Study on Modified Water Glass Used in High Temperature Protective Glass Coating for Ti-6Al-4V Titanium Alloy

Directory of Open Access Journals (Sweden)

Shuang Yang

2018-04-01

Full Text Available Sodium silicate water glass was modified with sodium polyacrylate as the binder, the composite slurry used for high-temperature oxidation-resistant coating was prepared by mixing glass powder with good lubrication properties in the binder. The properties of the modified binder and high-temperature oxidation resistance of Ti-6Al-4V titanium alloy coated with composite glass coating were studied by XRD, SEM, EDS, TG-DSC and so on. Results showed that sodium polyacrylate modified water glass could obviously improve the suspension stability of the binder, the pyrolytic carbon in the binder at high temperature could increase the surface tension in the molten glass system, and the composite glass coating could be smooth and dense after heating. Pyrolytic carbon diffused and combined with oxygen in the coating under the heating process to protect the titanium alloy from oxidation. The thickness of the oxide layer was reduced 51% after applying the high-temperature oxidation-resistant coating. The coating also showed a nearly 30% reduction in friction coefficient due to the boundary lubricant regime. During cooling, the coating could be peeled off easily because of the mismatched CTE between the coating and substrate.

Validation Assessment of a Glass-to-Metal Seal Finite-Element Model

Energy Technology Data Exchange (ETDEWEB)

Jamison, Ryan Dale [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Buchheit, Thomas E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Emery, John M [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Romero, Vicente J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stavig, Mark E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Newton, Clay S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brown, Arthur [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-10-01

Sealing glasses are ubiquitous in high pressure and temperature engineering applications, such as hermetic feed-through electrical connectors. A common connector technology are glass-to-metal seals where a metal shell compresses a sealing glass to create a hermetic seal. Though finite-element analysis has been used to understand and design glass-to-metal seals for many years, there has been little validation of these models. An indentation technique was employed to measure the residual stress on the surface of a simple glass-to-metal seal. Recently developed rate- dependent material models of both Schott 8061 and 304L VAR stainless steel have been applied to a finite-element model of the simple glass-to-metal seal. Model predictions of residual stress based on the evolution of material models are shown. These model predictions are compared to measured data. Validity of the finite- element predictions is discussed. It will be shown that the finite-element model of the glass-to-metal seal accurately predicts the mean residual stress in the glass near the glass-to-metal interface and is valid for this quantity of interest.

Effect of Al2O3 nano-filler on properties of glass-based seals for solid oxide fuel cells.

Science.gov (United States)

Lee, Dong Bok; Choi, Myong-Jae; Park, Sung; Lee, Jae Chun

2013-01-01

This study compares the viscosity and strength of three glass-based seals prepared with or without nano or micron-sized alumina powder used as filler material. Measurements of the viscosity and bending strength of the glass-based seals showed that addition of the nano-sized alumina powder to the glass increased both the high-temperature viscosity and the strength of the sintered glass matrix. Strength tests and observations of the microstructure of the fracture surface of the seal samples confirmed the strengthening of the glass network structure. Conversion of non-bridging oxygen to bridging oxygen is presumed to occur upon the addition of alumina to the glass sample. The strengthening of the alumina-glass composite seal was attributed to the alumina nano-filler and prolonged heat treatment at elevated temperatures.

Self-sealing multilayer coating for SiC/SiC composites

International Nuclear Information System (INIS)

Ferraris, M.; Appendino Montorsi, M.; Salvo, M.; Isola, C.; Kohyama, A.

1997-01-01

A double layer coating for SiC/SiC for fusion applications is proposed: the first layer consists in a homogeneous, crack free, glass-ceramic with high characteristic temperatures and thermal expansion coefficient compatible to the composite one; the second layer is amorphous and shows self-sealing properties above 700degC. The glass and the glass-ceramic materials used for this double layer coating do not contain lithium and boron oxide, making them particularly interesting for thermonuclear fusion applications. The self-sealing property of the double layer coating was valued by inducing cracks on the coatings and observing their reparation after heating. (author)

Stress Mapping in Glass-to-Metal Seals using Indentation Crack Lengths.

Energy Technology Data Exchange (ETDEWEB)

Strong, Kevin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Buchheit, Thomas E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Diebold, Thomas Wayne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Newton, Clay S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bencoe, Denise N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stavig, Mark E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jamison, Ryan Dale [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-08-01

Predicting the residual stress which develops during fabrication of a glass-to-metal compression seal requires material models that can accurately predict the effects of processing on the sealing glass. Validation of the predictions requires measurements on representative test geometries to accurately capture the interaction between the seal materials during a processing cycle required to form the seal, which consists of a temperature excursion through the glass transition temperature of the sealing glass. To this end, a concentric seal test geometry, referred to as a short cylinder seal, consisting of a stainless steel shell enveloping a commercial sealing glass disk has been designed, fabricated, and characterized as a model validation test geometry. To obtain data to test/validate finite element (FE) stress model predictions of this geometry, spatially-resolved residual stress was calculated from the measured lengths of the cracks emanating from radially positioned Vickers indents in the glass disk portion of the seal. The indentation crack length method is described, and the spatially-resolved residual stress determined experimentally are compared to FE stress predictions made using a nonlinear viscoelastic material model adapted to inorganic sealing glasses and an updated rate dependent material model for 304L stainless steel. The measurement method is a first to achieve a degree of success for measuring spatially resolved residual stress in a glass-bearing geometry and a favorable comparison between measurements and simulation was observed.

Stress Mapping in Glass-to-Metal Seals using Indentation Crack Lengths

Energy Technology Data Exchange (ETDEWEB)

Buchheit, Thomas E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Component & Systems Analysis; Strong, Kevin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Material Mechanics and Tribology; Newton, Clay S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Material Mechanics and Tribology; Diebold, Thomas Wayne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Material Mechanics and Tribology; Bencoe, Denise N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Electronic, Optical and Nano; Stavig, Mark E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Organic Materials Science; Jamison, Ryan Dale [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Transportation System Analysis

2017-08-01

Predicting the residual stress which develops during fabrication of a glass-to-metal compression seal requires material models that can accurately predict the effects of processing on the sealing glass. Validation of the predictions requires measurements on representative test geometries to accurately capture the interaction between the seal materials during a processing cycle required to form the seal, which consists of a temperature excursion through the glass transition temperature of the sealing glass. To this end, a concentric seal test geometry, referred to as a short cylinder seal, consisting of a stainless steel shell enveloping a commercial sealing glass disk has been designed, fabricated, and characterized as a model validation test geometry. To obtain data to test/validate finite element (FE) stress model predictions of this geometry, spatially-resolved residual stress was calculated from the measured lengths of the cracks emanating from radially positioned Vickers indents in the glass disk portion of the seal. The indentation crack length method is described, and the spatially-resolved residual stress determined experimentally are compared to FE stress predictions made using a nonlinear viscoelastic material model adapted to inorganic sealing glasses and an updated rate dependent material model for 304L stainless steel. The measurement method is a first to achieve a degree of success for measuring spatially resolved residual stress in a glass-bearing geometry and a favorable comparison between measurements and simulation was observed.

Self-cleaning glasses containing nanostructured titanium oxide

International Nuclear Information System (INIS)

Araujo, A.; Alves, A.K.; Berutti, F.A.; Bergmann, C.P.

2010-01-01

Using the electrospinning technique nanofibers of titanium oxide were synthesized. As precursor materials, titanium propoxide and a solution of polyvinylpyrrolidone were used. After the electrospinning process, the non-tissue material obtained was heat treated and characterized by X-ray diffraction to determine the phase crystallinity, and SEM to analyze the microstructure of the fibers. After ultrasound dispersion of this material in isopropyl alcohol, the glass coatings were made by dip-coating methodology. The removal velocity was kept constant, but the solution composition was varied to obtain a transparent and photo active film. The film was characterized by the contact angle of a water droplet in its surface (hydrophilicity), the transparency was evaluated using a spectrophotometer and the photocatalytic activity of the film was also evaluated. (author)

Glass-ceramic hermetic seals to high thermal expansion metals

Science.gov (United States)

Kramer, D.P.; Massey, R.T.

1987-04-28

A process for forming glass-ceramic materials from an alkaline silica-lithia glass composition comprising 60-72 mole-% SiO/sub 2/, 18-27 mole-% Li/sub 2/O, 0-5 mole-% Al/sub 2/O/sub 3/, 0-6 mole-% K/sub 2/O, 0-3 mole-% B/sub 2/O/sub 3/, and 0.5-2.5 mole-% P/sub 2/O/sub 5/, which comprises heating said glass composition at a first temperature within the 950-1050/degree/C range for 5-60 minutes, and then at a devitrification temperature within the 700-900/degree/C range for about 5-300 minutes to obtain a glass-ceramic having a thermal expansion coefficient of up to 210 x 10/sup /minus/7///degree/C. These ceramics form strong, hermetic seals with high expansion metals such as stainless steel alloys. An intermediate nucleation heating step conducted at a temperature within the range of 675-750/degree/C for 10-120 minutes may be employed between the first stage and the devitrification stage. 1 fig., 2 tabs.

Sealing of ceramic SOFC-components with glass seals; Fuegen von keramischen Komponenten der Hochtemperatur-Brennstoffzellen mittels Glas- und Glaskeramikloten

Energy Technology Data Exchange (ETDEWEB)

Schillig, Cora

2012-07-10

The solid oxide fuel cell (SOFC) converts chemical energy of a fuel directly into electrical energy. However, for the implementation of SOFC-technology in competition to conventional power plants costs have to be reduced. The use of an alternative tubular cell design without closed end would allow reducing costs during cell manufacturing. However, this change in design makes a gastight sealing inside the generator near the gas inlet necessary. Different ceramic materials with varying coefficients of thermal expansion have to be sealed gastight and electrical insulating at temperatures between 850 C and 1000 C to prevent the gases from mixing and an electrical shortcut between the cells. This work comprises analysis of commercially available glass and glass-ceramic systems manufactured by Schott Electronic Packaging, Areva T and D and Ferro Corporation. Additionally new developed sealing glass and glass-ceramic systems were investigated and all systems were characterized fundamentally for the use as sealing material in SOFC generators. Therefore different test assemblies and series were conducted. Essential characteristics of a suitable sealing system are a thermal expansion coefficient between 9,5 and 12 . 10{sup -6}K{sup -1}, a viscosity in the range between 10{sup 4} to 10{sup 6} dPa{sup *}s and a wetting angle smaller than 90 during the sealing process. Also unwanted chemical side reactions between the sealing partners must be prevented, because a change in the phase composition or the creation of new phases in the sealing material could endanger the stability of the seal. Heat cycles, particularly those during generator operation, cause deterioration of the sealing material and subsequent reduction in its ability to prevent mixing of the gases. Sealant leaks can drastically impact efficiency of the generator. In order to ensure optimum operation low leak rates around 2,3 . 10{sup -4} mbar l/sec/cm{sup 2} must be maintained. Especially glass and glass

Commercial alkaline earth boroaluminosilicate glasses for sealing solid oxide cell stacks. Part I: Development of glass-ceramic microstructure and thermomechanical properties

DEFF Research Database (Denmark)

Agersted, Karsten; Balic-Zunic, Tonci

2018-01-01

Sealing performance in solid oxide cell (SOC) stacks and the devitrification process of commercially available alkaline earth boroaluminosilicate glasses containing 48‐61 mol% SiO2, 18‐28 mol% CaO, 1‐7 mol% MgO, 7‐10 mol% Al2O3, 1‐11 mol% B2O3 plus minor amounts of Na2O, K2O, FeO, and TiO2 were...... investigated and quantified through analysis of phase assemblages as function of heat treatments above the glass transition temperatures using the electron microprobe and powder X‐ray diffraction. For two of these glasses devitrification behavior was compared to the devitrification behavior of similar glasses...... produced in the laboratory. Glasses were characterized after annealing in air at 800°C and 850°C for up to 6 weeks. Even though the glasses lie within a relatively narrow compositional range, sealing performance and the resulting microstructures differed significantly. Best thermomechanical properties...

Laser bioengineering of glass-titanium implants surface

Science.gov (United States)

Lusquiños, F.; Arias-González, F.; Penide, J.; del Val, J.; Comesaña, R.; Quintero, F.; Riveiro, A.; Boutinguiza, M.; Pascual, M. J.; Durán, A.; Pou, J.

2013-11-01

Osseointegration is the mean challenge when surgical treatments fight against load-bearing bone diseases. Absolute bone replacement by a synthetic implant has to be completed not only from the mechanics point of view, but also from a biological approach. Suitable strength, resilience and stress distribution of titanium alloy implants are spoiled by the lack of optimal biological characteristics. The inert quality of extra low interstitial titanium alloy, which make it the most attractive metallic alloy for biomedical applications, oppose to an ideal surface with bone cell affinity, and capable to stimulate bone attachment bone growth. Diverse laser treatments have been proven as effective tools to modify surface properties, such as wettability in contact to physiological fluids, or osteoblast guided and slightly enhanced attachment. The laser surface cladding can go beyond by providing titanium alloy surfaces with osteoconduction and osteoinduction properties. In this research work, the laser radiation is used to produce bioactive glass coatings on Ti6Al4V alloy substrates. Specific silicate bioactive glass compositions has been investigated to achieve suitable surface tension and viscosity temperature behavior during processing, and to provide with the required release of bone growth gene up regulation agents in the course of resorption mediated by physiological fluids. The produced coatings and interfaces, the surface osteoconduction properties, and the chemical species release in simulated physiological fluid were characterized by scanning electron microscopy (SEM), hot stage microscopy (HSM), X-ray diffraction (XRD), X ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR).

Glass ceramic seals to inconel

Science.gov (United States)

McCollister, Howard L.; Reed, Scott T.

1983-11-08

A glass ceramic composition prepared by subjecting a glass composition comprising, by weight, 65-80% SiO.sub.2, 8-16%, Li.sub.2 O, 2-8% , Al.sub.2 O.sub.3, 1-8% K.sub.2 O, 1-5% P.sub.2 O.sub.5 and 1.5-7% B.sub.2 O.sub.3, to the following processing steps of heating the glass composition to a temperature sufficient to crystallize lithium metasilicate therein, holding the glass composition at a temperature and for a time period sufficient to dissolve the lithium metasilicate therein thereby creating cristobalite nucleii, cooling the glass composition and maintaining the composition at a temperature and for a time period sufficient to recrystallize lithium metasilicate therein, and thermally treating the glass composition at a temperature and for a time period sufficient to cause growth of cristobalite and further crystallization of lithium metasilicate producing a glass ceramic composition having a specific thermal expansion coefficient and products containing said composition.

Glass ceramic-to-metal seals

Science.gov (United States)

Not Available

1982-04-19

A glass ceramic composition prepared by subjecting a glass composition comprising, by weight, 65 to 80% SiO/sub 2/, 8 to 16% Li/sub 2/O, 2 to 8% Al/sub 2/O/sub 3/, 1 to 8% K/sub 2/O, 1 to 5% P/sub 2/O/sub 5/ and 1.5 to 7% B/sub 2/O/sub 3/, to the following processing steps of heating the glass composition to a temperature sufficient to crystallize lithium metasilicate therein, holding the glass composition at a temperature and for a time period sufficient to dissolve the lithium metasilicate therein thereby creating cristobalite nucleii, cooling the glass composition and maintaining the composition at a temperature and for a time period sufficient to recrystallize lithium metasilicate therein, and thermally treating the glass composition at a temperature and for a time period sufficient to caus growth of cristobalite and further crystallization of lithium metasilicate producing a glass ceramic composition having a specific thermal expansion coefficient and products containing said composition.

Effect of binder burnout on the sealing performance of glass ceramics for solid oxide fuel cells

Science.gov (United States)

Ertugrul, Tugrul Y.; Celik, Selahattin; Mat, Mahmut D.

2013-11-01

The glass ceramics composite sealants are among few materials suitable for the solid oxide fuel cells (SOFC) due to their high operating temperatures (600 °C-850 °C). The glass ceramics chemically bond to both the metallic interconnector and the ceramic electrolyte and provide a gas tight connection. A careful and several stages manufacturing procedure is required to obtain a gas tight sealing. In this study, effects of binder burnout process on the sealing performance are investigated employing commercially available glass ceramic powders. The glass ceramic laminates are produced by mixing glass ceramic powders with the organic binders and employing a tape casting method. The laminates are sandwiched between the metallic interconnectors of an SOFC cell. The burnout and subsequent sealing quality are analyzed by measuring leakage rate and final macrostructure of sealing region. The effects of heating rate, dead weight load, solid loading, carrier gas and their flow rates are investigated. It is found that sealing quality is affected from all investigated parameters. While a slower heating rate is required for a better burnout, the mass flow rate of sweep gas must be adequate for removal of the burned gas. The leakage rate is reduced to 0.1 ml min-1 with 2 °C min-1 + 1 °C min-1 heating rate, 86.25% solid loading, 200 N dead weight load and 500 ml min-1 sweep gas flow rate.

A Novel SOFC/SOEC Sealing Glass with a Low SiO2 Content and a High Thermal Expansion Coefficient

DEFF Research Database (Denmark)

Kiebach, Wolff-Ragnar; Agersted, Karsten; Zielke, Philipp

2017-01-01

the amount of Si emission, a low Si containing sealing glass (chemical composition: 50 mol% CaO, 20 mol% ZnO, 20 mol% B2O3 and 10 mol% SiO2) was developed at DTU. In this work, the results from thermal characterization, the crystallization behavior of the glass and the long-term stability and adhesion......Solid oxide cells require seals that can function in harsh, elevated temperature environments. In addition, a low Si content can be advantageous, since Si impurities from the glass sealant can be transported to the active fuel electrode and poison the Ni-YSZ triple phase boundaries. To reduce...... behavior of the glass were studied under SOFC and SOEC relevant conditions. The glass-ceramic sealant performed well over 400 h, and no cell degradation or leakage related to the seal was found, indicating that the developed glass system is applicable for the use in SOFC/SOEC stacks....

Network structure and thermal stability study of high temperature seal glass

Science.gov (United States)

Lu, K.; Mahapatra, M. K.

2008-10-01

High temperature seal glass has stringent requirement on glass thermal stability, which is dictated by glass network structures. In this study, a SrO-La2O3-Al2O3-B2O3-SiO2 based glass system was studied using nuclear magnetic resonance, Raman spectroscopy, and x-ray diffraction for solid oxide cell application purpose. Glass structural unit neighboring environment and local ordering were evaluated. Glass network connectivity as well as silicon and boron glass former coordination were calculated for different B2O3:SiO2 ratios. Thermal stability of the borosilicate glasses was studied after thermal treatment at 850 °C. The study shows that high B2O3 content induces BO4 and SiO4 structural unit ordering, increases glass localized inhomogeneity, decreases glass network connectivity, and causes devitrification. Glass modifiers interact with either silicon- or boron-containing structural units and form different devitrified phases at different B2O3:SiO2 ratios. B2O3-free glass shows the best thermal stability among the studied compositions, remaining stable after thermal treatment for 200 h at 850 °C.

Nanoparticulate cerium dioxide and cerium dioxide-titanium dioxide composite thin films on glass by aerosol assisted chemical vapour deposition

International Nuclear Information System (INIS)

Qureshi, Uzma; Dunnill, Charles W.; Parkin, Ivan P.

2009-01-01

Two series of composite thin films were deposited on glass by aerosol assisted chemical vapour deposition (AACVD)-nanoparticulate cerium dioxide and nanoparticulate cerium dioxide embedded in a titanium dioxide matrix. The films were analysed by a range of techniques including UV-visible absorption spectroscopy, X-ray diffraction, scanning electron microscopy and energy dispersive analysis by X-rays. The AACVD prepared films showed the functional properties of photocatalysis and super-hydrophilicity. The CeO 2 nanoparticle thin films displaying photocatalysis and photo-induced hydrophilicity almost comparable to that of anatase titania.

A Ba-free sealing glass with a high CTE and excellent interface stability optimized for SOFC/SOEC stack applications

DEFF Research Database (Denmark)

Ritucci, Ilaria; Agersted, Karsten; Zielke, Philipp

2017-01-01

-mechanical properties and compositional variations are reviewed and discussed by thermal analyses and in situ XRD, in order to design and optimize the sealing profile and reduce the residual porosity. The glass after heat treatment partially devitrifies into augite and nepheline with residual glass phase of around 64...

A Novel SOFC/SOEC Sealing Glass with a Low SiO2 Content and a High Thermal Expansion Coefficient  

DEFF Research Database (Denmark)

Kiebach, Wolff-Ragnar; Agersted, Karsten; Zielke, Philipp

2017-01-01

phase boundaries. To reduce the amount of Si emission, a low Si containing sealing glass (chemical composition: 48 mol% CaO, 19 mol% ZnO, 21 mol% B2O3 and 12 mol% SiO2) was developed at DTU. In this presentation, the results from thermal characterization, like thermal expansion coefficient, glass......Solid oxide cells require seals that can function in harsh, elevated temperature environments. In the case of solid oxide electrolysis (SOEC), also a low Si content is desired, since Si impurities from the glass sealing can be transported to the active fuel electrode and poison the Ni-YSZ triple...... transition temperature, crystallization temperature, etc., of the glass will be presented. Additionally, the crystallization behavior of the glass was analyzed by in-situ X-ray diffraction, recording temperature resolved XRD spectra from 30 °C up to 900 °C. Furthermore, the long-term stability...

Interfacial reactions between titanium and borate glass

Energy Technology Data Exchange (ETDEWEB)

Brow, R.K. [Sandia National Labs., Albuquerque, NM (United States); Saha, S.K.; Goldstein, J.I. [Lehigh Univ., Bethlehem, PA (United States). Dept. of Materials Science

1992-12-31

Interfacial reactions between melts of several borate glasses and titanium have been investigated by analytical scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS). A thin titanium boride interfacial layer is detected by XPS after short (30 minutes) thermal treatments. ASEM analyses after longer thermal treatments (8--120 hours) reveal boron-rich interfacial layers and boride precipitates in the Ti side of the interface.

Glass ceramics for sealing to high-thermal-expansion metals

International Nuclear Information System (INIS)

Wilder, J.A. Jr.

1980-10-01

Glass ceramics were studied, formulated in the Na 2 O CaO.P 2 O 5 , Na 2 O.BaOP 2 O 5 , Na 2 O.Al 2 O 3 .P 2 O 5 , and Li 2 O.BaO.P 2 O 5 systems to establish their suitability for sealing to high thermal expansion metals, e.g. aluminum, copper, and 300 series stainless steels. Glass ceramics in Na 2 O.CaO.P 2 O 5 and Na 2 O.BaO.P 2 O 5 systems have coefficients of thermal expansion in the range 140 x 10 -1 per 0 C less than or equal to α less than or equal to 225 x 10 -7 per 0 C and fracture toughness values generally greater than those of phosphate glasses; they are suitable for fabricating seals to high thermal expansion metals. Crystal phases include NaPo 3 , (NaPO 3 ) 3 , NaBa(PO 3 ) 3 , and NaCa(PO 3 ) 3 . Glass ceramics formed in the Na 2 O.Al 2 O 3 .P 2 O 5 systems have coefficients of thermal expansion greater than 240 x 10 -7 per 0 C, but they have extensive microcracking. Due to their low thermal expansion values (α less than or equal to 120 x 10 -7 per 0 C), glass ceramics in the Li 2 O.BaO.P 2 O 5 system are unsuitable for sealing to high thermal expansion metals

High performance corrosion and wear resistant composite titanium nitride layers produced on the AZ91D magnesium alloy by a hybrid method

Directory of Open Access Journals (Sweden)

Michał Tacikowski

2014-09-01

Full Text Available Composite, diffusive titanium nitride layers formed on a titanium and aluminum sub-layer were produced on the AZ91D magnesium alloy. The layers were obtained using a hybrid method which combined the PVD processes with the final sealing by a hydrothermal treatment. The microstructure, resistance to corrosion, mechanical damage, and frictional wear of the layers were examined. The properties of the AZ91D alloy covered with these layers were compared with those of the untreated alloy and of some engineering materials such as 316L stainless steel, 100Cr6 bearing steel, and the AZ91D alloy subjected to commercial anodizing. It has been found that the composite diffusive nitride layer produced on the AZ91D alloy and then sealed by the hydrothermal treatment ensures the corrosion resistance comparable with that of 316L stainless steel. The layers are characterized by higher electrochemical durability which is due to the surface being overbuilt with the titanium oxides formed, as shown by the XPS examinations, from titanium nitride during the hydrothermal treatment. The composite titanium nitride layers exhibit high resistance to mechanical damage and wear, including frictional wear which is comparable with that of 100Cr6 bearing steel. The performance properties of the AZ91D magnesium alloy covered with the composite titanium nitride coating are substantially superior to those of the alloy subjected to commercial anodizing which is the dominant technique employed in industrial practice.

Self-cleaning glass coating containing titanium oxide and silicon; Revestimentos autolimpantes para vidros contendo oxido de titanio e silicio

Energy Technology Data Exchange (ETDEWEB)

Araujo, A.O. de; Alves, A.K.; Berutti, F.A.; Bergmann, C.P. [Universidade Federal do Rio Grande do Sul (LACER/UFRGS), Porto Alegre, RS (Brazil). Lab. de Materiais Ceramicos

2009-07-01

Using the electro spinning technique nano fibers of titanium oxide doped with silicon were synthesized. As precursor materials, titanium propoxide, silicon tetra propoxide and a solution of polyvinylpyrrolidone were used. The non-tissue material obtained was characterized by X-ray diffraction to determine the phase and crystallite size, BET method to determine the surface and SEM to analyze the microstructure of the fibers. After ultrasound dispersion of this material in ethanol, the glass coatings were made by dip-coating methodology. The influence of the removal velocity, the solution composition and the glass surface preparation were evaluated. The film was characterized by the contact angle of a water droplet in its surface. (author)

Mechanical verification of soft-tissue attachment on bioactive glasses and titanium implants.

Science.gov (United States)

Zhao, Desheng; Moritz, Niko; Vedel, Erik; Hupa, Leena; Aro, Hannu T

2008-07-01

Soft-tissue attachment is a desired feature of many clinical biomaterials. The aim of the current study was to design a suitable experimental method for tensile testing of implant incorporation with soft-tissues. Conical implants were made of three compositions of bioactive glass (SiO(2)-P(2)O(5)-B(2)O(3)-Na(2)O-K(2)O-CaO-MgO) or titanium fiber mesh (porosity 84.7%). The implants were surgically inserted into the dorsal subcutaneous soft-tissue or back muscles in the rat. Soft-tissue attachment was evaluated by pull-out testing using a custom-made jig 8 weeks after implantation. Titanium fiber mesh implants had developed a relatively high pull-out force in subcutaneous tissue (12.33+/-5.29 N, mean+/-SD) and also measurable attachment with muscle tissue (2.46+/-1.33 N). The bioactive glass implants failed to show mechanically relevant soft-tissue bonding. The experimental set-up of mechanical testing seems to be feasible for verification studies of soft-tissue attachment. The inexpensive small animal model is beneficial for large-scale in vivo screening of new biomaterials.

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

Science.gov (United States)

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

2017-08-01

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

Proposed Testing to Assess the Accuracy of Glass-To-Metal Seal Stress Analyses.

Energy Technology Data Exchange (ETDEWEB)

Chambers, Robert S.; Emery, John M; Tandon, Rajan; Antoun, Bonnie R.; Stavig, Mark E.; Newton, Clay S.; Gibson, Cory S; Bencoe, Denise N.

2014-09-01

The material characterization tests conducted on 304L VAR stainless steel and Schott 8061 glass have provided higher fidelity data for calibration of material models used in Glass - T o - Metal (GTM) seal analyses. Specifically, a Thermo - Multi - Linear Elastic Plastic ( thermo - MLEP) material model has be en defined for S S304L and the Simplified Potential Energy Clock nonlinear visc oelastic model has been calibrated for the S8061 glass. To assess the accuracy of finite element stress analyses of GTM seals, a suite of tests are proposed to provide data for comparison to mo del predictions.

Microstructure Effects on Spall Strength of Titanium-based Bulk Metallic Glass Composites

Science.gov (United States)

Diaz, Rene; Hofmann, Douglas; Thadhani, Naresh; Georgia Tech Team; GT-JPL Collaboration

2017-06-01

The spall strength of Ti-based metallic glass composites is investigated as a function of varying volume fractions (0-80%) of in-situ formed crystalline dendrites. With increasing dendrite content, the topology changes such that neither the harder glass nor the softer dendrites dominate the microstructure. Plate-impact experiments were performed using the 80-mm single-stage gas gun over impact stresses up to 18 GPa. VISAR interferometry was used to obtain rear free-surface velocity profiles revealing the velocity pullback spall failure signals. The spall strengths were higher than for Ti-6Al-4V alloy, and remained high up to impact stress. The influence of microstructure on the spall strength is indicated by the constants of the power law fit with the decompression strain rate. Differences in fracture behavior reveal void nucleation as a dominant mechanism affecting the spall strength. The microstructure with neither 100% glass nor with very high crystalline content, provides the most tortuous path for fracture and therefore highest spall strength. The results allow projection of spall strength predictions for design of in-situ formed metallic glass composites. ARO Grant # W911NF-09 ``1-0403 NASA JPL Contract # 1492033 ``Prime # NNN12AA01C; NSF GRFP Grant #DGE-1148903; and NDSE & G.

Self-cleaning glasses containing nanostructured titanium oxide; Vidros autolimpantes contendo oxido de titanio nanoestruturado

Energy Technology Data Exchange (ETDEWEB)

Araujo, A.; Alves, A.K.; Berutti, F.A.; Bergmann, C.P. [Universidade Federal do Rio Grande do Sul (DEMa/UFRGS), Porto Alegre, RS (Brazil). Dept. de Materiais

2010-07-01

Using the electrospinning technique nanofibers of titanium oxide were synthesized. As precursor materials, titanium propoxide and a solution of polyvinylpyrrolidone were used. After the electrospinning process, the non-tissue material obtained was heat treated and characterized by X-ray diffraction to determine the phase crystallinity, and SEM to analyze the microstructure of the fibers. After ultrasound dispersion of this material in isopropyl alcohol, the glass coatings were made by dip-coating methodology. The removal velocity was kept constant, but the solution composition was varied to obtain a transparent and photo active film. The film was characterized by the contact angle of a water droplet in its surface (hydrophilicity), the transparency was evaluated using a spectrophotometer and the photocatalytic activity of the film was also evaluated. (author)

Properties Of Soda/Yttria/Silica Glasses

Science.gov (United States)

Angel, Paul W.; Hann, Raiford E.

1994-01-01

Experimental study of glass-formation compositional region of soda/ yttria/silicate system and of selected physical properties of glasses within compositional region part of continuing effort to identify glasses with high coefficients of thermal expansion and high softening temperatures, for use as coatings on superalloys and as glass-to-metal seals.

Effects of titanium nanoparticles on self-cleaning and structural features of zinc-magnesium-phosphate glass

International Nuclear Information System (INIS)

Ismail, S.F.; Sahar, M.R.; Ghoshal, S.K.

2016-01-01

Graphical abstract: Water contact angle for sample S2, S3, S4 and S5. The water contact angle increased with increased the titanium NPs content (mol%). - Highlights: • ZnO–MgO–P_2O_5 embedded TiO_2 NPs prepared by conventional melt-quenching method. • The amorphous nature is confirmed by X-ray diffraction spectroscopy. • The structural characteristics of glasses is investigated using FTIR and Raman. • Wettability of the glasses surface by water contact angle. - Abstract: The loss of glass transparency on surface pollutants contamination unless inhibited not only causes vision obscurity but also responsible for major aesthetic damages of cultural heritage. It is due to the sticking of fine dirt particles on wetting layers, a complex process with several possible ramifications still to be clarified. We report the influence of titanium dioxide or titania (TiO_2) nanoparticles (NPs) on the structural and self-cleaning properties of zinc–magnesium–phosphate glasses. Following melt-quenching method glass samples of optimized composition (42 − x)P_2O_5–8MgO–50ZnO–xTiO_2 with x = 0, 1, 2, 3 and 4 mol% are prepared. XRD patterns verified their amorphous nature and TEM images revealed the nucleation of TiO_2 NPs of average diameter ≈4.05 ± 0.01 nm. Fourier transform infrared (FTIR) spectra displayed four absorption band centred at 1618–3438 cm"−"1, 902– 931 cm"−"1, 757–762 cm"−"1 and 531–560 cm"−"1. Raman spectra exhibited four peaks each accompanied by a blue-shift. Water contact angle is found to increase with the increase of titanium NPs concentration into the amorphous matrix. This knowledge can be used to set up strategies and selective treatments to preventing glass transparency loss via the modification of self-cleaning attributes.

Effects of titanium nanoparticles on self-cleaning and structural features of zinc-magnesium-phosphate glass

Energy Technology Data Exchange (ETDEWEB)

Ismail, S.F.; Sahar, M.R., E-mail: mrahim057@gmail.com; Ghoshal, S.K.

2016-02-15

Graphical abstract: Water contact angle for sample S2, S3, S4 and S5. The water contact angle increased with increased the titanium NPs content (mol%). - Highlights: • ZnO–MgO–P{sub 2}O{sub 5} embedded TiO{sub 2} NPs prepared by conventional melt-quenching method. • The amorphous nature is confirmed by X-ray diffraction spectroscopy. • The structural characteristics of glasses is investigated using FTIR and Raman. • Wettability of the glasses surface by water contact angle. - Abstract: The loss of glass transparency on surface pollutants contamination unless inhibited not only causes vision obscurity but also responsible for major aesthetic damages of cultural heritage. It is due to the sticking of fine dirt particles on wetting layers, a complex process with several possible ramifications still to be clarified. We report the influence of titanium dioxide or titania (TiO{sub 2}) nanoparticles (NPs) on the structural and self-cleaning properties of zinc–magnesium–phosphate glasses. Following melt-quenching method glass samples of optimized composition (42 − x)P{sub 2}O{sub 5}–8MgO–50ZnO–xTiO{sub 2} with x = 0, 1, 2, 3 and 4 mol% are prepared. XRD patterns verified their amorphous nature and TEM images revealed the nucleation of TiO{sub 2} NPs of average diameter ≈4.05 ± 0.01 nm. Fourier transform infrared (FTIR) spectra displayed four absorption band centred at 1618–3438 cm{sup −1}, 902– 931 cm{sup −1}, 757–762 cm{sup −1} and 531–560 cm{sup −1}. Raman spectra exhibited four peaks each accompanied by a blue-shift. Water contact angle is found to increase with the increase of titanium NPs concentration into the amorphous matrix. This knowledge can be used to set up strategies and selective treatments to preventing glass transparency loss via the modification of self-cleaning attributes.

Improving the chemical compatibility of sealing glass for solid oxide fuel cells: Blocking the reactive species by controlled crystallization

Science.gov (United States)

Zhang, Teng; Zou, Qi; Zeng, Fanrong; Wang, Shaorong; Tang, Dian; Yang, Hiswen

2012-10-01

The chemical compatibility of sealing glass is of great importance for Solid oxide fuel cell (SOFC). In this work, the interfacial reaction between sealing glass and Cr-containing interconnect alloy is characterized by reacting Cr2O3 powders with a representative SrO-containing glass crystallized by different heat-treatment schedules. The crystalline structure and crystalline content of sealing glass are determined by X-ray diffraction. The results show that the fraction of Cr6+ decreases from 39.8 ± 1.9% for quenched glass to 8.2 ± 0.4% for glass crystallized at 900 °C for 2 h. In addition, the interfacial reaction can be further reduced with increasing crystallization temperature and time as well as the addition of nucleation agent (TiO2). The formation of some Sr-containing crystalline phases, Sr2SiO4 and Sr(TiO3), contributes to the improvement of chemical compatibility of sealing glass, in agreement with the results of thermodynamic calculations.

Crack Growth Properties of Sealing Glasses

Science.gov (United States)

Salem, Jonathan A.; Tandon, R.

2008-01-01

The crack growth properties of several sealing glasses were measured using constant stress rate testing in 2% and 95% RH (relative humidity). Crack growth parameters measured in high humidity are systematically smaller (n and B) than those measured in low humidity, and velocities for dry environments are approx. 100x lower than for wet environments. The crack velocity is very sensitivity to small changes in RH at low RH. Confidence intervals on parameters that were estimated from propagation of errors were comparable to those from Monte Carlo simulation.

Titanium oxide nanocoating on a titanium thin film deposited on a glass substrate

Energy Technology Data Exchange (ETDEWEB)

Kotsedi, L., E-mail: kotsedi@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS, National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS, National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Eaton, S.M. [Physics Department, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano (Italy); Cummings, F.R. [University of the Western Cape, Electron Microscopy Unit, Physics Department, Bellville 7535, Cape Town (South Africa); Turco, S. Lo; Ntwaeaborwa, O.M. [Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Milano, Italy Via Giovanni Pascoli, 70/3, 20133 Milano (Italy); Ramponi, R. [Institute for Photonics and Nanotechnologies (IFN)-CNR, Piazza Leonardo Da Vinci, 32, 20133 Milano (Italy); Maaza, M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS, National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa)

2016-03-31

Thin films of titanium were deposited on a glass substrate using electron beam evaporator. Femtosecond laser pulses were focused on the surface of the films, and the samples were scanned while mounted on the motorized computer-controlled motion stage to produce an areal modification of the films. X-ray diffraction of the laser-patterned samples showed evidence of the formation of a γ-Ti{sub 3}O{sub 5} with a monoclinic phase. Rutherford backscattering spectrometry simulation showed that there is an increase in the oxygen concentration as the average laser fluence is increased. Time of flight secondary ions mass spectrometry analysis showed an even distribution of the titanium and oxygen ions on the sample and also ionized molecules of the oxides of titanium were observed. The formation of the oxide of titanium was further supported using the UV–Vis-NIR spectroscopy, which showed that for 0.1 J/cm{sup 2} fluence, the laser-exposed film showed the electron transfer band and the d–d transition peak of titanium was observed at lower wavelengths. - Highlights: • γ-Ti{sub 3}O{sub 5} formed using femtosecond laser. • Fluence and oxygen relation were studied. • Nanoflakes of γ-Ti{sub 3}O{sub 5} were observed under HRSEM.

Structure, phases, and mechanical response of Ti-alloy bioactive glass composite coatings

Energy Technology Data Exchange (ETDEWEB)

Nelson, G.M.; Nychka, J.A. [Department of Chemical and Materials Engineering, University of Alberta, 7th Floor, Electrical and Computer Engineering Research Facility, Edmonton, Alberta T6G 2V4 (Canada); McDonald, A.G., E-mail: andre2@ualberta.ca [Department of Mechanical Engineering, University of Alberta, 4-9 Mechanical Engineering Building, Edmonton, Alberta T6G 2G8 (Canada)

2014-03-01

Porous titanium alloy-bioactive glass composite coatings were manufactured via the flame spray deposition process. The porous coatings, targeted for orthodontic and bone-fixation applications, were made from bioactive glass (45S5) powder blended with either commercially pure titanium (Cp-Ti) or Ti-6Al-4V alloy powder. Two sets of spray conditions, two metallic particle size distributions, and two glass particle size distributions were used for this study. Negative control coatings consisting of pure Ti-6Al-4V alloy or Cp-Ti were sprayed under both conditions. The as-sprayed coatings were characterized through quantitative optical cross-sectional metallography, X-ray diffraction (XRD), and ASTM Standard C633 tensile adhesion testing. Determination of the porosity and glassy phase distribution was achieved by using image analysis in accordance with ASTM Standard E2109. Theoretical thermodynamic and heat transfer modeling was conducted to explain experimental observations. Thermodynamic modeling was performed to estimate the flame temperature and chemical environment for each spray condition and a lumped capacitance heat transfer model was developed to estimate the temperatures attained by each particle. These models were used to establish trends among the choice of alloy, spray condition, and particle size distribution. The deposition parameters, alloy composition, and alteration of the feedstock powder size distribution had a significant effect on the coating microstructure, porosity, phases present, mechanical response, and theoretical particle temperatures that were attained. The most promising coatings were the Ti-6Al-4V-based composite coatings, which had bond strength of 20 ± 2 MPa (n = 5) and received reinforcement and strengthening from the inclusion of a glassy phase. It was shown that the use of the Ti-6Al-4V-bioactive glass composite coatings may be a superior choice due to the possible osteoproductivity from the bioactive glass, the potential ability to

Window Spacers and Edge Seals in Insulating Glass Units: A State-of-the-Art Review and Future Perspectives

Energy Technology Data Exchange (ETDEWEB)

SINTEF Building and Infrastructure; Norwegian University of Science and Technology (NTNU); Bergh, Sofie Van Den; Hart, Robert; Jelle, Bjrn Petter; Gustavsen, Arild

2013-01-31

Insulating glass (IG) units typically consist of multiple glass panes that are sealed and held together structurally along their perimeters. This report describes a study of edge seals in IG units. First, we summarize the components, requirements, and desired properties of edge construction in IG units, based on a survey of the available literature. Second, we review commercially available window edge seals and describe their properties, to provide an easily accessible reference for research and commercial purposes. Finally, based on the literature survey and review of current commercial edge seal systems, we identify research opportunities for future edge seal improvements and solutions.

Effect of aluminizing of Cr-containing ferritic alloys on the seal strength of a novel high-temperature solid oxide fuel cell sealing glass

Science.gov (United States)

Chou, Yeong-Shyung; Stevenson, Jeffry W.; Singh, Prabhakar

A novel high-temperature alkaline earth silicate sealing glass was developed for solid oxide fuel cell (SOFC) applications. The glass was used to join two metallic coupons of Cr-containing ferritic stainless steel for seal strength evaluation. In previous work, SrCrO 4 was found to form along the glass/steel interface, which led to severe strength degradation. In the present study, aluminization of the steel surface was investigated as a remedy to minimize or prevent the strontium chromate formation. Three different processes for aluminization were evaluated with Crofer22APU stainless steel: pack cementation, vapor-phase deposition, and aerosol spraying. It was found that pack cementation resulted in a rough surface with occasional cracks in the Al-diffused region. Vapor-phase deposition yielded a smoother surface, but the resulting high Al content increased the coefficient of thermal expansion (CTE), resulting in the failure of joined coupons. Aerosol spraying of an Al-containing salt resulted in the formation of a thin aluminum oxide layer without any surface damage. The room temperature seal strength was evaluated in the as-fired state and in environmentally aged conditions. In contrast to earlier results with uncoated Crofer22APU, the aluminized samples showed no strength degradation even for samples aged in air. Interfacial and chemical compatibility was also investigated. The results showed aluminization to be a viable candidate approach to minimize undesirable chromate formation between alkaline earth silicate sealing glass and Cr-containing interconnect alloys for SOFC applications.

[Comparative studies on fissure sealing: composite versus Cermet cement].

Science.gov (United States)

Hickel, R; Voss, A

1989-06-01

Fifty two molars sealed with either composite or Cermet cement were compared. The composite sealant was applied after enamel etching using a rubber dam. Before sealing with Cermet cement the enamel was only cleaned with pumice powder and sodium hypochlorie and the material was applied without enamel etching. After an average follow-up of 1.6 years composite sealants proved to be significantly more reliable. Cermet cement sealings showed defects more frequently.

Process for making a titanium diboride-chromium diboride-yttrium titanium oxide ceramic composition

Science.gov (United States)

Holcombe, C.E.; Dykes, N.L.

1992-04-28

A ceramic composition is described. The ceramic composition consists essentially of from about 84 to 96 w/o titanium diboride, from about 1 to 9 w/o chromium diboride, and from about 3 to about 15 w/o yttrium-titanium-oxide. A method of making the ceramic composition is also described. The method of making the ceramic composition comprises the following steps: Step 1--A consolidated body containing stoichiometric quantities of titanium diboride and chromium diboride is provided. Step 2--The consolidated body is enclosed in and in contact with a thermally insulated package of yttria granules having a thickness of at least 0.5 inches. Step 3--The consolidated body enclosed in the thermally insulated package of yttria granules is heated in a microwave oven with microwave energy to a temperature equal to or greater than 1,900 degrees centigrade to sinter and uniformly disperse yttria particles having a size range from about 1 to about 12 microns throughout the consolidated body forming a densified body consisting essentially of titanium diboride, chromium diboride, and yttrium-titanium-oxide. The resulting densified body has enhanced fracture toughness and hardness. No Drawings

Microstructure and mechanical properties of low-activation glass-ceramic joining and coating for SiC/SiC composites

International Nuclear Information System (INIS)

Katoh, Yutai; Kotani, M.; Kohyama, A.; Montorsi, M.; Salvo, M.; Ferraris, M.

2000-01-01

Calcia-alumina (CA) glass-ceramic was studied as a candidate low-activation joining and sealing material for SiC/SiC components for fusion blanket and diverter structures, in terms of microstructural stability and mechanical properties. The CA glass-ceramic joining and seal coating were applied to the Hi-Nicalon TM SiC fiber-reinforced SiC matrix composites in which the matrix had been formed through chemical vapor infiltration and polymer impregnation and pyrolysis methods. Microstructural characterization was carried out for the joined and coated materials by optical and scanning electron microscopy (SEM). The mechanical property of the joint was evaluated through a shear test on sandwich joints. The average shear strength of the joined structures was 28 MPa at room temperature. Fractography revealed that the fracture occurred in the glass phase and the shear strength may be improved by reduction of the glass fraction

Controlling the reaction between boron-containing sealing glass and a lanthanum-containing cathode by adding Nb2O5

Science.gov (United States)

Zhao, Dandan; Fang, Lihua; Tang, Dian; Zhang, Teng

2016-09-01

In solid oxide fuel cell (SOFC) stacks, the volatile boron species present in the sealing glass often react with the lanthanum-containing cathode, degrading the activity of the cathode (this phenomenon is known as boron poisoning). In this work, we report that this detrimental reaction can be effectively reduced by doping bismuth-containing borosilicate sealing glass-ceramic with a niobium dopant. The addition of Nb2O5 not only condenses the [SiO4] structural units in the glass network, but also promotes the conversion of [BO3] to [BO4]. Moreover, the Nb2O5 dopant enhances the formation of boron-containing phases (Ca3B2O6 and CaB2Si2O8), which significantly reduces the volatility of boron compounds in the sealing glass, suppressing the formation of LaBO3 in the reaction couple between the glass and the cathode. The reported results provide a new approach to solve the problem of boron poisoning.

Fabrication and sealing performance of rare-earth containing glass–ceramic seals for intermediate temperature solid oxide fuel cell applications

DEFF Research Database (Denmark)

Abdoli, H.; Alizadeh, P.; Agersted, Karsten

2014-01-01

The opportunity of using two rare-earth metal oxides in an aluminosilicate glass for seal applications was investigated in this work. Substitution of La2O3 with Y2O3 in the system changed thermal and physical properties such as transition temperature, flowing behavior, and thermal expansion....... The strongly bound structural unit in the network affected glass healing capability with a slower healing response. Higher activation energy (≥20%) was required for Y2O3 containing glass, consistent with in-situ XRD results which revealed its amorphous nature is maintained ~75°C above the other glass. Despite...... containing strontium in the composition, well bonded interface was obtained in contact with 8YSZ and SS430 ferritic stainless steel. The hermeticity of the glass seals was maintained after 100h isothermal aging at 800°C. Also the OCV showed insignificant fluctuations with stable average values after 24...

Titanium reinforced boron-polyimide composite

Science.gov (United States)

Clark, G. A.; Clayton, K. I.

1969-01-01

Processing techniques for boron polyimide prepreg were developed whereby composites could be molded under vacuum bag pressure only. A post-cure cycle was developed which resulted in no loss in room temperature mechanical properties of the composite at any time during up to 16 hours at 650 F. A design utilizing laminated titanium foil was developed to achieve a smooth transition of load from the titanium attachment points into the boron-reinforced body of the structure. The box beam test article was subjected to combined bending and torsional loads while exposed to 650 F. Loads were applied incrementally until failure occurred at 83% design limit load.

Glass-Graphite Composite Materials

International Nuclear Information System (INIS)

Mayzan, M.Z.H.; Lloyd, J.W.; Heath, P.G.; Stennett, M.C.; Hyatt, N.C.; Hand, R.J.

2016-01-01

A summary is presented of investigations into the potential of producing glass-composite materials for the immobilisation of graphite or other carbonaceous materials arising from nuclear power generation. The methods are primarily based on the production of base glasses which are subsequently sintered with powdered graphite or simulant TRISO particles. Consideration is also given to the direct preparation of glass-graphite composite materials using microwave technology. Production of dense composite wasteforms with TRISO particles was more successful than with powdered graphite, as wasteforms containing larger amounts of graphite were resistant to densification and the glasses tried did not penetrate the pores under the pressureless conditions used. Based on the results obtained it is concluded that the production of dense glassgraphite composite wasteforms will require the application of pressure. (author)

Sealing materials for solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Larsen, P.H.

