the reutilization of the waste. Moreover, the glasses obtained subjected to different controlled thermal treatments, can be transformed in semy-cristalline material (named glass-ceramics with improved properties with respect to the parent amorphous materials. In this review the tailoring, preparation and characterization of glasses and glass-ceramics obtained starting from municipal incinerator grate ash, coal and steel fly ashes and glass cullet are described.

    Realmente la inertización, recuperación y valorización de residuos que proceden de los procesos de incineración de residuos municipales y de residuos industriales son metas importantes desde el punto de vista ambiental y económico. Una tecnología alternativa capaz de superar el problema de la heterogeneidad de la composición química de los materiales de partida es el proceso de la vitrificación que es capaz de aumentar la homogeneidad y la constancia de la composición química del sistema y modular las propiedades a fin de la reutilización del residuo. En este artículo se presentan los resultados de vitrificación en que los vidrios fueron sometidos a tratamientos térmicos controlados diferentes, de manera que se transforman en materiales semicristalinos (también denominados vitrocerámicos con mejores propiedades respecto a los materiales amorfos originales. En esta revisión se muestra el diseño, preparación y caracterización de vidrios y vitrocerámicos partiendo de

  8. Optical Ceramics Based on Yttrium Oxide Doped with Tetravalent Ions

    Science.gov (United States)

    Osipov, V. V.; Solomonov, V. I.; Shitov, V. A.; Maksimov, R. N.; Orlov, A. N.; Murzakaev, A. M.

    2015-05-01

    Optical ceramics activated by neodymium or ytterbium and based on Y2O3 with inclusions of CeO2 , ZrO2 , and HfO2 containing optical inhomogeneities in the form of an orange peel are investigated. It is indicated that in the ceramics with such inclusions not only the crystallite size and porosity, but also the transmission near the edge of the fundamental absorption band decrease, and the theoretically predicted transparency is not achieved (even in the infrared range). It is reported that in the ceramics containing Hf 4+ and Zr4+ , Hf 3+ and Zr3+ , additionally depopulating the 4 F 3/2 upper laser level of the Nd3+ ion activator, are also present. The dependences of the Nd:Y2O3 crystal lattice parameter on the Hf 4+ or Nd3+ content in it, constructed based on the results of x-ray diffraction analysis, are linear, that is, no peculiarities are observed for solid solutions of these compounds. Energy dispersion analysis with a resolution of about 1 μm also indicates the uniformity of the distribution of the chemical elements throughout the sample. At the same time, estimates based on the Rayleigh light scattering in the ceramics indicate that one of the additional phases must have sizes smaller than λ/20 = 20 nm. By the method of high-resolution transmission electron microscopy, particles with composition modulated on the nanolevel are detected in the 90(Nd0.01Y0.99)2O3 + 10HfO2 nanopowder from which the ceramics are synthesized given that the lattice period remains unchanged.

  9. Fibonacci words, hyperbolic tilings and grossone

    Science.gov (United States)

    Margenstern, Maurice

    2015-04-01

    In this paper, we study the contribution of the theory of grossone to the study of infinite Fibonacci words, combining this tool with the help of a particular tiling of the hyperbolic plane: the tiling { 7, 3 } , called the heptagrid. With the help of the numeral system based on grossone, we obtain a richer family of infinite Fibonacci words compared with the traditional approach.

  10. Desenvolvimento de massas de revestimento cerâmico com argila caulinítica e nefelina sienito Development of ceramic tile bodies with kaolinitic clay and nepheline-syenite

    Directory of Open Access Journals (Sweden)

    C. M. F. Vieira

    2008-06-01

    Full Text Available Este trabalho tem por objetivo adicionar tanto o fundente nefelina sienito, disponível no Estado do Rio de Janeiro, quanto o talco, fornecido por uma mineradora, em uma argila caulinítica para a obtenção de revestimento cerâmico gresificado. Foram preparadas formulações com 0%, 30% e 50% em peso de nefelina sienito em mistura com a argila, com e sem a adição de 3,5% em peso de talco. O comportamento de queima das formulações foi avaliado por dilatometria óptica. Corpos-de-prova foram obtidos por prensagem uniaxial a 30 MPa para queima a 1175 ºC. Nas amostras queimadas foram realizados ensaios tecnológicos para determinação da densidade aparente, retração linear, resistência mecânica por flexão em três pontos e absorção de água. Análise microestrutural foi feita por microscopia eletrônica de varredura e difração de raios X. Os resultados mostraram que a as formulações com nefelina sienito e talco apresentam potencial para a obtenção de revestimento gresificado, reduzindo significativamente a porosidade da cerâmica argilosa pura.This work had for objective to add both the nepheline-syenite flux, available in the State of Rio de Janeiro, and the talc, purchased from a mining company, into a kaolinitic clay to obtain vitrified ceramic tile. Mixtures were prepared with addition of 0, 30 and 50 wt.% of nepheline-syenite to a kaolinitic clay. The talc was added in the amount of 0 and 3.5 wt.%. The firing behavior of the formulations was evaluated by optical dilatometry. Specimens were prepared by uniaxial pressure at 30 MPa followed by firing at 1175 ºC. The fired specimens were submitted to the following tests: bulk density, linear shrinkage, three point bending mechanical strength and water absorption. Microstructural analysis was carried out by scanning electron microscopy and X-ray diffraction. The results showed that the formulations with both nepheline-syenite and talc addition have a potential to obtain

  11. Structural aspects of tilings

    CERN Document Server

    Ballier, Alexis; Jeandel, Emmanuel

    2008-01-01

    In this paper, we study the structure of the set of tilings produced by any given tile-set. For better understanding this structure, we address the set of finite patterns that each tiling contains. This set of patterns can be analyzed in two different contexts: the first one is combinatorial and the other topological. These two approaches have independent merits and, once combined, provide somehow surprising results. The particular case where the set of produced tilings is countable is deeply investigated while we prove that the uncountable case may have a completely different structure. We introduce a pattern preorder and also make use of Cantor-Bendixson rank. Our first main result is that a tile-set that produces only periodic tilings produces only a finite number of them. Our second main result exhibits a tiling with exactly one vector of periodicity in the countable case.

  12. Thermal Insulating Concrete Tiles

    Directory of Open Access Journals (Sweden)

    Sarkawt.A. Saeed

    2012-11-01

    Full Text Available This Paper studies the shape of high-thermal insulating concrete tiles used for roof tiling. The theoretical part consists of a comparison between this invented tiles and ordinary terrazzo tiles. The analysis depends on the values of thermal conductivity of the material used. The results showed that when these tiles are used for roof tiling, the temperature difference between the outside of roof surface and the inside room can be reduced about six times compared with the use of ordinary terrazzo tiles. In addition, these specimens were fabricated and tested for rupture and absorption tests. The test results showed that, they had a good resistance to the applied test loads, and high resistance to water absorption. The authors believe that, the results are remarkable, highly applicable and should be taken into consideration in building constructions.

  13. The lack of homogeneity in the product (LHP) in the ceramic tile industry and its impact on the reallocation of inventories

    International Nuclear Information System (INIS)

    The allocation of the product available- to-promise (ATP) in make-to-stock (MTS) contexts is of the utmost importance as it can influence customer satisfaction and profits of the company. However, a proper initial allocation may become inadequate for several reasons. In these case, it is necessary the reallocation of inventory, which will be more complex the more ambitious goals to achieve with it and increased the amount of information to use. In this regard, it is noteworthy that the lack of homogeneity in the product (LHP), present in different industrial sectors, causes the atomization of the inventory and increases the complexity of the reallocation, difficult to obtain optimal solutions. This paper describes the problems of the LHP, first under a generic perspective and then, particularized to MTS ceramic companies. Subsequently, situations in which a specific allocation of ATP can no longer be appropriate in this context are identified and the reassignment, as a way to search for new valid assignments, is proposed. Finally, through a case study of a ceramic company, the impact of the LHP in each of the situations identified is analyzed, noting that the LHP causes some of these situations and in all of them, complicates the reallocation of inventory to orders. (Authors) 31 refs.

  14. Neodymium incorporation in zirconolite-based glass-ceramics

    International Nuclear Information System (INIS)

    The investigations on enhanced reprocessing of nuclear spent fuel, and notably on separating the long-lived minor actinides, such as Am and Cm, from the other fission products have led to the development of highly durable specific matrices such as glass-ceramics for their immobilization. This study deals with the characterization of zirconolite (CaZrT2O7) based glass-ceramics synthesized by devitrification of an aluminosilicate parent glass. Trivalent actinide ions were simulated by neodymium, which is a paramagnetic local probe. Glass-ceramics with Nd2O3 contents ranging from 0 to 10 weight % were prepared by heat treatment of a parent glass at two different growth temperatures: 1050 deg and 1200 deg C. X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX) and electron spin resonance (ESR) measurements clearly indicate that Nd3+ ions are partly incorporated in zirconolite crystals formed in the bulk of the glass-ceramic samples. The amount of neodymium in the crystalline phase was estimated using ESR results and was found to decrease with increasing either heat treatment temperature or total Nd2O-3 content. Copyright (2001) Material Research Society

  15. Reliability of metalloceramic and zirconia-based ceramic crowns.

    Science.gov (United States)

    Silva, N R F A; Bonfante, E A; Zavanelli, R A; Thompson, V P; Ferencz, J L; Coelho, P G

    2010-10-01

    Despite the increasing utilization of all-ceramic crown systems, their mechanical performance relative to that of metal ceramic restorations (MCR) has yet to be determined. This investigation tested the hypothesis that MCR present higher reliability over two Y-TZP all-ceramic crown systems under mouth-motion fatigue conditions. A CAD-based tooth preparation with the average dimensions of a mandibular first molar was used as a master die to fabricate all restorations. One 0.5-mm Pd-Ag and two Y-TZP system cores were veneered with 1.5 mm porcelain. Crowns were cemented onto aged (60 days in water) composite (Z100, 3M/ESPE) reproductions of the die. Mouth-motion fatigue was performed, and use level probability Weibull curves were determined. Failure modes of all systems included chipping or fracture of the porcelain veneer initiating at the indentation site. Fatigue was an acceleration factor for all-ceramic systems, but not for the MCR system. The latter presented significantly higher reliability under mouth-motion cyclic mechanical testing. PMID:20660796

  16. 'Age-hardened alloy' based on bulk polycrystalline oxide ceramic

    Science.gov (United States)

    Gurnani, Luv; Singh, Mahesh Kumar; Bhargava, Parag; Mukhopadhyay, Amartya

    2015-05-01

    We report here for the first time the development of 'age-hardened/toughened' ceramic alloy based on MgO in the bulk polycrystalline form. This route allows for the facile development of a 'near-ideal' microstructure characterized by the presence of nanosized and uniformly dispersed second-phase particles (MgFe2O4) within the matrix grains, as well as along the matrix grain boundaries, in a controlled manner. Furthermore, the intragranular second-phase particles are rendered coherent with the matrix (MgO). Development of such microstructural features for two-phase bulk polycrystalline ceramics is extremely challenging following the powder metallurgical route usually adopted for the development of bulk ceramic nanocomposites. Furthermore, unlike for the case of ceramic nanocomposites, the route adopted here does not necessitate the usage of nano-powder, pressure/electric field-assisted sintering techniques and inert/reducing atmosphere. The as-developed bulk polycrystalline MgO-MgFe2O4 alloys possess considerably improved hardness (by ~52%) and indentation toughness (by ~35%), as compared to phase pure MgO.

  17. Investigation on Ballistic Performance of Armor Ceramics against Long-Rod Penetration

    Science.gov (United States)

    Huang, Feng-Lei; Zhang, Lian-Sheng

    2007-12-01

    A series of depth-of-penetration (DOF) tests are carried out to investigate the ballistic performance of armor ceramics. Based on the experimental results, an improved differential efficiency factor (DEF) is presented, which demonstrates that the general ballistic efficiency index is independent of the ceramic thickness. It is also shown that the density, internal friction, and compression strength of ceramics are crucial factors that affect the ballistic performance of ceramics significantly through the interaction between the long-rod projectiles and thick-tile armor.

  18. Glazed Sludge Tile

    Directory of Open Access Journals (Sweden)

    Dayalan J

    2014-03-01

    Full Text Available In this article, glaze with different colorants was applied to tile specimens manufactured by incinerated sewage sludge ash (ISSA and Clay. Improvements using different amounts of colorants, and glaze components and concentrations on tile bodies were investigated. Three different proportions of clay (by weight ratio were replaced by ISSA. Tiles of size 10cm *10cm*1 cm were made and left in an electric furnace to make biscuit tiles at 800°C. Afterwards, four colorants, Fe2O3 (red, V2O5 (yellow, and CoCO3 (blue and three different glaze concentrations were applied on biscuit tile specimens. These specimens were later sintered into glazed tiles at 1050°C. The study shows that replacement of clay by sludge ash had adverse effects on properties of tiles. Water absorption increased and bending strength reduced with increased amounts of sludge ash. However, both water absorption and bending strength improved for glazed ash tiles. Abrasion of grazed tiles reduced noticeably from 0.001 to 0.002 g. This implies glaze can enhance abrasion resistance of tiles.

  19. Engineering of silicon-based ceramic fibers: Novel SiTaC(O) ceramic fibers prepared from polytantalosilane

    International Nuclear Information System (INIS)

    Research highlights: → This paper reports the preparation and characterization of a novel variety of silicon-based ceramic fibers. → In the present paper, we provide a detailed picture of the preparation process of SiTaC(O) ceramic fibers from a polytantalosilane. → We have fully characterized the polymer by FT-IR, NMR, chemical composition, GPC and TGA as well as the chemical composition, the structure, the texture, and the mechanical properties of the ceramic fibers by XPS, SEM, X-ray diffraction (XRD), and mechanical tests. - Abstract: A novel variety of silicon-based ceramic fibers has been prepared from a preceramic organosilicon polymers called polytantalocarbosilane (PTaCS). This melt-spinnable polymer has been synthesized by thermally induced reactions between tantalum (V) tetraethoxyacetylacetonate (Ta(Acac)(OEt)4) and polysilacarbosilane (PSCS). The polymer in which [-Si-C-]n chains are crosslinked via Ta-containing bridges as identified by infrared spectroscopy, XPS and NMR, is decomposed in high ceramic yield (76%) and can be spun in the molten state into fibers to be cured in air then pyrolyzed in flowing nitrogen at 1200 deg. C into amorphous SiTaC(O) fibers. Complete characterization of this new generation of silicon-based ceramic fibers was made based on mechanical tests, XRD and SEM. These fibers exhibit relatively good mechanical properties and excellent high-temperature stability with good oxidation resistance.

  20. Engineering of silicon-based ceramic fibers: Novel SiTaC(O) ceramic fibers prepared from polytantalosilane

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Z., E-mail: xiezhengfang@163.com [State Key Laboratory of Advanced Ceramic Fibers and Composites, National University of Defense Technology, Changsha 410073 (China); Cao, S.; Wang, J. [State Key Laboratory of Advanced Ceramic Fibers and Composites, National University of Defense Technology, Changsha 410073 (China); Yan, X. [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Bernard, S., E-mail: Samuel.Bernard@univ-lyon1.fr [Laboratoire des Multimateriaux et Interfaces (UMR CNRS 5615), Universite de Lyon, Universite Lyon1, 43 bd du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Miele, P. [Laboratoire des Multimateriaux et Interfaces (UMR CNRS 5615), Universite de Lyon, Universite Lyon1, 43 bd du 11 Novembre 1918, 69622 Villeurbanne Cedex (France)

    2010-10-15

    Research highlights: {yields} This paper reports the preparation and characterization of a novel variety of silicon-based ceramic fibers. {yields} In the present paper, we provide a detailed picture of the preparation process of SiTaC(O) ceramic fibers from a polytantalosilane. {yields} We have fully characterized the polymer by FT-IR, NMR, chemical composition, GPC and TGA as well as the chemical composition, the structure, the texture, and the mechanical properties of the ceramic fibers by XPS, SEM, X-ray diffraction (XRD), and mechanical tests. - Abstract: A novel variety of silicon-based ceramic fibers has been prepared from a preceramic organosilicon polymers called polytantalocarbosilane (PTaCS). This melt-spinnable polymer has been synthesized by thermally induced reactions between tantalum (V) tetraethoxyacetylacetonate (Ta(Acac)(OEt){sub 4}) and polysilacarbosilane (PSCS). The polymer in which [-Si-C-]{sub n} chains are crosslinked via Ta-containing bridges as identified by infrared spectroscopy, XPS and NMR, is decomposed in high ceramic yield (76%) and can be spun in the molten state into fibers to be cured in air then pyrolyzed in flowing nitrogen at 1200 deg. C into amorphous SiTaC(O) fibers. Complete characterization of this new generation of silicon-based ceramic fibers was made based on mechanical tests, XRD and SEM. These fibers exhibit relatively good mechanical properties and excellent high-temperature stability with good oxidation resistance.

  1. Development of the microstructure of the silicon nitride based ceramics

    OpenAIRE

    Bressiani J. C.; Izhevskyi V.; Bressiani Ana H. A.

    1999-01-01

    Basic regularities of silicon nitride based materials microstructure formation and development in interrelation with processing conditions, type of sintering additives, and starting powders properties are discussed. Models of abnormal or exaggerated grain growth are critically reassessed. Results of several model experiments conducted in order to determine the most important factors directing the microstructure formation processes in RE-fluxed Si3N4 ceramics are reviewed. Existing data on the...

  2. Calcium phosphate-based ceramic and composite materials for medicine

    International Nuclear Information System (INIS)

    The topical problems in chemistry and technology of materials based on calcium phosphates aimed at both the replacement of damaged bone tissue and its regeneration are discussed. Specific features of the synthesis of nanocrystalline powders and the fabrication of ceramic implants are described. Advances in the development of porous scaffolds from resorbable and osteoconductive calcium phosphates and of hybrid composites that form the basis of bone tissue engineering are considered.

  3. Fracture Behavior of Alumina-based Prismatic Ceramic Composites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The fracture toughness and fracture work of Al2O3/SiC prismatic ceramic composites was evaluated in this paper, which showed the fracture energy was improved greatly. Based on the observation for crack propagation and fracture morphology, the fracture behavior of the prismatic composites was analyzed. In the bending test, the composites displayed a non-catastrophic behavior and a graceful failure with reasonable load-carrying capability.

  4. Development of New Ecological Ceramic Tiles by Recycling of Waste Glass and Ceramic Materials; Incorporacion de residuos derivados de la fabricacion ceramica y del vidrio reciclado en el proceso ceramico integral

    Energy Technology Data Exchange (ETDEWEB)

    Lazaro, C.; Ramon Trilles, V.; Gomez, F.; Allepuz, S.; Fraga, D.; Carda, J. B.

    2012-07-01

    The following research work shows the results of the introduction of waste generated by the ceramic industry, such as the calcined clay from fired porcelain of stoneware and raw biscuit, sludge and cleaning water, as well as waste from other sectors like the recycling glass. In this way, it can be obtained a stoneware porcelain slab, engobe-glaze and satin glaze that contains high percentage of recyclable raw materials. (Author)

  5. DOP Test Evaluation of the Ballistic Performance of Armor Ceramics against Long Rod Penetration

    Science.gov (United States)

    Huang, Fenglei; Zhang, Liansheng

    2006-07-01

    A series of DOP tests with lateral confinement have been carried out and a linear relation between the residual penetration in RHA and the alumina thickness has been obtained. The rod configuration and the initial transient impact are the two factors that cause the gradual decrease of the differential efficiency factor (DEF) when the ceramic thickness is increased in literature. A new improved DEF definition is proposed to characterize the thick tile ceramic ballistic performance based on a more physical analysis.

  6. Consumo de gás natural na indústria de revestimentos cerâmicos brasileira Consumption of natural gas in Brazilian ceramic tile industry

    Directory of Open Access Journals (Sweden)

    H. J. Alves

    2008-09-01

    Full Text Available O gás natural, atualmente, é a principal fonte de geração de energia térmica utilizada pelas indústrias de revestimentos cerâmicos no mundo e também é um dos itens que tem maior participação sobre o custo do produto acabado. Neste trabalho é apresentado um levantamento do consumo de gás natural realizado em uma indústria de via seca do pólo produtivo de Santa Gertrudes - SP, de modo que foi possível determinar o consumo específico de cada equipamento consumidor, bem como, identificar os "gargalos energéticos" do processo produtivo.The natural gas is the main source of thermic energy generation used by ceramic covering industries around the world and it is also one of the itens which has the biggest weight over the finished product. In this work, it is presented a survey of the consumption of natural gas done in a factory of the productive pole of Santa Gertrudes-SP, which processes its products through a dry way, so that it was possible to determine the specific consumption of each consumer equipment, and also identify the "energetic necks" presented by the same.

  7. Ceramic electrodes based on Magneli phases of titanium oxides

    Directory of Open Access Journals (Sweden)

    Gusev A.A.

    2007-01-01

    Full Text Available Monophase and polyphase ceramic materials based on Magneli phases of titanium oxides of composition Ti3O5, Ti4O7, Ti5O9, and Ti6O11 were synthesized. The materials were obtained by mechanical activation of rutile with titanium and additives of niobium, vanadium, and iron, with subsequent sintering both in reductive atmosphere (hydrogen and in neutral atmosphere (argon in the temperature interval of 1060-1080°C. The dependences of the potentials of the obtained ceramic samples on time and composition during anodic polarization at current density of 5A/dm2 in a 1M solution of sulfuric acid were investigated. We developed a technique for manufacturing anodes in the form of hollow cylinders 60 mm in diameter with a wall 5 mm thick, and flat discs more than 60 mm in diameter.

  8. Colloidal processing of Fe-based metal ceramic composites with high content of ceramic reinforcement

    International Nuclear Information System (INIS)

    Major difficulties of processing metal-matrix composites by means of conventional powder metallurgy techniques are the lack of dispersion of the phases within the final microstructure. In this work, processing through colloidal techniques of the Fe-based metal-matrix composites, with a high content of a ceramic reinforcement (Ti(C,N) ), is presented for the first time in the literature. The colloidal approach allows a higher control of the powders packing and a better homogenization of phases since powders are mixed in a liquid medium. The chemical stability of Fe in aqueous medium determines the dispersion conditions of the mixture. The Fe slurries were formulated by optimising their zeta potential and their rheology, in order to shape bulk pieces by slip-casting. Preliminary results demonstrate the viability of this procedure, also opening new paths to the microstructural design of fully sintered Fe-based hard metal, with 50 vol. % of Ti(C,N) in its composition. (Author)

  9. Rapid hologram generation utilizing layer-based approach and graphic rendering for realistic three-dimensional image reconstruction by angular tiling

    Science.gov (United States)

    Chen, Jhen-Si; Chu, Daping; Smithwick, Quinn

    2014-03-01

    An approach of rapid hologram generation for the realistic three-dimensional (3-D) image reconstruction based on the angular tiling concept is proposed, using a new graphic rendering approach integrated with a previously developed layer-based method for hologram calculation. A 3-D object is simplified as layered cross-sectional images perpendicular to a chosen viewing direction, and our graphics rendering approach allows the incorporation of clear depth cues, occlusion, and shading in the generated holograms for angular tiling. The combination of these techniques together with parallel computing reduces the computation time of a single-view hologram for a 3-D image of extended graphics array resolution to 176 ms using a single consumer graphics processing unit card.

  10. Environmental Barrier Coatings for Silicon-Based Ceramics

    Science.gov (United States)

    Lee, Kang N.; Fox, Dennis S.; Robinson, Raymond C.; Bansal, Narottam P.

    2001-01-01

    Silicon-based ceramics, such as SiC fiber-reinforced SiC (SiC/SiC ceramic matrix composites (CMC) and monolithic silicon nitride (Si3N4), are prime candidates for hot section structural components of next generation gas turbine engines. Silicon-based ceramics, however, suffer from rapid surface recession in combustion environments due to volatilization of the silica scale via reaction with water vapor, a major product of combustion. Therefore, application of silicon-based ceramic components in the hot section of advanced gas turbine engines requires development of a reliable method to protect the ceramic from environmental attack. An external environmental barrier coating (EBC) is considered a logical approach to achieve protection and CP long-term stability. The first generation EBC consisted of two layers, mullite (3Al2O3-2SiO2) bond coat and yttria-stabilized zirconia (YSZ, ZrO2-8 Wt.% Y2O3) top coat. Second generation EBCs, with substantially improved performance compared with the first generation EBC, were developed in the NASA High Speed Research-Enabling Propulsion Materials (HSR-EPM) Program. The first generation EBC consisted of two layers, mullite (3Al2O3-2SiO2) bond coat and yttria-stabilized zirconia (YSZ, ZrO2-8 wt.% Y2O3) top coat. Second generation EBCs, with substantially improved performance compared with the first generation EBC, were developed in the NASA High Speed Research-Enabling Propulsion Materials (HSR-EPM) Program (5). They consist of three layers, a silicon first bond coat, a mullite or a mullite + BSAS (BaO(1-x)-SrO(x)-Al2O3-2SiO2) second bond coat, and a BSAS top coat. The EPM EBCs were applied on SiC/SiC CMC combustor liners in three Solar Turbines (San Diego, CA) Centaur 50s gas turbine engines. The combined operation of the three engines has accumulated over 24,000 hours without failure (approximately 1,250 C maximum combustor liner temperature), with the engine in Texaco, Bakersfield, CA, accumulating about 14,000 hours. As the

  11. INTELLIGENT MATERIALS BASED ON CERAMIC COMPOSITES

    OpenAIRE

    Maximov, Y.; Merzlikin, V.; Sidorov, O.; Suttugin, V.

    2010-01-01

    The paper examines the possibility to design intellectual materials based on film composites. Ferroelectric composites are offered to use as the film composites. The authors discuss ferroelectric composites of different structures. Sensors and intellectual materials on the basis of the obtained composites are considered.

  12. Ceramic Technology Project data base: September 1992 summary report

    Energy Technology Data Exchange (ETDEWEB)

    Keyes, B.L.P.

    1993-06-01

    Data presented in this report represent an intense effort to improve processing methods, testing methods, and general mechanical properties (rupture modulus, tensile, creep, stress-rupture, dynamic and cyclic fatigue, fracture toughness) of candidate ceramics for use in advanced heat engines. This work was performed by many facilities and represents only a small part of the data generated by the Ceramic Technology Project (CTP) since 1986. Materials discussed include GTE PY6, GN-10, NT-154, NT-164, SN-260, SN-251, SN-252, AY6, silicon nitride combined with rare-earth oxides, Y-TZP, ZTA, NC-433, NT-230, Hexoloy SA, MgO-PSZ-to-MgO-PSZ joints, MgO-PSZ-to-cast iron, and a few whisker/fiber-reinforced ceramics. Information in this report was taken from the project`s semiannual and bimonthly progress reports and from final reports summarizing the results of individual studies. Test results are presented in tabular form and in graphs. All data, including test rig descriptions and material characterizations, are stored in the CTP data base and are available to all project participants on request. The objective of this report is to make available the test results from these studies but not to draw conclusions from those data.

  13. Natural radioactivity in zirconia-based dental ceramics

    International Nuclear Information System (INIS)

    Zirconia-based ceramics are being increasingly used in dental prosthetics in substitution of metal cores, which are known to induce local toxic reactions and delayed allergic responses in the oral tissues. Some concerns have been however raised about the use of zirconia, since it is known that unpurified zirconia materials may contain non negligible levels of natural radionuclides of the U/Th series. Combined measurements of alpha and gamma spectrometry as well as beta dosimetry were conducted on zirconia samples used for dental applications. Samples were available in form of powder and/or solid blocks. The results showed that the beta dose rate in zirconia ceramics was on average only slightly higher than the levels measured in natural teeth, and generally lower than the values measured in feldspatic and glass ceramics. These materials are indeed known to deliver a beta dose significantly higher than that measured from natural teeth, due to the relatively high levels of 40K (between 2 and 3 kBq.kg-1). The content of radionuclides of the U/Th series in the zirconia sample was estimated to be lower than 15 Bq.kg-1, i.e. doubtlessly below the exclusion level of 1 kBq.kg-1 recommended by IAEA in the Safety Standard Series. Beta dosimetry measurements, however, gave indications of possible inhomogeneous clusters of radioactivity, which might give rise to local doses above the background. (author)

  14. Natural radioactivity in zirconia-based dental ceramics

    International Nuclear Information System (INIS)

    Zirconia-based ceramics are being increasingly used in dental prosthetics in substitution of metal cores, which are known to induce local toxic reactions and delayed allergic responses in the oral tissues. Some concerns have been however raised about the use of zirconia, since it is known that unpurified zirconia materials may contain non negligible levels of natural radionuclides of the U/Th series. Combined measurements of alpha and gamma spectrometry as well as beta dosimetry were conducted on zirconia samples used for dental applications. Samples were available in form of powder and/or solid blocks. The results showed that the beta dose rate in zirconia ceramics was on average only slightly higher than the levels measured in natural teeth, and generally lower than the values measured in feldspatic and glass ceramics. These materials are indeed known to deliver a beta dose significantly higher than that measured from natural teeth, due to the relatively high levels of 40K (between 2 and 3 kBq·kg-1). The content of radionuclides of the U/Th series in the zirconia sample was estimated to be lower than 15 Bq·kg-1, i.e. doubtlessly below the exclusion level of 1 kBq·kg-1 recommended by IAEA in the Safety Standard Series. Beta dosimetry measurements, however, gave indications of possible inhomogeneous clusters of radioactivity, which might give rise to local doses above the background. (author)

  15. Separators - Technology review: Ceramic based separators for secondary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Nestler, Tina; Schmid, Robert; Münchgesang, Wolfram; Bazhenov, Vasilii; Meyer, Dirk C. [Technische Universität Bergakademie Freiberg, Institut für Experimentelle Physik, Leipziger Str. 23, 09596 Freiberg (Germany); Schilm, Jochen [Fraunhofer-Institut für Keramische Technologien und Systeme IKTS, Winterbergstraße 28, 01277 Dresden (Germany); Leisegang, Tilmann [Fraunhofer-Technologiezentrum Halbleitermaterialien THM, Am St.-Niclas-Schacht 13, 09599 Freiberg (Germany)

    2014-06-16

    Besides a continuous increase of the worldwide use of electricity, the electric energy storage technology market is a growing sector. At the latest since the German energy transition ('Energiewende') was announced, technological solutions for the storage of renewable energy have been intensively studied. Storage technologies in various forms are commercially available. A widespread technology is the electrochemical cell. Here the cost per kWh, e. g. determined by energy density, production process and cycle life, is of main interest. Commonly, an electrochemical cell consists of an anode and a cathode that are separated by an ion permeable or ion conductive membrane - the separator - as one of the main components. Many applications use polymeric separators whose pores are filled with liquid electrolyte, providing high power densities. However, problems arise from different failure mechanisms during cell operation, which can affect the integrity and functionality of these separators. In the case of excessive heating or mechanical damage, the polymeric separators become an incalculable security risk. Furthermore, the growth of metallic dendrites between the electrodes leads to unwanted short circuits. In order to minimize these risks, temperature stable and non-flammable ceramic particles can be added, forming so-called composite separators. Full ceramic separators, in turn, are currently commercially used only for high-temperature operation systems, due to their comparably low ion conductivity at room temperature. However, as security and lifetime demands increase, these materials turn into focus also for future room temperature applications. Hence, growing research effort is being spent on the improvement of the ion conductivity of these ceramic solid electrolyte materials, acting as separator and electrolyte at the same time. Starting with a short overview of available separator technologies and the separator market, this review focuses on ceramic-based

  16. Separators - Technology review: Ceramic based separators for secondary batteries

    International Nuclear Information System (INIS)

    Besides a continuous increase of the worldwide use of electricity, the electric energy storage technology market is a growing sector. At the latest since the German energy transition ('Energiewende') was announced, technological solutions for the storage of renewable energy have been intensively studied. Storage technologies in various forms are commercially available. A widespread technology is the electrochemical cell. Here the cost per kWh, e. g. determined by energy density, production process and cycle life, is of main interest. Commonly, an electrochemical cell consists of an anode and a cathode that are separated by an ion permeable or ion conductive membrane - the separator - as one of the main components. Many applications use polymeric separators whose pores are filled with liquid electrolyte, providing high power densities. However, problems arise from different failure mechanisms during cell operation, which can affect the integrity and functionality of these separators. In the case of excessive heating or mechanical damage, the polymeric separators become an incalculable security risk. Furthermore, the growth of metallic dendrites between the electrodes leads to unwanted short circuits. In order to minimize these risks, temperature stable and non-flammable ceramic particles can be added, forming so-called composite separators. Full ceramic separators, in turn, are currently commercially used only for high-temperature operation systems, due to their comparably low ion conductivity at room temperature. However, as security and lifetime demands increase, these materials turn into focus also for future room temperature applications. Hence, growing research effort is being spent on the improvement of the ion conductivity of these ceramic solid electrolyte materials, acting as separator and electrolyte at the same time. Starting with a short overview of available separator technologies and the separator market, this review focuses on ceramic-based separators

  17. Convex Polygons for Aperiodic Tiling

    OpenAIRE

    Sugimoto, Teruhisa

    2016-01-01

    If all tiles in a tiling are congruent, the tiling is called monohedral. Tiling by convex polygons is called edge-to-edge if any two convex polygons are either disjoint or share one vertex or one entire edge in common. We find that a convex polygon that can generate an edge-to-edge monohedral tiling must be able to generate a periodic tiling.

  18. Use of high-thermal conductive aluminum nitride based ceramics in vacuum UHF electronic devices

    Directory of Open Access Journals (Sweden)

    Chasnyk V. I.

    2013-06-01

    Full Text Available Analysis of properties and characteristics of the alumina, beryllium oxide and aluminum nitride based ceramic materials used in UHF electronic devices has been made. It was shown that the complex of parameters including structural and functional characteristics of the high-thermal conductive aluminum nitride ceramics prevail over all types of alumina ceramics and is not lower than the same characteristics of the beryllium oxide ceramics especially at the temperatures higher than 450 °C. The examples of the prevailing use of the aluminum nitride ceramics inside vacuum UHF-region devices: TWT’s and klystrons.

  19. Influence of clay mineralogy on clay based ceramic products

    International Nuclear Information System (INIS)

    Clay-based ceramic products can either be produced directly from a suitable clay source without the need further addition or such products can be produced from a ceramic body formulated by additions of other raw materials such as feldspar and silica sand. In either case, the mineralogical make-up of the clay component plays a dominating role in the fabrication and properties of the ceramic product. This study was sparked off by a peculiar result observed in one of five local ball clay samples that were used to reformulate a ceramic body. Initial characterisation tests conducted on the clays indicated that these clays can be classified as kaolinitic. However, one of these clays produced a ceramic body that is distinctively different in terms of whiteness, smoothness and density as compared to the other four clays. Careful re-examination of other characterisation data, such as particle size distribution and chemical analysis, failed to offer any plausible explanation. Consequently, the mineralogical analysis by x-ray diffraction was repeated by paying meticulous attention to specimen preparation. Diffraction data for the clay with anomalous behaviour indicated the presence of a ∼ 10A peak that diminished when the same specimen was re-tested after heating in an oven at 12O degree C whilst the other four clays only exhibit the characteristic kaolinite (Al sub 2 O sub 3. 2SiO sub 2. 2H sub 2 0) and muscovite peaks at ∼ 7A and ∼ 10A before and after heat treatment. This suggests the presence of the mineral halloysite (A1 sub 2 0 sub 3. 2SiO sub 2.4H sub 2 0) in that particular clay. This difference in mineralogy can be attributed to account for the variations in physical properties of the final product. Consequently, this paper reviews in general the precautionary measures that must be adhered to during any mineralogical investigation of clay minerals or clay-based materials. The common pitfalls during specimen preparation, machine settings and interpretation of

  20. Hard Tiling Problems with Simple Tiles

    OpenAIRE

    Moore, Cristopher; Robson, John Michael

    2000-01-01

    It is well-known that the question of whether a given finite region can be tiled with a given set of tiles is NP-complete. We show that the same is true for the right tromino and square tetromino on the square lattice, or for the right tromino alone. In the process, we show that Monotone 1-in-3 Satisfiability is NP-complete for planar cubic graphs. In higher dimensions, we show NP-completeness for the domino and straight tromino for general regions on the cubic lattice, and for simply-connect...

  1. 2011 Las Conchas Post Fire Tile Index

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data set consists of an orthophotography tile index based on multi-spectral (red, green, blue, near-infrared) digital aerial imagery, collected and processed...

  2. GIBS Web Map Tile Service (WMTS)

    Data.gov (United States)

    National Aeronautics and Space Administration — The WMTS implementation standard provides a standards-based solution for serviing digital maps using predefined image tiles. Through the constructs of the...

  3. Introductory Tiling Theory for Computer Graphics

    CERN Document Server

    Kaplan, Craig

    2009-01-01

    Tiling theory is an elegant branch of mathematics that has applications in several areas of computer science. The most immediate application area is graphics, where tiling theory has been used in the contexts of texture generation, sampling theory, remeshing, and of course the generation of decorative patterns. The combination of a solid theoretical base (complete with tantalizing open problems), practical algorithmic techniques, and exciting applications make tiling theory a worthwhile area of study for practitioners and students in computer science. This synthesis lecture introduces the math

  4. Ceramic-based fuel technologies: scope and status

    Energy Technology Data Exchange (ETDEWEB)

    Mcclellan, Kenneth J [Los Alamos National Laboratory

    2010-12-16

    This presentation is an overview of the approach, status and path forward for ongoing tasks under the ceramic fuel development part of the program. Experimental work is focused on fundamental studies employing depleted urania-based compositions and mixed oxide (MOX) and minor actinide-bearing MOX. Contributions are included from researchers at LANL, ORNL and BNL. The audience for this presentation consists of the various participants in the FCRD program. Those participants include representatives from: DOE-NE, other national laboratories, DOE funded university researchers, DOE funded industry teams, FCRD funded advisors, and occasionally NRC.

  5. Design of LTCC-based Ceramic Structure for Chemical Microreactor

    OpenAIRE

    D. Belavic; Hrovat, M.; G. Dolanc; Santo Zarnik, M.; Holc, J.; Makarovic, K.

    2012-01-01

    The design of ceramic chemical microreactor for the production of hydrogen needed in portable polymer-electrolyte membrane (PEM) fuel cells is presented. The microreactor was developed for the steam reforming of liquid fuels with water into hydrogen. The complex three-dimensional ceramic structure of the microreactor includes evaporator(s), mixer(s), reformer and combustor. Low-temperature co-fired ceramic (LTCC) technology was used to fabricate the ceramic structures with buried cavities and...

  6. Fractographic features of glass-ceramic and zirconia-based dental restorations fractured during clinical function

    OpenAIRE

    Øilo, Marit; Hardang, Anne Dybdahl; Ulsund, Amanda Hembre; Gjerdet, Nils Roar

    2014-01-01

    Fractures during clinical function have been reported as the major concern associated with all-ceramic dental restorations. The aim of this study was to analyze the fracture features of glass-ceramic and zirconia-based restorations fractured during clinical use. Twenty-seven crowns and onlays were supplied by dentists and dental technicians with information about type of cement and time in function, if available. Fourteen lithium disilicate glass-ceramic restorations and 13 zirconia-based res...

  7. The design of mosaic armour: The influence of tile size on ballistic performance

    OpenAIRE

    Hazell, P.J.; Roberson, C. J.; Moutinho, M.

    2008-01-01

    Silicon carbide square tiles of different areal geometries and manufactured via two different processing routes have been bonded to polycarbonate layers to evaluate their ballistic performance. Four ceramic tile sizes were tested: 85 mm, 60 mm, 50 mm and 33 mm. In each case the residual depth-of-penetration into a polycarbonate semi-infinite backing was recorded. To elucidate the penetration and failure mechanisms, a computational model using the JH-1 ceramic model [Holmquis...

  8. Tiles with no spectra

    OpenAIRE

    Kolountzakis, Mihail N.; Matolcsi, Mate

    2004-01-01

    We exhibit a subset of a finite Abelian group, which tiles the group by translation, and such that its tiling complements do not have a common spectrum (orthogonal basis for their $L^2$ space consisting of group characters). This disproves the Universal Spectrum Conjecture of Lagarias and Wang. Further, we construct a set in some finite Abelian group, which tiles the group but has no spectrum. We extend this last example to the groups $\\ZZ^d$ and $\\RR^d$ (for $d \\ge 5$) thus disproving one di...

