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Sample records for ii resin-modified glass

  1. Comparison of the Amount of Fluoride Release from Nanofilled Resin Modified Glass Ionomer Conventional and Resin Modified Glass Ionomer Cements

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    Sumitha Upadhyay

    2013-01-01

    Full Text Available Objective: To investigate and compare the amount of fluoride release of conventional, resin modified and nanofilled resin modified glass ionomer cements.Materials and Methods: Tablets of glass-ionomer cements were immersed in deionized water and incubated at 37◦C. After 1, 2, 7, 15 and 30 days, fluoride ion was measured under normal atmospheric conditions by fluoride ion selective electrode. Buffer (TISAB II was used to decomplex the fluoride ion and to provide a constant background ionic strength and to maintain the pH of water between 5.0 and 5.5 as the fluoride electrode is sensitive to changes in pH. Statistical evaluation was carried out by one way ANOVA (Analysis of Variance using SPSS 11.0. The significance level was set at p< 0.05.Results: The release of fluoride was highest on day 1 and there was a sudden fall on day 2 in all three groups. Initially fluoride release from conven-tional glass-ionomer cement was highest compared to the other two glass-ionomer cements, but the amount drastically reduced over the period. Although the amount of fluoride release was less than both the resin modified and nanofilled resin modified glass-ionomer cement, the release was sustained consistently for 30 daysConclusion: The cumulative fluoride release of nanofilled resin modified glass ionomer cement was very less compared to the conventional and resin modified glass ionomer cements and Nanofilled resin modified glass ionomer cement released less but steady fluoride as compared to other resin modified glass ionomer cements.

  2. Post cementation sensitivity evaluation of glass Ionomer, zinc phosphate and resin modified glass Ionomer luting cements under class II inlays: An in vivo comparative study

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    Chandrasekhar V

    2010-01-01

    Full Text Available Objective: This study aims to compare the patient-perceived post-cementation sensitivity of class II metal restorations preoperatively, immediately after cementation, one week after cementation and one month after cementation with (1 Glass Ionomer luting cement (2 Zinc Phosphate cement and (3 Resin-modified Glass Ionomer luting cement. Materials and Methods: A total of 60 patients, irrespective of sex, in the age group of 15-50 years were selected and the teeth were randomly divided into three groups of 20 each. Twenty inlay cast restorations were cemented with three different luting cements. The criteria adapted to measure tooth sensitivity in the present study were objective examination for sensitivity.(1 Cold water test (2 Compressed air test and (3 Biting pressure test. Results: The patients with restorations cemented with Resin-modified Glass ionomer demonstrated the least postoperative sensitivity when compared with Glass Ionomer and zinc phosphate cement at all different intervals of time evaluated by different tests. Conclusion: The patients with restorations cemented with resin-modified Glass ionomer demonstrated the least postoperative sensitivity.

  3. In vitro evaluation of microleakage of class II packable composite resin restorations using flowable composite and resin modified glass ionomers as intermediate layers

    OpenAIRE

    Kishore Kumar Majety; Madhu Pujar

    2011-01-01

    Aim and Objectives : To evaluate the cervical marginal microleakage of class II packable composite resin restorations using flowable composite and resin modified glass ionomer as intermediate layers and whether the difference in the thickness of these intermediate layers would influence the microleakage. Materials and Methods : Standardized class II box only cavities (4 mm bucco lingual width 2 mm mesio distal depth with the gingival margin 1 mm above the cemento-enamel junction (CEJ) wer...

  4. Surface finishing of resin-modified glass ionomer.

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    Liporoni, Priscila; Paulillo, Luis Alexandre; Cury, Jaime Aparecido; Dos Santos Dias, Carlos Tadeu; Paradella, Thais Cachute

    2003-01-01

    This study utilized spectrophotometry to evaluate in vitro superficial dye deposition on resin-modified glass ionomer, following different surface finishing and polishing treatments. Materials that were photocured adjacent to the mylar strip produced the surfaces with the lowest mean after superficial staining. A restorative technique without excesses resulted in a smoother surface and prolonged the life of the restoration. The resin-modified glass ionomers tested offer adequate clinical performance.

  5. Resin-modified and conventional glass ionomer restorations in primary teeth: 8-year results

    DEFF Research Database (Denmark)

    Qvist, V.; Manscher, E.; Teglers, P.T.

    2004-01-01

    clinical trial, cariostatic effects, dental restorations, glass ionomer cement, long-term behaviour, pedodontics, resin-modified glass ionomer......clinical trial, cariostatic effects, dental restorations, glass ionomer cement, long-term behaviour, pedodontics, resin-modified glass ionomer...

  6. Comparative evaluation of microleakage between bulk esthetic materials versus resin-modified glass ionomer to restore Class II cavities in primary molars.

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    Gopinath, Vellore Kannan

    2017-01-01

    The aim of the study was to assess the microleakage of one high-viscosity conventional glass ionomer cement (GIC) and a bulk-fill composite resin, in comparison to a resin-modified GIC in Class II restorations in primary molars. Standardized Class II slot cavity preparations were prepared in exfoliating primary molars. Teeth were restored using one of the three materials tested (n = 10): SonicFill bulk-fill composite resin (SF), EQUIA Fil conventional reinforced GIC (EQF), and Vitremer resin-reinforced GIC (VT). The restorations were then subjected to thermocycling procedure (×2000 5°C-55°C 10 s/min) and soaked in 1% neutralized fuchsin solution (pH: 7.4) for 24 h at 37°C. Teeth were sectioned longitudinally in a mesiodistal direction under continuous cooling into three slabs of 1 mm thickness and studied under a stereomicroscope for dye penetration. Data were evaluated by one-way analysis of variance and the Tukey's multiple comparison test employing 95% (α = 0.05). EQF and SF showed significantly lower microleakage scores and percentage of dye penetration (%RL) when compared to VT resin-reinforced GIC (P < 0.001). SF and EQF produced the minimum microleakage when compared to VT in Class II restorations on primary molars. Fewer application procedures and reduction in treatment time in SF and EQF systems proved advantageous in pediatric dentistry.

  7. Comparative evaluation of microleakage between bulk esthetic materials versus resin-modified glass ionomer to restore Class II cavities in primary molars

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    Vellore Kannan Gopinath

    2017-01-01

    Full Text Available Aim: The aim of the study was to assess the microleakage of one high-viscosity conventional glass ionomer cement (GIC and a bulk-fill composite resin, in comparison to a resin-modified GIC in Class II restorations in primary molars. Materials and Method: Standardized Class II slot cavity preparations were prepared in exfoliating primary molars. Teeth were restored using one of the three materials tested (n = 10: SonicFill bulk-fill composite resin (SF, EQUIA Fil conventional reinforced GIC (EQF, and Vitremer resin-reinforced GIC (VT. The restorations were then subjected to thermocycling procedure (×2000 5°C–55°C 10 s/min and soaked in 1% neutralized fuchsin solution (pH: 7.4 for 24 h at 37°C. Teeth were sectioned longitudinally in a mesiodistal direction under continuous cooling into three slabs of 1 mm thickness and studied under a stereomicroscope for dye penetration. Statistical Analysis: Data were evaluated by one-way analysis of variance and the Tukey's multiple comparison test employing 95% (α = 0.05. Results: EQF and SF showed significantly lower microleakage scores and percentage of dye penetration (%RL when compared to VT resin-reinforced GIC (P < 0.001. Conclusion: SF and EQF produced the minimum microleakage when compared to VT in Class II restorations on primary molars. Fewer application procedures and reduction in treatment time in SF and EQF systems proved advantageous in pediatric dentistry.

  8. Modification of resin modified glass ionomer cement by addition of bioactive glass nanoparticles.

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    Valanezhad, Alireza; Odatsu, Tetsuro; Udoh, Koichi; Shiraishi, Takanobu; Sawase, Takashi; Watanabe, Ikuya

    2016-01-01

    In the present study, sol-gel derived nanoparticle calcium silicate bioactive glass was added to the resin-modified light cure glass-ionomer cement to assess the influence of additional bioactive glass nanoparticles on the mechanical and biological properties of resin-modified glass-ionomer cement. The fabricated bioactive glass nanoparticles added resin-modified glass-ionomer cements (GICs) were immersed in the phosphate buffer solution for 28 days to mimic real condition for the mechanical properties. Resin-modified GICs containing 3, 5 and 10 % bioactive glass nanoparticles improved the flexural strength compared to the resin-modified glass-ionomer cement and the samples containing 15 and 20 % bioactive glass nanoparticles before and after immersing in the phosphate buffer solution. Characterization of the samples successfully expressed the cause of the critical condition for mechanical properties. Cell study clarified that resin-modified glass-ionomer cement with high concentrations of bioactive glass nanoparticles has higher cell viability and better cell morphology compare to control groups. The results for mechanical properties and toxicity approved that the considering in selection of an optimum condition would have been a more satisfying conclusion for this study.

  9. Effectiveness of surface protection for resin-modified glass-ionomer materials

    OpenAIRE

    Ribeiro, APG; Serra, MC; Paulillo, LAMS; Rodrigues, AL

    1999-01-01

    Objective: The purpose of this study was to evaluate the effectiveness of various surface treatments for resin-modified glass-ionomer restorative materials by determining dye uptake spectrophotometrically. Method and materials: Two hundred twenty-four specimens, 4.1 mm in diameter and 2.0 mm thick, were made of 3 materials: Vitremer, Fuji II LC, and Photac-Fil Aplicap. Specimens were divided into 15 groups. The positive and negative control specimens remained unprotected, while the experiment...

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

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    Taha NA

    2015-06-01

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

  11. The effects of shelf life on the compressive strength of resin-modified glass ionomer cement

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    Wajong, K. H.; Damiyanti, M.; Irawan, B.

    2017-08-01

    Resin-modified glass ionomer cement (RMGIC) is a restoration material composed of powder and liquid whose stability is affected by its shelf life. This is an issue that has not been taken into consideration by customers or sellers. To observe the effects of shelf life on the compressive strength of RMGIC, 30 cylindrical (d = 4mm and t = 6mm) specimens of RMGIC (Fuji II LC, GC, Tokyo, Japan) were divided into three groups with different storage times and their compressive strength was tested with a universal testing machine. Results were statistically analyzed with the one-way ANOVA test. There were significant differences (pvalue along with the duration of storage time.

  12. Effect of Fluoride-containing Mouthrinses on the Translucence of Resin Modified Glass Ionomer Cements

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    Patrícia Petromilli Nordi Sasso Garcia

    2002-10-01

    Full Text Available The aim of this in vitro study was to assess the effect of different fluoride-containing mouthrinses on the translucence of resin-modified glass ionomer cements, as a function of the restorative material used, the fluoride-containing solution employed and the time of immersion. Disks were prepared (10 mm × 2 mm with the modified glass ionomer cements Vitremer (3M and Fuji II LC (GC Co., and immersed in three fluoride-containing solutions: Fluordent Reach (Johnson & Johnson, Fluorgard (Colgate-Palmolive and Oral B (Gillette do Brasil Ltda. Translucence was measured with electrophoresis equipment (JOUAN after different immersion times. The results obtained were submitted to ANOVA and Tukey's test, and a statistically significant decrease was observed in the translucence of the materials after immersion in the fluoride-containing solutions. Fuji II LC demonstrated the lowest alteration in translucence, independently of the solution employed. Fluorgard was the fluoride-containing mouthrinse that promoted the highest alteration. It can be concluded that the fluoride-containing mouthrinses influenced the translucence of the resin-modified glass ionomer cements.

  13. 5-year clinical performance of resin composite versus resin modified glass ionomer restorative system in non-carious cervical lesions

    DEFF Research Database (Denmark)

    Franco, Eduardo Batista; Benetti, Ana Raquel; Ishikiriama, Sérgio Kiyoshi

    2006-01-01

    To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions.......To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions....

  14. Investigation into the Depth of Cure of Resin-Modified Glass-Ionomer Restorative Materials

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    2006-08-01

    cured glass ionomer and a chemically cured glass ionomer for use as an orthodontic bonding agent. American Journal of Orthodontics and Dentofacial...Sciences Jeffrey M. UK, kb.’ Kraig S. Vanwalle, DDS, MS Approved on 00 ACKNOWLEDGEMENTS This thesis is the result of clinical questions that I have...pondered over years of clinically using resin-modified glass-ionomer restorative materials. Unfortunately, as with all research, as this thesis comes to a

  15. Comparative study of resin sealant and resin modified glass ionomer as pit and fissure sealant

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    Shirin Malek

    2017-02-01

    Full Text Available The purpose of the present study was to compare the marginal integrity of resin modified glass ionomer cement with that of resin sealant, in vitro. Forty artificial pit and fissure cavities were prepared in occlusal surface of extracted premolar teeth by using ¼ round carbide bur. Cavities were condensed with artificial organic debris followed by cleaning with prophylaxis pumice brush and paste and then separated into two treatment groups. In Group A, 15 fissure cavities were sealed by resin sealant and in Group B, 15 fissure cavities were sealed by resin modified glass ionomer sealant. These specimens were subjected to thermo-cycling followed by dye penetration test. The remaining 5 cavities from each group were analyzed for debris score by the SEM. The results of the microleakage test showed that the efficacy of preventing microleakage of samples sealed by resin modified glass ionomer sealant was higher than the samples sealed by resin sealant. However, no significant differences were found. It can be concluded that use of resin modified glass ionomer sealant is a good alternative for sealing pits and fissures.

  16. Histological assessment of pulpal responses to resin modified glass ionomer cements in human teeth

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    Ali Eskandarizadeh

    2015-01-01

    Full Text Available Background: The biocompatibility of resin-modified glass ionomers (RMGIs as a lining material is still under question. The present study evaluated the response of the pulp-dentin complex following application of resin-modified glass-ionomer cement, calcium hydroxide and conventional glass-ionomer in deep cavities prepared in human teeth. Materials and Methods: In this controlled clinical trial, 30 deep class V buccal cavities (3 mm × 2 mm × 2 mm were prepared in human premolars treatment planned to be extracted for orthodontic reasons and divided into 3 groups. Groups were lined by a RMGI (Vivaglass, conventional glass Ionomer (Ionocid and calcium hydroxide respectively. The cavities were subsequently filled with amalgam. Each group was then divided into two sub-groups according to time intervals 5 and 30 days. The patients were referred to Kerman Dental School and in accordance with orthodontic treatment plan; premolars were extracted and then prepared for histological assessment. The sections were stained with hematoxylin and eosin and periodic acid Schiff techniques. All of the samples were examined using a number of criteria including odontoblastic changes, inflammatory cells response, reactionary dentin formation and presence of microorganisms. The data were analyzed by Kruskal-Wallis and Mann-Whitney tests. P 0.05. Conclusion: Ionocid and Vivaglass resin-modified glass ionomers can be used as lining materials in human teeth.

  17. Reducing composite restoration polymerization shrinkage stress through resin modified glass-ionomer based adhesives.

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    Naoum, S J; Mutzelburg, P R; Shumack, T G; Thode, Djg; Martin, F E; Ellakwa, A E

    2015-12-01

    The aim of this study was to determine whether employing resin modified glass-ionomer based adhesives can reduce polymerization contraction stress generated at the interface of restorative composite adhesive systems. Five resin based adhesives (G Bond, Optibond-All-in-One, Optibond-Solo, Optibond-XTR and Scotchbond-Universal) and two resin modified glass-ionomer based adhesives (Riva Bond-LC, Fuji Bond-LC) were analysed. Each adhesive was applied to bond restorative composite Filtek-Z250 to opposing acrylic rods secured within a universal testing machine. Stress developed at the interface of each adhesive-restorative composite system (n = 5) was calculated at 5-minute intervals over 6 hours. The resin based adhesive-restorative composite systems (RBA-RCS) demonstrated similar interface stress profiles over 6 hours; initial rapid contraction stress development (0-300 seconds) followed by continued contraction stress development ≤0.02MPa/s (300 seconds - 6 hours). The interface stress profile of the resin modified glass-ionomer based adhesive-restorative composite systems (RMGIBA-RCS) differed substantially to the RBA-RCS in several ways. Firstly, during 0-300 seconds the rate of contraction stress development at the interface of the RMGIBA-RCS was significantly (p resin modified glass-ionomer based adhesives can significantly reduce the magnitude and rate of polymerization contraction stress developed at the interface of adhesive-restorative composite systems. © 2015 Australian Dental Association.

  18. Dental repair material: a resin-modified glass-ionomer bioactive ionic resin-based composite.

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    Croll, Theodore P; Berg, Joel H; Donly, Kevin J

    2015-01-01

    This report documents treatment and repair of three carious teeth that were restored with a new dental repair material that features the characteristics of both resin-modified glass-ionomer restorative cement (RMGI) and resin-based composite (RBC). The restorative products presented are reported by the manufacturer to be the first bioactive dental materials with an ionic resin matrix, a shock-absorbing resin component, and bioactive fillers that mimic the physical and chemical properties of natural teeth. The restorative material and base/liner, which feature three hardening mechanisms, could prove to be a notable advancement in the adhesive dentistry restorative materials continuum.

  19. MICROLEAKAGE OF CLASS V RESIN-MODIFIED GLASS IONOMER CEMENT AND COMPOMER RESTORATIONS IN VITRO

    Institute of Scientific and Technical Information of China (English)

    DING Ling; LU Yi; LU Qun; XU Qi-hua

    2006-01-01

    Objective To assess the microleakage of Class Ⅴ restorations made with two resin-modified glass ionomer cements (RMGICs) and two polyacid-modified composite resins (PMCRs). Methods Restorations of the four materials ( GC Fuji H LC, VitremerTM, Dyract AP and F2000TM ) were placed in facial Class Ⅴ cavity preparations in forty noncarious human molar teeth. Teeth were randomly assigned to 4 experimental groups of 10 teeth each. After thermal cycling( × 20, 5 -55℃ ), the interface between dentin and restorations was spattercoated with gold and observed under scanning electron microscopy (SEM). Then the square and average width of margin gaps of central 1/3 interface were recorded with image analysis software. Results The data indicated no significant differences between all the restorative materials for both occlusal and gingival margins. Further analysis revealed there were statistically significant differences between occlusal margins and gingival margins for VitremerTM and Dyract AP, respectively. Conclusion None of the tested materials guaranteed margins free of microleakage. Resin-modified glass ionomer cements showed similar margin gaps to the polyacid-modified composite resins tested.

  20. Effect of various amounts of nanosilver incorporation on the mechanical properties of resin modified glass-ionomer cement

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    Roza Haghgoo

    2013-08-01

    Full Text Available   Background and Aims: Metallic nano-particles show exclusive biological, chemical and physical characteristic. The purpose of this research was to evaluate the effect of various amounts of nanosilver incorporation (0 (as control, 20, 40, 80, 120, 200 ppm on the mechanical Properties ( compressive and flexural strength of resin modified Glass ionomer Cement.   Materials and Methods: Based on ISO 4049 and ISO 9971 for polyalkenoid cements, 90 cases in each group were prepared for the flexural and compressive strength. Specimens in 6 groups with different amounts of nanosilver (20, 40, 80, 120 and 200 ppm and control (Fuji II LC improved, stored in distilled water at 37 ° C for 1 day and 30 days. Flexural strength, using a three-point bending method, Modulus of elasticity and the compressive strength were measured by universal testing machine (Zwick with crosshead speed of 0.5 mm/min. Data were analyzed using two-way ANOVA and Tukey post HOC test.   Results: The flexural strength and modulus of various amounts of nanosilver incorporation of resin modified glass-ionomer cement were not significantly different (P>0.05. The compressive strength of incorporating of20 ppm compared with control (P=0.01, 40 ppm (P=0.02 and 80 ppm compared with control (P<0.001 were increased. The flexural strength and compressive strength of Fuji II LC, containing nanosilver particles were increased after 1 day and 1 month significantly (P<0.001.   Conclusion: Incorporation of 20 to 80 ppm nanosilver into Fuji II LC had increased mechanical properties compared to the original cement.

  1. The Evaluation of a Resin-modified Glass Ionome Cement for Bonding Orthodontic Brackets

    Institute of Scientific and Technical Information of China (English)

    LI Fujun; PENG Youjian; PENG Bin

    2009-01-01

    To evaluate the shear bond strength(SBS)and bond failure interface after the debonding of orthodontic brackets with a resin-modified glass ionomer cement(RMGIC)under six bonding conditions,140 premolar teeth were randomly divided into seven groups.The brackets of all groups,except for control group,were bonded using a RMGIC.The teeth were debonded using a universal testing machine.The shear bond strength,adhesive remnant index(ARI)and enamel fracture were examined for each debonding.A significant difference existed in SBS under wet and dry condi-tions in two groups of Fuji Ortho LC.Different degree of enamel fracture was seen in groups of Fuji Ortho LC(dry/37%phosphoric acid treated)after debonding.Bond failed predominantly at the enamel-adhesive interface,except for phosphoric acid treated groups.The RMGIC achieve a clinically effective adhesion in orthodontics under different bonding conditions.

  2. Bone-like apatite layer formation on the new resin-modified glass-ionomer cement.

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    Nourmohammadi, Jhamak; Sadrnezhaad, S K; Ghader, A Behnam

    2008-12-01

    In this study, the apatite-forming ability of the new resin-modified glass-ionomer cement was evaluated by soaking the cement in the simulated body fluid. The Fourier Transform Infrared (FTIR) spectrometer and X-Ray Diffraction (XRD) patterns of the soaked cement pointed to the creation of poorly crystalline carbonated apatite. It was found that the releasing of calcium ions from the soaked cement will dominate the undesirable effect of polyacrylic acid on apatite formation. Consequently, the ionic activity products (IAPs) of the apatite in the surrounding medium increased which accelerated apatite nucleation induced by the presence of the Si-OH and COOH groups. Accordingly, the apatite nuclei started to form via primary heterogeneous nucleation and continued by secondary nucleation. Therefore, nucleation and growth occurs as in the layer-by-layer mode so that finite numbers of monolayers are produced. Subsequent formation of film occurs by formation of discrete nuclei (layer-plus-island or SK growth).

  3. Effect of APF gel on micromorphology of resin modified glass-ionomer cements and flowable compomers.

    Science.gov (United States)

    Benderli, Y; Gökçe, K; Kazak, M

    2005-09-01

    The purpose of this study was to evaluate the surface micromorphology of resin modified glass-ionomer cements and flowable compomers. In the study two resin modified glass-ionomers and two flowable compomers were used to prepare standardized 20 cylinderic samples. Samples were divided into four groups. Surface treatments with APF gel for experimental groups (group B,C,D) or distilled water as a control (group A) were performed four times. In group B, only APF gel was applied. In group C, after the APF gel application, the samples were immersed into the demineralizing and remineralizing solutions. In group D, before the APF gel application, the buffer solution was applied. The examinations of the surface micromorphology of the materials were made by using scanning electron microscope (SEM). Results showed that in group B all of the materials except Compoglass Flow, and in group C all of the materials showed erratic behaviours. In group D, severe erratic effect (score 2) was obtained on the surfaces of Vivaglassliner and Dyract Flow, and for the others score 1 signals were found. The moderate degradation was obtained by applying of only APF gel on the surfaces of both material groups. The addition of pH circulation caused increasing of micromorphologic changes on the surfaces of all materials. The effect of application of buffer solution on the surfaces before APF gel changed according to the materials. If acidulated fluoride gel is preferred for prophylactic therapy in patients' mouth, for the success, either buffer or neutral fluoride have to be applied on the restored teeth by resin based materials before acidulated fluoride application.

  4. Microleakage of conventional, resin-modified, and nano-ionomer glass ionomer cement as primary teeth filling material

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    Dita Madyarani

    2014-12-01

    Full Text Available Background: Glass ionomer cements are one of many dental materials that widely used in pediatric dentistry due to their advantage of fluoride release and chemical bond to tooth structure. Adherence of the filling material to the cavity walls is one of the most important characteristic that need to be examined its effect on microleakage. Purpose: This study was conducted to examine the microleakage of nano-ionomer glass ionomer cement compared with the conventional and resin-modified glass ionomer cements. Methods: Standard class V cavities sized 3 mm x 2 mm x 2 mm were made on a total of 21 extracted maxillary primary canine teeth and restored with the conventional, resin-modified, dan nano-ionomer glass ionomer cements. All the teeth were immersed in a 2% methylene blue dye for 4 hours. The depth of dye penetration was assessed using digital microscope after sectioning the teeth labio-palatally. The results were statistically analyzed using Kruskal-Wallis test. Results: All type of glass ionomer material showed microleakage. Conventional glass ionomer cement demonstrated the least microleakage with mean score 1.29. the resin-modified glass ionomer cements (mean score 1.57 and nano-ionomer glass ionomer cement (mean score 2.57. Conclusion: The conventional glassionomer, resin modified glassionomer, and nano-ionomer glassionomer showed micro leakage as filling material in primary teeth cavity. The micro leakage among three types was not significant difference. All three material were comparable in performance and can be used for filling material but still needs a coating material to fill the microleakage.Latar belakang: Semen ionomer kaca adalah salah satu dari banyak bahan gigi yang banyak digunakan dalam praktek kedokteran gigi anak karena bahan tersebut merilis fluoride dan berikatan kimia dengan struktur gigi. Perlekatan bahan tumpatan pada dinding kavitas adalah salah satu karakteristik paling penting yang perlu diteliti efeknya terhadap

  5. The effect of short polyethylene fiber with different weight percentages on diametral tensile strength of conventional and resin modified glass ionomer cements

    Science.gov (United States)

    Sharafeddin, Farahnaz; Ghaboos, Seyed-Ali

    2017-01-01

    Background The aim of this study was to investigate the effect of polyethylene fiber on diametral tensile strength of conventional and resin modified glass ionomer cements. Material and Methods 60 specimens in 6 groups (n=10) were prepared. In group 1 conventional glass ionomer (Fuji GC) and in group 2 resin modified glass ionomer (Fuji LC) were as control groups. In group 3 and 4 conventional glass ionomers mixed with short polyethylene fibers in proportion of 1 wt% and 3 wt%, respectively. In fifth and sixth groups, resin modified glass ionomer and short polyethylene fibers were mixed in 1 and 3% wt, respectively. Samples were prepared in a round brass mold (6.5×2.5 mm). After thermo-cycling, the diametral tensile strength of the specimens were tested and data were analyzed with ANOVA and post-hoc tests (p<0.05). Results Diametral tensile strength of both conventional and resin modified glass ionomer cements increased after mixing with polyethylene fiber (p<0.001). Also, reinforcement occurred as the mixing percentage increased from 1% wt to 3% wt in either conventional and resin modified glass ionomer (p<0.001). Conclusions The polyethylene fiber was shown to have a significant positive influence on diametral tensile strength of two types of glass ionomers. Key words:Conventional glass ionomer, diametral tensile strength, polyethylene fiber, resin modified glass ionomer. PMID:28298993

  6. Surface hardness properties of resin-modified glass ionomer cements and polyacid-modified composite resins.

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    Bayindir, Yusuf Ziya; Yildiz, Mehmet

    2004-11-15

    In this study the top and bottom surface hardness of two polyacid-modified composite resins (PMCRs), one resin-modified glass ionomer cement (RMGIC), and one composite resin were evaluated. The affect of water storage on their hardness was also investigated. The study was conducted using four different groups, each having five specimens obtained from fiberglass die molds with a diameter of 5 mm and a height of 2 mm. Measurements were made on the top and bottom surface of each specimen and recorded after 24 hours and again at 60 days. All tested materials showed different hardness values, and the values of top surfaces of the specimens were found to be higher than the bottom surface in all test groups. There was no statistical difference in the Vickers hardness (HV) values when the test specimens were kept in water storage. In conclusion Hytac displayed microhardness values higher than Vitremer and Dyract. We found the order of HV values to be Surfil > Hytac > Dyract > Vitremer, respectively. Vitremer presented the lowest microhardness level and Surfil the highest.

  7. Curing depth of a resin-modified glass ionomer and two resin-based luting agents.

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    Sigemori, Ricardo Massao; Reis, André Figueiredo; Giannini, Marcelo; Paulillo, Luís Alexandre M S

    2005-01-01

    The degree of conversion of resin-based luting agents used for retention of prefabricated posts has been questioned due to the difficulty of light penetration into the resin-filled root canal. This study evaluated the depth of cure of a resin-modified glass ionomer cement (Rely X--3M ESPE) and two resin-based luting agents (Rely X ARC--3M ESPE and Enforce-Dentsply). Twenty-four 14x2x2mm3 specimens were prepared in a Teflon split mold with the three luting agents (n=8). After preparation, the specimens were stored at 37 degrees C in a dark box for 24 hours prior to microhardness testing. Measurements of Knoop hardness were performed at three different depths: superficial, medium and deep thirds. The results (KHN) were statistically analyzed by repeated measures ANOVA and Tukey test (0.05), which showed that resin-based luting agents presented the highest Knoop hardness values within the superficial third. Within the medium third, there were no significant differences among luting materials. However, within the deep third, Rely X presented the highest values. KHN values of resin-based luting agents decreased remarkably as depth increased.

  8. Effect of dentine conditioning on adhesion of resin-modified glass ionomer adhesives.

    Science.gov (United States)

    Hamama, H H; Burrow, M F; Yiu, C

    2014-06-01

    The aim of this study was to investigate the use of phosphoric acid as a surface treatment compared to traditional conditioning agents to dentine bonded with resin-modified glass ionomer (RMGIC) adhesives. Forty human molars were utilized in microtensile bond strength testing, while another 16 were used for evaluation of the bonded interface with scanning electron microscopy. Three RMGIC adhesives were evaluated: Fuji Bond LC (GC Corp); Riva Bond LC (SDI Ltd); and Ketac N100 (3M-ESPE). Surface treatments were 37% phosphoric acid (5 s) or 25-30% polyacrylic acid (PAA) (10 s), or the manufacturer's method - Fuji Bond LC: Cavity Conditioner (20% PAA + 3% AlCl3 10 s) or Ketac N100 primer: Ketac Nano priming agent (15 s). Teeth were finished with 600-grit SiC paper, surfaces treated and bonded with RMGIC adhesive and stored in distilled water for 24 h then subjected to microtensile bond strength testing. Two-way analysis of variance (ANOVA) revealed adhesion was affected by the 'type of RMGIC adhesive' and 'method of dentine surface treatment' (p adhesives a brief etch with phosphoric acid does not adversely effect short-term bond strengths, but is no better than traditional conditioning with PAA. © 2014 Australian Dental Association.

  9. Effect of finishing technique on the microleakage and surface texture of resin-modified glass ionomer restorative materials.

    Science.gov (United States)

    Wilder, A D; Swift, E J; May, K N; Thompson, J Y; McDougal, R A

    2000-07-01

    The purpose of this study was to evaluate the effects of wet and dry finishing/polishing procedures on the microleakage and surface texture of resin-modified glass ionomer (RMGI) restorative materials. Class V cavity preparations were made at the cemento-enamel junction (CEJ) on the buccal and lingual surface of 30 extracted human molars. The teeth were restored in three groups of 10 (20 preparations in each group) using Fuji II LC and Vitremer, both RMGIs, and Fuji II, a capsulated conventional glass ionomer cement (control). One restoration per tooth was finished/polished with copious applications of water and the other was finished/polished without water. All restorations were finished/polished using a sequence of four abrasive disks. Finishing/polishing was initiated according to manufacturers' instructions-immediately after light-curing Fuji II LC and Vitremer, and 15min after placement for Fuji II. The specimens were thermocycled and subjected to a silver nitrate leakage test. Each tooth was sectioned buccolingually and examined with an optical microscope at 40x to determine the extent of microleakage at enamel and dentin margins. The data were subjected to a non-parametric statistical analysis. To evaluate surface roughness after polishing, three disks each of Vitremer and Fuji II LC were fabricated in Teflon molds. One disk of each material was not finished/polished (control). The others were finished/polished using Sof-Lex abrasive disks. One specimen of each material was kept wet during all finishing/polishing procedures, while the other was kept dry. Atomic force microscopy was used to determine the average roughness (R(a)) of the specimens. For each material, microleakage at the enamel margin was very slight. Leakage of the conventional glass ionomer Fuji II was severe at dentin margins. Statistical analysis indicated that both Vitremer and Fuji II LC had significantly less leakage than Fuji II, and that Vitremer had significantly less leakage than Fuji

  10. Shear bond strength of resin-modified glass ionomer cements to Er:YAG laser-treated tooth structure.

    Science.gov (United States)

    de Souza-Gabriel, Aline Evangelista; do Amaral, Flávia Lucisano Botelho; Pécora, Jesus Djalma; Palma-Dibb, Regina Guenka; Corona, Silmara Aparecida Milori

    2006-01-01

    This study evaluated the effect of Er:YAG laser irradiation of enamel and dentin on the shear bond strength of resin-modified glass ionomer cements (RMGIC). Twenty molars were selected and the roots removed. The crowns were bisected, embedded in polyester resin and ground to plane the enamel or expose the dentin. The bonding site was delimited, and samples were randomly assigned according to the cavity preparation device: I--Er.YAG laser (350mJ/2Hz); II--Carbide bur (control group). They were subdivided according to the restorative material employed: A) Fuji II LC (GC); B) Vitremer (3M). Samples were then fixed to a metallic device where ionomer cylinders were prepared. Sequentially, the molars were stored for 24 hours and subjected to a shear bond strength test (50Kgf at 0.5 mm/minute). Means in MPa were: Enamel--IA) 4.77 (+/- 1.12); IB) 4.36 (+/- 1.50); IIA) 7.70 (+/- 1.53); IIB) 7.34 (+/- 1.52) and Dentin--IA) 3.13 (+/- 1.15); IB) 2.67 (+/- 0.74); IIA) 6.38 (+/- 1.44); IIB) 5.58 (+/-2.09). Data were submitted to statistical analysis by ANOVA. Adhesion for enamel was more efficient than for dentin (p bond strength values than those recorded for Er:YAG laser (p shear bond strength of RMGIC for both enamel and dentin.

  11. Effect of addition of Nano hydroxyapatite particles on wear of resin modified glass ionomer by tooth brushing simulation

    Science.gov (United States)

    Poorzandpoush, Kiana; Jafarnia, Shiva H.; Golkar, Parisa; Atai, Mohammad

    2017-01-01

    Background Recently, incorporation of nanohydroxyapatite (NHA) has been suggested to improve the mechanical properties of glass ionomers (GIs). This study aimed to assess the effect of addition of NHA on wear of resin modified glass ionomer (RMGI) by tooth brushing simulation. Material and Methods In this in vitro, experimental study, NHA in 1, 2, 5, 7 and 10wt% concentrations was added to Fuji II LC RMGI powder, and 48 samples (5×5mm) in five experimental and one control group (n=8) were fabricated. After polishing, cleaning and incubation at 37°C for three weeks, the samples were weighed and subjected to tooth brushing simulation in a toothpaste slurry according to ISO14569-1. Then, they were weighed again and the weight loss was calculated. The data were analyzed using one-way ANOVA and Tukey’s test. Results The highest and the lowest weight loss was found in the 0% NHA (-1.052±0.176) and 5% NHA (-0.370±0.143) groups, respectively. Wear was significantly higher in 0% NHA group (P<0.05). No difference was detected in wear between 2 and 5wt% NHA or among 1, 7 and 10wt% NHA groups. Significant differences were noted in wear between 2 and 5wt% NHA and 1, 7 and 10wt% NHA groups (P<0.001). Conclusions Incorporation of up to 10wt% of NHA increases the wear resistance of Fuji II LC RMGI. This increase was the highest when 2 and 5wt% NHA were added. Key words:Glass ionomer, hydroxyapatites, nanoparticles, dental restoration wear. PMID:28298977

  12. Microleakage evaluation of class V restorations with conventional and resin-modified glass ionomer cements.

    Science.gov (United States)

    Pontes, Danielson Guedes; Guedes-Neto, Manoel Valcacio; Cabral, Maria Fernanda Costa; Cohen-Carneiro, Flávia

    2014-09-01

    The aim of this study was to evaluate in vitro the marginal microleakage of conventional Glass Ionomer Cements (GIC) and Resin Modified Glass Ionomer Cements (RMGIC). The tested materials were grouped as follows: GIC category - G1 (Vidrion R - SSWhite); G2 (Vitro Fill - DFL); G3 (Vitro Molar - DFL); G4 (Bioglass R - Biodinâmica); and G5 (Ketac Fill - 3M/ESPE); and RMGIC category - G6 (Vitremer - 3M/ESPE); G7 (Vitro Fill LC - DFL); and G8 (Resiglass - Biodinâmica). Therefore, 80 class V cavities (2.0X2.0 mm) were prepared in bovine incisors, either in the buccal face. The samples were randomly divided into 8 groups and restored using each material tested according to the manufacturer. The root apices were then sealed with acrylic resin. The teeth were stored for 24 h in 100% humidity at 37°C. After storage, the specimens were polished with extra-slim burs and silicon disc (Soft-lex - 3M/ESPE), then were isolated with cosmetic nail polish up to 1 mm around the restoration. Then, the samples were immersed in 50% AgNO3 solution for 12 h and in a developing solution for 30 min. They were rinsed and buccal-lingual sectioned. The evaluation of the microleakage followed scores from 0 to 3. The Kruskal-Wallis test and Dunn method test were applied (a=0.05). The results showed that there was no difference between the enamel and dentin margins. However, GIC materials presented more microleakage than RMGIC.

  13. A Twofold Comparison between Dual Cure Resin Modified Cement and Glass Ionomer Cement for Orthodontic Band Cementation

    Science.gov (United States)

    Attar, Hanaa El; Elhiny, Omnia; Salem, Ghada; Abdelrahman, Ahmed; Attia, Mazen

    2016-01-01

    AIM: To test the solubility of dual cure resin modified resin cement in a food simulating solution and the shear bond strength compared to conventional Glass ionomer cement. MATERIALS AND METHOD: The materials tested were self-adhesive dual cure resin modified cement and Glass Ionomer (GIC). Twenty Teflon moulds were divided into two groups of tens. The first group was injected and packed with the modified resin cement, the second group was packed with GIC. To test the solubility, each mould was weighed before and after being placed in an analytical reagent for 30 days. The solubility was measured as the difference between the initial and final drying mass. To measure the Shear bond strength, 20 freshly extracted wisdom teeth were equally divided into two groups and embedded in self-cure acrylic resin. Four mm sections of stainless steel bands were cemented to the exposed buccal surfaces of teeth under a constant load of 500 g. Shear bond strength was measured using a computer controlled materials testing machine and the load required to deband the samples was recorded in Newtons. RESULTS: GIC showed significantly higher mean weight loss and an insignificant lower Shear bond strength, compared to dual cure resin Cement. CONCLUSION: It was found that dual cure resin modified cement was less soluble than glass ionomer cement and of comparable bond strength rendering it more useful clinically for orthodontic band cementation. PMID:28028417

  14. Effect of configuration factor on gap formation in hybrid composite resin, low-shrinkage composite resin and resin-modified glass ionomer.

    Science.gov (United States)

    Boroujeni, Parvin M; Mousavinasab, Sayyed M; Hasanli, Elham

    2015-05-01

    Polymerization shrinkage is one of the important factors in creation of gap between dental structure and composite resin restorations. The aim of this study was to evaluate the effect of configuration factor (C-factor) on gap formation in a hybrid composite resin, a low shrinkage composite resin and a resin modified glass ionomer restorative material. Cylindrical dentin cavities with 5.0 mm diameter and three different depths (1.0, 2.0 and 3.0 mm) were prepared on the occlusal surface of 99 human molars and the cavities assigned into three groups (each of 33). Each group contained three subgroups depend on the different depths and then cavities restored using resin modified glass ionomer (Fuji II LC Improved) and two type composite resins (Filtek P90 and Filtek Z250). Then the restorations were cut into two sections in a mesiodistal direction in the middle of restorations. Gaps were measured on mesial, distal and pulpal floor of the cavities, using a stereomicroscope. Data analyses using Kruskal-Wallist and Mann-Whitney tests. Increasing C-factor from 1.8 to 3.4 had no effect on the gap formation in two type composite resins, but Fuji II LC Improved showed significant effect of increasing C-factor on gap formation. Taken together, when C-factor increased from 1.8 up to 3.4 had no significant effect on gap formation in two tested resin composites. Although, Filtek P90 restorations showed smaller gap formation in cavities walls compared to Filtek Z250 restorations. High C-factor values generated the largest gap formation. Silorane-based composite was more efficient for cavity sealing than methacrylate-based composites and resin modified glass ionomer. © 2014 Wiley Publishing Asia Pty Ltd.

  15. Effects of delayed polymerization time and bracket manipulation on orthodontic resin modified glass ionomer adhesive

    Science.gov (United States)

    Gilbert, Danielle Wiggins

    This study examined the effect of varying delayed polymerization times in combination with bracket manipulation on shear bond strength (SBS), degree of conversion (DC), and adhesive remnant index (ARI) score when using a resin modified glass ionomer (RMGI) adhesive. Specimens were divided into three groups of clinically relevant delay times (0.5, 2, and 4-min) to simulate the delay that frequently occurs between bracket placement and manipulation and subsequent light curing. Based on an analysis of variance (alpha=.05), the SBS was not significantly different between the three groups. While one of the goals of this study was to be the first study to quantify DC of RMGI using Raman microspectroscopy, several challenges, including weak peak signal with and without fluorescence, were encountered and as a result, DC could not be determined. A significant difference (p<0.05) in ARI score was detected between the 0.5-min and 4.0-min delay groups with more adhesive remaining on the bracket with increasing delay time. A Spearman correlation between SBS and ARI indicated no positive association between SBS and ARI measures across delay times. The results of this study suggest that clinically relevant delay times of 0.5, 2, and 4-min do not negatively impact the SBS of a RMGI adhesive. However, with increasing delay time, the results suggest that more adhesive might remain on the bracket during debonding. With more adhesive remaining on the bracket, this could be beneficial in that less adhesive needs to be removed from enamel by grinding at the time of bracket removal when orthodontic treatment is completed.

  16. An evaluation of commercial and experimental resin-modified glass-ionomer cements

    Science.gov (United States)

    Kanchanavasita, Widchaya

    Glass-ionomer cement (GIG) has become widely accepted as a restorative material due to its bonding ability and sustained release of fluoride. The cement is, however, sensitive to moisture imbalance and lacks toughness. Recently, resin-modified glass-ionomer cements (RMGIC) have been introduced. These materials contain monomeric species, such as 2-hydroxyethyl methacrylate (HEMA) in addition to the components of the conventional glass-ionomer cements. Disadvantages of RMGICs include a relatively high contraction and exotherm on polymerisation. HEMA is known to be cytotoxic, leading to problems of biocompatibility, and polyHEMA swells on exposure to water, leading to dimensional instability of the cements. Addressing these problems is important in the development of the RMGICs. Using alternative monomers to replace or reduce the amount of HEMA used in the current RMGIC formulations would be appropriate. This study was divided into two parts. Initially certain properties such as water sorption, micro-hardness, flexural strength and polymerisation exotherm of commercially available RMGICs were evaluated. Long-term storage of RMGICs in aqueous solutions resulted in their high water uptakes and solubilities and large volumetric expansions. However, the surface hardness and strengths of the restorative grade RMGICs were not affected on storage in distilled water. When the materials were immersed in artificial saliva, significantly higher water uptake were obtained; the equilibrium water uptake were not reached after 20 months. As a consequence, plastic behaviour and reduced surface hardness were observed. The RMGICs also produced high exotherm during polymerisation. The second part of the study investigated the use of an experimental resin as an alternative to HEMA. The experimental resin has the advantage of low toxicity to the pulp and relatively low polymerisation shrinkage. This study compared the polymerisations of the resin and HEMA, and of mixtures of these two

  17. Comparative in vitro evaluation of internal adaptation of resin-modified glass ionomer, flowable composite and bonding agent applied as a liner under composite restoration: A scanning electron microscope study.

    Science.gov (United States)

    Soubhagya, M; Goud, K Mallikarjun; Deepak, B S; Thakur, Sophia; Nandini, T N; Arun, J

    2015-04-01

    The use of resin-modified glass Ionomer cement in sandwich technique is widely practiced with the advent of various newer generation of composites the bond between resin-modified glass Ionomer and these resins should be validated. This study is done to evaluate the interfacial microgaps between different types of liners and dentin, liners and composite (Filtek p60 [FLp60]) using scanning electron microscope (SEM). Standardized Class V preparations were performed in buccal/lingual surfaces of 30 caries, crack and defect-free extracted human third molars. The prepared teeth were divided into three groups. Group I: Single bond (SB), Group II: SB + synergy flow, Group III: SB + vitrebond. They were restored with composite resin FLp60, according to the manufacturer instructions. The SB + vitrebond, cross-sectioned through the canter of the restoration. The specimens were fixed, dehydrated, polished, and processed for SEM. The internal adaptation of the materials to the axial wall was analyzed under SEM with ×1000 magnification. The data obtained were analyzed with nonparametric tests (Kruskal-Wallis, P composite or resin-modified glass ionomer applied in conjunction with adhesive resulted in statistically wider microgaps than occurred when the dentin was only hybridized prior to the restoration. Hybridization of dentin only provides superior sealing of the dentin-restoration interface than does flowable resin or resin-modified glass ionomer.

  18. Clinical performance of Class I nanohybrid composite restorations with resin-modified glass-ionomer liner and flowable composite liner: A randomized clinical trial

    Science.gov (United States)

    Suhasini, Krishtipati; Madhusudhana, Koppolu; Suneelkumar, Chinni; Lavanya, Anumula; Chandrababu, K. S.; Kumar, Perisetty Dinesh

    2016-01-01

    Background: Liners play a vital role in minimizing polymerization shrinkage stress by elastic bonding concept and increase the longevity and favorable outcome for composite restorations. Aims: The aim of this study was to evaluate the clinical performance of nanohybrid composite restorations using resin-modified glass-ionomer and flowable composite liners. Settings and Design: A single-centered, double-blinded randomized clinical trial, with split-mouth design and equal allocation ratio that was conducted in the Department of Conservative Dentistry and Endodontics. Materials and Methods: In forty patients, a total of eighty Class I restorations were placed with resin-modified glass-ionomer cement (RMGIC) liner (FUJI II LC, GC America) in one group and flowable composite liner (smart dentin replacement/SDR, Dentsply Caulk, Milford, DE, USA) in another group. All restorations were clinically evaluated by two examiners, immediately (baseline), 3, 6, and 12 months using US Public Health Service modified criteria. Statistical Analysis Used: Statistical analysis was performed using McNemar's test (P < 0.05). Results: There was no significant difference in the color match, marginal discoloration, surface roughness, and marginal adaptation. Restorations with RMGIC liner group show 20% Bravo scores on anatomic form at 12 months but are still clinically acceptable. Conclusion: Nanohybrid composite restorations with RMGIC (Fuji II LC) and flowable composite liner (SDR) demonstrated clinically acceptable performance after 12 months. PMID:27994310

  19. Tensile bond strength of resin-modified glass-ionomer cement to microabraded and silica-coated or tin-plated high noble ceramic alloy.

    Science.gov (United States)

    Swartz, J M; Davis, R D; Overton, J D

    2000-12-01

    The purpose of this study was to evaluate the influence of alloy surface microabrasion, silica coating, or microabrasion plus tin plating on the tensile bond strengths between a resin-modified glass-ionomer luting cement and a high-noble alloy. Bond strength between the microabraded alloy specimens and conventional glass-ionomer cement or resin cement were included for comparison. One hundred twenty uniform size, disk-shaped specimens were cast in a noble metal alloy and divided into 6 groups (n = 10 pairs/group). The metal surfaces of the specimens in each group were treated and cemented as follows. Group 1: No surface treatment (as cast, control), cemented with a resin-modified glass-ionomer cement. Group 2: Microabrasion with 50-microm aluminum oxide particles, resin-modified glass-ionomer cement. Group 3: A laboratory microabrasion and silica coating system, resin-modified glass-ionomer cement. Group 4: Microabrasion and tin-plating, resin-modified glass-ionomer cement. Group 5: Microabrasion only, conventional glass-ionomer cement. Group 6: Microabrasion and tin-plating, conventional resin cement. The uniaxial tensile bond strength for each specimen pair was determined using an Instron Universal Testing Machine (Instron Corp, Canton, MA). Results were analyzed using a one-way analysis of variance (alpha = 0.05) and a Tukey post-hoc analysis. Mean bond strength: Group 1: 3.6 (+/- 1.5) MPa. Group 2: 4.2 (+/-0.5) MPa. Group 3: 6.7 (+/- 0.9) MPa. Group 4: 10.6 (+/- 1.8) MPa. Group 5: 1.1 (+/- 0.4) MPa. Group 6: 14.6 (+/- 2.3) MPa. Group 6 was significantly stronger than Group 4. The bond strength of specimens cemented with the resin-modified glass-ionomer cement using microabrasion and tin-plating (Group 4) was significantly stronger than all other groups except the resin cement with microabrasion and tin-plating (Group 6). Microabraded and tin-plated alloy specimens luted with the resin-modified glass-ionomer cement resulted in the greatest mean tensile strengths

  20. Marginal microleakage of resin-modified glass-ionomer and composite resin restorations: Effect of using etch-and-rinse and self-etch adhesives

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2012-01-01

    Full Text Available Objectives: Previous studies have shown that dental adhesives increase the bond strength of resin-modified glass-ionomer (RMGI restorative materials to dentin. This in vitro study has evaluated the effect of etch-and-rinse and self-etch bonding systems v/s cavity conditioner, and in comparison to similar composite resin restorations on maintaining the marginal sealing of RMGI restorations. Materials and Methods: 98 rectangular cavities (2.5×3×1.5 mm were prepared on buccal and palatal aspects of 49 human maxillary premolars, randomly divided into 7 groups (N=14. The cavities in groups 1, 2 and 3 were restored using a composite resin (APX. The cavities in groups 4, 5, 6 and 7 were restored using a resin-modified glass-ionomer (Fuji II LC. Before restoring, adhesive systems (Optibond FL = OFL, three-step etch-and-rinse; One Step Plus = OSP, two-step etch-and-rinse; Clearfil Protect Bond = CPB, two-step self-etch were used as bonding agents in groups 1-6 as follow: OFL in groups 1 and 4, OSP in groups 2 and 5, and CPB in groups 3 and 6, respectively. The specimens in group 7 were restored with GC cavity conditioner and Fuji II LC. All the specimens were thermo-cycled for 1000 cycles. Microleakage scores were determined using dye penetration method. Statistical analyzes were carried out with Kruskal-Wallis and Mann-Whitney U tests (α=0.05. Results: There were significant differences in microleakage scores at both enamel and dentinal margins between the study groups (P<0.05. The lowest microleakage scores at enamel and dentin margins of RMGI restorations were observed in group 6. Conclusion: Use of two-step self-etch adhesive, prior to restoring cervical cavities with RMGIC, seems to be more efficacious than the conventional cavity conditioner in decreasing marginal microleakage.

  1. A comparison study on the flexural strength and compressive strength of four resin-modified luting glass ionomer cements.

    Science.gov (United States)

    Li, Yuan; Lin, Hong; Zheng, Gang; Zhang, Xuehui; Xu, Yongxiang

    2015-01-01

    The purpose of this study is to compare the differences in flexural strength and compressive strength between four resin-modified luting glass ionomer cements that are commonly used in clinics. Furthermore, this study investigates the influence of curing mode on the flexural strength and compressive strength of dual-cured resin-modified glass ionomer cements. Initially, flexural strength and compressive strength test specimens were prepared for RL, NR, GCP, and GCC. The RL group and NR group were cured by the light-curing mode and chemical-curing mode. Five specimens were prepared for each test group, and the flexural strength and compressive strength of each were measured. Data were analyzed by one-way ANOVA with SPSS 13.0. Furthermore, the fracture morphology of the flexural specimens was observed by SEM. The result of the mean flexural strength of each group is as follows: the NR light-cured group > NR chemically-cured group > GCP > RL light-cured group > GCC > RL chemically-cured group. More specifically, the flexural strength of the NR light-cured group ((42.903±4.242) MPa) is significantly higher (P NR chemically-cured group > NR light-cured group > GCC > RL light-cured group > RL chemically-cured group. Although the compressive strengths of the NR and GCP groups are higher than those of the GCC and RL groups, there are no significant differences (P>0.05) between NR and GCP, and no significant differences between GCC and RL. Furthermore, there are no significant differences (P>0.05) between the two curing modes on NR and RL. From the present study, it can be concluded that NR has superior flexural strength and compressive strength compared to the other three materials. Additionally, the curing mode can affect the flexural strength of dual-cured RMGIC because with the light-curing mode, the flexural strength is higher than with the chemical-curing mode. Therefore, light curing is an essential procedure when using dual-cured RMGIC in clinics.

  2. Evaluation of micro-shear bond strength of resin modified glass-ionomer to composite resins using various bonding systems

    Directory of Open Access Journals (Sweden)

    Shahin Kasraie

    2013-01-01

    Full Text Available Aim: The aim was to compare the micro-shear bond strength between composite and resin-modified glass-ionomer (RMGI by different adhesive systems. Materials and Methods: A total of 16 discs of RMGI with a diameter of 15 mm and a thickness of 2 mm were randomly divided into four groups (n = 4. Four cylinders of composite resin (z250 were bonded to the RMGI discs with Single Bond, Clearfil SE Bond and Clearfil S3 Bond in Groups 1-3, respectively. The fourth group was the control. Samples were tested by a mechanical testing machine with a strain rate of 0.5 mm/min. Failure mode was assessed under a stereo-microscope. Results: The means of micro-shear bond strength values for Groups 1-4 were 14.45, 23.49, 16.23 and 5.46 MPa, respectively. Using a bonding agent significantly increased micro-shear bond strength (P = 0.0001. Conclusion: Micro-shear bond strength of RMGI to composite increased significantly with the use of adhesive resin. The bond strength of RMGI to composite resin could vary depending upon the type of adhesive system used.

  3. Effect of chemomechanical caries removal on bonding of resin-modified glass ionomer cement adhesives to caries-affected dentine.

    Science.gov (United States)

    Hamama, Hhh; Yiu, Cky; Burrow, M F

    2015-06-01

    This study evaluated the effect of: (1) chemomechanical caries removal (CMCR); (2) dentine surface treatments and (3) dentine substrates on adhesion of resin-modified glass ionomer cement (RMGIC) adhesives. One hundred and twenty permanent molars exhibiting moderate cavitation on the occlusal surface into dentine were used. Seventy-five carious molars were used for bond strength testing; the remaining 45 for micromorphological evaluation of the bonded interface. Caries was excavated with NaOCl-based CMCR (Carisolv), enzyme-based CMCR (Papacarie), or conventional rotary caries removal methods. Dentine surface treatment was performed using 37% phosphoric acid, 25-30% PAA or 20% PAA + 3% AlCl3 . Three-way ANOVA revealed that all three factors 'caries removal methods', 'dentine surface treatments' and 'dentine substrates' did not significantly affect bond strength (p > 0.05). Scanning electron microscopy micrographs showed that the acid-base resistant layer was thicker in caries-affected dentine compared to sound dentine. NaOCl- and enzyme-based CMCR methods have no adverse effect on adhesion of RMGIC adhesives to sound and caries-affected dentine. Dentine surface treatment with 37% phosphoric acid for 5 s has no negative effect on bonding of RMGIC adhesives to dentine compared with using polyacrylic acid for 10 s. RMGIC adhesives bonded well to both sound and caries-affected dentine. © 2015 Australian Dental Association.

  4. Effect of novel chitosan-fluoroaluminosilicate resin modified glass ionomer cement supplemented with translationally controlled tumor protein on pulp cells.

    Science.gov (United States)

    Wanachottrakul, Nattaporn; Chotigeat, Wilaiwan; Kedjarune-Leggat, Ureporn

    2014-04-01

    Dental materials that can promote cell proliferation and function is required for regenerative pulp therapy. Resin modified glass ionomer cement (RMGIC), a broadly used liner or restorative material, can cause apoptosis to pulp cells mainly due to HEMA (2-hydroxyethyl methacrylate), the released residual monomer. Recent studies found that chitosan and albumin could promote release of protein in GIC while translationally controlled tumor protein (TCTP) has an anti-apoptotic activity against HEMA. The aim of this study was to examine the effect of chitosan and albumin modified RMGIC (Exp-RMGIC) supplemented with TCTP on pulp cell viability and mineralization. Exp-RMGIC+TCTP was composed of RMGIC powder incorporated with 15 % of chitosan, 5 % albumin and supplemented with TCTP mixed with the same liquid components of RMGIC. The effect of each specimen on pulp cells was examined using the Transwell plate. From the MTT assay, Exp-RMGIC+TCTP had the highest percentages of viable cells (P supplemented with TCTP had less cytotoxicity than RMGIC and can protect cells from apoptosis better than RMGIC supplemented with TCTP.

  5. Setting Reaction of Dental Resin-Modified Glass Ionomer Restoratives as a Function of Curing Depth and Postirradiation Time

    Directory of Open Access Journals (Sweden)

    Young Kyung Kim

    2015-01-01

    Full Text Available Specular reflectance Fourier transform infrared (SR-FTIR spectroscopy was used to study the setting reaction of dental resin-modified glass ionomer (RMGI restoratives as a function of curing depth and postirradiation time. Two light-cure and one tri-cure RMGI materials were selected and used according to the manufacturers’ instructions. Samples were prepared by filling the mixed materials into custom-made molds and then light-irradiating using a dental curing light. The degree of conversion and the extent of acid-base reaction of the materials at different depths (0, 1, 2, and 4 mm and postirradiation times (10 min, 1 day, and 7 days were determined using SR-FTIR spectroscopy in conjunction with the Kramers-Kronig (K-K transformation. The setting reaction was also investigated using microhardness measurements. The results showed that the depth of cure increased over time by the continuous acid-base reaction rather than photopolymerization or chemical polymerization. Microhardness tests seemed less suitable for studying the setting reaction as a function of postirradiation time, probably due to softening from the humidity. Analysis using specular reflectance in conjunction with the K-K algorithm was an easy and effective method for monitoring the setting reaction of dental RMGI materials.

  6. Clinical evaluation of resin composite and resin-modified glass ionomer cement in non-carious cervical lesions.

    Science.gov (United States)

    Adeleke; Oginni, Ao

    2012-10-01

    The clinical performance of various tooth-coloured materials used to restore Non-Carious Cervical Lesions (NCCLs) has been evaluated. However, most of these evaluations were in western societies where soft diets requiring little mastication were common. The present study sets out to evaluate resin composite and RMGIC in the restoration of NCCLs among a Nigerian subpopulation group with fibrous diet requiring more rigorous mastication. The study included all adult patients that presented at the Dental Hospital, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria with non-carious cervical lesions over a period of six months. The teeth with non-carious cervical lesions in each patient were allocated into treatment with either resin composite or resin-modified glass ionomer cement by simple random sampling using ballots. The depth of the NCCLs was measured using a graduated flat ash periodontal probe. All the treatment was done by the first author according to the manufacturer's instructions. Patients were recalled and evaluated at 48- hours, 3- months, 6- months and 12- months using the USPHS criteria. Data analysis was done using SPSS version 15. The level of significance was put at 0.05. At the end of 12 months, 143 resin composite and 144 RMGIC restorations were evaluated, out of which 37 resin composite and 13 RMGIC restorations were dislodged, giving a retention rate of 74.1% and 91.0% respectively. The difference was statistically significant (pcarious cervical lesions than resin composite over a period of 12 month.

  7. The effect of polishing systems on microleakage of tooth coloured restoratives: Part 1. Conventional and resin-modified glass-ionomer cements.

    Science.gov (United States)

    Yap, A U; Tan, S; Teh, T Y

    2000-02-01

    The purpose of this in vitro study was to investigate the effect of polishing systems on the microleakage of conventional and resin-modified glass-ionomer cements. Class V cavities were prepared at the cemento-enamel junction of 80 freshly extracted posterior teeth. The prepared teeth were randomly divided into two groups and restored with conventional or resin-modified glass-ionomer cements. The restored teeth were stored in distilled water at 37 degrees C for 1 week after removal of excess restorative with diamond finishing burs. The restored teeth were then divided into four groups of 10 and finished and polished using the following systems: Two Striper MFS; Sof-Lex XT; Enhance Composite Finishing and Polishing System; Shofu Composite Finishing Kit. The finished restorations were subjected to dye penetration testing. Results showed that the microleakage at dentin margins of conventional glass-ionomer cements and enamel margins of resin-modified glass-ionomer cements are significantly affected by the different polishing systems.

  8. Push-out bond strength of fiber posts to root dentin using glass ionomer and resin modified glass ionomer cements

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    Jefferson Ricardo PEREIRA

    2014-10-01

    Full Text Available OBJECTIVE: The purpose of this study was to assess the push-out bond strength of glass fiber posts to root dentin after cementation with glass ionomer (GICs and resinmodified glass ionomer cements (RMGICs. MATERIAL AND METHODS: Fifty human maxillary canines were transversally sectioned at 15 mm from the apex. Canals were prepared with a step back technique until the application of a #55 K-file and filled. Post spaces were prepared and specimens were divided into five groups according to the cement used for post cementation: Luting & Lining Cement; Fuji II LC Improved; RelyX Luting; Ketac Cem; and Ionoseal. After cementation of the glass fiber posts, all roots were stored at 100% humidity until testing. For push-out test, 1-mm thick slices were produced. The push-out test was performed in a universal testing machine at a crosshead speed of 0.5 mm/minute and the values (MPa were analyzed by Kolmogorov-Smirnov and Levene's tests and by two-way ANOVA and Tukey's post hoc test at a significance level of 5%. RESULTS: Fiber posts cemented using Luting & Lining Cement, Fuji II LC Improved, and Ketac Cem presented the highest bond strength to root dentin, followed by RelyX Luting. Ionoseal presented the lowest bond strength values (P>0.05. The post level did not influence the bond strength of fiber posts to root dentin (P=0.148. The major cause of failure was cohesive at the cement for all GICs and RMGICs. CONCLUSIONS: Except for Ionoseal, all cements provided satisfactory bond strength values.

  9. Shear bond strength evaluation of resin composite to resin-modified glass-ionomer cement using three different resin adhesives vs. glass-ionomer based adhesive

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    Mostafa Sadeghi

    2015-12-01

    Full Text Available Background: The clinical success of sandwich technique depends on the strength of resin-modified glass ionomer cement (RMGIC bonding to both dentin and resin composite. Therefore, the shear bond strength (SBS of resin composite bonded to RMGIC utilizing different resin adhesives versus a GIC-based adhesive was compared. Materials and methods: In this in vitro study, 84 holes (5×2 mm were prepared in acrylic blocks, randomly divided into seven groups (n=12 and filled with RMGIC (Light-Cured Universal Restorative, GC. In the Group I; no adhesive was applied on the RMGIC. In the Group II, non-etched and Group III was etched with phosphoric acid. In groups II and III, after rinsing, etch-and-rinse adhesive (OptiBond Solo Plus; in the Group IV; a two-step self-etch adhesive (OptiBond XTR and in Group V; a one-step self-etch (OptiBond All-in-One were applied on the cement surfaces. Group VI; a GIC-based adhesive (Fuji Bond LC was painted over the cement surface and cured. Group VII; the GIC-based adhesive was brushed over RMGIC followed by the placement of resin composite and co-cured. Afterward; resin composite (Point 4 cylinders were placed on the treated cement surfaces. The specimens were placed in 100% humidity at 37 ± 1°C and thermo cycled. The shear bond test was performed at a cross-head speed of 1 mm/min and calculated in MPa; the specimens were examined to determine mode of failure. The results were analyzed using one-way ANOVA and Tukey test. Results: The maximum (24.62±3.70 MPa and minimum (18.15±3.38 MPa SBS mean values were recorded for OptiBond XTR adhesive and the control group, respectively. The pairwise comparisons showed no significant differences between the groups that bonded with different adhesives. The adhesive failure was the most common failure mode observed. Conclusion: This study suggests that GIC-based adhesive could be applied over RMGIC as co-cure technique for sandwich restorations in lieu of employing the resin

  10. Influence of air-abrasion executed with polyacrylic acid-Bioglass 45S5 on the bonding performance of a resin-modified glass ionomer cement.