1999-02-01

A major obstacle in the achievement of high electrical efficiency for planar solid oxide fuel cell stacks (SOFC) is the need for long term stable seals at the operational temperature between 850 and 1000 deg. C. In the present work the formation and properties of sealing materials for SOFC stacks that fulfil the necessary requirements were investigated. The work comprises analysis of sealing material properties independently, in simple systems as well as tests in real SOFC stacks. The analysed sealing materials were based on pure glasses or glass-ceramic composites having B{sub 2}O{sub 3}, P{sub 2}O{sub 5} or siO{sub 2} as glass formers, and the following four glass systems were investigated: MgO/caO/Cr{sub 2}O{sub 3}-Al{sub 2}O{sub 3}B{sub 2}O{sub 3}-P{sub 2}O{sub 5}, MgO-Al{sub 2}O{sub 3}-P{sub 2}O{sub 5}, MgO-Al{sub 2}O{sub 3}-P{sub 2}O{sub 5}-SiO{sub 2} and BaO/Na{sub 2}O-Al{sub 2}O{sub 3}-SiO{sub 2}. (au) 32 tabs., 106 ills., 107 refs.

Laser cladding of bioactive glass coatings.

Science.gov (United States)

Comesaña, R; Quintero, F; Lusquiños, F; Pascual, M J; Boutinguiza, M; Durán, A; Pou, J

2010-03-01

Laser cladding by powder injection has been used to produce bioactive glass coatings on titanium alloy (Ti6Al4V) substrates. Bioactive glass compositions alternative to 45S5 Bioglass were demonstrated to exhibit a gradual wetting angle-temperature evolution and therefore a more homogeneous deposition of the coating over the substrate was achieved. Among the different compositions studied, the S520 bioactive glass showed smoother wetting angle-temperature behavior and was successfully used as precursor material to produce bioactive coatings. Coatings processed using a Nd:YAG laser presented calcium silicate crystallization at the surface, with a uniform composition along the coating cross-section, and no significant dilution of the titanium alloy was observed. These coatings maintain similar bioactivity to that of the precursor material as demonstrated by immersion in simulated body fluid. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Bulk metallic glass matrix composites

International Nuclear Information System (INIS)

Choi-Yim, H.; Johnson, W.L.

1997-01-01

Composites with a bulk metallic glass matrix were synthesized and characterized. This was made possible by the recent development of bulk metallic glasses that exhibit high resistance to crystallization in the undercooled liquid state. In this letter, experimental methods for processing metallic glass composites are introduced. Three different bulk metallic glass forming alloys were used as the matrix materials. Both ceramics and metals were introduced as reinforcement into the metallic glass. The metallic glass matrix remained amorphous after adding up to a 30 vol% fraction of particles or short wires. X-ray diffraction patterns of the composites show only peaks from the second phase particles superimposed on the broad diffuse maxima from the amorphous phase. Optical micrographs reveal uniformly distributed particles in the matrix. The glass transition of the amorphous matrix and the crystallization behavior of the composites were studied by calorimetric methods. copyright 1997 American Institute of Physics

Trial manufacturing of titanium-carbon steel composite overpack

International Nuclear Information System (INIS)

Honma, Nobuyuki; Chiba, Takahiko; Tanai, Kenji

1999-11-01

This paper reports the results of design analysis and trial manufacturing of full-scale titanium-carbon steel composite overpacks. The overpack is one of the key components of the engineered barrier system, hence, it is necessary to confirm the applicability of current technique in their manufacture. The required thickness was calculated according to mechanical resistance analysis, based on models used in current nuclear facilities. The Adequacy of the calculated dimensions was confirmed by finite-element methods. To investigate the necessity of a radiation shielding function of the overpack, the irradiation from vitrified waste has been calculated. As a result, it was shown that shielding on handling and transport equipment is a more reasonable and practical approach than to increase thickness of overpack to attain a self-shielding capability. After the above investigation, trial manufacturing of full-scale model of titanium-carbon steel composite overpack has been carried out. For corrosion-resistant material, ASTM Grade-2 titanium was selected. The titanium layer was bonded individually to a cylindrical shell and fiat cover plates (top and bottom) made of carbon steel. For the cylindrical shell portion, a cylindrically formed titanium layer was fitted to the inner carbon steel vessel by shrinkage. For the flat cover plates (top and bottom), titanium plate material was coated by explosive bonding. Electron beam welding and gas metal arc welding were combined to weld of the cover plates to the body. No significant failure was evident from inspections of the fabrication process, and the applicability of current technology for manufacturing titanium-carbon steel composite overpack was confirmed. Future research and development items regarding titanium-carbon steel composite overpacks are also discussed. (author)

Using physical properties of molten glass to estimate glass composition

International Nuclear Information System (INIS)

Choi, Kwan Sik; Yang, Kyoung Hwa; Park, Jong Kil

1997-01-01

A vitrification process is under development in KEPRI for the treatment of low-and medium-level radioactive waste. Although the project is for developing and building Vitrification Pilot Plant in Korea, one of KEPRI's concerns is the quality control of the vitrified glass. This paper discusses a methodology for the estimation of glass composition by on-line measurement of molten glass properties, which could be applied to the plant for real-time quality control of the glass product. By remotely measuring viscosity and density of the molten glass, the glass characteristics such as composition can be estimated and eventually controlled. For this purpose, using the database of glass composition vs. physical properties in isothermal three-component system of SiO 2 -Na 2 O-B 2 O 3 , a software TERNARY has been developed which determines the glass composition by using two known physical properties (e.g. density and viscosity)

Magnetic nanofluids and magnetic composite fluids in rotating seal systems

International Nuclear Information System (INIS)

Borbath, T; Borbath, I; Boros, T; Bica, D; Vekas, L; Potencz, I

2010-01-01

Recent results are presented concerning the development of magnetofluidic leakage-free rotating seals for vacuum and high pressure gases, evidencing significant advantages compared to mechanical seals. The micro-pilot scale production of various types of magnetizable sealing fluids is shortly reviewed, in particular the main steps of the chemical synthesis of magnetic nanofluids and magnetic composite fluids with light hydrocarbon, mineral oil and synthetic oil carrier liquids. The behavior of different types of magnetizable fluids in the rotating sealing systems is analyzed. Design concepts, some constructive details and testing procedures of magnetofluidic rotating seals are presented such as the testing equipment. The main characteristics of several magnetofluidic sealing systems and their applications will be presented: vacuum deposition systems and liquefied gas pumps applications, mechanical and magnetic nanofluid combined seals, gas valves up to 40 bar equipped by rotating seal with magnetic nanofluids and magnetic composite fluids.

Database for waste glass composition and properties

International Nuclear Information System (INIS)

Peters, R.D.; Chapman, C.C.; Mendel, J.E.; Williams, C.G.

1993-09-01

A database of waste glass composition and properties, called PNL Waste Glass Database, has been developed. The source of data is published literature and files from projects funded by the US Department of Energy. The glass data have been organized into categories and corresponding data files have been prepared. These categories are glass chemical composition, thermal properties, leaching data, waste composition, glass radionuclide composition and crystallinity data. The data files are compatible with commercial database software. Glass compositions are linked to properties across the various files using a unique glass code. Programs have been written in database software language to permit searches and retrievals of data. The database provides easy access to the vast quantities of glass compositions and properties that have been studied. It will be a tool for researchers and others investigating vitrification and glass waste forms

The effect of titanium surface treatment on the interfacial strength of titanium – Thermoplastic composite joints

NARCIS (Netherlands)

Su, Yibo; de Rooij, Matthijn; Grouve, Wouter; Akkerman, Remko

2017-01-01

Co-consolidated titanium – carbon fibre reinforced thermoplastic composite hybrid joints show potential for application in aerospace structures. The strength of the interface between the titanium and the thermoplastic composite is crucial for the strength of the entire hybrid joint. Application of a

Titanium Matrix Composite Pressure Vessel, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — For over 15 years, FMW Composite Systems has developed Metal Matrix Composite manufacturing methodologies for fabricating silicon-carbide-fiber-reinforced titanium...

A simple method for tuning the glass transition process in inorganic phosphate glasses

Science.gov (United States)

Fulchiron, René; Belyamani, Imane; Otaigbe, Joshua U.; Bounor-Legaré, Véronique

2015-02-01

The physical modification of glass transition temperature (Tg) and properties of materials via blending is a common practice in industry and academia and has a large economic advantage. In this context, simple production of hitherto unattainable new inorganic glass blends from already existing glass compositions via blending raises much hope with the potential to provide new glasses with new and improved properties, that cannot be achieved with classical glass synthesis, for a plethora of applications such as computers screens, glass-to-metal seals, and storage materials for nuclear wastes. Here, we demonstrate that blends of the specific glass compositions studied are miscible in all proportions, an unreported phenomenon in hard condensed matter like glass. Interestingly, excellent agreement was found between the obtained data and calculated Tgs from theoretical equations (Supplementary information) for predicting the composition dependence of Tg for miscible blends with weak but significant specific interactions between the blend components. That this blending method is at present not applied to inorganic glasses reflects the fact that water and chemically resistant phosphate glasses with relatively low Tgs have become available only recently.

Nickel and titanium nanoboride composite coating

International Nuclear Information System (INIS)

Efimova, K A; Galevsky, G V; Rudneva, V V; Kozyrev, N A; Orshanskaya, E G

2015-01-01

Electrodeposition conditions, structural-physical and mechanical properties (microhardness, cohesion with a base, wear resistance, corrosion currents) of electroplated composite coatings on the base of nickel with nano and micro-powders of titanium boride are investigated. It has been found out that electro-crystallization of nickel with boride nanoparticles is the cause of coating formation with structural fragments of small sizes, low porosity and improved physical and mechanical properties. Titanium nano-boride is a component of composite coating, as well as an effective modifier of nickel matrix. Nano-boride of the electrolyte improves efficiency of the latter due to increased permissible upper limit of the cathodic current density. (paper)

Microstructure characteristics of vacuum glazing brazing joints using laser sealing technique

Science.gov (United States)

Liu, Sixing; Yang, Zheng; Zhang, Jianfeng; Zhang, Shanwen; Miao, Hong; Zhang, Yanjun; Zhang, Qi

2018-05-01

Two pieces of plate glass were brazed into a composite of glazing with a vacuum chamber using PbO-TiO2-SiO2-RxOy powder filler alloys to develop a new type of vacuum glazing. The brazing process was carried out by laser technology. The interface characteristics of laser brazed joints formed between plate glass and solder were investigated using optical microscope, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) techniques. The results show that the inter-diffusion of Pb/Ti/Si/O elements from the sealing solder toward the glass and O/Al/Si elements from the glass toward the solder, resulting in a reaction layer in the brazed joints. The microstructure phases of PbTiO3, AlSiO, SiO2 and PbO in the glass/solder interface were confirmed by XRD analysis. The joining of the sealing solder to the glass was realized by the reaction products like fibrous structures on interface, where the wetting layer can help improve the bonding performance and strength between the sealing solder and the plate glass during the laser brazing process.

Spark plasma sintering of titanium aluminide intermetallics and its composites

Science.gov (United States)

Aldoshan, Abdelhakim Ahmed

Titanium aluminide intermetallics are a distinct class of engineering materials having unique properties over conventional titanium alloys. gamma-TiAl compound possesses competitive physical and mechanical properties at elevated temperature applications compared to Ni-based superalloys. gamma-TiAl composite materials exhibit high melting point, low density, high strength and excellent corrosion resistance. Spark plasma sintering (SPS) is one of the powder metallurgy techniques where powder mixture undergoes simultaneous application of uniaxial pressure and pulsed direct current. Unlike other sintering techniques such as hot iso-static pressing and hot pressing, SPS compacts the materials in shorter time (< 10 min) with a lower temperature and leads to highly dense products. Reactive synthesis of titanium aluminide intermetallics is carried out using SPS. Reactive sintering takes place between liquid aluminum and solid titanium. In this work, reactive sintering through SPS was used to fabricate fully densified gamma-TiAl and titanium aluminide composites starting from elemental powders at different sintering temperatures. It was observed that sintering temperature played significant role in the densification of titanium aluminide composites. gamma-TiAl was the predominate phase at different temperatures. The effect of increasing sintering temperature on microhardness, microstructure, yield strength and wear behavior of titanium aluminide was studied. Addition of graphene nanoplatelets to titanium aluminide matrix resulted in change in microhardness. In Ti-Al-graphene composites, a noticeable decrease in coefficient of friction was observed due to the influence of self-lubrication caused by graphene.

Identifying glass compositions in fly ash

Directory of Open Access Journals (Sweden)

Katherine eAughenbaugh

2016-01-01

Full Text Available In this study, four Class F fly ashes were studied with a scanning electron microscope; the glassy phases were identified and their compositions quantified using point compositional analysis with k-means clustering and multispectral image analysis. The results showed that while the bulk oxide contents of the fly ashes were different, the four fly ashes had somewhat similar glassy phase compositions. Aluminosilicate glasses (AS, calcium aluminosilicate glasses (CAS, a mixed glass, and, in one case, a high iron glass were identified in the fly ashes. Quartz and iron crystalline phases were identified in each fly ash as well. The compositions of the three main glasses identified, AS, CAS, and mixed glass, were relatively similar in each ash. The amounts of each glass were varied by fly ash, with the highest calcium fly ash containing the most of calcium-containing glass. Some of the glasses were identified as intermixed in individual particles, particularly the calcium-containing glasses. Finally, the smallest particles in the fly ashes, with the most surface area available to react in alkaline solution, such as when mixed with portland cement or in alkali-activated fly ash, were not different in composition than the large particles, with each of the glasses represented. The method used in the study may be applied to a fly ash of interest for use as a cementing material in order to understand its potential for reactivity.

Optical absorption and fluorescent behaviour of titanium ions in ...

Indian Academy of Sciences (India)

Unknown

Titanium in normal melting conditions in air atmosphere present as Ti4+ ion in basic silicate ... exchange of electrons in between M → L → M coopera- ... glass even for higher concentration of titania than 0⋅1% ... glass composition originates from different points of .... The development of photosensitive copper ruby, silver.

Enhancing the soft tissue seal around intraosseous transcutaneous amputation prostheses using silanized fibronectin titanium alloy

Energy Technology Data Exchange (ETDEWEB)

Chimutengwende-Gordon, M; Pendegrass, C; Blunn, G, E-mail: mukai.cg@mac.com [Centre for Biomedical Engineering, Institute of Orthopaedics and Musculoskeletal Science, University College London, Brockley Hill, Stanmore, HA7 4LP (United Kingdom)

2011-04-15

The success of intraosseous transcutaneous amputation prostheses (ITAP) relies on achieving a tight seal between the soft tissues and the implant in order to avoid infection. Fibronectin (Fn) may be silanized onto titanium alloy (Ti-6Al-4V) in order to promote soft-tissue attachment. The silanization process includes passivation with sulphuric acid, which alters surface characteristics. This study aimed to improve in vitro fibroblast adhesion to silanized fibronectin (SiFn) titanium alloy by omitting the passivation stage. Additionally, the study assessed the effects of SiFn on in vivo dermal attachment, comparing the results with adsorbed Fn, hydroxyapatite (HA), Fn adsorbed onto HA (HAFn) and uncoated controls. Surface topography was assessed using scanning electron microscopy, profilometry and contact angle measurement. Anti-vinculin antibodies were used to immunolocalize fibroblast adhesion sites. A histological assessment of soft-tissue attachment and cell alignment relative to implants in an in vivo ovine model was performed. Passivation resulted in rougher, more hydrophobic, microcracked surfaces and was associated with poorer fibroblast adhesion than unpassivated controls. SiFn and HAFn surfaces resulted in more favourable cell alignment in vivo, implying that dermal attachment was enhanced. These results suggest that SiFn and HAFn surfaces could be useful in optimizing the soft tissue seal around ITAP.

Carbon Dioxide Sealing Capacity: Textural or Compositional Controls?

Energy Technology Data Exchange (ETDEWEB)

Cranganu, Constantin; Soleymani, Hamidreza; Sadiqua, Soleymani; Watson, Kieva

2013-11-30

This research project is aiming to assess the carbon dioxide sealing capacity of most common seal-rocks, such as shales and non-fractured limestones, by analyzing the role of textural and compositional parameters of those rocks. We hypothesize that sealing capacity is controlled by textural and/or compositional pa-rameters of caprocks. In this research, we seek to evaluate the importance of textural and compositional parameters affecting the sealing capacity of caprocks. The conceptu-al framework involves two testable end-member hypotheses concerning the sealing ca-pacity of carbon dioxide reservoir caprocks. Better understanding of the elements controlling sealing quality will advance our knowledge regarding the sealing capacity of shales and carbonates. Due to relatively low permeability, shale and non-fractured carbonate units are considered relatively imper-meable formations which can retard reservoir fluid flow by forming high capillary pres-sure. Similarly, these unites can constitute reliable seals for carbon dioxide capture and sequestration purposes. This project is a part of the comprehensive project with the final aim of studying the caprock sealing properties and the relationship between microscopic and macroscopic characteristics of seal rocks in depleted gas fields of Oklahoma Pan-handle. Through this study we examined various seal rock characteristics to infer about their respective effects on sealing capacity in special case of replacing reservoir fluid with super critical carbon dioxide (scCO{sub 2}). To assess the effect of textural and compositional properties on scCO{sub 2} maximum reten-tion column height we collected 30 representative core samples in caprock formations in three counties (Cimarron, Texas, Beaver) in Oklahoma Panhandle. Core samples were collected from various seal formations (e.g., Cherokee, Keys, Morrowan) at different depths. We studied the compositional and textural properties of the core samples using several techniques

A Novel Technique for the Connection of Ceramic and Titanium Implant Components Using Glass Solder Bonding

Directory of Open Access Journals (Sweden)

Enrico Mick

2015-07-01

Full Text Available Both titanium and ceramic materials provide specific advantages in dental implant technology. However, some problems, like hypersensitivity reactions, corrosion and mechanical failure, have been reported. Therefore, the combining of both materials to take advantage of their pros, while eliminating their respective cons, would be desirable. Hence, we introduced a new technique to bond titanium and ceramic materials by means of a silica-based glass ceramic solder. Cylindrical compound samples (Ø10 mm × 56 mm made of alumina toughened zirconia (ATZ, as well as titanium grade 5, were bonded by glass solder on their end faces. As a control, a two-component adhesive glue was utilized. The samples were investigated without further treatment, after 30 and 90 days of storage in distilled water at room temperature, and after aging. All samples were subjected to quasi-static four-point-bending tests. We found that the glass solder bonding provided significantly higher bending strength than adhesive glue bonding. In contrast to the glued samples, the bending strength of the soldered samples remained unaltered by the storage and aging treatments. Scanning electron microscopy (SEM and energy-dispersive X-ray (EDX analyses confirmed the presence of a stable solder-ceramic interface. Therefore, the glass solder technique represents a promising method for optimizing dental and orthopedic implant bondings.

Photoluminescence properties of Er{sup 3+}-doped alkaline earth titanium phosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Murthy, D.V.R.; Babu, A. Mohan [Department of Physics, Sri Venkateswara University, Tirupati 517 502 (India); Jamalaiah, B.C. [Department of Physics, Sree Vidyanikethan Engineering College, Tirupati, 517 102 (India); Moorthy, L. Rama, E-mail: lrmphysics@yahoo.co.i [Department of Physics, Sri Venkateswara University, Tirupati 517 502 (India); Jayasimhadri, M.; Jang, Kiwan; Lee, Ho Sueb [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Yi, Soung Soo [Department of Photonics, Silla University, Pusan 617-736 (Korea, Republic of); Jeong, Jung Hyun [Department of Physics, Pukyong National University, Pusan 608-737 (Korea, Republic of)

2010-02-18

Er{sup 3+}-doped alkaline earth titanium phosphate (RTP) glasses with molar composition of 24 (NaPO{sub 3}){sub 6} + 30 KH{sub 2}PO{sub 4} + 25 TiO{sub 2} + 20 RCl{sub 2} + 1 Er{sub 2}O{sub 3} were prepared by melt quenching technique. Judd-Ofelt intensity parameters ({Omega}{sub 2,4,6}) were determined from the experimental oscillator strengths (f{sub exp}) of absorption bands. From these parameters spontaneous emission probabilities (A{sub R}), luminescence branching ratios ({beta}{sub R}) and radiative lifetimes ({tau}{sub R}) have been calculated. Visible and near infrared photoluminescence spectra has been recorded by exciting the samples at 380 and 970 nm respectively. An intense broad emission band at 1.53 {mu}m was observed corresponding to {sup 4}I{sub 13/2} {yields} {sup 4}I{sub 15/2} transition. McCumber theory has been applied to determine the emission cross-sections ({sigma}{sub e}) of the {sup 4}I{sub 13/2} {yields} {sup 4}I{sub 15/2} transition using the absorption cross-sections ({sigma}{sub a}). The lifetimes of {sup 4}S{sub 3/2} level were measured for the glasses by exciting the samples at 540 nm wavelength and the quantum efficiencies were also determined.

Compositional threshold for Nuclear Waste Glass Durability

International Nuclear Information System (INIS)

Kruger, Albert A.; Farooqi, Rahmatullah; Hrma, Pavel R.

2013-01-01

Within the composition space of glasses, a distinct threshold appears to exist that separates 'good' glasses, i.e., those which are sufficiently durable, from 'bad' glasses of a low durability. The objective of our research is to clarify the origin of this threshold by exploring the relationship between glass composition, glass structure and chemical durability around the threshold region

Thermal conductivity of glass copper-composite

International Nuclear Information System (INIS)

Kinoshita, Makoto; Terai, Ryohei; Haidai, Haruki

1980-01-01

Glass-metal composites are to be one of the answers for promoting thermal conduction in the glassy solids containing high-level radioactive wastes. In order to investigate the effect of metal addition on thermal conductivity of glasses, glass-copper composites were selected, and the conductivities of the composites were measured and discussed in regards to copper content and microstructure. Fully densified composites were successfully prepared by pressure sintering of the powder mixtures of glass and copper at temperatures above the yield points of the constituent glasses if the copper content was not so much. The conductivity was measured by means of a comparative method, in which the thermal gradient of the specimen was compared with that of quartz glass as standard under thermally steady state. Measurements were carried out at around 50 0 C. The thermal conductivity increased with increasing content of copper depending on the kind of copper powder used. The conductivities of the composites of the same copper content differed considerably each another. Fine copper powder was effective on increasing conductivity, and the conductivity became about threefold of that of glass by mixing the fine copper powder about 10 vol%. For the composites containing the fine copper powder less than 5 vol%, the conductivity obeyed so-called logarithmic rule, one of the mixture rules of conductivity, whereas for composites containing more than 5 vol%, the conductivity remarkably increased apart from the rule. This fact suggests that copper becomes continuous in the composite when the copper content increased beyond 5 vol%. For the composites containing coarse copper powder, the conductivity was increased not significantly, and obeyed an equation derived from the model in which conductive material dispersed in less conductive one. (author)

Titanium addition influences antibacterial activity of bioactive glass coatings on metallic implants.

Science.gov (United States)

Rodriguez, Omar; Stone, Wendy; Schemitsch, Emil H; Zalzal, Paul; Waldman, Stephen; Papini, Marcello; Towler, Mark R

2017-10-01

In an attempt to combat the possibility of bacterial infection and insufficient bone growth around metallic, surgical implants, bioactive glasses may be employed as coatings. In this work, silica-based and borate-based glass series were synthesized for this purpose and subsequently characterized in terms of antibacterial behavior, solubility and cytotoxicity. Borate-based glasses were found to exhibit significantly superior antibacterial properties and increased solubility compared to their silica-based counterparts, with BRT0 and BRT3 (borate-based glasses with 0 and 15 mol% of titanium dioxide incorporated, respectively) outperforming the remainder of the glasses, both borate and silicate based, in these respects. Atomic Absorption Spectroscopy confirmed the release of zinc ions (Zn 2+ ), which has been linked to the antibacterial abilities of glasses SRT0, BRT0 and BRT3, with inhibition effectively achieved at concentrations lower than 0.7 ppm. In vitro cytotoxicity studies using MC3T3-E1 osteoblasts confirmed that cell proliferation was affected by all glasses in this study, with decreased proliferation attributed to a faster release of sodium ions over calcium ions in both glass series, factor known to slow cell proliferation in vitro .

Friction and wear performance of diamond-like carbon, boron carbide, and titanium carbide coatings against glass

International Nuclear Information System (INIS)

Daniels, B.K.; Brown, D.W.; Kimock, F.M.

1997-01-01

Protection of glass substrates by direct ion beam deposited diamond-like carbon (DLC) coatings was observed using a commercial pin-on-disk instrument at ambient conditions without lubrication. Ion beam sputter-deposited titanium carbide and boron carbide coatings reduced sliding friction, and provided tribological protection of silicon substrates, but the improvement factor was less than that found for DLC. Observations of unlubricated sliding of hemispherical glass pins at ambient conditions on uncoated glass and silicon substrates, and ion beam deposited coatings showed decreased wear in the order: uncoated glass>uncoated silicon>boron carbide>titanium carbide>DLC>uncoated sapphire. Failure mechanisms varied widely and are discussed. Generally, the amount of wear decreased as the sliding friction decreased, with the exception of uncoated sapphire substrates, for which the wear was low despite very high friction. There is clear evidence that DLC coatings continue to protect the underlying substrate long after the damage first penetrates through the coating. The test results correlate with field use data on commercial products which have shown that the DLC coatings provide substantial extension of the useful lifetime of glass and other substrates. copyright 1997 Materials Research Society

Formation of an ascorbate-apatite composite layer on titanium

Energy Technology Data Exchange (ETDEWEB)

Ito, Atsuo [National Institute of Advanced Industrial Science and Technology (AIST), Institute for Human Science and Biomedical Engineering, Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566 (Japan); Sogo, Yu [National Institute of Advanced Industrial Science and Technology (AIST), Institute for Human Science and Biomedical Engineering, Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566 (Japan); Ebihara, Yuko [School of Science and Technology, Waseda University, 3-4-1 Okubo, Sinjuku-ku, Tokyo 169-8050 (Japan); Onoguchi, Masahiro [School of Science and Technology, Waseda University, 3-4-1 Okubo, Sinjuku-ku, Tokyo 169-8050 (Japan); Oyane, Ayako [National Institute of Advanced Industrial Science and Technology (AIST), Nanotechnology Research Institute, Central 4, Higashi 1-1-1, Tsukuba, Ibaraki 305-8562 (Japan); Ichinose, Noboru [School of Science and Technology, Waseda University, 3-4-1 Okubo, Sinjuku-ku, Tokyo 169-8050 (Japan)

2007-09-15

An ascorbate-apatite composite layer was successfully formed on NaOH- and heat-treated titanium by coprecipitating L-ascorbic acid phosphate and low-crystalline apatite in a supersaturated calcium phosphate solution at 37 {sup 0}C for 48 h. The supersaturated calcium phosphate solutions used have chemical compositions attainable by mixing infusion fluids officially approved for clinical use. The amount of immobilized L-ascorbic acid phosphate ranged from 1.0 to 2.3 {mu}g mm{sup -2}, which is most likely to be sufficient for the in vitro osteogenic differentiation of mesenchymal stem cells on titanium. Since ascorbate is important for the collagen synthesis and subsequent osteogenesis of mesenchymal stem cells, titanium coated with the ascorbate-apatite composite layer would be useful as a scaffold in bone tissue engineering and as a bone substitute.

Formation of an ascorbate-apatite composite layer on titanium

International Nuclear Information System (INIS)

Ito, Atsuo; Sogo, Yu; Ebihara, Yuko; Onoguchi, Masahiro; Oyane, Ayako; Ichinose, Noboru

2007-01-01

An ascorbate-apatite composite layer was successfully formed on NaOH- and heat-treated titanium by coprecipitating L-ascorbic acid phosphate and low-crystalline apatite in a supersaturated calcium phosphate solution at 37 0 C for 48 h. The supersaturated calcium phosphate solutions used have chemical compositions attainable by mixing infusion fluids officially approved for clinical use. The amount of immobilized L-ascorbic acid phosphate ranged from 1.0 to 2.3 μg mm -2 , which is most likely to be sufficient for the in vitro osteogenic differentiation of mesenchymal stem cells on titanium. Since ascorbate is important for the collagen synthesis and subsequent osteogenesis of mesenchymal stem cells, titanium coated with the ascorbate-apatite composite layer would be useful as a scaffold in bone tissue engineering and as a bone substitute

Effect of small glass composition changes on flue gas emissions of glass furnaces

NARCIS (Netherlands)

Limpt, J.A.C. van; Beerkens, R.G.C.; Kersbergen, M.J. van

2008-01-01

Relatively small changes in glass composition might have drastic consequences on the evaporation rates of volatile glass components in glass melting furnaces. Transpiration evaporation tests have been applied to measure the impact of minor glass composition changes on the evaporation rates of

Solid Particle Erosion Behaviors of Carbon-Fiber Epoxy Composite and Pure Titanium

Science.gov (United States)

Cai, Feng; Gao, Feng; Pant, Shashank; Huang, Xiao; Yang, Qi

2016-01-01

Rotor blades of Bell CH-146 Griffon helicopter experience excessive solid particle erosion at low altitudes in desert environment. The rotor blade is made of an advanced light-weight composite which, however, has a low resistance to solid particle erosion. Coatings have been developed and applied to protect the composite blade. However, due to the influence of coating process on composite material, the compatibility between coating and composite base, and the challenges of repairing damaged coatings as well as the inconsistency between the old and new coatings, replaceable thin metal shielding is an alternative approach; and titanium, due to its high-specific strength and better formability, is an ideal candidate. This work investigates solid particle erosion behaviors of carbon-fiber epoxy composite and titanium in order to assess the feasibility of titanium as a viable candidate for erosion shielding. Experiment results showed that carbon-fiber epoxy composite showed a brittle erosion behavior, whereas titanium showed a ductile erosion mode. The erosion rate on composite was 1.5 times of that on titanium at impingement angle 15° and increased to 5 times at impact angle 90°.

X-ray absorption study of Ti-bearing silicate glasses

OpenAIRE

Dingwell, Donald B.; Paris, Eleonora; Seifert, Friedrich; Mottana, Annibale; Romano, Claudia

1994-01-01

Ti K-edge XANES spectra have been collected on a series of Ti-bearing silicate glasses with metasilicate and tetrasilicate compositions. The intensity of the preedge feature in these spectra has been found to change with glass composition and varies from 29 to 58% (normalized intensity) suggesting a variation in structural environent around the absorbing atom. The pre-edge peak intensity increases for the alkali titanium tetrasilicate glasses from 35% to 58% in the order Li < Na < K < Rb, Cs ...

One-step synthesis of continuous free-standing Carbon Nanotubes-Titanium oxide composite films as anodes for lithium-ion batteries

International Nuclear Information System (INIS)

Gao, Hongxu; Hou, Feng; Wan, Zhipeng; Zhao, Sha; Yang, Deming; Liu, Jiachen; Guo, Anran; Gong, Yuxuan

2015-01-01

Highlights: • CNTs/TiO 2 compoiste films synthesized are continuous and free-standing. • The film can be directly used as flexible, binder-free Lithium-Ion Battery electrode. • The CNTs/TiO 2 electrodes exhibit excellent rate capacity and cyclic stability. • Our strategy is readily applicable to fabricate other CNTs-based composite films. - Abstract: Continuous free-standing Carbon Nanotubes (CNTs)/Titanium oxide (TiO 2 ) composite films were fabricated in a vertical CVD gas flow reactor with water sealing by the One-Step Chemical Vapor Deposition (CVD) approach. The composite films consist of multiple layers of conductive carbon nanotube networks with titanium oxide nanoparticles decorating on carbon nanotube surface. The as-synthesized flexible and transferrable composite films show excellent electrochemical properties, when the content of tetrabutyl titanate is 19.0 wt.%, which can be promising as binder-free anodes for Lithium-Ion Battery (LIB) applications. It demonstrates remarkably high rate capacity of 150 mAh g −1 , as well as excellent high rate cyclic stability over 500 cycles (current density of 3000 mA g −1 ). Such observations can be attributed to the relatively larger surface area and pore volume comparing with pristine CNT films. Great potentials of CNTs/TiO 2 composite films for large-scale production and application in energy devices were shown

Modified titanium surface with gelatin nano gold composite increases osteoblast cell biocompatibility

International Nuclear Information System (INIS)

Lee, Young-Hee; Bhattarai, Govinda; Aryal, Santosh; Lee, Nan-Hee; Lee, Min-Ho; Kim, Tae-Gun; Jhee, Eun-Chung; Kim, Hak-Yong; Yi, Ho-Keun

2010-01-01

This study examined the gelatin nano gold (GnG) composite for surface modification of titanium in addition to insure biocompatibility on dental implants or biomaterials. The GnG composite was constructed by gelatin and hydrogen tetrachloroaurate in presence of reducing agent, sodium borohydrate (NabH 4 ). The GnG composite was confirmed by UV-VIS spectroscopy and transmission electron microscopy (TEM). A dipping method was used to modify the titanium surface by GnG composite. Surface was characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The MC-3T3 E1 cell viability was assessed by trypan blue and the expression of proteins to biocompatibility were analyzed by Western blotting. The GnG composite showed well dispersed character, the strong absorption at 530 nm, roughness, regular crystal and clear C, Na, Cl, P, and Au signals onto titanium. Further, this composite allowed MC-3T3 E1 growth and viability compared to gelatin and pure titanium. It induced ERK activation and the expression of cell adherent molecules, FAK and SPARC, and growth factor, VEGF. However, GnG decreased the level of SAPK/JNK. This shows that GnG composite coated titanium surfaces have a good biocompatibility for osteoblast growth and attachment than in intact by simple and versatile dipping method. Furthermore, it offers good communication between cell and implant surfaces by regulating cell signaling and adherent molecules, which are useful to enhance the biocompatibility of titanium surfaces.

Ceramic composite resistors of B4C modified by TIO2 and glass phase

International Nuclear Information System (INIS)

Klimiec, E.; Zaraska, W.; Stobiecki, T.

1998-01-01

Technical progress in the manufacturing technology of composite materials resulted in arising of new generation of bulk resistors, resistant to high levels of overloads and high temperature. These resistors can be applied in extremely heavy working conditions, for instance in cooperation with ignition circuits. The resistors investigated in our research were performed on the basis of ceramic composite consisted of semiconductor boron carbide B 4 C as conductive phase, aluminium oxide Al 2 O 3 and non-alkali glass as insulators and titanium dioxide TiO 2 . The technological procedure of the fabrication of resistors and the results of the tests, such as temperature dependence of the electrical resistance exploitation trials, are presented. (author)

Spectroscopic and dielectric properties of titanium doped MgO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3} glass system

Energy Technology Data Exchange (ETDEWEB)

Raju, G Naga; Ramesh, N Ch; Naresh, P; Krishna, T L; Srinivasulu, K; Sudhkar, K S V; Rao, P Venkateswara, E-mail: gnag_9@rediffmail.com [Department of Physics, Acharya Nagarjuna University-Nuzvid Campus, Nuzvid - 521 201 (India)

2009-07-15

In this paper we have reported the influence of titanium ions on different spectroscopic and dielectric properties of MgO-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3} glasses. The analysis of result of all these studies has indicated that as the concentration of TiO{sub 2} increased in the glass matrix, there is a gradual transformation of titanium ions from octahedral position to tetrahedral positions and cause to increase the rigidity of glass network.

Predicting the glass transition temperature of bioactive glasses from their molecular chemical composition.

Science.gov (United States)

Hill, Robert G; Brauer, Delia S

2011-10-01

A recently published paper (M.D. O'Donnell, Acta Biomaterialia 7 (2011) 2264-2269) suggests that it is possible to correlate the glass transition temperature (T(g)) of bioactive glasses with their molar composition, based on iterative least-squares fitting of published T(g) data. However, we show that the glass structure is an important parameter in determining T(g). Phase separation, local structural effects and components (intermediate oxides) which can switch their structural role in the glass network need to be taken into consideration, as they are likely to influence the glass transition temperature of bioactive glasses. Although the model suggested by O'Donnell works reasonably well for glasses within the composition range presented, it is oversimplified and fails for glasses outside certain compositional boundaries. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Planar ultra thin glass seals with optical fiber interface for monitoring tamper attacks on security eminent components

Science.gov (United States)

Thiel, M.; Flachenecker, G.; Schade, W.; Gorecki, C.; Thoma, A.; Rathje, R.

2017-11-01

Optical seals consisting of waveguide Bragg grating sensor structures in ultra thin glass transparencies have been developed to cover security relevant objects for detection of unauthorized access. For generation of optical signature in the seals, femtosecond laser pulses were used. The optical seals were connected with an optical fiber to enable external read out of the seal. Different attack scenarios for getting undetected access to the object, covered by the seal, were proven and evaluated. The results presented here, verify a very high level of security. An unauthorized detaching and subsequent replacement by original or copy of the seals for tampering would be accompanied with a very high technological effort, posing a substantial barrier towards an attacker. Additionally, environmental influences like temperature effects have a strong but reproducible influence on signature, which in context of a temperature reference database increases the level of security significantly.

Manufacturing techniques for titanium aluminide based alloys and metal matrix composites

Science.gov (United States)

Kothari, Kunal B.

-sized titanium aluminide powders were rapidly consolidated to form near-net shape titanium aluminide parts in form of small discs and tiles. The rapidly consolidated titanium aluminide parts were found to be fully dense. The microstructure morphology was found to vary with consolidation conditions. The mechanical properties were found to be significantly dependent on microstructure morphology and grain size. Due to rapid consolidation, grain growth during consolidation was limited, which in turn led to enhanced mechanical properties. The high temperature mechanical properties for the consolidated titanium aluminide samples were characterized and were found to retain good mechanical performance up to 700°C. Micron-sized titanium aluminide powders with slightly less Aluminum and small Nb, and Cr additions were rapidly consolidated into near-net shape parts. The consolidated parts were found to exhibit enhanced mechanical performance in terms of ductility and yield strength. The negative effect of Oxygen on the flexural strength at high temperatures was found to be reduced with the addition of Nb. In an effort to further reduce the grain size of the consolidated titanium aluminide samples, the as-received titanium aluminide powders were milled in an attrition mill. The average powder particle size of the powders was reduced by 60% after milling. The milled powders were then rapidly consolidated. The grain size of the consolidated parts was found to be in the sub-micrometer range. The mechanical properties were found to be significantly enhanced due to reduction of grain size in the sub-micrometer range. In order to develop a metal matrix composite based on titanium aluminide matrix reinforced with titanium boride, an experiment to study the effect of rapid consolidation on titanium diboride powders was conducted. Micron-sized titanium diboride powders were consolidated and were found to be 93% dense and exhibited minimal grain growth. The low density of the consolidated part was

Biomimetically-mineralized composite coatings on titanium functionalized with gelatin methacrylate hydrogels

Energy Technology Data Exchange (ETDEWEB)

Tan, Guoxin, E-mail: tanguoxin@126.com [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Zhou, Lei [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Ning, Chengyun, E-mail: imcyning@scut.edu.cn [College of Materials Science and Technology, South China University of Technology, Guangzhou, 510641 (China); Tan, Ying [School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006 (China); Ni, Guoxin [Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515 (China); Liao, Jingwen; Yu, Peng; Chen, Xiaofeng [College of Materials Science and Technology, South China University of Technology, Guangzhou, 510641 (China)

2013-08-15

Immobilizing organic–inorganic hybrid composites onto the implant surface is a promising strategy to improve host acceptance of the implant. The objective of this present study was to obtain a unique macroporous titanium-surface with the organic–mineral composite coatings consisting of gelatin methacrylate hydrogel (GelMA) and hydroxyapatite (HA). A 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) layer was first coated onto the titanium surface, and surface was then covalently functionalized with GelMA using a photochemical method. Mineralization of the GelMA coating on the titanium surface was subsequently carried out by a biomimetic method. After 3-day mineralization, a large number of mineral phases comprising spherical amorphous nanoparticles were found randomly deposited inside GelMA matrix. The resulting mineralized hydrogel composites exhibited a unique rough surface of macroporous structure. The structure of the prepared GelMA/HA composite coating was studied by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectra (EDS), attenuated total refraction Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Water contact angle measurement revealed the hydrophilicity properties of composite coatings. GelMA/HA on titanium after the TMSPMA treatment is very stable when tested in vitro with a PBS solution at 37 °C, due to the role of TMSPMA as a molecular bridge. It was expected that the macroporous GelMA/HA composite coatings might potentially promote and accelerate titanium (Ti)-based implants osseointegration for bone repair and regeneration.

Matrix-reinforcement reactivity in P/M titanium matrix composites

International Nuclear Information System (INIS)

Amigo, V.; Romero, F.; Salvador, M. D.; Busquets, D.

2007-01-01

The high reactivity of titanium and the facility of the same one to form intermetallics makes difficult obtaining composites with this material and brings the need in any case of covering the principal fibres used as reinforcement. To obtain composites of titanium reinforced with ceramic particles ins proposed in this paper, for this reason it turns out to be fundamental to evaluate the reactivity between the matrix and reinforcement. Both titanium nitride and carbide (TiN and TiC) are investigated as materials of low reactivity whereas titanium silicide (TiSi 2 ) is also studied as materials of major reactivity, already stated by the scientific community. This reactivity will be analysed by means of scanning electron microscopy (SEM) there being obtained distribution maps of the elements that allow to establish the possible influence of the sintering temperature and time. Hereby the matrix-reinforcement interactions are optimized to obtain suitable mechanical properties. (Author) 39 refs

Titanium dioxide, single-walled carbon nanotube composites

Science.gov (United States)

Yao, Yuan; Li, Gonghu; Gray, Kimberly; Lueptow, Richard M.

2015-07-14

The present invention provides titanium dioxide/single-walled carbon nanotube composites (TiO.sub.2/SWCNTs), articles of manufacture, and methods of making and using such composites. In certain embodiments, the present invention provides membrane filters and ceramic articles that are coated with TiO.sub.2/SWCNT composite material. In other embodiments, the present invention provides methods of using TiO.sub.2/SWCNT composite material to purify a sample, such as a water or air sample.

Preparation of fullerene/glass composites

Science.gov (United States)

Mattes, Benjamin R.; McBranch, Duncan W.; Robinson, Jeanne M.; Koskelo, Aaron C.; Love, Steven P.

1995-01-01

Synthesis of fullerene/glass composites. A direct method for preparing solid solutions of C.sub.60 in silicon dioxide (SiO.sub.2) glass matrices by means of sol-gel chemistry is described. In order to produce highly concentrated fullerene-sol-gel-composites it is necessary to increase the solubility of these "guests" in a delivery solvent which is compatible with the starter sol (receiving solvent). Sonication results in aggregate disruption by treatment with high frequency sound waves, thereby accelerating the rate of hydrolysis of the alkoxide precursor, and the solution process for the C.sub.60. Depending upon the preparative procedure, C.sub.60 dispersed within the glass matrix as microcrystalline domains, or dispersed as true molecular solutions of C.sub.60 in a solid glass matrix, is generated by the present method.

Glass Composition for the use as a Sealant

DEFF Research Database (Denmark)

2014-01-01

The invention concerns a glass composition for the use as a sealant, particularly in a solid oxide fuel cell (SOFC) or in a solid oxide electrolyser cell (SOEC). The glass composition comprises 35-70 mol% CaO, 5-45 mol% ZnO, 5-50 mol% B2O3, 1-45 mol% SiO2, and 1 mol% or less of each element...... of the group, comprising Ba, Na and Sr, based on the total glass composition. Furthermore, the invention relates to an SOFC and an SOEC employing a sealant of said glass composition....

Composition and property measurements for PHA Phase 4 glasses

International Nuclear Information System (INIS)

Edwards, T.B.

2000-01-01

The results presented in this report are for nine Precipitate Hydrolysis Aqueous (PHA) Phase 4 glasses. Three of the glasses contained HM sludge at 22, 26, and 30 wt% respectively, 10 wt% PHA and 1.25 wt% monosodium titanate (MST), all on an oxide basis. The remaining six glasses were selected from the Phase 1 and Phase 2 studies (Purex sludge) but with an increased amount of MST. The high-end target for MST of 2.5 wt% oxide was missed in Phases 1 and 2 due to ∼30 wt% water content of the MST. A goal of this Phase 4 study was to determine whether this increase in titanium concentration from the MST had any impact on glass quality or processibility. Two of the glasses, pha14c and pha15c, were rebatched and melted due to apparent batching errors with pha14 and pha15. The models currently in the Defense Waste Processing Facility's (DWPF) Product Composition Control System (PCCS) were used to predict durability, homogeneity, liquidus, and viscosity for these nine glasses. All of the HM glasses and half of the Purex glasses were predicted to be phase separated, and consequently prediction of glass durability is precluded with the cument models for those glasses that failed the homogeneity constraint. If one may ignore the homogeneity constraint, the measured durabilities were within the 95% prediction limits of the model. Further efforts will be required to resolve this issue on phase separation (inhomogeneity). The liquidus model predicted unacceptable liquidus temperatures for four of the nine glasses. The approximate, bounding liquidus temperatures measured for all had upper limits of 1,000 C or less. Given the fact that liquidus temperatures were only approximated, the 30 wt% loading of Purex may be near or at the edge of acceptability for liquidus. The measured viscosities were close to the predictions of the model. For the Purex glasses, pha12c and pha15c, the measured viscosities of 28 and 23 poise, respectively, indicate that DWPF processing may be compromised

Calcium titanium silicate based glass-ceramic for nuclear waste immobilisation

Science.gov (United States)

Sharma, K.; Srivastav, A. P.; Goswami, M.; Krishnan, Madangopal

2018-04-01

Titanate based ceramics (synroc) have been studied for immobilisation of nuclear wastes due to their high radiation and thermal stability. The aim of this study is to synthesis glass-ceramic with stable phases from alumino silicate glass composition and study the loading behavior of actinides in glass-ceramics. The effects of CaO and TiO2 addition on phase evolution and structural properties of alumino silicate based glasses with nominal composition x(10CaO-9TiO2)-y(10Na2O-5 Al2O3-56SiO2-10B2O3); where z = x/y = 1.4-1.8 are reported. The glasses are prepared by melt-quench technique and characterized for thermal and structural properties using DTA and Raman Spectroscopy. Glass transition and peak crystallization temperatures decrease with increase of CaO and TiO2 content, which implies the weakening of glass network and increased tendency of glasses towards crystallization. Sphene (CaTiSiO5) and perovskite (CaTiO3) crystalline phases are confirmed from XRD which are well known stable phase for conditioning of actinides. The microsturcture and elemental analysis indicate the presence of actinide in stable crystalline phases.

Fiber glass-bioactive glass composite for bone replacing and bone anchoring implants.

Science.gov (United States)

Vallittu, Pekka K; Närhi, Timo O; Hupa, Leena

2015-04-01

Although metal implants have successfully been used for decades, devices made out of metals do not meet all clinical requirements, for example, metal objects may interfere with some new medical imaging systems, while their stiffness also differs from natural bone and may cause stress-shielding and over-loading of bone. Peer-review articles and other scientific literature were reviewed for providing up-dated information how fiber-reinforced composites and bioactive glass can be utilized in implantology. There has been a lot of development in the field of composite material research, which has focused to a large extent on biodegradable composites. However, it has become evident that biostable composites may also have several clinical benefits. Fiber reinforced composites containing bioactive glasses are relatively new types of biomaterials in the field of implantology. Biostable glass fibers are responsible for the load-bearing capacity of the implant, while the dissolution of the bioactive glass particles supports bone bonding and provides antimicrobial properties for the implant. These kinds of combination materials have been used clinically in cranioplasty implants and they have been investigated also as oral and orthopedic implants. The present knowledge suggests that by combining glass fiber-reinforced composite with particles of bioactive glass can be used in cranial implants and that the combination of materials may have potential use also as other types of bone replacing and repairing implants. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Glass Ceramics Composites Fabricated from Coal Fly Ash and Waste Glass

International Nuclear Information System (INIS)

Angjusheva, B.; Jovanov, V.; Srebrenkoska, V.; Fidancevska, E.

