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Sample records for glass fibre landfill

  1. Fibre glass induced synovitis.

    PubMed Central

    Cleland, L G; Vernon-Roberts, B; Smith, K

    1984-01-01

    Chronic synovitis developed in the dorsal extensor sheath of the hand of a 25-year-old manufacturer of fibre glass reinforced boats and surfboards . Particles found in synovial fluid aspirates were similar in morphology and elemental content to unused fibre glass and particles found in dust from the workshop floor. It was concluded that hard disc grinding required during manufacture resulted in percutaneous implantation of small glass particles, leading to chronic synovitis and effusion. Images PMID:6742919

  2. Fluoride Glass Fibres For Telecommunications

    NASA Astrophysics Data System (ADS)

    Maze, Gwenael; Cardin, Vincent; Poulain, Marcel

    1983-09-01

    Zirconium fluoride glasses are the best known and the most stable beryllium-free glasses. They offer numerous potential uses for I.R.-transmitting fibres and ultra-long repeaterless optical wave-guides. Various problems arise in the manufacturing of fluoride glass fibres, essentially because of the steep viscosity profile and the devitrification phenomena. This paper discusses the processes for manufacturing step-index preforms and for drawing fibres. Optical quality preforms have been obtained and fibres have been drawn over more than 1 km. A spectral loss measurement system has been constructed using fluoride glass optical components. Several curves showing the optical attenuation versus wavelength are presented and discussed. These fibres are now available for optical transmission in infra-red systems.

  3. Optical properties of microstructure tellurite glass fibres

    SciTech Connect

    Gaponov, D A; Biryukov, A S

    2006-04-30

    The dispersion characteristics and waveguide optical losses are calculated by the multipole method for microstructure optical fibres with a continuous core, which can be made of a tellurite glass holding much promise for fibre optics. The effect of geometrical parameters on the optical properties is studied and conditions for the single-mode propagation of radiation in such fibres are determined. (optical fibres and waveguides)

  4. Reactive fibre reinforced glass ionomer cements.

    PubMed

    Lohbauer, Ulrich; Walker, Jürgen; Nikolaenko, Sergej; Werner, Jan; Clare, Alexis; Petschelt, Anselm; Greil, Peter

    2003-08-01

    The mechanical properties of glass ionomer cements used in restorative dentistry reinforced by chopped glass fibres were investigated. Reactive glass fibres with a composition in the system SiO(2)-Al(2)O(3)-CaF(2)-Na(3)AlF(6) and a thickness of 26 microm were drawn by a bushing process. The manufacturing parameters were optimized with respect to maximum strength of the glass fibre reinforced ionomer cements. Powder to liquid ratio, pre-treatment of the glass, grain size distribution and fibre volume fraction were varied. Glass fibre and cement were characterized by X-ray diffraction, transmission electron microscopy and energy dispersive spectroscopy techniques, respectively. The highest flexural strength of the reinforced cement (15.6 MPa) was found by compounding 20 vol% reactive fibres and extending the initial dry gelation period up to 30 min. Microscopic examination of the fractured cements indicated a distinct reactive layer at the fibre surface. A pronounced fibre pull out mode gives rise to an additional work-of-fracture contributed by pulling the fibres out of the fracture surface.

  5. Glass fibre paper separator for electrochemical cells

    SciTech Connect

    Harris, F.J.T.

    1984-08-14

    A separator suitable for electrochemical cells of the lead-acid recombinant type comprises a sheet of entangled glass fibres. It has been found that significant improvements in performance can be obtained when 5 to 35% by weight of the fibres have a diameter of less than 1 ..mu..m. It has also been found surprisingly advantageous if the overall solubility of the glass fibres is greater than 3% and preferably at least 4%, by weight in 5 hours at 85/sup 0/ C. in sulphuric acid of specific gravity 1.200. It has been found that further benefits can accrue if all or a major proportion of the fibres cover a continuous range of fibre diameters and fibre lengths, and preferably a minor proportion of the fibres being over 5 mm in length.

  6. Soft glass photonic crystal fibres and their applications

    NASA Astrophysics Data System (ADS)

    Buczyński, Ryszard; Klimczak, Mariusz; Pysz, Dariusz; Stepniewski, Grzegorz; Siwicki, Bartłomiej; Cimek, Jarosław; Kujawa, Ireneusz; Piechal, Bernard; Stepień, Ryszard

    2015-05-01

    Most of the research work related to photonic crystal fibres has to date been focused on silica based fibres. Only in the recent years has there been a fraction of research devoted to fibres based on soft glasses, since some of them offer interesting properties as significantly higher nonlinearity than silica glass and wide transparency in the infrared range. On the other hand, attenuation in those glasses is usually one or more orders of magnitude higher that in silica glass, which limits their application area due to limited length of the fibres, which can be practically used. We report on the development of single-mode photonic crystal fibres made of highly nonlinear lead-bismuth-gallate glass with a zero dispersion wavelength at 1460 nm and flat anomalous dispersion. A two-octave spanning supercontinuum in the range 700-3000 nm was generated in 2 cm of the fibre. In contrast to the silica glass, various oxide based soft glasses with large refractive index difference can jointly undergo multiple thermal processing steps without degradation. The use of two soft glasses gives additional degrees of freedom in the design of photonic crystal fibres. As a result, highly nonlinear fibres with unique dispersion characteristics can be obtained. Soft glass allow also development of fibres with complex subwavelength refractive index distribution inside core of the fibre. A highly birefringent fibre with anisotropic core composed of subwavelength glass layers ordered in a rectangular structure was developed and is demonstrated

  7. Ytterbium fibre laser with a heavily Yb{sup 3+}-doped glass fibre core

    SciTech Connect

    Bufetov, Igor' A; Semenov, S L; Kosolapov, A F; Mel'kumov, Mikhail A; Dudin, V V; Dianov, Evgenii M; Galagan, B I; Denker, B I; Osiko, Vyacheslav V; Sverchkov, S E

    2006-03-31

    The use of optical fibres with a high concentration of active ions in the fibre core allows the reduction of the active fibre length and the increase in the threshold powers of various nonlinear effects in the fibre, thereby increasing the maximum output power of fibre lasers. For this purpose, we manufactured a highly concentrated ytterbium-doped ({approx}1.0x10{sup 21}cm{sup -3}) phosphate glass for the active fibre core and a pure glass of a similar composition for the fibre cladding. A single-mode fibre is fabricated from these glasses and generation is obtained in an ytterbium laser based on this fibre with the slope efficiency of no less than 60% at a wavelength of 975 nm. (letters)

  8. Modified glass fibre reinforced polymer composites

    NASA Astrophysics Data System (ADS)

    Cao, Yumei

    A high ratio of strength to density and relatively low-cost are some of the significant features of glass fibre reinforced polymer composites (GFRPCs) that made them one of the most rapidly developed materials in recent years. They are widely used as the material of construction in the areas of aerospace, marine and everyday life, such as airplane, helicopter, boat, canoe, fishing rod, racket, etc. Traditionally, researchers tried to raise the mechanical properties and keep a high strength/weight ratio using all or some of the following methods: increasing the volume fraction of the fibre; using different polymeric matrix material; or changing the curing conditions. In recent years, some new techniques and processing methods were developed to further improve the mechanical properties of glass fibre (GF) reinforced polymer composite. For example, by modifying the surface condition of the GF, both the interface strength between the GF and the polymer matrix and the shear strength of the final composite can be significantly increased. Also, by prestressing the fibre during the curing process of the composite, the tensile, flexural and the impact properties of the composite can be greatly improved. In this research project, a new method of preparing GFRPCs, which combined several traditional and modern techniques together, was developed. This new method includes modification of the surface of the GF with silica particles, application of different levels of prestressing on the GF during the curing process, and the change of the fibre volume fraction and curing conditions in different sets of experiments. The results of the new processing were tested by the three-point bend test, the short beam shear test and the impact test to determine the new set of properties so formed in the composite material. Scanning electronic microscopy (SEM) was used to study the fracture surface of the new materials after the mechanical tests were performed. By taking advantages of the

  9. Geoenvironmental weathering/deterioration of landfilled MSWI-BA glass.

    PubMed

    Wei, Yunmei; Saffarzadeh, Amirhomayoun; Shimaoka, Takayuki; Zhao, Chun; Peng, Xuya; Gao, Junmin

    2014-08-15

    Municipal solid waste incineration bottom ash (MSWI-BA) glass serves as a matrix of assorted bottom ash (BA) compounds. Deterioration of the BA glass phases is quite important as they regulate the distribution of a series of toxic elements. This paper studied landfilled MSWI-BA samples from the mineralogical and geochemical viewpoint to understand the deterioration behavior of the BA glass phases as well as mechanisms involved. Bulk analysis by PXRD as well as micro-scale analysis by optical microscopy and SEM/EDX was conducted for such purposes. The results revealed that dissolution of the BA glass phases has resulted in a deterioration layer of 10(0)-10(2)μm thickness after years of disposal. This rapid weathering process is highly relevant to the specific glass characteristics and solution pH. The BA glass phases with more embedded compounds and cracks/fissures tend to be more vulnerable. Moreover, the generally alkaline pH in ash deposit favors a rapid disruption of the glass phase. The weathering products are mainly gel phases (including Al-Si gel, Ca-Al-Si gel, Fe-Al-Si gel etc.) with iron oxide/hydroxide as accessory products. Breakdown of the BA glass phases triggers chemical evolution of the embedded compounds. Based on all the findings above, a model is proposed to illustrate a general evolution trend for the landfilled MSWI-BA glass phases.

  10. IR luminescence in bismuth-doped germanate glasses and fibres

    SciTech Connect

    Pynenkov, A A; Firstov, Sergei V; Panov, A A; Firstova, E G; Nishchev, K N; Bufetov, Igor' A; Dianov, Evgenii M

    2013-02-28

    We have studied the optical properties of lightly bismuth doped ({<=}0.002 mol %) germanate glasses prepared in an alumina crucible. The glasses are shown to contain bismuth-related active centres that have been identified previously only in bismuth-doped fibres produced by MCVD. With increasing bismuth concentration in the glasses, their luminescence spectra change markedly, which is attributable to interaction between individual bismuth centres. (optical fibres)

  11. Growth of Third-Harmonic Signal in Optical Glass Fibre

    DTIC Science & Technology

    1990-01-01

    harmonic signal In optical glass fibres , illuminated vith 10kV peak pover pulses from A NdYAG lasers has been observed. Broadband fluores.enc from the third...J’T. Al-0002 GROWTH OF THIFRO-HARMVONIC SIGNAL IN OPTICAL GLASS FIORE Irdexim tems 0,rkl f. N motwvij p~ .G For mo i fibres the Sit signal strtd g0r...Amorphous nature of glass ) but with time, as the fibre is illuminated with inltense laser light at 4 w1O6pm, the S1t signal 3rows. What is believed to

  12. Glass Fibre/Epoxy Resin Interface Life-Time Prediction.

    DTIC Science & Technology

    1983-04-01

    RD-Ai32 26 GLASS FIBRE /POXY RESIN INTERFACE LIFE-TIME PREDICTION 1/1 (U) BRISTOL UNIV (ENGLAND) H H WILLS PHYSICS LAB K H RSHBEE ET AL. APR 83...D 3005-MS GLASS FIBRE /EPOXY RESIN INTERFACE LIFE-TIME PREDICTION - Final Report by K H G Ashbee, Principal Investigator R Ho~l J P Sargent Elizabeth...REPORT h PERIOD COVERED. Glass Fibre /Epoxy Resin Interface Life-time F-inal Technical 11’ port PreictonApril 1981 - A:’ril 1983 6. PERFORMING ORG. REPORT

  13. Flexural properties of glass fibre reinforced acrylic resin polymers.

    PubMed

    Tacir, I H; Kama, J D; Zortuk, M; Eskimez, S

    2006-03-01

    In recent years, glass fibres have been used to strengthen denture base resins. A major difficulty in using reinforcing fibres with multiphase acrylic resins, such as powder liquid resins, is inadequate impregnation of the fibres with the resin. This investigation examined the reinforcing effect of glass fibres on the fracture resistance and flexural strength of acrylic denture base resins. Eighty identical specimens were formed in specially designed moulds in accordance with the manufacturer's recommendations. The four experimental groups were prepared and these consisted of conventional acrylic resin and the same resin reinforced with glass fibres. Ten specimens were fabricated in a standardized fashion for each experimental group. Flexural strength was tested using a 3-point universal testing machine. In this study, statistically significant differences were found in the flexural strength of the specimens (P < 0.05). The injection-moulded, fibre-reinforced group had significantly lower flexural strength than the injection-moulded group (P < 0.001), strength than the microwave-moulded, fibre-reinforced group (P < 0.001), and the microwave-moulded, fibre-reinforced group had lower flexural strength than the microwave-moulded group. The fracture resistance was significantly higher in the injection-moulded, fibre-reinforced group than in the injection-moulded group (P < 0.05), and the fracture resistance was significantly higher in the microwave-moulded, fibre-reinforced group than in the microwave-moulded group. Within the limitations of this study, the flexural strength of heat-polymerized PMMA denture resin was improved after reinforcement with glass fibres. It may be possible to apply these results to distal extension partial and complete denture bases.

  14. Yield strength of zirconia and glass fibre-reinforced posts.

    PubMed

    Pfeiffer, P; Schulz, A; Nergiz, I; Schmage, P

    2006-01-01

    The aim of this in vitro study was to evaluate the yield strengths of glass fibre-reinforced composite (FRC) posts and zirconia dioxide ceramic (ZDC) posts. Tapered glass FRC posts (DentinPost) and ZDC posts (Cerapost) of three sizes in diameter (ISO 50, 90, 110) were used for bending tests. Conventional prefabricated titanium posts of the same sizes served as control groups. The 0.2% yield strengths (R(0.2)) were tested on a universal testing machine. As zirconia posts fractured before they were yielded 0.2%, the fracture strength instead of the yield strength was recorded for these posts. One-way and two-way anova and Bonferroni-Dunn's multiple comparison tests were performed for the statistical analysis. The mean 0.2% yield strengths of the posts were 27 +/- 1 N for glass fibre-reinforced posts and 58 +/- 4 N for zirconia posts of ISO 50 (control group: 54 +/- 3 N). For ISO 90 yield strengths of 52 +/- 4 N for glass fibre-reinforced posts, 117 +/- 20 N for zirconia posts and 117 +/- 11 N for the control group were obtained. For ISO 110 mean yield strengths amounted to 73 +/- 5 N for glass fibre-reinforced posts, 166 +/- 23 N for zirconia posts and 141 +/- 12 N for the control group. Significantly higher yield strength was recorded for the zirconia and the titanium posts compared with the glass fibre-reinforced posts for the tested ISO sizes.

  15. Magnesium coated bioresorbable phosphate glass fibres: investigation of the interface between fibre and polyester matrices.

    PubMed

    Liu, Xiaoling; Grant, David M; Parsons, Andrew J; Harper, Lee T; Rudd, Chris D; Ahmed, Ifty

    2013-01-01

    Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg(2+) in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM). The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM) and X-ray diffraction (XRD) analysis, respectively. The roughness of the coatings was seen to increase from 40 ± 1 nm to 80 ± 1 nm. The mechanical properties (tensile strength and modulus) of fibre with coatings decreased with increased magnesium coating thickness.

  16. Magnesium Coated Bioresorbable Phosphate Glass Fibres: Investigation of the Interface between Fibre and Polyester Matrices

    PubMed Central

    Liu, Xiaoling; Grant, David M.; Parsons, Andrew J.; Harper, Lee T.; Rudd, Chris D.; Ahmed, Ifty

    2013-01-01

    Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg2+ in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM). The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM) and X-ray diffraction (XRD) analysis, respectively. The roughness of the coatings was seen to increase from 40 ± 1 nm to 80 ± 1 nm. The mechanical properties (tensile strength and modulus) of fibre with coatings decreased with increased magnesium coating thickness. PMID:24066297

  17. Numerical simulation of photonic-crystal tellurite-tungstate glass fibres used in parametric fibre devices

    SciTech Connect

    Sokolov, V O; Plotnichenko, V G; Nazaryants, V O; Dianov, Evgenii M

    2006-01-31

    Using the MIT Photonic-Bands Package to calculate fully vectorial definite-mode eigenmodes of Maxwell's equations with periodic boundary conditions in a plane-wave basis, light propagation is simulated in fibres formed by point defects in two-dimensional periodic lattices of cylindrical holes in a glass or of glass tubes. The holes and gaps between tubes are assumed filled with air. Single-site hexagonal and square lattices are considered, which were most often studied both theoretically and experimentally and are used to fabricate silica photonic-crystal fibres. As a defect, a single vacancy is studied - the absent lattice site (one hole in a glass or one of the tubes are filled with the same glass) and a similar vacancy with nearest neighbours representing holes of a larger diameter. The obtained solutions are analysed by the method of effective mode area. The dependences of the effective refractive index and dispersion of the fundamental mode on the geometrical parameters of a fibre are found. The calculations are performed for tellurite-tungstate 80TeO{sub 2}-20WO{sub 3} glass fibres taking into account the frequency dispersion of the refractive index. (optical fibres)

  18. Glass fibres: absence of pulmonary hazard in production workers

    PubMed Central

    Hill, J. W.; Whitehead, W. S.; Cameron, J. D.; Hedgecock, G. A.

    1973-01-01

    Hill, J. W., Whitehead, W. S., Cameron, J. D., and Hedgecock, G. A. (1973).British Journal of Industrial Medicine,30, 174-179. Glass fibres: absence of pulmonary hazard in production workers. Seventy fibreglass workers with a mean of 19·85 years in the industry are compared with a control group having no exposure to glass fibre but otherwise matched for age, sex, height, and weight, and residing in the same geographical area. Comparison was made by radiography, the administration of the modified Medical Research Council Short Questionnaire on Respiratory Symptoms (1960), amplified to include a detailed occupational history, and measurement of peak expiratory flow, FEV1, and FVC. Statistical analysis showed the control group to be at a slight disadvantage compared to the subject group in respect of complaints of phlegm and FVC. No evidence of any respiratory hazard due to glass fibre is shown. PMID:4703089

  19. Study of injection moulded long glass fibre-reinforced polypropylene and the effect on the fibre length and orientation distribution

    NASA Astrophysics Data System (ADS)

    Parveeen, B.; Caton-Rose, P.; Costa, F.; Jin, X.; Hine, P.

    2014-05-01

    Long glass fibre (LGF) composites are extensively used in manufacturing to produce components with enhanced mechanical properties. Long fibres with length 12 to 25mm are added to a thermoplastic matrix. However severe fibre breakage can occur in the injection moulding process resulting in shorter fibre length distribution (FLD). The majority of this breakage occurs due to the melt experiencing extreme shear stress during the preparation and injection stage. Care should be taken to ensure that the longer fibres make it through the injection moulding process without their length being significantly degraded. This study is based on commercial 12 mm long glass-fibre reinforced polypropylene (PP) and short glass fibre Nylon. Due to the semi-flexiable behaviour of long glass fibres, the fibre orientation distribution (FOD) will differ from the orientation distribution of short glass fibre in an injection molded part. In order to investigate the effect the change in fibre length has on the fibre orientation distribution or vice versa, FOD data was measured using the 2D section image analyser. The overall purpose of the research is to show how the orientation distribution chnages in an injection moulded centre gated disc and end gated plaque geometry and to compare this data against fibre orientation predictions obtained from Autodesk Moldflow Simulation Insight.

  20. Translucency of glass-fibre-reinforced composite materials.

    PubMed

    Nakamura, T; Tanaka, H; Kawamura, Y; Wakabayashi, K

    2004-08-01

    summary The purpose of this study was to examine the translucency of glass-fibre-reinforced composite framework materials. Vectris and FibreKor, as well as an experimental material, were the glass-fibre-reinforced framework materials used. Targis, Sculpture and Estenia were the types of particulate filler composites veneered onto frameworks. Specimens were fabricated from each material, 0.5 and 1.0 mm thick. In addition, laminate specimens, 1.5 mm thick, were fabricated. The translucency of each specimen was evaluated by determining its contrast ratio. The laminate specimens were examined for colour differences. The experimental framework material was more translucent than the enamel composite when it was not coloured, and was nearly as translucent as the dentine composite when coloured. The commercial tooth-coloured framework materials were nearly as translucent as the dentine composite. It was found that it was possible to reproduce the same colour as the veneering dentine composite, when the framework thickness was 0.5 mm, except in the case of FibreKor. Within the limitations of this study, tooth-coloured, glass-fibre-reinforced framework materials are nearly as translucent as the veneering dentine composite, but these materials affect the colour of the prosthesis if the thickness of the framework material is increased beyond a certain point. Copyright 2004 Blackwell Publishing Ltd.

  1. Photonic bandgap single-mode optical fibre with ytterbium-doped silica glass core

    SciTech Connect

    Egorova, O N; Semenov, S L; Vel'miskin, V V; Dianov, Evgenii M; Salganskii, M Yu; Yashkov, M V; Gur'yanov, Aleksei N

    2011-01-24

    A photonic bandgap fibre with an ytterbium-doped silica glass core is fabricated and investigated. The possibility of implementing single-mode operation of such fibres in a wide spectral range at a large (above 20 {mu}m) mode field diameter makes them promising for fibre lasers and amplifiers. To ensure a high quality of the beam emerging from the fibre, particular attention is paid to increasing the optical homogeneity of the ytterbium-doped core glass. (optical fibres)

  2. Comparison of effects on macrophage cultures of glass fibre, glass powder, and chrysotile asbestos

    PubMed Central

    Beck, E. G.; Holt, P. F.; Manojlović, N.

    1972-01-01

    Beck, E. G., Holt, P. F., and Manojlović, N. (1972).Brit. J. industr. Med.,29, 280-286. Comparison of effects on macrophage cultures of glass fibre, glass powder, and chrysotile asbestos. The effects on macrophage cultures of glass fibre, glass powder, and chrysotile asbestos are compared. Glass fibre behaves like chrysotile in producing an increase in cell membrane permeability in cultured macrophages. This is demonstrable by the increase in lactic dehydrogenase activity in the supernatant fluid. The metabolism, measured by lactate production, is not reduced as it is when quartz is phagocytosed. Glass powder behaves like the inert dust corundum, producing little change in the number of cells stained by erythrosin B and a small increase in lactate dehydrogenase activity, both being in the range of the control. There is an increase in lactate production as a result of higher metabolism due to phagocytosis. Dusts may produce two basic effects, namely a toxic effect and change in cell membrane permeability. A non-specific effect on the cell membrane due to the slow and sometimes incomplete process of ingestion of long fibres is probably a function of the morphology, particularly the length of the fibres. A primary specific effect induced by some dusts immediately follows contact with the cell membrane. Images PMID:4339803

  3. Comparison of effects of glass fibre and glass powder on guinea-pig lungs

    PubMed Central

    Botham, Susan K.; Holt, P. F.

    1973-01-01

    Botham, Susan K., and Holt, P. F. (1973).British Journal of Industrial Medicine,30, 232-236. Comparison of effects of glass fibre and glass powder on guinea-pig lungs. Following 24 hours inhalation by guinea-pigs of powdered glass dust, the pulmonary effects over the succeeding month differed from those previously observed to follow inhalation of glass fibre in that (1) fewer erythrocytes escaped from the capillaries, (2) very few giant cells were produced, (3) erythrocytes and intracellular glass particles were cleared more readily because junctions between respiratory and terminal bronchioles were not blocked by giant cells, (4) intracellular granules containing Perls-positive material did not appreciably increase in number or intensity of staining during the month, and (5) particles were not coated with Perls-positive material during the time that pseudo-asbestos bodies would be formed from glass fibres. The difference between the effects of chemically similar glass powder and fibre during a month in a guinea-pig lung is considered to be due to the morphology of the inhaled particle. Images PMID:4124978

  4. Landfills

    EPA Pesticide Factsheets

    To provide information on landfills, including laws/regulations, and technical guidance on municipal solid waste, hazardous waste, industrial, PCBs, and construction and debris landfills. To provide resources for owners and operators of landfills.

  5. Multilayered Glass Fibre-reinforced Composites In Rotational Moulding

    NASA Astrophysics Data System (ADS)

    Chang, W. C.; Harkin-Jones, E.; Kearns, M.; McCourt, M.

    2011-05-01

    The potential of multiple layer fibre-reinforced mouldings is of growing interest to the rotational moulding industry because of their cost/performance ratio. The particular problem that arises when using reinforcements in this process relate to the fact that the process is low shear and good mixing of resin and reinforcement is not optimum under those conditions. There is also a problem of the larger/heavier reinforcing agents segregating out of the powder to lay up on the inner part surface. In this study, short glass fibres were incorporated and distributed into a polymer matrix to produce fibre-reinforced polymer composites using the rotational moulding process and characterised in terms of morphology and mechanical properties.

  6. Multilayered Glass Fibre-reinforced Composites In Rotational Moulding

    SciTech Connect

    Chang, W. C.; Harkin-Jones, E.; Kearns, M.; McCourt, M.

    2011-05-04

    The potential of multiple layer fibre-reinforced mouldings is of growing interest to the rotational moulding industry because of their cost/performance ratio. The particular problem that arises when using reinforcements in this process relate to the fact that the process is low shear and good mixing of resin and reinforcement is not optimum under those conditions. There is also a problem of the larger/heavier reinforcing agents segregating out of the powder to lay up on the inner part surface. In this study, short glass fibres were incorporated and distributed into a polymer matrix to produce fibre-reinforced polymer composites using the rotational moulding process and characterised in terms of morphology and mechanical properties.

  7. Mortality experience of glass fibre workers.

    PubMed Central

    Shannon, H S; Hayes, M; Julian, J A; Muir, D C

    1984-01-01

    A historical prospective mortality study was conducted at an insulating wool plant in Ontario, Canada, on 2576 men who had worked for at least 90 days and were employed between 1955 and 1977. Eighty eight deaths were found in the 97.2% of men traced. Mortality was compared by the person-years method with that of the Ontario population. Measurements taken since 1977 show very low fibre concentrations. The overall standardised mortality ratio (SMR) was 78%, significantly below 100. Among plant only employees, seven deaths were attributed to lung cancer compared with 4.22 expected, a non-significant excess (SMR = 166; 95% confidence limits 67 to 342). No confirmed cases of mesothelioma were observed and no other disease was significantly increased in plant workers. PMID:6691934

  8. Multimode supercontinuum generation in chalcogenide glass fibres.

    PubMed

    Kubat, Irnis; Bang, Ole

    2016-02-08

    Mid-infrared supercontinuum generation is considered in chalcogenide fibres when taking into account both polarisations and the necessary higher order modes. In particular we focus on high pulse energy supercontinuum generation with long pump pulses. The modeling indicates that when only a single polarisation in the fundamental mode is considered the obtainable supercontinuum bandwidth is substantially exaggerated compared to when both polarisations are taken into account. Our modeling shows that if the pump pulse is short enough (≤ 10 ps) then higher order modes are not important because of temporal walk-off. In contrast long pump pulses (≥ 40 ps) will efficiently excite higher order modes through Raman scattering, which will deplete the fundamental mode of energy and limit the possibility of obtaining a broadband supercontinuum.

  9. Low Temperature Thermal Conductivity of Woven Fabric Glass Fibre Composites

    NASA Astrophysics Data System (ADS)

    Kanagaraj, S.; Pattanayak, S.

    2004-06-01

    Fibre reinforced composites are replacing conventional materials due to its compatible and superior properties at low temperatures. Transverse thermal conductivity of plain fabric E-glass/Epoxy composites with the fibre concentrations of 32.5%, 35.2%, 39.2% and 48.9% has been studied in a GM-refrigerator based experimental setup using guarded hotplate technique. Experiments are carried out with the sets of stability criteria. This paper presents the investigation of the influence of the fibre concentration and temperature on the thermal conductivity of fabric composites from 30 K to 300K. It is observed from the experimental results that thermal conductivity increases with the increase of temperature and also with fibre concentration with different rate in different temperature range. The series model has been used to predict the thermal conductivity and compared with the experimental results. It is observed that below the crossover temperature of the composites, which varies from 150-225K depending upon their fibre concentration, the experimental results are within 10% with that of predicted values. The possible causes of variation are analyzed. The physical phenomenon behind the temperature dependence of thermal conductivity is discussed in detail.

  10. Low Temperature Thermal Conductivity of Woven Fabric Glass Fibre Composites

    SciTech Connect

    Kanagaraj, S.; Pattanayak, S.

    2004-06-28

    Fibre reinforced composites are replacing conventional materials due to its compatible and superior properties at low temperatures. Transverse thermal conductivity of plain fabric E-glass/Epoxy composites with the fibre concentrations of 32.5%, 35.2%, 39.2% and 48.9% has been studied in a GM-refrigerator based experimental setup using guarded hotplate technique. Experiments are carried out with the sets of stability criteria. This paper presents the investigation of the influence of the fibre concentration and temperature on the thermal conductivity of fabric composites from 30 K to 300K. It is observed from the experimental results that thermal conductivity increases with the increase of temperature and also with fibre concentration with different rate in different temperature range. The series model has been used to predict the thermal conductivity and compared with the experimental results. It is observed that below the crossover temperature of the composites, which varies from 150-225K depending upon their fibre concentration, the experimental results are within 10% with that of predicted values. The possible causes of variation are analyzed. The physical phenomenon behind the temperature dependence of thermal conductivity is discussed in detail.

  11. Tensile properties of glass/natural jute fibre-reinforced polymer bars for concrete reinforcement

    NASA Astrophysics Data System (ADS)

    Han, J. W.; Lee, S. K.; Kim, K. W.; Park, C. G.

    2015-12-01

    The tensile performance of glass/natural jute fibre-reinforced polymer (FRP) bar, intended for concrete reinforcement was evaluated as a function of volume fraction of natural jute fibre. Natural jute fibre, mixed at a ratio of 7:3 with vinyl ester, was surface-treated with a silane coupling agent and used to replaced glass fibre in the composite in volume fractions of 0%, 30%, 50%, 70%, and 100%. The tensile load-displacement curve showed nearly linear elastic behaviour up to 50% natural jute fibre, but was partially nonlinear at a proportion of 70%. However, the glass/natural jute FRP bars prepared using 100% natural jute fibre showed linear elastic behaviour. Tensile strength decreased as the natural jute fibre volume fraction increased because the tensile strength of natural jute fibre is much lower than that of glass fibre (about 1:8.65). The degree of reduction was not proportional to the natural jute fibre volume fraction due to the low density of natural jute fibre (1/2 that of glass fibre). Thus, as the mix proportion of natural jute fibre increased, the amount (wt%) and number of fibres used also increased.

  12. Mechanical Property Analysis on Sandwich Structured Hybrid Composite Made from Natural Fibre, Glass Fibre and Ceramic Fibre Wool Reinforced with Epoxy Resin

    NASA Astrophysics Data System (ADS)

    Bharat, K. R.; Abhishek, S.; Palanikumar, K.

    2017-06-01

    Natural fibre composites find wide range of applications and usage in the automobile and manufacturing industries. They find lack in desired properties, which are required for present applications. In current scenario, many developments in composite materials involve the synthesis of Hybrid composite materials to overcome some of the lacking properties. In this present investigation, two sandwich structured hybrid composite materials have been made by reinforcing Aloe Vera-Ceramic Fibre Wool-Glass fibre with Epoxy resin matrix and Sisal fibre-Ceramic Fibre Wool-Glass fibre with Epoxy resin matrix and its mechanical properties such as Tensile, Flexural and Impact are tested and analyzed. The test results from the two samples are compared and the results show that sisal fibre reinforced hybrid composite has better mechanical properties than aloe vera reinforced hybrid composite.

  13. Glass fibre reinforced acrylic resin complete dentures: a 5-year clinical study.

    PubMed

    Goguţă, Luciana Maria; Bratu, Dorin; Jivănescu, Anca; Erimescu, Raluca; Mărcăuţeanu, Corina

    2012-03-01

    The aim of the study was to establish the wear resistance of the glass fiber reinforced complete dentures comparative to the traditional acrylic complete dentures. Complete new dentures were made to replace old fractured 'un'-reinforced acrylic dentures. The total number of dentures was 30 and woven E-glass fibre reinforcements were used in maxillary complete dentures. Unidirectional E-glass fibre reinforcements were used as partial fibre reinforcements in mandibular complete dentures. Ten complete acrylic un-reinforced dentures were used as control. The follow-up period was 5 years and the recalls were made at 6 months. After 5 years of wearing the new dentures, the control dentures suffered seven fractures. After 5 years all the mandibular reinforced dentures were in good shape. The maxillary complete reinforced dentures suffered four partial fractures. Fracture lines were restricted by the glass fibre net and the patients could still use their dentures. Pre-impregnated E-glass fibre nets and polymer pre-impregnated E-glass unidirectional fibres are useful in reinforcing acrylic resin complete dentures especially were heavy occlusal forces are involved. Glass fibre reinforcement will be applied on the tension side in both cases (total fibre reinforcement and partial fibre reinforcement). The reinforcement cannot replace the necessary linings and occlusal adjustments. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

  14. Composites for bone repair: phosphate glass fibre reinforced PLA with varying fibre architecture.

    PubMed

    Ahmed, I; Jones, I A; Parsons, A J; Bernard, J; Farmer, J; Scotchford, C A; Walker, G S; Rudd, C D

    2011-08-01

    Internal fixation for bone fractures with rigid metallic plates, screws and pins is a proven operative technique. However, refracture's have been observed after rigid internal fixation with metal plates and plate fixation has been known to cause localised osteopenia under and near the plate. In the present study, resorbable composites comprising a PLA matrix reinforced with iron doped phosphate glass fibres were investigated. Non-woven random mat laminates of approximately 30% and 45% fibre volume fraction (V(f)) were produced, along with unidirectional and 0°-90° samples of approximately 20% V(f). The non-woven composite laminates achieved maximum values of 10 GPa modulus and 120 MPa strength. The 0-90º samples showed unexpectedly low strengths close to matrix value (~50 MPa) although with a modulus of 7 GPa. The UD specimens exhibited values of 130 MPa and 11.5 GPa for strength and modulus respectively. All the modulus values observed were close to that expected from the rule of mixtures. Samples immersed in deionised water at 37°C revealed rapid mechanical property loss, more so for the UD and 0-90º samples. It was suggested that continuous fibres wicked the degradation media into the composite plates which sped up the deterioration of the fibre-matrix interface. The effect was less pronounced in the non-woven random mat laminates due to the discontinuous arrangement of fibres within the composite, making it less prone to wicking. Random mat composites revealed a higher mass loss than the UD and 0°-90° specimens, it was suggested this was due to the higher fibre volume fractions of these composites and SEM studies revealed voidage around the fibres by day 3. Studies of pH of the degradation media showed similar profiles for all the composites investigated. An initial decrease in pH was attributed to the release of phosphate ions into solution followed by a gradual return back to neutral.

  15. The High-Frequency Dielectric Properties of Glass Fibre Reinforced Plastic and Honeycomb Layers

    DTIC Science & Technology

    1989-06-29

    The dielectric constant and the dielectric loss angle tangent of glass fibre reinforced plastic are both relatively small; it is a good wave...practical value. This paper introduces the work we have done in this area. The dielectric properties of glass fibre reinforced plastic have a close

  16. Shock Interaction Studies on Glass Fibre Reinforced Epoxy Matrix Composites

    NASA Astrophysics Data System (ADS)

    Reddy, K. P. J.; Jagadeesh, G.; Jayaram, V.; Reddy, B. Harinath; Madhu, V.; Reddy, C. Jaya Rami

    Glass fibre reinforced polymer matrix composites are being extensively used for structural applications both in civil and defense sectors, owing to their high specific strength, stiffness and good energy absorbing capability. Understanding the dynamic response of these composites on shock loading is very essential for effective design of structures resistant to blast loads. In the present study, E- glass/epoxy composite laminate has been fabricated and evaluated for their mechanical properties such as tensile strength, flexural strength and inter laminar shear strength (ILSS). Further, dynamic response of E-glass laminates is presently studied by shock loading. When E-glass composite subjected to peak shock reflected pressure of 7.2 MPa and estimated temperature of about 14000 K for short duration, it underwent surface discolorations and charring of epoxy matrix. Post test analysis of the composite sample was carried out to study the damage analysis using Scanning Electron Microscope (SEM), changes in thermal properties of composites using Dynamic Mechanical Analyzer (DMA) and Thermo-Gravimetric Analyzer (TGA). The results of these investigations are discussed in this paper.

  17. Thermal recycling and re-manufacturing of glass fibre thermosetting composites

    NASA Astrophysics Data System (ADS)

    Fraisse, A.; Beauson, J.; Brøndsted, P.; Madsen, B.

    2016-07-01

    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 to manufacture a new composite laminate with the same fibre architecture as the pristine one. The fibres, the matrix and the composite laminates were thoroughly characterised and analysed. The results show that good materials quality was obtained for both laminates. A difference in fibre packing behaviour was observed in the composites with the pristine and the recycled fibres, which lead to a lower fibre volume fraction in the latter one. The Young's modulus of the composites was not changed by the recycling process, if the lower fibre volume fraction is taken into account. However, a marked drop in the maximum stress of the composites was reported, which was found to be related to the loss in maximum stress of the fibres.

  18. Release of chlorhexidine digluconate and flexural properties of glass fibre reinforced provisional fixed partial denture polymer.

    PubMed

    Lahdenperä, Milla S; Puska, Mervi A; Alander, Pasi M; Waltimo, Tuomas; Vallittu, Pekka K

    2004-12-01

    The objective of this study was to determine the flexural properties and the release of chlorhexidine digluconate (CHX) of CHX laced unidirectional E-glass fibre reinforced provisional fixed partial denture polymer. Bar shaped test specimens (3.3 x 10.0 x 65.0 mm) were fabricated from provisional fixed partial denture polymer (mixture of poly[ethylmethacrylate] powder and n-poly[butyl methacrylate] monomer liquid) with E-glass fibre reinforcements. Poly(methyl methacrylate) preimpregnated continuous unidirectional glass fibre reinforcement was laced with CHX. The glass fibre reinforcements were incorporated into the polymer and the polymerised to the form of test specimens. In addition test specimens without CHX in glass fibre reinforcement were made for comparison. Control specimens did not contain glass fibres in the test specimens. Flexural strength and modulus of test specimens (n = 6) was tested with three-point bending test after storing the specimens dry or in water (two weeks). Released CHX was determined with high performance liquid chromatography during 180 days water immersion. In dry conditions, the flexural strength and the modulus of the polymer was 43 MPa and 1.7 GPa, and with glass fibre reinforcement 96 MPa and 3.5 GPa. With the reinforcement laced with CHX, the strength was 92 MPa and the modulus was 3.2 GPa. The water storage of test specimens did not weaken the reinforced polymer. The majority of the CHX released from the glass fibre reinforced polymer during the first days of storage in water. Flexural properties of provisional fixed partial denture polymer were increased using glass fibre reinforcement. The fibre reinforcement that was laced with CHX resulted in similar reinforcing effect.

  19. Phosphate glass fibres and their role in neuronal polarization and axonal growth direction.

    PubMed

    Vitale-Brovarone, C; Novajra, G; Lousteau, J; Milanese, D; Raimondo, S; Fornaro, M

    2012-03-01

    Phosphate glass fibres with composition 50P(2)O(5)-30CaO-9Na(2)O-3SiO(2)-3MgO-(5-x)K(2)O-xTiO(2)mol.% (x=0, 2.5, 5, respectively coded as TiPS(0), TiPS(2.5) and TiPS(5)) were drawn following the preform drawing approach. A 20-day solubility test in bi-distilled water was carried out on glass fibres with different compositions and diameters ranging between 25 and 82 μm. The results show that the glass composition, the initial fibre diameter and the thermal treatment are the main factors influencing the dissolution kinetics and that the fibres maintain their structural integrity and composition during dissolution. Biological tests were carried out on aligned TiPS(2.5) glass fibres using Neonatal Olfactory Bulb Ensheathing Cell Line (NOBEC) and Dorsal Root Ganglia (DRG) neurons. The fibres showed to be permissive substrates for cell adhesion and proliferation. The aligned configuration of the fibres seemed to provide a directional cue for growing axons of DRG neurons, which showed to sprout and grow long neurites along the fibre axis direction. These promising findings encourages further studies to evaluate the potential use of resorbable glass fibres (e.g.in combination with a nerve guidance tube) for the enhancement of the peripheral nerve healing with the role of supporting and guiding the cells involved in the nerve regeneration.

  20. Parametric Study of End Milling Glass Fibre Reinforced Composites

    SciTech Connect

    Azmi, Azwan I.; Lin, Richard J. T.; Bhattacharyya, Debes

    2011-01-17

    This paper discusses the application of Taguchi 'Design of Experiment' method to investigate the effects of end milling parameters on machinability characteristics of unidirectional E-glass fibre reinforced polymer (GFRP) composites. A series of milling experiments were conducted using tungsten carbide end milling cutters at various spindle speeds, feed rates and depths of cut. Taguchi analysis was carried out and the signal to noise (S/N) ratio with analysis of variance (ANOVA) was employed to analyse the effects of those parameters on GFRP machinability. Overall, the results of the current investigations present some desirable combinations of the machining parameters that can further enhance the end milling machinability characteristics to suit the final requirements of the finished GFRP products.

  1. Glass fibres reinforced polyester composites degradation monitoring by surface analysis

    NASA Astrophysics Data System (ADS)

    Croitoru, Catalin; Patachia, Silvia; Papancea, Adina; Baltes, Liana; Tierean, Mircea

    2015-12-01

    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.

  2. The grindability of glass fibre reinforced polymer composite

    NASA Astrophysics Data System (ADS)

    Chockalingam, P.

    The use of glass fibre-reinforced polymer (GFRP) composite materials is extensive due to their favourable mechanical properties and near net shape production. However, almost all composite structures require post-processing operations such as grinding to meet surface finish requirements during assembly. Unlike that of conventional metal, grinding of GFRP composite needs special tools and parameters due to the abrasive nature of fibres and the delamination of the workpiece. Therefore, proper selection of the tools and parameters is important. This research aims to investigate the effects of wheel speed, feed, depth of cut, grinding wheel and coolant on the grindability of chopped strand mat (CSM) GFRP. Grinding was carried out in a precision CNC (Master-10HVA) high-speed machining centre under three conditions, namely dry, and wet conditions with synthetic coolant and emulsion coolant, using alumina wheel (OA46QV) and CBN wheel (B46QV). The grinding experiments were conducted per the central composite design of design of experiments. The grindability aspects investigated were surface area roughness (Sa) and cutting force ratio (µ). The responses were analyzed by developing fuzzy logic models. The surface area roughness and cutting force ratio values predicted by the fuzzy logic models are mostly in good agreement with experimental data, and hence conclusion was made that these models were reliable.

  3. [Studies on habitat of fungi on glass fibre wallpaper (author's transl)].

    PubMed

    Bemmann, W

    1979-01-01

    The fungi strains Alternaria tenuis C.G. Ness and Ulocladium alternariae (Cke.) Simmons could be isolated from black coloured glass fibre wallpaper. It was investigated that glass fibre wallpaper and covering pastes were not substrate medium but were settled by fungi when there were nutrition substances under or in the air volume of the wallpaper. Both isolated fungi strains converted carboxymethyl-cellulose as alone C- and energy source. The fungicide Smotilon AM limited the spore germination growth of both strains with 0.5% solution. The formation of the biotop glass fibre wallpaper for fungi was discussed.

  4. Production and characterization of polypropylene composites filled with glass fibre recycled from pyrolysed waste printed circuit boards.

    PubMed

    Li, Shenyong; Sun, Shuiyu; Liang, Haifeng; Zhong, Sheng; Yang, Fan

    2014-01-01

    Waste printed circuit boards (WPCBs) are composed of nearly 70% non-metals, which are generally recycled as low-value filling materials or even directly dumped in landfills. In this study, polypropylene (PP) composites reinforced by recycled pure glass fibres (RGF) from pyrolysed WPCBs were successfully produced. The manufacturing process, mechanical properties and thermal behaviour of the composites were investigated. The results showed that the appropriate addition of RGF in the composites can significantly improve the mechanical properties and thermal behaviour. When the added content of RGF was 30%, the maximum increment of tensile strength, impact strength, flexural strength and flexural modulus of the glass fibre (GF)/PP composites are 25.93%, 41.38%, 31.16% and 68.42%, respectively, and the vicat softening temperature could rise by 4.6°C. Furthermore, leaching of the GF/PP composites was also investigated. The GF/PP composites exhibited high performance and non-toxicity, offering a promising method to recycle RGF from pyrolysed WPCBs with high-value applications.

  5. Optical fibre with a germanate glass core for lasing near 2 {mu}m

    SciTech Connect

    Dvoirin, Vladislav V; Mashinskii, Valerii M; Iskhakova, L D; Dianov, Evgenii M; Yashkov, M V; Khopin, V F; Gur'yanov, Aleksei N

    2011-01-24

    An optical fibre with a core based on thulium-doped germanate glass (45SiO{sub 2} - 55GeO{sub 2}) and a quartz glass cladding is developed for the first time. Lasing on Tm{sup 3+} ions ({lambda} =1.862 {mu}m) with an output power up to 70 mW at a differential efficiency of 37% is obtained in a laser based on this fibre. (letters)

  6. Recycling glass fibres from scrap composites using a fluidized bed process

    SciTech Connect

    Kennerley, J.R.; Fenwick, N.J.; Pickering, S.J.; Rudd, C.D.

    1997-12-31

    A new fluidised bed process for the recovery of fibres from scrap composites has been developed. The process involves the thermal decomposition of the polymer in a fluidised bed, with subsequent energy recovery. Clean fibres are then recovered in a form suitable for recycling into new composites. The process is particularly suitable for contaminated or mixed scrap materials and is therefore targeted for the recycling of post consumer scrap, for example, scrap composites from the automotive industry. This paper will briefly describe the process and then focus upon the properties of the glass fibres recovered from the processing of SMC scrap in the laboratory test facility. The effect of the thermal processing on the fibres will be described and optimum processing conditions discussed. Scrap processed at 450{degrees}C results in fibres with a strength reduced to about half that of virgin fibre. With processing above 450{degrees}C there is a greater reduction in strength, but below 450{degrees}C the fibres are still significantly contaminated with polymer. The prospects for the recycling of a range of different types of polymer composite, based on different resins and proportions of fibre and filler, will be discussed. The initial results of the reuse of the recycled fibres in a glass fibre veil product will also be reported.

  7. A nanometallic nickel-coated, glass-fibre-based structural health monitoring system for polymer composites

    NASA Astrophysics Data System (ADS)

    Balaji, R.; Sasikumar, M.

    2017-09-01

    Glass-fibre-reinforced polymer matrix composites are widely used in various industries because of their unique high strength to weight ratio. Unlike metals, strain-induced and damage states of composites are complicated to predict under real-time loading due to their anisotropic nature. With that focus, a piezoresistive nanomaterial-based structural health monitoring system for laminated polymer composites is proposed to measure the strain induced in the composite under real-time loading. Nanometallic nickel-coated glass fibres are embedded into the polymer composites to monitor the strain and damage induced in them. The nanometallic nickel is coated over the glass fibre by a dip coating technique using epoxy as the binding agent. A microcontroller-based electrical resistance measurement system is used to measure the piezoresistive variation in the coated glass fibre under real-time loading. Using the piezoresistance variation of the embedded nanometallic nickel-coated glass fibre, the real-time strain and damage induced in the composite can be correlated. The piezoresistive response of the coated glass fibre is descibed in two phases, the deformation phase and the failure phase, which clearly show the various states of strain and damage induced in the composites.

  8. Fracture strength of teeth with flared root canals restored with glass fibre posts.

    PubMed

    Bonfante, Gerson; Kaizer, Osvaldo Bazzan; Pegoraro, Luiz Fernando; do Valle, Accácio Lins

    2007-06-01

    To investigate the fracture strength and pattern of failure of teeth with weakened roots reconstructed by different procedures. In an in vitro study root posts were placed in 50 endodontically treated canines, divided into 5 groups (n=10) as follows: cast metallic post; glass fibre post with smaller diameter than the root canal; glass fibre post with smaller diameter than the root canal + glass fibre strips; glass fibre post with smaller diameter than the root canal + accessory glass fibre posts; anatomical post (glass fibre post with smaller diameter than the root canal, relined with low viscosity composite resin). Posts were luted with resin cement and the coronal portion of posts was constructed with composite resin. Metallic crowns were cemented on the posts. Specimens were submitted to compressive load in a universal testing machine. Fracture strength values of each group were compared. Fracture strength values were for Groups 1-5 respectively: 1087.06; 745.69; 775.41; 920.64; 876.12kgf, with significant differences between Groups 1 and 2 and between Groups 1 and 3 (p<0.05). Observed patterns of fracture were: Group 1 - 100% of roots fractured; Groups 2 and 4 - variable fracture modes; Group 3 - 60% of fractures occurred in the cervical root third; Group 5 - 50% of failures occurred in the coronal portion of the post. The fracture strength of teeth with cast metallic posts, teeth with anatomical posts or teeth with glass fibre posts combined with accessory posts was similar. All teeth restored with cast metallic posts presented fractures and were unfavourable to maintenance of the remaining tooth structure. Teeth with fibre posts (Groups 2 to 5) presented variable fracture modes; however, the maximum percentage of unfavourable fractures was 30%.

  9. The influence of removing sizing on strength and stiffness of conventional and high modulus E-glass fibres

    NASA Astrophysics Data System (ADS)

    Nørgaard Petersen, Helga; Kusano, Yukihiro; Brøndsted, Povl; Almdal, Kristoffer

    2016-07-01

    Two types of E-glass fibres, a conventional and a high modulus where the last one in the following will be denoted as ECR-glass fibre, were investigated regarding density, diameter, stiffness and strength. The fibres were analysed as pristine and after sizing removal treatments. The sizing was removed by either burning at 565°C or soxhlet extraction with acetone. It was found that the density and the stiffness increased after removing the sizing by the two removal treatments whereas the diameter did not change significantly. The strength of the fibres decreased after burning as the sizing, protecting against water and fibre-fibre damage, had been removed. The strength of the fibres after extraction was not significantly different from the strength of the pristine fibres despite removing the sizing. This indicates that the bonded part of sizing is still protecting the glass fibre surface.

  10. Phosphate glass fibre scaffolds: Tailoring of the properties and enhancement of the bioactivity through mesoporous glass particles.

    PubMed

    Novajra, G; Boetti, N G; Lousteau, J; Fiorilli, S; Milanese, D; Vitale-Brovarone, C

    2016-10-01

    Novel bone glass fibre scaffolds were developed by thermally bonding phosphate glass fibres belonging to the P2O5-CaO-Na2O-SiO2-MgO-K2O-TiO2 system (TiPS2.5 glass). Scaffolds with fibres of 85 or 110μm diameter were fabricated, showing compressive strength in the range of 2-3.5MPa, comparable to that of the trabecular bone. The effect of different thermal treatments and fibre diameters and length on the final scaffold structure was investigated by means of micro-CT analysis. The change of the sintering time from 30 to 60min led to a decrease in the scaffold overall porosity from 58 to 21vol.% for the 85μm fibre scaffold and from 50 to 40vol.% when increasing the sintering temperature from 490 to 500°C for the 110μm fibre scaffold. The 85μm fibres resulted in an increase of the scaffold overall porosity, increased pore size and lower trabecular thickness; the use of different fibre diameters allowed the fabrication of a scaffold showing a porosity gradient. In order to impart bioactive properties to the scaffold, for the first time in the literature the introduction in these fibre scaffolds of a bioactive phase, a melt-derived bioactive glass (CEL2) powder or spray-dried mesoporous bioactive glass particles (SD-MBG) was investigated. The scaffold bioactivity was assessed through soaking in simulated body fluid. CEL2/glass fibre scaffold did not show promising results due to particle detachment from the fibres during soaking in simulated body fluid. Instead the use of mesoporous bioactive powders showed to be an effective way to impart bioactivity to the scaffold and could be further exploited in the future through the ability of mesoporous particles to act as systems for the controlled release of drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Bond strength of fibre glass and carbon fibre posts to the root canal walls using different resin cements.

    PubMed

    Farina, Ana Paula; Cecchin, Doglas; Garcia, Lucas da Fonseca Roberti; Naves, Lucas Zago; Pires-de-Souza, Fernanda de Carvalho Panzeri

    2011-08-01

    The aim of the study was to evaluate the bond strength of fibre glass and carbon fibre posts in the root canal walls cemented with self-adhesive (RelyX-Unicem) and chemical (Cement-Post) resin cements. Forty maxillary canines were divided into four groups according to the cement and post used and submitted to the push-out test (0.5 mm min(-1)). The data were submitted to statistical analysis (2-way ANOVA, Bonferroni--P<0.05) and fracture analysis by Scanning Electronic Microscopy. Fibre glass presented the best results when cemented with RelyX-Unicem and Cement-Post (P<0.05). RelyX-Unicem presented the highest bond strength values for both posts (P<0.05). Fracture analysis showed predominance of cohesive fracture of post for RelyX-Unicem and adhesive fracture between dentin/cement and mixed for Cement-Post. The bond strength values were significantly affected by the type of post and cement used and the highest values were found for fibre glass posts and RelyX-Unicem. © 2010 The Authors. Australian Endodontic Journal © 2010 Australian Society of Endodontology.

  12. Influence of various factors on the breakage rate of glass fibre

    NASA Astrophysics Data System (ADS)

    Setina, J.; Akishins, V.; Petersone, L.; Veseris, V.; Juhnevica, I.

    2011-12-01

    Technical glass fibre fabrics generally are made from alkali-free (R2O<1%) alumina borosilicate E-type continuous glass fibre yarns. These materials have high (up to 600°C) thermal resistivity, low thermal conductivity and are inert to the majority of chemical reagents, resistant to many organic and mineral acids, weak alkali, water and high-pressure steam. E-type glass fibre is used as thermal and acoustic insulating material up to 600°C. The quality of glass fibre as well as of its fabrics depends on many parameters, including quality of raw and refractory materials, furnace construction and parameters, distribution and stoichiometric proportion of chemical elements in filaments, redox ratio in the glass, etc. In order to clarify main causes of filament breakage and surface defects, the morphology and compositional profiles of glass fibre were studied using Fourier Transform Infrared spectroscopy (FTIS), Scanning Electron Microscopy (SEM), X-ray microanalysis and X-ray powder diffraction.

  13. FIBRE OPTICS Mid-IR luminescence of Cr2+ : II — VI crystals in chalcogenide glass fibres

    NASA Astrophysics Data System (ADS)

    Mironov, Roman A.; Karaksina, E. V.; Zabezhailov, A. O.; Shapashnikov, R. M.; Churbanov, M. F.; Dianov, Evgenii M.

    2010-11-01

    Optical fibres have been fabricated for the first time from As2S3 glass containing chromium-doped ZnS and ZnSe crystals, and their optical loss and luminescence spectra have been measured in the mid-IR. In the spectral range 2 — 3 μm, the optical loss in the fibres is 2 — 4 dB m-1. The fibres have a broad luminescence band in the range 1.8 — 3 μm, with a maximum near 1.9 μm, which is due to Cr2+ 5E — 5T2 intracentre transitions in the II - VI host.

  14. Fatigue resistance of acrylic resin denture base material reinforced with E-glass fibres.

    PubMed

    Gurbuz, Ozlem; Dikbas, Idil; Unalan, Fatma

    2012-06-01

    The purpose of the study was to determine the effect of different forms and concentrations (2.5, 3, 4, 5% by volume) of glass fibres (chopped strand mat, continuous and woven) on fatigue resistance of acrylic denture base resin. The fatigue resistance was measured by applying repeated three-point bending deflection to the specimens, the cycle frequency of 1.05 g and magnitude of deflection of 2.0 mm. The number of loading cycles needed to cause a fracture in the test specimen was considered the fatigue resistance of the specimen. The results of this study revealed that the addition of three different glass fibre forms at all concentrations to acrylic resin did not produce a statistically significant increase in the fatigue resistance (p ≥ 0.05). This study also revealed that there were significant differences (p < 0.05) between glass fibres forms used concerning the effects on the fatigue resistance. This study showed that the woven glass fibres had a definite superiority over the chopped fibres and the continuous fibres in regard to the fatigue resistance of the acrylic denture base resin. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

  15. Fracture resistance of structurally compromised root filled bovine teeth restored with accessory glass fibre posts.

    PubMed

    Martelli, H; Pellizzer, E P; Rosa, B T; Lopes, M B; Gonini, A

    2008-08-01

    To evaluate the mechanical behaviour of structurally compromised root filled bovine roots after restoration with accessory glass fibre posts. Fifty roots of bovine teeth received conventional post preparations with a cervical diameter of 3.5 mm. The roots were assigned to five groups (n = 10): group MP - cast metal post, group GP - glass fibre post and group AGP - glass fibre post plus accessory glass fibre posts. In groups GP-R and AGP-R (similar to groups GP and AGP), 2 mm of coronal tooth structure were left intact. All groups were subjected to an elastic limit assay and tested in an universal machine for fracture resistance. Repeated measures anova were performed to examine differences in fracture resistance; fracture modes were analysed by Fischer's exact test. The mean fracture resistance values (kgf) were 61.8 (MP), 63.1 (GP), 55.5 (AGP), 56 (GP-R) and (53.1) AGP-R. No statistically significant difference was found between groups. The Fisher's exact test indicated significant differences (P < 0.05) in the fracture mode amongst groups MP, GP and AGP, indicating 100%, 50% and 10% of catastrophic fractures, respectively. The use of accessory glass fibre posts affected the fracture mode favorably: 90% of fractures in group AGP were in the coronal third.

  16. Flexural properties of crosslinked and oligomer-modified glass-fibre reinforced acrylic bone cement.

    PubMed

    Puska, Mervi A; Närhi, Timo O; Aho, Allan J; Yli-Urpo, Antti; Vallittu, Pekka K

    2004-09-01

    The flexural properties of oligomer-modified bone cement with various quantities of crosslinking monomer with or without glass fibre reinforcement were studied. The flexural strength and modulus of acrylic bone cement-based test specimens (N=6), including crosslinked and oligomer-modified structures with or without glass fibres, were measured in dry conditions and after immersion in simulated body fluid (SBF) for seven days (analysis with ANOVA). One test specimen from the acrylic bone cement group containing 30 wt % crosslinking monomer of its total monomer content was examined with scanning electron microscope (SEM) to evaluate signs of the semi-interpenetrating polymer network (semi-IPN). The highest dry mean flexural strength (130 MPa) was achieved with the bone cement/crosslinking monomer/glass fibre combination containing 5 wt % crosslinking monomer of its monomer content. The highest flexural modulus (11.5 GPa) was achieved with the bone cement/crosslinking monomer/glass fibre combination containing 30 wt % crosslinking monomer of its monomer content. SBF storage decreased the flexural properties of the test specimens, as did the addition of the oligomer filler. Nevertheless, the addition of crosslinking monomer and chopped glass fibres improves considerably the mechanical properties of oligomer-modified (i.e. porosity-producing filler containing) acrylic bone cement. In addition, some signs of the semi-IPN structure were observed by SEM examination.

  17. Mechanical, degradation and cytocompatibility properties of magnesium coated phosphate glass fibre reinforced polycaprolactone composites.

    PubMed

    Liu, Xiaoling; Hasan, Muhammad S; Grant, David M; Harper, Lee T; Parsons, Andrew J; Palmer, Graham; Rudd, Chris D; Ahmed, Ifty

    2014-11-01

    Retention of mechanical properties of phosphate glass fibre reinforced degradable polyesters such as polycaprolactone and polylactic acid in aqueous media has been shown to be strongly influenced by the integrity of the fibre/polymer interface. A previous study utilising 'single fibre' fragmentation tests found that coating with magnesium improved the fibre and matrix interfacial shear strength. Therefore, the aim of this study was to investigate the effects of a magnesium coating on the manufacture and characterisation of a random chopped fibre reinforced polycaprolactone composite. Short chopped strand non-woven phosphate glass fibre mats were sputter coated with degradable magnesium to manufacture phosphate glass fibre/polycaprolactone composites. The degradation behaviour (water uptake, mass loss and pH change of the media) of these polycaprolactone composites as well as of pure polycaprolactone was investigated in phosphate buffered saline. The Mg coated fibre reinforced composites revealed less water uptake and mass loss during degradation compared to the non-coated composites. The cations released were also explored and a lower ion release profile for all three cations investigated (namely Na(+), Mg(2+) and Ca(2+)) was seen for the Mg coated composite samples. An increase of 17% in tensile strength and 47% in tensile modulus was obtained for the Mg coated composite samples. Both flexural and tensile properties were investigated and a higher retention of mechanical properties was obtained for the Mg coated fibre reinforced composite samples up to 10 days immersion in PBS. Cytocompatibility study showed both composite samples (coated and non-coated) had good cytocompatibility with human osteosarcoma cell line.

  18. Mechanical properties and fabrication of small boat using woven glass/sugar palm fibres reinforced unsaturated polyester hybrid composite

    NASA Astrophysics Data System (ADS)

    Misri, S.; Leman, Z.; Sapuan, S. M.; Ishak, M. R.

    2010-05-01

    In recent years, sugar palm fibre has been found to have great potential to be used as fibre reinforcement in polymer matrix composites. This research investigates the mechanical properties of woven glass/sugar palm fibres reinforced unsaturated polyester hybrid composite. The composite specimens made of different layer of fibres such as strand mat, natural and hand woven of sugar palm fibres. The composites were fabricated using a compression moulding technique. The tensile and impact test was carried out in accordance to ASTM 5083 and ASTM D256 standard. The fibre glass boat is a familiar material used in boat industry. A lot of research on fabrication process such as lay-up, vacuum infusion mould and resin transfer mould has been conducted. Hybrid material of sugar palm fibre and fibre glass was used in fabricating the boat. This research investigates the method selection for fabrication of small boat application of natural fibre composites. The composite specimens made of different layer of fibres; woven glass fibre, strand mat, natural and hand woven of woven sugar palm fibres were prepared. The small boat were fabricated using a compression moulding and lay up technique. The results of the experiment showed that the tensile strength, tensile modulus, elongation at break value and impact strength were higher than the natural woven sugar palm fibre. The best method for fabricating the small boat was compression moulding technique. As a general conclusion, the usage of glass fibre had improved the tensile properties sugar palm fibre composites and compression moulding technique is suitable to be used in making a small boat application of natural fibre composites.

  19. Lung cancer among glass fibre production workers: a case-control study.

    PubMed Central

    Gardner, M J; Magnani, C; Pannett, B; Fletcher, A C; Winter, P D

    1988-01-01

    A cohort study among 4734 employees at an English glass fibre plant previously reported no excess of lung cancer mortality either overall or when examined in broad occupational groups. To investigate occupation in more detail, and to test the hypothesis that processes producing or using finer (respirable) fibres may be related to a higher risk of lung cancer, a nested case-control study has now been carried out. Included are 73 cases of lung cancer and 506 matched controls, for whom jobs held and processes worked on have been blindly recorded in more detail than for the cohort study. Workers known to have been employed on processes containing respirable fibres had a relative risk of lung cancer of 1.2 (95% confidence interval 0.7-2.0) compared with other workers. There was no evidence of a relationship of lung cancer to fibre diameter, duration of exposure, or time since first exposure. The results by broad occupational group were similar to those of the cohort study, and although some of the many detailed occupational categories examined had significantly raised relative risks, these did not appear to be related to exposure to respirable glass fibre. Although the study has not indicated a differential risk of lung cancer among workers exposed to finer diameter glass fibres, the exposure levels were low and the number of cases small. PMID:3179236

  20. Optical characterization of a glass fibre with the use of low-coherent light (LED)

    NASA Astrophysics Data System (ADS)

    Świrniak, Grzegorz; Głomb, Grzegorz

    2012-04-01

    The aim of the paper is to discuss a non-invasive method for a glass fibre diameter characterization. The method involves scattering of low-coherent light in the vicinity of a primary rainbow. Theoretical considerations include discussion on complex as well as approximate models of the rainbow. A simple inverse model based on the Airy theory of rainbow is used to characterize a glass fibre diameter. The empirical analysis is mainly devoted to confirm the theoretical predictions and present some achievements in the formation and processing of the Airy rainbow with the use of high-power light emitting diode (LED).

  1. The oxidative stability of carbon fibre reinforced glass-matrix composites

    NASA Technical Reports Server (NTRS)

    Prewo, K. M.; Batt, J. A.

    1988-01-01

    The environmental stability of carbon fibre reinforced glass-matrix composites is assessed. Loss of composite strength due to oxidative exposure at elevated temperatures under no load, static load and cyclic fatigue as well as due to thermal cycling are all examined. It is determined that strength loss is gradual and predictable based on the oxidation of carbon fibres. The glass matrix was not found to prevent this degradation but simply to limit it to a gradual process progressing from the composite surfaces inward.

  2. The oxidative stability of carbon fibre reinforced glass-matrix composites

    NASA Technical Reports Server (NTRS)

    Prewo, K. M.; Batt, J. A.

    1988-01-01

    The environmental stability of carbon fibre reinforced glass-matrix composites is assessed. Loss of composite strength due to oxidative exposure at elevated temperatures under no load, static load and cyclic fatigue as well as due to thermal cycling are all examined. It is determined that strength loss is gradual and predictable based on the oxidation of carbon fibres. The glass matrix was not found to prevent this degradation but simply to limit it to a gradual process progressing from the composite surfaces inward.

  3. Alkaline composite PEO-PVA-glass-fibre-mat polymer electrolyte for Zn-air battery

    NASA Astrophysics Data System (ADS)

    Yang, Chun-Chen; Lin, Sheng-Jen

    An alkaline composite PEO-PVA-glass-fibre-mat polymer electrolyte with high ionic conductivity (10 -2 S cm -1) at room temperature has been prepared and applied to solid-state primary Zn-air batteries. The electrolyte shows excellent mechanical strength. The electrochemical characteristics of the batteries were experimentally investigated by means of ac impedance spectroscopy and galvanostatic discharge. The results indicate that the PEO-PVA-glass-fibre-mat composite polymer electrolyte is a promising candidate for application in alkaline primary Zn-air batteries.