    Science.gov (United States)

    Sauro, Salvatore; Watson, Timothy F; Thompson, Ian; Toledano, Manuel; Nucci, Cesare; Banerjee, Avijit

    2012-04-01

    The aim of this study was to test the microtensile bond strength (μTBS), after 6 months of storage in PBS, of a resin-modified glass ionomer cement (RMGIC) bonded to dentine pretreated with Bioglass 45S5 (BAG) using various etching and air-abrasion techniques. The RMGIC (GC Fuji II LC) was applied onto differently treated dentine surfaces followed by light curing for 30 s. The specimens were cut into matchsticks with cross-sectional areas of 0.9 mm(2). The μTBS of the specimens was measured after 24 h or 6 months of storage in PBS and the results were statistically analysed using two-way anova and the Student-Newman-Keuls test (α = 0.05). Further RMCGIC-bonded dentine specimens were used for interfacial characterization, micropermeability, and nanoleakage analyses by confocal microscopy. The RMGIC-dentine interface layer showed no water absorption after 6 months of storage in PBS except for the interdiffusion layer of the silicon carbide (SiC)-abraded/polyacrylic acid (PAA)-etched bonded dentine. The RMGIC applied onto dentine air-abraded with BAG/H(2)O only or with BAG/PAA-fluid followed by etching procedures (10% PAA gel) showed no statistically significant reduction in μTBS after 6 months of storage in PBS. The abrasion procedures performed using BAG in combination with PAA might be a suitable strategy to enhance the bonding durability and the healing ability of RMGIC bonded to dentine.

  11. Comparison of Elastic Modulus and Compressive Strength of Ariadent and Harvard Polycarboxylate Cement and Vitremer Resin Modified Glass Ionomer

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    Ahmadian Khoshemehr Leila

    2009-09-01

    Full Text Available Background: Luting agents are used to attach indirect restoration into or on the tooth. Poor mechanical properties of cement may be a cause of fracture of this layer and lead to caries and restoration removal. The purpose of this study was to compare the elastic modulus and compressive strength of Ariadent (A Poly and Harvard polycarboxylate (H Poly cements and Vitremer resin modified glass ionomer (RGl.Materials & Methods: In this experimental study 15 specimens were prepared form each experimental cement in Laboratory of Tehran Oil Refining Company. The cylindrical specimens were compressed in Instron machine after 24 hours. Elastic modulus and compressive strength were calculated from stress/strain curve of each specimen. One way ANOVA and Tukey tests were used for statistical analysis and P values<0.05 were considered to be statistically significant.Results: The mean elastic modulus and mean compressive strength were 2.2 GPa and 87.8MPa in H poly, 2.4 GPa and 56.5 MPa in A Poly, and 0.8GPa and 105.6 MPa in RGI, respectively. Statistical analysis showed that compressive strength and elastic modulus of both polycarboxylate cements were significantly different from hybrid ionomer (P<0.05, but the difference between elastic modulus of two types of polycarboxilate cements was not statistically significant. Compressive strength of two polycarboxilate cements were significantly different (P<0.05. Conclusion: An ideal lutting agent must have the best mechanical properties. Between the tested luttins RGl cement had the lowest elastic modulus and the highest compressive strength, but the A poly cement had the highest elastic modulus and the lowest compressive strength. Therefore none of them was the best.

  12. Shear Bond Strength of Self-Adhering Flowable Composite and Resin-modified Glass Ionomer to Two Pulp Capping Materials

    Science.gov (United States)

    Doozaneh, Maryam; Koohpeima, Fatemeh; Firouzmandi, Maryam; Abbassiyan, Forugh

    2017-01-01

    Introduction: The aim of this study was to compare the shear bond strength of a self-adhering flowable composite (SAFC) and resin-modified glass ionomer (RMGI) to mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement. Methods and Materials: A total of 72 acrylic blocks with a central hole (4 mm in diameter and 2 mm in depth) were prepared. The holes were filled with MTA (sub group A) and CEM cement. The specimens of both restorative materials were divided into 6 groups; overall there were 12 groups. In groups 1 and 4, SAFC was used without bonding while in groups 2 and 5 SAFC was used with bonding agent. In all these groups the material was placed into the plastic mold and light cured. In groups 3 and 6, after surface conditioning with poly acrylic acid and rinsing, RMGI was placed into the mold and photo polymerized. After 24 h, the shear bond strength values were measured and fracture patterns were examined by a stereomicroscope. Data were analyzed using the two-way ANOVA and student’s t-test. Results: The use of bonding agent significantly increased the shear bond strength of FC to MTA and CEM cement (P=0.008 and 0.00, respectively). In both materials, RMGI had the lowest shear bond strength values (2.25 Mpa in MTA and 1.32 Mpa in CEM). The mean shear bond strength were significantly higher in MTA specimen than CEM cement (P=0.003). There was a significant differences between fracture patterns among groups (P=0.001). Most failures were adhesive/mix in MTA specimen but in CEM cement groups the cohesive failures were observed in most of the samples. Conclusion: The bond strength of self-adhering flowable composite resin to MTA and CEM cement was higher than RMGI which was improved after the additional application of adhesive. PMID:28179935

  13. Improvement of enamel bond strengths for conventional and resin-modified glass ionomers: acid-etching vs. conditioning*

    Science.gov (United States)

    Zhang, Ling; Tang, Tian; Zhang, Zhen-liang; Liang, Bing; Wang, Xiao-miao; Fu, Bai-ping

    2013-01-01

    Objective: This study deals with the effect of phosphoric acid etching and conditioning on enamel micro-tensile bond strengths (μTBSs) of conventional and resin-modified glass ionomer cements (GICs/RMGICs). Methods: Forty-eight bovine incisors were prepared into rectangular blocks. Highly-polished labial enamel surfaces were either acid-etched, conditioned with liquids of cements, or not further treated (control). Subsequently, two matching pre-treated enamel surfaces were cemented together with one of four cements [two GICs: Fuji I (GC), Ketac Cem Easymix (3M ESPE); two RMGICs: Fuji Plus (GC), RelyX Luting (3M ESPE)] in preparation for μTBS tests. Pre-treated enamel surfaces and cement-enamel interfaces were analyzed by scanning electron microscopy (SEM). Results: Phosphoric acid etching significantly increased the enamel μTBS of GICs/RMGICs. Conditioning with the liquids of the cements produced significantly weaker or equivalent enamel μTBS compared to the control. Regardless of etching, RMGICs yielded stronger enamel μTBS than GICs. A visible hybrid layer was found at certain enamel-cement interfaces of the etched enamels. Conclusions: Phosphoric acid etching significantly increased the enamel μTBSs of GICs/RMGICs. Phosphoric acid etching should be recommended to etch the enamel margins before the cementation of the prostheses such as inlays and onlays, using GICs/RMGICs to improve the bond strengths. RMGICs provided stronger enamel bond strength than GICs and conditioning did not increase enamel bond strength. PMID:24190447

  14. Bond strength of resin modified glass ionomer cement to primary dentin after cutting with different bur types and dentin conditioning

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    Rebeca Di Nicoló

    2007-10-01

    Full Text Available The aim of this in vitro study was to evaluate the effect of different bur types and acid etching protocols on the shear bond strength (SBS of a resin modified glass ionomer cement (RM-GIC to primary dentin. Forty-eight clinically sound human primary molars were selected and randomly assigned to four groups (n=12. In G1, the lingual surface of the teeth was cut with a carbide bur until a 2.0-mm-diameter dentin area was exposed, followed by the application of RM-GIC (Vitremer - 3M/ESPE prepared according to the manufacturer's instructions. The specimens of G2, received the same treatment of G1, however the dentin was conditioned with phosphoric acid. In groups G3 and G4 the same procedures of G1 and G2 were conducted respectively, nevertheless dentin cutting was made with a diamond bur. The specimens were stored in distilled water at 37ºC for 24h, and then tested in a universal testing machine. SBS. data were submitted to 2-way ANOVA (= 5% and indicated that SBS values of RM-GIC bonded to primary dentin cut with different burs were not statistically different, but the specimens that were conditioned with phosphoric acid presented SBS values significantly higher that those without conditioning. To observe micromorphologic characteristics of the effects of dentin surface cut by diamond or carbide rotary instruments and conditioners treatment, some specimens were examined by scanning electron microscopy. Smear layer was present in all specimens regardless of the type of rotary instrument used for dentin cutting, and specimens etched with phosphoric acid presented more effective removal of smear layer. It was concluded that SBS of a RM-GIC to primary dentin was affected by the acid conditioning but the bur type had no influence.

  15. Microleakage after Thermocycling of Three Self-Etch Adhesives under Resin-Modified Glass-Ionomer Cement Restorations

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    Sabine O. Geerts

    2010-01-01

    Full Text Available This study was designed to evaluate microleakage that appeared on Resin-Modified Glass-Ionomer Cement (RMGIC restorations. Sixty class V cavities (h×w×l=2mm×2mm×3mm were cut on thirty extracted third molars, which were randomly allocated to three experimental groups. All the buccal cavities were pretreated with polyacrylic acid, whereas the lingual cavities were treated with three one-step Self-Etch adhesives, respectively, Xeno III (Dentsply Detrey GmbH, Konstanz, Germany, iBond exp (Heraeus Kulzer gmbH & Co. KG, Hanau, Germany, and Adper Prompt-L-Pop (3M ESPE AG, Dental products Seefeld, Germany. All cavities were completely filled with RMGIC, teeth were thermocycled for 800 cycles, and leakage was evaluated. Results were expressed as means ± standard deviations (SDs. Microleakage scores were analysed by means of generalized linear mixed models (GLMMs assuming an ordinal logistic link function. All results were considered to be significant at the 5% critical level (<.05. The results showed that bonding RMGIC to dentin with a Self-Etch adhesive rather than using polyacrylic acid did not influence microleakage scores (=.091, except for one tested Self-Etch adhesive, namely, Xeno III (<.0001. Nevertheless, our results did not show any significant difference between the three tested Self-Etch adhesive systems. In conclusion, the pretreatment of dentin with Self-Etch adhesive system, before RMGIC filling, seems to be an alternative to the conventional Dentin Conditioner for the clinicians as suggested by our results (thermocycling and others (microtensile tests.

  16. Evaluation of Shear Bond Strength of Methacrylate- and Silorane-based Composite Resin Bonded to Resin-Modified Glass-ionomer Containing Micro- and Nano-hydroxyapatite.

    Science.gov (United States)

    Sharafeddin, Farahnaz; Moradian, Marzie; Motamedi, Mehran

    2016-06-01

    The adhesion of resin-modified glass-ionomer (RMGI) to composite resin has a very important role in the durability of sandwich restorations. Hydroxyapatite is an excellent candidate as a filler material for improving the mechanical properties of glass ionomer cement. The aim of this study was to assess the effect of adding micro- and nano-hydroxyapatite (HA) powder to RMGI on the shear bond strength (SBS) of nanofilled and silorane-based composite resins bonded to RMGI containing micro- and nano-HA. Sixty cylindrical acrylic blocks containing a hole of 5.5×2.5 mm (diameter × height) were prepared and randomly divided into 6 groups as Group 1 with RMGI (Fuji II LC) plus Adper Single Bond/Z350 composite resin (5.5×3.5 mm diameter × height); Group 2 with RMGI containing 25 wt% of micro-HA plus Adper Single Bond/Z350 composite resin; Group3 with RMGI containing 25 wt% of nano-HA plus Adper Single Bond/Z350 composite resin; Group 4 with RMGI plus P90 System Adhesive/P90 Filtek composite resin (5.5×3.5 mm diameter × height); Group 5 with RMGI containing 25 wt% of micro-HA plus P90 System Adhesive/P90Filtek composite resin; and Group 6 with RMGI containing 25 wt% of nano-HA plus P90 System Adhesive/P90 Filtek composite resin. The specimens were stored in water (37° C, 1 week) and subjected to 1000 thermal cycles (5°C/55°C). SBS test was performed by using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed by two-way ANOVA and Tukey test (pcomposite resins. Meanwhile, RMGI without HA has the best bond strength to silorane-based composite resins.

  17. Transmission of composite polymerization contraction force through a flowable composite and a resin-modified glass ionomer cement.

    Science.gov (United States)

    Castañeda-Espinosa, Juan Carlos; Pereira, Rosana Aparecida; Cavalcanti, Ana Paula; Mondelli, Rafael Francisco Lia

    2007-12-01

    The purpose of this study was to evaluate the individual contraction force during polymerization of a composite resin (Z-250), a flowable composite (Filtek Flow, FF) and a resin-modified glass ionomer cement (Vitrebond, VB), and the transmission of Z-250 composite resin polymerization contraction force through different thicknesses of FF and VB. The experiment setup consisted of two identical parallel steel plates connected to a universal testing machine. One was fixed to a transversal base and the other to the equipment's cross head. The evaluated materials were inserted into a 1-mm space between the steel plates or between the inferior steel plate and a previously polymerized layer of an intermediate material (either FF or VB) adhered to the upper steel plate. The composite resin was light-cured with a halogen lamp with light intensity of 500 mW/cm(2) for 60 s. A force/time graph was obtained for each sample for up to 120 s. Seven groups of 10 specimens each were evaluated: G1: Z-250; G2: FF; G3: VB; G4: Z-250 through a 0.5-mm layer of FF; G5: Z-250 through a 1-mm layer of FF; G6: Z-250 through a 0.5-mm of VB; G7: Z-250 through a 1-mm layer of VB. They were averaged and compared using one-way ANOVA and Tukey test at a = 0.05. The obtained contraction forces were: G1: 6.3N + 0.2N; G2: 9.8 + 0.2N; G3: 1.8 + 0.2N; G4: 6.8N + 0.2N; G5: 6.9N + 0.3N; G6: 4.0N + 0.4N and G7: 2.8N + 0.4N. The use of VB as an intermediate layer promoted a significant decrease in polymerization contraction force values of the restorative system, regardless of material thickness. The use of FF as an intermediate layer promoted an increase in polymerization contraction force values with both material thicknesses.

  18. Transmission of composite polymerization contraction force through a flowable composite and a resin-modified glass ionomer cement

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    Juan Carlos Castañeda-Espinosa

    2007-12-01

    Full Text Available The purpose of this study was to evaluate the individual contraction force during polymerization of a composite resin (Z-250, a flowable composite (Filtek Flow, FF and a resin-modified glass ionomer cement (Vitrebond, VB, and the transmission of Z-250 composite resin polymerization contraction force through different thicknesses of FF and VB. The experiment setup consisted of two identical parallel steel plates connected to a universal testing machine. One was fixed to a transversal base and the other to the equipment's cross head. The evaluated materials were inserted into a 1-mm space between the steel plates or between the inferior steel plate and a previously polymerized layer of an intermediate material (either FF or VB adhered to the upper steel plate. The composite resin was light-cured with a halogen lamp with light intensity of 500 mW/cm² for 60 s. A force/time graph was obtained for each sample for up to 120 s. Seven groups of 10 specimens each were evaluated: G1: Z-250; G2: FF; G3: VB; G4: Z-250 through a 0.5-mm layer of FF; G5: Z-250 through a 1-mm layer of FF; G6: Z-250 through a 0.5-mm of VB; G7: Z-250 through a 1-mm layer of VB. They were averaged and compared using one-way ANOVA and Tukey test at a = 0.05. The obtained contraction forces were: G1: 6.3N + 0.2N; G2: 9.8 + 0.2N; G3: 1.8 + 0.2N; G4: 6.8N + 0.2N; G5: 6.9N + 0.3N; G6: 4.0N + 0.4N and G7: 2.8N + 0.4N. The use of VB as an intermediate layer promoted a significant decrease in polymerization contraction force values of the restorative system, regardless of material thickness. The use of FF as an intermediate layer promoted an increase in polymerization contraction force values with both material thicknesses.

  19. Shear bond strength evaluation of resin composite bonded to three different liners: TheraCal LC, Biodentine, and resin-modified glass ionomer cement using universal adhesive: An in vitro study

    OpenAIRE

    Deepa, Velagala L; Bhargavi Dhamaraju; Indira Priyadharsini Bollu; Tandri S Balaji

    2016-01-01

    Aims: To compare and evaluate the bonding ability of resin composite (RC) to three different liners: TheraCal LC TM (TLC), a novel resin-modified (RM) calcium silicate cement, Biodentine TM (BD), and resin-modified glass ionomer cement (RMGIC) using an universal silane-containing adhesive and characterizing their failure modes. Materials and Methods: Thirty extracted intact human molars with occlusal cavity (6-mm diameter and 2-mm height) were mounted in acrylic blocks and divided into th...

  20. In vitro fluoride release from a different kind of conventional and resin modified glass-ionomer cements.

    Science.gov (United States)

    Selimović-Dragaš, Mediha; Hasić-Branković, Lajla; Korać, Fehim; Đapo, Nermin; Huseinbegović, Amina; Kobašlija, Sedin; Lekić, Meliha; Hatibović-Kofman, Šahza

    2013-08-01

    Fluoride release is important characteristic of glass-ionomer cements. Quantity of fluoride ions released from the glass-ionomer cements has major importance in definition of their biological activity. The objectives of this study were to define the quantity of fluoride ions released from the experimental glass-ionomer cements and to define the effect of fluoride ions released from the experimental glass-ionomer cements on their cytotoxicity. Concentrations of the fluoride ions released in the evaluated glass-ionomer cements were measured indirectly, by the fluoride-selective WTW, F500 electrode potential, combined with reference R503/D electrode. Statistical analyses of F-ion concentrations released by all glass-ionomers evaluated at two time points, after 8 and after 24 hours, show statistically higher fluoride releases from RMGICs: Vitrebond, Fuji II LC and Fuji Plus, when compared to conventional glass-ionomer cements: Fuji Triage, Fuji IX GP Fast and Ketac Silver, both after 8 and after 24 hours. Correlation coefficient between concentrations of fluoride ion released by evaluated glass-ionomer cements and cytotoxic response of UMR-106 osteoblast cell-line are relatively high, but do not reach levels of biological significance. Correlation between concentrations of fluoride ion released and cytotoxic response of NIH3T3 mouse fibroblast cell line after 8 hours is high, positive and statistically significant for conventional GICs, Fuji Triage and Fuji IX GP Fast, and RMGIC, Fuji II LC. Statistically significant Correlation coefficient between concentrations of fluoride ion released and cytotoxic response of NIH3T3 cell line after 24 hours is defined for RMGIC Fuji II LC only.

  1. One year comparative clinical evaluation of EQUIA with resin-modified glass ionomer and a nanohybrid composite in noncarious cervical lesions

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    Deepa Sunil Vaid

    2015-01-01

    Full Text Available Aims: Comparative evaluation of EQUIA with a resin-modified glass ionomer cement (RMGIC; GC Gold Label glass ionomer light cured universal restorative cement and a nanohybrid composite (Tetric N-Ceram in noncarious cervical lesions (NCCLs. Background: To establish the most suitable material for the restoration of NCCLs. Settings and Design: In vivo study. Materials and Methods: Eighty-seven NCCLs were randomly restored with EQUIA, a RMGIC, and a nanohybrid composite. Clinical evaluation of the restorations was done following the Unites States Public Health criteria by a single-blinded investigator. Data were formulated, and statistical analysis was done by Chi-square test. Statistical Analysis Used: Chi-square test. Results: No significant difference was found between EQUIA, RMGIC, and nanohybrid composite at 1-month, at 6 months, and at 1-year (P > 0.05. Conclusions: EQUIA, resin-modified glass ionomer, and nanohybrid composite performed equally at 1-month, 6 months, and 1-year follow-up periods.

  2. Comparison of shear bond strength of resin-modified glass ionomer to conditioned and unconditioned mineral trioxide aggregate surface: An in vitro study

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    Shikha Gulati

    2014-01-01

    Full Text Available Introduction: The aim of this study was to compare the shear bond strength of resin modified glass ionomer cement to conditioned and unconditioned mineral trioxide aggregate surface. Materials and Method: White Mineral Trioxide Aggregate (WMTA and Resin Modified Glass Ionomer Cement (RMGIC were used for the study. 60 WMTA specimens were prepared and stored in an incubator at 37° C and 100% humidity for 72 hrs. The specimens were then divided into two groups- half of the specimens were conditioned and remaining half were left unconditioned, subsequent to which RMGIC was placed over MTA. The specimens were then stored in an incubator for 24 hrs at 37° C and 100% humidity. The shear bond strength value of RMGIC to conditioned and unconditioned WMTA was measured and compared using unpaired ′t  ′ test. Results: The mean shear bond strength of value of RMGIC to conditioned and unconditioned WMTA was 6.59 MPa and 7.587 MPa respectively. Statistical analysis using unpaired t-test revealed that the difference between values of two groups was not statistically significant (P > 0.05. Conclusions: During clinical procedures like pulp capping and furcal repair, if RMGIC is placed as a base over MTA, then conditioning should be done to increase the bond strength between RMGIC and dentin and any inadvertent contact of conditioner with MTA will not significantly affect the shear bond strength value of RMGIC to MTA.

  3. The effect of subject age on the microtensile bond strengths of a resin and a resin-modified glass ionomer adhesive to tooth structure.

    Science.gov (United States)

    Brackett, William W; Tay, Franklin R; Looney, Stephen W; Ito, Shuichi; Haisch, Larry D; Pashley, David H

    2008-01-01

    In this study, the microtensile bond strengths of an etch-and-rinse resin adhesive to dentin and enamel and a resin-modified glass ionomer adhesive to dentin were determined on teeth known to have originated from subjects over 60 years of age. The same tests were repeated on teeth originating from young subjects. The resin adhesive was Prime & Bond NT (Caulk/Dentsply), while the resin-modified glass ionomer adhesive was Fuji Bond LC (GC America). Both were paired with the same hybrid resin composite, TPH3 (Caulk/Dentsply). Testing was performed after 48 hours using a "non-trimming" microtensile test at a crosshead speed of 0.6 mm/minute. No significant differences were observed between the young and aged teeth for any comparison (p > 0.05). SEM evaluation of the etched dentinal surfaces demonstrated less depth of decalcification in the intertubular areas of aged dentin, but there was no observable difference within the tubules of young and aged dentin.

  4. A new self-curing resin-modified glass-ionomer cement for the direct bonding of orthodontic brackets in vivo.

    Science.gov (United States)

    Fricker, J P

    1998-04-01

    A new self-curing (chemically cured) resin-modified glass-ionomer cement, Fuji Ortho (GC International), is based on the technology of hybrid glass-ionomer restorative materials and features chemical adhesion to tooth structure and long-term fluoride release. This article describes a 12-month clinical evaluation of Fuji Ortho for the direct bonding of orthodontic (metal) brackets with System 1+ (Ormco Corp.) as a control. Three failures of Fuji Ortho occurred from a sample of 60 (5%), with five failures of the composite resin from a sample of 60 (8.3%). No statistical significance was seen between these results. Fuji Ortho is a satisfactory adhesive for the direct bonding of orthodontic brackets where there are no occlusal interferences.

  5. In vitro Evaluation of Stainless Steel Crowns cemented with Resin-modified Glass Ionomer and Two New Self-adhesive Resin Cements

    Science.gov (United States)

    Shashibhushan, KK; Poornima, P; Reddy, VV Subba

    2016-01-01

    Aims To assess and compare the retentive strength of two dual-polymerized self-adhesive resin cements (RelyX U200, 3M ESPE & SmartCem2, Dentsply Caulk) and a resin-modified glass ionomer cement (RMGIC; RelyX Luting 2, 3M ESPE) on stainless steel crown (SSC). Materials and methods Thirty extracted teeth were mounted on cold cured acrylic resin blocks exposing the crown till the cemento-enamel junction. Pretrimmed, precontoured SSC was selected for a particular tooth. Standardized tooth preparation for SSC was performed by single operator. The crowns were then luted with either RelyX U200 or SmartCem2 or RelyX Luting 2 cement. Retentive strength was tested using Instron universal testing machine. The retentive strength values were recorded and calculated by the formula: Load/Area. Statistical analysis One-way analysis of variance was used for multiple comparisons followed by post hoc Tukey’s test for groupwise comparisons. Unpaired t-test was used for intergroup comparisons. Results RelyX U200 showed significantly higher retentive strength than rest of the two cements (p 0.05). Conclusion The retentive strength of dual-polymerized self-adhesive resin cements was better than RMGIC, and RelyX U200 significantly improved crown retention when compared with SmartCem2 and RelyX Luting 2. How to cite this article Pathak S, Shashibhushan KK, Poornima P, Reddy VVS. In vitro Evaluation of Stainless Steel Crowns cemented with Resin-modified Glass Ionomer and Two New Self-adhesive Resin Cements. Int J Clin Pediatr Dent 2016;9(3):197-200. PMID:27843249

  6. A novel star-shaped poly(carboxylic acid) for resin-modified glass-ionomer restoratives.

    Science.gov (United States)

    Weng, Y; Howard, L; Xie, D

    2014-07-01

    We have developed a novel glass-ionomer cement (GIC) system composed of photo-curable star-shaped poly(acrylic acid-co-itaconic acid)s. These polyacids were synthesized via a chain-transfer radical polymerization using a newly synthesized multi-arm chain-transfer agent. The star-shaped polyacids showed significantly lower viscosities in water as compared to the linear polyacids. Due to the lower viscosities, the molecular weight (MW) of the polyacids can be significantly increased for enhancing the mechanical strengths while keeping the ease of mixing and handling. The effects of MW, GM-tethering ratio, P/L ratio, and aging on the compressive properties of the experimental cements were significant. The light-cured experimental cements showed significantly improved mechanical strengths i.e. 49% in yield strength, 41% in modulus, 25% in CS, 20% in DTS, and 36% in FS, higher than commercial Fuji II LC. After aging in water for 1 month, the compressive strength of the novel light-cured experimental cement reached 343 MPa, which was 34% and 42% higher than Fuji II and Fuji II LC, respectively. This one-month aged experimental cement was also 23% higher than itself after one day aging, indicating that aging in water can significantly enhance salt-bridge formation for this novel star-shaped polyacid-comprised GIC.

  7. Fracture frequency and longevity of fractured resin composite, polyacid-modified resin composite, and resin-modified glass ionomer cement class IV restorations: an up to 14 years of follow-up

    DEFF Research Database (Denmark)

    van Dijken, Jan W V; Pallesen, Ulla

    2010-01-01

    The aim of this study was to evaluate the fracture frequency and longevity of fractured class IV resin composite (RC), polyacid-modified resin composite (compomer; PMRC), and resin-modified glass ionomer cement (RMGIC) restorations in a longitudinal long-term follow-up. Eighty-five class IV RC (43...

  8. Evaluation of the effect of adding micro-hydroxyapatite and nano-hydroxyapatite on the microleakage of conventional and resin-modified Glass-ionomer Cl V restorations

    Science.gov (United States)

    Sharafeddin, Farahnaz

    2017-01-01

    Background Pulpal reaction to restorative materials depends on marginal microleakage, which is a dynamic phenomenon that allows bacteria and fluids to traverse across the tooth-restoration interface. Glass-ionomer cement (GIC) exhibits low microleakage due to direct bonding to tooth structures. Hydroxyapatite (HAP) based on the similarity with tooth structure may decrease the microleakage. The aim of this in vitro study was to evaluate marginal microleakage of a mixture of conventional and resin-modified glass-ionomer (RMGI) with micro- and nano-HAP. Material and Methods In this in vitro study, 30 non-carious extracted human third molar teeth were used. Standard Cl V cavities were prepared on the buccal and lingual surfaces. The cavities were restored in six experimental groups as follows: group 1, conventional glass-ionomer cement (CGIC); group 2, CGIC with micro-HAP; group 3, CGIC with nano-HAP; group 4, RMGI; group 5, RMGI with micro-HAP; group 6, RMGI with nano-HAP. The restorations were finished and polished. The teeth were coated with nail polish, sealed with sticky wax, thermocycled and placed in a solution of 2% basic fuchsine for 24 hours. The teeth were sectioned and microleakage was measured. Kruskal-Wallis, Man-Whitney and Wilcoxon tests were used for data analysis (PGlass-ionomer, micro-hydroxyapatite, microleakage, nano-hydroxyapatite. PMID:28210443

  9. Retention of oral microorganisms on conventional and resin-modified glass-ionomer cements Retenção de microrganismos bucais em cimentos de ionômero de vidro convencionais e modificados por resina

    Directory of Open Access Journals (Sweden)

    Denise PEDRINI

    2001-09-01

    Full Text Available Secondary caries are a worldwide public and socioeconomic problem. The placement of restorations can lead to the development of environmental conditions favorable to microbial colonization, especially on the tooth/restoration interface, which is a predisposing factor for secondary caries. The aim of this study was to evaluate microbial retention on conventional (Chelon-Fil and Vidrion R and resin-modified (Vitremer and Fuji II LC glass-ionomer cements, in situ, using a hybrid composite resin (Z100 as a control. Twelve volunteers wore Hawley appliances with specimens made of all tested filling materials for 7 days. The specimens were then removed from the appliances and transferred to tubes containing 2.0 ml of Ringer-PRAS. Microorganisms from the samples were inoculated onto blood agar and Mitis Salivarius Bacitracin agar and incubated under anaerobiosis (90% N2, 10% CO2, at 37°C, for 10 and 2 days, respectively. The resin-modified glass-ionomer cements and the composite resin retained the same levels of microorganisms on their surfaces. The resin-modified glass-ionomers retained less mutans streptococci than the composite resin and conventional glass-ionomer cements. The conventional glass-ionomer cements retained less mutans streptococci than the composite resin, but that difference was not statistically significant.A cárie secundária representa problema de saúde pública e socioeconômico no mundo. A restauração de dentes acometidos por cárie pode criar condições favoráveis à proliferação microbiana na superfície do material restaurador ou na interface dente/restauração, criando ambiente propício para o estabelecimento de cárie secundária. O objetivo deste estudo foi avaliar a capacidade de retenção de placa bacteriana em cimentos de ionômero de vidro convencionais (Chelon-Fil e Vidrion R e modificados por resina (Vitremer e Fuji II LC e de resina composta híbrida (Z100, utilizada como controle. Nos testes de reten

  10. Effect of light-cure initiation time on polymerization and orthodontic bond strength with a resin-modified glass-ionomer

    Science.gov (United States)

    Thomas, Jess

    Introduction: The polymerization and acid-base reactions in resin-modified glass-ionomers (RMGI) are thought to compete with and inhibit one another. The objective of this study was to examine the effect of visible light-cure (VLC) delay on the polymerization efficiency and orthodontic bond strength of a dual-cured RMGI. Methods: An RMGI light-cured immediately, 2.5, 5, or 10 minutes after mixing comprised the experimental groups. Isothermal and dynamic temperature scan differential scanning calorimetry (DSC) analysis of the RMGI was performed to determine extents of VLC polymerization and acid-base reaction exotherms. Human premolars (n = 18/group) were bonded with the RMGI. Shear bond strength and adhesive remnant index (ARI) scores were determined. Results: DSC results showed the 10 minute delay RMGI group experienced significantly (P 0.05) were noted among the groups for mean shear bond strength. A chi-square test showed no significant difference (P = 0.428) in ARI scores between groups. Conclusions: Delay in light-curing may reduce polymerization efficiency and alter the structure of the RMGI, but orthodontic shear bond strength does not appear to be compromised.

  11. Clinical study of the caries-preventive effect of resin-modified glass ionomer restorations: aging versus the influence of fluoride dentifrice.

    Science.gov (United States)

    de Moraes, Maria Denise Rodrigues; de Melo, Mary Anne Sampaio; Bezerra, Daniela da Silva; Costa, Luciana Scarlazzari; Saboía, Vicente de Paula Aragão; Rodrigues, Lidiany Karla Azevedo

    2016-05-01

    The use of fluoride-releasing materials could be compromised due to aging and might also be influenced by other ordinary sources of fluoride. The aim of the present study was to investigate the aging effect on caries development around resin-modified glass ionomer cement (RMGIC) restorations and the influence of fluoride dentifrice use in this process under the oral environment. A clinical study was performed in two phases of 14 days each. A total of 16 volunteers wore palatal devices containing dental slabs restored with either a composite resin or RMGIC, either aged or unaged by thermocycling. To simulate a clinical situation of high caries risk, the slabs were exposed to a 20% sucrose solution 10 times per day via the in situ model, where non-fluoride or a fluoride dentifrice was used. Integrated demineralization was determined by cross-sectional microhardness at both margins of the restoration: enamel and dentin. For enamel, higher demineralization around the composite restorations was observed, regardless of dentifrice or aging. For dentin, higher demineralization was observed around the aged composite restorations regardless of the dentifrice type used. The RMGIC restorations provided more enhanced protection against secondary caries for dentin under aging, and the fluoride dentifrice used in this condition had either no clinically relevance or only a minimal effect. © 2015 Wiley Publishing Asia Pty Ltd.

  12. Clinical performance of a resin-modified glass-ionomer and two polyacid-modified resin composites in cervical lesions restorations: 1-year follow-up.

    Science.gov (United States)

    Chinelatti, M A; Ramos, R P; Chimello, D T; Palma-Dibb, R G

    2004-03-01

    The aim of this study was to assess the clinical performance of a resin-modified glass-ionomer cement (Vitremer) and two polyacid-modified resin composites (F2000 and Freedom) over 1 year. Nineteen patients with at least three cervical lesions were selected, providing an initial sample size of 87 restorations (29 per material), being 78 to non-carious and nine to carious lesions. Restorations were evaluated at baseline, 6 months and 1 year after placement, using modified US Public Health Service criteria: colour match, marginal discoloration, caries, anatomical form, marginal integrity and surface texture. At baseline, restorations were considered as acceptable for all criteria. At 1-year recall, 21 restorations per material were re-examined. Freedom was rated Bravo or Charlie for all the examined criteria and Vitremer earned an Alfa rating solely for the criterion caries. On the contrary, F2000 showed the best overall results, although presenting significant alteration in colour match. Statistical analysis of data was performed using chi-square and Mc Nemar tests. As to the evaluated periods, significant difference was observed solely between baseline and 1-year recall. Freedom and Vitremer were statistically different (P < 0.01) as to anatomical form and surface texture. For F2000, significant difference (P < 0.05) was noticed as to colour match and anatomical form. After 1-year follow-up, F2000 showed the most acceptable results as to the analysed criteria.

  13. Effect of resin-modified glass-ionomer cement lining and composite layering technique on the adhesive interface of lateral wall

    Directory of Open Access Journals (Sweden)

    Larissa Marinho AZEVEDO

    2015-06-01

    Full Text Available Interface integrity can be maintained by setting the composite in a layering technique and using liners. Objective The aim of this in vitro study was to verify the effect of resin-modified glass-ionomer cement (RMGIC lining and composite layering technique on the bond strength of the dentin/resin adhesive interface of lateral walls of occlusal restorations. Material and Methods Occlusal cavities were prepared in 52 extracted sound human molars, randomly assigned into 4 groups: Group 2H (control – no lining + two horizontal layers; Group 4O: no lining + four oblique layers; Group V-2H: RMGIC lining (Vitrebond + two horizontal layers; and Group V-4O: RMGIC lining (Vitrebond + four oblique layers. Resin composite (Filtek Z250, 3M ESPE was placed after application of an adhesive system (Adper™ Single Bond 2, 3M ESPE dyed with a fluorescent reagent (Rhodamine B to allow confocal microscopy analysis. The teeth were stored in deionized water at 37oC for 24 hours before being sectioned into 0.8 mm slices. One slice of each tooth was randomly selected for Confocal Laser Scanning Microscopy (CLSM analysis. The other slices were sectioned into 0.8 mm x 0.8 mm sticks to microtensile bond strength test (MPa. Data were analyzed by two-way ANOVA and Fisher's test. Results There was no statistical difference on bond strength among groups (p>0.05. CLSM analysis showed no significant statistical difference regarding the presence of gap at the interface dentin/resin among groups. Conclusions RMGIC lining and composite layering techniques showed no effect on the microtensile bond strength and gap formation at the adhesive interface of lateral walls of high C-factor occlusal restorations.

  14. A new atraumatic method of removing fractured palatal root using endodontic H-files luted with resin modified glass ionomercement: A pilot study

    Directory of Open Access Journals (Sweden)

    V Sadesh Kannan

    2014-01-01

    Full Text Available Purpose: The purpose of this study is to evaluate the efficacy of using endodontic H-files luted with Resin modified glass ionomer cement (RMGIC in removing fractured palatal root. Materials and Methods: This study consists of 30 patients, of which 16 were males and 14 were females with a mean age of 36 years. In which, 19 were maxillary first molar and 11 were maxillary second molar. In that, 18 were fractured at the level of apical 1/3 rd and 12 were at the level of apical 2/3 rd . All cases were first tried with endodontic H-files, within few attempts, it was wedged tightly in the remaining pulp chamber with one or two clockwise direction and using sudden jerk with a downward pull the remnant part was removed. The cases, which fail to deliver after several attempts were taken up for study. After sufficient isolation with a rubber dam and the socket was dried using sterile gauze, under good lighting and vision again the same file was introduced, which was now luted with RMGIC, after 5 min of setting time, the same attempt using sudden jerk with a downward pull was given. Results: In those 30 cases, 20 cases were removed in the first few attempts using endodontic H-files. The 10 cases (7 cases were apical 2/3 rd and 3 cases were of apical 1/3 rd , which fails to come out were tried using endodontic H-files luted with RMGIC, in which 9 cases were successfully removed (90% and 1 case of apical 1/3 rd was again failed to come out. Conclusion: Even though, the number of cases were too small to come to a definitive conclusion, the encouraging result (90% and technically easy, this is a novel method of removing fractured palatal root atraumatically and devoid of any complication.

  15. Selective separation of mercury(II) using magnetic chitosan resin modified with Schiff's base derived from thiourea and glutaraldehyde.

    Science.gov (United States)

    Donia, Ahmed M; Atia, Asem A; Elwakeel, Khalid Z

    2008-03-01

    Magnetic chitosan resin was chemically modified by a Schiff's base cross-linker. The interaction of the resin obtained with Hg(II) was studied and uptake value of 2.8 mmol/g was reported. The kinetic and thermodynamic parameters of the adsorption process were estimated. These data indicated that the adsorption process is exothermic and follow the pseudo-second-order kinetics. The selectivity of Hg(II) from other different metal ions in solutions using the studied resin was also reported. Breakthrough curves for the recovery of Hg(II) were studied. The critical bed height was found to be 2.05 cm. The adsorbed Hg(II) was eluted from the resin effectively using 0.1 M potassium iodide.

  16. Microleakage of class V cavities restored with nanofilled resin modified glass ionomer and conventional glass ionomer with self etch adhesive and self etch primer

    Directory of Open Access Journals (Sweden)

    Mansore Mirzaie

    2016-03-01

    Full Text Available Background and Aims: Microleakage is a criterion proposed for assessing the success of any restorative material. Complete seal is difficult especially for dentin margins compared to enamel margins. The aim of this study was to assess the microleakage at the enamel and dentin margins of class V cavities restored by two GIs and two self-etch adhesive systems. Materials and Methods: This study was done on forty third molars. Class V cavities (3×2×2mm were prepared on the buccal and lingual surfaces of teeth using high speed handpiece with 0.8 mm diamond fissure burr. The occlusal margins of the cavities in the enamel and gingival marginswere placed 1 mm below the CEJ. The teeth were divided into 4 groups and the bondings were cured for 20 sec and the teeth were restored. The specimens were kept in distilled water at the temperature of 37°C for 24 hrs. The teeth were thermo cycled and cut in buccolingual direction using diamond disc under water. The dye penetration was evaluated using a stereomicroscope and the leakage was scored. The scores were compared using Kruskal-Wallis test while the paired comparisons were done using Bonferroni correction. P≤0.05 was regarded as significant results. Results: Microleakage scores were similar at the occlusal and gingival walls of all test groups. At the gingival walls, the least microleakage scores were observed. “Fuji IX + SE bond” group showed significant differences with the “Fuji IX + G bond” and “Nanoglass + G bond” groups (P≤0.05. At the occlusal walls, the least scores were observed in the “Fuji IX+SE bond” specimens which were significantly different from the other groups (P≤0.05. Conclusion: Self-Cure glass ionomers yielded less microleakage scores compared to the different types of light-cures due to the less polymerization shrinkage.

  17. Shear bond strength evaluation of resin composite bonded to three different liners: TheraCal LC, Biodentine, and resin-modified glass ionomer cement using universal adhesive: An in vitro study

    Directory of Open Access Journals (Sweden)

    Velagala L Deepa

    2016-01-01

    Full Text Available Aims: To compare and evaluate the bonding ability of resin composite (RC to three different liners: TheraCal LC TM (TLC, a novel resin-modified (RM calcium silicate cement, Biodentine TM (BD, and resin-modified glass ionomer cement (RMGIC using an universal silane-containing adhesive and characterizing their failure modes. Materials and Methods: Thirty extracted intact human molars with occlusal cavity (6-mm diameter and 2-mm height were mounted in acrylic blocks and divided into three groups of 10 samples each based on the liner used as Group A (TLC, Group B (BD, and Group C (RMGIC. Composite post of 3 mm diameter and 3 mm height was then bonded to each sample using universal adhesive. Shear bond strength (SBS analysis was performed at a cross-head speed of 1 mm/min. Statistical Analysis Used: Statistical analysis was performed with one-way analysis of variance (ANOVA and post hoc test using Statistical Package for the Social Sciences (SPSS version 20. Results: No significant difference was observed between group A and group C (P = 0.573 while group B showed the least bond strength values with a highly significant difference (P = 0.000. The modes of failure were predominantly cohesive in Groups A and B (TLC and BD while RMGIC showed mixed and adhesive failures. Conclusions: Hence, this present study concludes that the bond strength of composite resin to TLC and RMGIC was similar and significantly higher than that of BD following application of universal adhesive.

  18. Effect of Ascorbic Acid on Shear Bond Strength of Orthodontic Brackets Bonded with Resin-modified Glass-ionomer Cement to Bleached Teeth

    Directory of Open Access Journals (Sweden)

    Behnam Khosravanifard

    2012-04-01

    Full Text Available Background and aims. Bleaching can considerably reduce shear bond strength (SBS of orthodontic brackets bonded with composite adhesives. Application of antioxidants is a method to reverse the negative effect of bleaching on compositeto-enamel bond. However, the efficacy of antioxidants in increasing the SBS of brackets bonded using resin-modified glassionomer cement (RMGIC has not been studied, which was the aim of this study. Materials and methods. Fifty freshly extracted human maxillary first premolars were bleached with 35% hydrogen peroxide (Pola Office Bleaching, SDI. Sodium ascorbate 10% was applied to the experimental specimens (n=25. All the specimens were etched with 37% phosphoric acid (Ivoclar/Vivadent and bonded using RMGIC (Fuji Ortho LC, GC. The specimens were subjected to incubation (37°C, 24h and thermocycling (1000 cycles, 5-55°C, dwell time = 1 min. The SBS was measured at 0.5 mm/min debonding crosshead speed. The adhesive remnant index (ARI was scored under ×10 magnification. Data were analyzed using Mann-Whitney U test, one- and independent-samples t-test, and Fisher’s exact test (α=0.05. Results. The mean SBS of experimental and control groups were 11.97 ± 4.49 and 7.7 ± 3.19 MPa, respectively. The difference was statistically significant (P=0.000 by t-test. SBS of both control (P=0.014 and experimental (P=0.000 groups were significantly higher than the minimum acceptable SBS of 6 MPa, according to one-sample t-test. Conclusion. Application of ascorbic acid can guarantee a strong bond when RMGIC is to be used. However, RMGIC might tolerate the negative effect of bleaching with minimum SA treatments (or perhaps without treatments, which deserves further studies.

  19. Streptococcus mutans counts in plaque adjacent to orthodontic brackets bonded with resin-modified glass ionomer cement or resin-based composite

    Directory of Open Access Journals (Sweden)

    Solange Machado Mota

    2008-03-01

    Full Text Available This study investigated the number of Streptococcus mutans CFU (colony forming units in the saliva and plaque adjacent to orthodontic brackets bonded with a glass ionomer cement - GIC (Fuji Ortho or a resin-based composite - RC (Concise. Twenty male and female patients, aged 12 to 20 years, participated in the study. Saliva was collected before and after placement of appliances. Plaque was collected from areas adjacent to brackets and saliva was again collected on the 15th, 30th, and 45th day after placement. On the 30th day, 0.4% stannous fluoride gel was applied for 4 minutes. No significant modification in the number of Streptococcus mutans CFU in saliva was observed after placement of the fixed orthodontic appliances. On the 15th day, the percentage of Streptococcus mutans CFU in plaque was statistically lower in sites adjacent to GIC-bonded brackets (mean = 0.365 than in those adjacent to RC-bonded brackets (mean = 0.935. No evidence was found of a contribution of GIC to the reduction of CFU in plaque after the 15th day. Topical application of stannous fluoride gel on the 30th day reduced the number of CFU in saliva, but not in plaque. This study suggests that the antimicrobial activity of GIC occurs only in the initial phase and is not responsible for a long-term anticariogenic property.

  20. Microleakage of Resin- Modified Glass Ionomer Cement and Compomer Restorations in vitro%改良型玻璃离子水门汀及复合体的边缘微漏研究

    Institute of Scientific and Technical Information of China (English)

    陆忆; 丁玲; 陆群

    2001-01-01

    目的比较两种树脂改良型玻璃离子水门汀及两种树脂复合体边缘封闭性。方法选用40颗成人离体恒磨牙,制备V类洞型,分别用两种树脂改良型光固化玻璃离子水门汀(GCFujiⅡLC和Vitremer TM)及两种多元酸修饰的树脂复合体(Dyract复合体和F2000复合体)充填,经冷热交替试验(5~55℃,循环20次),采用1%碱性品红染料渗入法观察充填体与牙体洞壁间边缘微漏。结果在V类洞壁及龈壁4种不同材料的边缘封闭性存在显著差异(P=0.026,P=0.000),壁侧GC FGCiⅡLC组显著优于其它各组,龈壁侧Dyract复合体组显著比其它各组差。结论牙面的不同处理及充填材料的聚合收缩、吸水率以及热膨胀系数的差异等都是影响微漏的因素。树脂改良型光固化玻璃离子水门汀边缘封闭性优于树脂复合体。%Objective To evaluate the marginal integrity of restoration in two types of mate- rials, or resin- modified glass ionomer cement and polyacid- modified composite resin (compomer). Methods Restorations of four kinds of material (GC Fuji Ⅱ LC, VitremerTM, Dyract compomer and F2000 compomer) were placed in the facial Class V cavity preparations in forty noncarious human molar teeth. The teeth were randomly assigned to 4 experimental groups of 10 teeth each. After thermal cy- cling( × 20,5 ~55℃ ), the teeth were immersed in 1% basic fuchsin dye for 24 hours at room tempera- ture. Staining along the teeth restoration interface was recorded. Results The data indicated signifi- cant differences between all the restorative materials for both occlusal and gingival scores ( P=0.026, P = 0. 000)respectively. Further analysis revealed there were statistically significant differences between GC Fuji Ⅱ LC and others on occlusal margins versus Dyract compomer and others on gingival margins. Conclusion Factors such as dental conditioning, rates of water absorption and thermal coefficient were related to

  1. Application of light-cure resin-modified glass ionomer cement in orthodontic practice%光固化树脂加强型玻璃离子水门汀在正牙学实践中的作用

    Institute of Scientific and Technical Information of China (English)

    单丽华; 崔占琴; 沈庆华; 高琪; 邱志香

    2008-01-01

    BACKGROUND: Resin-modified glass ionomer (RMGI) cements have higher bond strength, especially can release fluoride. But there are fewer reports of the clinical application for the prevention of decalcification.OBJECTIVE: To test the benefit from using RMGI cement instead of a conventional composite resin in bracket bonding for patients with malocclusion, and observe bracket-failure rates and decalcification on enamel surfaces at pretreatment and at debonding.DESIGN: Observational and comparative trial.SETTING: The Second Hospital Affiliated to Hebei Medical University.PARTICIPANTS: Forty successive patients (358 teeth) with malocclusion admitted to the Department of Orthodontics in the Second Hospital Affiliated to Hebei Medical University, were selected for the study from July to August in 2002. All the patients (21 females and 19 males, mean age 16 years) had normal and complete anterior teeth, good oral hygiene. There were no obvious differences in bilateral teeth. Informed consents were obtained from all the subjects. The experiment was also approved by the ethical committee of the hospital. Experimental materials were RMGI adhesive (Fuji, GC, Japan, Lot 0005111) and composite resin cement (enamel adhesive of Beijing and Tianjin, Tianjin product, Lot 020402). Brackets produced from Hangzhou 3B and 37% phosphoric acid were used.METHODS: ①Bonding brackets: Subjects selected according to random procedure were divided into two groups, each with 20. GroupⅠ: The left buccal surfaces bonded with light-cure RMGI were etching for 30 seconds with 37% phosphoric acid, rinsed with water; the right buccal surfaces bonded with composite resin cement were etching for 60 seconds with 37% phosphoric acid, rinsed with water and dried; Group Ⅱ: After etching for 30 seconds with 37% phosphoric acid, the right buccal surfaces were rinsed with water and bonded brackets with light-cure RMGI. The left buccal surfaces were bonded brackets with composite resin cement after etching

  2. 树脂加强型玻璃离子结合不同牙面酸蚀方法对托槽粘接效果的影响%Effects of different management combined with resin-modified glass ionomer on orthodontic brackets bonded to tooth enamel

    Institute of Scientific and Technical Information of China (English)

    徐小兵

    2011-01-01

    目的:观察比较自酸蚀和全酸蚀处理牙面时,树脂加强型玻璃离子粘接剂粘接托槽的临床效果.方法:随机选择牙列完整的40例非拔牙固定正畸矫治患者的上颌患牙400颗,分为实验组:自酸蚀封闭剂(self-etching primer,3M 公司)配合树脂加强型玻璃离子粘固剂(resin-modified glass ionomer cement,RMGIC);对照组:37%磷酸配合加强型玻璃离子粘固剂粘接托槽,观察比较正畸治疗期间两组患者MBT托槽的脱落情况.结果:树脂加强型玻璃离子结合使用自酸蚀与传统的酸蚀方法粘接MBT托槽的脱落率比较,差异无统计学意义(P>0.05).结论:①全酸蚀配合树脂加强型玻璃离子正畸粘接剂的粘接强度更好;②RMGIC作为一种新型的正畸粘接材料,结合了传统玻璃离子和复合树脂的优点,具有临床操作可控性强、MBT托槽准确率较高的优点,满足了临床需求,可以选择应用.%Objective: To observe and compare the effects of different management combined with resin-modified glass ionomer on orthodontic brackets bonded to tooth enamel by self-etching primer (SEP) or totaletching adhesives. Methods: 400 maxillary teeth from 40 patients free of teeth extracted when receiving fixed orthodontic treatment were recruited and randomly allocated to groups of treatment and controls. The treatment group received management of SEP with resin-modified glass ionomer cement(RMGIC) and the controls were dealt with 37% phosphoric acid plus reinforced glass ionomer cement for comparison of the MBT bracket bonding failure. Results: No statistical difference was found between the two groups( P > 0.05 ). Conclusion: Total-etching adhesives with SEP might produce better bracket bonding effects on the tooth enamel, and yet, RMGIC, a new orthodontic material, if combined with SEP, could also be favorable to clinical use for its adequate strength exerted by MBT bracket bonding.

  3. Effect of one-bottle adhesive systems on the fluoride release of a resin-modified glass ionomer Efeito dos sistemas adesivos de frasco único na liberação de flúor de um cimento de ionômero de vidro modificado por resina

    Directory of Open Access Journals (Sweden)

    Linda Wang

    2004-03-01

    Full Text Available A dhesive systems associated to resin-modified glass ionomer cements are employed for the achievement of a higher bond strength to dentin. Despite this benefit, other properties should not be damaged. This study aimed at evaluating the short-time fluoride release of a resin-modified glass ionomer cement coated with two one-bottle adhesive systems in a pH cycling system. Four combinations were investigated: G1: Vitremer (V; G2: Vitremer + Primer (VP; G3: Vitremer + Single Bond (VSB and G4: Vitremer + Prime & Bond 2.1 (VPB. SB is a fluoride-free and PB is a fluoride-containing system. After preparation of the Vitremer specimens, two coats of the selected adhesive system were carefully applied and light-cured. Specimens were immersed in demineralizing solution for 6 hours followed by immersion in remineralizing solution for 18 hours, totalizing the 15-day cycle. All groups released fluoride in a similar pattern, with a greater release in the beginning and decreasing with time. VP showed the greatest fluoride release, followed by V, with no statistical difference. VSB and VPB released less fluoride compared to V and VP, with statistical difference. Regardless the one-bottle adhesive system, application of coating decreased the fluoride release from the resin-modified glass ionomer cements. This suggests that this combination would reduce the beneficial effect of the restorative material to the walls around the restoration.Sistemas adesivos são associados aos cimentos de ionômero de vidro modificados por resina para a obtenção de maior resistência adesiva à dentina. Apesar deste benefício, outras propriedades não devem ser prejudicadas. Este estudo se propôs a avaliar a liberação de flúor a curto prazo de um cimento de ionômero de vidro modificado por resina coberto com dois diferentes sistemas adesivos em um modelo de ciclagem de pH. Quatro associações foram testadas: G1: Vitremer (V; G2: Vitremer + Primer (VP; G3: Vitremer + Single

  4. Antibacterial Effects and Physical Properties of Resin-modified Glass-ionomer Cements Containing Minocycline%米诺环素对树脂改良型玻璃离子水门汀抗菌性能和机械性能的影响

    Institute of Scientific and Technical Information of China (English)

    陈春桂

    2012-01-01

    目的:研究添加不同浓度米诺环素对树脂改良型玻璃离子水门汀(resin-modified glass ionomer cement,RMGIC)抗菌性能和机械性能的影响.方法:将米诺环素以不同浓度加入RMGIC中,通过生物膜实验观察材料的抗菌性能;测量材料抗压缩强度及表面微硬度,评价添加抗菌剂对材料机械性能的影响.结果:生物膜形成实验结果显示添加米诺环素后能够有效提高RMGIC的抗菌性能,且抗菌性能的强弱与添加米诺环素的浓度成正比.加入较高浓度的米诺环素后,材料的抗压缩强度和表面微硬度降低.结论:米诺环素能有效增强RMGIC抑制变形链球菌的作用,但高浓度的米诺环素可使材料的机械性能受到影响.在对牙科充填材料进行抗菌改性的同时应当考虑材料本身的机械性能,选择合适的方法和浓度,以使材料发挥更好的作用.%Objective: To evaluate the antibacterial effects and physical properties of resin-modified glass - iono mer cements (RMGICs) containing minocycline. Methods: RMGIC (Fuji Ⅱ LC) was used as control. Minocycline was added to powdered RMGIC to obtain concentration ratios of 1. 5, 3. 0 and 4. 5% w/w. The antibacterial activity of each RMGIC was evaluated against Streptococcus mutans using biofilm assay. The compressive strength and mi-crohardness were measured and compared with those of control samples. Results: All experimental groups showed a significantly greater inhibition with growth of the selected bacteria in comparison to the control groups (P<0. 05). However, RMGIC with high concentration minocycline had significantly lower compressive strength and microhard-ness than the control group (P<0. 05). Conclusion: The minocycline-containing RMGIC were effective in inhibiting S. Mutans. However, high concentration minocycline compromised the mechanical properties of the cement.

  5. Synchrotron Radiation Investigation in Epoxy Resin Modified with Polysiloxane System

    Science.gov (United States)

    Gan, Wenjun; Li, Weizhen; Ding, Jindian; Gu, Xiaodan; Wang, Cheng

    2014-03-01

    Epoxy resins are one of the most important classes of thermosetting polymers. Epoxy resin modified with polysiloxane is expected that the siloxane moiety may exert its qualities of thermal stability, impact toughness and surface-modification properties. Our group tried to introduce polysiloxane into epoxy resin by blending diglycidyl-ether of bisphenol-A with epoxypropoxypropyl terminated polydimethyl-siloxane and polyetherimide-siloxane in different proportion. These polysiloxane modified epoxy resins have been investigated using a combination of small- and wide angle X-ray scatterings (SAXS and WAXS) and scanning transmission soft X-ray microscopy (STXM). Nano- to micro-scale domain size, distribution and chemical composition were observed with spatial and spectroscopic sensitivities offered by both hard and soft x-ray scattering/microscopy. In-situ SAXS experiments were performed to understand the mechanism of microphase separation and dynamics of nanostructure evolution. Acknowledgment: The authors thank Shanghai Municipal Education Commission (Overseas Visiting Scholar Program 2012) and Shanghai University of Engineering Science (2011xz04) for financial supports.

  6. Marginal Adaptation Evaluation of Biodentine and MTA Plus in "Open Sandwich" Class II Restorations.

    Science.gov (United States)

    Aggarwal, Vivek; Singla, Mamta; Yadav, Suman; Yadav, Harish; Ragini

    2015-01-01

    This study aimed at evaluation of two different commercially available calcium silicate materials (Biodentine and mineral trioxide aggregate [MTA] Plus) used as dentin substitute. Sixty Class II cavities were prepared in extracted mandibular third molars, with margins extending 1 mm below the cementum-enamel junction. The samples were divided into three groups on the basis of dentin substitute used: resin modified glass ionomer cement, Biodentine, and MTA Plus. Cavities were restored with composite resins in an "open sandwich" technique. The samples were subjected to alternate aging in phosphate buffered saline and cyclic loading. Marginal adaptation was evaluated in terms of "continuous margin" at the gingival margin, using a low vacuum scanning electron microscope. Statistical analysis was done with two-way analysis of variance with Holm-Sidak's correction for multiple comparisons. The glass ionomer group and Biodentine group presented an overall 83% and 91% of continuous margins, with no difference between them. MTA Plus showed least values of continuous margins. Granular deposits were seen over the surface of Biodentine and MTA Plus. Biodentine and resin-modified glass ionomer cement, when used as a dentin substitute under composite restorations in open sandwich technique, gave satisfactory marginal adaptation values. Contemporary calcium silicate materials can be used as dentin substitute materials in "open sandwich" Class II restorations. This study evaluates the marginal adaptation of Biodentine, MTA Plus, and resin modified glass ionomer cement used as dentin substitutes and reports better adaptation obtained with Biodentine and glass ionomer cement. © 2015 Wiley Periodicals, Inc.

  7. Physical Property Investigation of Contemporary Glass lonomer and Resin Modified Glass lonomer Restorative Materials

    Science.gov (United States)

    2016-05-24

    fracture toughness. vi Manuscript Introduction The optimal dental restorative material would be biocompatible, demonstrate adhesion to tooth material...10 GICs are self- adhesive materials that bond to tooth hard tissues through chemica l bonding to dental hard tissues, 11 as the ionic bond between...Colonel Michael N. Wajdowi Dean, Air Fo rce Postgraduate Dental School Acknowledgements Special thanks to Col Howard Roberts, Col Michael Wajdowicz

  8. Bioactive glass-ionomer cement with potential therapeutic function to dentin capping mineralization.

    Science.gov (United States)

    Xie, Dong; Zhao, Jun; Weng, Yiming; Park, Jong-Gu; Jiang, Hui; Platt, Jeffrey A

    2008-10-01

    We have developed a novel bioactive resin-modified glass-ionomer cement system with therapeutic function to dentin capping mineralization. In the system, the newly synthesized star-shape poly(acrylic acid) was formulated with water, Fuji II LC filler, and bioactive glass S53P4 to form resin-modified glass-ionomer cement. Compressive strength (CS) was used as a screening tool for evaluation. The commercial glass-ionomer cement Fuji II LC was used as a control. All the specimens were conditioned in simulated body fluid (SBF) at 37 degrees C prior to testing. The effect of aging in SBF on CS and microhardness of the cements was investigated. Scanning electron microscopy was used to examine the in vitro dentin surface changes caused by the incorporation of bioactive glass. The results show that the system not only provided strengths comparable to original commercial Fuji II LC cement but also allowed the cement to help mineralize the dentin in the presence of SBF. It appears that this bioactive glass-ionomer cement system has direct therapeutic impact on dental restorations that require root surface fillings.

  9. Design, Construction and Performance of Resin Modified Pavement at Fort Campbell Army Airfield, Kentucky

    Science.gov (United States)

    1994-03-01

    exposed aggregate surface when cured. Underfilling the surface voids is better than overfilling the surface voids . k- Excessive handwork with the... voids ......... 33 Figure 22. Close-up of air bubbles after vibration ................ 34 Figure 23. Removing excess slurry grout from surface...containing 25 to 35 percent voids which are filled with a resin modified cement slurry grout. A typical cross-section view of an RMP specimen is shown in

  10. Bond Strength of Silorane- and Methacrylate-Based Composites to Resin-Modified Glass Ionomers

    Science.gov (United States)

    2012-01-13

    showed the vast majority of recurrent caries occur at the gingival 3 margins, and suggests the need for a better bond at the dentinal/restoration...Mine et al., 2010). Yaman et al. (2010) examined premolars marked for extraction due to orthodontics , bonded either Filtek Supreme XT with Adper

  11. PHASE STRUCTURE AND PROPERTIES OF EPOXY RESIN MODIFIED BY POLYSILOXANE BEARING PENDANT AMINO GROUPS

    Institute of Scientific and Technical Information of China (English)

    Bing Zhang; Xiang-luan Liu; Ying Huang

    2000-01-01

    Polysiloxane-modified epoxy resins were prepared through the reaction of epoxy resin with polydimethylsiloxanes bearing pendant N-(β-aminoethyl)-γ-aminopropyl groups. The morphology and properties of the cured epoxy resins modified by the polysiloxanes were investigated. It was found that the phase structure and properties of the cured epoxy resins depend mainly on the amino group content in the polydimethylsiloxane and the level of the modifier. The change of phase structure in the cured epoxy resin systems was responsible for the dramatic change in their mechanical and surface properties.

  12. Curing mechanism of furan resin modified with different agents and their thermal strength

    Directory of Open Access Journals (Sweden)

    Huang Renhe

    2011-05-01

    Full Text Available The curing mechanism of furfuryl alcohol and urea-formaldehyde furan resins was investigated using infrared spectroscopy (IR technique. The curing productions of urea-formaldehyde furan resins modified with different agents (i.e. sorbitol, polyester polyol, phenol and acetone and the productions of incomplete curing were characterized by differential thermal analysis (DTA and thermal gravity analysis (TG. The results indicate that except for polyester polyol, the other modifiers have little effect on the thermal strength of urea-formaldehyde furan resin. Furthermore, the thermal strength can be improved at a temperature of higher than 550℃.

  13. Curing mechanism of TDE-85/MeTHPA epoxy resin modified by polyurethane

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-hua; ZHENG Zi-qiao; REN Dong-yan; HUANG Yao-peng

    2007-01-01

    Diglycidyl 4,5-epoxy tetrahydro phthalate/methyl tetrahydrophthalic anhydride (TDE-85/MeTHPA) epoxy resin modified by polyurethane (PU) was prepared with 1,4-butanediol (1,4-BDO), trimethylol propane (TMP) and polyurethane prepolymer synthesized by polypropylene glycol and toluene diisocynate. Chemical reaction and curing mechanism of this system were discussed by incorporating the results of infra spectrum analysis. The results indicate that the epoxy polymeric network Ⅰ is obtained by the curing reaction between TDE-85 and MeTHPA, while the PU polymeric network Ⅱ is obtained by the chain-extended and crosslinking reaction between 1,4-BDO, TMP and polyurethane prepolymer(PUP). The graft chemical bonds are formed between polymer networks Ⅰ and Ⅱ that therefore increase the degree of blend and compatibility between epoxy polymer and PU.

  14. Morphologies and Mechanical Properties of Unsaturated Polyester Resin Modified with TDI

    Institute of Scientific and Technical Information of China (English)

    DUAN Huajun; ZHANG Lianmeng; WANG Jun; YANG Xiaoli

    2008-01-01

    The morphology,mechanical properties of unsaturated polyester(UP)resin modified with TDI were studied via dynamic FT-IR spectra,SEM,DMA and mechanical property testing.Results show that companying with the cured cross-linking reaction of UP resin,TDI can firstly react with UP and produce polyurethane(PU),and then UP and PU form the cross-linking nets together.The impact fracture section morphology of modified UP resin manifested the typical sea-islands structure.Testing of mechanical properties showes that for introducing of PU,the TDI has an obvious effect on the toughness and strength of UP resin.When the ratio of TDI/UP(w/w)was 7.5%,the modified UP resin exhibited the best mechanical properties with

  15. The evaluation of interfaces between MTA and two types of GIC (conventional and resin modified) under an SEM: An in vitro study.