2014-01-01

Great quantities of coal ash are produced in thermal power plants which present a double problem to the society: economical and environmental. This waste is a result of burning of coal at temperatures between 1100-14500C. Fly ash available as fine powder presents a source of important oxides SiO2, Al2O3, Fe2O3, MgO, Na2O, but also consist of small amount of ecologically hazardous oxides such as Cr2O3, NiO, MnO. The combination of the fly ash with waste glass under controlled sintering procedure gave bulk glass-ceramics composite material. The principle of this procedure is presented as a multi barrier concept. Many researches have been conducted the investigations for utilization of fly ash as starting material for various glass–ceramics production. Using waste glass ecologically hazardous components are fixed at the molecular level in the silicate phase and the fabricated new glass-ceramic composites possess significantly higher mechanical properties. The aim of this investigation was to fabricate dense glass ceramic composites using fly ash and waste glass with the potential for its utilization as building material

A new method locating good glass-forming compositions

Energy Technology Data Exchange (ETDEWEB)

Yu, Dechuan [Department of Materials Physics and Chemistry, Northeastern University, No.3-11, Wenhua Road, Shenyang, 110819 (China); Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China); Geng, Yan [Department of Materials Physics and Chemistry, Northeastern University, No.3-11, Wenhua Road, Shenyang, 110819 (China); Li, Zhengkun [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China); Liu, Dingming [Department of Materials Physics and Chemistry, Northeastern University, No.3-11, Wenhua Road, Shenyang, 110819 (China); Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China); Fu, Huameng; Zhu, Zhengwang [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China); Qi, Yang, E-mail: qiyang@imp.neu.edu.cn [Department of Materials Physics and Chemistry, Northeastern University, No.3-11, Wenhua Road, Shenyang, 110819 (China); Zhang, Haifeng, E-mail: hfzhang@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China)

2015-10-15

A new method was proposed to pinpoint the compositions with good glass forming ability (GFA) by combining atomic clusters and mixing entropy. The clusters were confirmed by analyzing competing crystalline phases. The method was applied to the Zr–Al–Ni–Cu–Ag alloy system. A series of glass formers with diameter up to 20 mm were quickly detected in this system. The good glass formers were located only after trying 5 compositions around the calculated composition. The method was also effective in other multi-component systems. This method might provide a new way to understand glass formation and to quickly pinpoint compositions with high GFA. - Highlights: • A new method was proposed to quickly design glass formers with high glass forming ability. • The method of designing pentabasic Zr–Al–Ni–Cu–Ag alloys was applied. • A series of new Zr-based bulk metallic glasses with critical diameter of 20 mm were discovered.

A new method locating good glass-forming compositions

International Nuclear Information System (INIS)

Yu, Dechuan; Geng, Yan; Li, Zhengkun; Liu, Dingming; Fu, Huameng; Zhu, Zhengwang; Qi, Yang; Zhang, Haifeng

2015-01-01

A new method was proposed to pinpoint the compositions with good glass forming ability (GFA) by combining atomic clusters and mixing entropy. The clusters were confirmed by analyzing competing crystalline phases. The method was applied to the Zr–Al–Ni–Cu–Ag alloy system. A series of glass formers with diameter up to 20 mm were quickly detected in this system. The good glass formers were located only after trying 5 compositions around the calculated composition. The method was also effective in other multi-component systems. This method might provide a new way to understand glass formation and to quickly pinpoint compositions with high GFA. - Highlights: • A new method was proposed to quickly design glass formers with high glass forming ability. • The method of designing pentabasic Zr–Al–Ni–Cu–Ag alloys was applied. • A series of new Zr-based bulk metallic glasses with critical diameter of 20 mm were discovered

Innovative Seals for Solid Oxide Fuel Cells (SOFC)

Energy Technology Data Exchange (ETDEWEB)

Singh, Raj

2008-06-30

A functioning SOFC requires different type of seals such as metal-metal, metal-ceramic, and ceramic-ceramic. These seals must function at high temperatures between 600--900{sup o}C and in oxidizing and reducing environments of the fuels and air. Among the different type of seals, the metal-metal seals can be readily fabricated using metal joining, soldering, and brazing techniques. However, the metal-ceramic and ceramic-ceramic seals require significant research and development because the brittle nature of ceramics/glasses can lead to fracture and loss of seal integrity and functionality. Consequently, any seals involving ceramics/glasses require a significant attention and technology development for reliable SOFC operation. This final report is prepared to describe the progress made in the program on the needs, approaches, and performance of high temperature seals for SOFC. In particular, a new concept of self-healing glass seals is pursued for making seals between metal-ceramic material combinations, including some with a significant expansion mismatch.

Glasses, ceramics, and composites from lunar materials

Science.gov (United States)

Beall, George H.

1992-01-01

A variety of useful silicate materials can be synthesized from lunar rocks and soils. The simplest to manufacture are glasses and glass-ceramics. Glass fibers can be drawn from a variety of basaltic glasses. Glass articles formed from titania-rich basalts are capable of fine-grained internal crystallization, with resulting strength and abrasion resistance allowing their wide application in construction. Specialty glass-ceramics and fiber-reinforced composites would rely on chemical separation of magnesium silicates and aluminosilicates as well as oxides titania and alumina. Polycrystalline enstatite with induced lamellar twinning has high fracture toughness, while cordierite glass-ceramics combine excellent thermal shock resistance with high flexural strengths. If sapphire or rutile whiskers can be made, composites of even better mechanical properties are envisioned.

Flexible edge seal for vacuum insulating glazing units

Science.gov (United States)

Bettger, Kenneth J.; Stark, David H.

2012-12-11

A flexible edge seal is provided for a vacuum insulating glazing unit having a first glass pane and a second glass pane spaced-apart from the first. The edge seal comprises a seal member formed of a hermetically bondable material and having a first end, a second end and a center section disposed therebetween. The first end is hermetically bondable to a first glass pane. The second end is hermetically bondable to a second glass pane. The center section comprises a plurality of convolutes.

Influence of titanium volume fraction on the mechanical properties of Mg-Ti composites

Energy Technology Data Exchange (ETDEWEB)

Perez, Pablo; Garces, Gerardo; Adeva, Paloma [Centro Nacional de Investigaciones Metalurgicas (CENIM, CSIC), Madrid (Spain). Dept. de Metalurgia Fisica

2009-03-15

The influence of titanium volume fraction on the mechanical properties of Mg-Ti composites prepared through a powder metallurgy route has been evaluated. Titanium was added as particles smaller than 25 {mu}m and volume fractions ranging from 5 to 15%. The increase in the volume fraction of titanium particles results in a slight decrease in the maximum strength. In contrast to this, the ductility of all composites was significantly enhanced by titanium additions. The mechanical properties can be explained on the basis of texture changes induced by the presence of titanium particles. The decrease in the basal texture along the extrusion direction as the amount of titanium is progressively increased accounts for the decrease in the maximum strength. (orig.)

Titanium-hydroxyapatite composites sintered at low temperature for tissue engineering: in vitro cell support and biocompatibility.

Science.gov (United States)

Comín, Romina; Cid, Mariana P; Grinschpun, Luciano; Oldani, Carlos; Salvatierra, Nancy A

2017-04-26

In clinical orthopedics, a critical problem is the bone tissue loss produced by a disease or injury. The use of composites from titanium and hydroxyapatite for biomedical applications has increased due to the resulting advantageous combination of hydroxyapatite bioactivity and favorable mechanical properties of titanium. Powder metallurgy is a simple and lower-cost method that uses powder from titanium and hydroxyapatite to obtain composites having hydroxyapatite phases in a metallic matrix. However, this method has certain limitations arising from thermal decomposition of hydroxyapatite in the titanium-hydroxyapatite system above 800°C. We obtained a composite from titanium and bovine hydroxyapatite powders sintered at 800°C and evaluated its bioactivity and cytocompatibility according to the ISO 10993 standard. Surface analysis and bioactivity of the composite was evaluated by X-ray diffraction and SEM. MTT assay was carried out to assess cytotoxicity on Vero and NIH3T3 cells. Cell morphology and cell adhesion on the composite surface were analyzed using fluorescence and SEM. We obtained a porous composite with hydroxyapatite particles well integrated in titanium matrix which presented excellent bioactivity. Our data did not reveal any toxicity of titanium-hydroxyapatite composite on Vero or NIH3T3 cells. Moreover, extracts from composite did not affect cell morphology or density. Finally, NIH3T3 cells were capable of adhering to and proliferating on the composite surface. The composite obtained displayed promising biomedical applications through the simple method of powder metallurgy. Additionally, these findings provide an in vitro proof for adequate biocompatibility of titanium-hydroxyapatite composite sintered at 800°C.

GLASS COMPOSITION-TCLP RESPONSE MODEL FOR WASTE GLASSES

International Nuclear Information System (INIS)

Kim, Dong-Sang; Vienna, John D.

2004-01-01

A first-order property model for normalized Toxicity Characteristic Leaching Procedure (TCLP) release as a function of glass composition was developed using data collected from various studies. The normalized boron release is used to estimate the release of toxic elements based on the observation that the boron release represents the conservative release for those constituents of interest. The current TCLP model has two targeted application areas: (1) delisting of waste-glass product as radioactive (not mixed) waste and (2) designating the glass wastes generated from waste-glass research activities as hazardous or non-hazardous. This paper describes the data collection and model development for TCLP releases and discusses the issues related to the application of the model

The manufacture and properties of a glass fabric/epoxy composite bellows

International Nuclear Information System (INIS)

Evans, D.; Langridge, J.U.D.; Morgan, J.T.

1978-01-01

This bellows is a small but critical part of a large bubble chamber at present being constructed. It forms a gas tight seal between the reciprocating piston and the stationary chamber walls separating the chamber liquid from the piston backing gas. It is tubular (800 mm diameter) containing only one convolution and operates at a temperature of 26K in a 3 tesla magnetic field. For this latter reason, a polymeric material is preferred since this avoids eddy current heating effects. During normal operation of the bubble chamber the bellows is required to accommodate the total stroke of the piston (+-3.5 mm) and to withstand a pressure swing of +-3 bar at a frequency of 30 Hz. Detailed consideration of these operating parameters confirms the need for high quality glass reinforced plastics material. This paper describes the moulding technique, first developed for a 300 mm diameter bellows successfully used in a similar application. It produces a composite of the complex shape required, to close dimensional tolerances and with a glass fabric content in excess of 60% by weight. (author)

Controlling the length scale and distribution of the ductile phase in metallic glass composites through friction stir processing.

Science.gov (United States)

Arora, Harpreet Singh; Mridha, Sanghita; Grewal, Harpreet Singh; Singh, Harpreet; Hofmann, Douglas C; Mukherjee, Sundeep

2014-06-01

We demonstrate the refinement and uniform distribution of the crystalline dendritic phase by friction stir processing (FSP) of titanium based in situ ductile-phase reinforced metallic glass composite. The average size of the dendrites was reduced by almost a factor of five (from 24 μ m to 5 μ m) for the highest tool rotational speed of 900 rpm. The large inter-connected dendrites become more fragmented with increased circularity after processing. The changes in thermal characteristics were measured by differential scanning calorimetry. The reduction in crystallization enthalpy after processing suggests partial devitrification due to the high strain plastic deformation. FSP resulted in increased hardness and modulus for both the amorphous matrix and the crystalline phase. This is explained by interaction of shear bands in amorphous matrix with the strain-hardened dendritic phase. Our approach offers a new strategy for microstructural design in metallic glass composites.

PIXE characterization of tissues surrounding metallic prostheses coated with biological glasses

International Nuclear Information System (INIS)

Barbotteau, Y.; Irigaray, J.L.; Moretto, Ph.

2004-01-01

Biological glasses can be used as coatings for metallic prostheses in order to prevent corrosion. According to their composition, these glasses have different properties. We studied, in vivo, two glasses referred to as BVA and BVH. They are used as coatings of Ti6Al4V metallic implant. BVA glass disappears after 3 months of implantation and is replaced by bone. Prostheses initially coated by this glass have a larger osseous contact perimeter compared to the uncoated prostheses. This ensures a better anchoring of the implant and limits the micro-motions which cause wear debris. BVH glass keeps a constant composition during implantation and it is used like a layer which isolates metal implant from biological environment. In order to characterize the bony environment surrounding implants, we have used PIXE and RBS methods. This paper shows results of the behavior of bony tissue under micro-beam, the quality tests of new bone which replaces the BVA glass coating and the evaluation of corrosion effects. Titanium release in bony tissues begins when the metal surface of the prosthesis is exposed to biological fluids. After a few months of implantation, the titanium contamination is stabilized and remains localized within the first tens of micrometers of surrounding bone

Development and application of new composite grouting material for sealing groundwater inflow and reinforcing wall rock in deep mine.

Science.gov (United States)

Jinpeng, Zhang; Limin, Liu; Futao, Zhang; Junzhi, Cao

2018-04-04

With cement, bentonite, water glass, J85 accelerator, retarder and water as raw materials, a new composite grouting material used to seal groundwater inflow and reinforce wall rock in deep fractured rock mass was developed in this paper. Based on the reaction mechanism of raw material, the pumpable time, stone rate, initial setting time, plastic strength and unconfined compressive strength of multi-group proportion grouts were tested by orthogonal experiment. Then, the optimum proportion of composite grouting material was selected and applied to the grouting engineering for sealing groundwater inflow and reinforcing wall rock in mine shaft lining. The results show the mixing proportion of the maximum pumpable time, maximum stone rate and minimum initial setting time of grout are A K4 B K1 C K4 D K2 , A K3 B K1 C K1 D K4 and A K3 B K3 C K4 D K1 , respectively. The mixing proportion of the maximum plastic strength and unconfined compressive strength of grouts concretion bodies are A K1 B K1 C K1 D K3 and A K1 B K1 C K1 D K1 , respectively. Balanced the above 5 indicators overall and determined the optimum proportion of grouts: bentonite-cement ratio of 1.0, water-solid ratio of 3.5, accelerator content of 2.9% and retarder content of 1.45%. This new composite grouting material had good effect on the grouting engineering for sealing groundwater inflow and reinforcing wall rock in deep fractured rock mass.

The influence of glass composition on crystalline phase stability in glass-ceramic wasteforms

International Nuclear Information System (INIS)

Maddrell, Ewan; Thornber, Stephanie; Hyatt, Neil C.

2015-01-01

Highlights: • Crystalline phase formation shown to depend on glass matrix composition. • Zirconolite forms as the sole crystalline phase only for most aluminous glasses. • Thermodynamics indicate that low silica activity glasses stabilise zirconolite. - Abstract: Zirconolite glass-ceramic wasteforms were prepared using a suite of Na 2 O–Al 2 O 3 –B 2 O 3 –SiO 2 glass matrices with variable Al:B ratios. Zirconolite was the dominant crystalline phase only for the most alumina rich glass compositions. As the Al:B ratio decreased zirconolite was replaced by sphene, zircon and rutile. Thermodynamic data were used to calculate a silica activity in the glass melt below which zirconolite is the favoured crystalline phase. The concept of the crystalline reference state of glass melts is then utilised to provide a physical basis for why silica activity varies with the Al:B ratio

Predicting bioactive glass properties from the molecular chemical composition: glass transition temperature.

Science.gov (United States)

O'Donnell, Matthew D

2011-05-01

The glass transition temperature (T(g)) of inorganic glasses is an important parameter than can be used to correlate with other glass properties, such as dissolution rate, which governs in vitro and in vivo bioactivity. Seven bioactive glass compositional series reported in the literature (77 in total) were analysed here with T(g) values obtained by a number of different methods: differential thermal analysis, differential scanning calorimetry and dilatometry. An iterative least-squares fitting method was used to correlate T(g) from thermal analysis of these compositions with the levels of individual oxide and fluoride components in the glasses. When all seven series were fitted a reasonable correlation was found between calculated and experimental values (R(2)=0.89). When the two compositional series that were designed in weight percentages (the remaining five were designed in molar percentage) were removed from the model an improved fit was achieved (R(2)=0.97). This study shows that T(g) for a wide range in compositions (e.g. SiO(2) content of 37.3-68.4 mol.%) can be predicted to reasonable accuracy enabling processing parameters to be predicted such as annealing, fibre-drawing and sintering temperatures. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Glass Transition Temperature- and Specific Volume- Composition Models for Tellurite Glasses

Energy Technology Data Exchange (ETDEWEB)

Riley, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Vienna, John D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2017-09-01

This report provides models for predicting composition-properties for tellurite glasses, namely specific gravity and glass transition temperature. Included are the partial specific coefficients for each model, the component validity ranges, and model fit parameters.

Mechanical characterization of glass fiber (woven roving/chopped strand mat E-glass fiber) reinforced polyester composites

Science.gov (United States)

Bhaskar, V. Vijaya; Srinivas, Kolla

2017-07-01

Polymer reinforced composites have been replacing most of the engineering material and their applications become more and more day by day. Polymer composites have been analyzing from past thirty five years for their betterment for adapting more applications. This paper aims at the mechanical properties of polyester reinforced with glass fiber composites. The glass fiber is reinforced with polyester in two forms viz Woven Rovings (WRG) and Chopped Strand Mat (CSMG) E-glass fibers. The composites are fabricated by hand lay-up technique and the composites are cut as per ASTM Standard sizes for corresponding tests like flexural, compression and impact tests, so that flexural strength, compression strength, impact strength and inter laminar shear stress(ILSS) of polymer matrix composites are analyzed. From the tests and further calculations, the polyester composites reinforced with Chopped Strand Mat glass fiber have shown better performance against flexural load, compression load and impact load than that of Woven Roving glass fiber.

Chemical Composition Measurements of LAWA44 Glass Samples

Energy Technology Data Exchange (ETDEWEB)

Fox, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Riley, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-11-15

DOE is building the Hanford Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site in Washington to remediate 55 million gallons of radioactive waste that is temporarily stored in 177 underground tanks. Both low-activity and high-level wastes will then be vitrified into borosilicate glass using Joule-heated ceramic melters. Efforts are being made to increase the loading of Hanford tank wastes in the glass. One area of work is enhancing waste glass composition/property models and broadening the compositional regions over which those models are applicable. In this report, the Savannah River National Laboratory provides chemical analysis results for several samples of a simulated low-activity waste glass, LAWA44, provided by the Pacific Northwest National Laboratory as part of an ongoing development task. The measured chemical composition data are reported and compared with the targeted values for each component for each glass. A detailed review showed no indications of errors in the preparation or measurement of the study glasses. All of the measured sums of oxides for the study glasses fell within the interval of 97.9 to 102.6 wt %, indicating acceptable recovery of the glass components. Comparisons of the targeted and measured chemical compositions showed that the measured values for the glasses met the targeted concentrations within 10% for those components present at more than 5 wt %. It was noted that the measured B₂O₃ concentrations are somewhat above the targeted values for the study glasses. No obvious trends were observed with regard to the multiple melting steps used to prepare the study glasses, indicating that any potential effects of volatility were below measurable thresholds.

Dynamic performance of a C/C composite finger seal in a tilting mode

Directory of Open Access Journals (Sweden)

Hailin ZHAO

2017-08-01

Full Text Available The complex operating state of aeroengines has an impact on the performance of finger seals. However, little work has been focused on the issue and the dynamic performance of finger seals is also rarely studied. Therefore, a distributed mass equivalent model considering working conditions is proposed in this paper for solving the existing problems. The effects of the fiber bundle density and the preparation direction of the fiber bundle of a C/C composite on the dynamic performance of a finger seal are investigated in rotor tilt based on the proposed model. The difference between the C/C composite finger seal performances under the rotor precession and nutation tilt cases is also investigated. The results show that the fiber bundle density and the preparation direction of the fiber bundle have an influence on the dynamic performance of the finger seal as rotor tilt is considered, and the dynamic performance of the finger seal is different in the two kinds of tilting modes. In addition, a novel method for design of finger seals is presented based on the contact pressure between finger boots and the rotor. Finger seals with good leakage rates and low wear can be acquired in this method.

Effect of sintering temperature on the microstructure and properties of foamed glass-ceramics prepared from high-titanium blast furnace slag and waste glass

Science.gov (United States)

Chen, Chang-hong; Feng, Ke-qin; Zhou, Yu; Zhou, Hong-ling

2017-08-01

Foamed glass-ceramics were prepared via a single-step sintering method using high-titanium blast furnace slag and waste glass as the main raw materials The influence of sintering temperature (900-1060°C) on the microstructure and properties of foamed glass-ceramics was studied. The results show that the crystal shape changed from grainy to rod-shaped and finally turned to multiple shapes as the sintering temperature was increased from 900 to 1060°C. With increasing sintering temperature, the average pore size of the foamed glass-ceramics increased and subsequently decreased. By contrast, the compressive strength and the bulk density decreased and subsequently increased. An excessively high temperature, however, induced the coalescence of pores and decreased the compressive strength. The optimal properties, including the highest compressive strength (16.64 MPa) among the investigated samples and a relatively low bulk density (0.83 g/cm3), were attained in the case of the foamed glass-ceramics sintered at 1000°C.

In vitro behaviour of three biocompatible glasses in composite implants.

Science.gov (United States)

Varila, Leena; Lehtonen, Timo; Tuominen, Jukka; Hupa, Mikko; Hupa, Leena

2012-10-01

Poly(L,DL-lactide) composites containing filler particles of bioactive glasses 45S5 and S53P4 were compared with a composite containing a slowly dissolving glass S68. The in vitro reactivity of the composites was studied in simulated body fluid, Tris-buffered solution, and phosphate buffered saline. The high processing temperature induced thermal degradation giving cavities in the composites containing 45S5 and S53P4, while good adhesion of S68 to the polymer was observed. The cavities partly affected the in vitro reactivity of the composites. The degradation of the composites containing the bioactive glasses was faster in phosphate buffered saline than in the two other solutions. Hydroxyapatite precipitation suggesting bone tissue bonding capability was observed on these two composites in all three solutions. The slower dissolution of S68 glass particles and the limited hydroxyapatite precipitation suggested that this glass has potential as a reinforcing composition with the capability to guide bone tissue growth in biodegradable polymer composites.

Cesium titanium silicate and method of making

Science.gov (United States)

Balmer, Mari L.

1997-01-01

The invention is the new material, a ternary compound of cesium, silica, and titania, together with a method of making the ternary compound, cesium titanium silicate pollucite. More specifically, the invention is Cs.sub.2 Ti.sub.2 Si.sub.4 O.sub.13 pollucite which is a new crystalline phase representing a novel class of Ti-containing zeolites. Compositions contain relatively high Cs.sub.2 O and TiO.sub.2 loadings and are durable glass and ceramic materials. The amount of TiO.sub.2 and Cs.sub.2 that can be incorporated into these glasses and crystalline ceramics far exceeds the limits set for the borosilicate high level waste glass.

Effect of sintering temperatures on titanium matrix composites reinforced by ceramic particles

Energy Technology Data Exchange (ETDEWEB)

Romero, F.; Amigo, V.; Busquets, D.; Klyatskina, E. [Mechanical and Materials Engineering Department. Polytechnical University of Valencia, Valencia (Spain)

2005-07-01

Titanium and titanium composites have a potential use in aerospace and biotechnology industries, and nowadays in others like sports and fashion ones. In this work composite materials, based on titanium matrix reinforced with ceramic particles, have been developed. PM route is used to obtain compact and sintered samples. TiN and TiAl powders, are milled with Ti powder in different volumetric percentages in a ball mill. These mixtures are pressed in a uniaxial press and sintered in a vacuum furnace at different temperatures between 1180 to 1220 deg. C. Porosity of samples is analysed, before and after the sintering process, by Archimedes technique and by image analysis. Mechanical properties and the reinforcement particles influence in the titanium matrix are studied by flexion test in green and sintered states, and by hardness and microhardness tests. Complimentarily, a microstructural analysis is carried out by optical and electron microscopy, and the reactivity between the reinforce particles and titanium matrix are studied. (authors)

Effect of artificial aging on the roughness and microhardness of sealed composites.

Science.gov (United States)

Catelan, Anderson; Briso, André L F; Sundfeld, Renato H; Dos Santos, Paulo H

2010-10-01

  The application of surface sealant could improve the surface quality and success of composite restorations; however, it is important to assess the behavior of this material when subjected to aging procedures.   To evaluate the effect of artificial aging on the surface roughness and microhardness of sealed microhybrids and nanofilled composites.   One hundred disc-shaped specimens were made for each composite. After 24 hours, all samples were polished and surface sealant was applied to 50 specimens of each composite. Surface roughness (Ra) was determined with a profilometer and Knoop microhardness was assessed with a 50-g load for 15 seconds. Ten specimens of each group were aged during 252 hours in a UV-accelerated aging chamber or immersed for 28 days in cola soft drink, orange juice, red wine staining solutions, or distilled water. Data were analyzed by two-way analysis of variance and Fischer's test (α=0.05).   Artificial aging decreased microhardness values for all materials, with the exceptions of Vit-l-escence (Ultradent Products Inc., South Jordan UT, USA) and Supreme XT (3M ESPE, St. Paul, MN, USA) sealed composites; surface roughness values were not altered. Water storage had less effect on microhardness, compared with the other aging processes. The sealed materials presented lower roughness and microhardness values, when compared with unsealed composites.   Aging methods decreased the microhardness values of a number of composites, with the exception of some sealed composites, but did not alter the surface roughness of the materials. The long-term maintenance of the surface quality of materials is fundamental to improving the longevity of esthetic restorations. In this manner, the use of surface sealants could be an important step in the restorative procedure using resin-based materials. © 2010, COPYRIGHT THE AUTHORS. JOURNAL COMPILATION © 2010, WILEY PERIODICALS, INC.

Effect of Minor Titanium Addition on Copper/Diamond Composites Prepared by Hot Forging

Science.gov (United States)

Yang, Fei; Sun, Wei; Singh, Ajit; Bolzoni, Leandro

2018-03-01

Copper/diamond composites have great potential to lead the next generation of advanced heat sink materials for use in high-power electronic devices and high-density integrated circuits because of their potential excellent properties of high thermal conductivity and close thermal expansion to the chip materials (e.g., Si, InP, GaAs). However, the poor wettability between copper and diamond presents a challenge for synthesizing copper/diamond composites with effective metallurgical bonding and satisfied thermal performance. In this article, copper/diamond composites were successfully prepared by hot forging of elemental copper and artificial diamond powders with small amounts (0 vol.%, 3 vol.% and 5 vol.%) of titanium additives. Microstructure observation and mechanical tests showed that adding minor titanium additions in the copper/diamond composite resulted in fewer cracks in the composites' microstructure and significantly improved the bonding between the copper and diamond. The strongest bonding strength was achieved for the copper/diamond composite with 3 vol.% titanium addition, and the possible reasons were discussed.

Thermal recycling and re-manufacturing of glass fibre thermosetting composites

DEFF Research Database (Denmark)

Fraisse, Anthony; Beauson, Justine; Brøndsted, Povl

2016-01-01

The impact of using thermally recycled glass fibre in re-manufactured composites was investigated. A unidirectional glass fibre thermosetting composite laminate was manufactured. The matrix in one part of the laminate was burnt off to recover the glass fibres. These recycled glass fibres were used...

Engineered high expansion glass-ceramics having near linear thermal strain and methods thereof

Energy Technology Data Exchange (ETDEWEB)

Dai, Steve Xunhu; Rodriguez, Mark A.; Lyon, Nathanael L.

2018-01-30

The present invention relates to glass-ceramic compositions, as well as methods for forming such composition. In particular, the compositions include various polymorphs of silica that provide beneficial thermal expansion characteristics (e.g., a near linear thermal strain). Also described are methods of forming such compositions, as well as connectors including hermetic seals containing such compositions.

Composition-Structure-Property Relationships in Boroaluminosilicate Glasses

DEFF Research Database (Denmark)

Zheng, Qiuju; Potuzak, M.; Mauro, J.C.

2012-01-01

boroaluminosilicate glasses from peralkaline to peraluminous compositions by substituting Al2O3 for SiO2. Our results reveal a pronounced change in all the measured physical properties (density, elastic moduli, hardness, glass transition temperature, and liquid fragility) around [Al2O3]–[Na2O]=0. The structural......The complicated structural speciation in boroaluminosilicate glasses leads to a mixed network former effect yielding nonlinear variation in many macroscopic properties as a function of chemical composition. Here we study the composition–structure–property relationships in a series of sodium...

Low melting high lithia glass compositions and methods

Science.gov (United States)

Jantzen, Carol M.; Pickett, John B.; Cicero-Herman, Connie A.; Marra, James C.

2000-01-01

The invention relates to methods of vitrifying waste and for lowering the melting point of glass forming systems by including lithia formers in the glass forming composition in significant amounts, typically from about 0.16 wt % to about 11 wt %, based on the total glass forming oxides. The lithia is typically included as a replacement for alkali oxide glass formers that would normally be present in a particular glass forming system. Replacement can occur on a mole percent or weight percent basis, and typically results in a composition wherein lithia forms about 10 wt % to about 100 wt % of the alkali oxide glass formers present in the composition. The present invention also relates to the high lithia glass compositions formed by these methods. The invention is useful for stabilization of numerous types of waste materials, including aqueous waste streams, sludge solids, mixtures of aqueous supernate and sludge solids, combinations of spent filter aids from waste water treatment and waste sludges, supernate alone, incinerator ash, incinerator offgas blowdown, or combinations thereof, geological mine tailings and sludges, asbestos, inorganic filter media, cement waste forms in need of remediation, spent or partially spent ion exchange resins or zeolites, contaminated soils, lead paint, etc. The decrease in melting point achieved by the present invention desirably prevents volatilization of hazardous or radioactive species during vitrification.

Effect of the polymeric coating thickness on the photocurrent performance of titanium dioxide nanorod arrays-polyaniline composite-based UV photosensor

Science.gov (United States)

Yusoff, M. M.; Mamat, M. H.; Malek, M. F.; Othman, , N.; Ismail, A. S.; Saidi, S. A.; Mohamed, R.; Suriani, A. B.; Khusaimi, Z.; Rusop, M.

2018-05-01

Titanium dioxide (TiO2) nanorod arrays (TNAs) were synthesized and deposited on fluorine tin oxide (FTO)-coated glass substrate using a one-step immersion method in a glass container. The effect of the polymeric coating thickness of p-type polyaniline (PANI) on the n-type TNAs was investigated in the p-n heterojunction photodiode (PD) for the application of ultraviolet (UV) photosensor. The fabricated photosensor demonstrated an increased photocurrent under UV irradiation in correlation with the thickness layer of PANI. The measured UV response showed the highest photocurrent of 0.014 µA at 1.0 V of reverse bias with low dark current under the UV radiation (365 nm, 750 µW/cm2). The thickness of the PANI film improved the photocurrent of the fabricated TNAs/PANI composite-based UV photosensor.

Composite materials and bodies including silicon carbide and titanium diboride and methods of forming same

Science.gov (United States)

Lillo, Thomas M.; Chu, Henry S.; Harrison, William M.; Bailey, Derek

2013-01-22

Methods of forming composite materials include coating particles of titanium dioxide with a substance including boron (e.g., boron carbide) and a substance including carbon, and reacting the titanium dioxide with the substance including boron and the substance including carbon to form titanium diboride. The methods may be used to form ceramic composite bodies and materials, such as, for example, a ceramic composite body or material including silicon carbide and titanium diboride. Such bodies and materials may be used as armor bodies and armor materials. Such methods may include forming a green body and sintering the green body to a desirable final density. Green bodies formed in accordance with such methods may include particles comprising titanium dioxide and a coating at least partially covering exterior surfaces thereof, the coating comprising a substance including boron (e.g., boron carbide) and a substance including carbon.

Research on the Properties of the Waste Glass Concrete Composite Foundation

Science.gov (United States)

Jia, Shilong; Chen, Kaihui; Chen, Zhongliang

2018-02-01

The composite foundation of glass concrete can not only reuse the large number of waste glass, but also improve the bearing capacity of weak foundation and soil with special properties. In this paper, the engineering properties of glass concrete composite foundation are studied based on the development situation of glass concrete and the technology of composite foundation.

Apparatus for sealing access holes to cavities within the earth with rock glass

International Nuclear Information System (INIS)

Holman, R.R.

1979-01-01

Apparatus is disclosed for establishing a solid, very low permeable rock glass plug to seal access holes through rock to underground storage vaults. The apparatus is designed to supply a filler material having a constituency substantially matching that of the rock formation surrounding the access port to the vault, through a central feeder tube under pressure to the vault. Means are provided for heating the filler material and surrounding rock formation at the point where the filler material exits the feeder tube, to a temperature sufficient to melt both the rock formation and the filler material. The remaining portion of the feeder tube is cooled to preserve the surrounding rock formaion spaced from the feeder orifice. The melt at the extremity of the feeder tube is forced through the orifice to a region below the tool by the force of the pressure feed. As the melt is forced below the tool, the tool is retracted until the access hole is completely sealed. A second embodiment is provided to seal enlarged openings which further includes a cooled core follower that enables the deposit to be fused in layers closing in the circumference of the hole until a final pass fuses the central core

Testing of neutron-irradiated ceramic-to-metal seals

International Nuclear Information System (INIS)

Brown, R.D.; Clinard, F.W. Jr.; Lopez, M.R.; Martinez, H.; Romero, T.J.; Cook, J.H.; Barr, H.N.; Hittman, F.

1990-01-01

This paper reports on ceramic-to-metal seals prepared by sputtering a titanium metallizing layer onto ceramic disks and then brazing to metal tubes. The ceramics used were alumina, MACOR, spinel, AlON, and a mixture of Al 2 O 3 and Si 3 N 4 . Except for the MACOR, which was brazed to a titanium tube, the ceramics were brazed to niobium tubes. The seals were leak tested and then sent to Los Alamos National Laboratory, where they were irradiated using the spallation neutron source at the Los Alamos Meson Physics Facility. Following irradiation for ∼ 90 days to a fluence of 2.8 x 10 23 n/m 2 , the samples were moved to hot cells and again leak tested. Only the MACOR samples showed any measurable leaks. One set of samples was then pressurized to 6.9 MPa (1000 psi) and subsequently leak tested. No leaks were found. Bursting the seals required hydrostatic pressures of at least 34 MPa (5000 psi). The high seal strength and few leaks indicate that ceramic-to-metal seals can resist radiation-induced degradation

Test Method Variability in Slow Crack Growth Properties of Sealing Glasses

Science.gov (United States)

Salem, J. A.; Tandon, R.

2010-01-01

The crack growth properties of several sealing glasses were measured by using constant stress rate testing in 2 and 95 percent RH (relative humidity). Crack growth parameters measured in high humidity are systematically smaller (n and B) than those measured in low humidity, and crack velocities for dry environments are 100x lower than for wet environments. The crack velocity is very sensitive to small changes in RH at low RH. Biaxial and uniaxial stress states produced similar parameters. Confidence intervals on crack growth parameters that were estimated from propagation of errors solutions were comparable to those from Monte Carlo simulation. Use of scratch-like and indentation flaws produced similar crack growth parameters when residual stresses were considered.

Ceramic fiber reinforced glass-ceramic matrix composite

Science.gov (United States)

Bansal, Narottam P. (Inventor)

1993-01-01

A slurry of BSAS glass powders is cast into tapes which are cut to predetermined sizes. Mats of continuous chemical vapor deposition (CVD)-SiC fibers are alternately stacked with these matrix tapes. This tape-mat stack is warm-pressed to produce a 'green' composite which is heated to burn out organic constituents. The remaining interim material is then hot-pressed to form a BSAS glass-ceramic fiber-reinforced composite.

DETERMINATION OF PHASE COMPOSITION OF SEALING COATING BASED ON APC (ALUMINOPHOSPHATE COMPOUNDS

Directory of Open Access Journals (Sweden)

BOLSHAKOV V. I.

2017-02-01

Full Text Available Summary. Goal. To investigate the phase composition of the obtained sealing coatings based on aluminophosphate compound (APC and the impact of temperature rise on it. Methods. Qualitative X-ray phase analysis (XRPA and differential thermal analysis (DTA are used as the methods of research. Roentgenograms for structural analysis were obtained on a DRON-4-07 using filtered copper radiation in the secondary beam. Registration and initial processing of diffraction patterns was performed using the software package PDOS with the output of the diffraction patterns on the screen. Using the "loupe" option allowed to identify weak interference lines, which increased the accuracy of the method of qualitative XRPA. The thermograms for DTA received on the device type Termoskan-2. The results. It is revealed that base of coating is X-ray amorphous phase. There are following crystalline phases: Al, AlPO4, Al (PO3 3, BN found in the coating. It is revealed that annealing doesn’t make a significant influence on the phase composition of the crystalline phases and the coating doesn’t lose properties after annealing during repeated thermal stress. Scientific novelty. The phase composition of the proposed sealing coatings based on APC and produced by plasma spraying, and the effect of annealing on the phase composition of the coating are investigated. The reaction of synthesis of primary material forming on the basis of APC for coating is offered. Practical significance. The results can be used in aviation technology in the development of gas turbine engines (GTE and the design of the compressors. The sealing coating may be used to improve the reliability of the compressor and to increase the efficiency ratio of turbine engine. During the operation the compressor’s blades touch the sealing coating of compressor’s stator and grooves it without causing locking and destruction of the rotor. Therefore, the development of new sealing coating compositions that

Influence of nuclear glasses composition on their liability to deterioration

International Nuclear Information System (INIS)

Tovena, I.

1995-01-01

The aim of this thesis is to contribute to the study of the nuclear glasses composition influence on their liability to deterioration. The methodology of the experimental research used has lead to define between the thirty oxides which form the reference glass light water, six oxides of interest. For each of these oxides, a composition variation area has been defined. A matrix of twenty glass compositions has then been defined. The preparation of materials of these compositions has sometimes lead to materials weakly heterogeneous which have been characterized before deterioration. This study has been completed by those of three glasses in a composition variation area narrower of the light water nuclear glass : the R7T7 and two glasses at limits having respectively an initial dissolution velocity at 100 degrees Celsius theoretically maximum and minimum. Some deterioration parameters in pure water have been experimentally measured on the twenty three glasses : 1) an initial dissolution velocity at 100 degrees (Vo 1 00) Celsius and another one at 90 degrees Celsius (Vo 9 0) 2) a dissolution velocity in conditions near the saturation at 90 degrees Celsius 3) an apparent solubility of glass based on the ortho silicic acid activity 4) the evolution of the dissolution kinetics at 90 degrees Celsius in sub-saturated medium towards saturated medium 5) the alteration films nature developed at the glasses surface during these last alteration tests. Some thermodynamic and structural models have been studied in order to predict Vo 9 0 and Vo 1 00. The dissolution kinetic law developed from reference glass dissolution results has been studied with the calculation code LIXIVER. It has not been able to be used for most of the glasses compositions studied. As a consequence, the glasses dissolution control by a surface reaction which are itself controlled by the only dissolved silica is an hypothesis which is not verified for the greater part of the glasses. (O.L.). refs., figs

High-silica glass matrix process for high-level waste solidification

International Nuclear Information System (INIS)

Simmons, J.H.; Macedo, P.B.

1981-01-01

In the search for an optimum glass matrix composition, we have determined that chemical durability and thermal stability are maximized, and that stress development is minimized for glass compositions containing large concentrations of glass-forming oxides, of which silica is the major component (80 mol%). These properties and characteristics were recently demonstrated to belong to very old geological glasses known as tektites (ages of 750,000 to 34 million years.) The barrier to simulating tektite compositions for the waste glasses was the high melting temperature (1600 to 1800 0 C) needed for these glasses. Such temperatures greatly complicate furnace design and maintenance and lead to an intolerable vaporization of many of the radioisotopes into the off-gas system. Research conducted at our laboratory led to the development of a porous high-silica waste glass material with approximately 80% SiO 2 by mole and 30% waste loading by weight. The process can handle a wide variety of compositions, and yields long, elliptical, monolithic samples, which consist of a loaded high-silica core completely enveloped in a high-silica glass tube, which has collapsed upon the core and sealed it from the outside. The outer glass layer is totally free of waste isotopes and provides an integral multibarrier protection system

Celsian Glass-Ceramic Matrix Composites

Science.gov (United States)

Bansal, Narottam P.; Dicarlo, James A.

1996-01-01

Glass-ceramic matrix reinforced fiber composite materials developed for use in low dielectric applications, such as radomes. Materials strong and tough, exhibit low dielectric properties, and endure high temperatures.

Evaluation of titanium carbide metal matrix composites deposited via laser cladding

Science.gov (United States)

Cavanaugh, Daniel Thomas

Metal matrix composites have been widely studied in terms of abrasion resistance, but a particular material system may behave differently as particle size, morphology, composition, and distribution of the hardening phase varies. The purpose of this thesis was to understand the mechanical and microstructural effects of combining titanium carbide with 431 series stainless steel to create a unique composite via laser cladding, particularly regarding wear properties. The most predominant effect in increasing abrasion resistance, measured via ASTM G65, was confirmed to be volume fraction of titanium carbide addition. Macrohardness was directly proportional to the amount of carbide, though there was an overall reduction in individual particle microhardness after cladding. The reduction in particle hardness was obscured by the effect of volume fraction carbide and did not substantially contribute to the wear resistance changes. A model evaluating effective mean free path of the titanium carbide particles was created and correlated to the measured data. The model proved successful in linking theoretical mean free path to overall abrasion resistance. The effects of the titanium carbide particle distributions were limited, while differences in particle size were noticeable. The mean free path model did not correlate well with the particle size, but it was shown that the fine carbides were completely removed by the coarse abrasive particles in the ASTM G65 test. The particle morphology showed indications of influencing the wear mode, but no statistical reduction was observed in the volume loss figures. Future studies may more specifically focus on particle morphology or compositional effects of the carbide particles.

Study of optical properties of Erbium doped Tellurite glass-polymer composite

Science.gov (United States)

Sushama, D.

2014-10-01

Chalcogenide glasses have wide applications in optical device technology. But it has some disadvantages like thermal instability. Among them Tellurite glasses exhibits high thermal Stability. Doping of rare earth elements into the Tellurite glasses improve its optical properties. To improve its mechanical properties composites of this Tellurite glasses with polymer are prepared. Bulk samples of Er2O3 doped TeO2-WO3-La2O3 Tellurite glasses are prepared from high purity oxide mixtures, melting in an alumina crucible in air atmosphere. Composites of this Tellurite glasses with polymer are prepared by powder mixing method and the thin films of these composites are prepared using polymer press. Variations in band gap of these composites are studied from the UV/Vis/NIR absorption.

Near net-shape fabrication of hydroxyapatite glass composites

NARCIS (Netherlands)

Zhu, Q.; With, de G.; Dortmans, L.; Feenstra, F.

2004-01-01

Near net-shape fabrication of hydroxyapatite (HA) glass composites has been attempted by infiltrating a glass into porous HA performs. Main efforts were put to develop glasses that are chemically compatible with HA at elevated temperatures. After extensive investigations in the phosphate and

Effect of glass composition on waste form durability: A critical review

International Nuclear Information System (INIS)

Ellison, A.J.G.; Mazer, J.J.; Ebert, W.L.

1994-11-01

This report reviews literature concerning the relationship between the composition and durability of silicate glasses, particularly glasses proposed for immobilization of radioactive waste. Standard procedures used to perform durability tests are reviewed. It is shown that tests in which a low-surface area sample is brought into contact with a very large volume of solution provide the most accurate measure of the intrinsic durability of a glass composition, whereas high-surface area/low-solution volume tests are a better measure of the response of a glass to changes in solution chemistry induced by a buildup of glass corrosion products. The structural chemistry of silicate and borosilicate glasses is reviewed to identify those components with the strongest cation-anion bonds. A number of examples are discussed in which two or more cations engage in mutual bonding interactions that result in minima or maxima in the rheologic and thermodynamic properties of the glasses at or near particular optimal compositions. It is shown that in simple glass-forming systems such interactions generally enhance the durability of glasses. Moreover, it is shown that experimental results obtained for simple systems can be used to account for durability rankings of much more complex waste glass compositions. Models that purport to predict the rate of corrosion of glasses in short-term durability tests are evaluated using a database of short-term durability test results for a large set of glass compositions. The predictions of these models correlate with the measured durabilities of the glasses when considered in large groupings, but no model evaluated in this review provides accurate estimates of durability for individual glass compositions. Use of these models in long-term durability models is discussed. 230 refs

Improving subcritical crack growth resistance for alumina glass dental composite

NARCIS (Netherlands)

Zhu, Q.; With, de G.

2005-01-01

The improvement of subcritical crack growth (SCG) resistance for alumina glass dental composites was explored in this study. The addition of nitrogen to the glass phases in the composite was found to increase the SCG resistance, where the SCG exponent n increases from 22 for the oxide glass

Development, characterisation and biocompatibility testing of a cobalt-containing titanium phosphate-based glass for engineering of vascularized hard tissues

Energy Technology Data Exchange (ETDEWEB)

Lee, In-Ho [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Yu, Hye-sun [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Department of Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom); Lakhkar, Nilay J. [Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, 256 Gray' s Inn Road, London WC1X 8LD (United Kingdom); Kim, Hae-Won [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Gong, Myoung-Seon [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Knowles, Jonathan C. [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, 256 Gray' s Inn Road, London WC1X 8LD (United Kingdom); Wall, Ivan B., E-mail: i.wall@ucl.ac.uk [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Department of Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom)

2013-05-01

There is a continuing need to develop scaffold materials that can promote vascularisation throughout the tissue engineered construct. This study investigated the effect of cobalt oxide (CoO) doped into titanium phosphate glasses on material properties, biocompatibility and vascular endothelial growth factor (VEGF) secretion by osteoblastic MG63 cells. Glasses composed of (P{sub 2}O{sub 5}){sub 45}(Na{sub 2}O){sub 20}(TiO{sub 2}){sub 05}(CaO){sub 30−x}(CoO){sub x}(x = 0, 5, 10, and 15 mol%) were fabricated and the effect of Co on physicochemical properties including density, glass transition temperature (T{sub g}), degradation rate, ion release, and pH changes was assessed. The results showed that incorporation of CoO into the glass system produced an increase in density with little change in T{sub g}. It was then confirmed that the pH did not change significantly when CoO was incorporated in the glass, and stayed constant at around 6.5–7.0 throughout the dissolution study period of 336 h. Ion release results followed a specific pattern with increasing amounts of CoO. In general, although incorporation of CoO into a titanium phosphate glass increased its density, other bulk and surface properties of the glass did not show any significant changes. Cell culture studies performed using MG63 cells over a 7-day period indicated that the glasses provide a stable surface for cell attachment and are biocompatible. Furthermore, VEGF secretion was significantly enhanced on all glasses compared with standard tissue culture plastic and Co doping enhanced this effect further. In conclusion, the developed Co-doped glasses are stable and biocompatible and thus offer enhanced potential for engineering vascularized tissue. - Highlights: ► Phosphate-based glasses can be successfully doped with cobalt oxide. ► The resulting glass is highly stable with low degradation rate. ► Co-doped glasses are biocompatible but do not favour cell proliferation. ► Osteoblastic MG63 cells

Processing glass-pyrochlore composites for nuclear waste encapsulation

International Nuclear Information System (INIS)

Pace, S.; Cannillo, V.; Wu, J.; Boccaccini, D.N.; Seglem, S.; Boccaccini, A.R.

2005-01-01

Glass matrix composites have been developed as alternative materials to immobilize nuclear solid waste, in particular actinides. These composites are made of soda borosilicate glass matrix, into which particles of lanthanum zirconate pyrochlore are encapsulated in concentrations of 30 vol.%. The fabrication process involves powder mixing followed by hot-pressing. At the relatively low processing temperature used (620 deg. C), the pyrochlore crystalline structure of the zirconate, which is relevant for containment of radioactive nuclei, remains unaltered. The microstructure of the composites exhibits a homogeneous distribution of isolated pyrochlore particles in the glass matrix and strong bonding at the matrix-particle interfaces. Hot-pressing was found to lead to high densification (95% th.d.) of the composite. The materials are characterized by relatively high elastic modulus, flexural strength, hardness and fracture toughness. A numerical approach using a microstructure-based finite element solver was used in order to investigate the mechanical properties of the composites

Investigating the solubility and cytocompatibility of CaO-Na2 O-SiO2 /TiO2 bioactive glasses.

Science.gov (United States)

Wren, Anthony W; Coughlan, Aisling; Smith, Courtney M; Hudson, Sarah P; Laffir, Fathima R; Towler, Mark R

2015-02-01

This study aims to investigate the solubility of a series of titanium (TiO2 )-containing bioactive glasses and their subsequent effect on cell viability. Five glasses were synthesized in the composition range SiO2 -Na2 O-CaO with 5 mol % of increments TiO2 substituted for SiO2 . Glass solubility was investigated with respect to (1) exposed surface area, (2) particle size, (3) incubation time, and (4) compositional effects. Ion release profiles showed that sodium (Na(+) ) presented high release rates after 1 day and were unchanged between 7 and 14 days. Calcium (Ca(2+) ) release presented a significant change at each time period and was also composition dependent, where a reduction in Ca(2+) release is observed with an increase in TiO2 concentration. Silica (Si(4+) ) release did not present any clear trends while no titanium (Ti(4+) ) was released. Cell numbers were found to increase up to 44%, compared to the growing control population, with a reduction in particle size and with the inclusion of TiO2 in the glass composition. © 2014 Wiley Periodicals, Inc.