  9. Cytotoxic evaluation of silicon nitride-based ceramics

    International Nuclear Information System (INIS)

    Silicon nitride-based ceramics are potential candidates as materials for orthopedic implants due to their chemical stability associated with suitable fracture toughness and propitious tribologic characteristics. Therefore, in this work, dense silicon nitride components are investigated considering their suitability as biomaterials. Initially, two different compositions of silicon nitride were considered, using ytterbium, yttrium and aluminum oxides as sintering aids. The materials were sintered in a carbon resistance furnace under nitrogen atmosphere and were analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) in order to characterize the microstructure. Indentation method was applied in order to obtain hardness and fracture toughness measurements, and in vitro test of cytotoxicity was performed for a preliminary biological evaluation. A microstructure composed of grains of beta-silicon nitride distributed in a secondary phase was observed. The samples achieved fracture toughness values of 5 MPa m1/2 and Vickers hardness values of 13 GPa. Since a nontoxic behavior has been observed during the cytotoxicity tests with the samples, this finding suggests that silicon nitride-based ceramic can be used as a material for clinical applications

  10. Triangle Tiling II: Nonexistence theorems

    OpenAIRE

    Beeson, Michael

    2012-01-01

    An N -tiling of triangle ABC by triangle T is a way of writing ABC as a union of N triangles congruent to T, overlapping only at their boundaries. The triangle T is the "tile". The tile may or may not be similar to ABC . We wish to understand possible tilings by completely characterizing the triples (ABC, T, N) such that ABC can be N -tiled by T. In particular, this understanding should enable us to specify for which N there exists a tile T and a triangle ABC that is N-tiled by T; or given N,...

  11. Compacidade do suporte cerâmico cru versus propriedades do revestimento cerâmico cozido Compactness of the raw artifacts versus the proprieties of sintered ceramic tiles

    Directory of Open Access Journals (Sweden)

    Ana Candida de Almeida Prado

    2012-03-01

    Full Text Available A compacidade é definida como a razão entre a densidade a seco e a densidade real, propriedade importante no processo cerâmico, pois, quanto maior a compacidade, menor é a necessidade de fechamento dos poros durante a sinterização. Os principais fatores que influenciam a compacidade são: distribuição granulométrica das partículas, tamanho e formato do grânulo, preenchimento do molde, pressão e umidade de prensagem. Com o objetivo de variar a compacidade de corpos de prova compostos, primordialmente, por argilas vermelhas da Formação Corumbataí da região de Rio Claro (SP - Brasil, foram aplicadas diferentes pressões durante a confecção de peças. Foram determinadas as propriedades físicas (absorção de água, retração linear, porosidades aberta, fechada e total, densidade aparente e módulo de ruptura à flexão das referidas peças. Conclui-se que, para essas massas compostas por argilas illíticas, albita e teores relativamente elevados de hematita (± 4,5%, quanto maior é a compacidade, menor é a temperatura de queima, para se obterem produtos com um determinado padrão de absorção de água, sendo que as compacidades entre 0,66 e 0,69 apresentaram menor risco de atingir a superqueima.Compactness is the ratio between the dry and real density of the ceramic artifact. This is an important property in the ceramic process, since the greater the compactness, the less need for pore closure in the sinter stage. The main factors that influence compactness are: particle size distribution, granule size and shape, mold filling method, humidity, and compacting pressure. The compacting pressure was modified in order to vary the compactness of the samples, which consisted primarily of red clay from the Rio Claro (SP-Brazil region in the sedimentary deposit of the Corumbataí Formation. To understand the initial compacting influence, the physical properties of water absorption, linear shrinkage, open porosity, closed porosity

  12. Novel fabrication of silicon carbide based ceramics for nuclear applications

    Science.gov (United States)

    Singh, Abhishek Kumar

    Advances in nuclear reactor technology and the use of gas-cooled fast reactors require the development of new materials that can operate at the higher temperatures expected in these systems. These materials include refractory alloys based on Nb, Zr, Ta, Mo, W, and Re; ceramics and composites such as SiC--SiCf; carbon--carbon composites; and advanced coatings. Besides the ability to handle higher expected temperatures, effective heat transfer between reactor components is necessary for improved efficiency. Improving thermal conductivity of the fuel can lower the center-line temperature and, thereby, enhance power production capabilities and reduce the risk of premature fuel pellet failure. Crystalline silicon carbide has superior characteristics as a structural material from the viewpoint of its thermal and mechanical properties, thermal shock resistance, chemical stability, and low radioactivation. Therefore, there have been many efforts to develop SiC based composites in various forms for use in advanced energy systems. In recent years, with the development of high yield preceramic precursors, the polymer infiltration and pyrolysis (PIP) method has aroused interest for the fabrication of ceramic based materials, for various applications ranging from disc brakes to nuclear reactor fuels. The pyrolysis of preceramic polymers allow new types of ceramic materials to be processed at relatively low temperatures. The raw materials are element-organic polymers whose composition and architecture can be tailored and varied. The primary focus of this study is to use a pyrolysis based process to fabricate a host of novel silicon carbide-metal carbide or oxide composites, and to synthesize new materials based on mixed-metal silicocarbides that cannot be processed using conventional techniques. Allylhydridopolycarbosilane (AHPCS), which is an organometal polymer, was used as the precursor for silicon carbide. Inert gas pyrolysis of AHPCS produces near-stoichiometric amorphous

  13. Gesture-Based, Touch-Free Multi-User Gaming on Wall-Sized, High-Resolution Tiled Displays

    OpenAIRE

    Stødle, Daniel; Hagen, Tor-Magne Stien; Bjørndalen, John Markus; Anshus, Otto J.

    2008-01-01

    Having to carry input devices can be inconvenient when interacting with wall-sized, high-resolution tiled displays. Such displays are typically driven by a cluster of computers. Running existing games on a cluster is non-trivial, and the performance attained using software solutions like Chromium is not good enough. This paper presents a touch-free, multi-user, humancomputer interface for wall-sized displays that enables completely device-free interaction. The interfac...

  14. Voronoi spiral tilings

    Science.gov (United States)

    Yamagishi, Yoshikazu; Sushida, Takamichi; Hizume, Akio

    2015-04-01

    The parameter set of Voronoi spiral tilings gives a dual of van Iterson's bifurcation diagram for phyllotactic spirals. We study the Voronoi tilings for the Bernoulli spiral site sets, as the simplest spirals in the centric representation with similarity symmetry. Their parameter set is composed of a family of real algebraic curves in the complex plane, with the Farey sequence structure. This naturally extends to the parameter set for multiple tilings, i.e., the tilings of the covering spaces of the punctured plane. We show the denseness of the parameters z = reiθ for quadrilateral Voronoi spiral multiple tilings. The techniques of dynamical systems are applied to the group of similarity symmetry. The parastichy numbers and the distortion of the Voronoi regions depend on the rational approximations of θ/2π. We consider the limit set of the shapes of the quadrilateral tiles by taking the limit as r → 1, with θ fixed. If θ/2π is a quadratic irrational number, then the limit set is a finite set of rectangles. In particular, if θ/2π is linearly equivalent to the golden section, then the limit is the square.

  15. Tile concrete base materials as substitutes for lead shielding installations diagnostic X-ray; Losetas de materiales con base de hormigon como blindajes sustitutivos del plomo en instalaciones de rayos X de diagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Pombar Camean, M.; Pasin, J.; Fuestes-Vazquez, V.; Alonso, E.; Pereira, B.

    2011-07-01

    In this paper we study the damping characteristics in the energy range of medical diagnostic X-ray product X-RAD trade name manufactured by Construction Radiotherapy Techniques (CTRADC) consisting of different composition tile with concrete base, for its characterization as a substitute shielding material lead.

  16. Ceramic based lightweight composites with extreme dynamic strength

    International Nuclear Information System (INIS)

    On the basis of several years experiments in development of high performance technical ceramics and in investigation of hetero-modulus and hetero-viscous materials and ceramic matrix composites the authors successfully developed a new family of ceramic reinforced lightweight composites with extreme dynamic strength. To obtain these lightweight composites first the matrix materials were developed from different sort of sintered ceramics with high porosity and after the prepared items were re-sintered using reactive sintering methods or were impregnated with nanoparticles of Si3N4, SiAlON ceramics or light metal alloys having excellent mechanical strength and properties. Where it was necessary the pores and material structures of ceramic matrix materials anchored excellent wetting for a wide range of metal alloys, so it was possible to develop several types of ceramic reinforced hetero-modulus light metal composites with extreme dynamic strength of different density. In this work the authors present the c-Si3N4 diamond particles reinforced corundum matrix composite shield plate structures and some of the specially developed low density ceramic foams and high porosity ceramic matrix materials for lightweight metallic composites

  17. Long Term Fatigue Behavior of Zirconia Based Dental Ceramics

    Directory of Open Access Journals (Sweden)

    Moustafa N. Aboushelib

    2010-04-01

    Full Text Available This study evaluated the influence of cyclic loading on zirconia bar-shaped specimens after being subjected to three different surface treatments: particle abrasion with either 50 μm or 110 μm alumina and grinding with diamond points, while polished specimens served as a control. Statistical analysis revealed significant reduction (38-67% in flexure strength (P < 0.001 after three million cycles of dynamic loading for all surface treatments. Scanning electron imaging revealed grain boundary thickening, grain pull-out, and micro-cracking as the main structural defects. The results suggest that various surface treatments of zirconia based dental ceramics may significantly influence their long term fatigue resistance in the oral environment.

  18. Advanced Environmental Barrier Coatings Development for Si-Based Ceramics

    Science.gov (United States)

    Zhu, Dong-Ming; Choi, R. Sung; Robinson, Raymond C.; Lee, Kang N.; Bhatt, Ramakrishna T.; Miller, Robert A.

    2005-01-01

    Advanced environmental barrier coating concepts based on multi-component HfO2 (ZrO2) and modified mullite systems are developed for monolithic Si3N4 and SiC/SiC ceramic matrix composite (CMC) applications. Comprehensive testing approaches were established using the water vapor cyclic furnace, high pressure burner rig and laser heat flux steam rig to evaluate the coating water vapor stability, cyclic durability, radiation and erosion resistance under simulated engine environments. Test results demonstrated the feasibility and durability of the environmental barrier coating systems for 2700 to 3000 F monolithic Si3N4 and SiC/SiC CMC component applications. The high-temperature-capable environmental barrier coating systems are being further developed and optimized in collaboration with engine companies for advanced turbine engine applications.

  19. Improved performance of silicon nitride-based high temperature ceramics

    Science.gov (United States)

    Ashbrook, R. L.

    1977-01-01

    Recent progress in the production of Si3N4 based ceramics is reviewed: (1) high temperature strength and toughness of hot pressed Si3N4 were improved by using high purity powder and a stabilized ZrO2 additive, (2) impact resistance of hot pressed Si3N4 was increased by the use of a crushable energy absorbing layer, (3) the oxidation resistance and strength of reaction sintered Si3N4 were increased by impregnating reaction sintered silicon nitride with solutions that oxidize to Al2O3 or ZrO2, (4) beta prime SiA1ON compositions and sintering aids were developed for improved oxidation resistance or improved high temperature strength.

  20. Digital decoration by continuous ink jet system for ceramic products based in water inks

    International Nuclear Information System (INIS)

    A new continuous ink jet system for digital ceramic decoration using water based dispersed ceramic pigment has been developed, that increases drastically the sustainability of the process. During the development of this work, different equipment for any application and the consumables and design tools have been also developed. (Author)

  1. Challenges of Engineering Grain Boundaries in Boron-Based Armor Ceramics

    Science.gov (United States)

    Coleman, Shawn P.; Hernandez-Rivera, Efrain; Behler, Kristopher D.; Synowczynski-Dunn, Jennifer; Tschopp, Mark A.

    2016-06-01

    Boron-based ceramics are appealing for lightweight applications in both vehicle and personnel protection, stemming from their combination of high hardness, high elastic modulus, and low density as compared to other ceramics and metal alloys. However, the performance of these ceramics and ceramic composites is lacking because of their inherent low fracture toughness and reduced strength under high-velocity threats. The objective of the present article is to briefly discuss both the challenges and the state of the art in experimental and computational approaches for engineering grain boundaries in boron-based armor ceramics, focusing mainly on boron carbide (B4C) and boron suboxide (B6O). The experimental challenges involve processing these ceramics at full density while trying to promote microstructure features such as intergranular films to improve toughness during shock. Many of the computational challenges for boron-based ceramics stem from their complex crystal structure which has hitherto complicated the exploration of grain boundaries and interfaces. However, bridging the gaps between experimental and computational studies at multiple scales to engineer grain boundaries in these boron-based ceramics may hold the key to maturing these material systems for lightweight defense applications.

  2. Challenges of Engineering Grain Boundaries in Boron-Based Armor Ceramics

    Science.gov (United States)

    Coleman, Shawn P.; Hernandez-Rivera, Efrain; Behler, Kristopher D.; Synowczynski-Dunn, Jennifer; Tschopp, Mark A.

    2016-03-01

    Boron-based ceramics are appealing for lightweight applications in both vehicle and personnel protection, stemming from their combination of high hardness, high elastic modulus, and low density as compared to other ceramics and metal alloys. However, the performance of these ceramics and ceramic composites is lacking because of their inherent low fracture toughness and reduced strength under high-velocity threats. The objective of the present article is to briefly discuss both the challenges and the state of the art in experimental and computational approaches for engineering grain boundaries in boron-based armor ceramics, focusing mainly on boron carbide (B4C) and boron suboxide (B6O). The experimental challenges involve processing these ceramics at full density while trying to promote microstructure features such as intergranular films to improve toughness during shock. Many of the computational challenges for boron-based ceramics stem from their complex crystal structure which has hitherto complicated the exploration of grain boundaries and interfaces. However, bridging the gaps between experimental and computational studies at multiple scales to engineer grain boundaries in these boron-based ceramics may hold the key to maturing these material systems for lightweight defense applications.

  3. Design of LTCC-based Ceramic Structure for Chemical Microreactor

    Directory of Open Access Journals (Sweden)

    D. Belavic

    2012-04-01

    Full Text Available The design of ceramic chemical microreactor for the production of hydrogen needed in portable polymer-electrolyte membrane (PEM fuel cells is presented. The microreactor was developed for the steam reforming of liquid fuels with water into hydrogen. The complex three-dimensional ceramic structure of the microreactor includes evaporator(s, mixer(s, reformer and combustor. Low-temperature co-fired ceramic (LTCC technology was used to fabricate the ceramic structures with buried cavities and channels, and thick-film technology was used to make electrical heaters, temperature sensors and pressure sensors. The final 3D ceramic structure consists of 45 LTCC tapes. The dimensions of the structure are 75 × 41 × 9 mm3 and the weight is about 73 g.

  4. Additive Manufacturing of SiC Based Ceramics and Ceramic Matrix Composites

    Science.gov (United States)

    Halbig, Michael Charles; Singh, Mrityunjay

    2015-01-01

    Silicon carbide (SiC) ceramics and SiC fiber reinforcedSiC ceramic matrix composites (SiCSiC CMCs) offer high payoff as replacements for metals in turbine engine applications due to their lighter weight, higher temperature capability, and lower cooling requirements. Additive manufacturing approaches can offer game changing technologies for the quick and low cost fabrication of parts with much greater design freedom and geometric complexity. Four approaches for developing these materials are presented. The first two utilize low cost 3D printers. The first uses pre-ceramic pastes developed as feed materials which are converted to SiC after firing. The second uses wood containing filament to print a carbonaceous preform which is infiltrated with a pre-ceramic polymer and converted to SiC. The other two approaches pursue the AM of CMCs. The first is binder jet SiC powder processing in collaboration with rp+m (Rapid Prototyping+Manufacturing). Processing optimization was pursued through SiC powder blending, infiltration with and without SiC nano powder loading, and integration of nanofibers into the powder bed. The second approach was laminated object manufacturing (LOM) in which fiber prepregs and laminates are cut to shape by a laser and stacked to form the desired part. Scanning electron microscopy was conducted on materials from all approaches with select approaches also characterized with XRD, TGA, and bend testing.

  5. Monomer-dimer tatami tilings of square regions

    CERN Document Server

    Erickson, Alejandro

    2011-01-01

    We prove that the number of monomer-dimer tilings of an $n\\times n$ square grid, with $mtiles meet at any point is $m2^m+(m+1)2^{m+1}$, when $m$ and $n$ have the same parity. In addition, we present a new proof of the result that there are $n2^{n-1}$ such tilings with $n$ monomers, which divides the tilings into $n$ classes of size $2^{n-1}$. The sum of these tilings over all monomer counts has the closed form $2^{n-1}(3n-4)+2$ and, curiously, this is equal to the sum of the squares of all parts in all compositions of $n$. We also describe two algorithms and a Gray code ordering for generating the $n2^{n-1}$ tilings with $n$ monomers, which are both based on our new proof.

  6. The ATLAS Tile Calorimeter

    CERN Document Server

    Henriques Correia, Ana Maria

    2015-01-01

    TileCal is the Hadronic calorimeter covering the most central region of the ATLAS experiment at the LHC. It uses iron plates as absorber and plastic scintillating tiles as the active material. Scintillation light produced in the tiles is transmitted by wavelength shifting fibres to photomultiplier tubes (PMTs). The resulting electronic signals from the approximately 10000 PMTs are measured and digitised every 25 ns before being transferred to off-detector data-acquisition systems. This contribution will review in a first part the performances of the calorimeter during run 1, obtained from calibration data, and from studies of the response of particles from collisions. In a second part it will present the solutions being investigated for the ongoing and future upgrades of the calorimeter electronics.

  7. Tratabilidade de solos tropicais contaminados por resíduos da indústria de revestimentos cerâmicos Treatability of tropical soils contaminated by solid wastes from ceramic tile industry

    Directory of Open Access Journals (Sweden)

    Luciana Pena de Oliveira

    2008-03-01

    Full Text Available Este trabalho de pesquisa buscou investigar a eficácia da remoção de chumbo (Pb e zinco (Zn de uma área contaminada pelo depósito inadequado de resíduos de indústrias de revestimentos cerâmicos do pólo de Santa Gertrudes (São Paulo, Brasil, ocorrido há cerca de trinta anos atrás. Foram avaliados três processos de lixiviação: lavagem com ácido sulfúrico concentrado e por soluções de peróxido de hidrogênio a 30% e de ácido clorídrico 0,1 M. Os resultados obtidos mostraram que o tratamento com peróxido de hidrogênio não removeu Pb e Zn; que a lavagem com ácido sulfúrico concentrado promoveu a redução de 50% dos teores de Zn e a solução de ácido clorídrico 0,1 M reduziu os teores de Pb e Zn em 15% e 10%, respectivamente. O teor remanescente de Zn no solo tratado com ácido sulfúrico concentrado foi de 117 mg/kg e os de Pb e Zn no solo lavado com a solução de ácido clorídrico 0,1 M, de 806 mg/kg e 213 mg/kg, respectivamente, valores estes inferiores aos de intervenção estabelecidos pelo órgão de controle ambiental paulista.The aim of this research was to evaluate different leaching processes to the removal of lead (Pb and zinc (Zn from tropical soil contaminated by inappropriate past deposition of wastes from ceramic tile industries of Santa Gertrudes (São Paulo, Brazil. Three soil washing processes were investigated: with concentrated sulphuric acid, with a 30% solution of hydrogen peroxide and with 0.1M solution of hydrochloric acid. The results indicated that the treatment with hydrogen peroxide did not remove Pb and Zn significantly; the washing with concentrated sulphuric acid caused a 50% reduction of Zn contents and the 0.1M solution of hydrochloric acid reduced Pb and Zn contents in 15% and 10%, respectively. The Zn content remaining in the soil processed with concentrated sulphuric acid was 117 mg/kg and the Pb and Zn contents remaining in the soil processed with 0.1M solution of hydrochloric acid

  8. Conceptual Design for a Bulk Tungsten Divertor Tile in JET

    International Nuclear Information System (INIS)

    With ITER on the verge of being build, the ITER-like Wall project (ILW) for JET aims at providing the plasma chamber of the tokamak with an environment of mixed materials which will be relevant to the support of decisions to the first wall construction and, from the point of view of plasma physics, to the corresponding investigations of possible plasma configuration and plasma-wall interaction. In both respects, tungsten plays a key role in the divertor cladding whereas beryllium will be used for the vessel's first wall. For the central tile, also called LB-SRP for '' Load-Bearing Septum Replacement Plate '', resort to bulk tungsten is envisaged in order to cope with the high loads expected (up to 10 MW/m2 for about 10 s). This is indeed the preferred plasma-facing component for positioning the outer strike-point in the divertor. Forschungszentrum Juelich has developed a conceptual design for this tile, based on an assembly of tungsten blades or lamellae. It was selected in the frame of an extensive R-and-D study in search of a suitable, inertially cooled component(T. Hirai et al., R-and-D on full tungsten divertor and beryllium wall for JET ITER-like Wall Project: this conference). As reported elsewhere, the design is actually driven by electromagnetic considerations in the first place(S. Sadakov et al., Detailed electromagnetic analysis for optimisation of a tungsten divertor plate for JET: this conference). The lamellae are grouped in four stacks per tile which are independently attached to an equally re-designed supporting structure. A so-called adapter plate, also a new design, takes care of an appropriate interface to the base carrier of JET, onto which modules of two tiles are positioned and screwed by remote handling (RH) procedures. The compatibility of the design on the whole with RH requirements is another essential ingredient which was duly taken into account throughout. The concept and the underlying philosophy will be presented along with important

  9. Development of a thin film vitreous bond based composite ceramic coating for corrosion and abrasion services

    International Nuclear Information System (INIS)

    IPC has been involved with the Alberta Research Council in developing a vitreous bond (VB) - based composite ceramic fluoropolymer coating technology. Compared to the present state of the art which is based on a hard discontinuous phase (ceramic particles) suspended in a soft continuous matrix (fluoropolymer mix) the novelty of our approach consists of designing a composite system in which both the ceramic and the fluoropolymer phases are continuous. The ceramic matrix will provide the strength and the erosion resistance for the fluoropolymer matrix even at high temperatures. The ceramic formulation employed is not affected by temperatures up to 500 oF while the fluoropolymer matrix provides a corrosion protection seal for the ceramic matrix. The inherent flexibility of the polymer matrix will protect against brittle fractures that may develop by handling or impact. Therefore the composite coating is able to withstand the deformation of the substrate without chipping or disbanding. The fluoropolymer matrix also provides dry lubrication properties further enhancing the erosion resistance of the ceramic phase. The thickness of the coating is very thin, in the 25 to 100 micron range. In summary, the coating technology is able to provide the following features: Corrosion protection levels similar to those of fluoropolymer coatings; Erosion resistance similar to that of ceramic coatings; Price comparable to that of polymer coatings; Exceptional wear resistance properties; and Capability for coating complicated shapes internally or externally or both. This paper will discuss the theory and development of this new technology and the resultant coating and potential properties. (author)

  10. Fusion tilings with infinite local complexity

    CERN Document Server

    Frank, Natalie Priebe

    2012-01-01

    We extend the formalism of fusion tilings to allow for infinite local complexity. We allow an infinite variety of tile types but require that the space of possible tile types be compact. Examples include solenoids, pinwheel tilings, tilings with fault lines, and tilings with infinitely many tile sizes, shapes, or labels. We examine the invariant measures and define a new notion of complexity that applies to these tilings.

  11. Gesture-Based, Touch-Free Multi-User Gaming on Wall-Sized, High-Resolution Tiled Displays

    Directory of Open Access Journals (Sweden)

    John Markus Bjørndalen

    2008-11-01

    Full Text Available Having to carry input devices can be inconvenient when interacting with wall-sized, high-resolution tiled displays. Such displays are typically driven by a cluster of computers. Running existing games on a cluster is non-trivial, and the performance attained using software solutions like Chromium is not good enough.This paper presents a touch-free, multi-user, human-computer interface for wall-sized displays that enables completely device-free interaction. The interface is built using 16 cameras and a cluster of computers, and is integrated with the games Quake 3 Arena (Q3A and Homeworld. The two games were parallelized using two different approaches in order to run on a 7x4 tile, 21 megapixel display wall with good performance.The touch-free interface enables interaction with a latency of 116 ms, where 81 ms are due to the camera hardware. The rendering performance of the games is compared to their sequential counterparts running on the display wall using Chromium. Parallel Q3A's framerate is an order of magnitude higher compared to using Chromium. The parallel version of Homeworld performed on par with the sequential, which did not run at all using Chromium. Informal use of the touch-free interface indicates that it works better for controlling Q3A than Homeworld.

  12. Preparation and Performance of KNN-based Upconversion Transparent Ceramics

    Directory of Open Access Journals (Sweden)

    GENG Zhi-Ming, LI Kun, SHI Dong-liang, SHI Xia-Yu, HUANG Hai-Tao, CHAN Helen Lai Wa

    2014-12-01

    Full Text Available Upconversion transparent ceramics K0.5(1-yNa0.5(1-yLiyNb1-yBiyO3-Er0.005Yb0.005x(Er3+/Yb3+:KNNLB, x=0-3, y=0-0.09 were fabricated by hot-press sintering process using LiBiO3 as additives. The microstructure, optical transparency and upconversion fluorescence were investigated.The results show that the crystalline phase of the ceramics is orthorhombic-perovskite structure.The ceramics are well densified, and the grain size of the ceramics is about 0.5 μm.These ceramics present good transparency in the infrared and the long-wavelength visible regions, but the optical transparency declines rapidly in the visible region as the amount of Yb3+ and Er3+ ions increases.The transparency of the ceramics with y = 0.06 and x = 0 reaches 45% in the visible region and over 95% in the infrared region(the thickness of the sample is 0.5 mm.The strong upconversion fluorescence is observed when the ceramics are excited by the 900 nm-wavelength light of an xenon lamp.

  13. The effect of ceramic thickness and number of firings on the color of a zirconium oxide based all ceramic system fabricated using CAD/CAM technology

    Science.gov (United States)

    Aras, Meena Ajay

    2011-01-01

    PURPOSE Ceramics have a long history in fixed prosthodontics for achieving optimal esthetics and various materials have been used to improve ceramic core strength. However, there is a lack of information on how color is affected by fabrication procedure. The purpose of this study was to evaluate the effects of various dentin ceramic thicknesses and repeated firings on the color of zirconium oxide all-ceramic system (Lava™) fabricated using CAD/CAM technology. MATERIALS AND METHODS Thirty disc-shaped cores, 12 mm in diameter with a 1 mm thickness were fabricated from zirconium oxide based all ceramic systems (Lava™, 3M ESPE, St Paul, MN, USA) and divided into three groups (n = 10) according to veneering with dentin ceramic thicknesses: as 0.5, 1, or 1.5 mm. Repeated firings (3, 5, 7, or 9) were performed, and the color of the specimens was compared with the color after the initial firing. Color differences among ceramic specimens were measured using a spectrophotometer (VITA Easyshade, VITA Zahnfabrik, Bad Säckingen, Germany) and data were expressed in CIELAB system coordinates. A repeated measures ANOVA and Bonferroni post hoc test were used to analyze the data (n = 10, α=.05). RESULTS L*a*b* values of the ceramic systems were affected by the number of firings (3, 5, 7, or 9 firings) (P<.001) and ceramic thickness (0.5, 1, or 1.5 mm) (P<.001). Significant interactions were present in L*a*b* values between the number of firings and ceramic thickness (P<.001). An increase in number of firings resulted in significant increase in L* values for both 0.5 mm and 1.5 mm thicknesses (P<.01, P=.013); however it decreased for 1 mm thickness (P<.01). The a* values increased for 1 mm and 1.5 mm thicknesses (P<.01), while it decreased for 0.5 mm specimens. The b* values increased significantly for all thicknesses (P<.01, P=.022). As the dentin ceramic thickness increased, significant reductions in L* values (P<.01) were recorded. There were significant increases in both a

  14. Rhythmic canons and modular tiling

    OpenAIRE

    Caure, Hélianthe

    2016-01-01

    This thesis is a contribution to the study of modulo p tiling. Many mathematical and computational tools were used for the study of rhythmic tiling canons. Recent research has mainly focused in finding tiling without inner periodicity, being called Vuza canons. Those canons are a constructive basis for all rhythmic tiling canons, however, they are really difficult to obtain. Best current method is a brut force exploration that, despite a few recent enhancements, is exponential. Many technics ...

  15. Modeling of water absorption induced cracks in resin-based composite supported ceramic layer structures.

    Science.gov (United States)

    Huang, Min; Thompson, V P; Rekow, E D; Soboyejo, W O

    2008-01-01

    Cracking patterns in the top ceramic layers of the modeled dental multilayers with polymer foundation are observed when they are immersed in water. This article developed a model to understand this cracking mechanism. When water diffuses into the polymer foundation of dental restorations, the foundation will expand; as a result, the stress will build up in the top ceramic layer because of the bending and stretching. A finite element model based on this mechanism is built to predict the stress build-up and the slow crack growth in the top ceramic layers during the water absorption. Our simulations show that the stress build-up by this mechanism is high enough to cause the cracking in the top ceramic layers and the cracking patterns predicted by our model are well consistent with those observed in experiments on glass/epoxy/polymer multilayers. The model is then used to discuss the life prediction of different dental ceramics. PMID:17497681

  16. Combinatorial substitutions and sofic tilings

    CERN Document Server

    Fernique, Thomas

    2010-01-01

    A combinatorial substitution is a map over tilings which allows to define sets of tilings with a strong hierarchical structure. In this paper, we show that such sets of tilings are sofic, that is, can be enforced by finitely many local constraints. This extends some similar previous results (Mozes'90, Goodmann-Strauss'98) in a much shorter presentation.

  17. Arithmetic theory of brick tilings

    International Nuclear Information System (INIS)

    A new, 'arithmetic', approach to the algebraic theory of brick tilings is developed. This approach enables one to construct a simple classification of brick tilings in Zd and to find new proofs of several classical results on brick packing and tilings in Zd. In addition, possible generalizations of results on integer brick packing to the Euclidean plane R2 are investigated

  18. Extended DNA Tile Actuators

    DEFF Research Database (Denmark)

    Kristiansen, Martin; Kryger, Mille; Zhang, Zhao;

    2012-01-01

    A dynamic linear DNA tile actuator is expanded to three new structures of higher complexity. The original DNA actuator was constructed from a central roller strand which hybridizes with two piston strands by forming two half-crossover junctions. A linear expansion of the actuator is obtained...

  19. Hardness of resin cement cured under different thickness of lithium disilicate-based ceramic

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xuan; WANG Fu

    2011-01-01

    Background The lithium disilicate-based ceramic is a newly developed all-ceramic material,which is lithium disilicate-based and could be used for fabricating almost all kinds of restorations.The extent of light attenuation by ceramic material was material-dependent.Ceramic materials with different crystal composition or crystalline content would exhibit distinct light-absorbing characteristics.The aim of this study was to analyze the influence of ceramic thickness and light-curing time on the polymerization of a dual-curing resin luting material with a lithium disilicate-based ceramic.Methods A lithium disilicate-based ceramic was used in this study.The light attenuation caused by ceramic with different thickness was determined using a spectral radiometer.The commercial dual-cured resin cement was light-cured directly or through ceramic discs with different thickness (1,2 and 3 mm,respectively) for different times (10,20,30,40,50 and 60 seconds,respectively).The polymerization efficiency of resin cement was expressed in terms as Vickers hardness (VHN) measured after 24 hours storage.Two-way analysis of variance (ANOVA) and Tukey's HSD tests were used to determine differences.Results Intensity of polymerizing light transmitted through ceramic discs was reduced from 584 mW/cm2 to about 216 mW/cm2,80 mW/cm2 and 52 mW/cm2 at thicknesses of 1 mm,2 mm and 3 mm,respectively.Resin cement specimens self-cured alone showed significantly lower hardness values.When resin cement was light-cured through ceramic discs with a thickness of 1 mm,2 mm and 3 mm,no further increasing in hardness values was observed when light-curing time was more than 30 seconds,40 seconds and 60 seconds,respectively.Conclusions Within the limitation of the present study,ceramic thickness and light-curing time had remarkable influence on the polymerization of dual-cured resin cement.When resin cement is light-cured beneath a lithium disilicate ceramic with different thickness,prolonging light

  20. Effect of kaolinitic clays from the State of Rio de Janeiro in the composition of whiteware floor tile bodies Efeito de argilas cauliníticas do Estado do Rio de Janeiro na composição de massa de pavimento cerâmico de base clara

    Directory of Open Access Journals (Sweden)

    C. M. F. Vieira

    2006-06-01

    Full Text Available This work presents an investigation that was undertaken for three types of kaolinitic clays from the State of Rio de Janeiro, Brazil, with a potential use in whiteware floor tiles bodies. Different compositions prepared by mixing the three clays with other materials such as kaolin, quartz, philite, potash feldspar and talc, were investigated and compared with an industrial ceramic body for whiteware floor tiles (group BIIa. Physical and mechanical properties such as linear shrinkage, water absorption and flexural strength were evaluated in pressed specimens fired at temperatures varying from 1025 to 1225 ºC. The microstructure of the specimens was studied by X-ray diffraction, scanning electron microscopy and mercury porosimetry. The results indicated that the prepared compositions presented microstructural characteristics, specially the pore size distribution, and technological properties that are compatible with low-porosity ceramic tiles. However, they also display characteristics, such as an excessive plasticity and high loss on ignition, that could generate problems during the industrial processing.Este trabalho apresenta uma investigação sobre três tipos de argilas cauliníticas do Estado do Rio de Janeiro, Brasil, com potencial uso em massas de pavimentos cerâmicos de base clara. Diferentes composições, preparadas através da mistura das três argilas com outros materiais, tais como quartzo, filito, feldspato potássico e talco, foram investigadas e comparadas com uma massa cerâmica industrial de pavimento de base clara (grupo BIIa. Propriedades físicas e mecânicas tais como retração linear, absorção de água e tensão de ruptura à flexão foram avaliadas em corpos de prova prensados e queimados em temperaturas variando de 1025 a 1225 ºC. A microestrutura das amostras foi avaliada por difração de raios X, microscopia eletrônica de varredura e porosimetria de mercúrio. Os resultados indicaram que as composi

  1. Development of new ceramic materials from the waste of serpentinite and red clay

    International Nuclear Information System (INIS)

    The objective of this work is to develop new ceramic materials using serpentine and glass waste and clay red. The raw materials were characterized through morphological, granulometric, mineralogical and chemical analysis. Six formulations have been developed based on the serpentine and red clay, which three of the six compositions have been adjusted with the addition of residual glass. The ceramic bodies were formed by uniaxial pressing and subjected to burn in an electric oven at temperatures of 1100 ° C, 1200 ° C, 1250 ° C and 1300 ° C. The ceramic samples obtained this way were characterized according to their physical properties (specific mass and linear retraction) and the mechanical (three points bending strength). The final properties varied according to the proportions of raw materials and firing temperature. In general, the different formulations fit the standards for traditional ceramics such as tiles and ceramic blocks. (author)

  2. Magnetoelectric Effect in Ceramics Based on Bismuth Ferrite

    Science.gov (United States)

    Jartych, Elżbieta; Pikula, Tomasz; Kowal, Karol; Dzik, Jolanta; Guzdek, Piotr; Czekaj, Dionizy

    2016-04-01

    Solid-state sintering method was used to prepare ceramic materials based on bismuth ferrite, i.e., (BiFeO3)1 - x -(BaTiO3) x and Bi1 - x Nd x FeO3 solid solutions and the Aurivillius Bi5Ti3FeO15 compound. The structure of the materials was examined using X-ray diffraction, and the Rietveld method was applied to phase analysis and structure refinement. Magnetoelectric coupling was registered in all the materials using dynamic lock-in technique. The highest value of magnetoelectric coupling coefficient α ME was obtained for the Bi5Ti3FeO15 compound ( α ME ~ 10 mVcm-1 Oe-1). In the case of (BiFeO3)1 - x -(BaTiO3) x and Bi1 - x Nd x FeO3 solid solutions, the maximum α ME is of the order of 1 and 2.7 mVcm-1 Oe-1, respectively. The magnitude of magnetoelectric coupling is accompanied with structural transformation in the studied solid solutions. The relatively high magnetoelectric effect in the Aurivillius Bi5Ti3FeO15 compound is surprising, especially since the material is paramagnetic at room temperature. When the materials were subjected to a preliminary electrical poling, the magnitude of the magnetoelectric coupling increased 2-3 times.

  3. Lithium-based oxide ceramics for tritium-breeding applications

    International Nuclear Information System (INIS)

    Material preparation techniques, crystallographic data, phase diagrams, metal compatibility, and thermal properties have been assembled for the lithium-based oxide ceramics designated as potential solid tritium breeders for fusion devices. The materials discussed in this report include: Li2O, β-Li5AlO4, γ-LiAlO2, Li4SiO4, Li2SiO3, Li4TiO4, Li2TiO3, Li8ZrO6, Li4ZrO4, and Li2ZrO3. The thermal properties covered were vaporization, thermal conductivity, specific heat, and linear thermal expansion. There has been no attempt to rank the above mentioned candidates, but rather to merely indicate points that must be considered when using the various materials as solid breeders. These encompass low lithium atom densities, destructive phase transformations, a higher thermal expansion, low thermal conductivity, excessive vaporization at low temperatures, corrosive nature toward metals and difficulty in sample preparation

  4. CREATIVE TILING: A STORY OF 1000-AND-1 CURVES

    Directory of Open Access Journals (Sweden)

    Nasir Al-Darwish

    2012-04-01

    Full Text Available We describe a procedure that utilizes symmetric curves for building artistic tiles. One particular curve was found to mesh nicely with hundreds other curves, resulting in eye-catching tiling designs. The results of our work serve as a good example of using ideas from 2-D graphics and algorithms in a practical web-based application.

  5. Tilings and associated relational structures

    CERN Document Server

    Oger, Francis

    2009-01-01

    In the present paper, as we did previously in [5], we investigate the relations between the geometric properties of tilings and the algebraic and model-theoretic properties of associated relational structures. Our study is motivated by the existence of aperiodic tilings. In [5], we considered tilings of the euclidean spaces of finite dimension, and isomorphism was defined up to translation. Here, we consider, more generally, tilings of a metric space, and isomorphism is defined modulo an arbitrary group of isometries. The results of Sections 1 and 2 concern, in particular, the characterization of relational structures which can be represented by tilings of some given type, local isomorphism and the extraction preorder. In Section 3, we show that the notions of periodicity and invariance through a translation, defined for tilings of the euclidean spaces of finite dimension, can be generalized, with appropriate hypotheses, to relational structures, and in particular to tilings of non-euclidean spaces. In Sectio...

  6. Fractal tiles associated with shift radix systems

    CERN Document Server

    Berthé, Valérie; Steiner, Wolfgang; Surer, Paul; Thuswaldner, Jörg

    2009-01-01

    Shift radix systems form a collection of dynamical systems depending on a parameter $\\mathbf{r}$ which varies in the $d$-dimensional real vector space. They generalize well-known numeration systems such as beta-expansions, expansions with respect to rational bases, and canonical number systems. Beta-numeration and canonical number systems are known to be intimately related to fractal shapes, such as the classical Rauzy fractal and the twin dragon. These fractals turned out to be important for studying properties of expansions in several settings. In the present paper we associate a collection of fractal tiles with shift radix systems. We show that for certain classes of parameters $\\mathbf{r}$ these tiles coincide with affine copies of the well-known tiles associated with beta-expansions and canonical number systems. On the other hand, these tiles provide natural families of tiles for beta-expansions with (non-unit) Pisot numbers as well as canonical number systems with (non-monic) expanding polynomials. We a...

  7. The Mu3e Tile Detector

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, Hans Patrick

    2015-05-06

    The Mu3e experiment is designed to search for the lepton flavour violating decay μ→e{sup +}e{sup +}e{sup -} with a sensitivity of one in 10{sup 16} decays. An observation of such a decay would be a clear sign of physics beyond the Standard Model. Achieving the targeted sensitivity requires a high precision detector with excellent momentum, vertex and time resolution. The Mu3e Tile Detector is a highly granular sub-detector system based on scintillator tiles with Silicon Photomultiplier (SiPM) readout, and aims at measuring the timing of the muon decay products with a resolution of better than 100 ps. This thesis describes the development of the Tile Detector concept and demonstrates the feasibility of the elaborated design. In this context, a comprehensive simulation framework has been developed, in order to study and optimise the detector performance. The central component of this framework is a detailed simulation of the SiPM response. The simulation model has been validated in several measurements and shows good agreement with the data. Furthermore, a 16-channel prototype of a Tile Detector module has been constructed and operated in an electron beam. In the beam tests, a time resolution up to 56 ps has been achieved, which surpasses the design goal. The simulation and measurement results demonstrate the feasibility of the developed Tile Detector design and show that the required detector performance can be achieved.

  8. Strength and corrosion behavior of SiC - based ceramics in hot coal combustion environments

    Energy Technology Data Exchange (ETDEWEB)

    Breder, K.; Parten, R.J. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    As part of an effort to evaluate the use of advanced ceramics in a new generation of coal-fired power plants, four SiC-based ceramics have been exposed to corrosive coal slag in a laboratory furnace and two pilot scale combustors. Initial results indicate that the laboratory experiments are valuable additions to more expensive pilot plant experiments. The results show increased corrosive attack with increased temperature, and that only slight changes in temperature may significantly alter the degree of strength degradation due to corrosive attack. The present results are part of a larger experimental matrix evaluating the behavior of ceramics in the coal combustion environment.

