A Harsh Environment-Oriented Wireless Passive Temperature Sensor Realized by LTCC Technology

Directory of Open Access Journals (Sweden)

Qiulin Tan

2014-03-01

Full Text Available To meet measurement needs in harsh environments, such as high temperature and rotating applications, a wireless passive Low Temperature Co-fired Ceramics (LTCC temperature sensor based on ferroelectric dielectric material is presented in this paper. As a LC circuit which consists of electrically connected temperature sensitive capacitor and invariable planar spiral inductor, the sensor has its resonant frequency shift with the variation in temperature. Within near-filed coupling distance, the variation in resonant frequency of the sensor can be detected contactlessly by extracting the impedance parameters of an external antenna. Ferroelectric ceramic, which has temperature sensitive permittivity, is used as the dielectric. The fabrication process of the sensor, which differs from conventional LTCC technology, is described in detail. The sensor is tested three times from room temperature to 700 °C, and considerable repeatability and sensitivity are shown, thus the feasibility of high performance wireless passive temperature sensor realized by LTCC technology is demonstrated.

Gain-enhanced LTCC system-on-package for automotive UMRR applications

KAUST Repository

Ghaffar, Farhan A.

2012-07-28

A novel Low Temperature Co-fired Ceramic (LTCC) based SoP for automotive radar applications is presented. For the first time a combination of a relatively low dielectric constant LTCC substrate and a high dielectric constant LTCC superstrate has been incorporated to enhance the overall gain of the module. The superstrate can provide additional protection to the integrated circuits (IC) in the harsh automotive environment. A custom cavity in the LTCC substrate can accommodate the IC, which feeds an aperture coupled patch antenna array. The cavity is embedded below the ground plane that acts as a shield for the IC from antenna radiation. It is estimated that with mere 10 dBm of transmitted RF power the miniature SoP module (sized 2.0 cm × 2.0 cm × 0.22 cm) can communicate up to 67 m. The design\\'s compactness, robustness, transmission power and resultant communication range are highly suitable for Universal Medium Range Radar (UMRR) applications. © 2010 IEEE.

Design, fabrication and characterization of LTCC-based electromagnetic microgenerators

International Nuclear Information System (INIS)

Gierczak, M; Markowski, P; Dziedzic, A

2016-01-01

Design, manufacturing process and properties of electromagnetic microgenerators fabricated in LTCC (Low Temperature Co-fired Ceramics) technology are presented in this paper. Electromagnetic microgenerators consist of planar coils spatially arranged on several layers of LTCC and of a multipole permanent magnet. Two different patterns of coils with 2-, 8-,10- and 12-layers and outer diameter of 50 mm were designed and fabricated. Silver-based pastes ESL 903-A or DuPont 6145 were used. In order to estimate the inductance of a single spatial coil the Greenhouse (self-inductance) and Hoer (mutual inductance) calculation methods were used. To verify the calculation results a single-layer coil was fabricated for each pattern and its inductance was measured using the precision RLC Meter. Fabricated LTCC microgenerators with embedded coils allow to generate voltage higher than ten volts and the electrical output power of approximately 600 mW at the rotor rotation speed of 12 thousands rpm. The self-made system was used for characterization of LTCC-based electromagnetic microgenerators. (paper)

Synthesis of Nanocrystalline CaWO4 as Low-Temperature Co-fired Ceramic Material: Processing, Structural and Physical Properties

Science.gov (United States)

Vidya, S.; Solomon, Sam; Thomas, J. K.

2013-01-01

Nanocrystalline scheelite CaWO4, a promising material for low-temperature co-fired ceramic (LTCC) applications, has been successfully synthesized through a single-step autoignition combustion route. Structural analysis of the sample was performed by powder x-ray diffraction (XRD), Fourier-transform infrared spectroscopy, and Raman spectroscopy. The XRD analysis revealed that the as-prepared sample was single phase with scheelite tetragonal structure. The basic optical properties and optical constants of the CaWO4 nanopowder were studied using ultraviolet (UV)-visible absorption spectroscopy, which showed that the material was a wide-bandgap semiconductor with bandgap of 4.7 eV at room temperature. The sample showed poor transmittance in the ultraviolet region but maximum transmission in the visible/near-infrared regions. The photoluminescence spectra recorded at different temperatures showed intense emission in the green region. The particle size estimated from transmission electron microscopy was 23 nm. The feasibility of CaWO4 for LTCC applications was studied from its sintering behavior. The sample was sintered at a relatively low temperature of 810°C to high density, without using any sintering aid. The surface morphology of the sintered sample was analyzed by scanning electron microscopy. The dielectric constant and loss factor of the sample measured at 5 MHz were found to be 10.50 and 1.56 × 10-3 at room temperature. The temperature coefficient of the dielectric constant was -88.71 ppm/°C. The experimental results obtained in this work demonstrate the potential of nano-CaWO4 as a low-temperature co-fired ceramic as well as an excellent luminescent material.

Broad Frequency LTCC Vertical Interconnect Transition for Multichip Modules and System on Package Applications

Science.gov (United States)

Decrossas, Emmanuel; Glover, Michael D.; Porter, Kaoru; Cannon, Tom; Mantooth, H. Alan; Hamilton, M. C.

2013-01-01

Various stripline structures and flip chip interconnect designs for high-speed digital communication systems implemented in low temperature co-fired ceramic (LTCC) substrates are studied in this paper. Specifically, two different transition designs from edge launch 2.4 millimeter connectors to stripline transmission lines embedded in LTCC are discussed. After characterizing the DuPont (sup trademark) 9K7 green tape, different designs are proposed to improve signal integrity for high-speed digital data. The full-wave simulations and experimental data validate the presented designs over a broad frequency band from Direct Current to 50 gigahertz and beyond.

Development of a micro-heat exchanger with stacked plates using LTCC technology

Directory of Open Access Journals (Sweden)

E. Vásquez-Alvarez

2010-09-01

Full Text Available A green ceramic tape micro-heat exchanger was developed using Low Temperature Co-fired Ceramics technology (LTCC. The device was designed by using Computational Aided Design software and simulations were made using a Computational Fluid Dynamics package (COMSOL Multiphysics to evaluate the homogeneity of fluid distribution in the microchannels. Four geometries were proposed and simulated in two and three dimensions to show that geometric details directly affect the distribution of velocity in the micro-heat exchanger channels. The simulation results were quite useful for the design of the microfluidic device. The micro-heat exchanger was then constructed using the LTCC technology and is composed of five thermal exchange plates in cross-flow arrangement and two connecting plates, with all plates stacked to form a device with external dimensions of 26 x 26 x 6 mm³.

Selective recovery of silver from waste low-temperature co-fired ceramic and valorization through silver nanoparticle synthesis.

Science.gov (United States)

Swain, Basudev; Shin, Dongyoon; Joo, So Yeong; Ahn, Nak Kyoon; Lee, Chan Gi; Yoon, Jin-Ho

2017-11-01

Considering the value of silver metal and silver nanoparticles, the waste generated during manufacturing of low temperature co-fired ceramic (LTCC) were recycled through the simple yet cost effective process by chemical-metallurgy. Followed by leaching optimization, silver was selectively recovered through precipitation. The precipitated silver chloride was valorized though silver nanoparticle synthesis by a simple one-pot greener synthesis route. Through leaching-precipitation optimization, quantitative selective recovery of silver chloride was achieved, followed by homogeneous pure silver nanoparticle about 100nm size were synthesized. The reported recycling process is a simple process, versatile, easy to implement, requires minimum facilities and no specialty chemicals, through which semiconductor manufacturing industry can treat the waste generated during manufacturing of LTCC and reutilize the valorized silver nanoparticles in manufacturing in a close loop process. Our reported process can address issues like; (i) waste disposal, as well as value-added silver recovery, (ii) brings back the material to production stream and address the circular economy, and (iii) can be part of lower the futuristic carbon economy and cradle-to-cradle technology management, simultaneously. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design of LTCC Based Fractal Antenna

KAUST Repository

AdbulGhaffar, Farhan

2010-09-01

The thesis presents a Sierpinski Carpet fractal antenna array designed at 24 GHz for automotive radar applications. Miniaturized, high performance and low cost antennas are required for this application. To meet these specifications a fractal array has been designed for the first time on Low Temperature Co-fired Ceramic (LTCC) based substrate. LTCC provides a suitable platform for the development of these antennas due to its properties of vertical stack up and embedded passives. The complete antenna concept involves integration of this fractal antenna array with a Fresnel lens antenna providing a total gain of 15dB which is appropriate for medium range radar applications. The thesis also presents a comparison between the designed fractal antenna and a conventional patch antenna outlining the advantages of fractal antenna over the later one. The fractal antenna has a bandwidth of 1.8 GHz which is 7.5% of the centre frequency (24GHz) as compared to 1.9% of the conventional patch antenna. Furthermore the fractal design exhibits a size reduction of 53% as compared to the patch antenna. In the end a sensitivity analysis is carried out for the fractal antenna design depicting the robustness of the proposed design against the typical LTCC fabrication tolerances.

Fabrications and Performance of Wireless LC Pressure Sensors through LTCC Technology.

Science.gov (United States)

Lin, Lin; Ma, Mingsheng; Zhang, Faqiang; Liu, Feng; Liu, Zhifu; Li, Yongxiang

2018-01-25

This paper presents a kind of passive wireless pressure sensor comprised of a planar spiral inductor and a cavity parallel plate capacitor fabricated through low-temperature co-fired ceramic (LTCC) technology. The LTCC material with a low Young's modulus of ~65 GPa prepared by our laboratory was used to obtain high sensitivity. A three-step lamination process was applied to construct a high quality cavity structure without using any sacrificial materials. The effects of the thickness of the sensing membranes on the sensitivity and detection range of the pressure sensors were investigated. The sensor with a 148 μm sensing membrane showed the highest sensitivity of 3.76 kHz/kPa, and the sensor with a 432 μm sensing membrane presented a high detection limit of 2660 kPa. The tunable sensitivity and detection limit of the wireless pressure sensors can meet the requirements of different scenes.

High density microelectronics package using low temperature cofirable ceramics

International Nuclear Information System (INIS)

Fu, S.-L.; Hsi, C.-S.; Chen, L.-S.; Lin, W. K.

1997-01-01

Low Temperature Cofired Ceramics (LTCC) is a relative new thick film process and has many engineering and manufacturing advantages over both the sequential thick film process and high temperature cofired ceramic modules. Because of low firing temperature, low sheet resistance metal conductors, commercial thick film resistors, and thick film capacitors can be buried in or printed on the substrates. A 3-D multilayer ceramic substrate can be prepared via laminating and co-firing process. The packing density of the LTCC substrates can be increased by this 3-D packing technology. At Kaohsiung Polytechnic Institute (KPI), a LTCC substrate system has been developed for high density packaging applications, which had buried surface capacitors and resistors. The developed cordierite-glass ceramic substrate, which has similar thermal expansion as silicon chip, is a promising material for microelectronic packaging. When the substrates were sintered at temperatures between 850-900 degree centigrade, a relative density higher than 96 % can be obtained. The substrate had a dielectric constant between 5.5 and 6.5. Ruthenium-based resistor pastes were used for resistors purposes. The resistors fabricated in/on the LTCC substrates were strongly depended on the microstructures developed in the resistor films. Surface resistors were laser trimmed in order to obtain specific values for the resistors. Material with composition Pb(Fe 2/3 W 1/3 ) x (Fe l/2 Nb l/2 ) y Ti 2 O 3 was used as dielectric material of the capacitor in the substrate. The material can be sintered at temperatures between 850-930 degree centigrade, and has dielectric constant as high as 26000. After cofiring, good adhesion between dielectric and substrate layers was obtained. Combing the buried resistors and capacitors together with the lamination of LTCC layer, a 3-dimensional multilayered ceramic package was fabricated. (author)

High density microelectronics package using low temperature cofirable ceramics

Energy Technology Data Exchange (ETDEWEB)

Fu, S -L; Hsi, C -S; Chen, L -S; Lin, W K [Kaoshiung Polytechnic Institute Ta-Hsu, Kaoshiung (China)

1998-12-31

Low Temperature Cofired Ceramics (LTCC) is a relative new thick film process and has many engineering and manufacturing advantages over both the sequential thick film process and high temperature cofired ceramic modules. Because of low firing temperature, low sheet resistance metal conductors, commercial thick film resistors, and thick film capacitors can be buried in or printed on the substrates. A 3-D multilayer ceramic substrate can be prepared via laminating and co-firing process. The packing density of the LTCC substrates can be increased by this 3-D packing technology. At Kaohsiung Polytechnic Institute (KPI), a LTCC substrate system has been developed for high density packaging applications, which had buried surface capacitors and resistors. The developed cordierite-glass ceramic substrate, which has similar thermal expansion as silicon chip, is a promising material for microelectronic packaging. When the substrates were sintered at temperatures between 850-900 degree centigrade, a relative density higher than 96 % can be obtained. The substrate had a dielectric constant between 5.5 and 6.5. Ruthenium-based resistor pastes were used for resistors purposes. The resistors fabricated in/on the LTCC substrates were strongly depended on the microstructures developed in the resistor films. Surface resistors were laser trimmed in order to obtain specific values for the resistors. Material with composition Pb(Fe{sub 2/3}W{sub 1/3}){sub x}(Fe{sub l/2}Nb{sub l/2}){sub y}Ti{sub 2}O{sub 3} was used as dielectric material of the capacitor in the substrate. The material can be sintered at temperatures between 850-930 degree centigrade, and has dielectric constant as high as 26000. After cofiring, good adhesion between dielectric and substrate layers was obtained. Combing the buried resistors and capacitors together with the lamination of LTCC layer, a 3-dimensional multilayered ceramic package was fabricated. (author)

Three-dimensional RF SoP technologies: LTCC versus LCP

KAUST Repository

Arabi, Eyad A.

2014-12-18

The system on package (SoP) is an emerging platform, introduced to provide enhanced functionality, and immense miniaturization through vertically integrated passive components in a multilayer process. This way the package is not a mere holder or cover but is a functional part of the system. The leading multilayer packaging technologies for SoP designs: low temperature co-fired ceramic (LTCC) and liquid crystal polymer (LCP) are compared in this work for the first time. Passive components and filters have been implemented in both technologies to show the advantages of the three-dimensional nature of these technologies. The comparison results show that parallel plate capacitors implemented in the ultra-thin LCP provides the highest capacitance density. For spiral inductors, conversely, LTCC inductors have the highest inductances while LCP inductors offer the highest self-resonant frequencies and the highest quality factors (Q). In a circuit level, simulated and measured results of a bandpass filter at 1.5 GHz show that both LCP and LTCC can provide similar performances with an incredible size reduction for the case of ultra-thin LCP. Also, the thin LCP filter exhibits a large degree of mechanical flexibility which makes this technology suitable for future flexible modules.

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.

Localized temperature stability in Low Temperature Cofired Ceramics (LTCC).

Energy Technology Data Exchange (ETDEWEB)

Dai, Steven Xunhu; Hsieh, Lung-Hwa.

2012-04-01

The base dielectrics of commercial low temperature cofired ceramics (LTCC) systems have a temperature coefficient of resonant frequency ({tau}{sub f}) in the range -50 {approx} -80 ppm/C. In this research we explored a method to realize zero or near zero {tau}{sub f} resonators by incorporating {tau}{sub f} compensating materials locally into a multilayer LTCC structure. To select composition for {tau}{sub f} adjustment, {tau}{sub f} compensating materials with different amount of titanates were formulated, synthesized, and characterized. Chemical interactions and physical compatibility between the {tau}{sub f} modifiers and the host LTCC dielectrics were investigated. Studies on stripline (SL) resonator panels with multiple compensating dielectrics revealed that: 1) compositions using SrTiO{sub 3} provide the largest {tau}{sub f} adjustment among titanates, 2) the {tau}{sub f} compensation is proportional to the amount of SrTiO{sub 3} in compensating materials, as well as the thickness of the compensating layer, and 3) the most effective {tau}{sub f} compensation is achieved when the compensating dielectric is integrated next to the SL. Using the effective dielectric constant of a heterogeneous layered dielectric structure, results from Method of Momentum (MoM) electromagnetic simulations are consistent with the experimental observations.

Integrated LTCC Pressure/Flow/Temperature Multisensor for Compressed Air Diagnostics†

Directory of Open Access Journals (Sweden)

Nicolas Craquelin

2010-12-01

Full Text Available We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues.

Integrated LTCC pressure/flow/temperature multisensor for compressed air diagnostics.

Science.gov (United States)

Fournier, Yannick; Maeder, Thomas; Boutinard-Rouelle, Grégoire; Barras, Aurélie; Craquelin, Nicolas; Ryser, Peter

2010-01-01

We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC) package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD) technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues.

Integrated LTCC Pressure/Flow/Temperature Multisensor for Compressed Air Diagnostics†

Science.gov (United States)

Fournier, Yannick; Maeder, Thomas; Boutinard-Rouelle, Grégoire; Barras, Aurélie; Craquelin, Nicolas; Ryser, Peter

2010-01-01

We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC) package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD) technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues. PMID:22163518

Substrate Integrated Waveguide Based Phase Shifter and Phased Array in a Ferrite Low Temperature Co-fired Ceramic Package

KAUST Repository

Nafe, Ahmed A.

2014-03-01

Phased array antennas, capable of controlling the direction of their radiated beam, are demanded by many conventional as well as modern systems. Applications such as automotive collision avoidance radar, inter-satellite communication links and future man-portable satellite communication on move services require reconfigurable beam systems with stress on mobility and cost effectiveness. Microwave phase shifters are key components of phased antenna arrays. A phase shifter is a device that controls the phase of the signal passing through it. Among the technologies used to realize this device, traditional ferrite waveguide phase shifters offer the best performance. However, they are bulky and difficult to integrate with other system components. Recently, ferrite material has been introduced in Low Temperature Co-fired Ceramic (LTCC) multilayer packaging technology. This enables the integration of ferrite based components with other microwave circuitry in a compact, light-weight and mass producible package. Additionally, the recent concept of Substrate Integrated Waveguide (SIW) allowed realization of synthesized rectangular waveguide-like structures in planar and multilayer substrates. These SIW structures have been shown to maintain the merits of conventional rectangular waveguides such as low loss and high power handling capabilities while being planar and easily integrable with other components. Implementing SIW structures inside a multilayer ferrite LTCC package enables monolithic integration of phase shifters and phased arrays representing a true System on Package (SoP) solution. It is the objective of this thesis to pursue realizing efficient integrated phase shifters and phased arrays combining the above mentioned technologies, namely Ferrite LTCC and SIW. In this work, a novel SIW phase shifter in ferrite LTCC package is designed, fabricated and tested. The device is able to operate reciprocally as well as non-reciprocally. Demonstrating a measured maximum

Realisation of microstrip junction circulator using LTCC technology

DEFF Research Database (Denmark)

Jensen, Thomas; Krozer, V; Kjærgaard, Claus

2011-01-01

An integrated circulator based on low-temperature cofired ceramics (LTCC) tapes and LTCC compatible ferrite tapes has been developed for the first time and its performance has been verified experimentally. The insertion loss is less than 2 dB and the isolation is better than 25 dB with a centre f...... frequency of 7.45 GHz. These results are in good agreement with simulations and offer a route towards integrated LTCC microwave circulators.......An integrated circulator based on low-temperature cofired ceramics (LTCC) tapes and LTCC compatible ferrite tapes has been developed for the first time and its performance has been verified experimentally. The insertion loss is less than 2 dB and the isolation is better than 25 dB with a centre...

Camber Evolution and Stress Development of Porous Ceramic Bilayers During Co-Firing

DEFF Research Database (Denmark)

Ni, De Wei; Esposito, Vincenzo; Schmidt, Cristine Grings

2013-01-01

sintering mismatch stress in co-fired CGO-LSM/CGO bilayer laminates was significantly lower than general sintering stresses expected for free sintering conditions. As a result, no co-firing defects were observed in the bilayer laminates, illustrating an acceptable sintering compatibility of the ceramic...

Continuous flow synthesis of nanoparticles using ceramic microfluidic devices

Energy Technology Data Exchange (ETDEWEB)

Gomez-de Pedro, S; Puyol, M; Alonso-Chamarro, J, E-mail: julian.alonso@uab.es [Grup de Sensors i Biosensors, Departament de Quimica, Facultat de Ciencies, Edifici Cn, Universitat Autonoma de Barcelona, Bellaterra 08193 (Spain)

2010-10-15

A microfluidic system based on the low-temperature co-fired ceramics technology (LTCC) is proposed to reproducibly carry out a simple one-phase synthesis and functionalization of monodispersed gold nanoparticles. It takes advantage of the LTCC technology, offering a fast prototyping without the need to use sophisticated facilities, reducing significantly the cost and production time of microfluidic systems. Some other interesting advantages of the ceramic materials compared to glass, silicon or polymers are their versatility and chemical resistivity. The technology enables the construction of multilayered systems, which can integrate other mechanical, electronic and fluidic components in a single substrate. This approach allows rapid, easy, low cost and automated synthesis of the gold colloidal, thus it becomes a useful approach in the progression from laboratory scale to pilot-line scale processes, which is currently demanded.

24-GHz LTCC Fractal Antenna Array SoP With Integrated Fresnel Lens

KAUST Repository

Ghaffar, Farhan A.

2012-09-30

A novel 24-GHz mixed low-temperature co-fired ceramic (LTCC) tape based system-on-package (SoP) is presented, which incorporates a fractal antenna array with an integrated grooved Fresnel lens. The four-element fractal array employs a relatively low dielectric constant substrate (CT707, εr = 6.4), whereas the lens has been realized on a high-dielectric-constant superstrate (CT765, εr = 68.7 ). The two (substrate and superstrate) are integrated through four corner posts to realize the required air gap (focal distance). The fractal array alone provides a measured gain of 8.9 dBi. Simulations predict that integration of this array with the lens increases the gain by 6 dB. Measurements reveal that the design is susceptible to LTCC fabrication tolerances. In addition to high gain, the SoP provides a bandwidth of 8%. The high performance and compact size (24 × 24 × 4.8 mm3 ) of the design makes it highly suitable for emerging wireless applications such as automotive radar front end.

Thick-Film and LTCC Passive Components for High-Temperature Electronics

Directory of Open Access Journals (Sweden)

A. Dziedzic

2013-04-01

Full Text Available At this very moment an increasing interest in the field of high-temperature electronics is observed. This is a result of development in the area of wide-band semiconductors’ engineering but this also generates needs for passives with appropriate characteristics. This paper presents fabrication as well as electrical and stability properties of passive components (resistors, capacitors, inductors made in thick-film or Low-Temperature Co-fired Ceramics (LTCC technologies fulfilling demands of high-temperature electronics. Passives with standard dimensions usually are prepared by screen-printing whereas combination of standard screen-printing with photolithography or laser shaping are recommenced for fabrication of micropassives. Attainment of proper characteristics versus temperature as well as satisfactory long-term high-temperature stability of micropassives is more difficult than for structures with typical dimensions for thick-film and LTCC technologies because of increase of interfacial processes’ importance. However it is shown that proper selection of thick-film inks together with proper deposition method permit to prepare thick-film micropassives (microresistors, air-cored microinductors and interdigital microcapacitors suitable for the temperature range between 150°C and 400°C.

LTCC magnetic components for high density power converter

Science.gov (United States)

Lebourgeois, Richard; Labouré, Eric; Lembeye, Yves; Ferrieux, Jean-Paul

2018-04-01

This paper deals with multilayer magnetic components for power electronics application and specifically for high frequency switching. New formulations based on nickel-zinc-copper spinel ferrites were developed for high power and high frequency applications. These ferrites can be sintered at low temperature (around 900°C) which makes them compatible with the LTCC (Low Temperature Co-fired Ceramics) technology. Metallic parts of silver or gold can be fully integrated inside the ferrite while guaranteeing the integrity of both the ferrite and the metal. To make inductors or transformers with the required properties, it is mandatory to have nonmagnetic parts between the turns of the winding. Then it is essential to find a dielectric material, which can be co-sintered both with the ferrite and the metal. We will present the solution we found to this problem and we will describe the results we obtained for a multilayer co-sintered transformer. We will see that these new components have good performance compared with the state of the art and are very promising for developing high density switching mode power supplies.

SIW based multilayer transition and power divider in LTCC technology

KAUST Repository

Abuzaid, Hattan

2013-06-01

A multilayer transition and balanced power divider are presented for millimeter-wave system-on-package (SoP). These two components operate at Ka-band and exploit the substrate integrate waveguide (SIW) technology with its shielding characteristics and the Low-temperature co-fired ceramics (LTCC) technology for its high density integration. A coupling slot has been used to perform vertical integration, which can be easily optimized through its length. The measured input return loss within the bandwidth of interest (32 GHz-38 GHz) is less than -15 dB and -18 dB for the multilayer transition and the power divider, respectively. The lateral dimensions of a multilayer system, such as a feed network of an array, can be greatly reduced by employing these 3D slot-coupled components. © 2013 IEEE.

About LTCC materials in the substance system of CaO-La{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}; Ueber LTCC-Werkstoffe aus dem Stoffsystem CaO-La{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Gemeinert, Marion

2009-09-01

Glass ceramic composites made of glassy and crystalline powders offer numerous possibilities for modifying materials properties e.g. sintering behaviour, thermal expansion coefficient, mechanical behaviour, chemical durability, dielectric properties and surface quality for special use. Glass ceramic composite powders can be used for the production of ceramic green tapes which are processed by LTCC (Low Temperature Co-fired Ceramics)- technology to form ceramic multilayers for electronic packaging in microsystems. During free sintering of LTCC-multilayers a lateral shrinkage occurs which is connected with a comparatively high shrinkage tolerance. Different sintering technologies are used to avoid the lateral shrinkage. A new possibility to achieve a zero lateral shrinkage is given by use of a self-constrained laminate. Therefore a multilayer is produced of two different materials for inner and outer layers, showing different sintering temperatures ({delta}T>50 K). Object of this dissertation was the development of LTCC-materials, which can be used for inner layers of a self-constrained laminate to reduce the lateral shrinkage nearly to zero. Therefore LTCC-materials in the field of CaO-La{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}, which can be sintered below 800 C, were investigated. Starting from the development of adapted glasses based on calcium lanthanium borate- and calcium lanthanium alumoborate glasses glass ceramic composites were produced by the addition of corundum powder. The composites crystallize during the sintering process almost completely. Lanthanum borate crystallizes from the glassy phase and calcium alumoborate and calcium alumoborate oxide respectively is formed by a chemical solid state reaction of the residual glassy phase, which is enriched by calcium borate, and the corundum. The proportional relation of the new crystalline phases determines the thermal and dielectric properties of the material. The most important formed new

5GHz LTCC-based aperture coupled wireless transmitter for system-on-package applications

KAUST Repository

Shamim, Atif

2012-01-01

A novel System-on-Package (SoP) implementation is presented for a transmitter (TX) module which makes use of electromagnetic coupling between the TX chip and the package antenna. The TX chip is realized in 0.13μm CMOS process and comprises an on-chip antenna, which serves as the oscillator\\'s inductor as well. The TX chip is housed in a Low Temperature Co-fired Ceramic (LTCC) package with a patch antenna. The on-chip antenna feeds the LTCC patch antenna through aperture coupling, thus negating the need for RF buffer amplifiers, matching elements, baluns, bond wires and package transmission lines. This is the first ever demonstration of wireless-interconnect between on-chip and package antennas which increases the gain and range of the TX module manyfold with respect to the on-chip antenna alone. Though the range of the TX SoP increases considerably, power consumption remains the same as that of the TX chip only. A simple analytical model for the new wireless-interconnect has been developed which helps determine the optimum position of the chip with respect to the aperture in the ground plane.

5GHz LTCC-based aperture coupled wireless transmitter for system-on-package applications

KAUST Repository

Shamim, Atif; Arsalan, Muhammad; Hojjat, Nasrin; Roy, Langis

2012-01-01

A novel System-on-Package (SoP) implementation is presented for a transmitter (TX) module which makes use of electromagnetic coupling between the TX chip and the package antenna. The TX chip is realized in 0.13μm CMOS process and comprises an on-chip antenna, which serves as the oscillator's inductor as well. The TX chip is housed in a Low Temperature Co-fired Ceramic (LTCC) package with a patch antenna. The on-chip antenna feeds the LTCC patch antenna through aperture coupling, thus negating the need for RF buffer amplifiers, matching elements, baluns, bond wires and package transmission lines. This is the first ever demonstration of wireless-interconnect between on-chip and package antennas which increases the gain and range of the TX module manyfold with respect to the on-chip antenna alone. Though the range of the TX SoP increases considerably, power consumption remains the same as that of the TX chip only. A simple analytical model for the new wireless-interconnect has been developed which helps determine the optimum position of the chip with respect to the aperture in the ground plane.

Robustness and Versatility of Thin Films on Low Temperature Cofired Ceramic (LTCC)

Energy Technology Data Exchange (ETDEWEB)

Wolf, J. Ambrose; Vianco, P. T.; Johnson, M. H.; Goldammer, S.

2011-10-09

Thin film multilayers have previously been introduced on multilayer low temperature cofired ceramic (LTCC). The ruggedness of a multipurpose Ti-Cu-Pt-Au stack has continued to benefit fabrication and reliability in state-of-theart modules. Space optimization is described, preserving miniaturization of critical spaces and component pads. Additional soldering details are also presented, including trends with solder-stop materials. Feature compensation becomes a simple step in the normal manufacturing flow which enables exact targeting of desired feature sizes. In addition, fine details of the manufacturing process, including ion milling, will be discussed. We will discuss full long-term aging results and structural details that reinforce the reliability and function. Different thin film materials for specific applications can be exploited for additional capabilities such as filters and other integral components. Cross sections verify the results shown. This successful integration of thin films on LTCC points to higher frequencies which require finer lines and spaces. Advancements of these applications become possible due to the associated progression of smaller skin depth and thinner metallic material.

Characterization of LC sensor structures realized by PCB and LTCC technology for determining moisture in building materials

Directory of Open Access Journals (Sweden)

Milan R. Radovanović

2018-03-01

Full Text Available This paper compares performances of two wireless sensors for measuring water concentration in building materials, one manufactured by the printed circuit board (PCB technology and another one using the low temperature co-fired ceramics (LTCC process. The fabricated sensors consist of inductive part (L and interdigitated capacitive part (C in one metal layer, connected in parallel. Inductance of inductive part was kept constant, whereas capacitance of capacitive part was changed by exposing the sensor to different moisture concentration, changing its resonant frequency. The variation of resonant frequency as a function of different water concentration was measured, using antenna coil and impedance analyser, in two widely used construction materials: clay brick and autoclaved aerated concrete block. Surface analysis for two sensors was performed by means of 3D profilometer. Mechanical properties of the sensors were measured for both conductive segments (copper and silver and substrates materials (PCB and ceramics substrates using nanoindenter. Comparative characteristics of the sensors are presented from their application point of view.

New Generation of LTCC Materials

Directory of Open Access Journals (Sweden)

Valant, Matjaz

2004-06-01

Full Text Available To reduce the complexity of LTCC systems and so accelerate the development of LTCC tapes with new functionalities it is necessary to reduce the number of phases within a particular tape. This can best be done by using glass-free single-phase ceramic systems. Such a material system consisting of low- and high-permittivity LTCC materials was developed based on Bi eulytite (permittivity; k’=16 and sillenite (k’=40 compounds and the δ-Bi2O3 solid solution with Nb2O5 (k’=90. The Ge and Si analogues of the sillenites and eulytites, and the 0.75Bi2O3⋅0.25Nb2O5 solid solution meet the main requirements for LTCC with respect to their sintering behavior (Ts=850-900oC, their mutual chemical compatibility, their compatibility with a silver electrode as well as their dielectric properties.

Para reducer la complejidad de los sistemas LTCC y así acelerar el desarrollo de láminas de LTCC con nuevas funcionalidades es necesario reducir el número de fases dentro de una determinada lámina. La mejor manera de hacer esto es usar sistemas cerámicos monofásicos libres de fase vítrea. Dicho sistema que consiste en materiales LTCC de baja- y alta-permitividad se ha desarrollado en base a compuestos de Bieulitita (permitividad; k’=16 y silenita (k’=40 y la solución sólida de δ-Bi2O3 con Nb2O5 (k’=90. Los análogos de Ge y Si de las silenitas y eulititas, y la solución sólida 0.75Bi2O3⋅0.25Nb2O5 cumplen los principales requerimientos de los LTCC respecto a su comportamiento de sinterización (Ts=850-900oC, su compatibilidad química mutua y su compatibilidad con electrodos de plata, así como en lo concerniente a sus propiedades dieléctricas.

The effect of self-heating on the performance of a tunable filter with embedded windings in a ferrite LTCC package

KAUST Repository

Arabi, Eyad A.; Shamim, Atif

2015-01-01

Traditionally, ferrite-based tunable filters are biased by large and bulky electromagnets, which require high currents to overcome the dissipated fields at the air interface between the electromagnet and the ferrite substrate. This problem has been solved by implementing the windings inside the package using ferrite low-temperature co-fired ceramic (LTCC). However, these embedded windings, which are densely packed, generate heat that affects the characteristics of the ferrite material. In this paper, we investigated the heat effects due to embedded windings in ferrite LTCC filters. We also incorporated the heating effects into an electromagnetic simulation model and achieved a good agreement between the simulations and the measurements. We found that increasing the temperature of the filter module from 0 °C to 190 °C by external heating causes the center frequency of the filter to shift by about 1 GHz. Alternatively, when a dc current is passed through the bias windings, heat is generated in the windings to a temperature of 250 °C measured at 260 mA of current. This heat causes the tunability of the filter to increase by more than 2%. © 2015 IEEE.

The effect of self-heating on the performance of a tunable filter with embedded windings in a ferrite LTCC package

KAUST Repository

Arabi, Eyad A.

2015-03-01

Traditionally, ferrite-based tunable filters are biased by large and bulky electromagnets, which require high currents to overcome the dissipated fields at the air interface between the electromagnet and the ferrite substrate. This problem has been solved by implementing the windings inside the package using ferrite low-temperature co-fired ceramic (LTCC). However, these embedded windings, which are densely packed, generate heat that affects the characteristics of the ferrite material. In this paper, we investigated the heat effects due to embedded windings in ferrite LTCC filters. We also incorporated the heating effects into an electromagnetic simulation model and achieved a good agreement between the simulations and the measurements. We found that increasing the temperature of the filter module from 0 °C to 190 °C by external heating causes the center frequency of the filter to shift by about 1 GHz. Alternatively, when a dc current is passed through the bias windings, heat is generated in the windings to a temperature of 250 °C measured at 260 mA of current. This heat causes the tunability of the filter to increase by more than 2%. © 2015 IEEE.

Sensors and packages based on LTCC and thick-film technology for ...

Indian Academy of Sciences (India)

Reliable operation in harsh environments such as high temperatures, high pressures, aggressive media and space, poses special requirements for sensors and packages, which usually cannot be met using polymer-based technologies. Ceramic technologies, especially LTCC (Low-Temperature Cofired Ceramic), offer a ...

Calorimetric sensitivity and thermal resolution of a novel miniaturized ceramic DSC chip in LTCC technology

Energy Technology Data Exchange (ETDEWEB)

Missal, Wjatscheslaw, E-mail: wmissal@gmx.net [Department of Functional Materials, University of Bayreuth, 95440 Bayreuth (Germany); Kita, Jaroslaw [Department of Functional Materials, University of Bayreuth, 95440 Bayreuth (Germany); Wappler, Eberhard [wsk Mess- und Datentechnik GmbH, Gueterbahnhofstr. 1, 63450 Hanau (Germany); Bechtold, Franz [VIA electronic GmbH, Robert-Friese-Str. 3, 07629 Hermsdorf (Germany); Moos, Ralf [Department of Functional Materials, University of Bayreuth, 95440 Bayreuth (Germany)

2012-09-10

Highlights: Black-Right-Pointing-Pointer Unique vertical design of a DSC device manufactured in the low-cost LTCC technology and therefore capable of one-way use. Black-Right-Pointing-Pointer Fully functional DSC device with a size of only 1.5 mm Multiplication-Sign 11 mm Multiplication-Sign 39 mm enabling very low power consumption. Black-Right-Pointing-Pointer Comparable measurement performance as conventional DSC whilst also suitable for mobile thermal analysis. Black-Right-Pointing-Pointer Thermal resolution is 0.12 (TAWN test). Repeatability of the peak area is within 0.3% for indium samples. Black-Right-Pointing-Pointer Calorimetric sensitivity: linear with regard to temperature and independent from sample mass and heating rate in wide ranges. - Abstract: The calorimetric properties of a novel miniaturized ceramic differential scanning calorimeter device (MC-DSC) with integrated heater and crucible are presented. All features of a conventional DSC apparatus (including oven) are integrated into this DSC device of the size 11 mm Multiplication-Sign 39 mm Multiplication-Sign 1.5 mm. The MC-DSC device is suitable for one-way use, since it is fully manufactured in the low-cost planar low temperature co-fired ceramics technology. First characterization of this device is performed using indium, tin and zinc samples. The calorimetric sensitivity at 156.6 Degree-Sign C is 0.24 J/ Degree-Sign C s. It depends linearly on temperature in the range of at least 150 Degree-Sign C and 420 Degree-Sign C. The calorimetric sensitivity is constant up to an enthalpy of fusion of at least {Delta}H = 750 mJ (at 156.6 Degree-Sign C). The thermal analysis of indium in direct contact to the crucible of the chip even reveals a constant calorimetric sensitivity up to an enthalpy of fusion of at least {Delta}H = 1000 mJ. The repeatability of the peak area is within {+-}0.3% (11 mg indium, 10 measurements). The thermal resolution determined using 4,4 Prime -azoxyanisole under TAWN test

Micromecanizado mediante láseres de femtosegundos de cerámicas LTCC. Fabricación de microcalentadores para un sensor de monóxido de carbono

Directory of Open Access Journals (Sweden)

Gómez, David

2007-08-01

Full Text Available In present work, the processability of LTCC (Low Temperature Co-fired Ceramics by means of femtosecond laser ablation is shown. This kind of material, with a clear technological interest in the development of microsensors, possesses a high mechanical fragility in the sintered state and, consequently, contact methods for micromaching (micromilling, microgrinding, etc. lead to fracture or the appearance of microcracks. The paper has been structured in two different parts. Firstly, a detailed study of the process has been performed, obtaining the fundamental parameters, as ablation threshold and incubation factor and a parametrization of width and height of microchannels as a function of fluence and feedrate. Afterwards, these results have allowed the fabrication of simple structures as boxes, passing-through holes and 21/2D structures. Finally, the technological interest of the material and the process is shown. This way, microheaters in LTCC have been fabricated as initial stage of a carbon monoxide chemoresistive sensor. The system allows the heating of a 1mm x 1mm area up to 490ºC with almost no heat dissipation to the surrounding area.

El presente trabajo pretende mostrar la procesabilidad de cerámicas de baja temperatura de sinterizado, LTCC (Low Temperature Co-fired Ceramics mediante ablación láser con pulsos ultracortos (femtosegundos. Este tipo de material, de indudable interés tecnológico en el desarrollo de microsensores, presenta una alta fragilidad en el estado sinterizado, por lo que la utilización de métodos de contacto (fresado, torneado, etc. para su mecanizado conduce a la fractura o la aparición de microgrietas y desconchamientos. El trabajo ha sido dividido en dos partes bien diferenciadas. Primeramente, se ha realizado un estudio del proceso, obteniéndose los parámetros fundamentales (el umbral de ablación y el coeficiente de incubación y se ha procedido a una parametrización de la anchura y altura de

Dual-band LTCC antenna based on 0.95Zn2SiO4-0.05CaTiO3 ceramics for GPS/UMTS applications

Science.gov (United States)

Dou, Gang; Li, Yu-Xia; Guo, Mei

2015-10-01

In this paper, we present a compact low-temperature co-fired ceramic (LTCC) dual-band antenna by using the electromagnetic coupling effect concept for global positioning system (GPS) and universal mobile telecommunication system (UMTS) applications. The overall dimension of the antenna is 8.6 mm × 13.0 mm × 1.1 mm. It consists of double meander lines and a via hole line. The top meander line operates at the upper band, and the bottom radiating patch is designed for the lower band. The via-hole line is employed to connect the double meander lines. Because of the effect of the coupled line, total dimension of the proposed antenna is greatly reduced. With the 2.5: voltage standing wave ratio (VSWR) impedance bandwidth definition, the lower and upper bands have the bandwidths of 110 MHz and 150 MHz, respectively. The proposed antenna is successfully designed, simulated, and analyzed by a high frequency structure simulator (HFSS). And the antenna is manufactured by using the 0.95Zn2SiO4-0.05CaTiO3 ceramics (εr = 7.1, tanδ = 0.00038) that is prepared by ourselves. The results show that the antenna is compact, efficient, and of near omnidirectional radiation pattern. Project supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20133718120009), the Natural Science Foundation of Shandong Provence, China (Grant Nos. ZR2013FQ002 and ZR2014FQ006), the China Postdoctoral Science Foundation (Grant No. 2014M551935), the Qingdao Municipality Postdoctoral Science Foundation, China, and the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents, China (Grant Nos. 2013RCJJ042 and 2014RCJJ052).

Low-Temperature Sintering Li3Mg1.8Ca0.2NbO6 Microwave Dielectric Ceramics with LMZBS Glass

Science.gov (United States)

Wang, Gang; Zhang, Huaiwu; Liu, Cheng; Su, Hua; Jia, Lijun; Li, Jie; Huang, Xin; Gan, Gongwen

2018-05-01

Li3Mg1.8Ca0.2NbO6 ceramics doped with Li2O-MgO-ZnO-B2O3-SiO2 glass (LMZBS) were prepared via a solid-state route. The LMZBS glass effectively reduced the sintering temperature of Li3Mg1.8Ca0.2NbO6 ceramics to 950°C. The effects of the LMZBS glass on the sintering behavior, microstructures and microwave dielectric properties of Li3Mg1.8Ca0.2NbO6 ceramics are discussed in detail. Among all the LMZBS doped Li3Mg1.8Ca0.2NbO6 ceramics, the sample with 1 wt.% of LMZBS glass sintered at 950°C for 4 h exhibited good dielectric properties: ɛ r = 16.7, Q × f = 31,000 GHz (9.92 GHz), τ f = - 1.3 ppm/°C. The Li3Mg1.8Ca0.2NbO6 ceramics possessed excellent chemical compatibility with Ag electrodes, and could be applied in low temperature co-fired ceramics (LTCC) applications.

An LTCC Based Compact SIW Antenna Array Feed Network for a Passive Imaging Radiometer

KAUST Repository

Abuzaid, Hattan

2013-02-05

Passive millimeter-wave (PMMW) imaging is a technique that allows the detection of inherent millimeter-wave radiation emitted by bodies. Since different bodies with varying properties emit unequal power intensities, a contrast can be established to detect their presence. The advantage of this imaging scheme over other techniques, such as optical and infrared imaging, is its ability to operate under all weather conditions. This is because the relatively long wavelengths of millimeter-waves, as compared to visible light, penetrate through clouds, fog, and sandstorms. The core of a PMMW camera is an antenna, which receives the electromagnetic radiation from a scene. Because PMMW systems require high gains to operate, large antenna arrays are typically employed. This mandatory increase of antenna elements is associated with a large feeding network. Therefore, PMMW cameras usually have a big profile. In this work, two enabling technologies, namely, Substrate integrated Waveguide (SIW) and Low Temperature Co-fired Ceramic (LTCC), are coupled with an innovative design to miniaturize the passive front-end. The two technologies synergize very well with the shielded characteristics of SIW and the high density multilayer integration of LTCC. The proposed design involves a novel multilayer power divider, which is incorporated in a folded feed network structure by moving between layers. The end result is an efficient feeding network, which footprint is least affected by an increase in array size. This is because the addition of more elements is accommodated by a vertical expansion rather than a lateral one. To characterize the feed network, an antenna array has been designed and integrated through efficient transitions.The complete structure has been simulated and fabricated. The results demonstrate an excellent performance, manifesting in a gain of 20 dBi and a bandwidth of more than 11.4% at 35 GHz. These values satisfy the general requirements of a PMMW system.

Scaling up the microwave firing of ceramics

International Nuclear Information System (INIS)

Wroe, F.C.R.

1993-01-01

EA Technology, through a comprehensive R ampersand D program, is developing new microwave furnace technology focused on the ceramics processing industries. Using a combination of computer modelling, experimentation and feasibility studies, EA Technology has developed processes and procedures for firing large ceramic components. The aim of this work is to describe the investigation of the firing of ceramic products such as bricks, pottery, refractories, and industrial ceramics, using advanced processing techniques to produce and maintain uniformity of temperature throughout the components and kiln environment. This has achieved the goal of producing uniform microstructures and low thermal stress by careful control of the firing cycle. This paper illustrates the feasibility of microwave-assisted firing and shows it to be economically viable in terms of energy costs and process control. 6 refs., 1 fig

Effect of repeated ceramic firings on the marginal and internal adaptation of metal-ceramic restorations fabricated with different CAD-CAM technologies.

Science.gov (United States)

Kocaağaoğlu, Hasan; Albayrak, Haydar; Kilinc, Halil Ibrahim; Gümüs, Hasan Önder

2017-11-01

The use of computer-aided design and computer-aided manufacturing (CAD-CAM) for metal-ceramic restorations has increased with advances in the technology. However, little is known about the marginal and internal adaptation of restorations fabricated using laser sintering (LS) and soft milling (SM). Moreover, the effects of repeated ceramic firings on the marginal and internal adaptation of metal-ceramic restorations fabricated with LS and SM is also unknown. The purpose of this in vitro study was to investigate the effects of repeated ceramic firings on the marginal and internal adaptation of metal-ceramic copings fabricated using the lost wax (LW), LS, and SM techniques. Ten LW, 10 LS, and 10 SM cobalt-chromium (Co-Cr) copings were fabricated for an artificial tooth (Frasaco GmbH). After the application of veneering ceramic (VITA VMK Master; VITA Zahnfabrik), the marginal and internal discrepancies of these copings were measured with a silicone indicator paste and a stereomicroscope at ×100 magnification after the first, second, and third clinical simulated ceramic firing cycles. Repeated measures 2-way ANOVA and the Fisher LSD post hoc test were used to evaluate differences in marginal and internal discrepancies (α=.05). Neither fabrication protocol nor repeated ceramic firings had any statistically significant effect on internal discrepancy values (P>.05). Marginal discrepancy values were also statistically unaffected by repeated ceramic firings (P>.05); however, the fabrication protocol had a significant effect on marginal discrepancy values (Pmarginal discrepancy values than LS or SM (PMarginal discrepancy values did not vary between LS and SM (P>.05). All groups demonstrated clinically acceptable marginal adaptation after repeated ceramic firing cycles; however, the LS and SM groups demonstrated better marginal adaptation than that of LW group and may be appropriate clinical alternatives to LW. Copyright © 2017 Editorial Council for the Journal of

Novel LTCC-potentiometric microfluidic device for biparametric analysis of organic compounds carrying plastic antibodies as ionophores: application to sulfamethoxazole and trimethoprim.

Science.gov (United States)

Almeida, S A A; Arasa, E; Puyol, M; Martinez-Cisneros, C S; Alonso-Chamarro, J; Montenegro, M C B S M; Sales, M G F

2011-12-15

Monitoring organic environmental contaminants is of crucial importance to ensure public health. This requires simple, portable and robust devices to carry out on-site analysis. For this purpose, a low-temperature co-fired ceramics (LTCC) microfluidic potentiometric device (LTCC/μPOT) was developed for the first time for an organic compound: sulfamethoxazole (SMX). Sensory materials relied on newly designed plastic antibodies. Sol-gel, self-assembling monolayer and molecular-imprinting techniques were merged for this purpose. Silica beads were amine-modified and linked to SMX via glutaraldehyde modification. Condensation polymerization was conducted around SMX to fill the vacant spaces. SMX was removed after, leaving behind imprinted sites of complementary shape. The obtained particles were used as ionophores in plasticized PVC membranes. The most suitable membrane composition was selected in steady-state assays. Its suitability to flow analysis was verified in flow-injection studies with regular tubular electrodes. The LTCC/μPOT device integrated a bidimensional mixer, an embedded reference electrode based on Ag/AgCl and an Ag-based contact screen-printed under a micromachined cavity of 600 μm depth. The sensing membranes were deposited over this contact and acted as indicating electrodes. Under optimum conditions, the SMX sensor displayed slopes of about -58.7 mV/decade in a range from 12.7 to 250 μg/mL, providing a detection limit of 3.85 μg/mL and a sampling throughput of 36 samples/h with a reagent consumption of 3.3 mL per sample. The system was adjusted later to multiple analyte detection by including a second potentiometric cell on the LTCC/μPOT device. No additional reference electrode was required. This concept was applied to Trimethoprim (TMP), always administered concomitantly with sulphonamide drugs, and tested in fish-farming waters. The biparametric microanalyzer displayed Nernstian behaviour, with average slopes -54.7 (SMX) and +57.8 (TMP) m

Solid state reaction in alumina nanoparticles/LZSA glass-ceramic composites

International Nuclear Information System (INIS)

Montedo, O.K.; Oliveira, A.N. de; Raupp-Pereira, F.

2016-01-01

Full text: The aim of this work is to present results related to solid state reactions on LZSA glass-ceramic composites containing alumina reinforcement nano-particles. A LZSA (Li2O-ZrO2-SiO2-Al2O3) glass-ceramic has been prepared by sintering of powders and characterized. Composites containing 0 to 77 vol.% of alumina nanoparticles (27-43 nm APS, 35 m2.g-1 SSA) and a 16.9Li2O•5.0ZrO2•65.1SiO2•8.6Al2O3 glass-ceramic matrix have been prepared. X-ray diffractometry studies have been performed in order of investigating the solid state reactions occurring in LZSA-based composites. Results of the XRD patterns have been related to the coefficient of thermal expansion (CTE), Young modulus, and dielectric constant, showing that, in comparison with the glass-ceramic composition, the composites showed a decrease of CTE with the alumina concentration increasing, due to the increasing of beta-spodumeness formation (solid solution of beta-spodumene, Li2O.Al2O3.4-10SiO2). The performance of the glass-ceramic was improved with the alumina nano-particles addition, showing potential of using in the preparation of Low Thermal Co-fired Ceramics (LTCC). (author)

Base Metal Co-Fired Multilayer Piezoelectrics

Directory of Open Access Journals (Sweden)

Lisheng Gao

2016-03-01

Full Text Available Piezoelectrics have been widely used in different kinds of applications, from the automobile industry to consumer electronics. The novel multilayer piezoelectrics, which are inspired by multilayer ceramic capacitors, not only minimize the size of the functional parts, but also maximize energy efficiency. Development of multilayer piezoelectric devices is at a significant crossroads on the way to achieving low costs, high efficiency, and excellent reliability. Concerning the costs of manufacturing multilayer piezoelectrics, the trend is to replace the costly noble metal internal electrodes with base metal materials. This paper discusses the materials development of metal co-firing and the progress of integrating current base metal chemistries. There are some significant considerations in metal co-firing multilayer piezoelectrics: retaining stoichiometry with volatile Pb and alkaline elements in ceramics, the selection of appropriate sintering agents to lower the sintering temperature with minimum impact on piezoelectric performance, and designing effective binder formulation for low pO2 burnout to prevent oxidation of Ni and Cu base metal.

Development of a ceramic tamper indicating seal: SRNL contributions

International Nuclear Information System (INIS)

Krementz, Dan; Brinkman, Kyle S.; Martinez-Rodriguez, Michael J.; Mendez-Torres, Adrian E.; Weeks, George E.

2013-01-01

Savannah River National Laboratory (SRNL) and Sandia National Laboratories (SNL) are collaborating on development of a Ceramic Seal, also sometimes designated the Intrinsically Tamper Indicating Ceramic Seal (ITICS), which is a tamper indicating seal for international safeguards applications. The Ceramic Seal is designed to be a replacement for metal loop seals that are currently used by the IAEA and other safeguards organizations. The Ceramic Seal has numerous features that enhance the security of the seal, including a frangible ceramic body, protective and tamper indicating coatings, an intrinsic unique identifier using Laser Surface Authentication, electronics incorporated into the seal that provide cryptographic seal authentication, and user-friendly seal wire capture. A second generation prototype of the seal is currently under development whose seal body is of Low Temperature Co-fired Ceramic (LTCC) construction. SRNL has developed the mechanical design of the seal in an iterative process incorporating comments from the SNL vulnerability review team. SRNL is developing fluorescent tamper indicating coatings, with recent development focusing on optimizing the durability of the coatings and working with a vendor to develop a method to apply coatings on a 3-D surface. SRNL performed a study on the effects of radiation on the electronics of the seal and possible radiation shielding techniques to minimize the effects. SRNL is also investigating implementation of Laser Surface Authentication (LSA) as a means of unique identification of each seal and the effects of the surface coatings on the LSA signature.

DEVELOPMENT OF A CERAMIC TAMPER INDICATING SEAL: SRNL CONTRIBUTIONS

Energy Technology Data Exchange (ETDEWEB)

Krementz, D.; Brinkman, K.; Martinez-Rodriguez, M.; Mendez-Torres, A.; Weeks, G.

2013-06-03

Savannah River National Laboratory (SRNL) and Sandia National Laboratories (SNL) are collaborating on development of a Ceramic Seal, also sometimes designated the Intrinsically Tamper Indicating Ceramic Seal (ITICS), which is a tamper indicating seal for international safeguards applications. The Ceramic Seal is designed to be a replacement for metal loop seals that are currently used by the IAEA and other safeguards organizations. The Ceramic Seal has numerous features that enhance the security of the seal, including a frangible ceramic body, protective and tamper indicating coatings, an intrinsic unique identifier using Laser Surface Authentication, electronics incorporated into the seal that provide cryptographic seal authentication, and user-friendly seal wire capture. A second generation prototype of the seal is currently under development whose seal body is of Low Temperature Co-fired Ceramic (LTCC) construction. SRNL has developed the mechanical design of the seal in an iterative process incorporating comments from the SNL vulnerability review team. SRNL is developing fluorescent tamper indicating coatings, with recent development focusing on optimizing the durability of the coatings and working with a vendor to develop a method to apply coatings on a 3-D surface. SRNL performed a study on the effects of radiation on the electronics of the seal and possible radiation shielding techniques to minimize the effects. SRNL is also investigating implementation of Laser Surface Authentication (LSA) as a means of unique identification of each seal and the effects of the surface coatings on the LSA signature.

Synthesis and characterisation of novel low temperature ceramic and its implementation as substrate in dual segment CDRA

Science.gov (United States)

Kumari, Preeti; Tripathi, Pankaj; Sahu, Bhagirath; Singh, S. P.; Parkash, Om; Kumar, Devendra

2018-02-01

Li2O-(2-3x)MgO-(x)Al2O3-P2O5 (LMAP) (x = 0.00-0.08) ceramic system was prepared through solid state synthesis route at different sintering temperatures (800-925 °C). A small addition of Al2O3 (x = 0.02) in LMAP ceramics lowers the sintering temperature by more than 100 °C with good relative density of 94.13%. The sintered samples were characterized in terms of density, apparent porosity, water absorption, crystal structure, micro-structure and microwave dielectric properties. Silver compatibility test is also performed for its use as electrode material in low temperature co-fired ceramic (LTCC) application. To check the performance of the prepared LTCC as substrate, a microstrip-fed aperture-coupled dual segment cylindrical dielectric resonator antenna (DS-CDRA) is designed using LMAP (x = 0.02) ceramic as substrate material and Barium Strontium Titanate with 10 wt% of PbO-BaO-B2O3-SiO2 glass (BSTG) and Teflon as the components of resonating material. The simulation study of the DS-CDRA is performed using the Ansys High Frequency Structure Simulator (HFSS) software. A conductive coating of silver is used on the substrate. The simulated and measured -10 dB reflection coefficient bandwidths of 910 MHz (9.07-9.98 GHz at resonant frequency of 9.49 GHz) and 1080 MHz (8.68-9.76 GHz at resonant frequency of 9.36 GHz), respectively are achieved. The measured results of the fabricated antenna are found in good agreement with the simulation results. The prepared material can find potential applications in radar and radio navigation as well as radio astronomy and military satellite communication.

Fabrication and performance evaluation of a high temperature co-fired ceramic vaporizing liquid microthruster

International Nuclear Information System (INIS)

Cheah, Kean How; Low, Kay-Soon

2015-01-01

This paper presents the study of a microelectromechanical system (MEMS)-scaled microthruster using ceramic as the structural material. A vaporizing liquid microthruster (VLM) has been fabricated using the high temperature co-fired ceramic (HTCC) technology. The developed microthruster consists of five components, i.e. inlet, injector, vaporizing chamber, micronozzle and microheater, all integrated in a chip with a dimension of 30 mm × 26 mm × 8 mm. In the dry test, the newly developed microheater which is deposited on zirconia substrate consumes 21% less electrical power than those deposited on silicon substrate to achieve a temperature of 100 °C. Heating temperature as high as 409.1 °C can be achieved using just 5 W of electrical power. For simplicity and safety, a functional test of the VLM with water as propellant has been conducted in the laboratory. Full vaporization of water propellant feeding at different flow rates has been successfully demonstrated. A maximum thrust of 633.5 µN at 1 µl s −1 propellant consumption rate was measured using a torsional thrust stand. (paper)

Study of the oxidation effects on isothermal solidification based high temperature stable Pt/In/Au and Pt/In/Ag thick film interconnections on LTCC substrate

International Nuclear Information System (INIS)

Kumar, Duguta Suresh; Khanna, P. K.; Suri, Nikhil; Sharma, R. P.

2016-01-01

The objective of the presented paper is to determine the oxidized phase compositions of indium lead-free solders during solidification at 190 ° C under room environment with the help of X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDX). Many lead-free solders alloys available oxidizes and have poor wetting properties. The oxidation of pure indium solder foil, Au, Pt, and Ag alloys were identified and investigated, in the process of isothermal solidification based solder joints construction at room environment and humidity. Both EDX and XRD characterization techniques were performed to trace out the amount of oxide levels and variety of oxide formations at solder interface respectively. The paper also aims to report the isothermal solidification technique to provide interconnections to pads on Low temperature co-fired ceramic (LTCC) substrate. It also elaborates advantages of isothermal solidification over the other methods of interconnection. Scanning electron microscope (SEM) used to identify the oxidized spots on the surface of Pt, Ag substrates and In solder. The identified oxides were reported.

Methods for characterization of wafer-level encapsulation applied on silicon to LTCC anodic bonding

International Nuclear Information System (INIS)

Khan, M F; Ghavanini, F A; Enoksson, P; Haasl, S; Löfgren, L; Persson, K; Rusu, C; Schjølberg-Henriksen, K

2010-01-01

This paper presents initial results on generic characterization methods for wafer-level encapsulation. The methods, developed specifically to evaluate anodic bonding of low-temperature cofired ceramics (LTCC) to Si, are generally applicable to wafer-level encapsulation. Different microelectromechanical system (MEMS) structures positioned over the whole wafer provide local information about the bond quality. The structures include (i) resonating cantilevers as pressure sensors for bond hermeticity, (ii) resonating bridges as stress sensors for measuring the stress induced by the bonding and (iii) frames/mesas for pull tests. These MEMS structures have been designed, fabricated and characterized indicating that local information can easily be obtained. Buried electrodes to enable localized bonding have been implemented and their effectiveness is indicated from first results of the novel Si to LTCC anodic bonding.