    Science.gov (United States)

    Patil, Anuradha; Aggarwal, Shalini; Kumar, Tanaya; Bhargava, Karan; Rai, Vinay

    2016-01-01

    Mineral trioxide aggregate (MTA) is a biocompatible repair material that is often used along with glass ionomer cement (GIC) in many clinical situations. In this study, the interface of GIC and MTA was examined, and the effect of time on this interface was tested. Forty 9-mm hollow cylindrical glass molds were filled with MTA and then according to the group either conventional GIC or resin-modified GIC (RMGIC) is filled immediately or after 45 min. The specimens were then sectioned, carbon coated, and examined using a scanning electron microscope (SEM) and the elemental analysis was done. Observational study, no statistical analysis done. The SEM showed that both the groups underwent adhesive separation and gap formation at the interface. The specimens in which GIC was condensed over freshly mixed MTA (group IIA and group IIB) also showed cohesive separation in MTA; however, it was more in the GIC condensed after 45 min over MTA groups (group IA and group IB). The results were better for conventional GIC than RMGIC. GIC can be applied over freshly mixed MTA with minimal effects on the MTA, but this effect decreases with time.

  16. The evaluation of interfaces between MTA and two types of GIC (conventional and resin modified) under an SEM: An in vitro study

    Science.gov (United States)

    Patil, Anuradha; Aggarwal, Shalini; Kumar, Tanaya; Bhargava, Karan; Rai, Vinay

    2016-01-01

    Context: Mineral trioxide aggregate (MTA) is a biocompatible repair material that is often used along with glass ionomer cement (GIC) in many clinical situations. Aims: In this study, the interface of GIC and MTA was examined, and the effect of time on this interface was tested. Materials and Methods: Forty 9-mm hollow cylindrical glass molds were filled with MTA and then according to the group either conventional GIC or resin-modified GIC (RMGIC) is filled immediately or after 45 min. The specimens were then sectioned, carbon coated, and examined using a scanning electron microscope (SEM) and the elemental analysis was done. Statistical Analysis: Observational study, no statistical analysis done. Results: The SEM showed that both the groups underwent adhesive separation and gap formation at the interface. The specimens in which GIC was condensed over freshly mixed MTA (group IIA and group IIB) also showed cohesive separation in MTA; however, it was more in the GIC condensed after 45 min over MTA groups (group IA and group IB). The results were better for conventional GIC than RMGIC. Conclusions: GIC can be applied over freshly mixed MTA with minimal effects on the MTA, but this effect decreases with time. PMID:27217640

  17. Comparing the reinforcing effects of a resin modified glassionomer cement, Flowable compomer, and Flowable composite in the restoration of calcium hydroxide-treated immature roots in vitro

    Directory of Open Access Journals (Sweden)

    S Prathibha Rani

    2011-01-01

    Full Text Available One hundred and sixty human permanent central incisors were enlarged to a 120 file size after crown removal procedure to simulate immature teeth. The root canals were filled with calcium hydroxide and stored for 15 days (phase I, 30 days (phase II, 90 days (phase III, and 180 days (Phase IV. At the end of these selected time periods, calcium hydroxide was cleaned off the root canals of forty teeth that were randomly selected and obturated with gutta-percha points in the apical 2 mm of the root canals with a sealer. The specimens were further equally divided into four groups. Unrestored Group I served as control and the root canals of teeth in the other three group specimens were reinforced with resin modified glassionomer cement (RMGIC (Group II, Flowable Compomer (Group III, and Flowable Composite (Group IV, respectively, using a translucent curing post. All specimens were subjected to compressive force using an Instron Testing machine, until fracture occurred. All the materials evaluated substantially reinforced the root specimens compared to the control. At the end of 180 days, Flowable composites showed maximum reinforcement compared to the other groups; however, no significant differences were found between the reinforcement capabilities of Flowable Compomer and RMGIC.

  18. Comparing the reinforcing effects of a resin modified glassionomer cement, Flowable compomer, and Flowable composite in the restoration of calcium hydroxide-treated immature roots in vitro.

    Science.gov (United States)

    Prathibha, Rani S

    2011-01-01

    One hundred and sixty human permanent central incisors were enlarged to a 120 file size after crown removal procedure to simulate immature teeth. The root canals were filled with calcium hydroxide and stored for 15 days (phase I), 30 days (phase II), 90 days (phase III), and 180 days (Phase IV). At the end of these selected time periods, calcium hydroxide was cleaned off the root canals of forty teeth that were randomly selected and obturated with gutta-percha points in the apical 2 mm of the root canals with a sealer. The specimens were further equally divided into four groups. Unrestored Group I served as control and the root canals of teeth in the other three group specimens were reinforced with resin modified glassionomer cement (RMGIC) (Group II), Flowable Compomer (Group III), and Flowable Composite (Group IV), respectively, using a translucent curing post. All specimens were subjected to compressive force using an Instron Testing machine, until fracture occurred. All the materials evaluated substantially reinforced the root specimens compared to the control. At the end of 180 days, Flowable composites showed maximum reinforcement compared to the other groups; however, no significant differences were found between the reinforcement capabilities of Flowable Compomer and RMGIC.

  19. Numerical analysis of cutting glass by dual CO II-laser beams

    Science.gov (United States)

    Jiao, Junke; Wang, Xinbing; Zhang, Xueling; Tang, Wenlong; Liu, Fujun; Lu, Yanzhao

    2008-03-01

    Cutting brittle materials such as ceramics and glass by lasers or traditional saw method, costly fractures and associated damage such as chips and cracks can result. In most cases, these problems were caused as a result of the stress was not controlled properly and exceeded the critical value of the fracture. In this study, a dual-laser-beam method was proposed to avoid fractures in glass laser cutting, where an off-focused CO II-laser beam was scanning on the top surface of glass periodically and repeatedly and a preheated-band which has a proper temperature was built. This preheated-band will reduce the temperature gradients when the glass is cut by the focused CO II-laser beam. Under these conditions, glass can be cut with melting method without any fractures. The process of cutting glass by dual CO II-laser beams was simulated numerically with FEA method and the distribution of temperature and thermal stress was investigated. The relationships between the cutting parameters, such as laser beam diameter, laser power, cutting speed, and the profile of the cutting groove were also discussed. The result showed that thermal stress decreased with the increasing width of preheated-banding, and the smaller the diameter of laser beam, the better the quality of the cutting groove was in the same laser power situation.

  20. Water dynamics in glass ionomer cements

    Science.gov (United States)

    Berg, M. C.; Jacobsen, J.; Momsen, N. C. R.; Benetti, A. R.; Telling, M. T. F.; Seydel, T.; Bordallo, H. N.

    2016-07-01

    Glass ionomer cements (GIC) are an alternative for preventive dentistry. However, these dental cements are complex systems where important motions related to the different states of the hydrogen atoms evolve in a confined porous structure. In this paper, we studied the water dynamics of two different liquids used to prepare either conventional or resin-modified glass ionomer cement. By combining thermal analysis with neutron scattering data we were able to relate the water structure in the liquids to the materials properties.

  1. Glasses

    DEFF Research Database (Denmark)

    Dyre, Jeppe

    2004-01-01

    The temperature dependence of the viscosity of most glassforming liquids is known to depart significantly from the classical Arrhenius behaviour of simple fluids. The discovery of an unexpected correlation between the extent of this departure and the Poisson ratio of the resulting glass could lead...... to new understanding of glass ageing and viscous liquid dynamics....

  2. Glasses

    DEFF Research Database (Denmark)

    Dyre, Jeppe

    2004-01-01

    The temperature dependence of the viscosity of most glassforming liquids is known to depart significantly from the classical Arrhenius behaviour of simple fluids. The discovery of an unexpected correlation between the extent of this departure and the Poisson ratio of the resulting glass could lead...... to new understanding of glass ageing and viscous liquid dynamics....

  3. Class II direct composite resin restorations with beta-quartz glass-ceramic inserts.

    Science.gov (United States)

    Rada, R E

    1993-11-01

    With the increasing demand for esthetic posterior restorations, numerous techniques have been developed. The direct resin restoration has probably been used most extensively in Class II situations. Problems with Class II direct resin restorations include difficulty in developing proximal contact, occlusal wear, and polymerization shrinkage. Beta-quartz glass-ceramic inserts have been developed in an attempt to reduce the incidence of these potential problems. They can be placed in a one-appointment technique, are relatively inexpensive, and can readily be utilized by the clinician adept in placing Class II composite resin restorations.

  4. Bond strength between composite resin and resin modified glass ionomer using different adhesive systems and curing techniques

    OpenAIRE

    Alireza Boruziniat; Samineh Gharaei

    2014-01-01

    Aim: To evaluate bond strength between RMGI and composite using different adhesive systems and curing techniques. Materials and Methods: Sixty prepared samples of RMGI were randomly divided into six groups according to adhesive systems (total-etch, two-step self-etch and all-in-one) and curing techniques (co-curing and pre-curing). In co-curing technique, the adhesive systems were applied on uncured RMGI samples and co-cured together. In the pre-curing technique, before application of adh...

  5. Bond strength between composite resin and resin modified glass ionomer using different adhesive systems and curing techniques.

    Science.gov (United States)

    Boruziniat, Alireza; Gharaei, Samineh

    2014-03-01

    To evaluate bond strength between RMGI and composite using different adhesive systems and curing techniques. Sixty prepared samples of RMGI were randomly divided into six groups according to adhesive systems (total-etch, two-step self-etch and all-in-one) and curing techniques (co-curing and pre-curing). In co-curing technique, the adhesive systems were applied on uncured RMGI samples and co-cured together. In the pre-curing technique, before application of adhesive systems, the RMGI samples were cured. Composite layers were applied and shear bond strength was measured. Two samples of each group were evaluated by SEM. Failure mode was determined by streomicroscope. Both curing methods and adhesive systems had significant effect on bond strength (P-value adhesives had significantly higher shear bond strength than the total-etch adhesive (P-value adhesives, but decreased the bond strength in total-etch adhesive (P-valueadhesive systems and co-curing technique can improve the bond strength between the RMGI and composite.

  6. The effects of surface pretreatment on the microleakage of resin-modified glass-ionomer cement restorations.

    Science.gov (United States)

    Bayrak, S; Sen, Tunc E; Tuloglu, N

    2012-01-01

    To evaluate the effect of different surface pretreatments on the marginal microleakage of Vitremer restorations. Class V cavities were prepared on the labial and lingual surfaces of extracted human third molar teeth. Cavities were randomly distributed into six groups according to surface treatment, as follows: Group NC (negative control): no surface treatment; Group VP (positive control): Vitremer Primer; Group PA: 32% phosphoric acid; Group PAA: 20% polyacrylic acid; Group PLP: self-etch adhesive (Prompt L Pop); Group PB: etch & rinse adhesive (Prime & Bond NT). All cavities were restored with Vitremer. Teeth were thermocycled, stained with 0.5% basic fuchsin dye and sectioned. Microleakage values were quantitatively assessed by linear measurement of dye penetration using image-analyzing software. Differences between occlusal and gingival microleakage values within groups were evaluated using paired t-tests, and differences among groups were analysed using one-way analysis of variance (ANOVA) and Tukey tests. There were statistically significant differences between the occlusal and gingival microleakage values for all groups (p < 0.05). Microleakage differed significantly among surface pretreatment groups (p < 0.001). The negative control and PLP groups showed similar microleakage values, but were significantly higher than other groups for both margins. Although there were no statistically significant differences between positive control and PA, PAA, PB groups, microleakage values of positive control group were smaller than all other experimental groups except for PB group. Vitremer restorations require surface pretreatment to prevent excessive microleakage. Pretreatment with etch & rinse adhesives and Vitremer Primer may reduce microleakage of Vitremer restorations.

  7. Hollow glass microsphere production for laser direct-driven fusion targets on Shen Guang II

    Institute of Scientific and Technical Information of China (English)

    QIU; Longhui(邱龙会); FU; Yibei(傅依备); TANG; Yongjian(唐永建); WEI; Yun(魏芸); ZHENG; Yongming(郑永铭); SHI; Tao(师韬); YAO; Shujiu(姚书久)

    2002-01-01

    A liquid-droplet technique was investigated to fabricate thin wall hollow glass microspheres (HGM) used in laser fusion experiments on Shen Guang II. Glass-forming compositions, operating conditions of the droplet generator and the vertical multiple-zone furnace were optimized. Thin wall HGM with diameters of about 100, 200, and 520 μm were fabricated, whose failure pressures, gas retention properties for D2, and chemical durability were all characterized. The results of the fusion experiments show that the HGM targets are quite satisfactory and the highest neutron yields obtained are 4x 109.

  8. Catalytic curing of novolac cyanate ester resins modified by diallyl bisphenol A%二烯丙基双酚A催化改性酚醛型氰酸酯树脂的催化固化

    Institute of Scientific and Technical Information of China (English)

    马立群; 黄伟; 曲春艳; 王雅珍; 刘洪成; 汪建新

    2013-01-01

      研究了二烯丙基双酚 A(DBA)催化改性酚醛型氰酸酯树脂(cy-5),通过差示扫描量热法(DSC)、热重分析(TG)、冲击性能和动态热机械分析(DMA)测试,分析了改性树脂的热性能和力学性能。研究表明:DBA 对 cy-5有催化和增韧的双重作用,当 DBA 的添加量为5%(质量分数)时,催化效果最为明显,含10% DBA的改性树脂固化物的冲击强度达到7.41 kJ/m2,改性树脂固化物的玻璃化转变温度(Tg)和储能模量(E')均有所降低,但幅度不大。%  Effects of diallyl bisphenol A(DBA) on catalyzing the thermal curing of novolac cyanate ester resin(cy-5) were studied. Thermal and mechanical properties of DBA catalyzed novolac cyanate ester resins were characterized by DSC,TG,impact performance and DMA test. The results showed that DBA can catalyze the curing reaction and toughen the cured resin with dual function,the 5%DBA-catalyzed novolac cyanate ester resin exhibits the best catalytic effect,the impact strength of the cured resin modified by 10% DBA is 7.41 kJ/m2,and the glass transition temperature and storage modulus of the cured resin modified by DBA both decrease slightly.

  9. 二烯丙基双酚A改性氰酸酯树脂的固化动力学及力学性能%Curing Kinetics and Mechanical Properties of Cyanate Ester Resin Modified by Diallyl Bisphenol A

    Institute of Scientific and Technical Information of China (English)

    赵春宝; 汪信; 杨绪杰; 张楠楠

    2012-01-01

    Cyanate ester(CE) resin was modified by diallyl bisphenol A(DBA). The curing kinetic parameters of the modified CE resin were calculated by Flynn-Wall-Ozawa iso-conversional method and Kissinger equation respectively. The mechanical and dynamic mechanical properties of the cured resin were studied. The results show that DBA can catalyze the curing reaction and toughen the cured resin effectively. The activation energy of the CE resin modified by 5% DBA is the minimum (62.16 kJ/mol). The impact strength of the cured CE resin modified by 10% DBA is 2.07 times of that of pure CE resin. The storage modulus and glass transition temperature of the cured CE resin containing DBA both decrease.%采用二烯丙基双酚A(DBA)对氰酸酯树脂(CE)进行改性,分别运用Flynn-Wall-Ozawa等转化率法和Kissinger极值法计算了改性树脂体系的固化动力学参数,并对固化树脂的力学性能和动态力学性能进行了研究.结果表明:DBA对氰酸酯树脂具有明显的催化作用和增韧效果,含5%DBA的改性树脂固化反应活化能最小(62.16kJ/mol),当DBA的加入量为10%时,树脂固化物的冲击强度达到纯氰酸酯树脂的2.07倍,含有DBA的CE树脂固化物的储能模量和玻璃化转变温度均有所降低.

  10. Fluoride rechargability of a non-resin auto-cured glass ionomer cement from a fluoridated dentifrice: An in vitro study

    Directory of Open Access Journals (Sweden)

    A Rao

    2011-01-01

    Full Text Available Background: In addition to their fluoride-releasing properties, glass ionomer cement (GICs have the ability to reuptake and release fluorides from commonly used sources like fluoridated dentifrices. This property has the potential to provide a continuous low concentration of fluoride in the saliva aiding in caries prevention. The superior fluoride-recharging abilities of resin-modified GICs over conventional GICs have been documented. The manufacturer of a non-resin, auto-cured GIC (GC Fuji VII claims fluoride release from the product to be about six times that of conventional GIC. It was hypothesized that perhaps this high fluoride release could translate into a high reuptake and release, when exposed to a 1 000 ppm fluoridated dentifrice every day, thus providing increased fluoride levels in saliva. Aims: This study therefore examined fluoride-recharging abilities of the non-resin, auto-cured glass ionomer cement from a 1 000 ppm fluoridated dentifrice and compared it with resin-modified glass ionomer cement. Materials and Methods: Twelve glass ionomer discs each of resin-modified glass ionomer cement (GC Fuji II L C, Group 1 and the non-resin, auto-cured glass ionomer cement (GC Fuji VII, Group 2 were prepared with precise dimensions of 9 x 2 mm. The 12 specimens in each group were further subdivided into two subgroups of six each. Subgroup A involved no fluoride treatment (Control. Subgroup B involved application of a 1 000 ppm dentifrice for 2 minutes twice daily with a soft toothbrush. The disc-specimens were then suspended in airtight plastic bottles containing exactly 20 ml double distilled water. The fluoride concentration of the water in which the specimen discs were immersed was measured by means of a fluoride ion selective electrode connected to an ion selective electrode meter/digital ion analyzer at 1, 2, 7, 15, and 30 days. Statistical Analysis: It was performed using the Kruskal-Wallis Test. Results and Conclusion: Fuji VII

  11. Glass polymorphism in glycerol-water mixtures: II. Experimental studies.

    Science.gov (United States)

    Bachler, Johannes; Fuentes-Landete, Violeta; Jahn, David A; Wong, Jessina; Giovambattista, Nicolas; Loerting, Thomas

    2016-04-28

    We report a detailed experimental study of (i) pressure-induced transformations in glycerol-water mixtures at T = 77 K and P = 0-1.8 GPa, and (ii) heating-induced transformations of glycerol-water mixtures recovered at 1 atm and T = 77 K. Our samples are prepared by cooling the solutions at ambient pressure at various cooling rates (100 K s(-1)-10 K h(-1)) and for the whole range of glycerol mole fractions, χ(g). Depending on concentration and cooling rates, cooling leads to samples containing amorphous ice (χg ≥ 0.20), ice (χ(g) ≤ 0.32), and/or "distorted ice" (0 density amorphous ice (HDA). PIA of ice domains within the glycerol-water mixtures is shown to be possible only up to χ(g) ≈ 0.32 (T = 77 K). This is rather surprising since it has been known that at χ(g) solution of χ(g) ≈ 0.38. Accordingly, in the range 0.32 density amorphous ice) transformation. At 0.15 glycerol-water domains and, finally, the melting of ice at high temperatures. Our work exemplifies the complex "phase" behavior of glassy binary mixtures due to phase-separation (ice formation) and polyamorphism, and the relevance of sample preparation, concentration as well as cooling rates. The presence of the distorted ice (called "interphase" by us) also explains the debated "drift anomaly" upon melting. These results are compatible with the high-pressure study by Suzuki and Mishima indicating disappearance of polyamorphism at P ≈ 0.03-0.05 GPa at χ(g) ≈ 0.12-0.15 [J. Chem. Phys., 2014, 141, 094505].

  12. Inhibition of early biofilm formation by glass-ionomer incorporated with chlorhexidine in vivo: a pilot study.

    NARCIS (Netherlands)

    Du, X.; Huang, X.; Huang, C.; Frencken, J.E.F.M.; Yang, T.

    2012-01-01

    BACKGROUND: This pilot study investigated the antibiofilm effects of glass-ionomer cements (GICs) and resin-modified glass-ionomer cements (RMGICs) incorporated with chlorhexidine (CHX) in vivo. METHODS: Experimental GICs and RMGICs containing 2% CHX were obtained by mixing CHX with the powder of GI

  13. Amino acid containing glass-ionomer cement for orthopedic applications

    Science.gov (United States)

    Wu, Wei

    Amino acid containing glass-ionomer cements were synthesized, formulated, and evaluated for orthopedic application. The formulation of different amino acid containing glass-ionomer bone cements was optimized, and conventional and resin-modified glass-ionomer bone cements were compared. Properties of interest included handling characteristics, physical and chemical properties, and mechanical strength of the bone cement. The study was based on the synthesis of different vinyl containing amino acids, different polyelectrolytes containing these amino acid residues, and different resin-modified polyelectrolytes, as well as formulation and evaluation of conventional and resin-modified glass-ionomer bone cements using these polyelectrolytes. Systematic preparation of polyelectrolytes and formulation of glass-ionomer bone cements were essential features of this work, since we anticipated that the mechanical properties of the glass-ionomer bone cements could be strongly affected by the nature of the polyelectrolytes and formulation. Mechanical properties were evaluated in a screw driven mechanical testing machine, and structure-property relationships were determined by scanning electron microscopic (SEM) observation of the fracture surface of the specimens. How the structure of polyelectrolytes, such as different amino acid residues, molecular weight, different modifying resin, and formulation of glass-ionomer bone cement, affected the mechanical properties was also studied.

  14. Compressive strength of two newly developed glass-ionomer materials for use with the Atraumatic Restorative Treatment (ART) approach in class II cavities.

    NARCIS (Netherlands)

    Koenraads, H.; Kroon, G. Van der; Frencken, J.E.F.M.

    2009-01-01

    OBJECTIVES: The null-hypotheses tested were that no difference in compressive strength of ART class II cavities exists between those restored with (1) glass-carbomer and a commonly used glass-ionomer; (2) KMEM and the commonly used glass-ionomer and; (3) glass-carbomer and KMEM. METHODS: 100 molar t

  15. Sealing ability of a new calcium silicate based material as a dentin substitute in class II sandwich restorations: An in vitro study

    Directory of Open Access Journals (Sweden)

    Raji Viola Solomon

    2014-01-01

    Full Text Available Background: Class ll sandwich restorations are routinely performed where conventional Glass ionomer cement (GIC or Resin-modified GIC (RMGIC is used as a base or dentin substitute and a light curing composite resin restorative material is used as an enamel substitute. Various authors have evaluated the microleakage of composite resin restorations where glass ionomer cement has been used as a base in class II sandwich restorations, but a literature survey reveals limited studies on the microleakage analysis of similar restorations with biodentine as a dentin substitute, as an alternative to glass ionomer cement. The aim of this study is: To evaluate the marginal sealing efficacy of a new calcium-silicate-based material (Biodentine as a dentin substitute, at the cervical margins, in posterior class II sandwich restorations.To compare and evaluate the microleakage at the biodentine/composite interface with the microleakage at the resin-modified GIC/composite interface, in posterior class II open sandwich restorations. To compare the efficacy between a water-based etch and rinse adhesive (Scotch bond multipurpose and an acetone-based etch and rinse adhesive (Prime and bond NT, when bonding biodentine to the composite. To evaluate the enamel, dentin, and interfacial microleakage at the composite and biodentine/RMGIC interfaces. Materials and Methods: Fifty class II cavities were prepared on the mesial and distal surfaces of 25 extracted human maxillary third molars, which were randomly divided into five groups of ten cavities each: (G1 Biodentine group, (G2 Fuji II LC GIC group, (G3 Biodentine as a base + prime and bond NT + Tetric N-Ceram composite, (G4 Biodentine + scotchbond multi-purpose + Tetric N-Ceram composite, (G5 Fuji II LC as a base + prime and bond NT+ Tetric-N Ceram composite. The samples were then subjected to thermocycling, 2500× (5°C to 55°C, followed by the dye penetration test. Scores are given from 0 to 3 based on the depth of

  16. COMPARISON OF TREATMENT RESULTS OF CLASS N FURCATION INVOLVEMENT IN MANDIBULAR MOLARS WITH FLAP SURGERYWITH AND WITHOUTMODIFIED GLASS IONOMER RESIN

    Directory of Open Access Journals (Sweden)

    HA GOLESTANE

    2002-09-01

    Full Text Available Introduction. The treatment of furcation involvement is difficult due to the anatomic problems that interfere with the clinician"s accessibility in treating the area and the patient"s ability in maintanining adequate plaque control afterwards. The goal of traditional methods of treatment is to arrest the progression of the bone loss. the ratio of success with these methods has been poor, except for grade I involvements. Guided tissue regeneration has improved the long-term prognosis of many deep grade II lesions but has not always shown consistent predictability. The purpose of this study was to evaluate the clinical effectiveness of a resin modified glass ionomer as a barrier in the treatment of class 11furcation defect in mandibular molars. Methods. Twenty six (13 eperimental and 13 control defects were treated in 13 patients that presenting matched pair defects. The following clinical measurments were taken at baseline (after phase I and 6 month after surgery: plaque index bleeding index, gingival recession, probing pocket depth, probing attachment level. Healing was uneventhful in all cases and barrier remained in place. Results. No statistically singificant difference was found between the experiment group (use the resin modified glass ionomer and control group (use the flap surgery alone respectively. Plaque index reduction (1.38±0.65 VS 1.24±0.45 bleeding index reduction (0.6±0.48 VS 0.69 ± 0.48 (Mean ± SD and gingival recession (0.3 ± 0.48 VS 0.27±0.57 and reduction probing pocket depth (2.38±0.74 VS 2.92±0.38 were noted. but statistically significant difference in gain of probing attachment level (3.07 ± 0.67 VS 1.96±1.07 were found. Discussion. The study offers another treatment plan in the treatment of futcation defect molars. More study may be necessary to evaluate efficacy and adverse effects of resin modified glass ionomer.

  17. Anti-biofilm Effect of Glass Ionomer Cements Incorporated with Chlorhexidine and Bioaetive Glass

    Institute of Scientific and Technical Information of China (English)

    HUANG Xueqing; YANG Tiantian; ZHAO Suling; HUANG Cui; DU Xijin

    2012-01-01

    The effect of glass ionomer cement and resin-modified glass ionomer cement incorporated with chlorhexidine and bioactive glass on antimicrobial activity and physicochemical properties were investigated.The experimental results showed that groups incorporated with 1% chlorhexidine exhibited a significant reduction of optical density values of the bacterial suspension and increased the degradation of Streptococcus mutans biofilm.However,groups incorporated with 10% bioactive glass did not affect the optical density values and the biofilm formation.The mechanical properties of the materials and the polymerization were not influenced by the addition of chlorhexidine.Nevertheless,the compressive strength was lower when the materials were incorporated with bioactive glass.It can be concluded that glass ionomer cements incorporated with chlorhexidine can maintain its mechanical properties as well as reduce early S mutans biofilm formation.Controlled release/sustained release technology may be required to optimize the antibacterial activity of glass ionomer cements incorporated with bioactive glass.

  18. Surface silver-doping of biocompatible glasses to induce antibacterial properties. Part II: Plasma sprayed glass-coatings.

    Science.gov (United States)

    Miola, M; Ferraris, S; Di Nunzio, S; Robotti, P F; Bianchi, G; Fucale, G; Maina, G; Cannas, M; Gatti, S; Massé, A; Vitale Brovarone, C; Verné, E

    2009-03-01

    A 57% SiO(2), 3% Al(2)O(3), 34% CaO and 6% Na(2)O glass (SCNA) has been produced in form of powders and deposited by plasma spray on titanium alloy and stainless steel substrates. The obtained coatings have been subjected to a patented ion-exchange treatment to introduce silver ions in the surface inducing an antibacterial behavior. Silver surface-enriched samples have been characterized by means of X-ray diffraction, SEM observation, EDS analysis, in vitro bioactivity tests, leaching tests by GFAAS (graphite furnace atomic adsorption spectroscopy) analyses, cells adhesion and proliferation, and antibacterial tests using Staphylococcus Aureus strain. In vitro tests results showed that the modified samples acquired an antimicrobial action against tested bacteria maintaining unaffected the biocompatibility of the glass. Furthermore the ion-exchange treatment can be successfully applied to glass-coated samples without affecting the properties of the coatings; the simplicity and reproducibility of the method make it suitable for glass or glass-ceramic coatings of different composition in order to produce coated devices for bone healing and/or prostheses, able to reduce bacterial colonization and infections risks.

  19. The effects of glass ionomer and flowable composite liners on the fracture resistance of open-sandwich class II restorations.

    Science.gov (United States)

    Güray Efes, Begüm; Yaman, Batu Can; Gümüştaş, Burak; Tıryakı, Murat

    2013-01-01

    This in vitro study aimed to investigate the effects of glass-ionomer and flowable composite liners on the fracture resistance of Class II amalgam and composite restorations. Group 1 cavities were restored with amalgam and Group 4 cavities with nanofill composite after the application of a dentin-bonding agent. For the remaining groups, light-cured-glass-ionomer liner was used in a gingival floor proximal box (Groups 2, 5) or flowable composite was used as a liner (Groups 3, 6), the remainder of the cavity was restored with amalgam (Groups 2, 3) or composite (Groups 5, 6). The restorations were loaded in compression to failure. The data was analyzed using Tukey's multiple comparison test. The fracture resistance was significantly higher (p0.05). Flowable composite, glass-ionomer liners increased the fracture resistance of open-sandwich Class II amalgam restorations.

  20. Efficacy of four lining materials in sandwich technique to reduce microleakage in class II composite resin restorations.

    Science.gov (United States)

    Moazzami, S M; Sarabi, N; Hajizadeh, H; Majidinia, S; Li, Y; Meharry, M R; Shahrokh, H

    2014-01-01

    The aim of the present study was to evaluate the effect of four different sandwich techniques on gingival microleakage of Class II direct composite resin restorations. Fifty sound human premolars were selected and randomly divided into five groups (n=10). Class II box only cavities were prepared in one of the proximal surfaces of each tooth with a gingival margin located approximately 0.5 mm below the cemento-enamel junction. Group A (control) was restored incrementally with composite resin (Tetric Ceram). Groups B, C, D, and E were restored with the sandwich technique using a compomer (Compoglass F), flowable composite resin (Tetric Flow), self-cure composite resin (Degufill SC), or resin modified glass ionomer (Fuji II LC), respectively. After thermal-load cycling, the specimens were immersed in 0.5% basic fuschin for 24 hours. Dye penetration (10(-1) mm) was detected using a sectioning technique. Data were analyzed with repeated measurements and Duncan test at α=0.05. The least amount of microleakage was detected in the incremental group (1.28 ± 0.98). The sandwich technique using resin modified glass ionomer (7.99 ± 9.57) or compomer (4.36 ± 1.78) resulted in significantly more leakage than did the sandwich technique using flowable (1.50 ± 1.97) or self-cure composite (2.26 ± 1.52). According to the results of this study, none of the four sandwich technique composite resin restorations used in this study could reduce gingival microleakage to a greater degree than the incremental technique.

  1. A Review of Glass-Ionomer Cements for Clinical Dentistry.

    Science.gov (United States)

    Sidhu, Sharanbir K; Nicholson, John W

    2016-06-28

    This article is an updated review of the published literature on glass-ionomer cements and covers their structure, properties and clinical uses within dentistry, with an emphasis on findings from the last five years or so. Glass-ionomers are shown to set by an acid-base reaction within 2-3 min and to form hard, reasonably strong materials with acceptable appearance. They release fluoride and are bioactive, so that they gradually develop a strong, durable interfacial ion-exchange layer at the interface with the tooth, which is responsible for their adhesion. Modified forms of glass-ionomers, namely resin-modified glass-ionomers and glass carbomer, are also described and their properties and applications covered. Physical properties of the resin-modified glass-ionomers are shown to be good, and comparable with those of conventional glass-ionomers, but biocompatibility is somewhat compromised by the presence of the resin component, 2 hydroxyethyl methacrylate. Properties of glass carbomer appear to be slightly inferior to those of the best modern conventional glass-ionomers, and there is not yet sufficient information to determine how their bioactivity compares, although they have been formulated to enhance this particular feature.

  2. A Review of Glass-Ionomer Cements for Clinical Dentistry

    Directory of Open Access Journals (Sweden)

    Sharanbir K. Sidhu

    2016-06-01

    Full Text Available This article is an updated review of the published literature on glass-ionomer cements and covers their structure, properties and clinical uses within dentistry, with an emphasis on findings from the last five years or so. Glass-ionomers are shown to set by an acid-base reaction within 2–3 min and to form hard, reasonably strong materials with acceptable appearance. They release fluoride and are bioactive, so that they gradually develop a strong, durable interfacial ion-exchange layer at the interface with the tooth, which is responsible for their adhesion. Modified forms of glass-ionomers, namely resin-modified glass-ionomers and glass carbomer, are also described and their properties and applications covered. Physical properties of the resin-modified glass-ionomers are shown to be good, and comparable with those of conventional glass-ionomers, but biocompatibility is somewhat compromised by the presence of the resin component, 2 hydroxyethyl methacrylate. Properties of glass carbomer appear to be slightly inferior to those of the best modern conventional glass-ionomers, and there is not yet sufficient information to determine how their bioactivity compares, although they have been formulated to enhance this particular feature.

  3. Glass mirrors by cold slumping to cover 100 m2 of the MAGIC II Cherenkov telescope reflecting surface

    Science.gov (United States)

    Pareschi, G.; Giro, E.; Banham, R.; Basso, S.; Bastieri, D.; Canestrari, R.; Ceppatelli, G.; Citterio, O.; Doro, M.; Ghigo, M.; Marioni, F.; Mariotti, M.; Salvati, M.; Sanvito, F.; Vernani, D.

    2008-07-01

    We report on the production and implementation of 100 square panels 1 m x 1 m, based on the innovative approach of cold slumping of thin glass sheets. The more than 100 segments will cover around one half of the 240 m-square reflecting surface of the MAGIC II, a clone of the atmospheric Cherenkov telescope MAGIC I (with a single-dish 17 m diameter mirror) which is already operating since late 2003 at La Palma. The MAGIC II telescope will be completed by the end of 2008 and will operate in stereoscopic mode with MAGIC I. While the central part of the of the reflector is composed of by diamond milled Aluminum of 1m2 area panels (following a design similar to that already used for MAGIC I), the outer coronas will be made of sandwiched glass segments. The glass panel production foresees the following steps: a) a thin glass sheet (1-2mm) is elastically deformed so as to retain the shape imparted by a master with convex profile - the radius of curvature is large, the sheet can be pressed against the master using vacuum suction -; b) on the deformed glass sheet a honeycomb structure that provides the needed rigidity is glued ; c) then a second glass sheet is glued on the top in order to obtain a sandwich; d) after on the concave side a reflecting coating (Aluminum) and a thin protective coating (Quartz) are deposited. The typical weight of each panel is about 12 kg and its resolution is better than 1 mrad at a level of diameter that contains the 90% of the energy reflected by the mirror; the areal cost of glass panels is ~2 k per 1m2. The technology based on cold slumping is a good candidate for the production of the primary mirrors of the telescopes forming the Cherenkov Telescope Array (CTA), the future large TeV observatory currently being studied in Europe. Details on the realization of MAGIC II new mirrors based on cold slumping glass will be presented.

  4. Evaluation of cavity wall adaptation of bulk esthetic materials to restore class II cavities in primary molars.

    Science.gov (United States)

    Gaintantzopoulou, Maria D; Gopinath, Vellore K; Zinelis, Spiros

    2017-05-01

    The purpose of the study was to assess the cavity wall adaptation and gap formation of a bulk fill composite resin and reinforced conventional glass ionomer cement and a resin-modified glass ionomer cement in class II restorations on primary molars. Standardized class II slot cavity preparations were prepared in exfoliating primary molars. Teeth were restored with one of the three tested materials (n = 10): SonicFill bulk fill composite resin (SF), EQUIA Fil conventional reinforced glass ionomer cement (EQF), and Vitremer resin-reinforced glass ionomer cement (VT). Cavity wall adaptation of the restorations was investigated by computerized X-ray micro-tomography and the percentage void volume fraction (%VVF) was calculated. Same specimens were sectioned and the interfaces were evaluated by reflection optical microscopy to measure the percentage linear length (%LD) of the interfacial gaps. Samples were further evaluated by environmental scanning electron microscopy (ESEM). EQF and SF showed significantly lower %VVF and %LD values than VT (p materials showed good cavity wall adaptation. Short operating time and good cavity wall adaptation are advantages of the materials in restorative and pediatric dentistry, especially while working on children with limited attention span.

  5. THE EFFECT OF THE APPLICATION OF 20% CARBAMIDE PEROXIDE ON THE GLASS IONOMER CEMENT TYPE II SURFACE HARDNESS

    Directory of Open Access Journals (Sweden)

    Ali Noerdin

    2015-06-01

    Full Text Available In dental bleaching, carbamide peroxide is usually used at concentration of 10%, 15%, to 20%. The result of our previous study showed that the application of 10% and 15% carbamide peroxide bleaching agent has increased the surface hardness of glass ionomer cement. The purpose of this study was to observe the effect of 20% carbamide peroxide bleaching to glass ionomer surface hardness. Twenty specimens of glass ionomer type II after exposed to 20% carbamide peroxide were divided into two application time groups: 4 and 8 hours per day. Glass ionomer cement surface hardness was measured by Vickers Microhardness Tester series HMV-2 with a weight of 0,025 Hv for 20 seconds. The measurement was conducted at before/no application, after a week, and after 2 weeks of application in both groups. It can be concluded that the application of 20% carbamide peroxide bleaching agent could increase the surface hardness of glass ionomer cement after 1 week and 2 weeks application period.

  6. GLASSES CONTAINING IRON (II III) OXIDES FOR IMMOBILIZATION OF RADIOACTIVE TECHNETIUM

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; HEO J; XU K; CHOI JK; HRMA PR; UM W

    2011-11-07

    Technetium-99 (Tc-99) has posed serious environmental threats as US Department of Energy's high-level waste. This work reports the vitrification of Re, as surrogate for Tc-99, by iron-borosilicate and iron-phosphate glasses, respectively. Iron-phosphate glasses can dissolve Re as high as {approx} 1.2 wt. %, which can become candidate waste forms for Tc-99 disposal, while borosilicate glasses can retain less than 0.1 wt. % of Re due to high melting temperature and long melting duration. Vitrification of Re as Tc-99's mimic was investigated using iron-borosilicate and iron-phosphate glasses. The retention of Re in borosilicate glasses was less than 0.1 wt. % and more than 99 wt. % of Re were volatilized due to high melting temperature and long melting duration. Because the retention of Re in iron-phosphate glasses is as high as 1.2 wt. % and the volatilization is reduced down to {approx}50 wt. %, iron-phosphate glasses can be one of the glass waste form candidates for Tc (or Re) disposal. The investigations of chemical durability and leaching test of iron-phosphate glasses containing Re are now underway to test the performance of the waste form.

  7. Bioalteration of synthetic Fe(III)-, Fe(II)-bearing basaltic glasses and Fe-free glass in the presence of the heterotrophic bacteria strain Pseudomonas aeruginosa: Impact of siderophores

    Science.gov (United States)

    Perez, Anne; Rossano, Stéphanie; Trcera, Nicolas; Huguenot, David; Fourdrin, Chloé; Verney-Carron, Aurélie; van Hullebusch, Eric D.; Guyot, François

    2016-09-01

    This study aims to evaluate the role of micro-organisms and their siderophores in the first steps of the alteration processes of basaltic glasses in aqueous media. In this regard, three different types of glasses - with or without iron, in the reduced Fe(II) or oxidized Fe(III) states - were prepared on the basis of a simplified basaltic glass composition. Control and Pseudomonas aeruginosa inoculated experiments were performed in a buffered (pH 6.5) nutrient depleted medium to stimulate the production of the pyoverdine siderophore. Results show that the presence of P. aeruginosa has an effect on the dissolution kinetics of all glasses as most of the calculated elemental release rates are increased compared to sterile conditions. Reciprocally, the composition of the glass in contact with P. aeruginosa has an impact on the bacterial growth and siderophore production. As an essential nutrient for this microbial strain, Fe notably appears to play a central role during biotic experiments. Its presence in the glass stimulates the bacterial growth and minimizes the synthesis of pyoverdine. Moreover the initial Fe2+/Fe3+ ratio in the glasses modulates this synthesis, as pyoverdine is not detected at all in the system in contact with Fe(III)-bearing glass. Finally, the dissolution rates appear to be correlated to siderophore concentrations as they increase with respect to sterile experiments in the order Fe(III)-bearing glass < Fe(II)-bearing glass < Fe-free glass. This increase is attributed to complexation reactions between siderophores and Fe or Al for Fe(II)-bearing glass or Fe-free glass, respectively. The dissolution of an Fe-free glass is significantly improved in the presence of bacteria, as initial dissolution rates are increased by a factor of 3. This study attests to the essential role of siderophores in the P. aeruginosa-promoted dissolution processes of basaltic glasses as well as to the complex relationships between the nutritional potential of the glass and

  8. Nanodiamond in tellurite glass Part II: practical nanodiamond-doped fibers

    CERN Document Server

    Ruan, Yinlan; Johnson, Brett C; Ohshima, Takeshi; Greentree, Andrew D; Gibson, Brant C; Monro, Tanya M; Ebendorff-Heidepriem, Heike

    2014-01-01

    Tellurite glass fibers with embedded nanodiamond are attractive materials for quantum photonics applications. Reducing the loss of these fibers in the 600-800 nm wavelength range of nanodiamond fluorescence is essential to exploit the unique properties of nanodiamond in the new hybrid material. The first part of this study reported the origin of loss in nanodiamond-doped glass and impact of glass fabrication conditions. Here, we report the fabrication of nanodiamond-doped tellurite fibers with significantly reduced loss in the visible through further understanding of the impact of glass fabrication conditions on the interaction of the glass melt with the embedded nanodiamond. We fabricated tellurite fibers containing nanodiamond in concentrations up to 0.7 ppm-weight, while reducing the loss by more than an order of magnitude down to 10 dB/m at 600-800 nm.

  9. Study of expoxy resins modified by soluble poly (ether ether ketone) and poly (ether ether ketone)%可溶性聚醚醚酮改性环氧树脂的研究

    Institute of Scientific and Technical Information of China (English)

    孙攀; 史翎; 张军营

    2011-01-01

    A series of epoxy resins modified soluble poly ( ether ether ketone) (s-PEEK) have been prepared by a hot-melt method. The resulting modified epoxy resins were compared with epoxy resins modified with poly ( ether ether ketone) (PEEK). The effect of the type of PEEK and its content on the gelation time, impact strength, flexural properties and fracture morphology of the resulting materials were studied and the glass transition temperatures (Tg) and thermal stabilities of the modified materials were compared. The experimental results showed that the impact properties, flexural properties, Tg and thermal stability were all improved by addition of both types of PEEK. The impact strength of the cured materials (with a mass ratio of epoxy resin to s-PEEK or PEEK of 100: 5) were 42.6 and 46.6 kJ/m2 , respectively, representing increases in the values for the pure epoxy resin of 69.1% and 85.6%, respectively. When the mass ratio of epoxy resin to s-PEEK was 100: 25, the value of Tg was about 179.1 ℃. Scanning electron microscopy showed that the s-PEEK-toughened epoxy resins were homogeneous systems, while the PEEK toughened epoxy resins were granule-enforced systems.%采用热熔法制备了一系列可溶性聚醚醚酮(s-PEEK)改性环氧树脂(EP),并与普通聚醚醚酮(PEEK)改性环氧体系进行比较,探讨了聚醚醚酮类型、用量对改性树脂固化体系的凝胶时间、冲击强度、弯曲性能和断裂形貌的影响,并对含s-PEEK树脂体系的玻璃化转变温度(Tg)和热稳定性进行了分析.结果表明,s-PEEK和PEEK可在提高环氧体系冲击性能的同时,提高材料的弯曲性能、玻璃化温度和热稳定性;当m(s-PEEK):m(E-51)和m(PEEK):m(E-51)均为5:100时,冲击强度达到42.6和46.6 kJ/m2,分别比未改性的环氧体系提高69.1%和85.6%;m(s-PEEK):m(E-51)=25:100时,Tg=179.1℃,比未改性环氧树脂提高20℃左右;且含s-PEEK的体系是均相体系,含s-PEEK的固化物是颗粒增强体系.

  10. Morphologic assessment of dental surface/ glass ionomer cement interface: influence of Er:YAG laser pretreatment

    Directory of Open Access Journals (Sweden)

    Silmara Aparecida Milori Corona

    2012-12-01

    Full Text Available Introduction and objective: The aim of this study was to assess the surface and the substrate/glass ionomer cement (GIC interface after Er:YAG laser irradiation by means of scanning electron microcopy. Material and methods: Thirty human third molars were selected and had their roots removed. Crowns were sectioned to obtain discs that were randomly assigned to three groups according to the surface pretreatment: 40% polyacrylic acid (control; Er:YAG laser irradiation (80mJ/2Hz or Er:YAG laser followed by 40% polyacrylic acid. Two discs of each group were put aside to the surface analysis and the others were bisected. One half received Ketac-Fil and the other received Fuji II LC. Specimens were prepared for SEM and were analyzed under different magnifications. Results: Er:YAG laser group showed no adhesive interface for both enamel and dentin, but strongly damaged the interface build-up for dentin/Fuji II LC. The application of laser irradiation followed by the polyacrylic acid exhibited gaps and irregularities for both substrates. Conclusion: Er:YAG laser irradiation combined or not with 40% polyacrylic acid produced a surface unfavorable for GIC interaction, especially for the resin-modified ones.

  11. Effect of acid pre-conditioning and/or delayed light irradiation on enamel bond strength of three resin-modified glass ionomers

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2013-01-01

    Conclusion: Within the limitations of the present study, the effect of acid pre-conditioning, delaying irradiation and both on enamel bond strength of RMGIs was material-dependent. Further investigations are recommended.

  12. Response to a field of the D = 3 Ising spin glass with Janus and JanusII dedicated computers

    Science.gov (United States)

    Seoane, Beatriz; Janus Collaboration Collaboration

    Using the Janus dedicated computer, and its new generation JanusII, we study the linear response to a field of the Edwards-Anderson model for times that cover twelve orders of magnitude. The fluctuation-dissipation relations are investigated for several values of tw. We observe that the violations of the fluctuation-dissipation theorem can be directly related to the P (q) measured in equilibrium at finite sizes, although a simple statics-dynamics dictionary L ξ (tw) is not enough to account for the behavior at large times. We show that the equivalence can be easily restored by taking into account the growth of ξ (t +tw) . Interestingly, experimental measurements of the spin glass correlation length rely precisely on the response of a spin glass to a field, although a direct relation between the measured object and the real ξ has never been established. In this work, we mimic the experimental protocol with Janus data, which lets us relate the experimental ξ with the length extracted from the spatial correlation function. These results allow us for the first time to make a quantitative comparison between experiments and simulations, finding a surprising good agreement with measurements in superspin glasses. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 654971, the ERC grant CRIPHERASY (no. 247328) and from the MINECO(Spain) (No. FIS2012-35719-C02).

  13. Investigations in silicate glasses. I. Radiation damage. II. Optical nonlinearity. [Gamma rays and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Moran, M.J.

    1976-11-15

    The investigation of two poorly understood but technologically important physical properties of silicate glasses and related materials is described. The use of Electron Paramagnetic Resonance to investigate the nature of radiation-induced damage in glasses exposed to a variety of high-energy radiation sources is discussed first. Second, the measurement of the nonlinear index of refraction coefficient in a variety of optical materials related to the design of high-power laser systems is described. The radiation damage investigations rely heavily on the comparison of experimental results for different experimental situations. The comparison of EPR lineshapes, absolute spin densities and power saturation behavior is used to probe a variety of microscopic and macroscopic aspects of radiation damage in glasses. Comparison of radiation damage associated with exposure to gamma rays and fast neutrons (and combinations thereof) are interpreted in terms of the microscopic damage mechanisms which are expected to be associated with the specific radiations. Comparison of radiation damage behavior in different types of glasses is also interpreted in terms of the behavior expected for the specific materials. The body of data which is generated is found to be internally self-consistent and is also generally consistent with the radiation damage behavior expected for specific situations. A new and versatile technique for measuring the nonlinear index of refraction coefficient, n/sub 2/, in optical materials is described. The technique utilizes a 1 ns pulsed neodymium-glass laser system and time-resolved interferometry to determine the ratio of the coefficient n/sub 2/ of sample materials to the n/sub 2/ of CS/sub 2/. This method avoids some of the complications associated with performing absolute measurements of n/sub 2/ and allows the use of a relatively simple experimental technique. The measurements determine the nonlinear index ratios of the samples with an accuracy of about

  14. Thermodynamic aspects of the glass transition phenomenon. II. Molecular liquids with variable interactions

    Science.gov (United States)

    Alba-Simionesco, C.; Fan, J.; Angell, C. A.

    1999-03-01

    As a contribution to the understanding of the thermodynamics of the glass transition phenomenon a series of molecules having the same steric character, but differing in the strength and nature of intermolecular interactions, has been investigated. The series is based on systematic changes of substituents on disubstituted benzene ring compounds, the simplest example of which is meta-xylene. Meta-isomers are chosen in each instance because of their greater tendency to supercool. In particular, m-fluoroaniline cannot be crystallized at ambient pressure. The principal measurements performed were of heat capacity and enthalpy change, using the technique of differential scanning calorimetry, and these have been examined in the light of literature data on the liquid viscosities and some recent data for dielectric relaxation. As the strength of hydrogen-bonding interactions between the ring substituents on adjacent molecules increases, the glass transition temperature Tg increases by almost 100 degrees from the lowest value in the series, 122.5 K, for m-fluorotoluene. Empirical rules involving Tb/Tm and Tg/Tm are found wanting. The important thermodynamic characteristic of the glass transition, viz., the change in heat capacity at the glass transition, ΔCp, remains approximately constant until the -OH substituent is introduced, whereupon a new element appears. This is a specific component of ΔCp which appears at temperatures above an initially small jump at Tg. It is well accounted for by the addition of a two-state H-bond breaking component (with the usual H⋯-OH bond energy) to the total excess heat capacity. The liquid ground state (or Kauzmann) temperature TK assessed from thermodynamic data acquired in this study, falls 20%-30% below the glass transition temperature. From the limited transport data available, these liquids appear to be quite fragile in character implying that the phenyl group influence dominates the hydrogen bond factor which has often seemed

  15. Foaming of E-Glass II (Report for G Plus Project for PPG)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Sang; Portch, Matthew P.; Matyas, Josef; Hrma, Pavel R.; Pilon, Laurent

    2005-09-23

    In a previous study, the effect of the furnace atmosphere on E glass foaming was investigated with the specific goal to understand the impact of increased water content on foaming in oxy-fired furnaces. The present study extended the previous study and focused on the effect of glass batch chemical composition on E-glass foaming. The present study also included reruns of foam tests performed in a previous study, which resulted in the same trend: the foaming extent increased nearly linearly with the heating rate and no foam was produced when CO2 + 55% H2O atmosphere was introduced at 300°C. It was shown that the lack of foaming in the test with CO2 + 55% H2O atmosphere introduced at 300°C was caused by a loss of sulfate at T <1250°C because of higher water content at the early stages of melting. The tests with new batches in the present study showed that replacing quicklime with limestone tend to decrease foaming, possibly caused by increased sulfate loss during early stages of melting in the batch with limestone. The batches where Na2SO4 was replaced with NaNO3, NaNO3 + CeO2, or CeO2, produced only very limited foaming regardless of the replacing components. As expected, the foaming extent increased as the sulfate content in the batch increased. The results of the present study suggest that foaming can be reduced by using limestone over quicklime and by decreasing the sulfate addition to a minimum required for refining.

  16. High energy pA collisions in the color glass condensate approach II. Quark production

    CERN Document Server

    Blaizot, J P; Venugopalan, R

    2004-01-01

    We compute the production of quark-antiquark pairs in high energy collisions between a small and a large projectile, as in proton-nucleus collisions, in the framework of the Color Glass Condensate. We derive a general expression for quark pair-production, which is not k_t-factorizable. However, k_t-factorization is recovered in the limit of large mass pairs or large quark--anti-quark momenta. Our results are amenable to a simple interpretation and suggest how multi-parton correlations at small x can be quantified in high-energy proton/deuteron-nucleus collisions.

  17. perbedaan dua bahan glass ionomer terhadap kebocoran tepi pada restorasi kelas II yang menggunakan teknik open sandwich

    OpenAIRE

    juliana, andi riska

    2012-01-01

    2011 Kebocoran tepi merupakan salah satu faktor terjadinya kegagalan restorasi. Salah satu cara untuk mengatasi kebocoran tersebut dengan restorasi sandwich yang menggunakan dua macam bahan yaitu semen glass ionomer dan resin komposit. Semen glass ionomer mempunyai kekurangan sifat fisik antara lain kelarutan yang tinggi dan pengerasan yang lambat. Penelitian ini bertujuan untuk mengetahui perbedaan pada dua bahan glass ionomer yaitu glass ionomer konvensional dan glass ionomer modifikas...

  18. Epoxy Resin Modified Carboxyl-terminated Nitrile Rubber%端羧基丁腈橡胶改性环氧树脂的研究

    Institute of Scientific and Technical Information of China (English)

    陈青; 宫大军; 魏伯荣; 柳丛辉

    2011-01-01

    Using 2-ethyl-4-methyl imidazole as curing agent, pre-polymerization and curing reaction of epoxy resin modified by carboxyl-terminated nitrile rubber(CTBN) were analyzed by infrared spectroscopy.By testing the impact strength, flexural strength, tensile shear strength of modified cured epoxy resin, the toughening effects were evaluated and the toughening mechanism was investigated.The thermal stability of the cured resin was studied by thermogravimetric analysis(TG).The results show that the impact strength of CTBN modified EP increases greatly, the tensile shear strength increases and the thermal stability improves, but the bending strength and bending modulus decrease.%以2-乙基-4-甲基咪唑作为固化剂,运用红外光谱对端羧基丁腈橡胶(CTBN)增韧改性环氧树脂(EP)的预聚反应和固化反应进行分析.通过测试改性环氧树脂固化物的冲击强度、弯曲强度和拉伸剪切强度评价其增韧效果,探讨其增韧机理,并通过热失重(TG)分析固化物的热稳定性能.结果表明:CTBN改性EP后,树脂的冲击强度明显提高,拉伸剪切强度有所提高,热稳定性能提高,但弯曲强度和弯曲模量有所降低.

  19. Evaluation of the bond strength of different adhesive agents to a resin-modified calcium silicate material (TheraCal LC).

    Science.gov (United States)

    Karadas, Muhammed; Cantekin, Kenan; Gumus, Husniye; Ateş, Sabit Melih; Duymuş, Zeynep Yesil

    2016-09-01

    This study evaluated the bond strength of different adhesive agents to TheraCal LC and mineral trioxide aggregate (MTA) and examined the morphologic changes of these materials with different surface treatments. A total of 120 specimens, 60 of MTA Angelus (AMTA), and 60 of TheraCal LC, were prepared and divided into six subgroups according to the adhesive agent used; these agents included Scotchbond Multipurpose, Clearfil SE Bond, Clearfil Protect Bond, Clearfil S(3) Bond, OptiBond All-in-One, and G-aenial Bond. After application of adhesive agents, Filtek Z250 composite resin was placed onto the specimens. Shear bond strengths were measured using a universal testing machine, followed by examination of the fractured surfaces. The surface changes of the specimens were observed using scanning electron microscopy. Data were compared by two-way analysis of variance. Although no significant differences were found among the bond strengths of different adhesives to AMTA (p = 0.69), a significant difference was found in terms of bond strengths of different adhesives to the TheraCal LC surface (p TheraCal LC compared to the bond with other adhesives. TheraCal LC bonded significantly more strongly than AMTA regardless of the adhesive agents tested. Resin-modified calcium silicate showed higher bond strength than AMTA in terms of the composite bond to these materials with different bonding systems. On the other hand, the highest shear bond-strength values were found for composite bonds with the combination of TheraCal LC and the total-etch adhesive system. SCANNING 38:403-411, 2016. © 2015 Wiley Periodicals, Inc.

  20. Comparative evaluation of microleakage of conventional and modifications of glass ionomer cement in primary teeth: An in vitro study

    Directory of Open Access Journals (Sweden)

    A S Shruthi

    2015-01-01

    Full Text Available Aims: The aim of the present study was to evaluate the microleakage among conventional, resin modified glass ionomer cements (GIC, and compomer cements in primary teeth. Materials and Methods: Forty-five over retained non carious primary molars beyond exfoliation time were collected and randomly divided into three groups (n = 15. Group A: GC Fuji II; Group B: Vitremer; Group C: Compoglass F. A standard Class V cavity was prepared on the buccal surface of each tooth with no mechanical retention and restored accordingly. Then all the samples were subjected to thermocycling for 250 cycles at different temperatures and covered with nail varnish. Later, samples were immersed in 0.5% methylene blue dye for 24 h. Teeth were sectioned buccolingually through the center of the restoration and studied under a stereomicroscope for dye penetration. Data obtained were analyzed using Kruskal-Wallis ANOVA and Mann-Whitney U-test. Results: Samples restored with vitremer showed comparatively higher microleakage than the samples in other groups. However, overall there were no significant difference between the microleakage scores of the samples in all three groups (P > 0.05. Conclusion: It can be concluded that none of the three GICs was free from microleakage. Hence, further research is required to compare microleakage of the newer material.

  1. A review of glass-ionomers: From conventional glass-ionomer to bioactive glass-ionomer

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2013-01-01

    Full Text Available Materials used in the body, especially the materials used in various oral cavity regions should be stable and passive without any interactions with the body tissues or fluids. Dental amalgam, composite resins and dental cements are the materials of choice with such properties. The first attempts to produce active materials, which could interact with the human body tissues and fluids were prompted by the concept that fluoride-releasing materials exert useful effects in the body. The concept of using the "smart" materials in dentistry has attracted a lot of attention in recent years. Conventional glass-ionomer (GI cements have a large number of applications in dentistry. They are biocompatible with the dental pulp to some extent. GI is predominantly used as cements in dentistry; however, they have some disadvantages, the most important of which is lack of adequate strength and toughness. In an attempt to improve the mechanical properties of the conventional GI, resin-modified glass-ionomers have been marketed, with hydrophilic monomers, such as hydroxyethyl methacrylated (HEMA. Some recent studies have evaluated GI with bioactive glass in its structure to validate the claims that such a combination will improve tooth bioactivity, regeneration capacity and restoration. There is ever-increasing interest in the application of bioactive materials in the dental field in an attempt to remineralize affected dentin. The aim of this review article is to evaluate these materials and their characteristics and applications.

  2. Effects of etching and adhesive applications on the bond strength between composite resin and glass-ionomer cements

    Directory of Open Access Journals (Sweden)

    Tijen Pamir

    2012-12-01

    Full Text Available OBJECTIVE: This study determined the effects of various surface treatment modalities on the bond strength of composite resins to glass-ionomer cements. MATERIAL AND METHODS: Conventional (KetacTM Molar Quick ApplicapTM or resin-modified (PhotacTM Fil Quick AplicapTM glass-ionomer cements were prepared. Two-step etch-rinse & bond adhesive (AdperTM Single Bond 2 or single-step self-etching adhesive (AdperTM PromptTM L-PopTM was applied to the set cements. In the etch-rinse & bond group, the sample surfaces were pre-treated as follows: (1 no etching, (2 15 s of etching with 35% phosphoric acid, (3 30 s of etching, and (4 60 s of etching. Following the placement of the composite resin (FiltekTM Z250, the bond strength was measured in a universal testing machine and the data obtained were analyzed with the two-way analysis of variance (ANOVA followed by the Tukey's HSD post hoc analysis (p=0.05. Then, the fractured surfaces were examined by scanning electron microscopy. RESULTS: The bond strength of the composite resin to the conventional glass-ionomer cement was significantly lower than that to the resin-modified glass-ionomer cement (p0.05. However, a greater bond strength was obtained with 30 s of phosphoric acid application. CONCLUSIONS: The resin-modified glass-ionomer cement improved the bond strength of the composite resin to the glass-ionomer cement. Both etch-rinse & bond and self-etching adhesives may be used effectively in the lamination of glass-ionomer cements. However, an etching time of at least 30 s appears to be optimal.

  3. Structural iron (II of basaltic glass as an energy source for Zetaproteobacteria in an abyssal plain environment, off the Mid Atlantic Ridge

    Directory of Open Access Journals (Sweden)

    Pauline Audrey Henri

    2016-01-01

    Full Text Available To explore the capability of basaltic glass to support the growth of chemosynthetic microorganisms, complementary in situ and in vitro colonization experiments were performed. Microbial colonizers containing synthetic tholeitic basaltic glasses, either enriched in reduced or oxidized iron, were deployed off-axis from the Mid Atlantic Ridge on surface sediments of the abyssal plain (35°N; 29°W. In situ microbial colonization was assessed by sequencing of the 16S rRNA gene and basaltic glass alteration was characterized using Scanning Electron Microscopy, micro-X-ray Absorption Near Edge Structure at the Fe-K-edge and Raman microspectroscopy. The colonized surface of the reduced basaltic glass was covered by a rind of alteration made of iron-oxides trapped in a palagonite-like structure with thicknesses up to 150 µm. The relative abundance of the associated microbial community was dominated (39% of all reads by a single operational taxonomic unit (OTU that shared 92% identity with the iron-oxidizer Mariprofundus ferrooxydans PV-1. Conversely, the oxidized basaltic glass showed the absence of iron-oxides enriched surface deposits and correspondingly there was a lack of known iron-oxidizing bacteria in the inventoried diversity. In vitro, a similar reduced basaltic glass was incubated in artificial seawater with a pure culture of the iron-oxidizing M. ferrooxydans DIS-1 for 2 weeks, without any additional nutrients or minerals. Confocal Laser Scanning Microscopy revealed that the glass surface was covered by twisted stalks characteristic of this iron-oxidizing Zetaproteobacteria. This result supported findings of the in situ experiments indicating that the Fe(II present in the basalt was the energy source for the growth of representatives of Zetaproteobacteria in both the abyssal plain and the in vitro experiment. In accordance, the surface alteration rind observed on the reduced basaltic glass incubated in situ could at least partly result from

  4. The effect of Coca-Cola and fruit juices on the surface hardness of glass-ionomers and 'compomers'.

    Science.gov (United States)

    Aliping-McKenzie, M; Linden, R W A; Nicholson, J W

    2004-11-01

    The interaction of tooth-coloured dental restorative materials (a conventional glass-ionomer, two resin-modified glass-ionomers and two compomers) with acidic beverages has been studied with the aim of investigating how long-term contact affects solution pH and specimen surface hardness. For each material (ChemFil Superior, ChemFlex, Vitremer Core Build-Up/Restorative, Fuji II LC, Dyract AP and F2000) disc-shaped specimens were prepared and stored in sets of six in the following storage media: 0.9% NaCl (control), Coca-Cola, apple juice and orange juice. After time intervals of 1 day, 1 week, 1 month, 3 months, 4 months, 6 months and 1 year, solution pH and Vickers Hardness Number were determined for each individual specimen. Differences were analysed by anova followed by Student-Newman-Keuls post hoc analysis. All materials were found to reduce the pH of the 0.9% NaCl, but to increase the pH of the acidic beverages. The conventional glass-ionomers dissolved completely in apple juice and orange juice, but survived in Coca-Cola, albeit with a significantly reduced hardness after 1 year. The other materials survived in apple juice and orange juice, but showed greater reductions in surface hardness in these beverages than in Coca-Cola. Fruit juices were thus shown to pose a greater erosive threat to tooth coloured materials than Coca-Cola, a finding which is similar to those concerning dentine and enamel towards these drinks.