  9. Ceramic materials based on modified pyrogenic titanium dioxide and titanium-silica

    International Nuclear Information System (INIS)

    Ceramic materials based on modified titanium dioxide and titanium-silica are obtained. Method for modification of titanium dioxide and titanium-silica by palladium additions in the process of flame, hydrolysis of titanium, tetrachloride or silicon tetrachloride mixture with titanium tetrachloride is developed. The above method makes it possible to modify already formed particles of the final products in the reactor cooling zone, which does not effect their size and where by the whole palladium is on the surface of the ceramic material. A series of textolite is prepared on the basis of the developed ceramic materials and their metallization is performed

  10. Numerical Study on Anti-Penetration Process of Alumina Ceramic (AD95) to Tungsten Long Rod Projectiles

    Science.gov (United States)

    Zhang, Xianfeng; Zhang, Niansong; Li, Yongchi

    Numerical studies were conducted on the ballistic performance of alumina ceramic (AD95) tiles based on depth of penetration method, when subjected to normal impact of tungsten long rod projectiles at velocities ranging from 1100 to 2000 ms-1. The residual depth on after-effect target was derived in each case, and the ballistic efficiency factor was determined using the corresponding penetration depth on medium carbon steel. Anti-penetration experiment study of the AD95 ceramic tiles to tungsten long rod projectiles has been carried out to verify the accuracy of numerical simulation model. The result shows that numerical simulation results agree well with the corresponding experiment results and AD95 ceramic has excellent ballistic performance than medium carbon steel. The ballistic efficiency factor increases with velocity increasing when impact velocity lower than 1300 ms-1, and when it was higher than 1300 ms-1 the ballistic efficiency factor has almost no difference.

  11. Composite materials based on porous ceramic preform infiltrated by aluminium alloy

    Directory of Open Access Journals (Sweden)

    A. Nagel

    2007-01-01

    Full Text Available Purpose: The goal of this project is the optimization of manufacturing technology of the ceramic preforms basedon Al2O3 powder manufactured by the pressure infiltration method with liquid metal alloy.Design/methodology/approach: Ceramic preforms were manufactured by the method of sintering of ceramicpowder. The preform material consists of powder Condea Al2O3 CL 2500, however, as the forming factor ofthe structure of canals and pores inside the ceramic agglomerated framework the carbon fibers Sigrafil C10M250 UNS were used. Then ceramic preforms were infiltrated with liquid EN AC – AlSi12 aluminum alloy.Stereological and structure investigations of obtained composite materials were made on light microscope.Findings: It was proved that developed technology of manufacturing of composite materials with the pore ceramicAl2O3 infiltration ensures expected structure and can be used in practice.Practical implications: The developed technology allows to obtain method’s elements locally reinforced andcomposite materials with precise shape mapping.Originality/value: The received results show the possibility of obtaining the new composite materials being thecheaper alternative for other materials based on the ceramic fibers.

  12. Structures and properties of alumina-based ceramic for reconstructive oncology

    Science.gov (United States)

    Grigoriev, M. V.; Kulkov, S. N.

    2016-08-01

    The microstructure of alumina ceramics based on powders with a varying grain size has been investigated. Both commercial alumina powders and those fabricated by denitration of aluminum salts in high-frequency discharge plasma were used. It is shown that the variation of the sintering temperature and morphology of the initial powders of the particles leads to a change of the pore structure of ceramics from pore isolated clusters to a structure consisting of a ceramic skeleton and a large pore space. Changing the type of pore structure occurs at about 50% of porosity. The ceramic pore size distribution is bimodal. Dependencies final density vs initial density are linear; at the same time with increasing temperature, inclination of changes from positive to negative, indicating the change of sealing mechanisms. Extrapolation of these curves showed that they intersect with the values of density of about 2 g/cm3, which indicates the possibility of producing non-shrink ceramics. It is shown that the strength increases with increasing nanocrystalline alumina content in powder mixture. A change in the character the pore structure is accompanied by a sharp decrease in strength, which corresponds to the percolation transition in ceramics. These results showed that it is possible to obtain ceramic materials with the structure and properties similar to natural bone.

  13. An Experimental Study on Mechanical Modeling of Ceramics Based on Microstructure

    Directory of Open Access Journals (Sweden)

    Ya-Nan Zhang

    2015-11-01

    Full Text Available The actual grinding result of ceramics has not been well predicted by the present mechanical models. No allowance is made for direct effects of materials microstructure and almost all the mechanical models were obtained based on crystalline ceramics. In order to improve the mechanical models of ceramics, surface grinding experiments on crystalline ceramics and non-crystalline ceramics were conducted in this research. The normal and tangential grinding forces were measured to calculate single grit force and specific grinding energy. Grinding surfaces were observed. For crystalline alumina ceramics, the predictive modeling of normal force per grit fits well with the experimental result, when the maximum undeformed chip thickness is less than a critical depth, which turns out to be close to the grain size of alumina. Meanwhile, there is a negative correlation between the specific grinding energy and the maximum undeformed chip thickness. With the decreasing maximum undeformed chip thickness, the proportions of ductile removal and transgranular fracture increase. However, the grinding force models are not applicable for non-crystalline ceramic fused silica and the specific grinding energy fluctuates irregularly as a function of maximum undeformed chip thickness seen from the experiment.

  14. Production of 6cm x 6cm Micro-channel Plate Based Picosecond Photodetectors with the Argonne Small Tile Processing System (STPS)

    Science.gov (United States)

    Xia, Lei; Byrum, Karen; Demarteau, Marcel; Wagner, Robert; Walters, Dean; Wang, Jingbo; Xie, Junqi; Zhao, Huyue

    2015-04-01

    Microchannel plate (MCP) based photodetectors feature fast timing, good position resolution and compact form factor. However, traditional MCP photodetectors suffer from limited charge lifetime and high cost. The LAPPD collaboration, over the years, developed Atomic Layer Deposition (ALD) coated new generation MCP's and low cost glass packaging technology. Recently, the Argonne group commissioned its small form factor tile processing system and produced the first fully processed sealed photodetectors with glass packaging, using the ALD coated MCP's. We report the design, construction and commissioning of the system, and production of the first devices. Supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences and Office of High Energy Physics under Contract DE-AC02-06CH11357.

  15. Chirped-pulse amplification system based on chirp reversal and near-field spatial reversal with common tiled grating pair as stretcher and compressor.

    Science.gov (United States)

    Wang, Xiao; Wei, Xiaofeng; Hu, Yao; Zeng, Xiaoming; Zuo, Yanlei; Hao, Xin; Zhou, Kainan; Xie, Na; Zhang, Ying

    2012-08-10

    Chirped-pulse amplification system based on chirp reversal in optical parametric chirped-pulse amplification is proposed and experimentally demonstrated. The operation of this system can be described as negative stretching-temporal chirp reversal-energy amplification-negative compression, in which the pulse is stretched and compressed with the same gratings. Stand-alone stretcher adopting lenses or concave mirrors with large aperture can be omitted. Simulations showed that this work mode can also increase the cut-off band-pass of the whole system and increase the output energy by 15-17%. In addition, the stability of a tiled-grating compressor can be improved with this work mode. PMID:22885574

  16. Study on Microstructure of Alumina Based Rare Earth Ceramic Composite

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Analysis techniques such as SEM, TEM and EDAX were used to investigate the microstructure of rare earth reinforced Al2O3/(W, Ti)C ceramic composite. Chemical and physical compatibility of the composite was analyzed and interfacial microstructure was studied in detail. It is found that both Al2O3 and (W, Ti)C phases are interlaced with each other to form the skeleton structure in the composite. A small amount of pores and glass phases are observed inside the material which will inevitably influence the physical and mechanical property of the composite. Thermal residual stresses resulted from thermal expansion mismatch can then lead to the emergence of dislocations and microcracks. Interfaces and boundaries of different types are found to exist inside the Al2O3/(W, Ti)C rare earth ceramic composite, which is concerned with the addition of rare earth element and the extent of solid solution of ceramic phases.

  17. Fabrication of porous Al2O3-based ceramics using combustion synthesized powders

    Directory of Open Access Journals (Sweden)

    Jiahai Bai

    2012-03-01

    Full Text Available Porous Al2O3-based ceramics were fabricated from powders synthesized via a solution combustion process using starch and urea as fuels. Effects of the relative fuel-to-oxidant ratio (φe = 1.4, 1.6, 1.8 and 2.0, respectively on open porosity, pore size distribution and flexural strength of the as-prepared porous Al2O3-based ceramics were investigated. Experimental results revealed that the densification ability of the as-synthesized powders increased significantly as φe increased, and open porosity, pore size distribution and flexural strength of the porous ceramics exhibited remarkable dependence on the densification ability of the powders instead of the weight fraction of the charred organic residuals in the powders. SEM micrographs disclosed that the porous ceramics from the precursors with φe = 1.8 or 2.0 exhibited significantly homogenous microstructures including pore size and pore distribution.

  18. Gas Sensors Based on Ceramic p-n Heterocontacts

    Energy Technology Data Exchange (ETDEWEB)

    Seymen Murat Aygun

    2004-12-19

    Ceramic p-n heterocontacts based on CuO/ZnO were successfully synthesized and a systematic study of their hydrogen sensitivity was conducted. The sensitivity and response rates of CuO/ZnO sensors were studied utilizing current-voltage, current-time, and impedance spectroscopy measurements. The heterocontacts showed well-defined rectifying characteristics and were observed to detect hydrogen via both dc and ac measurements. Surface coverage data were derived from current-time measurements which were then fit to a two-site Langmuir adsorption model quite satisfactorily. The fit suggested that there should be two energetically different adsorption sites in the system. The heterocontacts were doped in an attempt to increase the sensitivity and the response rate of the sensor. First, the effects of doping the p-type (CuO) on the sensor characteristics were investigated. Doping the p-type CuO with both acceptor and isovalent dopants greatly improved the hydrogen sensitivity. The sensitivity of pure heterocontact observed via I-V measurements was increased from {approx}2.3 to {approx}9.4 with Ni doping. Dopants also enhanced the rectifying characteristics of the heterocontacts. Small amounts of Li addition were shown to decrease the reverse bias (saturation) current to 0.2 mA at a bias level of -5V. No unambiguous trends were observed between the sensitivity, the conductivity, and the density of the samples. Comparing the two phase microstructure to the single phase microstructure there was no dramatic increase in the sensitivity. Kinetic studies also confirmed the improved sensor characteristics with doping. The dopants decreased the response time of the sensor by decreasing the response time of one of the adsorption sites. The n-type ZnO was doped with both acceptor and donor dopants. Li doping resulted in the degradation of the p-n junction and the response time of the sensor. However, the current-voltage behavior of Ga-doped heterocontacts showed the best rectifying

  19. The Mu3e Tile Detector

    OpenAIRE

    Eckert, Hans Patrick

    2015-01-01

    The Mu3e experiment is designed to search for the lepton flavour violating decay μ→eee with a sensitivity of one in 10^16 decays. An observation of such a decay would be a clear sign of physics beyond the Standard Model. Achieving the targeted sensitivity requires a high precision detector with excellent momentum, vertex and time resolution. The Mu3e Tile Detector is a highly granular sub-detector system based on scintillator tiles with Silicon Photomultiplier (SiPM) readout, and aims at meas...

  20. Boron carbide-based ceramics via polymer route synthesis

    International Nuclear Information System (INIS)

    Boron carbide is a ceramic material with excellent high temperature physical properties. As compared to conventional techniques, the preparation of boron carbide from polymeric precursors is attractive as this technique offers a number of unique advantages. In this paper, the screening of polymeric precursors to boron carbide will be discussed. Two promising boron carbide, carborane containing polymeric precursors have resulted in 60-70 wt.% ceramic yields. The chemistry of polymer synthesis and the transformations from the polymer to amorphous and crystalline boron carbide were investigated with infrared spectroscopy, NMR spectroscopy, thermal analysis, and x-ray diffraction

  1. Improved performance of diatomite-based dental nanocomposite ceramics using layer-by-layer assembly

    Directory of Open Access Journals (Sweden)

    Lu X

    2012-04-01

    Full Text Available Xiaoli Lu1,2, Yang Xia1, Mei Liu1, Yunzhu Qian3, Xuefeng Zhou4, Ning Gu4, Feimin Zhang1,41Institute of Stomatology, Nanjing Medical University, Nanjing, 2Nantong Stomatological Hospital, Nantong, 3Center of Stomatology, The Second Affiliated Hospital of Suzhou University, Suzhou, 4Suzhou Institute, Southeast University, Suzhou, People's Republic of ChinaAbstract: To fabricate high-strength diatomite-based ceramics for dental applications, the layer-by-layer technique was used to coat diatomite particles with cationic [poly(allylamine hydrochloride] and anionic [poly(sodium 4-styrenesulfonate] polymers to improve the dispersion and adsorption of positively charged nano-ZrO2 (zirconia as a reinforcing agent. The modified diatomite particles had reduced particle size, narrower size distribution, and were well dispersed, with good adsorption of nano-ZrO2. To determine the optimum addition levels for nano-ZrO2, ceramics containing 0, 20, 25, 30, and 35 wt% nano-ZrO2 were sintered and characterized by the three-point bending test and microhardness test. In addition to scanning electron microscopy, propagation phase-contrast synchrotron X-ray microtomography was used to examine the internal structure of the ceramics. The addition of 30 wt% nano-ZrO2 resulted in the highest flexural strength and fracture toughness with reduced porosity. Shear bond strength between the core and veneer of our diatomite ceramics and the most widely used dental ceramics were compared; the shear bond strength value for the diatomite-based ceramics was found to be significantly higher than for other groups (P < 0.05. Our results show that diatomite-based nanocomposite ceramics are good potential candidates for ceramic-based dental materials.Keywords: layer-by-layer, diatomite, nanoceramics, zirconia (ZrO2, dental materials

  2. Plasma sprayed ceramic thermal barrier coating for NiAl-based intermetallic alloys

    Science.gov (United States)

    Miller, Robert A. (Inventor); Doychak, Joseph (Inventor)

    1994-01-01

    A thermal barrier coating system consists of two layers of a zirconia-yttria ceramic. The first layer is applied by low pressure plasma spraying. The second layer is applied by conventional atmospheric pressure plasma spraying. This facilitates the attachment of a durable thermally insulating ceramic coating directly to the surface of a highly oxidation resistant NiAl-based intermetallic alloy after the alloy has been preoxidized to promote the formation of a desirable Al2O3 scale.

  3. Producing superhydrophobic roof tiles

    Science.gov (United States)

    Carrascosa, Luis A. M.; Facio, Dario S.; Mosquera, Maria J.

    2016-03-01

    Superhydrophobic materials can find promising applications in the field of building. However, their application has been very limited because the synthesis routes involve tedious processes, preventing large-scale application. A second drawback is related to their short-term life under outdoor conditions. A simple and low-cost synthesis route for producing superhydrophobic surfaces on building materials is developed and their effectiveness and their durability on clay roof tiles are evaluated. Specifically, an organic-inorganic hybrid gel containing silica nanoparticles is produced. The nanoparticles create a densely packed coating on the roof tile surface in which air is trapped. This roughness produces a Cassie-Baxter regime, promoting superhydrophobicity. A surfactant, n-octylamine, was also added to the starting sol to catalyze the sol-gel process and to coarsen the pore structure of the gel network, preventing cracking. The application of ultrasound obviates the need to use volatile organic compounds in the synthesis, thereby making a ‘green’ product. It was also demonstrated that a co-condensation process effective between the organic and inorganic species is crucial to obtain durable and effective coatings. After an aging test, high hydrophobicity was maintained and water absorption was completely prevented for the roof tile samples under study. However, a transition from a Cassie-Baxter to a Wenzel state regime was observed as a consequence of the increase in the distance between the roughness pitches produced by the aging of the coating.

  4. An automated data management/analysis system for space shuttle orbiter tiles. [stress analysis

    Science.gov (United States)

    Giles, G. L.; Ballas, M.

    1982-01-01

    An engineering data management system was combined with a nonlinear stress analysis program to provide a capability for analyzing a large number of tiles on the space shuttle orbiter. Tile geometry data and all data necessary of define the tile loads environment accessed automatically as needed for the analysis of a particular tile or a set of tiles. User documentation provided includes: (1) description of computer programs and data files contained in the system; (2) definitions of all engineering data stored in the data base; (3) characteristics of the tile anaytical model; (4) instructions for preparation of user input; and (5) a sample problem to illustrate use of the system. Description of data, computer programs, and analytical models of the tile are sufficiently detailed to guide extension of the system to include additional zones of tiles and/or additional types of analyses

  5. The Development of a General Purpose ARM-based Processing Unit for the TileCal sROD

    CERN Multimedia

    Cox, Mitchell A

    2014-01-01

    The Large Hadron Collider at CERN generates enormous amounts of raw data which present a serious computing challenge. After planned upgrades in 2022, the data output from the ATLAS Tile Calorimeter will increase by 200 times to 41 Tb/s! ARM processors are common in mobile devices due to their low cost, low energy consumption and high performance. It is proposed that a cost-effective, high data throughput Processing Unit (PU) can be developed by using several consumer ARM processors in a cluster configuration to allow aggregated processing performance and data throughput while maintaining minimal software design difficulty for the end-user. This PU could be used for a variety of high-level functions on the high-throughput raw data such as spectral analysis and histograms to detect possible issues in the detector at a low level. High-throughput I/O interfaces are not typical in consumer ARM System on Chips but high data throughput capabilities are feasible via the novel use of PCI-Express as the I/O interface t...

  6. The Development of a General Purpose ARM-based Processing Unit for the ATLAS TileCal sROD

    CERN Document Server

    Cox, Mitchell Arij; The ATLAS collaboration; Mellado Garcia, Bruce Rafael

    2015-01-01

    The Large Hadron Collider at CERN generates enormous amounts of raw data which present a serious computing challenge. After Phase-II upgrades in 2022, the data output from the ATLAS Tile Calorimeter will increase by 200 times to 41 Tb/s! ARM processors are common in mobile devices due to their low cost, low energy consumption and high performance. It is proposed that a cost-effective, high data throughput Processing Unit (PU) can be developed by using several consumer ARM processors in a cluster configuration to allow aggregated processing performance and data throughput while maintaining minimal software design difficulty for the end-user. This PU could be used for a variety of high-level functions on the high-throughput raw data such as spectral analysis and histograms to detect possible issues in the detector at a low level. High-throughput I/O interfaces are not typical in consumer ARM System on Chips but high data throughput capabilities are feasible via the novel use of PCI-Express as the I/O interface ...

  7. The development of a general purpose ARM-based processing unit for the ATLAS TileCal sROD

    International Nuclear Information System (INIS)

    After Phase-II upgrades in 2022, the data output from the LHC ATLAS Tile Calorimeter will increase significantly. ARM processors are common in mobile devices due to their low cost, low energy consumption and high performance. It is proposed that a cost-effective, high data throughput Processing Unit (PU) can be developed by using several consumer ARM processors in a cluster configuration to allow aggregated processing performance and data throughput while maintaining minimal software design difficulty for the end-user. This PU could be used for a variety of high-level functions on the high-throughput raw data such as spectral analysis and histograms to detect possible issues in the detector at a low level. High-throughput I/O interfaces are not typical in consumer ARM System on Chips but high data throughput capabilities are feasible via the novel use of PCI-Express as the I/O interface to the ARM processors. An overview of the PU is given and the results for performance and throughput testing of four different ARM Cortex System on Chips are presented

  8. Zirconium oxide based ceramic solid electrolytes for oxygen detection

    International Nuclear Information System (INIS)

    Taking advantage of the high thermal shock resistance of zirconia-magnesia ceramics and the high oxide ion conductivity of zirconia-yttria ceramics, composites of these ceramics were prepared by mixing, pressing and sintering different relative concentrations of ZrO2: 8.6 mol% MgO and ZrO2: 3 mol% Y2O3 solid electrolytes. Microstructural analysis of the composites was carried out by X-ray diffraction and scanning electron microscopy analyses. The thermal behavior was studied by dilatometric analysis. The electrical behavior was evaluated by the impedance spectroscopy technique. An experimental setup was designed for measurement the electrical signal generated as a function of the amount of oxygen at high temperatures. The main results show that these composites are partially stabilized (monoclinic, cubic and tetragonal) and the thermal behavior is similar to that of ZrO2: 8.6 mol% MgO materials used in disposable high temperature oxygen sensors. Moreover, the results of analysis of impedance spectroscopy show that the electrical conductivity of zirconia:magnesia is improved with zirconia-yttria addition and that the electrical signal depends on the amount of oxygen at 1000 deg C, showing that the ceramic composites can be used in oxygen sensors. (author)

  9. Dispersion of impurities in pyrochlore/zirconolite-based ceramics

    International Nuclear Information System (INIS)

    Pyrochlore-rich and zirconolite-rich ceramics have been developed for the immobilization of excess weapons Pu. The ceramics are composed of a mixture of pyrochlore, zirconolite, brannerite and rutile. Impurity ions are present in most Pu-waste streams. Most of these impurities can be incorporated into the phases present in the ceramic; however some, such as B and Si, can promote the formation of additional phases. In this work, the impurity ions were classed into sets with supposedly the same valency (2+, 3+, 4+, 5+ and 6+). One set containing Np and Th and another set containing the glass formers (Al, Si, B, Na and K) were also made. These sets of elements were then added to a 'baseline' ceramics of nominal sintered composition, 95 wt.% pyrochlore (Ca0.89Gd0.22(Pu or Ce)0.22U0.44Hf0.23Ti2O7) and 5 wt.% HF-doped rutile, (Ti0.9Hf0.1O2). A sufficient amount of each of these sets of impurity ions was added so that the primary phases of the baseline ceramic were saturated with them and secondary phases formed. Both Pu/U-doped Ce/U-doped samples were made. The impurity elements were added as nitrates to an alkoxide-route precursor, which was calcined and then ball milled. Pellets were pressed from the powder and sintered in Ar, air or 3.7% H2 in Ar at about 1350 degrees Celsius for 4 hours. The obtained results are summarized in this work. As a matter of fact, most of the ions can be accommodated in the ceramic, but the partitioning across the different phases in the ceramic is not even. The groups will preferentially move to certain phases or, if sufficient amounts are present, result in the formation of new phases. The conclusion is that all ions of similar size and valency behave in a similar manner unless there are volatility problems

  10. Effect of silica sol on the properties of alumina-based ceramic core composites

    International Nuclear Information System (INIS)

    A series of alumina-based ceramic cores sintered at 1300 deg. C, 1400 deg. C, and 1500 deg. C for 5 h were prepared, and the phases and microstructures were characterized by X-ray diffraction and scanning electron microscopy. The effect of colloidal silica sols on the properties of ceramic core was discussed. The properties of these materials were determined. The microstructure of the core formed on the substantially un-reacted coarse Al2O3 particles was predominantly a polycrystalline composition consisting essentially of in situ synthesized 3Al2O3.2SiO2. The colloidal silica sol contents do not have an appreciable effect on the densification and shrinkage of alumina ceramic core. The ceramic cores of 5 wt% colloidal silica sol contents sintered at 1500 deg. C for 5 h showed the smallest creep deformation in the present research.

  11. Effect of soda-lime glass on sintering and technological properties of porcelain stoneware tiles

    OpenAIRE

    Matteucci, F; Dondi, M.; G. Guarini

    2002-01-01

    The feasibility of waste glass recycling in ceramic tile production was assessed with special reference to fully vitrified products (porcelain stoneware). Soda-lime float or container glass was introduced, in replacement of sodic feldspar, in typical porcelain stoneware bodies (up to 10% wt) that underwent a laboratory simulation of tilemaking process, with a technological and compositional characterization of both fired and unfired tiles. Soda-lime glass had no significant effect on semi-fin...

  12. Ammann Tilings: A Decsription and Classification

    CERN Document Server

    Durand, Bruno; Vereshchagin, Nikolay

    2011-01-01

    We suggest a description of all tilings of a plane by Ammann tiles. Using that description we show that there are continuum many such tilings. As it is known, all such tilings are aperiodic. We derive from this fact a new construction of an aperiodic Wang tile set.

  13. Characterization of composite materials based on cement-ceramic powder blended binder

    Science.gov (United States)

    Kulovaná, Tereza; Pavlík, Zbyšek

    2016-06-01

    Characterization of newly developed composite mortars with incorporated ceramic powder coming from precise brick cutting as partial Portland cement replacement up to 40 mass% is presented in the paper. Fine ceramic powder belongs to the pozzolanic materials. Utilization of pozzolanic materials is accompanied by lower request on energy needed for Portland clinker production which generally results in lower production costs of blended binder and lower CO2 emission. In this paper, the ceramic powder is used in cement based mortar composition in amount of 8, 16, 24, 32, and 40 mass% of cement. Chemical composition of ceramic powder is analyzed by X-Ray Fluorescence and X-Ray Diffraction. The particle size distribution of ceramics is accessed on laser diffraction principle. For 28 days cured mortar samples, basic physical and mechanical properties are experimentally determined. The obtained results demonstrate that ceramic powder has potential to replace a part of Portland cement in composition of cement based composites and to reduce negative environmental impact of their production.

  14. Mechanical behavior of alumina and alumina-feldspar based ceramics in an acetic acid (4%) environment

    International Nuclear Information System (INIS)

    This study investigates the mechanical properties of alumina-feldspar based ceramics when exposed to an aggressive environment (acetic acid 4%). Alumina ceramics containing different concentrations of feldspar (0%, 1%, 5%, 10%, or 40%) were sintered at either 1300, 1600, or 1700 oC. Flaws (of width 0%, 30%, or 50%) were introduced into the specimens using a saw. Half of these ceramic bodies were exposed to acetic acid. Their flexural strength, KIC, and porosity were measured and the fractured samples were evaluated using scanning electronic- and optical microscopy. It was found that in the ceramic bodies sintered at 1600 oC, feldspar content up to 10% improved flexural strength and KIC, and reduced porosities. Generally, it was found that acetic acid had a weakening effect on the flexural strength of samples sintered at 1700 oC but a beneficial effect on KIC of ceramics sintered at 1600 oC. It was concluded that alumina-based ceramics with feldspar content up to 10% and sintered at higher temperatures would perform better in an aggressive environment similar to oral cavity.

  15. Geometric realizations of substitutive tilings

    CERN Document Server

    Bedaride, Nicolas

    2011-01-01

    We define 2-dimensional topological substitutions. A tiling of the Euclidean plane, or of the hyperbolic plane, is substitutive if the underlying 2-complex can be obtained by iteration of a 2-dimensional topological substitution. We prove that there is no primitive substitutive tiling of the hyperbolic plane $\\mathbb{H}^2$. However, we give an example of substitutive tiling of $\\Hyp^2$ which is non-primitive.

  16. Utilização do resíduo da extração de esmeraldas em uma formulação de massa de revestimento cerâmico Use of the extraction residue of emeralds in a formulation mass of ceramic tiles

    Directory of Open Access Journals (Sweden)

    R. F. Cavalcante

    2012-06-01

    volumes of waste generated and emerald are constantly abandoned in the environment, contributing negatively to their preservation. On the other hand the interest in the use of mining waste as an additive in production of ceramic materials has grown among researchers in recent years. The ceramic industry is constantly seeking to expand the market for the sector and trying to improve product quality and increase the variety of applications. The technology of obtaining ceramic coating that uses waste from mining is still a largely unexplored market. Thus, the purpose of this study was to characterize the waste generated from mining emerald as well as to evaluate its potential use as raw material for production melting of ceramic tiles. Ceramic mixtures were prepared from raw materials characterized by X-ray fluorescence and X-ray diffraction. Five compositions were prepared using the waste codes of emeralds from 0%, 10%, 20%, 30% and 40%. Samples were prepared by pressing, sintered at 1000, 1100 and 1200 ºC and characterized to establish their mineralogical composition, water absorption, linear shrinkage and modulus of rupture. The results showed that the residue of emeralds studied can be embedded in the mass of ceramic tiles up to 20% in replacement of feldspar without compromising the end product properties.

  17. Eco-innovation an evolution of innovation? Empirical analysis at the Spanish tile ceramic industry; Eco-innovacion, una evolucion de la innovacion? Analisis empirico en la industria ceramica espanola

    Energy Technology Data Exchange (ETDEWEB)

    Segarra-Ona, M.; Peiro-Signes, A.; Miret-Pastor, L.; Albors-Garrigos, J.

    2011-07-01

    Innovation and sustainable development are considered to be economic drivers and crucial in fixing competitive position of companies. Eco-innovation, known as a synergic relation among both concepts must be an element to consider when designing the company's strategy. The objective of this paper is to analyze which are the variables that determine that innovative companies go beyond and consider the improvement of their environmental impact as an output when developing innovating activities. This research considers firms belonging to the Spanish tile industry. Data has been provided by PITEC Database. The paper identifies the moderating factors that influence the eco-innovative behavior of firms. (Author)

  18. Sediment management and the renewability of floodplain clay for structural ceramics

    OpenAIRE

    Meulen, van der, A.; Wiersma, A.P.; Perk, van der, M.; Middelkoop, H.; Hobo, N.

    2009-01-01

    The Netherlands has vast resources of clay that are exploited for the fabrication of structural ceramic products such as bricks and roof tiles. Most clay is extracted from the so-called embanked floodplains along the rivers Rhine and Meuse, areas that are flooded during high-discharge conditions. Riverside clay extraction is-at least in theory-compensated by deposition. Based on a sediment balance (deposition versus extraction), we explore the extent to which clay can be regarded as a renewab...

  19. Full Ceramic Fuel Cells Based on Strontium Titanate Anodes, An Approach Towards More Robust SOFCs

    DEFF Research Database (Denmark)

    Holtappels, Peter; Irvine, J.T.S.; Iwanschitz, B.; Kuhn, Luise Theil; Lu, L.Y.; Ma, Q.; Malzbender, J.; Mai, A.; Ramos, Tania; Rass-Hansen, J.; Reddy Sudireddy, Bhaskar; Tietz, F.; Vasechko, V.; Veltzé, Sune; Verbraeken, M.C.

    2013-01-01

    The persistent problems with Ni-YSZ cermet based SOFCs, with respect to redox stability and tolerance towards sulfur has stimulated the development of a full ceramic cell based on strontium titanate(ST)- based anodes and anode support materials, within the EU FCH JU project SCOTAS-SOFC. Three dif...

  20. Si3N4-Based Ceramic With Greater Hot Strength

    Science.gov (United States)

    Dutta, S.; Buzek, B.

    1986-01-01

    Zyttrite-doped material outperforms MgO-doped material above 1,200 degrees C. New ceramic material produced by addition of 10 weight percent zyttrite (yttria-stabilized zirconia) to (silicon nitride) offers significantly-improved high-temperature properties (those of MgO-doped Si3N4 ceramic). Work also showed that controlled Si3N4 powder with 10 weight percent zyttrite, significant improvement in room-temperature strength achieved. Variety of high-temperature structural applications are silicon nitride and silicon carbide. Potential for use in aircraft and automobile engines and in electric-power generating systems. Improved properties strongly suggest that the 10-weight percent zyttrite/Si3N4 material has strong potential for high-temperature applications.

  1. Water-induced dc and ac degradations in TiO2-based ceramic capacitors

    International Nuclear Information System (INIS)

    Water-induced degradations of TiO2-based ceramic capacitors in the presence of dc and ac voltages are reported in this paper. Atomic hydrogen generated by electrolysis of water using dc voltages reduced TiO2-based ceramics at ambient temperature. The resulting degradation was characterized by an increase in capacitance, a large dielectric loss and a dramatic decrease in insulation resistance. Hydrogen and oxygen generated by the electrolysis of water using ac voltages reacted with TiO2-based ceramics. The resulting degradation was characterized by a decrease in capacitance, a large dielectric loss, but no noticeable changes in insulation resistance. Water played a vital role in both dc and ac degradations of TiO2-based capacitors and an effort should be made to prevent water-induced degradations

  2. Improvement of the steel quality through zirconia base ceramic filter

    International Nuclear Information System (INIS)

    At the end of production, the steel presents inclusions own to the making process. Ceramics filters, with controlled porosity, are being produced to eliminate the impurities, so as to increase the good quality steel production. This work studies the optimization of the zirconia filters composition and production for siderurgical processes application. The study was done through the granulometric control, using BET, XRD and Hg Porosimetry. (author)

  3. Properties of ceramics based on cerium dioxide with crystalline filaments

    International Nuclear Information System (INIS)

    Problems of the increase of thermal resistance of ceramics on the basis of cerium dioxide with the interduction of filamentous crystals (FC) of CeO2 and MgO have been considered. It is established that FC of MgO and CeO2 are dissolved in the matrix, foAming fine oblong pores, promoting relaxation of thermal strains and preventing crack propagation, which increases the material thermal resistance

  4. Parallelogram tilings, Worms and Finite Orientations

    CERN Document Server

    Frettlöh, Dirk

    2012-01-01

    This paper studies properties of tilings of the plane by parallelograms. In particular it is established that in parallelogram tilings using a finite number of shapes all tiles occur in only finitely many orientations.

  5. Tile-in-ONE

    CERN Document Server

    Cunha, R; The ATLAS collaboration; Sivolella, A; Ferreira, F; Maidantchik, C

    2013-01-01

    The Tile calorimeter is one of the sub-detectors of ATLAS. In order to ensure its proper operation and assess the quality of data, many tasks are to be performed by means of many tools which were developed independently to satisfy different needs. Thus, these systems are commonly implemented without a global perspective of the detector and lack basic software features. Besides, in some cases they overlap in the objectives and resources with another one. It is therefore evident the necessity of an infrastructure to allow the implementation of any functionality without having to duplicate the effort while being possible to integrate with an overall view of the detector status.\

  6. Tiled QR factorization algorithms

    OpenAIRE

    Bouwmeester, Henricus; Jacquelin, Mathias; Langou, Julien; Robert, Yves

    2011-01-01

    This work revisits existing algorithms for the QR factorization of rectangular matrices composed of p-by-q tiles, where p >= q. Within this framework, we study the critical paths and performance of algorithms such as Sameh and Kuck, Modi and Clarke, Greedy, and those found within PLASMA. Although neither Modi and Clarke nor Greedy is optimal, both are shown to be asymptotically optimal for all matrices of size p = q^2 f(q), where f is any function such that \\lim_{+\\infty} f= 0. This novel and...

  7. Tiles for Reo

    Science.gov (United States)

    Arbab, Farhad; Bruni, Roberto; Clarke, Dave; Lanese, Ivan; Montanari, Ugo

    Reo is an exogenous coordination model for software components. The informal semantics of Reo has been matched by several proposals of formalization, exploiting co-algebraic techniques, constraint-automata, and coloring tables. We aim to show that the Tile Model offers a flexible and adequate semantic setting for Reo, such that: (i) it is able to capture context-aware behavior; (ii) it is equipped with a natural notion of behavioral equivalence which is compositional; (iii) it offers a uniform setting for representing not only the ordinary execution of Reo systems but also dynamic reconfiguration strategies.

  8. Crystallisation Kinetics of a β-Spodumene-Based Glass Ceramic

    Directory of Open Access Journals (Sweden)

    Oscar Rubem Klegues Montedo

    2012-01-01

    Full Text Available LZSA (Li2O-ZrO2-SiO2-Al2O3 glass ceramic system has shown high potential to obtain LTCC laminate tapes at low sintering temperature (<1000°C for several applications, such as screen-printed electronic components. Furthermore, LZSA glass ceramics offer interesting mechanical, chemical, and thermal properties, which make LZSA also a potential candidate for fabricating multilayered structures processed by Laminated Objects Manufacturing (LOM technology. The crystallization kinetics of an LZSA glass ceramic with a composition of 16.9Li2O⋅5.0ZrO2⋅65.1SiO2⋅8.6Al2O3 was investigated using nonisothermal methods by differential thermal analysis and scanning electronic microscopy. Apparent activation energy for crystallization was found to be in the 274–292 kJ⋅mol−1 range, and an Avrami parameter n of 1 was obtained that is compared very favorably with SEM observations.

  9. A study on (K, Na) NbO3 based multilayer piezoelectric ceramics micro speaker

    International Nuclear Information System (INIS)

    A flat panel micro speaker was fabricated from (K, Na) NbO3 (KNN)-based multilayer piezoelectric ceramics by a tape casting and cofiring process using Ag-Pd alloys as an inner electrode. The interface between ceramic and electrode was investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). The acoustic response was characterized by a standard audio test system. We found that the micro speaker with dimensions of 23 × 27 × 0.6 mm3, using three layers of 30 μm thickness KNN-based ceramic, has a high average sound pressure level (SPL) of 87 dB, between 100 Hz–20 kHz under five voltage. This result was even better than that of lead zirconate titanate (PZT)-based ceramics under the same conditions. The experimental results show that the KNN-based multilayer ceramics could be used as lead free piezoelectric micro speakers. (paper)

  10. 一辊多色多图立体胶辊印刷技术及产品开发%Development of One-Rubber Roller Printer for 3D Multicolor Multi- Image Solution in New Ceramic Tile Production

    Institute of Scientific and Technical Information of China (English)

    余国明; 赖丽红; 梁泽荣; 王勇

    2012-01-01

    在高清三维胶辊印刷技术的基础上,通过对胶辊印刷装备进行重大改进和花釉配方组成优化,研究开发一辊多色多图立体胶辊印刷技术及凹凸拼图釉面砖产品。试验表明,采用本工作开发的一辊多色多图立体胶辊印刷技术可成功实现凹凸拼图釉面砖产品生产,大大减少印花装饰过程胶辊数量和明显提高了产品质量稳定性。%By improving the printer and optimizing the recipes of decorative glazes, 3D Multicolor multi-image printing with a single rubber roller was developed from the existing 3D high definition rubber roller printing, by which concave and convex glazed tiles for a collage image were produced. Experimental results show that the one roller printing technique can be used to produce concave and convex glazed tiles of more guaranteed quality for collage images with fewer rubber rollers.

  11. When Shape Matters: Deformations of Tiling Spaces

    OpenAIRE

    Clark, Alex; Sadun, Lorenzo

    2003-01-01

    We investigate the dynamics of tiling dynamical systems and their deformations. If two tiling systems have identical combinatorics, then the tiling spaces are homeomorphic, but their dynamical properties may differ. There is a natural map ${\\mathcal I}$ from the parameter space of possible shapes of tiles to $H^1$ of a model tiling space, with values in $\\R^d$. Two tiling spaces that have the same image under ${\\mathcal I}$ are mutually locally derivable (MLD). When the difference of the imag...

  12. Ternary and senary representations using DNA double-crossover tiles

    CERN Document Server

    Kim, Byeonghoon; Son, Junyoung; Kim, Junghoon; Hwang, Si Un; Dugasani, Sreekantha Reddy; Kim, Min Hyeok; Kim, Byung-Dong; Chang, Iksoo; Liu, Wing Kam; Kim, Moon Ki; Park, Sung Ha

    2016-01-01

    The information capacity of double-crossover (DX) tiles was successfully increased beyond a binary representation to higher base representations. By controlling the length and the position of DNA hairpins on the DX tile, ternary and senary (base-3 and base-6) digit representations were realized and verified by atomic force microscopy (AFM). Also, normal mode analysis (NMA) was carried out to study the mechanical characteristics of each structure.

  13. Potassium Sodium Niobate-Based Lead-Free Piezoelectric Multilayer Ceramics Co-Fired with Nickel Electrodes

    Directory of Open Access Journals (Sweden)

    Shinichiro Kawada

    2015-11-01

    Full Text Available Although lead-free piezoelectric ceramics have been extensively studied, many problems must still be overcome before they are suitable for practical use. One of the main problems is fabricating a multilayer structure, and one solution attracting growing interest is the use of lead-free multilayer piezoelectric ceramics. The paper reviews work that has been done by the authors on lead-free alkali niobate-based multilayer piezoelectric ceramics co-fired with nickel inner electrodes. Nickel inner electrodes have many advantages, such as high electromigration resistance, high interfacial strength with ceramics, and greater cost effectiveness than silver palladium inner electrodes. However, widely used lead zirconate titanate-based ceramics cannot be co-fired with nickel inner electrodes, and silver palladium inner electrodes are usually used for lead zirconate titanate-based piezoelectric ceramics. A possible alternative is lead-free ceramics co-fired with nickel inner electrodes. We have thus been developing lead-free alkali niobate-based multilayer ceramics co-fired with nickel inner electrodes. The normalized electric-field-induced thickness strain (Smax/Emax of a representative alkali niobate-based multilayer ceramic structure with nickel inner electrodes was 360 pm/V, where Smax denotes the maximum strain and Emax denotes the maximum electric field. This value is about half that for the lead zirconate titanate-based ceramics that are widely used. However, a comparable value can be obtained by stacking more ceramic layers with smaller thicknesses. In the paper, the compositional design and process used to co-fire lead-free ceramics with nickel inner electrodes are introduced, and their piezoelectric properties and reliabilities are shown. Recent advances are introduced, and future development is discussed.