Study of optical properties of Erbium doped Tellurite glass-polymer composite

Energy Technology Data Exchange (ETDEWEB)

Sushama, D., E-mail: sushasukumar@gmail.com [Research Awardee, LAMP, Dept. of Physics, Nit, Calicut, India and Dept. of Physics, M.S.M. College, Kayamkulam, Kerala (India)

2014-10-15

Chalcogenide glasses have wide applications in optical device technology. But it has some disadvantages like thermal instability. Among them Tellurite glasses exhibits high thermal Stability. Doping of rare earth elements into the Tellurite glasses improve its optical properties. To improve its mechanical properties composites of this Tellurite glasses with polymer are prepared. Bulk samples of Er{sub 2}O{sub 3} doped TeO{sub 2}‐WO{sub 3}‐La{sub 2}O{sub 3} Tellurite glasses are prepared from high purity oxide mixtures, melting in an alumina crucible in air atmosphere. Composites of this Tellurite glasses with polymer are prepared by powder mixing method and the thin films of these composites are prepared using polymer press. Variations in band gap of these composites are studied from the UV/Vis/NIR absorption.

Study of optical properties of Erbium doped Tellurite glass-polymer composite

International Nuclear Information System (INIS)

Sushama, D.

2014-01-01

Chalcogenide glasses have wide applications in optical device technology. But it has some disadvantages like thermal instability. Among them Tellurite glasses exhibits high thermal Stability. Doping of rare earth elements into the Tellurite glasses improve its optical properties. To improve its mechanical properties composites of this Tellurite glasses with polymer are prepared. Bulk samples of Er 2 O 3 doped TeO 2 ‐WO 3 ‐La 2 O 3 Tellurite glasses are prepared from high purity oxide mixtures, melting in an alumina crucible in air atmosphere. Composites of this Tellurite glasses with polymer are prepared by powder mixing method and the thin films of these composites are prepared using polymer press. Variations in band gap of these composites are studied from the UV/Vis/NIR absorption

Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant.

Science.gov (United States)

Petersen, Richard C

2011-05-03

Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P engineering potential.

Evaluation of Force-Time Changes During Impact of Hybrid Laminates Made of Titanium and Fibrous Composite

Directory of Open Access Journals (Sweden)

Jakubczak P.

2016-06-01

Full Text Available Fibre metal laminates (FML are the modern hybrid materials with potential wide range of applications in aerospace technology due to their excellent mechanical properties (particularly fatigue strength, resistance to impacts and also excellent corrosion resistance. The study describes the resistance to low velocity impacts in Ti/CFRP laminates. Tested laminates were produced in autoclave process. The laminates were characterized in terms of their response to impacts in specified energy range (5J, 10J, 20J. The tests were performed in accordance with ASTM D7137 standard. The laminates were subjected to impacts by means of hemispherical impactor with diameter of 12,7 mm. The following values have been determined: impact force vs. time, maximum force and the force at which the material destruction process commences (Pi. It has been found that fibre titanium laminates are characterized by high resistance to impacts. This feature is associated with elasto-plastic properties of metal and high rigidity of epoxy - fibre composite. It has been observed that Ti/CFRP laminates are characterized by more instable force during impact in stage of stabilization of impactor-laminate system and stage of force growth that glass fibre laminates. It has been observed more stable force decrease in stage of stress relaxation and withdrawal of the impactor. In energy range under test, the laminates based on titanium with glass and carbon fibres reinforcement demonstrate similar and high resistance to low-velocity impact, measured by means of failure initiation force and impact maximum force.

Thermoset composite recycling: Properties of recovered glass fiber

DEFF Research Database (Denmark)

Beauson, Justine; Fraisse, Anthony; Toncelli, C.

2015-01-01

Recycling of glass fiber thermoset polymer composite is a challenging topic and a process able to recover the glass fibers original properties in a limited cost is still under investigation. This paper focuses on the recycling technique separating the glass fiber from the matrix material. Four...

SEALING ABILITY OF MINERAL TRIOXIDE AGGREGATE, CALCIUM PHOSPHATE CEMENT, AND GLASS IONOMER CEMENT IN THE REPAIR OF FURCATION PERFORATIONS

Directory of Open Access Journals (Sweden)

Prabath Singh

2013-01-01

Full Text Available Objectives: The purpose of this study was to evaluate the in vitro sealing ability of three repair materials. Mineral trioxide aggregate (MTA; Group A, calcium phosphate cement (CPC; Group B, and light cured glass ionomer cement (GIC; Group C when used to repair the perforation created in the pulpal floor of fifty extracted human permanent molars. Materials and methods: Preparation of access openings and furcation perforations were done, and the teeth divided into five experimental groups (A, B, C including two controls (D, E with ten samples in each group randomly. Following the repair procedure, the pulp chambers and access openings were filled with composite resin and immersed in 2% methylene blue solution for 48 hours. The teeth were sectioned longitudinally and the linear dye penetration measured under a stereo­microscope. Results: The comparison of the linear length of micro-leakage (mm among the experimental groups revealed no significant difference (p = 0.332. On calculating the percentage of depth of leakage to the total length of the perforation, it was observed that the mean leakage was 35.5% in Group A, 53.6% in Group B and the highest, 87.5% in Group C. The mean of leakage percentage was statistically significant by Kruskal-Wallis test (p = 0.003. The results indicated that the dye penetration used as furcation perforation repair material was least with mineral trioxide aggregate. Comparing the depth of penetration of dye, 50% of the Group A samples showed less than 25% of depth penetration. While 40% of Group B cases had more than 50% dye penetration. In our study, all Group C teeth had ≥ 50% dye penetration. Conclusions: The present study indicated that GIC had the greatest dye penetration followed by CPC and MTA. Mineral trioxide aggregate and calcium phosphate cement had comparatively better sealing ability than glass ionomer cement.

Structure of organometallic compounds obtained by plasma of titanium isopropoxide

International Nuclear Information System (INIS)

Arreola R, M. L.

2012-01-01

This work presents a study on the synthesis and characterization of organometallic compounds of titanium oxide obtained from glow discharges of titanium tetraisopropoxide (TTIP) and water on glass and polyethylene. The objective is the synthesis of titanium oxide particles which can be fixed on different supports for use in further studies of contaminants degradation in effluent streams. The synthesis was carried out by plasma in a glass tubular reactor of 750 cm 3 and 15 cm length at 10 -1 mbar with power between 100 and 150 W during 2, 3 and 4 h. The precursors were TTIP and water vapor. TTIP is an organometallic compound composed of a central atom of Ti surrounded by 4 O atoms, which in turn are connected with chains of 3 C (propane s). The objective is the use of plasma collisions to separate the organic and inorganic phases of TTIP, so that both structure independently in a single material. The result was the formation of white titanium oxide powder composed with agglomerates of spherical particles with average diameter between 160 and 452 nm adhered to small films. The agglomerates have a tendency to change from film to particles with the energy applied to the synthesis. The study of the chemical structure showed a great presence of O 2 -Ti-O 2 (Ti surrounded by O) which can be found in most titanium oxides. Other chemical groups belonging to the organic phase were C=C=C, C=C=O and C 2 -C-Ch appearing from the dehydrogenation of TTIP, which can be a possible precursor of this reactions kind. The structural superficial analyses showed that the atomic composition varies according to type of substrate used. The greatest content of Ti was obtained on glass substrates. However, the synthesis conditions had not evident effect in the participation of chemical states found in the inorganic phase. The crystalline studies indicated that the material is amorphous, although the de convoluted X-ray spectra showed that the synthesized titanium oxides on glass tend to

Damage characterization of E-glass and C-glass fibre polymer composites after high velocity impact

Science.gov (United States)

Razali, N.; Sultan, M. T. H.; Cardona, F.; Jawaid, M.

2017-12-01

The purpose of this work is to identify impact damage on glass fibre reinforced polymer composite structures after high velocity impact. In this research, Type C-glass (600 g/m2) and Type E-glass (600 g/m2) were used to fabricate Glass Fibre-Reinforced Polymer composites (GFRP) plates. The panels were fabricated using a vacuum bagging and hot bounder method. Single stage gas gun (SSGG) was used to do the testing and data acquisition system was used to collect the damage data. Different types of bullets and different pressure levels were used for the experiment. The obtained results showed that the C-glass type of GFRP experienced more damage in comparison to E-glass type of materials based on the amount of energy absorbed on impact and the size of the damage area. All specimens underwent a partial fibre breakage but the laminates were not fully penetrated by the bullets. This indicated that both types of materials have high impact resistance even though the applied pressures of the gas gun were on the high range. We concluded that within the material specifications of the laminates including the type of glass fibre reinforcement and the thickness of the panels, those composite materials are safe to be applied in structural and body armour applications as an alternative to more expensive materials such as Kevlar and type S-glass fibre based panels.

Non-toxic invert analog glass compositions of high modulus

Science.gov (United States)

Bacon, J. F. (Inventor)

1974-01-01

Glass compositions having a Young's modulus of at least 15 million psi are described. They and a specific modulus of at least 110 million inches consist essentially of, in mols, 15 to 40% SiO2, 6 to 15% Li2O, 24 to 45% of at least two bivalent oxides selected from the group consisting of Ca, NzO, MgO and CuO; 13 to 39% of at least two trivalent oxides selected from the group consisting of Al2O3, Fe2O3, B2O3, La2O3, and Y2O3 and up to 15% of one or more tetravelent oxides selected from the group consisting of ZrO2, TiO2 and CeO2. The high modulus, low density glass compositions contain no toxic elements. The composition, glass density, Young's modulus, and specific modulus for 28 representative glasses are presented. The fiber modulus of five glasses are given.

ASTM and VAMAS activities in titanium matrix composites test methods development

Science.gov (United States)

Johnson, W. S.; Harmon, D. M.; Bartolotta, P. A.; Russ, S. M.

1994-01-01

Titanium matrix composites (TMC's) are being considered for a number of aerospace applications ranging from high performance engine components to airframe structures in areas that require high stiffness to weight ratios at temperatures up to 400 C. TMC's exhibit unique mechanical behavior due to fiber-matrix interface failures, matrix cracks bridged by fibers, thermo-viscoplastic behavior of the matrix at elevated temperatures, and the development of significant thermal residual stresses in the composite due to fabrication. Standard testing methodology must be developed to reflect the uniqueness of this type of material systems. The purpose of this paper is to review the current activities in ASTM and Versailles Project on Advanced Materials and Standards (VAMAS) that are directed toward the development of standard test methodology for titanium matrix composites.

Subcritical crack growth behavior of AI2O3-Glass dental composites

NARCIS (Netherlands)

Zhu, Q.; With, G. de; Dortmans, L.J.M.G.; Feenstra, F.

2003-01-01

The purpose of this study is to investigate the subcritical crack growth (SCG) behavior of alumina-glass dental composites. Alumina-glass composites were fabricated by infiltrating molten glass to porous alumina preforms. Rectangular bars of the composite were subject to dynamic loading in air, with

GLASS-FIBRE REINFORCED COMPOSITES: THE EFFECT OF ...

African Journals Online (AJOL)

HOD

mechanical and corrosion wear behaviour of any reinforced composites. In other ..... physical properties of glass fibre reinforced epoxy resin and the following .... waste in concrete and cement composites," Journal of Cleaner Production, vol.

Selection of a glass-ceramic formulation to immobilize fluorinel- sodium calcine

International Nuclear Information System (INIS)

Staples, B.A.; Wood, H.C.

1994-12-01

One option for immobilizing calcined high level wastes produced by nuclear fuel reprocessing activities at the Idaho Chemical Processing Plant (ICPP) is conversion to a glass-ceramic form through hot isostatic pressing. Calcines exist in several different chemical compositions, and thus candidate formulations have been developed for converting each to glass-ceramic forms which are potentially resistant to aqueous corrosion and stable enough to qualify for repository storage. Fluorinel/Na, a chemically complex calcine type, is one of the types being stored at ICPP, and development efforts have identified three formulations with potential for immobilizing it. These are a glass forming additive that uses aluminum metal to enhance reactivity, a second glass forming additive that uses titanium metal to enhance reactivity and a third that uses not only a combination of silicon and titanium metals but enough phosphorous pentoxide to form a calcium phosphate host phase in the glass-ceramic product. Glass-ceramics of each formulation performed well in restricted characterization tests. However, none of the three was subjected to rigorous testing that would provide information on whether each was processable, that is able to retain favorable characteristics over a practical range of processing conditions

Defining the Glass Composition Limits for SRS Contaminated Soils

International Nuclear Information System (INIS)

Cicero, C.A.; Bickford, D.F.; Crews, W.O.

1995-01-01

Contaminated soil resulting from the excavation, repair, and decommissioning of facilities located at the Savannah River Site (SRS) is currently being disposed of by shallow land burial or is being stored when considered only hazardous. Vitrification of this waste is being investigated, since it will bind the hazardous and radioactive species in a stable and durable glass matrix, which will reduce the risk of ground water contamination. However, the composition limits for producing durable glass have to be determined before the technology can be applied. Glass compositions, consisting of SRS soil and glass forming additives, were tested on a crucible-scale in three ternary phase systems. Nine different glass compositions were produced, with waste loadings ranging from 43 to 58 weight percent. These were characterized using varoius chemical methods and tested for durability in both alkaline and acidic environments. All nine performed well in alkaline environments, but only three met the strictest criteria for the acidic environment tests. Although the glasses did not meet all of the limits for the acidic tests, the test was performed on very conservative size samples, so the results were also conservative. Therefore, enough evidence was found to provide proof that SRS soil can be vitrified in a durable glass matrix

Scanning Auger microscopy study of lanthanum partitioning in sphene-based glass-ceramics

International Nuclear Information System (INIS)

Hocking, W.H.; Hayward, P.J.; Watson, D.G.; Allen, G.C.

1984-01-01

Glass-ceramics are being investigated as possible hosts for the radioactive wastes that would result from recycling irradiated nuclear fuels. The partitioning of lanthanum in sphene-based glass-ceramics has been studied by scanning Auger electron microscopy for lanthanum concentrations from 0.2 to 2.0 mol.%. Sphene crystals (CaTiSiO 5 ) were located in the silica-rich glass matrix by recording digital Auger images of the calcium and titanium distributions. The sphene crystals were typically 0.5 to 5 μm in size and occupied approximately 40% of the total specimen volume. Auger spot analyses revealed that lanthanum was strongly partitioned into the sphene phase of phosphorus-free glass-ceramics; however, when a small amount of phosphorus was included in the glass-ceramic composition as a crystal nucleating agent, the lanthanum was concentrated in a third minor phase which also contained calcium, phosphorus and oxygen. Chemical shift effects in the Auger spectra of silicon, titanium and phosphorus showed evidence for electron-stimulated desorption of oxygen. (author)

Development of glass/glass-ceramics materials and devices and their micro-structural studies

International Nuclear Information System (INIS)

Goswami, Madhumita; Sarkar, Arjun; Shingarvelan, Shobha; Kumar, Rakesh; Ananathanarayan, Arvind; Shrikhande, V.K.; Kothiyal, G.P.

2009-01-01

Materials and devices based on glass and glass-ceramics (GCs) find applications in various high pressure and vacuum applications. We have prepared different glasses/glass-ceramics with requisite thermal expansion coefficient, electrical, vacuum and wetting characteristics to fabricate hermetic seals with different metals/alloys as well as components for these applications. Some of these are, SiO 2 -Na 2 O-K 2 O-Al 2 O 3 -B 2O3 (BS) for matched type of seal fabricated with Kovar alloy, SiO 2 -Na 2 O-K 2 O-BaO-PbO(LS) for fabrication of compressive type seals with stainless steel and SS 446 alloys, P 2 O 5 -Na 2 O-B 2 O 3 -BaO-PbO(NAP) for fabrication of matched type of seal with relatively low melting metals/alloys like AI/Cu-Be and Li 2 O-ZnO-SiO 2 -P 2 O 5 -B 2 O 3 -Na 2 O (LZS) and Lithium aluminium silicate (LAS) glass-ceramics to fabricate matched and compression types feedtroughs/conductivity probes Magnesium aluminium silicate (MAS) machinable glass-ceramics is another development for high voltage and ultra high vacuum applications. Micro-structural studies have been carried out on these materials to understand the mechanism of their behaviour and have also been deployed in various systems and plants in DAE. (author)

Physicochemical properties of discontinuous S2-glass fiber reinforced resin composite.

Science.gov (United States)

Huang, Qiting; Qin, Wei; Garoushi, Sufyan; He, Jingwei; Lin, Zhengmei; Liu, Fang; Vallittu, Pekka K; Lassila, Lippo V J

2018-01-30

The objective of this study was to investigate several physicochemical properties of an experimental discontinuous S2-glass fiber-reinforced resin composite. The experimental composite was prepared by mixing 10 wt% of discontinuous S2-glass fibers with 27.5 wt% of resin matrix and 62.5 wt% of particulate fillers. Flexural strength (FS) and modulus (FM), fracture toughness (FT), work of fracture (WOF), double bond conversion (DC), Vickers hardness, volume shrinkage (VS) and fiber length distribution were determined. These were compared with two commercial resin composites. The experimental composite showed the highest FS, WOF and FT compared with two control composites. The DC of the experimental composite was comparable with controls. No significant difference was observed in VS between the three tested composites. The use of discontinuous glass fiber fillers with polymer matrix and particulate fillers yielded improved physical properties and substantial improvement was associated with the use of S2-glass fiber.

Production of continuous glass fiber using lunar simulant

Science.gov (United States)

Tucker, Dennis S.; Ethridge, Edwin C.; Curreri, Peter A.

1991-01-01

The processing parameters and mechanical properties of glass fibers pulled from simulated lunar basalt are tested. The simulant was prepared using a plasma technique. The composition is representative of a low titanium mare basalt (Apollo sample 10084). Lunar gravity experiments are to be performed utilizing parabolic aircraft free-fall maneuvers which yield 30 seconds of 1/6-g per maneuver.

Barium oxide, calcium oxide, magnesia, and alkali oxide free glass

Science.gov (United States)

Lu, Peizhen Kathy; Mahapatra, Manoj Kumar

2013-09-24

A glass composition consisting essentially of about 10-45 mole percent of SrO; about 35-75 mole percent SiO.sub.2; one or more compounds from the group of compounds consisting of La.sub.2O.sub.3, Al.sub.2O.sub.3, B.sub.2O.sub.3, and Ni; the La.sub.2O.sub.3 less than about 20 mole percent; the Al.sub.2O.sub.3 less than about 25 mole percent; the B.sub.2O.sub.3 less than about 15 mole percent; and the Ni less than about 5 mole percent. Preferably, the glass is substantially free of barium oxide, calcium oxide, magnesia, and alkali oxide. Preferably, the glass is used as a seal in a solid oxide fuel/electrolyzer cell (SOFC) stack. The SOFC stack comprises a plurality of SOFCs connected by one or more interconnect and manifold materials and sealed by the glass. Preferably, each SOFC comprises an anode, a cathode, and a solid electrolyte.

Photocatalytic activity of titanium dioxide modified concrete materials - influence of utilizing recycled glass cullets as aggregates.

Science.gov (United States)

Chen, Jun; Poon, Chi-Sun

2009-08-01

Combining the use of photocatalysts with cementitious materials is an important development in the field of photocatalytic air pollution mitigation. This paper presents the results of a systematic study on assessing the effectiveness of pollutant degradation by concrete surface layers that incorporate a photocatalytic material - Titanium Dioxide. The photocatalytic activity of the concrete samples was determined by photocatalytic oxidation of nitric oxide (NO) in the laboratory. Recycled glass cullets, derived from crushed waste beverage bottles, were used to replace sand in preparing the concrete surface layers. Factors, which may affect the pollutant removal performance of the concrete layers including glass color, aggregate size and curing age, were investigated. The results show a significant enhancement of the photocatalytic activity due to the use of glass cullets as aggregates in the concrete layers. The samples fabricated with clear glass cullets exhibited threefold NO removal efficiency compared to the samples fabricated with river sand. The light transmittance property of glass was postulated to account for the efficiency improvement, which was confirmed by a separate simulation study. But the influence of the size of glass cullets was not evident. In addition, the photocatalytic activity of concrete surface layers decreased with curing age, showing a loss of 20% photocatalytic activity after 56-day curing.

Strontium chloroapatite based glass-ceramics composites for nuclear waste immobilisation

International Nuclear Information System (INIS)

Jena, Hrudananda; Maji, Binoy Kumar; Asuvathraman, R.; Govindan Kutty, K.V.

2013-01-01

Apatites are naturally occurring minerals with a general formula of M 10 (PO 4 ) 6 X 2 , (M= Ca, Sr, Ba, X= OH, Cl, F) with a hexagonal crystal structure (S.G :P6 3 /m) and can accommodate alkaline earth and various other aliovalent cations and anions into its crystal structure. Apatites are also known to have high resistance to leaching of the constituent elements under geological conditions. It may not often be possible to immobilize the whole spectrum of the radioactive waste in a single phase M 10 (PO 4 ) 6 Cl 2 , then a combination of M-chloroapatite encapsulated in borosilicate glass (BSG) can immobilize most of the radwaste elements in the composite glass-ceramic matrix (glass bonded chloroapatite), thus utilizing the immobilizing efficiency of both the ceramic phase and glass. In the present study, the synthesis, characterization and thermo-physical property measurements of the Sr-chloroapatite (SrApCI) and some glass-bonded composites based on it have been investigated. The Sr-chloroapatite glass-ceramics were prepared by solid state reactions among stoichiometric concentrations of apatite forming reagents, 20 wt. % borosilicate glass (BSG), and known concentrations (10, 13 and 16 wt. %) of a simulated waste in chloride form. The products were characterized by XRD to confirm the formation of Sr 10 (PO 4 ) 6 Cl 2 and glass bonded-chloroapatite composites. The surface morphology and qualitative chemical composition of the powders were examined by SEM and EDX. Thermal expansion and glass transition temperature of the matrices were measured by dilatometry. Glass transition temperature of the glass-bonded composites was also examined by differential scanning calorimetry and differential thermal analysis. The 10-16 wt.% waste loaded matrices showed similar thermal expansion as that of SrApCI, indicating the thermal stability of the matrix to chloride waste immobilization. The glass transition temperature of the waste loaded matrices decreases on increasing the

Effect of the metallic glass volume fraction on the mechanical properties of Zr-based metallic glass reinforced with porous W composite

International Nuclear Information System (INIS)

Zhang, X.Q.; Wang, L.; Xue, Y.F.; Cheng, X.W.; Wang, Y.D.; Nie, Z.H.; Zhang, H.F.; Fu, H.M.; Ma, L.L.; Ren, Y.

2013-01-01

The mechanical properties of both as-cast and as-extruded Zr-based metallic glass reinforced with tungsten composites with 33, 28, and 21 vol. % of metallic glass were investigated under quasi-static compression at strain rates from 10 −4 s −1 to 10 −1 s −1 . These two types of composites exhibited a strain rate sensitivity exponent that increased with the increase of the tungsten volume fraction. Compared to the composites with 33 and 21 vol. % of the metallic glass, the two types of composites with 28 vol. % of the metallic glass phase exhibited superior fracture energies. The in-situ compression test on the as-cast composites using high-energy synchrotron X-ray diffraction (HEXRD) revealed that the yield stress of the tungsten phase increased with a decrease in the metallic glass volume fraction. The as-cast composite with 28 vol. % of the metallic glass exhibited relatively great mechanical properties compared to the composites that contained 33 and 21 vol. % of the metallic glass. This result was attributed to the great coupling of the load distribution between the two phases and the high lattice strain in the tungsten phase.

Characteristics of diffusion zone in changing glass-metal composite processing conditions

Science.gov (United States)

Lyubimova, O. N.; Morkovin, A. V.; Andreev, V. V.

2018-03-01

The influence of manufacturing technology on the characteristics of the glass and steel contact zone in manufacturing new structural material - glass-metal composite is studied theoretically and experimentally. Different types of structures in the contact zone and its dimensions affect the strength characteristics of the composite. Knowledge about changing the width of the glass and steel contact zone after changing such parameters of the technological regime as temperature, holding time and use of solders will allow one to control the structure and characteristics of the glass-metal composite. Experimental measurements of the width of the diffusion zone in the glass-metal composite for different regimes and their statistical processing according to the full factor experiment are presented in this article. The results of analysis of some mechanical characteristics of the diffusion zone are presented: microhardness and modulus of elasticity for samples, prepared according to different processing regimes.

Systematic approach to preparing ceramic-glass composites with high translucency for dental restorations.

Science.gov (United States)

Yoshimura, Humberto N; Chimanski, Afonso; Cesar, Paulo F

2015-10-01

Ceramic composites are promising materials for dental restorations. However, it is difficult to prepare highly translucent composites due to the light scattering that occurs in multiphase ceramics. The objective of this work was to verify the effectiveness of a systematic approach in designing specific glass compositions with target properties in order to prepare glass infiltrated ceramic composites with high translucency. First it was necessary to calculate from literature data the viscosity of glass at the infiltration temperature using the SciGlass software. Then, a glass composition was designed for targeted viscosity and refractive index. The glass of the system SiO2-B2O3-Al2O3-La2O3-TiO2 prepared by melting the oxide raw materials was spontaneously infiltrated into porous alumina preforms at 1200°C. The optical properties were evaluated using a refractometer and a spectrophotometer. The absorption and scattering coefficients were calculated using the Kubelka-Munk model. The light transmittance of prepared composite was significantly higher than a commercial ceramic-glass composite, due to the matching of glass and preform refractive indexes which decreased the scattering, and also to the decrease in absorption coefficient. The proposed systematic approach was efficient for development of glass infiltrated ceramic composites with high translucency, which benefits include the better aesthetic performance of the final prosthesis. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Preparation and bioactive properties of nano bioactive glass and segmented polyurethane composites.

Science.gov (United States)

Aguilar-Pérez, Fernando J; Vargas-Coronado, Rossana F; Cervantes-Uc, Jose M; Cauich-Rodríguez, Juan V; Covarrubias, Cristian; Pedram-Yazdani, Merhdad

2016-04-01

Composites of glutamine-based segmented polyurethanes with 5 to 25 wt.% bioactive glass nanoparticles were prepared, characterized, and their mineralization potential was evaluated in simulated body fluid. Biocompatibility with dental pulp stem cells was assessed by MTS to an extended range of compositions (1 to 25 wt.% of bioactive glass nanoparticles). Physicochemical characterization showed that composites retained many of the matrix properties, i.e. those corresponding to semicrystalline elastomeric polymers as they exhibited a glass transition temperature (Tg) between -41 and -36℃ and a melting temperature (Tm) between 46 and 49℃ in agreement with X-ray reflections at 23.6° and 21.3°. However, with bioactive glass nanoparticles addition, tensile strength and strain were reduced from 22.2 to 12.2 MPa and 667.2 to 457.8%, respectively with 25 wt.% of bioactive glass nanoparticles. Although Fourier transform infrared spectroscopy did not show evidence of mineralization after conditioning of these composites in simulated body fluid, X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray microanalysis showed the formation of an apatite layer on the surface which increased with higher bioactive glass concentrations and longer conditioning time. Dental pulp stem cells proliferation at day 5 was improved in bioactive glass nanoparticles composites containing lower amounts of the filler (1-2.5 wt.%) but it was compromised at day 9 in composites containing high contents of nBG (5, 15, 25 wt.%). However, Runx2 gene expression was particularly upregulated for the dental pulp stem cells cultured with composites loaded with 15 and 25 wt.% of bioactive glass nanoparticles. In conclusion, low content bioactive glass nanoparticles and segmented polyurethanes composites deserve further investigation for applications such as guided bone regeneration membranes, where osteoconductivity is desirable but not a demanding mechanical performance. © The

First principles process-product models for vitrification of nuclear waste: Relationship of glass composition to glass viscosity, resistivity, liquidus temperature, and durability

International Nuclear Information System (INIS)

Jantzen, C.M.

1991-01-01

Borosilicate glasses will be used in the USA and in Europe to immobilize radioactive high level liquid wastes (HLLW) for ultimate geologic disposal. Process and product quality models based on glass composition simplify the fabrication of the borosilicate glass while ensuring glass processability and quality. The process model for glass viscosity is based on a relationship between the glass composition and its structural polymerization. The relationship between glass viscosity and electrical resistivity is also shown to relate to glass polymerization. The process model for glass liquidus temperature calculates the solubility of the liquidus phases based on the free energies of formation of the precipitating species. The durability product quality model is based on the calculation of the thermodynamic hydration free energy from the glass composition

Near net-shape fabrication of alumina glass composites

NARCIS (Netherlands)

Zhu, Q.; With, de G.; Dortmans, L.J.M.G.; Feenstra, F.

2005-01-01

The purpose of the present study is to fabricate alumina glass composites by melt infiltration with better dimensional control through reducing both the presintering and infiltration temperature. Main efforts were put to develop glasses that are chemically compatible with alumina. After extensive

Mechanical, dielectric and optical assessment of glass composites ...

Indian Academy of Sciences (India)

The band gap, Urbach energy and the extinction coefficient of the glass composites have been ... icate glasses during our previous studies.7 Lanthanum oxide. (La2O3) .... vs. incident photon energy hν are used to determine the type of optical ...

Investigation of sizing - from glass fibre surface to composite interface

DEFF Research Database (Denmark)

Petersen, Helga Nørgaard; Kusano, Yukihiro

significantly. The usage span wide, from furniture and car components to construction materials. Even though, the concept of composites is well known and widely applied, the fundamental principles of the interaction of the constituents, in the composites are still not fully understood. This thesis is a part...... of the sizing from the glass fibre surface to the interface in composites. Through soxhlet extraction with acetone it was possible to remove a part of the sizing from the glass fibres for analysis. By burning off the sizing at 565 ºC a higher mass loss was obtained than from the extraction, indicating...... increased after the removal of sizing by extraction but also when the sizing was removed by burning. This could partly be explained by the sizing being less dense than the glass fibres. For the burned glass fibres compactment of the glass structure also yields an increase in stiffness. The fibre strength...

Bioactive glass/hydroxyapatite composites: mechanical properties and biological evaluation.

Science.gov (United States)

Bellucci, Devis; Sola, Antonella; Anesi, Alexandre; Salvatori, Roberta; Chiarini, Luigi; Cannillo, Valeria

2015-06-01

Bioactive glass/hydroxyapatite composites for bone tissue repair and regeneration have been produced and discussed. The use of a recently developed glass, namely BG_Ca/Mix, with its low tendency to crystallize, allowed one to sinter the samples at a relatively low temperature thus avoiding several adverse effects usually reported in the literature, such as extensive crystallization of the glassy phase, hydroxyapatite (HA) decomposition and reaction between HA and glass. The mechanical properties of the composites with 80wt.% BG_Ca/Mix and 20wt.% HA are sensibly higher than those of Bioglass® 45S5 reference samples due to the presence of HA (mechanically stronger than the 45S5 glass) and to the thermal behaviour of the BG_Ca/Mix, which is able to favour the sintering process of the composites. Biocompatibility tests, performed with murine fibroblasts BALB/3T3 and osteocites MLO-Y4 throughout a multi-parametrical approach, allow one to look with optimism to the produced composites, since both the samples themselves and their extracts do not induce negative effects in cell viability and do not cause inhibition in cell growth. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparative study on the change in index of refraction in ion-exchange interdiffusion in alkali-silicate glasses containing calcium, strontium, barium and titanium oxides

International Nuclear Information System (INIS)

Livshits, V.Ya.; Marchuk, E.A.

1993-01-01

Different ability to ion exchange from the salts of lithium-sodium-silicate glass melt containing calcium (or strontium, or barium) and titanium oxides in addition has been shown. CaO, SrO and BaO have negative effect, but TiO 2 -positive one on the fullness of ion exchange of lithium-sodium and on the rate of interdiffusion in alkali-silicate glass. The value of change in index of refraction of glass with TiO 2 is twice higher than glass with calcium oxide (or strontium, or barium) as the fourth component

Electrical characterization of zirconia-niobium and zirconia-titanium composites

International Nuclear Information System (INIS)

Reis, S.T. dos.

1993-01-01

Zirconia-niobium and zirconia-titanium composites were made by powder mixing, cold pressing, and vacuum sintering at 1600 0 C. The metallic particles were added in the proportion of 0-50% by volume. Electrical resistivity measurements were performed by the two probes and the four probes d.c. method as a function of metallic particle concentration. Electrical resistivity of these composites decreased sharply in the region of 30-40 vol% Nb or Ti, in agreement with the percolation theory. Tests in an induction furnace were performed to check the self-heating response of these composites. (author). 33 refs, 40 figs, 11 tabs

Microwave-assisted ionothermal synthesis of nanostructured anatase titanium dioxide/activated carbon composite as electrode material for capacitive deionization

International Nuclear Information System (INIS)

Liu, Po-I; Chung, Li-Ching; Shao, Hsin; Liang, Teh-Ming; Horng, Ren-Yang; Ma, Chen-Chi M.; Chang, Min-Chao

2013-01-01

The nanostructured anatase titanium dioxide/activated carbon composite material for capacitive deionization electrode was prepared in a short time by a lower temperature two-step microwave-assisted ionothermal (sol–gel method in the presence of ionic liquid) synthesis method. This method includes a reaction and a crystallization step. In the crystallization step, the ionic liquid plays a hydrothermal analogy role in driving the surface anatase crystallization of amorphous titanium dioxide nanoparticles formed in the reaction step. The energy dispersive spectroscopic study of the composite indicates that the anatase titanium dioxide nanoparticles are evenly deposited in the matrix of activated carbon. The electrochemical property of the composite electrode was investigated. In comparison to the pristine activated carbon electrode, higher specific capacitance was observed for the nanostructured anatase titanium dioxide/activated carbon composite electrode, especially when the composite was prepared with a molar ratio of titanium tetraisopropoxide/H 2 O equal to 1:15. Its X-ray photoelectron spectroscopic result indicates that it has the highest amount of Ti-OH. The Ti-OH group can enhance the wetting ability and the specific capacitance of the composite electrode. The accompanying capacitive deionization result indicates that the decay of electrosorption capacity of this composite electrode is insignificant after five cycle tests. It means that the ion electrosorption–desorption becomes a reversible process

Durability testing with West Valley borosilicate glass composition- Phase II

International Nuclear Information System (INIS)

Macedo, P.B.; Finger, S.M.; Barkatt, A.A.; Pegg, I.L.; Feng, X.; Freeborn, W.P.

1988-06-01

This report presents the research performed by the Catholic University of America Vitreous State Laboratory (VSL) during FY 1987 in support of the West Valley Demonstration Project (WVDP) nuclear waste vitrification process. A principal objective of this work is the optimization of the glass composition be used for the vitrification of the liquid high-level waste generated at West Valley during nuclear fuel reprocessing. This report discusses (1) the experimental investigations to optimize the reference glass composition (the current leading candidates are WVCM-50 and ATM-10) for the WVDP vitrification process; (2) the systematic experimental investigation performed to determine the effects of compositional variations in WVCM-50 and WV-205 reference glasses on their viscosity and durability (including initial results of long-term leach tests of WVCM-50 under repository conditions); (3) the development of short-time and predictive leach tests; (4) the development of a process model for the West Valley vitrification process which predicts the range of glass compositions which may be encountered during normal operations and the effects of deviations in process control parameters; and (5) the development of product models for predicting the durability and viscosity of nuclear waste glasses

Development of sugar palm yarn/glass fibre reinforced unsaturated polyester hybrid composites

Science.gov (United States)

Nurazzi, N. Mohd; Khalina, A.; Sapuan, S. Mohd; Rahmah, M.

2018-04-01

This study investigates the effect of fibre hybridization for sugar palm yarn fibre with glass fibre reinforced with unsaturated polyester composites. In this work, unsaturated polyester resin are reinforced with fibre at a ratio of 70:30 wt% and 60:40 wt%. The hybrid composites were characterized in terms of physical (density and water absorption), mechanical (tensile, flexural and compression) and thermal properties through thermal gravimetry analysis (TGA). Density determination showed that density increased with higher wt% of glass fibre. The inherently higher density of glass fibre increased the density of hybrid composite. Resistance to water absorption is improved upon the incorporation of glass fibre and the hybrid composites were found to reach equilibrium absorption at days 4 and 5. As for mechanical performance, the highest tensile strength, tensile modulus, flexural strength, flexural modulus and compression strength were obtained from 40 wt% of fibres reinforcement with ratio of 50:50 wt% of sugar palm yarn fibre and glass fibre reinforced unsaturated polyester composites. The increase of glass fibre loading had a synergistic effect on the mechanical properties to the composites structure due to its superior strength and modulus. The thermal stability of hybrid composites was improved by the increase of onset temperature and the reduction of residues upon increase in temperature.

Composition-structure-property relation of oxide glasses

DEFF Research Database (Denmark)

Hermansen, Christian

also increases such properties. Yet, these rules are not strictly followed even for the simplest binary oxide glasses, such as alkali silicates, borates and phosphates. In this thesis it is argued that the missing link between composition and properties is the glass structure. Structural models...... are proposed based on topological selection rules and experimentally verified. The relation between structure and properties is evaluated using topological constraint theory, which in its essence is a theory that quantifies the two intuitions of the glass scientist. The end result is a quantitative model...

Investigation of mechanical properties of hemp/glass fiber reinforced nano clay hybrid composites

Science.gov (United States)

Unki, Hanamantappa Ningappa; Shivanand, H. K.; Vidyasagar, H. N.

2018-04-01

Over the last twenty to thirty years composite materials have been used in engineering field. Composite materials possess high strength, high strength to weight ratio due to these facts composite materials are becoming popular among researchers and scientists. The major proportion of engineering materials consists of composite materials. Composite materials are used in vast applications ranging from day-to-day household articles to highly sophisticated applications. In this paper an attempt is made to prepare three different composite materials using e-glass and Hemp. In this present investigation hybrid composite of Hemp, Glass fiber and Nano clay will be prepared by Hand-layup technique. The glass fiber used in this present investigation is E-glass fiber bi-directional: 90˚ orientation. The composite samples will be made in the form of a Laminates. The wt% of nanoclay added in the preparation of sample is 20 gm constant. The fabricated composite Laminate will be cut into corresponding profiles as per ASTM standards for Mechanical Testing. The effect of addition of Nano clay and variation of Hemp/glass fibers will be studied. In the present work, a new Hybrid composite is developed in which Hemp, E glass fibers is reinforced with epoxy resin and with Nano clay.

Tensile and Compressive Properties of Woven Kenaf/Glass Sandwich Hybrid Composites

Directory of Open Access Journals (Sweden)

Mohaiman J. Sharba

2016-01-01

Full Text Available Monotonic (tensile and compression properties of woven kenaf/glass reinforced unsaturated polyester sandwich hybrid composites have been experimentally investigated. Five types of composites laminates were fabricated using a combination of hand lay-up and cold press techniques, postcured for two hours at 80°C and left for 48 hours at room temperature. The hybrid composites contained fixed six layers of glass as a shell, three on each side, whereas the number of core kenaf layers was changed in three stages to get S1, S2, and S3 hybrid composites. Composites specimens with pure glass and kenaf were also fabricated for comparison. It was found that one kenaf layer replaced about 20% of total fiber weight fraction of the composite; this leads to reducing the density of final hybrid composite by 13%. Besides, in mechanical properties perspective, there are less than 1% reduction in compression strength and 40% in tensile strength when compared to pure glass composite. Generally, the results revealed that the best performance was observed in S1, which showed a good balance of all mechanical properties determined in this work.

Studies on fabrication of glass fiber reinforced composites using polymer blends

Science.gov (United States)

Patel, R. H.; Kachhia, P. H.; Patel, S. N.; Rathod, S. T.; Valand, J. K.

2018-05-01

Glass fiber reinforced PVC/NBR composites have been fabricated via hot compression moulding process. PVC is brittle in nature and thus lower thermal stability. Therefore, to improve the toughness of PVC, NBR was incorporated in certain proportions. As both are polar and thus they are compatible. To improve the strength property further, these blends were used to fabricate glass fiber reinforced composites. SEM micrograph shows good wettability of the blend with glass fibers resulting in proper bonding which increase the strength of the composites.

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)

Mechanical behaviour of degradable phosphate glass fibres and composites-a review.

Science.gov (United States)

Colquhoun, R; Tanner, K E

2015-12-23

Biodegradable materials are potentially an advantageous alternative to the traditional metallic fracture fixation devices used in the reconstruction of bone tissue defects. This is due to the occurrence of stress shielding in the surrounding bone tissue that arises from the absence of mechanical stimulus to the regenerating bone due to the mismatch between the elastic modulus of bone and the metal implant. However although degradable polymers may alleviate such issues, these inert materials possess insufficient mechanical properties to be considered as a suitable alternative to current metallic devices at sites of sufficient mechanical loading. Phosphate based glasses are an advantageous group of materials for tissue regenerative applications due to their ability to completely degrade in vivo at highly controllable rates based on the specific glass composition. Furthermore the release of the glass's constituent ions can evoke a therapeutic stimulus in vivo (i.e. osteoinduction) whilst also generating a bioactive response. The processing of these materials into fibres subsequently allows them to act as reinforcing agents in degradable polymers to simultaneously increase its mechanical properties and enhance its in vivo response. However despite the various review articles relating to the compositional influences of different phosphate glass systems, there has been limited work summarising the mechanical properties of different phosphate based glass fibres and their subsequent incorporation as a reinforcing agent in degradable composite materials. As a result, this review article examines the compositional influences behind the development of different phosphate based glass fibre compositions intended as composite reinforcing agents along with an analysis of different potential composite configurations. This includes variations in the fibre content, matrix material and fibre architecture as well as other novel composites designs.

Formulation of portland composite cement using waste glass as a supplementary cementitious material

Science.gov (United States)

Manullang, Ria Julyana; Samadhi, Tjokorde Walmiki; Purbasari, Aprilina

2017-09-01

Utilization of waste glass in cement is an attractive options because of its pozzolanic behaviour and the market of glass-composite cement is potentially available. The objective of this research is to evaluate the formulation of waste glass as supplementary cementitious material (SCM) by an extreme vertices mixture experiment, in which clinker, waste glass and gypsum proportions are chosen as experimental variables. The composite cements were synthesized by mixing all of powder materials in jar mill. The compressive strength of the composite cement mortars after being cured for 28 days ranges between 229 to 268 kg/cm2. Composite cement mortars exhibit lower compressive strength than ordinary Portland cement (OPC) mortars but is still capable of meeting the SNI 15-7064-2004 standards. The highest compressive strength is obtained by shifting the cement blend composition to the direction of increasing clinker and gypsum proportions as well as reducing glass proportion. The lower compressive strength of composite cement is caused by expansion due to ettringite and ASR gel. Based on the experimental result, the composite cement containing 80% clinker, 15% glass and 5% gypsum has the highest compressive strength. As such, the preliminary technical feasibility of reuse of waste glass as SCM has been confirmed.

Measurement of the body composition of living gray seals by hydrogen isotope dilution

International Nuclear Information System (INIS)

Reilly, J.J.; Fedak, M.A.

1990-01-01

The body composition of living gray seals (Halichoerus grypus) can be accurately predicted from a two-step model that involves measurement of total body water (TBW) by 2 H or 3 H dilution and application of predictive relationships between body components and TBW that were derived empirically by slaughter chemical analysis. TBW was overestimated by both 2 HHO and 3 HHO dilution; mean overestimates were 2.8 +/- 0.9% (SE) with 2H and 4.0 +/- 0.6% with 3 H. The relationships for prediction of total body fat (TBF), protein (TBP), gross energy (TBGE), and ash (TBA) were as follows: %TBF = 105.1 - 1.47 (%TBW); %TBP = 0.42 (%TBW) - 4.75; TBGE (MJ) = 40.8 (mass in kg) - 48.5 (TBW in kg) - 0.4; and TBA (kg) = 0.1 - 0.008 (mass in kg) + 0.05 (TBW in kg). These relationships are applicable to gray seals of both sexes over a wide range of age and body conditions, and they predict the body composition of gray seals more accurately than the predictive equations derived from ringed seals (Pusa hispida) and from the equation of Pace and Rathbun, which has been reported to be generally applicable to mammals

Circumferential shaft seal

Science.gov (United States)

Ludwig, L. P. (Inventor)

1981-01-01

A circumferential shaft seal comprising two sealing rings held to a rotating shaft by means of a surrounding elastomeric band is disclosed. The rings are segmented and are of a rigid sealing material such as carbon or a polyimide and graphite fiber composite.

Strength of bond with Comspan Opaque to three silicoated alloys and titanium.

Science.gov (United States)

Hansson, O

1990-06-01

In Sweden high-gold alloys or cobalt-chromium alloys are used for resin-bonded prostheses. The bond strength between a resin cement and different sandblasted or silicoated metals were measured before and after thermocycling; in connection with this some rapid thermocycling methods were studied. The effect of different storage times and different protection coatings on bond strength were tested. Finally, the influence of rubbing and contamination with saliva on bond strength were investigated. Silicoating increased the bond strength significantly. The highest bond strengths were these of silicoated Wirobond and titanium, unsusceptible to thermal stress; the bond strengths of the sandblasted metals were the weakest, and sensitive to thermocycling as well. The influence on bond strength for silicoated gold alloys, protected with an unpolymerized composite resin coating, stored in sealed plastic bags up to 7 days, was negligible. Rubbing and contamination with saliva did not influence bond strength. Preferably, silicoated Wirobond and titanium should be used for resin-bonded prostheses, but gold alloys may still be adequate for clinical use. The experimental method described for storing, sealing, and cleaning the silicoated metal surfaces in this article can be recommended for laboratory and clinical use.

Estimation of grey seal (Halichoerus grypus diet composition in the Baltic Sea

Directory of Open Access Journals (Sweden)

Karl Lundström

2007-01-01

Full Text Available We examined the digestive tract contents from 145 grey seals (Halichoerus grypus collected between 2001 and 2004 in the Baltic Sea. We compensated for biases introduced by erosion of otoliths, both by using additional hard-part structures other than otoliths, and species-specific size and numerical correction factors. In the absence of numerical correction factors based on feeding experiments for some species, we used correction factors based on a relationship between otolith recoveryrate and otolith width. A total of 24 prey taxa were identified but only a few species contributed substantially to the diet. The estimated diet composition was, independently of the prey number estimation method and diet composition estimation model used, dominated by herring (Clupea harengus, both by numbers and biomass. In addition to herring, common whitefish (Coregonus lavaretus and sprat (Sprattus sprattus were important prey, but cyprinids (Cyprinidae, eelpout (Zoarces viviparus, flounder (Platichtys flesus and salmon (Salmo salar also contributed significantly. Our results indicated dietary differences between grey seals of different age as well as between seals from the northern (Gulf of Bothnia and the southern (Baltic Proper Baltic Sea.

Methods of vitrifying waste with low melting high lithia glass compositions

Science.gov (United States)

Jantzen, Carol M.; Pickett, John B.; Cicero-Herman, Connie A.; Marra, James C.

2001-01-01

The invention relates to methods of vitrifying waste and for lowering the melting point of glass forming systems by including lithia formers in the glass forming composition in significant amounts, typically from about 0.16 wt % to about 11 wt %, based on the total glass forming oxides. The lithia is typically included as a replacement for alkali oxide glass formers that would normally be present in a particular glass forming system. Replacement can occur on a mole percent or weight percent basis, and typically results in a composition wherein lithia forms about 10 wt % to about 100 wt % of the alkali oxide glass formers present in the composition. The present invention also relates to the high lithia glass compositions formed by these methods. The invention is useful for stabilization of numerous types of waste materials, including aqueous waste streams, sludge solids, mixtures of aqueous supernate and sludge solids, combinations of spent filter aids from waste water treatment and waste sludges, supernate alone, incinerator ash, incinerator offgas blowdown, or combinations thereof, geological mine tailings and sludges, asbestos, inorganic filter media, cement waste forms in need of remediation, spent or partially spent ion exchange resins or zeolites, contaminated soils, lead paint, etc. The decrease in melting point achieved by the present invention desirably prevents volatilization of hazardous or radioactive species during vitrification.

Composition and redox control of waste glasses: Recommendation for process control limit

International Nuclear Information System (INIS)

Jantzen, C.M.; Plodinec, M.J.