Development of LTCC Materials with High Mechanical Strength

International Nuclear Information System (INIS)

Kawai, Shinya; Nishiura, Sousuke; Terashi, Yoshitake; Furuse, Tatsuji

2011-01-01

We have developed LTCC materials suitable for substrates of RF modules used in mobile phone. LTCC can provide excellent solutions to requirements of RF modules, such as down-sizing, embedded elements and high performance. It is also important that LTCC material has high mechanical strength to reduce risk of fracture by mechanical impact. We have established a method of material design for high mechanical strength. There are two successive steps in the concept to achieve high mechanical strength. The first step is to improve mechanical strength by increasing the Young's modulus, and the second step is either further improvement through the Young's modulus or enhancement of the fracture energy. The developed material, so called high-strength LTCC, thus possesses mechanical strength of 400MPa, which is twice as strong as conventional material whose mechanical strength is approximately 200MPa in typical. As a result, high-strength LTCC shows an excellent mechanical reliability, against the drop impact test for example. The paper presents material design and properties of LTCC materials.

Design of the ITER high-frequency magnetic diagnostic coils

International Nuclear Information System (INIS)

Toussaint, M.; Testa, D.; Baluc, N.; Chavan, R.; Fournier, Y.; Lister, J.B.; Maeder, T.; Marmillod, P.; Sanchez, F.; Stoeck, M.

2011-01-01

This paper is an overview of work carried out on the design of the ITER high-frequency magnetic diagnostic coil (HF sensor). In the first part, the ITER requirements for the HF sensor are presented. In the second part, the ITER reference design of the HF sensor has been assessed and showed some potential weaknesses, which led us to the conclusion that alternative designs could usefully be examined. Several options have been explored, and are presented in the third part: (a) direct laser cutting a metallic tube, (b) stacking of plane windings manufactured from a tungsten plate by electrical discharge machining, (c) coil using the conventional spring manufacture. In the fourth part, sensors using the low temperature co-fired ceramic technology (LTCC) are presented: (d) monolithic 1D magnetic flux sensors based on LTCC technology, and (e) monolithic 3D magnetic flux sensors based on the same LTCC technology. The solution which showed the best results is the monolithic 3D magnetic flux sensor based on LTCC.

Effects of multiple firings on the microstructure of zirconia and veneering ceramics.

Science.gov (United States)

Alkurt, Murat; Yeşil Duymus, Zeynep; Gundogdu, Mustafa

2016-01-01

The aim of study was to evaluate the effects of multiple firings on the microstructures of zirconia and two ceramics. Vita VM9 (VMZ) and Cerabien ZR (C-Z) ceramics on a zirconia framework and zirconia without veneering ceramic (WO-Z) were evaluated. Firing methods included firing two, five, and ten times (n=10). The effects of multiple firings on the surface hardness of the materials were evaluated using a Vickers hardness (HV) tester. Data were analyzed by two-way ANOVA and Tukey's test (α=0.05). After firing five and ten times, the hardness of VM-Z and C-Z increased significantly (p0.05). In the XRD analysis, zirconia had similar tetragonal (t)-monoclinic (m) phase transformations of Y-TZP after the different firing times. Clinically, multiple firings did not affect the microstructure of zirconia, but the structures of the two ceramics were affected.

An Integrable SIW Phase Shifter in a Partially Magnetized Ferrite LTCC Package

KAUST Repository

Nafe, Ahmed; Shamim, Atif

2015-01-01

, yielding them unsuitable for this kind of application. In this paper, a novel compact light-weight substrate integrated waveguide (SIW) based phase shifter realized in a multi-layer ferrite low-temperature co-fired ceramic package with embedded bias

Effect of La-CO substitution on the crystal structure and magnetic properties of low temperature sintered Sr1-xLaxFe12-xCoxO19 (x=0-0.5) ferrites

Science.gov (United States)

Peng, Long; Li, Lezhong; Wang, Rui; Hu, Yun; Tu, Xiaoqiang; Zhong, Xiaoxi

2015-11-01

The La-Co substituted Sr1-xLaxFe12-xCoxO19 (x=0-0.5) ferrites with appropriate Bi2O3 additive were prepared at a low sintering temperature of 890 °C compatible with LTCC (low temperature co-fired ceramics) systems, and the effect of La-Co substitution on their crystal structure and magnetic properties was investigated. The results show that the pure M-type phase is successfully obtained when the La-Co substitution amount x does not exceed 0.3. However, the single M-type phase structure transforms to multiphase structure with further increased x, where the α-Fe2O3 phase and La2O3 phase coexist with the M-type phase. Moreover, the saturation magnetization Ms, magnetic anisotropy field Ha, intrinsic coercivity Hci, and Curie temperature TC of the ferrites depend on the La-Co substitution amount strongly, which are suggested to be determined by the partially substitution of La3+-Co2+ ions for Sr2+-Fe3+ ions with x not higher than 0.3. It is found that the obtained Sr1-xLaxFe12-xCoxO19 (x=0.2 and 0.3) ferrites can provide improved magnetic properties (Ms>62 emu/g, Ha>1400 kA/m, and Hci>320 kA/m) as low temperature sintered M-type hexaferrites for microwave LTCC applications.

Biomass co-firing

DEFF Research Database (Denmark)

Yin, Chungen

2013-01-01

Co-firing biomass with fossil fuels in existing power plants is an attractive option for significantly increasing renewable energy resource utilization and reducing CO2 emissions. This chapter mainly discusses three direct co-firing technologies: pulverized-fuel (PF) boilers, fluidized-bed combus......Co-firing biomass with fossil fuels in existing power plants is an attractive option for significantly increasing renewable energy resource utilization and reducing CO2 emissions. This chapter mainly discusses three direct co-firing technologies: pulverized-fuel (PF) boilers, fluidized......-bed combustion (FBC) systems, and grate-firing systems, which are employed in about 50%, 40% and 10% of all the co-firing plants, respectively. Their basic principles, process technologies, advantages, and limitations are presented, followed by a brief comparison of these technologies when applied to biomass co...

Influence of B2O3 content on sintering behaviour and dielectric properties of La2O3-B2O3-CaO/Al2O3 glass-ceramic composites for LTCC applications

Science.gov (United States)

Wang, F. L.; Zhang, Y. W.; Chen, X. Y.; Mao, H. J.; Zhang, W. J.

2018-01-01

La2O3-B2O3-CaO glasses with different B2O3 content were synthesized by melting method to produce glass/ceramic composites in this work. XRD and DSC results revealed that the diminution of B2O3 content was beneficial to increase the crystallization tendency of glass and improve the quality of crystalline phase, while decreasing the effect of glass during sintering process as sintering aids. The choice of glass/ceramic mass ratio was also influenced by the B2O3 content of glass. Dense samples sintered at 875 ºC showed good dielectric properties which meet the requirement of LTCC applications: moderate dielectric constant (7.8-9.4) and low dielectric loss (2.0×10-3).

Ageing of low-firing prehistoric ceramics in hydrothermal conditions

Directory of Open Access Journals (Sweden)

Petra Zemenová

2012-03-01

Full Text Available Remains of a prehistoric ceramic object, a moon-shaped idol from the Bronze Age found in archaeological site Zdiby near Prague in the Czech Republic, were studied especially in terms of the firing temperature. Archaeological ceramics was usually fired at temperatures below 1000 °C. It contained unstable non-crystalline products, residua after calcination of clay components of a ceramic material. These products as metakaolinite can undergo a reverse rehydration to a structure close to kaolinite. The aim of this work was to prove whether the identified kaolinite in archaeological ceramics is a product of rehydration. The model compound containing high amount of kaolinite was prepared in order to follow its changes during calcination and hydrothermal treatment. Archaeological ceramics and the model compound were treated by hydrothermal ageing and studied by XRF, XRD and IR analyses. It was proved that the presence of kaolinite in the border-parts of the archaeological object was not a product of rehydration, but that it originated from the raw materials.

Miniaturized and Ferrite Based Tunable Bandpass Filters in LCP and LTCC Technologies for SoP Applications

KAUST Repository

Arabi, Eyad A.

2015-04-01

Wireless systems with emerging applications are leaning towards small size, light-weight and low cost. Another trend for these wireless devices is that new applications and functionalities are being added without increasing the size of the device. To accomplish this, individual components must be miniaturized and the system should be designed to maximize the integration of the individual components. The high level of 3D integration feasible in system on package design (SoP) concept can fulfill the latter requirement. Bandpass filters are important components on all wireless systems to reject the unwanted signals and reduce interference. Being mostly implemented with passive and distributed components, bandpass filters take considerable space in a wireless system. Moreover, with emerging bands and multiple applications encompassed in a single device, many bandpass filters are required. The miniaturization related to bandpass filters can be approached by three main ways: (1) at the component level through the miniaturization of individual bandpass filters, (2) at the system level through the use of tunable filters to reduce the overall number of filters, and (3) at the system level through the high level of integration in a 3D SoP platform. In this work we have focused on all three aspects of miniaturization of band pass filters mentioned above. In the first part of this work, a low frequency (1.5 GHz global positioning system (GPS) band) filter implemented through 3D lumped components in two leading SoP technologies, namely low temperature co-fired ceramic (LTCC) and the liquid crystal polymers (LCP) is demonstrated. The miniaturized filter is based on a second order topology, which has been modified to improve the selectivity and out-of-band rejection without increasing the size. Moreover, for the case of LCP, the filter is realized in an ultra-thin stack up comprising four metallization layers with an overall thickness of only 100 _m. Due to its ultra

Firing: the proof test for ceramic processing

International Nuclear Information System (INIS)

Kingery, W.D.

1975-01-01

The object of ceramic processing is to form ware having certain shapes and properties. Thus, one test of the success of processing procedures must be in terms of the resulting structure and characteristics of a material after firing. During the firing process some few variations resulting from processing may be evened out, but the great majority of variation tends to be amplified. Examination of a few cases illustrates the nature of the defect amplification process. (U.S.)

Ceramic core–shell composites with modified mechanical properties prepared by thermoplastic co-extrusion

Czech Academy of Sciences Publication Activity Database

Kaštyl, J.; Chlup, Zdeněk; Clemens, F.; Trunec, M.

2015-01-01

Roč. 35, č. 10 (2015), s. 2873-2881 ISSN 0955-2219 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Alumina * Zirconia toughened alumina * Co-extrusion * Composite * Mechanical properties1 Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 2.933, year: 2015

3-Axis Fully-Integrated Capacitive Tactile Sensor with Flip-Bonded CMOS on LTCC Interposer.

Science.gov (United States)

Asano, Sho; Muroyama, Masanori; Nakayama, Takahiro; Hata, Yoshiyuki; Nonomura, Yutaka; Tanaka, Shuji

2017-10-25

This paper reports a 3-axis fully integrated differential capacitive tactile sensor surface-mountable on a bus line. The sensor integrates a flip-bonded complementary metal-oxide semiconductor (CMOS) with capacitive sensing circuits on a low temperature cofired ceramic (LTCC) interposer with Au through vias by Au-Au thermo-compression bonding. The CMOS circuit and bonding pads on the sensor backside were electrically connected through Au bumps and the LTCC interposer, and the differential capacitive gap was formed by an Au sealing frame. A diaphragm for sensing 3-axis force was formed in the CMOS substrate. The dimensions of the completed sensor are 2.5 mm in width, 2.5 mm in length, and 0.66 mm in thickness. The fabricated sensor output coded 3-axis capacitive sensing data according to applied 3-axis force by three-dimensional (3D)-printed pins. The measured sensitivity was as high as over 34 Count/mN for normal force and 14 to 15 Count/mN for shear force with small noise, which corresponds to less than 1 mN. The hysteresis and the average cross-sensitivity were also found to be less than 2% full scale and 11%, respectively.

Synthesis of submicron silver powder from scrap low-temperature co-fired ceramic an e-waste: Understanding the leaching kinetics and wet chemistry.

Science.gov (United States)

Swain, Basudev; Shin, Dongyoon; Joo, So Yeong; Ahn, Nak Kyoon; Lee, Chan Gi; Yoon, Jin-Ho

2018-03-01

The current study focuses on the understanding of leaching kinetics of metal in the LTCC in general and silver leaching in particular along with wet chemical reduction involving silver nanoparticle synthesis. Followed by metal leaching, the silver was selectively precipitated using HCl as AgCl. The precipitated AgCl was dissolved in ammonium hydroxide and reduced to pure silver metal nanopowder (NPs) using hydrazine as a reductant. Polyvinylpyrrolidone (PVP) used as a stabilizer and Polyethylene glycol (PEG) used as reducing reagent as well as stabilizing reagent to control size and shape of the Ag NPs. An in-depth investigation indicated a first-order kinetics model fits well with high accuracy among all possible models. Activation energy required for the first order reaction was 21.242 kJ mol -1 for Silver. PVP and PEG 1% each together provide better size control over silver nanoparticle synthesis using 0.4 M hydrazine as reductant, which provides relatively regular morphology in comparison to their individual application. The investigation revealed that the waste LTCC (an industrial e-waste) can be recycled through the reported process even in industrial scale. The novelty of reported recycling process is simplicity, versatile and eco-efficiency through which waste LTCC recycling can address various issues like; (i) industrial waste disposal (ii) synthesis of silver nanoparticles from waste LTCC (iii) circulate metal economy within a closed loop cycle in the industrial economies where resources are scarce, altogether. Copyright © 2017 Elsevier Ltd. All rights reserved.

Co-firing biomass and fossil fuels

International Nuclear Information System (INIS)

Junge, D.C.

1991-01-01

In June 1989, the Alaska Energy Authority and the University of Alaska Anchorage published a monograph summarizing the technology of co-firing biomass and fossil fuels. The title of the 180 page monograph is 'Use of Mixed Fuels in Direct Combustion Systems'. Highlights from the monograph are presented in this paper with emphasis on the following areas: (1) Equipment design and operational experience co-firing fuels; (2) The impact of co-firing on efficiency; (3) Environmental considerations associated with co-firing; (4) Economic considerations in co-firing; and (5) Decision making criteria for co-firing

3-Axis Fully-Integrated Capacitive Tactile Sensor with Flip-Bonded CMOS on LTCC Interposer

Directory of Open Access Journals (Sweden)

Sho Asano

2017-10-01

Full Text Available This paper reports a 3-axis fully integrated differential capacitive tactile sensor surface-mountable on a bus line. The sensor integrates a flip-bonded complementary metal-oxide semiconductor (CMOS with capacitive sensing circuits on a low temperature cofired ceramic (LTCC interposer with Au through vias by Au-Au thermo-compression bonding. The CMOS circuit and bonding pads on the sensor backside were electrically connected through Au bumps and the LTCC interposer, and the differential capacitive gap was formed by an Au sealing frame. A diaphragm for sensing 3-axis force was formed in the CMOS substrate. The dimensions of the completed sensor are 2.5 mm in width, 2.5 mm in length, and 0.66 mm in thickness. The fabricated sensor output coded 3-axis capacitive sensing data according to applied 3-axis force by three-dimensional (3D-printed pins. The measured sensitivity was as high as over 34 Count/mN for normal force and 14 to 15 Count/mN for shear force with small noise, which corresponds to less than 1 mN. The hysteresis and the average cross-sensitivity were also found to be less than 2% full scale and 11%, respectively.

Biomass co-firing opportunities and experiences

Energy Technology Data Exchange (ETDEWEB)

Lyng, R. [Ontario Power Generation Inc., Niagara Falls, ON (Canada). Nanticoke Generating Station

2006-07-01

Biomass co-firing and opportunities in the electricity sector were described in this presentation. Biomass co-firing in a conventional coal plant was first illustrated. Opportunities that were presented included the Dutch experience and Ontario Power Generation's (OPG) plant and production mix. The biomass co-firing program at OPG's Nantucket generating station was presented in three phases. The fuel characteristics of co-firing were identified. Several images and charts of the program were provided. Results and current status of tests were presented along with conclusions of the biomass co-firing program. It was concluded that biomass firing is feasible and following the Dutch example. Biomass firing could considerably expand renewable electricity generation in Ontario. In addition, sufficient biomass exists in Ontario and the United States to support large scale biomass co-firing. Several considerations were offered such as electricity market price for biomass co-firing and intensity targets and credit for early adoption and banking. tabs., figs.

[Effects of repeated firing on microleakage of selective laser melting ceramic crowns].

Science.gov (United States)

Zhong, Qun; Peng, Yan; Wu, Xue-Ying; Weng, Jia-Wei

2016-12-01

To investigate the effects of repeated firing on microleakage of selective laser melting ceramic crowns. Fifty molars were randomly divided into 2 groups (25 teeth in each group). Teeth in group A received a chamfer finish line preparation, whereas teeth in group B received a shoulder finish line. After SLM metal crowns were fabricated, all the crowns received initial oxidation step, opaque firing, dentin firing and glaze firing, then crowns in each group were randomly divided into 5 sub-groups according to different time of clinical firings. Glass ionomer was applied for bonding. After 5000 thermocycles ranging from 5degrees centigrade to 55degrees centigrade, all the specimens was evaluated by dye penetration and then microleakage was examined under light microscopy. The data were analyzed with SPSS 20.0 software package. Microleakage between all specimens of group A were not statistically significant (P>0.05) whereas that of group B were statistically significant (P<0.05); After the fifth time of clinical firing, microleakage of specimens in group B(B5) were significantly higher than that of group A(A5). Repeated firings had no significant influence on marginal microleakage of SLM ceramic crowns whereas the crowns of chamfer finish lines result in better clinical performance after repeated firings.

3-Axis Fully-Integrated Capacitive Tactile Sensor with Flip-Bonded CMOS on LTCC Interposer †

Science.gov (United States)

Asano, Sho; Nakayama, Takahiro; Hata, Yoshiyuki; Tanaka, Shuji

2017-01-01

This paper reports a 3-axis fully integrated differential capacitive tactile sensor surface-mountable on a bus line. The sensor integrates a flip-bonded complementary metal-oxide semiconductor (CMOS) with capacitive sensing circuits on a low temperature cofired ceramic (LTCC) interposer with Au through vias by Au-Au thermo-compression bonding. The CMOS circuit and bonding pads on the sensor backside were electrically connected through Au bumps and the LTCC interposer, and the differential capacitive gap was formed by an Au sealing frame. A diaphragm for sensing 3-axis force was formed in the CMOS substrate. The dimensions of the completed sensor are 2.5 mm in width, 2.5 mm in length, and 0.66 mm in thickness. The fabricated sensor output coded 3-axis capacitive sensing data according to applied 3-axis force by three-dimensional (3D)-printed pins. The measured sensitivity was as high as over 34 Count/mN for normal force and 14 to 15 Count/mN for shear force with small noise, which corresponds to less than 1 mN. The hysteresis and the average cross-sensitivity were also found to be less than 2% full scale and 11%, respectively. PMID:29068429

Processing, microstructure, and electric properties of buried resistors in low-temperature co-fired ceramics

International Nuclear Information System (INIS)

Yang, Pin; Rodriguez, Mark A.; Kotula, Paul; Miera, Brandon K.; Dimos, Duane

2001-01-01

The electrical properties of ruthenium oxide based devitrifiable resistors embedded within low-temperature co-fired ceramics were investigated from -100 o C to 100 o C. Special attention was given to the processing conditions and their effects on resistance and temperature coefficient of resistance (TCR). Results indicate that within this temperature range the conductance for these buried resistors is limited by tunneling of charge carriers through the thin glass layer between ruthenium oxide particles. A modified version of the tunneling barrier model is proposed to account for the microstructure ripening observed during thermal processing. The model parameters determined from curve fitting show that charging energy (i.e., the energy required for a charge carrier to tunnel through the glass barrier) is strongly dependent on particle size and particle--particle separation between ruthenium oxide grains. Initial coarsening of ruthenium oxide grains was found to reduce the charging energy and lower the resistance. However, when extended ripening occurs, the increase in particle--particle separation increases the charging energy, reduces the tunneling probability and gives rise to a higher resistance. The tradeoff between these two effects results in an optimum microstructure with a minimum resistance and TCR. Furthermore, the TCR of these buried resistors has been shown to be governed by the magnitude of the charging energy. Model parameters determined by our analysis appear to provide quantitative physical interpretations to the microstructural changes in the resistor, which in turn, are controlled by the processing conditions

Ceramic fiber blanket wrap for fire protection of cable trays and conduits

International Nuclear Information System (INIS)

Chaille, C.E.; Reiman, R.J.

1980-01-01

In some areas of nuclear power plants, cables of redundant electrical systems, which are necessary for the safe shutdown of the reactor, are in close proximity. If a fire should occur in one of these areas, both electrical systems could be destroyed before the fire is extinguished and control of the reactor may be lost. A ceramic fiber blanket was evaluated as a fire protective wrap around cable trays and conduits. 2 refs

Biomass co-firing under oxy-fuel conditions

DEFF Research Database (Denmark)

Álvarez, L.; Yin, Chungen; Riaza, J.

2014-01-01

This paper presents an experimental and numerical study on co-firing olive waste (0, 10%, 20% on mass basis) with two coals in an entrained flow reactor under three oxy-fuel conditions (21%O2/79%CO2, 30%O2/70%CO2 and 35%O2/65%CO2) and air–fuel condition. Co-firing biomass with coal was found...... to have favourable synergy effects in all the cases: it significantly improves the burnout and remarkably lowers NOx emissions. The reduced peak temperatures during co-firing can also help to mitigate deposition formation in real furnaces. Co-firing CO2-neutral biomass with coals under oxy-fuel conditions...... the model can be used to aid in design and optimization of large-scale biomass co-firing under oxy-fuel conditions....

Formulation and screen printing of water based conductive flake silver pastes onto green ceramic tapes for electronic applications

International Nuclear Information System (INIS)

Faddoul, Rita; Reverdy-Bruas, Nadège; Blayo, Anne

2012-01-01

Highlights: ► Formulation of water-based pastes. ► Viscosity, yield stress, elastic and viscous modulus determination. ► Screen printing onto green ceramic tapes. ► Rheology effect on line dimensions and electrical properties. ► Resistivity ∼18–33 nΩ m. Minimum width ∼60 μm after sintering. - Abstract: Environmentally friendly, water-based silver pastes, adapted for screen printing, were formulated with different silver contents (67–75%). These pastes allowed screen printing onto low temperature co-fired ceramic (LTCC) of narrow conductive tracks with a 60 μm line width and a 3 × 10 −8 Ω m electrical resistivity. Inks were formulated with a mixture of spherical and flake shape silver particles with 2–4 μm mean diameter. Rheological behaviour of pastes was studied in order to determine its effect on printed lines properties. Prepared inks were then screen printed and sintered under normal atmosphere at 875 °C. As expected, electrical properties depended on silver content. Resistivity values varying from 1.6 × 10 −8 to 3.3 × 10 −8 Ω m were calculated over 36.3 cm line length. These values are very close to bulk silver resistivity (1.6 × 10 −8 Ω m). Compared to previous research and commercial pastes, the newly formulated pastes reached equivalent or even better conductivities with lower silver content (70% by weight).

Influence of heating rate and temperature firing on the properties of bodies of red ceramic

International Nuclear Information System (INIS)

Silva, B.J. da; Goncalves, W.P.; Cartaxo, J.M.; Macedo, R.S.; Neves, G.A.; Santana, L.N.L.; Menezes, R.R.

2011-01-01

In the red ceramic industry, the firing is one of the main stages of the production process. There are two heating rates prevailing at this stage: the slow (traditional ceramics) and fast. The slow rate more used in Brazil, is considered delayed. This study aims to evaluate the influence of particle size and chemical composition of three mixture of clay, used in the manufacture of red ceramic products and to study the influence of the firing temperature on their technological properties. When subjected to heating rates slow and fast. Initially, the mixtures were characterized subsequently were extruded, dried and subjected to firing at temperatures of 900 and 1000 ° C with heating rates of 5, 20 and 30 °C/min. The results indicated that the chemical composition and particle size influenced significantly the technological properties and that the bodies obtained with the paste that had lower levels of flux showed better stability. (author)

Ultralight and fire-resistant ceramic nanofibrous aerogels with temperature-invariant superelasticity.

Science.gov (United States)

Si, Yang; Wang, Xueqin; Dou, Lvye; Yu, Jianyong; Ding, Bin

2018-04-01

Ultralight aerogels that are both highly resilient and compressible have been fabricated from various materials including polymer, carbon, and metal. However, it has remained a great challenge to realize high elasticity in aerogels solely based on ceramic components. We report a scalable strategy to create superelastic lamellar-structured ceramic nanofibrous aerogels (CNFAs) by combining SiO 2 nanofibers with aluminoborosilicate matrices. This approach causes the random-deposited SiO 2 nanofibers to assemble into elastic ceramic aerogels with tunable densities and desired shapes on a large scale. The resulting CNFAs exhibit the integrated properties of flyweight densities of >0.15 mg cm -3 , rapid recovery from 80% strain, zero Poisson's ratio, and temperature-invariant superelasticity to 1100°C. The integral ceramic nature also provided the CNFAs with robust fire resistance and thermal insulation performance. The successful synthesis of these fascinating materials may provide new insights into the development of ceramics in a lightweight, resilient, and structurally adaptive form.

Ceramic Defects in Metal-Ceramic Fixed Dental Prostheses Made from Co-Cr and Au-Pt Alloys: A Retrospective Study.

Science.gov (United States)

Mikeli, Aikaterini; Boening, Klaus W; Lißke, Benjamin

2015-01-01

Ceramic defects in porcelain-fused-to-metal (PFM) restorations may depend on framework alloy type. This study assessed ceramic defects on cobalt-chromium- (Co-Cr-) and gold-platinum- (Au-Pt-) based PFM restorations. In this study, 147 Co-Cr-based and 168 Au-Pt-based PFM restorations inserted between 1998 and 2010 (139 patients) were examined for ceramic defects. Detected defects were assigned to three groups according to clinical defect relevance. Ceramic defect rates (Co-Cr-based: 12.9%; Au-Pt-based: 7.2%) revealed no significant difference but a strong statistical trend (U test, P = .082). Most defects were of little clinical relevance. Co-Cr PFM restorations may be at higher risk for ceramic defects compared to Au-Pt-based restorations.

Reverse Engineering of Corinthian Pigment Processing and Firing Technologies on Archaic Polychrome Ceramics

Science.gov (United States)

Klesner, Catherine Elizabeth

Decorative, polychrome ceramics from Corinth, Greece, produced during the 8th-6th centuries B.C.E. are luxury goods that were widely traded throughout Greece and the Mediterranean. The decorated ceramics were produced in a variety of shapes, including aryballos, alabastron, and olpe. They were decorated with slip-glazes in distinctive white, black, red, yellow, and purple colors, and in a variety of surface finishes, matte, semi-matte and glossy. Artisans in Corinthian workshops experimented to change the colors of the slips by varying the type and amount of iron-rich raw materials. They also varied the composition of the clay used as a binder and the amount of flux used as a sintering aid to promote glass formation. This research reconstructs the technology used by the Corinthian craftsmen to produce the Archaic polychrome ceramics, and shows how these technologies differed from the production of better known, more prestigious Athenian black-figure and red-figure ceramics. Through microstructural examination of archaeological samples and replication experiments, this thesis proposes that the purple iron oxide pigment is the result of acid treatment and oxidation of iron metal. The firing temperature range of the Corinthian polychrome ceramics was determined experimentally to be 925-1025°C, which is higher than previously reported and similar to that reported for Corinthian transport amphoras. The firing range is higher by 50-150°C than the Athenian black-figure and red-figure ceramics. Samples of Corinthian polychrome and Athenian black-figure ceramics from the Marie Farnsworth collection at the University of Arizona were tested and compared to Corinthian clay collections. Analytical techniques included Fourier-transform infrared spectroscopy (FTIR), scanning-electron microscopy with energy-dispersive spectroscopy (SEM-EDS), micro-Raman spectroscopy, and wavelength-dispersive electron microprobe (EPMA with BSE-SEM).

Effects of body formulation and firing temperature to properties of ceramic tile incorporated with electric arc furnace (EAF) slag waste

Science.gov (United States)

Sharif, Nurulakmal Mohd; Lim, Chi Yang; Teo, Pao Ter; Seman, Anasyida Abu

2017-07-01

Significant quantities of sludge and slag are generated as waste materials or by-products from steel industries. One of the by-products is Electric Arc Furnace (EAF) steel slag which consists of oxides such as CaO, Al2O3 and FeO. This makes it possible for slag to partially replace the raw materials in ceramic tile production. In our preliminary assessment of incorporating the EAF slag into ceramic tile, it was revealed that at fixed firing temperature of 1150°C, the tile of composition 40 wt.% EAF slag - 60 wt.% ball clay has comparable properties with commercial ceramic tile. Thus, this current study would focus on effects of body formulation (different weight percentages of K-feldspar and silica) and different firing temperatures to properties of EAF slag added ceramic tile. EAF slag from Southern Steel Berhad (SSB) was crushed into micron size (EAF slag content was 40 wt.%) and milled with ball clay, K-feldspar and silica before compacted and fired at 1125°C and 1150°C. The EAF slag added tile was characterized in terms of water absorption, apparent porosity, bulk density, modulus of rupture (MOR) and phase analysis via X-ray diffraction (XRD). The composition of 40 wt.% EAF slag - 30 wt.% ball clay - 10 wt.% K-feldspar - 20 wt.% silica (10F_20S), fired at 1150°C showed the lowest water absorption, apparent porosity and highest bulk density due to enhancement of densification process during firing. However, the same composition of ceramic tile (10F_20S) had the highest MOR at lower firing temperature of 1125°C, contributed by presence of the highest total amount of anorthite and wollastonite reinforcement crystalline phases (78.40 wt.%) in the tile. Overall, both the water absorption and MOR of all ceramic tiles surpassed the requirement regulated by MS ISO 13006:2014 Standard (Annex G: Dry-pressed ceramic tile with low water absorption, Eb ≤ 0.50 % and minimum MOR of 35 MPa).

Evaluating the sustainability of co-firing in the UK

Energy Technology Data Exchange (ETDEWEB)

Woods, Jeremy; Tipper, Richard; Brown, Gareth; Diaz-Chavez, Rocio; Lovell, Jessica; de Groot, Peter

2006-10-09

The objectives of the study were: Assess the overall carbon balance for co-firing; Investigate the other sustainability issues relating to co-firing; Assess the scope for incentivising the most sustainable forms of co-firing. The main questions to be addressed were: Is the overall carbon balance for co-firing positive? What is the difference in carbon balance between energy crops and other biomass? Are some kinds of energy crops better than others? How big a factor is transport in the carbon balance? Under what circumstances (fuel, transport, process, etc.) are the greatest benefits of co-firing in terms of carbon balance and sustainability? Are there any circumstances (as above) that could raise serious carbon balance or sustainability issues? How does the carbon balance compare between co-firing, dedicated biomass, and biomass heat? Is there any scope for encouraging the most sustainable forms of co-firing - perhaps through using existing or currently in development accreditation schemes? The report concludes that: Co-firing could be expanded to make a significant and low risk contribution to Government and EU renewable energy policy targets; Real environmental and social benefits could arise from the expansion of co-firing markets, both in the UK and in poor developing countries, given responsible development policy; There is no clear environmental or social case, for an arbitrary cap on the amount of co-firing; Co-firing could expand and enhance clean coal Carbon and Capture and Sequestration (CCS). This report focuses solely on the carbon (GHG) and broader sustainability impacts of co-firing in the UK. It does not include an economic evaluation. It provides an overview of the existing materials being used as feedstocks for co-firing and a summary life-cycle assessment of the GHG balances and sustainability (environmental and social) impacts of the provision and use of those feedstocks. A clear distinction is made between the use of residues and dedicated

Evaluating the sustainability of co-firing in the UK

International Nuclear Information System (INIS)

Woods, Jeremy; Tipper, Richard; Brown, Gareth; Diaz-Chavez, Rocio; Lovell, Jessica; de Groot, Peter

2006-01-01

The objectives of the study were: Assess the overall carbon balance for co-firing; Investigate the other sustainability issues relating to co-firing; Assess the scope for incentivising the most sustainable forms of co-firing. The main questions to be addressed were: Is the overall carbon balance for co-firing positive? What is the difference in carbon balance between energy crops and other biomass? Are some kinds of energy crops better than others? How big a factor is transport in the carbon balance? Under what circumstances (fuel, transport, process, etc.) are the greatest benefits of co-firing in terms of carbon balance and sustainability? Are there any circumstances (as above) that could raise serious carbon balance or sustainability issues? How does the carbon balance compare between co-firing, dedicated biomass, and biomass heat? Is there any scope for encouraging the most sustainable forms of co-firing - perhaps through using existing or currently in development accreditation schemes? The report concludes that: Co-firing could be expanded to make a significant and low risk contribution to Government and EU renewable energy policy targets; Real environmental and social benefits could arise from the expansion of co-firing markets, both in the UK and in poor developing countries, given responsible development policy; There is no clear environmental or social case, for an arbitrary cap on the amount of co-firing; Co-firing could expand and enhance clean coal Carbon and Capture and Sequestration (CCS). This report focuses solely on the carbon (GHG) and broader sustainability impacts of co-firing in the UK. It does not include an economic evaluation. It provides an overview of the existing materials being used as feedstocks for co-firing and a summary life-cycle assessment of the GHG balances and sustainability (environmental and social) impacts of the provision and use of those feedstocks. A clear distinction is made between the use of residues and dedicated

Investigation of firing temperature variation in ovens for ceramic-fused-to-metal dental prostheses using swept source optical coherence tomography

Science.gov (United States)

Todor, Raluca; Negrutiu, Meda-Lavinia; Sinescu, Cosmin; Topala, Florin Ionel; Bradu, Adrian; Duma, Virgil-Florin; Romînu, Mihai; Podoleanu, Adrian G.

2018-03-01

One of the most common fabrication techniques for dental ceramics is sintering, a process of heating of the ceramic to ensure densification. This occurs by viscous flow when the firing temperature is reached. Acceptable restorations require the alloy and ceramic to be chemically, thermally, mechanically, and aesthetically compatible. Thermal and mechanical compatibility include a fusing temperature of ceramic that does not cause distortion of the metal substructure. Decalibration of ovens used for firing of the ceramic layers for metal ceramic dental prostheses leads to stress and cracks in the veneering material, and ultimately to the failure of the restoration. 25 metal ceramic prostheses were made for this study. They were divided in five groups, each sintered at a different temperature: a group at the temperature prescribed by the producer, two groups at lower and two groups at higher temperatures set in the ceramic oven. An established noninvasive biomedical imaging method, swept source (SS) optical coherence tomography (OCT) was employed, in order to evaluate the modifications induced when using temperatures different from those prescribed for firing the samples. A quantitative assessment of the probes is performed by en-face OCT images, taken at constant depths inside the samples. The differences in granulation, thus in reflectivity allow for extracting rules-of-thumb to evaluate fast, by using only the prostheses currently produced the current calibration of the ceramic oven. OCT imaging can allow quick identification of the oven decalibration, to avoid producing dental prostheses with defects.

Ferrite LTCC-based antennas for tunable SoP applications

KAUST Repository

Shamim, Atif; Bray, Joey R.; Hojjat, Nasrin; Roy, Langis

2011-01-01

tunable system-on-package applications. Measurements of rectangular microstrip patch antennas on a ferrite LTCC substrate display a maximum tuning range of 610 MHz near 12 GHz. Two different bias windings and their effect on the antenna performance

Ash transformation in suspension fired boilers co-firing coal and straw

DEFF Research Database (Denmark)

Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

In this literature report is provided a status for the present knowledge level on ash properties when co-firing coal and biomass. The fly ash formed in boilers using co-firing of coal and straw do have a large influence on ash deposit formation, boiler corrosion, fly ash utilization and operation...

GASIFICATION BASED BIOMASS CO-FIRING - PHASE I

Energy Technology Data Exchange (ETDEWEB)

Babul Patel; Kevin McQuigg; Robert F. Toerne

2001-12-01

Biomass gasification offers a practical way to use this locally available fuel source for co-firing traditional large utility boilers. The gasification process converts biomass into a low Btu producer gas that can be fed directly into the boiler. This strategy of co-firing is compatible with variety of conventional boilers including natural gas fired boilers as well as pulverized coal fired and cyclone boilers. Gasification has the potential to address all problems associated with the other types of co-firing with minimum modifications to the existing boiler systems. Gasification can also utilize biomass sources that have been previously unsuitable due to size or processing requirements, facilitating a reduction in the primary fossil fuel consumption in the boiler and thereby reducing the greenhouse gas emissions to the atmosphere.

Effect of fuel type and deposition surface temperature on the growth and structure of ash deposit collected during co-firing of coal with sewage-sludge, saw-dust and refuse derived fuel

Energy Technology Data Exchange (ETDEWEB)

Kupka, Tomasz; Zajac, Krzysztof; Weber, Roman [Clausthal Univ. of Technology, Clausthal-Zellerfeld (Germany). Inst. of Energy Process Engineering and Fuel Technology

2008-07-01

Blends of a South African bituminous ''Middleburg'' coal and three alternative fuels (a municipal sewage-sludge, a saw-dust and a refuse derived fuel) have been fired in the slagging reactor to examine the effect of the added fuel on slagging propensity of the mixtures. Two kinds of deposition probes have been used, un-cooled ceramic probes and air-cooled steal probes. Distinct differences in physical and chemical structures of the deposits collected using the un-cooled ceramic probes and air-cooled metal probes have been observed. Glassy, easily molten deposits collected on un-cooled ceramic deposition probes were characteristic for co-firing of municipal sewage-sludge with coal. Porous, sintered (not molten) but easily removable deposits of the same fuel blend have been collected on the air-cooled metal deposition probes. Loose, easy removable deposits have been sampled on air-cooled metal deposition probe during co-firing of coal/saw-dust blends. The mass of the deposit sampled at lower surface temperatures (550-700 C) was always larger than the mass sampled at higher temperatures (1100-1300 C) since the higher temperature ash agglomerated and sintered much faster than the low temperature deposit. (orig.)

Coating system to permit direct brazing of ceramics

Science.gov (United States)

Cadden, Charles H.; Hosking, F. Michael

2003-01-01

This invention relates to a method for preparing the surface of a ceramic component that enables direct brazing using a non-active braze alloy. The present invention also relates to a method for directly brazing a ceramic component to a ceramic or metal member using this method of surface preparation, and to articles produced by using this brazing method. The ceramic can be high purity alumina. The method comprises applying a first coating of a silicon-bearing oxide material (e.g. silicon dioxide or mullite (3Al.sub.2 O.sub.3.2SiO.sub.2) to the ceramic. Next, a thin coating of active metal (e.g. Ti or V) is applied. Finally, a thicker coating of a non-active metal (e.g. Au or Cu) is applied. The coatings can be applied by physical vapor deposition (PVD). Alternatively, the active and non-active metals can be co-deposited (e.g. by sputtering a target made of mullite). After all of the coatings have been applied, the ceramic can be fired at a high temperature in a non-oxidizing environment to promote diffusion, and to enhance bonding of the coatings to the substrate. After firing, the metallized ceramic component can be brazed to other components using a conventional non-active braze alloy. Alternatively, the firing and brazing steps can be combined into a single step. This process can replace the need to perform a "moly-manganese" metallization step.

Corrosion and Materials Performance in biomass fired and co-fired power plants

DEFF Research Database (Denmark)

Montgomery, Melanie; Larsen, OH; Biede, O

2003-01-01

not previously encountered in coal-fired power plants. The type of corrosion attack can be directly ascribed to the composition of the deposit and the metal surface temperature. In woodchip boilers, a similar corrosion rate and corrosion mechanism has on some occasions been observed. Co-firing of straw (10...... and 20% energy basis) with coal has shown corrosion rates lower than those in straw-fired plants. With both 10 and 20% straw, no chlorine corrosion was seen. This paper will describe the results from in situ investigations undertaken in Denmark on high temperature corrosion in biomass fired plants....... Results from 100% straw-firing, woodchip and co-firing of straw with coal will be reported. The corrosion mechanisms observed are summarized and the corrosion rates for 18-8 type stainless steels are compared....

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.

Portfolio: Ceramics.

Science.gov (United States)

Hardy, Jane; And Others

1982-01-01

Describes eight art activities using ceramics. Elementary students created ceramic tiles to depict ancient Egyptian and medieval European art, made ceramic cookie stamps, traced bisque plates on sketch paper, constructed clay room-tableaus, and designed clay relief masks. Secondary students pit-fired ceramic pots and designed ceramic Victorian…

Quantitative firing transformations of a triaxial ceramic by X-ray diffraction methods

Directory of Open Access Journals (Sweden)

M. S. Conconi

2014-12-01

Full Text Available The firing transformations of traditional (clay based ceramics are of technological and archeological interest, and are usually reported qualitatively or semiquantitatively. These kinds of systems present an important complexity, especially for X-ray diffraction techniques, due to the presence of fully crystalline, low crystalline and amorphous phases. In this article we present the results of a qualitative and quantitative X-ray diffraction Rietveld analysis of the fully crystalline (kaolinite, quartz, cristobalite, feldspars and/or mullite, the low crystalline (metakaolinite and/or spinel type pre-mullite and glassy phases evolution of a triaxial (clay-quartz-feldspar ceramic fired in a wide temperature range between 900 and 1300 ºC. The employed methodology to determine low crystalline and glassy phase abundances is based in a combination of the internal standard method and the use of a nanocrystalline model where the long-range order is lost, respectively. A preliminary sintering characterization was carried out by contraction, density and porosity evolution with the firing temperature. Simultaneous thermo-gravimetric and differential thermal analysis was carried out to elucidate the actual temperature at which the chemical changes occur. Finally, the quantitative analysis based on the Rietveld refinement of the X-ray diffraction patterns was performed. The kaolinite decomposition into metakaolinite was determined quantitatively; the intermediate (980 ºC spinel type alumino-silicate formation was also quantified; the incongruent fusion of the potash feldspar was observed and quantified together with the final mullitization and the amorphous (glassy phase formation.The methodology used to analyze the X-ray diffraction patterns proved to be suitable to evaluate quantitatively the thermal transformations that occur in a complex system like the triaxial ceramics. The evaluated phases can be easily correlated with the processing variables and

Quantitative firing transformations of a triaxial ceramic by X-ray diffraction methods

International Nuclear Information System (INIS)

Conconi, M.S.; Gauna, M.R.; Serra, M.F.; Suarez, G.; Aglietti, E.F.; Rendtorff, N.M.

2014-01-01

The firing transformations of traditional (clay based) ceramics are of technological and archaeological interest, and are usually reported qualitatively or semi quantitatively. These kinds of systems present an important complexity, especially for X-ray diffraction techniques, due to the presence of fully crystalline, low crystalline and amorphous phases. In this article we present the results of a qualitative and quantitative X-ray diffraction Rietveld analysis of the fully crystalline (kaolinite, quartz, cristobalite, feldspars and/or mullite), the low crystalline (metakaolinite and/or spinel type pre-mullite) and glassy phases evolution of a triaxial (clay-quartz-feldspar) ceramic fired in a wide temperature range between 900 and 1300 deg C. The employed methodology to determine low crystalline and glassy phase abundances is based in a combination of the internal standard method and the use of a nanocrystalline model where the long-range order is lost, respectively. A preliminary sintering characterization was carried out by contraction, density and porosity evolution with the firing temperature. Simultaneous thermo-gravimetric and differential thermal analysis was carried out to elucidate the actual temperature at which the chemical changes occur. Finally, the quantitative analysis based on the Rietveld refinement of the X-ray diffraction patterns was performed. The kaolinite decomposition into metakaolinite was determined quantitatively; the intermediate (980 deg C) spinel type alumino-silicate formation was also quantified; the incongruent fusion of the potash feldspar was observed and quantified together with the final mullitization and the amorphous (glassy) phase formation.The methodology used to analyze the X-ray diffraction patterns proved to be suitable to evaluate quantitatively the thermal transformations that occur in a complex system like the triaxial ceramics. The evaluated phases can be easily correlated with the processing variables and materials

Quantitative firing transformations of a triaxial ceramic by X-ray diffraction methods

Energy Technology Data Exchange (ETDEWEB)

Conconi, M.S.; Gauna, M.R.; Serra, M.F. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC), Buenos Aires (Argentina); Suarez, G.; Aglietti, E.F.; Rendtorff, N.M., E-mail: rendtorff@cetmic.unlp.edu.ar [Universidad Nacional de La Plata (UNLP), Buenos Aires (Argentina). Fac. de Ciencias Exactas. Dept. de Quimica

2014-10-15

The firing transformations of traditional (clay based) ceramics are of technological and archaeological interest, and are usually reported qualitatively or semi quantitatively. These kinds of systems present an important complexity, especially for X-ray diffraction techniques, due to the presence of fully crystalline, low crystalline and amorphous phases. In this article we present the results of a qualitative and quantitative X-ray diffraction Rietveld analysis of the fully crystalline (kaolinite, quartz, cristobalite, feldspars and/or mullite), the low crystalline (metakaolinite and/or spinel type pre-mullite) and glassy phases evolution of a triaxial (clay-quartz-feldspar) ceramic fired in a wide temperature range between 900 and 1300 deg C. The employed methodology to determine low crystalline and glassy phase abundances is based in a combination of the internal standard method and the use of a nanocrystalline model where the long-range order is lost, respectively. A preliminary sintering characterization was carried out by contraction, density and porosity evolution with the firing temperature. Simultaneous thermo-gravimetric and differential thermal analysis was carried out to elucidate the actual temperature at which the chemical changes occur. Finally, the quantitative analysis based on the Rietveld refinement of the X-ray diffraction patterns was performed. The kaolinite decomposition into metakaolinite was determined quantitatively; the intermediate (980 deg C) spinel type alumino-silicate formation was also quantified; the incongruent fusion of the potash feldspar was observed and quantified together with the final mullitization and the amorphous (glassy) phase formation.The methodology used to analyze the X-ray diffraction patterns proved to be suitable to evaluate quantitatively the thermal transformations that occur in a complex system like the triaxial ceramics. The evaluated phases can be easily correlated with the processing variables and materials

Benefits of Allothermal Biomass Gasification for Co-Firing

Energy Technology Data Exchange (ETDEWEB)

Van der Meijden, C.M.; Van der Drift, A.; Vreugdenhil, B.J. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

2012-04-15

Many countries have set obligations to reduce the CO2 emissions from coal fired boilers. Co-firing of biomass in existing coal fired power plants is an attractive solution to reduce CO2 emissions. Co-firing can be done by direct mixing of biomass with coal (direct co-firing) or by converting the biomass into a gas or liquid which is fired in a separate burner (indirect co-firing). Direct co-firing is a rather simple solution, but requires a high quality and expensive biomass fuel (e.g. wood pellets). Indirect co-firing requires an additional installation that converts the solid biomass into a gas or liquid, but has the advantage that it can handle a wide range of cheap biomass fuels (e.g. demolition wood) and most of the biomass ash components are separated from the gas before it enters the boiler. Separation of biomass ash can prevent fouling issues in the boiler. Indirect co-firing, using biomass gasification technology, is already common practice. In Geertruidenberg (the Netherlands) a 80 MWth Lurgi CFB gasifier produces gas from demolition wood which is co-fired in the Amer PC boiler. In Ruien (Belgium) a 50 MWth Foster Wheeler fluidized bed gasifier is in operation. The Energy research Centre of the Netherlands (ECN) developed a 'second generation' allothermal gasifier called the MILENA gasifier. This gasifier has some major advantages over conventional fluidized bed gasifiers. The heating value of the produced gas is approximately 2.5 times higher than of gas produced by conventional bubbling / circulating fluidized bed gasifiers. This results in smaller adaptations to the membrane wall of the boiler for the gas injection, thus lower costs. A major disadvantage of most fluidized bed gasifiers is the incomplete conversion of the fuel. Typical fuel conversions vary between 90 and 95%. The remaining combustible material, also containing most of the biomass ash components, is blown out of the gasifier and removed from the gas stream by a cyclone to

GASIFICATION BASED BIOMASS CO-FIRING

Energy Technology Data Exchange (ETDEWEB)

Babul Patel; Kevin McQuigg; Robert Toerne; John Bick

2003-01-01

Biomass gasification offers a practical way to use this widespread fuel source for co-firing traditional large utility boilers. The gasification process converts biomass into a low Btu producer gas that can be used as a supplemental fuel in an existing utility boiler. This strategy of co-firing is compatible with a variety of conventional boilers including natural gas and oil fired boilers, pulverized coal fired conventional and cyclone boilers. Gasification has the potential to address all problems associated with the other types of co-firing with minimum modifications to the existing boiler systems. Gasification can also utilize biomass sources that have been previously unsuitable due to size or processing requirements, facilitating a wider selection of biomass as fuel and providing opportunity in reduction of carbon dioxide emissions to the atmosphere through the commercialization of this technology. This study evaluated two plants: Wester Kentucky Energy Corporation's (WKE's) Reid Plant and TXU Energy's Monticello Plant for technical and economical feasibility. These plants were selected for their proximity to large supply of poultry litter in the area. The Reid plant is located in Henderson County in southwest Kentucky, with a large poultry processing facility nearby. Within a fifty-mile radius of the Reid plant, there are large-scale poultry farms that generate over 75,000 tons/year of poultry litter. The local poultry farmers are actively seeking environmentally more benign alternatives to the current use of the litter as landfill or as a farm spread as fertilizer. The Monticello plant is located in Titus County, TX near the town of Pittsburgh, TX, where again a large poultry processor and poultry farmers in the area generate over 110,000 tons/year of poultry litter. Disposal of this litter in the area is also a concern. This project offers a model opportunity to demonstrate the feasibility of biomass co-firing and at the same time eliminate

Performance ceramic red mass containing mill scale of rolling in different firing temperatures

International Nuclear Information System (INIS)

Meller, J.G.; Arnt, A.B.C; Rocha, M.R.

2014-01-01

This study aimed to evaluate the performance of the properties of samples of red clay with addition of mill scale steel. This residue consists of oxides of iron has the function replace pigments used in ceramic materials. The mechanical strength of the sintered material can be associated with reactions that occur during sintering, leading to the formation of compounds provided with good mechanical characteristics, particle size of the components and the structure of the dough piece after the compactation. After chemical and microstructural characterization diffraction and fluorescence X-rays, this residue was added in the proportion of 1.45% of a commercial ceramic mass. The formulations were subjected to different temperatures and performance of the formulations was evaluated for physical characteristics: loss on ignition, linear firing shrinkage, water absorption, flexural strength by 3 and intensity of tone. The loss on ignition and linear firing shrinkage tests relate to the sintering temperature with the performance of the tested formulations. (author)

A 3-D miniaturized high selectivity bandpass filter in LTCC technology

KAUST Repository

Arabi, Eyad A.

2014-01-01

Transmission zeros are used to improve the roll-off factors of filters but as a consequence, the out-of-band rejection decreases. In this work, an LTCC filter design is presented which employs a series inductor (implemented as a via hole) to improve the out-of-band rejection by introducing a third transmission zero. The filter, designed for GPS band (1.57 GHz), has one of the smallest reported foot prints ((0.063×0.048×0.005)λg) and demonstrates the highest roll off factor (16.7 dB/100 MHz) for this band. With only four LTCC layers, the design is cost effective and thus highly suitable for miniaturized, ultra-thin system-on-package applications. © 2001-2012 IEEE.

Co-firing of imported wood pellets – An option to efficiently save CO2 emissions in Europe?

International Nuclear Information System (INIS)

Ehrig, Rita; Behrendt, Frank

2013-01-01

In this paper the energy and carbon footprints of pellet imports from Australia, West Canada, and Russia for co-firing in Europe are investigated. Their ecologic and economic performances are proven by applying the Belgian and UK co-firing subsidy systems, which require dedicated sustainability evaluations. Based on the modelling of different subsidy schemes and price scenarios, the present paper identifies favourable conditions for the use of biomass co-firing in Germany and Austria, which currently do not have dedicated co-firing incentives. The present paper shows that under present conditions, co-firing has a narrow financial gap to coal with −3 to 4 € Cent/kWh el and has low CO 2 mitigation costs compared to other renewables. Moreover, it is shown that co-firing is one of the most cost-attractive options to reach the EU-2020 targets. For policy makers, the support of co-firing is found to be very efficient in terms of cost-benefit ratio. It is proven that the co-firing subsidy schemes might direct supply chain decisions towards options with low energy and carbon impacts. - Highlights: • Co-firing has a low financial gap and allows for advantageous CO 2 mitigation costs compared to other renewable. • Belgian and UK's co-firing subsidies are reasonable options to promote cost-effective renewable electricity generation. • Co-firing subsidy schemes can effectively direct supply chain decisions towards low energy and carbon options

Biomass co-firing for Delta Electricity

International Nuclear Information System (INIS)

Anon

2014-01-01

Electricity generator Delta Electricity has implemented a biomass co-firing program at its Vales Point power station on the Central Coast to reduce its reliance on coal and emissions of CO 2 . The program comprises two parts: direct co-firing with coal of up to 5% biomass; and development of Continuous Biomass Converter (CBC) technology with the Crucible Group to remove technology constraints and enable much higher rates of biomass co-firing. It is talking industrial scale tests. Delta increased biomass co-firing in 2013/14 to 32,000 tonnes, up from just 3,000 tonnes the previous year, and conducted biochar co-firing trials at a rate equivalent to 400,000 tonnes per annum to demonstrate the potential of CBC technology. It reduced CO 2 emissions in 2013/14 by more than 32,000 tonnes. 'Legislation and regulations define biomass as renewable,' said Delta Electricity sustainability manager Justin Flood. 'By preferring biomass over coal, the carbon in the coal is not burnt and remains locked up.' One biomass source is wood waste that would normally go to landfill, but the primary driver of Delta's recent increase in co-firing is sawmill residues. 'Previously there was a higher value market for the residues for paper pulp. However, when that market evaporated the timber industry was left with a sizable problem in terms of what to do with its residues and the loss of revenue,' said Flood. The way greenhouse gas accounting is conducted in Australia, with carbon emissions based on site activities, makes it difficult to undertake a life cycle assessment of the program. 'However, some of the international studies looking at this issue have concluded that the net carbon emissions of the biomass system are significantly lower than the coal system because of the uptake of carbon during biomass growth,' said Flood. Delta identified two challenges, sourcing the feedstock and that biomass conversion to electricity is slightly less

[Influence of coping material selection and porcelain firing on marginal and internal fit of computer-aided design/computer- aided manufacturing of zirconia and titanium ceramic implant-supported crowns].

Science.gov (United States)

Cuiling, Liu; Liyuan, Yang; Xu, Gao; Hong, Shang

2016-06-01

This study aimed to investigate the influence of coping material and porcelain firing on the marginal and internal fit of computer-aided design/computer-aided manufacturing (CAD/CAM) of zirconia ceramic implant- and titanium ceramic implant-supported crowns. Zirconia ceramic implant (group A, n = 8) and titanium metal ceramic implant-supported crowns (group B, n = 8) were produced from copings using the CAD/CAM system. The marginal and internal gaps of the copings and crowns were measured by using a light-body silicone replica technique combined with micro-computed tomography scanning to obtain a three-dimensional image. Marginal gap (MG), horizontal marginal discrepancy (HMD), and axial wall (AW) were measured. Statistical analyses were performed using SPSS 17.0. Prior to porcelain firing, the measurements for MG, HMD, and AW of copings in group A were significantly larger than those in group B (P 0.05). Porcelain firing significantly reduced MG (P 0.05). The marginal fits of CAD/CAM zirconia ceramic implant-supported crowns were superior to those of CAD/CAM titanium ceramic-supported crowns. The fits of both the CAD/CAM zirconia ceramic implant- and titanium ceramic implant-supported crowns were obviously influenced by porcelain firing.

GASIFICATION BASED BIOMASS CO-FIRING - PHASE I; SEMIANNUAL

International Nuclear Information System (INIS)

Babul Patel; Kevin McQuigg; Robert F. Toerne

2001-01-01

Biomass gasification offers a practical way to use this locally available fuel source for co-firing traditional large utility boilers. The gasification process converts biomass into a low Btu producer gas that can be fed directly into the boiler. This strategy of co-firing is compatible with variety of conventional boilers including natural gas fired boilers as well as pulverized coal fired and cyclone boilers. Gasification has the potential to address all problems associated with the other types of co-firing with minimum modifications to the existing boiler systems. Gasification can also utilize biomass sources that have been previously unsuitable due to size or processing requirements, facilitating a reduction in the primary fossil fuel consumption in the boiler and thereby reducing the greenhouse gas emissions to the atmosphere

Evaluation of ash deposits during experimental investigation of co-firing of Bosnian coal with wooden biomass

Energy Technology Data Exchange (ETDEWEB)

Smajevic, Izet; Kazagic, Anes [JP Elektroprivreda BiH d.d., Sarajevo (Bosnia and Herzegovina); Sarajevo Univ. (Bosnia and Herzegovina). Faculty of Mechanical Engineering

2008-07-01

The paper is addressed to the development and use different criteria for evaluation of ash deposits collected during experimental co-firing of Bosnian coals with wooden biomass. Spruce saw dust was used for the co-firing tests with the Kakanj brown coal and with a lignite blend consisted of the Dubrave lignite and the Sikulje lignite. The coal/biomass mixtures at 93:7 %w and at 80:20 %w were tested. Experimental lab-scale facility PF entrained flow reactor is used for the co-firing tests. The reactor allows examination of fouling/slagging behaviors and emissions at various and infinitely variable process temperature which can be set at will in the range from ambient to 1560 C. Ash deposits are collected on two non-cooled ceramic probes and one water-cooled metal surface. Six different criteria are developed and used to evaluate behavior of the ash deposits on the probes: ash deposit shape, state and structure, which are analyzed visually - photographically and optically by a microscope, rate of adhesion and ash deposit strength, analyzed by physic acting to the ash deposits, and finally deposition rate, determined as a mass of the deposit divided by the collecting area and the time of collecting. Furthermore, chemical composition analysis and AFT of the ash deposits were also done to provide additional information on the deposits. (orig.)

Drivers of biomass co-firing in U.S. coal-fired power plants

Science.gov (United States)

Michael E. Goerndt; Francisco X. Aguilar; Kenneth Skog

2013-01-01

Substantial knowledge has been generated in the U.S. about the resource base for forest and other residue-derived biomass for bioenergy including co-firing in power plants. However, a lack of understanding regarding power plant-level operations and manager perceptions of drivers of biomass co-firing remains. This study gathered information from U.S. power plant...

Fire resistance properties of ceramic wool fiber reinforced intumescent coatings

Energy Technology Data Exchange (ETDEWEB)

Amir, N., E-mail: norlailiamir@petronas.com.my; Othman, W. M. S. W., E-mail: wamosa@gmail.com; Ahmad, F., E-mail: faizahmad@petronas.com.my [Mechanical Engineering Department, Universiti Teknologi PETRONAS Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

2015-07-22

This research studied the effects of varied weight percentage and length of ceramic wool fiber (CWF) reinforcement to fire retardant performance of epoxy-based intumescent coating. Ten formulations were developed using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL) and boric acid (BA). The mixing was conducted in two stages; powdered materials were grinded in Rocklabs mortar grinder and epoxy-mixed using Caframo mixer at low speed mixing. The samples were applied on mild steel substrate and exposed to 500°C heat inside Carbolite electric furnace. The char expansion and its physical properties were observed. Scanning electron microscopy (SEM) analyses were conducted to inspect the fiber dispersion, fiber condition and the cell structure of both coatings and chars produced. Thermogravimetric analyses (TGA) were conducted to study the thermal properties of the coating such as degradation temperature and residual weight. Fire retardant performance was determined by measuring backside temperature of substrate in 1-hour, 1000°C Bunsen burner test according to UL 1709 fire regime. The results showed that intumescent coating reinforced with CWF produced better fire resistance performance. When compared to unreinforced coating, formulation S6-15 significantly reduced steel temperature at approximately 34.7% to around 175°C. However, higher fiber weight percentage had slightly decreased fire retardant performance of the coating.