  4. Theoretical study of population inversion in active doped MIR chalcogenide glass fibre lasers (invited).

    PubMed

    Sujecki, S; Oladeji, A; Phillips, A; Seddon, A B; Benson, T M; Sakr, H; Tang, Z; Barney, E; Furniss, D; Sójka, Ł; Bereś-Pawlik, E; Scholle, K; Lamrini, S; Furberg, P

    We study the mechanism of the population inversion in mid-infrared fibre lasers based on a chalcogenide glass host doped with active lanthanide ions. Three lanthanide dopant ions are considered: terbium, dysprosium and praseodymium. We predict the relevant trivalent ion level populations and gain. The simulation parameters were obtained by fabricating and optically characterising a series of trivalent ion doped chalcogenide glass samples. We also provide simple analytical expressions that aid the design of the cascade lasing process.

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

    PubMed

    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.

  6. Rabbit pilot study on the resorbability of three-dimensional bioactive glass fibre scaffolds.

    PubMed

    Moimas, Loredana; Biasotto, Matteo; Di Lenarda, Roberto; Olivo, Alessandro; Schmid, Chiara

    2006-03-01

    Bioactive glass composed of Na2O-K2O-MgO-CaO-B2O3-P2O5-SiO2 is used in this study to manufacture three-dimensional glass fibre scaffolds for a synthetic bone filler material for the treatment of bone defects. The glass is characterized by a large working range, which is the temperature interval at which forming of glass can take place. A preliminary in vivo study on New Zealand skeletally mature rabbit's tibia is reported here. Bone defects were prepared in the medial surfaces of the diaphyses of the tibia. For the first time melt derived three-dimensional bioactive glass fibre constructs were used to fill the cavities. The different implants investigated here were a scaffold with a porosity of 45-50%, scaffold with a porosity of 55-60% and morsels with a porosity of 55-60%. The implanted bone substitutes were dissected after 6 months and evaluated by histological and synchrotron radiation micro tomography analysis. PerioGlas and empty defects were used as positive and negative controls, respectively. The result was that the surgically created tibial defects were healed and new bone formation was found in the medullary cavities. Despite the intrinsic limitations of a pilot study, the preliminary results indicate that in 6 months the glass fibre scaffolds are completely resorbed and that the osteoconductive properties of the filling material are strictly correlated with the structural and morphological characteristics of the bone substitute.

  7. Flexural properties of denture-base polymer reinforced with glass-fibre polysulphone composite.

    PubMed

    Kemp, P L; de Wet, F A; Botha, S J; Levin, J

    2004-06-01

    The aim of this study was to determine the effect of glass-fibre composite reinforcement on the flexural strength and flexural modulus poly-methyl methacrylate (PMMA). Prefabricated electrical glass-fibre polysulphone composite rods (GF/PSu), 3mm in diameter, were incorporated in cylindrical, heat polymerizing PMMA specimens with diameters of 4, 5 and 6mm respectively (n = 10). These specimens were compared with PMMA control groups of similar dimension. A three point loading test was performed in air after storage of specimens in water at 37 degrees C for 8 weeks. The following variables were measured : Flexural Strength (FS) and Flexural Modulus (FM). The data were analyzed using one way analysis of variance (ANOVA). After testing, the fracture zone was evaluated using a scanning electron microscope (SEM). The glass-fibre reinforcement used in this study significantly enhanced both the FM and FS values of PMMA. This enhancement was, however, progressively reduced in relation to an increase in cross-sectional dimension of the specimens. SEM evaluation revealed delamination and fracture of the glass-fibres in the polymer matrix.

  8. Assessment of solvent capsule-based healing for woven E-glass fibre-reinforced polymers

    NASA Astrophysics Data System (ADS)

    Manfredi, Erica; Cohades, Amaël; Richard, Inès; Michaud, Véronique

    2015-01-01

    Vacuum Assisted Resin Infusion Molding (VARIM) with low vacuum pressure difference was used to manufacture woven glass fibre-reinforced epoxy resin plates, with a fibre volume fraction of approx. 50 vol% and containing ethyl phenylacetate (EPA)-filled capsules for self-healing purposes. Capsules were introduced by functionalising the fabrics through manual dispersion. We investigated the capability of autonomously healing delaminations induced by static loading in Mode I and II. Healing did not take place for composite samples; this was attributed to the presence of bare fibres on the crack plane and to the reduction of EPA diffusion into the matrix in the presence of fibres both of which hinder the swelling mechanism responsible for healing the cracks.

  9. Mid-IR luminescence of Cr{sup 2+} : II - VI crystals in chalcogenide glass fibres

    SciTech Connect

    Mironov, Roman A; Zabezhailov, A O; Dianov, Evgenii M; Karaksina, E V; Shapashnikov, R M; Churbanov, M F

    2010-11-13

    Optical fibres have been fabricated for the first time from As{sub 2}S{sub 3} glass containing chromium-doped ZnS and ZnSe crystals, and their optical loss and luminescence spectra have been measured in the mid-IR. In the spectral range 2 - 3 {mu}m, the optical loss in the fibres is 2 - 4 dB m{sup -1}. The fibres have a broad luminescence band in the range 1.8 - 3 {mu}m, with a maximum near 1.9 {mu}m, which is due to Cr{sup 2+} {sup 5}E - {sup 5}T{sub 2} intracentre transitions in the II - VI host. (fibre optics)

  10. Phosphate glass core/silica clad fibres with a high concentration of active rare-earth ions

    NASA Astrophysics Data System (ADS)

    Egorova, O. N.; Galagan, B. I.; Denker, B. I.; Sverchkov, S. E.; Semjonov, S. L.

    2016-12-01

    We report a study of silica-clad composite optical fibres having a phosphate glass core doped with active rare-earth elements. The phosphate glass core allows a high concentration of active rare-earth ions to be obtained, and the silica cladding ensures high mechanical strength and facilitates fusion splicing of such fibres to silica fibres. Owing to the high concentration of active rare-earth ions, this type of fibre is potentially attractive for applications where a small cavity length and high lasing efficiency are needed.

  11. Cast metal vs. glass fibre posts: a randomized controlled trial with up to 3 years of follow up.

    PubMed

    Sarkis-Onofre, Rafael; Jacinto, Rogério de Castilho; Boscato, Noéli; Cenci, Maximiliano Sérgio; Pereira-Cenci, Tatiana

    2014-05-01

    This randomized controlled trial compared the survival of glass fibre and cast metal dental posts used to restore endodontically treated teeth with no remaining coronal wall. Fifty-four participants (45 women) and 72 teeth were evaluated during a follow-up period of up to 3 years. Teeth were randomly allocated to the glass-fibre and cast-metal post groups. All teeth were restored with single metal-ceramic crowns. Survival probabilities were analyzed using Kaplan-Meier statistics (p≤0.05). The 3-year recall rate was 92.3% and the survival rates of glass fibre and cast metal posts were similar (97.1% and 91.9%, respectively; p=0.682). Four failures were observed: two glass fibre posts in a premolar and anterior tooth debonded, one glass fibre post in a premolar debonded in association with root fracture, and one root fracture occurred in a molar with a cast metal post. Glass fibre and cast metal posts showed similar clinical performance in teeth with no remaining coronal wall after 3 years. Posts are used to restore most endodontically treated teeth with no remaining coronal wall. This randomized controlled trial, one of few to compare glass fibre and cast metal posts in such teeth, showed that post type did not significantly influence the survival of restorations. These results can help dentists respond to the important question of how best to rehabilitate endodontically treated teeth with no remaining coronal wall. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Glass fibre polyester composite with in vivo vascular channel for use in self-healing

    NASA Astrophysics Data System (ADS)

    Fifo, Omosola; Ryan, Kevin; Basu, Biswajit

    2014-09-01

    The embedment of adhesive-filled hollow glass fibres (HGF) has been reported as a way of combating micro-crack development in fibre-reinforced polymer (FRP) structures. However, hollow fibres can critically undermine the effectiveness of self-healing systems and have been reported to be a potential impediment to the healing agent flow path. On the other hand, attempting to use non-hollow vascular systems in higher dimensions has largely been restricted to bulk polymers that lack reinforcing fibres. This paper investigates an alternative technique where a simple two-dimensional (2D) network of hollow channels is created within a glass-fibre-reinforced polyester-composite structure. The network is created using a fugitive preforming material at the ply level of interest, similar to a direct ink writing procedure. The temporary structure is extracted as a part of the curing and post-curing processes. The channels formed are used to deliver cyanoacrylate adhesive (CA) to areas that have been damaged under a flexural three-point bending test. Subsequent post-repair mechanical testing, under the same mode, evaluates the success of the repair process. The results show good recovery of the stiffness, a paramount mechanical property, and indicate how the grade of the repairing agent used influences the recovered loading strength of the FRP samples.

  13. Fracture resistance of root filled molar teeth restored with glass fibre bundles.

    PubMed

    Rodrigues, F B; Paranhos, M P G; Spohr, A M; Oshima, H M S; Carlini, B; Burnett, L H

    2010-05-01

    To evaluate the effect of unidirectional or woven glass fibre tapes inserted into MOD cavity preparations on the fracture resistance of root filled molar teeth. Extracted human molar teeth were randomly divided into six groups (n = 15) : G1 - sound teeth, control; G2 - MOD cavity preparation; G3 - MOD + root canal treatment (Endo); G4 - MOD + Endo + composite resin restoration (Resin); G5 - MOD + Endo + unidirectional fibre (UF) + Resin; G6 - MOD + ;Endo + woven fibre (WF) + Resin. The teeth were subjected to a compressive fracture test in a universal testing machine. After testing, two failure modes were classified: pulp chamber floor or cusp. The highest and the lowest mean fracture strengths were found in sound teeth (G1) (4960N) and MOD + root canal treatment (G3) (612.84N), respectively, with significant differences from the other groups (P < 0.05). The remaining groups had statistically similar means. In G5 and G6, there was a tendency for fracture to occur in the pulp chamber floor compromising tooth integrity. The insertion of glass fibres into MOD cavity preparations and restoring them with composite resin was not different than molar teeth filled with composite resin only in terms of fracture resistance. Fibres placed into MOD cavities do not reinforce teeth.

  14. Effect of woven glass fibre reinforcement on the flexural strength of composites.

    PubMed

    Oberholzer, T G; du Preez, I C; Lombard, R; Pitout, E

    2007-10-01

    To measure and compare the flexural strength of composites reinforced with fibres, four groups of specimens (N = 10) were prepared from the combinations: Filtek Flow/Filtek Z250 and Esthet-X flow/Esthet-X dental composite. One group from each combination was reinforced with woven glass fibre (everStick net) and all the specimens subjected to three-point bend flexural testing. The mean and standard deviations for each test group were calculated and compared using one-way analysis of variance (ANOVA) followed by pairwise Bonferroni T-tests at a preset alpha of p < 0.05. It was found that fibre reinforcement significantly (p < 0.001) increased the flexural strength of both types of composites. As the inclusion of only one layer of glass fibre net produced an increase of approximately 30% in the flexural strength of the composite samples, it can be speculated that multiple layers would increase it even more. The use of fibre-reinforcement to strengthen directly placed composite crowns and bridges will enable the clinician to provide a more cost effective service as well as aesthetic dentistry to more patients.

  15. Flexural strength of glass fibre-reinforced posts bonded to dual-cure composite resin cements.

    PubMed

    Davis, Peter; Melo, Luciana S D; Foxton, Richard M; Sherriff, Martyn; Pilecki, Peter; Mannocci, Francesco; Watson, Timothy F

    2010-04-01

    The aims of this study were to evaluate the flexural strength of two different types of glass fibre-reinforced posts bonded to dual-cure composite resin cements. Forty glass methacrylate-based fibre posts (GC Fiber Post) and 20 glass fibre inter-polymerizing network posts (everStick POST) were divided into three groups. Group 1 contained 20 GC posts that were bonded to a dual-cure composite cement (UnifilCore). Group 2 contained 20 Stick Tech posts that had adhesive applied (Scotchbond Multipurpose resin) and were bonded to a dual-cure composite resin cement (RelyX Unicem). Group 3 contained 20 GC posts that were pretreated with a silane-coupling agent before being treated with resin and composite, as in group 1. A 4-point bend test was carried out to failure on all of the groups. Failure modes were determined using scanning electron microscopy. Pretreatment of the post surface with the silane-coupling agent did not increase the flexural strength. The flexural strength of the Stick Tech post was significantly lower than the flexural strength of the GC post. The mode of failure for the GC Posts was adhesive, whereas the Stick Tech posts failed cohesively. Different flexural strengths and failure modes were observed among the two fibre post-resin systems.

  16. Production of reactive oxygen species by phagocytic cells after exposure to glass wool and stone wool fibres - effect of fibre preincubation in aqueous solution.

    PubMed

    Zoller, T; Zeller, W J

    2000-04-03

    The potential of four man-made vitreous fibres (MMVFs) (glass wool Code A, stone wool Code G, HT-N and MMVF 21) and of two natural mineral fibres (crocidolite, erionite) to induce production of reactive oxygen species (ROS) by differentiated HL-60 cells (HL-60-M cells) was investigated by determination of luminol-enhanced chemiluminescence (CL). Quartz served as positive control. The same system was used to uncover possible influences of fibre preincubation in aqueous solutions on the ROS-generating potential. Following preincubation in unbuffered saline over about 4 weeks, Code A and G fibres showed decreased ROS-generating potential as compared to freshly suspended fibres. On the other hand, MMVF 21 and HT-N fibres as well as crocidolite and erionite showed no decreased CL after incubation in aqueous solutions. The observed decrease of the ROS-generating potential of Code A and G fibres after preincubation may be an expression of fibre surface alterations (leaching, initiation of dissolution) that influences the response of exposed phagocytic cells. After incubation of both fibres in buffered solutions at different pH values (5.0, 7.4) a reduced ROS-generating potential was still discernible as compared to freshly suspended fibres.

  17. Some aspects of the tensile strength of undirectional glass fibre-polymethyl methacrylate composite used in dentures.

    PubMed

    Vallittu, P K

    1998-02-01

    The aim of this study was to determine the tensile strength and E-modulus of unidirectional denture glass fibre-polymethyl methacrylate (GF-PMMA) composite with various fibre contents. The experimental values of tensile strength and E-modulus were compared with values obtained by a theoretical calculation. Autopolymerized PMMA test specimens (n = 6, per group) were reinforced with unidirectional E-glass fibres which had been wetted in a mixture of PMMA powder and monomer liquid. After storing the test specimens for 40 days in water at 37 degrees C, the tensile strength and E-modulus of the test specimens were measured. The increased amount of fibres in the PMMA matrix (up to 14.8% by weight) increased the mean tensile strength of the test specimens from 40.5 MPa to 91.2 MPa (P < 0.001) and the E-modulus from 2057 MPa to 3751 MPa (P < 0.001). The experimental tensile strength and Emodulus values were considerably lower than those based on the theoretical calculations. This was assumed to be due to the percentage of glass fibres unimpregnated with the PMMA resin. The presence of unimpregnated glass fibres was determined using light microscopy. The results of this study suggest that a new method of incorporating the glass fibres into the PMMA resin matrix should be developed in order to obtain a well-impregnated fibre composite reinforcement with high durability.

  18. Interface modification during oxidation of a glass-ceramic matrix/SiC fibre composite

    SciTech Connect

    Daniel, A.M.; Martin-Meizoso, A.; Plucknett, K.P.; Braski, D.N.

    1996-04-01

    Oxidation heat treatments between 375{degrees}C and 600{degrees}C for 100 hours in air, have been performed on the calcium aluminosilicate glass-ceramic matrix/SiC fibre reinforced composite CAS/Nicalon (manufactured by Coming, USA). Using a commercial nano-indentation system to perform fibre push-down tests, the fibre-matrix interfacial debond fracture surface energy (G{sub i}) and frictional shear stress ({tau}) have been determined. Modification of interface properties, compared to the as fabricated material, was observed at heat treatment temperatures as low as 375{degrees}C, where a significant drop in G{sub i} and an increase in {tau} were recorded. With 450{degrees}C, 525{degrees}C and 600{degrees}C heat treatments, an increase in G{sub i} but a dramatic increase in {tau} were recorded. Under four-point flexure testing, the as fabricated and the 375{degrees}C heat treated materials displayed tough, composite behaviour with extensive fibre pull out, but at {le}450{degrees}C, brittle failure with minimal fibre pull out, was observed. This transition from tough mechanical response to one of brittleness is due to the large increase in {tau} reducing fibre pull out to a minimum and therefore reducing the total required work of fracture. The large increases in {tau} and G{sub i} have been attributed to the oxidative removal of the lubricating, carbon interface and the compressive residual stresses across the interface.

  19. Interface modification during oxidation of a glass-ceramic matrix/SiC fibre composite

    SciTech Connect

    Daniel, A.M.; Martin-Meizoso, A.; Plucknett, K.P.; Braski, D.N.

    1996-12-31

    Oxidation heat treatments between 375{degrees}C and 600{degrees}C for 100 hours in air, have been performed on the calcium aluminosilicate glass-ceramic matrix/SiC fibre reinforced composite CAS/Nicalon (manufactured by Corning, USA). Using a commercial nano-indentation system to perform fibre push-down tests, the fibre-matrix interfacial debond fracture surface energy (G{sub i}) and frictional shear stress ({tau}) have been determined. Modification of interface properties, compared to the as-fabricated material, was observed at heat treatment temperatures as low as 375{degrees}C, where a significant drop in G{sub i} and an increase in {tau} were recorded. With 450{degrees}C, 525{degrees}C and 600{degrees}C heat treatments, an increase in G{sub i} but a dramatic increase in {tau} were recorded. Under four-point flexure testing, the as fabricated and the 375{degrees}C heat treated materials displayed tough, composite behaviour with extensive fibre pull out, but at {ge}450{degrees}C, brittle failure with minimal fibre pull out, was observed. This transition from tough mechanical response to one of brittleness is due to the large increase in {tau} reducing fibre pull out to a minimum and therefore reducing the total required work of fracture. The large increases in {tau} and G{sub i} have been attributed to the oxidative removal of the lubricating, carbon interface and the compressive residual stresses across the interface.

  20. An in vitro investigation of bond strength of veneering composite resin to glass fibre veil reinforced composite.

    PubMed

    Keski-Nikkola, M S; Lassila, L V J; Vallittu, P K

    2004-06-01

    Experimental light-curing polymer-monomer-gel-impregnated E-glass-fibre veil reinforced composite (i.e. a composite with randomly oriented fibres) was used as an adhesional substrate for veneering composite resin (VCR). Continuous unidirectional glass fibre composite was used as a control substrate. Both the fibre-reinforced composite substrate surfaces were ground or, optionally, the substrate surface was left untreated (containing oxygen-inhibited resin layer) before attaching to the VCR. No adhesive resin was used between the composites. Shear bond strength of VCR to the substrate was determined for dry and thermocycled specimens. The results of this study suggested that the VCR can better be bonded to the randomly oriented veil fibre-reinforced composite substrate than to the continuous unidirectional fibre-reinforced composite substrate.

  1. Effect of thermally deposited siloxane-methacrylate coating on bonding to glass fibre posts.

    PubMed

    Silva, F P; Faria-E-Silva, A L; Moraes, R R; Ogliari, A O; Reis, G R; Oliveira, A R F; Menezes, M S

    2017-04-25

    To evaluate the alterations promoted by a thermally deposited siloxane-methacrylate coating on the surface of glass fibre posts and their effect on the bond strength of resin-core materials to the posts. Fibre post surfaces were treated with experimental thermally deposited siloxane-methacrylate coatings or clinically available treatments (i.e. hydrogen peroxide and methylene chloride); nontreated posts were used as controls. The contact angles formed between the post surface and the water/adhesive were measured with a tensiometer. Scanning electron microscopy and electron dispersive spectroscopy were used to examine the topographies and chemical changes in the post surfaces following treatment. Surface roughness was evaluated with laser interferometry. Core resin was bonded to the fibre posts, and microtensile bond strength testing was subsequently performed. The data were individually submitted to anova and Tukey's tests (α = 0.05). The water contact angle was reduced significantly (P < 0.05) by the thermally deposited siloxane-methacrylate coating. All treatments significantly increased the adhesive contact angle (P ≤ 0.016) compared to the control as well as the surface roughness (P ≤ 0.006) and the amount of Si on post surfaces. Greater percentages of Si were observed for the thermally deposited coating. The bond strength to the posts was significantly improved by the thermally deposited coating (P < 0.05), whereas the other treatments did not differ from the control. Treating the surface of glass fibre posts with a thermally deposited siloxane-methacrylate coating improved the bond strength to resin-based materials. The coating could be performed by manufacturers of glass fibre posts in order to reduce the number of clinical steps required for luting posts into root canals. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  2. Cytocompatibility, degradation, mechanical property retention and ion release profiles for phosphate glass fibre reinforced composite rods.

    PubMed

    Felfel, R M; Ahmed, I; Parsons, A J; Palmer, G; Sottile, V; Rudd, C D

    2013-05-01

    Fibre reinforced composites have recently received much attention as potential bone fracture fixation applications. Bioresorbable composites based on poly lactic acid (PLA) and phosphate based glass fibre were investigated according to ion release, degradation, biocompatibility and mechanical retention profiles. The phosphate based glass fibres used in this study had the composition of 40P2O5-24MgO-16CaO-16Na2O-4Fe2O3 in mol% (P40). The degradation and ion release profiles for the composites showed similar trends with the amount of sodium and orthophosphate ions released being greater than the other cations and anions investigated. This was attributed to low Dietzal's field strength for the Na(+) in comparison with Mg(2+) and Ca(2+) and breakdown of longer chain polyphosphates into orthophosphate ions. P40 composites exhibited good biocompatibility to human mesenchymal stem cells (MSCs), which was suggested to be due to the low degradation rate of P40 fibres. After 63 days immersion in PBS at 37 °C, the P40 composite rods lost ~1.1% of mass. The wet flexural, shear and compressive strengths for P40 UD rods were ~70%, ~80% and ~50% of their initial dry values after 3 days of degradation, whereas the flexural modulus, shear and compressive strengths were ~70%, ~80%, and ~65% respectively. Subsequently, the mechanical properties remained stable for the duration of the study at 63 days. The initial decrease in mechanical properties was attributed to a combination of the plasticisation effect of water and degradation of the fibre-matrix interface, with the subsequent linear behaviour being attributed to the chemical durability of P40 fibres. P40 composite rods showed low degradation and ion release rates, good biocompatibility and maintained mechanical properties similar to cortical bone for the duration of the study. Therefore, P40 composite rods have huge potential as resorbable intramedullary nails or rods. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Numerical Modelling of Glass Fibre Reinforced Laminates Subjected to a Low Velocity Impact

    SciTech Connect

    Fan, J. Y.; Guana, Z. W.; Cantwell, W. J.

    2010-05-21

    This paper presents a series of numerical predictions of the perforation behaviour of glass fibre laminates subjected to quasi-static and low-velocity impact loading. Both shear and tensile failure criteria were used in the finite element models to simulate the post-failure processes via an automatic element removal procedure. The appropriate material properties, obtained through a series of uniaxial tension and bending tests on the composites, were used in the numerical models. Four, eight and sixteen ply glass fibre laminates panels were perforated at quasi-static rates and under low-velocity impact loading. Reasonably good correlation was obtained between the numerical simulations and the experimental results, both in terms of the failure modes and the load-deflection relationships before and during the penetration phase. The predicted impact energies of the GFRP panels were compared with the experimental data and reasonable agreement was observed.

  4. Photochemistry in a soft-glass single-ring hollow-core photonic crystal fibre.

    PubMed

    Cubillas, Ana M; Jiang, Xin; Euser, Tijmen G; Taccardi, Nicola; Etzold, Bastian J M; Wasserscheid, Peter; Russell, Philip St J

    2017-03-13

    A hollow-core photonic crystal fibre (HC-PCF), guided by photonic bandgap effects or anti-resonant reflection, offers strong light confinement and long photochemical interaction lengths in a microscale channel filled with a solvent of refractive index lower than that of glass (usually fused silica). These unique advantages have motivated its recent use as a highly efficient and versatile microreactor for liquid-phase photochemistry and catalysis. In this work, we use a single-ring HC-PCF made from a high-index soft glass, thus enabling photochemical experiments in higher index solvents. The optimized light-matter interaction in the fibre is used to strongly enhance the reaction rate in a proof-of-principle photolysis reaction in toluene.

  5. Glass beads and Ge-doped optical fibres as thermoluminescence dosimeters for small field photon dosimetry.

    PubMed

    Jafari, S M; Alalawi, A I; Hussein, M; Alsaleh, W; Najem, M A; Hugtenburg, R P; Bradley, D A; Spyrou, N M; Clark, C H; Nisbet, A

    2014-11-21

    An investigation has been made of glass beads and optical fibres as novel dosimeters for small-field photon radiation therapy dosimetry. Commercially available glass beads of largest dimension 1.5 mm and GeO2-doped SiO2 optical fibres of 5 mm length and 120 µm diameter were characterized as thermoluminescence dosimeters. Results were compared against Monte-Carlo simulations with BEAMnrc/DOSXYZnrc, EBT3 Gafchromic film, and a high-resolution 2D-array of liquid-filled ionization chambers. Measurements included relative output factors and dose profiles for square-field sizes of 1, 2, 3, 4, and 10 cm. A customized Solid-Water® phantom was employed, and the beads and fibres were placed at defined positions along the longitudinal axis to allow accurate beam profile measurement. Output factors and the beam profile parameters were compared against those calculated by BEAMnrc/DOSXYZnrc. The output factors and field width measurements were found to be in agreement with reference measurements to within better than 3.5% for all field sizes down to 2 cm2 for both dosimetric systems, with the beads showing a discrepancy of no more than 2.8% for all field sizes. The results confirm the potential of the beads and fibres as thermoluminescent dosimeters for use in small photon radiation field sizes.

  6. Modelling of ultrasound tomography technique for Glass Fibre Reinforced Epoxy (GFRE) composites liquid transportation pipeline

    NASA Astrophysics Data System (ADS)

    Siow, L. T.; Rahiman, M. H. F.; Majid, M. S. Abdul; Rahim, R. A.; Zakaria, Z.; Thomas W. K., T.; Ang, Vernoon

    2017-03-01

    The purpose of this paper is to model the ultrasonic tomography on the E-glass fibre reinforced epoxy composite pipe for process monitoring and control. Finite element software and mathematical estimation were applied to model and study the ultrasound wave propagation, especially the reflection and transmission coefficient. While there is a significant result achieved between mathematical estimation and finite element analysis with maximum percentage distinctly in 2.33.

  7. Effect of luting cement and thermomechanical loading on retention of glass fibre posts in root canals.

    PubMed

    Li, Xiao-jing; Zhao, San-jun; Niu, Li-na; Tay, Franklin R; Jiao, Kai; Gao, Yu; Chen, Ji-hua

    2014-01-01

    To evaluate the effect of luting cement and thermomechanical loading on the retention of glass fibre posts in root canals. One hundred and forty-four single-rooted human premolars were endodontically treated and restored with RelyX Fibre Posts. The teeth were divided into four groups according to the cements used (Fuji I, Fuji CEM, RelyX Unicem and RelyX ARC). Each group was further divided into two subgroups according to the method of ageing (immediately tested and after thermomechanical loading). Bond strength was evaluated using a pull-out test. Microleakage was examined quantitatively with dye penetration. The dentine-cement-post bonding interface was assessed using scanning electron microscopy. Data were analysed with two-way ANOVA (pull-out test) and Kruskal-Wallis analysis (microleakage). The pull-out bond strength and microleakage were significantly affected by the type of cement and ageing. Although RelyX ARC showed the highest bond strength before thermomechanical loading (p<0.05), the sealing ability of this cement was worse than those exhibited in Fuji CEM and RelyX Unicem (p<0.05). After thermomechanical loading, pull-out strengths of Fuji I and Fuji CEM were significantly increased, whereas that of RelyX ARC group significantly decreased (p<0.05). The sealing ability of Fuji CEM was significantly better than the two resin cement groups (p<0.05) after ageing. Fuji CEM demonstrates increased pull-out strength after thermomechanical loading and favourable sealing ability compared with the other cements. Resin-modified glass ionomer cements have the potential benefit of achieving long-term retention when used for luting glass fibre post to root canal dentine. So it may be recommended for the cementation of glass fibre post in clinics. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. A glass fibre membrane platform for ultra-sensitive detection of cardiac troponin T.

    PubMed

    Song, Keum-Soo; Nimse, Satish Balasaheb; Sonawane, Mukesh Digambar; Lin, Yahui; Zhou, Zhou; Kim, Taisun

    2017-10-09

    A glass fibre membrane platform that allows quantification of circulating cTnT with a LoD of 0.87 pg mL(-1) is described. The proposed platform uses a glass fibre membrane, DNA-guided detection method, and antibody-conjugated fluorescent beads for the quantification of cTnT in the analytical detection range of 1-120 pg mL(-1) at room temperature in 30 min. Glass fibre membranes were chemically modified to immobilize the oligonucleotide probes that catch a biomolecular complex (FB-dAB-cTnT-cAB-DNA) containing complementary oligonucleotides. There were no interferences from human cTnI, cTnC, skTnT, biotin, and hemoglobin (each 1 μg mL(-1)). The linearity in the serial dilution test of plasma samples indicates that this platform is highly applicable for regular health check-up to assess the risk of AMI and HF.

  9. The transverse mechanical behaviour of glass fibre reinforced plastics

    NASA Astrophysics Data System (ADS)

    Wells, Garry Michael

    The importance of transverse cracking in composites technology is highlighted by the use of classical lamination theory to predict the sequential damage process in cross-plied laminates. The literature on transverse fibre carposite behaviour is comprehensively reviewed, with particular emphasis on papers which present quantitative theoretical models. No work reviewed has measured the full range of mechanical properties on a single material necessary to allow a complete assessment of all the models of transverse failure. A resin system, based on epoxy/urethane blends, has been identified which allows production of high quality unidirectional composites with a systematic variation in flexibility. A preliminary experimental programme has identified those test specimens which can provide the necessary stress/strain and toughness properties of the range of flexibilised materials and thereby allow a validation of the theoretical models reviewed. In the preliminary experimental programme, transverse cracks are shown to extend with an increasing fracture toughness due to the formation of a 'tied zone' of fracture face bridging 'stringers' behind the crack tip. The influence of this effect on crack stability is discussed. By modelling the balance between fracture and strain energies, the equilibrium state of individual stringers is predicted. Direct observations of equilibrium stringer angles are seen to correspond with these predictions. A quite general model is developed which predicts, with reasonble accuracy, the observed increase of fracture toughness with crack extension and the geometry dependence of this increase. The literature models of stiffness, strength and failure strain are seen to display a dissappointing lack of agreement with the experimental results over the full range of material flexibilities. The influence of matrix Poisson constraint on these properties is discussed. Fracture toughness results indicate that very large critical defects control

  10. The effect of two root canal sealers on the retentive strength of glass fibre endodontic posts.

    PubMed

    Davis, S T; O'Connell, B C

    2007-06-01

    This study was undertaken to examine the effect of eugenol-containing and non-eugenol-containing root canal sealers on the retention strength of glass fibre endodontic posts (ParaPost Fibre White) luted with a resin cement (ParaPost cement). We also examined the mode of failure that occurred visually by using scanning electron microscopy. Seventy-two single rooted, recently extracted, premolar teeth were root canal treated and randomly divided into two groups. Group 1 was obturated with gutta percha and a calcium hydroxide-based sealer (Sealapex, Kerr). Group 2 was obturated with gutta percha and a eugenol-based sealer (Tubli-Seal Kerr). The teeth were stored for 1 week in distilled water at 37 degrees C and then prepared for 9 mm posts with a 1.40-mm drill. The matching glass fibre post was luted with a resin cement following the manufacturer's instructions. The samples were stored for 1 week and thermocycled. The posts were removed from the root canals using a calibrated testing machine in tensile mode. The mean dislodging force for group 1 was 190.46 N and for group 2 was 183.8 N, with standard deviations of 54.9 and 56.0 N respectively. The t-test indicated no significant difference between the two groups. Failure of the posts occurred mainly within the resin layer. This study showed that under experimental conditions there was no statistically significant difference between Sealapex sealer and Tubli-Seal sealer on the retention of glass fibre posts using a resin cement.

  11. Glass fibre-reinforced composite laced with chlorhexidine digluconate and yeast adhesion.

    PubMed

    Waltimo, T; Luo, G; Samaranayake, L P; Vallittu, P K

    2004-02-01

    The aim of this study was to lace dental glass fibre reinforced composite (FRC) prepreg with chlorhexidine digluconate and to examine the adherence of common oral fungal pathogen Candida albicans to FRC made of the prepreg. Four different test and control material groups each comprising 16 test specimens ((5.0 x 5.0 x 0.8) mm3) each were used as substrates for C. albicans adherence. A porous polymer pre-impregnated woven glass fibre prepreg was laced with solution of chlorhexidine gluconate and it was used with autopolymerized denture base polymer to fabricate FRC test specimens. Control group (Group 1) consisted of FRC test specimens stored in water. In Group 2, the test specimens were stored in 10% chlorhexidine digluconate solution for 24 h. Group 3 consisted of specimens fabricated using such fibre reinforcements which were pre-soaked in 20% chlorhexidine digluconate and dried before preparation with denture base resin, and followed by storage of the specimens in water. Group 4 was similar to Group 3 but instead of water storage the specimens were immersed in 10% chlorhexidine digluconate for 24 h. For the candidal adhesion assay the test and control specimens were incubated in standardized suspensions of four different strains of C. albicans, rinsed and prepared for light-microscopy. The mean number of adherent cells in each group was counted microscopically and analysed statistically. There were significantly (P < 0.05) more adherent C. albicans cells found in Group 1 than in the other three groups which did not differ significantly from each other. The lowest numbers of adherent cells were found in Group 3. Pretreating the porous polymer pre-impregnated glass fibre reinforcement with chlorhexidine digluconate result in reduction in the number of adherent yeast cells on the surface FRC material.

  12. Marginal adaptation and fracture resistance of adhesively luted glass fibre-composite reinforced molar crowns with different inner crown surfaces.

    PubMed

    Behr, M; Rosentritt, M; Sikora, M I; Karl, P; Handel, G

    2003-09-01

    This study compared the influence of different inner crown surfaces on the fracture resistance and marginal adaptation of adhesively fixed glass fibre-reinforced molar crowns. Vectris/Targis crowns were constructed with an inner framework of glass fibres (directly on the tooth) or an inner veneering composite layer between the fibre-framework and the tooth-substance. Both groups were sandblasted inside using Al(2)O(3); 50 microm grain size (200 kPa, 20 s) and silane coated. A control group had the inner fibre framework, but was neither sandblasted nor silane coated. The crowns were adhesively cemented on extracted human teeth, and thermally cycled and mechanically loaded (TCML: 6000 x 5 degrees C/55 degrees C; 1.2 x 10(6) x 50 N, 1.66 Hz). The marginal adaptation before and after TCML was evaluated and the fracture resistance was investigated using a Zwick universal testing machine. After TCML the proportion of 'perfect margin' of the control group decreased significantly at the interface crown/cement. For the variations with an inner fibre framework or inner composite layer the marginal adaptation or fracture resistance did not decrease significantly after ageing. The fracture resistance values were control: 1509N+/-486; inner fibre framework: 1896N+/-342; inner composite layer: 1754N+/-340. In the case of the investigated fibre framework and veneering composite, the inner surface of glass fibre-reinforced molar crowns can be covered with a composite layer or with a glass fibre framework. Both methods achieve comparable high fracture strengths and reliable marginal adaptation.

  13. Bonding self-adhesive resin cements to glass fibre posts: to silanate or not silanate?

    PubMed

    Oliveira, A S; Ramalho, E S; Ogliari, F A; Moraes, R R

    2011-08-01

    To evaluate the bond strength of self-adhesive resin cements (SARCs) to glass fibre posts with or without a silane coupling agent. The SARCs tested were: Maxcem Elite (MXE; Kerr), RelyX Unicem clicker (UNI; 3M ESPE), seT capsule (SET; SDI), and SmartCem 2 (SC2; Dentsply Caulk). The conventional cement RelyX ARC (ARC; 3M ESPE) was evaluated as a reference. Rectangular-shaped flat posts were obtained (Angelus). After silanizing or not the posts, resin cement cylinders were built on the post surfaces. The cylinders were tested in shear after 24 h. Bond strength data were submitted to two-way anova and Student-Newman-Keuls' test (5%). Failure modes were classified under magnification as adhesive failure, mixed failure involving the cement or mixed failure involving the post. For ARC, MXE and SET, the silanated groups had higher bond strengths. For SC2 the silane had no influence, while for UNI silanization decreased the bond strength. The conventional ARC had the lowest bond strength when the posts were not silanated; UNI showed the highest values. When the posts were silanated, SET had the highest values, followed by MXE, ARC and SC2; UNI had the lowest values. A predominance of adhesive failures was detected for all groups, with higher number of mixed failures when the posts were silanated. As the silane impaired or generally had no effect on the bond strength of SARCs to the glass fibre posts, and also as the bond strength of all SARCs was higher than the conventional cement when the posts were not silanated, it seems that silanization of glass fibre posts is not necessary when SARCs are used. © 2011 International Endodontic Journal.

  14. Glass fibre reinforced versus multistranded bonded orthodontic retainers: a 2 year prospective multi-centre study.

    PubMed

    Tacken, Michel P E; Cosyn, Jan; De Wilde, Peter; Aerts, Johan; Govaerts, Elke; Vannet, Bart Vande

    2010-04-01

    The objective of this study was to compare glass fibre reinforced (GFR) with multistranded bonded orthodontic retainers in terms of success rate and periodontal implications. A 2 year parallel study was conducted of 184 patients scheduled to receive bonded retainers in the upper and lower anterior segments. In three centres, the patients (mean age 14 years; 90 males and 94 females) were sequentially assigned to receive GFR retainers containing 500 unidirectional glass fibres (GFR500), 1000 unidirectional glass fibres (GFR1000), or multistranded retainers (gold standard). Retainer failures and periodontal conditions were monitored every 6 months. In a control group of 90 subjects without retainers, periodontal conditions were examined (negative control). Of the 274 recruited patients, 15 dropped out during the 2 year study period. Kaplan-Meier plots were drawn to assess survival of the different retainers. The Mantel-Cox log-rank test was used to identify significant differences in survival functions among the groups. Repeated measures analysis of variance and appropriate post hoc tests were adopted to evaluate periodontal conditions over time. GFR retainers showed unacceptably high failure rates in comparison with multistranded retainers (51 versus 12 per cent). The most significant periodontal conditions were found in patients with GFR retainers with no significant differences between the GFR500 and the GFR1000 group for any parameter at any time point. Subjects without retainers showed significantly lower levels of gingival inflammation and plaque accumulation when compared with patients in any retainer group. Multistranded retainers should remain the gold standard for orthodontic retention, although periodontal complications are common. The use of GFR retainers should be discouraged in daily practice.

  15. Effect of QMix irrigant on bond strength of glass fibre posts to root dentine.

    PubMed

    Elnaghy, A M

    2014-03-01

    To investigate the effect of QMix irrigant compared with several other irrigating solutions on the bond strength of glass fibre posts to root dentine and on smear layer removal after post space preparation. One hundred and fifty single-rooted teeth were used. The specimens were divided into six groups in each test according to the irrigation regimen used: group 1, distilled water; group 2, 5.25% sodium hypochlorite (NaOCl); group 3, 2% chlorhexidine digluconate (CHX); group 4, 17% ethylenediaminetetraacetic acid (EDTA); group 5, 17% EDTA followed by 2% CHX; and group 6, QMix. Dual-cure self-adhesive resin cement (i CEM; Heraeus Kulzer, Hanau, Germany) was used for testing the adhesion of glass fibre post (Reblida; VOCO, Cuxhaven, Germany) to root dentine using a micropush-out test. Debonding specimens were examined with a scanning electron microscope. Scanning electron microscopy was also used to examine and score the treated specimens for debris removal and dentinal tubule opening. Micropush-out data were analysed using anova and Tukey's test. Debris and dentinal tubule opening scores were analysed with the Kruskal-Wallis and Mann-Whitney U-tests. QMix and 17% EDTA/2% CHX demonstrated the highest mean bond strength values in all root levels amongst the groups. Most failure modes were adhesive type of failures between post and luting material (42.6%). QMix, 17% EDTA and 17% EDTA/2% CHX performed significantly better than the other groups on smear layer removal and dentinal tubule opening. QMix is an effective irrigant that can remove smear layer, open dentinal tubules and simplify the irrigation protocol, without compromising the bonding strength of glass fibre posts cemented with a self-adhesive resin cement to root dentine. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  16. Controlling X-ray beam trajectory with a flexible hollow glass fibre

    PubMed Central

    Tanaka, Yoshihito; Nakatani, Takashi; Onitsuka, Rena; Sawada, Kei; Takahashi, Isao

    2014-01-01

    A metre-length flexible hollow glass fibre with 20 µm-bore and 1.5 mm-cladding diameters for transporting a synchrotron X-ray beam and controlling the trajectory has been examined. The large cladding diameter maintains a moderate curvature to satisfy the shallow glancing angle of total reflection. The observed transmission efficiency was more than 20% at 12.4 keV. As a demonstration, a wide-area scan of a synchrotron radiation beam was performed to identify the elements for a fixed metal film through its absorption spectra. PMID:24365917

  17. Controlling X-ray beam trajectory with a flexible hollow glass fibre.

    PubMed

    Tanaka, Yoshihito; Nakatani, Takashi; Onitsuka, Rena; Sawada, Kei; Takahashi, Isao

    2014-01-01

    A metre-length flexible hollow glass fibre with 20 µm-bore and 1.5 mm-cladding diameters for transporting a synchrotron X-ray beam and controlling the trajectory has been examined. The large cladding diameter maintains a moderate curvature to satisfy the shallow glancing angle of total reflection. The observed transmission efficiency was more than 20% at 12.4 keV. As a demonstration, a wide-area scan of a synchrotron radiation beam was performed to identify the elements for a fixed metal film through its absorption spectra.

  18. Evaluation of the flexural strength and elastic modulus of resins used for temporary restorations reinforced with particulate glass fibre.

    PubMed

    Orsi, Iara Augusta; Soares, Rodrigo Gonçalves; Villabona, Camilo Andrés; Panzeri, Heitor

    2012-06-01

    The flexural strength and the elastic modulus of acrylic resins, Dencor, Duralay and Trim Plus II, were evaluated with and without the addition of silanised glass fibre. To evaluate the flexural strength and elastic modulus, 60 test specimens were fabricated with the addition of 10% ground silanised glass fibres for the experimental group, and 60 without the incorporation of fibres, for the control group, with 20 test specimens being made of each commercial brand of resin (Dencor, Duralay and Trim Plus II) for the control group and experimental group. After the test specimens had been completed, the flexural strength and elastic modulus tests were performed in a universal testing device, using the three-point bending test. For the specimens without fibres the One-Way Analysis of Variance and the complementary Tukey test were used, and for those with fibres it was not normal, so that the non-parametric Mann-Whitney test was applied. For the flexural strength test, there was no statistical difference (p > 0.05) between each commercial brand of resin without fibres [Duralay 84.32(±8.54), Trim plus 85.39(±6.74), Dencor 96.70(±6.52)] and with fibres (Duralay 87.18, Trim plus 88.33, Dencor 98.10). However, for the elastic modulus, there was statistical difference (p > 0.01) between each commercial brand of resin without fibres [Duralay 2380.64 (±168.60), Trim plus 2740.37(±311.74), Dencor 2595.42(±261.22)] and with fibres (Duralay 3750.42, Trim plus 3188.80, Dencor 3400.75). The result showed that the incorporation of fibre did not interfere in the flexural strength values, but it increased the values for the elastic modulus. © 2010 The Gerodontology Society and John Wiley & Sons A/S.

  19. Weight loss, ion release and initial mechanical properties of a binary calcium phosphate glass fibre/PCL composite.

    PubMed

    Ahmed, I; Parsons, A J; Palmer, G; Knowles, J C; Walker, G S; Rudd, C D

    2008-09-01

    Composites comprising a biodegradable polymeric matrix and a bioactive filler show considerable promise in the field of regenerative medicine, and could potentially serve as degradable bone fracture fixation devices, depending on the properties obtained. Therefore, glass fibres from a binary calcium phosphate (50P(2)O(5)+50CaO) glass were used to reinforce polycaprolactone, at two different volume fractions (V(f)). As-drawn, non-treated and heat-treated fibres were assessed. Weight loss, ion release and the initial mechanical properties of the fibres and composites produced have been investigated. Single fibre tensile testing revealed a fibre strength of 474MPa and a tensile modulus of 44GPa. Weibull analysis suggested a scale value of 524. The composites yielded flexural strength and modulus of up to 30MPa and 2.5GPa, respectively. These values are comparable with human trabecular bone. An 8% mass loss was seen for the lower V(f) composite, whereas for the two higher V(f) composites an approximate 20% mass loss was observed over the course of the 5week study. A plateau in the degradation profile at 350h indicated that fibre dissolution was complete at this interval. This assertion was further supported via ion release studies. The leaching of fibres from the composite created a porous structure, including continuous channels within the polymer matrix. This offers further scope for tailoring scaffold development, as cells from the surrounding tissue may be induced to migrate into the resulting porous matrix.

  20. Controlled synthesis of hierarchical TiO2 nanoparticles on glass fibres and their photocatalytic performance.

    PubMed

    Chen, Lin; Yang, Sudong; Mäder, Edith; Ma, Peng-Cheng

    2014-09-07

    This paper reports the synthesis of novel photocatalysts consisting of TiO2 nanoparticles and glass fibres (GF) using a two-step process. The method involves the hydrolysis of titanium tetrachloride in the presence of GF and a following hydrothermal process under alkaline conditions. Various techniques are employed to characterize the morphology, structure and crystallinity of TiO2 on the fibre surface. The results show that depending on the experiment setups, TiO2 nanoparticles exhibit spherical or flake-like morphology, forming characteristic hierarchical structures along with flexible GF. Flake-like TiO2/GF exhibits much enhanced photocatalytic activity thanks to the large surface area and the hetero-junction of anatase and TiO2-B phases observed in its structure. An interesting observation is that the alkali treatment of GF leads to the formation of porous structures on the fibre surface, facilitating the adsorption-concentration-promoted photocatalytic process. The removal ratio of the organic dye by employing TiO2/GF remains more than 80% after six cyclic runs, showing the reusability of photocatalysts in real application. The novelty of this work lies in the synergy arising from materials with unique morphologies, structures and availabilities as well as capabilities in separating photogenerated electron-hole pairs, which have not been specifically considered previously in photocatalytic semiconductors.

  1. Silicon-core glass fibres as microwire radial-junction solar cells

    PubMed Central

    Martinsen, F. A.; Smeltzer, B. K.; Nord, M.; Hawkins, T.; Ballato, J.; Gibson, U. J.

    2014-01-01

    Vertically aligned radial-junction solar cell designs offer potential improvements over planar geometries, as carrier generation occurs close to the junction for all absorption depths, but most production methods still require a single crystal substrate. Here, we report on the fabrication of such solar cells from polycrystalline, low purity (99.98%) p-type silicon starting material, formed into silicon core, silica sheath fibres using bulk glass draw techniques. Short segments were cut from the fibres, and the silica was etched from one side, which exposed the core and formed a conical cavity around it. We then used vapour deposition techniques to create p-i-n junction solar cells. Prototype cells formed from single fibres have shown conversion efficiencies up to 3.6%, despite the low purity of the starting material. This fabrication method has the potential to reduce the energy cost and the silicon volume required for solar cell production. Simulations were performed to investigate the potential of the conical cavity around the silicon core for light collection. Absorption of over 90% of the incident light was predicted, over a wide range of wavelengths, using these structures in combination with a 10% volume fraction of silicon. PMID:25187060

  2. Silicon-core glass fibres as microwire radial-junction solar cells.

    PubMed

    Martinsen, F A; Smeltzer, B K; Nord, M; Hawkins, T; Ballato, J; Gibson, U J

    2014-09-04

    Vertically aligned radial-junction solar cell designs offer potential improvements over planar geometries, as carrier generation occurs close to the junction for all absorption depths, but most production methods still require a single crystal substrate. Here, we report on the fabrication of such solar cells from polycrystalline, low purity (99.98%) p-type silicon starting material, formed into silicon core, silica sheath fibres using bulk glass draw techniques. Short segments were cut from the fibres, and the silica was etched from one side, which exposed the core and formed a conical cavity around it. We then used vapour deposition techniques to create p-i-n junction solar cells. Prototype cells formed from single fibres have shown conversion efficiencies up to 3.6%, despite the low purity of the starting material. This fabrication method has the potential to reduce the energy cost and the silicon volume required for solar cell production. Simulations were performed to investigate the potential of the conical cavity around the silicon core for light collection. Absorption of over 90% of the incident light was predicted, over a wide range of wavelengths, using these structures in combination with a 10% volume fraction of silicon.

  3. Bioresorbable screws reinforced with phosphate glass fibre: manufacturing and mechanical property characterisation.

    PubMed

    Felfel, R M; Ahmed, I; Parsons, A J; Rudd, C D

    2013-01-01

    Use of bioresorbable screws could eliminate disadvantages associated with metals such as removal operations, corrosion, MRI interference and stress shielding. Mechanical properties of bioresorbable polymers alone are insufficient for load bearing applications application as screws. Thus, reinforcement is necessary to try and match or surpass the mechanical properties of cortical bone. Phosphate based glass fibres were used to reinforce polylactic acid (PLA) in order to produce unidirectionally aligned (UD) and unidirectionally plus randomly distributed (UD/RM) composite screws (P40 UD and P40 UD/RM). The maximum flexural and push-out properties for the composite screws (P40 UD and P40 UD/RM) increased by almost 100% in comparison with the PLA screws. While the pull-out strength and stiffness of the headless composite screws were ∼80% (strength) and ∼130% (stiffness) higher than for PLA, those with heads exhibited properties lower than those for PLA alone as a result of failure at the heads. An increase in the maximum shear load and stiffness for the composite screws (∼30% and ∼40%) in comparison to the PLA screws was also seen. Maximum torque for the PLA screws was ∼1000 mN m, while that for the composite screws were slightly lower. The SEM micrographs for P40 UD and P40 UD/RM screws revealed small gaps around the fibres, which were suggested to be due to buckling of the UD fibres during the manufacturing process. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Helical core optical fibre made of Nd3+/Yb3+-doped oxyfluoride silicate glass

    NASA Astrophysics Data System (ADS)

    Dorosz, D.; Kochanowicz, M.; Zmojda, J.; Dorosz, J.

    2010-05-01

    The properties of helical-core optical fibre made by authors from Nd3+/Yb3+-doped oxyfluoride silicate glass are presented. The construction and forming conditions of the helical-core optical fibre enabled to obtain the helix pitch from several mm and the off-set ranging from 10 μm to 200 μm. The paper also presents optimisation of Nd3+/Yb3+ ratio to enhance the emission bandwidth at 1 μm. In consequence of matching the values of the emission cross-section σem(Nd)and the absorption cross-section σabs(Yb) in the glass doped with 0.15Nd3+:0.45Yb3+ a broad (Δλ = 100nm) luminescence band in the vicinity of 1μm was obtained, which was the result of overlapping emission transitions: 2F5/2-->2F7/2 in ytterbium and 4F3/2-->4I11/2 in neodymium.

  5. Impregnation of glass fibres with polymethylmethacrylate using a powder-coating method

    NASA Astrophysics Data System (ADS)

    Vallittu, Pekka K.

    1995-01-01

    The aim of this study was to evaluate the usefulness of a powder-coating method to impregnate glass fibres with polymethylmethacrylate (PMMA) for dental purposes. The continuous unidirectional E-glass fibres, the surface of which had been treated with precured silane, were powder-coated with spherical PMMA particles. Before the powder-coated prepregs were used, the incorporated PMMA powder was dissolved with methylmethacrylate monomer. The degree of impregnation of the polymerized composite was determined with a scanning electron microscope. The results revealed that the mean degree of impregnation varied from 0.87 to 0.92, being lower in the heat-cured PMMA group (which simulated fabrication of a new denture), and higher in the autopolymerizing group (which simulated the repair of a fractured denture). The means between the two groups did not, however, differ significantly ( p=0.249). The results suggest that, even though the method has some shortcomings in terms of dental laboratory technology, the powder-coating method can be used to fabricate or repair acrylic resin-based dentures.

  6. Structuring of glass fibre surfaces by laser-induced front side etching

    NASA Astrophysics Data System (ADS)

    Lorenz, Pierre; Ehrhardt, Martin; Zimmer, Klaus

    2014-05-01

    The fabrication of sub-μm structures on glass fibre surfaces poses a big challenge for the laser processing. However, the laser-induced front side etching (LIFE) method has a great potential for the fast, nm-precision, and cost-effective production of surface structures. LIFE is a method for laser etching of transparent materials using thin absorber layers with a high absorption coefficient like metal layers. The LIFE process of the front surface of a fused silica wafer as well as of a glass fibre is studied in dependence on the laser parameters. A KrF excimer laser with a wavelength of 248 nm and a pulse duration of 25 ns was used. The resultant structures were analysed with microscopic methods (white light interferometry, scanning electron microscopy (SEM)). The analysing of the surface structures presented that the LIFE methods allow the fabrication of well-defined periodic sub-μm structures. Furthermore, the structuring process was simulated by a thermodynamic equation including an approach of the laser-plasma interaction. The theoretically predicted results presented a good agreement with the experimental results.

  7. Phosphate glass fibres promote neurite outgrowth and early regeneration in a peripheral nerve injury model.

    PubMed

    Kim, Young-Phil; Lee, Gil-Su; Kim, Jong-Wan; Kim, Min Soo; Ahn, Hong-Sun; Lim, Jae-Young; Kim, Hae-Won; Son, Young-Jin; Knowles, Jonathan C; Hyun, Jung Keun

    2015-03-01

    Three-dimensional (3D) scaffolds, which are bioactive and aid in neuronal guidance, are essential in the repair and regeneration of injured peripheral nerves. In this study, we used novel inorganic microfibres guided by phosphate glass (PG). PG fibres (PGfs) were aligned on compressed collagen that was rolled into a nerve conduit. In vitro tests confirmed that adult dorsal root ganglion (DRG) neurons showed active neurite outgrowth along the fibres, with a maximum number and length of neurites being significantly higher than those cultured on tissue culture plastic. In vivo experiments with nerve conduits that either contained PGfs (PGf/Col) or lacked them (Col) were conducted on transected sciatic nerves of rats for up to 12 weeks. One week after implantation, the PGf/Col group showed many axons extending along the scaffold, whereas the Col group showed none. Eight weeks after implantation, the PGf/Col group exhibited greater recovery of plantar muscle atrophy than the Col group. Electrophysiological studies revealed that some animals in the PGf/Col group at 6 and 7 weeks post-implantation (5.3% and 15.8%, respectively) showed compound muscle action potential. The Col group over the same period showed no response. Motor function also showed faster recovery in the PGf/Col group compared to the Col group up to 7 weeks. However, there was no significant difference in the number of axons, muscle atrophy or motor and sensory functions between the two groups at 12 weeks post-implantation. In summary, phosphate glass fibres can promote directional growth of axons in cases of peripheral nerve injury by acting as physical guides. Copyright © 2012 John Wiley & Sons, Ltd.

  8. Finite element modelling of the flexural performance of resorbable phosphate glass fibre reinforced PLA composite bone plates.

    PubMed

    Harper, L T; Ahmed, I; Felfel, R M; Qian, C

    2012-11-01

    A finite element method is presented to predict the flexural properties of resorbable phosphate glass fibre reinforced PLA composite bone plates. A novel method for meshing discontinuous fibre architectures is presented, which removes many of the limitations imposed by conventional finite element approaches. The model is used to understand the effects of increasing the span-to-thickness ratio for different fibre architectures used for PBG/PLA composites. A span-to-thickness ratio of 16:1 is found to be appropriate for materials with randomly orientated fibres, which agrees well with the test standard. However, for highly aligned materials the model indicates that a span-to-thickness ratio of 80:1 is required, in order to minimise the effects of shear deflection. The model is validated against flexural stiffness data from the literature for a range of polymers, fibres and fibre volume fractions. Generally there is less than 10% error between the FE predictions and experimental values. The model is subsequently used to perform a parametric study to understand what material developments are required to match the properties of PGF/PLA composites to cortical bone. It is concluded that alignment of the fibre is necessary to exceed the 20 GPa target, since the current manufacturing methods limit the fibre length to ∼10 mm, which consequently restricts the flexural modulus to ∼19 GPa (at 50% volume fraction). Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Evaluation of flexural strength of resin interim restorations impregnated with various types of silane treated and untreated glass fibres

    PubMed Central

    Naveen, K.S.; Singh, J.P.; Viswambaran, M.; Dhiman, R.K.

    2015-01-01

    Background Flexural strength is an important mechanical property that determines the long-term prognosis of interim restorations. Studies are lacking regarding the effect of silanation of the various types of glass fibre impregnation on the flexural strength of resin interim restorations. Methods A customized metal die was milled to simulate the prepared abutments of a three-unit fixed dental prosthesis. A total of seventy five samples of interim fixed dental prostheses were prepared using autopolymerizing tooth colour acrylic resin. Unidirectional and woven forms of glass fibres (Stick and Stick Net), which were silane treated and untreated were used to reinforce the resin matrix. Fifteen samples were prepared for each group along with unreinforced group serving as control. The flexural strength was evaluated with universal testing machine. Results The means and standard deviations of flexural strength for different groups were 13.90 ± 2.96 (control), 61.58 ± 5.26 (unidirectional fibres), 30.89 ± 3.60 (woven fibres), 112.05 ± 5.51 (silane treated unidirectional fibres) and 73.85 ± 4.10 (silane treated woven fibres) respectively. The mean flexural strength of silane treated unidirectional fibres (112.05 MPa) was highest and statistically highly significant (P < 0.0001) compared to all other groups. Conclusions Within the limitations of the current study, flexural strength of the reinforced PMMA interim fixed dental prosthesis was significantly higher (P < 0.0001) when compared to the unreinforced PMMA interim fixed dental prosthesis. The use of silane treated unidirectional glass fibres is an effective method of reinforcing interim fixed restorations made of PMMA resins. PMID:26843742

  10. Residual monomers released from glass-fibre-reinforced composite photopolymerised in contact with bone and blood.

    PubMed

    Tuusa, Sari M-R; Puska, Mervi A; Lassila, Lippo V J; Vallittu, Pekka K

    2005-01-01

    The aim of this study was to determine the quantity of residual monomers of glass fibre-reinforced composite released into water from the composite that had been photopolymerized in contact with bone and blood. E-glass fibre reinforced composite (FRC) made of E-glass fibre veil and the bis-GMA-TEGDMA-PMMA resin system was used in the study. In the first group, pieces of non-polymerised FRC were photopolymerised (40 s) in air which influenced the oxygen inhibited resin layer (positive control). In the second group, the FRC was polymerized between two glass plates allowing both surfaces to be well polymerized (negative control). In the test groups, the FRC was polymerized in contact with bone or in contact with blood. FRC specimens from all four groups were incubated in three milliliters of deionised water at 37 degrees C for three days. At the end of the incubation period, the residual monomers were extracted from the water with dichloromethane, and the residual monomers of TEGDMA and bis-GMA quantitatively analysed by HPLC. The degree of monomer conversion was measured by FTIR from the surface of the test specimen. Differences between the groups were analysed using one-way ANOVA (p < 0.05). The total quantity of residual monomers released from FRC polymerized in contact with bone was lower (0.55 wt%) than in the positive control group (0.97 wt%) (p = 0.021), and only slightly exceeded that of the negative control group (0.42 wt%) (p = 0.717). The total quantity of monomers released from FRC polymerized in contact with blood was at the level of the negative control group. The main residual monomer released was TEGDMA. The surfaces of the positive and negative controls showed a clear difference between the degree of monomer conversion, 34.0 and 62.8%, respectively, when analysed with FTIR (p < 0.001). The surface of the bone or contact with blood did not significantly inhibit the photoinitiated free radical polymerisation of the dimethacrylate monomer system of the

  11. Fracture toughness, compressive strength and load-bearing capacity of short glass fibre-reinforced composite resin.

    PubMed

    Garoushi, Sufyan; Vallittu, Pekka K; Lassila, Lippo V

    2011-01-01

    To investigate the reinforcing effect of short E-glass fibre fillers on fracture related mechanical properties of dental composite resin with a semi-interpenetrating polymer network (IPN) polymer matrix. Experimental short fibre composite (FC) resin was prepared by mixing 22.5 wt% of short E-glass fibres, 22.5 wt% of IPN-resin and 55 wt% of silane treated silica fillers using a high speed mixing machine. Test specimens were made bar shaped (3 × 6 × 25 mm3), cylindrical (6 mm length × 3 mm diameter) and cubic (9.5 × 5.5 × 3 mm3) from the experimental FC resin and conventional particulate composite resin (Grandio) as control. The test specimens (n = 8) were either dry stored or water stored (37°C for 30 days) before the mechanical tests. A three-point loading test and compression test were carried out according to ISO 10477 and a static loading test was carried out using a steel ball (Ø 3.0 mm) with a speed of 1.0 mm/min until fracture. Experimental fibre composite had a significantly higher mechanical performance for fracture toughness (14 MNm-1.5), compression strength (129 MPa) and static load-bearing capacity (1584 N) than the control composite (2 MNm-1.5, 112 MPa and 1031 N). The resin with short E-glass fibre fillers and IPN-polymer matrix yielded improved mechanical performance compared to the conventional particulate composite resin.

  12. Calcium fluxes in single muscle fibres measured with a glass scintillator probe.

    PubMed Central

    Ashley, C C; Lea, T J

    1978-01-01

    1. An intracellular glass scintillator (Caldwell & Lea, 1973) has been used to obtain a continuous record of the influx of 45Ca into single muscle fibres of the barnacle, Balanus nubilus. 2. In the presence of intracellular EGTA (final concentration greater than 3 mM/kg), the scintillator detected an initial fast phase to the influx (half-time = 18.3 min, compartment size = 4.1% fibre volume) followed by a slow, linear phase which gave a value for the Ca influx of 1.2 p-mole . cm-2 . sec-1. The efflux of 45Ca was also measured with the scintillator by transferring a 45Ca-loaded fibre into 45Ca-free saline. Two exponential phases of efflux were detected with half-times of 16.2 and 500 min. 3. The characterisitics of the fast phase of the influx and efflux are similar to those of the influx of the impermeant sucrose and inulin, suggesting that the fast phase represents exchange with the extracellular 'cleft space'. This phase was insensitive to external La3+ (2 mM). 4. The slow phase is considered to represent the flux of Ca across the surface membrane. It was inhibited by external La3+ (2 mM) and stimulated by replacing external Na+ with Li+. 5. When EGTA-injected fibres were depolarized using an axial, intracellular electrode the Ca influx, measured from the slow phase, was increased. At higher concentrations of intracellular EGTA (6--22 mM/kg), the extra Ca influx due to a rectangular, depolarizing current pulse was proportional to the number of Ca spikes it produced. A single Ca spike gave an extra Ca influx of 19--48 p-mole . cm-2. External D600 (5 x 10(-4)M) inhibited both Ca spike and the extra Ca influx. 6. At lower intracellular EGTA concentrations (3.6--11 mM/kg), a 50 mV depolarization of 250 msec duration gave a mean extra Ca influx of 80 p-mole . cm-2. The upper value was 145 p-mole . cm-2 and this would increase the total internal Ca by 4.1 micrometer/kg. It is calculated that if all this extra Ca was bound to the myofibrillar sites for tension, it

  13. Flexural strength,water sorption and solubility of a methylmethacrylate-free denture base polymer reinforced with glass fibre reinforcement.

    PubMed

    Mutluay, M M; Tezvergil-Mutluay, A; Vallittu, P; Lassila, L

    2013-12-01

    A methylmethacrylate-free denture base polymer (Eclipse) in comparison to a conventional denture base polymer (Palapress vario) was evaluated after water saturation and Stick glass fibre reinforcement. The data were analysed with ANOVA at a = 0.05. Water-storage caused a decrease in the flexural strength and stiffness of the materials (p > 0.05). Conventional denture base material with fibre reinforcement gave highest flexural strength (201.1 MPa) compared to fibre reinforced Eclipse (79.1 MPa) (p < 0.05). Water sorption after 76 days was 2.08% (Palapress vario) and 1.55% (Eclipse). Fibre-reinforcement of methylmethacrylate-free material was not as successful as conventional denture base and needs to be further optimized.

  14. Foreign body granuloma of the penis caused by occupational glass fibre exposure.

    PubMed Central

    Hinnen, U; Elsner, P; Barraud, M; Burg, G

    1997-01-01

    We report a patient who presented with the suspected diagnosis of syphilis. Clinical findings included a penile ulcer, positive history of syphilis more than 20 years ago, and positive syphilis serology (TPHA, FTA-Abs). A biopsy showed a plasma-cell rich inflammation with granuloma formation. Since a birefractory structure was observed in the biopsy possibly corresponding to a foreign body, the patient's occupational exposure was investigated. Working in the fiber reinforced plastics industry, he was heavily exposed to glass fibre that was even detected on the inside of his underwear. Taking the serological pattern into account that was not consistent with active syphilis, a penile ulcer following a foreign body reaction was diagnosed. This case report demonstrates the difficulties of differentiating foreign body granuloma of the genital region from venereal diseases with granuloma formation. Images PMID:9582491

  15. Mechanical behaviour of glass fibre reinforced composite at varying strain rates

    NASA Astrophysics Data System (ADS)

    Acharya, Saikat; Mondal, D. K.; Ghosh, K. S.; Mukhopadhyay, A. K.

    2017-03-01

    Here we report the results of compressive split Hopkinson pressure bar experiments (SHPB) conducted on unidirectional glass fibre reinforced polymer (GFRP) in the strain rate regime 5  ×  102–1.3  ×  103 s‑1. The maximum compressive strength of GFRP was found to increase by as much as 55% with increase in strain rate. However, the corresponding relative strain to failure response was measured to increase only marginally with increase in strain rates. Based on the experimental results and photomicrographs obtained from FE-SEM based post mortem examinations, the failure phenomena are suggested to be associated with increase in absorption of energy from low to high strain rates. Attempts have been made to explain these observations in terms of changes in deformation mechanisms primarily as a function of strain rates.

  16. Fatigue Behaviour of Glass Fibre Reinforced Composites for Ocean Energy Conversion Systems

    NASA Astrophysics Data System (ADS)

    Boisseau, A.; Davies, P.; Thiebaud, F.