  5. Clinical Evaluation of Restorative Materials in Primary Teeth Class II Lesions.

    Science.gov (United States)

    Sengul, F; Gurbuz, T

    2015-01-01

    The aim of this study was to evaluate clinical success of primary teeth class II lesions restored with different restorative materials [Hybrid Composite Resin (HCR), Resin Modified Glass Ionomer Cement (RMGIC), compomer, and Giomer Composite Resin (GCR)] followed up for 24 months. This study was carried out on 146 primary molars of 41 children in the age range of 5-7 years. The class II lesions in primary molars of a patient were restored using different restorative materials. Restorations were evaluated according to FDI-criteria and their survival rates were determined. Data were analysed with Pearson chi-square, Kaplan-Meier and Wilcoxon (Breslow) tests (α = 0.05). The failure rates of restorative materials were as follows: compomer 33.3%, RMGIC 28.1%, HCR 22.5% and GCR 21.1%. While the functional failure was the most important factor in restorative material failure, RMGIC was the most successful material in terms of biological evaluation criterion and GCR had the longest survival rate.

  6. Study on the spin crossover transition and glass transition for Fe(II) complex film, [Fe(II)(H-triazole){sub 3}]-Nafion, by means of Moessbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nakamoto, Akio; Kamebuchi, Hajime, E-mail: cc106909@mail.ecc.u-tokyo.ac.jp [University of Tokyo, Graduate School of Arts and Sciences (Japan); Enomoto, Masaya [Tokyo University of Science, Department of Chemistry, Faculty of Science Division I (Japan); Kojima, Norimichi [University of Tokyo, Graduate School of Arts and Sciences (Japan)

    2012-03-15

    [Fe(II)(H-trz){sub 3}]-Nafion (trz = triazole) is a transparent spin crossover complex film, where the spin crossover transition between the low-spin (S = 0) and the high-spin (S = 2) states takes place between 225 K and 300 K. In this film, two doublets corresponding to the low-spin and high-spin states were observed in the {sup 57}Fe Moessbauer spectra, reflecting the spin crossover transition. From the analysis of {sup 57}Fe Moessbauer spectra, the Debye temperatures of the low-spin and high-spin sites were estimated at 185 K and 176 K, respectively, in the temperature range between 10 K and 150 K. In this film, the total intensity of the Moessbauer spectra corresponding to the low-spin and high-spin sites drastically decreases above 200 K, reflecting the glass transition of Nafion, where the lattice vibration of [Fe(H-trz){sub 3}]{sub n}{sup 2n+} is softened just as in solution due to micro-Brown motion of the segment of Nafion polymer membrane.

  7. Evaluation of the Effects of Different Mouthrinses on the Color Stability of One Type of Glass Ionomer, Compomer and Giomer

    Directory of Open Access Journals (Sweden)

    Shaghayegh Razavi

    2015-12-01

    Full Text Available Objectives: The aim of this study was to evaluate the effect of four commercially available mouthrinses on the color stability of one type of glass ionomer, giomer and compomer. Method: 60 disc-shaped specimens, 180 in total (7*2mm, fabricated from each of the following materials: A resin modified glass ionomer Fuji II LC (GC International Corp, a giomer Beautifil II (SHOFU INC and a compomer Ionosit (DMG. All specimens were stored in artificial saliva at 37˚C for 24 hours in an incubator. The initial colour value (L*,a*,b* were recorded with spectrophotometer according to CIELAB scale. After baseline evaluation, the specimens were divided into five subgroups, according to the testing and control storage solutions (n=12. Randomly selected specimens from each material were immersed in 20 ml of the treatment solutions (Oral-B Pro Expert, Listerine, Colgate Plax, Irasha at 37˚c for 24 hours. Each specimen was then subjected to second color measurement. The collected data was statistically analyzed using two-way analysis of variance (ANOVA and Tukey’s HSD at a significance level of 0.05. Results: All samples displayed color changes after immersion in the mouthrinses. The observed color difference showed that mouthrinses have a significant effect on the color shift of tested materials. A significant interaction was found between the materials and the mouthrinses. Overall, discoloration with all mouthrinses was significant when compared to the control specimens stored in artificial saliva. Oral-B induced the highest level of discoloration (ΔE*= 11.62 in Compomer and the least discoloration was found with Irsha (ΔE*= 1.47 in RMGI. Conclusions: All tested restorative materials showed a color shift after immersion in mouthrinses, amongst which compomer displayed the highest change. Discolorations were clinically perceptible in most of the cases. Thus it can be concluded that daily use of mouthrinses increases the stainability of tested materials.

  8. Evaluation of the Effects of Different Mouthrinses on the Color Stability of One Type of Glass Ionomer, Compomer and Giomer

    Directory of Open Access Journals (Sweden)

    Shaghayegh Razavi

    2016-03-01

    Full Text Available Objectives: The aim of this study was to evaluate the effect of four commercially available mouthrinses on the color stability of one type of glass ionomer, giomer and compomer. Method: 60 disc-shaped specimens, 180 in total (7*2mm, fabricated from each of the following materials: A resin modified glass ionomer Fuji II LC (GC International Corp, a giomer Beautifil II (SHOFU INC and a compomer Ionosit (DMG. All specimens were stored in artificial saliva at 37˚C for 24 hours in an incubator. The initial colour value (L*,a*,b* were recorded with spectrophotometer according to CIELAB scale. After baseline evaluation, the specimens were divided into five subgroups, according to the testing and control storage solutions (n=12. Randomly selected specimens from each material were immersed in 20 ml of the treatment solutions (Oral-B Pro Expert, Listerine, Colgate Plax, Irasha at 37˚c for 24 hours. Each specimen was then subjected to second color measurement. The collected data was statistically analyzed using two-way analysis of variance (ANOVA and Tukey’s HSD at a significance level of 0.05. Results: All samples displayed color changes after immersion in the mouthrinses. The observed color difference showed that mouthrinses have a significant effect on the color shift of tested materials. A significant interaction was found between the materials and the mouthrinses. Overall, discoloration with all mouthrinses was significant when compared to the control specimens stored in artificial saliva. Oral-B induced the highest level of discoloration (ΔE*= 11.62 in Compomer and the least discoloration was found with Irsha (ΔE*= 1.47 in RMGI. Conclusions: All tested restorative materials showed a color shift after immersion in mouthrinses, amongst which compomer displayed the highest change. Discolorations were clinically perceptible in most of the cases. Thus it can be concluded that daily use of mouthrinses increases the stainability of tested materials.

  9. Evaluation and comparison of the effect of different surface preparations on bond strength of glass ionomer cement with nickel-chrome metal-ceramic alloy: a laboratory study.

    Science.gov (United States)

    Hasti, Kalpana; Jagadeesh, H G; Patil, Narendra P

    2011-03-01

    Retention of fixed partial dentures is mostly dependent upon the bond between metal and cement as well as cement and tooth structure. However, most of the time clinical failure of bond has been observed at metal and cement interface. The treatment of metal surface, prior to luting, plays a crucial role in bonding cement with the metal. This study is conducted to evaluate and compare the effect of different surface preparations on the bond strength of resin-modified glass ionomer cement with nickel-chromium metal ceramic alloy. Fifty caries-free extracted molar teeth were made flat until the dentin of the occlusal surface was exposed. After fabrication of the wax patterns and subsequent castings, the castings were subjected to porcelain firing cycles. The nickel-chromium metal ceramic alloy discs were also divided into five groups and subjected to various surface treatments: (1) Unsandblasted (U), (2) sandblasted (S), (3) sandblasted and treated with 10% aqueous solution of KMnO4 (SK), (4) unsandblasted and roughened with diamond abrasive points (UD) and (5) unsandblasted and roughened with diamond abrasive points and treated with 10% aqueous solution of KMnO(4) (UDK). After surface treatments, the castings were cemented using Fuji PLUS encapsulated resin-modified glass ionomer cement. The obtained values of all the groups were subjected to statistical analysis for Tensile and Shear bond strength. Different surface treatments of the metal affects the bond strength values of resin-modified glass ionomer cement when used as luting agent.

  10. Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials

    Directory of Open Access Journals (Sweden)

    Shefali Sawani

    2014-01-01

    Full Text Available Background: Evaluation of microleakage is important for assessing the success of new restorative materials and methods. Aim and Objectives: Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials. Materials and Methods: Standardized mesi-occlusal (MO and distoocclusal (DO Class II tooth preparations were preparedon 53 molars and samples were randomly divided into six experimental groups and one control group for restorations. Group 1: Open-Sandwich technique (OST with flowable composite at the gingival seat. Group 2: OST with resin-modified glass ionomer cement (RMGIC at the gingival seat. Group 3: Closed-Sandwich technique (CST with flowable composite at the pulpal floor and axial wall. Group 4: CST with RMGIC at the pulpal floor and axial wall. Group 5: OST with flowable composite at the pulpal floor, axial wall, and gingival seat. Group 6: OST with RMGIC at the pulpal floor, axial wall, and gingival seat. Group 7: Control - no lining material, centripetal technique only. After restorations and thermocycling, apices were sealed and samples were immersed in 0.5% basic fuchsin dye. Sectioning was followed by stereomicroscopic evaluation. Results: Results were analyzed using Post Hoc Bonferroni test (statistics is not a form of tabulation. Cervical scores of control were more than the exprimental groups (P 0.05. Conclusion: Class II composite restorations with centripetal build-up alone or when placed with CST reduces the cervical microleakage when compared to OST.

  11. Intrapulpal Thermal Changes during Setting Reaction of Glass Carbomer® Using Thermocure Lamp

    Science.gov (United States)

    Tosun, Gül

    2016-01-01

    Objectives. To measure the temperature increase induced during thermocure lamp setting reaction of glass carbomer and to compare it with those induced by visible light curing of a resin-modified glass ionomer and a polyacid-modified composite resin in primary and permanent teeth. Materials and Methods. Nonretentive class I cavities were prepared in extracted primary and permanent molars. Glass carbomer (GC) was placed in the cavity and set at 60°C for 60 sn using a special thermocure lamp. Resin-modified glass ionomer (RMGIC) and polyacid-modified composite resin (PMCR) were placed in the cavities and polymerized with an LED curing unit. Temperature increases during setting reactions were measured with a J-type thermocouple wire connected to a data logger. Data were examined using two-way analysis of variance and Tukey's honestly significant difference tests. Results. The use of GC resulted in temperature changes of 5.17 ± 0.92°C and 5.32 ± 0.90°C in primary and permanent teeth, respectively (p > 0.05). Temperature increases were greatest in the GC group, differing significantly from those in the PMCR group (p < 0.05). Conclusion. Temperature increases during polymerization and setting reactions of the materials were below the critical value in all groups. No difference was observed between primary and permanent teeth, regardless of the material used. PMID:28097136

  12. Clinical evaluation of glass-ionomer cement restorations Avaliação clínica de restaurações de cimento de ionômero de vidro

    OpenAIRE

    Martin John Tyas

    2006-01-01

    This article mentions the general structure, properties and clinical performance of conventional and resin-modified glass-ionomer cements, focusing on adhesion, caries inhibition effect and recommendations of their use.Este artigo menciona a estrutura geral, propriedades e performance clínica de cimentos de ionômero de vidro convencionais e modificados por resina, enfocando propriedades como adesão, efeito anti-cariogênico e recomendações de uso.

  13. Clinical evaluation of glass-ionomer cement restorations Avaliação clínica de restaurações de cimento de ionômero de vidro

    Directory of Open Access Journals (Sweden)

    Martin John Tyas

    2006-01-01

    Full Text Available This article mentions the general structure, properties and clinical performance of conventional and resin-modified glass-ionomer cements, focusing on adhesion, caries inhibition effect and recommendations of their use.Este artigo menciona a estrutura geral, propriedades e performance clínica de cimentos de ionômero de vidro convencionais e modificados por resina, enfocando propriedades como adesão, efeito anti-cariogênico e recomendações de uso.

  14. A measurement of the change of the energy dependence of the total cross-section of phase II solid methane from confinement in aerogel glass

    Energy Technology Data Exchange (ETDEWEB)

    Yan, H., E-mail: haiyan@umail.iu.ed [Department of Physics, Indiana University/IUCF, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States); Baxter, D.V.; Jiang, C.Y.; Kaiser, H.; Shin, Y.C.; Snow, W.M.; Tong, X. [Department of Physics, Indiana University/IUCF, 2401 Milo B. Sampson Lane, Bloomington, IN 47408 (United States)

    2011-02-15

    We report measurements of the energy dependence of the total neutron scattering cross-section of CH{sub 4} both in bulk and confined in aerogel glass for neutron energies between {approx}0.3and {approx}200 meV. Solid CH{sub 4} in phase II is an effective slow neutron moderation medium. Aerogel glass is one example of a broad class of disordered porous media with a large internal surface area. Many disordered materials possess excess low energy modes which have been seen in neutron scattering, and it is known that the confinement of materials inside porous media can produce modifications of the thermodynamic and excitation properties large enough to influence the neutron scattering cross-section. Our measurement shows that the confinement of the methane in pores of aerogel modifies the energy dependence total cross-section relative to bulk CH{sub 4}.

  15. Geochemistry of the 1989-1990 eruption of redoubt volcano: Part II. Evidence from mineral and glass chemistry

    Science.gov (United States)

    Swanson, S.E.; Nye, C.J.; Miller, T.P.; Avery, V.F.

    1994-01-01

    Early stages (December 1989) of the 1989-1990 eruption of Redoubt Volcano produced two distinct lavas. Both lavas are high-silica andesites with a narrow range of bulk composition (58-64 wt.%) and similar mineralogies (phenocrysts of plagioclase, hornblende, augite, hypersthene and FeTi oxides in a groundmass of the same phases plus glass). The two lavas are distinguished by groundmass glass compositions, one is dacitic and the other rhyolitic. Sharp boundaries between the two glasses in compositionally banded pumices, lack of extensive coronas on hornblende phenocrysts, and seismic data suggest that a magma-mixing event immediately preceeded the eruption in December 1989. Textural disequilibrium in the phenocrysts suggests both magmas (dacitic and rhyolitic glasses) had a mixing history prior to their interaction and eruption in 1989. Sievey plagioclase and overgrowths of magnetite on ilmenite are textures that are at least consistent with magma mixing. The presence of two hornblende compositions (one a high-Al pargasitic hornblende and one a low-Al magnesiohornblende) in both the dacitic and rhyolitic groundmasses indicates a mixing event to yield these two amphibole populations prior to the magma mixing in December 1989. The pargasitic hornblende and the presence of Ca-rich overgrowths in the sievey zones of the plagioclase together indicate at least one component of this earlier mixing event was a mafic magma, either a basalt or a basaltic andesite. Eruptions in 1990 produced only andesite with a rhyolitic groundmass glass. Glass compositions in the 1990 andesite are identical to the rhyolitic glass in the 1989 andesite. Cognate xenoliths from the magma chamber (or conduit) are also found in the 1990 lavas. Magma mixing probably triggered the eruption in 1989. The eruption ended when this rather viscous (rhyolitic groundmass glass, magma capable of entraining sidewall xenoliths) magma stabalized within the conduit. ?? 1994.

  16. Enhancement in Mode II Interlaminar Fracture Toughness at Cryogenic Temperature of Glass Fiber/Epoxy Composites through Matrix Modification by Carbon Nanotubes and n-Butyl Glycidyl Ether

    Directory of Open Access Journals (Sweden)

    Yu Liu

    2015-01-01

    Full Text Available A typical diglycidyl ether of bisphenol-F (DGEBF/diethyl toluene diamine (DETD epoxy system modified by multiwalled carbon nanotubes (MWCNTs and a reactive aliphatic diluent named n-butyl glycidyl ether (BGE was used as the matrix for glass fiber composites. The glass fiber (GF reinforced composites based on the unmodified and modified epoxy matrices were prepared by the hand lay-up hot-press process. Mode II interlaminar fracture toughness at both room temperature (RT and cryogenic temperature (77 K of the GF reinforced epoxy composites was investigated to examine the effect of the matrix modification. The result showed that the introduction of MWCNTs and BGE at their previously reported optimal contents led to the remarkable enhancement in mode II interlaminar fracture toughness of the composites. Namely, the 22.9% enhancement at RT and the 31.4% enhancement at 77 K were observed for mode II interlaminar fracture toughness of the fiber composite based on the optimally modified epoxy matrix by MWCNTs and BGE compared to the unmodified case.

  17. Evaluation of Gingival Microleakage in Class II Composite Restorations with Different Lining Techniques: An In Vitro Study

    Directory of Open Access Journals (Sweden)

    Vedavathi Bore Gowda

    2015-01-01

    Full Text Available Aim. To compare the microleakage in class II composite restorations without a liner/with resin modified glass ionomer and flowable composite liner. Method. Forty standardized MO cavities were prepared on human permanent mandibular molars extracted for periodontal reasons and then divided into 4 groups of ten specimens. The cavity preparations were etched, rinsed, blot dried, and light cured and Adper Single Bond 2 is applied. Group 1 is restored with Filtek P60 packable composite in 2 mm oblique increments. Group 2 is precure group where 1 mm Filtek Z350 flowable liner is applied and light cured for 20 sec. Group 3 is the same as Group 2, but the liner was cocured with packable composite. In Group 4, 1 mm RMGIC, Fuji Lining LC is applied and cured for 20 sec. All the teeth were restored as in Group 1. The specimens were coated with nail varnish leaving 1 mm around the restoration, subjected to thermocycling, basic fuchsin dye penetration, sectioned mesiodistally, and observed under a stereomicroscope. Results. The mean leakage scores of the individual study groups were Group 1 (33.40, Group 2 (7.85, Group 3 (16.40, and Group 4 (24.35. Group 1 without a liner showed maximum leakage. Flowable composite liner precured was the best.

  18. Chronostratigraphy of the Trenton Group and Utica Shale, Pt. II: Stratigraphic correlations using Ordovician glasses in K-bentonites

    Energy Technology Data Exchange (ETDEWEB)

    Delano, J.W.; Tice, S. (State Univ. of New York, Albany, NY (United States). Dept. of Geological Sciences); Mitchell, C.E.; Goldman, D. (State Univ. of New York, Buffalo, NY (United States). Dept. of Geology); Samson, S.D. (Syracuse Univ., NY (United States). Dept. of Geology)

    1992-01-01

    Rhyolitic glasses in the form of pristine melt inclusions that occur within quartz phenocrysts are being used for the geochemical fingerprinting of Ordovician K-bentonites in the northern Appalachian Basin. These melt inclusions are samples of pre-eruptive magma that became trapped during phenocryst growth in the deep crustal magma chambers. Plinian eruptions led to quenching of the enclosed rhyolitic magma to form glass when the quartz phenocrysts were blasted into the atmosphere. Preservation of this Ordovician glass is due to its being hermetically sealed within a mineral (quartz) that is resistant to weathering and diagenetic alteration. Chemical compositions of glasses in four Ordovician K-bentonites from the Mohawk Valley of New York State have been acquired using high-precision, electron microprobe analyses. The elements Mg, Cl, Ca, Ti, and Fe are often diagnostic. The accompanying figure illustrates one combination of elements that is effective in distinguishing K-bentonites, which are not stratigraphically equivalent. These K-bentonites were selected to test competing chronostratigraphies of the northern Appalachian Basin and indicate problems with the model by Cisne et al.

  19. First evidence of the presence of chitin in skeletons of marine sponges. Part II. Glass sponges (Hexactinellida: Porifera).

    Science.gov (United States)

    Ehrlich, Hermann; Krautter, Manfred; Hanke, Thomas; Simon, Paul; Knieb, Christiane; Heinemann, Sascha; Worch, Hartmut

    2007-07-15

    Sponges (Porifera) are presently gaining increased scientific attention because of their secondary metabolites and specific skeleton structures. In contrast to demosponges, whose skeletons are formed from biopolymer spongin, glass sponges (hexactinellids) possess silica-organic composites as the main natural material for their skeletal fibres. Chitin has a crystalline structure and it constitutes a network of organized fibres. This structure confers rigidity and resistance to organisms that contain it, including monocellular (yeast, amoeba, diatoms) and multicellular (higher fungi, arthropods, nematodes, molluscs) organisms. In contrast to different marine invertebrates whose exoskeletons are built of chitin, this polysaccharide has not been found previously as an endogenous biopolymer within glass sponges (Hexactinellida). We hypothesized that glass sponges, which are considered to be the most basal lineage of multicellular animals, must possess chitin. Here, we present a detailed study of the structural and physico-chemical properties of skeletal fragments of the glass sponge Farrea occa. We show that these fibres have a layered design with specific compositional variations in the chitin/silica composite. We applied an effective approach for the demineralization of glass sponge skeletal formations based on an etching procedure using alkali solutions. The results show unambiguously that alpha-chitin is an essential component of the skeletal structures of Hexactinellida. This is the first report of a silica-chitin's composite biomaterial found in nature. From this perspective, the view that silica-chitin scaffolds may be key templates for skeleton formation also in ancestral unicellular organisms, rather than silica-protein composites, emerges as a viable alternative hypothesis.

  20. Investigation of zinc alkali pyrophosphate glasses. Part II: Local and medium range orders analysed by 1D/2D NMR

    Energy Technology Data Exchange (ETDEWEB)

    Rajbhandari, P. [UCCS UMR-CNRS 8181, Université de Lille1, Villeneuve d' Ascq (France); Chen, Y. [LASIR UMR-CNRS 8516, Université de Lille1, Villeneuve d' Ascq (France); Doumert, B. [IMMCL CNRS-FR2638, Université de Lille1, Villeneuve d' Ascq (France); Montagne, L. [UCCS UMR-CNRS 8181, Université de Lille1, Villeneuve d' Ascq (France); Tricot, G., E-mail: gregory.tricot@univ-lille1.fr [UCCS UMR-CNRS 8181, Université de Lille1, Villeneuve d' Ascq (France); LASIR UMR-CNRS 8516, Université de Lille1, Villeneuve d' Ascq (France)

    2015-04-01

    The structure of the (66-x)ZnO-xNa{sub 2}O-33.4P{sub 2}O{sub 5} composition line, selected for the development of low-Tg and stable glasses, has been investigated by 1D/2D NMR spectroscopy. If standard 1D {sup 31}P MAS-NMR experiments give access to the Q{sup n} speciation and show the presence of Q{sup 0}, Q{sup 1} and Q{sup 2} sites within the glass structure, application of the homonuclear through-space correlation technique ({sup 31}P DQ-SQ) allows for a more accurate description of the phosphate units. Clear distinction between the Q{sup 1} sites involved in dimmers or in longer chains has been derived from 2D NMR correlation maps and leads to the re-assignment of Q{sup 1} into Q{sup 1,1} and Q{sup 1,2} species. {sup 23}Na and {sup 23}Na({sup 31}P) REDOR MAS-NMR experiments have been used to analyse the Na{sup +} ions distribution and its interaction with the phosphate network. {sup 67}Zn static NMR experiments, performed at very high field, were carried out and suggest a constant Zn{sup 2+} coordination state all along the composition line. The results have been used to discuss the impact of the Zn{sup 2+}/Na{sup +} ratio on the extent of disorder within the glass network expressed in terms of Q{sup n} dismutation equilibrium constant and phosphate chain length distribution. - Highlights: • Structure of zinc alkali pyrophosphate glasses have been analysed by 1D/2D NMR. • 2D {sup 31}P experiments allow to separate Q{sup 1,1} and Q{sup 1,2} species. • {sup 67}Zn static NMR shows a constant signal all along the composition line.

  1. A method for making a glass supported system, such glass supported system, and the use of a glass support therefor

    NARCIS (Netherlands)

    Unnikrishnan, S.; Jansen, Henricus V.; Berenschot, Johan W.; Fazal, I.; Louwerse, M.C.; Mogulkoc, B.; Sanders, Remco G.P.; de Boer, Meint J.; Elwenspoek, Michael Curt

    2008-01-01

    The invention relates to a method for making a glass supported micro or nano system, comprising the steps of: i) providing a glass support; ii) mounting at least one system on at least one glass support; and iii) bonding the system to the glass support, such that the system is circumferentially

  2. Cloth catalysts in water denitrification. II. Removal of nitrates using Pd-Cu supported on glass fibers

    OpenAIRE

    Matatov-Meytal, Yu.; Barelko, V.; Yuranov, I.; Kiwi-Minsker, L.; Renken, A.; Sheintuch, M.

    2001-01-01

    The use of glass fibers in the form of woven cloth (GFC), as a new type of catalytic support, was studied for the reduction of aqueous nitrate solutions using a Pd/Cu–GFC catalyst. The activity (per gram Pd) and selectivity to nitrogen were found to be comparable with those found for Pd–Cu catalysts supported on the other carriers. The maximal initial removal activity was found for a catalyst with a Pd/(Pd+Cu) ratio of 0.81. The corresponding activity was 0.7 mmol min-1 (gPd)-1, and the selec...

  3. Preparation and properties of bisphenol-F based boron-phenolic resin/modified silicon nitride composites and their usage as binders for grinding wheels

    Science.gov (United States)

    Lin, Chun-Te; Lee, Hsun-Tsing; Chen, Jem-Kun

    2015-03-01

    In this study, phenolic resins based on bisphenol-F (BPF) were synthesized. Besides, ammonium borate was added in the synthesis process of BPF to form the bisphenol-F based boron-phenolic resins (B-BPF). The glass transition temperature, thermal resistance, flexural strength and hardness of B-BPF are respectively higher than those of BPF. This is due to the presence of new cross-link Bsbnd O bonds in the B-BPF. In addition, the 3-aminopropyltriethoxysilane modified silicon nitride powders (m-SiN) were fully mixed with B-BPF to form the B-BPF/m-SiN composites. The thermal resistance and mechanical properties of the B-BPF/m-SiN are promoted by the well-dispersed and well-adhered m-SiN in these novel polymer/ceramics composites. The results of grinding experiments indicate that the grinding wheels bound by the B-BPF/m-SiN have better grinding quality than those bound by the BPF. Thus the B-BPF/m-SiN composites are better binding media than the BPF resins.

  4. A Histopathologic Study on Pulp Response to Glass Ionomer Cements in Human Teeth

    Directory of Open Access Journals (Sweden)

    M. Ghavamnasiri

    2005-12-01

    Full Text Available Statement of Problem: Despite the wide range of new dental materials, there is still a need for biomaterials demonstrating high biocompatibility, antimicrobial effects and ideal mechanical properties.Purpose: The aim of this study was to histologically evaluate the pulpal response to a conventional glass ionomer, a resin modified glass ionomer and a calcium hydroxide in human teeth.Materials and Methods: Fifty five deep class V cavities were prepared in premolars of 31 patients and were divided into 3 groups based on application of the following liners:resin modified glass ionomer (Vivaglass Liner, conventional glass ionomer (ChembondSuperior and calcium hydroxide (Dycal. After applying varnish, teeth were filled with amalgam. Each group was further divided into three subgroups according to time intervals of 7, 30 and 60 days. Teeth were then extracted and their crowns were fixed in formalin. Each sample was assessed microscopically for odontoblastic changes,inflammatory cell infiltration, reactionary dentin formation, remaining dentinal thickness and presence of microorganisms. Statistical analysis including Kruskal Wallis and Mann Whitney was carried out for comparison of mean ranks. (P=0.05.Results: In the Vivaglass Liner group, pulpal response was significantly higher on day 7 as compared to days 30 and 60 (P0.05. There was no correlation between pulpal responses with micro-organisms and remaining dentin thickness (P>0.05.Conclusion: According to the results of this study, light-cured glass ionomer as well as the other tested lining materials were determined to be biologically compatible with vital pulps in deep cavities of sound human teeth.

  5. Comparing the reinforcing effects of a resin modified glassionomer cement, Flowable compomer, and Flowable composite in the restoration of calcium hydroxide-treated immature roots in vitro

    OpenAIRE

    S Prathibha Rani

    2011-01-01

    One hundred and sixty human permanent central incisors were enlarged to a 120 file size after crown removal procedure to simulate immature teeth. The root canals were filled with calcium hydroxide and stored for 15 days (phase I), 30 days (phase II), 90 days (phase III), and 180 days (Phase IV). At the end of these selected time periods, calcium hydroxide was cleaned off the root canals of forty teeth that were randomly selected and obturated with gutta-percha points in the apical 2 mm of the...

  6. N-vinylpyrrolidone modified glass-ionomer resins for improved dental restoratives

    Science.gov (United States)

    Xie, Dong

    The studies described in this dissertation focus on improvement of mechanical properties of current glass-ionomer cements. Thermal properties and microstructures of the cements were correlated with their mechanical strengths. The first study evaluated mechanical properties of selected commercial glass-ionomer cements and examined their microstructures. The results showed that resin-modified glass-ionomer cements (RM GICs) exhibited much higher flexural (FS) and diametral tensile strengths (DTS), compared to conventional GICs (C GICs). In addition, they exhibited comparable compressive strength (CS), relatively low microhardness and less wear resistance than C GICs. The C GICs exhibited brittle behavior, whereas the RM GICs underwent substantial plastic deformation in compression. The mechanical properties of the GICs were closely related to their microstructures. Factors such as the density of the microstructure, the integrity of the interface between the glass particles and polymer matrix, particle size and the number and size of voids have important roles in determining the mechanical properties. The second study evaluated thermal properties of these GICs. The results showed that the RM GICs exhibited higher thermal transition temperatures than those of the C GICs, thermal expansion coefficients of these cements were close to those of human teeth, and the indentation creep of the RM GICs were higher than the C GICs. The third study explored and evaluated the effect of a water-soluble monomer, N-vinylpyrrolidone (NVP), on the performance of current C GICs, indicating a significant improvement in both mechanical and working properties. The fourth study demonstrated the process of determining the optimal molar ratio of the NVP-containing copolymers, using design of experiment. The results showed that the optimal molar ratio for these copolymers was 7:1:3 for poly(acrylic acid-co-itaconic acid-co-N-vinylpyrrolidone), based on the FS test. The molar ratio of 8:2:1 (AA

  7. Preparation and properties of bisphenol-F based boron-phenolic resin/modified silicon nitride composites and their usage as binders for grinding wheels

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chun-Te [Department of Polymer Engineering, National Taiwan University of Science and Technology, 43, Sec 4, Keelung Rd, Taipei 106, Taiwan (China); Lee, Hsun-Tsing [Department of Materials Science and Engineering, Vanung University, Chung-Li, Tao-Yuan, Taiwan (China); Chen, Jem-Kun, E-mail: jkchen@mail.ntust.edu.tw [Department of Polymer Engineering, National Taiwan University of Science and Technology, 43, Sec 4, Keelung Rd, Taipei 106, Taiwan (China)

    2015-03-01

    Highlights: • Bisphenol-F based boron-phenolic resins (B-BPF) with B−O bonds were synthesized. • The modified silicon nitride (m-SiN) was well dispersed and adhered in the B-BPF. • B-BPF/m-SiN composites have good thermal resistance and mechanical properties. • The grinding wheels bound by B-BPF/m-SiN have excellent grinding quality. - Abstract: In this study, phenolic resins based on bisphenol-F (BPF) were synthesized. Besides, ammonium borate was added in the synthesis process of BPF to form the bisphenol-F based boron-phenolic resins (B-BPF). The glass transition temperature, thermal resistance, flexural strength and hardness of B-BPF are respectively higher than those of BPF. This is due to the presence of new cross-link B−O bonds in the B-BPF. In addition, the 3-aminopropyltriethoxysilane modified silicon nitride powders (m-SiN) were fully mixed with B-BPF to form the B-BPF/m-SiN composites. The thermal resistance and mechanical properties of the B-BPF/m-SiN are promoted by the well-dispersed and well-adhered m-SiN in these novel polymer/ceramics composites. The results of grinding experiments indicate that the grinding wheels bound by the B-BPF/m-SiN have better grinding quality than those bound by the BPF. Thus the B-BPF/m-SiN composites are better binding media than the BPF resins.

  8. Influence of different restorative techniques on marginal seal of class II composite restorations

    Directory of Open Access Journals (Sweden)

    Sinval Adalberto Rodrigues Junior

    2010-02-01

    Full Text Available OBJECTIVE: To evaluate the gingival marginal seal in class II composite restorations using different restorative techniques. MATERIAL AND METHODS: Class II box cavities were prepared in both proximal faces of 32 sound human third molars with gingival margins located in either enamel or dentin/cementum. Restorations were performed as follows: G1 (control: composite, conventional light curing technique; G2: composite, soft-start technique; G3: amalgam/composite association (amalcomp; and G4: resin-modified glass ionomer cement/composite, open sandwich technique. The restored specimens were thermocycled. Epoxy resin replicas were made and coated for scanning electron microscopy examination. For microleakage evaluation, teeth were coated with nail polish and immersed in dye solution. Teeth were cut in 3 slices and dye penetration was recorded (mm, digitized and analyzed with Image Tool software. Microleakage data were analyzed statistically by non-parametric Kruskal-Wallis and Mann-Whitney tests. RESULTS: Leakage in enamel was lower than in dentin (p<0.001. G2 exhibited the lowest leakage values (p<0.05 in enamel margins, with no differences between the other groups. In dentin margins, groups G1 and G2 had similar behavior and both showed less leakage (p<0.05 than groups G3 and G4. SEM micrographs revealed different marginal adaptation patterns for the different techniques and for the different substrates. CONCLUSION: The soft-start technique showed no leakage in enamel margins and produced similar values to those of the conventional (control technique for dentin margins.

  9. Porous glasses for optical sensors

    Science.gov (United States)

    Dorosz, Dominik; Procyk, Bernadeta

    2006-03-01

    Microporous glasses from the Na II0-B II0 3-Si0 II system can be obtained by appropriate thermal and chemical treatment. During the thermal treatment the separation of the borate phase from the silicon skeleton has been occurred. The borates are in the form small drops joined to each other. In the course of chemical treatment the borates become leached in water, water solutions of acids or basis and the glass becomes porous. Microporous glasses may find application in many branches of science and engineering. The applications depend on the internal arrangement, size and shape of pores. These parameters may be in a wide range modified by a change of the chemical composition. The received porous glass was used as an element in optical fibre NO II sensor. The specific coloration reaction between organic reagents and NO II in the pores was occurred. It is possible to detection of 10-50 ppm NO II level.

  10. Short chain lead (II) alkanoates as ionic liquids and glass formers: A d.s.c., X-ray diffraction and FTIR spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Casado, F.J. [Departamento de Quimica Fisica, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain); Sanchez Arenas, A. [Seccion Departamental de Fisica Aplicada I, Facultad de Veterinaria (Spain); Garcia Perez, M.V. [Departamento de Quimica Fisica, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain); Redondo Yelamos, M.I. [Departamento de Quimica Fisica, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain); Lopez de Andres, S. [Departamento de Cristalografia, Facultad de Ciencias Geologicas, Universidad Complutense, 28040 Madrid (Spain); Cheda, J.A.R. [Departamento de Quimica Fisica, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain)]. E-mail: cheda@quim.ucm.es

    2007-03-15

    Three members of the lead (II) n-alkanoates (from etanoate to n-butanoate) have been synthesized, purified and studied by d.s.c., X-ray diffraction, and FTIR spectroscopy. Lead (II) acetate, propanoate, and butanoate present only a melting transition at T = (452.6, 398.2, and 346.5) K, with {delta}{sub f} H = (16.0, 13.1, and 15.6) kJ . mol{sup -1}, and {delta}{sub f} S (35.3, 32.8, and 45.1) J . mol{sup -1} . K{sup -1}, respectively. These temperature data correct to a great extent the historical values reported in the literature. These three members readily quench into a glass state. Their corresponding T {sub g} values are (314.4, 289.0, and 274.9) K, respectively, measured by d.s.c. at a heating rate of 5 K . min{sup -1}.

  11. Chemistry of glass-ionomer cements: a review.

    Science.gov (United States)

    Nicholson, J W

    1998-03-01

    Studies of the setting of glass-ionomer cements have been carried out for over twenty years, and there is now a considerable body of information concerning the steps that lead to the conversion of a freshly mixed cement paste into a solid, durable dental restorative. This paper reviews these studies, paying particular attention to more recent work. The conclusion is that glass-ionomers consist of interpenetrating networks of inorganic and organic components forming a matrix in which particles of unreacted glass are embedded. However, there remain uncertainties over aspects of the setting chemistry, for example over the role of (+)-tartaric acid in the setting reaction, and over the nature of the fluoride species which form during the reaction. The chemistry of resin-modified glass-ionomers is also discussed and shown to be more complex than that of the simple cements. The presence of the resin component slows down the ionic cure reaction of the conventional cement, and leads to both a significant exotherm and a set material capable of absorbing water reversibly. The paper concludes that the microstructure of the set cement depends completely on chemical composition and the kinetics of the setting process, and that an understanding of the setting chemistry of these materials is thus important for optimal clinical use.

  12. Long-term dentin retention of etch-and-rinse and self-etch adhesives and a resin-modified glass ionomer cement in non-carious cervical lesions

    DEFF Research Database (Denmark)

    Dijken, J.W.V. van; Pallesen, U.

    2008-01-01

    The aim of this study was to evaluate the clinical long-term retention to dentin of seven adhesive systems.......The aim of this study was to evaluate the clinical long-term retention to dentin of seven adhesive systems....

  13. Surface functionalization of bioactive glasses with natural molecules of biological significance, part II: Grafting of polyphenols extracted from grape skin

    Science.gov (United States)

    Zhang, Xin; Ferraris, Sara; Prenesti, Enrico; Verné, Enrica

    2013-12-01

    Polyphenols, as one of the most important family of phytochemicals protective substances from grape fruit, possess various biological activities and health-promoting benefits, for example: inhibition of some degenerative diseases, cardiovascular diseases and certain types of cancers, reduction of plasma oxidative stress and slowing aging. The combination of polyphenols and biomaterials may have good potential to reach good bioavailability and controlled release, as well as to give biological signaling properties to the biomaterial surfaces. In this research, conventional solvent extraction was developed for obtaining polyphenols from dry grape skins. The Folin&Ciocalteu method was used to determine the amount of total polyphenols in the extracts. Surface functionalization of two bioactive glasses (SCNA and CEL2) was performed by grafting the extracted polyphenols on their surfaces. The effectiveness of the functionalization was tested by UV spectroscopy, which analyzes the amount of polyphenols in the uptake solution (before and after functionalization) and on solid samples, and XPS, which analyzes the presence of phenols on the material surface.

  14. Glass sealing

    Energy Technology Data Exchange (ETDEWEB)

    Brow, R.K.; Kovacic, L.; Chambers, R.S. [Sandia National Labs., Albuquerque, NM (United States)

    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.

  15. 不同类型玻璃离子水门汀氟释放能力的比较分析%Different types of fluorine release of glass ionomer cements ability to comparative analysis

    Institute of Scientific and Technical Information of China (English)

    陈娜; 刘聪; 李行懿

    2012-01-01

    objective Selection and application of glass ionomer cement as a minimally invasive technique for the material, providing experimental basis. Method Use of ion chromatography method compared to the traditional GIC and resin modified GIC fluoride release capabilities, and complex and not containing fluorine resin composites on the fluoride release of the ability to undertake comparative, results Experiment 8 material fluoride release order is : China Qingpu > Fuji > Ketae-Molar> > FujiVIIFuji IXFuji II LC> II Beautifil ll > Z100 >. Containing no fluorine resin composite fluoride release from the 1D to the end of the experiment, the fluoride release was minor. Conclusion The different types of GIC material between the fluoride release and ability is different, choice of the fluoride release ability of the material is effective against caries.%目的:为选择和应用玻璃离子水门汀作为微创技术的材料,提供实验依据.方法:使用离子色谱仪比较传统型GIC和树脂改良型GIC氟释放的能力,并与复合体及不含氟复合树脂的氟释放能力进行比较.结果:实验当中8种材料的氟释放量顺序是:国产青浦> Fuji Ⅶ>Ketae-Molar> Fuji IX> Fuji ⅡLC> Fuji Ⅱ> Beautifil Ⅱ> Z100.不含氟复合树脂的释氟量从第1天至实验结束,氟释放量很轻微.结论:不同类型GIC材料之间氟释放量和能力不同,选择氟释放能力强的材料对抗龋是有效的.

  16. In vitro quantitative evaluation of marginal microleakage in class II restorations confected with a glass ionomer cement and two composite resins

    Directory of Open Access Journals (Sweden)

    BIJELLA Maria Fernanda Borro

    2001-01-01

    Full Text Available This study evaluated, in vitro, marginal microleakage in class II restorations confected with the glass ionomer cement Vitremer and with the composite resins Ariston pHc and P-60. The aims of the study were to assess the effect of thermocycling on those materials and to evaluate two methods utilized in the analysis of dye penetration. Sixty premolars divided in three groups were utilized; the teeth had proximal cavities whose cervical walls were located 1 mm below the cementoenamel junction. Half of the test specimens from each group underwent thermocycling; the other half remained in deionized water, at 37ºC. The specimens were immersed, for 24 hours, in a basic 0.5% fuchsin solution at 37ºC. For the analysis of microleakage, the specimens were sectioned in a mesio-distal direction, and the observation was carried out with the software Imagetools. The results were evaluated through the 2-way ANOVA and through the Tukey?s test. All groups presented marginal microleakage. The smallest values were obtained with Vitremer, followed by those obtained with the composite resins P-60 and Ariston pHc. There was no statistically significant difference caused by thermocycling, and the method of maximum infiltration was the best for detecting the extension of microleakage.

  17. Effects of three restorative techniques in the bond strength and nanoleakage at gingival wall of Class II restorations subjected to simulated aging.

    Science.gov (United States)

    de Mattos Pimenta Vidal, Cristina; Pavan, Sabrina; Briso, André Luiz Fraga; Bedran-Russo, Ana Karina

    2013-03-01

    To evaluate the effects of simulated aging in bond strength and nanoleakage of class II restorations using three different restorative techniques. Class II preparations (n = 12) were restored using: FS - composite resin Filtek Supreme Plus (3M/ESPE); RMGIC + FS - resin-modified glass ionomer cement Vitrebond Plus (3M/ESPE) + FS; and FFS + FS - flowable composite resin Filtek Supreme Plus Flowable (3M ESPE) + FS. The teeth were assigned into two groups: Control and Simulated Aging - Thermal/Mechanical cycling (3,000 cycles, 20-80 °C/500,000 cycles, 50 N). From each tooth, two slabs were assessed to microtensile bond strength test (μTBS) (MPa), and two slabs were prepared for nanoleakage assessment, calculated as penetration along the restoration margin considering the penetration length (%) and as the area of silver nitrate particle deposition (μm(2)). Data were analyzed by two-way analysis of variance (ANOVA) followed by Tukey's post hoc test (p < 0.05). FS presented the highest μTBS to dentin (22.39 ± 7.55 MPa) after simulated aging, while the presence of flowable resin significantly decreased μTBS (14.53 ± 11.65 MPa) when compared to no aging condition. Both control and aging groups of RMGIC + FS presented the highest values of silver nitrate penetration (89.90 ± 16.31 % and 97.14 ± 5.76 %) and deposition area (33.05 ± 12.49 and 28.08 ± 9.76 μm(2)). Nanoleakage was not affected by simulated aging. FS presented higher bond strength and lower nanoleakage and was not affected by simulated aging. Use of flowable resin compromised the bond strength after simulated aging. The use of an intermediate layer did not improve the dentin bond strength neither reduced nanoleakage at the gingival margins of class II restorations under simulated aging conditions.

  18. Análise elementar inorgânica e identificação de monômeros residuais orgânicos liberados por diferentes cimentos de ionômero de vidro

    OpenAIRE

    Marcia Hiromi Tanaka; Alberto Camilo Alécio; Danilo Luiz Flumignan; José Eduardo de Oliveira; Elisa Maria Aparecida Giro

    2013-01-01

    INTRODUCTION: Glass ionomer cements (GICs) release inorganic elements and organic residual monomers with the potential for deleterious effects on pulp cells. OBJECTIVE: To identify and quantify inorganic elements present in different GICs and released components from these materials in cell culture medium. MATERIAL AND METHOD: Samples of two resin-modified GICs for base/liner (Vitrebond and Fuji Lining LC), two resin-modified restorative GICs (Vitremer and Fuji II LC) and two conventional res...

  19. Waterborne Epoxy Resin Modified by AMPS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A stable epoxy emulsion was prepared with epoxy resin (EP) as raw material, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) as modifier and benzoyl peroxide as initiator. By criterion of yield of the copolymer AMPS-EP, water-solubility, change of the acid value and intrinsic viscosity [η] along with reaction time, the copolymerization course was deduced. It is found that during the process, AMPS takes part in both the grafting copolymerization with epoxy principal chain and the ring-opening polyaddition with epoxy group. It is also discovered that the yield of AMPS-EP and water dispersing varies with reaction time. When it reaches 1.5 h,AMPS-EP can obtain good water-solubility; but the water-solubility will go bad gradually ifit exceeds 3.5 h.( )R spectrum analysis indicates that partial epoxy group partially remains and the others create sulfonic ester.

  20. Epoxy Resins Modified with Vegetable Oils

    Institute of Scientific and Technical Information of China (English)

    P.Czub

    2007-01-01

    1 Results The application of modified natural oils, nontoxic, biodegradable and renewable materials, for the modification and the synthesis of epoxy resins were presented. Firstly, the application of epoxidized vegetable oils (soybean, rapeseed, linseed and sunflower):as reactive diluents for epoxy resins was proposed and studied[1-2]. Viscosity reducing ability of epoxidized oils was tested in the compositions with Bisphenol A based low-molecular-weight epoxy resins. The rheological behaviour of the mi...

  1. 氨基树脂改性聚醚多元醇的合成及残留甲醛的去除%Synthesis of Amino-Resin Modified Polyether Polyol and Eliminating Residual Formaldehyde Method

    Institute of Scientific and Technical Information of China (English)

    张莉; 赵修文; 李博; 张利国

    2013-01-01

    以三聚氰胺、尿素、甲醛溶液、高活性聚醚多元醇为原料合成了氨基树脂改性聚醚多元醇.讨论了甲醛、三聚氰胺投料比对改性聚醚多元醇稳定性的影响,确定了减压脱除甲醛的最佳条件,对比了不同甲醛去除剂的除醛效果,并考察了改性聚醚多元醇的阻燃效果.结果表明,当甲醛与三聚氰胺投料摩尔比确定为4.5时,合成的改性聚醚多元醇稳定性最好;改性聚醚多元醇减压脱醛温度控制为100 ~120℃,时间为8h,可达到最佳脱醛效果;结合减压脱醛处理,再先后用氧化剂、甲醛捕捉剂和光触媒的分别处理可将制成高回弹聚氨酯泡沫的甲醛量降低至16 mg/kg;以改性聚醚多元醇制成的高回弹聚氨酯泡沫氧指数达到27%,最大烟密度值为4.11.%Amino resin modified polyether polyol was prepared with melamine, urea, formaldehyde solution and high active polyether polyol. The effect of formaldehyde, melamine feed ratio on the modified polyether polyol stability was dicussed. Optimal conditions for vacuum reducing the formaldehyde were determined, different formaldehyde removal agents were compared and the flame retardance of modified polyol was discussed. The results showed that, when the molar ratio of formaldehyde and melamine was determined as 4. 5, the modified polyether polyol had the best stability. When vacuum reducing formaldehyde, the temperature was controled at 100 ~ 120 ℃ and lasted for 8 h, the effect was the best. The formaldehyde amount of high resilence foam could be reduced to 16 mg/kg, the oxygen index of the foam reached 27% , maximum smoke density value was 4. 11.

  2. 乙酰苯胺修饰的后交联树脂的制备及对香兰素吸附性能%Synthesis of the Hypercrosslinked Resin Modified by Acetylaniline and Its Adsorption Performances for Vanillin

    Institute of Scientific and Technical Information of China (English)

    肖谷清; 龙立平; 王姣亮; 徐满才

    2011-01-01

    The hypercrosslinked resin modified with acetylaniline was made of chloromethylated polystyrene and acetylaniline by Friedel-Crafts reaction.Dichloroethane was used as solvent and ferric chloride was used as catalyst.The research focused on the effects of reaction conditions on the pore structures of resin and the adsorption capacity for vanillin.The results show that the optimum reaction condition is attained as follows: the reaction temperature 80 ℃,8% mass ratio of acetylaniline to chloromethylated polystyrene,25% mass ratio of ferric chloride to chloromethylated polystyrene,reaction time 10 h~12 h.The hypercrosslinked resin with good properties of the surface,pore volume,water retention capacity,the chlorine content and the adsorption capacity for vanillin was synthesized under the optimum reaction condition.The results show that the adsorption property of the hypercrosslinked resin is superior to that of XAD-4.%用二氯乙烷为溶剂,用FeCl3为催化剂,使氯球和乙酰苯胺发生Friedel-Crafts反应制得了乙酰苯胺修饰的后交联树脂,详细研究了反应条件对树脂孔结构及对香兰素吸附性能的影响。根据树脂的比表面积、孔容、持水量、氯含量和对香兰素的吸附量等孔结构和性能指标来看,乙酰苯胺修饰的后交联树脂制备的最优条件为:用二氯乙烷为溶剂,反应温度在80℃,加入氯球质量8%的乙酰苯胺,加入氯球质量25%的无水FeCl3,反应10 h~12 h。在最优条件下合成的乙酰苯胺修饰的后交联树脂对香兰素的吸附性能明显优于XAD-4树脂。

  3. Biliary intervention using SpyGlass DS cholangioscopy through a cap-attached variable-stiffness colonoscope in a patient following Billroth II gastrectomy.

    Science.gov (United States)

    Ban, Tesshin; Kawakami, Hiroshi; Kubota, Yoshimasa

    2017-09-30

    The SpyGlass DS system is currently used as a direct video cholangioscope for biliary diagnostic and therapeutic procedures. In general, the SpyGlass DS cholangioscope is passed through the working channel of a duodenoscope and inserted into a bile duct via duodenal papilla. However, the procedure has been challenging in patients with altered gastrointestinal anatomy due to the retrograde route through a potentially tortuous afferent limb. A therapeutic colonoscope with variable stiffness can offer alternative guidance for SpyGlass DS cholangioscope in patients with surgically altered gastrointestinal anatomy. Copyright © 2017 Pan-Arab Association of Gastroenterology. Published by Elsevier B.V. All rights reserved.

  4. Recycle Glass in Foam Glass Production

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    The foam glass industry turn recycle glass into heat insulating building materials. The foaming process is relative insensitive to impurities in the recycle glass. It is therefore considered to play an important role in future glass recycling. We show and discuss trends of use of recycled glasses...... in foam glass industry and the supply sources and capacity of recycle glass....

  5. Cosmos & Glass

    DEFF Research Database (Denmark)

    Beim, Anne

    1996-01-01

    The article unfolds the architectural visions of glass by Bruno Taut. It refers to inspirations by Paul Sheerbart and litterature and the Crystal Chain, also it analyses the tectonic univers that can be found in the glass pavillion for the Werkbund exposition in Cologne.......The article unfolds the architectural visions of glass by Bruno Taut. It refers to inspirations by Paul Sheerbart and litterature and the Crystal Chain, also it analyses the tectonic univers that can be found in the glass pavillion for the Werkbund exposition in Cologne....

  6. Review paper: Role of aluminum in glass-ionomer dental cements and its biological effects.

    Science.gov (United States)

    Nicholson, John W; Czarnecka, Beata

    2009-11-01

    The role of aluminum in glass-ionomers and resin-modified glass-ionomers for dentistry is reviewed. Aluminum is included in the glass component of these materials in the form of Al(2)O(3) to confer basicity on the glass and enable the glass to take part in the acid-base setting reactions. Results of studies of these reactions by FTIR and magic-angle spinning (MAS)-NMR spectroscopy are reported and the role of aluminum is discussed in detail. Aluminum has been shown to be present in the glasses in predominantly 4-coordination, as well as 5- and 6-coordination, and during setting a proportion of this is converted to 6-coordinate species within the matrix of the cement. Despite this, mature cements may contain detectable amounts of both 4- and 5-coordinate aluminum. Aluminum has been found to be leached from glass-ionomer cements, with greater amounts being released under acidic conditions. It may be associated with fluoride, with which it is known to complex strongly. Aluminum that enters the body via the gastro-intestinal tract is mainly excreted, and only about 1% ingested aluminum crosses the gut wall. Calculation shows that, if a glass-ionomer filling dissolved completely over 5 years, it would add only an extra 0.5% of the recommended maximum intake of aluminum to an adult patient. This leads to the conclusion that the release of aluminum from either type of glass-ionomer cement in the mouth poses a negligible health hazard.

  7. Glass Glimpsed

    DEFF Research Database (Denmark)

    Lock, Charles

    2015-01-01

    Glass in poetry as it reflects the viewer and as its power of reflection are both reduced and enhanced by technology.......Glass in poetry as it reflects the viewer and as its power of reflection are both reduced and enhanced by technology....

  8. Spin glasses

    CERN Document Server

    Bovier, Anton

    2007-01-01

    Spin glass theory is going through a stunning period of progress while finding exciting new applications in areas beyond theoretical physics, in particular in combinatorics and computer science. This collection of state-of-the-art review papers written by leading experts in the field covers the topic from a wide variety of angles. The topics covered are mean field spin glasses, including a pedagogical account of Talagrand's proof of the Parisi solution, short range spin glasses, emphasizing the open problem of the relevance of the mean-field theory for lattice models, and the dynamics of spin glasses, in particular the problem of ageing in mean field models. The book will serve as a concise introduction to the state of the art of spin glass theory, usefull to both graduate students and young researchers, as well as to anyone curious to know what is going on in this exciting area of mathematical physics.

  9. Effect of Caries Removal Methods on the Shear Bond Strength of Resin and Glass IonomerAdhesives to Primary Dentin

    Directory of Open Access Journals (Sweden)

    Mohammadi N

    2015-12-01

    Full Text Available Statement of Problem: There is no enough published data about the shear bond strength of resin modified glass ionomer adhesives on caries-affected primary tooth dentin excavated using minimally invasive systems. Objectives: To evaluate the shear bond strength of 2 different adhesives (one resin modified glass ionomer and one resin using two caries removal tech- niques on healthy and caries-affected primary dentin. Materials and Methods: Two caries removal methods including mechanical (handpiece and chemomechanical (Carisolv techniques and two types of ad- hesives including one resin adhesive (Clearfil SE Bond; CSEB, Kuraray and one resin-modified glass ionomer adhesive (Riva Bond LC; RBLC, SDI were used in this study. Ten extracted healthy primary teeth were used for the control group. The teeth were sectioned bucco-lingually and mesio-distally in order to obtain four specimens from each tooth. Thirty suitable specimens were selected as the “control” and randomly divided into two groups of “sound dentin” based on the type of the adhesive used. Sixty extracted caries affected teeth were used for the carious group; sectioned as mentioned above and sixty suitable specimens were selected as the “treatment”. Then the specimens were arbitrarily divided into four groups based on caries removal techniques and the type of ad- hesive used (n = 15. After bonding with either CSEB or RBLC, the specimens were restored with a resin composite by means of PVC tubes and subjected to the shear bond strength test. The data was analyzed using ANOVA and Tukey’s test. Results: The specimens in Carisolv group bonded with CSEB (11.68 ± 3.1 showed a statistically significant higher mean bond strength followed by those in handpiece group bonded with CSEB (9.4 ± 2.7, which exhibited higher mean values than those groups with RBLC (p < 0.05. Shear bond strength values for Clearfil SE Bond was not significantly higher than Riva Bond LC when used in sound

  10. In vitro microleakage of Biodentine as a dentin substitute compared to Fuji II LC in cervical lining restorations.

    Science.gov (United States)

    Raskin, Anne; Eschrich, Geoffroy; Dejou, Jacques; About, Imad

    2012-12-01

    1) To evaluate the marginal sealing efficacy of Biodentine at the cervical margins of approximal cavities placed in molars; 2) to evaluate and compare the use of Biodentine in combination with resin-based adhesives and a resin composite, compared with a resin-modified glass-ionomer cement (Fuji II LC). Sixty approximal cavities were prepared on mesial and distal surfaces of 30 extracted human third molars. The teeth were randomly assigned into 6 groups of 10 cavities each: (G1) Biodentine, (G2) Fuji II LC as a filling material, (G3) Biodentine as a base + Optibond Solo Plus + silane + Filtek Z250, (G4) as in G3 without silane, (G5) Biodentine as a base + Septobond SE + Filtek Z250, (G6) Fuji II LC as a base + Optibond Solo Plus + Filtek Z250. The materials were applied according to the manufacturers' instructions. Biodentine required no dentin or enamel surface conditioning treatment. The teeth were thermocycled 2500x (5°C to 55°C). The specimens were then sealed with a 1-mm window around the marginal interface. Samples were immersed in a 50% w/v silver nitrate solution and exposed to a photo developing solution. The teeth were embedded in resin (Sody 33) and sectioned through the restorations. The silver penetration was directly measured using a light microscope. The results were expressed as ordinal scores from 0 to 3 at cervical, interfacial, and enamel margins. The data were analyzed with the nonparametric Kruskal-Wallis, Games Howell, and Wilcoxon signed rank tests (p Biodentine or Fuji II LC)/resin composite interfaces. Statistically significant differences were observed between G5 (median score = 2.0) and the other groups (median score = 1.0) for the enamel margins. Statistically significant differences were found between enamel and dentin cervical margins in G2 (enamel median score = 1.0; dentin median score = 1.5) and G5 (enamel median score = 2.0; dentin median score = 1.0). Within the limits of this in vitro study, Biodentine as dentin substitute in

  11. Initial sliding wear kinetics of two types of glass ionomer cement: a tribological study.

    Science.gov (United States)

    Villat, Cyril; Ponthiaux, Pierre; Pradelle-Plasse, Nelly; Grosgogeat, Brigitte; Colon, Pierre

    2014-01-01

    The aim of this work was to characterize the initial wear kinetics of two different types of glass ionomer cement used in dentistry (the conventional glass ionomer cement and the resin-modified glass ionomer cement) under sliding friction after 28-day storing in distilled water or Ringer's solution. Sliding friction was applied through a pin-on-disk tribometer, in sphere-on-plane contact conditions, under 5 N normal load and 120 rotations per minute. The test lasted 7500 cycles and replicas were performed at 2500, 5000 and 7500 cycles. A profilometer was used to evaluate the wear volume. Data were analysed using Student's t-test at a significant level of 5%. There is no statistical significant difference between the results obtained for a given material with the maturation media (P > 0.05). However, for a given maturation medium, there are significant statistical differences between the data obtained for the two materials at each measurement (P glass ionomer cement weakens the tribological behaviour of this material.

  12. Minimal intervention dentistry II: part 7. Minimal intervention in cariology: the role of glass-ionomer cements in the preservation of tooth structures against caries.

    Science.gov (United States)

    Ngo, H; Opsahl-Vital, S

    2014-05-01

    Glass-ionomer cements (GICs) are essential materials in clinical practice because of their versatility, self-adhesion to enamel and dentine, and good biocompatibility. In addition, being chemically cured, with no shrinkage stress, makes them well suited for minimally invasive restorative techniques. This article looks at some of the clinical situations where the chemical adhesion and high biocompatibility of GIC are important for clinical success: excavation of deep carious lesions, fissure sealing and protection of root surfaces against caries.

  13. Pregrooving on glass disks by the sol-gel method (Part II): effects of the addition of organic polymers on the formation of glass films in the SiO2-TiO2 system

    Science.gov (United States)

    Matsuda, Atsunori; Matsuno, Yoshihiro; Kataoka, Shigeyuki; Katayama, Shinya; Tsuno, Toshio; Tohge, Noboru; Minami, Tsutomu

    1990-11-01

    The effects of the addition of polyethylene glycol(PEG) on the formation of gel-derived glass films in the Si02-TiO2 system were studied, aimed at their application to the optical memory disks. The viscosity of the as-prepared sols increased almost linearly with increasing PEG content. The increase in viscosity of the sols during the storage was retarded with decreasing molecular weight of PEG added and with increasing amount of PEG added. The viscosity increase of the sols during the storage, however, showed a similar temperature dependence, i.e. almost the same apparent activation energy was obtained, in the sols containing different amounts of PEG. These findings indicate that PEG added to the SiO2-TiO2 sols scarcely reacts with the hydrolyzed inorganic species. The hardness of the resultant PEG-containing gel films greatly decreased with increasing PEG content. The gel films containing PEG of the smaller average molecular weight showed the higher hardness and the steeper increase in hardness with increasing the heat-treatment temperature than those containing PEG of the larger average molecular weight. For a high performance in the fine patterning process and densification of the resultant patterned films, PEG of the smaller amount and the smaller molecular weight is favorable, provided the PEG-containing gel films are initially soft enough to emboss fine patterns by pressing a stamper. Incorporated PEG in the Si02-Ti02 gel films decomposed completely at temperatures over 300 °C and had a very slight influence on chemical bondings in the resultant films.

  14. Modifications in Glass Ionomer Cements: Nano-Sized Fillers and Bioactive Nanoceramics

    Directory of Open Access Journals (Sweden)

    Shariq Najeeb

    2016-07-01

    Full Text Available Glass ionomer cements (GICs are being used for a wide range of applications in dentistry. In order to overcome the poor mechanical properties of glass ionomers, several modifications have been introduced to the conventional GICs. Nanotechnology involves the use of systems, modifications or materials the size of which is in the range of 1–100 nm. Nano-modification of conventional GICs and resin modified GICs (RMGICs can be achieved by incorporation of nano-sized fillers to RMGICs, reducing the size of the glass particles, and introducing nano-sized bioceramics to the glass powder. Studies suggest that the commercially available nano-filled RMGIC does not hold any significant advantage over conventional RMGICs as far as the mechanical and bonding properties are concerned. Conversely, incorporation of nano-sized apatite crystals not only increases the mechanical properties of conventional GICs, but also can enhance fluoride release and bioactivity. By increasing the crystallinity of the set matrix, apatites can make the set cement chemically more stable, insoluble, and improve the bond strength with tooth structure. Increased fluoride release can also reduce and arrest secondary caries. However, due to a lack of long-term clinical studies, the use of nano-modified glass ionomers is still limited in daily clinical dentistry. In addition to the in vitro and in vivo studies, more randomized clinical trials are required to justify the use of these promising materials. The aim of this paper is to review the modification performed in GIC-based materials to improve their physicochemical properties.

  15. Modifications in Glass Ionomer Cements: Nano-Sized Fillers and Bioactive Nanoceramics

    Science.gov (United States)

    Najeeb, Shariq; Khurshid, Zohaib; Zafar, Muhammad Sohail; Khan, Abdul Samad; Zohaib, Sana; Martí, Juan Manuel Nuñez; Sauro, Salvatore; Matinlinna, Jukka Pekka; Rehman, Ihtesham Ur

    2016-01-01

    Glass ionomer cements (GICs) are being used for a wide range of applications in dentistry. In order to overcome the poor mechanical properties of glass ionomers, several modifications have been introduced to the conventional GICs. Nanotechnology involves the use of systems, modifications or materials the size of which is in the range of 1–100 nm. Nano-modification of conventional GICs and resin modified GICs (RMGICs) can be achieved by incorporation of nano-sized fillers to RMGICs, reducing the size of the glass particles, and introducing nano-sized bioceramics to the glass powder. Studies suggest that the commercially available nano-filled RMGIC does not hold any significant advantage over conventional RMGICs as far as the mechanical and bonding properties are concerned. Conversely, incorporation of nano-sized apatite crystals not only increases the mechanical properties of conventional GICs, but also can enhance fluoride release and bioactivity. By increasing the crystallinity of the set matrix, apatites can make the set cement chemically more stable, insoluble, and improve the bond strength with tooth structure. Increased fluoride release can also reduce and arrest secondary caries. However, due to a lack of long-term clinical studies, the use of nano-modified glass ionomers is still limited in daily clinical dentistry. In addition to the in vitro and in vivo studies, more randomized clinical trials are required to justify the use of these promising materials. The aim of this paper is to review the modification performed in GIC-based materials to improve their physicochemical properties. PMID:27428956

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

    Directory of Open Access Journals (Sweden)

    Ning Zhang

    2016-11-01

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

  17. Non-polymeric asymmetric binary glass-formers. II. Secondary relaxation studied by dielectric, (2)H NMR, and (31)P NMR spectroscopy.