  14. Efeito da adição de resíduo de rocha ornamental nas propriedades tecnológicas e microestrutura de piso cerâmico vitrificado Effect of the addition of ornamental rock waste on the technological properties and microstructure of vitrified ceramic floor tiles

    Directory of Open Access Journals (Sweden)

    A. J. Souza

    2011-06-01

    Full Text Available A indústria de rochas ornamentais gera grandes quantidades de resíduos sólidos na forma de pós finos. Estes resíduos, quando descartados no ambiente, provocam impacto ambiental negativo. Foi feito um estudo sobre a influência de um resíduo de rocha ornamental nas propriedades e microestrutura de piso cerâmico vitrificado. Foi preparada uma série de massas cerâmicas contendo até 30% em peso de resíduo de rocha ornamental. Peças cerâmicas foram preparadas por prensagem uniaxial e sinterizadas entre 1190 e 1250 ºC em um ciclo de queima rápida. As seguintes propriedades tecnológicas foram determinadas: retração linear, absorção de água, massa específica aparente, e tensão de ruptura a flexão. A evolução da microestrutura e a análise de fases foram acompanhadas por microscopia eletrônica de varredura e difração de raios X. Os resultados mostraram que adições de até 30% em peso de resíduo de rocha ornamental causaram variações significativas na generalidade das propriedades tecnológicas da massa cerâmica de referência. A microestrutura das peças cerâmicas também foi influenciada com a incorporação do resíduo estudado. Os resultados também mostram que a substituição de feldspato sódico por resíduo de rocha ornamental nas massas cerâmicas tende a melhorar a qualidade do piso cerâmico.The ornamental rock industries generate huge amounts of solid wastes (fine powders. These wastes as disposed in the environment generate negative environmental impacts. In this work a study was done on the influence of an ornamental rock waste in the technological properties and microstructure of vitrified floor tile. A series of ceramic pastes were prepared with additions of up to 30 wt% of waste. Ceramic pieces were prepared by uniaxial pressing and sintered between 1190 and 1250 ºC using a fast-firing cycle. The following technological properties were determined: linear shrinkage, water absorption, apparent density

  15. Fabrication of ceramic preforms based on Al2O3 CL 2500 powder

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2006-08-01

    Full Text Available Purpose: The aim of a work is to elaborate the method of manufacturing the porous, ceramic preforms based onAl2O3 particles used as the reinforcement in order to produce modern metal matrix composite materials.Design/methodology/approach: Semi-finished products were manufactured by the method of sintering ofceramic powder. The preform material consists of powder Condea Al2O3 Cl 2500, however, as the forming factorof the structure of canals and pores inside the ceramic, agglomerated framework the carbon fibres Sigrafil C10M250 UNS were used. The investigations of the structure of powder Al2O3 Condea Cl 2500, the used carbonfibres and the obtained ceramic preforms on the scanning electron microscope (SEM have been made. Themeasurement of permeability of the obtained materials on the specially designed station has also been made.Findings: The obtained preforms are characterised by volumetric participation of ceramic phase of 15 – 31%,what is the result of differential addition of the pores forming factor, and the high permeability indicates on “theopen porosity”.Research limitations/implications: The basic limit of the mentioned method is the possibility of obtainingpreforms of porosity less than 85%, where in case of using the ceramic fibres the pores can be more than 90%of material volumetric.Practical implications: The manufactured ceramic preforms are widely used as the reinforcement to producethe composite materials by the method of infiltration. That method allows manufacturing the metal elementslocally reinforced and the near-net shape composite products.Originality/value: The received results show the possibility of obtaining the new preforms being the cheaperalternative for semi-finished products based on the ceramic fibres and the use of carbon fibres as the poresforming agent indicate that it is the high-quality process.

  16. On the comparison of the ballistic performance of 10% zirconia toughened alumina and 95% alumina ceramic target

    International Nuclear Information System (INIS)

    Ballistic performance of different type of ceramic materials subjected to high velocity impact was investigated in many theoretical, experimental and numerical studies. In this study, a comparison of ballistic performance of 95% alumina ceramic and 10% zirconia toughened alumina (ZTA) ceramic tiles was analyzed theoretically and experimentally. Spherical cavity model based on the concepts of mechanics of compressible porous media of Galanov was used to analyze the relation of target resistance and static mechanical properties. Experimental studies were carried out on the ballistic performance of above two types of ceramic tiles based on the depth of penetration (DOP) method, when subjected to normal impact of tungsten long rod projectiles. Typical damaged targets were presented. The residual depth of penetration on after-effect target was measured in all experiments, and the ballistic efficiency factor of above two types ceramic plates were determined. Both theoretical and experimental results show that the improvement on ballistic resistance was clearly observed by increasing fracture toughness in ZTA ceramics.

  17. Cement-based piezoelectric ceramic composites for sensor applications in civil engineering

    Science.gov (United States)

    Dong, Biqin

    The objectives of this thesis are to develop and apply a new smart composite for the sensing and actuation application of civil engineering. Piezoelectric ceramic powder is incorporated into cement-based composite to achieve the sensing and actuation capability. The research investigates microstructure, polarization and aging, material properties and performance of cement-based piezoelectric ceramic composites both theoretically and experimentally. A hydrogen bonding is found at the interface of piezoelectric ceramic powder and cement phase by IR (Infrared Ray), XPS (X-ray Photoelectron Spectroscopy) and SIMS (Secondary Ion Mass Spectroscopy). It largely affects the material properties of composites. A simple first order model is introduced to explain the poling mechanism of composites and the dependency of polarization is discussed using electromechanical coupling coefficient kt. The mechanisms acting on the aging effect is explored in detail. Dielectrical, piezoelectric and mechanical properties of the cement-based piezoelectric ceramic composites are studied by experiment and theoretical calculation based on modified cube model (n=1) with chemical bonding . A complex circuit model is proposed to explain the unique feature of impedance spectra and the instinct of high-loss of cement-based piezoelectric ceramic composite. The sensing ability of cement-based piezoelectric ceramic composite has been evaluated by using step wave, sine wave, and random wave. It shows that the output of the composite can reflects the nature and characteristics of mechanical input. The work in this thesis opens a new direction for the current actuation/sensing technology in civil engineering. The materials and techniques, developed in this work, have a great potential in application of health monitoring of buildings and infrastructures.

  18. Stochastic Flips on Dimer Tilings

    CERN Document Server

    Fernique, Thomas

    2011-01-01

    This paper introduces a Markov process inspired by the problem of quasicrystal growth. It acts over dimer tilings of the triangular grid by randomly performing local transformations, called {\\em flips}, which do not increase the number of identical adjacent tiles (this number can be thought as the tiling energy). Fixed-points of such a process play the role of quasicrystals. We are here interested in the worst-case expected number of flips to converge towards a fixed-point. Numerical experiments suggest a bound quadratic in the number n of tiles of the tiling. We prove a O(n^2.5) upper bound and discuss the gap between this bound and the previous one. We also briefly discuss the average-case.

  19. Study of some ceramic systems based on silicium oxide

    International Nuclear Information System (INIS)

    Increased interest in glass-ceramics arises from their potential applications. Comparatively with ordinary ceramics, gel-derived ceramics offer the advantage of good chemical homogeneity and purity and a better control of physical and chemical properties. Also, gel-derived glass-ceramics can be obtained at lower temperatures. In this paper the 0.15Gd2O30.85(0.95SiO20.05Na2O) gel-derived glass-ceramic and 0.95SiO-20.05Na2O gel-derived ceramic heat treated at 250 deg. C, 500 deg. C and 1000 deg. C were studied by X -ray diffraction, IR spectroscopic and magnetic susceptibility measurements. Samples of 0.15Gd2O30.85(0.95SiO20.05Na2O) composition and of 0.95SiO20.05Na2O composition were prepared starting from tetraethoxysilane (99.9% purity) as source of silica, natrium peroxide and gadolinium oxide. Gd2O3 (99.99% purity) and Na2O2 (99,95% purity) were purchased from Aldrich and Merck, respectively. The X-ray diffraction measurements were carried out on a DRON 3 diffractometer using CuKα radiation. The diffraction patterns were compared to standard patterns for phase's identification. Infrared absorption spectra were measured at room temperature (∼20 deg. C) in the range 4000-400 cm-1 with a resolution of 4 cm-1 by an infrared spectrophotometer type FT-IR Vector 25 Brucker using the KBr pellet technique. Magnetic susceptibility measurements were performed using a Weiss type magnetic balance in the temperature range 80-300 K. The accuracy of the temperature control was less than ±0.1 K over the whole range and the overall accuracy of the measurements of magnetic moment was less than ±0.5%. The X-ray diffraction patterns of the all samples, points out that the heat-treatment has a great importance for the evolution of the crystallisation process. The presence of the gadolinium oxide in the 0.95SiO20.05Na2O matrix slows down this process. The IR spectra of the studied samples reveal the following main features of the silicate chains: a sharp absorption band at 465

  20. Low voltage varistor ceramics based on SnO2

    Indian Academy of Sciences (India)

    S R Dhage; V Ravi; O B Yang

    2007-12-01

    The nonlinear current ()–voltage () characteristics of tin dioxide doped with either Nb2O5 and CoO or Sb2O3 and CoO show promising values of nonlinear coefficient () values (∼11) with low breakdown voltages (B, ∼40 V mm-1). The pentavalent antimony or niobium acts as donor and increases the electronic conductivity. The crucial parameter for obtaining low breakdown voltage is the grain size, which depends upon sintering duration and temperature of these oxide ceramics.

  1. Corrosion of Silicon-Based Ceramics in Combustion Environments

    Science.gov (United States)

    Jacobson, Nathan S.

    1993-01-01

    The processes of passive oxidation, deposit-induced corrosion, active oxidation, scale/substance interactions, and scale volatility are presently studied in the case of high-purity SiC and Si3N4 in pure oxygen, giving attention to such secondary elements in the ceramics as water and CO2 oxidants, combustion environment impurities, and thermal cycling. Deposit-induced corrosion is discussed for the cases of NaSO4 as well as vanadate and oxide-slag deposits; issues associated with the active-to-passive oxidation transition are noted.

  2. Microstructure-electrical properties relation of zirconia based ceramic composites

    International Nuclear Information System (INIS)

    The electrical properties of zirconia based ceramic composites were studied by impedance spectroscopy. Three materials were prepared with different relative compositions of the conducting and insulating phases: (ZrO2:8 mol% Y2)3) + MgO, (ZrO2:8 mol% Y2O3) + Y2O3 and ZrO2 + 8 mol% Y2O3. All specimens were analyzed by X-ray diffraction and scanning electron microscopy for microstructural characterization and for correlation of microstructural aspects with electrical properties. For (ZrO2:8 mol% Y2O3) + MgO the main results show that the dependence of the different (microstructural constituents) contributions to the electrical resistivity on the magnesia content follows two stages: one below and another above the solubility limit of magnesia in Yttria-stabilized zirconia. The same dependence is found for the lattice parameter determined by X-ray diffraction measurements. The impedance diagrams of the composites have been resolved allowing the identification of contributions due to the presence of each microstructural constituent in both stages. Magnesia as a second phase is found to inhibit grain growth in Yttria-stabilized zirconia and the solubility limit for magnesia in the zirconia matrix is around 10 mol%. For (ZrO2:8 mol% Y2O3) + Y2O3 the main results show that: Yttria is present as a second phase for 1350 deg C /0.1 h sintering; the addition of 2 mol% of Yttria does not modify significantly the electrical properties; the solubility limit for Yttria is around 2 mol% according to electrical measurements. Similarly to magnesia, Yttria inhibits grain growth on Yttria-stabilized zirconia. The general effective medium theory was used to analyze the percolation of the insulating phase; the percolation threshold is different if one considers separately the total, bulk and grain boundary contributions to the electrical conductivity: 32.0, 38.5 and 27.8 vol% for total, intra and intergranular contributions, respectively. The increase of the activation energy for ionic

  3. Barium halide nanocrystals in fluorozirconate based glass ceramics for scintillation application

    International Nuclear Information System (INIS)

    Europium (Eu)-activated barium halide nanocrystals in fluorozirconate based glass ceramics represent a promising class of Xray scintillators. The scintillation in these glass ceramics is mainly caused by the emission of divalent Eu incorporated in hexagonal BaCl2 nanocrystals which are formed in the glass matrix upon appropriate annealing. Experiments with cerium (Ce)-activated fluorozironate glass ceramics showed that Ce is an interesting alternative. In order to get a better understanding of the scintillation mechanism in Eu- or Ce-activated barium halide nanocrystals, an investigation of the processes in the corresponding bulk material is essential. The objective of this thesis is the investigation of undoped, Eu-, and Ce-doped barium halides by X-ray excited luminescence (XL), pulse height, and scintillation decay spectra. That will help to figure out which of these crystals has the most promising scintillation properties and would be the best nanoparticles for the glass ceramics. Furthermore, alternative dopants like samarium (Sm) and manganese (Mn) were also investigated. Besides the above-mentioned optical investigation electron paramagnetic resonance (EPR) and Moessbauer measurements were carried out in order to complete the picture of Eu-doped barium halides. The EPR data of Eu-doped BaI2 is anticipated to yield more information about the crystal field and crystal structure that will help to understand the charge carrier process during the scintillation process. The main focus of the Moessbauer investigations was set on the Eu-doped fluorochlorozirconate glass ceramics. The results of this investigation should help to improve the glass ceramics. The Eu2+/Eu3+ ratio in the glass ceramics should be determined and optimize favor of the Eu2+. We also want to distinguish between Eu2+ in the glass matrix and Eu2+ in the nanocrystals. For a better understanding of Moessbauer spectroscopy on Eu also measurements on Eu in a CaF2 host lattice were carried out. (orig.)

  4. Key Durability Issues with Mullite-Based Environmental Barrier Coatings for Si-Based Ceramics

    Science.gov (United States)

    Lee, Kang N.

    2000-01-01

    Plasma-sprayed mullite (3Al2O3.2SiO2) and mullite/yttria-stabilized-zirconia (YSZ) dual layer coatings have been developed to protect silicon -based ceramics from environmental attack. Mullite-based coating systems show excellent durability in air. However, in combustion environments, corrosive species such as molten salt or water vapor penetrate through cracks in the coating and attack the Si-based ceramics along the interface. Thus the modification of the coating system for enhanced crack-resistance is necessary for long-term durability in combustion environments. Other key durability issues include interfacial contamination and coating/substrate bonding. Interfacial contamination leads to enhanced oxidation and interfacial pore formation, while a weak coating/substrate bonding leads to rapid attack of the interface by corrosive species, both of which can cause a premature failure of the coating. Interfacial contamination can be minimized by limiting impurities in coating and substrate materials. The interface may be modified to improve the coating/substrate bond.

  5. Dental ceramics: An update

    OpenAIRE

    Shenoy Arvind; Shenoy Nina

    2010-01-01

    In the last few decades, there have been tremendous advances in the mechanical properties and methods of fabrication of ceramic materials. While porcelain-based materials are still a major component of the market, there have been moves to replace metal ceramics systems with all ceramic systems. Advances in bonding techniques have increased the range and scope for use of ceramics in dentistry. In this brief review, we will discuss advances in ceramic materials and fabrication techniques. Examp...

  6. Tiled QR factorization algorithms

    CERN Document Server

    Bouwmeester, Henricus; Langou, Julien; Robert, Yves

    2011-01-01

    This work revisits existing algorithms for the QR factorization of rectangular matrices composed of p-by-q tiles, where p >= q. Within this framework, we study the critical paths and performance of algorithms such as Sameh and Kuck, Modi and Clarke, Greedy, and those found within PLASMA. Although neither Modi and Clarke nor Greedy is optimal, both are shown to be asymptotically optimal for all matrices of size p = q^2 f(q), where f is any function such that \\lim_{+\\infty} f= 0. This novel and important complexity result applies to all matrices where p and q are proportional, p = \\lambda q, with \\lambda >= 1, thereby encompassing many important situations in practice (least squares). We provide an extensive set of experiments that show the superiority of the new algorithms for tall matrices.

  7. Biomimetic synthesis of cellular SiC based ceramics from plant precursor

    Indian Academy of Sciences (India)

    O P Chakrabarti; H S Maiti; R Majumdar

    2004-10-01

    A novel biomimetic approach in designing and fabricating engineering ceramic materials has gained much interest in recent times. Following this approach, synthesis has been made of dense Si–SiC duplex ceramic composites and highly porous SiC ceramics in the image of the morphological features inherent in the caudex stem of a local monocotyledonous plant. The process route involves making of a carbonaceous biopreform and its subsequent reaction with an infiltrating silicon melt to yield the biomorphic Si–SiC ceramic composites with flexural strength and Young’s modulus of 264 MPa and 247 Gpa, respectively and loss in weight of only ∼ 9% during oxidative heating up to 1200°C in flowing air. The Si–SiC composites were transformed into porous (49 vol.%) SiC ceramics with complete preservation of microcellular anatomy of the parent plant, by depleting residual silicon phase in channel pores through reaction with carbon. SiC based materials so derived can be used in structural applications and in designing high temperature filters and catalyst supports.

  8. Preparation and Photocatalytic Property of TiO2/Diatomite-Based Porous Ceramics Composite Materials

    Directory of Open Access Journals (Sweden)

    Shuilin Zheng

    2012-01-01

    Full Text Available The diatomite-based porous ceramics was made by low-temperature sintering. Then the nano-TiO2/diatomite-based porous ceramics composite materials were prepared by hydrolysis deposition method with titanium tetrachloride as the precursor of TiO2 and diatomite-based porous as the supporting body of the nano-TiO2. The structure and microscopic appearance of nano-TiO2/diatomite-based porous ceramics composite materials was characterized by XRD and SEM. The photocatalytic property of the composite was investigated by the degradation of malachite green. Results showed that, after calcination at 550°C, TiO2 thin film loaded on the diatomite-based porous ceramics is anatase TiO2 and average grain size of TiO2 is about 10 nm. The degradation ratio of the composite for 5 mg/L malachite green solution reached 86.2% after irradiation for 6 h under ultraviolet.

  9. Tile-Based Fisher Ratio Analysis of Comprehensive Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry (GC × GC – TOFMS) Data using a Null Distribution Approach

    Energy Technology Data Exchange (ETDEWEB)

    Parsons, Brendon A.; Marney, Luke C.; Siegler, William C.; Hoggard, Jamin C.; Wright, Bob W.; Synovec, Robert E.

    2015-04-07

    Multi-dimensional chromatographic instrumentation produces information-rich, and chemically complex data containing meaningful chemical signals and/or chemical patterns. Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC – TOFMS) is a prominent instrumental platform that has been applied extensively for discovery-based experimentation, where samples are sufficiently volatile or amenable to derivatization. Use of GC × GC – TOFMS and associated data analysis strategies aim to uncover meaningful chemical signals or chemical patterns. However, for complex samples, meaningful chemical information is often buried in a background of less meaningful chemical signal and noise. In this report, we utilize the tile-based F-ratio software in concert with the standard addition method by spiking non-native chemicals into a diesel fuel matrix at low concentrations. While the previous work studied the concentration range of 100-1000 ppm, the current study focuses on the 0 ppm to 100 ppm analyte spike range. This study demonstrates the sensitivity and selectivity of the tile-based F-ratio software for discovery of true positives in the non-targeted analysis of a chemically complex and analytically challenging sample matrix. By exploring the low concentration spike levels, we gain a better understanding of the limit of detection (LOD) of the tile-based F-ratio software with GC × GC – TOFMS data.

  10. Current status of ceramic-based membranes for oxygen separation from air.

    Science.gov (United States)

    Hashim, Salwa Meredith; Mohamed, Abdul Rahman; Bhatia, Subhash

    2010-10-15

    There has been tremendous progress in membrane technology for gas separation, in particular oxygen separation from air in the last 20 years. It provides an alternative route to the existing conventional separation processes such as cryogenic distillation and pressure swing adsorption as well as cheaper production of oxygen with high purity. This review presents the recent advances of ceramic membranes for the separation of oxygen from air at high temperature. It covers the issues and problems with respect to the selectivity and separation performance. The paper also presents different approaches applied to overcome these challenges. The future directions of ceramic-based membranes for oxygen separation from air are also presented. PMID:20813344

  11. A small angle neutron scattering study of mica based glass-ceramics with applications in dentistry

    International Nuclear Information System (INIS)

    We are currently developing machinable and load-bearing mica-based glass-ceramics for use in restorative dental surgery. In this paper we present the results of an ambient temperature small angle neutron scattering (SANS) study of several such ceramics with chemical compositions chosen to optimise machinability and strength. The SANS spectra are all dominated by scattering from the crystalline-amorphous phase interface and exhibit Q-4 dependence (Porod scattering) indicating that, on a 100 A scale, the surface of the crystals is smooth

  12. A small angle neutron scattering study of mica based glass-ceramics with applications in dentistry

    Science.gov (United States)

    Kilcoyne, S. H.; Bentley, P. M.; Al-Jawad, M.; Bubb, N. L.; Al-Shammary, H. A. O.; Wood, D. J.

    2004-07-01

    We are currently developing machinable and load-bearing mica-based glass-ceramics for use in restorative dental surgery. In this paper we present the results of an ambient temperature small angle neutron scattering (SANS) study of several such ceramics with chemical compositions chosen to optimise machinability and strength. The SANS spectra are all dominated by scattering from the crystalline-amorphous phase interface and exhibit Q-4 dependence (Porod scattering) indicating that, on a 100Å scale, the surface of the crystals is smooth.

  13. A small angle neutron scattering study of mica based glass-ceramics with applications in dentistry

    Energy Technology Data Exchange (ETDEWEB)

    Kilcoyne, S.H.; Bentley, P.M.; Al-Jawad, M.; Bubb, N.L.; Al-Shammary, H.A.O.; Wood, D.J

    2004-07-15

    We are currently developing machinable and load-bearing mica-based glass-ceramics for use in restorative dental surgery. In this paper we present the results of an ambient temperature small angle neutron scattering (SANS) study of several such ceramics with chemical compositions chosen to optimise machinability and strength. The SANS spectra are all dominated by scattering from the crystalline-amorphous phase interface and exhibit Q{sup -4} dependence (Porod scattering) indicating that, on a 100 A scale, the surface of the crystals is smooth.

  14. The influence of γ-irradiation on electrophysical properties of spinel-based oxide ceramics

    International Nuclear Information System (INIS)

    The influence of 60Co γ-irradiation with 1.25 MeV average energy and 1 MGy absorbed dose on electrophysical properties of Cu-, Ni-, Co- and Mn-based spinel ceramic materials in the CuxNi1-x-yCo2yMn2-yO4 (0,1≤x≤0,8;0,1≤y≤0,9-x) system is investigated. The γ-induced increasing of the electrical resistance is observed for the investigated samples of various compositions. It is supposed that these changes are explained by cationic redistribution in the spinel sublattices of the ceramics

  15. Integrated thick-film p-i-p+ structures based on spinel ceramics

    OpenAIRE

    Klym, H.; Hadzaman, I.; Shpotyuk, O.; Q. Fu; Luo, W.; J. Deng

    2012-01-01

    Multilayered temperature/humidity sensitive thick-film p-i-p+ structures based on spinel-type semiconducting ceramics of different chemical composition Cu0.1Ni0.1Co1.6Mn1.2O4 (with p+-type of electrical conductivity), Cu0.1Ni0.8Co0.2Mn1.9O4 (with p-type of electrical conductivity) and magnesium aluminate i-type MgAl2O4 ceramics were fabricated and investigated. These structures are shown to be successfully applied for integrated environmental sensors.

  16. Structure and properties of ceramic preforms based on Al2O3 particles

    OpenAIRE

    L.A. Dobrzański; M. Kremzer; Nagel, A.

    2009-01-01

    Purpose: The main goal of this project is to elaborate and optimize the method of manufacturing the porous, ceramic preforms based on Al2O3 particles used as the reinforcement in order to produce modern metal matrix composites by pressure infiltration method with liquid metal alloys.Design/methodology/approach: Ceramic preforms were manufactured by the sintering method of Al2O3 powder with addition of pore forming agent. The preform material consists of powder Alcoa Al2O3 CL 2500, however, as...

  17. Ceramics based on titanium nitride and silicon nitride sintered by SPS-method

    Science.gov (United States)

    Sivkov, A. A.; Gerasimov, D. Yu; Evdokimov, A. A.

    2015-10-01

    The dependences of the microstructure and physical and mechanical properties of ceramic mixtures Si3N4/TiN in the full range of mass ratios of the components. Was also investigated directly, and the process of sintering occurring during a physical or chemical processes, in particular, has been obtained and the hardness of the material density on the ratio of the conductive titanium nitride phase and a silicon nitride insulating phase with values above and below the percolation threshold. Also obtained was pure ceramics based on titanium nitride with high physical-mechanical characteristics (H = 21.5 GPa).

  18. Crystal phase analysis of SnO2-based varistor ceramic using the Rietveld method

    International Nuclear Information System (INIS)

    A second addition of l mol% of CoO to a pre calcined SnO2-based ceramic doped with 1.0 mol% of CoO, 0.05 mol% of Nb2O5 and 0.05 mol% of Cr2O3 promotes the appearance of a secondary phase, Co2SnO4, besides the SnO2 cassiterite phase, when the ceramic was sintered at 1350 deg. C/2 h. This was observed using X-ray powder diffraction, scanning electron microscopy and energy dispersive X-ray techniques. Rietveld refinement was carried out to quantify the phases present in the ceramic system. The results of the quantitative analysis were 97 wt.% SnO2 and 3 wt.% Co2SnO4. The microstructural analysis showed that a certain amount of cobalt ion remains into cassiterite grains

  19. Synthesis and properties of MoSi2 based engineering ceramics

    Indian Academy of Sciences (India)

    P Srikari Tantri; Anup K Bhattacharya; Sheela K Ramasesha

    2001-10-01

    Molybdenum disilicide is a high temperature structural ceramic with many attractive properties for engineering applications. Foremost amongst these is its stability in corrosive atmospheres up to about 1600°C. However, there are a few undesirable properties that need to be addressed before it can become a viable material in high temperature applications. Since MoSi2 forms thermodynamically stable composites with both metals and ceramics, many reinforcing materials are incorporated into the matrix to improve the fracture toughness and creep properties. The low temperature oxidation can be controlled by making high density (> 95% of theoretical density) compacts. This article summarizes the important attempts that are made in improving the properties of molybdenum disilicide-based ceramics by the reinforcement with other materials.

  20. Experimental Study on LTCC Glass-Ceramic Based Dual Segment Cylindrical Dielectric Resonator Antenna

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Gangwar

    2013-01-01

    Full Text Available The measured characteristics in C/X bands, including material properties of a dual segment cylindrical dielectric resonator antenna (CDRA fabricated from glass-ceramic material based on B2O3–La2O3–MgO glass and La(Mg0.5Ti0.5O3 ceramic, are reported. The sintering characteristic of the ceramic in presence of glass is determined from contact angle measurement and DTA. The return loss and input impedance versus frequency characteristics and radiation patterns of CDRA at its resonant frequency of 6.31 GHz are studied. The measured results for resonant frequency and return loss bandwidth of the CDRA are also compared with corresponding theoretical ones.

  1. Sintering and thermal conductivity of AlN based ceramics containing refractory compounds

    International Nuclear Information System (INIS)

    Aluminum nitride based ceramics is a promising material for wear- and thermal resistant components. AlN matrix ceramics with dispersed hard materials was prepared by liquid-phase sintering using yttrium oxide Y2O3 as a consolidation aid. Vanadium carbide VC, tungsten carbide WC, chromium carbide Cr3C2, tungsten boride WB and titanium nitride TiN were used to reinforce the AlN ceramics. The AlN + 10 wt.% VC, AlN + 10 wt.% WC, AlN + 10 wt.% Cr3C2, AlN + 10 wt.% WB and AlN + 25 wt.% TiN composite powders were homogenized by planetary milling. The composite green compacts have been sintered at 1850 oC for 30 min in nitrogen to the relative density higher than 95 %. Thermal conductivity of the samples at room temperature was measured to be 78, 75, 80, 70 and 87 W/mK, respectively. (author)

  2. Tile-based Fisher ratio analysis of comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS) data using a null distribution approach.

    Science.gov (United States)

    Parsons, Brendon A; Marney, Luke C; Siegler, W Christopher; Hoggard, Jamin C; Wright, Bob W; Synovec, Robert E

    2015-04-01

    Comprehensive two-dimensional (2D) gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS) is a versatile instrumental platform capable of collecting highly informative, yet highly complex, chemical data for a variety of samples. Fisher-ratio (F-ratio) analysis applied to the supervised comparison of sample classes algorithmically reduces complex GC × GC-TOFMS data sets to find class distinguishing chemical features. F-ratio analysis, using a tile-based algorithm, significantly reduces the adverse effects of chromatographic misalignment and spurious covariance of the detected signal, enhancing the discovery of true positives while simultaneously reducing the likelihood of detecting false positives. Herein, we report a study using tile-based F-ratio analysis whereby four non-native analytes were spiked into diesel fuel at several concentrations ranging from 0 to 100 ppm. Spike level comparisons were performed in two regimes: comparing the spiked samples to the nonspiked fuel matrix and to each other at relative concentration factors of two. Redundant hits were algorithmically removed by refocusing the tiled results onto the original high resolution pixel level data. To objectively limit the tile-based F-ratio results to only features which are statistically likely to be true positives, we developed a combinatorial technique using null class comparisons, called null distribution analysis, by which we determined a statistically defensible F-ratio cutoff for the analysis of the hit list. After applying null distribution analysis, spiked analytes were reliably discovered at ∼1 to ∼10 ppm (∼5 to ∼50 pg using a 200:1 split), depending upon the degree of mass spectral selectivity and 2D chromatographic resolution, with minimal occurrence of false positives. To place the relevance of this work among other methods in this field, results are compared to those for pixel and peak table-based approaches. PMID:25785933

  3. Signed shape tilings of squares

    OpenAIRE

    Keating, Kevin

    1998-01-01

    Let T be a tile in the Cartesian plane made up of finitely many rectangles whose corners have rational coordinates and whose sides are parallel to the coordinate axes. This paper gives necessary and sufficient conditions for a square to be tilable by finitely many \\Q-weighted tiles with the same shape as T, and necessary and sufficient conditions for a square to be tilable by finitely many \\Z-weighted tiles with the same shape as T. The main tool we use is a variant of F. W. Barnes's algebrai...

  4. Calcium carbonate decomposition in white-body tiles during firing in the presence of carbon dioxide

    OpenAIRE

    Escardino Benlloch, Agustín; Gómez Tena, María Pilar; Feliu Mingarro, Carlos; García Ten, Francisco Javier; Saburit Llaudis, Alejandro

    2013-01-01

    This study examines the thermal decomposition process of the calcium carbonate (calcite powder) contained in test pieces of porous ceramics, of the same composition as that used in manufacturing ceramic wall tile bodies, in the presence of carbon dioxide, in the temperature range 1123–1223 K. The experiments were carried out in a tubular reactor, under isothermal conditions, in a gas stream comprising different concentrations of air and carbon dioxide. Assuming that the relationship betwe...

  5. The DigiTile Project. Conceiving, Computing and Creating Contemporary Tiling Prototypes

    NARCIS (Netherlands)

    Breen, J.L.H.; Stellingwerff, M.C.

    2007-01-01

    The influx of computer-based design and presentation platforms, particularly in conjunction with computer aided physical modelling and manufacturing techniques, has stimulated a renewed focus on imaginative, innovative architectural product design. Essentially, the ambition of the DigiTile exercise

  6. Engineering spinal fusion: evaluating ceramic materials for cell based tissue engineered approaches

    NARCIS (Netherlands)

    Wilson, C.E.

    2011-01-01

    The principal aim of this thesis was to advance the development of tissue engineered posterolateral spinal fusion by investigating the potential of calcium phosphate ceramic materials to support cell based tissue engineered bone formation. This was accomplished by developing several novel model syst

  7. Sintering of SnO2-based ceramics and corrosion behaviour in molten glasses

    International Nuclear Information System (INIS)

    With regards to their good mechanical properties and their interesting oxidation behaviour at high temperatures, SnO2-based ceramics can be used, for example, for electrodes heating in the glass industry or, more specially, in nuclear waste melting furnaces. In the working conditions where these materials can be in direct contact with metallic pieces at temperature higher than 700 deg. C, the using of additives such as ZrO2 seems to be necessary in order to reduce the tin activity in SnO2 by dilution of tin by Zr. Consequently, in the first part, the role of zirconium additions on the natural sintering process of SnO2-based ceramics has been identified between 1100 and 1200 deg. C. The densification and grain growth mechanisms have been elucidated for Sn1-xZrxO2 materials for small additions of zirconia and cobalt monoxide which is well known to favour the densification process of tin dioxide. In a second part, some corrosion tests of SnO2-based ceramics in a molten glass for long times at temperatures higher than 1200 deg. C were performed. These results indicated a low ceramic dissolution and glass intergranular penetration for the most severe conditions. In comparison with the metallic materials, the corrosion rate recorded for SnO2-based materials in the most severe conditions seems to be low. (authors)

  8. THE USE OF FLY ASH IN THE PRODUCTION OF SIALON BASED STRUCTURAL CERAMICS

    Science.gov (United States)

    EPA GRANT NUMBER: X832541C004Title: The Use of Fly Ash in the Production of SiAlON based Structural CeramicsInvestigator: James R. VarnerInstitution: Alfred UniversityEPA Project Officer: S. Bala KrishnanProject Perio...

  9. Method for improving the toughness of silicon carbide-based ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Tein, Tseng-Ying (Ann Arbor, MI); Hilmas, Gregory E. (Dexter, MI)

    1996-01-01

    Method of improving the toughness of SiC-based ceramics. SiC, , AlN, Al.sub.2 O.sub.3 and optionally .alpha.-Si.sub.3 N.sub.4 are hot pressed to form a material which includes AlN polytypoids within its structure.

  10. Corrosion Behavior of SnO2-based Electrode Ceramics in Soda-lime Glass Liquid

    International Nuclear Information System (INIS)

    Dense SnO2-based electrode ceramics have extensive application prospect in glass electric-melting industry due to the excellent electrically-conductive and chemical property in high temperatures and oxidation environment. In this paper, dense SnO2-based electrode ceramics doped with MnO2 and Sb2O3 were prepared by pressureless sintering method and the corrosion rate in soda-lime glass liquid as well as the microstructure evolution was mainly investigated. The results suggested that SnO2-based ceramics had good corrosion resistance, and the minimum value was only 2.54x10-4 mm/h when MnO2 content is 1.0% and Sb2O3 content is 0.1%. Composition Elements of Glass liquid were detected in the grain boundary and some intergranular pores. It was found that SnO2 grains remained unchanged, whereas MnO2 was easily dissolved into molten glass liquid. SnO2-based electrode ceramics with dense structure and few amounts of additives had excellent corrosion resistance to the molten glass.

  11. Lacunae infills for in situ treatment of historic glazed tiles

    Science.gov (United States)

    Mendes, Marta T.; Esteves, Lurdes; Ferreira, Teresa A.; Candeias, António; Tennent, Norman H.; Rodrigues, José Delgado; Pereira, Sílvia R. M.

    2016-05-01

    Knowledge of current conservation materials and methods together with those adopted in the past is essential to aid research and improve or develop better conservation options. The infill and painting of tile lacunae are subjected to special requirements mainly when used in outdoor settings. A selection of the most commonly used materials was undertaken and performed based on inquiries to practitioners working in the field. The infill pastes comprised organic (epoxy, polyester), inorganic (slaked lime, hydraulic lime and zinc hydroxychloride) and mixed organic-inorganic (slaked lime mixed with a vinylic resin) binders. The selected aggregates were those most commonly used or those already present in the commercially formulated products. The infill pastes were characterised by SEM, MIP, open porosity, water absorption by capillarity, water vapour permeability, thermal and hydric expansibilities and adhesion to the ceramic body. Their performance was assessed after curing, artificial ageing (salt ageing and UV-Temp-RH cycles) and natural ageing. The results were interpreted in terms of their significance as indicators of effectiveness, compatibility and durability.

  12. Characterization of avian eggshell waste aiming its use in a ceramic wall tile paste Caracterização de resíduo de casca de ovo visando seu aproveitamento em revestimento cerâmico poroso

    Directory of Open Access Journals (Sweden)

    M. N. Freire

    2006-12-01

    Full Text Available In Brazil, the food industry generates every year huge amounts of avian eggshell waste, and a critical question is to find an adequate use for this waste. The aim of this work is to determine the chemical, mineralogical and physical characteristics of a nonprocessed avian eggshell waste sample, as well as to investigate its use in wall tile paste. The sample was analyzed regarding to chemical composition, X-ray diffraction, morphology, particle size analysis, density, organic matter, soluble salts, and thermal analysis. The results indicated that the eggshell waste sample rich in CaCO3 can be used as an alternative raw material in the production of wall tile materials.No Brasil a indústria alimentícia gera enormes quantidades de resíduo de casca de ovo galináceo todo ano, e uma questão crítica é estabelecer um uso adequado para este resíduo. O objetivo deste trabalho é estudar as características química, mineralógica e física de uma amostra de resíduo de casca de ovo natural, bem como avaliar sua utilização em revestimento cerâmico poroso. A amostra de resíduo de casca de ovo foi caracterizada com relação à composição química, difração de raios X, morfologia, análise de tamanho de partícula, massa específica, matéria orgânica, sais solúveis e análise térmica. Os resultados mostraram que o resíduo de casca de ovo rico em CaCO3 pode ser usado como uma matéria-prima alternativa na produção de revestimento cerâmico poroso (azulejo.

  13. Utilisation of Spark Plasma Sintering for joining of advanced SiC-based ceramics for aerospace applications

    Czech Academy of Sciences Publication Activity Database

    Tatarko, P.; Saunders, T.; Chlup, Zdeněk; Dlouhý, Ivo; Reece, M. J.

    Toledo: ECERS, 2015. ISBN 978-84-606-9257-7. [ECERS 14 - International Conference of the European Ceramic Society /14./. 21.06.2015-25.06.2015, Toledo] Institutional support: RVO:68081723 Keywords : Spark Plasma Sintering * joining * SiC-based ceramics Subject RIV: JL - Materials Fatigue, Friction Mechanics

  14. Structure and properties of ceramic preforms based on Al2O3 particles

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2009-07-01

    Full Text Available Purpose: The main goal of this project is to elaborate and optimize the method of manufacturing the porous, ceramic preforms based on Al2O3 particles used as the reinforcement in order to produce modern metal matrix composites by pressure infiltration method with liquid metal alloys.Design/methodology/approach: Ceramic preforms were manufactured by the sintering method of Al2O3 powder with addition of pore forming agent. The preform material consists of powder Alcoa Al2O3 CL 2500, however, as the forming factor of the structure of canals and pores inside the ceramic, agglomerated framework the carbon fibres Sigrafil C10 M250 UNS were used. The addition of carbon fibres was 30, 40 and 50% of weight. The TGA analysis of carbon fibres has been made. The investigations of the structure of powder Al2O3 Alcoa CL 2500, the used carbon fibres and the obtained ceramic preforms on the scanning electron microscope (SEM have been made. The measurement of permeability of the obtained materials on the specially designed station has also been made.Findings: The obtained preforms are characterized by volumetric participation of ceramic phase of 15-31%, what is the result of differential addition of the pores forming agent, and the high permeability indicates on “the open porosity”.Research limitations/implications: The basic limit of the mentioned method is the possibility of obtaining preforms of porosity less than 85%, where in case of using the ceramic fibres the pores can be more than 90% of material volumetric.Practical implications: The manufactured ceramic preforms are widely used as the reinforcement to produce the composite materials by the infiltration method. That method allows manufacturing the metal elements locally reinforced and the near-net shape composite products.Originality/value: The received results show the possibility of obtaining the new preforms being the cheaper alternative for semi-finished products based on the ceramic fibres and

  15. A Homeomorphism Invariant for Substitution Tiling Spaces

    OpenAIRE

    Ormes, Nic; Radin, Charles; Sadun, Lorenzo

    2000-01-01

    We derive a homeomorphism invariant for those tiling spaces which are made by rather general substitution rules on polygonal tiles, including those tilings, like the pinwheel, which contain tiles in infinitely many orientations. The invariant is a quotient of Cech cohomology, is easily computed directly from the substitution rule, and distinguishes many examples, including most pinwheel-like tiling spaces. We also introduce a module structure on cohomology which is very convenient as well as ...

  16. A Tale of Two Tilings

    OpenAIRE

    Glotzer, Sharon C.; Keys, Aaron S.

    2010-01-01

    What do you get when you cross a crystal with a quasicrystal? The surprising answer stretches from Fibonacci to Kepler, who nearly 400 years ago showed how the ancient tiles of Archimedes form periodic patterns.