    2013-04-01

    The development of ocean energy conversion systems places more severe requirements on materials than similar land-based structures such as wind turbines. Intervention and maintenance at sea are very costly, so for ocean energy supply to become economically viable long term durability must be guaranteed. Cyclic loading is a common feature of most energy conversion devices and composites are widely used, but few data are available concerning the fatigue behaviour in sea water of composite materials. This paper presents the results from an experimental study to fill this gap. The fatigue behavior of composite materials reinforced with different types of glass fibre is characterized in air and in sea water; the influence of testing in sea water rather than air is shown to be small. However, sea water ageing is shown to reduce the fatigue lifetime significantly and strongly depends on matrix formulation.

  17. A homogeneous microwave curing process for epoxy/glass fibre composites

    SciTech Connect

    Outifa, L.; Delmotte, M.; Jullien, H.

    1995-12-01

    A global model is established which describes a successful process for an optimised and homogeneous curing of large epoxy/glass fibre composite pieces. The process is characterised by a strong coupling between dielectric chemical and thermal aspects. It appears that the use of a single mode travelling continuous wave is necessary to obtain a homogeneous distribution of the electric field. Dielectric properties of matched transitions and of moulds are selected to focus the energy inside the material to cure. A thermal model describes the energy transfers related to chemical and dielectric heat sources and their variations during processing. The whole model is founded on general considerations and equations and therefore can be extended to many other configurations.

  18. Optimization of Tensile Process Parameters of Bi-Axial Glass Fibre Reinforced Epoxycomposite Using Taguchi Method

    NASA Astrophysics Data System (ADS)

    Priya, I. Infanta Mary; Vinayagam, B. K.

    2017-05-01

    The aim of this work is to optimize the parameters namely load, elongation and thickness in tensile test of glass fibre reinforced polymer(GFRP) composites. In the present work, experiments were carried out as per the Taguchi experimental design and an L9 orthogonal array was used to study the influence of various combinations of parameters on stress and strain factors of the composite using MINITAB 17. Analysis of variance (ANOVA) test was conducted to determine the significance of each parameter on stress and strain value of the composite. The results indicate thatload is the most significant factor influencing the stress, and also it is the most significant factor inducing the strain of the composite. This work is useful in selecting the optimum values of various parameters that would, not only maximize the stress in the composite but also reduces the strain to a minimum level and improve the strength of the composite by acquiring a higher load bearing capacity.

  19. Investigation of Creep Rupture Phenomenon in Glass Fibre Reinforced Polymer (GFRP) Stirrups

    NASA Astrophysics Data System (ADS)

    Johal, Kanwardeep Singh

    Glass Fibre-Reinforced Polymer (GFRP) bars offer a feasible alternative to typical steel reinforcement in concrete structures where there are concerns of corrosion or magnetic interference. In order to design safe structures for a service life of 50 to 100 years, the long-term material properties of GFRP must be understood. Thirty GFRP stirrups of three types were tested under sustained loading to investigate creep rupture and modulus degradation behaviour. The time to failure under varying sustained loads was used to extrapolate the safe design load for typical service lives. It was found that shear critical beams with shear reinforcement designed in accordance with CSA-S806 and ACI-440 provisions may be at risk of premature failure under sustained design loads. Analysis was based on finite element modelling and previously tested beams. Additionally, no moduli degradation was observed in this study. A cumulative weakening model was developed to potentially take into account fatigue loading.

  20. Optimization of woven jute/glass fibre-reinforced polyester hybrid composite solar parabolic trough collector

    NASA Astrophysics Data System (ADS)

    Reddy, K. S.; Singla, Hitesh

    2017-07-01

    In the present work, structural analysis of 5.77m × 4m woven jute (J)/glass (G) fibre-reinforced polyester hybrid composite solar parabolic trough is carried out based on trough parameters to obtain the minimum RMS local slope deviation, termed as SDx value under gravity loading. The optimization is done by varying parameters viz. direction and size of reinforced conduits, stacking number and sequence of hybrid trough laminate at fibre orientation of Δθ=45° and Δθ=60° amongst the layers at 0° collector angle. The analysis revealed that the configuration in which the conduits are placed in both X and Y directions is preferred over other configurations to scale down the effect of wind loads. Furthermore it has been observed that laminate of the order [0°G/45°G/-45°J/90°J]s undergoes minimum surface deformation amongst all the other configurations at conduit reinforcement in both X and Y directions for a conduit thickness of 0.75 mm and radius of 10 mm and obtains the overall SDx value of 1.3492 mrad. The results shows that proposed trough model is very promising and evolves a cost effective system.

  1. Influence of silane and solvated bonding agents on the bond strength to glass-fibre posts.

    PubMed

    Oliveira, Aline S; Ramalho, Elisa S; Spazzin, Aloísio O; Naves, Lucas Z; Moraes, Rafael R

    2013-12-01

    The combined use of silane and solvated bonding agents on the bond strength to glass-fibre posts was investigated. A model Bis-GMA/HEMA adhesive was formulated with no solvent, 30% of ethanol or 80% of acetone. The surfaces of rectangular-shaped posts were silanated or not and one of the agents was applied, except for the control group. Cylinders of resin cement (RelyX ARC, 3M ESPE, Saint Paul, MN, USA) were built-up on the surfaces (n = 20) and submitted to shear testing. All groups showed higher bond strengths when the surfaces were silanated. When no silanization was carried out, the use of bonding agents, either solvated or non-solvated, increased the bond strengths. All groups treated with both silane and bonding agent showed higher bond strengths than the group that was only silanated. Control and ethanol-based adhesives were similar, whereas the acetone-based agent yielded higher bond strengths. Adhesive failures were predominant. Combination of silane and adhesive enhanced the bond to fibre posts.

  2. Polymeric gel electrolytes reinforced with glass-fibre cloth for lithium secondary batteries

    NASA Astrophysics Data System (ADS)

    Park, Ho Cheol; Chun, Jong Han; Kim, Sang Hern; Ko, Jang Myoun; Jo, Soo Ik; Chung, Jae Sik; Sohn, Hun-Joon

    Polymeric gel electrolytes (PGE), based on polyacrylonitrile blended with poly(vinylidene fluoride-co-hexafluoropropylene) (P(VdF-co-HFP)), which are reinforced with glass-fibre cloth (GFC) to increase the mechanical strength, are prepared for the practical use in lithium secondary batteries. The resulting electrolytes exhibit electrochemical stability at 4.5 V against lithium metal and a conductivity value of (2.0-2.1)×10 -3 S cm -1 at room temperature. The GFC-PGE electrolytes show excellent strength and flexibility when used in batteries even if they contain a plasticiser. A test cell with LiCoO 2 as a positive electrode and mesophase pich-based carbon fibre (MCF) as a negative electrode display a capacity of 110 mAh g -1 based on the positive electrode weight at the 0.2 C rate at room temperature. Over 80% of the initial capacity is retained after 400 cycles. This indicates that GFC is suitable as a reinforcing material to increase the mechanical strength of gel-based electrolytes for lithium secondary batteries.

  3. Monitoring chemical degradation of thermally cycled glass-fibre composites using hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Papadakis, V. M.; Müller, B.; Hagenbeek, M.; Sinke, J.; Groves, R. M.

    2016-04-01

    Nowadays, the application of glass-fibre composites in light-weight structures is growing. Although mechanical characterizations of those structures are commonly performed in testing, chemical changes of materials under stresses have not yet been well documented. In the present work coupon tests and Hyperspectral Imaging (HSI) have been used to categorise possible chemical changes of glass-fibre reinforced polymers (GFRP) which are currently used in the aircraft industry. HSI is a hybrid technique that combines spectroscopy with imaging. It is able to detect chemical degradation of surfaces and has already been successfully applied in a wide range of fields including astronomy, remote sensing, cultural heritage and medical sciences. GFRP specimens were exposed to two different thermal loading conditions. One thermal loading condition was a continuous thermal exposure at 120°C for 24h, 48 h and 96h, i.e. ageing at a constant temperature. The other thermal loading condition was thermal cycling with three different numbers of cycles (4000, 8000, 12000) and two temperature ranges (0°C to 120°C and -25°C to 95°C). The effects of both conditions were measured using both HSI and interlaminar shear (ILSS) tests. No significant changes of the physical properties of the thermally cycled GFRP specimens were detected using interlaminar shear strength tests and optical microscopy. However, when using HIS, differences of the surface conditions were detected. The results showed that the different thermal loading conditions could be successfully clustered in different colours, using the HSI linear unmixing technique. Each different thermal loading condition showed a different chemical degradation level on its surface which was indicated using different colours.

  4. Influence of post pattern and resin cement curing mode on the retention of glass fibre posts.

    PubMed

    Poskus, L T; Sgura, R; Paragó, F E M; Silva, E M; Guimarães, J G A

    2010-04-01

    To evaluate the influence of post design and roughness and cement system (dual- or self-cured) on the retention of glass fibre posts. Two tapered and smooth posts (Exacto Cônico No. 2 and White Post No. 1) and two parallel-sided and serrated posts (Fibrekor 1.25 mm and Reforpost No. 2) were adhesively luted with two different resin cements--a dual-cured (Rely-X ARC) and a self-cured (Cement Post)--in 40 single-rooted teeth. The teeth were divided into eight experimental groups (n = 5): PFD--Parallel-serrated-Fibrekor/dual-cured; PRD--Parallel-serrated-Reforpost/dual-cured; TED--Tapered-smooth-Exacto Cônico/dual-cured; TWD--Tapered-smooth-White Post/dual-cured; PFS--Parallel-serrated-Fibrekor/self-cured; PRS--Parallel-serrated-Reforpost/self-cured; TES--Tapered-smooth-Exacto Cônico/self-cured; TWS--Tapered-smooth-White Post/self-cured. The specimens were submitted to a pull-out test at a crosshead speed of 0.5 mm min(-1). Data were analysed using analysis of variance and Bonferroni's multiple comparison test (alpha = 0.05). Pull-out results (MPa) were: PFD = 8.13 (+/-1.71); PRD = 8.30 (+/-0.46); TED = 8.68 (+/-1.71); TWD = 9.35 (+/-1.99); PFS = 8.54 (+/-2.23); PRS = 7.09 (+/-1.96); TES = 8.27 (+/-3.92); TWS = 7.57 (+/-2.35). No statistical significant difference was detected for posts and cement factors and their interaction. The retention of glass fibre posts was not affected by post design or surface roughness nor by resin cement-curing mode. These results imply that the choice for serrated posts and self-cured cements is not related to an improvement in retention.

  5. Transverse Crack Detection in 3D Angle Interlock Glass Fibre Composites Using Acoustic Emission

    PubMed Central

    Gresil, Matthieu; Saleh, Mohamed Nasr; Soutis, Constantinos

    2016-01-01

    In addition to manufacturing cost and production rates, damage resistance has become a major issue for the composites industry. Three-dimensional (3D) woven composites have superior through-thickness properties compared to two-dimensional (2D) laminates, for example, improved impact damage resistance, high interlaminar fracture toughness and reduced notch sensitivity. The performance of 3D woven preforms is dependent on the fabric architecture, which is determined by the binding pattern. For this study, angle interlock (AI) structures with through-thickness binding were manufactured. The AI cracking simulation shows that the transverse component is the one that leads to transverse matrix cracking in the weft yarn under tensile loading. Monitoring of acoustic emission (AE) during mechanical loading is an effective tool in the study of damage processes in glass fiber-reinforced composites. Tests were performed with piezoelectric sensors bonded on a tensile specimen acting as passive receivers of AE signals. An experimental data has been generated which was useful to validate the multi-physics finite element method (MP-FEM), providing insight into the damage behaviour of novel 3D AI glass fibre composites. MP-FEM and experimental data showed that transverse crack generated a predominant flexural mode A0 and also a less energetic extensional mode S0. PMID:28773821

  6. Transverse Crack Detection in 3D Angle Interlock Glass Fibre Composites Using Acoustic Emission.

    PubMed

    Gresil, Matthieu; Saleh, Mohamed Nasr; Soutis, Constantinos

    2016-08-16

    In addition to manufacturing cost and production rates, damage resistance has become a major issue for the composites industry. Three-dimensional (3D) woven composites have superior through-thickness properties compared to two-dimensional (2D) laminates, for example, improved impact damage resistance, high interlaminar fracture toughness and reduced notch sensitivity. The performance of 3D woven preforms is dependent on the fabric architecture, which is determined by the binding pattern. For this study, angle interlock (AI) structures with through-thickness binding were manufactured. The AI cracking simulation shows that the transverse component is the one that leads to transverse matrix cracking in the weft yarn under tensile loading. Monitoring of acoustic emission (AE) during mechanical loading is an effective tool in the study of damage processes in glass fiber-reinforced composites. Tests were performed with piezoelectric sensors bonded on a tensile specimen acting as passive receivers of AE signals. An experimental data has been generated which was useful to validate the multi-physics finite element method (MP-FEM), providing insight into the damage behaviour of novel 3D AI glass fibre composites. MP-FEM and experimental data showed that transverse crack generated a predominant flexural mode A0 and also a less energetic extensional mode S0.

  7. Radio frequency shielding behaviour of silane treated Fe2O3/E-glass fibre reinforced epoxy hybrid composite

    NASA Astrophysics Data System (ADS)

    Arun prakash, V. R.; Rajadurai, A.

    2016-10-01

    In this work, radio frequency shielding behaviour of polymer (epoxy) matrixes composed of E-glass fibres and Fe2O3 fillers have been studied. The principal aim of this project is to prepare suitable shielding material for RFID application. When RFID unit is pasted on a metal plate without shielding material, the sensing distance is reduced, resulting in a less than useful RFID system. To improve RF shielding of epoxy, fibres and fillers were utilized. Magnetic behaviour of epoxy polymer composites was measured by hysteresis graphs (B-H) followed by radio frequency identifier setup. Fe2O3 particles of sizes 800, 200 and 100 nm and E-glass fibre woven mat of 600 g/m2 were used to make composites. Particle sizes of 800 nm and 200 nm were prepared by high-energy ball milling, whereas particles of 100 nm were prepared by sol-gel method. To enhance better dispersion of particles within the epoxy matrix, a surface modification process was carried out on fillers by an amino functional coupling agent called 3-Aminopropyltrimethoxysilane (APTMS). Crystalline and functional groups of siliconized Fe2O3 particles were characterized by XRD and FTIR spectroscopy analysis. Variable quantity of E-glass fibre (25, 35, and 45 vol%) was laid down along with 0.5 and 1.0 vol% of 800, 200, and 100 nm size Fe2O3 particles into the matrix, to fabricate the hybrid composites. Scanning electron microscopy and transmission electron microscopy images reveal the shape and size of Fe2O3 particles for different milling times and particle dispersion in the epoxy matrix. The maximum improved sensing distance of 45.2, 39.4 and 43.5 % was observed for low-, high-, and ultra-high radio frequency identifier setup along with shielding composite consist of epoxy, 1 vol% 200 nm Fe2O3 particles and 45 vol% of E-glass fibre.

  8. Cyclic loading of endodontically treated teeth restored with glass fibre and titanium alloy posts: fracture resistance and failure modes.

    PubMed

    Abdul Salam, Saridatun Nur; Banerjee, Avijit; Mannocci, Francesco; Pilecki, Peter; Watson, Timothy F

    2006-09-01

    The aims of this in-vitro investigation were to compare the fracture resistance and the failure modes of endodontically treated teeth restored with glass fibre-reinforced posts with those of teeth restored with titanium-alloy posts. A total of 60 single-rooted human mandibular premolars were endodontically treated. The teeth were divided into two experimental and one control group. Post spaces 9mm long were prepared in the roots of the experimental groups in which glass fibre-reinforced posts (Group A) and titanium-alloy posts (Group B) were cemented. In the control group (Group C), no post was inserted. The specimens were stored in normal saline for a period of three weeks before being intermittently loaded at an angle of 30 degrees degrees to the long axis of the tooth at a frequency of two loads of 40N per second. Log-rank test used for the overall analysis revealed that there was no significant difference of fracture resistance between teeth restored with glass fibre-reinforced posts (Group A) and titanium-alloy posts (Group B). The survival of the control group was found to be significantly inferior to that of the experimental groups. There was no significant difference in the number of failures between the two experimental groups. There was significantly more core and post failure for the glass fibre-reinforced posts, root and core failure for the titanium-alloy posts and core failure for the control group. The results suggest that post failures are more frequent in teeth restored with quartz fibre posts and root fractures are more frequent in teeth restored with titanium posts.

  9. Cytocompatibility and Mechanical Properties of Short Phosphate Glass Fibre Reinforced Polylactic Acid (PLA) Composites: Effect of Coupling Agent Mediated Interface

    PubMed Central

    Hasan, Muhammad Sami; Ahmed, Ifty; Parsons, Andrew; Walker, Gavin; Scotchford, Colin

    2012-01-01

    In this study three chemical agents Amino-propyl-triethoxy-silane (APS), sorbitol ended PLA oligomer (SPLA) and Hexamethylene diisocyanate (HDI) were identified to be used as coupling agents to react with the phosphate glass fibre (PGF) reinforcement and the polylactic acid (PLA) polymer matrix of the composite. Composites were prepared with short chopped strand fibres (l = 20 mm, ϕ = 20 µm) in a random arrangement within PLA matrix. Improved, initial composite flexural strength (~20 MPa) was observed for APS treated fibres, which was suggested to be due to enhanced bonding between the fibres and polymer matrix. Both APS and HDI treated fibres were suggested to be covalently linked with the PLA matrix. The hydrophobicity induced by these coupling agents (HDI, APS) helped to resist hydrolysis of the interface and thus retained their mechanical properties for an extended period of time as compared to non-treated control. Approximately 70% of initial strength and 65% of initial modulus was retained by HDI treated fibre composites in contrast to the control, where only ~50% of strength and modulus was retained after 28 days of immersion in PBS at 37 °C. All coupling agent treated and control composites demonstrated good cytocompatibility which was comparable to the tissue culture polystyrene (TCP) control, supporting the use of these materials as coupling agent’s within medical implant devices. PMID:24955744

  10. Effect of Si and Fe doping on calcium phosphate glass fibre reinforced polycaprolactone bone analogous composites.

    PubMed

    Mohammadi, M Shah; Ahmed, I; Muja, N; Almeida, S; Rudd, C D; Bureau, M N; Nazhat, S N

    2012-04-01

    Reinforcing biodegradable polymers with phosphate-based glass fibres (PGF) is of interest for bone repair and regeneration. In addition to increasing the mechanical properties, PGF can also release bioinorganics, as they are water soluble, a property that may be controllably translated into a fully degradable composite. Herein, the effect of Si and Fe on the solubility of calcium-containing phosphate-based glasses (PG) in the system (50P(2)O(5)-40CaO-(10-x)SiO(2)-xFe(2)O(3), where x=0, 5 and 10 mol.%) were investigated. On replacing SiO(2) with Fe(2)O(3), there was an increase in the glass transition temperature and density of the PG, suggesting greater crosslinking of the phosphate chains. This significantly reduced the dissolution rates of degradation and ion release. Two PG formulations, 50P(2)O(5)-40CaO-10Fe(2)O(3) (Fe10) and 50P(2)O(5)-40CaO-5Fe(2)O(3)-5SiO(2) (Fe5Si5), were melt drawn into fibres and randomly incorporated into polycaprolactone (PCL). Initially, the flexural strength and modulus significantly increased with PGF incorporation. In deionized water, PCL-Fe(5)Si(5) displayed a significantly greater weight loss and ion release compared with PCL-Fe10. In simulated body fluid, brushite was formed only on the surface of PCL-Fe(5)Si(5). Dynamic mechanical analysis in phosphate buffered saline (PBS) at 37°C revealed that the PCL-Fe10 storage modulus (E') was unchanged up to day 7, whereas the onset of PCL-Fe(5)Si(5)E' decrease occurred at day 4. At longer-term ageing in PBS, PCL-Fe(5)Si(5) flexural strength and modulus decreased significantly. MC3T3-E1 preosteoblasts seeded onto PCL-PGF grew up to day 7 in culture. PGF can be used to control the properties of biodegradable composites for potential application as bone fracture fixation devices.

  11. The reinforcement effect of polyethylene fibre and composite impregnated glass fibre on fracture resistance of endodontically treated teeth: An in vitro study

    PubMed Central

    Luthria, Archana; Srirekha, A; Hegde, Jayshree; Karale, Rupali; Tyagi, Sanjana; Bhaskaran, Sajeev

    2012-01-01

    Aim: The aim of this study was to evaluate the fracture resistance of endodontically treated maxillary premolars with wide mesio-occluso-distal (MOD) cavities restored with either composite resin, or composite resin reinforced with different types of fibres. Materials and Methods: Fifty human maxillary premolars were selected. Five intact teeth served as positive controls. Endodontic therapy was carried out in the remaining forty-five teeth. Standardized MOD cavities were prepared in all the teeth. The teeth were restored with a nanocomposite using an incremental technique. These forty five teeth were randomly divided into three experimental groups (Group A, B and C) (n = 15). The teeth in Group A did not undergo any further procedures. The teeth in Group B and C were reinforced with composite impregnated glass fibre and polyethylene fibre, respectively. Fracture resistance was measured in Newtons (N). Results: The positive controls showed the highest mean fracture resistance (811.90 N), followed by Group B (600.49N), Group A (516.96N) and Group C (514.64N), respectively. One Way analysis of variance (ANOVA) test revealed a statistically significant difference between all the groups (P = 0.001). Post-hoc Tukey test revealed a moderately significant difference (P = 0.034) between Control and Group B, and a strongly significant difference between Control and Group A (P = 0.002), and Control and Group C (P = 0.001). Conclusions: Endodontic therapy and MOD cavity preparation significantly reduced the fracture resistance of endodontically treated maxillary premolars (P = 0.001). No statistically significant difference was found between the experimental groups (Group A, B and C) (P > 0.1). However, the fracture resistance of the composite impregnated glass fibre reinforced group was much higher than the others. PMID:23112487

  12. The reinforcement effect of polyethylene fibre and composite impregnated glass fibre on fracture resistance of endodontically treated teeth: An in vitro study.

    PubMed

    Luthria, Archana; Srirekha, A; Hegde, Jayshree; Karale, Rupali; Tyagi, Sanjana; Bhaskaran, Sajeev

    2012-10-01

    The aim of this study was to evaluate the fracture resistance of endodontically treated maxillary premolars with wide mesio-occluso-distal (MOD) cavities restored with either composite resin, or composite resin reinforced with different types of fibres. Fifty human maxillary premolars were selected. Five intact teeth served as positive controls. Endodontic therapy was carried out in the remaining forty-five teeth. Standardized MOD cavities were prepared in all the teeth. The teeth were restored with a nanocomposite using an incremental technique. These forty five teeth were randomly divided into three experimental groups (Group A, B and C) (n = 15). The teeth in Group A did not undergo any further procedures. The teeth in Group B and C were reinforced with composite impregnated glass fibre and polyethylene fibre, respectively. Fracture resistance was measured in Newtons (N). The positive controls showed the highest mean fracture resistance (811.90 N), followed by Group B (600.49N), Group A (516.96N) and Group C (514.64N), respectively. One Way analysis of variance (ANOVA) test revealed a statistically significant difference between all the groups (P = 0.001). Post-hoc Tukey test revealed a moderately significant difference (P = 0.034) between Control and Group B, and a strongly significant difference between Control and Group A (P = 0.002), and Control and Group C (P = 0.001). Endodontic therapy and MOD cavity preparation significantly reduced the fracture resistance of endodontically treated maxillary premolars (P = 0.001). No statistically significant difference was found between the experimental groups (Group A, B and C) (P > 0.1). However, the fracture resistance of the composite impregnated glass fibre reinforced group was much higher than the others.

  13. Effect of boron oxide addition on fibre drawing, mechanical properties and dissolution behaviour of phosphate-based glass fibres with fixed 40, 45 and 50 mol% P2O5

    PubMed Central

    Sharmin, Nusrat; Parsons, Andrew J; Rudd, Chris D

    2014-01-01

    Previous studies investigating manufacture of phosphate-based glass fibres from glasses fixed with P2O5 content less than 50 mol% showed that continuous manufacture without breakage was very difficult. In this study, nine phosphate-based glass formulations from the system P2O5-CaO-Na2O-MgO-B2O3 were prepared with P2O5 contents fixed at 40, 45 and 50 mol%, where Na2O was replaced by 5 and 10 mol% B2O3 and MgO and CaO were fixed to 24 and 16 mol%, respectively. The effect of B2O3 addition on the fibre drawing, fibre mechanical properties and dissolution behaviour was investigated. It was found that addition of 5 and 10 mol% B2O3 enabled successful drawing of continuous fibres from glasses with phosphate (P2O5) contents fixed at 40, 45 and 50 mol%. The mechanical properties of the fibres were found to significantly increase with increasing B2O3 content. The highest tensile strength (1200 ± 130 MPa) was recorded for 45P2O5-16CaO-5Na2O-24MgO-10B2O3 glass fibres. The fibres were annealed, and a comparison of the mechanical properties and mode of degradation of annealed and non-annealed fibres were investigated. A decrease in tensile strength and an increase in tensile modulus were observed for the annealed fibres. An assessment of the change in mechanical properties of both the annealed and non-annealed fibres was performed in phosphate-buffered saline (PBS) at 37℃ for 28 and 60 days, respectively. Initial loss of mechanical properties due to annealing was found to be recovered with degradation. The B2O3-containing glass fibres were found to degrade at a much slower rate as compared to the non-B2O3-containing fibres. Both annealed and non-annealed fibres exhibited a peeling effect of the fibre's outer layer during degradation. PMID:24939962

  14. Effect of boron oxide addition on fibre drawing, mechanical properties and dissolution behaviour of phosphate-based glass fibres with fixed 40, 45 and 50 mol% P2O5.

    PubMed

    Sharmin, Nusrat; Parsons, Andrew J; Rudd, Chris D; Ahmed, Ifty

    2014-11-01

    Previous studies investigating manufacture of phosphate-based glass fibres from glasses fixed with P2O5 content less than 50 mol% showed that continuous manufacture without breakage was very difficult. In this study, nine phosphate-based glass formulations from the system P2O5-CaO-Na2O-MgO-B2O3 were prepared with P2O5 contents fixed at 40, 45 and 50 mol%, where Na2O was replaced by 5 and 10 mol% B2O3 and MgO and CaO were fixed to 24 and 16 mol%, respectively. The effect of B2O3 addition on the fibre drawing, fibre mechanical properties and dissolution behaviour was investigated. It was found that addition of 5 and 10 mol% B2O3 enabled successful drawing of continuous fibres from glasses with phosphate (P2O5) contents fixed at 40, 45 and 50 mol%. The mechanical properties of the fibres were found to significantly increase with increasing B2O3 content. The highest tensile strength (1200 ± 130 MPa) was recorded for 45P2O5-16CaO-5Na2O-24MgO-10B2O3 glass fibres. The fibres were annealed, and a comparison of the mechanical properties and mode of degradation of annealed and non-annealed fibres were investigated. A decrease in tensile strength and an increase in tensile modulus were observed for the annealed fibres. An assessment of the change in mechanical properties of both the annealed and non-annealed fibres was performed in phosphate-buffered saline (PBS) at 37℃ for 28 and 60 days, respectively. Initial loss of mechanical properties due to annealing was found to be recovered with degradation. The B2O3-containing glass fibres were found to degrade at a much slower rate as compared to the non-B2O3-containing fibres. Both annealed and non-annealed fibres exhibited a peeling effect of the fibre's outer layer during degradation.

  15. In-situ polymerisation of fully bioresorbable polycaprolactone/phosphate glass fibre composites: In vitro degradation and mechanical properties.

    PubMed

    Chen, Menghao; Parsons, Andrew J; Felfel, Reda M; Rudd, Christopher D; Irvine, Derek J; Ahmed, Ifty

    2016-06-01

    Fully bioresorbable composites have been investigated in order to replace metal implant plates used for hard tissue repair. Retention of the composite mechanical properties within a physiological environment has been shown to be significantly affected due to loss of the integrity of the fibre/matrix interface. This study investigated phosphate based glass fibre (PGF) reinforced polycaprolactone (PCL) composites with 20%, 35% and 50% fibre volume fractions (Vf) manufactured via an in-situ polymerisation (ISP) process and a conventional laminate stacking (LS) followed by compression moulding. Reinforcing efficiency between the LS and ISP manufacturing process was compared, and the ISP composites revealed significant improvements in mechanical properties when compared to LS composites. The degradation profiles and mechanical properties were monitored in phosphate buffered saline (PBS) at 37°C for 28 days. ISP composites revealed significantly less media uptake and mass loss (p<0.001) throughout the degradation period. The initial flexural properties of ISP composites were substantially higher (p<0.0001) than those of the LS composites, which showed that the ISP manufacturing process provided a significantly enhanced reinforcement effect than the LS process. During the degradation study, statistically higher flexural property retention profiles were also seen for the ISP composites compared to LS composites. SEM micrographs of fracture surfaces for the LS composites revealed dry fibre bundles and poor fibre dispersion with polymer rich zones, which indicated poor interfacial bonding, distribution and adhesion. In contrast, evenly distributed fibres without dry fibre bundles or polymer rich zones, were clearly observed for the ISP composite samples, which showed that a superior fibre/matrix interface was achieved with highly improved adhesion.

  16. Glass Fibre-Reinforced Composite Post and Core Used in Decayed Primary Anterior Teeth: A Case Report

    PubMed Central

    Verma, Leena; Passi, Sidhi

    2011-01-01

    Aesthetic requirement of severely mutilated primary anterior teeth in the case of early childhood caries has been a challenge to pediatric dentist. Among restorative treatment options, prefabricated crown and biological and resin composite restoration either by means of direct or indirect technique are mentioned in the literature. This paper presents the clinical sequence of rehabilitation of maxillary anterior primary teeth. Endodontic treatment was followed by the placement of a glass fibre-reinforced composite resin post. The crown reconstruction was done with composite restoration. Resin glass fibre post has best properties in elasticity, translucency, adaptability, tenaciousness, and resistance to traction and to impact. Along with ease of application, fiber can be used as an alternative to traditionally used materials in the management of early childhood caries. PMID:22567447

  17. Evaluation of Vickers hardness of different types of acrylic denture base resins with and without glass fibre reinforcement.

    PubMed

    Farina, Ana Paula; Cecchin, Doglas; Soares, Rodrigo Gonçalves; Botelho, André Luís; Takahashi, Jessica Mie Ferreira Koyama; Mazzetto, Marcelo Oliveira; Mesquita, Marcelo Ferraz

    2012-06-01

    To evaluate the Vickers hardness of different acrylic resins for denture bases with and without the addition of glass fibres. It has been suggested that different polymerisation methods, as well as the addition of glass fibre (FV) might improve the hardness of acrylic. Five types of acrylic resin were tested: Vipi Wave (VW), microwave polymerisation; Vipi Flash (VF), auto-polymerisation; Lucitone (LT), QC20 (QC) and Vipi Cril (VC), conventional heat-polymerisation, all with or without glass fibre reinforcement (GFR) and distributed into 10 groups (n = 12). Specimens were then submitted to Vickers hardness testing with a 25-g load for 30 s. All data were submitted to anova and Tukey's HSD test. A significant statistical difference was observed with regard to the polymerisation method and the GFR (p < 0.05). Without the GFR, the acrylic resin VC presented the highest hardness values, and VF and LT presented the lowest. In the presence of GFR, VC resin still presented the highest Vickers hardness values, and VF and QC presented the lowest. The acrylic resin VC and VW presented higher hardness values than VF and QC resins. Moreover, GFR increased the Vickers hardness of resins VW, VC and LT. © 2010 The Gerodontology Society and John Wiley & Sons A/S.

  18. Effect of monomer composition of polymer matrix on flexural properties of glass fibre-reinforced orthodontic archwire.

    PubMed

    Ohtonen, J; Vallittu, P K; Lassila, L V J

    2013-02-01

    To compare force levels obtained from glass fibre-reinforced composite (FRC) archwires. Specifically, FRC wires were compared with polymer matrices having different dimethacrylate monomer compositions. FRC material (E-glass provided by Stick Tech Ltd, Turku, Finland) with continuous unidirectional glass fibres and four different types of dimethacrylate monomer compositions for the resin matrix were tested. Cross-sectionally round FRC archwires fitting into the 0.3 mm slot of a bracket were divided into 16 groups with six specimens in each group. Glass fibres were impregnated by the manufacturer, and they were initially light-cured by hand light-curing unit or additionally post-cured in light-curing oven. The FRC archwire specimens were tested at 37°C according to a three-point bending test in dry and wet conditions using a span length of 10 mm and a crosshead speed of 1.0 mm/minute. The wires were loaded until final failure. The data were statistically analysed using analysis of variance (ANOVA). The dry FRC archwire specimens revealed higher load values than water stored ones, regardless of the polymer matrix. A majority of the FRC archwires showed higher load values after being post-cured. ANOVA revealed that the polymer matrix, curing method, and water storage had a significant effect (P < 0.05) on the flexural behaviour of the FRC archwire. Polymer matrix composition, curing method, and water storage affected the flexural properties and thus, force level and working range which could be obtained from the FRC archwire.

  19. Reusing fly ash in glass fibre reinforced cement: a new generation of high-quality GRC composites.

    PubMed

    Payá, J; Bonilla, M; Borrachero, M V; Monzó, J; Peris-Mora, E; Lalinde, L F

    2007-01-01

    New composite materials based on an alkali-resistant glass-fibre reinforced cement (AR-GRC) system are being developed by using fly ash (FA) produced at coal thermoelectric power plants, and fluid catalytic cracking catalyst residue (FC3R) from the petrol industry as cement replacement materials. These wastes are reactive from the pozzolanic viewpoint, and modify the nature and the microstructure of the cement matrix when a part of the Portland cement is replaced in the formulation of GRC. Several microstructural and mechanical aspects are being studied for AR-GRC systems. The behaviour of composites exposed to ageing shows that the pozzolanic activity of the ground FA added in high amounts and its mixture with the FC3R increase the flexural strength and no evidences of strength decay are observed. Additionally, the fibres due to the high alkalinity of the cementing matrix can be deteriorated. Fibres in the control (only Portland cement) and FC3R containing composites were attacked, whereas composites with FA and their mixture with FC3R show that the fibres have not been attacked, due to the pozzolanic activity of replacing materials that reduce the calcium hydroxide content in the cementing matrix.

  20. Incorporation of glass-reinforced hydroxyapatite microparticles into poly(lactic acid) electrospun fibre mats for biomedical applications.

    PubMed

    Santos, Daniel; Correia, Cristina O; Silva, Dina M; Gomes, Pedro S; Fernandes, Maria H; Santos, José D; Sencadas, Vitor

    2017-06-01

    Tissue engineering is constantly evolving towards novel materials that mimic the properties of the replaced injured tissue or organ. A hybrid electrospun membrane of electroactive poly(l-acid lactic) (PLLA) polymer with glass reinforced hydroxyapatite (Bonelike®) microparticles placed among the polymer fibres in a morphology like "islands in the sea" was processed. The incorporation of 60 to 80wt% Bonelike® bone grafts granules with ≤150μm into the polymer solution lead to an amorphous polymeric fibre membranes, and a decrease of the average polymer fibre diameter from 550±150nm for neat PLA down to 440±170nm for the hybrid composite. The presence of Bonelike® in the polymer mats reduced the activation energy for thermal degradation from 134kJ·mol(-1), obtained for the neat PLLA membranes down to 71kJ·mol(-1), calculated for the hybrid composite membranes. In vitro cell culture results suggest that the developed processing method does not induce cytotoxic effects in MG 63 osteoblastic cells, and creates an environment that enhances cell proliferation, when compared to the neat PLLA membrane. The simplicity and scalability of the processing method suggests a large application potential of this novel hybrid polymer-microparticles fibre membranes for bone regenerative medicine. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Trends in Occupational Exposure to Styrene in the European Glass Fibre-Reinforced Plastics Industry

    PubMed Central

    Van Rooij, J. G. M.; Kasper, A.; Triebig, G.; Werner, P.; Kromhout, H.

    2008-01-01

    Aim: This study presents temporal trends of styrene exposure for workers in the European glass fibre-reinforced plastics (GRP) industry during the period 1966–2002. Methods: Data of personal styrene exposure measurements were retrieved from reports, databases and peer-reviewed papers. Only sources with descriptive statistics of personal measurements were accepted. The styrene exposure data cover personal air samples and biological monitoring data, that is, urinary styrene metabolites (mandelic acid and/or phenylglyoxylic acid) and styrene in blood. Means of series of measurements were categorized by year, country, production process, job and sampling strategy. Linear mixed models were used to identify temporal trends and factors affecting exposure levels. Results: Personal exposure measurements were available from 60 reports providing data on 24145 1–8-h time-weighted average shift personal air samples. Available data of biological exposure indicators included measurements of mandelic acid in post-shift urine (6361 urine samples being analysed). Trend analyses of the available styrene exposure data showed that the average styrene concentration in the breathing zone of open-mould workers in the European GRP industry has decreased on average by 5.3% per year during the period 1966–1990 and by only 0.4% annually in the period after 1990. The highest exposures were measured in Southern Europe and the lowest exposures in Northern Europe with Central Europe in between. Biological indicators of styrene (mandelic acid in post-shift urine) showed a somewhat steeper decline (8.9%), most likely because urine samples were collected in companies that showed a stronger decrease of styrene exposure in air than GRP companies where no biological measurements were carried out. PMID:18550625

  2. Trends in occupational exposure to styrene in the European glass fibre-reinforced plastics industry.

    PubMed

    Van Rooij, J G M; Kasper, A; Triebig, G; Werner, P; Jongeneelen, F J; Kromhout, H

    2008-07-01

    This study presents temporal trends of styrene exposure for workers in the European glass fibre-reinforced plastics (GRP) industry during the period 1966-2002. Data of personal styrene exposure measurements were retrieved from reports, databases and peer-reviewed papers. Only sources with descriptive statistics of personal measurements were accepted. The styrene exposure data cover personal air samples and biological monitoring data, that is, urinary styrene metabolites (mandelic acid and/or phenylglyoxylic acid) and styrene in blood. Means of series of measurements were categorized by year, country, production process, job and sampling strategy. Linear mixed models were used to identify temporal trends and factors affecting exposure levels. Personal exposure measurements were available from 60 reports providing data on 24145 1-8-h time-weighted average shift personal air samples. Available data of biological exposure indicators included measurements of mandelic acid in post-shift urine (6361 urine samples being analysed). Trend analyses of the available styrene exposure data showed that the average styrene concentration in the breathing zone of open-mould workers in the European GRP industry has decreased on average by 5.3% per year during the period 1966-1990 and by only 0.4% annually in the period after 1990. The highest exposures were measured in Southern Europe and the lowest exposures in Northern Europe with Central Europe in between. Biological indicators of styrene (mandelic acid in post-shift urine) showed a somewhat steeper decline (8.9%), most likely because urine samples were collected in companies that showed a stronger decrease of styrene exposure in air than GRP companies where no biological measurements were carried out.

  3. The effect of a new formaldehyde-free binder on the dissolution rate of glass wool fibre in physiological saline solution

    PubMed Central

    2013-01-01

    The in-vitro dissolution rate of fibres is a good predictor of the in-vivo behavior and potential health effects of inhaled fibres. This study examines the effect of a new formaldehyde-free carbohydrate-polycarboxylic acid binder on the in-vitro dissolution rate of biosoluble glass fibres. Dissolution rate measurements in pH 7.4 physiological saline solution show that the presence of the binder on wool insulation glass fibres has no effect on their dissolution. There is no measurable difference between the dissolution rates of continuous draw fibres before and after binder was applied by dipping. Nor is there a measurable difference between the dissolution rates of a production glass wool sample with binder and that same sample after removal of the binder by low-temperature ashing. Morphological examination shows that swelling of the binder in the solution is at least partially responsible for the development of open channels around the glass-binder interface early in the dissolution. These channels allow fluid to reach the entire glass surface under the binder coating. There is no evidence of any delay in the dissolution rate as a result of the binder coating. PMID:23587247

  4. The effect of a new formaldehyde-free binder on the dissolution rate of glass wool fibre in physiological saline solution.

    PubMed

    Potter, Russell M; Olang, Nassreen

    2013-04-12

    The in-vitro dissolution rate of fibres is a good predictor of the in-vivo behavior and potential health effects of inhaled fibres. This study examines the effect of a new formaldehyde-free carbohydrate-polycarboxylic acid binder on the in-vitro dissolution rate of biosoluble glass fibres. Dissolution rate measurements in pH 7.4 physiological saline solution show that the presence of the binder on wool insulation glass fibres has no effect on their dissolution. There is no measurable difference between the dissolution rates of continuous draw fibres before and after binder was applied by dipping. Nor is there a measurable difference between the dissolution rates of a production glass wool sample with binder and that same sample after removal of the binder by low-temperature ashing. Morphological examination shows that swelling of the binder in the solution is at least partially responsible for the development of open channels around the glass-binder interface early in the dissolution. These channels allow fluid to reach the entire glass surface under the binder coating. There is no evidence of any delay in the dissolution rate as a result of the binder coating.

  5. Effect of phosphate-based glass fibre surface properties on thermally produced poly(lactic acid) matrix composites.

    PubMed

    Mohammadi, Maziar Shah; Ahmed, Ifty; Muja, Naser; Rudd, Christopher D; Bureau, Martin N; Nazhat, Showan N

    2011-12-01

    Incorporation of soluble bioactive glass fibres into biodegradable polymers is an interesting approach for bone repair and regeneration. However, the glass composition and its surface properties significantly affect the nature of the fibre-matrix interface and composite properties. Herein, the effect of Si and Fe on the surface properties of calcium containing phosphate based glasses (PGs) in the system (50P(2)O(5)-40CaO-(10-x)SiO(2)-xFe(2)O(3), where x = 0, 5 and 10 mol.%) were investigated. Contact angle measurements revealed a higher surface energy, and surface polarity as well as increased hydrophilicity for Si doped PG which may account for the presence of surface hydroxyl groups. Two PG formulations, 50P(2)O(5)-40CaO-10Fe(2)O(3) (Fe10) and 50P(2)O(5)-40CaO-5Fe(2)O(3)-5SiO(2) (Fe5Si5), were melt drawn into fibres and randomly incorporated into poly(lactic acid) (PLA) produced by melt processing. The ageing in deionised water (DW), mechanical property changes in phosphate buffered saline (PBS) and cytocompatibility properties of these composites were investigated. In contrast to Fe10 and as a consequence of the higher surface energy and polarity of Fe5Si5, its incorporation into PLA led to increased inorganic/organic interaction indicated by a reduction in the carbonyl group of the matrix. PLA chain scission was confirmed by a greater reduction in its molecular weight in PLA-Fe5Si5 composites. In DW, the dissolution rate of PLA-Fe5Si5 was significantly higher than that of PLA-Fe10. Dissolution of the glass fibres resulted in the formation of channels within the matrix. Initial flexural strength was significantly increased through PGF incorporation. After PBS ageing, the reduction in mechanical properties was greater for PLA-Fe5Si5 compared to PLA-Fe10. MC3T3-E1 preosteoblasts seeded onto PG discs, PLA and PLA-PGF composites were evaluated for up to 7 days indicating that the materials were generally cytocompatible. In addition, cell alignment along the PGF

  6. Transverse crack initiation under combined thermal and mechanical loading of Fibre Metal Laminates and Glass Fibre Reinforced Polymers

    NASA Astrophysics Data System (ADS)

    van de Camp, W.; Dhallé, M. M. J.; Warnet, L.; Wessel, W. A. J.; Vos, G. S.; Akkerman, R.; ter Brake, H. J. M.

    2017-02-01

    The paper describes a temperature-dependent extension of the classical laminate theory (CLT) that may be used to predict the mechanical behaviour of Fibre Metal Laminates (FML) at cryogenic conditions, including crack initiation. FML are considered as a possible alternative class of structural materials for the transport and storage of liquified gasses such as LNG. Combining different constituents in a laminate opens up the possibility to enhance its functionality, e.g. offering lower specific weight and increased damage tolerance. To explore this possibility, a test programme is underway at the University of Twente to study transverse crack initiation in different material combinations under combined thermal and mechanical loading. Specifically, the samples are tested in a three-point bending experiment at temperatures ranging from 77 to 293 K. These tests will serve as a validation of the model presented in this paper which, by incorporating temperature-dependent mechanical properties and differential thermal expansion, will allow to select optimal material combinations and laminate layouts. By combining the temperature-dependent mechanical properties and the differential thermal contraction explicitly, the model allows for a more accurate estimate of the resulting thermal stresses which can then be compared to the strength of the constituent materials.

  7. The Physical Mechanisms Responsible for the Weathering of Epoxy Resins and Glass Fibre Reinforced Expoxy Resins.

    DTIC Science & Technology

    1980-10-01

    Identify by block number) 20. The application and development of a number of optical techniques designed to obtain experimental measurements of the...Whan Dal Entered) 8. field present around an individual fibre to be measured using an oblique incidence photoelastic method. Another, particularising...promise is that in which- the load transferred from resin to fibre is measured photoelastically. A microscope with rectified optics has improved our

  8. An experimental study of non-destructive testing on glass fibre reinforced polymer composites after high velocity impact event

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    A non-destructive testing method on Glass Fibre Reinforced Polymer (GFRP) after high velocity impact event using single stage gas gun (SSGG) is presented. Specimens of C- type and E-type fibreglass reinforcement, which were fabricated with 6mm, 8mm, 10mm and 12mm thicknesses and size 100 mm x 100 mm, were subjected to a high velocity impact with three types of bullets: conical, hemispherical and blunt at various gas gun pressure levels from 6 bar to 60 bar. Visual observation techniques using a lab microscope were used to determine the infringed damage by looking at the crack zone. Dye penetrants were used to inspect the area of damage, and to evaluate internal and external damages on the specimens after impact. The results from visual analysis of the impacted test laminates were discussed and presented. It was found that the impact damage started with induced delamination, fibre cracking and then failure, simultaneously with matrix cracking and breakage, and finally followed by the fibres pulled out. C-type experienced more damaged areas compared to E-type of GFRP.

  9. Influence of 2% chlorhexidine digluconate on bond strength of a glass-fibre post luted with resin or glass-ionomer based cement.

    PubMed

    de Araújo, Diana Ferreira Gadelha; Chaves, Larissa Pinceli; Bim, Odair; Pimentel Garcia, Fernanda Cristina; Ishikiriama, Sérgio Kiyoshi; Honório, Heitor Marques; Wang, Linda

    2014-06-01

    This study evaluated the influence of 2% chlorhexidine digluconate (CHX) on the bond strength (BS) of a glass-fibre post to the root canal, regarding the cements (dual-cured resin or resin-modified glass-ionomer cement), the root thirds and the time of storage. Eighty bovine roots were selected and endodontically treated, before being randomly assigned to the following groups according to the luting protocol: ARC (RelyX ARC); ARC+CHX; RL (RelyX Luting 2); and RL+CHX. After 24 h of luting, the roots were sliced to obtain 1 mm-thick slices. Half of each group was submitted to either 7-day or 6-month storage in artificial saliva (n=10). The specimens were subjected to push-out tests with a crosshead speed of 0.5 mm/min. The data were analysed with four-way ANOVA and Tukey's test (P≤0.05). The failure modes were analysed with a digital microscope (50× and 200×). ARC yielded a significantly higher BS compared to RL (P<0.001). Despite CHX exerted a significant effect; it depends on the interaction with the luting cement and time (P<0.001). Thus, CHX decreased the values of BS to those of ARC after 6 months (P<0.001). On the 7th day of storage, the ARC+CHX presented higher BS to the cervical and middle thirds compared to RL+CHX (P=0.012). Time solely was not a significant factor (P=0.081). Adhesive cement-dentine type and mixed failures were predominant modes for the ARC groups. For the RL groups, the main failures were adhesive cement-post and mixed modes. Glass-fibre posts luted with RelyX ARC dual-cure resin cement exhibited higher BS than those luted with RelyX Luting 2 resin-modified glass-ionomer cement. Furthermore, CHX was not effective to improve the BS and negatively affected the BS of RelyX ARC after 6 months of storage. The use of chlorhexidine solution seems not to improve the bond strength of fibre posts to root canals, disregarding the composition of the luting cement. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. The effect of the application of gaseous ozone and ND:YAG laser on glass-fibre post bond strength.

    PubMed

    Kıvanç, Bağdagül H; Arısu, Hacer D; Ozcan, Suat; Görgül, Güliz; Alaçam, Tayfun

    2012-12-01

    The aim of this study was to investigate the effects of the application of gaseous ozone and Nd:YAG laser on glass-fibre post bond strength. Forty-two madibular premolar roots were cut, endodontically instrumented and irrigated with 2.5% NaOCl. Post spaces were prepared and roots were divided into three groups (n = 14). The antimicrobial pretreatment was conducted as follows: gaseous ozone, Nd:YAG laser and control (no additional disinfection methods). Scanning electron microscope analysis was made for each group (n = 2). A resin cement was used for luting the posts. For push-out test, each root was cut horizontally (two cervical, two middle and two apical). Statistical analyses were performed with one-way anova (α = 0.05). Fracture types were observed. There was no statistically significant difference between the groups (P > 0.05). There were statistically significant differences in cervical and apical segments of laser and control groups (P < 0.05). The disinfection of the post spaces with Nd:YAG laser and ozone had no adverse effects on bond strength of glass-fibre post. © 2010 The Authors. Australian Endodontic Journal © 2010 Australian Society of Endodontology.

  11. Biomimetic self-healing of advanced composite structures using hollow glass fibres

    NASA Astrophysics Data System (ADS)

    Trask, R. S.; Bond, I. P.

    2006-06-01

    The use of functional repair components stored inside hollow reinforcing fibres is being considered as a self-repair system for future composite structures. The incorporation of a self-healing capability within a variety of materials, including fibre reinforced polymers (FRPs), has been investigated by a number of workers previously. This paper considers the placement of self-healing plies within an FRP to mitigate damage occurrence and restore mechanical strength. The flexural strength results indicate that the inclusion of hollow fibres results in an initial strength reduction of 16% from a baseline FRP laminate. However, the effect of impact damage on the performance of the baseline FRP laminate and the laminate containing the hollow fibre layers was comparable, with a flexural strength typically 72-74% of the undamaged state. Self-healing of the damage site saw the laminate recover 87% of the undamaged baseline FRP laminate's strength. This study provides clear evidence that an FRP laminate containing hollow fibre layers can successfully self-heal. This result suggests that biomimetic repair is now possible for advanced composite structures.

  12. Cytocompatibility, mechanical and dissolution properties of high strength boron and iron oxide phosphate glass fibre reinforced bioresorbable composites.

    PubMed

    Sharmin, Nusrat; Hasan, Muhammad S; Parsons, Andrew J; Rudd, Chris D; Ahmed, Ifty

    2016-06-01

    In this study, Polylactic acid (PLA)/phosphate glass fibres (PGF) composites were prepared by compression moulding. Fibres produced from phosphate based glasses P2O5-CaO-MgO-Na2O (P45B0), P2O5-CaO-MgO-Na2O-B2O3 (P45B5), P2O5-CaO-MgO-Na2O-Fe2O3 (P45Fe3) and P2O5-CaO-MgO-Na2O-B2O3-Fe2O3 (P45B5Fe3) were used to reinforce the bioresorbable polymer PLA. Fibre mechanical properties and degradation rate were investigated, along with the mechanical properties, degradation and cytocompatibility of the composites. Retention of the mechanical properties of the composites was evaluated during degradation in PBS at 37°C for four weeks. The fibre volume fraction in the composite varied from 19 to 23%. The flexural strength values (ranging from 131 to 184MPa) and modulus values (ranging from 9.95 to 12.29GPa) obtained for the composites matched those of cortical bone. The highest flexural strength (184MPa) and modulus (12.29GPa) were observed for the P45B5Fe3 composite. After 28 days of immersion in PBS at 37°C, ~35% of the strength profile was maintained for P45B0 and P45B5 composites, while for P45Fe3 and P45B5Fe3 composites ~40% of the initial strength was maintained. However, the overall wet mass change of P45Fe3 and P45B5Fe3 remained significantly lower than that of the P45B0 and P45B5 composites. The pH profile also revealed that the P45B0 and P45B5 composites degraded quicker, correlating well with the degradation profile. From SEM analysis, it could be seen that after 28 days of degradation, the fibres in the fractured surface of P45B5Fe3 composites remain fairly intact as compared to the other formulations. The in vitro cell culture studies using MG63 cell lines revealed both P45Fe3 and P45B5Fe3 composites maintained and showed higher cell viability as compared to the P45B0 and P45B5 composites. This was attributed to the slower degradation rate of the fibres in P45Fe3 and P45B5Fe3 composites as compared with the fibres in P45B0 and P45B5 composites. Copyright © 2015

  13. Fibre Tip Sensors for Localised Temperature Sensing Based on Rare Earth-Doped Glass Coatings

    PubMed Central

    Schartner, Erik P.; Monro, Tanya M.

    2014-01-01

    We report the development of a point temperature sensor, based on monitoring upconversion emission from erbium:ytterbium-doped tellurite coatings on the tips of optical fibres. The dip coating technique allows multiple sensors to be fabricated simultaneously, while confining the temperature-sensitive region to a localised region on the end-face of the fibre. The strong response of the rare earth ions to changing temperature allows a resolution of 0.1–0.3 °C to be recorded over the biologically relevant range of temperatures from 23–39 °C. PMID:25407907

  14. Fibre tip sensors for localised temperature sensing based on rare earth-doped glass coatings.

    PubMed

    Schartner, Erik P; Monro, Tanya M

    2014-11-17

    We report the development of a point temperature sensor, based on monitoring upconversion emission from erbium:ytterbium-doped tellurite coatings on the tips of optical fibres. The dip coating technique allows multiple sensors to be fabricated simultaneously, while confining the temperature-sensitive region to a localised region on the end-face of the fibre. The strong response of the rare earth ions to changing temperature allows a resolution of 0.1-0.3 °C to be recorded over the biologically relevant range of temperatures from 23-39 °C.

  15. The effect of two fibre impregnation methods on the cytotoxicity of a glass and carbon fibre-reinforced acrylic resin denture base material on oral epithelial cells and fibroblasts.

    PubMed

    Sipahi, Cumhur; Ozen, Julide; Ural, A Ugur; Dalkiz, Mehmet; Beydemir, Bedri

    2006-09-01

    Acrylic resin dentures may have cytotoxic effects on oral soft tissues. However, there is sparse data about the cytotoxic effect of fibre-reinforced acrylic resin denture base materials. The purpose of this in vitro study was to determine the effect of two fibre impregnation methods on the cytotoxicity of a glass and carbon fibre-reinforced heat-polymerized acrylic resin denture base material on oral epithelial cells and fibroblasts. One hundred acrylic resin discs were assigned to five experimental groups (n = 20). One of the groups did not include any fibre. Two groups consisted of silane and monomer treated glass fibres (Vetrolex) impregnated into acrylic resin (QC-20) discs. The other two groups consisted of silane and monomer treated carbon fibres (Type Tenox J, HTA). Untreated cell culture was used as positive control. The human oral epithelial cell line and buccal fibroblast cultures were exposed to test specimens. The cytotoxicity of the test materials was determined by succinic dehydrogenase activity (MTT method) after 24 and 72 h exposures. Data were analysed with a statistical software program (SPSSFW, 9.0). A one-way analysis of variance (anova) test and Bonferroni test were used for the comparisons between the groups. All statistical tests were performed at the 0.95 confidence level (P < 0.05). After 24 and 72 h incubation, cell viability percentages of all experimental groups showed significant decrease according to the positive control cell culture. Fibroblastic cell viability percentages of silane and monomer treated fibre-reinforced groups were lower than the unreinforced group. Cell viability of monomer-treated groups displayed the lowest percentages. Elapsed incubation time decreased epithelial cell viability in silane-treated groups. Fibroblastic cell viability was not influenced by elapsed time except the unreinforced group.

  16. An exploration of the relationship of chemical and physical parameters in the micromechanical characterisation of the apparent interfacial strength in glass fibre epoxy systems

    NASA Astrophysics Data System (ADS)

    Thomason, J. L.; Yang, L.; Bryce, D.; Minty, R.

    2016-07-01

    This paper focuses on the cure shrinkage and the thermomechanical properties of an amine cured epoxy resin system and its adhesion to glass fibre. The fibre-matrix interfacial shear strength (IFSS) was characterized using the microbond test over a range of test temperatures and a range of amine:epoxy ratios. The apparent IFSS in this glass-epoxy system was shown to be strongly dependent on the testing temperature and the matrix stoichiometry. High levels of cure shrinkage were measured in the IFSS microdroplets which resulted in internal stresses causing significant levels of droplet deformation. The results presented here can be interpreted as providing further support for the hypothesis that a significant fraction of the interfacial stress transfer capability in epoxy composites can be attributed to a combination of residual radial compressive stress and static friction at the fibre-matrix interface.

  17. Multidisciplinary approach to the rehabilitation of a crown fracture with glass-fibre-reinforced composite: a case report.

    PubMed

    Altun, Ceyhan; Tözüm, Tolga Fikret; Güven, Günseli

    2008-05-01

    Traumatic tooth injuries are common in children. When permanent teeth are involved, it can be a challenge to save these teeth. This clinical case study describes the multidisciplinary treatment of a complex crown fracture and luxation of a right maxillary incisor along with esthetic management. After periodontal surgery including guided bone regeneration and endodontic treatment, we used a glass-fibre-reinforced composite post to increase retention and distribute stress along the root. The restoration was completed using composite in an incremental technique. During follow-up appointments, clinical and radiographic examinations revealed no root canal or periodontal problems, suggesting the efficacy of the treatment in retaining the fractured tooth. Periodontal surgery with endodontic treatment is an alternative treatment for severe trauma in permanent teeth.

  18. Effect of post-space treatments on the push-out bond strength and failure modes of glass fibre posts.

    PubMed

    Arisu, Hacer Deniz; Kivanç, Bağdagül Helvacioğlu; Sağlam, Baran C; Şimşek, Eser; Görgül, Güliz

    2013-04-01

    The aim of this study was to evaluate the effect of different post-space treatments on the push-out bond strength and failure modes of glass fibre posts. Forty mandibular premolar roots were cut and endodontically treated. Post spaces were prepared and roots were divided into four groups. In group 1 distilled water irrigation (control), in group 2 2.25% NaOCl irrigation, in group 3 2.25% NaOCl + 17% EDTA irrigation were done and in group 4 diode laser was applied to the prepared post spaces. Scanning electron microscope (SEM) analysis was made for each group. Fibre posts were then luted with resin cement. Each root was prepared for push-out test. Data were statistically analysed with anova (P = 0.05). After push-out test, the failure modes were observed but not statistically analysed. There were statistically significant differences between Group 3 and Group 2 in both regions (P < 0.05), also in the middle region of Group 4 and Group 2 (P < 0.05). Cervical root segments showed higher bond strengths than middle ones in all groups (P < 0.05). The highest bond strength values were obtained from NaOCl/EDTA and the lowest bond strength values were obtained from NaOCl for both regions. © 2010 The Authors. Australian Endodontic Journal © 2010 Australian Society of Endodontology.

  19. Effect of ferrule height and glass fibre post length on fracture resistance and failure mode of endodontically treated teeth.

    PubMed

    Abdulrazzak, Shurooq S; Sulaiman, Eshamsul; Atiya, Basim K; Jamaludin, Marhazlinda

    2014-08-01

    The purpose of this study was to evaluate the combined effect of ferrule height and post length on fracture resistance and failure mode of endodontically treated teeth restored with glass fibre posts, composite resin cores and crowns. Ninety human maxillary central incisors were endodontically treated and divided into three groups (n = 30) according to the ferrule heights: 4, 2 and 0 mm, respectively. Post spaces in each group were prepared at 2/3, 1/2 and 1/3 of the root length (n = 10). The specimens were received fibre posts, composite resin core build up and cast metal crowns. After thermocycling, compressive static load was applied at an angle of 135° to the crowns. Two-way analysis of variance showed significant differences in the failure load in the ferrule height groups, no significant differences in post length groups and no significant interaction between ferrule heights and post lengths. More restorable failure modes were observed. © 2013 Australian Society of Endodontology.

  20. Interface shear strength and fracture behaviour of porous glass-fibre-reinforced composite implant and bone model material.

    PubMed

    Nganga, Sara; Ylä-Soininmäki, Anne; Lassila, Lippo V J; Vallittu, Pekka K

    2011-11-01

    Glass-fibre-reinforced composites (FRCs) are under current investigation to serve as durable bone substitute materials in load-bearing orthopaedic implants and bone implants in the head and neck area. The present form of biocompatible FRCs consist of non-woven E-glass-fibre tissues impregnated with varying amounts of a non-resorbable photopolymerisable bifunctional polymer resin with equal portions of both bis-phenyl-A-glycidyl dimethacrylate (BisGMA) and triethyleneglycol dimethacrylate (TEGDMA). FRCs with a total porosity of 10-70 vol% were prepared, more than 90 vol% of which being functional (open pores), and the rest closed. The pore sizes were greater than 100 μm. In the present study, the push-out test was chosen to analyse the shear strength of the interface between mechanically interlocked gypsum and a porous FRC implant structure. Gypsum was used as a substitute material for natural bone. The simulative in vitro experiments revealed a significant rise of push-out forces to the twofold level of 1147 ± 271 N for an increase in total FRC porosity of 43%. Pins, intended to model the initial mechanical implant fixation, did not affect the measured shear strength of the gypsum-FRC interface, but led to slightly more cohesive fracture modes. Fractures always occurred inside the gypsum, it having lower compressive strength than the porous FRC structures. Therefore, the largest loads were restricted by the brittleness of the gypsum. Increases of the FRC implant porosity tended to lead to more cohesive fracture modes and higher interfacial fracture toughness. Statistical differences were confirmed using the Kruskal-Wallis test. The differences between the modelled configuration showing gypsum penetration into all open pores and the real clinical situation with gradual bone ingrowth has to be considered. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Effect of 2% chlorhexidine digluconate on bond strength of a glass-fibre post to root dentine.

    PubMed

    Wang, L; Pinto, T A; Silva, L M; Araújo, D F G; Martins, L M; Hannas, A R; Pedreira, A P R V; Francisconi, P A S; Honório, H M

    2013-09-01

    To assess the immediate influence of dentine bonding systems (DBS) associated with 2% chlorhexidine digluconate (CHX) on glass-fibre post-bond strength to root dentine, in terms of coronal, middle and apical thirds. Sixty bovine roots were root filled and randomly assigned to 1 of 6 groups (n = 10): SBMP (3-step etch-and-rinse system, Scotchbond Multi-Purpose), SB (2-step etch-and-rinse system, Single Bond 2), SE (2-step self-etching system, Clearfil SE Bond) and SBMP-CHX, SB-CHX and SE-CHX, respectively, associated with CHX. For all groups, a glass-fibre post was luted with a dual-cure resin cement, RelyX ARC. After 7-day storage, specimens were subjected to the push-out test. Failure modes were analysed under optical microscopy (40x). Bond strength values were statistically analysed by two-way anova and Bonferroni tests (P < 0.05). The effect of DBS was significant (P < 0.05), and SE reached higher bond strength in comparison with the other DBS tested. CHX association did not show improvement with any DBS (P > 0.05); rather, it negatively affected SE, which was detected for all thirds. There was no difference between thirds (P > 0.05), except for the SE-CHX, which presented lower values for the apical third (P < 0.05). Adhesive cement/dentine adhesive failure was predominant for all groups. CHX did not influence the failure mode for any DBS (P > 0.05). The performance of the dentine bonding systems was material dependent. CHX did not improve immediate bond strength; however, CHX negatively affected the bond strength of the self-etching system, especially in the third apical. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  2. Mining landfills for recyclables

    SciTech Connect

    Spencer, R.

    1991-02-01

    The New York State Energy Research and Development Authority (NYSERDA) and the Department of Environmental Conservation (DEC) began a landfill reclamation experiment in Edinburgh, NY, a rural community in the Adirondack Park. According to NYSERDA's Fact Sheet about the project, landfill reclamation is a process of excavating a landfill using conventional surface mining technology to recover metals, glass, plastics and combustibles, soils, and the land resource itself. The recovered site can then be either upgraded into a state-of-the-art landfill, if appropriate, closed or redeveloped for some other suitable purpose. As an energy-related public benefit corporation, NYSERDA is particularly interested in the potential energy value of combustible material reclaimed from landfills. With an energy content of over 11 million BTUs per ton, this translates to the energy equivalent of 275 million barrels of oil.