    Science.gov (United States)

    Pötzschner, B; Mohamed, F; Bächer, C; Wagner, E; Lichtinger, A; Bock, D; Kreger, K; Schmidt, H-W; Rössler, E A

    2017-04-28

    We investigate the secondary (β-) relaxations of an asymmetric binary glass former consisting of a spirobichroman derivative (SBC; Tg = 356 K) as the high-Tg component and the low-Tg component tripropyl phosphate (TPP; Tg = 134 K). The main relaxations are studied in Paper I [B. Pötzschner et al., J. Chem. Phys. 146, 164503 (2017)]. A high Tg contrast of ΔTg = 222 K is put into effect in a non-polymeric system. Component-selective studies are carried out by combining results from dielectric spectroscopy (DS) for mass concentrations cTPP ≥ 60% and those from different methods of (2)H and (31)P NMR spectroscopy. In the case of NMR, the full concentration range (10% ≤ cTPP ≤ 100%) is covered. The neat components exhibit a β-relaxation (β1 (SBC) and β2 (TPP)). The latter is rediscovered by DS in the mixtures for all concentrations with unchanged time constants. NMR spectroscopy identifies the β-relaxations as being alike to those in neat glasses. A spatially highly restricted motion with angular displacement below ±10° encompassing all molecules is involved. In the low temperature range, where TPP shows the typical (31)P NMR echo spectra of the β2-process, very similar spectral features are observed for the (deuterated) SBC component by (2)H NMR, in addition to its "own" β1-process observed at high temperatures. Apparently, the small TPP molecules enslave the large SBC molecules to perform a common hindered reorientation. The temperature dependence of the spin-lattice relaxation time of both components is the same and reveals an angular displacement of the SBC molecules somewhat smaller than that of TPP, though the time constants τβ2 are the same. Furthermore, T1(T) of TPP in the temperature region of the β2-process is absolutely the same as in the mixture TPP/polystyrene investigated previously. It appears that the manifestations of the β-process introduced by one component are essentially independent of the second component. Finally, at cTPP

  18. Non-polymeric asymmetric binary glass-formers. II. Secondary relaxation studied by dielectric, 2H NMR, and 31P NMR spectroscopy

    Science.gov (United States)

    Pötzschner, B.; Mohamed, F.; Bächer, C.; Wagner, E.; Lichtinger, A.; Bock, D.; Kreger, K.; Schmidt, H.-W.; Rössler, E. A.

    2017-04-01

    We investigate the secondary (β-) relaxations of an asymmetric binary glass former consisting of a spirobichroman derivative (SBC; Tg = 356 K) as the high-Tg component and the low-Tg component tripropyl phosphate (TPP; Tg = 134 K). The main relaxations are studied in Paper I [B. Pötzschner et al., J. Chem. Phys. 146, 164503 (2017)]. A high Tg contrast of ΔTg = 222 K is put into effect in a non-polymeric system. Component-selective studies are carried out by combining results from dielectric spectroscopy (DS) for mass concentrations cTPP ≥ 60% and those from different methods of 2H and 31P NMR spectroscopy. In the case of NMR, the full concentration range (10% ≤ cTPP ≤ 100%) is covered. The neat components exhibit a β-relaxation (β1 (SBC) and β2 (TPP)). The latter is rediscovered by DS in the mixtures for all concentrations with unchanged time constants. NMR spectroscopy identifies the β-relaxations as being alike to those in neat glasses. A spatially highly restricted motion with angular displacement below ±10° encompassing all molecules is involved. In the low temperature range, where TPP shows the typical 31P NMR echo spectra of the β2-process, very similar spectral features are observed for the (deuterated) SBC component by 2H NMR, in addition to its "own" β1-process observed at high temperatures. Apparently, the small TPP molecules enslave the large SBC molecules to perform a common hindered reorientation. The temperature dependence of the spin-lattice relaxation time of both components is the same and reveals an angular displacement of the SBC molecules somewhat smaller than that of TPP, though the time constants τβ2 are the same. Furthermore, T1(T) of TPP in the temperature region of the β2-process is absolutely the same as in the mixture TPP/polystyrene investigated previously. It appears that the manifestations of the β-process introduced by one component are essentially independent of the second component. Finally, at cTPP ≤ 20% one

  19. Effects of Processing Temperature on Epoxy Resins Modified by Enzymatic Hydrolyzed Lignin%处理温度对酶解木质素改性环氧树脂性能的影响

    Institute of Scientific and Technical Information of China (English)

    孙成军; 刘彤; 赫羴姗; 邸明伟

    2015-01-01

    A corn stalk enzymatic hydrolyzed lignin was blended with epoxy resins under different processing temperatures for a certain time to modify the epoxy resin. The effect of processing temperature on the properties of the modified epoxy resin was studied via characterization of viscosity, curing process, glass transition temperature, insoluble content and mechanical properties after ageing. The results show that the viscosity of the modified epoxy increases with the increase of temperature, while the curing peak temperature of the blends of the modified epoxy resin and polyamine decreases. The glass transition temperature and the insoluble content of the cured epoxy increased with the increase of temperature. The initial mechanical strength increases as the processing temperature increases. The bending strength increases first and then decreases with the increase of ageing time. However, the impact strength decreases with the increase of ageing time.%将玉米秸秆酶解木质素与双酚A环氧树脂混合,在不同温度下预处理一定时间,用以改性环氧树脂。通过改性后树脂黏度、固化反应过程、固化后树脂的玻璃化转变温度、凝胶含量以及老化不同时间后树脂力学性能的测试,研究了处理温度对酶解木质素改性环氧树脂性能的影响。结果表明,改性后环氧树脂的黏度随处理温度的提高而增加,改性树脂/聚酰胺混合体系的固化峰值温度随处理温度的提高而降低;玻璃化转变温度和凝胶含量随处理温度的提高而增大;高温预处理的改性树脂固化物的弯曲强度均有不同程度的提高,老化后,材料的弯曲强度先升高,后降低,冲击强度则随老化时间的延长呈现持续降低的趋势。

  20. Glass Fibers: Quo Vadis?

    Directory of Open Access Journals (Sweden)

    Edith Mäder

    2017-02-01

    Full Text Available Since the early 1930s, the process of melting glass and subsequently forming fibers, in particular discontinuous fiber glass or continuous glass filaments, evolved into commercial-scale manufacturing.[...

  1. Remineralizing efficacy of silver diamine fluoride and glass ionomer type VII for their proposed use as indirect pulp capping materials - Part II (A clinical study

    Directory of Open Access Journals (Sweden)

    N Sinha

    2011-01-01

    Full Text Available Aim: To evaluate in vivo the remineralizing efficacy of silver diamine fluoride (SDF, glass ionomer Type VII (GC VII and calcium hydroxide (Dycal. Materials and Methods: 60 subjects in the age group of 18-35 years, matching the inclusion criteria and having deep carious lesions in the permanent first and second molars were selected. The teeth were aseptically opened under rubber dam and after gross caries removal, approximately 0.4mg of soft discolored dentin was removed with a sharp spoon excavator from the mesial or distal aspect of the cavity. The test material was randomly selected and applied in a thickness of 1.5-2mm and the cavity sealed with cavit. The patients were followed up at regular intervals with radiographic evaluation at 12 weeks. At 3 months the temporary restoration was removed and dentin samples were collected from the other half of the cavity which was left in the first appointment. Atomic absorption spectrophotometry, Colorimetric test using UV-vis spectrometer and potentiometric titration were used for determining calcium, phosphorous and fluoride respectively. Results: Almost equivalent rise in the percentage of calcium level was seen in GC VII and Ca(OH 2 groups, followed by SDF group. Highest percentage rise in phosphate ions was seen in GC VII group followed by SDF group and Ca(OH 2 group. Highest percentage of fluoride rise was seen in GC VII group followed by SDF group and Ca(OH 2 group. Conclusions: The results indicated that both GC VII and SDF can be potential indirect pulp capping materials.

  2. Evaluation of microleakage in posterior nanocomposite restorations with adhesive liners

    Directory of Open Access Journals (Sweden)

    B Simi

    2011-01-01

    Full Text Available Aims and Objectives : To compare the microleakage in class II nanocomposite restorations without liner, with resin-modified glass ionomer liner and flowable composite liner. Materials and Methods : Thirty-six sound premolars extracted for orthodontic reasons were selected and randomly assigned into three groups of 12 teeth each (Group I, II and III. Class II cavities of specified dimensions were prepared with margins located in the enamel. Cavities in group I were lined with resin modified glass ionomer (GC Fuji II LC-Improved, group II were lined with flowable composite (Filtex Z350 Flowable Restorative and no liner was placed for cavities in group III. All the teeth were restored with nanocomposite (Z 350 Universal Restorative. The teeth were immersed in 0.5% methylene blue dye, sectioned mesiodistally and observed under stereomicroscope. Results : Group III showed maximum leakage compared to group I and II which was statistically significant. Microleakage was lesser in group lined with resin-modified glass ionomer as compared to flowable composite group but not statistically significant. Conclusions : Placement of liner beneath nanocomposite restoration results in significant reduction in microleakage. Both resin-modified and flowable composite liners under nanocomposite restorations result in comparable reduction of microleakage.

  3. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; HRMA PR

    2009-10-08

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  4. Recycling of Glass

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Damgaard, Anders

    2011-01-01

    system; this glass though has a long lifetime before ending up in the waste. Altogether these product types add up to 82% of the production of the European glass industry (IPCC, 2001). Recycling of glass in terms of cleaning and refilling of bottles as well as the use of broken glass in the production......Glass is used for many purposes, but in the waste system glass is predominantly found in terms of beverage and food containers with a relatively short lifetime before ending up in the waste. Furthermore there is a large amount of flat glass used in building materials which also ends up in the waste...... of new glass containers is well established in the glass industry. This chapter describes briefly howglass is produced and howwaste glass is recycled in the industry. Quality requirements and use of recycled products are discussed, as are the resource and environmental issues of glass recycling....

  5. Recycling of Glass

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Damgaard, Anders

    2011-01-01

    Glass is used for many purposes, but in the waste system glass is predominantly found in terms of beverage and food containers with a relatively short lifetime before ending up in the waste. Furthermore there is a large amount of flat glass used in building materials which also ends up in the waste...... system; this glass though has a long lifetime before ending up in the waste. Altogether these product types add up to 82% of the production of the European glass industry (IPCC, 2001). Recycling of glass in terms of cleaning and refilling of bottles as well as the use of broken glass in the production...... of new glass containers is well established in the glass industry. This chapter describes briefly howglass is produced and howwaste glass is recycled in the industry. Quality requirements and use of recycled products are discussed, as are the resource and environmental issues of glass recycling....

  6. Raman scattering study of glass crystallization kinetics

    Science.gov (United States)

    Balkanski, M.; Haro, E.; Espinosa, G. P.; Phillips, J. C.

    1984-08-01

    Laser induced glass-crystalline transition is studied by light scattering. Three significant effects are observed depending on the incident laser energy density: (i) Spectral band narrowing indicating cluster enlargement constitutes a precursor effect, (ii) an intensity increase effect indicates a rapid rise of the density of clusters attaining microcrystalline size and (iii) a dynamical reversal effect indicative of glass-crystalline instability. Cluster volume and crystallization appear as separate but related threshold phenomena.

  7. Glass-silicon column

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Conrad M.

    2003-12-30

    A glass-silicon column that can operate in temperature variations between room temperature and about 450.degree. C. The glass-silicon column includes large area glass, such as a thin Corning 7740 boron-silicate glass bonded to a silicon wafer, with an electrode embedded in or mounted on glass of the column, and with a self alignment silicon post/glass hole structure. The glass/silicon components are bonded, for example be anodic bonding. In one embodiment, the column includes two outer layers of silicon each bonded to an inner layer of glass, with an electrode imbedded between the layers of glass, and with at least one self alignment hole and post arrangement. The electrode functions as a column heater, and one glass/silicon component is provided with a number of flow channels adjacent the bonded surfaces.

  8. Modified glass ionomer and orthodontic band: An interim alternative for the treatment of molar incisor hypomineralization. A case report.

    Directory of Open Access Journals (Sweden)

    Carla Orellana

    2017-03-01

    Full Text Available Introduction: Molar incisor hypomineralization (MIH is a developmental condition resulting in defects in the enamel characterized by demarcated opacities mainly affecting first permanent molars and occasionally permanent incisors in 1 of every 6 children worldwide. Affected molars have greater susceptibility to post eruptive breakdown, extensive caries and, in severe cases, are difficult to restore. When the MIH-affected molar presents severe crown destruction, it is necessary to perform an intermediate restoration to preserve the remaining dental structure in order to maintain occlusion, proper hygiene and periodontal health. The case of an 11-year-old patient with severe MIH is reported. The patient had extensive crown destruction by caries in tooth 1.6 without clinical or radiographic signs of pulp pathology. After an initial preventive intervention, enamel without dentin support and carious dentin were removed from tooth 1.6. Subsequently, crown restoration was performed with resin-modified glass ionomer, followed by the cementation of an orthodontic band. After 18 months of follow-up, the patient reported no pain or discomfort. The restoration was preserved intact, maintaining occlusal functionality, pulp and gingival health. Conclusion: The interim treatment, cementing an orthodontic band over a tooth restored with glass ionomer seems to favor retention and compressive strength, keeping the MIH-affected molar asymptomatic for at least 18 months. Further studies evaluating this treatment option in similar clinical situations are recommended.

  9. Effect of new innovative restorative carbomised glass cement on intrapulpal temperature rise: an ex-vivo study

    Directory of Open Access Journals (Sweden)

    Murat Selim BOTSALI

    2016-01-01

    Full Text Available Abstract This study aimed to evaluate the temperature changes that occurred in the pulp chamber when using GCP Glass Carbomer Fill (GCP and two different resin-modified glass-ionomer (RGI restorative materials at different dentin thicknesses. A standardized Class I occlusal cavity with 1 mm or 2 mm dentin thickness was prepared in the extracted human molar teeth. RGI and GCP fills were placed in the cavities and cured with two different light-curing units. This study included a total of 120 samples, with 20 samples in each group. The pulp microcirculation method was used for measuring the intrapulpal temperature changes. Statistical analysis was performed using the two-way ANOVA and Tukey HSD multiple comparison tests. Statistically significant differences were observed between 1 mm and 2 mm dentin thicknesses (p 0.05. The highest temperature changes were observed with 1 mm dentin thickness. While RGI materials in both dentin thicknesses did not cause temperature changes that were harmful to the pulp, GCP CarboLED LCU caused the highest intrapulpal temperature rise, and these values were borderline harmful to the dental pulp.

  10. lead glass brick

    CERN Multimedia

    When you look through the glass at a picture behind, the picture appears raised up because light is slowed down in the dense glass. It is this density (4.06 gcm-3) that makes lead glass attractive to physicists. The refractive index of the glass is 1.708 at 400nm (violet light), meaning that light travels in the glass at about 58% its normal speed. At CERN, the OPAL detector uses some 12000 blocks of glass like this to measure particle energies.

  11. Microstructuring of glasses

    CERN Document Server

    Hülsenberg, Dagmar; Bismarck, Alexander

    2008-01-01

    As microstructured glass becomes increasingly important for microsystems technology, the main application fields include micro-fluidic systems, micro-analysis systems, sensors, micro-actuators and implants. And, because glass has quite distinct properties from silicon, PMMA and metals, applications exist where only glass devices meet the requirements. The main advantages of glass derive from its amorphous nature, the precondition for its - theoretically - direction-independent geometric structurability. Microstructuring of Glasses deals with the amorphous state, various glass compositions and their properties, the interactions between glasses and the electromagnetic waves used to modify it. Also treated in detail are methods for influencing the geometrical microstructure of glasses by mechanical, chemical, thermal, optical, and electrical treatment, and the methods and equipment required to produce actual microdevices.

  12. Carbon nanotube-doped tellurite glasses

    Science.gov (United States)

    Mazali, I. O.; Chillcce, E. F.; Ferreira, O. P.; Rodriguez, E.; Jacob, G. J.; Cesar, C. L.; Barbosa, L. C.

    2008-02-01

    In the past it was observed that buck ball doped glasses showed enhanced optical nonlinearities. However, carbon nanotubes are much more stable than buck ball and should be a better choice for that purpose. Therefore we decided to investigate the possibility to produce carbon nanotubes doped tellurite glasses and measured their optical nonlinearities. Tellurite glasses already have a larger nonlinearity compared to silica, and other, glasses. We produced TeO II-ZnO tellurite family glasses doped with multi wall Carbon Nanotube (CNT). The CNTs acquired from Carbolex were vigorously mechanically mixed with the tellurite glass precursors and melted in platinum crucible around 650°C in a controlled atmosphere inside an electrical induction furnace. We used the lowest temperature possible and controlled atmosphere to avoid the CNT oxidation. The glass melt was cast in a stainless steel and thermally treated at 300°C for 5 hours to relieve internal stresses. The samples were than cutted and polished to perform the optical characterization. We measured refractive index and thermo physical properties, such as vitreous transition T g, crystallization onset T x and melting T f temperatures. Raman spectroscopy showed the possible presence of CNTs.

  13. Dynamics and thermodynamics of polymer glasses.

    Science.gov (United States)

    Cangialosi, D

    2014-04-16

    The fate of matter when decreasing the temperature at constant pressure is that of passing from gas to liquid and, subsequently, from liquid to crystal. However, a class of materials can exist in an amorphous phase below the melting temperature. On cooling such materials, a glass is formed; that is, a material with the rigidity of a solid but exhibiting no long-range order. The study of the thermodynamics and dynamics of glass-forming systems is the subject of continuous research. Within the wide variety of glass formers, an important sub-class is represented by glass forming polymers. The presence of chain connectivity and, in some cases, conformational disorder are unfavourable factors from the point of view of crystallization. Furthermore, many of them, such as amorphous thermoplastics, thermosets and rubbers, are widely employed in many applications. In this review, the peculiarities of the thermodynamics and dynamics of glass-forming polymers are discussed, with particular emphasis on those topics currently the subject of debate. In particular, the following aspects will be reviewed in the present work: (i) the connection between the pronounced slowing down of glassy dynamics on cooling towards the glass transition temperature (Tg) and the thermodynamics; and, (ii) the fate of the dynamics and thermodynamics below Tg. Both aspects are reviewed in light of the possible presence of a singularity at a finite temperature with diverging relaxation time and zero configurational entropy. In this context, the specificity of glass-forming polymers is emphasized.

  14. Infrared Transparent Selenide Glasses.

    Science.gov (United States)

    1997-03-14

    crystalline halides, silica and fluoride glasses, and chalcogenide glasses. Crystalline halides undergo plastic deformation and are hygroscopic...mainly for applications operating at wavelengths less than 3 microns. Silicate and fluoride glasses have been developed as optical fiber amplifiers...activity. Preferred rare earths includes praseodymium, neodymium, erbium, cerium , dysprosium, holmium, thulium, terbium, ytterbium or mixtures of

  15. Fluoride glass fiber optics

    CERN Document Server

    Aggarwal, Ishwar D

    1991-01-01

    Fluoride Glass Fiber Optics reviews the fundamental aspects of fluoride glasses. This book is divided into nine chapters. Chapter 1 discusses the wide range of fluoride glasses with an emphasis on fluorozirconate-based compositions. The structure of simple fluoride systems, such as BaF2 binary glass is elaborated in Chapter 2. The third chapter covers the intrinsic transparency of fluoride glasses from the UV to the IR, with particular emphasis on the multiphonon edge and electronic edge. The next three chapters are devoted to ultra-low loss optical fibers, reviewing methods for purifying and

  16. Multiple Glass Ceilings

    OpenAIRE

    Russo, Giovanni; Hassink, Wolter

    2011-01-01

    Both vertical (between job levels) and horizontal (within job levels) mobility can be sources of wage growth. We find that the glass ceiling operates at both margins. The unexplained part of the wage gap grows across job levels (glass ceiling at the vertical margin) and across the deciles of the intra-job-level wage distribution (glass ceiling at the horizontal margin). This implies that women face many glass ceilings, one for each job level above the second, and that the glass ceiling is a p...

  17. GLASS COMPOSITION AND SOLUTION SPECIATION EFFECTS ON STAGE III DISSOLUTION

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-10-03

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

  18. Poly(vinyl chloride) composite emulsion resins modified by polyurethane

    Institute of Scientific and Technical Information of China (English)

    Xiaolei ZHANG; Mingwang PAN; Shengnan XING; Jingsheng LI

    2008-01-01

    An ionomer-type of polyurethane (PU) emul-sion was prepared from toluene diisocyanate (TDI), polypropylene glycol (PPG) and dimethylol propionic acid (DMPA) following a self-emulsification process. The modified poly(vinyl chloride) (PVC) emulsion resin was obtained by in situ emulsion copolymerization using the PU as seeds in an autoclave. The effects of PU molecular weight on the mechanical properties and thermal stability of the PU/PVC materials were investigated. The composite latex particles and composite materials were determined and characterized using a laser particle size analyzer, transmission electron microscopy or scanning electron microscopy. The study results showed that the PU/PVC hybrid emulsion particles possess a core/shell structure. When the general mechanical properties of the composite materials increase, the thermal stabilities decrease a little. The tough fractures on the surface of the PU/PVC composite sample following impact are quite obvious.

  19. Glass and glass-ceramic photonic systems

    Science.gov (United States)

    Zur, Lidia; Thi Ngoc Tran, Lam; Meneghetti, Marcello; Varas, Stefano; Armellini, Cristina; Ristic, Davor; Chiasera, Alessandro; Scotognella, Francesco; Pelli, Stefano; Nunzi Conti, Gualtiero; Boulard, Brigitte; Zonta, Daniele; Dorosz, Dominik; Lukowiak, Anna; Righini, Giancarlo C.; Ramponi, Roberta; Ferrari, Maurizio

    2017-02-01

    The development of optically confined structure is a major topic in both basic and applied physics not solely ICT oriented but also concerning lighting, laser, sensing, energy, environment, biological and medical sciences, and quantum optics. Glasses and glass-ceramics activated by rare earth ions are the bricks of such structures. Glass-ceramics are nanocomposite systems that exhibit specific morphologic, structural and spectroscopic properties allowing developing new physical concepts, for instance the mechanism related to the transparency, as well as novel photonic devices based on the enhancement of the luminescence. The dependence of the final product on the specific parent glass and on the fabrication protocol still remain an important task of the research in material science. Looking to application, the enhanced spectroscopic properties typical of glass ceramic in respect to those of the amorphous structures constitute an important point for the development of integrated optics devices, including optical amplifiers, monolithic waveguide laser, novel sensors, coating of spherical microresonators, and up and down converters. This paper presents some results obtained by our consortium regarding glass-based photonics systems. We will comment the energy transfer mechanism in transparent glass ceramics taking as examples the up and down conversion systems and the role of SnO2 nanocrystals as sensitizers. Coating of spherical resonators by glass ceramics, 1D-Photonic Crystals for luminescence enhancement, laser action and disordered 1-D photonic structures will be also discussed. Finally, RF-Sputtered rare earth doped P2O5- SiO2-Al2O3-Na2O-Er2O3 planar waveguides, will be presented.

  20. Comparative Evaluation of Wear Rate of Different Riva Glass Ionomers

    Directory of Open Access Journals (Sweden)

    Vahid Yaghoubi

    2016-12-01

    Full Text Available Introduction: wear is one of the most important factors that cause loss of restorations. The aim of this study was to evaluate the wear rate in light-cured glass ionomers SDI. Materials and Methods: 20 samples consisted of light-cured Ionomer Glass Riva and Riva HV and Fuji II and composit Z250 to 2mm and length and width 10mm in Copper generator were prepared (n = 5 and were put in a wear device. Samples in wear cycles, in the course of 5000, 10000, 20000, 40000, 80000, 120000 respectively cycles via cobalt chrome cylindrical abrasive was under wear. Digital scale with 0.1 mg precision was used for gravimetric. Data using One Way Anova and Post hoc Tukey test and Spss software was analyzed. Results: The weight loss was as follows: Glass Ionomer light cure Riva ˂Glass Ionomer light cure Riva HV ˂Glass Ionomer light cure Fuji II ˂composite Z250. The other three groups were statistically significant weight loss between the composite Z250 and but the difference in weight loss between the groups and Glass Ionomer light cure Riva, Glass Ionomer light cure Riva HV, Glass Ionomer light cure Fuji II was found after 120,000 cycles. Conclusion: The results of this study showed the wear of glass ionomers Capsule Riva is similar Fuji II LC but the wear of glass inomers is much more than composite Z250 which seems ready to take in areas not exposed to occlusal stress.

  1. Liquid Glass: A Facile Soft Replication Method for Structuring Glass.

    Science.gov (United States)

    Kotz, Frederik; Plewa, Klaus; Bauer, Werner; Schneider, Norbert; Keller, Nico; Nargang, Tobias; Helmer, Dorothea; Sachsenheimer, Kai; Schäfer, Michael; Worgull, Matthias; Greiner, Christian; Richter, Christiane; Rapp, Bastian E

    2016-06-01

    Liquid glass is a photocurable amorphous silica nanocomposite that can be structured using soft replication molds and turned into glass via thermal debinding and sintering. Simple polymer bonding techniques allow the fabrication of complex microsystems in glass like microfluidic chips. Liquid glass is a step toward prototyping of glass microstructures at low cost without requiring cleanroom facilities or hazardous chemicals.

  2. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    The use of glass as a load carrying material in structural elements is rarely seen even though glass is a popular material for many architects. This is owed to the unreliable and low tensile strength, which is due to surface flaws and high brittleness of the material. These properties lead...... to breakage without any warning or ductility, which can be catastrophic if no precautions are taken. One aspect of this issue is treated here by looking at the possibility of mechanically reinforcing glass beams in order to obtain ductile failure for such a structural component. A mechanically reinforced...... laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...

  3. Radiation effects in glasses

    Energy Technology Data Exchange (ETDEWEB)

    Ehrt, D.; Vogel, W. (Otto-Schott-Inst., Chemische Fakultaet, Friedrich-Schiller-Univ., Jena (Germany))

    1992-03-01

    Glass was produced by man about 4000 years ago. The scientific exploration of glass is very young and closely connected with Jena. Fraunhofer, Goethe, Dobereiner, Abbe, Zeiss and Schott are famous names on this field. Both crystals and glasses are solids. However, there are fundamental differences in their properties and behavior. Glass is a thermodynamically unstable state and has a defect structure compared to the crystal. Glass and its properties are subject to a variety of changes under the influence of high energy radiation. In general, effects extend from the reduction of specific ions to the collapse of the entire network. Ultraviolet and X-ray radiation effects on UV-transmitting glasses will be discussed. (orig.).

  4. Homogeneity of Inorganic Glasses

    DEFF Research Database (Denmark)

    Jensen, Martin; Zhang, L.; Keding, Ralf;

    2011-01-01

    Homogeneity of glasses is a key factor determining their physical and chemical properties and overall quality. However, quantification of the homogeneity of a variety of glasses is still a challenge for glass scientists and technologists. Here, we show a simple approach by which the homogeneity...... of different glass products can be quantified and ranked. This approach is based on determination of both the optical intensity and dimension of the striations in glasses. These two characteristic values areobtained using the image processing method established recently. The logarithmic ratio between...... the dimension and the intensity is used to quantify and rank the homogeneity of glass products. Compared with the refractive index method, the image processing method has a wider detection range and a lower statistical uncertainty....

  5. Homogeneity of Inorganic Glasses

    DEFF Research Database (Denmark)

    Jensen, Martin; Zhang, L.; Keding, Ralf

    2011-01-01

    Homogeneity of glasses is a key factor determining their physical and chemical properties and overall quality. However, quantification of the homogeneity of a variety of glasses is still a challenge for glass scientists and technologists. Here, we show a simple approach by which the homogeneity...... of different glass products can be quantified and ranked. This approach is based on determination of both the optical intensity and dimension of the striations in glasses. These two characteristic values areobtained using the image processing method established recently. The logarithmic ratio between...... the dimension and the intensity is used to quantify and rank the homogeneity of glass products. Compared with the refractive index method, the image processing method has a wider detection range and a lower statistical uncertainty....

  6. Raman Spectra of Glasses

    Science.gov (United States)

    1986-11-30

    17), Raman spectra, plus a , . theoretical treatment of the data, f complex fluorozirconate 14 I anions in ZBLAN glasses and melts (16), and...based ZBLAN glasses ) 17. ICORS (International Conference on Raman Spectroscopy) Proceedings, London, England. Conferencf 5-9 Sep 88. (Molten silica...RESEARCH FINAL REPORT DTIC CONTRACT N00014-81-K-0501 &JELECTE 1 MAY 81 -- 30 NOV 86 EJJAN041989 V "RAMAN SPECTRA OF GLASSES " 0 During the five years of the

  7. Diamond turning of glass

    Energy Technology Data Exchange (ETDEWEB)

    Blackley, W.S.; Scattergood, R.O.

    1988-12-01

    A new research initiative will be undertaken to investigate the critical cutting depth concepts for single point diamond turning of brittle, amorphous materials. Inorganic glasses and a brittle, thermoset polymer (organic glass) are the principal candidate materials. Interrupted cutting tests similar to those done in earlier research are Ge and Si crystals will be made to obtain critical depth values as a function of machining parameters. The results will provide systematic data with which to assess machining performance on glasses and amorphous materials

  8. Metal Halide Optical Glasses.

    Science.gov (United States)

    1988-01-01

    while some of the multi- component "modified" glasses (e.g., ZBLAN ) could easily be cast into pieces several mm thick. 23 The difference between the...energy. 7-1 0 Typical plots pf 24 of log Iqi versus ]/Tf for ZB-I, ZBL, ZBLA, ZBLAN and ZBLALi glasses are presented in Fig. 3. These plots are linear... ZBLAN glasses are more resistant to devitrification than the corresponding ZBLLi or ZBLN glasses , although this does not appear to be manifested in

  9. 不同类型玻璃离子水门汀的氟释放行为与溶解性%Comparison of fluoride release and solubility for different glass ionomer cements

    Institute of Scientific and Technical Information of China (English)

    刘莉霞; 陈琳

    2014-01-01

    背景:改性玻璃离子水门汀提高了玻璃离子水门汀的机械性能、耐磨性和美观性,被逐渐应用于口腔临床的诸多方面,但对改性玻璃离子水门汀的氟释放行为和溶解特性尚不明确。目的:考察FujiⅡ传统型玻璃离子水门汀、Fuji Plus羟基磷灰石改性型玻璃离子水门汀、FujiⅨ金属增强型玻璃离子水门汀及FujiⅡLC光固化树脂改性型玻璃离子水门汀在人工唾液中的氟释放行为与溶解特性。方法:将4种玻璃离子水门汀试样浸没在人工唾液中,采用氟离子选择性电极测定试样浸泡0-28 d的氟释放量;利用分析天平测定试样浸泡3,7,14,28 d的质量,以算溶解率,采用SPSS软件和Origin软件分别进行氟释放量统计学分析和非线性拟合回归分析。结果与结论:各玻璃离子水门汀均在第1天达到最高的氟释放量,在随后几天迅速下降,之后保持稳定,其中FujiⅡLC光固化树脂改性型玻璃离子水门汀的氟释放单日量与累积量,以及溶解率显著高于其他3种玻璃离子水门汀(P <0.01)。方程Y=a+b*t0.5+c*t可较好模拟氟释放累积量变化过程,氟释放累积量与溶解率近似呈正比例关系。FujiⅡLC光固化树脂改性型玻璃离子水门汀达到最高的氟释放累积量与溶解率比值。%BACKGROUND:Modified glass ionomer cements improve the mechanical properties, abrasion resistance and beauty of traditional glass ionomer cements, and therefore they have been gradualy adopted in many fields of oral clinical application. However, it is not clear that the fluoride release behavior and soluble characteristics. OBJECTIVE:To investigate the fluoride release behavior and soluble characteristics of four glass ionomer cements in artificial saliva: Fuji II tranditional type, Fuji Plus hydroxyapatite modified type, Fuji IX metal modified type, and Fuji II LC light-curing resin modified type. METHODS: For each glass

  10. Memo, "Incorporation of HLW Glass Shell V2.0 into the Flowsheets," to ED Lee, CCN: 184905, October 20, 2009

    Energy Technology Data Exchange (ETDEWEB)

    Gimpel, Rodney F.; Kruger, Albert A.

    2013-12-18

    Efforts are being made to increase the efficiency and decrease the cost of vitrifying radioactive waste stored in tanks at the U.S. Department of Energy Hanford Site. The compositions of acceptable and processable high-level waste (HL W) glasses need to be optimized to minimize the waste-form volume and, hence, to reduce cost. A database of glass properties of waste glass and associated simulated waste glasses was collected and documented in PNNL 18501, Glass Property Data and Models for Estimating High-Level Waste Glass Volume and glass property models were curve-fitted to the glass compositions. A routine was developed that estimates HL W glass volumes using the following glass property models: II Nepheline, II One-Percent Crystal Temperature (T1%), II Viscosity (11) II Product Consistency Tests (PCT) for boron, sodium, and lithium, and II Liquidus Temperature (TL). The routine, commonly called the HL W Glass Shell, is presented in this document. In addition to the use of the glass property models, glass composition constraints and rules, as recommend in PNNL 18501 and in other documents (as referenced in this report) were incorporated. This new version of the HL W Glass Shell should generally estimate higher waste loading in the HL W glass than previous versions.

  11. Lanthanoides in Glass and Glass Ceramics

    Science.gov (United States)

    Meinhardt, Jürgen; Kilo, Martin; Somorowsky, Ferdinand; Hopp, Werner

    2017-03-01

    Many types of glass contain lanthanoides; among them, special glass for optical applications is the one with the highest content of lanthanoides. The precise determination of the lanthanoides' concentration is performed by inductively coupled plasma-optical emission spectrometry (ICP-OES). However, up to now, there are no established standard processes guaranteeing a uniform approach to the lanthanoide analysis. The knowledge of the lanthanoides' concentrations is necessary on the microscale in some cases, especially if a suitable separation and recycling procedure is to be applied. Here, the analysis is performed by energy-dispersive X-ray (EDX) or wavelength-dispersive X-ray (WDX) analytics in the scanning electron microscope.

  12. In vitro evaluation of marginal microleakage of class II bonded amalgam restorations using a dentin adhesive and a glass ionomer cement Avaliação in vitro da microinfiltração marginal em restaurações de amálgama tipo classe II usando adesivo dentinário e cimento de ionômero de vidro

    Directory of Open Access Journals (Sweden)

    Edmêr Silvestre PEREIRA JÚNIOR

    1999-04-01

    Full Text Available The purpose of this study was to evaluate in vitro the effectiveness of the dentin bonding system All Bond 2 associated with Resinomer (Bisco, and of Vitrebond (3M glass ionomer cement fresh-mixed, both used in the bonded amalgam technique, to prevent short-term microleakage in class II cavities restored with Dispersalloy (Dentsply, an admixed alloy. The control group utilized the Copalite (Cooley & Cooley varnish. Forty five sound human extracted premolars were used. Class II cavity preparations were made on the mesial and distal surfaces of non-carious teeth, with the gingival margins wall established 1mm under the cementum enamel junction. The specimens were divided randomly into three groups with thirty cavities in each group. The teeth were stored in distilled water for 24 hours and were thermocyled through 500 cycles in distilled water between 5°C and 55°C with a dwell time of 15 seconds. The apices and roots of the teeth were sealed. They were placed in a 37°C bath of 0.5% basic fuchsin dye for 24 hours. The teeth were washed in tap water for 24 hours and cut. The microleakage scores per restoration were averaged and three values of various test groups were subjected to the Kruskal-Wallis and Dunn test at a significance level of p O objetivo deste estudo foi avaliar in vitro a efetividade na prevenção da microinfiltração do sistema adesivo All Bond 2 associado ao Resinomer (Bisco, e do cimento de ionômero de vidro Vitrebond (3M, sem polimerização, em amálgama adesivo classe II, restauradas com Dispersalloy (Dentsply. No grupo controle utilizou-se o verniz cavitário Copalite (Cooley & Cooley. Para tanto, 45 pré-molares humanos íntegros e extraídos, com finalidade ortodôntica, receberam cavidades classe II, sendo uma na face mesial e outra na face distal de cada dente, com a parede cervical localizada a 1mm além da junção cemento-esmalte, sendo 30 cavidades em cada grupo. Após as restaurações os dentes foram estocados

  13. Electric glass capturing markets

    Energy Technology Data Exchange (ETDEWEB)

    Wikman, K.; Wikstroem, T.

    1996-11-01

    Electric glass has found its place on the construction market. In public buildings, electrically heatable windows are becoming the leading option for large glass walls. Studies on detached houses, both new and renovated, show that floor heating combined with electrically heatable windowpanes is the best choice with respect to resident`s comfort. (orig.)

  14. lead glass brick

    CERN Multimedia

    As well as accelerators to boost particles up to high energy, physicists need detectors to see what happens when those particles collide. This lead glass block is part of a CERN detector called OPAL. OPAL uses some 12 000 blocks of glass like this to measure particle energies.

  15. Glasses for photonic applications

    NARCIS (Netherlands)

    Richardson, K.; Krol, D.M.; Hirao, K.

    2010-01-01

    Recent advances in the application of glassy materials in planar and fiber-based photonic structures have led to novel devices and components that go beyond the original thinking of the use of glass in the 1960s, when glass fibers were developed for low-loss, optical communication applications. Expl

  16. Getting Started with Glass

    Science.gov (United States)

    White, Heather

    2007-01-01

    The metamorphosis of glass when heated is a magical process to students, yet teachers are often reluctant to try it in class. The biggest challenge in working with glass in the classroom is to simplify procedures just enough to ensure student success while maintaining strict safety practices so no students are injured. Project concepts and safety…

  17. Glass Sword of Damocles

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A string of accidents draws attention to the safety of the gleaming glass-walled skyscrapers, now common in China’s major cities On July 8, as 19-year-old Zhu Yiyi was walking past a 23-story building in Hangzhou, east China’s Zhejiang Province, shards of glass falling

  18. Electric glass capturing markets

    Energy Technology Data Exchange (ETDEWEB)

    Wikman, K.; Wikstroem, T.

    1996-11-01

    Electric glass has found its place on the construction market. In public buildings, electrically heatable windows are becoming the leading option for large glass walls. Studies on detached houses, both new and renovated, show that floor heating combined with electrically heatable windowpanes is the best choice with respect to resident`s comfort. (orig.)

  19. Defense HLW Glass Degradation Model

    Energy Technology Data Exchange (ETDEWEB)

    D. Strachan

    2004-10-20

    The purpose of this report is to document the development of a model for calculating the release rate for radionuclides and other key elements from high-level radioactive waste (HLW) glasses under exposure conditions relevant to the performance of the repository. Several glass compositions are planned for the repository, some of which have yet to be identified (i.e., glasses from Hanford and Idaho National Engineering and Environmental Laboratory). The mechanism for glass dissolution is the same for these glasses and the glasses yet to be developed for the disposal of DOE wastes. All of these glasses will be of a quality consistent with the glasses used to develop this report.

  20. Thermal Conductivity of Foam Glass

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    Due to the increased focus on energy savings and waste recycling foam glass materials have gained increased attention. The production process of foam glass is a potential low-cost recycle option for challenging waste, e.g. CRT glass and industrial waste (fly ash and slags). Foam glass is used...... as thermal insulating material in building and chemical industry. The large volume of gas (porosity 90 – 95%) is the main reason of the low thermal conductivity of the foam glass. If gases with lower thermal conductivity compared to air are entrapped in the glass melt, the derived foam glass will contain...... only closed pores and its overall thermal conductivity will be much lower than that of the foam glass with open pores. In this work we have prepared foam glass using different types of recycled glasses and different kinds of foaming agents. This enabled the formation of foam glasses having gas cells...

  1. Property Data for Simulated Americium/Curium Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Riley, B.J.; Smith, D.E.; Peeler, D.K.; Reamer, I.A.; Vienna, J.D.; Schweiger, M.J.

    1999-10-20

    The authors studied the properties of mixed lanthanide-alumino-borosilicate glasses. Fifty-five glasses were designed to augment a previous, Phase I, study by systematically varying the composition of Ln{sub 2}O{sub 3} and the concentrations of Ln{sub 2}O{sub 3}, SiO{sub 2}, B{sub 2}O{sub 3}, Al{sub 2}O{sub 3}, and SrO in glass. These glasses were designed and fabricated at the Savannah River Technology Center and tested at the Pacific Northwest National Laboratory. The properties measured include the high-temperature viscosity ({eta}) as a function of temperature (T) and the liquidus temperature (T{sub L}) of Phase II test glasses.

  2. Bioactive glasses and glass-ceramics

    Directory of Open Access Journals (Sweden)

    de Aza, P. N.

    2007-04-01

    Full Text Available Since the late 1960´s, a great interest in the use of bioceramic materials for biomedical applications has been developed. In a previous paper, the authors reviewed crystalline bioceramic materials “sensus stricto”, it is to say, those ceramic materials, constituted for non-metallic inorganic compounds, crystallines and consolidates by thermal treatment of powders at high temperature. In the present review, the authors deal with those called bioactive glasses and glassceramics. Although all of them are also obtained by thermal treatment at high temperature, the first are amorphous and the second are obtained by devitrification of a glass, although the vitreous phase normally prevails on the crystalline phases. After an introduction to the concept of bioactive materials, a short historical review of the bioactive glasses development is made. Its preparation, reactivity in physiological media, mechanism of bonding to living tissues and mechanical strength of the bone-implant interface is also reported. Next, the concept of glass-ceramic and the way of its preparation are exposed. The composition, physicochemical properties and biological behaviour of the principal types of bioactive glasses and glass-ceramic materials: Bioglass®, Ceravital®, Cerabone®, Ilmaplant® and Bioverit® are also reviewed. Finally, a short review on the bioactive-glass coatings and bioactive-composites and most common uses of bioactive-glasses and glass-ceramics are carried out too.

    Desde finales de los años sesenta, se ha despertado un gran interés por el uso de los materiales biocerámicos para aplicaciones biomédicas. En un trabajo previo, los autores hicieron una revisión de los denominados materiales biocerámicos cristalinos en sentido estricto, es decir, de aquellos materiales, constituidos por compuestos inorgánicos no metálicos, cristalinos y consolidados mediante tratamientos térmicos a altas temperaturas. En el presente trabajo, los autores

  3. cobalt (ii), nickel (ii)

    African Journals Online (AJOL)

    DR. AMINU

    ABSTRACT. The manganese (II), cobalt (II), nickel (II) and copper (II) complexes of N, N' – ... temperature and coordinated water were determined ... indicating fairly stable complex compounds (Table 1). The complex compounds are insoluble [Table 2] in water and common organic solvents, but are readily soluble in ...

  4. High-level waste borosilicate glass: A compendium of corrosion characteristics. Volume 3

    Energy Technology Data Exchange (ETDEWEB)

    Cunnane, J.C. [comp.; Bates, J.K.; Bradley, C.R. [Argonne National Lab., IL (United States)] [and others

    1994-03-01

    The objective of this document is to summarize scientific information pertinent to evaluating the extent to which high-level waste borosilicate glass corrosion and the associated radionuclide release processes are understood for the range of environmental conditions to which waste glass may be exposed in service. Alteration processes occurring within the bulk of the glass (e.g., devitrification and radiation-induced changes) are discussed insofar as they affect glass corrosion. Volume III contains a bibliography of glass corrosion studies, including studies that are not cited in Volumes I and II.

  5. Shattering the Glass Ceiling

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ "Shattering the Glass Ceiling: the Myths, Opportunities and Chal lenges of Women in Corporate China" was the theme of CEIBS'first Women in Management Forum held on December l 1 on the school's main campus in Shanghai.

  6. Glass Stronger than Steel

    Science.gov (United States)

    Yarris, Lynn

    2011-03-28

    A new type of damage-tolerant metallic glass, demonstrating a strength and toughness beyond that of steel or any other known material, has been developed and tested by a collaboration of researchers from Berkeley Lab and Caltech.

  7. Glass for Solar Concentrators

    Science.gov (United States)

    Bouquet, F. L.

    1984-01-01

    Report identifies four commercially available glasses as promising reflectors for solar concentrators. Have properties of high reflectance (80 to 96 percent), lower cost than first-surface silver metalization, and resistance to environmental forces.

  8. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    to breakage without any warning or ductility, which can be catastrophic if no precautions are taken. One aspect of this issue is treated here by looking at the possibility of mechanically reinforcing glass beams in order to obtain ductile failure for such a structural component. A mechanically reinforced...... the mechanical behavior of the beam is explained. Finally, some design criterions for reinforced glass beams are discussed....

  9. Baseline LAW Glass Formulation Testing

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Albert A. [USDOE Office of River Protection, Richland, WA (United States); Mooers, Cavin [The Catholic University of America, Washington, DC (United States). Vitreous State Lab.; Bazemore, Gina [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Pegg, Ian L. [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Hight, Kenneth [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Lai, Shan Tao [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Buechele, Andrew [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Rielley, Elizabeth [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Gan, Hao [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Muller, Isabelle S. [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Cecil, Richard [The Catholic University of America, Washington, DC (United States). Vitreous State Lab

    2013-06-13

    The major objective of the baseline glass formulation work was to develop and select glass formulations that are compliant with contractual and processing requirements for each of the LAW waste streams. Other objectives of the work included preparation and characterization of glasses with respect to the properties of interest, optimization of sulfate loading in the glasses, evaluation of ability to achieve waste loading limits, testing to demonstrate compatibility of glass melts with melter materials of construction, development of glass formulations to support ILAW qualification activities, and identification of glass formulation issues with respect to contract specifications and processing requirements.

  10. Effect of acid etching of glass ionomer cement surface on the microleakage of sandwich restorations.

    Science.gov (United States)

    Bona, Alvaro Della; Pinzetta, Caroline; Rosa, Vinícius

    2007-06-01

    The purposes of this study were to evaluate the sealing ability of different glass ionomer cements (GICs) used for sandwich restorations and to assess the effect of acid etching of GIC on microleakage at GIC-resin composite interface. Forty cavities were prepared on the proximal surfaces of 20 permanent human premolars (2 cavities per tooth), assigned to 4 groups (n=10) and restored as follows: Group CIE - conventional GIC (CI) was applied onto the axial and cervical cavity walls, allowed setting for 5 min and acid etched (E) along the cavity margins with 35% phosphoric acid for 15 s, washed for 30 s and water was blotted; the adhesive system was applied and light cured for 10 s, completing the restoration with composite resin light cured for 40 s; Group CIN - same as Group CIE, except for acid etching of the CI surface; Group RME - same as CIE, but using a resin modified GIC (RMGIC); Group RMN - same as Group RME, except for acid etching of the RMGIC surface. Specimens were soaked in 1% methylene blue dye solution at 24 degrees C for 24 h, rinsed under running water for 1 h, bisected longitudinally and dye penetration was measured following the ISO/TS 11405-2003 standard. Results were statistically analyzed by Kruskal-Wallis and chi-square tests (a=0.05). Dye penetration scores were as follow: CIE - 2.5; CIN - 2.5; RME - 0.9; and RMN - 0.6. The results suggest that phosphoric acid etching of GIC prior to the placement of composite resin does not improve the sealing ability of sandwich restorations. The RMGIC was more effective in preventing dye penetration at the GIC-resin composite-dentin interfaces than CI.

  11. Effect of acid etching of glass ionomer cement surface on the microleakage of sandwich restorations

    Directory of Open Access Journals (Sweden)

    Álvaro Della Bona

    2007-06-01

    Full Text Available The purposes of this study were to evaluate the sealing ability of different glass ionomer cements (GICs used for sandwich restorations and to assess the effect of acid etching of GIC on microleakage at GIC-resin composite interface. Forty cavities were prepared on the proximal surfaces of 20 permanent human premolars (2 cavities per tooth, assigned to 4 groups (n=10 and restored as follows: Group CIE - conventional GIC (CI was applied onto the axial and cervical cavity walls, allowed setting for 5 min and acid etched (E along the cavity margins with 35% phosphoric acid for 15 s, washed for 30 s and water was blotted; the adhesive system was applied and light cured for 10 s, completing the restoration with composite resin light cured for 40 s; Group CIN - same as Group CIE, except for acid etching of the CI surface; Group RME - same as CIE, but using a resin modified GIC (RMGIC; Group RMN - same as Group RME, except for acid etching of the RMGIC surface. Specimens were soaked in 1% methylene blue dye solution at 24ºC for 24 h, rinsed under running water for 1 h, bisected longitudinally and dye penetration was measured following the ISO/TS 11405-2003 standard. Results were statistically analyzed by Kruskal-Wallis and chi-square tests (a=0.05. Dye penetration scores were as follow: CIE - 2.5; CIN - 2.5; RME - 0.9; and RMN - 0.6. The results suggest that phosphoric acid etching of GIC prior to the placement of composite resin does not improve the sealing ability of sandwich restorations. The RMGIC was more effective in preventing dye penetration at the GIC-resin composite-dentin interfaces than CI.

  12. Wastes based glasses and glass-ceramics

    Directory of Open Access Journals (Sweden)

    Barbieri, L.

    2001-12-01

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

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

  13. Strength characteristics and marginal sealing ability of chlorhexidine-modified glass ionomer cement: An in vitro study

    OpenAIRE

    Ahluwalia, P.; Chopra, S; Thomas, A. M.

    2012-01-01

    Background: This study was done to compare and evaluate the compressive strength, diametral tensile strength, and microleakage of glass ionomer cement and chlorhexidine-modified glass ionomer cement. The glass ionomer cements used in the study were Fuji IX for group I and chlorhexidine-modified glass ionomer cement for group II. Materials and Methods: The strength characteristics (compressive and diametral tensile strengths) and microleakage of both the groups were evaluated after 24 h. Stude...

  14. Evaluation of adhesive and compressive strength of glass ionomer cements.

    Science.gov (United States)

    Ramashanker; Singh, Raghuwar D; Chand, Pooran; Jurel, Sunit Km; Tripathi, Shuchi

    2011-12-01

    The aim of the study was to assess, compare and evaluate the adhesive strength and compressive strength of different brands of glass ionomer cements to a ceramometal alloy. (A) Glass ionomer cements: GC Fuji II (GC Corporation, Tokyo), Chem Flex (Dentsply DeTrey, Germany), Glass ionomer FX (Shofu-11, Japan), MR dental (MR dental suppliers Pvt Ltd, England). (B) Ceramometal alloy (Ni-Cr: Wiron 99; Bego, Bremen, Germany). (C) Cold cure acrylic resin. (E) Temperature cum humidity control chamber. (F) Instron Universal Testing Machine. Four different types of Glass ionomer cements were used in the study. From each type of the Glass ionomer cements, 15 specimens for each were made to evaluate the compressive strength and adhesive strength, respectively. The 15 specimens were further divided into three subgroups of five specimens. For compressive strength, specimens were tested at 2, 4 and 12 h by using Instron Universal Testing Machine. To evaluate the adhesive strength, specimens were surface treated with diamond bur, silicone carbide bur and sandblasting and tested under Instron Universal Testing Machine. It was concluded from the study that the compressive strength as well as the adhesive bond strength of MR dental glass ionomer cement with a ceramometal alloy was found to be maximum compare to other glass ionomer cements. Sandblasting surface treatment of ceramometal alloy was found to be comparatively more effective for adhesive bond strength between alloy and glass ionomer cement.

  15. Glass microsphere lubrication

    Science.gov (United States)

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

    1991-01-01

    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the

  16. Optimized Synthesis of Foam Glass from Recycled CRT Panel Glass

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    Most of the panel glass from cathode ray tubes (CRTs) is landfilled today. Instead of landfilling, the panel glass can be turned into new environment-friendly foam glass. Low density foam glass is an effective heat insulating material and can be produced just by using recycle glass and foaming...... additives. In this work we recycle the CRT panel glass to synthesize the foam glass as a crucial component of building and insulating materials. The synthesis conditions such as foaming temperature, duration, glass particle size, type and concentrations of foaming agents, and so on are optimized...... by performing systematic experiments. In particular, the concentration of foaming agents is an important parameter that influences the size of bubbles and the distribution of bubbles throughout the sample. The foam glasses are characterised regarding density and open/closed porosity. Differential scanning...

  17. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D; Bradley Pickenheim, B

    2008-11-24

    DWPF is considering replacing irregularly shaped glass frit with spherical glass beads in the Slurry Mix Evaporator (SME) process to decrease the yield stress of the melter feed (a non-Newtonian Bingham Plastic). Pilot-scale testing was conducted on spherical glass beads and glass frit to determine how well the glass beads would transfer when compared to the glass frit. Process Engineering Development designed and constructed the test apparatus to aid in the understanding and impacts that spherical glass beads may have on the existing DWPF Frit Transfer System. Testing was conducted to determine if the lines would plug with the glass beads and the glass frit slurry and what is required to unplug the lines. The flow loop consisted of vertical and horizontal runs of clear PVC piping, similar in geometry to the existing system. Two different batches of glass slurry were tested: a batch of 50 wt% spherical glass beads and a batch of 50 wt% glass frit in process water. No chemicals such as formic acid was used in slurry, only water and glass formers. The glass beads used for this testing were commercially available borosilicate glass of mesh size -100+200. The glass frit was Frit 418 obtained from DWPF and is nominally -45+200 mesh. The spherical glass beads did not have a negative impact on the frit transfer system. The transferring of the spherical glass beads was much easier than the glass frit. It was difficult to create a plug with glass bead slurry in the pilot transfer system. When a small plug occurred from setting overnight with the spherical glass beads, the plug was easy to displace using only the pump. In the case of creating a man made plug in a vertical line, by filling the line with spherical glass beads and allowing the slurry to settle for days, the plug was easy to remove by using flush water. The glass frit proved to be much more difficult to transfer when compared to the spherical glass beads. The glass frit impacted the transfer system to the point

  18. Sol-Gel Glasses

    Science.gov (United States)

    Mukherjee, S. P.

    1985-01-01

    Multicomponent homogeneous, ultrapure noncrystalline gels/gel derived glasses are promising batch materials for the containerless glass melting experiments in microgravity. Hence, ultrapure, homogeneous gel precursors could be used to: (1) investigate the effect of the container induced nucleation on the glass forming ability of marginally glass forming compositions; and (2) investigate the influence of gravity on the phase separation and coarsening behavior of gel derived glasses in the liquid-liquid immiscibility zone of the nonsilicate systems having a high density phase. The structure and crystallization behavior of gels in the SiO2-GeO2 as a function of gel chemistry and thermal treatment were investigated. As are the chemical principles involved in the distribution of a second network former in silica gel matrix being investigated. The procedures for synthesizing noncrystalline gels/gel-monoliths in the SiO2-GeO2, GeO2-PbO systems were developed. Preliminary investigations on the levitation and thermal treatment of germania silicate gel-monoliths in the Pressure Facility Acoustic Levitator were done.

  19. Bio-Glasses An Introduction

    CERN Document Server

    Jones, Julian

    2012-01-01

    This new work is dedicated to glasses and their variants which can be used as biomaterials to repair diseased and damaged tissues. Bio-glasses are superior to other biomaterials in many applications, such as healing bone by signaling stem cells to become bone cells.   Key features:  First book on biomaterials to focus on bio-glassesEdited by a leading authority on bio-glasses trained by one of its inventors, Dr Larry HenchSupported by the International Commission on Glass (ICG)Authored by members of the ICG Biomedical Glass Committee, with the goal of creating a seamless textb

  20. Glass strengthening and patterning methods

    Science.gov (United States)

    Harper, David C; Wereszczak, Andrew A; Duty, Chad E

    2015-01-27

    High intensity plasma-arc heat sources, such as a plasma-arc lamp, are used to irradiate glass, glass ceramics and/or ceramic materials to strengthen the glass. The same high intensity plasma-arc heat source may also be used to form a permanent pattern on the glass surface--the pattern being raised above the glass surface and integral with the glass (formed of the same material) by use of, for example, a screen-printed ink composition having been irradiated by the heat source.

  1. Glass formation - A contemporary view

    Science.gov (United States)

    Uhlmann, D. R.

    1983-01-01

    The process of glass formation is discussed from several perspectives. Particular attention is directed to kinetic treatments of glass formation and to the question of how fast a given liquid must be cooled in order to form a glass. Specific consideration is paid to the calculation of critical cooling rates for glass formation, to the effects of nucleating heterogeneities and transients in nucleation on the critical cooling rates, to crystallization on reheating a glass, to the experimental determination of nucleation rates and barriers to crystal nucleation, and to the characteristics of materials which are most conducive to glass formation.

  2. Heavy Metal Fluoride Glasses.

    Science.gov (United States)

    1987-04-01

    i 2N E ihhhhh1112h MEmhhhhEEEohhhhE I.’....momo 111111111’-20 LA ’Ll2. AFWL-TR-86-37 AFWL-TR- 86-37 oT C ,l C ’-’ N HEAVY METAL FLUORIDE GLASSES 0nI...Secwrit CkasmfcationJ HEAVY METAL FLUORIDE GLASSES 12. PERSONAL AUTHOR(S) Reisfield, Renata; and Eyal, Mrek 13. TYPE OF REPORT 113b. TIME COVERED 114...glasses containing about 50 mole% of ZrF4 [which can be replaced by HfF 4 or TIF 4 (Refs. 1-3) or heavy metal fluorides based on PbF2 and on 3d-group

  3. Perspectives on spin glasses

    CERN Document Server

    Contucci, Pierluigi

    2013-01-01

    Presenting and developing the theory of spin glasses as a prototype for complex systems, this book is a rigorous and up-to-date introduction to their properties. The book combines a mathematical description with a physical insight of spin glass models. Topics covered include the physical origins of those models and their treatment with replica theory; mathematical properties like correlation inequalities and their use in the thermodynamic limit theory; main exact solutions of the mean field models and their probabilistic structures; and the theory of the structural properties of the spin glass phase such as stochastic stability and the overlap identities. Finally, a detailed account is given of the recent numerical simulation results and properties, including overlap equivalence, ultrametricity and decay of correlations. The book is ideal for mathematical physicists and probabilists working in disordered systems.

  4. Letter report on PCT/Monolith glass ceramic corrosion tests

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Charles L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-24

    The Savannah River National Laboratory (SRNL) is collaborating with personnel from Pacific Northwest National Laboratory (PNNL) to study advanced waste form glass ceramics for immobilization of waste from Used Nuclear Fuel (UNF) separations processes. The glass ceramic waste forms take advantage of both crystalline and glassy phases where ‘troublesome’ elements (e.g., low solubility in glass or very long-lived) partition to highly durable ceramic phases with the remainder of elements residing in the glassy phase. The ceramic phases are tailored to create certain minerals or unique crystalline structures that can host the radionuclides by binding them in their specific crystalline network while not adversely impacting the residual glass network (Crum et al., 2011). Glass ceramics have been demonstrated using a scaled melter test performed in a pilot scale (1/4 scale) cold crucible induction melter (CCIM) (Crum et al., 2014; Maio et al., 2015). This report summarizes recent results from both Phase I and Phase II bench scale tests involving crucible fabrication and corrosion testing of glass ceramics using the Product Consistency Test (PCT). Preliminary results from both Phase I and Phase II bench scale tests involving statistically designed matrices have previously been reported (Crawford, 2013; Crawford, 2014).

  5. Foam Glass for Construction Materials

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund

    2016-01-01

    Foaming is commonly achieved by adding foaming agents such as metal oxides or metal carbonates to glass powder. At elevated temperature, the glass melt becomes viscous and the foaming agents decompose or react to form gas, causing a foamy glass melt. Subsequent cooling to room temperature, result...... in a solid foam glass. The foam glass industry employs a range of different melt precursors and foaming agents. Recycle glass is key melt precursors. Many parameters influence the foaming process and optimising the foaming conditions is very time consuming. The most challenging and attractive goal is to make...... low density foam glass for thermal insulation applications. In this thesis, it is argued that the use of metal carbonates as foaming agents is not suitable for low density foam glass. A reaction mechanism is proposed to justify this result. Furthermore, an in situ method is developed to optimise...

  6. Shattering women's glass ceiling

    OpenAIRE

    Camilleri Podesta, Marie Therese; Duca, Edward

    2013-01-01

    The role of women in academia has always greatly interested me. Several years ago, when I was asked to become Gender Issues Committee chairperson at the University of Malta, I readily accepted. http://www.um.edu.mt/think/shattering-womens-glass-ceiling/

  7. Glass as matter

    DEFF Research Database (Denmark)

    Beim, Anne

    2000-01-01

    Refraiming the Moderns - Substitute Windows and Glass. In general terms, the seminar has contributed to the growing interest in the problems concerning the restoration of Modern Movement architecture. More particularly, it has of course drawn our attention to modern windows, which are increasingly...

  8. What Glass Ceiling?

    Science.gov (United States)

    Lynch, Michael; Post, Katherine

    1996-01-01

    A recent study drawing on data from the Census Bureau and the Bureau of Labor Statistics suggests that the wage gap between men and women has virtually disappeared, and that the so-called "glass ceiling" results more from age and qualifications than from explicit discrimination. (SLD)

  9. Supercooled Liquids and Glasses

    OpenAIRE

    1999-01-01

    In these lectures, which were presented at "Soft and Fragile Matter, Nonequilibrium Dynamics, Metastability and Flow" University of St. Andrews, 8 July - 22 July, 1999, I give an introduction to the physics of supercooled liquids and glasses and discuss some computer simulations done to investigate these systems.

  10. Microchips on glass

    NARCIS (Netherlands)

    Keulemans, M.

    2007-01-01

    Microchips on glass. What about a mobile phone that uses a single microchip to receive all the available frequency bands, plus extras such as television, gps, and Internet access? Or, in due time, see-though implants that will monitor your state of health, and equipment that will let you see through

  11. Stained Glass and Flu

    Centers for Disease Control (CDC) Podcasts

    2017-02-01

    Dr. Robert Webster, an Emeritus member of the Department of Infectious Diseases at St. Jude Children's Research Hospital, discusses his cover art story on stained glass and influenza.  Created: 2/1/2017 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/1/2017.

  12. Triad ''Metal - Enamel - Glass''

    Science.gov (United States)

    Mukhina, T.; Petrova, S.; Toporova, V.; Fedyaeva, T.

    2014-10-01

    This article shows how to change the color of metal and glass. Both these materials are self-sufficient, but sometimes used together. For example, enameling. In this case, the adhesion between metal substrate and stekloobraznae enamel layer, which was conducted on a stretching and a bend, was tested.

  13. Glass ceilings of professionalisation.

    Science.gov (United States)

    Stott, Dawn L

    2016-04-01

    The term glass ceiling is a political term often used to describe an unbreakable barrier that isnot visible with the human eye, but it keeps minorities from rising up i.e. it is a barrier to minoritygroups, in the past (and sometimes still) for women, that stops them from achieving theirtrue potential.

  14. Stained-Glass Pastels

    Science.gov (United States)

    Laird, Shirley

    2009-01-01

    The author has always liked the look of stained-glass windows. Usually the designs are simplified and the shapes are easier for younger students to draw. This technique seemed to be the perfect place for her fifth-graders to try their hand at color mixing. The smaller spaces and simple shapes were just what she needed for this group. Her students…

  15. Stained Glass and Flu

    Centers for Disease Control (CDC) Podcasts

    2016-02-01

    Dr. Robert Webster, an Emeritus member of the Department of Infectious Diseases at St. Jude Children's Research Hospital, discusses his cover art story on stained glass and influenza.  Created: 2/1/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/1/2016.

  16. "Stained Glass" Landscape Windows

    Science.gov (United States)

    Vannata, Janine

    2008-01-01

    Both adults and children alike marvel at the grand vivid stained-glass windows created by American artist Louis Comfort Tiffany. Today he is commonly recognized as one of America's most influential designers and artists throughout the last nineteenth and early twentieth century. In the lesson described in this article, students created their own…

  17. Yesterday's Trash Makes Tomorrow's "Glass"

    Science.gov (United States)

    Wayne, Dale

    2010-01-01

    In this article, the author describes a glass art project inspired by Dale Chihuly. This project uses two-liter plastic soda bottles which are cut apart and trimmed. Applying heat using a hair dryer, the plastic curls and takes an uneven blown-glass quality. The "glass" is then painted using acrylic paint. (Contains 2 resources and 1 online…

  18. Yesterday's Trash Makes Tomorrow's "Glass"

    Science.gov (United States)

    Wayne, Dale

    2010-01-01

    In this article, the author describes a glass art project inspired by Dale Chihuly. This project uses two-liter plastic soda bottles which are cut apart and trimmed. Applying heat using a hair dryer, the plastic curls and takes an uneven blown-glass quality. The "glass" is then painted using acrylic paint. (Contains 2 resources and 1 online…

  19. Molecular Mobility in Sugar Glasses

    NARCIS (Netherlands)

    Dries, van den I.J.