  17. Industrial ceramics - Properties, forming and applications

    International Nuclear Information System (INIS)

    After a general introduction to ceramics (definition, general properties, elaboration, applications, market data), this book address conventional ceramics (elaboration, material types), thermo-structural ceramics (oxide based ceramics, non-oxide ceramics, fields of application, functional coatings), refractory ceramics, long fibre and ceramic matrix composites, carbonaceous materials, ceramics used for filtration, catalysis and the environment, ceramics for biomedical applications, ceramics for electronics and electrical engineering (for capacitors, magnetic, piezoelectric, dielectric ceramics, ceramics for hyper-frequency resonators), electrochemical ceramics, transparent ceramics (forming and sintering), glasses, mineral binders. The last chapter addresses ceramics used in the nuclear energy sector: in nuclear fuels and fissile material, absorbing ceramics and shields, in the management of nuclear wastes, new ceramics for reactors under construction or for future nuclear energy

  18. Nine Tiles Model Construction and Cache of CGML in Mobile

    Directory of Open Access Journals (Sweden)

    Aiguo Zhang

    2015-01-01

    Full Text Available Document management is a usual way to organize spatial data in mobile terminals. And the compressed CGML spatial data has been widely used in location based services. Referring to the thoughts of map set in cartography, nine closely connected and equal sized rectangles are used as the scope for requesting mobile map data, and these nine closely connected rectangles are built to be nine tiles model. Therefore, in view of the method of block requesting and storing on mobile spatial data following nine tiles model, as well as the large quantity of mobile spatial data and its complex geometry relation, this paper puts forward the construction mechanism of nine tiles model and cache organization of CGML spatial data in mobile terminals that abide by nine tiles model. This way of organization and management of mobile spatial data is good to increase the efficiency of heavy spatial data accessing in the low band and reliability of wireless network environment.

  19. Lozenge Tilings and Hurwitz Numbers

    Science.gov (United States)

    Novak, Jonathan

    2015-10-01

    We give a new proof of the fact that, near a turning point of the frozen boundary, the vertical tiles in a uniformly random lozenge tiling of a large sawtooth domain are distributed like the eigenvalues of a GUE random matrix. Our argument uses none of the standard tools of integrable probability. In their place, it uses a combinatorial interpretation of the Harish-Chandra/Itzykson-Zuber integral as a generating function for desymmetrized Hurwitz numbers.

  20. Tiling Spaces are Inverse Limits

    OpenAIRE

    Sadun, Lorenzo

    2002-01-01

    Let M be an arbitrary Riemannian homogeneous space, and let Omega be a space of tilings of M, with finite local complexity (relative to some symmetry group Gamma) and closed in the natural topology. Then Omega is the inverse limit of a sequence of compact finite-dimensional branched manifolds. The branched manifolds are (finite) unions of cells, constructed from the tiles themselves and the group Gamma. This result extends previous results of Anderson and Putnam, of Ormes, Radin and Sadun, of...

  1. Influence de la nature chimique et minéralogique des argiles et du processus de fabrication sur la qualité des carreaux céramiques Influence of chemical and mineralogical nature of clay and manufacturing process on the quality of ceramic tiles

    Directory of Open Access Journals (Sweden)

    Sadik C.

    2012-09-01

    Full Text Available La présente étude correspond à une approche pluridisciplinaire menée en étroite collaboration entre des géologues, des chimistes et des industriels de la céramique. Les résultats confirment l’étroite relation existante entre la composition des argiles et la qualité du produit céramique final. Les briquettes obtenues, dans les mêmes conditions, à partir de deux argiles marocaines assez différentes du point de vue chimique et minéralogique, présentent des caractéristiques technologiques bien distinctes. l’utilisation d’adjuvants minéraux, bien sélectionnés, contribue à l’équilibrage des argiles brutes et conduit à une nette amélioration de la qualité du produit céramique, notamment une réduction de leur retrait à la cuisson et une augmentation de leur résistance à la flexion. Concernant l’effet du processus de fabrication, l’application de l’engobe et de l’émail, s’avère être à l’origine de bombement des carreaux lors de la cuisson, en raison vraisemblablement de la différence des coefficients de dilatation des deux milieux argile et émail. This study is conducted in a multidisciplinary collaboration between geologists, chemists and industrial ceramics. The results confirm the close ralatioship existing between the composition of clays and quality of the finished ceramic pieces. The obtained specimens, under the same conditions, from two moroccan clays that are different on the chimico-mineralogical point of view, present distinct technological characteristics. The use of well selected mineral adjuvants, contributes to the balancing of raw clays and leads to a marked improvement in the quality of the ceramic product, including a reduction on their firing shrinkage and an increase of flexural strength. Concerning the effect of the manufacturing process, the application of the glaze, turns out to be the cause of bulging tiles during firing, probably because of the difference in thermal

  2. Rational self-affine tiles

    CERN Document Server

    Steiner, Wolfgang

    2012-01-01

    An integral self-affine tile is the solution of a set equation $\\mathbf{A} \\mathcal{T} = \\bigcup_{d \\in \\mathcal{D}} (\\mathcal{T} + d)$, where $\\mathbf{A}$ is an $n \\times n$ integer matrix and $\\mathcal{D}$ is a finite subset of $\\mathbb{Z}^n$. In the recent decades, these objects and the induced tilings have been studied systematically. We extend this theory to matrices $\\mathbf{A} \\in \\mathbb{Q}^{n \\times n}$. We define rational self-affine tiles as compact subsets of the open subring $\\mathbb{R}^n\\times \\prod_\\mathfrak{p} K_\\mathfrak{p}$ of the ad\\'ele ring $\\mathbb{A}_K$, where the factors of the (finite) product are certain $\\mathfrak{p}$-adic completions of a number field $K$ that is defined in terms of the characteristic polynomial of $\\mathbf{A}$. Employing methods from classical algebraic number theory, Fourier analysis in number fields, and results on zero sets of transfer operators, we establish a general tiling theorem for these tiles. We also associate a second kind of tiles with a rational matr...

  3. Lithography-based ceramic manufacture (LCM) of auxetic structures: present capabilities and challenges

    Science.gov (United States)

    Díaz Lantada, Andrés; de Blas Romero, Adrián; Schwentenwein, Martin; Jellinek, Christopher; Homa, Johannes

    2016-05-01

    Auxetic metamaterials are known for having a negative Poisson’s ratio (NPR) and for displaying the unexpected properties of lateral expansion when stretched and densification when compressed. Even though a wide set of micro-manufacturing resources have been used for the development of auxetic metamaterials and related devices, additional precision and an extension to other families of materials is needed for their industrial expansion. In addition, their manufacture using ceramic materials is still challenging. In this study we present a very promising approach for the development of auxetic metamaterials and devices based on the use of lithography-based ceramic manufacturing. The process stands out for its precision and complex three-dimensional geometries attainable, without the need of supporting structures, and for enabling the manufacture of ceramic auxetics with their geometry controlled from the design stage with micrometric precision. To our knowledge it represents the first example of application of this technology to the manufacture of auxetic geometries using ceramic materials. We have used a special three-dimensional auxetic design whose remarkable NPR has been previously highlighted.

  4. Regional ceramic production and distribution systems during the late intermediate ceramic period in central Chile based on NAA

    International Nuclear Information System (INIS)

    This research focused on the pre-Hispanic ceramic production and distribution systems of the Maipo region in central Chile by means of determining the concentration of the chemical elements in pottery of the Aconcagua culture (900-1450 A.D.) with instrumental neutron activation analysis (INAA). Pottery fragments from eight archaeological sites and natural clays from the study region were included. The differences in chemical composition between subsets of the sample (sites, paste group and ceramic type) were interpreted as indicators of resource and ceramic production locations as well as the imprint of the geological background. These results contributed to the understanding of the Aconcagua ceramic assemblage and helped to test some hypotheses about the Aconcagua social organization. (author)

  5. The lack of homogeneity in the product (LHP) in the ceramic tile industry and its impact on the reallocation of inventories; La falta de homogeneidad del producto (FHP) en las empresas ceramicas y su impacto en la reasignacion del inventario

    Energy Technology Data Exchange (ETDEWEB)

    Alarcon, F.; Alemany, M. M. E.; Lario, F. C.; Oltra, R. F.

    2011-07-01

    The allocation of the product available- to-promise (ATP) in make-to-stock (MTS) contexts is of the utmost importance as it can influence customer satisfaction and profits of the company. However, a proper initial allocation may become inadequate for several reasons. In these case, it is necessary the reallocation of inventory, which will be more complex the more ambitious goals to achieve with it and increased the amount of information to use. In this regard, it is noteworthy that the lack of homogeneity in the product (LHP), present in different industrial sectors, causes the atomization of the inventory and increases the complexity of the reallocation, difficult to obtain optimal solutions. This paper describes the problems of the LHP, first under a generic perspective and then, particularized to MTS ceramic companies. Subsequently, situations in which a specific allocation of ATP can no longer be appropriate in this context are identified and the reassignment, as a way to search for new valid assignments, is proposed. Finally, through a case study of a ceramic company, the impact of the LHP in each of the situations identified is analyzed, noting that the LHP causes some of these situations and in all of them, complicates the reallocation of inventory to orders. (Authors) 31 refs.

  6. Large TileCal magnetic field simulation

    International Nuclear Information System (INIS)

    The ATLAS magnetic field map has been estimated in the presence of the hadron tile calorimeter. This is an important issue in order to quantify the needs for individual PMT shielding, the effect on the scintillator light yield and its implications on the calibration. The field source is based on a central solenoid and 8 superconducting air-core toroidal coils. The maximum induction value in the scintillating tiles does not exceed 6 mT. When an iron plate is used to close the open drawer window the field inside the PMT near to the extended barrel edge does not exceed 0.6 mT. Estimation of ponder motive force distribution, acting on individual units of the system was performed. VF electromagnetic software OPERA-TOSCA and CERN POISCR code were used for the field simulation of the system. 10 refs., 4 figs

  7. Milestone 5 test report. Task 5, subtask 5.2: Tile to foam strength tests

    Science.gov (United States)

    Greenberg, H. S.

    1994-12-01

    This report summarizes work that has been performed to date on the strength of a cryotank insulation system using Rohacell foam and TUFI-coated AETB-12 ceramic tiles directly bonded to a simulated graphite-epoxy tank wall. Testing utilized a custom specimen design which consists of a long tensile specimen with eccentric loading to induce curvature similar to the curvature expected due to 'pillowing' of the tank when pressurized. A finite element model was constructed to predict the specific element strains in the test article, and to assist with design of the test specimen to meet the specific goals of curvature and laminate strain. The results indicate that the heat treated 3.25-pcf density Rohacell foam does not provide sufficient strength for the induced stresses due to curvature and stress concentration at the RTV bondline to the TUFI tile. The test was repeated using higher density non-heat treated Rohacell foam (6.9 pcf) without foam failure. The finite element model was shown to predict specimen behavior, and validation of the model was successful. It is pertinent to mention that the analyses described herein accurately predicted the failure of the heat treated foams and based on this analysis method it is expected that the untreated 3.25 pcf Rohacell foam will be successful.

  8. Effect of ceramic thickness and composite bases on stress distribution of inlays--a finite element analysis.

    Science.gov (United States)

    Durand, Letícia Brandão; Guimarães, Jackeline Coutinho; Monteiro Junior, Sylvio; Baratieri, Luiz Narciso

    2015-01-01

    The purpose of this study was to determine the effect of cavity depth, ceramic thickness, and resin bases with different elastic modulus on von Mises stress patterns of ceramic inlays. Tridimensional geometric models were developed with SolidWorks image software. The differences between the models were: depth of pulpal wall, ceramic thickness, and presence of composite bases with different thickness and elastic modulus. The geometric models were constrained at the proximal surfaces and base of maxillary bone. A load of 100 N was applied. The stress distribution pattern was analyzed with von Mises stress diagrams. The maximum von Mises stress values ranged from 176 MPa to 263 MPa and varied among the 3D-models. The highest von Mises stress value was found on models with 1-mm-thick composite resin base and 1-mm-thick ceramic inlay. Intermediate values (249-250 MPa) occurred on models with 2-mm-thick composite resin base and 1-mm-thick ceramic inlay and 1-mm-thick composite resin base and 2-mm-thick ceramic inlay. The lowest values were observed on models restored exclusively with ceramic inlay (176 MPa to 182 MPa). It was found that thicker inlays distribute stress more favorably and bases with low elastic modulus increase stress concentrations on the internal surface of the ceramic inlay. The increase of ceramic thickness tends to present more favorable stress distribution, especially when bonded directly onto the cavity without the use of supporting materials. When the use of a composite base is required, composite resin with high elastic modulus and reduced thickness should be preferred. PMID:25831105

  9. Ceramics manufacturing contributes to ambient silica air pollution and burden of lung disease.

    Science.gov (United States)

    Liao, Chung-Min; Wu, Bo-Chun; Cheng, Yi-Hsien; You, Shu-Han; Lin, Yi-Jun; Hsieh, Nan-Hung

    2015-10-01

    Inhalation of silica (SiO2) in occupational exposures can cause pulmonary fibrosis (silicosis), lung function deficits, pulmonary inflammation, and lung cancer. Current risk assessment models, however, cannot fully explain the magnitude of silica-induced pulmonary disease risk. The purpose of this study was to assess human health risk exposed to airborne silica dust in Taiwan ceramics manufacturing. We conducted measurements to characterize workplace-specific airborne silica dust in tile and commodity ceramic factories and used physiologically based alveolar exposure model to estimate exposure dose. We constructed dose-response models for describing relationships between exposure dose and inflammatory responses, by which health risks among workers can be assessed. We found that silica contents were 0.22-33.04 % with mean concentration ranges of 0.11-5.48 and 0.46-1763.30 μg m(-3), respectively, in commodity and tile ceramic factories. We showed that granulation workers in tile ceramic factory had the highest total SiO2 lung burden (∼1000 mg) with cumulative SiO2 lung burden of ∼4 × 10(4) mg-year. The threshold estimates with an effect on human lung inflammation and fibrosis are 407.31 ± 277.10 (mean ± sd) and 505.91 ± 231.69 mg, respectively. For granulation workers, long-term exposure to airborne silica dust for 30-45 years was likely to pose severe adverse health risks of inflammation and fibrosis. We provide integrated assessment algorithms required to implement the analyses and maintain resulting concentration of silica dust at safety threshold level in the hope that they will stimulate further analyses and interpretation. We suggest that decision-makers take action to implement platforms for effective risk management to prevent the related long-term occupational disease in ceramics manufacturing. PMID:26002365

  10. Statistical design for recycling kaolin processing waste in the manufacturing of mullite-based ceramics

    OpenAIRE

    Romualdo Rodrigues Menezes; Maria Isabel Brasileiro; Wherllyson Patricio Gonçalves; Lisiane Navarro de Lima Santana; Gelmires de Araújo Neves; Heber Sivini Ferreira; Heber Carlos Ferreira

    2009-01-01

    Mineral extraction and processing industries have been cited as sources of environmental contamination and pollution. However, waste recycling represents an alternative recovery option, which is interesting from an environmental and economic standpoint. In this work, recycling of kaolin processing waste in the manufacture of mullite-based ceramics was investigated based on the statistical design of mixture experiments methodology. Ten formulations using kaolin processing waste, alumina and ba...

  11. Ni-BaTiO3-Based Base-Metal Electrode (BME) Ceramic Capacitors for Space Applications

    Science.gov (United States)

    Liu, Donhang; Fetter, Lula; Meinhold, Bruce

    2015-01-01

    A multi-layer ceramic capacitor (MLCC) is a high-temperature (1350C typical) co-fired ceramic monolithic that is composed of many layers of alternately stacked oxide-based dielectric and internal metal electrodes. To make the dielectric layers insulating and the metal electrode layers conducting, only highly oxidation-resistant precious metals, such as platinum, palladium, and silver, can be used for the co-firing of insulating MLCCs in a regular air atmosphere. MLCCs made with precious metals as internal electrodes and terminations are called precious-metal electrode (PME) capacitors. Currently, all military and space-level applications only address the use of PME capacitors.

  12. Synthesis and ceramic processing of alumina and zirconia based composites infiltrated with glass phase for dental applications

    International Nuclear Information System (INIS)

    The interest for the use of ceramic materials for dental applications started due to the good aesthetic appearance promoted by the similarity to natural teeth. However, the fragility of traditional ceramics was a limitation for their use in stress conditions. The development of alumina and zirconia based materials, that associate aesthetic results, biocompatibility and good mechanical behaviour, makes possible the employment of ceramics for fabrication of dental restorations. The incorporation of vitreous phase in these ceramics is an alternative to minimize the ceramic retraction and to improve the adhesion to resin-based cements, necessary for the union of ceramic frameworks to the remaining dental structure. In the dentistry field, alumina and zirconia ceramic infiltrated with glassy phase are represented commercially by the In-Ceram systems. Considering that the improvement of powder's synthesis routes and of techniques of ceramic processing contributes for good performance of these materials, the goal of the present work is the study of processing conditions of alumina and/or 3 mol% yttria-stabilized zirconia ceramics infiltrated with aluminum borosilicate lanthanum glass. The powders, synthesized by hydroxide coprecipitation route, were pressed by uniaxial compaction and pre-sintered at temperature range between 950 and 1650 degree C in order to obtain porous ceramics bodies. Vitreous phase incorporation was performed by impregnation of aluminum borosilicate lanthanum powder, also prepared in this work, followed by heat treatment between 1200 and 1400 degree C .Ceramic powders were characterized by thermogravimetry, X-ray diffraction, scanning and transmission electron microscopy, gaseous adsorption (BET) and laser diffraction. Sinterability of alumina and /or stabilized zirconia green pellets was evaluated by dilatometry. Pre-sintered ceramics were characterized by apparent density measurements (Archimedes method), X-ray diffraction and scanning electron

  13. Radon-222 Study in Ceramics and Indoor Air

    International Nuclear Information System (INIS)

    A total 50 samples of 13 different ceramic tiles companies collected from the Egyptian market for the measurements of radon exhalation rate. Three homes include twenty rooms were selected. The period of the survey was in range 2-3 months for homes for each season while it was about 15 days for ceramic tiles. The radon exhalation rate of ceramic tiles (clay and glaze) and indoor radon activity concentration were measured by alpha tracks technique. The average radon exhalation rate in three homes was observed to be in the range 2.2-5.2 mBq.m-2.h-1. The average of Ra-226 activity for all ceramic tiles either the floor or wall tile is in the range 16-64 Bq.kg-1. The porosity of ceramic tiles is found in the range 0.19-0.29. The effective dose in all rooms is found in the range 0.9- 1.3 mSv.y-1 .

  14. MIJ2K: Enhanced video transmission based on conditional replenishment of JPEG2000 tiles with motion compensation

    OpenAIRE

    Luis Bustamante, Álvaro; Molina, José M.; Patricio Guisado, Miguel Ángel

    2011-01-01

    A video compressed as a sequence of JPEG2000 images can achieve the scalability, flexibility, and accessibility that is lacking in current predictive motion-compensated video coding standards. However, streaming JPEG2000-based sequences would consume considerably more bandwidth. With the aim of solving this problem, this paper describes a new patent pending method, called MIJ2K. MIJ2K reduces the inter-frame redundancy present in common JPEG2000 sequences (also called MJP2). We apply a ...

  15. Numerical study of internal load transfer in metal/ceramic composites based on freeze-cast ceramic preforms and experimental validation

    International Nuclear Information System (INIS)

    The elastic–plastic deformation and internal load transfer in metal/ceramic composites are studied in this work both numerically and experimentally. The composite was fabricated by squeeze-casting AlSi12 melt in an open porous preform made by freeze-casting and drying of alumina suspension. Such composites exhibit a complex microstructure composed of lamellar domains. Single-domain samples were extracted from bulk material. Uniaxial compression tests were carried out parallel to the direction of the alternating metallic alloy and ceramic lamellae in the plane normal to the direction of freeze-casting. This loading mode is selected as highest load transfer occurs when loaded along the ceramic lamellae. Numerical modeling was done using the finite element method using quasi-3D microstructure based on metallographic 2D section and a modified Voigt homogenization technique assuming plastic behavior of the metallic alloy, absence of any damage and ideal interface between the phases. Internal load transfer mechanism was predicted for composites with different ceramic volume fractions. Results show that at any applied stress, as the ceramic content increases, the phase stress in alumina along the loading direction continuously decreases. Experimental validation of the numerical results is carried out by in-situ compression test along with energy dispersive synchrotron X-ray diffraction in one sample with 41 vol% ceramic. Results show that both the numerical techniques yield similar results, which match well with the experimental measurements. The ratio of the phase stress to the applied stress in alumina reaches a highest value between 2 and 2.5 up to a compressive stress of about 300 MPa. At higher applied stresses both the experimentally determined lattice microstrain and the phase stress along the loading direction in alumina decrease due to the initiation of possible damage. This study shows that the applied economic and more flexible homogenization technique is a

  16. The Tile-map Based Vulnerability Assessment Code of a Physical Protection System: SAPE (Systematic Analysis of Protection Effectiveness)

    International Nuclear Information System (INIS)

    Increasing threats on nuclear facilities demands stronger physical protection system (PPS) within the limited budget. For this reason we need an efficient physical protection system and before making an efficient PPS we need to evaluate it. This evaluation process should faithfully reflect real situation, reveal weak points and unnecessary protection elements, and give comparable quantitative values. Performance based analysis helps to build an efficient physical protection system. Instead of regulating the number of sensors and barriers, the performance based analysis evaluates a PPS fit to the situation of a facility. The analysis assesses delay (sensors) and detection (barriers) of a PPS against an intrusion, and judges whether a response force arrives before intruders complete their job. Performance based analysis needs complicated calculation and, hence, several assessment codes have been developed. A code called the estimation of adversary sequence interruption (EASI) was developed to analyze vulnerability along a single intrusion path. The systematic analysis of vulnerability to intrusion (SAVI) code investigates multi-paths to a valuable asset in an actual facility. SAVI uses adversary sequence diagram to describe multi-paths

  17. Boron-containing neutron shielding building ceramics

    International Nuclear Information System (INIS)

    The data are presented on the composition of raw materials as well as on the properties and chemical composition of finished products of ceramics intended for neutron shielding. It is shown that 0.8 % content of B2O3 in bricks of ceramic mass proposed halves neutron radiation from the source of 106 neutr·s-1 close rate compared to bricks of boron free ceramic mass. Results of tests on water absorption and compression strength make it possible to recommend new ceramics to be used as tiles and facade building materials

  18. Dental ceramics: An update

    Directory of Open Access Journals (Sweden)

    Shenoy Arvind

    2010-01-01

    Full Text Available In the last few decades, there have been tremendous advances in the mechanical properties and methods of fabrication of ceramic materials. While porcelain-based materials are still a major component of the market, there have been moves to replace metal ceramics systems with all ceramic systems. Advances in bonding techniques have increased the range and scope for use of ceramics in dentistry. In this brief review, we will discuss advances in ceramic materials and fabrication techniques. Examples of the microstructure property relationships for these ceramic materials will also be addressed.

  19. Dyck tilings, linear extensions, descents, and inversions

    CERN Document Server

    Kim, Jang Soo; Panova, Greta; Wilson, David B

    2012-01-01

    Dyck tilings were introduced by Kenyon and Wilson in their study of double-dimer pairings. They are certain kinds of tilings of skew Young diagrams with ribbon tiles shaped like Dyck paths. We give two bijections between "cover-inclusive" Dyck tilings and linear extensions of tree posets. The first bijection maps the statistic (area + tiles)/2 to inversions of the linear extension, and the second bijection maps the "discrepancy" between the upper and lower boundary of the tiling to descents of the linear extension.

  20. Barium halide nanocrystals in fluorozirconate based glass ceramics for scintillation application

    Energy Technology Data Exchange (ETDEWEB)

    Selling, J.

    2007-07-01

    Europium (Eu)-activated barium halide nanocrystals in fluorozirconate based glass ceramics represent a promising class of Xray scintillators. The scintillation in these glass ceramics is mainly caused by the emission of divalent Eu incorporated in hexagonal BaCl{sub 2} nanocrystals which are formed in the glass matrix upon appropriate annealing. Experiments with cerium (Ce)-activated fluorozironate glass ceramics showed that Ce is an interesting alternative. In order to get a better understanding of the scintillation mechanism in Eu- or Ce-activated barium halide nanocrystals, an investigation of the processes in the corresponding bulk material is essential. The objective of this thesis is the investigation of undoped, Eu-, and Ce-doped barium halides by X-ray excited luminescence (XL), pulse height, and scintillation decay spectra. That will help to figure out which of these crystals has the most promising scintillation properties and would be the best nanoparticles for the glass ceramics. Furthermore, alternative dopants like samarium (Sm) and manganese (Mn) were also investigated. Besides the above-mentioned optical investigation electron paramagnetic resonance (EPR) and Moessbauer measurements were carried out in order to complete the picture of Eu-doped barium halides. The EPR data of Eu-doped BaI{sub 2} is anticipated to yield more information about the crystal field and crystal structure that will help to understand the charge carrier process during the scintillation process. The main focus of the Moessbauer investigations was set on the Eu-doped fluorochlorozirconate glass ceramics. The results of this investigation should help to improve the glass ceramics. The Eu{sup 2+}/Eu{sup 3+} ratio in the glass ceramics should be determined and optimize favor of the Eu{sup 2+}. We also want to distinguish between Eu{sup 2+} in the glass matrix and Eu{sup 2+} in the nanocrystals. For a better understanding of Moessbauer spectroscopy on Eu also measurements on Eu in a

  1. Iron-phosphate-based chemically bonded phosphate ceramics for mixed waste stabilization

    International Nuclear Information System (INIS)

    In an effort to develop chemically bonded phosphate ceramics for mixed waste stabilization, a collaborative project to develop iron-phosphate based ceramics has been initiated between Argonne National Laboratory and the V. G. Khlopin Radium Institute in St. Petersburg, Russia. The starter powders are oxides of iron that are generated as inexpensive byproduct materials in the iron and steel industry. They contain iron oxides as a mixture of magnetite (Fe3O4) and haematite (Fe2O3). In this initial phase of this project, both of these compounds were investigated independently. Each was reacted with phosphoric acid solution to form iron phosphate ceramics. In the case of magnetite, the reaction was rapid. Adding ash as the waste component containing hazardous contaminants resulted in a dense and hard ceramic rich in glassy phase. On the other hand, the reaction of phosphoric acid solution with a mixture of haematite and ash waste contaminated with cesium and americium was too slow. Samples had to be molded under pressure. They were cured for 2-3 weeks and then hardened by heating at 350 degrees C for 3 h. The resulting ceramics in both cases were subjected to physical tests for measurement of density, open porosity, compression strength, phase analyses using X-ray diffraction and differential thermal analysis, and leaching tests using toxicity characteristic leaching procedure (TCLP) and ANS 16.1 with 7 days of leaching. Using the preliminary information obtained from these tests, we evaluated these materials for stabilization of Department of Energy's mixed waste streams

  2. Laser Clad ZrO2-Y2O3 Ceramic/Ni-base Alloy Composite Coatings

    OpenAIRE

    Pei, Y.T.; Ouyang, J.H.; Lei, T.C.; Zhou, Y.

    1995-01-01

    A laser cladding technique was used to produce ZrO2-Y2O3 ceramic/Ni-base alloy composite coatings on stainless steel 4Cr13. The microstructure and hardness of the composite coatings are analyzed by XRD, SEM, EPMA, TEM and microhardness testing techniques. A stratification is observed in the laser clad zone. The upper region of the clad is a pure ZrO2 ceramic layer, and the lower region is an excellent transition layer of Ni-base alloy. The ZrO2 ceramic layer exhibits equiaxed grains and colum...

  3. Heart-pulse Biofeedback in Playful Exercise using a Wearable device and Modular Interactive Tiles

    OpenAIRE

    Shimokakimoto, Tomoya; Lund, Henrik Hautop; Suzuki, Kenji

    2014-01-01

    We developed a playful biofeedback system using a wearable device and modular interactive tiles. In this approach we suppose that patients could regulate exercise intensity on their own through biofeedback. We propose biofeedback play system called “bioToys” based on exercise with the modular interactive tiles. The system consists of a wearable device that measures heart-pulse via ear-mounted sensor, and modular interactive tiles which are used for physical rehabilitation exercise through pla...

  4. Monte Carlo Studies of the CALICE AHCAL Tiles Gaps and Non-uniformities

    CERN Document Server

    Sefkow, Felix

    2010-01-01

    The CALICE analog HCAL is a highly granular calorimeter, proposed for the International Linear Collider. It is based on scintillator tiles, read out by silicon photomultipliers (SiPMs). The effects of gaps between the calorimeter tiles, as well as the non-uniform response of the tiles, in view of the impact on the energy resolution, are studied in Monte Carlo events. It is shown that these type of effects do not have a significant influence on the measurement of hadron showers.

  5. Decorative 18th Century Blue-and-White Portuguese Tile Panels: A Type-Case of Environmental Degradation

    Directory of Open Access Journals (Sweden)

    Teresa P. Silva

    2013-01-01

    Full Text Available Decorated glazed ceramic tiles are used as an ornamental art, constituting an important cultural heritage whose preservation is mandatory. Environmental conditions are responsible for the degradation of exposed ancient tile panels originating various pathologies, related to the development of microorganisms. This is the case of a valuable 18th century blue-and-white Portuguese tile panel called “Cura do Cego,” belonging to the collection of the National Tile Museum (MNAz, where green stains are nowadays observable in the glaze. A prospective diagnosis of this green tarnishing was the aim of the present work. Small tile fragments were directly irradiated using nondestructive techniques: X-ray fluorescence spectrometry with a wavelength-dispersive system (WDXRF for chemical characterization of the tile glaze and X-ray powder diffraction (XRD to assess the phase constitution of both the glaze and the ceramic body. A destructive technique (scanning electron microscopy with energy-dispersive system (SEM/EDS was applied to tentatively infer the chemical changes induced in the glaze by the green staining and also to characterize the morphology of the microorganisms associated to this staining. The obtained results are reported and discussed, as a preliminary step for testing an innovative nondestructive decontamination technique applying gamma radiation, particularly suitable for overcoming such tile pathologies.

  6. Feature selection for neural network based defect classification of ceramic components using high frequency ultrasound.

    Science.gov (United States)

    Kesharaju, Manasa; Nagarajah, Romesh

    2015-09-01

    The motivation for this research stems from a need for providing a non-destructive testing method capable of detecting and locating any defects and microstructural variations within armour ceramic components before issuing them to the soldiers who rely on them for their survival. The development of an automated ultrasonic inspection based classification system would make possible the checking of each ceramic component and immediately alert the operator about the presence of defects. Generally, in many classification problems a choice of features or dimensionality reduction is significant and simultaneously very difficult, as a substantial computational effort is required to evaluate possible feature subsets. In this research, a combination of artificial neural networks and genetic algorithms are used to optimize the feature subset used in classification of various defects in reaction-sintered silicon carbide ceramic components. Initially wavelet based feature extraction is implemented from the region of interest. An Artificial Neural Network classifier is employed to evaluate the performance of these features. Genetic Algorithm based feature selection is performed. Principal Component Analysis is a popular technique used for feature selection and is compared with the genetic algorithm based technique in terms of classification accuracy and selection of optimal number of features. The experimental results confirm that features identified by Principal Component Analysis lead to improved performance in terms of classification percentage with 96% than Genetic algorithm with 94%. PMID:26081920

  7. Rhombus Tilings of a Hexagon with Three Fixed Border Tiles

    OpenAIRE

    Eisenkölbl, Theresia

    1997-01-01

    We compute the number of rhombus tilings of a hexagon with sides $a+2,b+2,c+2,a+2,b+2,c+2$ with three fixed tiles touching the border. The particular case $a=b=c$ solves a problem posed by Propp. Our result can also be viewed as the enumeration of plane partitions having $a+2$ rows and $b+2$ columns, with largest entry $\\le c+2$, with a given number of entries $c+2$ in the first row, a given number of entries 0 in the last column and a given bottom-left entry.

  8. Mechanochemically synthesized kalsilite based bioactive glass-ceramic composite for dental vaneering

    Science.gov (United States)

    Kumar, Pattem Hemanth; Singh, Vinay Kumar; Kumar, Pradeep

    2015-08-01

    Kalsilite glass-ceramic composites have been prepared by a mechanochemical synthesis process for dental veneering application. The aim of the present study is to prepare bioactive kalsilite composite material for application in tissue attachment and sealing of the marginal gap between fixed prosthesis and tooth. Mechanochemical synthesis is used for the preparation of microfine kalsilite glass-ceramic. Low temperature frit and bioglass have been prepared using the traditional quench method. Thermal, microstructural and bioactive properties of the composite material have been examined. The feasibility of the kalsilite to be coated on the base commercial opaque as well as the bioactive behavior of the coated specimen has been confirmed. This study indicates that the prepared kalsilite-based composites show similar structural, morphological and bioactive behavior to that of commercial VITA VMK95 Dentin 1M2.

  9. Ceramic thermal wind sensor based on advanced direct chip attaching package

    International Nuclear Information System (INIS)

    An advanced direct chip attaching packaged two-dimensional ceramic thermal wind sensor is studied. The thermal wind sensor chip is fabricated by metal lift-off processes on the ceramic substrate. An advanced direct chip attaching (DCA) packaging is adopted and this new packaged method simplifies the processes of packaging further. Simulations of the advanced DCA packaged sensor based on computational fluid dynamics (CFD) model show the sensor can detect wind speed and direction effectively. The wind tunnel testing results show the advanced DCA packaged sensor can detect the wind direction from 0° to 360° and wind speed from 0 to 20 m/s with the error less than 0.5 m/s. The nonlinear fitting based least square method in Matlab is used to analyze the performance of the sensor. (semiconductor devices)

  10. Multilayer Membranes Based on Ceramic Materials—Sol-gel Synthesis, Characterization and Membrane Performance

    Institute of Scientific and Technical Information of China (English)

    Sun Qianyao; Xu Chunming

    2007-01-01

    In nearly all chemical and petrochemical systems, separation of products generally accounts for more than 50% of the capital cost and the greatest part of the energy consumption. It is generally believed that membrane systems can offer benefits in both reducing the energy consumption of the separation stages and lowering the capital expenditure (CAPEX). Microporous ceramic membranes have the potential to overcome the limitation in polymer membranes operation, which has been the subject of a large amount of research worldwide in the last two decades. And most of the research has aimed at the production of the asymmetric multilayered membrane based on amorphous oxides by sol-gel techniques. The paper is to give an overview of publications on ceramic membranes, including less common materials of titania, zirconia, which can be used for pervaporation in corrosive media. Commercially available microporous membranes based on these membrane materials and the membrane economics are also summarized.

  11. Synthesis of ceramic-based porous gradient structures for applications in energy conversion and related fields

    Science.gov (United States)

    Graule, Thomas; Ozog, Paulina; Durif, Caroline; Wilkens-Heinecke, Judit; Kata, Dariusz

    2016-06-01

    Porous, graded ceramic structures are of high relevance in the field of energy conversion as well as in catalysis, and additionally in filtration technology and in biomedical applications. Among different technologies for the tailored design for such structures we demonstrate here a new environmental friendly UV curing-based concept to prepare laminated structures with pore sizes ranging from a few microns up to 50 microns in diameter and with porosities ranging from 10% up to 75 vol.% porosity.

  12. Polymethyl methacrylate based open-cell porous plastics for high-pressure ceramic casting

    OpenAIRE

    Ergün, Yelda; Dirier, C.; Tanoğlu, Metin

    2004-01-01

    The aim of the present study is to investigate the microstructure-property relation in polymethyl methacrylate (PMMA)-based porous mould materials used for high-pressure casting of ceramic articles. For this purpose, porous plastic materials were produced by the polymerization of water-in-oil emulsions with various compositions of emulsion constituents and particle sizes of the filler PMMA beads. Pore morphology, porosity and water permeability of the materials were measured. The compressive ...

  13. Colloidal processing of Fe-based metalceramic composites with high content of ceramic reinforcement

    OpenAIRE

    Escribano, J.A.; Ferrari, Begoña; Alvaredo Olmos, Paula; Gordo Odériz, Elena; Sánchez-Herencia, A. J.

    2013-01-01

    Major difficulties of processing metal-matrix composites by means of conventional powder metallurgy techniques are the lack of dispersion of the phases within the final microstructure. In this work, processing through colloidal techniques of the Fe-based metal-matrix composites, with a high content of a ceramic reinforcement (Ti(C,N) ), is presented for the first time in the literature. The colloidal approach allows a higher control of the powders packing and a better homogenization of phases...

  14. Environmental durability of ceramics and ceramic composites

    Science.gov (United States)

    Fox, Dennis S.

    1992-01-01

    An account is given of the current understanding of the environmental durability of both monolithic ceramics and ceramic-matrix composites, with a view to the prospective development of methods for the characterization, prediction, and improvement of ceramics' environmental durability. Attention is given to the environmental degradation behaviors of SiC, Si3N4, Al2O3, and glass-ceramic matrix compositions. The focus of corrosion prevention in Si-based ceramics such as SiC and Si3N4 is on the high and low sulfur fuel combustion-product effects encountered in heat engine applications of these ceramics; sintering additives and raw material impurities are noted to play a decisive role in ceramics' high temperature environmental response.

  15. Aluminium based composites strengthened with metallic amorphous phase or ceramic (Al2O3) particles

    International Nuclear Information System (INIS)

    Highlights: • Al-based composites with amorphous Al strengthening phase were obtained. • A better adhesion of metallic amorphous particles than of ceramic phase. • Avoiding crystallization of amorphous phase during a composite pressing process. • Properties similar for 10% metallic amorphous and ceramic strengthening phases. • Better amorphization in case of melt spinning than gas atomization of the Al alloy. - Abstract: Two methods were used to obtain amorphous aluminium alloy powder: gas atomization and melt spinning. The sprayed powder contained only a small amount of the amorphous phase and therefore bulk composites were prepared by hot pressing of aluminium powder with the 10% addition of ball milled melt spun ribbons of the Al84Ni6V5Zr5 alloy (numbers indicate at.%). The properties were compared with those of a composite containing a 10% addition of Al2O3 ceramic particles. Additionally, a composite based on 2618A Al alloy was prepared with the addition of the Al84Ni6V5Zr5 powder from the ribbons used as the strengthening phase. X-ray studies confirmed the presence of the amorphous phase with a small amount of aluminium solid solution in the melt spun ribbons. Differential Scanning Calorimetry (DSC) studies showed the start of the crystallization process of the amorphous ribbons at 437 °C. The composite samples were obtained in the process of uniaxial hot pressing in a vacuum at 380 °C, below the crystallization temperature of the amorphous phase. A uniform distribution of both metallic and ceramic strengthening phases was observed in the composites. The hardness of all the prepared composites was comparable and amounted to approximately 50 HV for those with the Al matrix and 120 HV for the ones with the 2618A alloy matrix. The composites showed a higher yield stress than the hot pressed aluminium or 2618A alloy. Scanning Electron Microscopy (SEM) studies after compression tests revealed that the propagation of cracks in the composites

  16. Design study of an armor tile handling manipulator for the Fusion Experimental Reactor

    International Nuclear Information System (INIS)

    A conceptual design of the Fusion Experimental Reactor (FER), which is a D-T burning reactor following on JT-60 in Japan, has been developed by Japan Atomic Energy Research Institute (JAERI). In FER, a rail-mounted vehicle concept is planned to be adopted for in-vessel maintenance, such as maintenance of divertor plates and armor tiles. Advantages of this concept are the high stiffness of the rail as a base structure for maintenance and the high mobility of the vehicle along the rail. Twin armor tile handling manipulators installed on both sides of the vehicle have been designed. The respective manipulators for armor tile handling have 8 degrees of freedom in order to have access to any place of the first wall and to go through the horizontal port by operating manipulator joints. If the two types of manipulators for divertor plates and armor tiles are installed on the vehicle and the divertor handling manipulator carries a case filled with armor tiles, the replacement time of armor tiles will be reduced. In FER, moreover, maintenance of armor tiles, which is a scheduled maintenance, is planned to be carried out by the autonomous control using position sensors etc. In order to accumulate the data base for the development of the autonomous control of the manipulator in armor tile maintenance, the present paper describes basic mechanical characteristics (stress, deflection and natural frequency) of the armor tile handling manipulator calculated by static stress and dynamic eigenvalue analyses. (orig.)