  3. Rare-Earth Oxide Ion (Tm3+, Ho3+, and U3+) Doped Glasses and Fibres for 1.8 to 4 Micrometer Coherent and Broadband Sources

    DTIC Science & Technology

    2006-07-24

    other optical devices. The transmission range of tellurium based glasses extends into the mid infra red up to around 5 µm and has a low cut-off phonon...the high rare earth ion solubility, makes tellurium based glass a good host within which to examine the longer wavelength transitions of Tm3+ and Ho3...Earth Oxide Ion (Tm3+, Ho3+, And U3+) Doped Glasses And Fibres For 1.8 To 4 Micrometer Coherent And Broadband Sources 5c. PROGRAM ELEMENT NUMBER 5d

  4. Effect of Endodontic Irrigating Solutions on the Micro Push-out Bond Strength of a Fibre Glass Dowel

    PubMed Central

    Crispim da Silveira, Olimpia; Bras da Silva, Rodivan; Dametto, Fabio Roberto; Machado, Claudia Tavares; Souza dos Santos, Alex Jose

    2014-01-01

    Purpose To evaluate the effect of different endodontic irrigating solutions on the micro push-out bond strength of a fiber glass dowel. Material and Methods Seventy 16-mm long root segments of bovine incisors were prepared and randomly assigned to 7 groups (n=10) according to the type of irrigating solution used prior to the cementation of the intra-radicular fiber glass dowels: G1: 5.25% NaOCl + 17% EDTA; G2: 5.25% NaOCl; G3: 17% EDTA; G4: 2% chlorhexidine gel; G5: 70% alcohol; G6: 11.5% polyacrylic acid; and G7: saline (control). After treatment of intracanal dentin, the glass fibre dowels were cemented with self-adhesive resin cement (RelyX Unicem). Six slices with the thickness of 1.00 ± 0.05 mm were obtained from each tooth at the coronal, middle and apical root thirds (2 slices per third) using a low-speed saw. Micro push-out tests were performed at a crosshead speed of 0.5mm/min and the data (MPa) were analyzed statistically by ANOVA and Tukey’s and Dunnett’s tests. Results There were statistically significant differences (p<0.0001) among the irrigating solutions, but no significant difference (p=0.0591) was found among the root thirds. G5 presented the highest bond strength mean of all groups (p<0.0001). The use of 70% alcohol increased the adhesion values by 53% compared to the group control. Conclusion The use of 70% alcohol increased the bond strength of the fiber glass dowel to the dentin walls. However, the push-out bond strength between the dowel and the root dentin was not affected by the root third (coronal, middle and apical). PMID:27688347

  5. Effect of Endodontic Irrigating Solutions on the Micro Push-out Bond Strength of a Fibre Glass Dowel.

    PubMed

    Crispim da Silveira, Olimpia; Bras da Silva, Rodivan; Dametto, Fabio Roberto; Machado, Claudia Tavares; Souza Dos Santos, Alex Jose; Cavalcanti, Alessandro Leite

    2014-03-01

    To evaluate the effect of different endodontic irrigating solutions on the micro push-out bond strength of a fiber glass dowel. Seventy 16-mm long root segments of bovine incisors were prepared and randomly assigned to 7 groups (n=10) according to the type of irrigating solution used prior to the cementation of the intra-radicular fiber glass dowels: G1: 5.25% NaOCl + 17% EDTA; G2: 5.25% NaOCl; G3: 17% EDTA; G4: 2% chlorhexidine gel; G5: 70% alcohol; G6: 11.5% polyacrylic acid; and G7: saline (control). After treatment of intracanal dentin, the glass fibre dowels were cemented with self-adhesive resin cement (RelyX Unicem). Six slices with the thickness of 1.00 ± 0.05 mm were obtained from each tooth at the coronal, middle and apical root thirds (2 slices per third) using a low-speed saw. Micro push-out tests were performed at a crosshead speed of 0.5mm/min and the data (MPa) were analyzed statistically by ANOVA and Tukey's and Dunnett's tests. There were statistically significant differences (p<0.0001) among the irrigating solutions, but no significant difference (p=0.0591) was found among the root thirds. G5 presented the highest bond strength mean of all groups (p<0.0001). The use of 70% alcohol increased the adhesion values by 53% compared to the group control. The use of 70% alcohol increased the bond strength of the fiber glass dowel to the dentin walls. However, the push-out bond strength between the dowel and the root dentin was not affected by the root third (coronal, middle and apical).

  6. Specimen Design for Sustained Load Testing of Parallel-Laid Glass Fibre Reinforced Plastics.

    DTIC Science & Technology

    prepared by molding on a sheet of woven glass fabric and stripping this off just before bonding, to leave a roughened surface. The test specimens are 1/2 inch wide strips cut from the laminates. (Author, modified-PL)

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

    NASA Technical Reports Server (NTRS)

    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.

  8. Setting kinetics and mechanical properties of flax fibre reinforced glass ionomer restorative materials

    PubMed Central

    Abou Neel, Ensanya Ali; Young, Anne M.

    2017-01-01

    Regardless of the excellent properties of glass ionomer cements, their poor mechanical properties limit their applications to non-load bearing areas. This study aimed to investigate the effect of incorporated short, chopped and randomly distributed flax fibers (0, 0.5, 1, 2.5, 5 and 25 wt%) on setting reaction kinetics, and mechanical and morphological properties of glass ionomer cements. Addition of flax fibers did not significantly affect the setting reaction extent. According to their content, flax fibers increased the compressive (from 148 to 250 MPa) and flexure strength (from 20 to 42 MPa). They also changed the brittle behavior of glass ionomer cements to a plastic one. They significantly reduced the compressive (from 3 to 1.3 GPa) and flexure modulus (from 19 to 14 GPa). Accordingly, flax fiber-modified glass ionomer cements could be potentially used in high-stress bearing areas. PMID:28808218

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

    NASA Technical Reports Server (NTRS)

    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.

  10. Setting kinetics and mechanical properties of flax fibre reinforced glass ionomer restorative materials.

    PubMed

    Ali Abou Neel, Ensanya; M Young, Anne

    2017-01-19

    Regardless of the excellent properties of glass ionomer cements, their poor mechanical properties limit their applications to non-load bearing areas. This study aimed to investigate the effect of incorporated short, chopped and randomly distributed flax fibers (0, 0.5, 1, 2.5, 5 and 25 wt%) on setting reaction kinetics, and mechanical and morphological properties of glass ionomer cements. Addition of flax fibers did not significantly affect the setting reaction extent. According to their content, flax fibers increased the compressive (from 148 to 250 MPa) and flexure strength (from 20 to 42 MPa). They also changed the brittle behavior of glass ionomer cements to a plastic one. They significantly reduced the compressive (from 3 to 1.3 GPa) and flexure modulus (from 19 to 14 GPa). Accordingly, flax fiber-modified glass ionomer cements could be potentially used in high-stress bearing areas.

  11. GLASS FIBER REINFORCED PLASTICS,

    DTIC Science & Technology

    Contents: Fibrous glass fillers Binders used in the glass plastic industry Method of manufacturing glass plastics and glass plastic articles Properties of fiberglass Primary areas for use of glass fibre reinforced plastics

  12. CW bismuth fibre laser

    SciTech Connect

    Dianov, Evgenii M; Dvoyrin, V V; Mashinsky, V M; Umnikov, A A; Yashkov, M V; Gur'yanov, A N

    2005-12-31

    A new fibre laser based on a bismuth-doped aluminosilicate glass fibre is proposed and fabricated. CW lasing is obtained in the spectral region between 1150 and 1300 nm. The fibres are fabricated by the method of modified chemical vapour deposition. (letters)

  13. Microleakage along glass-fibre posts cemented with three different materials after cyclic loading: a pilot study.

    PubMed

    Barbić, Marija Rogić; Segović, Sanja; Baraba, Anja; Ribarić, Sonja Pezelj; Katunarić, Marina; Anić, Ivica

    2013-06-01

    The purpose of this in vitro study was to evaluate microleakage along glass-fibre posts cemented with three different cements after cyclic loading. After post-space preparation, fifty obturated root canals were randomly divided into three experimental groups and two control groups. In group 1, Glassix posts were cemented using Harvard cement, in group 2, Fuji PLUS cement was used and in group 3, Variolink II was used for post cementation. The specimens were artificially aged by loading in a special testing machine. Coronal leakage was evaluated using a fluid transport system. Posts cemented with Variolink II, showed significantly higher failure rate after loading, compared to group 1 and 2 (p = 0.009). Comparing microleakage in samples that have not failed, specimens cemented with Variolink II showed significantly less fluid transport than specimens cemented with zinc phosphate and glass ionomer cements (p = 0.04 and p = 0.006, respectively). Variolink II cement exibited significantly less fluid movement compared with Harvard and Fuji PLUS cement.

  14. Modeling of the stress-strain behaviour during monotonic and cyclic tensile testing of unidirectional SiC-fibre reinforced BMAS glass-ceramic composites

    SciTech Connect

    Vanswijgenhoven, E.; Wevers, M.; Van Der Biest, O.

    1995-12-01

    A model is proposed which gives a complete description of the stress-strain behaviour during monotonic and cyclic tensile testing of unidirectional SiC-fibre toughened BMAS glass-ceramic matrix composites using parameters describing the microstructure, the micromechanical behaviour, the damage development in matrix and fibre and the residual stress state as input. The model reproduces the main features of the stress-strain behaviour of the material and is versatile enough to take different damage development sequences and residual stress states into account. Furthermore, it offers the possibility to evaluate the impact of changes in microstructure and micromechanical behaviour on the macromechanical behaviour.

  15. A compliant, high failure strain, fibre-reinforced glass-matrix composite

    NASA Technical Reports Server (NTRS)

    Prewo, K. M.

    1982-01-01

    A glass-matrix composite reinforced by discontinuous graphite fibers was produced by hot pressing glass-powder-impregnated two-dimensional arrays of in-plane randomly oriented graphite fibers held together by approximately 5-10% by weight of organic binder (generally polyester). The composite tensile behavior is characterized by a highly nonlinear stress-strain curve which differs markedly from that of either unreinforced glass or a similarly reinforced epoxy-matrix composite. By virtue of this nonlinearity, the composite is able to redistribute applied stresses to achieve a high load-carrying capacity. The fibrous microstructure and the low fiber-matrix bond provide a mechanism for achieving high fracture toughness and unusually high compliance. For a 96%-silica-matrix composite, the strength is retained to over 1000 C.

  16. A compliant, high failure strain, fibre-reinforced glass-matrix composite

    NASA Technical Reports Server (NTRS)

    Prewo, K. M.

    1982-01-01

    A glass-matrix composite reinforced by discontinuous graphite fibers was produced by hot pressing glass-powder-impregnated two-dimensional arrays of in-plane randomly oriented graphite fibers held together by approximately 5-10% by weight of organic binder (generally polyester). The composite tensile behavior is characterized by a highly nonlinear stress-strain curve which differs markedly from that of either unreinforced glass or a similarly reinforced epoxy-matrix composite. By virtue of this nonlinearity, the composite is able to redistribute applied stresses to achieve a high load-carrying capacity. The fibrous microstructure and the low fiber-matrix bond provide a mechanism for achieving high fracture toughness and unusually high compliance. For a 96%-silica-matrix composite, the strength is retained to over 1000 C.

  17. A novel method for preparing the antibacterial glass fibre mat using laser treatment

    NASA Astrophysics Data System (ADS)

    Wiener, Jakub; Shahidi, Sheila; Mkhululi Goba, Makabongwe; Šašková, Jana

    2014-02-01

    In this study, CO2 laser treatment was used as a novel method for creating antibacterial properties on glass mat. Different metallic salts such as CuO, ZnO and AgNO3 were even applied on surface of glass fiber mat, then irradiated with the laser light beam (100 μs). Metal particles were deposited on the surface of samples, and the antibacterial has been developed, through incorporation of metal particles on glass mats. The antibacterial properties of the fabrics were connected with the presence of metal particles on their surface. The amounts of metal particles on the surface were compared using X-ray fluorescence (XRF) and energy dispersive X-ray spectrometer (EDS). Also the morphological properties of the fabrics were observed using a scanning electron microscope (SEM). The experimental work suggests that the change in properties induced by laser can effect an improvement in certain textile products.

  18. Hollow core optical fibres made by glass billet extrusion as sensors for Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Tsiminis, G.; Schartner, E. P.; Hutchinson, M. R.; Ebendorff-Heidepriem, H.

    2016-12-01

    Optical fiber sensors for Raman spectroscopy based on hollow core optical fibers have shown great promise due to their low glass background, and high signal collection efficiency. We have previously demonstrated how glass billet extrusion can be used to make simplified hollow core fibers based on a single suspended ring. In this work we investigate the performance of these optical fibers as sensors for Raman spectroscopy. These fibers are used to excite samples at a range of laser excitation wavelengths to scan across the transmission profile of the optical fibers, allowing comparison of the performance of these fibers against commercially-available alternatives.

  19. Failures Analysis of E-Glass Fibre reinforced pipes in Oil and Gas Industry: A Review

    NASA Astrophysics Data System (ADS)

    Bobba, Sujith; Leman, Z.; Zainuddin, E. S.; Sapuan, S. M.

    2017-07-01

    A comprehensive review is conducted on the failures in the field of manufacturing and installation of E-glass fiber reinforced pipes (GFRP). Some of the failures which are mainly encountered after the installation of E-Glass fiber reinforced pipes are the for nation of air bubbles in between the polyester resin layer and the surface film, dispersion of moisture in between the tubing outer and inner layers after installation, heat released in between the layers of E-glass fiber reinforced pipes due to exothermic reaction which in turn results in the formation of cracks on the surface of the pipe. The recent findings and challenges performed in conducting research regarding the deterioration caused in glass fiber reinforced pipes are highlighted and each type of failure that was identified was illustrated with an appropriate high resolution photograph. Performing creep resistance and fatigue analysis are new aspects which are still requited to be analyzed which ave not been stated in the literature which are nominated.

  20. Investigation of mechanical properties of aluminium reinforced glass fibre polymer composites

    NASA Astrophysics Data System (ADS)

    Kumar, G. B. Veeresh; Pramod, R.

    2017-07-01

    This paper presents the recent work about reinforcing E-glass into Aluminium foil to attain high strength to weight ratio. Aluminium is corrosion resistant, light in weight and ductile, also when alloyed through other metals deliver the greater strengths as desirable for high-tech applications. The density of pure Aluminium is 2.7 g cm3. Electrical grade glass formally known as E-glass, is by far the most used fiber in reinforced plastic composites. It is a high strength material with light weight compared to steel and corrosive resistant. The matrix and reinforcement is bonded with a resin, named Araldite Ly556, which has density at 25 °C, 1.15-1.20 g cm3. Thus gives a good binding structure. In the present work, Aluminium, E-Glass and Epoxy are combined to fabricate a laminate by Hand-Lay process. Hand-lay is the oldest and simplest method used for producing reinforced plastic laminates. The fabricated metal matrix composites are tested for their mechanical properties. The metal laminate is found to render high strength, hardness, flexural strength and increased wear resistance. Further theoretical simulations was carried out to validate the experimental results.

  1. Leaky Landfills.

    ERIC Educational Resources Information Center

    Jones, Linda L. Cronin

    1992-01-01

    Provides background information on landfills and describes an activity where students learn how a modern landfill is constructed and develop an understanding of the reasons for several regulations regarding modern landfill construction. Students design and construct working models of three types of landfills. (PR)

  2. Leaky Landfills.

    ERIC Educational Resources Information Center

    Jones, Linda L. Cronin

    1992-01-01

    Provides background information on landfills and describes an activity where students learn how a modern landfill is constructed and develop an understanding of the reasons for several regulations regarding modern landfill construction. Students design and construct working models of three types of landfills. (PR)

  3. Influence of glass fibre post length and remaining dentine thickness on the fracture resistance of root filled teeth.

    PubMed

    Junqueira, R B; de Carvalho, R F; Marinho, C C; Valera, M C; Carvalho, C A T

    2017-06-01

    To evaluate, ex vivo, the influence of glass fibre post length and remaining thickness of dentine on the fracture resistance of bovine roots, after thermomechanical ageing. Ninety bovine roots of the same size were root filled and randomly distributed into nine groups (n = 10), according to the root weakening protocol (NW - nonweakened; MW - medium weakened; HW - highly weakened) and post length (7 mm; 9 mm and 12 mm). The weakening of roots was performed using diamond burs, resulting in different thicknesses of remaining dentine. The post spaces were prepared, and in the weakened roots, the glass fibre posts were customized with composite resin, to create posts matching the canal size. Chemically activated resin cement was used to lute the posts. After luting, full crowns made of composite resin were attached to a silicon matrix. To reproduce physiological mobility, the roots were covered with polyether and embedded in polyurethane. The thermomechanical cycling was performed (1 200 000 cycles; 88N; 3,8 Hz; 5 ± 1 °C to 55 ± 1 °C). Then, the specimens were subjected to compressive force in a universal testing machine (1 mm min(-1) ; 100 kgf) to analyse the fracture resistance. The specimens were analysed through a stereomicroscope to classify the failure mode (repairable/catastrophic). The values were subjected to statistical analysis (two-way anova and Tukey's test at 5%). The frequencies of failure mode were compared using chi-square test. The association between length and dentine thickness was significant (P > 0.05). The difference was between NW and HW roots for posts of 12 mm in length. There was an association between failure mode and the length and remaining dentine thickness. Reduced dentine thickness in roots with longer posts had lower fracture resistance values, as catastrophic failure was more predominant. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  4. Influence of cyclic freeze-thaw on the parameters of the electric response to the pulse mechanical excitation of concrete reinforced by glass fibre reinforced polymer bars

    NASA Astrophysics Data System (ADS)

    Fursa, T. V.; Petrov, M. V.; Korzenok, I. N.

    2016-02-01

    Studies of the influence of cyclic freeze-thaw on the parameters of electric response from samples of concrete reinforced by glass fibre reinforced polymer (GFRP) bars were conducted. It is found that an increase in the number of freeze-thaw cycles increases the attenuation coefficient of energy of electric responses and moves the centre of gravity of spectrum to the low-frequency area. The results can be used to develop a method of nondestructive testing of reinforced concrete.

  5. Combined technique with glass-fibre-reinforced composite post and original fragment in restoration of traumatized anterior teeth--a case report.

    PubMed

    Altun, Ceyhan; Guven, Gunseli

    2008-12-01

    Dentoalveolar trauma is frequently encountered by dental practitioners. In some instances, saving a child's traumatized permanent teeth can create difficulties for the child, the parents and the dentist. Reattachment of a crown fragment is a conservative treatment that should be considered for crown fractures of anterior teeth. This case describes the clinical reattachment of an original tooth fragment. A 10-year-old male presented at the Department of Pediatric Dentistry with a complex crown fracture of the left maxillary central incisor 1 day after the trauma occurred. Following endodontic treatment, a glass-fibre-reinforced composite root canal post (FRC Postec; Ivoclar Vivadent AG, Schaan, Liechtenstein) was inserted to increase retention and distribute stress along the root. The dental restoration was completed using the original fragment and a dual-cured resin composite (Variolink II; Ivoclar Vivadent AG). Clinical and radiographic examinations at 1-year recall showed the glass-fibre-reinforced composite root canal post and restoration to be in place, indicating the success of the treatment in maintaining the fractured tooth. Thus, we conclude that reattachment of a tooth fragment using a dual-cured resin composite and a glass-fibre-reinforced composite root canal post is an alternative method for the rehabilitation of fractured teeth that offers satisfactory aesthetic and functional outcomes.

  6. Bone attachment to glass-fibre-reinforced composite implant with porous surface.

    PubMed

    Mattila, R H; Laurila, P; Rekola, J; Gunn, J; Lassila, L V J; Mäntylä, T; Aho, A J; Vallittu, P K

    2009-06-01

    A method has recently been developed for producing fibre-reinforced composites (FRC) with porous surfaces, intended for use as load-bearing orthopaedic implants. This study focuses on evaluation of the bone-bonding behaviour of FRC implants. Three types of cylindrical implants, i.e. FRC implants with a porous surface, solid polymethyl methacrylate (PMMA) implants and titanium (Ti) implants, were inserted in a transverse direction into the intercondular trabeculous bone area of distal femurs and proximal tibias of New Zealand White rabbits. Animals were sacrificed at 3, 6 and 12 weeks post operation, and push-out tests (n=5-6 per implant type per time point) were then carried out. At 12 weeks the shear force at the porous FRC-bone interface was significantly higher (283.3+/-55.3N) than the shear force at interfaces of solid PMMA/bone (14.4+/-11.0 N; p<0.001) and Ti/bone (130.6+/-22.2N; p=0.001). Histological observation revealed new bone growth into the porous surface structure of FRC implants. Solid PMMA and Ti implants were encapsulated mostly with fibrous connective tissue. Finite element analysis (FEA) revealed that porous FRC implants had mechanical properties which could be tailored to smooth the shear stress distribution at the bone-implant interface and reduce the stress-shielding effect.

  7. [PVD-layering for increased retention of glass fibre reinforced endodontic posts].

    PubMed

    Edelhoff, Daniel; Weber, Michael; Spiekermann, Hubertus; Marx, Rudolf

    2006-01-01

    For esthetical and biomechanical reasons root canal posts made of fibre-reinforced composite (FRC) have gained an important role in clinical application. Additionally, in contrast to metal or ceramic posts, FRC-posts offer the option of removal. Prior to adhesive placement of FRC-posts the root canal dentin of the non vital tooth and the post surface have to be preconditioned. Up to now the post preconditioning has to be proceeded in the chair side technique. This leads to an additional time expense in the clinical treatment schedule. Also a certain risk of errors in application during chair side conditioning procedure is of concern. Modern PVD-technologies can help to make the treatment by the manufacturer well in advance of the clinical use more efficient and reliable, as well as saving clinicians valuable chair-time. For this reason the apical surfaces of the posts were intensively cleaned and activated, PVD-layered and coated by a conserving transparent layer. This coating has the meaning to protect the surface against environmental contamination and allows the try-in of the posts without any risk of damage of the preconditioned surface. To prove the stability of the layer system under simulated clinical conditions pull out tests after 180 days'storage in physiological saline solution have been performed.

  8. An Optical System to Monitor the Displacement Field of Glass-fibre Posts Subjected to Thermal Loading

    PubMed Central

    Corsalini, Massimo; Pettini, Francesco; Di Venere, Daniela; Ballini, Andrea; Chiatante, Giuseppe; Lamberti, Luciano; Pappalettere, Carmine; Fiorentino, Michele; Uva, Antonio E.; Monno, Giuseppe; Boccaccio, Antonio

    2016-01-01

    Endocanalar posts are necessary to build up and retain coronal restorations but they do not reinforce dental roots. It was observed that the dislodgement of post-retained restorations commonly occurs after several years of function and long-term retention may be influenced by various factors such as temperature changes. Temperature changes, in fact, produce micrometric deformations of post and surrounding tissues/materials that may generate high stress concentrations at the interface thus leading to failure. In this study we present an optical system based on the projection moiré technique that has been utilized to monitor the displacement field of endocanalar glass-fibre posts subjected to temperature changes. Measurements were performed on forty samples and the average displacement values registered at the apical and middle region were determined for six different temperature levels. A total of 480 displacement measurements was hence performed. The values of the standard deviation computed for each of the tested temperatures over the forty samples appear reasonably small which proves the robustness and the reliability of the proposed optical technique. The possible implications for the use of the system in the applicative context were discussed. PMID:27990186

  9. An Optical System to Monitor the Displacement Field of Glass-fibre Posts Subjected to Thermal Loading.

    PubMed

    Corsalini, Massimo; Pettini, Francesco; Di Venere, Daniela; Ballini, Andrea; Chiatante, Giuseppe; Lamberti, Luciano; Pappalettere, Carmine; Fiorentino, Michele; Uva, Antonio E; Monno, Giuseppe; Boccaccio, Antonio

    2016-01-01

    Endocanalar posts are necessary to build up and retain coronal restorations but they do not reinforce dental roots. It was observed that the dislodgement of post-retained restorations commonly occurs after several years of function and long-term retention may be influenced by various factors such as temperature changes. Temperature changes, in fact, produce micrometric deformations of post and surrounding tissues/materials that may generate high stress concentrations at the interface thus leading to failure. In this study we present an optical system based on the projection moiré technique that has been utilized to monitor the displacement field of endocanalar glass-fibre posts subjected to temperature changes. Measurements were performed on forty samples and the average displacement values registered at the apical and middle region were determined for six different temperature levels. A total of 480 displacement measurements was hence performed. The values of the standard deviation computed for each of the tested temperatures over the forty samples appear reasonably small which proves the robustness and the reliability of the proposed optical technique. The possible implications for the use of the system in the applicative context were discussed.

  10. Microleakage along Glassix glass fibre posts cemented with three different materials assessed using a fluid transport system.

    PubMed

    Rogić-Barbić, M; Segović, S; Pezelj-Ribarić, S; Borcić, J; Jukić, S; Anić, I

    2006-05-01

    To evaluate the microleakage along Glassix fibre posts cemented with three different materials. The root canals of maxillary central incisor teeth were filled and restored with Glassix posts (Harald Nordin sa, Chailly/Montreux, Switzerland) cemented with either a zinc-phosphate Harvard cement (Richter & Hoffmann, Harvard Dental GmbH, Berlin, Germany), Fuji PLUS cement (GC Corporation, Tokyo, Japan) or Variolink II cement (Vivadent, Schaan, Lichtenstein) in three groups of 15 canals each. Twenty unrestored canals served as a control group, 10 filled with gutta-percha and sealer (negative control group), the remaining 10 with gutta-percha only (positive control group). Coronal microleakage was evaluated using a fluid transport system. The movement of an air bubble in a capillary glass tube connected to the apex of the experimental root section was measured over 5-min periods. Measurements were performed four times for each specimen and the mean values recorded. ANOVA and Duncan's test were performed. The positive control group had the highest values of microleakage. Amongst experimental groups, the highest values of microleakage occurred in the group with the posts cemented with Harvard cement, followed by Fuji PLUS and Variolink II cements. Groups with Fuji PLUS, Variolink II and the negative control group had significantly (P < 0.00001) less microleakage compared with the Harvard cement group and the positive control group. Canals with Glassix posts cemented with Variolink II and Fuji PLUS cement had the least leakage when assessed using a fluid transport system.

  11. Can the use of deactivated glass fibre filters eliminate sorption artefacts associated with active air sampling of perfluorooctanoic acid?

    PubMed

    Johansson, Jana H; Berger, Urs; Cousins, Ian T

    2017-05-01

    Experimental work was undertaken to test whether gaseous perfluorooctanoic acid (PFOA) sorbs to glass fibre filters (GFFs) during air sampling, causing an incorrect measure of the gas-particle equilibrium distribution. Furthermore, tests were performed to investigate whether deactivation by siliconisation prevents sorption of gaseous PFOA to filter materials. An apparatus was constructed to closely simulate a high-volume air sampler, although with additional features allowing introduction of gaseous test compounds into an air stream stripped from particles. The set-up enabled investigation of the sorption of gaseous test compounds to filter media, eliminating any contribution from particles. Experiments were performed under ambient outdoor air conditions at environmentally relevant analyte concentrations. The results demonstrate that gaseous PFOA sorbs to GFFs, but that breakthrough of gaseous PFOA on the GFFs occurs at trace-level loadings. This indicates that during high volume air sampling, filters do not quantitatively capture all the PFOA in the sampled air. Experiments with siliconised GFFs showed that this filter pre-treatment reduced the sorption of gaseous PFOA, but that sorption still occurred at environmentally relevant air concentrations. We conclude that deactivation of GFFs does not allow for the separation of gaseous and particle bound perfluorinated carboxylic acids (PFCAs) during active air sampling. Consequently, the well-recognised theory that PFCAs do not prevail as gaseous species in the atmosphere may be based on biased measurements. Caution should be taken to ensure that this artefact will not bias the conclusions of future field studies.

  12. Improved dimensional stability with bioactive glass fibre skeleton in poly(lactide-co-glycolide) porous scaffolds for tissue engineering.

    PubMed

    Haaparanta, Anne-Marie; Uppstu, Peter; Hannula, Markus; Ellä, Ville; Rosling, Ari; Kellomäki, Minna

    2015-11-01

    Bone tissue engineering requires highly porous three-dimensional (3D) scaffolds with preferable osteoconductive properties, controlled degradation, and good dimensional stability. In this study, highly porous 3D poly(d,l-lactide-co-glycolide) (PLGA) - bioactive glass (BG) composites (PLGA/BG) were manufactured by combining highly porous 3D fibrous BG mesh skeleton with porous PLGA in a freeze-drying process. The 3D structure of the scaffolds was investigated as well as in vitro hydrolytic degradation for 10weeks. The effect of BG on the dimensional stability, scaffold composition, pore structure, and degradation behaviour of the scaffolds was evaluated. The composites showed superior pore structure as the BG fibres inhibited shrinkage of the scaffolds. The BG was also shown to buffer the acidic degradation products of PLGA. These results demonstrate the potential of these PLGA/BG composites for bone tissue engineering, but the ability of this kind of PLGA/BG composites to promote bone regeneration will be studied in forthcoming in vivo studies.

  13. Interfibre Failure Characterisation of Unidirectional and Triax Glass Fibre Non-Crimp Fabric Reinforced Epoxy Laminates

    NASA Astrophysics Data System (ADS)

    Laustsen, S.; Lund, E.; Kühlmeier, L.; Thomsen, O. T.

    2015-02-01

    The in-plane failure envelopes of unidirectional (UD) laminae in a UD and a Triax (0°, ±45°) laminate configuration have been investigated. The two laminate configurations have been characterised by testing off-axis specimens in uniaxial tension and compression at different angles relative to the fibre direction and further by Iosipescu shear tests. Strain gauge and Digital Image Correlation (DIC) measurements were used to measure the deformation states during loading, and to record the stress-strain responses to identify the initiation of failure and investigate the heterogeneity of the material and possible parasitic effects. A novel analysis methodology to determine the so-called `failure initiation strength' based on the second derivative of the stresses with respect to the strains has been adopted. The experimentally determined `failure initiation stresses' were compared with predictions from the commonly applied Maximum Stress, Tsai-Wu, and Puck failure criteria. From this work, a thorough comparison of the UD and Triax failure envelopes has been facilitated. It is shown that failure prediction for the Triax laminate based on the failure envelope derived from UD lamina tests may be too conservative in comparison with fitting a failure criterion directly to the Triax laminate test data. The latter approach implies that the Triax laminate is considered as a single lamina with homogenised properties, which in principle violates the theoretical background of the considered failure criteria, since these are established to predict failure for a UD lamina. However, the simple homogenisation is shown to be a useful design oriented approach for providing a simple estimation of the onset of failure in laminate configurations composed of e.g., multiple layers of Triax. Thus, a reliable and efficient approach is offered for the structural integrity assessment, which takes the non-crimp fabric configurations directly or `as delivered' into account.

  14. The influence of coupling agents on mechanical property retention and long-term cytocompatibility of phosphate glass fibre reinforced PLA composites.

    PubMed

    Hasan, M S; Ahmed, I; Parsons, A J; Walker, G S; Scotchford, C A

    2013-12-01

    Completely resorbable composites are an attractive alternative for metallic bone-fracture fixation devices. However, failure of their interfacial integrity within aqueous environments, which can lead to a rapid loss of overall mechanical properties, has been reported in the literature. In this study coupling agents were investigated for phosphate glass fibre reinforced poly(lactic acid) composites. Three coupling agents with varying wettability were employed to improve initial mechanical properties and their retention in vitro via improvement of the interfacial bond between polymer matrix and fibres. Coupling agents were grafted onto the glass fibres by dip-coating in coupling agent solution at optimised concentrations. Three-aminopropyltriethoxy silane and sorbitol ended PLA oligomer treatments improved the initial flexural properties (27% strength with APS and 17% modulus via SPLA treatment) of the composites and 3-aminopropyltriethoxy silane and hexamethylene diisocyanate (HDI) treatments also decreased the loss of flexural strength and modulus during degradation. HDI treated samples retained 57.2% and 64.7% of their initial strength and modulus, respectively compared to control where only 34% of initial strength and 52% of initial modulus was retained after 28 days of degradation in PBS solution. Initial improvements in flexural properties were associated with improved shear bond strength at the interface due to covalent bonding between the glass fibres and polymer matrix provided by the coupling agents. Delay in mechanical property loss with degradation was suggested to be due to the hydrophobicity at the interface, which could have hindered the interfacial integrity loss and consequently loss of mechanical integrity of the composites. All coupling agent treated and control composites were tested for cytocompatibility using a primary human osteoblast cell line. A comparable response to the control, in terms of cell adhesion, proliferation and differentiation

  15. Energy transfer in optical fibres

    SciTech Connect

    Biryukov, A S; Dianov, Evgenii M

    2007-04-30

    The possibility of energy transfer over long distances in the form of laser radiation propagating in dielectric optical fibres is discussed. Because nonlinear-optical phenomena in glasses prevent the transfer of high radiation powers in standard two-layer fibres, the outlook for this transfer is associated with the development of the technology of microstructure fibres with a hollow core and with further progress in the development of high-power fibre lasers. (optical fibres)

  16. Landfill Methane

    USDA-ARS?s Scientific Manuscript database

    Landfill methane (CH4) accounts for approximately 1.3% (0.6 Gt) of global anthropogenic greenhouse gas emissions relative to total emissions from all sectors of about 49 Gt CO2-eq yr-1. For countries with a history of controlled landfilling, landfills can be one of the larger national sources of ant...

  17. Effect of adhesive system type and root region on the push-out bond strength of glass-fibre posts to radicular dentine.

    PubMed

    Onay, E O; Korkmaz, Y; Kiremitci, A

    2010-04-01

    To compare interfacial strength in different thirds of the root canal amongst glass-fibre posts luted with four different adhesive luting agents. A total of 44 extracted human single-rooted teeth were randomly divided in four groups and restored using glass-fibre posts and the following luting agents: All Bond SE/Duo-Link (ABSE), All Bond 3/Duo-Link (AB3), BisCem (BC), Clearfil ED primer II/Clearfil Esthetic Cement (CLF). One week after luting, the samples were thermocycled in water, and then embedded in acrylic resin. Three sections (cervical, middle and apical) of 2 mm thickness were prepared from each specimen, and the post in each section was subjected to a push-out test. One additional specimen for each group was prepared for scanning electron microscopy analysis and the bonding effectiveness to dentine was assessed. The data were analysed using the Kolmogorov-Smirnov test, two-way anova, one-way anova, and the Scheffe test (P < 0.05). The push-out bond strength values for BC and ABSE were not significantly different (P > 0.05), but both were significantly higher than the means for AB3 and CLF (P < 0.05) in the cervical and middle regions. The same trend was observed in the apical region, except for the AB3 and ABSE which were not significantly different (P > 0.05) from each other. There were significant differences in bond strength amongst root thirds, with a reduction in values from the cervical to apical third (P < 0.05). The use of BisCem and All Bond SE/Duo-Link combination with their simplified application procedures may be considered an alternative to the currently used systems for luting glass-fibre posts in root canal.

  18. Fibres get functional

    NASA Astrophysics Data System (ADS)

    Graham-Rowe, Duncan

    2011-02-01

    New forms of advanced optical fibres featuring exotic glasses, carefully designed microstructures and cores that are either hollow, fluidic, semiconductor or piezoelectric are giving light guides a new lease of life, reports Duncan Graham-Rowe.

  19. Fibre gratings and their applications

    SciTech Connect

    Vasil'ev, Sergei A; Medvedkov, O I; Korolev, I G; Bozhkov, A S; Kurkov, Andrei S; Dianov, Evgenii M

    2005-12-31

    A brief review is given of the state of the art in the research on the photosensitivity of fibres and photoinduced fibre gratings. The most important properties of fibre gratings are considered and the main methods of their production and their applications are discussed. The photosensitive compositions of silica glasses are presented and methods for increasing their photosensitivity are indicated. (review)

  20. Quasi-static Load Sharing Model in the Case of Moulded Glass Fibre Reinforced Polyamide 6 Gears

    NASA Astrophysics Data System (ADS)

    Cathelin, Julien; Guingand, Michèle; de Vaujany, Jean-Pierre; Chazeau, Laurent; Adrien, Jérôme

    2015-08-01

    This paper presents a fast and efficient computational method to predict the mechanical behaviour of plastic cylindrical gears made of fibre reinforced polyamide 6. Based on this method, an investigation on the relation between the fibre orientation and the gear behaviour is done. The numerical method uses a viscoelastic model accounting for the temperature, humidity and rotational speed dependence of the gear. This model is developed under the assumption that the material is stressed in its linear domain. The method is performed in three steps: the first one consists of defining the fibre orientation from simulation and experimental results. The second step characterises the viscoelastic behaviour of the material. The third step consists in calculating the load sharing with local meshing, which integrates the viscoelastic model over the entire surface of the tooth. This model permits computation of the load sharing between instantaneously engaged teeth and provides results such as contact pressure, tooth root stress and transmission error. Three fibre orientation models with an increasing complexity are compared. Simulation results show a limited influence of the fibre orientation on the contact pressure and tooth root stress, nevertheless difference up to 10 % are observed on the transmission error amplitude.

  1. Review of doped silica glass optical fibre: their TL properties and potential applications in radiation therapy dosimetry.

    PubMed

    Bradley, D A; Hugtenburg, R P; Nisbet, A; Abdul Rahman, Ahmad Taufek; Issa, Fatma; Mohd Noor, Noramaliza; Alalawi, Amani

    2012-12-01

    Review is made of dosimetric studies of Ge-doped SiO(2) telecommunication fibre as a 1-D thermoluminescence (TL) system for therapeutic applications. To-date, the response of these fibres has been investigated for UV sources, superficial X-ray beam therapy facilities, a synchrotron microbeam facility, electron linear accelerators, protons, neutrons and alpha particles, covering the energy range from a few eV to several MeV. Dosimetric characteristics include, reproducibility, fading, dose response, reciprocity between TL yield and dose-rate and energy dependence. The fibres produce a flat response to fixed photon and electron doses to within better than 3% of the mean TL distribution. Irradiated Ge-doped SiO(2) optical fibres show limited signal fading, with an average loss of TL signal of ~0.4% per day. In terms of dose response, Ge-doped SiO(2) optical fibres have been shown to provide linearity to x and electron doses, from a fraction of 1 Gy up to 2 kGy. The dosimeters have also been used in measuring photoelectron generation from iodinated contrast media; TL yields being some 60% greater in the presence of iodine than in its absence. The review is accompanied by previously unpublished data. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Sulphur-doped silica fibres

    SciTech Connect

    Gerasimova, V I; Rybaltovskii, A O; Chernov, P V; Mashinsky, V M; Sazhin, O D; Medvedkov, O I; Rybaltovsky, A A; Khrapko, R R

    2003-01-31

    An optical fibre with low optical losses is manufactured from a sulphur-doped quartz glass. Optical absorption spectra are measured for various parts of the fibre core. Most of the bands of these spectra are assigned to oxygen-deficient centres and colour centres containing sulphur atoms. The photosensitivity of glasses exposed to laser radiation at wavelengths of 193 and 244 nm is investigated to estimate the possibility of their application for producing photorefracting devices. A Bragg grating of the refractive index with {Delta}n = 7.8 x 10{sup -4} is written in a sulphur-doped silica fibre. (fibre optics)

  3. Evaluation of Thrust force in Drilling Woven roving Glass fibre reinforced Aluminium Sandwich laminates with TiAlN coated drill using Taguchi analysis

    NASA Astrophysics Data System (ADS)

    Ramya Devi, G.; Palanikumar, K.

    2017-05-01

    TiAlN is a high-performance coating which outshines in coarse and hard-to-machine materials like cast iron, aluminium alloys, tool steels, and nickel alloys. This paper presents the prediction and evaluation of thrust force and Torque in drilling of Woven roving Glass Fibre Reinforced Plastic and Aluminium sandwich laminate. The Prediction is based on Taguchi method. The experimental results specify that the feed rate and the drill diameter are the most significant factors affecting the thrust force, while the feed rate and spindle speed contribute the most to the surface roughness. In this study, the objective was to establish a correlation between the feed rate, spindle speed and drill diameter with the induced thrust force and Torque in drilling sandwich laminate.

  4. Packaging and Mounting of In-Fibre Bragg Grating Arrays for Structural Health Monitoring of Large Structures

    DTIC Science & Technology

    2010-10-01

    33 Abbreviations CFRP Carbon Fibre Reinforced Polymer FBG Fibre Bragg Grating FGI Fiberglass International FO... Fibre Optic FOS Fibre Optic Sensor GFRP Glass Fibre Reinforced Polymer HDPE High Density Polyethylene LED Light Emitting Diode MHC Mine Hunter...subsequent paragraphs. An operational loads monitoring system for wind turbine blades was demonstrated [7] using FBGs surface-mounted onto glass fibre

  5. Bismuth-ring-doped fibres

    SciTech Connect

    Zlenko, Aleksandr S; Dvoirin, Vladislav V; Bogatyrev, Vladimir A; Firstov, Sergei V; Akhmetshin, Ural G

    2009-11-30

    A new process for bismuth doping of optical fibres is proposed in which the dopant is introduced into a thin layer surrounding the fibre core. This enables bismuth stabilisation in the silica glass, with no limitations on the core composition. In particular, the GeO{sub 2} content of the fibre core in this study is 16 mol %. Spectroscopic characterisation of such fibres and optical gain measurements suggest that the proposed approach has considerable potential for laser applications. (optical fibres and fibreoptic sensors)

  6. Influence of Thermo-Oxidative Ageing on the Thermal and Dynamical Mechanical Properties of Long Glass Fibre-Reinforced Poly(Butylene Terephthalate) Composites Filled with DOPO

    PubMed Central

    Zhang, Daohai; He, Min; He, Weidi; Zhou, Ying; Qin, Shuhao; Yu, Jie

    2017-01-01

    In this work, the long glass fibre-reinforced poly(butylene terephthalate) (PBT) composites filled with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) were prepared by melt blending, and the influence of thermo-oxidative ageing on the static and dynamic mechanical properties, thermal behaviours and morphology of composites with different ageing time at 120 °C were investigated and analysed. The results showed that the mechanical properties decreased in the primary stage of ageing, while embrittlement occurs in the later period, and the crystallinity of PBT decreases first, and then recovers to some extent. The scanning electron microscopy (SEM) photos of the samples indicated that the obvious crack appeared on the sample surface and a deeper, broader crack occurred with a longer ageing time. The results of energy dispersive X-ray analysis (EDAX) proved the DOPO filler diffused to the sample surface by measuring the content of phosphorus. Thermal gravimetric analysis (TGA) curves showed that the thermal stabilities of composites increased with longer ageing time, as did the values of the limited oxygen index (LOI). Meanwhile, the results of dynamic mechanical analysis (DMA) indicated that the glass transition temperature shifted to a higher temperature after ageing due to the effect of crosslinking, and both the crosslinking and degradation of PBT molecular chains act as the main factors in the whole process of thermo-oxidative ageing. PMID:28772860

  7. Influence of Thermo-Oxidative Ageing on the Thermal and Dynamical Mechanical Properties of Long Glass Fibre-Reinforced Poly(Butylene Terephthalate) Composites Filled with DOPO.

    PubMed

    Zhang, Daohai; He, Min; He, Weidi; Zhou, Ying; Qin, Shuhao; Yu, Jie

    2017-05-04

    In this work, the long glass fibre-reinforced poly(butylene terephthalate) (PBT) composites filled with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) were prepared by melt blending, and the influence of thermo-oxidative ageing on the static and dynamic mechanical properties, thermal behaviours and morphology of composites with different ageing time at 120 °C were investigated and analysed. The results showed that the mechanical properties decreased in the primary stage of ageing, while embrittlement occurs in the later period, and the crystallinity of PBT decreases first, and then recovers to some extent. The scanning electron microscopy (SEM) photos of the samples indicated that the obvious crack appeared on the sample surface and a deeper, broader crack occurred with a longer ageing time. The results of energy dispersive X-ray analysis (EDAX) proved the DOPO filler diffused to the sample surface by measuring the content of phosphorus. Thermal gravimetric analysis (TGA) curves showed that the thermal stabilities of composites increased with longer ageing time, as did the values of the limited oxygen index (LOI). Meanwhile, the results of dynamic mechanical analysis (DMA) indicated that the glass transition temperature shifted to a higher temperature after ageing due to the effect of crosslinking, and both the crosslinking and degradation of PBT molecular chains act as the main factors in the whole process of thermo-oxidative ageing.

  8. Dispersion and guidance characteristics of microstructured 68TeO{sub 2} - 22WO{sub 3} - 8La{sub 2}O{sub 3} - 2Bi{sub 2}O{sub 3} glass fibres for supercontinuum generation

    SciTech Connect

    Yatsenko, Yu P; Nazaryants, V O; Kosolapov, A F; Astapovich, M S; Plotnichenko, V G; Dianov, Evgenii M; Moiseev, A N; Churbanov, M F; Dorofeev, V V; Chilyasov, A V; Snopatin, G E

    2010-08-27

    We report the preparation of a high-purity optical-quality four-component glass of composition 68TeO{sub 2} - 22WO{sub 3} - 8La{sub 2}O{sub 3} - 2Bi{sub 2}O{sub 3}, containing (2.7{+-}0.5)x10{sup -5} mol % OH groups. Its refractive index has been determined in the range 0.9 - 5.45 {mu}m using interference refractometry. The data are used to assess the dispersion and guidance characteristics of microstructured optical fibres potentially attractive for supercontinuum generation in the range 1 - 5 {mu}m (optical fibres)

  9. Sea Water Ageing of Composites for Ocean Energy Conversion Systems: Influence of Glass Fibre Type on Static Behaviour

    NASA Astrophysics Data System (ADS)

    Boisseau, Amélie; Davies, Peter; Thiebaud, Frédéric

    2012-06-01

    Composite material components will be an essential part of ocean energy recovery devices, and their long term durability in sea water must be guaranteed. Despite extensive experience for boat structures and wind turbines few data exist to design structures subjected to a combination of mechanical loads and sea water immersion. This paper presents the first results from an experimental study, performed jointly with fibre manufacturers, and a resin supplier, to fill this gap. The experimental study is completed by numerical modelling to simulate the coupling between water absorption and mechanical behaviour. Sea water ageing is shown to result in a drop in quasi-static mechanical properties and a change in flexural mode from compression to tension at longer ageing times, which is consistent with results from the numerical simulations.

  10. Testing and simulation of a polypropylene-glass fibre reinforced woven composite on a wide range of strain-rates

    NASA Astrophysics Data System (ADS)

    Martin, A.; Othman, R.; Rozycki, P.

    2012-08-01

    Medium costs composites materials are good candidates to develop lightweight and economical shock absorber for the next generation of cars. In this context we are interested in characterising and modelling of Twintex a long glass fiber reinforced polypropylene. Testing will be carried with a standard tensile rig and an original layout using a crossbow/Hopkinson rig. A special attention is made to compression behaviour identification, often neglected but critical for crash absorber behaviour. The model will be checked on the testing specimen and its validity will be discussed.

  11. Shear compression testing of glass-fibre steel specimens after 4K reactor irradiation: Present status and facility upgrade

    SciTech Connect

    Gerstenberg, H.; Kraehling, E.; Katheder, H.

    1997-06-01

    The shear strengths of various fibre reinforced resins being promising candidate insulators for superconducting coils to be used tinder a strong radiation load, e.g. in future fusion reactors were investigated prior and subsequent to reactor in-core irradiation at liquid helium temperature. A large number of sandwich-like (steel-bonded insulation-steel) specimens representing a widespread variety of materials and preparation techniques was exposed to irradiation doses of up to 5 x 10{sup 7} Gy in form of fast neutrons and {gamma}-radiation. In a systematic study several experimental parameters including irradiation dose, postirradiation storage temperature and measuring temperature were varied before the determination of the ultimate shear strength. The results obtained from the different tested materials are compared. In addition an upgrade of the in-situ test rig installed at the Munich research reactor is presented, which allows combined shear/compression loading of low temperature irradiated specimens and provides a doubling of the testing rate.

  12. In vitro and in vivo evaluations of nano-hydroxyapatite/polyamide 66/glass fibre (n-HA/PA66/GF) as a novel bioactive bone screw.

    PubMed

    Su, Bao; Peng, Xiaohua; Jiang, Dianming; Wu, Jun; Qiao, Bo; Li, Weichao; Qi, Xiaotong

    2013-01-01

    In this study, we prepared nano-hydroxyapatite/polyamide 66/glass fibre (n-HA/PA66/GF) bioactive bone screws. The microstructure, morphology and coating of the screws were characterised, and the adhesion, proliferation and viability of MC3T3-E1 cells on n-HA/PA66/GF scaffolds were determined using scanning electron microscope, CCK-8 assays and cellular immunofluorescence analysis. The results confirmed that n-HA/PA66/GF scaffolds were biocompatible and had no negative effect on MC3T3-E1 cells in vitro. To investigate the in vivo biocompatibility, internal fixation properties and osteogenesis of the bioactive screws, both n-HA/PA66/GF screws and metallic screws were used to repair intercondylar femur fractures in dogs. General photography, CT examination, micro-CT examination, histological staining and biomechanical assays were performed at 4, 8, 12 and 24 weeks after operation. The n-HA/PA66/GF screws exhibited good biocompatibility, high mechanical strength and extensive osteogenesis in the host bone. Moreover, 24 weeks after implantation, the maximum push-out load of the bioactive screws was greater than that of the metallic screws. As shown by their good cytocompatibility, excellent biomechanical strength and fast formation and ingrowth of new bone, n-HA/PA66/GF screws are thus suitable for orthopaedic clinical applications.

  13. The Effects of Thermophysical Properties and Environmental Conditions on Fire Performance of Intumescent Coatings on Glass Fibre-Reinforced Epoxy Composites

    PubMed Central

    Kandola, Baljinder K.; Luangtriratana, Piyanuch; Duquesne, Sophie; Bourbigot, Serge

    2015-01-01

    Intumescent coatings are commonly used as passive fire protection systems for steel structures. The purpose of this work is to explore whether these can also be used effectively on glass fibre-reinforced epoxy (GRE) composites, considering the flammability of the composites compared to non-flammable steel substrate. The thermal barrier and reaction-to-fire properties of three commercial intumescent coatings on GRE composites have been studied using a cone calorimeter. Their thermophysical properties in terms of heating rate and/or temperature dependent char expansion ratios and thermal conductivities have been measured and correlated. It has been suggested that these two parameters can be used to design coatings to protect composite laminates of defined thicknesses for specified periods of time. The durability of the coatings to water absorption, peeling, impact, and flexural loading were also studied. A strong adhesion between all types of coatings and the substrate was observed. Water soaking had a little effect on the fire performance of epoxy based coatings. All types of 1 mm thick coatings on GRE helped in retaining ~90% of the flexural property after 2 min exposure to 50 kW/m2 heat flux whereas the uncoated laminate underwent severe delamination and loss in structural integrity after 1 min. PMID:28793500

  14. The Effects of Thermophysical Properties and Environmental Conditions on Fire Performance of Intumescent Coatings on Glass Fibre-Reinforced Epoxy Composites.

    PubMed

    Kandola, Baljinder K; Luangtriratana, Piyanuch; Duquesne, Sophie; Bourbigot, Serge

    2015-08-11

    Intumescent coatings are commonly used as passive fire protection systems for steel structures. The purpose of this work is to explore whether these can also be used effectively on glass fibre-reinforced epoxy (GRE) composites, considering the flammability of the composites compared to non-flammable steel substrate. The thermal barrier and reaction-to-fire properties of three commercial intumescent coatings on GRE composites have been studied using a cone calorimeter. Their thermophysical properties in terms of heating rate and/or temperature dependent char expansion ratios and thermal conductivities have been measured and correlated. It has been suggested that these two parameters can be used to design coatings to protect composite laminates of defined thicknesses for specified periods of time. The durability of the coatings to water absorption, peeling, impact, and flexural loading were also studied. A strong adhesion between all types of coatings and the substrate was observed. Water soaking had a little effect on the fire performance of epoxy based coatings. All types of 1 mm thick coatings on GRE helped in retaining ~90% of the flexural property after 2 min exposure to 50 kW/m² heat flux whereas the uncoated laminate underwent severe delamination and loss in structural integrity after 1 min.

  15. In Vitro and In Vivo Evaluations of Nano-Hydroxyapatite/Polyamide 66/Glass Fibre (n-HA/PA66/GF) as a Novel Bioactive Bone Screw

    PubMed Central

    Su, Bao; Peng, Xiaohua; Jiang, Dianming; Wu, Jun; Qiao, Bo; Li, Weichao; Qi, Xiaotong

    2013-01-01

    In this study, we prepared nano-hydroxyapatite/polyamide 66/glass fibre (n-HA/PA66/GF) bioactive bone screws. The microstructure, morphology and coating of the screws were characterised, and the adhesion, proliferation and viability of MC3T3-E1 cells on n-HA/PA66/GF scaffolds were determined using scanning electron microscope, CCK-8 assays and cellular immunofluorescence analysis. The results confirmed that n-HA/PA66/GF scaffolds were biocompatible and had no negative effect on MC3T3-E1 cells in vitro. To investigate the in vivo biocompatibility, internal fixation properties and osteogenesis of the bioactive screws, both n-HA/PA66/GF screws and metallic screws were used to repair intercondylar femur fractures in dogs. General photography, CT examination, micro-CT examination, histological staining and biomechanical assays were performed at 4, 8, 12 and 24 weeks after operation. The n-HA/PA66/GF screws exhibited good biocompatibility, high mechanical strength and extensive osteogenesis in the host bone. Moreover, 24 weeks after implantation, the maximum push-out load of the bioactive screws was greater than that of the metallic screws. As shown by their good cytocompatibility, excellent biomechanical strength and fast formation and ingrowth of new bone, n-HA/PA66/GF screws are thus suitable for orthopaedic clinical applications. PMID:23861888

  16. Resonance Tests on Glass Reinforced Plastic Composite Panels.

    DTIC Science & Technology

    1981-04-01

    glass -- fibre woven roving and glass - fibre chopped strand mat. BP Cellobond A2785-CV resin was used to bond the glass fibre layers to the foam. A rib was...foam slabs were filled with putty. The differences between the panels were the number of layers of glass fibre used on each side, the density of the...ORGANISATION AERONAUTICAL RESEARCH LABORATORIES MELBOURNE, VICTORIA Structures Technical Memorandum 329 RESONANCE TESTS O GLASS REINFORCED PLASTIC

  17. Cleaner Landfills

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Osmotek, Inc. developed the Direct Osmosis treatment system through SBIR funding from Ames Research Center. Using technology originally developed for flight aboard the Space Station, the company brought it to their commercial water purification treatment system, Direct Osmosis. This water purification system uses a direct osmosis process followed by a reverse osmosis treatment. Because the product extracts water from a waste product, Osmotek is marketing the unit for use in landfills. The system can treat leachate (toxic chemicals leached into a water source), by filtering the water and leaving behind the leahcate. The leachate then becomes solidified into substance that can not seep into water.

  18. Evaluation of a short glass fibre-reinforced tube as a model for cat femur for biomechanical testing of orthopaedic implants.

    PubMed

    Gibson, T W G; Moens, N M M; Runciman, R J; Holmberg, D L

    2008-01-01

    The biomechanical testing of tubes made of third generation short glass fibre-reinforced (SGFR) material approximating cat femurs was performed in order to determine their suitability as cat femur surrogates for the biomechanical testing of orthopaedic implants. The tubes were tested in compression, three-point bending, notch testing, and screw pullout. Thin walled (B1-tubes) had a 13% lower maximum load to failure, a 19% higher maximum strength and a 13% lower elastic modulus compared to cat femurs tested in compression. B1-tubes maximum load to failure in three-point bending and screw pullout strength were considerably lower compared to cat femurs (29% and 63%, respectively). Notch testing was not performed on B1-tubes due to low bending strength. Thicker walled (B2-tubes) had a 23% higher maximum load to failure, a 10% higher maximum strength and a 21% lower elastic modulus compared to cat femurs tested in compression. The comparison of B2-tubes and cat femurs in three-point bending revealed a 7% increase in maximum load to failure for the B2-tubes. Drilled B2-tubes (notch testing) were weaker with a 30% lower load to failure compared to cat femurs. A screw pullout comparison of B2-tubes and cat femurs revealed a 2% increase in maximum load to failure for the B2-tubes. These tubes were intended to provide a model as a suitable surrogate for cat femurs for testing the bending strength of various orthopaedic constructs involving plates and screws. Testing revealed that third generation SGFR tubes were not suitable for these purposes and emphasizes the need to carefully evaluate the suitability of any model.

  19. Pilot study of unidirectional E-glass fibre-reinforced composite resin splints: up to 4.5-year clinical follow-up.

    PubMed

    Kumbuloglu, Ovul; Saracoglu, Ahmet; Ozcan, Mutlu

    2011-12-01

    This prospective clinical pilot study evaluated the performance of fibre-reinforced-composite resin (FRC) splints on mandibular anterior teeth. Between June-2003 and January-2008, 19 patients (7 females, 12 males, 45-72 years old) from a group of consecutive patients who completed periodontal therapy received E-glass FRC splints (everStick Perio, StickTech) in combination with two types of flowable and restorative resin-composites (Filtek Flow, Filtek Supreme, n=11; Tetric Flow, Tetric-Ceram, n=8). Only patients with vital teeth, presenting mobility of grade 3, having at least one canine with no mobility on both sides of the dental arch were assigned for a splint therapy. The patients were recalled for periodical follow-up controls first at 6 months and thereafter annually. The evaluation protocol involved technical failures [chipping, debonding or fracture (tooth/restoration)] and biological failures (caries)]. Periodontal pocket depth (PPD) and clinical attachment level (CAL) were measured 6 months after splinting and annually. Six sites were measured for each natural tooth at the mesiobuccal, buccal, distobuccal, distolingual, lingual and mesiolingual sites. All splints were applied from canine to canine in the mandible. In total, 5 recalls were performed and no drop-out was experienced. One partial debonding of the FRC splint with Tetric Flow/Tetric-Ceram combination was observed after 40 months. No caries was found around any of the splints and no teeth had to be extracted until the final follow up. The splinted teeth were found to be vital in the vitality tests. Overall survival rate was 94.8% (Kaplan-Meier). The survival rate was not significantly affected by the composite type (Filtek-Flow/Filtek Supreme: 100%, Tetric Flow/Tetric Ceram: 96% (p=0.92) [Kaplan-Meier, Log Rank (Mantel-Cox) (CI=95%)]. Hazard ratio for Tetric Flow/Tetric Ceram group was 0.05 (95% CI) and for Filtek Flow/Filtek Supreme group 0.00 (95% CI). Whilst overall PPD measurements of the

  20. Eco-efficient waste glass recycling: Integrated waste management and green product development through LCA

    SciTech Connect

    Blengini, Gian Andrea; Busto, Mirko; Fantoni, Moris; Fino, Debora

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer A new eco-efficient recycling route for post-consumer waste glass was implemented. Black-Right-Pointing-Pointer Integrated waste management and industrial production are crucial to green products. Black-Right-Pointing-Pointer Most of the waste glass rejects are sent back to the glass industry. Black-Right-Pointing-Pointer Recovered co-products give more environmental gains than does avoided landfill. Black-Right-Pointing-Pointer Energy intensive recycling must be limited to waste that cannot be closed-loop recycled. - Abstract: As part of the EU Life + NOVEDI project, a new eco-efficient recycling route has been implemented to maximise resources and energy recovery from post-consumer waste glass, through integrated waste management and industrial production. Life cycle assessment (LCA) has been used to identify engineering solutions to sustainability during the development of green building products. The new process and the related LCA are framed within a meaningful case of industrial symbiosis, where multiple waste streams are utilised in a multi-output industrial process. The input is a mix of rejected waste glass from conventional container glass recycling and waste special glass such as monitor glass, bulbs and glass fibres. The green building product is a recycled foam glass (RFG) to be used in high efficiency thermally insulating and lightweight concrete. The environmental gains have been contrasted against induced impacts and improvements have been proposed. Recovered co-products, such as glass fragments/powders, plastics and metals, correspond to environmental gains that are higher than those related to landfill avoidance, whereas the latter is cancelled due to increased transportation distances. In accordance to an eco-efficiency principle, it has been highlighted that recourse to highly energy intensive recycling should be limited to waste that cannot be closed-loop recycled.

  1. Dietary fibre.

    PubMed

    Escudero Alvarez, E; González Sánchez, P

    2006-05-01

    Currently and after 30 years of research, dietary fibre is part of what is considered a healthy diet. There is no single definition yet comprising the different components of dietary fibre and its functions. The main factors of fibre are complex carbohydrates and lignin, although new products may be included in the future within the concept of fibre. Dietary fibres reach the large bowel and are attacked by colonic microflora, yielding short chain fatty acids, hydrogen, carbon dioxide, and methane as fermentation products. Short chain fatty acids represent a way of recovering energy and they are also implicated in other beneficial functions for the human organism. Although there are no yet conclusive data on recommendations of different types of fibre, it is still appropriate to indicate a diet providing 20-35 g/day of fibre from different sources. There is a consensus to recommend a mixture of fibres or fibre like soybean polysaccharide for constipation. There are few conclusive data, still, on the benefit of fibre on prevention of colorectal cancer and cardiovascular disease. However, a fibre-rich diet is recommended from early years of life since it is often associated to a lifestyle that in the long term helps controlling other risk factors.

  2. Landfill Gas Effects on Evapotranspirative Landfill Covers

    NASA Astrophysics Data System (ADS)

    Plummer, M. A.; Mattson, E.; Ankeny, M.; Kelsey, J.

    2005-05-01

    The performance of an evapotranspirative landfill cover can be adversely affected by transport of landfill gases to the plant root zone. Healthy plant communities are critical to the success and effectiveness of these vegetated landfill covers. Poor vegetative cover can result in reduced transpiration, increased percolation, and increased erosion regardless of the thickness of the cover. Visual inspections of landfill covers indicate that vegetation-free areas are not uncommon at municipal waste landfills. Data from soil profiles beneath these areas suggest that anaerobic conditions in the plant-rooting zone are controlling plant distribution. On the same landfill, aerobic conditions exist at similar depths beneath well-vegetated areas. The movement of methane and carbon dioxide, generated by degradation of organic wastes, into the overlying soil cover displaces oxygen in the root zone. Monitoring data from landfills in semi-arid areas indicate that barometric pumping can result in hours of anaerobic conditions in the root zone. Microbial consumption of oxygen in the root zone reduces the amount of oxygen available for plant root respiration but consumption of oxygen and methane also produce water as a reaction byproduct. This biogenic water production can be on the order of centimeters of water per year which, while increasing water availability, also has a negative feedback on transport of landfill gases through the cover. Accounting for these processes can improve evapotranspirative landfill cover design at other sites.

  3. Material flow-based economic assessment of landfill mining processes.

    PubMed

    Kieckhäfer, Karsten; Breitenstein, Anna; Spengler, Thomas S

    2017-02-01

    This paper provides an economic assessment of alternative processes for landfill mining compared to landfill aftercare with the goal of assisting landfill operators with the decision to choose between the two alternatives. A material flow-based assessment approach is developed and applied to a landfill in Germany. In addition to landfill aftercare, six alternative landfill mining processes are considered. These range from simple approaches where most of the material is incinerated or landfilled again to sophisticated technology combinations that allow for recovering highly differentiated products such as metals, plastics, glass, recycling sand, and gravel. For the alternatives, the net present value of all relevant cash flows associated with plant installation and operation, supply, recycling, and disposal of material flows, recovery of land and landfill airspace, as well as landfill closure and aftercare is computed with an extensive sensitivity analyses. The economic performance of landfill mining processes is found to be significantly influenced by the prices of thermal treatment (waste incineration as well as refuse-derived fuels incineration plant) and recovered land or airspace. The results indicate that the simple process alternatives have the highest economic potential, which contradicts the aim of recovering most of the resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Fibres, Blood and Broken Glass

    ERIC Educational Resources Information Center

    Tomlinson, Bob; Peacock, Alan

    2005-01-01

    Crime Scene Investigators (CSIs) are the bridge between the police and forensic science specialists. Their job is to recover physical evidence from the scene of a crime, and try to make sense of it to interpret and explain what probably happened--which is just what scientists also do. They recover many things: objects, photographs of the crime…

  5. Fibres, Blood and Broken Glass

    ERIC Educational Resources Information Center

    Tomlinson, Bob; Peacock, Alan

    2005-01-01

    Crime Scene Investigators (CSIs) are the bridge between the police and forensic science specialists. Their job is to recover physical evidence from the scene of a crime, and try to make sense of it to interpret and explain what probably happened--which is just what scientists also do. They recover many things: objects, photographs of the crime…

  6. Landfill Gas Energy

    EPA Pesticide Factsheets

    This guide describes how local governments and communities can achieve energy, environmental, health, and economic benefits by using landfill gas (LFG) recovered from municipal solid waste landfills as a source of renewable energy.

  7. Landfill Gas Energy

    EPA Pesticide Factsheets

    This guide describes how local governments and communities can achieve energy, environmental, health, and economic benefits by using landfill gas (LFG) recovered from municipal solid waste landfills as a source of renewable energy.

  8. Learning from Landfills.

    ERIC Educational Resources Information Center

    Galus, Pamela

    2000-01-01

    Describes a project in which students developed an all-class laboratory activity called "The Decomposition of Organic and Inorganic Substances in a Landfill". Explores what conditions are necessary to facilitate decomposition in a landfill. (SAH)

  9. Learning from Landfills.

    ERIC Educational Resources Information Center

    Galus, Pamela

    2000-01-01

    Describes a project in which students developed an all-class laboratory activity called "The Decomposition of Organic and Inorganic Substances in a Landfill". Explores what conditions are necessary to facilitate decomposition in a landfill. (SAH)

  10. Polysiloxane optical fibres and fibre structures

    NASA Astrophysics Data System (ADS)

    Martincek, Ivan; Pudis, Dusan

    2016-12-01

    The polysiloxane fibres made of polysiloxanes such as polydimethylsiloxane (PDMS) and poly(dimethyl)(diphenil)siloxane (PDMDPS) can be attractive for different fibre applications and fibre structures. In this paper we describe the fabrication technological process of polysiloxane fibres and fibre structures integrated with conventional single-mode optical fibres. We present two-modes interferometer prepared from PDMS biconical optical fibre taper, PDMDPS optical fibre microloop interferometer and liquid microdroplet optical fibre interferometer. We achieved interesting optical properties all these fibre structures as was confirmed from the transmission characteristics what may be attractive for utilisation in various types of optical fibre sensors.

  11. Fibre Models

    NASA Astrophysics Data System (ADS)

    Herrmann, H. J.; Kun, F.

    2007-12-01

    Fibre models have been introduced as simple models to describe failure. They are based on the probability distribution of broken fibres. The load redistribution after a fibre yields can be global or local and the first case can often be solved analytically. We will present an interpolation between these the local and the global case and apply it to experimental situations like the compression of granular packings. Introducing viscoelastic fibres allows to describe the creep of wood. It is even possible to deal analytically with a gradual degradation of fibres and consider damage as well as healing. In this way Basquin's law of fatigue can be reproduced and new universalities concerning the histograms of bursts and waiting times can be uncovered.

  12. Eco-efficient waste glass recycling: Integrated waste management and green product development through LCA.

    PubMed

    Blengini, Gian Andrea; Busto, Mirko; Fantoni, Moris; Fino, Debora

    2012-05-01

    As part of the EU Life + NOVEDI project, a new eco-efficient recycling route has been implemented to maximise resources and energy recovery from post-consumer waste glass, through integrated waste management and industrial production. Life cycle assessment (LCA) has been used to identify engineering solutions to sustainability during the development of green building products. The new process and the related LCA are framed within a meaningful case of industrial symbiosis, where multiple waste streams are utilised in a multi-output industrial process. The input is a mix of rejected waste glass from conventional container glass recycling and waste special glass such as monitor glass, bulbs and glass fibres. The green building product is a recycled foam glass (RFG) to be used in high efficiency thermally insulating and lightweight concrete. The environmental gains have been contrasted against induced impacts and improvements have been proposed. Recovered co-products, such as glass fragments/powders, plastics and metals, correspond to environmental gains that are higher than those related to landfill avoidance, whereas the latter is cancelled due to increased transportation distances. In accordance to an eco-efficiency principle, it has been highlighted that recourse to highly energy intensive recycling should be limited to waste that cannot be closed-loop recycled.