1986-01-01

An electrochemical series of redox couples, originally developed for Savannah River Laboratory glass frit 131 (SRL-131) as a reference composition, has been extended to two other alkali borosilicate compositions that are candidate glasses for nuclear waste immobilization. Since no dramatic differences were ascertained in the redox chemistry of selected multivalent elements in SRL-131 versus that in Savannah River Laboratory glass frit 165 (SRL-165) and in West Valley glass number-sign 205 (WV-205), the comprehensive electrochemical series can readily be applied to a range of nuclear waste glass compositions. In order to alleviate potential problems with foaming and precipitation of insolubles during the processing of the nuclear waste in these glass melts, the [Fe 2+ ]/[Fe 3+ ] ratio of the melt should be between 0.1 and 0.5. 27 refs., 4 figs., 2 tabs

Structure, composition and morphology of bioactive titanate layer on porous titanium surfaces

Science.gov (United States)

Li, Jinshan; Wang, Xiaohua; Hu, Rui; Kou, Hongchao

2014-07-01

A bioactive coating was produced on pore surfaces of porous titanium samples by an amendatory alkali-heat treatment method. Porous titanium was prepared by powder metallurgy and its porosity and average size were 45% and 135 μm, respectively. Coating morphology, coating structure and phase constituents were examined by SEM, XPS and XRD. It was found that a micro-network structure with sizes of cells, and redundant Ca ion was detected in the titanate layer. The concentration distribution of Ti, O, Ca and Na in the coating showed a compositional gradient from the intermediate layer toward the outer surface. These compositional gradients indicate that the coating bonded to Ti substrate without a distinct interface. After immersion into the SBF solution for 3 days, a bone-like carbonate-hydroxylapatite showing a good biocompatibility was detected on the coating surface. And the redundant Ca advanced the bioactivity of the coating. Thus, the present modification is expected to allow the use of the bioactive porous titanium as artificial bones even under load-bearing conditions.

Structural characterization and anti-cancerous potential of gallium bioactive glass/hydrogel composites.

Science.gov (United States)

Keenan, T J; Placek, L M; Coughlan, A; Bowers, G M; Hall, M M; Wren, A W

2016-11-20

A bioactive glass series (0.42SiO2-0.10Na2O-0.08CaO-(0.40-X)ZnO-(X)Ga2O3) was incorporated into carboxymethyl cellulose (CMC)/dextran (Dex) hydrogels in three different amounts (0.05, 0.10, and 0.25m(2)), and the resulting composites were characterized using transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and (13)C Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance (CP MAS-NMR). Composite extracts were also evaluated in vitro against MG-63 osteosarcoma cells. TEM confirmed glass distribution throughout the composites, although some particle agglomeration was observed. DSC revealed that glass composition and content did have small effects on both Tg and Tm. MAS-NMR revealed that both CMC and Dex were successfully functionalized, that cross-linking occurred, and that glass addition did slightly alter bonding environments. Cell viability analysis suggested that extracts of the glass and composites with the largest Ga-content significantly decreased MG-63 osteosarcoma viability after 30days. This study successfully characterized this composite series, and demonstrated their potential for anti-cancerous applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Durability-Based Design Criteria for a Chopped-Glass-Fiber Automotive Structural Composite; TOPICAL

International Nuclear Information System (INIS)

Battiste, R.L.; Corum, J.M.; Ren, W.; Ruggles, M.B.

1999-01-01

This report provides recommended durability-based design criteria for a chopped-glass-fiber reinforced polymeric composite for automotive structural applications. The criteria closely follow the framework of an earlier criteria document for a continuous-strand-mat (CSM) glass-fiber reference composite. Together these design criteria demonstrate a framework that can be adapted for future random-glass-fiber composites for automotive structural applications

A Study On The Metal Carbide Composite Diffusion Bonding For Mechanical Seal

Directory of Open Access Journals (Sweden)

Kim D.-K.

2015-06-01

Full Text Available Mechanical Seal use highly efficient alternative water having a great quantity of an aqueous solution and has an advantage no corrosion brine. Metal Carbide composites have been investigated as potential materials for high temperature structural applications and for application in the processing industry. The existing Mechanical seal material is a highly expensive carbide alloy, and it is difficult to take a price advantage. Therefore the study of replacing body area with inexpensive steel material excluding O-ring and contact area which demands high characteristics is needed.

Improvement of the piezoelectric properties of glass fiber-reinforced epoxy composites by poling treatment

International Nuclear Information System (INIS)

Oh, S M; Hwang, H Y

2013-01-01

Recently, a new non-destructive method has been proposed for damage monitoring of glass fiber-reinforced polymer composite materials using the piezoelectric characteristics of a polymeric matrix. Several studies of the piezoelectric properties of unidirectional glass fiber epoxy composites and damage monitoring of double-cantilever beams have supported the claim that the piezoelectric method is feasible and powerful enough to monitor the damage of glass fiber epoxy composites. Generally, conventional piezoelectric materials have higher piezoelectric characteristics through poling treatment. In this work, we investigated the change of the piezoelectric properties of glass fiber-reinforced epoxy composites before and after poling treatment. The piezoelectric constants (d 33 ) of glass fiber-reinforced epoxy composites increased by more than 400%. Also, x-ray diffraction tests revealed that poling treatment changed the degree of crystallinity of the epoxy matrix, and this led to the improvement of the piezoelectric characteristics of glass fiber-reinforced epoxy composites. (paper)

Neural network analysis of nuclear waste glass composition vs durability

International Nuclear Information System (INIS)

Seibel, C.K.

1994-01-01

The relationship between the chemical composition of oxide glasses and their physical properties is poorly understood, but it is becoming more important as vitrification (transformation into glass) of high-level nuclear waste becomes the favored method for long-term storage. The vitrified waste will be stored deep in geologic repositories where it must remain intact for at least 10,000 years. A strong resistance to groundwater exposure; i.c. a slow rate of glass dissolution, is of great importance. This project deals specifically with glass samples developed and tested for the nuclear fuel reprocessing facility near West Valley, New York. This facility needs to dispose of approximately 2.2 million liters of high-level radioactive liquid waste currently stored in stainless steel tanks. A self-organizing, artificial neural network was used to analyze the trends in the glass dissolution data for the effects of composition and the resulting durability of borosilicate glasses in an aqueous environment. This durability data can be used to systematically optimize the properties of the complex nuclear glasses and slow the dissolution rate of radionuclides into the environment

Segmental stability in orthognathic surgery: hydroxyapatite/Poly-l-lactide osteoconductive composite versus titanium miniplate osteosyntheses.

Science.gov (United States)

Landes, Constantin A; Ballon, Alexander; Tran, Andreas; Ghanaati, Shahram; Sader, Robert

2014-09-01

Hydroxyapatite was included into F-u-HA/PLLA (unsintered hydroxyapatite - Poly l-lactide) composite osteosynthesis material for its documented osteoconductive capacity. This study investigates segmental retention capacities and outcome stability using F-u-HA/PLLA composite osteosyntheses in orthognathic surgery. Of fifty patients in total, 25 patients were osteofixated with F-u-HA/PLLA osteoconductive bioabsorbable osteosyntheses and compared to a group of 25 patients treated with titanium miniplates. The F-u-HA/PLLA group included 14 maxillary advancements, 4 setbacks, 13 impactions, 5 elongations at A-point; the titanium group included 20 maxillary advancements, 2 setbacks, 11 impactions and 11 elongations. In the mandible the F-u-HA/PLLA group included 13 advancements at B-point, 11 setbacks, 16 clockwise rotations and 8 counterclockwise rotations at the Gonial angle (Ar-Go-Gn); the titanium group included 9 mandibular advancements, 5 setbacks, 8 clockwise rotations and 6 counterclockwise rotations at Ar-Go-Gn. Segmental stability and relapse were assessed comparing preoperative, postoperative and follow-up roentgen cephalometrics at 22 ± 11 months on average in F-u-HA/PLLA cases, 24 ± 22 months on average in the titanium group. All absolute operative movements were nonsignificant in the F-u-HA/PLLA cases compared to the titanium osteosynthesis cases. Relapses were nonsignificant but there was greater vertical relapse in maxillary impactions with titanium osteosyntheses. Throughout this study, F-u-HA/PLLA composite osteosyntheses appeared as stable as titanium miniplates. It can therefore be concluded, although from a limited number of patients, that the investigated osteoconductive osteosynthesis can be used in a similar way to titanium miniplates in orthognathic surgery. Compared to earlier studies using other bioabsorbable polymers in the literature, F-u-HA/PLLA proved to be more stable in segmental retention. Copyright © 2014 European Association for

Tensile properties of in situ synthesized titanium matrix composites reinforced by TiB and Nd2O3 at elevated temperature

International Nuclear Information System (INIS)

Geng Ke; Lu Weijie; Zhang Di; Sakata, Taokao; Mori, Hirotaro

2003-01-01

Titanium matrix composites reinforced with TiB and Nd 2 O 3 were prepared by a non-consumable arc-melting technology. X-ray diffraction (XRD) was used to identify the phases in the composites. Microstructures of the composites were observed by means of optical microscope (OM). There are three phases: TiB, Nd 2 O 3 and titanium matrix. TiB grows in needle shape, whereas Nd 2 O 3 grows in lath shape. Tensile properties of the composites were tested at 773, 823 and 873 K. Both the fracture surfaces and longitudinal sections of the fractured tensile specimens were comprehensively examined by scanning electron microscope (SEM). The fracture mode and fracture process at different temperatures were analyzed and explained. It shows that the tensile strength of the composites has a significant improvement at elevated temperatures compared to titanium matrix. The ductility of the composites improves with the content of neodymium and the test temperatures. The titanium composite exhibits different fracture modes at different test temperatures

Plasmonic Glasses and Films Based on Alternative Inexpensive Materials for Blocking Infrared Radiation.

Science.gov (United States)

V Besteiro, Lucas; Kong, Xiang-Tian; Wang, Zhiming; Rosei, Federico; Govorov, Alexander O

2018-04-16

The need for energy-saving materials is pressing. This Letter reports on the design of energy-saving glasses and films based on plasmonic nanocrystals that efficiently block infrared radiation. Designing such plasmonic composite glasses is nontrivial and requires taking full advantage of both material and geometrical properties of the nanoparticles. We compute the performance of solar plasmonic glasses incorporating a transparent matrix and specially shaped nanocrystals. This performance depends on the shape and material of such nanocrystals. Glasses designed with plasmonic nanoshells are shown to exhibit overall better performances as compared to nanorods and nanocups. Simultaneously, scalable synthesis of plasmonic nanoshells and nanocups is technologically feasible using gas-phase fabrication methods. The computational simulations were performed for noble metals (gold and silver) as well as for alternative plasmonic materials (aluminum, copper, and titanium nitride). Inexpensive plasmonic materials (silver, copper, aluminum, and titanium nitride) show an overall good performance in terms of the commonly used figures of merit of industrial glass windows. Together with numerical data for specific materials, this study includes a set of general rules for designing efficient plasmonic IR-blocking media. The plasmonic glasses proposed herein are good candidates for the creation of cheap optical media, to be used in energy-saving windows in warm climates' housing or temperature-sensitive infrastructure.

Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite

Directory of Open Access Journals (Sweden)

Richard C. Petersen

2014-12-01

Full Text Available The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo

Modification of the Surface Topography and Composition of Ultrafine and Coarse Grained Titanium by Chemical Etching.

Science.gov (United States)

Nazarov, Denis V; Zemtsova, Elena G; Solokhin, Alexandr Yu; Valiev, Ruslan Z; Smirnov, Vladimir M

2017-01-13

In this study, we present the detailed investigation of the influence of the etching medium (acidic or basic Piranha solutions) and the etching time on the morphology and surface relief of ultrafine grained (UFG) and coarse grained (CG) titanium. The surface relief and morphology have been studied by means of scanning electron microscopy (SEM), atomic force microscopy (AFM), and the spectral ellipsometry. The composition of the samples has been determined by X-ray fluorescence analysis (XRF) and X-ray Photoelectron Spectroscopy (XPS). Significant difference in the etching behavior of UFG and CG titanium has been found. UFG titanium exhibits higher etching activity independently of the etching medium. Formed structures possess higher homogeneity. The variation of the etching medium and time leads to micro-, nano-, or hierarchical micro/nanostructures on the surface. Significant difference has been found between surface composition for UFG titanium etched in basic and acidic Piranha solution. Based on the experimental data, the possible reasons and mechanisms are considered for the formation of nano- and microstructures. The prospects of etched UFG titanium as the material for implants are discussed.

Predicting glass-forming compositions in the Al-La and Al-La-Ni systems

International Nuclear Information System (INIS)

Gargarella, P.; de Oliveira, M.F.; Kiminami, C.S.; Pauly, S.; Kuehn, U.; Bolfarini, C.; Botta, W.J.; Eckert, J.

2011-01-01

Research highlights: → The glass-forming ability of the Al-La and Al-La-Ni systems was studied using the λ* and the λ.Δe criteria. → Both criteria predicted with just 1% at. of error the best glass-former verified so far in the Al-La system. → Four new glass-former compositions could be predicted in the Al-La-Ni system using the λ.Δe criterion. → The best glass-former reported so far in the Al-La-Ni system was found. - Abstract: In this work, a criterion considering the topological instability (λ) and the differences in the electronegativity of the constituent elements (Δe) was applied to the Al-La and Al-Ni-La systems in order to predict the best glass-forming compositions. The results were compared with literature data and with our own experimental data for the Al-La-Ni system. The alloy described in the literature as the best glass former in the Al-La system is located near the point with local maximum for the λ.Δe criterion. A good agreement was found between the predictions of the λ.Δe criterion and literature data in the Al-La-Ni system, with the region of the best glass-forming ability (GFA) and largest supercooled liquid region (ΔT x ) coinciding with the best compositional region for amorphization indicated by the λ.Δe criterion. Four new glassy compositions were found in the Al-La-Ni system, with the best predicted composition presenting the best glass-forming ability observed so far for this system. Although the λ.Δe criterion needs further refinements for completely describe the glass-forming ability in the Al-La and Al-La-Ni systems, the results demonstrated that this criterion is a good tool to predict new glass-forming compositions.

Optimization of glass composition for the vitrification of nuclear waste at the Savannah River Plant

International Nuclear Information System (INIS)

Soper, P.D.; Roberts, G.J.; Lightner, L.F.; Walker, D.D.; Plodinec, M.J.

1982-01-01

Waste glasses of different compositions were compared in terms of leachability, viscosity, liquidus temperature, and coefficient of expansion. The compositions of the glasses were determined by statistical optimization. Waste glass of the optimized composition is more durable than the current reference composition but can still be processed at low temperature

The influence of stiffeners on axial crushing of glass-fabric-reinforced epoxy composite shells

Directory of Open Access Journals (Sweden)

A. Vasanthanathan

2017-01-01

Full Text Available A generic static and impact experimental procedure has been developed in this work aimed at improving the stability of glass fabric reinforced epoxy shell structures by bonding with axial stiffeners. Crashworthy structures fabricated from composite laminate with stiffeners would offer energy absorption superior to metallic structures under compressive loading situations. An experimental material characterisation of the glass fabric reinforced epoxy composite under uni-axial tension has been carried out in this study. This work provides a numerical simulation procedure to describe the static and dynamic response of unstiffened glass fabric reinforced epoxy composite shell (without stiffeners and stiffened glass fabric reinforced epoxy composite shell (with axial stiffeners under static and impact loading using the Finite Element Method. The finite element calculation for the present study was made with ANSYS®-LS-DYNA® software. Based upon the experimental and numerical investigations, it has been asserted that glass fabric reinforced epoxy shells stiffened with GFRP stiffeners are better than unstiffened glass fabric reinforced epoxy shell and glass fabric reinforced epoxy shell stiffened with aluminium stiffeners. The failure surfaces of the glass fabric reinforced epoxy composite shell structures tested under impact were examined by SEM.

Calcium phosphate glass-ceramics for bioactive coating on a β-titanium alloy

International Nuclear Information System (INIS)

Kasuga, T.; Nogami, M.; Niinomi, M.

2003-01-01

The formation of a porous coating is the decisive feature for the bio-compatibility of silica-free calcium phosphate glass ceramics on alloy surfaces like the β-Ti structured Ti-29Nb-13Ta-4.6Zr used in this work. The ceramic composition is highly important: 50CaO-40P 2 O 5 -7Na 2 O-3TiO 2 glass powder produces a pore-free coating unable to bind hydroxyapatite, whereas 60CaO-30P 2 O 5 -7Na 2 O-3TiO 2 glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Composition dependence of the optical and structural properties of Eu-doped oxyfluoride glasses

DEFF Research Database (Denmark)

Zhu, C.F.; Wu, D.Q.; Zhang, Y.F.

2015-01-01

Europium doped oxyfluoride glasses were prepared by the melt quenching method for the light emitting diodes applications. The optical and structural properties of these glasses were studied by means of photoluminescence spectra, Commission Internationale de L'Eclairage chromaticity coordinates, X...... compositions. Finally, we propose a mechanism to explain how the glass structure affects the reduction of Eu ions as well as optical properties of the glasses.......Europium doped oxyfluoride glasses were prepared by the melt quenching method for the light emitting diodes applications. The optical and structural properties of these glasses were studied by means of photoluminescence spectra, Commission Internationale de L'Eclairage chromaticity coordinates, X...... on the base glass compositions. For certain base glass compositions, CaF2 crystals can form during the melt cooling process, and thereby enhance the conversion from Eu3+ to Eu2+. The formation of CaF2 crystals can be suppressed by adding CaO, Al2O3 and B2O3, but enhanced by adding Na2O and K2O in glass...

Glass composite waste forms for iodine confined in bismuth-embedded SBA-15

Energy Technology Data Exchange (ETDEWEB)

Yang, Jae Hwan [Nuclear Fuel Cycle Process Development Division, Korea Atomic Energy Research Institute, 989-111 Daeduk-daero, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of); Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Park, Hwan Seo; Ahn, Do-Hee [Nuclear Fuel Cycle Process Development Division, Korea Atomic Energy Research Institute, 989-111 Daeduk-daero, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of); Yim, Man-Sung, E-mail: msyim@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of)

2016-11-15

The aim of this study was to stabilize bismuth-embedded SBA-15 that captured iodine gas by fabrication of monolithic waste forms. The iodine containing waste was mixed with Bi{sub 2}O{sub 3} (a stabilizing additive) and low-temperature sintering glass followed by pelletizing and the sintering process to produce glass composite materials. Iodine volatility during the sintering process was significantly affected by the ratio of Bi{sub 2}O{sub 3} and the glass composition. It was confirmed that BiI{sub 3}, the main iodine phase within bismuth-embedded SBA-15, was effectively transformed to the mixed phases of Bi{sub 5}O{sub 7}I and BiOI. The initial leaching rates of iodine from the glass composite waste forms ranged 10{sup −3}–10{sup −2} g/m{sup 2} day, showing the stability of the iodine phases encapsulated by the glassy networks. It was also observed that common groundwater anions (e.g., chloride, carbonate, sulfite, and fluoride) elevated the iodine leaching rate by anion exchange reactions. The present results suggest that the glass composite waste form of bismuth-embedded SBA-15 could be a candidate material for stable storage of {sup 129}I. - Highlights: • Glass composite waste forms were developed to stabilize iodine confined in Bi-embedded SBA-15. • BiI{sub 3} within Bi-embedded SBA-15 was transformed to BiOI and Bi{sub 5}O{sub 7}I during sintering process. • Iodine volatility was significantly affected by glass composition and Bi{sub 2}O{sub 3} additive. • Iodine leaching rates were 10{sup −3}–10{sup −2} g/m{sup 2} day due to the stable iodine phases encapsulated by glassy networks. • Glass composite waste form of Bi-embedded SBA-15 is expected to be a candidate material for stable storage of {sup 129}I.

Dependence of Hardness of Silicate Glasses on Composition and Thermal History

DEFF Research Database (Denmark)

Jensen, Martin; Smedskjær, Morten Mattrup; Yue, Yuanzheng

composition on hardness of silicate glasses. E-glasses of different compositions are subjected to various degrees of annealing to obtain various fictive temperatures in the glasses. It is found that hardness decreases with the fictive temperature. Addition of Na2O to a SiO2-Al2O3-Na2O glass system causes......The prediction of hardness is possible for crystalline materials, but so far not possible for glasses. In this work, several important factors that should be used for predicting the hardness of glasses are discussed. To do so, we have studied the influences of thermal history and chemical...... a decrease in hardness. However, hardness cannot solely be determined from the degree of polymerisation of the glass network. It is also determined by the effect of ionic radius on hardness. However, this effect has opposite trend for alkali and alkaline earth ions. The hardness increases with ionic radius...

Influence of nuclear glasses composition on their liability to deterioration; Influence de la composition des verres nucleaires sur leur alterabilite

Energy Technology Data Exchange (ETDEWEB)

Tovena, I

1995-09-29

This contributes to the study of the nuclear glasses composition influence on their liability to deterioration. The methodology of the experimental research used has lead to define between the thirty oxides which form the reference glass light water, six oxides of interest. For each of these oxides, a composition variation area has been defined. A matrix of twenty glass compositions has then been defined. The preparation of materials of these compositions has sometimes lead to materials weakly heterogeneous which have been characterized before deterioration. This study has been completed by those of three glasses in a composition variation area narrower of the light water nuclear glass : the R7T7 and two glasses at limits having respectively an initial dissolution velocity at 100 degrees Celsius theoretically maximum and minimum. Some deterioration parameters in pure water have been experimentally measured on the twenty three glasses : 1) an initial dissolution velocity at 100 degrees (Vo{sub 1}00) Celsius and another one at 90 degrees Celsius (Vo{sub 9}0) 2) a dissolution velocity in conditions near the saturation at 90 degrees Celsius 3) an apparent solubility of glass based on the ortho silicic acid activity 4) the evolution of the dissolution kinetics at 90 degrees Celsius in sub-saturated medium towards saturated medium 5) the alteration films nature developed at the glasses surface during these last alteration tests. Some thermodynamic and structural models have been studied in order to predict Vo{sub 9}0 and Vo{sub 1}00. The dissolution kinetic law developed from reference glass dissolution results has been studied with the calculation code LIXIVER. It has not been able to be used for most of the glasses compositions studied. As a consequence, the glasses dissolution control by a surface reaction which are itself controlled by the only dissolved silica is an hypothesis which is not verified for the greater part of the glasses. (O.L.). refs., figs., tabs.

Phase 2B experimental design for the INEEL glass composition variation study

International Nuclear Information System (INIS)

Peeler, D.

2000-01-01

The U.S. Department of Energy's (DOE's) Offices of Science and Technology (through the Tanks Focus Area [TFA]) and Waste Management are sponsoring a partnership among Idaho National Engineering and Environmental Laboratory (INEEL), Pacific Northwest National Laboratory (PNNL), and the Savannah River Technology Center (SRTC) for a collaborative glass composition variation study (CVS). The purpose of the CVS is to investigate property - composition relationships within a glass-composition region compatible with the expected range of Idaho Nuclear Technology and Engineering Center (INTEC) high-activity wastes (HAWs). The CVS has been conducted in phases to allow INEEL, PNNL, and SRTC researchers to adjust the glass composition region of interest as flowsheet options are refined and/or waste-stream compositions become more defined

Composition dependence of the optical and structural properties of Eu-doped oxyfluoride glasses

International Nuclear Information System (INIS)

Zhu, Chaofeng; Wu, Dongqun; Zhang, Yanfei; Zhang, Meimei; Yue, Yuanzheng

2015-01-01

Highlights: • Eu doped oxyfluoride glasses for LED applications are studied. • Conversion of Eu 3+ to Eu 2+ is realized in the glasses prepared in air atmosphere. • CaF 2 crystals formed during melt cooling enhance the conversion of Eu 3+ to Eu 2+ . • Content of CaF 2 crystals can be controlled by adjusting base glass compositions. - Abstract: Europium doped oxyfluoride glasses were prepared by the melt quenching method for the light emitting diodes applications. The optical and structural properties of these glasses were studied by means of photoluminescence spectra, Commission Internationale de L’Eclairage chromaticity coordinates, X-ray diffraction, and Fourier transform infrared spectra. We find that the spontaneous reduction of Eu 3+ to Eu 2+ is realized by Eu 3+ ions occupying the sites of Ca 2+ in the glasses prepared in air atmosphere. The Eu 3+ to Eu 2+ conversion efficiency, optical performances and structure of the glasses strongly depend on the base glass compositions. For certain base glass compositions, CaF 2 crystals can form during the melt cooling process, and thereby enhance the conversion from Eu 3+ to Eu 2+ . The formation of CaF 2 crystals can be suppressed by adding CaO, Al 2 O 3 and B 2 O 3 , but enhanced by adding Na 2 O and K 2 O in glass compositions. Finally, we propose a mechanism to explain how the glass structure affects the reduction of Eu ions as well as optical properties of the glasses

Structure and Degradation Behaviour of Calcium Phosphate Glasses

International Nuclear Information System (INIS)

Silva, A M B; Correia, R N; Fernandes, M H V; Oliveira, J M M

2011-01-01

Some studies have shown a relationship between glass structure and in vitro mineralization, generally associated with the rate of glass degradation, nature of released ions and subsequent Ca-P precipitation on glass surfaces when immersed in a Simulated Body Fluid (SBF). The knowledge of the ionic species distribution in glasses and of the involved bond strengths can be used to assess the in vitro behaviour of a glass. The role of ions such as silicon or titanium is of major importance for the development of new compositions and also for the control of glass degradation behaviour. A comparative study with two calcium phosphate glasses series was performed: Both glasses series - one with Si and another with Ti - include P 2 O 5 and alkaline earth ions in their compositions. Surface reactivity of glasses from the SiO 2 -containing system have been studied in SBF showing the precipitation of a Ca-P surface layer that increases with increasing MgO/CaO ratio. In glasses from the TiO 2 -containing series it is shown that the increase of TiO 2 contributes for the stabilization of the glass network thus allowing the control of their degradation rate when immersed in SBF. The relationship between structural features of these calcium-phosphate glasses and their degradation behaviour in SBF is discussed in terms of the structural role of Si and Ti ions. It is concluded that glasses with less interconnected species favour the Ca-P surface precipitation. The understanding of this relationship in synthetic physiological fluids is expected to allow the tailoring of glass degradation rates in complex biological systems.

Electrophoretic deposition of calcium silicate-reduced graphene oxide composites on titanium substrate

DEFF Research Database (Denmark)

Mehrali, Mehdi; Akhiani, Amir Reza; Talebian, Sepehr

2016-01-01

Calcium silicate (CS)/graphene coatings have been used to improve the biological and mechanical fixation of metallic prosthesis. Among the extraordinary features of graphene is its very high mechanical strength, which makes it an attractive nanoreinforcement material for composites. Calcium...... silicate-reduced graphene oxide (CS-rGO) composites were synthesized, using an in situ hydrothermal method. CS nanowires were uniformly decorated on the rGO, with an appropriate interfacial bonding. The CS-rGO composites behaved like hybrid composites when deposited on a titanium substrate by cathodic...

Fibre-matrix bond strength studies of glass, ceramic, and metal matrix composites

Science.gov (United States)

Grande, D. H.; Mandell, J. F.; Hong, K. C. C.

1988-01-01

An indentation test technique for compressively loading the ends of individual fibers to produce debonding has been applied to metal, glass, and glass-ceramic matrix composites; bond strength values at debond initiation are calculated using a finite-element model. Results are correlated with composite longitudinal and interlaminar shear behavior for carbon and Nicalon fiber-reinforced glasses and glass-ceramics including the effects of matrix modifications, processing conditions, and high-temperature oxidation embrittlement. The data indicate that significant bonding to improve off-axis and shear properties can be tolerated before the longitudinal behavior becomes brittle. Residual stress and other mechanical bonding effects are important, but improved analyses and multiaxial interfacial failure criteria are needed to adequately interpret bond strength data in terms of composite performance.

Elaboration of new ceramic composites containing glass fibre production wastes

International Nuclear Information System (INIS)

Rozenstrauha, I.; Sosins, G.; Krage, L.; Sedmale, G.; Vaiciukyniene, D.

2013-01-01

Two main by-products or waste from the production of glass fibre are following: sewage sludge containing montmorillonite clay as sorbent material and ca 50 % of organic matter as well as waste glass from aluminium borosilicate glass fibre with relatively high softening temperature (> 600 degree centigrade). In order to elaborate different new ceramic products (porous or dense composites) the mentioned by-products and illitic clay from two different layers of Apriki deposit (Latvia) with illite content in clay fraction up to 80-90 % was used as a matrix. The raw materials were investigated by differential-thermal (DTA) and XRD analysis. Ternary compositions were prepared from mixtures of 15 - 35 wt % of sludge, 20 wt % of waste glass and 45 - 65 wt % of clay and the pressed green bodies were thermally treated in sintering temperature range from 1080 to 1120 degree centigrade in different treatment conditions. Materials produced in temperature range 1090 - 1100 degree centigrade with the most optimal properties - porosity 38 - 52 %, water absorption 39 -47 % and bulk density 1.35 - 1.67 g/cm 3 were selected for production of porous ceramics and materials showing porosity 0.35 - 1.1 %, water absorption 0.7 - 2.6 % and bulk density 2.1 - 2.3 g/cm 3 - for dense ceramic composites. Obtained results indicated that incorporation up to 25 wt % of sewage sludge is beneficial for production of both ceramic products and glass-ceramic composites according to the technological properties. Structural analysis of elaborated composite materials was performed by scanning electron microscopy(SEM). By X-ray diffraction analysis (XRD) the quartz, diopside and anorthite crystalline phases were detected. (Author)

Bioactive glass/ZrO2 composites for orthopaedic applications

International Nuclear Information System (INIS)

Bellucci, D; Sola, A; Cannillo, V

2014-01-01

Binary biocomposites were realized by combining yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) with a bioactive glass matrix. Few works are available regarding composites containing zirconia and a relatively high content of glass because the resulting samples are usually biocompatible but not bioactive after thermal treatment. In the present research, the promising properties of the new BG C a–K glass, with its low tendency to crystallize and high apatite-forming ability, allowed us to sinter the composites at a relatively low temperature with excellent effects in terms of bioactivity. In addition, it was possible to benefit from the good mechanical behaviour of Y-TZP, thus obtaining samples with microhardness values that were among the highest reported in the literature. After a detailed analysis regarding the thermal behaviour of the composite powders, the sintered bodies were fully characterized by means of x-ray diffraction, SEM equipped with EDS, density measurements, volumetric shrinkage determination, mechanical testing and in vitro evaluation in a simulated body fluid (SBF) solution. According to the experimental results, the presence of Y-TZP improved the mechanical performance. Meanwhile, the BG C a–K glass, which mainly preserved its amorphous structure after sintering, provided the composites with a good apatite-forming ability in SBF. (paper)

Influence of aluminium nitride as a foaming agent on the preparation of foam glass-ceramics from high-titanium blast furnace slag

Science.gov (United States)

Shi, Huan; Feng, Ke-qin; Wang, Hai-bo; Chen, Chang-hong; Zhou, Hong-ling

2016-05-01

To effectively reuse high-titanium blast furnace slag (TS), foam glass-ceramics were successfully prepared by powder sintering at 1000°C. TS and waste glass were used as the main raw materials, aluminium nitride (AlN) as the foaming agent, and borax as the fluxing agent. The influence of the amount of AlN added (1wt%-5wt%) on the crystalline phases, microstructure, and properties of the produced foam glass-ceramics was studied. The results showed that the main crystal phases were perovskite, diopside, and augite. With increasing AlN content, a transformation from diopside to augite occurred and the crystallinity of the pyroxene phases slightly decreased. Initially, the average pore size and porosity of the foam glass-ceramics increased and subsequently decreased; similarly, their bulk density and compressive strength decreased and subsequently increased. The optimal properties were obtained when the foam glass-ceramics were prepared by adding 4wt% AlN.

A constitutive model for particulate-reinforced titanium matrix composites subjected to high strain rates and high temperatures

Directory of Open Access Journals (Sweden)

Song Wei-Dong

2013-01-01

Full Text Available Quasi-static and dynamic tension tests were conducted to study the mechanical properties of particulate-reinforced titanium matrix composites at strain rates ranging from 0.0001/s to 1000/s and at temperatures ranging from 20 °C to 650 °C Based on the experimental results, a constitutive model, which considers the effects of strain rate and temperature on hot deformation behavior, was proposed for particulate-reinforced titanium matrix composites subjected to high strain rates and high temperatures by using Zener-Hollomon equations including Arrhenius terms. All the material constants used in the model were identified by fitting Zener-Hollomon equations against the experimental results. By comparison of theoretical predictions presented by the model with experimental results, a good agreement was achieved, which indicates that this constitutive model can give an accurate and precise estimate for high temperature flow stress for the studied titanium matrix composites and can be used for numerical simulations of hot deformation behavior of the composites.

A seal analyzer for testing container integrity

International Nuclear Information System (INIS)

McDaniel, P.; Jenkins, C.

1988-01-01

This paper reports on the development of laboratory and production seal analyzer that offers a rapid, nondestructive method of assuring the seal integrity of virtually any type of single or double sealed container. The system can test a broad range of metal cans, drums and trays, membrane-lidded vessels, flexible pouches, aerosol containers, and glass or metal containers with twist-top lids that are used in the chemical/pesticide (hazardous materials/waste), beverage, food, medical and pharmaceutical industries

Investigation of Performance of SCN-1 Pure Glass as Sealant Used in SOFC

Energy Technology Data Exchange (ETDEWEB)

Liu, Wenning N.; Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

2010-03-01

As its name implies, self-healing glass seal has the potential of restoring its mechanical properties upon being reheated to stack operating temperature, even when it has experienced some cooling induced damage/crack at room temperature. Such a self-healing feature is desirable for achieving high seal reliability during thermal cycling. On the other hand, self-healing glass is also characterized by its low mechanical stiffness and high creep rate at the typical operating temperature of SOFCs. Therefore, from a design’s perspective, it is important to know the long term geometric stability and thermal mechanical behaviors of the self-healing glass under the stack operating conditions. These predictive capabilities will guide the design and optimization of a reliable sealing system that potentially utilizes self-healing glass as well as other ceramic seal components in achieving the ultimate goal of SOFC. In this report, we focused on predicting the effects of various generic seal design parameters on the stresses in the seal. For this purpose, we take the test cell used in the leakage test for compliant glass seals conducted in PNNL as our initial modeling geometry. The effect of the ceramic stopper on the geometry stability of the self-healing glass sealants is studied first. Then we explored the effect of various interfaces such as stopper and glass, stopper and PEN, as well stopper and IC plate, on the geometry stability and reliability of glass during the operating and cooling processes.

Diffraction measurements of residual stress in titanium matrix composites

International Nuclear Information System (INIS)

James, M.R.; Bourke, M.A.; Goldstone, J.A.; Lawson, A.C.

1993-01-01

Metal matrix composites develop residual strains after consolidation due to the thermal expansion mismatch between the reinforcement fiber and the matrix. X-ray and neutron diffraction measured values for the longitudinal residual stress in the matrix of four titanium MMCs are reported. For thick composites (> 6 plies) the surface stress measured by x-ray diffraction matches that determined by neutron diffraction and therefore represents the stress in the bulk region consisting of the fibers and matrix. For thin sheet composites, the surface values are lower than in the interior and increase as the outer rows of fibers are approached. While a rationale for the behavior in the thin sheet has yet to be developed, accounting for composite thickness is important when using x-ray measured values to validate analytic and finite element calculations of the residual stress state

Effect of glass-ceramic-processing cycle on the metallurgical properties of candidate alloys for actuator housings

Energy Technology Data Exchange (ETDEWEB)

Weirick, L.J.

1982-01-01

This report summarizes the results from an investigation on the effect of a glass ceramic processing cycle on the metallurgical properties of metal candidates for actuator housings. The cycle consists of a 980/sup 0/C sealing step, a 650/sup 0/C crystallization step and a 475/sup 0/C annealing step. These temperatue excursions are within the same temperature regime as annealing and heat treating processes normally employed for metals. Therefore, the effect of the processing cycle on metallurgical properties of microstructure, strength, hardness and ductility were examined. It was found that metal candidates which are single phase or solid solution alloys (such as 21-6-9, Hastelloy C-276 and Inconel 625) were not affected whereas multiphase or precipitation hardened alloys (such as Inconel 718 and Titanium ..beta..-C) were changed by the processing cycle for the glass ceramic.

Transparent Nanoporous Glass-Polymer Composite for U.S. Army Applications

Science.gov (United States)

2008-10-01

material is created by infiltrating nanoporous glass (Vycor, Corning Inc.) with different polymers. The Vycor pores (4–6 nm) are much smaller than the...glass-polymer composite to a carbon-silica composite through pyrolysis . Sotomayor et al. (12) used polyanaline-infused Vycor to produce a pH sensor...Vycor is a registered trademark of Corning , Inc., Corning , NY. 3 In this report, we will explore the processing and mechanical behavior of

Age and sex composition of seals killed by polar bears in the eastern Beaufort Sea.

Science.gov (United States)

Pilfold, Nicholas W; Derocher, Andrew E; Stirling, Ian; Richardson, Evan; Andriashek, Dennis

2012-01-01

Polar bears (Ursus maritimus) of the Beaufort Sea enter hyperphagia in spring and gain fat reserves to survive periods of low prey availability. We collected information on seals killed by polar bears (n=650) and hunting attempts on ringed seal (Pusa hispida) lairs (n=1396) observed from a helicopter during polar bear mark-recapture studies in the eastern Beaufort Sea in spring in 1985-2011. We investigated how temporal shifts in ringed seal reproduction affect kill composition and the intraspecific vulnerabilities of ringed seals to polar bear predation. Polar bears primarily preyed on ringed seals (90.2%) while bearded seals (Erignathus barbatus) only comprised 9.8% of the kills, but 33% of the biomass. Adults comprised 43.6% (150/344) of the ringed seals killed, while their pups comprised 38.4% (132/344). Juvenile ringed seals were killed at the lowest proportion, comprising 18.0% (62/344) of the ringed seal kills. The proportion of ringed seal pups was highest between 2007-2011, in association with high ringed seal productivity. Half of the adult ringed seal kills were ≥ 21 years (60/121), and kill rates of adults increased following the peak of parturition. Determination of sex from DNA revealed that polar bears killed adult male and adult female ringed seals equally (0.50, n=78). The number of hunting attempts at ringed seal subnivean lair sites was positively correlated with the number of pup kills (r(2) =0.30, P=0.04), but was not correlated with the number of adult kills (P=0.37). Results are consistent with decadal trends in ringed seal productivity, with low numbers of pups killed by polar bears in spring in years of low pup productivity, and conversely when pup productivity was high. Vulnerability of adult ringed seals to predation increased in relation to reproductive activities and age, but not gender.

Calcium phosphate glass-ceramics for bioactive coating on a {beta}-titanium alloy

Energy Technology Data Exchange (ETDEWEB)

Kasuga, T.; Nogami, M. [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Niinomi, M. [Department of Production Systems Engineering, Toyohashi University of Technology, Tenpaku-cho, Toyohashi 441-8580 (Japan)

2003-07-01

The formation of a porous coating is the decisive feature for the bio-compatibility of silica-free calcium phosphate glass ceramics on alloy surfaces like the {beta}-Ti structured Ti-29Nb-13Ta-4.6Zr used in this work. The ceramic composition is highly important: 50CaO-40P{sub 2}O{sub 5}-7Na{sub 2}O-3TiO{sub 2} glass powder produces a pore-free coating unable to bind hydroxyapatite, whereas 60CaO-30P{sub 2}O{sub 5}-7Na{sub 2}O-3TiO{sub 2} glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Tensile properties of compressed moulded Napier/glass fibre reinforced epoxy composites

Science.gov (United States)

Fatinah, T. S.; Majid, M. S. Abdul; Ridzuan, M. J. M.; Hong, T. W.; Amin, N. A. M.; Afendi, M.

2017-10-01

This paper describes the experimental investigation of the tensile properties of compressed moulded Napier grass fibres reinforced epoxy composites. The effect of treatment 5% sodium hydroxide (NaOH) concentrated solution and hybridization of Napier with CSM E-glass fibres on tensile properties was also studied. The untreated and treated Napier fibres with 25% fibre loading were fabricated with epoxy resin by a cold press process. 7% fibre loading of CSM glass fibre was hybrid as the skin layer for 18% fibre loading of untreated Napier grass fibre. The tensile tests were conducted using Universal Testing Machine in accordance with ASTM D638. The tensile properties of the untreated Napier/epoxy composites were compared with treated Napier/epoxy and untreated Napier/CSM/epoxy composites. The results demonstrated that the tensile performance of untreated Napier fibre composites was significantly improved by both of the modification; alkali treatment and glass fibre hybridization. Napier grass fibres showed promising potentials to be used as reinforcement in the polymer based composites.

Bioactivity of thermal plasma synthesized bovine hydroxyapatite/glass ceramic composites

International Nuclear Information System (INIS)

Yoganand, C P; Selvarajan, V; Rouabhia, Mahmoud; Cannillo, Valeria; Sola, Antonella

2010-01-01

Bone injuries and failures often require the inception of implant biomaterials. Research in this area is receiving increasing attention worldwide. A variety of artificial bone materials, such as metals, polymeric materials, composites and ceramics, are being explored to replace diseased bones. Calcium phosphate ceramics are currently used as biomaterials for many applications in both dentistry and orthopedics. Bioactive silicate-based glasses show a higher bioactive behaviour than calcium phosphate materials. It is very interesting to study the mixtures of HA and silicate-based glasses. In the present study; natural bovine hydroxyapatite / SiO 2 -CaO-MgO glass composites were produced using the Transferred arc plasma (TAP) melting method. TAP melting route is a brisk process of preparation of glass-ceramics in which the raw materials are melted in the plasma and crystallization of the melt occurs while cooling down at a much faster rate in relatively short processing times compared to the conventional methods of manufacture of glass ceramics/composites. It is well known that; one essential step to the understanding of the biological events occurring at the bone tissue/material interface is the biological investigation by in vitro tests. Cell lines are commonly used for biocompatibility tests, and are very efficient because of their reproducibility and culture facility. In this study, we report the results of a study on the response of primary cultures of human fibroblast cells to TAP melted bioactive glass ceramics.

Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant

Directory of Open Access Journals (Sweden)

Richard C. Petersen

2011-01-01

Full Text Available Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P<10−4, and 19.3% to 77.7% at 0.1 mm, P<10−8. Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential.

Drilling of Hybrid Titanium Composite Laminate (HTCL) with Electrical Discharge Machining.

Science.gov (United States)

Ramulu, M; Spaulding, Mathew

2016-09-01

An experimental investigation was conducted to determine the application of die sinker electrical discharge machining (EDM) as it applies to a hybrid titanium thermoplastic composite laminate material. Holes were drilled using a die sinker EDM. The effects of peak current, pulse time, and percent on-time on machinability of hybrid titanium composite material were evaluated in terms of material removal rate (MRR), tool wear rate, and cut quality. Experimental models relating each process response to the input parameters were developed and optimum operating conditions with a short cutting time, achieving the highest workpiece MRR, with very little tool wear were determined to occur at a peak current value of 8.60 A, a percent on-time of 36.12%, and a pulse time of 258 microseconds. After observing data acquired from experimentation, it was determined that while use of EDM is possible, for desirable quality it is not fast enough for industrial application.

Drilling of Hybrid Titanium Composite Laminate (HTCL with Electrical Discharge Machining

Directory of Open Access Journals (Sweden)

M. Ramulu

2016-09-01

Full Text Available An experimental investigation was conducted to determine the application of die sinker electrical discharge machining (EDM as it applies to a hybrid titanium thermoplastic composite laminate material. Holes were drilled using a die sinker EDM. The effects of peak current, pulse time, and percent on-time on machinability of hybrid titanium composite material were evaluated in terms of material removal rate (MRR, tool wear rate, and cut quality. Experimental models relating each process response to the input parameters were developed and optimum operating conditions with a short cutting time, achieving the highest workpiece MRR, with very little tool wear were determined to occur at a peak current value of 8.60 A, a percent on-time of 36.12%, and a pulse time of 258 microseconds. After observing data acquired from experimentation, it was determined that while use of EDM is possible, for desirable quality it is not fast enough for industrial application.

Quantitative morphological and compositional evaluation of laboratory prepared aluminoborosilicate glass surfaces

Energy Technology Data Exchange (ETDEWEB)

Gong, Yuxuan, E-mail: yg4@alfred.edu; Wren, Anthony W.; Mellott, Nathan P.

2015-01-01

Graphical abstract: - Highlights: • Aluminoborosilicate glass surfaces were prepared through both melting and polishing/etching and the surface composition and morphology were quantified as a function of processing method. • Glass surface morphology was quantified using PSD analysis, followed by both fractal and ABC model fitting, resulting in a comprehensive description of the spatial distribution of roughness. • All melt surfaces showed a depletion in Na, Ca, and B with respect to the bulk composition. Polished/etched surfaces showed a depletion in Na, B, and Al with respect to the bulk composition. • It was found that increasing heat treatment temperature of melt surfaces lead to a decrease in equivalent roughness and an increased spatial homogeneity of roughness while etching of polished ISG glass surfaces decreases the roughness and spatial distribution homogeneity of roughness. - Abstract: Surface finishing techniques including polishing, etching and heat treatment can modify the topography and the surface chemical composition of glasses. It is widely acknowledged that atomic force microscopy (AFM) can be used to quantify the morphology of surfaces, providing various parameters including average, peak-to-valley, and apparent root-mean-square roughness. Furthermore advanced power spectral density (PSD) analysis of AFM-derived surface profiles offers quantification of the spatial homogeneity of roughness values along different wavelengths, resulting in parameters including equivalent RMS, Hurst exponent, and fractal dimension. Outermost surface (∼8 nm) chemical composition can be quantitatively measured by X-ray photoelectron spectroscopy. In this paper, we first developed a series of surface finishing methods for an aluminoborosilicate glass system by polishing, etching or heat treatment. The chemical composition and environment of prepared glass surfaces were quantified by XPS and topographical analysis was carried out by fractal and k

Mechanical and abrasive wear characterization of bidirectional and chopped E-glass fiber reinforced composite materials

International Nuclear Information System (INIS)

Siddhartha,; Gupta, Kuldeep

2012-01-01

Highlights: ► Bi-directional and chopped E-glass fiber reinforced epoxy composites are fabricated. ► Three body abrasive wear behavior of fabricated composites has been assessed. ► Results are validated against existing microscopic models of Lancaster and Wang. ► Tensile strength of bi-directional E-glass fiber reinforced composites increases. ► Chopped glass fiber composites are found better in abrasive wear situations. -- Abstract: Bi-directional and chopped E-glass fiber reinforced epoxy composites are fabricated in five different (15, 20, 25, 30 and 35) wt% in an epoxy resin matrix. The mechanical characterization of these composites is performed. The three body abrasive wear behavior of fabricated composites has been assessed under different operating conditions. Abrasive wear characteristics of these composites are successfully analysed using Taguchi’s experimental design scheme and analysis of variance (ANOVA). The results obtained from these experiments are also validated against existing microscopic models of Ratner-Lancaster and Wang. It is observed that quite good linear relationships is held between specific wear rate and reciprocal of ultimate strength and strain at tensile fracture of these composites which is an indicative that the experimental results are in fair agreement with these existing models. Out of all composites fabricated it is found that tensile strength of bi-directional E-glass fiber reinforced composites increases because of interface strength enhancement. Chopped glass fiber reinforced composites are observed to perform better than bi-directional glass fiber reinforced composites under abrasive wear situations. The morphology of worn composite specimens has been examined by scanning electron microscopy (SEM) to understand about dominant wear mechanisms.

Glass compositions suitable for PFR wastes

International Nuclear Information System (INIS)

Boult, K.A.; Dalton, J.T.; Eccles, E.W.; Hough, A.; Marples, J.A.C.; Paige, E.L.; Sutcliffe, P.W.