  17. The isothermal conductivity improvement in zirconia-based ceramics under 24 GHz microwave heating

    International Nuclear Information System (INIS)

    Abstract Under 24-GHz millimetre-wave irradiation heating ionic conductivity of zirconia base ceramics was up to 20 times higher than that of a conventionally-heated sample at the same temperature of 400 °C. The degree of enhancement could be altered by changing the stabilising atom from Y to Yb. Enhancement of ionic conduction was prominent in the setup condition of larger self-heating ratio and larger MMW absorbing materials. The isothermal improvement of ionic conductivity under MMW irradiation would be ascribed to the non-thermal effect. - Highlights: • Under millimetre-wave irradiation heating ionic conductivity of zirconia ceramics was examined. • It was up to 20 times higher than that of a conventionally heating condition. • The activation process was examined in relation to the non-thermal effects. • The operation temperature could be lowered while maintaining the ionic conductivity

  18. The isothermal conductivity improvement in zirconia-based ceramics under 24 GHz microwave heating

    Energy Technology Data Exchange (ETDEWEB)

    Kishimoto, Akira, E-mail: kishim-a@cc.okayama-u.ac.jp; Ayano, Keiko; Teranishi, Takashi; Hayashi, Hidetaka

    2014-01-15

    Abstract Under 24-GHz millimetre-wave irradiation heating ionic conductivity of zirconia base ceramics was up to 20 times higher than that of a conventionally-heated sample at the same temperature of 400 °C. The degree of enhancement could be altered by changing the stabilising atom from Y to Yb. Enhancement of ionic conduction was prominent in the setup condition of larger self-heating ratio and larger MMW absorbing materials. The isothermal improvement of ionic conductivity under MMW irradiation would be ascribed to the non-thermal effect. - Highlights: • Under millimetre-wave irradiation heating ionic conductivity of zirconia ceramics was examined. • It was up to 20 times higher than that of a conventionally heating condition. • The activation process was examined in relation to the non-thermal effects. • The operation temperature could be lowered while maintaining the ionic conductivity.

  19. The influence of {gamma}-irradiation on electrophysical properties of spinel-based oxide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Kovalskiy, A.P.; Shpotyuk, O.I. E-mail: karat@ipm.lviv.ua; Hadzaman, I.V.; Mrooz, O.Ya.; Vakiv, M.M

    2000-05-02

    The influence of {sup 60}Co {gamma}-irradiation with 1.25 MeV average energy and 1 MGy absorbed dose on electrophysical properties of Cu-, Ni-, Co- and Mn-based spinel ceramic materials in the Cu{sub x}Ni{sub 1-x-y}Co{sub 2y}Mn{sub 2-y}O{sub 4} (0,1{<=}x{<=}0,8;0,1{<=}y{<=}0,9-x) system is investigated. The {gamma}-induced increasing of the electrical resistance is observed for the investigated samples of various compositions. It is supposed that these changes are explained by cationic redistribution in the spinel sublattices of the ceramics.

  20. Zirconia-coated carbonyl-iron-particle-based magnetorheological fluid for polishing optical glasses and ceramics

    International Nuclear Information System (INIS)

    We report on magnetorheological finishing (MRF) spotting experiments performed on glasses and ceramics using a zirconia-coated carbonyl-iron (CI)-particle-based magnetorheological (MR) fluid. The zirconia-coated magnetic CI particles were prepared via sol-gel synthesis in kilogram quantities. The coating layer was ∼50-100 nm thick, faceted in surface structure, and well adhered. Coated particles showed long-term stability against aqueous corrosion. ''Free'' nanocrystalline zirconia polishing abrasives were cogenerated in the coating process, resulting in an abrasive-charged powder for MRF. A viable MR fluid was prepared simply by adding water. Spot polishing tests were performed on a variety of optical glasses and ceramics over a period of nearly three weeks with no signs of MR fluid degradation or corrosion. Stable material removal rates and smooth surfaces inside spots were obtained.

  1. Zirconia-coated carbonyl-iron-particle-based magnetorheological fluid for polishing optical glasses and ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Shafrir, Shai N.; Romanofsky, Henry J.; Skarlinski, Michael; Wang, Mimi; Miao, Chunlin; Salzman, Sivan; Chartier, Taylor; Mici, Joni; Lambropoulos, John C.; Shen Rui; Yang Hong; Jacobs, Stephen D.

    2009-12-10

    We report on magnetorheological finishing (MRF) spotting experiments performed on glasses and ceramics using a zirconia-coated carbonyl-iron (CI)-particle-based magnetorheological (MR) fluid. The zirconia-coated magnetic CI particles were prepared via sol-gel synthesis in kilogram quantities. The coating layer was {approx}50-100 nm thick, faceted in surface structure, and well adhered. Coated particles showed long-term stability against aqueous corrosion. ''Free'' nanocrystalline zirconia polishing abrasives were cogenerated in the coating process, resulting in an abrasive-charged powder for MRF. A viable MR fluid was prepared simply by adding water. Spot polishing tests were performed on a variety of optical glasses and ceramics over a period of nearly three weeks with no signs of MR fluid degradation or corrosion. Stable material removal rates and smooth surfaces inside spots were obtained.

  2. Thermoluminescence dating (TL-Dating): an absolute method for archeological dating of ceramic base materials

    International Nuclear Information System (INIS)

    Thermoluminescence dating is one of the known techniques that have been established in many laboratories across the regions. This technique is capable to date the archeological ceramic base materials and provides an absolute measurement with an accuracy of 5%. The study involves the dating of ceramic clay from historical site at Sungai Mas, Kuala Muda, Kedah. Pieces of broken poetry of archeological sample excavated by the Museum Department and Antiquity (JM4) have been dated using the TLD techniques at MINT laboratory. A TLD dosemeter of LiF chips is used for the background and sample dose measurement. The preparation of sample and the calibration techniques for the estimation of palaedose or dose presented in the sample since distant past is established. Results indicate that the samples are in the era of civilization from 200BP to 1600BP. Error factors associated in the measurement procedures are also discussed

  3. The Symbolic Dynamics of Tiling the Integers

    OpenAIRE

    Coven, Ethan M.; Geller, William; Silberger, Sylvia; Thurston, William P.

    1998-01-01

    A finite collection $P$ of finite sets tiles the integers iff the integers can be expressed as a disjoint union of translates of members of $P$. We associate with such a tiling a doubly infinite sequence with entries from $P$. The set of all such sequences is a sofic system, called a tiling system. We show that, up to powers of the shift, every shift of finite type can be realized as a tiling system.

  4. Duality properties between spectra and tilings

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Spectra and tilings play an important role in analysis and geometry respectively.The relations between spectra and tilings have bafied the mathematicians for a long time.Many conjectures,such as the Fuglede conjecture,are placed on the establishment of relations between spectra and tilings,although there are no desired results.In the present paper we derive some characteristic properties of spectra and tilings which highlight certain duality properties between them.

  5. Low Cost Fabrication of Silicon Carbide Based Ceramics and Fiber Reinforced Composites

    Science.gov (United States)

    Singh, M.; Levine, S. R.

    1995-01-01

    A low cost processing technique called reaction forming for the fabrication of near-net and complex shaped components of silicon carbide based ceramics and composites is presented. This process consists of the production of a microporous carbon preform and subsequent infiltration with liquid silicon or silicon-refractory metal alloys. The microporous preforms are made by the pyrolysis of a polymerized resin mixture with very good control of pore volume and pore size thereby yielding materials with tailorable microstructure and composition. Mechanical properties (elastic modulus, flexural strength, and fracture toughness) of reaction-formed silicon carbide ceramics are presented. This processing approach is suitable for various kinds of reinforcements such as whiskers, particulates, fibers (tows, weaves, and filaments), and 3-D architectures. This approach has also been used to fabricate continuous silicon carbide fiber reinforced ceramic composites (CFCC's) with silicon carbide based matrices. Strong and tough composites with tailorable matrix microstructure and composition have been obtained. Microstructure and thermomechanical properties of a silicon carbide (SCS-6) fiber reinforced reaction-formed silicon carbide matrix composites are discussed.

  6. Triangle Tiling IV: A non-isosceles tile with a 120 degree angle

    OpenAIRE

    Beeson, Michael

    2012-01-01

    An N-tiling of triangle ABC by triangle T is a way of writing ABC as a union of N trianglescongruent to T, overlapping only at their boundaries. The triangle T is the "tile". The tile may or may not be similar to ABC. We wish to understand possible tilings by completely characterizing the triples (ABC, T, N) such that ABC can be N-tiled by T. In particular, this understanding should enable us to specify for which N there exists a tile T and a triangle ABC that is N-tiled by T; or given N, det...

  7. Development of a nondestructive method for underglaze painted tiles--demonstrated by the analysis of Persian objects from the nineteenth century.

    Science.gov (United States)

    Reiche, Ina; Röhrs, Stefan; Salomon, Joseph; Kanngiesser, Birgit; Höhn, Yvonne; Malzer, Wolfgang; Voigt, Friederike

    2009-02-01

    The paper presents an analytical method developed for the nondestructive study of nineteenth-century Persian polychrome underglaze painted tiles. As an example, 9 tiles from French and German museum collections were investigated. Before this work was undertaken little was known about the materials used in pottery at that time, although the broad range of colors and shades, together with their brilliant glazes, made these objects stand out when compared with Iranian ceramics of the preceding periods and suggested the use of new pigments, colorants, and glaze compositions. These materials are thought to be related to provenance and as such appropriate criteria for art-historical attribution. The analytical method is based on the combination of different nondestructive spectroscopic techniques using microfocused beams such as proton-induced X-ray emission/proton-induced gamma-ray emission, X-ray fluorescence, 3D X-ray absorption near edge structure, and confocal Raman spectroscopy and also visible spectroscopy. It was established to address the specific difficulties these objects and the technique of underglaze painting raise. The exact definition of the colors observed on the tiles using the Natural Color System helped to attribute them to different colorants. It was possible to establish the presence of Cr- and U-based colorants as new materials in nineteenth-century Persian tilemaking. The difference in glaze composition (Pb, Sn, Na, and K contents) as well as the use of B and Sn were identified as a potential marker for different workshops. PMID:19030848

  8. Mechanical properties of microwave sintered Si3N4-based ceramics

    Directory of Open Access Journals (Sweden)

    Getman O.I.

    2002-01-01

    Full Text Available The mechanical properties and microstructure formation processes in Si3N4+3% AI2O3+5% Y2O3(Yb2O3 ceramic compacts sintered under microwave heating (MWH and under traditional heating (TH were investigated. The initial ceramic materials were powder blends of silicon nitride with oxides. The mean powder particle sizes were 0.5-1.0 mim. The content of alfa-phase in the Si3N4 powder was more than 95 %. The samples were sintered at 1800BC in nitrogen at normal pressure, the heating rate in all experiments was 60BC/min. The Vickers hardness (HV, fracture toughness (K1C and bending strength (on were determined. The microstructures of fracture surfaces of samples were studied by SEM. Quantitative microstructure analysis was carried out. It was shown that the values of HV and Kic of ceramic samples sintered under MWH at 1800BC rose steadily with the sintering time. This caused an increase in density, which reached maximum as fast as after 30 min of the MWH sintering; the mass loss at that time amounted to 3-4 %. The porosity of sintered samples with an addition of yttria was less than 1 %, that of ytterbia was greater, 2.4 %. For similar values of relative density, the hardness and fracture toughness of ceramic samples produced under MWH were higher as compared with those of samples sintered under TH. The microstructure of samples had the form of elongated grains in a matrix of polyhedral grains of the beta-Si3N4 phase. Measurements showed the mean size of grains in samples produced by MWH to be greater that in samples produced by TH. A larger number of elongated grains were formed. It was concluded that for sintering under MWH of Si3N4-based ceramics the growth of elongated beta-Si3N4 grains and formation of a "reinforced" microstructure were promoted and thereby improved the mechanical properties of such ceramics.

  9. Asymptotic structure in substitution tiling spaces

    CERN Document Server

    Barge, Marcy

    2011-01-01

    Every sufficiently regular space of tilings of $\\R^d$ has at least one pair of distinct tilings that are asymptotic under translation in all the directions of some open $(d-1)$-dimensional hemisphere. If the tiling space comes from a substitution, there is a way of defining a location on such tilings at which asymptoticity `starts'. This leads to the definition of the {\\em branch locus} of the tiling space: this is a subspace of the tiling space, of dimension at most $d-1$, that summarizes the `asymptotic in at least a half-space' behavior in the tiling space. We prove that if a $d$-dimensional self-similar substitution tiling space has a pair of distinct tilings that are asymptotic in a set of directions that contains a closed $(d-1)$-hemisphere in its interior, then the branch locus is a topological invariant of the tiling space. If the tiling space is a 2-dimensional self-similar Pisot substitution tiling space, the branch locus has a description as an inverse limit of an expanding Markov map on a 1-dimens...

  10. Life cycle assessment and product category rules for the construction sector. The floor and wall tiles sector case study; Analisis de ciclo de vida y reglas de categoria de producto en la construccion. El caso de las baldosas ceramicas

    Energy Technology Data Exchange (ETDEWEB)

    Benveniste, G.; Gazulla, C.; Fullana, P.; Celades, I.; Ros, T.; Zaera, V.; Godes, B.

    2011-07-01

    This paper illustrates the Life Cycle Analysis (LCA) activities performed during the preparation of the Spanish Product Category Rules (PCR) relative to the construction sector. Specifically, the study presents the results obtained from the life cycle analysis of the floor and wall tile sector, which served as the basis for the drafting of the PCR required for the definition of Environmental Product Declarations (EPD). More than 50 Spanish companies in the ceramic tile sector participated in the study, providing inventory data on the manufacture of their products. Additionally, bibliographic information and the GaBi 4 software database by PE International were used to complete background and generic data, such as those related to energy and transportation processes. EPDs are voluntary declarations based on LCA studies that permit the disclosure and dissemination of environmental information quantified over the life cycle of a product. The definition of PCRs for ceramic tiles was performed in accordance to the UNE EN ISO 14025 and ISO 21930 standards and they have been submitted to industries and professional association public consultations. PCRs have been developed in the context of the DAPc program (promoted by the Catalan Government and CAATEEB) and represents the first eco labelling activity for building products in Spain. (Author) 18 refs.

  11. Numerical investigation of the spatial scale and time dependency of tile drainage contribution to stream flow

    Science.gov (United States)

    Thomas, Nicholas W.; Arenas, Antonio A.; Schilling, Keith E.; Weber, Larry J.

    2016-07-01

    Tile drainage systems are pervasive in the Central U.S., significantly altering the hydrologic system. The purpose of this study was to assess the effects of tile drainage systems on streamflow. A physically based coupled hydrologic model was applied to a 45 km2 agricultural Iowa watershed. Tile drainage was incorporated though an equivalent porous medium approach, calibrated though numerical experimentation. Experimental results indicated that a significant increase in hydraulic conductivity of the equivalent medium layer was needed to achieve agreement in total outflow with an explicit numerical representation of a tiled system. Watershed scale analysis derived the tile drainage contribution to stream flow (QT/Q) from a numerical tracer driven analysis of instream surface water. During precipitation events tile drainage represented 30% of stream flow, whereas during intervals between precipitations events, 61% of stream flow originated from the tile system. A division of event and non-event periods produced strong correlations between QT/Q and drainage area, positive for events, and negative for non-events. The addition of precipitation into the system acted to saturate near surface soils, increase lateral soil water movement, and dilute the relatively stable instream tile flow. Increased intensity precipitation translated the QT/Q relationship downward in a consistent manner. In non-event durations, flat upland areas contributed large contributions of tile flow, diluted by larger groundwater (non-tile) contribution to stream flow in the downstream steeper portion of the watershed. Study results provide new insights on the spatiotemporal response of tile drainage to precipitation and contributions of tile drainage to streamflow at a watershed scale, with results having important implications for nitrate transport.

  12. Fast Distribution Method for Large Data Set of Spatial Data Based on Tiles Pyramid Model%基于瓦片金字塔模型的海量空间数据快速分发方法

    Institute of Scientific and Technical Information of China (English)

    殷君茹; 侯瑞霞; 唐小明; 罗鹏

    2015-01-01

    针对分布式并行环境下海量空间数据的快速显示和浏览问题,提出一种基于分层、分专题的海量空间数据金字塔模型及基于数据库存储方案的瓦片数据快速分发方法。对比分析了瓦片数据在文件式管理和数据库管理两种模式下的存储机制和响应流程,并以时间跨度59年的沙尘暴观测数据为例,验证了该方法不仅能有效地组织管理海量空间数据,实现高效数据互操作,而且在多用户并发访问时,能快速响应客户端请求。%In view of the problem of showing and browsing large data set of spatial data in the distributed parallel environment quickly,not only one kind of massive spatial pyramid model based on a hierarchical and special topic mechanism,but high access performance tile map service based on database storage scheme under the tiles pyramid model technology were proposed.The mechanism of tile data file management and database management under the storage performance and response process were comparatively analyzed.Moreover,sand and dust storm observation data for 59 years was taken as an example to validate that this method can not only effectively organize and manage massive spatial data to achieve efficient data interoperability,but also quickly respond to client requests in the multi-user concurrent access.

  13. Research on Micro-Flow Self-Sensing Actuators Based on Piezoelectric Ceramic Stack

    Institute of Scientific and Technical Information of China (English)

    Yan-Bo Wei; Li-Ping Shi; Xi-Wen Wei; Jie Huang

    2014-01-01

    The paper is concerned with the micro-flow self-sensing actuators, the work of which is based on the secondary piezoelectric effect. The piezoelectric ceramic stack can yield micro-displacement due to its first inverse piezoelectric effect. Therefore, we apply this micro-displacement to cell micro-flow injection. Moreover, due to the charge of the secondary direct piezoelectric effect, the piezoelectric ceramic stack is able to detect the force and displacement in the injection by itself. The experiments of first inverse piezoelectric effect and secondary direct piezoelectric effect are conducted. The experiment results show that, subjected to 0-60 V input, the piezoelectric ceramic stack can generate 13�45 μm displacement, and control accuracy can achieve 2 nm. It can completely meet the needs of cell micro-flow injection. Also, the experiments demonstrate that the micro-displacement due to the first inverse piezoelectric effect can be well self-sensed by the electric charge due to the secondary direct piezoelectric effect.

  14. Additive Manufacturing of Reactive In Situ Zr Based Ultra-High Temperature Ceramic Composites

    Science.gov (United States)

    Sahasrabudhe, Himanshu; Bandyopadhyay, Amit

    2016-03-01

    Reactive in situ multi-material additive manufacturing of ZrB2-based ultra-high-temperature ceramics in a Zr metal matrix was demonstrated using LENS™. Sound metallurgical bonding was achieved between the Zr metal and Zr-BN composites with Ti6Al4V substrate. Though the feedstock Zr power had α phase, LENS™ processing of the Zr powder and Zr-BN premix powder mixture led to the formation of some β phase of Zr. Microstructure of the Zr-BN composite showed primary grains of zirconium diboride phase in zirconium metal matrix. The presence of ZrB2 ceramic phase was confirmed by X-ray diffraction (XRD) analysis. Hardness of pure Zr was measured as 280 ± 12 HV and, by increasing the BN content in the feedstock, the hardness was found to increase. In Zr-5%BN composite, the hardness was 421 ± 10 HV and the same for Zr-10%BN composite was 562 ± 10 HV. It is envisioned that such multi-materials additive manufacturing will enable products in the future that cannot be manufactured using traditional approaches particularly in the areas of high-temperature metal-ceramic composites with compositional and functional gradation.

  15. Effect of Zirconia Thickness on the Tensile Stress of Zirconia Based All-Ceramic Restorations

    Directory of Open Access Journals (Sweden)

    Masood Shiezadeh

    2015-09-01

    Full Text Available Introduction: The purpose of the presented study was to evaluate the effect of zirconia thickness on the tensile stress of zirconia based all-ceramic restorations. Methods: Twenty zirconia disks with 10mm diameter were prepared in two groups using CAD/CAM system. The thickness of zirconia was 0.5mm in first group and 0.3mm in second group. After sintering, 0.4mm glass ceramic porcelain was applied to each disk. Then, sintering and glazing of porcelain carried out. Instron testing machine with 1mm/min crosshead speed used to evaluate the failure load of the samples. Biaxial Flexural strength standard formula employed to calculate tensile stress of specimens. Statistical analysis performed using SPSS software. Results: Although data analysis showed more maximum tensile stress in 1st group, no significant differences were found between two groups. Conclusion: Zirconia with 0.5mm and 0.3mm thicknesses cause similar tensile stress in all-ceramic restorations and thickness of these laminates could be reduced to 0.7mm.

  16. Developing ceramic based technology for the immobilisation of waste on the Sellafield site - 16049

    International Nuclear Information System (INIS)

    National Nuclear Laboratory, in collaboration with the Australian Nuclear Science and Technology Organisation, is developing hot isostatic press (HIP) based ceramic technology for the immobilisation of a diverse range of wastes arising from nuclear fuel processing activities on the Sellafield site. Wasteform compositions have been identified and validated for the immobilisation of these plutonium containing wastes and residues in glass-ceramic and ceramic forms. A full scale inactive facility has been constructed at NNL's Workington Laboratory to support the demonstration of the technology. Validation of the inactive wasteform development using plutonium has been carried out at ANSTO's Lucas Heights facility. A feasibility study has been conducted to evaluate the construction and operation of a plutonium active pilot facility which would demonstrate the immobilisation of actual residues in the NNL Central Lab. This could form the basis of a facility to treat the plutonium wastes and residues in their entirety. The technology is being explored for the immobilisation of additional wastes arising on the Sellafield site taking advantage of the investment already made in skills and facilities. (authors)

  17. Damage formation, fatigue behavior and strength properties of ZrO2-based ceramics

    Science.gov (United States)

    Kozulin, A. A.; Narikovich, A. S.; Kulkov, S. N.; Leitsin, V. N.; Kulkov, S. S.

    2016-08-01

    It is suggested that a non-destructive testing technique using a three-dimensional X-ray tomography be applied to detecting internal structural defects and monitoring damage formation in a ceramic composite structure subjected to a bending load. Three-point bending tests are used to investigate the fatigue behavior and mechanical and physical properties of medical-grade ZrO2-based ceramics. The bending strength and flexural modulus are derived under static conditions at a loading rate of 2 mm/min. The fatigue strength and fatigue limit under dynamic loading are investigated at a frequency of 10 Hz in three stress ranges: 0.91-0.98, 0.8-0.83, and 0.73-0.77 MPa of the static bending strength. The average values of the bending strength and flexural modulus of sintered specimens are 43 MPa and 22 GPa, respectively. The mechanical properties of the ceramics are found to be similar to those of bone tissues. The testing results lead us to conclude that the fatigue limit obtained from 105 stress cycles is in the range 33-34 MPa, i.e. it accounts for about 75% of the static bending strength for the test material.

  18. Metal-ceramic composite development based on its modelling results

    Science.gov (United States)

    Dvilis, E. S.; Khasanov, O. L.; Khasanov, A. O.; Petyukevich, M. S.

    2016-02-01

    The modeling (and its experimental verification) of packing and deformation of the composites consisted of aluminum-magnesium alloy AMg6, B4C powder and W nano-powder has been performed. The powder compositions were determined using discrete element modeling of the composite particles packing based on the particle size distribution functions of real powders. The models of maximum mixture packing densities have been rendered.

  19. Translational tilings by a polytope, with multiplicity

    OpenAIRE

    Gravin, Nick; Robins, Sinai; Shiryaev, Dmitry

    2011-01-01

    We study the problem of covering R^d by overlapping translates of a convex body P, such that almost every point of R^d is covered exactly k times. Such a covering of Euclidean space by translations is called a k-tiling. The investigation of tilings (i.e. 1-tilings in this context) by translations began with the work of Fedorov and Minkowski. Here we extend the investigations of Minkowski to k-tilings by proving that if a convex body k-tiles R^d by translations, then it is centrally symmetric,...

  20. Tiling spaces are Cantor set fiber bundles

    OpenAIRE

    Sadun, Lorenzo; Williams, R F

    2001-01-01

    We prove that fairly general spaces of tilings of R^d are fiber bundles over the torus T^d, with totally disconnected fiber. This was conjectured (in a weaker form) in [W3], and proved in certain cases. In fact, we show that each such space is homeomorphic to the d-fold suspension of a Z^d subshift (or equivalently, a tiling space whose tiles are marked unit d-cubes). The only restrictions on our tiling spaces are that 1) the tiles are assumed to be polygons (polyhedra if d>2) that meet full-...

  1. Algebraic properties of basic isohedral marked tilings

    Science.gov (United States)

    Greco, Gabriele H.

    2006-05-01

    In 1977 Grünbaum and Shephard described all possible 93 types of isohedral marked tilings of the plane; 46 of them are called basic, since their induced tile group is trivial. The aim of this paper is to give an algebraic description of all basic tilings. A purely algebraic characterization of the adjacency symmetries of tiles of the 46 basic tilings is presented. Moreover, 46 related abstract definitions of two-dimensional crystallographic groups supplement and extend those of the well-known book Generators and Relations for Discrete Groups by Coxeter and Moser.

  2. Tungsten band edge absorber/emitter based on a monolayer of ceramic microspheres.

    Science.gov (United States)

    Dyachenko, P N; do Rosário, J J; Leib, E W; Petrov, A Yu; Störmer, M; Weller, H; Vossmeyer, T; Schneider, G A; Eich, M

    2015-09-21

    We report on a band edge absorber/emitter design for high-temperature applications based on an unstructured tungsten substrate and a monolayer of ceramic microspheres. The absorber was fabricated as a monolayer of ZrO(2) microparticles on a tungsten layer with a HfO(2) nanocoating. The band edge of the absorption is based on critically coupled microsphere resonances. It can be tuned from visible to near-infrared range by varying the diameter of the microparticles. The absorption properties were found to be stable up to 1000°C. PMID:26406752

  3. Plasma-Sprayed Refractory Oxide Coatings on Silicon-Base Ceramics

    Science.gov (United States)

    Tewari, Surendra

    1997-01-01

    Silicon-base ceramics are promising candidate materials for high temperature structural applications such as heat exchangers, gas turbines and advanced internal combustion engines. Composites based on these materials are leading candidates for combustor materials for HSCT gas turbine engines. These materials possess a combination of excellent physical and mechanical properties at high temperatures, for example, high strength, high toughness, high thermal shock resistance, high thermal conductivity, light weight and excellent oxidation resistance. However, environmental durability can be significantly reduced in certain conditions such as when molten salts, H2 or water vapor are present. The oxidation resistance of silicon-base materials is provided by SiO2 protective layer. Molten salt reacts with SiO2 and forms a mixture of SiO2 and liquid silicate at temperatures above 800C. Oxygen diffuses more easily through the chemically altered layer, resulting in a catastrophic degradation of the substrate. SiC and Si3N4 are not stable in pure H2 and decompose to silicon and gaseous species such as CH4, SiH, SiH4, N2, and NH3. Water vapor is known to slightly increase the oxidation rate of SiC and Si3N4. Refractory oxides such as alumina, yttria-stabilized zirconia, yttria and mullite (3Al2O3.2SiO2) possess excellent environmental durability in harsh conditions mentioned above. Therefore, refractory oxide coatings on silicon-base ceramics can substantially improve the environmental durability of these materials by acting as a chemical reaction barrier. These oxide coatings can also serve as a thermal barrier. The purpose of this research program has been to develop refractory oxide chemical/thermal barrier coatings on silicon-base ceramics to provide extended temperature range and lifetime to these materials in harsh environments.

  4. 基于混合瓦片的海量DEM/DOM数据高效存储管理方法--以应急救灾数据库为例%Efficient Storage Management of Massive DEM/DOM Data Based on Mixed Tile Range:A Case Study of Emergency Relief Database

    Institute of Scientific and Technical Information of China (English)

    吴晨; 朱庆; 张叶廷; 许伟平

    2014-01-01

    The traditional method of managing DEM/DOM is based on partitioning terrain tiles using the same tile range, which results in inefficient storage of the large number of small DEM files. This paper builds a mixed DEM/DOM tile pyramid on the mathematical basis of traditional terrain pyramid. The new pyramid considers the data characteristics that DEM tile size is much smaller than the DOM tile size. By dividing DEM/DOM tile with different tile ranges, packaging space-related small files into a bigger one, the new pyramid effectively balances the DEM/DOM tile sizes and reduces the DEM files number, which greatly improves the storage efficiency. This paper offers a new method which designs a new tile ID structure to implicitly store the mapping relationship of non-equilibrium DEM/DOM tiles. Finally, the validity and feasibility of this method are proved through the experiment in the platform of distributed database MongoDB.%针对传统DEM/DOM数据存储管理采用同一瓦片剖分导致大量DEM小文件入库效率极低的问题,在传统地形金字塔的数学基础上,建立DEM/DOM混合瓦片的金字塔模型。该模型考虑相同空间范围内DEM瓦片文件远小于DOM瓦片文件大小的数据特点,通过为DEM和DOM划分不同的瓦片范围,平衡瓦片文件大小;将空间相关的DEM瓦片打包,以减少文件数量,提高入库效率;设计了瓦片ID的编码方式,隐式存储非均衡瓦片范围的DEM瓦片和DOM瓦片的映射关系,支持无缝调度和浏览。以分布式数据库MongoDB为平台进行实验,验证了本文方法的可行性和有效性。

  5. Translational tilings by a polytope, with multiplicity

    CERN Document Server

    Gravin, Nick; Shiryaev, Dmitry

    2011-01-01

    We study the problem of covering R^d by overlapping translates of a convex body P, such that almost every point of R^d is covered exactly k times. Such a covering of Euclidean space by translations is called a k-tiling. The investigation of tilings (i.e. 1-tilings in this context) by translations began with the work of Fedorov and Minkowski. Here we extend the investigations of Minkowski to k-tilings by proving that if a convex body k-tiles R^d by translations, then it is centrally symmetric, and its facets are also centrally symmetric. These are the analogues of Minkowski's conditions for 1-tiling polytopes. Conversely, in the case that P is a rational polytope, we also prove that if P is centrally symmetric and has centrally symmetric facets, then P must k-tile R^d for some positive integer k.

  6. Investigation of registration algorithms for the automatic tile processing system

    Science.gov (United States)

    Tamir, Dan E.

    1995-01-01

    The Robotic Tile Inspection System (RTPS), under development in NASA-KSC, is expected to automate the processes of post-flight re-water-proofing and the process of inspection of the Shuttle heat absorbing tiles. An important task of the robot vision sub-system is to register the 'real-world' coordinates with the coordinates of the robot model of the Shuttle tiles. The model coordinates relate to a tile data-base and pre-flight tile-images. In the registration process, current (post-flight) images are aligned with pre-flight images to detect the rotation and translation displacement required for the coordinate systems rectification. The research activities performed this summer included study and evaluation of the registration algorithm that is currently implemented by the RTPS, as well as, investigation of the utility of other registration algorithms. It has been found that the current algorithm is not robust enough. This algorithm has a success rate of less than 80% and is, therefore, not suitable for complying with the requirements of the RTPS. Modifications to the current algorithm has been developed and tested. These modifications can improve the performance of the registration algorithm in a significant way. However, this improvement is not sufficient to satisfy system requirements. A new algorithm for registration has been developed and tested. This algorithm presented very high degree of robustness with success rate of 96%.

  7. Nucleation and crystallization of tailing-based glass-ceramics by microwave heating

    Institute of Scientific and Technical Information of China (English)

    Bao-wei Li; Hong-xia Li; Xue-feng Zhang; Xiao-lin Jia; Zhi-chao Sun

    2015-01-01

    The effect of microwave radiation on the nucleation and crystallization of tailing-based glass-ceramics was investigated using a 2.45 GHz multimode microwave cavity. Tailing-based glass samples were prepared from Shandong gold tailings and Guyang iron tailings utilizing a conventional glass melting technique. For comparison, the tailing-based glass samples were crystallized using two different heat-treatment meth-ods:conventional heating and hybrid microwave heating. The nucleation and crystallization temperatures were determined by performing a dif-ferential thermal analysis of the quenched tailing-based glass. The prepared glass-ceramic samples were further characterized by Fourier trans-form infrared spectroscopy, X-ray diffraction, Raman spectroscopy, thermal expansion coefficient measurements, and scanning electron micros-copy. The results demonstrated that hybrid microwave heating could be successfully used to crystallize the tailing-based glass, reduce the proc-essing time, and decrease the crystallization temperature. Furthermore, the results indicated that the nucleation and crystallization mechanism of the hybrid microwave heating process slightly differs from that of the conventional heating process.

  8. Nucleation and crystallization of tailing-based glass-ceramics by microwave heating

    Science.gov (United States)

    Li, Bao-wei; Li, Hong-xia; Zhang, Xue-feng; Jia, Xiao-lin; Sun, Zhi-chao

    2015-12-01

    The effect of microwave radiation on the nucleation and crystallization of tailing-based glass-ceramics was investigated using a 2.45 GHz multimode microwave cavity. Tailing-based glass samples were prepared from Shandong gold tailings and Guyang iron tailings utilizing a conventional glass melting technique. For comparison, the tailing-based glass samples were crystallized using two different heat-treatment methods: conventional heating and hybrid microwave heating. The nucleation and crystallization temperatures were determined by performing a differential thermal analysis of the quenched tailing-based glass. The prepared glass-ceramic samples were further characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, thermal expansion coefficient measurements, and scanning electron microscopy. The results demonstrated that hybrid microwave heating could be successfully used to crystallize the tailing-based glass, reduce the processing time, and decrease the crystallization temperature. Furthermore, the results indicated that the nucleation and crystallization mechanism of the hybrid microwave heating process slightly differs from that of the conventional heating process.

  9. Polymer-Ceramic Nanocomposites Based on New Concepts for Embedded Capacitor

    Science.gov (United States)

    Takahashi, Akio; Kakimoto, Masa-Aki; Tsurumi, Taka-Aki; Hao, Jianjun; Li, Li; Kikuchi, Ryohei; Miwa, Takao; Ohno, Toshiyuki; Yamada, Shinji; Takezawa, Yoshitaka

    A rapid growth of mixed-signal integrated circuits is driving the needs of multifunction and miniaturization of the component in electronics applications. Polymer-ceramic composites have been of great interest as embedded capacitor materials because they enabled companies to combine the processability of polymers with the high dielectric constant of ceramics. Polymer-ceramic nanocomposites based on new concepts were developed for embedded capacitor applications. The dielectric constant was above 80 at 1 MHz and the specific capacitance was successfully achieved 8 nF/cm2. By use of this nanocomposites, multilayer printed wiring boards with embedded passive components were fabricated for prototypes. The following technologies are reported in this paper. Firstly, based on the investigation of barium titanium oxide (BaTiO3) crystallites, various particles with the sizes from 17 nm to 100 nm were prepared by the 2-step thermal decomposition method from barium titanyl oxalate (BaTiO(C2O4)2·4H2O). It was clarified that BaTiO3 particles with a size of around 70 nm exhibited a maximum dielectric constant of over 15,000 by FEM analysis from the measured dielectric constants of BaTiO3 suspensions. Secondary, the BaTiO3 surface modification based on a new concept was applied to improve the affinity between BaTiO3 particles and polymer matrix. Thirdly, the blend polymer of an aromatic polyamide (PA) and an aromatic bismaleimide (BMI) was employed as the matrix from a view-point of both the processabilty during fabricating the substrates with embedded passive components and the thermal stability during assembling LSI chips. Finally, these technologies were combined and optimized for embedded capacitor materials.

  10. Ceramics reinforced metal base composite coatings produced by CO II laser cladding

    Science.gov (United States)

    Yang, Xichen; Wang, Yu; Yang, Nan

    2008-03-01

    Due to the excellent performance in high strength, anti-temperature and anti-wear, ceramics reinforced metal base composite material was used in some important fields of aircraft, aerospace, automobile and defense. The traditional bulk metal base composite materials are the expensive cost, which is limited in its industrial application. Development of laser coating of ceramics reinforced metal base composite is very interesting in economy. This paper is focused on three laser cladding ceramics coatings of SiC particle /Al matrix , Al IIO 3 powder/ Al matrix and WC + Co/mild steel matrix. Powder particle sizes are of 10-60μm. Chemical contents of aluminum matrix are of 3.8-4.0% Cu, 1.2-1.8% Mg, 0.3-0.99% Mn and balance Al. 5KW CO II laser, 5 axes CNC table, JKF-6 type powder feeder and co-axis feeder nozzle are used in laser cladding. Microstructure and performance of laser composite coatings have been respectively examined with OM,SEM and X-ray diffraction. Its results are as follows : Microstructures of 3C-,6H- and 5H- SiC particles + Al + Al 4SiC 4 + Si in SiC/Al composite, hexagonal α-Al IIO 3 + cubic γ-Al IIO 3 + f.c.c Al in Al IIO 3 powder/ Al composite and original WC particles + separated WC particles + eutectic WC + γ-Co solid solution + W IIC particles in WC + Co/steel coatings are respectively recognized. New microstructures of 5H-SiC in SiC/Al composite, cubic γ-Al IIO 3 in Al IIO 3 composite and W IIC in WC + Co/ steel composite by laser cladding have been respectively observed.

  11. Calibration of the Tile Hadronic Calorimeter of ATLAS at LHC

    CERN Document Server

    Boumediene, D

    2015-01-01

    The TileCal is the hadronic calorimeter covering the most central region of the ATLAS experiment at LHC. It is a sampling calorimeter with iron plates as absorber and plastic scintillating tiles as the active material. The scintillation light produced by the passage of charged particles is transmitted by wavelength shifting fibers to about 10000 photomultiplier tubes (PMTs). Integrated to the calorimeter, there is a composite device that allows to monitor and/or equalize the signals at various stages of their formation. This device is based on signal generation from different sources: radioactive, Laser, charge injection and minimum bias events produced in proton-proton collisions. Recent performances of these systems as well TileCal calibration stability are presented.

  12. Reuse of sugarcane bagasse ash (SCBA) to produce ceramic materials.

    Science.gov (United States)

    Souza, A E; Teixeira, S R; Santos, G T A; Costa, F B; Longo, E

    2011-10-01

    Sugarcane bagasse ash (SCBA) is a residue resulting from the burning of bagasse in boilers in the sugarcane/alcohol industry. SCBA has a very high silica concentration and contains aluminum, iron, alkalis and alkaline earth oxides in smaller amounts. In this work, the properties of sintered ceramic bodies were evaluated based on the concentration of SCBA, which replaced non-plastic material. The ash was mixed (up to 60 wt%) with a clayed raw material that is used to produce roof tiles. Prismatic probes were pressed and sintered at different temperatures (up to 1200 °C). Technological tests of ceramic probes showed that the addition of ash has little influence on the ceramic properties up to 1000 °C. X-ray diffraction and thermal analysis data showed that, above this temperature the ash participates in the sintering process and in the formation of new important phases. The results reported show that the reuse of SCBA in the ceramic industry is feasible. PMID:21733619

  13. High-temperature soldering of carborundum-based ceramics with TZM molybdenum alloy

    International Nuclear Information System (INIS)

    In the paper, properties of a modern composite material designed SiC30 silicon carbide based with a fraction of graphite and free silicon are presented. Due to such properties like high hardness, thermal shock, wear and chemical resistance, this material is applied for heavy-duty machine parts and high-temperature regime parts. However, the specific structure of this silicide ceramics makes additional difficulties in the process of bonding with metals. Subsequent phases of the experiment and its analysis are presented. As a result, satisfactory bonds of the SiC-C-Si ceramics with the TZM molybdenum-based high-temperature alloy were obtained. When choosing the copper based, high temperature solder with active components Cr, Zr and Ti, the wettability test played an immense role. To obtain a soldered joint, the wedge test was of most importance. This test permitted assessment of the existing physicochemical phenomena, choice of the gap width and its transfer to the parallel joint. This resulted in obtaining a soldered joint od advantageous structure with no cracks. Metallographic evaluation of the joints was based on optical and electron microscopy and on microhardness measurements. (author)

  14. Study of the sintering variables in the Si3 N4 based ceramic microstructures

    International Nuclear Information System (INIS)

    This paper shows the influence of some sintering parameters in the microstructure of Si3 N4 based ceramics with additives to form liquid phase. Samples with Al2 O3 and AIN additions were obtained to form Si A/ON with 5, 10, 15, 20 Al eq% and 5 wt% rare earth concentrates. The results show that the increase in the final sintering time, temperature and heating rate lead to grain growth. However, increasing the Al concentration, the grain size in average decreases and grains become more spherical. (author)

  15. FEAMAC/CARES Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix Composites

    Science.gov (United States)

    Nemeth, Noel; Bednarcyk, Brett; Pineda, Evan; Arnold, Steven; Mital, Subodh; Murthy, Pappu; Bhatt, Ramakrishna

    2016-01-01

    Reported here is a coupling of two NASA developed codes: CARES (Ceramics Analysis and Reliability Evaluation of Structures) with the MAC/GMC (Micromechanics Analysis Code/ Generalized Method of Cells) composite material analysis code. The resulting code is called FEAMAC/CARES and is constructed as an Abaqus finite element analysis UMAT (user defined material). Here we describe the FEAMAC/CARES code and an example problem (taken from the open literature) of a laminated CMC in off-axis loading is shown. FEAMAC/CARES performs stochastic-strength-based damage simulation response of a CMC under multiaxial loading using elastic stiffness reduction of the failed elements.