  13. Fibre typing of intrafusal fibres

    PubMed Central

    Thornell, Lars-Eric; Carlsson, Lena; Eriksson, Per-Olof; Liu, Jing-Xia; Österlund, Catharina; Stål, Per; Pedrosa-Domellöf, Fatima

    2015-01-01

    The first descriptions of muscle spindles with intrafusal fibres containing striated myofibrils and nervous elements were given approximately 150 years ago. It took, however, another 100 years to establish the presence of two types of intrafusal muscle fibres: nuclear bag and nuclear chain fibres. The present paper highlights primarily the contribution of Robert Banks in fibre typing of intrafusal fibres: the confirmation of the principle of two types of nuclear bag fibres in mammalian spindles and the variation in occurrence of a dense M-band along the fibres. Furthermore, this paper summarizes how studies from the Umeå University group (Laboratory of Muscle Biology in the Department of Integrative Medical Biology) on fibre typing and the structure and composition of M-bands have contributed to the current understanding of muscle spindle complexity in adult humans as well as to muscle spindle development and effects of ageing. The variable molecular composition of the intrafusal sarcomeres with respect to myosin heavy chains and M-band proteins gives new perspectives on the role of the intrafusal myofibrils as stretch-activated sensors influencing tension/stiffness and signalling to nuclei. PMID:26179023

  14. The in vivo biological activity of ceramic fibres.

    PubMed

    Brown, R C; Hoskins, J A; Glass, L R

    1995-10-01

    The well-known health effects following exposure to amphibole asbestos have led to some concern about the potential for other fibrous materials to cause similar diseases. This paper presents a summary of some of the inhalation experiments conducted with ceramic fibres in both rats and hamsters at the Research and Consulting Company, Geneva. One ceramic fibre (designated RCF1) was tested in rats at four exposure levels, this fibre was also tested in hamsters. Three other fibres were only tested in rats at the highest level--30 mg m-3. The increased incidence of tumours in these experiments has been contrasted with the negative results obtained with glass or mineral wools. However, there is evidence that the ceramic fibres were longer than the glass fibres and that long ceramic fibres were retained in lung tissue to a greater extent. This is sufficient to explain the results without recourse to explanations based on chemical differences between fibres.

  15. Radiation-resistant erbium-doped silica fibre

    SciTech Connect

    Zotov, K V; Likhachev, M E; Tomashuk, A L; Bubnov, M M; Yashkov, M V; Gur'yanov, A N

    2007-10-31

    It is shown that the service life of erbium-doped fibres can be increased many times under conditions of an elevated radiation level by loading the fibre glass network with molecular hydrogen. Backdiffusion of hydrogen from the fibre in the process of its operation is virtually excluded for the fibre covered with a hermetic carbon coating. It is shown that this technique of fibre preparation allows one to slow down significantly degradation of the lasing properties of erbium fibres under the conditions characteristic of space applications. (special issue devoted to the 25th anniversary of the a.m. prokhorov general physics institute)

  16. Landfill bioreactor design and operation

    SciTech Connect

    Reinhart, D.R.; Townsend, T.

    1998-12-31

    Landfill Bioreactor Design and Operation covers the history and background of landfill technology, research studies of actual bioreactor landfills, expected leachate and gas yields, specific design criteria, operation guidelines, and reuse of landfill sites to avoid having to establish new sites. For anyone looking for an alternative to large, wasteful landfill sites, this book provides a practical alternative to the problem.

  17. Methods of Sensing Land Pollution from Sanitary Landfills

    NASA Technical Reports Server (NTRS)

    Nosanov, Myron Ellis; Bowerman, Frank R.

    1971-01-01

    Major cities are congested and large sites suitable for landfill development are limited. Methane and other gases are produced at most sanitary landfills and dumps. These gases may migrate horizontally and vertically and have caused fatalities. Monitoring these gases provides data bases for design and construction of safe buildings on and adjacent to landfills. Methods of monitoring include: (1) a portable combustible gas indicator; and (2) glass flasks valved to allow simultaneous exhaust of the flask and aspiration of the sample into the flask. Samples are drawn through tubing from probes as deep as twenty-five feet below the surface.

  18. Methods of Sensing Land Pollution from Sanitary Landfills

    NASA Technical Reports Server (NTRS)

    Nosanov, Myron Ellis; Bowerman, Frank R.

    1971-01-01

    Major cities are congested and large sites suitable for landfill development are limited. Methane and other gases are produced at most sanitary landfills and dumps. These gases may migrate horizontally and vertically and have caused fatalities. Monitoring these gases provides data bases for design and construction of safe buildings on and adjacent to landfills. Methods of monitoring include: (1) a portable combustible gas indicator; and (2) glass flasks valved to allow simultaneous exhaust of the flask and aspiration of the sample into the flask. Samples are drawn through tubing from probes as deep as twenty-five feet below the surface.

  19. Aerobic landfill bioreactor

    SciTech Connect

    Hudgins, M.P.; Bessette, B.J.; March, J.; McComb, S.T.

    2000-02-15

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120 F and 140 F in steady state.

  20. Landfill disposal systems

    PubMed Central

    Slimak, Karen M.

    1978-01-01

    The current status of landfill disposal of hazardous wastes in the United States is indicated by presenting descriptions of six operating landfills. These landfills illustrate the variety of techniques that exist in landfill disposal of hazardous wastes. Although some landfills more effectively isolate hazardous waste than others, all landfills must deal with the following problems. Leachate from hazardous waste landfills is generally highly polluted. Most landfills attempt to contain leachate at the site and prevent its discharge to surface or groundwaters. To retain leachate within a disposal area, subsurface barriers of materials such as concrete, asphalt, butyl rubber, vinyl, and clay are used. It is difficult to assure that these materials can seal a landfill indefinitely. When a subsurface barrier fails, the leachate enters the groundwater in a concentrated, narrow band which may bypass monitoring wells. Once a subsurface barrier has failed, repairs are time-consuming and costly, since the waste above the repair site may have to be removed. The central problem in landfill disposal is leachate control. Recent emphasis has been on developing subsurface barriers to contain the wastes and any leachate. Future emphasis should also be on techniques for removing water from hazardous wastes before they are placed in landfills, and on methods for preventing contact of the wastes with water during and after disposal operations. When leachate is eliminated, the problems of monitoring, and subsurface barrier failure and repair can be addressed, and a waste can be effectively isolated. A surface seal landfill design is recommended for maintaining the dry state of solid hazardous wastes and for controlling leachate. Any impervious liner is utilized over the top of the landfill to prevent surface water from seeping into the waste. The surface barrier is also the site where monitoring and maintenance activities are focused. Barrier failure can be detected by visual

  1. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John C; McComb, Scott T.

    2002-01-01

    The present invention includes a system of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  2. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John; McComb, Scott T.

    2000-01-01

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  3. Random distributed feedback fibre lasers

    NASA Astrophysics Data System (ADS)

    Turitsyn, Sergei K.; Babin, Sergey A.; Churkin, Dmitry V.; Vatnik, Ilya D.; Nikulin, Maxim; Podivilov, Evgenii V.

    2014-09-01

    The concept of random lasers exploiting multiple scattering of photons in an amplifying disordered medium in order to generate coherent light without a traditional laser resonator has attracted a great deal of attention in recent years. This research area lies at the interface of the fundamental theory of disordered systems and laser science. The idea was originally proposed in the context of astrophysics in the 1960s by V.S. Letokhov, who studied scattering with “negative absorption” of the interstellar molecular clouds. Research on random lasers has since developed into a mature experimental and theoretical field. A simple design of such lasers would be promising for potential applications. However, in traditional random lasers the properties of the output radiation are typically characterized by complex features in the spatial, spectral and time domains, making them less attractive than standard laser systems in terms of practical applications. Recently, an interesting and novel type of one-dimensional random laser that operates in a conventional telecommunication fibre without any pre-designed resonator mirrors-random distributed feedback fibre laser-was demonstrated. The positive feedback required for laser generation in random fibre lasers is provided by the Rayleigh scattering from the inhomogeneities of the refractive index that are naturally present in silica glass. In the proposed laser concept, the randomly backscattered light is amplified through the Raman effect, providing distributed gain over distances up to 100 km. Although an effective reflection due to the Rayleigh scattering is extremely small (˜0.1%), the lasing threshold may be exceeded when a sufficiently large distributed Raman gain is provided. Such a random distributed feedback fibre laser has a number of interesting and attractive features. The fibre waveguide geometry provides transverse confinement, and effectively one-dimensional random distributed feedback leads to the generation

  4. Highly efficient Raman distributed feedback fibre lasers.

    PubMed

    Shi, Jindan; Alam, Shaif-ul; Ibsen, Morten

    2012-02-27

    We demonstrate highly efficient Raman distributed feedback (DFB) fibre lasers for the first time with up to 1.6 W of continuous wave (CW) output power. The DFB Bragg gratings are written directly into two types of commercially available passive germano-silica fibres. Two lasers of 30 cm length are pumped with up to 15 W of CW power at 1068 nm. The threshold power is ~2 W for a Raman-DFB (R-DFB) laser written in standard low-NA fibre, and only ~1 W for a laser written in a high-NA fibre, both of which oscillate in a narrow linewidth of <0.01 nm at ~1117 nm and ~1109 nm, respectively. The slope efficiencies are ~74% and ~93% with respect to absorbed pump power in the low-NA fibre and high-NA fibre respectively. Such high conversion efficiency suggests that very little energy is lost in the form of heat through inefficient energy transfer. Our results are supported by numerical simulations, and furthermore open up for the possibility of having narrow linewidth all-fibre laser sources in wavelength bands not traditionally covered by rare-earth doped silica fibres. Simulations also imply that this technology has the potential to produce even shorter R-DFB laser devices at the centimetre-level and with mW-level thresholds, if Bragg gratings formed in fibre materials with higher intrinsic Raman gain coefficient than silica are used. These materials include for example tellurite or chalcogenide glasses. Using glasses like these would also open up the possibility of having narrow linewidth fibre sources with DFB laser oscillating much further into the IR than what currently is possible with rare-earth doped silica glasses.

  5. Image analysis of insulation mineral fibres.

    PubMed

    Talbot, H; Lee, T; Jeulin, D; Hanton, D; Hobbs, L W

    2000-12-01

    We present two methods for measuring the diameter and length of man-made vitreous fibres based on the automated image analysis of scanning electron microscopy images. The fibres we want to measure are used in materials such as glass wool, which in turn are used for thermal and acoustic insulation. The measurement of the diameters and lengths of these fibres is used by the glass wool industry for quality control purposes. To obtain reliable quality estimators, the measurement of several hundred images is necessary. These measurements are usually obtained manually by operators. Manual measurements, although reliable when performed by skilled operators, are slow due to the need for the operators to rest often to retain their ability to spot faint fibres on noisy backgrounds. Moreover, the task of measuring thousands of fibres every day, even with the help of semi-automated image analysis systems, is dull and repetitive. The need for an automated procedure which could replace manual measurements is quite real. For each of the two methods that we propose to accomplish this task, we present the sample preparation, the microscope setting and the image analysis algorithms used for the segmentation of the fibres and for their measurement. We also show how a statistical analysis of the results can alleviate most measurement biases, and how we can estimate the true distribution of fibre lengths by diameter class by measuring only the lengths of the fibres visible in the field of view.

  6. Hydrogen peroxide release and hydroxyl radical formation in mixtures containing mineral fibres and human neutrophils.

    PubMed

    Leanderson, P; Tagesson, C

    1992-11-01

    The ability of different mineral fibres (rock wool, glass wool, ceramic fibres, chrysotile A, chrysotile B, amosite, crocidolite, antophyllite, erionite, and wollastonite) to stimulate hydrogen peroxide (H2O2) and hydroxyl radical (OH.) formation in mixtures containing human polymorphonuclear leucocytes (PMNLs) was investigated. In the presence of azide, all the fibres caused considerable H2O2 formation, and about twice as much H2O2 was found in mixtures with the natural fibres (asbestos, erionite, and wollastonite) than in mixtures with the manmade fibres (rock wool, glass wool, and ceramic fibres). In the presence of externally added iron, all the fibres were found to generate OH. and the natural fibres caused about three times more OH. formation than the manmade fibres. In the absence of external iron, there was less OH. formation; however, amosite, crocidolite, antophyllite, erionite, and wollastonite still generated considerable amounts of OH., also under circumstances in which only small amounts of OH. were produced in mixtures with the manmade fibres. These findings indicate that natural fibres generate more H2O2 and OH. than manmade fibres when incubated with PMNLs in the presence of external iron. They also suggest that the natural fibres, amosite, crocidolite, antophyllite, erionite, and wollastonite may act catalytically in the dissociation of H2O2 to OH. in the absence of external iron, whereas manmade fibres such as rock wool, glass wool, and ceramic fibres, do not seem to be able to generate OH. in the absence of external iron.

  7. Hydrogen peroxide release and hydroxyl radical formation in mixtures containing mineral fibres and human neutrophils.

    PubMed Central

    Leanderson, P; Tagesson, C

    1992-01-01

    The ability of different mineral fibres (rock wool, glass wool, ceramic fibres, chrysotile A, chrysotile B, amosite, crocidolite, antophyllite, erionite, and wollastonite) to stimulate hydrogen peroxide (H2O2) and hydroxyl radical (OH.) formation in mixtures containing human polymorphonuclear leucocytes (PMNLs) was investigated. In the presence of azide, all the fibres caused considerable H2O2 formation, and about twice as much H2O2 was found in mixtures with the natural fibres (asbestos, erionite, and wollastonite) than in mixtures with the manmade fibres (rock wool, glass wool, and ceramic fibres). In the presence of externally added iron, all the fibres were found to generate OH. and the natural fibres caused about three times more OH. formation than the manmade fibres. In the absence of external iron, there was less OH. formation; however, amosite, crocidolite, antophyllite, erionite, and wollastonite still generated considerable amounts of OH., also under circumstances in which only small amounts of OH. were produced in mixtures with the manmade fibres. These findings indicate that natural fibres generate more H2O2 and OH. than manmade fibres when incubated with PMNLs in the presence of external iron. They also suggest that the natural fibres, amosite, crocidolite, antophyllite, erionite, and wollastonite may act catalytically in the dissociation of H2O2 to OH. in the absence of external iron, whereas manmade fibres such as rock wool, glass wool, and ceramic fibres, do not seem to be able to generate OH. in the absence of external iron. Images PMID:1334424

  8. Potential SRF generation from a closed landfill in northern Italy.

    PubMed

    Passamani, Giorgia; Ragazzi, Marco; Torretta, Vincenzo

    2016-01-01

    The aim of this work is to assess the possibility of producing solid recovered fuel (SRF) and "combustible SRF" from a landfill located in the north of Italy, where the waste is placed in cylindrical wrapped bales. Since the use of landfills for the disposal of municipal solid waste has many technical limitations and is subject to strict regulations and given that landfill post-closure care is very expensive, an interesting solution is to recover the bales that are stored in the landfill. The contents of the bales can then be used for energy recovery after specific treatments. Currently the landfill is closed and the local municipal council together with an environmental agency are considering constructing a mechanical biological treatment (MBT) plant for SRF production. The municipal solid waste that is stored in the landfill, the bio-dried material produced by the hypothetically treated waste in a plant for bio-drying, and the SRF obtained after the post-extraction of inert materials, metals and glass from the bio-dried material were characterized according to the quality and classification criteria of regulations in Italy. The analysis highlighted the need to treat the excavated waste in a bio-drying plant and later to remove the inert waste, metals and glass. Thus in compliance with Italian law, the material has a high enough LHV to be considered as "combustible SRF", (i.e. an SRF with enhanced characteristics). Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Erbium-doped aluminophosphosilicate optical fibres

    SciTech Connect

    Likhachev, M E; Bubnov, M M; Zotov, K V; Medvedkov, O I; Lipatov, D S; Yashkov, M V; Gur'yanov, Aleksei N

    2010-09-10

    We have studied the active properties of erbium-doped aluminophosphosilicate (APS) core fibres in wide ranges of erbia, alumina and phosphorus pentoxide concentrations. The absorption and luminescence spectra of the P{sub 2}O{sub 5}- or Al{sub 2}O{sub 3}-enriched erbium-doped APS fibres are shown to be similar to those of the erbium-doped fibres singly doped with phosphorus pentoxide or alumina, respectively. The formation of AlPO{sub 4} in APS fibres leads not only to a reduction in the refractive index of the glass but also to a marked increase in Er{sub 2}O{sub 3} solubility in silica. (optical fibres)

  10. BIOREACTOR LANDFILL DESIGN

    EPA Science Inventory

    Modern landfill design entails many elements including foundations, liner systems, leachate collection systems, stormwater control systems, slope stability considerations, leachate management systems, gas extraction systems, and capping and closure. The use of bioreactor technolo...

  11. Landfill gas recovery

    SciTech Connect

    MacDonald, A.

    1991-08-01

    This facility describes a project that began four years ago as an effort to control odor, but has since grown into the Northeast's largest landfill gas-to-electricity power project. A series of wells and miles of pipe snaking beneath the ground channel gas to the power plant. When operating at capacity, the Northeast Landfill Power Project in Rhode Island can produce 12.3 megawatts of electricity for sale enough to power about 17,500 households. Landfill gas (LFG) is produced naturally as organic solid waste decomposes. Typically, LFG consists of methane (50 to 55 percent), carbon dioxide (45 to 50 percent),a nd small amounts of nitrogen, oxygen and various trace elements. Left uncontrolled, LFG will migrate out of a landfill and into the atmosphere, creating odor, safety and environmental problems.

  12. Utilization of landfill gas

    SciTech Connect

    Golden, T. )

    1990-01-01

    Landfill gas is produced by the anaerobic decay of organic matter present in municipal solid waste. Raw landfill gas is composed primarily of carbon dioxide (45 vol percent) and methane (55 vol percent) with part-per-million levels of numerous chemical impurities. The U.S. Department of Energy estimates that over 200 billion cubic feet of methane are generated in landfills every year. To address this potential energy source the author's company has developed a landfill gas treatment system (LFGTS) as an economic means of producing high BTU gas. The LFGTS, presented in this paper, consists of three major processing steps: raw gas collection and compression, trace impurity removal and destruction by temperature swing adsorption, and carbon dioxide removal by pressure swing adsorption to produce pipeline quality methane.

  13. Bondad Landfill NPDES Permit

    EPA Pesticide Factsheets

    Under National Pollutant Discharge Elimination System permit number CO-R050005, Transit Waste, LLC is authorized to discharge from the Bondad Landfill facility in La Plata County, Colorado, to an unnamed tributary of the Animas River.

  14. BIOREACTOR LANDFILL DESIGN

    EPA Science Inventory

    Modern landfill design entails many elements including foundations, liner systems, leachate collection systems, stormwater control systems, slope stability considerations, leachate management systems, gas extraction systems, and capping and closure. The use of bioreactor technolo...

  15. Lancaster Landfill Solar Facility

    SciTech Connect

    Pacheco, Orlando

    2014-06-12

    The Town of Lancaster constructed a 500KWH Solar Array on our landfill parcel, that using other financial mechanisms in the deregulated Massachusetts Electric Market would allow the Town to obtain free electricity.

  16. A validation of the fibre orientation and fibre length attrition prediction for long fibre-reinforced thermoplastics

    SciTech Connect

    Hopmann, Ch.; Weber, M.; Haag, J. van; Schöngart, M.

    2015-05-22

    To improve the mechanical performance of polymeric parts, fibre reinforcement has established in industrial applications during the last decades. Next to the widely used Short Fibre-reinforced Thermoplastics (SFT) the use of Long Fibre-reinforced Thermoplastics (LFT) is increasingly growing. Especially for non-polar polymeric matrices like polypropylene (PP), longer fibres can significantly improve the mechanical performance. As with every kind of discontinuous fibre reinforcement the fibre orientations (FO) show a high impact on the mechanical properties. On the contrary to SFT where the local fibre length distribution (FLD) can be often neglected, for LFT the FLD show a high impact on the material’s properties and has to be taken into account in equal measure to the FOD. Recently numerical models are available in commercial filling simulation software and allow predicting both the local FOD and FLD in LFT parts. The aim of this paper is to compare i.) the FOD results and ii) the FLD results from available orientation- and fibre length attrition-models to those obtained from experimental data. The investigations are conducted by the use of different injection moulded specimens made from long glass fibre reinforced PP. In order to determine the FOD, selected part sections are examined by means of Computed Tomographic (CT) analyses. The fully three dimensional measurement of the FOD is then performed by digital image processing using grey scale correlation. The FLD results are also obtained by using digital image processing after a thermal pyrolytic separation of the polymeric matrix from the fibres. Further the FOD and the FLD are predicted by using a reduced strain closure (RSC) as well as an anisotropic rotary diffusion - reduced strain closure model (ARD-RSC) and Phelps-Tucker fibre length attrition model implemented in the commercial filling software Moldflow, Autodesk Inc., San Rafael, CA, USA.

  17. A validation of the fibre orientation and fibre length attrition prediction for long fibre-reinforced thermoplastics

    NASA Astrophysics Data System (ADS)

    Hopmann, Ch.; Weber, M.; van Haag, J.; Schöngart, M.

    2015-05-01

    To improve the mechanical performance of polymeric parts, fibre reinforcement has established in industrial applications during the last decades. Next to the widely used Short Fibre-reinforced Thermoplastics (SFT) the use of Long Fibre-reinforced Thermoplastics (LFT) is increasingly growing. Especially for non-polar polymeric matrices like polypropylene (PP), longer fibres can significantly improve the mechanical performance. As with every kind of discontinuous fibre reinforcement the fibre orientations (FO) show a high impact on the mechanical properties. On the contrary to SFT where the local fibre length distribution (FLD) can be often neglected, for LFT the FLD show a high impact on the material's properties and has to be taken into account in equal measure to the FOD. Recently numerical models are available in commercial filling simulation software and allow predicting both the local FOD and FLD in LFT parts. The aim of this paper is to compare i.) the FOD results and ii) the FLD results from available orientation- and fibre length attrition-models to those obtained from experimental data. The investigations are conducted by the use of different injection moulded specimens made from long glass fibre reinforced PP. In order to determine the FOD, selected part sections are examined by means of Computed Tomographic (CT) analyses. The fully three dimensional measurement of the FOD is then performed by digital image processing using grey scale correlation. The FLD results are also obtained by using digital image processing after a thermal pyrolytic separation of the polymeric matrix from the fibres. Further the FOD and the FLD are predicted by using a reduced strain closure (RSC) as well as an anisotropic rotary diffusion - reduced strain closure model (ARD-RSC) and Phelps-Tucker fibre length attrition model implemented in the commercial filling software Moldflow, Autodesk Inc., San Rafael, CA, USA.

  18. Strength and toughness of structural fibres for composite material reinforcement.

    PubMed

    Herráez, M; Fernández, A; Lopes, C S; González, C

    2016-07-13

    The characterization of the strength and fracture toughness of three common structural fibres, E-glass, AS4 carbon and Kevlar KM2, is presented in this work. The notched specimens were prepared by means of selective carving of individual fibres by means of the focused ion beam. A straight-fronted edge notch was introduced in a plane perpendicular to the fibre axis, with the relative notch depth being a0/D≈0.1 and the notch radius at the tip approximately 50 nm. The selection of the appropriate beam current during milling operations was performed to avoid to as much as possible any microstructural changes owing to ion impingement. Both notched and un-notched fibres were submitted to uniaxial tensile tests up to failure. The strength of the un-notched fibres was characterized in terms of the Weibull statistics, whereas the residual strength of the notched fibres was used to determine their apparent toughness. To this end, the stress intensity factor of a fronted edge crack was computed by means of the finite-element method for different crack lengths. The experimental results agreed with those reported in the literature for polyacrylonitrile-based carbon fibres obtained by using similar techniques. After mechanical testing, the fracture surface of the fibres was analysed to ascertain the failure mechanisms. It was found that AS4 carbon and E-glass fibres presented the lower toughness with fracture surfaces perpendicular to the fibre axis, emanating from the notch tip. The fractured region of Kevlar KM2 fibres extended along the fibre and showed large permanent deformation, which explains their higher degree of toughness when compared with carbon and glass fibres. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'.

  19. Strength and toughness of structural fibres for composite material reinforcement

    PubMed Central

    Herráez, M.; Fernández, A.; Lopes, C. S.

    2016-01-01

    The characterization of the strength and fracture toughness of three common structural fibres, E-glass, AS4 carbon and Kevlar KM2, is presented in this work. The notched specimens were prepared by means of selective carving of individual fibres by means of the focused ion beam. A straight-fronted edge notch was introduced in a plane perpendicular to the fibre axis, with the relative notch depth being a0/D≈0.1 and the notch radius at the tip approximately 50 nm. The selection of the appropriate beam current during milling operations was performed to avoid to as much as possible any microstructural changes owing to ion impingement. Both notched and un-notched fibres were submitted to uniaxial tensile tests up to failure. The strength of the un-notched fibres was characterized in terms of the Weibull statistics, whereas the residual strength of the notched fibres was used to determine their apparent toughness. To this end, the stress intensity factor of a fronted edge crack was computed by means of the finite-element method for different crack lengths. The experimental results agreed with those reported in the literature for polyacrylonitrile-based carbon fibres obtained by using similar techniques. After mechanical testing, the fracture surface of the fibres was analysed to ascertain the failure mechanisms. It was found that AS4 carbon and E-glass fibres presented the lower toughness with fracture surfaces perpendicular to the fibre axis, emanating from the notch tip. The fractured region of Kevlar KM2 fibres extended along the fibre and showed large permanent deformation, which explains their higher degree of toughness when compared with carbon and glass fibres. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’. PMID:27242306

  20. Self-assembled fibre optoelectronics with discrete translational symmetry

    NASA Astrophysics Data System (ADS)

    Rein, Michael; Levy, Etgar; Gumennik, Alexander; Abouraddy, Ayman F.; Joannopoulos, John; Fink, Yoel

    2016-10-01

    Fibres with electronic and photonic properties are essential building blocks for functional fabrics with system level attributes. The scalability of thermal fibre drawing approach offers access to large device quantities, while constraining the devices to be translational symmetric. Lifting this symmetry to create discrete devices in fibres will increase their utility. Here, we draw, from a macroscopic preform, fibres that have three parallel internal non-contacting continuous domains; a semiconducting glass between two conductors. We then heat the fibre and generate a capillary fluid instability, resulting in the selective transformation of the cylindrical semiconducting domain into discrete spheres while keeping the conductive domains unchanged. The cylindrical-to-spherical expansion bridges the continuous conducting domains to create ~104 self-assembled, electrically contacted and entirely packaged discrete spherical devices per metre of fibre. The photodetection and Mie resonance dependent response are measured by illuminating the fibre while connecting its ends to an electrical readout.

  1. Self-assembled fibre optoelectronics with discrete translational symmetry

    PubMed Central

    Rein, Michael; Levy, Etgar; Gumennik, Alexander; Abouraddy, Ayman F.; Joannopoulos, John; Fink, Yoel

    2016-01-01

    Fibres with electronic and photonic properties are essential building blocks for functional fabrics with system level attributes. The scalability of thermal fibre drawing approach offers access to large device quantities, while constraining the devices to be translational symmetric. Lifting this symmetry to create discrete devices in fibres will increase their utility. Here, we draw, from a macroscopic preform, fibres that have three parallel internal non-contacting continuous domains; a semiconducting glass between two conductors. We then heat the fibre and generate a capillary fluid instability, resulting in the selective transformation of the cylindrical semiconducting domain into discrete spheres while keeping the conductive domains unchanged. The cylindrical-to-spherical expansion bridges the continuous conducting domains to create ∼104 self-assembled, electrically contacted and entirely packaged discrete spherical devices per metre of fibre. The photodetection and Mie resonance dependent response are measured by illuminating the fibre while connecting its ends to an electrical readout. PMID:27698454

  2. Self-assembled fibre optoelectronics with discrete translational symmetry.

    PubMed

    Rein, Michael; Levy, Etgar; Gumennik, Alexander; Abouraddy, Ayman F; Joannopoulos, John; Fink, Yoel

    2016-10-04

    Fibres with electronic and photonic properties are essential building blocks for functional fabrics with system level attributes. The scalability of thermal fibre drawing approach offers access to large device quantities, while constraining the devices to be translational symmetric. Lifting this symmetry to create discrete devices in fibres will increase their utility. Here, we draw, from a macroscopic preform, fibres that have three parallel internal non-contacting continuous domains; a semiconducting glass between two conductors. We then heat the fibre and generate a capillary fluid instability, resulting in the selective transformation of the cylindrical semiconducting domain into discrete spheres while keeping the conductive domains unchanged. The cylindrical-to-spherical expansion bridges the continuous conducting domains to create ∼10(4) self-assembled, electrically contacted and entirely packaged discrete spherical devices per metre of fibre. The photodetection and Mie resonance dependent response are measured by illuminating the fibre while connecting its ends to an electrical readout.

  3. Numerical simulation of landfill gas pressure distribution in landfills.

    PubMed

    Xi, Yonghui; Xiong, Hao

    2013-11-01

    Landfill gas emissions are recognized as one of the three major concerns in municipal solid waste landfills. There are many factors that affect the generation of landfill gas when the landfill is capped. In this article, a model has been developed based on the theory of porous media flow. The model could predict the pressure distribution of landfill gas in landfill, coupling the effect of landfill settlement. According to the simulation analysis of landfill, it was found that: (a) the landfill gas pressure would reach a peak after 1.5 years, then begin to decline, and the rate of decay would slow down after 10 years; (b) the influence radius of the gas wells is limited; (c) the peak value of landfill gas pressure is larger, it appears later and the rate of decay is slower when the landfill settlement is considered in the model; (d) the calculation of excess gas pressure in landfill under different negative pressures of the extraction well is compared between this model and another model, and the results show that the relative pressure distribution form and range are almost the same.

  4. Municipal landfill leachate management

    SciTech Connect

    Kusterer, T.; Willson, R.; Bruce, S.C.; Tissue, E. Lou, P.J.

    1998-12-31

    From 1995 to 1997, the Montgomery County Leachate Pretreatment Facility (MCLPF) has successfully pretreated in excess of 18,000,000 gallons of leachate generated by the county`s municipal solid waste landfill. The collection system directs leachate from the original landfill. The collection system directs leachate from the original landfill, the new lined section, and the ash cell to the leachate pump station. The leachate, prior to being pumped to the leachate pretreatment system, is equalized in two storage lagoons with a combined capacity of more than 5,000,000 gallons. The innovative leachate treatment system, incorporating a biological reactor system equipped with a submerged fixed-film reactor using a patented Matrix Biological Film (MBF) media, continues to provide excellent pretreatment results for the leachate generated at the Oaks Landfill in Montgomery County, Maryland. In 1995 and 1996, the system responded to the substantial challenges imposed by the changing characteristics of the material being landfilled and by the significant amounts of incinerator ash, received in 1995 from the county`s resource recovery facility (RRF), which influenced the influent leachate characteristics.

  5. Migrating landfill gas proves challenging

    SciTech Connect

    Dobrowolski, J.G.; Dellinger, A.S.

    1994-12-01

    Located in the San Fernando Valley at the foothills of the San Gabriel mountains, the 41-acre Sheldon-Arleta Landfill originated as one of many gravel pits in the area and was operated by CalMat as a gravel quarry pit from the mid 1950s until 1962. In 1967, methane gas was detected in the residential dwellings located across from the landfill along Sharp Street. Three landfill gas wells were installed at the north corner of the landfill to control off-site migration of landfill gas. Landfill gas, through diffusion, saturates soil pores below and around the landfill. Groundwater serves as an effective barrier to landfill gas migration. Thus a rising water table mobilizes landfill gas from soil pores. Where that gas cannot be effectively collected, off-site migration will occur. The solution to ensuring public safety is to collect landfill gas on-site before it escapes the influence of gas collection wells. This may require complete reevaluation of an existing landfill gas collection system and potential renovation to collect greater quantities of land-fill gas. Cost-effective implementation of this strategy calls for two gas collection systems: one for collection of methane-rich landfill gas for electrical generation and resource recovery, and the other to control off-site migration of landfill gas through on-site combustion. Installation/upgrades of the foregoing solutions are long-term options. For the short-term immediate mitigation of high landfill gas migration, installation of a passive vent system was necessary with the option of active extraction. However, one must recognize that the public is ultimately better served by controlling landfill gas on-site before it approaches dangerous off-site levels.

  6. Management of old landfills by utilizing forest and energy industry waste flows.

    PubMed

    Niutanen, Ville; Korhonen, Jouni

    2002-05-01

    The lack of landfill capacity, forthcoming EU waste disposal and landfill management legislation and the use of non-renewable and energy intensive natural resources for the end-treatment of old landfills increase pressures to develop new landfill management methods. This paper considers a method for the end-management of old landfills in Finland, which is based on the utilization of forest and paper industry waste flows, wastes from paper recycling (de-inking) and wastes from forest industry energy production. Fibre clay wastes from paper mills, de-inking sludges from de-inking of recovered waste paper and incineration ash from forest industry power plants serve to substitute the use of natural clay for the building of landfill structures for closed landfills. Arguably, this method is preferable to existing practices of natural clay use for landfill building, because it (1) substitutes non-renewable natural clay, (2) consumes less energy and generates less CO2 emissions than the use of natural clay, and (3) eliminates considerable amounts of wastes from paper production, paper consumption and from forest industry energy production. Some difficulties in the application of the method are considered and the waste flow utilization is incorporated into a local forest industry recycling network.

  7. Method for treating landfill leachate

    SciTech Connect

    Singhvi, S.S.

    1993-08-24

    A method is described for removing contaminants from leachate of a landfill which produces landfill gas, comprising the steps of: (a) combusting the landfill gas to produce combustion products; (b) heating the leachate with said combustion products; (c) removing contaminants from the leachate by gas stripping; and (d) reducing the pH of the leachate with said combustion products.

  8. Baghdad Municipal Solid Waste Landfill

    DTIC Science & Technology

    2006-10-19

    SOLID WASTE LANDFILL SIGIR PA... Solid Waste Landfill 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT...Municipal Solid Waste Landfill , Baghdad, Iraq (Report Number SIGIR-PA-06-067) We are providing this project assessment report for your information

  9. The hygroscopic behavior of plant fibres: a review

    NASA Astrophysics Data System (ADS)

    Célino, Amandine; Freour, Sylvain; Jacquemin, Frederic; Casari, Pascal

    2013-12-01

    Environmental concern has resulted in a renewed interest in bio-based materials. Among them, plant fibres are perceived as an environmentally friendly substitute to glass fibres for the reinforcement of composites, particularly in automotive engineering. Due to their wide availability, low cost, low density, high-specific mechanical properties and eco-friendly image, they are increasingly being employed as reinforcements in polymer matrix composites. Indeed, their complex microstructure as a composite material makes plant fibre a really interesting and challenging subject to study. Research subjects about such fibres are abundant because there are always some issues to prevent their use at large scale (poor adhesion, variability, low thermal resistance, hydrophilic behavior). The choice of natural fibres rather than glass fibres as filler yields a change of the final properties of the composite. One of the most relevant differences between the two kinds of fibre is their response to humidity. Actually, glass fibres are considered as hydrophobic whereas plant fibres have a pronounced hydrophilic behavior. Composite materials are often submitted to variable climatic conditions during their lifetime, including unsteady hygroscopic conditions. However, in humid conditions, strong hydrophilic behaviour of such reinforcing fibres leads to high level of moisture absorption in wet environments. This results in the structural modification of the fibres and an evolution of their mechanical properties together with the composites in which they are fitted in. Thereby, the understanding of these moisture absorption mechanisms as well as the influence of water on the final properties of these fibres and their composites is of great interest to get a better control of such new biomaterials. This is the topic of this review paper.

  10. Fibre-reinforced materials.

    PubMed

    Brown, D

    2000-11-01

    This paper considers the role of fibres in the reinforcement of composite materials, and the significance of the form the fibre takes and the material from which it is made. The current dental applications of fibre reinforcement, including dental cements and splints, fibres made into structures for use in composites, denture bases and the contemporary use of fibres in fixed partial dentures, are reviewed. Their role in biomedical implants is surveyed and their future forecast.

  11. Airborne fibre levels associated with the use of MMMF brazing mats during welding operations.

    PubMed

    Waterman, L S; Purnell, C J; Anderson, P W

    1990-02-01

    In 1985 the Health and Safety Executive set a gravimetric Control Limit for airborne Man-Made Mineral Fibre and in 1987 a respirable fibre number Recommended Limit for Superfine MMMF. A limited investigation was carried out of the use of glass and ceramic fibre products used as protection against welding 'batter' and oxyacetylene welding flame. Airborne fibre levels are compared with the Occupational Exposure Limits.

  12. Bi-doped fibre lasers operating in the range 1470-1550 nm

    SciTech Connect

    Dianov, Evgenii M; Firstov, S V; Medvedkov, O I; Bufetov, Igor' A; Khopin, V F; Gur'yanov, Aleksei N

    2009-04-30

    Lasing in bismuth-doped optical fibres in the range 1470-1550 nm has been demonstrated for the first time. The gain media were Bi-doped phosphogermanosilicate and, for the first time, germanosilicate glass fibres. The gain spectrum of the phosphogermanosilicate fibres extends from 1300 to 1550 nm, the range which can be used in next-generation optical fibre communication systems. (letters)

  13. Surface Treated Natural Fibres as Filler in Biocomposites

    NASA Astrophysics Data System (ADS)

    Schwarzova, I.; Stevulova, N.; Singovszka, E.; Terpakova, E.

    2015-11-01

    Biocomposites based on natural fibres as organic filler have been studied for several years because traditional building materials such as concrete are increasingly being replaced by advanced composite materials. Natural fibres are a potential replacement of glass fibres in composite materials. Inherent advantages such as low density, biodegradability and comparable specific mechanical properties make natural fibres an attractive option. However, limitations such as poor thermal stability, moisture absorption and poor compatibility with matrix are challenges that need to be resolved. The primary objective of this research was to study the effect of surface treatment on properties of hemp hurds like a natural lignocellulosic material and composites made thereof. Industrial hemp fibre is the one of the most suitable fibres for use in composite materials because of its good specific properties, as well as it being biologically degradable and CO2 neutral. Improving interfacial bonding between fibres and matrix is an important factor in using hemp fibres as reinforcement in composites. In order to improve interfacial bonding, modifications can be made to the hemp fibres to remove non- cellulosic compounds, separate hemp fibres from their bundles, and modify the fibre surface. This paper contains the comparison of FTIR spectra caused by combination of physical and chemical treatment of hemp material with unmodified sample. Modification of hemp hurds was carried out by NaOH solution and by ultrasonic treatment (deionized water and NaOH solution were used as the cleaning mediums).

  14. Design of erbium doped double clad ZBLAN Fibre laser

    NASA Astrophysics Data System (ADS)

    Oladeji, A.; Phillips, A.; Lamrini, S.; Scholle, K.; Fuhrberg, P.; Seddon, A. B.; Benson, T. M.; Sujecki, S.

    2015-06-01

    A high powered octagonal double clad ZBLAN (33 μm/330 μm, NA=0.13) glass fibre for mid-infrared light generation is studied using a one dimensional rate equation model. The fibre laser design employs the concept of cascade lasing and includes up-conversion phenomena. The results obtained demonstrate that efficient cascade lasing may be achieved in practice without the need for fibre grating fabrication, as a sufficient level of feedback for laser action is provided by Fresnel light reflection at ZBLAN glass fibre air interfaces. Further enhancement of the laser efficiency can be achieved by terminating one of the fibre ends with a mirror. Simulation results show that the laser operation with 20 W of pump power at 0.98 μm wavelength can be achieved at 2.75 μm operating wavelength with Er3+ ion concentrations of 60,000 ppm.

  15. Energy potential of modern landfills

    SciTech Connect

    Bogner, J.E.

    1990-01-01

    Methane produced by refuse decomposition in a sanitary landfill can be recovered for commercial use. Landfill methane is currently under-utilized, with commercial recovery at only a small percentage of US landfills. New federal regulations mandating control of landfill gas migration and atmospheric emissions are providing impetus to methane recovery schemes as a means of recovering costs for increased environmental control. The benefits of landfill methane recovery include utilization of an inexpensive renewable energy resource, removal of explosive gas mixtures from the subsurface, and mitigation of observed historic increases in atmospheric methane. Increased commercial interest in landfill methane recovery is dependent on the final form of Clean Air Act amendments pertaining to gaseous emissions from landfills; market shifts in natural gas prices; financial incentives for development of renewable energy resources; and support for applied research and development to develop techniques for increased control of the gas generation process in situ. This paper will discuss the controls on methane generation in landfills. In addition, it will address how landfill regulations affect landfill design and site management practices which, in turn, influence decomposition rates. Finally, future trends in landfilling, and their relationship to gas production, will be examined. 19 refs., 2 figs., 3 tabs.

  16. Modelling gas generation for landfill.

    PubMed

    Chakma, Sumedha; Mathur, Shashi

    2016-09-27

    A methodology was developed to predict the optimum long-term spatial and temporal generation of landfill gases such as methane, carbon dioxide, ammonia, and hydrogen sulphide on post-closure landfill. The model incorporated the chemical and the biochemical processes responsible for the degradation of the municipal solid waste. The developed model also takes into account the effects of heterogeneity with different layers as observed at the site of landfills' morphology. The important parameters for gas generation due to biodegradation such as temperature, pH, and moisture content were incorporated. The maximum and the minimum generations of methane and hydrogen sulphide were observed. The rate of gas generation was found almost same throughout the depth after 30 years of landfill closure. The proposed model would be very useful for landfill engineering in the mining landfill gas and proper design for landfill gas management systems.

  17. Understanding and Improving the Elastic Compressive Modulus of Fibre Reinforced Soy-Based Polyurethane Foams

    NASA Astrophysics Data System (ADS)

    Hussain, Sadakat

    Soy-based polyurethane foams (PUFs) were reinforced with fibres of different aspect ratios to improve the compressive modulus. Each of the three fibre types reinforced PUF differently. Shorter micro-crystalline cellulose fibres were found embedded inside the cell struts of PUF and reinforced them. The reinforcement was attributed to be stress transfer from the matrix to the fibre by comparing the experimental results to those predicted by micro-mechanical models for short fibre reinforced composites. The reinforced cell struts increased the overall compressive modulus of the foam. Longer glass fibres (470 microns, length) provided the best reinforcement. These fibres were found to be larger than the cell diameters. The micro-mechanical models could not predict the reinforcement provided by the longer glass fibres. The models predicted negligible reinforcement because the very low modulus PUF should not transfer load to the higher modulus fibres. However, using a finite element model, it was determined that the fibres were providing reinforcement through direct fibre interaction with each other. Intermediate length glass fibres (260 microns, length) were found to poorly reinforce the PUF and should be avoided. These fibres were too short to interact with each other and were on average too large to embed and reinforce cell struts. In order to produce natural fibre reinforced PUFs in the future, a novel device was invented. The purpose of the device is to deliver natural fibres at a constant mass flow rate. The device was found to consistently meter individual loose natural fibre tufts at a mass flow rate of 2 grams per second. However, the device is not robust and requires further development to deliver a fine stream of natural fibre that can mix and interact with the curing polymeric components of PUF. A design plan was proposed to address the remaining issues with the device.

  18. ENGINEERING BULLETIN: LANDFILL COVERS

    EPA Science Inventory

    Landfill covers are used at Superfund sites to minimize surface water infiltration and control gas migration. In many cases covers are used in conjunction with other waste treatment technologies, such as slurry walls, ground water pump-and-treat systems, and gas collection. This ...

  19. ENGINEERING BULLETIN: LANDFILL COVERS

    EPA Science Inventory

    Landfill covers are used at Superfund sites to minimize surface water infiltration and control gas migration. In many cases covers are used in conjunction with other waste treatment technologies, such as slurry walls, ground water pump-and-treat systems, and gas collection. This ...

  20. Polychlorinated biphenyls in polysulfide sealants--occurrence and emission from a landfill station.

    PubMed

    Persson, N Johan; Pettersen, Harald; Ishaq, Rasha; Axelman, Johan; Bandh, Cecilia; Broman, Dag; Zebühr, Yngve; Hammar, Tommy

    2005-11-01

    Approximately 80,000 kg polysulfide sealant containing 10,000-18,000 kg polychlorinated biphenyls (PCB) was deposited at a Swedish municipal landfill station during 1965-1973. Investigations during 1994 showed that soil layers underneath the landfill had concentration of PCB not alarmingly high. The concentration of PCB congeners in ground water samples was elevated 4-750 times compared to a reference sample. Based on samples of ground water, leachate water, and flux chambers measuring evaporation of PCB from the landfill surface, the emission of PCB was estimated to be 1 g sigmaPCB/yr. This very low rate was attributed to the high sorptive capacity of the sealant. Compared to a reference site, the evaporation flux was elevated for the most volatile congeners, but factors 20-1400 lower than from another landfill which was contaminated with PCB in paper-pulp fibres.

  1. Modelling the extrusion of preforms for microstructured optical fibres

    NASA Astrophysics Data System (ADS)

    Tronnolone, Hayden; Stokes, Yvonne; Crowdy, Darren

    2013-11-01

    Owing to a novel design, microstructured optical fibres (MOFs) promise the realisation of fibres with effectively any desired optical properties. MOFs are typically constructed from glass and employ a series of air channels aligned along the fibre axis to form a waveguide. The construction of MOFs by first extruding a preform and then drawing this into the final fibre has the potential to produce fibres on an industrial scale; however, this is hindered by a limited understanding of the fluid flow that arises during this process. We focus on the extrusion stage of fabrication and discuss a model of the fibre evolution based upon complex-variable techniques. The relative influence of the various physical processes involved is discussed, along with limitations of the model.

  2. Amplifying properties of heavily erbium-doped active fibres

    SciTech Connect

    Plotskii, A Yu; Kurkov, Andrei S; Yashkov, M Yu; Bubnov, M M; Likhachev, M E; Sysolyatin, A A; Dianov, Evgenii M; Gur'yanov, A N

    2005-06-30

    The relative concentration of erbium ions undergoing nonradiative relaxation from the metastable to the ground level is measured in aluminosilicate glass fibres doped with erbium ions at concentration between 3x10{sup 18} and 10{sup 20} cm{sup -3}. The dependence of the fraction of such ions on the Er{sup 3+} concentration is determined for fibres containing different amounts of aluminium oxide in a core. It is shown that the fraction of erbium ions not involved in amplification substantially decreases with increasing the Al{sub 2}O{sub 3} concentration. It is found that clustering leads to a considerable decrease in the gain in heavily Er{sup 3+}-doped active fibres. The dependence of the quantum efficiency of a fibre amplifier on the erbium ion concentration is obtained based on the measurements performed. This dependence can be used for optimising the parameters of erbium-doped fibre amplifiers. (fibres. integrated-optic waveguides)

  3. Mathematical modelling of landfill gas migration in MSW sanitary landfills.

    PubMed

    Martín, S; Marañón, E; Sastre, H

    2001-10-01

    The laws that govern the displacement of landfill gas in a sanitary landfill are analysed. Subsequently, a 2-D finite difference flow model of a fluid in a steady state in a porous medium with infinite sources of landfill gas is proposed. The fact that landfill gas is continuously generated throughout the entire mass of the landfill differentiates this model from others extensively described in the literature and used in a variety of different applications, such as oil recovery, groundwater flow, etc. Preliminary results are then presented of the application of the model. Finally, the results obtained employing data from the literature and experimental assays carried out at the La Zoreda sanitary landfill (Asturias, Spain) are discussed and future lines of research are proposed.

  4. In-situ process and condition monitoring of advanced fibre-reinforced composite materials using optical fibre sensors

    NASA Astrophysics Data System (ADS)

    Doyle, C.; Martin, A.; Liu, T.; Wu, M.; Hayes, S.; Crosby, P. A.; Powell, G. R.; Brooks, D.; Fernando, G. F.

    1998-04-01

    This paper presents a general overview of a number of optical fibre sensor systems which have been developed and used in advanced fibre-reinforced composites for in-situ process and condition monitoring. The in-situ process monitoring techniques were optical-fibre-based evanescent wave spectroscopy, transmission near-infrared spectroscopy and refractive index monitoring. The optical fibre sensors were successful in tracking the cure reaction. The condition monitoring of advanced fibre-reinforced composites was carried out using two intensity-based optical fibre sensor systems: an extrinsic multi-mode Fabry-Pérot sensor and Bragg gratings. In addition to this, the feasibility of using the reinforcing fibre as a light guide was demonstrated. These sensor systems were evaluated under quasi-static, impact and fatigue loading. The test specimens consisted of prepreg-based carbon-fibre-reinforced epoxy and glass-fibre-reinforced epoxy filament-wound tubes. Excellent correlation was obtained between surface-mounted strain gauges and the embedded optical fibre sensors. The feasibility of using these sensor systems for the detection of impact damage and stiffness reduction in the composite due to fatigue damage was successfully demonstrated.

  5. Claymax landfill cap

    SciTech Connect

    Selby, C.L.

    1989-12-15

    A commercial product called Claymax'' consisting of one-quarter inch of bentonite clay between two geotextile sheets is a candidate landfill cap to replace kaolin caps. A permeability apparatus incorporating a 20 foot water head was operated for 56 days to estimate a Claymax permeability of 2 {times} 10{sup {minus}9} cm/sec compared with 10{sup {minus}8}, the EPA max for a burial site cap. 1 fig.

  6. Landfills in karst terrains

    SciTech Connect

    Hughes, T.H. ); Memon, B.A.; LaMoreaux, P.E. )

    1994-06-01

    State and Federal regulations have established restrictions for location of hazardous waste and municipal, solid waste landfills. Regulations require owners/operators to demonstrate that the hydrogeology has been completely characterized at proposed landfills, and that locations for monitoring wells have been properly selected. Owners/operators are also required to demonstrate that engineering measures have been incorporated in the design of the municipal solid waste landfills, so that the site is not subject to destabilizing events, as a result of location in unstable areas, such as karst terrains. Karst terrains are typically underlain by limestone or dolomite, and may contain a broad continuum of karst features and karst activity. Preliminary investigation of candidate sites will allow ranking of the sites, rejection of some unsuitable sites, and selection of a few sites for additional studies. The complexity of hydrogeologic systems, in karst terrains, mandates thorough hydrogeologic studies to determine whether a specific site is, or can be rendered, suitable for a land disposal facility. Important components of hydrogeologic studies are: field mapping of structural and stratigraphic units; interpretation of sequential aerial photographs; test drilling and geophysical analyses; fracture analyses; seasonal variation in water-levels; spatial variation of hydraulic characteristics of the aquifer and aquiclude; velocity and direction of movement of ground water within aquifers; determination of control for recharge, discharge, and local base level; and evaluation of the effects of man's activities, such as pumping, dewatering and construction.

  7. Phytoremediation of landfill leachate

    SciTech Connect

    Jones, D.L. . E-mail: d.jones@bangor.ac.uk; Williamson, K.L.; Owen, A.G.

    2006-07-01

    Leachate emissions from landfill sites are of concern, primarily due to their toxic impact when released unchecked into the environment, and the potential for landfill sites to generate leachate for many hundreds of years following closure. Consequently, economically and environmentally sustainable disposal options are a priority in waste management. One potential option is the use of soil-plant based remediation schemes. In many cases, using either trees (including short rotation coppice) or grassland, phytoremediation of leachate has been successful. However, there are a significant number of examples where phytoremediation has failed. Typically, this failure can be ascribed to excessive leachate application and poor management due to a fundamental lack of understanding of the plant-soil system. On balance, with careful management, phytoremediation can be viewed as a sustainable, cost effective and environmentally sound option which is capable of treating 250 m{sup 3} ha{sup -1} yr{sup -1}. However, these schemes have a requirement for large land areas and must be capable of responding to changes in leachate quality and quantity, problems of scheme establishment and maintenance, continual environmental monitoring and seasonal patterns of plant growth. Although the fundamental underpinning science is well understood, further work is required to create long-term predictive remediation models, full environmental impact assessments, a complete life-cycle analysis and economic analyses for a wide range of landfill scenarios.

  8. Fun with optical fibres

    NASA Astrophysics Data System (ADS)

    Alti, Kamlesh

    2017-07-01

    Optical fibres play a very crucial role in today’s technologies. Academic courses in optical fibres start at the undergraduate level. Nevertheless, student’s curiosity towards optical fibres starts from the school level. In this paper, some fun experiments have been designed for both school and college students, which have some concrete implications at the research level also.

  9. Fun with Optical Fibres

    ERIC Educational Resources Information Center

    Alti, Kamlesh

    2017-01-01

    Optical fibres play a very crucial role in today's technologies. Academic courses in optical fibres start at the undergraduate level. Nevertheless, student's curiosity towards optical fibres starts from the school level. In this paper, some fun experiments have been designed for both school and college students, which have some concrete…

  10. Passively cooled 405 W ytterbium fibre laser utilising a novel metal coated active fibre

    NASA Astrophysics Data System (ADS)

    Daniel, Jae M. O.; Simakov, Nikita; Hemming, Alexander; Clarkson, W. Andrew; Haub, John

    2016-03-01

    We present a novel metal coated triple clad active fibre design, utilising an all glass inner cladding structure and aluminium outer coating. This metal coated active fibre enables a number of benefits to high power laser design, such as increase robustness and extended operating temperature range. As a demonstration of the advantages of this design a passively cooled ytterbium fibre laser is presented. A 20 m length of active fibre was coiled into a planar arrangement and mounted onto a high emissivity heatsink. Up to 405 W of output power was achieved without the need for active water or forced air cooling. The slope efficiency of this source was 74 % and maximum outer heat sink temperature was ~140°C. This arrangement allowed for significant weight and size savings to be achieved with the active fibre laser head weighing less than 100 g. We will discuss the design choices and trade-offs of metal coated active fibre on high power fibre laser systems as well as the prospects for further power scaling to the kW level.

  11. Angiogenic effect induced by mineral fibres.

    PubMed

    Carbonari, Damiano; Campopiano, Antonella; Ramires, Deborah; Strafella, Elisabetta; Staffolani, Sara; Tomasetti, Marco; Curini, Roberta; Valentino, Matteo; Santarelli, Lory; Amati, Monica

    2011-10-09

    Due to the toxic effect of asbestos, other materials with similar chemical-physical characteristics have been introduced to substitute it. We evaluate the angiogenic effect of certain asbestos substitute fibres such as glass fibres (GFs), ceramic fibres (CFs) and wollastonite fibres (WFs) and then compare angiogenic responses to those induced by crocidolite asbestos fibres (AFs). An in vitro model using human endothelial cells in small islands within a culture matrix of fibroblasts (Angio-Kit) was used to evaluate vessel formation. The release of IL-6, sIL-R6, IL-8, VEGF-A and their soluble receptors, sVEGFR-1, sVEGFR-2, was determined in the conditioning medium of Angio-Kit system after fibre treatment. ROS formation and cell viability were evaluated in cultured endothelial cells (HUVEC). To evaluate the involvement of intracellular mechanisms, EGFR signalling, ROS formation and nuclear factor-κB (NFκB) pathway were then inhibited by incubating HUVEC cells with AG1478, NAC and PDTC respectively, and the cytokine and growth factor release was analyzed in the culture medium after 7 days of fibre incubation. Among the mineral fibres tested, WFs markedly induced blood vessel formation which was associated with release of IL-6 and IL-8, VEGF-A and their soluble receptors. ROS production was observed in HUVEC after WFs treatment which was associated with cell cytotoxicity. The EGFR-induced ERK phosphorylation and ROS-mediated NFκB activation were involved in the cytokine and angiogenic factor release. However, only the EGFR activation was able to induce angiogenesis. The WFs are potential angiogenic agents that can induce regenerative cytokine and angiogenic factor production resulting in the formation of new blood vessels.

  12. The effect of the addition of different fibres on the transverse and impact strength of acrylic resin denture base material.

    PubMed

    Rahamneh, A; Jagger, D C; Harrison, A

    2003-06-01

    The aim of the present study was to investigate the effect of the addition of different types of fibres on the transverse and impact strength of acrylic resin denture base material. The addition of glass fibres (strand) and polyethylene fibres produced a non significant increase in the modulus of elasticity, compared with the control of conventional heat-cured acrylic resin. The addition of glass fibres (woven and strand), polyethylene and carbon fibres to acrylic resin produced a non significant increase in the modulus of rupture. The addition of carbon, glass (strand) and polyethylene fibres produced a significant increase in the impact strength. Within the limitations of this study the addition of silk fibres did not produce an improvement in the mechanical properties.

  13. Biological durability and oxidative potential of man-made vitreous fibres as compared to crocidolite asbestos fibres.

    PubMed

    Hippeli, S; Dornisch, K; Wiethege, T; Gillissen, A; Müller, K M; Elstner, E F

    2001-01-01

    In this study we investigated relationships between redox properties and biodurability of crocidolite asbestos fibres and three different man-made vitreous fibres (MMVF): traditional stone wool fibres (MMVF 21), glass fibres (MMVF 11) and refractory ceramic fibres (RCF). Each fibre type was incubated up to 22 weeks in four different incubation media: gamble solution (GS) pH 5.0 and pH 7.4, representing blood plasma without proteins, and surfactant-like solution (SLS) pH 5.0 and pH 7.4. During incubation time aliquots of incubation mixtures were removed and analysed in a biochemical model reaction, mimicking activated phagocytes. In addition, changes of fibre morphology and chemical composition were examined using SEM- and EDX-technology. In the presence of crocidolite asbestos fibres and MMVF 21 the formation of OH*-radicals according to the Haber-Weiss sequence could be demonstrated, whereas MMVF 11 and RCF showed no reactivity. Crocidolite asbestos fibres exhibited a significant higher activity compared with the stone wool fibres at the onset of incubation. The oxidative capacities of these fibre types were shown to depend on both specific surface area and iron content. The oxidative potentials of crocidolite asbestos fibres as well as MMVF 21 were not constant during incubation over several weeks in each incubation medium. The reactivities showed sinoidal curves including reactivities much higher than those at the onset of incubation time. These irregular changes of oxidative capacity may be explained by changes of the redox state of fibre surface-complexed iron. Furthermore our results showed clear differences between incubation of fibres in GS and SLS, respectively, indicating that phospholipids play an important part in fibre dissolution behaviour and oxidative reactivity. In conclusion we suggest, that biodurability testing procedures should not exclusively concentrate on dissolution rates of fibres. They should include fibre characteristics concerning known

  14. Landfill Gas Energy Project Data and Landfill Technical Data

    EPA Pesticide Factsheets

    This page provides data from the LMOP Database for U.S. landfills and LFG energy projects in Excel files, a map of project and candidate landfill counts by state, project profiles for a select group of projects, and information about Project Expo sites.

  15. Fibre Optics In Automobiles

    NASA Astrophysics Data System (ADS)

    Harmer, A. L.

    1984-08-01

    Optical fibres are used in three application areas in automobiles. Illumination of the dashboard is done with a single lamp and monofilament fibres or woven tapes which illuminate the front panel. Fibre-optic multiplexing can replace the conventional wiring harness. Different trial systems (two-fibre links, bidirectional transmission, star-coupled architecture) are reviewed. Problems still exist in component performance, high costs and unknown reliability of optoelectronic systems. Fibre-optics are also used in sensors; for headlight monitoring, liquid-level sensing and other applications.

  16. Man-made mineral (vitreous) fibres: evaluations of cancer hazards by the IARC Monographs Programme.

    PubMed

    Baan, Robert A; Grosse, Yann

    2004-09-03

    Man-made vitreous (glass-like) fibres are non-crystalline, fibrous inorganic substances (silicates) made primarily from rock, slag, glass or other processed minerals. These materials, also called man-made mineral fibres, include glass fibres (used in glass wool and continuous glass filament), rock or stone wool, slag wool and refractory ceramic fibres. They are widely used for thermal and acoustical insulation and to a lesser extent for other purposes. These products are potentially hazardous to human health because they release airborne respirable fibres during their production, use and removal. Man-made mineral fibres and man-made vitreous fibres have been the subject of reviews by IARC Monographs Working Groups in 1987 and 2001, respectively, which resulted in evaluations of the carcinogenic hazard to humans from exposure to these materials. These reviews and evaluations have been published as Volumes 43 and 81 of the IARC Monographs series [IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, vol. 43, Man-made Mineral Fibres and Radon (1988); IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, vol. 81, Man-made Vitreous Fibres (2002)]. The re-evaluation in 2001 was undertaken because there have been substantial improvements in the quality of the epidemiological information available on the carcinogenicity to humans of glass fibres, continuous glass filament and rock/slag wool. The new evaluations have addressed the limitations of earlier cohort studies, particularly concerning the lack of adjustment with respect to concomitant risk factors such as smoking and other sources of occupational exposure. In addition, the evaluation of the evidence for carcinogenicity of glass fibres to experimental animals has been refined, by making a distinction between insulation glass wool and special-purpose glass fibres. The results of the evaluations in 1987 and 2001 are thus different in several aspects. In this paper, the reviews and evaluations

  17. Landfill gas management in Canada

    SciTech Connect

    David, A.

    1997-12-31

    Landfill gas produced from solid waste landfills is one of the most significant sources of anthropogenic methane in Canada. Methane, a potent greenhouse gas, is 24.5 times more powerful than carbon dioxide by weight in terms of global climate change. Landfill gas recovery plays an important role in Canada`s commitment to stabilize greenhouse gas emissions at 1990 levels by the year 2000 under the United Nations Framework Convention on Climate Change. Landfill gas is a potentially harmful emission that can be converted into a reliable environmentally-sustainable energy source used to generate electricity, fuel industries and heat buildings. The recovery and utilization of landfill gas is a win-win situation which makes good sense from local, regional and global perspectives. It provides the benefits of (1) reducing the release of greenhouse gases that contribute to global warming; (2) limiting odors; (3) controlling damage to vegetation; (4) reducing risks from explosions, fires and asphyxiation; (5) converting a harmful emission into a reliable energy source; and (6) creating a potential source of revenue and profit. Canadian landfills generate about 1 million tons of methane every year; the equivalent energy of 9 million barrels of oil (eight oil super tankers), or enough energy to meet the annual heating needs of more than half a million Canadian homes. Currently, twenty-seven facilities recover and combust roughly 25% of the methane generated by Canadian landfills producing about 3.2 PJ (10{sup 15} Joules) of energy including 80 MW of electricity and direct fuel for nearby facilities (e.g., cement plants, gypsum board manufacturers, recycling facilities, greenhouses). This paper reviews landfill gas characteristics; environmental, health and safety impacts; landfill gas management in Canada; the costs of landfill gas recovery and utilization systems; and on-going projects on landfill gas utilization and flaring.

  18. Landfill gas production from large landfill simulators. Final report

    SciTech Connect

    Jones, L.W.; Larson, R.J.; Malone, P.G.

    1984-08-01

    Two sizes of landfill simulators or test cells; one set containing approximately 320 kg wet weight of municipal solid wastes (MSW) and the other set containing 2555 kg wet weight of MSW were used to measure the amount and composition of gases produced from MSW under typical landfill conditions. The relative amounts and gas compositions follow those reported by other investigators. This study demonstrates that the conditions present in the average MSW landfill are not ideal for maximum production of methane; but large quantities of methane can, nevertheless, be produced over the active decomposition period of landfilled MSW. Further studies on the effects of environmental and microbial nutritional factors on methane production in landfilled MSW are recommended.

  19. Use of steel fibres recovered from waste tyres as reinforcement in concrete: pull-out behaviour, compressive and flexural strength.

    PubMed

    Aiello, M A; Leuzzi, F; Centonze, G; Maffezzoli, A

    2009-06-01

    The increasing amount of waste tyres worldwide makes the disposition of tyres a relevant problem to be solved. In the last years over three million tons of waste tyres were generated in the EU states [ETRA, 2006. Tyre Technology International - Trends in Tyre Recycling. http://www.etra-eu.org]; most of them were disposed into landfills. Since the European Union Landfill Directive (EU Landfill, 1999) aims to significantly reduce the landfill disposal of waste tyres, the development of new markets for the tyres becomes fundamental. Recently some research has been devoted to the use of granulated rubber and steel fibres recovered from waste tyres in concrete. In particular, the concrete obtained by adding recycled steel fibres evidenced a satisfactory improvement of the fragile matrix, mostly in terms of toughness and post-cracking behaviour. As a consequence RSFRC (recycled steel fibres reinforced concrete) appears a promising candidate for both structural and non-structural applications. Within this context a research project was undertaken at the University of Salento (Italy) aiming to investigate the mechanical behaviour of concrete reinforced with RSF (recycled steel fibres) recovered from waste tyres by a mechanical process. In the present paper results obtained by the experimental work performed up to now are reported. In order to evaluate the concrete-fibres bond characteristics and to determine the critical fibre length, pull-out tests were initially carried out. Furthermore compressive strength of concrete was evaluated for different volume ratios of added RSF and flexural tests were performed to analyze the post-cracking behaviour of RSFRC. For comparison purposes, samples reinforced with industrial steel fibres (ISF) were also considered. Satisfactory results were obtained regarding the bond between recycled steel fibres and concrete; on the other hand compressive strength of concrete seems unaffected by the presence of fibres despite their irregular

  20. Waveguiding properties and the spectrum of modes of hollow-core photonic-crystal fibres

    SciTech Connect

    Fedotov, Andrei B; Konorov, Stanislav O; Kolevatova, O A; Zheltikov, Aleksei M; Beloglazov, V I; Skibina, N B; Shcherbakov, Andrei V; Mel'nikov, L A

    2003-03-31

    Glass fibres with a hollow core and a two-dimensionally periodic cladding are studied experimentally and theoretically. The spectrum of modes guided in the hollow core of these fibres displays isolated maxima, indicating that waveguiding is supported due to the high reflectivity of the fibre cladding within photonic band gaps. The main properties of the spectrum of modes guided in a hollow core of a photonic-crystal fibre and radiation intensity distribution in these modes are qualitatively explained in terms of the model of a periodic coaxial waveguide. (fibre optics)

  1. Stabilizing Waste Materials for Landfills

    ERIC Educational Resources Information Center

    Environmental Science and Technology, 1977

    1977-01-01

    The test procedures used to evaluate the suitability of landfilled materials of varying stability and to determine the leachate from such materials are reviewed. A process for stabilizing a mixture of sulfur dioxide sludge, fly ash, and bottom ash with lime and other additives for deposition in landfills is detailed. (BT)

  2. Leachate evaporation using landfill gas

    SciTech Connect

    White, T.M.; Grace, V.M.; Freivald, W.