Fire resistance properties of ceramic wool fiber reinforced intumescent coatings

International Nuclear Information System (INIS)

Amir, N.; Othman, W. M. S. W.; Ahmad, F.

2015-01-01

This research studied the effects of varied weight percentage and length of ceramic wool fiber (CWF) reinforcement to fire retardant performance of epoxy-based intumescent coating. Ten formulations were developed using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL) and boric acid (BA). The mixing was conducted in two stages; powdered materials were grinded in Rocklabs mortar grinder and epoxy-mixed using Caframo mixer at low speed mixing. The samples were applied on mild steel substrate and exposed to 500°C heat inside Carbolite electric furnace. The char expansion and its physical properties were observed. Scanning electron microscopy (SEM) analyses were conducted to inspect the fiber dispersion, fiber condition and the cell structure of both coatings and chars produced. Thermogravimetric analyses (TGA) were conducted to study the thermal properties of the coating such as degradation temperature and residual weight. Fire retardant performance was determined by measuring backside temperature of substrate in 1-hour, 1000°C Bunsen burner test according to UL 1709 fire regime. The results showed that intumescent coating reinforced with CWF produced better fire resistance performance. When compared to unreinforced coating, formulation S6-15 significantly reduced steel temperature at approximately 34.7% to around 175°C. However, higher fiber weight percentage had slightly decreased fire retardant performance of the coating

Fire resistance properties of ceramic wool fiber reinforced intumescent coatings

Science.gov (United States)

Amir, N.; Othman, W. M. S. W.; Ahmad, F.

2015-07-01

This research studied the effects of varied weight percentage and length of ceramic wool fiber (CWF) reinforcement to fire retardant performance of epoxy-based intumescent coating. Ten formulations were developed using ammonium polyphosphate (APP), expandable graphite (EG), melamine (MEL) and boric acid (BA). The mixing was conducted in two stages; powdered materials were grinded in Rocklabs mortar grinder and epoxy-mixed using Caframo mixer at low speed mixing. The samples were applied on mild steel substrate and exposed to 500°C heat inside Carbolite electric furnace. The char expansion and its physical properties were observed. Scanning electron microscopy (SEM) analyses were conducted to inspect the fiber dispersion, fiber condition and the cell structure of both coatings and chars produced. Thermogravimetric analyses (TGA) were conducted to study the thermal properties of the coating such as degradation temperature and residual weight. Fire retardant performance was determined by measuring backside temperature of substrate in 1-hour, 1000°C Bunsen burner test according to UL 1709 fire regime. The results showed that intumescent coating reinforced with CWF produced better fire resistance performance. When compared to unreinforced coating, formulation S6-15 significantly reduced steel temperature at approximately 34.7% to around 175°C. However, higher fiber weight percentage had slightly decreased fire retardant performance of the coating.

Mechanism of interaction of Co-B and Fe-B melts with ceramic materials

International Nuclear Information System (INIS)

Filonov, M.R.; Anikin, D.Yu.; Pecherkin, K.A.

2003-01-01

Stability of ceramic materials has been studied in the medium of melts being rendered amorphous. Measurements of limiting wetting angle for these materials were carried out on the ceramic surface. Two conclusions were made from the results of the experiments: melt-ceramics interaction takes place mainly through the slag phase; boron nitride is the most stable ceramics for melting and pouring of melts being rendered amorphous in the air. Materials on the basis of BN were synthesized by the self-propagating high-temperature synthesis. Other refractory compounds were introduced in the ceramics composition for the purpose of improving such service properties as fire resistance, thermal resistance, mechanical strength, stability of compounds to the effect of reaction-active melts. The most promising refractory compositions were determined from the results of the studies [ru

Sodium-carbonate co-substituted hydroxyapatite ceramics

Directory of Open Access Journals (Sweden)

Zoltan Z. Zyman

2013-12-01

Full Text Available Powders of sodium-carbonate co-substituted hydroxyapatite, having sodium content in the range of 0.25–1.5 wt.% with a 0.25 wt.% step, were prepared by a precipitation-solid state reaction route. Compacts of the powders were sintered in a CO2 flow (4 mL/min at 1100 °C for 2 h. The sintered ceramics contained sodium and carbonate ions in the ranges of 0–1.5 wt.% and 1.3–6 wt.%, respectively, which are typical impurity concentrations in biological apatite. A relationship between sodium and carbonate contents and the type of carbonate substitution was found. The total carbonate content progressively increased with the sodium content. The obtained ceramics showed an AB-type carbonate substitution. However, the substitution became more B-type as the sodium content increased. As a result, the carbonation was almost B-type (94 % for the highest sodium content (1.5 wt.%.

CO sub 2 laser cutting of ceramics and metal-ceramic composites. CO sub 2 -Laserschneiden von Keramik und Metall-Keramik-Verbunden

Energy Technology Data Exchange (ETDEWEB)

Wielage, B.; Drozak, J. (Dortmund Univ. (Germany, F.R.). Lehrstuhl fuer Werkstofftechnologie)

1991-01-01

Oxide and non-oxide ceramics as well as active brazed and APS-sprayed metal-ceramic composites are cut by means of a 1500 Watt CO{sub 2} laser. In this context, the experience from ceramics cutting applications is applied to laser cutting of composites. The process parameters, which are adjusted to the property profile and the thickness of the material, permit cutting of ceramics of a maximum thickness of 10 mm with optimal cut edge quality and minimum damage to the material. The parameter sets were also optimized in the case of laser-cut active brazed and plasma-sprayed composites. In terms of roughness, composition and structure of the cut edge, composites can be optimally cut using oxygen as process gas. (orig.).

Modelling methods for co-fired pulverised fuel furnaces

Energy Technology Data Exchange (ETDEWEB)

L. Ma; M. Gharebaghi; R. Porter; M. Pourkashanian; J.M. Jones; A. Williams [University of Leeds, Leeds (United Kingdom). Energy and Resources Research Institute

2009-12-15

Co-firing of biomass and coal can be beneficial in reducing the carbon footprint of energy production. Accurate modelling of co-fired furnaces is essential to discover potential problems that may occur during biomass firing and to mitigate potential negative effects of biomass fuels, including lower efficiency due to lower burnout and NOx formation issues. Existing coal combustion models should be modified to increase reliability of predictions for biomass, including factors such as increased drag due to non-spherical particle sizes and accounting for organic compounds and the effects they have on NOx emission. Detailed biomass co-firing models have been developed and tested for a range of biomass fuels and show promising results. 32 refs., 4 figs., 3 tabs.

Co-firing: panacea or potential monster?

Energy Technology Data Exchange (ETDEWEB)

Grundy, M.; Lilley, P. [Mott MacDonald Ltd., Brighton (United Kingdom). Energy Division

2004-01-01

Co-firing with fossil fuels could well be the only practical and economic way to introduce a significant biomass contribution to UK renewables. But, in the hands of the large generators, co-firing is a potential monster, capable of destroying the carefully-constructed incentive structure for 'real' renewables such as wind power and dedicated biomass plants. Both views contain an element of truth, but the conflict between them could endanger the infant energy crop industry. 1 fig., 2 photos.

Sensors and packages based on LTCC and thick-film technology for ...

Indian Academy of Sciences (India)

After deposition, drying removes the solvent in the vehicle, allowing the part to be ... In addition to the standard LTCC dielectric materials, compatible tapes with high electric ... For jet engine eddy current radial position sensors, the severe.

CO(2), CO, and Hg emissions from the Truman Shepherd and Ruth Mullins coal fires, eastern Kentucky, USA.

Science.gov (United States)

O'Keefe, Jennifer M K; Henke, Kevin R; Hower, James C; Engle, Mark A; Stracher, Glenn B; Stucker, J D; Drew, Jordan W; Staggs, Wayne D; Murray, Tiffany M; Hammond, Maxwell L; Adkins, Kenneth D; Mullins, Bailey J; Lemley, Edward W

2010-03-01

Carbon dioxide (CO(2)), carbon monoxide (CO), and mercury (Hg) emissions were quantified for two eastern Kentucky coal-seam fires, the Truman Shepherd fire in Floyd County and the Ruth Mullins fire in Perry County. This study is one of the first to estimate gas emissions from coal fires using field measurements at gas vents. The Truman Shepherd fire emissions are nearly 1400t CO(2)/yr and 16kg Hg/yr resulting from a coal combustion rate of 450-550t/yr. The sum of CO(2) emissions from seven vents at the Ruth Mullins fire is 726+/-72t/yr, suggesting that the fire is consuming about 250-280t coal/yr. Total Ruth Mullins fire CO and Hg emissions are estimated at 21+/-1.8t/yr and >840+/-170g/yr, respectively. The CO(2) emissions are environmentally significant, but low compared to coal-fired power plants; for example, 3.9x10(6)t CO(2)/yr for a 514-MW boiler in Kentucky. Using simple calculations, CO(2) and Hg emissions from coal-fires in the U.S. are estimated at 1.4x10(7)-2.9x10(8)t/yr and 0.58-11.5t/yr, respectively. This initial work indicates that coal fires may be an important source of CO(2), CO, Hg and other atmospheric constituents.

Fabrication of LTCC based Micro Thruster for Precision Controlled Spaceflight

DEFF Research Database (Denmark)

Larsen, Jack; Jørgensen, John Leif

2011-01-01

The paper at hand presents the initial investigations on the development and fabrication of a micro thruster based on LTCC technology, delivering a thrust in the micro Newton regime. Using smaller segments of an observation system distributed on two or more spacecrafts, one can realize an observa...

Ash transformation during co-firing coal and straw

DEFF Research Database (Denmark)

Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

2007-01-01

Co-firing straw with coal in pulverized fuel boilers can cause problems related to fly ash utilization, deposit formation, corrosion and SCR catalyst deactivation due to the high contents of Cl and K in the ash. To investigate the interaction between coal and straw ash and the effect of coal...... quality on fly ash and deposit properties, straw was co-fired with three kinds of coal in an entrained flow reactor. The compositions of the produced ashes were compared to the available literature data to find suitable scaling parameters that can be used to predict the composition of ash from straw...... and coal co-firing. Reasonable agreement in fly ash compositions regarding total K and fraction of water soluble K was obtained between co-firing in an entrained flow reactor and full-scale plants. Capture of potassium and subsequent release of HCl can be achieved by sulphation with SO2 and more...

Investigation of a zirconia co-fired ceramic calorimetric microsensor for high-temperature flow measurements

International Nuclear Information System (INIS)

Lekholm, Ville; Persson, Anders; Klintberg, Lena; Thornell, Greger

2015-01-01

This paper describes the design, fabrication and characterization of a flow sensor for high-temperature, or otherwise aggressive, environments, like, e.g. the propulsion system of a small spacecraft. The sensor was fabricated using 8 mol% yttria stabilized zirconia (YSZ8) high-temperature co-fired ceramic (HTCC) tape and screen printed platinum paste. A calorimetric flow sensor design was used, with five 80 µm wide conductors, separated by 160 µm, in a 0.4 mm wide, 0.1 mm deep and 12.5 mm long flow channel. The central conductor was used as a heater for the sensor, and the two adjacent conductors were used to resistively measure the heat transferred from the heater by forced convection. The two outermost conductors were used to study the influence of an auxiliary heat source on the sensor. The resistances of the sensor conductors were measured using four-point connections, as the gas flow rate was slowly increased from 0 to 40 sccm, with different power supplied through the central heater, as well as with an upstream or downstream heater powered. In this study, the thermal and electrical integrability of microcomponents on the YSZ8 substrate was of particular interest and, hence, the influence of thermal and ionic conduction in the substrate was studied in detail. The effect of the ion conductivity of YSZ8 was studied by measuring the resistance of a platinum conductor and the resistance between two adjacent conductors on YSZ8, in a furnace at temperatures from 20 to 930 °C and by measuring the resistance with increasing current through a conductor. With this design, the influence of ion conductivity through the substrate became apparent above 700 °C. The sensitivity of the sensor was up to 1 mΩ sccm −1 in a range of 0–10 sccm. The results show that the signal from the sensor is influenced by the integrated auxiliary heating conductors and that these auxiliary heaters provide a way to balance disturbing heat sources, e.g. thrusters or other

Effects of firing temperature on the properties of ceramics produced from a clay tailings

International Nuclear Information System (INIS)

Oliveira, V.M.C.A.; Vidal, A.B.; Ribeiro, S.

2012-01-01

The aim of this study was to evaluate the properties of ceramics produced by the firing of a tailing from a clay mining of quartz sand for their application in construction, primarily in the floors and walls. The waste was pressed and the compacts were fired at 1000, 1100, 1200, 1300, 1400 and 1500°C. The results showed linear shrinkage (RL) and water absorption (AA) ranging from 0.5 to 6.5% and 16.4 to 0.5%, respectively. It was also decreased porosity and bulk density increased with increasing treatment temperature. In the analyzes of fracture was observed increase cohesion between particles and connections of the reduction in porosity with increasing firing temperature. The sample showed a better set of mechanical properties of the sample was fired at 1300°C, and present the best appearance. (author)

Impedance spectroscopy of Li2CO3 doped (Ba,Sr)TiO3 ceramic

Science.gov (United States)

Ham, Yong-Su; Koh, Jung-Hyuk

2013-02-01

(BaxSr1-x)TiO3-based ceramic has been considered as one of the most important electronic materials widely employed in microwave passive device applications. Many researches have been performed to lower the high sintering temperature, by adding various dopants such as B2O3, La2O3, etc. In our previous study, by adding Li2CO3 to (Ba0.5,Sr0.5)TiO3 ceramics, the sintering temperature of Li2CO3 doped (Ba0.5,Sr0.5)TiO3 ceramics decreased from 1350 to 900 °C. This study observed the crystalline structure and electrical properties of Li2CO3 doped (Ba0.5,Sr0.5)TiO3 ceramics. In scanning the crystalline structure of Li2CO3 doped (Ba0.5,Sr0.5)TiO3 ceramics, no pyro phase was observed by X-ray diffraction analysis. To investigate the electrical properties of Li2CO3 doped (Ba0.5,Sr0.5)TiO3 ceramics, real and imaginary parts of the impedances were analyzed. Complex impedance data were measured from 100 Hz to 1 MHz at various temperature ranges.

AFFORDABLE MULTI-LAYER CERAMIC (MLC) MANUFACTURING FOR POWER SYSTEMS (AMPS)

Energy Technology Data Exchange (ETDEWEB)

E.A. Barringer, Ph.D.

2002-11-27

McDermott Technology, Inc. (MTI) is attempting to develop high-performance, cost-competitive solid oxide fuel cell (SOFC) power systems. Recognizing the challenges and limitations facing the development of SOFC stacks comprised of electrode-supported cells and metallic interconnects, McDermott Technology, Inc. (MTI) has chosen to pursue an alternate path to commercialization. MTI is developing a multi-layer, co-fired, planar SOFC stack that will provide superior performance and reliability at reduced costs relative to competing designs. The MTI approach combines state-of-the-art SOFC materials with the manufacturing technology and infrastructure established for multi-layer ceramic (MLC) packages for the microelectronics industry. The rationale for using MLC packaging technology is that high quality, low-cost manufacturing has been demonstrated at high volumes. With the proper selection of SOFC materials, implementation of MLC fabrication methods offers unique designs for stacks (cells and interconnects) that are not possible through traditional fabrication methods. The MTI approach eliminates use of metal interconnects and ceramic-metal seals, which are primary sources of stack performance degradation. Co-fired cells are less susceptible to thermal cycling stresses by using material compositions that have closely matched coefficients of thermal expansion between the cell and the interconnect. The development of this SOFC stack technology was initiated in October 1999 under the DOE cosponsored program entitled ''Affordable Multi-layer Ceramic Manufacturing for Power Systems (AMPS)''. The AMPS Program was conducted as a two-phase program: Phase I--Feasibility Assessment (10/99--9/00); and Phase II--Process Development for Co-fired Stacks (10/00-3/02). This report provides a summary of the results from Phase I and a more detailed review of the results for Phase II. Phase I demonstrated the feasibility for fabricating multi-layer, co-fired cells and

A Ferrite LTCC-Based Monolithic SIW Phased Antenna Array

KAUST Repository

Nafe, Ahmed A.; Ghaffar, Farhan A.; Farooqui, Muhammad Fahad; Shamim, Atif

2016-01-01

In this work, we present a novel configuration for realizing monolithic SIW-based phased antenna arrays using Ferrite LTCC technology. Unlike the current common schemes for realizing SIW phased arrays that rely on surface-mount component (p-i-n diodes, etc) for controlling the phase of the individual antenna elements, here the phase is tuned by biasing of the ferrite filling of the SIW. This approach eliminates the need for mounting of any additional RF components and enables seamless monolithic integration of phase shifters and antennas in SIW technology. As a proof of concept, a two-element slotted SIW-based phased array is designed, fabricated and measured. The prototype exhibits a gain of 4.9 dBi at 13.2 GHz and a maximum E-plane beam-scanning of 28 degrees using external windings for biasing the phase shifters. Moreover, the array can achieve a maximum beam-scanning of 19 degrees when biased with small windings that are embedded in the package. This demonstration marks the first time a fully monolithic SIW-based phased array is realized in Ferrite LTCC technology and paves the way for future larger-size implementations.

A Ferrite LTCC-Based Monolithic SIW Phased Antenna Array

KAUST Repository

Nafe, Ahmed

2016-11-17

In this work, we present a novel configuration for realizing monolithic SIW-based phased antenna arrays using Ferrite LTCC technology. Unlike the current common schemes for realizing SIW phased arrays that rely on surface-mount component (p-i-n diodes, etc) for controlling the phase of the individual antenna elements, here the phase is tuned by biasing of the ferrite filling of the SIW. This approach eliminates the need for mounting of any additional RF components and enables seamless monolithic integration of phase shifters and antennas in SIW technology. As a proof of concept, a two-element slotted SIW-based phased array is designed, fabricated and measured. The prototype exhibits a gain of 4.9 dBi at 13.2 GHz and a maximum E-plane beam-scanning of 28 degrees using external windings for biasing the phase shifters. Moreover, the array can achieve a maximum beam-scanning of 19 degrees when biased with small windings that are embedded in the package. This demonstration marks the first time a fully monolithic SIW-based phased array is realized in Ferrite LTCC technology and paves the way for future larger-size implementations.

A self-biased 3D tunable helical antenna in ferrite LTCC substrate

KAUST Repository

Ghaffar, Farhan A.; Shamim, Atif

2015-01-01

A ferrite LTCC based helical antenna which also provides magneto-static bias for its frequency tuning is presented in this work. The 3D helical-cum-bias winding design avoids the use of large external electromagnets which are traditionally used with ferrite based tunable antennas. This reduces the overall size of the design while making it efficient by getting rid of demagnetization effect experienced at the air-to-ferrite interface. RF choke and DC blocking capacitor, required to isolate the RF and DC passing through a single structure, are integrated within the multi-layer Ferrite LTCC substrate. Magnetostatic and microwave simulations have been carried out for the design optimization. The prototype antenna demonstrates a tuning range of 10 % around 13 GHz. An optimized design with an air cavity is also presented which reduces the biasing power requirement by 40 %.

A self-biased 3D tunable helical antenna in ferrite LTCC substrate

KAUST Repository

Ghaffar, Farhan A.

2015-07-19

A ferrite LTCC based helical antenna which also provides magneto-static bias for its frequency tuning is presented in this work. The 3D helical-cum-bias winding design avoids the use of large external electromagnets which are traditionally used with ferrite based tunable antennas. This reduces the overall size of the design while making it efficient by getting rid of demagnetization effect experienced at the air-to-ferrite interface. RF choke and DC blocking capacitor, required to isolate the RF and DC passing through a single structure, are integrated within the multi-layer Ferrite LTCC substrate. Magnetostatic and microwave simulations have been carried out for the design optimization. The prototype antenna demonstrates a tuning range of 10 % around 13 GHz. An optimized design with an air cavity is also presented which reduces the biasing power requirement by 40 %.

Process simulation of co-firing torrefied biomass in a 220 MWe coal-fired power plant

International Nuclear Information System (INIS)

Li, Jun; Zhang, Xiaolei; Pawlak-Kruczek, Halina; Yang, Weihong; Kruczek, Pawel; Blasiak, Wlodzimierz

2014-01-01

Highlights: • The performances of torrefaction based co-firing power plant are simulated by using Aspen Plus. • Mass loss properties and released gaseous components have been studied during biomass torrefaction processes. • Mole fractions of CO 2 and CO account for 69–91% and 4–27% in total torrefied gases. • The electrical efficiency reduced when increasing either torrefaction temperature or substitution ratio of biomass. - Abstract: Torrefaction based co-firing in a pulverized coal boiler has been proposed for large percentage of biomass co-firing. A 220 MWe pulverized coal-power plant is simulated using Aspen Plus for full understanding the impacts of an additional torrefaction unit on the efficiency of the whole power plant, the studied process includes biomass drying, biomass torrefaction, mill systems, biomass/coal devolatilization and combustion, heat exchanges and power generation. Palm kernel shells (PKS) were torrefied at same residence time but 4 different temperatures, to prepare 4 torrefied biomasses with different degrees of torrefaction. During biomass torrefaction processes, the mass loss properties and released gaseous components have been studied. In addition, process simulations at varying torrefaction degrees and biomass co-firing ratios have been carried out to understand the properties of CO 2 emission and electricity efficiency in the studied torrefaction based co-firing power plant. According to the experimental results, the mole fractions of CO 2 and CO account for 69–91% and 4–27% in torrefied gases. The predicted results also showed that the electrical efficiency reduced when increasing either torrefaction temperature or substitution ratio of biomass. A deep torrefaction may not be recommended, because the power saved from biomass grinding is less than the heat consumed by the extra torrefaction process, depending on the heat sources

Theory and design of a half-mode SIW Ferrite LTCC phase shifter

KAUST Repository

Ghaffar, Farhan A.; Shamim, Atif

2015-01-01

A half mode SIW based Ferrite LTCC phase shifter is presented in this work. A theoretical model to predict the phase shift in the partially magnetized state has been derived. Contrary to the bulky external magnets employed by conventional ferrite

Deforestation fires versus understory fires in the Amazon Basin: What can we learn from satellite-based CO measurements?

Science.gov (United States)

Martinez-Alonso, S.; Deeter, M. N.; Worden, H. M.; Gille, J. C.; Clerbaux, C.; George, M.

2014-12-01

Deforestation fires in the Amazon Basin abound during the dry season (July to October) and are mostly associated with "slash and burn" agricultural practices. Understory fires occur when fires escape from deforested areas into neighboring standing forests; they spread slowly below the canopy, affecting areas that may be comparable or even larger than clear-cut areas. The interannual variabilities of understory fires and deforestation rates appear to be uncorrelated. Areas burned in understory fires are particularly extensive during droughts. Because they progress below a canopy of living trees, understory fires and their effects are not as easily identifiable from space as deforestation fires. Here we analyze satellite remote sensing products for CO and fire to investigate differences between deforestation fires and understory fires in the Amazon Basin under varying climatic conditions. The MOPITT (Measurements Of Pollution In The Troposphere) instrument on board NASA's Terra satellite has been measuring tropospheric CO since 2000, providing the longest global CO record to date. IASI (the Infrared Atmospheric Sounding Interferometer) A and B are two instruments on board METOP-A and -B, respectively, measuring, among others, CO since 2006 and 2012. MODIS (the Moderate Resolution Imaging Spectroradiometer) instruments on board NASA's Terra and Aqua satellites provide, among other products, a daily record of fires and their effects since 2000 and 2002, respectively. The temporal extent of all these datasets allows for the detailed analysis of drought versus non-drought years. Initial results indicate that MOPITT CO emissions during the dry season peaked in 2005, 2007, and 2010. Those were draught years and coincide with peaks in area affected by understory fires.

Biomass for electricity in the EU-27: Potential demand, CO2 abatements and breakeven prices for co-firing

International Nuclear Information System (INIS)

Bertrand, Vincent; Dequiedt, Benjamin; Le Cadre, Elodie

2014-01-01

This paper analyses the potential of biomass-based electricity in the EU-27 countries, and interactions with climate policy and the EU ETS. We estimate the potential biomass demand from the existing power plants, and we match our estimates with the potential biomass supply in Europe. Furthermore, we compute the CO2 abatement associated with the co-firing opportunities in European coal plants. We find that the biomass demand from the power sector may be very high compared with potential supply. We also identify that co-firing can produce high volumes of CO 2 abatements, which may be two times larger than that of the coal-to-gas fuel switching. We also compute biomass and CO2 breakeven prices for co-firing. Results indicate that biomass-based electricity remains profitable with high biomass prices, when the carbon price is high: a Euros 16–24 (25–35, respectively) biomass price (per MWh prim ) for a Euros 20 (50, respectively) carbon price. Hence, the carbon price appears as an important driver, which can make profitable a high share of the potential biomass demand from the power sector, even with high biomass prices. This aims to gain insights on how biomass market may be impacted by the EU ETS and others climate policies. - Highlights: • Technical potential of biomass (demand and CO 2 abatement) in European electricity. • Calculation for co-firing and biomass power plants; comparison with potential biomass supply in EU-27 countries. • Calculation of biomass and CO 2 breakeven prices for co-firing. • Potential demand is 8–148% of potential supply (up to 80% of demand from co-firing). • High potential abatement from co-firing (up to 365 Mt/yr); Profitable co-firing with €16-24 (25–35) biomass price for €20 (50) CO 2 price

Ultra-Low Carbon Emissions from Coal-Fired Power Plants through Bio-Oil Co-Firing and Biochar Sequestration.

Science.gov (United States)

Dang, Qi; Mba Wright, Mark; Brown, Robert C

2015-12-15

This study investigates a novel strategy of reducing carbon emissions from coal-fired power plants through co-firing bio-oil and sequestering biochar in agricultural lands. The heavy end fraction of bio-oil recovered from corn stover fast pyrolysis is blended and co-fired with bituminous coal to form a bio-oil co-firing fuel (BCF). Life-cycle greenhouse gas (GHG) emissions per kWh electricity produced vary from 1.02 to 0.26 kg CO2-eq among different cases, with BCF heavy end fractions ranging from 10% to 60%, which corresponds to a GHG emissions reduction of 2.9% to 74.9% compared with that from traditional bituminous coal power plants. We found a heavy end fraction between 34.8% and 37.3% is required to meet the Clean Power Plan's emission regulation for new coal-fired power plants. The minimum electricity selling prices are predicted to increase from 8.8 to 14.9 cents/kWh, with heavy end fractions ranging from 30% to 60%. A minimum carbon price of $67.4 ± 13 per metric ton of CO2-eq was estimated to make BCF power commercially viable for the base case. These results suggest that BCF co-firing is an attractive pathway for clean power generation in existing power plants with a potential for significant reductions in carbon emissions.

Gain Enhanced LTCC System-on-Package for UMRR Applications

KAUST Repository

Shamim, Atif; Ghaffar, Farhan Abdul; Khalid, Muhammad Umair; Salama, Khaled N.

2014-01-01

An apparatus, system, and method for Gain Enhanced LTCC System-on-Package radar sensor. The sensor includes a substrate and an integrated circuit coupled to the substrate, where the integrated circuit is configured to transmit and receive radio frequency (RF) signals. An antenna may be coupled to the integrated circuit and a lens may be coupled to the antenna. The lens may be configured to enhance the gain of the sensor.

Gain Enhanced LTCC System-on-Package for UMRR Applications

KAUST Repository

Shamim, Atif

2014-10-14

An apparatus, system, and method for Gain Enhanced LTCC System-on-Package radar sensor. The sensor includes a substrate and an integrated circuit coupled to the substrate, where the integrated circuit is configured to transmit and receive radio frequency (RF) signals. An antenna may be coupled to the integrated circuit and a lens may be coupled to the antenna. The lens may be configured to enhance the gain of the sensor.

Low-sintering condenser materials on the basis of barium titanate; Niedrig-sinternde Kondensatorwerkstoffe auf der Basis von Bariumtitanat

Energy Technology Data Exchange (ETDEWEB)

Naghib zadeh, Hamid

2010-07-01

the laminates after sintering. The results of the temperature stability of the dielectric constant in powder compacts could be reproduced in multilayer capacitors. Due to very low capacity changes in the frequency range between 1 kHz and 1 MHz all five capacitor materials are applicable at this frequency range. Furthermore the capacitor tapes exhibit high breakdown strength significantly above 20 kV / mm (except one sample). To reach a defect free co-firing of sandwiched LTCC laminates consisting of capacitor tapes and standard low dielectric constant tapes the shrinkage behaviour and the coefficient of thermal expansion of two components were matched. The embedded capacitor tapes into standard low dielectric constant tapes can be sufficiently densified during co-firing process at 900 C and the dielectric properties are comparable with those of separate sintered capacitor tapes. The co-firing of multi-component LTCC laminates consisting of ferritic tapes, low dielectric constant tapes and capacitor tapes with different shrinkage curves was also investigated. It was found that the manufacturing of such a multi-component module is only possible when a uniaxial pressure (1.5 MPa) is carried out during co-firing. However, because of the difference in the coefficient of thermal expansion of different components, a quite defectfree multi-component module could not be manufactured but by stacking the tapes in the correct order defects like cracks can be strongly minimized. For this purpose the capacitor tapes that have larger coefficient of thermal expansion must be inserted in the middle of the multi-component laminates. The results obtained in this work are very useful for the integration of passive components into compacted LTCC module and the further miniaturization of electronic devices based on ceramic multilayer. The new low fired high dielectric constant materials can be used both as ceramic tapes and as screen-printable pastes for integration of capacitors into LTCC

Low-Temperature Co-Fired Unipoled Multilayer Piezoelectric Transformers.

Science.gov (United States)

Gao, Xiangyu; Yan, Yongke; Carazo, Alfredo Vazquez; Dong, Shuxiang; Priya, Shashank

2018-03-01

The reliability of piezoelectric transformers (PTs) is dependent upon the quality of fabrication technique as any heterogeneity, prestress, or misalignment can lead to spurious response. In this paper, unipoled multilayer PTs were investigated focusing on high-power composition and co-firing profile in order to provide low-temperature synthesized high-quality device measured in terms of efficiency and power density. The addition of 0.2 wt% CuO into Pb 0.98 Sr 0.02 (Mg 1/3 Nb 2/3 ) 0.06 (Mn 1/3 Nb 2/3 ) 0.06 (Zr 0.48 Ti 0.52 ) 0.88 O 3 (PMMnN-PZT) reduces the co-firing temperature from 1240 °C to 930 °C, which allows the use of Ag/Pd inner electrode instead of noble Pt inner electrode. Low-temperature synthesized material was found to exhibit excellent piezoelectric properties ( , , %, pC/N, and °C). The performance of the PT co-fired with Ag/Pd electrode at 930 °C was similar to that co-fired at 1240 °C with Pt electrode (25% reduction in sintering temperature). Both high- and low-temperature synthesized PTs demonstrated 5-W output power with >90% efficiency and 11.5 W/cm 3 power density.

Synthetic flux as a whitening agent for ceramic tiles

Energy Technology Data Exchange (ETDEWEB)

Rodrigues dos Santos, Geocris, E-mail: geocris.rodrigues@gmail.com [INNOVARE Inteligência Em Cerâmica, 13566-420 São Carlos, SP (Brazil); Departamento De Engenharia Dos Materiais, Universidade Federal De São Carlos, 13565-905 São Carlos, SP (Brazil); Salvetti, Alfredo Roque [Departamento De Física, Universidade Federal De Mato Grosso Do Sul (Brazil); Cabrelon, Marcelo Dezena [INNOVARE Inteligência Em Cerâmica, 13566-420 São Carlos, SP (Brazil); Departamento De Engenharia Dos Materiais, Universidade Federal De São Carlos, 13565-905 São Carlos, SP (Brazil); Morelli, Márcio Raymundo [Departamento De Engenharia Dos Materiais, Universidade Federal De São Carlos, 13565-905 São Carlos, SP (Brazil)

2014-12-05

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 (Fe{sub 2}O{sub 3}) 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.

[Research progress in CoCr metal-ceramic alloy fabricated by selective laser melting].

Science.gov (United States)

Yan, X; Lin, H

2018-02-09

Cobalt-chromium alloys have been applied to dental porcelain fused to metal (PFM) restorations over the past decades owing to their excellent corrosion resistance, good biocompatibility and low price. The production of CoCr metal-ceramic restorations has always been based on traditional lost-wax casting techniques. However, in recent years, selective laser melting (SLM) is becoming more and more highly valued by dental laboratories and dental practitioners due to its individuation, precision and efficiency. This paper mainly reviews the recent researches on the production process of copings, microstructure, mechanical property, metal-ceramic bond strength, fit of copings, corrosion resistance and biocompatibility of SLM CoCr metal-ceramic alloy.

A Passive Pressure Sensor Fabricated by Post-Fire Metallization on Zirconia Ceramic for High-Temperature Applications

Directory of Open Access Journals (Sweden)

Tao Luo

2014-09-01

Full Text Available A high-temperature pressure sensor realized by the post-fire metallization on zirconia ceramic is presented. The pressure signal can be read out wirelessly through the magnetic coupling between the reader antenna and the sensor due to that the sensor is equivalent to an inductive-capacitive (LC resonance circuit which has a pressure-sensitive resonance frequency. Considering the excellent mechanical properties in high-temperature environment, multilayered zirconia ceramic tapes were used to fabricate the pressure-sensitive structure. Owing to its low resistivity, sliver paste was chosen to form the electrical circuit via post-fire metallization, thereby enhancing the quality factor compared to sensors fabricated by cofiring with a high-melting-point metal such as platinum, tungsten or manganese. The design, fabrication, and experiments are demonstrated and discussed in detail. Experimental results showed that the sensor can operate at 600 °C with quite good coupling. Furthermore, the average sensitivity is as high as 790 kHz/bar within the measurement range between 0 and 1 Bar.

Committed CO2 Emissions of China's Coal-fired Power Plants

Science.gov (United States)

Suqin, J.

2016-12-01

The extent of global warming is determined by the cumulative effects of CO2 in the atmosphere. Coal-fired power plants, the largest anthropogenic source of CO2 emissions, produce large amount of CO2 emissions during their lifetimes of operation (committed emissions), which thus influence the future carbon emission space under specific targets on mitigating climate change (e.g., the 2 degree warming limit relative to pre-industrial levels). Comprehensive understanding of committed CO2 emissions for coal-fired power generators is urgently needed in mitigating global climate change, especially in China, the largest global CO2emitter. We calculated China's committed CO2 emissions from coal-fired power generators installed during 1993-2013 and evaluated their impact on future emission spaces at the provincial level, by using local specific data on the newly installed capacities. The committed CO2 emissions are calculated as the product of the annual coal consumption from newly installed capacities, emission factors (CO2emissions per unit crude coal consumption) and expected lifetimes. The sensitivities about generators lifetimes and the drivers on provincial committed emissions are also analyzed. Our results show that these relatively recently installed coal-fired power generators will lead to 106 Gt of CO2 emissions over the course of their lifetimes, which is more than three times the global CO2 emissions from fossil fuels in 2010. More than 80% (85 Gt) of their total committed CO2 will be emitted after 2013, which are referred to as the remaining emissions. Due to the uncertainties of generators lifetime, these remaining emissions would increase by 45 Gt if the lifetimes of China's coal-fired power generators were prolonged by 15 years. Furthermore, the remaining emissions are very different among various provinces owing to local developments and policy disparities. Provinces with large amounts of secondary industry and abundant coal reserves have higher committed

Low-temperature sintering and microwave dielectric properties of Al2TeO6–TeO2 ceramics

International Nuclear Information System (INIS)

Kagomiya, Isao; Kodama, Yuichiro; Shimizu, Yukihiro; Kakimoto, Ken-ichi; Ohsato, Hitoshi; Miyauchi, Yasuharu

2015-01-01

Highlights: • This is the first study of dielectric properties of Al 2 TeO 6 –TeO 2 sintered at 900 °C. • The sintering at 900 °C contributed to densification, but it causes TeO 2 evaporation. • The annealing at 750 °C was effective for the further densification. • The both ε r and Q · f in the Al 2 TeO 6 –TeO 2 were improved with the annealing. - Abstract: We propose Al 2 TeO 6 –TeO 2 ceramics as a candidate for use as low-temperature co-fired ceramics (LTCC). We investigated microwave dielectric properties and low-temperature sintering conditions for Al 2 TeO 6 –TeO 2 ceramics. The calcined Al 2 TeO 6 powders were sintered at 900 °C for 2–10 h with 30–50 wt% additive TeO 2 . X-ray powder diffraction patterns showed that the sintered samples were Al 2 TeO 6 –TeO 2 composite with no other phase. The apparent density was improved with the additive TeO 2 content of up to 45 wt%. The dielectric constant (ε r ) increased by adding TeO 2 content from 35 to 45 wt%, although the quality factor (Q · f) decreased. During sintering at 900 °C, the ε r of the Al 2 TeO 6 –TeO 2 decreased slightly, whereas the Q · f increased gradually. The observed microstructures showed that the longer sintering time makes fewer pores in Al 2 TeO 6 –TeO 2 ceramics. Sintering at 900 °C for a long time contributes to densification, but it simultaneously causes TeO 2 evaporation. To prevent TeO 2 evaporation, we investigated the effects of annealing at 750 °C after sintering at 900 °C. Apparent densities or ε r for the annealed samples were higher than those of the non-annealed samples. The Q · f improved with increasing annealing duration time, suggesting that sintering proceeded well during annealing with slower TeO 2 evaporation at 750 °C. The results show that annealing at 750 °C is effective to facilitate sintering and to control TeO 2 evaporation

Characterization of Al2O3-Co ceramic composite obtained by high energy mill

International Nuclear Information System (INIS)

Souza, J.L.; Assis, R.B. de; Carlos, E.M.; Oliveira, T.P.; Costa, F.A. da

2014-01-01

This work aims to characterize the ceramic composite Al 2 O3-Co obtained by high energy grinding. The composites were obtained by milling Al 2 O 3 and Co in a high energy mill at a speed of 400 rpm, in proportions of 5 to 20% Cobalt (Co). Ceramic composites with 5 and 20% cobalt were sintered at 1200 and 1300 ° C, with a 60-minute plateau and a heating rate of 10 ° C / min. The samples were characterized by X-ray diffraction (XRD), thermogravimetry and differential scanning calorimetry (TG / DSC) and scanning electron microscopy (SEM). The results show the significant effect of cobalt percentage and high energy grinding on the final properties of the Al 2 O 3 - Co ceramic composite, presenting satisfactory values for the composite with a 20% cobalt percentage, showing to be a promising material for application in cutting tools

Modeling the Emission of CO from Wood Fires using Detailed Chemical Kinetics

DEFF Research Database (Denmark)

Dederichs, Anne

Carbon monoxide is treated as one of the most common and dangerous of gases evolving in fires. Modeling the formation of the toxic gas CO from in fire enclosures using detailed chemical kinetics is the topic of this manuscript. A semi-empirical model is developed to study the formation of CO from......, the model separately treats the process of pyrolysis and combustion. For under ventilated conditions and at high temperatures during pyrolysis it is found that the process of pyrolysation strongly influences the formation of CO in fire. CO2 follows the same trend....

Fracture Toughness of Ceramics Fired at Different Temperatures

Directory of Open Access Journals (Sweden)

Peter SIN

2012-03-01

Full Text Available The fracture toughness test was performed at room temperature on sets of 5 ceramic samples made from material for high voltage insulators (kaolin 36 wt. %, Al2O3 30 wt. %, clay 12 wt. % and feldspar 22 wt. % fired at temperatures 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1250, 1300, 1400, 1500 °C at heating and cooling rate of 5 °C/min. The precrack was made to each sample by indentation under the loads 10 N – 200 N, the dwell time was 45 s and the loading rate was 10 N/s. Results of the fracture toughness tests were in accordance with changes of structure of the samples after the partial firings. Fracture toughness from 20 °C to 500 °C is almost constant and it varies between 0.1 MPa·m0.5and 0.2 MPa·m0.5. Dehydroxylation (420 °C – 600 °C does not influence the value of fracture toughness. At temperature interval where we assume sintering (700 °C – 1250 °C we observe exponential dependence of fracture toughness up to 1.5 MPa·m0.5. From comparison of the fracture toughness, Young’s modulus and flexural strength follows a correlation and proporcionality of these mechanical properties.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1349

46 CFR 35.40-10 - Steam, foam, or CO2 fire smothering apparatus-TB/ALL.

Science.gov (United States)

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Steam, foam, or CO2 fire smothering apparatus-TB/ALL. 35... Posting and Marking Requirements-TB/ALL. § 35.40-10 Steam, foam, or CO2 fire smothering apparatus—TB/ALL. Steam, foam, or CO2 fire smothering apparatus shall be marked “STEAM FIRE APPARATUS” or “FOAM FIRE...

Enhanced Luminescent Properties in Tm3+/Dy3+ Co-doped Transparent Phosphate Glass Ceramic

OpenAIRE

Yao L. Q.; Chen G. H.; Zhong H. J.; Cui S. C.; Li F.; Gan J.Y.

2016-01-01

Novel Tm3+/Dy3+ co-doped phosphate glass and glass ceramic samples for white light emitting diodes were prepared by melt quenching method. Under 353 nm excitation, the colors of the luminescence of the glass and glass ceramic samples are white. The CIE chromaticity coordinates (0.338, 0.328) of the emission from the glass ceramic is close to the standard white-light illumination (0.333, 0.333). Compared to the glass, the fluorescence intensity in the glass ceramic is greatly enhanced.

The feasibility of co-firing biomass for electricity in Missouri

International Nuclear Information System (INIS)

Liu, Zuoming; Altman, Ira; Johnson, Thomas G.

2014-01-01

Bioenergy is one of the most significant energy resources with potential to serve as a partial replacement for fossil. As an agricultural state, Missouri has great potential to use biomass for energy production. In 2008, Missouri adopted a renewable portfolio standard (RPS) yet about 80% of its power supply still comes from coal. This paper describes a feasibility study of co-firing biomass in existing coal-powered plants in Missouri. Specifically, this study developed a linear programming model and simulated six scenarios to assess the economic feasibility and greenhouse gas impacts of co-firing biomass in existing qualified coal power plants in Missouri. The results of this study indicate that although co-firing can reduce the emissions of GHG and environmental pollutants, it is still not an economically feasible option for power generation without additional economic or policy incentives or regulations which could take environmental costs into account. Based on these results, strategies and policies to promote the utilization of biomass and to increase its competitiveness with fossil fuels are identified and discussed. - Highlights: • This paper reports on a study of the economic feasibility and environmental effects of co-firing biomass for electricity. • The feasibility of co-firing biomass varies by location depending on local availability of biomass and size of facility. • We apply a linear optimization model that generates economic and environmental indicators for each of several locations. • This paper will appeal to power generators, academic researchers and consultants interested in the feasibility of biopower

Long term deactivation test of high dust SCR catalysts by straw co-firing

Energy Technology Data Exchange (ETDEWEB)

Weigang Lin; Degn Jensen, A.; Bjerkvig, J.

2009-12-15

The consequences of carbon dioxide induced global warming cause major concern worldwide. The consumption of energy produced with fossil fuels is the major factor that contributes to the global warming. Biomass is a renewable energy resource and has a nature of CO{sub 2} neutrality. Co-combustion of biomass in existing coal fired power plants can maintain high efficiency and reduce the emission of CO{sub 2} at same time. However, one of the problems faced by co-firing is deactivation of the SCR catalysts. Understanding of the mechanisms of deactivation of the catalyst elements at co-firing conditions is crucial for long term runs of the power plants. Twenty six SCR catalyst elements were exposed at two units (SSV3 and SSV4) in the Studstrup Power Plant for a long period. Both units co-fire coal and straw with a typical fraction of 8-10% straw on an energy basis during co-firing. SSV4 unit operated in co-firing mode most of the time; SSV3 unit co-fired straw half of the operating time. The main objective of this PSO-project is to gain knowledge of a long term influence on catalyst activity when co-firing straw in coal-fired power plants, thus, to improve the basis for operating the SCR-plants for NO{sub x}-reduction. The exposure time of the applied catalyst elements (HTAS and BASF) varied from approximately 5000 to 19000 hours in the power plant by exchanging the element two times. The activity of all elements was measured before and after exposure in a bench scale test rig at the Department of Chemical and Biochemical Engineering, Technical University of Denmark. The results show that the activity, estimated by exclusion of channel clogging of the elements, decreases gradually with the total exposure time. It appears that the exposure time under co-firing condition has little effect on the deactivation of the catalyst elements and no sharp decrease of the activity was observed. The average deactivation rate of the catalyst elements is 1.6 %/1000 hours. SEM

Use of numerical modeling in design for co-firing biomass in wall-fired burners

DEFF Research Database (Denmark)

Yin, Chungen; Rosendahl, Lasse Aistrup; Kær, Søren Knudsen

2004-01-01

modification to the motion and reaction due to their non-sphericity. The simulation results show a big difference between the two cases and indicate it is very significant to take into account the non-sphericity of biomass particles in order to model biomass combustion more accurately. Methods to improve...... of numerical modeling. The models currently used to predict solid fuel combustion rely on a spherical particle shape assumption, which may deviate a lot from reality for big biomass particles. A sphere gives a minimum in terms of the surface-area-to-volume ratio, which impacts significantly both motion...... and reaction of a particle. To better understand biomass combustion and thus improve the design for co-firing biomass in wall-fired burners, non-sphericity of biomass particles is considered. To ease comparison, two cases are numerically studied in a 10m long gas/biomass co-fired burner model. (1) The biomass...

Technical, economic and environmental potential of co-firing of biomass in coal and natural gas fired power plants in the Netherlands

International Nuclear Information System (INIS)

Van Ree, R.; Korbee, R.; Eenkhoorn, S.; De Lange, T.; Groenendaal, B.

2000-01-01

In this paper the technical, economic, and environmental potential of co-firing of biomass in existing Dutch coal and natural gas fired power plants, and industrial combined-cycles (CC), is addressed. Main criteria that are considered are: the availability and contractibility of biomass for energy purposes; the (technical) operation of the conventional fossil fuel based processes may not be disturbed; the gaseous and liquid plant emissions have to comply to those applicable for power plants/CCs, the commercial applicability of the solid residues may not be negatively influenced; applicable additional biomass conversion technologies must be commercially available; the necessary additional investment costs must be acceptable from an economic point of view, and the co-firing option must result in a substantial CO 2 -emission reduction. The main result of the study described in the paper is the presentation of a clear and founded indication of the total co-firing potential of biomass in existing power plants and industrial CCs in the Netherlands. This potential is determined by considering both technical, economic, and environmental criteria. In spite of the fact that the co-firing potential for the specific Dutch situation is presented, the results of the criteria considered are more generally applicable, and therefore are also very interesting for potential co-firing initiatives outside of the Netherlands

Ash transformation in suspension fired boilers co-firing coal and straw

DEFF Research Database (Denmark)

Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

The properties of the ash from co-firing of coal and straw have a large influence on boiler operation, flue gas cleaning equipment and appropriate utilization of the fly ash. A study on the fuel composition and local conditions influence on fly ash properties has been done by making entrained flo...

An ensemble approach to simulate CO2 emissions from natural fires

Science.gov (United States)

Eliseev, A. V.; Mokhov, I. I.; Chernokulsky, A. V.

2014-06-01

This paper presents ensemble simulations with the global climate model developed at the A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS CM). These simulations are forced by historical reconstructions of concentrations of well-mixed greenhouse gases (CO2, CH4, and N2O), sulfate aerosols (both in the troposphere and stratosphere), extent of crops and pastures, and total solar irradiance for AD 850-2005 (hereafter all years are taken as being AD) and by the Representative Concentration Pathway (RCP) scenarios for the same forcing agents until the year 2300. Our model implements GlobFIRM (Global FIRe Model) as a scheme for calculating characteristics of natural fires. Comparing to the original GlobFIRM model, in our implementation, the scheme is extended by a module accounting for CO2 release from soil during fires. The novel approach of our paper is to simulate natural fires in an ensemble fashion. Different ensemble members in the present paper are constructed by varying the values of parameters of the natural fires module. These members are constrained by the GFED-3.1 data set for the burnt area and CO2 release from fires and further subjected to Bayesian averaging. Our simulations are the first coupled model assessment of future changes in gross characteristics of natural fires. In our model, the present-day (1998-2011) global area burnt due to natural fires is (2.1 ± 0.4) × 106 km2 yr-1 (ensemble mean and intra-ensemble standard deviation are presented), and the respective CO2 emissions to the atmosphere are (1.4 ± 0.2) Pg C yr-1. The latter value is in agreement with the corresponding GFED estimates. The area burnt by natural fires is generally larger than the GFED estimates except in boreal Eurasia, where it is realistic, and in Australia, where it is smaller than these estimates. Regionally, the modelled CO2 emissions are larger (smaller) than the GFED estimates in Europe (in the tropics and north-eastern Eurasia). From

Processing and properties of large-sized ceramic slabs

Energy Technology Data Exchange (ETDEWEB)

Raimondo, M.; Dondi, M.; Zanelli, C.; Guarini, G.; Gozzi, A.; Marani, F.; Fossa, L.

2010-07-01

Large-sized ceramic slabs with dimensions up to 360x120 cm{sup 2} and thickness down to 2 mm are manufactured through an innovative ceramic process, starting from porcelain stoneware formulations and involving wet ball milling, spray drying, die-less slow-rate pressing, a single stage of fast drying-firing, and finishing (trimming, assembling of ceramic-fiberglass composites). Fired and unfired industrial slabs were selected and characterized from the technological, compositional (XRF, XRD) and microstructural (SEM) viewpoints. Semi-finished products exhibit a remarkable microstructural uniformity and stability in a rather wide window of firing schedules. The phase composition and compact microstructure of fired slabs are very similar to those of porcelain stoneware tiles. The values of water absorption, bulk density, closed porosity, functional performances as well as mechanical and tribological properties conform to the top quality range of porcelain stoneware tiles. However, the large size coupled with low thickness bestow on the slab a certain degree of flexibility, which is emphasized in ceramic-fiberglass composites. These outstanding performances make the large-sized slabs suitable to be used in novel applications: building and construction (new floorings without dismantling the previous paving, ventilated facades, tunnel coverings, insulating panelling), indoor furnitures (table tops, doors), support for photovoltaic ceramic panels. (Author) 24 refs.

Processing and properties of large-sized ceramic slabs

International Nuclear Information System (INIS)

Raimondo, M.; Dondi, M.; Zanelli, C.; Guarini, G.; Gozzi, A.; Marani, F.; Fossa, L.

2010-01-01

Large-sized ceramic slabs with dimensions up to 360x120 cm 2 and thickness down to 2 mm are manufactured through an innovative ceramic process, starting from porcelain stoneware formulations and involving wet ball milling, spray drying, die-less slow-rate pressing, a single stage of fast drying-firing, and finishing (trimming, assembling of ceramic-fiberglass composites). Fired and unfired industrial slabs were selected and characterized from the technological, compositional (XRF, XRD) and microstructural (SEM) viewpoints. Semi-finished products exhibit a remarkable microstructural uniformity and stability in a rather wide window of firing schedules. The phase composition and compact microstructure of fired slabs are very similar to those of porcelain stoneware tiles. The values of water absorption, bulk density, closed porosity, functional performances as well as mechanical and tribological properties conform to the top quality range of porcelain stoneware tiles. However, the large size coupled with low thickness bestow on the slab a certain degree of flexibility, which is emphasized in ceramic-fiberglass composites. These outstanding performances make the large-sized slabs suitable to be used in novel applications: building and construction (new floorings without dismantling the previous paving, ventilated facades, tunnel coverings, insulating panelling), indoor furnitures (table tops, doors), support for photovoltaic ceramic panels. (Author) 24 refs.

Design of glass-ceramic complex microstructure with using onset point of crystallization in differential thermal analysis

International Nuclear Information System (INIS)

Hwang, Seongjin; Kim, Jinho; Shin, Hyo-Soon; Kim, Jong-Hee; Kim, Hyungsun

2008-01-01

Two types of frits with different compositions were used to develop a high strength substrate in electronic packaging using a low temperature co-fired ceramic process. In order to reveal the crystallization stage during heating to approximately 900 deg. C, a glass-ceramic consisting of the two types of frits, which had been crystallized to diopside and anorthite after firing, was tested at different mixing ratios of the frits. The exothermal peaks deconvoluted by a Gauss function in the differential thermal analysis curves were used to determine the onset point of crystallization of diopside or anorthite. The onset points of crystallization were affected by the mixing ratio of the frits, and the microstructure of the glass-ceramic depended on the onset point of crystallization. It was found that when multicrystalline phases appear in the microstructure, the resulting complex microstructure could be predicted from the onset point of crystallization obtained by differential thermal analysis

[Ceramic inlays and onlays].

Science.gov (United States)

van Pelt, A W; de Kloet, H J; van der Kuy, P

1996-11-01

Large direct composite restorations can induce shrinkage related postoperative sensitivity. Indirect resin-bonded (tooth colored) restorations may perhaps prevent these complaints. Indirect bonded ceramics are especially attractive because of their biocompatibility and esthetic performance. Several procedures and techniques are currently available for the fabrication of ceramic restorations: firing, casting, heat-pressing and milling. In this article the different systems are described. Advantages, disadvantages and clinical performance of ceramic inlays are compared and discussed.

The role of ceramic materials in the production of hydrogen with simultaneous CO{sub 2} capture

Energy Technology Data Exchange (ETDEWEB)

Barros, B.S. [Universidade Federal de Pernambuco (UFPE), PE (Brazil)

2016-07-01

Full text: Hydrogen is considered one of the most promising alternatives to fossil fuels. However, it is mainly obtained from syngas resulting from natural gas steam reforming (SMR), producing a significant amount of carbon dioxide as a side product. Carbon dioxide emission (CO2) is a major contributor to global warming, and one-third of those emissions come from fuel combustion for power generation. A new interesting process has been described to control CO2 emission: the reforming optimized by CO2 sorption, which associates conventional methane reforming and in situ capture of CO2 via absorption in a solid oxide. Furthermore, this strategy can increase the H2 production and concentrate CO2 for the eventual use as chemicals or energy vectors. Alkaline and alkaline-earth ceramics have been proposed for CO2 capture through adsorption and chemisorption processes. These materials can be classified into two large groups: dense and porous ceramics. Dense ceramics mainly trap CO2 chemically: the CO2 is chemisorbed. Among these ceramics, CaO is the most studied one. CaO-based materials have been highlighted as the solid sorbents in the capture of CO2 because of their favorable thermodynamic and chemical properties. The main problem with CaO is the strong decrease in the sorption capacity after multiple carbonation–calcination cycles. This talk will cover some strategies to improve this sorption capacity, such as the deposition of calcium oxide on an inert support, Ca12Al14O33 (mayenite). This oxide has no sorption properties but presents a large surface area, and provides stable network inhibiting deactivation of CaO by sintering. (author)

Bond strength of resin cement to CO2 and Er:YAG laser-treated zirconia ceramic

Directory of Open Access Journals (Sweden)

Shahin Kasraei

2014-11-01

Full Text Available Objectives It is difficult to achieve adhesion between resin cement and zirconia ceramics using routine surface preparation methods. The aim of this study was to evaluate the effects of CO2 and Er:YAG laser treatment on the bond strength of resin cement to zirconia ceramics. Materials and Methods In this in-vitro study 45 zirconia disks (6 mm in diameter and 2 mm in thickness were assigned to 3 groups (n = 15. In control group (CNT no laser treatment was used. In groups COL and EYL, CO2 and Er:YAG lasers were used for pretreatment of zirconia surface, respectively. Composite resin disks were cemented on zirconia disk using dual-curing resin cement. Shear bond strength tests were performed at a crosshead speed of 0.5 mm/min after 24 hr distilled water storage. Data were analyzed by one-way ANOVA and post hoc Tukey's HSD tests. Results The means and standard deviations of shear bond strength values in the EYL, COL and CNT groups were 8.65 ± 1.75, 12.12 ± 3.02, and 5.97 ± 1.14 MPa, respectively. Data showed that application of CO2 and Er:YAG lasers resulted in a significant higher shear bond strength of resin cement to zirconia ceramics (p < 0.0001. The highest bond strength was recorded in the COL group (p < 0.0001. In the CNT group all the failures were adhesive. However, in the laser groups, 80% of the failures were of the adhesive type. Conclusions Pretreatment of zirconia ceramic via CO2 and Er:YAG laser improves the bond strength of resin cement to zirconia ceramic, with higher bond strength values in the CO2 laser treated samples.

High Q ceramics in the ACe2(MoO4)4 (A = Ba, Sr and Ca) system for LTCC applications

International Nuclear Information System (INIS)

Surjith, A.; Ratheesh, R.

2013-01-01

Highlights: ► Solid state synthesis of phase pure ACe 2 (MoO 4 ) 4 (A = Ba, Sr and Ca) ceramics. ► Structural and microstructural evaluation of the synthesized ceramic materials. ► Microwave dielectric property studies of ACe 2 (MoO 4 ) 4 (A = Ba, Sr and Ca) ceramics. ► Structure-property correlation through Laser Raman studies. - Abstract: Novel low temperature sinterable high Q ceramic systems ACe 2 (MoO 4 ) 4 (A = Ba, Sr and Ca) have been prepared through solid state ceramic method. The effect of ionic radii of alkaline earth cations on the structure, microstructure and microwave dielectric properties of these ceramics were studied using powder X-ray diffraction, Laser Raman spectroscopy, scanning electron microscopy and Vector Network Analyzer. A structural change from monoclinic to tetragonal structure was observed while substituting Sr 2+ and Ca 2+ cations in place of Ba 2+ . The Sr and Ca analogues possess better microwave dielectric properties compared to BaCe 2 (MoO 4 ) 4 . All the ceramics were well sintered below 840 °C with dielectric constant in the range 10.2–12.3 together with good quality factor. The SrCe 2 (MoO 4 ) 4 ceramic exhibits an unloaded quality factor of 6762 at 8.080662 GHz with a temperature coefficient of resonant frequency of −46 ppm/°C while the CaCe 2 (MoO 4 ) 4 ceramic shows an unloaded quality factor of 7549 at 6.928868 GHz and a temperature coefficient of resonant frequency of −44 ppm/°C.

Ferrite LTCC based phased array antennas

KAUST Repository

Ghaffar, Farhan A.

2016-11-02

Two phased array antennas realized in multilayer ferrite LTCC technology are presented in this paper. The use of embedded bias windings in these designs allows the negation of external magnets which are conventionally employed with bulk ferrite medium. This reduces the required magnetostatic field strength by 90% as compared to the traditional designs. The phase shifters are implemented using the SIW technology. One of the designs is operated in the half mode waveguide topology while the other design is based on standard full mode waveguide operation. The two phase shifter designs are integrated with two element patch antenna array and slotted SIW array respectively. The array designs demonstrate a beam steering of 30° and ±19° respectively for a current excitation of 200 mA. The designs, due to their small factor can be easily integrated in modern communication systems which is not possible in the case of bulk ferrite based designs.

The effect of Co-firing with Straw and Coal on High Temperature Corrosion

DEFF Research Database (Denmark)

Montgomery, Melanie; Frandsen, Flemming; Larsen, OH

2001-01-01

As a part of ELSAMS development programme into alternative energy sources, various concepts of straw-firing have been investigated. This paper concerns co-firing of straw with coal to reduce the corrosion rate observed in straw-fired power plants. Co-firing with coal reduces the amount of potassium......: a) the exposure of metal rings on water/air cooled probes, and b) the exposure of a range of materials built into the existing superheaters. A range of austenitic and ferritic steels was exposed in the steam temperature region of 520-580°C. The flue gas temperature ranged from 925-1100°C....... The corrosion products for the various steel types were investigated using light optical and scanning electron microscopy. Corrosion mechanisms for the austenitic and ferritic steels are presented. These are discussed in relation to temperature and deposit composition. Co-firing with coal has removed potassium...