1988-03-01

Previous work had identified glass compositions that were suitable for vitrifying current and future high level wastes from the Prototype Fast Reactor (PFR) fuel reprocessing plant. Further work on these glasses has shown that: a) Foaming and crystallisation can occur under certain conditions, both probably associated with the presence of iron in the waste. Either of these could lead to greater difficulties in processing. b) Inconel 690, the preferred JCM (Joule-heated Ceramic Melter) electrode material has an acceptable corrosion rate at 1200 0 C: ca 0.6mm.y -1 . c) The leach rates are unaffected by radiation damage. The density of the glass decreases slightly with α-dose, with a dependency that extrapolates, at infinite time, to an 0.13% linear expansion. d) The concentrations of the radiologically important elements Tc, Np, Pu and Am, observed in a 'repository simulation' leach test, were satisfactorily low. (author)

Modification of the Surface Topography and Composition of Ultrafine and Coarse Grained Titanium by Chemical Etching

Directory of Open Access Journals (Sweden)

Denis V. Nazarov

2017-01-01

Full Text Available In this study, we present the detailed investigation of the influence of the etching medium (acidic or basic Piranha solutions and the etching time on the morphology and surface relief of ultrafine grained (UFG and coarse grained (CG titanium. The surface relief and morphology have been studied by means of scanning electron microscopy (SEM, atomic force microscopy (AFM, and the spectral ellipsometry. The composition of the samples has been determined by X-ray fluorescence analysis (XRF and X-ray Photoelectron Spectroscopy (XPS. Significant difference in the etching behavior of UFG and CG titanium has been found. UFG titanium exhibits higher etching activity independently of the etching medium. Formed structures possess higher homogeneity. The variation of the etching medium and time leads to micro-, nano-, or hierarchical micro/nanostructures on the surface. Significant difference has been found between surface composition for UFG titanium etched in basic and acidic Piranha solution. Based on the experimental data, the possible reasons and mechanisms are considered for the formation of nano- and microstructures. The prospects of etched UFG titanium as the material for implants are discussed.

Sealed glass coating of high temperature ceramic superconductors

Science.gov (United States)

Wu, Weite; Chu, Cha Y.; Goretta, Kenneth C.; Routbort, Jules L.

1995-01-01

A method and article of manufacture of a lead oxide based glass coating on a high temperature superconductor. The method includes preparing a dispersion of glass powders in a solution, applying the dispersion to the superconductor, drying the dispersion before applying another coating and heating the glass powder dispersion at temperatures below oxygen diffusion onset and above the glass melting point to form a continuous glass coating on the superconductor to establish compressive stresses which enhance the fracture strength of the superconductor.

Glass composite waste forms for iodine confined in bismuth-embedded SBA-15

Science.gov (United States)

Yang, Jae Hwan; Park, Hwan Seo; Ahn, Do-Hee; Yim, Man-Sung

2016-11-01

The aim of this study was to stabilize bismuth-embedded SBA-15 that captured iodine gas by fabrication of monolithic waste forms. The iodine containing waste was mixed with Bi2O3 (a stabilizing additive) and low-temperature sintering glass followed by pelletizing and the sintering process to produce glass composite materials. Iodine volatility during the sintering process was significantly affected by the ratio of Bi2O3 and the glass composition. It was confirmed that BiI3, the main iodine phase within bismuth-embedded SBA-15, was effectively transformed to the mixed phases of Bi5O7I and BiOI. The initial leaching rates of iodine from the glass composite waste forms ranged 10-3-10-2 g/m2 day, showing the stability of the iodine phases encapsulated by the glassy networks. It was also observed that common groundwater anions (e.g., chloride, carbonate, sulfite, and fluoride) elevated the iodine leaching rate by anion exchange reactions. The present results suggest that the glass composite waste form of bismuth-embedded SBA-15 could be a candidate material for stable storage of 129I.

Composition effect of potassium-borate glasses on their relaxation properties

International Nuclear Information System (INIS)

Lomovskoj, V.A.; Bartenev, G.M.

1995-01-01

Relaxation processes in potassium-borate glasses have been investigated in detail for the first time. It is shown that low-temperature β-process of relaxation relating to rotational mobility of the B-O bond is the same for all potassium-borate glasses and B 2 O 3 . The process of β k -relaxation related to diffusion mobility of potassium ions depends on the composition of the glasses in the same way as α-relaxation (glass formation).12 refs., 10 figs., 2 tabs

Examination of the Thermo-mechanical Properties of E-Glass/Carbon Composites

Directory of Open Access Journals (Sweden)

Hande Sezgin

2017-12-01

Full Text Available Eight-ply E-glass, carbon and E-glass/carbon fabric-reinforced polyester based hybrid composites were manufactured in this study. A vacuum infusion system was used as the production method. Dynamic mechanical analysis, thermogravimetric analysis and differential scanning calorimetry analysis were conducted to examine the thermo-mechanical properties of composite samples. The effect of reinforcement type and different stacking sequences of fabric plies on the thermo-mechanical properties of composite samples were also investigated. Results showed that the type and alignment of reinforcement material has a signifi cant effect on the dynamic mechanical properties of composite samples.

Fabrication of slag-glass composite with controlled porosity

Directory of Open Access Journals (Sweden)

Ranko Adziski

2008-06-01

Full Text Available The preparation and performance of porous ceramics made from waste materials were investigated. Slag from thermal electrical plant Kakanj (Bosnia and Herzegovina with defined granulations: (0.500÷0.250 mm; (0.250÷0.125 mm; (0.125÷0.063 mm; (0.063÷0.045 mm and 20/10 wt.% of the waste TV screen glass with a granulation <0.063 mm were used for obtaining slag-glass composites with controlled porosity. The one produced from the slag powder fraction (0.125÷0.063 mm and 20 wt.% TV screen glass, sintered at 950°C/2h, was considered as the optimal. This system possesses open porosity of 26.8±1.0%, and interconnected pores with the size of 250–400 μm. The values of E-modulus and bending strength of this composite were 10.6±0.6 GPa and 45.7±0.7 MPa, respectively. The coefficient of thermal expansion was 8.47·10-6/°C. The mass loss in 0.1M HCl solution after 30 days was 1.2 wt.%. The permeability and the form coefficient of the porous composite were K0=0.12 Da and C0=4.53·105 m-1, respectively. The porous composite shows great potential to be used as filters, diffusers for water aeration, dust collectors, acoustic absorbers, etc.

Study of the influence of chemical composition on the pozzolanicity of soda-lime glass microparticles

International Nuclear Information System (INIS)

Sales, R.B.C.; Mohallem, N.D.S.; Aguilar, M.T.P.

2014-01-01

The use of residues presents interesting possibilities for obtaining eco-efficient concretes. Research has investigated the use of glass residue in Portland cement composite, whether as an aggregate or a supplementary material. However, there is still no consensus on the influence of the chemical composition of glass on the behaviour of the composites in which it is used. This paper aims to analyse the influence of this composition on the performance of cement composites produced with microparticles of colourless and amber glass. Pozzolanicity was assessed by means of direct tests (modified Chapelle and electrical conductivity) and indirect tests (chemical characterization, X-ray diffraction, thermo analysis and pozzolanic activity index). Most of the results show that microparticles of both types of glass display pozzolanic activity, with no significant differences between them. This indicates the potential for the use of glass microparticles as a supplementary material in cement composites. (author)

Fatigue damage propagation in unidirectional glass fibre reinforced composites

DEFF Research Database (Denmark)

Hansen, Jens Zangenberg; Alzamora Guzman, Vladimir Joel; Østergaard, R.C.

2012-01-01

bundles. The underlying mechanisms are examined using digital microscopy, and it is postulated that fatigue damage initiates due to stress concentrations between the backing (transverse) layer and the unidirectional layer, followed by a cyclic fretting and axial fibre debonding. This fretting mechanism......Damage progression in unidirectional glass fibre reinforced composites exposed to tension fatigue is investigated, and a quantitative explanation is given for the observed stiffness loss. The stiffness degradation during fatigue is directly related to fibre breaks in the load-carrying axial fibre...... needs further attention and understanding in order to improve the fatigue life-time of glass fibre reinforced composites....

Development and characterization of glass-ceramic sealants in the (CaO-Al2O3-SiO2-B2O3) system for Solid Oxide Electrolyzer Cells

International Nuclear Information System (INIS)

Khedim, Hichem; Nonnet, Helene; Mear, Francois O.

2012-01-01

The efficiency of glass-ceramic sealants plays a crucial role in Solid Oxide Electrolyzer Cell performance and durability. In order to develop suitable sealants, operating around 800 degrees C, two parent glass compositions, CAS1B and CAS2B, from the CaO-Al 2 O 3 -SiO 2 -B 2 O 3 system were prepared and explored. The thermal and physicochemical properties of the glass ceramics and their crystallization behavior were investigated by HSM. DTA and XRD analyses. The microstructure and chemical compositions of the crystalline phases were investigated by microprobe analysis. Bonding characteristic as well as chemical interactions of the parent glass with yttria-stabilized zirconia (YSZ) electrolyte and ferritic steel-based interconnect (Crofere (R)) were also investigated. The preliminary results revealed the superiority of CAS2B glass for sealing application in SOECs. The effect of minor additions of V 2 O 5 , K 2 O and TiO 2 on the thermal properties was also studied and again demonstrated the advantages of the CAS2B glass composition. Examining the influence of heat treatment on the seal behavior showed that the choice of the heating rate is a compromise between delaying the crystallization process and delaying the viscosity drop. The thermal Expansion Coefficients (TEC) obtained for the selected glass ceramic are within the desired range after the heat treatment of crystallization. The crystallization kinetic parameters of the selected glass composition were also determined under non-isothermal conditions by means of differential thermal analysis (DTA) and using the formal theory of transformations for heterogeneous nucleation. (authors)

Compositional dependence thermal and optical properties of a novel germanate glass

International Nuclear Information System (INIS)

El-Rabaie, S.; Taha, T.A.; Higazy, A.A.

2014-01-01

A series of zinc lithium germanate glasses of the composition (45−x)Li 2 O–xZnO–55GeO 2 have been synthesized via melt quenching technique. Dependencies of their thermal and optical properties on composition were investigated. It is found that the gradual replacement of Li 2 O by ZnO, decreases the glass transition temperature from 430 to 280 °C and increases the thermal stability (ΔT) of the studied glasses. The optical band gap E opt also decreases from 2.31 to 1.40 eV with increasing the mole content of ZnO

Flow and Fracture of Bulk Metallic Glass Alloys and their Composites

International Nuclear Information System (INIS)

Flores, K M; Suh, D; Howell, R; Asoka-Kumar, P; Dauskardt, R H

2001-01-01

The fracture and plastic deformation mechanisms of a Zr-Ti-Ni-Cu-Be bulk metallic glass and a composite utilizing a crystalline reinforcement phase are reviewed. The relationship between stress state, free volume and shear band formation are discussed. Positron annihilation techniques were used to confirm the predicted increase in free volume after plastic straining. Strain localization and failure were examined for a wide range of stress states. Finally, methods for toughening metallic glasses are considered. Significant increases in toughness are demonstrated for a composite bulk metallic glass containing a ductile second phase which stabilizes shear band formation and distributes plastic deformation

Preliminary results of durability testing with borosilicate glass compositions

International Nuclear Information System (INIS)

Adel-Hadadi, M.; Adiga, R.; Barkatt, Aa.

1987-01-01

This is a report on the first year of research conducted at the Vitreous State Laboratory of the Catholic University of America in support of the West Valley Demonstration Project. One objective is the vitrification of liquid waste generated by previous nuclear fuel reprocessing. This work has been directed principally at the problem of glass composition optimization. This has necessitated the development of a coordinated program of glass production, durability measurements, and processability assessment. A small-scale continuous melter has been constructed for melting uranium and thorium containing glasses and for studying glass processing characteristics. Glass viscosities have been measured over a range of temperatures. A large number of glasses have also been produced in small crucible melts. Glass durability has been assessed using four types of leach tests: MCC-3, MCC-1, IAEA/ISO, and pulsed-flow tests. Extensive data from these tests are reported. The data have led to the design of very durable glasses (comparable to the Savannah River Laboratory Defense Waste Reference Glass) which have the requisite waste loading and processing characteristics. 14 refs., 4 figs., 77 tabs

Investigation of mechanical properties of kenaf, hemp and E-glass fiber reinforced composites

Science.gov (United States)

Dinesh, Veena; Shivanand, H. K.; Vidyasagar, H. N.; Chari, V. Srinivasa

2018-04-01

Recently the use of fiber reinforced polymer composite in the automobile, aerospace overwhelming designing sectors has increased tremendously due to the ecological issues and health hazard possessed by the synthetic fiber during disposal and manufacturing. The paper presents tensile strength, flexural strength and hardness of kenaf-E glass-kenaf, hemp-E glass-hemp and kenaf-E glass-hemp fiber reinforced polyester composites. The composite plates are shaped according to the standard geometry and uni-axially loaded in order to investigate the tensile responses of each combination. In addition to the physical and mechanical properties, processing methods and application of kenaf and hemp fiber composites is also discussed.

Titanium Matrix Composite Ti/TiN Produced by Diode Laser Gas Nitriding

Directory of Open Access Journals (Sweden)

Aleksander Lisiecki

2015-01-01

Full Text Available A high power direct diode laser, emitting in the range of near infrared radiation at wavelength 808–940 nm, was applied to produce a titanium matrix composite on a surface layer of titanium alloy Ti6Al4V by laser surface gas nitriding. The nitrided surface layers were produced as single stringer beads at different heat inputs, different scanning speeds, and different powers of laser beam. The influence of laser nitriding parameters on the quality, shape, and morphology of the surface layers was investigated. It was found that the nitrided surface layers consist of titanium nitride precipitations mainly in the form of dendrites embedded in the titanium alloy matrix. The titanium nitrides are produced as a result of the reaction between molten Ti and gaseous nitrogen. Solidification and subsequent growth of the TiN dendrites takes place to a large extent at the interface of the molten Ti and the nitrogen gas atmosphere. The direction of TiN dendrites growth is perpendicular to the surface of molten Ti. The roughness of the surface layers depends strongly on the heat input of laser nitriding and can be precisely controlled. In spite of high microhardness up to 2400 HV0.2, the surface layers are crack free.

Leaching behavior of microtektite glass compositions in sea water and the effect of precipitation on glass leaching

International Nuclear Information System (INIS)

1991-01-01

In the present study it was attempted to account for the slow corrosion rates of microtektite glass in nature by comparing the leach rates of synthetic microtektite glass samples in deionized water and in sea-water, respectively. In order to obtain systematic data about leachant composition effects, leach tests were also carried out with synthetic leachant compositions enriched with respect to silica or depleted with respect to certain major components of sea-water (Mg, Ca). 47 refs., 1 fig., 5 tabs

Method and apparatus for dispensing small quantities of mercury from evacuated and sealed glass capsules

Science.gov (United States)

Grossman, Mark W.; George, William A.; Pai, Robert Y.

1985-01-01

A technique for opening an evacuated and sealed glass capsule containing a material that is to be dispensed which has a relatively high vapor pressure such as mercury. The capsule is typically disposed in a discharge tube envelope. The technique involves the use of a first light source imaged along the capsule and a second light source imaged across the capsule substantially transversely to the imaging of the first light source. Means are provided for constraining a segment of the capsule along its length with the constraining means being positioned to correspond with the imaging of the second light source. These light sources are preferably incandescent projection lamps. The constraining means is preferably a multiple looped wire support.

Dynamic Mechanical and Thermal Properties of Bagasse/Glass Fiber/Polypropylene Hybrid Composites

Directory of Open Access Journals (Sweden)

Mehdi Roohani

2016-06-01

Full Text Available This work aims to evaluate the thermal and dynamic mechanical properties of bagasse/glass fiber/polypropylene hybrid composites. Composites were prepared by the melt compounding method and their properties were characterized by differential scanning calorimetry (DSC and dynamic mechanical analysis (DMA. DSC results found that with incorporation of bagasse and glass fiber the melting temperature (Tm and the crystallisation temperature (Tc shift to higher temperatures and the degree of crystallinity (Xc increase. These findings suggest that the fibers played the role of a nucleating agent in composites. Dynamic mechanical analysis indicated that by the incorporation of bagasse and glass fiber into polypropylene, the storage modulus ( and the loss modulus ( increase whereas the mechanical loss factor (tanδ decrease. To assess the effect of reinforcement with increasing temperature, the effectiveness coefficient C was calculated at different temperature ranges and revealed that, at the elevated temperatures, improvement of mechanical properties due to the presence of fibers was more noticeable. The fiber-matrix adhesion efficiency determined by calculating of adhesion factor A in terms of the relative damping of the composite (tan δc and the polymer (tan δpand volume fraction of the fibers (Фf. Calculated adhesion factor A values indicated that by adding glass fiber to bagasse/polypropylene system, the fiber-matrix adhesion improve. Hybrid composite containing 25% bagasse and 15% glass fiber showed better fiber-matrix adhesion.

New sol-gel bioactive glass and titania composites with enhanced physico-chemical and biological properties.

Science.gov (United States)

Pawlik, Justyna; Widziołek, Magdalena; Cholewa-Kowalska, Katarzyna; Łączka, Maria; Osyczka, Anna Maria

2014-07-01

We developed TiO2 matrix composites modified by sol-gel bioactive glasses (SBG) of either high CaO content (A2) or high SiO2 content (S2). The latter were mixed with titanium dioxide (TiO2) at 75:25, 50:50, and 25:75 weight ratios and sintered at 1250°C for 2 h. We examined the effects of various types (A2 or S2) and compositional TiO2 :SBG ratios on the mechanical properties of resulting composites, their bioactivity and human bone marrow mesenchymal stem cells (MSC) response. The chemistry of SBGs influenced the phase composition, mechanical and biological properties of the composites. Rutile and titanite prevailed in A2-TiO2 composites, and rutile and crystobalite in S2-TiO2 composites. Compressive strength increased significantly for 25A2-TiO2 composites (140 MPa) compared to matrix TiO2 (58 MPa). Composites containing 50-75 wt % of either SBG displayed bioactive properties as determined by simulated body fluid test. Compared to TiO2, human bone marrow stromal cell (BMSC) viability was enhanced on the composites containing 25 wt % of either SBG, whereas the composites modified by 25 wt % of S2 enhanced alkaline phosphatase activity and mineralization in cultures treated with osteogenic inducers-dexamethasone (Dex) or bone morphogenetic protein. Increasing amounts of A2 in TiO2 matrix decreased cell viability but increased collagen deposition and mineralized matrix production by BMSC. Considering the physico-chemical and biological properties of the presented composites, the modification of TiO2 with SBG may prove useful strategy in several bone tissue related regeneration strategies. © 2013 Wiley Periodicals, Inc.

Electrochemical process for the manufacturing of titanium alloy matrix composites

Directory of Open Access Journals (Sweden)

V. Soare

2009-07-01

Full Text Available The paper presents a new method for precursors’ synthesis of titanium alloys matrix composites through an electrochemical process in molten calcium chloride. The cathode of the cell was made from metallic oxides powders and reinforcement ceramic particles, which were pressed and sintered into disk form and the anode from graphite. The process occurred at 850 °C, in two stages, at 2,7 / 3,2 V: the ionization of the oxygen in oxides and the reduction with calcium formed by electrolysis of calcium oxide fed in the electrolyte. The obtained composite precursors, in a form of metallic sponge, were consolidated by pressing and sintering. Chemical and structural analyses on composites samples were performed.

Effects of glass composition on the residual rate of alteration and modelling parameters

International Nuclear Information System (INIS)

Fleury, Benjamin

2013-01-01

This PhD thesis deals with the long-term behavior of the French nuclear glasses R7T7. An experiment plan (based on 27 glass compositions) is developed for studying the effect of glass composition on the residual rate of alteration. The impact of Mg-phase precipitation on glass alteration is also studied and several modelling exercises are performed. There is one order of magnitude between the different measurements (rate or pH...) associated with the different glass compositions. The statistical treatment of these measurements results in predictive equations and several observable trends are valid for all materials with a composition complying with the experiment plan conditions. The effect of Si, Na, B and Al on alteration (.i.e, gel and secondary phase's formation, pH) is confirmed, the influence of Zn, Zr and Ni-Co is evidenced. The role of Cr has to be clarified. Experiments show that glass alteration rate in underground water, which contains high level of Ca and Mg, is one order of magnitude higher than in the case of pure water. The glass composition plays the same role for the alteration in the two types of solution. During alteration, the late addition of Mg introduces a time lag in the resumption response because silicon is first provided from partial dissolution of the previously-formed alteration gel. The nucleation process does not limit Mg-silicate precipitation whereas a pH above 8-8.5 is necessary for Mg-silicate precipitation. The glass alteration rate can be a limiting factor if the quantity of Mg supplied to the reaction is enough. The Mg silicate phase seems to have systematically a molar ratio Mg/Si between 0.2 and 0.4. It is also shown that the air tightness of the reactor influences the rate of dissolution of CO 2 in the solution leading to a decrease of pH. Finally, modelling exercises with GRAAL show promising results. Such modelling is required in order to extend the prediction of the long-term alteration behavior to different glass

Investigation of morphology and bioactive properties of composite coating of HA/vinyl acetate on pure titanium

International Nuclear Information System (INIS)

Afshar, Abdollahe; Yousefpour, Mardali; Xiudong, Yang; Li Xudong; Yang Bangcheng; Wu Yao; Chen Jiyong; Zhang Xingdong

2006-01-01

Electrochemical co-deposition approach was expanded to prepare composite bio-ceramic coating of hydroxyapatite (HA)/polyvinyl acetate on the surface of titanium. The role is to improve the bioactive and crystallization properties. The results of XRD, XPS, SEM and TEM characterization showed that by increasing amount of vinyl acetate in the composite bio-ceramic coating before and after immersing in the simulated body fluid (SBF), an oriented growth of HA planes on the (0 0 2) direction had been observed on titanium substrate. Also significant surface morphology changes were obtained

Bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber composite: biomechanical properties and biocompatibility.

Science.gov (United States)

Qiao, Bo; Li, Jidong; Zhu, Qingmao; Guo, Shuquan; Qi, Xiaotong; Li, Weichao; Wu, Jun; Liu, Yang; Jiang, Dianming

2014-01-01

An ideal bone plate for internal fixation of bone fractures should have good biomechanical properties and biocompatibility. In this study, we prepared a new nondegradable bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber (n-HA/PA66/GF) composite. A breakage area on the n-HA/PA66/GF plate surface was characterized by scanning electron microscopy. Its mechanical properties were investigated using bone-plate constructs and biocompatibility was evaluated in vitro using bone marrow-derived mesenchymal stem cells. The results confirmed that adhesion between the n-HA/PA66 matrix and the glass fibers was strong, with only a few fibers pulled out at the site of breakage. Fractures fixed by the n-HA/PA66/GF plate showed lower stiffness and had satisfactory strength compared with rigid fixation using a titanium plate. Moreover, the results with regard to mesenchymal stem cell morphology, MTT assay, Alizarin Red S staining, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction for alkaline phosphatase and osteocalcin showed that the n-HA/PA66/GF composite was suitable for attachment and proliferation of mesenchymal stem cells, and did not have a negative influence on matrix mineralization or osteogenic differentiation of mesenchymal stem cells. These observations indicate that the n-HA/PA66/GF plate has good biomechanical properties and biocompatibility, and may be considered a new option for internal fixation in orthopedic surgery.

Corrosion of gold alloys and titanium in artificial saliva

International Nuclear Information System (INIS)

Brune, D.; Evje, D.

1982-01-01

Two types of gold alloys and one type of pure titanium have been submitted to corrosion in artificial saliva for periods of up to about 2 months. The release of copper, gold and silver from the gold alloys as well as titanium from the titanium matrix was measured with nuclear tracer technique. The physical/chemical state of the corrosion products of gold alloys referring to the ionic state or presence in particulate form has been examined retaining the particulate matter on a glass filter. Copper was observed to be mainly present in the ionic state. Considerable amounts of gold were observed to be retained on the glass filter explained by the presence of gold in particulate form or as a compentent of a dispersed collloidal phase. The estimation of the release of titanium was registered by the tracer nuclide 46 Sc assuming particulate matter to be deteriorated from the titanium surface. (author)

Age and sex composition of seals killed by polar bears in the eastern Beaufort Sea.

Directory of Open Access Journals (Sweden)

Nicholas W Pilfold

Full Text Available Polar bears (Ursus maritimus of the Beaufort Sea enter hyperphagia in spring and gain fat reserves to survive periods of low prey availability. We collected information on seals killed by polar bears (n=650 and hunting attempts on ringed seal (Pusa hispida lairs (n=1396 observed from a helicopter during polar bear mark-recapture studies in the eastern Beaufort Sea in spring in 1985-2011. We investigated how temporal shifts in ringed seal reproduction affect kill composition and the intraspecific vulnerabilities of ringed seals to polar bear predation.Polar bears primarily preyed on ringed seals (90.2% while bearded seals (Erignathus barbatus only comprised 9.8% of the kills, but 33% of the biomass. Adults comprised 43.6% (150/344 of the ringed seals killed, while their pups comprised 38.4% (132/344. Juvenile ringed seals were killed at the lowest proportion, comprising 18.0% (62/344 of the ringed seal kills. The proportion of ringed seal pups was highest between 2007-2011, in association with high ringed seal productivity. Half of the adult ringed seal kills were ≥ 21 years (60/121, and kill rates of adults increased following the peak of parturition. Determination of sex from DNA revealed that polar bears killed adult male and adult female ringed seals equally (0.50, n=78. The number of hunting attempts at ringed seal subnivean lair sites was positively correlated with the number of pup kills (r(2 =0.30, P=0.04, but was not correlated with the number of adult kills (P=0.37.Results are consistent with decadal trends in ringed seal productivity, with low numbers of pups killed by polar bears in spring in years of low pup productivity, and conversely when pup productivity was high. Vulnerability of adult ringed seals to predation increased in relation to reproductive activities and age, but not gender.

Mechanical Properties of Abutments: Resin-Bonded Glass Fiber-Reinforced Versus Titanium.

Science.gov (United States)

Bassi, Mirko Andreasi; Bedini, Rosells; Pecci, Raffaela; Ioppolo, Pietro; Laritano, Dorina; Carinci, Francesco

2016-01-01

The clinical success and longevity of endosseous implants, after their prosthetic finalization, mainly depends on mechanical factors. Excessive mechanical stress has been shown to cause initial bone loss around implants in the presence of a rigid implant-prosthetic connection. The implant abutments are manufactured with high elastic modulus materials such as titanium, steel, precious alloys, or esthetic ceramics. These materials do not absorb any type of shock from the chewing loads or ensure protection of the bone-implant interface, especially when the esthetic restorative material is ceramic rather than composite resin. The mechanical resistance to cyclical load was evaluated in a tooth-colored fiber-reinforced abutment prototype (TCFRA) and compared to that of a similarly shaped titanium abutment (TA). Eight TCFRAs and eight TAs were adhesively cemented on as many titanium implants. The swinging the two types of abutments showed during the application of sinusoidal load was also analyzed. In the TA group, fracture and deformation occurred in 12.5% of samples, while debonding occurred in 62.5%. In the TCFRA group, only debonding was present, in 37.5% of samples. In comparison to the TAs, the TCFRAs exhibited greater swinging during the application of sinusoidal load. In the TA group extrusion prevailed, whereas in the TCFRA group intrusion was more frequent. TCFRA demonstrated a greater elasticity than did TAs to the flexural load, absorbing part of the transversal load applied on the fixture during the chewing function and thus reducing the stress on the bone-implant interface.

Fatigue of hybrid glass/carbon composites: 3D computational studies

DEFF Research Database (Denmark)

Dai, Gaoming; Mishnaevsky, Leon

2014-01-01

3D computational simulations of fatigue of hybrid carbon/glass fiber reinforced composites is carried out using X-FEM and multifiber unit cell models. A new software code for the automatic generation of unit cell multifiber models of composites with randomly misaligned fibers of various properties...... and geometrical parameters is developed. With the use of this program code and the X-FEM method, systematic investigations of the effect of microstructure of hybrid composites (fraction of carbon versus glass fibers, misalignment, and interface strength) and the loading conditions (tensile versus compression...... cyclic loading effects) on fatigue behavior of the materials are carried out. It was demonstrated that the higher fraction of carbon fibers in hybrid composites is beneficial for the fatigue lifetime of the composites under tension-tension cyclic loading, but might have negative effect on the lifetime...

DWPF waste glass Product Composition Control System

International Nuclear Information System (INIS)

Brown, K.G.; Postles, R.L.

1992-01-01

The Defense Waste Processing Facility (DWPF) will be used to blend aqueous radwaste (PHA) with solid radwaste (Sludge) in a waste receipt vessel (the SRAT). The resulting SRAT material is transferred to the SME an there blended with ground glass (Frit) to produce a batch of melter feed slurry. The SME material is passed to a hold tank (the MFT) which is used to continuously feed the DWPF melter. The melter. The melter produces a molten glass wasteform which is poured into stainless steel canisters for cooling and, ultimately, shipment to and storage in a geologic repository. The Product Composition Control System (PCCS) is the system intended to ensure that the melt will be processible and that the glass wasteform will be acceptable. This document provides a description of this system

Hot isostatic pressing of glass-zeolite composites

International Nuclear Information System (INIS)

Hash, M.C.; Pereira, C.; Lewis, M.A.

1996-01-01

Glass-zeolite waste forms are being developed for immobilizing the chloride waste salt generated from the electrometallurgical treatment of spent fuel. Glass-zeolite composites with high densities were made using hot isostatic pressing (HIP) techniques. Processing parameters were investigated to yield desirable structural ceramic properties such as mechanical, chemical, and thermal stability. Limits for these parameters were determined by differential thermal and thermogravimetric analysis. The resulting ceramic properties such as bulk density, open or apparent porosity, and leach resistance were determined. In addition, phase equilibria and particle-size distribution were observed by optical light and electron microscopy. Pre-HIP processing techniques were also studied to ensure intimate mixing of the glass and zeolite powders. Particle size distributions resulting from dry blending procedure are appropriate for needed flow and packing characteristics

Assessing the Validity of the Simplified Potential Energy Clock Model for Modeling Glass-Ceramics

Energy Technology Data Exchange (ETDEWEB)

Jamison, Ryan Dale [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grillet, Anne M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stavig, Mark E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Strong, Kevin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dai, Steve Xunhu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-10-01

Glass-ceramic seals may be the future of hermetic connectors at Sandia National Laboratories. They have been shown capable of surviving higher temperatures and pressures than amorphous glass seals. More advanced finite-element material models are required to enable model-based design and provide evidence that the hermetic connectors can meet design requirements. Glass-ceramics are composite materials with both crystalline and amorphous phases. The latter gives rise to (non-linearly) viscoelastic behavior. Given their complex microstructures, glass-ceramics may be thermorheologically complex, a behavior outside the scope of currently implemented constitutive models at Sandia. However, it was desired to assess if the Simplified Potential Energy Clock (SPEC) model is capable of capturing the material response. Available data for SL 16.8 glass-ceramic was used to calibrate the SPEC model. Model accuracy was assessed by comparing model predictions with shear moduli temperature dependence and high temperature 3-point bend creep data. It is shown that the model can predict the temperature dependence of the shear moduli and 3- point bend creep data. Analysis of the results is presented. Suggestions for future experiments and model development are presented. Though further calibration is likely necessary, SPEC has been shown capable of modeling glass-ceramic behavior in the glass transition region but requires further analysis below the transition region.

Barium boron silicate glass-ceramic for use as sealant in planar SOFC

International Nuclear Information System (INIS)

Silva, M.J.; Castanho, S.R.H. Mello; Reis, S.T.

2012-01-01

Glass-ceramic seals play an important role in the performance of the solid oxide fuel cell (SOFC). In this work glass-ceramic seals are discussed from the point of view of the thermal behavior of the glass and the electrochemical parameters obtained from polarization curves such as corrosion current densities (i corr ), and corrosion potential (E corr ). A seal material must have a combination of thermal-mechanical and electrochemical properties in order to seal cell components and stacks and prevent side reactions. It must be stable in oxidizing and reducing atmospheres and withstand thermal cycles between room temperature and the cell operating temperature (800 to 900°C). Glass-ceramics in the system BaO- B 2 O 3 -Al 2 O 3 -SiO 2 were investigated and compared from the point of view of sealing ability. Dilatometric analysis, thermal stability against crystallization, microstructure and electrochemical durability are discussed. (author)

Glass composition and solution speciation effects on stage III dissolution

International Nuclear Information System (INIS)

Trivelpiece, Cory L.; Rice, Jarret A.; Pantano, Carlo G.

2017-01-01

To understand and mitigate the onset of Stage III corrosion of multicomponent oxides waste glasses. Stage III refers to a resumption of the high initial rate of glass dissolution in some glass samples that have otherwise exhibited dissolution at the much lower residual rate for a long time (Stage II). Although the onset of Stage III is known to occur concurrently with the precipitation of particular alteration products, the root cause of the transition is still unknown. Certain glass compositions (notably AFCI) and high pH environmental conditions are also associated with this observed transition.

Glass composition and solution speciation effects on stage III dissolution

Energy Technology Data Exchange (ETDEWEB)

Trivelpiece, Cory L. [Pennsylvania State Univ., University Park, PA (United States); Rice, Jarret A. [Pennsylvania State Univ., University Park, PA (United States); Pantano, Carlo G. [Pennsylvania State Univ., University Park, PA (United States)

2017-10-03

To understand and mitigate the onset of Stage III corrosion of multicomponent oxides waste glasses. Stage III refers to a resumption of the high initial rate of glass dissolution in some glass samples that have otherwise exhibited dissolution at the much lower residual rate for a long time (Stage II). Although the onset of Stage III is known to occur concurrently with the precipitation of particular alteration products, the root cause of the transition is still unknown. Certain glass compositions (notably AFCI) and high pH environmental conditions are also associated with this observed transition.

Preparation, mechanical, and in vitro properties of glass fiber-reinforced polycarbonate composites for orthodontic application.

Science.gov (United States)

Tanimoto, Yasuhiro; Inami, Toshihiro; Yamaguchi, Masaru; Nishiyama, Norihiro; Kasai, Kazutaka

2015-05-01

Generally, orthodontic treatment uses metallic wires made from stainless steel, cobalt-chromium-nickel alloy, β-titanium alloy, and nickel-titanium (Ni-Ti) alloy. However, these wires are not esthetically pleasing and may induce allergic or toxic reactions. To correct these issues, in the present study we developed glass-fiber-reinforced plastic (GFRP) orthodontic wires made from polycarbonate and E-glass fiber by using pultrusion. After fabricating these GFRP round wires with a diameter of 0.45 mm (0.018 inch), we examined their mechanical and in vitro properties. To investigate how the glass-fiber diameter affected their physical properties, we prepared GFRP wires of varying diameters (7 and 13 µm). Both the GFRP with 13-µm fibers (GFRP-13) and GFRP with 7 µm fibers (GFRP-7) were more transparent than the metallic orthodontic wires. Flexural strengths of GFRP-13 and GFRP-7 were 690.3 ± 99.2 and 938.1 ± 95.0 MPa, respectively; flexural moduli of GFRP-13 and GFRP-7 were 25.4 ± 4.9 and 34.7 ± 7.7 GPa, respectively. These flexural properties of the GFRP wires were nearly equivalent to those of available Ni-Ti wires. GFRP-7 had better flexural properties than GFRP-13, indicating that the flexural properties of GFRP increase with decreasing fiber diameter. Using thermocycling, we found no significant change in the flexural properties of the GFRPs after 600 or 1,200 cycles. Using a cytotoxicity detection kit, we found that the glass fiber and polycarbonate components comprising the GFRP were not cytotoxic within the limitations of this study. We expect this metal-free GFRP wire composed of polycarbonate and glass fiber to be useful as an esthetically pleasing alternative to current metallic orthodontic wire. © 2014 Wiley Periodicals, Inc.

Property-Composition-Temperature Modeling of Waste Glass Melt Data Subject to a Randomization Restriction

International Nuclear Information System (INIS)

Piepel, Gregory F.; Heredia-Langner, Alejandro; Cooley, Scott K.

2008-01-01

Properties such as viscosity and electrical conductivity of glass melts are functions of melt temperature as well as glass composition. When measuring such a property for several glasses, the property is typically measured at several temperatures for one glass, then at several temperatures for the next glass, and so on. This data-collection process involves a restriction on randomization, which is referred to as split-plot experiment. The split-plot data structure must be accounted for in developing property-composition-temperature models and the corresponding uncertainty equations for model predictions. Instead of ordinary least squares (OLS) regression methods, generalized least squares (GLS) regression methods using restricted maximum likelihood (REML) estimation must be used. This article describes the methodology for developing property-composition-temperature models and corresponding prediction uncertainty equations using the GLS/REML regression approach. Viscosity data collected on 197 simulated nuclear waste glasses are used to illustrate the GLS/REML methods for developing a viscosity-composition-temperature model and corresponding equations for model prediction uncertainties. The correct results using GLS/REML regression are compared to the incorrect results obtained using OLS regression

High-frequency characteristics of glass/ceramic composite and alumina multilayer structures

International Nuclear Information System (INIS)

Niwa, K.; Suzuki, H.; Yokoyama, H.; Kamechara, N.; Tsubone, K.; Tanisawa, H.; Sugiki, H.

1990-01-01

This paper reports the transmission characteristics of glass/ceramic composite (borosilicate glass/alumina) and alumina multilayer structures examined. The triplate stripline formed in the glass/ceramic multilayer shows low conductor and dielectric loss. Alumina multilayer, however, has twice the transmission loss at 10 GHz, because the resistivity of W in the alumina multilayer is higher than the Cu in the glass/ceramic multilayer. Crosstalk between striplines in the glass/ceramics is less than -80 dB up to 11 GHz and 9 GHz for alumina

Thermal Diffusivity and Thermal Conductivity of Dispersed Glass Sphere Composites Over a Range of Volume Fractions

Science.gov (United States)

Carson, James K.

2018-06-01

Glass spheres are often used as filler materials for composites. Comparatively few articles in the literature have been devoted to the measurement or modelling of thermal properties of composites containing glass spheres, and there does not appear to be any reported data on the measurement of thermal diffusivities over a range of filler volume fractions. In this study, the thermal diffusivities of guar-gel/glass sphere composites were measured using a transient comparative method. The addition of the glass beads to the gel increased the thermal diffusivity of the composite, more than doubling the thermal diffusivity of the composite relative to the diffusivity of the gel at the maximum glass volume fraction of approximately 0.57. Thermal conductivities of the composites were derived from the thermal diffusivity measurements, measured densities and estimated specific heat capacities of the composites. Two approaches to modelling the effective thermal diffusivity were considered.

Chemical composition measurements of the low activity waste (LAW) EPA-Series glasses

Energy Technology Data Exchange (ETDEWEB)

Fox, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-03-01

In this report, the Savannah River National Laboratory provides chemical analysis results for a series of simulated low activity waste glasses provided by Pacific Northwest National Laboratory as part of an ongoing development task. The measured chemical composition data are reported and compared with the targeted values for each component for each glass. A detailed review showed no indications of errors in the preparation or measurement of the study glasses. All of the measured sums of oxides for the study glasses fell within the interval of 100.2 to 100.8 wt %, indicating recovery of all components. Comparisons of the targeted and measured chemical compositions showed that the measured values for the glasses met the targeted concentrations within 10% for those components present at more than 5 wt %.

Elemental compositions of suspended particles released in glass manufacture

Energy Technology Data Exchange (ETDEWEB)

Mamuro, T; Mizohata, A; Kubota, T [Radiation Center of Osaka Prefecture, Sakai (Japan)

1980-03-01

Suspended particles released in glass manufacture were subjected to multielement analysis by means of instrumental neutron activation method and energy dispersive X-ray fluorescence spectrometry. Suspended particles emitted from glass manufacture generally consist of both particles emitted from glass fusion and those produced through fuel combustion (mainly oil combustion). Elemental compositions of suspended particles emitted from glass fusion were found to be strongly dependent on the kind and recipe of raw materials and additives. Of the various metallic elements involved in suspended particles emitted from glass fusion, the elements, As, Se, Cd, Sb, Pb and so on are regarded to produce the most serious air pollution. The amount of emission of these elements to the environment is, howerer, quite varied from manufacturer to manufacturer. The replacement of electric furnace by oil combustion in opal glass manufacture remarkably reduced the emission of metallic elements to the environment.

Titanium by design: TRIP titanium alloy

Science.gov (United States)

Tran, Jamie

Motivated by the prospect of lower cost Ti production processes, new directions in Ti alloy design were explored for naval and automotive applications. Building on the experience of the Steel Research Group at Northwestern University, an analogous design process was taken with titanium. As a new project, essential kinetic databases and models were developed for the design process and used to create a prototype design. Diffusion kinetic models were developed to predict the change in phase compositions and microstructure during heat treatment. Combining a mobility database created in this research with a licensed thermodynamic database, ThermoCalc and DICTRA software was used to model kinetic compositional changes in titanium alloys. Experimental diffusion couples were created and compared to DICTRA simulations to refine mobility parameters in the titanium mobility database. The software and database were able to predict homogenization times and the beta→alpha plate thickening kinetics during cooling in the near-alpha Ti5111 alloy. The results of these models were compared to LEAP microanalysis and found to be in reasonable agreement. Powder metallurgy was explored using SPS at GM R&D to reduce the cost of titanium alloys. Fully dense Ti5111 alloys were produced and achieved similar microstructures to wrought Ti5111. High levels of oxygen in these alloys increased the strength while reducing the ductility. Preliminary Ti5111+Y alloys were created, where yttrium additions successfully gettered excess oxygen to create oxides. However, undesirable large oxides formed, indicating more research is needed into the homogeneous distribution of the yttrium powder to create finer oxides. Principles established in steels were used to optimize the beta phase transformation stability for martensite transformation toughening in titanium alloys. The Olson-Cohen kinetic model is calibrated to shear strains in titanium. A frictional work database is established for common alloying

Thermal expansion at low temperatures of glass-ceramics and glasses

Energy Technology Data Exchange (ETDEWEB)

White, G K [National Measurement Lab., Sydney (Australia)

1976-08-01

The linear thermal expansion coefficient, ..cap alpha.., has been measured from 2 to 32 K and from 55 to 90 K for a machineable glass-ceramic, an 'ultra-low expansion' titanium silicate glass (Corning ULE), and ceramic glasses (Cer-Vit and Zerodur), and for glassy carbon. ..cap alpha.. is negative for the ultra-low expansion materials below 100 K, as for pure vitreous silica. Comparative data are reported for ..cap alpha..-quartz , ..cap alpha..-cristobalite, common opal, and vitreous silica.

Experimental Investigation on Mechanical Properties of Hemp/E-Glass Fabric Reinforced Polyester Hybrid Composites

Directory of Open Access Journals (Sweden)

M R SANJAY

2016-09-01

Full Text Available This research work has been focusing on Hemp fibers has an alternative reinforcement for fiber reinforced polymer composites due to its eco-friendly and biodegradable characteristics. This work has been carried out to evaluate the mechanical properties of hemp/E-glass fabrics reinforced polyester hybrid composites. Vacuum bagging method was used for the preparation of six different kinds of hemp/glass fabrics reinforced polyester composite laminates as per layering sequences. The tensile, flexural, impact and water absorption tests of these hybrid composites were carried out experimentally according to ASTM standards. It reveals that an addition of E-glass fabrics with hemp fabrics can increase the mechanical properties of composites and decrease the water absorption of the hybrid composites.

Hydrogel/bioactive glass composites for bone regeneration applications: Synthesis and characterisation

International Nuclear Information System (INIS)

Killion, John A.; Kehoe, Sharon; Geever, Luke M.; Devine, Declan M.; Sheehan, Eoin; Boyd, Daniel; Higginbotham, Clement L.

2013-01-01

Due to the deficiencies of current commercially available biological bone grafts, alternative bone graft substitutes have come to the forefront of tissue engineering in recent times. The main challenge for scientists in manufacturing bone graft substitutes is to obtain a scaffold that has sufficient mechanical strength and bioactive properties to promote formation of new tissue. The ability to synthesise hydrogel based composite scaffolds using photopolymerisation has been demonstrated in this study. The prepared hydrogel based composites were characterised using techniques including Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray spectrometry (EDX), rheological studies and compression testing. In addition, gel fraction, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), porosity and swelling studies of the composites were carried out. It was found that these novel hydrogel bioglass composite formulations did not display the inherent brittleness that is typically associated with bioactive glass based bone graft materials and exhibited enhanced biomechanical properties compared to the polyethylene glycol hydrogel scaffolds along. Together, the combination of enhanced mechanical properties and the deposition of apatite on the surface of these hydrogel based composites make them an ideal candidate as bone graft substitutes in cancellous bone defects or low load bearing applications. Highlights: • Young's modulus increases with the addition of bioactive glasses. • Hydrogel based composites formed an apatite layer in simulated body fluid. • Storage modulus increases with addition of bioactive glasses. • Compressive strength is dependent on molecular weight and bioactive glass loading

Effect of Nb2O5 doping on improving the thermo-mechanical stability of sealing interfaces for solid oxide fuel cells.

Science.gov (United States)

Zhang, Qi; Du, Xinhang; Tan, Shengwei; Tang, Dian; Chen, Kongfa; Zhang, Teng

2017-07-13

Nb 2 O 5 is added to a borosilicate sealing system to improve the thermo-mechanical stability of the sealing interface between the glass and Fe-Cr metallic interconnect (Crofer 22APU) in solid oxide fuel cells (SOFCs). The thermo-mechanical stability of the glass/metal interface is evaluated experimentally as well as by using a finite element analysis (FEA) method. The sealing glass doped with 4 mol.% Nb 2 O 5 shows the best thermo-mechanical stability, and the sealing couple of Crofer 22APU/glass/GDC (Gd 0.2 Ce 0.8 O 1.9 ) remains intact after 50 thermal cycles. In addition, all sealing couples show good joining after being held at 750 °C for 1000 h. Moreover, the possible mechanism on the thermo-mechanical stability of sealing interface is investigated in terms of stress-based and energy-based perspectives.

Structural considerations in design of lightweight glass-fiber composite pressure vessels

Science.gov (United States)

Faddoul, J. R.

1973-01-01

The design concepts used for metal-lined glass-fiber composite pressure vessels are described, comparing the structural characteristics of the composite designs with each other and with homogeneous metal pressure vessels. Specific design techniques and available design data are identified. The discussion centers around two distinctly different design concepts, which provide the basis for defining metal lined composite vessels as either (1) thin-metal lined, or (2) glass fiber reinforced (GFR). Both concepts are described and associated development problems are identified and discussed. Relevant fabrication and testing experience from a series of NASA-Lewis Research Center development efforts is presented.

Frequency and deflection analysis of cenosphere/glass fiber interply hybrid composite cantilever beam

Science.gov (United States)

Bharath, J.; Joladarashi, Sharnappa; Biradar, Srikumar; Kumar, P. Naveen

2018-04-01

Interply hybrid laminates contain plies made of two or more different composite systems. Hybrid composites have unique features that can be used to meet specified design requirements in a more cost-effective way than nonhybrid composites. They offer many advantages over conventional composites including balanced strength and stiffness, enhanced bending and membrane mechanical properties, balanced thermal distortion stability, improved fatigue/impact resistance, improved fracture toughness and crack arresting properties, reduced weight and cost. In this paper an interply hybrid laminate composite containing Cenosphere reinforced polymer composite core and glass fiber reinforced polymer composite skin is analysied and effect of volume fraction of filler on frequency and load v/s deflection of hybrid composite are studied. Cenosphere reinforced polymer composite has increased specific strength, specific stiffness, specific density, savings in cost and weight. Glass fiber reinforced polymer composite has higher torsional rigidity when compared to metals. These laminate composites are fabricated to meet several structural applications and hence there is a need to study their vibration and deflection properties. Experimental investigation starts with fabrication of interply hybrid composite with cores of cenosphere reinforced epoxy composite volume fractions of CE 15, CE 25, CE15_UC as per ASTM E756-05C, and glasss fiber reinforced epoxy skin, cast product of required dimension by selecting glass fibre of proper thickness which is currently 0.25mm E-glass bidirectional woven glass fabric having density 2500kg/m3, in standard from cast parts of size 230mmX230mmX5mm in an Aluminum mould. Modal analysis of cantilever beam is performed to study the variation of natural frequency with strain gauge and the commercially available Lab-VIEW software and deflection in each of the cases by optical Laser Displacement Measurement Sensor to perform Load versus Deflection Analysis

Effect of fiber content on the properties of glass fiber-phenolic matrix composite

International Nuclear Information System (INIS)

Zaki, M.Y.; Shahid, M.R.; Subhani, T.; Sharif, M.N.

2003-01-01

Glass fiber-Phenolic matrix composite is used for the manufacturing of parts /components related to electronic and aerospace industry due to its high strength, dimensional stability and excellent electrical insulation properties. The evaluation of this composite material is necessary prior to make parts/components of new designs. In the present research, thermosetting phenolic plastic was reinforced with E-glass fiber in different fiber-to-resin ratios to produce composites of different compositions. Mechanical and electrical properties of these composite materials were evaluated with reference to the effect of fiber content variation in phenolic resin. (author)

Materials Characterisation of Glass/epoxy Composites - Focusing on Process Conditions

DEFF Research Database (Denmark)

Jakobsen, Johnny; Lyckegaard, Anders; Jensen, Erik Appel

2013-01-01

Predicting the behaviour of fibre reinforced polymer composites taking the process conditions into account involves advanced modelling techniques and an extensive materials characterisation. The materials characterisation of a chopped strand mat glass/epoxy composite has been the focus...