    1996-05-01

    This paper describes a century-old technology with a new twist of using landfill gas as a fuel in an evaporation system. The system is designed to help landfills reduce the cost of leachate disposal while also destroying VOC emissions in an enclosed flare.

  3. Changing face of the landfill

    SciTech Connect

    1995-10-01

    Integrated approach at Oregon landfill diverts wood and yard trimmings, while turning methane into power for 1,800 homes. Opened in the 1940`s as an open burn dump, Coffin Butte has evolved over the years into a sophisticated waste management facility incorporating ambitious recovery programs. While some of this change has been driven by regulatory demands, many of Valley Landfill`s innovations have come in response to market opportunities. Valley Landfill`s Processing and Recovery Center (PRC) is located a half mile down the road from the landfill site. Opened in 1990, the facility recycles urban wood waste, yard trimmings and street sweepings. The heart of this operation is a 500 hp horizontal feed, fixed-hammer grinder. Although this machine is typically used only for wood grinding, PRC was able to adapt it to handle both wood and yard trimmings by installing special feed roll assembly to compress green waste passing over the infeed belt. The facility handles approximately 40,000 cubic yards of loose green material and produces 15,000 to 18,000 yards of compost. The finished product is run through a trommel with a 5/8 inch mesh screen. Most of the compost is sold in bulk to area garden centers. A portion is processed through a 3/8 inch shaker screen and sold to a local company for use in bagged soil products. Valley Landfill is a partner in an ambitious project to generate electricity from landfill biogas.

  4. Stabilizing Waste Materials for Landfills

    ERIC Educational Resources Information Center

    Environmental Science and Technology, 1977

    1977-01-01

    The test procedures used to evaluate the suitability of landfilled materials of varying stability and to determine the leachate from such materials are reviewed. A process for stabilizing a mixture of sulfur dioxide sludge, fly ash, and bottom ash with lime and other additives for deposition in landfills is detailed. (BT)

  5. Photoinduced changes in the Raman spectra of germanosilicate optical fibres

    SciTech Connect

    Vasil'ev, Sergei A; Dianov, Evgenii M; Koltashev, V V; Mashinsky, V M; Medvedkov, O I; Plotnichenko, V G; Pyrkov, Yu N; Sazhin, O D; Frolov, A A; Marchenko, V M

    1998-04-30

    An investigation was made of changes in the Raman spectra of germanosilicate optical fibres as a result of UV irradiation. The photoinduced changes in the spectra were of the same nature for all types of irradiation used. These changes increased with increase in the radiation dose and in the GeO{sub 2} concentration in the fibre core and were evidence of a structural modification of glass. (nonlinear optical phenomena and devices)

  6. Landfill to Learning Facility

    NASA Astrophysics Data System (ADS)

    Venner, L.; Lewicki, S.

    2008-11-01

    Engaging ``K-to-Gray'' audiences (children, families, and older adults) in scientific exploration and discovery is the main goal of the New Jersey Meadowlands Commission (NJMC) Center for Environmental and Scientific Education (CESE) and the William D. McDowell Observatory located in Lyndhurst, NJ and operated by Ramapo College of New Jersey. Perched atop a closed and reclaimed municipal solid waste landfill, our new LEED--certified building (certification pending) and William D. McDowell observatory brings hands-on scientific experiences to the ˜25,000 students and ˜15,000 visitors that come to our site from the NY/NJ region each year.

  7. Application of Raman spectroscopy to forensic fibre cases.

    PubMed

    Lepot, L; De Wael, K; Gason, F; Gilbert, B

    2008-09-01

    Five forensic fibre cases in which Raman spectroscopy proved to be a good complementary method for microspectrophotometry (MSP) are described. Absorption spectra in the visible range are indeed sometimes characteristic ofa certain dye but this one can be subsequently identified unambiguously by Raman spectroscopy using a spectral library. In other cases the comparison of Raman spectra of reference fibres and suspect fibres led to an improvement of the discrimination power. The Raman measurements have been performed directly on mounted fibres and the spectra showed only little interference from the mounting resin and glass. Raman spectroscopy is therefore a powerful method that can be applied in routine fibre analysis following optical microscopy and MSP measurements.

  8. Gain-switched holmium-doped fibre laser.

    PubMed

    Wu, Ka S; Ottaway, David; Munch, Jesper; Lancaster, David G; Bennetts, Shayne; Jackson, Stuart D

    2009-11-09

    We demonstrate the first gain-switched, singly doped, single-mode holmium-doped silicate glass fibre laser that operates at 2.106 microm. Using a gain-switched 1.909-microm thulium-doped fibre laser as the pump source, output pulses of energy 3.2 microJ and pulse duration of 150 ns were generated at 80 kHz and slope efficiency of 44%. Pulse stacking within the holmium-doped fibre laser resulted in significantly shorter 70 ns pulses.

  9. Therapeutic role of dietary fibre.

    PubMed Central

    Hunt, R.; Fedorak, R.; Frohlich, J.; McLennan, C.; Pavilanis, A.

    1993-01-01

    The current status of dietary fibre and fibre supplements in health and disease is reported, and the components of dietary fibre and its respective mechanical and metabolic effects with emphasis on its therapeutic potential are reviewed. Practical management guidelines are provided to help physicians encourage patients identified as having fibre deficiency to increase dietary fibre intake to the recommended level. PMID:8388284

  10. Methane emissions from MBT landfills

    SciTech Connect

    Heyer, K.-U. Hupe, K.; Stegmann, R.

    2013-09-15

    Highlights: • Compilation of methane generation potential of mechanical biological treated (MBT) municipal solid waste. • Impacts and kinetics of landfill gas production of MBT landfills, approach with differentiated half-lives. • Methane oxidation in the waste itself and in soil covers. • Estimation of methane emissions from MBT landfills in Germany. - Abstract: Within the scope of an investigation for the German Federal Environment Agency (“Umweltbundesamt”), the basics for the estimation of the methane emissions from the landfilling of mechanically and biologically treated waste (MBT) were developed. For this purpose, topical research including monitoring results regarding the gas balance at MBT landfills was evaluated. For waste treated to the required German standards, a methane formation potential of approximately 18–24 m{sup 3} CH{sub 4}/t of total dry solids may be expected. Monitoring results from MBT landfills show that a three-phase model with differentiated half-lives describes the degradation kinetics in the best way. This is due to the fact that during the first years of disposal, the anaerobic degradation processes still proceed relatively intensively. In addition in the long term (decades), a residual gas production at a low level is still to be expected. Most of the soils used in recultivation layer systems at German landfills show a relatively high methane oxidation capacity up to 5 l CH{sub 4}/(m{sup 2} h). However, measurements at MBT disposal sites indicate that the majority of the landfill gas (in particular at non-covered areas), leaves the landfill body via preferred gas emission zones (hot spots) without significant methane oxidation. Therefore, rather low methane oxidation factors are recommended for open and temporarily covered MBT landfills. Higher methane oxidation rates can be achieved when the soil/recultivation layer is adequately designed and operated. Based on the elaborated default values, the First Order Decay (FOD

  11. Chalcogenide microstructured optical fibres for mid-IR applications

    NASA Astrophysics Data System (ADS)

    Trolès, Johann; Brilland, Laurent

    2017-01-01

    Compared to oxide-based glasses, vitreous materials composed of chalcogen elements (S, Se, Te) show large transparency windows in the infrared. Indeed, chalcogenide glasses can be transparent from the visible up to 12- 18 μm, depending on their compositions. In addition, chalcogenide glasses contain large polarisable atoms and external lone electron pairs that induce exceptional non-linear properties. Consequently, the non-linear properties can be 100 or 1000 times as high as the non-linearity of silica. An original way to obtain single-mode fibres is to design microstructured optical fibres (MOFs). These fibres present unique optical properties thanks to the high degree of freedom in the design of their geometrical structure. Various chalcogenide MOFs operating in the IR range have been elaborated in order to associate the high non-linear properties of these glasses with the original MOF properties. Indeed, chalcogenide MOFs might lead to new devices with unique optical properties in the mid-infrared domain, like multimode or endlessly single-mode transmission of light, small or large mode area fibres, highly birefringent fibres and non-linear properties for wavelength conversion or generation of supercontinuum sources. xml:lang="fr"

  12. Fibres For Sensors

    NASA Astrophysics Data System (ADS)

    Payne, D. N.

    1984-11-01

    Sensors which rely on the external modulation of the properties of an optical fibre (intrinsic sensors) are receiving much attention since they can be made extremely sensitive, and can be used for distributed measurements. Distributed sensing provides some particularly exciting prospects for acoustic, magnetic and electric field monitoring. To date, however, the great majority of experimental and commercial fibre sensors employ telecommunications-grade fibres, largely as a result of their ready availability. Not only does this policy frequently lead to a design compromise, but in some cases makes the performance marginal or untenable as a result of excessive environmental sensitivity. Despite this, little attention has been given to the design of special sensor fibres with enhanced (or depressed) sensitivity to specific measurands. The position is somewhat better with respect to fibres designed to eliminate sensor polarisation problems (e.g. polar isation-maintaining fibres), but even here further work is required to provide the performance demanded.

  13. Chronic inhalation studies of man-made vitreous fibres: characterization of fibres in the exposure aerosol and lungs.

    PubMed

    Hesterberg, T W; Miiller, W C; Thevenaz, P; Anderson, R

    1995-10-01

    Inhalation studies were conducted to determine the chronic biological effects in rodents of respirable fractions of different man-made vitreous fibres (MMVFs), including refractory ceramic fibre (RCF), fibrous glass, rock (stone) wool and slag wool. Animals were exposed nose-only, 6 h per day, 5 days per week, for 18 months (hamsters) or 24 months (rats). Exposure to 10 mg m-3 of crocidolite or chrysotile asbestos induced pulmonary fibrosis, lung tumours and mesothelioma in rats, thus validating the inhalation model with known human carcinogenic fibres. Exposure of rats to 30 mg m-3 of refractory ceramic fibres (RCF) also resulted in pulmonary fibrosis as well as significant increases in lung tumours and mesothelioma. In hamsters, 30 mg m-3 of RCF induced a 41% incidence of mesotheliomas. Exposure of rats to 30 mg m-3 of fibre glasses (MMVF 10 or 11) or of slag wool (MMVF 22) was associated with an inflammatory response, but no mesotheliomas or significant increase in the lung tumours were observed. Rock wool (stone wool: MMVF 21) at the same exposure level resulted in minimal lung fibrosis, but no mesotheliomas or significant increase in the lung tumours were observed. Fibre numbers (WHO fibres) and dimensions in the aerosols and lungs of exposed animals were comparable in this series of inhalation studies. Differences in lung fibre burdens and lung clearance rates could not explain the differences observed in the toxicologic effects of the MMVFs. These findings indicate that dose, dimension and durability may not be the only determinants of fibre toxicity. Chemical composition and the surface physico-chemical properties of the fibres may also play an important role.

  14. Sour landfill gas problem solved

    SciTech Connect

    Nagl, G.; Cantrall, R.

    1996-05-01

    In Broward County, Fla., near Pompano Beach, Waste Management of North America (WMNA, a subsidiary of WMX Technologies, Oak Brook, IL) operates the Central Sanitary Landfill and Recycling Center, which includes the country`s largest landfill gas-to-energy plant. The landfill consists of three collection sites: one site is closed, one is currently receiving garbage, and one will open in the future. Approximately 9 million standard cubic feet (scf) per day of landfill gas is collected from approximately 300 wells spread over the 250-acre landfill. With a dramatic increase of sulfur-containing waste coming to a South Florida landfill following Hurricane Andrew, odors related to hydrogen sulfide became a serious problem. However, in a matter of weeks, an innovative desulfurization unit helped calm the landfill operator`s fears. These very high H{sub 2}S concentrations caused severe odor problems in the surrounding residential area, corrosion problems in the compressors, and sulfur dioxide (SO{sub 2}) emission problems in the exhaust gas from the turbine generators.

  15. HIPPI and Fibre Channel

    SciTech Connect

    Tolmie, D.E.

    1992-01-01

    The High-Performance Parallel Interface (HIPPI) and Fibre Channel are near-gigabit per second data communications interfaces being developed in ANSI standards Task Group X3T9.3. HIPPI is the current interface of choice in the high-end and supercomputer arena, and Fibre Channel is a follow-on effort. HIPPI came from a local area network background, and Fibre Channel came from a mainframe to peripheral interface background.

  16. Effect of temperature on the active properties of erbium-doped optical fibres

    SciTech Connect

    Kotov, L V; Ignat'ev, A D; Bubnov, M M; Likhachev, M E

    2016-03-31

    We have studied the effect of heating on the performance of erbium-doped fibre based devices and determined temperaturedependent absorption and emission cross sections of the erbium ion in silica glass. The results demonstrate that heating of fibres in claddingpumped high-power (∼100 W) erbium-doped fibre lasers causes no significant decrease in their efficiency. In contrast, superluminescent sources operating in the long-wavelength region (1565 – 1610 nm) are extremely sensitive to temperature changes. (fiber optics)

  17. High efficiency Yb3+-doped phosphate single-mode fibre laser

    NASA Astrophysics Data System (ADS)

    Franczyk, M.; Stępień, R.; Piechal, B.; Pysz, D.; Stawicki, K.; Siwicki, B.; Buczyński, R.

    2017-10-01

    We report on a ytterbium-doped phosphate glass single-mode fibre laser, 4 cm long, with a maximum output power of 11.6 W and a slope efficiency of 66.6%. We developed the double-clad fibre with a 19 µm diameter step-index core and a pump waveguide with a high numerical aperture due to external air-cladding. The estimated pump absorption in the fibre exceeded 700 dB m‑1.

  18. Oxide glasses for mid-infrared lasers

    NASA Astrophysics Data System (ADS)

    Richards, Billy D. O.; Jha, Animesh; Jose, Gin; Jiang, Xin

    2011-06-01

    We present an overview of rare-earth doped heavy metal oxide and oxy-fluoride glasses which show promise as host materials for lasers operating in the 2-5 μm spectral region for medical, military and sensing applications. By engineering glass composition and purity, tellurite and germanate glasses can support transmission up to and beyond 5 μm and can have favourable thermal, mechanical and environmental stability compared to fluoride glasses. We discuss techniques for glass purification and water removal for enhanced infrared transmission. By comparing the material properties of the glass, and spectroscopic performance of selected rare-earth dopant ions we can identify promising compositions for fibre and bulk lasers in the mid-infrared. Tellurite glass has recently been demonstrated to be a suitable host material for efficient and compact lasers in the {2 μm spectral region in fibre and bulk form and the next challenge is to extend the operating range further into the infrared region where silica fibre is not sufficiently transparent, and provide an alternative to fluoride glass and fibre.

  19. Inhibition of cytokinesis by asbestos and synthetic fibres.

    PubMed

    Jensen, C G; Watson, M

    1999-01-01

    Using high-resolution timelapse microscopy, we have followed individual phagocytized fibres through the later stages of division in MeT-5A human mesothelial cells and LLC-MK(2)monkey epithelial cells. The fibres used were crocidolite and chrysotile asbestos, fibrous glass (MMVF), and refractory ceramic fibres (RCF). Long fibres (15-80 microm) trapped within the cleavage furrow can partially or completely block cytokinesis. Cells proceed in one of three ways: (1) eventual completion of cytokinesis; (2) incomplete cytokinesis, resulting in two cells joined by a fibre-containing intercellular channel; or (3) failure of cytokinesis, resulting in a binucleate or trinucleate cell. Two factors associated with fibre-induced bi/trinucleation are: (1) an initial association between the fibre and the forming daughter nuclei, which is sometimes lost over time, and (2) disintegration of the midbody. The studies suggest that delay of cytokinesis by interzonal fibres can result in bi/trinucleation through the loss of midbody/intercellular bridge proteins that are required for completion of cytokinesis.

  20. XPS identification of surface-initiated polymerisation during monomer transfer moulding of poly(ɛ-caprolactone)/Bioglass ® fibre composite

    NASA Astrophysics Data System (ADS)

    Jiang, G.; Walker, G. S.; Jones, I. A.; Rudd, C. D.

    2005-12-01

    In this work, X-ray photoelectron spectroscopy (XPS) was demonstrated to be a useful method to characterise surface-initiated polymerisation. Both E-glass fibre and Bioglass ® fibre were treated using 3-aminopropyltrimethoxysilane (and propyltrimethoxysilane as a control) and then they were used as a reinforcement, respectively, in monomer transfer moulding to prepare poly(ɛ-caprolactone)/glass fibre composites with stannous octoate as the catalyst for ɛ-caprolactone polymerisation. The fibre was extracted and then analysed using XPS to probe the presence of PCL chemically bonded to the glass fibre surface. Both tin and PCL were detected on the surface of the fibres sized with 3-aminopropyltrimethoxysilane, confirming surface-initiated polymerisation of ɛ-caprolactone.

  1. Astronomy on a Landfill

    NASA Astrophysics Data System (ADS)

    Venner, L.

    2008-11-01

    Engaging ``K-to-Gray'' audiences (children, families, and older adults) in astronomical activities is one of the main goals of the New Jersey Meadowlands Commission Center for Environmental and Scientific Education (CESE) and the William D. McDowell Observatory located in Lyndhurst, NJ, operated by Ramapo College of New Jersey. Perched atop a closed and reclaimed municipal solid waste landfill, our new LEED--certified building (certification pending) and William D. McDowell observatory will assist in bringing the goals of the International Year of Astronomy 2009 (IYA2009) to the ˜25,000 students and ˜15,000 visitors that visit our site from the NY/NJ region each year.

  2. Landfill Gas Energy Benefits Calculator

    EPA Pesticide Factsheets

    This page contains the LFG Energy Benefits Calculator to estimate direct, avoided, and total greenhouse gas reductions, as well as environmental and energy benefits, for a landfill gas energy project.

  3. Landfill gas project. Final report

    SciTech Connect

    1983-01-01

    The methane gas recovered from the landfill is used for space heating and water heating for the Florence-Lauderdale Humane Shelter 600 feet from the well head. The project to date and future development are described briefly. (MHR)

  4. Sanitary landfill groundwater monitoring report

    SciTech Connect

    Not Available

    1993-02-01

    The Sanitary Landfill at the Savannah River Site (SRS) is composed of the original 32-acre landfill, plus expansion areas to the north and south that added 16 and 22 acres, respectively, to the facility. The landfill is subject to the requirements of the Resource Conservation and Recovery Act and currently operates under South Carolina Department of Health and Environmental Control (SCDHEC) Domestic Waste Permit 87A. Fifty-seven wells of the LFW series monitor the groundwater quality in Steed Pond Aquifer (formerly Aquifer Zone I/IIC[sub 2]) (Water Table) beneath the Sanitary Landfill. These wells are sampled quarterly for certain indicator parameters, inorganics, metals, radionuclides, volatile organics, and other constituents as part of the SRS Groundwater Monitoring Program and to comply with the SCDHEC domestic waste permit. This report reviews the 1992 activities of the SRS Groundwater Monitoring Program.

  5. Where Should the Landfill Go?

    ERIC Educational Resources Information Center

    Fazio, Rosario P.; McFaden, Dennis

    1993-01-01

    Describes a project where students were involved in finding the most suitable site for a landfill in their community. This two-month project was conducted using team teaching. Two twelfth grade geoscience classes were involved. (PR)

  6. Where Should the Landfill Go?

    ERIC Educational Resources Information Center

    Fazio, Rosario P.; McFaden, Dennis

    1993-01-01

    Describes a project where students were involved in finding the most suitable site for a landfill in their community. This two-month project was conducted using team teaching. Two twelfth grade geoscience classes were involved. (PR)

  7. Fibrogenesis by mineral fibres: an in-vitro study of the roles of the macrophage and fibre length.

    PubMed Central

    Aalto, M.; Heppleston, A. G.

    1984-01-01

    Evidence on the mechanism by which inhaled mineral fibres lead to pulmonary fibrosis has not been forthcoming. As with silica, a biphasic cell culture system was required to distinguish phagocytosis from collagen formation. Synthesis of total protein and collagen by rat fibroblasts was estimated by incorporation of labelled proline after treatment with the medium from rat peritoneal macrophages that had been cultured in the presence of different types of mineral fibre. The influence of fibre length was also examined. All the main varieties of asbestos reacted with macrophages to produce or release a fibrogenic factor. However, chrysotile and the longer amosite fibres evoked the response only after prolonging the period of incubation with macrophages, presumably by permitting more complete phagocytosis of curled or longer fibres. Short amosite fibres proved to be more active than longer ones and under certain conditions were as potent as quartz. Fibrous glass also possessed stimulatory properties and again a sample having a short length gave a stronger response than a long one. Collagen formation by asbestos thus appears to be mediated by a macrophage factor, so operating in a manner similar to that previously demonstrated for quartz. The conventional view that short fibres are comparatively insignificant in asbestos fibrogenesis cannot, on the present evidence, be sustained. Furthermore, it should not be assumed than man-made mineral fibres of respirable diameter are innocuous or that short ones can be ignored. PMID:6696832

  8. FRD in optical fibres at low temperatures: investigations for Gemini's Wide-field Fibre Multi-Object Spectrograph

    NASA Astrophysics Data System (ADS)

    de Oliveira, A. C.; de Oliveira, L. S.; Dos Santos, J. B.; Arruda, M. V.; Dos Santos, L. G. C.; Rodrigues, F.; de Castro, F. L. F.

    2011-06-01

    While there is no direct evidence for the deterioration in Focal Ratio Degradation (FRD) of optical fibres in severe temperature gradients, the fibre ends inserted into metallic containment devices such as steel ferrules can be a source of stress, and hence increased FRD at low temperatures. In such conditions, instruments using optical fibres may suffer some increase in FRD and consequent loss of system throughput when they are working in environments with significant thermal gradients, a common characteristic of ground-based observatories. In this paper we present results of experiments with optical fibres inserted in different materials as a part of our prototyping study for Gemini's Wide-field Multi-Object Spectrograph (WFMOS) project. Thermal effects and the use of new holding techniques will be discussed in the context of Integral Field Units and multi-fibres systems. In this work, we have used careful methodologies that give absolute measurements of FRD to quantify the advantages of using epoxy-based composites rather than metals as support structures for the fibre ends. This is shown to be especially important in minimizing thermally induced stresses in the fibre terminations. Not only is this important for optimizing fibre spectrograph performance but the benefits of using such materials are demonstrated in the minimization of positional variations and the avoidance of metal-to-glass delamination. Furthermore, by impregnating the composites with small zirconium oxide particles the composite materials supply their own fine polishing grit which aids significantly to the optical quality of the finished product.

  9. Fibrogenesis by mineral fibres: an in-vitro study of the roles of the macrophage and fibre length.

    PubMed

    Aalto, M; Heppleston, A G

    1984-02-01

    Evidence on the mechanism by which inhaled mineral fibres lead to pulmonary fibrosis has not been forthcoming. As with silica, a biphasic cell culture system was required to distinguish phagocytosis from collagen formation. Synthesis of total protein and collagen by rat fibroblasts was estimated by incorporation of labelled proline after treatment with the medium from rat peritoneal macrophages that had been cultured in the presence of different types of mineral fibre. The influence of fibre length was also examined. All the main varieties of asbestos reacted with macrophages to produce or release a fibrogenic factor. However, chrysotile and the longer amosite fibres evoked the response only after prolonging the period of incubation with macrophages, presumably by permitting more complete phagocytosis of curled or longer fibres. Short amosite fibres proved to be more active than longer ones and under certain conditions were as potent as quartz. Fibrous glass also possessed stimulatory properties and again a sample having a short length gave a stronger response than a long one. Collagen formation by asbestos thus appears to be mediated by a macrophage factor, so operating in a manner similar to that previously demonstrated for quartz. The conventional view that short fibres are comparatively insignificant in asbestos fibrogenesis cannot, on the present evidence, be sustained. Furthermore, it should not be assumed than man-made mineral fibres of respirable diameter are innocuous or that short ones can be ignored.

  10. Blue Up-Conversion Fibre Laser Pumped by a 1120-nm Raman Fibre Laser

    NASA Astrophysics Data System (ADS)

    Qin, Guan-Shi; Huang, Sheng-Hong; Feng, Yan; Shirakawa, A.; Musha, M.; Ueda, Ken-ichi

    2005-05-01

    A Tm3+-doped ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fibre up-conversion laser pumped by a 1120-nm Raman fibre laser is demonstrated with blue output power levels up to 116 mW. For the output mirror with 80% reflectivity, the slope efficiency is about 15%, the optical-to-optical conversion efficiency is 11%, and the maximum un-saturated output power is 116 mW. For 60% reflectivity, the slope efficiency is about 18% and the optical-to-optical conversion efficiency is 12%, whilst the maximum saturated output power is about 80 mW due to the existence of photo-degradation effect in Tm3+ doped ZBLAN glass fibre.

  11. PRACTICE REVIEW OF FIVE BIOREACTOR/RECIRCULATION LANDFILLS

    EPA Science Inventory

    Six bioreactor landfills were analyzed to provide a perspective of current practice and technical issues that differentiate bioreactor landfills from conventional landfills. Five of the bioreactor landfills were anaerobic and one was aerated. In one case, nearly identical cells e...

  12. PRACTICE REVIEW OF FIVE BIOREACTOR/RECIRCULATION LANDFILLS

    EPA Science Inventory

    Six bioreactor landfills were analyzed to provide a perspective of current practice and technical issues that differentiate bioreactor landfills from conventional landfills. Five of the bioreactor landfills were anaerobic and one was aerated. In one case, nearly identical cells e...

  13. Fibre and enteral nutrition.

    PubMed Central

    Silk, D B

    1989-01-01

    The recent launch of a number of fibre enriched polymeric diet in the United States and Europe has stimulated considerable interest in the topic of fibre and enteral nutrition, and several commercial concerns appear to be under considerable pressures from their consumers to produce similar products. As a means of identifying areas of potential application of fibre to enteral nutrition some of the recent knowledge gained about the physical properties of dietary fibre and the processes involved in the intestinal assimilation of fibre has been reviewed. Two areas of interest are identifiable. The first relates to the bulking properties of fibre and the application of this to the regulation of bowel function in enterally fed patients. It is clear from the clinical studies that have been reviewed that there remains a paucity of controlled data, and a great deal more research is needed before widespread use of fibre supplemented diets can be supported. Perhaps of greater interest academically is the potentially beneficial effects that appear to be exerted by the VFA's, liberated as a consequence of colonic bacterial fermentation of fibre, on morphology and function of ileal and colonic mucosa. Although there are a number of potential applications of fibre supplemented enteral diets in this area, more research is required before any firm recommendations can be made about recommending their use. The one exception concerns patients with the nutritionally inadequate short bowel syndrome. There does seem to be sufficient experimental evidence to suggest that clinical studies should be commenced using a pectin supplemented predigested 'elemental' diet in these patients. Overall therefore, one is forced to conclude that the increasing interest and use of fibre supplemented enteral diets is being driven more by market than scientific forces. Nevertheless, the promotion of these diets has already provided a powerful stimulus to the scientific community, and it remains entirely

  14. A Model Recycling Program: UNC Takes Action as Landfill Space Shrinks and Costs Rise.

    ERIC Educational Resources Information Center

    Sherman, Rhonda L.

    1991-01-01

    The University of North Carolina responded to escalating waste disposal costs and shrinking landfill space with a structured program of recycling, including a mobile recycling drop, student family housing recycling, a newspaper drop-off site, high-volume glass pick-up, high-volume newspaper pick-up, and cardboard recycling. Campus-wide cooperation…

  15. A Model Recycling Program: UNC Takes Action as Landfill Space Shrinks and Costs Rise.

    ERIC Educational Resources Information Center

    Sherman, Rhonda L.

    1991-01-01

    The University of North Carolina responded to escalating waste disposal costs and shrinking landfill space with a structured program of recycling, including a mobile recycling drop, student family housing recycling, a newspaper drop-off site, high-volume glass pick-up, high-volume newspaper pick-up, and cardboard recycling. Campus-wide cooperation…

  16. Methane emissions from MBT landfills.

    PubMed

    Heyer, K-U; Hupe, K; Stegmann, R

    2013-09-01

    Within the scope of an investigation for the German Federal Environment Agency ("Umweltbundesamt"), the basics for the estimation of the methane emissions from the landfilling of mechanically and biologically treated waste (MBT) were developed. For this purpose, topical research including monitoring results regarding the gas balance at MBT landfills was evaluated. For waste treated to the required German standards, a methane formation potential of approximately 18-24 m(3)CH(4)/t of total dry solids may be expected. Monitoring results from MBT landfills show that a three-phase model with differentiated half-lives describes the degradation kinetics in the best way. This is due to the fact that during the first years of disposal, the anaerobic degradation processes still proceed relatively intensively. In addition in the long term (decades), a residual gas production at a low level is still to be expected. Most of the soils used in recultivation layer systems at German landfills show a relatively high methane oxidation capacity up to 5 l CH(4)/(m(2)h). However, measurements at MBT disposal sites indicate that the majority of the landfill gas (in particular at non-covered areas), leaves the landfill body via preferred gas emission zones (hot spots) without significant methane oxidation. Therefore, rather low methane oxidation factors are recommended for open and temporarily covered MBT landfills. Higher methane oxidation rates can be achieved when the soil/recultivation layer is adequately designed and operated. Based on the elaborated default values, the First Order Decay (FOD) model of the IPCC Guidelines for National Greenhouse Gas Inventories, 2006, was used to estimate the methane emissions from MBT landfills. Due to the calculation made by the authors emissions in the range of 60,000-135,000 t CO(2-eq.)/a for all German MBT landfills can be expected. This wide range shows the uncertainties when the here used procedure and the limited available data are applied

  17. Results of current intraperitoneal carcinogenicity studies with mineral and vitreous fibres.

    PubMed

    Roller, M; Pott, F; Kamino, K; Althoff, G H; Bellmann, B

    1996-01-01

    The study includes some 50 groups of male or female Wistar rats tested in three series. Except for one untreated group and 3 vehicle control groups, the animals were injected intraperitoneally (i.p.) once or repeatedly with dust suspensions and then examined, after lifetime observation up to 30 months, for tumours in the abdominal cavity. 1 granular dust (silicon carbide), 2 asbestos dusts (crocidolite, tremolite) and 11 vitreous fibre dust samples were administered. 5 of the vitreous fibre types were fine fibre fractions from 4 commercial insulation wools and 1 experimental wool, the others were prepared by milling glass microfibres, which have, per se, a small diameter range. The dosage per rat differed over a wide range in accordance with experience from earlier studies. The lowest dose was 0.04 x 10(9) crocidolite fibres in 0.5 mg dust, and the highest amounted to 20 x 10(9) glass fibres in 1000 mg divided into 40 weekly injections. Two mesotheliomas were found in a total of 395 rats treated with saline or granular silicon carbide (250 or 1000 mg). Eleven fibre dusts produced dose-dependent mesotheliomas at rates of up to 97 %, but the calculated fibre number > 5 micrometers in length required for inducing a 25 % tumour risk differed between the fibre samples tested in the relation of 1 to about 1000. UICC-like crocidolite heads the ranking order; the glass fibre B-01, which possesses a low durability in the body, ends it together with a rather thin sample of glass fibre type B-09. The stone fibre MMVF-21 takes a high place in the ranking order, similar to the tremolite sample. The results correspond to those of earlier i.p. tests.

  18. Town of Edinburg landfill reclamation demonstration project

    SciTech Connect

    Not Available

    1992-05-15

    Landfill reclamation is the process of excavating a solid waste landfill to recover materials, reduce environmental impacts, restore the land resource, and, in some cases, extend landfill life. Using conventional surface mining techniques and specialized separation equipment, a landfill may be separated into recyclable material, combustible material, a soil/compost fraction and residual waste. A landfill reclamation demonstration project was hosted at the Town of Edinburg municipal landfill in northwest Saratoga County. The report examines various separation techniques employed at the site and appropriate uses for reclaimed materials. Specifications regarding engineered work plans, health and safety monitoring, and contingency preparedness are discussed. Major potential applications and benefits of using landfill reclamation technology at existing landfills are identified and discussed. The research and development aspect of the report also examines optimal screening technologies, site selection protocol and the results of a test burn of reclaimed waste at a waste-to-energy facility. Landfill reclamation costs are developed, and economic comparisons are made between reclamation costs and conventional landfill closure costs, with key criteria identified. The results indicate that, although dependent on site-specific conditions and economic factors, landfill reclamation can be a technically and economically feasible alternative or companion to conventional landfill closure under a range of favorable conditions. Feasibility can be determined only after an investigation of the variety of landfill conditions and reclamation options.

  19. Entropic shrinkage of an oxide glass

    NASA Astrophysics Data System (ADS)

    Inaba, Seiji; Hosono, Hideo; Ito, Setsuro

    2015-03-01

    Entropic elasticity, a property typical of rubbers and well known in organic polymers with appropriate network structures, is not known to occur in oxide glasses. Here, we report the occurrence of entropic elasticity in phosphate-glass fibres with highly anisotropic structures, drawn by mechanical elongation from supercooled liquids. We observed a large lengthwise shrinkage of ~35% for phosphate glasses with an enhanced one-dimensional structure, as well as a distinct endotherm on reheating them up to temperatures between that of the glass transition temperature and the softening temperature. Our results strongly suggest the possibility of designing oxide glasses with a rubbery nature at high temperatures.

  20. Entropic shrinkage of an oxide glass.

    PubMed

    Inaba, Seiji; Hosono, Hideo; Ito, Setsuro

    2015-03-01

    Entropic elasticity, a property typical of rubbers and well known in organic polymers with appropriate network structures, is not known to occur in oxide glasses. Here, we report the occurrence of entropic elasticity in phosphate-glass fibres with highly anisotropic structures, drawn by mechanical elongation from supercooled liquids. We observed a large lengthwise shrinkage of ~35% for phosphate glasses with an enhanced one-dimensional structure, as well as a distinct endotherm on reheating them up to temperatures between that of the glass transition temperature and the softening temperature. Our results strongly suggest the possibility of designing oxide glasses with a rubbery nature at high temperatures.

  1. A viscoelastic-viscoplastic model for short-fibre reinforced polymers with complex fibre orientations

    NASA Astrophysics Data System (ADS)

    Nciri, M.; Notta-Cuvier, D.; Lauro, F.; Chaari, F.; Zouari, B.; Maalej, Y.

    2015-09-01

    This paper presents an innovative approach for the modelling of viscous behaviour of short-fibre reinforced composites (SFRC) with complex distributions of fibre orientations and for a wide range of strain rates. As an alternative to more complex homogenisation methods, the model is based on an additive decomposition of the state potential for the computation of composite's macroscopic behaviour. Thus, the composite material is seen as the assembly of a matrix medium and several linear elastic fibre media. The division of short fibres into several families means that complex distributions of orientation or random orientation can be easily modelled. The matrix behaviour is strain-rate sensitive, i.e. viscoelastic and/or viscoplastic. Viscoelastic constitutive laws are based on a generalised linear Maxwell model and the modelling of the viscoplasticity is based on an overstress approach. The model is tested for the case of a polypropylene reinforced with short-glass fibres with distributed orientations and subjected to uniaxial tensile tests, in different loading directions and under different strain rates. Results demonstrate the efficiency of the model over a wide range of strain rates.

  2. Radiation curing of carbon fibre composites

    NASA Astrophysics Data System (ADS)

    Spadaro, G.; Alessi, S.; Dispenza, C.; Sabatino, M. A.; Pitarresi, G.; Tumino, D.; Przbytniak, G.

    2014-01-01

    Epoxy/carbon fibre reinforced composites were produced by means of e-beam irradiation through a pulsed 10 MeV electron beam accelerator. The matrix consisted of a difunctional epoxy monomer (DGEBA) and an initiator of cationic polymerisation, while the reinforcement was a unidirectional high modulus carbon fibre fabric. Dynamic mechanical thermal analysis was carried out in order to determine the cross-linking degree. The analysis pointed out a nonuniformity in the cross-linking degree of the e-beam cured panels, with the formation of clusters at low Tg (glass transition temperature) and clusters at high Tg. An out-of-mould post irradiation thermal treatment on e-beam cured samples provides a higher uniformity in the network although some slight degradation effects. Mode I delamination fracture toughness and Interlaminar Shear Strength (ISS) were also investigated by means of Double Cantilever Beam (DCB) and Short Beam Shear tests, respectively. Results from this mechanical characterisation allowed to correlate fracture toughness of the bulk matrix resin, cross-linking density and fibre/matrix interaction to the delamination fracture behaviour of the fibre reinforced material.

  3. A novel technique for active fibre production

    NASA Astrophysics Data System (ADS)

    Renner-Erny, Ruth; Di Labio, Loredana; Lüthy, Willy

    2007-04-01

    Active fibre devices are conventionally manufactured using MCVD technique. Recently it has been shown that nearly equivalent results can also be obtained with sol-gel technology. Now we present a novel technique allowing simplification of the manufacturing process even more. The required constituents are mixed in the form of dry micro- and nano-sized particles. A silica glass tube forming the future core region of a fibre preform is filled with a powder mix of SiO 2, 1% Nd (as Nd 2O 3) and 10% Al (as Al 2O 3). This tube is mounted in the centre of a larger tube forming the future cladding. The empty space between the two tubes is filled with SiO 2 powder. After preheating, the evacuated preform is drawn to a fibre. A length of 45 cm, cladding-pumped with a diode laser at 808 nm as well as a core-pumped fibre of 5.1 cm length showed laser action between 1.05 and 1.1 μm.

  4. New generation of optical fibres

    SciTech Connect

    Dianov, E M; Semjonov, S L; Bufetov, I A

    2016-01-31

    The growing need for information in contemporary society is the motivating force behind the development of fibre optics in general and optical fibre communications in particular. Intensive research effort has been concentrated on designing new types of optical fibres and extending their application field. This paper reviews results of research on new types of optical fibres: bismuthdoped active fibres, multicore fibres and hollow-core fibres, which can be used as key components of systems that ensure further increase in optical information transfer rate. (invited paper)

  5. Evaluation Of Landfill Gas Decay Constant For Municipal Solid Waste Landfills Operated As Bioreactors

    EPA Science Inventory

    Prediction of the rate of gas production from bioreactor landfills is important to optimize energy recovery and to estimate greenhouse gas emissions. Landfill gas (LFG) composition and flow rate were monitored for four years for a conventional and two bioreactor landfill landfil...

  6. Evaluation Of Landfill Gas Decay Constant For Municipal Solid Waste Landfills Operated As Bioreactors

    EPA Science Inventory

    Prediction of the rate of gas production from bioreactor landfills is important to optimize energy recovery and to estimate greenhouse gas emissions. Landfill gas (LFG) composition and flow rate were monitored for four years for a conventional and two bioreactor landfill landfil...

  7. Landfill to Learning Facility

    NASA Astrophysics Data System (ADS)

    Venner, Laura

    2008-05-01

    Engaging "K-to-Gray” audiences (children, families, and older adults) in scientific exploration and discovery is the main goal of the NJMC Center for Environmental and Scientific Education and the William D. McDowell Observatory located in Lyndhurst, NJ. Perched atop a closed and reclaimed municipal solid waste landfill, our new LEED - certified building (certification pending) and William D. McDowell observatory will bring hands-on scientific experiences to the 25,000 students and 3,000 adults that visit our site from the NY/NJ region each year. Our programs adhere to the New Jersey Core Curriculum Content Standards and are modified for accessibility for the underserved communities that visit us, specifically those individuals that have mobility, sensory, and/or cognitive ability differences. The programs are conducted in a classroom setting and are designed to nourish the individual's inquisitive nature and provide an opportunity to function as a scientist by, making observations, performing experiments and recording data. We have an $850,000, three year NSF grant that targets adults with disabilities and older adults with age related limitations in vision, hearing, cognition and/or mobility. From dip netting in the marsh to astronomical investigation of the cosmos, the MEC/CESE remains committed to reaching the largest audience possible and leaving them with a truly exceptional scientific experience that serves to educate and inspire.

  8. An Historic Overview of the Development of Fibre Metal Laminates

    NASA Astrophysics Data System (ADS)

    Vermeeren, C. A. J. R.

    2003-07-01

    In this paper a brief overview of the history of Fibre Metal Laminates Arall and Glare is given as background information for the other, technical articles in this journal. The story of the development of Fibre Metal Laminates is rather a unique story in the history of aircraft materials: A university laboratory invented, developed and certified an aircraft material. Many parties were involved naturally, yet the very heart of the activity was the Structures and Materials Laboratory of the Faculty of Aerospace Engineering of Delft University of Technology in The Netherlands. At the break of the world's largest passenger transport aircraft, the Airbus A380, in which a substantial part of the fuselage will be made of Glare, the glass fibre-aluminium version of Fibre Metal Laminates, it is a good moment to tell some of its history.

  9. Landfill mining: Giving garbage a second chance

    SciTech Connect

    Cobb, C.C.; Ruckstuhl, K. )

    1988-08-01

    Some communities face the problems of lack of landfill space and lack of landfill cover dirt. In some cases, existing landfills may be mined to reclaim dirt for use as cover material and to recover space for reuse. Such mining also has the potential of recovering recyclables and incinerator fuels. Machinery to reclaim refuse deposits, and their heterogeneous composted ingredients, was successfully tested at two Florida landfills in June 1987. One of the Florida mining tests, at the Collier County landfill near the city of Naples, had goals of demonstrating an economical mechanical system to separate the depository's ingredients into usable or redisposable components, and to see if the method could enable the county to avoid the expenses associated with permanent closure of a full landfill. This paper describes the history of the Collier County landfill, the equipment and feasibility test, economics, the monitoring of odors, landfill gas, and heavy metals, and results of the test.

  10. Compaction in optical fibres and fibre Bragg gratings under nuclear reactor high neutron and gamma fluence

    SciTech Connect

    Remy, L.; Cheymol, G.; Morana, A.; Marin, E.; Girard, S.

    2015-07-01

    In the framework of the development by CEA and SCK.CEN of a Fabry Perot Sensor (FPS) able to measure dimensional changes in Material Testing Reactor (MTR), the first goal of the SAKE 1 (Smirnof extention - Additional Key-tests on Elongation of glass fibres) irradiation was to measure the linear compaction of single mode fibres under high fast neutron fluence. Indeed, the compaction of the fibre which forms one side of the Fabry Perot cavity, may in particular cause a noticeable measurement error. An accurate quantification of this effect is then required to predict the radiation-induced drift and optimize the sensor design. To achieve this, an innovative approach was used. Approximately seventy uncoated fibre tips (length: 30 to 50 mm) have been prepared from several different fibre samples and were installed in the SCK.CEN BR2 reactor (Mol Belgium). After 22 days of irradiation a total fast (E > 1 MeV) fluence of 3 to 5x10{sup 19} n{sub fast}/cm{sup 2}, depending on the sample location, was accumulated. The temperature during irradiation was 291 deg. C, which is not far from the condition of the intended FPS use. A precise measurement of each fibre tip length was made before the irradiation and compared to the post irradiation measurement highlighting a decrease of the fibres' length corresponding to about 0.25% of linear compaction. The amplitude of the changes is independent of the capsule, which could mean that the compaction effect saturates even at the lowest considered fluence. In the prospect of performing distributed temperature measurement in MTR, several fibre Bragg gratings written using a femtosecond laser have been also irradiated. All the gratings were written in radiation hardened fibres, and underwent an additional treatment with a procedure enhancing their resistance to ionizing radiations. A special mounting made it possible to test the reflection and the transmission of the gratings on fibre samples cut down to 30 to 50 mm. The comparison of

  11. Respiratory health effects of man-made vitreous (mineral) fibres.

    PubMed

    De Vuyst, P; Dumortier, P; Swaen, G M; Pairon, J C; Brochard, P

    1995-12-01

    The group of man-made mineral or vitreous fibres (MMMFs or MMVFs) includes glass wool, rock wool, slag wool, glass filaments and microfibres, and refractory ceramic fibres (RCFs). Experimental observations have provided evidence that some types of MMVF are bioactive under certain conditions. The critical role of size parameters has been demonstrated in cellular and animal experiments, when intact fibres are in direct contact with the target cells. It is, however, difficult to extrapolate the results from these studies to humans since they bypass inhalation, deposition, clearance and translocation mechanisms. Inhalation studies are more realistic, but show differences between animal species regarding their sensibility to tumour induction by fibres. Fibre biopersistence is an important factor, as suggested by recent inhalation studies, which demonstrate positive results with RCF for fibrosis, lung tumours and mesothelioma. There is no firm evidence that exposure to glass-, rock- and slag wool is associated with lung fibrosis, pleural lesions, or nonspecific respiratory disease in humans. Exposure to RCF could enhance the effects of smoking in causing airways obstruction. An elevated standard mortality ratio for lung cancer has been demonstrated in cohorts of workers exposed to MMVF, especially in the early technological phase of mineral (rock slag) wool production. During that period, several carcinogenic agents (arsenic, asbestos, polycyclic aromatic hydrocarbons (PAH)) were also present at the workplace and quantitative data about smoking and fibre levels are lacking. It is not possible from these data to determine whether the risk of lung cancer is due to the MMVFs themselves. No increased risk of mesothelioma has been demonstrated in the cohorts of workers exposed to glass-, slag- or rock wool. There are in fact insufficient epidemiological data available concerning neoplastic diseases in RCF production workers because of the small size of the workforce and the

  12. Electron beam irradiation in natural fibres reinforced polymers (NFRP)

    NASA Astrophysics Data System (ADS)

    Kechaou, B.; Salvia, M.; Fakhfakh, Z.; Juvé, D.; Boufi, S.; Kallel, A.; Tréheux, D.

    2008-11-01

    This study focuses on the electric charge motion in unsatured polyester and epoxy composites reinforced by natural fibres of Alfa type, treated by different coupling agents. The electric charging phenomenon is studied by scanning electron microscopy mirror effect (SEMME) coupled with the induced current method (ICM). Previously, using the same approach, glass fibre reinforced epoxy (GFRE) was studied to correlate mechanical [B. Kchaou, C. Turki, M. Salvia, Z. Fakhfakh, D. Tréheux, Composites Science and Technology 64 (2004) 1467], or tribological [B. Kchaou, C. Turki, M. Salvia, Z. Fakhfakh, D. Tréheux, Dielectric and friction behaviour of unidirectionalglass fibre reinforced epoxy (GFRE), Wear, 265 (2008) 763.] properties and dielectric properties. It was shown that the dielectric properties of the fibre-matrix interfaces play a significant role in the optimization of the composite. This result seems to be the same for natural fibre composites: the fibre-matrix interfaces allow a diffusion of the electric charges which can delocalize the polarization energy and consequently delay the damage of the composite. However, a non-suited sizing can lead to a new trapping of electric charges along these same interfaces with, as a consequence, a localization of the polarisation energy. The optimum composite is obtained for one sizing which helps, at the same time, to have a strong fibre-matrix adhesion and an easy flow of the electric charges along the interface.

  13. Landfill mining for resource recovery

    SciTech Connect

    Reith, C.C.

    1997-12-31

    Landfills are repositories of subeconomic resources. Landfill mining is an important enterprise that will someday return these resources to productive use, closing the loop on finite resources and stimulating economic development in communities near landfills. Secondary development of interred resources (landfill waste) will become economically viable as the environmental externalities of primary resource development -- e.g., the destruction of pristine habitat -- are more fully accounted for in programs of ecological design and design for environment. It is important to take an integrated and holistic approach to this new endeavor, which will be a complex assemblage of disciplines. Component disciplines include: resource economics, characterization, and excavation; contaminant control, and protection of environmental safety and health; material sorting, blending, and pretreatment; resource conversion, recovery, storage, and distribution; and reclamation for long-term land use. These technical elements must be addressed in close combination with compelling social issues such as environmental justice that may be especially critical in economically depressed communities surrounding today`s landfills.

  14. Landfill aeration for emission control before and during landfill mining.

    PubMed

    Raga, Roberto; Cossu, Raffaello; Heerenklage, Joern; Pivato, Alberto; Ritzkowski, Marco

    2015-12-01

    The landfill of Modena, in northern Italy, is now crossed by the new high velocity railway line connecting Milan and Bologna. Waste was completely removed from a part of the landfill and a trench for the train line was built. With the aim of facilitating excavation and further disposal of the material extracted, suitable measures were defined. In order to prevent undesired emissions into the excavation area, the aerobic in situ stabilisation by means of the Airflow technology took place before and during the Landfill Mining. Specific project features involved the pneumatic leachate extraction from the aeration wells (to keep the leachate table low inside the landfill and increase the volume of waste available for air migration) and the controlled moisture addition into a limited zone, for a preliminary evaluation of the effects on process enhancement. Waste and leachate were periodically sampled in the landfill during the aeration before the excavation, for quality assessment over time; the evolution of biogas composition in the landfill body and in the extraction system for different plant set-ups during the project was monitored, with specific focus on uncontrolled migration into the excavation area. Waste biological stability significantly increased during the aeration (waste respiration index dropped to 33% of the initial value after six months). Leachate head decreased from 4 to 1.5m; leachate recirculation tests proved the beneficial effects of moisture addition on temperature control, without hampering waste aerobization. Proper management of the aeration plant enabled the minimization of uncontrolled biogas emissions into the excavation area. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Compressive and flexural behaviour of fibre reinforced endodontic posts.

    PubMed

    Chieruzzi, Manila; Pagano, Stefano; Pennacchi, Manuela; Lombardo, Guido; D'Errico, Potito; Kenny, Josè M

    2012-11-01

    The aim of this study was to investigate the mechanical properties of five types of fibre-reinforced composite (FRC) posts and compare them with traditional metal post. Five FRC posts and a metallic post having different geometry and type of fibre (glass, carbon or quartz fibre) were loaded to failure in compression and bending. The transverse sections of FRC posts were observed using SEM to evaluate the fracture mode and the percentage of fibres (compared with burn-off test). Densities and voids content were also evaluated. Mechanical results were subjected to a one-way ANOVA and Tukey test (p<0.05). In compression, quartz fibre posts exhibited the greater maximum load and ultimate strength, carbon fibre posts showed a poor compressive behaviour. All posts had similar compressive moduli. Carbon posts showed the highest flexural properties (p<0.0001) while glass posts the greater maximum load. The fracture load values correlated to the diameters of posts showed a parabolic behaviour. The flexural strengths of all posts were four and seven times higher than dentine. The elastic moduli of almost all posts were similar to dentine. The compressive strengths were lower than flexural strengths. The fibre diameters ranged from 5.2 to 26 μm, the volume percentage of fibres was about 64%. The content of voids of some posts lower their mechanical behaviour. Compressive properties of FRC posts were lower than in bending. The flexural properties of FRC posts were higher than the metal post and similar to dentine. The mechanical behaviour is influenced by voids. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Advances in CO2 laser fabrication for high power fibre laser devices

    NASA Astrophysics Data System (ADS)

    Boyd, Keiron; Rees, Simon; Simakov, Nikita; Daniel, Jae M. O.; Swain, Robert; Mies, Eric; Hemming, Alexander; Clarkson, W. A.; Haub, John

    2016-03-01

    CO2 laser processing facilitates contamination free, rapid, precise and reproducible fabrication of devices for high power fibre laser applications. We present recent progress in fibre end-face preparation and cladding surface modification techniques. We demonstrate a fine feature CO2 laser process that yields topography significantly smaller than that achieved with typical mechanical cleaving processes. We also investigate the side processing of optical fibres for the fabrication of all-glass cladding light strippers and demonstrate extremely efficient cladding mode removal. We apply both techniques to fibres with complex designs containing multiple layers of doped and un-doped silica as well as shaped and circularly symmetric structures. Finally, we discuss the challenges and approaches to working with various fibre and glass-types.

  17. Ultrafast fibre lasers

    NASA Astrophysics Data System (ADS)

    Fermann, Martin E.; Hartl, Ingmar

    2013-11-01

    Ultrafast fibre lasers are fundamental building blocks of many photonic systems used in industrial and medical applications as well as for scientific research. Here, we review the essential components and operation regimes of ultrafast fibre lasers and discuss how they are instrumental in a variety of applications. In regards to laser technology, we discuss the present state of the art of large-mode-area fibres and their utilization in high-power, chirped-pulse amplification systems. In terms of commercial applications, we introduce industrial micromachining and medical imaging, and describe emerging applications in the mid-infrared and extreme-ultraviolet spectral regions, as facilitated by frequency shifting induced by fibre frequency combs.

  18. APPROACH FOR ESTIMATING GLOBAL LANDFILL METHANE EMISSIONS

    EPA Science Inventory

    The report is an overview of available country-specific data and modeling approaches for estimating global landfill methane. Current estimates of global landfill methane indicate that landfills account for between 4 and 15% of the global methane budget. The report describes an ap...

  19. METHANE PHYTOREMEDIATION BY VEGETATIVE LANDFILL COVER SYSTEMS

    EPA Science Inventory

    Landfill gas, consisting of methane and other gases, is produced from organic compounds degrading in landfills, contributes to global climate change, is toxic to various types of vegetation, and may pose a combustion hazard at higher concentrations. New landfills are required to ...

  20. Mining landfills for space and fuel

    SciTech Connect

    Flosdorf, H.W.; Alexieff, S.

    1993-03-01

    Lancaster County, Pennsylvania`s experiments with landfill reclamation are helping the county remain self-sufficient in managing its solid waste stream. Landfill mining is proving to be a worthwhile approach to extending landfill life and obtaining fuel for the county`s waste-to-energy plant.

  1. THE USEPA'S LANDFILL RESEARCH AND REGULATORY STRATEGY

    EPA Science Inventory

    The priorities and initiatives of Environmental Protection Agency's landfill research and regulatory program over the next five years will be described. This will include municipal solid waste landfills as well as abandoned hazardous waste landfills.

    Regarding municipals s...

  2. BIOREACTOR LANDFILLS, THEORETICAL ADVANTAGES AND RESEARCH CHALLENGES

    EPA Science Inventory

    Bioreactor landfills are municipal solid waste landfills that utilize bulk liquids in an effort to accelerate solid waste degradation. There are few potential benefits for operating a MSW landfill as a bioreactor. These include leachate treatment and management, increase in the s...

  3. APPROACH FOR ESTIMATING GLOBAL LANDFILL METHANE EMISSIONS

    EPA Science Inventory

    The report is an overview of available country-specific data and modeling approaches for estimating global landfill methane. Current estimates of global landfill methane indicate that landfills account for between 4 and 15% of the global methane budget. The report describes an ap...

  4. LANDFILL BIOREACTOR PERFORMANCE, SECOND INTERIM REPORT

    EPA Science Inventory

    A bioreactor landfill is a landfill that is operated in a manner that is expected to increase the rate and extent of waste decomposition, gas generation, and settlement compared to a traditional landfill. This Second Interim Report was prepared to provide an interpretation of fie...

  5. LANDFILL BIOREACTOR PERFORMANCE, SECOND INTERIM REPORT

    EPA Science Inventory

    A bioreactor landfill is a landfill that is operated in a manner that is expected to increase the rate and extent of waste decomposition, gas generation, and settlement compared to a traditional landfill. This Second Interim Report was prepared to provide an interpretation of fie...

  6. METHANE PHYTOREMEDIATION BY VEGETATIVE LANDFILL COVER SYSTEMS

    EPA Science Inventory

    Landfill gas, consisting of methane and other gases, is produced from organic compounds degrading in landfills, contributes to global climate change, is toxic to various types of vegetation, and may pose a combustion hazard at higher concentrations. New landfills are required to ...

  7. Landfills as sources of polyfluorinated compounds, polybrominated diphenyl ethers and musk fragrances to ambient air

    NASA Astrophysics Data System (ADS)

    Weinberg, Ingo; Dreyer, Annekatrin; Ebinghaus, Ralf

    2011-02-01

    In order to investigate landfills as sources of polyfluorinated compounds (PFCs), polybrominated diphenyl ethers (PBDEs) and synthetic musk fragrances to the atmosphere, air samples were simultaneously taken at two landfills (one active and one closed) and two reference sites using high volume air samplers. Contaminants were accumulated on glass fiber filters (particle phase) and PUF/XAD-2/PUF cartridges (gas phase), extracted by methyl-tert butyl ether/acetone (neutral PFCs), methanol (ionic PFCs) or hexane/acetone (PBDEs, musk fragrances), and detected by GC-MS (neutral PFCs, PBDEs, musk fragrances) or HPLC-MS/MS (ionic PFCs). Total concentrations ranged from 84 to 706 pg m -3 (volatile PFCs, gas phase), from landfill sites compared to corresponding reference sites. Concentrations determined at the active landfill were higher than those of the inactive landfill. Overall, landfills can be regarded as a source of synthetic musk fragrances, several PFCs and potentially of PBDEs to ambient air.

  8. Sustainable treatment of landfill leachate

    NASA Astrophysics Data System (ADS)

    Kamaruddin, Mohamad Anuar; Yusoff, Mohd. Suffian; Aziz, Hamidi Abdul; Hung, Yung-Tse

    2015-06-01

    Landfill leachate is a complex liquid that contains excessive concentrations of biodegradable and non-biodegradable products including organic matter, phenols, ammonia nitrogen, phosphate, heavy metals, and sulfide. If not properly treated and safely disposed, landfill leachate could be an impending source to surface and ground water contamination as it may percolate throughout soils and subsoils, causing adverse impacts to receiving waters. Lately, various types of treatment methods have been proposed to alleviate the risks of untreated leachate. However, some of the available techniques remain complicated, expensive and generally require definite adaptation during process. In this article, a review of literature reported from 2008 to 2012 on sustainable landfill leachate treatment technologies is discussed which includes biological and physical-chemical techniques, respectively.

  9. Geosynthetics conquer the landfill law

    SciTech Connect

    Derian, L.; Gharios, K.M. . Solid Waste Management Div.); Kavazanjian, E. Jr.; Snow, M.S. )

    1993-12-01

    Los Angeles' last operating landfill is undergoing a 4 million m[sup 3] expansion using innovative materials in the liner system to overcome difficult site conditions. The design represents the first approved alternative in California -- and perhaps in the nation -- to the Resource Conservation and Recovery Act's Subtitle D regulations for liner systems. This article examines the regulatory journey that led to approval and the liner's design and construction. Steep slopes at Los Angeles' only operating municipal solid-waste landfill (MSW) forced designers to use an innovative geosynthetic liner and leachate collection system. Its use sets a precedent for alternatives to the prescriptive regulations for liner systems present in Subtitle D of the Resource and Conservation Recovery Act (RCRA). To provide uninterrupted service at the landfill, design and construction proceeded concurrently with regulatory approval.

  10. Astronomy on a Landfill

    NASA Astrophysics Data System (ADS)

    Venner, Laura

    2008-09-01

    Engaging "K-to-Gray” audiences (children, families, and older adults) in astronomical activities is one of the main goals of the NJMC Center for Environmental and Scientific Education and the William D. McDowell Observatory located in Lyndhurst, NJ. Perched atop a closed and reclaimed municipal solid waste landfill, our new LEED - certified building (certification pending) and William D. McDowell observatory will assist in bringing the goals of IYA 2009 to the approximately 25,000 students and 15,000 adults that visit our site from the NY/NJ region each year. Diversifying our traditional environmental science offerings, we have incorporated astronomy into our repertoire with "The Sun Through Time” module, which includes storytelling, cultural astronomy, telescope anatomy, and other activities that are based on the electromagnetic spectrum and our current knowledge of the sun. These lessons have also been modified to bring astronomy to underserved communities, specifically those individuals that have dexterity or cognitive ability differences. The program is conducted in a classroom setting and is designed to meet New Jersey Core Curriculum Content Standards. With the installation of our new 20” telescope, students and amateur astronomers will be given the opportunity to perform rudimentary research. In addition, a program is in development that will allow individuals to measure local sky brightness and understand the effects of light pollution on astronomical viewing. Teaching astronomy in an urban setting presents many challenges. All individuals, regardless of ability level or location, should be given the opportunity to be exposed to the wonders of the universe and the MEC/CESE has been successful in providing those opportunities.

  11. Astronomy on a Landfill

    NASA Astrophysics Data System (ADS)

    Venner, Laura

    2008-05-01

    Engaging "K-to-Gray” audiences (children, families, and older adults) in astronomical activities is one of the main goals of the NJMC Center for Environmental and Scientific Education and the William D. McDowell Observatory located in Lyndhurst, NJ. Perched atop a closed and reclaimed municipal solid waste landfill, our new LEED - certified building (certification pending) and William D. McDowell observatory will assist in bringing the goals of IYA 2009 to the approximately 25,000 students and 3,000 adults that visit our site from the NY/NJ region each year. Diversifying our traditional environmental science offerings, we have incorporated astronomy into our repertoire with "The Sun Through Time” module, which includes storytelling, cultural astronomy, telescope anatomy, and other activities that are based on the electromagnetic spectrum and our current knowledge of the sun. These lessons have also been modified to bring astronomy to underserved communities, specifically those individuals that have dexterity or cognitive ability differences. The program is conducted in a classroom setting and is designed to meet New Jersey Core Curriculum Content Standards. With the installation of our new 20” telescope, students and amateur astronomers will be given the opportunity to perform rudimentary research. In addition, a program is in development that will allow individuals to measure local sky brightness and understand the effects of light pollution on astronomical viewing. Teaching astronomy in an urban setting presents many challenges. All individuals, regardless of ability level or location, should be given the opportunity to be exposed to the wonders of the universe and the MEC/CESE has been successful in providing those opportunities.

  12. Influence of fibre reinforcement on selected mechanical properties of dental composites.

    PubMed

    Niewczas, Agata M; Zamościńska, Jolanta; Krzyżak, Aneta; Pieniak, Daniel; Walczak, Agata; Bartnik, Grzegorz

    2017-01-01

    For splinting or designing adhesive bridges, reconstructive composite structures with increased mechanical properties owing to embedded reinforcement fibres are used. The aim of this article was to determine the influence of glass and aramid fibres on the mechanical strength of composites reinforced with these fibres. Two polymer-ceramic microhybrid materials: Boston and Herculite were tested. Three types of reinforcement fibres were used: aramid (Podwiązka) with a single layer weave, a single layer weave glass fibre (FSO) and triple layer weave glass fibre (FSO evo). Tests were conducted in accordance with the requirements of ISO 4049:2009. The following material types were chosen for research: Boston, Boston + Podwiązka, Herculite, Herculite + Podwiązka, Herculite + FSO and Herculite + FSO evo. The scope of research included: flexural strength B, bending modulus of elasticity εB and work to failure of the reinforced composite Wfb. Additionally, microscopic observations of fracture occurring in samples were made. In comparison: the Herculite (97.7 MPa) type with the Herculite + FSO evo (177.5 MPa) type was characterized by the highest strength. Fibre reinforcement resulted in decreasing the elasticity modulus: Herculite + reinforcement (6.86 GPa; 6.33 GPa; 6.11 GPa) in comparison with the Herculite (9.84 GPa) and respectively Boston + reinforcement (10.08 GPa) as compared with the Boston (11.81 GPa). Using glass fibres increases flexural strength of the test composites. Using aramid fibres does not change their strength. The elasticity modulus of the reinforced reconstructive structures decreases after application of either type of fibres. However, their resistance to the crack initiation increases.

  13. Case study of landfill reclamation at a Florida landfill site.

    PubMed

    Jain, Pradeep; Townsend, Timothy G; Johnson, Patrick

    2013-01-01

    A landfill reclamation project was considered to recover landfill airspace and soil, reduce future groundwater impacts by removing the waste buried in the unlined area, and optimize airspace use at the site. A phased approach was utilized to evaluate the technical and economic feasibility of the reclamation project; based on the results of these evaluations, approximately 6.8 ha of the unlined cells were reclaimed. Approximately 371,000 in-place cubic meters of waste was mined from 6.8 ha in this project. Approximately 230,600 cubic meters of net airspace was recovered due to beneficial use of the recovered final cover soil and reclaimed soil as intermediate and daily cover soil, respectively, for the current landfill operations. This paper presents the researchers' landfill reclamation project experience, including a summary of activities pertaining to reclamation operations, an estimation of reclamation rates achieved during the project, project costs and benefits, and estimated composition of the reclaimed materials. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Landfill Liners and Covers: Properties and Application to Army Landfills.

    DTIC Science & Technology

    1984-06-01

    sands and gravels were used for cover material. Several moni- toring points placed through and around the landfill defined the area of groundwater ... pollution . 2 1H. Dratfield and L. Mavtone, personal communication. 53 0 O GAS VENT 2’ FINAL COVER TREATMENT NEW- LAGOON W LT WAT _ LEACHATE COLLECTION

  15. Ways of Comparation of the Fibre Orientation in Injection Moulding Parts

    NASA Astrophysics Data System (ADS)

    Likavčan, Lukáš; Martinkovič, Maroš; Bílik, Jozef; Košík, Miroslav

    2014-12-01

    The fibre orientation in short fibre reinforced thermoplastics depends on injection moulding technology parameters. The aim of this paper is to propose possibilities for comparing fibre orientation of the real sample and the result from simulation software. Fibre orientation of selected injection moulding part is simulated. In some selected points secondorder tensor of orientation was estimated. Stereological metallography was used for possibility of comparison these results with experimental ones. An experimental result of estimation of degree of fibre orientation is described. The use of stereological metallography allows very simple and effective experimental estimation of short glass fibre orientation, which can be used for experimental verification of numerical simulation model, which can be optimized to obtained coincidence with experiments.

  16. Landfill gas cleanup for fuel cells

    SciTech Connect

    1995-08-01

    EPRI is to test the feasibility of using a carbonate fuel cell to generate electricity from landfill gas. Landfills produce a substantial quantity of methane gas, a natural by-product of decaying organic wastes. Landfill gas, however, contains sulfur and halogen compounds, which are known contaminants to fuel cells and their fuel processing equipment. The objective of this project is to clean the landfill gas well enough to be used by the fuel cell without making the process prohibitively expensive. The cleanup system tested in this effort could also be adapted for use with other fuel cells (e.g., solid oxide, phosphoric acid) running on landfill gas.

  17. Case studies in alternative landfill design

    SciTech Connect

    Barbagallo, J.C.; Druback, G.W.