  16. High-strength zirconium diboride-based ceramic composites consolidated by low-temperature hot pressing

    OpenAIRE

    Shuqi Guo and Yutaka Kagawa

    2012-01-01

    Two compositions of ZrB2-based ceramic composites containing Si3N4, Al2O3 and Y2O3 have been hot-pressed at different temperatures between 1673 and 1773 K for 60 min in vacuum. The densification behavior of the composites was examined during the sintering process. The microstructures of the composites were characterized by scanning electron microscopy, and the crystalline phases were identified by x-ray diffraction. The effects of Al2O3 and Y2O3 additives on the densification behavior and fle...

  17. Transverse Laplacians for Substitution Tilings

    CERN Document Server

    Julien, Antoine

    2009-01-01

    Pearson and Bellissard recently built a spectral triple - the data of Riemanian noncommutative geometry - for ultrametric Cantor sets. They derived a family of Laplace-Beltrami like operators on those sets. Motivated by the applications to specific examples, we revisit their work for the transversals of tiling spaces, which are particular self-similar Cantor sets. We use Bratteli diagrams to encode the self-similarity, and Cuntz-Krieger algebras to implement it. We show that the abscissa of convergence of the zeta-function of the spectral triple gives indications on the exponent of complexity of the tiling. We determine completely the spectrum of the Laplace-Beltrami operators, give an explicit method of calculation for their eigenvalues, compute their Weyl asymptotics, and a Seeley equivalent for their heat kernels.

  18. Glass-ceramic frits for porcelain stoneware bodies: effects on sintering, phase composition and technological properties

    OpenAIRE

    Zanelli, Chiara; Baldi, Giovanni; Dondi, Michele; Ercolani, Giampaolo; Guarini, Guia; Raimondo, Maria Rosa

    2008-01-01

    In the present work, the effects of glass-ceramic frits (10wt%) added to a porcelain stoneware body in replacement of non-plastic raw materials, were evaluated simulating the tile-making process. Each glass-ceramic frit plays its own peculiar effect on the compositional properties and only some precursors behave as real glass ceramic materials. The positive influence of glass-ceramic precursors in promoting the sintering stands out when temperature onset densification and sintering rate are c...

  19. Geometrical tile design for complex neighborhoods

    Directory of Open Access Journals (Sweden)

    Eugen Czeizler

    2009-11-01

    Full Text Available Recent research has showed that tile systems are one of the most suitable theoretical frameworks for the spatial study and modeling of self-assembly processes, such as the formation of DNA and protein oligomeric structures. A Wang tile is a unit square, with glues on its edges, attaching to other tiles and forming larger and larger structures. Although quite intuitive, the idea of glues placed on the edges of a tile is not always natural for simulating the interactions occurring in some real systems. For example, when considering protein self-assembly, the shape of a protein is the main determinant of its functions and its interactions with other proteins. Our goal is to use geometric tiles, i.e. square tiles with geometrical protrusions on their edges, for simulating tiled paths (zippers with complex neighborhoods, by ribbons of geometric tiles with simple, local neighborhoods. This paper is a step toward solving the general case of an arbitrary neighborhood, by proposing geometric tile designs that solve the case of a tall von Neumann neighborhood, the case of the f-shaped neighborhood, and the case of a 3 x 5 filled rectangular neighborhood. The techniques can be combined and generalized to solve the problem in the case of any neighborhood, centered at the tile of reference, and included in a 3 x (2k+1 rectangle.

  20. Geometrical tile design for complex neighborhoods.

    Science.gov (United States)

    Czeizler, Eugen; Kari, Lila

    2009-01-01

    Recent research has showed that tile systems are one of the most suitable theoretical frameworks for the spatial study and modeling of self-assembly processes, such as the formation of DNA and protein oligomeric structures. A Wang tile is a unit square, with glues on its edges, attaching to other tiles and forming larger and larger structures. Although quite intuitive, the idea of glues placed on the edges of a tile is not always natural for simulating the interactions occurring in some real systems. For example, when considering protein self-assembly, the shape of a protein is the main determinant of its functions and its interactions with other proteins. Our goal is to use geometric tiles, i.e., square tiles with geometrical protrusions on their edges, for simulating tiled paths (zippers) with complex neighborhoods, by ribbons of geometric tiles with simple, local neighborhoods. This paper is a step toward solving the general case of an arbitrary neighborhood, by proposing geometric tile designs that solve the case of a "tall" von Neumann neighborhood, the case of the f-shaped neighborhood, and the case of a 3 x 5 "filled" rectangular neighborhood. The techniques can be combined and generalized to solve the problem in the case of any neighborhood, centered at the tile of reference, and included in a 3 x (2k + 1) rectangle. PMID:19956398

  1. Fracture toughness determination of ceramic and resin-based dental composites.

    Science.gov (United States)

    Kvam, K

    1992-01-01

    A new method has been developed for Klc determinations of brittle materials with precracks introduced by indentations. A reference glass, five ceramic materials, and one resin-based composite were tested. Knoop hardness indentations were made with a load of 49 N in a line from edge to edge vertical to the long axis on one surface of four-point flexure bars, to make a continuous crack under the indentations. Five specimens of each material were fractured in a four-point bend test with the line of indentations placed in the zone of constant and maximum tensile stress. Separate unfractured specimens were ground and polished to expose and measure the preformed continuous crack. The mean of six crack-depth measurements was used together with the fracture load and the dimensions of the bend specimens to calculate the fracture toughness, Klc of each material. The determined Klc value (x +/- SD) for the reference glass was 0.81 +/- .24 MPa m1/2 and corresponds to previous studies. The resin-based composite material, Silux Plus, had a value of 1.04 +/- 0.14 MPa m1/2. The Klc values (MPa m1/2) were 0.94 +/- 0.31 for Dicor, 1.41 +/- 0.18 for Cerestore, 1.50 +/- 0.29 for NBK-1000, 1.60 +/- 0.17 for Vitadur-N and 2.14 +/- 0.14 for Hi-Ceram. Hi-Ceram had significantly higher Klc values than the other materials. The new method seemed to be of value in determining the fracture toughness of non-metallic dental materials. PMID:1550892

  2. Integration Science and Technology of Silicon-Based Ceramics and Composites:Technical Challenges and Opportunities

    Science.gov (United States)

    Singh, M.

    2013-01-01

    Ceramic integration technologies enable hierarchical design and manufacturing of intricate ceramic and composite parts starting with geometrically simpler units that are subsequently joined to themselves and/or to metals to create components with progressively higher levels of complexity and functionality. However, for the development of robust and reliable integrated systems with optimum performance for high temperature applications, detailed understanding of various thermochemical and thermomechanical factors is critical. Different technical approaches are required for the integration of ceramic to ceramic and ceramic to metal systems. Active metal brazing, in particular, is a simple and cost-effective method to integrate ceramic to metallic components. Active braze alloys usually contain a reactive filler metal (e.g., Ti, Cr, V, Hf etc) that promotes wettability and spreading by inducing chemical reactions with the ceramics and composites. In this presentation, various examples of brazing of silicon nitride to themselves and to metallic systems are presented. Other examples of joining of ceramic composites (C/SiC and SiC/SiC) using ceramic interlayers and the resulting microstructures are also presented. Thermomechanical characterization of joints is presented for both types of systems. In addition, various challenges and opportunities in design, fabrication, and testing of integrated similar (ceramic-ceramic) and dissimilar (ceramic-metal) material systems will be discussed. Potential opportunities and need for the development of innovative design philosophies, approaches, and integrated system testing under simulated application conditions will also be presented.

  3. Cell response of calcium phosphate based ceramics, a bone substitute material

    Directory of Open Access Journals (Sweden)

    Juliana Marchi

    2013-01-01

    Full Text Available The aim of this study was to characterize calcium phosphate ceramics with different Ca/P ratios and evaluate cell response of these materials for use as a bone substitute. Bioceramics consisting of mixtures of hydroxyapatite (HAp and β-tricalcium phosphate (β-TCP powders in different proportions were pressed and sintered. The physical and chemical properties of these bioceramics were then characterized. Characterization of the biological properties of these materials was based on analysis of cell response using cultured fibroblasts. The number of cells attached to the samples was counted from SEM images of samples exposed to cell culture solution for different periods. These data were compared by analysis of variance (ANOVA complemented by the Tukey's test. The TCP sample had higher surface roughness and lower density. The adherence and growth of FMM1 cells on samples from all groups was studied. Even though the different calcium based ceramics exhibited properties which made them suitable as bone substitutes, those with higher levels of β-TCP revealed improved cell growth on their surfaces. These observations indicated two-phase calcium phosphate based materials with a β-TCP surface layer to be a promising bone substitute.

  4. Fracture resistance of endodontically treated teeth restored with ceramic inlays and different base materials.

    Science.gov (United States)

    Saridag, Serkan; Sari, Tugrul; Ozyesil, Atilla Gokhan; Ari Aydinbelge, Hale

    2015-01-01

    This study evaluated the fracture resistance of endodontically treated teeth restored with different base materials and mesioocclusal-distal (MOD) ceramic inlays. Fifty mandibular molars were assigned into five groups (n=10 per group). Group1 (control) comprised intact molar teeth without any treatment. Teeth in other groups were subjected to root canal treatment and restored with MOD ceramic inlays on different base materials. In Group 2, base material was zinc phosphate cement; Group 3's was glass ionomer cement; Group 4's was composite resin, and Group 5's was composite resin reinforced with fiber. Finally, a continuous occlusal load was applied until fracture occurred. Mean fracture resistance of Group 1 (3,027 N) was significantly higher than the other groups (890, 1,070, 1,670, 1,226 N respectively). Fracture resistance of Group 4 was statistically comparable with Group 5 and significantly higher than Groups 2 and 3 (pinlay restorations could affect the fracture resistance of endodontically treated teeth. PMID:25740162

  5. Geometric realization for substitution tilings

    CERN Document Server

    Barge, Marcy

    2011-01-01

    Given an n-dimensional substitution whose associated linear expansion is unimodular and hyperbolic, we use elements of the one-dimensional integer \\v{C}ech cohomology of the associated tiling space to construct a finite-to-one semi-conjugacy, called geometric realization, between the substitution induced dynamics and an invariant set of a hyperbolic toral automorphism. If the linear expansion satisfies a Pisot family condition and the rank of the module of generalized return vectors equals the generalized degree of the linear expansion, the image of geometric realization is the entire torus and coincides with the map onto the maximal equicontinuous factor of the translation action on the tiling space. We are led to formulate a higher-dimensional generalization of the Pisot Substitution Conjecture: If the linear expansion satisfies the Pisot family condition and the rank of the one-dimensional cohomology of the tiling space equals the generalized degree of the linear expansion, then the translation action on t...

  6. Desempenho de telhas de escória de alto forno e fibras vegetais em protótipos de galpões Performance of tiles composed of blast furnace slag and vegetable fiber in prototype barns

    Directory of Open Access Journals (Sweden)

    Maristela N. da Conceição

    2008-10-01

    Full Text Available Busca-se, em todo o mundo, a substituição do cimento amianto por alternativas seguras para o ambiente e para a saúde do trabalhador, além de econômicas, razão por que o uso de fibras vegetais como aglomerado em países tropicais onde estes resíduos são abundantes, tem-se mostrado bastante viável. No presente experimento foram comparadas telhas de cimento amianto pintadas com tinta reflexiva, telhas cerâmicas e telhas compostas de uma matriz à base de cimento Portland CPII 32Z (ABNT NBR-5735, escória de alto-forno (EAF e sílica ativa, reforçadas com fibras de polpa celulósica de sisal (Agave sisalana. Utilizaram-se protótipos de galpões avícolas nos quais o calor produzido pelas aves foi simulado por lâmpadas incandescentes. Para caracterização do ambiente térmico lançou-se mão dos índices de conforto: ITU (índice de temperatura e umidade, ITGU (índice de temperatura de globo e umidade, CTR (carga térmica radiante e entalpia (H em que os resultados demonstraram que as telhas compostas apresentaram comportamento térmico semelhante ao das telhas cerâmicas, podendo ser utilizadas em substituição às telhas de cimento amianto.The substitution of cement asbestos by safer and equally economical alternatives has being searched for throughout the world. The usage of vegetal staple fiber as agglomerate in tropical countries where these residues are abundant has shown it self to be viable. In this study, roofing tiles fabricated with cement base Portland CPII 32Z (ABNT NBR-5735, blast furnace slag (EAF, active silica reinforced with cellulose pulp staple fibers of sisal (Agave sisalana were compared with cement asbestos roofing tiles with white paint and ceramic roofing tiles. Prototypes of poultry facilities were used and lamps simulated the heat produced by the birds. Indices ITU, ITGU, CTR and entalpy (H were employed for the characterization of the thermal atmospheric comfort and the results showed that the alternative

  7. Microstructural studies on some silicate and phosphate based glass-ceramics

    International Nuclear Information System (INIS)

    Recent developments have made it possible to make a new class of ceramic materials called glass-ceramics with tailored expansion coefficients and improved thermo-mechanical and corrosion resistance properties. Since these are formed by controlled crystallization in which crystallites are embedded in the glassy matrix, it is possible to make nano glass-ceramics having pronounced effect of particle size on various properties such as transparency, bioactivity, etc. In this talk, some of the recent results on micro-structural properties of a few glass-ceramic-to-metal sealants and bio-glass-ceramics are discussed

  8. Tungstate-based glass-ceramics for the immobilization of radio cesium

    Energy Technology Data Exchange (ETDEWEB)

    Drabarek, Elizabeth; McLeod, Terry I.; Hanna, John V.; Griffith, Christopher S. [Australian Nuclear Science and Technology Organisation, Institute of Materials Engineering, New Illawarra Road, PMB 1, Menai, Lucas Heights, NSW 2234 (Australia); Luca, Vittorio [Australian Nuclear Science and Technology Organisation, Institute of Materials Engineering, New Illawarra Road, PMB 1, Menai, Lucas Heights, NSW 2234 (Australia)], E-mail: vlu@ansto.gov.au

    2009-02-15

    The preparation of tungstate-containing glass-ceramic composites (GCC) for the potential immobilization of radio cesium has been considered. The GCC materials were prepared by blending two oxide precursor compositions in various proportions. These included a preformed Cs-containing hexagonal tungsten bronze (HTB) phase (Cs{sub 0.3}Ti{sub 0.2}W{sub 0.8}O{sub 3}, P6{sub 3}/mcm) and a blend of silica and other oxides. The use of the HTB phase was motivated on the assumption that a HTB-based adsorbent could be used to remove cesium directly from aqueous high level liquid waste feeds. In the absence of the HTB, glass-ceramics were relatively easily prepared from the Cs-containing glass-forming oxide blend. On melting the mixture a relative complex GCC phase assemblage formed. The principal components of this phase assemblage were determined using X-ray powder diffraction, {sup 133}Cs MAS-NMR, and cross-sectional SEM and included glass, various zeolites, scheelite (CaWO{sub 4}) and a range of other oxide phases and Cs-containing aluminosilicate. Importantly, under no circumstance was cesium partitioned into the glass phase irrespective of whether or not the composition included the preformed Cs-containing HTB compound. For compositions containing the HTB, cesium was partitioned into one of four major phases including zeolite; Cs-silica-tungstate bronze, pollucite (CsAlSi{sub 2}O{sub 6}), and an aluminosilicate with an Al/Si ratio close to one. The leach resistance of all materials was evaluated and related to the cesium distribution within the GCC phase assemblages. In general, the GCCs prepared from the HTB had superior durability compared with materials not containing tungsten. Indeed the compositions in many cases had leach resistances comparable to the best ceramics or glass materials.

  9. Tungstate-based glass-ceramics for the immobilization of radio cesium

    International Nuclear Information System (INIS)

    The preparation of tungstate-containing glass-ceramic composites (GCC) for the potential immobilization of radio cesium has been considered. The GCC materials were prepared by blending two oxide precursor compositions in various proportions. These included a preformed Cs-containing hexagonal tungsten bronze (HTB) phase (Cs0.3Ti0.2W0.8O3, P63/mcm) and a blend of silica and other oxides. The use of the HTB phase was motivated on the assumption that a HTB-based adsorbent could be used to remove cesium directly from aqueous high level liquid waste feeds. In the absence of the HTB, glass-ceramics were relatively easily prepared from the Cs-containing glass-forming oxide blend. On melting the mixture a relative complex GCC phase assemblage formed. The principal components of this phase assemblage were determined using X-ray powder diffraction, 133Cs MAS-NMR, and cross-sectional SEM and included glass, various zeolites, scheelite (CaWO4) and a range of other oxide phases and Cs-containing aluminosilicate. Importantly, under no circumstance was cesium partitioned into the glass phase irrespective of whether or not the composition included the preformed Cs-containing HTB compound. For compositions containing the HTB, cesium was partitioned into one of four major phases including zeolite; Cs-silica-tungstate bronze, pollucite (CsAlSi2O6), and an aluminosilicate with an Al/Si ratio close to one. The leach resistance of all materials was evaluated and related to the cesium distribution within the GCC phase assemblages. In general, the GCCs prepared from the HTB had superior durability compared with materials not containing tungsten. Indeed the compositions in many cases had leach resistances comparable to the best ceramics or glass materials

  10. Heart-pulse Biofeedback in Playful Exercise using a Wearable device and Modular Interactive Tiles

    DEFF Research Database (Denmark)

    Shimokakimoto, Tomoya; Lund, Henrik Hautop; Suzuki, Kenji

    2014-01-01

    interactive tiles. The system consists of a wearable device that measures heart-pulse via ear-mounted sensor, and modular interactive tiles which are used for physical rehabilitation exercise through playing a game. The wearable devise enables detection of heart pulse in real-time and therefore provides heart...... beat rate during playful activities, even if the heart pulse wave have motion artifacts. The tiles are designed to build flexible structures and to provide immediate feedback based on the users’ physical interaction with the tiles. We combine the two systems to provide users with heart pulse...... biofeedback in playful exercise. We show that using the developed system it is possible for the users to regulate the exercise intensity on their own with biofeedback, and also possible to analyze exercise activity using number of steps on the tiles and heart beat rate....

  11. Spectral structure of digit sets of self-similar tiles on ${Bbb R}^1$

    CERN Document Server

    Lai, Chun-Kit; Rao, Hui

    2011-01-01

    We study the structure of the digit sets ${\\mathcal D}$ for the integral self-similar tiles $T(b,{\\mathcal{D}})$ (we call such ${\\mathcal D}$ a {\\it tile digit set} with respect to $b$). So far the only available classes of such tile digit sets are the complete residue sets and the product-forms. Our investigation here is based on the spectrum of the mask polynomial $P_{\\mathcal D}$, i.e., the zeros of $P_{\\mathcal D}$ on the unit circle. By using the Fourier criteria of self-similar tiles of Kenyon and Protasov, as well as the algebraic techniques of cyclotomic polynomial, we characterize the tile digit sets through some product of cyclotomic polynomials (kernel polynomials), which is a generalization of the product-form to higher order.

  12. A Multi-core multithreaded parallel computation technique for DNA sequence comparison using tiling mechanism

    Directory of Open Access Journals (Sweden)

    Harshita G.Patil

    2012-01-01

    Full Text Available This Project shows the issues involved in implementing adynamic programming algorithm for biological sequencecomparison on a general purpose parallel computingplatform based on fine –grain event –driven multithreadedprogram execution model. Fine –grain multithreadingpermits efficient parallelism in this application both bytaking advantage of asynchronous point-to–pointsynchronizations and communication with low overheadsand by effectively tolerating latency through theoverlapping of computation and communication. For thistiling technique can be implemented. Tiling is an importanttechnique for extraction of parallelism. Informally, tilingconsists of partitioning the iteration space into severalchunks of computation called tiles (blocks such thatsequential traversal of the tiles covers the entire iterationspace. The idea behind tiling is to increase the granularityof computation and decrease the amount of communicationincurred between processors. This makes tiling moresuitable for distributed memory architectures wherecommunication startup costs are very high and hencefrequent communication is undesirable. Our work todevelop sequence-comparison mechanism and softwaresupports the identification of sequences of DNA

  13. Analysis of Toxicity of Ceramic Nanoparticles and Functional Nanocomposites Based on Vulcanized Natural Rubber

    Directory of Open Access Journals (Sweden)

    Bellucci Felipe Silva

    2015-01-01

    Full Text Available Nanocomposites are multiphase materials of which, at least one of the phases, has a dimension smaller than 100 nm. These materials have attracted technological and scientific interest due to their multifunctional characteristics and potential, which allow them to combine unique properties which are not found in traditional commercial materials, such as natural rubber alone. The objective of this work is to analyse the toxicity of nanoparticles and nanocomposites when applied to mammal cells in order to obtain bioactive agents, as well as to evaluate the potential to be applied in biological systems. Ferroelectric ceramic nanoparticles of KSr2Nb5O15 (KSN and paramagnetic ceramic nanoparticles Ni0.5Zn0.5Fe2O4 (NZF were prepared and utilized to produce functional and multifunctional nanocomposites based on vulcanized natural rubber (NR/KSN and NR/NZF with different nanoparticle concentrations. For both kinds of nanoparticles and both classes of nanocomposites, independently of the nanoparticle concentration, it is not possible to observe any reduction of the cellular viability until the incubation time is finished. In this way, these results point to the possibility of using these nanoparticles and nanocomposites, from the toxicity point of view, as bioactivity agents in biological systems based on mammalian cells.

  14. Synthesis and Properties of a Bridged Siloxane for Protection of Architectural Glazed Tiles of the Qing Dynasty in the Forbidden City

    OpenAIRE

    HAN Xiang-Na, HUANG Xiao, LUO Hong-Jie

    2014-01-01

    The architectural glazed tiles of the Qing dynasty in the Forbidden City are the most important glazed ceramic of China. But some serious deterioration such as color change, dirty, craze crack, efflorescence and glazed layer spallation are observed in some tiles. In this paper, a bridged siloxane (BSQ) protective material focusing on glazed layer spallation issue was designed and synthesized starting with isophorone diisocyanate (IPDI) and 3-aminopropyltriethoxysilane. Important properties in...

  15. MLD Relations of Pisot Substitution Tilings

    CERN Document Server

    Gähler, Franz

    2010-01-01

    We consider 1-dimensional, unimodular Pisot substitution tilings with three intervals, and discuss conditions under which pairs of such tilings are locally isomorhphic (LI), or mutually locally derivable (MDL). For this purpose, we regard the substitutions as homomorphisms of the underlying free group with three generators. Then, if two substitutions are conjugated by an inner automorphism of the free group, the two tilings are LI, and a conjugating outer automorphism between two substitutions can often be used to prove that the two tilings are MLD. We present several examples illustrating the different phenomena that can occur in this context. In particular, we show how two substitution tilings can be MLD even if their substitution matrices are not equal, but only conjugate in $GL(n,\\mathbb{Z})$. We also illustrate how the (in our case fractal) windows of MLD tilings can be reconstructed from each other, and discuss how the conjugating group automorphism affects the substitution generating the window boundar...

  16. Naturally Occurring Radionuclides in Pottery, Ceramic and Glasswares Produced in Bangladesh

    International Nuclear Information System (INIS)

    The concentrations of naturally occurring radionuclides were measured using gamma spectrometry in the finished products of pottery, glass, ceramic and tiles. Ceramic and pottery utensils, tiles, basin and glassware contained naturally occurring radionuclides. Pottery is produced from local clay materials, but ceramic, tiles, basin and glassware's are made from both local and imported raw materials. Radium and thorium radionuclides are concentrated during the making of pottery from the clay materials due to calcination. Radionuclides concentrated more in the highly calcined pottery products than the low calcined products. Glassware products contained very low quantities of radionuclides comparing with the ceramic and pottery products. Study on radioactivity in the pottery, ceramic and glassware products is important in the assessment of possible radiological hazards to human health. The knowledge is essential for the development of standards and guidelines for the use and management of these materials. (author)

  17. Comparative evaluation of effect of laser on shear bond strength of ceramic bonded with two base metal alloys: An in-vitro study

    OpenAIRE

    K. Deepak; S C Ahila; Muthukumar, B.; M Vasanthkumar

    2013-01-01

    The most common clinical failure in metal ceramic restoration is at the ceramo-metal interface. For the clinical longevity, metal-ceramic prostheses must have satisfactory bond strength between metal and ceramic. Aim and Objective: The aim of this study is to evaluate the effect of Laser etching on shear bond strength between base metal alloys and ceramic. Materials and Methods: A total of 60 specimens were made (Base 5 mm diameter and 1 mm thickness, step with 4 mm diameter and 4 mm ...

  18. Microfabrication of a Novel Ceramic Pressure Sensor with High Sensitivity Based on Low-Temperature Co-Fired Ceramic (LTCC) Technology

    OpenAIRE

    Chen Li; Qiulin Tan; Wendong Zhang; Chenyang Xue; Yunzhi Li; Jijun Xiong

    2014-01-01

    In this paper, a novel capacitance pressure sensor based on Low-Temperature Co-Fired Ceramic (LTCC) technology is proposed for pressure measurement. This approach differs from the traditional fabrication process for a LTCC pressure sensor because a 4J33 iron-nickel-cobalt alloy is applied to avoid the collapse of the cavity and to improve the performance of the sensor. Unlike the traditional LTCC sensor, the sensitive membrane of the proposed sensor is very flat, and the deformation of the se...

  19. Geometrical Tile Design for Complex Neighborhoods

    OpenAIRE

    Czeizler, Eugen; Kari, Lila

    2009-01-01

    Recent research has showed that tile systems are one of the most suitable theoretical frameworks for the spatial study and modeling of self-assembly processes, such as the formation of DNA and protein oligomeric structures. A Wang tile is a unit square, with glues on its edges, attaching to other tiles and forming larger and larger structures. Although quite intuitive, the idea of glues placed on the edges of a tile is not always natural for simulating the interactions occurring in some real ...

  20. Geometrical tile design for complex neighborhoods

    OpenAIRE

    Eugen Czeizler

    2009-01-01

    Recent research has showed that tile systems are one of the most suitable theoretical frameworks for the spatial study and modeling of self-assembly processes, such as the formation of DNA and protein oligomeric structures. A Wang tile is a unit square, with glues on its edges, attaching to other tiles and forming larger and larger structures. Although quite intuitive, the idea of glues placed on the edges of a tile is not always natural for simulating the interactions occurring in some rea...

  1. Multilayer Impregnated Fibrous Thermal Insulation Tiles

    Science.gov (United States)

    Tran, Huy K.; Rasky, Daniel J.; Szalai, Christine e.; Hsu, Ming-ta; Carroll, Joseph A.

    2007-01-01

    The term "secondary polymer layered impregnated tile" ("SPLIT") denotes a type of ablative composite-material thermal- insulation tiles having engineered, spatially non-uniform compositions. The term "secondary" refers to the fact that each tile contains at least two polymer layers wherein endothermic reactions absorb considerable amounts of heat, thereby helping to prevent overheating of an underlying structure. These tiles were invented to afford lighter-weight alternatives to the reusable thermal-insulation materials heretofore variously used or considered for use in protecting the space shuttles and other spacecraft from intense atmospheric-entry heating.

  2. C∗-algebras of Penrose hyperbolic tilings

    Science.gov (United States)

    Oyono-Oyono, Hervé; Petite, Samuel

    2011-02-01

    Penrose hyperbolic tilings are tilings of the hyperbolic plane which admit, up to affine transformations a finite number of prototiles. In this paper, we give a complete description of the C∗-algebras and of the K-theory for such tilings. Since the continuous hull of these tilings have no transversally invariant measure, these C∗-algebras are traceless. Nevertheless, harmonic currents give rise to 3-cyclic cocycles and we discuss in this setting a higher-order version of the gap-labeling.

  3. Solid-liquid state pressure bonding of Si3N4 ceramics with aluminum based alloys and its mechanism

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Solid-liquid state pressure bonding of Si3N4 ceramics with aluminum based alloys, which contain a small amount of intermetallic compounds Al3Ti or Al3Zr, was investigated. With this new method, the heat resistant properties of the bonding zone metal are improved, and the joints' strengths at high temperature is increased. The joints' shear strength at room temperature and at 600  ℃ reach 126~133  MPa and 32~34  MPa, respectively, with suitable bonding pressure. The reaction between aluminum and Si3N4 ceramics, which produces Al-Si-N-O type compounds is the dominant interfacial reaction, while the reactions between the second active element Ti or Zr in the aluminum based alloys and Si3N4 ceramics also occur to some extend.

  4. The effect of ceramic thickness and number of firings on the color of a zirconium oxide based all ceramic system fabricated using CAD/CAM technology

    OpenAIRE

    Bachhav, Vinay Chila; Aras, Meena Ajay

    2011-01-01

    PURPOSE Ceramics have a long history in fixed prosthodontics for achieving optimal esthetics and various materials have been used to improve ceramic core strength. However, there is a lack of information on how color is affected by fabrication procedure. The purpose of this study was to evaluate the effects of various dentin ceramic thicknesses and repeated firings on the color of zirconium oxide all-ceramic system (Lava™) fabricated using CAD/CAM technology. MATERIALS AND METHODS Thirty disc...

  5. Broadband mid-infrared wavelength conversion laser based on Cr2+ doped ceramic materials

    Science.gov (United States)

    Shang, Yaping; Yin, Ke; Li, Xiao; Wang, Peng; Xu, Xiaojun

    2015-10-01

    Broadband mid-infrared lasers are desirable for pretty important applications in fields of environmental protection, medical treatment, military applications, scientific, and other domains. Recently, super-continuum laser sources have achieved striking development. However, limited by the substrate materials, the output power scaling of the broadband mid-infrared fiber laser sources could not be increased drastically, especially for the long wavelength region. In this paper, we reported an experimental study about the broadband mid-infrared lasers based on Cr2+ doped II-VI ceramic materials, by using of a super-continuum laser source developed by our groups operating at 1550~2130nm with 200mW output power. The result suggested that the near-infrared spectral component of the super-continuum source was deeply absorbed by transition metal doped zinc chalcogenides ceramic materials, meanwhile the mid-infrared part, however, had been enhanced significantly by this new "power amplifier." Actually single-pass amplification efficiency was very limited. The best way to solve this problem was multi-pass amplification systems. We had shown an initial proof of this assumption by a double-pass experiments, the result was consistent with expected effect. Above all, the spectrum shaping from short wavelength to long wavelength was obtained. The innovative discovery had laid a solid foundation for high power, high efficiency, broadly tunable mid-infrared solid state lasers.

  6. Chemical compatibility between lithium-based oxide ceramics and stainless steels

    International Nuclear Information System (INIS)

    The compatibility behavior of Li-based oxide ceramics with stainless steels has been investigated between 500 and 8000C for annealing times of 125 and 500 h. The materials examined include Li2O, LiAlO2, Li2SiO3, Li4SiO4 and Li2ZrO3 on one side and one martensitic-ferritic and two austenitic steels on the other side. The breeder materials contained various amounts of H2O or NiO as initial contamination. Below 0.2 mol% H2O per 1 mol Li2O no chemical interaction took place between the oxide ceramics and the cladding materials. At higher H2O contents, Li2O caused the strongest cladding attack followed by Li4SiO4, Li2SiO3, LiAlO2 and Li2ZrO3. The extent of reaction of the stainless steels investigated is comparable up to 7000C. The presence or formation of LiOH is not necessary for the chemical interactions, however, a sufficiently high oxygen potential is needed in the system to oxidize the cladding. The resulting cladding oxides then can interact with the breeder materials. (orig.)

  7. Ceramic carbon electrode-based anodes for use in the copper-chlorine thermochemical cycle

    International Nuclear Information System (INIS)

    Sol-gel chemistry is becoming more popular for the synthesis of electrode materials. For example, the sol-gel reaction can be performed in the presence of a carbon black to form a ceramic carbon electrode (CCE). The resultant CCE structure contains electronically conductive carbon particle pathways that are bound together via the ceramic binder, which can also promote ion transport. Furthermore, the CCE structure has a high active surface area and is chemical and thermally robust. We have investigated CCE materials prepared using 3-aminopropyl trimethoxysilane. Electrochemical experiments (cyclic voltammetry, electrochemical impedance spectroscopy) were performed to characterize their suitability as anode electrode materials for use in the electrochemical step of the Cu-Cl thermochemical cycle. Our initial results have shown that CCE-based electrodes vastly outperform a bare carbon electrode, and thus are highly promising and cost-effective electrode material. Subsequent experiments involved the manipulation of the relative ratio of organosilane carbon precursors to gauge its impact on electrode properties and performance. An overview of the materials characterization and electrochemical measurements will be presented. (author)

  8. Novel Processing of Unique Ceramic-Based Nuclear Materials and Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hui Zhang; Raman P. Singh

    2008-11-30

    Advances in nuclear reactor technology and the use of gas-cooled fast reactors require the development of new materials that can operate at the higher temperatures expected in these systems. These include refractory alloys base on Nb, Zr, Ta, Mo, W, and Re; ceramics and composites such as those based on silicon carbide (SiCf-SiC); carbon-carbon composites; and advanced coatings. Besides the ability to handle higher expected temperatures, effective heat transfer between reactor componets is necessary for improved efficiency. Improving thermal conductivity of the materials used in nuclear fuels and other temperature critical components can lower the center-line fuel temperature and thereby enhance durability and reduce the risk of premature failure.

  9. Novel Processing of Unique Ceramic-Based Nuclear Materials and Fuels

    International Nuclear Information System (INIS)

    Advances in nuclear reactor technology and the use of gas-cooled fast reactors require the development of new materials that can operate at the higher temperatures expected in these systems. These include refractory alloys base on Nb, Zr, Ta, Mo, W, and Re; ceramics and composites such as those based on silicon carbide (SiCf-SiC); carbon-carbon composites; and advanced coatings. Besides the ability to handle higher expected temperatures, effective heat transfer between reactor components is necessary for improved efficiency. Improving thermal conductivity of the materials used in nuclear fuels and other temperature critical components can lower the center-line fuel temperature and thereby enhance durability and reduce the risk of premature failure.

  10. Statistical design for recycling kaolin processing waste in the manufacturing of mullite-based ceramics

    Directory of Open Access Journals (Sweden)

    Romualdo Rodrigues Menezes

    2009-06-01

    Full Text Available Mineral extraction and processing industries have been cited as sources of environmental contamination and pollution. However, waste recycling represents an alternative recovery option, which is interesting from an environmental and economic standpoint. In this work, recycling of kaolin processing waste in the manufacture of mullite-based ceramics was investigated based on the statistical design of mixture experiments methodology. Ten formulations using kaolin processing waste, alumina and ball clay were used in the experiment design. Test specimens were fired and characterized to determine their water absorption and modulus of rupture. Regression models were calculated, relating the properties with the composition. The significance and validity of the models were confirmed through statistical analysis and verification experiments. The regression models were used to analyze the influence of waste content on the properties of the fired bodies. The results indicated that the statistical design of mixture experiments methodology can be successfully used to optimize formulations containing large amount of wastes.

  11. Development of ceramic support the base of cordierite for one-side welding; Desenvolvimento de suporte ceramico a base de cordierita para soldagem unilateral

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, L.L.P. de; Vieira, C.M.F.; Paranhos, R.P.R.; Tatagiba, L.C.S. [Universidade Estadual do Norte Fluminense Darcy Ribeiro (LAMAV/UENF), Campos dos Goytacazes, RJ (Brazil). Lab. de Materiais Avancados

    2009-07-01

    This work has as objective develops ceramic backing for the execution of one side welds in steel. The backing consists the mixture of refractory mineral (Cordierite), adhesive (sodium silicate) and water. Test coupons produced by uniaxial pressing and burned to 1100 deg C they were submitted to physical and mechanical tests for determination the water absorption and flexion strength, respectively. The microstructure of ceramics produced was evaluated by diffraction of X-Ray, scanning electron microscopy and optical microscopy. After the production of the ceramic backing, welding tests were accomplished by the process MIG-MAG to evaluate the format of the weld bead. Based on the results obtained, during and after the welding accomplished with the employment of the ceramic backing, has shown that it is technically feasible for one-side welding. (author)

  12. Optical thermometry based on luminescence behavior of Dy3+-doped transparent LaF3 glass ceramics

    International Nuclear Information System (INIS)

    Dy3+-doped transparent LaF3 glass ceramics were fabricated, and its structures of resulting glass ceramics are studied by the X-ray diffraction and transmission electron microscopy. Optical temperature sensing of the resulting glass ceramics in the temperature range from 298 to 523 K is studied based on the down-conversion luminescence of Dy3+ ion. By using fluorescence intensity ratio method, the 4I15/2 and 4F9/2 of Dy3+ ions are verified as thermally coupled levels. A minimum SR = 1.16 x 10-4 K-1 is obtained at T = 294 K. By doping Eu3+ ion, the overall emission color of Eu3+-Dy3+ co-doped transparent glass ceramics can be tuned from white to yellow with the temperature increase through energy transfer between Eu3+ and Dy3+. Additionally, the thermal stability of the Dy3+ single-doped transparent glass ceramics becomes higher after doping Eu3+ ion. (orig.)

  13. Optical thermometry based on luminescence behavior of Dy{sup 3+}-doped transparent LaF{sub 3} glass ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Y.Y. [Nanjing University of Posts and Telecommunications, College of Electronic Science and Engineering, Nanjing (China); Nanjing University of Posts and Telecommunications, College of Science, Nanjing (China); Cheng, S.J.; Wang, X.F. [Nanjing University of Posts and Telecommunications, College of Electronic Science and Engineering, Nanjing (China); Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province, Nanjing, Jiangsu (China); Yan, X.H. [Nanjing University of Posts and Telecommunications, College of Electronic Science and Engineering, Nanjing (China); Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province, Nanjing, Jiangsu (China); Nanjing University of Aeronautics and Astronautics, College of Science, Nanjing (China)

    2015-11-15

    Dy{sup 3+}-doped transparent LaF{sub 3} glass ceramics were fabricated, and its structures of resulting glass ceramics are studied by the X-ray diffraction and transmission electron microscopy. Optical temperature sensing of the resulting glass ceramics in the temperature range from 298 to 523 K is studied based on the down-conversion luminescence of Dy{sup 3+} ion. By using fluorescence intensity ratio method, the {sup 4}I{sub 15/2} and {sup 4}F{sub 9/2} of Dy{sup 3+} ions are verified as thermally coupled levels. A minimum S{sub R} = 1.16 x 10{sup -4} K{sup -1} is obtained at T = 294 K. By doping Eu{sup 3+} ion, the overall emission color of Eu{sup 3+}-Dy{sup 3+} co-doped transparent glass ceramics can be tuned from white to yellow with the temperature increase through energy transfer between Eu{sup 3+} and Dy{sup 3+}. Additionally, the thermal stability of the Dy{sup 3+} single-doped transparent glass ceramics becomes higher after doping Eu{sup 3+} ion. (orig.)

  14. Electrostatic Assembly Preparation of High-Toughness Zirconium Diboride-Based Ceramic Composites with Enhanced Thermal Shock Resistance Performance.

    Science.gov (United States)

    Zhang, Baoxi; Zhang, Xinghong; Hong, Changqing; Qiu, Yunfeng; Zhang, Jia; Han, Jiecai; Hu, PingAn

    2016-05-11

    The central problem of using ceramic as a structural material is its brittleness, which associated with rigid covalent or ionic bonds. Whiskers or fibers of strong ceramics such as silicon carbide (SiC) or silicon nitride (Si3N4) are widely embedded in a ceramic matrix to improve the strength and toughness. The incorporation of these insulating fillers can impede the thermal flow in ceramic matrix, thus decrease its thermal shock resistance that is required in some practical applications. Here we demonstrate that the toughness and thermal shock resistance of zirconium diboride (ZrB2)/SiC composites can be improved simultaneously by introducing graphene into composites via electrostatic assembly and subsequent sintering treatment. The incorporated graphene creates weak interfaces of grain boundaries (GBs) and optimal thermal conductance paths inside composites. In comparison to pristine ZrB2-SiC composites, the toughness of (2.0%) ZrB2-SiC/graphene composites exhibited a 61% increasing (from 4.3 to 6.93 MPa·m(1/2)) after spark plasma sintering (SPS); the retained strength after thermal shock increased as high as 74.8% at 400 °C and 304.4% at 500 °C. Present work presents an important guideline for producing high-toughness ceramic-based composites with enhanced thermal shock properties. PMID:27031536

  15. Some Aspects of the Failure Mechanisms in BaTiO3-Based Multilayer Ceramic Capacitors

    Science.gov (United States)

    Liu, David Donhang; Sampson, Michael J.