    2000-01-01

    Glasses are liquids that exhibit solid state behavior as a result of their extremely high viscosity. Regarding their application to foods, glasses play a role in the preservation of foods, due to their high viscosity and the concomitant low molecular mobility. This thesis focuses on sugar glasses. S

  20. Glass for Solid State Devices

    Science.gov (United States)

    Bailey, R. F.

    1982-01-01

    Glass film has low intrinsic compressive stress for isolating active layers of magnetic-bubble and other solid-state devices. Solid-state device structure incorporates low-stress glasses as barrier and spacer layers. Glass layers mechanically isolate substrate, conductor, and nickel/iron layers.

  1. Bioactive and Antibacterial Glass Powders Doped with Copper by Ion-Exchange in Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Marta Miola

    2016-05-01

    Full Text Available In this work, two bioactive glass powders (SBA2 and SBA3 were doped with Cu by means of the ion-exchange technique in aqueous solution. SBA2 glass was subjected to the ion-exchange process by using different Cu salts (copper(II nitrate, chloride, acetate, and sulphate and concentrations. Structural (X-ray diffraction-XRD, morphological (Scanning Electron Microscopy-SEM, and compositional (Energy Dispersion Spectrometry-EDS analyses evidenced the formation of crystalline phases for glasses ion-exchanged in copper(II nitrate and chloride solutions; while the ion-exchange in copper(II acetate solutions lead to the incorporation of higher Cu amount than the ion-exchange in copper(II sulphate solutions. For this reason, the antibacterial test (inhibition halo towards S. aureus was performed on SBA2 powders ion-exchanged in copper(II acetate solutions and evidenced a limited antibacterial effect. A second glass composition (SBA3 was developed to allow a greater incorporation of Cu in the glass surface; SBA3 powders were ion-exchanged in copper(II acetate solutions (0.01 M and 0.05 M. Cu-doped SBA3 powders showed an amorphous structure; morphological analysis evidenced a rougher surface for Cu-doped powders in comparison to the undoped glass. EDS and X-ray photoelectron spectroscopy (XPS confirmed the Cu introduction as Cu(II ions. Bioactivity test in simulated body fluid (SBF showed that Cu introduction did not alter the bioactive behaviour of the glass. Finally, inhibition halo test towards S. aureus evidenced a good antimicrobial effect for glass powders ion-exchanged in copper(II acetate solutions 0.05 M.

  2. Glass bead cultivation of fungi

    DEFF Research Database (Denmark)

    Droce, Aida; Sørensen, Jens Laurids; Giese, H.

    2013-01-01

    Production of bioactive compounds and enzymes from filamentous fungi is highly dependent on cultivation conditions. Here we present an easy way to cultivate filamentous fungi on glass beads that allow complete control of nutrient supply. Secondary metabolite production in Fusarium graminearum...... and Fusarium solani cultivated on agar plates, in shaking liquid culture or on glass beads was compared. Agar plate culture and glass bead cultivation yielded comparable results while liquid culture had lower production of secondary metabolites. RNA extraction from glass beads and liquid cultures was easier...... to specific nutrient factors. •Fungal growth on glass beads eases and improves fungal RNA extraction....

  3. Heliostat glass survey and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Lind, M. A.; Russin, J. M.

    1978-01-01

    The glass characterization and specification task included a comprehensive survey of both foreign and domestic sources of low distortion, low iron, .125 nominal flat glass for use in heliostat applications. PNL attempted to determine the availability of production lines, estimate industry interest, lead times, and costs for producing glass for second surface heliostat mirrors for the Barstow pilot plant and future commercial plants. Glass samples representative of the industry production capability were collected and characterized. The results of the survey and analysis were used to generate a specification for the Barstow Pilot Plant glass procurement.

  4. Fluoride release and solubility testing of 4 glass-ionomer restorative materials%四种玻璃离子充填材料释氟性与溶解性的研究

    Institute of Scientific and Technical Information of China (English)

    张海英; 吕松; 侯本祥

    2011-01-01

    Objective To evaluate the fluoride release and the solubility of 4 glass-ionomer restorative materials. Method Five kinds of glass-ionomer restorative materials were used in this study: a traditional glass ionomer cements( SC,Shanghai), two high-viscous glass ionomer cements Fuji Ⅸ ( F9, GC ) and Ketac Moler( KM ,3M) , a resin-modified glass ionomer cements Fuji IILC ( F2LC, GC) , and a composite resin Z100 ( CR, 3M ) . Twelve disk-shaped specimens (10 mm × 1 mm) of each material were prepared,which were divided into fluoride-releaseing testing group and solution testing group equally. Each specimen was immersed in deionized water for 21 days. The cumulative fluoride release was measured by Ion Chromatography. The solubility was determined by weighting the samples before and after water immersion and desiccation,and the ratio (fluoride release / solubility )was computed. Results The fluoride release of 5 kinds of materials showed a decreasing tendency from SC, FM, F9, F2LC to CR. There was no significant difference among F9 and KM,F9 and F2LC in fluoride release(P >0. 05). There were significant differences in solubility among the materials as the following rankings: F2LC > SC > F9 > KM > CR( P SC > F9 > KM > CR. The cumulative fluoride release rates of four glass-ionomers were linear with respect to solubility with r = 0. 9769 (P < 0. 01). Conclusion The fluoride release and the solubility of traditional glass ionomer cements, high-viscous glass ionomer cements and resin-modified glass ionomer cements successively decline. Class ionomer cements with higher fluoride release have lower water stability. The ratio (fluoride release / solubility ) of resin-modified glass ionomer cements is higher than traditional glass ionomer cements and high-viscous glass ionomer cements.%目的 比较4种玻璃离子充填材料短期内氟离子释放能力和溶解性,为临床选择充填材料提供依据.方法 实验选取1种传统型玻璃离子水门汀(SC),2种高强

  5. Low thermal expansion glass ceramics

    CERN Document Server

    1995-01-01

    This book is one of a series reporting on international research and development activities conducted by the Schott group of companies With the series, Schott aims to provide an overview of its activities for scientists, engineers, and managers from all branches of industry worldwide where glasses and glass ceramics are of interest Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated This volume describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization Thus glass ceramics with thermal c...

  6. Production of glass or glass-ceramic to metal seals with the application of pressure

    Science.gov (United States)

    Kelly, M.D.; Kramer, D.P.

    1985-01-04

    In a process for preparing a glass or glass-ceramic to metal seal comprising contacting the glass with the metal and heat-treating the glass and metal under conditions whereby the glass to metal seal is effected and, optionally, the glass is converted to a glass-ceramic, an improvement comprises carrying out the heat-treating step using hot isostatic pressing.

  7. Breaking the glass ceiling.

    Science.gov (United States)

    Lazarus, A

    1997-03-01

    The glass ceiling is a form of organizational bias and discrimination that prevents qualified professionals from achieving positions of top governance and leadership. This article examines glass ceiling barriers that keep physicians from the upper reaches of management. While these factors apply mainly to women and minority physicians in academia, and are attributable to sexual harassment and discrimination, physicians as a class are frequently denied executive management positions. Such denial results from inadequate preparation for a career in health care administration. Important issues in the professional development of physician executives include mentoring, training and education, administrative experience, and cultural and personality factors. All of those must be considered when making the transition from medicine to management.

  8. Glasses for Mali

    CERN Multimedia

    PH Department

    2008-01-01

    We are collecting old pairs of glasses to take out to Mali, where they can be re-used by people there. The price for a pair of glasses can often exceed 3 months salary, so they are prohibitively expensive for many people. If you have any old spectacles you can donate, please put them in the special box in the ATLAS secretariat, Bldg.40-4-D01 before the Christmas closure on 19 December so we can take them with us when we leave for Africa at the end of the month. (more details in ATLAS e-news edition of 29 September 2008: http://atlas-service-enews.web.cern.ch/atlas-service-enews/news/news_mali.php) many thanks! Katharine Leney co-driver of the ATLAS car on the Charity Run to Mali

  9. Supersymmetric Spin Glass

    CERN Document Server

    Gukov, S G

    1997-01-01

    The evidently supersymmetric four-dimensional Wess-Zumino model with quenched disorder is considered at the one-loop level. The infrared fixed points of a beta-function form the moduli space $M = RP^2$ where two types of phases were found: with and without replica symmetry. While the former phase possesses only a trivial fixed point, this point become unstable in the latter phase which may be interpreted as a spin glass phase.

  10. An Insulating Glass Knowledge Base

    Energy Technology Data Exchange (ETDEWEB)

    Michael L. Doll; Gerald Hendrickson; Gerard Lagos; Russell Pylkki; Chris Christensen; Charlie Cureija

    2005-08-01

    This report will discuss issues relevant to Insulating Glass (IG) durability performance by presenting the observations and developed conclusions in a logical sequential format. This concluding effort discusses Phase II activities and focuses on beginning to quantifying IG durability issues while continuing the approach presented in the Phase I activities (Appendix 1) which discuss a qualitative assessment of durability issues. Phase II developed a focus around two specific IG design classes previously presented in Phase I of this project. The typical box spacer and thermoplastic spacer design including their Failure Modes and Effect Analysis (FMEA) and Fault Tree diagrams were chosen to address two currently used IG design options with varying components and failure modes. The system failures occur due to failures of components or their interfaces. Efforts to begin quantifying the durability issues focused on the development and delivery of an included computer based IG durability simulation program. The focus/effort to deliver the foundation for a comprehensive IG durability simulation tool is necessary to address advancements needed to meet current and future building envelope energy performance goals. This need is based upon the current lack of IG field failure data and the lengthy field observation time necessary for this data collection. Ultimately, the simulation program is intended to be used by designers throughout the current and future industry supply chain. Its use is intended to advance IG durability as expectations grow around energy conservation and with the growth of embedded technologies as required to meet energy needs. In addition the tool has the immediate benefit of providing insight for research and improvement prioritization. Included in the simulation model presentation are elements and/or methods to address IG materials, design, process, quality, induced stress (environmental and other factors), validation, etc. In addition, acquired data

  11. Pit and Fissure Sealants with Different Materials: Resin Based x Glass Ionomer Cement – Results after Six Months

    Directory of Open Access Journals (Sweden)

    Priscilla Santana Pinto Gonçalves

    2016-01-01

    Full Text Available Objective: To compare the retention and superficial characteristics between a new resin-modified glass ionomer sealant and resin sealant. In addition, the teeth sealed were compared to partially erupted first molars (control group without sealing in relation to the incidence of dental caries. Material and Methods: Initially, 31 children aged 6-8 years participated in this study. The study children showed caries history, but had at least two healthy first molars. A total of 114 teeth were randomly divided into three groups: Clinpro (n=36, Fluroshield (n=38, and control (n=40. The two sealants were applied under relative isolation after previous prophylaxis and enamel etching with phosphoric acid 35% (15s. Clinical evaluation was performed by two calibrated examiners. They evaluated the retention and surface characteristics of the occlusal surface. Results: Fluroshield® showed significantly greater retention than ClinproTM Varnish® XT (p=0.002. However, the performance analysis of the success and failure of retention presented no significant difference between the materials (p=0.141. Concerning to the surface characteristics, Fluroshield performed better than Clinpro after analyzing the marginal deterioration, marginal discoloration, and superficial discoloration (p<0.05. The surface texture of the materials under study was similar (p=0.071. Sealed groups (Clinpro=Fluroshield showed similar performance in the prevention of dental caries, which was significantly lower than that of control group (p=0.001. Conclusion: Both sealants, Fluroshield® and Clinpro TM Varnish® XT were effective in preventing caries lesion within 6 months, although Fluroshield sealant showed better clinical retention.

  12. Transferability of glass lens molding

    Science.gov (United States)

    Katsuki, Masahide

    2006-02-01

    Sphere lenses have been used for long time. But it is well known that sphere lenses theoretically have spherical aberration, coma and so on. And, aspheric lenses attract attention recently. Plastic lenses are molded easily with injection machines, and are relatively low cost. They are suitable for mass production. On the other hand, glass lenses have several excellent features such as high refractive index, heat resistance and so on. Many aspheric glass lenses came to be used for the latest digital camera and mobile phone camera module. It is very difficult to produce aspheric glass lenses by conventional process of curve generating and polishing. For the solution of this problem, Glass Molding Machine was developed and is spreading through the market. High precision mold is necessary to mold glass lenses with Glass Molding Machine. The mold core is ground or turned by high precision NC aspheric generator. To obtain higher transferability of the mold core, the function of the molding machine and the conditions of molding are very important. But because of high molding temperature, there are factors of thermal expansion and contraction of the mold and glass material. And it is hard to avoid the factors. In this session, I introduce following items. [1] Technology of glass molding and the machine is introduced. [2] The transferability of glass molding is analyzed with some data of glass lenses molded. [3] Compensation of molding shape error is discussed with examples.

  13. Bioactive glass in tissue engineering

    Science.gov (United States)

    Rahaman, Mohamed N.; Day, Delbert E.; Bal, B. Sonny; Fu, Qiang; Jung, Steven B.; Bonewald, Lynda F.; Tomsia, Antoni P.

    2011-01-01

    This review focuses on recent advances in the development and use of bioactive glass for tissue engineering applications. Despite its inherent brittleness, bioactive glass has several appealing characteristics as a scaffold material for bone tissue engineering. New bioactive glasses based on borate and borosilicate compositions have shown the ability to enhance new bone formation when compared to silicate bioactive glass. Borate-based bioactive glasses also have controllable degradation rates, so the degradation of the bioactive glass implant can be more closely matched to the rate of new bone formation. Bioactive glasses can be doped with trace quantities of elements such as Cu, Zn and Sr, which are known to be beneficial for healthy bone growth. In addition to the new bioactive glasses, recent advances in biomaterials processing have resulted in the creation of scaffold architectures with a range of mechanical properties suitable for the substitution of loaded as well as non-loaded bone. While bioactive glass has been extensively investigated for bone repair, there has been relatively little research on the application of bioactive glass to the repair of soft tissues. However, recent work has shown the ability of bioactive glass to promote angiogenesis, which is critical to numerous applications in tissue regeneration, such as neovascularization for bone regeneration and the healing of soft tissue wounds. Bioactive glass has also been shown to enhance neocartilage formation during in vitro culture of chondrocyte-seeded hydrogels, and to serve as a subchondral substrate for tissue-engineered osteochondral constructs. Methods used to manipulate the structure and performance of bioactive glass in these tissue engineering applications are analyzed. PMID:21421084

  14. Analytical Plan for Roman Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Strachan, Denis M.; Buck, Edgar C.; Mueller, Karl T.; Schwantes, Jon M.; Olszta, Matthew J.; Thevuthasan, Suntharampillai; Heeren, Ronald M.

    2011-01-01

    Roman glasses that have been in the sea or underground for about 1800 years can serve as the independent “experiment” that is needed for validation of codes and models that are used in performance assessment. Two sets of Roman-era glasses have been obtained for this purpose. One set comes from the sunken vessel the Iulia Felix; the second from recently excavated glasses from a Roman villa in Aquileia, Italy. The specimens contain glass artifacts and attached sediment or soil. In the case of the Iulia Felix glasses quite a lot of analytical work has been completed at the University of Padova, but from an archaeological perspective. The glasses from Aquileia have not been so carefully analyzed, but they are similar to other Roman glasses. Both glass and sediment or soil need to be analyzed and are the subject of this analytical plan. The glasses need to be analyzed with the goal of validating the model used to describe glass dissolution. The sediment and soil need to be analyzed to determine the profile of elements released from the glass. This latter need represents a significant analytical challenge because of the trace quantities that need to be analyzed. Both pieces of information will yield important information useful in the validation of the glass dissolution model and the chemical transport code(s) used to determine the migration of elements once released from the glass. In this plan, we outline the analytical techniques that should be useful in obtaining the needed information and suggest a useful starting point for this analytical effort.

  15. Characterization and Conduction Mechanism of Highly Conductive Vanadate Glass

    Directory of Open Access Journals (Sweden)

    Tetsuaki Nishida

    2015-12-01

    Full Text Available This paper reviews recent studies of highly conductive barium iron vanadate glass with a composition of 20 BaO ∙ 10 Fe2O3 ∙ 70 V2O5 (in mol %. Isothermal annealing of the vanadate glass for several ten minutes at a given temperature, higher than glass transition temperature or crystallization temperature, caused an increase in σ. Substitution of CuI (3d10, ZnII (3d10 and CuII (3d9 for FeIII (3d5 was investigated to elucidate the effect of electron configuration on the conductivity (σ. A marked decrease in the activation energy of conduction (Ea was also observed after the annealing. Values of Ea were correlated to the energy gap between the donor level and the conduction band (CB in the n-type semiconductor model. Isothermal annealing of ZnII-substituted vanadate glass (20 BaO ∙ 5 ZnO ∙ 5 Fe2O3 ∙ 70 V2O5 at 450 °C for 30 min showed an increase in σ from 2.5 × 10–6 to 2.1 × 10–1 S cm–1, which was one order of magnitude larger than that of non-substituted vanadate glass (3.4 × 10–2 S cm–1. Under the same annealing condition, σ’s of 2.0 × 10–1 and 3.2 × 10–1 S cm–1 were observed for 20 BaO ∙ 5 Cu2O ∙ 5 Fe2O3 ∙ 70 V2O5 and 20 BaO ∙ 5 CuO ∙ 5 Fe2O3 ∙ 70 V2O5 glasses, respectively. These results demonstrate an increase in the carrier (electron density in the CB, primarily composed of anti-bonding 4s-orbitals.

  16. NEW ERBIUM DOPED ANTIMONY GLASSES FOR LASER AND GLASS AMPLIFICATION

    Directory of Open Access Journals (Sweden)

    B. Tioua

    2015-07-01

    Full Text Available Because of the special spectroscopic properties of the rare earth ions, rare earth doped glasses are widely used in bulk and fiber lasers or amplifiers. The modelling of lasers and searching for new laser transitions require a precise knowledge of the spectroscopic properties of rare earth ions in different host glasses. In this poster will offer new doped erbium glasses synthesized in silicate crucibles were obtained in the combination Sb2O3-WO3-Na2O. Several properties are measured and correlated with glass compositions. The absorption spectral studies have been performed for erbium doped glasses. The intensities of various absorption bands of the doped glasses are measured and the Judd-Ofelt parameters have been computed. From the theory of Judd-Ofelt, various radiative properties, such as transition probability, branching ratio and radiative life time for various emission levels of these doped glasses have been determined and reported. These results confirm the ability of antimony glasses for glass amplification.

  17. NEW ERBIUM DOPED ANTIMONY GLASSES FOR LASER AND GLASS AMPLIFICATIONmplification

    Directory of Open Access Journals (Sweden)

    B. Tioua

    2012-06-01

    Full Text Available Because of the special spectroscopic properties of the rare earth ions, rare earth doped glasses are widely used in bulk and fiber lasers or amplifiers. The modelling of lasers and searching for new laser transitions require a precise knowledge of the spectroscopic properties of rare earth ions in different host glasses. in this poster will offer new doped erbium glasses synthesized in silicate crucibles were obtained in the combination Sb2O3-WO3-Na2O. Several properties are measured and correlated with glass compositions. The absorption spectral studies have been performed for erbium doped glasses. The intensities of various absorption bands of the doped glasses are measured and the Judd-Ofelt parameters have been computed. From the theory of Judd-Ofelt, various radiative properties, such as transition probability, branching ratio and radiative life time for various emission levels of these doped glasses have been determined and reported. These results confirm the ability of antimony glasses for glass amplification.

  18. Analysis of glass fibre sizing

    DEFF Research Database (Denmark)

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

    2014-01-01

    Glass fibre reinforced polymer composites are widely used for industrial and engineering applications which include construction, aerospace, automotive and wind energy industry. During the manufacturing glass fibres, they are surface-treated with an aqueous solution. This process and the treated...... surfaces are called sizing. The sizing influences the properties of the interface between fibres and a matrix, and subsequently affects mechanical properties of composites. In this work the sizing of commercially available glass fibres was analysed so as to study the composition and chemical structures....... Soxhlet extraction was used to extract components of the sizing from the glass fibres. The glass fibres, their extracts and coated glass plates were analysed by Thermo-Gravimetric Analysis combined with a mass spectrometer (TGA-MS), and Attenuated Total Reflectance Fourier Transform Infrared (ATR...

  19. Low Thermal Expansion Glass Ceramics

    CERN Document Server

    Bach, Hans

    2005-01-01

    This book appears in the authoritative series reporting the international research and development activities conducted by the Schott group of companies. This series provides an overview of Schott's activities for scientists, engineers, and managers from all branches of industry worldwide in which glasses and glass ceramics are of interest. Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated. This new extended edition describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics. The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions. Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization. Thus g...

  20. Who will buy smart glasses?

    DEFF Research Database (Denmark)

    Rauschnabel, Philipp; Brem, Alexander; Ivens, Bjørn S.

    2015-01-01

    Recent market studies reveal that augmented reality (AR) devices, such as smart glasses, will substantially influence the media landscape. Yet, little is known about the intended adoption of smart glasses, particularly: Who are the early adopters of such wearables? We contribute to the growing body...... of research that investigates the role of personality in predicting media usage by analyzing smart glasses, particularly Google Glass. First, we integrate AR devices into the current evolution of media and technologies. Then, we draw on the Big Five Model of human personality and present the results from two...... studies that investigate the direct and moderating effects of human personality on the awareness and innovation adoption of smart glasses. Our results show that open and emotionally stable consumers tend to be more aware of Google Glass. Consumers who perceive the potential for high functional benefits...

  1. Physical chemistry of glass fracture

    Energy Technology Data Exchange (ETDEWEB)

    Michalske, T.A. [Sandia National Laboratories, Albuquerque, NM (United States)

    1993-12-31

    Since silica glass is a brittle material, its susceptibility to fracture often limits its use in technological applications. Previous studies have demonstrated that the fracture resistance of silica glass is decreased greatly by the presence of chemically reactive species such as water. By studying the effect of controlled amounts of reactive gases on the fracture rate in silica glass, the authors have developed chemical kinetics based models to describe the molecular level processes that lead to stress corrosion fracture of glass. A key aspect of our chemical kinetics based model is the measurement of the stress dependence for the hydrolysis of siloxane bonds. The authors derive the stress dependence for hydrolysis from reaction rate studies that are conducted on strained cyclosiloxane model compounds. The chemical kinetic parameter derived from model compounds is used to successfully predict the fracture behavior of bulk silica glass and the mechanical fatigue of high-strength silica glass fibers in various reactive chemical environments.

  2. Advances in Glass Ionomer Cements

    OpenAIRE

    KAYA, Dt. Tuğba; TİRALİ, Yard. Doç. Dr. Resmiye Ebru

    2013-01-01

    In recent years there have been a number of innovations and developments with respect to glass ionomer cements and their applications in clinical dentistry. This article considers some of the recent outstanding studies regarding the field of glass ionomer cement applications, adhesion and setting mechanisms, types, advantage and disadvantages among themselves and also to enhance the physical and antibacterial properties under the title of 'Advances in Glass Ionomer Cements'. As their biologic...

  3. Structural color from colloidal glasses

    Science.gov (United States)

    Magkiriadou, Sofia

    When a material has inhomogeneities at a lengthscale comparable to the wavelength of light, interference can give rise to structural colors: colors that originate from the interaction of the material's microstructure with light and do not require absorbing dyes. In this thesis we study a class of these materials, called photonic glasses, where the inhomogeneities form a dense and random arrangement. Photonic glasses have angle-independent structural colors that look like those of conventional dyes. However, when this work started, there was only a handful of colors accessible with photonic glasses, mostly hues of blue. We use various types of colloidal particles to make photonic glasses, and we study, both theoretically and experimentally, how the optical properties of these glasses relate to their structure and constituent particles. Based on our observations from glasses of conventional particles, we construct a theoretical model that explains the scarcity of yellow, orange, and red photonic glasses. Guided by this model, we develop novel colloidal systems that allow a higher degree of control over structural color. We assemble glasses of soft, core-shell particles with scattering cores and transparent shells, where the resonant wavelength can be tuned independently of the reflectivity. We then encapsulate glasses of these core-shell particles into emulsion droplets of tunable size; in this system, we observe, for the first time, angle-independent structural colors that cover the entire visible spectrum. To enhance color saturation, we begin experimenting with inverse glasses, where the refractive index of the particles is lower than the refractive index of the medium, with promising results. Finally, based on our theoretical model for scattering from colloidal glasses, we begin an exploration of the color gamut that could be achieved with this technique, and we find that photonic glasses are a promising approach to a new type of long-lasting, non-toxic, and

  4. Microsheet Glass In Solar Concentrators

    Science.gov (United States)

    Richter, Scott W.

    1993-01-01

    Microsheet glass used as highly protective covering material for developmental concentrating reflectors for solar power systems. Together with other materials, possible to fabricate lightweight, highly reflective, accurate, and long-lived concentrators. Desirable properties include durability and smoothness. Glass not affected by ultraviolet radiation, and not degraded by atomic oxygen, found in low orbits around Earth. Though concentrators intended for use in outer space, noteworthy that terrestrial concentrator fabricated with glass sheet 0.7 mm thick.

  5. Toughness of Bulk Metallic Glasses

    Directory of Open Access Journals (Sweden)

    Shantanu V. Madge

    2015-07-01

    Full Text Available Bulk metallic glasses (BMGs have desirable properties like high strength and low modulus, but their toughness can show much variation, depending on the kind of test as well as alloy chemistry. This article reviews the type of toughness tests commonly performed and the factors influencing the data obtained. It appears that even the less-tough metallic glasses are tougher than oxide glasses. The current theories describing the links between toughness and material parameters, including elastic constants and alloy chemistry (ordering in the glass, are discussed. Based on the current literature, a few important issues for further work are identified.

  6. Crystallization of copper metaphosphate glass

    Science.gov (United States)

    Bae, Byeong-Soo; Weinberg, Michael C.

    1993-01-01

    The effect of the valence state of copper in copper metaphosphate glass on the crystallization behavior and glass transition temperature has been investigated. The crystallization of copper metaphosphate is initiated from the surface and its main crystalline phase is copper metaphosphate (Cu(PO)3),independent of the (Cu sup 2+)/(Cu(total)). However, the crystal morphology, the relative crystallization rates, and their temperature dependences are affected by the (Cu sup 2+)/(Cu (total)) ratio in the glass. On the other hand, the totally oxidized glass crystallizes from all over the surface. The relative crystallization rate of the reduced glass to the totally oxidized glass is large at low temperature, but small at high temperature. The glass transition temperature of the glass increases as the (Cu sup 2+)/(Cu(total)) ratio is raised. It is also found that the atmosphere used during heat treatment does not influence the crystallization of the reduced glass, except for the formation of a very thin CuO surface layer when heated in air.

  7. Halide laser glasses

    Energy Technology Data Exchange (ETDEWEB)

    Weber, M.J.

    1982-01-14

    Energy storage and energy extraction are of prime importance for efficient laser action and are affected by the line strengths and linewidths of optical transitions, excited-state lifetimes, nonradiative decay processes, spectroscopic inhomogeneities, nonlinear refractive index, and damage threshold. These properties are all host dependent. To illustrate this, the spectroscopic properties of Nd/sup 3 +/ have been measured in numerous oxide, oxyhalide, and halide glasses. A table summarizes the reported ranges of stimulated emission cross sections, peak wavelengths, linewidths, and radiative lifetimes associated with the /sup 4/F/sub 3/2/ ..-->.. /sup 4/I/sub 11/2/ lasing transition.

  8. Examination of glass-silicon and glass-glass bonding techniques for microfluidic systems

    Energy Technology Data Exchange (ETDEWEB)

    Raley, N.F.; Davidson, J.C.; Balch, J.W.

    1995-10-23

    We report here on the results of experiments concerning particular bonding processes potentially useful for ultimate miniaturization of microfluidic systems. Direct anodic bonding of continuous thin pyrex glass of 250 {mu}m thickness to silicon substrates gives multiple, large voids in the glass. Etchback of thick glass of 1200 {mu}m thickness bonded to silicon substrates gives thin continuous glass layers of 189 {mu}m thickness without voids over areas of 5 cm {times} 12 cm. Glass was also successfully bonded to glass by thermal bonding at 800{degrees}C over a 5 cm {times} 7 cm area. Anticipated applications include microfabricated DNA sequencing, flow injection analysis, and liquid and gas chromatography microinstruments.

  9. Quantitative Evaluation by Glucose Diffusion of Microleakage in Aged Calcium Silicate-Based Open-Sandwich Restorations

    Directory of Open Access Journals (Sweden)

    S. Koubi

    2012-01-01

    Full Text Available This study compared the in vitro marginal integrity of open-sandwich restorations based on aged calcium silicate cement versus resin-modified glass ionomer cement. Class II cavities were prepared on 30 extracted human third molars. These teeth were randomly assigned to two groups (=10 to compare a new hydraulic calcium silicate cement designed for restorative dentistry (Biodentine, Septodont, Saint Maur des Fossés, France with a resin-modified glass ionomer cement (Ionolux, Voco, Cuxhaven, Germany in open-sandwich restorations covered with a light-cured composite. Positive (=5 and negative (=5 controls were included. The teeth simultaneously underwent thermocycling and mechanocycling using a fatigue cycling machine (1,440 cycles, 5–55°C; 86,400 cycles, 50 N/cm2. The specimens were then stored in phosphate-buffered saline to simulate aging. After 1 year, the teeth were submitted to glucose diffusion, and the resulting data were analyzed with a nonparametric Mann-Whitney test. The Biodentine group and the Ionolux group presented glucose concentrations of 0.074 ± 0.035 g/L and 0.080 ± 0.032 g/L, respectively. No statistically significant differences were detected between the two groups. Therefore, the calcium silicate-based material performs as well as the resin-modified glass ionomer cement in open-sandwich restorations.

  10. Comparison of Leaching Rates of Glass-Ceramic and Glass

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>With the increase of the burn-up of the nuclear fuel, the amounts of the long-lived radionuclides increase. The solubility of actinides such as plutonium in glass is very limited. Glass-ceramic as the new

  11. POROUS WALL, HOLLOW GLASS MICROSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Sexton, W.

    2012-06-30

    Hollow Glass Microspheres (HGM) is not a new technology. All one has to do is go to the internet and Google{trademark} HGM. Anyone can buy HGM and they have a wide variety of uses. HGM are usually between 1 to 100 microns in diameter, although their size can range from 100 nanometers to 5 millimeters in diameter. HGM are used as lightweight filler in composite materials such as syntactic foam and lightweight concrete. In 1968 a patent was issued to W. Beck of the 3M{trademark} Company for 'Glass Bubbles Prepared by Reheating Solid Glass Particles'. In 1983 P. Howell was issued a patent for 'Glass Bubbles of Increased Collapse Strength' and in 1988 H. Marshall was issued a patent for 'Glass Microbubbles'. Now Google{trademark}, Porous Wall, Hollow Glass Microspheres (PW-HGMs), the key words here are Porous Wall. Almost every article has its beginning with the research done at the Savannah River National Laboratory (SRNL). The Savannah River Site (SRS) where SRNL is located has a long and successful history of working with hydrogen and its isotopes for national security, energy, waste management and environmental remediation applications. This includes more than 30 years of experience developing, processing, and implementing special ceramics, including glasses for a variety of Department of Energy (DOE) missions. In the case of glasses, SRS and SRNL have been involved in both the science and engineering of vitreous or glass based systems. As a part of this glass experience and expertise, SRNL has developed a number of niches in the glass arena, one of which is the development of porous glass systems for a variety of applications. These porous glass systems include sol gel glasses, which include both xerogels and aerogels, as well as phase separated glass compositions, that can be subsequently treated to produce another unique type of porosity within the glass forms. The porous glasses can increase the surface area compared to &apos

  12. High-level waste borosilicate glass: A compendium of corrosion characteristics. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Cunnane, J.C. [comp.; Bates, J.K.; Bradley, C.R. [Argonne National Lab., IL (United States)] [and others

    1994-03-01

    The objective of this document is to summarize scientific information pertinent to evaluating the extent to which high-level waste borosilicate glass corrosion and the associated radionuclide release processes are understood for the range of environmental conditions to which waste glass may be exposed in service. Alteration processes occurring within the bulk of the glass (e.g., devitrification and radiation-induced changes) are discussed insofar as they affect glass corrosion.This document is organized into three volumes. Volumes I and II represent a tiered set of information intended for somewhat different audiences. Volume I is intended to provide an overview of waste glass corrosion, and Volume 11 is intended to provide additional experimental details on experimental factors that influence waste glass corrosion. Volume III contains a bibliography of glass corrosion studies, including studies that are not cited in Volumes I and II. Volume I is intended for managers, decision makers, and modelers, the combined set of Volumes I, II, and III is intended for scientists and engineers working in the field of high-level waste.

  13. INORGANIC PHOSPHORS IN GLASS BASED ON LEAD SILICATE GLASSES

    Directory of Open Access Journals (Sweden)

    V. A. Aseev

    2014-09-01

    Full Text Available We created and synthesized luminescent composite of the "phosphor in glass" type, based on the lead-silicate matrix and fine-dispersed powder of cerium-activated yttrium-aluminum garnet crystal. Lead-silicate system (40SiO2- 20PbO-(40-x PbF2-xAlF3, x = 0-25 was chosen as the glassy matrix. Initial glass was reduced to powder (frit for "phosphor in glass" composite with a particle size about 50 µm. Glass frit and powder of commercial YAG:Ce3+ phosphor were mixed in a ratio of 30 to 70 (wt %. Then this composite was pressed in a tablet and sintered on a quartz substrate at 823 К for 30 minutes. Thus, the plane parallel sheet for composite of the "phosphor in glass" was obtained with a diameter equal to 10 mm. For the purpose to reduce the loss of light in the presence of dispersion at a glass-phosphor boundary, optimization of glass mixture was done by adjusting the refractive index. X-ray phase and spectral-luminescent analysis of the derived composite were done. The results of these studies showed that there was no degradation of YAG: Ce powder during sintering. Dependence of luminescence intensity from temperature in the range from room temperature to 473 К was studied. It was shown, that with the phosphor in glass usage thermal quenching of luminescence was reduced in comparison with the silicone. The model of white LED was created with the "phosphor in glass" composite based on lead-silicate glasses with low temperature of vitrifying. The derived LED emits white light with a color temperature of 4370 K, and the luminous efficiency is equal to 58 lm/W. The developed luminescent composite based on the lead-silicate matrix can be used for the production of high-power white light LED.

  14. Surface micromorphological changes of glass ionomer following application of 1.23% acidulated phosphate fluoride: A scanning electron microscope study

    Directory of Open Access Journals (Sweden)

    Ektah Khosla

    2014-01-01

    Conclusion: APF gel caused erosive wear of the GICs esp. Fuji II. Hence, it is advisable to avoid the use of APF containing preparations for regular home use especially in children having glass ionomer restoration. If APF gel is indicated or preferred for professional application, it is recommended to apply glass ionomer varnish on the restored teeth prior to the APF gel application.

  15. Glasses in the D'Orbigny Angrite

    Science.gov (United States)

    Varela, M. E.; Kurat, G.; Brandstätter, F.; Bonnin-Mosbah, M.; Metrich, N.

    2001-03-01

    The D'Orbigny angrite contains abundant glasses, a phase which has not been previously reported from any other angrite. Glasses fill in part open druses and intersticial spaces between major silicates, or occur as glass inclusions in olivine.

  16. Fullerene-doped porous glasses

    Science.gov (United States)

    Joshi, M. P.; Kukreja, L. M.; Rustagi, K. C.

    We report the doping of C60 in porous glass by diffusion in solution phase at room temperature. The presence of C60 in the doped porous glass was confirmed spectroscopically. We also report the changes in optical absorption spectrum and intensity-dependent transmission of 30 ns laser pulses at 527 nm in these materials.

  17. Fullerene-doped porous glasses

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, M.P. [Center for Adv. Technol., Indore (India). Nonlinear Optics Group; Kukreja, L.M. [Center for Adv. Technol., Indore (India). Nonlinear Optics Group; Rustagi, K.C. [Center for Adv. Technol., Indore (India). Nonlinear Optics Group

    1997-07-01

    We report the doping of C{sub 60} in porous glass by diffusion in solution phase at room temperature. The presence of C{sub 60} in the doped porous glass was confirmed spectroscopically. We also report the changes in optical absorption spectrum and intensity-dependent transmission of 30 ns laser pulses at 527 nm in these materials. (orig.)

  18. International Congress on Glass XII

    Energy Technology Data Exchange (ETDEWEB)

    Doremus, R H; LaCourse, W C; Mackenzie, J D; Varner, J R; Wolf, W W [eds.

    1980-01-01

    A total of 158 papers are included under nine headings: structure and glass formation; optical properties; electrical and magnetic properties; mechanical properties and relaxation; mass transport; chemical durability and surfaces; nucleation; crystallization; and glass ceramics; processing; and automatic controls. Separate abstracts were prepared for eight papers; four of the remaining papers had been processed previously for the data base. (DLC)

  19. Molecular mobility in sugar glasses

    NARCIS (Netherlands)

    Dries, van den I.J.

    2000-01-01

    Glasses are liquids that exhibit solid state behavior as a result of their extremely high viscosity. Regarding their application to foods, glasses play a role in the preservation of foods, due to their high viscosity and the concomitant low molecular mobility. This thesis focuses on sugar g

  20. Holder for rotating glass body

    Science.gov (United States)

    Kolleck, Floyd W.

    1978-04-04

    A device is provided for holding and centering a rotating glass body such as a rod or tube. The device includes a tubular tip holder which may be held in a lathe chuck. The device can utilize a variety of centering tips each adapted for a particular configuration, such as a glass O-ring joint or semi-ball joint.

  1. OPAL Various Lead Glass Blocks

    CERN Multimedia

    These lead glass blocks were part of a CERN detector called OPAL (one of the four experiments at the LEP particle detector). OPAL uses some 12 000 blocks of glass like this to measure particle energies in the electromagnetic calorimeter. This detector measured the energy deposited when electrons and photons were slowed down and stopped.

  2. Energetics of glass fragmentation: Experiments on synthetic and natural glasses

    Science.gov (United States)

    Kolzenburg, S.; Russell, J. K.; Kennedy, L. A.

    2013-11-01

    Natural silicate glasses are an essential component of many volcanic rock types including coherent and pyroclastic rocks; they span a wide range of compositions, occur in diverse environments, and form under a variety of pressure-temperature conditions. In subsurface volcanic environments (e.g., conduits and feeders), melts intersect the thermodynamically defined glass transition temperature to form glasses at elevated confining pressures and under differential stresses. We present a series of room temperature experiments designed to explore the fundamental mechanical and fragmentation behavior of natural (obsidian) and synthetic glasses (Pyrex™) under confining pressures of 0.1-100 MPa. In each experiment, glass cores are driven to brittle failure under compressive triaxial stress. Analysis of the load-displacement response curves is used to quantify the storage of energy in samples prior to failure, the (brittle) release of elastic energy at failure, and the residual energy stored in the post-failure material. We then establish a relationship between the energy density within the sample at failure and the grain-size distributions (D-values) of the experimental products. The relationship between D-values and energy density for compressive fragmentation is significantly different from relationships established by previous workers for decompressive fragmentation. Compressive fragmentation is found to have lower fragmentation efficiency than fragmentation through decompression (i.e., a smaller change in D-value with increasing energy density). We further show that the stress storage capacity of natural glasses can be enhanced (approaching synthetic glasses) through heat treatment.

  3. Database and Interim Glass Property Models for Hanford HLW Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, Pavel R; Piepel, Gregory F; Vienna, John D; Cooley, Scott K; Kim, Dong-Sang; Russell, Renee L

    2001-07-24

    The purpose of this report is to provide a methodology for an increase in the efficiency and a decrease in the cost of vitrifying high-level waste (HLW) by optimizing HLW glass formulation. This methodology consists in collecting and generating a database of glass properties that determine HLW glass processability and acceptability and relating these properties to glass composition. The report explains how the property-composition models are developed, fitted to data, used for glass formulation optimization, and continuously updated in response to changes in HLW composition estimates and changes in glass processing technology. Further, the report reviews the glass property-composition literature data and presents their preliminary critical evaluation and screening. Finally the report provides interim property-composition models for melt viscosity, for liquidus temperature (with spinel and zircon primary crystalline phases), and for the product consistency test normalized releases of B, Na, and Li. Models were fitted to a subset of the screened database deemed most relevant for the current HLW composition region.

  4. Glass science tutorial: Lecture No. 7, Waste glass technology for Hanford

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, A.A.

    1995-07-01

    This paper presents the details of the waste glass tutorial session that was held to promote knowledge of waste glass technology and how this can be used at the Hanford Reservation. Topics discussed include: glass properties; statistical approach to glass development; processing properties of nuclear waste glass; glass composition and the effects of composition on durability; model comparisons of free energy of hydration; LLW glass structure; glass crystallization; amorphous phase separation; corrosion of refractories and electrodes in waste glass melters; and glass formulation for maximum waste loading.

  5. Joints in Tempered Glass Using Glass Dowel Discs

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Poulsen, Peter Noe

    One of the major reasons for using glass in structures is its transparency; however, traditional mechanical joints such as friction joints and steel dowel pinned connections are compromising the transparency. The present paper describes a novel joint which is practically maintaining the complete...... transparency of the glass. This is achieved by using a dowel disc made entirely of tempered glass. The concept of the joint is proved by pilot tests and numerical models. From the work it is seen that the load-carrying capacity of such a connection is similar to what is found for traditionally in-plane loaded...

  6. Properties and structural features of iron doped BABAL glasses

    Directory of Open Access Journals (Sweden)

    Reis Signo Tadeu dos

    2003-01-01

    Full Text Available The chemical durability, density and structure of the BABAL glasses with batch compositions (100-x(0.30BaO·0.50B2O3·0.20Al2O3·xFe 2O3 (1 < x < 10 mol%, were investigated using Mössbauer spectroscopy, electron paramagnetic resonance (EPR, X-ray diffraction, Raman and differential thermal analysis (DTA. The chemical durability for the glass of composition 27BaO·45B2O3·18Al 2O3·10Fe2O3 (mol% at 90 °C in distilled water was 700 times lower than that of iron phosphate glass 40Fe2O3·60P2O 5 (mol%. The Mössbauer spectra indicate the presence of iron (II and iron (III in tetrahedral or octahedral coordination. The results obtained from the g ef = 4.3 EPR line are typical of the occurrence of iron (III occupying substitutional sites and the line g ef = 2.0 is related to the association of two or more Fe ions found in the interstices (or holes occupied by the glass modifier cations of the glass network. The paths of X-ray diffraction are typical for glasses based in borate glasses. The Raman spectra showed that the boroxol ring disappears with the increase of iron content, concomitant with the appearance of BO4 and tetraborate structural units. At these conditions, an increase of dissolution rate and clustering of iron ions is observed.

  7. [Respiratory function in glass blowers].

    Science.gov (United States)

    Zuskin, E; Butković, D; Mustajbegović, J

    1992-01-01

    The prevalence of chronic and acute respiratory symptoms and diseases and changes in lung function in a group of 80 glass blowers have been investigated. In addition a group of 80 not exposed workers was used as a control group for respiratory symptoms and diseases. In glass blowers, there was significant increase in prevalence of chronic bronchitis, nasal catarrh, and sinusitis than in the controls. Glass blowers exposed for more and less than 10 years had similar prevalences of respiratory symptoms. A large number of glass blowers complained of acute across-shift symptoms. Significant increase in FVC, FEF50 and FEF25 was documented at the end of the work shift. Comparison with predicted normal values showed that glass blowers had FVC and FEF25 significantly lower than predicted. RV and RV/TLC were significantly increased compared with the predicted normal values. DLCO was within the normal values in most glass blowers. It is concluded that work in the glass blower industry is likely to lead the development of chronic respiratory disorders.

  8. Mesomorphic glass nanocomposites made of metal alkanoates and nanoparticles as emerging nonlinear-optical materials

    Science.gov (United States)

    Garbovskiy, Y.; Klimusheva, G.; Mirnaya, T.

    2016-09-01

    Mesomorphic metal alkanoates is very promising yet overlooked class of nonlinear-optical materials. Metal alkanoates can exhibit a broad variety of condensed states of matter including solid crystals, plastic crystals, lyotropic and thermotropic ionic liquid crystals, liquids, mesomorphic glasses, and Langmuir-Blodgett films. Glass-forming properties of metal alkanoates combined with their use as nano-reactors and anisotropic host open up simple and efficient way to design various photonic nanomaterials. Despite very interesting physics, the experimental data on optical and nonlinearoptical properties of such materials are scarce. The goal of the present paper is to fill the gap by discussing recent advances in the field of photonic materials made of metal alkanoates, organic dyes, and nanoparticles. Optical and nonlinear-optical properties of the following materials are reviewed: (i) mesomorphic glass doped with organic dyes; (ii) smectic glass composed of cobalt alkanoates; (iii) semiconductor nanoparticles embedded in a glassy host; (iv) metal nanoparticles - glass (the cobalt octanoate) nanocomposites.

  9. The molten glass sewing machine

    Science.gov (United States)

    Brun, P.-T.; Inamura, Chikara; Lizardo, Daniel; Franchin, Giorgia; Stern, Michael; Houk, Peter; Oxman, Neri

    2017-04-01

    We present a fluid-instability-based approach for digitally fabricating geometrically complex uniformly sized structures in molten glass. Formed by mathematically defined and physically characterized instability patterns, such structures are produced via the additive manufacturing of optically transparent glass, and result from the coiling of an extruded glass thread. We propose a minimal geometrical model-and a methodology-to reliably control the morphology of patterns, so that these building blocks can be assembled into larger structures with tailored functionally and optically tunable properties. This article is part of the themed issue 'Patterning through instabilities in complex media: theory and applications'.

  10. Who will buy smart glasses?

    DEFF Research Database (Denmark)

    Rauschnabel, Philipp; Brem, Alexander; Ivens, Bjørn S.

    2015-01-01

    studies that investigate the direct and moderating effects of human personality on the awareness and innovation adoption of smart glasses. Our results show that open and emotionally stable consumers tend to be more aware of Google Glass. Consumers who perceive the potential for high functional benefits...... and social conformity of smart glasses are more likely to adopt such wearables. The strength of these effects is moderated by consumers’ individual personality, particularly by their levels of openness to experience, extraversion and neuroticism. This article concludes with a discussion of theoretical...

  11. OPAL 96 Blocks Lead Glass

    CERN Multimedia

    This array of 96 lead glass bricks formed part of the OPAL electromagnetic calorimeter. One half of the complete calorimeter is shown in the picture above. There were 9440 lead glass counters in the OPAL electromagnetic calorimeter. These are made of Schott type SF57 glass and each block weighs about 25 kg and consists of 76% PbO by weight. Each block has a Hamamatsu R2238 photomultiplier glued on to it. The complete detector was in the form of a cylinder 7m long and 6m in diameter. It was used to measure the energy of electrons and photons produced in LEP interactions.

  12. Mineralogical and chemical analyses of ancient glass beads from Taiwan and their implications

    Science.gov (United States)

    Liou, Y. S.; Liu, Y. C.

    2015-12-01

    Large numbers of monochrome glass beads with different colors, shapes, and stylistics excavated from the archaeological sites of Taiwan, which were dated mainly from the 2nd century AD to the early Historical Period of Taiwan. Archaeologically, these glass beads were more prevalent in eastern and northern Taiwan and were generally believed to be non-native, as well as were brought into Taiwan through the maritime exchange and/or trade activities between Taiwan and Southeast Asia/China since the Neolithic Age. Nevertheless, ancient glass beads have been little studies in Taiwan, aspects of these glass beads are not well detailed. In this work, non-destructive micro-Raman spectroscopy and μXRF are used in combination to examine 56 ancient glass beads excavated from six archaeological sites, eastern Taiwan, to unravel the mineralogical and chemical compositions and to help decipher the raw materials used and the provenance of beads. Micro-Raman measurements indicate the presence of hematite, zincite, siderite, sphalerite, lead tin yellow type II, adularia, chalcedony, anatase, rutite, ankerite, graphite, calcite, etc. Hematite, zincite, siderite, sphalerite, lead tin yellow type II, and rutile were found to be colorants/opacifiers. Among these crystalline phases, lead tin yellow type II was first detected in the ancient glass bead unearthed from Taiwan, which is accordant with results of chemical analysis. The chemical results obtained by μXRF show SiO2, Al2O3, Na2O, K2O, MgO, CaO, and PbO as the most abundant oxides. It is found that Na2O, Na2O, K2O, Al2O3, and MgO are the main/minor fluxes. According to the results, the three most frequent types are mineral soda alumina glass, soda plant ash glass, and lead silicate glass. The provenance of ancient beads unearthed from archaeological sites of Taiwan is possibility of multiple sources.

  13. Shattered glass seeking the densest matter: the color glass condensate

    CERN Multimedia

    Appell, D

    2004-01-01

    "Physicists investigating heavy-particle collisions believe they are on the track of a universal form of matter, one common to very high energy particles ranging from protons to heavy nuclei such as uranium. Some think that this matter, called a color glass condensate, may explain new nuclear properties and the process of particle formation during collisions. Experimentalists have recently reported intriguing data that suggest a color glass condensate has actually formed in past work" (1 page)

  14. Water Glass Modification and its Impact on the Mechanical Properties of Moulding Sands

    OpenAIRE

    A. Kmita; B. Hutera

    2013-01-01

    The purpose of the presented experiment was to develop an effective water glass modifier. In the conducted research, an attempt was made to determine the effect of modifier addition on the wettability of quartz grains, viscosity and cohesion of binder and strength RmUof the sand mixture. Water glass modification was carried out with, obtained in electrochemical process [1], colloidal suspension of ZnO nanoparticles in methanol (modifier I) or propanol (modifier II), characterised by a constan...

  15. Climate accounting for waste management, Phase I and II. Summary: Phase 1: Glass Packaging, Metal packaging, paper, cardboard, plastic and wet organic waste. Phase 2: Wood waste and residual waste from households; Klimaregnskap for avfallshaandtering, Fase I og II. Sammendrag: Fase 1: Glassemballasje, metallemballasje, papir, papp, plastemballasje og vaatorganisk avfall. Fase 2: Treavfall og restavfall fra husholdninger

    Energy Technology Data Exchange (ETDEWEB)

    Raadal, Hanne Lerche; Modahl, Ingunn Saur; Lyng, Kari-Anne

    2009-09-15

    Background. On the basis of an increased focus on emissions of greenhouse gases in general, Waste Norway wanted to prepare a climate accounting for waste management in Norway. Oestfoldforskning was engaged to undertake the project. The aim of the project has been to develop a model for the calculation of net greenhouse gas emissions from different waste types of waste glass containers, metal containers, paper, cardboard, plastic, wet organic waste, wood waste and residual waste. The model is based on life cycle methodology and is used to calculate the net greenhouse gas emissions per kg of waste for the various waste management options and waste types, as well as to calculate the net greenhouse gas emissions for waste management for including waste types and quantities of 2006. There is an emphasis on developing a model so that municipalities / waste companies or regions can develop their own climate accounting for waste management in their region, based on site-specific conditions associated with types and amounts of waste, transport distances, type of treatment, exploitation and use of waste generated energy etc. The model can also be used as the basis for the preparation of useful documentation as the basis for information about waste systems utility in general, and as a basis for strategic reviews for Waste Norway and the waste sector in particular. Conclusions: The main conclusions from the project can be summarized as follows: 1. The results of the study clearly shows that to consider only one environmental indicator is too narrow approach to form the basis for decision making for selection of waste management solutions. 2. Net greenhouse gas emissions for waste management varies greatly, both between the different types of waste and treatment methods which are reviewed. The main results of the ranking of management methods in relation to the net greenhouse effect associated with the waste types and treatment methods are as follows: Recycling of materials

  16. Potential and challenges of interdisciplinary research on historical window glass, stained glass and reverse glass paintings

    Science.gov (United States)

    Trümpler, Stefan; Wolf, Sophie; Kessler, Cordula; Goll, Jürg

    The interdisciplinary study of ancient materials has become an increasingly common strategy, mainly because it has proved to be a highly rewarding approach to studying the age, provenance and production of archaeological objects. The results of such an approach sometimes also provide answers to questions relating not only to socio-cultural, economic or technological developments in a particular region or period (trade, innovation, production etc.), but also the conservation of the materials or artefacts in question. A number of analytical methods, ranging from microscopic to elementary analyses, have been successfully applied to determine the nature of materials and technologies used in the production, as well as to identify the provenance of ancient glass. As far as window glass and stained glass is concerned, the study of architectural context and art history - as well as the technological characteristics of materials - has proved to be most helpful in determining history, production and artistic importance of the objects under study. This paper discusses some of the multidisciplinary studies that the Vitrocentre Romont has conducted on early medieval window glass, stained glass and reverse glass paintings and illustrates the potential of a holistic approach in solving questions about materials, techniques, window design and conservation. It also addresses the limitations of the approach, which are often related to finding appropriate (i.e. non-destructive and possibly portable) methods for the analysis of sometimes extremely fragile stained glass windows.

  17. The bearable lightness of all glass structures

    NARCIS (Netherlands)

    Nijsse, R.

    2015-01-01

    This paper is new developments in structural engineering related especially to the use of the material glass. After a philosophical discussion about why glass is the material for the Future, all glass elements and related techniques are presented from which an all glass building can be assembled. To

  18. The Future of all glass structures

    NARCIS (Netherlands)

    Nijsse, R.

    2015-01-01

    This paper is new developments in structural engineering related especially to the use of the material glass. After a philosophical discussion about why glass is the material for the Future, all glass elements and related techniques are presented from which an all glass building can be assembled. To

  19. The structural strength of glass: hidden damage

    NARCIS (Netherlands)

    Veer, F.A.; Rodichev, Y.M.

    2011-01-01

    We discuss “hidden damage” of glass by the rolling process, which results in heterogeneous distribution of microcracks on the edge surface of glass element, which are the fracture source deteriorating glass element strength. It is shown that removal of this damage on the edges of glass elements

  20. Perceptual effects of overlapping curved glass

    NARCIS (Netherlands)

    Cruz, P.J.S.; Veer, F.A.; Carvalho, P.L.L.

    2010-01-01

    The application of glass in contemporary architecture explores perceptual phenomenon that intentionally change the way we experience space. SANAA'S recent work uses glass in a radical way, proposing a renewed approach to transparency. The Toledo Glass Pavilion, with most spaces defined by glass

  1. Perceptual effects of overlapping curved glass

    NARCIS (Netherlands)

    Cruz, P.J.S.; Veer, F.A.; Carvalho, P.L.L.

    2010-01-01

    The application of glass in contemporary architecture explores perceptual phenomenon that intentionally change the way we experience space. SANAA'S recent work uses glass in a radical way, proposing a renewed approach to transparency. The Toledo Glass Pavilion, with most spaces defined by glass wall

  2. The bearable lightness of all glass structures

    NARCIS (Netherlands)

    Nijsse, R.

    2015-01-01

    This paper is new developments in structural engineering related especially to the use of the material glass. After a philosophical discussion about why glass is the material for the Future, all glass elements and related techniques are presented from which an all glass building can be assembled. To

  3. The Future of all glass structures

    NARCIS (Netherlands)

    Nijsse, R.

    2015-01-01

    This paper is new developments in structural engineering related especially to the use of the material glass. After a philosophical discussion about why glass is the material for the Future, all glass elements and related techniques are presented from which an all glass building can be assembled. To

  4. The structural strength of glass: hidden damage

    NARCIS (Netherlands)

    Veer, F.A.; Rodichev, Y.M.

    2011-01-01

    We discuss “hidden damage” of glass by the rolling process, which results in heterogeneous distribution of microcracks on the edge surface of glass element, which are the fracture source deteriorating glass element strength. It is shown that removal of this damage on the edges of glass elements incr

  5. 7 CFR 2902.30 - Glass cleaners.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Glass cleaners. 2902.30 Section 2902.30 Agriculture... Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass... qualifying biobased glass cleaners. By that date, Federal agencies that have the responsibility for...

  6. Faraday Rotator Glass for Laser Application

    Institute of Scientific and Technical Information of China (English)

    JIANG Ya-si; ZHOU Bei-ming; WANG Biao; HU Li-li

    2007-01-01

    Glasses with strong Faraday rotation are interest for laser applications. The principles of diamagnetic and paramagnetic Faraday rotator glasses are described theoretically and experimentally. High performance Tb-paramagnetic glass series were developed and produced at Kigre in the US and SIOM in Shanghai. Large aperture glass disks have been used for high power laser fusion systems.

  7. Surface modification of glass beads with glutaraldehyde: Characterization and their adsorption property for metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Ozmen, Mustafa; Can, Keziban; Akin, Ilker; Arslan, Gulsin [Department of Chemistry, Selcuk University, 42031, Konya (Turkey); Tor, Ali, E-mail: ali.alitor@gmail.com [Department of Environmental Engineering, Selcuk University, Engineering Faculty, Campus, 42031, Konya (Turkey); Cengeloglu, Yunus; Ersoz, Mustafa [Department of Chemistry, Selcuk University, 42031, Konya (Turkey)

    2009-11-15

    In this study, a new material that adsorbs the metal ions was prepared by modification of the glass beads surfaces with glutaraldehyde. First, the glass beads were etched with 4 M NaOH solution. Then, they were reacted with 3-aminopropyl-triethoxysilane (APTES). Finally, silanized glass beads were treated with 25% of glutaraldehyde solution. The characterization studies by using Fourier Transform Infrared Spectroscopy (FT-IR), Thermal Gravimetric Analysis (TGA), elemental analysis and Scanning Electron Microscopy (SEM) indicated that modification of the glass bead surfaces was successfully performed. The adsorption studies exhibited that the modified glass beads could be efficiently used for the removal of the metal cations and anion (chromate ion) from aqueous solutions via chelation and ion-exchange mechanisms. For both Pb(II) and Cr(VI), selected as model ions, the adsorption equilibrium was achieved in 60 min and adsorption of both ions followed the second-order kinetic model. It was found that the sorption data was better represented by the Freundlich isotherm in comparison to the Langmuir and Redlich-Peterson isotherm models. The maximum adsorption capacities for Pb(II) and Cr(VI) were 9.947 and 11.571 mg/g, respectively. The regeneration studies also showed that modified glass beads could be re-used for the adsorption of Pb(II) and Cr(VI) from aqueous solutions over three cycles.

  8. Spin glasses on thin graphs

    CERN Document Server

    Baillie, C F; Johnston, D A; Plechác, P

    1995-01-01

    In a recent paper we found strong evidence from simulations that the Ising antiferromagnet on ``thin'' random graphs - Feynman diagrams - displayed a mean-field spin glass transition. The intrinsic interest of considering such random graphs is that they give mean field results without long range interactions or the drawbacks, arising from boundary problems, of the Bethe lattice. In this paper we reprise the saddle point calculations for the Ising and Potts ferromagnet, antiferromagnet and spin glass on Feynman diagrams. We use standard results from bifurcation theory that enable us to treat an arbitrary number of replicas and any quenched bond distribution. We note the agreement between the ferromagnetic and spin glass transition temperatures thus calculated and those derived by analogy with the Bethe lattice, or in previous replica calculations. We then investigate numerically spin glasses with a plus or minus J bond distribution fo rthe Ising and Q=3,3,10,50 state Potts models, paying particular attention t...

  9. Turning nuclear waste into glass

    Energy Technology Data Exchange (ETDEWEB)

    Pegg, Ian L.

    2015-02-15

    Vitrification has emerged as the treatment option of choice for the most dangerous radioactive waste. But dealing with the nuclear waste legacy of the Cold War will require state-of-the-art facilities and advanced glass formulations.

  10. Imaging spectroscopy based strategies for ceramic glass contaminants removal in glass recycling.

    Science.gov (United States)

    Bonifazi, Giuseppe; Serranti, Silvia

    2006-01-01

    The presence of ceramic glass contaminants in glass recycling plants reduces production quality and increases production costs. The problem of ceramic glass inspection is related to the fact that its detectable physical and pictorial properties are quite similar to those of glass. As a consequence, at the sorting plant scale, ceramic glass looks like normal glass and is detectable only by specialized personnel. In this paper an innovative approach for ceramic glass recognition, based on imaging spectroscopy, is proposed and investigated. In order to define suitable inspection strategies for the separation between useful (glass) and polluting (ceramic glass) materials, reference samples of glass and ceramic glass presenting different colors, thicknesses, shapes and manufacturing processes have been selected. Reflectance spectra have been obtained using two equipment covering the visible and near infrared wavelength ranges (400-1000 and 1000-1700 nm). Results showed as recognition of glass and ceramic glass is possible using selected wavelength ratios, in both visible and near infrared fields.

  11. High insulation foam glass material from waste cathode ray tube panel glass

    DEFF Research Database (Denmark)

    König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

    . In general CRT consists of two types of glasses: barium/strontium containing glass (panel glass) and lead containing glass (funnel and panel glass). In this work we present the possibility to produce high performance insulation material from the recycled lead-free glass. We studied the influence of foaming...... parameters on the characteristics of foamed glass. CRT panel glass was crushed, milled and sieved below 63 m. Activated carbon used as a foaming agent and MnO2 as an ‘oxidizing’ agent were mixed with glass powders by means of a planetary ball mill. Foaming effect was observed in the temperature range...

  12. Glass microspheres for medical applications

    Science.gov (United States)

    Conzone, Samuel David

    Radioactive dysprosium lithium borate glass microspheres have been developed as biodegradable radiation delivery vehicles for the radiation synovectomy treatment of rheumatoid arthritis. Once injected into a diseased joint, the microspheres deliver a potent dose of radiation to the diseased tissue, while a non-uniform chemical reaction converts the glass into an amorphous, porous, hydrated dysprosium phosphate reaction product. The non-radioactive, lithium-borate component is dissolved from the glass (up to 94% weight loss), while the radioactive 165Dy reacts with phosphate anions in the body fluids, and becomes "chemically" trapped in a solid, dysprosium phosphate reaction product that has the same size as the un-reacted glass microsphere. Ethylene diamine tetraacetate (EDTA) chelation therapy can be used to dissolve the dysprosium phosphate reaction product after the radiation delivery has subsided. The dysprosium phosphate reaction product, which formed in vivo in the joint of a Sprague-Dawley rat, was dissolved by EDTA chelation therapy in 100 Gy) of localized beta radiation to a treatment site within the body, followed by complete biodegradability. The non-uniform reaction process is a desirable characteristic for a biodegradable radiation delivery vehicle, but it is also a novel material synthesis technique that can convert a glass to a highly porous materials with widely varying chemical composition by simple, low-temperature, glass/solution reaction. The reaction product formed by nonuniform reaction occupies the same volume as the un-reacted glass, and after drying for 1 h at 300°C, has a specific surface area of ≈200 m2/g, a pore size of ≈30 nm, and a nominal crushing strength of ≈10 MPa. Finally, rhenium glass microspheres, composed of micron-sized, metallic rhenium particles dispersed within a magnesium alumino borate glass matrix were produced by sintering ReO2 powder and glass frit at 1050°C. A 50 mg injection of radioactive rhenium glass

  13. Do atmospheric aerosols form glasses?

    OpenAIRE

    Zobrist, B.; Marcolli, C.; Pedernera, D. A.; Koop, T.

    2008-01-01

    A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline) solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg

  14. Random Fields and Spin Glasses

    Science.gov (United States)

    De Dominicis, Cirano; Giardina, Irene

    2010-06-01

    1. A brief introduction; 2. The Random Field Ising model; 3. The dynamical approach; 4. The p=2 spherical model; 5. Mean field spin glasses: one-step RSB; 6. The Sherrington-Kirkpatrick model; 7. Mean field via TAP equations; 8. Spin glass above D=6; 9. Propagators, mostly replicon; 10. Ward-Takahashi identities and Goldstone modes; 11. Alternative approaches and conclusions; Appendices; Index.