Effective technology of wood and gaseous fuel co-firing for clean energy production

International Nuclear Information System (INIS)

Zake, M.; Barmina, I.; Gedrovics, M.; Desnickis, A.

2007-01-01

The main aim of the study was to develop and optimise a small-scale experimental co-firing technique for the effective and clean heat energy production by replacing a proportion of fossil fuel (propane) with renewable one (wood biomass). Technical solutions of propane co-fire presenting two different ways of additional heat supply to the wood biomass are proposed and analysed. The experiments have shown that a better result can be obtained for the direct propane co-fire of the wood biomass, when the rate of wood gasification and the ignition of volatiles are controlled by additional heat energy supply to the upper portion of wood biomass. A less effective though cleaner way of heat energy production is the direct propane co-fire of volatiles when low-temperature self-sustaining burnout of the wood biomass controls the rate of the volatile formation, while additional heat energy supply to the flow of volatiles controls their burnout. The effect of propane co-fire on the heat production rate and the composition of polluting emissions is studied and analysed for different rates of the additional heat supply to the wood biomass and of the swirling air supply as well as for different charge of wood biomass above the inlet of the propane flame flow. (Authors)

Optimal Level of Woody Biomass Co-Firing with Coal Power Plant Considering Advanced Feedstock Logistics System

Directory of Open Access Journals (Sweden)

Sangpil Ko

2018-05-01

Full Text Available Co-firing from woody biomass feedstock is one of the alternatives toward increased use of renewable feedstock in existing coal power plants. However, the economic level of co-firing at a particular power plant depends on several site-specific factors. Torrefaction has been identified recently as a promising biomass pretreatment option to lead to reduction of the feedstock delivered cost, and thus facilitate an increase in the co-firing ratio. In this study, a mixed integer linear program (MILP is developed to integrate supply chain of co-firing and torrefaction process and find the optimal level of biomass co-firing in terms of minimized transportation and logistics costs, with or without tax credits. A case study of 26 existing coal power plants in three Great Lakes States of the US is used to test the model. The results reveal that torrefaction process can lead to higher levels of co-firing, but without the tax credit, the effect is limited to the low capacity of power plants. The sensitivity analysis shows that co-firing ratio has higher sensitivity to variation in capital and operation costs of torrefaction than to the variation in the transportation and feedstock purchase costs.

Mechanical properties of zirconia core-shell rods with porous core and dense shell prepared by thermoplastic co-extrusion

Czech Academy of Sciences Publication Activity Database

Kaštyl, J.; Chlup, Zdeněk; Clemen, F.; Trunec, M.

2017-01-01

Roč. 37, č. 6 (2017), s. 2439-2447 ISSN 0955-2219 R&D Projects: GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : ceramic injection moldings * oxide fuel -cells * electrophoretic deposition * large pores * alumina * fabrication * behavior * tubes * bioceramics * composites * Zirconia * Co-extrusion * Core-shell * Porous structure * Mechanical properties Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 3.411, year: 2016

Characterization of ceramics used in mass ceramic industry Goianinha/RN

International Nuclear Information System (INIS)

Sales Junior, J.C.C.; Nascimento, R.M. do; Andrade, J.C.S.; Saldanha, K.M.; Dutra, R.P.S.

2011-01-01

The preparation of the the ceramic mass is one of the most important steps in the manufacture of ceramic products, since the characteristics of the raw materials used, and the proportions that they are added, directly influence the final properties of ceramic products and the operational conditions of processing. The objective of this paper is to present the results of the characterization of a ceramic mass used in the manufacture of sealing blocks by a red ceramic industry of the city of Goianinha / RN. We analyzed the chemical and mineralogical composition; thermogravimetric and differential thermal analysis; granulometric analysis; evaluation of plasticity; and determining the technological properties of specimens used in test firing at 700, 900 and 1100 ° C. The results show that the ceramic body studied has characteristics that allow use in the manufacture of sealing blocks when burned at a temperature of 900 ° C. (author)

Novel low-temperature sintering ceramic substrate based on indialite/cordierite glass ceramics

Science.gov (United States)

Varghese, Jobin; Vahera, Timo; Ohsato, Hitoshi; Iwata, Makoto; Jantunen, Heli

2017-10-01

In this paper, a novel low-temperature sintering substrate for low temperature co-fired ceramic applications based on indialite/cordierite glass ceramics with Bi2O3 as a sintering aid showing low permittivity (εr) and ultralow dielectric loss (tan δ) is described. The fine powder of indialite was prepared by the crystallization of cordierite glass at 1000 °C/1 h. The optimized sintering temperature was 900 °C with 10 wt % Bi2O3 addition. The relative density achieved was 97%, and εr and tan δ were 6.10 and 0.0001 at 1 MHz, respectively. The composition also showed a moderately low temperature coefficient of relative permittivity of 118 ppm/°C at 1 MHz. The obtained linear coefficient of thermal expansion was 3.5 ppm/°C in the measured temperature range of 100 to 600 °C. The decreasing trend in dielectric loss, the low relative permittivity at 1 MHz, and the low thermal expansion of the newly developed composition make it an ideal choice for radio frequency applications.

Experimental analysis of a combustion reactor under co-firing coal with biomass

Energy Technology Data Exchange (ETDEWEB)

Pereira, Fabyo Luiz; Bazzo, Edson; Oliveira Junior, Amir Antonio Martins de [Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil). LabCET], e-mail: ebazzo@emc.ufsc.br; Bzuneck, Marcelo [Tractebel Energia S.A., Complexo Termeletrico Jorge Lacerda, Capivari de Baixo, SC (Brazil)], e-mail: marcelob@tractebelenergia.com.br

2010-07-01

Mitigation of greenhouse gases emission is one of the most important issues in energy engineering. Biomass is a potential renewable source but with limited use in large scale energy production because of the relative smaller availability as compared to fossil fuels, mainly to coal. Besides, the costs concerning transportation must be well analysed to determine its economic viability. An alternative for the use of biomass as a primary source of energy is the co-firing, that is the possibility of using two or more types of fuels combined in the combustion process. Biomass can be co-fired with coal in a fraction between 10 to 25% in mass basis (or 4 to 10% in heat-input basis) without seriously impacting the heat release characteristics of most boilers. Another advantage of cofiring, besides the significant reductions in fossil CO{sub 2} emissions, is the reduced emissions of NO{sub x} and SO{sub x}. As a result, co-firing is becoming attractive for power companies worldwide. This paper presents results of some experimental analysis on co-firing coal with rice straw in a combustion reactor. The influence of biomass thermal share in ash composition is also discussed, showing that alkali and earth alkaline compounds play the most important role on the fouling and slagging behavior when co-firing. Some fusibility correlations that can assist in the elucidation of these behavior are presented and discussed, and then applied to the present study. Results show that for a biomass thermal share up to 20%, significant changes are not expected in fouling and slagging behavior of ash. (author)

Fire modifies the phylogenetic structure of soil bacterial co-occurrence networks.

Science.gov (United States)

Pérez-Valera, Eduardo; Goberna, Marta; Faust, Karoline; Raes, Jeroen; García, Carlos; Verdú, Miguel

2017-01-01

Fire alters ecosystems by changing the composition and community structure of soil microbes. The phylogenetic structure of a community provides clues about its main assembling mechanisms. While environmental filtering tends to reduce the community phylogenetic diversity by selecting for functionally (and hence phylogenetically) similar species, processes like competitive exclusion by limiting similarity tend to increase it by preventing the coexistence of functionally (and phylogenetically) similar species. We used co-occurrence networks to detect co-presence (bacteria that co-occur) or exclusion (bacteria that do not co-occur) links indicative of the ecological interactions structuring the community. We propose that inspecting the phylogenetic structure of co-presence or exclusion links allows to detect the main processes simultaneously assembling the community. We monitored a soil bacterial community after an experimental fire and found that fire altered its composition, richness and phylogenetic diversity. Both co-presence and exclusion links were more phylogenetically related than expected by chance. We interpret such a phylogenetic clustering in co-presence links as a result of environmental filtering, while that in exclusion links reflects competitive exclusion by limiting similarity. This suggests that environmental filtering and limiting similarity operate simultaneously to assemble soil bacterial communities, widening the traditional view that only environmental filtering structures bacterial communities. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

What every surgeon should know about Ceramic-on-Ceramic bearings in young patients

OpenAIRE

Hernigou, Philippe; Roubineau, Fran?ois; Bouthors, Charlie; Flouzat-Lachaniette, Charles-Henri

2016-01-01

Based on the exceptional tribological behaviour and on the relatively low biological activity of ceramic particles, Ceramic-on-Ceramic (CoC) total hip arthroplasty (THA) presents significant advantages CoC bearings decrease wear and osteolysis, the cumulative long-term risk of dislocation, muscle atrophy, and head-neck taper corrosion. However, there are still concerns regarding the best technique for implantation of ceramic hips to avoid fracture, squeaking, and revision of ceramic hips with...

Effect of metal selection and porcelain firing on the marginal accuracy of titanium-based metal ceramic restorations.

Science.gov (United States)

Shokry, Tamer E; Attia, Mazen; Mosleh, Ihab; Elhosary, Mohamed; Hamza, Tamer; Shen, Chiayi

2010-01-01

Titanium is the most biocompatible metal used for dental casting; however, there is concern about its marginal accuracy after porcelain application since this aspect has direct influence on marginal fit. The purpose of this study was to determine the effect that metal selection and the porcelain firing procedure have on the marginal accuracy of metal ceramic prostheses. Cast CP Ti, milled CP Ti, cast Ti-6Al-7Nb, and cast Ni-Cr copings (n=5) were fired with compatible porcelains (Triceram for titanium-based metals and VITA VMK 95 for Ni-Cr alloy). The Ni-Cr alloy fired with its porcelain served as the control. Photographs of metal copings placed on a master die were made. Marginal discrepancy was determined on the photographs using an image processing program at 8 predetermined locations before airborne-particle abrasion for porcelain application, after firing of the opaque layer, and after firing of the dentin layer. Repeated-measures 2-way ANOVA was used to investigate the effect of metal selection and firing stage, and paired t tests were used to determine the effect of each firing stage within each material group (alpha=.05). ANOVA showed that both metal selection and firing stage significantly influenced the measured marginal discrepancy (Pcast Ti-6Al-7Nb alloy (P=.003). Titanium copings fabricated by CAD/CAM demonstrated the least marginal discrepancy among all groups, while the base metal (Ni-Cr) groups exhibited the most discrepancy of all groups tested. Copyright 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Spectroscopic properties of Er3+ and Yb3+ co-doped glass ceramics containing SrF2 nanocrystals

International Nuclear Information System (INIS)

Qiao Xvsheng; Fan Xianping; Wang Minquan; Zhang Xianghua

2009-01-01

The spectroscopic properties of Er 3+ /Yb 3+ co-doped 50SiO 2 -10Al 2 O 3 -20ZnF 2 -20SrF 2 glass and glass ceramic containing SrF 2 nanocrystals were investigated. The formation of SrF 2 nanocrystals in the glass ceramic was confirmed by XRD. The oscillator strengths for several transitions of the Er 3+ ions in the glass ceramic have been obtained and the Judd-Ofelt parameters were then determined. The XRD result and Judd-Ofelt parameters suggested that Er 3+ and Yb 3+ ions had efficiently enriched in the SrF 2 nanocrystals in the glass ceramic. The lifetime of excited states has been used to reveal the surroundings of luminescent Er 3+ and Yb 3+ and energy transfer (ET) mechanism between Er 3+ and Yb 3+ . Much stronger upconversion luminescence and longer lifetime of the Er 3+ /Yb 3+ co-doped glass ceramic were observed in comparison with the Er 3+ /Yb 3+ co-doped glass, which could be ascribed to more efficient ET from Yb 3+ to Er 3+ due to the enrichment of Yb 3+ and Er 3+ and the shortening of the distance between lanthanide ions in the precipitated SrF 2 nanocrystals.

CFD simulation of coal and straw co-firing

DEFF Research Database (Denmark)

Junker, Helle; Hvid, Søren L.; Larsen, Ejvind

This paper presents the results of a major R&D program with the objective to develop CFD based tools to assess the impact of biomass co-firing in suspension fired pulverized coal power plants. The models have been developed through a series of Danish research projects with the overall objective...... to collect results from fundamental research and make it operational in boiler design through implementation in a Computational Fluid Dynamics based simulation tool. This paper summarizes the developments in modeling of; particle motion, particle conversion, ash deposition on heat transfer surfaces, and NOx...

Fabrication and spectroscopic properties of Co:MgAl2O4 transparent ceramics by the HIP post-treatment

Science.gov (United States)

Luo, Wei; Ma, Peng; Xie, Tengfei; Dai, Jiawei; Pan, Yubai; Kou, Huamin; Li, Jiang

2017-07-01

Cobalt-doped magnesium aluminate spinel (Co:MgAl2O4) is one of the most important saturable absorbers for the passive Q-switching of solid-state lasers operating at eye-safe wavelength of 1.5 μm. In this work, highly transparent Co:MgAl2O4 ceramics were fabricated by vacuum sintering combined with hot isostatic pressing (HIP) post-treatment, using the mixture of the commercial spinel and the lab-made Co:MgAl2O4 powder as the raw materials. The densification mechanism of Co:MgAl2O4 transparent ceramics was discussed. The microstructure and optical properties of the samples were investigated. The ground state absorption cross section (σGSA) was calculated from the fitted curve of the absorption coefficient spectrum. The results show that Co:MgAl2O4 ceramics fabricated by vacuum sintering at 1500 °C for 5 h and then HIP post-treatment at 1650 °C for 3 h perform good transparency, whose in-line transmittance exceeds 80% at 2500 nm. Moreover, the ground state absorption cross section of 0.02 at.% Co:MgAl2O4 ceramics is calculated to be 3.35 × 10-19 cm2 at the wavelength of 1540 nm, which is promising for the application to the passive Q-switching of solid-state laser operating in the near infrared region (NIR).

Mechanical Integrity Issues at MCM-Cs for High Reliability Applications

International Nuclear Information System (INIS)

Morgenstern, H.A.; Tarbutton, T.J.; Becka, G.A.; Uribe, F.; Monroe, S.; Burchett, S.

1998-01-01

During the qualification of a new high reliability low-temperature cofired ceramic (LTCC) multichip module (MCM), two issues relating to the electrical and mechanical integrity of the LTCC network were encountered while performing qualification testing. One was electrical opens after aging tests that were caused by cracks in the solder joints. The other was fracturing of the LTCC networks during mechanical testing. Through failure analysis, computer modeling, bend testing, and test samples, changes were identified. Upon implementation of all these changes, the modules passed testing, and the MCM was placed into production

What every surgeon should know about Ceramic-on-Ceramic bearings in young patients.

Science.gov (United States)

Hernigou, Philippe; Roubineau, François; Bouthors, Charlie; Flouzat-Lachaniette, Charles-Henri

2016-04-01

Based on the exceptional tribological behaviour and on the relatively low biological activity of ceramic particles, Ceramic-on-Ceramic (CoC) total hip arthroplasty (THA) presents significant advantagesCoC bearings decrease wear and osteolysis, the cumulative long-term risk of dislocation, muscle atrophy, and head-neck taper corrosion.However, there are still concerns regarding the best technique for implantation of ceramic hips to avoid fracture, squeaking, and revision of ceramic hips with fracture of a component.We recommend that surgeons weigh the potential advantages and disadvantages of current CoC THA in comparison with other bearing surfaces when considering young very active patients who are candidates for THA. Cite this article: Hernigou P, Roubineau F, Bouthors C, Flouzat-Lachaniette C-H. What every surgeon should know about Ceramic-on-Ceramic bearings in young patients. EFORT Open Rev 2016;1:107-111. DOI: 10.1302/2058-5241.1.000027.

Seasonal Variations of Atmospheric CO2 over Fire Affected Regions Based on GOSAT Observations

Science.gov (United States)

Shi, Y.; Matsunaga, T.

2016-12-01

Abstract: The carbon dioxide (CO2) emissions released from biomass burning significantly affect the temporal variations of atmospheric CO2 concentrations. Based on a long-term (July 2009-June 2015) retrieved datasets by the Greenhouse Gases Observing Satellite (GOSAT), the seasonal cycle and interannual variations of column-averaged volume mixing ratios of atmospheric carbon dioxide (XCO2) in four fire affected continental regions were investigated. The results showed Northern Africa had the largest seasonal variations after removing its regional long-term trend of XCO2 with peak-to-peak amplitude of 6.2 ppm within the year, higher than central South America (2.4 ppm), Southern Africa (3.8 ppm) and Australia (1.7 ppm). The detrended regional XCO2 was found to be positively correlated with the fire CO2 emissions during fire activity period and negatively correlated with vegetation photosynthesis activity with different seasonal variabilities. Northern Africa recorded the largest change of seasonal variations of detrended XCO2 with a total of 12.8 ppm during fire seasons, higher than central South America, Southern Africa and Australia with 5.4 ppm, 6.7 ppm and 2.2 ppm, respectively. During fire episode, the positive detrended XCO2 was noticed during June-November in central South America, December-June in Northern Africa, May-November in Southern Africa. The Pearson correlation coefficients between the variations of detrended XCO2 and fire CO2 emissions from GFED4 (Global Fire Emissions Database v4) achieved best correlations in Southern Africa (R=0.77, p<0.05). Meanwhile, Southern Africa also experienced a significant negative relationship between the variations of detrended XCO2 and vegetation activity (R=-0.84, p<0.05). This study revealed that fire CO2 emissions and vegetation activity contributed greatly to the seasonal variations of GOSAT XCO2 dataset.

Co-firing of coal with biomass and waste in full-scale suspension-fired boilers

Energy Technology Data Exchange (ETDEWEB)

Dam-Johansen, Kim; Frandsen, Flemming J.; Jensen, Peter A.; Jensen, Anker D. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of chemical and Biochemical Engineering

2013-07-01

The energy policy in Denmark has for many years focused on lowering the net CO{sub 2} emission from heat and power production by replacing fossil fuels by renewable resources. This has been done by developing dedicated grate-fired boilers for biomass and waste fuels but also by developing coal-based suspension-fired boilers to accept still higher fractions of biomass or waste material as fuels. This last development has been challenging of many reasons, including pre-treatment of fuels, and solving potential emission and operational problems during the simultaneous development of supercritical steam cycles with steam temperatures close to 600 C, providing power efficiencies close to 50% (Hein KRG, Sustainable energy supply and environment protection - strategies, resources and technologies. In: Gupta R, Wall T, Hupa M, Wigley F, Tillman D, Frandsen FJ (eds) Proceedings of international conference on impact of fuel quality on power production and the environment, Banff Conference Centre, Banff, Alberta, Canada, 29 Sept-4 Oct, 2008). For 25 years the CHEC (Combustion and Harmful Emission Control) Research Centre at DTU Chemical Engineering, has attained a leading role in research, supporting power producing industry, plant owners and boiler manufacturers to optimize design and operation and minimize cost and environmental impact using alternative fuels in suspension fired boilers. Our contribution has been made via a combination of full-scale measuring campaigns, pilot-scale studies, lab-scale measurements and modeling tools. The research conducted has addressed many issues important for co-firing, i.e. fuel processing, ash induced boiler deposit formation and corrosion, boiler chamber fuel conversion and emission formation, influence on flue gas cleaning equipment and the utilization of residual products. This chapter provides an overview of research activities, aiming at increasing biomass shares during co-firing in suspension, conducted in close collaboration with

BENEFIT COST FOR BIOMASS CO-FIRING IN ELECTRICITY GENERATION: CASE OF UTAH, U.S.

Directory of Open Access Journals (Sweden)

Man-Keun Kim

2015-07-01

Full Text Available Policy making regarding biomass co-firing is difficult. The article provides a benefit-cost analysis for decision makers to facilitate policy making process to implement efficient biomass co-firing policy. The additional cost is the sum of cost of the biomass procurement and biomass transportation. Co-benefits are sales of greenhouse gas emission credits and health benefit from reducing harmful air pollutants, especially particulate matter. The benefit-cost analysis is constructed for semi-arid U.S. region, Utah, where biomass supply is limited. Results show that biomass co-firing is not economically feasible in Utah but would be feasible when co-benefits are considered. Benefit-cost ratio is critically dependent upon biomass and carbon credit prices. The procedure to build the benefit-cost ratio can be applied for any region with other scenarios suggested in this study.

TECHNOLOGY OF PRODUCTION OF CERAMIC TILES BASED ON DOLERITE AND FUSIBLE CLAY

Directory of Open Access Journals (Sweden)

Pleshko Marianna Viktorovna

2018-02-01

Full Text Available The paper presents a completely new composition of the ceramic mass for production of ceramic tiles for interior lining of walls, on the basis of fusible clay. The optimal compositions of jade engobe and glossy glaze, the most suitable for this composition, are determined. A new technological scheme is developed for production of ceramic tiles for interior lining based on dolerite and fusible clay. The curve of firing, which is the most suitable for charge masses and decorative coating compositions being used, has been constructed. Subject: ceramic mass for the production of ceramic facing tiles. Ceramic tiles are the most popular building material in Russia. The most promising technology for its production from the standpoint of technical and economic efficiency is the technology of rapid single firing, which is rarely used at the plants of our country. In this regard, the development and implementation of new effective compositions of ceramic masses and decorative coatings that are the most compatible with the specifics of rapid single firing technology, based on new unconventional raw materials, are very relevant and promising. Research objectives: development of technological parameters, compositions of ceramic masses and decorative coatings of ceramic tiles for the internal wall lining that provide an increase in tiles production efficiency using the technology of rapid single firing through the use of non-traditional plagioclase-pyroxene raw materials: dolerites, loam and technogenic raw materials. Materials and methods: technological, numerical and experimental studies were conducted. To select the optimal composition of the ceramic mass, the method of mathematical planning was used, namely the simplex-centroid design of Scheffe. To identify the scientific foundations of the energy-efficient production technology being developed, differential thermal and X-ray phase, optical, electron microscopic and dilatometric studies were applied

Easy Debonding of Ceramic Brackets Bonded with a Light-Cured Orthodontic Adhesive Containing Microcapsules with a CO2 Laser.

Science.gov (United States)

Arima, Shiori; Namura, Yasuhiro; Tamura, Takahiko; Shimizu, Noriyoshi

2018-03-01

An easy debonding method for ceramic brackets using a light-cured Bis-GMA resin containing heat-expandable microcapsules and CO 2 laser was investigated. Ceramic brackets are used frequently in orthodontic treatment because of their desirable esthetic properties. However, the application of heavy force to ceramic brackets in debonding can fracture the tooth enamel and ceramic brackets, causing tooth pain. In total, 60 freshly extracted bovine permanent mandibular incisors were divided randomly into 10 groups of 6 specimens each, corresponding to the number of variables tested. Ceramic brackets were bonded to bovine permanent mandibular incisors using an orthodontic bonding agent containing heat-expandable microcapsules at different levels (0-30 wt%) and resin composite paste, and cured by a curing device. The bond strengths were measured before and after CO 2 laser irradiation, and the temperature increase in the pulp chamber in fresh human first premolars was also evaluated. With CO 2 laser irradiation for 5 sec to the bracket, the bond strength in the 25% microcapsule group decreased significantly, to ∼0.17-fold, compared with that of the no-laser group (p brackets, with less debonding time and enamel damage.

Characterization of the interaction between glazes and ceramic bodies

Czech Academy of Sciences Publication Activity Database

Kavanová, M.; Kloužková, A.; Kloužek, Jaroslav

2017-01-01

Roč. 61, č. 3 (2017), s. 267-275 ISSN 0862-5468 Institutional support: RVO:67985891 Keywords : glazes * ceramic s * thermal analysis * coefficients of the thermal expansion * dilatometry Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass OBOR OECD: Ceramic s Impact factor: 0.439, year: 2016

Nano-oxides to improve the surface properties of ceramic tiles

International Nuclear Information System (INIS)

Rambaldi, E.; Tucci, A.; Esposito, L.; Naldi, D.; Timellini, G.

2010-01-01

The aim of the present work is to realise ceramic tiles with superior surface mechanical characteristics and chemical resistance, by the addition of nano-oxides, such as zirconia and alumina, since such advanced ceramics oxides are well known for their excellent mechanical properties and good resistance to chemical etching. In order to avoid any dangerousness, the nanoparticles were used in form of aqueous suspension and they were sprayed, by airbrush, directly onto the dried ceramic support, before firing. To observe the distribution of the nanoparticles and to optimise the surface treatment, SEM-EDS analyses were carried out on the fired samples. XRD analysis was conducted to assess the phases evolution of the different materials during the firing step. The surface mechanical characteristics of the samples have been evaluated by Vickers hardness and scratch test. In addition, also chemical resistance tests were performed. Microstructural observations allowed to understand how alumina and zirconia nanoparticles acted to improve the surface performances of the modified ceramic tiles. (Author) 20 refs.

CO2 and Nd:YAP laser interaction with lithium disilicate and Zirconia dental ceramics: A preliminary study

Science.gov (United States)

Rocca, Jean-Paul; Fornaini, Carlo; Brulat-Bouchard, Nathalie; Bassel Seif, Samy; Darque-Ceretti, Evelyne

2014-04-01

Lithium disilicate and Zirconia ceramics offer a high level of accuracy when used in prosthetic dentistry. Their bonding using different resins is highly dependent on micro-mechanical interlocking and adhesive chemical bonding. Investigation of the performances of high strength ceramics when their surface is modified for chemical and mechanical bonding is then required. The aim of this study is to investigate the possibility of using laser for surface treatment of different high strength CAD/CAM ceramics and thus to improve their mechanical and chemical properties. Thirty two CAD/CAM ceramic discs were divided into two different groups: lithium disilicate ceramics (IPS e.max CAD®, Ivoclar, Vivadent, Italy) and Zirconia ceramics (IPS e.max ZirCAD®, Ivoclar, Vivadent, Italy). The Laser surface treatment was performed by Carbon Dioxide laser (Dream Pulse Laser®, Daeshin Enterprise Corp., Korea) at 20 W, 25 W and 30 W CW and by Neodymium Yttrium Aluminum Perovskite laser (Nd:YAP Lokki®, Lobel Medical, France) at 10 W and 30 Hz. Physical modifications of the irradiated ceramic discs were observed by scanning electron microscopy (SEM) and chemically analyzed by Energy-Dispersive Spectroscopy (EDS). Surface wettability was tested using the water drop test and the crystalline structure was investigated using X-ray diffraction (XRD). The macroscopic observation showed a shinier structure in all the groups, while at the SEM observation only CO2 25 W and 30 W treated groups showed cracks and fissures. In the conditions of this study, CO2 laser and Nd:YAP laser with the parameters used create chemical and physical surface modifications of the ceramics, indicating the possibility of an improvement in adhesion of the tested ceramics.

Estimation of CO{sub 2}-emissions from Fires in Dwellings, Schools and Cars in the Nordic Countries

Energy Technology Data Exchange (ETDEWEB)

Blomqvist, Per; Simonson McNamee, Margaret

2009-07-01

Updated estimates of emissions from fires in dwellings, schools, pre schools and cars are presented for the Nordic countries with the exception of Iceland. The updated emissions are calculated based on fire statistics from 2007 and are compared to results previously presented for 1994 in Sweden. To put the fire emissions data into perspective they are also compared to national estimates of CO{sub 2} emissions as reported by the Swedish EPA to the EU in their National Inventory Report for 2007. The statistical data on fires for Sweden for 2007 is more reliable compared with the data for 1994, which strengthens the updated emission estimate. The major uncertainty in the fire data used for the emission estimate is the interpretation of fire spread which is based on rather crude assumptions. In particular in the case of houses the fire spread area used for the estimate may be an exaggeration thereby giving a possible overestimation of the estimated emissions. Data indicates that the total emission of CO{sub 2} from fires in dwellings (including single family homes, semi-detached houses, summer houses and apartments) in Sweden 2007 is 15,5 kton. Similar values for Denmark (4,1 kton), Finland (6,9 kton) and Norway (6,4 kton). Similar data for school/preschool and car fires indicate that emissions in Sweden are higher than in the other Nordic countries for these categories as well although not by as great an amount. Finally, a comparison between emissions data from other sources of CO{sub 2} and those from fires indicate that emissions of CO{sub 2} from fires are minor compared to most other sources. The previous study based on statistics from 1994 also concluded that fires are a minor source of CO{sub 2} but a relatively significant source of, e.g., particulate matter, VOC, PAH and other large organic species

A Quantum Cascade Laser-Based CO Sensor for Fire Warning, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Maxion Technologies, Inc. (Maxion) proposes to develop and field test a Carbon Monoxide (CO)-sensor prototype for post fire cleanup and CO detection. The sensor will...

Fighting fire with gas. CO{sub 2} extinguishes smouldering fires in biomass silos and waste bunkers; Effizientes Feuerwehr-Gas. CO{sub 2} loescht Schwelbraende in Biomasse-Silos und Abfallbunkern

Energy Technology Data Exchange (ETDEWEB)

Anon.

2011-07-01

Organic materials are a great source of energy and so biomass is in big demand. But wherever large amounts of wood, waste and straw are stored in huge silos, there is also a risk of smouldering fires and even explosions. Conventional methods are relatively ineffective at extinguishing fires such as these. But a new extinguishing system from Linde uses CO{sub 2} to effectively fight smouldering fires at the source. (orig.)

Effects of using kaolin waste and granite waste as raw materials for the production of low-water absorption ceramic tiles; Efeitos da co-utilizacao dos residuos do beneficiamento do caulim e da extracao do granito rain forest para a producao de revestimentos ceramicos com baixa absorcao de agua

Energy Technology Data Exchange (ETDEWEB)

Freires, H.P.; Argonz, R.; Nogueira, R.E.F.Q.; Sasaki, J.M., E-mail: argonz@ufc.br [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil); Sales, J.C. [Universidade do Vale do Aracau (UVA), Crateus, CE (Brazil)

2012-07-01

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)

Tensile Properties of Open Cell Ceramic Foams

Czech Academy of Sciences Publication Activity Database

Dlouhý, Ivo; Řehořek, Lukáš; Chlup, Zdeněk

2009-01-01

Roč. 409, - (2009), s. 168-175 ISSN 1013-9826. [Fractography of Advanced Ceramics /3./. Stará Lesná, 07.09.2008-10.09.2008] R&D Projects: GA ČR(CZ) GA106/06/0724; GA ČR GD106/05/H008 Institutional research plan: CEZ:AV0Z20410507 Keywords : tensile test * ceramics foam * open porosity * tensile strength Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

Method for preparing corrosion-resistant ceramic shapes

Science.gov (United States)

Arons, R.M.; Dusek, J.T.

1979-12-07

Ceramic shapes having impermeable tungsten coatings can be used for containing highly corrosive molten alloys and salts. The shapes are prepared by coating damp green ceramic shapes containing a small amount of yttria with a tungsten coating slip which has been adjusted to match the shrinkage rate of the green ceramic and which will fire to a theoretical density of at least 80% to provide an impermeable coating.

MHD oxidant intermediate temperature ceramic heater study

Science.gov (United States)

Carlson, A. W.; Chait, I. L.; Saari, D. P.; Marksberry, C. L.

1981-09-01

The use of three types of directly fired ceramic heaters for preheating oxygen enriched air to an intermediate temperature of 1144K was investigated. The three types of ceramic heaters are: (1) a fixed bed, periodic flow ceramic brick regenerative heater; (2) a ceramic pebble regenerative heater. The heater design, performance and operating characteristics under conditions in which the particulate matter is not solidified are evaluated. A comparison and overall evaluation of the three types of ceramic heaters and temperature range determination at which the particulate matter in the MHD exhaust gas is estimated to be a dry powder are presented.

CO2 separation from biogas with ceramic membranes

International Nuclear Information System (INIS)

Fassauer, Burkhardt; Richter, Hannes; Schwarz, Bjoern; Reger-Wagner, Norman; Kaemnitz, Susanne; Lubenau, Udo; Mothes, Raimund

2015-01-01

Biogas contains after the production of up to 55% CO 2 . In order to use biogas as a fuel or to feed it into the natural gas network, it must be purified before. Adsorption and scrubbing processes are primarily used technically. Membrane processes offer the advantage of continuous operation and a simple modular and flexible system design, which imply relatively low investment costs and low energy needs. Moreover, membrane systems can be started up and shut down quickly without any problems. Ceramic membranes are characterised by high stability (thermal, chemical, mechanical) and very high flows in comparison to polymeric membranes. [de

Norwegian wood? Biomass co-firing at Drax

Energy Technology Data Exchange (ETDEWEB)

Probert, T.

2009-11-15

PEi reports on a visit to the giant Drax coal fired power station in North Yorkshire, UK. The second largest coal plant in Europe is the site of a co-firing system that will allow for the displacement of ten per cent of its coal throughput in favour of biomass, thus reducing its sizeable carbon footprint by around two million tonnes a year. Tests on a pilot plant have shown that Drax can burn up to 60 types of biomass using existing coal burners. The majority of biomass will be imported - most likely wood from Scandinavia, The Baltics and North America. Drax would be eligible for one-half of a Renewable Obligation Certificate. Carbon dioxide emissions should be reduced by around 2 million tonnes per year. 3 photos.

Method of using sacrificial materials for fabricating internal cavities in laminated dielectric structures

Science.gov (United States)

Peterson, Kenneth A [Albuquerque, NM

2009-02-24

A method of using sacrificial materials for fabricating internal cavities and channels in laminated dielectric structures, which can be used as dielectric substrates and package mounts for microelectronic and microfluidic devices. A sacrificial mandrel is placed in-between two or more sheets of a deformable dielectric material (e.g., unfired LTCC glass/ceramic dielectric), wherein the sacrificial mandrel is not inserted into a cutout made in any of the sheets. The stack of sheets is laminated together, which deforms the sheet or sheets around the sacrificial mandrel. After lamination, the mandrel is removed, (e.g., during LTCC burnout), thereby creating a hollow internal cavity in the monolithic ceramic structure.

Minimising the Spurious TL of Recently Fired Ceramics Using the Foil Technique

International Nuclear Information System (INIS)

Michael, C.T.; Zacharias, N.; Polikreti, K.; Pagonis, V.

1999-01-01

The new foil technique for measuring the natural dose in TL dating is briefly presented. In this technique very thin samples are made with the necessary plasticity to achieve the best heating contact between sample and heater plate. Measurements can then be made in vacuum and it is possible to use higher heating rates. The effect of the increase of the TL signal with the increase of the heating rate is presented. The foil technique reduces chemiluminescence and increases the TL signal. This allows the application of TL dating to be extended to lower limits (lower ages). These limits are determined by estimating quantitatively the effects of the sample preparation procedure on the induction of spurious TL (triboluminescence). Samples from a two year old ceramic vase were prepared with two different powder preparation procedures: (a) by using a hand drill with a common steel edge and (b) by crushing a piece using a vice. Measurements at a heating rate of 50 deg. C.s -1 were made. The two estimates of P (total dose) provide an estimate of age for each procedure. The age estimation for the vice prepared sample is about 30 years and for the drilled sample is higher than 120 years. It is suggested that the use of a drill for powder preparation be avoided, especially in TL dating and authenticity tests of recently fired ceramics (less than 500 years). (author)

Firing temperature of pottery using TL and OSL techniques

International Nuclear Information System (INIS)

Polymeris, G.S.; Sakalis, A.; Papadopoulou, D.; Dallas, G.; Kitis, G.; Tsirliganis, N.C.

2007-01-01

Several methods of thermal analysis are used to determine in the laboratory the firing temperature of ancient ceramic sherds. These methods are based primarily on changes of physical characteristics occurring when clay minerals are heated. The luminescence properties of quartz grains in a ceramic matrix also undergo certain changes during firing. The possibility of measuring the sensitivity change (sensitization) of quartz in order to determine the firing temperature of archeological ceramic artifacts was investigated. The sensitivity change was studied for both the thermoluminescence (TL) and the optically stimulated luminescence (OSL) signal for a ceramic sample of known firing temperature. Various segments of the sample were annealed to a different temperature. Subsequently, the initial sensitivity, as well as the thermal and the pre-dose sensitization were measured for both TL and OSL at room temperature as a function of the annealing temperature. The obtained TL glow curves showed different shapes for annealing temperatures above the firing temperature. Thermal and pre-dose sensitizations also exhibited a similar, although less prominent, rise. The OSL signal was analyzed by integrating the raw signal over the initial second of stimulation. The initial sensitivity showed an abrupt change for annealing temperatures around the firing temperature. An alternative approach used for the analysis of the OSL signal involved a full-component resolved sensitization study. The same abrupt change for the initial sensitivity of both the first and second components was observed, as well as, a clear but not very prominent thermal sensitization trend for annealing temperatures above the firing temperature

Analysis and study on the membrane method of CO2 removal of coal-fired boilers

International Nuclear Information System (INIS)

Fangqin, Li; Henan, Li; Jianxing, Ren; Jiang, Wu; Zhongzhu, Qiu

2010-01-01

Carbon dioxide (CO 2 ) is one kind of harmful substances from the burning process of fossil fuel. CO 2 emissions cause serious pollution on atmospheric environment, especially greenhouse effect. In this paper, CO 2 formation mechanism and control methods were researched. Membrane technology was studied to control CO 2 emissions from coal-fired boilers. The relationship between CO 2 removal efficiency and parameters of membrane contactor was analyzed. Through analysis and study, factors affecting on CO 2 removal efficiency were gotten. How to choose the best parameters was known. This would provide theoretical basis for coal-fired utility boilers choosing effective way of CO 2 removal. (author)

Sulphur capture by co-firing sulphur containing fuels with biomass fuels - optimization

International Nuclear Information System (INIS)

Nordin, A.

1992-12-01

Previous results concerning co-firing of high sulphur fuels with biomass fuels have shown that a significant part of the sulphur can be absorbed in the ash by formation of harmless sulphates. The aim of this work has been to (i) determine the maximum reduction that can be obtained in a bench scaled fluidized bed (5 kW); (ii) determine which operating conditions will give maximum reduction; (iii) point out the importance and applicability of experimental designs and multivariate methods when optimizing combustion processes; (iv) determine if the degree of sulphur capture can be correlated to the degree of slagging, fouling or bed sintering; and (v) determine if further studies are desired. The following are some of the more important results obtained: - By co-firing peat with biomass, a total sulphur retention of 70 % can be obtained. By co-firing coal with energy-grass, the total SO 2 emissions can be reduced by 90 %. - Fuel feeding rate, amount of combustion air and the primary air ratio were the most important operating parameters for the reduction. Bed temperature and oxygen level seem to be the crucial physical parameters. - The NO emissions also decreased by the sulphur reducing measures. The CO emissions were relatively high (130 mg/MJ) compared to large scale facilities due to the small reactor and the small fluctuations in the fuel feeding rate. The SO 2 emissions could however be reduced without any increase in CO emissions. - When the reactor was fired with a grass, the bed sintered at a low temperature ( 2 SO 4 and KCl are formed no sintering problems were observed. (27 refs., 41 figs., 9 tabs., 3 appendices)

Incorporation of flat glass in red ceramic

International Nuclear Information System (INIS)

Caldas, T.C.C.; Morais, A.S.C.; Pereira, P.S.; Monteiro, S.N.; Vieira, C.M.F.

2011-01-01

This work have as objective evaluate the effect of incorporation of up to 10% by weight of powdered flat glass , from civil industry, in red ceramic. The bodies were obtained by uniaxial pressing at 20 MPa and fired at temperatures of 850 ° C and 1050 ° C. The parameters studied were linear firing shrinkage, apparent density, water absorption and flexural rupture stress for the evaluation of the mechanical physical properties. The microstructure was observed by scanning electron microscopy and phase identification was performed by X-ray diffraction. The results showed that the waste changes the microstructure and properties of red ceramics. (author)

Investigation of medieval ceramics from Ras by physicochemical methods

Directory of Open Access Journals (Sweden)

Zindović Nataša D.

2008-01-01

Full Text Available Although early medieval Serbian ceramic is well described by the archeologists and historians, knowledge of the Balkan ceramic production is still limited. Archaeometric study of ceramics provenance, technology of preparation and used pigments as well as influence of neighboring countries and specific characteristics of different workshops has never been performed so far. The detailed knowledge of the micro-chemical and micro-structural nature of an archaeological artifact is critical in finding solutions to problems of restoration, conservation, dating and authentication in the art world. In this work we present results of systematic investigation of pottery shards from archeological site Ras. The term Ras, which signifies both the fortress and the region encompassing the upper course of Raška River, used to be the center of the medieval Serbian state. Both the ceramic body and the polychromatic glaze of the artifacts were studied by a multianalitical approach combining optical microscopy (OM, FT-IR spectroscopy and X-ray fluorescence (XRF. Mineralogical composition of pottery shards has been determined combining results obtained by FT-IR spectroscopy, after deconvolution of the spectra, and XRPD analysis. Firing temperature has been estimated based on the mineralogical composition and positions of Si-O stretching (-1000 cm-1 and banding (-460 cm-1 vibrations. Investigated samples have been classified into two groups based on the mineralogical composition, cross sections and firing temperature. Larger group consists of samples of fine-grained, homogeneous ceramics with firing temperatures bellow 800 °C which indicates imported products. Second, smaller group consists of inhomogeneous ceramics with firing temperatures between 850 and 900 °C produced in the domestic workshops. The obtained results will be used to build up a national database for the compositions of bodies, glazes and pigments.

Spectroscopic properties of Er/Nd co-doped yttrium lanthanum oxide transparent ceramics pumped at 980 nm

Energy Technology Data Exchange (ETDEWEB)

Shao, Yingjie; Yang, Qiuhong, E-mail: yangqiuhong@shu.edu.cn; Gui, Yan; Yuan, Ye; Lu, Qing

2016-05-15

(Er{sub 0.01}Nd{sub x}Y{sub 0.89-x}La{sub 0.1}){sub 2}O{sub 3} (x = 0, 0.001, 0.002, 0.005, 0.01) transparent ceramics were prepared by conventional ceramic processing. The Nd{sup 3+} content dependencies of mid-infrared, near infrared and up-conversion emission of Er{sup 3+} pumped at 980 nm were fully presented. Mechanism of energy transfer between Er{sup 3+} and Nd{sup 3+} was also demonstrated. The results showed that co-doping 0.1 at% Nd{sup 3+} into 1 at% Er{sup 3+} doped yttrium lanthanum oxide transparent ceramic enhanced the 2.7 μm emission significantly and meanwhile suppressed the 1.5 μm emission effectively which indicated an improvement in population inversion between Er:{sup 4}I{sub 11/2} and Er:{sup 4}I{sub 13/2}. Moreover, green up-conversion emission of Er{sup 3+} ion also showed a great improvement by co-doping 0.1 at% Nd{sup 3+}. Those great results were attributed to energy recycle from Er:{sup 4}I{sub 13/2} to Er:{sup 4}I{sub 11/2}. The energy recycle was mainly built by the two energy transfer between Er{sup 3+} and Nd{sup 3+} (one is from Er to Nd, another is in opposite way). So, Er/Nd co-doped yttrium lanthanum oxide transparent ceramic with Nd in low concentration can be considered as a promising laser material for ∼3 μm and up-conversion laser application. - Highlights: • (Er{sub 0.01}Nd{sub x}Y{sub 0.89-x}La{sub 0.1}){sub 2}O{sub 3} transparent ceramics were prepared. • The emission of 2.7 μm of Er{sup 3+} ion was significantly enhanced as x was 0.001. • The emission of 1.5 μm of Er{sup 3+} ion was suppressed greatly by co-doping Nd{sup 3+} ion. • Mechanism of Er–Nd energy transfer was discussed by the energy sketch.

CONCEPTUAL DESIGN ASSESSMENT FOR THE CO-FIRING OF BIO-REFINERY SUPPLIED LIGNIN PROJECT

International Nuclear Information System (INIS)

Ted Berglund; Jeffrey T. Ranney; Carol L. Babb; Jacqueline G. Broder

2002-01-01

The major aspects of this project are proceeding toward completion. Prior to this quarter, design criteria, tentative site selection, facility layout, and preliminary facility cost estimates were completed and issued. Processing of bio-solids was completed, providing material for the pilot operations. Pilot facility hydrolysis production has been completed to produce lignin for co-fire testing and the lignin fuel was washed and dewatered. Both the lignin and bio-solids fuel materials for co-fire testing were sent to the co-fire facility (EERC) for evaluation and co-firing. EERC has received coal typical of the fuel to the TVA-Colbert boilers. This material was used at EERC as baseline material and for mixing with the bio-fuel for combustion testing. All the combustion and fuel handling tests at EERC have been completed. During fuel preparation EERC reported no difficulties in fuel blending and handling. Preliminary co-fire test results indicate that the blending of lignin and bio-solids with the Colbert coal blend generally reduces NO(sub x) emissions, increases the reactivity of the coal, and increases the ash deposition rate on superheater surfaces. Deposits produced from the fuel blends, however, are more friable and hence easier to remove from tube surfaces relative to those produced from the baseline Colbert coal blend. The final co-fire testing report is being prepared at EERC and will be completed by the end of the second quarter of 2002. The TVA-Colbert facility has neared completion of the task to evaluate co-location of the Masada facility on the operation of the power generation facility. The TVA-Colbert fossil plant is fully capable of providing a reliable steam supply. The preferred steam supply connection points and steam pipeline routing have been identified. The environmental review of the pipeline routing has been completed and no major impacts have been identified. Detailed assessment of steam export impacts on the Colbert boiler system have been

The transition to farming and the ceramic trajectories in Western Eurasia. From ceramic figurines to vessels

Directory of Open Access Journals (Sweden)

Mihael Budja

2006-12-01

Full Text Available In Eurasia the invention of ceramic technology and production of fired-clay vessels has not necessarily been related to the dynamics of the transition to farming. The invention of ceramic technology in Europe was associated with female and animal figurine making in Gravettian technocomplex. The fired-clay vessels occurred first in hunter-gatherer contexts in Eastern Eurasia a millennia before the agriculture. The adoption of pottery making in Levant seems to correlate with the collapse of the ‘ritual economy’, social decentralisation and community fragmentation in the Levantine Pre-Pottery Neolithic. In South-eastern Europe the adoption of pottery making was closely associated with social, symbolic and ritual hunter-gatherers’ practices.

Formation of nanocomposite alumina-zirconia-silica ceramics

Czech Academy of Sciences Publication Activity Database

Chráska, Tomáš; Klementová, Mariana; Hostomský, Jiří

2007-01-01

Roč. 52, č. 4 (2007), s. 331-341 ISSN 0001-7043 R&D Projects: GA AV ČR KAN300430651 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z40320502 Keywords : TEM * sample preparation * plasma spraying * ceramic s Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass

Fabrication of lead-free piezoelectric Li2CO3-added (Ba,Ca)(Ti,Sn)O3 ceramics under controlled low oxygen partial pressure and their properties

Science.gov (United States)

Noritake, Kouta; Sakamoto, Wataru; Yuitoo, Isamu; Takeuchi, Teruaki; Hayashi, Koichiro; Yogo, Toshinobu

2018-02-01

Reduction-resistant lead-free (Ba,Ca)(Ti,Sn)O3 piezoceramics with high piezoelectric constants were fabricated by optimizing the amount of Li2CO3 added. Oxygen partial pressure was controlled during the sintering of (Ba,Ca)(Ti,Sn)O3 ceramics in a reducing atmosphere using H2-CO2 gas. Enhanced grain growth and a high-polarization state after poling treatment were achieved by adding Li2CO3. Optimizing the amount of Li2CO3 added to (Ba0.95Ca0.05)(Ti0.95Sn0.05)O3 ceramics sintered under a low oxygen partial pressure resulted in improved piezoelectric properties while maintaining the high sintered density. The prepared Li2CO3-added ceramic samples had homogeneous microstructures with a uniform dispersion of each major constituent element. However, the residual Li content in the 3 mol % Li2CO3-added (Ba0.95Ca0.05)(Ti0.95Sn0.05)O3 ceramics after sintering was less than 0.3 mol %. Sintered bodies of this ceramic prepared in a CO2 (1.5%)-H2 (0.3%)/Ar reducing atmosphere (PO2 = 10-8 atm at 1350 °C), exhibited sufficient electrical resistivity and a piezoelectric constant (d 33) exceeding 500 pC/N. The piezoelectric properties of this nonreducible ceramic were comparable or superior to those of the same ceramic sintered in air.

Enhanced green upconversion by controlled ceramization of Er3+–Yb3+ co-doped sodium niobium tellurite glass–ceramics for low temperature sensors

International Nuclear Information System (INIS)

Suresh Kumar, J.; Pavani, K.; Graça, M.P.F.; Soares, M.J.

2014-01-01

Highlights: • Upconversion luminescence improved in glass–ceramics compared to host glass. • Judd–Ofelt and radiative parameters calculated. • NIR decay curve results concur the results of improved luminescence. • Temperature dependent upconversion support the use of materials for sensors. - Abstract: Tellurite based glasses are well-known for their upconversion properties besides having a disadvantage of low mechanical strength dragging them away from practical applications. The present work deals with preparation of sodium niobium tellurite (SNT) glasses using melt quenching method, in which small quantities of boron and silicon in the form of oxides are added to improve their mechanical properties. Controlled heat treatment is performed to ceramize the prepared glasses based on the thermal data given by DTA. XRD and SEM profiles of the glass–ceramics which confirmed the formation of crystalline monoclinic Sodium Tellurium Niobium Oxide (Na 1.4 Nb 3 Te 4.9 O 18 ) phase (JCPDS card No. 04–011-7556). Upconversion measurements in the visible region were made for the prepared Er 3+ –Yb 3+ co-doped glasses and glass–ceramics with 980 nm laser excitation varying the laser power and concentration of Er 3+ ions. Results showed that the upconversion luminescence intensity was enhanced by ten times in SNT glass–ceramics compared to that in the SNT glasses. Decay curves give evidence of high performance of glass–ceramics compared to glasses due to ceramization and structural changes. Temperature dependent visible upconversion was performed to test the ability of efficient SNT glass–ceramic at low temperatures and variation of upconversion intensities was studied

The Characteristics of Peats and Co2 Emission Due to Fire in Industrial Plant Forests

Science.gov (United States)

Ratnaningsih, Ambar Tri; Rayahu Prasytaningsih, Sri

2017-12-01

Riau Province has a high threat to forest fire in peat soils, especially in industrial forest areas. The impact of fires will produce carbon (CO2) emissions in the atmosphere. The magnitude of carbon losses from the burning of peatlands can be estimated by knowing the characteristics of the fire peat and estimating CO2 emissions produced. The objectives of the study are to find out the characteristics of fire-burning peat, and to estimate carbon storage and CO2 emissions. The location of the research is in the area of industrial forest plantations located in Bengkalis Regency, Riau Province. The method used to measure peat carbon is the method of lost in ignation. The results showed that the research location has a peat depth of 600-800 cm which is considered very deep. The Peat fiber content ranges from 38 to 75, classified as hemic peat. The average bulk density was 0.253 gram cm-3 (0.087-0,896 gram cm-3). The soil ash content is 2.24% and the stored peat carbon stock with 8 meter peat thickness is 10723,69 ton ha-1. Forest fire was predicted to burn peat to a depth of 100 cm and produced CO2 emissions of 6,355,809 tons ha-1.

Microstructural analysis of clayey ceramic incorporated with fluorescent lamp glass

International Nuclear Information System (INIS)

Morais, A.S.C.; Caldas, T.C.C.; Pereira, P.S.; Monteiro, S.N.; Vieira, C.M.F.

2011-01-01

This study aims to evaluate the effect of the incorporation of glass powder fluorescent lamp, from a decontamination process, in the microstructure of clayey ceramic. Formulations were prepared with incorporation of the waste in amounts of up to 10 wt.% into the clayey body. Specimens were prepared by uniaxial mold-press at 20 MPa and then fired at 850 and 1050°C. After firing, the microstructure of the ceramics was evaluated by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the incorporation of glass powder into the clayey body changes the microstructure of the ceramics. (author)

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)

Freires, H.P.; Argonz, R.; Nogueira, R.E.F.Q.; Sasaki, J.M.; Sales, J.C.

2012-01-01

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)

Characterization of ceramic bodies to produce bricks from Campos Goytacazes, Brazil

International Nuclear Information System (INIS)

Almeida, L.L.P. de; Maia, F.S.; Petrucci, L.J.T.; Pessanha, E.M.; Paixao, L.P.

2010-01-01

This work has for objective to study comparatively the characteristics and technological properties of four typical ceramic bodies from the region of Campos dos Goytacazes-RJ used to fabricate red ceramics. The characterization techniques used were: X-ray fluorescence, X-ray diffraction, differential thermal analysis (DTA), thermogravimetric analysis (TGA) and dilatometry. Specimens were molded by extrusion and then fired at 750, 850 and 950 deg C. The evaluated firing properties were: linear shrinkage and water absorption. The results showed that the investigated ceramic bodies have similar chemical and mineralogical composition. It is also concluded that the bodies are adequate to produce bricks. (author)

Adsorption of 14CO2 by ceramic with the composition YBa2Cu3Ox

International Nuclear Information System (INIS)

Os'kina, T.E.; Soldatov, E.A.; Tret'yakov, Yu.D.; Kravchuk, A.I.; Eremina, E.A.

1989-01-01

The isotherms for 14 CO 2 absorption by a yttrium barium cuprate ceramic were determined as functions of stoichiometry, density, and carbon dioxide and water vapor tensions at room temperature. An empirical equation was found that related material absorption capacity to these factors over the parameter range investigated. The most significant factors and the effect of the interaction between carbon dioxide and water were identified. Data on absorption kinetics were used to compute the diffusion coefficient 14 CO 2 in YBa 2 Cu 3 O 6.45 , which equaled (1.87 ± 0.71)·10 -11 cm 2 /sec. The diffusion coefficient for water in this system was shown to be two orders of magnitude greater. This paper gives data on thermal decarbonization of the ceramic

Crack growth in thermally sprayed ceramic coatings

Czech Academy of Sciences Publication Activity Database

Kroupa, František; Náhlík, Luboš; Knésl, Zdeněk

2004-01-01

Roč. 49, č. 2 (2004), s. 149-168 ISSN 0001-7043 R&D Projects: GA ČR GP106/04/P084; GA ČR GA101/03/0331 Institutional research plan: CEZ:AV0Z2043910 Keywords : ceramic coatings, fracture mechanics, crack extension Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

Formulation, Pretreatment, and Densification Options to Improve Biomass Specifications for Co-Firing High Percentages with Coal

Energy Technology Data Exchange (ETDEWEB)

Jaya Shankar Tumuluru; J Richard Hess; Richard D. Boardman; Shahab Sokhansanj; Christopher T. Wright; Tyler L. Westover

2012-06-01

There is a growing interest internationally to use more biomass for power generation, given the potential for significant environmental benefits and long-term fuel sustainability. However, the use of biomass alone for power generation is subject to serious challenges, such as feedstock supply reliability, quality, and stability, as well as comparative cost, except in situations in which biomass is locally sourced. In most countries, only a limited biomass supply infrastructure exists. Alternatively, co-firing biomass alongwith coal offers several advantages; these include reducing challenges related to biomass quality, buffering the system against insufficient feedstock quantity, and mitigating the costs of adapting existing coal power plants to feed biomass exclusively. There are some technical constraints, such as low heating values, low bulk density, and grindability or size-reduction challenges, as well as higher moisture, volatiles, and ash content, which limit the co-firing ratios in direct and indirect co-firing. To achieve successful co-firing of biomass with coal, biomass feedstock specifications must be established to direct pretreatment options in order to modify biomass materials into a format that is more compatible with coal co-firing. The impacts on particle transport systems, flame stability, pollutant formation, and boiler-tube fouling/corrosion must also be minimized by setting feedstock specifications, which may include developing new feedstock composition by formulation or blending. Some of the issues, like feeding, co-milling, and fouling, can be overcome by pretreatment methods including washing/leaching, steam explosion, hydrothermal carbonization, and torrefaction, and densification methods such as pelletizing and briquetting. Integrating formulation, pretreatment, and densification will help to overcome issues related to physical and chemical composition, storage, and logistics to successfully co-fire higher percentages of biomass ( > 40

Opportunities for Decarbonizing Existing U.S. Coal-Fired Power Plants via CO2 Capture, Utilization and Storage.

Science.gov (United States)

Zhai, Haibo; Ou, Yang; Rubin, Edward S

2015-07-07

This study employs a power plant modeling tool to explore the feasibility of reducing unit-level emission rates of CO2 by 30% by retrofitting carbon capture, utilization, and storage (CCUS) to existing U.S. coal-fired electric generating units (EGUs). Our goal is to identify feasible EGUs and their key attributes. The results indicate that for about 60 gigawatts of the existing coal-fired capacity, the implementation of partial CO2 capture appears feasible, though its cost is highly dependent on the unit characteristics and fuel prices. Auxiliary gas-fired boilers can be employed to power a carbon capture process without significant increases in the cost of electricity generation. A complementary CO2 emission trading program can provide additional economic incentives for the deployment of CCS with 90% CO2 capture. Selling and utilizing the captured CO2 product for enhanced oil recovery can further accelerate CCUS deployment and also help reinforce a CO2 emission trading market. These efforts would allow existing coal-fired EGUs to continue to provide a significant share of the U.S. electricity demand.

Comparison of the bond strength of ceramics to Co-Cr alloys made by casting and selective laser melting.

Science.gov (United States)

Lawaf, Shirin; Nasermostofi, Shahbaz; Afradeh, Mahtasadat; Azizi, Arash

2017-02-01

Considering the importance of metal-ceramic bond, the present study aimed to compare the bond strength of ceramics to cobalt-chrome (Co-Cr) alloys made by casting and selective laser melting (SLM). In this in-vitro experimental study, two sample groups were prepared, with one group comprising of 10 Co-Cr metal frameworks fabricated by SLM method and the other of 10 Co-Cr metal frameworks fabricated by lost wax cast method with the dimensions of 0.5 × 3 × 25 mm (following ISO standard 9693). Porcelain with the thickness of 1.1 mm was applied on a 3 × 8-mm central rectangular area of each sample. Afterwards, bond strengths of the samples were assessed with a Universal Testing Machine. Statistical analysis was performed with Kolmogorov-Smirnov test and T-test. Bond strength in the conventionally cast group equaled 74.94 ± 16.06 MPa, while in SLM group, it equaled 69.02 ± 5.77 MPa. The difference was not statistically significant ( P ≤ .05). The results indicated that the bond strengths between ceramic and Co-Cr alloys made by casting and SLM methods were not statistically different.