Thermochemical stability of zirconia-titanium nitride as mixed ionic-electronic composites

DEFF Research Database (Denmark)

Silva, P. S. M.; Esposito, V.; Marani, D.

2018-01-01

Dense zirconia (8% molar yttria-stabilized ZrO2)-titanium nitride (TiN) composites are fabricated to obtain mixed ionic-electronic conducting ceramic systems with high degree of electronic and thermal conductivity. The composites are consolidated by spark plasma sintering (SPS), starting from pure...... the composites, high electrical conductivity is attained. Samples exhibit metallic behavior, showing an unexpected percolation of TiN in the YSZ matrix for volume fraction ≤ 25 wt% (27 vol%). Chemical degradation and electrical properties of the compounds were monitored under oxidative (air) and inert (Ar...... transport properties of the composite can be tuned by both the relative volume fraction of phases and controlled oxidative treatments. Adjusting such parameters different electric behaviors were observed ranging from predominant electronic conductors, to temperature-independent resistivity...

Chemical and Oxygen Isotopic Composition of Roman and Late Antique Glass from Northern Greece

Directory of Open Access Journals (Sweden)

Alberta Silvestri

2017-01-01

Full Text Available The present paper emphasizes the importance of measuring the oxygen isotopic and chemical compositions of ancient glass, in order to constrain some features such as age, raw materials, and production technologies and to identify the “fingerprint” of local productions. In this context, thirty-nine Roman and late Antique glass samples and eight chert samples from northern Greece were selected and analysed for their oxygen isotopic and chemical compositions. Results show that the majority of glass samples are produced using natron as flux and have δ18O values of about 15.5‰, plus or minus a few tenths of one per mil, suggesting that raw materials probably come from Levantine area. Four samples are heavily enriched in 18O, and their chemical composition clearly shows that they were made with soda plant ash as flux. Isotopic and chemical data of Greek chert samples support the hypothesis of local production of the above samples. About half of the glass samples have chemical compositions, which allow their age to be constrained to the late Antique period. For the remaining glass, similarities with literature compositional groups are reported and discussed.

Effect of composition on peraluminous glass properties: An application to HLW containment

Energy Technology Data Exchange (ETDEWEB)

Piovesan, V. [CEA, DEN, DTCD, SECM, LDMC – Marcoule, F-30207 Bagnols sur Cèze (France); CNRS, CEMHTI UPR3079, Univ. Orléans, F-45071 Orléans (France); Bardez-Giboire, I., E-mail: isabelle.giboire@cea.fr [CEA, DEN, DTCD, SECM, LDMC – Marcoule, F-30207 Bagnols sur Cèze (France); Perret, D. [CEA, DEN, DTCD, SECM, LDMC – Marcoule, F-30207 Bagnols sur Cèze (France); Montouillout, V.; Pellerin, N. [CNRS, CEMHTI UPR3079, Univ. Orléans, F-45071 Orléans (France)

2017-01-15

Part of the Research and Development program concerning high level nuclear waste (HLW) glasses aims to assess new glass formulations able to incorporate a high waste content with enhanced properties in terms of thermal stability, chemical durability, and process ability. This study focuses on peraluminous glasses of the SiO{sub 2} – Al{sub 2}O{sub 3} – B{sub 2}O{sub 3} – Na{sub 2}O – Li{sub 2}O – CaO – La{sub 2}O{sub 3} system, defined by an excess of aluminum ions Al{sup 3+} in comparison with modifier elements such as Na{sup +}, Li{sup +} or Ca{sup 2+}. To understand the effect of composition on physical properties of glasses (viscosity, density, T{sub g}), a Design Of Experiments (DOE) approach was applied to investigate the peraluminous glass domain. The influence of each oxide was quantified to build predictive models for each property. Lanthanum and lithium oxides appear to be the most influential factors on peraluminous glass properties. - Highlights: • A Design of Experiment approach to link composition and glass properties. • Adding alkali decreases glass transition temperature. • Adding La{sub 2}O{sub 3} strongly decreases glass melt viscosity. • Adding La{sub 2}O{sub 3} increases density.

Osseointegration properties of titanium dental implants modified with a nanostructured coating based on ordered porous silica and bioactive glass nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Covarrubias, Cristian, E-mail: ccovarrubias@odontologia.uchile.cl [Laboratory of Nanobiomaterials, Institute for Research in Dental Sciences, Faculty of Dentistry, University of Chile, Santiago (Chile); Mattmann, Matías [Laboratory of Nanobiomaterials, Institute for Research in Dental Sciences, Faculty of Dentistry, University of Chile, Santiago (Chile); Von Marttens, Alfredo [Department of Prosthesis, Faculty of Dentistry, University of Chile, Santiago (Chile); Caviedes, Pablo; Arriagada, Cristián [Laboratory of Cell Therapy, ICBM, Faculty of Medicine, University of Chile (Chile); Valenzuela, Francisco [Laboratory of Nanobiomaterials, Institute for Research in Dental Sciences, Faculty of Dentistry, University of Chile, Santiago (Chile); Rodríguez, Juan Pablo [Laboratory of Cell Biology, INTA, University of Chile, Santiago (Chile); Corral, Camila [Department of Restorative Dentistry, Faculty of Dentistry, University of Chile, Santiago (Chile)

2016-02-15

Graphical abstract: - Highlights: • The fabrication of a coating for osseointegration of titanium implant is presented. • The coating consists of nanoporous silica loaded with bioactive glass nanoparticles. • Coating accelerates the in vitro formation of apatite in simulated body fluid. • Coating promotes the osteogenic differentiation of stem cells. • Coating accelerates the formation of bone tissue in the periphery of the implant. - Abstract: The fabrication of a nanoporous silica coating loaded with bioactive glass nanoparticles (nBG/NSC) on titanium dental implant surface and its in vitro and in vivo evaluation is presented. The coating was produced by a combined sol–gel and evaporation induced self-assembly process. In vitro bioactivity was assessed in simulated body fluid (SBF) and investigating the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). A rat tibial model was employed to analyze the bone response to nBG/NSC-modified titanium implant surface in vivo. The nBG/NSC coating was confirmed at nano level to be constituted by a highly ordered nanoporous silica structure. The coating nanotopography in conjunction with the bioactivity of the BG particles accelerate the in vitro apatite formation and promote the osteogenic differentiation of hBMSCs in absence of osteogenic supplements. These properties accelerate the formation of bone tissue in the periphery of the implant after 3 weeks of implantation. Backscattered scanning electron microscopy images revealed the presence of gaps and soft tissue in the unmodified implant after 6 weeks, whereas the nBG/NSC-modified implant showed mature bone in intimate contact with the implant surface. The nBG/NSC coating appears promising for accelerating the osseointegration of dental implants.

Osseointegration properties of titanium dental implants modified with a nanostructured coating based on ordered porous silica and bioactive glass nanoparticles

International Nuclear Information System (INIS)

Covarrubias, Cristian; Mattmann, Matías; Von Marttens, Alfredo; Caviedes, Pablo; Arriagada, Cristián; Valenzuela, Francisco; Rodríguez, Juan Pablo; Corral, Camila

2016-01-01

Graphical abstract: - Highlights: • The fabrication of a coating for osseointegration of titanium implant is presented. • The coating consists of nanoporous silica loaded with bioactive glass nanoparticles. • Coating accelerates the in vitro formation of apatite in simulated body fluid. • Coating promotes the osteogenic differentiation of stem cells. • Coating accelerates the formation of bone tissue in the periphery of the implant. - Abstract: The fabrication of a nanoporous silica coating loaded with bioactive glass nanoparticles (nBG/NSC) on titanium dental implant surface and its in vitro and in vivo evaluation is presented. The coating was produced by a combined sol–gel and evaporation induced self-assembly process. In vitro bioactivity was assessed in simulated body fluid (SBF) and investigating the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). A rat tibial model was employed to analyze the bone response to nBG/NSC-modified titanium implant surface in vivo. The nBG/NSC coating was confirmed at nano level to be constituted by a highly ordered nanoporous silica structure. The coating nanotopography in conjunction with the bioactivity of the BG particles accelerate the in vitro apatite formation and promote the osteogenic differentiation of hBMSCs in absence of osteogenic supplements. These properties accelerate the formation of bone tissue in the periphery of the implant after 3 weeks of implantation. Backscattered scanning electron microscopy images revealed the presence of gaps and soft tissue in the unmodified implant after 6 weeks, whereas the nBG/NSC-modified implant showed mature bone in intimate contact with the implant surface. The nBG/NSC coating appears promising for accelerating the osseointegration of dental implants.

Properties of discontinuous S2-glass fiber-particulate-reinforced resin composites with two different fiber length distributions.

Science.gov (United States)

Huang, Qiting; Garoushi, Sufyan; Lin, Zhengmei; He, Jingwei; Qin, Wei; Liu, Fang; Vallittu, Pekka Kalevi; Lassila, Lippo Veli Juhana

2017-10-01

To investigate the reinforcing efficiency and light curing properties of discontinuous S2-glass fiber-particulate reinforced resin composite and to examine length distribution of discontinuous S2-glass fibers after a mixing process into resin composite. Experimental S2-glass fiber-particulate reinforced resin composites were prepared by mixing 10wt% of discontinuous S2-glass fibers, which had been manually cut into two different lengths (1.5 and 3.0mm), with various weight ratios of dimethacrylate based resin matrix and silaned BaAlSiO 2 filler particulates. The resin composite made with 25wt% of UDMA/SR833s resin system and 75wt% of silaned BaAlSiO 2 filler particulates was used as control composite which had similar composition as the commonly used resin composites. Flexural strength (FS), flexural modulus (FM) and work of fracture (WOF) were measured. Fractured specimens were observed by scanning electron microscopy. Double bond conversion (DC) and fiber length distribution were also studied. Reinforcement of resin composites with discontinuous S2-glass fibers can significantly increase the FS, FM and WOF of resin composites over the control. The fibers from the mixed resin composites showed great variation in final fiber length. The mean aspect ratio of experimental composites containing 62.5wt% of particulate fillers and 10wt% of 1.5 or 3.0mm cutting S2-glass fibers was 70 and 132, respectively. No difference was found in DC between resin composites containing S2-glass fibers with two different cutting lengths. Discontinuous S2-glass fibers can effectively reinforce the particulate-filled resin composite and thus may be potential to manufacture resin composites for high-stress bearing application. Copyright © 2017. Published by Elsevier Ltd.

Effects of composition on properties in an 11-component nuclear waste glass system

International Nuclear Information System (INIS)

Chick, L.A.; Piepel, G.F.; Mellinger, G.B.; May, R.P.; Gray, W.J.; Buckwalter, C.Q.

1981-09-01

Ninety simplified nuclear waste glass compositions within an 11-component oxide composition matrix were tested for crystallinity, viscosity, volatility, and chemical durability. Empirical models of property response as a function of glass composition were developed using statistical experimental design and modeling techniques. A new statistical technique was developed to calculate the effects of oxide components on each property. Independent melts were used to check the prediction accuracy of the models

Titanium minerals of placer deposits as a source for new materials

Science.gov (United States)

Kotova, Olga; Ponaryadov, Alexey

2015-04-01

obtained results of physical studies, mineral composition features, morphostructural characteristics and degree of alteration of titanium minerals from the placers specify a high potential of physical methods of processing (gravitational and magnetic separation, flotation) and possible application of combined methods of processing. Production of pigment titanium dioxide for further production of titanium white, paper, plastics etc is the usual application area of titanium concentrates. Titanium dioxide of high chemical purity is used to produce optically transparent glass, fiber optics, electronics (iPad), piezoceramics, in medical and food industry. We designed photocatalysts based on leucoxene from Pizhma placer. The results showed that the photocatalysts based on rutile, synthesized from leucoxene from Pizhma deposit, can be applied to decay phenols in water.

Microarc oxidized TiO2 based ceramic coatings combined with cefazolin sodium/chitosan composited drug film on porous titanium for biomedical applications.

Science.gov (United States)

Wei, Daqing; Zhou, Rui; cheng, Su; Feng, Wei; Li, Baoqiang; Wang, Yaming; Jia, Dechang; Zhou, Yu; Guo, Haifeng

2013-10-01

Porous titanium was prepared by pressureless sintering of titanium beads with diameters of 100, 200, 400 and 600 μm. The results indicated that the mechanical properties of porous titanium changed significantly with different bead diameters. Plastic deformations such as necking phenomenon and dimple structure were observed on the fracture surface of porous titanium sintered by beads with diameter of 100 μm. However, it was difficult to find this phenomenon on the porous titanium with a titanium bead diameter of 600 μm. The microarc oxidized coatings were deposited on its surface to improve the bioactivity of porous titanium. Furthermore, the cefazolin sodium/chitosan composited films were fabricated on the microarc oxidized coatings for overcoming the inflammation due to implantation, showing good slow-release ability by addition of chitosan. And the release kinetic process of cefazolin sodium in composited films could be possibly fitted by a polynomial model. Copyright © 2013 Elsevier B.V. All rights reserved.

Low temperature behaviour of elastomers in seals; Tieftemperaturverhalten von Elastomeren im Dichtungseinsatz

Energy Technology Data Exchange (ETDEWEB)

Jaunich, Matthias

2012-04-25

Elastomeric seals are of high importance as machine parts and construction elements, but in spite of this the low temperature limit for the use of a seal was not fully understood. Hence, the required safety relevant evaluation of the lowest acceptable operating seal temperature is difficult. Therefore the presented work was aimed to understand the temperature dependent material behaviour of representative elastomers and to conclude from this knowledge the low temperature limit down to which such seals could safely fulfil the desired requirements. Starting with the published statement that a seal can safely work below its glass transition temperature the influence of the glass-rubber-transition was investigated. At first the glass-rubber-transition temperatures of the selected elastomers were determined applying several techniques to allow a comparison with the behaviour of the seals during component tests. Furthermore a new method to characterise the low temperature behaviour of elastomers was developed that emulates the key features of the standardised compression set test used for seal materials. In comparison to the standardized test this new method allows a much faster measurement that can be automatically performed. Using a model based data analysis an extrapolation of the results to different temperatures can be performed and therefore the necessary measuring expenditure can be additionally reduced. For the temperature dependent characterisation of the failure process of real seals a measurement setup was designed and the materials behaviour was investigated. By use of the results of all applied characterisation techniques the observed dependence of the failure temperature on the degree of compression could be explained for the investigated seals under static load. Additionally information about the behaviour of such seals under dynamic load could be gained from the time dependent material behaviour by use of the time temperature superposition relationship

Effects of Polypropylene Orientation on Mechanical and Heat Seal Properties of Polymer-Aluminum-Polymer Composite Films for Pouch Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Fangxinyu Zeng

2018-01-01

Full Text Available In this study, polyamide-aluminum foil-polypropylene (PA-Al-PP composite films with different orientation status of the PP layer were prepared, and their morphology, tensile, peeling and heat seal behavior were studied. The comparative study of tensile and fracture behaviors of single-layer film of PA, Al and PP, as well as the composite films of PA-Al, PP-Al and PA-Al-PP revealed that in PA-Al-PP composite film, the PA layer with the highest tensile strength can share the tensile stress from the Al layer during stretching, while the PP layer with the lowest tensile strength can prevent further development of the small cracks on boundary of the Al layer during stretching. Moreover, the study of heat seal behavior suggested that both the orientation status and the heat seal conditions were important factors in determining the heat seal strength (HSS and failure behavior of the sample. Four failure types were observed, and a clear correspondence between HSS and failure types was found. The results also elucidated that for the composite film, only in the cases where the tensile stress was efficiently released by each layer during HSS measurement could the composite film exhibit desired high HSS that was even higher than its tensile strength.

Air-soil exchange of organochlorine pesticides in a sealed chamber.

Science.gov (United States)

Yang, Bing; Han, Baolu; Xue, Nandong; Zhou, Lingli; Li, Fasheng

2015-01-01

So far little is known about air-soil exchange under any sealed circumstances (e.g., in plastic and glass sheds), which however has huge implications for the soil-air-plant pathways of persistent organic pollutants including organochlorine pesticides (OCPs). A newly designed passive air sampler was tested in a sealed chamber for measuring the vertical concentration profiles of gaseous phase OCPs (hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs)). Air was sampled at 5, 15, and 30 cm above ground level every 10th day during a 60-day period by deploying polyurethane foam cylinders housed in acrylonitrile butadiene styrene-covered cartridges. Concentrations and compositions of OCPs along the vertical sections indicated a clear relationship with proximity to the mixture of HCHs and DDTs which escapes from the soils. In addition, significant positive correlations were found between air temperatures and concentrations of HCHs and DDTs. These results indicated revolatilization and re-deposition being at or close to dynamic pseudo-equilibrium with the overlying air. The sampler used for addressing air-soil exchange of persistent organic pollutants in any sealed conditions is discussed. Copyright © 2014. Published by Elsevier B.V.

Glass composition development for plasma processing of Hanford high sodium content low-level radioactive liquid waste

International Nuclear Information System (INIS)

Marra, J.C.

1995-02-01

To assess the acceptability of prospective compositions, response criteria based on durability, homogeneity, viscosity and volatility were defined. Response variables were weighted: durability 35%, homogeneity 25%, viscosity 25%, volatility 15%. A Plackett-Burman experimental design was used to define the first twelve glass formulations. Glass former additives included Al2O3, B2O3, CaO, Li2O, ZrO2 and SiO2. Lithia was added to facilitate fritting of the additives. The additives were normalized to silica content to ease experimental matrix definition and glass formulation. Preset high and low values of these ratios were determined for the initial twelve melts. Based on rankings of initial compositions, new formulations for testing were developed based on a simplex algorithm. Rating and ranking of subsequent compositions continued until no apparent improvement in glass quality was achieved in newly developed formulations. An optimized composition was determined by averaging the additive component values of the final best performing compositions. The glass former contents to form the optimized glass were: 16.1 wt % Al2O3, 12.3 wt % B2O3, 5.5 wt % CaO, 1.7 wt % Li2O, 3.3 wt % ZrO2, 61.1 wt % SiO2. An optimized composition resulted after only 25 trials despite studying six glass additives. A vitrification campaign was completed using a small-scale Joule heated melter. 80 lbs of glass was produced over 96 hours of continuous operation. Several salt compounds formed and deposited on melter components during the run and likely caused the failure of several pour chamber heaters. In an attempt to minimize sodium volatility, several low or no boron glasses were formulated. One composition containing no boron produced a homogeneous glass worthy of additional testing

Flexure and impact properties of glass fiber reinforced nylon 6-polypropylene composites

Science.gov (United States)

Kusaseh, N. M.; Nuruzzaman, D. M.; Ismail, N. M.; Hamedon, Z.; Azhari, A.; Iqbal, A. K. M. A.

2018-03-01

In recent years, polymer composites are rapidly developing and replacing the metals or alloys in numerous engineering applications. These polymer composites are the topic of interests in industrial applications such as automotive and aerospace industries. In the present research study, glass fiber (GF) reinforced nylon 6 (PA6)-polypropylene (PP) composite specimens were prepared successfully using injection molding process. Test specimens of five different compositions such as, 70%PA6+30%PP, 65%PA6+30%PP+5%GF, 60%PA6+30%PP+10%GF, 55%PA6+30%PP+15%GF and 50%PA6+30%PP+20%GF were prepared. In the experiments, flexure and impact tests were carried out. The obtained results revealed that flexure and impact properties of the polymer composites were significantly influenced by the glass fiber content. Results showed that flexural strength is low for pure polymer blend and flexural strength of GF reinforced composite increases gradually with the increase in glass fiber content. Test results also revealed that the impact strength of 70%PA6+30%PP is the highest and 55%PA6+30%PP+15%GF composite shows moderate impact strength. On the other hand, 50%PA6+30%PP+20%GF composite shows low toughness or reduced impact strength.

Flexural Progressive Failure of Carbon/Glass Interlayer and Intralayer Hybrid Composites.

Science.gov (United States)

Wang, Qingtao; Wu, Weili; Gong, Zhili; Li, Wei

2018-04-17

The flexural progressive failure modes of carbon fiber and glass fiber (C/G) interlayer and intralayer hybrid composites were investigated in this work. Results showed that the bending failure modes for interlayer hybrid composites are determined by the layup structure. Besides, the bending failure is characterized by the compression failure of the upper layer, when carbon fiber tends to distribute in the upper layer, the interlayer hybrid composite fails early, the failure force is characterized by a multi-stage slightly fluctuating decline and the fracture area exhibits a diamond shape. While carbon fiber distributes in the middle or bottom layer, the failure time starts late, and the failure process exhibits one stage sharp force/stress drop, the fracture zone of glass fiber above the carbon layers presents an inverted trapezoid shape, while the fracture of glass fiber below the carbon layers exhibits an inverted triangular shape. With regards to the intralayer hybrid composites, the C/G hybrid ratio plays a dominating role in the bending failure which could be considered as the mixed failures of four structures. The bending failure of intralayer hybrid composites occurs in advance since carbon fiber are located in each layer; the failure process shows a multi-stage fluctuating decline, and the decline slows down as carbon fiber content increases, and the fracture sound release has the characteristics of a low intensity and high frequency for a long time. By contrast, as glass fiber content increases, the bending failure of intralayer composites is featured with a multi-stage cliff decline with a high amplitude and low frequency for a short-time fracture sound release.

Effects of roughness on interfacial performances of silica glass and non-polar polyarylacetylene resin composites

International Nuclear Information System (INIS)

Jiang, Z.X.; Huang, Y.D.; Liu, L.; Long, J.

2007-01-01

The influence of roughness on interfacial performances of silica glass/polyarylacetylene resin composites was investigated. In order to obtain different roughness, silica glass surface was abraded by different grits of abrasives and its topography was observed by scanning electron microscopy and atomic force microscopy. At the same time, the failure mechanisms of composites were analyzed by fracture morphologies and the interfacial adhesion was evaluated by shear strength test. The results indicated that shear strength of silica glass/polyarylacetylene resin composites firstly increased and then decreased with the surface roughness of silica glass increased. The best surface roughness range of silica glass was 40-60 nm. The main mechanism for the improvement of the interfacial adhesion was physical interlocking at the interface

Effect of different glass and zeolite A compositions on the leach resistance of ceramic waste forms

International Nuclear Information System (INIS)

Lewis, M.A.; Hash, M.; Glandorf, D.

1996-01-01

A ceramic waste form is being developed for waste generated during electrometallurgical treatment of spent nuclear fuel. The waste is generated when fission products are removed from the electrolyte, LiCl-KCl eutectic. The waste form is a composite fabricated by hot isostatic pressing a mixture of glass frit and zeolite occluded with fission products and salt. Normalized release rate is less than 1 g/m 2 d for all elements in MCC-1 leach test run for 28 days in deionized water at 90 C. This leach resistance is comparable to that of early Savannah River glasses. We are investigating how leach resistance is affected by changes in cationic form of zeolite and in glass composition. Composites were made with 3 forms of zeolite A and 6 glasses. We used 3-day ASTM C1220-92 (formerly MCC-1) leach tests to screen samples for development purposes only. The leach test results show that the glass composites of zeolites 5A and 4A retain fission products equally well. Loss of Cs is small (0.1-0.5 wt%), while the loss of divalent and trivalent fission products is one or more orders of magnitude smaller. Composites of 5A retain chloride ion better in these short-term screens than 4A and 3A. The more leach resistant composites were made with durable glasses rich in silica and poor in alkaline earth oxides. XRD show that a salt phase was absent in the leach resistant composites of 5A and the better glasses but was present in the other composites with poorer leach performance. Thus, absence of salt phase corresponds to improved leach resistance. Interactions between zeolite and glass depend on composition of both

Characterization,Mechanical, and In Vitro Bioactivity Properties of Hydroxyapatite/Bioactive Glass Composite

Directory of Open Access Journals (Sweden)

Israa Kahatan Sabree

2016-12-01

Full Text Available Bioactive ceramic materials can help bone reparation and regeneration by offering support to bone growth. Biological hydroxyapatite powder was prepared by burning animal bone followed by studying the mechanical properties of hydroxyapatite (HA/ (20wt.%, and 40wt.% of binary bioactive glass (70% SiO2- 30% CaO in order to evaluate the influence of composition on the compressive strength and hardness. HA-composite material exhibited increasing density, microhardness, and compressive strength with increasing amount of glass addition. X-ray diffraction after sintering at 1200°C showed no alter of HA to secondary phases while the hydroxyapatite/ bioactive glass composites contained a HA phase and different amounts of wollastonite phase, depending on the amount of bioglass added. In vitro tests, the samples were soaked in simulated body fluid (SBF for ten days in order to evaluate the change in compression strength, weight loss, and pH. The HA composite reinforced with 40 wt % bioglass showed highest compression strength, and lowest weight loss

Characterisation of glass matrix composites reinforced with lead zirconate titanate particles

International Nuclear Information System (INIS)

Cannillo, Valeria; Manfredini, Tiziano; Montorsi, Monia; Tavoni, Francesca; Minay, Emma J.; Boccaccini, Aldo R.

2005-01-01

A new type of glass matrix composite reinforced with ferroelectric particulate secondary phase was investigated. Samples containing lead zirconate titanate (PZT) particles in a silicate lead glass were fabricated. Various sintering strategies were tested in order to optimise the processing route. The densest samples were obtained by hot-pressing. The composites were characterized by means of SEM observations, X-ray diffraction, differential thermal analysis and Vickers indentations. In order to get a deeper insight into the thermo-mechanical behaviour of the material, a FEM based numerical model was prepared and applied. In particular, the crack-particle interaction was assessed and thus possible toughening mechanisms were investigated. By means of the numerical modelling supported by SEM observations, traditional toughening mechanisms (e.g. crack deflection, particle debonding) were ruled out. Since the experimentally measured indentation fracture toughness of the composite is significantly higher than that of the unreinforced glass, the findings suggest that a new toughening mechanism may be active, based on the piezoelectric effect

Multifunctionality in epoxy/glass fibers composites with graphene interphase

OpenAIRE

Mahmood, Haroon

2017-01-01

In this project, the synergetic effect of a graphene interphase in epoxy/glass fibers composites was investigated by coating glass fibers (GF) with graphene oxide (GO) and reduced graphene oxide (rGO) nanosheets by an electrophoretic deposition (EPD) technique. Graphite oxide was prepared using modified Hummers method in which raw graphite powder was oxidized using potassium permanganate (KMnO4) in acidic solution. Using ultrasonic technique, the graphite oxide was dispersed homogenously in w...

TiO2 thin and thick films grown on Si/glass by sputtering of titanium targets in an RF inductively coupled plasma

International Nuclear Information System (INIS)

Valencia-Alvarado, R; López-Callejas, R; Mercado-Cabrera, A; Peña-Eguiluz, R; Muñoz-Castro, A E; Rodríguez-Méndez, B G; De la Piedad-Beneitez, A; De la Rosa-Vázquez, J M

2015-01-01

TiO 2 thin and thick films were deposited on silicon/glass substrates using RF inductive plasma in continuous wave. The films thickness, as well as phases control, is achieved with a gradual increase in temperature substrates varying supplied RF power or working gas pressure besides deposition time as well. The deposition conditions were: argon 80%/oxygen 20% carefully calibrated mixture of 2 to 7×10 −2 mbar as working gas pressure range. Deposition time 0.5 to 5 hours, 500 or 600 W RF power at 13.56 MHz frequency and 242-345 °C substrates temperature range. The titanium dioxide deposited on the substrates is grown by sputtering of a titanium target negatively polarized at 3-5 kV DC situated 14 mm in front of such substrates. The plasma reactor is a simple Pyrex-like glass cylindrical vessel of 50 cm long and 20 cm in diameter. Using the before describe plasma parameters we obtained films only anatase and both anatase/rutile phases with stoichiometric different. The films were characterized by X-ray photoelectron spectroscopy (XPS), stylus profilometer, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. (paper)

Thermal analysis and in vitro bioactivity of bioactive glass-alumina composites

Energy Technology Data Exchange (ETDEWEB)

Chatzistavrou, Xanthippi, E-mail: x.chatzistavrou@imperial.ac.uk [Solid State Physics Section, Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Kantiranis, Nikolaos, E-mail: kantira@geo.auth.gr [School of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Kontonasaki, Eleana, E-mail: kont@dent.auth.gr [School of Dentistry, Department of Fixed Prosthesis and Implant Prosthodontics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Chrissafis, Konstantinos, E-mail: hrisafis@physics.auth.gr [Solid State Physics Section, Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Papadopoulou, Labrini, E-mail: lambrini@geo.auth.gr [School of Geology, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Koidis, Petros, E-mail: pkoidis@dent.auth.gr [School of Dentistry, Department of Fixed Prosthesis and Implant Prosthodontics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Boccaccini, Aldo R., E-mail: a.boccaccini@imperial.ac.uk [Department of Materials, Faculty of Engineering, Imperial College, SW7 2AZ London (United Kingdom); Paraskevopoulos, Konstantinos M., E-mail: kpar@auth.gr [Solid State Physics Section, Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

2011-01-15

Bioactive glass-alumina composite (BA) pellets were fabricated in the range 95/5-60/40 wt.% respectively and were heat-treated under a specific thermal treatment up to 950 {sup o}C. Control (unheated) and heat-treated pellets were immersed in Simulated Body Fluid (SBF) for bioactivity testing. All pellets before and after immersion in SBF were studied by Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM-EDS) and X-ray Diffraction (XRD) analysis. All composite pellets presented bioactive response. On the surface of the heat-treated pellets the development of a rich biological hydroxyapatite (HAp) layer was delayed for one day, compared to the respective control pellets. Independent of the proportion of the two components, all composites of each group (control and heat-treated) presented the same bioactive response as a function of immersion time in SBF. It was found that by the applied methodology, Al{sub 2}O{sub 3} can be successfully applied in bioactive glass composites without obstructing their bioactive response. - Research Highlights: {yields} Isostatically pressed glass-alumina composites presented apatite-forming ability. {yields} The interaction with SBF resulted in an aluminium phosphate phase formation. {yields} The formation of an aluminium phosphate phase enhanced the in vitro apatite growth.

Carbon/PEEK composite materials as an alternative for stainless steel/titanium hip prosthesis: a finite element study.

Science.gov (United States)

Rezaei, Farshid; Hassani, Kamran; Solhjoei, Nosratollah; Karimi, Alireza

2015-12-01

Total hip replacement (THR) has been ranked within the most typical surgical processes in the world. The durability of the prosthesis and loosening of prosthesis are the main concerns that mostly reported after THR surgeries. In THR, the femoral prosthesis can be fixed by either cement or cementless methods in the patient's bones. In both procedures, the stability of the prosthesis in the hosted bone has a key asset in its long-term durability and performance. This study aimed to execute a comparative finite element simulation to assess the load transfer between the prosthesis, which is made of carbon/PEEK composite and stainless steel/titanium, and the femur bone. The mechanical behavior of the cortical bone was assumed as a linear transverse isotropic while the spongy bone was modeled like a linear isotropic material. The implants were made of stainless steel (316L) and titanium alloy as they are common materials for implants. The results showed that the carbon/PEEK composites provide a flatter load transfer from the upper body to the leg compared to the stainless steel/titanium prosthesis. Furthermore, the results showed that the von Mises stress, principal stress, and the strain in the carbon/PEEK composites prosthesis were significantly lower than that made of the stainless steel/titanium. The results also imply that the carbon/PEEK composites can be applied to introduce a new optimum design for femoral prosthesis with adjustable stiffness, which can decrease the stress shielding and interface stress. These findings will help clinicians and biomedical experts to increase their knowledge about the hip replacement.

Characterization of Glass Fibre – Coconut Coir– Human Hair Hybrid Composites

OpenAIRE

D. Senthilnathan; A Gnanavel Babu; G. B. Bhaskar; KGS. Gopinath

2014-01-01

A composite material is a combination of two or more materials arranged in the form of layer one on the other layer using binding material through some prescribed methods. In the Glass fibre coconut fibre human hair hybrid composite method, the epoxy resin is used as binding material, in which one layer is formed of glass fibre, followed by coconut fibre and then by human hair. By using hand layup method and by changing the above arrangement of layers, six types of laminates are prepared by u...

Sintered glass ceramic composites from vitrified municipal solid waste bottom ashes

International Nuclear Information System (INIS)

Aloisi, Mirko; Karamanov, Alexander; Taglieri, Giuliana; Ferrante, Fabiola; Pelino, Mario

2006-01-01

A glass ceramic composite was obtained by sinter-crystallisation of vitrified municipal solid waste bottom ashes with the addition of various percentages of alumina waste. The sintering was investigated by differential dilatometry and the crystallisation of the glass particles by differential thermal analysis. The crystalline phases produced by the thermal treatment were identified by X-ray diffraction analysis. The sintering process was found to be affected by the alumina addition and inhibited by the beginning of the crystal-phase precipitation. Scanning electron microscopy was performed on the fractured sintered samples to observe the effect of the sintering. Young's modulus and the mechanical strength of the sintered glass ceramic and composites were determined at different heating rates. The application of high heating rate and the addition of alumina powder improved the mechanical properties. Compared to the sintered glass ceramic without additives, the bending strength and the Young's modulus obtained at 20 deg. C/min, increased by about 20% and 30%, respectively

Composition of 12-18th century window glass in Belgium: Non-figurative windows in secular buildings and stained-glass windows in religious buildings

International Nuclear Information System (INIS)

Schalm, Olivier; Janssens, Koen; Wouters, Hilde; Caluwe, Danielle

2007-01-01

A set of ca. 500 window glass fragments originating from different historical sites in Belgium and covering the period 12 th -18 th century was analyzed by means of electron probe microanalysis. Most samples are archaeological finds deriving from non-figurative windows in secular buildings. However, the analyzed set also contains glass sampled from still existing non-figurative windows in secular buildings and stained-glass windows in religious buildings. A sudden compositional change at the end of the 14 th century can be noticed among the series of glass compositions that were obtained. These changes could be related to the use of different glassmaker recipes and to the introduction of new raw materials for glass making

Composition of 12-18 th century window glass in Belgium: Non-figurative windows in secular buildings and stained-glass windows in religious buildings

Science.gov (United States)

Schalm, Olivier; Janssens, Koen; Wouters, Hilde; Caluwé, Danielle

2007-07-01

A set of ca. 500 window glass fragments originating from different historical sites in Belgium and covering the period 12 th-18 th century was analyzed by means of electron probe microanalysis. Most samples are archaeological finds deriving from non-figurative windows in secular buildings. However, the analyzed set also contains glass sampled from still existing non-figurative windows in secular buildings and stained-glass windows in religious buildings. A sudden compositional change at the end of the 14 th century can be noticed among the series of glass compositions that were obtained. These changes could be related to the use of different glassmaker recipes and to the introduction of new raw materials for glass making.

Contrasted glass-whole rock compositions and phenocryst re-distribution, IPOD Sites 417 and 418

Science.gov (United States)

Staudigel, H.; Bryan, W. B.

1982-01-01

Major element composition ranges of closely associated basalt glass-whole rock pairs from individual small cooling units approach the total known range of basalt glass and whole rock compositions at IPOD sites 417 and 418. The whole rock samples fall into two groups: one is depleted in MgO and distinctly enriched in plagioclase but has lost some olivine and/or pyroxene relative to its corresponding glass; and the other is enriched in MgO and in phenocrysts of olivine and pyroxene as well as plagioclase compared to its corresponding glass. By analogy with observed phenocryst distributions in lava pillows, tubes, and dikes, and with some theoretical studies, we infer that bulk rock compositions are strongly affected by phenocryst redistribution due to gravity settling, flotation, and dynamic sorting after eruption, although specific models are not well constrained by the one-dimensional geometry of drill core. Compositional trends or groupings in whole rock data resulting from such late-stage processes should not be confused with more fundamental compositional effects produced in deep chambers or during partial melting.

Analysis of composition and microstructural uniformity of hybrid glass/carbon fibre composites

Energy Technology Data Exchange (ETDEWEB)

Beauson, J.; Markussen, C.M.; Madsen, Bo

2013-09-01

In hybrid fibre composites, the intermixing of the two types of fibres imposes challenges to obtain materials with a well-defined and uniform microstructure. In the present paper, the composition and the microstructural uniformity of hybrid glass/carbon fibre composites mixed at the fibre bundle level are investigated. The different levels of compositions in the composites are defined and experimentally determined. The composite volume fractions are determined using an image analysis based procedure. The global fibre volume fractions are determined using a gravimetrical based method. The local fibre volume fractions are determined using volumetric calculations. A model is presented to predict the interrelation of volume fractions in hybrid fibre composites. The microstructural uniformity of the composites is analysed by the determined variation in composite volume fractions. Two analytical methods, a standard deviation based method and a fast Fourier transform method, are used to quantify the difference in microstructural uniformity between composites, and to detect and quantify any repeating pattern in the composite microstructure. (Author)

Effect of Different Fillers on Adhesive Wear Properties of Glass Fiber Reinforced Polyester Composites

Directory of Open Access Journals (Sweden)

E. Feyzullahoğlu

2017-12-01

Full Text Available Polymeric composites are used for different aims as substitute of traditional materials such as metals; due to their improved strength at small specific weight. The fiber reinforced polymer (FRP composite material consists of polymeric matrix and reinforcing material. Polymeric materials are commonly reinforced with synthetic fibers such as glass and carbon. The glass fiber reinforced polyester (GFRP composites are used with different filler materials. The aim of this study is to investigate the effects of different filler materials on adhesive wear behavior of GFRP. In this experimental study; polymetilmetacrilat (PMMA, Glass beads (GB and Glass sand (GS were used as filling material in GFRP composite samples. The adhesive wear behaviors of samples were carried out using ball on disc type tribometer. The friction force and coefficient of friction were measured during the test. The volume loss and wear rate values of samples were calculated according to test results. Barcol hardness values of samples were measured. The densities of samples were measured. Results show that the wear resistance of GB filled GFRP composite samples was much more than non-filled and PMMA filled GFRP composite samples.

Technical Note: Updated durability/composition relationships for Hanford high-level waste glasses

International Nuclear Information System (INIS)

Piepel, G.F.; Hartley, S.A.; Redgate, P.E.

1996-03-01

This technical note presents empirical models developed in FYI 995 to predict durability as functions of glass composition. Models are presented for normalized releases of B, Li, Na, and Si from the 7-day Product Consistency Test (PCT) applied to quenched and canister centerline cooled (CCC) glasses as well as from the 28-day Materials Characterization Center-1 (MCC-1) test applied to quenched glasses. Models are presented for Composition Variation Study (CVS) data from low temperature melter (LTM) studies (Hrma, Piepel, et al. 1994) and high temperature melter (HTM) studies (Vienna et al. 1995). The data used for modeling in this technical note are listed in Appendix A

Development of the DWPF canister temporary shrink-fit seal

International Nuclear Information System (INIS)

Kelker, J.W. Jr.

1986-04-01

The Defense Waste Processing Facility is being constructed at The Savannah River Plant for the containerization of high-level nuclear waste in a wasteform for eventual permanent disposal. The waste will be incorporated in molten glass and solidified in type 304L stainless steel canisters, 2-feet in diameter x 9-feet 10-inches long, containing a flanged 6-in.-diam pipe fill-nozzle. The canisters have a minimum wall thickness of 3/8 in. Utilizing the heat from the glass filling operation, a shrink-fit seal for a plug in the end of the canister fill nozzle was developed that: will withstand the radioactive environment; will prevent the spread of contamination, and will keep moisture and water from entering the canister during storage and decontamination of the canister by wet-frit blasting to remove smearable and oxide-film fixed radioactive nuclides; is removable and can be replaced by a new oversize plug in the event the seal fails the pressure decay leakage test ( -4 atm cc/sec helium); will keep the final weld closure clean and free of nuclear contamination; will withstand being pressed into the nozzle without exposing external contamination or completely breaking the seal; is reliable; and is easily installed. The seal consists of: a removable sleeve (with a tapered bore) which is shrink-fitted into the nozzle bore during canister fabrication; and a tapered plug which is placed into the sleeved nozzle after the canister is filled with radioactive molten glass. A leak-tight shrink-fit seal is formed between the nozzle, sleeve, and plug upon temperature equilibrium. The temporarily sealed canister is transferred from the Melt cell to the Decon cell, and the surface is decontaminated. Next it is transferred to the Weld/Test cell where the temporary seal is pressed down into the nozzle, revealing a clean cavity where the canister final closure weld is made

Development of high strength hydroxyapatite for bone tissue regeneration using nanobioactive glass composites

Science.gov (United States)

Shrivastava, Pragya; Dalai, Sridhar; Sudera, Prerna; Sivam, Santosh Param; Vijayalakshmi, S.; Sharma, Pratibha

2013-02-01

With an increasing demand of biocompatible bone substitutes for the treatment of bone diseases and bone tissue regeneration, bioactive glass composites are being tested to improvise the osteoconductive as well as osteoinductive properties. Nanobioactive glass (nBG) composites, having composition of SiO2 70 mol%, CaO 26 mol % and P2O5 4 mol% were prepared by Freeze drying method using PEG-PPG-PEG co-polymer. Polymer addition improves the mechanical strength and porosity of the scaffold of nBG. Nano Bioactive glass composites upon implantation undergo specific reactions leading to the formation of crystalline hydroxyapatite (HA). This is tested in vitro using Simulated Body Fluid (SBF). This high strength hydroxyapatite (HA) layer acts as osteoconductive in cellular environment, by acting as mineral base of bones, onto which new bone cells proliferate leading to new bone formation. Strength of the nBG composites as well as HA is in the range of cortical and cancellous bone, thus proving significant for bone tissue regeneration substitutes.

Development of high strength hydroxyapatite for bone tissue regeneration using nanobioactive glass composites

International Nuclear Information System (INIS)

Shrivastava, Pragya; Dalai, Sridhar; Vijayalakshmi, S.; Sudera, Prerna; Sivam, Santosh Param; Sharma, Pratibha

2013-01-01

With an increasing demand of biocompatible bone substitutes for the treatment of bone diseases and bone tissue regeneration, bioactive glass composites are being tested to improvise the osteoconductive as well as osteoinductive properties. Nanobioactive glass (nBG) composites, having composition of SiO 2 70 mol%, CaO 26 mol % and P 2 O 5 4 mol% were prepared by Freeze drying method using PEG-PPG-PEG co-polymer. Polymer addition improves the mechanical strength and porosity of the scaffold of nBG. Nano Bioactive glass composites upon implantation undergo specific reactions leading to the formation of crystalline hydroxyapatite (HA). This is tested in vitro using Simulated Body Fluid (SBF). This high strength hydroxyapatite (HA) layer acts as osteoconductive in cellular environment, by acting as mineral base of bones, onto which new bone cells proliferate leading to new bone formation. Strength of the nBG composites as well as HA is in the range of cortical and cancellous bone, thus proving significant for bone tissue regeneration substitutes.

Investigation of polypyrrole/polyvinyl alcohol–titanium dioxide composite films for photo-catalytic applications

Energy Technology Data Exchange (ETDEWEB)

Cao, Shaoqiang; Zhang, Hongyang; Song, Yuanqing; Zhang, Jianling; Yang, Haigang; Jiang, Long, E-mail: jianglong@scu.edu.cn; Dan, Yi, E-mail: danyichenweiwei@163.com

2015-07-01

Graphical abstract: - Highlights: • The study provides an easy and convenient method to fabricate films, which will give guidance for the preparation of three-dimensional materials. • The PPy/PVA–TiO{sub 2} films can keep better photo-catalytic activities both under UV and visible light irradiation when compared with TiO{sub 2} film. • There exist electron transfers between PPy/PVA and TiO{sub 2}. - Abstract: Polypyrrole/polyvinyl alcohol–titanium dioxide (PPy/PVA–TiO{sub 2}) composite films used as photo-catalysts were fabricated by combining TiO{sub 2} sol with PPy/PVA solution in which PPy was synthesized by in situ polymerization of pyrrole (Py) in polyvinyl alcohol (PVA) matrix and loaded on glass. The prepared photo-catalysts were investigated by X-ray diffraction (XRD), ultraviolet–visible diffuse reflection spectroscopy (UV–vis DRS), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectra and photoluminescence (PL). The results indicate that the composites have same crystal structure as the TiO{sub 2} and extend the optic absorption from UV region to visible light region. By detecting the variation ratio, detected by ultraviolet–vis spectroscopy, of model pollutant rhodamine B (RhB) solution in the presence of the composite films under both UV and visible light irradiation, the photo-catalytic performance of the composite films was investigated. The results show that the PPy/PVA–TiO{sub 2} composite films show better photo-catalytic properties than TiO{sub 2} film both under UV and visible light irradiation, and the photo-catalytic degradation of RhB follows the first-order kinetics. The effects of the composition of composite films and the concentration of RhB on the photo-catalytic performance, as well as the possible photo-catalytic mechanism, were also discussed. By photo-catalytic recycle experiments, the structure stability of the PPy/PVA–TiO{sub 2} composite film was investigated and the results show that

Composition effects on chemical durability and viscosity of nuclear waste glasses - systematic studies and structural thermodynamic models

International Nuclear Information System (INIS)

Feng, X.

1988-01-01

Two of the primary criteria for the acceptability of nuclear waste glasses are their durability, i.e. chemical resistance to aqueous attack for 10 4 to 10 5 years, and processability, which requires their viscosity at the desired melt temperature to be sufficiently low. Chapter 3 presents the results of systematic composition variation studies around the preliminary reference glass composition WV205 and an atomistic interpretation of the effects of individual oxides. Chapter 4 is concerned with modifications of the Jantzen-Plodinec hydration model which takes into account formation of complex aluminosilicate compounds in the glass. Chapter 5 is devoted to the development and validation of the structural-thermodynamic model for both durability and viscosity. This model assumes the strength of bonds between atoms to be the controlling factor in the composition dependence of these glass properties. The binding strengths are derived from the known heats of formation and the structural roles of constituent oxides. Since the coordination state of various oxides in the glass is temperature dependent and cation size has opposite effects on the two properties, the correlation between melt viscosity and rate of corrosion at low temperature is not simply linear. Chapter 6 surveys the effects of aqueous phase composition on the leach behavior of glasses. These studies provide a comprehensive view of the effects of both glass composition and leachant composition on leaching. The models developed correlate both durability and viscosity with glass composition. A major implication is that these findings can be used in the systematic optimization of the properties of complex oxide glasses

Transition from glass to graphite in manufacture of composite aircraft structure

Science.gov (United States)

Buffum, H. E.; Thompson, V. S.

1978-01-01

The transition from fiberglass reinforced plastic composites to graphite reinforced plastic composites is described. Structural fiberglass design and manufacturing background are summarized. How this experience provides a technology base for moving into graphite composite secondary structure and then to composite primary structure is considered. The technical requirements that must be fulfilled in the transition from glass to graphite composite structure are also included.

Microstructure characteristic and excellent corrosion protection properties of sealed Zn-TiO{sub 2} composite coating for sintered NdFeB magnet

Energy Technology Data Exchange (ETDEWEB)

Yang Xiaokui [School of Materials Science and Engineering, Southwest University, Chongqing 400715 (China); Li Qing, E-mail: liqingd@swu.edu.c [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Zhang Shiyan; Liu Fang; Wang Shaoyin; Zhang Haixiao [School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China)

2010-04-09

In this paper, a protective sealed Zn-TiO{sub 2} composite coating (SCC) was prepared on sintered NdFeB magnet by electrodeposition and sol-gel combined technique. For a comparison, unsealed Zn-TiO{sub 2} composite coating (UCC) was also studied. The surface morphologies of composite coating were studied using scanning electron microscope (SEM). The microstructure of composite coatings and structure of sealing layer were studied by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectrum, respectively. The anticorrosive properties of composite coatings in neutral 3.5 wt.% NaCl solutions were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) technique. The results of corrosion tests showed that due to the blocking effect of sealing layer, SCC could suppress the corrosion process by holding back the transfer or diffusion of corrosive medium, and therefore showed the excellent corrosion protection properties for sintered NdFeB magnet.