    2012-01-01

    The objective of this presentation is to gain insight into possible failure mechanisms in BaTiO3-based ceramic capacitors that may be associated with the reliability degradation that accompanies a reduction in dielectric thickness, as reported by Intel Corporation in 2010. The volumetric efficiency (microF/cm3) of a multilayer ceramic capacitor (MLCC) has been shown to not increase limitlessly due to the grain size effect on the dielectric constant of ferroelectric ceramic BaTiO3 material. The reliability of an MLCC has been discussed with respect to its structure. The MLCCs with higher numbers of dielectric layers will pose more challenges for the reliability of dielectric material, which is the case for most base-metal-electrode (BME) capacitors. A number of MLCCs manufactured using both precious-metal-electrode (PME) and BME technology, with 25 V rating and various chip sizes and capacitances, were tested at accelerated stress levels. Most of these MLCCs had a failure behavior with two mixed failure modes: the well-known rapid dielectric wearout, and so-called 'early failures." The two failure modes can be distinguished when the testing data were presented and normalized at use-level using a 2-parameter Weibull plot. The early failures had a slope parameter of Beta >1, indicating that the early failures are not infant mortalities. Early failures are triggered due to external electrical overstress and become dominant as dielectric layer thickness decreases, accompanied by a dramatic reduction in reliability. This indicates that early failures are the main cause of the reliability degradation in MLCCs as dielectric layer thickness decreases. All of the early failures are characterized by an avalanche-like breakdown leakage current. The failures have been attributed to the extrinsic minor construction defects introduced during fabrication of the capacitors. A reliability model including dielectric thickness and extrinsic defect feature size is proposed in this

  16. In Vitro and In Vivo Evaluation of Zinc-Modified Ca–Si-Based Ceramic Coating for Bone Implants

    OpenAIRE

    Yu, Jiangming; Li, Kai; Zheng, Xuebin; He, Dannong; Ye, Xiaojian; Wang, Meiyan

    2013-01-01

    The host response to calcium silicate ceramic coatings is not always favorable because of their high dissolution rates, leading to high pH within the surrounding physiological environment. Recently, a zinc-incorporated calcium silicate-based ceramic Ca2ZnSi2O7 coating, developed on a Ti-6Al-4V substrate using plasma-spray technology, was found to exhibit improved chemical stability and biocompatibility. This study aimed to investigate and compare the in vitro response of osteoblastic MC3T3-E1...

  17. Heat treatment of pre-hydrolyzed silane increases adhesion of phosphate monomer-based resin cement to glass ceramic

    OpenAIRE

    de Carvalho, Rodrigo Furtado; Caroline COTES; Kimpara, Estevão Tomomitsu; Leite, Fabíola Pessoa Pereira; Özcan, Mutlu

    2015-01-01

    This study evaluated the influence of different forms of heat treatment on a pre-hydrolyzed silane to improve the adhesion of phosphate monomer-based (MDP) resin cement to glass ceramic. Resin and feldspathic ceramic blocks (n=48, n=6 for bond test, n=2 for microscopy) were randomly divided into 6 groups and subject to surface treatments: G1: Hydrofluoric acid (HF) 9.6% for 20 s + Silane + MDP resin cement (Panavia F); G2: HF 9.6% for 20 s + Silane + Heat Treatment (oven) + Panavia F; G3: Sil...

  18. Composite materials based on porous ceramic preform infiltrated by aluminium alloy

    OpenAIRE

    Nagel, A.; A. J. Nowak; M. Kremzer; L.A. Dobrzański

    2007-01-01

    Purpose: The goal of this project is the optimization of manufacturing technology of the ceramic preforms basedon Al2O3 powder manufactured by the pressure infiltration method with liquid metal alloy.Design/methodology/approach: Ceramic preforms were manufactured by the method of sintering of ceramicpowder. The preform material consists of powder Condea Al2O3 CL 2500, however, as the forming factor ofthe structure of canals and pores inside the ceramic agglomerated framework the carbon fibers...

  19. Functionally Graded Materials using Plasma Spray with Nano Structured Ceramic

    International Nuclear Information System (INIS)

    In this paper, nano structured FGM was fabricated using DC plasma spray technique. Nano structured and micro structured powder were used as the feeding powder with steel substrate. The spray parameters was optimized and characterisation of nano-ceramic FGM and micro-ceramic FGM were done using bending test and micro-hardness test. Experimental results have shown that the nano-structured FGM exhibit 20% improvement flexure strength and 10% in hardness. A comparison was made between sintered micro ceramic tile and nano ceramic FGM using simple drop test method.

  20. Functions of Substitution Tilings as a Jacobian

    CERN Document Server

    Solomon, Yaar

    2010-01-01

    In this paper we show that the function defined by a primitive, star shaped substitu- tion tiling of the plane, can be realized as a Jacobian of a biLipschitz homeomorphism of R^2. In particular it holds for any Penrose tiling.

  1. Homological aperiodic tilings of 3-dimensional geometries

    CERN Document Server

    Nowak, Piotr W

    2012-01-01

    We construct the first aperiodic tiles for two amenable 3-dimensional Lie groups: Sol and the Heisenberg group. Our construction relies on the use of higher-dimensional uniformly finite homology. In particular, we settle completely the existence of aperiodic tiles for all of the non-compact geometries of 3-manifolds appearing in the geometrization conjecture.

  2. A special tiling of the rectangle

    OpenAIRE

    Tomei, Carlos; Vieira, Tania

    2001-01-01

    We count tilings of a rectangle of integer sides m-1 and n-1 by a special set of tiles. The result is obtained fron the study of the kernel of the adjacency matrix of an n x n rectangular graph of Z x Z.

  3. Combinatorics and topology of the Robinson tiling

    CERN Document Server

    Gähler, Franz; Savinien, Jean

    2012-01-01

    We study the space of all tilings which can be obtained using the Robinson tiles (this is a two-dimensional subshift of finite type). We prove that it has a unique minimal subshift, and describe it by means of a substitution. This description allows to compute its cohomology groups, and prove that it is a model set.

  4. Status of the ATLAS hadronic tile calorimeter

    International Nuclear Information System (INIS)

    Short status of the Tile Calorimeter project is given. Major achievements in the mechanical construction of the detector modules, their instrumentation, cylinders assembly, as well as the principles of the detector front-end electronics, are described. The ideas of Tile Calorimeter module calibration are presented

  5. Mounting LHCb hadron calorimeter scintillating tiles

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    Scintillating tiles are carefully mounted in the hadronic calorimeter for the LHCb detector. These calorimeters measure the energy of particles that interact via the strong force, called hadrons. The detectors are made in a sandwich-like structure where these scintillator tiles are placed between metal sheets.

  6. Electrochemical desalination of historic Portuguese tiles

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Dias-Ferreira, Celia; Ribeiro, Alexandra B.

    2015-01-01

    Soluble salts cause severe decay of historic Portuguese tiles. Treatment options for removal of the salts to stop the decay are few. The present paper deals with development of a method for electrochemical desalination, where an electric DC field is applied to the tiles. Laboratory experiments were...

  7. Latest news from the Tiles

    CERN Multimedia

    Costanzo, D

    The Tile hadronic calorimeter will be installed in the central region of ATLAS with an inner radius of 2.28 m, an outer radius of 4.25 m, a total length of about 12 m and a weight of about 2300 tons. The calorimeter is mechanically divided in one central barrel and two extended barrels, with a gap in between for the services of the internal part of ATLAS. The construction of the calorimeter is advanced, and installation in the ATLAS pit is foreseen to start in December 2003. After mechanical assembly the modules are instrumented with all the optical components. Scintillating tiles are inserted into the slots, and the read-out Wave Length Shifting fibers are coupled to scintillators and bundled to achieve the quasi-projective cell geometry of the calorimeter. The final modules are stored in bldg 185, shown in the first photo, and in bldg 175 at CERN. The barrel modules are mechanically assembled in Dubna and then transported to CERN to be optically instrumented, while the extended barrels are constructed in t...

  8. A new lutetia-based ceramic scintillator for X-ray imaging

    CERN Document Server

    Lempicki, A; Szupryczynski, P; Lingertat, H; Nagarkar, V V; Tipnis, S V; Miller, S R

    2002-01-01

    We report a new scintillator based on a transparent ceramic of Lu sub 2 O sub 3 :Eu. The material has an extremely high density of 9.4 g/cm sup 3 , a light output comparable to CsI:Tl, and a narrow band emission at 610 nm that falls close to the maximum of the response curve of CCDs. Pixelation of the scintillator to prevent lateral spread of light enhances the spatial and contrast resolution, providing imaging performance that equals or surpasses all other currently known scintillators. Upon further development of readout technologies to take full advantage of its transparency, the new scintillator should play a major role in digital radiographic systems.

  9. A General Reliability Model for Ni-BaTiO3-Based Multilayer Ceramic Capacitors

    Science.gov (United States)

    Liu, Donhang

    2014-01-01

    The evaluation of multilayer ceramic capacitors (MLCCs) with Ni electrode and BaTiO3 dielectric material for potential space project applications requires an in-depth understanding of their reliability. A general reliability model for Ni-BaTiO3 MLCC is developed and discussed. The model consists of three parts: a statistical distribution; an acceleration function that describes how a capacitor's reliability life responds to the external stresses, and an empirical function that defines contribution of the structural and constructional characteristics of a multilayer capacitor device, such as the number of dielectric layers N, dielectric thickness d, average grain size, and capacitor chip size A. Application examples are also discussed based on the proposed reliability model for Ni-BaTiO3 MLCCs.

  10. Thermoluminescence dating (TL-dating): measurement and accuracy factors in archaeological dating of ceramic base materials

    International Nuclear Information System (INIS)

    Thermoluminescence dating is one of the known techniques that have been established in many laboratories across the region. This technique is capable of dating the archaeological ceramic base materials and provide an absolute measurement with an accuracy of ±15%. The study involves the dating of pottery from a historical site at Sungai Mas, Mukim Kota, Daerah Kuala Muda, Kedah. Pieces of broken pottery of archaeological sample excavated by the Museum Department and Antiquity (JMA) have been dated using the thermoluminescence detector (TLD) techniques at MINT laboratory. A TLD dosemeter of LiF chips is used for the measurement of background and sample dose measurement. The preparation of sample and the calibration techniques for the estimation of palaedose or dose presented in the sample since distant past is established. Results indicate that the samples are in the era of civilization from 200 BP to 1600 BP. Error factors associated in the measurement procedures were identified and discussed. (Author)

  11. High-strength zirconium diboride-based ceramic composites consolidated by low-temperature hot pressing

    Directory of Open Access Journals (Sweden)

    Shuqi Guo and Yutaka Kagawa

    2012-01-01

    Full Text Available Two compositions of ZrB2-based ceramic composites containing Si3N4, Al2O3 and Y2O3 have been hot-pressed at different temperatures between 1673 and 1773 K for 60 min in vacuum. The densification behavior of the composites was examined during the sintering process. The microstructures of the composites were characterized by scanning electron microscopy, and the crystalline phases were identified by x-ray diffraction. The effects of Al2O3 and Y2O3 additives on the densification behavior and flexural strength were assessed. A relative density of ~95% was obtained after sintering at 1723 K or higher temperatures. The microstructures of the composites consisted of (Zr,YB2, α-Si3N4 and Y3(Al,Si5O12 phases. The room-temperature flexural strength increased with the amount of additives and approached 1 GPa.

  12. Physics-Based Design Tools for Lightweight Ceramic Composite Turbine Components with Durable Microstructures

    Science.gov (United States)

    DiCarlo, James A.

    2011-01-01

    Under the Supersonics Project of the NASA Fundamental Aeronautics Program, modeling and experimental efforts are underway to develop generic physics-based tools to better implement lightweight ceramic matrix composites into supersonic engine components and to assure sufficient durability for these components in the engine environment. These activities, which have a crosscutting aspect for other areas of the Fundamental Aero program, are focusing primarily on improving the multi-directional design strength and rupture strength of high-performance SiC/SiC composites by advanced fiber architecture design. This presentation discusses progress in tool development with particular focus on the use of 2.5D-woven architectures and state-of-the-art constituents for a generic un-cooled SiC/SiC low-pressure turbine blade.

  13. Elliptically distributed lozenge tilings of a hexagon

    CERN Document Server

    Betea, Dan

    2011-01-01

    We present a detailed study of a 4 parameter family of elliptic weights on tilings of a hexagon introduced by Borodin, Gorin and Rains, and generalize some of their results. In the process, we connect the combinatorics of the model with the theory of elliptic special functions. We first analyze some properties of the measure and introduce canonical coordinates that are useful for combinatorially interpreting results. We then show how the computed $n$-point function (called the elliptic Selberg density) and transitional probabilities connect to the theory of $BC_n$-symmetric multivariate elliptic special functions and difference operators discovered by Rains. In particular, the difference operators intrinsically capture the combinatorial model under study, while the elliptic Selberg density is a generalization (deformation) of probability distributions pervasive in the theory of random matrices and interacting particle systems. Based on quasi-commutation relations between elliptic difference operators, we cons...

  14. Floor tile and mastic removal project report

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    A test program was developed and coordinated with State and Federal Regulators and carried out at Fort Sill, Oklahoma. This program was carefully designed to create the worst conditions in order to evaluate whether asbestos fibers are released when asbestos containing floor tile and mastic are removed. There were over 1,000 samples taken and analyzed during the execution of the program. The conclusions reached were based upon analysis of the critical samples using the Transmission Electron Microscope (TEM) technology. Additionally, the TEM procedures were used to evaluate personnel samples to determine whether those fibers found were asbestos or other materials. Most of the (TEM) samples were analyzed by the US Environmental Protection Agency (EPA) Risk Reduction Engineering Laboratory in Cincinnati, Ohio.

  15. Performance of the ATLAS hadronic Tile calorimeter

    CERN Document Server

    Bartos, Pavol; The ATLAS collaboration

    2016-01-01

    The Tile Calorimeter (TileCal) of the ATLAS experiment at the LHC is the central hadronic calorimeter designed for energy reconstruction of hadrons, jets, tau-particles and missing transverse energy. TileCal is a scintillator-steel sampling calorimeter and it covers the region of pseudorapidity < 1.7. The scintillation light produced in the scintillator tiles is transmitted to photomultiplier tubes (PMTs). Signals from the PMTs are amplified, shaped and digitized by sampling the signal every 25 ns. Each stage of the signal production from scintillation light to the signal reconstruction is monitored and calibrated. Results on the calorimeter operation and performance are presented, including the calibration, stability, absolute energy scale, uniformity and time resolution. These results show that the TileCal performance is within the design requirements and has given essential contribution to reconstructed objects and physics results.

  16. Consistency and Derangements in Brane Tilings

    CERN Document Server

    Hanany, Amihay; Ramgoolam, Sanjaye; Seong, Rak-Kyeong

    2015-01-01

    Brane tilings describe Lagrangians (vector multiplets, chiral multiplets, and the superpotential) of four dimensional $\\mathcal{N}=1$ supersymmetric gauge theories. These theories, written in terms of a bipartite graph on a torus, correspond to worldvolume theories on $N$ D$3$-branes probing a toric Calabi-Yau threefold singularity. A pair of permutations compactly encapsulates the data necessary to specify a brane tiling. We show that geometric consistency for brane tilings, which ensures that the corresponding quantum field theories are well behaved, imposes constraints on the pair of permutations, restricting certain products constructed from the pair to have no one-cycles. Permutations without one-cycles are known as derangements. We illustrate this formulation of consistency with known brane tilings. Counting formulas for consistent brane tilings with an arbitrary number of chiral bifundamental fields are written down in terms of delta functions over symmetric groups.

  17. Lightweight Ceramic Composition of Carbon Silicon Oxygen and Boron

    Science.gov (United States)

    Leiser, Daniel B. (Inventor); Hsu, Ming-Ta (Inventor); Chen, Timothy S. (Inventor)

    1997-01-01

    Lightweight, monolithic ceramics resistant to oxidation in air at high temperatures are made by impregnating a porous carbon preform with a sol which contains a mixture of tetraethoxysilane, dimethyldiethoxysilane and trimethyl borate. The sol is gelled and dried on the carbon preform to form a ceramic precursor. The precursor is pyrolyzed in an inert atmosphere to form the ceramic which is made of carbon, silicon, oxygen and boron. The carbon of the preform reacts with the dried gel during the pyrolysis to form a component of the resulting ceramic. The ceramic is of the same size, shape and form as the carbon precursor. Thus, using a porous, fibrous carbon precursor, such as a carbon felt, results in a porous, fibrous ceramic. Ceramics of the invention are useful as lightweight tiles for a reentry spacecraft.

  18. Strontium chloroapatite based glass-ceramics composites for nuclear waste immobilisation

    International Nuclear Information System (INIS)

    Apatites are naturally occurring minerals with a general formula of M10(PO4)6X2, (M= Ca, Sr, Ba, X= OH, Cl, F) with a hexagonal crystal structure (S.G :P63/m) and can accommodate alkaline earth and various other aliovalent cations and anions into its crystal structure. Apatites are also known to have high resistance to leaching of the constituent elements under geological conditions. It may not often be possible to immobilize the whole spectrum of the radioactive waste in a single phase M10(PO4)6Cl2, then a combination of M-chloroapatite encapsulated in borosilicate glass (BSG) can immobilize most of the radwaste elements in the composite glass-ceramic matrix (glass bonded chloroapatite), thus utilizing the immobilizing efficiency of both the ceramic phase and glass. In the present study, the synthesis, characterization and thermo-physical property measurements of the Sr-chloroapatite (SrApCI) and some glass-bonded composites based on it have been investigated. The Sr-chloroapatite glass-ceramics were prepared by solid state reactions among stoichiometric concentrations of apatite forming reagents, 20 wt. % borosilicate glass (BSG), and known concentrations (10, 13 and 16 wt. %) of a simulated waste in chloride form. The products were characterized by XRD to confirm the formation of Sr10(PO4)6Cl2 and glass bonded-chloroapatite composites. The surface morphology and qualitative chemical composition of the powders were examined by SEM and EDX. Thermal expansion and glass transition temperature of the matrices were measured by dilatometry. Glass transition temperature of the glass-bonded composites was also examined by differential scanning calorimetry and differential thermal analysis. The 10-16 wt.% waste loaded matrices showed similar thermal expansion as that of SrApCI, indicating the thermal stability of the matrix to chloride waste immobilization. The glass transition temperature of the waste loaded matrices decreases on increasing the waste loading. The

  19. Synthesis and mechanical characterization of PZT/Sr based composite ceramics with addition of Si3N4

    International Nuclear Information System (INIS)

    In the Underwater Acoustics field, piezoelectric ceramics are the most usually employed materials for the conversion of mechanical energy (acoustic signal) into electric energy (electric signal) and vice-versa, in sensors (hydrophones) or hydroacoustic projectors. In the development of new compositions for these applications, piezoelectric performance is generally prioritized, to the expense of its mechanical properties. With this in mind, the object of this work was to study the effects of the addition of Si3N4 in the mechanical properties of PZT-Sr based electronic ceramics. Thus, a novel piezoelectric ceramic with the addition of small percentages in weight (0;0.1;1;3 and 5) of the structural ceramic Si3N4 was successfully processed by the oxide mixing route ; the compounds were sintered in a conventional at 1200 deg C for 2h. The densities of the compounds thus obtained for the different percentages of Si3N4 ranged from 55 to 97% and decreased with the increase of the content of Si3N4. Presence of equiaxial grains with normal growth was observed in all samples. MEV/EDS analysis of the micro-structures of the compositions detected the presence of a second phase rich in Zr, confirmed by DRX, which is a result of large quantities of volatilized PbO; the sintered pieces had their mechanical properties investigated by ultra-sonic inspection. It was observed that, among the sintered compositions, the PZT-Sr ceramic with 0.1% Si3N4 presented the smallest value for Young's Modulus E and Shear Modulus G, 75 Gpa and 28 Gpa, respectively. The Poisson's Coefficients ν tended to decrease with the increase of Si3N4 added to the PZT-Sr ceramic, indicating, thus, that the added compound may be used to adjust the mechanical properties of the material. (author)

  20. A comparison of shear bond strength of ceramic and resin denture teeth on different acrylic resin bases

    OpenAIRE

    Corsalini, Massimo; Venere, Daniela Di; Pettini, Francesco; Stefanachi, Gianluca; Catapano, Santo; Boccaccio, Antonio; Lamberti, Luciano; Pappalettere, Carmine; Carossa, Stefano

    2014-01-01

    The purpose of this study is to compare the shear bond strength of different resin bases and artificial teeth made of ceramic or acrylic resin materials and whether tooth-base interface may be treated with aluminium oxide sandblasting. Experimental measurements were carried on 80 specimens consisting of a cylinder of acrylic resin into which a single tooth is inserted. An ad hoc metallic frame was realized to measure the shear bond strength at the tooth-base interface. A complete factorial pl...

  1. Conduction in a two-phase plane with diamond-shaped tiling

    Science.gov (United States)

    Helsing, Johan; Grimvall, Göran; Bao, Ke-da

    1991-07-01

    The effective conductivity of a two-phase two-dimensional composite with diamond-shaped tiling is considered. This analysis, based on a projection of the boundary conditions on linear combinations of solutions to the electrostatic equation that are orthonormal on the boundary, generalizes results by Keller [J. Math. Phys. 28, 2516 (1987)] and others. Numerical results are given for several conductivity ratios of the two phases and for varying obtuse angles of the tiles. Special emphasis is given to very large and very small conductivity differences, and very elongated tiles.

  2. Analysis of Tile-Reinforced Composite Armor. Part 1; Advanced Modeling and Strength Analyses

    Science.gov (United States)

    Davila, C. G.; Chen, Tzi-Kang; Baker, D. J.

    1998-01-01

    The results of an analytical and experimental study of the structural response and strength of tile-reinforced components of the Composite Armored Vehicle are presented. The analyses are based on specialized finite element techniques that properly account for the effects of the interaction between the armor tiles, the surrounding elastomers, and the glass-epoxy sublaminates. To validate the analytical predictions, tests were conducted with panels subjected to three-point bending loads. The sequence of progressive failure events for the laminates is described. This paper describes the results of Part 1 of a study of the response and strength of tile-reinforced composite armor.

  3. Polymorphic Phase Transition and Temperature Coefficient of Capacitance of Alkaline Niobate Based Ceramics

    Directory of Open Access Journals (Sweden)

    In-Ho Im

    2013-04-01

    Full Text Available 0.95(Na0.5K0.5NbO3-0.05BaTiO3 + 0.2wt% Ag2O (hereafter, No excess NKN ceramics and 0.95(Na0.5K0.5NbO3-0.05BaTiO3 + 0.2wt% Ag2O with excess (Na0.5K0.5NbO3 (hereafter, Excess NKN were fabricated by the conventionalsolid state sintering method, and their phase transition properties and dielectric properties were investigated. Thecrystalline structure of No excess NKN ceramics and Excess NKN ceramics were shown characteristics of polymorphicphase transition (hereafter, PPT, especially shift from the orthorhombic to tetragonal phase by increasing sinteringtemperature range from 1,100℃ to 1,200℃. Also, the temperature coefficient of capacitance (hereafter, TCC ofNo excess NKN ceramics and Excess NKN ceramics from -40℃ to 100℃ was measured to evaluate temperaturestability for applications in cold regions. The TCC of No excess NKN and Excess NKN ceramics showed positive TCCcharacteristics at a temperature range from -40℃ to 100℃. Especially, Excess NKN showed a smaller TCC gradientthan those of Excess NKN ceramics in range from -40℃ to 100℃. Therefore, NKN piezoelectric ceramics combinedwith temperature compensated capacitor having negative temperature characteristics is desired for usage in coldregions.

  4. THz imaging of majolica tiles and biological attached marble fragments

    Science.gov (United States)

    Catapano, Ilaria; Soldovieri, Francesco

    2016-04-01

    Devices exploiting waves in the frequency range from 0.1 THz to 10 THz (corresponding to a free-space wavelength ranging from 30 μm to 3 mm) deserve attention as diagnostic technologies for cultural heritage. THz waves are, indeed, non-ionizing radiations capable of penetrating into non-metallic materials, which are opaque to both visible and infrared waves, without implying long term risks to the molecular stability of the exposed objects and humans. Moreover, THz surveys involve low poewr probing waves, are performed without contact with the object and, thanks to the recent developments, which have allowed the commercialization of compact, flexible and portable systems, maybe performed in loco (i.e. in the place where the artworks are usually located). On the other hand, THz devices can be considered as the youngest among the sensing and imaging electromagnetic techniques and their actual potentialities in terms of characterization of artworks is an ongoing research activity. As a contribution within this context, we have performed time of flight THz imaging [1,2] on ceramic and marble objects. In particular, we surveyed majolica tiles produced by Neapolitan ceramists in the 18th and 19th centuries with the aim to gather information on their structure, constructive technique and conservation state. Moreover, we investigated a Marmo di Candoglia fragment in order to characterize the biological attach affecting it. All the surveys were carried out by using the Fiber-Coupled Terahertz Time Domain System (FICO) developed by Z-Omega and available at the Institute of Electromagnetic Sensing of the Environment (IREA). This system is equipped with fiber optic coupled transmitting and receiving probes and with an automatic positioning system enabling to scan a 150 mm x 150 mm area under a reflection measurement configuration. Based on the obtained results we can state that the use of THz waves allows: - the reconstruction of the object topography; - the geometrical

  5. Microbial deterioration of artistic tiles from the façade of the Grande Albergo Ausonia & Hungaria (Venice, Italy).

    Science.gov (United States)

    Giacomucci, Lucia; Bertoncello, Renzo; Salvadori, Ornella; Martini, Ilaria; Favaro, Monica; Villa, Federica; Sorlini, Claudia; Cappitelli, Francesca

    2011-08-01

    The Grande Albergo Ausonia & Hungaria (Venice Lido, Italy) has an Art Nouveau polychrome ceramic coating on its façade, which was restored in 2007. Soon after the conservation treatment, many tiles of the façade decoration showed coloured alterations putatively attributed to the presence of microbial communities. To confirm the presence of the biological deposit and the stratigraphy of the Hungaria tiles, stereomicroscope, optical and environmental scanning electron microscope observations were made. The characterisation of the microbial community was performed using a PCR-DGGE approach. This study reported the first use of a culture-independent approach to identify the total community present in biodeteriorated artistic tiles. The case study examined here reveals that the coloured alterations on the tiles were mainly due to the presence of cryptoendolithic cyanobacteria. In addition, we proved that the microflora present on the tiles was generally greatly influenced by the environment of the Hungaria hotel. We found several microorganisms related to the alkaline environment, which is in the range of the tile pH, and related to the aquatic environment, the presence of the acrylic resin Paraloid B72® used during the 2007 treatment and the pollutants of the Venice lagoon. PMID:21286701

  6. Fundamental ultrasonic wave propagation studies in a model thermal protection system (porous tiles bonded to aluminum bulkhead)

    Science.gov (United States)

    Kundu, Tribikram; Reibel, Richard; Jata, Kumar V.

    2006-03-01

    A model thermal protection system (TPS) was designed by bonding ceramic porous tiles to 2.2 and 3.5 mm thick 2124-T351 aluminum alloy plates. One of the goals of the present work was to investigate the potential of detecting simulated defects using guided waves. Simulated defects consisted of cracks, voids and delaminations at the tile-substrate interface. Cracks and voids were introduced into the porous tiles during the fabrication of the TPS. Delamination was created by cutting the gluing tape between the tile and the aluminum substrate. Guided wave propagation studies were conducted using the pitch-catch approach, while changing the angle of strike and the frequency of the transducer excitation to generate the appropriate guided wave mode. The receiver was placed at a distance so that only the guided waves were received during the immersion experiment. The delamination defect could be conclusively detected, however the presence of the imperfect bond between the tiles and the substrate interfered with the detection of the simulated cracks and voids in the porous tiles.

  7. Wollastonite based-Chemically Bonded Phosphate Ceramics with lead oxide contents under gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Colorado, H.A., E-mail: hcoloradolopera@ucla.edu [University of California, Materials Science and Engineering Department, Los Angeles, CA (United States); Universidad de Antioquia, Mechanical Engineering Department, Medellin (Colombia); Pleitt, J. [Missouri University of Science and Technology, Nuclear Engineering Department, MO (United States); Hiel, C. [Composite Support and Solutions Inc., San Pedro, CA (United States); MEMC, University of Brussels (VUB), Brussels (Belgium); Yang, J.M.; Hahn, H.T. [University of California, Materials Science and Engineering Department, Los Angeles, CA (United States); Castano, C.H. [Missouri University of Science and Technology, Nuclear Engineering Department, MO (United States)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer The effect of PbO on the attenuation coefficient of Wollastonite based-CBPCs is presented. Black-Right-Pointing-Pointer The effect of PbO on the compressive strength and setting time of Wollastonite based-CBPCs is presented. Black-Right-Pointing-Pointer The attenuation coefficient of the CBPC was improved (between 32% to 193.8%) by the addition of Pb. - Abstract: The shielding properties to gamma rays as well as the effect of lead concentration incorporated into Chemically Bonded Phosphate Ceramics (CBPCs) composites are presented. The Wollastonite-based CBPC was fabricated by mixing a patented aqueous phosphoric acid formulation with Wollastonite powder. CBPC has been proved to be good structural material, with excellent thermal resistant properties, and research already showed their potential for radiation shielding applications. Wollastonite-based CBPC is a composite material itself with several crystalline and amorphous phases. Irradiation experiments were conducted on different Wollastonite-based CBPCs with lead oxide. Radiation shielding potential, attenuation coefficients in a broad range of energies pertinent to engineering applications and density experiments showing the effect of the PbO additions (to improve gamma shielding capabilities) are also presented. Microstructure was identified by using scanning electron microscopy and X-ray diffraction.

  8. Análise da co-utilização do resíduo do beneficiamento do caulim e serragem de granito para produção de blocos e telhas cerâmicos Analysis of the use of kaolin processing waste and granite sawing waste together for the production of ceramic bricks and roof tiles

    Directory of Open Access Journals (Sweden)

    R. R. Menezes

    2007-06-01

    high amounts of wastes. This work has as aim the characterization of the kaolin processing waste and granite sawing waste and the evaluation of their use together for the production of bricks and roof tiles. The wastes were characterized by chemical composition determination, X-ray diffraction, differential thermal and gravimetric analyses, particle size distribution determination, and morphological analysis by electronic scanning microscopy. Several formulations were prepared and samples bodies were prepared by extrusion. The sample bodies were fired at 800, 900 and 1000 ºC. Fired samples were characterized in terms of water absorption and mechanical strength. The results showed that the kaolin waste is composed by kaolinite, mica and quartz and that the granite waste is composed by quartz, mica, albite and calcite, and that, the wastes have significantly distinct particles size distributions. It could also be concluded that are possible incorporations of up to 50% of wastes in formulation for the production of ceramic bricks and roof tiles, and that, the use of the kaolin waste and granite waste together provide better physical properties than those observed in samples bodies with incorporations of only kaolin waste.

  9. Application of non-porous alumina based ceramics as structural material for devices handling tritium at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Yukhimchuk, A.A.; Maksimkin, I.P.; Baluev, V.V.; Boitsov, I.E.; Vertey, A.V.; Malkov, I.L.; Musyaev, R.K.; Popov, V.V.; Sitdikov, D.T. [Russian Federal Nuclear Centre, All-Russian Research Institute of Experimental Physics - RFNC-VNIIEF, Sarov (Russian Federation); Khapov, A.S.; Grishechkin, S.K.; Kiselev, V.G. [All-Russian Research Institute of Automatics - FSUE-VNIIA, Moscow (Russian Federation)

    2015-03-15

    The article presents results of comparative tests for the determination of deuterium fluxes permeating through walls of austenitic stainless steel AISI304 (DIN 1.4301) chamber and Al{sub 2}O{sub 3} based ceramic F99.7 chamber. Both chambers represent a piece of φ(ext)=26*φ(int)=22*117 mm{sup 3} tube with spherical bottom ending. It is shown that at 773 K and deuterium pressure of 1200 mbar the permeated deuterium flux through the stainless steel chamber constituted 8*10{sup -5} cm{sup 3}/s, while the flux through ceramic one it did not exceed the sensitivity of the measurement method threshold, namely about 1.5*10{sup -7} cm{sup 3}/s. The ceramic chamber turned out to survive more than 10{sup 3} cycles of heating up to 773 K with no damages. It did not lose its tightness up to 10 bar of internal deuterium pressure. The authors also present test results of a prototype bed for reversible tritium storage. The bed's case was made of alumina based ceramic F99.7, titanium being used as tritide making metal and high frequency induction used for heating the tritide metal. (authors)

  10. Application of non-porous alumina based ceramics as structural material for devices handling tritium at elevated temperatures

    International Nuclear Information System (INIS)

    The article presents results of comparative tests for the determination of deuterium fluxes permeating through walls of austenitic stainless steel AISI304 (DIN 1.4301) chamber and Al2O3 based ceramic F99.7 chamber. Both chambers represent a piece of φ(ext)=26*φ(int)=22*117 mm3 tube with spherical bottom ending. It is shown that at 773 K and deuterium pressure of 1200 mbar the permeated deuterium flux through the stainless steel chamber constituted 8*10-5 cm3/s, while the flux through ceramic one it did not exceed the sensitivity of the measurement method threshold, namely about 1.5*10-7 cm3/s. The ceramic chamber turned out to survive more than 103 cycles of heating up to 773 K with no damages. It did not lose its tightness up to 10 bar of internal deuterium pressure. The authors also present test results of a prototype bed for reversible tritium storage. The bed's case was made of alumina based ceramic F99.7, titanium being used as tritide making metal and high frequency induction used for heating the tritide metal. (authors)

  11. Ceramic Technology Project

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    The Ceramic Technology Project was developed by the USDOE Office of Transportation Systems (OTS) in Conservation and Renewable Energy. This project, part of the OTS's Materials Development Program, was developed to meet the ceramic technology requirements of the OTS's automotive technology programs. Significant accomplishments in fabricating ceramic components for the USDOE and NASA advanced heat engine programs have provided evidence that the operation of ceramic parts in high-temperature engine environments is feasible. These programs have also demonstrated that additional research is needed in materials and processing development, design methodology, and data base and life prediction before industry will have a sufficient technology base from which to produce reliable cost-effective ceramic engine components commercially. A five-year project plan was developed with extensive input from private industry. In July 1990 the original plan was updated through the estimated completion of development in 1993. The objective is to develop the industrial technology base required for reliable ceramics for application in advanced automotive heat engines. The project approach includes determining the mechanisms controlling reliability, improving processes for fabricating existing ceramics, developing new materials with increased reliability, and testing these materials in simulated engine environments to confirm reliability. Although this is a generic materials project, the focus is on the structural ceramics for advanced gas turbine and diesel engines, ceramic bearings and attachments, and ceramic coatings for thermal barrier and wear applications in these engines. To facilitate the rapid transfer of this technology to US industry, the major portion of the work is being done in the ceramic industry, with technological support from government laboratories, other industrial laboratories, and universities.

  12. Lozenge Tilings with Free Boundaries

    Science.gov (United States)

    Panova, Greta

    2015-11-01

    We study lozenge tilings of a domain with partially free boundary. In particular, we consider a trapezoidal domain (half-hexagon), s.t. the horizontal lozenges on the long side can intersect it anywhere to protrude halfway across. We show that the positions of the horizontal lozenges near the opposite flat vertical boundary have the same joint distribution as the eigenvalues from a Gaussian Unitary Ensemble (the GUE-corners/minors process). We also prove the existence of a limit shape of the height function, which is also a vertically symmetric plane partition. Both behaviors are shown to coincide with those of the corresponding doubled fixed boundary hexagonal domain. We also consider domains where the different sides converge to {∞} at different rates and recover again the GUE-corners process near the boundary.

  13. Microfabrication of a Novel Ceramic Pressure Sensor with High Sensitivity Based on Low-Temperature Co-Fired Ceramic (LTCC Technology

    Directory of Open Access Journals (Sweden)

    Chen Li

    2014-06-01

    Full Text Available In this paper, a novel capacitance pressure sensor based on Low-Temperature Co-Fired Ceramic (LTCC technology is proposed for pressure measurement. This approach differs from the traditional fabrication process for a LTCC pressure sensor because a 4J33 iron-nickel-cobalt alloy is applied to avoid the collapse of the cavity and to improve the performance of the sensor. Unlike the traditional LTCC sensor, the sensitive membrane of the proposed sensor is very flat, and the deformation of the sensitivity membrane is smaller. The proposed sensor also demonstrates a greater responsivity, which reaches as high as 13 kHz/kPa in range of 0–100 kPa. During experiments, the newly fabricated sensor, which is only about 6.5 cm2, demonstrated very good performance: the repeatability error, hysteresis error, and nonlinearity of the sensor are about 4.25%, 2.13%, and 1.77%, respectively.

  14. A Note on Space Tiling Zonotopes

    OpenAIRE

    Vallentin, Frank

    2004-01-01

    In 1908 Voronoi conjectured that every convex polytope which tiles space face-to-face by translations is affinely equivalent to the Dirichlet-Voronoi polytope of some lattice. In 1999 Erdahl proved this conjecture for the special case of zonotopes. A zonotope is a projection of a regular cube under some affine transformation. In 1975 McMullen showed several equivalent conditions for a zonotope to be a space tiling zonotope, i.e. a zonotope which admits a face-to-face tiling of space by transl...

  15. Outer boundaries of self-similar tiles

    OpenAIRE

    Drenning, Shawn; Palagallo, Judith; Price, Thomas; Strichartz, Robert S.

    2005-01-01

    There are many examples of self-similar tiles that are connected, but whose interior is disconnected. For such tiles we show that the boundary of a component of the interior may be decomposed into a finite union of pieces, each similar to a subset of the outer boundary of the tile. This is significant because the outer boundary typically has lower dimension than the full boundary. We describe a method to realize the outer boundary as the invariant set of a graph-directed iterated function sys...

  16. Growth Rates in the Quaquaversal Tiling

    OpenAIRE

    Draco, Brimstone; Sadun, Lorenzo; Van Wieren, Douglas

    1998-01-01

    Conway and Radin's ``quaquaversal'' tiling of R^3 is known to exhibit statistical rotational symmetry in the infinite volume limit. A finite patch, however, cannot be perfectly isotropic, and we compute the rates at which the anisotropy scales with size. In a sample of volume N, tiles appear in O(N^{1/6}) distinct orientations. However, the orientations are not uniformly populated. A small (O(N^{1/84})) set of these orientations account for the majority of the tiles. Furthermore, these orient...

  17. The TileCal Laser Calibration System

    Science.gov (United States)

    Giangiobbe, Vincent; On Behalf Of The Atlas Tile Calorimeter Group

    TileCal is the central hadronic calorimeter of the ATLAS detector operating at LHC. It is a sampling calorimeter whose active material is made of scintillating plastic tiles. Scintillation light is read by photomultipliers. A Laser system is used to monitor their gain stability. During dedicated calibration runs the Laser system sends via long optical fibers, a monitored amount of light simultaneously to all the ≈10000 photomultipliers of TileCal. This note describes two complementary methods to measure the stability of the photomultipliers gain using the Laser calibration runs. The results of validation tests are presented for both methods and theirrespective performances and limitations are discussed.

  18. Remotely replaceable tokamak plasma limiter tiles

    Science.gov (United States)

    Gallix, R.

    1987-12-09

    U-shaped tiles placed end-to-end over a pair of parallel runners have two rods which engage L-shaped slots. A sliding bar between the runners has grooves with clips to retain the rods pressed into receiving legs of the L-shaped slots in the runners. Sliding the bar in the direction of retaining legs of the L-shaped slots latches the tiles in place over the wall. Resilient contact strips under the parallel sides of the U-shaped tile assure thermal and electrical contact with the wall. 6 figs.

  19. Structure, solubility and bioactivity in TiO2-doped phosphate-based bioglasses and glass-ceramics

    International Nuclear Information System (INIS)

    Phosphate-based bioactive glasses in addition to TiO2 (x = 0-2.5 mol%) were prepared by melt quenching technique. Glass-ceramics were prepared by controlled two-step thermal treatment of the as-prepared phosphate bioglasses at their nucleation and crystallisation temperatures. X-ray diffraction (XRD) analysis was used to explore the amorphous and crystalline nature of materials. The presence of calcium phosphate crystals like NaPO3, α, β-Ca2P2O7, α,β-Ca3(PO4)2 and Na5Ti(PO4)3 plays a dominant role in glass-ceramics. The structural changes were analyzed by density and Tg measurements. The degradation process in deionised water (DIW) was observed by pH and weight loss measurements. It was interesting to note that the highest solubility phosphate glasses become stiffer to degradation with increasing TiO2 content. Addition of TiO2 leads to densify the glass structure and interconnect the cross-linkages in the network. Chemical durability of glass-ceramics in DIW purely depends on the formed crystalline as well as the residual glassy phases. The formation of a biologically active layer on the surface of glasses and glass-ceramics were investigated by in vitro studies through XRD analysis.

  20. Tilings of the Sphere by Edge Congruent Pentagons

    OpenAIRE

    Cheuk, Ka Yue; Cheung, Ho Man; Yan, Min

    2013-01-01

    We study edge-to-edge tilings of the sphere by edge congruent pentagons, under the assumption that there are tiles with all vertices having degree 3. We develop the technique of neighborhood tilings and apply the technique to completely classify edge congruent earth map tilings.