GREENHOUSE GAS EMISSIONS CONTROL BY OXYGEN FIRING IN CIRCULATING FLUIDIZED BED BOILERS: PHASE II--PILOT SCALE TESTING AND UPDATED PERFORMANCE AND ECONOMICS FOR OXYGEN FIRED CFB WITH CO2 CAPTURE

Energy Technology Data Exchange (ETDEWEB)

Nsakala ya Nsakala; Gregory N. Liljedahl; David G. Turek

2004-10-27

Because fossil fuel fired power plants are among the largest and most concentrated producers of CO{sub 2} emissions, recovery and sequestration of CO{sub 2} from the flue gas of such plants has been identified as one of the primary means for reducing anthropogenic CO{sub 2} emissions. In this Phase II study, ALSTOM Power Inc. (ALSTOM) has investigated one promising near-term coal fired power plant configuration designed to capture CO{sub 2} from effluent gas streams for sequestration. Burning fossil fuels in mixtures of oxygen and recirculated flue gas (made principally of CO{sub 2}) essentially eliminates the presence of atmospheric nitrogen in the flue gas. The resulting flue gas is comprised primarily of CO{sub 2}, along with some moisture, nitrogen, oxygen, and trace gases like SO{sub 2} and NO{sub x}. Oxygen firing in utility scale Pulverized Coal (PC) fired boilers has been shown to be a more economical method for CO{sub 2} capture than amine scrubbing (Bozzuto, et al., 2001). Additionally, oxygen firing in Circulating Fluid Bed Boilers (CFB's) can be more economical than in PC or Stoker firing, because recirculated gas flow can be reduced significantly. Oxygen-fired PC and Stoker units require large quantities of recirculated flue gas to maintain acceptable furnace temperatures. Oxygen-fired CFB units, on the other hand, can accomplish this by additional cooling of recirculated solids. The reduced recirculated gas flow with CFB plants results in significant Boiler Island cost savings resulting from reduced component The overall objective of the Phase II workscope, which is the subject of this report, is to generate a refined technical and economic evaluation of the Oxygen fired CFB case (Case-2 from Phase I) utilizing the information learned from pilot-scale testing of this concept. The objective of the pilot-scale testing was to generate detailed technical data needed to establish advanced CFB design requirements and performance when firing coals and

Mechanical properties of ceramics

CERN Document Server

Pelleg, Joshua

2014-01-01

This book discusses the mechanical properties of ceramics and aims to provide both a solid background for undergraduate students, as well as serving as a text to bring practicing engineers up to date with the latest developments in this topic so they can use and apply these to their actual engineering work.  Generally, ceramics are made by moistening a mixture of clays, casting it into desired shapes and then firing it to a high temperature, a process known as 'vitrification'. The relatively late development of metallurgy was contingent on the availability of ceramics and the know-how to mold them into the appropriate forms. Because of the characteristics of ceramics, they offer great advantages over metals in specific applications in which hardness, wear resistance and chemical stability at high temperatures are essential. Clearly, modern ceramics manufacturing has come a long way from the early clay-processing fabrication method, and the last two decades have seen the development of sophisticated technique...

Ceramic on ceramic arthroplasty of the hip: new materials confirm appropriate use in young patients.

Science.gov (United States)

Sentuerk, U; von Roth, P; Perka, C

2016-01-01

The leading indication for revision total hip arthroplasty (THA) remains aseptic loosening owing to wear. The younger, more active patients currently undergoing THA present unprecedented demands on the bearings. Ceramic-on-ceramic (CoC) bearings have consistently shown the lowest rates of wear. The recent advances, especially involving alumina/zirconia composite ceramic, have led to substantial improvements and good results in vitro. Alumina/zirconia composite ceramics are extremely hard, scratch resistant and biocompatible. They offer a low co-efficient of friction and superior lubrication and lower rates of wear compared with other bearings. The major disadvantage is the risk of fracture of the ceramic. The new composite ceramic has reduced the risk of fracture of the femoral head to 0.002%. The risk of fracture of the liner is slightly higher (0.02%). Assuming that the components are introduced without impingement, CoC bearings have major advantages over other bearings. Owing to the superior hardness, they produce less third body wear and are less vulnerable to intra-operative damage. The improved tribology means that CoC bearings are an excellent choice for young, active patients requiring THA. ©2016 The British Editorial Society of Bone & Joint Surgery.

Thermo-mechanical properties of mullite/zirconia reinforced alumina ceramic composites

International Nuclear Information System (INIS)

Wahsh, M.M.S.; Khattab, R.M.; Awaad, M.

2012-01-01

Highlights: ► Alumina–mullite–zirconia ceramic composites were prepared from alumina and zircon. ► Constant amount of magnesia was added as a sintering aid. ► Mechanical properties were enhanced with increasing of zircon up to 30.52 mass%. ► All of ceramic composites were achieved excellent thermal shock resistance. -- Abstract: Alumina–mullite–zirconia ceramic composites were prepared by reaction bonding of alumina and zircon mixtures after firing at different temperatures 1300°, 1400° and 1500 °C. Constant amount of magnesia was added as a sintering aid. The technological parameters of the sintered ceramic composites, i.e. the mechanical properties and densification parameter as well as thermal shock resistance, have been investigated. The phase compositions and microstructure of the sintered ceramic composites were detected by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results indicated that alumina–mullite–zirconia ceramic composites fired at 1500 °C for 2 h were achieved a good densification parameters and mechanical properties as well as excellent thermal shock resistance. In addition, these ceramic composites were showed enhancement in Vickers’ microhardness and fracture toughness values.

Effects of repeated firing on the marginal accuracy of Co-Cr copings fabricated by selective laser melting.

Science.gov (United States)

Zeng, Li; Zhang, Yong; Liu, Zheng; Wei, Bin

2015-02-01

Selective laser melting (SLM) is a technique used to fabricate Co-Cr dental restorations; however, because marginal accuracy is important for the long-term success of restorations, the marginal accuracy of SLM after repeated firings must be considered. The purpose of this study was to evaluate the marginal accuracy of dental Co-Cr alloy copings fabricated by SLM and to investigate the effects of repeated firing on the marginal fit of these copings. SLM-fabricated and cast Co-Cr alloy copings (n=15) were prepared for a zirconia die. The marginal gap widths of each group were evaluated with a silicone replica technique after the first, third, fifth, and seventh firing cycle. The thickness of the reference point was measured with a stereomicroscope with ×100 magnification. Analysis of variance was used to evaluate the effect of repeated firing on the marginal accuracy of the 2 alloys. The Student t test was used to compare the marginal gap widths of the SLM-fabricated and cast Co-Cr alloy copings after repeated firing (α=.05). The marginal gap width values between the 2 groups at all firing periods were statistically significant (P.05). The SLM copings demonstrated superior marginal accuracy at all firings. Repeated firing had no significant influence on the marginal accuracy of both copings, and the marginal fit of both copings after repeated firing was within a clinically acceptable range. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

CoO-doped MgO-Al2O3-SiO2-colored transparent glass-ceramics with high crystallinity

Science.gov (United States)

Tang, Wufu; Zhang, Qian; Luo, Zhiwei; Yu, Jingbo; Gao, Xianglong; Li, Yunxing; Lu, Anxian

2018-02-01

To obtain CoO-doped MgO-Al2O3-SiO2 (MAS)-colored transparent glass-ceramics with high crystallinity, the glass with the composition 21MgO-21Al2O3-54SiO2-4B2O3-0.2CoO (in mol %) was prepared by conventional melt quenching technique and subsequently thermal treated at several temperatures. The crystallization behavior of the glass, the precipitated crystalline phases and crystallinity were analyzed by X-ray diffraction (XRD). The microstructure of the glass-ceramics was characterized by field emission scanning electron microscopy (FSEM). The transmittance of glass-ceramic was measured by UV spectrophotometer. The results show that a large amount of α-cordierite (indianite) with nano-size was precipitated from the glass matrix after treatment at 1020 °C for 3 h. The crystallinity of the transparent glass-ceramic reached up to 97%. Meanwhile, the transmittance of the glass-ceramic was 74% at 400 nm with a complex absorption band from 450 nm to 700 nm. In addition, this colored transparent glass-ceramic possessed lower density (2.469 g/cm3), lower thermal expansion coefficient (1.822 × 10-6 /℃), higher Vickers hardness (9.1 GPa) and higher bending strength (198 MPa) than parent glass.

Co-firing behavior of ZnTiO3-TiO2 dielectrics/hexagonal ferrite composites for multi-layer LC filters

International Nuclear Information System (INIS)

Wang Mao; Zhou Ji; Yue Zhenxing; Li Longtu; Gui Zhilun

2003-01-01

The low-temperature co-firing compatibility between ferrite and dielectric materials is the key issue in the production process of multi-layer chip LC filters. This paper presents the co-firing behavior and interfacial diffusion of ZnTiO 3 -TiO 2 dielectric/Co 2 Z hexagonal ferrite multi-layer composites. It has been testified that proper constitutional modification is feasible to diminish co-firing mismatch and enhance co-firing compatibility. Interfacial reactions occur at the interface, which can strengthen combinations between ferrite layers and dielectric layers. Titanium and barium tend to concentrate at the interface; iron and zinc have a wide diffusion range

SnO2*CoO ceramic obtained by microwave sintering

International Nuclear Information System (INIS)

Bordignon, M.A.N; Moura, F.; Zaghete, M.A.; Varela, J.A.; Perazolli, L.

2009-01-01

This work consists in the sintering study of CoO doped SnO 2 using microwave sintering oven and silicon carbide as a susceptor. The powders were obtained by dry oxides mixture and conformed in cylindrical shapes with 6mmx8mm and green density to 60%. Then the compacts were sintering up to 1.050 deg C, using heating rate of 50 deg C/min and isotherm up to 30min. The densities obtained were above 95% for both techniques. It was observed that occurred a temperature reducing of 400 deg C and time reducing of 210min to obtain the same densities, when was used the microwave oven without the phenomena of thermal runaway. So the sintered compacts were accomplished using DRX and SEM. It was made the electrical characterization (current x voltage) and it was found to have great potential in the production of dense ceramic-based SnO 2 with low resistivity to obtain electro-ceramic devices. (author)

Metal-ceramic bond strength of Co-Cr alloy fabricated by selective laser melting.

Science.gov (United States)

Xiang, Nan; Xin, Xian-Zhen; Chen, Jie; Wei, Bin

2012-06-01

This study was to evaluated the metal-ceramic bond strength of a Co-Cr dental alloy prepared using a selective laser melting (SLM) technique. Two groups comprised of twenty Co-Cr metal bars each were prepared using either a SLM or traditional lost-wax casting method. Ten bars from each group were moulded into standard ISO 9693:1999 dimensions of 25 mm × 3 mm × 0.5 mm with 1.1 mm of porcelain fused onto an 8 mm × 3 mm rectangular area in the centre of each bar. Metal-ceramic bonding was assessed using a three-point bending test. Fracture mode analysis and area fraction of adherence porcelain (AFAP) were determined by measuring Si content of specimens by SEM/EDS. Student's t-test within the groups demonstrated no significant difference for the mean bond strength between the SLM and traditional cast sample groups. While SEM/EDS analysis indicated a mixed fracture mode on the debonding interface of both the SLM and the cast groups, the SLM group showed significantly more porcelain adherence than the control group (p<0.05). The SLM metal-ceramic system exhibited a bonding strength that exceeds the requirement of ISO 9691:1999(E) and it even showed a better behaviour in porcelain adherence test comparable to traditional cast methods. Copyright © 2012 Elsevier Ltd. All rights reserved.

Operational experiences of (in)direct co-combustion in coal and gas fired power plants in Europe

International Nuclear Information System (INIS)

Van Ree, R.; Korbee, R.; Meijer, R.; Konings, T.; Van Aart, F.

2001-02-01

The operational experiences of direct and indirect co-combustion of biomass/waste in European coal and natural gas fired power plants are addressed. The operational experiences of mainly Dutch direct co-combustion activities in coal fired power plants are discussed; whereas an overview of European indirect co-combustion activities is presented. The technical, environmental, and economic feasibility of different indirect co-combustion concepts (i.e. upstream gasification, pyrolysis, combustion with steam-side integration) is investigated, and the results are compared with the economic preferable concept of direct co-combustion. Main technical constraints that limit the co-combustion capacity of biomass/waste in conventional coal fired power plants are: the grindability of the biomass/coal blend, the capacity of available unit components, and the danger of severe slagging, fouling, corrosion and erosion. The main environmental constraints that have to be taken into account are the quality of produced solid waste streams (fly ash, bottom ash, gypsum) and the applicable air emission regulations. 6 refs

Microstructural characterization of ceramic floor tiles with the incorporation of wastes from ceramic tile industries

Directory of Open Access Journals (Sweden)

Carmeane Effting

2010-09-01

Full Text Available Ceramic floor tiles are widely used in buildings. 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 introduction of the crustiness surface on the ceramic floor tiles interfere in the contact temperature and also it can be an strategy to obtain ceramic tiles more comfortable. In this work, porous ceramic tiles were obtained by pressing an industrial atomized ceramic powder incorporated with refractory raw material (residue from porcelainized stoneware tile polishing and changing firing temperature. Raw materials and obtained compacted samples were evaluated by chemical analysis, scanning electron microscopy (SEM, energy-dispersive spectrometry (EDS, thermogravimetric analysis (TGA, and differential thermal analysis (DTA. Thermal (thermal conductivity and effusivity and physical (porosity measurements were also evaluated.

Influence of sintering temperature in red ceramic with addition of mill scale

International Nuclear Information System (INIS)

Arnt, A.B.C.; Rocha, M.R.; Bernardin, A.M.; Meller, J.G.

2010-01-01

This study aimed to evaluate the influence of sintering temperature in a red ceramic body with the addition of mill scale. This residue consists of oxides of iron had to replace the function of pigments used in ceramic materials. After chemical characterization, by X-ray diffraction, X-ray fluorescence and scanning electron microscopy, this residue was added at a rate of 5% in commercial ceramic past. The formulations were subjected to different burn temperatures of around 950 deg C, 1000 deg C and 1200 deg C. The formulations were evaluated for physical loss to fire, linear firing shrinkage, water absorption and flexural strength by 3 and intensity of tone. The results indicate that the different firing temperatures influence the strength and stability of tone in the formulations tested. (author)

Co-firing of Coal with Biomass and Waste in Full-scale Suspension-fired Boilers

DEFF Research Database (Denmark)

Dam-Johansen, Kim; Jappe Frandsen, Flemming; Jensen, Peter Arendt

2013-01-01

and boiler manufacturers to optimize design and operation and minimize cost and environmental impact using alternative fuels in suspension fired boilers. Our contribution has been made via a combination of full-scale measuring campaigns, pilot-scale studies, lab-scale measurements and modeling tools....... The research conducted has addressed many issues important for co-firing, i.e. fuel processing, ash induced boiler deposit formation and corrosion, boiler chamber fuel conversion and emission formation, influence on flue gas cleaning equipment and the utilization of residual products. This paper provides...... research has provided results with implications for operation of milling and burner equipment, appropriate fuel mixing strategies, minimization of ash deposit formation and corrosion, minimization of NO formation, appropriate operation of SCR catalyst equipment and utilization of residual products...

Evaluation of metal-ceramic bond characteristics of three dental Co-Cr alloys prepared with different fabrication techniques.

Science.gov (United States)

Wang, Hongmei; Feng, Qing; Li, Ning; Xu, Sheng

2016-12-01

Limited information is available regarding the metal-ceramic bond strength of dental Co-Cr alloys fabricated by casting (CAST), computer numerical control (CNC) milling, and selective laser melting (SLM). The purpose of this in vitro study was to evaluate the metal-ceramic bond characteristics of 3 dental Co-Cr alloys fabricated by casting, computer numerical control milling, and selective laser melting techniques using the 3-point bend test (International Organization for Standardization [ISO] standard 9693). Forty-five specimens (25×3×0.5 mm) made of dental Co-Cr alloys were prepared by CAST, CNC milling, and SLM techniques. The morphology of the oxidation surface of metal specimens was evaluated by scanning electron microscopy (SEM). After porcelain application, the interfacial characterization was evaluated by SEM equipped with energy-dispersive spectrometry (EDS) analysis, and the metal-ceramic bond strength was assessed with the 3-point bend test. Failure type and elemental composition on the debonding interface were assessed by SEM/EDS. The bond strength was statistically analyzed by 1-way ANOVA and Tukey honest significant difference test (α=.05). The oxidation surfaces of the CAST, CNC, and SLM groups were different. They were porous in the CAST group but compact and irregular in the CNC and SLM groups. The metal-ceramic interfaces of the SLM and CNC groups showed excellent combination compared with those of the CAST group. The bond strength was 37.7 ±6.5 MPa for CAST, 43.3 ±9.2 MPa for CNC, and 46.8 ±5.1 MPa for the SLM group. Statistically significant differences were found among the 3 groups tested (P=.028). The debonding surfaces of all specimens exhibited cohesive failure mode. The oxidation surface morphologies and thicknesses of dental Co-Cr alloys are dependent on the different fabrication techniques used. The bond strength of all 3 groups exceed the minimum acceptable value of 25 MPa recommended by ISO 9693; hence, dental Co-Cr alloy

Durability of feldspathic veneering ceramic on glass-infiltrated alumina ceramics after long-term thermocycling.

Science.gov (United States)

Mesquita, A M M; Ozcan, M; Souza, R O A; Kojima, A N; Nishioka, R S; Kimpara, E T; Bottino, M A

2010-01-01

This study compared the bond strength durability of a feldspathic veneering ceramic to glass-infiltrated reinforced ceramics in dry and aged conditions. Disc shaped (thickness: 4 mm, diameter: 4 mm) of glass-infiltrated alumina (In-Ceram Alumina) and glass-infiltrated alumina reinforced by zirconia (In-Ceram Zirconia) core ceramic specimens (N=48, N=12 per groups) were constructed according to the manufacturers' recommendations. Veneering ceramic (VITA VM7) was fired onto the core ceramics using a mold. The core-veneering ceramic assemblies were randomly divided into two conditions and tested either immediately after specimen preparation (Dry) or following 30000 thermocycling (5-55 ºC±1; dwell time: 30 seconds). Shear bond strength test was performed in a universal testing machine (cross-head speed: 1 mm/min). Failure modes were analyzed using optical microscope (x20). The bond strength data (MPa) were analyzed using ANOVA (α=0.05). Thermocycling did not decrease the bond strength results for both In-Ceram Alumina (30.6±8.2 MPa; P=0.2053) and In-Ceram zirconia (32.6±9 MPa; P=0.3987) core ceramic-feldspathic veneering ceramic combinations when compared to non-aged conditions (28.1±6.4 MPa, 29.7±7.3 MPa, respectively). There were also no significant differences between adhesion of the veneering ceramic to either In-Ceram Alumina or In-Ceram Zirconia ceramics (P=0.3289). Failure types were predominantly a mixture of adhesive failure between the veneering and the core ceramic together with cohesive fracture of the veneering ceramic. Long-term thermocycling aging conditions did not impair the adhesion of the veneering ceramic to the glass-infiltrated alumina core ceramics tested.

Study on Tribological Properties of CoCrMo Alloys against Metals and Ceramics as Bearing Materials for Artificial Cervical Disc

Science.gov (United States)

Xiang, Dingding; Song, Jian; Wang, Song; Liao, Zhenhua; Liu, Yuhong; Tyagi, Rajnesh; Liu, Weiqiang

2018-02-01

CoCrMo alloys are believed to be a kind of potential material for artificial cervical disc. However, the tribological properties of CoCrMo alloys against different metals and ceramics are not systematically studied. In this study, the tribological behaviors of CoCrMo alloys against metals (316L, Ti6Al4V) and ceramics (Si3N4, ZrO2) were focused under dry friction and 25 wt.% newborn calf serum (NCS)-lubricated conditions using a ball-on-disc apparatus under reciprocating motion. The microstructure, composition and hardness of CoCrMo alloys were characterized using x-ray diffraction, scanning electron microscopy (SEM) and hardness testers, respectively. The contact angles of the CoCrMo alloys with deionized water and 25 wt.% NCS were measured by the OCA contact angle measuring instrument. The maximum wear width, wear depth and wear volume were measured by three-dimensional white light interference. The morphology and the EDX analysis of the wear marks on CoCrMo alloys were examined by SEM to determine the basic mechanism of friction and wear. The dominant wear mechanism in dry friction for CoCrMo alloys against all pairings was severe abrasive wear, accompanied with a lot of material transfer. Under 25 wt.% NCS-lubricated condition, the wear mechanism for CoCrMo alloys against ceramics (Si3N4, ZrO2) was also mainly severe abrasive wear. However, severe abrasive wear and electrochemical corrosion occurred for the CoCrMo-316L pairing under lubrication. Severe abrasive wear, adhesive wear and electrochemical corrosion occurred for the CoCrMo-Ti6Al4V pairing under lubrication. According to the results, the tribological properties of CoCrMo alloys against ceramics were better than those against metals. The CoCrMo-ZrO2 pairing displayed the best tribological behaviors and could be taken as a potential candidate bearing material for artificial cervical disc.

Early Pottery Making in Northern Coastal Peru. Part II: Field Firing Experiments

International Nuclear Information System (INIS)

Shimada, I.; Goldstein, D.; Sosa, J.; Wagner, U.

2003-01-01

We present data from three seasons of experimental field work designed to recreate ancient Andean coastal ceramic firing techniques. Based on the recent discovery of two different archaeological ceramic production sites in the La Leche river valley of northern coastal Peru, the opportunity arose to apply Moessbauer spectroscopy and other analytical methods to reconstruct ancient firing procedures. Two sets of firings took place in 1993 and 1997 in Batan Grande using a partially restored Formative kiln from about 800 BC, local hardwood and cow dung as fuel. A third experiment followed in 2000 after the discovery of a Middle Sican ceramics workshop in use between ca. AD 950 and 1050 at Huaca Sialupe, where an exact replica of an ancient kiln was built from local clay, and fired with local wood and cow dung. Additionally, inverted urns found at Huaca Sialupe were tested for their potential use as furnaces for metal working. Moessbauer spectroscopy was used to compare the physical and chemical state of specimens produced in the field experiments with ancient ceramics and with specimens produced in controlled laboratory experiments.

The Integration Method of Ceramic Arts in the Product Design

Science.gov (United States)

Shuxin, Wang

2018-03-01

As one of the four ancient civilization countries, the firing technology of ceramic invented by China has made a great contribution to the progress and development of human society. In modern life, even the development of technology still needs the ceramics, there are large number of artists who take the ceramics as carrier active in the field of contemporary art. The ceramics can be seen everywhere in our daily life, this paper mainly discusses the integration means of ceramic art in the product design.

Glass-ceramic coating material for the CO2 laser based sintering of thin films as caries and erosion protection.

Science.gov (United States)

Bilandžić, Marin Dean; Wollgarten, Susanne; Stollenwerk, Jochen; Poprawe, Reinhart; Esteves-Oliveira, Marcella; Fischer, Horst

2017-09-01

The established method of fissure-sealing using polymeric coating materials exhibits limitations on the long-term. Here, we present a novel technique with the potential to protect susceptible teeth against caries and erosion. We hypothesized that a tailored glass-ceramic material could be sprayed onto enamel-like substrates to create superior adhesion properties after sintering by a CO 2 laser beam. A powdered dental glass-ceramic material from the system SiO 2 -Na 2 O-K 2 O-CaO-Al 2 O 3 -MgO was adjusted with individual properties suitable for a spray coating process. The material was characterized using X-ray fluorescence analysis (XRF), heating microscopy, dilatometry, scanning electron microscopy (SEM), grain size analysis, biaxial flexural strength measurements, fourier transform infrared spectroscopy (FTIR), and gas pycnometry. Three different groups of samples (each n=10) where prepared: Group A, powder pressed glass-ceramic coating material; Group B, sintered hydroxyapatite specimens; and Group C, enamel specimens (prepared from bovine teeth). Group B and C where spray coated with glass-ceramic powder. All specimens were heat treated using a CO 2 laser beam process. Cross-sections of the laser-sintered specimens were analyzed using laser scanning microscopy (LSM), energy dispersive X-ray analysis (EDX), and SEM. The developed glass-ceramic material (grain size d50=13.1mm, coefficient of thermal expansion (CTE)=13.310 -6 /K) could be spray coated on all tested substrates (mean thickness=160μm). FTIR analysis confirmed an absorption of the laser energy up to 95%. The powdered glass-ceramic material was successfully densely sintered in all sample groups. The coating interface investigation by SEM and EDX proved atomic diffusion and adhesion of the glass-ceramic material to hydroxyapatite and to dental enamel. A glass-ceramic material with suitable absorption properties was successfully sprayed and laser-sintered in thin films on hydroxyapatite as well as on

Tunable bandpass filter based on partially magnetized ferrite LTCC with embedded windings for SoP applications

KAUST Repository

Arabi, Eyad A.

2015-01-01

Tunable filters that are based on ferrite materials often require large and bulky electromagnets. In this work, we present a tunable filter in the Ku-band, which is realized in multilayer ferrite LTCC substrate with embedded bias windings, thus negating the need of a large electromagnet. Also, because of the embedded windings, the bias fields are not lost at the air-substrate interface and therefore the field and current requirements are reduced by an order of magnitude as compared to the previously reported filters. A simulation strategy that uses full permeability tensor with arbitrarily directed magnetic fields has been used to model the filter on a partially magnetized ferrite substrate. Special attention has also been paid to approximate the non-uniform magneto-static fields produced by the embedded windings. The complete design is implemented in 10 layers of ferrite LTCC, making it the first magnetically tunable filter with embedded windings and extremely small size [(5 × 5 × 1.1)mm3]. The filter demonstrates a measured tunability of 4% and an insertion loss of 2.3 dB. With the small form factor, embedded windings, and low bias requirements, the design is highly suitable for compact and tunable SoP applications.

Tensile Behaviour of Open Cell Ceramic Foams

Czech Academy of Sciences Publication Activity Database

Řehořek, Lukáš; Dlouhý, Ivo; Chlup, Zdeněk

2009-01-01

Roč. 53, č. 4 (2009), s. 237-241 ISSN 0862-5468 R&D Projects: GA ČR GA101/09/1821; GA ČR GD106/09/H035 Institutional research plan: CEZ:AV0Z20410507 Keywords : Tensile test * Ceramics foam * Open porosity * Tensile strength Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.649, year: 2009

Tensile properties of open cell ceramic foams

Czech Academy of Sciences Publication Activity Database

Bertolla, Luca; Dlouhý, Ivo; Řehořek, Lukáš; Chlup, Zdeněk

2013-01-01

Roč. 3, č. 1 (2013), s. 106-113 ISSN 1338-1660. [FRACTOGRAPHY 2012. Stará Lesná, 21.10.2012-24.10.2012] R&D Projects: GA ČR(CZ) GA101/09/1821 EU Projects: European Commission(XE) 264526 - GLACERCO Institutional support: RVO:68081723 Keywords : tension test * cellular materials * ceramics Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

Waste Not, Want Not: An Inexpensive Glass-Ceramic from Waste

Czech Academy of Sciences Publication Activity Database

Wu, J. P.; Rawlings, R. D.; Boccaccini, A. R.; Dlouhý, Ivo; Chlup, Zdeněk

2006-01-01

Roč. 85, č. 5 (2006), s. 29-32 ISSN 0002-7812 R&D Projects: GA ČR(CZ) GA106/05/0495 Institutional research plan: CEZ:AV0Z20410507 Keywords : glass ceramic s * fracture toughness * flexural strength Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass Impact factor: 0.210, year: 2006 http://www. ceramic bulletin.org/2006-05.asp

Thermal Pretreatment of Wood for Co-gasification/co-firing of Biomass and Coal

Energy Technology Data Exchange (ETDEWEB)

Wang, Ping [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Howard, Bret [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Hedges, Sheila [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Morreale, Bryan [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Van Essendelft, Dirk [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Berry, David [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

2013-10-29

Utilization of biomass as a co-feed in coal and biomass co-firing and co-gasification requires size reduction of the biomass. Reducing biomass to below 0.2 mm without pretreatment is difficult and costly because biomass is fibrous and compressible. Torrefaction is a promising thermal pretreatment process and has the advantages of increasing energy density, improving grindability, producing fuels with more homogenous compositions and hydrophobic behavior. Temperature is the most important factor for the torrefaction process. Biomass grindability is related to cell wall structure, thickness and composition. Thermal treatment such as torrefaction can cause chemical changes that significantly affect the strength of biomass. The objectives of this study are to understand the mechanism by which torrefaction improves the grindability of biomass and discuss suitable temperatures for thermal pretreatment for co-gasification/co-firing of biomass and coal. Wild cherry wood was selected as the model for this study. Samples were prepared by sawing a single tangential section from the heartwood and cutting it into eleven pieces. The samples were consecutively heated at 220, 260, 300, 350, 450 and 550⁰C for 0.5 hr under flowing nitrogen in a tube furnace. Untreated and treated samples were characterized for physical properties (color, dimensions and weight), microstructural changes by SEM, and cell wall composition changes and thermal behaviors by TGA and DSC. The morphology of the wood remained intact through the treatment range but the cell walls were thinner. Thermal treatments were observed to decompose the cell wall components. Hemicellulose decomposed over the range of ~200 to 300⁰C and resulted in weakening of the cell walls and subsequently improved grindability. Furthermore, wood samples treated above 300⁰C lost more than 39% in mass. Therefore, thermal pretreatment above the hemicelluloses decomposition temperature but below 300⁰C is probably sufficient to

Barium titanate nanometric polycrystalline ceramics fired by spark plasma sintering.

Czech Academy of Sciences Publication Activity Database

Ctibor, Pavel; Sedláček, J.; Ryukhtin, Vasyl; Cinert, Jakub; Lukáč, František

2016-01-01

Roč. 42, č. 14 (2016), s. 15989-15993 ISSN 0272-8842 R&D Projects: GA ČR GB14-36566G; GA MŠk LM2015056 Institutional support: RVO:61389021 ; RVO:61389005 Keywords : BaTiO3 * Spark plasma sintering * Electrical properties Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass; JH - Ceramics, Fire-Resistant Materials and Glass (UJF-V) Impact factor: 2.986, year: 2016 http://www.sciencedirect.com/science/article/pii/S0272884216311695

Characterization and evaluation of ceramic properties of clay used in structural ceramics

International Nuclear Information System (INIS)

Savazzini-Reis, A.; Della-Sagrillo, V.P.; Valenzuela-Diaz, F.R.

2016-01-01

The Brazilian red ceramic industry monthly consumes about 10.3 million tons of clay, its main raw material. In most potteries, characterization of the clay is made empirically, which can result in tiles and blocks not according to standards. This sense, this paper aims to characterize clays used in the manufacturing of red ceramic products in factory located in Colatina-ES, which appears as a ceramic pole with about twenty small and midsize industries. The clays were characterized by: Xray fluorescence, X-ray diffraction, thermal analysis (TG/DSC), granulometry and Atterberg limits. Specimens of clay and mixture containing four clays were shaped. Specimens were shaped, dried at 110°C, and burned in a kiln for 24 h. The ceramics and mechanical characteristics were evaluated: flexural strength, water absorption, apparent porosity, apparent specific mass and shrinkage by drying and firing. The characterization showed that kaolinitic clay presents high plasticity, but high porosity. The mixture formed by the four clays does not meet the requirements of the Brazilian standard clays for red ceramic. (author)

Fabrication of a 40-inch diameter ceramic to metal seal for PLT

International Nuclear Information System (INIS)

Lewin, G.; Mullaney, D.

1976-01-01

The design and fabrication details for the ceramic to metal seal for PLT are presented. The method used for the successful casting and firing of the 90% Al 2 O 3 ceramic body and the subsequent grinding and brazing of the ceramic to 430 S.S. are discussed

Nonlinear Stress-Strain Behavior of Plasma Sprayed Ceramic Coatings

Czech Academy of Sciences Publication Activity Database

Nohava, Jiří; Kroupa, František

2005-01-01

Roč. 50, č. 3 (2005), s. 251-262 ISSN 0001-7043 R&D Projects: GA AV ČR KSK1010104 Institutional research plan: CEZ:AV0Z20430508 Keywords : plasma spraying * ceramic coatings * Young’s modulus * nonlinear behavior * microcracks Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

A Greenhouse Gas Balance of Electricity Production from Co-firing Palm Oil Products from Malaysia

International Nuclear Information System (INIS)

Wicke, B.; Dornburg, V.; Faaij, A.; Junginger, M.

2007-05-01

The Netherlands imports significant quantities of biomass for energy production, among which palm oil has been used increasingly for co-firing in existing gas-fired power plants for renewable electricity production. Imported biomass, however, can not simply be considered a sustainable energy source. The production and removal of biomass in other places in the world result in ecological, land-use and socio-economic impacts and in GHG emissions (e.g. for transportation). As a result of the sustainability discussions, the Cramer Commission in the Netherlands has formulated (draft) criteria and indicators for sustainable biomass production. This study develops a detailed methodology for determining the GHG balance of co-firing palm oil products in the Netherlands based on the Cramer Commission methodology. The methodology is applied to a specific bio-electricity chain: the production of palm oil and a palm oil derivative, palm fatty acid distillate (PFAD), in Northeast Borneo in Malaysia, their transport to the Netherlands and co-firing with natural gas for electricity production at the Essent Claus power plant

Clay Ceramic Filter for Water Treatment

Directory of Open Access Journals (Sweden)

Zereffa Enyew Amare

2017-05-01

Full Text Available Ceramic water filters were prepared from different proportions of kaolin and soft wood and sintered at 900 °C, 950 °C, and 1000 °C. The flow rate, conductivity, pH of filtered water and removal efficiency (microbial, water hardness agent’s, nitrite and turbidity were analysed. The ceramic filter with 15 % saw dust, 80 % clay and 5 % grog that was fired at temperature of 950 °C or 1000 °C showed the best removal efficiency. Statistical ANOVA tests showed a significant difference between ceramic filters with various compositions in their removal efficiencies.

Feedlot biomass co-firing: a renewable energy alternative for coal-fired utilities. Paper no. IGEC-1-128

International Nuclear Information System (INIS)

Arumugam, S.; Thien, B.; Annamalai, K.; Sweeten, J.

2005-01-01

The swiftly growing feedlot industry in the United States upshots in the production of manure from one or more animal species in excess of what can safely be applied to farmland in accordance with nutrient management plans. Disposal of the vast quantity of manure produced as a by-product of the cattle feeding industry is one of the major operating tasks of the industry. Aside from the traditional means of disposal as fertilizer, an alternative and attractive way of overcoming this threat is to develop processes that make use of manure as an energy resource. In the present study, the feasibility of using of manure as a fuel in existing coal fired power plants is considered and appropriately termed Feedlot Biomass (FB). The technology of co-firing coal: feedlot biomass facilitates an environment friendly utilization of animal waste for the production of valuable power/steam concurrently addressing the renewable energy, groundwater contamination, and greenhouse gas concerns. Co-firing tests were performed at the Texas AandM University 30 kW t (100,000 Btu/h) laboratory-scale facility. The trials revealed the enhanced combustion of the blends. The NO emissions were less for the blend even with higher nitrogen content of FB as compared to coal. (author)

Biomass consumption and CO2, CO and main hydrocarbon gas emissions in an Amazonian forest clearing fire

Science.gov (United States)

T. G. Soares Neto; J. A. Carvalho; C. A. G. Veras; E. C. Alvarado; R. Gielow; E. N. Lincoln; T. J. Christian; R. J. Yokelson; J. C. Santos

2009-01-01

Biomass consumption and CO2, CO and hydrocarbon gas emissions in an Amazonian forest clearing fire are presented and discussed. The experiment was conducted in the arc of deforestation, near the city of Alta Floresta, state of Mato Grosso, Brazil. The average carbon content of dry biomass was 48% and the estimated average moisture content of fresh biomass was 42% on...

Life cycle assessment of coal-fired power plants and sensitivity analysis of CO2 emissions from power generation side

Science.gov (United States)

Yin, Libao; Liao, Yanfen; Zhou, Lianjie; Wang, Zhao; Ma, Xiaoqian

2017-05-01

The life cycle assessment and environmental impacts of a 1000MW coal-fired power plant were carried out in this paper. The results showed that the operation energy consumption and pollutant emission of the power plant are the highest in all sub-process, which accounts for 93.93% of the total energy consumption and 92.20% of the total emission. Compared to other pollutant emissions from the coal-fired power plant, CO2 reached up to 99.28%. Therefore, the control of CO2 emission from the coal-fired power plants was very important. Based on the BP neural network, the amount of CO2 emission from the generation side of coal-fired power plants was calculated via carbon balance method. The results showed that unit capacity, coal quality and unit operation load had great influence on the CO2 emission from coal-fired power plants in Guangdong Province. The use of high volatile and high heat value of coal also can reduce the CO2 emissions. What’s more, under higher operation load condition, the CO2 emissions of 1 kWh electric energy was less.

Physicochemical characterization of ceramics from Sao Paulo II archaeological site

International Nuclear Information System (INIS)

Ribeiro, Rogerio Baria

2013-01-01

Archaeometry is a consolidated field with a wide application of nuclear analytical techniques for the characterization, protection, and restoration of archaeological pieces. This project aimed at studying the elementary chemical composition of 70 ceramic fragments samples from Sao Paulo II archaeological site, located along the Solimoes River channel, next to Coari city, in Brazilian Amazon. The characterization of samples was performed by neutron activation analysis (NAA). By the determination of 24 elements in the ceramic fragments ( Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Sb, Sm. Rb, Se, Ta, Tb, Th, U, Yb and Zn), it was possible to define groups of samples regarding the similarity/dissimilarity in elementary chemical composition. For such a task, the multivariate statistical methods employed were cluster analysis (C A), principal component analysis (PCA) and discriminant analysis (DA). Afterwards, seven ceramic fragments were selected based on the groups previously established, for the characterization of the site temporal horizon. Those ceramic fragments were analyzed by thermoluminescence (TL) and EPR for dating purposes. The firing temperatures were determined by electron paramagnetic resonance (EPR) technique, in order to infer about some aspects of the ceramic manufacture employed by the ancient peoples that lived in Sao Paulo 11. By the results obtained in this study, it was possible to identify the quantity of clay sources employed by the ceramists and the age of the ceramic pieces. Therefore, the results of this research may contribute to the study on the occupation dynamics in the pre-colonial Brazilian Amazon. (author)

Moessbauer studies of Inca ceramics

International Nuclear Information System (INIS)

Wagner, U.; Wagner, F.E.; Marticorena, B.; Salazar, R.; Schwabe, R.; Riederer, J.

1986-01-01

To obtain information on the firing of Inca ceramics, 7 samples from different locations were studied by Moessbauer spectroscopy including a detailed laboratory refiring procedure. The glaze typical for the surface of this ware was studied by Moessbauer scattering. (Auth.)

From biomass to biocarbon : trends and tradeoffs when CO-firing

Energy Technology Data Exchange (ETDEWEB)

McLaughlin, H. [Alterna Energy Inc., Prince George, BC (Canada)

2009-07-01

This study examined current market dynamics for biomass-based fuels produced in British Columbia (BC) and consumed by utilities in Sweden. The aim of the study was to compare and develop the properties of 3 biofuels suitable for co-firing: (1) dry wood pellets; (2) torrefied wood pellets; and (3) biocarbon pellets. Biocarbon fuels are processed at higher temperatures to produce a higher energy density fuel per unit weight at a lower overall mass yield. The processing mass balances and physical properties of the pellets were investigated as well as the production and transportation costs of biofuels. Market value, profit, and maximum production costs of the pellets were examined. The study showed that the biofuel supply chain includes significant transportation costs relative to the cost of the raw biomass and biofuel conversion processes. It was concluded that higher energy density biocarbon pellets represent the most cost-effective biofuel option for co-firing with coal. 10 refs., 3 tabs., 4 figs.

From biomass to biocarbon : trends and tradeoffs when CO-firing

International Nuclear Information System (INIS)

McLaughlin, H.

2009-01-01

This study examined current market dynamics for biomass-based fuels produced in British Columbia (BC) and consumed by utilities in Sweden. The aim of the study was to compare and develop the properties of 3 biofuels suitable for co-firing: (1) dry wood pellets; (2) torrefied wood pellets; and (3) biocarbon pellets. Biocarbon fuels are processed at higher temperatures to produce a higher energy density fuel per unit weight at a lower overall mass yield. The processing mass balances and physical properties of the pellets were investigated as well as the production and transportation costs of biofuels. Market value, profit, and maximum production costs of the pellets were examined. The study showed that the biofuel supply chain includes significant transportation costs relative to the cost of the raw biomass and biofuel conversion processes. It was concluded that higher energy density biocarbon pellets represent the most cost-effective biofuel option for co-firing with coal. 10 refs., 3 tabs., 4 figs.

Research of paste transition to substrate in LTCC-technology

Science.gov (United States)

Litunov, S. N.; Yurkov, V. Y.

2018-01-01

The electronics development demands for accuracy of printed technologies, in particular, to screen printing. Under a flat blade operation the print form is deformed and the image is distorted relative to the original. A squeegee in a form of a smooth cylinder reduces distortion, but it allows obtaining satisfactory print quality only when using high density grids. The paper shows findings of using roller squeegee with dosed ink supply. The roller squeegee is provided with an elastic layer. Dosage is carried out due to the cells on the elastic layer surface. There were used meshes 100-31 and 120-34 for the stencil. The experiments were carried out with layers of photopolymers and rubber. The carried out calculations made possible to choose the optimum printing pressure. Under the selected conditions, the printed image had minimal distortion. The findings allow drawing a conclusion about the possibility of roller squeegee using in chips manufacture according to LTCC-technology.

Study and characterization of porous ceramic obtained via gelatinization

International Nuclear Information System (INIS)

Storion, A.G.; Campos, M.G.N.; Mariano, N.A.; Maestrelli, S.C.; Mariano, W.A.

2016-01-01

Conventional processes for manufacturing porous ceramic sometimes provide bodies with low mechanical strength, showing cracks and macro defects, in addition to the high complexity or cost. This work proposes a new porous ceramic processing route called cold gelatinization, using as raw material a clay with low plasticity, water and gelatin. At first, the characterization of the clay was carried out and then specimens of various compositions were produced by varying clay content (40, 50, 55 and 60% of solids) and keeping the water and gelatin content constant in the formulation. After cold forming the samples were and fired under various conditions: initial temperature of 300 or 600 °C; maximum firing temperature of 800, 900, 1000, 1100 or 1350 °C. After firing, it was obtained water absorption, apparent density, apparent porosity, linear shrinkage and mechanical resistance via 3 points bending test. The best results were for samples fired in temperatures lower than 1100 °C and 50% and 55 % of solid content. (author)

Microstructure and enhanced dielectric properties of yttrium and zirconium co-doped CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics

Energy Technology Data Exchange (ETDEWEB)

Xu, Zunping, E-mail: xzp16213@163.com [Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China); Qiang, Hua [College of Electromechanical Engineering, Chongqing College of Humanities, Science and Technology, Chongqing 401524 (China); Chen, Yi; Chen, Zhiqian [Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China)

2017-04-15

CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) ceramics doped with Y{sub 2}O{sub 3}, ZrO{sub 2}, and (Y{sub 2}O{sub 3}+ZrO{sub 2}) were prepared by the citrate-nitrate combustion derived powders in order to investigate the effect of dopants on the microstructure and electrical properties. The results showed that giant dielectric response was enhanced by co-doping of Y{sup 3+} and Zr{sup 4+} ions at the Ti site. Y{sub 2}O{sub 3} and ZrO{sub 2} additive can inhibit the grain growth. Compared with other samples, (Y{sub 2}O{sub 3}+ZrO{sub 2}) co-doped ceramics exhibit a dense and homogenous fine-grained microstructure. A much better temperature and frequency stability of dielectric properties were realized in these ceramics. The dielectric loss (tan δ) < 0.05 in the frequency range of 200 Hz–60 kHz at room temperature, and in the temperature range of 15–72 °C at 10 kHz was successfully accomplished in (Y{sub 2}O{sub 3}+ZrO{sub 2}) co-doped CCTO ceramics. Low tan δ ∼0.039 and high dielectric constant (ε{sub r} ∼10196) were observed at room temperature and 10 kHz for the above ceramic samples, and the characteristic frequency shifts to higher frequency with increasing measuring temperature. The present results indicate that (Y{sub 2}O{sub 3}+ZrO{sub 2}) co-doping may improve the dielectric properties and increase the grain boundary resistance of CCTO. - Highlights: • Y and Zr co-doped CCTO exhibits a dense and homogenous fine-grained microstructure. • Y and Zr co-doped CCTO performs a lower dielectric loss in wide-range of frequency. • Temperature and frequency stability of dielectric properties were greatly enhanced.

Early Pottery Making in Northern Coastal Peru. Part II: Field Firing Experiments

Science.gov (United States)

Shimada, I.; Goldstein, D.; Sosa, J.; Wagner, U.

2003-09-01

We present data from three seasons of experimental field work designed to recreate ancient Andean coastal ceramic firing techniques. Based on the recent discovery of two different archaeological ceramic production sites in the La Leche river valley of northern coastal Peru, the opportunity arose to apply Mössbauer spectroscopy and other analytical methods to reconstruct ancient firing procedures. Two sets of firings took place in 1993 and 1997 in Batán Grande using a partially restored Formative kiln from about 800 BC, local hardwood and cow dung as fuel. A third experiment followed in 2000 after the discovery of a Middle Sicán ceramics workshop in use between ca. AD 950 and 1050 at Huaca Sialupe, where an exact replica of an ancient kiln was built from local clay, and fired with local wood and cow dung. Additionally, inverted urns found at Huaca Sialupe were tested for their potential use as furnaces for metal working. Mössbauer spectroscopy was used to compare the physical and chemical state of specimens produced in the field experiments with ancient ceramics and with specimens produced in controlled laboratory experiments.

Influence of the co-firing on the leaching of trace pollutants from coal fly ash

Energy Technology Data Exchange (ETDEWEB)

Maria Izquierdo; Natalia Moreno; Oriol Font; Xavier Querol; Esther Alvarez; Diano Antenucci; Henk Nugteren; Yolanda Luna; Constantino Fernandez-Pereira [Institute of Earth Sciences ' Jaume Almera' (CSIC), Barcelona (Spain)

2008-08-15

The (co)-firing of low-cost alternative fuels is expected to increase in the forthcoming years in the EU because of the economic and environmental benefits provided by this technology. This study deals with the impact of the different coal/waste fuel ratio of the feed blend on the mineralogy, the chemical composition and especially on the leaching properties of fly ash. Different blends of coal, petroleum coke, sewage sludge, wood pellets, coal tailings and other minor biomass fuels were tested in PCC (pulverised coal combustion) and FBC (fluidized bed combustion) power plants. The co-firing of the studied blends did not drastically modify the mineralogy, bulk composition or the overall leaching of the fly ash obtained. This suggests that the co-firing process using the alternative fuels studied does not entail significant limitations in the re-use or management strategies of fly ash. 34 refs., 4 figs., 3 tabs.

Study of Wettability of Clayey Ceramic and Fluorescent Lamp Glass Waste Powders

Science.gov (United States)

Morais, Alline Sardinha Cordeiro; Monteiro, Sergio Neves; Ribeiro, Sebastião; Sardinha, Leonardo Carneiro; Vieira, Carlos Maurício Fontes

The glass tube of spent fluorescent lamps is contaminated with mercury, which might be a serious hazard in the case of conventional recycling by melting with other glasses. A possible solution could be its incorporation into a clay body to fabricate common fired ceramics such as bricks and tiles. The objective of this work is to characterize a type of fluorescent lamp glass waste to be incorporated into a clayey ceramic. The characterization was performed in terms of wettability tests to evaluate the interaction between the surface of the clayey ceramic and glass waste as a function of the firing temperature. The results showed that the contact angle decreased with increasing temperature, reaching a value of 79°, at a temperature of 1100°C, but not sufficient to completely wet the ceramic. However, compatible chemical composition and reduction of porosity by the flow of soft glass waste between the clay particles favor the consolidation of the ceramics structure above 900°C.

A review on waste heat recovery from exhaust in the ceramics industry

Science.gov (United States)

Delpech, Bertrand; Axcell, Brian; Jouhara, Hussam

2017-11-01

Following the energy crisis in 1980, many saving technologies have been investigated with attempts to implement them into various industries, one of them is the field of ceramic production. In order to comply with energy saving trends and environmental issues, the European ceramic industry sector has developed energy efficient systems which reduced significantly production time and costs and reduced total energy consumption. The last achievement is of great importance as the energy consumption of the ceramic process accounts for a significant percentage of the total production costs. More precisely, the firing stage consumes the highest amount of energy during the whole ceramic production process. The use of roller kilns, fired by natural gas, involves a loss of 50% of the input energy via the flue gas and the cooling gas exhausts. This review paper briefly describes the production process of the different ceramic products, with a focus on the ceramic sector in Europe. Due to the limited on waste heat recovery in the ceramic industry, other high temperature waste heat recovery applications are considered in the paper, such as in concrete and steel production, which could have a potential use in the ceramic industry. The state of the art technologies used in the ceramics industry are reviewed with a special interest in waste heat recovery from the ceramic process exhaust stacks and energy saving technologies.

Enhanced green upconversion by controlled ceramization of Er{sup 3+}–Yb{sup 3+} co-doped sodium niobium tellurite glass–ceramics for low temperature sensors

Energy Technology Data Exchange (ETDEWEB)

Suresh Kumar, J., E-mail: suresh@ua.pt; Pavani, K.; Graça, M.P.F.; Soares, M.J.

2014-12-25

Highlights: • Upconversion luminescence improved in glass–ceramics compared to host glass. • Judd–Ofelt and radiative parameters calculated. • NIR decay curve results concur the results of improved luminescence. • Temperature dependent upconversion support the use of materials for sensors. - Abstract: Tellurite based glasses are well-known for their upconversion properties besides having a disadvantage of low mechanical strength dragging them away from practical applications. The present work deals with preparation of sodium niobium tellurite (SNT) glasses using melt quenching method, in which small quantities of boron and silicon in the form of oxides are added to improve their mechanical properties. Controlled heat treatment is performed to ceramize the prepared glasses based on the thermal data given by DTA. XRD and SEM profiles of the glass–ceramics which confirmed the formation of crystalline monoclinic Sodium Tellurium Niobium Oxide (Na{sub 1.4}Nb{sub 3}Te{sub 4.9}O{sub 18}) phase (JCPDS card No. 04–011-7556). Upconversion measurements in the visible region were made for the prepared Er{sup 3+}–Yb{sup 3+} co-doped glasses and glass–ceramics with 980 nm laser excitation varying the laser power and concentration of Er{sup 3+} ions. Results showed that the upconversion luminescence intensity was enhanced by ten times in SNT glass–ceramics compared to that in the SNT glasses. Decay curves give evidence of high performance of glass–ceramics compared to glasses due to ceramization and structural changes. Temperature dependent visible upconversion was performed to test the ability of efficient SNT glass–ceramic at low temperatures and variation of upconversion intensities was studied.

Forest fires in Mediterranean countries: CO2 emissions and mitigation possibilities through prescribed burning

OpenAIRE

Fernandes, Paulo; Terhi, Vilén

2011-01-01

Forest fires are integral to the Mediterranean Basin but fire incidence has increased dramatically during the past decades and fire is expected to become more prevalent in the future due to climate change. Fuel modification by prescribed burning reduces the spread and intensity potential of subsequent wildfires. We used the most recent published data to calculate the average annual wildfire CO2 emissions in France, Greece, Italy, Portugal and Spain following the IPCC guidelines. The effect of...

Incorporation of petroleum coke into red ceramic; Incorporacao de coque de petroleo em ceramica vermelha

Energy Technology Data Exchange (ETDEWEB)

Freitas, L.A. de; Monteiro, S.N.; Sanchez, R.; Vieira, C.M.F. [Laboratorio de Materiais Avancados - LAMAV, Universidade Estadual do Norte Fluminense Darcy Ribeiro - UENF, Campos dos Goytacazes, RJ (Brazil)], e-mails: sanchez@uenf.br, vieira@uenf.br

2011-04-15

This work has as its objective the evaluation of the effect of incorporation of petroleum coke in the physical and mechanical properties of red ceramic. Compositions were prepared with 0%, 1%, 2% and 4 wt.% of petroleum coke incorporated into a kaolinitic clayey body. Rectangular specimens were formed by extrusion to fire at 850 deg C and 1050 deg C. The determined physical and mechanical properties were flexural rupture strength and water absorption. The microstructure of the fired ceramics was evaluated by optical microscopy. The results show that the petroleum coke waste can significantly contribute to reduce the energy consumption during the firing stage. However, incorporations must be done in amounts around 1 wt.% to avoid deleterious effect on the water absorption of the ceramic. (author)

Manufacture of a ceramic paper for art applications

Science.gov (United States)

Dölle, K.; Honig, A.; Piatkowski, J.; Kuempel, C.

2018-01-01

Ceramic paper products are mostly used as high temperature ceramic insulation products. They offer an effective solution for most demanding heat management and insulation applications. The objective for this research project was to create a ceramic paper like product that combines the advantages of paper fibers, ceramic filler, and a clay product into one product, which can be produced on a continuous base with a paper machine. The produced ceramic paper product had a ceramic filler level between 59.68% and 78.8% with a basis weight between 322.9 g/m² and 693.7 g/m², and a final moisture content of 58.6% to 44.7% respectively. The wooden fiber served as a support medium for the ceramic filler material during production on the paper machine and during the conversion process into art pieces. During firing in a kiln, the fiber material combusted and the ceramic filler material mixture acts as common pottery clay, holding the desired shape of the art pieces produced.

The chemical composition and compression strengths of refractory ceramics, tested for 3 curing temperatures

International Nuclear Information System (INIS)

Wan Khairuddin bin Wan Ali

1994-01-01

An investigation was carried out to determine and compile the mechanical strength of a refractory ceramic made of ground fire bricks and refractory fire mortar. Three different compositions were studied for the compression strength and it was found that the composition with 50% fire bricks and 50% fire mortar gives the best mechanical strength. With this composition the maximum failure compression stress is 3.2 MPa. and the Young Modulus is 403.5 MPa. The investigation also shows that the curing temperatures and the composition percentages play an important role in determining the strength of the ceramic. The trend obtained from the investigation shows that there is the possibility that an optimum value of composition percentage exist

Potential high temperature corrosion problems due to co-firing of biomass and fossil fuels

DEFF Research Database (Denmark)

Montgomery, Melanie; Vilhelmsen, T.; Jensen, S.A.

2007-01-01

Over the past years, considerable high temperature corrosion problems have been encountered when firing biomass in power plants due to the high content of potassium chloride in the deposits. Therefore to combat chloride corrosion problems co-firing of biomass with a fossil fuel has been undertaken....... This results in potassium chloride being converted to potassium sulphate in the combustion chamber and it is sulphate rich deposits that are deposited on the vulnerable metallic surfaces such as high temperature superheaters. Although this removes the problem of chloride corrosion, other corrosion mechanisms...... appear such as sulphidation and hot corrosion due to sulphate deposits. At Studstrup power plant Unit 4, based on trials with exposure times of 3000 hours using 0-20% straw co-firing with coal, the plant now runs with a fuel of 10% straw + coal. After three years exposure in this environment...

Highly porous polymer-derived wollastonite-hydroxycarbonate apatite ceramics for bone regeneration.

Science.gov (United States)

Fiocco, L; Li, S; Bernardo, E; Stevens, M M; Jones, J R

2016-04-12

A novel strategy was employed to synthesize highly porous wollastonite-hydroxycarbonate apatite ceramic scaffolds for bone regeneration. A commercial liquid preceramic polymer filled with micro-CaCO3 powders was foamed at low temperature (at 350 °C), using the decomposition of a hydrazine additive, and then converted into ceramic by a treatment at 700 °C. Hydroxycarbonate apatite was later developed by a phosphatization treatment of ceramized foams, in a P-rich solution, while wollastonite was obtained by a second firing, at 900 °C. The effectiveness of the method was proven by x-ray diffraction analysis, showing the presence of the two expected crystalline phases. Porosity, interconnect size distribution and mechanical strength were in the range that is thought to be suitable for bone regeneration in non-load bearing sites (compressive strength ≈ 3 MPa, porosity ≈ 90%, modal interconnect diameter ≈ 130-160 μm). In addition, bioactivity and ion release rate were assessed in simulated body fluid (SBF). MC3T3 osteoblast precursor cells were able to colonize the material in vitro through the pore architecture and expressed osteogenic markers.

Does the CO2 laser reduce bond strength in different types of ceramic brackets?

Directory of Open Access Journals (Sweden)

Fábio Lourenço Romano

Full Text Available ABSTRACT OBJECTIVE: The aim of this study was to assess in vitro the influence of the CO2 laser and of the type of ceramic bracket on the shear bond strength (SBS to enamel. METHODS: A total of 60 enamel test surfaces were obtained from bovine incisors and randomly assigned to two groups, according to the ceramic bracket used: Allure (A; Transcend (T. Each group was divided into 2 subgroups (n = 15: L, laser (10W, 3s; C, no laser, or control. Twenty-four hours after the bonding protocol using Transbond XT, SBS was tested at a crosshead speed of 0.5 mm/min in a universal testing machine. After debonding, the Adhesive Remnant Index (ARI was evaluated at 10 x magnification and compared among the groups. Data were analyzed by one-way ANOVA, Tukey’s, Mann-Whitney’s and Kruskal-Wallis tests (α = 0.05. RESULTS: Mean SBS in MPa were: AL = 0.88 ± 0.84; AC = 12.22 ± 3.45; TL = 12.10 ± 5.11; TC = 17.71 ± 6.16. ARI analysis showed that 73% of the specimens presented the entire adhesive remaining on the tooth surfaces (score 3. TC group presented significantly higher SBS than the other groups. The lased specimens showed significantly lower bond strength than the non-lased groups for both tested brackets. CONCLUSION: CO2 laser irradiation decreased SBS values of the polycrystalline ceramic brackets, mainly Allure.

X-Ray diffraction and scanning electron microscopy-energy dispersive spectroscopic analysis of ceramõmetal interface at different firing temperatures

Directory of Open Access Journals (Sweden)

Monika Saini

2010-01-01

Full Text Available Objective: Porcelain chipping from porcelain fused to metal restoration has been Achilles heel till date. There has been advent of newer ceramics in past but but none of them has been a panacea for Porcelain fracture. An optimal firing is thus essential for the clinical success of the porcelain-fused to metal restoration. The aim of the present study was to evaluate ceramo-metal interface at different firing temperature using XRD and SEM-EDS analysis. Clinical implication of the study was to predict the optimal firing temperature at which porcelain should be fused with metal in order to possibly prevent the occasional failure of the porcelain fused to metal restorations. Materials and Methods: To meet the above-mentioned goal, porcelain was fused to metal at different firing temperatures (930-990°C in vacuum. The microstructural observations of interface between porcelain and metal were evaluated using X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. Results: Based on the experimental investigation of the interaction zone of porcelain fused to metal samples, it was observed that as the firing temperature was increased, the pores became less in number as well as the size of the pores decreased at the porcelain/metal interface upto 975°C but increased in size at 990°C. The least number of pores with least diameter were found in samples fired at 975°C. Several oxides like Cr 2 O 3 , NiO, and Al 2 O 3 and intermetallic compounds (CrSi 2 , AlNi 3 were also formed in the interaction zone. Conclusions : It is suggested that the presence of pores may trigger the crack propagation along the interface, causing the failure of the porcelain fused to metal restoration during masticatory action.

Corrosion behaviour and surface analysis of a Co-Cr and two Ni-Cr dental alloys before and after simulated porcelain firing.

Science.gov (United States)

Qiu, Jing; Yu, Wei-Qiang; Zhang, Fu-Qiang; Smales, Roger J; Zhang, Yi-Lin; Lu, Chun-Hui

2011-02-01

This study evaluated the corrosion behaviour and surface properties of a commercial cobalt-chromium (Co-Cr) alloy and two nickel-chromium (Ni-Cr) alloys [beryllium (Be)-free and Be-containing] before and after a simulated porcelain-firing process. Before porcelain firing, the microstructure, surface composition and hardness, electrochemical corrosion properties, and metal-ion release of as-cast alloy specimens were examined. After firing, similar alloy specimens were examined for the same properties. In both as-cast and fired conditions, the Co-Cr alloy (Wirobond C) showed significantly more resistance to corrosion than the two Ni-Cr alloys. After firing, the corrosion rate of the Be-free Ni-Cr alloy (Stellite N9) increased significantly, which corresponded to a reduction in the levels of Cr, molybdenum (Mo), and Ni in the surface oxides and to a reduction in the thickness of the surface oxide film. The corrosion properties of the Co-Cr alloy and the Be-containing Ni-Cr alloy (ChangPing) were not significantly affected by the firing process. Porcelain firing also changed the microstructure and microhardness values of the alloys, and there were increases in the release of Co and Ni ions, especially for Ni from the Be-free Ni-Cr alloy. Thus, the corrosion rate of the Be-free Ni-Cr alloy increased significantly after porcelain firing, whereas the firing process had little effect on the corrosion susceptibility of the Co-Cr alloy and the Be-containing Ni-Cr alloy. © 2011 Eur J Oral Sci.