The sealing of second mandibular temporary molar pits and fissure with the laser of Nd: YAG, phosphoric acid and the glass ionomer cement

International Nuclear Information System (INIS)

Toda, Maria Aparecida

2003-01-01

The main of our study was to check the sealing of second mandibular temporary molar pits and fissure, in vitro, with the laser of Nd: YAG, phosphoric acid at 37% and the glass ionomer cement (CIV, Fuji IX GC).The proposal was to check the structural morphologic changes in the laser irradiation upon the enamel surface to watch the pits and fissure sealing with the glass ionomer cement use after the laser irradiation and to verify the efficiency of the 'double conditioning' (phosphoric acid + Nd: YAG). At the same time we watch the evolution of the temperature in the pulp chamber's inside. Our desire was to achieve a therapeutic alternative technic to prevent the dental caries. The Nd: YAG laser parameters were the same: 79 mJ of energy per pulse; frequency of 5 Hz; mean power of 0,4 W; optical fiber on contact of 320 μm diameter; fluency of 99,52 J/ cm 2 , assuming that the only differential was the time of the laser application on the enamel surface. The samples were prepared with this way: Laser Nd: YAG (53 second) + acid + CIV (Fuji IX); Laser Nd: YAG (53 s); Laser Nd: YAG (20 s + 20 s) + acid + CIV; Laser Nd: YAG (20 s + 20 s); Acid + CIV; Control. Through the scanning electron microscopy (MEV) we noticed fusion and resolidification regions due to the laser irradiation and a better adaptation of the glass ionomer cement when we did the 'double conditioning'. Concerning the temperature increase we can conclude that the echeloned period was the best recommended because the temperature was found in a pattern that would not cause any damage to the dental pulp. For future studies we suggest a longer relaxing time between the laser irradiation, a comparative study of this method with other lasers, the use of other sealing materials and the study with the permanent teeth. (author)

Effect of Polymer Form and its Consolidation on Mechanical Properties and Quality of Glass/PBT Composites

Science.gov (United States)

Durai Prabhakaran, R. T.; Pillai, Saju; Charca, Samuel; Oshkovr, Simin Ataollahi; Knudsen, Hans; Andersen, Tom Løgstrup; Bech, Jakob Ilsted; Thomsen, Ole Thybo; Lilholt, Hans

2014-04-01

The aim of this study was to understand the role of the processing in determining the mechanical properties of glass fibre reinforced polybutylene terephthalate composites (Glass/PBT). Unidirectional (UD) composite laminates were manufactured by the vacuum consolidation technique using three different material systems included in this study; Glass/CBT (CBT160 powder based resin), Glass/PBT (prepreg tapes), and Glass/PBT (commingled yarns). The different types of thermoplastic polymer resin systems used for the manufacturing of the composite UD laminate dictate the differences in final mechanical properties which were evaluated by through compression, flexural and short beam transverse bending tests. Microscopy was used to evaluate the quality of the processed laminates, and fractography was used to characterize the observed failure modes. The study provides an improved understanding of the relationships between processing methods, resin characteristics, and mechanical performance of thermoplastic resin composite materials.

Study of the phase composition of nanostructures produced by the local anodic oxidation of titanium films

International Nuclear Information System (INIS)

Avilov, V. I.; Ageev, O. A.; Konoplev, B. G.; Smirnov, V. A.; Solodovnik, M. S.; Tsukanova, O. G.

2016-01-01

The results of experimental studies of the phase composition of oxide nanostructures formed by the local anodic oxidation of a titanium thin film are reported. The data of the phase analysis of titanium-oxide nanostructures are obtained by X-ray photoelectron spectroscopy in the ion profiling mode of measurements. It is established that the surface of titanium-oxide nanostructures 4.5 ± 0.2 nm in height possesses a binding energy of core levels characteristic of TiO_2 (458.4 eV). By analyzing the titanium-oxide nanostructures in depth by X-ray photoelectron spectroscopy, the formation of phases with binding energies of core levels characteristic of Ti_2O_3 (456.6 eV) and TiO (454.8 eV) is established. The results can be used in developing the technological processes of the formation of a future electronic-component base for nanoelectronics on the basis of titanium-oxide nanostructures and probe nanotechnologies.

In situ formation of titanium carbide using titanium and carbon-nanotube powders by laser cladding

International Nuclear Information System (INIS)

Savalani, M.M.; Ng, C.C.; Li, Q.H.; Man, H.C.

2012-01-01

Titanium metal matrix composite coatings are considered to be important candidates for high wear resistance applications. In this study, TiC reinforced Ti matrix composite layers were fabricated by laser cladding with 5, 10, 15 and 20 wt% carbon-nanotube. The effects of the carbon-nanotube content on phase composition, microstructure, micro-hardness and dry sliding wear resistance of the coating were studied. Microstructural observation using scanning electron microscopy showed that the coatings consisted of a matrix of alpha-titanium phases and the reinforcement phase of titanium carbide in the form of fine dendrites, indicating that titanium carbide was synthesized by the in situ reaction during laser irradiation. Additionally, measurements on the micro-hardness and dry sliding wear resistance of the coatings indicated that the mechanical properties were affected by the amount of carbon-nanotube in the starting precursor materials and were enhanced by increasing the carbon-nanotube content. Results indicated that the composite layers exhibit high hardness and excellent wear resistance.

In situ formation of titanium carbide using titanium and carbon-nanotube powders by laser cladding

Energy Technology Data Exchange (ETDEWEB)

Savalani, M.M., E-mail: mmfsmm@inet.polyu.edu.hk [Department of Industrial and Systems Engineering, Hong Kong Polytechnic University (Hong Kong); Ng, C.C.; Li, Q.H.; Man, H.C. [Department of Industrial and Systems Engineering, Hong Kong Polytechnic University (Hong Kong)

2012-01-15

Titanium metal matrix composite coatings are considered to be important candidates for high wear resistance applications. In this study, TiC reinforced Ti matrix composite layers were fabricated by laser cladding with 5, 10, 15 and 20 wt% carbon-nanotube. The effects of the carbon-nanotube content on phase composition, microstructure, micro-hardness and dry sliding wear resistance of the coating were studied. Microstructural observation using scanning electron microscopy showed that the coatings consisted of a matrix of alpha-titanium phases and the reinforcement phase of titanium carbide in the form of fine dendrites, indicating that titanium carbide was synthesized by the in situ reaction during laser irradiation. Additionally, measurements on the micro-hardness and dry sliding wear resistance of the coatings indicated that the mechanical properties were affected by the amount of carbon-nanotube in the starting precursor materials and were enhanced by increasing the carbon-nanotube content. Results indicated that the composite layers exhibit high hardness and excellent wear resistance.

The composition effect on the long-term corrosion of high-level waste glass

Energy Technology Data Exchange (ETDEWEB)

Hrma, P. [Pacific Northwest National Laboratory, Richland, Washington (United States)

1997-07-01

Waste glass can be optimized for long-term corrosion behavior if the key parameters that control the rate of corrosion are identified, measured, and modeled as functions of glass composition. Second-order polynomial models have been used to optimize glass with respect to a set of requirements on glass properties, such as viscosity and outcomes of standard corrosion tests. Extensive databases exist for the 7-day Product Consistency Test and the 28-day Materials Characterization Center tests, which have been used for nuclear waste glasses in the United States. Models based on these tests are reviewed and discussed to demonstrate the compositional effects on the extent of corrosion under specified conditions. However, modeling the rate of corrosion is potentially more useful for predicting long-term behavior than modeling the extent of corrosion measured by standard tests. Based on an experimental study of two glasses, it is shown that the rate of corrosion can be characterized by simple functions with physically meaningful coefficients. (author)

Non-classical homogeneous precipitation mediated by compositional fluctuations in titanium alloys

International Nuclear Information System (INIS)

Nag, S.; Zheng, Y.; Williams, R.E.A.; Devaraj, A.; Boyne, A.; Wang, Y.; Collins, P.C.; Viswanathan, G.B.; Tiley, J.S.; Muddle, B.C.; Banerjee, R.

2012-01-01

This paper presents experimental evidence of homogeneous precipitation of the α-phase within the β matrix of a titanium alloy, and then accounts for this phase transformation by a new, non-classical mechanism involving compositional fluctuations, based on the pseudo-spinodal concept [1]. This mechanism involves local compositional fluctuations of small amplitude which, when of a certain magnitude, can favor thermodynamically certain regions of the β matrix to transform congruently to the α-phase but with compositions far from equilibrium. Subsequently, as measured experimentally using the tomographical atom probe, continuous diffusional partitioning between the parent β- and product α-phases during isothermal annealing drives their compositions towards equilibrium. For a given alloy composition, the decomposition mechanism is strongly temperature dependent, which would be expected for homogeneous precipitation via the compositional fluctuation-mediated mechanism but not necessarily for one based on classical nucleation theory. The applicability of this mechanism to phase transformations in general is noted.

Flexural properties of polyethylene, glass and carbon fiber-reinforced resin composites for prosthetic frameworks.

Science.gov (United States)

Maruo, Yukinori; Nishigawa, Goro; Irie, Masao; Yoshihara, Kumiko; Minagi, Shogo

2015-01-01

High flexural properties are needed for fixed partial denture or implant prosthesis to resist susceptibility to failures caused by occlusal overload. The aim of this investigation was to clarify the effects of four different kinds of fibers on the flexural properties of fiber-reinforced composites. Polyethylene fiber, glass fiber and two types of carbon fibers were used for reinforcement. Seven groups of specimens, 2 × 2 × 25 mm, were prepared (n = 10 per group). Four groups of resin composite specimens were reinforced with polyethylene, glass or one type of carbon fiber. The remaining three groups served as controls, with each group comprising one brand of resin composite without any fiber. After 24-h water storage in 37°C distilled water, the flexural properties of each specimen were examined with static three-point flexural test at a crosshead speed of 0.5 mm/min. Compared to the control without any fiber, glass and carbon fibers significantly increased the flexural strength (p glass fiber (p glass fibers (p > 0.05). Fibers could, therefore, improve the flexural properties of resin composite and carbon fibers in longitudinal form yielded the better effects for reinforcement.

Glass fibres reinforced polyester composites degradation monitoring by surface analysis

Energy Technology Data Exchange (ETDEWEB)

Croitoru, Catalin [“Transilvania” University of Brasov, Materials Engineering and Welding Department, Eroilor 29 Str., 500036 Brasov (Romania); Patachia, Silvia, E-mail: st.patachia@unitbv.ro [“Transilvania” University of Brasov, Product Design Environment and Mechatronics Department, Eroilor 29 Str., 500036 Brasov (Romania); Papancea, Adina [“Transilvania” University of Brasov, Product Design Environment and Mechatronics Department, Eroilor 29 Str., 500036 Brasov (Romania); Baltes, Liana; Tierean, Mircea [“Transilvania” University of Brasov, Materials Engineering and Welding Department, Eroilor 29 Str., 500036 Brasov (Romania)

2015-12-15

Highlights: • Glass fibre-reinforced polyester composites surface analysis by photographic method. • The composites are submitted to accelerated ageing by UV irradiation at 254 nm. • The UV irradiation promotes differences in the surface chemistry of the composites. • MB dye is differently adsorbed on surfaces with different degradation degrees. • Good correlation between the colouring degree and surface chemistry. - Abstract: The paper presents a novel method for quantification of the modifications that occur on the surface of different types of gel-coated glass fibre-reinforced polyester composites under artificial UV-ageing at 254 nm. The method implies the adsorption of an ionic dye, namely methylene blue, on the UV-aged composite, and computing the CIELab colour space parameters from the photographic image of the coloured composite's surface. The method significantly enhances the colour differences between the irradiated composites and the reference, in contrast with the non-coloured ones. The colour modifications that occur represent a good indicative of the surface degradation, alteration of surface hydrophily and roughness of the composite and are in good correlation with the ATR-FTIR spectroscopy and optical microscopy results. The proposed method is easier, faster and cheaper than the traditional ones.

Modeling of laser welding of steel and titanium plates with a composite insert

Science.gov (United States)

Isaev, V. I.; Cherepanov, A. N.; Shapeev, V. P.

2017-10-01

A 3D model of laser welding proposed before by the authors was extended to the case of welding of metallic plates made of dissimilar materials with a composite multilayer intermediate insert. The model simulates heat transfer in the welded plates and takes into account phase transitions. It was proposed to select the composition of several metals and dimensions of the insert to avoid the formation of brittle intermetallic phases in the weld joint negatively affecting its strength properties. The model accounts for key physical phenomena occurring during the complex process of laser welding. It is capable to calculate temperature regimes at each point of the plates. The model can be used to select the welding parameters reducing the risk of formation of intermetallic plates. It can forecast the dimensions and crystalline structure of the solidified melt. Based on the proposed model a numerical algorithm was constructed. Simulations were carried out for the welding of titanium and steel plates with a composite insert comprising four different metals: copper and niobium (intermediate plates) with steel and titanium (outer plates). The insert is produced by explosion welding. Temperature fields and the processes of melting, evaporation, and solidification were studied.

Glass transition and composite formation in InF{sub 3}-containing oxyfluoroniobate system

Energy Technology Data Exchange (ETDEWEB)

Savchenko, N. N.; Ignatieva, L. N.; Marchenko, Yu. V. [Institute of Chemistry FEB RAS, Vladivostok (Russian Federation); Bouznik, V. M. [All-Russian Scientific Research Institute of Aviation Materials (Russian Federation)

2016-05-18

The glasses in the system MnNbOF{sub 5}-BaF{sub 2}-InF{sub 3} have been firstly synthesized and studied. The thermal parameters of these glasses are analyzed. It was stated that glass of the composition 40MnNbOF{sub 5}-40BaF{sub 2}-20InF{sub 3} is the most thermal stable in the system under study. By X-ray analysis the compositions of the crystalline phases obtained at the glass thermal treatment were determined: the main phases are Ba{sub 3}In{sub 2}F{sub 12} and BaNbOF{sub 5}. By Raman and IR spectra analysis it was stated that the networks of glasses in the system are built by the structural type of the glasses in NbO{sub 2}F-BaF{sub 2} system: (NbO{sub n}F{sub m}) polyhedra joined oxygen bridges. Indium trifluoride forms InF{sub 6} polyhedra, which are embeded between oxyfluoroniobate ions, forming a common networks or forms its own layers from InF{sub 6} polyhedra. IR-spectroscopy method showed that at devitrification of the sample 30MnNbOF{sub 5}-50BaF{sub 2}-20InF{sub 3} the band position and shape change in going from glass state to crystalline. The bands in the range 900–700 cm{sup −1} shift into the low-frequency range and transformed into narrow peaks characteristic for the crystalline state. It was determined that for this sample the IR-spectroscopy method fixes the presence of the crystalline phases at 340°C without time of exposure, despite the fact that X-ray analysis shows an amorphous state for this sample at the same temperature. It was suggested, that controlling the composition and conditions of annealing of the glasses it can be obtain the transparent glass-ceramics of definite composition.

Mechanical and thermal properties of water glass coated sisal fibre-reinforced polypropylene composite

CSIR Research Space (South Africa)

Phiri, G

2012-10-01

Full Text Available ?C). Figure 1 shows the processing steps followed to produce composite samples. Up to 15% fibre loading could be achieved and the sisal fibres were coated with water glass to improve fire resistance. In order to improve the adhesion between sisal... preparation process: (A) WG coated fibre, (B) High speed granulator, (C) Composite granules, (D) Single screw extruder, (E) Injection moulder and (F) Composite samples (dumbbells) Mechanical and thermal properties of water glass coated sisal fi bre...

Reverse engineering of mandible and prosthetic framework: Effect of titanium implants in conjunction with titanium milled full arch bridge prostheses on the biomechanics of the mandible.

Science.gov (United States)

De Santis, Roberto; Gloria, Antonio; Russo, Teresa; D'Amora, Ugo; Varriale, Angelo; Veltri, Mario; Balleri, Piero; Mollica, Francesco; Riccitiello, Francesco; Ambrosio, Luigi

2014-12-18

This study aimed at investigating the effects of titanium implants and different configurations of full-arch prostheses on the biomechanics of edentulous mandibles. Reverse engineered, composite, anisotropic, edentulous mandibles made of a poly(methylmethacrylate) core and a glass fibre reinforced outer shell were rapid prototyped and instrumented with strain gauges. Brånemark implants RP platforms in conjunction with titanium Procera one-piece or two-piece bridges were used to simulate oral rehabilitations. A lateral load through the gonion regions was used to test the biomechanical effects of the rehabilitations. In addition, strains due to misfit of the one-piece titanium bridge were compared to those produced by one-piece cast gold bridges. Milled titanium bridges had a better fit than cast gold bridges. The stress distribution in mandibular bone rehabilitated with a one-piece bridge was more perturbed than that observed with a two-piece bridge. In particular the former induced a stress concentration and stress shielding in the molar and symphysis regions, while for the latter design these stresses were strongly reduced. In conclusion, prosthetic frameworks changed the biomechanics of the mandible as a result of both their design and manufacturing technology. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ceramic fiber-reinforced monoclinic celsian phase glass-ceramic matrix composite material

Science.gov (United States)

Bansal, Narottam P. (Inventor); Dicarlo, James A. (Inventor)

1994-01-01

A hyridopolysilazane-derived ceramic fiber reinforced monoclinic celsian phase barium aluminum silicate glass-ceramic matrix composite material is prepared by ball-milling an aqueous slurry of BAS glass powder and fine monoclinic celsian seeds. The fibers improve the mechanical strength and fracture toughness and with the matrix provide superior dielectric properties.

Chemical composition analysis and product consistency tests to support enhanced Hanford waste glass models. Results for the third set of high alumina outer layer matrix glasses

Energy Technology Data Exchange (ETDEWEB)

Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States)

2015-12-01

In this report, the Savannah River National Laboratory provides chemical analyses and Product Consistency Test (PCT) results for 14 simulated high level waste glasses fabricated by the Pacific Northwest National Laboratory. The results of these analyses will be used as part of efforts to revise or extend the validation regions of the current Hanford Waste Treatment and Immobilization Plant glass property models to cover a broader span of waste compositions. The measured chemical composition data are reported and compared with the targeted values for each component for each glass. All of the measured sums of oxides for the study glasses fell within the interval of 96.9 to 100.8 wt %, indicating recovery of all components. Comparisons of the targeted and measured chemical compositions showed that the measured values for the glasses met the targeted concentrations within 10% for those components present at more than 5 wt %. The PCT results were normalized to both the targeted and measured compositions of the study glasses. Several of the glasses exhibited increases in normalized concentrations (NCi) after the canister centerline cooled (CCC) heat treatment. Five of the glasses, after the CCC heat treatment, had NC_B values that exceeded that of the Environmental Assessment (EA) benchmark glass. These results can be combined with additional characterization, including X-ray diffraction, to determine the cause of the higher release rates.

Composition models for the viscosity and chemical durability of West Valley related nuclear waste glasses

International Nuclear Information System (INIS)

Feng, X.; Saad, E.E.; Freeborn, W.P.; Macedo, P.B.; Pegg, I.L.; Sassoon, R.E.; Barkatt, A.; Finger, S.M.

1988-01-01

There are two important criteria that must be satisfied by a nuclear waste glass durability and processability. The chemical composition of the glass must be such that it does not dissolve or erode appreciably faster than the decay of the radioactive materials embedded in it. The second criterion, processability, means that the glass must melt with ease, must be easily pourable, and must not crystallize appreciably. This paper summarizes the development of simple models for predicting the durability and viscosity of nuclear waste glasses from their composition

Comparison of Mechanical Properties of Resin Composites with Resin Modified Glass Ionomers

Directory of Open Access Journals (Sweden)

Taha NA

2015-06-01

Full Text Available Statement of Problem: There are controversial reports regarding physical and mechanical properties of resin composites and glass ionomer cements. Some revealed higher strength and hardness for resin composites while others showed a comparable value for glass ionomer cements. Evaluation of mechanical properties of different types of resin composites in comparison with resin modified glass ionomers is not widely studied. Objectives: To measure and compare the flexural strength and Vickers hardness of three resin composites and two resins modified glass ionomer cements before and after ageing. Materials and Methods: Three resin composites, i.e. Filtek Supreme XTE (3M ESPE, Ice (SDI, Gradia (GC, and two resins modified glass ionomers, i.e. Fuji II LC (GC and Riva Light Cure (SDI, were selected. Ten barshaped specimens were prepared for each material and cured using LED curing light. After 24 hours storage in distilled water at 37oC, the specimens were randomly divided into two equal groups (n=5. The first group was tested as a baseline and the second group was restored at 37oC for another 29 days. Flexural strength was performed by four-point bending test using universal testing machine at crosshead speed of 0.5mm/min, and the maximum load at failure was recorded. The specimen’s halves were used for evaluating Vickers hardness, using a Digital Hardness Tester (300 g/15 sec and the Vickers hardness number (VHN was recorded. Data were analyzed using one-way analysis of variance (ANOVA, Tukey’s and student’s t-test. Results: After 24 hours of immersion, the highest hardness number was found for Filtek Supreme and Ice and the highest flexural strength was obtained for Gradia. After 30 days of storage, hardness of Fuji II LC and Gradia showed a significant decrease; flexural strength of Ice and Fuji II LC revealed a significant increase while Gradia and Filtek Supreme showed a significant decrease. Conclusions: Resin modified glass ionomers showed

Efficacy of Octacalcium Phosphate Collagen Composite for Titanium Dental Implants in Dogs

Directory of Open Access Journals (Sweden)

Tadashi Kawai

2018-02-01

Full Text Available Background: Previous studies showed that octacalcium (OCP collagen composite (OCP/Col can be used to repair human jaw bone defects without any associated abnormalities. The present study investigated whether OCP/Col could be applied to dental implant treatment using a dog tooth extraction socket model. Methods: The premolars of dogs were extracted; each extraction socket was extended, and titanium dental implants were placed in each socket. OCP/Col was inserted in the space around a titanium dental implant. Autologous bone was used to fill the other sockets, while the untreated socket (i.e., no bone substitute material served as a control. Three months after the operation, these specimens were analyzed for the osseointegration of each bone substitute material with the surface of the titanium dental implant. Results: In histomorphometric analyses, the peri-implant bone areas (BA% and bone-implant contact (BIC% were measured. There was no difference in BA% or BIC% between OCP/Col and autologous bone. Conclusion: These results suggested that OCP/Col could be used for implant treatment as a bone substitute.

Preparation and Dynamic Mechanical Properties at Elevated Temperatures of a Tungsten/Glass Composite

Science.gov (United States)

Gao, Chong; Wang, Yingchun; Ma, Xueya; Liu, Keyi; Wang, Yubing; Li, Shukui; Cheng, Xingwang

2018-03-01

Experiments were conducted to prepare a borosilicate glass matrix composite containing 50 vol.% tungsten and examine its dynamic compressive behavior at elevated temperatures in the range of 450-775 °C. The results show that the homogenous microstructure of the tungsten/glass composite with relative density of 97% can be obtained by hot-pressing sintering at 800 °C for 1 h under pressure of 30 MPa. Dynamic compressive testing was carried out by a separate Hopkinson pressure bar system with a synchronous device. The results show that the peak stress decreases and the composite transforms from brittle to ductile in nature with testing temperature increasing from 450 to 750 °C. The brittle-ductile transition temperature is about 500 °C. Over 775 °C, the composite loses load-bearing capacity totally because of the excessive softening of the glass phase. In addition, the deformation and failure mechanism were analyzed.

In Vitro Cytotoxicity Assessment of an Orthodontic Composite Containing Titanium-dioxide Nano-particles

OpenAIRE

Farzin Heravi; Mohammad Ramezani; Maryam Poosti; Mohsen Hosseini; Arezoo Shajiei; Farzaneh Ahrari

2013-01-01

Background and aims. Incorporation of nano-particles to orthodontic bonding systems has been considered to prevent enamel demineralization around appliances. This study investigated cytotoxicity of Transbond XT adhesive containing 1 wt% titanium dioxide (TiO2) nano-particles. Materials and methods. Ten composite disks were prepared from each of the conventional and TiO2-containg composites and aged for 1, 3, 5, 7 and 14 days in Dulbecco’s Modified Eagle’s Medium (DMEM). The extrac...

Structure of organometallic compounds obtained by plasma of titanium isopropoxide; Estructura de compuestos organometalicos obtenidos por plasma de isopropoxido de titanio

Energy Technology Data Exchange (ETDEWEB)

Arreola R, M. L.

2012-07-01

This work presents a study on the synthesis and characterization of organometallic compounds of titanium oxide obtained from glow discharges of titanium tetraisopropoxide (TTIP) and water on glass and polyethylene. The objective is the synthesis of titanium oxide particles which can be fixed on different supports for use in further studies of contaminants degradation in effluent streams. The synthesis was carried out by plasma in a glass tubular reactor of 750 cm{sup 3} and 15 cm length at 10{sup -1} mbar with power between 100 and 150 W during 2, 3 and 4 h. The precursors were TTIP and water vapor. TTIP is an organometallic compound composed of a central atom of Ti surrounded by 4 O atoms, which in turn are connected with chains of 3 C (propane s). The objective is the use of plasma collisions to separate the organic and inorganic phases of TTIP, so that both structure independently in a single material. The result was the formation of white titanium oxide powder composed with agglomerates of spherical particles with average diameter between 160 and 452 nm adhered to small films. The agglomerates have a tendency to change from film to particles with the energy applied to the synthesis. The study of the chemical structure showed a great presence of O{sub 2}-Ti-O{sub 2} (Ti surrounded by O) which can be found in most titanium oxides. Other chemical groups belonging to the organic phase were C=C=C, C=C=O and C{sub 2}-C-Ch appearing from the dehydrogenation of TTIP, which can be a possible precursor of this reactions kind. The structural superficial analyses showed that the atomic composition varies according to type of substrate used. The greatest content of Ti was obtained on glass substrates. However, the synthesis conditions had not evident effect in the participation of chemical states found in the inorganic phase. The crystalline studies indicated that the material is amorphous, although the de convoluted X-ray spectra showed that the synthesized titanium oxides

Bond strength of a composite resin to glass ionomer cements using different adhesive systems

Directory of Open Access Journals (Sweden)

Ana Carolina de Oliveira BECCI

2017-08-01

Full Text Available Abstract Introduction Glass ionomer cements are often used as a base or cavity lining prior to restorative material. Objective To evaluate the bond strength of a composite resin to different glass ionomer cements, when using a two-step conventional and self-etching adhesive systems. Material and method Three glass ionomer cements (Ketac Molar Easymix, Vitremer and Vitrebond, the composite resin Filtek Z350 XT and the adhesive systems Adper Single Bond 2, Clearfil SE Bond and Adper Easy One were used. As negative control, resin was bonded to cement without using an adhesive system. Holes (4 mm diameter, 2 mm deep prepared in acrilic bloks were filled with the glass ionomer cements (n=12/group. On the surface, an area of 1mm in diameter was delimited, the adhesive system was applied, and a specimen of composite resin with 1 mm height was made. After 24 hours storage (37 °C and 100% humidity, the microshear test was performed. Data were analyzed using two-way ANOVA and Tukey test for comparison between groups (α=0.05. Result The adhesive systems significantly improved the bond strenght of composite resin to glass ionomer cements (p≤0.001. There was no significant difference in bond strength when self-etching adhesive systems were compared with the simplified etch-and-rinse adhesive, except for Vitrebond where Clearfil SE Bond determined higher bond strength when compared to Adper Single Bond 2 (p=0.003. Conclusion Self-etching adhesive systems are a good option for establishing the bond between the composite resin and the glass ionomer cement.

Effect of Polymer Form and its Consolidation on Mechanical Properties and Quality of Glass/PBT Composites

DEFF Research Database (Denmark)

Raghavalu Thirumalai, Durai Prabhakaran; Pillai, Saju; Charca, Samuel

2014-01-01

different material systems included in this study; Glass/CBT (CBT160 powder based resin), Glass/PBT (prepreg tapes), and Glass/PBT (commingled yarns). The different types of thermoplastic polymer resin systems used for the manufacturing of the composite UD laminate dictate the differences in final......The aim of this study was to understand the role of the processing in determining the mechanical properties of glass fibre reinforced polybutylene terephthalate composites (Glass/PBT). Unidirectional (UD) composite laminates were manufactured by the vacuum consolidation technique using three...... mechanical properties which were evaluated by through compression, flexural and short beam transverse bending tests. Microscopy was used to evaluate the quality of the processed laminates, and fractography was used to characterize the observed failure modes. The study provides an improved understanding...

calcium sulphate hemihydrate and bioactive glass composites for ...

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 41; Issue 2. In vitro bioactivity evaluation of α -calcium sulphate hemihydrate and bioactive glass composites for their potential use in bone regeneration. YANYAN ZHENG CHENGDONG XIONG DUJUAN ZHANG LIFANG ZHANG. Volume 41 Issue 2 April 2018 Article ID ...

Immobilisation of radwastes in glass containers and products formed thereby

International Nuclear Information System (INIS)

Macedo, P.B.; Simmons, C.J.; Lagakos, N.; Simmons, J.H.; Tran, D.C.

1980-01-01

A method of preventing the dissemination of toxic material to the environment comprises forming an admixture of toxic material and glass packing in a hollow doped glass container of high silica content, or forming the admixture in a first container and then depositing at least a portion of the admixture in a hollow doped glass container of high silica content. The glass container is then heated to collapse its walls and to seal the container so that the toxic material is entrapped and sealed within the collapsed doped glass container. The thermal expansion coefficient of the container may be decreased prior to use by exchanging hydrogen ion in pores thereof with other cations followed by collapsing the pores. (author)

Enhanced mechanical properties of single walled carbon nanotube-borosilicate glass composite due to cushioning effect and localized plastic flow

Directory of Open Access Journals (Sweden)

Sujan Ghosh

2011-12-01

Full Text Available A borosilicate glass composite has been fabricated incorporating Single Wall Carbon Nanotubes (SWCNT in the glass matrix by melt-quench technique. Hardness and the fracture toughness of the composite, were found to increase moderately with respect to the base glass. Interestingly one can observe accumulation of SWCNT bundles around the crack zone though no such accumulation was observed in the crack free indentation zone. The enhanced hardness of the composite was discussed by correlating the cushioning as well as toughening behavior of the agglomerated SWCNT bundles. On the other hand enhanced plastic flow was proposed to be the prime reason for the accumulation of SWCNT bundles around the crack, which increases the toughness of the composite by reducing the crack length. Moreover to ascertain the enhanced plasticity of the composite than that of the glass we calculated the recovery resistance of glass and the composite where recovery resistance of composite was found to be higher than that of the glass.

Bond strength of resin cement to dentin and to surface-treated posts of titanium alloy, glass fiber, and zirconia

DEFF Research Database (Denmark)

Sahafi, Alireza; Peutzfeldt, Anne; Asmussen, Erik

2003-01-01

PURPOSE: To determine the effect of surface treatments on bond strength of two resin cements (ParaPost Cement and Panavia F) to posts of titanium alloy (ParaPost XH), glass fiber (ParaPost Fiber White), and zirconia (Cerapost), and to dentin. MATERIALS AND METHODS: After embedding, planar surfaces...... of posts (n = 9 to 14) and human dentin (n = 10) were obtained by grinding. The posts received one of three surface treatments: 1. roughening (sandblasting, hydrofluoric acid etching), 2. application of primer (Alloy Primer, Metalprimer II, silane), or 3. roughening followed by application of primer...

Corrosion behavior of a self-sealing pore micro-arc oxidation film on AM60 magnesium alloy

International Nuclear Information System (INIS)

Dong, Kaihui; Song, Yingwei; Shan, Dayong; Han, En-Hou

2015-01-01

Highlights: • Pore sealing constituents fall off and titanium oxides remain during corrosion. • Dark regions of film are corroded by migration of corrosion media through pores. • Light regions of film are corroded by transverse expansion of cracks. • Both outer and inner layers of the film provide effective protection to substrate. - Abstract: The deterioration process of a self-sealing pore micro-arc oxidation (MAO) film was investigated. The surface and cross-section corrosion morphologies were observed by scanning electron microscopy (SEM). Chemical composition was detected by EDS elemental mapping and XRD. The corrosion process was analyzed by electrochemical impedance spectroscopy (EIS). The surface of the film in dark and light regions exhibits different corrosion behavior. In the dark regions, the corrosion process mainly concentrates on the migration of corrosion media through the pores inward. In the light regions, the transverse expansion of cracks plays a key role, accompanying the exfoliation of film constituents.

Do Dental Resin Composites Accumulate More Oral Biofilms and Plaque than Amalgam and Glass Ionomer Materials?

Directory of Open Access Journals (Sweden)

Ning Zhang

2016-11-01

Full Text Available A long-time drawback of dental composites is that they accumulate more biofilms and plaques than amalgam and glass ionomer restorative materials. It would be highly desirable to develop a new composite with reduced biofilm growth, while avoiding the non-esthetics of amalgam and low strength of glass ionomer. The objectives of this study were to: (1 develop a protein-repellent composite with reduced biofilms matching amalgam and glass ionomer for the first time; and (2 investigate their protein adsorption, biofilms, and mechanical properties. Five materials were tested: A new composite containing 3% of protein-repellent 2-methacryloyloxyethyl phosphorylcholine (MPC; the composite with 0% MPC as control; commercial composite control; dental amalgam; resin-modified glass ionomer (RMGI. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate metabolic activity, colony-forming units (CFU, and lactic acid production. Composite with 3% MPC had flexural strength similar to those with 0% MPC and commercial composite control (p > 0.1, and much greater than RMGI (p < 0.05. Composite with 3% MPC had protein adsorption that was only 1/10 that of control composites (p < 0.05. Composite with 3% MPC had biofilm CFU and lactic acid much lower than control composites (p < 0.05. Biofilm growth, metabolic activity and lactic acid on the new composite with 3% MPC were reduced to the low level of amalgam and RMGI (p > 0.1. In conclusion, a new protein-repellent dental resin composite reduced oral biofilm growth and acid production to the low levels of non-esthetic amalgam and RMGI for the first time. The long-held conclusion that dental composites accumulate more biofilms than amalgam and glass ionomer is no longer true. The novel composite is promising to finally overcome the major biofilm-accumulation drawback of dental composites in order to reduce biofilm acids and secondary caries.

UV curing silicon-containing epoxy resin and its glass cloth reinforced composites

International Nuclear Information System (INIS)

Yang Guang; Tang Zhuo; Huang Pengcheng

2007-01-01

A UV-curable cationic silicon-containing epoxy resin formulation was developed. The gel conversion of the cured resin after 10-min UV irradiation reached 80% in the presence of 5% diaryliodonium salt photoinitiator and 5.5% polyol chain transfer agent by cationic ring-opening polymerization. The glass cloth-reinforced composites were fabricated with the silicon-containing epoxy resin using the wet lay-up technique and UV irradiation. The mechanical properties of the composites were evaluated. Compared with glass cloth reinforced bisphenol A epoxy resin matrix composites, the silicon-containing epoxy resin matrix composites possessed higher tensile strength and interlayer shear strength which was 158.5MPa and 9.9MPa respectively while other mechanical properties such as flexural property and tensile modulus were similar. (authors)

Approximal sealings on lesions in neighbouring teeth requiring operative treatment: an in vitro study.

Science.gov (United States)

Cartagena, Alvaro; Bakhshandeh, Azam; Ekstrand, Kim Rud

2018-02-07

With this in vitro study we aimed to assess the possibility of precise application of sealant on accessible artificial white spot lesions (WSL) on approximal surfaces next to a tooth surface under operative treatment. A secondary aim was to evaluate whether the use of magnifying glasses improved the application precision. Fifty-six extracted premolars were selected, approximal WSL lesions were created with 15% HCl gel and standardized photographs were taken. The premolars were mounted in plaster-models in contact with a neighbouring molar with Class II/I-II restoration (Sample 1) or approximal, cavitated dentin lesion (Sample 2). The restorations or the lesion were removed, and Clinpro Sealant was placed over the WSL. Magnifying glasses were used when sealing half the study material. The sealed premolar was removed from the plaster-model and photographed. Adobe Photoshop was used to measure the size of WSL and sealed area. The degree of match between the areas was determined in Photoshop. Interclass agreement for WSL, sealed, and matched areas were found as excellent (κ = 0.98-0.99). The sealant covered 48-100% of the WSL-area (median = 93%) in Sample 1 and 68-100% of the WSL-area (median = 95%) in Sample 2. No statistical differences were observed concerning uncovered proportions of the WSL-area between groups with and without using magnifying glasses (p values ≥ .19). However, overextended sealed areas were more pronounced when magnification was used (p = .01). The precision did not differ between the samples (p = .31). It was possible to seal accessible approximal lesions with high precision. Use of magnifying glasses did not improve the precision.

EFFECT OF SURFACE SEALING ON STAIN RESISTANCE OF A NANO-HYBRID RESIN COMPOSITE*

Directory of Open Access Journals (Sweden)

Günçe SAYGI

2015-04-01

Full Text Available Purpose: This study investigated the influence of sealant application on stain resistance of a nanohybrid resin composite compared to the efficacy of a bonding agent used as a surface sealant on prolonging color stability of the resin composite. Materials and Methods: 28 disc-shaped materials were prepared from a nano-hybrid resin composite Filtek Z550 and assigned to four groups: G1K: nonsealed; G2:Adper Single Bond; G3: Fortify ; G4: Biscover LV. After 24 h storage in distilled water at 37˚C, all specimens were subjected to thermocycling and immersed into coffee solution. Color measurements were performed using spectrophotometer (VITA Easyshade; Vident according to CIEL*a*b* system. Results: Color change values were significantly different among the groups in each evaluation period except for after thermocycling (p<0.05. For 7 days evaluation period, the difference between G3 and G4 group was statistically significant while G4 exhibited statistically significant differences (p<0.05 and p<0.0001 respectively compared to control (G1 in 14 day whereas no significant difference was found between GI and GII in 28-day evaluation period. However, ΔE values of sealed specimens (GIII, GIV differed significantly from non-sealed (GI specimens after 28 days of immersion in coffee solution (p<0.05 and p<0.0001 respectively. Conclusion: It may be concluded that using a bonding agent as a surface sealant does not increase stain resistance of resin composites of the sealants evaluated. Biscover LV showed the highest efficacy to prolong color stability of the resin composite.

The osteoinductive effect of chitosan-collagen composites around pure titanium implant surfaces in rats.

Science.gov (United States)

Kung, S; Devlin, H; Fu, E; Ho, K-Y; Liang, S-Y; Hsieh, Y-D

2011-02-01

The enhancing effects of chitosan on activation of platelets and differentiation of osteoprogenitor cells have been demonstrated in vitro. The purpose of this study was to evaluate the in vivo osteoinductive effect of chitosan-collagen composites around pure titanium implant surfaces. Chitosan-collagen composites containing chitosan of different molecular weights (450 and 750 kDa) were wrapped onto titanium implants and embedded into the subcutaneous area on the back of 15 Sprague-Dawley rats. The control consisted of implants wrapped with plain collagen type I membranes. Implants and surrounding tissues were retrieved 6 wks after surgery and identified by Alizarin red and Alcian blue whole mount staining. The newly formed structures in the test groups were further analyzed by Toluidine blue and Masson-Goldner trichrome staining, and immunohistochemical staining with osteopontin and alkaline phosphotase. The bone formation parameters of the new bone in the two test groups were measured and compared. New bone formed ectopically in both chitosan-collagen groups, whereas no bone induction occurred in the negative control group. These newly formed bone-like structures were further confirmed by immunohistochemical staining. Comparison of bone parameters of the newly induced bone revealed no statistically significant differences between the 450 and 750 kDa chitosan-collagen groups. Our results demonstrated that chitosan-collagen composites might induce in vivo new bone formation around pure titanium implant surfaces. Different molecular weights of chitosan did not show significantly different effects on the osteoinductive potential of the test materials. © 2010 John Wiley & Sons A/S.

Flexible, Heat-Resistant, and Flame-Retardant Glass Fiber Nonwoven/Glass Platelet Composite Separator for Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Ulrich Schadeck

2018-04-01

Full Text Available A new type of high-temperature stable and self-supporting composite separator for lithium-ion batteries was developed consisting of custom-made ultrathin micrometer-sized glass platelets embedded in a glass fiber nonwoven together with a water-based sodium alginate binder. The physical and electrochemical properties were investigated and compared to commercial polymer-based separators. Full-cell configuration cycling tests at different current rates were performed using graphite and lithium iron phosphate as electrode materials. The glass separator was high-temperature tested and showed a stability up to at least 600 °C without significant shrinking. Furthermore, it showed an exceptional wettability for non-aqueous electrolytes. The electrochemical performance was excellent compared to commercially available polymer-based separators. The results clearly show that glass platelets integrated into a glass fiber nonwoven performs remarkably well as a separator material in lithium-ion batteries and show high-temperature stability.

Enamels in stained glass windows: Preparation, chemical composition, microstructure and causes of deterioration

International Nuclear Information System (INIS)

Schalm, O.; Van der Linden, V.; Frederickx, P.; Luyten, S.; Van der Snickt, G.; Caen, J.; Schryvers, D.; Janssens, K.; Cornelis, E.; Van Dyck, D.; Schreiner, M.

2009-01-01

Stained glass windows incorporating dark blue and purple enamel paint layers are in some cases subject to severe degradation while others from the same period survived the ravages of time. A series of dark blue, green-blue and purple enamel glass paints from the same region (Northwestern Europe) and from the same period (16-early 20th centuries) has been studied by means of a combination of microscopic X-ray fluorescence analysis, electron probe micro analysis and transmission electron microscopy with the aim of better understanding the causes of the degradation. The chemical composition of the enamels diverges from the average chemical composition of window glass. Some of the compositions appear to be unstable, for example those with a high concentration of K 2 O and a low content of CaO and PbO. In other cases, the deterioration of the paint layers was caused by the less than optimal vitrification of the enamel during the firing process. Recipes and chemical compositions indicate that glassmakers of the 16-17th century had full control over the color of the enamel glass paints they made. They mainly used three types of coloring agents, based on Co (dark blue), Mn (purple) and Cu (light-blue or green-blue) as coloring elements. Blue-purple enamel paints were obtained by mixing two different coloring agents. The coloring agent for red-purple enamel, introduced during the 19th century, was colloidal gold embedded in grains of lead glass.

Plasma spraying of bioactive glass-ceramics containing bovine bone

Directory of Open Access Journals (Sweden)

Annamária Dobrádi

2017-06-01

Full Text Available Natural bone derived glass-ceramics are promising biomaterials for implants. However, due to their price and weak mechanical properties they are preferably applied as coatings on load bearing implants. This paper describes result obtained by plasma spraying of bioactive glass-ceramics containing natural bone onto selected implant materials, such as stainless steel, alumina, and titanium alloy. Adhesion of plasma sprayed coating was tested by computed X-ray tomography and SEM of cross sections. The results showed defect free interface between the coating and substrate, without cracks or gaps. Dissolution rate of the coating in simulated body fluid (SBF was readily controlled by the bone additives (phase composition, as well as microstructure. The SBF treatment of the plasma sprayed coating did not influence the boundary between the coating and substrate.

Preparation of SnO_2-Glass Composite Containing Cu Particles Reduced from Copper Ions in Glass Matrix : Effect of Glass Particle Size on Microstructure and Electrical Property

OpenAIRE

Haruhisa, SHIOMI; Kaori, UMEHARA; Faculty of Engineering and Design, Kyoto Institute of Technology; Faculty of Engineering and Design, Kyoto Institute of Technology

2000-01-01

An attempt was made to improve the electrical properties of SnO_2-glass composites by dispersing Cu particles with low resistivity and positive temperature coefficient of resistance(TCR)in the glass matrix. Cu metal particles were precipitated by reducing Cu_2O previously dissolved into the matrix glass by adding LaB_6 as a reducing agent. The effect of the glass particle size, which influences the homogeneity of LaB_6 dispersion in the powder mixture before firing, on the Cu precipitation in...

Post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin

International Nuclear Information System (INIS)

Yap, A.U.J.

1997-01-01

This study examined the post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin using a digital microhardness tester. Change in hardness of these materials over a period of 6 months was compared to that of conventional glass ionomer cements and a composite resin. With the exception of the composite resin, all materials showed a significant increase in hardness over 24 h after their initial set. Dual-cure resin-modified glass ionomer cements showed decreased hardness with increased storage time in saline at 37 o C. Results suggest that the addition of resins to glass ionomer cements does not improve initial hardness and does not negate the acid-base reaction of conventional cements. Resin addition may, however, lead to increased water sorption and decreased hardness. (author)

Tough and strong porous bioactive glass-PLA composites for structural bone repair.

Science.gov (United States)

Xiao, Wei; Zaeem, Mohsen Asle; Li, Guangda; Bal, B Sonny; Rahaman, Mohamed N

2017-08-01

Bioactive glass scaffolds have been used to heal small contained bone defects but their application to repairing structural bone is limited by concerns about their mechanical reliability. In the present study, the addition of an adherent polymer layer to the external surface of strong porous bioactive glass (13-93) scaffolds was investigated to improve their toughness. Finite element modeling (FEM) of the flexural mechanical response of beams composed of a porous glass and an adherent polymer layer predicted a reduction in the tensile stress in the glass with increasing thickness and elastic modulus of the polymer layer. Mechanical testing of composites with structures similar to the models, formed from 13-93 glass and polylactic acid (PLA), showed trends predicted by the FEM simulations but the observed effects were considerably more dramatic. A PLA layer of thickness -400 µm, equal to -12.5% of the scaffold thickness, increased the load-bearing capacity of the scaffold in four-point bending by ~50%. The work of fracture increased by more than 10,000%, resulting in a non-brittle mechanical response. These bioactive glass-PLA composites, combining bioactivity, high strength, high work of fracture and an internal architecture shown to be conducive to bone infiltration, could provide optimal implants for healing structural bone defects.

IMPACTS OF SMALL COLUMN ION EXCHANGE STREAMS ON DWPF GLASS FORMULATION: KT01, KT02, KT03, AND KT04-SERIES GLASS COMPOSITIONS

Energy Technology Data Exchange (ETDEWEB)

Fox, K.; Edwards, T.

2010-11-01

Four series of glass compositions were selected, fabricated, and characterized as part of a study to determine the impacts of the addition of Crystalline Silicotitanate (CST) and Monosodium Titanate (MST) from the Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) glass waste form and the applicability of the DWPF process control models. The KT01 and KT02-series of glasses were chosen to allow for the identification of the influence of the concentrations of major components of the glass on the retention of TiO{sub 2}. The KT03 series of glasses was chosen to allow for the identification of these influences when higher Nb{sub 2}O{sub 5} and ZrO{sub 2} concentrations are included along with TiO2. The KT04 series of glasses was chosen to investigate the properties and performance of glasses based on the best available projections of actual compositions to be processed at the DWPF (i.e., future sludge batches including the SCIX streams).

Interatomic potential to predict the favored and optimized compositions for ternary Cu-Zr-Hf metallic glasses

International Nuclear Information System (INIS)

Luo, S. Y.; Cui, Y. Y.; Dai, Y.; Li, J. H.; Liu, B. X.

2012-01-01

Under the framework of smoothed and long range second-moment approximation of tight-binding, a realistic interatomic potential was first constructed for the Cu-Zr-Hf ternary metal system. Applying the constructed potential, Monte Carlo simulations were carried out to compare the relative stability of crystalline solid solution versus its disordered counterpart over the entire composition triangle of the system (as a function of alloy composition). Simulations not only reveal that the origin of metallic glass formation but also determine, in the composition triangle, a quadrilateral region, within which metallic glass formation is energetically favored. It is proposed to define the energy differences between the crystalline solid solutions and disordered states as the driving force for amorphization and the corresponding calculations pinpoint an optimized composition locating at an composition of Cu 55 Zr 10 Hf 35 , around which the driving force for metallic glass formation reaches its maximum, suggesting that the ternary Cu-Zr-Hf metallic glasses designed to have the compositions around Cu 55 Zr 10 Hf 35 could be more stable than other alloys in the system. Moreover, for the Cu 55 Zr 10 Hf 35 metallic glass, the Voronoi tessellation calculations reveal some interesting features of its atomic configurations and coordination polyhedra distribution.

Synthesis of biodegradable polymer/glass fiber composite by EB irradiation and its biodegradability

International Nuclear Information System (INIS)

Yoshii, Fumio; Doam Thi The

2006-01-01

A composite was synthesized by irradiation of poly (butylene succinate), PBS and glass fiber (GF) in the presence of a polyfunctional monomer, trimethallyl isocyanurate (TMAIC), which accelerates gel formation of the matrix (PBS). The highest gel fraction was achieved at 1% concentration of TMAIC at the dose level of 200 kGy. Mechanical properties of the composites were highly dependent on the gel fraction of the polymer and volume fraction of glass fiber reinforcement in the composite. Optimal conditions to synthesize a PBS/GF composite reaching maximum value of bending strength were 1% TMAIC, 67% fiber volume fraction, and radiation dose of 200 kGy. These synthesized PBS/GF composites can be degraded by enzymes produced by the microorganism population in soil. (author)