    1995-12-31

    In the past, landfills or {open_quotes}dumps{close_quotes} were not highly regulated and typically did not require a detailed engineering design. However, landfills are no longer just holes in the ground, and landfill closures entail more than just spreading some dirt on top of piles of garbage. Today landfill design is a highly regulated, complex design effort that integrates soils and geosynthetics into systems aimed at providing long-term protection for the environment and surrounding communities. Integrating these complex design systems into the available landscape and exising landfill configuration often requires the designer go beyond the {open_quotes}typical{close_quotes} landfill and landfill closure design to satisfy regulations and provide cost-effective solutions.

  18. Landfill reclamation attracts attention and questions

    SciTech Connect

    Aquino, J.T.

    1994-12-01

    Landfill mining or reclamation has fit neatly into the recycling/reuse mindset. In heralding the first California landfill reclamation project at the Caspar Landfill municipal solid waste (MSW) site in May 1994, a California state official described it as ''win-win. Nobody loses''. Speaking at a session at the annual meeting of the Solid Waste Management Association of North America (SWANA), held August 2--6, 1994, Joanne R. Guerriero, senior project engineer, Malcolm Pirnie, Inc. (White Plains, NY), said landfill reclamation--the excavation of a landfill using conventional mining technology to recover and reuse resources--can: extend the life of existing landfill sites and reduce the need for siting new landfills; decrease the area requiring closure; remediate an environmental concern by removing a contaminant source; reclaim marketable recyclables; and capture energy through waste combustion.

  19. Use of the landfill water pollution index (LWPI) for groundwater quality assessment near the landfill sites.

    PubMed

    Talalaj, Izabela A; Biedka, Pawel

    2016-12-01

    The purpose of the paper is to assess the groundwater quality near the landfill sites using landfill water pollution index (LWPI). In order to investigate the scale of groundwater contamination, three landfills (E, H and S) in different stages of their operation were taken into analysis. Samples of groundwater in the vicinity of studied landfills were collected four times each year in the period from 2004 to 2014. A total of over 300 groundwater samples were analysed for pH, EC, PAH, TOC, Cr, Hg, Zn, Pb, Cd, Cu, as required by the UE legal acts for landfill monitoring system. The calculated values of the LWPI allowed the quantification of the overall water quality near the landfill sites. The obtained results indicated that the most negative impact on groundwater quality is observed near the old Landfill H. Improper location of piezometer at the Landfill S favoured infiltration of run-off from road pavement into the soil-water environment. Deep deposition of the groundwater level at Landfill S area reduced the landfill impact on the water quality. Conducted analyses revealed that the LWPI can be used for evaluation of water pollution near a landfill, for assessment of the variability of water pollution with time and for comparison of water quality from different piezometers, landfills or time periods. The applied WQI (Water Quality Index) can also be an important information tool for landfill policy makers and the public about the groundwater pollution threat from landfill.

  20. Resting calcium concentrations in isolated skeletal muscle fibres of dystrophic mice.

    PubMed Central

    Williams, D A; Head, S I; Bakker, A J; Stephenson, D G

    1990-01-01

    1. Single, intact muscle fibres were dissociated enzymatically from skeletal muscles of phenotypically normal (+/?) and dystrophic mice (129/ReJ dy/dy: Dystrophia muscularis), and resting Ca2+ levels were measured by image analysis of intracellular Fura-2 fluorescence in distinct parts of the fibres. 2. Fura-2 was introduced into fibres by ionophoresis with glass microelectrodes to concentrations of between 50 and 200 microM. Over this concentration range there was no apparent buffering of intracellular Ca2+ by Fura-2. 3. Fibres isolated from the soleus, flexor digitorum brevis (FDB) and extensor digitorum longus (EDL) muscles of normal animals maintained resting [Ca2+] of 106 +/- 2 nM. Ca2+ distributions within individual fibres were homogeneous. 4. Fibres from dystrophic animals maintained [Ca2+] that was elevated two- to fourfold in comparison to normal fibres. 5. The population of skeletal fibres from dystrophic mice which displayed morphology similar to that of fibres of normal animals were found to have Ca2+ levels that averaged 189 +/- 2 nM. The distribution of Ca2+ within these fibres appeared uniform. 6. The population of dystrophic fibres that possessed morphological abnormalities maintained even higher Ca2+ concentrations (368 +/- 3 nM). Several fibres from this morphological group displayed obvious heterogeneity in Ca2+ distribution with distinct, localized areas of higher Ca2+. 7. These results support the contention that Ca2+ homeostasis is markedly impaired in dystrophic muscle. The elevated Ca2+ levels are near the threshold for contraction and, together with severe morphological fibre abnormalities, are probably centrally involved in fibre necrosis apparent in muscular dystrophy. Images Fig. 2 Fig. 4 Fig. 5 (cont.) Fig. 5 PMID:2231412

  1. Landfill gas makes cheap fuel

    SciTech Connect

    Makansi, J.

    1984-08-01

    According to a recent study by the American Gas Assn (AGA), the amount of energy recovered from landfill gas has grown by nearly 800% over the last five years. There are nearly 30 active sites recovering energy across the US--mostly in California and the Northeast--and, based on one optimistic estimate, there are close to 3500 potential sites. Reasons for recovering landfill gas are numerous. One, communities are attracted by the additional revenue a successful landfill-gas recovery project brings; the gas can be sold to a naturalgas supplier, it can be burned in gas turbines or gas engines to generate electricity for sale to the local utility, and it can be used to generate steam for use at a nearby industrial or institutional site. Recovering methane helps reduce the odors produced from decomposing garbage which can be disturbing to people living in the vicinity of the landfill. It also helps reduce the chance of explosions--methane trapped beneath the surface can build up to dangerous levels.

  2. Biotechnology comes to landfill sites

    SciTech Connect

    Not Available

    1981-05-19

    The GLC's Aveley site in Essex is being managed for the production and collection of methane. Commercial tapping of methane for delivery to local firms is planned. It is estimated that Britain's 2.5 million cubic metres of landfill sites could contain methane reserves worth around number20M.

  3. Influence of fibre length, dissolution and biopersistence on the production of mesothelioma in the rat peritoneal cavity.

    PubMed

    Miller, B G; Searl, A; Davis, J M; Donaldson, K; Cullen, R T; Bolton, R E; Buchanan, D; Soutar, C A

    1999-04-01

    A range of respirable man-made mineral fibres were tested for evidence of carcinogenicity by injection into the peritoneal cavity of male SPF Wistar rats; and differences in carcinogenicity were related to the dimensions and biopersistence of the injected fibres. The fibres tested included an amosite asbestos, a silicon carbide whisker, a special purpose glass microfibre, and a range of other man-made vitreous fibres (MMVFs) and refractory ceramic fibres (RCFs) from the TIMA fibre repository. The injected dose of each was designed as the estimated mass required to contain 10(9) fibres > 5 microns in length, as determined by optical microscopy. The numbers of long fibres (> 15 microns) contained in these doses ranged across fibres from 0.1 x 10(9) to 0.8 x 10(9) fibres; the number of long fibres thinner than 0.95 micron ranged from 0.015 x 10(9) to 0.4 x 10(9). The treatment groups contained between 18 and 24 animals. Animals were killed when they showed signs of debilitation. At autopsy, the diagnosis of mesothelioma was usually obvious macroscopically. Otherwise, histological examination of peritoneal organs was used to search for early tumour development. Judged by median survival time, four of the fibre types, in the doses administered, presented higher mesothelioma activity than amosite asbestos. The other fibres tested were less carcinogenic than the amosite. Only a ceramic material derived by extreme heating to simulate the effect of furnace or oven conditions, produced no mesotheliomas. Attempts were made, using regression models, to relate these differences to fibre dimensions and to measures of durability from separate experiments. The results pointed principally to a link with the injected numbers of fibres > 20 microns in length and with biopersistence in the rat lung of fibres longer than 5 microns. Improved quantification of the relative importance of fibre dimensions and biopersistence indices requires experimentation with a range of doses.

  4. Vitrification as an alternative to landfilling of tannery sewage sludge

    SciTech Connect

    Celary, Piotr Sobik-Szołtysek, Jolanta

    2014-12-15

    Highlights: • The possibility of vitrification of tannery sewage sludge was investigated. • Glass cullet was substituted with different wastes of mineral character. • Component ratio in the processed mixtures was optimized. • Environmental safety of the acquired vitrificates was verified. • An alternative management approach of usually landfilled waste was presented. - Abstract: Due to high content of heavy metals such as chromium, tannery sewage sludge is a material which is difficult to be biologically treated as it is in the case of organic waste. Consequently, a common practice in managing tannery sewage sludge is landfilling. This poses a potential threat to both soil and water environments and it additionally generates costs of construction of landfills that meet specific environment protection requirements. Vitrification of this kind of sewage sludge with the addition of mineral wastes can represent an alternative to landfilling. The aim of this study was to investigate the possibility of obtaining an environmentally safe product by means of vitrification of tannery sewage sludge from a flotation wastewater treatment process and chemical precipitation in order to address the upcoming issue of dealing with sewage sludge from the tannery industry which will be prohibited to be landfilled in Poland after 2016. The focus was set on determining mixtures of tannery sewage sludge with additives which would result in the lowest possible heavy metal leaching levels and highest hardness rating of the products obtained from their vitrification. The plasma vitrification process was carried out for mixtures with various amounts of additives depending on the type of sewage sludge used. Only the materials of waste character were used as additives. One finding of the study was an optimum content of mineral additives in vitrified mixture of 30% v/v waste molding sands with 20% v/v carbonate flotation waste from the zinc and lead industry for the formulations with

  5. Fibre based cellular transfection.

    PubMed

    Tsampoula, X; Taguchi, K; Cizmár, T; Garces-Chavez, V; Ma, N; Mohanty, S; Mohanty, K; Gunn-Moore, F; Dholakia, K

    2008-10-13

    Optically assisted transfection is emerging as a powerful and versatile method for the delivery of foreign therapeutic agents to cells at will. In particular the use of ultrashort pulse lasers has proved an important route to transiently permeating the cell membrane through a multiphoton process. Though optical transfection has been gaining wider usage to date, all incarnations of this technique have employed free space light beams. In this paper we demonstrate the first system to use fibre delivery for the optical transfection of cells. We engineer a standard optical fibre to generate an axicon tip with an enhanced intensity of the remote output field that delivers ultrashort (~ 800 fs) pulses without requiring the fibre to be placed in very close proximity to the cell sample. A theoretical model is also developed in order to predict the light propagation from axicon tipped and bare fibres, in both air and water environments. The model proves to be in good agreement with the experimental findings and can be used to establish the optimum fibre parameters for successful cellular transfection. We readily obtain efficiencies of up to 57 % which are comparable with free space transfection. This advance paves the way for optical transfection of tissue samples and endoscopic embodiments of this technique.

  6. Mould design and manufacturing considerations of honeycomb biocomposites with transverse fibre direction for aerospace application

    NASA Astrophysics Data System (ADS)

    Manan, N. H.; Majid, D. L.; Romli, F. I.

    2016-10-01

    Sandwich structures with honeycomb core are known to significantly improve stiffness at lower weight and possess high flexural rigidity. They have found wide applications in aerospace as part of the primary structures, as well as the interior paneling and floors. High performance aluminum and aramid are the typical materials used for the purpose of honeycomb core whereas in other industries, materials such as fibre glass, carbon fibre, Nomex and also Kevlar reinforced with polymer are used. Recently, growing interest in developing composite structures with natural fibre reinforcement has also spurred research in natural fibre honeycomb material. The majority of the researches done, however, have generally emphasized on the usage of random chopped fibre and only a few are reported on development of honeycomb structure using unidirectional fibre as the reinforcement. This is mainly due to its processing difficulties, which often involve several stages to account for the arrangement of fibres and curing. Since the use of unidirectional fibre supports greater strength compared to random chopped fibre, a single-stage process in conjunction with vacuum infusion is suggested with a mould design that supports fibre arrangement in the direction of honeycomb loading.

  7. Fabrication of fibre reinforced nickel aluminide matrix composites by reactive processing

    SciTech Connect

    Downing, M.; Horsfall, I.

    1994-12-31

    This paper describes the fabrication by reactive processing of short, and continuous, alumina fibre reinforced nickel aluminide matrix composites. The fibre is introduced into the aluminide system to increase toughness and high temperature strength. The short fibre reinforced nickel aluminide is formed by squeeze casting a porous preform containing nickel powder and SAFFIL fibre with an aluminium or aluminium alloy melt. The continuous fibre reinforced nickel aluminide is formed by squeeze casting a jig containing nickel coated ALMAX fibre. The short fibre reinforced composite (containing 10% and 20% volume fibre) reacted during infiltration with an aluminium melt to form a single phase intermetallic. Using an aluminium-copper melt the intermetallic formation was inhibited and a multi-phase composite was obtained. A preliminary study into reactive processing of this system by utilising a hot isostatic pressing (HIP) cycle is presented. HIP was required to prevent the formation of porosity due to an imbalance in the diffusive mobility of the various components. It was found that HIP was only effective on canned samples, the preferred encapsulation material being glass. The continuous fibre reinforced composite did not react to an intermetallic phase when infiltrated with an aluminum melt. Use of an aluminum-copper melt resulted in partial nickel-melt reaction producing various nickel-aluminum (-copper) phases. HIP was then used to form a two phase intermetallic matrix with no evidence of fibre damage.

  8. Emissions from the Bena Landfill

    NASA Astrophysics Data System (ADS)

    Schafer, C.; Blake, D. R.; Hughes, S.

    2016-12-01

    In 2013, Americans generated 254 million tons of municipal solid waste (MSW). The gas generated from the decomposition of MSW is composed of approximately 50% methane, 50% carbon dioxide, and a small proportion of non-methane organic compounds (NMOCs). NMOCs constitute less than 1% of landfill emissions, but they can have a disproportionate environmental impact as they are highly reactive ozone precursors. During the 2016 Student Airborne Research Program (SARP), whole air samples were collected at the Bena landfill outside of Bakersfield, CA and throughout Bakersfield and analyzed using gas chromatography in order to quantify NMOC emissions. This area was determined to have elevated concentrations of benzene, trichloroethylene, and tetrachloroethylene, all of which are categorized by the EPA as hazardous to human health. Benzene was found to have a concentration of 145 ± 4 pptv, four times higher than the background levels in Bakersfield (36 ± 1 pptv). Trichloroethylene and tetrachloroethylene had concentrations of 18 ± 1 pptv and 31 ± 1 pptv which were 18 and 10 times greater than background concentrations, respectively. In addition, hydroxyl radical reactivity (ROH) was calculated to determine the potential for tropospheric ozone formation. The total ROH of the landfill was 7.5 ± 0.2 s-1 compared to total background ROH of 1.0 ± 0.1 s-1 . NMOCs only made up 0.6% of total emissions, but accounted for 67% of total ROH.These results can help to shape future landfill emission policies by highlighting the importance of NMOCs in addition to methane. More research is needed to investigate the ozone forming potential of these compounds at landfills across the country.

  9. Evaluation of Basalt Fibre Composites for Marine Applications

    NASA Astrophysics Data System (ADS)

    Davies, P.; Verbouwe, W.

    2017-07-01

    Basalt fibres offer potential for use in marine structures, but few data exist to evaluate the influence of seawater immersion on their mechanical behaviour. This paper provides the results from a study in which basalt fibre reinforced epoxy composites were aged in natural seawater at different temperatures. Tests were performed under quasi-static and cyclic loading, first in the as-received state then after saturation in natural seawater. Results are compared to those for an E-glass reinforced composite with the same epoxy matrix. They indicate similar mechanical performance for both materials after seawater saturation.

  10. Vitrification as an alternative to landfilling of tannery sewage sludge.

    PubMed

    Celary, Piotr; Sobik-Szołtysek, Jolanta

    2014-12-01

    Due to high content of heavy metals such as chromium, tannery sewage sludge is a material which is difficult to be biologically treated as it is in the case of organic waste. Consequently, a common practice in managing tannery sewage sludge is landfilling. This poses a potential threat to both soil and water environments and it additionally generates costs of construction of landfills that meet specific environment protection requirements. Vitrification of this kind of sewage sludge with the addition of mineral wastes can represent an alternative to landfilling. The aim of this study was to investigate the possibility of obtaining an environmentally safe product by means of vitrification of tannery sewage sludge from a flotation wastewater treatment process and chemical precipitation in order to address the upcoming issue of dealing with sewage sludge from the tannery industry which will be prohibited to be landfilled in Poland after 2016. The focus was set on determining mixtures of tannery sewage sludge with additives which would result in the lowest possible heavy metal leaching levels and highest hardness rating of the products obtained from their vitrification. The plasma vitrification process was carried out for mixtures with various amounts of additives depending on the type of sewage sludge used. Only the materials of waste character were used as additives. One finding of the study was an optimum content of mineral additives in vitrified mixture of 30% v/v waste molding sands with 20% v/v carbonate flotation waste from the zinc and lead industry for the formulations with flotation sewage sludge, and 45% v/v and 5% v/v, respectively, for precipitation sewage sludge. These combinations allowed for obtaining products with negligible heavy metal leaching levels and hardness similar to commercial glass, which suggests they could be potentially used as construction aggregate substitutes. Incineration of sewage sludge before the vitrification process lead to

  11. Fire Retardancy of Natural Fibre Reinforced Sheet Moulding Compound

    NASA Astrophysics Data System (ADS)

    Hapuarachchi, T. D.; Ren, G.; Fan, M.; Hogg, P. J.; Peijs, T.

    2007-07-01

    Due to environmental awareness and economical considerations, natural fibre reinforced polymer composites seem to present a viable alternative to synthetic fibre reinforced polymer composites such as glass fibres. This is a feasibility study to asses the potential application of natural fibre reinforced sheet moulding compound materials (NF-SMC) for the use in building applications, with particular emphases to their reaction to fire. The reinforcing fibres in this study were industrial hemp fibres. The cone calorimeter which asses the fire hazard of materials by Heat Release Rate (HRR) was used, radiant heat fluxes of 25 and 50 kW/m2 were utilised to simulate an ignition source and fully developed room fire conditions respectively. The results acquired here demonstrate that the NF-SMC can compete with current building materials in terms of their fire behaviour. The peak heat release value for the fire retardant (FR) NF-SMC was 176 kW/m2 conversely for a non-FR NF-SMC was 361 kW/m2.

  12. Parameters influencing the thermal expansion of polymers and fibre composites

    NASA Astrophysics Data System (ADS)

    Baschek, G.; Hartwig, G.

    Thermal expansion of polymers and fibre composites is an important design parameter in cryogenics. Measurements have been carried out with a laser interference dilatometer and an inductive dilatometer. Parameters which might influence the thermal expansion have been investigated. For polymers the influence of annealing has been studied. Annealing at a temperature near to the main glass transition yielded deviations of about 5% compared to those of untreated samples. The very large expansion of polymers can be drastically varied by reinforcement with fibres of different fibre arrangements. For carbon fibre angle-plies even negative expansion can be achieved (Humphreys, E.A. and Rosen, B.W., Properties analysis of laminates. In Engineered Materials Handbook, Vol. 1, Composites. ASM International, USA, 1987, p. 226). This behaviour arises from thermally induced shear stresses between the laminates. For carbon fibre reinforced polymers (CRPs) with different fibre angles the influences of thermal cycling, mechanical creep loading and geometrical shape (plates, half-tubes and tubes) on the expansion behaviour has been investigated. The expansion is influenced in a different manner by thermal cycling and mechanical creep loading. The largest effects arise from thermal cycling and mechanical creep loading of CRPs. The geometrical shape of the specimens influences the expansion behaviour remarkably. The expansion of tubes is smaller compared to that of plates. The reason is coupling of radial and azimuthal components existing for cylindrical samples.

  13. High volume individual fibre post versus low volume fibre post: the fracture load of the restored tooth.

    PubMed

    Hatta, Minori; Shinya, Akikazu; Vallittu, Pekka K; Shinya, Akiyoshi; Lassila, Lippo V J

    2011-01-01

    The purpose of this study was to evaluate the fracture loads of post-and-core systems with two different individually formed fibre post designs and polymerization conditions. Totally seventy-two (n=8/group) bovine teeth were cut and made up the root length of 15.0mm. They were divided into 3 main groups (Group A, B, C). A: one glass fibre post was light-cured before cementation, B: fibres were bundled to fill the entire root canal opening and light-cured before cementation, C: one unpolymerized glass fibre post was inserted into cement-filled root canal and light-cured with luting cement (ParaCem). Moreover specimens of each group were divided into 3 subgroups according to the post length: subgroup 1: 10mm; subgroup 2: 7.5mm; subgroup 3: 5.0mm. After cementation, the core was built up, and then made the composite resin crown (Filtek Z250). Fabricated specimen was loaded from 45° of palatal side at a crosshead speed of 1.0mm/min. The first load drop and maximum fracture loads were statistically analyzed by ANOVA and Tukey's test. Maximum fracture load of Group B (433 N) and C (418 N) are significantly higher than Group A (284 N) (p<0.01). Short post (5mm) provided higher fracture loads in all main groups, especially in Group C. Using short and thick fibre post system (the same diameter as the root canal) showed higher strength than one fibre post only. In addition, by curing the cement and the fibre material simultaneously, the strength of the restored tooth was increased. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. Evaluating the Marginal Integrity of Bulk Fill Fibre Reinforced Composites in Bio-mimetically Restored Tooth.

    PubMed

    Patnana, Arun Kumar; Vanga, V Narsimha Rao; Chandrabhatla, Srinivas Kumar

    2017-06-01

    Over the past years, composites in aesthetic dentistry are showing a considerable progress, but mechanical strength and polymerization shrinkage are the two main drawbacks, which limit their use in high stress bearing areas. To evaluate the marginal integrity of short glass fibre reinforced composite restorations, fibre reinforced composites with composite superficial layer, and fibre reinforced composites with underlying flowable composite layer. This study was done on twenty eight sound premolar teeth with standardized class V cavities restored under four groups as Group I: Particulate filler composite (Filtek Z 250 XT, 3M ESPE); Group II: Short glass fibre reinforced composite (everX Posterior, GC); Group III: Short glass fibre reinforced composite with an overlying layer of particulate filler composite; Group IV: Short glass fibre reinforced composite with an underlying layer of flowable composite (Filtek Z 250 XT, 3M ESPE). Test samples were immersed in a 2% methylene blue dye for 24 hours at 37°C and each tooth was sectioned bucco-lingually. Staining along the tooth restoration interface was recorded and results were analysed statistically using Independent sample t-test and Tukey's post-hoc one-way ANOVA. The results showed significant difference in the dye penetration between the restorative materials in the occlusal and gingival margins (p=0.02). Short fibre reinforced composites showed a statistically significant difference in the microleakage scores when compared with the particulate filler composites (p=0.01). Short glass fibre reinforced composite restorations showed an improved marginal integrity when compared to the traditional particulate filler composite restorations.

  15. Landfill reduction experience in The Netherlands.

    PubMed

    Scharff, Heijo

    2014-11-01

    Modern waste legislation aims at resource efficiency and landfill reduction. This paper analyses more than 20 years of landfill reduction in the Netherlands. The combination of landfill regulations, landfill tax and landfill bans resulted in the desired landfill reduction, but also had negative effects. A fierce competition developed over the remaining waste to be landfilled. In 2013 the Dutch landfill industry generated €40 million of annual revenue, had €58 million annual costs and therefore incurred an annual loss of €18 million. It is not an attractive option to prematurely end business. There is a risk that Dutch landfill operators will not be able to fulfil the financial obligations for closure and aftercare. Contrary to the polluter pays principle the burden may end up with society. EU regulations prohibiting export of waste for disposal are in place. Strong differentials in landfill tax rate between nations have nevertheless resulted in transboundary shipment of waste and in non-compliance with the self-sufficiency and proximity principles. During the transformation from a disposal society to a recycling society, it is important to carefully plan required capacity and to guide the reorganisation of the landfill sector. At some point, it is no longer profitable to provide landfill services. It may be necessary for public organisations or the state to take responsibility for the continued operation of a 'safety net' in waste management. Regulations have created a financial incentive to pass on the burden of monitoring and controlling the impact of waste to future generations. To prevent this, it is necessary to revise regulations on aftercare and create incentives to actively stabilise landfills.

  16. Radioluminescence of some optical fibres.

    PubMed

    Nowotny, R

    2007-02-21

    Measurement of radiation fields with small scintillators as detectors for radiation dose is an attractive method provided that the scintillator luminescence can be discriminated against other unwanted signals. In diagnostic radiology radioluminescence of the optical fibres required for a transmission of the luminescence to an optical detector is the only source for such an impairment of the signal. To find fibres with low radioluminosity a survey of ten commercial fibres including polystyrene (PS), polystyrene wavelength shifting fibres, poly-methylmetacrylate (PMMA) and silica as fibre core material was made. Measurements were made with two photomultipliers of different spectral response and a clinical x-ray unit. Lowest radioluminosity was obtained with PMMA fibres. Depending on spectral sensitivity of the multiplier clear PS fibres give five to ten times the luminescence of PMMA. From the silica fibres only one high-OH fibre gave comparable results for wavelength up to 520 nm. Wavelength shifting fibres and silica fibres with low OH-content show strong fluorescence and are not suitable fibre materials.

  17. Energy implications of glass-container recycling

    SciTech Connect

    Gaines, L L; Mintz, M M

    1994-03-01

    This report addresses the question of whether glass-container recycling actually saves energy. Glass-container production in 1991 was 10{sup 7} tons, with cullet making up about 30% of the input to manufacture. Two-thirds of the cullet is postconsumer waste; the remainder is in-house scrap (rejects). Most of the glass recycled is made into new containers. Total primary energy consumption includes direct process-energy use by the industry (adjusted to account for the efficiency of fuel production) plus fuel and raw-material transportation and production energies; the grand total for 1991 is estimated to be about 168 {times} 10{sup 12} Btu. The total primary energy use decreases as the percent of glass recycled rises, but the maximum energy saved is only about 13%. If distance to the landfill is kept fixed and that to the recovery facility multiplied by about eight, to 100 mi, a break-even point is reached, and recycling saves no energy. Previous work has shown that to save energy when using glass bottles, reuse is the clear choice. Recycling of glass does not save much energy or valuable raw material and does not reduce air or water pollution significantly. The most important impacts are the small reduction of waste sent to the landfill and increased production rates at glass plants.

  18. Surface emission of landfill gas from solid waste landfill

    NASA Astrophysics Data System (ADS)

    Park, Jin-Won; Shin, Ho-Chul

    The surface emission of landfill gas (LFG) was studied to estimate the amount of LFG efflux from solid waste landfills using an air flux chamber. LFG efflux increased as atmospheric temperature increased during the day, and the same pattern for the surface emission was observed for the change of seasons. LFG efflux rate decreased from summer through winter. The average LFG efflux rates of winter, spring and summer were 0.1584, 0.3013 and 0.8597 m 3 m -2 h -1 respectively. The total amount of surface emission was calculated based on the seasonal LFG efflux rate and the landfill surface area. From the estimates of LFG generation, it is expected that about 30% of the generated LFG may be released through the surface without extraction process. As forced extraction with a blower proceeded, the extraction well pressure decreased from 1100 to -100 mm H 2O, and the LFG surface efflux decreased markedly above 80%. Thus, the utilization of LFG by forced extraction would be the good solution for global warming and air pollution by LFG.

  19. Landfill reclamation feasibility study for the Montauk Landfill, town of East Hampton, New York. Final report

    SciTech Connect

    1998-01-01

    A landfill reclamation feasibility study was performed at Montauk Landfill in East Hampton, Long Island, New York. The purpose of the study was to determine whether landfill reclamation is a technically and economically feasible alternative to conventional landfill closure via capping. The technical feasibility of landfill reclamation at the site was determined from a field investigation in which the waste from different periods in the landfill`s history was characterized, the percent of reusable and recyclable materials determined, environmental hazards assessed, and throughput rates determined. Potential markets and/or uses for reclaimed materials were identified and estimates for the re-disposal of the residual waste were obtained from waste-to-energy facilities and offsite landfills.

  20. Glasses for seeing beyond visible.

    PubMed

    Zhang, XiangHua; Bureau, Bruno; Lucas, Pierre; Boussard-Pledel, Catherine; Lucas, Jacques

    2008-01-01

    Conventional glasses based on oxides have a transparency limited by phonon absorption in the near IR region and have a limited interest for analyzing information located far beyond the visible. The IR spectral domain is nevertheless of prime interest, since it covers fundamental wavelength ranges used for thermal imaging as well as molecular vibrational signatures. Besides spectacular advances in the field of IR detectors, the main significant progresses are related to the development of IR glass optics, such as lenses or IR optical fibres. The field of IR glasses is almost totally dominated by glasses formed from heavy atoms such as the chalcogens S, Se and Te. Their transparency extends up to 12, 16 and 28 microm for sulfide-, selenide- and the new generation of telluride-based glasses, respectively. They cover the atmospheric transparency domains, 3-5 and 8-13 microm, respectively, at which the IR radiation can propagate allowing thermal imaging and night-vision operations through thick layers of atmosphere. The development of new glass compositions will be discussed on the basis of structural consideration with the objective of moulding low-cost lenses for IR cameras used, for instance, in car-driving assistance. Additionally, multimode, single-index, optical fibres operating in the 3 to 12 microm window developed for in situ remote evanescent-wave IR spectroscopy will also be mentioned. The detection of molecular IR signatures is applied to environmental monitoring for investigating the pollution of underground water with toxic molecules. The extension of this technique to the investigation of biomolecules in three different studies devoted to liver tissues analysis, bio-film formation, and cell metabolism will also be discussed. Finally we will mention the developments in the field of single-mode fibres operating around 10 mum for the Darwin space mission, which is aiming at discovering, signs of biological life in telluric earth-like exoplanets throughout

  1. Landfill reduction experience in The Netherlands

    SciTech Connect

    Scharff, Heijo

    2014-11-15

    Highlights: • ‘Zero waste’ initiatives never consider risks, side effects or experience of achieved low levels of landfill. • This paper provides insight into what works and what not. • Where strong gradients in regulations and tax occur between countries, waste will find its way to landfills across borders. • Strong landfill reduction can create a fierce competition over the remaining waste to be landfilled resulting in losses. • At some point a public organisation should take responsibility for the operation of a ‘safety net’ in waste management. - Abstract: Modern waste legislation aims at resource efficiency and landfill reduction. This paper analyses more than 20 years of landfill reduction in the Netherlands. The combination of landfill regulations, landfill tax and landfill bans resulted in the desired landfill reduction, but also had negative effects. A fierce competition developed over the remaining waste to be landfilled. In 2013 the Dutch landfill industry generated €40 million of annual revenue, had €58 million annual costs and therefore incurred an annual loss of €18 million. It is not an attractive option to prematurely end business. There is a risk that Dutch landfill operators will not be able to fulfil the financial obligations for closure and aftercare. Contrary to the polluter pays principle the burden may end up with society. EU regulations prohibiting export of waste for disposal are in place. Strong differentials in landfill tax rate between nations have nevertheless resulted in transboundary shipment of waste and in non-compliance with the self-sufficiency and proximity principles. During the transformation from a disposal society to a recycling society, it is important to carefully plan required capacity and to guide the reorganisation of the landfill sector. At some point, it is no longer profitable to provide landfill services. It may be necessary for public organisations or the state to take responsibility for the

  2. Evaluation of the oncogenic potential of man-made vitreous fibres: the inhalation model.

    PubMed

    Bernstein, D M; Thevenaz, P; Fleissner, H; Anderson, R; Hesterberg, T W; Mast, R

    1995-10-01

    of ceramic, glass, rockwool and slagwood fibres have been evaluated with this model.

  3. Seismic evaluation of municipal solid waste landfill

    SciTech Connect

    Hovind, C.; Slyh, R.

    1995-12-31

    With the promulgation of the Resource Conservation and Recovery (RCRA) Subtitle D, landfills situated within seismic impact zones must be evaluated for seismic hazards to demonstrate that the containment structures of the landfill can resist the maximum horizontal acceleration in lithified earth materials (bedrock) for the site. If a landfill is sited on saturated soils, it must also be evaluated for liquefaction and lateral spreading. In 1994, EMCON evaluated the seismic hazard for a landfill located along the Columbia River in southwestern Washington. The landfill was founded on dredge fill over natural alluvial deposits. Laboratory testing and state-of-the-art engineering analyses indicated that the sand unit below the landfill had a high potential for liquefaction. The seismic hazard evaluation for the site included a site-specific seismic response analysis, a liquefaction potential analysis, and seismic stability and deformation analysis. The seismic response analysis was conducted for nonliquefied, partially liquefied, and fully liquefied foundation soil conditions. Results are described.

  4. Application of the CERCLA municipal landfill presumptive remedy to military landfills (interim guidance). Fact sheet

    SciTech Connect

    1996-04-01

    This directive highlights a step-by-step approach to determining when a specific military landfill is an appropriate site for application of the containment presumptive remedy. It identifies the characteristics of municipal landfills that are relevant to the applicability of the presumptive remedy, addresses characteristics specific to military landfills, outlines an approach to determining whether the presumptive remedy applies to a given military landfill, and discusses Administrative Record documentation requirements.

  5. Small fibre neuropathy.

    PubMed

    Cazzato, Daniele; Lauria, Giuseppe

    2017-10-01

    To provide a review on the state-of-art of clinical features, diagnostics, genetics and treatments of small fibre neuropathy (SFN). The spectrum of clinical features has been widened from the classical presentation of burning feet as length-dependent SFN to that of small fibre dysfunction and/or degeneration associated with focal, diffuse and episodic neuropathic pain syndromes. The involvement of small nerve fibres in neurodegenerative diseases has been further defined, challenging the relationship between neuropathic pain symptoms and small fibre loss. The clinical reliability of skin biopsy has been strengthened by the availability of normative values for both the immunohistochemistry techniques used and their comparison, and by side and short-term follow-up analyses. Corneal confocal microscopy has implemented its diagnostic potentiality because of the availability of age-adjusted and sex-adjusted normative values. Genetic studies expanded the panel on genes involved in SFN because of the discovery of new mutations in SCN10A and SCN11A, besides the first found in SCN9A, and identification of mutations in COL6A5 in patients with itching. In the last 5 years, the chapter of SFN has been widened by new clinical and genetics descriptions leading to a more comprehensive approach to patients in clinical practice and research.

  6. Two-photon absorption in SiO{sub 2}- and (SiO{sub 2} + GeO{sub 2})-based fibres at a wavelength of 349 nm

    SciTech Connect

    Chunaev, D S; Karasik, A Ya

    2014-06-30

    The nonlinear two-photon light absorption coefficients have been measured in an optical fibre with a quartz glass (SiO{sub 2}) core and in a fibre with a germanosilicate glass (SiO{sub 2} + GeO{sub 2}) core. The two-photon absorption coefficient β measured at a wavelength of 349 nm in the (SiO{sub 2} + GeO{sub 2})-based fibre (13.7 cm TW{sup -1}) multiply exceeds that for the pure quartz glass optical fibre (0.54 cm TW{sup -1}). (nonlinear optical phenomena)

  7. EVALUATION PLAN FOR TWO LARGE-SCALE LANDFILL BIOREACTOR TECHNOLOGIES

    EPA Science Inventory

    Abstract - Waste Management, Inc., is operating two long-term bioreactor studies at the Outer Loop Landfill in Louisville, KY, including facultative landfill bioreactor and staged aerobic-anaerobic landfill bioreactor demonstrations. A Quality Assurance Project Plan (QAPP) was p...

  8. Plants scrub landfill leachate clean

    SciTech Connect

    Not Available

    1980-09-01

    Leachate from the sanitary landfill in Barre, Mass., is collected in a series of holding lagoons. There, aquatic plants such as duckweed biodegrade and purify the wastewater. The plants saturate the leachate with oxygen, which speeds up aerobic oxidation by bacteria. The leachate is moved progressively through the series of lagoons, and the contents of the final lagoon are emptied into a trout pond. (3 photos)

  9. Photorefractive effect and photoinduced quadratic nonlinear susceptibility in germanosilicate fibres fabricated in nitrogen and helium atmospheres by the MCVD technique

    SciTech Connect

    Vasil'ev, Sergei A; Vechkanov, N N; Dianov, Evgenii M; Mashinsky, V M; Medvedkov, O I; Sazhin, O D; Gur'yanov, A N; Khopin, V F; Yatsenko, Yu P

    2000-09-30

    Single-mode optical fibres were fabricated from a germanosilicate glass by the method of modified chemical vapour deposition (MCVD), which used sintering of a porous glass in a reducing (helium or nitrogen-containing) atmosphere. The optical fibres exhibit a high photoinduced change in the refractive index and a high efficiency of recording quadratic nonlinear susceptibility compared to a standard germanosilicate fibre. Sintering, both in nitrogen and in helium atmospheres, was shown to increase the concentration of germanium oxygen-deficient centres in glass. It is likely that nitrogen enters into a germanosilicate glass in the concentration that is sufficient to modify the glass structure and to additionally increase its photosensitivity. The replacement of oxygen or silicon in the close vicinity of an oxygen vacancy by nitrogen may play a key role in the photosensitivity enhancement owing to the formation of additional valence bonds and blocking of recombination processes. (nonlinear optical phenomena)

  10. Nitrogen management in bioreactor landfills

    SciTech Connect

    Price, G. Alexander; Barlaz, Morton A.; Hater, Gary R

    2003-07-01

    One scenario for long-term nitrogen management in landfills is ex situ nitrification followed by denitrification in the landfill. The objective of this research was to measure the denitrification potential of actively decomposing and well decomposed refuse. A series of 10-l reactors that were actively producing methane were fed 400 mg NO{sub 3}-N /l every 48 h for periods of 19-59 days. Up to 29 nitrate additions were either completely or largely depleted within 48 h of addition and the denitrification reactions did not adversely affect the leachate pH. Nitrate did inhibit methane production, but the reactors recovered their methane-producing activity with the termination of nitrate addition. In well decomposed refuse, the nitrate consumption rate was reduced but was easily stimulated by the addition of either acetate or an overlayer of fresh refuse. Addition of acetate at five times the amount required to reduce nitrate did not lead to the production of NH{sub 4}{sup +} by dissimilatory nitrate reduction. The most probable number of denitrifying bacteria decreased by about five orders of magnitude during refuse decomposition in a reactor that did not receive nitrate. However, rapid denitrification commenced immediately with nitrate addition. This study shows that the use of a landfill as a bioreactor for the conversion of nitrate to a harmless byproduct, nitrogen gas, is technically viable.

  11. Innovative and effective landfill treatment

    SciTech Connect

    Butler, P.B.; Karmazyn, J.; Scrivner, N.C.

    1996-12-31

    An innovative and effective metals treatment technology was developed for a Superfund site landfill. The new landfill technology reduced the remedial cost of that operable unit from $34 million (MM) to $12 MM. In 1993, EPA issued a Record of Decision (ROD) for a Superfund site in Newport, Delaware. Among other remedies, deep-soil mixing was specified for a 16-acre landfill. New information on waste volumes developed in the remedial design phase increased the cost of the remedy from $14 MM to $34 MM. An alternative treatment technology was developed to immobilize the metal contaminants with no increase in volume. EPA was included early in the development to ensure the proposal would be focused on issues critical to its review and acceptance. EPA accepted this technology and issued an Explanation of Significant Differences decision. the new remedy is estimated to cost $12 MM. The constituents of concern at the site are primarily metals: barium, lead, zinc, and cadmium. A treatment technology was developed which employed straight-forward chemical precipitation: sulfate addition for barium and sulfide addition for lead, zinc, and cadmium. The combined effect of numerous competing chemical equilibrium effects was modeled with the Environmental Simulation Program (ESP), a state-of-the-art equilibrium simulation program from OLI Systems, Inc. Due to the potential effects of acid rain, limestone was added to the treatment plan.

  12. Mixed Waste Landfill Integrated Demonstration; Technology summary

    SciTech Connect

    1994-02-01

    The mission of the Mixed Waste Landfill Integrated Demonstration (MWLID) is to demonstrate, in contaminated sites, new technologies for clean-up of chemical and mixed waste landfills that are representative of many sites throughout the DOE Complex and the nation. When implemented, these new technologies promise to characterize and remediate the contaminated landfill sites across the country that resulted from past waste disposal practices. Characterization and remediation technologies are aimed at making clean-up less expensive, safer, and more effective than current techniques. This will be done by emphasizing in-situ technologies. Most important, MWLID`s success will be shared with other Federal, state, and local governments, and private companies that face the important task of waste site remediation. MWLID will demonstrate technologies at two existing landfills. Sandia National Laboratories` Chemical Waste Landfill received hazardous (chemical) waste from the Laboratory from 1962 to 1985, and the Mixed-Waste Landfill received hazardous and radioactive wastes (mixed wastes) over a twenty-nine year period (1959-1988) from various Sandia nuclear research programs. Both landfills are now closed. Originally, however, the sites were selected because of Albuquerque`s and climate and the thick layer of alluvial deposits that overlay groundwater approximately 480 feet below the landfills. This thick layer of ``dry`` soils, gravel, and clays promised to be a natural barrier between the landfills and groundwater.

  13. Appointment in Sonzay: Landfill gas fueled vehicles

    SciTech Connect

    Balbo, M.E.

    1997-05-01

    The SITA Group (Paris, France) an international waste management company, wanted to research and develop a means to economically and environmentally reuse the inherent value of its landfill gas. As the owner of more than 100 landfills in France alone--both hazardous and non-hazardous--SITA felt that it had a responsibility to research innovative gas treatment and/or reuse options, particularly as public scrutiny of landfill management practices was on the rise. In a successful pilot program initiated by SITA, landfill gas was reused as biofuel for vehicles in a way that was economically viable and environmentally sound.

  14. Turbines produce energy from L. A. landfill

    SciTech Connect

    Carry, C.W.; Stahl, J.F.; Maguin, S.R.; Friess, P.L.

    1984-06-01

    This article describes one of the Nation's most sophisticated resource recovery projects which began operating in February at the Puente Hills Landfill Methane Energy Station as part of the County Sanitation Districts of Los Angeles County. The project is currently generating 2.8 megawatts of power which would serve the electrical needs of approximately 5600 homes. Future plans for the landfill energy project include generating enough electricity for more than 50,000 homes. Unlike other methane recovery projects that use diesel or gasoline power reciprocating engines, the Puente Hills Landfill Methane Energy Station drives its electrical generators with gas turbines. This is a first for power generation at a landfill site.

  15. Laser recrystallization and inscription of compositional microstructures in crystalline SiGe-core fibres.

    PubMed

    Coucheron, David A; Fokine, Michael; Patil, Nilesh; Breiby, Dag Werner; Buset, Ole Tore; Healy, Noel; Peacock, Anna C; Hawkins, Thomas; Jones, Max; Ballato, John; Gibson, Ursula J

    2016-10-24

    Glass fibres with silicon cores have emerged as a versatile platform for all-optical processing, sensing and microscale optoelectronic devices. Using SiGe in the core extends the accessible wavelength range and potential optical functionality because the bandgap and optical properties can be tuned by changing the composition. However, silicon and germanium segregate unevenly during non-equilibrium solidification, presenting new fabrication challenges, and requiring detailed studies of the alloy crystallization dynamics in the fibre geometry. We report the fabrication of SiGe-core optical fibres, and the use of CO2 laser irradiation to heat the glass cladding and recrystallize the core, improving optical transmission. We observe the ramifications of the classic models of solidification at the microscale, and demonstrate suppression of constitutional undercooling at high solidification velocities. Tailoring the recrystallization conditions allows formation of long single crystals with uniform composition, as well as fabrication of compositional microstructures, such as gratings, within the fibre core.

  16. High power operation of cladding pumped holmium-doped silica fibre lasers.

    PubMed

    Hemming, Alexander; Bennetts, Shayne; Simakov, Nikita; Davidson, Alan; Haub, John; Carter, Adrian

    2013-02-25

    We report the highest power operation of a resonantly cladding-pumped, holmium-doped silica fibre laser. The cladding pumped all-glass fibre utilises a fluorine doped glass layer to provide low loss cladding guidance of the 1.95 µm pump radiation. The operation of both single mode and large-mode area fibre lasers was demonstrated, with up to 140 W of output power achieved. A slope efficiency of 59% versus launched pump power was demonstrated. The free running emission was measured to be 2.12-2.15 µm demonstrating the potential of this architecture to address the long wavelength operation of silica based fibre lasers with high efficiency.

  17. Laser recrystallization and inscription of compositional microstructures in crystalline SiGe-core fibres

    NASA Astrophysics Data System (ADS)

    Coucheron, David A.; Fokine, Michael; Patil, Nilesh; Breiby, Dag Werner; Buset, Ole Tore; Healy, Noel; Peacock, Anna C.; Hawkins, Thomas; Jones, Max; Ballato, John; Gibson, Ursula J.

    2016-10-01

    Glass fibres with silicon cores have emerged as a versatile platform for all-optical processing, sensing and microscale optoelectronic devices. Using SiGe in the core extends the accessible wavelength range and potential optical functionality because the bandgap and optical properties can be tuned by changing the composition. However, silicon and germanium segregate unevenly during non-equilibrium solidification, presenting new fabrication challenges, and requiring detailed studies of the alloy crystallization dynamics in the fibre geometry. We report the fabrication of SiGe-core optical fibres, and the use of CO2 laser irradiation to heat the glass cladding and recrystallize the core, improving optical transmission. We observe the ramifications of the classic models of solidification at the microscale, and demonstrate suppression of constitutional undercooling at high solidification velocities. Tailoring the recrystallization conditions allows formation of long single crystals with uniform composition, as well as fabrication of compositional microstructures, such as gratings, within the fibre core.

  18. Laser recrystallization and inscription of compositional microstructures in crystalline SiGe-core fibres

    PubMed Central

    Coucheron, David A.; Fokine, Michael; Patil, Nilesh; Breiby, Dag Werner; Buset, Ole Tore; Healy, Noel; Peacock, Anna C.; Hawkins, Thomas; Jones, Max; Ballato, John; Gibson, Ursula J.

    2016-01-01

    Glass fibres with silicon cores have emerged as a versatile platform for all-optical processing, sensing and microscale optoelectronic devices. Using SiGe in the core extends the accessible wavelength range and potential optical functionality because the bandgap and optical properties can be tuned by changing the composition. However, silicon and germanium segregate unevenly during non-equilibrium solidification, presenting new fabrication challenges, and requiring detailed studies of the alloy crystallization dynamics in the fibre geometry. We report the fabrication of SiGe-core optical fibres, and the use of CO2 laser irradiation to heat the glass cladding and recrystallize the core, improving optical transmission. We observe the ramifications of the classic models of solidification at the microscale, and demonstrate suppression of constitutional undercooling at high solidification velocities. Tailoring the recrystallization conditions allows formation of long single crystals with uniform composition, as well as fabrication of compositional microstructures, such as gratings, within the fibre core. PMID:27775066

  19. Humidity insensitive step-index polymer optical fibre Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Woyessa, G.; Fasano, A.; Stefani, A.; Markos, C.; Nielsen, K.; Rasmussen, H. K.; Bang, O.

    2015-09-01

    We have fabricated and characterised a humidity insensitive step index(SI) polymer optical fibre(POF) Bragg grating sensors. The fibre was made based on the injection molding technique, which is an efficient method for fast, flexible and cost effective preparation of the fibre preform. The fabricated SIPOF has a core made from TOPAS with a glass transition temperature of 134°C and a cladding from ZEONEX with a glass transition temperature of 138°C. The main advantages of the proposed SIPOF are the low water absorption and good chemical resistance compared to the conventional poly-methyl-methacrylate (PMMA) based SIPOFs. The fibre has a minimum loss of ~6dB/m at 770nm.

  20. Reversible changes in the reflectivity of different types of fibre Bragg gratings

    SciTech Connect

    Gnusin, P I; Vasil'ev, Sergei A; Medvedkov, O I; Dianov, Evgenii M

    2010-12-09

    We have studied strain- and temperature-induced reversible changes in the reflectivity of different types of fibre Bragg gratings. The results demonstrate that the strain sensitivity of the reflectivity of type I and IIa Bragg gratings is mainly due to the photoinduced reduction in the elasto-optic coefficient p{sub 12} of the core glass and that its temperature sensitivity results from the increase in the thermo-optic coefficient of the glass. UV exposure of fibres loaded with molecular hydrogen has an insignificant effect on these material coefficients. We also analyse the effects of UV fluence and germanium concentration in the fibre core on the reversible changes in the reflectivity of the grating. (optical fibres)

  1. Indirect aesthetic adhesive restoration with fibre-reinforced composite resin.

    PubMed

    Corona, S A M; Garcia, P P N S; Palma-Dibb, R G; Chimello, D T

    2004-10-01

    This paper describes the restoration of an endodontically treated upper first molar with a fibre-reinforced onlay indirect composite resin restoration. The clinical and radiographic examination confirmed that the tooth had suffered considerable loss of structure. Therefore, an indirect restoration was indicated. First, a core was built with resin-modified glass ionomer cement, followed by onlay preparation, mechanical/chemical gingival retraction and impression with addition-cured silicone. After the laboratory phase, the onlay was tried in, followed by adhesive bonding and occlusal adjustment. It can be concluded that fibre-reinforced aesthetic indirect composite resin restoration represented, in the present clinical case, an aesthetic and conservative treatment option. However, the use of fibres should be more extensively studied to verify the real improvement in physical and mechanical properties.

  2. Two-dimensional optical splitters with polymer optical fibre arrays

    NASA Astrophysics Data System (ADS)

    Wen, Fung Jacky; Sheun Chung, Po

    2007-07-01

    A novel approach for optical beam distribution into two-dimensional (2D) fibre arrays using 2D Dammann gratings is investigated. We report for the first time experimental results of a 2D optical power distribution into 2 × 2 polymer optical fibre arrays using a Dammann grating. This paper focuses on the design and fabrication of the diffractive optical element (DOE) along with investigating the coupling performance of the system. This grating may be applicable to a fibre to the home (FTTH) network as it can support sufficient channels with good output uniformity together with low polarization-dependent loss (PDL). Using an appropriate optimization algorithm, the optimum profile for the Dammann gratings can be calculated. The gratings are then fabricated on indium-doped tin oxide (ITO) glass using electron-beam lithography. This method shows that it can achieve low PDL and good uniformity together with acceptable insertion loss.

  3. Fibre reinforced CMC with polymer/filler derived matrix

    SciTech Connect

    Suttor, D.; Erny, T.; Greil, P.

    1995-09-01

    A ceramic matrix for carbon fibre reinforced ceramic matrix composites (CMC) has been developed from polysiloxane/boron mixtures. Complex geometries can be realized by using processing technologies of fibre reinforced polymer composites. Upon pyrolysis the polymer/filler mixture is converted into a ceramic matrix consisting of SiC, B{sub 4}C, BN and a Si-O-C-(N) glass, without reacting with the carbon fibre. Due to the large volume increase of the reactive boron filler upon nitridation (+142 vol%) no multiple reinfiltration of the structure is necessary in order to achieve a dense matrix. Thermodynamic modelling of the pyrolysis is a useful tool to estimate the qualitative and quantitative phase composition as a function of polymer, filler and gas atmospheres.

  4. Metal clad active fibres for power scaling and thermal management at kW power levels.

    PubMed

    Daniel, Jae M O; Simakov, Nikita; Hemming, Alexander; Clarkson, W Andrew; Haub, John

    2016-08-08

    We present a new approach to high power fibre laser design, consisting of a polymer-free all-glass optical fibre waveguide directly overclad with a high thermal conductivity metal coating. This metal clad active fibre allows a significant reduction in thermal resistance between the active fibre and the laser heat-sink as well as a significant increase in the operating temperature range. In this paper we show the results of a detailed thermal analysis of both polymer and metal coated active fibres under thermal loads typical of kW fibre laser systems. Through several different experiments we present the first demonstration of a cladding pumped aluminium-coated fibre laser and the first demonstration of efficient operation of a cladding-pumped fibre laser at temperatures of greater than 400 °C. Finally, we highlight the versatility of this approach through operation of a passively (radiatively) cooled ytterbium fibre laser head at an output power of 405 W in a compact and ultralight package weighing less than 100 g.

  5. Influence of dose history on thermoluminescence response of Ge-doped silica optical fibre dosimeters

    NASA Astrophysics Data System (ADS)

    Moradi, F.; Mahdiraji, G. A.; Dermosesian, E.; Khandaker, M. U.; Ung, N. M.; Mahamd Adikan, F. R.; Amin, Y. M.

    2017-05-01

    Nowadays, silica based optical fibres show enough potential to be used as TL dosimeters in different applications. Reuse of optical fibre as a practical dosimeter demands to complete removal of accumulated doses via previous irradiations. This work investigates the existence and/or effect of remnant doses in fibre dosimeter from the previous irradiations, and proposes a method to control this artifact. A single mode Ge-doped optical fibre is used as TL radiation sensor, while a well calibrated Gammacell with 60Co source is used for irradiations. The effect of irradiation history on the TL response of optical fibres is surveyed extensively for doses ranged from 1 to 1000 Gy. The results show that the absorbed dose history in a fibre affects its response in the next irradiation cycles. It is shown that a dose history of around 100 Gy can increase the response of optical fibre by a factor of 1.72. The effect of annealing at higher temperatures on stabilizing the fibre response is also examined and results revealed that another alteration in the structure of trapping states occurs in glass medium which can change the sensitivity of fibres. Preservation of the sensitivity during successive irradiation cycles can be achieved by a proper annealing procedure accompanied by a pre-dose treatment.

  6. Optical cochlear implant: evaluation of insertion forces of optical fibres in a cochlear model and of traumata in human temporal bones.

    PubMed

    Balster, Sven; Wenzel, Gentiana I; Warnecke, Athanasia; Steffens, Melanie; Rettenmaier, Alexander; Zhang, Kaiyin; Lenarz, Thomas; Reuter, Guenter

    2014-02-01

    Optical stimulation for hearing restoration is developing as an alternative therapy to electrical stimulation. For a more frequency-specific activation of the auditory system, light-guiding fibres need to be inserted into the coiled cochlea. To enable insertion with minimal trauma, glass fibres embedded in silicone were used as models. Thus, glass fibres of varying core/cladding diameter with and without silicon coating (single as well as in bundles) were inserted into a human scala tympani (ST) model. Insertion cochlear model force measurements were performed, and the thinner glass fibres that showed low insertion forces in the model were inserted into cadaveric human temporal bones. Silicone-coated glass fibres with different core/cladding diameters and bundle sizes could be inserted up to a maximum depth of 20 mm. Fibres with a core/cladding diameter of 50/55 μm break during insertion deeper than 7-15 mm into the ST model, whereas thinner fibres (20/25 μm) could be inserted in the model without breakage and in human temporal bones without causing trauma to the inner ear structures. The insertion forces of silicone-coated glass fibres are comparable to those measured with conventional cochlear implant (CI) electrodes. As demonstrated in human temporal bones, a minimal traumatic implantation of an optical CI may be considered feasible.

  7. Glass sealing

    SciTech Connect

    Brow, R.K.; Kovacic, L.; Chambers, R.S.

    1996-04-01

    Hernetic glass sealing technologies developed for weapons component applications can be utilized for the design and manufacture of fuel cells. Design and processing of of a seal are optimized through an integrated approach based on glass composition research, finite element analysis, and sealing process definition. Glass sealing procedures are selected to accommodate the limits imposed by glass composition and predicted calculations.

  8. High-energy pulsed fibre laser based on a two-fibre assembly

    SciTech Connect

    Kobtsev, Sergey M; Kukarin, S V; Fedotov, Yu S

    2009-05-31

    We demonstrate for the first time a relatively simple fibre laser system with a passively Q-switched master oscillator and a polarised output pulse energy of up to 110 {mu}J at 1080 nm. The system is pumped by a single 12-W multimode cw source at 980 nm. Depending on the pump power, the pulse duration varies from 280 ns to 1.8 {mu}s and the pulse repetition rate, from 45 to 140 kHz. The maximum average output power is 5 W. The system has been tested for its performance in metal and glass processing. (lasers and amplifiers)

  9. Image transport through a disordered optical fibre mediated by transverse Anderson localization.

    PubMed

    Karbasi, Salman; Frazier, Ryan J; Koch, Karl W; Hawkins, Thomas; Ballato, John; Mafi, Arash

    2014-02-25

    Transverse Anderson localization of light allows localized optical-beam-transport through a transversely disordered and longitudinally invariant medium. Its successful implementation in disordered optical fibres recently resulted in the propagation of localized beams of radii comparable to that of conventional optical fibres. Here we demonstrate optical image transport using transverse Anderson localization of light. The image transport quality obtained in the polymer disordered optical fibre is comparable to or better than some of the best commercially available multicore image fibres with less pixelation and higher contrast. It is argued that considerable improvement in image transport quality can be obtained in a disordered fibre made from a glass matrix with near wavelength-size randomly distributed air-holes with an air-hole fill-fraction of 50%. Our results open the way to device-level implementation of the transverse Anderson localization of light with potential applications in biological and medical imaging.

  10. Assessing the market opportunities of landfill mining.

    PubMed

    van der Zee, D J; Achterkamp, M C; de Visser, B J

    2004-01-01

    Long-term estimates make clear that the amount of solid waste to be processed at landfills in the Netherlands will sharply decline in coming years. Major reasons can be found in the availability of improved technologies for waste recycling and government regulations aiming at waste reduction. Consequently, market size for companies operating landfills shrinks. Among the companies facing the problem is the Dutch company Essent. Given the expected market conditions, it looks for alternative business opportunities. Landfill mining, i.e., the recycling of existing landfills, is considered one of them. Proceeds of landfill mining are related to, for example, recycled materials available for re-use, regained land, and possibilities for a more efficient operation of a landfill. The market for landfill mining is of a considerable size--there are about 3800 landfills located in the Netherlands. Given market size the company faces the dilemma of how to explore this market, i.e., select the most profitable landfills in a fast and efficient way. No existing methods or tools could be found to do so. Therefore, to answer to the problem posed, we propose a step-wise research method for market exploration. The basic idea behind the method is to provide an adequate, cost-saving and timely answer by relying on a series of quick scans. Relevant aspects of a mining project concern the proceeds of regained land and recyclables, the costs of the mining operation and the associated business and environmental risks. The method has been tested for its practical use in a pilot study. The pilot study addressed 147 landfills located in the Dutch Province of Noord-Brabant. The study made clear how method application resulted in the selection of a limited number of high potential landfills in a few weeks, involving minimal research costs.

  11. Heat management strategies for MSW landfills.

    PubMed

    Yeşiller, Nazli; Hanson, James L; Kopp, Kevin B; Yee, Emma H

    2016-10-01

    Heat is a primary byproduct of landfilling of municipal solid waste. Long-term elevated temperatures have been reported for MSW landfills under different operational conditions and climatic regions around the world. A conceptual framework is presented for management of the heat generated in MSW landfills. Three main strategies are outlined: extraction, regulation, and supplementation. Heat extraction allows for beneficial use of the excess landfill heat as an alternative energy source. Two approaches are provided for the extraction strategy: extracting all of the excess heat above baseline equilibrium conditions in a landfill and extracting only a part of the excess heat above equilibrium conditions to obtain target optimum waste temperatures for maximum gas generation. Heat regulation allows for controlling the waste temperatures to achieve uniform distribution at target levels at a landfill facility. Two approaches are provided for the regulation strategy: redistributing the excess heat across a landfill to obtain uniform target optimum waste temperatures for maximum gas generation and redistributing the excess heat across a landfill to obtain specific target temperatures. Heat supplementation allows for controlling heat generation using external thermal energy sources to achieve target waste temperatures. Two approaches are provided for the supplementation strategy: adding heat to the waste mass using an external energy source to increase waste temperatures and cooling the waste mass using an external energy source to decrease waste temperatures. For all strategies, available landfill heat energy is determined based on the difference between the waste temperatures and the target temperatures. Example analyses using data from landfill facilities with relatively low and high heat generation indicated thermal energy in the range of -48.4 to 72.4MJ/m(3) available for heat management. Further modeling and experimental analyses are needed to verify the effectiveness

  12. Hanford Site Solid Waste Landfill permit application

    SciTech Connect

    Not Available

    1991-01-01

    Daily activities at the Hanford Site generate sanitary solid waste (nonhazardous and nonradioactive) that is transported to and permanently disposed of at the Hanford Site Solid Waste Landfill. This permit application describes the manner in which the solid Waste Landfill will be operated under Washington State Department of Ecology Minimum Functional Standards for Solid Waste Handling, Washington Administrative Code 173-304. The solid Waste Landfill is owned by the US Department of Energy -- Richland Operations Office and is used for disposal of solid waste generated at the US Department of Energy Hanford Site. The jurisdictional health department's permit application form for the Solid Waste Landfill is provided in Chapter 1.0. Chapter 2.0 provides a description of the Hanford Site and the Solid Waste Landfill and reviews applicable locational, general facility, and landfilling standards. Chapter 3.0 discusses the characteristics and quantity of the waste disposed of in the Solid Waste Landfill. Chapter 4.0 reviews the regional and site geology and hydrology and the groundwater and vadose zone quality beneath the landfill. Chapters 5.0, 6.0, and 7.0 contain the plan of operation, closure plan, and postclosure plan, respectively. The plan of operation describes the routine operation and maintenance of the Solid Waste Landfill, the environmental monitoring program, and the safety and emergency plans. Chapter 5.0 also addresses the operational cover, environmental controls, personnel requirements, inspections, recordkeeping, reporting, and site security. The postclosure plan describes requirements for final cover maintenance and environmental monitoring equipment following final closure. Chapter 8.0 discusses the integration of closure and postclosure activities between the Solid Waste Landfill and adjacent Nonradioactive Dangerous Waste Landfill. 76 refs., 48 figs, 15 tabs.

  13. Fate and Transport of Landfill Contaminants, Naval Amphibious Base Little Creek, Virginia

    DTIC Science & Technology

    1993-12-01

    similar to a high strength wastewater. Conversion of biodegradable organic matter to gases ( CO2 and CH4 ), water and soluble organics also adds to the...quality with respect to glass and its high density provide the basis for its use in temperature and pressure measuring instruments. Low electrical...APPENDIX B HYDROLOGIC EVALUATION OF LANDFILL PERFORMANCE (HELP) PROGRAM OUTPUT ................................. 117 APPENDIX C EXAMPLE OUTPUT FROM

  14. Emergency landfill gas control at the Milwaukee County Landfill

    SciTech Connect

    Michels, M.S.; Boone, D.A.

    1996-11-01

    In October 1994, up to 55 percent methane concentrations by volume were found below 76th Street in Franklin, Wisconsin. Numerous utilities exist below 76th Street which service homes located only 100 feet east. The Milwaukee County Landfill, located immediately west of 76th Street, was the source of methane gas. With winter weather conditions approaching, Milwaukee County was concerned that landfill gas (LFG) could migrate along utilities or in sandy soil and enter basements of adjacent homes. The County declared an emergency to immediately release funds and authorized a design/build contract to remedy the gas migration. CDM Engineers and Constructors, Inc. was selected for the project. The Milwaukee County Department of Public Works, Environmental Services Division led the project team. Numerous activities occurred simultaneously, including: (1) Public Relations, (2) Notification to Wisconsin DNR, (3) Design and Permitting, (4) Ordering the Flare, (5) Installing Methane Detectors in 29 Basements. Public relations included public forums with local residences, monthly newsletters, meetings with the ski hill operator, television interviews, local newspaper interviews, briefing the County Alderman and City of Franklin officials. Cooperation from Wisconsin DNR provided a 10-day turnaround for approval of the design. A perimeter active gas collection and flare system was employed to mitigate LFG. The system included eight gas extraction wells drilled to the base of the landfill and one horizontal trench (approximately 40 feet long). Extraction wells and trench were connected together with a buried 6-inch HDPE header pipe. Condensate is collected in a 550-gallon double-walled steel tank.

  15. Characterization of landfill gas composition at the Fresh Kills municipal solid-waste landfill

    SciTech Connect

    Eklund, B.; Anderson, E.P.; Walker, B.L.; Burrows, D.B.

    1998-08-01

    The most common disposal method in the US for municipal solid waste (MSW) is burial in landfills. Until recently, air emissions from these landfills were not regulated. Under the New Source Performance Standards and Emission Guidelines for MSW landfills, MSW operators are required to determine the nonmethane organic gas generation rate of their landfill through modeling and/or measurements. This paper summarizes speciated nonmethane organic compound (NMOC) measurement data collected during an intensive, short-term field program. Over 250 separate landfill gas samples were collected from emission sources at the Fresh Kills landfill in New York City and analyzed for approximately 150 different analytes. The average total NMOC value for the landfill was 438 ppmv (as hexane) versus the regulatory default value of 4,000 ppmv (as hexane). Over 70 individual volatile organic compounds (VOCs) were detected and quantified in the landfill gas samples. The typical gas composition for this landfill was determined as well as estimates of the spatial, temporal, and measurement variability in the gas composition. The data for NMOC show that the gas composition within the landfill is equivalent to the composition of the gas exiting the landfill through passive vents and through the soil cover.

  16. Luminescence and photoinduced absorption in ytterbium-doped optical fibres

    SciTech Connect

    Rybaltovsky, A A; Aleshkina, S S; Likhachev, M E; Bubnov, M M; Umnikov, A A; Yashkov, M V; Gur'yanov, Aleksei N; Dianov, Evgenii M

    2011-12-31

    Photochemical reactions induced in the glass network of an ytterbium-doped fibre core by IR laser pumping and UV irradiation have been investigated by analysing absorption and luminescence spectra. We have performed comparative studies of the photoinduced absorption and luminescence spectra of fibre preforms differing in core glass composition: Al{sub 2}O{sub 3} : SiO{sub 2}, Al{sub 2}O{sub 3} : Yb{sub 2}O{sub 3} : SiO{sub 2}, and P{sub 2}O{sub 5} : Yb{sub 2}O{sub 3} : SiO{sub 2}. The UV absorption spectra of unirradiated preform core samples show strong bands peaking at 5.1 and 6.5 eV, whose excitation plays a key role in photoinduced colour centre generation in the glass network. 'Direct' UV excitation of the 5.1- and 6.5-eV absorption bands at 244 and 193 nm leads to the reduction of some of the Yb{sup 3+} ions to Yb{sup 2+}. The photodarkening of ytterbium-doped fibres by IR pumping is shown to result from oxygen hole centre generation. A phenomenological model is proposed for the IR-pumping-induced photodarkening of ytterbium-doped fibres. The model predicts that colour centre generation in the core glass network and the associated absorption in the visible range result from a cooperative effect involving simultaneous excitation of a cluster composed of several closely spaced Yb{sup 3+} ions.