An Integrable SIW Phase Shifter in a Partially Magnetized Ferrite LTCC Package

KAUST Repository

Nafe, Ahmed

2015-06-09

There is a growing need for small size integrable phased antenna arrays for emerging satellite communications on-the-move applications. Traditional ferrite-based phase shifters are generally bulky due to the need of electromagnets for biasing, yielding them unsuitable for this kind of application. In this paper, a novel compact light-weight substrate integrated waveguide (SIW) based phase shifter realized in a multi-layer ferrite low-temperature co-fired ceramic package with embedded bias windings is reported. By using embedded windings and operating the material in a partially magnetized state, the required bias magnetic field could be significantly reduced from typically about 1000 Oe to less than 50 Oe. Moreover, the presented phase shifter has two modes of operations corresponding to two different biasing scenarios of the SIW, namely, symmetric and anti-symmetric bias. Under anti-symmetric bias, the phase shifter can achieve high nonreciprocal phase shift, whereas under symmetric bias, the phase shift is reciprocal, but the available phase shift is less than the anti-symmetric case. The fabricated prototype operates in the 11.5-13.5-GHz range and has a peak figure of merit (phase shift per decibel of loss) of 102°/dB and a maximum phase shift per unit length of 153°/cm, which are more than five times the previously reported figures for this technology. Due to the use of embedded windings, the presented phase shifter offers a huge size reduction from the order of cm3 to mm3, making it particularly useful for mobile phased-array applications. © 2015 IEEE.

Effect of Mg and Si co-substitution on microstructure and strength of tricalcium phosphate ceramics.

Science.gov (United States)

García-Páez, Ismael H; Carrodeguas, Raúl García; De Aza, Antonio H; Baudín, Carmen; Pena, Pilar

2014-02-01

Magnesium and silicon co-doped tricalcium phosphate (TCP) ceramics with compositions corresponding to 0, 5 and 10wt% CaMg(SiO3)2 in the system Ca3(PO4)2-CaMg(SiO3)2 were obtained by conventional sintering of compacted mixtures of Ca3(PO4)2, MgO, SiO2 and CaCO3 powders at temperatures between 1100 and 1450°C. Microstructural analyses were performed by X-ray diffraction and field emission scanning electron microscopy with energy dispersive spectroscopy. Major phases in the obtained ceramics were β- or α+β-tricalcium phosphate containing Mg and Si in solid solution. Certain amounts of liquid were formed during sintering depending on composition and temperature. There were found significant differences in distributions of strength determined by the diametral compression of disc tests (DCDT). Failure strengths were controlled by microstructural defects associated with phase development. Mg and Si additions were found to be effective to improve densification and associated strength of TCP bioceramics due to the enhancement of sintering by the low viscosity liquids formed. The highest density and strength were obtained for the TCP ceramic containing 5wt% CaMg(SiO3)2 sintered at 1300°C. Cracking and porosity increased at higher temperatures due to grain growth and swelling. © 2013 Published by Elsevier Ltd.

Mitigating operating room fires: development of a carbon dioxide fire prevention device.

Science.gov (United States)

Culp, William C; Kimbrough, Bradly A; Luna, Sarah; Maguddayao, Aris J

2014-04-01

Operating room fires are sentinel events that present a real danger to surgical patients and occur at least as frequently as wrong-sided surgery. For fire to occur, the 3 points of the fire triad must be present: an oxidizer, an ignition source, and fuel source. The electrosurgical unit (ESU) pencil triggers most operating room fires. Carbon dioxide (CO2) is a gas that prevents ignition and suppresses fire by displacing oxygen. We hypothesize that a device can be created to reduce operating room fires by generating a cone of CO2 around the ESU pencil tip. One such device was created by fabricating a divergent nozzle and connecting it to a CO2 source. This device was then placed over the ESU pencil, allowing the tip to be encased in a cone of CO2 gas. The device was then tested in 21%, 50%, and 100% oxygen environments. The ESU was activated at 50 W cut mode while placing the ESU pencil tip on a laparotomy sponge resting on an aluminum test plate for up to 30 seconds or until the sponge ignited. High-speed videography was used to identify time of ignition. Each test was performed in each oxygen environment 5 times with the device activated (CO2 flow 8 L/min) and with the device deactivated (no CO2 flow-control). In addition, 3-dimensional spatial mapping of CO2 concentrations was performed with a CO2 sampling device. The median ± SD [range] ignition time of the control group in 21% oxygen was 2.9 s ± 0.44 [2.3-3.0], in 50% oxygen 0.58 s ± 0.12 [0.47-0.73], and in 100% oxygen 0.48 s ± 0.50 [0.03-1.27]. Fires were ignited with each control trial (15/15); no fires ignited when the device was used (0/15, P fire prevention device can be created by using a divergent nozzle design through which CO2 passes, creating a cone of fire suppressant. This device as demonstrated in a flammability model effectively reduced the risk of fire. CO2 3-dimensional spatial mapping suggests effective fire reduction at least 1 cm away from the tip of the ESU pencil at 8 L/min CO2 flow

Characterization of Al{sub 2}O{sub 3}-Co ceramic composite obtained by high energy mill; Caracterizacao de composito ceramico Al{sub 2}O{sub 3}-CO obtido por moagem de alta energia (MAE)

Energy Technology Data Exchange (ETDEWEB)

Souza, J.L.; Assis, R.B. de; Carlos, E.M.; Oliveira, T.P.; Costa, F.A. da, E-mail: leonaldojs@hotmail.com [Universidade Federal do Rio Grande do Norte (PPGCEM/UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica

2014-07-01

This work aims to characterize the ceramic composite Al{sub 2}O3-Co obtained by high energy grinding. The composites were obtained by milling Al{sub 2}O{sub 3} and Co in a high energy mill at a speed of 400 rpm, in proportions of 5 to 20% Cobalt (Co). Ceramic composites with 5 and 20% cobalt were sintered at 1200 and 1300 ° C, with a 60-minute plateau and a heating rate of 10 ° C / min. The samples were characterized by X-ray diffraction (XRD), thermogravimetry and differential scanning calorimetry (TG / DSC) and scanning electron microscopy (SEM). The results show the significant effect of cobalt percentage and high energy grinding on the final properties of the Al{sub 2}O{sub 3} - Co ceramic composite, presenting satisfactory values for the composite with a 20% cobalt percentage, showing to be a promising material for application in cutting tools.

Method of producing monolithic ceramic cross-flow filter

Science.gov (United States)

Larsen, David A.; Bacchi, David P.; Connors, Timothy F.; Collins, III, Edwin L.

1998-01-01

Ceramic filter of various configuration have been used to filter particulates from hot gases exhausted from coal-fired systems. Prior ceramic cross-flow filters have been favored over other types, but those previously horn have been assemblies of parts somehow fastened together and consequently subject often to distortion or delamination on exposure hot gas in normal use. The present new monolithic, seamless, cross-flow ceramic filters, being of one-piece construction, are not prone to such failure. Further, these new products are made by novel casting process which involves the key steps of demolding the ceramic filter green body so that none of the fragile inner walls of the filter is cracked or broken.

Additive Manufacturing for Cost Efficient Production of Compact Ceramic Heat Exchangers and Recuperators

Energy Technology Data Exchange (ETDEWEB)

Shulman, Holly [Ceralink Incorporated, Troy, NY (United States); Ross, Nicole [Ceralink Incorporated, Troy, NY (United States)

2015-10-30

An additive manufacture technique known as laminated object manufacturing (LOM) was used to fabricate compact ceramic heat exchanger prototypes. LOM uses precision CO2 laser cutting of ceramic green tapes, which are then precision stacked to build a 3D object with fine internal features. Modeling was used to develop prototype designs and predict the thermal response, stress, and efficiency in the ceramic heat exchangers. Build testing and materials analyses were used to provide feedback for the design selection. During this development process, laminated object manufacturing protocols were established. This included laser optimization, strategies for fine feature integrity, lamination fluid control, green handling, and firing profile. Three full size prototypes were fabricated using two different designs. One prototype was selected for performance testing. During testing, cross talk leakage prevented the application of a high pressure differential, however, the prototype was successful at withstanding the high temperature operating conditions (1300 °F). In addition, analysis showed that the bulk of the part did not have cracks or leakage issues. This led to the development of a module method for next generation LOM heat exchangers. A scale-up cost analysis showed that given a purpose built LOM system, these ceramic heat exchangers would be affordable for the applications.

Magnetic Diagnosis Upgrade and Analysis for MHD Instabilities on the J-TEXT

Science.gov (United States)

Guo, Daojing; Hu, Qiming; Zhuang, Ge; Wang, Nengchao; Ding, Yonghua; Tang, Yuejin; Yu, Qingquan; Huazhong University of Science; Technology Team; Max-Planck-Institut für Plasmaphysik Collaboration

2017-10-01

The magnetic diagnostic system on the J-TEXT tokamak has been upgraded to measure the magnetohydrodynamic (MHD) instabilities with diverse bands of frequencies. 12 saddle loop probes and 73 Mirnov probes are newly developed. The fabrication and installment of the new probes are elaborately designed, in consideration of higher spatial resolution and better amplitude-frequency characteristic. In this case, the probes utilize two kinds of novel fabrication craft, one of which is low temperature co-fired ceramics (LTCC), the other is flexible printed circuit (FPC). A great deal of experiments on the J-TEXT have validated the stability of the new system. Some typical discharges observed by the new diagnostic system are reviewed. In order to extract useful information from raw signals, several efficient signal processing methods are reviewed. An analytical model based on lumped eddy current circuits is used to compensate equilibrium flux and the corresponding eddy current fluxes, a visualization processing based on singular value decomposition (SVD) and cross-power spectrum are applied to detect the mode number. Fusion Science Program of China (Contract Nos. 2015GB111001 and 2014GB108000) and the National Natural Science Foundation of China (Contract Nos. 11505069 and 11405068).

Scanning electron microscopical observation of an osteoblast/osteoclast co-culture on micropatterned orthopaedic ceramics.

Science.gov (United States)

Halai, Mansur; Ker, Andrew; Meek, Rm Dominic; Nadeem, Danish; Sjostrom, Terje; Su, Bo; McNamara, Laura E; Dalby, Matthew J; Young, Peter S

2014-01-01

In biomaterial engineering, the surface of an implant can influence cell differentiation, adhesion and affinity towards the implant. On contact with an implant, bone marrow-derived mesenchymal stromal cells demonstrate differentiation towards bone forming osteoblasts, which can improve osteointegration. The process of micropatterning has been shown to improve osteointegration in polymers, but there are few reports surrounding ceramics. The purpose of this study was to establish a co-culture of bone marrow-derived mesenchymal stromal cells with osteoclast progenitor cells and to observe the response to micropatterned zirconia toughened alumina ceramics with 30 µm diameter pits. The aim was to establish whether the pits were specifically bioactive towards osteogenesis or were generally bioactive and would also stimulate osteoclastogenesis that could potentially lead to osteolysis. We demonstrate specific bioactivity of micropatterns towards osteogenesis, with more nodule formation and less osteoclastogenesis compared to planar controls. In addition, we found that that macrophage and osteoclast-like cells did not interact with the pits and formed fewer full-size osteoclast-like cells on the pitted surfaces. This may have a role when designing ceramic orthopaedic implants.

Use of ash from the incineration of firewood and sawdust into clayey ceramic

International Nuclear Information System (INIS)

Rossi, D.P.; Monteiro, S.N.; Vieira, C.M.F.

2011-01-01

This work has as its objective to evaluate the effect of the incorporation of a type of waste, ash obtained from burning eucalyptus firewood and sawdust, in the physical and mechanical properties of red ceramic. The waste was characterized by DTA/TG and XRF. Formulations were prepared with incorporation of the waste in amounts up to 10 wt.%, into a kaolinitic clayey body. Rectangular specimens were prepared by uniaxial mold-press at 20 MPa and then fired at 650 and 950 deg C. The evaluated physical and mechanical properties were: linear shrinkage, water absorption and flexural rupture strength. The microstructure of the fired ceramics was evaluated by optical microscopy. The results showed that the ash has an high amount of weight loss during the firing, being predominantly composed of quartz and calcium compounds. The incorporation of the ash increased the water absorption and abruptly decreased the mechanical strength of the ceramic at the investigated temperatures for all amount of incorporated ash. (author)

Characterization of some archaeological ceramics and clay samples from Zamala - Far-northern part of Cameroon (West Central Africa)

Energy Technology Data Exchange (ETDEWEB)

Ntah, Z.L. Epossi; Sobott, R.; Bente, K., E-mail: zoilaepossi@yahoo.fr [Institute of Mineralogy, Crystallography and Materials Science, University of Leipzig (Germany); Fabbri, B. [Institute of Science and Technology for Ceramics, National Research Council (CNR) of Italy, Faenza (Italy)

2017-07-15

Seventeen ceramics samples (515±95 BP, about 580 years old) and two clay raw materials from Zamala (Far-northern, Cameroon) were characterized by X-ray diffraction (XRD), thermal analysis (DTA/TG) and X-ray fluorescence spectroscopy. The aim of the work was the deduction of the production technology and provenance of these ceramics. With the exception of one sample the analysed ceramics formed a homogeneous chemical and mineralogical group. The observed mineralogical phases were quartz, mica (biotite), potassium feldspar (microcline) and plagioclase (albite and oligoclase). The XRD study of two local clays yielded the presence of quartz, kaolinite, mica, feldspar and plagioclase. The presence of the broad endothermic peak in the DTA/TG curves of the clays and its absence in the curves of the ceramics indicated that the firing temperature of the ceramics was above 550-600 °C, which is the temperature of the kaolinite-metakaolinite transformation. The firing experiments of the clay between 400-1200 °C in oxidizing atmosphere showed that mica disappeared above 900 °C. Therefore, the firing temperature of the sherds should have been between 600-900 °C. The chemical correlation between ceramics and local clay materials pointed out to a local production of these ceramics. (author)

Investigation of the setting reaction in magnesium phosphate ceramics with quasielastic neutron scattering

Czech Academy of Sciences Publication Activity Database

Viani, Alberto; Zbiri, M.; Bordallo, H. N.; Gualtieri, A. F.; Mácová, Petra

2017-01-01

Roč. 121, č. 21 (2017), s. 11355-11367 ISSN 1932-7447 R&D Projects: GA MŠk(CZ) LO1219 Keywords : magnesium potassium phosphate ceramics * amorphous materials * NMR-spectroscopy Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 4.536, year: 2016 http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.7b01396

Moessbauer analysis of recent ceramic finds from Chavin

International Nuclear Information System (INIS)

Wagner, U.; Wagner, F.E.; Stockklauser, A.; Salazar, R.; Riederer, J.; Kauffmann-Doig, F.

1986-01-01

A large number of ceramic sherds from Chavin, Peru, as well as recent clay samples from the same region have been studied by Moessbauer spectroscopy. The changes of the Moessbauer spectra of the clay were studied as a function of firing temperature and atmosphere. From a comparison of these data with those from the sherds one can make estimates of the precolumbian firing conditions. (Auth.)

Increased electricity production from straw by co-firing with woody biomass; Oekad elproduktion med halm genom sameldning med traedbraenslen

Energy Technology Data Exchange (ETDEWEB)

Hedman, Henry; Nordgren, Daniel; Bostroem, Dan; Oehman, Marcus; Padban, Nader

2011-01-15

The use of straw in pulverised fuel-fired boiler is great technical challenge, especially when it comes to dealing with problems from slagging and fouling. Introduction of straw in the fuel mix of Swedish boilers will most likely be done by co-firing of woody biomass with straw, and this can provide a means to reduce the (well-documented) problems with fouling and slagging from straw. The project will focus on the faith of alkali metals (K and Na) as well as studies on the slagging and fouling propensity in pulverised fuel-fired boilers when straw is co-fired with woody biomass. A total of 5 different fuel mixtures has been fired in a 150 kW pilot-scale pulverised fuel-fired burner: (i) straw 100 %, (ii) straw/bark 50/50 %, (iii) straw/bark 75/25 % (iv) straw/wood 75/25 % (v) straw/wood 50/50 % (wt-%). The adding of woody biomass to straw has in all of the above-mentioned cases had some positive effect. In general, in all of the ash deposits, an increase in the concentration of Calcium (Ca) has been observed as well as a decrease in the concentrations of Potassium (K) and Silicon (Si). These general trends should be considered as a positive when combustion of straw is considered. Out of all ash deposits collected in the furnace, the characteristics of the bottom ash displayed the largest (positive) change and visual inspections and chemical analysis of the bottom ash showed that the ash had become more porous and contained more Calcium as more woody biomass was introduced in the fuel mix. The deposit build-up rate on the air cooled probes was reduced when more woody biomass was co-fired with straw. The reduction was highest in the trial where 50% woody biomass was used and the most apparent changes in composition could be seen in Calcium (increase) and Potassium (decrease). Danish experiences from introducing straw in pulverised fuel-fired boiler indicate that extra soot-blowers should be considered at the furnace walls and in connection to screen-tubes (if any

Resource potential for renewable energy generation from co-firing of woody biomass with coal in the Northern U.S.

Science.gov (United States)

Michael E. Goerndt; Francisco X. Aguilar; Kenneth Skog

2013-01-01

Past studies have established measures of co-firing potential at varying spatial scales to assess opportunities for renewable energy generation from woody biomass. This study estimated physical availability, within ecological and public policy constraints, and associated harvesting and delivery costs of woody biomass for co-firing in selected power plants of the...

JV Task 106 - Feasibility of CO2 Capture Technologies for Existing North Dakota Lignite-Fired Pulverized Coal Boilers

Energy Technology Data Exchange (ETDEWEB)

Michael L. Jones; Brandon M. Pavlish; Melanie D. Jensen

2007-05-01

The goal of this project is to provide a technical review and evaluation of various carbon dioxide (CO{sub 2}) capture technologies, with a focus on the applicability to lignite-fired facilities within North Dakota. The motivation for the project came from the Lignite Energy Council's (LEC's) need to identify the feasibility of CO{sub 2} capture technologies for existing North Dakota lignite-fired, pulverized coal (pc) power plants. A literature review was completed to determine the commercially available technologies as well as to identify emerging CO{sub 2} capture technologies that are currently in the research or demonstration phase. The literature review revealed few commercially available technologies for a coal-fired power plant. CO{sub 2} separation and capture using amine scrubbing have been performed for several years in industry and could be applied to an existing pc-fired power plant. Other promising technologies do exist, but many are still in the research and demonstration phases. Oxyfuel combustion, a technology that has been used in industry for several years to increase boiler efficiency, is in the process of being tailored for CO{sub 2} separation and capture. These two technologies were chosen for evaluation for CO{sub 2} separation and capture from coal-fired power plants. Although oxyfuel combustion is still in the pilot-scale demonstration phase, it was chosen to be evaluated at LEC's request because it is one of the most promising emerging technologies. As part of the evaluation of the two chosen technologies, a conceptual design, a mass and energy balance, and an economic evaluation were completed.

Health and environmental effects of refuse derived fuel (RDF) production and RDF/coal co-firing technologies

Energy Technology Data Exchange (ETDEWEB)

O' Toole, J.J.; Wessels, T.E.; Lynch, J.F.; Fassel, V.A.; Lembke, L.L.; Kniseley, R.N.; Norton, G.A.; Junk, G.A.; Richard, J.J.; Dekalb, E.L.; Dobosy, R.J.

1981-10-01

Six facilities, representing the scope of different co-firing techniques with their associated RDF production systems were reviewed in detail for combustion equipment, firing modes, emission control systems, residue handling/disposal, and effluent wastewater treatment. These facilities encompass all currently operational or soon to be operational co-firing plants and associated RDF production systems. Occupational health and safety risks for these plants were evaluated on the basis of fatal and nonfatal accidents and disease arising from the respective fuel cycles, coal and RDF. Occupational risks include exposure to pathogenic organisms in the workplace. Unusual events that are life threatening in the RDF processing industry (e.g., explosions) are also discussed and remedial and safety measures reviewed. 80 refs., 4 figs., 30 tabs.

CONCEPTUAL DESIGN ASSESSMENT FOR THE CO-FIRING OF BIO-REFINERY SUPPLIED LIGNIN PROJECT

International Nuclear Information System (INIS)

Ted Berglund; Jeffrey T. Ranney; Carol L. Babb; Jacqueline G. Broder

2001-01-01

The major aspects of this project are proceeding toward completion. Prior to this quarter, design criteria, tentative site selection, facility layout, and preliminary facility cost estimates have been completed and issued for review. Processing of bio-solids was completed, providing material for the pilot operations. Pilot facility design, equipment selection, and modification were completed during the fourth quarter of 2000. Initial pilot facility shakedown was completed during the fourth quarter. After some unavoidable delays, a suitable representative supply of municipal solid waste (MSW) feed material was procured. During this quarter (first quarter of 2001), shredding of the feed material was completed and final feed conditioning was completed. Pilot facility hydrolysis production was completed to produce lignin for co-fire testing. Pilot facility modifications continued to improve facility operations and performance during the first quarter of 2001. Samples of the co-fire fuel material were sent to the co-fire facility for evaluation. The TVA-Colbert facility has neared completion of the task to evaluate the co-location of the Masada facility on the operation of the power generation facility. The TVA-Colbert fossil plant is fully capable of providing a reliable steam supply. The preferred steam supply connection points and steam pipeline routing have been identified. The environmental review of the pipeline routing has been completed and no major impacts have been identified. Detailed assessment of steam export impacts on the Colbert boiler system have been completed and a cost estimate for steam supply system is being developed

Theory and design of a half-mode SIW Ferrite LTCC phase shifter

KAUST Repository

Ghaffar, Farhan A.

2015-05-01

A half mode SIW based Ferrite LTCC phase shifter is presented in this work. A theoretical model to predict the phase shift in the partially magnetized state has been derived. Contrary to the bulky external magnets employed by conventional ferrite phase shifters for biasing, this design uses bias windings embedded within the ferrite substrate. This not only enables miniaturization but also reduces the required bias fields considerably by avoiding the demagnetization effect (fields lost at air-dielectric interface for external biasing schemes). The design is optimized with the aid of magnetostatic and microwave simulations which are later verified through measurements of a prototype. The fabricated phase shifter provides a differential phase shift of 110°/cm and an FoM of 55°/dB for an applied DC current of 240 mA.

Transient Heating and Thermomechanical Stress Modeling of Ceramic HEPA Filters

Energy Technology Data Exchange (ETDEWEB)

Bogle, Brandon [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kelly, James [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Haslam, Jeffrey [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-09-29

The purpose of this report is to showcase an initial finite-element analysis model of a ceramic High-Efficiency Particulate (HEPA) Air filter design. Next generation HEPA filter assemblies are being developed at LLNL to withstand high-temperature fire scenarios by use of ceramics and advanced materials. The filters are meant for use in radiological and nuclear facilities, and are required to survive 500°C fires over an hour duration. During such conditions, however, collecting data under varying parameters can be challenging; therefore, a Finite Element Analysis model of the filter was conducted using COMSOL ® Multiphysics to analyze the effects of fire. Finite Element Analysis (FEA) modelling offers several opportunities: researchers can quickly and easily consider impacts of potential design changes, material selection, and flow characterization on filter performance. Specifically, this model provides stress references for the sealant at high temperatures. Modeling of full filter assemblies was deemed inefficient given the computational requirements, so a section of three tubes from the assembly was modeled. The model looked at the transient heating and thermomechanical stress development during a 500°C air flow at 6 CFM. Significant stresses were found at the ceramic-metal interfaces of the filter, and conservative temperature profiles at locations of interest were plotted. The model can be used for the development of sealants that minimize stresses at the ceramic-metal interface. Further work on the model would include the full filter assembly and consider heat losses to make more accurate predictions.

Post-treatment of Plasma-Sprayed Amorphous Ceramic Coatings by Spark Plasma Sintering

Czech Academy of Sciences Publication Activity Database

Chráska, Tomáš; Pala, Zdeněk; Mušálek, Radek; Medřický, Jan; Vilémová, Monika

2015-01-01

Roč. 24, č. 4 (2015), s. 637-643 ISSN 1059-9630 R&D Projects: GA ČR GAP107/12/1922 Institutional support: RVO:61389021 Keywords : ceramic s * heat treatment * nanostructured materials Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass Impact factor: 1.568, year: 2015

Characterization of ceramics and semiconductors using nuclear techniques. Final report of a co-ordinated research project

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

With the aim of promoting research and facilitating more extensive application of nuclear techniques for material development, the IAEA established in 1994 a Co-ordinated Research Project (CRP) on Characterization of Ceramics and Semiconductors using Nuclear Techniques. This publication reviews and summarizes recent developments in this field and includes an assessment of the current status and trends in nuclear techniques in characterization of inorganic materials of technological importance. The TECDOC presents new achievements on ceramic superconductor behaviour under neutron induced defects, optimization of structure of mineral gels,m low temperature preparation of fine particles of ferrites, crystal luminescence of ceramic composites with improved plastic properties, thin film defects and detoxification of asbestos. The investigation of chemical composition, phase transitions and magnetic properties of ferrites by Moessbauer spectroscopy is largely developed. The document includes 18 individual contributions, each of them has been indexed and provided with an abstract Refs, figs, tabs

Characterization of ceramics and semiconductors using nuclear techniques. Final report of a co-ordinated research project

International Nuclear Information System (INIS)

1999-03-01

With the aim of promoting research and facilitating more extensive application of nuclear techniques for material development, the IAEA established in 1994 a Co-ordinated Research Project (CRP) on Characterization of Ceramics and Semiconductors using Nuclear Techniques. This publication reviews and summarizes recent developments in this field and includes an assessment of the current status and trends in nuclear techniques in characterization of inorganic materials of technological importance. The TECDOC presents new achievements on ceramic superconductor behaviour under neutron induced defects, optimization of structure of mineral gels,m low temperature preparation of fine particles of ferrites, crystal luminescence of ceramic composites with improved plastic properties, thin film defects and detoxification of asbestos. The investigation of chemical composition, phase transitions and magnetic properties of ferrites by Moessbauer spectroscopy is largely developed. The document includes 18 individual contributions, each of them has been indexed and provided with an abstract

Textured Na x CoO2 Ceramics Sintered from Hydrothermal Platelet Nanocrystals: Growth Mechanism and Transport Properties

Science.gov (United States)

Zhang, Wei; Liu, Pengcheng; Wang, Yifeng; Zhu, Kongjun; Tai, Guoan; Liu, Jinsong; Wang, Jing; Yan, Kang; Zhang, Jianhui

2018-05-01

Nanostructuring is an effective approach to improve thermoelectric (TE) performance, which is caused by the interface and quantum effects on electron and phonon transport. For a typical layered structure such as sodium cobalt (NCO), a highly textured ceramic with nanostructure is beneficial for the carrier transport properties due to the strong anisotropy. In this paper, we established a textured NCO ceramic with highly oriented single crystals in nanoscale. The Na0.6CoO2 platelet crystals were prepared by a one-step hydrothermal method. The growth mechanism was revealed to involve dissolution-recrystallization and exchange reactions. NCO TE ceramics fabricated by a press-aided spark plasma sintering method showed a high degree of texturing, with the platelet crystals basically lying along the in-plane direction perpendicular to the press direction. TE properties of the textured NCO ceramics showed a strong anisotropic behavior. The in-plane electrical conductivity was considerably larger than the out-of-plane data because of fewer grain boundaries and interfaces that existed in the in-plane direction. Moreover, the in-plane Seebeck coefficient was higher because of the anisotropic electronic nature of NCO. Although the in-plane thermal conductivity was high, a prior ZT value was enabled for these NCO ceramics along this direction because of the dominant electrical transport. This finding provides a new approach to prepare highly oriented ceramics.

TiO2 effect on crystallization mechanism and physical properties of nano glass-ceramics of MgO-Al2O3-SiO2 glass system.

Science.gov (United States)

Jo, Sinae; Kang, Seunggu

2013-05-01

The effect of TiO2 on the degree of crystallization, thermal properties and microstructure for MgO-Al2O3-SiO2 glass-ceramics system containing 0-13 wt% TiO2 and 0-1.5 wt% B2O3 in which the cordierite is the main phase was studied. Using Kissinger and Augis-Bennett equations, the activation energy, 510 kJ/mol and Avrami constant, 1.8 were calculated showing the surface-oriented crystallization would be preferred. The alpha-cordierite phase was generated in the glass-ceramics of containing TiO2 of 0-5.6 wt%. However, for the glass-ceramics of TiO2 content above 7 wt%, an alpha-cordierite disappeared and micro-cordierite phase was formed. The glass-ceramics of no TiO2 added had spherical crystals of few tens nanometer size spread in the matrix. As TiO2 content increased up to 5.6 wt%, a lump of dendrite was formed. In the glass-ceramics containing TiO2 7-13 wt%, in which the main phase is micro-cordierite, the dendrite crystal disappeared and a few hundred nanometer sized crystal particles hold tightly each other were generated. The thermal conductivity of glass-ceramics of both a-cordierite and micro-cordierite base decreased with TiO2 contend added. The thermal conductivity of glass-ceramics of 1.5 wt% TiO2 added was 3.4 W/mK which is 36% higher than that of glass-ceramics of no TiO2 added. The sintering temperature for 1.5 wt% TiO2 glass-ceramics was 965 degrees C which could be concluded as to apply to LTCC process for LED packaging.

Luminescent Eu3+-doped transparent alumina ceramics with high hardness

Czech Academy of Sciences Publication Activity Database

Drdlíková, K.; Klement, R.; Hadraba, Hynek; Drdlík, D.; Galusek, D.; Maca, K.

2017-01-01

Roč. 37, č. 14 (2017), s. 4271-4277 ISSN 0955-2219 R&D Projects: GA MŠk(CZ) LQ1601; GA ČR(CZ) GA15-06390S Institutional support: RVO:68081723 Keywords : Aluminia * Europium * Photoluminescence (PL) spectra * Submicrocrystalline powders Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass OBOR OECD: Ceramic s Impact factor: 3.411, year: 2016

Reducing firing of an early pottery making kiln at Batan Grande, Peru: A Moessbauer study

International Nuclear Information System (INIS)

Wagner, U.; Gebhard, R.; Haeusler, W.; Hutzelmann, T.; Riederer, J.; Shimada, I.; Sosa, J.; Wagner, F.E.

1999-01-01

Material from field firing experiments using a 2,700-year old Formative kiln at Batan Grande, Peru, was studied by X-ray diffraction and Moessbauer spectroscopy. The experiments explore the technology involved in producing the gray and black reduced ware for which Cupisnique and other Formative ceramics are justly known. During firing, the iron-bearing compounds in clays undergo characteristic changes which depend on kiln temperature and atmosphere. These changes can be observed in the Moessbauer spectra. By comparing spectra of an appropriate clay fired in field experiments and in the laboratory with the spectra of ancient ceramics, a description of Formative firing techniques in a reducing environment is attempted

Design strategy for a tunable antenna on a partially magnetized ferrite LTCC substrate

KAUST Repository

Ghaffar, Farhan A.; Shamim, Atif; Bray, Joey R.

2014-01-01

Typical microwave simulators cannot accurately predict the behavior of an antenna on a partially magnetized substrate as they assume the substrate to be in fully saturate state. In this work, a new simulation strategy aided by theoretical analysis, is presented to model a tunable patch antenna on a partially magnetized ferrite substrate through a combination of magnetostatic and microwave simulators. An antenna prototype is fabricated in Ferrite LTCC medium to verify the partially magnetized state simulations. The measured results are in close agreement with the simulations, contrary to the case where the substrate is assumed to be in saturation. The prototype designed for 13 GHz exhibits a tuning range of 10 % making it highly suitable for tunable and reconfigurable wireless applications.

Design strategy for a tunable antenna on a partially magnetized ferrite LTCC substrate

KAUST Repository

Ghaffar, Farhan A.

2014-07-01

Typical microwave simulators cannot accurately predict the behavior of an antenna on a partially magnetized substrate as they assume the substrate to be in fully saturate state. In this work, a new simulation strategy aided by theoretical analysis, is presented to model a tunable patch antenna on a partially magnetized ferrite substrate through a combination of magnetostatic and microwave simulators. An antenna prototype is fabricated in Ferrite LTCC medium to verify the partially magnetized state simulations. The measured results are in close agreement with the simulations, contrary to the case where the substrate is assumed to be in saturation. The prototype designed for 13 GHz exhibits a tuning range of 10 % making it highly suitable for tunable and reconfigurable wireless applications.

Ceramic-on-ceramic bearing fractures in total hip arthroplasty: an analysis of data from the National Joint Registry.

Science.gov (United States)

Howard, D P; Wall, P D H; Fernandez, M A; Parsons, H; Howard, P W

2017-08-01

Ceramic-on-ceramic (CoC) bearings in total hip arthroplasty (THA) are commonly used, but concerns exist regarding ceramic fracture. This study aims to report the risk of revision for fracture of modern CoC bearings and identify factors that might influence this risk, using data from the National Joint Registry (NJR) for England, Wales, Northern Ireland and the Isle of Man. We analysed data on 223 362 bearings from 111 681 primary CoC THAs and 182 linked revisions for bearing fracture recorded in the NJR. We used implant codes to identify ceramic bearing composition and generated Kaplan-Meier estimates for implant survivorship. Logistic regression analyses were performed for implant size and patient specific variables to determine any associated risks for revision. A total of 222 852 bearings (99.8%) were CeramTec Biolox products. Revisions for fracture were linked to seven of 79 442 (0.009%) Biolox Delta heads, 38 of 31 982 (0.119%) Biolox Forte heads, 101 of 80 170 (0.126%) Biolox Delta liners and 35 of 31 258 (0.112%) Biolox Forte liners. Regression analysis of implant size revealed smaller heads had significantly higher odds of fracture (chi-squared 68.0, p ceramic type. Liner thickness was not predictive of fracture (p = 0.67). Body mass index (BMI) was independently associated with revision for both head fractures (odds ratio (OR) 1.09 per unit increase, p = 0.031) and liner fractures (OR 1.06 per unit increase, p = 0.006). We report the largest independent study of CoC bearing fractures to date. The risk of revision for CoC bearing fracture is very low but previous studies have underestimated this risk. There is good evidence that the latest generation of ceramic has greatly reduced the odds of head fracture but not of liner fracture. Small head size and high patient BMI are associated with an increased risk of ceramic bearing fracture. Cite this article: Bone Joint J 2017;99-B:1012-19. ©2017 The British Editorial Society of Bone & Joint Surgery.

Co-firing straw and coal in a 150-MWe utility boiler: in situ measurements

DEFF Research Database (Denmark)

Hansen, P. F.B.; Andersen, Karin Hedebo; Wieck-Hansen, K.

1998-01-01

A 2-year demonstration program is carried out by the Danish utility I/S Midtkraft at a 150-MWe PF-boiler unit reconstructed for co-firing straw and coal. As a part of the demonstration program, a comprehensive in situ measurement campaign was conducted during the spring of 1996 in collaboration...... with the Technical University of Denmark. Six sample positions have been established between the upper part of the furnace and the economizer. The campaign included in situ sampling of deposits on water/air-cooled probes, sampling of fly ash, flue gas and gas phase alkali metal compounds, and aerosols as well...... deposition propensities and high temperature corrosion during co-combustion of straw and coal in PF-boilers. Danish full scale results from co-firing straw and coal, the test facility and test program, and the potential theoretical support from the Technical University of Denmark are presented in this paper...

System on Package (SoP) Millimeter Wave Filters for 5G Applications

KAUST Repository

Showail, Jameel

2018-05-01

Bandpass filters are an essential component of wireless communication systems that only transmits frequencies corresponding to the communication band and rejects all other frequencies. As the deployment of 5G draws nearer, first deployments are expected in 2020 [1], the need for viable filters at the new frequency bands becomes more imminent. Size and performance are two critical considerations for a filter that will be used in emerging mobile communication applications. The high frequency of 5G communication, 28 GHz as opposed to sub 6 GHz for nearly all previous communication protocols, means that previously utilized lumped component based solutions cannot be implemented since they are ill-suited for mm-wave applications. The focus of this work is the miniaturization of a high-performance filter. The Substrate Integrated Waveguide (SIW) is a high performance and promising structure and Low Temperature Co-Fired Ceramic (LTCC) is a high-performance material that both can operate at higher frequencies than the technologies used for previous telecommunication generations. To miniaturize the structure, a compact folded four-cavity SIW filter is designed, implemented and tested. The feeding structure is integrated into the filter to exploit the System on Package (SoP) attributes of LTCC and further reduce the total area of the filter individually and holistically when looking at the final integrated system. Two unique three dimensional (3D) integrated SoP LTCC two-stage SIW single cavity filters and one unique four-cavity filter all with embedded planar resonators are designed, fabricated and tested. The embedded resonators create a two-stage effect in a single cavity filter. The better single cavity design provides a 15% fractional bandwidth at a center frequency of 28.12 GHz, and with an insertion loss of -0.53 dB. The fabricated four-cavity filter has a 3-dB bandwidth of .98GHz centered at 27.465 GHz, and with an insertion loss of -2.66 dB. The designs presented

Characterisation of solid recovered fuels for direct co-firing in large-scale PF power plants

Energy Technology Data Exchange (ETDEWEB)

Dunnu, Gregory

2013-04-01

Solid Recovered Fuels are solid fuels prepared from high calorific fractions of non-hazardous waste materials intended to be co-fired in coal power plants and industrial furnaces (CEN/TC 343). They are composed of a variety of materials of which some, although recyclable in theory, may be in a form that makes their recycling an unsound option. The SRF with a typical size range of 3 mm through 25 mm are to be directly co-fired in an existing pulverised coal power plant. In comparison to pulverised coal, the particle size distribution of the SRF is of several magnitudes higher, resulting in a different burnout behaviour. Size reduction of the SRF to a fraction similar to coal is not economically feasible. The aim here is, therefore, the direct co-firing of the solid recovered fuels in the boilers without any further size reduction. This approach, however, bears the risk of incomplete combustion if the injection points of the solid recovered fuels are not optimally selected. Accordingly, the prediction of the burner levels, at which the solid recovered fuels should be injected and whether or not a complete combustion will be achieved under full load condition, is the primary objective of this dissertation. In this research work, laboratory experiments have been conducted to forecast the success of co-firing the SRF in a commercial pulverised coal power plant. It involves the analyses of the fuel and its intermediate chars generated at conditions comparable to boiler conditions to determine some characteristic parameters, namely the burnout time, the aerodynamic lift velocity, the drag coefficient and the apparent densities. The data gathered from the laboratory experiments are transferred to boiler conditions to determine the particle trajectories and the maximum distance likely to travel before they are completely converted in the boiler. Different scenarios are examined and based on the results the best boiler injection points are predicted. Furthermore, an on

Lava ultimate resin nano ceramic for CAD/ CAM: customization case study.

Science.gov (United States)

Koller, M; Arnetzl, G V; Holly, L; Arnetzl, G

2012-01-01

Lava Ultimate Resin Nano Ceramic (RNC) blocks are innovative new CAD/CAM materials that make it possible to achieve superior esthetic results in easy steps. The blocks are made of nano ceramic particles embedded in a highly cured resin matrix. Therefore, composite materials can be used to characterize and adjust resin nano ceramic restorations after milling. The milled RNC restorations can be individualized intra-orally or extra-orally, either before or after insertion. Unlike conventional ceramic restorations, customization and glaze firing is neither necessary nor possible with RNC restorations. This opens up the opportunity for intraoral individualization and adaptation of the restorations.

Field test corrosion experiments in Denmark with biomass fuels Part II Co-firing of straw and coal

DEFF Research Database (Denmark)

Montgomery, Melanie; Larsen, OH

2002-01-01

undertaken where coal has been co-fired with 10% straw and 20% straw (% energy basis) for up to approx. 3000 hours. Two types of exposure were undertaken to investigate corrosion: a) the exposure of metal rings on water/air cooled probes, and b) the exposure of a range of materials built into the existing...... and potassium sulphate. These components give rise to varying degrees of accelerated corrosion. This paper concerns co-firing of straw with coal to reduce the corrosion rate from straw to an acceptable level. A field investigation at Midtkraft Studstrup suspension-fired power plant in Denmark has been...... for 100% straw-firing. The corrosion products and course of corrosion for the various steel types were investigated using light optical and scanning electron microscopy. Catastrophic corrosion due to potassium chloride was not observed. Instead a more modest corrosion rate due to potassium sulphate rich...

FIB/SEM and SEM/EDS microstructural analysis of metal-ceramic and zirconia-ceramic interfaces.

Science.gov (United States)

Massimi, F; Merlati, G; Sebastiani, M; Battaini, P; Menghini, P; Bemporad, E

2012-01-10

Recently introduced FIB/SEM analysis in microscopy seems to provide a high-resolution characterization of the samples by 3D (FIB) cross-sectioning and (SEM) high resolution imaging. The aim of this study was to apply the FIB/SEM and SEM/EDS analysis to the interfaces of a metal-ceramic vs. two zirconia-ceramic systems. Plate samples of three different prosthetic systems were prepared in the dental lab following the manufacturers' instructions, where metal-ceramic was the result of a ceramic veneering (porcelain-fused-to-metal) and the two zirconia-ceramic systems were produced by the dedicated CAD-CAM procedures of the zirconia cores (both with final sintering) and then veneered by layered or heat pressed ceramics. In a FIB/SEM equipment (also called DualBeam), a thin layer of platinum (1 μm) was deposited on samples surface crossing the interfaces, in order to protect them during milling. Then, increasingly deeper trenches were milled by a focused ion beam, first using a relatively higher and later using a lower ion current (from 9 nA to 0.28 nA, 30KV). Finally, FEG-SEM (5KV) micrographs (1000-50,000X) were acquired. In a SEM the analysis of the morphology and internal microstructure was performed by 13KV secondary and backscattered electrons signals (in all the samples). The compositional maps were then performed by EDS probe only in the metal-ceramic system (20kV). Despite the presence of many voids in all the ceramic layers, it was possible to identify: (1) the grain structures of the metallic and zirconia substrates, (2) the thin oxide layer at the metal-ceramic interface and its interactions with the first ceramic layer (wash technique), (3) the roughness of the two different zirconia cores and their interactions with the ceramic interface, where the presence of zirconia grains in the ceramic layer was reported in two system possibly due to sandblasting before ceramic firing.

Ultra-supercritical (USC) technology. The best practical and economic way to reduce CO{sub 2} emissions from coal fired power plants

Energy Technology Data Exchange (ETDEWEB)

Mao, Jianxiong [Tsinghua Univ., Beijing (China). Dept. of Thermal Engineering

2013-07-01

China is the largest coal producer and consumer with largest coal power capacity in the world. By the end of 2010, the total installed power capacity in China was 962,190 MWe, in which coal fired power capacity was 706,630 MWe, accounting for over 73.4%. China has been the largest CO{sub 2} emission country as well and its huge coal power capacity is the largest CO{sub 2} emission source. How does China reduce its CO{sub 2} emissions from coal fired power plants is an austere challenge now we are facing. How does China reduce its CO{sub 2} emissions from coal fired power plants? There are three ways to reduce CO{sub 2} emissions from coal fired power plants: (1) carbon capture and storage (CCS); (2) co-firing biomass with coal; (3) much improvement of efficiency. For the first option of CCS, the technology is still under development and there are still several uncertainties today to be widely used for coal fired power plants in the short term. For the second option of biomass co-firing, it can reduce CO{sub 2} emissions in a way, but it is difficult to implement it in China without strong support of incentive policy. Therefore, the third option of improvement of efficiency is the only but also the best and feasible economic option for China to much reduce CO{sub 2} emissions from coal fired power plants. This paper will discuss how China to take a active policy to strongly promote the application of supercritical (SC)/Ultra supercritical (USC) technology. Only in 4 years from 2007 to 2010, ordered capacity of coal fired SC/USC units was 482 units with installed capacity of 230,060 MWe, in which, 1,000 MWe USC with 600 C steam parameters was almost 100 units with 100,000 MWe in which 33 units have been in operation. Today, China has been a country with the largest SC/USC units and capacity. The fast application of SC/USC units for coal fired power plants has resulted in energy saving and reduction of emissions. The average coal consumption in China reduced from 366

Characterization of granite waste for use in red ceramic

International Nuclear Information System (INIS)

Aguiar, M.C.; Monteiro, S.N.; Vieira, C.M.F.; Borlini, M.C.

2011-01-01

This work aims to study the characterization of the granite waste from the city of Santo Antonio de Padua-RJ for the use in red ceramic. The chemical, physical and morphological characterization of the waste was performed by chemical analysis, X-ray diffraction, particle size distribution, thermal analysis and scanning electron microscopy (SEM). The results indicated that this waste is a material with great potential to be used as a component of ceramic body due to its capacity to act as flux during the firing, and to improve the properties of the ceramic when is incorporate. (author)

Mössbauer analysis of recent ceramic finds from Chavin

Science.gov (United States)

Wagner, U.; Wagner, F. E.; Stockklauser, A.; Salazar, R.; Riederer, J.; Kauffmann-Doig, F.

1986-02-01

A large number of ceramic sherds from Chavin, Peru, as well as recent clay samples from the same region have been studied by Mössbauer spectroscopy. The changes of the Mössbauer spectra of the clay were studied as a function of firing temperature and atmosphere. From a comparison of these data with those form the sherds one can make estimates of the precolumbian firing conditions.

Rat inhalation test with particles from biomass combustion and biomass co-firing exhaust

Science.gov (United States)

Bellmann, B.; Creutzenberg, O.; Ernst, H.; Muhle, H.

2009-02-01

The health effects of 6 different fly ash samples from biomass combustion plants (bark, wood chips, waste wood, and straw), and co-firing plants (coal, co-firing of coal and sawdust) were investigated in a 28-day nose-only inhalation study with Wistar WU rats. Respirable fractions of carbon black (Printex 90) and of titanium dioxide (Bayertitan T) were used as reference materials for positive and negative controls. The exposure was done 6 hours per day, 5 days per week at an aerosol concentration of 16 mg/m3. The MMAD of all fly ash samples and reference materials in the inhalation unit were in the range from 1.5 to 3 μm. The investigations focused predominantly on the analysis of inflammatory effects in the lungs of rats using bronchoalveolar lavage (BAL) and histopathology. Different parameters (percentage of polymorphonuclear neutrophils (PMN), interleukin-8 and interstitial inflammatory cell infiltration in the lung tissue) indicating inflammatory effects in the lung, showed a statistically significant increase in the groups exposed to carbon black (positive control), C1 (coal) and C1+BM4 (co-firing of coal and sawdust) fly ashes. Additionally, for the same groups a statistically significant increase of cell proliferation in the lung epithelium was detected. No significant effects were detected in the animal groups exposed to BM1 (bark), BM2 (wood chips), BM3 (waste wood), BM6 (straw) or titanium dioxide.

Rat inhalation test with particles from biomass combustion and biomass co-firing exhaust

International Nuclear Information System (INIS)

Bellmann, B; Creutzenberg, O; Ernst, H; Muhle, H

2009-01-01

The health effects of 6 different fly ash samples from biomass combustion plants (bark, wood chips, waste wood, and straw), and co-firing plants (coal, co-firing of coal and sawdust) were investigated in a 28-day nose-only inhalation study with Wistar WU rats. Respirable fractions of carbon black (Printex 90) and of titanium dioxide (Bayertitan T) were used as reference materials for positive and negative controls. The exposure was done 6 hours per day, 5 days per week at an aerosol concentration of 16 mg/m 3 . The MMAD of all fly ash samples and reference materials in the inhalation unit were in the range from 1.5 to 3 μm. The investigations focused predominantly on the analysis of inflammatory effects in the lungs of rats using bronchoalveolar lavage (BAL) and histopathology. Different parameters (percentage of polymorphonuclear neutrophils (PMN), interleukin-8 and interstitial inflammatory cell infiltration in the lung tissue) indicating inflammatory effects in the lung, showed a statistically significant increase in the groups exposed to carbon black (positive control), C1 (coal) and C1+BM4 (co-firing of coal and sawdust) fly ashes. Additionally, for the same groups a statistically significant increase of cell proliferation in the lung epithelium was detected. No significant effects were detected in the animal groups exposed to BM1 (bark), BM2 (wood chips), BM3 (waste wood), BM6 (straw) or titanium dioxide.

Use of basaltic waste as red ceramic raw material

Directory of Open Access Journals (Sweden)

T. M. Mendes

Full Text Available Abstract Nowadays, environmental codes restrict the emission of particulate matters, which result in these residues being collected by plant filters. This basaltic waste came from construction aggregate plants located in the Metropolitan Region of Londrina (State of Paraná, Brazil. Initially, the basaltic waste was submitted to sieving (< 75 μm and the powder obtained was characterized in terms of density and particle size distribution. The plasticity of ceramic mass containing 0%, 10%, 20%, 30%, 40% and 50% of basaltic waste was measured by Atterberg method. The chemical composition of ceramic formulations containing 0% and 20% of basaltic waste was determined by X-ray fluorescence. The prismatic samples were molded by extrusion and fired at 850 °C. The specimens were also tested to determine density, water absorption, drying and firing shrinkages, flexural strength, and Young's modulus. Microstructure evaluation was conducted by scanning electron microscopy, X-ray diffraction, and mercury intrusion porosimetry. Basaltic powder has similar physical and chemical characteristics when compared to other raw materials, and contributes to ceramic processing by reducing drying and firing shrinkage. Mechanical performance of mixtures containing basaltic powder is equivalent to mixtures without waste. Microstructural aspects such as pore size distribution were modified by basaltic powder; albite phase related to basaltic powder was identified by X-ray diffraction.

Oxygen-Fired CO{sub 2} Recycle for Application to Direct CO{sub 2} Capture form Coal-Fired Power Plants

Energy Technology Data Exchange (ETDEWEB)

Thomas Gale

2010-09-26

The Southern Research/Southern Company 1 MWth Pilot-Scale Coal-Fired Test Facility was successfully retrofit to fire in either the traditional air-fired mode or with 100% oxygen and recycled flue gas, with a fully integrated feedback and control system, including oxygen and recycled flue gas modulation during startup, transfer, and shutdown, safety and operational interlocks, and data acquisition. A MAXON Staged Oxygen Burner for Oxy-Coal Applications produced a stable flame over a significant range of firing turn-down, staging, and while firing five different U.S. coal types. The MAXON burner design produces lower flame temperatures than for air firing, which will enable (A) Safe operation, (B) Reduction of recycle flow without concern about furnace flame temperatures, and (C) May likely be affective at reducing slagging and fouling in the boiler and super heater at full-scale Power Plants. A CFD model of the Oxy-fired Combustion Research Facility (OCRF) was used to predict the flame geometry and temperatures in the OCRF and make a comparison with the air-fired case. The model predictions were consistent with the experimental data in showing that the MAXON burner fired with oxygen produced lower flame temperatures than the air-fired burner while firing with air.

Development of tungsten coatings for the corrosion protection of alumina-based ceramics

International Nuclear Information System (INIS)

Arons, R.M.; Dusek, J.T.; Hafstrom, J.W.

1979-01-01

A means of applying tungsten coatings to an alumina based ceramic is described. A slurry of pure tungsten was prepared and applied by brush coating or slip casting on the alumina-3 wt % Yt small crucible. The composite was fired and a very dense ceramic crucible with a crack free tungsten coating was produced

Microstructure and electrical properties of (1−x)[0.8Bi_0_._5Na_0_._5TiO_3-0.2Bi_0_._5K_0_._5TiO_3]-xBiCoO_3 lead-free ceramics

International Nuclear Information System (INIS)

Wang, Ting; Chen, Xiao-ming; Qiu, Yan-zi; Lian, Han-li; Chen, Wei-ting

2017-01-01

The (1−x)[0.8Bi_0_._5Na_0_._5TiO_3-0.2Bi_0_._5K_0_._5TiO_3]-xBiCoO_3 (x = 0, 0.02, 0.05, abbreviated as BNKT, BNKT-002Co, BNKT-005Co, respectively) lead-free ferroelectric ceramics were prepared via the solid state reaction method. The phase structure, microstructure, dielectric, ferroelectric, pyroelectric, and piezoelectric properties of the ceramics were investigated comparatively by using a combination of characterization techniques. All the samples exhibit typical X-ray diffraction peaks of ABO_3 perovskite structure. The doping of BiCoO_3 causes a decrease in lattice parameters and an increase in grain size of the ceramics. The Raman spectroscopy results suggest a lattice distortion due to the doping. It is found that BNKT-002Co and BNKT-005Co have higher depolarization temperatures compared with BNKT. The Curie-Weiss law and modified Curie-Weiss law explored a diffuse phase transition character for all the samples. The results of ultraviolet–visible diffuse reflectance suggests that BiCoO_3-doped ceramics possess higher defect concentration. The impedance analysis shows a temperature dependent relaxation behavior, and the activation energy for the electrical responses varies with the change of BiCoO_3 amount. The ferroelectric and piezoelectric properties of the ceramics decrease due to the doping of BiCoO_3. Based on the results of the Rayleigh analysis, it was suggested that the differences in the electrical properties among the ceramics are closely related to the change in oxygen vacancy concentration. - Highlights: • BNKT-xCo ceramics were prepared by solid-state reaction method. • Electrical properties of BNKT ceramics are changed by the doping of BiCoO_3. • The doping causes a decrease in lattice parameters and an increase in grain size. • T_d of the ceramics increases with increasing x. • Oxygen vacancies play key role in determining electrical properties of the ceramics.

Protection against fire and high temperature by using porous media and water

International Nuclear Information System (INIS)

Yano, T.; Ochi, M.; Snya, S.

1991-01-01

In this paper the protection method against the fire and high temperature under the disaster environments is developed and examined by utilizing the transpiration cooling to maintain the objectives at the room temperature. A room model installed by thermal protection panel for security heaven to which the people are able to escape from the fire in safety. The cooling structure is mainly composed of porous media which is made by thin ceramic paper, and the reinforced ceramic paper. The experimental verification of the room and cable models shows that the thermal protection by transpiration of water have good ability to keep inside at the room temperature even if in the violent fire. It is also clarified that the thermal protection technology by transpiration is expective to defend the room, building, cable, safety equipment, information system and etc., from the fire

Future CO2 emissions and electricity generation from proposed coal-fired power plants in India

Science.gov (United States)

Fofrich, R.; Shearer, C.; Davis, S. J.

2017-12-01

India represents a critical unknown in global projections of future CO2 emissions due to its growing population, industrializing economy, and large coal reserves. In this study, we assess existing and proposed construction of coal-fired power plants in India and evaluate their implications for future energy production and emissions in the country. In 2016, India had 369 coal-fired power plants under development totaling 243 gigawatts (GW) of generating capacity. These coal-fired power plants would increase India's coal-fired generating capacity by 123% and would exceed India's projected electricity demand. Therefore, India's current proposals for new coal-fired power plants would be forced to retire early or operate at very low capacity factors and/or would prevent India from meeting its goal of producing at least 40% of its power from renewable sources by 2030. In addition, future emissions from proposed coal-fired power plants would exceed India's climate commitment to reduce its 2005 emissions intensity 33% - 35% by 2030.

FIVE YEAR OUTCOMES OF CERAMIC-ОN-CERAMIC AND CERAMIC-ОN-POLYETHYLENE BEARINGS IN HIP JOINT REPLACEMENT

Directory of Open Access Journals (Sweden)

V. Yu. Murylev

2017-01-01

Full Text Available In view of the increasing number of hip joint replacement volume there remains the key issue of improving prosthesis survivorship which directly depends on the friction couple. Material and methods. The authors have analyzed five year outcomes of two bearing types (head and insert used in hip replacement: ceramic-on-ceramic (CoC in 324 patients and ceramic-on-polyethylene (CoP in 300 patients. Totally 550 patients were operated in the period starting 2010 till 2014, including 74 patients underwent bilateral hip replacement. The authors divided patients based on gender and also into three age groups: 20-40, 41-60 and 61-80 years old. The largest group comprised 156 women aged 41-60 years (28.4%. Additional grouping of patients was made based on gender, age and bearing diameter.36 mm diameter bearing was characterized of the most frequent use. Functional outcomes were assessed by Harris Hip Score. Statistical analysis was made with Statistica 10 software. Statistical significant was observed at p<0.05.Results.28 mm diameter bearing were rarely (19.5% applied and mainly in women which is related to need for use of smaller acetabulum components and inability to implant a larger insert.36 mm diameter bearing were used most frequently, CoC articulation of36 mm was used in men in 34% of cases and in women – in 18.12% of cases.40 mm articulations were implanted in women two times less than in men which is related to a smaller diameter of acetabulum in women. Generally, CoC bearings were implanted more often in men which can be explained by a bigger social demand as well as a higher anti-luxation stability of large diameter bearings. Dislocations of implants occurred in 5 (0.91% patients: in 4 patients with CoP bearingand in one patient with CoC articulation. Four revision procedures (0.64% were made due to deep periprosthetic infection: two surgeries in each group. Harris Hip Score evaluation in CoC group demonstrated excellent and good outcomes in

Archaeometric studies of ceramics from the Sao Paulo II archaeological site

International Nuclear Information System (INIS)

Rogerio Baria; Munita, C.S.; Cano, N.F.; Tatumi, S.H.; Silva-Carrera, B.N.; Shigueo Watanabe; Neves, E.G.

2015-01-01

This paper aims at studying the elementary chemical composition of 70 ceramic fragments from the Sao Paulo II archaeological site by instrumental neutron activation analysis. The concentration data was studied next using multivariate statistical methods, such as cluster analysis, principal component analysis and discriminant analysis. The results showed three different chemical groups of samples regarding the similarity/dissimilarity between the samples. Ceramics from each group have been selected and dated using thermoluminescence. The firing temperature of the ceramics was determined by electron paramagnetic resonance. (author)

A continuing study of electrically conducting ceramics. Final report, August 9, 1978 - March 31, 1979

Energy Technology Data Exchange (ETDEWEB)

1979-01-01

A series of 36 perovskite ceramics based on SrZrO/sub 3/ has been prepared and investigated as potential materials for electrodes for MHD systems using hydrogen as a fuel. All ceramics prepared were found to be relatively dark in color, indicating optical absorptions associated with the existence of conduction electrons. Many were found to be soft and crumbly after firing at 1400/sup 0/ or 1500/sup 0/C, but became hard and often quite shiny when fired at 1650/sup 0/C using a special graphite induction furnace. In most cases, this increase in hardness was also accompanied by a significant density increase. Most ceramics were found to be composed of second perovskite structures, i.e. manganates of Ba, Ca, Sr or La, in addition to the zirconate phase. Their room temperature electrical resistivity was determined by the van der Paaw method. Results show that resistivity falls below 100 ohm-cm (the value acceptable for MHD electrodes) for certain ceramics of the types tested. The resistivity value was found to vary significantly with firing temperature; this can be correlated with the crystal structures and number of phases within the ceramic. Weight loss measurements done at 1440/sup 0/C have enabled three ceramics to be identified as potential materials for thermoelectric converters requiring high temperature structural and chemical stability in oxidizing atmospheres. An appendix reviews the current status of the basis for development of perovskite ceramics and specific materials are discussed on the basis of relevant thermoelectric properties. Also included is a review of semiconductor thermocouples and of materials selection for insulators and electrodes for use in MHD systems. 91 refs., 3 figs., 10 tabs.