  15. Rhenium volatilization in waste glasses

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Kai; Pierce, David A. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Hrma, Pavel, E-mail: pavel.hrma@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Schweiger, Michael J. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Kruger, Albert A. [U.S. Department of Energy, Office of River Protection, Richland, WA 99352 (United States)

    2015-09-15

    Highlights: • Re did not volatilize from a HLW feed until 1000 °C. • Re began to volatilize from LAW feeds at ∼600 °C. • The vigorous foaming and generation of gases from salts enhanced Re evaporation in LAW feeds. • The HLW glass with less foaming and salts is a promising medium for Tc immobilization. - Abstract: We investigated volatilization of rhenium (Re), sulfur, cesium, and iodine during the course of conversion of high-level waste melter feed to glass and compared the results for Re volatilization with those in low-activity waste borosilicate glasses. Whereas Re did not volatilize from high-level waste feed heated at 5 K min{sup −1} until 1000 °C, it began to volatilize from low-activity waste borosilicate glass feeds at ∼600 °C, a temperature ∼200 °C below the onset temperature of evaporation from pure KReO{sub 4}. Below 800 °C, perrhenate evaporation in low-activity waste melter feeds was enhanced by vigorous foaming and generation of gases from molten salts as they reacted with the glass-forming constituents. At high temperatures, when the glass-forming phase was consolidated, perrhenates were transported to the top surface of glass melt in bubbles, typically together with sulfates and halides. Based on the results of this study (to be considered preliminary at this stage), the high-level waste glass with less foaming and salts appears a promising medium for technetium immobilization.

  16. A combination of a connector for glass elements and such glass elements

    NARCIS (Netherlands)

    Veer, F.A.

    2014-01-01

    A combination of a connector for glass elements and such glass elements to provide a loadbearing glass construc- tion that comprises at least one glass post and at least one glass beam that are arranged adjacent to each other, wherein the connector is arranged to provide a rotationally fixed

  17. Production of lightweight foam glass (invited talk)

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    The foam glass production allows low cost recycling of postconsumer glass and industrial waste materials as foaming agent or as melt resource. Foam glass is commonly produced by utilising milled glass mixed with a foaming agent. The powder mixture is heat-treated to around 10^3.7 – 10^6 Pa s, which...... result in viscous sintering and subsequent foaming of the glass melt. The porous glass melt is cooled down to room temperature to freeze-in the foam structure. The resulting foam glass is applied in constructions as a light weight material to reduce load bearing capacity and as heat insulating material...... in buildings and industry. We foam panel glass from old televisions with different foaming agents. We discuss the foaming ability and the foaming mechanism of different foaming systems. We compare several studies to define a viscous window for preparing low density foam glass. However, preparing foam glass...

  18. Heliostat glass survey and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lind, M.A.; Rusin, J.M.

    1978-09-01

    A comprehensive survey of both foreign and domestic sources of low distortion, high transmission flat glass with a nominal thickness of 3 mm was undertaken. The purpose of the survey was to determine the characteristics, availability and cost of glass for use in second surface heliostat mirrors for the Barstow pilot plant and future commercial central receiver plants. Information obtained from the manufacturers and the results of investigations performed at Sandia Laboratories at Albuquerque and Livermore were compiled with the PNL characterization data to generate the specifications for the GFE glass to be used in the Barstow pilot plant. During the course of the survey, nine of the major glass manufacturers were contacted for information and assistance. These manufacturers were PPG, Corning, Ford, LOF, CE, ASG, Fourco, Schott, and Guardian. Eleven different flat glass samples from seven of the domestic sources and one foreign source were characterized for solar transmittance, flatness and durability. The samples were representative of four different manufacturing processes: float, fusion, rolled, and twin ground. The results and implications of these glass characterization studies and a brief summary of the manufacturer survey are presented.

  19. BNFL Report Glass Formers Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.F.

    2000-07-27

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. The problems might include arching or ratholing in the silo/hopper. In addition, all of the blends may require consideration for their handling.

  20. BNFL Report Glass Formers Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.F.

    2000-07-27

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. In addition, all of the blends may require consideration for their handling. A number of engineering considerations and recommendations were prepared based on the experimental findings, experience, and other process considerations. Recommendations for future testing are included. In conjunction with future work, it is recommended that a professional consultant be engaged to guide and assist with testing and design input.

  1. BNFL Report Glass Formers Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.F.

    2000-07-27

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. In addition, all of the blends may require consideration for their handling. A number of engineering considerations and recommendations were prepared based on the experimental findings, experience, and other process considerations. Recommendations for future testing are included. In conjunction with future work, it is recommended that a professional consultant be engaged to guide and assist with testing and design input.

  2. Bioactive glasses: Frontiers and challenges

    Directory of Open Access Journals (Sweden)

    Larry L. Hench

    2015-11-01

    Full Text Available Bioactive glasses were discovered in 1969 and provided for the first time an alternative to nearly inert implant materials. Bioglass formed a rapid, strong and stable bond with host tissues. This article examines the frontiers of research crossed to achieve clinical use of bioactive glasses and glass-ceramics. In the 1980’s it was discovered that bioactive glasses could be used in particulate form to stimulate osteogenesis, which thereby led to the concept of regeneration of tissues. Later, it was discovered that the dissolution ions from the glasses behaved like growth factors, providing signals to the cells. This article summarizes the frontiers of knowledge crossed during four eras of development of bioactive glasses that have led from concept of bioactivity to widespread clinical and commercial use, with emphasis on the first composition, 45S5 Bioglass®. The four eras are: a discovery; b clinical application; c tissue regeneration; and d innovation. Questions still to be answered for the fourth era are included to stimulate innovation in the field and exploration of new frontiers that can be the basis for a general theory of bioactive stimulation of regeneration of tissues and application to numerous clinical needs.

  3. Experimental Design for Hanford Low-Activity Waste Glasses with High Waste Loading

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cooley, Scott K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Vienna, John D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Crum, Jarrod V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-24

    This report discusses the development of an experimental design for the initial phase of the Hanford low-activity waste (LAW) enhanced glass study. This report is based on a manuscript written for an applied statistics journal. Appendices A, B, and E include additional information relevant to the LAW enhanced glass experimental design that is not included in the journal manuscript. The glass composition experimental region is defined by single-component constraints (SCCs), linear multiple-component constraints (MCCs), and a nonlinear MCC involving 15 LAW glass components. Traditional methods and software for designing constrained mixture experiments with SCCs and linear MCCs are not directly applicable because of the nonlinear MCC. A modification of existing methodology to account for the nonlinear MCC was developed and is described in this report. One of the glass components, SO3, has a solubility limit in glass that depends on the composition of the balance of the glass. A goal was to design the experiment so that SO3 would not exceed its predicted solubility limit for any of the experimental glasses. The SO3 solubility limit had previously been modeled by a partial quadratic mixture model expressed in the relative proportions of the 14 other components. The partial quadratic mixture model was used to construct a nonlinear MCC in terms of all 15 components. In addition, there were SCCs and linear MCCs. This report describes how a layered design was generated to (i) account for the SCCs, linear MCCs, and nonlinear MCC and (ii) meet the goals of the study. A layered design consists of points on an outer layer, and inner layer, and a center point. There were 18 outer-layer glasses chosen using optimal experimental design software to augment 147 existing glass compositions that were within the LAW glass composition experimental region. Then 13 inner-layer glasses were chosen with the software to augment the existing and outer

  4. Operational Modal Analysis on laminated glass beams

    OpenAIRE

    López Aenlle, Manuel; Fernández, Pelayo; Villa García, Luis Manuel; Barredo Egusquiza, Josu; Hermanns, Lutz Karl Heinz; Fraile de Lerma, Alberto

    2011-01-01

    Laminated glass is a sandwich element consisting of two or more glass sheets, with one or more interlayers of polyvinyl butyral (PVB). The dynamic response of laminated glass beams and plates can be predicted using analytical or numerical models in which the glass and the PVB are usually modelled as linear-elastic and linear viscoelastic materials, respectively. In this work the dynamic behavior of laminated glass beams are predicted using a finite element model and the analytical model ...

  5. Secondary caries formation in vitro around glass ionomer-lined amalgam and composite restorations.

    Science.gov (United States)

    Dionysopoulos, P; Kotsanos, N; Papadogianis, Y

    1996-08-01

    The aim of this in vitro secondary caries study was to examine the glass-ionomer liner's effect on wall-lesion inhibition when a conventional and a light-cured glass ionomer liner was placed under amalgam and composite resin restorations. Class V preparations in extracted upper premolars were used and ten restorations were used for each of the following groups: (i) two layers of copal varnish and amalgam; (ii) conventional glass-ionomer and amalgam; (iii) light-cured glass-ionomer and amalgam; (iv) bonding agent and light-cured composite resin; (v) conventional glass-ionomer, bonding agent and light-cured composite resin; (vi) light-cured glass-ionomer, extended 0.3 mm short of the enamel margin bonding agent and light-cured composite resin; and (vii) light-cured glass-ionomer, extended 1 mm short of the enamel margin, bonding agent and light-cured composite resin. The teeth were thermocycled and artificial caries were created using an acid-gel. The results of this study showed that artificial recurrent caries can be reduced significantly (P amalgam restorations. The results also showed that when the light-cured glass-ionomer liner was placed 0.3 mm from the cavosurface margin under composite resin restoration, the artificial recurrent caries reduced significantly (P < 0.05).

  6. Natural analogues of nuclear waste glass corrosion.

    Energy Technology Data Exchange (ETDEWEB)

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-06

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses.

  7. Structural relaxation and thermal conductivity of high-pressure formed, high-density di-n-butyl phthalate glass and pressure induced departures from equilibrium state

    Science.gov (United States)

    Johari, G. P.; Andersson, Ove

    2017-06-01

    We report a study of structural relaxation of high-density glasses of di-n-butyl phthalate (DBP) by measuring thermal conductivity, κ, under conditions of pressure and temperature (p,T) designed to modify both the vibrational and configurational states of a glass. Various high-density glassy states of DBP were formed by (i) cooling the liquid under a fixed high p and partially depressurizing the glass, (ii) isothermal annealing of the depressurized glass, and (iii) pressurizing the glass formed by cooling the liquid under low p. At a given low p, κ of the glass formed by cooling under high p is higher than that of the glass formed by cooling under low p, and the difference increases as glass formation p is increased. κ of the glass formed under 1 GPa is ˜20% higher at ambient p than κ of the glass formed at ambient p. On heating at low p, κ decreases until the glass to liquid transition range is reached. This is the opposite of the increase in κ observed when a glass formed under a certain p is heated under the same p. At a given high p, κ of the low-density glass formed by cooling at low p is lower than that of the high-density glass formed by cooling at that high p. On heating at high p, κ increases until the glass to liquid transition range is reached. The effects observed are due to a thermally assisted approach toward equilibrium at p different from the glass formation p. In all cases, the density, enthalpy, and entropy would change until the glasses become metastable liquids at a fixed p, thus qualitatively relating κ to variation in these properties.

  8. Effects of ionization on silicate glasses. [Silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Primak, W.

    1982-02-01

    This evaluation of radiation effects in silicate glasses caused by ionization is based on our own investigations, on material collected in our files (reports, articles, and notes), and on a computer literature search through recent issues of Physics Abstracts and Chemical Abstracts (and the apparently pertinent references which appeared). Some of our recent results, available heretofore only in internal correspondence, are presented in some detail. It is concluded that research into the behavior of silicate glasses generally will be required before the specific effects in the radioactive waste storage glasses can be properly understood and evaluated. Two particular neglected areas of investigation are targeted for immediate concern: a kinetic analysis of annealing data and the acquisition of data on effects of irradiation at controlled elevated temperatures.

  9. Refractories Quality Improvement for Glass Industry Upgrading

    Institute of Scientific and Technical Information of China (English)

    ZENG Dafan

    2009-01-01

    @@ 1 Glass Industry and Refractories Industry Closely Connect 1.1 Glass Development Drives Refractories Progress Refractories are indispensable to glass industry; the rapid development of glass industry drives the growth of refractories industry. China's glass industry developed slowly before the mid 1980s. The kilns and furnaces were backward and small-scale with furnace life of only 2-3 years; glass was produced with extremely low efficiency and poor quality. During that period, refractories for glass melting furnaces had very limited varieties and inferior quality. The fused cast refractories for advanced glass melting furnaces were imported, for the materials made in China could not meet the requirements, which seriously restrained the technical progress of China's glass industry.

  10. Antibacterial effects of glass ionomers.

    Science.gov (United States)

    DeSchepper, E J; White, R R; von der Lehr, W

    1989-04-01

    Glass ionomer cements have been shown to possess antimicrobial activity. Proposed mechanisms of action include acidity and fluoride. It was the purpose of this study to determine the antimicrobial effect of 11 glass ionomer cements, their individual powder and liquid components and one resin-bonded liner containing high fluoride ionomer glass against Streptococcus mutans #6715. The role of fluoride and pH in the antibacterial activity was also studied. Using agar diffusion assay methodology, the following results were obtained. All of the glass ionomer cements were inhibitory against S. mutans. The antibacterial cements and slurries that were tested for fluoride, released the ion in excess of reported minimum inhibitory values. The antimicrobial activity of the liquid components, that were tested for the effects of pH changes, was totally lost when the pH was adjusted to 5. The resin bonded liner was inactive against S. mutans and did not release inhibitory concentrations of fluoride. These results indicate that freshly-mixed glass ionomer cements are antimicrobial against S. mutans and that the mechanism of action is probably a function of both fluoride and pH although additional factors may be involved.

  11. Kinetic competition during glass formation

    Energy Technology Data Exchange (ETDEWEB)

    Perepezko, J.H., E-mail: perepezk@engr.wisc.edu [University of Wisconsin-Madison, Department of Materials Science and Engineering, 1509 University Ave., Madison, WI 53706 (United States); Santhaweesuk, C.; Wang, J.Q. [University of Wisconsin-Madison, Department of Materials Science and Engineering, 1509 University Ave., Madison, WI 53706 (United States); Imhoff, S.D. [Los Alamos National Laboratory, Materials Science and Technology Div., Los Alamos, NM 87545 (United States)

    2014-12-05

    Highlights: • The kinetics of glass formation has been elucidated in an Fe and Au-base alloy. • A critical cooling rate range should be considered for glass formation. • Wedge casting, calorimetry and upquenching data are used to model TTT curves. - Abstract: For vitrification of an alloy melt during cooling there is a kinetic competition with the nucleation and growth of metastable and stable crystalline phases. Many of the measures of glass forming ability (GFA) attempt to capture some of the features of the kinetic competition, but the GFA metrics are static measures and the kinetic processes are dynamic in nature. In fact, the critical cooling rate for glass formation should be viewed in terms of a critical cooling rate range to acknowledge the stochastic nature of crystal nucleation behavior. Direct measurements of the critical cooling rate range confirm this behavior and also provide useful input for kinetics analysis. Usually kinetics analyses are based upon crystallization behavior that is measured either isothermally or upon heating to temperatures near the crystallization onset, T{sub x} and the results are extrapolated to much higher temperatures. This practice is based upon a number of assumptions about transport behavior in the undercooled liquid. With rapid up-quenching of amorphous samples, the high temperature crystallization behavior can be measured and used to refine the kinetics analysis and provide useful insight on the kinetic competition and glass forming ability.

  12. Electrical conduction and glass relaxation in alkali- silicate glasses

    Science.gov (United States)

    Angel, Paul William

    Electrical response measurements from 1 Hz to 1 MHz between 50o and 540oC were made on potassium, sodium and lithium-silicate glasses with low alkali oxide contents. Conductivity and electrical relaxation responses for both annealed and air quenched glasses of the same composition were compared. Quenching was found to lower the dc conductivity, σdc, and activation energy as well as increase the pre-exponential term when compared to the corresponding annealed glass of the same composition. All of the glasses exhibited Arrhenius behavior in the log σdc against 1/T plots. A sharp decrease in σdc was observed for glasses containing alkali concentrations of 7 mol% or less. The σdc activation energy exhibited similar behavior when plotted as a function of alkali composition and was explained in terms of a mixture of the weak and strong electrolyte models. The depression angle for fits to the complex impedance data were also measured as a function of thermal history, alkali concentration and alkali species. These results were interpreted in terms of changes in the distribution of relaxation times. Annealed samples from a single melt of a 10 mol% K2O-90SiO2 glass were reheated to temperatures ranging from 450o to 800oC, held isothermally for 20 min, and then quenched in either air or silicon oil. The complex impedance of both an annealed and the quenched samples were then measured as a function of temperature from 120o to 250oC. The σdc was found to be remain unaffected by heat treatments below 450oC, to increase rapidly over an approximate 200oC range of temperatures that was dependent on cooling rate and to be constant for heat treatments above this range. This behavior is interpreted in terms of the mean structural relaxation time as a function of temperature and cooling rate near the glass transition temperature and glass transformation ranges. A more detailed definition for the transition and transformation temperatures and ranges was also provided.

  13. HLW Glass Studies: Development of Crystal-Tolerant HLW Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Matyas, Josef; Huckleberry, Adam R.; Rodriguez, Carmen P.; Lang, Jesse B.; Owen, Antionette T.; Kruger, Albert A.

    2012-04-02

    In our study, a series of lab-scale crucible tests were performed on designed glasses of different compositions to further investigate and simulate the effect of Cr, Ni, Fe, Al, Li, and RuO2 on the accumulation rate of spinel crystals in the glass discharge riser of the HLW melter. The experimental data were used to expand the compositional region covered by an empirical model developed previously (Matyáš et al. 2010b), improving its predictive performance. We also investigated the mechanism for agglomeration of particles and impact of agglomerates on accumulation rate. In addition, the TL was measured as a function of temperature and composition.

  14. Fabrication and characterization of 20 nm planar nanofluidic channels by glass-glass and glass-silicon bonding.

    Science.gov (United States)

    Mao, Pan; Han, Jongyoon

    2005-08-01

    We have characterized glass-glass and glass-Si bonding processes for the fabrication of wide, shallow nanofluidic channels with depths down to the nanometer scale. Nanochannels on glass or Si substrate are formed by reactive ion etching or a wet etching process, and are sealed with another flat substrate either by glass-glass fusion bonding (550 degrees C) or an anodic bonding process. We demonstrate that glass-glass nanofluidic channels as shallow as 25 nm with low aspect ratio of 0.0005 (depth to width) can be achieved with the developed glass-glass bonding technique. We also find that silicon-glass nanofluidic channels, as shallow as 20 nm with aspect ratio of 0.004, can be reliably obtained with the anodic bonding technique. The thickness uniformity of sealed nanofluidic channels is confirmed by cross-sectional SEM analysis after bonding. It is shown that there is no significant change in the depth of the nanofluidic channels due to anodic bonding and glass-glass fusion bonding processes.

  15. In situ effects of restorative materials on dental biofilm and enamel demineralisation.

    Science.gov (United States)

    Sousa, R P; Zanin, I C J; Lima, J P M; Vasconcelos, S M L C; Melo, M A S; Beltrão, H C P; Rodrigues, L K A

    2009-01-01

    Since secondary caries is one of the main reasons for replacing restorations, this study assessed the effects of different restorative materials on the microbiological composition of dental biofilm and on enamel demineralisation around the restoration. A randomized, double-blind, split-mouth in situ design was conducted in one phase of 14 days, during which, 20 volunteers wore palatal devices containing five human dental enamel slabs. Each slab was randomly restored with one of the following materials: Filtek-Z-250/Single Bond, control group (composite resin), Permite (amalgam), Fuji II (encapsulated resin-modified glass ionomer), Vitremer (resin-modified glass ionomer) and Ketac Molar (conventional glass ionomer). The volunteers used fluoride dentifrice, 3x/day and a 20% sucrose solution was dripped onto the slabs 8x/day. The biofilm formed on the slabs was analyzed to determine the counts of total streptococci, mutans streptococci and lactobacilli. Enamel demineralisation was determined by cross-sectional microhardness (CSMH) at 20 and 70 microm from the margin of the restoration. Kruskal-Wallis and analysis of variance, followed by least mean squares (LMS) test, were used to evaluate microbiota and CSMH among the groups. The significance level used was 5%. No statistically significant differences were found in the cariogenic microbiota grown on the slabs. At a 20-mum distance, only Fuji II statistically differed from the other groups, showing the lowest demineralisation. At 70 microm, Fuji II significantly inhibited demineralisation when compared to Permite, Filtek-Z-250 and Ketac Molar. In the context of fluoride dentifrice and under the cariogenic exposure conditions of this study, only the encapsulated resin-modified glass ionomer material provided additional protection against secondary caries.

  16. INFLUENCE OF GLASS CULLET IN CEMENT PASTES

    Institute of Scientific and Technical Information of China (English)

    A.Karamberi; E.Chaniotakis; D.Papageorgiou; A.Moutsatsou

    2006-01-01

    The present study investigates glass and cement compatibility with a view to use glass as a cement replacement. Amber, flint and green glasses were chosen due to their prevalence in the Greek market as packaging materials. The factors under investigation were the pozzolanicity of the glass cullet, the hydration rate and the mechanical strength development of the cement pastes, as well as the expansion of the specimens due to alkali-silica reaction.Moreover, the potential enhancement of glass pozzolanic activity was examined. The results of the study were encouraging to show the potentiality of utilising glass cullet in cementitious products.

  17. High density fluoride glass calorimeter

    Science.gov (United States)

    Xie, Q.; Scheltzbaum, J.; Akgun, U.

    2014-04-01

    The unprecedented radiation levels in current Large Hadron Collider runs, and plans to even increase the luminosity creates a need for new detector technologies to be investigated. Quartz plates to replace the plastic scintillators in current LHC calorimeters have been proposed in recent reports. Quartz based Cherenkov calorimeters can solve the radiation damage problem, however light production and transfer have proven to be challenging. This report summarizes the results from a computational study on the performance of a high-density glass calorimeter. High-density, scintillating, fluoride glass, CHG3, was used as the active material. This glass has been developed specifically for hadron collider experiments, and is known for fast response time, in addition to high light yield. Here, the details of a Geant4 model for a sampling calorimeter prototype with 20 layers, and its hadronic as well as electromagnetic performances are reported.

  18. Phase transitions and glass transition in a hyperquenched silica–alumina glass

    DEFF Research Database (Denmark)

    Zhang, Y.F.; Zhao, D.H.; Yue, Yuanzheng

    2017-01-01

    We investigate phase transitions, glass transition, and dynamic behavior in the hyperquenched 69SiO2–31Al2O3 (mol%) glass (SA glass). Upon reheating, the SA glass exhibits a series of thermal responses. Subsequent to the sub-Tg enthalpy release, the glass undergoes a large jump in isobaric heat...... capacity (ΔCp) during glass transition, implying the fragile nature of the SA glass. The mullite starts to form before the end of glass transition, indicating that the SA glass is extremely unstable against crystallization. After the mullite formation, the remaining glass phase exhibits an increased Tg...... and a suppressed ΔCp. The formation of cristobalite at 1553 K indicates the dominance of silica in the remaining glass matrix. The cristobalite gradually re-melts as the isothermal heat-treatment temperature is raised from 1823 to 1853 K, which is well below the melting point of cristobalite, while the amount...

  19. Temprature Sponses of Intelligence Glass

    Institute of Scientific and Technical Information of China (English)

    Li Baojun; Liu Ming; Yang Tao; Fu Li; Zhou Yao; Li Tiansi

    2004-01-01

    The windowpane is an important collecting sunlight part of building, and also a part that loses most heat.How to increase absorbing heat and decrease losing heat of the windowpane is the key problem of the construction saving energy technology. The intelligence glass can auto control transmissivity with varying temperature outside the room.When temperature outside the room is above 25 ℃, the transmissivity of the windowpane is decreased with increasing of temperature outside the room. The composition of the intelligence glass and its temperature varying cove with outside the room on the basis of testing result for the windowpane were introduced.

  20. Plate shell structures of glass

    DEFF Research Database (Denmark)

    Bagger, Anne

    to their curved shape. A plate shell structure maintains a high stiffness-to-weight ratio, while facilitating the use of plane structural elements. The study focuses on using laminated glass panes for the load bearing facets. Various methods of generating a plate shell geometry are suggested. Together with Ghent......, such as facet size, imperfections, and connection characteristics. The critical load is compared to that of a similar, but smoothly curved, shell structure. Based on the investigations throughout the study, a set of guidelines for the structural design of plate shells of glass is proposed....

  1. Characteristics of radiophotoluminescent glass dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Masashi; Shiraishi, Akemi; Murakami, Hiroyuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-07-01

    In Japan Atomic Energy Research Institute, a film badge is recently replaced by a new type radiophotoluminescent (RPL) glass dosimeter for external personal monitoring. Some fundamental characteristics of this dosimeter, such as dose dependence linearity, energy dependence, angular dependence, dose evaluation accuracy at mixed irradiation conditions, fading, etc., were examined at the Facility of Radiation Standard (FRS), JAERI. The results have proved that the RPL glass dosimeter has sufficient characteristics for practical use as a personal dosimeter for all of the items examined. (author)

  2. Experimental studies of glass refining

    Science.gov (United States)

    Subramanian, R. S.; Cole, R.; Kondos, P.

    1984-01-01

    The basic components of the experimental apparatus were selected and acquired. Techniques were developed for the fabrication of the special crucibles necessary for the experiments. Arrangements were made for the analysis of glass and gas bubble samples for composition information. Donations of major equipment were received for this project from Owens, Illinois where a similar study had been conducted a few year ago. Decisions were made regarding the actual glass composition to be used, the gas to be used in the first experiments, and the temperatures at which the experiments should be conducted. A microcomputer was acquired, and work was begun on interfacing the video analyzer to it.

  3. Aneesur Rahman Prize for Computational Physics Talk: Numerical Simulations of Spin Glasses and Related Systems

    Science.gov (United States)

    Young, A. Peter

    2009-03-01

    Systems with disorder and ``frustration'' occur in many branches of science. There has been considerable effort to understand one such type of system, known as the ``spin glass'', because it can be probed in fine detail experimentally by applying a magnetic field, and because it can be modeled by simple-looking Hamiltonians which are amenable to numerical simulation. Analytical work is very difficult and has been carried out mainly on models with unphysical features such as infinite-range interactions. Hence, much of what we know about spin glasses and related systems comes from numerical simulations on simplified models. In this talk I will describe some of the difficulties in performing reliable spin glass simulations. Then I will discuss several questions concerning phase transitions in spin glasses and related systems that have been addressed by simulations in recent years including (i) whether there is universality, (ii) whether there is a ``vortex glass'' transition in a disordered type-II superconductor in a magnetic field, (iii) whether ``chiralities'' play a crucial role in Heisenberg spin glasses, and (iv) whether there is a line of transitions (AT line) in a magnetic field.

  4. Physical stability of drugs after storage above and below the glass transition temperature: Relationship to glass-forming ability.

    Science.gov (United States)

    Alhalaweh, Amjad; Alzghoul, Ahmad; Mahlin, Denny; Bergström, Christel A S

    2015-11-10

    Amorphous materials are inherently unstable and tend to crystallize upon storage. In this study, we investigated the extent to which the physical stability and inherent crystallization tendency of drugs are related to their glass-forming ability (GFA), the glass transition temperature (Tg) and thermodynamic factors. Differential scanning calorimetry was used to produce the amorphous state of 52 drugs [18 compounds crystallized upon heating (Class II) and 34 remained in the amorphous state (Class III)] and to perform in situ storage for the amorphous material for 12h at temperatures 20°C above or below the Tg. A computational model based on the support vector machine (SVM) algorithm was developed to predict the structure-property relationships. All drugs maintained their Class when stored at 20°C below the Tg. Fourteen of the Class II compounds crystallized when stored above the Tg whereas all except one of the Class III compounds remained amorphous. These results were only related to the glass-forming ability and no relationship to e.g. thermodynamic factors was found. The experimental data were used for computational modeling and a classification model was developed that correctly predicted the physical stability above the Tg. The use of a large dataset revealed that molecular features related to aromaticity and π-π interactions reduce the inherent physical stability of amorphous drugs.

  5. Structures and optical properties of tellurite glasses and glass ceramics

    Science.gov (United States)

    Hart, Robert Theodore, Jr.

    The structures and optical properties of (K2O)15(Nb 2O5)15(TeO2)70 glass and glass ceramic have been studied in order to understand the second harmonic generation observed from the glass ceramic. We have used 93Nb NMR, Raman spectroscopy, differential scanning calorimetry, small angle x-ray scattering, transmission electron microscopy, and powder x-ray and neutron scattering. We find that there is a microstructure consistent with binodal phase separation leading to spherical inclusions ˜20 nm in size. Upon heat treatment, these domains become nanocrystals of K2Te 4O9. A theory of optical heterogeneity is used to describe the observed second harmonic generation which is ˜95 times more intense that quartz. The chi(2) value for this material is 3.0 x 10-9 esu. A second project has used 125Te and 17O NMR to study alkali tellurite glasses in the system (M2O) x(TeO2)10-x, where M = Li, Na or K and x = 1, 2 or 3. The 125Te results show that complex models of network modification are needed to explain the resulting spectra that include a distribution of polyhedral tellurite units at all compositions. The 17O results show that there is a clear distinction between bridging and non-bridging oxygen sites in tellurite crystals and that sophisticated NMR experiments should be able to distinguish them in the glasses. Further, we have used Extended Huckel theory tight-binding calculations to predict the 17O NMR shifts of SiO2, GeO 2 and TeO2. We find that these calculations allow accurate predictions of the chemical shifts based solely on the trend in valence orbital size, and that expensive calculations of electron currents need not be used for this application.

  6. Recycling of post-consumer glass: energy savings, CO2 emission reduction, effects on glass quality and glass melting

    NARCIS (Netherlands)

    Beerkens, R.G.C.; Kers, G.; Santen, E. van

    2011-01-01

    This presentation shows the advantages of re-melting post-consumer glass, but also the potential risks of using contaminated cullet in the raw material batch of glass furnaces (e.g. container glass furnaces). As an example of potential advantages: increasing the cullet % in the batch of an efficient

  7. Recycling of post-consumer glass: energy savings, CO2 emission reduction, effects on glass quality and glass melting

    NARCIS (Netherlands)

    Beerkens, R.G.C.; Kers, G.; Santen, E. van

    2011-01-01

    This presentation shows the advantages of re-melting post-consumer glass, but also the potential risks of using contaminated cullet in the raw material batch of glass furnaces (e.g. container glass furnaces). As an example of potential advantages: increasing the cullet % in the batch of an efficient

  8. A comparison study on the microleakage of glass-ionomer cements of teeth by confocal laser scanning microscope and metallurgical microscope%牙体玻璃离子充填材料边缘微渗漏的激光扫描共聚焦显微镜与金相显微镜比较研究

    Institute of Scientific and Technical Information of China (English)

    包广洁; 李子夏; 康宏

    2011-01-01

    目的:在两种不同显微镜下定量观测人离体牙充填玻璃离子水门汀后边缘微渗漏的情况,并对两种方法进行比较.方法:选取新鲜无龋前磨牙,备洞,充填玻璃离子水门汀,37℃水浴条件下分别置于0.1%罗丹明B荧光染料或1%甲基蓝溶液浸染,激光扫描共聚焦显微镜和金相显微镜下分别测量染液渗入深度,定量评价微渗漏程度,对两种方法的检测结果进行比较.结果:两种方法均能检测到染液渗漏,在分别充填传统型玻璃离子水门汀和树脂改性玻璃离子水门汀的情况下,金相显微镜下测得的渗漏值分别为(33.18±5.59)μm和(32.30±3.76)μm,与激光扫描共聚焦显微镜下所得渗漏深度(22.57±2.59)μm及(21.93±1.51)μm相比,差异有显著统计学意义(P<0.05).结论:激光扫描共聚焦显微镜和金相显微镜均可用于牙体充填材料边缘微渗漏的观测,但综合效果前者更优.%Objective: To evaluate and compare two kinds of microscopes used to measure the microleakage of glass-ionomer cements in isolated human teeth. Methods: Extracted caries-free premolars were selected and the standard class I cavities were prepared on occlusal surface of the teeth and filled with glass-ionomer cements ( group Al and B1 ) and resin-modified glass-ionomer cements ( group A2 and B2 ) respectively. The samples were kept in 0. 1% rhodamine-B solution or 1% methylene blue at 37 ℃ for 24 hours.Confocal laser scanning microscope( CLSM ) or metallurgical microscope were used to visualize the depths of dye penetrated pathways and quantitate the depth of penetration respectively. Results :The dye penetrations existed in all of the groups. The microleakage depths of observed by CLSM (22.57 ±:2. 59)μm and (21.93 ± 1. 51 ) μm were resulted in less marginal microleakage than metallurgical microscope (33.18 ±5.59) μm and (32. 30 ±3.76) μm, P <0. 05. The microleakage depths measured under CLSM and metallugical microscope

  9. Sustainable Innovation of Glass Design and Craft

    DEFF Research Database (Denmark)

    Sparre-Petersen, Maria

    2014-01-01

    Barely any research has been made into the implementation of sustainable principles in glass design and craft. A common tendency among students and practitioners is to consider it problematic if not impossible to develop a “truly sustainable practice”. Generally glass crafts people and glass...... innovation within the creative practices of glass design and craft. The paper will consist of an exploration of how introduction of sustainable principles may serve as a catalyst for aesthetic innovation in a process of experimentation with materials end techniques. A workshop for students of glass...... at The Royal Danish Academy of Fine Arts, School of Design, Bornholm, where new glass was replaced with recycled glass will provide the empirical foundation for a discussion and analysis of the issue. Background For more than 5000 years glass has been utilized by humans in numerous ways ranging from spacecraft...

  10. Packaging glass with hierarchically nanostructured surface

    KAUST Repository

    He, Jr-Hau

    2017-08-03

    An optical device includes an active region and packaging glass located on top of the active region. A top surface of the packaging glass includes hierarchical nanostructures comprised of honeycombed nanowalls (HNWs) and nanorod (NR) structures extending from the HNWs.

  11. The appraisal of structural glass assemblies

    CERN Document Server

    Overend, M

    2002-01-01

    A design methodology is advanced primarily to determine the tensile strength of annealed and tempered glass. The proposed approach consists of an analytical method to assess the tensile strength of glass, sigma sub f , and a computer algorithm which is used to compute the applied equivalent uniform stress, sigma sub p. The glass design approach put forward endeavours to ensure that the surface tensile strength of glass is not exceeded by the equivalent uniform stress. The analytical method, referred to as the General Crack Growth Model, is related to the fundamental properties of the glass surface and incorporates all factors that are known to significantly affect the strength of glass. The General Crack Growth Model is based on the comparison of recent fracture mechanics methods and empirical formulations proposed elsewhere. The proposed glass strength equation or the derived glass strength charts may be used to determine the maximum allowable surface tension, sigma sub f. The performance of the proposed Gen...

  12. Chalcogenide Glass for Passive Infrared Applications

    Institute of Scientific and Technical Information of China (English)

    Xianghua Zhang; Hongli Ma; Jacques Lucas

    2003-01-01

    Chalcogenide glass fibers have been successfully used for remote spectroscopy, temperature sensing and CO2 laser power delivery. In bulk form, chalcogenide glass is the most promising candidate for replacing the expensive germanium lenses for thermal imaging.

  13. Flight Deck I-Glasses Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Flight Deck i-Glasses is a color, stereoscopic 3-D display mounted on consumer style eye glass frames that will enhance operator performance and multi-modal...

  14. Energy-Efficient Glass Melting: Submerged Combustion

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-01-01

    Oxy-gas-fired submerged combustion melter offers simpler, improved performance. For the last 100 years, the domestic glass industry has used the same basic equipment for melting glass on an industrial scale.

  15. A new method to detect the vortex glass phase and its evidence in YBCO.

    Science.gov (United States)

    Adesso, M G; Polichetti, M; Pace, S

    2008-09-24

    The evidence of the vortex glass phase has been obtained by analysing the nonlinear magnetic response of type-II superconductors. The method introduced here is based on a combined frequency dependence analysis of the real and imaginary part of the 1st and 3rd harmonics of the AC magnetic susceptibility. The analysis has been performed by taking into account both the components and the Cole-Cole plots (i.e. the imaginary part as a function of the real part). Numerical simulations have been used to identify the fingerprints of the magnetic behaviour in the vortex glass phase. These characteristics allowed the vortex glass phase to be distinguished from the other disordered phases, even those showing similar electrical properties. Finally, this method has been successfully applied to detecting the vortex glass phase in an YBCO bulk melt-textured sample.

  16. The Gardner Transition: A new approach for understanding low-temperature glasses

    Science.gov (United States)

    Charbonneau, Patrick

    Recent theoretical advances in the mean-field theory of glasses predict the existence deep in the glass phase of a novel phase transition, a so-called Gardner transition. This transition signals the emergence of a complex free energy landscape composed of a marginally stable hierarchy of sub-basins within a broad glass metabasin. It is thus the onset of marked changes in thermal and transport properties of glasses, and ultimately leads to the unusual critical behavior at jamming. The Gardner transition itself is immediately related to a diverging (i) characteristic relaxation time, (ii) caging susceptibility and (iii) correlation length of the caging heterogeneity as well as aging, even in well-thermalized glasses. We have detected some of these signatures both in a mean-field model and in standard hard-sphere glass formers. We find the results to quantitatively agree with theory in the former and qualitatively so in the latter, which suggest that the transition should be detectable in a wide array of numerical and experimental systems. Interestingly, although the Gardner transitions is primarily associated with structural glass formers, we also find features of the transition in crystals of polydisperse particles once the landscape becomes rough.

  17. First-order study of property/composition relationships for Hanford Waste Vitrification Plant glasses

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, G.F.; Hrma, P.R.; Bates, S.O.; Schweiger, M.J.; Smith, D.E.

    1993-01-01

    A first-order composition variability study (CVS-I) was conducted for the Hanford Waste Vitrification Plant (HWVP) program to preliminarily characterize the effects on key glass properties of variations i selected glass (waste and frit) components. The components selected were Si0{sub 2},B{sub 2}O{sub 3},A1{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, ZrO{sub 2}, Na{sub 2}O,Li{sub 2}O,CaO,MgO, and Others (all remaining waste components). A glass composition region was selected for study based on the expected range of glass compositions and the results of a previous series of scoping and solubility studies. Then, a 23-glass statistically-designed mixture experiment was conducted and data obtained for viscosity, electrical conductivity, glass transition temperature, thermal expansion, crystallinity, and durability [Materials Characterization Center (MCC-1) 28-day leach test and the 7-day Product Consistency Test (PCT)]. These data were modeled using first-order functions of composition, and the models were used to investigate the effects of the components on glass and melt properties. The CVS-I data and models will also be used to support the second-order composition variability study (CVS-II).

  18. First-order study of property/composition relationships for Hanford Waste Vitrification Plant glasses

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, G.F.; Hrma, P.R.; Bates, S.O.; Schweiger, M.J.; Smith, D.E.

    1993-01-01

    A first-order composition variability study (CVS-I) was conducted for the Hanford Waste Vitrification Plant (HWVP) program to preliminarily characterize the effects on key glass properties of variations i selected glass (waste and frit) components. The components selected were Si0[sub 2],B[sub 2]O[sub 3],A1[sub 2]O[sub 3], Fe[sub 2]O[sub 3], ZrO[sub 2], Na[sub 2]O,Li[sub 2]O,CaO,MgO, and Others (all remaining waste components). A glass composition region was selected for study based on the expected range of glass compositions and the results of a previous series of scoping and solubility studies. Then, a 23-glass statistically-designed mixture experiment was conducted and data obtained for viscosity, electrical conductivity, glass transition temperature, thermal expansion, crystallinity, and durability [Materials Characterization Center (MCC-1) 28-day leach test and the 7-day Product Consistency Test (PCT)]. These data were modeled using first-order functions of composition, and the models were used to investigate the effects of the components on glass and melt properties. The CVS-I data and models will also be used to support the second-order composition variability study (CVS-II).

  19. GLASS: The Grism Lens-Amplified Survey From Space. HST Grism Spectroscopy of the Frontier Fields

    Science.gov (United States)

    Schmidt, Kasper B.; Schmidt

    The Grism Lens-Amplified Survey From Space (GLASS) is a 140 orbit spectroscopic survey of 10 massive galaxy clusters, including the six Hubble Frontier Fields. GLASS has observed the cluster cores with the HST-WFC3 G102 and G141 grisms providing a wide wavelength coverage in the near-infrared from roughly 0.8-1.7μm. The parallel fields were observed through the optical ACS G800L grism. Taking advantage of the lensing magnification of the clusters, GLASS reaches intrinsic spectroscopic 1σ flux limits of roughly 10-18erg/s/cm2 and improved spatial resolution for lensed sources behind the clusters. These features are particularly useful for the three main science drivers of GLASS which are, I) exploring the universe at the epoch of reionization, II) describe how metals cycle in and out of galaxies, and III) asses the environmental dependence of galaxy evolution. The former two benefit highly from the improved depth and increased resolution provided by the cluster lensing. Apart from the main science drivers, a slew of ancillary science has been enabled by the survey, including improving cluster lens modeling and searches for supernovae. Here we present the survey and the GLASS data releases, which are continuously being made available to the community through https://archive.stsci.edu/prepds/glass/. For further information we refer to Schmidt et al. (2014), Treu et al. (2015), and http://glass.physics.ucsb.edu.

  20. Embedded adhesive connection for laminated glass plates

    DEFF Research Database (Denmark)

    Hansen, Jens Zangenberg; Poulsen, S.H.; Bagger, A.

    2012-01-01

    The structural behavior of a new connection design, the embedded adhesive connection, used for laminated glass plates is investigated. The connection consists of an aluminum plate encapsulated in-between two adjacent triple layered laminated glass plates. Fastening between glass and aluminum...... usage in a design situation. The embedded connection shows promising potential as a future fastening system for load-carrying laminated glass plates....

  1. Volcanic glasses, their origins and alteration processes

    Science.gov (United States)

    Friedman, I.; Long, W.

    1984-01-01

    Natural glass can be formed by volcanic processes, lightning (fulgarites) burning coal, and by meteorite impact. By far the most common process is volcanic - basically the glass is rapidly chilled molten rock. All natural glasses are thermodynamically unstable and tend to alter chemically or to crystallize. The rate of these processes is determined by the chemical composition of the magma. The hot and fluid basaltic melts have a structure that allows for rapid crystal growth, and seldom forms glass selvages greater than a few centimeters thick, even when the melt is rapidly cooled by extrusion in the deep sea. In contrast the cooler and very viscous rhyolitic magmas can yield bodies of glass that are tens of meters thick. These highly polymerized magmas have a high silica content - often 71-77% SiO2. Their high viscosity inhibits diffusive crystal growth. Basalt glass in sea water forms an alteration zone called palagonite whose thickness increases linearly with time. The rate of diffusion of water into rhyolitic glass, which follows the relationship - thickness = k (time) 1 2, has been determined as a function of the glass composition and temperature. Increased SiO2 increases the rate, whereas increased CaO, MgO and H2O decrease the rate. The activation energy of water diffusion varies from about 19 to 22 kcal/mol. for the glasses studied. The diffusion of alkali out of rhyolite glass occurs simultaneously with water diffusion into the glass. The rate of devitrification of rhyolitic glass is a function of the glass viscosity, which in turn is a function of water content and temperature. Although all of the aforementioned processes tend to destroy natural glasses, the slow rates of these processes, particularly for rhyolitic glass, has allowed samples of glass to persist for 60 million years. ?? 1984.

  2. Fluoride glasses: properties, technology and applications

    OpenAIRE

    Poulain, M.

    2010-01-01

    Heavy Metal Fluoride Glasses (HMFG) make a group of specialty glasses that require a dry processing, purity control of starting materials and specific thermal procedures. Numerous glass compositions have been identified in different chemical systems: fluorozirconates, fluoroaluminates and fluoroindates. The most commonly used HMFG is the ZBLAN fluorozirconate glass that exhibits the largest stability against devitrification. By comparison to ZBLAN the IR cut-off wavelength is shorter in AlF3-...

  3. Optical scattering in glass ceramics

    NARCIS (Netherlands)

    Mattarelli, M.; Montagna, M.; Verrocchio, P.

    2008-01-01

    The transparency of glass ceramics with nanocrystals is generally higher than that expected from the theory of Rayleigh scattering. We attribute this ultra-transparency to the spatial correlation of the nanoparticles. The structure factor is calculated for a simple model system, the random sequentia

  4. Printing Silver Nanogrids on Glass

    Science.gov (United States)

    Sanders, Wesley C.; Valcarce, Ron; Iles, Peter; Smith, James S.; Glass, Gabe; Gomez, Jesus; Johnson, Glen; Johnston, Dan; Morham, Maclaine; Befus, Elliot; Oz, Aimee; Tomaraei, Mohammad

    2017-01-01

    This manuscript describes a laboratory experiment that provides students with an opportunity to create conductive silver nanogrids using polymeric templates. A microcontact-printed polyvinylpyrrolidone grid directs the citrate-induced reduction of silver ions for the fabrication of silver nanogrids on glass substrates. In addition to…

  5. Reflectivity of metallodielectric photonic glasses

    NARCIS (Netherlands)

    Velikov, K.; Vos, W.L.; Moroz, A.; van Blaaderen, A.

    2004-01-01

    We report on the fabrication and optical properties of metallodielectric photonic glasses of colloidal silver spheres with a radius ranging from 200 to 420 nm and volume fractions around 60%. Strong modulations (∼25%) in the optical reflectivity were observed in the visible range for these structure

  6. Reflectivity of metallodielectric photonic glasses

    NARCIS (Netherlands)

    Velikov, K.P.; Vos, W.L.; Moroz, A.; Blaaderen, van A.

    2004-01-01

    We report on the fabrication and optical properties of metallodielectric photonic glasses of colloidal silver spheres with a radius ranging from 200 to 420 nm and volume fractions around 60%. Strong modulations (~25%) in the optical reflectivity were observed in the visible range for these structure

  7. Passing through the Glass Ceiling.

    Science.gov (United States)

    McGinty, Robert L.

    This paper describes personal and professional networking, discusses data on women and networking skills, and argues that women should exercise these skills in their efforts to shatter the "glass ceiling" and achieve their career potential. An introductory discussion notes that women, though they do network, may develop ties primarily with other…

  8. Spin glasses and neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Parga, N. (Comision Nacional de Energia Atomica, San Carlos de Bariloche (Argentina). Centro Atomico Bariloche; Universidad Nacional de Cuyo, San Carlos de Bariloche (Argentina). Inst. Balseiro)

    1989-07-01

    The mean-field theory of spin glass models has been used as a prototype of systems with frustration and disorder. One of the most interesting related systems are models of associative memories. In these lectures we review the main concepts developed to solve the Sherrington-Kirkpatrick model and its application to neural networks. (orig.).

  9. Penetration Physics of Armor Glass

    Science.gov (United States)

    2009-11-30

    Penetration Response of Borosilicate Glass during Short Rod Impact”, Proc. 23rd Int. Symp. Ballistics, 2, 1251-1258, Graficas Couche, Madrid, Spain (2007...glass”, Proc. 23rd Int. Symp. Ballistics, 2, 1049-1056, Graficas Couche, Madrid, Spain (2007). 8D. R. Curran, “Comparison of Mesomechanical and

  10. Hollow glass for insulating layers

    Science.gov (United States)

    Merticaru, Andreea R.; Moagar-Poladian, Gabriel

    1999-03-01

    Common porous materials, some of which will be considered in the chapters of this book, include concrete, paper, ceramics, clays, porous semiconductors, chromotography materials, and natural materials like coral, bone, sponges, rocks and shells. Porous materials can also be reactive, such as in charcoal gasification, acid rock dissolution, catalyst deactivation and concrete. This study continues the investigations about the properties of, so-called, hollow glass. In this paper is presented a computer simulation approach in which the thermo-mechanical behavior of a 3D microstructure is directly computed. In this paper a computer modeling approach of porous glass is presented. One way to test the accuracy of the reconstructed microstructures is to computed their physical properties and compare to experimental measurement on equivalent systems. In this view, we imagine a new type of porous type of glass designed as buffer layer in multilayered printed boards in ICs. Our glass is a variable material with a variable pore size and surface area. The porosity could be tailored early from the deposition phases that permitting us to keep in a reasonable balance the dielectric constant and thermal conductivity.

  11. Are the dynamics of silicate glasses and glass-forming liquids embedded in their elastic properties?

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Mauro, John C.

    According to the elastic theory of the glass transition, the dynamics of glasses and glass-forming liquids are controlled by the evolution of shear modulus. In particular, the elastic shoving model expresses dynamics in terms of an activation energy required to shove aside the surrounding atoms, ...... of the silicate glass transition are governed by additional factors beyond the evolution of the shear modulus....

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

    NARCIS (Netherlands)

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

    2008-01-01

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

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

    NARCIS (Netherlands)

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

    2008-01-01

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

  14. Phosphate-based glasses: Prediction of acoustical properties

    Energy Technology Data Exchange (ETDEWEB)

    El-Moneim, Amin Abd, E-mail: aminabdelmoneim@hotmail.com

    2016-04-15

    In this work, a comprehensive study has been carried out to predict the composition dependence of bulk modulus and ultrasonic attenuation coefficient in the phosphate-based glass systems PbO-P{sub 2}O{sub 5}, Li{sub 2}O-TeO{sub 2}-B{sub 2}O{sub 3}-P{sub 2}O{sub 5}, TiO{sub 2}-Na{sub 2}O-CaO-P{sub 2}O{sub 5} and Cr{sub 2}O{sub 3}-doped Na{sub 2}O-ZnO-P{sub 2}O{sub 5} at room temperature. The prediction is based on (i) Makishima-Mackenzie theory, which correlates the bulk modulus with packing density and dissociation energy per unit volume, and (ii) Our recently presented semi-empirical formulas, which correlate the ultrasonic attenuation coefficient with the oxygen density, mean atomic ring size, first-order stretching force constant and experimental bulk modulus. Results revealed that our recently presented semi-empirical formulas can be applied successfully to predict changes of ultrasonic attenuation coefficient in binary PbO-P{sub 2}O{sub 5} glasses at 10 MHz frequency and in quaternary Li{sub 2}O-TeO{sub 2}-B{sub 2}O{sub 3}-P{sub 2}O{sub 5}, TiO{sub 2}-Na{sub 2}O-CaO-P{sub 2}O{sub 5} and Cr{sub 2}O{sub 3}-Na{sub 2}O-ZnO-P{sub 2}O{sub 5} glasses at 5 MHz frequency. Also, Makishima-Mackenzie theory appears to be valid for the studied glasses if the effect of the basic structural units that present in the glass network is taken into account.

  15. Jagged Edges of the Glass Ceiling

    Science.gov (United States)

    Robinson, Victoria L.

    2004-01-01

    Although many aspiring young women might believe the glass ceiling was shattered a decade ago, they still need to understand how that glass ceiling impacted an older generation of women in educational leadership. They also must be aware that some segments of the glass ceiling might still exist. This article provides a historical overview of the…

  16. Advances in glass-ionomer cements

    OpenAIRE

    Davidson, Carel Leon

    2006-01-01

    This article describes the properties, advances and shortcomings of glass-ionomer cement as a restorative material. The adhesion of glass-ionomer to tooth structure is less technique sensitive than composite resins and its quality increases with time. Therefore glass-ionomer might turn out to the more reliable restorative material in minimal invasive dentistry based on adhesive techniques.

  17. Optical limiting in semiconductor-doped glasses

    Science.gov (United States)

    Bindra, K. S.; Oak, S. M.; Rustagi, K. C.

    1996-02-01

    We report optical limiting at 527 nm in two Schott semiconductor-doped glasses OG530 and OG515. These two glasses show quite contrasting nonlinear optical behaviour. The glass OG515 shows strong clamping while OG530 shows no clamping in optical limiting inspite of having much larger nonlinear refractive index. Similarly OG530 exhibits saturation of absorption while OG515 does not.

  18. Advances in glass-ionomer cements.

    Science.gov (United States)

    Davidson, Carel Leon

    2006-01-01

    This article describes the properties, advances and shortcomings of glass-ionomer cement as a restorative material. The adhesion of glass-ionomer to tooth structure is less technique sensitive than composite resins and its quality increases with time. Therefore glass-ionomer might turn out to the more reliable restorative material in minimal invasive dentistry based on adhesive techniques.

  19. Jagged Edges of the Glass Ceiling

    Science.gov (United States)

    Robinson, Victoria L.

    2004-01-01

    Although many aspiring young women might believe the glass ceiling was shattered a decade ago, they still need to understand how that glass ceiling impacted an older generation of women in educational leadership. They also must be aware that some segments of the glass ceiling might still exist. This article provides a historical overview of the…

  20. Simulation of Glass Fiber Forming Processes

    DEFF Research Database (Denmark)

    Von der Ohe, Renate

    Two glass fiber forming processes have been simulated using FEM, which are the drawing of continuous glass fibers for reinforcement purposes and the spinning of discontinuous glass fibers - stone wool for insulation. The aim of this work was to set up a numerical model for each process, and to use...

  1. 24th International Congress on Glass

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    April 7-11,2016Shanghai,ChinaWelcome The International Commission on Glass was created in 1933 in order to promote international collaboration and to disseminate information throughout the entire glass community.One way to achieve this mission consists in the triennial organization of the International Glass Congress.

  2. Protection of window glass from acoustic leakage

    OpenAIRE

    Lych, Sergij; Rakobovchuk, Volodymyr

    2013-01-01

    In a survey was presented an analysis of the most common glass samples on the Ukrainian market on their protection level against leakage of acoustic information. The glass samples were studied by means of roentgen analysis, and the impact of elemental composition of glass according to a laser beam reflection factor was defined.

  3. DURABLE GLASS FOR THOUSANDS OF YEARS

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C.

    2009-12-04

    The durability of natural glasses on geological time scales and ancient glasses for thousands of years is well documented. The necessity to predict the durability of high level nuclear waste (HLW) glasses on extended time scales has led to various thermodynamic and kinetic approaches. Advances in the measurement of medium range order (MRO) in glasses has led to the understanding that the molecular structure of a glass, and thus the glass composition, controls the glass durability by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. During the early stages of glass dissolution, a 'gel' layer resembling a membrane forms through which ions exchange between the glass and the leachant. The hydrated gel layer exhibits acid/base properties which are manifested as the pH dependence of the thickness and nature of the gel layer. The gel layer ages into clay or zeolite minerals by Ostwald ripening. Zeolite mineral assemblages (higher pH and Al{sup 3+} rich glasses) may cause the dissolution rate to increase which is undesirable for long-term performance of glass in the environment. Thermodynamic and structural approaches to the prediction of glass durability are compared versus Ostwald ripening.

  4. Reductive spectrophotometry of divalent tin sensitization on soda lime glass

    Science.gov (United States)

    Bejugam, Vinith; Wei, Xingfei; Roper, D. Keith

    2016-07-01

    Rapid and facile evaluation of tin (II) sensitization could lead to improved understanding of metal deposition in electroless (EL) plating. This report used a balanced redox reaction between 3,3‧,5,5‧-tetramethylbenzidine dihydrochloride (TMB-HCL) and N-bromosuccinimide (NBS) to evaluate effects of sensitization conditions (i.e., sensitization time, analyte concentration, aqueous immersion, and acid content) on the accumulated mass of surface-associated divalent tin ion. The accumulated mass of tin (II) increased as the sensitization time increased up to 30 s in proportion to aqueous tin (II) chloride concentrations between 2.6 and 26 mM at a trifluoroacetic acid (TFA) content of 68 mM. The average mass peaked at 7.3 nanomoles (nmol) per cm2 after a 5 s aqueous immersion post-sensitization, and then decreased with increasing aqueous immersion post-sensitization. The total average tin (II) + tin (IV) accumulated on soda lime glass measured by inductively coupled plasma optical emission spectrometry (ICP-OES) was 17% higher at 30 s sensitization, suggesting a fraction of the tin (II) present may have oxidized to tin (IV). These results indicated that in situ spectrophotometric evaluation of tin (II) could support development of EL plating for electronics, catalysis, and solar cells.

  5. Chiral-glass transition and replica symmetry breaking of a three-dimensional heisenberg spin glass

    Science.gov (United States)

    Hukushima; Kawamura

    2000-02-01

    Extensive equilibrium Monte Carlo simulations are performed for a three-dimensional Heisenberg spin glass with the nearest-neighbor Gaussian coupling to investigate its spin-glass and chiral-glass orderings. The occurrence of a finite-temperature chiral-glass transition without the conventional spin-glass order is established. Critical exponents characterizing the transition are different from those of the standard Ising spin glass. The calculated overlap distribution suggests the appearance of a peculiar type of replica-symmetry breaking in the chiral-glass ordered state.

  6. Analysis of early medieval glass beads - Glass in the transition period

    Science.gov (United States)

    Šmit, Žiga; Knific, Timotej; Jezeršek, David; Istenič, Janka

    2012-05-01

    Glass beads from graves excavated in Slovenia and dated archaeologically to the 7th-10th century AD were analysed by the combined PIXE-PIGE method. The results indicate two groups of glass; natron glass made in the Roman tradition and glass made with alkalis from the ash of halophytic plants, which gradually replaced natron glass after c. 800 AD. The alkalis used in the second group of glass seem to be in close relation to a variant of the Venetian white glass that appeared several centuries later. The origin of this glass may be traced to glass production in Mesopotamia and around the Aral Sea. All the mosaic beads with eye decoration, as well as most of the drawn-segmented and drawn-cut beads analysed, are of plant-ash glass, which confirms their supposed oriental origin.

  7. Analysis of early medieval glass beads - Glass in the transition period

    Energy Technology Data Exchange (ETDEWEB)

    Smit, Ziga, E-mail: ziga.smit@ijs.si [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana (Slovenia); Jozef Stefan Institute, Jamova 39, P.O.B. 3000, SI-1001 Ljubljana (Slovenia); Knific, Timotej [National Museum of Slovenia, Presernova 20, SI-1000 Ljubljana (Slovenia); Jezersek, David [Jozef Stefan Institute, Jamova 39, P.O.B. 3000, SI-1001 Ljubljana (Slovenia); Istenic, Janka [National Museum of Slovenia, Presernova 20, SI-1000 Ljubljana (Slovenia)

    2012-05-01

    Glass beads from graves excavated in Slovenia and dated archaeologically to the 7th-10th century AD were analysed by the combined PIXE-PIGE method. The results indicate two groups of glass; natron glass made in the Roman tradition and glass made with alkalis from the ash of halophytic plants, which gradually replaced natron glass after c. 800 AD. The alkalis used in the second group of glass seem to be in close relation to a variant of the Venetian white glass that appeared several centuries later. The origin of this glass may be traced to glass production in Mesopotamia and around the Aral Sea. All the mosaic beads with eye decoration, as well as most of the drawn-segmented and drawn-cut beads analysed, are of plant-ash glass, which confirms their supposed oriental origin.

  8. The role of glass composition in the behaviour of glass acetic acid and glass lactic acid cements.

    Science.gov (United States)

    Shahid, Saroash; Billington, R W; Pearson, G J

    2008-02-01

    Cements have recently been described, made from glass ionomer glass reacted with acetic and lactic acid instead of polymeric carboxylic acid. From their behaviour a theory relating to a possible secondary setting mechanism of glass ionomer has been adduced. However, only one glass (G338) was used throughout. In this study a much simpler glass ionomer glass (MP4) was compared with G338. This produced very different results. With acetic acid G338 formed cement which became resistant to water over a period of hours, as previously reported, MP4 formed cement which was never stable to water. With lactic acid G338 behaved similarly to G338 with acetic acid, again as reported, but MP4 produced a cement which was completely resistant to water at early exposure and unusually became slightly less resistant if exposure was delayed for 6 h or more. These findings indicate that the theories relating to secondary setting in glass ionomer maturation may need revision.

  9. Effective Utilisation of Waste Glass in Concrete

    Directory of Open Access Journals (Sweden)

    Sameer Shaikh

    2015-12-01

    Full Text Available Glass is a widely used product throughout the world; it is versatile, durable and reliable. The uses of glass ranges drastically, therefore waste glass is discarded, stockpiled or land filled. About million tons of waste glass is generated and around large percent of this glass is disposed of in landfills. This pattern has influenced environmental organizations to pressure the professional community to lower the amount of glass being discarded as well as find use to the non-recycled glass in new applications. In relation, the recycling of waste glass as a component in concrete gives waste glass a sustainable alternative to land filling and therefore makes it economically viable.The proposed study of utilising waste glass powder(GLP in concrete as partial replacement of cement as well as the use of crushed glass particles(CGP retained on 1.18mm & 2.36mm IS sieve as a partial replacement to sand, which offers important benefits related to strength of concrete as well as it is eco-friendly. Recycling of mixed-colour waste glass possesses major problems for municipalities, and this problem can be greatly eliminated by re-using waste glass as sand/cement replacement in concrete. Moreover, re-using waste materials in construction can reduce the demand on the sources of primary materials.In this project the attempts have been made to partially replace the cement as well as sand by waste glass powder and crushed glass particles with equal combination by 5% interval up to 20% replacement and observe its effect on the strength of concrete after 7 days and 28 days of curing.

  10. Aging in chalcohalide glasses: Origin and consequences

    DEFF Research Database (Denmark)

    Jensen, Martin; Smedskjær, Morten Mattrup; Wang, W.

    2012-01-01

    The application of chalcogenide and chalcohalide glasses is limited by their uncontrolled drift in properties over time due to aging processes. In the present work, we perform aging experiments on some chalcohalide glasses in oxidizing, inert and reducing atmospheres and afterwards we measure...... the elemental concentration depth profiles in the surface layer of the glasses by using secondary neutral mass spectroscopy. The results show that anionic diffusion processes occur in the glasses during aging. The aging process leads to a decrease in microhardness of the studied glasses, which is attributed...... to both physical aging (i.e., structural relaxation) and chemical aging (i.e., compositional change of the surface layer)....

  11. Major element composition of Luna 20 glasses.

    Science.gov (United States)

    Warner, J.; Reid, A. M.; Ridley, W. I.; Brown, R. W.

    1972-01-01

    Ten per cent of the 50 to 150-micron size fraction of Luna 20 soil is glass. A random suite of 270 of these glasses has been analyzed by electron microprobe techniques. The major glass type forms a strong cluster around a mean value corresponding to Highland basalt (anorthositic gabbro) with 70% normative feldspar. Minor glass groups have the compositions of mare basalts and of low-K Fra Mauro type basalts. The glass data indicate that Highland basalt is the major rock type in the highlands north of Mare Fecunditatis.

  12. A study on the radiopacity of cavity lining materials for posterior composite resin restoration

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Joo Hoon [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Chosun University, Kwangju (Korea, Republic of); Choi, Eui Hwan [Dept. of Conservative Dentistry, College of Dentistry, Chosun University, Kwangju (Korea, Republic of)

    2000-12-15

    The aim of this study was to determine the relative radiopacities of cavity lining materials (Resin-modified Glass Ionomer cement, Compomer and Flowable resin) for posterior composite resin restoration. Resin-modified glass ionomer cement (Fuji II LC, Vitrebond (TM)), Compomers (Dyract , Compoglass, F2000, Dyract(R) flow Compoglass Flow) and Flowable resins (Tetric (R) flow, Aeliteflo (TM) Revolution (TM)) were used. Five specimens of 5 mm in diameter and 2 mm thick were fabricated with each material. Human molars were horizontally sectioned 2 mm thick to include both enamel and dentin. The radiopacities of enamel, dentin, cavity lining materials, aluminum step wedge were obtained from conventional radiograph and NIH image program. All the tested lining materials showed levels of radiopacity the same as or greater than that of dentin. All compomer tested (Dyract (R), Compoglass, F2000, Dyract (R) flow, Compoglass Flow) and Vitrebond (TM), Tetric (R) flow were more radiopaque than enamel. The radiopacities of Fuji II LC and Revolution (TM) were between enamel and dentin and resin-modified glass ionomer cement, Compomer and Tetric (R) flow were greater than those of Revolution (TM), Aeliteflo (TM) or dentin. The level of radiopacity of the tested materials was variable; those with low radiopacity should be avoided in class II restorations, where a clear determination of recurrent caries by the examining clinician could be compromised. Clinician should be able to distinguish these cavity lining materials radiographically from recurrent decay, voids, gaps, or other defects that lead to clinical failure. Utilization of materials ranked more radiopaque than enamel would enable clinicians to distinguish the lining material from tooth structure.