  17. Effect of the active-ion concentration on the lasing dynamics of holmium fibre lasers

    SciTech Connect

    Kurkov, Andrei S; Sholokhov, E M; Marakulin, A V; Minashina, L A

    2010-12-09

    The lasing dynamics of fibre lasers with a core based on quartz glass doped with holmium ions to concentrations in the range of 10{sup 19}-10{sup 20} cm{sup -3} is investigated. It is shown that fibre lasers with a high concentration of active holmium ions generate pulses, but a decrease in the holmium concentration changes the lasing from pulsed to cw regime. At the same time, a decrease in the active-ion concentration and the corresponding increase in the fibre length in the cavity reduce the lasing efficiency. (lasers)

  18. Simulation of tensile strength of anisotropic fibre-reinforced composites at low temperature

    NASA Astrophysics Data System (ADS)

    Abdelmohsen, H. H.

    This article presents a simulation scheme to predict the effect of fibre anisotropy on composite tensile failure strength at room and low temperatures. The simulation model combines the shear lag equation with the chain of bundles probability model to describe the composite failure behaviour. The effect of fibre anisotropy on thermal stresses developed in composite constituents due to cooling to low temperatures is considered. The failure strength of composites composed of fibres with different degrees of anisotropy is obtained and comparisons are made with experiments. Simulated results for E-glass-, graphite- and Kevlar-epoxy type composites showed close agreement with the experiments.

  19. Second-order Bragg gratings in single-mode chalcogenide fibres

    SciTech Connect

    Bernier, M; Asatryan, K E; Vallee, R; Galstian, T M; Vasil'ev, Sergei A; Medvedkov, O I; Plotnichenko, V G; Gnusin, P I; Dianov, Evgenii M

    2011-05-31

    Bragg gratings with a second-order resonance wavelength in the near-IR spectral region have been inscribed into single-mode chalcogenide (As{sub 2}S{sub 3}) glass fibre by a He - Ne laser beam using a configuration typical of Bragg grating fabrication in germanosilicate fibre, with the use of a phase mask that ensures effective diffraction of the writing light into the +1 and -1 orders. The spectra of the inscribed gratings show no resonances due to cladding mode excitation because the cladding material is photosensitive. (fibre optics)

  20. FIBER OPTICS: Fibre optics: Forty years later

    NASA Astrophysics Data System (ADS)

    Dianov, Evgenii M.

    2010-01-01

    This paper presents a brief overview of the state of the art in fibre optics and its main applications: optical fibre communications, fibre lasers and fibre sensors for various physical property measurements. The future of fibre optics and the status of this important area of the modern technology in Russia are discussed.

  1. Small fibre neuropathy.

    PubMed

    Lauria, Giuseppe; Merkies, Ingemar S J; Faber, Catharina G

    2012-10-01

    This review summarizes the most recent advances in classification, diagnostic assessment, and treatment of small fibre neuropathy (SFN). Clinically based diagnostic criteria for SFN have been proposed and reliably supported by the recent availability of age-adjusted and sex-adjusted normative values for intraepidermal nerve fibre density. Apart from skin biopsy, corneal confocal microscopy and nociceptive evoked potentials have been implemented to investigate SFN of different causes, and correlated with skin biopsy findings, especially in diabetic patients. The association between SFN and several metabolic and immune-mediated systemic diseases, and drugs toxic to this subset of peripheral nerve fibres has been reported. An exciting advance has been the identification of gain-of-function mutations in the SCN9A gene encoding for Nav1.7 sodium channel in patients with SFN, leading to the definition of a new genetic channelopathy. SFN represents a distinct condition encountered in patients with different acquired and genetic disorders. The recent improved definition of clinical and skin biopsy criteria allows clinicians to reliably meet the diagnosis, identify the underlying cause, and prescribe appropriate treatments. This meaningful approach permits the correct management of patients in clinical practice and the design of symptomatic and disease-modifying clinical trials.

  2. Distributed ultrafast fibre laser

    PubMed Central

    Liu, Xueming; Cui, Yudong; Han, Dongdong; Yao, Xiankun; Sun, Zhipei

    2015-01-01

    A traditional ultrafast fibre laser has a constant cavity length that is independent of the pulse wavelength. The investigation of distributed ultrafast (DUF) lasers is conceptually and technically challenging and of great interest because the laser cavity length and fundamental cavity frequency are changeable based on the wavelength. Here, we propose and demonstrate a DUF fibre laser based on a linearly chirped fibre Bragg grating, where the total cavity length is linearly changeable as a function of the pulse wavelength. The spectral sidebands in DUF lasers are enhanced greatly, including the continuous-wave (CW) and pulse components. We observe that all sidebands of the pulse experience the same round-trip time although they have different round-trip distances and refractive indices. The pulse-shaping of the DUF laser is dominated by the dissipative processes in addition to the phase modulations, which makes our ultrafast laser simple and stable. This laser provides a simple, stable, low-cost, ultrafast-pulsed source with controllable and changeable cavity frequency. PMID:25765454

  3. Fibre-optical microendoscopy.

    PubMed

    Gu, M; Bao, H; Kang, H

    2014-04-01

    Microendoscopy has been an essential tool in exploring micro/nano mechanisms in vivo due to high-quality imaging performance, compact size and flexible movement. The investigations into optical fibres, micro-scanners and miniature lens have boosted efficiencies of remote light delivery to sample site and signal collection. Given the light interaction with materials in the fluorescence imaging regime, this paper reviews two classes of compact microendoscopy based on a single fibre: linear optical microendoscopy and nonlinear optical microendoscopy. Due to the fact that fluorescence occurs only in the focal volume, nonlinear optical microendoscopy can provide stronger optical sectioning ability than linear optical microendoscopy, and is a good candidate for deep tissue imaging. Moreover, one-photon excited fluorescence microendoscopy as the linear optical microendoscopy suffers from severe photobleaching owing to the linear dependence of photobleaching rate on excitation laser power. On the contrary, nonlinear optical microendoscopy, including two-photon excited fluorescence microendoscopy and second harmonic generation microendoscopy, has the capability to minimize or avoid the photobleaching effect at a high excitation power and generate high image contrast. The combination of various nonlinear signals gained by the nonlinear optical microendoscopy provides a comprehensive insight into biophenomena in internal organs. Fibre-optical microendoscopy overcomes physical limitations of traditional microscopy and opens up a new path to achieve early cancer diagnosis and microsurgery in a minimally invasive and localized manner.

  4. Binding of environmental carcinogens to asbestos and mineral fibres.

    PubMed Central

    Harvey, G; Pagé, M; Dumas, L

    1984-01-01

    A rapid method has been developed for measuring the binding capacity of asbestos and other mineral fibres for environmental carcinogens. Benzo(alpha)pyrene (B(alpha)P), nitrosonornicotine (NNN), and N-acetyl-2-aminofluorene (NAAF) were assayed in the presence of Canadian grade 4T30 chrysotile, chrysotile A, amosite, crocidolite, glass microfibres, glasswool, attapulgite, and titanium dioxide. Chrysotile binds significantly more carcinogens than the other mineral fibres. This binding assay is reproducible with coefficients of variation of less than 8% and 6% respectively for inter and intra assay. The influence of pH was also studied, and there is good correlation between the carcinogen binding and the charge of the tested mineral fibres. The in vitro cytotoxicity on macrophage like cell line P388D1 and the haemolytic activity of various mineral fibres were also measured; a good correlation was found between the binding capacity and the cytotoxicity of tested mineral fibres on P388D1 cells. These results give some explanations for the reported synergism between exposure to asbestos and the smoking habits of workers. PMID:6331497

  5. LANDFILL GAS PRETREATMENT FOR FUEL CELL APPLICATIONS

    EPA Science Inventory

    The paper discusses the U.S. EPA's program, underway at International Fuel Cells Corporation, to demonstrate landfill methane control and the fuel cell energy recovery concept. In this program, two critical issues are being addressed: (1) a landfill gas cleanup method that would ...

  6. Quantifying capital goods for waste landfilling.

    PubMed

    Brogaard, Line K; Stentsøe, Steen; Willumsen, Hans Christian; Christensen, Thomas H

    2013-06-01

    Materials and energy used for construction of a hill-type landfill of 4 million m(3) were quantified in detail. The landfill is engineered with a liner and leachate collections system, as well as a gas collection and control system. Gravel and clay were the most common materials used, amounting to approximately 260 kg per tonne of waste landfilled. The environmental burdens from the extraction and manufacturing of the materials used in the landfill, as well as from the construction of the landfill, were modelled as potential environmental impacts. For example, the potential impact on global warming was 2.5 kg carbon dioxide (CO2) equivalents or 0.32 milli person equivalents per tonne of waste. The potential impacts from the use of materials and construction of the landfill are low-to-insignificant compared with data reported in the literature on impact potentials of landfills in operation. The construction of the landfill is only a significant contributor to the impact of resource depletion owing to the high use of gravel and steel.

  7. Municipal waste landfill permitting in Pennsylvania

    SciTech Connect

    Mentzer, G.F.

    1996-11-01

    The Commonwealth of Pennsylvania has 50 permitted municipal waste landfills (MWL) with calculated capacities ranging from 0.5 to 25.3 million tons. The most common size for our landfills is in the range of 3 to 5 million tons, with three landfills exceeding the 20+ million ton capacity. Future expansion projects will increase a few landfills to in excess of 35+ million tons. Exact VOC emission numbers are not available since not all landfills have or are required to report their emissions to the Pennsylvania air emissions database. However, estimates from several of our larger facilities indicates the uncontrolled VOC emissions are in the range of 250 to 350 TPY with a possible high of 580 TPY. Although the numbers are not exact, it does point out the fact that landfills are a major source of VOC emissions. With the advent of the Environmental Protection Agency`s (EPA) proposed New Source Performance Standards (Subpart WWW) and emissions guidance (Subpart Cc), the EPA declared that the MWL are a source of air pollution. Following the release of these proposed regulations, the Department of Environmental Protection, Bureau of Air Quality began in mid 1994 the task of permitting landfills. Through the use of customized forms G(A) and G(B), the Department made in 1995 its first attempt to identify and quantify emissions from its landfills. The process of quantifying and verifying emission estimates is still on going. To date, the Department is in various stages of permitting eight MWL.

  8. Field Water Balance of Landfill Final Covers

    EPA Science Inventory

    Landfill covers are critical to waste containment, yet field performance of specific cover designs has not been well documented and seldom been compared in side-by-side testing. A study was conducted to assess the ability of landfill final covers to control percolation into unde...

  9. LANDFILL GAS PRETREATMENT FOR FUEL CELL APPLICATIONS

    EPA Science Inventory

    The paper discusses the U.S. EPA's program, underway at International Fuel Cells Corporation, to demonstrate landfill methane control and the fuel cell energy recovery concept. In this program, two critical issues are being addressed: (1) a landfill gas cleanup method that would ...

  10. MONITORING APPROACHES FOR BIOREACTOR LANDFILLS - Report

    EPA Science Inventory

    Experimental bioreactor landfill operations at operating Municipal Solid Waste (MSW) landfills can be approved under the research development and demonstration (RD&D) provisions of 30CFR 258.4. To provide a basis for consistent data collection for future decision-making in suppor...

  11. MONITORING APPROACHES FOR BIOREACTOR LANDFILLS - Report

    EPA Science Inventory

    Experimental bioreactor landfill operations at operating Municipal Solid Waste (MSW) landfills can be approved under the research development and demonstration (RD&D) provisions of 30CFR 258.4. To provide a basis for consistent data collection for future decision-making in suppor...

  12. Field Water Balance of Landfill Final Covers

    EPA Science Inventory

    Landfill covers are critical to waste containment, yet field performance of specific cover designs has not been well documented and seldom been compared in side-by-side testing. A study was conducted to assess the ability of landfill final covers to control percolation into unde...

  13. Properties of nanocomposite PP fibres

    NASA Astrophysics Data System (ADS)

    Smole, Majda S.; Stakne, Kristina; Svetec, Diana G.; Kleinschek, Karin S.; Ribitsch, Volker

    2005-06-01

    PP-based nanocomposite fibres were prepared by direct polymer melt intercalation. With the intention to determine the size and dispersion of nanoparticles in the polymer matrix, fibres were plasma etched and SEM observations were performed. The influence of nanofiller content and coupling agent on electrokinetic properties was studied. PP monofilament fibres exhibit hydrophobe character with negative zeta potential value. The zeta potential value of co-polymer PP fibre decreases with increasing PPAA content and the isoelectric point IEP of co-polymer samples shifts towards acid region. Addition of modified montmorillonite due to the particles electropositive character, affects the reduction of zeta potential value and a slight shift of IEP towards neutral region is observed. Nano-particles content influences electrokinetic fibres properties, i.e. ZP value is changed, however IE point is not significantly changed by different concentrations of nanofiller. In addition to, mechanical properties of nanocomposite fibres were determined.

  14. Degradability of Chlorinated Solvents in Landfill Environment

    NASA Astrophysics Data System (ADS)

    Wang, J. Y.; Litman, M.

    2002-12-01

    The use of landfills as an in situ remediation system represents a cost-effective alternative for groundwater remediation in the source area. This research was conducted to investigate the intrinsic bioattenuation capacity of the landfill ecosystem for chlorinated aliphatic hydrocarbons (CAHs). This research, using excavated refuse samples, studied how the reductive dechlorination of CAHs is linked to the decomposition of solid waste in landfills. Most research effort in groundwater remediation has focused on the contaminant plumes beneath and downgradient from landfills, while the source area remediation has received increasing attention. Bioreactor landfill and leachate recirculation projects have been planned and implemented by the USEPA and some states. However, the use of bioreactor landfill has primarily been considered only to expedite refuse decomposition. This research provides an understanding of the biological fate of CAHs in landfills, an understanding that can lead to the bioreactor landfill system designed to promote the degradation of pollutants right at the source. The research was conducted in two complementary systems: simulated landfill bioreactors and batch degradation experiment in serum bottles. Refuse samples were excavated from a municipal solid waste landfill located in Wayland, Massachusetts, USA. Bioreactors were designed and operated to facilitate refuse decomposition under landfilling conditions. For each reactor, leachate was collected and recirculated back to the reactor and gas was collected into a gas bag and the methane production rate was monitored. Target CAHs, tetrachloroethene (PCE) and trichloroethene (TCE), were added to selected reactors and maintained at about 20 uM each in leachate. The design is to study the effect of long-term exposure of refuse microorganisms to CAHs on the degradation potential of these chemicals in landfills. Changes of biochemical conditions in bioreactors, including leachate pH, leachate COD, and

  15. Venice Park landfill: Working with the community

    SciTech Connect

    McAdams, C.L.

    1993-09-01

    Venice Park landfill was one of the first sites to be permitted under Michigan's proposed Public Act 641. PA 641 essentially changed the rules and regulations for landfills from the simple design of digging a hole and filling it. It also upgraded standards to those that are more sophisticated, including liners, leachate collection systems, and gas extraction systems. In 1992, methane gas from the landfill was collected into wells drilled into the trash varying in depth from 30-50 feet in depth. A vacuum pulls the gas from the trash into the wells, then through a piping system. The landfill uses about 80-100 kilowatts in-house. The remainder of the gas is sold to Consumers Power Co. which uses landfill gas to supply power to homes.

  16. Methane landfill gas. an 80's reality

    SciTech Connect

    Not Available

    1980-08-01

    According to a recent American Gas Association report, enough methane could be extracted from America's city dumps during the 1980's to supply to 2.1 million homes annually. But to do so, federal and state policies limiting the size of dumps must be contended with. Recovery plants cost $10-$50 million. The economic breakeven point is a landfill that handles 300,000-500,000 tons/yr of refuse, based on a recovery rate of 3 million Btu of pipeline-quality gas from each ton of refuse. The economics of landfill gas recovery involve low transportation costs, since landfills are generally near urban areas where end users are located. Nationally, economic and indirect benefits would result in landfill gas having a value of over $10/million Btu to the U.S. Unfortunately, regulatory barriers exist despite a precedent of 13 active landfill methane recovery plants in operation at present in California, New Jersey, and New York.

  17. Analysis of landfills with historic airphotos

    NASA Technical Reports Server (NTRS)

    Erb, T. L.; Philipson, W. R.; Teng, W. L.; Liang, T.

    1981-01-01

    An investigation is conducted regarding the value of existing aerial photographs for waste management, including landfill monitoring. The value of historic aerial photographs for documenting landfill boundaries is shown in a graph in which the expansion of an active landfill is traced over a 40-year period. Historic aerial photographs can also be analyzed to obtain general or detailed land-use and land-cover information. In addition, the photographs provide information regarding other elements of the physical environment, including geology, soils, and surface and subsurface drainage. The value of historic photos is discussed, taking into account applications for inventory, assessing contamination/health hazards, planning corrective measures, planning waste collection and facilities, developing inactive landfills, and research concerning improved land-filling operations.

  18. Compressive failure of fibre composites

    NASA Astrophysics Data System (ADS)

    Budiansky, B.; Fleck, N. A.

    1993-01-01

    A REVIEW OF experimental data and elementary theoretical formulas for compressive failure of polymer matrix fibre composites indicates that the dominant failure mode is by plastic kinking. Initial local fibre misalignment plays a central role in the plastic kinking process. Theoretical analyses and numerical results for compressive kinking are presented, encompassing effects of strain-hardening, kink inclination, and applied shear stress. The assumption of rigid fibres is assessed critically, and the legitimacy of its use for polymer matrix composites is established.

  19. The dependence of the methylation of mercury on the landfill stabilization process and implications for the landfill management.

    PubMed

    Chai, Xiaoli; Hao, Yongxia; Li, Zhonggen; Zhu, Wei; Zhao, Wentao

    2015-01-01

    Mercury species and other chemical characteristics of the leachate from anaerobic and semi-aerobic landfills were analyzed to investigate the factors that control mercury methylation during the landfill stabilization process. At the early landfill stage, the total mercury (THg) and the monomethyl mercury (MMHg) released rapidly and significantly, the THg concentration of the semi-aerobic landfill leachate was obviously higher than that of the anaerobic landfill leachate, while compared with the semi-aerobic landfill, the MMHg concentration in the anaerobic landfill was higher. As the landfill time increased, both of THg and MMHg concentration decreased quickly, the THg concentration in the anaerobic landfill was much higher than that in semi-aerobic landfill, while the MMHg concentration in the anaerobic landfill was lower than that in the semi-aerobic landfill. Generally, the concentrations of dimethyl mercury (DMHg) in the anaerobic landfill leachate were slightly higher than in the semi-aerobic landfill leachate during the stabilization process. A significant positive correlation was found between the DMHg concentrations and the pH value in anaerobic landfill leachate, but this correlation was opposite in the semi-aerobic landfill. The oxidative-reductive potential (ORP) condition was found to be the controlling factor of the methylation process during the early stage. However, the chemical characteristics, especially the TOC concentration, appeared to be the dominant factor affecting the methylation process as the landfill time increased.

  20. Fibre constituents of some foods.

    PubMed

    Rani, B; Kawatra, A

    1994-06-01

    Some plant foods viz. bottlegourd, carrot, cauliflower, cabbage, green bengalgram, pea, apple, plum, guava, karonda, blackgram husk and lentil husk were analysed for their dietary fibre components. The total dietary fibre contents of these foods varied from 14.68 to 78.21 percent on dry matter basis. As compared to fruits and vegetables, the husks had higher amount of total dietary fibre. Cellulose represented as the major fibre constituent in most of the foods whereas, husks were observed to be good sources of hemicellulose. All foods were low in pectin and lignin contents except guava.

  1. A Study of Leachate Generated from Construction and Demolition Landfills,

    DTIC Science & Technology

    2007-11-02

    solid waste (MSW) landfills and hazardous waste landfills. Regulators felt that since C&D landfills did not accept large quantities of hazardous waste...Construction and demolition (C&D) waste landfills have largely been ignored because they have been viewed as innocuous in comparison to municipal

  2. Mining the Midden: A Facility for Dynamic Waste Harvesting at the Cedar Hills Regional Landfill

    NASA Astrophysics Data System (ADS)

    Allan, Aaron

    Mining the Midden intends to re-frame the sanitary landfill as a new typology of public land containing an embodied energy of cultural and material value. By reconnecting the public with the landfill and seriously exposing its layers of history and then digesting both mined and new waste within an industrial facility of materials recovery and plasma gasification technology waste-to-energy plant. The sequence of experience for a public visitor begins where the waste is transformed to energy and flows in the opposite direction of the trash through the facility and then into the active landfill mining operation which is the large site component of the project. The mine is flanked by the visitor path, which is suspended from the soldier piles of the excavation system and allows the visitor to interpret along the 1/3 mile path their personal connection to the waste stream and the consumption patterns which drive our waste. Interpretation results from multi-sensory experience of the open mine and its connection to the processing structure as one hovers above, through moments of seeing through structural glass lagging directly into the sectional cut of the landfill, and through cultural artifacts harvested by landfill archaeologists which are displayed in rhythm with the structure and lagging. The culmination of the prescribed path is a narrow cut which frames the view of Mt. Rainier in the distance and opens up a visual connection with the remaining majority of the landfill which have up to this point been blocked by the small mountain of trash which they just walked up and through. This thesis intends that by confronting people with the juxtapositions of 2 potentially destructive mounds or mountains, and how we as a culture value and protect land while we simultaneously dump our rubbish on other lands, this experience will make the visitor more conscious of ones personal contribution to our culture of disposable commodities.

  3. Leachates draining from controlled municipal solid waste landfill: Detailed geochemical characterization and toxicity tests.

    PubMed

    Mavakala, Bienvenu K; Le Faucheur, Séverine; Mulaji, Crispin K; Laffite, Amandine; Devarajan, Naresh; Biey, Emmanuel M; Giuliani, Gregory; Otamonga, Jean-Paul; Kabatusuila, Prosper; Mpiana, Pius T; Poté, John

    2016-09-01

    Management of municipal solid wastes in many countries consists of waste disposal into landfill without treatment or selective collection of solid waste fractions including plastics, paper, glass, metals, electronic waste, and organic fraction leading to the unsolved problem of contamination of numerous ecosystems such as air, soil, surface, and ground water. Knowledge of leachate composition is critical in risk assessment of long-term impact of landfills on human health and the environment as well as for prevention of negative outcomes. The research presented in this paper investigates the seasonal variation of draining leachate composition and resulting toxicity as well as the contamination status of soil/sediment from lagoon basins receiving leachates from landfill in Mpasa, a suburb of Kinshasa in the Democratic Republic of the Congo. Samples were collected during the dry and rainy seasons and analyzed for pH, electrical conductivity, dissolved oxygen, soluble ions, toxic metals, and were then subjected to toxicity tests. Results highlight the significant seasonal difference in leachate physicochemical composition. Affected soil/sediment showed higher values for toxic metals than leachates, indicating the possibility of using lagoon system for the purification of landfill leachates, especially for organic matter and heavy metal sedimentation. However, the ecotoxicity tests demonstrated that leachates are still a significant source of toxicity for terrestrial and benthic organisms. Therefore, landfill leachates should not be discarded into the environment (soil or surface water) without prior treatment. Interest in the use of macrophytes in lagoon system is growing and toxic metal retention in lagoon basin receiving systems needs to be fully investigated in the future. This study presents useful tools for evaluating landfill leachate quality and risk in lagoon systems which can be applied to similar environmental compartments. Copyright © 2016 Elsevier Ltd. All

  4. Integration of conductive reduced graphene oxide into microstructured optical fibres for optoelectronics applications

    PubMed Central

    Ruan, Yinlan; Ding, Liyun; Duan, Jingjing; Ebendorff-Heidepriem, Heike; Monro, Tanya M.

    2016-01-01

    Integration of conductive materials into optical fibres can largely expand functions of fibre devices including surface plasmon resonator/metamaterial, modulators/detectors, or biosensors. Some early attempts have been made to incorporate metals such as tin into fibres during the fibre drawing process. Due to the restricted range of materials that have compatible melting temperatures with that of silica glass, the methods to incorporate metals along the length of the fibres are very challenging. Moreover, metals are nontransparent with strong light absorption, which causes high fibre loss. This article demonstrates a novel but simple method for creating transparent conductive reduced graphene oxide film onto microstructured silica fibres for potential optoelectronic applications. The strongly confined evanescent field of the suspended core fibres with only 2 μW average power was creatively used to transform graphene oxide into reduced graphene oxide with negligible additional loss. Existence of reduced graphene oxide was confirmed by their characteristic Raman signals, shifting of their fluorescence peaks as well as largely decreased resistance of the bulk GO film after laser beam exposure. PMID:26899468

  5. Integration of conductive reduced graphene oxide into microstructured optical fibres for optoelectronics applications

    NASA Astrophysics Data System (ADS)

    Ruan, Yinlan; Ding, Liyun; Duan, Jingjing; Ebendorff-Heidepriem, Heike; Monro, Tanya M.

    2016-02-01

    Integration of conductive materials into optical fibres can largely expand functions of fibre devices including surface plasmon resonator/metamaterial, modulators/detectors, or biosensors. Some early attempts have been made to incorporate metals such as tin into fibres during the fibre drawing process. Due to the restricted range of materials that have compatible melting temperatures with that of silica glass, the methods to incorporate metals along the length of the fibres are very challenging. Moreover, metals are nontransparent with strong light absorption, which causes high fibre loss. This article demonstrates a novel but simple method for creating transparent conductive reduced graphene oxide film onto microstructured silica fibres for potential optoelectronic applications. The strongly confined evanescent field of the suspended core fibres with only 2 μW average power was creatively used to transform graphene oxide into reduced graphene oxide with negligible additional loss. Existence of reduced graphene oxide was confirmed by their characteristic Raman signals, shifting of their fluorescence peaks as well as largely decreased resistance of the bulk GO film after laser beam exposure.

  6. Integration of conductive reduced graphene oxide into microstructured optical fibres for optoelectronics applications.

    PubMed

    Ruan, Yinlan; Ding, Liyun; Duan, Jingjing; Ebendorff-Heidepriem, Heike; Monro, Tanya M

    2016-02-22

    Integration of conductive materials into optical fibres can largely expand functions of fibre devices including surface plasmon resonator/metamaterial, modulators/detectors, or biosensors. Some early attempts have been made to incorporate metals such as tin into fibres during the fibre drawing process. Due to the restricted range of materials that have compatible melting temperatures with that of silica glass, the methods to incorporate metals along the length of the fibres are very challenging. Moreover, metals are nontransparent with strong light absorption, which causes high fibre loss. This article demonstrates a novel but simple method for creating transparent conductive reduced graphene oxide film onto microstructured silica fibres for potential optoelectronic applications. The strongly confined evanescent field of the suspended core fibres with only 2 μW average power was creatively used to transform graphene oxide into reduced graphene oxide with negligible additional loss. Existence of reduced graphene oxide was confirmed by their characteristic Raman signals, shifting of their fluorescence peaks as well as largely decreased resistance of the bulk GO film after laser beam exposure.

  7. Utilization of natural zeolite and perlite as landfill liners for in situ leachate treatment in landfills.

    PubMed

    Ozel, Ummukulsum; Akdemir, Andaç; Ergun, Osman Nuri

    2012-05-01

    The potential long term environmental impacts of a landfill on groundwater quality depend on its liner material properties. In case synthetic liner materials are damaged during the construction or operation, many of the original chemical and biological constituents are removed by filtration and the adsorptive action of natural liner materials such as natural zeolite, perlite and bentonite minerals. Before leachate treatment, reduction of these constituents is important not only to leachate percolation, but also treatment cost and efficiency. In this study, the pollutant removal efficiency from the leachate was investigated for natural natural zeolite, expanded perlite and bentonite. Experimental studies was performed in boxes made of glass and with 1:10 sloping. Leachate quantity was determined and pH, electrical conductivity (EC), nitrate (NO(3)-N), ammonium-nitrogen (NH(4)-N), phosphate (PO(4)), chemical oxygen demand (COD) and organic matter in leachate samples were measured and the measurement was compared with control process (System 4). The results showed that natural zeolite was effective in removing NO(3), NH(4), PO(4), COD and organic matter with removal efficiencies of 91.20, 95.6, 95.5, 83.4 and 87.8%, respectively. Expanded perlite has high efficiency removing of NO(3), PO(4) and COD 83.2, 91.0 and 62.5%, respectively, but it was unsuccessful in reducing NH(4) (1.5%).

  8. Utilization of Natural Zeolite and Perlite as Landfill Liners for in Situ Leachate Treatment in Landfills

    PubMed Central

    Ozel, Ummukulsum; Akdemir, Andaç; Ergun, Osman Nuri

    2012-01-01

    The potential long term environmental impacts of a landfill on groundwater quality depend on its liner material properties. In case synthetic liner materials are damaged during the construction or operation, many of the original chemical and biological constituents are removed by filtration and the adsorptive action of natural liner materials such as natural zeolite, perlite and bentonite minerals. Before leachate treatment, reduction of these constituents is important not only to leachate percolation, but also treatment cost and efficiency. In this study, the pollutant removal efficiency from the leachate was investigated for natural natural zeolite, expanded perlite and bentonite. Experimental studies was performed in boxes made of glass and with 1:10 sloping. Leachate quantity was determined and pH, electrical conductivity (EC), nitrate (NO3-N), ammonium-nitrogen (NH4-N), phosphate (PO4), chemical oxygen demand (COD) and organic matter in leachate samples were measured and the measurement was compared with control process (System 4). The results showed that natural zeolite was effective in removing NO3, NH4, PO4, COD and organic matter with removal efficiencies of 91.20, 95.6, 95.5, 83.4 and 87.8%, respectively. Expanded perlite has high efficiency removing of NO3, PO4 and COD 83.2, 91.0 and 62.5%, respectively, but it was unsuccessful in reducing NH4 (1.5%). PMID:22754458

  9. Modified femtosecond laser inscription method for tailored grating sensors in encapsulated silica and low-loss polymer optical fibres

    NASA Astrophysics Data System (ADS)

    Kalli, Kyriacos; Lacraz, Amedee; Theodosiou, Andreas; Kofinas, Marios

    2016-05-01

    There is great interest in the development of flexible wavelength filters and optical fibre sensors, such as Bragg and superstructure gratings, grating arrays and chirped gratings in glass and polymer optical fibres. A major hurdle is the development of an inscription method that should offer flexibility and reliability and be generally applicable to all optical fibre types. With this in mind we have developed a novel femtosecond laser inscription method; plane-by-plane inscription, whereby a 3D-index change of controlled length across the fibre core, width along the fibre axis and depth is written into the optical fibre. We apply this method for the inscription of various grating types in coated silica and low- loss CYTOP polymer optical fibres. The plane-by-plane method allows for multiple and overlapping gratings in the fibre core. Moreover, we demonstrate that this novel fibre Bragg grating inscription technique can be used to modify and add versatility to an existing, encapsulated optical fibre pressure sensor. The femtosecond laser is operated in the green or the near infra-red, based on the material properties under laser modification.

  10. Recycling of aged refuse from a closed landfill.

    PubMed

    Zhao, Youcai; Song, Liyan; Huang, Renhua; Song, Lijie; Li, Xiong

    2007-04-01

    In this study, refuse excavated from a typical refuse landfill in Shanghai after 8-10 years of placement was characterized in terms of particle size, total nitrogen, total phosphorus, and biodegradable matter. The refuse contained a large and diverse population of micro-organisms with a high capacity for decomposing refractory organic matter present in some wastewaters, including leachate. It was found that the aged refuse was quite stable after about a decade of decomposition in the warm, humid climate of southern China. The fine fractions resembled and had the properties of black soil, a medium that is suitable for green construction, organic fertilizer, or as bioreactor media for biological treatment of organic wastewaters. Excavation of the aged refuse would make about 50% of the space available for fresh refuse. The plastics, glass, textiles, and cans can be readily mechanically separated and recycled after cleaning. It is estimated that at least 200 millions tonnes of such aged refuse are available in China alone, and at least 10 times that much is buried worldwide. Hence, the evaluation of mined landfill waste and consideration of its potential uses is of great significance.

  11. Applications for carbon fibre recovered from composites

    NASA Astrophysics Data System (ADS)

    Pickering; Liu, Z.; Turner, TA; Wong, KH

    2016-07-01

    Commercial operations to recover carbon fibre from waste composites are now developing and as more recovered fibre becomes available new applications for recovered fibre are required. Opportunities to use recovered carbon fibre as a structural reinforcement are considered involving the use of wet lay processes to produce nonwoven mats. Mats with random in-plane fibre orientation can readily be produced using existing commercial processes. However, the fibre volume fraction, and hence the mechanical properties that can be achieved, result in composites with limited mechanical properties. Fibre volume fractions of 40% can be achieved with high moulding pressures of over 100 bar, however, moulding at these pressures results in substantial fibre breakage which reduces the mean fibre length and the properties of the composite manufactured. Nonwoven mats made from aligned, short carbon fibres can achieve higher fibre volume fractions with lower fibre breakage even at high moulding pressure. A process for aligning short fibres is described and a composite of over 60% fibre volume fraction has been manufactured at a pressures up to 100 bar with low fibre breakage. Further developments of the alignment process have been undertaken and a composite of 46% fibre volume fraction has been produced moulded at a pressure of 7 bar in an autoclave, exhibiting good mechanical properties that compete with higher grade materials. This demonstrates the potential for high value applications for recovered carbon fibre by fibre alignment.

  12. FIELD TEST MEASUREMENTS AT FIVE MUNICIPAL SOLID WASTE LANDFILLS WITH LANDFILL GAS CONTROL TECHNOLOGY--FINAL REPORT

    EPA Science Inventory

    Research was conducted to evaluate landfill gas emissions at five municipal solid waste landfills which have modern control technology for landfill gas emissions. Comprehensive testing was conducted on the raw landfill gas and the combustion outlet exhaust. The project had two ...

  13. FIELD TEST MEASUREMENTS AT FIVE MUNICIPAL SOLID WASTE LANDFILLS WITH LANDFILL GAS CONTROL TECHNOLOGY--FINAL REPORT

    EPA Science Inventory

    Research was conducted to evaluate landfill gas emissions at five municipal solid waste landfills which have modern control technology for landfill gas emissions. Comprehensive testing was conducted on the raw landfill gas and the combustion outlet exhaust. The project had two ...

  14. Durability of Waste Glass Flax Fiber Reinforced Mortar

    NASA Astrophysics Data System (ADS)

    Aly, M.; Hashmi, M. S. J.; Olabi, A. G.; Messeiry, M.

    2011-01-01

    The main concern for natural fibre reinforced mortar composites is the durability of the fibres in the alkaline environment of cement. The composites may undergo a reduction in strength as a result of weakening of the fibres by a combination of alkali attack and fibre mineralisation. In order to enhance the durability of natural fiber reinforced cement composites several approaches have been studied including fiber impregnation, sealing of the matrix pore system and reduction of matrix alkalinity through the use of pozzolanic materials. In this study waste glass powder was used as a pozzolanic additive to improve the durability performance of flax fiber reinforced mortar (FFRM). The durability of the FFRM was studied by determining the effects of ageing in water and exposure to wetting and drying cycles; on the microstructures and flexural behaviour of the composites. The mortar tests demonstrated that the waste glass powder has significant effect on improving the durability of FFRM.

  15. Durability of waste glass flax fiber reinforced mortar

    SciTech Connect

    Aly, M.; Hashmi, M. S. J.; Olabi, A. G.; Messeiry, M.

    2011-01-17

    The main concern for natural fibre reinforced mortar composites is the durability of the fibres in the alkaline environment of cement. The composites may undergo a reduction in strength as a result of weakening of the fibres by a combination of alkali attack and fibre mineralisation. In order to enhance the durability of natural fiber reinforced cement composites several approaches have been studied including fiber impregnation, sealing of the matrix pore system and reduction of matrix alkalinity through the use of pozzolanic materials. In this study waste glass powder was used as a pozzolanic additive to improve the durability performance of flax fiber reinforced mortar (FFRM). The durability of the FFRM was studied by determining the effects of ageing in water and exposure to wetting and drying cycles; on the microstructures and flexural behaviour of the composites. The mortar tests demonstrated that the waste glass powder has significant effect on improving the durability of FFRM.

  16. Development of Flax Fibre based Textile Reinforcements for Composite Applications

    NASA Astrophysics Data System (ADS)

    Goutianos, S.; Peijs, T.; Nystrom, B.; Skrifvars, M.

    2006-07-01

    Most developments in the area of natural fibre reinforced composites have focused on random discontinuous fibre composite systems. The development of continuous fibre reinforced composites is, however, essential for manufacturing materials, which can be used in load-bearing/structural applications. The current work aims to develop high-performance natural fibre composite systems for structural applications using continuous textile reinforcements like UD-tapes or woven fabrics. One of the main problems in this case is the optimisation of the yarn to be used to manufacture the textile reinforcement. Low twisted yarns display a very low strength when tested dry in air and therefore they cannot be used in processes such as pultrusion or textile manufacturing routes. On the other hand, by increasing the level of twist, a degradation of the mechanical properties is observed in impregnated yarns (e.g., unidirectional composites) similar to off-axis composites. Therefore, an optimum twist should be used to balance processability and mechanical properties. Subsequently, different types of fabrics (i.e., biaxial plain weaves, unidirectional fabrics and non-crimp fabrics) were produced and evaluated as reinforcement in composites manufactured by well established manufacturing techniques such as hand lay-up, vacuum infusion, pultrusion and resin transfer moulding (RTM). Clearly, as expected, the developed materials cannot directly compete in terms of strength with glass fibre composites. However, they are clearly able to compete with these materials in terms of stiffness, especially if the low density of flax is taken into account. Their properties are however very favourable when compared with non-woven glass composites.

  17. Proceedings from the GRCDA 9th international landfill gas symposium

    SciTech Connect

    Not Available

    1986-01-01

    This book presents the papers given at a conference on methane recovery from sanitary landfills. Topics considered at the conference included hazardous wastes, gaseous wastes, emission, pollution regulations, landfill testing, ambient air monitoring, landfill gas control, methane collection system operation and maintenance, estimating landfill gas yields, the production of high BTU gas, medium BTU gas, the pressure swing MDEA process, landfill gas power conversion, and methane fuel cells.

  18. Monitoring Pre-Stressed Composites Using Optical Fibre Sensors

    PubMed Central

    Krishnamurthy, Sriram; Badcock, Rodney A.; Machavaram, Venkata R.; Fernando, Gerard F.

    2016-01-01

    Residual stresses in fibre reinforced composites can give rise to a number of undesired effects such as loss of dimensional stability and premature fracture. Hence, there is significant merit in developing processing techniques to mitigate the development of residual stresses. However, tracking and quantifying the development of these fabrication-induced stresses in real-time using conventional non-destructive techniques is not straightforward. This article reports on the design and evaluation of a technique for manufacturing pre-stressed composite panels from unidirectional E-glass/epoxy prepregs. Here, the magnitude of the applied pre-stress was monitored using an integrated load-cell. The pre-stressing rig was based on a flat-bed design which enabled autoclave-based processing. A method was developed to end-tab the laminated prepregs prior to pre-stressing. The development of process-induced residual strain was monitored in-situ using embedded optical fibre sensors. Surface-mounted electrical resistance strain gauges were used to measure the strain when the composite was unloaded from the pre-stressing rig at room temperature. Four pre-stress levels were applied prior to processing the laminated preforms in an autoclave. The results showed that the application of a pre-stress of 108 MPa to a unidirectional [0]16 E-glass/913 epoxy preform, reduced the residual strain in the composite from −600 µε (conventional processing without pre-stress) to approximately zero. A good correlation was observed between the data obtained from the surface-mounted electrical resistance strain gauge and the embedded optical fibre sensors. In addition to “neutralising” the residual stresses, superior axial orientation of the reinforcement can be obtained from pre-stressed composites. A subsequent publication will highlight the consequences of pres-stressing on fibre alignment, the tensile, flexural, compressive and fatigue performance of unidirectional E-glass composites. PMID

  19. Monitoring Pre-Stressed Composites Using Optical Fibre Sensors.

    PubMed

    Krishnamurthy, Sriram; Badcock, Rodney A; Machavaram, Venkata R; Fernando, Gerard F

    2016-05-28

    Residual stresses in fibre reinforced composites can give rise to a number of undesired effects such as loss of dimensional stability and premature fracture. Hence, there is significant merit in developing processing techniques to mitigate the development of residual stresses. However, tracking and quantifying the development of these fabrication-induced stresses in real-time using conventional non-destructive techniques is not straightforward. This article reports on the design and evaluation of a technique for manufacturing pre-stressed composite panels from unidirectional E-glass/epoxy prepregs. Here, the magnitude of the applied pre-stress was monitored using an integrated load-cell. The pre-stressing rig was based on a flat-bed design which enabled autoclave-based processing. A method was developed to end-tab the laminated prepregs prior to pre-stressing. The development of process-induced residual strain was monitored in-situ using embedded optical fibre sensors. Surface-mounted electrical resistance strain gauges were used to measure the strain when the composite was unloaded from the pre-stressing rig at room temperature. Four pre-stress levels were applied prior to processing the laminated preforms in an autoclave. The results showed that the application of a pre-stress of 108 MPa to a unidirectional [0]16 E-glass/913 epoxy preform, reduced the residual strain in the composite from -600 µε (conventional processing without pre-stress) to approximately zero. A good correlation was observed between the data obtained from the surface-mounted electrical resistance strain gauge and the embedded optical fibre sensors. In addition to "neutralising" the residual stresses, superior axial orientation of the reinforcement can be obtained from pre-stressed composites. A subsequent publication will highlight the consequences of pres-stressing on fibre alignment, the tensile, flexural, compressive and fatigue performance of unidirectional E-glass composites.

  20. Electrochemical oxidation for landfill leachate treatment

    SciTech Connect

    Deng, Yang Englehardt, James D.

    2007-07-01

    This paper aims at providing an overview of electrochemical oxidation processes used for treatment of landfill leachate. The typical characteristics of landfill leachate are briefly reviewed, and the reactor designs used for electro-oxidation of leachate are summarized. Electrochemical oxidation can significantly reduce concentrations of organic contaminants, ammonia, and color in leachate. Pretreatment methods, anode materials, pH, current density, chloride concentration, and other additional electrolytes can considerably influence performance. Although high energy consumption and potential chlorinated organics formation may limit its application, electrochemical oxidation is a promising and powerful technology for treatment of landfill leachate.

  1. GUIDANCE FOR EVALUATING LANDFILL GAS EMISSIONS ...

    EPA Pesticide Factsheets

    This document provides guidance to Superfund remedial project managers, on scene coordinators, facility owners, and potentially responsible parties for conducting an air pathway analysis for landfill gas (LFG) emissions under the Comprehensive Environmental Response, Compensation and Liability Act, Superfund Amendments and Reauthorization Act, and the Resource Conservation and Recovery Act. The document provides procedures and a set of tools for evaluating LFG emissions to ambient air, subsurface vapor migration due to landfill gas pressure gradients, and subsurface vapor intrusion into buildings. The air pathway analysis is used to evaluate the inhalation risks of offsite receptors as well as the hazards of both onsite and offsite methane explosions and landfill fires. information

  2. Computer optimization of landfill-cover design

    SciTech Connect

    Massmann, J.W.; Moore, C.A.

    1982-12-01

    A finite difference computer program to aid optimizing landfill-cover design was developed. The program was used to compare the methane yield from sand-covred and clay-covered landfills equipped with methane-recovery systems. The results of this comparison indicate a clay cover can restrict air inflow into the landfill system, thus preventing oxygen poisoning of the methane-producing organisms. The practice of monitoring methane-to-air ratios in the pipelines of the recovery system in order to warn of oxygen infiltration into the fill material was shown to be ineffective in some situations. More-reliable methods to forewarn of oxygen poisoning are suggested.

  3. PRAXIS: low thermal emission high efficiency OH suppressed fibre spectrograph

    NASA Astrophysics Data System (ADS)

    Content, Robert; Bland-Hawthorn, Joss; Ellis, Simon; Gers, Luke; Haynes, Roger; Horton, Anthony; Lawrence, Jon; Leon-Saval, Sergio; Lindley, Emma; Min, Seong-Sik; Shortridge, Keith; Staszak, Nick; Trinh, Christopher; Xavier, Pascal; Zhelem, Ross

    2014-07-01

    PRAXIS is a second generation instrument that follows on from GNOSIS, which was the first instrument using fibre Bragg gratings for OH suppression to be deployed on a telescope. The Bragg gratings reflect the NIR OH lines while being transparent to the light between the lines. This gives in principle a much higher signal-noise ratio at low resolution spectroscopy but also at higher resolutions by removing the scattered wings of the OH lines. The specifications call for high throughput and very low thermal and detector noise so that PRAXIS will remain sky noise limited even with the low sky background levels remaining after OH suppression. The optical and mechanical designs are presented. The optical train starts with fore-optics that image the telescope focal plane on an IFU which has 19 hexagonal microlenses each feeding a multi-mode fibre. Seven of these fibres are attached to a fibre Bragg grating OH suppression system while the others are reference/acquisition fibres. The light from each of the seven OH suppression fibres is then split by a photonic lantern into many single mode fibres where the Bragg gratings are imprinted. Another lantern recombines the light from the single mode fibres into a multi-mode fibre. A trade-off was made in the design of the IFU between field of view and transmission to maximize the signal-noise ratio for observations of faint, compact objects under typical seeing. GNOSIS used the pre-existing IRIS2 spectrograph while PRAXIS will use a new spectrograph specifically designed for the fibre Bragg grating OH suppression and optimised for 1.47 μm to 1.7 μm (it can also be used in the 1.09 μm to 1.26 μm band by changing the grating and refocussing). This results in a significantly higher transmission due to high efficiency coatings, a VPH grating at low incident angle and optimized for our small bandwidth, and low absorption glasses. The detector noise will also be lower thanks to the use of a current generation HAWAII-2RG detector

  4. Speciality optical fibres for astronomy

    NASA Astrophysics Data System (ADS)

    Ellis, S. C.; Bland-Hawthorn, J.

    2015-05-01

    Astrophotonics is a rapidly developing area of research which applies photonic technology to astronomical instrumentation. Such technology has the capability of significantly improving the sensitivity, calibration and stability of astronomical instruments, or indeed providing novel capabilities which are not possible using classical optics. We review the development and application of speciality fibres for astronomy, including multi-mode to single-mode converters, notch filters and frequency combs.In particular we focus on our development of instruments designed to filter atmospheric emission lines to enable much deeper spectroscopic observations in the near-infrared. These instruments employ two novel photonic technologies. First, we have developed complex aperiodic fibre Bragg gratings which filter over 100 irregularly spaced wavelengths in a single device, covering a bandwidth of over 200 nm. However, astronomical instruments require highly multi-mode fibres to enable sufficient coupling into the fibre, since atmospheric turbulence heavily distorts the wavefront. But photonic technologies such as fibre Bragg gratings, require single mode fibres. This problem is solved by the photonic lantern, which enables efficient coupling from a multi-mode fibre to an array of single-mode fibres and vice versa. We present the results of laboratory tests of these technologies and of on-sky experiments made using the first instruments to deploy these technologies on a telescope. These tests show that the fibre Bragg gratings suppress the night sky background by a factor of 9. Current instruments are limited by thermal and detector emission. Planned instruments should improve the background suppression even further, by optimising the design of the spectrograph for the properties of the photonic components. Finally we review ongoing research in astrophotonics, including multi-moded multicore fibre Bragg gratings, which enable multiple gratings to be written into the same device

  5. Life cycle assessment (LCA) of solid waste management strategies in Tehran: landfill and composting plus landfill.

    PubMed

    Abduli, M A; Naghib, Abolghasem; Yonesi, Mansoor; Akbari, Ali

    2011-07-01

    As circumstances of operating and maintenance activities for landfilling and composting in Tehran metropolis differ from those of cities in developed countries, it was concluded to have an environmental impact comparison between the current solid waste management (MSW) strategies: (1) landfill, and (2) composting plus landfill. Life cycle assessment (LCA) was used to compare these scenarios for MSW in Tehran, Iran. The Eco-Indicator 99 is applied as an impact assessment method considering surplus energy, climate change, acidification, respiratory effect, carcinogenesis, ecotoxicity and ozone layer depletion points of aspects. One ton of municipal solid waste of Tehran was selected as the functional unit. According to the comparisons, the composting plus landfill scenario causes less damage to human health in comparison to landfill scenario. However, its damages to both mineral and fossil resources as well as ecosystem quality are higher than the landfill scenario. Thus, the composting plus landfill scenario had a higher environmental impact than landfill scenario. However, an integrated waste management will ultimately be the most efficient approach in terms of both environmental and economic benefits. In this paper, a cost evaluation shows that the unit cost per ton of waste for the scenarios is 15.28 and 26.40 US$, respectively. Results show landfill scenario as the preferable option both in environmental and economic aspects for Tehran in the current situation.

  6. Reticulation des fibres lignocellulosiques

    NASA Astrophysics Data System (ADS)

    Landrevy, Christel

    Pour faire face à la crise économique la conception de papier à valeur ajoutée est développée par les industries papetières. Le but de se projet est l'amélioration des techniques actuelles de réticulation des fibres lignocellulosiques de la pâte à papier visant à produire un papier plus résistant. En effet, lors des réactions de réticulation traditionnelles, de nombreuses liaisons intra-fibres se forment ce qui affecte négativement l'amélioration anticipée des propriétés physiques du papier ou du matériau produit. Pour éviter la formation de ces liaisons intra-fibres, un greffage sur les fibres de groupements ne pouvant pas réagir entre eux est nécessaire. La réticulation des fibres par une réaction de « click chemistry » appelée cycloaddition de Huisgen entre un azide et un alcyne vrai, catalysée par du cuivre (CuAAC) a été l'une des solutions trouvée pour remédier à ce problème. De plus, une adaptation de cette réaction en milieux aqueux pourrait favoriser son utilisation en milieu industriel. L'étude que nous désirons entreprendre lors de ce projet vise à optimiser la réaction de CuAAC et les réactions intermédiaires (propargylation, tosylation et azidation) sur la pâte kraft, en milieu aqueux. Pour cela, les réactions ont été adaptées en milieu aqueux sur la cellulose microcristalline afin de vérifier sa faisabilité, puis transférée à la pâte kraft et l'influence de différents paramètres comme le temps de réaction ou la quantité de réactifs utilisée a été étudiée. Dans un second temps, une étude des différentes propriétés conférées au papier par les réactions a été réalisée à partir d'une série de tests papetiers optiques et physiques. Mots Clés Click chemistry, Huisgen, CuAAC, propargylation, tosylation, azidation, cellulose, pâte kraft, milieu aqueux, papier.

  7. Glass recycling

    SciTech Connect

    Dalmijn, W.L.; Houwelingen, J.A. van

    1995-12-31

    Glass recycling in the Netherlands has grown from 10,000 to 300,000 tonnes per annum. The various advantages and problems of the glass cycle with reference to the state of the art in the Netherlands is given. Special attention is given to new technologies for the automated sorting of cullet with detection systems. In Western Europe the recycling of glass has become a success story. Because of this, the percentage of glass cullet used in glass furnaces has increased. To meet the quality demands of the glass industry, automated sorting for the removal of stones, non-ferrous metals and other impurities had to be developed and incorporated in glass recycling plants. In Holland, Germany and other countries, the amount of glass collected has reached a level that color-sorting becomes necessary to avoid market saturation with mixed cullet. Recently, two systems for color-sorting have been developed and tested for the separation of bottles and cullet in the size range of 20--50 mm. With the increased capacity of the new glass recycling plants, 120,000--200,000 tpy, the quality systems have also to be improved and automated. These quality control systems are based on the automated sorting technology developed earlier for the glass recycling plants. The data obtained are automatically processed and printed. The sampling system and its relation to the theory of Gy will be described. Results of both developments in glass recycling plants will be described.

  8. Predicting the tensile modulus and strength of single and hybrid natural fibre reinforced thermoplastic composites

    NASA Astrophysics Data System (ADS)

    Facca, Angelo George

    Natural fibre reinforced thermoplastics (NFRT) are used in a variety of commercial applications, but there is little theoretical modeling of structure/property relationships in these materials. In this thesis, micromechanical models available in the short-fibre literature were adapted to predict the tensile modulus and strength of some NFRT formulations. Hemp, 20 and 40-mesh hardwood, rice hulls and E-glass fibres were blended into HDPE to produce single and hybrid composites. Changes in fibre density and moisture content that occur during composite manufacturing were included in the micromechanical models. To account for fibre densification, the Young's modulus of the natural fibres was determined on a cell wall basis. A modified hybrid rule of mixtures (HROM) equation that uses experimental data from single NFRT was developed and found to adequately predict the tensile modulus of the hybrid composites. The tensile modulus for both the single and hybrid composites was found to linearly increase with an increase in fibre loading. The failure mechanism for all composite specimens was due to fibre pullout followed by matrix failure. Consequently the tensile strength of the NFRT was predicted using a ROM strength equation, which was modified with a derived semi-empirical fibre clustering parameter. The clustering parameter correctly predicted that as fibre loading increased, the average fibre stress would decrease. By assuming no contact between different types of fibres it was possible to use a modified HROM strength equation to predict the tensile strength of the hybrid composites. As a result parameters taken from the respective single fibre systems could be applied directly to the HROM equation. The modified ROM and HROM strength equations adequately predicted the tensile strength of various single and hybrid fibre reinforced composites over a wide range of composite loading. In this study experiments were conducted to shed light on the effect of a coupling agent

  9. Glass Artworks

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Several NASA technologies have played part in growth and cost containment of studio glass art, among them a foam type insulation developed to meet a need for lightweight material that would reduce flame spread in aircraft fire. Foam comes in several forms and is widely used by glass artists, chiefly as an insulator for the various types of ovens used in glass working. Another Spinoff is alumina crucibles to contain molten glass. Before alumina crucibles were used, glass tanks were made of firebrick which tended to erode under high temperatures and cause impurities; this not only improved quality but made the process more cost effective. One more NASA technology that found its way into glass art working is a material known as graphite board, a special form of graphite originally developed for rocket motor applications. This graphite is used to exact compound angles and creates molds for poured glass artworks of dramatic design.

  10. Disaster Debris Recovery Database - Landfills

    EPA Pesticide Factsheets

    The US EPA Region 5 Disaster Debris Recovery Database includes public datasets of over 6,000 composting facilities, demolition contractors, transfer stations, landfills and recycling facilities for construction and demolition materials, electronics, household hazardous waste, metals, tires, and vehicles in the states of Illinois, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, North Dakota, Ohio, Pennsylvania, South Dakota, West Virginia and Wisconsin.In this update, facilities in the 7 states that border the EPA Region 5 states were added to assist interstate disaster debris management. Also, the datasets for composters, construction and demolition recyclers, demolition contractors, and metals recyclers were verified and source information added for each record using these sources: AGC, Biocycle, BMRA, CDRA, ISRI, NDA, USCC, FEMA Debris Removal Contractor Registry, EPA Facility Registry System, and State and local listings.

  11. Fibre prestressed composites: A study of the influences of fibre prestressing on the mechanical properties of polymer matrix composites

    NASA Astrophysics Data System (ADS)

    Motahhari, Siamak

    1998-12-01

    Fibre prestressing during the curing of the polymeric resin is applied in some fabrication processes of composite materials such as filament winding and pultrusion processes. The influences of fibre prestressing on certain mechanical properties have been investigated and justified in the present thesis. Epoxy resin with E-glass fibre and carbon fibre were used to manufacture the samples. The samples were made by applying and holding the tension on the fibres on a horizontal tensiometer machine while the resin was being cured. For glass-epoxy and carbon-epoxy samples different prestressing levels from 10 to 100 MPa and 20 to 140 MPa were applied respectively during the curing of the resin. The samples were made at three different curing temperatures. Flexural strength, flexural modulus, and impact strength of the composites were chosen and measured as representative of the mechanical properties. It was shown that in all cases the studied mechanical properties significantly increased when fibre prestressing increased. The increase of the mechanical properties continued up to a certain fibre prestressing level. Beyond that level, however, the mechanical properties declined. The best fibre prestressing level at which the highest mechanical properties were obtained, was shown to be a function of the curing temperature and the constituent materials of the composites. In the second part of this thesis, the effort has been taken to explain the changes of the mechanical properties caused by fibre prestressing. The residual stresses resulting from the fibre prestressing and resin shrinkage were responsible for the changes of the mechanical properties. A new method was developed to measure the residual stresses which were formed in the composite during the curing process. This method was based of the evaluation of the residual strain in the fibres right after the curing process and removal of applied prestress. Using this method, it was indicated that the residual stresses in

  12. In situ distributions and characteristics of heavy metals in full-scale landfill layers.

    PubMed

    He, Pin-Jing; Xiao, Zheng; Shao, Li-Ming; Yu, Ji-Yu; Lee, Duu-Jong

    2006-10-11

    The leachate from methanogenic landfill normally contains low concentrations of heavy metals. Little samples had ever been collected from the full-scale landfill piles owing to technical difficulty for well drilling. We drilled two wells in Hangzhou Tianziling landfill, 20 m and 32 m in depth each, and collected solid samples of waste age of 1-4 years from both wells. The total amounts, the sequentially extracted amounts, and the chemical binding forms of heavy metals of the samples collected at different depths were measured. With the correlation between leachate production amount and the yearly rainfall amount, the leached ratio of the heavy metals were estimated only 0.13%, 1.8%, 0.15%, and 0.19% of Cu, Cd, Pb, and Zn, respectively. The heavy metals amounts in the main compositions of MSW, like glass, food waste, paper, coal cinders, were measured using fresh MSW samples. Afterward, the contents of heavy metals initially landfilled were estimated. A positive correlation was noted between the measured and the estimated initial contents of heavy metals, indicating that the low migration of heavy metals in landfill layers. However, among the metals investigated, Zn has shown better mobility inside landfill layers. Acid volatile sulfide (AVS) and the simultaneously extracted metals (SEM) were measured for all collected samples with optimal reaction conditions identified to yield nearly perfect sulfide recovery as follows: 100 g wet samples, 80 mL min(-1) N(2) flow rate, reaction time of 150 min. The SEM/AVS ratios ranged 25-45, indicating that the AVS was insufficient to immobilize the SEM. Sequential extraction using six-fraction scheme revealed that the sum of exchangeable and the avid soluble fractions of heavy metals follow: Zn>Cd>Cu, Ni, Pb>Cr. The insoluble fraction of heavy metals in MSW was high, for instance, over 80% for Cr and Pb high insoluble fractions of heavy metals in the landfilled MSW and the sorption capability of the methanogenic landfill layers

  13. Characterisation of CorGlaes(®) Pure 107 fibres for biomedical applications.

    PubMed

    Colquhoun, Ross; Gadegaard, Nikolaj; Healy, David M; Tanner, K Elizabeth

    2016-10-01

    A degradable ultraphosphate (55 mol % P2O5) quinternary phosphate glass composition has been characterised in terms of its chemical, mechanical and degradation properties both as a bulk material and after drawing into fibres. This glass formulation displayed a large processing window simplifying fibre drawing. The fibres displayed stiffness and strength of 65.5 ± 20.8 GPa and 426±143 MPa. While amorphous discs of the glass displayed a linear dissolution rate of 0.004 mg cm(-2) h(-1) at 37 °C, in a static solution with a reduction in media pH. Once drawn into fibres, the dissolution process dropped the pH to <2 in distilled water, phosphate buffer saline and corrected-simulated body fluid, displaying an autocatalytic effect with >90 % mass loss in 4 days, about seven times faster than anticipated for this solution rate. Only cell culture media was able to buffer the pH taking over a week for full fibre dissolution, however, still four times faster dissolution rate than as a bulk material. However, at early times the development of a HCA layer was seen indicating potential bioactivity. Thus, although initial analysis indicated potential orthopaedic implant applications, autocatalysis leads to accelerating degradation in vitro.

  14. Dynamics of topological monopoles annihilation on a fibre in a thick and thin nematic layer.

    PubMed

    Nikkhou, M; Škarabot, M; Čopar, S; Muševič, I

    2016-10-01

    We study topological defect annihilation on a glass fibre with homeotropic surface anchoring of nematic liquid crystal molecules. The fibre is set parallel to the nematic director of a planar cell with variable thickness and we create pairs of Saturn ring and Saturn anti-ring using the laser tweezers. In thick cells we observe in the whole region of defect separation a Coulomb-like pair attraction with no background force, [Formula: see text] with [Formula: see text]. In cells with thickness comparable to glass fibre diameter, we observe the Coulomb-like attraction only at small separations of the defect pair. For separations larger than the fibre diameter, the pair interaction force is independent of separation. This string-like force is attributed to the formation of defect lines, connecting both monopoles and are indeed visible only on extremely confined fibre, where the fibre diameter is practically equal to the nematic layer thickness. Numerical simulations confirm the formation of defect lines connecting both rings.

  15. Ultraviolet radiation (UVR) dosimetry system and the use of Ge-doped silica optical fibres

    NASA Astrophysics Data System (ADS)

    Abdul Rahman, Ahmad Taufek; Abu Bakar, Noor Khairunnisa; Chandra Paul, Mukul; Bradley, D. A.

    2014-11-01

    Previous studies have shown that over exposure to ultraviolet radiation (UVR), either from sunlight or artificial sources, can cause severe biological effects including cataracts, photokeratitis and skin cancer. In this respect, there exists the need to introduce a sensitive UV dosimetric material capable of measuring radiation dose to high accuracy in order to deliver UVR safely and efficiently. Present study has focussed on the investigation of the potential thermoluminescent (TL) sensitivity of commercially available germanium (Ge)-doped silica (SiO2) optical fibres subjected to UVR. The main interest of this study is to find out whether these doped SiO2 optical fibres can be used as a sensible integrator of environmental UV exposures. In the present study, commercially available Ge-doped SiO2 optical fibres have been used with a core diameter of 11 μm (CorActive, Canada), 23 μm (Central Glass and Ceramic Research Institute Kolkata, India) and 50 μm (Central Glass and Ceramic Research Institute Kolkata, India) and a cladding diameter of 125±0.1 μm, irradiated over a wide range of UV dose. Results have shown that these fibres exhibit a linear dose response (with correlation coefficient better than 0.9852). The 50 μm fibre produces greater TL response than that obtained for 11- and 23 μm fibres. The TL results are compared with that of the well-established TL dosimeter material lithium fluoride.

  16. Dichroism measurements in forensic fibre examination: part 5-pigmented fibres.

    PubMed

    De Wael, K; Lepot, L

    2012-09-01

    A number of pigmented fibre samples were examined with plane polarized light on their dichroic behaviour by optical light microscopy (OLM) and microspectrophotometry with plane polarized light (MSP-PPL). It was found that about half of the samples show a strong dichroic effect and another 20% have a weak dichroism. Both regular (80%) and inversed dichroic effects (20%) occur. The dichroic characteristics of pigmented fibres can be compared to these of sheet polarizers. It is suggested that the dichroic behaviour of pigmented fibres depends strongly on the crystal structure (shape of the pigment grains) and the draw ratio (orientation of the polymer chains).

  17. Fibre laser based on tellurium-doped active fibre

    SciTech Connect

    Alyshev, S V; Ryumkin, K E; Shubin, A V; Medvedkov, O I; Dianov, E M; Khopin, V F; Gur'yanov, A N

    2014-02-28

    We have studied the lasing properties of tellurium-doped germanosilicate fibre, identified its gain and excited-state absorption bands, and assessed the effect of cooling to low temperature (77 K) on the bands. The excitation spectrum of the near-IR luminescence in the fibre has been measured. Lasing at 1.55 mm has been demonstrated for the first time in this gain medium at liquidnitrogen temperature and pump wavelengths of 1.064 and 1.085 mm. The measured Raman spectrum of the fibre provides some insight into the structure of the near-IR luminescence centre. (letters)

  18. Modelling flow to leachate wells in landfills

    SciTech Connect

    Al-Thani, A.A.; Beaven, R.P.; White, J.K

    2004-07-01

    Vertical wells are frequently used as a means of controlling leachate levels in landfills. They are often the only available dewatering option for both old landfills without any basal leachate collection layer and for newer sites where the installed drainage infrastructure has failed. When the well is pumped, a seepage face develops at the entry into the well so that the drawdown in the surrounding waste will not be as great as might be expected. The numerical groundwater flow model MODFLOW-SURFACT, which contains the functionality to model seepage surfaces, has been used to investigate the transient dewatering of a landfill. The study concludes that the position of the seepage face and information about the characteristics of the induced seepage flow field are important and should not be neglected when designing wells in landfills.

  19. Operating a fuel cell using landfill gas

    SciTech Connect

    Trippel, C.E.; Preston, J.L. Jr.; Trocciola, J.; Spiegel, R.

    1996-12-31

    An ONSI PC25{trademark}, 200 kW (nominal capacity) phosphoric acid fuel cell operating on landfill gas is installed at the Town of Groton Flanders Road landfill in Groton, Connecticut. This joint project by the Connecticut Light & Power Company (CL&P) which is an operating company of Northeast Utilities, the Town of Groton, International Fuel Cells (IFC), and the US EPA is intended to demonstrate the viability of installing, operating and maintaining a fuel cell operating on landfill gas at a landfill site. The goals of the project are to evaluate the fuel cell and gas pretreatment unit operation, test modifications to simplify the GPU design and demonstrate reliability of the entire system.

  20. Experience with landfill gas monitoring and assessment

    SciTech Connect

    Jenness, S.R.; Wilcox, G.J.

    1998-12-31

    Landfills have recently come under additional environmental scrutiny for their potential as air emission sources. This paper discusses an air monitoring program that was performed in 1997 for the landfill located at US Army Fort Dix, New Jersey. Results of the program are presented as well as conclusions that were drawn from the sampling data and the sampling techniques employed. The Fort Dix Landfill air monitoring program consisted of quarterly measurements of gas vent (more than 50) flow rates. Flow rates were measured twice per day (morning and afternoon) with vane anemometers in order to assess diurnal effects. Measurements of ambient pressure and temperature were also taken for correlation with the gas vent flow rates. Additional gas sampling was performed on selected vents at the landfill to ascertain fixed gases (methane, carbon dioxide, oxygen, and nitrogen) content, total non-methane organic compounds (NMOC), hydrogen sulfide (H{sub 2}S) content, mercury content, and over sixty individual volatile organic compounds (VOCs).