Sintering mechanism of blast furnace slag-kaolin ceramics

International Nuclear Information System (INIS)

Mostafa, Nasser Y.; Shaltout, Abdallah A.; Abdel-Aal, Mohamed S.; El-maghraby, A.

2010-01-01

A general ceramics processing scheme by cold uniaxial pressing and conventional sintering process have been used to prepare ceramics from mixtures of blast furnace slag (BFS) and kaolin (10%, 30% and 50% kaolin). The properties of the ceramics were studied by measuring linear shrinkage, bulk density, apparent porosity and mechanical properties of samples heated at temperatures from 800 o C to 1100 o C. The formed crystalline phases were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). Slag melt formed at relatively low temperatures (800-900 o C) modified the sintering process to liquid phase sintering mechanism. Combination of BFS with 10% kaolin gave the highest mechanical properties, densification and shrinkage at relatively low firing temperatures. The crystalline phases were identified as gehlenite (Ca 2 Al 2 SiO 7 ) in both BFS and BFS with 10% kaolin samples. Anorthite (CaAl 2 Si 2 O 8 ) phase increased with increasing kaolin contents. In the case of kaolin-rich mixtures (30% and 50% kaolin), increased expansion took place during firing at temperatures in the range 800-1000 o C. This effect could be attributed to the entrapment of released gases.

Reverse engineering the ancient ceramic technology based on X-ray fluorescence spectromicroscopy

Energy Technology Data Exchange (ETDEWEB)

Sciau, Philippe; Leon, Yoanna; Goudeau, Philippe; Fakra, Sirine C.; Webb, Sam; Mehta, Apurva

2011-07-06

We present results of X-ray fluorescence (XRF) microprobe analyses of ancient ceramic cross-sections aiming at deciphering the different firing protocols used for their production. Micro-focused XRF elemental mapping, Fe chemical mapping and Fe K-edge X-ray absorption near edge structure spectroscopy were performed on pre-sigillata ceramics from southern Gaul, and terra Sigillata vessels from Italy and southern Gaul. Pieces from the different workshops and regions showed significant difference in the starting clay material, clay conditioning and kiln firing condition. By contrast, sherds from the same workshop exhibited more subtle differences and possible misfirings. Understanding the precise firing conditions and protocols would allow recreation of kilns for various productions. Furthermore, evolution and modification of kiln design would shed some light on how ancient potters devised solutions to diverse technological problems they encountered.

Early Pottery Making in Northern Coastal Peru. Part IV: Moessbauer Study of Ceramics from Huaca Sialupe

International Nuclear Information System (INIS)

Shimada, I.; Haeusler, W.; Jakob, M.; Montenegro, J.; Riederer, J.; Wagner, U.

2003-01-01

We report on an interdisciplinary study of ceramic material excavated in 1999 and 2001 at a 1000-year old ceramic and metal production site, located at Huaca Sialupe in the La Leche valley on the north coast of Peru and dating to the Middle Sican period (AD 900-1100). Sherds of Sican red- and blackware, numerous moulds, several kilns and other evidence of pottery making were found. The pottery, in particular, is famous for its fine texture and perfect black surface finish. In addition, some clay lumps and sherds of unfired Sican pottery were excavated. Within the same workshop several large inverted ceramic urns used as furnaces were found together with Middle Sican metal working tools and debris. Various physical methods were applied to investigate this material. The ancient firing procedures could be elucidated by comparing the spectra observed for the ancient sherds with model spectra of laboratory and field fired clay samples. This shows that the fine ware made at Huaca Sialupe was intentionally fired under strongly reducing conditions at temperatures up to 900 o C. Reoxidation at the end of the reducing firing took place only occasionally. Less care was taken in firing moulds used for pottery making.

Optical, mechanical and fractographic response of transparent alumina ceramics on erbium doping

Czech Academy of Sciences Publication Activity Database

Drdlík, D.; Drdlíková, K.; Hadraba, Hynek; Máca, K.

2017-01-01

Roč. 37, č. 14 (2017), s. 4265-4270 ISSN 0955-2219 R&D Projects: GA MŠk(CZ) LQ1601; GA ČR(CZ) GA15-06390S Institutional support: RVO:68081723 Keywords : Alumina * Erbia * Fractography * Hardness * Transparency Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 3.411, year: 2016

Logistics, Costs, and GHG Impacts of Utility-Scale Co-Firing with 20% Biomass

Energy Technology Data Exchange (ETDEWEB)

Nichol, Corrie Ian [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2013-06-01

This study analyzes the possibility that biopower in the U.S. is a cost-competitive option to significantly reduce greenhouse gas emissions. In 2009, net greenhouse gas (GHG) emitted in the United States was equivalent to 5,618 million metric tons CO₂, up 5.6% from 1990 (EPA 2011). Coal-fired power generation accounted for 1,748 million metric tons of this total. Intuitively, life-cycle CO₂ emissions in the power sector could be reduced by substituting renewable biomass for coal. If just 20% of the coal combusted in 2009 had been replaced with biomass, CO₂ emissions would have been reduced by 350 million metric tons, or about 6% of net annual GHG emission. This would have required approximately 225 million tons of dry biomass. Such an ambitious fuel substitution would require development of a biomass feedstock production and supply system tantamount to coal. This material would need to meet stringent specifications to ensure reliable conveyance to boiler burners, efficient combustion, and no adverse impact on heat transfer surfaces and flue gas cleanup operations. Therefore, this report addresses the potential cost/benefit tradeoffs of co-firing 20% specification-qualified biomass (on an energy content basis) in large U.S. coal-fired power plants. The dependence and sensitivity of feedstock cost on source of material, location, supply distance, and demand pressure was established. Subsequently, the dependence of levelized cost of electricity (LCOE) on feedstock costs, power plant feed system retrofit, and impact on boiler performance was determined. Overall life-cycle assessment (LCA) of greenhouse gas emissions saving were next evaluated and compared to wind and solar energy to benchmark the leading alternatives for meeting renewable portfolio standards (or RPS).

Wear Performance of Sequentially Cross-Linked Polyethylene Inserts against Ion-Treated CoCr, TiNbN-Coated CoCr and Al2O3 Ceramic Femoral Heads for Total Hip Replacement

Directory of Open Access Journals (Sweden)

Christian Fabry

2015-02-01

Full Text Available The aim of the present study was to evaluate the biotribology of current surface modifications on femoral heads in terms of wettability, polyethylene wear and ion-release behavior. Three 36 mm diameter ion-treated CoCr heads and three 36 mm diameter TiNbN-coated CoCr heads were articulated against sequentially cross-linked polyethylene inserts (X3 in a hip joint simulator, according to ISO 14242. Within the scope of the study, the cobalt ion release in the lubricant, as well as contact angles at the bearing surfaces, were investigated and compared to 36 mm alumina ceramic femoral heads over a period of 5 million cycles. The mean volumetric wear rates were 2.15 ± 0.18 mm3·million cycles−1 in articulation against the ion-treated CoCr head, 2.66 ± 0.40 mm3·million cycles−1 for the coupling with the TiNbN-coated heads and 2.17 ± 0.40 mm3·million cycles−1 for the ceramic heads. The TiNbN-coated femoral heads showed a better wettability and a lower ion level in comparison to the ion-treated CoCr heads. Consequently, the low volumes of wear debris, which is comparable to ceramics, and the low concentration of metal ions in the lubrication justifies the use of coated femoral heads.

Evaluation of PCDD/Fs emissions during ceramic production: a laboratory study.

Science.gov (United States)

Lu, Mang; Luo, Yi-Jing; Zhang, Zhong-Zhi; Xiao, Meng; Zhang, Min

2012-08-30

Because of the ubiquity of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in kaolinitic clays, the ceramic industry is considered to be a potential source of PCDD/Fs. However, studies on the emission of PCDD/Fs from ceramic production are still very scarce. In this study, PCDD/Fs emissions during ceramic production were investigated in an electric laboratory batch kiln. The results showed that the PCDD/Fs were completely removed from the ceramic pieces after 30 min of firing at the peak temperature of 1200°C. Nevertheless, on the mass and international toxic equivalent basis, 27.5% and 46.2% of the total PCDD/Fs amount in the raw clay were released into the atmosphere during firing, respectively. These PCDD/Fs were emitted into the air before the temperature was elevated to a level high enough for their destruction. Dechlorination reactions generated a broad distribution within the PCDD/Fs congeners including a variety of non-2,3,7,8-substituted ones. The emission of PCDD/Fs was decreased to 16.3 wt.% of the total PCDD/Fs amount in the raw clay, when the initial kiln temperature was enhanced to 600°C. The emission of PCDD/Fs could be reduced significantly in the presence of a glaze coating on the ceramic test piece. These results indicated that ceramic production is an un-neglectable source of PCDD/Fs in the environment. Copyright © 2012 Elsevier B.V. All rights reserved.

Analysis of Co-Effects on Air Pollutants and CO2 Emissions Generated by End-of-Pipe Measures of Pollution Control in China’s Coal-Fired Power Plants

Directory of Open Access Journals (Sweden)

Haijun Zhao

2017-03-01

Full Text Available China is now facing great challenges resulting from climate change and air pollution, driven by the processes of industrialization and urbanization. Greenhouse gas and air pollutant emissions produced by the coal-fired power industry represent approximately 70% of the total emissions in China’s industrial sector. In this study, 39 coal-fired power plants built in China between 2014 and 2015 were analyzed in regards to the co-effects oncarbon dioxide and air pollutant emissions generated directly and indirectly by end-of-pipe measures of pollution control. After completing the quantitative analysis with input data from 83units of power plants, we found that co-effects were positive only for air pollutant reductions through the implementation of desulfurization, denitrification, and dedusting measures, but co-effects were negative for carbon dioxide production because of the corresponding electricity use and chemical reactions that led to the increases in carbon dioxide emissions. We also performed an assessment of the synergistic coefficients to better understand the degree of co-effects. It will be important for researchers to take a comprehensive view of China’s coal-fired power plants and look for solutions that can maximize positive co-effects and achieve overall co-benefits of reductions in greenhouse gas emissions and air pollutants.

Co-firing coal and biomass blends and their influence on the post-combustion CO2 capture installation

Directory of Open Access Journals (Sweden)

Więckol-Ryk Angelika

2017-01-01

Research proved that co-firing of biomass in fossil fuel power plants is beneficial for PCC process. It may also reduce the corrosion of CO2 capture installation. The oxygen concentration in the flue gases from hard coal combustion was comparable with the respective value for a fuel blend of biomass content of 20% w/w. It was also noted that an increase in biomass content in a sample from 20 to 40 % w/w increased the concentration of oxygen in the flue gas streams. However, this concentration should not have a significant impact on the rate of amine oxidative degradation.

A systematic approach to assessing measurement uncertainty for CO2 emissions from coal-fired power plants

DEFF Research Database (Denmark)

Wagner, Claas; Esbensen, Kim

2011-01-01

An augmented measurement uncertainty approach for CO2 emissions from coal-fired power plants with a focus on the often forgotten contributions from sampling errors occurring over the entire fuel-to-emission pathway is presented. Current methods for CO2 emission determination are evaluated in detail......, from which a general matrix scheme is developed that includes all factors and stages needed for total CO2 determination, which is applied to the monitoring plan of a representative medium-sized coal-fired power plant. In particular sampling involved significant potential errors, as identified...... of these three materials were also given full attention. A systematic error (bias) is present in the current sampling approach, which increases the present uncertainty estimate unnecessarily. For both primary sampling and analytical sample extraction steps, random variations, which hitherto only have been...

The influence of coal bottom ash and tincal (boron mineral) additions on the physical and microstructures of ceramic bodies

Energy Technology Data Exchange (ETDEWEB)

Bayca, S.U.; Batar, T.; Sayin, E.; Solak, O.; Kahraman, B. [Celal Bayar University, Manisa (Turkey). Soma Vocational School

2008-07-01

In this paper, the influence of coal bottom ash and tincal additions on the physical properties and microstructures of the standard wall tile body composition was investigated. Water absorption, fang strength, dry and fired shrinkage tests of the incorporated ceramic bodies and reference body were done. Microstructures of sintered tiles were analyzed using a scanning electron microscope (SEM). The results show that tincal additions to the ceramic body improved the physical properties of the tiles. As a result, tincal can be used as a flux material in the ceramic bodies due to its favorable effects on the water absorption and fired strength. The results revealed that bottom ash can be used in the ceramic tile body composition. When bottom ash was used in the ceramic industry, environmental hazards of bottom ash are inhibited. Furthermore, bottom ash is transformed to an economic product.

Fabrication of low temperature cofired ceramic (LTCC) chip couplers for high frequencies : I. Effect of binder burnout process on the formation of electrode line

Energy Technology Data Exchange (ETDEWEB)

Cho, N.T.; Shim, K.B.; Lee, S.W. [Hanyang University, Seoul (Korea); Koo, K.D. [K-Cera Inc., Yongin (Korea)

1999-06-01

In the fabrication of ceramic chip couplers for high frequency applications such as the mobile communication equipment, the formation of electrode lines and Ag diffusion were investigated with heat treatment conditions for removing organic binders. The deformation and densification of the electrode line greatly depended on the binder burnout process due to the overlapped temperature zone near 400{sup o} C of the binder dissociation and the solid phase sintering of the silver electrode. Ag ions were diffused into the glass ceramic substrate. The Ag diffusion was led by the glassy phase containing Pb ions rather than by the crystalline phase containing Ca ions. The fact suggests that the Ag diffusion could be controlled by managing the composition of the glass ceramic substrate. 9 refs., 10 figs., 1 tab.

Using mixture design of experiments to assess the environmental impact of clay-based structural ceramics containing foundry wastes

Energy Technology Data Exchange (ETDEWEB)

Coronado, M. [Department of Chemistry and Process and Resources Engineering, University of Cantabria, 39005 Santander (Spain); Department of Materials and Ceramics Engineering (CICECO), University of Aveiro, 3810-193 Aveiro (Portugal); Segadães, A.M. [Department of Materials and Ceramics Engineering (CICECO), University of Aveiro, 3810-193 Aveiro (Portugal); Andrés, A., E-mail: andresa@unican.es [Department of Chemistry and Process and Resources Engineering, University of Cantabria, 39005 Santander (Spain)

2015-12-15

Highlights: • Modelling of the environmental risk in terms of clay and by-products contents. • M-DoE and response surface plots enable quick comparison of three ceramic processes. • Basicity of the mixture increases the leaching, especially at low firing temperatures. • Liquid phase content plays a major role decreasing the leaching of Cr and Mo. • Together, M-DoE and phase diagrams enable better prediction of pollutants leaching. - Abstract: This work describes the leaching behavior of potentially hazardous metals from three different clay-based industrial ceramic products (wall bricks, roof tiles, and face bricks) containing foundry sand dust and Waelz slag as alternative raw materials. For each product, ten mixtures were defined by mixture design of experiments and the leaching of As, Ba, Cd, Cr, Cu, Mo, Ni, Pb, and Zn was evaluated in pressed specimens fired simulating the three industrial ceramic processes. The results showed that, despite the chemical, mineralogical and processing differences, only chrome and molybdenum were not fully immobilized during ceramic processing. Their leaching was modeled as polynomial equations, functions of the raw materials contents, and plotted as response surfaces. This brought to evidence that Cr and Mo leaching from the fired products is not only dependent on the corresponding contents and the basicity of the initial mixtures, but is also clearly related with the mineralogical composition of the fired products, namely the amount of the glassy phase, which depends on both the major oxides contents and the firing temperature.

Hydrogen separation from high temperature CO-containing syn-gas flow using molecular ceramic membranes

Energy Technology Data Exchange (ETDEWEB)

Soudarev, A.; Konakov, G.; Souryaninov, A.; Molchanov, A. [Boyko Research Engineering Ceramic Heat Engines Center Ltd., St. Petersburg (Russian Federation); Lelait, L.; Stevens, P.H. [European Inst. for Power Studies, Karlsruhe (Germany)

2006-07-01

Poisoning of the platinum (Pt) metals used as catalysts for proton exchange membrane fuel cells (PEMFCs) can negatively impact on PEMFC operation efficiency. In order to address this issue, a supply of hydrogen with a carbon monoxide (CO) admixtures is required. This paper provided details of a new type of molecular ceramic membrane (MCM) that allows the separation of hydrogen (H{sub 2}) from the hydrocarbon fuel reforming products that contain CO and has higher temperature and pressure capacity than other membranes. After various tests, alumo-magnesium spinel (AMS) was selected as the most promising porous material for the ceramic multi-layer membrane. The crystalline structure of the AMS showed good thermo-dynamic stability during tests that ranged between 20 and 1400 degrees C, as well as a chemical resistance relative to the effects of the aggressive fuel cell environment, and no exposure to the oxidation-recovery processes in the CO and H{sub 2} flow. The macroporous substrate of the AMS and the membrane selection layers have the same composition. The formation of the carrier was conducted by a semi-dry molding on a hydraulic press. Formation of the nano-porous structure in the carrier macro-pores by the polysilicon acid sol solution treatment allowed the synthesis of the amorphous silica and crystobalite crystals with a developed surface and nano-dimension subporosity. Test results have shown that the MCM has optimum penetrability and selectivity values as well as admissible thermo-mechanical properties. H{sub 2} flow through the membrane was 1.5-1.7 times greater than the CO flow. It was concluded that the AMS-based membrane devices will increase the efficiency of the PEMFC power plants and reduce their degradation capacity. 2 refs., 1 tab., 1 fig.

Zirconia-based colors for ceramic glazes

International Nuclear Information System (INIS)

Eppler, R.A.

1977-01-01

The history of color development for use in ceramic glazes is outlined. The most significant modern development is based on zirconia and zircon. These materials have gained increasing acceptance in the industry since their introduction in the late 1950's and early 1960's, due to their superior stability during firing of the glaze

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.

ENVIRONMENTAL AND SUSTAINABLE TECHNOLOGY EVALUATION: BIOMASS CO-FIRING IN INDUSTRIAL BOILERS--UNIVERSITY OF IOWA

Science.gov (United States)

The U.S. EPA operates the Environmental and Sustainable Technology Evaluation (ESTE) program to facilitate the deployment of innovative technologies through performance verification and information dissemination. This ESTE project involved evaluation of co-firing common woody bio...

Ceramic heat exchangers. (Latest citations from the NTIS bibliographic database). Published Search

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-08-01

The bibliography contains citations concerning the development, fabrication, and performance of ceramic heat exchangers. References discuss applications in coal-fired gas turbine power plants. Topics cover high temperature corrosion resistance, fracture properties, nondestructive evaluations, thermal shock and fatigue, silicon carbide-based ceramics, and composite joining. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

Early Pottery Making in Northern Coastal Peru. Part IV: Mössbauer Study of Ceramics from Huaca Sialupe

Science.gov (United States)

Shimada, I.; Häusler, W.; Jakob, M.; Montenegro, J.; Riederer, J.; Wagner, U.

2003-09-01

We report on an interdisciplinary study of ceramic material excavated in 1999 and 2001 at a 1000-year old ceramic and metal production site, located at Huaca Sialupe in the La Leche valley on the north coast of Peru and dating to the Middle Sicán period (AD 900-1100). Sherds of Sicán red- and blackware, numerous moulds, several kilns and other evidence of pottery making were found. The pottery, in particular, is famous for its fine texture and perfect black surface finish. In addition, some clay lumps and sherds of unfired Sicán pottery were excavated. Within the same workshop several large inverted ceramic urns used as furnaces were found together with Middle Sicán metal working tools and debris. Various physical methods were applied to investigate this material. The ancient firing procedures could be elucidated by comparing the spectra observed for the ancient sherds with model spectra of laboratory and field fired clay samples. This shows that the fine ware made at Huaca Sialupe was intentionally fired under strongly reducing conditions at temperatures up to 900°C. Reoxidation at the end of the reducing firing took place only occasionally. Less care was taken in firing moulds used for pottery making.

Soil surface CO2 flux in a boreal black spruce fire chronosequence

Science.gov (United States)

Wang, Chuankuan; Bond-Lamberty, Ben; Gower, Stith T.

2003-02-01

Understanding the effects of wildfire on the carbon (C) cycle of boreal forests is essential to quantifying the role of boreal forests in the global carbon cycle. Soil surface CO2 flux (Rs), the second largest C flux in boreal forests, is directly and indirectly affected by fire and is hypothesized to change during forest succession following fire. The overall objective of this study was to measure and model Rs for a black spruce (Picea mariana [Mill.] BSP) postfire chronosequence in northern Manitoba, Canada. The experiment design was a nested factorial that included two soil drainage classes (well and poorly drained) × seven postfire aged stands. Specific objectives were (1) to quantify the relationship between Rs and soil temperature for different aged boreal black spruce forests in well-drained and poorly drained soil conditions, (2) to examine Rs dynamics along postfire successional stands, and (3) to estimate annual soil surface CO2 flux for these ecosystems. Soil surface CO2 flux was significantly affected by soil drainage class (p = 0.014) and stand age (p = 0.006). Soil surface CO2 flux was positively correlated to soil temperature (R2 = 0.78, p aged stand combination. Soil surface CO2 flux was significantly greater at the well-drained than the poorly drained stands (p = 0.007) during growing season. Annual soil surface CO2 flux for the 1998, 1995, 1989, 1981, 1964, 1930, and 1870 burned stands averaged 226, 412, 357, 413, 350, 274, and 244 g C m-2 yr-1 in the well-drained stands and 146, 380, 300, 303, 256, 233, and 264 g C m-2 yr-1 in the poorly drained stands. Soil surface CO2 flux during the winter (from 1 November to 30 April) comprised from 5 to 19% of the total annual Rs. We speculate that the smaller soil surface CO2 flux in the recently burned than the older stands is mainly caused by decreased root respiration.

Influence of porcelain firing and cementation on the marginal adaptation of metal-ceramic restorations prepared by different methods.

Science.gov (United States)

Kaleli, Necati; Saraç, Duygu

2017-05-01

Marginal adaptation plays an important role in the survival of metal-ceramic restorations. Porcelain firings and cementation may affect the adaptation of restorations. Moreover, conventional casting procedures and casting imperfections may cause deteriorations in the marginal adaptation of metal-ceramic restorations. The purpose of this in vitro study was to compare the marginal adaptation after fabrication of the framework, porcelain application, and cementation of metal-ceramic restorations prepared by using the conventional lost-wax technique, milling, direct metal laser sintering (DMLS), and LaserCUSING, a direct process powder-bed system. Alterations in the marginal adaptation of the metal frameworks during the fabrication stages and the precision of fabrication methods were evaluated. Forty-eight metal dies simulating prepared premolar and molar abutment teeth were fabricated to investigate marginal adaptation. They were divided into 4 groups (n=12) according to the fabrication method used (group C serving as the control group: lost-wax method; group M: milling method; group LS: DMLS method; group DP: direct process powder-bed method). Sixty marginal discrepancy measurements were recorded separately on each abutment tooth after fabrication of the framework, porcelain application, and cementation by using a stereomicroscope. Thereafter, each group was divided into 3 subgroups according to the measurements recorded in each fabrication stage: subgroup F (framework), subgroup P (porcelain application), and subgroup C (cementation). Data were statistically analyzed with univariate analysis of variance (followed by 1-way ANOVA and Tamhane T2 test (α=.05). The lowest marginal discrepancy values were observed in restorations prepared by using the direct process powder-bed method, and this was significantly different (Pdirect process powder-bed method is quite successful in terms of marginal adaptation. The marginal discrepancy increased after porcelain application

KNN–NTK composite lead-free piezoelectric ceramic

Energy Technology Data Exchange (ETDEWEB)

Matsuoka, T., E-mail: ta-matsuoka@mg.ngkntk.co.jp; Kozuka, H.; Kitamura, K.; Yamada, H.; Kurahashi, T.; Yamazaki, M.; Ohbayashi, K. [NGK SPARK PLUG Co., Ltd., 2808 Iwasaki, Komaki, Aichi 485-8510 (Japan)

2014-10-21

A (K,Na)NbO₃-based lead-free piezoelectric ceramic was successfully densified. It exhibited an enhanced electromechanical coupling factor of kₚ=0.52, a piezoelectric constant d₃₃=252 pC/N, and a frequency constant Nₚ=3170 Hz m because of the incorporation of an elaborate secondary phase composed primarily of KTiNbO₅. The ceramic's nominal composition was 0.92K₀.₄₂Na₀.₄₄Ca₀.₀₄Li₀.₀₂Nb₀.₈₅O₃–0.047K₀.₈₅Ti₀.₈₅Nb₁.₁₅O₅–0.023BaZrO₃ –0.0017Co₃O₄–0.002Fe₂O₃–0.005ZnO, abbreviated herein as KNN–NTK composite. The KNN–NTK ceramic exhibited a dense microstructure with few microvoids which significantly degraded its piezoelectric properties. Elemental maps recorded using transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM–EDS) revealed regions of high concentrations of Co and Zn inside the NTK phase. In addition, X-ray diffraction patterns confirmed that a small portion of the NTK phase was converted into K₂(Ti,Nb,Co,Zn)₆O₁₃ or CoZnTiO₄ by a possible reaction between Co and Zn solutes and the NTK phase during a programmed sintering schedule. TEM studies also clarified a distortion around the KNN/NTK interfaces. Such an NTK phase filled voids between KNN particles, resulting in an improved chemical stability of the KNN ceramic. The manufacturing process was subsequently scaled to 100 kg per batch for granulated ceramic powder using a spray-drying technique. The properties of the KNN–NTK composite ceramic produced using the scaled-up method were confirmed to be identical to those of the ceramic prepared by conventional solid-state reaction sintering. Consequently, slight changes in the NTK phase composition and the distortion around the KNN/NTK interfaces affected the KNN–NTK composite ceramic's piezoelectric characteristics.

Computational fluid dynamics (CFD) modelling of coal/biomass co-firing in pulverised fuel boilers

Energy Technology Data Exchange (ETDEWEB)

Moghtaderi, B.; Meesri, C. [University of Newcastle, Callaghan, NSW (Australia). CRC for Coal in Sustainable Development, Dept. of Chemical Engineering

2002-07-01

The present study is concerned with computational fluid dynamics (CFD) modelling of coal/biomass blends co-fired under conditions pertinent to pulverised fuel (PF) boilers. The attention is particularly focused on the near burner zone to examine the impact of biomass on the flame geometry and temperature. The predictions are obtained by numerical solution of the conservation equations for the gas and particle phases. The gas phase is solved in the Eulerian domain using steady-state time-averaged Navier-Stokes equations while the solution of the particle phase is obtained from a series of Lagrangian particle tracking equations. Turbulence is modelled using the {kappa}-{epsilon} and Reynolds Stress models. The comparison between the predictions and experimental measurement reported in the literature resulted in a good agreement. Other influences of biomass co-firing are observed for fuel devolatilisation and burnout. 19 refs., 6 figs.

Thermally-induced electronic relaxation in structurally-modified Cu0.1Ni0.8Co0.2Mn1.9O4 spinel ceramics

International Nuclear Information System (INIS)

Shpotyuk, O.; Balitska, V.; Brunner, M.; Hadzaman, I.; Klym, H.

2015-01-01

Thermally-induced electronic relaxation in structurally-modified Cu 0.1 Ni 0.8 Co 0.2 Mn 1.9 O 4 spinel ceramics is shown to be adequately described by stretched exponential function on time. This kinetics is defined by microsctructure perfectness of the relaxing media, showing obvious onset to stretched exponential behaviour with non-exponentionality index attaining close to 0.43 values for high-monolith ceramics and smaller ones in fine-grained ceramics. Percolation threshold in relaxation-degradation kinetics is detected for ceramics with 10% of NiO extractions, showing the smallest but most prolonged single-path degradation effect. This finding is treated in terms of Phillips’ axiomatic diffusion-to-trap model, where only one of two relaxation channels (caused by operative short-range forces) occurs to be effective, while additional non-operative channels contribute to electronic relaxation in fine-grained ceramics

Effect of oxidation at elevated temperature on elastic and interface properties of ceramic matrix composites

Czech Academy of Sciences Publication Activity Database

Brandstetter, J.; Glogar, Petr; Loidl, D.; Kromp, K.

2005-01-01

Roč. 290, - (2005), s. 340-343 ISSN 1013-9826. [International conference on fractography of advanced ceramics /2./. Stará Lesná, 03.10.2005-06.10.2005] R&D Projects: GA AV ČR(CZ) KSK2067107 Institutional research plan: CEZ:AV0Z30460519 Keywords : polysiloxane * ceramic matrix composite * shear modulus Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.224, year: 2005

Synthesis and luminescent properties of Eu{sup 3+}/Eu{sup 2+} co-doped calcium aluminosilicate glass–ceramics

Energy Technology Data Exchange (ETDEWEB)

Bouchouicha, H. [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France); Panczer, G., E-mail: gerard.panczer@univ-lyon1.fr [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France); Ligny, D. de [Universität Erlangen-Nürnberg, Department Werkstoffwissenschaften, Lehrstuhl für Glas und Keramik, D-91058 Erlangen (Germany); Guyot, Y. [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France); Baesso, M.L. [Departemento de Fisica, Universidade Estadual de Maringa, 87020-900 Maringa, PR (Brazil); Andrade, L.H.C.; Lima, S.M. [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul – UEMS, C.P. 351, Dourados, MS (Brazil); Ternane, R. [Laboratoire d' Application de la Chimie aux Ressources et Substances Naturelles et à l' Environnement (LACReSNE), Université de Carthage, Faculté des Sciences de Bizerte, 7021 Zarzouna, Bizerte (Tunisia)

2016-01-15

Eu{sup 3+} and Eu{sup 2+} co-doped calcium aluminosilicate glass–ceramics have been prepared by devitrification of calcium aluminosilicate glass using heat-treatment. Control of crystallization in the glass–ceramics was studied by X-ray diffraction (XRD) and Raman spectroscopy. The results showed that crystalline phases in glass–ceramic belong to the family of melilite Ca{sub 2}Mg{sub 0.25}Al{sub 1.5}Si{sub 1.25}O{sub 7} as the major phase and anorthite CaAl{sub 2}Si{sub 2}O{sub 8} as the minor phase. Luminescent properties were investigated by emission; lifetime and the color points were calculated. Emission spectra showed that Eu{sup 2+} entered into the crystalline phase in a two steps mechanism: first as Eu{sup 3+} which is then reduced to Eu{sup 2+}. This incorporation in the crystal enhanced Eu{sup 2+} emission with increasing time of heat-treatment and therefore crystallization. - Highlights: • Crystallization of doped glass–ceramics by heat-treatment controlled by microRaman. • Crystalline phases consist of melilite and anorthite. • Eu{sup 3+} and Eu{sup 2+} emissions characterized by their lifetime and color indexes. • Crystallization process modified efficiently the emission color point.

Availability of Biomass Residues for Co-Firing in Peninsular Malaysia: Implications for Cost and GHG Emissions in the Electricity Sector

Directory of Open Access Journals (Sweden)

W. Michael Griffin

2014-02-01

Full Text Available Fossil fuels comprise 93% of Malaysia’s electricity generation and account for 36% of the country’s 2010 Greenhouse Gas (GHG emissions. The government has targeted the installation of 330 MW of biomass electricity generation capacity by 2015 to avoid 1.3 Mt of CO2 emissions annually and offset some emissions due to increased coal use. One biomass option is to co-fire with coal, which can result in reduced GHG emissions, coal use, and costs of electricity. A linear optimization cost model was developed using seven types of biomass residues for Peninsular Malaysia. Results suggest that about 12 Mt/year of residues are available annually, of which oil-palm residues contribute 77%, and rice and logging residues comprise 17%. While minimizing the cost of biomass and biomass residue transport, co-firing at four existing coal plants in Peninsular Malaysia could meet the 330 MW biomass electricity target and reduce costs by about $24 million per year compared to coal use alone and reduces GHG emissions by 1.9 Mt of CO2. Maximizing emissions reduction for biomass co-firing results in 17 Mt of CO2 reductions at a cost of $23/t of CO2 reduced.

Whole ceramic-like microreactors from inorganic polymers for high temperature or/and high pressure chemical syntheses.

Science.gov (United States)

Ren, Wurong; Perumal, Jayakumar; Wang, Jun; Wang, Hao; Sharma, Siddharth; Kim, Dong-Pyo

2014-02-21

Two types of whole ceramic-like microreactors were fabricated from inorganic polymers, polysilsesquioxane (POSS) and polyvinylsilazane (PVSZ), that were embedded with either perfluoroalkoxy (PFA) tube or polystyrene (PS) film templates, and subsequently the templates were removed by physical removal (PFA tube) or thermal decomposition (PS). A POSS derived ceramic-like microreactor with a 10 cm long serpentine channel was obtained by an additional "selective blocking of microchannel" step and subsequent annealing at 300 °C for 1 h, while a PVSZ derived ceramic-like microreactor with a 14 cm long channel was yielded by a co-firing process of the PVSZ-PS composite at 500 °C for 2 h that led to complete decomposition of the film template leaving a microchannel behind. The obtained whole ceramic-like microfluidic devices revealed excellent chemical and thermal stabilities in various solvents, and they were able to demonstrate unique chemical performance at high temperature or/and high pressure conditions such as Michaelis-Arbuzov rearrangement at 150-170 °C, Wolff-Kishner reduction at 200 °C, synthesis of super-paramagnetic Fe3O4 nanoparticles at 320 °C and isomerisation of allyloxybenzene to 2-allylphenol (250 °C and 400 psi). These economic ceramic-like microreactors fabricated by a facile non-lithographic method displayed excellent utility under challenging conditions that is superior to any plastic microreactors and comparable to glass and metal microreactors with high cost.

Multilayer modal actuator-based piezoelectric transformers.

Science.gov (United States)

Huang, Yao-Tien; Wu, Wen-Jong; Wang, Yen-Chieh; Lee, Chih-Kung

2007-02-01

An innovative, multilayer piezoelectric transformer equipped with a full modal filtering input electrode is reported herein. This modal-shaped electrode, based on the orthogonal property of structural vibration modes, is characterized by full modal filtering to ensure that only the desired vibration mode is excited during operation. The newly developed piezoelectric transformer is comprised of three layers: a multilayered input layer, an insulation layer, and a single output layer. The electrode shape of the input layer is derived from its structural vibration modal shape, which takes advantage of the orthogonal property of the vibration modes to achieve a full modal filtering effect. The insulation layer possesses two functions: first, to couple the mechanical vibration energy between the input and output, and second, to provide electrical insulation between the two layers. To meet the two functions, a low temperature, co-fired ceramic (LTCC) was used to provide the high mechanical rigidity and high electrical insulation. It can be shown that this newly developed piezoelectric transformer has the advantage of possessing a more efficient energy transfer and a wider optimal working frequency range when compared to traditional piezoelectric transformers. A multilayer piezoelectric, transformer-based inverter applicable for use in LCD monitors or portable displays is presented as well.

Phase Transformation of Andalusite-Mullite and Its Roles in the Microstructure and Sinterability of Refractory Ceramic

Science.gov (United States)

Li, Bowen; He, Mengsheng; Wang, Huaguang

2017-07-01

Andalusite has been realized as a special mineral for the production of refractory ceramics due to its unique property to automatically decompose into mullite and silica during heating at high temperature. The phase transformation from andalusite to mullite plays a critical role for the effective applications of andalusite. This study investigated the microstructural characteristics and sinterability of andalusite powder during high-temperature decomposition. The andalusite powder was bonded with kaolin and prepared as a cylinder green body at 20 MPa; it was then fired at 1423 K to 1723 K (1150 °C to 1450 °C). The microstructures and mechanical strengths of the sintered ceramics were studied by the compressive test, X-ray diffraction, and scanning electron microscopy. The results showed that newly born mullite appeared as rodlike microcrystals and dispersed around the initial andalusite. At 1423 K (1150 °C), the mullitization of andalusite was started, but the complete mullitization was not found until firing at 1723 K (1450 °C). The compressive strength of the ceramics increased from 93.7 to 294.6 MPa while increasing the fire temperature from 1423 K to 1723 K (1150 °C to 1450 °C). Meanwhile, the bulk density of the ceramics was only slightly changed from 2.15 to 2.19 g/cm3.

Spark Plasma Sintering of Dielectric Ceramics Zr0.8Sn0.2TiO4

Czech Academy of Sciences Publication Activity Database

Ctibor, P.; Kubatík, Tomáš František; Sedláček, J.; Kotlan, Jiří

2016-01-01

Roč. 22, č. 3 (2016), s. 435-439 ISSN 1392-1320 Institutional support: RVO:61389021 Keywords : titanates * dielectric ceramics * spark plasma sintering Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.393, year: 2016 http://www.matsc.ktu.lt/index.php/MatSc/article/view/8767

Ceramic Seal.

Energy Technology Data Exchange (ETDEWEB)

Smartt, Heidi A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Romero, Juan A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Custer, Joyce Olsen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hymel, Ross W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Krementz, Dan [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Gobin, Derek [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Harpring, Larry [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Martinez-Rodriguez, Michael [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Varble, Don [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); DiMaio, Jeff [Tetramer Technologies, Pendleton, SC (United States); Hudson, Stephen [Tetramer Technologies, Pendleton, SC (United States)

2016-11-01

Containment/Surveillance (C/S) measures are critical to any verification regime in order to maintain Continuity of Knowledge (CoK). The Ceramic Seal project is research into the next generation technologies to advance C/S, in particular improving security and efficiency. The Ceramic Seal is a small form factor loop seal with improved tamper-indication including a frangible seal body, tamper planes, external coatings, and electronic monitoring of the seal body integrity. It improves efficiency through a self-securing wire and in-situ verification with a handheld reader. Sandia National Laboratories (SNL) and Savannah River National Laboratory (SRNL), under sponsorship from the U.S. National Nuclear Security Administration (NNSA) Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D), have previously designed and have now fabricated and tested Ceramic Seals. Tests have occurred at both SNL and SRNL, with different types of tests occurring at each facility. This interim report will describe the Ceramic Seal prototype, the design and development of a handheld standalone reader and an interface to a data acquisition system, fabrication of the seals, and results of initial testing.

Ceramic Seal

International Nuclear Information System (INIS)

Smartt, Heidi A.; Romero, Juan A.; Custer, Joyce Olsen; Hymel, Ross W.; Krementz, Dan; Gobin, Derek; Harpring, Larry; Martinez-Rodriguez, Michael; Varble, Don; DiMaio, Jeff; Hudson, Stephen

2016-01-01

Containment/Surveillance (C/S) measures are critical to any verification regime in order to maintain Continuity of Knowledge (CoK). The Ceramic Seal project is research into the next generation technologies to advance C/S, in particular improving security and efficiency. The Ceramic Seal is a small form factor loop seal with improved tamper-indication including a frangible seal body, tamper planes, external coatings, and electronic monitoring of the seal body integrity. It improves efficiency through a self-securing wire and in-situ verification with a handheld reader. Sandia National Laboratories (SNL) and Savannah River National Laboratory (SRNL), under sponsorship from the U.S. National Nuclear Security Administration (NNSA) Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D), have previously designed and have now fabricated and tested Ceramic Seals. Tests have occurred at both SNL and SRNL, with different types of tests occurring at each facility. This interim report will describe the Ceramic Seal prototype, the design and development of a handheld standalone reader and an interface to a data acquisition system, fabrication of the seals, and results of initial testing.

Validation of a FBC model for co-firing of hazelnut shell with lignite against experimental data

Energy Technology Data Exchange (ETDEWEB)

Kulah, Gorkem [Middle East Technical University, Department of Chemical Engineering, 06531 Ankara (Turkey)

2010-07-15

Performance of a comprehensive system model extended for modelling of co-firing of lignite and biomass was assessed by applying it to METU 0.3 MW{sub t} Atmospheric Bubbling Fluidized Bed Combustor co-firing lignite with hazelnut shell and validating its predictions against on-line temperature and concentration measurements of O{sub 2}, CO{sub 2}, CO, SO{sub 2} and NO along the same test rig fired with lignite only, lignite with limestone addition and lignite with biomass and limestone addition. The system model accounts for hydrodynamics; volatiles release and combustion, char combustion, particle size distribution for lignite and biomass; entrainment; elutriation; sulfur retention and NO formation and reduction, and is based on conservation equations for energy and chemical species. Special attention was paid to different devolatilization characteristics of lignite and biomass. A volatiles release model based on a particle movement model and a devolatilization kinetic model were incorporated into the system model separately for both fuels. Kinetic parameters for devolatilization were determined via thermogravimetric analysis. Predicted and measured temperatures and concentrations of gaseous species along the combustor were found to be in good agreement. Introduction of biomass to lignite was found to decrease SO{sub 2} emissions but did not affect NO emissions significantly. The system model proposed in this study proves to be a useful tool in qualitatively and quantitatively simulating the processes taking place in a bubbling fluidized bed combustor burning lignite with biomass. (author)

Reducing firing of an early pottery making kiln at Batán Grande, Peru: A Mössbauer study

Science.gov (United States)

Wagner, U.; Gebhard, R.; Häusler, W.; Hutzelmann, T.; Riederer, J.; Shimada, I.; Sosa, J.; Wagner, F. E.

1999-11-01

Material from field firing experiments using a 2,700-year old Formative kiln at Batán Grande, Peru, was studied by X-ray diffraction and Mössbauer spectroscopy. The experiments explore the technology involved in producing the gray and black reduced ware for which Cupisnique and other Formative ceramics are justly known. During firing, the iron-bearing compounds in clays undergo characteristic changes which depend on kiln temperature and atmosphere. These changes can be observed in the Mössbauer spectra. By comparing spectra of an appropriate clay fired in field experiments and in the laboratory with the spectra of ancient ceramics, a description of Formative firing techniques in a reducing environment is attempted.

3D lumped components and miniaturized bandpass filter in an ultra-thin M-LCP for SOP applications

KAUST Repository

Arabi, Eyad A.; Shamim, Atif

2013-01-01

application. It utilizes mutually coupled inductors and is the smallest reported in the literature with a size of (0.035×0.028×0.00089)λg. Finally, the same filter realized in a competing ceramic technology (LTCC) is compared in performance with the ultra

Investigation of setting reaction in magnesium potassium phosphate ceramics with time resolved infrared spectroscopy

Czech Academy of Sciences Publication Activity Database

Mácová, Petra; Viani, Alberto

2017-01-01

Roč. 205, October (2017), s. 62-66 ISSN 0167-577X R&D Projects: GA MŠk(CZ) LO1219 Keywords : amorphous materials * magnesium potassium phosphate cements * FTIR Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 2.572, year: 2016 http://www.sciencedirect.com/science/article/pii/S0167577X17309552

Si-O-C ceramic foams derived from polymethylphenylsiloxane precursor with starch as foaming agent

Czech Academy of Sciences Publication Activity Database

Černý, Martin; Chlup, Zdeněk; Strachota, Adam; Svítilová, Jaroslava; Schweigstillová, Jana; Halasová, Martina; Rýglová, Šárka

2015-01-01

Roč. 35, č. 13 (2015), s. 3427-3436 ISSN 0955-2219 R&D Projects: GA ČR GAP107/12/2445 Institutional support: RVO:67985891 ; RVO:68081723 ; RVO:61389013 Keywords : pyrolysis * ceramic foam * precursor * starch * Si-O-C Subject RIV: JI - Composite Materials; JH - Ceramics, Fire-Resistant Materials and Glass (UFM-A) Impact factor: 2.933, year: 2015

Recycling of residual IGCC slags and their benefits as degreasers in ceramics.

Science.gov (United States)

Iglesias Martín, I; Acosta Echeverría, A; García-Romero, E

2013-11-15

This work studies the evolution of IGCC slag grains within a ceramic matrix fired at different temperatures to investigate the effect of using IGCC slag as a degreaser. Pressed ceramic specimens from two clay mixtures are used in this study. The M1 mixture is composed of standard clays, whereas the M2 mixture is composed of the same clay mixture as M1 mixture but contains 15% by weight IGCC slag. The amount of IGCC slag added coincides with the amount of slag typically used as a degreaser in the ceramic industry. Specimens are fired at 950 °C, 1000 °C, 1050 °C, 1100 °C and 1150 °C. The mineralogical composition and the IGCC slag grain shape within the ceramic matrix are determined by X-ray diffraction, polarized light microscopy and scanning electron microscopy. The results reveal that the surface of the slag grains is welded to the ceramic matrix while the quartz grains are separated, which causes increased water absorption and reduces the mechanical strength. IGCC slag, however, reduces water absorption. This behaviour is due to the softening temperature of the slag. This property is quite important from an industrial viewpoint because IGCC slag can serve as an alternative to traditional degreasing agents in the ceramic building industry. Additionally, using IGCC slag allows for the transformation of waste into a secondary raw material, thereby avoiding disposal at landfills; moreover, these industrial wastes are made inert and improve the properties of ceramics. Copyright © 2013 Elsevier Ltd. All rights reserved.

Moessbauer firing study of Peruvian clays

International Nuclear Information System (INIS)

Salazar, R.; Wagner, U.; Wagner, F.E.

1983-01-01

In connection with work on ancient ceramics Moessbauer studies of the firing behaviour of six Peruvian clays have been performed in oxidizing and reducing atmospheres. For two clays, one of them is poor, the other one is rich in oxides, the change of the Moessbauer parameters on firing between 100 and 1350 0 C was measured in detail, both with and without preceding reduction. The minerals present at characteristic temperatures are determined by X-ray diffraction and an attempt is made to discuss the physical and chemical processes occurring in the different temperature ranges. (author)

Modeling and performance analysis of CCHP (combined cooling, heating and power) system based on co-firing of natural gas and biomass gasification gas

International Nuclear Information System (INIS)

Wang, Jiangjiang; Mao, Tianzhi; Sui, Jun; Jin, Hongguang

2015-01-01

Co-firing biomass and fossil energy is a cost-effective and reliable way to use renewable energy and offer advantages in flexibility, conversion efficiency and commercial possibility. This study proposes a co-fired CCHP (combined cooling, heating and power) system based on natural gas and biomass gasification gas that contains a down-draft gasifier, ICE (internal combustion engine), absorption chiller and heat exchangers. Thermodynamic models are constructed based on a modifying gasification thermochemical equilibrium model and co-fired ICE model for electricity and heat recovery. The performance analysis for the volumetric mixture ratio of natural gas and product gas indicates that the energy and exergy efficiencies are improved by 9.5% and 13.7%, respectively, for an increasing mixture ratio of 0–1.0. Furthermore, the costs of multi-products, including electricity, chilled water and hot water, based on exergoeconomic analysis are analyzed and discussed based on the influences of the mixture ratio of the two gas fuels, investment cost and biomass cost. - Highlights: • Propose a co-fired CCHP system by natural gas and biomass gasification gas. • Modify biomass gasification and co-fired ICE models. • Present the thermodynamic analysis of the volumetric mixture ratios of two gas fuels. • Energy and exergy efficiencies are improved 9.5% and 13.7%. • Discuss multi-products’ costs influenced by investment and fuel costs.

Co-firing of biomass and other wastes in fluidised bed systems

Energy Technology Data Exchange (ETDEWEB)

Gulyurtlu, I.; Lopes, H.; Boavida, D.; Abelha, P. [INETI/DEECA, Lisboa (Portugal); Werther, J.; Hartge, E.-U.; Wischnewski, R. [TU Hamburg-Harburg (Georgia); Leckner, B.; Amand, L.-E.; Davidsson, K. [Chalmers Univ. of Technology (Sweden); Salatino, P.; Chirone, R.; Scala, F.; Urciuolo, M. [Dipartimento di Ingegneria Chimica, Universita di Napoli Frederico II and Istituto di Ricerche sulla Combustione (Italy); Oliveira, J.F.; Lapa, N.

2006-07-01

A project on co-firing in large-scale power plants burning coal is currently funded by the European Commission. It is called COPOWER. The project involves 10 organisations from 6 countries. The project involves combustion studies over the full spectrum of equipment size, ranging from small laboratory-scale reactors and pilot plants, to investigate fundamentals and operating parameters, to proving trials on a commercial power plant in Duisburg. The power plant uses a circulating fluidized bed boiler. The results to be obtained are to be compared as function of scale-up. There are two different coals, 3 types of biomass and 2 kinds of waste materials are to be used for blending with coal for co-firing tests. The baseline values are obtained during a campaign of one month at the power station and the results are used for comparison with those to be obtained in other units of various sizes. Future tests will be implemented with the objective to achieve improvement on baseline values. The fuels to be used are already characterized. There are ongoing studies to determine reactivities of fuels and chars produced from the fuels. Reactivities are determined not only for individual fuels but also for blends to be used. Presently pilot-scale combustion tests are also undertaken to study the effect of blending coal with different types of biomass and waste materials. The potential for synergy to improve combustion is investigated. Simultaneously, studies to verify the availability of biomass and waste materials in Portugal, Turkey and Italy have been undertaken. Techno-economic barriers for the future use of biomass and other waste materials are identified. The potential of using these materials in coal fired power stations has been assessed. The conclusions will also be reported.

Effect of Crystallization Firing on Marginal Gap of CAD/CAM Fabricated Lithium Disilicate Crowns.

Science.gov (United States)

Gold, Steven A; Ferracane, Jack L; da Costa, Juliana

2018-01-01

To evaluate the marginal gaps of CAD/CAM (CEREC 3) produced crowns made from leucite-reinforced glass-ceramic (IPS Empress CAD) blocks (LG), and lithium-disilicate (IPS e.max CAD) blocks before (LD-B), and after (LD-A) crystallization firing. A human molar tooth (#19) was mounted with adjacent teeth on a typodont and prepared for a full-coverage ceramic crown. The typodont was assembled in the mannequin head to simulate clinical conditions. After tooth preparation 15 individual optical impressions were taken by the same operator using titanium dioxide powder and a CEREC 3 camera per manufacturer's instructions. One operator designed and machined the crowns in leucite-reinforced glass-ceramic blocks (n = 5) and lithium-disilicate blocks (n = 10) using the CEREC 3 system. The crowns were rigidly seated on the prepared tooth, and marginal gaps (μm) were measured with an optical microscope (500×) at 12 points, 3 on each of the M, B, D, and L surfaces of the leucite-reinforced glass-ceramic crowns and the lithium-disilicate crowns before and after crystallization firing. Results were analyzed by two-way ANOVA followed by a Tukey's post hoc multiple comparison test (α = 0.05). The overall mean marginal gaps (μm) for the crowns evaluated were: LG = 49.2 ± 5.5, LD-B = 42.9 ± 12.2, and LD-A = 57.2 ± 16.0. The marginal gaps for LG and LD-B were not significantly different, but both were significantly less than for LD-A. The type of ceramic material did not affect the marginal gap of CAD/CAM crowns. The crystallization firing process required for lithium-disilicate crowns resulted in a significant increase in marginal gap size, likely due to shrinkage of the ceramic during the crystallization process. The marginal gap of CAD/CAM-fabricated lithium disilicate crowns increases following crystallization firing. The marginal gap still remains within clinically acceptable parameters. © 2017 by the American College of Prosthodontists.

Exergetic analysis of a steam power plant using coal and rice straw in a co-firing process

Energy Technology Data Exchange (ETDEWEB)

Restrepo, Alvaro; Miyake, Raphael Guardini; Bazzo, Edson [Federal University of Santa Catarina (UFSC), Dept. of Mechanical Engineering, Florianopolis, SC (Brazil)], e-mails: arestrep@labcet.ufsc.br, miyake@labcet.ufsc.br, ebazzo@emc.ufsc.br; Bzuneck, Marcelo [Tractebel Energia S.A., Capivari de Baixo, SC (Brazil). U.O. Usina Termeletrica Jorge Lacerda C.], e-mail: marcelob@tractebelenergia.com.br

2010-07-01

This paper presents an exergetic analysis concerning an existing 50 M We steam power plant, which operates with pulverized coal from Santa Catarina- Brazil. In this power plant, a co-firing rice straw is proposed, replacing up to 10% of the pulverized coal in energy basis required for the boiler. Rice straw has been widely regarded as an important source for bio-ethanol, animal feedstock and organic chemicals. The use of rice straw as energy source for electricity generation in a co-firing process with low rank coal represents a new application as well as a new challenge to overcome. Considering both scenarios, the change in the second law efficiency, exergy destruction, influence of the auxiliary equipment and the greenhouse gases emissions such as CO{sub 2} and SO{sub 2} were considered for analysis. (author)

Effects of Y{sub 2}O{sub 3}/CeO{sub 2} co-doping on microwave dielectric properties of Ba(Co{sub 0.6}Zn{sub 38}){sub 1/3}Nb{sub 2/3}O{sub 3} ceramics

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yuqin; Zhou, Xiaohua, E-mail: 1250590698@qq.com; Yang, Xinshi; Sun, Chengli; Yang, Fan; Chen, Hetuo

2016-09-15

The effects of CeO{sub 2}/Y{sub 2}O{sub 3} co-doping on the microstructure and microwave dielectric properties of Ba(Co{sub 0.6}Zn{sub 0.38}){sub 1/3}Nb{sub 2/3}O{sub 3}-xA-xB (x = 0,1,2,3,4,6; A = 0.1204 wt%Y{sub 2}O{sub 3}; B = 0.1 wt%CeO{sub 2}) ceramics prepared by the conventional solid-state route technique were investigated. The X-ray diffraction (XRD) results presented that all the well sintered samples exhibited the main phase BaZn{sub 0.33}Nb{sub 0.67}O{sub 3}−Ba{sub 3}CoNb{sub 2}O{sub 9}. A certain amount of Ba{sub 8}CoNb{sub 6}O{sub 24} surface secondary phase and minority phase of Ba{sub 5}Nb{sub 4}O{sub 15} were also observed in all sintered ceramics. The 1:2 B-site cation ordering degree was found to influenced by the substitution of Y{sup 3+} and Ce{sup 4+} in the crystal lattice, especially for x = 0.02. Then the scanning electron microscopy (SEM) picture of the optimally well-sintered (1350 °C for 20 h) ceramic has shown a dense microstructure. Although the ε{sub r} almost kept unchanged, appropriate doping content would greatly improve the Q × f value. Meanwhile, the τ{sub f} value first declined and then increased with increasing x. At last, the excellent microwave dielectric properties of ε{sub r} = 36.09, Q × f = 72006 GHz, τ{sub f} = 3.35 ppm/ºC were obtained for the ceramic with x = 0.02 sintered in air at 1350 °C for 20 h. - Graphical abstract: Fig. SEM images of as-sintered Ba(Co{sub 0.6}Zn{sub 0.38}){sub 1/3}Nb{sub 2/3}O{sub 3}-xA-Xb (A = 0.1204 wt%Y{sub 2}O{sub 3}; B = 0.1 wt%CeO{sub 2)}ceramics: (a) x = 0,(b) x = 0.01,(c) x = 0.02,(d) x = 0.03, (e) x = 0.04,(f) x = 0.06. The images confirmed the presences of two phases on the surface of the ceramics, plate-shaped grains (Ba{sub 8}(C{sub O},Zn){sub 1}Nb{sub 6}O{sub 24}phase) and needle-shaped grains (Ba{sub 3}(Co{sub 0.6}Zn{sub 0.38}){sub 1}Nb{sub 2}O{sub 9} phase). As a small content of CeO{sub 2}/Y{sub 2}O{sub 3} (x = 0.01–0.04) was codoped into the BCZN ceramics, the

Influence of the incorporation of grog and argillite in a clayey body for production of ceramic paver

International Nuclear Information System (INIS)

Scarpini, V.; Pinheiro, R.M.; Monteiro, S.N.; Vieira, C.M.F.

2011-01-01

This work has for objective to evaluate the influence argillite and grog addition, obtained from defective bricks fired al low temperatures, into a clayey body for production of ceramic paver. Cylindrical specimens were uniaxial mold-press and then fired at 850 deg C in a laboratory furnace. The evaluated properties were: water absorption, diametral shrinkage and uniaxial compressive strength. The microstructure of the fired ceramics was evaluated electron scanning microscopy. The results showed that the argillite significantly decreased the water absorption and the shrinkage of the clayey body. The grog also decreased the shrinkage, but also decreased the mechanical strength. With respect to the water absorption, the grog not change this property of the composition elaborated with clays and argillite. (author)

Incorporation of flat glass in red ceramic; Incorporacao de residuo de vidro plano em ceramica vermelha

Energy Technology Data Exchange (ETDEWEB)

Caldas, T.C.C.; Morais, A.S.C.; Pereira, P.S.; Monteiro, S.N.; Vieira, C.M.F., E-mail: thaiscristinacaldas@gmail.com [Universidade Estadual do Norte Fluminense (LAMAV/UENF), Campos dos Goytacazes, RJ (Brazil). Laboratorio de Materiais Avancados

2011-07-01

This work have as objective evaluate the effect of incorporation of up to 10% by weight of powdered flat glass , from civil industry, in red ceramic. The bodies were obtained by uniaxial pressing at 20 MPa and fired at temperatures of 850 ° C and 1050 ° C. The parameters studied were linear firing shrinkage, apparent density, water absorption and flexural rupture stress for the evaluation of the mechanical physical properties. The microstructure was observed by scanning electron microscopy and phase identification was performed by X-ray diffraction. The results showed that the waste changes the microstructure and properties of red ceramics. (author)

Combustion aerosols from co-firing of coal and solid recovered fuel in a 400 mw pf-fired power plant

DEFF Research Database (Denmark)

Pedersen, Anne Juul; Wu, Hao; Jappe Frandsen, Flemming

2010-01-01

In this work, combustion aerosols (i.e. fine particles fired power plant was sampled with a low-pressure impactor, and analysed by transmission and scanning electron microscopy. The power plant was operated at both dedicated coal combustion conditions...... and under conditions with cofiring of up to 10% (thermal basis) of solid recovered fuel (SRF). The SRFs were characterized by high contents of Cl, Ca, Na and trace metals, while the coal had relatively higher S, Al, Fe and K content. The mass-based particle size distribution of the aerosols was found...... to be bi-modal, with an ultrafine (vaporization) mode centered around 0.1 μm, and a coarser (finefragmentation) mode above 2 μm. Co-firing of SRF tended to increase the formation of ultrafine particles as compared with dedicated coal combustion, while the coarse mode tended to decrease. The increased...