  13. Optical Properties of Li2B4O7 Glasses Doped with Rare-Earths and Transition Metal Ions

    Science.gov (United States)

    2001-01-01

    K.P. O’Donnell, B. Henderson and D. Hollis, " Disorder and the optical spectroscopy of Cr 3+- doped glasses: II. Glasses with high and low ligand...ions in oxide compounds", Fiz. Tw. Tela, 31(1), pp. 243-249, 1989. 11. W. Chen, J.O. Maim, V. Zwiller, Y. Huang, S. Liu, R. Wallenberg , J.O. Bovin and L

  14. Bioactive Glasses in Dentistry: A Review

    Directory of Open Access Journals (Sweden)

    Abbasi Z

    2015-03-01

    Full Text Available Bioactive glasses are silicate-based and can form a strong chemical bond with the tissues. These biomaterials are highly biocompatible and can form a hydroxyapatite layer when implanted in the body or soaked in the simulated body fluid. Due to several disadvantages, conventional glass processing method including melting of glass components, is replaced by sol-gel method with a large number of benefits such as low processing temperature, higher purity and homogeneity and therefore better control of bioactivity. Bioactive glasses have a wide range of applications, particularly in dentistry. These glasses can be used as particulates or monolithic shapes and porous or dense constructs in different applications such as remineralization or hypersensitivity treatment. Some properties of bioactive glasses such as antibacterial properties can be promoted by adding different elements into the glass. Bioactive glasses can also be used to modify different biocompatible materials that need to be bioactive. This study reviews the significant developments of bioactive glasses in clinical application, especially dentistry. Furthermore, we will discuss the field of bioactive glasses from beginning to the current developments, which includes processing methods, applications, and properties of these glasses.

  15. Identifying glass compositions in fly ash

    Directory of Open Access Journals (Sweden)

    Katherine eAughenbaugh

    2016-01-01

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

  16. Symmetry foundations of a polymer model for close-packed metallic liquids and glasses

    Science.gov (United States)

    Kraposhin, V. S.; Talis, A. L.

    2016-02-01

    The atomic packing density of metallic melts and glasses is too high for their structures to be considered as chaotic. To remove this contradiction, we propose to describe the structures of metallic liquids and the glasses that form from them using (i) a base set of three spirals made of regular tetrahedra with specific noncrystallographic symmetry and (ii) combinatorial permutations of the vertices of a set of the coordination polyhedra that describe the polymorphic transformations in metals. The symmetry base of the proposed model of the structures of liquids and glasses is represented by projective linear groups PSL(2, p), where the order of the Galois field is p = 3, 7, and 11. These groups uniquely determine a tetrahedron, the 7-vertex joining of four tetrahedra along their faces (tetrablock), the 11-vertex joining of two tetrablocks into a spiral, and the throwing over of the diagonals in a rhombus from two triangular faces of neighboring tetrahedra. The throwing over of the diagonals in a rhombus is considered as a unit act of any structural transformation and ensures the melt-crystal, melt-glass, and glass-crystal transitions and the structural relaxation of metallic glasses. In terms of the proposed scheme, the high density of melts and glasses is caused by tetrahedral packing (up to 78%), and the absence of a diffraction pattern of melts and glasses is explained by the absence of translation along the spiral axis. The suggested polymer model also explains the collective effects (string vibrations) that were detected upon measuring the shear modulus relaxation of a metallic glass.

  17. Durability of Silicate Glasses: An Historical Approach

    Energy Technology Data Exchange (ETDEWEB)

    Farges, Francois; /Museum Natl. Hist. Natur. /Stanford U., Geo. Environ. Sci.; Etcheverry, Marie-Pierre; /Marne la Vallee U.; Haddi, Amine; /Marne la Valle U.; Trocellier,; /Saclay; Curti, Enzo; /PSI, Villigen; Brown, Gordon E., Jr.; /SLAC, SSRL

    2007-01-02

    We present a short review of current theories of glass weathering, including glass dissolution, and hydrolysis of nuclear waste glasses, and leaching of historical glasses from an XAFS perspective. The results of various laboratory leaching experiments at different timescales (30 days to 12 years) are compared with results for historical glasses that were weathered by atmospheric gases and soil waters over 500 to 3000 years. Good agreement is found between laboratory experiments and slowly leached historical glasses, with a strong enrichment of metals at the water/gel interface. Depending on the nature of the transition elements originally dissolved in the melt, increasing elemental distributions are expected to increase with time for a given glass durability context.

  18. Durability of Silicate Glasses: An Historical Approach

    Energy Technology Data Exchange (ETDEWEB)

    Farges, Francois; /Museum Natl. Hist. Natur. /Stanford U., Geo. Environ. Sci.; Etcheverry, Marie-Pierre; /Marne la Vallee U.; Haddi, Amine; /Marne la Valle U.; Trocellier,; /Saclay; Curti, Enzo; /PSI, Villigen; Brown, Gordon E., Jr.; /SLAC, SSRL

    2007-01-02

    We present a short review of current theories of glass weathering, including glass dissolution, and hydrolysis of nuclear waste glasses, and leaching of historical glasses from an XAFS perspective. The results of various laboratory leaching experiments at different timescales (30 days to 12 years) are compared with results for historical glasses that were weathered by atmospheric gases and soil waters over 500 to 3000 years. Good agreement is found between laboratory experiments and slowly leached historical glasses, with a strong enrichment of metals at the water/gel interface. Depending on the nature of the transition elements originally dissolved in the melt, increasing elemental distributions are expected to increase with time for a given glass durability context.

  19. Designing and constructing corrugated glass facades

    Directory of Open Access Journals (Sweden)

    Rob Nijsse

    2015-05-01

    Full Text Available Flat glass panels are in use since the time of the Roman Empire. In the ruins of the city of Pompeii, destroyed by the Vulcan Vesuvius in 79 DC, a glass panel in a bronze frame of 300 × 600 mm was found. In this article we describe a mayor improvement in the structural behaviour of glass panels by making the glass curved, or more accurately, corrugated. Both the in- and out-plane loading meet far more resistance against deformation, and the corrugated glass panels have a largely increased bearing capacity with the same thickness of glass the flat panel has. Also architecturally the appearance of a corrugated glass panel in facades is far more appealing.

  20. Recirculation bubbler for glass melter apparatus

    Science.gov (United States)

    Guerrero, Hector; Bickford, Dennis

    2007-06-05

    A gas bubbler device provides enhanced recirculation of molten glass within a glass melter apparatus. The bubbler device includes a tube member disposed within a pool of molten glass contained in the melter. The tube member includes a lower opening through which the molten glass enters and upper slots disposed close to (above or below) the upper surface of the pool of molten glass and from which the glass exits. A gas (air) line is disposed within the tube member and extends longitudinally thereof. A gas bubble distribution device, which is located adjacent to the lower end of the tube member and is connected to the lower end of the gas line, releases gas through openings therein so as to produce gas bubbles of a desired size in the molten glass and in a distributed pattern across the tube member.

  1. Structural relaxation in annealed hyperquenched basaltic glasses

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, John C.; Potuzak, M.

    2012-01-01

    The enthalpy relaxation behavior of hyperquenched (HQ) and annealed hyperquenched (AHQ) basaltic glass is investigated through calorimetric measurements. The results reveal a common onset temperature of the glass transition for all the HQ and AHQ glasses under study, indicating that the primary r...... relaxation is activated at the same temperature regardless of the initial departure from equilibrium. The analysis of secondary relaxation at different annealing temperatures provides insights into the enthalpy recovery of HQ glasses.......The enthalpy relaxation behavior of hyperquenched (HQ) and annealed hyperquenched (AHQ) basaltic glass is investigated through calorimetric measurements. The results reveal a common onset temperature of the glass transition for all the HQ and AHQ glasses under study, indicating that the primary...

  2. An investigation of iron phosphate glasses

    Science.gov (United States)

    Fang, Xiangyu

    The effect of melting history on the iron redox equilibrium, structure, crystallization and properties of a binary iron phosphate glass with a 40Fe 2O3-60P2O5, mol%, batch composition were investigated. The structure and properties of single and mixed alkali iron phosphate glasses were also studied. Mossbauer, Raman and infrared spectroscopy were used to determine the changes in the concentration of iron ions and phosphate units in the structure. Differential thermal analysis, X-ray diffraction and thermogravimetric analysis were used to investigate crystallization. Density, molar volume, thermal expansion, dc electrical conductivity and dielectric constant and loss tangent were measured. The heat capacity and glass transition behavior of the glasses was also measured by the differential scanning calorimeter method. The effect of the melting temperature is stronger than the melting time on the concentration of Fe2+ ions in iron phosphate glasses. The pyrophosphate network in iron phosphate glasses and their general properties do not change either with melting temperature and time or with adding up to 20 mol% of single and mixed alkali oxides. The dissolution rate (in deionized water) of these glasses is generally very low (˜10-9 g/cm2/min) and nearly independent of the relative concentration of Fe 2+ or Fe3+ ions. The dissolution rate of the iron phosphate glasses containing 20 mol% of single or mixed alkali oxide can be comparable to that of window glass. There is no mixed alkali effect in the iron phosphate glasses. The crystallization tendency indicates that the glass structure becomes closer to that of crystalline Fe3(P2O 7)2 with increasing concentration of Fe2+ ions in the glass. The large fragility parameters indicates that the iron phosphate glasses belong in the category of the fragile glass-forming liquids.

  3. Glass shell manufacturing in space

    Science.gov (United States)

    Nolen, R. L.; Downs, R. L.; Ebner, M. A.

    1982-01-01

    Highly-uniform, hollow glass spheres, which are used for inertial-confinement fusion targets, are formed from metal-organic gel powder feedstock in a drop-tower furnace. The modelling of this gel-to-sphere transformation has consisted of three phases: gel thermochemistry, furnance-to-gel heat transfer, and gravity-driven degradation of the concentricity of the molten shell. The heat transfer from the furnace to the free-falling gel particle was modelled with forced convection. The gel mass, dimensions, and specific heat as well as furnace temperature profile and furnace gas conductivity, were controlled variables. This model has been experimentally verified. In the third phase, a mathematical model was developed to describe the gravity-driven degradation of concentricity in molten glass shells.

  4. Sodium diffusion in boroaluminosilicate glasses

    DEFF Research Database (Denmark)

    Smedskjaer, Morten M.; Zheng, Qiuju; Mauro, John C.

    2011-01-01

    of isothermal sodium diffusion in BAS glasses by ion exchange, inward diffusion, and tracer diffusion experiments. By varying the [SiO2]/[Al2O3] ratio of the glasses, different structural regimes of sodium behavior are accessed. We show that the mobility of the sodium ions decreases with increasing [SiO2]/[Al2O......3] ratio, revealing that sodium is more mobile when it acts as a charge compensator to stabilize network formers than when it acts as a creator of non-bridging oxygens on tetrahedrally-coordinated silicon and trigonal boron. The impacts of both the addition of iron and its redox state on the sodium...... be attributed to the fact that for sodium inward diffusion, the charge compensation for electron holes is a rather slow process that limits the rate of diffusion. (C) 2011 Elsevier B.V. All rights reserved....

  5. Google Glass in Medical Applications

    OpenAIRE

    2015-01-01

    Le thème de ce travail de Bachelor est de réalisé une application pour les Google Glass pour le domaine médical et plus précisément pour les ambulanciers. Le but est de pouvoir filmer les interventions des ambulanciers et de transmettre en temps réel la vidéo à l’hôpital, l’ambulancier peut communiquer directement avec le personnel médical à l’hôpital et le personnel médical peut aussi envoyer les informations lié au patient et d’afficher sur les Google Glass. Pour atteindre ce but, il faut c...

  6. Formulation of heat absorbing glasses

    Directory of Open Access Journals (Sweden)

    Álvarez-Casariego, Pedro

    1996-06-01

    Full Text Available In the thermal exchanges between buildings and environment, glazing is an element of major importance, for it largely influences the so-called Solar Heat Gain and Thermal Losses. These parameters can be modified by applying different type of coatings onto glass surface or by adding colorant compounds during glass melting. The latter is a cheaper way to control the Solar Heat Gain. The knowledge of the laws governing the interaction between colorant compounds and solar radiation, allows us to define glass formulations achieving specific aesthetic requirements and solar energy absorption. In this paper two examples of application of the modelling of glass colorants spectral absorptance are presented. First is addressed to obtaining a glass with high luminous transmittance and low solar energy transmittance, and the other one to obtaining a glass with neutral colour appearance and minimized solar energy transmittance. Calculation formulas are defined together with photometric properties so-obtained. These type of glasses are particularly suitable to be used as building and automotive glazing, for they retain the mechanical characteristics and possibilities of transformation of standard glass.

    En los intercambios de energía entre un edificio y el medio exterior, el vidrio es el elemento de mayor importancia, por su influencia en la Ganancia de Calor Solar y en las Pérdidas Térmicas. Estos parámetros pueden ser modificados mediante el depósito de capas sobre el vidrio o mediante la adición de compuestos absorbentes de la radiación solar. Esta última vía es la más económica para controlar la Ganancia de Calor Solar. El conocimiento de las leyes que gobiernan la interacción de los diversos colorantes con la radiación solar, permite definir formulaciones de vidrios con características especificas de tipo estético y de absorción energética. En este trabajo se presentan dos ejemplos de aplicación de esta modelización de las

  7. Properties of unidirectional GFRPs based on an epoxy resin modified with polysulphone or an epoxyurethane oligomer

    Science.gov (United States)

    Solodilov, V. I.; Gorbatkina, Yu. A.

    2006-11-01

    The mechanical properties of unidirectional GFRPs based on an ED-22 epoxy resin were investigated. The resin was modified with a PSK-1 polysulphone or a PEF-3a epoxyurethane oligomer. Triethanolaminotitanate or diaminodiphenilsulphone was used as a hardener. The modification did not improve the mechanical properties of GFRPs in quasi-static loading; but in a low-speed impact loading, the shear strength of epoxypolysulphone GFRPs with 20 wt.% PSK-1 increased by 20-25%. For all the GFRPs investigated, the shear strength grew linearly with the logarithm of loading rate. The introduction of the modifiers increased the fracture toughness considerably: by 100 and 70% for GFRPs modified with 20 wt.% PSK-1 and 50 wt.% PEF-3a, respectively.

  8. Cyanate Ester Resin Modified with Nano-particles for Inclusion in Continuous Fiber Reinforced Composites

    Science.gov (United States)

    2011-02-25

    have higher viscosities. Figure 1.1 shows the correlation between the cured state Tg and the temperature at which the uncured thermoset prepolymer has... prepolymers continuing to decrease with increasing temperature. The result is that at virtually all processing temperatures, the BECy system has

  9. STUDIES ON EPOXY RESINS MODIFIED WITH POLY (BUTYLENE TEREPHTHALATE)-b-POLY (TETRAMETHYLENE GLYCOL)

    Institute of Scientific and Technical Information of China (English)

    WANG Xia; ZHAO Binyi; LI Zhengyi; YU Yunzhao

    1997-01-01

    Poly(butylene terephthalate)-b-poly(tetramethylene glycol) (PBT-b-PTMG) was used as rheology modifier for the epoxy resin. The segmental copolymer formed spherulites in the epoxy medium. This copolymer was very effective in endowing yield stresses to the liquid resin. The PTMG segment brought in a lowering of the dissolution temperature of the spherulites in the epoxy gel. The cured resin with PBT-b-PTMG as modifier was twophase materials. The rheology modifier improved the mechanical properties of the cured resin as well. The flexible PTMG segments, however, were not in favour of the toughening effect of the modifier. This was attributed to the large domain size of the dispersed phase.

  10. Interface and properties of epoxy resin modified by elastomeric nano-particles

    Institute of Scientific and Technical Information of China (English)

    HUANG Fan; LIU Yiqun; ZHANG Xiaohong; GAO Jianming; SONG Zhihai; TANG Banghui; WEI Genshuan; QIAO Jinliang

    2005-01-01

    Study on a new composite of epoxy resin/elastomeric nano-particles (ENP) is reported in this paper, which shows that, in comparison with pure epoxy resin and epoxy toughened with CTBN, the composites of epoxy resin/carboxylic nitrile-butadiene ENP and epoxy resin/styrene butadiene vinyl-pyridine ENP possess both higher toughness and heat resistance. Both ENPs used in the study have an average size of less than 100 nm. Study on the epoxy network's morphology and interface properties suggests that due to the chemical reaction between ENP and epoxy resin and more hydrogen bonds between nitrile groups of the rubber and hydroxyl groups of the epoxy resin, stronger interaction at the larger interface may lead to the observed excellent properties of the epoxy resin toughened with ENP.

  11. Study on the microstructure evolution of phenol-formaldehyde resin modified by ceramic additive

    Institute of Scientific and Technical Information of China (English)

    JIANG Haiyun; WANG Jigang; DUAN Zhichao; LI Fan

    2007-01-01

    Boron carbide (B4C) was selected as the additive for the modification of a phenol-formaldehyde (PF) resin, and the micro-structural evolution of the modified resin at high temperature was investigated.Results showed that the distribution of B4C particles became uniform at elevated temperatures.The primary oxidation of B4C started to occur at 450℃,and lots of B2O3 was formed above 650℃.By the modification reactions of B,C,the volatiles including CO was converted into amorphous carbon and remained in the resin matrix,which was responsible for maintaining the stability of the resin at high temperatures.

  12. Kinetic studies of the polymerization of an epoxy resin modified with rhodamine B

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Raquel; Fernandez d' Arlas, Borja [' Materials - Technologies' Group, Dept. of Chemical and Environmental Engineering, Polytechnic School, Universidad Pais Vasco/Euskal Herriko Unibertsitatea, Pza Europa 1, 20018 Donostia-San Sebastian (Spain); Oyanguren, Patricia A. [INTEMA Univ. Nac. de Mar del Plata-CONICET, JB Justo 4302 Mar del Plata (Argentina); Mondragon, Inaki, E-mail: inaki.mondragon@ehu.es [' Materials - Technologies' Group, Dept. of Chemical and Environmental Engineering, Polytechnic School, Universidad Pais Vasco/Euskal Herriko Unibertsitatea, Pza Europa 1, 20018 Donostia-San Sebastian (Spain)

    2009-09-10

    Novel fluorescent materials were satisfactorily synthesized. With this aim, an epoxy resin based on diglycidyl ether of bisphenol A (DGEBA) was reacted with a laser dye, rhodamine B (RB), to achieve an epoxy-based prepolymer. Then, a diamine, m-xylylenediamine (MXDA), was used as hardener with the purpose of obtaining a crosslinked polymer. The curing conditions strongly influence the intended final properties and the optimization of the curing requires a reliable kinetic model. For that reason, this work presents the kinetic study of the polymerization of the epoxy resin by differential scanning calorimetry (DSC) in isothermal mode as well as by Fourier transform infrared spectroscopy (FTIR). DSC data were fitted using a Kamal autocatalytic equation. Conversion as a function of reaction time curves obtained by means of both techniques agreed well. In addition, the synthesized epoxy-based materials were characterized by proton nuclear magnetic resonance spectroscopy ({sup 1}H NMR) and their fluorescent properties were also analysed.

  13. Pb II

    African Journals Online (AJOL)

    Windows User

    ISSN 1684–5315 ©2012 Academic Journals ... Exposure to Pb above permissible limit (50 ppb in water) .... taken and analyzed for residual metal concentration determination. ..... loss in Pb(II) sorption capacity up to five cycles of reuse of.

  14. Metallic glasses: properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Dugdale, J.S.; Pavuna, D.; Rhodes, P.

    1985-01-01

    Metallic glasses are a class of disordered materials that contrast with crystalline metals and provide a new challenge to theories of electronic structure and magnetic interactions in solids. Their study will undoubtedly broaden and deepen our understanding of the solid state. In addition, they are now finding a wide variety of technological applications. Some of these applications as well as their magnetic properties are presented here. 7 references, 3 figures, 1 table.

  15. Melter Glass Removal and Dismantlement

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, BS

    2000-10-31

    The U.S. Department of Energy (DOE) has been using vitrification processes to convert high-level radioactive waste forms into a stable glass for disposal in waste repositories. Vitrification facilities at the Savannah River Site (SRS) and at the West Valley Demonstration Project (WVDP) are converting liquid high-level waste (HLW) by combining it with a glass-forming media to form a borosilicate glass, which will ensure safe long-term storage. Large, slurry fed melters, which are used for this process, were anticipated to have a finite life (on the order of two to three years) at which time they would have to be replaced using remote methods because of the high radiation fields. In actuality the melters useable life spans have, to date, exceeded original life-span estimates. Initial plans called for the removal of failed melters by placing the melter assembly into a container and storing the assembly in a concrete vault on the vitrification plant site pending size-reduction, segregation, containerization, and shipment to appropriate storage facilities. Separate facilities for the processing of the failed melters currently do not exist. Options for handling these melters include (1) locating a facility to conduct the size-reduction, characterization, and containerization as originally planned; (2) long-term storing or disposing of the complete melter assembly; and (3) attempting to refurbish the melter and to reuse the melter assembly. The focus of this report is to look at methods and issues pertinent to size-reduction and/or melter refurbishment in particular, removing the glass as a part of a refurbishment or to reduce contamination levels (thus allowing for disposal of a greater proportion of the melter as low level waste).

  16. Use of glass ionomers as retrofilling materials.

    Science.gov (United States)

    Barkhordar, R A; Pelzner, R B; Stark, M M

    1989-06-01

    Many materials have been used as retrofillings. Because of the bonding property of glass ionomer cement, this study was conducted to evaluate its possible use as a retrofilling material. Seventy human maxillary anterior teeth were chosen. The root canal systems were cleansed and shaped, and the teeth were assigned to six groups of 10 each. The root canals were obturated with gutta-percha and Grossman sealer, and the apical 2 mm of each root was resected. In all groups a retrofilling preparation was made to a depth of a number 331 bur. The apical preparations were filled in the following manner: silver amalgam (group I), silver amalgam plus two layers of varnish (group II), Ketac-Silver plus two layers of varnish (group III), Ketac-Silver without varnish (group IV), Ketac-Fil plus two layers of varnish (group V), Ketac-Fil without varnish (group VI), and Ketac-Bond (group VII). All the root surfaces with the exception of 2 mm from the resected line were coated with two layers of clear varnish. All the teeth were immersed in methylene blue for 24 hours. After vertical sectioning, dye penetration was measured under a dissecting microscope. The mean apical leakage (in millimeters) was as follows: I = 0.57, II = 0.39, III = 0.22, IV = 0.54, V = 0.11, VI = 0.46, and VII = 0.17. One-way analysis of variance performed on the group means indicated that Ketac-Fil with varnish (group V) and Ketac-Bond (group VII) had significantly less leakage than other groups (p less than 0.05). This study indicates that Ketac-Fil and Ketac-Bond may have potential as retrofilling materials.

  17. High Quantum Efficiency and High Concentration Erbium-Doped Silica Glasses Fabricated by Sintering Nanoporous Glasses

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new method was used to prepare erbium-doped high silica (SiO2%>96%) glasses by sintering nanoporous glasses. The concentration of erbium ions in high silica glasses can be considerably more than that in silica glasses prepared by using conventional methods. The fluorescence of 1532 nm has an FWHM (Full Wave at Half Maximum) of 50 nm, wider than 35 nm of EDSFA (erbium-doped silica fiber amplifer), and hence the glass possesses potential application in broadband fiber amplifiers. The Judd-Ofelt theoretical analysis reflects that the quantum efficiency of this erbium-doped glass is about 0.78, although the erbium concentration in this glass (6×103) is about twenty times higher than that in silica glass. These excellent characteristics of Er-doped high silica glass will be conducive to its usage in optical amplifiers and microchip lasers.

  18. A Modified Glass Formation Criterion for Various Glass Forming Liquids with Higher Reliability

    Institute of Scientific and Technical Information of China (English)

    X.H.Du; J.C.Huang

    2007-01-01

    A modified indicator of the glass forming ability (GFA) from the previous γ= Tx/(Tl+Tg) for various glass forming liquids is proposed based on a conceptual approach which combines more acceptable physical metallurgy views in terms of the time-temperature-transformation diagrams. It is found that the glass forming ability for glass forming liquids is closely associated mainly with two factors, i.e. (2Tx-Tg) and Tl (wherein Tx is the onset crystallization temperature, Tg the glass transition temperature, and Tl the liquidus temperature), and could be predicated by a unified parameter γm defined as (2Tx-Tg)/Tl. This approach is confirmed and validated by experimental data in various glass forming systems including oxide glasses, cryoprotectants and metallic glasses, which all shows a higher reliability when their glass forming ability is predicted by the modified parameter.

  19. Container II

    OpenAIRE

    Baraklianou, Stella

    2016-01-01

    Container II, self-published artists book.\\ud The book was made on the occasion of the artists residency at the Banff Arts Centre, in Alberta Canada. \\ud \\ud Container II is a performative piece, it worked in conjunction with the photographic installation "Stage Set: Cool Tone" . (photographic floor installation, Reclaimed wood, frames, 130x145cm, 2016) \\ud The photographic installation was also part of the artists residency titled "New Materiality" at the Banff Arts Centre. \\ud \\ud Limited E...

  20. The Curious Case of Glass I: High Ionization and Variability of Different Types

    CERN Document Server

    Kruger, Andrew J; Carr, John S; Najita, Joan R; Moerchen, Margaret M; Doppmann, Greg W; Seifahrt, Andreas

    2013-01-01

    Our Spitzer IRS observation of the infrared companion Glass Ib revealed fine structure emission with high ionization ([NeIII]/[NeII]=2.1 and [SIV]/[SIII]=0.6) that indicates the gas is likely illuminated by hard radiation. While models suggest extreme ultraviolet radiation could be present in T Tauri stars (Hollenbach & Gorti 2009 and references therein), this is the first detection of [SIV] and such a high [NeIII]/[NeII] ratio in a young star. We also find that Glass Ib displays the molecules HCN, CO2, and H2O in emission. Here we investigate the Glass I binary system and consider possible mechanisms that may have caused the high ionization, whether from an outflow or disk irradiation. We also model the spectral energy distributions of Glass Ia and Ib to test if the system is a young member of the Chameleon I star-forming region, and consider other possible classifications for the system. We find Glass Ib is highly variable, showing changes in continuum strength and emission features at optical, near-inf...

  1. Additive manufacturing of borosilicate glass (Conference Presentation)

    Science.gov (United States)

    Luo, Junjie; Goldstein, Jonathan T.; Urbas, Augustine M.; Bristow, Douglas A.; Landers, Robert G.; Kinzel, Edward C.

    2017-02-01

    Glasses including have significant scientific and engineering applications including optics, communications, electronics, and hermetic seals. This paper investigates a filament fed process for Additive Manufacturing (AM) of borosilicate glasses. Compared to soda-lime glasses, borosilicate glasses have improved coefficient of thermal expansion (CTE) and are widely used because of thermal shock resistance. In this work, borosilicate glass filaments are fed into a CO2 laser generated melt pool, smoothly depositing material onto the workpiece. Single tracks are printed to explore the effects that different process parameters have on the morphology of printed glass as well as the residual stress trapped in the glass. The transparency of glass allows residual stress to be measured using a polariscope. The effect of the substrate as well and substrate temperature are analyzed. We show that if fracture due to thermal shock can be avoided during deposition, then the residual stress can be relieved with an annealing step, removing birefringence. When combined with progress toward avoiding bubble entrapment in printed glass, we show the AM approach has the potential to produce high quality optically transparent glass for optical applications.

  2. Manufacturing laser glass by continuous melting

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J H; Suratwala, T; krenitsky, S; Takeuchi, K

    2000-07-01

    A novel, continuous melting process is being used to manufacture meter-sized plates of laser glass at a rate 20-times faster, 5-times cheaper, and with 2-3 times better optical quality than with previous one-at-a-time, ''discontinuous'' technology processes. This new technology for manufacturing laser glass, which is arguably the most difficult continuously-melted optical material ever produced, comes as a result of a $60 million, six-year joint R&D program between government and industry. The glasses manufactured by the new continuous melting process are Nd-doped phosphate-based glasses and are marketed under the product names LG-770 (Schott Glass Technologies) and LHG-8 (Hoya Corporation USA). With this advance in glass manufacturing technology, it is now possible to construct high-energy, high-peak-power lasers for use in fusion energy development, national defense, and basic physics research that would have been impractical to build using the old melting technology. The development of continuously melted laser glass required technological advances that have lead to improvements in the manufacture of other optical glass products as well. For example, advances in forming, annealing, and conditioning steps of the laser glass continuous melting process are now being used in manufacture of other large-size optical glasses.

  3. Transfer of glass fragments when bottles and drinking glasses are broken.

    Science.gov (United States)

    Irwin, Margaret

    2011-03-01

    Experiments have been carried out to determine if and how many glass fragments are transferred onto upper garments following breakage of bottles and drinking glasses. In all instances glass was transferred. The numbers of transferred fragments after a bottle is broken ranges from three to twenty five. The numbers of fragments transferred following the breakage of a drinking glass ranges from three to approximately one hundred and twenty. On average three times the amount of glass is transferred following breakage of a drinking glass as compared to breakage of a bottle.

  4. Precise dispersion equations of absorbing filter glasses

    Science.gov (United States)

    Reichel, S.; Biertümpfel, Ralf

    2014-05-01

    The refractive indices versus wavelength of optical transparent glasses are measured at a few wavelengths only. In order to calculate the refractive index at any wavelength, a so-called Sellmeier series is used as an approximation of the wavelength dependent refractive index. Such a Sellmeier representation assumes an absorbing free (= loss less) material. In optical transparent glasses this assumption is valid since the absorption of such transparent glasses is very low. However, optical filter glasses have often a rather high absorbance in certain regions of the spectrum. The exact description of the wavelength dependent function of the refractive index is essential for an optimized design for sophisticated optical applications. Digital cameras use an IR cut filter to ensure good color rendition and image quality. In order to reduce ghost images by reflections and to be nearly angle independent absorbing filter glass is used, e.g. blue glass BG60 from SCHOTT. Nowadays digital cameras improve their performance and so the IR cut filter needs to be improved and thus the accurate knowledge of the refractive index (dispersion) of the used glasses must be known. But absorbing filter glass is not loss less as needed for a Sellmeier representation. In addition it is very difficult to measure it in the absorption region of the filter glass. We have focused a lot of effort on measuring the refractive index at specific wavelength for absorbing filter glass - even in the absorption region. It will be described how to do such a measurement. In addition we estimate the use of a Sellmeier representation for filter glasses. It turns out that in most cases a Sellmeier representation can be used even for absorbing filter glasses. Finally Sellmeier coefficients for the approximation of the refractive index will be given for different filter glasses.

  5. Compositional threshold for nuclear waste glass durability

    Energy Technology Data Exchange (ETDEWEB)

    Farooqi, Rahmatullah; Hrma, Pavel [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of)

    2013-07-01

    The issue of major concern with the waste form, such as glass, is its chemical durability, I. e., the resistance to corrosion by aqueous media. A number of standard durability tests have been established for waste glasses, among which the product consistency test was selected as a criterion of HLW glass acceptability for the repository subsequently, a large PCT database has been collected containing over 1000 glasses. Such a database allows the development of models that relate PCT releases to glass is a strong function of composition, these models are used to formulate acceptable glasses in which the waste loading is maximized. Within the composition space of glasses, a distinct threshold appears to exist that separates 'good' glasses, I. e. these which are sufficiently durable, from 'bad' glasses of a low durability. According to Populate al., transition region between durable and less durable glasses lies around 2a m{sup -2} as determined by the 7-day PCT normalized B release. The objective of our research is to clarify the origin of this threshold by exploring the relationship between glass composition, glass structure and chemical durability around the threshold region. Our study is focused on the corrosion behavior of SiO{sub 2} - B{sub 2}O{sub 3} - Na{sub 2}O - Al{sub 2}O{sub 3} - Colleagues composition region. In particular, we try to identify the durability threshold separating durable from nondurable glasses in the composition space. So far we have explored the elemental releases of Na and B measured with the 7-day PCT.

  6. Formation and 2D-patterning of silver nanoisland film using thermal poling and out-diffusion from glass

    Science.gov (United States)

    Chervinskii, S.; Sevriuk, V.; Reduto, I.; Lipovskii, A.

    2013-12-01

    We fabricated silver nanoisland films and patterned silver nanoisland films using out-diffusion of silver from glass in the course of the ion-exchanged glass substrate annealing in reducing hydrogen atmosphere. The choice of the annealing conditions allows to provide prevailing of silver nanoisland formation over the formation of silver nanoparticles in the bulk of the glass. The procedure of the patterned film formation includes (i) silver-sodium ion exchange in the glass, (ii) thermal poling of the ion-exchanged glass with a profiled anodic electrode, and (iii) annealing the glass in hydrogen. The formation of silver nanoislands in unpoled regions on the glass surface allowed us to avoid any post-processing of very fragile silver island film in formation of 2D-patterned nanoisland structures. Poling of the glass with properly profiled electrode was used for the formation of random chains and ordered arrays of separate silver nanoislands. Depending on processing parameters, a typical island size in the films and chains varied from several to tens of nanometers, and was down to 200 nm in the arrays.

  7. Direct laser writing of a new type of waveguides in silver containing glasses.

    Science.gov (United States)

    Abou Khalil, Alain; Bérubé, Jean-Philippe; Danto, Sylvain; Desmoulin, Jean-Charles; Cardinal, Thierry; Petit, Yannick; Vallée, Réal; Canioni, Lionel

    2017-09-11

    Direct laser writing in glasses is a growing field of research in photonics since it provides a robust and efficient way to directly address 3D material structuring. Generally, direct laser writing in glasses induces physical modifications such as refractive index changes that have been classified under three different types (Type I, II & III). In a silver-containing zinc phosphate glass, direct laser writing additionally proceeds via the formation of silver clusters at the periphery of the interaction voxel. In this paper, we introduce a novel type of refractive index modification based on the creation of the photo-induced silver clusters allowing the inscription of a new type of optical waveguides. Various waveguides as well as a 50-50 beam splitter were written inside bulk glasses and characterized. The waveguiding properties observed in the bulk of such silver-containing glass samples were further transposed to ribbon shaped fibers made of the same material. Our results pave the way for the fabrication of 3D integrated circuits and fiber sensors with original fluorescent, nonlinear optical and plasmonic properties. The universality of these new findings should further extend in any silver-containing glasses that show similar laser-induced behavior in terms of silver cluster production.

  8. Comparative studies of spray pyrolysis deposited copper sulfide nanostructural thin films on glass and FTO coated glass

    Indian Academy of Sciences (India)

    Mehdi Adelifard; Hosein Eshghi; Mohamad Mehdi Bagheri Mohagheghi

    2012-10-01

    CuS thin films with different Cu to S molar ratios (0.33 and 0.43) have been deposited by spray pyrolysis method on glass and FTO coated glass substrates using an aqueous solution of copper (II) acetate and thiourea at a substrate temperature of 285°C. The structural, surface morphological, optical and electrical characterizations of the samples were carried out using XRD, FESEM, UV-Vis and PL spectrophotometer and four-probe apparatus, respectively. X-ray diffraction analysis showed that while the layer/glass sample has an individual CuS (covellite) crystalline phase, the layer/FTO sample includes two additional phases of Cu2S (chalcocite) and Cu1.8S (digenite) as well. Optical measurements showed that all these materials have a relatively high absorption coefficient (∼5 × 104–2.3 × 105 cm-1) in the visible region and direct bandgap of the layers was confirmed with the corresponding room temperature PL spectra. With the resistivity measurements at room and higher temperatures (up to 100°C) confirm that all samples are degenerate in nature with high electrical conductivities of ∼103 (.cm)-1.

  9. Compartive study of microleakage by using four types of luting agents in glass-infiltrated alumina core ceramic%4种粘接剂粘接氧化铝渗透陶瓷基底冠的边缘微渗漏研究

    Institute of Scientific and Technical Information of China (English)

    钱程辉; 钟群; 李国强

    2011-01-01

    目的 研究不同粘接剂对氧化铝渗透陶瓷基底冠微渗漏的影响.方法 选择40个离体磨牙,常规制作氧化铝渗透陶瓷基底冠,随机分为玻璃离子、树脂加强型玻璃离子、树脂粘接剂和自粘接树脂组.在进行微渗漏实验前对样本进行冷热循环.采用染料渗入法测定冠边缘微渗漏情况,进行统计分析.结果 4种粘接剂粘接氧化铝渗透陶瓷基底冠的边缘微渗漏不同,差异有统计学意义(P<0.05),65%的基底冠发生了微渗漏.结论 树脂粘接剂边缘微渗漏少,是粘接氧化铝渗透陶瓷基底冠的理想材料.%Objective To observe and compare the microleakage of glass-infiltrated alumina core ceramic using four types of luting agents.Methods Forty healthy non-carious human molars were selected and randomly assigned to 4groups,10 in each.The glass ionomer, resin-modified glass ionomer, adhesive resin and RelyX Unicem were used for bonding.All specimens were stored in water at 37℃ for 24 hours, then the specimens were subjected to thermocycling 500 times ranging from 5℃ to 55℃.Ten specimens in each group were evaluated by dye penetration.The microleakage was examined with light microscope.Statistical analysis was performed with SPSS 10.0 software package.Results The same kind of glass-infiltrated alumina core ceramic treated with different luting agents demonstrated significantly different degree of microleakage ( P < 0.05 ).Conclusions RelyX Unicem and RelyX ARC were the superior anti-mic-roleakage luting cement, and it is the ideal material for the glass-infiltrated alumina core ceramic.

  10. Interfacial investigation and mechanical properties of glass-Al-glass anodic bonding process

    Science.gov (United States)

    Hu, Lifang; Xue, Yongzhi; Shi, Fangrong

    2017-10-01

    Glass-Al-glass with Al as common anode was successfully bonded together through the anodic bonding process. SEM and EDS were conducted to investigate the interfacial structure of the glass-Al-glass samples. Special attention was given to the element distribution after the bonding process. The element profile of the transitional layer was investigated by glow discharge optical emission microscopy. The results showed that ion migration played an important role during the anodic bonding process, Na+ would precipitate from the back of the glass, and a Na+ depletion region formed at the bonding interface. At the same time, O2‑ diffused into the bonding interface and reacted with the Al, which resulted in a successful bonding process. Furthermore, Al migrated into the glass, which could enhance the bonding process. The peak current of the glass-Al-glass bonding was two times larger than that of the Al-glass bonding, which meant that the glass-Al-glass bonding process could be considered equivalent to two individual Al-glass bonding processes. Tensile strength tests showed that the glass was fractured, and the fractures propagated into the bonding interface, which indicated a reliable bonding process.

  11. Electron anions and the glass transition temperature

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Lewis E.; Sushko, Peter V.; Tomota, Yudai; Hosono, Hideo

    2016-08-24

    Properties of glasses are typically controlled by judicious selection of the glass-forming and glass-modifying constituents. Through an experimental and computational study of the crystalline, molten, and amorphous [Ca12Al14O32]2+ ∙ (e)2, we demonstrate that electron anions in this system behave as glass-modifiers that strongly affect solidification dynamics, the glass transition temperature, and spectroscopic properties of the resultant amorphous material. Concentration of such electron anions is a consequential control parameter: it invokes materials evolution pathways and properties not available in conventional glasses, which opens a new avenue in rational materials design.

  12. Detection of structural heterogeneity of glass melts

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    2004-01-01

    The structural heterogeneity of both supercooled liquid and molten states of silicate has been studied using calorimetric method. The objects of this study are basaltic glasses and liquids. Two experimental approaches are taken to detect the structural heterogeneity of the liquids. One is the hyp......The structural heterogeneity of both supercooled liquid and molten states of silicate has been studied using calorimetric method. The objects of this study are basaltic glasses and liquids. Two experimental approaches are taken to detect the structural heterogeneity of the liquids. One...... is discussed. The ordered structure of glass melts above the liquidus temperature is indirectly characterized by use of X-ray diffraction method. The new approaches are of importance for monitoring the glass melting and forming process and for improving the physical properties of glasses and glass fibers....

  13. Topological Principles of Borosilicate Glass Chemistry

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Mauro, J. C.; Youngman, R. E.

    2011-01-01

    Borosilicate glasses display a rich complexity of chemical behavior depending on the details of their composition and thermal history. Noted for their high chemical durability and thermal shock resistance, borosilicate glasses have found a variety of important uses from common household...... and laboratory glassware to high-tech applications such as liquid crystal displays. In this paper, we investigate the topological principles of borosilicate glass chemistry covering the extremes from pure borate to pure silicate end members. Based on NMR measurements, we present a two-state statistical...... earthborosilicate glasses that enables the accurate prediction of properties such as glass transition temperature, liquid fragility, and hardness. The modeling approach enables an understanding of the microscopic mechanisms governing macroscopic properties. The implications of the glass topology are discussed...

  14. Novel spin glasses by mechanical milling

    Institute of Scientific and Technical Information of China (English)

    周国富; H.Bakker

    1996-01-01

    Novel spin-glass alloys were synthesized by milling intermetallic compounds and also by milling mixtures of crystalline elemental powder in a high-energy ball mill.Spin glass behaviour was found in amorphous Co2Ge,which was amorphised by milling in mechanically disordered crystalline GdAl2 in ball-milled crystalline and amorphous CoZr,and in mechanically alloyed Co-Cu,which formed a supersaturated f.c.c.solid solution.All these materials are binary alloys and tlie concentration of the magnetic element is high,which makes them novel types of spin glasses.It is shown that ball milling may not only lead to structural metallic glasses,but can also generate the magnetic pendant of a structural glass,namely the spin glass.

  15. Woven Glass Fiber Composites with Aligned Carbon Nanotube Sheet Interlayers

    Directory of Open Access Journals (Sweden)

    Hardik Bhanushali

    2016-01-01

    Full Text Available This investigation describes the design, fabrication, and testing of woven glass fiber reinforced epoxy matrix laminates with aligned CNT sheets integrated between plies in order to improve the matrix dominated through thickness properties such as the interlaminar fracture toughness at ply interfaces. Using aligned CNT sheets allows for a concentration of millimeter long CNTs at the most likely point of laminate failure. Mode I and Mode II interlaminar fracture toughness of various CNT modified samples were investigated using double cantilever beam (DCB and end notched flexure (ENF experiments, respectively. Short beam strength (SBS and in-plane tensile properties of the CNT modified samples were also investigated. Moderate improvement was observed in Mode I and Mode II fracture toughness at crack initiation when aligned CNT sheets with a basis weight of 0.354 g/m2 were used to modify the ply interface. No compromise in the in-plane mechanical properties of the laminate was observed and very little improvement was observed in the shear related short beam strength of the CNT modified laminates as compared to the control samples. Integration of aligned CNT sheets into the composite laminate imparted in-plane and through thickness electrical properties into the nonconductive glass fiber reinforced epoxy composite laminates.

  16. Some recent developments in spin glasses

    Indian Academy of Sciences (India)

    A P Young

    2005-06-01

    I give some experimental and theoretical background to spin glasses, and then discuss the nature of the phase transition in spin glasses with vector spins. Results of Monte Carlo simulations of the Heisenberg spin glass model in three dimensions are presented. A finite-size scaling analysis of the correlation length of the spins and chiralities shows that there is a single, finite-temperature transition at which both spins and chiralities order.

  17. Embedded Health Monitoring for Glass Like Armor

    Science.gov (United States)

    2012-02-13

    container is then encased in a steel container. The circuit board needs to fit in the space between the glass plates and the plastic box...sides of the cube. Each circuit board is aligned with the glass plates so that it has four LED’s and four phototransistors used for detection per layer...of armor protection for vehicles which consists of several layers of glass plates . The plates are inserted in a plastic box and epoxy material is

  18. Archaeological and historical glasses: A bibliometric study

    OpenAIRE

    Palomar Sanz, Teresa; García Heras, Manuel; Villegas Broncano, María Ángeles

    2009-01-01

    Glass is one of the materials more widely developed throughout History. In the last decades, it has been stated a growing demand in the application of chemical-physical techniques to obtain more detailed information on technology and production of glasses in past societies. This research field lies within the domain of archaeometry. Results of a bibliometric study undertaken on 201 scientific articles published on ancient and historical glasses between 1987 and 2008 are presented ...

  19. Iron phosphate glass containing simulated fast reactor waste: Characterization and comparison with pristine iron phosphate glass

    Science.gov (United States)

    Joseph, Kitheri; Asuvathraman, R.; Venkata Krishnan, R.; Ravindran, T. R.; Govindaraj, R.; Govindan Kutty, K. V.; Vasudeva Rao, P. R.

    2014-09-01

    Detailed characterization was carried out on an iron phosphate glass waste form containing 20 wt.% of a simulated nuclear waste. High temperature viscosity measurement was carried out by the rotating spindle method. The Fe3+/Fe ratio and structure of this waste loaded iron phosphate glass was investigated using Mössbauer and Raman spectroscopy respectively. Specific heat measurement was carried out in the temperature range of 300-700 K using differential scanning calorimeter. Isoconversional kinetic analysis was employed to understand the crystallization behavior of the waste loaded iron phosphate glass. The glass forming ability and glass stability of the waste loaded glass were also evaluated. All the measured properties of the waste loaded glass were compared with the characteristics of pristine iron phosphate glass.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-09-01

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

  1. Healing of lithographically introduced flaws in glass and glass containing ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Ackler, H.D.

    1992-12-01

    The morphological evolution of cylindrical pores or channels'' and crack-like cavities in glass and glass-containing ceramics at elevated temperatures was studied. The systems studied were: Coming 7056 alkali borosilicate glass, soda-lime glass (microscope slides), a commercially available 96% Al[sub 2]O[sub 3]with [approx]5--10% intergranular glass, 96% Al[sub 2]O[sub 3] bonded to sapphire, and a model sapphire/glass/sapphire system fabricated by diffusion bonding etched and unetched pieces of sapphire onto which 30--50 nm of SiO[sub 2] had been sputter deposited. These systems span a broad range of glass contents, and permit observation of healing behavior with varying glass content. The results were compared with analytical models and results of similar studies in completely crystalline systems.

  2. Healing of lithographically introduced flaws in glass and glass containing ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Ackler, H.D.

    1992-12-01

    The morphological evolution of cylindrical pores or ``channels`` and crack-like cavities in glass and glass-containing ceramics at elevated temperatures was studied. The systems studied were: Coming 7056 alkali borosilicate glass, soda-lime glass (microscope slides), a commercially available 96% Al{sub 2}O{sub 3}with {approx}5--10% intergranular glass, 96% Al{sub 2}O{sub 3} bonded to sapphire, and a model sapphire/glass/sapphire system fabricated by diffusion bonding etched and unetched pieces of sapphire onto which 30--50 nm of SiO{sub 2} had been sputter deposited. These systems span a broad range of glass contents, and permit observation of healing behavior with varying glass content. The results were compared with analytical models and results of similar studies in completely crystalline systems.

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

    Science.gov (United States)

    Hill, Robert G; Brauer, Delia S

    2011-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Maddrell, Ewan, E-mail: ewan.r.maddrell@nnl.co.uk [National Nuclear Laboratory, Sellafield, Seascale, Cumbria CA20 1PG (United Kingdom); Thornber, Stephanie; Hyatt, Neil C. [Department of Materials Science and Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2015-01-15

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

  5. Glass Property Data and Models for Estimating High-Level Waste Glass Volume

    Energy Technology Data Exchange (ETDEWEB)

    Vienna, John D.; Fluegel, Alexander; Kim, Dong-Sang; Hrma, Pavel R.

    2009-10-05

    This report describes recent efforts to develop glass property models that can be used to help estimate the volume of high-level waste (HLW) glass that will result from vitrification of Hanford tank waste. The compositions of acceptable and processable HLW glasses need to be optimized to minimize the waste-form volume and, hence, to save cost. A database of properties and associated compositions for simulated waste glasses was collected for developing property-composition models. This database, although not comprehensive, represents a large fraction of data on waste-glass compositions and properties that were available at the time of this report. Glass property-composition models were fit to subsets of the database for several key glass properties. These models apply to a significantly broader composition space than those previously publised. These models should be considered for interim use in calculating properties of Hanford waste glasses.

  6. TBscore II

    DEFF Research Database (Denmark)

    Rudolf, Frauke; Lemvik, Grethe; Abate, Ebba;

    2013-01-01

    Abstract Background: The TBscore, based on simple signs and symptoms, was introduced to predict unsuccessful outcome in tuberculosis patients on treatment. A recent inter-observer variation study showed profound variation in some variables. Further, some variables depend on a physician assessing...... them, making the score less applicable. The aim of the present study was to simplify the TBscore. Methods: Inter-observer variation assessment and exploratory factor analysis were combined to develop a simplified score, the TBscore II. To validate TBscore II we assessed the association between start...

  7. STABILIZING GLASS BONDED WASTE FORMS CONTAINING FISSION PRODUCTS SEPARATED FROM SPENT NUCLEAR FUEL

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth J. Bateman; Charles W. Solbrig

    2008-07-01

    A model has been developed to represent the stresses developed when a molten, glass-bonded brittle cylinder (used to store nuclear material) is cooled from high temperature to working temperature. Large diameter solid cylinders are formed by heating glass or glass-bonded mixtures (mixed with nuclear waste) to high temperature (915°C). These cylinders must be cooled as the final step in preparing them for storage. Fast cooling time is desirable for production; however, if cooling is too fast, the cylinder can crack into many pieces. To demonstrate the capability of the model, cooling rate cracking data were obtained on small diameter (7.8 cm diameter) glass-only cylinders. The model and experimental data were combined to determine the critical cooling rate which separates the non-cracking stable glass region from the cracked, non-stable glass regime. Although the data have been obtained so far only on small glass-only cylinders, the data and model were used to extrapolate the critical-cooling rates for large diameter ceramic waste form (CWF) cylinders. The extrapolation estimates long term cooling requirements. While a 52-cm diameter cylinder (EBR-II-waste size) can be cooled to 100°C in 70 hours without cracking, a 181.5-cm diameter cylinder (LWR waste size) requires 35 days to cool to 100°C. These cooling times are long enough that verification of these estimates are required so additional experiments are planned on both glass only and CWF material.

  8. Recycling of glass: accounting of greenhouse gases and global warming contributions.

    Science.gov (United States)

    Larsen, Anna W; Merrild, Hanna; Christensen, Thomas H

    2009-11-01

    Greenhouse gas (GHG) emissions related to recycling of glass waste were assessed from a waste management perspective. Focus was on the material recovery facility (MRF) where the initial sorting of glass waste takes place. The MRF delivers products like cullet and whole bottles to other industries. Two possible uses of reprocessed glass waste were considered: (i) remelting of cullet added to glass production; and (ii) re-use of whole bottles. The GHG emission accounting included indirect upstream emissions (provision of energy, fuels and auxiliaries), direct activities at the MRF and bottle-wash facility (combustion of fuels) as well as indirect downstream activities in terms of using the recovered glass waste in other industries and, thereby, avoiding emissions from conventional production. The GHG accounting was presented as aggregated global warming factors (GWFs) for the direct and indirect upstream and downstream processes, respectively. The range of GWFs was estimated to 0-70 kg CO(2)eq. tonne( -1) of glass waste for the upstream activities and the direct emissions from the waste management system. The GWF for the downstream effect showed some significant variation between the two cases. It was estimated to approximately -500 kg CO(2)-eq. tonne(- 1) of glass waste for the remelting technology and -1500 to -600 kg CO(2)-eq. tonne(-1) of glass waste for bottle re-use. Including the downstream process, large savings of GHG emissions can be attributed to the waste management system. The results showed that, in GHG emission accounting, attention should be drawn to thorough analysis of energy sources, especially electricity, and the downstream savings caused by material substitution.

  9. Float glass innovation in the flat glass industry

    CERN Document Server

    Uusitalo, Olavi

    2014-01-01

    A thorough industry analysis is of utmost importance for a study on the impact of technological changes on industry structure. This book evaluates the consequences of a vaguely chosen level of an industry analysis. Too broad a definition of the industry may disaggregate sub-industries, processing industries and international aspects. This is illustrated by revisiting an industry study upon which the dominant design model was based. Readers will see and understand the consequences of too broadly defined industries together with quantitative research approach can have. The book argues that the nature of the industry should define the level of the analysis. This is done by revisiting the flat glass industry study, on which Anderson and Tushman’s (1990) dominant design model is partly based. In their study Anderson and Tushman defined the flat glass industry based on four-digit SIC codes. It is argued that this definition was too broad and it disaggregated important sub-industries, processing industries and int...

  10. Phase separation in an ionomer glass

    DEFF Research Database (Denmark)

    Pedersen, Malene Thostrup; Tian, K.V.; Dobó-Nagy, C.

    2015-01-01

    conclusively determined. In this work, we identify these phases by performing differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses on both the as-received glass and heat-treated samples. We detected three glass transitions in the as-received G338 glass during DSC upscaning, implying...... amorphous phases in G388 are Ca/Na-Al-Si-O, Ca-Al-F and Ca-P-O-F phases, respectively. However, the exact chemical compositions of the three phases still require further exploration. The results of this work are important for understanding the impact of phase separation within ionomer glasses on the setting...

  11. SOI silicon on glass for optical MEMS

    DEFF Research Database (Denmark)

    Larsen, Kristian Pontoppidan; Ravnkilde, Jan Tue; Hansen, Ole

    2003-01-01

    A newly developed fabrication method for fabrication of single crystalline Si (SCS) components on glass, utilizing Deep Reactive Ion Etching (DRIE) of a Silicon On Insulator (SOI) wafer is presented. The devices are packaged at wafer level in a glass-silicon-glass (GSG) stack by anodic bonding...... and a final sealing at the interconnects can be performed using a suitable polymer. Packaged MEMS on glass are advantageous within Optical MEMS and for sensitive capacitive devices. We report on experiences with bonding SOI to Pyrex. Uniform DRIE shallow and deep etching was achieved by a combination...

  12. Compliant Glass Seals for SOFC Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Y. S.; Choi, Jung-Pyung; Xu, Wei; Stephens, Elizabeth V.; Koeppel, Brian J.; Stevenson, Jeffry W.; Lara-Curzio, Edgar

    2014-04-01

    This report summarizes results from experimental and modeling studies performed by participants in the Solid-State Energy Conversion Alliance (SECA) Core Technology Program, which indicate that compliant glass-based seals offer a number of potential advantages over conventional seals based on de-vitrifying glasses, including reduced stresses during stack operation and thermal cycling, and the ability to heal micro-damage induced during thermal cycling. The properties and composition of glasses developed and/or investigated in these studies are reported, along with results from long-term (up to 5,800h) evaluations of seals based on a compliant glass containing ceramic particles or ceramic fibers.

  13. Compliant Glass Seals for SOFC Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Yeong -Shyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Choi, Jung-Pyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephens, Elizabeth V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Koeppel, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stevenson, Jeffry W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lara-Curzio, Edgar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-04-30

    This report summarizes results from experimental and modeling studies performed by participants in the Solid-State Energy Conversion Alliance (SECA) Core Technology Program, which indicate that compliant glass-based seals offer a number of potential advantages over conventional seals based on de-vitrifying glasses, including reduced stresses during stack operation and thermal cycling, and the ability to heal micro-damage induced during thermal cycling. The properties and composition of glasses developed and/or investigated in these studies are reported, along with results from long-term (up to 5,800h) evaluations of seals based on a compliant glass containing ceramic particles or ceramic fibers.

  14. Radiopaque strontium fluoroapatite glass-ceramics

    Directory of Open Access Journals (Sweden)

    Wolfram eHöland

    2015-10-01

    Full Text Available The controlled precipitation of strontium fluoroapatite crystals, was studied in four base glass compositions derived from the SiO2 – Al2O3 – Y2O3 – SrO – Na2O – K2O/Rb2O/Cs2O – P2O5 – F system. The crystal phase formation of these glasses and the main properties of the glass-ceramics, such as thermal and optical properties and radiopacity were compared with a fifth, a reference glass-ceramic. The reference glass-ceramic was characterized as Ca-fluoroapatite glass-ceramic. The four strontium fluoroapatite glass-ceramics showed the following crystal phases: a Sr5(PO43F – leucite, KAlSi2O6 , b Sr5(PO43F – leucite, KAlSi2O6, and nano-sized NaSrPO4 c Sr5(PO43F – pollucite, CsAlSiO4 , and nano-sized NaSrPO4, d Sr5(PO43F – Rb-leucite, RbAlSi2O6, and nano-sized NaSrPO4.The proof of crystal phase formation was possible by X-ray diffraction (XRD. The microstructures, which were studied using scanning electron microscopy (SEM demonstrated a uniform distribution of the crystals in the glass matrix. The Sr-fluoroapatites were precipitated based on an internal crystallization process, and the crystals demonstrated a needlelike morphology. The study of the crystal growth of needlelike Sr-fluoroapatites gave a clear evidence of an Ostwald ripening mechanism.The formation of leucite, pollucite and Rb-leucite was based on a surface crystallization mechanism. Therefore, a twofold crystallization mechanism was successfully applied to develop these types of glass-ceramics. The main focus of this study was the controlled development of glass-ceramics exhibiting high radiopacity in comparison to the reference glass-ceramic. This goal could be achieved with all four glass-ceramics with the preferred development of the Sr-fluoroapatite – pollucite-type glass-ceramic. In addition to this main development, it was possible to control the thermal properties. Especially the Rb-leucite containing glass-ceramic showed the highest coefficient of thermal

  15. Degradation of glass in the soil

    Energy Technology Data Exchange (ETDEWEB)

    Romich, H.; Gerlach, S.; Mottner, P. [Fraunhofer-Institut fur Silicatforschung (ISC), Wertheim-Bronnbach (Germany)

    2004-07-01

    Full text of publication follows: Glass has been produced and used in Europe for over 2000 years. Glass objects from the Roman period onwards have been excavated during the last centuries. In general, Roman glass is chemically quite stable, and often the only sign of chemical alteration is an iridescent surface, caused by the leaching of cations, which leads to the formation of a hydrated silica-rich layer. Medieval potash glasses are much less durable, and their surfaces are often found deeply leached, sometimes to a point that no unaltered glass remains. These surfaces may be coherent, though fragile, or they are laminar, with no cohesion between the layers at all. In this study an analytical examination of a series of fragments of archaeological glass retrieved from different sites near Cologne and Stuttgart (Germany) has been carried out. Samples of corroded glasses were analysed by optical microscopy and SEM/EDX (surface and cross sections) in order to obtain information about the chemical composition of the bulk glass and the weathered layers. Since the environmental parameters have constantly varied for archaeological objects, mechanistic studies have to rely on laboratory experiments under controlled conditions. For an extensive exposure programme standardised soil or natural garden earth was used, for which the pH was modified. Several corrosion sensitive potash-lime silicate glasses have been designed to study the effect of glass composition. A model glass consisting of SiO{sub 2} (54.2), CaO (28.8) and K{sub 2}O (17.0 weight-%) mostly lead to the formation of a crust on the leached layer, with a total thickness of 100 micrometer (for soil with pH 7 to 8, 12 months exposure). Model glasses also containing Al, Mg and P have built up preferably laminated structures (total thickness up to 200 micrometer). This presentation will give an overview about the variety of degradation phenomena observed on originals and compare the results with controlled laboratory

  16. Terbium-activated heavy scintillating glasses

    OpenAIRE

    Fu,J.; Kobayashi, M.; Parker, J.M.

    2008-01-01

    Tb-activated scintillating glasses with high Ln2O3 (Ln=Gd, Y, Lu) concentration up to 40mol% have been prepared. The effects of Ln3+ ions on the density, thermal properties, transmission and luminescence properties under both UV and X-ray excitation have been investigated. The glasses containing Gd2O3 or Lu2O3 exhibit a high density of more than 6.0g/cm3. Energy transfer from Gd3+ to Tb3+ takes place in Gd-containing glass and as a result the Gd-containing glass shows a light yield 2.5 times ...

  17. Integrated Glass Coating Manufacturing Line

    Energy Technology Data Exchange (ETDEWEB)

    Brophy, Brenor [Enki Technology Inc., San Jose, CA (United States)

    2015-09-30

    This project aims to enable US module manufacturers to coat glass with Enki’s state of the art tunable functionalized AR coatings at the lowest possible cost and highest possible performance by encapsulating Enki’s coating process in an integrated tool that facilitates effective process improvement through metrology and data analysis for greater quality and performance while reducing footprint, operating and capital costs. The Phase 1 objective was a fully designed manufacturing line, including fully specified equipment ready for issue of purchase requisitions; a detailed economic justification based on market prices at the end of Phase 1 and projected manufacturing costs and a detailed deployment plan for the equipment.

  18. Do atmospheric aerosols form glasses?

    Science.gov (United States)

    Zobrist, B.; Marcolli, C.; Pedernera, D. A.; Koop, T.

    2008-09-01

    A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline) solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg, homogeneous ice nucleation temperatures, Thom, and ice melting temperatures, Tm, of various aqueous inorganic, organic and multi-component solutions are investigated with a differential scanning calorimeter. The investigated solutes are: various polyols, glucose, raffinose, levoglucosan, an aromatic compound, sulfuric acid, ammonium bisulfate and mixtures of dicarboxylic acids (M5), of dicarboxylic acids and ammonium sulfate (M5AS), of two polyols, of glucose and ammonium nitrate, and of raffinose and M5AS. The results indicate that aqueous solutions of the investigated inorganic solutes show Tg values that are too low to be of atmospheric importance. In contrast, aqueous organic and multi-component solutions readily form glasses at low but atmospherically relevant temperatures (≤230 K). To apply the laboratory data to the atmospheric situation, the measured phase transition temperatures were transformed from a concentration to a water activity scale by extrapolating water activities determined between 252 K and 313 K to lower temperatures. The obtained state diagrams reveal that the higher the molar mass of the aqueous organic or multi-component solutes, the higher Tg of their respective solutions at a given water activity. To a lesser extent, Tg also depends on the hydrophilicity of the organic solutes. Therefore, aerosol particles containing larger (≳150 g mol-1) and more hydrophobic organic molecules are more likely to form glasses at intermediate to high relative humidities in the upper troposphere

  19. Glass-bead peen plating

    Science.gov (United States)

    Graves, J. R.

    1974-01-01

    Peen plating of aluminum, copper, and nickel powders was investigated. Only aluminum was plated successfully within the range of peen plating conditions studied. Optimum plating conditions for aluminum were found to be: (1) bead/powder mixture containing 25 to 35% powder by weight, (2) peening intensity of 0.007A as measured by Almen strip, and (3) glass impact bead diameter of at least 297 microns (0.0117 inches) for depositing-100 mesh aluminum powder. No extensive cleaning or substrate preparation is required beyond removing loose dirt or heavy oil.

  20. Do atmospheric aerosols form glasses?

    Directory of Open Access Journals (Sweden)

    D. A. Pedernera

    2008-09-01

    Full Text Available A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg, homogeneous ice nucleation temperatures, Thom, and ice melting temperatures, Tm, of various aqueous inorganic, organic and multi-component solutions are investigated with a differential scanning calorimeter. The investigated solutes are: various polyols, glucose, raffinose, levoglucosan, an aromatic compound, sulfuric acid, ammonium bisulfate and mixtures of dicarboxylic acids (M5, of dicarboxylic acids and ammonium sulfate (M5AS, of two polyols, of glucose and ammonium nitrate, and of raffinose and M5AS. The results indicate that aqueous solutions of the investigated inorganic solutes show Tg values that are too low to be of atmospheric importance. In contrast, aqueous organic and multi-component solutions readily form glasses at low but atmospherically relevant temperatures (≤230 K. To apply the laboratory data to the atmospheric situation, the measured phase transition temperatures were transformed from a concentration to a water activity scale by extrapolating water activities determined between 252 K and 313 K to lower temperatures. The obtained state diagrams reveal that the higher the molar mass of the aqueous organic or multi-component solutes, the higher Tg of their respective solutions at a given water activity. To a lesser extent, Tg also depends on the hydrophilicity of the organic solutes. Therefore, aerosol particles containing larger (≳150 g mol−1 and