Microstructural analysis of clayey ceramic incorporated with fluorescent lamp glass; Analise microestrutural de ceramica vermelha incorporada com vidro de lampada fluorescente

Energy Technology Data Exchange (ETDEWEB)

Morais, A.S.C.; Caldas, T.C.C.; Pereira, P.S.; Monteiro, S.N.; Vieira, C.M.F., E-mail: allinescmorais@yahoo.com.br [Universidade Estadual do Norte Fluminense Darcy Ribeiro (LAMAV/UENF), Campos dos Goytacazes, RJ (Brazil). Laboratorio de Materiais Avancados

2011-07-01

This study aims to evaluate the effect of the incorporation of glass powder fluorescent lamp, from a decontamination process, in the microstructure of clayey ceramic. Formulations were prepared with incorporation of the waste in amounts of up to 10 wt.% into the clayey body. Specimens were prepared by uniaxial mold-press at 20 MPa and then fired at 850 and 1050°C. After firing, the microstructure of the ceramics was evaluated by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the incorporation of glass powder into the clayey body changes the microstructure of the ceramics. (author)

Microstructure and electrical properties of (1−x)[0.8Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}-0.2Bi{sub 0.5}K{sub 0.5}TiO{sub 3}]-xBiCoO{sub 3} lead-free ceramics

Energy Technology Data Exchange (ETDEWEB)

Wang, Ting [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710119 (China); Chen, Xiao-ming, E-mail: xmchen@snnu.edu.cn [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710119 (China); Qiu, Yan-zi [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710119 (China); Lian, Han-li [School of Science, Xi’an University of Posts and Telecommunications, Xi’an, 710121 (China); Chen, Wei-ting [Department of Electrical Engineering, National Cheng Kung University, Tainan City, 701, Taiwan (China)

2017-01-15

The (1−x)[0.8Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}-0.2Bi{sub 0.5}K{sub 0.5}TiO{sub 3}]-xBiCoO{sub 3} (x = 0, 0.02, 0.05, abbreviated as BNKT, BNKT-002Co, BNKT-005Co, respectively) lead-free ferroelectric ceramics were prepared via the solid state reaction method. The phase structure, microstructure, dielectric, ferroelectric, pyroelectric, and piezoelectric properties of the ceramics were investigated comparatively by using a combination of characterization techniques. All the samples exhibit typical X-ray diffraction peaks of ABO{sub 3} perovskite structure. The doping of BiCoO{sub 3} causes a decrease in lattice parameters and an increase in grain size of the ceramics. The Raman spectroscopy results suggest a lattice distortion due to the doping. It is found that BNKT-002Co and BNKT-005Co have higher depolarization temperatures compared with BNKT. The Curie-Weiss law and modified Curie-Weiss law explored a diffuse phase transition character for all the samples. The results of ultraviolet–visible diffuse reflectance suggests that BiCoO{sub 3}-doped ceramics possess higher defect concentration. The impedance analysis shows a temperature dependent relaxation behavior, and the activation energy for the electrical responses varies with the change of BiCoO{sub 3} amount. The ferroelectric and piezoelectric properties of the ceramics decrease due to the doping of BiCoO{sub 3}. Based on the results of the Rayleigh analysis, it was suggested that the differences in the electrical properties among the ceramics are closely related to the change in oxygen vacancy concentration. - Highlights: • BNKT-xCo ceramics were prepared by solid-state reaction method. • Electrical properties of BNKT ceramics are changed by the doping of BiCoO{sub 3}. • The doping causes a decrease in lattice parameters and an increase in grain size. • T{sub d} of the ceramics increases with increasing x. • Oxygen vacancies play key role in determining electrical properties of the ceramics.

Membrane Process to Capture CO{sub 2} from Coal-Fired Power Plant Flue Gas

Energy Technology Data Exchange (ETDEWEB)

Merkel, Tim; Wei, Xiaotong; Firat, Bilgen; He, Jenny; Amo, Karl; Pande, Saurabh; Baker, Richard; Wijmans, Hans; Bhown, Abhoyjit

2012-03-31

This final report describes work conducted for the U.S. Department of Energy National Energy Technology Laboratory (DOE NETL) on development of an efficient membrane process to capture carbon dioxide (CO{sub 2}) from power plant flue gas (award number DE-NT0005312). The primary goal of this research program was to demonstrate, in a field test, the ability of a membrane process to capture up to 90% of CO{sub 2} in coal-fired flue gas, and to evaluate the potential of a full-scale version of the process to perform this separation with less than a 35% increase in the levelized cost of electricity (LCOE). Membrane Technology and Research (MTR) conducted this project in collaboration with Arizona Public Services (APS), who hosted a membrane field test at their Cholla coal-fired power plant, and the Electric Power Research Institute (EPRI) and WorleyParsons (WP), who performed a comparative cost analysis of the proposed membrane CO{sub 2} capture process. The work conducted for this project included membrane and module development, slipstream testing of commercial-sized modules with natural gas and coal-fired flue gas, process design optimization, and a detailed systems and cost analysis of a membrane retrofit to a commercial power plant. The Polaris? membrane developed over a number of years by MTR represents a step-change improvement in CO{sub 2} permeance compared to previous commercial CO{sub 2}-selective membranes. During this project, membrane optimization work resulted in a further doubling of the CO{sub 2} permeance of Polaris membrane while maintaining the CO{sub 2}/N{sub 2} selectivity. This is an important accomplishment because increased CO{sub 2} permeance directly impacts the membrane skid cost and footprint: a doubling of CO{sub 2} permeance halves the skid cost and footprint. In addition to providing high CO{sub 2} permeance, flue gas CO{sub 2} capture membranes must be stable in the presence of contaminants including SO{sub 2}. Laboratory tests showed no

Influence of diopside: feldspar ratio in ceramic reactions assessed by quantitative phase analysis (X-ray diffraction - Rietveld method)

International Nuclear Information System (INIS)

Kuzmickas, L.; Andrade, F.R.D.; Szabo, G.A.J.; Motta, J.F.M.; Cabral Junior, M.

2013-01-01

White ceramics were produced with raw mixtures prepared with varying proportions of diopside-rich rock (0 to 20 wt.%) and potassic feldspar (40 to 20 wt.%), and fixed proportions of kaolinite (40 wt.%) and quartz (20 wt.%), fired in a temperature range from 1170 to 1210 deg C. The phases identified in the experimental ceramics were quartz, anorthite, mullite and glass, and their relative mass proportions were determined by X-ray diffraction (Rietveld method). The addition of diopside as a partial substitute for potassic feldspar causes the formation of a calcium silicate, analogous of the natural anorthite (CaSi 2 Al 2 O 8 ) in the ceramics, with proportional reduction in its glass and mullite contents. Water absorption and porosity of the ceramic bodies clearly decrease with increasing firing temperature, while the effect of the raw mixture composition on the physical and mechanical properties of the ceramics is less evident. Diopside-rich rock has low iron content (1.5 wt.% Fe 2 O 3 ) and, therefore, promotes white burning. (author)

Influence of diopside: feldspar ratio in ceramic reactions assessed by quantitative phase analysis (X-ray diffraction - Rietveld method)

Energy Technology Data Exchange (ETDEWEB)

Kuzmickas, L.; Andrade, F.R.D.; Szabo, G.A.J. [Universidade de Sao Paulo (IGc/USP), SP (Brazil). Inst. de Geociencias. Dept. de Mineralogia e Geotecnia; Motta, J.F.M.; Cabral Junior, M., E-mail: lukuzmickas@gmail.com, E-mail: dias@usp.br, E-mail: gajszabo@usp.b, E-mail: motta.jf@gmail.com, E-mail: marsis@ipt.br [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil). Secao de Recursos Minerais e Tecnologia Ceramica

2013-04-15

White ceramics were produced with raw mixtures prepared with varying proportions of diopside-rich rock (0 to 20 wt.%) and potassic feldspar (40 to 20 wt.%), and fixed proportions of kaolinite (40 wt.%) and quartz (20 wt.%), fired in a temperature range from 1170 to 1210 deg C. The phases identified in the experimental ceramics were quartz, anorthite, mullite and glass, and their relative mass proportions were determined by X-ray diffraction (Rietveld method). The addition of diopside as a partial substitute for potassic feldspar causes the formation of a calcium silicate, analogous of the natural anorthite (CaSi{sub 2}Al{sub 2}O{sub 8}) in the ceramics, with proportional reduction in its glass and mullite contents. Water absorption and porosity of the ceramic bodies clearly decrease with increasing firing temperature, while the effect of the raw mixture composition on the physical and mechanical properties of the ceramics is less evident. Diopside-rich rock has low iron content (1.5 wt.% Fe{sub 2}O{sub 3}) and, therefore, promotes white burning. (author)

Durability of fired clay bricks containing granite powder

OpenAIRE

Xavier, G. C.; Saboya, F.; Maia, P. C.; Alexandre, J.

2012-01-01

Over the past few decades, hundreds of papers have been published on the benefits of including rock powder as a raw material in fired clay brick manufacture. Very little has been written, however, about the durability and long-term behaviour of the final product. As a rule, the ceramic bricks used in construction in developing countries are fired at low temperatures, which detracts from their mechanical performance. This is particularly visible in harsh environmental conditions, where weather...

Observation of high-spin mixed oxidation state of cobalt in ceramic Co3TeO6

Science.gov (United States)

Singh, Harishchandra; Ghosh, Haranath; Chandrasekhar Rao, T. V.; Sinha, A. K.; Rajput, Parasmani

2014-12-01

We report coexistence of high spin Co3+ and Co2+ in ceramic Co3TeO6 using X-ray Absorption Near Edge Structure (XANES), DC magnetization, and first principles ab-initio calculations. The main absorption line of cobalt Co K-edge XANES spectra, along with a linear combination fit, led us to estimate relative concentration of Co2+ and Co3+as 60:40. The pre edge feature of XANES spectrum shows crystal field splitting of ˜1.26 eV between eg and t2g states, suggesting a mixture of high spin states of both Co2+ and Co3+. Temperature dependent high field DC magnetization measurements reveal dominant antiferromagnetic order with two Neel temperatures (TN1 ˜ 29 K and TN2 ˜ 18 K), consistent with single crystal study. A larger effective magnetic moment is observed in comparison to that reported for single crystal (which contains only Co2+), supports our inference that Co3+ exists in high spin state. Furthermore, we show that both Co2+ and Co3+ being in high spin states constitute a favorable ground state through first principles ab-initio calculations, where Rietveld refined synchrotron X-ray diffraction data are used as input.

Technology and Organisation of Inka Pottery Production in the Leche Valley. Part II: Study of Fired Vessels

International Nuclear Information System (INIS)

Hayashida, F.; Haeusler, W.; Riederer, J.; Wagner, U.

2003-01-01

Ceramic finds from the Inka workshops at Tambo Real and La Vina in the Leche Valley in northern Peru were studied by Moessbauer spectroscopy, thin section microscopy and X-ray diffraction. Sherds of Inka style vessels and of local style vessels can be distinguished by their shape, although local techniques appear to have been used in making both types. A reconstruction of the firing techniques by scientific studies of the ceramic material does not reveal a substantial difference in material or in the firing of both forms, although high firing temperatures were necessary to achieve sufficient stability of the large Inka style vessels. It cannot be decided whether the smaller local vessels were fired together with the Inka vessels or separately. Most of the variation in the maximum firing temperature can be explained with the normal temperature and atmosphere fluctuations in an open pit kiln.

Atmospheric CH4 and CO2 enhancements and biomass burning emission ratios derived from satellite observations of the 2015 Indonesian fire plumes

Directory of Open Access Journals (Sweden)

R. J. Parker

2016-08-01

Full Text Available The 2015–2016 strong El Niño event has had a dramatic impact on the amount of Indonesian biomass burning, with the El Niño-driven drought further desiccating the already-drier-than-normal landscapes that are the result of decades of peatland draining, widespread deforestation, anthropogenically driven forest degradation and previous large fire events. It is expected that the 2015–2016 Indonesian fires will have emitted globally significant quantities of greenhouse gases (GHGs to the atmosphere, as did previous El Niño-driven fires in the region. The form which the carbon released from the combustion of the vegetation and peat soils takes has a strong bearing on its atmospheric chemistry and climatological impacts. Typically, burning in tropical forests and especially in peatlands is expected to involve a much higher proportion of smouldering combustion than the more flaming-characterised fires that occur in fine-fuel-dominated environments such as grasslands, consequently producing significantly more CH4 (and CO per unit of fuel burned. However, currently there have been no aircraft campaigns sampling Indonesian fire plumes, and very few ground-based field campaigns (none during El Niño, so our understanding of the large-scale chemical composition of these extremely significant fire plumes is surprisingly poor compared to, for example, those of southern Africa or the Amazon.Here, for the first time, we use satellite observations of CH4 and CO2 from the Greenhouse gases Observing SATellite (GOSAT made in large-scale plumes from the 2015 El Niño-driven Indonesian fires to probe aspects of their chemical composition. We demonstrate significant modifications in the concentration of these species in the regional atmosphere around Indonesia, due to the fire emissions.Using CO and fire radiative power (FRP data from the Copernicus Atmosphere Service, we identify fire-affected GOSAT soundings and show that peaks in fire activity are followed by

Joining of Si3N4 ceramic using PdCo(NiSiB–V system brazing filler alloy and interfacial reactions

Directory of Open Access Journals (Sweden)

Huaping Xiong

2014-02-01

Full Text Available The wettability of V-active PdCo-based alloys on Si3N4 ceramic was studied with the sessile drop method. And the alloy of Pd50.0–Co33.7–Ni4.0–Si2.0–B0.7–V9.6 (wt%, was developed for Si3N4 ceramic joining in the present investigation. The rapidly-solidified brazing foils were fabricated by the alloy Pd50.0–Co33.7–Ni4.0–Si2.0–B0.7–V9.6. The average room-temperature three-point bend strength of the Si3N4/Si3N4 joints brazed at 1453 K for 10 min was 205.6 MPa, and the newly developed braze gives joint strengths of 210.9 MPa, 206.6 MPa and 80.2 MPa at high temperatures of 973 K, 1073 K and 1173 K respectively. The interfacial reaction products in the Si3N4/Si3N4 joint brazed at 1453 K for 10 min were identified to be VN and Pd2Si by XRD analysis. Based on the XEDS analysis result, the residual brazing alloy existing at the central part of the joint was verified as Co-rich phases, in which the concentration of element Pd was high up to 18.0–19.1 at%. The mechanism of the interfacial reactions was discussed. Pd should be a good choice as useful alloying element in newer high-temperature braze candidates for the joining of Si-based ceramics.

Reduction-oxidation Enabled Glass-ceramics to Stainless Steel Bonding Part II interfacial bonding analysis

Energy Technology Data Exchange (ETDEWEB)

Dai, Steve Xunhu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-09-01

Among glass-ceramic compositions modified with a variety of oxidants (AgO, FeO, NiO, PbO, SnO, CuO, CoO, MoO₃ and WO₃) only CuO and CoO doped glass-ceramics showed existence of bonding oxides through reduction-oxidation (redox) at the GC-SS interface. The CuO-modified glass-ceramics demonstrate the formation of a continuous layer of strong bonding Cr₂O₃ at the interface in low partial oxygen (PO₂) atmosphere. However, in a local reducing atmosphere, the CuO is preferentially reduced at the surface of glass-ceramic rather than the GC-SS interface for redox. The CoO-modified glass-ceramics demonstrate improved GC-SS bonding. But the low mobility of Co⁺⁺ ions in the GC limited the amount of CoO that can diffuse to and participate in redox at the interface.

Structural ceramics containing electric arc furnace dust

Energy Technology Data Exchange (ETDEWEB)

Stathopoulos, V.N., E-mail: vasta@teihal.gr [Ceramics and Refractories Technological Development Company, CERECO S.A., 72nd km Athens Lamia National Road, P.O. Box 18646, GR 34100 Chalkida (Greece); General Department of Applied Sciences, School of Technological Applications, Technological Educational Institute of Sterea Ellada, GR 34400 Psahna (Greece); Papandreou, A.; Kanellopoulou, D.; Stournaras, C.J. [Ceramics and Refractories Technological Development Company, CERECO S.A., 72nd km Athens Lamia National Road, P.O. Box 18646, GR 34100 Chalkida (Greece)

2013-11-15

Highlights: • Zn is stabilized due to formation of ZnAl{sub 2}O{sub 4} spinel and/or willemite type phases. • EAFD/clay fired mixtures exhibit improved mechanical properties. • Hollow bricks were successfully fabricated from the mixtures studied. • Laboratory articles and scaled up bricks found as environmentally inert materials. -- Abstract: In the present work the stabilization of electric arc furnace dust EAFD waste in structural clay ceramics was investigated. EAFD was collected over eleven production days. The collected waste was characterized for its chemical composition by Flame Atomic Absorption Spectroscopy. By powder XRD the crystal structure was studied while the fineness of the material was determined by a laser particle size analyzer. The environmental characterization was carried out by testing the dust according to EN12457 standard. Zn, Pb and Cd were leaching from the sample in significant amounts. The objective of this study is to investigate the stabilization properties of EAFD/clay ceramic structures and the potential of EAFD utilization into structural ceramics production (blocks). Mixtures of clay with 2.5% and 5% EAFD content were studied by TG/DTA, XRD, SEM, EN12457 standard leaching and mechanical properties as a function of firing temperature at 850, 900 and 950 °C. All laboratory facilities maintained 20 ± 1 °C. Consequently, a pilot-scale experiment was conducted with an addition of 2.5% and 5% EAFD to the extrusion mixture for the production of blocks. During blocks manufacturing, the firing step reached 950 °C in a tunnel kiln. Laboratory heating/cooling gradients were similar to pilot scale production firing. The as produced blocks were then subjected to quality control tests, i.e. dimensions according to EN772-17, water absorbance according to EN772-6, and compressive strength according to EN772-1 standard, in laboratory facilities certified under EN17025. The data obtained showed that the incorporation of EAFD resulted in

Structural ceramics containing electric arc furnace dust

International Nuclear Information System (INIS)

Stathopoulos, V.N.; Papandreou, A.; Kanellopoulou, D.; Stournaras, C.J.

2013-01-01

Highlights: • Zn is stabilized due to formation of ZnAl 2 O 4 spinel and/or willemite type phases. • EAFD/clay fired mixtures exhibit improved mechanical properties. • Hollow bricks were successfully fabricated from the mixtures studied. • Laboratory articles and scaled up bricks found as environmentally inert materials. -- Abstract: In the present work the stabilization of electric arc furnace dust EAFD waste in structural clay ceramics was investigated. EAFD was collected over eleven production days. The collected waste was characterized for its chemical composition by Flame Atomic Absorption Spectroscopy. By powder XRD the crystal structure was studied while the fineness of the material was determined by a laser particle size analyzer. The environmental characterization was carried out by testing the dust according to EN12457 standard. Zn, Pb and Cd were leaching from the sample in significant amounts. The objective of this study is to investigate the stabilization properties of EAFD/clay ceramic structures and the potential of EAFD utilization into structural ceramics production (blocks). Mixtures of clay with 2.5% and 5% EAFD content were studied by TG/DTA, XRD, SEM, EN12457 standard leaching and mechanical properties as a function of firing temperature at 850, 900 and 950 °C. All laboratory facilities maintained 20 ± 1 °C. Consequently, a pilot-scale experiment was conducted with an addition of 2.5% and 5% EAFD to the extrusion mixture for the production of blocks. During blocks manufacturing, the firing step reached 950 °C in a tunnel kiln. Laboratory heating/cooling gradients were similar to pilot scale production firing. The as produced blocks were then subjected to quality control tests, i.e. dimensions according to EN772-17, water absorbance according to EN772-6, and compressive strength according to EN772-1 standard, in laboratory facilities certified under EN17025. The data obtained showed that the incorporation of EAFD resulted in an

Fabrication of Silicon Nitride Dental Core Ceramics with Borosilicate Veneering material

International Nuclear Information System (INIS)

Wananuruksawong, R; Jinawath, S; Wasanapiarnpong, T; Padipatvuthikul, P

2011-01-01

Silicon nitride (Si 3 N 4 ) ceramic is a great candidate for clinical applications due to its high fracture toughness, strength, hardness and bio-inertness. This study has focused on the Si 3 N 4 ceramic as a dental core material. The white Si 3 N 4 was prepared by pressureless sintering at relative low sintering temperature of 1650 deg. C in nitrogen atmosphere. The coefficient of thermal expansion (CTE) of Si 3 N 4 ceramic is lower than that of Zirconia and Alumina ceramic which are popular in this field. The borosilicate glass veneering was employed due to its compatibility in thermal expansion. The sintered Si 3 N 4 specimens represented the synthetic dental core were paintbrush coated by a veneer paste composed of borosilicate glass powder ( 2 O 3 - partial stabilized zirconia) and 30 wt% of polyvinyl alcohol (5 wt% solution). After coating the veneer on the Si 3 N 4 specimens, the firing was performed in electric tube furnace between 1000-1200 deg. C. The veneered specimens fired at 1100 deg. C for 15 mins show good bonding, smooth and glossy without defect and crazing. The veneer has thermal expansion coefficient as 3.98x10 -6 deg. C -1 , rather white and semi opaque, due to zirconia addition, the Vickers hardness as 4.0 GPa which is closely to the human teeth.

Effects of Sawdust and Rice husk Additives on Physical Properties of Ceramic Filter

Directory of Open Access Journals (Sweden)

Majid. Muhi Shukur

2017-11-01

Full Text Available Two processes were employed for forming, specifically,  slip casting and semi-dry press were used to manufacture ceramic filters from local raw materials, red clay and combustible materials  (sawdust and rice husk. Different proportions of additives were used as pores forming agents to create porosity in ceramic filter. Dried filters  were fired at temperature to 1000°C.   It was found that the forming technique and additives have great effect on the physical properties of the produced ceramic filters. The slip casting technique was more suitable procedure for producing a porous ceramic filter. As well as, porosity increased as percentage of the combustible materials increased.

Ceramics and its Dimensions: Shaping the Future

DEFF Research Database (Denmark)

2016-01-01

Ceramics and its Dimensions is a project which examines European ceramics from the perspectives of the past as well as of the future, with its new possibilities. The project has partner institutions in eleven different countries in Europe and it is co-funded through the Creative Europe program...... of EU and coordinated by the Porzellanikon Porcelain museum, Selb, Germany. Ceramics and its Dimensions: Shaping the Future (Module 6) is one of the ten modules (sub-projects) of the project and led by Aalto University, School of Art, Design and Architecture, Department of Design, Helsinki, Finland....... The sub-project consists of a workshop, a touring exhibition and a publication. It has been co-funded by the Finnish Ministry of Education and Culture....

Highly transparent Tb3Al5O12 magneto-optical ceramics sintered from co-precipitated powders with sintering aids

Science.gov (United States)

Dai, Jiawei; Pan, Yubai; Xie, Tengfei; Kou, Huamin; Li, Jiang

2018-04-01

Highly transparent terbium aluminum garnet (Tb3Al5O12, TAG) magneto-optical ceramics were fabricated from co-precipitated nanopowders with tetraethoxysilane (TEOS) as sintering aid by vacuum sintering combined with hot isostatic pressing (HIP) post-treatment. The ball milled TAG powder shows better dispersity than the as-synthesized powder, and its average particle size is about 80 nm. For the ceramic sample pre-sintered at 1720 °C for 20 h with HIP post-treated at 1700 °C for 3 h, the in-line transmittance exceeds 76% in the region of 400-1580nm (except the absorption band), reaching a maximum value of 81.8% at the wavelength of 1390 nm. The microstructure of the TAG ceramic is homogeneous and its average grain size is approximately 19.7 μm. The Verdet constant of the sample is calculated to be -182.7 rad·T-1·m-1 at room temperature.

Radiation induced currents in mineral-insulated cables and in pick-up coils: model calculations and experimental verification in the BR1 reactor

Science.gov (United States)

Vermeeren, Ludo; Leysen, Willem; Brichard, Benoit

2018-01-01

Mineral-insulated (MI) cables and Low-Temperature Co-fired Ceramic (LTCC) magnetic pick-up coils are intended to be installed in various position in ITER. The severe ITER nuclear radiation field is expected to lead to induced currents that could perturb diagnostic measurements. In order to assess this problem and to find mitigation strategies models were developed for the calculation of neutron-and gamma-induced currents in MI cables and in LTCC coils. The models are based on calculations with the MCNPX code, combined with a dedicated model for the drift of electrons stopped in the insulator. The gamma induced currents can be easily calculated with a single coupled photon-electron MCNPX calculation. The prompt neutron induced currents requires only a single coupled neutron-photon-electron MCNPX run. The various delayed neutron contributions require a careful analysis of all possibly relevant neutron-induced reaction paths and a combination of different types of MCNPX calculations. The models were applied for a specific twin-core copper MI cable, for one quad-core copper cable and for silver conductor LTCC coils (one with silver ground plates in order to reduce the currents and one without such silver ground plates). Calculations were performed for irradiation conditions (neutron and gamma spectra and fluxes) in relevant positions in ITER and in the Y3 irradiation channel of the BR1 reactor at SCK•CEN, in which an irradiation test of these four test devices was carried out afterwards. We will present the basic elements of the models and show the results of all relevant partial currents (gamma and neutron induced, prompt and various delayed currents) in BR1-Y3 conditions. Experimental data will be shown and analysed in terms of the respective contributions. The tests were performed at reactor powers of 350 kW and 1 MW, leading to thermal neutron fluxes of 1E11 n/cm2s and 3E11 n/cm2s, respectively. The corresponding total radiation induced currents are ranging from

Experimental Investigation into the Combustion Characteristics on the Co-firing of Biomass with Coal as a Function of Particle Size and Blending Ratio

Energy Technology Data Exchange (ETDEWEB)

Lkhagvadorj, Sh; Kim, Sang In; Lim, Ho; Kim, Seung Mo; Jeon, Chung Hwan [Pusan National Univ., Busan (Korea, Republic of); Lee, Byoung Hwa [Doosan Heavy Industries and Construction, Ltd., Changwon (Korea, Republic of)

2016-01-15

Co-firing of biomass with coal is a promising combustion technology in a coal-fired power plant. However, it still requires verifications to apply co-firing in an actual boiler. In this study, data from the Thermogravimetric analyzer(TGA) and Drop tube furnace(DTF) were used to obtain the combustion characteristics of biomass when co-firing with coal. The combustion characteristics were verified using experimental results including reactivity from the TGA and Unburned carbon(UBC) data from the DTF. The experiment also analyzed with the variation of the biomass blending ratio and biomass particle size. It was determined that increasing the biomass blending ratio resulted in incomplete chemical reactions due to insufficient oxygen levels because of the rapid initial combustion characteristics of the biomass. Thus, the optimum blending condition of the biomass based on the results of this study was found to be 5 while oxygen enrichment reduced the increase of UBC that occurred during combustion of blended biomass and coal.

Energy utilisation of biowaste - Sunflower-seed hulls for co-firing with coal

Energy Technology Data Exchange (ETDEWEB)

Raclavska, Helena; Juchelkova, Dagmar; Roubicek, Vaclav; Matysek, Dalibor [VSB-Technical University of Ostrava, 17. listopadu 15, CZ-70833 Ostrava (Czech Republic)

2011-01-15

Sunflower-seed hulls (SSH) represent a source of combustible biomass characterised by high contents of potassium and phosphorus and a low silica content. The relatively high net calorific value of 20 MJ/kg d.m. is mainly influenced by the lignin content. Potassium and phosphorus are very important elements in biomass combustion for fuel, influencing slagging and fouling problems. Mixtures with different ratios of brown coal and sunflower-seed hulls (0-22% SSH) were co-fired in the Olomouc power plant. The behaviour of elements in the fly ash and the bottom ash (SiO{sub 2}, Al{sub 2}O{sub 3}, K{sub 2}O, P{sub 2}O{sub 5}, Zn, Cu and Cd) varied in relation to the amount of SSH added to the coal. The fly ash from the co-firing of 20% SSH with coal had a high content of water-leachable sulphates and total dissolved solids. The utilisation of fly ash in civil engineering (land reclamation) should fulfil criteria established by the Council Decision 2003/33/EC for non-hazardous waste. To ensure that the required water-leachable sulphate concentrations are within regulatory limits the fuel may contain a maximum of 14% SSH. (author)

Improving the strength of ceramics by controlling the interparticle forces and rheology of the ceramic suspensions

International Nuclear Information System (INIS)

Chou, Yi-Ping

2001-01-01

This thesis describes a study of the modification of the interparticle forces of colloidal ceramic particles in aqueous suspensions in order to improve the microstructural homogeneity, and hence the reliability and mechanical performances, of subsequently formed ceramic compacts. A concentrated stable fine ceramic powder suspension has been shown to be able to generate a higher density of a ceramic product with better mechanical, and also electrical, electrochemical and optical, properties of the ceramic body. This is because in a colloidally stable suspension there are no aggregates and so defect formation, which is responsible for the ceramic body performance below its theoretical maximum, is reduced. In order to achieve this, it is necessary to form a well dispersed ceramic suspension by ensuring the interparticle forces between the particles are repulsive, with as a high a loading with particles as possible. By examining the rheological behaviour and the results of Atomic Force Microscope, the dispersion state of the suspensions and hence the interparticle forces can be analysed. In this study, concentrated ceramic suspensions were made from two kinds of zirconia powders, monoclinic (DK1) and yttria partially stabilised (HSY3) zirconia, in the presence of a dispersant, 4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt (Tiron), in aqueous system. The optimum dispersant concentrations, where the viscosity and rheological moduli are the entire minimum, for DK1 and HSY3 suspensions, respectively, are 0.625% and 0.1%. The modifications of the interparticle forces were also achieved by pH adjustment and it was found that both of the suspensions at the optimum dispersant concentration were stable over the pH range 7 ∼ 10, which coincide with the results of the electrophoretic mobility measurements. Ceramic compacts have then been made by slip casting the suspensions of different dispersant concentration, followed by firing procedure. Mechanical properties of

A ferrite LTCC based dual purpose helical antenna providing bias for tunability

KAUST Repository

Ghaffar, Farhan A.

2015-03-30

Typically, magnetically tunable antennas utilize large external magnets or coils to provide the magneto-static bias. In this work, we present a novel concept of combining the antenna and the bias coil in one structure. A helical antenna has been optimized to act as the bias coil in a ten layer ferrite LTCC package, thus performing two functions. This not only reduces the overall size of the system by getting rid of the external bias source but also eliminates demagnetization effect (fields lost at air-to-substrate interface), which reduces the required magneto-static field strength and makes the design efficient. RF choking inductor and DC blocking capacitor have been monolithically integrated as package elements to allow the magnetostatic and microwave excitation at the same time. The design has been optimized for its low frequency and high frequency performance in two different simulators. A measured tuning range of 10% is achieved at a center frequency of 13 GHz. The design is highly suitable for low cost, compact, light-weight and tunable microwave systems. © 2002-2011 IEEE.

A ferrite LTCC based dual purpose helical antenna providing bias for tunability

KAUST Repository

Ghaffar, Farhan A.; Shamim, Atif

2015-01-01

Typically, magnetically tunable antennas utilize large external magnets or coils to provide the magneto-static bias. In this work, we present a novel concept of combining the antenna and the bias coil in one structure. A helical antenna has been optimized to act as the bias coil in a ten layer ferrite LTCC package, thus performing two functions. This not only reduces the overall size of the system by getting rid of the external bias source but also eliminates demagnetization effect (fields lost at air-to-substrate interface), which reduces the required magneto-static field strength and makes the design efficient. RF choking inductor and DC blocking capacitor have been monolithically integrated as package elements to allow the magnetostatic and microwave excitation at the same time. The design has been optimized for its low frequency and high frequency performance in two different simulators. A measured tuning range of 10% is achieved at a center frequency of 13 GHz. The design is highly suitable for low cost, compact, light-weight and tunable microwave systems. © 2002-2011 IEEE.

Economic evaluation of pre-combustion CO2-capture in IGCC power plants by porous ceramic membranes

International Nuclear Information System (INIS)

Franz, Johannes; Maas, Pascal; Scherer, Viktor

2014-01-01

Highlights: • Process simulations of IGCC with pre-combustion capture via membranes were done. • Most promising technology is the water–gas-shift-membrane-reactor (WGSMR). • Energetic evaluations showed minimum efficiency loss of 5.8%-points for WGSMR. • Economic evaluations identified boundary limits of membrane technology. • Cost of electricity for optimum WGSMR-case is 57 €/MW h under made assumptions. - Abstract: Pre-combustion-carbon-capture is one of the three main routes for the mitigation of CO 2 -emissions by fossil fueled power plants. Based on the data of a detailed technical evaluation of CO 2 -capture by porous ceramic membranes (CM) and ceramic membrane reactors (WGSMR) in an Integrated-Gasification-Combined-Cycle (IGCC) power plant this paper focuses on the economic effects of CO 2 -abatement. First the results of the process simulations are presented briefly. The analysis is based on a comparison with a reference IGCC without CO 2 -capture (dry syngas cooling, bituminous coal, efficiency of 47.4%). In addition, as a second reference, an IGCC process with CO 2 removal based on standard Selexol-scrubbing is taken into account. The most promising technology for CO 2 -capture by membranes in IGCC applications is the combination of a water gas shift reactor and a H 2 -selective membrane into one water gas shift membrane reactor. For the WGSRM-case efficiency losses can be limited to about 6%-points (including losses for CO 2 compression) for a CO 2 separation degree of 90%. This is a severe reduction of the efficiency loss compared to Selexol (10.3% points) or IGCC–CM (8.6% points). The economic evaluation is based on a detailed analysis of investment and operational costs. Parameters like membrane costs and lifetime, costs of CO 2 -certificates and annual operating hours are taken into account. The purpose of these evaluations is to identify the minimum cost of electricity for the different capture cases for the variation of the boundary

ENVIRONMENTAL AND SUSTAINABLE TECHNOLOGY EVALUATION: BIOMASS CO-FIRING IN INDUSTRIAL BOILERS--MINNESOTA POWER'S RAPIDS ENERGY CENTER

Science.gov (United States)

The U.S. EPA operates the Environmental and Sustainable Technology Evaluation (ESTE) program to facilitate the deployment of innovative technologies through performance verification and information dissemination. This ESTE project involved evaluation of co-firing common woody bio...

Biomass co-firing in coal power plants in the Netherlands. Effects on performance and air pollutant emissions

Energy Technology Data Exchange (ETDEWEB)

Smekens, K. [ECN Policy Studies, Petten (Netherlands)

2013-07-15

This note is intended for use in the UNECE (United Nations Economic Commission for Europe)-EGTEI (Expert Group on Techno-Economic Issues) work related to cost of emission reduction technologies for large combustion plants (LCP). This work is coordinated by KIT (Karlsruhe) and CITEPA (Paris). As the Netherlands is considered to be a valuable country for data regarding biomass co-firing in large coal fired power plants, EGTEI expressed its interest on data ECN has available. For this purpose, based on available data from annual environmental reports of power plants, ECN has looked into the relationship between the percentage of co -firing and the plant performance. It should be noted that the evaluation has been based on annual data, not on real-time simultaneous measurements of the different parameters mentioned in this note. Cumulative annual data give no insights in e.g. the effects of the load factor, of start-ups or shut-downs, seasonal circumstances, fuel qualities, etc. Therefore, the findings in this report should be treated with due care and not be generalised.

Ceramic sealants prepared by polymer pyrolysis

Science.gov (United States)

Hong, Sung Jin; Kim, Deug Joong; Yoo, Young Sung

2011-02-01

The formation and properties of ceramic seals for SOFC applications prepared by polymer pyrolysis are investigated. A mixture with polymethylsiloxane and fillers are pyrolyzed in a N2 atmosphere. The coefficient of thermal expansion of the ceramic composites was controlled by fillers with a high coefficient of thermal expansion such as AlCo. The morphology of the ceramic composites derived from the mixture with polymethylsiloxane and fillers is composed of fillers embedded in a Si-O-C glass matrix. The thermal expansion behavior and sealing characteristics are measured and discussed

Surface preparation for high purity alumina ceramics enabling direct brazing in hydrogen atmospheres

Science.gov (United States)

Cadden, Charles H.; Yang, Nancy Yuan Chi; Hosking, Floyd M.

2001-01-01

The present invention relates to a method for preparing the surface of a high purity alumina ceramic or sapphire specimen that enables direct brazing in a hydrogen atmosphere using an active braze alloy. The present invention also relates to a method for directly brazing a high purity alumina ceramic or sapphire specimen to a ceramic or metal member using this method of surface preparation, and to articles produced by this brazing method. The presence of silicon, in the form of a SiO.sub.2 -containing surface layer, can more than double the tensile bond strength in alumina ceramic joints brazed in a hydrogen atmosphere using an active Au-16Ni-0.75 Mo-1.75V filler metal. A thin silicon coating applied by PVD processing can, after air firing, produce a semi-continuous coverage of the alumina surface with a SiO.sub.2 film. Room temperature tensile strength was found to be proportional to the fraction of air fired surface covered by silicon-containing films. Similarly, the ratio of substrate fracture versus interface separation was also related to the amount of surface silicon present prior to brazing. This process can replace the need to perform a "moly-manganese" metallization step.

Raw materials from the region of Rio Claro - SP for the manufacture of ceramic coatings: technological characteristics and geological-technological modeling

International Nuclear Information System (INIS)

Cunha, R.A.; Roveri, C.D.; Maestrelli, S.C.

2016-01-01

The Santa Gertrudes Ceramic Polo (PCSG) is the largest national producer of ceramic tiles, located in east-central region of Sao Paulo, encompassing different cities. PCSG uses various clays as the main raw material from the Corumbatai Formation, which is inserted in the Sedimentary Basin of Parana, with more than 1.5 square kilometers. In this context, X-ray diffractograms of samples from different areas of PCSG were used for application of the cluster analysis. Aiming to group the samples in families and subsequently to seek the most representative for the complete analysis. Also, ceramic tests were made by the following methods: the green bulk density after pressing, flexural strength modulus for green. , tests were conducted after firing at 1070 °C and 1120 °C: apparent density after drying, flexural modulus; after firing: apparent density after firing, water absorption linear shrinkage sintering, apparent porosity, modulus of resistance to bending after burning. Further, from the georeferenced sample were created tables for industry in the area, to facilitate the identification of new sample by XRD. Furthermore, the 3D model of the region was developed from the interesting characteristics for ceramic use, using Micromine Mining Software, Enterprise Micromine. (author)

Field test corrosion experiences when co-firing straw and coal: 10 year status within Elsam

DEFF Research Database (Denmark)

Frandsen, Rasmus Berg; Montgomery, Melanie; Larsen, Ole Hede

2007-01-01

and straw at the 150 MW pulverized coal fired boiler Studstrup unit 1. Two exposure series lasting 3000 hours each were performed for co-firing 10 and 20% of straw (% energy basis) with coal. Using built in test tubes in the hot end of the actual superheaters and air/water cooled corrosion probes...... to 575 degrees C and for the flue gas from 1025 to 1300 degrees C. All these test tubes have been removed during the last three years at one year intervals for corrosion studies. The corrosion studies performed on all investigated tubes included measurements of the corrosion attack, light optical...

Co-firing of oil sludge with coal-water slurry in an industrial internal circulating fluidized bed boiler.

Science.gov (United States)

Liu, Jianguo; Jiang, Xiumin; Zhou, Lingsheng; Wang, Hui; Han, Xiangxin

2009-08-15

Incineration has been proven to be an alternative for disposal of sludge with its unique characteristics to minimize the volume and recover energy. In this paper, a new fluidized bed (FB) incineration system for treating oil sludge is presented. Co-firing of oil sludge with coal-water slurry (CWS) was investigated in the new incineration system to study combustion characteristics, gaseous pollutant emissions and ash management. The study results show the co-firing of oil sludge with CWS in FB has good operating characteristic. CWS as an auxiliary fuel can flexibly control the dense bed temperatures by adjusting its feeding rate. All emissions met the local environmental requirements. The CO emission was less than 1 ppm or essentially zero; the emissions of SO(2) and NO(x) were 120-220 and 120-160 mg/Nm(3), respectively. The heavy metal analyses of the bottom ash and the fly ash by ICP/AES show that the combustion ashes could be recycled as soil for farming.

CO2 laser photoacoustic detection of ammonia emitted by ceramic industries.

Science.gov (United States)

Sthel, M S; Schramm, D U; Lima, G R; Carneiro, L; Faria, R T; Castro, M P P; Alexandre, J; Toledo, R; Silva, M G; Vargas, H

2011-01-01

A homemade photoacoustic spectrometer has been constructed for monitoring gas emission from several sources. Numerous air pollutant gases are emitted exhaust of industries, vehicles and power plants. The photoacoustic technique is extremely sensitive and selective in detecting various gases. This work focuses on the gas emitted by the ceramic industry in northern Rio de Janeiro State in Brazil, the ceramic industry plays a remarkable role in the economy activity of this region, in recent years, this region developed into a significant red ceramic complex. The potential impact on the atmospheric environment of the region due to gaseous pollutant emissions from these anthropogenic sources needs to be evaluated. In this work we identified NH3 present in the samples collected in the kiln of a ceramic plant, in the concentration range of 33-52 ppmV. The ammonia gas present in our collected samples might come from the excess nitrogen in the manure soil from where the ceramic material was extracted. This soil was used for the sugarcane culture which is another important economic activity of this region. Copyright © 2010 Elsevier B.V. All rights reserved.

Burning behavior in a poor-ventilation compartment fire - ghosting fire

International Nuclear Information System (INIS)

Sugawa, Osami; Kawagoe, Kunio; Oka, Yasushi

1991-01-01

We investigated compartment fire behavior under poor-ventilation conditions using a methyl alcohol pool fire as the source with a diameter of 30 cm set in a tight box of 2 m (W)x3 m(L)x0.6 m(H). The temperatures in the box and the fuel, gas concentrations of CO, CO 2 , and O 2 , and the fuel consumption rate were measured simultaneously. The burning fuel surface level was kept constant during the test by means of an automatic fuel supply system. It was found that the flame begun to detach from the fuel surface as the oxygen concentration decreased to about 16%, and the color changed to pale blue. The flame detached completely from the fuel and a 'ghosting flame' was observed just under the ceiling which showed a thin pale blue flame and looked line an aurora. The oxygen concentration measured in the ghosting period under the ceiling was 9-10 vol%, and CO 2 was 4.5 vol% so that the oxygen of such concentration acted as in inert gas. CO 2 gas concentration looked almost a single-layer with gradient in the upper half part in ghosting period. Temperatures in the same layer decreased after ghosting occurred with gradient. For poor-ventilated fires, air exchange rate as 1.6-2.4 times/hr was estimated in the test; the burning rate decreased finally to about 1/6 of the fuel controlled fire. It has been tacitly assumed that the flame (reaction zone) and pyrolyzing material area (fuel) exit in almost the same zone, but ghosting fire is not necessarily the case. Therefore, extinguishment of ghosting fire which may occur in an enclosure with fuel and energy rich but poor-ventilation such as a power plant will be extremely difficult. (orig.)

Ceramic media amended with metal oxide for the capture of viruses in drinking water.

Science.gov (United States)

Brown, J; Sobsey, M D

2009-04-01

Ceramic materials that can adsorb and/or inactivate viruses in water may find widespread application in low-tech drinking-water treatment technologies in developing countries, where porous ceramic filters and ceramic granular media filters are increasingly promoted for that purpose. We examined the adsorption and subsequent inactivation of bacteriophages MS2 and (phiX-174 on five ceramic media in batch adsorption studies to determine media suitability for use in a ceramic water filter application. The media examined were a kaolinitic ceramic medium and four kaolinitic ceramic media amended with iron or aluminium oxides that had been incorporated into the kaolinitic clays before firing. Batch adsorption tests indicate increased sorption and inactivation of surrogate viruses by media amended with Fe and Al oxide, with FeOOH-amended ceramic inactivating all bacteriophages up to 8 log10. Unmodified ceramic was a poor adsorbent of bacteriophages at less than 1 log10 adsorption-inactivation and high recovery of sorbed phages. These studies suggest that contact with ceramic media, modified with electropositive Fe or Al oxides, can reduce bacteriophages in waters to a greater extent than unmodified ceramic.

Sintering behavior of porous wall tile bodies during fast single-firing process

Directory of Open Access Journals (Sweden)

Sidnei José Gomes Sousa

2005-06-01

Full Text Available In ceramic wall tile processing, fast single-firing cycles have been widely used. In this investigation a fast single-firing porous wall tile mixture was prepared using raw materials from the North Fluminense region.Specimens were obtained by uniaxial pressing and sintered in air at various temperatures (1080 - 1200 °C using a fast-firing cycle (60 minutes. Evolution of the microstructure was followed by XRD and SEM. The results revealed that the main phases formed during the sintering step are anorthite, gehlenite and hematite. It appears that the sintering process is characterized by the presence of a small amount of a liquid phase below 1140 °C. As a result, the microstructure of the ceramic bodies showed a network of small dense zones interconnected with a porous phase. In addition, the strength of the material below 1140 °C appeared to be related to the type and quantity of crystalline phases in the sintered bodies.

DOPO-Modified Two-Dimensional Co-Based Metal-Organic Framework: Preparation and Application for Enhancing Fire Safety of Poly(lactic acid).

Science.gov (United States)

Hou, Yanbei; Liu, Longxiang; Qiu, Shuilai; Zhou, Xia; Gui, Zhou; Hu, Yuan

2018-03-07

Co-based metal-organic framework (Co-MOF) nanosheets were successfully synthesized by the organic ligands with Schiff base structure. The laminated structure gives Co-MOF nanosheets a great advantage in the application in the flame retardant field. Meanwhile, -C═N- from Schiff base potentially provides active sites for further modification. In this work, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) was used to modify Co-MOF (DOPO@Co-MOF) to further enhance its flame retardant efficiency. It is attractive that DOPO has a synergistic effect with Co-MOF on improving fire safety of poly(lactic acid) (PLA). The obvious decrease in the values of peak heat release (27%), peak smoke production (56%), and total CO yield (20%) confirmed the enhanced fire safety of PLA composites. The possible flame retardant mechanism was proposed based on characterization results. Moreover, the addition of DOPO@Co-MOF had a positive influence on the mechanical performance, including tensile properties and impact resistance. This work designed and synthesized two-dimensional MOFs with active groups. As-prepared Co-MOF with expected structure shows a novel direction of preparing MOFs for flame retardant application.

Scrubbing system design for CO2 capture in coal-fired power plants

International Nuclear Information System (INIS)

Heischkamp, Elizabeth

2017-01-01

Within the last decades a continuous tightening of environmental regulations has been observed in several countries around the world. These include restriction of anthropogenic CO 2 emissions, since they are considered responsible for intensifying global warming. Coal-fired power plants represent a good possibility for capturing CO 2 before it is emitted in the atmosphere, thereby contributing to combat global warming. This work focuses on reducing the CO 2 emissions of such a power plant by 90 %. For this purpose a hard coal power plant is retrofitted with a chemical absorption using different solutions of piperazine promoted potassium carbonate. The resulting power plant's efficiency losses have been accounted for. A comparison of different scenarios such as the variation of operating parameters offer an insight in detecting suitable operating conditions that will allow to minimize efficiency penalties. Simulation details are provided along with a technical and an economic analysis.

Comparison of a burning mass ceramics coating in laboratory furnace and instrustrial furnace

International Nuclear Information System (INIS)

Soares, R.A.L.; Castro, J.R. de S.

2012-01-01

This work intends to analyze the differences obtained in the technological properties of a ceramic coating after firing in two distinct environments, laboratory furnace and industrial furnace. For this, was characterized a ceramic mass used in the production of porous coating. The analyzes were performed chemical, mineralogical and thermal mass in that. The specimens were obtained by compacting and burned in the maximum temperature of 1140 deg C in two furnaces, laboratory and industrial. The technological tests were performed linear shrinkage, water absorption, bulk density and mechanical strength. The microstructure was evaluated by ray-X diffraction and scanning electron microscopy. The results showed that both furnaces provided significant differences in analyzed specimens, such as increased strength and low water absorption in the fired samples in a laboratory furnace, for example. (author)

Structural ceramics containing electric arc furnace dust.

Science.gov (United States)

Stathopoulos, V N; Papandreou, A; Kanellopoulou, D; Stournaras, C J

2013-11-15

In the present work the stabilization of electric arc furnace dust EAFD waste in structural clay ceramics was investigated. EAFD was collected over eleven production days. The collected waste was characterized for its chemical composition by Flame Atomic Absorption Spectroscopy. By powder XRD the crystal structure was studied while the fineness of the material was determined by a laser particle size analyzer. The environmental characterization was carried out by testing the dust according to EN12457 standard. Zn, Pb and Cd were leaching from the sample in significant amounts. The objective of this study is to investigate the stabilization properties of EAFD/clay ceramic structures and the potential of EAFD utilization into structural ceramics production (blocks). Mixtures of clay with 2.5% and 5% EAFD content were studied by TG/DTA, XRD, SEM, EN12457 standard leaching and mechanical properties as a function of firing temperature at 850, 900 and 950 °C. All laboratory facilities maintained 20 ± 1 °C. Consequently, a pilot-scale experiment was conducted with an addition of 2.5% and 5% EAFD to the extrusion mixture for the production of blocks. During blocks manufacturing, the firing step reached 950 °C in a tunnel kiln. Laboratory heating/cooling gradients were similar to pilot scale production firing. The as produced blocks were then subjected to quality control tests, i.e. dimensions according to EN772-17, water absorbance according to EN772-6, and compressive strength according to EN772-1 standard, in laboratory facilities certified under EN17025. The data obtained showed that the incorporation of EAFD resulted in an increase of mechanical strength. Moreover, leaching tests performed according to the Europeans standards on the EAFD-block samples showed that the quantities of heavy metals leached from crushed blocks were within the regulatory limits. Thus the EAFD-blocks can be regarded as material of no environmental concern. Copyright © 2013 Elsevier B

Evaluation of BaZr0.1Ce0.7Y0.2O3-δ-based proton-conducting solid oxide fuel cells fabricated by a one-step co-firing process

International Nuclear Information System (INIS)

Sun Wenping; Wang Yanfei; Fang Shumin; Zhu Zhiwen; Yan Litao; Liu Wei

2011-01-01

Proton-conducting solid oxide fuel cells, incorporating BaZr 0.1 Ce 0.7 Y 0.2 O 3-δ (BZCY) electrolyte, NiO-BZCY anode, and Sm 0.5 Sr 0.5 CoO 3-δ -Ce 0.8 Sm 0.2 O 2-δ (SSC-SDC) cathode, were successfully fabricated by a combined co-pressing and printing technique after a one-step co-firing process at 1100, 1150, or 1200 o C. Scanning electron microscope (SEM) results revealed that the co-firing temperature significantly affected not only the density of the electrolyte membrane but the grain size and porosity of the electrodes. Influences of the co-firing temperature on the electrochemical performances of the single cells were also studied in detail. Using wet hydrogen (2% H 2 O) as the fuel and static air as the oxidant, the cell co-fired at 1150 o C showed the highest maximum power density (PD max ) of 552 and 370 mW cm -2 at 700 and 650 o C, respectively, while the one co-fired at 1100 o C showed the highest PD max of 276 and 170 mWcm -2 at 600 and 550 o C, respectively. The Arrhenius equation was proposed to analyze the dependence of the PD max on the operating temperature, and revealed that PD max of the cell co-fired at a lower temperature was less dependent on operating temperature. The influences of the co-firing temperature on the resistances of the single cells, which were estimated from the electrochemical impedance spectroscopy measured under open circuit conditions, were also investigated.

Metallizing of machinable glass ceramic

International Nuclear Information System (INIS)

Seigal, P.K.

1976-02-01

A satisfactory technique has been developed for metallizing Corning (Code 9658) machinable glass ceramic for brazing. Analyses of several bonding materials suitable for metallizing were made using microprobe analysis, optical metallography, and tensile strength tests. The effect of different cleaning techniques on the microstructure and the effect of various firing temperatures on the bonding interface were also investigated. A nickel paste, used for thick-film application, has been applied to obtain braze joints with strength in excess of 2000 psi

A Glass Ceramic Derived from High TiO2-Containing Slag – Microstructure Development and Mechanical Behaviour

Czech Academy of Sciences Publication Activity Database

Wu, J. P.; Rawlings, R. D.; Boccaccini, A. R.; Dlouhý, Ivo; Chlup, Zdeněk

2006-01-01

Roč. 89, č. 8 (2006), s. 2426-2433 ISSN 1551-2916 R&D Projects: GA ČR(CZ) GA106/06/0724; GA ČR(CZ) GA106/05/0495 Institutional research plan: CEZ:AV0Z20410507 Keywords : glass ceramic s * fracture toughness * flexural strength Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass

Development of ceramic glaze with photocatalytic activity

International Nuclear Information System (INIS)

Tezza, V.B.; Uggioni, E.; Carrera, A.A. Duran; Bernardin, A.M.

2011-01-01

Glazes were developed by adding anatase in commercial ceramic plates as an agent of photocatalysis. The glazes were coated on ceramic tiles, which were fired between 800 and 1000°C. The formulations were characterized (SEM, XRD), and the wettability was determined by measuring the water contact angle. The microstructural analysis (SEM) showed that the anatase particles can disperse properly in the glaze matrix. The X-ray diffraction shows that from 1000°C, the glaze becomes very reactive, and particles of anatase are transformed into titanite or rutile, depending on the glaze used. The determination of the contact angle shows the clear influence of the glaze type and sintering temperature on the wettability characteristics of the obtained layer. (author)

Structural, electric and dielectric properties of Eu-doped SrBi2Nb2O9 ceramics obtained by co-precipitation route

Directory of Open Access Journals (Sweden)

Mohamed Afqir

2018-03-01

Full Text Available This paper presents a study of the structure and dielectric properties of Eu-doped SrBi2Nb2O9 ceramics prepared by co-precipitation route and sintered at 850 °C. The materials were examined using XRD and FTIR methods. XRD data indicated the formation of well crystallized structure of the pure and doped SrBi2Nb2O9, without the presence of undesirable phases. FTIR spectra do not bring a significant shift in the band positions. Moreover, the AC conductivity, dielectric constant and dielectric loss of the ceramics were determined through the frequency range [50 kHz–1 MHz]. In particular, the dielectric constant (ε′ and dielectric losses (tan δ of the SrBi2Nb2O9 and SrBi1.6Eu0.4Nb2O9 ceramics were measured as a function of temperature at various frequencies.

Influence of sintering temperature in red ceramic with addition of mill scale; Influencia da temperatura de sinterizacao em ceramica vermelha com adicao de carepa/residuo de laminacao

Energy Technology Data Exchange (ETDEWEB)

Arnt, A.B.C.; Rocha, M.R.; Bernardin, A.M.; Meller, J.G., E-mail: anb@unesc.ne [Universidade do Extremo Sul Catarinense (UNESC), Criciuma, SC (Brazil). Engenharia de Materiais. Lab. de Fenomenos de Superficies e Tratamentos Termicos

2010-07-01

This study aimed to evaluate the influence of sintering temperature in a red ceramic body with the addition of mill scale. This residue consists of oxides of iron had to replace the function of pigments used in ceramic materials. After chemical characterization, by X-ray diffraction, X-ray fluorescence and scanning electron microscopy, this residue was added at a rate of 5% in commercial ceramic past. The formulations were subjected to different burn temperatures of around 950 deg C, 1000 deg C and 1200 deg C. The formulations were evaluated for physical loss to fire, linear firing shrinkage, water absorption and flexural strength by 3 and intensity of tone. The results indicate that the different firing temperatures influence the strength and stability of tone in the formulations tested. (author)

Quantitative analysis of crystalline and remaining glass phases in CaO-B2O3-SiO2 ternary system glass ceramics

International Nuclear Information System (INIS)

He Ming; Wu Mengqiang; Zhang Shuren; Zhou Xiaohua; Zhang Ting; Chen Song

2010-01-01

Research highlights: → As for CBS ternary system glass ceramics, due to the complex phase compositions, many methods could be difficult to determine quantitatively the absolute amounts of crystalline and remaining oxides. In this study, an available method based on the Rietveld method was used to quantitatively analyze the relative weight fraction and densities of crystalline phases. These above data are used to obtain a table of both relative weight fraction of crystalline phases and densities of all phases including CBS LTCC. Using volume additivity rule, it is possible to analysis quantitatively the absolute weight fraction of crystalline phases and also the oxides molar content in the remaining glass. - Abstract: Based on Rietveld method of X-ray techniques and volume additivity rule, a new method was developed to quantitatively analyze the phase composition of CaO-B 2 O 3 -SiO 2 ternary system glass ceramics. Lattice parameters, densities and relative weight fractions of crystalline phases in CaO-B 2 O 3 -SiO 2 ternary system were obtained by X-ray diffraction (XRD) refinement. According to the relative weight fraction of crystalline phases and densities of various components, the volume additivity rule was revealed by calculating the absolute weight fraction of crystalline phases of CaO-B 2 O 3 -SiO 2 glass ceramics. In addition, molar contents of the oxides in the remaining glass can also be determined by this method. Comparing this method with internal standard method, it is found that the maximum deviations of the crystallinity and the absolute weight fraction of crystalline phases are less than 2.6% and 2.9%, respectively. As a result, quantitative evaluation of CaO-B 2 O 3 -SiO 2 ternary system glass ceramics can be achieved using this method.

Micropreconcentrator in LTCC Technology with Mass Spectrometry for the Detection of Acetone in Healthy and Type-1 Diabetes Mellitus Patient Breath

Directory of Open Access Journals (Sweden)

Artur Rydosz

2014-10-01

Full Text Available Breath analysis has long been recognized as a potentially attractive method for the diagnosis of several diseases. The main advantage over other diagnostic methods such as blood or urine analysis is that breath analysis is fully non-invasive, comfortable for patients and breath samples can be easily obtained. One possible future application of breath analysis may be the diagnosing and monitoring of diabetes. It is, therefore, essential, to firstly determine a relationship between exhaled biomarker concentration and glucose in blood as well as to compare the results with the results obtained from non-diabetic subjects. Concentrations of molecules which are biomarkers of diseases’ states, or early indicators of disease should be well documented, i.e., the variations of abnormal concentrations of breath biomarkers with age, gender and ethnic issues need to be verified. Furthermore, based on performed measurements it is rather obvious that analysis of exhaled acetone as a single biomarker of diabetes is unrealistic. In this paper, the author presents results of his research conducted on samples of breath gas from eleven healthy volunteers (HV and fourteen type- 1 diabetic patients (T1DM which were collected in 1-l SKC breath bags. The exhaled acetone concentration was measured using mass spectrometry (HPR-20 QIC, Hiden Analytical, Warrington, UK coupled with a micropreconcentrator in LTCC (Low Temperature Cofired Ceramic. However, as according to recent studies the level of acetone varies to a significant extent for each blood glucose concentration of single individuals, a direct and absolute relationship between blood glucose and acetone has not been proved. Nevertheless, basing on the research results acetone in diabetic breath was found to be higher than 1.11 ppmv, while its average concentration in normal breath was lower than 0.83 ppmv.

Structural, thermal, and optical properties of Er3+/Yb3+ co-doped oxyhalide tellurite glasses, glass-ceramics and ceramics

International Nuclear Information System (INIS)

Joshi, C.; Rai, R.N.; Rai, S.B.

2012-01-01

Glass-ceramics and ceramics containing nano-crystals of different phases doped with Er 3+ /Yb 3+ ions have been successfully prepared by heat treatment of the precursor oxyhalide glasses synthesized by the melt-quench method. X-ray diffraction patterns and transmission electron microscopy (TEM) images verify the precipitation of nano-crystals. Emission of Er 3+ enhances several times when Yb 3+ ion is added with the matrix. The Stark splitting and the intensity of different emission bands increase to a great extent when we approach to ceramics from glasses via glass-ceramics. The intensity of the blue and green emission bands increases much faster than the red and NIR emission bands. Intense upconversion emission observed by the naked eye has been quantified in terms of standard chromaticity diagram (CIE). Power dependence study shows that the upconversion of NIR radiation to visible radiation takes place mainly via photon avalanche (PA) process.

Nonaqueous slip casting of high temperature ceramic superconductors using an investment casting technique

Science.gov (United States)

Hooker, Matthew W. (Inventor); Taylor, Theodore D. (Inventor); Wise, Stephanie A. (Inventor); Buckley, John D. (Inventor); Vasquez, Peter (Inventor); Buck, Gregory M. (Inventor); Hicks, Lana P. (Inventor)

1993-01-01

A process for slip casting ceramic articles that does not employ parting agents and affords the casting of complete, detailed, precision articles that do not possess parting lines is presented. This process is especially useful for high temperature superconductors and water-sensitive ceramics. A wax pattern for a shell mold is provided, and an aqueous mixture of a calcium sulfate-bonded investment material is applied as a coating to the wax pattern. The coated wax pattern is then dried, followed by curing to vaporize the wax pattern and leave a shell mold of the calcium sulfate-bonded investment material. The shell mold is cooled to room temperature, and a ceramic slip, created by dispersing a ceramic powder in an organic liquid, is poured therein. After a ceramic shell of desired thickness or a solid article has set up in the shell mold, excess ceramic slip is poured out. The shell mold is misted with water and peeled away from the ceramic article, after which the ceramic is fired to provide a complete, detailed, precision, high temperature superconductive ceramic article without parting lines. The casting technique may take place in the presence of a magnetic field to orient the ceramic powders during the casting process.